Oxolinic acid / titanium dioxide composite antibacterial fiber and preparation method thereof

Abstract

The present invention belongs to the technical field of fiber materials, and relates to an oxolinic acid / titanium dioxide composite antibacterial fiber and a preparation method thereof. After respectively preparing a core spinning solution containing oxolinic acid and a core layer substrate, and a skin spinning solution containing titanium dioxide and a skin layer substrate, the two are extruded from two needle tubes of a coaxial spinning needle, and a primary fiber is obtained through a coagulation bath. The primary fiber is post-treated to obtain the oxolinic acid / titanium dioxide composite antibacterial fiber. The present invention effectively solves the problems of insufficient stability and washability of the antibacterial agent and photodegradation in the existing antibacterial fiber through the innovative skin-core structure and the use of the composite antibacterial agent.

Description

Technical Field

[0001] The invention belongs to the technical field of fiber materials and relates to an oxolinic acid / titanium dioxide composite antibacterial fiber and a preparation method thereof. Background Art

[0002] With the increasing awareness of health and environmental protection in modern society, antimicrobial textiles have been widely used in the fields of medicine, public health and daily necessities. The main function of these textiles is to reduce the risk of bacterial transmission and cross-infection, especially in environments such as hospitals, elderly care facilities, and public places, they have become important materials for preventing bacterial transmission. However, most of the existing methods for preparing antimicrobial fibers simply combine antimicrobial agents with the fiber surface, or introduce antimicrobial agents through coating, post-treatment, etc. These methods often face the problem of insufficient stability and washability of antimicrobial agents.

[0003] Oxolinic acid, as the first generation of quinolone products, has shown a wide range of application prospects in the treatment of bacterial infections due to its broad-spectrum antibacterial properties and high efficacy. It inhibits DNA helicase and interferes with the normal replication process of bacterial DNA, showing significant antibacterial effects on a variety of Gram-negative bacteria and some Gram-positive bacteria. Patent application CN114222839A discloses that antibacterial post-treatment of fibers with oxolinic acid solution under heating and pressurization conditions can improve their antibacterial properties, but the patent does not clearly mention the specific dissolution conditions of oxolinic acid, and this method still has the problems of poor wash resistance and gradually weakened antibacterial effect. In addition, oxolinic acid will undergo photodegradation under ultraviolet light or strong light irradiation, resulting in reduced antibacterial activity, which is usually caused by ultraviolet rays inducing chemical bond breakage or generation of free radicals in oxolinic acid molecules. Therefore, when developing oxolinic acid-based fibers, it is necessary not only to solve the wash resistance problem, but also to take effective light protection measures.

[0004] Titanium dioxide (TiO 2 ) is known for its strong photocatalytic properties. It can generate electrons and holes under ultraviolet light, and then react with oxygen and water to generate active substances such as superoxide anions and hydroxyl radicals (·OH). These active substances can oxidize and decompose harmful substances such as formaldehyde, but in practical applications, the antibacterial effect of titanium dioxide often depends on ultraviolet radiation, and its fixation is poor, and it may gradually lose with use and washing.

[0005] Therefore, it is necessary to provide an antibacterial fiber with a strong and long-lasting stable antibacterial effect to overcome the problems of insufficient stability and washability of antibacterial agents in the prior art, as well as photodegradation. Summary of the invention

[0006] The purpose of the present invention is to solve the problems existing in the prior art and to provide an oxolinic acid / titanium dioxide composite antibacterial fiber and a preparation method thereof.

[0007] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0008] The invention discloses an oxolinic acid / titanium dioxide composite antibacterial fiber with a skin-core structure, comprising a skin layer substrate, a core layer substrate, oxolinic acid and titanium dioxide, wherein the oxolinic acid is located in the core layer, the titanium dioxide is located in the skin layer, and the skin layer has a channel for the oxolinic acid to pass through.

[0009] The fiber of the present invention is a long-acting antibacterial fiber. The titanium dioxide in the cortex takes effect first. The oxolinic acid in the core layer, as a small molecule compound, has a certain diffusivity. At the same time, the cortex has a channel for oxolinic acid to pass through. Therefore, the oxolinic acid in the core layer will be slowly released to provide a continuous antibacterial ability.

[0010] The fiber of the present invention combines the broad-spectrum antibacterial property of oxolinic acid with the photocatalytic property of titanium dioxide, can photoprotect oxolinic acid under ultraviolet irradiation, achieve synergistic antibacterial, and has a strong, long-lasting and stable antibacterial effect.

[0011] Titanium dioxide can be activated under ultraviolet light and produce free radicals, mainly hydroxyl radicals (·OH) and superoxide anion radicals (O 2 ·-). These free radicals have strong oxidizing properties and can react chemically with bacterial cell membranes, proteins and DNA, thereby destroying the biological structure and function of bacteria.

[0012] Oxolinic acid can bind to the topoisomerase of bacterial DNA, preventing the unwinding and repair of bacterial DNA, thereby hindering the growth and reproduction of bacteria.

[0013] The synergistic antibacterial mechanism of titanium dioxide and oxolinic acid is as follows:

[0014] ①Destroy cell membrane: The free radicals produced by titanium dioxide can attack the bacterial cell membrane, destroy its lipid and protein structure, and increase the permeability of the cell membrane. This makes it easier for oxolinic acid to enter the bacteria and enhance its effect in bacterial cells.

[0015] ② Direct DNA damage: Free radicals, especially OH, can directly attack bacterial DNA, causing DNA chain breaks and base oxidation damage. This direct damage not only makes bacterial DNA more difficult to repair, but also makes the damaged DNA almost impossible to recover when oxolinic acid hinders DNA replication and transcription.

[0016] ③ Enhance drug effects: The free radicals produced by titanium dioxide will lead to increased oxidative stress in bacteria. This environmental change may make the efficacy of oxolinic acid more significant, for example, by changing the bacterial cell metabolism or increasing the permeability of the drug.

[0017] In summary, the free radicals generated by titanium dioxide after being activated by ultraviolet light can destroy the bacterial cell membrane and promote the entry of oxolinic acid; at the same time, they can also directly attack bacterial DNA and increase DNA damage. In this way, the free radicals of oxolinic acid and titanium dioxide cooperate with each other to form a double blow, significantly improving the antibacterial effect, and can remove organic pollutants in the environment, further optimizing the use environment. In addition, the ·OH generated by titanium dioxide itself will react with formaldehyde, oxidizing it into formic acid, carbon dioxide and water, and ultimately achieving the removal of formaldehyde.

