Flame-retardant cotton fabric based on biomass and preparation method thereof

Abstract

The preparation method comprises the following specific steps: firstly, respectively preparing a polyethyleneimine aqueous solution, a tannic acid aqueous solution and a phytic acid aqueous solution by using deionized water, then sequentially immersing the cotton fabric into the polyethyleneimine aqueous solution, the tannic acid aqueous solution, the polyethyleneimine aqueous solution and the phytic acid aqueous solution, finally immersing the cotton fabric into a metal salt solution, and carrying out vacuum drying to obtain the flame-retardant cotton fabric based on biomass. Washing and drying to obtain the flame-retardant cotton fabric. Compared with the prior art, the flame-retardant cotton fabric prepared on the basis of biomass has the advantages that raw materials are easy to obtain, the price is low, the process is simple and convenient, and formaldehyde is avoided, insoluble organic phosphonate is loaded on the surface of the cotton fabric through strong interaction among multiple layers of electrolytes and ion complexing, and the flame retardance and washing resistance of the cotton fabric are effectively improved; sustainable development is facilitated, and the method has important practical significance and wide market prospects.

Description

Technical Field

[0001] The invention relates to the technical field of flame retardant finishing of textiles, in particular to a biomass-based flame retardant cotton fabric and a preparation method thereof. Background Art

[0002] Cotton fabrics are widely used in clothing fabrics, household goods, car decoration and other fields due to their excellent moisture absorption and breathability, biocompatibility, hydrophilicity, soft and comfortable feel and many other advantages. However, the limiting oxygen index (LOI) of cotton fabrics is low, only about 18%, which makes them very easy to burn in the air and easily cause fire accidents. Therefore, flame retardant finishing of cotton fabrics can improve the flame retardancy of cotton fabrics and reduce the harm caused by burning, which is of great practical significance to expand the application scope of cotton fabrics.

[0003] The commonly used phosphorus-nitrogen flame retardants on the market are and Pyrovatex However, there is a lot of free formaldehyde, which is gradually released when people wear or use it, causing great harm to human health through respiratory and skin contact. Therefore, more and more researchers are committed to developing safe, environmentally friendly, halogen-free, and formaldehyde-free flame retardants for cotton fabrics.

[0004] The layer-by-layer self-assembly method (LBL) has the advantages of being environmentally friendly, simple preparation process and equipment, controllable thickness, low price, stable performance, little impact on the inherent properties of the substrate, and a wide range of applications. Reference 1 (Waste gelatin based layerby layer assembly for sustainable solution to cotton fabrics flame retardancy [J]. Progress in Organic Coatings, 2022, 163: 106688) extracted gelatin from leather and combined it with ammonium polyphosphate to load it onto cotton fabrics of different densities (100, 200, 400 g / m 2), when the number of deposition layers is 6, the peak heat release rate (PHRR) of the finished cotton fabric is reduced by 58.6%, 62.8%, and 40.5%, respectively, and the total heat release (THR) is reduced by 72.8%, 67.1%, and 14.7%, respectively. Reference 2 (Fire retardant and thermal degradation properties of cotton fabrics based on APTES and sodium phytate through layer-by-layer assembly [J]. Journal of Analytical and Applied Pyrolysis, 2017, 123: 216-223) 3-aminopropyltriethoxysilane (APTES) and sodium phytate are loaded onto cotton fabrics. When the number of assembly layers reaches 15, the PHRR and THR are reduced by 9.0% and 16.7%, respectively. Document 3 (Effect of chitosan on the fire retardancy and thermal degradation properties of coated cotton fabrics with sodium phytate and APTES by LBL assembly [J]. Journal of Analytical and Applied Pyrolysis, 2018, 135: 289-298) adds chitosan to the APTES / sodium phytate system on the basis of document 2 to prepare a flame retardant coating with odd layers of APTES / sodium phytate and even layers of chitosan / sodium phytate. When the number of layers reaches 15, the deposited cotton fabric can self-extinguish when leaving the flame, LOI increases to 29%, and PHRR and THR decrease by 82.1% and 66.1%, respectively. However, the current LBL method has the disadvantage of poor water washability, which limits its application on cotton fabrics.

