A photocatalyst fiber with a skin-core structure and a preparation method thereof

Abstract

The present invention belongs to the technical field of functional fibers, and discloses a photocatalyst fiber with a skin-core structure and a preparation method thereof. The photocatalyst fiber with the skin-core structure includes a skin layer and a core layer. The skin layer includes a synthetic resin and a photocatalyst. Among them, the synthetic resin is pulverized by air flow and then mixed and granulated with the photocatalyst for spinning. The core layer contains a light stabilizer. In the present invention, the synthetic resin is micronized by air flow pulverization, which can be more evenly mixed with the photocatalyst, thereby improving the uniformity of the distribution of the photocatalyst in the skin layer, improving the mechanical properties and photocatalytic effect of the photocatalyst fiber. At the same time, the core layer of the photocatalyst fiber contains a light stabilizer, which can avoid the problem of self-photolysis of the fiber while the photocatalyst in the skin layer undergoes a photocatalytic reaction, further ensuring the mechanical properties of the photocatalyst fiber and making the photocatalyst fiber have better durability.

Description

Technical Field

[0001] The present invention belongs to the technical field of functional fibers, and specifically relates to a photocatalyst fiber with a skin-core structure and a preparation method thereof. Background Art

[0002] A photocatalyst fiber is a fiber with photocatalytic function. Generally, its manufacturing method is to immerse the fiber or yarn in the photocatalyst in sol state, or after the fiber is woven into a fabric, the fiber is wrapped and covered by screen printing or gravure printing. The photocatalytic effect is very good at the beginning, but due to the desorption of the adhesive after washing, the photocatalyst mixed with the adhesive will separate, so after several washes, its functionality will decrease significantly.

[0003] For the functional fiber prepared by mixing photocatalyst particles and polymer by solution blending or melt blending, the photocatalyst particles inside the fiber cannot be irradiated by light and cannot play a role, and will also damage the fiber continuity and affect the mechanical properties. Moreover, due to the strong oxidation ability of the photocatalyst, the macromolecular chain segments of the fiber will be partially broken, thus increasing the number of molecular chain end groups in the amorphous region of the fiber and weakening the supramolecular structure of the fiber. No matter what method is used to attach the photocatalyst to the fiber surface or spin it into the fiber interior, there is a problem that while the photocatalyst plays a role, the fiber material deteriorates, ultimately leading to a decrease in the macroscopic mechanical properties of the fiber. Dong Yongchun et al. adopted the skin-core spinning method in "A Preparation Method of Functionalized Photocatalyst Fiber" to prepare skin-core type functionalized photocatalyst PET, whose various properties are superior to those of ordinary PET photocatalyst fibers, but during long-term use, there is still a problem that while the photocatalyst plays a role, the core layer PET is gradually decomposed, resulting in fiber aging, performance degradation, and shortened service life.

[0004] It can be seen that in the prior art, for the photocatalyst fiber filaments obtained by photocatalyst coating or impregnation, during use, due to the easy detachment of the photocatalyst by washing, there is a problem that its functionality such as stain resistance or antibacterial and deodorizing properties decreases significantly with the increase in the number of washes. And if functional ions are incorporated during the masterbatch processing, since it is difficult for functional particles at the micro-nano scale to be uniformly dispersed in resin pellets or chips, during the fiber manufacturing process, excessive local particle agglomeration content is likely to cause problems such as fiber breakage and fuzzing. At the same time, when the photocatalyst plays a role under light irradiation, it will also cause problems of fiber performance deterioration and mechanical property decline.

[0005] In view of this, the present invention is specifically proposed. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art and provide a photocatalyst fiber with a skin-core structure and a preparation method thereof. The photocatalyst fiber can fully exert its photocatalytic effect, and at the same time will not be photocatalytically decomposed itself, and has good durability.

[0007] To solve the above technical problems, the basic concept of the technical solution adopted by the present invention is:

[0008] A photocatalyst fiber with a skin-core structure includes a skin layer and a core layer. The skin layer includes a synthetic resin and a photocatalyst. Among them, the synthetic resin is pulverized by air flow and then mixed with the photocatalyst for granulation for spinning; the core layer contains a light stabilizer.

[0009] In the above solution, the photocatalyst fiber has a skin-core structure, and the photocatalyst exists in the skin layer. When light irradiates the photocatalyst fiber of the present invention, a photocatalytic reaction will occur to generate active oxygen and OH free radicals, and then bacteria will be killed, and odor substances will be decomposed and purified through strong redox reactions. At the same time, it also has anti-pollution and stain-proof properties. Therefore, the photocatalyst fiber of the present invention can be used not only for various products such as bedding, clothes, curtains, hats, etc., but also widely for industrial purposes.

[0010] The synthetic resin is pulverized by the air flow pulverization method and then mixed with the photocatalyst for granulation. The obtained masterbatch containing the photocatalyst can be made into a photocatalyst fiber with a skin-core structure by skin-core composite spinning. Since the air flow pulverization method can make the particle size of the pulverized synthetic resin smaller and the particle size distribution more uniform, compared with the commonly used granular materials or resin chips, it can be mixed with the photocatalyst more uniformly, and then the dispersion of the photocatalyst in the obtained masterbatch is better, and further in the skin layer of the photocatalyst fiber, the distribution of the photocatalyst is more uniform.

[0011] Since the photocatalyst only exists in the skin layer, it avoids the continuous damage to the overall internal structure of the fiber, and the photocatalyst therein is uniformly dispersed without agglomeration, further ensuring the mechanical properties of the photocatalyst fiber. The core layer of the photocatalyst contains a light stabilizer, which can resist the decomposition effect of light on the inside of the fiber. Compared with ordinary photocatalyst fibers, the photocatalyst fiber of the present invention will not cause obvious deterioration of the mechanical properties of the fiber due to photocatalytic decomposition, so it has better durability.

[0012] Meanwhile, in the present invention, the light stabilizer and the photocatalyst are separately added to different regions of the photocatalytic fiber, avoiding the influence of the presence of the light stabilizer on the photocatalytic effect of the photocatalyst. The photocatalyst is added to the fiber cortex, which is relatively closer to the external space of the photocatalytic fiber than the light stabilizer. Therefore, the photocatalyst contacts the light first before the light stabilizer in the core layer, and at the same time, the active oxygen and OH free radicals generated by its photocatalytic reaction can also diffuse to the external space faster, further avoiding the problem that the light stabilizer absorbs the light energy or captures the photocatalytic products, affecting the bactericidal and deodorizing functions of the photocatalytic fiber.

[0013] Furthermore, the volume ratio of the cortex to the core layer is 1:1 to 5, preferably 1:2 to 3.

[0014] Furthermore, in the cortex, the mass ratio of the synthetic resin is 80% to 99%, and the mass ratio of the photocatalyst is 1% to 20%;

[0015] Preferably, the mass ratio of the synthetic resin in the cortex is 85% to 95%, and the mass ratio of the photocatalyst is 5% to 15%.

[0016] Furthermore, in the core layer, the mass ratio of the light stabilizer is 0.1% to 10%, preferably 0.5% to 5%.