[0018] As the preferred technical solution:

[0019] As described above, the mass ratio of titanium dioxide to the skin substrate is 1:5-20, the mass ratio of oxolinic acid to the core substrate is 1:(10-30), and the diameter of the core layer is more than 1 / 2 of the diameter of the oxolinic acid / titanium dioxide composite antibacterial fiber. In this way, while ensuring continuous spinnability, the content of antibacterial agents (titanium dioxide, oxolinic acid) can be as high as possible, and the antibacterial properties of the fiber are better.

[0020] As described above, the diameter of the oxolinic acid / titanium dioxide composite antibacterial fiber is 150-500 μm. The selection of the diameter of the oxolinic acid / titanium dioxide composite antibacterial fiber should take into account the shear rate and shear viscosity of the spinning solution during extrusion to ensure that the extrusion viscosity of the skin spinning solution is less than the extrusion viscosity of the core spinning solution to avoid melt rupture at the spinning solution outlet.

[0021] The oxolinic acid / titanium dioxide composite antibacterial fiber as described above has a permanent antibacterial function, the antibacterial agent is hardly dissolved, and it will not become ineffective even after multiple frictions or washings. Compared with general antibacterial fibers, the antibacterial fiber of the present invention has a wider range of action and stronger performance in antibacterial effect. The antibacterial rate of the oxolinic acid / titanium dioxide composite antibacterial fiber against Escherichia coli and Staphylococcus aureus is more than 99%, and the antibacterial rate of the oxolinic acid / titanium dioxide composite antibacterial fiber against Escherichia coli and Staphylococcus aureus is still more than 95% after 20 washings, and the antibacterial rate of the oxolinic acid and Staphylococcus aureus is still more than 90% after 50 washings; after irradiation at a light intensity of 0.68 W / m² for 72 hours, the photodegradation rate of oxolinic acid in the oxolinic acid / titanium dioxide composite antibacterial fiber does not exceed 5%.

[0022] The present invention also provides a method for preparing an oxolinic acid / titanium dioxide composite antibacterial fiber as described in any of the above items, comprising respectively preparing a core layer spinning solution containing oxolinic acid and a core layer substrate, and a skin layer spinning solution containing titanium dioxide and a skin layer substrate, extruding the two from two needle tubes of a coaxial spinning needle, and obtaining primary fibers through a coagulation bath, and post-treating the primary fibers to obtain the oxolinic acid / titanium dioxide composite antibacterial fibers;

[0023] The viscosity of the cortical spinning solution is 143-220 mPa·s;

[0024] The skin layer substrate and the core layer substrate are both polyvinyl alcohol, and the coagulation bath is acetone or saturated sodium sulfate aqueous solution; or, the skin layer substrate and the core layer substrate are both polyurethane, and the coagulation bath is deionized water, acetic acid, ethanol or isopropanol; or, the skin layer substrate and the core layer substrate are both polyacrylonitrile, and the coagulation bath is dimethylacetamide, dimethyl sulfoxide or sodium thiocyanate; the skin layer substrate and the core layer substrate can avoid the separation problem caused by the incompatibility of the skin-core interface during fiber molding, and further consolidate the molding quality of the fiber;

[0025] Post-treatment involves soaking the nascent fiber in deionized water for 2-12 hours, freezing it in a -20°C refrigerator for 24 hours, and then freeze-drying it for 48 hours. Post-treatment ensures that oxolinic acid is firmly attached to the core layer, while titanium dioxide is stably attached to the cortex, further enhancing the antibacterial properties and durability of the fiber.

[0026] The present invention controls the viscosity of the cortical spinning solution, the type of coagulation bath, and post-treatment so that the cortical layer has a channel for oxolinic acid to pass through. The specific principle is as follows:

[0027] Rheological properties of the core and skin spinning solutions: The lower viscosity of the skin spinning solution can accelerate the solvent exchange rate, promote phase separation and maintain interfacial stability, thereby spontaneously forming a pore structure during the solidification process; these pores provide a path for the oxolinic acid in the core layer to diffuse into the skin layer;

[0028] Type of coagulation bath: The type of coagulation bath determines the formation of the cortical microporous structure by controlling the exchange rate of solvent-nonsolvent, the severity of phase separation and interface instability; fast exchange usually forms more and larger pores, providing channels for the diffusion of oxolinic acid, such as polyurethane-deionized water system and polyvinyl alcohol-acetone system; while slow exchange forms a denser cortical structure, thereby prolonging the release time of oxolinic acid to achieve a sustained-release antibacterial effect, such as polyacrylonitrile-dimethyl sulfoxide-water system and polyvinyl alcohol-saturated sodium sulfate aqueous solution system;

[0029] Post-processing steps: soaking and freeze-drying can further stabilize the structure within the cortex, ensuring the existence and long-term effectiveness of the channels. Without these post-processing steps, the cortex may collapse or densify, resulting in channel blockage.

[0030] By regulating the micropore formation of the cortex, the interface interaction of the spinning solution, and the compatibility of the skin-core interface, the present invention ensures that the cortex can form a uniform channel structure, thereby allowing oxolinic acid to slowly diffuse through the cortex and be released to the fiber surface, providing long-lasting antibacterial properties.

[0031] As the preferred technical solution:

[0032] The method as described above, the preparation process of the core layer spinning solution is: add oxolinic acid to an organic solvent (DMF, i.e., N,N-dimethylformamide), use a cell crusher to disperse it evenly, then immediately add the core layer substrate, and use a mechanical stirrer and a magnetic stirrer to stir until the core layer substrate is dissolved, and then use an ultrasonic cleaner to disperse it evenly to obtain the core layer spinning solution;

[0033] The dispersion time of the cell crusher is 15-30 minutes, and the power is 250-500W; the speed of the mechanical stirrer is 300-500rpm, the speed of the magnetic stirrer is 100-300rpm, and the stirring time is 6-12h; the dispersion time of the ultrasonic cleaning machine is 0.5-2h, and the power is 90-250W.