[0005] In addition, the development of flame retardants using renewable natural resource biomass materials can avoid the environmental problems caused by the application of petrochemical products. These flame retardants have the advantages of being environmentally friendly, sustainable and cheap. Among them, phytic acid (PA) is a common non-toxic natural organic phosphorus-containing biomass material, mainly found in the seeds and rhizomes of plants, and tannic acid (TA) is usually found in the bark and fruits of plants. Literature 4 (Bio-Based Flame-Retardant Coatings Based on the Synergistic Combination of Tannic Acid and Phytic Acid for Nylon-Cotton Blends [J]. ACS Applied Materials & Interfaces, 2021, 13 (51), 61620-61628) TA and PA are loaded onto nylon / cotton fabrics through hydrogen bonds. The THR and PHRR of the treated fabrics are reduced by 51.4% and 44.9% respectively compared with the untreated fabrics, indicating that PA and TA have excellent flame retardant properties.

[0006] Therefore, it is of great significance to study a preparation method of biomass-based flame-retardant cotton fabric to improve the flame retardant effect and washability. Summary of the invention

[0007] The purpose of the present invention is to provide a biomass-based flame-retardant cotton fabric and a preparation method thereof in order to overcome the defects of the above-mentioned prior art, and to provide an effective solution to the problem of formaldehyde residue and subsequent formaldehyde release in the use of existing flame-retardant cotton fabrics.

[0008] During the process of conception, the applicant believed that: the present invention uses polyethyleneimine (PEI), TA, and PA to be deposited on cotton fabric, and then undergoes a complex reaction with a metal salt solution to construct a biomass-based flame retardant system; the strong interaction between the multilayer electrolytes and the ion complexation load insoluble organic phosphonates on the surface of the cotton fabric, effectively improving the flame retardancy and water washability of the cotton fabric.

[0009] The purpose of the present invention can be achieved by the following technical solutions:

[0010] In one aspect, the present invention provides a method for preparing a biomass-based flame-retardant cotton fabric, comprising the following steps:

[0011] S1. Prepare polyethyleneimine, tannic acid and phytic acid aqueous solutions respectively with deionized water;

[0012] S2, immersing the cotton fabric in the aqueous solutions of polyethyleneimine, tannic acid, polyethyleneimine and phytic acid prepared in S1 in sequence;

[0013] S3, immersing the cotton fabric in the metal salt solution, then taking out the cotton fabric, washing it with water, and drying it to obtain the flame-retardant cotton fabric.

[0014] Furthermore, in S1, the concentrations of the polyethyleneimine, tannic acid and phytic acid aqueous solutions are all between 1 and 6 wt%.

[0015] Further preferably, in S1, the concentration ratio of the polyethyleneimine, tannic acid and phytic acid aqueous solutions is 3:2:6.

[0016] Furthermore, in S2, the cotton fabric is immersed for 1 to 5 minutes each time.

[0017] Furthermore, in S3, the cotton fabric is immersed in the metal salt solution for 1 minute, and precipitation is immediately generated when the cotton fabric is immersed in the metal salt solution.

[0018] Furthermore, in S3, the concentration of the metal salt solution is 0.05-0.3M.

[0019] Furthermore, the metal salt is ferric nitrate, copper nitrate or zinc sulfate.

[0020] Furthermore, in S3, the drying temperature is 80°C and the drying time is 10 minutes; if the drying temperature is too high, the acidic phytic acid will affect the strength of the cotton fabric, directly affecting the durability and reliability of the fabric.

[0021] On the other hand, the present invention also provides a biomass-based flame-retardant cotton fabric obtained by the above-mentioned preparation method. The flame-retardant cotton fabric does not produce formaldehyde during the preparation process, has a soft hand feel, and after 10 to 20 washes, the formaldehyde-free, water-resistant, flame-retardant cotton fabric can still pass the vertical burning test, and the limiting oxygen index is as high as 28.5%, still showing good flame retardant properties.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] (1) The present invention provides a method for preparing a washable flame-retardant cotton fabric, which uses PEI, TA, and PA to deposit on the cotton fabric, and then reacts with a metal salt solution to construct a biomass-based flame retardant system. Among them, TA mainly exists in the seeds and rhizomes of plants, is an environmentally friendly, non-toxic, and easily available organic phosphoric acid, has a phosphorus content of up to 28.0%, and can chelate metal ions; PA usually exists in the bark and fruit of plants, has high carbonization and good free radical scavenging ability.

