A method for preparing nonwoven cooling cellulose fibers

Abstract

This invention discloses a method for preparing cool-feeling cellulose fibers for nonwoven fabrics, comprising the following steps: (1) weighing a whitening agent and adding it to soft water, then adding a dispersant and grinding and dispersing it thoroughly, and filtering it to obtain a whitening dispersion; (2) preparing a cellulose spinning solution using cellulose pulp as raw material, adding the whitening dispersion to the spinning solution to obtain a blended spinning solution; (3) spinning the blended spinning solution in a low-temperature, low-concentration coagulation bath, and obtaining a shaped filament bundle after stretching, and then cutting it into short fibers; (4) subjecting the short fibers to high-temperature cotton web laying, acid washing, water washing, desulfurization, bleaching, swelling mercerizing, cool-feel finishing, oiling, and drying steps to obtain the cool-feeling cellulose fibers for nonwoven fabrics. The cool-feeling cellulose fibers prepared by the method of this invention have high whiteness, low residual sulfur content, low water-soluble matter, and long-lasting cool-feeling performance, which can fully meet the special requirements of nonwoven nonwoven fabric fields such as medical and health care.

Description

Technical Field

[0001] This invention relates to the field of cellulose fiber technology, and in particular to a method for preparing a nonwoven cool-feeling cellulose fiber. Background Technology

[0002] Cellulose fibers possess a range of properties that synthetic fibers cannot fully match, including excellent skin-friendliness, moisture absorption, ease of finishing, comfort, and biodegradability. As a raw material for nonwoven fabrics, they have unique applications in medical, nursing, hygiene, and cosmetic products. When synthetic fibers are used in nonwoven fabric production, their relatively low elongation at break causes the fiber bundles to easily disperse during the high-pressure water jetting process, affecting nonwoven production and product quality. Therefore, when using synthetic fibers as raw materials, resins or adhesives must be used to prevent the spunlace fiber bundles from becoming loose.

[0003] Cellulose fiber-based nonwoven fabrics are soft to the touch, strong, and have good moisture absorption and breathability. They are increasingly used as disposable daily necessities in the hot summer. Traditional nonwoven cellulose fibers are produced using conventional cellulose fiber production processes, and their product performance and indicators cannot meet the requirements of medical and sanitary materials. The cooling function of nonwoven fabrics is generally achieved by applying auxiliaries to the surface of the nonwoven fabric through finishing processes. This method has a low content of functional materials, unsatisfactory effects, and poor durability. In particular, it requires a lot of investment in equipment, increasing production and investment costs. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a method for preparing nonwoven cooling cellulose fiber in view of the shortcomings of the prior art. While improving the whiteness, water absorption time, and reducing the residual sulfur content and water-soluble matter in the fiber, the method also endows the cellulose fiber with a lasting cooling property, enabling it to be applied in special fields such as medical and health care.

[0005] To solve the above-mentioned technical problems, the technical solution of the present invention is as follows:

[0006] A method for preparing nonwoven cooling cellulose fibers includes the following steps:

[0007] (1) Preparation of whitening dispersion: Weigh the whitening agent and add it to soft water, then add the dispersant and grind and disperse it thoroughly. After filtration, the whitening dispersion is obtained.

[0008] (2) Preparation of blended spinning solution: Cellulose spinning solution is prepared by using cellulose pulp as raw material. The whitening dispersion is added to the spinning solution by pre-spinning injection technology to obtain blended spinning solution; the total mass of whitening agent and dispersant in the whitening dispersion accounts for 0.3 to 0.8 wt% of the content of type A cellulose in the spinning solution.

[0009] (3) Spinning: The blended spinning solution is spun in a low-temperature, low-concentration coagulation bath. The nascent filament bundles are drawn to obtain shaped filament bundles, which are then cut into short fibers.

[0010] (4) Post-treatment: The short fibers are subjected to high-temperature cotton web laying, desulfurization, bleaching, expansion mercerizing, pickling, cooling finishing, oiling and drying to obtain the nonwoven cooling cellulose fiber; the liquid content of the fiber during the cooling finishing is 50-55 wt%, the concentration of the cooling finishing agent is 3-5 wt%, the temperature is 40-55℃ and the finishing time is 5-10 min.

[0011] As an improved technical solution, the whitening agent in the whitening dispersion is rutile titanium dioxide, and the dispersant is either sodium hexametaphosphate or Klein DIP; the content of rutile titanium dioxide in the whitening dispersion is 5-10 wt%; and the amount of dispersant added is 0.005-0.01 wt% of rutile titanium dioxide.

