Antibacterial polylactic acid melt-blown non-woven material and preparation method thereof

Abstract

The invention belongs to the field of non-woven materials, and particularly relates to an antibacterial polylactic acid melt-blown non-woven material and a preparation method thereof. The antibacterial polylactic acid melt-blown non-woven material provided by the invention comprises the following components: polylactic acid and an antibacterial polymer, the antibacterial polymer is one or more of polymers with structures as shown in formulas (I)-(IV). The novel N-halamine / quaternary ammonium salt composite antibacterial polymer is added into the polylactic acid melt-blown non-woven material, the composite antibacterial polymer can play a synergistic bactericidal role of various antibacterial agents, the application defect of a single antibacterial agent is overcome, and therefore the antibacterial performance of the polylactic acid melt-blown non-woven material is remarkably improved. The polylactic acid melt-blown non-woven material provided by the invention is simple and convenient in preparation process, excellent in antibacterial property, excellent in waste degradation property after being used, and good in practical value and environmental protection benefit. # imgabs0 #

Description

Technical Field

[0001] The present invention belongs to the field of non-woven materials, and particularly relates to an antibacterial polylactic acid meltblown non-woven material and a preparation method thereof. Background Art

[0002] In recent years, the problem of air pollution has become increasingly severe, and the market demand for high-performance filtration non-woven materials has also increased sharply. Such materials play an indispensable role in the fields of air purification and microbial prevention and control by virtue of their efficient filtration performance. Currently, the mainstream meltblown non-woven materials mostly use polypropylene as raw materials. However, polypropylene is a non-degradable material derived from petroleum, which will not only increase the energy burden in the future but also cause a series of serious environmental problems. In this context, bio-based meltblown non-woven materials have gradually come into people's view and become a research hotspot. With the increasingly prominent environmental pollution problems, it is urgent to develop degradable and renewable environmentally friendly polymer materials. Polylactic acid (PLA), as a bio-based material, has attracted much attention in the field of meltblown non-woven materials because it can be degraded in the natural environment and has almost no pollution to the environment. The polylactic acid meltblown non-woven material not only inherits the advantages of traditional meltblown non-woven materials such as large specific surface area, dense pores, and soft texture, but also has good biocompatibility and biodegradability, effectively alleviating the environmental pollution, resource waste, and sustainable development problems brought by traditional materials, highly conforming to the concept of sustainable development, and is gradually becoming the research focus in the non-woven field.

[0003] In different fields, if meltblown non-woven materials want to fully exert their excellent performance, it is crucial to improve their key performance specifically. The means to achieve this goal are diverse, covering the research and development of new raw materials, the optimization of preparation processes, and functional modification. Taking the improvement of antibacterial and antiviral properties as an example, in the production process of meltblown non-woven materials, an antibacterial agent with good antibacterial properties is incorporated, and the two are fully mixed by means of the meltblown process, which can endow the meltblown non-woven material with antibacterial and antiviral properties. In this way, the application scenarios of the material are greatly expanded, and it can better meet the actual needs of multiple fields such as medical treatment, hygiene, and air purification.

[0004] Currently, the common antibacterial polylactic acid meltblown non-woven materials on the market generally have the problem of relatively narrow antibacterial spectrum, and their antibacterial efficacy is often greatly reduced when encountering multiple microbial co-infections or complex contaminations. Summary of the Invention

[0005] In view of this, the purpose of the present invention is to provide an antibacterial polylactic acid meltblown non-woven material and a preparation method thereof, and the polylactic acid meltblown non-woven material provided by the present invention has excellent antibacterial properties.

[0006] The present invention provides an antibacterial polylactic acid meltblown nonwoven material, and the composition of the polylactic acid meltblown nonwoven material includes polylactic acid and an antibacterial polymer;

[0007] The antibacterial polymer is one or more of the polymers with the structures of formula (I) to formula (IV):

[0008]

[0009] In formula (I) to formula (IV), x, y, and z represent the degree of polymerization.

[0010] Preferably, in formula (I) to formula (IV), the ratio of x, y, and z is (5-8):(1-4):1; the weight-average molecular weight of the antibacterial polymer is 1000-2000 g / mol.

[0011] Preferably, the weight-average molecular weight of the polylactic acid is 1×10 5 -2×10 5 g / mol.

[0012] Preferably, the content of the antibacterial polymer in the polylactic acid meltblown nonwoven material is 1-5 wt%.

