Functionalized spinning of ultraviolet-proof antibacterial polypropylene filament yarn and process method thereof

Abstract

The invention discloses functional spinning of ultraviolet-proof antibacterial polypropylene filament yarns and a process method thereof, and belongs to the technical field of modified polypropylene fibers. The preparation method comprises the following steps: dissolving caffeic acid in ethanol, then adding ZnO nanoparticles, carrying out ultrasonic dispersion, and then sequentially carrying out reflux reaction, centrifugal separation and drying to obtain a CA-ZnO compound; dissolving dopamine hydrochloride in a Tris buffer solution, then adding the CA-ZnO compound, and carrying out a stirring reaction; after the reaction is finished, centrifuging to obtain a CA-ZnO (at) PDA nanocapsule; mixing, heating and stirring polypropylene and [BMIM] Cl to obtain a first mixed solution for later use; taking part of the first mixed solution, adding CA-ZnO (at) PDA, and continuously mixing uniformly to obtain a second mixed solution; the first mixed solution and the second mixed solution are subjected to microfluidic electrostatic spinning and then placed in a supercritical CO2 reaction kettle to be treated, and the ultraviolet-proof antibacterial polypropylene filament yarn is obtained. The invention breaks through the bottlenecks of single function, poor durability and the like of the traditional polypropylene fiber, has the advantages of high antibacterial property, ultraviolet resistance, high strength and green manufacturing, and is suitable for the high value-added fields of medical protection, outdoor equipment and the like.

Description

Technical Field

[0001] The invention belongs to the technical field of modified polypropylene fibers, and particularly relates to functional spinning of ultraviolet-proof and antibacterial polypropylene filaments and a process method thereof. Background Art

[0002] Polypropylene (PP fiber) is widely used in the textile field due to its light weight, wear resistance, corrosion resistance and high strength. However, the large number of methyl side chains in its molecular chain are easily oxidized and degraded by ultraviolet (UV) radiation, resulting in problems such as decreased mechanical properties and embrittlement of the fiber. In addition, it naturally lacks antibacterial function, which greatly limits its application in high value-added scenarios such as outdoor protection and medical textiles. In recent years, giving polypropylene anti-UV and antibacterial properties through functional modification has become a research hotspot, but the existing technology still has the following significant defects: Traditional modification methods mostly use single functional additives (such as adding only nano-TiO2 or Ag particles), which makes it difficult to achieve synergistic enhancement of anti-UV and antibacterial effects. Physically blended inorganic particles are easy to agglomerate, resulting in a fiber breakage rate of more than 5%, and the interface bonding between the additive and the matrix is weak, resulting in poor functional durability. When adding inorganic fillers, if the dispersion is uneven or the interface compatibility is poor, the regularity of the polypropylene molecular chain will be destroyed, resulting in a decrease in fiber strength of more than 20%. Furthermore, in traditional melt-spinning processes, high temperatures can easily cause thermal decomposition of additives (e.g., oxidation of Ag nanoparticles), limiting the selection of functional additives. Existing technologies often rely on toxic solvents (e.g., xylene) or complex surface modification processes (e.g., multiple coupling agent treatments), increasing production costs and the risk of environmental pollution. Summary of the Invention

[0003] In view of this, the purpose of the present invention is to provide functional spinning of UV-proof and antibacterial polypropylene filaments and a process method thereof. The present invention successfully solves the problems of traditional polypropylene fibers such as single function, poor durability, and high process pollution, and achieves the synergistic optimization of antibacterial, UV-resistant, high strength and environmental friendliness, and is suitable for high value-added fields such as medical care and outdoor protection.

[0004] In order to achieve the above object, the present invention provides the following technical solutions:

[0005] The present invention provides a process for preparing ultraviolet-proof and antibacterial polypropylene filaments, comprising the following steps:

[0006] S1. Caffeic acid was dissolved in ethanol, and then ZnO nanoparticles were added for ultrasonic dispersion. The mixture was then refluxed, centrifuged, and dried to obtain a CA-ZnO composite.

[0007] S2. Dopamine hydrochloride was dissolved in Tris buffer, and then the CA-ZnO complex was added and stirred for reaction. After the reaction was completed, the CA-ZnO@PDA nanocapsules were obtained by centrifugation.

