A flame-retardant thermal-insulation layered composite fabric and a preparation method thereof

Abstract

This invention relates to the field of layered materials technology, and discloses a flame-retardant and heat-insulating layered composite fabric and its preparation method. The preparation method of the flame-retardant and heat-insulating layered composite fabric includes the following steps: blending soybean fiber, modified cotton fiber, and carbon fiber into yarn, and weaving to obtain an inner layer fabric; blending modified aramid 1313 fiber, cotton fiber, and polytetrafluoroethylene fiber into yarn, and weaving to obtain an outer layer fabric; immersing the outer layer fabric in a modified aerogel treatment agent to obtain a functionalized outer layer fabric; coating one side of the functionalized outer layer fabric with a polyurethane adhesive, bonding it to the inner layer fabric, and hot-pressing to obtain the flame-retardant and heat-insulating layered composite fabric. The flame-retardant and heat-insulating layered composite fabric of this invention not only has excellent flame-retardant and heat-insulating properties, but also possesses good antistatic, antibacterial, anti-corrosion, water- and oil-repellent, moisture-wicking, breathable, and skin-friendly properties.

Description

Technical Field

[0001] This invention relates to the field of layered materials technology, specifically to a flame-retardant and heat-insulating layered composite fabric and its preparation method. Background Technology

[0002] The market offers a wide variety of clothing fabrics, each with different functional requirements due to varying usage scenarios. Flame-retardant and heat-insulating fabrics have broad application prospects in production and daily life. For example, in daily life, they can be processed into heat-insulating gloves, and in industrial production, they can be used in high-temperature environments in industries such as semiconductors, biopharmaceuticals, optical instruments, and food. For instance, Chinese patent application CN116353159A provides a flame-retardant polyester fabric comprising a polyester fabric layer and a flame-retardant composite layer. The flame-retardant composite layer includes a flame-retardant layer, a carbon layer, and a heat-insulating layer. The flame-retardant layer is a polyurethane flame-retardant layer, the carbon layer is a lignin gel layer, and the heat-insulating layer is an electrospun layer containing silica nanospheres. However, the flame-retardant and heat-insulating properties of this flame-retardant polyester fabric still need improvement. Furthermore, the lack of antistatic and antibacterial properties also limits its application. Summary of the Invention

[0003] To address the aforementioned technical problems, this invention provides a method for preparing a flame-retardant and heat-insulating layered composite fabric, comprising the following steps:

[0004] Step (1): Cotton fibers are sequentially treated with sodium periodate aqueous solution and a modified mixture containing 2-amino-2'-hydroxy-1,1'-dinaphthalene to obtain surface-modified cotton fibers;

[0005] Step (2): Phase change microcapsules are prepared using ethyl cellulose and coconut oil as raw materials; citric acid is used as a crosslinking agent to attach the phase change microcapsules to the surface-modified cotton fibers to obtain modified cotton fibers.

[0006] Step (3): Blend soybean fiber, modified cotton fiber, and carbon fiber into yarn, and weave to obtain the inner fabric; blend modified aramid 1313 fiber, cotton fiber, and polytetrafluoroethylene fiber into yarn, and weave to obtain the outer fabric.

[0007] The preparation method of modified aramid 1313 fiber includes the following steps:

[0008] Step A1: Tetraethylenepentamine reacts with methyl acrylate to obtain a polyamine polymer;

[0009] Step A2: Pre-treat the aramid 1313 fiber to obtain pre-treated aramid 1313 fiber; treat the pre-treated aramid 1313 fiber with a polyamine polymer mixture, treat with silver nitrate aqueous solution, and steam treatment to obtain modified aramid 1313 fiber.

[0010] Step (4): Immerse the outer fabric in the modified aerogel treatment agent to obtain the functionalized outer fabric; coat one side of the functionalized outer fabric with polyurethane adhesive, bond it with the inner fabric, and hot press it to obtain the flame-retardant and heat-insulating layered composite fabric.

[0011] The preparation method of the modified aerogel includes the following steps:

[0012] Step B1: Boric acid reacts with vinyltrimethoxysilane to obtain boron-doped silane; para-ester, 4-mercaptobenzaldehyde, and DOPO react to obtain a flame retardant modifier.

[0013] Step B2: Extract cannabis fiber from cannabis stems, and then crosslink it with chitosan and boron-doped silane to prepare aerogel powder;

[0014] Step B3: Modify the aerogel powder with a flame retardant modifier to obtain modified aerogel.

[0015] Preferably, in step (1), the method for preparing the surface-modified cotton fiber is as follows:

[0016] In a nitrogen atmosphere, under stirring conditions of 150-250 r / min, cotton fibers were mixed with a sodium periodate aqueous solution of concentration of 0.02 g / mL at a mass ratio of 1:(40-60), and reacted in the dark at 30-40℃ for 1.5-2.5 h. After filtration, washing, and drying, pretreated cotton fibers were obtained.

[0017] Pretreated cotton fibers were mixed with a modified mixture at a mass ratio of 1:(40-60), reacted at 58-63℃ for 3-4 hours, filtered, washed, and dried to obtain surface-modified cotton fibers. The modified mixture was obtained by mixing 2-amino-2'-hydroxy-1,1'-dinaphthalene and methanol at a mass ratio of (2.8-5.6):(80-100) and ultrasonically treating for 10-20 minutes.

[0018] In the above process, after the cotton fiber is oxidized by sodium periodate, some of the hydroxyl groups on the surface are converted into aldehyde groups. The aldehyde groups then undergo a Schiff base reaction with the amino group of 2-amino-2'-hydroxy-1,1'-dinaphthalene, introducing a binaphthalene structure with heat insulation and cooling capabilities onto the surface of the cotton fiber.

[0019] Preferably, in step (2), the method for preparing the modified cotton fiber is as follows:

[0020] Coconut oil is melted by heating at 50-60℃ for 5-10 minutes, then mixed with a 1 wt% polyvinyl alcohol aqueous solution, and stirred at 1400-1600 r / min for 10-20 minutes. Then, an 18.6 wt% ethyl cellulose / acetone solution is added dropwise at a rate of 1-1.5 mL / min, and stirred at 800-1000 r / min for 2-3 hours at 32-38℃ to obtain phase change microcapsules. The mass ratio of coconut oil, polyvinyl alcohol aqueous solution, and ethyl cellulose / acetone solution is (5-10):(5-10):(15-40).

