A multi-layer composite flame-retardant fabric and a preparation method thereof

Abstract

The application provides a multilayer composite flame-retardant fabric, which is composed of a base cloth layer, a flame-retardant electrostatic spinning layer and a coating layer, the flame-retardant electrostatic spinning layer is composed of Mg(OH)2 and aramid fiber, and the coating layer is an organic modified sheet-shaped alumina layer, and a preparation method thereof, which comprises the following steps: adding the organic modified sheet-shaped alumina into an aqueous polyurethane to obtain a polyurethane coating solution; hot-pressing the flame-retardant electrostatic spinning layer on the surface of the base cloth layer, then coating the polyurethane coating solution on the flame-retardant electrostatic spinning layer, and drying to obtain the organic modified sheet-shaped alumina layer, so that the multilayer composite flame-retardant fabric is prepared. In the application, the ordinary base cloth layer is combined with aramid electrostatic spinning, and the aramid electrostatic spinning film and the ordinary base cloth are combined, so that the flame-retardant effect can be achieved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of functional fabric, in particular to a multi-layer composite flame-retardant fabric and a preparation method thereof. BACKGROUND

[0002] At present, there are generally three methods for processing flame-retardant fabric: (1) using flame-retardant fibers to weave high-performance flame-retardant fabric; (2) flame-retardant finishing of fabric to obtain excellent flame-retardant performance; (3) blending flame-retardant fibers with common fibers and performing flame-retardant finishing on the finished product, so that the fabric has good hand feeling and excellent flame-retardant performance.

[0003] Flame-retardant finishing mainly performs surface treatment on the fibers in the fabric in the finishing process of the textile through adsorption deposition and chemical bonding, so that the flame retardant is fixed on the fabric, thereby obtaining the flame-retardant effect of the fabric. The processing forms of flame-retardant finishing of fabric mainly include the following:

[0004] 1) Immersion drying method: process flow: immersion → drying → post-treatment; it is to immerse the fabric in the flame-retardant liquid for a certain time, and then take it out and dry it. Sometimes, the flame-retardant finishing can be carried out in the same bath as the dyeing process. The padding liquid is a flame-retardant solution, which is suitable for flame-retardant finishing of cellulose fiber fabric.

[0005] 2) Pad-bake method: this method is the most commonly used method for flame-retardant finishing, and the process flow is: padding → pre-drying → baking → post-treatment.

[0006] 3) Coating method: it is to mix the flame retardant into the resin for processing. According to different mechanical equipment, it is divided into doctor blade coating method, casting coating method and calender coating method. Different products adopt different processing methods.

[0007] 4) Spray method: thick curtains, large carpets and other commodities that cannot be processed by ordinary equipment can be subjected to manual spray flame-retardant finishing in the last process. For fabrics with patterned, tufted and raised surfaces, if the immersion method is used, the surface pile pattern will be damaged, so the continuous spray method is generally adopted.

[0008] 5) Organic solvent method: the flame retardant is dissolved in an organic solvent, and then subjected to flame-retardant finishing. It can shorten the finishing time. In the operation process, attention must be paid to the toxicity and flammability of the solvent. Compared with the modification of raw yarn, the flame-retardant finishing process is simple, the investment is small, the effect is quick, and it is suitable for the development of new products. However, it will have a certain influence on the strength, hand feeling and color of the fabric, and the flame-retardant durability is not as good as that of the raw yarn modification.

[0009] Aramid fiber is a high-performance fiber with excellent flame-retardant performance, high strength and modulus. At present, it is mixed with other fibers to improve the application range of fabrics in terms of performance. In order to reduce the cost of pure aramid flame-retardant fabric, better utilize durable flame-retardant fiber, and further improve the flame-retardant performance of the fabric, an optimized process is used to manufacture high flame-retardant performance textiles that meet different functional needs. SUMMARY

[0010] The technical problem to be solved is to provide a multi-layer composite flame-retardant fabric which uses ordinary base cloth layer combined with aramid electrospinning layer to improve the flame-retardant performance of the fabric by composite flame-retardant method.

[0011] Technical scheme: A multi-layer composite flame-retardant fabric is composed of a base cloth layer, a flame-retardant electrospinning layer and a coating layer. The flame-retardant electrospinning layer is composed of Mg(OH)2 and aramid. The coating layer is an organic modified sheet-shaped aluminum oxide layer.

