Antibacterial lyocell fiber and preparation method and application thereof

Abstract

The application provides antibacterial lyocell fibers and a preparation method and application thereof, and belongs to the technical field of textile materials and functional regenerated cellulose fibers. The application takes an aqueous extract powder of wormwood, cyclodextrin and a polycarboxylic acid crosslinking agent as raw materials, obtains crosslinked inclusion particles through an inclusion reaction and a crosslinking reaction, dissolves cellulose pulp in an NMMO aqueous solution for dehydration and concentration, adds the crosslinked inclusion particles, sprays the obtained antibacterial lyocell spinning dope, and then passes through a gas gap into a coagulation bath to be coagulated and formed into a nascent fiber, and through post-processing, the antibacterial lyocell fiber is obtained. The application constructs organic polysaccharide crosslinked inclusion particles which are basically insoluble in water but stably dispersed in a high-concentration NMMO aqueous solution, realizes fixation and slow release of active components of wormwood, improves the water washing retention rate and antibacterial durability of the active components of wormwood in the finished fiber, and inhibits the migration of the active components of wormwood to the NMMO coagulation bath, thereby reducing the total organic carbon content in the coagulation bath.

Description

Technical Field

[0001] This invention relates to the field of textile materials and functional regenerated cellulose fiber technology, and in particular to an antibacterial lyocell fiber, its preparation method and application. Background Technology

[0002] Lyocell fiber is a novel type of regenerated cellulose fiber produced from natural cellulose pulp using an N-methylmorpholine-N-oxide (NMMO) solvent system and a dry-jet wet-spinning process. This type of fiber combines the moisture-wicking, breathable, and skin-friendly properties of natural fibers with the high strength and modulus of synthetic fibers. Furthermore, the NMMO solvent can be efficiently recovered, and the fiber itself is biodegradable, making it considered an environmentally friendly green fiber with wide applications in clothing, home textiles, and hygiene products.

[0003] With increasing emphasis on health and hygiene, lyocell fibers and textiles with multiple functions such as antibacterial, anti-mite, soothing, and health benefits have attracted widespread attention. The natural origin and relatively good safety of plant-based active ingredients are one of the important ways to endow lyocell fibers with multiple functions. Artemisia argyi, a traditional medicinal plant, is rich in polyphenols, flavonoids, water-soluble components, and volatile essential oils, possessing certain antibacterial, anti-inflammatory, and soothing effects. Therefore, developing functional lyocell fibers containing artemisia argyi active ingredients has promising application prospects.

[0004] In existing technologies, to achieve the antibacterial or health-promoting functions of lyocell fibers, patent CN118166439A proposes to formulate plant extracts such as rhubarb, rosemary, and artemisia into dispersions or emulsions, which are then directly blended with NMMO-cellulose solutions for spinning. However, this method is relatively simple, and because the plant extracts are mostly polar small molecules, they easily migrate to the aqueous coagulation bath along the concentration gradient, resulting in limited active ingredient content, poor wash resistance, and difficulty in maintaining antibacterial properties in the finished lyocell fibers for a long time. Simultaneously, it significantly increases the organic pollution load of the NMMO coagulation bath; patents CN112458564A and CN11... 7966289A utilizes mesoporous silica, porous starch, etc. to construct porous molecular nests, or uses modified starch, hydroxypropyl cellulose, etc. to encapsulate plant extracts to prepare microcapsules, which are then introduced into NMMO-cellulose solution for spinning. Although this technology improves the retention rate of active ingredients in fibers to a certain extent, it requires multiple organic solvent treatments and coupling reactions, making the process complex. In addition, the compatibility between the inorganic carrier and the cellulose matrix is ​​limited, which may have an adverse effect on the spinning rheological properties and fiber mechanical properties. Furthermore, there is still a problem of plant active ingredients migrating to the coagulation bath, causing pollution to the NMMO recovery system.

[0005] Existing lyocell fibers containing Artemisia argyi primarily utilize ethanol extraction or supercritical CO2 methods to obtain Artemisia argyi essential oil or organic phase extracts, which are then released sustainably through microencapsulation and other methods. However, there are few reports on the behavior and fixation mechanisms of aqueous Artemisia argyi extracts, mainly composed of polyphenols and flavonoids, particularly in NMMO-cellulose systems. Aqueous Artemisia argyi extracts are highly polar and have small molecular weights; if added directly to the spinning solution, they readily migrate to the coagulation bath, resulting in a low effective content in the fiber.

[0006] In summary, existing lyocell fibers containing plant-based active ingredients generally suffer from the following common problems: small-molecule plant-based active ingredients are easily lost during spinning and washing, resulting in low content of effective ingredients and poor antibacterial durability in the fibers; a large amount of plant-based active ingredients migrate to the aqueous phase coagulation bath during spinning, exacerbating organic pollution in the NMMO coagulation bath and increasing the burden of recycling; some solutions introduce inorganic carriers or organic small-molecule fixatives, which are complex in process and lack environmental friendliness and safety.

[0007] Therefore, there is an urgent need for a carrier structure and fiber preparation method that is highly compatible with the NMMO-cellulose system, can effectively immobilize the aqueous extract of Artemisia argyi and inhibit its migration to the coagulation bath, so as to obtain antibacterial lyocell fibers with both excellent antibacterial durability and green process characteristics. Summary of the Invention

[0008] The purpose of this invention is to provide an antibacterial lyocell fiber, its preparation method and application, wherein the antibacterial lyocell fiber has high antibacterial durability and a significantly reduced increase in total organic carbon content in the NMMO coagulation bath.