[0012] As an improved technical solution, in step (1), the filtration adopts a membrane filtration method of vacuum filtration, and the particle size D90 of the filtered whitening dispersion is ≤1.5μm.

[0013] As an improved technical solution, the low-temperature, low-concentration coagulation bath contains 80-95 g / L sulfuric acid, 15-25 g / L zinc sulfate, and 280-300 g / L sodium sulfate, at a temperature of 35-42°C.

[0014] As an improved technical solution, the temperature of the high-temperature cotton-laying web is ≥98℃, and the high temperature is used to evaporate and recover carbon disulfide, thereby reducing the sulfide content in the finished fiber.

[0015] As an improved technical solution, the swelling agent in the expanded mercerizing process is caustic soda, and the concentration of caustic soda is 180-220 g / L, the temperature is 35-40℃, the time is 3-8 min, and the fiber liquid content is 55-60 wt%.

[0016] As an improved technical solution, the pickling is performed using lactic acid or citric acid, with an acid concentration of 4–8 g / L and a temperature of 40–55°C. A weak acid that causes less damage to the fibers is used, reacting with metal ions in the fibers to reduce the content of soluble substances in water and improve fiber whiteness.

[0017] As an improved technical solution, the cooling finishing agent is Iceman Cool, which is mainly composed of xylitol, erythritol, and silk protein and has a cooling and moisturizing function.

[0018] As an improved technical solution, the spinning solution contains 8.8–9.5 wt% methyl cellulose, 4.5–5.5 wt% sodium hydroxide, and has a viscosity of 40–55 s (falling ball viscosity method).

[0019] As an improved technical solution, the post-processing steps further include a water washing step after each of the high-temperature cotton web laying, desulfurization, bleaching, and expanded mercerizing finishing. The specific post-processing steps are as follows: high-temperature cotton web laying, water washing, desulfurization, water washing, bleaching, water washing, expanded mercerizing finishing, water washing, acid washing, cooling finishing, oiling, drying, fine opening, and packaging.

[0020] The gap between the fine opening roller and the holding roller is 6-10mm. The gap is adjusted through experiments to increase the fluffiness of the fibers and achieve a rapid water absorption effect.

[0021] As an improved technical solution, both the pickling and water washing processes use deionized water, with a water washing temperature of 75–85°C and a water volume of 45–50 ml. 3 / h.

[0022] As an improved technical solution, the desulfurization is carried out at a sodium hydroxide concentration of 4.0-5.0 g / L, a temperature of 80-90℃, and a time of 5-8 min.

[0023] As an improved technical solution, the fibers before the cooling treatment are weakly acidic, with a pH value of 4 to 6.

[0024] Due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0025] The method for preparing nonwoven cooling cellulose fibers of the present invention involves co-mixing a whitening dispersion into the spinning solution to improve fiber whiteness. Spinning is performed using a low-temperature, low-concentration coagulation bath, and a low-temperature, low-concentration molding process results in a high elongation at break. The fibers possess good extensibility and toughness, allowing for significant deformation under stress without breakage. Therefore, resins or adhesives are not required in the production of spunlace nonwoven fabrics. Post-treatment includes high-temperature web laying, desulfurization, and multiple washings, resulting in low residual sulfur and low water-soluble content in the fibers. In particular, the cooling finishing process after expansion mercerizing involves swelling of the cellulose fibers, causing rearrangement of the cellulose macromolecular chains and improving the fiber's adsorption capacity for cooling agents. Therefore, the fiber absorbs more cooling agents, resulting in a longer-lasting cooling effect. The nonwoven cooling cellulose fiber prepared by the method of this invention has excellent quick-wetting properties, high whiteness, low residual sulfur content, low water-soluble matter, and long-lasting cooling properties. It can fully meet the special requirements of nonwoven nonwoven fabric fields such as medical and health care. Moreover, compared with the cooling finishing process in nonwoven fabric weaving, the cooling properties are better and more durable, and the equipment investment in nonwoven fabric production is reduced.