[0021] Phase change microcapsules were added to deionized water and sonicated for 10-20 min. Surface-modified cotton fibers were then added and stirred for 10-20 min. Citric acid and sodium hypophosphite were added, and the mixture was heated to 95-105℃ at a heating rate of 1.5-2.5℃ / min and held for 100-150 min. The mixture was then filtered, washed, and dried to obtain modified cotton fibers. The mass ratio of phase change microcapsules, deionized water, surface-modified cotton fibers, citric acid, and sodium hypophosphite was (2-3):300:(10-15):(6-10):(6-10).

[0022] In the above process, phase change microcapsules with coconut oil as the phase change core material and ethyl cellulose as the shell were prepared by solvent evaporation. Furthermore, using citric acid as a crosslinking agent, the phase change microcapsules were grafted onto cotton fibers through esterification reaction to obtain modified cotton fibers.

[0023] Preferably, in step (3), the mass ratio of soybean fiber, modified cotton fiber, and carbon fiber is (25-45):(56-76):(1-2), the yarn blended from them has an English count of 40-60S, and the weight of the inner fabric is 120-140g / m². 2 .

[0024] Preferably, in step (3), the mass ratio of the modified aramid 1313 fiber, cotton fiber, and polytetrafluoroethylene fiber is (30-40):(20-30):(30-40), the yarn blended from them has an English count of 40-60S, and the outer fabric has a weight of 140-160g / m². 2 .

[0025] Further, in step (3), the preparation method of the modified aramid 1313 fiber includes the following steps:

[0026] Step A1: In a nitrogen atmosphere, tetraethylenepentamine is placed in an ice-water bath, and a 34.2 wt% methyl acrylate / methanol solution is added dropwise at a rate of 0.8-1.2 mL / min under stirring. After the addition is complete, stirring is continued at room temperature for 3.5-4.5 h, the temperature is raised to 145-155℃, and the mixture is allowed to stand for 3.5-4.5 h to obtain a polyamine polymer; wherein the ratio of tetraethylenepentamine to methyl acrylate / methanol solution is (4.7-9.4) g:(7-14) mL.

[0027] In the above process, tetraethylenepentamine and methyl acrylate undergo Michael addition reaction and melt polycondensation to obtain a polyamine polymer;

[0028] Step A2: Add the washed aramid 1313 fibers to dichloromethane at a solid-liquid ratio of 4:(220-280), sonicate for 20-40 minutes, then remove and add to epichlorohydrin treatment solution at a solid-liquid ratio of 4:(240-260). Treat at 38-42℃ for 100-150 minutes, then remove and wash with deionized water and acetone until the pH of the washing solution is 7. Finally, treat with a 30-50 wt% sodium hydroxide aqueous solution at 75-85℃ for 100-150 minutes, then remove and dry to obtain pretreated aramid 1313 fibers; wherein, the epichlorohydrin treatment solution is obtained by mixing epichlorohydrin and aluminum chloride at a mass ratio of 40:25.

[0029] A polyamine polymer was added to deionized water to form a polyamine polymer mixture with a concentration of 0.5-2 g / L. Pretreated aramid 1313 fibers were added to the polyamine polymer mixture at a solid-liquid ratio of 1:(40-60). After treatment at 75-85℃ for 22-26 h, the fibers were removed, washed, and dried to obtain surface-modified aramid 1313 fibers. The surface-modified aramid 1313 fibers were then immersed in a silver nitrate aqueous solution with a concentration of 0.1-0.3 mol / L at a solid-liquid ratio of 1:(25-35) for 50-70 min, followed by steam treatment at 100℃ for 20-40 min, washing, and drying to obtain modified aramid 1313 fibers.

[0030] In the above process, aramid 1313 fibers undergo Friedel-Crafts alkylation to introduce epoxy groups on their surface. The epoxy groups then undergo ring-opening and react with the amino groups of the polyamino polymer, grafting the polyamino polymer onto the aramid 1313 fibers. Furthermore, the abundant amino groups and terminal primary amino groups in the polyamino polymer can effectively complex silver ions. Under hot steam conditions, some silver ions are reduced by the amino groups to form nano-silver and can effectively prevent the aggregation of nano-silver. The amino polymer plays a dual role as a complexing agent and a reducing agent.

[0031] Preferably, in step (4), the modified aerogel treatment agent is made of 1-3% (owf) modified aerogel and 10g / L sodium carbonate aqueous solution; the immersion treatment conditions are: the bath ratio of the outer fabric to the modified aerogel treatment agent is 1:(15-25), the immersion treatment time is 50-100min; the roll-off rate is 80%, and the fabric is first dried at 60-70℃ and then baked at 140-150℃ for 3-5min;

[0032] In the above process, the H atoms on the α-carbon of the para-ester structure introduced on the surface of the modified aerogel become active under alkaline conditions due to the electron-withdrawing effect of the sulfonation group, and are easily eliminated to form vinyl sulfonation. Under alkaline conditions, they undergo a covalent bonding reaction with the hydroxyl groups on the cotton fibers in the outer fabric, thereby grafting the modified aerogel onto the outer fabric.

[0033] Preferably, in step (4), the coating amount of the polyurethane adhesive is 18-22 g / m². 2 Hot pressing conditions: hot pressing for 20-40 seconds at a pressure of 0.15-0.2MPa and a temperature of 100-110℃.

[0034] Further, in step (4), the method for preparing the modified aerogel includes the following steps:

[0035] Step B1: Mix ethanol, 37.5 wt% hydrochloric acid aqueous solution, and vinyltrimethoxysilane, heat to reflux and stir for 20-24 h, then maintain the temperature of the mixture at 65-75℃, add boric acid, stir for 2-3 h, raise the temperature to 80-85℃, and continue stirring for 3-4 h to obtain boron-doped silane; wherein the mass ratio of ethanol, hydrochloric acid aqueous solution, vinyltrimethoxysilane, and boric acid is (8.6-17.2):(19.9-39.8):(0.7-1.4):(0.9-1.8);

[0036] In the above process, vinyltrimethoxysilane hydrolyzes to form silanol, which then condenses with the hydroxyl groups of boric acid to form boron-doped silane.