[0009] To achieve the above-mentioned objectives, the present invention provides the following technical solution: This invention provides a method for preparing antibacterial lyocell fiber, comprising the following steps: Artemisia argyi aqueous extract powder, cyclodextrin and water were mixed and subjected to inclusion reaction. The resulting inclusion solution was spray-dried to obtain inclusion powder. The inclusion powder was dispersed in an aqueous solution containing a polycarboxylic acid crosslinking agent and subjected to pre-drying, crosslinking reaction and then pulverization and classification to obtain cyclodextrin / artemisia argyi aqueous extract crosslinked inclusion particles. Cellulose pulp was mixed with an aqueous solution of N-methylmorpholine-N-oxide and then dehydrated and concentrated to obtain an NMMO-cellulose solution. The cross-linked inclusion particles of the cyclodextrin / Artemisia argyi aqueous extract were mixed with the NMMO-cellulose solution, stirred, and vacuum degassed to obtain the antibacterial lyocell fiber spinning solution. The antibacterial lyocell fiber spinning solution is spun into fibers, and the resulting spun fibers are fed into a coagulation bath through an air gap to solidify and form fibers. The resulting nascent fibers are then washed, oiled, dried, and wound sequentially to obtain antibacterial lyocell fibers.

[0010] Preferably, the cyclodextrin includes β-cyclodextrin, hydroxypropyl-β-cyclodextrin, or a mixture of β-cyclodextrin and hydroxypropyl-β-cyclodextrin; The inclusion reaction is carried out at a temperature of 40-60°C for 2-6 hours. The spray drying process involves an inlet air temperature of 150-190℃, an outlet air temperature of 60-90℃, and a drying time of 10-60 minutes.

[0011] Preferably, the polycarboxylic acid crosslinking agent includes one or more of citric acid, 1,2,3,4-butanetetracarboxylic acid, succinic acid, and maleic acid; The pre-drying temperature is 80~110℃, and the time is 10~60 min; The crosslinking reaction is carried out at a temperature of 130~180℃ for a time of 10~60 min; The cross-linked inclusion particles have a particle size of 0.2~1.5 μm.

[0012] Preferably, the mass fraction of the N-methylmorpholine-N-oxide aqueous solution is 50-75%; The dehydration and concentration process is carried out at a pressure of 5-30 kPa, a temperature of 80-120℃, and a time of 30-60 min. The mass fraction of cellulose in the NMMO-cellulose solution is 8-15%; The NMMO-cellulose solution contains 75-82% NMMO by mass and has a viscosity of 1000-3000 cP.

[0013] Preferably, the mass of the cross-linked inclusion particles of the cyclodextrin / Artemisia argyi aqueous extract is 0.5-10% of the mass of cellulose in the NMMO-cellulose solution; The stirring speed is 50~300 r / min, the temperature is 60~100℃, and the time is 0.5~3h; The vacuum degassing time is 10~60 min, and the pressure is 5~30 kPa.

[0014] Preferably, the length of the air gap is 5~20 mm; The coagulation bath solution is water or an aqueous solution of N-methylmorpholine-N-oxide with a mass fraction of 10-15%; The solidification temperature is 5~25℃, the stretching ratio is 2.0~5.0, and the time is 2~10 s.

[0015] Preferably, the surface of the cyclodextrin / Artemisia argyi aqueous extract cross-linked inclusion particles is coated with a water-soluble polymer; the water-soluble polymer includes one or more of polyethylene glycol, polyvinylpyrrolidone, and carboxymethyl cellulose salt.

[0016] Preferably, the surface coating includes the following steps: The cyclodextrin / artemisia aqueous extract cross-linked inclusion particles, water-soluble polymers and water were mixed and spray-dried to obtain cyclodextrin / artemisia aqueous extract cross-linked inclusion particles with water-soluble polymers coated on the surface. The mass ratio of the cross-linked inclusion particles of the cyclodextrin / Artemisia argyi aqueous extract to the water-soluble polymer is (10~30):1; The spray drying process involves an inlet air temperature of 140-180℃, an outlet air temperature of 70-90℃, and a drying time of 15-45 minutes.

[0017] This invention provides antibacterial lyocell fibers prepared by the above-described method. The antibacterial lyocell fibers use cellulose as a matrix, and cross-linked inclusion particles are uniformly distributed in a dotted or island-like pattern in the cross-section of the antibacterial lyocell fibers. The D of the cross-linked inclusion particles... 90 <5 μm.

[0018] This invention provides the application of the above-mentioned antibacterial lyocell fiber in intimate apparel fabrics, home textiles, or hygiene products.

[0019] The beneficial effects of this invention are: This invention uses Artemisia argyi aqueous extract powder, cyclodextrin, and polycarboxylic acid crosslinking agents as raw materials to prepare cyclodextrin / Artemisia argyi aqueous extract crosslinked inclusion particles through inclusion and crosslinking reactions. The organic polysaccharide network carrier constructed by cyclodextrin inclusion and polycarboxylic acid crosslinking can lock the small molecule active ingredients in Artemisia argyi aqueous extract inside the crosslinked inclusion particles, making them stable in the NMMO-cellulose system. During dry-jet wet spinning, only a small amount of soluble components migrate to the coagulation bath. Compared with untreated or other carrier methods, the amount of Artemisia argyi active ingredients precipitated in the NMMO coagulation bath is significantly reduced, and the increase in total organic carbon (TOC) in the coagulation bath is significantly reduced. This invention uses cyclodextrin and polycarboxylic acid as the main carrier components, without introducing inorganic powders such as mesoporous silica, and without using potentially harmful fixatives such as bisphenol A type epoxy resin and isocyanate. The carrier components have better safety and biocompatibility, and are highly compatible with the Lyocell green solvent system. The cyclodextrin / Artemisia argyi aqueous extract crosslinked inclusion particles prepared by this invention are micron-sized organic particles that are basically insoluble in water at 25°C, and also insoluble in an aqueous solution of N-methylmorpholine-N-oxide with a mass fraction of 50-75%. They can form a stable dispersion system in an aqueous solution of N-methylmorpholine-N-oxide with a mass fraction of 75-82%, are not prone to agglomeration, and have little impact on the viscosity, filtration, and spinneret stability of the spinning solution. The resulting fibers maintain excellent mechanical properties and textile processing properties, making them suitable for industrial production.

