A skin-friendly blended denim and a method for manufacturing the same

Abstract

This invention relates to the field of textile finishing technology and discloses a skin-friendly blended denim fabric and its preparation method, comprising the following steps: mixing blended denim fabric, sodium hydroxide solution, and sodium bicarbonate solution evenly, heat-treating, removing, washing, and drying to obtain pre-treated blended denim fabric; mixing polyacrylate emulsion, polyether-modified silicone oil, skin-friendly modifier, and deionized water, stirring evenly to obtain a skin-friendly finishing agent; immersing the pre-treated blended denim fabric in the skin-friendly finishing agent, treating, removing, and baking to obtain skin-friendly blended denim fabric. Testing and determination show that the skin-friendly blended denim fabric can quickly absorb excess moisture and keep dry, exhibiting high moisture-wicking, antibacterial, and soft properties, demonstrating the high skin-friendly properties of blended denim fabric.

Description

Technical Field

[0001] This invention relates to the field of textile finishing technology, specifically to a skin-friendly blended denim fabric and its preparation method. Background Technology

[0002] Denim is a relatively thick, yarn-dyed twill cotton fabric. The warp yarns are dark, usually indigo, while the weft yarns are light, usually light gray or bleached off-white. Denim is also known as indigo workwear. Denim is a popular fabric because it is both durable and fashionable, adaptable, and comfortable. It can meet people's needs for both everyday wear and fashion. Traditional blended denim is mainly made by weaving indigo-dyed pure cotton warp yarns and natural-colored weft yarns in a right-hand twill weave with a 3-up-1-down pattern, which can reflect a deep blue color with a strong retro feel.

[0003] With the advancement of textile technology, the functional requirements for denim fabrics are no longer limited to traditional wear resistance, easy care, and fashionable appearance. Instead, greater emphasis is placed on skin-friendly comfort and softness. Blended denim fabrics, often made from cotton and polyester blends, have poor moisture absorption and wicking properties, leading to stuffiness and affecting skin-friendly performance. Furthermore, traditional hydrophilic finishing processes make the surface of blended denim fabric hydrophilic, causing sweat to remain on the surface. When blended denim comes into direct contact with the skin, the sweat creates a sticky feeling, affecting skin-friendly performance. In addition, sweat accumulates in the inner layers of blended denim fabric and cannot diffuse and evaporate quickly, resulting in stuffiness and discomfort against the skin, further impacting skin-friendly performance.

[0004] When cellulose nanofibers, porous silica, and nanofiber palygorskite are mixed with skin-friendly finishing agents, the blended denim fabric can be treated to improve its water absorption and wicking properties. However, cellulose nanofibers, porous silica, and nanofiber palygorskite have large specific surface areas and high surface energy, making them prone to agglomeration and poor dispersion stability in skin-friendly finishing agents. Furthermore, simple physical blending makes it difficult to achieve synergistic improvement in water absorption and wicking properties among the components. Summary of the Invention

[0005] This invention provides a skin-friendly blended denim fabric and its preparation method, which solves the problem of poor moisture absorption and wicking properties of blended denim fabric, affecting its skin-friendly effect.

[0006] The technical solution of the present invention: A method for preparing a skin-friendly blended denim fabric includes the following steps: S1. Mix the blended denim fabric, sodium hydroxide solution and sodium bicarbonate solution evenly, heat treat, remove, wash and dry to obtain pretreated blended denim fabric. S2. Mix polyacrylate emulsion, polyether-modified silicone oil, skin-friendly modifier and deionized water, stir evenly to obtain skin-friendly finishing agent; S3. Immerse the pretreated blended denim fabric in a skin-friendly finishing agent and treat it at 50-60℃ for 30-40 minutes. Take it out and bake it at 80-100℃ for 3-5 minutes to obtain a skin-friendly blended denim fabric. The skin-friendly modifier is obtained by surface treatment of composite nanofibers with aminosilane, followed by mixing and reaction with sodium carboxymethyl cellulose and carboxymethyl chitosan. The composite nanofibers are obtained by synthesizing a porous silica layer on the surface of cellulose nanofibers, and then reacting it with tannic acid and palygorskite nanofibers.

[0007] Furthermore, in step S1, the heat treatment temperature is 70-80℃ and the heat treatment time is 15-20min.

[0008] Further, in step S1, the mass ratio of the blended denim fabric, sodium hydroxide solution, and sodium bicarbonate solution is 1:(8-10):(18-22).

[0009] Further, in step S1, the concentration of the sodium hydroxide solution is 5-10 g / L, and the concentration of the sodium bicarbonate solution is 10-15 g / L.

[0010] Furthermore, in step S1, the sodium hydroxide solution and sodium bicarbonate solution form a buffer alkali solution, which, in conjunction with heat treatment, can remove sizing agents, floating dyes, and oil stains from the surface of the blended denim fabric. This facilitates the application of skin-friendly finishing agents without causing damage to the fiber matrix, a decrease in strength, or structural fading.

[0011] Further, in step S2, the mass ratio of the polyacrylate emulsion, polyether-modified silicone oil, skin-friendly modifier, and deionized water is (0.2-0.4):(0.1-0.3):(1-2):(80-100).

[0012] Furthermore, in step S2, the hydrophilic polyacrylate emulsion acts as an adhesive to form a continuous and dense base film on the surface of the blended denim fabric, exhibiting strong adhesion and water resistance; the polyether-modified silicone oil, as a hydrophilic silicone softener, retains the soft feel of silicone while the polyether segments provide hydrophilicity and moisture permeability; the skin-friendly modifier penetrates the interface between the two phases, preventing the composite film from delaminating, breaking down, separating oil, or precipitating.

[0013] Further, in step S3, the bath ratio of the pretreated blended denim fabric to the skin-friendly finishing agent is 1:(30-50).

