Flame-retardant silk fabric and method for manufacturing the same

Abstract

The application discloses a preparation method of flame-retardant silk fabric, which comprises the following steps: uniformly mixing a gallic acid aqueous solution and a polyethylene imine aqueous solution, adding lye to adjust the pH value to alkaline, and obtaining a finishing liquid; performing first treatment on degummed silk fabric by using the finishing liquid to obtain silk fabric treated by the finishing liquid; configuring a polyvalent metal salt solution, and performing second treatment on the silk fabric treated by the finishing liquid by using the polyvalent metal salt solution to obtain flame-retardant finished silk fabric; and drying the flame-retardant finished silk fabric to obtain the flame-retardant silk fabric. According to the preparation method, a PEI-GA / Me composite coating silk fabric is prepared by forming a self-crosslinking network of PEI and GA on the surface of the fabric and chelating with metal ions (Me), the environmental protection problem of the flame retardant and the durability problem of the natural molecular flame retardant are solved, the flame-retardant performance is met, and the fabric is provided with antibacterial function.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of flame-retardant and textile functional finishing, and particularly relates to a preparation method of durable flame-retardant silk fabric and a flame-retardant silk fabric prepared by using the preparation method. BACKGROUND

[0002] Silk is widely used in high-end clothing and home textiles due to its excellent air permeability, skin-friendliness, and moisture absorption, as well as its smooth and soft properties. However, ordinary silk is flammable and burns rapidly, posing a threat to the safety of users. The flammability of silk itself limits its application potential and safety. Flame-retardant silk fabric can enhance fire safety while maintaining its aesthetic appeal, making it an ideal choice for luxury home textiles and high-end fashion. In addition, due to the protein structure of silk, which provides a favorable environment for bacterial growth, its antibacterial performance is poor, which further highlights the need for multifunctional silk fabric that integrates flame retardancy and other functions.

[0003] Halogen-containing compounds were 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 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, not only damaging aquatic ecosystems, but also posing 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 unrelated to phosphorus and halogen have become 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, and to promote the textile industry towards a more green and safe 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 advantages such as low cost, non-toxicity, safety, and renewability. For example, by adsorbing bio-based flavonoids and then performing mordanting treatment with metal salts, a composite is obtained which exhibits flame-retardant properties on silk fabric [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 fabric performs poorly in terms of wash durability.

[0005] Gallic acid (GA) is a naturally occurring polyphenol with a phenolic hydroxyl group structure, which endows it with various functions such as antibacterial, antioxidant, antiviral, and anti-inflammatory properties. The low cost and high reactivity of GA 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) were 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 flame retardants and cross-linkers for the fabrication of flame-retardant polyurethane elastomers, Chemistry Select 8(39) (2023) e202302496].

[0006] Amino-quinone network (AQN) coating method is a new development in the field of mussel-inspired chemistry in recent years. This method forms a self-crosslinking coating through 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 the durability of the resulting coating. Polyethyleneimine (PEI) is rich in reactive primary amino groups and can react with GA to form a self-crosslinking network. The AQN system can remove the hydration layer on the surface of the material, resulting in strong adhesion. In addition, studies have shown that nitrogen-modified polyphenols have good effects in reducing the peak heat release rate of cellulose fibers. This supports the application of AQN in textile flame retardation.

[0007] As a patent CN201910565152.9, a preparation method of formaldehyde-free and washing-resistant flame-retardant fabric, the fabric fixed after the natural polyphenol compound is placed in the metal salt solution for immersion and cooking, and a formaldehyde-free and washing-resistant flame-retardant fabric is obtained. However, during the preparation process, the fabric after deposition of the natural polyphenol compound is placed in the fixing agent solution for immersion and cooking, and the fixing agent solution is at least one of the following: cream of tartar solution, chitosan solution, fixing agent Y solution, and water-soluble polyurethane fixing agent solution. Among them, the free formaldehyde content of fixing agent Y is very high; the other three fixing agents all improve the flame retardant durability of the fabric by forming a film on the surface of the fabric, which affects the hand feeling of the fabric.

[0008] For example, patent CN201811270759.6, a kind of 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. But the limiting oxygen index of unwashed silk fabric is only 27.5%, the effect needs to be improved, and the treatment temperature of this method is high, and batch preparation has not been realized.

