TWI887601B - Moisture-absorbing and antibacterial functional fiber and its preparation method - Google Patents

Abstract

The moisture-absorbing and antibacterial functional fiber comprises a polymer matrix and functional components including plant extracts and modified chitosan nanopowder. The modified chitosan nanopowder is prepared by the following steps: (a) crushing shrimp shell blocks to obtain 1000 to 3000 mesh shrimp shell powder; (b) desalting the shrimp shell powder to obtain desalted shrimp shell powder, wherein the desalting comprises using at least 15 mL of an acidic treatment solution per 1 g of the shrimp shell powder; (c) deproteinizing the desalted shrimp shell powder to obtain deproteinized shrimp shell powder, wherein the deproteinization comprises At least 15 mL of alkaline treatment solution is used; (d) deproteinized shrimp shell powder is nano-formed to obtain chitosan nanopowder with a purity of 96% to 99% and an average particle size of 10 to 50 nm; (e) chitosan nanopowder is modified to obtain modified chitosan nanopowder, wherein the modification comprises reacting chitosan nanopowder dissolved in acetic acid with polyethylene glycol to obtain a purified product containing modified chitosan nanopowder.

Description

Moisture-absorbing and antibacterial functional fiber and its preparation method

The present invention relates to a functional fiber and a method for preparing the same, and in particular to a fiber having moisture absorption and antibacterial functions and a method for preparing the same.

Chitin-rich shrimp shells are currently the main raw material for the production of chitin in industry. However, the shrimp shells also contain proteins, inorganic salts (such as calcium carbonate), natural pigments and other substances. Therefore, the "acid-base method" is generally used to remove the protein and inorganic salts in the shrimp shells to purify chitin.

Since chitosan has very poor solubility in common solvents such as water, dilute acid, alkaline, ethanol or other organic solvents, it is not conducive to subsequent applications. In order to improve the problem of poor solubility of chitosan in common solvents, chitosan was previously subjected to a deacetylation reaction to obtain chitosan (also known as chitosan) with higher solubility in common solvents.

In the textile industry, functional fibers produced by adding chitosan derivatives and/or chitosan to spinning stock have excellent antibacterial properties and moisture absorption and quick-drying properties and are widely welcomed by the market. However, in the process of manufacturing such functional fibers, the chitosan derivatives and/or chitosan often have poor compatibility with the spinning stock, which leads to problems such as nozzle blockage during the spinning process. Furthermore, whether the chitosan derivatives and/or chitosan can be stably and evenly dispersed in the spinning stock so that the functional fibers produced have antibacterial properties and moisture absorption and quick-drying properties is also a point that needs to be considered in the manufacture of such functional fibers.

Therefore, an object of the present invention is to provide a moisture-absorbing and antibacterial functional fiber that solves at least one of the above problems.

Therefore, the moisture-absorbing and antibacterial functional fiber of the present invention comprises a polymer matrix and a functional component, wherein the functional component comprises a plant extract and a modified chitosan nanopowder. The modified chitosan nanopowder is prepared by the following steps (a) to (e): (a). Crushing shrimp shell blocks containing chitosan, an inorganic salt and a protein to obtain shrimp shell powder having a mesh size ranging from 1000 mesh to 3000 mesh and containing the chitosan, the inorganic salt and the protein; (b). Desalting the shrimp shell powder to remove the inorganic salt to obtain desalted shrimp shell powder containing the chitosan and the protein, wherein the desalting treatment includes using an acidic treatment liquid to remove the inorganic salt in the shrimp shell powder, and based on the amount of the shrimp shell powder being 1g, the amount of the acidic treatment liquid is at least 15mL; (c). The desalted shrimp shell powder is subjected to a deproteinization treatment to remove the protein, thereby obtaining a deproteinized shrimp shell powder containing the chitosan, wherein the deproteinization treatment includes removing the protein in the desalted shrimp shell powder using an alkaline treatment liquid in a microwave environment, and the amount of the alkaline treatment liquid is at least 15 mL based on the amount of the desalted shrimp shell powder being 1 g; (d). The deproteinized shrimp shell powder is subjected to a nano-treatment to obtain a chitosan nanopowder containing the chitosan, wherein the chitosan purity of the chitosan nanopowder is in the range of 96% to 99% and the average particle size is in the range of 10 nm to 50 nm; and (e) Modifying the chitosan nanopowder to obtain the modified chitosan nanopowder, wherein the modification includes dissolving the chitosan nanopowder in acetic acid and reacting with polyethylene glycol to obtain a product to be purified containing the modified chitosan nanopowder.

Another object of the present invention is to provide a method for preparing moisture-absorbing and antibacterial functional fibers.

Therefore, the method for preparing the moisture-absorbing and antibacterial functional fiber of the present invention comprises the following steps: (a). Crushing the shrimp shell blocks containing chitosan, inorganic salt and protein to obtain shrimp shell powder with a mesh size ranging from 1000 mesh to 3000 mesh and containing the chitosan, the inorganic salt and the protein; (b). Desalting the shrimp shell powder to remove the inorganic salt to obtain desalted shrimp shell powder containing the chitosan and the protein, wherein the desalting treatment includes using an acidic treatment liquid to remove the inorganic salt in the shrimp shell powder, and based on the amount of the shrimp shell powder being 1g, the amount of the acidic treatment liquid is at least 15mL; (c). The desalted shrimp shell powder is subjected to a deproteinization treatment to remove the protein, thereby obtaining a deproteinized shrimp shell powder containing the chitosan, wherein the deproteinization treatment includes removing the protein from the desalted shrimp shell powder using an alkaline treatment liquid in a microwave environment, and the amount of the alkaline treatment liquid is at least 15 mL based on the amount of the desalted shrimp shell powder being 1 g; (d). The deproteinized shrimp shell powder is subjected to a nano-treatment to obtain a chitosan nano powder containing the chitosan, wherein the chitosan purity of the chitosan nano powder is in the range of 96% to 99% and the average particle size is in the range of 10 nm to 50 nm; (e) Modifying the chitosan nanopowder to obtain modified chitosan nanopowder, wherein the modification comprises dissolving the chitosan nanopowder in acetic acid and reacting with polyethylene glycol to obtain a purified product containing the modified chitosan nanopowder; (f) Mixing the modified chitosan nanopowder, plant extract, glycerin and water and homogenizing to obtain a functional component; and (g) Mixing the functional component with a spinning stock solution and performing a spinning process to obtain a moisture-absorbing and antibacterial functional fiber.

