Environment-friendly flame-retardant lyocell fabric and preparation method thereof

Abstract

The invention relates to the technical field of textile engineering, and particularly discloses an environment-friendly flame-retardant lyocell fabric and a preparation method of the environment-friendly flame-retardant lyocell fabric. The preparation method comprises the following steps: sequentially dipping lyocell fabric in a chitosan solution, an adenosine triphosphate solution and a polyethyleneimine solution, repeating the operations of dipping, washing and drying, and finally carrying out solid drying to obtain the layer-by-layer self-assembled flame-retardant lyocell fabric, the layer-by-layer self-assembled flame-retardant lyocell fabric prepared by the invention not only has excellent flame retardance and can effectively inhibit flame spreading, but also has good washing resistance and stability, has the characteristics of soft hand feeling and skin-friendly texture, is high in light fastness and weather fastness, and has wide application prospects in the fields of safety protection, home textile and the like.

Description

Technical Field

[0001] This invention belongs to the field of textile engineering technology, specifically relating to an environmentally friendly flame-retardant lyocell fabric and its preparation method. Background Technology

[0002] In modern life, textiles are widely used in various fields such as home furnishings, clothing, and decoration, greatly improving the quality of life. However, the cellulose materials abundant in textiles, such as cotton and Lyocell fibers, are rich in hydrocarbons and have high flammability. When exposed to a source of ignition, they are highly flammable and spread rapidly, becoming a major cause of fires. According to relevant data, fires caused by textiles account for a high proportion, seriously threatening people's lives and property. Therefore, there is an urgent need for flame-retardant treatment of textiles.

[0003] Currently, there are numerous technical approaches to achieving flame retardancy in textiles. Among them, post-treatment flame retardant technology has become the mainstream method in industrial production due to its high process flexibility and wide applicability. This technology imparts flame retardant properties to the fabric surface by applying flame retardants, but this method has significant drawbacks. On the one hand, most post-treatment flame-retardant fabrics have poor wash resistance; with increasing washing cycles, the flame retardant gradually detaches, leading to a significant decrease in flame retardant effect. On the other hand, some highly effective flame retardant processes, such as treatment technology using hydroxymethyl groups as active groups, while ensuring that the fabric maintains good flame retardancy after multiple washes, release harmful substances such as formaldehyde during production and use, seriously endangering human health and the ecological environment.

[0004] With the deepening of environmental protection concepts and the increasing demands for green and sustainable development, the development of new flame-retardant technologies for textiles that combine high efficiency in flame retardancy and washability while meeting environmental standards is urgently needed. In recent years, researchers have attempted to address these issues by innovating the molecular structure of flame retardants and developing novel processing techniques. For example, they have explored the application of phosphate ester-phosphonate oligomers, utilizing the synergistic flame-retardant effects of elements such as P, N, and Si, and experimented with new technologies such as layer-by-layer self-assembly and plasma treatment. However, these methods still face technical bottlenecks in practical applications, making it difficult to achieve a perfect balance between flame retardancy, durability, and environmental friendliness. Furthermore, for emerging green fibers such as Lyocell, traditional flame-retardant treatments not only affect their natural feel and texture but also fail to meet their stringent requirements for flame retardancy and washability in specific applications. Therefore, finding green, environmentally friendly, low-cost, and efficient flame-retardant technologies for textiles remains a key challenge that the industry urgently needs to overcome.

[0005] Patent No. 202311554675.6 discloses a flame-retardant lyocell fabric and its preparation method. It uses melamine and chloropropyl-POSS as the main raw materials to react and obtain a substituted product of melamine and chloropropyl-POSS. Then, formaldehyde, the substituted product and lyocell fabric are reacted to obtain the flame-retardant lyocell fabric. Although this invention has certain improvements, it also faces problems such as complex production process, high cost, and environmental hazards due to the use of formaldehyde crosslinking, which limits its widespread application in more scenarios.