[0020] This invention involves dissolving cellulose pulp in an NMMO aqueous solution for dehydration and concentration, then adding cross-linked inclusion particles to obtain an antibacterial lyocell spinning solution. The antibacterial lyocell spinning solution is extruded through a spinneret and coagulated in a coagulation bath via an air gap. The resulting nascent fibers are then washed, oiled, dried, and wound sequentially to obtain antibacterial lyocell fibers. The antibacterial lyocell fibers obtained by this invention have cellulose as the matrix, with cross-linked inclusion particles evenly distributed in a dotted or island-like pattern in the fiber cross-section, which can slowly release the active ingredients of Artemisia argyi during fiber use and washing. Compared with directly adding Artemisia argyi powder or only using cyclodextrin inclusion systems, the residual rate of Artemisia argyi characteristic components in the fiber of the present invention is not less than 90% of the initial content after 20 simulated household washings, and the antibacterial rate against Staphylococcus aureus and Escherichia coli is not less than 95%. Under the same spinning conditions as the control fiber without cross-linked inclusion particles, the increase in total organic carbon content in the N-methylmorpholine-N-oxide coagulation bath caused by Artemisia argyi active ingredients is reduced by at least 80%, achieving long-lasting antibacterial properties.

[0021] This invention constructs cross-linked inclusion particles of organic polysaccharides that are essentially insoluble in water but can be stably dispersed in high-concentration NMMO aqueous solutions. This enables the effective immobilization and sustained release of small-molecule active ingredients from Artemisia argyi aqueous extracts, thereby significantly improving the water wash resistance and antibacterial durability of Artemisia argyi active ingredients in finished lyocell fibers. During the spinning process, it significantly inhibits the migration of Artemisia argyi active ingredients to the NMMO coagulation bath, resulting in a significant reduction in the level of related organic contamination in the coagulation bath, which is beneficial for the closed-loop circulation and stable operation of the NMMO solvent.

[0022] The raw materials for this invention are readily available. Starting with conventional water-extracted Artemisia argyi powder, the process can be promoted through steps such as cyclodextrin inclusion, polycarboxylic acid crosslinking, and melt dispersion. The process conditions are mild and it is easy to introduce into existing lyocell fiber production lines, showing good prospects for industrial application. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the preparation method of the antibacterial lyocell fiber of the present invention; Figure 2 The microstructure of the Artemisia argyi aqueous extract / cyclodextrin cross-linked inclusion particles in Example 1 of this invention; Figure 3 The image shows the microstructure of the antibacterial lyocell fiber prepared in Example 1 of this invention. Detailed Implementation

[0024] This invention provides a method for preparing antibacterial lyocell fiber, comprising the following steps: Artemisia argyi aqueous extract powder, cyclodextrin and water were mixed and subjected to inclusion reaction. The resulting inclusion solution was spray-dried to obtain inclusion powder. The inclusion powder was dispersed in an aqueous solution containing a polycarboxylic acid crosslinking agent and subjected to pre-drying, crosslinking reaction and then pulverization and classification to obtain cyclodextrin / artemisia argyi aqueous extract crosslinked inclusion particles. Cellulose pulp was mixed with an aqueous solution of N-methylmorpholine-N-oxide and then dehydrated and concentrated to obtain an NMMO-cellulose solution. The cyclodextrin / Artemisia argyi aqueous extract cross-linked inclusion particles were mixed with NMMO-cellulose solution, stirred, and vacuum degassed to obtain antibacterial lyocell fiber spinning solution. The antibacterial lyocell fiber spinning solution is spun into fibers, and the resulting spun fibers are coagulated in a coagulation bath through an air gap. The resulting nascent fibers are then washed, oiled, dried, and wound sequentially to obtain antibacterial lyocell fibers.

[0025] In this invention, unless otherwise specified, all raw materials required for preparation are commercially available products well known to those skilled in the art.

[0026] The present invention preferably involves mixing cyclodextrin with water, adding Artemisia argyi aqueous extract powder to the resulting cyclodextrin aqueous solution, performing an inclusion reaction, followed by ultrasonic dispersion, and spray drying the resulting inclusion solution to obtain inclusion powder; dispersing the inclusion powder in an aqueous solution containing a polycarboxylic acid crosslinking agent, pre-drying, and then performing a crosslinking reaction to obtain a brittle crosslinked film; pulverizing the crosslinked film and performing air classification to obtain cyclodextrin / Artemisia argyi aqueous extract crosslinked inclusion particles.

[0027] In this invention, the cyclodextrin preferably includes β-cyclodextrin, hydroxypropyl-β-cyclodextrin, or a mixture of β-cyclodextrin and hydroxypropyl-β-cyclodextrin, and more preferably β-cyclodextrin or hydroxypropyl-β-cyclodextrin.