The efficacy of the present invention is that: the method for preparing the moisture-absorbing antibacterial functional fiber of the present invention is that the mesh number range of the shrimp shell powder in the step (a) is designed to be 1000 mesh to 3000 mesh, and the inorganic salt in the shrimp shell powder is removed by using an acidic treatment liquid in an amount range of at least 15 mL (based on the amount of the shrimp shell powder being 1 g) in the step (b). In step (c), an alkaline treatment solution in an amount of at least 15 mL (based on 1 g of the desalted shrimp shell powder) is used to remove the protein in the desalted shrimp shell powder in a microwave environment, so that the chitosan purity of the chitosan nanopowder prepared in step (d) ranges from 96% to 99% and the average particle size ranges from 10 nm to 50 nm. Since the chitosan nanopowder has the characteristics of high chitosan purity and small average particle size, the functional component can be stably and evenly dispersed in the spinning stock solution in the subsequent step (g) and is not easily consumed in the spinning process, thereby making the prepared moisture-absorbing and antibacterial functional fiber of the present invention have excellent antibacterial properties and moisture-absorbing and quick-drying properties. Furthermore, through the step (e) and the step (f), the functional component prepared can also have good compatibility with the spinning stock solution, so the functional component will not cause problems such as blocking the nozzle during the spinning process, so that the moisture-absorbing antibacterial functional fiber of the present invention also has the advantages of good spinnability and not easy to break. In the moisture-absorbing antibacterial functional fiber of the present invention, the plant extract and the modified chitosan nanopowder are stably and uniformly dispersed in the polymer matrix, so that the moisture-absorbing antibacterial functional fiber of the present invention not only has excellent antibacterial properties and moisture absorption and quick-drying properties, but also has the advantages of excellent breaking strength, good spinnability and not easy to break.

《Moisture-absorbing and antibacterial functional fiber》

The moisture-absorbing antibacterial functional fiber of the present invention comprises a polymer matrix, and a functional component dispersed in the polymer matrix and including a plant extract and a modified chitosan nanopowder. The plant extract is covered on the surface of the modified chitosan nanopowder to form the functional component. In some embodiments of the present invention, the moisture-absorbing antibacterial functional fiber is 100wt%, for example, but not limited to, the content range of the polymer matrix is 70wt% to 90wt%, and the content range of the functional component is 10wt% to 30wt%. The functional component is 100wt%, for example, but not limited to, the content range of the plant extract is 10wt% to 30wt%, and the content range of the modified chitosan nanopowder is 70wt% to 90wt%.

The type of the polymer matrix does not need to be particularly limited, and any polymer that can be used to form fibers in the textile field is suitable for forming the polymer matrix. In some embodiments of the present invention, for example but not limited to, the polymer matrix is formed by viscose fiber spinning stock solution. The specific components contained in the viscose fiber spinning stock solution are, for example but not limited to, cellulose alpha (also known as α-cellulose).

In some specific embodiments of the present invention, the average particle size of the plant extract ranges from 20nm to 50nm. In some specific embodiments of the present invention, the plant extract is composed of an aloe vera extract, a tea extract, and a sarcandra extract. The aloe vera extract, the tea extract, and the sarcandra extract are all rich in active ingredients such as polysaccharides, polyphenols, and flavonoids, which can give the moisture-absorbing and antibacterial functional fiber better antibacterial and moisture-absorbing and quick-drying properties. More preferably, the weight ratio of the aloe vera extract, the tea extract, and the sarcandra extract is in the range of 1:2 to 5:3 to 4.

《Method for producing moisture-absorbing and antibacterial functional fibers》

The preparation method of the moisture-absorbing antibacterial functional fiber of the present invention comprises steps (a) to (g). Steps (a) to (g) are described in detail below.

Step (a)

In step (a), the shrimp shell block containing chitosan, the inorganic salt and the protein is crushed to obtain shrimp shell powder containing the chitosan, the inorganic salt and the protein. The specific method of the crushing treatment is not limited, as long as the mesh number of the shrimp shell powder is in the range of 1000 mesh to 3000 mesh.

In the step (a), the purpose of the pulverization treatment is to make the mesh number of the obtained shrimp shell powder range from 1000 mesh to 3000 mesh. If the mesh number of the shrimp shell powder is less than 1000 mesh, that is, the specific surface area of the shrimp shell powder is correspondingly small, the purity of the chitosan nanopowder prepared in the subsequent step (d) will be poor, and the loading rate of the plant extract in the functional component prepared in the subsequent step (f) will be poor, resulting in the moisture-absorbing and antibacterial functional fiber prepared in the step (g) having insufficient breaking strength and failing to meet the requirements for first-class products in the national standard GB/T 14463-2022 "Viscose Staple Fiber". If the mesh number of the shrimp shell powder is greater than 3000 mesh, the shrimp shell powder will be prone to agglomeration, causing the modified chitosan nanopowder prepared in the subsequent step (e) to be easily precipitated in the step (f), thereby causing the functional component to be unevenly dispersed in the spinning stock solution, ultimately resulting in poor antibacterial and moisture absorption quick-drying properties of the prepared moisture-absorbing and antibacterial functional fiber.

Step (b)

In the step (b), the shrimp shell powder is desalted to remove the inorganic salt, thereby obtaining desalted shrimp shell powder containing the chitosan and the protein. The desalting treatment includes using an acidic treatment liquid to remove the inorganic salt in the shrimp shell powder. The type of the acidic treatment liquid is not limited. Acidic chemicals known to be able to remove inorganic salts (such as calcium carbonate) from shrimp shells are suitable for use as the acidic treatment liquid used in the present invention. In some specific embodiments of the present invention, the acidic treatment solution comprises an acidic substance and a solvent, wherein the acidic substance is selected from hydrochloric acid, nitric acid, picric acid, tartaric acid, citric acid, apple acid, salicylic acid, caffeic acid or any combination thereof, and the solvent is selected from hydrochloric acid, nitric acid, water or any combination thereof. Considering the corrosiveness of the acidic treatment solution to the equipment and the safety of the operator, and ensuring that the desalination treatment has a better effect, preferably, the acidic substance is tartaric acid and citric acid and the solvent is hydrochloric acid. More preferably, in the acidic treatment solution, the weight ratio of the hydrochloric acid, the tartaric acid and the citric acid ranges from 1.5 to 3.5:2 to 3:0.5 to 1.5.

In the step (b), the amount of the acidic treatment solution is at least 15 mL, based on the amount of the shrimp shell powder being 1 g. If the amount of the acidic treatment solution is less than 15 mL, the inorganic salt in the shrimp shell powder cannot be completely removed, resulting in poor chitosan purity in the chitosan nanopowder prepared in the subsequent step (d), thereby resulting in poor antibacterial and moisture absorption and quick-drying properties of the moisture-absorbing antibacterial functional fiber prepared in the step (g). Furthermore, based on the amount of the shrimp shell powder being 1 g, further controlling the amount of the acidic treatment solution to be no more than 20 mL can also reduce the burden on the environment. Therefore, in some specific embodiments of the present invention, based on the amount of shrimp shell powder being 1 g, the amount of the acidic treatment solution is in the range of 15 mL to 20 mL.

Step (c)

In the step (c), the desalted shrimp shell powder is subjected to a deproteinization treatment to remove the protein, thereby obtaining the deproteinized shrimp shell powder containing the chitosan. The deproteinization treatment includes using an alkaline treatment liquid in a microwave environment to decompose the protein in the desalted shrimp shell powder into peptides or amino acids, thereby achieving the effect of removing the protein in the desalted shrimp shell powder. The microwave environment combined with the alkaline treatment liquid can more efficiently remove the protein in the desalted shrimp shell powder. If the desalted shrimp shell powder is not in the microwave environment, the protein in the desalted shrimp shell powder cannot be completely removed, resulting in poor chitosan purity of the chitosan nanopowder prepared in the subsequent step (d), thereby resulting in poor antibacterial and moisture absorption and quick-drying properties of the moisture-absorbing antibacterial functional fiber prepared in the step (g). Furthermore, in order to obtain the chitosan nanopowder with higher chitosan purity, preferably, in some specific embodiments of the present invention, the temperature range of the microwave environment is 40° C. to 50° C., and the power range is 160 to 320 W.