[0034] Oxolinic acid has low solubility, poor thermal stability, and poor compatibility with the fiber matrix, which results in that oxolinic acid cannot be evenly dispersed during the spinning process, or is easily decomposed and ineffective during the spinning process. The present invention solves this problem by making oxolinic acid evenly dispersed when configuring the core layer spinning solution.

[0035] The preparation process of the skin layer spinning solution is the same as that of the core layer spinning solution.

[0036] According to the method described above, the preparation process of the core layer spinning solution is as follows: adding the core layer substrate into an organic solvent, stirring with a magnetic stirrer until the core layer substrate is dissolved, immediately adding oxolinic acid, and dispersing it evenly with a mechanical stirrer to obtain the core layer spinning solution;

[0037] The stirring time of the magnetic stirrer is 8-24h, and the speed is 100-300rpm; the dispersion time of the mechanical stirrer is 0.5-6h, and the speed is 300-500rpm;

[0038] Alternatively, the preparation process of the core layer spinning solution is as follows: adding the core layer substrate into an organic solvent, stirring with a mechanical stirrer until the core layer substrate is dissolved, immediately adding oxolinic acid, and dispersing it evenly with a magnetic stirrer to obtain the core layer spinning solution.

[0039] In the method described above, the concentration of oxolinic acid in the core layer spinning solution is 0.01-10wt%, and the concentration of titanium dioxide in the skin layer spinning solution is 0.05-5wt%.

[0040] In the method described above, the extrusion speed is 10 m / min and the temperature of the coagulation bath is 14-50°C.

[0041] Beneficial effects:

[0042] (1) The present invention uses coaxial wet spinning technology to combine oxolinic acid and titanium dioxide to form an antibacterial fiber with a skin-core structure. This structure allows the oxolinic acid in the core layer to be slowly released, providing a continuous antibacterial ability, while the titanium dioxide in the skin layer can first contact with bacteria and exert its effect. The combination of the two achieves a synergistic antibacterial effect, significantly improves the antibacterial durability and stability, and effectively solves the problems of insufficient stability and wash resistance of antibacterial agents faced by existing antibacterial fiber preparation methods.

[0043] (2) The present invention adds titanium dioxide to the cortex and utilizes the photocatalytic properties of titanium dioxide to generate free radicals under ultraviolet irradiation. These free radicals not only have antibacterial effects, but can also photoprotect oxolinic acid and reduce the occurrence of its photodegradation. DETAILED DESCRIPTION

[0044] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall within the scope limited by the appended claims of the application equally.

[0045] The following are the test methods for the relevant performance indicators in each embodiment and comparative example:

[0046] Viscosity: Take 5 ml of the sample to be tested, add it to a 10 mL centrifuge tube, heat it in a 45 °C water bath for 30 min, and use NDJ-5S rotational viscometer (Shanghai Pingxuan Scientific Instrument Co., Ltd.) to test its viscosity value.

[0047] Antibacterial rate: Under the condition of light intensity of 0.6mW / cm², the test was carried out according to GB / T 20944.3-2008 "Evaluation of antibacterial properties of textiles" Part 3: Oscillation method. Escherichia coli and Staphylococcus aureus were selected as test strains. All strains were cultured in LB (Luria-Bertani) liquid medium at 37°C until the bacterial concentration reached 10 9 CFU / mL, then 10 9 The bacterial suspension was diluted to 10 CFU / mL. 4 CFU / mL was used to obtain the co-cultured bacterial solution; a 5 cm long sample (cut from the sample to be tested) and 3 mL of the co-cultured bacterial solution were placed in a centrifuge tube containing the co-cultured bacterial solution, and cultured at 37°C and 120 rpm for 24 h. Afterwards, 10 4The bacterial suspension of CFU / mL was evenly spread on the agar plate and cultured for 24 hours at 37°C and 65% relative humidity. After the culture was completed, the number of colonies on the plate was recorded (a control group was set up at the same time. The only difference between the control group and the test process was that no sample was added). The test process was carried out three times in parallel. Finally, the inhibition rate was calculated by the following formula: :

[0048] ;

[0049] In the formula, is the average of the colony counts on the three control plates. It is the average of the colony counts on three sample plates.

[0050] Washing: For a single wash, take 500 mg of the sample to be tested and put it into a 50 mL centrifuge tube, add 30 mL of deionized water, and centrifuge it in a TG16.5 desktop high-speed centrifuge at a speed of 5000 rpm for 10 min; replace the deionized water each time the wash is completed until the predetermined number of washes is completed, and then take out the sample and hang it to dry.

[0051] Photodegradation rate: Tested according to ISO 4892-2:2013 standard, 2g of the sample was crushed and placed in PBS buffer with a pH value of 7.4, and the initial concentration of oxolinic acid in the sample was determined by UV-Vis spectrophotometer (denoted as C 0 , unit mg / L), then, under the conditions of 25±2℃, 50±5%RH, the sample to be tested was placed under an ultraviolet light source for illumination experiment (UVB 266nm light source, light intensity of 0.68W / m²), and the sample to be tested was taken out after 72h (a control group under dark room conditions was set up at the same time to exclude the influence of non-light factors on the test results), and it was placed in PBS buffer with a pH of 7.4 again, and the residual concentration of oxolinic acid in the sample to be tested was determined by UV-visible spectrophotometer (denoted as C t , unit mg / L); finally, the photodegradation rate of oxolinic acid in the fiber was calculated according to the following formula:

[0052] Photodegradation rate = [(C 0 -C t ) / C 0 ]×100%.