[0037] Step B2: Cut the hemp stems that have been peeled of their bast layers into 1-4 cm pieces, crush them, soak them in deionized water for 10-15 hours, then stir them in a 1 mol / L sodium hydroxide aqueous solution at 70-80℃ for 2-4 hours, and finally stir them in a 2 wt% sodium hypochlorite aqueous solution at 60-70℃ for 2-4 hours. Filter, wash, freeze dry to obtain hemp fiber.

[0038] A 0.1 wt% chitosan / acetic acid solution was mixed with a 1 wt% boron-doped silane aqueous solution, hemp fiber was added, the mixture was ultrasonically treated, and then freeze-dried at -80 to -75 °C and ground to obtain aerogel powder; wherein the mass ratio of chitosan acetic acid solution, boron-doped silane aqueous solution and hemp fiber was 100:(2-6):(0.003-0.005);

[0039] In the above process, chitosan, boron-doped silane, and hemp fiber crosslink to form an aerogel containing flame-retardant boron. The aerogel structure contains abundant amino, hydroxyl, and carbon-carbon double bonds.

[0040] Step B3: Add para-ester and 4-mercaptobenzaldehyde to dimethyl sulfoxide, sonicate at 40-45℃ for 40-60 min, then raise the temperature to 60-70℃ and react for 3-4 h. Add DOPO, raise the temperature to 80-90℃ and continue the reaction for 4-5 h. Cool to room temperature, centrifuge, wash, and dry to obtain the flame retardant modifier. The mass ratio of para-ester, 4-mercaptobenzaldehyde, dimethyl sulfoxide, and DOPO is (14-28):(6.9-13.8):(500-600):(10.8-21.6).

[0041] In the above process, the amino group of the para-ester reacts with the aldehyde group of 4-mercaptobenzaldehyde to form a Schiff base reaction to form a C=N bond. The C=N bond then undergoes an addition reaction with the active hydrogen of DOPO to form a flame retardant modifier containing nitrogen and phosphorus elements. The flame retardant modifier contains a mercapto group and a para-ester structure.

[0042] Aerogel powder was added to N,N-dimethylformamide and ultrasonically dispersed for 20-40 min. The mixture was then heated to 50-80℃, followed by the addition of flame retardant modifier and azobisisobutyronitrile. The mixture was stirred and reacted for 3-5 h. After the reaction was completed, the mixture was centrifuged, washed, and dried to obtain the modified aerogel. The mass ratio of aerogel powder, N,N-dimethylformamide, flame retardant modifier, and azobisisobutyronitrile was (3-5):(120-150):(1-1.5):(0.2-0.3).

[0043] In the above process, the carbon-carbon double bonds on the surface of the aerogel combine with the mercapto groups in the flame retardant modifier through a thiol olefin click reaction to obtain the modified aerogel.

[0044] The flame-retardant and heat-insulating layered composite fabric prepared by the aforementioned method is described.

[0045] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0046] The flame-retardant and heat-insulating layered composite fabric of this invention is composed of a functionalized outer layer fabric and an inner layer fabric. The functionalized outer layer fabric is made from modified aramid 1313 fiber, cotton fiber, and polytetrafluoroethylene fiber in a specific ratio, and then treated with a modified aerogel agent. Aramid 1313 fiber has excellent flame retardancy, but due to its extremely high bulkiness, it is prone to static electricity during spinning. Through modification treatment, nano-silver is deposited in situ on its surface, giving the aramid 1313 fiber antistatic and antibacterial properties, reducing the processing difficulty during spinning, and giving the outer layer fabric durable antistatic and antibacterial properties. The polytetrafluoroethylene fiber… Ethylene fiber possesses excellent high-temperature resistance, chemical corrosion resistance, and water and oil repellency, giving the outer fabric permanent water and oil repellency and corrosion resistance. After the outer fabric is treated with a modified aerogel agent, modified aerogel is covalently loaded onto its surface. The porous network characteristics of the aerogel give it excellent thermal insulation properties, and the nitrogen, phosphorus, and boron elements in the modified aerogel work synergistically to exert a significant flame-retardant effect. Therefore, the functionalized outer fabric has excellent flame-retardant and thermal insulation properties, antistatic properties, antibacterial properties, corrosion resistance, and water and oil repellency.

[0047] The inner layer of the flame-retardant and heat-insulating layered composite fabric is made of soybean fiber, modified cotton fiber, and carbon fiber in a specific ratio. Soybean fiber has a cashmere-like soft feel and is superior to cotton in terms of warmth and skin-friendliness. The addition of carbon fiber helps improve the antistatic properties of the inner layer fabric. Cotton fiber has excellent skin-friendliness and moisture absorption and breathability. After modification treatment, a naphthalene structure with heat insulation and cooling capabilities and phase change microcapsules are introduced on its surface, which can better absorb the residual heat that penetrates the fabric. Therefore, the inner layer fabric has excellent heat insulation, antistatic, moisture absorption and breathability, and skin-friendliness.

[0048] In summary, the flame-retardant and heat-insulating layered composite fabric composed of the inner layer fabric and the functionalized outer layer fabric of this invention not only has excellent flame-retardant and heat-insulating properties, but also has good antistatic, antibacterial, anti-corrosion, water and oil repellency, moisture absorption and breathability, and skin-friendliness. Attached Figure Description

[0049] Figure 1 This is a process flow diagram of the preparation method of the flame-retardant and heat-insulating layered composite fabric of the present invention;

[0050] Figure 2 This is a comparison chart of the limiting oxygen index tests of the flame-retardant and heat-insulating layered composite fabrics prepared in Examples 3-5 and Comparative Examples 3-9 of the present invention.

[0051] Figure 3 This is a comparison chart of the clo value tests of the flame-retardant and heat-insulating layered composite fabrics prepared in Examples 3-5 and Comparative Examples 3-9 of the present invention. Detailed Implementation

[0052] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0053] Example 1

[0054] This embodiment discloses a method for preparing modified aramid 1313 fiber, including the following steps:

[0055] Step A1: In a nitrogen atmosphere, 7.1 g of tetraethylenepentamine was placed in an ice-water bath, and 10.5 mL of methyl acrylate / methanol solution with a mass fraction of 34.2 wt% was added dropwise at a rate of 1 mL / min under stirring. After the addition was completed, stirring was continued at room temperature for 4 h, the temperature was raised to 150 °C, and the mixture was allowed to stand for 4 h to obtain the polyamine polymer.