[0024] (2) The raw materials involved in the present invention are easily available, and no volatile organic solvents are used, which is friendly to the environment and the human body. At the same time, the preparation process is simple and easy to realize industrial production. No formaldehyde is released during the flame retardant finishing process of cotton fabrics and during the use of flame retardant fabrics. In addition, the insoluble organic phosphonic acid metal salt on the surface of the cotton fabric enables the cotton fabric to have not only excellent flame retardant properties, but also good water wash resistance.

[0025] (3) Compared with the corresponding untreated fabric, the flame-retardant cotton fabric provided by the present invention still exhibits good flame-retardant properties after multiple washings, can still pass the vertical burning test, and the LOI can reach 28.5%. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic diagram of the vertical burning test results of cotton fabrics after different treatments of the present invention.

[0027] (0) Comparative Example 1, (1) Comparative Example 2, (2) Comparative Example 3, (3) Comparative Example 4, (4) Comparative Example 5, (5) Example 1, (6) Comparative Example 6, (7) Example 2, (8) Example 3, (9) Comparative Example 7, (10) Example 4, (11) Example 5, (12) Comparative Example 8, (13) Example 6, (14) Example 7, (15) Example 8. DETAILED DESCRIPTION

[0028] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. Any features such as preparation means, materials, structures or composition ratios not clearly described in this technical solution are regarded as common technical features disclosed in the prior art.

[0029] The limiting oxygen index (LOI) of the flame-retardant cotton fabric prepared in the following examples is tested according to (GB / T5454-2013 "Textile Combustion Performance Experiment Oxygen Index Method"); the vertical burning damage length, afterflaming time, and smoldering time are measured on a vertical burning tester, using (GB / T 5455-2014 "Determination of Vertical Direction Damage Length Smoldering and Afterflaming Time of Textile Combustion Performance") as the standard method for testing the vertical burning performance of cotton fabrics; the washing method refers to (GB / T 8629-2017 "Household Washing and Drying Procedure for Textile Testing").

[0030] The size of the cotton fabric sample is 30*8cm.

[0031] Comparative Example 1

[0032] Untreated cotton fabric: Afterflame time 9.5s, smoldering time 18.3s, complete destruction, LOI 17.8%.

[0033] Comparative Example 2

[0034] This embodiment provides a method for preparing a biomass-based flame-retardant cotton fabric, and the specific preparation steps are as follows:

[0035] S1. Prepare 3% PEI, 2% TA, and 6% PA aqueous solutions respectively with deionized water;

[0036] S2. The cotton fabric was immersed in the PEI, TA, PEI, and PA aqueous solutions prepared in S1 for 1 min in sequence, and then the cotton fabric was taken out, washed with water, and dried at 80° C. for 10 min to obtain a flame retardant cotton fabric.

[0037] The flame retardant cotton fabric obtained had an afterflaming time of 0 s, a smoldering time of 0 s, was completely destroyed, and had a LOI of 24.8%.

[0038] Comparative Example 3

[0039] This embodiment provides a method for preparing a biomass-based flame-retardant cotton fabric, and the specific preparation steps are as follows:

[0040] S1. Prepare 3% PEI, 2% TA, and 6% PA aqueous solutions respectively with deionized water;

[0041] S2. The cotton fabric is immersed in the PEI, TA, PEI, and PA aqueous solutions prepared in S1 for 3 minutes in sequence, and then the cotton fabric is taken out, washed with water, and dried at 80° C. for 10 minutes to obtain a flame retardant cotton fabric.

[0042] The obtained flame retardant cotton fabric has an afterflame time of 0s, a smoldering time of 0s, a damaged length of 3.0cm, and an LOI of 30.5%, which can meet the Class 1 standard for fabrics in GB 20286-2006 "Combustion performance requirements and marking of flame retardant products and components in public places" (Flame retardant Class 1: damaged charcoal length ≤150mm, afterflame time ≤5s, smoldering time ≤5s).