[0006] Furthermore, the aforementioned Lyocell fabric uses melamine and chloropropyl-POSS as the main raw materials. After a substitution reaction, it is bonded to the Lyocell fabric with a formaldehyde crosslinking agent. The melamine raw material used in this method is prone to decomposition at high temperatures, producing irritating gases, and formaldehyde, as a crosslinking agent, poses a residual risk, resulting in poor environmental performance. In addition, the substitution reaction steps are cumbersome, have stringent reaction conditions, and result in high production costs and low production efficiency. At the same time, the chemical crosslinking process easily damages the original structure of Lyocell fibers, leading to a stiffer fabric feel and reduced flexibility and drape. Moreover, its flame-retardant properties depend on the stability of the chemical crosslinking. After long-term use or repeated washing, the crosslinking structure may degrade, making it difficult to maintain the flame-retardant effect for a long time, thus limiting the application of the product in high-end and durable demand scenarios. Summary of the Invention

[0007] The purpose of this invention is to provide a method for preparing an environmentally friendly flame-retardant lyocell fabric, so as to solve the problems mentioned in the background art.

[0008] To achieve the above objectives, the present invention provides the following technical solution:

[0009] A method for preparing an environmentally friendly flame-retardant Lyocell fabric includes the following steps;

[0010] S1. Dissolve chitosan in acetic acid solution to prepare chitosan solution;

[0011] S2. Dissolve adenosine triphosphate in deionized water to prepare an adenosine triphosphate solution;

[0012] S3. Dissolve polyethyleneimine in deionized water to prepare a polyethyleneimine solution;

[0013] S4. Next, immerse the Lyocell fabric in the chitosan solution, remove it after immersion, wash it with deionized water, and then dry it.

[0014] S5. Next, immerse the Lyocell fabric in a ATP solution, remove it after immersion, wash it with deionized water, and then dry it.

[0015] S6. Next, immerse the Lyocell fabric in a polyethyleneimine solution, remove it after immersion, wash it with deionized water, and then dry it.

[0016] S7. The Lyocell fabric is sequentially immersed in chitosan solution, adenosine triphosphate solution and polyethyleneimine solution, and the above immersion, washing and drying operations are repeated. Finally, it is dried to obtain a layer-by-layer self-assembled flame-retardant Lyocell fabric.

[0017] Preferably, the acetic acid solution in S1 is 1 wt%, and the chitosan solution in S1 is 0.5 wt%.

[0018] Preferably, the adenosine triphosphate solution in S2 is 3 wt%.

[0019] Preferably, the polyethyleneimine solution in S3 is 3 wt%.

[0020] Preferably, the immersion time in S4, S5 and S6 is 15 minutes.

[0021] Preferably, the drying temperature in S4, S5 and S6 is 100°C.

[0022] Preferably, the drying temperature in step S7 is 120°C.

[0023] Preferably, an environmentally friendly flame-retardant lyocell fabric is prepared using the above-described method for preparing an environmentally friendly flame-retardant lyocell fabric.

[0024] Compared with the prior art, the beneficial effects of the present invention are:

[0025] The layer-by-layer self-assembled flame-retardant lyocell fabric prepared by this invention not only has excellent flame-retardant properties and can effectively suppress the spread of flames, but also has good washability and stability. It is also soft to the touch, skin-friendly, and has high light and weather fastness, and has broad application prospects in the fields of safety protection and home textiles. Detailed Implementation

[0026] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0027] Example 1:

[0028] A method for preparing an environmentally friendly flame-retardant Lyocell fabric includes the following steps;

[0029] S1. Dissolve chitosan in a 1 wt% acetic acid solution to prepare a 0.5 wt% chitosan solution;

[0030] S2. Dissolve adenosine triphosphate in deionized water to prepare a 3wt% adenosine triphosphate solution;

[0031] S3. Dissolve polyethyleneimine in deionized water to prepare a 3wt% polyethyleneimine solution and adjust the pH to 7.

[0032] S4. Then immerse the Lyocell fabric in the chitosan solution for 15 minutes, remove it, wash it with deionized water, and then dry it at 100°C.

[0033] S5. Then immerse the Lyocell fabric in a ATP solution for 15 minutes, remove it, wash it with deionized water, and then dry it at 100°C.

[0034] S6. Then immerse the Lyocell fabric in the polyethyleneimine solution for 15 minutes, remove it, wash it with deionized water, and then dry it at 100°C.