[0009] The disclosure of the above background art is only used to assist in understanding the inventive concept and technical solutions of the present application, and does not necessarily belong to the prior art of the present patent application. In the absence of explicit evidence that the above-mentioned content has been disclosed before the filing date of the present patent application, the above background art should not be used to evaluate the novelty and inventiveness of the present application. SUMMARY

[0010] Therefore, in order to overcome the defects of the prior art, the purpose of the present application is to provide an improved flame-retardant silk fabric with better durability.

[0011] To achieve the above-mentioned purpose, the present application adopts the following technical solutions:

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

[0013] Mixing gallic acid aqueous solution and polyethyleneimine aqueous solution uniformly, adding alkali solution to adjust the pH value to alkaline, to obtain finishing liquid;

[0014] Using the finishing liquid to perform first treatment on degummed silk fabric, to obtain silk fabric treated with finishing liquid;

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

[0016] Drying the flame-retardant finished silk fabric to obtain the flame-retardant silk fabric.

[0017] According to some preferred embodiments of the present application, the gallic acid aqueous solution is prepared by mixing gallic acid with deionized water at 40-60℃, so that the gallic acid is completely dissolved in the deionized water to obtain a gallic acid aqueous solution with a concentration of 5-10g / L.

[0018] According to some preferred embodiments of the present application, the polyethyleneimine aqueous solution is prepared by mixing polyethyleneimine with deionized water at 30-50℃, so that the polyethyleneimine is completely dissolved in the deionized water to obtain a polyethyleneimine aqueous solution with a concentration of 5-50g / L.

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

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

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

[0022] According to some preferred embodiments of the present application, 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 5g / L-50g / L.

[0023] According to some preferred embodiments of the present application, the first treatment is: adding the finishing liquid into the dyeing tank of the jig dyeing machine, heating to 35-50℃, and winding the degummed silk fabric on the cloth roll through the dyeing tank, to obtain the silk fabric treated by the finishing liquid after jig dyeing; and the bath ratio during jig dyeing is 1:3-1:5.

[0024] According to some preferred embodiments of the present application, the second treatment is: adding the aqueous multivalent metal salt solution into the dyeing tank of the jig dyeing machine, heating to 40-60℃, and moving the silk fabric treated by the finishing liquid into the jig dyeing machine, to obtain the flame-retardant finished silk fabric after jig dyeing; and the bath ratio during jig dyeing is 1:3-1:5.

[0025] According to some preferred embodiments of the present application, the drying temperature is 50-90℃, and the drying time is 20-40 minutes.

[0026] In some embodiments of the present application, the method for preparing the durable flame-retardant silk fabric comprises the following steps:

[0027] (1) Preparation of the finishing liquid

[0028] Mixing the gallus acid with deionized water at 40-60℃ to completely dissolve the gallus acid in the deionized water, to obtain the aqueous gallus acid solution with a concentration of 5g / L-10g / L.

[0029] Mixing the polyethyleneimine with deionized water at 30-50℃ to completely dissolve the polyethyleneimine in the deionized water, to obtain the aqueous polyethyleneimine solution with a concentration of 5g / L-50g / L.

[0030] Mixing the aqueous gallus acid solution and the aqueous polyethyleneimine solution uniformly at a volume ratio of 1:2-1:4, adding the alkali solution to adjust the pH value to 8-10, to obtain the finishing liquid.

[0031] (2) Finishing of the fabric

[0032] The finishing liquid is added to the dyeing tank of the jig dyeing machine, and the temperature is raised to 35-50℃. The degummed silk fabric is wound on the cloth roller in the dyeing tank at a bath ratio of 1:3-1:5, the rotating speed of the jig dyeing machine is 5-10 m / min, and the silk fabric is dyed for 2 passes and washed for 1 pass, and then taken out of the machine to obtain the silk fabric treated with the finishing liquid.

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

[0034] In another jig dyeing machine, a solution of a polyvalent metal salt with a concentration of 5-50 g / L is prepared, and the temperature is raised to 40-60℃. The polyvalent metal salt is one or more selected from ferrous sulfate, ferric sulfate, aluminum sulfate and titanium sulfate.

[0035] (4) Treatment with the metal salt

[0036] The silk fabric treated with the finishing liquid is moved to the jig dyeing machine containing the solution of the polyvalent metal salt, and the rotating speed of the jig dyeing machine is 5-10 m / min, the bath ratio during dyeing is 1:3-1:5, and after 2 passes and 3 passes of washing, the silk fabric is taken out of the machine to obtain the flame-retardant finished silk fabric.