[0056] Step A2: Add the washed aramid 1313 fibers to dichloromethane at a solid-liquid ratio of 4:250, sonicate for 30 minutes, then remove and add to epichlorohydrin treatment solution at a solid-liquid ratio of 4:250. Treat at 40°C for 120 minutes, then remove and wash with deionized water and acetone until the pH of the washing solution is 7. Finally, treat with a 40wt% sodium hydroxide aqueous solution at 80°C for 120 minutes, then remove and dry to obtain pretreated aramid 1313 fibers; wherein, the epichlorohydrin treatment solution is obtained by mixing epichlorohydrin and aluminum chloride at a mass ratio of 40:25.

[0057] A polyamine polymer was added to deionized water to form a polyamine polymer mixture with a concentration of 1.25 g / L. Pretreated aramid 1313 fibers were added to the polyamine polymer mixture at a solid-liquid ratio of 1:50. After treatment at 80℃ for 24 h, the fibers were removed, washed, and dried to obtain surface-modified aramid 1313 fibers. The surface-modified aramid 1313 fibers were then immersed in a 0.2 mol / L silver nitrate aqueous solution at a solid-liquid ratio of 1:30 for 60 min, followed by steam treatment at 100℃ for 30 min, washing, and drying to obtain modified aramid 1313 fibers.

[0058] Example 2

[0059] This embodiment discloses a method for preparing modified aerogel, including the following steps:

[0060] Step B1: Mix 12.9g ethanol, 29.9g hydrochloric acid aqueous solution with a mass fraction of 37.5wt%, and 1.1g vinyltrimethoxysilane, heat to reflux and stir for 22h, then maintain the temperature of the mixture at 70℃, add 1.4g boric acid, stir for 2.5h, raise the temperature to 83℃, and continue stirring for 3.5h to obtain boron-doped silane;

[0061] Step B2: Cut the hemp stems that have been peeled of their bast layers into 2cm pieces, crush them, soak them in deionized water for 12 hours, then stir them in a 1mol / L sodium hydroxide aqueous solution at 75°C for 3 hours, and finally stir them in a 2wt% sodium hypochlorite aqueous solution at 65°C for 3 hours. Filter, wash, freeze dry to obtain hemp fiber.

[0062] A 0.1 wt% chitosan / acetic acid solution was mixed with a 1 wt% boron-doped silane aqueous solution, hemp fiber was added, the mixture was ultrasonically treated, then freeze-dried at -78°C, and ground to obtain aerogel powder; wherein the mass ratio of chitosan acetic acid solution, boron-doped silane aqueous solution and hemp fiber was 100:4:0.004.

[0063] Step B3: Add 21g of para-ester and 10.4g of 4-mercaptobenzaldehyde to 550g of dimethyl sulfoxide, sonicate at 42℃ for 50min, then raise the temperature to 65℃ and react for 3.5h. Add 16.2g of DOPO, raise the temperature to 85℃ and continue the reaction for 4.5h. Cool to room temperature, centrifuge, wash, and dry to obtain the flame retardant modifier.

[0064] Add 4g of aerogel powder to 135g of N,N-dimethylformamide, sonicate for 30min, heat to 65℃, then add 1.2g of flame retardant modifier and 0.3g of azobisisobutyronitrile, stir and react for 4h. After the reaction is complete, centrifuge, wash and dry to obtain modified aerogel.

[0065] Example 3

[0066] This embodiment discloses a method for preparing a flame-retardant and heat-insulating layered composite fabric, including the following steps:

[0067] Step (1): In a nitrogen atmosphere, under stirring at 150 r / min, cotton fibers are mixed with a sodium periodate aqueous solution with a concentration of 0.02 g / mL at a mass ratio of 1:40. The mixture is reacted at 30°C in the dark for 2.5 h. After filtration, the mixture is ultrasonically washed three times with ethanol and deionized water in sequence, and then dried to obtain pretreated cotton fibers.

[0068] 2.8g of 2-amino-2'-hydroxy-1,1'-dinaphthalene was added to 80g of methanol and ultrasonically treated for 10min to obtain a modified mixture. The pretreated cotton fibers were mixed with the modified mixture at a mass ratio of 1:40 and reacted at 58℃ for 4h. The mixture was then filtered, washed, and dried to obtain surface-modified cotton fibers.

[0069] Step (2): Melt 5g of coconut oil at 50℃ for 10min, then mix it with 5-10g of 1wt% polyvinyl alcohol aqueous solution, stir at 1400r / min for 20min, then add 15g of 18.6wt% ethyl cellulose / acetone solution at 1mL / min, and stir at 800r / min for 3h at 32℃ to obtain phase change microcapsules;

[0070] Phase change microcapsules were added to deionized water and sonicated for 10 min. Surface-modified cotton fibers were then added and stirred for 10 min. Citric acid and sodium hypophosphite were added, and the mixture was heated to 95°C at a heating rate of 1.5°C / min and held for 150 min. The mixture was then filtered, washed, and dried to obtain modified cotton fibers. The mass ratio of phase change microcapsules, deionized water, surface-modified cotton fibers, citric acid, and sodium hypophosphite was 2:300:10:6:6.