[0043] Comparative Example 4

[0044] This embodiment provides a method for preparing a biomass-based flame-retardant cotton fabric, and the specific preparation steps are as follows:

[0045] S1. Prepare 3% PEI, 2% TA, and 6% PA aqueous solutions respectively with deionized water;

[0046] S2. The cotton fabric is immersed in the PEI, TA, PEI, and PA aqueous solutions prepared in S1 for 5 minutes in sequence, and then the cotton fabric is taken out, washed with water, and dried at 80° C. for 10 minutes to obtain a flame retardant cotton fabric.

[0047] The obtained flame retardant cotton fabric has an afterflame time of 0s, a smoldering time of 0s, a damaged length of 3.2cm, and an LOI of 30.4%, which can meet the Class 1 standard for fabrics in GB 20286-2006 "Combustion performance requirements and marking of flame retardant products and components in public places" (Flame retardant Class 1: damaged charcoal length ≤150mm, afterflame time ≤5s, smoldering time ≤5s).

[0048] Comparative Example 5

[0049] This embodiment provides a method for preparing a biomass-based flame-retardant cotton fabric, and the specific preparation steps are as follows:

[0050] S1. Prepare 3% PEI, 2% TA, and 6% PA aqueous solutions respectively with deionized water;

[0051] S2. The cotton fabric is immersed in the PEI, TA, PEI, and PA aqueous solutions prepared in S1 for 3 minutes in sequence, and then the cotton fabric is taken out, washed with water, and dried at 80° C. for 10 minutes to obtain a flame retardant cotton fabric.

[0052] The flame retardant cotton fabric obtained after 10 washings had an afterflaming time of 4.1 s, a smoldering time of 0 s, was completely destroyed, and an LOI of 22.4%.

[0053] Example 1

[0054] This embodiment provides a method for preparing a biomass-based flame-retardant cotton fabric, and the specific preparation steps are as follows:

[0055] S1. Prepare 3% PEI, 2% TA, and 6% PA aqueous solutions respectively with deionized water;

[0056] S2, immersing the cotton fabric in the PEI, TA, PEI, and PA aqueous solutions prepared in S1 for 3 min in sequence;

[0057] S3. Immerse the cotton fabric in a 0.2 M ferric nitrate solution for 1 min, then take out the cotton fabric, wash it with water, and dry it at 80° C. for 10 min to obtain a flame retardant cotton fabric.

[0058] The obtained flame retardant cotton fabric has an afterflame time of 0s, a smoldering time of 0s, a damaged length of 4.1cm, and an LOI of 30.1%, which can meet the Class 1 fabric standard of GB 20286-2006 "Combustion performance requirements and marking of flame retardant products and components in public places" (Flame retardant Class 1: damaged charcoal length ≤150mm, afterflame time ≤5s, smoldering time ≤5s).

[0059] Comparative Example 6

[0060] This embodiment provides a method for preparing a biomass-based flame-retardant cotton fabric, and the specific preparation steps are as follows:

[0061] S1. Prepare 3% PEI, 2% TA, and 6% PA aqueous solutions respectively with deionized water;

[0062] S2, immersing the cotton fabric in the PEI, TA, PEI, and PA aqueous solutions prepared in S1 for 3 min in sequence;

[0063] S3. Immerse the cotton fabric in a 0.2 M ferric nitrate solution for 1 min, then take out the cotton fabric, wash it with water, and dry it at 80° C. for 10 min to obtain a flame retardant cotton fabric.

[0064] The flame retardant cotton fabric obtained after 10 times of water washing has a subsequent burning time of 3.6s, a smoldering time of 0s, is completely destroyed, and the LOI is 23.9%.