[0017] In the present invention, controlling the volume ratio of the cortex to the core layer, as well as the respective contents of the photocatalyst and the light stabilizer in the photocatalytic fiber within the above-mentioned ranges, can not only ensure that the photocatalyst fully exerts its photocatalytic effect, enabling the photocatalytic fiber to achieve effective antibacterial and deodorizing effects, but also avoid the weakening or inhibition of the effect of the light stabilizer on the photocatalyst, while improving the durability of the photocatalytic fiber and ensuring that the functionality of the photocatalytic fiber is not affected.

[0018] Furthermore, the synthetic resin includes a polymer material chemically synthesized from petroleum as a raw material;

[0019] Preferably, the synthetic resin includes at least one of polyester, nylon, and polypropylene;

[0020] Preferably, the core layer is a synthetic resin containing a light stabilizer; the type of synthetic resin used in the core layer may be the same as or different from that in the cortex.

[0021] In the present invention, the types of synthetic resins in the cortex and core layer of the photocatalytic fiber may be the same or different, and can be selected according to actual needs.

[0022] Furthermore, the photocatalyst includes a metal oxide-based photocatalyst, a metal sulfide-based photocatalyst, a visible light-responsive photocatalyst, or a composite photocatalyst.

[0023] In the present invention, when the photocatalyst is irradiated with ultraviolet or visible light, it becomes excited and exhibits strong oxidation ability. Specifically, the photocatalyst can generate reactive oxygen species and OH free radicals under light irradiation, and then decompose and purify odor substances through strong redox reactions. The above-mentioned metal oxide-based photocatalysts may include oxides such as TiO2, ZnO, RuO2, CoO, Ce2O3, Cr2O3, Rh2O3, V2O5, WO3, etc.; the metal sulfides may include sulfides such as ZnS and CdS; the visible light-responsive photocatalyst may be BiVO4, etc.

[0024] Furthermore, the light stabilizer includes at least one of ultraviolet absorbers, ultraviolet quenchers, and free radical scavengers;

[0025] Preferably, the ultraviolet absorber includes at least benzophenone-based ultraviolet absorbers or benzotriazole-based ultraviolet absorbers; the ultraviolet quencher includes metal complexes, preferably divalent nickel complexes; the free radical scavenger includes hindered amine-based free radical scavengers.

[0026] In the above solution, the ultraviolet absorber has the ability to absorb the ultraviolet part in sunlight and fluorescent light sources, and can slow down the aging of the synthetic resin in the photocatalyst fiber by absorbing part of the light energy. If the synthetic resin molecules have absorbed ultraviolet light and are excited to generate excited state energy, the ultraviolet quencher can eliminate the excited state energy on the excited molecules and make them return to the low energy state, avoiding the generation of free radicals in the synthetic resin molecular chain. Through the above process, the effect of slowing down the aging of the synthetic resin in the photocatalyst fiber under light irradiation can be achieved. The free radical scavenger can capture the active free radicals generated by the synthetic resin itself under light irradiation or by the photocatalyst under light irradiation, thereby blocking the further oxidative damage of these active groups to the organic polymer (i.e., the synthetic resin in the photocatalyst fiber), and thus preventing or delaying the photodegradation process.

[0027] The three light stabilizers, namely the ultraviolet absorber, the ultraviolet quencher, and the free radical scavenger, can be used alone in the photocatalyst fiber of the present invention. Preferably, the light stabilizer in the core layer of the photocatalyst fiber of the present invention includes at least two of the ultraviolet absorber, the ultraviolet quencher, and the free radical scavenger, and the combined use of different types of light stabilizers plays a synergistic effect to enhance the durability of the photocatalyst fiber under light irradiation.

[0028] Furthermore, the photocatalyst fiber also contains functional components;

[0029] Preferably, the functional components are added to the skin layer.

[0030] In the above solution, functional components can also be added to the photocatalyst fiber so that the photocatalyst fiber can provide additional functionality and can be used as a multifunctional composite fiber. The functional components can be added to the skin layer or the core layer of the photocatalyst fiber. Preferably, the functional components are added to the skin layer, which helps to achieve a stronger functional effect.

[0031] The functional components can be far-infrared components, negative ion components, phase change components, antibacterial components, antistatic components, fragrance components, etc., or specific functional components can be selected and added according to the specific functions to be achieved.

[0032] A method for preparing a photocatalyst fiber having a skin-core structure includes the following steps:

[0033] S1. Crush the synthetic resin by the air-flow crushing method to obtain synthetic resin powder;

[0034] S2. Mix the photocatalyst evenly with the synthetic resin powder obtained in step S1 to obtain a mixed powder;

[0035] S3. Make the mixed powder obtained in step S2 into a photocatalyst masterbatch;

[0036] S4. Use the photocatalyst masterbatch obtained in step S3 as the skin layer raw material and the synthetic resin containing a light stabilizer as the core layer raw material for skin-core composite spinning to obtain the photocatalyst fiber having a skin-core structure;

[0037] Among them, the type of synthetic resin used in step S1 is the same as or different from the type of synthetic resin used as the core layer raw material in step S4.

[0038] The photocatalyst fiber obtained by the preparation method of the present invention will not cause the photocatalyst to desorb due to washing. Therefore, its antibacterial, antifouling, deodorizing and other functions can be semi-permanent. By crushing the synthetic resin into a powder form by the air-flow crushing method, synthetic resin powder with a smaller particle size and a more uniform particle size distribution can be obtained, and then it can be more evenly mixed with the photocatalyst to obtain a photocatalyst masterbatch in which the photocatalyst has good dispersibility. Using the photocatalyst masterbatch and the synthetic resin containing a light stabilizer as the skin layer and the core layer raw materials respectively for skin-core composite spinning, the obtained photocatalyst fiber has the photocatalyst evenly dispersed in the skin layer, and the antibacterial and deodorizing effects can be achieved through the photocatalytic reaction. At the same time, the uniform dispersibility of the photocatalyst has little influence on the mechanical properties of the fiber. The light stabilizer contained in the core layer can not only prevent the inside of the photocatalyst fiber from aging rapidly under the action of light and photocatalyst, ensure that the mechanical properties of the photocatalyst fiber do not deteriorate significantly for a long time, but also will not affect the photocatalytic effect of the photocatalyst in the skin layer, improving the durability of the photocatalyst fiber.

[0039] Further, in step S1, the particle size of the obtained synthetic resin powder is controlled to be 1 to 500 μm, and preferably the particle size of the synthetic resin powder is controlled to be 2 to 50 μm;

[0040] In step S2, the photocatalyst is in powder form, and its particle size is 20 to 100 nm, preferably 40 to 60 nm.

[0041] In the present invention, it is found through testing that when the synthetic resin is pulverized into powder particles with a particle size of 20 to 500 μm, it can be adapted to the particle size of 20 to 100 nm of the photocatalyst, and thus the mixing uniformity of the synthetic resin and the photocatalyst in the obtained mixed powder is better. By improving the mixing uniformity of the synthetic resin and the photocatalyst in the mixed powder, the dispersion of the photocatalyst in the cortex of the obtained photocatalyst fiber is also better, and the photocatalyst fiber can further have better mechanical properties and photocatalytic properties.