[0014] Furthermore, the skin-friendly modifier is specifically prepared by the following steps: A1. Cellulose nanofibers were mixed with deionized water and ethanol, ultrasonically dispersed, and then ammonia was added to adjust the pH. Tetraethoxysilane was then added, and after stirring and reaction, the mixture was filtered, washed, and dried to obtain modified cellulose nanofibers. A2. Mix the modified cellulose nanofibers, tannic acid and deionized water evenly, stir, add the nanofiber palygorskite, continue stirring, take out and dry to obtain composite cellulose nanofibers. A3. Mix the composite cellulose nanofibers, ethanol and deionized water evenly, add silane coupling agent, stir and react, cool to room temperature, filter, wash and dry to obtain functionalized composite cellulose nanofibers. A4. Add sodium carboxymethyl cellulose and carboxymethyl chitosan to deionized water, stir evenly, add citric acid and functionalized composite cellulose nanofibers, stir evenly, add hydrochloric acid to adjust pH, stir to react, let stand until a hydrogel is formed, freeze-dry the hydrogel to obtain the skin-friendly modifier.

[0015] Furthermore, during the A1 reaction described above, under alkaline conditions, the hydroxyl groups generated by the hydrolysis of tetraethoxysilane can chemically bond with the hydroxyl groups on the surface of cellulose nanofibers. As the hydrolysis and condensation reaction proceeds, the silica layer generated by the hydrolysis of tetraethoxysilane is coated onto the surface of the cellulose nanofibers, thereby forming a porous silica layer on the surface of the cellulose nanofibers and obtaining modified cellulose nanofibers.

[0016] Furthermore, in the A2 reaction process described above, tannic acid contains a large number of phenolic hydroxyl groups, which have high adhesion properties and can adhere to the surface of modified cellulose nanofibers through chemical bonds. A large number of phenolic hydroxyl groups are introduced into the surface of modified cellulose nanofibers. The phenolic hydroxyl groups contained therein can serve as binding sites for palygorskite nanofibers, so that palygorskite nanofibers are uniformly coated on the surface of modified cellulose nanofibers by tannic acid, thus obtaining composite nanofibers.

[0017] Furthermore, during the A3 reaction process described above, the silanol groups generated by the hydrolysis of aminosilane can chemically bond with the hydroxyl groups on the surface of the composite nanofibers, thereby grafting aminosilane onto the surface of the composite nanofibers and obtaining aminated composite nanofibers.

[0018] Furthermore, in the A3 reaction process described above, carboxymethyl cellulose and carboxymethyl chitosan are used as the aerogel framework, and citric acid is used as a crosslinking agent, so that carboxymethyl cellulose and carboxymethyl chitosan form a crosslinked aerogel. The amino groups contained in the aminated composite nanofibers can also participate in the crosslinking reaction, so that the aminated composite nanofibers are embedded in the aerogel structure to obtain a composite aerogel, which serves as a skin-friendly modifier.

[0019] Further, in step A1, the mass ratio of the cellulose nanofibers, deionized water, ethanol and tetraethoxysilane is (1-1.2):(30-40):(90-100):(0.8-1).

[0020] Further, in step A2, the mass ratio of the modified cellulose nanofibers, tannic acid, deionized water and nanofiber palygorskite is (1.2-1.5):(0.1-0.2):(80-100):(1-1.2).

[0021] Further, in step A3, the mass ratio of the composite cellulose nanofibers, ethanol, deionized water and silane coupling agent is (1.2-1.4):(90-100):(30-40):(0.1-0.3).

[0022] In step A4, the mass ratio of sodium carboxymethyl cellulose, carboxymethyl chitosan, deionized water, citric acid, and functionalized composite cellulose nanofibers is (1-1.2):(1.2-1.4):(120-150):(0.2-0.4):(0.5-0.8).

[0023] The present invention has the following beneficial effects: (1) In the technical solution of the present invention, a porous silica layer is formed on the surface of cellulose nanofibers. On the one hand, the formed porous silica layer has a high adsorption capacity, which can be used to adsorb and release sweat, so that denim has a good absorption and sweat-wicking function. Moreover, cellulose nanofibers have a high specific surface area and aspect ratio, which can load more porous silica, enhance the absorption and sweat-wicking performance, and thus improve the skin-friendly performance of blended denim, avoiding poor sweat wicking, slow drying after wetting, easy sticking to the skin and body, and heavy wearing. On the other hand, cellulose nanofibers have a high aspect ratio and the surface contains rich oxygen-containing functional groups. Sweat can diffuse on the surface of cellulose nanofibers, thereby dispersing the sweat adsorbed in the porous silica into the interior of the denim and spreading in all directions along the warp and weft yarns to complete the sweat wicking, avoiding the concentration of sweat, the limited sweat wicking effect of denim, the sticky feeling on the skin surface, and the impact on skin-friendly performance.

[0024] (2) In the technical solution of the present invention, the nanofiber palygorskite is uniformly coated on the surface of the modified cellulose nanofiber to form composite nanofibers by tannic acid. On the one hand, the nanofiber palygorskite has a layered chain molecular structure, and the crystals are needle-shaped and fibrous. It has unique nanopores and excellent water absorption properties. The nanofiber palygorskite coated on the surface of the modified cellulose nanofiber forms a multi-layered composite nanofiber with a high adsorption capacity. It can absorb more sweat and diffuse the sweat into the denim through the nanofiber, thereby improving the skin-friendly properties of the denim. On the other hand, the nanofiber palygorskite is fixed on the surface of the cellulose nanofiber, avoiding the agglomeration of the nanofiber palygorskite. It is difficult to disperse evenly when directly added to the finishing agent, which affects the water absorption and perspiration performance.