[0008] S3. The polypropylene and [BMIM] Cl were mixed and heated with stirring to obtain a first mixed solution for standby use;

[0009] Take part of the first mixed solution and add CA-ZnO@PDA and continue to mix evenly to obtain the second mixed solution;

[0010] The first mixed liquid and the second mixed liquid are subjected to microfluidic electrospinning and then placed in a supercritical CO2 reactor for treatment to obtain UV-resistant and antibacterial polypropylene filaments.

[0011] The present invention adopts the above technical solution to prepare anti-ultraviolet and antibacterial polypropylene filaments; wherein caffeic acid-ZnO / polydopamine hybrid nanocapsules (CA-ZnO@PDA) are used, and the coordination effect of plant polyphenols (caffeic acid) and ZnO is used to form a photosensitive antibacterial network, and the polydopamine shell provides ultraviolet absorption (280-400nm) and free radical scavenging functions. Under ultraviolet or visible light irradiation, CA-ZnO@PDA releases reactive oxygen species (ROS) and ZnO. 2+ , achieving dual sterilization of "photodynamic + metal ion". Polydopamine undergoes dynamic cross-linking under light, repairing the micro-cracks on the fiber surface caused by washing.

[0012] Furthermore, as polypropylene (PP) is a non-polar polymer, its melt viscosity is high and it lacks conductivity. Traditional electrospinning requires the use of toxic solvents (such as xylene) or high-temperature melting (>200°C), which makes the process complex and difficult to control. The ionic liquid [BMIM]Cl (1-butyl-3-methylimidazolium chloride) was selected. Its cation (BMIM + ) forms a physical crosslinking network with polypropylene chains through van der Waals forces and weak dipole interactions, significantly reducing melt viscosity while imparting electrical conductivity to the PP melt, meeting the electric field-induced jet stretching requirements of electrospinning. Recycling through water washing or supercritical CO2 extraction achieves a green process. Furthermore, the ionic liquid acts as a "plasticizer" by inserting itself between molecular chains, disrupting their regular crystalline structure and forming a thermoreversible physical gel.

[0013] The present invention uses microfluidic technology to achieve spatially controlled distribution of functional components (CA-ZnO@PDA) inside the fiber, forming a gradient structure of core layer and sheath layer. After being treated in a supercritical CO2 reactor, scCO2 dissolves in trace moisture on the fiber surface to generate carbonic acid, which causes the local pH to drop, triggering the ZnO@PDA in CA-ZnO@PDA to form a gradient structure of core layer and sheath layer. 2+ The ZnCO3 precursor is released and then dehydrated on the surface to form ZnO whiskers. This allows the in-situ ZnO whiskers to be embedded in the sheath layer, forming a physical barrier that reflects / scatters UV rays while protecting the core layer additive from washing wear. Ultimately, a gradient structure is formed between the core layer (high antimicrobial concentration) and the sheath layer (dense UV protection layer).

[0014] Preferably, the mass ratio of caffeic acid, ethanol and ZnO nanoparticles in S1 is (1-5):(150-200):(5-15).

[0015] In some embodiments of the present invention, the ultrasonic dispersion power in S1 is 250-350W;

[0016] And / or ultrasound time is 25 to 35 minutes.

[0017] Preferably, the reflux reaction temperature in S1 is 75-85°C;

[0018] and / or the reflux reaction time is 4 to 8 hours.

[0019] Preferably, the mass ratio of dopamine hydrochloride, Tris buffer and CA-ZnO complex in S2 is (2-3):(400-600):(8-12).

[0020] In some embodiments of the present invention, the pH of the Tris buffer is 8.5.

[0021] Preferably, the stirring reaction temperature in S2 is 20-30°C;

[0022] and / or the stirring reaction time is 16 to 24 hours.

[0023] Preferably, the particle size of the CA-ZnO@PDA nanocapsules in S2 is 80 to 120 nm.

[0024] Preferably, the mass ratio of polypropylene to [BMIM]Cl in the first mixed solution S3 is (60-80):(20-40);

[0025] The amount of CA-ZnO@PDA in the second mixed solution was 6 wt % of the mass of the first mixed solution.