[0013] The present invention provides a preparation method of the antibacterial polylactic acid meltblown nonwoven material described in the above technical solution, including the following steps:

[0014] a) Melting and blending polylactic acid and an antibacterial polymer to obtain a blended material;

[0015] b) Meltblowing the blended material to obtain an antibacterial polylactic acid meltblown nonwoven material.

[0016] Preferably, the antibacterial polymer is prepared according to the following steps:

[0017] In the presence of an initiator, an N-haloamine precursor monomer, a quaternary ammonium salt monomer, and glycidyl methacrylate are subjected to a copolymerization reaction in a solvent to obtain an antibacterial polymer;

[0018] The N-haloamine precursor monomer is 1-allylhydantoin and / or 3-(4'-vinylbenzyl)-5,5-dimethylhydantoin;

[0019] The quaternary ammonium salt monomer is allyltrimethylammonium chloride and / or methacryloyloxyethyltrimethylammonium chloride.

[0020] Preferably, the initiator is potassium persulfate.

[0021] Preferably, the temperature of the copolymerization reaction is 70-90 °C, and the time is 4-8 h.

[0022] Preferably, the melt blending is carried out in a twin-screw extruder; the operating temperature of the twin-screw extruder is 170-190 °C, and the screw speed is 100-200 rpm.

[0023] Preferably, the meltblown forming is carried out by a meltblown machine; the operating temperature of the meltblown machine is 170-210 °C, and the screw speed is 100-200 rpm.

[0024] Compared with the prior art, the present invention provides an antibacterial polylactic acid meltblown nonwoven material and a preparation method thereof. The components of the antibacterial polylactic acid meltblown nonwoven material provided by the present invention include polylactic acid and an antibacterial polymer; the antibacterial polymer is one or more of the polymers with the structures of formula (I)-(IV). The present invention adds a novel N-haloamine / quaternary ammonium salt composite antibacterial polymer to the polylactic acid meltblown nonwoven material. This composite antibacterial polymer can play the synergistic bactericidal effect of each antibacterial agent, make up for the application defects of a single antibacterial agent, and thus significantly improve the antibacterial performance of the polylactic acid meltblown nonwoven material. The preparation process of the polylactic acid meltblown nonwoven material provided by the present invention is simple, has excellent antibacterial performance, and has excellent degradation performance of the waste after use, and has both good practical value and environmental protection benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only the embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained according to the provided drawings.

[0026] Figure 1 is the synthetic route diagram of the antibacterial polymer provided in Example 1 of the present invention;

[0027] Figure 2 is the infrared spectrum diagram of the antibacterial polymer provided in Example 1 of the present invention;

[0028] Figure 3 is the synthetic route diagram of the antibacterial polymer provided in Example 2 of the present invention;

[0029] Figure 4 is the infrared spectrum diagram of the antibacterial polymer provided in Example 2 of the present invention;

[0030] Figure 5 is the synthetic route diagram of the antibacterial polymer provided in Example 3 of the present invention;

[0031] Figure 6 is the infrared spectrum diagram of the antibacterial polymer provided in Example 3 of the present invention;

[0032] Figure 7It is the synthetic route diagram of the antibacterial polymer provided in Example 4 of the present invention;

[0033] Figure 8 It is the infrared spectrum diagram of the antibacterial polymer provided in Example 4 of the present invention. Detailed implementation manners

[0034] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0035] The present invention provides an antibacterial polylactic acid meltblown nonwoven material, the components of which include polylactic acid and an antibacterial polymer;

[0036] The antibacterial polymer is one or more of the polymers with the structures of formula (I) to formula (IV):

[0037]

[0038] In formula (I) to formula (IV), x, y, and z represent the degree of polymerization; the ratio of x, y, and z is preferably (5-8):(1-4):1, where the ratio of x to z can specifically be 5:1, 5.5:1, 6:1, 6.5:1, 7:1, 7.5:1, or 8:1, and the ratio of y to z can specifically be 1:1, 1.5:1, 2:1, 2.5:1, 3:1, 3.5:1, or 4:1.

[0039] In the polylactic acid meltblown nonwoven material provided by the present invention, the weight average molecular weight of the antibacterial polymer is preferably 1000-2000 g / mol, and can specifically be 1000 g / mol, 1100 g / mol, 1200 g / mol, 1300 g / mol, 1400 g / mol, 1500 g / mol, 1600 g / mol, 1700 g / mol, 1800 g / mol, 1900 g / mol, or 2000 g / mol.

