Flame-retardant silk fabric with PEI-GA / Me composite coating

Abstract

The invention discloses a flame-retardant silk fabric with a PEI-GA / Me composite coating, the flame-retardant silk fabric comprises a silk fabric and a coating on the surface of the silk fabric, and the coating is formed after gallic acid reacts with polyethyleneimine and polyvalent metal salt; the multivalent metal salt is selected from one or more of ferrous sulfate, ferric sulfate, aluminum sulfate and titanium sulfate. According to the flame-retardant silk fabric with the PEI-GA / Me composite coating, a self-crosslinking network of PEI and GA is formed on the surface of the fabric and is chelated with metal ions (Me), so that the environmental protection problem of a flame retardant and the durability problem of a natural molecular flame retardant are solved, and an antibacterial function is provided for the fabric while the flame-retardant property is met.

Description

[0001] This application is a divisional application of the invention patent application filed on December 16, 2024, with application number 2024118504590 and invention title "A flame-retardant silk fabric and its preparation method". Technical Field

[0002] This invention belongs to the field of flame retardant and functional finishing technology of textiles, specifically relating to a method for preparing a durable flame-retardant silk fabric with a PEI-GA / Me composite coating and the flame-retardant silk fabric prepared by the method. Background Technology

[0003] Silk, with its excellent breathability, skin-friendliness, moisture absorption, smoothness, and softness, is widely used in high-end clothing and home textiles. However, ordinary silk is flammable and burns rapidly, threatening user safety. The inherent flammability of silk limits its application potential and safety. Flame-retardant silk fabrics can enhance fire safety while maintaining their aesthetic appeal, making them an ideal choice for luxury home textiles and high-end fashion. Furthermore, because the protein structure of silk provides a favorable environment for bacterial growth, its antibacterial properties are poor, further highlighting the need for multifunctional silk fabrics that integrate flame retardancy with other functions.

[0004] Halogenated compounds were once widely used due to their excellent flame-retardant properties, but were eventually restricted or banned due to their toxicity, bioaccumulation, and environmental pollution problems. Commonly used phosphorus-based flame retardants may release formaldehyde during use. Furthermore, the accumulation of phosphorus in the natural environment can lead to eutrophication of lakes and other water bodies, not only damaging aquatic ecosystems but also posing a long-term threat to the entire environment. Due to these serious problems, the textile flame retardant industry is actively exploring new alternatives, with phosphorus- and halogen-free compounds becoming the mainstream trend for future development. This shift aims to balance the flame-retardant properties of textiles with the needs of environmental protection and human health, driving the textile industry towards a greener and safer direction.

[0005] In recent years, natural compounds and their derivatives have become an important research hotspot as environmentally friendly flame retardants for textiles. 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 advantages such as low cost, non-toxicity, safety, and renewability. For example, by adsorbing bio-based flavonoids and then mordant-treating them with metal salts, the resulting complex 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 do not perform well in terms of wash resistance.

[0006] Gallic acid (GA) is a widely distributed natural polyphenol with a phenolic hydroxyl structure, endowing it with multiple functions such as antibacterial, antioxidant, antiviral and anti-inflammatory properties. 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 crosslinking properties. For example, two modified gallic acids (GAP and GAN) have been prepared as reactive flame retardants and crosslinkers 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 flameretardants and cross-linkers for the fabrication of flame-retardant polyurethane elastomers, Chemistry Select 8(39) (2023) e202302496].

[0007] Amino-quinone network (AQN) coating is a recent advancement in mussel-inspired chemistry. This method involves a Michael addition / Schiff base reaction between polyamine compounds and quinone compounds derived from the oxidation of polyphenolic compounds to form a self-crosslinking coating. Advantages of the AQN coating method include a one-step reaction process, mild conditions, and the durability of the resulting coating. Polyethyleneimine (PEI), rich in reactive primary amino groups, can react with GA to form a self-crosslinking network. The AQN system can remove the hydration layer from the material surface, resulting in strong adhesion. Furthermore, studies have shown that nitrogen-modified polyphenols are effective in reducing the peak heat release rate of cellulose fibers. This supports the application of AQN in flame retardant textiles.

