Chitosan derivative composite shell flame-retardant fabric and preparation method and application thereof

Abstract

The application provides a chitosan derivative composite shell flame-retardant fabric and a preparation method and application thereof, and comprises the following steps: 0.1-0.3 mol of chitosan is dissolved in 500-1500 ml of 1-5 wt% acetic acid solution, 0.1-0.3 mol of bis(4-carboxyphenyl)phenyl phosphine oxide is added, the temperature is increased to 70-95 DEG C, and the temperature is kept for 3-5 h; after the reaction is completed, the product is filtered, washed and dried to obtain a polysaccharide derivative flame retardant. The fiber fabric is immersed in the chitosan solution for 1-30 min, dried, and dried at 50-80 DEG C for 2-6 hours; then, the fiber fabric is immersed in 1-5 wt% of a chitosan derivative flame retardant composite suspension for 1-30 min, dried, and dried at 50-80 DEG C for 2-6 hours; the operation is repeated for 1-20 times to obtain the chitosan derivative flame-retardant fabric. The preparation method of the application has the advantages of simple process, environmental protection, up-to-standard flame-retardant requirement, wide application prospect and important practical application value.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of new flame-retardant materials, and particularly relates to a chitosan derivative composite shell flame-retardant fabric and a preparation method and application thereof. BACKGROUND

[0002] As an indispensable part of people's daily life, the flammability of fabrics can lead to the occurrence of fire, posing a serious threat to human safety. In particular, in certain special occasions such as chemical plants, oil refineries, and hotels, meeting halls, etc., it is crucial for the fabrics used to have flame-retardant function. At the same time, the application of flame-retardant fabrics is not limited to specific industries or places, but is widely used in clothing, chemical industry, metallurgy, shipbuilding, fire fighting, national defense, etc. Flame-retardant fabrics can effectively prevent the spread of flames, reduce the spread and spread of fire, thereby reducing the harm of fire to personnel and property. In addition, flame-retardant fabrics can also reduce the release of toxic gases, further protecting human safety.

[0003] Li Xixi, He Liubin in (Flame Retardant and Wear Performance of Casein / Polyammonium Phosphate Finished Cotton Fabric, Printing and Dyeing Auxiliaries, 2021, 3: 54-56) used casein as the gas source (foaming agent) and polyammonium phosphate as the acid source (dehydrating agent and carbonization promoter) to prepare an intumescent flame-retardant cotton fabric by double-layer coating method. The results showed that casein / polyammonium phosphate was evenly covered on the surface of the cotton fabric. During the thermal degradation process, the coating reduced the decomposition temperature of the cotton fabric, promoted the decomposition of the cotton fabric into carbon and produced a foam barrier layer in advance, improved the flame-retardant performance of the cotton fabric, and the afterflame time was 4 s and the char length was 78 mm. After finishing with casein / polyammonium phosphate, the wear performance of the cotton fabric decreased.

[0004] Zhao Xiaoliang, Yang Kailei, Kong Lingyan, etc. in (Preparation and Performance of Environmentally Friendly Flame Retardant Fabric Finishing Agent, Printing and Dyeing, 2021, 5: 19-22) synthesized a flame-retardant monomer N,N-bis(2-hydroxyethyl) aminomethyl phosphonic acid diethyl ester (BHAPE) using formaldehyde, diethanolamine and diethyl phosphite as raw materials, and then prepared a flame-retardant waterborne polyurethane (WPU) using BHAPE, polyoxypropylene glycol (PPG2000), isophorone diisocyanate (IPDI), dimethylol propionic acid (DMPA), 1,4-butanediol (BDO) and trimethylolpropane (TMP) as main raw materials, and finished cotton fabric. The results showed that the BHAPE modified WPU finishing agent was successfully prepared; with the increase of the amount of BHAPE, the carbon residue of the modified WPU film and the finished cotton fabric increased, the limiting oxygen index of the cotton fabric increased from 17.8% to 20.6%, and the flame-retardant performance improved, but did not reach the level of difficult ignition.