[0040] In the polylactic acid meltblown nonwoven material provided by the present invention, the weight average molecular weight (M w ) of the polylactic acid is preferably 1×10 5 ~2×10 5g / mol, specifically, it can be 1 g / mol, 1.1 g / mol, 1.2 g / mol, 1.3 g / mol, 1.4 g / mol, 1.5 g / mol, 1.6 g / mol, 1.7 g / mol, 1.8 g / mol, 1.9 g / mol or 2 g / mol; the polydispersity index (PDI) of the polylactic acid is preferably 1-2, specifically, it can be 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9 or 2; the melt flow index (MFI) of the polylactic acid is preferably 30-70 g / 10 min, specifically, it can be 30 g / 10 min, 35 g / 10 min, 40 g / 10 min, 45 g / 10 min, 50 g / 10 min, 55 g / 10 min, 60 g / 10 min, 65 g / 10 min or 70 g / 10 min.

[0041] In the polylactic acid meltblown nonwoven material provided by the present invention, the content of the antibacterial polymer in the polylactic acid meltblown nonwoven material is preferably 1-5 wt%, specifically, it can be 1 wt%, 1.5 wt%, 2 wt%, 2.5 wt%, 3 wt%, 3.5 wt%, 4 wt%, 4.5 wt% or 5 wt%.

[0042] The present invention also provides a preparation method of the antibacterial polylactic acid meltblown nonwoven material described in the above technical solution, including the following steps:

[0043] a) Melting and blending polylactic acid and an antibacterial polymer to obtain a blended material;

[0044] b) Meltblowing the blended material to form an antibacterial polylactic acid meltblown nonwoven material.

[0045] In the preparation method provided by the present invention, in step a), the antibacterial polymer is preferably prepared according to the following steps:

[0046] In the presence of an initiator, an N-haloamine precursor monomer, a quaternary ammonium salt monomer and glycidyl methacrylate (GMA) carry out a copolymerization reaction in a solvent to obtain an antibacterial polymer;

[0047] The N-haloamine precursor monomer is 1-allylhydantoin (AH) and / or 3-(4'-vinylbenzyl)-5,5-dimethylhydantoin (VBDMH);

[0048] The quaternary ammonium salt monomer is allyltrimethylammonium chloride (ATAC) and / or methacryloyloxyethyltrimethylammonium chloride (DMC).

[0049] In the above antibacterial polymer preparation step provided by the present invention, the chemical structure of the 1-allylhydantoin is shown in formula (i):

[0050]

[0051] In the above-mentioned preparation steps of the antibacterial polymer provided by the present invention, the chemical structure of 3-(4'-vinylbenzyl)-5,5-dimethylhydantoin is shown in formula (ii):

[0052]

[0053] In the above-mentioned preparation steps of the antibacterial polymer provided by the present invention, the chemical structure of allyltrimethylammonium chloride is shown in formula (iii):

[0054]

[0055] In the above-mentioned preparation steps of the antibacterial polymer provided by the present invention, the chemical structure of methacryloyloxyethyltrimethylammonium chloride is shown in formula (iv):

[0056]

[0057] In the above-mentioned preparation steps of the antibacterial polymer provided by the present invention, the chemical structure of glycidyl methacrylate is shown in formula (v):

[0058]

[0059] In the above-mentioned preparation steps of the antibacterial polymer provided by the present invention, the molar ratio of the N-haloamine precursor monomer, the quaternary ammonium salt monomer to glycidyl methacrylate is preferably (5-8):(1-4):1; wherein, the molar ratio of the N-haloamine precursor monomer to glycidyl methacrylate can specifically be 5:1, 5.5:1, 6:1, 6.5:1, 7:1, 7.5:1 or 8:1; the molar ratio of the quaternary ammonium salt monomer to glycidyl methacrylate can specifically be 1:1, 1.5:1, 2:1, 2.5:1, 3:1, 3.5:1 or 4:1.

[0060] In the above-mentioned preparation steps of the antibacterial polymer provided by the present invention, the initiator is preferably potassium persulfate (KPS).

[0061] In the above-mentioned preparation steps of the antibacterial polymer provided by the present invention, the solvent is preferably an organic solvent and / or water; the organic solvent is preferably acetonitrile.

[0062] In the above-mentioned preparation steps of the antibacterial polymer provided by the present invention, the copolymerization reaction is preferably carried out under anaerobic conditions; the temperature of the copolymerization reaction is preferably 70-90°C, specifically 70°C, 75°C, 80°C, 85°C or 90°C; the time of the copolymerization reaction is preferably 4-8 h, specifically 4 h, 4.5 h, 5 h, 5.5 h, 6 h, 6.5 h, 7 h, 7.5 h or 8 h.