[0035] S7. The Lyocell fabric is impregnated in chitosan solution, adenosine triphosphate solution and polyethyleneimine solution in sequence, and the above impregnation, washing and drying operations are repeated. Finally, it is dried at 120°C to obtain a layer-by-layer self-assembled flame-retardant Lyocell fabric.

[0036] Example 2:

[0037] A method for preparing an environmentally friendly flame-retardant Lyocell fabric includes the following steps;

[0038] S1. Dissolve chitosan in a 1 wt% acetic acid solution to prepare a 0.5 wt% chitosan solution;

[0039] S2. Dissolve adenosine triphosphate in deionized water to prepare a 3wt% adenosine triphosphate solution;

[0040] S3. Dissolve polyethyleneimine in deionized water to prepare a 3wt% polyethyleneimine solution;

[0041] S4. Then immerse the Lyocell fabric in the chitosan solution for 15 minutes, remove it, wash it with deionized water, and then dry it at 100°C.

[0042] S5. Then immerse the Lyocell fabric in a ATP solution for 15 minutes, remove it, wash it with deionized water, and then dry it at 100°C.

[0043] S6. Then immerse the Lyocell fabric in the polyethyleneimine solution for 15 minutes, remove it, wash it with deionized water, and then dry it at 100°C.

[0044] S7. The Lyocell fabric is impregnated in chitosan solution, adenosine triphosphate solution and polyethyleneimine solution in sequence, and the above impregnation, washing and drying operations are repeated. Finally, it is dried at 120°C to obtain a layer-by-layer self-assembled flame-retardant Lyocell fabric.

[0045] Comparative Example 1

[0046] The traditional padding method is used for Lyocell fabrics, and the specific steps are as follows:

[0047] S1. Chitosan (0.5 wt%), adenosine triphosphate (3 wt%), and polyethyleneimine (3 wt%) are mixed in a 1 wt% acetic acid solution and the pH is adjusted to 5.

[0048] S2. Immerse the Lyocell fabric in the above mixture for 15 minutes;

[0049] S3. Then remove it, wash it with deionized water, and dry it at 100°C.

[0050] S4. Finally, dry at 120℃ to obtain a one-time coated flame-retardant Lyocell fabric.

[0051] Comparative Example 2

[0052] Lyocell fabrics are treated with a single chitosan, without the need for layer-by-layer assembly. The specific steps are as follows:

[0053] S1. Dissolve chitosan in a 1 wt% acetic acid solution to prepare a 0.5 wt% chitosan solution;

[0054] S2. Immerse the Lyocell fabric in the chitosan solution for 15 minutes and then remove it.

[0055] S3. Then remove it, wash it with deionized water, and dry it at 100°C.

[0056] S4. Finally, the fabric is dried at 120℃ to obtain flame-retardant Lyocell fabric.

[0057] Characterization data and effect data of the products in the examples and comparative examples

[0058]

[0059] Supplement the above data comparison and analysis results

[0060] Regarding flame retardant performance, the limiting oxygen index (LOI) of Examples 1 and 2 reached 32.5% and 34.2%, respectively, significantly higher than that of Comparative Example 1 (26.8%) and Comparative Example 2 (20.5%). According to industry standards, an LOI > 26% meets the flame retardant requirements, and the LOI of the product of this invention exceeds 32%, reaching the flame-retardant level. The layer-by-layer self-assembly process improves the LOI by 21.3%-27.6% compared to the traditional padding method and by 58.5%-66.8% compared to single chitosan treatment, verifying the synergistic flame retardant effect of phosphorus (adenosine triphosphate), nitrogen (polyethyleneimine), and chitosan. Vertical burning tests showed that the embodiment achieved zero afterflame (0s), smoldering for 0-1s, and damage of 5-8cm, which was far superior to Comparative Example 1 (afterflame 8s / smoldering 12s / damage 18cm) and Comparative Example 2 (afterflame 15s / smoldering 20s / damage 25cm). This indicates that its flame-retardant coating inhibits flame spread through char formation barrier and gas phase flame retardancy, while traditional processes are insufficient in effect because they cannot form a stable barrier.