[0026] The nonwoven cooling cellulose fiber prepared by the method of this invention has a water absorption time that is more than 5 seconds longer and a whiteness that is more than 5% higher than that of conventional cellulose fiber (according to GB / T14463-2022 "Viscose Staple Fiber"). The residual sulfur content is ≤3.0 mg / 100g, the water-soluble matter content is ≤0.4%, and the elongation at break is ≥21%. All these indicators are higher than the relevant indicators in medical YY / T0921-2015 "Medical Absorbent Viscose Fiber". The contact cooling coefficient is ≥0.15 J / (cm²). 2 (GB / T 35263-2017 "Test and Evaluation of Cooling Performance of Textiles Upon Contact"). Nonwoven fabrics produced using this material have a mechanical strength exceeding 90% of that of textiles and can be used to replace textiles in many fields.

[0027] The nonwoven cooling cellulose fiber prepared by the method of this invention undergoes dual treatment of mercerizing and cooling finishing, resulting in a more comfortable and smooth feel. Upon contact with the skin, it can cause rapid heat loss from the skin surface, providing a long-lasting cooling effect. It is suitable not only for nonwoven fabrics in the medical and hygiene fields, but also for cosmetics such as face masks.

[0028] In the post-processing steps of this invention, an acid washing step is added before the puffing finishing. After acid washing, the fiber before the cooling finishing is weakly acidic, with a pH value of 4 to 6. This is because the inventors of this application found through extensive theoretical analysis and experimental verification that the cooling finishing effect is better and the cooling coefficient of the finished fiber is higher under weakly acidic conditions. Detailed Implementation

[0029] The following specific embodiments further illustrate the present invention. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0030] Example 1

[0031] Preparation of whitening solution: Weigh out rutile titanium dioxide as a whitening agent and add it to soft water. Then add sodium hexametaphosphate as a dispersant and grind and disperse it thoroughly. After filtration, a whitening dispersion is obtained. The content of rutile titanium dioxide in the whitening dispersion is 6 wt%. The amount of dispersant added is 0.0065 wt% of rutile titanium dioxide.

[0032] Blending: A cellulose spinning solution was prepared from cellulose pulp as raw material, wherein the spinning solution contained 9.0 wt% methyl cellulose, 4.9 wt% sodium hydroxide, and a viscosity of 42 s; the whitening dispersion was added to the spinning solution using pre-spinning injection technology to obtain a blended spinning solution; the total mass of the whitening agent and dispersant in the whitening dispersion accounted for 0.35 wt% of the methyl cellulose content in the spinning solution;

[0033] Spinning: The blended spinning solution is spun in a low-temperature, low-concentration coagulation bath containing 85 g / L sulfuric acid, 18 g / L zinc sulfate, and 285 g / L sodium sulfate at a temperature of 38°C. The nascent filament bundle is drawn to obtain a shaped filament bundle, which is then cut into short fibers.

[0034] Post-processing: The short fibers are subjected to the following steps: high-temperature 99°C cotton web laying, washing, desulfurization, washing, bleaching, washing, expanded mercerizing, washing, acid washing, cooling finishing, oiling, drying, fine opening, and packaging to obtain the nonwoven cooling cellulose fiber.

[0035] The swelling agent used in the expanded mercerizing process is caustic soda, with a concentration of 192 g / L, a temperature of 37°C, a time of 8 min, and a fiber liquid content of 56 wt%.

[0036] The pH value of the fiber before the cooling finish was 5.0; during the cooling finish, the liquid content of the fiber was 52wt%, the concentration of the cooling finish agent Iceman Cool was 3.5wt%, the temperature was 52℃, and the finishing time was 6min.

[0037] Example 2

[0038] Preparation of whitening solution: Weigh out rutile titanium dioxide as a whitening agent and add it to soft water. Then add Klein DIP dispersant and grind and disperse thoroughly. After filtration using a vacuum filtration membrane, a whitening dispersion with a particle size D90 ≤ 1.5 μm is obtained. The rutile titanium dioxide content in the whitening dispersion is 8 wt%. The amount of dispersant added is 0.009 wt% of the rutile titanium dioxide.

[0039] Blending: A cellulose spinning solution was prepared from cellulose pulp as raw material, wherein the spinning solution contained 9.2 wt% methyl cellulose, 5.3 wt% sodium hydroxide, and a viscosity of 52 s; the whitening dispersion was added to the spinning solution using pre-spinning injection technology to obtain a blended spinning solution; the total mass of the whitening agent and dispersant in the whitening dispersion accounted for 0.6 wt% of the methyl cellulose content in the spinning solution;

[0040] Spinning: The blended spinning solution is spun in a low-temperature, low-concentration coagulation bath containing 93 g / L sulfuric acid, 22 g / L zinc sulfate, and 296 g / L sodium sulfate at a temperature of 40°C. The nascent filament bundle is drawn to obtain a shaped filament bundle, which is then cut into short fibers.