[0028] In this invention, the preparation process of the Artemisia argyi aqueous extract powder preferably includes the following steps: pulverizing the Artemisia argyi herb and passing it through a 60-mesh sieve, then extracting it with water, filtering, concentrating it, and spray drying it to obtain the Artemisia argyi aqueous extract powder. The Artemisia argyi aqueous extract powder has water-soluble polyphenols and flavonoids as the main active ingredients. The mass of the water is preferably 10 times the mass of the Artemisia argyi herb. The concentration pressure is preferably 10~30 kPa, the time is preferably 1~3 h, and the concentration is preferably concentrated to 1 / 5 of the original volume. The inlet air temperature of the spray drying is preferably 150~180℃, the outlet air temperature is preferably 75~90℃, and the time is preferably 10~60 min.

[0029] In this invention, the temperature of the inclusion reaction is preferably 40~60℃, more preferably 50~60℃, and the time is preferably 2~6 h, more preferably 3~6 h.

[0030] In this invention, the ultrasonic dispersion time is preferably 20 min.

[0031] In this invention, when the above-mentioned inclusion solution is spray-dried, the inlet air temperature of the spray drying is preferably 150~190℃, more preferably 160~190℃, the outlet air temperature is preferably 60~90℃, more preferably 60~85℃, and the time is preferably 10~60 min, more preferably 30~40 min.

[0032] In this invention, the polycarboxylic acid crosslinking agent preferably includes one or more of citric acid, 1,2,3,4-butanetetracarboxylic acid, succinic acid and maleic acid, and more preferably citric acid or 1,2,3,4-butanetetracarboxylic acid.

[0033] In this invention, the pre-drying temperature is preferably 80~110℃, more preferably 90~110℃, and the time is preferably 10~60 min, more preferably 30 min.

[0034] In this invention, the temperature of the crosslinking reaction is preferably 130~180℃, more preferably 160~180℃, and the time is preferably 10~60 min, more preferably 20~60 min; under these conditions, crosslinking is carried out to allow the polycarboxylic acid and the cyclodextrin hydroxyl group to undergo esterification crosslinking.

[0035] In this invention, the particle size of the cross-linked inclusion particles of cyclodextrin / Artemisia argyi aqueous extract is preferably 0.2~1.5 μm.

[0036] In this invention, the cyclodextrin / Artemisia argyi aqueous extract crosslinked inclusion particles are preferably coated with a water-soluble polymer on their surface. Coating the surface of the crosslinked inclusion particles with a water-soluble polymer can form a solubilizing interface layer, which improves the wettability of the particles in the NMMO cellulose system. It also inhibits particle aggregation through steric hindrance and electrostatic repulsion, ensuring uniform dispersion in the spinning solution. At the same time, this coating layer acts as a mass transfer barrier layer for the outward diffusion of active ingredients, forming a multi-level constraint structure with the internal crosslinking network of the particles. This prolongs the migration path of Artemisia argyi active ingredients, reduces their precipitation rate into the coagulation bath, and enhances the interfacial bonding between the particles and the cellulose matrix, thereby improving the fiber retention rate of active ingredients and the sustained-release stability of the fiber.

[0037] In this invention, the water-soluble polymer preferably includes one or more of polyethylene glycol, polyvinylpyrrolidone, and carboxymethyl cellulose salt, and more preferably polyvinylpyrrolidone. The coating material selected in this invention has excellent compatibility with the NMMO spinning system and cellulose matrix, and will not change the viscosity or filterability of the spinning solution, ensuring stable spinning. The particles are evenly dispersed without stress concentration, which does not affect the fiber mechanics and textile processing performance. It can also reduce the increase of organic carbon in the coagulation bath, which is beneficial to the recycling of NMMO.

[0038] In this invention, the coating preferably includes the following steps: mixing cyclodextrin / artemisia aqueous extract cross-linked inclusion particles with water, stirring and dispersing at 35~60℃ for 10~30 min, adding an aqueous solution containing water-soluble polymers, stirring evenly, and then spray drying at an inlet air temperature of 140~180℃ and an outlet air temperature of 70~90℃ for 15~45 min to obtain cyclodextrin / artemisia aqueous extract cross-linked inclusion particles with water-soluble polymers coated on the surface.

[0039] In this invention, the mass ratio of the cyclodextrin / Artemisia argyi aqueous extract cross-linked inclusion particles to the water-soluble polymer in the aqueous solution containing the water-soluble polymer is preferably (10~30):1, and more preferably 20:1.

[0040] The present invention preferably involves mixing cellulose pulp with an aqueous solution of N-methylmorpholine-N-oxide (NMMO) and then dehydrating and concentrating the mixture to obtain an NMMO-cellulose solution. The core purpose of the dehydration and concentration in this invention is to adjust the ratio of NMMO to water by removing free water from the system, thereby providing a suitable solvent environment for the full dissolution of cellulose.

[0041] In this invention, the mass fraction of the NMMO aqueous solution is preferably 50-75%, and more preferably 60-75%.

[0042] In this invention, the pressure of dehydration and concentration is preferably 5~30 kPa, more preferably 10~20 kPa, the temperature is preferably 80~120℃, more preferably 90~110℃, and the time is preferably 30~60 min, more preferably 40~50 min. Under the specific dehydration and concentration parameters of this invention, precise control is achieved to remove only water without losing cellulose. Only the mass fraction of NMMO in the system is changed, and cellulose remains in the system without loss or degradation, laying a uniform and stable foundation for the subsequent preparation of spinning solution.