[0063] In the above-mentioned preparation steps of the antibacterial polymer provided by the present invention, the specific operation of carrying out the copolymerization reaction preferably includes:

[0064] Mix the N-haloamine precursor monomer with an organic solvent to obtain an N-haloamine precursor monomer solution; mix the quaternary ammonium salt monomer with water to obtain a quaternary ammonium salt monomer solution; mix the N-haloamine precursor monomer solution, the quaternary ammonium salt monomer solution and glycidyl methacrylate in a reaction device, then remove the oxygen in the reaction device, then heat the reaction device to the required reaction temperature, then add an aqueous solution of an initiator to the reaction device, and then carry out the copolymerization reaction under insulation.

[0065] In the above-mentioned preparation steps of the antibacterial polymer provided by the present invention, after the copolymerization reaction is completed, the reaction product is post-treated to obtain an antibacterial polymer. Among them, the post-treatment process preferably includes filtration, washing and drying in sequence.

[0066] In the above-mentioned preparation steps of the antibacterial polymer provided by the present invention, when the N-haloamine precursor monomer used is 3-(4'-vinylbenzyl)-5,5-dimethylhydantoin and the quaternary ammonium salt monomer is allyltrimethylammonium chloride, the obtained antibacterial polymer has the structure of formula (I); when the N-haloamine precursor monomer used is 3-(4'-vinylbenzyl)-5,5-dimethylhydantoin and the quaternary ammonium salt monomer is methacryloyloxyethyltrimethylammonium chloride, the obtained antibacterial polymer has the structure of formula (II); when the N-haloamine precursor monomer used is 1-allylhydantoin and the quaternary ammonium salt monomer is allyltrimethylammonium chloride, the obtained antibacterial polymer has the structure of formula (III); when the N-haloamine precursor monomer used is 1-allylhydantoin and the quaternary ammonium salt monomer is methacryloyloxyethyltrimethylammonium chloride, the obtained antibacterial polymer has the structure of formula (IV).

[0067] In the preparation method provided by the present invention, in step a), the melt blending is preferably carried out in a twin-screw extruder; the operating temperature of the twin-screw extruder is preferably 170-190 °C, more specifically: the temperature of zone 1 is 170-175 °C, the temperature of zone 2 is 170-175 °C, the temperature of zone 3 is 180-185 °C, the temperature of zone 4 is 185-190 °C, the temperature of zone 5 is 185-190 °C, the temperature of zone 6 is 185-190 °C, the temperature of zone 7 is 185-190 °C, the temperature of zone 8 is 185-190 °C, and the temperature of the die head is 180-190 °C; the screw speed of the twin-screw extruder is preferably 100-200 rpm, and specifically can be 100 rpm, 110 rpm, 120 rpm, 130 rpm, 140 rpm, 150 rpm, 160 rpm, 170 rpm, 180 rpm, 190 rpm or 200 rpm.

[0068] In the preparation method provided by the present invention, in step a), after the melt blending, it is preferred to pelletize the obtained mixture to obtain pelletized materials.

[0069] In the preparation method provided by the present invention, in step b), the meltblowing is preferably carried out by a meltblowing machine; the operating temperature of the meltblowing machine is preferably 170-210 °C, more specifically: the temperature of zone 1 is 170-180 °C, the temperature of zone 2 is 180-190 °C, the temperature of zone 3 is 190-200 °C, the temperature of zone 4 is 200-210 °C, and the temperature of zone 5 is 200-210 °C; the screw speed of the meltblowing machine is preferably 100-200 rpm, and specifically can be 100 rpm, 110 rpm, 120 rpm, 130 rpm, 140 rpm, 150 rpm, 160 rpm, 170 rpm, 180 rpm, 190 rpm or 200 rpm.

[0070] The technical solution provided by the present invention adds a novel N-haloamine / quaternary ammonium salt composite antibacterial polymer to the polylactic acid meltblown nonwoven material. This composite antibacterial polymer can exert the synergistic bactericidal effect of each antibacterial agent, make up for the application defects of a single antibacterial agent, and thus significantly improve the antibacterial performance of the polylactic acid meltblown nonwoven material. The preparation process of the polylactic acid meltblown nonwoven material provided by the present invention is simple, the antibacterial performance is excellent, the degradation performance of the waste after use is excellent, and it has both good practical value and environmental benefits.

