A method for preparing highly water-absorbent microporous regenerated cellulose fiber

Abstract

The present invention belongs to the field of regenerated cellulose fiber manufacturing and specifically discloses a pore-forming agent for preparing highly absorbent microporous regenerated cellulose fibers. The preparation method of the pore-forming agent comprises: immersing an inorganic carbonate in a solvent, adding an anionic surfactant, and then immersing and compounding at 0-10°C for 5-30 minutes, followed by solid-liquid separation. The resulting solid is the pore-forming agent. The present invention also discloses a method for preparing highly absorbent microporous regenerated cellulose fibers, comprising adding the pore-forming agent to a spinning solution prepared from cellulose pulp, stirring and mixing the solution uniformly, and then degassing the solution to obtain a composite spinning solution; extruding the composite spinning solution from a spinneret into a coagulation bath containing a cationic surfactant, where the solution precipitates in the coagulation bath to obtain microporous fiber strands; and post-treating the microporous fiber strands to obtain highly absorbent microporous regenerated cellulose.

Description

Technical Field

[0001] The invention belongs to the field of regenerated cellulose fiber manufacturing and relates to a preparation method of highly water-absorbent microporous regenerated cellulose fiber. Background Art

[0002] Viscose fiber is a regenerated cellulose fiber made from natural cellulose (such as wood and cotton linters) through chemical treatment and spinning. The production process primarily involves preparing cellulose pulp (dissolving pulp), alkalizing it, xantholysis, dissolving it, maturing it, and filtering it. The resulting spinning solution is then deaerated, ejected from the spinneret, and precipitated into strands in a coagulation bath. The strands then undergo appropriate post-processing. The resulting fibers are virtually free of micropores.

[0003] Viscose fiber, with its excellent hygroscopicity and biocompatibility, has become a core material for medical and sanitary products. Due to its cost-effective raw material, good skin affinity, and biodegradability, it is gradually replacing cotton fiber and is widely used in personal hygiene textiles (such as facial wipes, face towels, cotton pads, sanitary napkins, adult incontinence care pads, etc.) and medical textiles (gauze and wound dressings). These applications are increasingly demanding fiber materials with high fluid absorption (including water and blood absorption). However, the dense surface layer of conventional viscose fiber hinders rapid liquid penetration, resulting in a limited water absorption capacity. Therefore, the development of highly absorbent viscose fiber has broad application prospects.

[0004] In order to improve the water absorption performance of viscose fiber non-woven products, the industry has achieved this through fiber modification, blending or post-finishing methods. For example, patent CN202411787984.2 improves the hydrophilicity of viscose fiber by modifying cellulose carboxymethylation. However, direct chemical modification of the molecular structure of the fiber will inevitably affect the physical and chemical properties of the fiber and will also cause chemical residues. The literature (Nonwoven Fabrics. 2009, 17 (4): 20-23.) reported a method for processing super absorbent non-woven fabrics by blending ordinary viscose fiber with super absorbent fiber. Although this technology significantly improves the liquid absorption capacity of viscose fiber non-woven products, the introduction of synthetic polymers has disadvantages in terms of environmental degradation performance. Patent CN202410879367.9 reports a method for producing super absorbent non-woven products by combining polymer absorbent resin with fiber. This method belongs to the post-finishing method, which increases the processing steps and raw material usage of viscose non-woven fabrics, thereby increasing production costs. If highly absorbent fibers can be directly processed during the viscose fiber processing stage, it will not only reduce costs but also help the industry save energy and reduce carbon emissions, and is expected to become a key development direction to break through existing technological barriers. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a preparation method of highly water-absorbent microporous regenerated cellulose fiber and the microporous agent used therein.

[0006] In order to solve the above technical problems, the present invention provides a pore-forming agent for preparing highly absorbent microporous regenerated cellulose fibers. The preparation method of the pore-forming agent is as follows:

[0007] Immerse the inorganic carbonate (granular) in a solvent (the solvent completely immerses the inorganic carbonate particles), add an anionic surfactant, and then immerse and compound (compound under static conditions) at 0-10°C for 5-30 minutes (preferably 1-8°C for 8-20 minutes), and then separate the solid and liquid (filter), and the obtained solid is a pore-forming agent (alkali-resistant pore-forming agent);

[0008] The mass ratio of the inorganic carbonate particles to the anionic surfactant is 100: 0.2-1.0 (preferably 100: 0.3-0.8).