[0043] In this invention, the mass fraction of cellulose in the NMMO-cellulose solution is preferably 8-15%, more preferably 10-12%.

[0044] In this invention, the mass fraction of NMMO in the NMMO-cellulose dissolving solution is preferably 75-82%, more preferably 79%; within this range, NMMO molecules form a chain-like hydrogen bond structure through water molecules, retaining the strong polarity of NO bonds, and can efficiently dissolve cellulose.

[0045] In this invention, the viscosity of the NMMO-cellulose solution is preferably 1000~3000 cP, more preferably 1500~2500 cP.

[0046] In this invention, the cross-linked inclusion particles of the above-mentioned cyclodextrin / artemisia argyi aqueous extract are mixed with the above-mentioned NMMO-cellulose solution, stirred, and then vacuum degassed to obtain the antibacterial lyocell fiber spinning solution.

[0047] In this invention, the mass of the cyclodextrin / Artemisia argyi aqueous extract cross-linked inclusion particles is preferably 0.5-10% of the mass of cellulose in the NMMO-cellulose solution, and more preferably 3-5%.

[0048] In this invention, the stirring speed is preferably 50~300 r / min, more preferably 100~250 r / min, the temperature is preferably 60~100℃, more preferably 80~100℃, and the time is preferably 0.5~3 h, more preferably 1.5~3 h.

[0049] In this invention, the vacuum degassing time is preferably 10-60 min, more preferably 30-60 min, and the pressure is preferably 5-30 kPa, more preferably 20 kPa.

[0050] In this invention, the above-mentioned antibacterial lyocell spinning fiber dope is filtered through a 25μm filter screen and then fed into a spinneret assembly via a metering pump. The spinneret has 100 spinneret holes with a diameter of 60~120μm and a spinneret speed of 5~20m / min to obtain a spun fine stream. The spun fine stream is then fed into a coagulation bath through an air gap to solidify and form the nascent fiber. The resulting nascent fiber is then washed, oiled, dried, and wound sequentially to obtain antibacterial lyocell fiber.

[0051] In this invention, the length of the air gap is preferably 5 to 20 mm, and more preferably 10 to 20 mm.

[0052] In this invention, the coagulation bath is preferably water or an aqueous solution of N-methylmorpholine-N-oxide with a mass fraction of 10-15%, and more preferably an aqueous solution of N-methylmorpholine-N-oxide with a mass fraction of 12-15%.

[0053] In this invention, the solidification temperature is preferably 5~25℃, more preferably 15~25℃, the draw ratio is preferably 2.0~5.0, more preferably 2.0, and the time is preferably 2~10 s, more preferably 5~8 s.

[0054] In this invention, the solvent used for washing is soft water at 50°C, the washing is preferably a 3-6 stage countercurrent washing, the bath ratio of each stage of washing is preferably 1:10-1:20, the washing time of each stage is preferably 0.5-3 min, and the total washing time is preferably 5-20 min; the washing is preferably carried out until the NMMO content drops to <1 wt%.

[0055] In this invention, the oiling agent preferably comprises, by weight, 10-40 parts of synthetic ester lubricant, 5-25 parts of nonionic emulsifier, 2-15 parts of antistatic agent, 0-10 parts of silicone softener, and 0-10 parts of other additives; the oiling agent is diluted to a 0.5-3.0 wt% aqueous solution and applied to the fiber surface by means of an oil roller or spray.

[0056] In this invention, the synthetic ester lubricant preferably includes one or more of fatty acid low-carbon alcohol esters, fatty acid polyol esters, diesters, and polyester lubricants, and is more preferably isopropyl fatty acid esters, trimethylolpropane fatty acid esters, pentaerythritol fatty acid esters, or adipate diester lubricants; the isopropyl fatty acid ester is preferably isopropyl stearate, the trimethylolpropane fatty acid ester is preferably trimethylolpropane tristearate, the pentaerythritol fatty acid ester is preferably pentaerythritol tetrastearate, and the adipate diester lubricant is preferably diisooctyl adipate.

[0057] In this invention, the nonionic emulsifier preferably includes one or more of fatty alcohol polyoxyethylene ether (AEO-9), Tween-40 and Tween-85, and more preferably AEO-9.

[0058] In this invention, the antistatic agent preferably includes one or more of quaternary ammonium salt type antistatic agents, phosphate ester type antistatic agents, sulfonate type antistatic agents, and polyether type antistatic agents, and is more preferably a fatty alcohol quaternary ammonium salt antistatic agent or a polyether modified antistatic agent. The fatty alcohol quaternary ammonium salt antistatic agent is preferably hexadecyltrimethylammonium chloride (CTAC), and the polyether modified antistatic agent is preferably a polyoxyethylene polyoxypropylene ether block copolymer.

[0059] In this invention, the silicone softener preferably includes one or more of polydimethylsiloxane emulsion, amino-modified silicone oil emulsion, hydroxyl silicone oil emulsion, and polyether-modified silicone oil emulsion. The polydimethylsiloxane emulsion is preferably a polydimethylsiloxane emulsion with a solid content of 30%, and the amino-modified silicone oil emulsion is preferably an aminopropyltriethoxysilane-modified silicone oil emulsion with a solid content of 30%.

[0060] In this invention, the other additives preferably include one or more of the following: antifoaming agents, preservatives, pH adjusters, dispersing stabilizers, and antioxidants; the antifoaming agent is preferably polydimethylsiloxane, the preservative is preferably 5-chloro-2-methyl-4-isothiazolin-3-one, the pH adjuster is preferably triethanolamine, the dispersing stabilizer is preferably sodium carboxymethyl cellulose (CMC), and the antioxidant is preferably 2,6-di-tert-butyl-p-cresol (BHT).