[0071] Step (3): Mix soybean fiber, modified cotton fiber, and carbon fiber in a mass ratio of 25:56:1, and blend them into a yarn with an English count of 40S. Use this yarn as both warp and weft, and weave it to obtain a weight of 120g / m². 2 The inner fabric;

[0072] Modified aramid 1313 fiber, cotton fiber, and polytetrafluoroethylene fiber were mixed in a mass ratio of 30:20:30 and spun into a yarn with an English count of 40S. This yarn was then used as both warp and weft yarns and woven to obtain a weight of 140 g / m². 2 The outer fabric;

[0073] Step (4): Immerse the outer fabric in the modified aerogel treatment agent at a bath ratio of 1:15, soak for 50 minutes, remove and roll off excess water with a roll-off rate of 80%. First, dry at 60°C, then bake at 140°C for 5 minutes, remove and finally rinse with cold water, soap, wash with hot water, wash with cold water and dry to obtain the functionalized outer fabric; wherein, the modified aerogel treatment agent is made of 1% (owf = fabric weight) modified aerogel and 10g / L sodium carbonate aqueous solution;

[0074] One side of the functionalized outer fabric is coated with polyurethane adhesive at a coating amount of 18 g / m². 2The functionalized outer fabric coated with polyurethane adhesive is bonded to the inner fabric and hot-pressed for 40 seconds under a pressure of 0.15 MPa and a temperature of 100°C to obtain a flame-retardant and heat-insulating layered composite fabric.

[0075] Example 4

[0076] This embodiment discloses a method for preparing a flame-retardant and heat-insulating layered composite fabric, including the following steps:

[0077] Step (1): In a nitrogen atmosphere, under stirring at 250 r / min, cotton fibers are mixed with a sodium periodate aqueous solution with a concentration of 0.02 g / mL at a mass ratio of 1:60, reacted at 40°C in the dark for 1.5 h, filtered, and ultrasonically washed 5 times with ethanol and deionized water in sequence, and dried to obtain pretreated cotton fibers.

[0078] 5.6 g of 2-amino-2'-hydroxy-1,1'-dinaphthalene was added to 100 g of methanol and ultrasonically treated for 20 min to obtain a modified mixture. The pretreated cotton fibers were mixed with the modified mixture at a mass ratio of 1:60 and reacted at 63 °C for 3 h. The mixture was then filtered, washed, and dried to obtain surface-modified cotton fibers.

[0079] Step (2): Melt 10g of coconut oil at 60℃ for 5min, then mix it with 5-10g of 1wt% polyvinyl alcohol aqueous solution, stir at 1600r / min for 10min, then add 40g of 18.6wt% ethyl cellulose / acetone solution at 1.5mL / min, and stir at 1000r / min for 2h at 38℃ to obtain phase change microcapsules;

[0080] Phase change microcapsules were added to deionized water and sonicated for 20 min. Surface-modified cotton fibers were then added and stirred for 20 min. Citric acid and sodium hypophosphite were added, and the mixture was heated to 105℃ at a heating rate of 2.5℃ / min and held for 100 min. The mixture was then filtered, washed, and dried to obtain modified cotton fibers. The mass ratio of phase change microcapsules, deionized water, surface-modified cotton fibers, citric acid, and sodium hypophosphite was 3:300:15:10:10.

[0081] Step (3): Mix soybean fiber, modified cotton fiber, and carbon fiber in a mass ratio of 45:76:2, and blend them into a yarn with an English count of 60S. Use this yarn as both warp and weft, and weave it to obtain a weight of 140g / m². 2 The inner fabric;

[0082] Modified aramid 1313 fiber, cotton fiber, and polytetrafluoroethylene fiber were mixed in a mass ratio of 40:30:40 and spun into a yarn with an English count of 60S. This yarn was then used as both warp and weft yarns and woven to obtain a weight of 160 g / m². 2 The outer fabric;

[0083] Step (4): Immerse the outer fabric in the modified aerogel treatment agent at a liquor ratio of 1:25, soak for 100 minutes, remove and roll off excess water, with a roll-off rate of 80%. First, dry at 70°C, then bake at 150°C for 5 minutes, remove, and finally rinse with cold water, soap, wash with hot water, wash with cold water, and then dry to obtain the functionalized outer fabric; wherein, the modified aerogel treatment agent is made of 3% (owf) modified aerogel and 10g / L sodium carbonate aqueous solution;

[0084] One side of the functionalized outer fabric is coated with polyurethane adhesive at a coating amount of 22 g / m². 2 The functionalized outer fabric coated with polyurethane adhesive is bonded to the inner fabric and hot-pressed for 20 seconds under a pressure of 0.2 MPa and a temperature of 110°C to obtain a flame-retardant and heat-insulating layered composite fabric.

[0085] Example 5

[0086] This embodiment discloses a method for preparing a flame-retardant and heat-insulating layered composite fabric, including the following steps:

[0087] Step (1): In a nitrogen atmosphere, under stirring at 200 r / min, cotton fibers are mixed with a sodium periodate aqueous solution with a concentration of 0.02 g / mL at a mass ratio of 1:50. The mixture is reacted at 35°C in the dark for 2 h, filtered, and then ultrasonically washed 4 times with ethanol and deionized water in sequence. After drying, pretreated cotton fibers are obtained.

[0088] 4.2 g of 2-amino-2'-hydroxy-1,1'-dinaphthalene was added to 90 g of methanol and ultrasonically treated for 15 min to obtain a modified mixture. The pretreated cotton fibers were mixed with the modified mixture at a mass ratio of 1:50 and reacted at 60 °C for 3.5 h. The mixture was then filtered, washed, and dried to obtain surface-modified cotton fibers.

[0089] Step (2): Melt 7.5g of coconut oil at 55℃ for 8min, then mix it with 5-10g of 1wt% polyvinyl alcohol aqueous solution, stir at 1500r / min for 15min, then add 28g of 18.6wt% ethyl cellulose / acetone solution at 1.2mL / min, and stir at 900r / min for 2.5h at 35℃ to obtain phase change microcapsules;

[0090] Phase change microcapsules were added to deionized water and sonicated for 15 min. Surface-modified cotton fibers were then added and stirred for 15 min. Citric acid and sodium hypophosphite were added, and the mixture was heated to 100°C at a heating rate of 2°C / min and held for 120 min. The mixture was then filtered, washed, and dried to obtain modified cotton fibers. The mass ratio of phase change microcapsules, deionized water, surface-modified cotton fibers, citric acid, and sodium hypophosphite was 2.5:300:12.5:8:8.