[0009] As an improvement of the pore-forming agent of the present invention:

[0010] Inorganic carbonates are magnesium carbonate, zinc carbonate, and barium carbonate;

[0011] The solvent is ethanol with a volume concentration of 90-95%;

[0012] Anionic surfactant is C n Alkyl anionic surfactant, carbon chain length satisfies n≥12.

[0013] As a further improvement of the pore-forming agent of the present invention:

[0014] The anionic surfactant is at least any one of the following: sodium dodecylbenzenesulfonate, sodium hexadecyl sulfate, and sodium octadecylsulfonate.

[0015] As a further improvement of the pore-forming agent of the present invention:

[0016] Weight of inorganic carbonate (g): Volume of solvent (ml) ≤ 1. For example, 100g: 150~180ml.

[0017] The present invention also provides a method for preparing highly water-absorbent microporous regenerated cellulose fibers, comprising preparing a spinning solution (a composite spinning solution in the present invention) from cellulose pulp (cellulose dissolving pulp), spraying the solution from a spinneret and precipitating the solution in a coagulation bath to obtain fiber strands (microporous fiber strands in the present invention); and using the above-mentioned pore-forming agent, sequentially performing the following steps:

[0018] 1) Preparation of composite spinning solution:

[0019] Adding the pore-forming agent to a spinning solution prepared from cellulose pulp (the spinning solution of the prior art) in a weight ratio of cellulose pulp to pore-forming agent = 100:2-15 (preferably 100:3.5-12), stirring and mixing uniformly, and then degassing (vacuum degassing to remove bubbles) to prepare a composite spinning solution;

[0020] 2) In the spinning step: 1-5 g of a cationic surfactant is added to each liter of the coagulation bath (i.e., a cationic surfactant is added at a mass concentration of 1-5 g / L, preferably 2-4 g / L) to obtain a coagulation bath containing a cationic surfactant;

[0021] The composite spinning solution is extruded from a spinneret (aperture size 50-120 μm) into a coagulation bath containing a cationic surfactant, where it precipitates to obtain microporous fiber strands.

[0022] Note: The coagulation bath contains H2SO4 115±5 g / L, Na2SO4 160±5 g / L, and ZnSO4 15±5 g / L; the bath temperature is 50±5 ℃.

[0023] 3) The microporous fiber strips are post-treated to obtain highly water-absorbent microporous regenerated cellulose fibers.

[0024] As an improvement to the preparation method of the highly water-absorbent microporous regenerated cellulose fiber of the present invention: the cationic surfactant is C n Alkyl cationic surfactant, carbon chain length satisfies n≥1.

[0025] As a further improvement to the method for preparing highly water-absorbent microporous regenerated cellulose fibers of the present invention: the cationic surfactant is at least any one of the following: dodecyltrimethylammonium chloride and octadecyltrimethylammonium bromide.

[0026] The conventional production process of viscose staple fiber is to carry out the following steps in sequence:

[0027] Cellulose pulp (cellulose dissolving pulp) → alkalization → xantholysis → dissolution → maturation → filtration to obtain spinning solution;

[0028] Spinning solution → degassing → spinning (filaments are precipitated in the coagulation bath) → stretching and cutting → first water washing → desulfurization → second water washing → bleaching → third water washing → drying → finished product storage.

[0029] The above content can be referred to, for example, patent CN201510276851.3.