[0071] For the sake of clarity, the following will be described in detail through the following examples and comparative examples.

[0072] In the following examples and comparative examples of the present invention, the polylactic acid (PLA) used was provided by Zhejiang Hisun Biomaterials Co., Ltd., grade: REVODE290, M w : 1.3×10 5g / mol, PDI: 1.41, MFI: 50 g / 10 min.

[0073] Example 1

[0074] (1) Synthesis of the antibacterial polymer. The synthesis route is as Figure 1 shown, and the specific process is as follows:

[0075] In the experimental preparation stage, 15.50 g of 3-(4′-vinylbenzyl)-5,5-dimethylhydantoin (VBDMH) was weighed and slowly added to the acetonitrile solution, and the container was gently shaken to promote its complete dissolution. Another 4.07 g of allyltrimethylammonium chloride (ATAC) was dissolved in deionized water, and continuous stirring was carried out until ATAC was completely dissolved. The uniformly dissolved VBDMH solution and ATAC solution, together with 1.42 g of glycidyl methacrylate (GMA), were added to a 500 mL three-necked flask. The magnetic stirring device was turned on, the rotation speed was set at 200 - 300 r / min, and the mixture was stirred at room temperature for 20 minutes. At the same time, nitrogen was introduced into the flask to completely exhaust the oxygen therein. After the preliminary operations were completed, the three-necked flask was placed in a water bath for heating, and the system temperature was gradually raised to 80 °C. Then, 1.08 g of an aqueous potassium persulfate (KPS) solution (concentration: 1 wt%) was added, and the reaction was carried out at this temperature for 6 hours. After the reaction was completed, the precipitated polymer particles were filtered using filter paper and a Buchner funnel. The filtered polymer particles were washed repeatedly with ethanol and deionized water three times to remove impurities. Finally, the washed polymer particles were placed in a vacuum drying oven at 50 °C and dried for 24 hours to obtain the final product, namely the copolymer of VBDMH, ATAC, and GMA, P(VBDMH-co-ATAC-co-GMA), whose structure is shown in formula (I) (x:y:z = 6:3:1), and the weight-average molecular weight is 1800 g / mol.

[0076] The infrared characterization of the above-prepared antibacterial polymer was carried out, and the results are as Figure 2 shown.

[0077] (2) Preparation of the antibacterial polylactic acid meltblown nonwoven material:

[0078] The polylactic acid and the P(VBDMH-co-ATAC-co-GMA) antibacterial polymer were respectively blended at the blending ratios of 99:1, 98:3, and 95:5 (mass ratio). After being mixed evenly, they were melt-blended by a twin-screw extruder and then pelletized to obtain the polylactic acid meltblown special resin. Then, the polylactic acid meltblown special resin was added to a meltblown machine for meltblown molding, and finally the antibacterial polylactic acid meltblown nonwoven material was obtained.

[0079] In this embodiment, the set temperatures of the twin-screw extruder are as follows: zone 1: 170 - 175°C, zone 2: 170 - 175°C, zone 3: 180 - 185°C, zone 4: 185 - 190°C, zone 5: 185 - 190°C, zone 6: 185 - 190°C, zone 7: 185 - 190°C, zone 8: 185 - 190°C, head: 180 - 190°C, and the screw speed is 100 - 200 rpm.

[0080] In this embodiment, the set temperatures of the meltblown machine are as follows: zone 1: 170 - 180°C, zone 2: 180 - 190°C, zone 3: 190 - 200°C, zone 4: 200 - 210°C, zone 5: 200 - 210°C, and the screw speed is 100 - 200 rpm.

[0081] Example 2

[0082] (1) Synthesis of the antibacterial polymer. The synthesis route is as Figure 3 shown, and the specific process is as follows:

[0083] In the experimental preparation stage, weigh 15.50 g of 3-(4′-vinylbenzyl)-5,5-dimethylhydantoin (VBDMH), and slowly add it to the acetonitrile solution. Gently shake the container to promote its full dissolution. Separately, take 6.23 g of methacryloyloxyethyltrimethylammonium chloride (DMC), dissolve it in deionized water, and continuously stir until DMC is completely dissolved. Add the uniformly dissolved VBDMH solution and DMC solution, together with 1.42 g of glycidyl methacrylate (GMA), into a 500 mL three-necked flask. Turn on the magnetic stirring device, set the rotation speed at 200 - 300 r / min, stir at room temperature for 20 minutes, and simultaneously introduce nitrogen into the flask to completely exhaust the oxygen in it. After completing the preliminary operations, place the three-necked flask in a water bath for heating, gradually raise the system temperature to 80°C, then add 1.08 g of an aqueous solution of potassium persulfate (KPS) (concentration: 1 wt%), and react fully at this temperature for 6 hours. After the reaction is completed, filter the precipitated polymer particles using filter paper and a Buchner funnel. Wash the filtered polymer particles with ethanol and deionized water repeatedly 3 times to remove impurities. Finally, put the washed polymer particles into a vacuum drying oven at 50°C and dry for 24 hours to obtain the final product, namely the copolymer of VBDMH, DMC, and GMA, P(VBDMH-co-DMC-co-GMA), whose structure is as shown in formula (II) (x:y:z = 6:3:1), and the weight-average molecular weight is 1900 g / mol.

[0084] Perform infrared characterization on the above-prepared antibacterial polymer, and the results are as Figure 4 shown.

[0085] (2) Preparation of the antibacterial polylactic acid meltblown nonwoven material:

[0086] The polylactic acid and the P(VBDMH-co-DMC-co-GMA) antibacterial polymer were blended at the blending ratios (mass ratio) of 99:1, 98:3, and 95:5 respectively. After being mixed evenly, they were melt-blended by a twin-screw extruder and then pelletized to obtain the special polylactic acid meltblown resin. Then, the special polylactic acid meltblown resin was added to a meltblowing machine for meltblown molding, and finally, the antibacterial polylactic acid meltblown nonwoven material was obtained.

[0087] In this example, the set temperatures of the twin-screw extruder were as follows: zone 1: 170 - 175 °C, zone 2: 170 - 175 °C, zone 3: 180 - 185 °C, zone 4: 185 - 190 °C, zone 5: 185 - 190 °C, zone 6: 185 - 190 °C, zone 7: 185 - 190 °C, zone 8: 185 - 190 °C, and the head: 180 - 190 °C. The screw speed was 100 - 200 rpm.

[0088] In this example, the set temperatures of the meltblowing machine were as follows: zone 1: 170 - 180 °C, zone 2: 180 - 190 °C, zone 3: 190 - 200 °C, zone 4: 200 - 210 °C, zone 5: 200 - 210 °C. The screw speed was 100 - 200 rpm.

[0089] Example 3

[0090] (1) Synthesis of the antibacterial polymer. The synthesis route is as Figure 5 shown, and the specific process is as follows:

[0091] In the experimental preparation stage, 8.41 g of 1-allyl hydantoin (AH) was weighed and slowly added to the acetonitrile solution. The container was gently shaken to promote its complete dissolution. Another 4.07 g of allyltrimethylammonium chloride (ATAC) was dissolved in deionized water, and continuous stirring was carried out until ATAC was completely dissolved. The uniformly dissolved AH solution and ATAC solution, together with 1.42 g of glycidyl methacrylate (GMA), were added to a 500 mL three-necked flask. The magnetic stirring device was turned on, and the rotation speed was set at 200 - 300 r / min. Stirring was carried out at room temperature for 20 minutes, and nitrogen was introduced into the flask to completely exhaust the oxygen therein. After the preliminary operations were completed, the three-necked flask was placed in a water bath for heating, and the system temperature was gradually raised to 80 °C. Then, 1.08 g of an aqueous solution of potassium persulfate (KPS) (concentration: 1 wt%) was added, and the reaction was allowed to proceed fully at this temperature for 6 hours. After the reaction was completed, the precipitated polymer particles were filtered using filter paper and a Buchner funnel. The filtered polymer particles were washed repeatedly 3 times with ethanol and deionized water to remove impurities. Finally, the washed P(AH-co-ATAC-co-GMA) polymer particles were placed in a vacuum drying oven at 50 °C and dried for 24 hours to obtain the final product, namely the copolymer of AH, ATAC, and GMA, P(AH-co-ATAC-co-GMA), whose structure is shown in formula (III) (x:y:z = 6:3:1), and the weight-average molecular weight is 1100 g / mol.

[0092] The infrared characterization of the above-prepared antibacterial polymer was carried out, and the results are as Figure 6 shown.

[0093] (2) Preparation of antibacterial polylactic acid meltblown nonwoven materials:

[0094] Polylactic acid and the P(AH-co-ATAC-co-GMA) antibacterial polymer were respectively blended at mass ratios of 99:1, 98:3, and 95:5. After being mixed evenly, they were melt-blended by a twin-screw extruder and then pelletized to obtain a special polylactic acid meltblown resin. Then, the special polylactic acid meltblown resin was added to a meltblown machine for meltblown molding, and finally, antibacterial polylactic acid meltblown nonwoven materials were prepared.