[0042] Further, in step S1, the air jet milling method adopts a normal temperature air jet milling process or a low temperature cryogenic air jet milling process, and preferably adopts a low temperature cryogenic air jet milling process;

[0043] More preferably, the air flow rate for pulverizing the synthetic resin is 500 to 700 m / s, and the low temperature pulverization temperature is -20 to -150 °C, preferably -60 to -120 °C.

[0044] Specifically, in the present invention, an air jet mill is used to pulverize the synthetic resin chips. The air jet mill is preferably a fluidized bed air jet mill, and a low temperature cryogenic air jet milling process is adopted. Compared with the normal temperature air jet milling process, synthetic resin powder with a smaller particle size can be obtained, which helps to improve its mixing effect with the photocatalyst.

[0045] Further, in step S2, a high-speed mixer is used to mix the synthetic resin powder and the photocatalyst, which specifically includes the following steps:

[0046] S21. Heat the high-speed mixer to 60 to 70 °C;

[0047] S22. Add the synthetic resin powder obtained in step S1 to the high-speed mixer, and the high-speed mixer operates to disperse the synthetic resin powder for 4 to 8 minutes;

[0048] S23. Add the photocatalyst to the high-speed mixer and mix it with the synthetic resin powder to obtain a mixed powder.

[0049] Specifically, in step S22, after adding the synthetic resin powder, the high-speed mixer first disperses at 300 to 500 r / min for 3 to 5 minutes, and then rises to 800 to 1000 r / min and continues to disperse for 1 to 3 minutes.

[0050] In step S23, after the photocatalyst is added, the high-speed mixer is first started at a low speed. When the rotation speed is stabilized at 300 - 500 r / min, it is increased to 800 - 1000 r / min and continuously operated for 5 - 10 min.

[0051] Alternatively, the mixing of the synthetic resin powder and the photocatalyst in step S2 of the preparation method of the present invention can also be carried out synchronously with the crushing of the synthetic resin in step S1. Specifically, an air jet mill can be used to complete the crushing of the synthetic resin and the mixing of the crushed synthetic resin powder and the photocatalyst at one time, which can not only obtain a better dispersion effect but also save process costs.

[0052] Further, the core layer raw material used in step S4 is prepared according to the following steps:

[0053] A. Crush the synthetic resin by the air jet milling method to obtain the core layer synthetic resin powder;

[0054] B. Mix the core layer synthetic resin powder obtained in step A with a light stabilizer evenly to obtain a mixture, which is the core layer raw material;

[0055] Among them, the mixture is a powder.

[0056] In the above solution, when the skin layer and the core layer of the photocatalyst fiber adopt the same synthetic resin, the synthetic resin powder obtained in step S1 can be divided into two parts. One part is used for mixing with the photocatalyst in step S2 to make a photocatalyst masterbatch, and the other part is used as the core layer synthetic resin powder and mixed with the light stabilizer in step B above. At this time, step B can be directly carried out without carrying out step A.

[0057] In the present invention, the synthetic resin used in the core layer raw material is also crushed by an air jet milling process and then mixed with a light stabilizer. In the core layer of the obtained photocatalyst fiber, the distribution of the light stabilizer is more uniform. On the one hand, it is beneficial to the uniformity and continuity of the core layer of the photocatalyst fiber and ensures the initial mechanical strength of the fiber. On the other hand, it can uniformly improve the anti-aging and anti-photolysis capabilities of the photocatalyst fiber everywhere, avoiding faster local aging of the fiber and affecting its durability.

[0058] Further, in step A, the conditions for crushing the synthetic resin are the same as those in step S1, that is:

[0059] Control the particle size of the obtained core layer synthetic resin powder to be 20 - 500 μm, preferably 50 - 100 μm;

[0060] The air jet milling method preferably adopts a low-temperature cryogenic air jet milling process; the air flow rate for crushing the synthetic resin is 500 - 700 m / s, and the low-temperature crushing temperature is -20 - -150 °C, preferably -60 - -120 °C.

[0061] Further, in step B, the method for mixing the core layer synthetic resin powder and the light stabilizer is the same as the method for mixing the photocatalyst and the synthetic resin powder in step S2, that is, it is carried out according to the following steps:

[0062] B1. Heat the high-speed mixer to 60-70 °C;

[0063] B2. Add the core layer synthetic resin powder to the high-speed mixer. The high-speed mixer is first dispersed at 300-500 r / min for 3-5 min, and then raised to 800-1000 r / min and continuously dispersed for 1-3 min;

[0064] B3. Add the light stabilizer to the high-speed mixer. The high-speed mixer starts at a low speed. When the rotation speed is stable at 300-500 r / min, it is raised to 800-1000 r / min and continuously runs for 5-10 min to be mixed with the core layer synthetic resin powder to obtain a mixture.

[0065] Further, in step S2, in the obtained mixed powder, the mass ratio of the synthetic resin powder is 80%-99%, and the mass ratio of the photocatalyst is 1%-20%;

[0066] Preferably, the mass ratio of the synthetic resin is 85%-95%, and the mass ratio of the photocatalyst is 5%-15%.

[0067] Further, in step S3, the mixed powder obtained in step S2 is fed into an extruder and melt-extruded through the extruder to prepare a photocatalyst masterbatch.

[0068] Further, in step S4, the volume ratio of the photocatalyst masterbatch to the synthetic resin used in the core layer raw material is 1:1-5, preferably 1:2-3.

[0069] Further, in step S4, in the core layer raw material, the addition amount of the light stabilizer is 0.1%-10% of the total mass of the core layer raw material, preferably 0.5%-5%.

[0070] After adopting the above technical solution, the present invention has the following beneficial effects compared with the prior art.

[0071] 1. The photocatalyst fiber of the present invention has a skin-core structure. The photocatalyst is added to its skin layer, while the core layer does not contain the photocatalyst, which is used to enhance the overall strength of the photocatalyst fiber and ensure good mechanical properties. At the same time, the core layer of the photocatalyst fiber is added with a light stabilizer, which effectively prevents the self-photolysis of the core layer part of the photocatalyst fiber, thereby avoiding the aging of the interior of the photocatalyst fiber after long-term light irradiation, ensuring that the mechanical properties of the photocatalyst fiber can be maintained stable for a longer time, and enhancing the durability of the photocatalyst fiber.

[0072] 2. When preparing the photocatalyst masterbatch as the raw material for the cortex, the synthetic resin is pulverized by the air-flow pulverization method and then mixed with the photocatalyst to obtain a mixed powder. On the one hand, the photocatalyst will not fall off due to the use or washing of the photocatalyst fibers, ensuring longer functionality. On the other hand, the synthetic resin powder obtained by air-flow pulverization has a smaller particle size and a more uniform particle size distribution, and can achieve a more uniform mixing effect with the photocatalyst of micro-nano size. Furthermore, it can improve the dispersibility of the photocatalyst in the photocatalyst masterbatch and the cortex of the photocatalyst fibers, avoiding the phenomenon of local particle agglomeration. In this way, the mechanical properties and processability of the photocatalyst fibers can be improved.