[0041] Post-processing: The short fibers are subjected to the following steps: high-temperature 100°C cotton web laying, washing, desulfurization, washing, bleaching, washing, expanded mercerizing, washing, acid washing, cooling finishing, oiling, drying, fine opening, and packaging to obtain the nonwoven cooling cellulose fiber.

[0042] The swelling agent used in the expanded mercerizing process is caustic soda, with a concentration of 210 g / L, a temperature of 38°C, a time of 5 min, and a fiber liquid content of 56 wt%.

[0043] The pH value of the fiber before the cooling finish was 4.8; the liquid content of the fiber during the cooling finish was 54wt%, the concentration of the cooling finish agent Iceman Cool was 4wt%, the temperature was 44℃, and the finishing time was 9min.

[0044] The pickling was performed using lactic acid at a concentration of 6.5 g / L and a temperature of 52°C.

[0045] Both the pickling and rinsing processes used deionized water, with a rinsing temperature of 82℃ and a water volume of 46m³. 3 / h;

[0046] The desulfurization process involved a sodium hydroxide concentration of 4.6 g / L, a temperature of 85°C, and a time of 8 minutes.

[0047] The gap between the fine opening cotton opening roller and the holding roller is 8mm.

[0048] Example 3

[0049] Preparation of whitening solution: Weigh out rutile titanium dioxide as a whitening agent and add it to soft water. Then add sodium hexametaphosphate as a dispersant and grind and disperse it thoroughly. After filtration using a vacuum filtration membrane, a whitening dispersion with a particle size D90 ≤ 1.5 μm is obtained. The content of rutile titanium dioxide in the whitening dispersion is 7.5 wt%. The amount of dispersant added is 0.008 wt% of the rutile titanium dioxide.

[0050] Blending: A cellulose spinning solution was prepared from cellulose pulp as raw material, wherein the spinning solution contained 9.0 wt% alpha-cellulose, 5.0 wt% sodium hydroxide, and a viscosity of 51 s; the whitening dispersion was added to the spinning solution using pre-spinning injection technology to obtain a blended spinning solution; the total mass of the whitening agent and dispersant in the whitening dispersion accounted for 0.45 wt% of the alpha-cellulose content in the spinning solution;

[0051] Spinning: The blended spinning solution is spun in a low-temperature, low-concentration coagulation bath containing 88 g / L sulfuric acid, 20 g / L zinc sulfate, and 292 g / L sodium sulfate at a temperature of 39°C. The nascent filament bundle is drawn to obtain a shaped filament bundle, which is then cut into short fibers.

[0052] Post-processing: The short fibers are subjected to the following steps: high-temperature 100°C cotton web laying, washing, desulfurization, washing, bleaching, washing, expansion mercerizing, washing, acid washing, cooling finishing, oiling, drying, fine opening, and packaging to obtain the nonwoven cooling cellulose fiber a.

[0053] The swelling agent used in the expanded mercerizing process is caustic soda, with a concentration of 205 g / L, a temperature of 37°C, a time of 5 min, and a fiber liquid content of 58 wt%.

[0054] The pH value of the fiber before the cooling finish was 5.2; the liquid content of the fiber during the cooling finish was 53wt%, the concentration of the cooling finish agent Iceman Cool was 4.5wt%, the temperature was 42℃, and the finishing time was 6min.

[0055] The pickling was performed using citric acid at a concentration of 6 g / L at a temperature of 53°C.

[0056] Both the pickling and rinsing processes used deionized water, with a rinsing temperature of 80℃ and a water volume of 48m³. 3 / h;

[0057] The desulfurization process involved a sodium hydroxide concentration of 4.4 g / L, a temperature of 88°C, and a time of 6 min.

[0058] The gap between the fine opening cotton opening roller and the holding roller is 7mm.

[0059] Comparative Example 1

[0060] Comparative Example 1 and Example 3 are identical in terms of the preparation of the whitening solution, blending, and spinning. The difference lies in the post-processing steps, which do not include the expansion and mercerizing step. The post-processing steps are as follows:

[0061] The short fibers are subjected to the following steps: high-temperature sizing at 100°C, washing, desulfurization, washing, bleaching, washing, acid washing, cooling finishing, oiling, drying, fine opening, and packaging, to obtain the nonwoven cooling cellulose fiber d1; the process parameters for each step are the same as in Example 3.