[0026] In some embodiments of the present invention, the temperature of the mixing, heating and stirring in S3 is 160-180° C., the rotation speed is 50-60 rpm, and the time is 20-40 min.

[0027] Preferably, the specific method of microfluidic electrospinning in S3 is: using a coaxial double-channel structure, passing the second mixed liquid through the inner channel, controlling the flow rate to 0.8 mL / h; passing the first mixed liquid through the outer channel, controlling the flow rate to 2.0 mL / h;

[0028] The spinning temperature was set at 170-190°C, the high voltage electric field was set at 13-15 kV, the receiving roller speed was set at 800 rpm, and the fiber diameter was controlled at 15-20 μm.

[0029] Preferably, the supercritical CO2 reactor processing parameters in S3 are: pressure 20 MPa, temperature 40°C, CO2 flow rate 5 L / min, and processing time 2 hours. Mineralization is incomplete below 15 MPa, while above 25 MPa may cause fiber deformation, so 20 MPa is selected.

[0030] The present invention also provides an anti-ultraviolet and antibacterial polypropylene filament, which is prepared by the above-mentioned process method.

[0031] Contains at least the following beneficial technical effects:

[0032] This invention achieves broad-spectrum antimicrobial properties by incorporating CA-ZnO@PDA nanocapsules and combining a dual bactericidal mechanism of photodynamics and metal ions. ZnO whiskers are generated in situ, forming a dense sheath structure that reflects and scatters UV light. A core-sheath gradient distribution protects the functional components from abrasion. Through innovative process design, this invention successfully addresses the limitations of traditional polypropylene fibers, such as their limited functionality, poor durability, and high process pollution. It achieves a synergistic optimization of antimicrobial, UV resistance, high strength, and environmental friendliness, making it suitable for high-value-added applications such as healthcare and outdoor protection. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 The figure is a bar graph showing the changes in the antibacterial properties of the polypropylene filaments of the embodiment and the comparative example after being irradiated with natural light for 300 hours. DETAILED DESCRIPTION

[0034] Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without creative work shall fall within the scope of protection of the present invention. The present invention will be described below with reference to specific embodiments. It should be noted that these embodiments are merely illustrative and do not limit the present invention in any way.

[0035] Example 1

[0036] This embodiment provides a process for preparing UV-resistant and antibacterial polypropylene filaments, and the preparation steps are as follows:

[0037] S1. Caffeic acid was dissolved in ethanol, and ZnO nanoparticles were then added and ultrasonically dispersed at 300W for 30 minutes. The mixture was then refluxed at 80°C for 6 hours, and then centrifuged and dried to obtain a CA-ZnO composite. The mass ratio of caffeic acid, ethanol, and ZnO nanoparticles was 3:180:10.

[0038] S2. Dopamine hydrochloride was dissolved in Tris buffer (pH 8.5), and then the CA-ZnO complex was added and stirred at 25°C for 18 h. After the reaction, the mixture was centrifuged to obtain CA-ZnO@PDA nanocapsules with a particle size of 100 nm. The mass ratio of dopamine hydrochloride, Tris buffer, and CA-ZnO complex was 2.5:500:10.

[0039] S3. Polypropylene and [BMIM] Cl were mixed in a mass ratio of 70:30 and stirred at 55 rpm for 30 min at 170 ° C to obtain a first mixed solution for standby use;

[0040] A portion of the first mixed solution was added to CA-ZnO@PDA and mixed evenly to obtain a second mixed solution; wherein the mass ratio of polypropylene, [BMIM]Cl, and CA-ZnO@PDA in the second mixed solution was 70:30:6;

[0041] The first mixed liquid and the second mixed liquid were subjected to a microfluidic electrospinning process. A coaxial double-channel structure was adopted, and the second mixed liquid was passed through the inner channel with a controlled flow rate of 0.8 mL / h; the first mixed liquid was passed through the outer channel with a controlled flow rate of 2.0 mL / h; the spinning temperature was set to 180°C, the high voltage electric field was 14 kV, the receiving roller speed was 800 rpm, and the fiber diameter was controlled at 18 μm; then the fibers were placed in a supercritical CO2 reactor with a controlled pressure of 20 MPa, a temperature of 40°C, a CO2 flow rate of 5 L / min, and a treatment time of 2 h to obtain UV-resistant and antibacterial polypropylene filaments.