[0008] For example, patent CN201910565152.9 describes a method for preparing formaldehyde-free, washable, flame-retardant fabric. This method involves immersing a fabric fixed with natural polyphenolic compounds in a metal salt solution to obtain the formaldehyde-free, washable, flame-retardant fabric. However, the preparation process requires immersing the fabric with deposited natural polyphenolic compounds in a fixative solution, which is at least one of tartaric acid solution, chitosan solution, color-fixing agent Y solution, or water-soluble polyurethane color-fixing agent solution. Color-fixing agent Y has a high free formaldehyde content; the other three color-fixing agents improve the flame-retardant durability of the fabric by forming a film on the fabric surface, which affects the fabric's hand feel.

[0009] For example, patent CN201811270759.6 describes a flame-retardant silk fabric and its preparation method and application. The method involves immersing silk in a solution of tannic acid and metal salts to prepare flame-retardant silk fabric. However, the limiting oxygen index of the unwashed silk fabric is only 27.5%, indicating that the effect needs improvement. Furthermore, the method requires a relatively high processing temperature, preventing mass production.

[0010] The above background information is provided only to assist in understanding the inventive concept and technical solution of this invention. It does not necessarily belong to the prior art of this patent application. In the absence of clear evidence that the above information was disclosed before the filing date of this patent application, the above background information should not be used to evaluate the novelty and inventiveness of this application. Summary of the Invention

[0011] In view of this, in order to overcome the shortcomings of the prior art, the purpose of this invention is to provide an improved flame-retardant silk fabric with better flame-retardant durability.

[0012] To achieve the above objectives, the present invention adopts the following technical solution: A method for preparing flame-retardant silk fabric includes the following steps: Gallic acid aqueous solution and polyethyleneimine aqueous solution are mixed evenly, and alkali solution is added to adjust the pH value to alkaline to obtain the finishing solution; The finishing solution was used to perform a first treatment on the degummed silk fabric to obtain the finishing solution-treated silk fabric. A multivalent metal salt solution is prepared, and the silk fabric treated with the finishing solution is subjected to a second treatment using the multivalent metal salt solution to obtain a flame-retardant finished silk fabric. The flame-retardant treated silk fabric is dried to obtain the flame-retardant silk fabric.

[0013] According to some preferred embodiments of the present invention, the gallic acid aqueous solution is prepared by mixing gallic acid with deionized water at 40-60 °C to completely dissolve the gallic acid in the deionized water, thereby obtaining an aqueous solution of gallic acid with a concentration of 5 g / L to 10 g / L.

[0014] According to some preferred embodiments of the present invention, the polyethyleneimine aqueous solution is prepared by mixing polyethyleneimine 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 to 50 g / L.

[0015] According to some preferred embodiments of the invention, the weight-average molecular weight of the polyethyleneimine is 500 to 5000.

[0016] 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.

[0017] According to some preferred embodiments of the present invention, the alkaline 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.

[0018] According to some preferred embodiments of the present invention, the polyvalent metal salt is one or more selected from ferrous sulfate, ferric sulfate, aluminum sulfate, and titanium sulfate; the concentration of the polyvalent metal salt solution is 5 g / L to 50 g / L.

[0019] According to some preferred embodiments of the present invention, the first treatment is as follows: adding finishing liquid into the dyeing tank of a roll dyeing machine, heating to 35 ℃~50 ℃, and winding the degummed silk fabric through the dyeing tank onto the roll roller, obtaining the finishing liquid-treated silk fabric after roll dyeing; the bath ratio during roll dyeing is 1:3~1:5.