[0037] (5) Drying

[0038] The flame-retardant finished silk fabric is moved to an oven, dried at 50-90℃ for 20-40 min to obtain the durable flame-retardant silk fabric.

[0039] The application also provides a flame-retardant silk fabric prepared by the preparation method, which comprises a silk fabric and a coating layer on the surface of the silk fibers, and the coating layer is formed by the reaction of gallic acid with polyethylene imine and a polyvalent metal salt.

[0040] The principle of the application is that a durable flame retardant is obtained for silk fabric by combining gallic acid (GA), polyethylene imine (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 a PEI-GA / Me flame retardant system, thereby endowing the silk fabric with durable flame retardant properties.

[0041] The specific flame-retardant mechanism is that GA and PEI first decompose to generate non-flammable gases (such as H2O, NH3 and CO2), which dilutes the combustible gas and oxygen, and at the same time, takes away the heat generated by combustion. In addition, the catechol group in GA exhibits strong radical scavenging ability. During the combustion process, it can capture highly active radicals (H· and OH·), interrupt the combustion reaction, thereby providing a gas-phase flame-retardant effect. At the same time, the metal ions and catechol groups synergistically act in the condensed phase to accelerate the formation of a dense carbon layer. The metal ions combine with oxygen to form metal oxides, which are uniformly distributed on the surface of the residual carbon, making the carbon layer more dense and stable. The carbon layer can prevent heat and oxygen from entering the silk matrix, increase the amount of residual carbon, and reduce the further thermal degradation of the matrix. Therefore, the PEI-GA / Me system synergistically acts in the gas phase and the condensed phase, so that the silk fabric has excellent flame-retardant properties. Among them, GA has strong chelating ability, which acts with metal ions through coordination bonds and forms a ternary complex with silk to improve the wash resistance of the fabric. In addition, the silk fabric treated by GA and Fe3+ complex also has excellent antibacterial performance.

[0042] Compared with the prior art, the preparation method of the flame-retardant silk fabric of the present application has the following advantages: the PEI-GA / Me flame-retardant system obtained by the method provides excellent and stable flame-retardant properties for silk fabric, overcoming the defect of poor 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 saving and emission reduction; the preparation method has low processing temperature and simple operation, and batch production is realized by using the roll dyeing method; the fabric integrates flame retardation and antibacterial performance, 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 washes, an LOI value higher than 27%, and good flame-retardant stability; the antibacterial performance against Staphylococcus aureus is 99.8%, and the hand feeling of the fabric does not change. BRIEF DESCRIPTION OF DRAWINGS

[0043] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings needed in the embodiment description. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0044] Figure 1 The vertical burning test photos and damage carbon length and LOI value of the durable flame-retardant silk fabric prepared in Examples 1-4 and the silk as received (untreated silk fabric);

[0045] Figure 2The vertical burning test photos and damaged char length and LOI values of the durable flame-retardant silk fabric prepared in Example 1-4 of the present application after 20 times of washing;

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

[0047] Figure 4 The antibacterial performance photos of the durable flame-retardant silk fabric prepared in Example 2 of the present application and untreated silk fabric. DETAILED DESCRIPTION

[0048] In order for those skilled in the art to better understand the technical solutions of the present application, the technical solutions in the embodiments of the present application will be described clearly and completely below in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor should belong to the protection scope of the present application.

[0049] The durable flame-retardant silk fabric and the preparation method thereof of the present application successfully apply the flame-retardant and antibacterial coating without phosphorus and halogen to silk fabric under mild conditions through simple pad dyeing and drying process. The preparation process of the present application is simple, and the adopted pad dyeing process is low in bath ratio, saves cost, and the silk fabric is not easy to wrinkle. The present application provides a new strategy for preparing durable and multifunctional flame-retardant silk by using renewable biomass resources. Specifically, the preparation method of the durable flame-retardant silk fabric of the present application takes silk fabric as a base material, and includes the following steps:

[0050] The durable flame-retardant silk fabric and the preparation method thereof of the present application successfully apply the flame-retardant and antibacterial coating without phosphorus and halogen to silk fabric under mild conditions through simple pad dyeing and drying process. The preparation process of the present application is simple, and the adopted pad dyeing process is low in bath ratio, saves cost, and the silk fabric is not easy to wrinkle. The present application provides a new strategy for preparing durable and multifunctional flame-retardant silk by using renewable biomass resources. Specifically, the preparation method of the durable flame-retardant silk fabric of the present application takes silk fabric as a base material, and includes the following steps:

[0051] (1) Preparation of finishing liquid

[0052] Gallic acid is mixed with deionized water at 40-60 DEG C to make the gallic acid completely dissolved in the deionized water, and a gallic acid aqueous solution with a concentration of 5-10 g / L is obtained.