[0025] (3) In the technical solution of the present invention, aminosilane is grafted onto the surface of composite nanofibers to provide active functional groups on the surface of composite nanofibers, which is beneficial to embed composite nanofibers into aerogel structure, so that composite nanofibers are uniformly dispersed on the surface of denim fabric and improve the skin-friendly properties of denim fabric. Using carboxymethyl cellulose and chitosan as the aerogel framework, aminated composite nanofibers are embedded in the aerogel structure. On the one hand, the aerogel surface formed by carboxymethyl cellulose and chitosan has high activity and can be uniformly dispersed in the skin-friendly finishing agent, allowing the skin-friendly modifier to be uniformly attached to the denim surface, improving the denim's absorbency and sweat-wicking performance. Furthermore, the aerogel has a large pore structure and hydrophilicity, which can adsorb sweat into the aerogel pores, and then diffuse the sweat into the denim through the composite nanofiber network inside the aerogel, improving the denim's skin-friendly properties. On the other hand, the formation of a hydrophilic aerogel layer on the denim surface can absorb sweat into the three-dimensional network structure of the aerogel for storage and conduction. This solves the problem of traditional hydrophilic finishing making the denim surface hydrophilic, causing sweat to remain on the denim surface and directly contacting the skin, resulting in a sticky feeling and affecting skin-friendly performance. In addition, the organic aerogel prepared with carboxymethyl cellulose and chitosan has good antibacterial activity and softness, improving the antibacterial and soft properties of the denim.

[0026] (4) In the technical solution of the present invention, the porous silica layer is attached to the surface of cellulose nanofiber as the inner layer of sweat absorption, the nanofiber palygorskite is the middle layer, and the carboxymethyl cellulose-chitosan aerogel is the outer layer. It has a layered composite structure, has a high sweat absorption capacity, avoids sweat concentration, and the denim fabric has limited sweat wicking effect, forming a sticky feeling on the skin surface, affecting the skin-friendly performance. It also breaks through the technical bottleneck that cellulose nanofiber, porous silica, and nanofiber palygorskite have large specific surface areas and high surface energy, are easy to agglomerate in skin-friendly finishing agents, have poor dispersion stability, and are difficult to achieve the synergistic improvement of water absorption and sweat wicking performance of each component by simple physical blending.

[0027] (5) In the technical solution of the present invention, the blended denim fabric is treated with alkali to form a pretreated blended denim fabric, and polyacrylate emulsion, polyether modified silicone oil, skin-friendly modifier and deionized water are mixed to form a skin-friendly finishing agent. The skin-friendly finishing agent is applied to the surface of the pretreated blended denim fabric to prepare a skin-friendly blended denim fabric. After testing and determination, the skin-friendly blended denim fabric can quickly absorb excess moisture and keep dry, and has high moisture absorption and perspiration wicking performance, antibacterial performance and softness performance, so as to reflect the high skin-friendly performance of the blended denim fabric. Detailed Implementation

[0028] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0029] The raw materials used in the embodiments of this invention are shown below, and all reagents used are analytical grade.

[0030] The blended denim is a cotton-polyester blended denim, with 65% cotton and 35% polyester. The warp yarn count is 40S, the weft yarn count is 40S, the warp density is 133 ends / inch, the weft density is 76 ends / inch, the warp yarn has 1000 twists / m, and the weft yarn has 900 twists / m.

[0031] Nanofiber palygorskite is prepared by the following steps: Papyrite ore is beneficiated, dried at 80℃, peeled into flakes, and then crushed in an SF-120 pulverizer and passed through a 100-mesh sieve to obtain paddyrite ore powder. The paddyrite ore powder is then pulped and centrifuged to collect nanofiber paddyrite. During the pulping process, the solid-liquid ratio is 1:20, the pulping shear rate is 2000 r / min, and the pulping shearing time is 2 h; the centrifugation rate is 12000 r / min, and the centrifugation time is 20 min.

[0032] The polyacrylate emulsion is of industrial grade, with an active ingredient content of 99% and a density of 1.2 g / mL at 25℃. It was purchased from Shandong Guohua Chemical Co., Ltd.

[0033] The polyether-modified silicone oil, product number P875564, was purchased from Shanghai Maclean Biochemical Technology Co., Ltd.

[0034] Cellulose nanofibers are carboxylated cellulose nanofibers (CNF), grade CNF-CD1, with diameters of 4-20 nm and lengths of 1-3 nm. m, purchased from Guilin Qihong Technology Co., Ltd.

[0035] The silane coupling agent is KH550 (γ-aminopropyltriethoxysilane).

[0036] Sodium carboxymethyl cellulose, USP grade, viscosity 2000 mPa·s; and carboxymethyl chitosan, BR grade, were purchased from Shanghai Maclean Biochemical Technology Co., Ltd.

[0037] Example 1 A method for preparing a skin-friendly blended denim fabric includes the following steps: S1. Mix the blended denim fabric, sodium hydroxide solution, and sodium bicarbonate solution evenly, perform heat treatment, remove, wash with water, and dry at 70℃ for 15 minutes to obtain the pretreated blended denim fabric; the heat treatment temperature is 70℃ and the heat treatment time is 15 minutes; the mass ratio of blended denim fabric, sodium hydroxide solution with a concentration of 5 g / L, and sodium bicarbonate solution with a concentration of 10 g / L is 1:8:18. S2. Mix polyacrylate emulsion, polyether-modified silicone oil, skin-friendly modifier and deionized water, and stir evenly to obtain skin-friendly finishing agent; the mass ratio of polyacrylate emulsion, polyether-modified silicone oil, skin-friendly modifier and deionized water is 0.2:0.1:1:80. S3. Immerse the pretreated blended denim fabric in a skin-friendly finishing agent, treat it at 50℃ for 30 minutes, remove it, and bake it at 80℃ for 3 minutes to obtain a skin-friendly blended denim fabric; the bath ratio of the pretreated blended denim fabric to the skin-friendly finishing agent is 1:30.