[0030] The principle of the present invention is to select slightly soluble / poorly soluble carbonate particles as the raw material for the porogen. Furthermore, under certain conditions, anionic surfactants are used to self-assemble a protective layer on the surface of these inorganic carbonate particles, producing alkali-resistant and water-soluble carbonate particles. These particles are then added to the alkaline spinning solution of regenerated cellulose fibers as pore-forming agents. During spinning, a thin stream of spinning solution, embedded with the carbonate pore-forming agent, is ejected into a strongly acidic coagulation bath containing a cationic surfactant. The electrostatic attraction of the cationic surfactant desorbs the anionic surfactant protective layer on the pore-forming agent's surface. The acid then decomposes the pore-forming agent, releasing CO2 gas (carbonate decomposes in the presence of acid). Simultaneously, the fibers solidify and precipitate in the coagulation bath, forming microporous regenerated cellulose fibers. The addition of the anionic surfactant protects the carbonate particles from corrosion by the alkaline solution, while the cationic surfactant in the coagulation bath removes the protective layer on the carbonate surface. Because the fibers contain numerous micropores, they can store large amounts of liquid, resulting in excellent liquid absorption and storage properties.

[0031] The microporous regenerated cellulose fibers produced using the present invention have a porosity of 8.4% to 13.2% and a water absorption rate exceeding 132%, far exceeding the water absorption rate of regenerated cellulose fibers produced by conventional processes (approximately 105%). The high water absorption rate of regenerated cellulose fibers processed using the present invention makes them suitable for use in various nonwoven fabrics and medical hygiene products, particularly as fiber raw materials for wipes, where they exhibit significant performance advantages. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The specific embodiments of the present invention are further described in detail below with reference to the accompanying drawings.

[0033] Figure 1 This is the SEM image of the regenerated cellulose fiber prepared by the processing method in Example 1. DETAILED DESCRIPTION

[0034] The present invention is further described below with reference to specific embodiments, but the protection scope of the present invention is not limited thereto:

[0035] The present invention adds the step of "adding a pore-forming agent" to the conventional process, and adds a cationic surfactant to the coagulation bath of the spinning step. That is, the following steps are carried out in sequence:

[0036] Cellulose pulp (cellulose dissolving pulp) → alkalization → xantholysis → dissolution → maturation → filtration to obtain spinning solution;

[0037] Add pore-forming agent to the spinning solution to form a composite spinning solution → degassing → spinning (fibers are precipitated in a coagulation bath containing cationic surfactants) → stretching and cutting → first water washing → desulfurization → second water washing → bleaching → third water washing → drying → finished product storage.

[0038] In the present invention, for example, it can be specifically:

[0039] 1. The preparation method of spinning solution is specifically as follows:

[0040] Cellulose pulp (cellulose dissolving pulp) as raw material: dissolving pulp is hardwood pulp, with an α-cellulose content of 95.6% (mass%) and a degree of polymerization of 610;

[0041] Alkalization: Add the cellulose pulp raw material to a sodium hydroxide (NaOH) solution with a mass concentration of about 18% at a material-liquid ratio of 1:10 kg / L, and soak at about 42°C for 15-30 minutes (preferably 22 minutes); then squeeze to remove the alkali solution and crush to obtain alkali cellulose;

[0042] Xantholysis: Place alkali cellulose into a xantholysis reactor, introduce CS2 gas (the amount of CS2 is usually about 32% of the mass of the cellulose pulp), and react at 28°C for 1.5 hours to obtain cellulose xanthate.

[0043] Dissolution: Prepare a sodium hydroxide solution with a mass concentration of 5.0-6.5% (preferably 5.5%), and add the obtained cellulose xanthate to the sodium hydroxide solution in a volume ratio of 7.5-9.0:100 (preferably 8.2:100, i.e., 8.2%) of the mass of the cellulose pulp raw material to the sodium hydroxide solution. Stir and dissolve at 20-25°C to form a viscose solution;

[0044] Ripening: let the viscose solution stand at 10-20°C for 20-40 hours;

[0045] Filtration: Remove undissolved matter and the resulting product is named spinning solution.

[0046] 2. Add the pore-forming agent to the spinning solution according to the dosage ratio set by the present invention, and stir and disperse it evenly to form a composite spinning solution.