[0073] The following further describes in detail the specific embodiments of the present invention with reference to the accompanying drawings. Description of the Drawings

[0074] The accompanying drawings, as a part of the present invention, are used to provide a further understanding of the present invention. The schematic embodiments and descriptions thereof of the present invention are used to explain the present invention, but do not constitute an improper limitation to the present invention. Obviously, the accompanying drawings in the following description are only some embodiments, and those of ordinary skill in the art can obtain other drawings based on these drawings without creative efforts. In the drawings:

[0075] Figure 1 is a schematic structural diagram of the photocatalyst fiber in the present invention;

[0076] Figure 2 is a process flow chart of the preparation method of the photocatalyst fiber of the present invention.

[0077] In the figure: 1. Cortex; 2. Core layer.

[0078] It should be noted that these drawings and text descriptions are not intended to limit the scope of the concept of the present invention in any way, but to illustrate the concept of the present invention to those skilled in the art by referring to specific embodiments. Specific Embodiments

[0079] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments will be clearly and completely described below. The following embodiments are used to illustrate the present invention, but are not used to limit the scope of the present invention.

[0080] As Figure 1 shown, the present invention provides a photocatalyst fiber, including a cortex 1 and a core layer 2. Among them, the cortex 1 includes a synthetic resin and a photocatalyst, and the photocatalyst is uniformly dispersed in the synthetic resin forming the cortex. The core layer 2 includes a synthetic resin and a light stabilizer.

[0081] In the present invention, the synthetic resin used in the skin layer 1 of the photocatalyst fiber and the synthetic resin used in the core layer 2 may be of the same type or different types.

[0082] As Figure 2 shown, the present invention also provides a method for preparing a photocatalyst fiber, comprising the following steps:

[0083] S1. Crushing the synthetic resin by airflow pulverization method to obtain synthetic resin powder;

[0084] S2. Mixing the photocatalyst evenly with the synthetic resin powder obtained in step S1 to obtain a mixed powder;

[0085] S3. Making the mixed powder obtained in step S2 into a photocatalyst masterbatch;

[0086] S4. Using the photocatalyst masterbatch obtained in step S3 as the skin layer raw material and the synthetic resin containing a light stabilizer as the core layer raw material to perform skin-core composite spinning to obtain a photocatalyst fiber with a skin-core structure.

[0087] The following describes the specific embodiments of the present invention.

[0088] Example 1

[0089] In the photocatalyst fiber prepared in this example, PA6 is selected as the synthetic resin, and TiO2 powder with an average particle size of 50 nm is selected as the photocatalyst, and it is prepared through the following steps:

[0090] S1. Using a low-temperature cryogenic airflow pulverizer, setting the airflow speed at 500 m / s and the pulverization temperature at -60 °C, pulverizing the PA6 chips to a particle size of 10 - 20 μm to obtain PA6 fine powder;

[0091] S2. Adding a part of the PA6 fine powder obtained in step S1 to a high-speed mixer preheated to 60 - 70 °C, dispersing at a rotation speed of 480 r / min for 3 min, raising the rotation speed to 960 r / min, and continuing to disperse for 1 min; when the high-speed mixer is in a stopped state, adding TiO2 powder, starting at a low speed, mixing at a rotation speed of 480 r / min for 1 min, then raising the rotation speed to 960 r / min, and continuing to mix for 5 min to obtain a mixed powder; in the mixed powder, the mass ratio of the PA6 fine powder is 95%, and the mass ratio of the TiO2 powder is 5%;

[0092] S3. Feeding the mixed powder obtained in step S2 into a twin-screw extruder to prepare a photocatalyst masterbatch M1; among them, the temperatures of each zone of the twin-screw extruder are 255 °C, 250 °C, 250 °C, 250 °C, 250 °C, 250 °C, 250 °C, 250 °C, 250 °C, 250 °C, 180 °C, the main machine rotation speed is 180 r / min, and the feeding rotation speed is 25 r / min;

[0093] B. Add another part of the PA6 fine powder obtained in step S1 to a high-speed mixer preheated to 60 - 70°C, disperse it at a rotation speed of 480 r / min for 3 min, increase the rotation speed to 960 r / min, and continue to disperse for 1 min; with the high-speed mixer in a stopped state, add high molecular weight hindered amine light stabilizer CHIMASSORB 2020 (accounting for 0.6 wt% of the mixture obtained after mixing) and benzophenone ultraviolet absorber CHIMASSORB 81 (accounting for 0.4 wt% of the mixture obtained after mixing), start at a low speed, mix at a rotation speed of 480 r / min for 1 min, then increase the rotation speed to 960 r / min, and continue to mix for 5 min to obtain a mixture.

[0094] S4. Using photocatalyst masterbatch M1 as the skin layer raw material and the mixture obtained in step B as the core layer raw material, with a skin-core volume ratio of 1:1, use a skin-core composite spinning device to perform skin-core composite spinning, control the fiber denier to be 110D, and the draw ratio to be 1.25 times to obtain photocatalyst fibers with a skin-core structure.

[0095] Example 2

[0096] In the photocatalyst fibers prepared in this example, the synthetic resin is PET, and the photocatalyst is TiO2 powder with an average particle size of 50 nm. The preparation is carried out through the following steps:

[0097] S1. Using a low-temperature cryogenic air-flow pulverizer, set the air-flow speed at 600 m / s and the pulverizing temperature at -80°C, pulverize PET chips to a particle size of 7 - 15 μm to obtain PET fine powder.

[0098] S2. Add part of the PET fine powder obtained in step S1 to a high-speed mixer preheated to 60 - 70°C, disperse it at a rotation speed of 480 r / min for 3 min, increase the rotation speed to 960 r / min, and continue to disperse for 1 min; with the high-speed mixer in a stopped state, add TiO2 powder, start at a low speed, mix at a rotation speed of 480 r / min for 1 min, then increase the rotation speed to 960 r / min, and continue to mix for 5 min to obtain a mixed powder; in the mixed powder, the mass ratio of PET fine powder is 90%, and the mass ratio of TiO2 powder is 10%.

[0099] S3. Feed the mixed powder obtained in step S2 into a twin-screw extruder to prepare photocatalyst masterbatch M2; among them, the temperatures of each zone of the twin-screw extruder are 100°C, 180°C, 215°C, 210°C, 210°C, 208°C, 203°C, 195°C, 170°C, 160°C, 205°C respectively, the main machine rotation speed is 300 r / min, and the feeding rotation speed is 180 r / min.

[0100] B. Another part of the PET fine powder obtained in step S1 is added to a high-speed mixer preheated to 60 - 70°C, dispersed at a rotation speed of 480 r / min for 3 min, the rotation speed is increased to 960 r / min, and dispersion continues for 1 min. In the state where the high-speed mixer is stopped, a high molecular weight hindered amine light stabilizer CHIMASSORB 2020 (accounting for 0.5 wt% of the mixture obtained after mixing) and an ultraviolet absorber TINUVIN 328 (accounting for 0.5 wt% of the mixture obtained after mixing) are added, started at a low speed, mixed at a rotation speed of 480 r / min for 1 min, then the rotation speed is increased to 960 r / min, and mixing continues for 5 min to obtain a mixture.