[0005] From the above, the flame-retardant performance of the flame-retardant fabric is usually achieved by adding flame retardants which can form an insulating layer, decompose non-combustible gas, absorb heat, etc. at high temperature, thereby achieving the purpose of flame retardation. However, the halogen-containing flame retardants used to prepare the flame-retardant fabric are not environmentally friendly, the process is complex, the flame-retardant requirements are not up to standard, and the wearing comfort is reduced. SUMMARY

[0006] In view of the deficiencies of the prior art, the present application prepares a chitosan derivative flame retardant, and the method comprises the following steps:

[0007] 0.1-0.3mol of chitosan is dissolved in 500-1500ml of 1-5wt% acetic acid solution, 0.1-0.3mol of bis(4-carboxyphenyl)phenyl phosphine oxide is added, the temperature is raised to 70-95℃, and the temperature is kept for 3-5h. After the reaction is completed, the product is filtered, washed and dried.

[0008] Preferably, the molecular weight of the chitosan is 30000-80000, and the degree of deacetylation is ≥90; the purity is 99%.

[0009] Correspondingly, the present application also provides a fabric impregnated chitosan derivative flame retardant composite, which comprises: chitosan derivative flame retardant, shell, montmorillonite, graphene oxide, phytic acid, and phytate; the weight ratio of the chitosan derivative flame retardant to the shell is 1:0.05-0.5; the weight ratio of montmorillonite, graphene oxide, phytic acid, and phytate in the total weight of the composite is 1:0.05-1:0.5.

[0010] Preferably, the phytate is one or more of calcium magnesium phytate, iron phytate, and aluminum phytate.

[0011] Correspondingly, the present application provides a preparation method of the impregnated chitosan derivative flame retardant composite, which comprises:

[0012] The fiber fabric is immersed in the chitosan solution for 1-30min, dried, and dried at 50-80℃ for 2-6h; then, the fiber fabric is immersed in 1-5wt% chitosan derivative flame retardant composite suspension for 1-30min, dried, and dried at 50-80℃ for 2-6h; the process is repeated 1-20 times to obtain the chitosan derivative flame-retardant fabric.

[0013] Preferably, the chitosan solution is one or more of 1-5wt% hydrochloric acid, formic acid, lactic acid, malic acid, and acetic acid solution.

[0014] Preferably, the fabric impregnated chitosan derivative flame retardant composite solvent is one or more of water, acetic acid, methanol, ethanol, and isobutyl alcohol.

[0015] Correspondingly, the application also provides application of the chitosan derivative flame retardant complex in fabric impregnation, and the mass ratio of the chitosan derivative flame retardant complex to the fabric is 0.05-0.85:1.

[0016] Preferably, the fabric is a natural fiber fabric or a synthetic fiber fabric.

[0017] The technical scheme of the application has the following advantages compared with the prior art:

[0018] As shown in Figure 1 and Figure 2 , chitosan is a poly-cationic polysaccharide with amino groups, has film-forming property and anion adsorption property, and thus can obtain a functional coating film through layer-by-layer self-assembly with electronegative compounds. By using this property, a chitosan-based flame-retardant coating can be designed, which can be used in various low-dimensional polymer materials such as fibers and films. Through reaction of bis(p-carboxyphenyl)phenyl phosphine oxide with chitosan, acid source structures are introduced into the chitosan, and the positively charged amino groups are amidated, and the side chains are changed into electronegative carboxyl groups (the hydroxyl groups on the chitosan molecular chain also exhibit electronegativity after the amino groups are reacted), so that the charge reversal is realized. In addition, through the modification reaction, large side groups are introduced into the molecular chain of the chitosan, which can effectively destroy the crystalline structure of the chitosan, improve the solubility of the chitosan, and thus make the chitosan more conducive to the self-assembly reaction, and thus improve the washing stability. Through the layer-by-layer self-assembly of the chitosan and the modified chitosan in acetic acid solution on the cotton fabric, a firm interface flame-retardant coating can be effectively constructed. Since the molecular assembly is between chitosan and chitosan derivatives, the assembly effect is better than that of heterogeneous compounds, and has the advantages of good interlayer affinity and less interlayer peeling.