[0038] The skin-friendly modifier is prepared by the following steps: A1. Cellulose nanofibers were mixed with deionized water and ethanol, ultrasonically dispersed at 40 kHz for 20 min, and the pH was adjusted to 9 by adding 30% ammonia water. Tetraethoxysilane was added, and the mixture was stirred at 300 r / min and 40 °C for 8 h. After filtration, the mixture was washed three times with deionized water and dried in an oven at 60 °C for 24 h to obtain modified cellulose nanofibers. The mass ratio of cellulose nanofibers, deionized water, ethanol and tetraethoxysilane was 1:30:90:0.8. A2. Mix modified cellulose nanofibers, tannic acid, and deionized water evenly, stir at 70℃ for 30 min, add nanofiber palygorskite, continue stirring for 30 min, remove, and dry in an oven at 70℃ for 1 h to obtain composite cellulose nanofibers; the mass ratio of modified cellulose nanofibers, tannic acid, deionized water, and nanofiber palygorskite is 1.2:0.1:80:1; A3. The composite cellulose nanofibers, ethanol, and deionized water were mixed evenly, KH550 was added, and the mixture was stirred at 70°C for 3 hours. After cooling to room temperature, the mixture was filtered, washed three times with ethanol, and three times with deionized water. The mixture was then dried in an oven at 70°C for 10 minutes to obtain functionalized composite cellulose nanofibers. The mass ratio of composite cellulose nanofibers, ethanol, deionized water, and KH550 was 1.2:90:30:0.1. A4. Sodium carboxymethyl cellulose and carboxymethyl chitosan were added to deionized water and stirred at 500 r / min and 25℃ for 40 min. Citric acid and functionalized composite cellulose nanofibers were added and stirred evenly. Hydrochloric acid with a concentration of 0.1 mol / L was added to adjust the pH to 3.5. The mixture was stirred at 60℃ for 2 h and allowed to stand until a hydrogel was formed. The hydrogel was then freeze-dried at 400 Pa vacuum and -20℃ for 24 h to obtain a skin-friendly modifier. The mass ratio of sodium carboxymethyl cellulose, carboxymethyl chitosan, deionized water, citric acid and functionalized composite cellulose nanofibers was 1:1.2:120:0.2:0.5.

[0039] Example 2 A method for preparing a skin-friendly blended denim fabric includes the following steps: S1. Mix the blended denim fabric, sodium hydroxide solution, and sodium bicarbonate solution evenly, perform heat treatment, remove, wash with water, and dry at 70℃ for 15 minutes to obtain the pretreated blended denim fabric; the heat treatment temperature is 75℃ and the heat treatment time is 18 minutes; the mass ratio of blended denim fabric, sodium hydroxide solution with a concentration of 8 g / L, and sodium bicarbonate solution with a concentration of 13 g / L is 1:9:20. S2. Mix polyacrylate emulsion, polyether-modified silicone oil, skin-friendly modifier and deionized water, and stir evenly to obtain skin-friendly finishing agent; the mass ratio of polyacrylate emulsion, polyether-modified silicone oil, skin-friendly modifier and deionized water is 0.3:0.2:1.5:90; S3. Immerse the pretreated blended denim fabric in a skin-friendly finishing agent and treat it at 55℃ for 35 minutes. Remove it and bake it at 90℃ for 4 minutes to obtain a skin-friendly blended denim fabric. The bath ratio of the pretreated blended denim fabric to the skin-friendly finishing agent is 1:40.

[0040] The skin-friendly modifier is prepared by the following steps: A1. Cellulose nanofibers were mixed with deionized water and ethanol, and ultrasonically dispersed at 40 kHz for 20 min. Ammonia water with a mass fraction of 30% was added to adjust the pH to 9. Tetraethoxysilane was added, and the mixture was stirred at 300 r / min and 40 °C for 8 h. After filtration, the mixture was washed three times with deionized water and dried in an oven at 60 °C for 24 h to obtain modified cellulose nanofibers. The mass ratio of cellulose nanofibers, deionized water, ethanol, and tetraethoxysilane was 1.1:35:95:0.9. A2. Mix modified cellulose nanofibers, tannic acid, and deionized water evenly, stir at 70℃ for 30 min, add nanofiber palygorskite, continue stirring for 30 min, remove, and dry in an oven at 70℃ for 1 h to obtain composite cellulose nanofibers; the mass ratio of modified cellulose nanofibers, tannic acid, deionized water, and nanofiber palygorskite is 1.3:0.15:90:1.1; A3. The composite cellulose nanofibers, ethanol, and deionized water were mixed evenly, KH550 was added, and the mixture was stirred at 70°C for 3 hours. After cooling to room temperature, the mixture was filtered, washed three times with ethanol, and three times with deionized water. The mixture was then dried in an oven at 70°C for 10 minutes to obtain functionalized composite cellulose nanofibers. The mass ratio of composite cellulose nanofibers, ethanol, deionized water, and KH550 was 1.3:95:35:0.2. A4. Sodium carboxymethyl cellulose and carboxymethyl chitosan were added to deionized water and stirred at 500 r / min and 25℃ for 40 min. Citric acid and functionalized composite cellulose nanofibers were added and stirred evenly. Hydrochloric acid with a concentration of 0.1 mol / L was added to adjust the pH to 3.5. The mixture was stirred at 60℃ for 2 h and allowed to stand until a hydrogel was formed. The hydrogel was then freeze-dried at 400 Pa vacuum and -20℃ for 24 h to obtain a skin-friendly modifier. The mass ratio of sodium carboxymethyl cellulose, carboxymethyl chitosan, deionized water, citric acid and functionalized composite cellulose nanofibers was 1.1:1.3:130:0.3:0.7.

