Preparation method of high-water-absorption microporous regenerated cellulose fiber

Abstract

The invention belongs to the field of regenerated cellulose fiber manufacturing, and particularly discloses a pore-forming agent for preparing high-water-absorption microporous regenerated cellulose fibers, and a preparation method of the pore-forming agent comprises the following steps: immersing inorganic carbonate in a solvent, adding an anionic surfactant, impregnating and compounding at 0-10 DEG C for 5-30 minutes, and then carrying out solid-liquid separation to obtain a solid which is the pore-forming agent. The invention also discloses a preparation method of the high-water-absorption microporous regenerated cellulose fiber, which comprises the following steps: adding a pore-forming agent into a spinning solution prepared from cellulose pulp, uniformly stirring and mixing, and defoaming to prepare a composite spinning solution; extruding the composite spinning solution from a spinneret orifice, enabling the composite spinning solution to enter a coagulating bath containing a cationic surface active agent, and separating out the composite spinning solution in the coagulating bath to obtain microporous fiber filaments; and carrying out post-treatment on the microporous fiber filaments to obtain the high-water-absorption microporous regenerated cellulose.

Description

Technical Field

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

[0002] Viscose fiber is a kind of regenerated cellulose fiber, which is made from natural cellulose (such as wood, cotton linter) as raw material through chemical treatment and spinning. Its preparation process mainly includes raw material preparation of cellulose pulp (dissolving pulp), alkalization, xanthation, dissolution, aging, filtration. The obtained spinning dope is degassed and then ejected from the spinneret holes and precipitated into filaments in the coagulation bath, and the filaments are subjected to corresponding post-treatment and other steps. The obtained fibers have almost no micropores.

[0003] Due to its excellent hygroscopicity and biocompatibility, viscose fiber has become one of the core materials for medical and health products. Because of its raw material cost advantage, good skin-friendly property and degradable characteristics, viscose fiber has gradually replaced cotton fiber and has been widely used in personal hygiene textiles (such as facial soft towels, facial cleansing towels, cotton pads, sanitary napkins, adult incontinence care pads, etc.), medical textiles (gauze and wound dressings), etc.; the demand for fiber materials with high liquid absorption (including water absorption, blood absorption) performance in these applications is increasing day by day. However, the dense cortical layer on the surface of conventional viscose fibers hinders the rapid penetration of liquid, and its water absorption capacity is limited. Therefore, the development of highly absorbent viscose fibers has broad application prospects.

[0004] In order to improve the water absorption performance of viscose fiber non-woven products, the industry realizes it through methods such as fiber modification, blending or post-treatment. For example, Patent CN202411787984.2 improves the hydrophilicity of viscose fiber by carboxymethylating cellulose, but directly chemically modifying the molecular structure of the fiber will inevitably affect the physical and chemical properties of the fiber and cause chemical residues; the literature (Nonwovens. 2009, 17 (4): 20-23.) reports a method for processing highly absorbent non-woven fabrics by blending ordinary viscose fibers with highly absorbent fibers. Although this technology significantly improves the liquid absorption capacity of viscose fiber non-woven products, due to the introduction of synthetic polymers, the product has disadvantages in terms of environmental degradability. Patent CN202410879367.9 reports a method for producing highly absorbent non-woven products by compounding high molecular water-absorbing resin with fibers. This method belongs to the post-treatment method, which increases the processing procedures and raw material use of viscose non-woven fabrics and increases the production cost. If highly absorbent fibers can be directly processed during the viscose fiber processing stage, it will not only have low cost, but also contribute to industrial energy conservation and carbon reduction, and is expected to become a key development direction to break through the existing technical barriers. Summary of the Invention

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

[0006] 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: Immerse inorganic carbonate (granular) in a solvent (the solvent completely immerses the inorganic carbonate particles), add an anionic surfactant, and then impregnate and compound at 0 - 10 °C (compound under static conditions) for 5 - 30 min (preferably 8 - 20 min at 1 - 8 °C), and then perform solid-liquid separation (filtration). The obtained solid is the pore-forming agent (an alkali-resistant pore-forming agent); The mass ratio of the inorganic carbonate particles to the anionic surfactant is 100:0.2 - 1.0 (preferably 100:0.3 - 0.8).