[0012] Preferably, the preparation method of the flame-retardant electrospinning layer comprises the following steps:

[0013] S1. LiCl is added to N,N-dimethylacetamide, stirred until completely dissolved, then stirred uniformly, and then meta-aramid pulp is added and stirred until completely dissolved to obtain aramid spinning solution;

[0014] S2. Gelatin / magnesium salt composite microcapsules are added to ice water and stirred uniformly to obtain a composite microcapsule aqueous solution;

[0015] S3. The aramid spinning solution prepared in step S1 is used as the skin layer, and the composite microcapsule aqueous solution prepared in step S2 is used as the core layer, and coaxial electrospinning is performed to obtain aramid electrospinning film;

[0016] S4. The aramid electrospinning film prepared in step S3 is immersed in heated NaOH solution and ultrasonic oscillation is performed to obtain flame-retardant electrospinning film.

[0017] Preferably, the concentration of LiCl in N,N-dimethylacetamide is 2-4%, the concentration of the aramid spinning solution is 8-12%, and the concentration of the composite microcapsule aqueous solution is 5-10wt%.

[0018] Preferably, the flow rate ratio of the skin layer to the core layer in step S3 is 0.2-0.4:0.8-1.2.

[0019] Preferably, the preparation of the gelatin / salt composite microcapsules comprises the following steps:

[0020] S11. Magnesium chloride and aluminum chloride are added to an aqueous solution to prepare a saturated salt aqueous solution;

[0021] S12. Swelling the gelatin in water and heating to dissolve, to prepare a gelatin solution with a concentration of 6-9wt%;

[0022] S13. Using the saturated salt water solution prepared in step S11 as the core material, and the gelatin solution prepared in step 12 as the wall material, mixing the wall material and the core material according to a mass ratio of 10-15:1, stirring uniformly, and then performing spray drying to obtain the composite microcapsule.

[0023] Preferably, the inlet air temperature of the spray drying is 150-160℃, and the feed flow rate is 2.5-3.5mL / min.

[0024] Preferably, the preparation method of the modified sheet-shaped aluminum oxide is as follows:

[0025] S1-1. Adding sheet-shaped aluminum oxide to an aqueous solution of polyethylene diamine, the mass ratio of sheet-shaped aluminum oxide to polyethylene diamine being 1:5-10, ultrasonic stirring reaction, filtering and drying to obtain polyethylene diamine-aluminum oxide sheet-shaped powder;

[0026] S1-2. Adding the polyethylene diamine-aluminum oxide sheet-shaped powder to water, ultrasonic stirring until mixed uniformly, then adding a phytic acid solution with a concentration of 10-20wt%, heating and stirring at 50-60℃ for 2h, centrifuging and filtering after cooling to room temperature to obtain modified sheet-shaped aluminum oxide.

[0027] The preparation method of the multi-layer composite flame-retardant fabric described above comprises the following steps:

[0028] Adding the organically modified sheet-shaped aluminum oxide to the aqueous polyurethane to obtain a polyurethane coating liquid;

[0029] Hot-pressing the flame-retardant electrospun layer on the surface of the base fabric layer, then coating the polyurethane coating liquid on the flame-retardant electrospun layer, and drying to obtain the organically modified sheet-shaped aluminum oxide layer, i.e. to prepare the multi-layer composite flame-retardant fabric.

[0030] Beneficial effects: The flame-retardant fabric of the present application has the following advantages:

[0031] 1. In the present application, ordinary base fabric layer is compounded with aramid electrospun film to achieve the effect of flame retardation.

[0032] 2. In the present application, ordinary aramid electrospun film has a flame-retardant effect, but the flame-retardant effect is limited, so the coaxial electrospinning method is used to prepare a composite electrospun film in the present application, the skin layer is aramid, and the core layer is a salt-containing microcapsule aqueous solution. 2+ , reacts with the base, and a part of Mg 2+will diffuse to the surface of the fiber with the molecular motion, and react with OH - Mg(OH)2 is generated, most of which remains in the core layer, and Mg(OH)2 is generated in the core layer, obtaining an electrospun membrane material coated with inorganic flame retardant inside and outside, which improves the flame retardant effect of aramid fiber;