[0053] Example 1

[0054] A method for preparing oxolinic acid / titanium dioxide composite antibacterial fiber, the specific steps are as follows:

[0055] (1) Preparation of materials;

[0056] Oxolinic acid;

[0057] DMF;

[0058] Core layer substrate and skin layer substrate: both are polyvinyl alcohol, the manufacturer of polyvinyl alcohol is Kuraray, the brand is PVA-117;

[0059] Titanium dioxide;

[0060] Coagulation bath: acetone, temperature 50°C;

[0061] Deionized water;

[0062] (2) preparing a core layer spinning solution and a skin layer spinning solution respectively;

[0063] The preparation process of the core layer spinning solution is as follows: add oxolinic acid to DMF, use a cell crusher to disperse it at a power of 300W for 20 minutes, immediately add the core layer substrate, and use a mechanical stirrer (the speed is set to 350rpm) and a magnetic stirrer (the speed is set to 150rpm) to stir for 10 hours, and then use an ultrasonic cleaner to disperse it at a power of 200W for 1 hour to obtain the core layer spinning solution; wherein, the mass ratio of oxolinic acid to the core layer substrate is 1:20, and the concentration of oxolinic acid in the core layer spinning solution is 4wt%;

[0064] The cortex spinning solution is prepared from a cortex substrate, titanium dioxide and DMF, the mass ratio of titanium dioxide to the cortex substrate is 1:15, the concentration of titanium dioxide in the cortex spinning solution is 3wt%, and the viscosity of the cortex spinning solution is 198.1mPa·s;

[0065] (3) Preparation of oxolinic acid / titanium dioxide composite antibacterial fiber;

[0066] The core spinning solution and the skin spinning solution are extruded from the two needle tubes of the coaxial spinning needle at a speed of 10m / min. After the primary fiber is obtained through a coagulation bath, the primary fiber is first soaked in deionized water for 4h, and then placed in a low-temperature refrigerator at -20℃ and frozen for 24h. The primary fiber is then freeze-dried for 48h to obtain the oxolinic acid / titanium dioxide composite antibacterial fiber.

[0067] The finally prepared oxolinic acid / titanium dioxide composite antibacterial fiber has a skin-core structure, consisting of a skin layer substrate, a core layer substrate, oxolinic acid and titanium dioxide, wherein the oxolinic acid is located in the core layer, and the titanium dioxide is located in the skin layer, and the skin layer has a channel for the oxolinic acid to pass through. The diameter of the oxolinic acid / titanium dioxide composite antibacterial fiber is 430 μm, and the diameter of the core layer is 225 μm.

[0068] The antibacterial rate of the oxolinic acid / titanium dioxide composite antibacterial fiber against Escherichia coli was 99.77%, and the antibacterial rate against Staphylococcus aureus was 99.53%; after 20 washings, the antibacterial rate of the oxolinic acid / titanium dioxide composite antibacterial fiber against Escherichia coli was 96.75%, and the antibacterial rate against Staphylococcus aureus was 95.37%; after 50 washings, the antibacterial rate of the oxolinic acid / titanium dioxide composite antibacterial fiber against Escherichia coli was 90.77%, and the antibacterial rate against Staphylococcus aureus was 90.23%; the photodegradation rate of oxolinic acid in the oxolinic acid / titanium dioxide composite antibacterial fiber was 1%.

[0069] Comparative Example 1

[0070] A method for preparing a fiber, the difference from Example 1 is that oxolinic acid is replaced by an equal mass of titanium dioxide.

[0071] The final fiber had an antibacterial rate of 51.23% against Escherichia coli and 42.52% against Staphylococcus aureus; after 20 washings, the antibacterial rate of the fiber against Escherichia coli was 34.61% and 33.59% against Staphylococcus aureus; after 50 washings, the antibacterial rate of the fiber against Escherichia coli was 26.45% and 24.16% against Staphylococcus aureus.

[0072] Compared with Example 1, the antibacterial effect and long-term stability of the fiber are significantly reduced in Comparative Example 1. This is because after replacing oxolinic acid with an equal mass of titanium dioxide in Comparative Example 1, the synergistic mechanism is lost, and the antibacterial effect is only based on titanium dioxide photocatalysis, which is limited by light and has a single mode of action, and lacks the supplement of sustained release of antibacterial ingredients. In addition, titanium dioxide is easily shed when washed with water, which leads to poor antibacterial effect and long-term stability.

[0073] Comparative Example 2

[0074] A method for preparing a fiber, the difference from Example 1 is that titanium dioxide is replaced by an equal mass of oxolinic acid.

[0075] The final fiber had an antibacterial rate of 70.17% against Escherichia coli and 50.23% against Staphylococcus aureus; the photodegradation rate of oxolinic acid in the fiber was 35%.

[0076] Compared with Example 1, the antibacterial effect of the fiber in Comparative Example 2 is significantly reduced, and the photodegradation rate of oxolinic acid in the fiber is significantly increased. This is because after titanium dioxide is replaced with an equal mass of oxolinic acid in Comparative Example 2, the synergistic antibacterial mechanism is lost, resulting in a poor antibacterial effect; at the same time, oxolinic acid itself has the problem of photodegradation under ultraviolet light or strong light irradiation, and the oxolinic acid in the cortex is easily lost, and the oxolinic acid in the core layer will also be lost due to the lack of the light protection effect of titanium dioxide.

[0077] Comparative Example 3

[0078] A method for preparing a fiber, which differs from Example 1 only in that: when preparing the cortex spinning solution, the mass ratio of titanium dioxide to the cortex substrate is 1:30, the concentration of titanium dioxide in the cortex spinning solution is 10wt%, and the viscosity of the cortex spinning solution is 293mPa·s.

[0079] The final fiber had an antibacterial rate of 85.68% against Escherichia coli and 84.27% against Staphylococcus aureus; after 20 washings, the antibacterial rate of the fiber against Escherichia coli was 75.36% and 74.12% against Staphylococcus aureus; after 50 washings, the antibacterial rate of the fiber against Escherichia coli was 61.41% and 60.87% against Staphylococcus aureus.

[0080] Compared with Example 1, the antibacterial effect of the fiber in Comparative Example 3 is significantly reduced as well as its long-term stability. This is because the concentration of titanium dioxide in the cortex spinning solution is too high, resulting in excessively high viscosity of the cortex spinning solution, hindering solvent exchange and phase separation, making it difficult for the coagulation bath to normally regulate the formation of the microporous structure, and ultimately resulting in the inability of the cortex to form a channel for oxolinic acid to pass through, making it difficult for oxolinic acid to diffuse to the fiber surface to exert its antibacterial effect. In addition, titanium dioxide is easily shed when washed with water, which results in a combined deterioration in the antibacterial effect and long-term stability.

[0081] Comparative Example 4

[0082] A method for preparing a fiber, which is different from Example 1 only in that the coagulation bath acetone is replaced by a mixture of ethanol and deionized water at a temperature of 50° C. and a volume ratio of 7:3.