[0047] Degassing: Vacuum degassing to remove bubbles;

[0048] Spinning (the composite spinning solution is ejected from the spinneret into a coagulation bath containing a cationic surfactant, and the fibers are precipitated). The resulting microporous fiber strands are pulled through a guide roller and subsequently subjected to the following post-treatments:

[0049] Stretching and cutting: stretch to the required diameter and length as described in the actual process, and then cut;

[0050] First washing: The fiber is washed in 45 ℃ warm water for 10s to remove the residual coagulation bath components on the fiber;

[0051] Desulfurization: Wash the fiber with a sodium hydroxide solution at a concentration of 1.8 g / L at 75-80 °C for 30 seconds to remove residual CS2 and sulfur impurities (to prevent yellowing and odor of the fiber);

[0052] Second washing: The fiber is washed with water at pH 8-9 and 65-75°C for 10 seconds to further remove the residual sulfur on the fiber;

[0053] Bleaching: bleaching with 5 g / L sodium hypochlorite solution for 30 s to improve fiber whiteness;

[0054] Three washes: Use a pH 5-6 citric acid solution to remove chemical residues such as bleach;

[0055] Drying: Dry to a moisture content of about 10%-12%, then roll or pack into shape

[0056] The viscose fibers produced in the following examples all had a diameter of approximately 13.8 μm (using a 70 μm spinneret) and a length of 32 mm. The control fibers described below were produced using a conventional spinning process without the addition of a pore-forming agent or surfactant to the spinning bath.

[0057] The particle size of the granular inorganic carbonate used in the present invention is 0.5-3 μm.

[0058] Example 1: A method for preparing highly water-absorbent microporous regenerated cellulose fiber, comprising the following steps:

[0059] 1) Preparation of pore-forming agent:

[0060] 100 g of magnesium carbonate particles and 0.3 g of sodium dodecylbenzenesulfonate were added to 180 mL of 95% ethanol. At this time, the magnesium carbonate particles were completely immersed. The mixture was immersed and compounded at 8 ° C for 8 min (so that the sodium dodecylbenzenesulfonate was adsorbed on the magnesium carbonate particles), and then filtered. The filtered solid was named an alkali-resistant pore-forming agent.

[0061] 2) Preparation of composite spinning solution:

[0062] First, according to the conventional spinning solution processing method mentioned above, a spinning solution is prepared from cellulose pulp;

[0063] The pore-forming agent was added to a spinning solution prepared from the cellulose pulp at a weight ratio of 100:3.5, the mixture was stirred and mixed uniformly, and then degassed (vacuum degassing to remove bubbles) to prepare a composite spinning solution.

[0064] 3) Add 2 g / L of dodecyltrimethylammonium chloride (2 g of dodecyltrimethylammonium chloride is added to each liter of coagulation bath) to a coagulation bath (containing 115 g / L of H2SO4, 160 g / L of Na2SO4, and 15 g / L of ZnSO4, the same below) to obtain a coagulation bath containing a cationic surfactant;

[0065] The composite spinning solution is extruded from the spinneret into a coagulation bath containing a cationic surfactant at a bath temperature of 50°C, and precipitated in the coagulation bath to obtain microporous fiber filaments.

[0066] Note: The diameter of the spinneret is only related to the thickness of the fiber.

[0067] 4) The obtained microporous fiber strands are drawn through a guide wire roller and subjected to the following post-treatments in sequence to obtain a finished product of highly absorbent microporous regenerated cellulose fiber;

[0068] The post-processing is as follows: stretching, cutting → first water washing → desulfurization → second water washing → bleaching → third water washing → drying → finished product storage.

[0069] The finished product of highly absorbent microporous regenerated cellulose fiber has a diameter of about 13.8 μm and a length of 32 mm.

[0070] The SEM image of the regenerated cellulose fiber obtained in Example 1 is as follows: Figure 1 As shown, the fiber contains a large number of micropores. Mercury porosimetry tests show that the average pore size of the fiber's micropores is approximately 0.57 μm.

[0071] Control fiber:

[0072] The pore-forming agent in Example 1 was omitted, and no surfactant was added to the spinning coagulation bath. The rest was the same as in Example 1. The obtained fibers were control fibers, i.e., fibers prepared by conventional spinning process.