[0101] S4. Using the photocatalyst masterbatch M2 as the skin layer raw material and the mixture obtained in step B as the core layer raw material, with a skin-core volume ratio of 1:3, a skin-core composite spinning device is used for skin-core composite spinning, controlling the fiber denier to be 175 D and the draw ratio to be 2.7 times to obtain photocatalyst fibers with a skin-core structure.

[0102] Example 3

[0103] In the photocatalyst fibers prepared in this example, the synthetic resin selects PET, the photocatalyst selects BiVO4 powder with an average particle size of 80 nm, and is combined with negative ion powder with an average particle size of 60 nm, and is prepared through the following steps:

[0104] S1. Using a low-temperature cryogenic air flow pulverizer, setting the air flow speed at 600 m / s and the pulverizing temperature at -100°C, pulverize the PET chips to a particle size of 5 - 10 μm to obtain PET fine powder.

[0105] S2. Part of the PET fine powder obtained in step S1 is added to a high-speed mixer preheated to 60 - 70°C, dispersed at a rotation speed of 480 r / min for 3 min, the rotation speed is increased to 960 r / min, and dispersion is carried out for 1 min. In the state where the high-speed mixer is stopped, BiVO4 powder and negative ion powder are added, started at a low speed, mixed at a rotation speed of 480 r / min for 1 min, then the rotation speed is increased to 960 r / min, and mixing continues for 5 min to obtain a mixed powder. In the mixed powder, the mass ratio of PET fine powder is 90%, the mass ratio of BiVO4 powder is 8%, and the mass ratio of negative ion powder is 2%.

[0106] S3. Feed the mixed powder obtained in step S2 into a twin-screw extruder to prepare a photocatalyst masterbatch M3. Among them, the temperatures of each zone of the twin-screw extruder are 100°C, 180°C, 215°C, 210°C, 210°C, 208°C, 203°C, 195°C, 170°C, 160°C, 205°C respectively, the main machine rotation speed is 300 r / min, and the feeding rotation speed is 180 r / min.

[0107] B. Add another part of the PET fine powder obtained in step S1 to a high-speed mixer preheated to 60 - 70°C, disperse it at a rotational speed of 480 r / min for 3 min, increase the rotational speed to 960 r / min, and continue to disperse for 1 min. With the high-speed mixer in a stopped state, add hindered amine light stabilizer TINUVIN 944 (accounting for 0.6 wt% of the mixture obtained after mixing) and ultraviolet absorber TINUVIN 328 (accounting for 0.6 wt% of the mixture obtained after mixing), start at a low speed, mix at a rotational speed of 480 r / min for 1 min, then increase the rotational speed to 960 r / min, and continue to mix for 5 min to obtain a mixture.

[0108] S4. Use photocatalyst masterbatch M3 as the skin layer raw material and the mixture obtained in step B as the core layer raw material. According to a skin-core volume ratio of 1:2, use a skin-core composite spinning device for skin-core composite spinning, control the fiber denier to be 175 D, and the draw ratio to be 2.7 times to obtain photocatalyst fibers with a skin-core structure.

[0109] Example 4

[0110] The difference between this example and Example 1 above is that the resin raw material PA6 of the skin layer and the core layer is treated by cryogenic mechanical impact pulverization.

[0111] Specifically, this example is prepared according to the following steps:

[0112] S1. Use a low-temperature mechanical impact pulverizer, set the air flow velocity at 100 m / s and the pulverization temperature at -10°C, pulverize the PA6 chips to a particle size of 50 - 120 μm to obtain PA6 fine powder.

[0113] S2. Add a part of the PA6 fine powder obtained in step S1 to a high-speed mixer preheated to 60 - 70°C, disperse it at a rotational speed of 480 r / min for 3 min, increase the rotational speed to 960 r / min, and continue to disperse for 1 min. With the high-speed mixer in a stopped state, add TiO2 powder with a particle size of 50 nm, start at a low speed, mix at a rotational speed of 480 r / min for 1 min, increase the rotational speed to 960 r / min, and continue to mix for 5 min to obtain a mixed powder. In the mixed powder, the mass ratio of PA6 fine powder is 95%, and the mass ratio of TiO2 powder is 5%.

[0114] S3. Feed the mixed powder obtained in step S2 into a twin-screw extruder to prepare photocatalyst masterbatch M6. Among them, the temperatures of each zone of the twin-screw extruder are 255°C, 250°C, 250°C, 250°C, 250°C, 250°C, 250°C, 250°C, 250°C, 250°C, 180°C, the main machine rotational speed is 180 r / min, and the feeding rotational speed is 25 r / min.

[0115] B. Another part of the PA6 fine powder obtained in step S1 is added to a high-speed mixer preheated to 60 - 70°C, dispersed at a rotational speed of 480 r / min for 3 min, the rotational speed is increased to 960 r / min, and dispersion continues for 1 min; in the state where the high-speed mixer is stopped, a high molecular weight hindered amine light stabilizer CHIMASSORB 2020 (accounting for 0.6 wt% of the mixture obtained after mixing) and a benzophenone ultraviolet absorber CHIMASSORB 81 (accounting for 0.4 wt% of the mixture obtained after mixing) are added, started at a low speed, mixed at a rotational speed of 480 r / min for 1 min, then the rotational speed is increased to 960 r / min, and mixing continues for 5 min to obtain a mixture.

[0116] S4. Using the photocatalyst masterbatch M6 as the skin layer raw material and the mixture obtained in step B as the core layer raw material, with a skin-core volume ratio of 1:1, a skin-core composite spinning device is used for skin-core composite spinning, controlling the fiber denier to be 110 D and the draw ratio to be 1.25 times to obtain a photocatalyst fiber with a skin-core structure.

[0117] Comparative Example 1

[0118] The difference between this comparative example and Example 1 above is that: the skin layer raw material is PA6 fine powder without photocatalyst.

[0119] Specifically, in this comparative example, PA6 fine powder is prepared as the skin layer raw material according to step S1 of Example 1, the mixture is prepared as the core layer raw material according to step B of Example 1, and the same preparation process as in step S4 of Example 1 is used for skin-core composite spinning, that is, the skin-core volume ratio is 1:1, the fiber denier is 110 D, and the draw ratio is 1.25 times to obtain a nylon composite fiber with a skin-core structure.

[0120] Comparative Example 2

[0121] The difference between this comparative example and Example 1 above is that: the core layer raw material is PA6 without adding light stabilizer.

[0122] Specifically, in this comparative example, the photocatalyst masterbatch M1 is prepared according to steps S1 to S3 of Example 1, then the photocatalyst masterbatch M1 is used as the skin layer raw material, PA6 fine powder is prepared as the core layer raw material according to step S1 of Example 1, and the same preparation process as in step S4 of Example 1 is used for skin-core composite spinning, that is, the skin-core volume ratio is 1:1, the fiber denier is 110 D, and the draw ratio is 1.25 times to obtain a photocatalyst fiber with a skin-core structure.