[0020] According to some preferred embodiments of the present invention, the second treatment is as follows: adding a polyvalent metal salt aqueous solution to the dyeing tank of the dyeing machine, heating to 40 ℃~60 ℃, transferring the finished silk fabric to the dyeing machine, and obtaining a flame-retardant finished silk fabric after dyeing; the bath ratio during dyeing is 1:3~1:5.

[0021] According to some preferred embodiments of the invention, the drying temperature is 50–90°C and the time is 20–40 minutes.

[0022] In some embodiments of the present invention, the method for preparing durable flame-retardant silk fabric, using silk fabric as the base material, includes the following steps: (1) Preparation of finishing solution Gallic acid is mixed with deionized water at 40–60 °C to completely dissolve the gallic acid in the deionized water, resulting in an aqueous solution of gallic acid with a concentration of 5 g / L to 10 g / L.

[0023] Polyethyleneimine was mixed with deionized water at 30–50 °C to completely dissolve the polyethyleneimine in the deionized water, resulting in an aqueous solution of polyethyleneimine with a concentration of 5 g / L to 50 g / L.

[0024] Gallic acid aqueous solution and polyethyleneimine aqueous solution are mixed evenly at a volume ratio of 1:2 to 1:4, and alkali solution is added to adjust the pH value to 8 to 10 to obtain the finishing solution.

[0025] (2) Finishing of fabrics Add the finishing solution to the dyeing tank of the dyeing machine, heat it to 35 ℃~50 ℃, and wind the degummed silk fabric through the dyeing tank onto the roll roller at a bath ratio of 1:3~1:5. The speed of the dyeing machine is 5~10 meters / minute, repeating 2 times, followed by 1 water wash, and then exiting the machine to obtain the silk fabric treated with the finishing solution.

[0026] (3) Preparation of polyvalent metal salt solutions In another dyeing machine, a polyvalent metal salt aqueous solution with a concentration of 5 g / L to 50 g / L is prepared and heated to 40℃ to 60℃. The polyvalent metal salt is one or more selected from ferrous sulfate, ferric sulfate, aluminum sulfate, and titanium sulfate.

[0027] (4) Treatment of metal salts The silk fabric treated with the finishing solution is transferred to a dyeing machine containing the above-mentioned polyvalent metal salt solution. The dyeing machine rotates at a speed of 5 to 10 meters per minute, and the liquor ratio during dyeing is 1:3 to 1:5. After two reciprocating passes, the fabric is washed three times with water and then exits the machine to obtain a flame-retardant finished silk fabric.

[0028] (5) Drying The flame-retardant treated silk fabric is transferred to a drying room and dried at 50-90℃ for 20-40 minutes to obtain a durable flame-retardant silk fabric.

[0029] The present invention also provides a flame-retardant silk fabric prepared by the preparation method described above, comprising a silk fabric and a coating on the surface of the silk fibers, wherein the coating is formed by reacting gallic acid with polyethyleneimine and a polyvalent metal salt.

[0030] The principle of this invention is as follows: a durable flame retardant for silk fabrics is obtained by combining gallic acid (GA), polyethyleneimine (PEI), and metal ions. PEI and GA form a self-crosslinking network through Schiff base reaction or Michael addition, and further complex with metal ions to construct the PEI-GA / Me flame retardant system, thereby endowing silk fabrics with durable flame retardant properties.

[0031] The specific flame-retardant mechanism is as follows: GA and PEI first decompose to generate non-flammable gases (such as H2O, NH3, and CO2). These gases dilute the flammable gases and oxygen, while carrying away the heat generated by combustion. Furthermore, the catechol groups in GA exhibit a strong ability to scavenge free radicals. During combustion, it can capture highly reactive free radicals (H• and OH•), interrupting the combustion reaction and thus providing a gas-phase flame-retardant effect. Simultaneously, 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 uniformly distributed on the surface of the char residue, making the carbon layer more dense and stable. This carbon layer can prevent heat and oxygen from entering the silk matrix, increasing the char residue and reducing further thermal degradation of the matrix. Therefore, the PEI-GA / Me system works synergistically in both the gas and condensed phases, giving silk fabrics excellent flame-retardant properties. GA has a strong chelating ability, interacting with metal ions through coordination bonds and forming a ternary complex with silk, thereby improving the fabric's washability. In addition, GA and Fe... 3+ The composite-treated silk fabrics also have excellent antibacterial properties.