[0041] Example 3 A method for preparing a skin-friendly blended denim fabric includes the following steps: S1. Mix the blended denim fabric, sodium hydroxide solution, and sodium bicarbonate solution evenly, perform heat treatment, remove, wash with water, and dry at 70℃ for 15 minutes to obtain the pretreated blended denim fabric; the heat treatment temperature is 80℃ and the heat treatment time is 20 minutes; the mass ratio of blended denim fabric, 10 g / L sodium hydroxide solution, and 15 g / L sodium bicarbonate solution is 1:10:22. S2. Mix polyacrylate emulsion, polyether-modified silicone oil, skin-friendly modifier and deionized water, and stir evenly to obtain skin-friendly finishing agent; the mass ratio of polyacrylate emulsion, polyether-modified silicone oil, skin-friendly modifier and deionized water is 0.4:0.3:2:100. S3. Immerse the pretreated blended denim fabric in a skin-friendly finishing agent and treat it at 60℃ for 40 minutes. Remove it and bake it at 100℃ for 5 minutes to obtain a skin-friendly blended denim fabric. The bath ratio of the pretreated blended denim fabric to the skin-friendly finishing agent is 1:50.

[0042] The skin-friendly modifier is prepared by the following steps: A1. Cellulose nanofibers were mixed with deionized water and ethanol, ultrasonically dispersed at 40 kHz for 20 min, and the pH was adjusted to 9 by adding 30% ammonia water. Tetraethoxysilane was added, and the mixture was stirred at 300 r / min and 40 °C for 8 h. After filtration, the mixture was washed three times with deionized water and dried in an oven at 60 °C for 24 h to obtain modified cellulose nanofibers. The mass ratio of cellulose nanofibers, deionized water, ethanol and tetraethoxysilane was 1.2:40:100:1. A2. Mix modified cellulose nanofibers, tannic acid, and deionized water evenly, stir at 70℃ for 30 min, add palygorskite nanofibers, continue stirring for 30 min, remove, and dry in an oven at 70℃ for 1 h to obtain composite cellulose nanofibers; the mass ratio of modified cellulose nanofibers, tannic acid, deionized water, and palygorskite nanofibers is 1.5:0.2:100:1.2; A3. The composite cellulose nanofibers, ethanol, and deionized water were mixed evenly, KH550 was added, and the mixture was stirred at 70°C for 3 hours. After cooling to room temperature, the mixture was filtered, washed three times with ethanol, and three times with deionized water. The mixture was then dried in an oven at 70°C for 10 minutes to obtain functionalized composite cellulose nanofibers. The mass ratio of composite cellulose nanofibers, ethanol, deionized water, and KH550 was 1.4:100:40:0.3. A4. Sodium carboxymethyl cellulose and carboxymethyl chitosan were added to deionized water and stirred at 500 r / min and 25℃ for 40 min. Citric acid and functionalized composite cellulose nanofibers were added and stirred evenly. Hydrochloric acid with a concentration of 0.1 mol / L was added to adjust the pH to 3.5. The mixture was stirred at 60℃ for 2 h and allowed to stand until a hydrogel was formed. The hydrogel was then freeze-dried at 400 Pa vacuum and -20℃ for 24 h to obtain a skin-friendly modifier. The mass ratio of sodium carboxymethyl cellulose, carboxymethyl chitosan, deionized water, citric acid and functionalized composite cellulose nanofibers was 1.2:1.4:150:0.4:0.8.

[0043] Comparative Example 1 The only difference between this comparative example and Example 3 is the preparation of the skin-friendly modifier, as detailed below: The skin-friendly modifier is prepared by the following steps: A1. Mix cellulose nanofibers, tannic acid, and deionized water evenly, stir at 70℃ for 30 min, add palygorskite nanofibers, continue stirring for 30 min, remove, and dry in an oven at 70℃ for 1 h to obtain composite cellulose nanofibers; the mass ratio of cellulose nanofibers, tannic acid, deionized water, and palygorskite nanofibers is 1.5:0.2:100:1.2; A2. The composite cellulose nanofibers, ethanol, and deionized water were mixed evenly, KH550 was added, and the mixture was stirred at 70°C for 3 hours. After cooling to room temperature, the mixture was filtered, washed three times with ethanol, and three times with deionized water. The mixture was then dried in an oven at 70°C for 10 minutes to obtain functionalized composite cellulose nanofibers. The mass ratio of composite cellulose nanofibers, ethanol, deionized water, and KH550 was 1.4:100:40:0.3. A3. Sodium carboxymethyl cellulose and carboxymethyl chitosan were added to deionized water and stirred at 500 r / min and 25℃ for 40 min. Citric acid and functionalized composite cellulose nanofibers were added and stirred evenly. Hydrochloric acid with a concentration of 0.1 mol / L was added to adjust the pH to 3.5. The mixture was stirred at 60℃ for 2 h and allowed to stand until a hydrogel was formed. The hydrogel was freeze-dried at -20℃ for 24 h to obtain a skin-friendly modifier. The mass ratio of sodium carboxymethyl cellulose, carboxymethyl chitosan, deionized water, citric acid and functionalized composite cellulose nanofibers was 1.2:1.4:150:0.4:0.8.