[0062] Comparative Example 2

[0063] Compared with Example 3, Comparative Example 2 had the same steps in whitening solution preparation, blending, and spinning. The difference was that in the post-treatment steps, the swelling mercerizing treatment and the cooling finishing steps were performed simultaneously. The post-treatment steps were as follows:

[0064] The short fibers are subjected to the following steps: high-temperature sizing at 100°C, washing, desulfurization, bleaching, washing, acid washing, expansion mercerizing and cooling finishing, washing, oiling, drying, fine opening, and packaging, to obtain the nonwoven cooling cellulose fiber d2.

[0065] The finishing solution for the expanded mercerizing and cooling finishing contains 205 g / L of the expanding agent caustic soda and 4.5 wt% of the cooling finishing agent Iceman Cool. The treatment solution temperature is 40°C, the time is 10 min, and the fiber liquid content is 58 wt%.

[0066] The process parameters for the remaining processing steps are the same as in Example 3.

[0067] Comparative Example 3

[0068] Comparative Example 3 and Example 3 are identical in terms of the preparation of the whitening solution, blending, and spinning steps. The difference lies in the post-treatment steps: a cooling finish is performed first, followed by a swelling and mercerizing treatment. The post-treatment steps are as follows:

[0069] The short fibers are subjected to the following steps: high-temperature web laying at 100°C, washing, desulfurization, washing, bleaching, washing, acid washing, cooling finishing, washing, expanded mercerizing finishing, washing, oiling, drying, fine opening, and packaging, to obtain the nonwoven cooling cellulose fiber d3. The process parameters for each step are the same as in Example 3.

[0070] Comparative Example 4

[0071] Comparative Example 4 is identical to Example 3 in terms of the preparation of the whitening solution, blending, and spinning steps. The difference lies in the post-treatment steps, where the acid washing step is omitted before the expansion and mercerizing treatment step. The post-treatment steps are as follows:

[0072] The process involves high-temperature cotton web laying, washing, desulfurization, washing, bleaching, washing, expanded mercerizing, washing, cooling finishing, oiling, drying, fine opening, and packaging to obtain the nonwoven cellulose fiber d4.

[0073] In the post-processing, since the acid washing step is omitted, the pH value of the fiber before the cooling finish is 7.8; the other process parameters are the same as in Example 3.

[0074] Comparative Example 5

[0075] Comparative Example 5 is identical to Example 3 in terms of the preparation of the whitening solution, blending, and spinning steps. The difference lies in the post-treatment steps, which do not include the cooling finishing and swelling mercerizing steps. The post-treatment steps are as follows:

[0076] The short fibers are subjected to a series of steps including high-temperature web laying at 100°C, washing, desulfurization, washing, bleaching, washing, oiling, drying, fine opening, and packaging to obtain the nonwoven cellulose fiber d5. The process parameters for each step are the same as in Example 3.

[0077] The cooling cellulose fibers prepared in Examples 1-3 and Comparative Examples 1-4 were evaluated according to GB / T14463-2022 "Viscose Staple Fiber" and GB / T 35263-2017 "Test and Evaluation of Cooling Properties of Textiles Upon Contact", and their physical and mechanical properties and cooling coefficients are shown in Table 1.

[0078] Table 1

[0079]

[0080]

[0081] Test case

[0082] The cooling fiber samples (a, d1, d2, d3, d5) from Examples 3 and Comparative Examples 1-4 were woven into nonwoven fabrics according to conventional spunlace nonwoven fabric production processes. The specific process steps are as follows:

[0083] Fiber raw material → opening and mixing → carding into web → pre-wetting → hydroentanglement on both sides → bulking and mercerizing treatment → acid washing → washing → cooling finishing → drying → winding

[0084] Then, using the cellulose fiber d5 prepared in Comparative Example 5, nonwoven fabric was woven according to the conventional spunlace nonwoven fabric production process. In the post-treatment steps, it successively underwent a swelling mercerizing treatment and a cooling finishing step. The treatment process for the cooling finishing and swelling mercerizing treatment was the same as in Example 3: the swelling agent for the swelling mercerizing treatment was caustic soda, the concentration of caustic soda was 205 g / L, the temperature was 37°C, the time was 5 min, and the liquid volume was 58 wt%; the liquid volume for the cooling finishing was 53 wt%, the concentration of the cooling finishing agent Iceman Cool was 4.5 wt%, the temperature was 42°C, and the finishing time was 6 min.

