Flame-retardant antibacterial Lyocell fiber material as well as preparation method and application thereof

Abstract

The invention discloses a flame-retardant antibacterial Lyocell fiber material as well as a preparation method and application thereof, and belongs to the technical field of cellulose fiber material preparation. Comprising the following steps: (1) adding a chitosan solution into a flame retardant solution or dispersion liquid to prepare a microcapsule blending type flame retardant; (2) adding the microcapsule blended flame retardant and a cross-linking agent into a cellulose spinning solution to obtain a flame-retardant cellulose spinning solution; and (3) spinning the flame-retardant cellulose spinning solution by adopting a wet spinning process to obtain the flame-retardant antibacterial Lyocell fiber material. Chitosan is used for coating a phosphorus-containing flame retardant to construct a microcapsule blended flame retardant, the microcapsule blended flame retardant has good compatibility with cellulose, and the defects that a traditional blended cellulose spinning solution is prone to layering and uneven in dispersion are overcome.

Description

Technical Field

[0001] The present invention relates to the technical field of preparation of cellulose fiber materials, and in particular to a flame-retardant and antibacterial Lyocell fiber material and a preparation method and application thereof. Background Art

[0002] Cellulose, a macromolecular polysaccharide derived from natural plants, has attracted widespread attention due to its abundance, renewability and biodegradability. Lyocell fiber, a cellulose fiber prepared by wet spinning of N-methylmorpholine-N-oxide (NMMO), enjoys the reputation of "green fiber of the 21st century". However, Lyocell fiber is highly flammable due to its high content of hydrocarbons, which seriously threatens people's lives and property safety. Therefore, the development of flame-retardant Lyocell fiber has great practical significance.

[0003] So far, post-finishing, such as surface grafting, padding-drying-baking, and layer-by-layer assembly, is mostly used for flame retardancy and antibacterial properties of Lyocell fibers and their textiles. Surface grafting requires the development of grafted comonomers that can react with cellulose molecules. There are certain limitations on the molecular design of grafted comonomers, high grafting efficiency, and high costs. In order to achieve the ideal flame retardant and antibacterial effects, a high grafting rate is required, which will deteriorate the feel of the fibers and fabrics and seriously affect their practicality. The padding-drying-baking process is relatively simple, but it also has the problem of reduced feel of the fibers and fabrics, and there are generally problems of yellowing and poor washability of the fibers and fabrics. Although the layer-by-layer self-assembly process is simple, it has the disadvantages of being time-consuming and the modification effect is not durable. Therefore, it is urgent to develop a modification method that does not affect the feel of Lyocell fibers and can improve their washability.

[0004] In recent years, the development of high-performance materials using biomass resources to replace petroleum-derived chemicals has become a key direction of sustainable development strategies. Chitosan (CS) is the product of N-deacetylation of chitin and is the only alkaline polysaccharide among natural polysaccharides. It has a similar chemical structure to cellulose and good compatibility with cellulose. It has biodegradability, biocompatibility, non-toxicity, antibacterial, and anti-cancer functions. It is widely used in textiles, beauty care, cosmetics, antibacterial agents, medical fibers, medical dressings, artificial tissue materials, and many other fields. However, there are no reports on the use of Lyocell fibers to prepare flame retardant materials. Summary of the invention

[0005] The purpose of the present invention is to provide a flame retardant and antibacterial Lyocell fiber material and its preparation method and application to solve the problems existing in the above-mentioned prior art. The present invention discloses a method for preparing a flame retardant and antibacterial Lyocell fiber by constructing a microcapsule blended flame retardant and blended with the flame retardant and antibacterial Lyocell fiber. The technical solution is simple and easy to operate, suitable for large-scale industrial production, and in line with the concept of sustainable development of society. While giving Lyocell fiber good flame retardant properties, it can also give it antibacterial properties and flame retardant durability.

[0006] To achieve the above object, the present invention provides the following solutions:

[0007] One of the technical solutions of the present invention is a method for preparing a flame retardant and antibacterial Lyocell fiber material, comprising the following steps:

[0008] (1) adding chitosan solution into flame retardant solution or dispersion to prepare microcapsule blended flame retardant;

[0009] (2) adding the microcapsule blended flame retardant and the crosslinking agent into a cellulose spinning solution to obtain a flame-retardant cellulose spinning solution;

[0010] (3) The flame-retardant cellulose spinning solution is spun by a wet spinning process to obtain the flame-retardant and antibacterial Lyocell fiber material.