[0083] The final fiber had an antibacterial rate of 68.23% against Escherichia coli and 65.56% against Staphylococcus aureus; after 20 washings, the antibacterial rate of the fiber against Escherichia coli was 50.75%, and the antibacterial rate against Staphylococcus aureus was 46.27%; after 50 washings, the antibacterial rate of the fiber against Escherichia coli was 30.46%, and the antibacterial rate against Staphylococcus aureus was 28.76%.

[0084] Compared with Example 1, the antibacterial effect and long-term stability of the fiber in Comparative Example 4 are significantly reduced, and the photodegradation rate of oxolinic acid in the fiber is significantly increased. This is because when the coagulation bath is replaced with a mixture of ethanol and deionized water, the solvent-non-solvent exchange rate is relatively slow, making it difficult for the coagulation bath to normally regulate the formation of the microporous structure, and ultimately resulting in the inability of the cortex to form a channel for oxolinic acid to pass through, making it difficult for oxolinic acid to diffuse to the fiber surface to exert its antibacterial effect. In addition, titanium dioxide is easily shed when washed with water, which leads to a comprehensive deterioration of the antibacterial effect and long-term stability.

[0085] Comparative Example 5

[0086] A method for preparing a fiber, which differs from Example 1 only in that: the process of step (3) is: extruding the core layer spinning solution and the skin layer spinning solution from the two needle tubes of the coaxial spinning needle at a speed of 10m / min, and obtaining the fiber through a coagulation bath.

[0087] The final fiber had an antibacterial rate of 72.14% against Escherichia coli and 70.23% against Staphylococcus aureus; after 20 washings, the antibacterial rate of the fiber against Escherichia coli was 55.76%, and the antibacterial rate against Staphylococcus aureus was 50.37%; after 50 washings, the antibacterial rate of the fiber against Escherichia coli was 40.88%, and the antibacterial rate against Staphylococcus aureus was 38.23%.

[0088] Compared with Example 1, the antibacterial effect of the fiber in Comparative Example 5 is significantly reduced as well as its long-term stability. This is because the post-treatment operation is omitted, resulting in the lack of further stabilization measures for the internal structure of the cortex after spinning and coagulation bath treatment, which leads to collapse or densification, resulting in blockage of the originally formed diffusion channel for oxolinic acid, making it difficult for oxolinic acid to reach the fiber surface smoothly to exert its antibacterial effect. In addition, titanium dioxide is easily shed when washed with water, which leads to the deterioration of the antibacterial effect and long-term stability.

[0089] Example 2

[0090] A method for preparing oxolinic acid / titanium dioxide composite antibacterial fiber, which is different from Example 1 only in that the coagulation bath acetone is replaced by a saturated sodium sulfate aqueous solution at a temperature of 50°C.

[0091] The final antibacterial rate of the oxolinic acid / titanium dioxide composite antibacterial fiber against Escherichia coli was 99.82%, and the antibacterial rate against Staphylococcus aureus was 99.67%; after 20 washings, the antibacterial rate of the oxolinic acid / titanium dioxide composite antibacterial fiber against Escherichia coli was 96.35%, and the antibacterial rate against Staphylococcus aureus was 95.27%; after 50 washings, the antibacterial rate of the oxolinic acid / titanium dioxide composite antibacterial fiber against Escherichia coli was 90.18%, and the antibacterial rate against Staphylococcus aureus was 92.75%; the photodegradation rate of oxolinic acid in the oxolinic acid / titanium dioxide composite antibacterial fiber was 3.94%.

[0092] Example 3

[0093] A method for preparing oxolinic acid / titanium dioxide composite antibacterial fiber, the specific steps are as follows:

[0094] (1) Preparation of materials;

[0095] Oxolinic acid;

[0096] DMF;

[0097] Core layer substrate and skin layer substrate: both are polyurethane, the manufacturer of polyurethane is BASF, the brand is 1185A;

[0098] Titanium dioxide;

[0099] Coagulation bath: deionized water, temperature 14°C;

[0100] Deionized water;

[0101] (2) preparing a core layer spinning solution and a skin layer spinning solution respectively;

[0102] The preparation process of the core layer spinning solution is as follows: add oxolinic acid to DMF, use a cell crusher to disperse it at a power of 450W for 15 minutes, then immediately add the core layer substrate, and use a mechanical stirrer (the speed is set to 370rpm) and a magnetic stirrer (the speed is set to 200rpm) to stir for 8 hours, and then use an ultrasonic cleaner to disperse it at a power of 120W for 0.8 hours to obtain the core layer spinning solution; wherein, the mass ratio of oxolinic acid to the core layer substrate is 1:14, and the concentration of oxolinic acid in the core layer spinning solution is 1wt%;

[0103] The cortex spinning solution is prepared from a cortex substrate, titanium dioxide and DMF, the mass ratio of titanium dioxide to the cortex substrate is 1:8, the concentration of titanium dioxide in the cortex spinning solution is 0.1wt%, and the viscosity of the cortex spinning solution is 157.5mPa·s;

[0104] (3) Preparation of oxolinic acid / titanium dioxide composite antibacterial fiber;

[0105] The core layer spinning solution and the skin layer spinning solution are extruded from the two needle tubes of the coaxial spinning needle at a speed of 10m / min. After the primary fiber is obtained through a coagulation bath, the primary fiber is first soaked in deionized water for 2h, and then placed in a low-temperature refrigerator at -20℃ and frozen for 24h. The primary fiber is then freeze-dried for 48h to obtain the oxolinic acid / titanium dioxide composite antibacterial fiber.

[0106] The finally prepared oxolinic acid / titanium dioxide composite antibacterial fiber has a skin-core structure, consisting of a skin layer substrate, a core layer substrate, oxolinic acid and titanium dioxide, wherein the oxolinic acid is located in the core layer, and the titanium dioxide is located in the skin layer, and the skin layer has a channel for the oxolinic acid to pass through. The diameter of the oxolinic acid / titanium dioxide composite antibacterial fiber is 200 μm, and the diameter of the core layer is 120 μm.

[0107] The antibacterial rate of the oxolinic acid / titanium dioxide composite antibacterial fiber against Escherichia coli was 99.54%, and the antibacterial rate against Staphylococcus aureus was 99.47%; after 20 washings, the antibacterial rate of the oxolinic acid / titanium dioxide composite antibacterial fiber against Escherichia coli was 97.84%, and the antibacterial rate against Staphylococcus aureus was 96.24%; after 50 washings, the antibacterial rate of the oxolinic acid / titanium dioxide composite antibacterial fiber against Escherichia coli was 93.54%, and the antibacterial rate against Staphylococcus aureus was 92.67%; the photodegradation rate of oxolinic acid in the oxolinic acid / titanium dioxide composite antibacterial fiber was 3%.