[0007] As an improvement to the pore-forming agent of the present invention: The inorganic carbonate is magnesium carbonate, zinc carbonate, or barium carbonate; The solvent is ethanol with a volume concentration of 90 - 95%; The anionic surfactant is a C n alkyl anionic surfactant with a carbon chain length satisfying n≥12.

[0008] As a further improvement to the pore-forming agent of the present invention: The anionic surfactant is at least any one of the following: sodium dodecylbenzenesulfonate, sodium hexadecyl sulfate, and sodium octadecyl sulfonate.

[0009] As a further improvement to the pore-forming agent of the present invention: The weight (g) of the inorganic carbonate: the volume (ml) of the solvent ≤ 1. For example, it is 100 g:150 - 180 ml.

[0010] The present invention also simultaneously provides a method for preparing highly absorbent microporous regenerated cellulose fibers, including preparing a spinning solution (a composite spinning solution in the present invention) from cellulose pulp (cellulose dissolving pulp), and then ejecting it from a spinneret hole and precipitating it in a coagulation bath to obtain fiber filaments (microporous fiber filaments in the present invention); using the above pore-forming agent, and successively performing the following steps: 1) Preparation of the composite spinning solution: According to the weight ratio of cellulose pulp:pore-forming agent = 100:2 - 15 (preferably 100:3.5 - 12), add the pore-forming agent to the spinning solution (the spinning dope of the prior art) prepared from cellulose pulp, stir and mix evenly, and then defoam (perform vacuum defoaming to remove air bubbles) to obtain a composite spinning solution; 2) In the spinning step: add 1 - 5 g of a cationic surfactant to each liter of the coagulation bath (that is, add a cationic surfactant with a mass concentration of 1 - 5 g / L, preferably 2 - 4 g / L) to obtain a coagulation bath containing a cationic surfactant; The composite spinning solution is extruded from a spinneret hole (with a pore diameter of 50 - 120 μm) into a coagulation bath containing a cationic surfactant, and precipitates in the coagulation bath to obtain a microporous fiber filament. Note: The coagulation bath is H2SO4 115 ± 5 g / L, Na2SO4 160 ± 5 g / L, ZnSO4 15 ± 5 g / L; the bath temperature is 50 ± 5 °C.

[0011] 3) The microporous fiber filament is post-treated to obtain a highly absorbent microporous regenerated cellulose fiber.

[0012] As an improvement to the preparation method of the highly absorbent microporous regenerated cellulose fiber of the present invention: the cationic surfactant is a C n alkyl cationic surfactant, and the carbon chain length satisfies n ≥ 1.

[0013] As a further improvement to the preparation method of the highly absorbent microporous regenerated cellulose fiber of the present invention: the cationic surfactant is at least any one of the following: dodecyl trimethyl ammonium chloride, octadecyl trimethyl ammonium bromide.

[0014] The conventional production process of viscose staple fiber is to sequentially perform the following steps: Cellulose pulp (cellulose dissolving pulp) → alkalization → xanthation → dissolution → ripening → filtration to obtain a spinning dope; Spinning dope → degassing → spinning (precipitating filaments in a coagulation bath) → stretching, cutting → first water washing → desulfurization → second water washing → bleaching → third water washing → drying → finished product warehousing.

[0015] The above content can be referred to, for example, in Patent CN201510276851.3.