[0032] Due to the adoption of the above technical solutions, the present invention has the following advantages compared with the prior art: The preparation method of flame-retardant silk fabric of the present invention provides the PEI-GA / Me flame-retardant system with excellent and stable flame retardancy for silk fabric, overcoming the defect of poor flame retardant durability of natural molecular flame retardants; the raw materials used are green, environmentally friendly and pollution-free, in line with the ecological concept of energy conservation and emission reduction; the preparation method has a low processing temperature and simple operation, and mass production is achieved by using a roll dyeing method. The fabric integrates flame retardant 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 15cm after 50 washes, an LOI value of more than 27%, and good flame retardant stability; the antibacterial performance against Staphylococcus aureus is 99.8%, and the hand feel of the fabric remains unchanged. Attached Figure Description

[0033] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0034] Figure 1 The images show vertical burning test photos of the durable flame-retardant silk fabrics prepared in Examples 1-4 of this invention and the original silk fabric (untreated silk fabric), as well as the damaged char length and LOI value. Figure 2The images show the vertical burning test photos, char length, and LOI value of the durable flame-retardant silk fabrics prepared in Examples 1-4 of this invention after 20 washes. Figure 3 The results of vertical burning char length and LOI tests on the durable flame-retardant silk fabric prepared in Example 2 of this invention before and after washing; Figure 4 The images show the antibacterial properties of the durable flame-retardant silk fabric prepared in Example 2 of this invention and the untreated silk fabric. Detailed Implementation

[0035] To enable those skilled in the art to better understand the technical solutions of the present invention, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. 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 skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0036] The present invention relates to a durable flame-retardant silk fabric and its preparation method. By forming a self-crosslinking network of PEI and GA on the fabric surface and chelating it with metal ions (Me), a PEI-GA / Me composite coated silk fabric is prepared. This solves the environmental protection problem of flame retardants and the durability problem of natural molecular flame retardants, and provides antibacterial function to the fabric while meeting the flame retardant performance requirements.

[0037] This invention successfully applies a phosphorus- and halogen-free flame-retardant and antibacterial coating to silk fabrics under mild conditions through a simple dyeing and drying process. The preparation process is simple, allows for mass production, and the dyeing process uses a low liquor ratio, saving costs and reducing wrinkling of the silk fabric. This provides a new strategy for preparing durable, multifunctional flame-retardant silk using renewable biomass resources. Specifically, the method for preparing durable flame-retardant silk fabrics of this invention, using silk fabric as the base material, includes the following steps: (1) Preparation of finishing solution Gallic acid is mixed with deionized water at 40–60 °C to completely dissolve the gallic acid in the deionized water, resulting in an aqueous solution of gallic acid with a concentration of 5 g / L to 10 g / L.

[0038] Polyethyleneimine was mixed with deionized water at 30–50 °C until it was completely dissolved, yielding an aqueous solution of polyethyleneimine with a concentration of 5 g / L to 50 g / L. The molecular weight (Mw) of polyethyleneimine was 500–5000.

[0039] Gallic acid aqueous solution and polyethyleneimine aqueous solution are mixed evenly at a volume ratio of 1:2 to 1:4. The pH is then adjusted to 8–10 with the addition of an alkaline solution to obtain the finishing solution. The alkaline solution is a sodium hydroxide solution with a concentration of 5 g / L to 20 g / L.

