Flame-retardant silk fabric and preparation method thereof

Abstract

The invention discloses a preparation method of a flame-retardant silk fabric, which comprises the following steps: uniformly mixing a gallic acid aqueous solution and a polyethyleneimine aqueous solution, and adding alkali liquor to adjust the pH value to be alkaline to obtain finishing liquor; carrying out first treatment on the degummed silk fabric by adopting the finishing liquid to obtain the silk fabric treated by the finishing liquid; preparing a multivalent metal salt solution, and carrying out secondary treatment on the silk fabric treated by the finishing liquid by adopting the multivalent metal salt solution to obtain the silk fabric subjected to flame-retardant finishing; and drying the silk fabric subjected to flame-retardant finishing to obtain the flame-retardant silk fabric. According to the preparation method, a self-crosslinking network of PEI and GA is formed on the surface of the fabric and chelated with metal ions (Me), the PEI-GA / Me composite coating silk fabric is prepared, the environmental protection problem of a flame retardant and the durability problem of a natural molecular flame retardant are solved, and the antibacterial function is provided for the fabric while the flame retardant property is met.

Description

Technical Field

[0001] The invention belongs to the technical field of flame retardancy and textile functional finishing, and particularly relates to a method for preparing a durable flame retardant silk fabric and the flame retardant silk fabric prepared by the preparation method. Background Art

[0002] Silk is widely used in high-end clothing and home textiles due to its excellent breathability, skin-friendliness and moisture absorption, as well as its smooth and soft properties. However, ordinary silk is flammable and burns quickly, threatening the safety of users. The flammability of silk itself limits its application potential and safety. Flame-retardant silk fabrics can enhance fire safety while maintaining their beauty, making them ideal for luxury home textiles and high-end fashion. In addition, since the protein structure of silk provides a favorable environment for bacterial growth, its antibacterial properties are poor, which further highlights the need for multifunctional silk fabrics that integrate flame retardancy and other functions.

[0003] Halogen-containing compounds were once widely used for their excellent flame retardant properties, but were eventually restricted or banned due to their toxicity, bioaccumulation and environmental pollution. Phosphorus-based flame retardants commonly used on the market may release formaldehyde during use. In addition, the accumulation of phosphorus in the natural environment may also cause eutrophication of lakes and other water bodies, which not only destroys aquatic ecosystems but also poses a long-term threat to the entire environment. Due to these serious problems, the field of textile flame retardants is actively exploring new alternatives, and compounds that are unrelated to phosphorus and halogens have become the mainstream trend of future development. This shift aims to balance the flame retardant properties of textiles with the needs of environmental protection and human health, and to promote the textile industry to develop in a greener and safer direction.

[0004] In recent years, natural compounds and their derivatives have become an important research hotspot as environmentally friendly textile flame retardants. Biomolecules, such as biomass-based proteins and deoxyribonucleic acid (DNA), have been used as sustainable flame retardant coatings. Natural polyphenols are the most abundant and widely distributed bioactive molecules in plants, with the advantages of low cost, non-toxicity, safety and renewability. For example, by adsorbing bio-based flavonoids and then mordanting with metal salts, the resulting composite exhibits flame retardant properties on silk fabrics [Flavonoids-metal salts combination: A facile and efficient route for enhancing the flame retardancy of silk, Ind. Crops Prod. 130 (2019) 580-591.]. However, due to the non-covalent deposition of biomacromolecules on the surface, the treated fabrics perform poorly in terms of washing resistance.

[0005] Gallic acid (GA) is a widely existing natural polyphenol with a phenolic hydroxyl structure, which gives it multiple functions such as antibacterial, antioxidant, antiviral and anti-inflammatory. The low cost and high reactivity of gallic acid make it widely used in the functional modification of materials. In addition, GA also has good flame retardancy and cross-linking properties. For example, two modified gallic acids (GAP and GAN) were prepared as reactive flame retardants and cross-linkers for the production of flame-retardant polyurethane elastomers (PUE). The introduction of GAP and GAN significantly improved the coke yield and LOI value of PUE [Modified gallic acids as both reactive flame retardants and cross-linkers for the fabrication of flame-retardantpolyurethane elastomers, ChemistrySelect 8(39)(2023)e202302496].