[0019] Compared with the current commercial flame-retardant coating mainly using pure organic solvents, this biomass water-based flame-retardant coating system is undoubtedly more environmentally friendly. When encountering a fire source, acid-catalyzed rapid charring can occur between the modified chitosan and the fibers, and a high-efficiency fireproof shielding layer can be formed on the surface of the fabric. Finally, chitosan itself is a commercial fabric finishing agent, which can improve the antibacterial property, comfort and antistatic property of the fabric, and will not damage the original hand feeling and appearance of the fabric, but will increase the comfort of the fabric to the human skin. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 is a schematic diagram of synthesis of the chitosan derivative flame retardant.

[0021] Figure 2 is a schematic diagram of construction of a modified chitosan-chitosan layer-by-layer self-assembly flame-retardant coating on the surface of a fabric.

[0022] Figure 3 is a picture comparison diagram of vertical burning of a pure nylon fabric in the prior art and a flame-retardant nylon fabric of the application. DETAILED DESCRIPTION

[0023] The preferred embodiments of the present application are further described in detail below with reference to the accompanying drawings:

[0024] Example 1

[0025] The preparation process of the chitosan derivative flame retardant is as follows: 0.1 mol of chitosan (molecular weight 30000, degree of deacetylation ≥90; purity 99%) is dissolved in 500 ml of 1 wt% hydrochloric acid, 0.1 mol of bis(4-carboxyphenyl) phenyl phosphine oxide (BCPPO) is added, the temperature is raised to 70°C, and the reaction is kept for 3 h. After the reaction is completed, the product is filtered, washed with methanol, and dried at 80°C for 6 hours.

[0026] Application:

[0027] (1) Fabric impregnated with chitosan derivative flame retardant composite (chitosan derivative flame retardant, shell, montmorillonite, graphene oxide, phytic acid, phytate), the weight ratio of chitosan derivative flame retardant to shell is 1:0.05, and the weight ratio of montmorillonite, graphene oxide, phytic acid, and calcium and magnesium salts to the total weight of the composite is 1:0.05, and the solvent is water; the mass ratio of the composite to the fabric is 0.05-0.85:1; the fabric is a natural fiber fabric (cotton / silk fiber fabric).

[0028] (2) Fabric impregnated with chitosan

[0029] Steps: the fiber fabric is immersed in a 5 wt% acetic acid solution for 1 min, dried, and dried at 50°C for 2 hours; then, the fiber fabric is immersed in a chitosan derivative flame retardant composite suspension (5 wt%) for 1 min, dried, and dried at 50°C for 2-6 hours; the process is repeated 1-20 times to obtain a chitosan derivative flame retardant fabric.

[0030] Example 2

[0031] The preparation process of the chitosan derivative flame retardant is as follows: 0.3 mol of chitosan (molecular weight 80000, degree of deacetylation ≥90; purity 99%) is dissolved in 1500 ml of 5 wt% formic acid solution, 0.3 mol of bis(4-carboxyphenyl) phenyl phosphine oxide (BCPPO) is added, the temperature is raised to 95°C, and the reaction is kept for 5 h. After the reaction is completed, the product is filtered, washed with ethanol, and dried at 80°C for 6 hours.

[0032] Application:

[0033] (1) Fabric impregnated chitosan derivative flame retardant composite (chitosan derivative flame retardant, shell, montmorillonite, graphene oxide, phytic acid, phytate), chitosan derivative flame retardant and shell 1:0.5, and the weight ratio of montmorillonite, graphene oxide, phytic acid, and acid iron salt to the total weight of the composite is 1:0.5, the solvent is acetic acid; The mass ratio of the composite to the fabric is 0.85:1; The fabric is a synthetic fiber fabric (polyamide / polyester / acrylic / spandex / vinylon).

[0034] (2) Fabric impregnated chitosan step: fiber fabric is immersed in 5wt% chitosan solution malic acid solution for 1-30min, controlled drying, and dried at 50-80℃ for 6 hours; then, the fiber fabric is immersed in chitosan derivative flame retardant composite suspension (1-5wt%) for 1-30min, controlled drying, and dried at 50-80℃ for 2-6 hours; repeat 1-20 times to obtain chitosan derivative flame retardant fabric.