[0042] Example 2

[0043] This embodiment provides a process for preparing UV-resistant and antibacterial polypropylene filaments, and the preparation steps are as follows:

[0044] S1. Caffeic acid was dissolved in ethanol, and ZnO nanoparticles were added and ultrasonically dispersed at 250W for 25 minutes. The mixture was then refluxed at 75°C for 4 hours, and then centrifuged and dried to obtain a CA-ZnO composite. The mass ratio of caffeic acid, ethanol, and ZnO nanoparticles was 1:150:5.

[0045] S2. Dopamine hydrochloride was dissolved in Tris buffer (pH 8.5), and then the CA-ZnO complex was added and stirred at 20°C for 16 hours. After the reaction, centrifugation was performed to obtain CA-ZnO@PDA nanocapsules with a particle size of 80 nm. The mass ratio of dopamine hydrochloride, Tris buffer, and CA-ZnO complex was 2:400:8.

[0046] S3. Polypropylene and [BMIM] Cl were mixed in a mass ratio of 60:20 and stirred at 50 rpm for 20 min at 160 ° C to obtain a first mixed solution for standby use;

[0047] A portion of the first mixed solution was added to CA-ZnO@PDA and mixed evenly to obtain a second mixed solution; wherein the mass ratio of polypropylene, [BMIM]Cl, and CA-ZnO@PDA in the second mixed solution was 60:20:5;

[0048] The first mixed liquid and the second mixed liquid were subjected to a microfluidic electrospinning process. A coaxial double-channel structure was adopted, and the second mixed liquid was passed through the inner channel with a controlled flow rate of 0.8 mL / h; the first mixed liquid was passed through the outer channel with a controlled flow rate of 2.0 mL / h; the spinning temperature was set to 170°C, the high voltage electric field was 13 kV, the receiving roller speed was 800 rpm, and the fiber diameter was controlled at 15 μm; then the fibers were placed in a supercritical CO2 reactor with a controlled pressure of 20 MPa, a temperature of 40°C, a CO2 flow rate of 5 L / min, and a treatment time of 2 h to obtain UV-resistant and antibacterial polypropylene filaments.

[0049] Example 3

[0050] This embodiment provides a process for preparing UV-resistant and antibacterial polypropylene filaments, and the preparation steps are as follows:

[0051] S1. Caffeic acid was dissolved in ethanol, and then ZnO nanoparticles were added and ultrasonically dispersed at 350W for 35 minutes. The mixture was then refluxed at 85°C for 8 hours, and then centrifuged and dried to obtain a CA-ZnO composite. The mass ratio of caffeic acid, ethanol, and ZnO nanoparticles was 5:200:15.

[0052] S2. Dopamine hydrochloride was dissolved in Tris buffer at pH 8.5, and then the CA-ZnO complex was added and stirred at 30°C for 24 hours. After the reaction, centrifugation was performed to obtain CA-ZnO@PDA nanocapsules with a particle size of 120 nm. The mass ratio of dopamine hydrochloride, Tris buffer, and CA-ZnO complex was 3:600:12.

[0053] S3. Polypropylene and [BMIM] Cl were mixed in a mass ratio of 80:40 and stirred at 180 ° C and 60 rpm for 40 min to obtain a first mixed solution for standby use;

[0054] A portion of the first mixed solution was added to CA-ZnO@PDA and mixed evenly to obtain a second mixed solution; wherein the mass ratio of polypropylene, [BMIM]Cl, and CA-ZnO@PDA in the second mixed solution was 80:40:8;

[0055] The first mixed liquid and the second mixed liquid were subjected to a microfluidic electrospinning process using a coaxial double-channel structure. The second mixed liquid was passed through the inner channel with a controlled flow rate of 0.8 mL / h; the first mixed liquid was passed through the outer channel with a controlled flow rate of 2.0 mL / h; the spinning temperature was set to 190°C, the high voltage electric field was 15 kV, the receiving roller speed was 800 rpm, and the fiber diameter was controlled at 20 μm; then the fibers were placed in a supercritical CO2 reactor with a controlled pressure of 20 MPa, a temperature of 40°C, a CO2 flow rate of 5 L / min, and a treatment time of 2 h to obtain UV-resistant and antibacterial polypropylene filaments.