[0040] (2) Finishing of fabrics Add the finishing solution to the dyeing tank of the dyeing machine, heat it to 35 ℃~50 ℃, and wind the degummed silk fabric through the dyeing tank onto the roll roller at a bath ratio of 1:3~1:5. The speed of the dyeing machine is 5~10 meters / minute, repeating 2 times, followed by 1 water wash, and then exiting the machine to obtain the silk fabric treated with the finishing solution.

[0041] (3) Preparation of polyvalent metal salt solutions In another dyeing machine, a polyvalent metal salt aqueous solution with a concentration of 5 g / L to 50 g / L is prepared and heated to 40℃ to 60℃. The polyvalent metal salt is one or more selected from ferrous sulfate, ferric sulfate, aluminum sulfate, and titanium sulfate.

[0042] (4) Treatment of metal salts The silk fabric treated with the finishing solution is transferred to a dyeing machine containing the above-mentioned polyvalent metal salt solution. The dyeing machine rotates at a speed of 5 to 10 meters per minute, repeats twice, and then is washed three times with water before exiting the machine to obtain a flame-retardant finished silk fabric. The liquor ratio during dyeing is 1:3 to 1:5.

[0043] (5) Drying The flame-retardant treated silk fabric is transferred to a drying room and dried at 50-90°C for 20-40 minutes to obtain a durable flame-retardant silk fabric, which includes the silk fabric and a surface coating. The coating is formed by the reaction of gallic acid with polyethyleneimine and polyvalent metal salts. 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 endowing the silk fabric with durable flame-retardant properties.

[0044] Example 1 The method for preparing durable flame-retardant silk fabric in this embodiment (ferrous sulfate, Fe) 2+ The specific steps are as follows: (1) Preparation of finishing solution: Mix 10 g / L gallic acid aqueous solution and 10 g / L polyethyleneimine (Mw molecular weight is 1000) aqueous solution at a volume ratio of 1:2, and add 20 g / L sodium hydroxide solution to adjust the pH value to 9.5.

[0045] (2) Finishing the fabric: Add the finishing solution to the dyeing tank of the dyeing machine, heat it to 50 ℃, and roll the degummed silk fabric through the dyeing tank at a bath ratio of 1:4 onto the roll roller. The speed of the dyeing machine is 10 meters / minute, repeat 2 times, wash 1 time, and exit the machine to obtain the silk fabric treated with the finishing solution.

[0046] (3) Prepare a polyvalent metal salt solution: In another dyeing machine, prepare a ferrous sulfate aqueous solution with a concentration of 20 g / L and heat it to 50 ℃.

[0047] (4) Treatment with metal salts: The silk fabric treated with the finishing solution obtained in step (2) above is transferred to the above-mentioned dyeing machine with a liquor ratio of 1:4 and a dyeing machine speed of 10 m / min. After two reciprocating passes, it is washed with water three times and then removed from the machine to obtain a flame-retardant finished silk fabric.

[0048] (5) Drying: The flame-retardant silk fabric is placed in a drying room and dried at 50°C for 30 minutes to obtain a durable flame-retardant silk fabric.

[0049] Example 2 The method for preparing durable flame-retardant silk fabric in this embodiment (ferric sulfate, Fe) 3+ The specific steps are as follows: (1) Preparation of finishing solution: Mix 5 g / L gallic acid aqueous solution and 5 g / L polyethyleneimine (Mw molecular weight is 600) aqueous solution at a ratio of 1:4, and add 5 g / L sodium hydroxide to adjust the pH value to 8.5.

[0050] (2) Finishing of fabric: Add finishing solution to the dyeing tank of the dyeing machine, heat to 40 ℃, immerse the degummed silk fabric in the finishing solution at a bath ratio of 1:5, the speed of the dyeing machine is 5 meters / minute, repeat 2 times, wash once with water, and get out of the machine to obtain the silk fabric treated with finishing solution.

[0051] (3) Prepare a polyvalent metal salt solution: In another dyeing machine, prepare an aqueous solution of ferric sulfate with a concentration of 10 g / L and heat it to 40 ℃.