[0108] Example 4

[0109] A method for preparing oxolinic acid / titanium dioxide composite antibacterial fiber, the specific steps are as follows:

[0110] (1) Preparation of materials;

[0111] Oxolinic acid;

[0112] DMF;

[0113] Core layer substrate and skin layer substrate: both are polyurethane, the manufacturer of polyurethane is BASF, the brand is 1185A;

[0114] Titanium dioxide;

[0115] Coagulation bath: acetic acid, temperature 37°C;

[0116] Deionized water;

[0117] (2) preparing a core layer spinning solution and a skin layer spinning solution respectively;

[0118] The preparation process of the core layer spinning solution is as follows: add oxolinic acid to DMF, use a cell crusher to disperse it at a power of 250W for 15 minutes, immediately add the core layer substrate, and use a mechanical stirrer (the speed is set to 300rpm) and a magnetic stirrer (the speed is set to 100rpm) to stir for 6 hours, and then use an ultrasonic cleaner to disperse it at a power of 90W for 0.5 hours to obtain the core layer spinning solution; wherein, the mass ratio of oxolinic acid to the core layer substrate is 1:30, and the concentration of oxolinic acid in the core layer spinning solution is 0.01wt%;

[0119] The cortex spinning solution is prepared from a cortex substrate, titanium dioxide and DMF, the mass ratio of titanium dioxide to the cortex substrate is 1:20, the concentration of titanium dioxide in the cortex spinning solution is 0.05wt%, and the viscosity of the cortex spinning solution is 143mPa·s;

[0120] (3) Preparation of oxolinic acid / titanium dioxide composite antibacterial fiber;

[0121] The core layer spinning solution and the skin layer spinning solution are extruded from the two needle tubes of the coaxial spinning needle at a speed of 10m / min. After the primary fiber is obtained through a coagulation bath, the primary fiber is first soaked in deionized water for 8h, and then placed in a low-temperature refrigerator at -20℃ and frozen for 24h. The primary fiber is then freeze-dried for 48h to obtain the oxolinic acid / titanium dioxide composite antibacterial fiber.

[0122] The finally prepared oxolinic acid / titanium dioxide composite antibacterial fiber has a skin-core structure, consisting of a skin layer substrate, a core layer substrate, oxolinic acid and titanium dioxide, wherein the oxolinic acid is located in the core layer, and the titanium dioxide is located in the skin layer, and the skin layer has a channel for the oxolinic acid to pass through, and the diameter of the oxolinic acid / titanium dioxide composite antibacterial fiber is 500 μm, and the diameter of the core layer is 300 μm;

[0123] The antibacterial rate of the oxolinic acid / titanium dioxide composite antibacterial fiber against Escherichia coli was 99.99%, and the antibacterial rate against Staphylococcus aureus was 99.98%; after 20 washings, the antibacterial rate of the oxolinic acid / titanium dioxide composite antibacterial fiber against Escherichia coli was 97.43%, and the antibacterial rate against Staphylococcus aureus was 96.99%; after 50 washings, the antibacterial rate of the oxolinic acid / titanium dioxide composite antibacterial fiber against Escherichia coli was 94.99%, and the antibacterial rate against Staphylococcus aureus was 94.21%; the photodegradation rate of oxolinic acid in the oxolinic acid / titanium dioxide composite antibacterial fiber was 5%.

[0124] Example 5

[0125] A method for preparing oxolinic acid / titanium dioxide composite antibacterial fiber, which is different from Example 4 only in that the acetic acid in the coagulation bath is replaced by ethanol at a temperature of 27°C.

[0126] The final antibacterial rate of the oxolinic acid / titanium dioxide composite antibacterial fiber against Escherichia coli was 99.75%, and the antibacterial rate against Staphylococcus aureus was 99.43%; after 20 washings, the antibacterial rate of the oxolinic acid / titanium dioxide composite antibacterial fiber against Escherichia coli was 97.57%, and the antibacterial rate against Staphylococcus aureus was 96.14%; after 50 washings, the antibacterial rate of the oxolinic acid / titanium dioxide composite antibacterial fiber against Escherichia coli was 92.55%, and the antibacterial rate against Staphylococcus aureus was 91.67%; the photodegradation rate of oxolinic acid in the oxolinic acid / titanium dioxide composite antibacterial fiber was 2.87%.

[0127] Example 6

[0128] A method for preparing oxolinic acid / titanium dioxide composite antibacterial fiber, which is different from Example 4 only in that the acetic acid in the coagulation bath is replaced by isopropanol at a temperature of 27°C.

[0129] The final antibacterial rate of the oxolinic acid / titanium dioxide composite antibacterial fiber against Escherichia coli was 99.24%, and the antibacterial rate against Staphylococcus aureus was 99.11%; after 20 washings, the antibacterial rate of the oxolinic acid / titanium dioxide composite antibacterial fiber against Escherichia coli was 97.53%, and the antibacterial rate against Staphylococcus aureus was 95.32%; after 50 washings, the antibacterial rate of the oxolinic acid / titanium dioxide composite antibacterial fiber against Escherichia coli was 92.12%, and the antibacterial rate against Staphylococcus aureus was 91.25%; the photodegradation rate of oxolinic acid in the oxolinic acid / titanium dioxide composite antibacterial fiber was 1.57%.