In step (c), the type of the alkaline treatment solution is not limited, and any alkaline chemical known to be able to decompose protein in shrimp shells is suitable for use as the alkaline treatment solution used in the present invention. In some specific embodiments of the present invention, the alkaline treatment solution comprises an alkaline substance and water, wherein the alkaline substance is selected from urea, potassium hydroxide, sodium hydroxide, triethylamine, 4-lutidine, or any combination thereof. The higher the pH value of the alkaline treatment solution, the better the effect of removing the protein from the desalted shrimp shell powder, but the peptide or the amino acid may be further decomposed by the alkaline treatment solution to produce substances with pungent odors such as hydrogen sulfide or ammonia, resulting in a bad smell of the chitosan nanopowder prepared in the subsequent step (d). Therefore, preferably, in some specific embodiments of the present invention, the pH value of the alkaline treatment solution ranges from 11 to 12, and the alkaline substance includes urea and sodium hydroxide. More preferably, in the alkaline substance, the weight ratio of the urea to the sodium hydroxide ranges from 2 to 3:1 to 2.

In the step (c), the amount of the alkaline treatment solution used is at least 15 mL, based on the amount of the desalted shrimp shell powder used being 1 g. If the amount of the alkaline treatment solution used is less than 15 mL, the protein in the desalted shrimp shell powder cannot be completely removed, resulting in poor chitosan purity in the chitosan nanopowder prepared in the subsequent step (d), thereby resulting in poor antibacterial and moisture absorption and quick-drying properties of the moisture-absorbing and antibacterial functional fiber prepared in the step (g). Furthermore, based on the amount of the desalted shrimp shell powder as 1g, the amount of the alkaline treatment solution is further controlled to be no more than 20mL, which can also reduce the burden on the environment. Therefore, in some specific embodiments of the present invention, based on the amount of the desalted shrimp shell powder as 1g, the amount of the alkaline treatment solution ranges from 15mL to 20mL.

Step (d)

In the step (d), the deproteinized shrimp shell powder is nano-processed to obtain chitosan nanopowder containing chitosan, and the average particle size of the chitosan nanopowder ranges from 10 nm to 50 nm.

In some specific embodiments of the present invention, the nano-treatment includes reacting the deproteinized shrimp shell powder with a hydrochloric acid aqueous solution to obtain an acidic crude product, adjusting the pH value of the acidic crude product to obtain a neutral crude product, and sequentially centrifuging, dialysis, ultrasonic vibration and concentrating the neutral crude product to obtain the chitosan nanopowder. The hydrochloric acid aqueous solution is used to expand, acidify and hydrolyze the deproteinized shrimp shell powder. Preferably, the volume molar concentration of the hydrochloric acid aqueous solution is in the range of 2M to 4M, so that the chitosan nanopowder has good particle size distribution uniformity. In some embodiments of the present invention, the centrifugal speed range is, for example but not limited to, 7000 rpm/min to 9000 rpm/min, and the centrifugal time range is, for example but not limited to, 10 minutes to 15 minutes. The power of the ultrasonic vibration is, for example but not limited to, 900 W, and the ultrasonic vibration time is, for example but not limited to, 30 minutes. The concentration is carried out at a temperature range of, for example but not limited to, 50° C. to 60° C.

It is worth mentioning that due to the specific mesh size design of the shrimp shell powder in step (a), the use of the acidic treatment solution in a specific dosage range in step (b) to remove the inorganic salt in the shrimp shell powder, and the use of the alkaline treatment solution in a specific dosage range in step (c) in combination with a microwave environment to remove the protein in the desalted shrimp shell powder, the chitosan purity of the prepared chitosan nanopowder ranges from 96% to 99%. Performing the step (b) once and the step (c) once is a purification procedure, preferably, the number of times of the purification procedure ranges from 3 to 4 times, which can make the chitosan nanopowder have a higher chitosan purity.

Step (e)

In the step (e), the chitosan nanopowder is subjected to a modification treatment to obtain a modified chitosan nanopowder. The modification treatment includes dissolving the chitosan nanopowder in acetic acid and reacting with polyethylene glycol to obtain a product to be purified containing the modified chitosan nanopowder. The purpose of reacting the chitosan nanopowder with the polyethylene glycol is to make the formed modified chitosan nanopowder have more polar groups than the chitosan nanopowder, which not only enables the modified chitosan nanopowder to have good compatibility with the plant extract in the subsequent step (f), thereby increasing the loading rate of the plant extract in the functional component, but also enables the moisture-absorbing and antibacterial functional fiber to have good antibacterial properties and moisture-absorbing and quick-drying properties. In order to extract the modified chitosan nanopowder from the purified material, in some specific embodiments of the present invention, the modification treatment further includes defoaming the purified material to obtain a defoamed mixture, dialyzing the defoamed mixture to obtain a dialysate, adjusting the pH value of the dialysate to 10 to 13 to precipitate a solid containing the modified chitosan nanopowder, and filtering the solid by vacuum extraction and washing with ethanol to remove the ethanol to obtain the modified chitosan nanopowder.

In the modification process, in order to allow the chitosan nanopowder and the polyethylene glycol to undergo a good deacetylation reaction, the chitosan nanopowder is fully dissolved by the acetic acid used as a solvent, so that the polyethylene glycol can maximally complete the deacetylation of the chitosan nanopowder dissolved by the acetic acid. The deacetylation reaction is to introduce the structure of the polyethylene glycol into the molecular chain of the chitosan nanopowder, which can effectively increase the distribution rate of the polar groups in the molecular chain of the chitosan nanopowder, that is, to increase the proportion of the hydrophilic groups in the molecular chain of the chitosan nanopowder, so that the modified chitosan nanopowder prepared from the chitosan nanopowder has better hydrophilicity. In addition, because the modified chitosan nanopowder has good hydrophilicity, the functional component prepared in the subsequent step (f) can have good compatibility with the spinning stock solution used in the step (g).

On the contrary, if the polyethylene glycol is not added, the functional component prepared in the subsequent step (f) will have poor compatibility with the spinning stock solution, resulting in poor spinnability, poor breaking strength (i.e., easy to break), poor antibacterial function, and poor moisture absorption and quick-drying function of the moisture-absorbing and antibacterial functional fiber prepared in the subsequent step (g).

Preferably, the weight ratio of the chitosan nanopowder to the polyethylene glycol is in the range of 1:0.1 to 0.3, the hydroxyl value of the polyethylene glycol is in the range of 102 mgKOH/g to 129 mgKOH/g, and the average relative molecular weight (Mr) is in the range of 900 to 1100. In some embodiments of the present invention, the reaction speed ranges from 500 rpm/min to 900 rpm/min, for example but not limited to, and the reaction time is at least 10 minutes, for example but not limited to.

Step (f)

In step (f), the modified chitosan nanopowder, the plant extract, the glycerol and the water are mixed and homogenized to obtain the functional component. The plant extract is coated on the surface of the modified chitosan nanopowder to form the functional component. In some specific embodiments of the present invention, the homogenization treatment includes mixing the modified chitosan nanopowder, the plant extract, the glycerol and the water and obtaining a homogenized solution under ultrasonic vibration, and then cooling, filtering and drying the homogenized solution in sequence to obtain the functional component.