[0052] (4) Treatment with metal salts: The silk fabric treated with the finishing solution obtained in step (2) above is transferred to the above-mentioned dyeing machine with a liquor ratio of 1:5 and a dyeing machine speed of 5 meters / minute. After two reciprocating passes, it is washed with water three times and then removed from the machine to obtain a flame-retardant finished silk fabric.

[0053] (5) Drying: The flame-retardant silk fabric is placed in a drying room and dried at 40°C for 40 minutes to obtain a durable flame-retardant silk fabric.

[0054] Example 3 The method for preparing durable flame-retardant silk fabric in this embodiment (aluminum sulfate, Al) 3+The specific steps are as follows: (1) Preparation of finishing solution: Mix 5 g / L gallic acid aqueous solution and 15 g / L polyethyleneimine (Mw molecular weight is 2000) aqueous solution at a ratio of 1:4, and add 5 g / L sodium hydroxide to adjust the pH value to 9.

[0055] (2) Finishing of fabric: Add finishing solution to the dyeing tank of the dyeing machine, heat to 60 ℃, immerse the degummed silk fabric in the finishing solution at a bath ratio of 1:4, the speed of the dyeing machine is 5 meters / minute, repeat 2 times, wash once with water, and get out of the machine to obtain the silk fabric treated with finishing solution.

[0056] (3) Prepare a polyvalent metal salt solution: In another dyeing machine, prepare an aqueous solution of aluminum sulfate with a concentration of 10 g / L and heat it to 60 ℃.

[0057] (4) Treatment with metal salts: The silk fabric treated with the finishing solution obtained in step (2) above is transferred to the above-mentioned dyeing machine with a liquor ratio of 1:4 and a dyeing machine speed of 5 meters / minute. After two reciprocating passes, it is washed with water three times and then removed from the machine to obtain a flame-retardant finished silk fabric.

[0058] (5) Drying: The flame-retardant silk fabric is placed in a drying room and dried at 60°C for 20 minutes to obtain a durable flame-retardant silk fabric.

[0059] Example 4 The method for preparing durable flame-retardant silk fabric in this embodiment (titanium sulfate, Ti) 4+ The specific steps are as follows: (1) Preparation of finishing solution: Mix 10 g / L gallic acid aqueous solution and 20 g / L polyethyleneimine (Mw molecular weight is 2500) aqueous solution at a ratio of 1:3, and add 10 g / L sodium hydroxide to adjust the pH value to 9.3.

[0060] (2) Finishing of fabric: Add finishing solution to the dyeing tank of the dyeing machine, heat to 50 ℃, immerse the degummed silk fabric in the finishing solution at a bath ratio of 1:3, the speed of the dyeing machine is 10 m / min, repeat 2 times, wash once with water, and get out of the machine to obtain the silk fabric treated with finishing solution.

[0061] (3) Prepare a polyvalent metal salt solution: In another dyeing machine, prepare a titanium sulfate aqueous solution with a concentration of 10 g / L and heat it to 50 ℃.

[0062] (4) Treatment with metal salts: The silk fabric treated with the finishing solution obtained in step (2) above is transferred to the above-mentioned dyeing machine with a liquor ratio of 1:3 and a dyeing machine speed of 10 meters / minute. After two reciprocating passes, it is washed with water three times and then removed from the machine to obtain a flame-retardant finished silk fabric.

[0063] (5) Drying: The flame-retardant silk fabric is placed in a drying room and dried at 50°C for 30 minutes to obtain a durable flame-retardant silk fabric.