[0035] The chitosan derivative flame retardant fabric obtained by the present application is tested and evaluated according to GB / T 5455-2014 standard. The test results are as follows:

[0036] Table 1 Vertical burning and limiting oxygen index test of flame-retardant polyamide fabric

[0037]

[0038] Table 1 is the vertical burning test result of flame-retardant polyamide fiber fabric with different impregnation times. It can be seen that with the increase of impregnation times, the LOI value of polyamide fabric increases. Compared with the impregnation 4 times, the LOI value of flame-retardant polyamide fabric reaches 33.5%, which belongs to difficult-to-burn material and can pass UL94 V-0 level.

[0039] Table 2 Vertical burning and limiting oxygen index test of flame-retardant polyamide fabric after different washing times

[0040]

[0041] The flame retardant performance change of impregnated 4 times flame-retardant polyamide fabric after different washing (washing machine washing) times is investigated. The research shows that after 30 times of washing, the flame retardant performance of flame-retardant polyamide fabric decreases slightly, but the decrease is not obvious, and it can still maintain V-0 flame retardant level. It has more durable adhesion than most commercial flame retardant finishing agents.

[0042] The preparation method of the present application has simple process, environmental protection, flame retardant requirement, wide application prospect and important practical application value.

[0043] The above is further detailed description of the present application in combination with specific preferred embodiments, and cannot be deemed as limitation of the specific implementation of the present application to these descriptions. For those skilled in the art to which the present application belongs, without departing from the concept of the present application, a number of simple deductions or substitutions can be made, and all should be deemed as falling within the protection scope of the present application.

Claims

1. A fabric-impregnated chitosan derivative flame retardant composite, characterized in that, include: The compound comprises chitosan derivative flame retardant, seashells, montmorillonite, graphene oxide, phytic acid, and phytate; by weight ratio, the chitosan derivative flame retardant to seashells is 1:0.05-0.5; the ratio of montmorillonite, graphene oxide, phytic acid, and phytate to the total weight of the compound is 0.05:1; the preparation method of the chitosan derivative flame retardant includes the following steps: Dissolve 0.1-0.3 mol of chitosan in 500-1500 ml of 1-5 wt% acetic acid solution. The chitosan has a molecular weight of 30,000-80,000, a degree of deacetylation ≥90%, and a purity of 99%. Add 0.1-0.3 mol of bis(4-carboxyphenyl)phenylphosphine oxide, heat to 70-95℃, and maintain the temperature for 3-5 hours. After the reaction is complete, filter the product, wash, and dry it. The bis(4-carboxyphenyl)phenylphosphine oxide undergoes an amidation reaction with the amino group of chitosan.

2. The fabric-impregnated chitosan derivative flame retardant composite as described in claim 1, characterized in that, The phytate is one or more of calcium magnesium phytate, iron phytate, and aluminum phytate.

3. A method for preparing a flame retardant composite impregnated with chitosan derivatives, characterized in that, include: The fiber fabric is immersed in chitosan solution for 1-30 minutes, drained, and dried at 50-80℃ for 2-6 hours. Then, the fiber fabric is impregnated with 1-5 wt% of the suspension of the chitosan derivative flame retardant composite as described in claim 1 for 1-30 min, drained, and dried at 50-80°C for 2-6 hours; this process is repeated 1-20 times to obtain the chitosan derivative flame retardant fabric.

4. A method for preparing the chitosan derivative flame retardant composite as described in claim 3, characterized in that, The chitosan solution is one or more of the following: 1-5 wt% hydrochloric acid, formic acid, lactic acid, malic acid, and acetic acid.

5. A method for preparing the chitosan derivative flame retardant composite as described in claim 3, characterized in that, The solvent for the fabric impregnation chitosan derivative flame retardant complex is one or more of water, acetic acid, methanol, ethanol and isobutanol.

6. The application of the chitosan derivative flame retardant composite as described in claim 1 in fabric impregnation, characterized in that, The mass ratio of the chitosan derivative flame retardant composite to the fabric is 0.05-0.85:

1.

7. The application as described in claim 6, characterized in that, The fabric is made of natural or synthetic fibers.

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