[0061] In terms of wash resistance, the LOI retention rate of Example 1 reached 92%-95% after 50 washes, which is much higher than that of Comparative Example 1 (58%) and Comparative Example 2 (32%). The core mechanism is that layer-by-layer self-assembly forms a dense and firm multilayer structure through electrostatic and intermolecular forces of oppositely charged substances, rather than simple adhesion; the traditional padding method results in weak bonding due to disordered agglomeration of substances, and the single chitosan treatment is prone to detachment due to lack of cross-linking, both of which cause performance degradation. In terms of sensory properties, the whiteness of Example 1 is 73.8-75.3, which is slightly lower than that of the comparative example, but there is no obvious yellowing, and the soft hand feel and drape of Lyocell fabric are retained, while traditional processes are prone to hardening of the hand feel.

[0062] This invention uses chitosan (a natural polysaccharide) and adenosine triphosphate (ATP) (a biomolecule) to replace toxic raw materials such as melamine and formaldehyde, complying with EU REACH regulations and making it more suitable for high-end textile applications. Furthermore, this application eliminates the need for cross-linking agents such as formaldehyde, forming a stable coating through electrostatic adsorption, avoiding the negative impact of cross-linking reactions on the fabric's feel and strength, while simplifying the process. The flame-retardant lyocell fabric prepared using this application constructs a nanoscale multilayer membrane structure with natural biomass materials. While retaining the natural advantages of lyocell fibers such as softness, skin-friendliness, breathability, and moisture absorption, it achieves halogen-free, environmentally friendly flame retardancy. It not only rapidly chars upon contact with fire for heat insulation but also maintains stable performance after multiple washes, possessing both abrasion resistance and dimensional stability. Combining green environmental protection with practical functionality, it has enormous application potential.

[0063] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for preparing an environmentally friendly flame-retardant lyocell fabric, characterized in that, Includes the following steps; S1. Dissolve chitosan in acetic acid solution to prepare chitosan solution; S2. Dissolve adenosine triphosphate in deionized water to prepare an adenosine triphosphate solution; S3. Dissolve polyethyleneimine in deionized water to prepare a polyethyleneimine solution; S4. Next, immerse the Lyocell fabric in the chitosan solution, remove it after immersion, wash it with deionized water, and then dry it. S5. Next, immerse the Lyocell fabric in a ATP solution, remove it after immersion, wash it with deionized water, and then dry it. S6. Next, immerse the Lyocell fabric in a polyethyleneimine solution, remove it after immersion, wash it with deionized water, and then dry it. S7. The Lyocell fabric is sequentially immersed in chitosan solution, adenosine triphosphate solution and polyethyleneimine solution, and the above immersion, washing and drying operations are repeated. Finally, it is dried to obtain a layer-by-layer self-assembled flame-retardant Lyocell fabric.

2. The method for preparing an environmentally friendly flame-retardant lyocell fabric according to claim 1, characterized in that: The acetic acid solution in S1 is 1 wt%, and the chitosan solution in S1 is 0.5 wt%.

3. The method for preparing an environmentally friendly flame-retardant lyocell fabric according to claim 2, characterized in that: The adenosine triphosphate solution in S2 is 3 wt%.

4. The method for preparing an environmentally friendly flame-retardant lyocell fabric according to claim 3, characterized in that: The polyethyleneimine solution in S3 is 3 wt%.

5. The method for preparing an environmentally friendly flame-retardant lyocell fabric according to claim 4, characterized in that: The immersion time in S4, S5 and S6 is 15 minutes.

6. The method for preparing an environmentally friendly flame-retardant lyocell fabric according to claim 5, characterized in that: The drying temperature in S4, S5 and S6 is 100℃.

7. The method for preparing an environmentally friendly flame-retardant lyocell fabric according to claim 6, characterized in that: The drying temperature in S7 is 120℃.

8. An environmentally friendly flame-retardant lyocell fabric, characterized in that: It is prepared by the method of any one of claims 1 to 7 for the preparation of an environmentally friendly flame-retardant lyocell fabric.

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