[0095] In this example, the set temperatures of the twin-screw extruder were: zone 1: 170 - 175 °C, zone 2: 170 - 175 °C, zone 3: 180 - 185 °C, zone 4: 185 - 190 °C, zone 5: 185 - 190 °C, zone 6: 185 - 190 °C, zone 7: 185 - 190 °C, zone 8: 185 - 190 °C, and the head: 180 - 190 °C. The screw rotation speed was 100 - 200 rpm.

[0096] In this embodiment, the set temperatures of the meltblown machine are: Zone 1: 170 - 180 °C, Zone 2: 180 - 190 °C, Zone 3: 190 - 200 °C, Zone 4: 200 - 210 °C, Zone 5: 200 - 210 °C, and the screw speed is 100 - 200 rpm.

[0097] Example 4

[0098] (1) Synthesis of the antibacterial polymer. The synthesis route is as Figure 7 shown, and the specific process is as follows:

[0099] In the experimental preparation stage, 8.41 g of 1-allyl hydantoin (AH) was weighed and slowly added to the acetonitrile solution, and the container was gently shaken to promote its complete dissolution. Another 6.23 g of methylacryloyloxyethyl trimethyl ammonium chloride (DMC) was dissolved in deionized water and continuously stirred until DMC was completely dissolved. The uniformly dissolved AH solution and DMC solution, together with 1.42 g of glycidyl methacrylate (GMA), were added to a 500 mL four-necked flask. The magnetic stirring device was turned on, the rotation speed was set at 200 - 300 r / min, and the mixture was stirred at room temperature for 20 minutes. At the same time, nitrogen was introduced into the flask to completely exhaust the oxygen therein. After completing the preliminary operations, the four-necked flask was placed in a water bath for heating to gradually raise the system temperature to 80 °C, and then 1.08 g of an aqueous potassium persulfate (KPS) solution (concentration: 1 wt%) was added. The reaction was carried out at this temperature for 6 hours. After the reaction ended, the precipitated polymer particles were filtered using filter paper and a Buchner funnel. The filtered polymer particles were washed repeatedly with ethanol and deionized water three times to remove impurities. Finally, the washed P(AH-co-DMC-co-GMA) polymer particles were placed in a vacuum drying oven at 50 °C and dried for 24 hours to obtain the final product, namely the copolymer of AH, DMC, and GMA, P(AH-co-DMC-co-GMA), whose structure is as shown in formula (IV) (x:y:z = 6:3:1), and the weight-average molecular weight is 1300 g / mol.

[0100] The infrared characterization of the above-prepared antibacterial polymer is as Figure 8 shown.

[0101] (2) Preparation of the antibacterial polylactic acid meltblown nonwoven material:

[0102] Polylactic acid and the P(AH-co-DMC-co-GMA) antibacterial polymer were respectively blended at mass ratios of 99:1, 98:3, and 95:5. After being mixed evenly, they were melt-blended by a twin-screw extruder and then pelletized to obtain the special resin for polylactic acid meltblowing. Then, the special resin for polylactic acid meltblowing was added to a meltblown machine for meltblown molding to finally obtain the antibacterial polylactic acid meltblown nonwoven material.

[0103] In this embodiment, the set temperatures of the twin-screw extruder are: Zone 1: 170 - 175°C, Zone 2: 170 - 175°C, Zone 3: 180 - 185°C, Zone 4: 185 - 190°C, Zone 5: 185 - 190°C, Zone 6: 185 - 190°C, Zone 7: 185 - 190°C, Zone 8: 185 - 190°C, and the head: 180 - 190°C. The screw speed is 100 - 200 rpm.

[0104] In this embodiment, the set temperatures of the meltblown machine are: Zone 1: 170 - 180°C, Zone 2: 180 - 190°C, Zone 3: 190 - 200°C, Zone 4: 200 - 210°C, Zone 5: 200 - 210°C. The screw speed is 100 - 200 rpm.

[0105] Comparative Example 1

[0106] Preparation of polylactic acid meltblown nonwoven material:

[0107] The polylactic acid is melted and extruded into pellets by a twin-screw extruder to obtain a special resin for polylactic acid meltblown. Then, the special resin for polylactic acid meltblown is added to the meltblown machine for meltblown molding, and finally, the polylactic acid meltblown nonwoven material is obtained.