[0056] Comparative Example 1

[0057] This comparative example provides a process for preparing UV-resistant and antibacterial polypropylene filaments, and the preparation steps are as follows:

[0058] S1. Caffeic acid was dissolved in ethanol, and then carbon nanoparticles were added and ultrasonically dispersed at 300W for 30 minutes. The mixture was then refluxed at 80°C for 6 hours, and then centrifuged and dried to obtain a CA-C complex. The mass ratio of caffeic acid, ethanol, and carbon nanoparticles was 3:180:10.

[0059] S2. Dopamine hydrochloride was dissolved in Tris buffer (pH 8.5), and then the CA-C complex was added and stirred at 25°C for 18 hours. After the reaction, centrifugation was performed to obtain CA-C@PDA nanocapsules with a particle size of 100 nm. The mass ratio of dopamine hydrochloride, Tris buffer, and CA-C complex was 2.5:500:10.

[0060] S3. Polypropylene and [BMIM] Cl were mixed in a mass ratio of 70:30 and stirred at 55 rpm for 30 min at 170 ° C to obtain a first mixed solution for standby use;

[0061] A portion of the first mixed solution was added to CA-C@PDA and mixed evenly to obtain a second mixed solution; wherein the mass ratio of polypropylene, [BMIM]Cl, and CA-C@PDA in the second mixed solution was 70:30:6;

[0062] The first mixed liquid and the second mixed liquid were subjected to a microfluidic electrospinning process. A coaxial double-channel structure was adopted, and the second mixed liquid was passed through the inner channel with a controlled flow rate of 0.8 mL / h; the first mixed liquid was passed through the outer channel with a controlled flow rate of 2.0 mL / h; the spinning temperature was set to 180°C, the high voltage electric field was 14 kV, the receiving roller speed was 800 rpm, and the fiber diameter was controlled at 18 μm; then the fibers were placed in a supercritical CO2 reactor with a controlled pressure of 20 MPa, a temperature of 40°C, a CO2 flow rate of 5 L / min, and a treatment time of 2 h to obtain UV-resistant and antibacterial polypropylene filaments.

[0063] Comparative Example 2

[0064] This comparative example provides a process for preparing UV-resistant and antibacterial polypropylene filaments, and the preparation steps are as follows:

[0065] S1. Dopamine hydrochloride was dissolved in Tris buffer (pH 8.5), and then ZnO particles were added and stirred at 25°C for 18 hours. After the reaction, the mixture was centrifuged to obtain ZnO@PDA nanocapsules with a particle size of 100 nm. The mass ratio of dopamine hydrochloride, Tris buffer, and ZnO particles was 2.5:500:10.

[0066] S2. Polypropylene and [BMIM]Cl were mixed in a mass ratio of 70:30 and stirred at 55 rpm for 30 min at 170 ° C to obtain a first mixed solution for standby use;

[0067] A portion of the first mixed solution was added with ZnO@PDA and mixed evenly to obtain a second mixed solution; wherein the mass ratio of polypropylene, [BMIM]Cl, and ZnO@PDA in the second mixed solution was 70:30:6;

[0068] The first mixed liquid and the second mixed liquid were subjected to a microfluidic electrospinning process. A coaxial double-channel structure was adopted, and the second mixed liquid was passed through the inner channel with a controlled flow rate of 0.8 mL / h; the first mixed liquid was passed through the outer channel with a controlled flow rate of 2.0 mL / h; the spinning temperature was set to 180°C, the high voltage electric field was 14 kV, the receiving roller speed was 800 rpm, and the fiber diameter was controlled at 18 μm; then the fibers were placed in a supercritical CO2 reactor with a controlled pressure of 20 MPa, a temperature of 40°C, a CO2 flow rate of 5 L / min, and a treatment time of 2 h to obtain UV-resistant and antibacterial polypropylene filaments.

[0069] Comparative Example 3

[0070] This embodiment provides a process for preparing UV-resistant and antibacterial polypropylene filaments, and the preparation steps are as follows:

[0071] S1. Caffeic acid was dissolved in ethanol, and ZnO nanoparticles were then added and ultrasonically dispersed at 300W for 30 minutes. The mixture was then refluxed at 80°C for 6 hours, and then centrifuged and dried to obtain a CA-ZnO composite. The mass ratio of caffeic acid, ethanol, and ZnO nanoparticles was 3:180:10.