[0011] The second technical solution of the present invention is the flame-retardant and antibacterial Lyocell fiber material prepared by the preparation method.

[0012] The third technical solution of the present invention is the use of the flame retardant and antibacterial Lyocell fiber material in the preparation of flame retardant products.

[0013] A fourth technical solution of the present invention is a flame retardant product, comprising the flame retardant and antibacterial Lyocell fiber material.

[0014] Based on the above technical solution, the present invention has the following technical effects:

[0015] (1) The microcapsule blended flame retardant is constructed by coating the phosphorus-containing flame retardant with chitosan, which has good compatibility with cellulose and avoids the defects of easy stratification and uneven dispersion of the traditional blended cellulose spinning solution; the microcapsule blended flame retardant not only has a good PN synergistic flame retardant effect, but also the polyhydroxy structure is compatible with cellulose molecules and produces a large number of hydrogen bonds, which greatly improves the compatibility and anti-migration performance of the flame retardant with the cellulose matrix. Finally, the durable flame retardant and antibacterial Lyocell fiber is obtained, and its limiting oxygen index value can reach up to 39.2%, and the antibacterial rate against Escherichia coli and Staphylococcus is more than 99%.

[0016] (2) The blended flame retardant constructed by microcapsule coating technology can give full play to the synergistic flame retardant effect of acid source, carbon source and gas source, with high flame retardant efficiency, small addition amount, and can well retain the excellent properties of the original Lyocell fiber.

[0017] (3) Based on the cross-linking effect of the cross-linking agent, the blended flame retardant and the cellulose, the durable flame retardancy of Lyocell fiber is achieved.

[0018] (4) This technical solution is simple and easy to operate, low in cost, good in modification effect, and suitable for large-scale preparation. DETAILED DESCRIPTION

[0019] Now, various exemplary embodiments of the present invention are described in detail. The methods in the examples are conventional methods unless otherwise specified, and the reagents used are conventional commercially available reagents or reagents prepared by conventional methods unless otherwise specified. This detailed description should not be considered as a limitation of the present invention, but should be understood as a more detailed description of certain aspects, features and embodiments of the present invention.

[0020] It should be understood that the terms described in the present invention are only for describing a particular embodiment and are not intended to limit the present invention. In addition, for the numerical range in the present invention, it should be understood that each intermediate value between the upper and lower limits of the scope is also specifically disclosed. The intermediate value in any stated value or stated range, and each smaller range between any other stated value or intermediate value in the described range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

[0021] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

[0022] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments of the present invention description without departing from the scope or spirit of the present invention. Other embodiments derived from the present invention description will be apparent to the skilled artisan. The present invention description and examples are exemplary only.

[0023] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0024] The technical solutions described in the present invention, unless otherwise specified, are all conventional solutions in the art, and the reagents or raw materials used, unless otherwise specified, are purchased from commercial channels or have been disclosed.

[0025] The embodiment of the present invention provides a method for preparing a flame retardant and antibacterial Lyocell fiber material, comprising the following steps:

[0026] (1) adding a chitosan solution to a flame retardant solution or dispersion to prepare a microcapsule blended flame retardant; the shell layer material of the microcapsule blended flame retardant is chitosan, and the core layer is a phosphorus-containing flame retardant;

[0027] (2) adding the microcapsule blended flame retardant and the crosslinking agent into a cellulose spinning solution to obtain a flame-retardant cellulose spinning solution;

[0028] (3) The flame-retardant cellulose spinning solution is spun by a wet spinning process to obtain the flame-retardant and antibacterial Lyocell fiber material.

[0029] In some specific embodiments, the chitosan in the chitosan solution is chitosan with a deacetylation degree of 80% to 95% and a relative molecular mass of 5000-10000; the solvent of the chitosan solution is acetic acid (analytical grade); and the concentration of the chitosan solution is 0.5wt% to 1.5wt%.

[0030] In some specific embodiments, the flame retardant in the flame retardant solution is selected from at least one of ammonium polyphosphate, diammonium phosphate, diammonium hydrogen phosphate, ammonium phosphate, melamine pyrophosphate and melamine cyanuric acid; the particle size of the flame retardant is 200-500 mesh; the concentration of the flame retardant solution is 20wt%-30wt%.