In step (f), the plant extract serves to make the functional component and the spinning stock solution have good compatibility, so that the functional component will not cause problems such as blocking the nozzle during the spinning process, and the moisture-absorbing and antibacterial functional fiber of the present invention has the advantages of good spinnability and not easy to break.

In the step (f), the hydroxyl group of the glycerol forms hydrogen bonds with the polar groups in the modified chitosan nanopowder and the polar groups in the plant extract, which can not only reduce the loss of the modified chitosan nanopowder during the spinning process, but also improve the hydrophilicity of the functional component prepared, so that in the subsequent step (g), the functional component has good compatibility with the spinning stock solution used.

In the step (f), the water is used as a solvent and ultrasonic vibration is performed to uniformly disperse the modified chitosan nanopowder and the plant extract in the glycerol and the water, so that the functional component prepared has good compatibility in the used spinning stock solution. In some embodiments of the present invention, the temperature range of the ultrasonic vibration is, for example but not limited to, 30° C. to 50° C., the power range of the ultrasonic vibration is, for example but not limited to, 300W to 500W, and the time of the ultrasonic vibration is, for example but not limited to, at least 20 minutes.

〈Step (g)〉

In step (g), the functional component is mixed with a spinning stock solution and a spinning process is performed to obtain the moisture-absorbing antibacterial functional fiber. In some specific embodiments of the present invention, the spinning process is to wet-spin the spinning mixture obtained by mixing the functional component with the spinning stock solution.

In some specific embodiments of the present invention, the spinning stock solution is a viscose fiber spinning stock solution, and the specific components contained in the viscose fiber spinning stock solution include, for example, but not limited to, cellulose A. Preferably, the weight ratio of the functional component to the spinning stock solution is in the range of 1 to 3:7 to 10, so that the moisture-absorbing and antibacterial functional fiber has better antibacterial properties, better moisture-absorbing and quick-drying properties, and better breaking strength.

The spinning equipment and spinning conditions used in the wet spinning are not limited. In some specific embodiments of the present invention, the aperture range of the nozzle is, for example, but not limited to, 0.2 mm to 0.6 mm. In some specific embodiments of the present invention, the spinning speed range is, for example, but not limited to, 25 m/min to 35 m/min. In some specific embodiments of the present invention, the composition of the coagulation bath is, for example, but not limited to, sulfuric acid (H ₂ SO ₄ ), phosphoric acid (H ₃ PO ₄ ) and polyquaternium, and the weight ratio of the sulfuric acid, the phosphoric acid and the polyquaternium is, for example, but not limited to, 10 to 16:8 to 12:5 to 9, which can make the moisture-absorbing antibacterial functional fiber have better breaking strength. In some specific embodiments of the present invention, the temperature range of the coagulation bath is, for example but not limited to, 45° C. to 46° C. In some specific embodiments of the present invention, the wet spinning further includes post-treatment, such as but not limited to washing, desulfurization, bleaching, pickling, oiling and/or drying.

It is worth mentioning that, since the chitosan nanopowder has the characteristics of high chitosan purity and small average particle size, the functional component obtained in step (f) can be stably and evenly dispersed in the spinning stock solution and is not easily consumed in the spinning process, thereby making the moisture-absorbing and antibacterial functional fiber of the present invention have excellent antibacterial properties and moisture-absorbing and quick-drying properties.

The present invention will be further described with respect to the following embodiments, but it should be understood that the embodiments are only for illustration and description and should not be interpreted as limitations of the implementation of the present invention.

〈Implementation Example 1 〉

(a) providing shrimp shell blocks, wherein the shrimp shell blocks are prepared by washing discarded shrimp shells and drying them at a temperature of 50° C. for 6 hours. The shrimp shell blocks are crushed using a crusher (source: Weifang Jinghua Powder Engineering Equipment Co., Ltd.; model: JHMB2.2*0.5) to obtain shrimp shell powder with a mesh size of 2000 mesh.

(b) providing an acidic treatment solution formed by dissolving tartaric acid and citric acid in hydrochloric acid, wherein the weight ratio of the hydrochloric acid, the tartaric acid and the citric acid is 2:2.5:1. 500 g of the shrimp shell powder is mixed with 8000 mL of the acidic treatment solution to obtain an acidic mixture with a pH value of 1.5, and then the acidic mixture is stirred for 30 minutes using a stirring device (source: Henan Tiangang Environmental Protection Equipment Co., Ltd.; model: 80) at a temperature of 25° C. and a rotation speed of 100 rpm/min to remove inorganic salts (such as calcium carbonate) in the shrimp shell powder. After the stirring, the obtained product was filtered to obtain an acid filter cake, and the acid filter cake was continuously rinsed with distilled water until the pH value of the filtrate flowing out of the rinse was 7, thereby obtaining a first neutral filter cake. The first neutral filter cake was then dried at a temperature of 80° C. for 3 hours to obtain 375 g of desalted shrimp shell powder.

(c) providing an alkaline treatment solution formed by dissolving urea and sodium hydroxide in water, wherein the weight ratio of the urea to the sodium hydroxide is 2.5:1.5, and the total amount of the alkaline treatment solution is 100wt%, and the total content of the urea and the sodium hydroxide is 10wt%. 375g of the desalted shrimp shell powder is mixed with 6000mL of the alkaline treatment solution to obtain an alkaline mixture with a pH value of 12. Then, a microwave device (source: Qingdao Maiwei Microwave Chemical Equipment Co., Ltd.; model: MKX-H4G1A) is used to microwave the alkaline mixture for 10 minutes at a temperature of 45°C and a power of 220W to remove the protein in the desalted shrimp shell powder. After the microwave was finished, the obtained product was filtered to obtain an alkaline filter cake, and the alkaline filter cake was continuously rinsed with distilled water until the pH value of the filtrate flowing out of the rinse was 7, thereby obtaining a second neutral filter cake. The second neutral filter cake was then dried at a temperature of 70° C. for 2 hours to obtain 124 g of deproteinized shrimp shell powder.

(d) 500 mL of a 3M aqueous hydrochloric acid solution (composed of hydrochloric acid and water) was added to 124 g of the deproteinized shrimp shell powder at a rate of 0.6 mL/min, and then the mixture was placed in the above stirring apparatus and stirred at a temperature of 4.5° C. and a rotation speed of 8000 rpm/min for 4.5 hours to completely dissolve the deproteinized shrimp shell powder in the aqueous hydrochloric acid solution to obtain an acidic crude product. The acidity of the acidic crude product was then adjusted with distilled water to form a neutral crude product with a pH value of 7 and containing precipitates. The neutral crude product was centrifuged for 20 minutes using a centrifuge (source: Hunan Kaida Scientific Instrument Co., Ltd.; model: DL6M) at a speed of 15,000 rpm/min, and the precipitate was placed in a dialysis bag (source: Sinopharm Chemical Reagent Co., Ltd.; model: DM20 92420601; molecular weight cutoff: 8,000 Da to 14,000 Da) and dialyzed with deionized water for 3 days to obtain a dialyzed product. The dialyzed product was ultrasonically vibrated for 30 minutes at a power of 900 W using an ultrasonic vibration device (source: Changzhou Langyue Instrument Manufacturing Co., Ltd.; model: HH-2J), and then moved to a concentration device (source: Hubei Dot-Engraved Machinery Co., Ltd.; model: DK-DZ) and concentrated at a temperature of 55°C to obtain 118 g of chitosan nanopowder.