[0072] S2. Dopamine hydrochloride was dissolved in Tris buffer (pH 8.5), and then the CA-ZnO complex was added and stirred at 25°C for 18 h. After the reaction, the mixture was centrifuged to obtain CA-ZnO@PDA nanocapsules with a particle size of 100 nm. The mass ratio of dopamine hydrochloride, Tris buffer, and CA-ZnO complex was 2.5:500:10.

[0073] S3. Polypropylene and [BMIM] Cl were mixed in a mass ratio of 70:30 and stirred at 55 rpm for 30 min at 170 ° C to obtain a first mixed solution for standby use;

[0074] A portion of the first mixed solution was added to CA-ZnO@PDA and mixed evenly to obtain a second mixed solution; wherein the mass ratio of polypropylene, [BMIM]Cl, and CA-ZnO@PDA in the second mixed solution was 70:30:6;

[0075] The first mixed liquid and the second mixed liquid were subjected to a microfluidic electrospinning process using a coaxial dual-channel structure. The second mixed liquid was passed through the inner channel at a controlled flow rate of 0.8 mL / h; the first mixed liquid was passed through the outer channel at a controlled flow rate of 2.0 mL / h; the spinning temperature was set at 180°C, the high voltage electric field was 14 kV, the receiving roller speed was 800 rpm, and the fiber diameter was controlled at 18 μm; and then the fiber was dried to obtain UV-resistant and antibacterial polypropylene filament.

[0076] Comparative Example 4

[0077] This comparative example provides a process for preparing UV-resistant and antibacterial polypropylene filaments, and the preparation steps are as follows:

[0078] S1. Caffeic acid was dissolved in ethanol, and ZnO nanoparticles were then added and ultrasonically dispersed at 300W for 30 minutes. The mixture was then refluxed at 80°C for 6 hours, and then centrifuged and dried to obtain a CA-ZnO composite. The mass ratio of caffeic acid, ethanol, and ZnO nanoparticles was 3:180:10.

[0079] S2. Dopamine hydrochloride was dissolved in Tris buffer (pH 8.5), and then the CA-ZnO complex was added and stirred at 25°C for 18 h. After the reaction, the mixture was centrifuged to obtain CA-ZnO@PDA nanocapsules with a particle size of 100 nm. The mass ratio of dopamine hydrochloride, Tris buffer, and CA-ZnO complex was 2.5:500:10.

[0080] S3. Polypropylene, [BMIM]Cl, and CA-ZnO@PDA were mixed in a mass ratio of 70:30:6 and spun using a microfluidic electrospinning process. The fiber diameter was controlled to be 18 μm.

[0081] Experimental Example 1

[0082] 1. The antibacterial ability of the above polypropylene filaments was tested according to GB / T 20944.3-2008. The test results are shown in Table 1.

[0083] Table 1

[0084]

[0085]

[0086] 2. The antibacterial ability of the above polypropylene filaments was tested under light, see Table 2.

[0087] The test is carried out under natural light after 300 hours of exposure to natural light. The test method refers to GB / T20944.3-2008.

[0088] Table 2

[0089]

[0090] As shown in Table 1-2, the polypropylene filaments prepared in Examples 1-4 of the present invention have obvious antibacterial ability, and the antibacterial ability does not weaken under long-term light irradiation, but the antibacterial effect on Candida albicans is enhanced; the initial antibacterial effect of Comparative Examples 1-2 is poor. After light irradiation, the antibacterial effect of Comparative Example 1 decreases significantly, and that of Comparative Example 2 decreases slightly; the antibacterial function of Comparative Examples 3-4 also decreases, indicating that under ultraviolet or visible light irradiation, CA-ZnO@PDA releases reactive oxygen species (ROS) and Zn 2+ , achieving the dual sterilization effect of "photodynamics + metal ions", and forming a gradient structure of the nuclear layer and the sheath layer to effectively deal with the side effects of excessive light.

[0091] 3. The above polypropylene filaments were tested for their UV resistance according to GB / T18830-2009 standard. The test results are shown in Table 3.