[0031] In some specific embodiments, the volume ratio of the chitosan solution to the flame retardant solution or dispersion is 1:(1-3).

[0032] In some specific embodiments, the cross-linking agent is selected from any one of 1,2,3,4-butanetetracarboxylic acid (BTCA), genipin, glycidyl ether and epoxidized soybean oil.

[0033] In some specific embodiments, the preparation method of the cellulose spinning solution is: dissolving cellulose in an NMMO aqueous solution to obtain the cellulose spinning solution;

[0034] The concentration of the NMMO aqueous solution is 85wt%-87wt%; the mass ratio of the cellulose to the NMMO aqueous solution is (8-15):100.

[0035] In some specific embodiments, the mass ratio of the microcapsule blended flame retardant, the crosslinking agent and the cellulose in the cellulose spinning solution is 1:(0.03-0.5):(3-10), preferably 1:(0.03-0.2):(3-4).

[0036] The embodiment of the present invention also provides a flame-retardant and antibacterial Lyocell fiber material prepared by the preparation method.

[0037] The embodiment of the present invention also provides the use of the flame-retardant and antibacterial Lyocell fiber material in the preparation of flame-retardant products.

[0038] An embodiment of the present invention further provides a flame retardant product, comprising the flame retardant and antibacterial Lyocell fiber material.

[0039] Based on the principle of "similar compatibility of molecular structures", the present invention discloses a microcapsule blended flame retardant based on chitosan and a phosphorus-containing flame retardant and a flame-retardant and antibacterial Lyocell fiber blended therewith.

[0040] Example 1

[0041] (1) Preparation of microcapsule blended flame retardant: chitosan with a deacetylation degree of 80% and a relative molecular mass of 5000 is dissolved in acetic acid (analytical grade) to prepare a solution with a concentration of 1.5wt%; ammonium polyphosphate with a particle size of 200 mesh is dissolved in water to prepare a 20wt% flame retardant solution; the chitosan solution is slowly added dropwise to the flame retardant solution or dispersion under high-speed stirring to prepare the microcapsule blended flame retardant.

[0042] (2) Preparation of flame-retardant cellulose spinning solution: The concentration of a commercially available 50 wt% NMMO aqueous solution is increased to 85 wt% by vacuum distillation to dissolve cellulose pulp; cellulose accounts for 8 wt% of the NMMO aqueous solution system; genipin accounts for 1% of the cellulose mass; the microcapsule blended flame retardant and genipin prepared in step (1) are added to the above-mentioned cellulose spinning solution, wherein the microcapsule blended flame retardant accounts for 15 wt% of the cellulose mass, and after being uniformly mixed and defoamed, they are set aside for later use.

[0043] (3) Spinning of flame-retardant and antibacterial Lyocell fibers: The spinning solution was ejected through a spinneret into a coagulation bath to obtain primary fibers using a wet spinning process. The spinning speed was 60 m / min and the air gap length was 5 cm. The fibers were then stretched, washed, dried, and wound to obtain flame-retardant and antibacterial Lyocell fibers.

[0044] The flame retardancy and antibacterial properties of the blended flame retardant and antibacterial Lyocell fibers were tested according to the methods in "GB / T 5454-1997 Textiles Burning Performance Test - Oxygen Index Method" and "GB / T 20944.3-200 Evaluation of Antibacterial Properties of Textiles" Part 3: Oscillation Method. The results showed that the limiting oxygen index (LOI) value of the flame retardant and antibacterial Lyocell fiber was 28.3%, and the antibacterial rates against Escherichia coli and Staphylococcus aureus were both over 99%.

[0045] Example 2

[0046] (1) Preparation of microcapsule blended flame retardant: chitosan with a deacetylation degree of 90% and a relative molecular mass of 8000 was dissolved in acetic acid (analytical grade) to prepare a solution with a concentration of 1.0 wt%; 200-mesh ammonium polyphosphate and 300-mesh melamine phosphate were dissolved in water at a mass ratio of 1:1 to prepare a 25 wt% flame retardant solution; the chitosan solution was slowly added dropwise to the flame retardant solution or dispersion under high-speed stirring to prepare the microcapsule blended flame retardant.