[0061] In this invention, the drying temperature is preferably 80~120℃.

[0062] This invention provides antibacterial lyocell fibers prepared by the above-described method. Preferably, the antibacterial lyocell fibers use cellulose as a matrix, and cross-linked inclusion particles are uniformly distributed in a dotted or island-like pattern in the fiber cross-section. The D of the cross-linked inclusion particles... 90 Preferably <5μm.

[0063] This invention provides the application of the above-mentioned antibacterial lyocell fiber in intimate apparel fabrics, home textiles, or hygiene products.

[0064] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0065] The preparation method of the Artemisia argyi aqueous extract powder used in Examples 1-2 and Comparative Examples 1-2 includes the following steps: The dried Artemisia argyi herb was pulverized and passed through a 60-mesh sieve. Water, at a mass of 10 times the weight of the dried Artemisia argyi herb, was added and extracted under reflux at 90℃ for 2 hours. The extract was then filtered, and the filtrate was collected. The collected filtrate was concentrated to 1 / 5 of its original volume at 20 kPa and spray-dried for 30 minutes at an inlet air temperature of 160℃ and an outlet air temperature of 80℃ to obtain an aqueous extract powder of Artemisia argyi, containing a total polyphenol content of 18 wt%. The oils used in Examples 1-2 and Comparative Examples 1-2, by mass fraction, comprised the following components: 15 parts trimethylolpropane tristearate, 15 parts diisooctyl adipate, 10 parts AEO-9, 10 parts Tween-85, 6 parts hexadecyltrimethylammonium chloride, 4 parts polyoxyethylene polyoxypropylene ether block copolymer, 8 parts polydimethylsiloxane emulsion with a solid content of 30%, 1 part 5-chloro-2-methyl-4-isothiazolin-3-one, and 1 part 2,6-di-tert-butyl-p-cresol. Example 1

[0066] 200g of β-cyclodextrin was mixed with 800g of water. 40g of Artemisia argyi aqueous extract powder was added to the resulting β-cyclodextrin aqueous solution. The mixture was subjected to an inclusion reaction at 50℃ for 3 hours. After that, it was ultrasonically dispersed for 20 minutes. The resulting inclusion solution was spray-dried at an inlet air temperature of 160℃ and an outlet air temperature of 85℃ for 35 minutes to obtain 220g of inclusion powder. 200g of inclusion powder was dispersed in 400g of a 20wt% citric acid aqueous solution, stirred evenly, and then cast onto a stainless steel tray to a thickness of approximately 2mm. It was pre-dried at 90℃ for 30min, followed by a cross-linking reaction at 160℃ for 20min to obtain a brittle cross-linked film. The cross-linked film was pulverized and subjected to air classification to obtain an average particle size D. 50 Cross-linked inclusion particles of cyclodextrin / Artemisia argyi aqueous extract with a diameter of 1.2 μm; like Figure 1As shown, 120 kg of 67% coniferous-broadleaf mixed wood pulp was mixed with 880 kg of 60% N-methylmorpholine-N-oxide aqueous solution, and the mixture was dehydrated and concentrated at 110 °C and 20 kPa vacuum for 30 min to obtain NMMO-cellulose solution. The NMMO-cellulose solution contained 79 wt% NMMO and 12 wt% cellulose, and had a viscosity of 1800 cP. The cross-linked inclusion particles of cyclodextrin / artemisia annua aqueous extract were mixed with NMMO-cellulose solution and stirred at 200 r / min for 1.5 h at 80 °C. The mass of the cross-linked inclusion particles of cyclodextrin / artemisia annua aqueous extract was 3% of the mass of cellulose in the NMMO-cellulose solution. Then, the mixture was degassed at 20 kPa for 30 min to obtain the antibacterial lyocell fiber spinning solution. The antibacterial lyocell spinning solution was filtered through a 25μm filter and then fed into the spinneret assembly via a metering pump. The spinneret had 100 orifices with a diameter of 100 μm and a spinning speed of 10 m / min. The resulting spun yarn entered a 12% NMMO aqueous solution through a 10 mm air gap and solidified for 8 s at 15℃ and a draw ratio of 2.0 to form nascent fibers. The nascent fibers were then subjected to a 5-stage countercurrent washing process with soft water at 50℃. Each stage of the washing process had a liquor ratio of 1:15 and a washing time of 3 min, for a total washing time of 15 min. The washing process continued until the NMMO content dropped to <1 wt%. The fibers were then oiled with a 1 wt% oiling agent, dried with hot air at 80℃, and wound to obtain antibacterial lyocell fibers. Example 2