[0016] The principle of the present invention is as follows: Carbonate particles that are slightly soluble or insoluble in water are selected as the raw material of the pore-forming agent. Further, under certain conditions, an anionic surfactant is self-assembled on the surface of such inorganic carbonate particles to form a protective layer, and carbonate particles that are alkali-resistant and water-insoluble are prepared. As a pore-forming agent, it is added to the spinning solution of alkaline regenerated cellulose fibers. During spinning, the spinning solution stream embedded with the carbonate pore-forming agent is ejected into a strongly acidic coagulation bath containing a cationic surfactant. Under the electrostatic attraction of the cationic surfactant, the anionic surfactant protective layer on the surface of the pore-forming agent is desorbed, and the acid solution decomposes the pore-forming agent without the protective layer. The pore-forming agent decomposes to produce CO2 gas (carbonate decomposes to produce CO2 gas when encountering acid), and at the same time, the fiber solidifies and precipitates in the coagulation bath to form microporous regenerated cellulose fibers. Among them, the addition of the anionic surfactant plays a role in wrapping and protecting the carbonate particles from being corroded by the alkali solution, while the cationic surfactant in the coagulation bath plays a role in removing the protective layer on the surface of the carbonate. Since the fiber contains a large number of micropores and can store a large amount of liquid, the fiber has excellent liquid absorption and liquid storage properties.

[0017] Through the technical method of the present invention, the porosity of the microporous regenerated cellulose fibers prepared is as high as 8.4% - 13.2%, and the water absorption rate reaches more than 132%, far exceeding the water absorption rate (about 105%) of the regenerated cellulose fibers produced by the conventional process. The regenerated cellulose fibers processed by the method of the present invention have a high water absorption rate and are suitable for various non-woven fabrics and medical and hygienic material fields, especially as the fiber raw material for wiping products, and have significant performance advantages. Description of the Drawings

[0018] The following further elaborates on the specific implementation manners of the present invention in conjunction with the drawings.

[0019] Figure 1 SEM diagram of the regenerated cellulose fibers prepared by the processing method of Example 1. Specific Implementation Manner

[0020] The following further describes the present invention in conjunction with specific embodiments, but the protection scope of the present invention is not limited thereto: The present invention adds the process of "adding a pore-forming agent" on the basis of the conventional process, and a cationic surfactant is added to the coagulation bath in the spinning step. That is, the following steps are carried out in sequence: Cellulose pulp (cellulose dissolving pulp) → alkalization → xanthation → dissolution → aging → filtration to obtain a spinning dope; Adding a pore-forming agent to the spinning dope to form a composite spinning solution → degassing → spinning (the fiber precipitates in a coagulation bath containing a cationic surfactant) → stretching, cutting → first water washing → desulfurization → second water washing → bleaching → third water washing → drying → finished product warehousing.

[0021] In the present invention, for example, it can be specifically: 1. The preparation method of spinning solution is specifically as follows: 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; Alkalization: adding the cellulose pulp raw material into a sodium hydroxide (NaOH) solution with a mass concentration of about 18% at a material-liquid ratio of 1:10 kg / L, and soaking it at about 42°C for 15-30 min (preferably 22 min); then squeezing to remove the alkali solution and crushing to obtain alkali cellulose; Xantholysis: put alkali cellulose into a xantholysis reactor, introduce CS2 gas (CS2 dosage is usually about 32% of the mass of cellulose pulp), react at 28°C for 1.5 h to obtain cellulose xanthate; Dissolving: preparing a sodium hydroxide solution with a mass concentration of 5.0-6.5% (preferably 5.5%), adding the obtained cellulose xanthate to the sodium hydroxide solution according to a volume ratio of the mass of the cellulose pulp raw material to the sodium hydroxide solution of 7.5-9.0: 100 (preferably 8.2: 100, i.e. 8.2%), stirring and dissolving at 20-25° C. to form a viscose solution; Ripening: The viscose solution is allowed to stand at 10-20°C for 20-40 hours; Filtration: Remove the undissolved matter and the resulting substance is named spinning solution.

[0022] 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.

