Multifunctional regenerated cellulose fiber and preparation method thereof

Abstract

The present invention relates to a multifunctional regenerated cellulose fiber and a preparation method thereof, belonging to the technical field of textile finishing. The preparation method comprises the following steps: S1, adding wormwood essential oil and chitosan solution to a sodium alginate / ammonium polyphosphate mixture in sequence, reacting under acidic conditions, filtering and drying to obtain multifunctional microcapsules with wormwood essential oil as a core material and chitosan, sodium alginate, and ammonium polyphosphate as wall materials; S2, blending the multifunctional microcapsules with a spinning solution, wet spinning, coagulation molding, washing, non-oxidative desulfurization, and drying to obtain a multifunctional regenerated cellulose fiber. The multifunctional regenerated cellulose fiber of the present invention has excellent antibacterial properties, flame retardant properties, and water-washing resistance. The antibacterial rates against Escherichia coli and Staphylococcus aureus are both higher than 97.3%, and the antibacterial rates are still higher than 86.7% after 50 water washings. The limiting oxygen index of the multifunctional regenerated cellulose fiber exceeds 29.5%, and the limiting oxygen index is still higher than 27.1% after 50 water washings.

Description

Technical Field

[0001] The invention belongs to the technical field of textile finishing, and in particular relates to a multifunctional regenerated cellulose fiber and a preparation method thereof. Background Art

[0002] Regenerated cellulose fiber, with its excellent moisture absorption, breathability, and comfort, is widely used in clothing, home decor, and other fields. As people's demands for a better quality of life continue to rise, the safety and health benefits of textiles are gaining increasing attention. However, the poor antimicrobial properties and high fire hazard of regenerated cellulose fiber products severely limit their application in the textile industry. Improving the antimicrobial and fire safety properties of regenerated cellulose fiber is particularly important.

[0003] Mugwort extract, rich in natural substances such as flavonoids, terpenes, eucalyptol, and tannins, has excellent antimicrobial properties and has therefore attracted widespread attention for the antimicrobial functionalization of textiles. Chinese invention patent CN107268096A discloses a method for preparing mugwort antimicrobial viscose fiber. The method involves adding mugwort extract to plant pulp to produce regenerated cellulose fiber. However, the mugwort extract is volatile, unstable, and poorly compatible with regenerated cellulose fiber, resulting in poor durability of the functional regenerated cellulose fiber. Microencapsulation technology, with its excellent stability and sustained release properties, can effectively address this issue.

[0004] References (Zhai Yuanyuan, Liu Yanjun, Wang Jin, et al. Preparation and application of antibacterial microcapsules of mugwort essential oil [J]. Journal of Textile Science and Engineering, 2021, 38 (4): 50-56) Mugwort essential oil was used as the core material, gelatin and chitosan were used as the wall materials, and mugwort essential oil microcapsules were prepared by complex coacervation method. Then, cotton fabrics were post-finished with mugwort essential oil microcapsules through polyurethane coating. References (Sun Lijuan. Research on mugwort extract / viscose spunlace nonwoven materials [D]. Tianjin: Tianjin University of Technology, 2021) Sodium alginate and calcium chloride were used as the wall materials, mugwort extract was used as the core material, and mugwort extract microcapsules were prepared by sharp hole-coagulation bath method. The prepared mugwort extract microcapsules were then arranged on the surface of viscose fiber spunlace nonwoven materials. However, the particle size of the microcapsules was about 3 mm, which could not be applied to the addition and modification of functional regenerated cellulose fibers.

[0005] The flame retardant modification of regenerated cellulose fibers generally involves adding flame retardants directly to the spinning solution for spinning, and the amount of flame retardants used is generally high. Adding mugwort essential oil microcapsules and flame retardants to the spinning solution separately will cause serious damage to the strength of the regenerated cellulose fibers.