[0044] Comparative Example 2 The only difference between this comparative example and Example 3 is the preparation of the skin-friendly modifier, as detailed below: The skin-friendly modifier is prepared by the following steps: A1. Cellulose nanofibers were mixed with deionized water and ethanol, ultrasonically dispersed at 40 kHz for 20 min, and the pH was adjusted to 9 by adding 30% ammonia water. Tetraethoxysilane was added, and the mixture was stirred at 300 r / min and 40 °C for 8 h. After filtration, the mixture was washed three times with deionized water and dried in an oven at 60 °C for 24 h to obtain modified cellulose nanofibers. The mass ratio of cellulose nanofibers, deionized water, ethanol and tetraethoxysilane was 1.2:40:100:1. A2. Modified cellulose nanofibers, ethanol, and deionized water were mixed evenly, KH550 was added, and the mixture was stirred at 70℃ for 3 hours. After cooling to room temperature, the mixture was filtered, washed three times with ethanol, and three times with deionized water. The mixture was then dried in a 70℃ oven for 10 minutes to obtain functionalized modified cellulose nanofibers. The mass ratio of modified cellulose nanofibers, ethanol, deionized water, and KH550 was 1.4:100:40:0.3. A3. Sodium carboxymethyl cellulose and carboxymethyl chitosan were added to deionized water and stirred at 500 r / min and 25℃ for 40 min. Citric acid and functionalized modified cellulose nanofibers were added and stirred evenly. Hydrochloric acid with a concentration of 0.1 mol / L was added to adjust the pH to 3.5. The mixture was stirred at 60℃ for 2 h and allowed to stand until a hydrogel was formed. The hydrogel was then freeze-dried at 400 Pa vacuum and -20℃ for 24 h to obtain a skin-friendly modifier. The mass ratio of sodium carboxymethyl cellulose, carboxymethyl chitosan, deionized water, citric acid and functionalized modified cellulose nanofibers was 1.2:1.4:150:0.4:0.8.

[0045] Comparative Example 3 The only difference between this comparative example and Example 3 is the preparation of the skin-friendly modifier, as detailed below: The skin-friendly modifier is prepared by the following steps: A1. Cellulose nanofibers were mixed with deionized water and ethanol, ultrasonically dispersed at 40 kHz for 20 min, and the pH was adjusted to 9 by adding 30% ammonia water. Tetraethoxysilane was added, and the mixture was stirred at 300 r / min and 40 °C for 8 h. After filtration, the mixture was washed three times with deionized water and dried in an oven at 60 °C for 24 h to obtain modified cellulose nanofibers. The mass ratio of cellulose nanofibers, deionized water, ethanol and tetraethoxysilane was 1.2:40:100:1. A2. Mix modified cellulose nanofibers, tannic acid, and deionized water evenly, stir at 70℃ for 30 min, add palygorskite nanofibers, continue stirring for 30 min, remove, and dry in an oven at 70℃ for 1 h to obtain composite cellulose nanofibers; the mass ratio of modified cellulose nanofibers, tannic acid, deionized water, and palygorskite nanofibers is 1.5:0.2:100:1.2; A3. Sodium carboxymethyl cellulose and carboxymethyl chitosan were added to deionized water and stirred at 500 r / min and 25℃ for 40 min. Citric acid and composite cellulose nanofibers were added and stirred evenly. Hydrochloric acid with a concentration of 0.1 mol / L was added to adjust the pH to 3.5. The mixture was stirred at 60℃ for 2 h and allowed to stand until a hydrogel was formed. The hydrogel was then freeze-dried at 400 Pa vacuum and -20℃ for 24 h to obtain a skin-friendly modifier. The mass ratio of sodium carboxymethyl cellulose, carboxymethyl chitosan, deionized water, citric acid and composite cellulose nanofibers was 1.2:1.4:150:0.4:0.8.

[0046] Comparative Example 4 The only difference between this comparative example and Example 3 is the preparation of the skin-friendly modifier, as detailed below: The skin-friendly modifier is prepared by the following steps: A1. Cellulose nanofibers were mixed with deionized water and ethanol, ultrasonically dispersed at 40 kHz for 20 min, and the pH was adjusted to 9 by adding 30% ammonia water. Tetraethoxysilane was added, and the mixture was stirred at 300 r / min and 40 °C for 8 h. After filtration, the mixture was washed three times with deionized water and dried in an oven at 60 °C for 24 h to obtain modified cellulose nanofibers. The mass ratio of cellulose nanofibers, deionized water, ethanol and tetraethoxysilane was 1.2:40:100:1. A2. Mix modified cellulose nanofibers, tannic acid, and deionized water evenly, stir at 70℃ for 30 min, add palygorskite nanofibers, continue stirring for 30 min, remove, and dry in an oven at 70℃ for 1 h to obtain composite cellulose nanofibers; the mass ratio of modified cellulose nanofibers, tannic acid, deionized water, and palygorskite nanofibers is 1.5:0.2:100:1.2; A3. The composite cellulose nanofibers, ethanol, and deionized water were mixed evenly, KH550 was added, and the mixture was stirred at 70°C for 3 hours. After cooling to room temperature, the mixture was filtered, washed three times with ethanol, and three times with deionized water. The mixture was then dried in an oven at 70°C for 10 minutes to obtain functionalized composite cellulose nanofibers. The mass ratio of composite cellulose nanofibers, ethanol, deionized water, and KH550 was 1.4:100:40:0.3. A4. Add carboxymethyl chitosan to deionized water and stir at 500 r / min and 25℃ for 40 min. Add citric acid and functionalized composite cellulose nanofibers and stir evenly. Add 0.1 mol / L hydrochloric acid to adjust the pH to 3.5. Stir and react at 60℃ for 2 h. Let stand until a hydrogel is formed. Place the hydrogel under 400 Pa vacuum and -20℃ for 24 h to freeze dry and obtain the skin-friendly modifier. The mass ratio of carboxymethyl chitosan, deionized water, citric acid and functionalized composite cellulose nanofibers is 2.6:150:0.4:0.8.