[0006] The amino-quinone network (AQN) coating method is a new development in mussel-inspired chemistry in recent years. This method forms a self-crosslinking coating through the Michael addition / Schiff base reaction between polyamine compounds and quinone compounds generated by the oxidation of polyphenol compounds. The advantages of the AQN coating method include a one-step reaction process, mild conditions and durability of the resulting coating. Polyethyleneimine (PEI) is rich in reactive primary amino groups that can react with GA to form a self-crosslinking network. The AQN system can remove the hydration layer on the surface of the material and obtain strong adhesion. In addition, studies have shown that nitrogen-modified polyphenols have a good effect in reducing the peak heat release rate of cellulose fibers. This supports the application of AQN in flame retardant textiles.

[0007] For example, patent CN201910565152.9, a method for preparing formaldehyde-free, water-resistant and flame-retardant fabrics, uses fabrics fixed with natural polyphenol compounds to be boiled in a metal salt solution to obtain formaldehyde-free, water-resistant and flame-retardant fabrics. However, during the preparation process, the fabric after the deposition of natural polyphenol compounds needs to be boiled in a fixing agent solution, and the fixing agent solution is at least one of tartar emetic solution, chitosan solution, color fixer Y solution, and water-soluble polyurethane color fixer solution. Among them, the color fixer Y has a very high free formaldehyde content; the other three color fixers all improve the flame retardancy and durability of the fabric by forming a film on the surface of the fabric, which will affect the feel of the fabric.

[0008] Another example is patent CN201811270759.6, which discloses a flame-retardant silk and its preparation method and application. Silk is immersed in tannic acid and metal salt solution to prepare flame-retardant silk fabric. However, the limiting oxygen index of unwashed silk fabric is only 27.5%, and the effect needs to be improved. In addition, the processing temperature of this method is relatively high, and batch preparation has not been achieved.

[0009] The disclosure of the above background technology content is only used to assist in understanding the inventive concept and technical solution of the present invention. It does not necessarily belong to the prior art of this patent application. In the absence of clear evidence that the above content has been disclosed before the filing date of this patent application, the above background technology should not be used to evaluate the novelty and creativity of the present application. Summary of the invention

[0010] In view of this, in order to overcome the defects of the prior art, the object of the present invention is to provide an improved flame retardant silk fabric with better flame retardant durability.

[0011] In order to achieve the above object, the present invention adopts the following technical solutions:

[0012] A method for preparing a flame retardant silk fabric comprises the following steps:

[0013] The gallic acid aqueous solution and the polyethyleneimine aqueous solution are mixed uniformly, and an alkali solution is added to adjust the pH value to alkaline to obtain a finishing solution;

[0014] The degummed silk fabric is treated for the first time with the finishing liquid to obtain the silk fabric treated with the finishing liquid;

[0015] Preparing a multivalent metal salt solution, and using the multivalent metal salt solution to perform a second treatment on the silk fabric treated with the finishing liquid to obtain a flame-retardant finished silk fabric;

[0016] The flame-retardant finished silk fabric is dried to obtain the flame-retardant silk fabric.

[0017] According to some preferred embodiments of the present invention, the gallic acid aqueous solution is prepared by the following method: mixing gallic acid with deionized water at 40-60° C. to completely dissolve the gallic acid in the deionized water to obtain a gallic acid aqueous solution with a concentration of 5 g / L to 10 g / L.

[0018] According to some preferred embodiments of the present invention, the polyethyleneimine aqueous solution is prepared by the following method: polyethyleneimine is mixed with deionized water at 30-50° C. to completely dissolve the polyethyleneimine in the deionized water to obtain a polyethyleneimine aqueous solution with a concentration of 5 g / L to 50 g / L.

[0019] According to some preferred embodiments of the present invention, the weight average molecular weight of the polyethyleneimine is 500-5000.

[0020] According to some preferred embodiments of the present invention, the volume ratio between the gallic acid aqueous solution and the polyethyleneimine aqueous solution is 1:2 to 1:4.