[0067] The only difference from Example 1 is: 200g of hydroxypropyl-β-cyclodextrin was mixed with 800g of water. 40g of Artemisia argyi aqueous extract powder was added to the resulting hydroxypropyl-β-cyclodextrin aqueous solution. The mixture was subjected to an inclusion reaction at 50℃ for 3 hours. After that, it was ultrasonically dispersed for 20 minutes. The resulting inclusion solution was spray-dried at an inlet air temperature of 160℃ and an outlet air temperature of 85℃ for 35 minutes to obtain 220g of inclusion powder. 200g of the inclusion powder was dispersed in 400g of a 20wt% aqueous solution of 1,2,3,4-butanetetracarboxylic acid. After stirring evenly, the mixture was cast onto a stainless steel tray to a thickness of approximately 2mm. It was pre-dried at 90℃ for 30min, followed by a crosslinking reaction at 160℃ for 20min to obtain a brittle crosslinked film. The crosslinked film was then pulverized and subjected to air classification to obtain an average particle size D. 50 Cross-linked inclusion particles of cyclodextrin / Artemisia argyi aqueous extract with a diameter of 1.2 μm; 100 g of cyclodextrin / Artemisia argyi aqueous extract cross-linked inclusion particles were added to 600 g of water and stirred and dispersed at 40℃ for 20 min. Then, 100 g of 5 wt% PVP K30 aqueous solution was added and stirred at 50℃ for 60 min. Subsequently, spray drying was carried out at an inlet air temperature of 160℃ and an outlet air temperature of 85℃ for 30 min to obtain PVP-coated cross-linked inclusion particles. like Figure 1 As shown, 120 kg of 67% coniferous-broadleaf mixed wood pulp was mixed with 880 kg of 60% N-methylmorpholine-N-oxide aqueous solution, and the mixture was dehydrated and concentrated at 110 °C and 20 kPa vacuum for 30 min to obtain NMMO-cellulose solution. The NMMO-cellulose solution contained 79 wt% NMMO and 12 wt% cellulose, and had a viscosity of 1800 cP. The above PVP-coated cross-linked inclusion particles were mixed with NMMO-cellulose solution and stirred at 200 r / min for 1.5 h at 80 °C. The mass of the PVP-coated cross-linked inclusion particles was 5% of the mass of cellulose in the NMMO-cellulose solution. Then, the mixture was degassed at 20 kPa for 30 min to obtain antibacterial lyocell fiber spinning solution. The antibacterial lyocell spinning solution was filtered through a 25μm filter and then fed into the spinneret assembly via a metering pump. The spinneret had 100 orifices with a diameter of 100 μm and a spinning speed of 10 m / min. The resulting spun yarn entered a 12% NMMO aqueous solution through a 10 mm air gap and solidified for 8 s at 15℃ and a draw ratio of 2.0 to form nascent fibers. The nascent fibers were then subjected to a 5-stage countercurrent washing process with soft water at 50℃. Each stage of the washing process had a liquor ratio of 1:15 and a washing time of 3 min, for a total washing time of 15 min. The washing process continued until the NMMO content dropped to <1 wt%. The fibers were then oiled with a 1 wt% oiling agent, dried with hot air at 80℃, and wound to obtain antibacterial lyocell fibers.

[0068] Comparative Example 1 The only difference from Example 1 is: Artemisia argyi aqueous extract powder does not undergo inclusion reaction or cross-linking reaction; With other parameters remaining unchanged, antibacterial Lyocell fibers were obtained.

[0069] Comparative Example 2 The only difference from Example 1 is: Artemisia argyi aqueous extract powder does not undergo cross-linking reaction; With other parameters remaining unchanged, antibacterial lyocell fibers were obtained.

[0070] Characterization and performance testing 1. Figure 2 The image shows the microstructure of the Artemisia argyi aqueous extract / cyclodextrin cross-linked inclusion particles prepared in Example 1 of this invention. The average particle size of the inclusion particles is 0.8 μm. Figure 3 The image shows the microstructure of the antibacterial lyocell fiber prepared in Example 1 of this invention. The fiber has an average diameter of 17.8 μm, and cross-linked inclusion particles of Artemisia argyi active ingredients can be observed dispersed in the cellulose matrix.

[0071] 2. (1) The antibacterial lyocell fibers prepared in Examples 1-2 and Comparative Examples 1-2 were subjected to 20 simulated household washings according to GB / T 8629-2017. The active ingredients of Artemisia argyi in the antibacterial lyocell fibers prepared in Examples 1-2 and Comparative Examples 1-2 were quantified by HPLC before and after the 20 simulated washings, with iso-eucin as a characteristic component. The results are shown in Table 1. Table 1. Changes in the content of active ingredients of Artemisia argyi and the antibacterial rate of fibers in Examples 1-2 and Comparative Examples 1-2 before and after 20 simulated washes. (2) Under the same spinning conditions and fiber yield, the total organic carbon (TOC) content in NMMO aqueous solution before and after spinning of Examples 1-2 and Comparative Examples 1-2 was determined respectively. The results are shown in Table 2. Table 2. TOC changes in NMMON aqueous solution before and after spinning of fibers from Examples 1-2 and Comparative Examples 1-2. In Comparative Examples 1-2, no inclusion reaction was performed during fiber preparation. The aqueous extract of Artemisia argyi was already in the coagulation bath during the preparation of antibacterial lyocell fibers. Therefore, the content of Artemisia argyi active ingredients in the prepared antibacterial lyocell fibers was very low before washing. Comparing Examples 1-2 and Comparative Examples 1-2 with Tables 1-2, it can be seen that the present invention, through the combination of cyclodextrin inclusion and polycarboxylic acid crosslinking, significantly improves the wash resistance retention rate of Artemisia argyi active ingredients in lyocell fibers, resulting in better antibacterial durability. At the same time, the increase in TOC in the coagulation bath is the lowest, which fully demonstrates that the antibacterial lyocell fibers prepared by the technical solution of the present invention have high antibacterial durability and a significant reduction in the increase of total organic carbon content in the NMMO coagulation bath.