[0065] Example 2

[0066] This embodiment provides a method for preparing a biomass-based flame-retardant cotton fabric, and the specific preparation steps are as follows:

[0067] S1. Prepare 3% PEI, 2% TA, and 6% PA aqueous solutions respectively with deionized water;

[0068] S2, immersing the cotton fabric in the PEI, TA, PEI, and PA aqueous solutions prepared in S1 for 3 min in sequence;

[0069] S3. Immerse the cotton fabric in a 0.2 M copper nitrate solution for 1 min, then take out the cotton fabric, wash it with water, and dry it at 80° C. for 10 min to obtain a flame retardant cotton fabric.

[0070] The obtained flame retardant cotton fabric has an afterflame time of 0s, a smoldering time of 0s, a damaged length of 2.3cm, and an LOI of 31.7%, which can meet the Class 1 fabric standard of GB 20286-2006 "Combustion performance requirements and marking of flame retardant products and components in public places" (Flame retardant Class 1: damaged charcoal length ≤150mm, afterflame time ≤5s, smoldering time ≤5s).

[0071] Example 3

[0072] This embodiment provides a method for preparing a biomass-based flame-retardant cotton fabric, and the specific preparation steps are as follows:

[0073] S1. Prepare 3% PEI, 2% TA, and 6% PA aqueous solutions respectively with deionized water;

[0074] S2, immersing the cotton fabric in the PEI, TA, PEI, and PA aqueous solutions prepared in S1 for 3 min in sequence;

[0075] S3. Immerse the cotton fabric in a 0.2 M copper nitrate solution for 1 min, then take out the cotton fabric, wash it with water, and dry it at 80° C. for 10 min to obtain a flame retardant cotton fabric.

[0076] After 10 times of water washing, the obtained flame retardant cotton fabric has a continuing burning time of 0s, a smoldering time of 0s, a damaged length of 8.4cm, and a LOI of 27.2%, which can meet the Class 1 standard of fabrics in GB 20286-2006 "Combustion performance requirements and markings for flame retardant products and components in public places" (Flame retardant Class 1: damaged charcoal length ≤150mm, continuing burning time ≤5s, smoldering time ≤5s).

[0077] Comparative Example 7

[0078] This embodiment provides a method for preparing a biomass-based flame-retardant cotton fabric, and the specific preparation steps are as follows:

[0079] S1. Prepare 3% PEI, 2% TA, and 6% PA aqueous solutions respectively with deionized water;

[0080] S2, immersing the cotton fabric in the PEI, TA, PEI, and PA aqueous solutions prepared in S1 for 3 min in sequence;

[0081] S3. Immerse the cotton fabric in a 0.2 M copper nitrate solution for 1 min, then take out the cotton fabric, wash it with water, and dry it at 80° C. for 10 min to obtain a flame retardant cotton fabric.

[0082] The flame retardant cotton fabric obtained after 20 times of water washing has a subsequent burning time of 2.0s, a smoldering time of 0s, is completely destroyed, and the LOI is 24.6%.

[0083] Example 4

[0084] This embodiment provides a method for preparing a biomass-based flame-retardant cotton fabric, and the specific preparation steps are as follows:

[0085] S1. Prepare 3% PEI, 2% TA, and 6% PA aqueous solutions respectively with deionized water;

[0086] S2, immersing the cotton fabric in the PEI, TA, PEI, and PA aqueous solutions prepared in S1 for 3 min in sequence;

[0087] S3. Immerse the cotton fabric in a 0.2 M zinc sulfate solution for 1 min, then take out the cotton fabric, wash it with water, and dry it at 80° C. for 10 min to obtain a flame retardant cotton fabric.

[0088] The obtained flame retardant cotton fabric has an afterflame time of 0s, a smoldering time of 0s, a damaged length of 2.6cm, and an LOI of 31.3%, which can meet the Class 1 standard for fabrics in GB 20286-2006 "Combustion performance requirements and markings for flame retardant products and components in public places" (Flame retardant Class 1: damaged charcoal length ≤150mm, afterflame time ≤5s, smoldering time ≤5s).

[0089] Example 5

[0090] This embodiment provides a method for preparing a biomass-based flame-retardant cotton fabric, and the specific preparation steps are as follows:

[0091] S1. Prepare 3% PEI, 2% TA, and 6% PA aqueous solutions respectively with deionized water;

[0092] S2, immersing the cotton fabric in the PEI, TA, PEI, and PA aqueous solutions prepared in S1 for 3 min in sequence;

[0093] S3. Immerse the cotton fabric in a 0.3 M zinc sulfate solution for 1 min, then take out the cotton fabric, wash it with water, and dry it at 80° C. for 10 min to obtain a flame retardant cotton fabric.