[0023] Degassing: Vacuum degassing to remove bubbles; 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 by a guide roller and then subjected to the following post-treatments: Stretching and cutting: After stretching to the required diameter and length as described in practice, cut; First washing: The fiber is washed in 45 ℃ warm water for 10 seconds to remove the residual coagulation bath components on the fiber; Desulfurization: Wash the fiber with 1.8g / L sodium hydroxide solution at 75-80℃ for 30s to remove residual CS2 and sulfur impurities (to prevent yellowing and odor of the fiber); Second washing: The fiber is washed with water at pH 8-9 and 65-75 ℃ for 10 s to further remove the residual sulfur on the fiber; Bleaching: bleaching with 5 g / L sodium hypochlorite solution for 30 s to improve fiber whiteness; Three washes: Use a pH 5-6 citric acid solution to remove chemical residues such as bleach; Drying: Dry to a moisture content of about 10%-12%, and then wind or pack and form. The specifications of the viscose fibers prepared in the following cases are all: about 13.8 μm in diameter (the aperture of the spinneret used is 70 μm), and 32 mm in length. Among them, the control sample fibers described below are: fibers prepared by the conventional spinning process without adding pore-forming agent and without adding surfactant in the spinning coagulation bath.

[0024] The particle size of the granular inorganic carbonate used in the present invention is 0.5-3 μm.

[0025] Example 1. A preparation method of a highly water-absorbent microporous regenerated cellulose fiber, which successively performs the following steps: 1). Preparation of pore-forming agent: Add 100 g of magnesium carbonate particles and 0.3 g of sodium dodecylbenzenesulfonate to 180 mL of 95% ethanol. At this time, the magnesium carbonate particles are completely immersed, and impregnate and compound for 8 min at 8 °C (so that sodium dodecylbenzenesulfonate is adsorbed on the magnesium carbonate particles), and then filter. The obtained solid is named an alkali-resistant pore-forming agent.

[0026] 2). Preparation of composite spinning solution: First, according to the above-mentioned conventional spinning solution processing method, use cellulose pulp to prepare a spinning dope; According to the weight ratio of cellulose pulp as raw material: pore-forming agent = 100: 3.5, add the pore-forming agent to the spinning dope prepared from cellulose pulp, stir and mix evenly, and then defoam (vacuum defoaming to remove air bubbles) to obtain a composite spinning solution; 3). Add 2 g / L of dodecyltrimethylammonium chloride (add 2 g of dodecyltrimethylammonium chloride per liter of coagulation bath) to the coagulation bath (containing 115 g / L of H2SO4, 160 g / L of Na2SO4, 15 g / L of ZnSO4, the same below) to obtain a coagulation bath containing a cationic surfactant; Extrude the composite spinning solution from the spinneret into the coagulation bath containing a cationic surfactant, with the bath temperature of 50 °C, and precipitate in the coagulation bath to obtain microporous fiber filaments.

[0027] Note: The diameter of the spinneret is only related to the thickness of the fiber.

[0028] 4). The obtained microporous fiber filaments are successively subjected to the following post-treatments through a godet roller to obtain a finished product of highly water-absorbent microporous regenerated cellulose fiber; The post-treatment is: stretching, cutting → first water washing → desulfurization → second water washing → bleaching → third water washing → drying → finished product warehousing.

[0029] The diameter of the finished product of the highly absorbent microporous regenerated cellulose fiber is about 13.8 μm, and the length is 32 mm.

[0030] The SEM image of the regenerated cellulose fiber obtained in Example 1 is as Figure 1 shown. The fiber contains a large number of micropores. It is known from the mercury intrusion porosimetry test that the average pore diameter of the micropores of this fiber is about 0.57 μm.

[0031] Control sample fiber: The use of the pore-forming agent in Example 1 was cancelled, and no surfactant was added to the spinning coagulation bath. The rest was the same as in Example 1. The obtained fiber was the control sample fiber, that is, the fiber prepared by the conventional spinning process.