[0123] Comparative Example 3

[0124] The difference between this comparative example and the above-mentioned Example 1 is that both the skin layer raw material and the core layer raw material are PA6, that is, the skin layer raw material does not contain photocatalyst, and the core layer raw material does not add light stabilizer.

[0125] Specifically, in this comparative example, PA6 fine powder was prepared according to the steps S1 in Example 1, and used as the skin layer raw material and the core layer raw material respectively, and the same preparation process as in step S4 of Example 1 was used for skin-core composite spinning, that is, the skin-core volume ratio was 1:1, the fiber denier was 110D, and the draw ratio was 1.25 times, to obtain a nylon composite fiber with a skin-core structure.

[0126] Comparative Example 4

[0127] The difference between this comparative example and the above-mentioned Example 1 is that the skin layer raw material and the core layer raw material are swapped for skin-core composite spinning.

[0128] Specifically, in this comparative example, the photocatalyst masterbatch M1 was prepared according to the steps S1 to S3 in Example 1, and then the photocatalyst masterbatch M1 was used as the core layer raw material, and a mixture obtained by uniformly mixing PA6 fine powder with 0.6 wt% of high molecular weight hindered amine light stabilizer CHIMASSORB 2020 and 0.4 wt% of benzophenone ultraviolet absorber CHIMASSORB 81 according to step B in Example 1 was used as the skin layer raw material, and the same preparation process as in step S4 of Example 1 was used for skin-core composite spinning, that is, the skin-core volume ratio was 1:1, the fiber denier was 110D, and the draw ratio was 1.25 times, to obtain a photocatalyst fiber with a skin-core structure.

[0129] Comparative Example 5

[0130] The difference between this comparative example and the above-mentioned Example 1 is that both the skin layer raw material and the core layer raw material are the photocatalyst masterbatch M1.

[0131] Specifically, in this comparative example, the photocatalyst masterbatch M1 was prepared according to the steps S1 to S3 in Example 1, and then the photocatalyst masterbatch M1 was used as both the skin layer raw material and the core layer raw material, and the same preparation process as in step S4 of Example 1 was used for skin-core composite spinning, that is, the skin-core volume ratio was 1:1, the fiber denier was 110D, and the draw ratio was 1.25 times, to obtain a photocatalyst fiber with a skin-core structure.

[0132] Comparative Example 6

[0133] The difference between this comparative example and the above-mentioned Example 1 is that the skin layer raw material is PA6 added with photocatalyst and light stabilizer, and the core layer raw material is PA6 fine powder.

[0134] Specifically, this comparative example was prepared according to the following steps:

[0135] S1. Use a low-temperature cryogenic air-flow pulverizer, set the air-flow speed at 500 m / s and the pulverizing temperature at -60°C, pulverize the PA6 chips to a particle size of 10 - 20 μm to obtain PA6 fine powder;

[0136] S2. Add part of the PA6 fine powder obtained in step S1 to a high-speed mixer preheated to 60 - 70°C, disperse it at a rotational speed of 480 r / min for 3 min, increase the rotational speed to 960 r / min, and continue to disperse for 1 min; with the high-speed mixer in a stopped state, add TiO2 powder with a particle size of 50 nm, high-molecular-weight hindered amine light stabilizer CHIMASSORB 2020 (accounting for 0.6 wt% of the obtained mixed powder) and benzophenone ultraviolet absorber CHIMASSORB 81 (accounting for 0.4 wt% of the obtained mixed powder), start at a low speed, mix at a rotational speed of 480 r / min for 1 min, then increase the rotational speed to 960 r / min, and continue to mix for 5 min to obtain a mixed powder; in the said mixed powder, the mass ratio of the PA6 fine powder is 94%, the mass ratio of the TiO2 powder is 5%, and the total mass ratio of the light stabilizers is 1%;

[0137] S3. Feed the mixed powder obtained in step S2 into a twin-screw extruder to prepare the photocatalyst masterbatch M4; among them, the temperatures of each zone of the twin-screw extruder are 255°C, 250°C, 250°C, 250°C, 250°C, 250°C, 250°C, 250°C, 250°C, 250°C, 180°C respectively, the main machine rotational speed is 180 r / min, and the feeding rotational speed is 25 r / min;

[0138] S4. Use the photocatalyst masterbatch M4 as the skin layer raw material and the PA6 fine powder obtained in step S1 as the core layer raw material, according to a skin-core volume ratio of 1:1, use a skin-core composite spinning device for skin-core composite spinning, control the fiber denier to be 110 D, and the draw ratio to be 1.25 times to obtain a photocatalyst fiber with a skin-core structure.

[0139] Comparative Example 7

[0140] The difference between this comparative example and the above Example 1 is that: the raw materials of both the skin layer and the core layer are PA6 added with photocatalyst and light stabilizer.

[0141] Specifically, in this comparative example, the photocatalyst masterbatch M4 is prepared according to steps S1 to S3 in Comparative Example 6, and then the said photocatalyst masterbatch M4 is used as both the skin layer raw material and the core layer raw material, and the same preparation process as in step S4 of Example 1 is adopted for skin-core composite spinning, that is, the skin-core volume ratio is 1:1, the fiber denier is 110 D, and the draw ratio is 1.25 times to obtain a photocatalyst fiber with a skin-core structure.

[0142] Comparative Example 8

[0143] The difference between this comparative example and the above-mentioned Example 1 is that the resin raw material PA6 of the cortex and the core layer is not subjected to air-flow pulverization, and PA6 chips are directly used for spinning.

[0144] Specifically, this comparative example is prepared according to the following steps:

[0145] S1. Add PA6 chips to a high-speed mixer preheated to 60-70°C, disperse at a rotation speed of 480 r / min for 3 min, increase the rotation speed to 960 r / min, and continue to disperse for 1 min; when the high-speed mixer is in a stopped state, add TiO2 powder with a particle size of 50 nm, start at a low speed, mix at a rotation speed of 480 r / min for 1 min, then increase the rotation speed to 960 r / min, and continue to mix for 5 min to obtain a mixed powder; in the mixed material, the mass ratio of PA6 chips is 95%, and the mass ratio of TiO2 powder is 5%.

[0146] S2. Feed the mixed powder obtained in step S2 into a twin-screw extruder to prepare a photocatalyst masterbatch M5; among them, the temperatures of each zone of the twin-screw extruder are 255°C, 250°C, 250°C, 250°C, 250°C, 250°C, 250°C, 250°C, 250°C, 250°C, 180°C, the main machine rotation speed is 180 r / min, and the feeding rotation speed is 25 r / min;

[0147] B. Add PA6 chips to a high-speed mixer preheated to 60-70°C, disperse at a rotation speed of 480 r / min for 3 min, increase the rotation speed to 960 r / min, and continue to disperse for 1 min; when the high-speed mixer is in a stopped state, add high molecular weight hindered amine light stabilizer CHIMASSORB 2020 (accounting for 0.6 wt% of the mixed material obtained after mixing) and benzophenone ultraviolet absorber CHIMASSORB 81 (accounting for 0.4 wt% of the mixed material obtained after mixing), start at a low speed, mix at a rotation speed of 480 r / min for 1 min, then increase the rotation speed to 960 r / min, and continue to mix for 5 min to obtain a mixed material;

[0148] S3. Use the photocatalyst masterbatch M5 as the cortex raw material and the mixed material obtained in step B as the core layer raw material, carry out core-sheath composite spinning using a core-sheath composite spinning device according to a core-sheath volume ratio of 1:1, control the fiber denier to be 110 D, and the draw ratio to be 1.25 times to obtain a photocatalyst fiber with a core-sheath structure.