[0064] Tests and Results The flame-retardant properties of the silk fabrics prepared in this embodiment of the invention were determined according to GB / T 5454-1997 "Test for Burning Performance of Textiles - Oxygen Index Method" and GB / T 5455-2014 "Determination of Vertical Destruction Length and Afterflame Time of Burning Performance of Textiles". The washing method for the flame-retardant silk fabrics was carried out according to GB / T 3921-2008 "Test for Color Fastness of Textiles - Color Fastness to Soap Washing", using 2 g / L of a special detergent for silk and wool fabrics, a liquor ratio of 1:50, and washing at 40°C for 30 minutes as one wash. The washing was repeated until the required number of washes was reached.

[0065] (1) Flame retardant test The vertical burning test photographs and the results of the damaged char length and LOI value of the durable flame-retardant silk fabrics prepared in Examples 1-4 and the original silk sample (untreated silk fabric) are shown below. Figure 1 As shown.

[0066] Depend on Figure 1 It can be seen that the untreated silk fabric burned rapidly upon 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 self-extinguished rapidly upon contact with the flame, the spread of the flame was completely suppressed, and the fabric carbonized at high temperature. After being treated with Fe... 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, significantly shorter than those of the untreated silk fabrics. This indicates that the flame retardant properties of the treated silk fabrics were significantly improved, reaching the B1 flame retardant standard. According to the Chinese standard GB / T17591, the B1 flame retardant standard requires a char length of less than 15 cm.

[0067] 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 untreated silk. The significant increase in LOI value can be attributed to the formation of a carbonized layer, which acts as an insulator, hindering the transfer of heat and combustible materials, thereby slowing down the combustion process.

[0068] (2) Durability test The durable flame-retardant silk fabrics prepared in Examples 1-4 were subjected to vertical burning tests after 20 washes, and the results of the damaged char length and LOI value are shown below. Figure 2 As shown.

[0069] Depend on Figure 2 It can be seen that after 20 washes, the fabrics treated with the four metal salts all suffered damage lengths of less than 15 cm in the vertical burning test. Especially Fe... 3+ The ion-treated fabric showed no significant flame spread and almost no change in the damaged length, indicating that the fabric still has good flame-retardant durability after washing.

[0070] For Fe 3+ The ion-treated fabric (Example 2) underwent more washing tests, such as... Figure 3 (The results of vertical burning char length and LOI tests of the durable flame-retardant silk fabric prepared in Example 2 before and after washing) show that after 50 washes, the LOI value of the silk fabric still exceeded 27%, and the char damage length was close to 15 cm, but the fabric still met the B1 flame retardant standard. These results indicate that modifying silk fabrics by co-deposition of GA, PEI, and metal ions can effectively improve their flame retardancy and washability.

[0071] (3) Antibacterial test Figure 4 Photographs showing the antibacterial properties of the durable flame-retardant silk fabric prepared in Example 2 and the untreated silk fabric.

[0072] Depend on Figure 4 It is evident that untreated silk fabrics have poor antibacterial properties because silk protein provides nutrients for bacteria. In contrast, by counting the number of colonies on petri dishes and calculating the inhibition rate, it can be concluded that the durable flame-retardant silk fabric of Example 2 has an inhibition rate of 78.6% against Escherichia coli and 99.8% against Staphylococcus aureus. This indicates that the durable flame-retardant silk fabric, in addition to having excellent durable flame-retardant properties, also possesses antibacterial properties.

[0073] This invention relates to a durable flame-retardant silk fabric and its preparation method, belonging to the field of functional finishing of textiles. The preparation steps are as follows: A flame-retardant silk fabric is prepared by combining gallic acid (GA), polyethyleneimine (PEI), and metal ions through a simple dyeing-drying method. After processing with different metal ions (Fe... 2+ Fe 3+ Al 3+ and Ti 4+ The modified silk fabrics all exhibited self-extinguishing characteristics in vertical burning tests, 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 the damaged coke in the treated silk remained below 15 cm. (Fe) 3+The treated silk also exhibits excellent antibacterial properties. The simple and environmentally friendly method for preparing functionalized silk fabrics presented in this application provides a new approach for developing advanced and sustainable silk textiles.