[0072] As can be seen from the above embodiments, the present invention provides an antibacterial lyocell fiber, its preparation method and application. The present invention uses Artemisia argyi aqueous extract powder, cyclodextrin and polycarboxylic acid crosslinking agent as raw materials to prepare crosslinked inclusion particles through inclusion reaction and crosslinking reaction; cellulose pulp is dissolved in NMMO aqueous solution for dehydration and concentration, crosslinked inclusion particles are added, the obtained antibacterial lyocell spinning dope is spun and then placed in a coagulation bath for coagulation and shaping, and the obtained nascent fiber is post-treated to obtain antibacterial lyocell fiber; the present invention achieves the fixation and sustained release of Artemisia argyi active ingredients by constructing organic polysaccharide crosslinked inclusion particles that are basically insoluble in water and stably dispersed in high-concentration NMMO aqueous solution, thereby improving the water wash resistance retention rate and antibacterial durability of Artemisia argyi active ingredients in the finished fiber, and inhibiting the migration of Artemisia argyi active ingredients to the NMMO coagulation bath, thus significantly reducing the level of related organic pollution in the coagulation bath.

[0073] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing antibacterial lyocell fiber, characterized in that, Includes the following steps: Artemisia argyi aqueous extract powder, cyclodextrin and water were mixed and subjected to inclusion reaction. The resulting inclusion solution was spray-dried to obtain inclusion powder. The inclusion powder was dispersed in an aqueous solution containing a polycarboxylic acid crosslinking agent and subjected to pre-drying, crosslinking reaction and then pulverization and classification to obtain cyclodextrin / artemisia argyi aqueous extract crosslinked inclusion particles. Cellulose pulp was mixed with an aqueous solution of N-methylmorpholine-N-oxide and then dehydrated and concentrated to obtain an NMMO-cellulose solution. The cross-linked inclusion particles of the cyclodextrin / Artemisia argyi aqueous extract were mixed with the NMMO-cellulose solution, stirred, and vacuum degassed to obtain the antibacterial lyocell fiber spinning solution. The antibacterial lyocell fiber spinning solution is spun into fibers, and the resulting spun fine stream is passed through an air gap into a coagulation bath to solidify and form a shape. The resulting nascent fibers are then washed, oiled, dried, and wound in sequence to obtain antibacterial lyocell fibers. The crosslinking reaction is carried out at a temperature of 130~180℃ for a time of 10~60 min; The cross-linked inclusion particles of the cyclodextrin / Artemisia argyi aqueous extract have a particle size of 0.2~1.5μm; The mass fraction of NMMO in the NMMO-cellulose solution is 75-82%.

2. The preparation method according to claim 1, characterized in that, The cyclodextrin includes β-cyclodextrin, hydroxypropyl-β-cyclodextrin, or a mixture of β-cyclodextrin and hydroxypropyl-β-cyclodextrin; The inclusion reaction is carried out at a temperature of 40-60°C for 2-6 hours. The spray drying process involves an inlet air temperature of 150-190℃, an outlet air temperature of 60-90℃, and a drying time of 10-60 minutes.

3. The preparation method according to claim 2, characterized in that, The polycarboxylic acid crosslinking agent includes one or more of citric acid, 1,2,3,4-butanetetracarboxylic acid, succinic acid, and maleic acid. The pre-drying temperature is 80~110℃ and the time is 10~60min.

4. The preparation method according to claim 1, characterized in that, The mass fraction of the N-methylmorpholine-N-oxide aqueous solution is 50-75%; The dehydration and concentration process is carried out at a pressure of 5-30 kPa, a temperature of 80-120°C, and a time of 30-60 min. The mass fraction of cellulose in the NMMO-cellulose solution is 8-15%; The viscosity of the NMMO-cellulose solution is 1000~3000 cP.

5. The preparation method according to claim 1, characterized in that, The mass of the cross-linked inclusion particles of the cyclodextrin / Artemisia argyi aqueous extract is 0.5-10% of the mass of cellulose in the NMMO-cellulose solution; The stirring speed is 50~300 r / min, the temperature is 60~100℃, and the time is 0.5~3h; The vacuum degassing time is 10~60min, and the pressure is 5~30kPa.

6. The preparation method according to claim 1, characterized in that, The length of the air gap is 5~20mm; The coagulation bath is water or an aqueous solution of N-methylmorpholine-N-oxide with a mass fraction of 10-15%; The solidification temperature is 5~25℃, the stretching ratio is 2.0~5.0, and the time is 2~10s.

7. The preparation method according to claim 1, characterized in that, The surface of the cross-linked inclusion particles of the cyclodextrin / Artemisia argyi aqueous extract is coated with a water-soluble polymer; the water-soluble polymer includes one or more of polyethylene glycol, polyvinylpyrrolidone, and carboxymethyl cellulose salt.

8. The preparation method according to claim 7, characterized in that, The surface coating includes the following steps: The cyclodextrin / artemisia aqueous extract cross-linked inclusion particles, water-soluble polymers and water were mixed and spray-dried to obtain cyclodextrin / artemisia aqueous extract cross-linked inclusion particles with water-soluble polymers coated on the surface. The mass ratio of the cross-linked inclusion particles of the cyclodextrin / Artemisia argyi aqueous extract to the water-soluble polymer is (10~30):1; The spray drying process involves an inlet air temperature of 140-180°C, an outlet air temperature of 70-90°C, and a drying time of 15-45 minutes.

9. The antibacterial lyocell fiber prepared by the preparation method according to any one of claims 1 to 8, characterized in that, The antibacterial lyocell fiber uses cellulose as a matrix, and cross-linked inclusion particles are uniformly distributed in a dot-like or island-like pattern in the cross-section of the antibacterial lyocell fiber, wherein the D90 of the cross-linked inclusion particles is <5μm.

10. The use of the antibacterial lyocell fiber of claim 9 in the preparation of intimate apparel fabrics, home textiles or hygiene products.

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