[0021] According to some preferred implementation aspects of the present invention, the alkali solution is a sodium hydroxide solution with a concentration of 5 g / L to 20 g / L, and the pH of the finishing solution is 8 to 10.

[0022] According to some preferred embodiments of the present invention, the multivalent metal salt is one or more selected from ferrous sulfate, ferric sulfate, aluminum sulfate, and titanium sulfate; and the concentration of the multivalent metal salt solution is 5 g / L to 50 g / L.

[0023] According to some preferred implementation aspects of the present invention, the first treatment is: adding the finishing liquid into the dyeing tank of the jigger, heating it to 35°C to 50°C, winding the degummed silk fabric on the cloth winding roller through the dyeing tank, and obtaining the silk fabric treated with the finishing liquid after jigger dyeing; the bath ratio during jigger dyeing is 1:3 to 1:5.

[0024] According to some preferred implementation aspects of the present invention, the second treatment is: adding a polyvalent metal salt aqueous solution into the dyeing tank of a jigger, heating it to 40°C to 60°C, moving the silk fabric treated with the finishing liquid into the jigger, and obtaining a flame-retardant finished silk fabric after jigger dyeing; the bath ratio during jigger dyeing is 1:3 to 1:5.

[0025] According to some preferred implementation aspects of the present invention, the drying temperature is 50-90° C. and the drying time is 20-40 minutes.

[0026] In some embodiments of the present invention, a method for preparing a durable flame retardant silk fabric, using silk fabric as a substrate, comprises the following steps:

[0027] (1) Preparation of finishing liquid

[0028] Gallic acid is mixed with deionized water at 40-60° C. to completely dissolve the gallic acid in the deionized water, thereby obtaining a gallic acid aqueous solution with a concentration of 5 g / L-10 g / L.

[0029] The polyethyleneimine is mixed with deionized water at 30-50° C. to completely dissolve the polyethyleneimine in the deionized water, thereby obtaining a polyethyleneimine aqueous solution with a concentration of 5 g / L-50 g / L.

[0030] The gallic acid aqueous solution and the polyethyleneimine aqueous solution are uniformly mixed in a volume ratio of 1:2 to 1:4, and an alkali solution is added to adjust the pH value to 8 to 10 to obtain a finishing solution.

[0031] (2) Fabric finishing

[0032] Add the finishing liquid into the dyeing tank of the jigger, raise the temperature to 35℃~50℃, pass the degummed silk fabric through the dyeing tank at a bath ratio of 1:3~1:5 and wind it on the cloth winding roller, the jigger speed is 5~10 m / min, reciprocate 2 times, wash once, and exit the machine to obtain the silk fabric treated with the finishing liquid.

[0033] (3) Preparation of polyvalent metal salt solution

[0034] In another jigger, a polyvalent metal salt aqueous solution with a concentration of 5 g / L to 50 g / L is prepared and heated to 40° C. to 60° C. The polyvalent metal salt is one or more selected from ferrous sulfate, ferric sulfate, aluminum sulfate, and titanium sulfate.

[0035] (4) Treatment of metal salts

[0036] The silk fabric treated with the finishing liquid is moved to the jigger of the above-mentioned multivalent metal salt solution, the rotation speed of the jigger is 5-10 m / min, the bath ratio during jigger dyeing is 1:3-1:5, after 2 reciprocating passes, 3 water washes, and the silk fabric with flame retardant finishing is obtained.

[0037] (5) Drying

[0038] The flame-retardant finished silk fabric is moved to a drying room and dried at 50-90° C. for 20-40 minutes to obtain a durable flame-retardant silk fabric.

[0039] The present invention also provides a flame-retardant silk fabric prepared by the preparation method as described above, which comprises a silk fabric and a coating on the surface of the silk fiber, wherein the coating is formed by the reaction of gallic acid, polyethyleneimine and a multivalent metal salt.

[0040] The principle of the present invention is: by combining gallic acid (GA), polyethyleneimine (PEI) and metal ions, a durable flame retardant for silk fabrics is obtained. PEI and GA form a self-crosslinking network through Schiff base reaction or Michael addition, and further complex with metal ions to construct a PEI-GA / Me flame retardant system, thereby giving silk fabrics durable flame retardant properties.