[0047] (2) Preparation of flame-retardant cellulose spinning solution: The concentration of a commercially available 50 wt% NMMO aqueous solution is increased to 85 wt% by vacuum distillation to dissolve cellulose pulp; cellulose accounts for 12 wt% of the NMMO aqueous solution system; BTCA accounts for 2% of the cellulose mass; the microcapsule blended flame retardant and BTCA prepared in step (1) are added to the above-mentioned cellulose spinning solution, wherein the microcapsule blended flame retardant accounts for 25 wt% of the cellulose mass, and after being uniformly mixed and defoamed, they are set aside for later use.

[0048] (3) Spinning of flame-retardant and antibacterial Lyocell fibers: The spinning solution was ejected through a spinneret into a coagulation bath to obtain primary fibers using a wet spinning process. The spinning speed was 90 m / min and the air gap length was 5 cm. The fibers were then stretched, washed, dried, and wound to obtain flame-retardant and antibacterial Lyocell fibers.

[0049] The flame retardancy and antibacterial properties of the blended flame retardant and antibacterial Lyocell fibers were tested according to the methods in "GB / T 5454-1997 Textiles Burning Performance Test - Oxygen Index Method" and "GB / T 20944.3-200 Evaluation of Antibacterial Properties of Textiles" Part 3: Oscillation Method. The results showed that the limiting oxygen index (LOI) value of the flame retardant and antibacterial Lyocell fiber was 35.7%, and the antibacterial rates against Escherichia coli and Staphylococcus aureus were both over 99%.

[0050] Example 3

[0051] (1) Preparation of microcapsule blended flame retardant: chitosan with a deacetylation degree of 95% and a relative molecular mass of 10,000 was dissolved in acetic acid (analytical grade) to prepare a solution with a concentration of 0.5 wt%; 200-mesh melamine phosphate and 500-mesh melamine pyrophosphate were dispersed in water at a mass ratio of 2:1 to prepare a 25 wt% flame retardant solution; the chitosan solution was slowly added dropwise to the flame retardant solution or dispersion under high-speed stirring to prepare a microcapsule blended flame retardant.

[0052] (2) Preparation of flame-retardant cellulose spinning solution: The concentration of a commercially available 50 wt% NMMO aqueous solution is increased to 85 wt% by vacuum distillation to dissolve cellulose pulp; cellulose accounts for 15 wt% of the NMMO aqueous solution system; glycidyl ether accounts for 5% of the cellulose mass; the microcapsule blended flame retardant and glycidyl ether prepared in step (1) are added to the above-mentioned cellulose spinning solution, wherein the microcapsule blended flame retardant accounts for 25 wt% of the cellulose mass, and after being uniformly mixed and defoamed, they are set aside for use.

[0053] (3) Spinning of flame-retardant and antibacterial Lyocell fibers: The spinning solution was ejected through a spinneret into a coagulation bath to obtain primary fibers using a wet spinning process. The spinning speed was 110 m / min and the air gap length was 5 cm. The fibers were then stretched, washed, dried, and wound to obtain flame-retardant and antibacterial Lyocell fibers.

[0054] The flame retardancy and antibacterial properties of the blended flame retardant and antibacterial Lyocell fibers were tested according to the methods in "GB / T 5454-1997 Textiles Burning Performance Test - Oxygen Index Method" and "GB / T 20944.3-200 Evaluation of Antibacterial Properties of Textiles" Part 3: Oscillation Method. The results showed that the limiting oxygen index (LOI) value of the flame retardant and antibacterial Lyocell fiber was 40.3%, and the antibacterial rates against Escherichia coli and Staphylococcus aureus were both over 99%.

[0055] Comparative Example 1

[0056] (1) Preparation of cellulose spinning solution: The concentration of commercially available 50 wt% NMMO aqueous solution was increased to 85 wt% by vacuum distillation to dissolve cellulose pulp; cellulose accounted for 15 wt% of the NMMO aqueous solution system; after being dissolved and defoamed, it was set aside for later use.

[0057] (2) Spinning of cellulose fibers: Using a wet spinning process, the spinning solution is ejected through a spinneret into a coagulation bath to obtain primary fibers. The spinning speed is 110 m / min and the air gap length is 5 cm. Lyocell fibers are then drawn, washed, dried, and wound.