(e) 118 g of the chitosan nanopowder was dissolved in 500 g of acetic acid, and then 23.6 g of polyethylene glycol (source: Nantong Wenhui Chemical Co., Ltd.; average hydroxyl value: 102 mgKOH/g to 125 mgKOH/g; average relative molecular weight (Mr): 900 to 1100) was added, and then placed in the above stirring device and stirred at a temperature of 35° C. and a rotation speed of 900 rpm/min for 15 minutes to obtain a product to be purified containing modified chitosan nanopowder. The substance to be purified was placed in a defoaming device (source: Shenzhen Simaida Electronics Co., Ltd.; model: TWV-500T) at 25°C, and defoamed for 20 hours at a speed of 35 rpm/min to remove bubbles in the substance to be purified, thereby obtaining a defoamed mixture. The defoamed mixture was then placed in a dialysis bag (source: Zhejiang Boshi Medical Instrument Co., Ltd.; model: MD34; molecular weight cutoff: 10,000 Da) and dialyzed with distilled water for 24 hours to obtain a dialysate, and then a sodium hydroxide aqueous solution (composed of sodium hydroxide and water) with a concentration of 0.01 M was used to adjust the pH value of the dialysate to 12 to precipitate a solid containing the modified chitosan nanopowder. The solid was filtered through a funnel by vacuum filtration and rinsed with ethanol and vacuum filtration was continued to remove the ethanol, to obtain 139 g of the modified chitosan nanopowder.

(f) Providing a plant extract powder composed of aloe vera extract powder (source: Shaanxi Haisai Biotechnology Co., Ltd.), tea extract powder (source: Xi'an Hetaiyuan Biotechnology Co., Ltd.) and coral extract powder (source: Xi'an Anao Biotechnology Co., Ltd.), wherein the weight ratio of the aloe vera extract powder, the tea extract powder and the coral extract powder is 1:2:4, and the average particle size of the plant extract powder is 30 nm. 139 g of the modified chitin nanopowder, 28 g of the plant extract powder, 4.2 g of glycerol and 400 g of water are mixed in the above-mentioned ultrasonic oscillation equipment and ultrasonically oscillated for 25 minutes at a temperature of 40°C and a power of 400 W to obtain a homogeneous liquid with a clear appearance. After the homogenized liquid is cooled to room temperature, solids are precipitated to obtain a homogenized substance containing the solids. Then, the homogenized substance is filtered and the solids are taken out. The solids are dried at 55° C. for 3 hours to obtain 166 g of a functional component containing the modified chitosan nanopowder and the plant extract powder.

(g) Using the above stirring device, 300 parts by weight of the functional component and 700 parts by weight of viscose fiber spinning stock solution (source: Tangshan Sanyou Group Xingda Chemical Fiber Co., Ltd.; the viscose fiber spinning stock solution contains 9.5% to 9.8% of type A cellulose) are uniformly mixed at a temperature of 30°C and a rotation speed of 750 rpm/min to obtain a viscose fiber spinning mixed solution. The viscose fiber spinning mixed solution is then wet-spun to obtain a moisture-absorbing antibacterial functional fiber. In the wet spinning, a spinning device (source: Qingdao Nocon Environmental Protection Technology Co., Ltd.; model: HZ-SF-01) is used to spin the viscose fiber spinning mixture. The spinning device has a nozzle with 15,000 holes, each with a hole diameter of 0.06 mm, and a spinning speed of 30 m/min. The sprayed thin stream of the viscose fiber spinning mixture is coagulated into primary fibers in a coagulation bath composed of 60 g/L sulfuric acid, 50 g/L phosphoric acid and 35 g/L polyquaternary ammonium salt at a temperature of 45° C. The primary fibers are subjected to post-treatments including washing, desulfurization, bleaching, pickling, oiling and drying in sequence to obtain the moisture-absorbing and antibacterial functional fibers.

〈Implementation Example 2 to 9 〉

The conditions of each step in Examples 2 to 9 are shown in Tables 1 and 2. The difference between Examples 2 and 3 and Example 1 is that the mesh size of the shrimp shell powder used in step (a) is different. The difference between Examples 4 to 6 and Example 1 is that the amount ratio of the acidic treatment solution used in step (b) is different. The difference between Examples 7 to 9 and Example 1 is that the amount ratio of the alkaline treatment solution used in step (c) is different.

<Comparative example 1 to 7 〉

The conditions of each step in Comparative Examples 1 to 7 are shown in Table 3. The difference between Comparative Examples 1 and 2 and Example 1 is that the mesh size of the shrimp shell powder used in the step (a) is different. The difference between Comparative Example 3 and Example 1 is that the amount ratio of the acidic treatment solution used in the step (b) is different. The difference between Comparative Example 4 and Example 1 is that the amount ratio of the alkaline treatment solution used in the step (c) is different. The difference between Comparative Example 5 and Example 1 is that in the step (c), the alkaline treatment solution is reacted with the desalted shrimp shell powder for 10 minutes in an environment at a temperature of 45°C instead of in a microwave environment to remove the protein in the desalted shrimp shell powder. The difference between Comparative Example 6 and Example 1 is that in step (e), polyethylene glycol is not used, but the chitosan nanopowder is dissolved in acetic acid and then directly defoamed to obtain a defoamed mixture, the defoamed mixture is dialyzed to obtain a dialysate, and the pH value of the dialysate is adjusted to 10 to 13 to precipitate a solid containing modified chitosan nanopowder. The difference between Comparative Example 7 and Example 1 is that in step (f), plant extract powder is not used, but the modified chitosan nanopowder, glycerin and water are mixed and ultrasonically vibrated.

〈Evaluation Items〉

Chitosan purity of chitosan nanopowder (unit: %): The chitosan purity of chitosan nanopowders of Examples 1 to 9 and Comparative Examples 1 to 7 was measured using a high performance liquid chromatography (source: Shanghai Tianpu Analytical Instrument Co., Ltd.; model: LC8000) according to the detection method of "High Performance Liquid Chromatography Determination of Chitosan Purity". The results are recorded in Tables 1 to 3.

Average particle size of chitosan nanopowder (unit: nm): The average particle size of chitosan nanopowder of Examples 1 to 9 and Comparative Examples 1 to 7 was measured using a nanolaser particle size analyzer (source: Beijing Haixinrui Technology Co., Ltd.; model: HL2020-L). The results are recorded in Tables 1 to 3.

Consumption rate of modified chitin nanopowder (unit: %): Referring to CN110274969A "A method for detecting chitin in chitin polyester fiber", the sample of the moisture-absorbing antibacterial functional fiber of Example 1 is prepared to obtain a test solution. Then, the test solution is detected using the above-mentioned high-performance liquid chromatography to obtain the content of modified chitin nanopowder in the moisture-absorbing antibacterial functional fiber of Example 1. The consumption rate of the modified chitin nanopowder of Example 1 is calculated by the following formula. The consumption rates of the modified chitin nanopowder of Examples 2 to 9 and Comparative Examples 1 to 7 are obtained in the same manner, and the results are recorded in Tables 1 to 3. The formula is: Loss rate of modified chitosan nanopowder (%) = (m0-m1)/m0×100% Wherein, m0 = weight of modified chitosan nanopowder used in step (f) (g); and m1 = content of modified chitosan nanopowder in the moisture-absorbing antibacterial functional fiber (g).