[0053] Polyethyleneimine is mixed with deionized water at 30-50 DEG C to make the polyethyleneimine completely dissolved in the deionized water, and a polyethyleneimine aqueous solution with a concentration of 5-50 g / L is obtained. The Mw molecular weight of the polyethyleneimine is 500-5000.

[0054] Mix the gallic acid aqueous solution and the polyethyleneimine aqueous solution in a volume ratio of 1:2 to 1:4, add a lye to adjust the pH value to 8 to 10 to obtain a finishing liquid. The lye is a 5 g / L to 20 g / L sodium hydroxide solution.

[0055] (2) Finishing of the fabric

[0056] Add the finishing liquid to the dyeing tank of a jigger, heat to 35°C to 50°C, and pass the degummed silk fabric through the dyeing tank to be wound on the cloth roll in a bath ratio of 1:3 to 1:5, with the jigger rotating at 5 to 10 meters / minute, and reciprocating 2 times, 1 time of washing, and then taken out of the machine to obtain the silk fabric treated with the finishing liquid.

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

[0058] In another jigger, prepare a 5 g / L to 50 g / L aqueous solution of a polyvalent metal salt, and heat 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 with the metal salt

[0060] Move the silk fabric treated with the finishing liquid to the jigger with the polyvalent metal salt solution, and rotate the jigger at 5 to 10 meters / minute, reciprocate 2 times, 3 times of washing, and then taken out of the machine to obtain the flame-retardant finished silk fabric; the bath ratio during jiggering is 1:3 to 1:5.

[0061] (5) Drying

[0062] Move the flame-retardant finished silk fabric to an oven, and dry at 50°C to 90°C for 20 to 40 minutes to obtain the durable flame-retardant silk fabric, which comprises the silk fabric and a coating layer on the surface, the coating layer being formed by the reaction of gallic acid with polyethyleneimine and the polyvalent metal salt, the PEI and GA forming a self-crosslinking network through Schiff base reaction or Michael addition, and further complexing with metal ions to construct a PEI-GA / Me flame-retardant system, thereby endowing the silk fabric with durable flame-retardant properties.

[0063] Example 1

[0064] The preparation method of the durable flame-retardant silk fabric in this example (ferrous sulfate, Fe 2+ ), and the specific steps are as follows:

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

[0066] (2) Finishing of the fabric: The finishing liquor is added to the dyeing tank of the jig dyeing machine, and the temperature is raised to 50°C. The degummed silk fabric is wound on the cloth roller by passing through the dyeing tank at a liquor ratio of 1 :4, and the rotation speed of the jig dyeing machine is 10 m / min. After 2 passes, 1 pass of washing is performed, and the fabric is taken out of the machine to obtain the silk fabric treated with the finishing liquor.

[0067] (3) Preparation of the solution of the polyvalent metal salt: In another jig dyeing machine, a ferrous sulfate aqueous solution is prepared at a concentration of 20 g / L, and the temperature is raised to 50°C.

[0068] (4) Treatment with the metal salt: The silk fabric treated with the finishing liquor obtained in step (2) above is moved to the jig dyeing machine, and the liquor ratio is 1 :4. The rotation speed of the jig dyeing machine is 10 m / min. After 2 passes, 3 passes of washing are performed, and the fabric is taken out of the machine to obtain the flame-retardant finished silk fabric.

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

[0070] Example 2

[0071] The method for preparing the durable flame-retardant silk fabric in this example (ferric sulfate, Fe 3 +) is as follows:

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

[0073] (2) Finishing of the fabric: The finishing liquor is added to the dyeing tank of the jig dyeing machine, and the temperature is raised to 40°C. The degummed silk fabric is immersed in the finishing liquor at a liquor ratio of 1 :5, and the rotation speed of the jig dyeing machine is 5 m / min. After 2 passes, 1 pass of washing is performed, and the fabric is taken out of the machine to obtain the silk fabric treated with the finishing liquor.

[0074] (3) Preparation of the solution of the polyvalent metal salt: In another jig dyeing machine, a ferric sulfate aqueous solution is prepared at a concentration of 10 g / L, and the temperature is raised to 40°C.