[0047] Comparative Example 5 The only difference between this comparative example and Example 3 is the preparation of the skin-friendly modifier, as detailed below: The skin-friendly modifier is prepared by the following steps: A1. Cellulose nanofibers were mixed with deionized water and ethanol, ultrasonically dispersed at 40 kHz for 20 min, and the pH was adjusted to 9 by adding 30% ammonia water. Tetraethoxysilane was added, and the mixture was stirred at 300 r / min and 40 °C for 8 h. After filtration, the mixture was washed three times with deionized water and dried in an oven at 60 °C for 24 h to obtain modified cellulose nanofibers. The mass ratio of cellulose nanofibers, deionized water, ethanol and tetraethoxysilane was 1.2:40:100:1. A2. Mix modified cellulose nanofibers, tannic acid, and deionized water evenly, stir at 70℃ for 30 min, add palygorskite nanofibers, continue stirring for 30 min, remove, and dry in an oven at 70℃ for 1 h to obtain composite cellulose nanofibers; the mass ratio of modified cellulose nanofibers, tannic acid, deionized water, and palygorskite nanofibers is 1.5:0.2:100:1.2; A3. The composite cellulose nanofibers, ethanol, and deionized water were mixed evenly, KH550 was added, and the mixture was stirred at 70°C for 3 hours. After cooling to room temperature, the mixture was filtered, washed three times with ethanol, and three times with deionized water. The mixture was then dried in an oven at 70°C for 10 minutes to obtain functionalized composite cellulose nanofibers. The mass ratio of composite cellulose nanofibers, ethanol, deionized water, and KH550 was 1.4:100:40:0.3. A4. Sodium carboxymethyl cellulose was added to deionized water and stirred at 500 r / min and 25℃ for 40 min. Citric acid and functionalized composite cellulose nanofibers were added and stirred evenly. Hydrochloric acid with a concentration of 0.1 mol / L was added to adjust the pH to 3.5. The mixture was stirred at 60℃ for 2 h and allowed to stand until a hydrogel was formed. The hydrogel was then freeze-dried at 400 Pa vacuum and -20℃ for 24 h to obtain a skin-friendly modifier. The mass ratio of sodium carboxymethyl cellulose, deionized water, citric acid, and functionalized composite cellulose nanofibers was 2.6:150:0.4:0.8.

[0048] The performance of the skin-friendly blended denim fabrics prepared in Examples 1-3 and Comparative Examples 1-5 was then tested.

[0049] The skin-friendly properties of blended denim are indicated by measuring its moisture-wicking properties, antibacterial properties, and hand feel.

[0050] Moisture wicking performance test: The moisture wicking performance of denim was tested according to the national standard GB / T21655.1-2023 "Evaluation of moisture absorption and quick-drying properties of textiles - Part 1: Single-item combination test method". The wicking height and moisture permeability are two indicators reflecting the effectiveness of the skin-friendly blended denim in wicking performance. Moisture permeability was measured according to GB / T12704.1-2009 EN standard; wicking height was measured according to FZ / T01071-2008 standard.

[0051] Hand feel evaluation: Five professionals scored the hand feel of the prepared skin-friendly blended denim fabric. The scores were then averaged, with 5 being the best and 1 being the worst. Evaluation criteria: 5 points: Soft and smooth, fluffy and full, completely non-sticky and non-itchy, extremely comfortable against the skin, and excellent elasticity when pinched and folded; 4 points: Soft and smooth overall, slightly dry, does not affect skin-friendliness, non-sticky and non-itchy, and good elasticity; 3 points: Moderate softness and hardness, slightly rough, not scratchy, basically dry, and moderate elasticity, suitable for regular wear; 2 points: Hard hand feel, obvious friction, slightly sticky / scratching, and poor elasticity; 1 point: Stiff and rough hand feel, scratchy and sticky, poor skin-friendliness, no elasticity when pinched and folded, and severely stiff.

[0052] Antibacterial performance test: The antibacterial performance of the skin-friendly blended denim fabric prepared above was determined according to GB / T20944.3-2008 standard. The test bacteria were Gram-negative bacteria - Escherichia coli and Gram-positive bacteria - Staphylococcus aureus.

[0053] As shown in Table 1 below.

[0054] Table 1. Performance testing of skin-friendly blended denim fabrics prepared in Examples 1-3 and Comparative Examples 1-5

[0055] As can be seen from the data in Table 1, the skin-friendly blended denim fabrics prepared in Examples 1-3 have high moisture absorption and wicking properties, antibacterial properties, and softness.

[0056] In Comparative Example 1, the modified cellulose nanofibers were replaced with a skin-friendly modifier prepared from cellulose nanofibers to prepare skin-friendly blended denim. The skin-friendly properties decreased, demonstrating that the porous silica layer formed on the surface of the cellulose nanofibers has a high adsorption capacity, which can be used to adsorb and slowly release sweat, giving the denim better absorption and wicking function, improving the skin-friendly properties of the blended denim, and avoiding poor sweat wicking, slow drying after wetting, stickiness to the skin, and heavy wearing. Moreover, the sweat adsorbed in the porous silica can be dispersed into the interior of the denim through the cellulose nanofibers and diffused in all directions along the warp and weft yarns to complete the wicking, avoiding sweat concentration. The denim's limited wicking effect creates a sticky feeling on the skin surface, affecting the skin-friendly properties.

[0057] In Comparative Example 2, the skin-friendly modifier prepared by replacing the composite cellulose nanofibers with modified cellulose nanofibers was used to prepare skin-friendly blended denim. Its skin-friendly properties decreased, which proved that the nanofiber palygorskite formed a multi-layered composite nanofiber by uniformly coating the surface of the modified cellulose nanofibers with tannins. It has a high adsorption capacity and can absorb more sweat, which is diffused into the denim through the nanofibers, thus improving the skin-friendly properties of the denim. Moreover, the nanofiber palygorskite is fixed on the surface of the cellulose nanofibers, avoiding the agglomeration of the nanofiber palygorskite. It is difficult to disperse evenly when directly added to the finishing agent, which affects the water absorption and perspiration performance.

[0058] In Comparative Example 3, the skin-friendly modifier prepared by replacing the functionalized composite cellulose nanofibers with the composite cellulose nanofibers was used to prepare skin-friendly blended denim fabric. The skin-friendly properties decreased, which proved that the grafting of aminosilane on the surface of the composite nanofibers provides active functional groups on the surface of the composite nanofibers. This is beneficial for embedding the composite nanofibers into the aerogel structure, so that the composite nanofibers are uniformly dispersed on the surface of the denim fabric, thereby improving the skin-friendly properties of the denim fabric.