[0094] The obtained flame retardant cotton fabric has an afterflame time of 0s, a smoldering time of 0s, a damaged length of 4.3cm, and an LOI of 30.3%, which can meet the Class 1 standard for fabrics in GB 20286-2006 "Combustion performance requirements and marking of flame retardant products and components in public places" (Flame retardant Class 1: damaged charcoal length ≤150mm, afterflame time ≤5s, smoldering time ≤5s).

[0095] Comparative Example 8

[0096] This embodiment provides a method for preparing a biomass-based flame-retardant cotton fabric, and the specific preparation steps are as follows:

[0097] S1. Prepare 3% PEI, 2% TA, and 6% PA aqueous solutions respectively with deionized water;

[0098] S2, immersing the cotton fabric in the PEI, TA, PEI, and PA aqueous solutions prepared in S1 for 3 min in sequence;

[0099] S3. Immerse the cotton fabric in a 0.05 M zinc sulfate solution for 1 min, then take out the cotton fabric, wash it with water, and dry it at 80° C. for 10 min to obtain a flame retardant cotton fabric.

[0100] The flame retardant cotton fabric obtained after 10 times of water washing has a subsequent burning time of 0 s, a smoldering time of 0 s, is completely destroyed, and has a LOI of 23.5%.

[0101] Example 6

[0102] This embodiment provides a method for preparing a biomass-based flame-retardant cotton fabric, and the specific preparation steps are as follows:

[0103] S1. Prepare 3% PEI, 2% TA, and 6% PA aqueous solutions respectively with deionized water;

[0104] S2, immersing the cotton fabric in the PEI, TA, PEI, and PA aqueous solutions prepared in S1 for 3 min in sequence;

[0105] S3. Immerse the cotton fabric in a 0.1 M zinc sulfate solution for 1 min, then take out the cotton fabric, wash it with water, and dry it at 80° C. for 10 min to obtain a flame retardant cotton fabric.

[0106] The flame retardant cotton fabric obtained after 10 washings has a post-flaming time of 0s, a smoldering time of 0s, a damaged length of 8.9cm, and an LOI of 27.4%, which can meet the Class 1 standard for fabrics in GB 20286-2006 "Combustion performance requirements and markings for flame retardant products and components in public places" (Flame retardant Class 1: damaged charcoal length ≤150mm, post-flaming time ≤5s, smoldering time ≤5s).

[0107] Example 7

[0108] This embodiment provides a method for preparing a biomass-based flame-retardant cotton fabric, and the specific preparation steps are as follows:

[0109] S1. Prepare 3% PEI, 2% TA, and 6% PA aqueous solutions respectively with deionized water;

[0110] S2, immersing the cotton fabric in the PEI, TA, PEI, and PA aqueous solutions prepared in S1 for 3 min in sequence;

[0111] S3. Immerse the cotton fabric in a 0.2 M zinc sulfate solution for 1 min, then take out the cotton fabric, wash it with water, and dry it at 80° C. for 10 min to obtain a flame retardant cotton fabric.

[0112] The flame retardant cotton fabric obtained after 10 washings has a post-flaming time of 0s, a smoldering time of 0s, a damaged length of 5.0cm, and an LOI of 28.5%, which can meet the Class 1 fabric standard of GB 20286-2006 "Combustion performance requirements and markings for flame retardant products and components in public places" (Flame retardant Class 1: damaged charcoal length ≤150mm, post-flaming time ≤5s, smoldering time ≤5s).

[0113] Example 8

[0114] This embodiment provides a method for preparing a biomass-based flame-retardant cotton fabric, and the specific preparation steps are as follows:

[0115] S1. Prepare 3% PEI, 2% TA, and 6% PA aqueous solutions respectively with deionized water;

[0116] S2, immersing the cotton fabric in the PEI, TA, PEI, and PA aqueous solutions prepared in S1 for 3 min in sequence;

[0117] S3. Immerse the cotton fabric in a 0.2 M zinc sulfate solution for 1 min, then take out the cotton fabric, wash it with water, and dry it at 80° C. for 10 min to obtain a flame retardant cotton fabric.