[0041] The specific flame retardant mechanism is as follows: GA and PEI first decompose to generate non-combustible gases (such as H2O, NH3 and CO2), which dilute the combustible gases and oxygen and take away the heat generated by combustion. In addition, the catechol groups in GA show strong scavenging ability for free radicals. During the combustion process, it can capture highly active free radicals (H· and OH·), interrupt the combustion reaction, and thus provide a gas phase flame retardant effect. At the same time, metal ions and catechol groups work synergistically in the condensed phase to accelerate the formation of a dense carbon layer. Metal ions combine with oxygen to form metal oxides, which are evenly distributed on the surface of the residual carbon, making the carbon layer more dense and stable. This carbon layer can prevent heat and oxygen from entering the silk matrix, increase the amount of residual carbon, and reduce further thermal degradation of the matrix. Therefore, the PEI-GA / Me system works synergistically in the gas phase and condensed phase, giving silk fabrics excellent flame retardant properties. Among them, GA has a strong chelating ability, acts with metal ions through coordination bonds, and forms a ternary complex with silk to improve the washability of the fabric. In addition, silk fabrics treated with GA and Fe3+ complex also have excellent antibacterial properties.

[0042] Due to the adoption of the above technical scheme, the present invention has the following advantages compared with the prior art: the preparation method of the flame-retardant silk fabric of the present invention, the obtained PEI-GA / Me flame-retardant system provides excellent and stable flame retardancy for the silk fabric, and overcomes the defect of poor flame retardancy durability of the fabric by natural molecular flame retardants; the raw materials used are green, environmentally friendly and pollution-free, and conform to the ecological concept of energy conservation and emission reduction; the preparation method has low processing temperature and simple operation, and mass production is achieved by the roller dyeing method. The fabric integrates flame retardancy and antibacterial properties, which can increase the added value of the product; the prepared flame-retardant silk fabric has a vertical burning damage length of less than 15 cm after 50 washings, and the LOI value is higher than 27%, which has good flame retardant stability; the antibacterial property against Staphylococcus aureus is 99.8%, and the feel of the fabric does not change. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0044] Figure 1 The vertical combustion test photos of the durable flame-retardant silk fabrics prepared in Examples 1-4 of the present invention and the original silk sample (untreated silk fabric) and the damaged char length and LOI value;

[0045] Figure 2The vertical combustion test photos, damaged char length and LOI value of the durable flame-retardant silk fabrics prepared in Examples 1-4 of the present invention after 20 washes;

[0046] Figure 3 The vertical combustion char length and LOI test results of the durable flame retardant silk fabric prepared in Example 2 of the present invention before and after washing;

[0047] Figure 4 These are photos showing the antibacterial properties of the durable flame-retardant silk fabric prepared in Example 2 of the present invention and the untreated silk fabric. DETAILED DESCRIPTION

[0048] In order to enable those skilled in the art to better understand the technical solution of the present invention, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0049] The durable flame-retardant silk fabric and preparation method thereof of the present invention prepare a PEI-GA / Me composite coated silk fabric by forming a self-crosslinking network of PEI and GA on the surface of the fabric and chelating with metal ions (Me), thereby solving the environmental protection problem of flame retardants and the durability problem of natural molecular flame retardants, and providing the fabric with antibacterial function while meeting the flame retardant performance.

[0050] The present invention successfully applies a flame-retardant and antibacterial coating that does not contain phosphorus and halogen to silk fabrics under mild conditions through a simple roller dyeing and drying process. The preparation process of the present invention is simple and can be mass-produced. The roller dyeing process used has a low bath ratio, which saves costs, and the silk fabric is not easy to wrinkle. It provides a new strategy for using renewable biomass resources to prepare durable and multifunctional flame-retardant silk. Specifically, the preparation method of the durable flame-retardant silk fabric of the present invention uses silk fabric as a substrate and comprises the following steps:

[0051] (1) Preparation of finishing liquid

[0052] Gallic acid is mixed with deionized water at 40-60° C. to completely dissolve the gallic acid in the deionized water, thereby obtaining a gallic acid aqueous solution with a concentration of 5 g / L-10 g / L.