[0074] The above embodiments are only for illustrating the technical concept and features of the present invention. Their purpose is to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be used to limit the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

[0075] The endpoints and any values ​​of the ranges disclosed herein 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 the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

Claims

1. A flame retardant silk fabric having a PEI-GA / Me composite coating, characterized in that, The application relates to a silk fabric and a coating on the surface of the silk fabric, wherein the coating is formed by reacting gallic acid with polyethylene imine and a multivalent metal salt; the multivalent metal salt is one or more selected from ferrous sulfate, ferric sulfate, aluminum sulfate and titanium sulfate.

2. The flame resistant silk fabric of claim 1, wherein, The vertical burning damage length of the flame-retardant silk fabric is less than 15 cm after 50 times of washing, and the LOI value is higher than 27%.

3. The flame resistant silk fabric of claim 1, wherein, The flame-retardant silk fabric is prepared by using a silk fabric as a base material through the following steps: (1) preparation of a finishing liquid: respectively prepare a gallic acid aqueous solution and a polyethylene imine aqueous solution; mix the gallic acid aqueous solution and the polyethylene imine aqueous solution, add an alkali solution to adjust the pH value to be alkaline, and obtain the finishing liquid; (2) finishing of the fabric: the finishing liquid is used to perform first treatment on degummed silk fabric, and a silk fabric treated by the finishing liquid is obtained; (3) preparation of a multivalent metal salt solution a multivalent metal salt solution with a concentration of 5 g / L to 50 g / L is prepared; (4) metal salt treatment: the silk fabric treated by the finishing liquid is treated by the multivalent metal salt solution for the second time, and a flame-retardant finished silk fabric is obtained; (5) drying: the flame-retardant finished silk fabric is dried, and the flame-retardant silk fabric is obtained.

4. The flame resistant silk fabric of claim 3, wherein, The gallic acid aqueous solution is prepared by the following method: gallic acid is mixed with deionized water at 40-60 DEG C, so that the gallic acid is completely dissolved in the deionized water, and a gallic acid aqueous solution with a concentration of 5 g / L to 10 g / L is obtained.

5. The flame resistant silk fabric of claim 3, wherein, The polyethylene imine aqueous solution is prepared by the following method: polyethylene imine is mixed with deionized water at 30-50 DEG C, so that the polyethylene imine is completely dissolved in the deionized water, and a polyethylene imine aqueous solution with a concentration of 5 g / L to 50 g / L is obtained; the weight average molecular weight of the polyethylene imine is 500-5000.

6. The flame resistant silk fabric of claim 3, wherein, The volume ratio between the gallic acid aqueous solution and the polyethylene imine aqueous solution is 1:2 to 1:

4.

7. The flame resistant silk fabric of claim 3, wherein, The alkali solution is a sodium hydroxide solution with a concentration of 5 g / L to 20 g / L, and the pH value of the finishing liquid is 8 to 10.

8. The flame retardant silk fabric as claimed in claim 3, wherein, The first treatment is as follows: the finishing liquid is added to a dyeing tank of a jigger, the temperature is raised to 35 DEG C to 50 DEG C, the degummed silk fabric is wound on a cloth roller through the dyeing tank, and the silk fabric treated by the finishing liquid is obtained after jigger dyeing; The second treatment is as follows: the metal salt aqueous solution is added to a dyeing tank of a jigger, the temperature is raised to 40 DEG C to 60 DEG C, the silk fabric treated by the finishing liquid is moved to the jigger, and the flame-retardant finished silk fabric is obtained after jigger dyeing.

9. The flame resistant silk fabric of claim 8, wherein, In the first treatment and / or the second treatment, the rotating speed of the jigger is 5-10 m / min, and the bath ratio during jigger dyeing is 1:3 to 1:

5.

10. The flame resistant silk fabric of claim 3, wherein, The drying temperature is 50-90 DEG C, and the drying time is 20-40 min.

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