[0006] Therefore, how to organically combine the antibacterial components of mugwort essential oil and the flame retardant components and add them to regenerated cellulose fibers as an organic whole remains an urgent problem to be solved. Summary of the Invention

[0007] To solve the above technical problems, the present invention provides a multifunctional regenerated cellulose fiber and a preparation method thereof. First, multifunctional microcapsules are prepared using mugwort essential oil as the core material and oxidized sodium alginate, ammonium polyphosphate and chitosan as the wall materials, organically combining the flame retardant function and the antibacterial function; then the multifunctional microcapsules are added to the regenerated cellulose fiber spinning solution and mixed evenly, and the multifunctional regenerated cellulose fiber is prepared by wet spinning.

[0008] The first object of the present invention is to provide a method for preparing multifunctional regenerated cellulose fibers, comprising the following steps:

[0009] S1, adding wormwood essential oil and chitosan solution to the oxidized sodium alginate / ammonium polyphosphate mixture in sequence, reacting at a pH of 6-7, filtering and drying to obtain multifunctional microcapsules with wormwood essential oil as the core material and chitosan, oxidized sodium alginate and ammonium polyphosphate as the wall materials;

[0010] S2. The multifunctional microcapsules described in S1 are blended with a spinning solution, and the multifunctional regenerated cellulose fibers are obtained by wet spinning, coagulation molding, washing, non-oxidative desulfurization and drying; the spinning solution is a mixture of cellulose methyl and sodium hydroxide.

[0011] In one embodiment of the present invention, in S1, the mass fraction of the chitosan solution is 0.75%-1.25%, the pH of the chitosan solution is 3.5-4.5, the pH regulator is acetic acid and / or citric acid, and chitosan is easily soluble in acidic solutions.

[0012] In one embodiment of the present invention, in S1, the mass fraction of the oxidized sodium alginate solution in the mixed solution is 0.25%-0.5%, the mass fraction of the ammonium polyphosphate is 1.0%-1.5%, and the degree of polymerization of the ammonium polyphosphate is 10-15.

[0013] In one embodiment of the present invention, in S1, the mass ratio of chitosan to oxidized sodium alginate / ammonium polyphosphate is 1:2-3.

[0014] In one embodiment of the present invention, in S1, the diameter of the multifunctional microcapsule is 4 μm-6 μm, the mass ratio of the core material to the wall material is 1:2-3, and the embedding rate of the wormwood essential oil is 60%-65%.

[0015] In one embodiment of the present invention, in S1, the pH regulator is sodium hydroxide.

[0016] Furthermore, the mass fraction of the sodium hydroxide is 5%-10%.

[0017] In one embodiment of the present invention, in S1, the reaction temperature is 55°C-70°C, and the reaction time is 50min-70min. Under these conditions, the carboxyl group of the oxidized sodium alginate, the phosphate group of the ammonium polyphosphate and the amino group of the chitosan can produce an ionic bond. In addition, the aldehyde group of the oxidized sodium alginate can produce a Schiff base bond with the amino group of the chitosan to form a microcapsule wall material to encapsulate the wormwood essential oil.

[0018] In one embodiment of the present invention, in S1, the drying temperature is 30°C-50°C.

[0019] In one embodiment of the present invention, in S2, the maturity of the spinning solution (10 wt% NH4Cl) is 10 mL-15 mL.

[0020] In one embodiment of the present invention, in S2, the mass fraction of methyl cellulose in the spinning solution is 6%-9%, and the mass fraction of sodium hydroxide is 8%-12%; the amount of the multifunctional microcapsules is 9%-13% of the methyl cellulose content in the spinning solution.

[0021] In one embodiment of the present invention, in S2, the spinning speed of the wet spinning is 30 m / min-50 m / min, and the total draft is 120%-130%.

[0022] In one embodiment of the present invention, in S2, the coagulation molding is carried out in a coagulation bath, the temperature of the coagulation bath is 35°C-45°C; the concentration of sulfuric acid in the coagulation bath is 80g / L-120g / L, the concentration of sodium sulfate is 280g / L-350g / L, and the concentration of zinc sulfate is 10g / L-14g / L.

[0023] The second object of the present invention is to provide a multifunctional regenerated cellulose fiber prepared by the method.