[0073] Example 2: A method for preparing highly water-absorbent microporous regenerated cellulose fibers:

[0074] 1) Preparation of pore-forming agent:

[0075] 100 g of zinc carbonate particles and 0.5 g of sodium hexadecyl sulfate were added to 150 mL of 95% ethanol. At this time, the zinc carbonate particles were completely immersed. The mixture was immersed and compounded at 5 ° C for 10 min (so that the sodium hexadecyl sulfate was adsorbed on the zinc carbonate particles), and then filtered. The filtered solid was named an alkali-resistant pore-forming agent.

[0076] Step 2) ~ Step 4):

[0077] The weight ratio of cellulose pulp: pore-forming agent was changed from "100: 3.5" to "100: 5";

[0078] 4 g / L of octadecyltrimethylammonium chloride was added to the coagulation bath to obtain a coagulation bath containing a cationic surfactant;

[0079] The rest is the same as step 2) to step 4) of Example 1.

[0080] Example 3: A method for preparing highly water-absorbent microporous regenerated cellulose fibers:

[0081] 1) Preparation of pore-forming agent:

[0082] 100 g of zinc carbonate particles and 0.5 g of sodium octadecyl sulfate were added to 150 mL of 95% ethanol. At this time, the zinc carbonate particles were completely immersed. The mixture was immersed and compounded at 1 ° C for 20 min (so that the sodium octadecyl sulfate was adsorbed on the zinc carbonate particles), and then filtered. The solid obtained by filtration was named an alkali-resistant pore-forming agent.

[0083] Step 2) ~ Step 4):

[0084] The weight ratio of cellulose pulp: pore-forming agent was changed from "100:3.5" to "100:12";

[0085] 4 g / L of octadecyltrimethylammonium chloride was added to the coagulation bath to obtain a coagulation bath containing a cationic surfactant;

[0086] The rest is the same as step 2) to step 4) of Example 1.

[0087] Example 4: A method for preparing highly water-absorbent microporous regenerated cellulose fibers:

[0088] 1) Preparation of pore-forming agent:

[0089] 100 g of barium carbonate particles and 0.8 g of sodium octadecyl sulfate were added to 180 mL of 95% ethanol. At this time, the barium carbonate particles were completely immersed. The mixture was immersed and compounded at 8 ° C for 25 min (so that the sodium octadecyl sulfate was adsorbed on the barium carbonate particles), and then filtered. The solid obtained by filtration was named an alkali-resistant pore-forming agent.

[0090] Step 2) ~ Step 4):

[0091] The weight ratio of cellulose pulp: pore-forming agent was changed from "100:3.5" to "100:12";

[0092] Add 2 g / L of dodecyltrimethylammonium chloride to the coagulation bath to obtain a coagulation bath containing a cationic surfactant;

[0093] The rest is the same as step 2) to step 4) of Example 1.

[0094] The highly water-absorbent microporous regenerated cellulose fibers obtained in Examples 1 to 4 were subjected to the following performance tests:

[0095] Fiber water absorption test: Take about 10g of fiber and immerse it in deionized water to completely wet the fiber. Then take out the fiber and place it in a spin dryer. Dehydrate it at 1000 r / min for 3 minutes. Then take it out and quickly weigh the wet weight of the fiber m1. Then heat the wet fiber at 110℃ for 30 minutes. Then take out the fiber and equilibrate it under standard atmospheric conditions in a constant temperature and humidity chamber for 12 hours. The standard weight of the fiber is m0. The fiber water absorption (%) = (m1-m0) / m0×100%.

[0096] The fiber porosity was measured according to the method described in Wang Yanpeng, Miao Qingxian. Measurement of fiber porosity and cellulose content measured by density method, Heilongjiang Papermaking, 2009, 1: 12-13.

[0097] Fiber strength test: Test the fiber strength in a constant temperature and humidity room under standard atmospheric conditions according to GB / T 14337-2008 Chemical Fibers. Test Method for Tensile Properties of Staple Fibers.

[0098] The test results are as follows:

[0099] The porosity test results of the fibers obtained in Examples 1-4 are shown in Table 1. As can be seen, the porosity of the fibers obtained in all Examples increased significantly compared to the control. In particular, Example 3 achieved a porosity as high as 13.24%, indicating that this fiber possesses improved water absorption properties.