[0130] Example 7

[0131] A method for preparing oxolinic acid / titanium dioxide composite antibacterial fiber, the specific steps are as follows:

[0132] (1) Preparation of materials;

[0133] Oxolinic acid;

[0134] DMF;

[0135] The core layer substrate and the skin layer substrate are both made of polyacrylonitrile, the manufacturer of which is Shanghai MacLean Biochemical Technology Co., Ltd., with the brand name P823208;

[0136] Titanium dioxide;

[0137] Coagulation bath: dimethylacetamide, temperature 27°C;

[0138] Deionized water;

[0139] (2) preparing a core layer spinning solution and a skin layer spinning solution respectively;

[0140] The preparation process of the core layer spinning solution is as follows: add oxolinic acid to DMF, use a cell crusher to disperse it at a power of 500W for 30 minutes, immediately add the core layer substrate, and use a mechanical stirrer (the speed is set to 500rpm) and a magnetic stirrer (the speed is set to 300rpm) to stir for 12 hours, and then use an ultrasonic cleaner to disperse it at a power of 250W for 2 hours to obtain the core layer spinning solution; wherein, the mass ratio of oxolinic acid to the core layer substrate is 1:10, and the concentration of oxolinic acid in the core layer spinning solution is 10wt%;

[0141] The cortex spinning solution is prepared from a cortex substrate, titanium dioxide and DMF, the mass ratio of titanium dioxide to the cortex substrate is 1:5, the concentration of titanium dioxide in the cortex spinning solution is 5wt%, and the viscosity of the cortex spinning solution is 220mPa·s;

[0142] (3) Preparation of oxolinic acid / titanium dioxide composite antibacterial fiber;

[0143] The core layer spinning solution and the skin layer spinning solution are extruded from the two needle tubes of the coaxial spinning needle at a speed of 10m / min. After the primary fiber is obtained through a coagulation bath, the primary fiber is first soaked in deionized water for 10 hours, and then the primary fiber is placed in a low-temperature refrigerator at -20°C and frozen for 24 hours. The primary fiber is then freeze-dried for 48 hours to obtain the oxolinic acid / titanium dioxide composite antibacterial fiber.

[0144] The finally prepared oxolinic acid / titanium dioxide composite antibacterial fiber has a skin-core structure, consisting of a skin layer substrate, a core layer substrate, oxolinic acid and titanium dioxide, wherein the oxolinic acid is located in the core layer, and the titanium dioxide is located in the skin layer, and the skin layer has a channel for the oxolinic acid to pass through. The diameter of the oxolinic acid / titanium dioxide composite antibacterial fiber is 150 μm, and the diameter of the core layer is 80 μm.

[0145] The antibacterial rate of the oxolinic acid / titanium dioxide composite antibacterial fiber against Escherichia coli was 99.86%, and the antibacterial rate against Staphylococcus aureus was 99.65%; after 20 washings, the antibacterial rate of the oxolinic acid / titanium dioxide composite antibacterial fiber against Escherichia coli was 95.64%, and the antibacterial rate against Staphylococcus aureus was 95.66%; after 50 washings, the antibacterial rate of the oxolinic acid / titanium dioxide composite antibacterial fiber against Escherichia coli was 92.86%, and the antibacterial rate against Staphylococcus aureus was 92.06%; the photodegradation rate of oxolinic acid in the oxolinic acid / titanium dioxide composite antibacterial fiber was 2.7%.

[0146] Example 8

[0147] A method for preparing oxolinic acid / titanium dioxide composite antibacterial fiber, the specific steps are as follows:

[0148] (1) Preparation of materials;

[0149] Oxolinic acid;

[0150] DMF;

[0151] The core layer substrate and the skin layer substrate are both made of polyacrylonitrile, the manufacturer of which is Shanghai MacLean Biochemical Technology Co., Ltd., with the brand name P823208;

[0152] Titanium dioxide;

[0153] Coagulation bath: dimethyl sulfoxide, temperature 25°C;

[0154] Deionized water;

[0155] (2) preparing a core layer spinning solution and a skin layer spinning solution respectively;

[0156] The preparation process of the core layer spinning solution is as follows: add oxolinic acid to DMF, use a cell crusher to disperse it at a power of 500W for 25 minutes, then immediately add the core layer substrate, and use a mechanical stirrer (the speed is set to 420rpm) and a magnetic stirrer (the speed is set to 270rpm) to stir for 9 hours, and then use an ultrasonic cleaner to disperse it at a power of 150W for 1.5 hours to obtain the core layer spinning solution; wherein, the mass ratio of oxolinic acid to the core layer substrate is 1:18, and the concentration of oxolinic acid in the core layer spinning solution is 7wt%;

[0157] The cortex spinning solution is prepared from a cortex substrate, titanium dioxide and DMF, the mass ratio of titanium dioxide to the cortex substrate is 1:10, the concentration of titanium dioxide in the cortex spinning solution is 1wt%, and the viscosity of the cortex spinning solution is 173.4mPa·s;

[0158] (3) Preparation of oxolinic acid / titanium dioxide composite antibacterial fiber;

[0159] The core layer spinning solution and the skin layer spinning solution are extruded from the two needle tubes of the coaxial spinning needle at a speed of 10m / min. After the primary fiber is obtained through a coagulation bath, the primary fiber is first soaked in deionized water for 12h, and then placed in a low-temperature refrigerator at -20℃ and frozen for 24h. The primary fiber is then freeze-dried for 48h to obtain the oxolinic acid / titanium dioxide composite antibacterial fiber.

[0160] The finally prepared oxolinic acid / titanium dioxide composite antibacterial fiber has a skin-core structure, consisting of a skin layer substrate, a core layer substrate, oxolinic acid and titanium dioxide, wherein the oxolinic acid is located in the core layer, and the titanium dioxide is located in the skin layer, and the skin layer has a channel for the oxolinic acid to pass through. The diameter of the oxolinic acid / titanium dioxide composite antibacterial fiber is 350 μm, and the diameter of the core layer is 185 μm.

[0161] The antibacterial rate of the oxolinic acid / titanium dioxide composite antibacterial fiber against Escherichia coli was 99.73%, and the antibacterial rate against Staphylococcus aureus was 99.58%; after 20 washings, the antibacterial rate of the oxolinic acid / titanium dioxide composite antibacterial fiber against Escherichia coli was 98.44%, and the antibacterial rate against Staphylococcus aureus was 97.72%; after 50 washings, the antibacterial rate of the oxolinic acid / titanium dioxide composite antibacterial fiber against Escherichia coli was 91.73%, and the antibacterial rate against Staphylococcus aureus was 91.12%; the photodegradation rate of oxolinic acid in the oxolinic acid / titanium dioxide composite antibacterial fiber was 4.2%.

[0162] Example 9

[0163] A method for preparing oxolinic acid / titanium dioxide composite antibacterial fiber, which is different from Example 8 only in that the coagulation bath dimethyl sulfoxide is replaced by sodium thiocyanate at a temperature of 25°C.