[0149] Test Example 1

[0150] To compare the functionality of the fibers obtained in the above examples and comparative examples, the antibacterial and deodorizing functions of the fibers were tested, and the specific test methods are as follows.

[0151] Test conditions: To compare the photocatalytic effect, under the same conditions, ultraviolet light with an intensity of 1 mW / cm 2 was used to irradiate the tested samples, and the test process was observed.

[0152] (1) Determination of antibacterial effect by proliferation method:

[0153] Tested samples: The fiber filaments were woven into a plain woven fabric (weft density: 260 threads / 10 cm), with a size of 10 cm × 10 cm;

[0154] Test strain: Escherichia coli;

[0155] Cultivation method: The number of bacteria was measured after culturing at 25 °C for 24 hours.

[0156] (2) Deodorization effect test using ammonia gas:

[0157] In a sealed transparent container (10 cm × 10 cm × 10 cm), the above-mentioned woven fabric of 10 cm × 10 cm was placed at the bottom and 300 ppm of ammonia gas was added. After irradiating with ultraviolet light for 300 min, the gas was extracted by an airtight gas syringe, and the reduction of ammonia gas content was determined by gas chromatography analysis.

[0158] The test results of this test example are shown in Table 1 below.

[0159] Table 1

[0160] Test item Bacterial reduction rate % Ammonia reduction rate % Example 1 96 85 Example 2 95 87 Example 3 97 88 Example 4 88 80 Comparative example 1 5 3 Comparative example 2 94 84 Comparative example 3 6 3 Comparative example 4 8 4 Comparative example 5 97 89 Comparative example 6 12 9 Comparative example 7 10 6 Comparative example 8 82 74

[0161] Test Example 2

[0162] This test example tested the light aging resistance of the fibers obtained in the above-mentioned examples and comparative examples under light conditions.

[0163] Specifically, the initial tensile strength and elongation at break of the tested sample fibers were tested. Then, the sample fibers were placed in a room temperature environment and irradiated with ultraviolet light with a wavelength of 365 nm and an intensity of 360 μW / cm 2 . After placing for one week, the tensile strength test was carried out again. The test results are shown in Table 2 below.

[0164] Table 2

[0165] Test item Initial tensile strength (g / d) Initial elongation at break (%) Tensile strength after aging (g / d) Strength reduction rate (%) Example 1 3.52 28.2 3.16 10.2 Example 2 2.89 18.2 2.63 9.0 Example 3 3.26 20.2 2.95 9.6 Example 4 3.24 25.9 2.90 10.5 Comparative example 1 4.08 30.1 3.85 5.6 Comparative example 2 3.56 29.4 1.9 46.7 Comparative example 3 4.20 34.1 2.63 37.4 Comparative example 4 3.38 21.5 3.15 6.9 Comparative example 5 3.18 16.7 1.18 62.9 Comparative example 6 3.62 29.0 2.73 24.6 Comparative example 7 3.15 15.6 2.56 18.7 Comparative example 8 3.06 23.5 2.67 12.7

[0166] From the test results of Test Examples 1 and 2 above, it can be seen that the photocatalytic fibers obtained in Examples 1-4 have good antibacterial and deodorizing effects, indicating that the photocatalyst in the skin layer can effectively play a photocatalytic role under light conditions, killing bacteria and decomposing harmful gases. At the same time, after one week of ultraviolet irradiation, the tensile strength of the photocatalytic fiber only decreases by 9.0% - 10.5%, indicating that while the photocatalyst is functioning, the internal structure of the fiber does not undergo obvious degradation. It can be seen that the light stabilizer in the core layer ensures the tensile strength of the photocatalytic fiber after irradiation, thereby extending the service time of the photocatalytic fiber and having the effect of improving the durability of the fiber.

[0167] Compared with the nylon composite fiber without photocatalyst in Comparative Example 3, the strength reduction rate of the photocatalytic fiber obtained in Comparative Example 2 after one week of ultraviolet irradiation is nearly 10% higher, indicating that without adding a light stabilizer, the addition of the photocatalyst will accelerate the aging of the fiber. By comparing the test results of the photocatalytic fiber obtained in Example 1 with the fibers prepared in Comparative Examples 2 and 3, it can be seen that the initial strength of the photocatalytic fiber in Example 1 does not decrease significantly compared with Comparative Examples 2 and 3, indicating that the addition of the photocatalyst and the light stabilizer does not significantly damage the continuity of the internal structure of the fiber; after one week of ultraviolet irradiation, the strength reduction rate of the photocatalytic fiber in Example 1 is only 8.9%, significantly lower than that of the fibers without light stabilizer in Comparative Examples 2 and 3, indicating that the addition of the light stabilizer effectively inhibits the decomposition effect of light on the inside of the fiber, significantly improving the durability of the photocatalytic fiber.

[0168] When comparing the test results of the fibers obtained in Example 1 and Comparative Example 1 respectively, in the case of adding a photocatalyst, the initial tensile strength and elongation of the fiber only decrease slightly, but the measured bacteria reduction rate and ammonia reduction rate both show a significant increase, indicating that the solution of the present invention can ensure the full play of the photocatalyst while ensuring the mechanical properties of the fiber.

[0169] By comparing the test results of the fibers obtained in Example 1 and Comparative Example 4 respectively, it can be found that although the light stabilizer added in Comparative Example 4 also achieves the effect of inhibiting fiber aging, the measured bacteria reduction rate and ammonia reduction rate are very low. This shows that adding the photocatalyst to the skin layer close to the outer surface of the fiber in Example 1 can play a more effective photocatalytic role, while inside the fiber, the photocatalyst cannot effectively play a role.

[0170] By comparing the test results of the fibers obtained from Example 1 and Comparative Example 5 respectively, when the same proportion of photocatalyst is added to both the fiber cortex and the core layer, compared with adding the same proportion of photocatalyst only to the cortex, the bactericidal and deodorizing effects are not significantly improved, but the mechanical properties are reduced. At the same time, when comparing Comparative Example 2 and Comparative Example 5, when the photocatalyst is also added to the core layer, after ultraviolet irradiation, the fiber strength reduction rate is higher, indicating that the durability of the fiber is worse. And the present invention effectively solves the problem of poor fiber durability by adding a light stabilizer to the core layer. Therefore, considering from the perspectives of performance, raw material utilization rate and cost, adding the photocatalyst only to the cortex has a higher cost performance.