[0118] After 20 times of water washing, the obtained flame-retardant cotton fabric has a post-flaming time of 0s, a smoldering time of 0s, a damaged length of 10.2cm, and a LOI of 26.1%, which can meet the Class 1 standard of fabrics in GB 20286-2006 "Combustion performance requirements and markings for flame-retardant products and components in public places" (Flame retardant Class 1: damaged charcoal length ≤150mm, post-flaming time ≤5s, smoldering time ≤5s).

[0119] It should be noted that the concentration of PEI, TA, and PA aqueous solutions and the order of immersion have an impact on the reaction results. Changing the concentration of PEI, TA, and PA aqueous solutions or the order of immersion of cotton fabrics will cause the fabric to be completely destroyed when burned; and cotton fabrics only immersed in metal salt solutions will also be completely destroyed when burned.

[0120] Table 1 shows the afterflaming time, smoldering time, damaged length and LOI test results of the flame-retardant cotton fabrics prepared in Examples 1-15 and the untreated cotton fabric in Comparative Example 1 for vertical combustion.

[0121] From the data in Table 1, it can be seen that cotton fabrics that have not been impregnated with metal salt solutions are not resistant to washing, and the flame retardancy and washability of cotton fabrics are related to the type of metal salt and the concentration of the metal salt solution. Among them, zinc sulfate is better than iron nitrate and copper nitrate. The higher the concentration of the metal salt solution, the better the flame retardancy and washability of the cotton fabric.

[0122] Table 1 Vertical combustion and LOI results in Examples 1-15 and Comparative Example 1

[0123]

[0124] The above description of the embodiments is to facilitate the understanding and use of the invention by those skilled in the art. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative work. Therefore, the present invention is not limited to the above embodiments, and improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the present invention should be within the scope of protection of the present invention.

Claims

1. A method for preparing a flame-retardant cotton fabric based on biomass, characterized in that: The following steps are involved: S1, preparing polyethyleneimine, tannic acid and phytic acid aqueous solutions respectively; S2, immersing the cotton fabric in the aqueous solutions of polyethyleneimine, tannic acid, polyethyleneimine and phytic acid prepared in S1 in sequence; S3, immersing the cotton fabric in the metal salt solution, then taking out the cotton fabric, washing it with water, and drying it to obtain the flame-retardant cotton fabric.

2. The method for preparing a biomass-based flame-retardant cotton fabric according to claim 1, characterized in that: In S1, the concentrations of the polyethyleneimine, tannic acid and phytic acid aqueous solutions are all between 1 and 6 wt%.

3. The method for preparing a biomass-based flame-retardant cotton fabric according to claim 1, characterized in that: In S1, the concentration ratio of the polyethyleneimine, tannic acid and phytic acid aqueous solutions is 3:2:

6.

4. The method for preparing a biomass-based flame-retardant cotton fabric according to claim 1, characterized in that: In S2, the cotton fabric is immersed for 1 to 5 minutes each time.

5. The method for preparing a biomass-based flame-retardant cotton fabric according to claim 1, characterized in that: In S3, the cotton fabric is immersed in the metal salt solution for 1 min.

6. The method for preparing a biomass-based flame-retardant cotton fabric according to claim 1, characterized in that: In S3, the concentration of the metal salt solution is 0.05-0.3M.

7. The method for preparing a biomass-based flame-retardant cotton fabric according to claim 6, characterized in that: The metal salt is ferric nitrate, copper nitrate or zinc sulfate.

8. The method for preparing a biomass-based flame-retardant cotton fabric according to claim 1, characterized in that: In S3, the drying temperature is 80°C.

9. The method for preparing a biomass-based flame-retardant cotton fabric according to claim 1, characterized in that: In S3, the drying time is 10 minutes.

10. A biomass-based flame-retardant cotton fabric prepared by the method according to any one of claims 1 to 9.

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