The loss rate of plant extract powder (unit: %): Using the above-mentioned high performance liquid chromatography, according to the standard test methods of Q/532BLH12-2021 "Aloe fiber", Q/BTC0328-2019 "Tea fiber", and referring to "A brief discussion on the extraction and content detection of total flavonoids from Sarcandra glabra", the plant extract powder and the moisture-absorbing antibacterial functional fiber of Example 1 were measured to obtain the content of the active ingredient in the plant extract powder used in step (f) of Example 1, and the content of the active ingredient in the plant extract powder in the moisture-absorbing antibacterial functional fiber of Example 1. The loss rate of the plant extract powder of Example 1 was then calculated by the following formula. The loss rates of the plant extract powders of Examples 2 to 9 and Comparative Examples 1 to 7 were obtained in the same manner, and the results are recorded in Tables 1 to 3. The formula is: Loss rate of plant extract powder (%) = (a0-a1)/a0×100% Wherein, a0 = the content of the active ingredient in the plant extract powder used in step (f) (g); and a1 = the content of the active ingredient in the plant extract powder in the moisture-absorbing antibacterial functional fiber (g).

Loading rate of plant extract powder (unit: %): The loading rate of plant extract powder of the moisture-absorbing antibacterial functional fiber of Examples 1 to 9 and Comparative Examples 1 to 7 was calculated by the following formula, and the results are recorded in Tables 1 to 3. The formula is: Loading rate of plant extract powder (%) = a1/a0×100% Wherein, a0 = the content of active ingredient in the plant extract powder used in step (f) (g); and a1 = the content of active ingredient in the plant extract powder in the moisture-absorbing antibacterial functional fiber (g).

Dry breaking strength (unit: cN/dtex): According to the standard test method of GB/T 14463-2022 "Viscose staple fibers", the dry breaking strength of the moisture-absorbing and antibacterial functional fibers of Examples 1 to 9 and Comparative Examples 1 to 7 was measured, and the results are recorded in Tables 1 to 3.

Wet breaking strength (unit: cN/dtex): According to the standard test method of GB/T 14463-2022 "Viscose staple fibers", the wet breaking strength of the moisture-absorbing and antibacterial functional fibers of Examples 1 to 9 and Comparative Examples 1 to 7 was measured, and the results are recorded in Tables 1 to 3.

Antibacterial test: According to the standard test method of <D.8 Test method for antibacterial fabrics: oscillation method> in FZ/T 73023-2006 "Antibacterial knitwear", the moisture-absorbing antibacterial functional fiber of Example 1 was first washed 50 times and then tested for the antibacterial rate of Staphylococcus aureus, Escherichia coli and Candida albicans, and the antibacterial rate of the moisture-absorbing antibacterial functional fiber of Example 1 against Staphylococcus aureus, Escherichia coli and Candida albicans was obtained. The antibacterial rate of the moisture-absorbing antibacterial functional fiber of Examples 2 to 9 and Comparative Examples 1 to 7 was obtained in the same manner, and the results are recorded in Tables 1 to 3. The industry generally believes that when the moisture-absorbing antibacterial functional fiber has been washed 50 times, its antibacterial rate against Staphylococcus aureus is more than 80%, the antibacterial rate against Escherichia coli is more than 70%, and the antibacterial rate against Candida albicans is more than 60%, which means that the moisture-absorbing antibacterial functional fiber meets the AAA antibacterial level.

Moisture absorption and quick-drying test: According to the standard test method of GB/T 21655.1-2008 "Evaluation of moisture absorption and quick-drying of textiles Part 1: Single combination test method", the moisture absorption and antibacterial functional fibers of Examples 1 to 9 and Comparative Examples 1 to 7 were tested for five items before and after washing, including water absorption rate, drip diffusion time, wicking height, evaporation rate and moisture permeability. The first three items correspond to the evaluation of moisture absorption, and the last two items correspond to the evaluation of quick-drying. The results are recorded in Tables 1 to 3.

Appearance of the functional component: The appearance of the functional component of Example 1 was observed using a scanning electron microscope (source: MERLIN Compact, Germany; model: ZEISS EVO 18). The results are shown in FIG1 .

Table 1 Embodiment 1 2 3 4 5 (a) Shrimp Shell Powder Mesh 2000 1000 3000 2000 2000 (b) Shrimp Shell Powder Dosage(g) 500 Acidic treatment solution Element Formed by dissolving tartaric acid and citric acid in hydrochloric acid Dosage(mL) 8000 8000 8000 7500 9000 (c) Desalted Shrimp Shell Powder Dosage(g) 375 364 369 368 370 Alkaline treatment solution Element Formed by dissolving urea and sodium hydroxide in water Dosage(mL) 6000 5824 5904 5888 5920 microwave Temperature(℃) 45 Power(W) 220 Time(minutes) 10 (d) Chitosan Nanopowder Chitosan purity (%) 99 96 98 96 98 Average particle size (nm) 30 50 10 30 30 (e) Chitosan Nanopowder Dosage(g) 118 105 113 110 113 Acetic acid Dosage(g) 500 500 500 500 500 Polyethylene glycol Dosage(g) 23.6 twenty one 22.6 twenty two 22.6 (f) Plant extract powder Element Composed of Aloe vera extract powder, tea extract powder and Sarcandra glabra extract powder Dosage(g) 28 twenty four 27 25.8 26.2 (g) Moisture absorbing and antibacterial functional fiber Loss rate of modified chitosan nanopowder (%) 0.5 0.8 0.6 0.7 0.5 Loss rate of plant extract powder (%) 1.1 1.8 1.4 1.5 1.3 Plant extract powder loading rate (%) 99 96 97 98 99 Dry breaking strength (cN/dtex) 4.5 3.5 4.0 4.2 4.5 Wet breaking strength (cN/dtex) 3.4 2.5 3.0 3.1 3.2 Antibacterial rate against Staphylococcus aureus (%) 99 98 99 98 97 Antibacterial rate against E. coli (%) 99 97 98 98 96 Inhibition rate against Candida albicans (%) 97 95 96 97 95 Water absorption (%) 330 321 328 323 326 Drip diffusion time (sec) 2 3 2 3 2 Wicking height (mm) 180.5 174.2 178.6 175.6 179.3 Evaporation rate (g/h) 0.20 0.19 0.20 0.20 0.18 Moisture permeability [g/(m ² d)] 12521 12195 12326 12632 12747