[0091] Step (3): Mix soybean fiber, modified cotton fiber, and carbon fiber in a mass ratio of 35:66:1.5, and blend them into a yarn with an English count of 50S. Use this yarn as both warp and weft, and weave it to obtain a weight of 130g / m². 2 The inner fabric;

[0092] Modified aramid 1313 fiber, cotton fiber, and polytetrafluoroethylene fiber were mixed in a mass ratio of 35:25:35 and spun into a yarn with an English count of 50S. This yarn was then used as both warp and weft yarns and woven to obtain a weight of 150 g / m². 2 The outer fabric;

[0093] Step (4): Immerse the outer fabric in the modified aerogel treatment agent at a liquor ratio of 1:20, soak for 80 minutes, remove and roll off excess water, with a roll-off rate of 80%. First, dry at 65°C, then bake at 145°C for 4 minutes, remove, and finally rinse with cold water, soap, wash with hot water, wash with cold water, and then dry to obtain the functionalized outer fabric; wherein, the modified aerogel treatment agent is made of 2% (owf) modified aerogel and 10g / L sodium carbonate aqueous solution;

[0094] One side of the functionalized outer fabric is coated with polyurethane adhesive at a coating amount of 20 g / m². 2 The functionalized outer fabric coated with polyurethane adhesive is bonded to the inner fabric and hot-pressed for 30 seconds under a pressure of 0.18 MPa and a temperature of 105℃ to obtain a flame-retardant and heat-insulating layered composite fabric.

[0095] The modified aramid 1313 fiber and modified aerogel in Examples 3-5 above were prepared using the modified aramid 1313 fiber prepared in Example 1 and the modified aerogel prepared in Example 2, respectively.

[0096] Comparative Example 1

[0097] Compared with Example 2, in the preparation of aerogel powder, Comparative Example 1 used vinyltrimethoxysilane instead of boron-doped silane, while other conditions remained unchanged.

[0098] Comparative Example 2

[0099] Compared with Example 2, Comparative Example 2 did not add boron-doped silane during the preparation of aerogel powder. Therefore, the modified aerogel powder of this comparative example was obtained by simply mixing aerogel powder and flame retardant modifier, with all other conditions remaining unchanged.

[0100] Comparative Example 3

[0101] Compared with Example 5, in the process of preparing functionalized outer fabric, the modified aerogel in the modified aerogel treatment agent of Comparative Example 3 was the modified aerogel prepared in Comparative Example 1, and all other conditions remained unchanged.

[0102] Comparative Example 4

[0103] Compared with Example 5, in the process of preparing functionalized outer fabric, the modified aerogel in the modified aerogel treatment agent of Comparative Example 4 was the modified aerogel prepared in Comparative Example 2, and all other conditions remained unchanged.

[0104] Comparative Example 5

[0105] Compared with Example 5, Comparative Example 5 replaced the modified aerogel in the modified aerogel treatment agent with aerogel powder in the process of preparing the functionalized outer fabric, while keeping other conditions unchanged.

[0106] Comparative Example 6

[0107] Compared with Example 5, Comparative Example 6 replaced the modified aerogel in the modified aerogel treatment agent with a flame retardant modifier in the process of preparing the functionalized outer fabric, while keeping all other conditions unchanged.

[0108] Comparative Example 7

[0109] Compared with Example 5, Comparative Example 7 used aramid 1313 fiber instead of modified aramid 1313 fiber in the process of preparing the outer fabric, while keeping other conditions unchanged.

[0110] Comparative Example 8

[0111] Compared with Example 5, Comparative Example 8 used surface-modified cotton fibers instead of modified cotton fibers in the preparation of the inner layer fabric, while keeping other conditions unchanged.

[0112] Comparative Example 9

[0113] Compared with Example 5, Comparative Example 9 used pretreated cotton fibers instead of surface-modified cotton fibers in the process of preparing modified cotton fibers, while keeping other conditions unchanged.

[0114] In the above examples and comparative examples, polyvinyl alcohol with a molecular weight of 61,000 g / mol, branded as SigmaAldrich, was sourced from Beijing Bio-Innovation Technology Co., Ltd.; cotton fiber was Xinjiang long-staple cotton with a fiber length of 38-39 mm; aramid 1313 fiber with a fineness of 2D and a fiber length of 30 mm was sourced from DuPont, USA; polytetrafluoroethylene fiber with a specification of 1200D was sourced from Shanghai Fuding New Material Technology Co., Ltd.; soybean fiber with a length of 38 mm was sourced from Shanghai Guanqi Textile Co., Ltd.; carbon fiber with a length of 5 mm was purchased from Toray Industries, Japan; hemp stems (RHS) were obtained from a farmland; and polyurethane adhesive, model PU1179, with a viscosity of 200 cP, an acidity / alkalinity of 7.0-9.0, and a solids content of 37±1%, was sourced from Anhui Zhongen Chemical Co., Ltd.

[0115] Experimental Example

[0116] Test 1: Performance tests were conducted on the flame-retardant and heat-insulating layered composite fabrics prepared in Examples 3-5 and Comparative Examples 3-9.

[0117] 1. Antibacterial performance test: The antibacterial effect of each group of fabric samples against Escherichia coli and Staphylococcus aureus after 50 washes was tested according to GB / T 20944.3-2008 "Evaluation of antibacterial properties of textiles - Part 3: Vibration method".

[0118] 2. Flame retardant performance test: The limiting oxygen index shall be determined in accordance with GB / T5454 "Textiles - Test for flammability - Oxygen Index Method"; the afterflame time, smoldering time and damage length shall be determined in accordance with GB / T5455 "Textiles - Test for flammability - Vertical Method".

[0119] 3. Thermal insulation performance test: The clo value of the sample shall be determined in accordance with GB / T11048-2018 "Determination of thermal and moisture resistance of textiles under steady-state conditions for physiological comfort (evaporative hot plate method)".

[0120] 4. Antistatic performance test: The antistatic performance of each group of fabric samples after 50 washes was tested in accordance with GB / T12703.2-2009 "Evaluation of electrostatic properties of textiles - Part 2: Surface charge density".