[0053] The polyethyleneimine is mixed with deionized water at 30-50° C. to completely dissolve the polyethyleneimine in the deionized water to obtain a polyethyleneimine aqueous solution with a concentration of 5 g / L-50 g / L. The polyethyleneimine has a molecular weight of 500-5000.

[0054] The gallic acid aqueous solution and the polyethyleneimine aqueous solution are mixed uniformly in a volume ratio of 1:2 to 1:4, and an alkali solution is added to adjust the pH value to 8 to 10 to obtain a finishing solution. The alkali solution is a 5 g / L to 20 g / L sodium hydroxide solution.

[0055] (2) Fabric finishing

[0056] Add the finishing liquid into the dyeing tank of the jigger, raise the temperature to 35°C to 50°C, pass the degummed silk fabric through the dyeing tank at a bath ratio of 1:3 to 1:5 and wind it on the cloth winding roller, the jigger speed is 5 to 10 m / min, reciprocate 2 times, wash once, and exit the machine to obtain the silk fabric treated with the finishing liquid.

[0057] (3) Preparation of polyvalent metal salt solution

[0058] In another jigger, a polyvalent metal salt aqueous solution with a concentration of 5 g / L to 50 g / L is prepared and heated to 40° C. to 60° C. The polyvalent metal salt is one or more selected from ferrous sulfate, ferric sulfate, aluminum sulfate, and titanium sulfate.

[0059] (4) Treatment of metal salts

[0060] The silk fabric treated with the finishing liquid is moved to the jigger of the above-mentioned multivalent metal salt solution, the rotation speed of the jigger is 5-10 m / min, after 2 reciprocating passes, 3 water washing passes, and then the silk fabric with flame retardant finishing is obtained; the bath ratio during jigger dyeing is 1:3-1:5.

[0061] (5) Drying

[0062] The flame-retardant finished silk fabric is moved to a drying room and dried at 50-90°C for 20-40 minutes to obtain a durable flame-retardant silk fabric, which includes a silk fabric and a surface coating, wherein the coating is formed by the reaction of gallic acid with polyethyleneimine and a polyvalent metal salt, PEI and GA form a self-crosslinking network through Schiff base reaction or Michael addition, and further complexed with metal ions to construct a PEI-GA / Me flame-retardant system, thereby giving the silk fabric a durable flame-retardant property.

[0063] Example 1

[0064] Preparation method of durable flame retardant silk fabric in this embodiment (ferrous sulfate, Fe 2+ ), the specific steps are as follows:

[0065] (1) Preparation of finishing solution: 10 g / L gallic acid aqueous solution and 10 g / L polyethyleneimine (Mw molecular weight: 1000) aqueous solution were mixed in a volume ratio of 1:2, and 20 g / L sodium hydroxide solution was added to adjust the pH value to 9.5.

[0066] (2) Fabric finishing: Add the finishing liquid into the dyeing tank of the jigger, raise the temperature to 50°C, pass the degummed silk fabric through the dyeing tank at a bath ratio of 1:4 and wind it on the cloth winding roller. The jigger rotates at a speed of 10 m / min, performs 2 reciprocating passes, 1 water wash pass, and exits the machine to obtain the silk fabric treated with the finishing liquid.

[0067] (3) Preparation of polyvalent metal salt solution: In another jigger, prepare an aqueous solution of ferrous sulfate with a concentration of 20 g / L and heat it to 50°C.

[0068] (4) Treatment with metal salts: The silk fabric treated with the finishing liquid obtained in step (2) is transferred to the above-mentioned jigger with a bath ratio of 1:4 and a rotation speed of 10 m / min. After two reciprocating passes, the fabric is washed with water three times and then removed from the machine to obtain a flame-retardant finished silk fabric.

[0069] (5) Drying: The flame-retardant treated silk fabric is moved to a drying room and dried at 50°C for 30 minutes to obtain a durable flame-retardant silk fabric.