[0024] The principle of the present invention is that the cationic amino groups of chitosan respectively undergo ionic bonding and Schiff base reaction with the anionic carboxyl groups and aldehyde groups of oxidized sodium alginate, and the cationic amino groups of chitosan can produce ionic bonding with the phosphate groups of ammonium polyphosphate to form a stable wall material structure, thereby encapsulating the wormwood essential oil to prepare multifunctional microcapsules; the flavonoid components and tannic acid components in the wormwood essential oil are rich in hydroxyl groups and have good compatibility with chitosan and oxidized sodium alginate; in addition, the main chains of chitosan and oxidized sodium alginate are both glucose rings, which have similar chemical structures to cellulose, so the chitosan / oxidized sodium alginate microcapsules have good compatibility with regenerated cellulose fibers and have little effect on the strength and feel of the regenerated cellulose fibers; the wormwood essential oil, Schiff base structure and chitosan construct a synergistic antibacterial effect, so the multifunctional microcapsules have excellent antibacterial properties, the wormwood essential oil is dispersed in the regenerated cellulose fibers in a microcapsule state, and its release and volatilization have a sustained release effect, so it has excellent durability.

[0025] Ammonium polyphosphate has a strong catalytic carbonization ability and high flame retardant efficiency. Chitosan releases non-combustible nitrogen-containing gas during combustion and plays a role in the gas phase, while sodium alginate oxide mainly acts as a carbonizing agent. The three interact with each other to form an expanding flame retardant system. Therefore, the ammonium polyphosphate / sodium alginate oxide / chitosan system has a high flame retardant efficiency; in addition, ammonium polyphosphate, sodium alginate oxide and chitosan form a stable bond to generate an insoluble wall material, and have good compatibility with regenerated cellulose fibers. They are combined with regenerated cellulose fibers through supramolecular forces, so the multifunctional microcapsules can be evenly dispersed in the regenerated cellulose fibers and have excellent water-washing resistance.

[0026] The technical solution of the present invention has the following advantages over the prior art:

[0027] (1) The preparation method described in the present invention uses mugwort essential oil as the core material and ammonium polyphosphate, sodium alginate oxide and chitosan as the wall materials to prepare antibacterial and flame-retardant multifunctional microcapsules, organically combining the flame-retardant function and the antibacterial function, and is used to prepare multifunctional regenerated cellulose fibers with long-lasting antibacterial and flame-retardant properties. The microcapsules have high flame-retardant and antibacterial efficiency, good durability, little effect on the mechanical properties of the regenerated cellulose fibers, and high promotion value.

[0028] (2) The multifunctional regenerated cellulose fiber of the present invention has excellent antibacterial properties, flame retardant properties and water-washing resistance. The antibacterial rates against Escherichia coli and Staphylococcus aureus are both higher than 97.3%, and the antibacterial rates are still higher than 86.7% after 50 water washings. The limiting oxygen index of the multifunctional regenerated cellulose fiber exceeds 29.5% (the limiting oxygen index of unmodified regenerated cellulose fiber is 18.1%), and the limiting oxygen index is still higher than 27.1% after 50 water washings. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to make the content of the present invention more clearly understood, the present invention is further described in detail below according to specific embodiments of the present invention in conjunction with the accompanying drawings, wherein:

[0030] Figure 1 This is a scanning electron microscope image of the multifunctional microcapsule prepared in Example 1 of the present invention;

[0031] Figure 2 This is a test chart of the antibacterial performance of the regenerated cellulose fibers of Comparative Example 1 and Example 1 of the present invention. DETAILED DESCRIPTION

[0032] The present invention will be further described below with reference to the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it. However, the embodiments are not intended to limit the present invention.

[0033] In the present invention, unless otherwise specified, the mass fraction of cellulose methyl ester in the spinning solution used in the examples is 8%, the mass fraction of sodium hydroxide is 10%; the maturity value of the spinning solution is about 13 mL at 10 wt% NH4Cl.

[0034] In the present invention, unless otherwise specified, the pH of the chitosan solution used in the examples is about 4, and the pH regulator is citric acid.