[0032] Example 2. A preparation method of a highly absorbent microporous regenerated cellulose fiber: 1) Preparation of the pore-forming agent: 100 g of zinc carbonate particles and 0.5 g of sodium dodecyl sulfate were added to 150 mL of 95% ethanol. At this time, the zinc carbonate particles were completely immersed. They were impregnated and compounded at 5 °C for 10 min (so that sodium dodecyl sulfate was adsorbed on the zinc carbonate particles), and then filtered. The obtained solid was named the alkali-resistant pore-forming agent.

[0033] Steps 2) to 4): The weight ratio of cellulose pulp to pore-forming agent was changed from "100: 3.5" to "100: 5"; 4 g / L of octadecyltrimethylammonium chloride was added to the coagulation bath to obtain a coagulation bath containing a cationic surfactant; The rest was the same as Steps 2) to 4) of Example 1.

[0034] Example 3. A preparation method of a highly absorbent microporous regenerated cellulose fiber: 1) Preparation of the pore-forming agent: 100 g of zinc carbonate particles and 0.5 g of sodium octadecyl sulfonate were added to 150 mL of 95% ethanol. At this time, the zinc carbonate particles were completely immersed. They were impregnated and compounded at 1 °C for 20 min (so that sodium octadecyl sulfonate was adsorbed on the zinc carbonate particles), and then filtered. The obtained solid was named the alkali-resistant pore-forming agent.

[0035] Steps 2) to 4): The weight ratio of cellulose pulp to pore-forming agent was changed from "100: 3.5" to "100: 12"; 4 g / L of octadecyltrimethylammonium chloride was added to the coagulation bath to obtain a coagulation bath containing a cationic surfactant; The rest was the same as Steps 2) to 4) of Example 1.

[0036] Example 4. A method for preparing highly water-absorbent microporous regenerated cellulose fibers: 1). Preparation of pore-forming agent: Add 100 g of barium carbonate particles and 0.8 g of sodium octadecyl sulfonate to 180 mL of 95% ethanol. At this time, the barium carbonate particles are completely immersed. Impregnate and compound for 25 min at 8 °C (so that sodium octadecyl sulfonate is adsorbed on the barium carbonate particles), and then filter. The solid obtained by filtration is named an alkali-resistant pore-forming agent.

[0037] Steps 2) to 4): Change the weight ratio of cellulose pulp to pore-forming agent from "100: 3.5" to "100: 12"; Add 2 g / L of dodecyl trimethyl ammonium chloride to the coagulation bath to obtain a coagulation bath containing a cationic surfactant; The rest is the same as Steps 2) to 4) of Example 1.

[0038] Perform the following performance tests on the highly water-absorbent microporous regenerated cellulose fibers obtained in Examples 1 to 4: Fiber water absorption rate test: Take about 10 g of fibers and immerse them in deionized water to completely wet the fibers. Then take out the fibers and place them in a centrifugal dryer, dehydrate for 3 min at 1000 r / min. Then take out and quickly weigh the wet weight m1 of the fibers. Then heat-dry the wet fibers at 110 °C for 30 min, and then take out the fibers and balance them in a standard atmosphere in a constant temperature and humidity chamber for 12 h to obtain the standard weight m0 of the fibers. Then the water absorption rate (%) of the fibers = (m1 - m0) / m0 × 100%.

[0039] The test method for fiber porosity is carried out according to the method described in "Wang Yanpeng, Miao Qingxian. Measurement of fiber porosity and cellulose content measured by density method, Heilongjiang Paper Making, 2009, 1: 12 - 13".

[0040] Fiber strength test: Test the strength of the fibers in a standard atmosphere in a constant temperature and humidity chamber according to "GB / T 14337 - 2008 Chemical Fibers. Test Method for Tensile Properties of Staple Fibers".