[0070] Example 2

[0071] Preparation method of durable flame retardant silk fabric in this embodiment (ferrous sulfate, Fe 3 +), the specific steps are as follows:

[0072] (1) Preparation of finishing solution: 5 g / L gallic acid aqueous solution and 5 g / L polyethyleneimine (Mw molecular weight 600) aqueous solution were mixed at a ratio of 1:4, and 5 g / L sodium hydroxide was added to adjust the pH value to 8.5.

[0073] (2) Fabric finishing: Add the finishing liquid into the dyeing tank of the jigger, raise the temperature to 40°C, immerse the degummed silk fabric in the finishing liquid at a bath ratio of 1:5, rotate the jigger at 5 m / min, do 2 reciprocating passes, 1 water wash, and exit the machine to obtain the silk fabric treated with the finishing liquid.

[0074] (3) Preparation of polyvalent metal salt solution: In another jigger, prepare an aqueous solution of ferric sulfate with a concentration of 10 g / L and heat it to 40°C.

[0075] (4) Treatment with metal salts: The silk fabric treated with the finishing liquid obtained in step (2) is transferred to the above-mentioned jigger with a bath ratio of 1:5 and a rotation speed of 5 m / min. After two reciprocating passes, the jigger is washed with water three times and then taken out of the machine to obtain a flame-retardant finished silk fabric.

[0076] (5) Drying: The flame-retardant treated silk fabric is moved to a drying room and dried at 40°C for 40 minutes to obtain a durable flame-retardant silk fabric.

[0077] Example 3

[0078] Preparation method of durable flame retardant silk fabric in this embodiment (aluminum sulfate, Al 3 +), the specific steps are as follows:

[0079] (1) Preparation of finishing solution: 5 g / L gallic acid aqueous solution and 15 g / L polyethyleneimine (Mw molecular weight: 2000) aqueous solution were mixed at a ratio of 1:4, and 5 g / L sodium hydroxide was added to adjust the pH value to 9.

[0080] (2) Fabric finishing: Add the finishing liquid into the dyeing tank of the jigger, raise the temperature to 60°C, immerse the degummed silk fabric in the finishing liquid at a bath ratio of 1:4, rotate the jigger at 5 m / min, do 2 reciprocating passes, 1 water wash, and exit the machine to obtain the silk fabric treated with the finishing liquid.

[0081] (3) Preparation of polyvalent metal salt solution: In another jigger, prepare an aqueous solution of aluminum sulfate with a concentration of 10 g / L and heat it to 60°C.

[0082] (4) Treatment with metal salts: The silk fabric treated with the finishing liquid obtained in step (2) is transferred to the above-mentioned jigger with a bath ratio of 1:4 and a rotation speed of 5 m / min. After two reciprocating passes, the jigger is washed with water three times and then taken out of the machine to obtain a flame-retardant finished silk fabric.

[0083] (5) Drying: The flame-retardant treated silk fabric is moved to a drying room and dried at 60°C for 20 minutes to obtain a durable flame-retardant silk fabric.

[0084] Example 4

[0085] The method for preparing the durable flame retardant silk fabric in this embodiment (titanium sulfate, Ti 4 +), the specific steps are as follows:

[0086] (1) Preparation of finishing solution: 10 g / L gallic acid aqueous solution and 20 g / L polyethyleneimine (Mw molecular weight: 2500) aqueous solution were mixed at a ratio of 1:3, and 10 g / L sodium hydroxide was added to adjust the pH value to 9.3.

[0087] (2) Fabric finishing: Add the finishing liquid into the dyeing tank of the jigger, raise the temperature to 50°C, immerse the degummed silk fabric in the finishing liquid at a bath ratio of 1:3, rotate the jigger at 10 m / min, do 2 reciprocating passes, 1 water wash, and exit the machine to obtain the silk fabric treated with the finishing liquid.

[0088] (3) Preparation of polyvalent metal salt solution: In another jigger, prepare a titanium sulfate aqueous solution with a concentration of 10 g / L and heat it to 50°C.