[0100] The fiber water absorption and strength test results are shown in Table 1. Compared to fibers obtained without the addition of a pore-forming agent (control sample, water absorption rate of 105.3%), the microporous fibers obtained in Examples achieved a water absorption rate exceeding 132%. In particular, the fibers obtained in Example 3 achieved a water absorption rate of 168.3%. This demonstrates the significant effectiveness of the present method.

[0101] Although the strength of the fibers obtained in all examples was reduced due to the presence of micropores, regenerated cellulose fibers with a strength greater than 1.4 cN / dtex are acceptable as fiber materials for nonwoven fabrics.

[0102] Table 1 Properties of the fibers obtained in various examples of this experiment

[0103]

[0104] Comparative Example 1: The zinc carbonate in Example 3 was replaced with sodium bicarbonate (the amount remained unchanged), and the solvent was changed to anhydrous ethanol (the volume remained unchanged); other parameters remained unchanged, and the properties of the obtained fiber were shown in Table 2.

[0105] The resulting fiber had a porosity and water absorption rate of only 4.06% and 122.7%, respectively. This is because sodium bicarbonate is highly water-soluble, and its particles dissolve rapidly in the spinning solution. When the spinning jet enters the coagulation bath, it is unable to decompose into larger particles within the fiber to form larger micropores. This indicates that using inorganic carbonates other than those specified in this invention does not yield good water absorption properties.

[0106] Comparative Example 2: The barium carbonate in Example 4 was replaced by sodium carbonate (the amount remained unchanged), and the solvent was changed to anhydrous ethanol (the volume remained unchanged); other parameters remained unchanged, and the properties of the obtained fiber were shown in Table 2.

[0107] The resulting fiber had a water absorption rate of only 118.5%. This is because sodium carbonate is highly water-soluble, and the sodium carbonate particles dissolve rapidly in the spinning solution. Once the spinning jet enters the coagulation bath, the sodium carbonate cannot remain in particle form and decompose, thus failing to form large micropores in the fiber and achieve good water absorption. This indicates that using inorganic carbonates other than those specified in this invention cannot achieve good water absorption.

[0108] Comparative Example 3: The surfactant (sodium octadecylsulfonate) in Example 3 was replaced with sodium 1-heptanesulfonate (its C n The n value of the alkyl group is 6), and other parameters remain unchanged. The properties of the obtained fiber are shown in Table 2.

[0109] The water absorption rate of the obtained fiber is only 127.8%. This is because the carbon chain of the surfactant is too short and its hydrophobicity is limited, which cannot effectively form a protective layer on the surface of the carbonate particles. As a result, the carbonate particles dissolve in the spinning solution, making it difficult for the fiber to form larger micropores, resulting in limited water absorption performance of the fiber.

[0110] Comparative Example 4: The mass ratio of zinc carbonate to sodium octadecyl sulfate in Example 3 was replaced from 100:0.5 to 100:0.1, with other parameters remaining unchanged. The properties of the obtained fiber are shown in Table 2. The water absorption rate of the obtained fiber was only 129.2%.

[0111] Comparative Example 5: The temperature for compounding zinc carbonate and sodium octadecyl sulfate in 95% ethanol in Example 3 was changed to 20°C, and other parameters remained unchanged. The properties of the obtained fiber are shown in Table 2.

[0112] The water absorption rate of the obtained fiber was only 135.0%, which was significantly lower than that of the fiber obtained in Example 3. This was because the solubility of carbonate in 95% ethanol increased with increasing temperature.

[0113] Comparative Example 6: The compounding time of zinc carbonate and sodium octadecyl sulfate in 95% ethanol in Example 3 was replaced with 3 min, and other parameters remained unchanged. The properties of the obtained fiber are shown in Table 2.

[0114] The water absorption rate of the obtained fiber was only 131.3%, which was significantly lower than that of the fiber obtained in Example 3. This was because the compounding time was too short, making it difficult for the surfactant to form an effective protective layer on the surface of the carbonate particles.