[0164] The final antibacterial rate of the oxolinic acid / titanium dioxide composite antibacterial fiber against Escherichia coli was 99.45%, and the antibacterial rate against Staphylococcus aureus was 99.21%; after 20 washings, the antibacterial rate of the oxolinic acid / titanium dioxide composite antibacterial fiber against Escherichia coli was 97.56%, and the antibacterial rate against Staphylococcus aureus was 95.78%; after 50 washings, the antibacterial rate of the oxolinic acid / titanium dioxide composite antibacterial fiber against Escherichia coli was 93.24%, and the antibacterial rate against Staphylococcus aureus was 92.45%; the photodegradation rate of oxolinic acid in the oxolinic acid / titanium dioxide composite antibacterial fiber was 4.23%.

Claims

1. An oxolinic acid / titanium dioxide composite antibacterial fiber, characterized in that: It has a skin-core structure, including a skin layer substrate, a core layer substrate, oxolinic acid and titanium dioxide, wherein the oxolinic acid is located in the core layer, the titanium dioxide is located in the skin layer, and the skin layer has a channel for the oxolinic acid to pass through; The preparation method of the oxolinic acid / titanium dioxide composite antibacterial fiber comprises: respectively preparing a core layer spinning solution containing oxolinic acid and a core layer substrate, and a skin layer spinning solution containing titanium dioxide and a skin layer substrate, extruding the two from two needle tubes of a coaxial spinning needle, and obtaining primary fibers through a coagulation bath, and post-treating the primary fibers to obtain the oxolinic acid / titanium dioxide composite antibacterial fiber; The viscosity of the cortical spinning solution is 143-220 mPa·s; The skin layer substrate and the core layer substrate are both polyvinyl alcohol, and the coagulation bath is acetone or saturated sodium sulfate aqueous solution; or, the skin layer substrate and the core layer substrate are both polyurethane, and the coagulation bath is deionized water, acetic acid, ethanol or isopropanol; or, the skin layer substrate and the core layer substrate are both polyacrylonitrile, and the coagulation bath is dimethylacetamide, dimethyl sulfoxide or sodium thiocyanate; The post-treatment is to soak the raw fiber in deionized water for 2-12 hours, then put it in a low-temperature refrigerator at -20°C for 24 hours, and then freeze-dry it for 48 hours.

2. The oxolinic acid / titanium dioxide composite antibacterial fiber according to claim 1, characterized in that: The mass ratio of titanium dioxide to the skin substrate is 1:5-20, the mass ratio of oxolinic acid to the core substrate is 1:(10-30), and the diameter of the core layer is more than 1 / 2 of the diameter of the oxolinic acid / titanium dioxide composite antibacterial fiber.

3. The oxolinic acid / titanium dioxide composite antibacterial fiber according to claim 2, characterized in that: The diameter of the oxolinic acid / titanium dioxide composite antibacterial fiber is 150-500 μm.

4. The oxolinic acid / titanium dioxide composite antibacterial fiber according to any one of claims 1 to 3, characterized in that: The antibacterial rates of the oxolinic acid / titanium dioxide composite antibacterial fiber against Escherichia coli and Staphylococcus aureus were both above 99%. After 20 washes, the antibacterial rates against Escherichia coli and Staphylococcus aureus were still above 95%, and after 50 washes, the antibacterial rates against Escherichia coli and Staphylococcus aureus were still above 90%. 2 After irradiation for 72 hours under a light intensity of , the photodegradation rate of oxolinic acid in the oxolinic acid / titanium dioxide composite antibacterial fiber did not exceed 5%.

5. A method for preparing an oxolinic acid / titanium dioxide composite antibacterial fiber as claimed in any one of claims 1 to 4, characterized in that: A core layer spinning solution containing oxolinic acid and a core layer substrate and a skin layer spinning solution containing titanium dioxide and a skin layer substrate are respectively prepared, and the two are extruded from two needle tubes of a coaxial spinning needle head, and primary fibers are obtained through a coagulation bath, and the primary fibers are post-treated to obtain oxolinic acid / titanium dioxide composite antibacterial fibers; The viscosity of the cortical spinning solution is 143-220 mPa·s; The skin layer substrate and the core layer substrate are both polyvinyl alcohol, and the coagulation bath is acetone or saturated sodium sulfate aqueous solution; or, the skin layer substrate and the core layer substrate are both polyurethane, and the coagulation bath is deionized water, acetic acid, ethanol or isopropanol; or, the skin layer substrate and the core layer substrate are both polyacrylonitrile, and the coagulation bath is dimethylacetamide, dimethyl sulfoxide or sodium thiocyanate; The post-treatment is to soak the raw fiber in deionized water for 2-12 hours, then put it in a low-temperature refrigerator at -20°C for 24 hours, and then freeze-dry it for 48 hours.

6. The method according to claim 5, characterized in that The preparation process of the core layer spinning solution is as follows: oxolinic acid is added to an organic solvent, and after being evenly dispersed by a cell crusher, a core layer substrate is immediately added, and a mechanical stirrer and a magnetic stirrer are used to stir until the core layer substrate is dissolved, and then an ultrasonic cleaner is used to evenly disperse the core layer spinning solution; The dispersion time of the cell crusher is 15-30 minutes, and the power is 250-500W; the speed of the mechanical stirrer is 300-500rpm, the speed of the magnetic stirrer is 100-300rpm, and the stirring time is 6-12h; the dispersion time of the ultrasonic cleaning machine is 0.5-2h, and the power is 90-250W.

7. The method according to claim 5, characterized in that The preparation process of the core layer spinning solution is as follows: adding the core layer substrate into an organic solvent, stirring with a magnetic stirrer until the core layer substrate is dissolved, immediately adding oxolinic acid, and dispersing it evenly with a mechanical stirrer to obtain the core layer spinning solution; The stirring time of the magnetic stirrer is 8-24h, and the speed is 100-300rpm; the dispersion time of the mechanical stirrer is 0.5-6h, and the speed is 300-500rpm.

8. The method according to claim 5, characterized in that The concentration of oxolinic acid in the core layer spinning solution is 0.01-10wt%, and the concentration of titanium dioxide in the skin layer spinning solution is 0.05-5wt%.

9. The method according to claim 5, characterized in that The extrusion speed was 10 m / min and the temperature of the coagulation bath was 14-50°C.