[0171] By comparing the test results of the fibers obtained from Example 1 and Comparative Examples 6 and 7 respectively, when the photocatalyst and the light stabilizer are added to the cortex / core layer at the same time, the antibacterial ability and deodorizing ability of the fiber both decrease significantly, indicating that adding the light stabilizer and the photocatalyst at the same position will affect the photocatalytic effect of the photocatalyst, making it difficult to achieve good antibacterial and deodorizing effects. Even though the proportion of the photocatalyst in the fiber is larger in Comparative Example 7, since the increased photocatalyst is in the fiber core layer and is also affected by the light stabilizer, the improvement of its photocatalytic performance is not obvious, and instead it will cause a decrease in the initial tensile strength and elongation at break of the fiber.

[0172] By comparing the test results of the fibers obtained from Example 1, Example 4 and Comparative Example 8 respectively, as the particle size of the resin powder is reduced, the mechanical strength of the prepared fiber is greatly improved. The fiber made from the PA6 fine powder obtained by cryogenic deep cold air pulverization (Example 1) has a 15% increase in mechanical strength and a 20% increase in elongation at break compared with the fiber made from PA6 chips (Comparative Example 8). This is because the mixing of the synthetic resin powder and the powder photocatalyst is more uniform, and the uniformity and continuity of the fiber are better. Correspondingly, due to the more uniform distribution of the photocatalyst inside the fiber, less agglomeration and a larger specific surface area, its photocatalytic effect is more sufficient, and the antibacterial and deodorizing properties are also more excellent.

[0173] Example 4 uses a normal temperature air pulverization process to pulverize PA6, and compared with Comparative Example 8, PA6 fine powder with a smaller particle size can be obtained, and thus the prepared fiber is superior to Comparative Example 8 in antibacterial and deodorizing properties and initial mechanical properties. However, compared with Example 1, the PA6 fine powder obtained in Example 4 has a larger particle size, and the prepared fiber has a decrease in photocatalytic performance and durability.

[0174] The above are only the preferred embodiments of the present invention, and there is no limitation to the present invention in any form. Although the present invention has been disclosed above with the preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art of this patent, without departing from the scope of the technical solution of the present invention, can make some changes or modifications using the technical content prompted above to form equivalent embodiments of equivalent changes. However, as long as it does not depart from the content of the technical solution of the present invention, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention still fall within the scope of the present invention's solution.

Claims

1. A photocatalytic fiber with a skin-core structure, comprising a skin layer and a core layer, characterized in that, The cortex includes synthetic resin and photocatalyst. Among them, the synthetic resin is pulverized by air flow and then mixed and granulated with the photocatalyst for spinning; the core layer contains a light stabilizer; In the cortex, the synthetic resin is pulverized to a particle size of 10-20 μm by a low-temperature cryogenic air flow pulverization process and mixed and granulated with a photocatalyst having a particle size of 40-60 nm; The light stabilizer includes a free radical scavenger, and the free radical scavenger can capture the active free radicals generated by the photocatalyst under light illumination conditions.

2. The photocatalytic fiber having a core-shell structure according to claim 1, wherein, The volume ratio of the cortex to the core layer is 1:1-5.

3. The photocatalytic fiber with a core-shell structure according to claim 2, characterized in that, The volume ratio of the cortex to the core layer is 1:2-3.

4. The photocatalytic fiber having a core-shell structure according to claim 1, wherein, In the cortex, the mass ratio of the synthetic resin is 80%-99%, and the mass ratio of the photocatalyst is 1%-20%.

5. The photocatalytic fiber with a skin-core structure according to claim 4, characterized in that, In the cortex, the mass ratio of the synthetic resin is 85%-95%, and the mass ratio of the photocatalyst is 5%-15%.

6. The photocatalytic fiber having a core-shell structure according to claim 1, wherein In the core layer, the mass ratio of the light stabilizer is 0.1%-10%.

7. The photocatalytic fiber with a skin-core structure according to claim 6, wherein In the core layer, the mass ratio of the light stabilizer is 0.5%-5%.

8. The photocatalytic fiber with a skin-core structure according to any one of claims 1-7, characterized in that, The synthetic resin includes a polymer material chemically synthesized from petroleum as a raw material.

9. The photocatalytic fiber having a core-shell structure according to claim 8, characterized in that, The synthetic resin includes at least one of polyester, nylon, and polypropylene.

10. The photocatalytic fiber having a skin-core structure according to claim 8, wherein, The core layer is a synthetic resin containing a light stabilizer; the type of synthetic resin used in the core layer is the same as or different from the type of synthetic resin in the cortex.

11. The photocatalytic fiber with a skin-core structure according to any one of claims 1-7, characterized in that, The light stabilizer includes at least one of an ultraviolet absorber and an ultraviolet quencher.

12. The photocatalytic fiber having a core-shell structure according to claim 11, characterized in that, The ultraviolet absorber at least includes a benzophenone-based ultraviolet absorber or a benzotriazole-based ultraviolet absorber, the ultraviolet quencher includes a metal complex, and the free radical scavenger includes a hindered amine-based free radical scavenger.

13. A method for preparing a photocatalytic fiber having a core-shell structure as described in any one of claims 1-12, characterized in that, It includes the following steps: S1. Pulverize the synthetic resin by the air flow pulverization method to obtain a synthetic resin powder; S2. Mix the photocatalyst with the synthetic resin powder obtained in step S1 evenly to obtain a mixed powder; S3. Make the mixed powder obtained in step S2 into a photocatalyst masterbatch; S4. Use the photocatalyst masterbatch obtained in step S3 as the cortex raw material and the synthetic resin containing a light stabilizer as the core layer raw material to perform skin-core composite spinning to obtain a photocatalyst fiber with a skin-core structure; Among them, the type of synthetic resin used in step S1 is the same as or different from the type of synthetic resin used in the core layer raw material in step S4; In step S1, the air flow pulverization method uses a low-temperature cryogenic air flow pulverization process, the air flow speed for pulverizing the synthetic resin is 500-700 m / s, the low-temperature pulverization temperature is -20 to -150 °C, and the particle size of the obtained synthetic resin powder is controlled to be 10-20 μm; In step S2, the photocatalyst is in powder form with a particle size of 40-60 nm; a high-speed mixer is used to mix the synthetic resin powder and the photocatalyst. Specifically, it includes the following steps: S21. Heat the high-speed mixer to 60-70 °C; S22. Add the synthetic resin powder obtained in step S1 to the high-speed mixer, and the high-speed mixer disperses at 300-500 r / min for 3-5 min, and then rises to 800-1000 r / min and continues to disperse for 1-3 min; S23. Add photocatalyst into a high-speed mixer. Start the high-speed mixer. After the rotational speed stabilizes at 300 - 500 r / min, increase it to 800 - 1000 r / min and continuously operate for 5 - 10 min to mix the photocatalyst with the synthetic resin powder to obtain a mixed powder.

14. The preparation method of the photocatalytic fiber according to claim 13, characterized in that, The low-temperature grinding temperature is -60 to -120 °C.

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