Table 2 Embodiment 6 7 8 9 (a) Shrimp Shell Powder Mesh 2000 2000 2000 2000 (b) Shrimp Shell Powder Dosage(g) 500 Acidic treatment solution Element Formed by dissolving tartaric acid and citric acid in hydrochloric acid Dosage(mL) 10000 8000 8000 8000 (c) Desalted Shrimp Shell Powder Dosage(g) 372 362 373 374 Alkaline treatment solution Element Formed by dissolving urea and sodium hydroxide in water Dosage(mL) 5952 5792 6714 7480 microwave Temperature(℃) 45 Power(W) 220 Time(minutes) 10 (d) Chitosan Nanopowder Chitosan purity (%) 97 97 99 96 Average particle size (nm) 30 30 30 30 (e) Chitosan Nanopowder Dosage(g) 118 103 108 115 Acetic acid Dosage(g) 500 500 500 500 Polyethylene glycol Dosage(g) 23.6 20.6 21.6 23.0 (f) Plant extract powder Element Composed of Aloe vera extract powder, tea extract powder and Sarcandra glabra extract powder Dosage(g) 26.4 23.8 25.4 24.6 (g) Moisture absorbing and antibacterial functional fiber Loss rate of modified chitosan nanopowder (%) 0.8 0.7 0.5 0.5 Loss rate of plant extract powder (%) 1.9 1.7 1.4 1.1 Plant extract powder loading rate (%) 96 96 97 97 Dry breaking strength (cN/dtex) 4.1 3.9 4.0 4.3 Wet breaking strength (cN/dtex) 2.9 3.1 3.3 3.2 Antibacterial rate against Staphylococcus aureus (%) 98 97 99 97 Antibacterial rate against E. coli (%) 96 98 97 95 Inhibition rate against Candida albicans (%) 96 96 95 95 Water absorption (%) 308 319 321 317 Drip diffusion time (sec) 3 2 3 2 Wicking height (mm) 175.1 174.7 178.6 173.5 Evaporation rate (g/h) 0.20 0.18 0.20 0.20 Moisture permeability [g/(m ² d)] 11963 12793 12843 12416

Table 3 Comparative example 1 2 3 4 5 6 7 (a) Shrimp Shell Powder Mesh 500 4000 2000 2000 2000 2000 2000 (b) Shrimp Shell Powder Dosage(g) 500 Acidic treatment solution Element Formed by dissolving tartaric acid and citric acid in hydrochloric acid Dosage(mL) 8000 8000 5500 8000 8000 8000 8000 (c) Desalted Shrimp Shell Powder Dosage(g) 382 391 406 370 378 371 379 Alkaline treatment solution Element Formed by dissolving urea and sodium hydroxide in water Dosage(mL) 6112 6256 6496 3700 6048 5936 6064 microwave Temperature(℃) 45 No progress 45 Power(W) 220 220 Time(minutes) 10 10 (d) Chitosan Nanopowder Chitosan purity (%) 87 75 66 72 64 99 97 Average particle size (nm) 80 75 85 74 68 30 30 (e) Chitosan Nanopowder Dosage(g) 123 138 152 136 149 108 118 Acetic acid Dosage(g) 500 500 500 500 500 500 500 Polyethylene glycol Dosage(g) 24.6 27.6 30.4 27.2 29.8 No use 23.6 (f) Plant extract powder Element Composed of Aloe vera extract powder, tea extract powder and Sarcandra glabra extract powder No use Dosage(g) 28.4 30.4 35.4 31.8 32.4 18.6 (g) Moisture absorbing and antibacterial functional fiber Loss rate of modified chitosan nanopowder (%) 2.5 1.8 0.6 2.3 1.8 2.8 1.2 Loss rate of plant extract powder (%) 4.9 3.6 1.7 2.7 3.2 2.5 No measurement Plant extract powder loading rate (%) 75 66 94 70 74 88 No measurement Dry breaking strength (cN/dtex) 2.0 1.8 1.5 1.9 2.2 2.1 1.5 Wet breaking strength (cN/dtex) 1.4 1.2 1.3 1.1 0.9 0.7 1.2 Antibacterial rate against Staphylococcus aureus (%) 83 82 79 75 70 64 62 Antibacterial rate against E. coli (%) 80 75 77 70 66 60 55 Inhibition rate against Candida albicans (%) 72 70 66 68 60 55 50 Water absorption (%) 253 216 217 221 232 264 207 Drip diffusion time (sec) 5 8 7 6 7 5 6 Wicking height (mm) 128.2 117. 2 126.7 116.7 105.8 116.9 113.2 Evaporation rate (g/h) 0.50 0.80 0.60 0.90 1.20 1.50 1.30 Moisture permeability [g/(m ² d)] 932 914 904 957 895 814 848

Referring to Tables 1 to 3, compared with Comparative Examples 1 to 5, because the mesh size of the shrimp shell powder used in step (a) of Examples 1 to 9 is in the range of 1000 mesh to 3000 mesh, the amount of the acidic treatment solution used in step (b) is at least 15 mL (based on 1 g of the shrimp shell powder), and the alkaline treatment solution used in step (c) is at least 15 mL (based on 1 g of the shrimp shell powder). The amount of the treatment solution used is in the range of at least 15 mL (based on the amount of the desalted shrimp shell powder being 1 g), and the protein in the desalted shrimp shell powder is removed in a microwave environment, so that the chitosan nanopowders of Examples 1 to 9 have a higher purity (the chitosan purity ranges from 96% to 99%) and a smaller particle size (the average particle size ranges from 10 mm to 50 mm).

Compared with Comparative Examples 1 to 5, because the chitosan nanopowder of Examples 1 to 9 has the characteristics of high purity and small particle size, and is combined with the use of polyethylene glycol in step (e) and the use of plant extract powder in step (f), the prepared moisture-absorbing antibacterial functional fiber has a low loss rate of modified chitosan nanopowder (less than 0.8%), a low loss rate of plant extract powder (less than 1.9%) and a high loading rate of plant extract powder (more than 96%), thereby making the prepared moisture-absorbing antibacterial functional fiber have excellent breaking strength, antibacterial function and moisture-absorbing quick-drying function. In addition, the amount of the acidic treatment solution is controlled within a range of less than 20 mL (based on the amount of the shrimp shell powder being 1 g), and the amount of the alkaline treatment solution is controlled within a range of less than 20 mL (based on the amount of the desalted shrimp shell powder being 1 g), which is not likely to cause waste of amount and is not likely to cause a burden on the environment.

Compared with the moisture-absorbing and antibacterial functional fibers of Comparative Examples 6 and 7, because polyethylene glycol is used in step (e) and plant extract powder is used in step (f) in Examples 1 to 9, the moisture-absorbing and antibacterial functional fibers obtained have excellent breaking strength, antibacterial function and moisture-absorbing and quick-drying function.

As can be seen from the scanning electron microscope photograph of FIG. 1 , the appearance of the functional component of Example 1 has a plurality of pores, which indicates that in the functional component, the plant extract powders encapsulate but do not completely cover the surface of the modified chitosan nanopowder.

In summary, the method for preparing the moisture-absorbing antibacterial functional fiber of the present invention is that the mesh number range of the shrimp shell powder in the step (a) is designed to be 1000 mesh to 3000 mesh, and the inorganic salt in the shrimp shell powder is removed by using an acidic treatment liquid in an amount range of at least 15 mL (based on the amount of the shrimp shell powder being 1 g) in the step (b), and In the step (c), an alkaline treatment solution in an amount of at least 15 mL (based on 1 g of the desalted shrimp shell powder) is used to remove the protein in the desalted shrimp shell powder in a microwave environment, so that the chitosan purity of the chitosan nanopowder prepared in the step (d) is in the range of 96% to 99% and the average particle size is in the range of 10 nm to 50 nm. Since the chitosan nanopowder has the characteristics of high chitosan purity and small average particle size, the functional component can be stably and evenly dispersed in the spinning stock solution in the subsequent step (g) and is not easily consumed in the spinning process. As a result, the prepared moisture-absorbing and antibacterial functional fiber of the present invention not only has excellent breaking strength, but also has excellent antibacterial properties and moisture-absorbing and quick-drying properties. Furthermore, through the polyethylene glycol in step (e) and the plant extract powder in step (f), the functional component prepared can have good compatibility with the spinning stock solution, so the functional component will not cause problems such as blocking the nozzle during the spinning process, so that the moisture-absorbing and antibacterial functional fiber of the present invention has the advantages of good spinnability and is not easy to break. Therefore, the purpose of the present invention can be achieved.