[0041] The test results are as follows: The test results of the fiber porosity of the fibers obtained in Examples 1 to 4 are shown in Table 1. It can be seen that, compared with the control sample, the fiber porosity of all the fibers obtained in the examples has increased significantly. Especially in Example 3, the fiber porosity is as high as 13.24%, indicating that the fiber has better water absorption performance.

[0042] The test results of the water absorption rate and strength of the fibers are shown in Table 1. Compared with the fibers obtained without adding pore-forming agent (control sample, water absorption rate is 105.3%), the water absorption rate of the microporous fibers obtained in the examples has increased to more than 132%. In particular, for the fibers obtained in Example 3, the water absorption rate reached 168.3%. It can be seen that the method of the present invention has remarkable effects.

[0043] Although due to the presence of micropores, the strength of the fibers obtained in all examples has decreased, however, as a fiber material for non-woven fabrics, regenerated cellulose fibers with a strength greater than 1.4 cN / dtex are acceptable.

[0044] Table 1 Properties of the fibers obtained in each example in this test

[0045] Comparative Example 1: Replace the zinc carbonate in Example 3 with sodium bicarbonate (the dosage remains unchanged), and change the solvent to anhydrous ethanol (the volume remains unchanged); other parameters remain unchanged, and the properties of the obtained fibers are shown in Table 2.

[0046] The porosity and water absorption rate of the obtained fibers are only 4.06% and 122.7% respectively. This is because the water solubility of sodium bicarbonate is very high, and the sodium bicarbonate particles dissolve rapidly in the spinning solution. When the spinning jet enters the coagulation bath, it cannot decompose in the fiber in the form of larger particles to form larger micropores. It can be seen that using inorganic carbonates other than those specified in the present invention cannot obtain good water absorption performance.

[0047] Comparative Example 2: Replace the barium carbonate in Example 4 with sodium carbonate (the dosage remains unchanged), and change the solvent to anhydrous ethanol (the volume remains unchanged); other parameters remain unchanged, and the properties of the obtained fibers are shown in Table 2.

[0048] The water absorption rate of the obtained fibers is only 118.5%. This is because the water solubility of sodium carbonate is very high, and the sodium carbonate particles dissolve rapidly in the spinning solution. When the spinning jet enters the coagulation bath, sodium carbonate cannot exist and decompose in the form of particles, so it cannot form larger micropores in the fiber to obtain good water absorption performance. It can be seen that using inorganic carbonates other than those specified in the present invention cannot obtain good water absorption performance.

[0049] Comparative Example 3: Replace the surfactant (sodium octadecylsulfonate) in Example 3 with sodium 1-heptanesulfonate (the n value of its C n alkyl is 6), other parameters remain unchanged, and the properties of the obtained fibers are shown in Table 2.

[0050] The water absorption rate of the obtained fibers is only 127.8%. This is because the carbon chain of the surfactant is too short and the hydrophobicity is limited, so it cannot effectively form a protective layer on the surface of the carbonate particles, resulting in the dissolution of the carbonate particles in the spinning solution, making it difficult to form larger micropores in the fibers, thus resulting in limited water absorption performance of the fibers.

[0051] Comparative Example 4: Replace the mass percentage of zinc carbonate to sodium octadecylsulfonate in Example 3 from 100:0.5 to 100:0.1, with other parameters unchanged. The properties of the obtained fibers are shown in Table 2. The water absorption rate of the obtained fibers is only 129.2%.

[0052] Comparative Example 5: Replace the temperature of the compounding of zinc carbonate and sodium octadecylsulfonate in 95% ethanol in Example 3 with 20 °C, with other parameters unchanged. The properties of the obtained fibers are shown in Table 2.

[0053] The water absorption rate of the obtained fibers is only 135.0%. Comparing with the fibers obtained in Example 3, its water absorption performance has decreased significantly. This is because as the temperature increases, the solubility of carbonate in 95% ethanol will increase and other reasons.

[0054] Comparative Example 6: Replace the compounding time of zinc carbonate and sodium octadecylsulfonate in 95% ethanol in Example 3 with 3 min, with other parameters unchanged. The properties of the obtained fibers are shown in Table 2.