[0075] (4) Treatment with the metal salt: The silk fabric treated with the finishing liquor obtained in step (2) above is moved to the jig dyeing machine, and the liquor ratio is 1 :5. The rotation speed of the jig dyeing machine is 5 m / min. After 2 passes, 3 passes of washing are performed, and the fabric is taken out of the machine to obtain the flame-retardant finished silk fabric.

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

[0077] Example 3

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

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

[0080] (2) Fabric finishing: the finishing solution is added to the dyeing tank of the jigger, heated to 60°C, and the degummed silk fabric is immersed in the finishing solution at a bath ratio of 1:4, the jigger speed is 5 meters / minute, 2 passes, 1 water washing, and the machine is taken out to obtain the finishing solution treated silk fabric.

[0081] (3) Configuration of polyvalent metal salt solution: in another jigger, aluminum sulfate aqueous solution is configured, the concentration is 10 g / L, and the temperature is raised to 60°C.

[0082] (4) Metal salt treatment: the finishing solution treated silk fabric obtained in the above step (2) is moved to the above jigger, the bath ratio is 1:4, the jigger speed is 5 meters / minute, 2 passes, and then 3 water washings are used, the machine is taken out, and the flame retardant finished silk fabric is obtained.

[0083] (5) Drying: the above flame retardant finished silk fabric is moved to the drying room, dried at 60°C for 20 minutes, and the durable flame retardant silk fabric is obtained.

[0084] Example 4

[0085] Preparation method of durable flame retardant silk fabric (titanium sulfate, Ti 4 +) in this example, the specific steps are as follows:

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

[0087] (2) Fabric finishing: the finishing solution is added to the dyeing tank of the jigger, heated to 50°C, and the degummed silk fabric is immersed in the finishing solution at a bath ratio of 1:3, the jigger speed is 10 meters / minute, 2 passes, 1 water washing, and the machine is taken out to obtain the finishing solution treated silk fabric.

[0088] (3) Configuration of polyvalent metal salt solution: in another jigger, titanium sulfate aqueous solution is configured, the concentration is 10 g / L, and the temperature is raised to 50°C.

[0089] (4) Metal salt treatment: The silk fabric treated with the finishing solution obtained in step (2) above was moved to the jig dyeing machine, bath ratio was 1:3, the rotation speed of the jig dyeing machine was 10 meters / minute, after 2 reciprocations, 3 water washes were used, and the machine was taken out, obtaining the flame-retardant finished silk fabric.

[0090] (5) Drying: The flame-retardant finished silk fabric above was moved to the drying room, dried at 50°C for 30 minutes, obtaining the durable flame-retardant silk fabric.

[0091] Test and results

[0092] The flame-retardant performance of the silk fabric prepared in the embodiments of the present application was determined according to GB / T 5454-1997 "Textile Burning Performance Experiment Oxygen Index Method" and GB / T 5455-2014 "Textile Burning Performance Vertical Damage Length, Smoldering and Afterburning Time Determination". The washing method of the flame-retardant silk fabric was performed according to GB / T 3921-2008 "Textile Color Fastness Test Soap Washing Color Fastness" standard, using 2g / L of silk and wool fabric special detergent, bath ratio 1:50, washing at 40°C for 30 minutes as one time. The washing was repeated to the required number of times.

[0093] (1) Flame-retardant test

[0094] The vertical burning test photos and damage carbon length and LOI value results of the durable flame-retardant silk fabrics prepared in Examples 1-4 and the silk sample (untreated silk fabric) are shown in Figure 1 .

[0095] As can be seen from Figure 1 , the untreated silk fabric burns rapidly after contacting the flame, and is completely burnt in 12 seconds, almost the entire sample (30 centimeters) is burnt. In contrast, the treated fabric self-extinguishes rapidly after contacting the flame, the spread of the flame is completely inhibited, and the fabric carbonizes at high temperature. The damage length of the fabrics treated with Fe 2+ , Fe 3+ , Al 3+ and Ti 4+ is 9.2 centimeters, 8.3 centimeters, 9.3 centimeters and 8.2 centimeters respectively, which is significantly shorter than that of the untreated silk fabric. It shows that the flame-retardant performance of the treated silk fabric has been significantly improved, reaching the B1 level flame-retardant standard, according to the Chinese standard GB / T17591, the B1 level flame-retardant requires the carbonization length to be less than 15 centimeters.