[0058] The flame retardancy and antibacterial properties of Lyocell fiber were tested according to the methods in "GB / T 5454-1997 Textiles Burning Performance Test - Oxygen Index Method" and "GB / T 20944.3-200 Evaluation of Antibacterial Properties of Textiles" Part 3: Oscillation Method. The results showed that the limiting oxygen index (LOI) value of Lyocell fiber was 18.6%, and the antibacterial rates against Escherichia coli and Staphylococcus were zero.

[0059] The properties of the fibers prepared in Examples 1 to 3 and Comparative Example 1 are shown in Table 1.

[0060] Table 1 Performance of different microcapsule blended flame retardant Lyocell fibers

[0061]

[0062]

[0063] As can be seen from Table 1, the LOI value of the Lyocell fiber prepared without adding flame retardants and cross-linking agents is only 18.6%, which is a highly flammable fiber material. As the content of flame retardants increases, its LOI value increases sharply and reaches as high as 40.3%, with excellent flame retardant properties. After 30 washes, although the LOI value of the flame retardant fiber has decreased, it is still higher than 35%, and it is still a flame-retardant fiber material, showing good washing durability. Due to the addition of cross-linking agents, the mechanical properties of the flame-retardant and antibacterial Lyocell fiber are improved compared with the control example. The fiber of comparative example 1 has no antibacterial properties against Escherichia coli and Staphylococcus, while the antibacterial rates of all embodiments 1 to 3 against Escherichia coli and Staphylococcus reach 99.9%, with very excellent antibacterial properties. These results greatly reflect the beneficial value and development advantages of the present invention.

[0064] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation methods of the present invention. For ordinary technical users in the relevant field, other different forms of changes or modifications can be made on the basis of the above description. It is not necessary and impossible to list all the implementation methods here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A method for preparing a flame retardant and antibacterial Lyocell fiber material, characterized in that: The following steps are involved: (1) adding chitosan solution into flame retardant solution or dispersion to prepare microcapsule blended flame retardant; (2) adding the microcapsule blended flame retardant and the crosslinking agent into a cellulose spinning solution to obtain a flame-retardant cellulose spinning solution; (3) The flame-retardant cellulose spinning solution is spun by a wet spinning process to obtain the flame-retardant and antibacterial Lyocell fiber material.

2. The preparation method according to claim 1, characterized in that: The chitosan in the chitosan solution is chitosan with a deacetylation degree of 80% to 95% and a relative molecular mass of 5000-10000; the solvent of the chitosan solution is acetic acid; and the concentration of the chitosan solution is 0.5wt% to 1.5wt%.

3. The preparation method according to claim 1, characterized in that: The flame retardant in the flame retardant solution is selected from at least one of ammonium polyphosphate, diammonium phosphate, diammonium hydrogen phosphate, ammonium phosphate, melamine pyrophosphate and melamine cyanuric acid; the particle size of the flame retardant is 200-500 mesh; the concentration of the flame retardant solution is 20wt%-30wt%.

4. The preparation method according to claim 1, characterized in that: The volume ratio of the chitosan solution to the flame retardant solution or dispersion is 1:(1-3).

5. The preparation method according to claim 1, characterized in that: The crosslinking agent is selected from any one of 1,2,3,4-butanetetracarboxylic acid (BTCA), genipin, glycidyl ether and epoxidized soybean oil.

6. The preparation method according to claim 1, characterized in that: The preparation method of the cellulose spinning solution is as follows: dissolving cellulose in an NMMO aqueous solution to obtain the cellulose spinning solution; The concentration of the NMMO aqueous solution is 85wt%-87wt%; the mass ratio of the cellulose to the NMMO aqueous solution is (8-15):

100.

7. The preparation method according to claim 1, characterized in that: The mass ratio of the microcapsule blended flame retardant, the crosslinking agent and the cellulose in the cellulose spinning solution is 1:(0.03-0.5):(3-10).

8. The flame-retardant and antibacterial Lyocell fiber material prepared by the preparation method according to any one of claims 1 to 7.

9. Use of the flame-retardant and antibacterial Lyocell fiber material as claimed in claim 8 in the preparation of flame-retardant products.

10. A flame retardant product, characterized in that: Comprising the flame retardant and antibacterial Lyocell fiber material as described in claim 8.

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