[0055] The water absorption rate of the obtained fibers is only 131.3%. Comparing with the fibers obtained in Example 3, its water absorption performance has decreased significantly. This is because the compounding time is too short, and it is difficult for the surfactant to form an effective protective layer on the surface of carbonate particles.

[0056] Comparative Example 7: Replace the weight ratio of cellulose pulp to pore former in Example 3 with 100:1, with other parameters unchanged. The properties of the obtained fibers are shown in Table 2.

[0057] The water absorption rate of the obtained fibers is only 110.2%. Comparing with the fibers obtained in Example 3, its water absorption performance has decreased significantly. This is because the content of pore former is small, and it is difficult to form a large number of micropores in the fibers. Therefore, the improvement of the water absorption rate of the fibers is limited.

[0058] Comparative Example 8: Replace the weight ratio of cellulose pulp to pore former in Example 3 with 100:20, with other parameters unchanged. The properties of the obtained fibers are shown in Table 2.

[0059] The water absorption rate of the obtained fibers has increased significantly to 182.0%, but the strength of the fibers has decreased very significantly, only 1.09 cN / dtex. This is due to the excessive porosity (18.41%), which significantly affects the structure of the fiber body. It is difficult to meet the requirements for the fiber strength in non-woven processing and product use (above 1.30 cN / dtex). This is because the content of pore former is too high, forming excessive micropores in the fibers, significantly affecting the structure and mechanical properties of the fiber body.

[0060] Table 2 Properties of the fibers obtained in each comparative example in this experiment

[0061] Finally, it should be noted that the above examples are only some specific embodiments of the present invention. Obviously, the present invention is not limited to the above examples, and there are many variations. All variations that can be directly derived or associated with the content disclosed by a person skilled in the art should be considered as the protection scope of the present invention.

Claims

1. A pore-forming agent, characterized in that: For the preparation of highly water-absorbent microporous regenerated cellulose fibers, the preparation method of the pore-forming agent is as follows: Immerse the inorganic carbonate in the solvent, add an anionic surfactant, and then impregnate and compound at 0-10 °C for 5-30 min, and then separate the solid from the liquid. The obtained solid is the pore-forming agent; The mass ratio of the inorganic carbonate to the anionic surfactant is 100: 0.2-1.

0.

2. The pore-forming agent according to claim 1, characterized in that: The inorganic carbonate is magnesium carbonate, zinc carbonate, barium carbonate; The solvent is ethanol with a volume concentration of 90-95%; The anionic surfactant is a C n alkyl anionic surfactant, and the carbon chain length satisfies n≥12.

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

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

5. A preparation method of highly absorbent microporous regenerated cellulose fibers, comprising preparing a spinning solution from cellulose pulp, and then spraying it out from a spinneret hole and precipitating it in a coagulation bath to obtain fiber filaments; characterized in that: Using the pore-forming agent according to any one of claims 1-4, it includes the following steps: 1). Preparation of the composite spinning solution: According to the weight ratio of cellulose pulp: pore-forming agent = 100: 2-15, add the pore-forming agent to the spinning solution prepared from cellulose pulp, stir and mix evenly, and then defoam to obtain the composite spinning solution; 2). In the spinning step: add 1-5 g of a cationic surfactant to each liter of the coagulation bath to obtain a coagulation bath containing a cationic surfactant; Extrude the composite spinning solution from the spinneret holes into the coagulation bath containing the cationic surfactant, and precipitate in the coagulation bath to obtain microporous fiber filaments; 3). The microporous fiber filaments are post-treated to obtain highly water-absorbent microporous regenerated cellulose fibers.

6. The preparation method of the highly water-absorbent microporous regenerated cellulose fiber according to claim 5, characterized in that: The cationic surfactant is a C n alkyl cationic surfactant with a carbon chain length satisfying n≥1.

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

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