[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 untreated silk. This 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 the combustion process.

[0097] (2) Durability test

[0098] 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.

[0099] 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.

[0100] For Fe 3+ The ion-treated fabric (Example 2) underwent more washing tests, such as... Figure 3 (As shown in Example 2, the vertical burning char length and LOI test results of the durable flame-retardant silk fabric before and after washing) indicate 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 demonstrate that modifying silk fabrics through the co-deposition of GA, PEI, and metal ions can effectively improve their flame retardancy and washability.

[0101] (3) Antibacterial test

[0102] Figure 4 Photographs 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 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.

[0104] The application discloses durable flame-retardant silk fabrics and a preparation method thereof, and belongs to the field of functional finishing of textiles. The preparation steps are as follows: gallic acid (GA), polyethylene imine (PEI) and metal ions are combined, and flame-retardant silk fabrics are prepared through a simple pad-dry method. The silk fabrics modified by different metal ions (Fe 2+ , Fe 3+ , Al 3+ and Ti 4+ all exhibit self-extinguishing characteristics in the vertical burning test, and the damage coke lengths are 9.2 cm, 8.3 cm, 9.3 cm and 8.2 cm, respectively, and the limiting oxygen index (LOI) values are 29.8%, 30.2%, 27.4% and 33.0%, respectively. After 50 washing cycles, the damage coke length of the silk treated by Fe 3+ is still kept below 15 cm. The silk treated by Fe 3+ also exhibits excellent antibacterial performance. The simple and environmentally-friendly functional silk fabric preparation method in the application provides a new way for developing advanced and sustainable silk textiles.

[0105] The above examples are only for illustrating the technical concept and characteristics of the application, and the purpose is to enable those skilled in the art to understand the content of the application and implement it, and cannot limit the protection scope of the application, and equivalent changes or modifications made according to the spirit and essence of the application should be covered in the protection scope of the application.

[0106] The endpoints of the ranges and any values in the ranges disclosed herein are not limited to the precise values. The ranges should be interpreted as being inclusive of values adjacent to the recited ranges. For values having a range, the endpoints of the ranges are included in the range. The ranges should be interpreted as being inclusive of the endpoints.

Claims

1. A process for the preparation of flame retardant silk fabric, characterized in that, The method comprises the following steps: a gallic acid aqueous solution and a polyethyleneimine aqueous solution are mixed uniformly, and a lye is added to adjust the pH value to alkaline to obtain a finishing liquid; the degummed silk fabric is treated with the finishing liquid for the first time to obtain a silk fabric treated with the finishing liquid; a multivalent metal salt solution is prepared, and the silk fabric treated with the finishing liquid is treated with the multivalent metal salt solution for the second time to obtain a flame-retardant finished silk fabric; the flame-retardant finished silk fabric is dried to obtain the flame-retardant silk fabric. The multivalent metal salt is one or more selected from ferrous sulfate, ferric sulfate, aluminum sulfate and titanium sulfate.

2. The production method according to claim 1, characterized by, The gallic acid aqueous solution is prepared by mixing gallic acid with deionized water at 40-60 ℃ to completely dissolve the gallic acid in the deionized water to obtain a gallic acid aqueous solution with a concentration of 5-10 g / L.

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

4. The method of claim 1, wherein, The volume ratio between the gallic acid aqueous solution and the polyethyleneimine aqueous solution is 1:2-1:

4.

5. The production method according to claim 1, characterized by, The lye is a sodium hydroxide solution with a concentration of 5-20 g / L, and the pH value of the finishing liquid is 8-10.

6. The production method according to claim 1, characterized by, The concentration of the multivalent metal salt solution is 5-50 g / L.

7. The production method according to claim 1, characterized by, The first treatment is that the finishing liquid is added to a dye tank of a jigger, the temperature is raised to 35-50 ℃, the degummed silk fabric is wound on a cloth roller through the dye tank, and the silk fabric treated with the finishing liquid is obtained after jigger dyeing.

8. The production method according to claim 1, characterized by, The second treatment is that the metal salt aqueous solution is added to a dye tank of a jigger, the temperature is raised to 40-60 ℃, the silk fabric treated with the finishing liquid is moved to the jigger, and the flame-retardant finished silk fabric is obtained after jigger dyeing.

9. The method of claim 1, wherein, The drying temperature is 50-90 ℃, and the time is 20-40 minutes.

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

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