[0035] Example 1

[0036] The multifunctional regenerated cellulose fiber and the preparation method thereof of the present invention specifically comprise the following steps:

[0037] S1. Adding wormwood essential oil and 1% chitosan solution by mass to a sodium alginate / ammonium polyphosphate mixture in sequence, wherein the mass ratio of chitosan to sodium alginate / ammonium polyphosphate is 1:2.5, adding 8% sodium hydroxide by mass to adjust the pH to 6.5, reacting at 65°C for 60 minutes, filtering, and drying at 40°C to obtain multifunctional microcapsules with wormwood essential oil as the core material and chitosan, sodium alginate and ammonium polyphosphate as the wall materials; the mass fraction of the sodium alginate solution in the sodium alginate / ammonium polyphosphate mixture is 0.4%, the mass fraction of ammonium polyphosphate is 1.3%, and the degree of polymerization of ammonium polyphosphate is 12; the diameter of the multifunctional microcapsules is about 4.3 μm, the mass ratio of the core material to the wall material is 1:2.5, and the encapsulation efficiency of the wormwood essential oil is 63%;

[0038] S2. Blending multifunctional microcapsules with spinning solution, wherein the amount of multifunctional microcapsules is 11% of the type A cellulose content in the spinning solution, wet spinning is performed at a spinning speed of 40 m / min and a total draft of 125%, and coagulation molding is performed in a coagulation bath at 40°C, followed by washing, non-oxidative desulfurization, and drying to obtain multifunctional regenerated cellulose fibers; the spinning solution is a mixture of type A cellulose and sodium hydroxide; the concentration of sulfuric acid in the coagulation bath is 100 g / L, the concentration of sodium sulfate is 320 g / L, and the concentration of zinc sulfate is 12 g / L.

[0039] Comparative Example 1

[0040] The process is basically the same as Example 1, except that no multifunctional microcapsules are added, that is, the regenerated cellulose fibers are not modified.

[0041] Comparative Example 2

[0042] The method is basically the same as Example 1, except that chitosan is not added.

[0043] Example 2

[0044] The multifunctional regenerated cellulose fiber and the preparation method thereof of the present invention specifically comprise the following steps:

[0045] S1. Adding wormwood essential oil and chitosan solution with a mass fraction of 0.75% to a sodium alginate oxidized / ammonium polyphosphate mixture in sequence, wherein the mass ratio of chitosan to sodium alginate oxidized / ammonium polyphosphate is 1:2, adding 5% sodium hydroxide by mass to adjust the pH to 6, reacting at 55°C for 70 minutes, filtering, and drying at 30°C to obtain multifunctional microcapsules with wormwood essential oil as a core material and chitosan, sodium alginate oxidized, and ammonium polyphosphate as wall materials; the mass fraction of sodium alginate solution in the sodium alginate oxidized / ammonium polyphosphate mixture is 0.25%, the mass fraction of ammonium polyphosphate is 1.0%, and the degree of polymerization of ammonium polyphosphate is 10; the diameter of the multifunctional microcapsules is about 4 μm, the mass ratio of the core material to the wall material is 1:2, and the encapsulation efficiency of wormwood essential oil is 60%;

[0046] S2. Blending multifunctional microcapsules with spinning solution, wherein the amount of multifunctional microcapsules is 9% of the type A cellulose content in the spinning solution, wet spinning is performed at a spinning speed of 30 m / min and a total draft of 120%, and coagulation molding is performed in a coagulation bath at 35°C, followed by washing, non-oxidative desulfurization, and drying to obtain multifunctional regenerated cellulose fibers; the spinning solution is a mixture of type A cellulose and sodium hydroxide; the concentration of sulfuric acid in the coagulation bath is 80 g / L, the concentration of sodium sulfate is 280 g / L, and the concentration of zinc sulfate is 10 g / L.