[0115] Comparative Example 7: The weight ratio of cellulose pulp: pore-forming agent in Example 3 was replaced with 100:1, and other parameters remained unchanged. The properties of the obtained fiber are shown in Table 2.

[0116] The water absorption rate of the obtained fiber was only 110.2%, which was significantly lower than that of the fiber obtained in Example 3. This is because the low content of the pore-forming agent made it difficult to form a large number of micropores in the fiber, and thus the water absorption rate of the fiber was limited.

[0117] Comparative Example 8: The weight ratio of cellulose pulp: pore-forming agent in Example 3 was replaced with 100:20, and other parameters remained unchanged. The properties of the obtained fiber are shown in Table 2.

[0118] The resulting fiber's water absorption rate significantly increased to 182.0%, but the fiber's strength dropped significantly, to only 1.09 cN / dtex. This was due to the excessive porosity (18.41%), which significantly affected the fiber's structure. This made it difficult to meet the fiber strength requirements (above 1.30 cN / dtex) for nonwoven fabric processing and product use. This was because the excessive pore-forming agent content created excessive micropores in the fiber, significantly affecting the fiber's structure and mechanical properties.

[0119] Table 2 Properties of the fibers obtained in each comparative example in this experiment

[0120]

[0121] Finally, it should be noted that the above examples are merely specific embodiments of the present invention. Obviously, the present invention is not limited to the above examples and is subject to numerous variations. All variations that can be directly derived or conceived by a person of ordinary skill in the art from the disclosure of the present invention are considered to be within the scope of protection of the present invention.

Claims

1. A pore-forming agent, characterized in that: The preparation method of the pore-forming agent used for preparing highly absorbent microporous regenerated cellulose fibers is as follows: The inorganic carbonate is immersed in a solvent, an anionic surfactant is added, and the mixture is immersed at 0-10 °C for 5-30 minutes, followed by solid-liquid separation. The obtained solid is a pore-forming agent. The mass ratio of the inorganic carbonate to the anionic surfactant is 100: 0.2-1.0; Inorganic carbonates are magnesium carbonate, zinc carbonate, and barium carbonate; The solvent is ethanol with a volume concentration of 90-95%; The anionic surfactant is a Cn alkyl anionic surfactant, and the carbon chain length satisfies n≥12.

2. The pore-forming agent according to claim 1, characterized in that: The anionic surfactant is at least any one of the following: sodium dodecylbenzenesulfonate, sodium hexadecyl sulfate, and sodium octadecylsulfonate.

3. The pore-forming agent according to claim 2, characterized in that: Weight of inorganic carbonate g: volume of solvent ml≤1.

4. A method for preparing highly absorbent microporous regenerated cellulose fibers, comprising preparing a spinning solution from cellulose pulp, ejecting the solution from a spinneret, and precipitating the solution in a coagulation bath to obtain fiber strands; characterized in that: Using the pore-forming agent according to any one of claims 1 to 3, comprising the following steps: 1) Preparation of composite spinning solution: Adding the pore-forming agent to a spinning solution prepared from cellulose pulp at a weight ratio of cellulose pulp to pore-forming agent = 100: 2-15, stirring and mixing the mixture evenly, and then degassing the mixture to obtain a composite spinning solution; 2) In the spinning step: add 1-5 g of a cationic surfactant per liter of the coagulation bath to obtain a coagulation bath containing a cationic surfactant; The composite spinning solution is extruded from a spinneret into a coagulation bath containing a cationic surfactant, and precipitated in the coagulation bath to obtain microporous fiber strands; 3) The microporous fiber strips are post-treated to obtain highly water-absorbent microporous regenerated cellulose fibers.

5. The method for preparing highly water-absorbent microporous regenerated cellulose fiber according to claim 4, characterized in that: The cationic surfactant is a Cn alkyl cationic surfactant, and the carbon chain length satisfies n≥1.

6. The method for preparing highly water-absorbent microporous regenerated cellulose fiber according to claim 5, characterized in that: The cationic surfactant is at least any one of the following: dodecyltrimethylammonium chloride and octadecyltrimethylammonium bromide.

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