[0089] (4) Treatment with metal salts: The silk fabric treated with the finishing liquid obtained in step (2) is transferred to the above-mentioned jigger with a bath ratio of 1:3 and a rotation speed of 10 m / min. After two reciprocating passes, the jigger is washed with water three times and then taken out of the machine to obtain a flame-retardant finished silk fabric.

[0090] (5) Drying: The flame-retardant treated silk fabric is moved to a drying room and dried at 50°C for 30 minutes to obtain a durable flame-retardant silk fabric.

[0091] Tests and Results

[0092] The flame retardant properties of the silk fabric prepared in the embodiment of the present invention are measured according to GB / T 5454-1997 "Textile Combustion Performance Test Oxygen Index Method" and GB / T 5455-2014 "Textile Combustion Performance Vertical Direction Damage Length Smoldering and Afterflaming Time Determination". The washing method of the flame retardant silk fabric is carried out in accordance with the standard of GB / T 3921-2008 "Textile Color Fastness Test Color Fastness to Soaping", using 2g / L of a special detergent for silk and wool fabrics, a bath ratio of 1:50, and washing at 40°C for 30min. Repeat the washing for the required number of times.

[0093] (1) Flame retardant test

[0094] The vertical combustion test photos of the durable flame retardant silk fabrics prepared in Examples 1-4 and the original silk (untreated silk fabrics) and the results of the damaged char length and LOI value are shown in the figure below: Figure 1 shown.

[0095] Depend on Figure 1 It can be seen that the untreated silk fabric burned rapidly after contact with the flame and was completely incinerated within 12 seconds, with almost the entire sample (30 cm) being burned. In contrast, the treated fabric quickly extinguished itself after contact with the flame, the spread of the flame was completely suppressed, and the fabric was carbonized at high temperature. 2+ , Fe 3+ 、Al 3+ and Ti 4+ The damaged lengths of the treated fabrics were 9.2 cm, 8.3 cm, 9.3 cm and 8.2 cm respectively, which were significantly shorter than those of the untreated silk fabrics. This shows that the flame retardant properties of the treated silk fabrics have been significantly improved, reaching the B1 flame retardant standard. According to the Chinese standard GB / T17591, the B1 flame retardant requires a carbonization length of less than 15 cm.

[0096] Meanwhile, the LOI values ​​of the treated fabrics increased to 29.8%, 30.2%, 27.4% and 33.0%, respectively, compared to 25.0% for the untreated silk. The significant increase in LOI values ​​can be attributed to the formation of a char layer, which acts as an insulator, hindering the transfer of heat and combustible materials, thereby slowing down the combustion process.

[0097] (2) Durability test

[0098] The vertical burning test photos of the durable flame retardant silk fabrics prepared in Examples 1-4 after 20 washes and the results of the damaged char length and LOI value are shown in the figure below: Figure 2 shown.

[0099] Depend on Figure 2 It can be seen that after 20 washes, the damage length of the fabrics treated with the four metal salts after the vertical burning test was less than 15 cm. 3+ For the fabric treated with ions, there was no obvious flame spread and the damage length hardly changed, indicating that the fabric still had good flame retardant durability after washing.

[0100] Fe 3+ The ion-treated fabric (Example 2) was subjected to more washing tests, such as Figure 3 As shown in (Test results of vertical burning char length and LOI of durable flame retardant silk fabric prepared in Example 2 before and after washing), after 50 washes, the LOI value of the silk fabric still exceeded 27%, and the carbonization damage length was close to 15 cm, but the fabric still met the B1 flame retardant standard. These results show that the flame retardancy and washability of silk fabrics can be effectively improved by co-deposition modification of GA, PEI and metal ions.

[0101] (3) Antibacterial test

[0102] Figure 4 These are photos showing the antibacterial properties of the durable flame-retardant silk fabric prepared in Example 2 and the untreated silk fabric.

[0103] Depend on Figure 4 It can be seen that the antibacterial property of untreated silk fabric is poor because silk protein provides nutrition for bacteria. In contrast, by counting the number of colonies on the culture dish and calculating the antibacterial rate, it can be concluded that the antibacterial rate of the durable flame-retardant silk fabric of Example 2 against Escherichia coli is 78.6%, and the antibacterial rate against Staphylococcus aureus is 99.8%. This shows that the durable flame-retardant silk fabric has antibacterial properties in addition to excellent durable flame-retardant properties.