[0047] Example 3

[0048] The multifunctional regenerated cellulose fiber and the preparation method thereof of the present invention specifically comprise the following steps:

[0049] S1. Adding wormwood essential oil and chitosan solution with a mass fraction of 1.25% to a sodium alginate oxidized / ammonium polyphosphate mixture in sequence, wherein the mass ratio of chitosan to sodium alginate oxidized / ammonium polyphosphate is 1:3, adding 10% sodium hydroxide by mass fraction to adjust the pH to 6, reacting at 70°C for 50 minutes, filtering, and drying at 50°C to obtain multifunctional microcapsules with wormwood essential oil as the core material and chitosan, sodium alginate oxidized and ammonium polyphosphate as the wall materials; the mass fraction of the sodium alginate oxidized solution in the sodium alginate oxidized / ammonium polyphosphate mixture is 0.5%, the mass fraction of the ammonium polyphosphate is 1.5%, and the degree of polymerization of the ammonium polyphosphate is 15; the diameter of the multifunctional microcapsules is about 6 μm, the mass ratio of the core material to the wall material is 1:3, and the encapsulation efficiency of the wormwood essential oil is 65%;

[0050] S2. Multifunctional microcapsules are blended with a spinning solution, wherein the amount of the multifunctional microcapsules is 13% of the cellulose A content in the spinning solution. Wet spinning is performed at a spinning speed of 50 m / min and a total draft of 130%. The fibers are coagulated and formed in a coagulation bath at 45°C, washed, non-oxidatively desulfurized, and dried to obtain multifunctional regenerated cellulose fibers. The spinning solution is a mixture of cellulose A and sodium hydroxide. The concentration of sulfuric acid in the coagulation bath is 120 g / L, the concentration of sodium sulfate is 350 g / L, and the concentration of zinc sulfate is 14 g / L.

[0051] Test Example 1

[0052] Based on Example 1, the prepared multifunctional microcapsules were characterized using scanning electron microscopy, and the results were as follows: Figure 1 As shown. Figure 1 It can be seen that the multifunctional microcapsules are mainly spherical and the particle size distribution is relatively uniform, indicating that the multifunctional microcapsules were successfully prepared.

[0053] Test Example 2

[0054] The properties of the modified regenerated cellulose fibers of Examples 1-3 and Comparative Examples 1-2 were tested.

[0055] The antibacterial properties of multifunctional regenerated cellulose fiber were tested with reference to GB / T 20944.3-2008 “Evaluation of antibacterial properties of textiles Part 3: Oscillation method”.

[0056] The strength of multifunctional regenerated cellulose fiber was tested with reference to GB / T 14337-2022 “Test method for tensile properties of chemical staple fibers”.

[0057] Wash according to AATCC-61-2013 "Color Fastness to Washing: Accelerated".

[0058] The limiting oxygen index of multifunctional regenerated cellulose fiber was tested with reference to FZ / T 50016-2011 “Test method for flame retardancy of viscose staple fibers - Oxygen index method”.

[0059] Figure 2 The antibacterial performance test chart of the unmodified regenerated cellulose fiber of Comparative Example 1 and the multifunctional regenerated cellulose fiber of Example 1 is as follows:

[0060] Table 1 shows the relevant performance parameters finally measured:

[0061] Table 1

[0062]

[0063]

[0064] From Table 1 and Figure 2 It can be seen that the antibacterial rate of unmodified regenerated cellulose fiber against Escherichia coli and Staphylococcus aureus is 0%, and the limiting oxygen index is 18.1%, indicating that its antibacterial and flame retardant properties are poor. The antibacterial rate of regenerated cellulose fiber modified with multifunctional microcapsules against Escherichia coli and Staphylococcus aureus exceeds 97.3%, and the antibacterial rate is still higher than 86.7% after 50 water washings. The limiting oxygen index of the modified regenerated cellulose fiber is higher than 29.1%, and the limiting oxygen index is still higher than 27.1% after 50 water washings, indicating that the multifunctional regenerated cellulose fiber has excellent antibacterial properties, flame retardant properties and water washing resistance. In addition, the dry breaking strength and wet breaking strength of the modified regenerated cellulose fiber are both reduced slightly, indicating that the multifunctional microcapsules are highly compatible with the regenerated cellulose fiber and that the multifunctional microcapsules have little effect on the strength properties of the regenerated cellulose fiber.