[0121] The test results are shown in Table 1:

[0122] Table 1

[0123]

[0124] As shown in Table 1, the flame-retardant and heat-insulating layered composite fabrics prepared in Examples 3-5 of this invention exhibit excellent flame-retardant and heat-insulating properties, antibacterial properties, and antistatic properties. A comparison between Comparative Example 3 and Example 5 reveals that the boron element in the modified aerogel has a synergistic flame-retardant effect with the nitrogen and phosphorus elements, thus affecting the flame-retardant properties of the composite fabric. A comparison between Comparative Example 4 and Example 5 shows that the addition of boron-doped silane to the modified aerogel introduces flame-retardant boron elements, and the carbon-carbon double bonds in the silane facilitate the grafting of the flame-retardant modifier onto the aerogel, thereby affecting the grafting and dispersion of the aerogel onto the cotton fibers in the outer layer fabric. Therefore, the addition of borosilicate helps improve the flame-retardant and heat-insulating properties of the composite fabric. A comparison between Comparative Example 5 and Example 5 shows that the addition of the flame-retardant modifier to the modified aerogel introduces flame-retardant nitrogen and phosphorus elements, and, similar to Comparative Example 4, affects the grafting and dispersion of the aerogel onto the outer layer fabric. The grafting and dispersion of cotton fibers in the material affect the flame retardant and heat insulation performance of the composite fabric. A comparison between Comparative Example 6 and Example 5 shows that the porous network structure of the aerogel powder and the presence of boron improve the flame retardant and heat insulation performance of the composite fabric. A comparison between Comparative Example 7 and Example 5 shows that modifying aramid 1313 fibers imparts antistatic and antibacterial properties, resulting in durable antistatic and antibacterial properties for the composite fabric. A comparison between Comparative Examples 8-9 and Example 5 shows that modifying cotton fibers and introducing naphthalene structures with heat insulation and cooling capabilities, as well as phase change microcapsules, on their surface allows for better absorption of residual heat penetrating the fabric, thereby improving the heat insulation performance of the composite fabric.

[0125] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a flame-retardant and heat-insulating layered composite fabric, characterized in that, Includes the following steps: Step (1): Cotton fibers are sequentially treated with sodium periodate aqueous solution and a modified mixture containing 2-amino-2'-hydroxy-1,1'-dinaphthalene to obtain surface-modified cotton fibers; Step (2): Phase change microcapsules are prepared using ethyl cellulose and coconut oil as raw materials; citric acid is used as a crosslinking agent to attach the phase change microcapsules to the surface-modified cotton fibers to obtain modified cotton fibers. Step (3): Blend soybean fiber, modified cotton fiber, and carbon fiber into yarn, and weave to obtain the inner fabric; blend modified aramid 1313 fiber, cotton fiber, and polytetrafluoroethylene fiber into yarn, and weave to obtain the outer fabric. The preparation method of modified aramid 1313 fiber includes the following steps: Step A1: Tetraethylenepentamine reacts with methyl acrylate to obtain a polyamine polymer; Step A2: Pre-treat the aramid 1313 fiber to obtain pre-treated aramid 1313 fiber; treat the pre-treated aramid 1313 fiber with a polyamine polymer mixture, treat with silver nitrate aqueous solution, and steam treatment to obtain modified aramid 1313 fiber. Step (4): Immerse the outer fabric in the modified aerogel treatment agent to obtain the functionalized outer fabric; coat one side of the functionalized outer fabric with polyurethane adhesive, bond it with the inner fabric, and hot press it to obtain the flame-retardant and heat-insulating layered composite fabric. The preparation method of the modified aerogel includes the following steps: Step B1: Boric acid reacts with vinyltrimethoxysilane to obtain boron-doped silane; para-ester, 4-mercaptobenzaldehyde, and DOPO react to obtain a flame retardant modifier. Step B2: Extract cannabis fiber from cannabis stems, and then crosslink it with chitosan and boron-doped silane to prepare aerogel powder; Step B3: Modify the aerogel powder with a flame retardant modifier to obtain modified aerogel.

2. The method for preparing the flame-retardant and heat-insulating layered composite fabric according to claim 1, characterized in that, In step (1), the method for preparing the surface-modified cotton fiber is as follows: In a nitrogen atmosphere, under stirring conditions of 150-250 r / min, cotton fibers were mixed with a sodium periodate aqueous solution with a concentration of 0.02 g / mL at a mass ratio of 1:(40-60), and reacted in the dark at 30-40℃ for 1.5-2.5 h. After filtration, washing, and drying, pretreated cotton fibers were obtained. Pretreated cotton fibers and modified mixtures were mixed at a mass ratio of 1:(40-60) and reacted at 58-63℃ for 3-4 hours. The mixtures were then filtered, washed, and dried to obtain surface-modified cotton fibers. The modified mixtures were obtained by mixing 2-amino-2'-hydroxy-1,1'-dinaphthalene and methanol at a mass ratio of (2.8-5.6):(80-100) and then ultrasonically treating the mixtures for 10-20 minutes.

3. The method for preparing the flame-retardant and heat-insulating layered composite fabric according to claim 1, characterized in that, In step (2), the method for preparing the modified cotton fiber is as follows: Coconut oil is melted by heating at 50-60℃ for 5-10 minutes, then mixed with a 1 wt% polyvinyl alcohol aqueous solution, and stirred at 1400-1600 r / min for 10-20 minutes. Then, an 18.6 wt% ethyl cellulose / acetone solution is added dropwise at a rate of 1-1.5 mL / min, and stirred at 800-1000 r / min at 32-38℃ for 2-3 hours to obtain phase change microcapsules. The mass ratio of coconut oil, polyvinyl alcohol aqueous solution, and ethyl cellulose / acetone solution is (5-10):(5-10):(15-40). Phase change microcapsules were added to deionized water and sonicated for 10-20 min. Surface-modified cotton fibers were then added and stirred for 10-20 min. Citric acid and sodium hypophosphite were added, and the mixture was heated to 95-105℃ at a heating rate of 1.5-2.5℃ / min and held for 100-150 min. The mixture was then filtered, washed, and dried to obtain modified cotton fibers. The mass ratio of phase change microcapsules, deionized water, surface-modified cotton fibers, citric acid, and sodium hypophosphite was (2-3):300:(10-15):(6-10):(6-10).

4. The method for preparing the flame-retardant and heat-insulating layered composite fabric according to claim 1, characterized in that, In step (3), the mass ratio of soybean fiber, modified cotton fiber, and carbon fiber is (25-45):(56-76):(1-2), the yarn blended from them has an English count of 40-60S, and the weight of the inner fabric is 120-140g / m². 2 .