However, the above is only an embodiment of the present invention and should not be used to limit the scope of implementation of the present invention. All simple equivalent changes and modifications made according to the scope of the patent application of the present invention and the content of the patent specification are still within the scope of the present patent.

Other features and effects of the present invention will be clearly presented in the embodiments with reference to the drawings, wherein: Figure 1 is a scanning electron microscope photograph illustrating the appearance of the functional components of Embodiment 1.

Claims (10)

A moisture-absorbing and antibacterial functional fiber, comprising: a polymer matrix; and a functional component, including a plant extract and a modified chitosan nanopowder; wherein the modified chitosan nanopowder is prepared by the following steps (a) to (e): (a). Shrimp shell blocks containing chitosan, an inorganic salt and a protein are crushed to obtain shrimp shell powder having a mesh size ranging from 1000 mesh to 3000 mesh and containing the chitosan, the inorganic salt and the protein; (b). Desalting the shrimp shell powder to remove the inorganic salt to obtain desalted shrimp shell powder containing the chitosan and the protein, wherein the desalting treatment includes using an acidic treatment liquid to remove the inorganic salt in the shrimp shell powder, and based on the amount of the shrimp shell powder being 1g, the amount of the acidic treatment liquid is at least 15mL; (c). The desalted shrimp shell powder is subjected to a deproteinization treatment to remove the protein, thereby obtaining a deproteinized shrimp shell powder containing the chitosan, wherein the deproteinization treatment includes removing the protein in the desalted shrimp shell powder using an alkaline treatment liquid in a microwave environment, and the amount of the alkaline treatment liquid is at least 15 mL based on the amount of the desalted shrimp shell powder being 1 g; (d). The deproteinized shrimp shell powder is subjected to a nano-treatment to obtain a chitosan nanopowder containing the chitosan, wherein the chitosan purity of the chitosan nanopowder is in the range of 96% to 99% and the average particle size is in the range of 10 nm to 50 nm; and (e) Modifying the chitosan nanopowder to obtain the modified chitosan nanopowder, wherein the modification includes dissolving the chitosan nanopowder in acetic acid and reacting with polyethylene glycol to obtain a product to be purified containing the modified chitosan nanopowder. The moisture-absorbing and antibacterial functional fiber as described in claim 1, wherein the functional component is prepared by the following step (f): (f). Mixing the modified chitosan nanopowder, the plant extract, glycerin and water and homogenizing them to obtain the functional component. The moisture-absorbing and antibacterial functional fiber as described in claim 1, wherein the acidic treatment solution of step (b) comprises an acidic substance and a solvent, the acidic substance is selected from hydrochloric acid, nitric acid, picric acid, tartaric acid, citric acid, apple acid, salicylic acid, caffeic acid or any combination thereof, and the solvent is selected from hydrochloric acid, nitric acid, water or any combination thereof. The moisture-absorbing and antibacterial functional fiber as described in claim 1, wherein the alkaline treatment solution of step (c) comprises an alkaline substance and water, and the alkaline substance is selected from urea, potassium hydroxide, sodium hydroxide, triethylamine, 4-lutidine or any combination thereof. The moisture-absorbing and antibacterial functional fiber as described in claim 1, wherein the weight ratio of the chitosan nanopowder to the polyethylene glycol in the step (e) is in the range of 1:0.1 to 0.3, the hydroxyl value of the polyethylene glycol is in the range of 102 mgKOH/g to 129 mgKOH/g and the average relative molecular weight is in the range of 900 to 1100. A method for preparing moisture-absorbing antibacterial functional fiber comprises the following steps: (a). Crushing shrimp shell blocks containing chitosan, inorganic salt and protein to obtain shrimp shell powder with a mesh size ranging from 1000 mesh to 3000 mesh and containing the chitosan, the inorganic salt and the protein; (b). Desalting the shrimp shell powder to remove the inorganic salt to obtain desalted shrimp shell powder containing the chitosan and the protein, wherein the desalting treatment includes using an acidic treatment liquid to remove the inorganic salt in the shrimp shell powder, and based on the amount of the shrimp shell powder being 1g, the amount of the acidic treatment liquid is at least 15mL; (c). The desalted shrimp shell powder is subjected to a deproteinization treatment to remove the protein, thereby obtaining a deproteinized shrimp shell powder containing the chitosan, wherein the deproteinization treatment includes removing the protein from the desalted shrimp shell powder using an alkaline treatment liquid in a microwave environment, and the amount of the alkaline treatment liquid is at least 15 mL based on the amount of the desalted shrimp shell powder being 1 g; (d). The deproteinized shrimp shell powder is subjected to a nano-treatment to obtain a chitosan nano powder containing the chitosan, wherein the chitosan purity of the chitosan nano powder is in the range of 96% to 99% and the average particle size is in the range of 10 nm to 50 nm; (e) Modifying the chitosan nanopowder to obtain the modified chitosan nanopowder, wherein the modification comprises dissolving the chitosan nanopowder in acetic acid and reacting with polyethylene glycol to obtain a purified product containing the modified chitosan nanopowder; (f) Mixing the modified chitosan nanopowder, plant extract, glycerin and water and homogenizing to obtain a functional component; and (g) Mixing the functional component with a spinning stock solution and performing a spinning process to obtain a moisture-absorbing and antibacterial functional fiber. A method for preparing moisture-absorbing and antibacterial functional fibers as described in claim 6, wherein the acidic treatment solution of step (b) comprises an acidic substance and a solvent, the acidic substance is selected from hydrochloric acid, nitric acid, picric acid, tartaric acid, citric acid, apple acid, salicylic acid, caffeic acid or any combination thereof, and the solvent is selected from hydrochloric acid, nitric acid, water or any combination thereof. The method for preparing the moisture-absorbing and antibacterial functional fiber as described in claim 6, wherein the alkaline treatment solution of step (c) comprises an alkaline substance and water, and the alkaline substance is selected from urea, potassium hydroxide, sodium hydroxide, triethylamine, 4-lutidine or any combination thereof. The method for preparing the moisture-absorbing and antibacterial functional fiber as described in claim 6, wherein the modification treatment of the step (e) further includes defoaming the substance to be purified to obtain a defoamed mixture, dialyzing the defoamed mixture to obtain a dialysate, and adjusting the pH value of the dialysate to 10 to 13 to precipitate a solid containing the modified chitosan nanopowder. A method for preparing moisture-absorbing and antibacterial functional fibers as described in claim 6, wherein the weight ratio of the chitosan nanopowder to the polyethylene glycol in step (e) is in the range of 1:0.1 to 0.3, the hydroxyl value of the polyethylene glycol is in the range of 102 mgKOH/g to 129 mgKOH/g and the average relative molecular weight is in the range of 900 to 1100.