[0108] In this embodiment, the set temperatures of the twin-screw extruder are: Zone 1: 170 - 175°C, Zone 2: 170 - 175°C, Zone 3: 180 - 185°C, Zone 4: 185 - 190°C, Zone 5: 185 - 190°C, Zone 6: 185 - 190°C, Zone 7: 185 - 190°C, Zone 8: 185 - 190°C, and the head: 180 - 190°C. The screw speed is 100 - 200 rpm.

[0109] In this embodiment, the set temperatures of the meltblown machine are: Zone 1: 170 - 180°C, Zone 2: 180 - 190°C, Zone 3: 190 - 200°C, Zone 4: 200 - 210°C, Zone 5: 200 - 210°C. The screw speed is 100 - 200 rpm.

[0110] Antibacterial performance test

[0111] It is detected by Gram-positive Staphylococcus aureus (S. aureus, ATCC 6538) and Gram-negative Escherichia coli (E. coli, CMCC 44103). Staphylococcus aureus and Escherichia coli are cultured in broth medium at 37°C for 24 h for standby. The cultured bacterial solution is diluted to 10 with phosphate buffer solution (PBS) 4About CFU / mL. Take 50 μL of fresh bacterial suspension solution and drop it on the surface of the meltblown nonwoven material to ensure full contact between the bacterial solution and the meltblown fabric. After a contact time of 12 h, place the meltblown nonwoven material in 5 mL of PBS buffer solution and vortex for 2 min. Dilute it with PBS buffer in gradients, place each dilution on a corresponding agar plate, and after culturing in an incubator at 37 °C for 24 h, count the number of colonies on the agar plate.

[0112] The antibacterial test results of the meltblown nonwoven materials prepared in different examples and comparative examples against Staphylococcus aureus and Escherichia coli are shown in Table 1:

[0113] Table 1 Antibacterial test data table of meltblown nonwoven materials.

[0114]

[0115] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. An antibacterial polylactic acid meltblown nonwoven material, characterized in that, The composition of the polylactic acid meltblown nonwoven material includes polylactic acid and an antibacterial polymer; The antibacterial polymer is one or more of the polymers with the structures of formula (I) to formula (IV): In formula (I) to formula (IV), x, y and z represent the degree of polymerization.

2. The polylactic acid meltblown nonwoven material according to claim 1, wherein, In formula (I) to formula (IV), the ratio of x, y to z is (5 - 8):(1 - 4):1; the weight average molecular weight of the antibacterial polymer is 1000 - 2000 g / mol.

3. The polylactic acid meltblown nonwoven material according to claim 1, wherein The weight-average molecular weight of the polylactic acid is 1×10 5 ~2×10 5 g / mol.

4. The polylactic acid meltblown nonwoven material according to claim 1, wherein The content of the antibacterial polymer in the polylactic acid meltblown nonwoven material is 1 - 5 wt%.

5. A method for preparing the antibacterial polylactic acid meltblown nonwoven material according to any one of claims 1 to 4, characterized in that, It includes the following steps: a) Melt-blend polylactic acid and the antibacterial polymer to obtain a blended material; b) Melt-blown the blended material to obtain an antibacterial polylactic acid meltblown nonwoven material.

6. The preparation method according to claim 5, characterized in that, The antibacterial polymer is prepared according to the following steps: In the presence of an initiator, the N-haloamine precursor monomer, the quaternary ammonium salt monomer and glycidyl methacrylate carry out a copolymerization reaction in a solvent to obtain the antibacterial polymer; The N-haloamine precursor monomer is 1-allylhydantoin and / or 3-(4'-vinylbenzyl)-5,5-dimethylhydantoin; The quaternary ammonium salt monomer is allyltrimethylammonium chloride and / or methacryloyloxyethyltrimethylammonium chloride.

7. The preparation method according to claim 6, characterized in that The initiator is potassium persulfate.

8. The preparation method according to claim 6, characterized in that, The temperature of the copolymerization reaction is 70 - 90 °C, and the time is 4 - 8 h.

9. The preparation method according to claim 5, wherein The melt-blending is carried out in a twin-screw extruder; the operating temperature of the twin-screw extruder is 170 - 190 °C, and the screw speed is 100 - 200 rpm.

10. The preparation method according to claim 5, characterized in that, The melt-blown forming is carried out by a melt-blown machine; the operating temperature of the melt-blown machine is 170 - 210 °C, and the screw speed is 100 - 200 rpm.

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