5. The method for preparing the flame-retardant and heat-insulating layered composite fabric according to claim 1, characterized in that, In step (3), the mass ratio of the modified aramid 1313 fiber, cotton fiber, and polytetrafluoroethylene fiber is (30-40):(20-30):(30-40), the yarn blended from them has an English count of 40-60S, and the outer fabric has a weight of 140-160g / m². 2 .

6. The method for preparing the flame-retardant and heat-insulating layered composite fabric according to claim 1, characterized in that, In step (3), the preparation method of the modified aramid 1313 fiber includes the following steps: Step A1: In a nitrogen atmosphere, tetraethylenepentamine is placed in an ice-water bath, and a 34.2 wt% methyl acrylate / methanol solution is added dropwise at a rate of 0.8-1.2 mL / min under stirring. After the addition is complete, stirring is continued at room temperature for 3.5-4.5 h, the temperature is raised to 145-155℃, and the mixture is allowed to stand for 3.5-4.5 h to obtain a polyamine polymer; wherein the ratio of tetraethylenepentamine to methyl acrylate / methanol solution is (4.7-9.4) g:(7-14) mL. Step A2: Add the washed aramid 1313 fibers to dichloromethane at a solid-liquid ratio of 4:(220-280), sonicate for 20-40 minutes, then remove and add to epichlorohydrin treatment solution at a solid-liquid ratio of 4:(240-260). Treat at 38-42℃ for 100-150 minutes, then remove and wash with deionized water and acetone until the pH of the washing solution is 7. Finally, treat with a 30-50 wt% sodium hydroxide aqueous solution at 75-85℃ for 100-150 minutes, then remove and dry to obtain pretreated aramid 1313 fibers; wherein, the epichlorohydrin treatment solution is obtained by mixing epichlorohydrin and aluminum chloride at a mass ratio of 40:

25. A polyamine polymer was added to deionized water to form a polyamine polymer mixture with a concentration of 0.5-2 g / L. Pretreated aramid 1313 fibers were added to the polyamine polymer mixture at a solid-liquid ratio of 1:(40-60). After treatment at 75-85℃ for 22-26 h, the fibers were removed, washed, and dried to obtain surface-modified aramid 1313 fibers. The surface-modified aramid 1313 fibers were then immersed in a silver nitrate aqueous solution with a concentration of 0.1-0.3 mol / L at a solid-liquid ratio of 1:(25-35) for 50-70 min, followed by steam treatment at 100℃ for 20-40 min, washing, and drying to obtain modified aramid 1313 fibers.

7. The method for preparing the flame-retardant and heat-insulating layered composite fabric according to claim 1, characterized in that, In step (4), the modified aerogel treatment agent is made of 1-3% modified aerogel and 10g / L sodium carbonate aqueous solution; the immersion treatment conditions are: the bath ratio of the outer fabric to the modified aerogel treatment agent is 1:(15-25), the immersion treatment time is 50-100min; the roll-off rate is 80%, and the fabric is first dried at 60-70℃ and then baked at 140-150℃ for 3-5min.

8. The method for preparing the flame-retardant and heat-insulating layered composite fabric according to claim 1, characterized in that, In step (4), the coating amount of the polyurethane adhesive is 18-22 g / m². 2 Hot pressing conditions: hot pressing for 20-40 seconds at a pressure of 0.15-0.2MPa and a temperature of 100-110℃.

9. The method for preparing the flame-retardant and heat-insulating layered composite fabric according to claim 1, characterized in that, In step (4), the method for preparing the modified aerogel includes the following steps: Step B1: Mix ethanol, 37.5 wt% hydrochloric acid aqueous solution, and vinyltrimethoxysilane, heat to reflux and stir for 20-24 h, then maintain the temperature of the mixture at 65-75℃, add boric acid, stir for 2-3 h, raise the temperature to 80-85℃, and continue stirring for 3-4 h to obtain boron-doped silane; wherein the mass ratio of ethanol, hydrochloric acid aqueous solution, vinyltrimethoxysilane, and boric acid is (8.6-17.2):(19.9-39.8):(0.7-1.4):(0.9-1.8); Step B2: Cut the hemp stems that have been peeled of their bast layers into 1-4cm pieces, crush them, soak them in deionized water for 10-15 hours, then stir them in a 1mol / L sodium hydroxide aqueous solution at 70-80℃ for 2-4 hours, and finally stir them in a 2wt% sodium hypochlorite aqueous solution at 60-70℃ for 2-4 hours. Filter, wash, freeze dry to obtain hemp fiber. A 0.1 wt% chitosan / acetic acid solution was mixed with a 1 wt% boron-doped silane aqueous solution, hemp fiber was added, the mixture was ultrasonically treated, and then freeze-dried at -80 to -75 °C and ground to obtain aerogel powder; wherein the mass ratio of chitosan acetic acid solution, boron-doped silane aqueous solution and hemp fiber was 100:(2-6):(0.003-0.005); Step B3: Add para-ester and 4-mercaptobenzaldehyde to dimethyl sulfoxide, sonicate at 40-45℃ for 40-60 min, then raise the temperature to 60-70℃ and react for 3-4 h. Add DOPO, raise the temperature to 80-90℃ and continue the reaction for 4-5 h. Cool to room temperature, centrifuge, wash, and dry to obtain the flame retardant modifier. The mass ratio of para-ester, 4-mercaptobenzaldehyde, dimethyl sulfoxide, and DOPO is (14-28):(6.9-13.8):(500-600):(10.8-21.6). Aerogel powder was added to N,N-dimethylformamide and ultrasonically dispersed for 20-40 min. The mixture was then heated to 50-80℃, followed by the addition of flame retardant modifier and azobisisobutyronitrile. The mixture was stirred and reacted for 3-5 h. After the reaction was completed, the mixture was centrifuged, washed, and dried to obtain the modified aerogel. The mass ratio of aerogel powder, N,N-dimethylformamide, flame retardant modifier, and azobisisobutyronitrile was (3-5):(120-150):(1-1.5):(0.2-0.3).

10. A flame-retardant and heat-insulating layered composite fabric prepared by the preparation method of the flame-retardant and heat-insulating layered composite fabric as described in any one of claims 1-9.

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