[0104] The invention discloses a durable flame-retardant silk fabric and a preparation method thereof, which belongs to the field of functional finishing of textiles. The preparation steps are as follows: gallic acid (GA), polyethyleneimine (PEI) and metal ions are combined to prepare the flame-retardant silk fabric by a simple roller dyeing-drying method. After different metal ions (Fe 2+ , Fe 3+ 、Al 3+ and Ti 4+ ) modified silk fabrics all showed self-extinguishing properties in the vertical burning test, with damaged char lengths of 9.2, 8.3, 9.3 and 8.2 cm, and limiting oxygen index (LOI) values ​​of 29.8%, 30.2%, 27.4% and 33.0%, respectively. After 50 washing cycles, Fe 3+ The length of damaged char on treated silk remained below 15 cm. 3+ The treated silk also exhibits excellent antibacterial properties. The simple and environmentally friendly method for preparing functionalized silk fabrics in this application provides a new approach for developing advanced and sustainable silk textiles.

[0105] The above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with this technology to understand the contents of the present invention and implement them accordingly. They cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

[0106] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

Claims

1. A method for preparing a flame retardant silk fabric, characterized in that: The steps include: The gallic acid aqueous solution and the polyethyleneimine aqueous solution are mixed uniformly, and an alkali solution is added to adjust the pH value to alkaline to obtain a finishing solution; The degummed silk fabric is treated for the first time with the finishing liquid to obtain the silk fabric treated with the finishing liquid; Preparing a multivalent metal salt solution, and using the multivalent metal salt solution to perform a second treatment on the silk fabric treated with the finishing liquid to obtain a flame-retardant finished silk fabric; The flame-retardant finished silk fabric is dried to obtain the flame-retardant silk fabric.

2. The preparation method according to claim 1, characterized in that: The gallic acid aqueous solution is prepared by the following method: gallic acid is mixed with deionized water at 40-60° C., and the gallic acid is completely dissolved in the deionized water to obtain a gallic acid aqueous solution with a concentration of 5 g / L-10 g / L.

3. The preparation method according to claim 1, characterized in that: The polyethyleneimine aqueous solution is prepared by the following method: polyethyleneimine is mixed with deionized water at 30-50° C. to completely dissolve the polyethyleneimine in the deionized water to obtain a polyethyleneimine aqueous solution with a concentration of 5 g / L-50 g / L; the weight average molecular weight of the polyethyleneimine is 500-5000.

4. The preparation method according to claim 1, characterized in that: The volume ratio between the gallic acid aqueous solution and the polyethyleneimine aqueous solution is 1:2 to 1:

4.

5. The preparation method according to claim 1, characterized in that: The alkali solution is a sodium hydroxide solution with a concentration of 5g / L to 20g / L, and the pH of the finishing solution is 8 to 10.

6. The preparation method according to claim 1, characterized in that: The multivalent metal salt is one or more selected from ferrous sulfate, ferric sulfate, aluminum sulfate, and titanium sulfate; the concentration of the multivalent metal salt solution is 5 g / L to 50 g / L.

7. The preparation method according to claim 1, characterized in that: The first treatment is: adding the finishing liquid into the dyeing tank of the jigger, heating it to 35°C to 50°C, winding the degummed silk fabric on the cloth winding roller through the dyeing tank, and obtaining the silk fabric treated with the finishing liquid after jigger dyeing.

8. The preparation method according to claim 1, characterized in that: The second treatment is as follows: adding the metal salt aqueous solution into the dyeing tank of the jigger, heating it to 40°C to 60°C, moving the silk fabric treated with the finishing liquid into the jigger, and obtaining the flame-retardant finished silk fabric after jigger dyeing.

9. The preparation method according to claim 1, characterized in that: The drying temperature is 50-90° C. and the drying time is 20-40 minutes.

10. A flame retardant silk fabric prepared by the preparation method according to any one of claims 1 to 9.

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