[0092] Table 3

[0093]

[0094] 4. The above polypropylene filaments were subjected to performance testing according to the testing standard GB / T 14344-2008. The test results are shown in Table 4.

[0095] Table 4

[0096] Breaking strength (cN / dtex) Elongation at break (%) Example 1 8.36 31.2 Example 2 8.31 35.1 Example 3 8.55 32.7 Comparative Example 1 7.29 29.1 Comparative Example 2 7.88 29.3 Comparative Example 3 7.21 25.1 Comparative Example 4 7.05 24.6

[0097] 5. The performance of the above polypropylene filaments was tested after exposure to light. The test results are shown in Table 5.

[0098] The test was carried out after 300 hours of natural light exposure. The test method was in accordance with GB / T 14344-2008.

[0099] Table 5

[0100]

[0101]

[0102] As shown in Tables 3-5, the polypropylene filaments prepared in the embodiments of the present invention have good UV blocking ability and UV resistance. After long-term irradiation, the UV blocking ability and physical strength do not decrease significantly; while comparative examples 1-4 all show a significant decline, and comparative example 1 does not use ZnO and suffers a large performance loss; comparative example 3 does not have ZnO whiskers to reduce strength, and comparative example 4 does not have a core layer and sheath structure, so both the initial strength and light resistance are low.

[0103] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A process for preparing UV-resistant and antibacterial polypropylene filament, characterized in that: The following steps are involved: S1. Caffeic acid was dissolved in ethanol, and then ZnO nanoparticles were added for ultrasonic dispersion. The mixture was then refluxed, centrifuged, and dried to obtain a CA-ZnO composite. S2. Dopamine hydrochloride was dissolved in Tris buffer, and then the CA-ZnO complex was added and stirred for reaction. After the reaction was completed, the CA-ZnO@PDA nanocapsules were obtained by centrifugation. S3. The polypropylene and [BMIM] Cl were mixed and heated with stirring to obtain a first mixed solution for standby use; Take part of the first mixed solution and add CA-ZnO@PDA and continue to mix evenly to obtain the second mixed solution; The first mixed liquid and the second mixed liquid are subjected to microfluidic electrospinning and then placed in a supercritical CO2 reactor for treatment to obtain UV-resistant and antibacterial polypropylene filaments.

2. The process according to claim 1, characterized in that: The mass ratio of caffeic acid, ethanol and ZnO nanoparticles in S1 is (1-5):(150-200):(5-15).

3. The process according to claim 1, characterized in that: The reflux reaction temperature in S1 is 75-85°C; and / or the reflux reaction time is 4 to 8 hours.

4. The process according to claim 1, characterized in that: The mass ratio of dopamine hydrochloride, Tris buffer and CA-ZnO complex in S2 is (2-3):(400-600):(8-12).

5. The process according to claim 1, characterized in that: The stirring reaction temperature in S2 is 20-30°C; and / or the stirring reaction time is 16 to 24 hours.

6. The process according to claim 1, characterized in that: The particle size of the CA-ZnO@PDA nanocapsules in S2 is 80-120 nm.

7. The process according to claim 1, characterized in that: The mass ratio of polypropylene to [BMIM]Cl in the first mixed solution S3 is (60-80):(20-40); The amount of CA-ZnO@PDA in the second mixed solution was 6 wt % of the mass of the first mixed solution.

8. The process according to claim 1, characterized in that: The specific method of microfluidic electrospinning in S3 is as follows: using a coaxial double-channel structure, the second mixed liquid passes through the inner channel at a controlled flow rate of 0.8 mL / h; the first mixed liquid passes through the outer channel at a controlled flow rate of 2.0 mL / h; The spinning temperature was set at 170-190°C, the high voltage electric field was set at 13-15 kV, the receiving roller speed was set at 800 rpm, and the fiber diameter was controlled at 15-20 μm.

9. The process according to claim 1, characterized in that: The processing parameters of the supercritical CO2 reactor in S3 are: pressure 20 MPa, temperature 40°C, CO2 flow rate 5 L / min, and processing time 2 h.

10. An anti-ultraviolet and antibacterial polypropylene filament, characterized in that: The product is prepared by the process according to any one of claims 1 to 9.

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