[0059] In Comparative Example 4, sodium carboxymethyl cellulose was replaced with carboxymethyl chitosan by mass, and in Comparative Example 5, carboxymethyl chitosan was replaced with sodium carboxymethyl cellulose by mass. These skin-friendly modifiers were used to prepare skin-friendly blended denim fabric. The decrease in the amount of skin-friendly modifiers showed that the aerogel surface formed by carboxymethyl cellulose and chitosan has high activity and can be uniformly dispersed in the skin-friendly finishing agent. This allows the skin-friendly modifier to be uniformly attached to the denim surface, improving the denim's absorbency and sweat-wicking properties. Furthermore, a hydrophilic aerogel layer is formed on the denim surface, which can absorb sweat into the three-dimensional network structure of the aerogel for storage and conduction. This solves the problem that traditional hydrophilic finishing makes the denim surface hydrophilic, causing sweat to remain on the denim surface and directly contact the skin, resulting in a sticky feeling on the skin surface and affecting the skin-friendly properties. In addition, the organic aerogel prepared with carboxymethyl cellulose and chitosan has good antibacterial activity and softness, improving the antibacterial and soft properties of the denim.

[0060] In the description of this specification, the references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0061] The above description is merely an example and illustration of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described, or use similar methods to replace them, as long as they do not deviate from the invention or exceed the scope defined in the claims, all of which should fall within the protection scope of the present invention.

Claims

1. A method for making a skin-friendly blended denim, characterized in that, Includes the following steps: S1. Mix the blended denim fabric, sodium hydroxide solution and sodium bicarbonate solution evenly, heat treat, remove, wash and dry to obtain pretreated blended denim fabric. S2. Mix polyacrylate emulsion, polyether-modified silicone oil, skin-friendly modifier and deionized water, stir evenly to obtain skin-friendly finishing agent; S3. Immerse the pretreated blended denim fabric in a skin-friendly finishing agent and treat it at 50-60℃ for 30-40 minutes. Take it out and bake it at 80-100℃ for 3-5 minutes to obtain a skin-friendly blended denim fabric. The skin-friendly modifier is obtained by surface treatment of composite nanofibers with aminosilane, followed by mixing and reaction with sodium carboxymethyl cellulose and carboxymethyl chitosan. The composite nanofibers are obtained by synthesizing a porous silica layer on the surface of cellulose nanofibers, and then reacting it with tannic acid and palygorskite nanofibers.

2. The method for preparing a skin-friendly blended denim fabric according to claim 1, characterized in that, The skin-friendly modifier is prepared by the following steps: A1. Cellulose nanofibers were mixed with deionized water and ethanol, ultrasonically dispersed, and then ammonia was added to adjust the pH. Tetraethoxysilane was then added, and after stirring and reaction, the mixture was filtered, washed, and dried to obtain modified cellulose nanofibers. A2. Mix the modified cellulose nanofibers, tannic acid and deionized water evenly, stir, add the nanofiber palygorskite, continue stirring, take out and dry to obtain composite cellulose nanofibers. A3. Mix the composite cellulose nanofibers, ethanol and deionized water evenly, add silane coupling agent, stir and react, cool to room temperature, filter, wash and dry to obtain functionalized composite cellulose nanofibers. A4. Add sodium carboxymethyl cellulose and carboxymethyl chitosan to deionized water, stir evenly, add citric acid and functionalized composite cellulose nanofibers, stir evenly, add hydrochloric acid to adjust pH, stir to react, let stand until a hydrogel is formed, freeze-dry the hydrogel to obtain the skin-friendly modifier.

3. The method for preparing a skin-friendly blended denim fabric according to claim 2, characterized in that, In step A1, the mass ratio of the cellulose nanofibers, deionized water, ethanol and tetraethoxysilane is (1-1.2):(30-40):(90-100):(0.8-1).

4. The method for preparing a skin-friendly blended denim fabric according to claim 2, characterized in that, In step A2, the mass ratio of the modified cellulose nanofibers, tannic acid, deionized water and nanofiber palygorskite is (1.2-1.5):(0.1-0.2):(80-100):(1-1.2).

5. The method for preparing a skin-friendly blended denim fabric according to claim 2, characterized in that, In step A3, the mass ratio of the composite cellulose nanofibers, ethanol, deionized water and silane coupling agent is (1.2-1.4):(90-100):(30-40):(0.1-0.3).

6. The method for preparing a skin-friendly blended denim fabric according to claim 2, characterized in that, In step A4, the mass ratio of sodium carboxymethyl cellulose, carboxymethyl chitosan, deionized water, citric acid, and functionalized composite cellulose nanofibers is (1-1.2):(1.2-1.4):(120-150):(0.2-0.4):(0.5-0.8).

7. The method for preparing a skin-friendly blended denim fabric according to claim 1, characterized in that, In step S1, the heat treatment temperature is 70-80℃ and the heat treatment time is 15-20 min; In step S1, the mass ratio of the blended denim fabric, sodium hydroxide solution, and sodium bicarbonate solution is 1:(8-10):(18-22); In step S1, the concentration of the sodium hydroxide solution is 5-10 g / L, and the concentration of the sodium bicarbonate solution is 10-15 g / L.

8. The method for preparing a skin-friendly blended denim fabric according to claim 1, characterized in that, In step S2, the mass ratio of the polyacrylate emulsion, polyether-modified silicone oil, skin-friendly modifier, and deionized water is (0.2-0.4):(0.1-0.3):(1-2):(80-100).

9. The method for preparing a skin-friendly blended denim fabric according to claim 1, characterized in that, In step S3, the bath ratio of the pretreated blended denim fabric to the skin-friendly finishing agent is 1:(30-50).

10. A skin-friendly blended denim fabric prepared by the method of any one of claims 1-9.

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