[0065] Compared with Comparative Example 2, the antibacterial property of the modified regenerated cellulose fiber is reduced when chitosan is not added. This is because the Schiff base structure cannot be formed and a synergistic antibacterial effect cannot be formed with the wormwood essential oil. In addition, after 50 washes, the antibacterial rates of the modified regenerated cellulose fiber against Escherichia coli and Staphylococcus aureus are reduced to 67.8% and 65.3%, respectively, indicating that its durability is poor. This is because microcapsules cannot be formed, resulting in a higher volatilization and loss rate of the wormwood essential oil.

[0066] Obviously, the above embodiments are merely examples for clarity of explanation and are not intended to limit the implementation methods. Those skilled in the art will appreciate that other variations or modifications can be made based on the above description. It is not necessary and impossible to enumerate all implementation methods here. Obvious variations or modifications arising therefrom remain within the scope of protection of the present invention.

Claims

1. A method for preparing multifunctional regenerated cellulose fiber, characterized in that: The following steps are included: S1. Adding wormwood essential oil and chitosan solution to a mixture of oxidized sodium alginate / ammonium polyphosphate in sequence, reacting at a pH of 6-7, filtering and drying to obtain multifunctional microcapsules with wormwood essential oil as a core material and chitosan, oxidized sodium alginate and ammonium polyphosphate as wall materials; the mass ratio of chitosan to oxidized sodium alginate / ammonium polyphosphate is 1:2-3; the reaction temperature is 55°C-70°C, and the reaction time is 50min-70min; S2. The multifunctional microcapsules described in S1 are blended with a spinning solution, and the multifunctional regenerated cellulose fibers are obtained by wet spinning, coagulation molding, washing, non-oxidative desulfurization and drying; the spinning solution is a mixture of cellulose methyl and sodium hydroxide.

2. The method for preparing multifunctional regenerated cellulose fiber according to claim 1, characterized in that: In S1, the mass fraction of the chitosan solution is 0.75%-1.25%, the pH of the chitosan solution is 3.5-4.5, and the pH regulator is acetic acid and / or citric acid; the mass fraction of the oxidized sodium alginate solution in the mixed solution is 0.25%-0.5%, the mass fraction of ammonium polyphosphate is 1.0%-1.5%, and the degree of polymerization of ammonium polyphosphate is 10-15.

3. The method for preparing multifunctional regenerated cellulose fiber according to claim 1, characterized in that: In S1, the diameter of the multifunctional microcapsule is 4 μm-6 μm, the mass ratio of the core material to the wall material is 1:2-3, and the embedding rate of the wormwood essential oil is 60%-65%.

4. The method for preparing multifunctional regenerated cellulose fiber according to claim 1, characterized in that: In S1, the pH regulator is sodium hydroxide.

5. The method for preparing multifunctional regenerated cellulose fiber according to claim 1, characterized in that: In S2, the mass fraction of cellulose methyl ester in the spinning solution is 6%-9%, and the mass fraction of sodium hydroxide is 8%-12%; the amount of the multifunctional microcapsules is 9%-13% of the cellulose methyl ester content in the spinning solution.

6. The method for preparing multifunctional regenerated cellulose fiber according to claim 1, characterized in that: In S2, the spinning speed of the wet spinning is 30 m / min-50 m / min, and the total draft is 120%-130%.

7. The method for preparing multifunctional regenerated cellulose fiber according to claim 1, characterized in that: In S2, the coagulation molding is carried out in a coagulation bath, the temperature of the coagulation bath is 35°C-45°C; the concentration of sulfuric acid in the coagulation bath is 80g / L-120g / L, the concentration of sodium sulfate is 280g / L-350g / L, and the concentration of zinc sulfate is 10g / L-14g / L.

8. Multifunctional regenerated cellulose fiber prepared by the method according to any one of claims 1 to 7.

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