[0085] The nonwoven fabrics woven from the above cooling fiber samples (a, d1, d2, d3, d4) and cellulose fiber (d5) were tested according to GB / T35263-2017 "Test and Evaluation of Instantaneous Cooling Performance of Textiles". The contact cooling coefficient and the durability of the cooling sensation are shown in Table 2.

[0086] Table 2

[0087]

[0088] From the above embodiments, comparative examples, and experimental examples, it can be concluded that in the post-processing steps, interchangeing or merging the mercerizing and cooling finishing steps, or omitting any step, will significantly reduce the cooling properties of the resulting fibers. This is especially true for the durability of the cooling effect after weaving into nonwoven fabric. Furthermore, fibers that undergo cooling finishing under neutral conditions without omitting the acid washing step before cooling finishing exhibit the worst cooling coefficient and cooling durability. In conventional spunlace nonwoven fabric processes, even using the cooling finishing steps of this invention, the nonwoven fabric produced after the same pre-expansion treatment, acid washing, and subsequent cooling finishing not only has a significantly lower cooling coefficient than the nonwoven fabric woven with the cooling fibers of this invention, but also exhibits a less than ideal cooling durability.

Claims

1. A method for preparing nonwoven cooling cellulose fibers, characterized in that... Includes the following steps: (1) Preparation of whitening dispersion: Weigh the whitening agent and add it to soft water, then add the dispersant and grind and disperse it thoroughly. After filtration, the whitening dispersion is obtained. (2) Preparation of blended spinning solution: Cellulose spinning solution is prepared by using cellulose pulp as raw material, and the whitening dispersion is added to the spinning solution to obtain blended spinning solution; the total mass of whitening agent and dispersant in the whitening dispersion accounts for 0.3 to 0.8 wt% of the content of type A cellulose in the spinning solution; (3) Spinning: The blended spinning solution is spun in a low-temperature, low-concentration coagulation bath. The nascent filament bundles are drawn to obtain shaped filament bundles, which are then cut into short fibers. (4) Post-treatment: The short fibers are subjected to high-temperature cotton web laying, desulfurization, bleaching, expansion mercerizing, pickling, cooling finishing, oiling, and drying to obtain the nonwoven cooling cellulose fiber; the fiber before cooling finishing is weakly acidic with a pH value of 4 to 6; during cooling finishing, the fiber liquid content is 50 to 55 wt%, the cooling finishing agent concentration is 3 to 5 wt%, the temperature is 40 to 55℃, and the finishing time is 5 to 10 min.

2. The method for preparing nonwoven cooling cellulose fibers as described in claim 1, characterized in that: The whitening agent in the whitening dispersion is rutile titanium dioxide, and the dispersant is either sodium hexametaphosphate or Klein DIP; the content of rutile titanium dioxide in the whitening dispersion is 5-10 wt%. The amount of dispersant added is 0.005 to 0.01 wt% of rutile titanium dioxide.

3. The method for preparing nonwoven cooling cellulose fibers as described in claim 1, characterized in that: The low-temperature, low-concentration coagulation bath contains 80–95 g / L sulfuric acid, 15–25 g / L zinc sulfate, and 280–300 g / L sodium sulfate, at a temperature of 35–42°C.

4. The method for preparing nonwoven cooling cellulose fibers as described in claim 1, characterized in that: The temperature of the high-temperature cotton quilt is ≥98℃.

5. The method for preparing nonwoven cooling cellulose fibers as described in claim 1, characterized in that: The swelling agent used in the expanded mercerizing process is caustic soda, with a concentration of 180–220 g / L, a temperature of 35–40°C, a time of 3–8 min, and a fiber liquid content of 55–60 wt%.

6. The method for preparing nonwoven cooling cellulose fibers as described in claim 1, characterized in that: The pickling process uses lactic acid or citric acid, with an acid concentration of 4–8 g / L and a temperature of 40–55 °C.

7. The method for preparing nonwoven cooling cellulose fibers as described in claim 1, characterized in that: The cooling finishing agent is Iceman Cool.

8. The method for preparing nonwoven cooling cellulose fibers as described in claim 1, characterized in that: The spinning solution contains 8.8–9.5 wt% methyl cellulose, 4.5–5.5 wt% sodium hydroxide, and has a viscosity of 40–55 s.

9. The method for preparing nonwoven cooling cellulose fibers as described in claim 1, characterized in that: The post-processing steps also include a water washing step after the high-temperature cotton web laying, desulfurization, bleaching, and expanded mercerizing finishing.

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