[0033] 3. In addition to using electrospun membrane composite to improve the flame retardant effect in the present application, in order to obtain better flame retardant effect and fabric appearance, a coating layer is coated on the outside of the electrospun membrane material, and flaky aluminum oxide is used in the coating layer. The flaky aluminum oxide coated on the surface of the fabric has good sheet layer isolation performance, and N and P are cut off on the surface of the aluminum oxide, obtaining a composite flame retardant containing N and P, which further improves the flame retardant effect. DETAILED DESCRIPTION

[0034] The present application will be further described below in conjunction with examples, and the following examples are an explanation of the present application, and the present application is not limited to the following examples:

[0035] Example 1

[0036] The preparation method of the flame-retardant electrospun layer comprises the following steps:

[0037] S1. Add LiCl to N,N-dimethylacetamide, the concentration of LiCl in N,N-dimethylacetamide is 2%, after stirring to completely dissolve, stirring uniformly, add meta-aramid pulp, stirring to completely dissolve, obtain aramid spinning solution with concentration of 8%;

[0038] S2. Add gelatin / magnesium salt composite microcapsules to ice water, mix and stir uniformly, obtain composite microcapsule aqueous solution with concentration of 10wt%;

[0039] S3. Use the aramid spinning solution prepared in step S1 as the skin layer, and use the composite microcapsule aqueous solution prepared in step S2 as the core layer, perform coaxial electrospinning, the flow rate ratio of the skin layer and the core layer is 0.2mL / h:0.8mL / h, obtain aramid electrospun membrane;

[0040] S4. Dip the aramid electrospun membrane prepared in step S3 in heated NaOH solution, ultrasonic oscillation reaction, obtain flame-retardant electrospun membrane;

[0041] The preparation of the gelatin / salt composite microcapsule comprises the following steps:

[0042] S11. Add magnesium chloride and aluminum chloride to an aqueous solution to prepare a saturated salt aqueous solution;

[0043] S12. Swell the gelatin in water, heat to dissolve, prepare gelatin solution with concentration of 6wt%;

[0044] S13. The saturated salt water solution prepared in step S11 is used as the core material, and the gelatin solution prepared in step 12 is used as the wall material. The wall material and the core material are mixed in a mass ratio of 15:1, stirred uniformly, and then subjected to spray drying. The inlet air temperature of the spray drying is 150℃, and the feeding flow rate is 2.5mL / min. The composite microcapsules are obtained.

[0045] Example 2

[0046] The preparation method of the flame-retardant electrospun layer comprises the following steps:

[0047] S1. LiCl is added to N,N-dimethylacetamide, and the concentration of LiCl in N,N-dimethylacetamide is 4%. After stirring until completely dissolved, the mixture is stirred uniformly, and then meta-aramid pulp is added. After stirring until completely dissolved, the aramid spinning solution with a concentration of 12% is obtained;

[0048] S2. The gelatin / magnesium salt composite microcapsules are added to ice water, and stirred uniformly to obtain a composite microcapsule aqueous solution with a concentration of 5wt%;

[0049] S3. The aramid spinning solution prepared in step S1 is used as the skin layer, and the composite microcapsule aqueous solution prepared in step S2 is used as the core layer. Coaxial electrospinning is performed, and the flow rate ratio of the skin layer to the core layer is 0.4mL / h:1.2mL / h. The aramid electrospun film is obtained;

[0050] S4. The aramid electrospun film prepared in step S3 is immersed in a heated NaOH solution and subjected to ultrasonic oscillation reaction to obtain the flame-retardant electrospun film;

[0051] The preparation of the gelatin / salt composite microcapsules comprises the following steps:

[0052] S11. Magnesium chloride and aluminum chloride are added to an aqueous solution to prepare a saturated salt water solution;

[0053] S12. Gelatin is added to water, swelled, and then dissolved by heating to prepare a gelatin solution with a concentration of 9wt%;

[0054] S13. The saturated salt water solution prepared in step S11 is used as the core material, and the gelatin solution prepared in step 12 is used as the wall material. The wall material and the core material are mixed in a mass ratio of 10:1, stirred uniformly, and then subjected to spray drying. The inlet air temperature of the spray drying is 160℃, and the feeding flow rate is 3.5mL / min. The composite microcapsules are obtained.

[0055] Example 3

[0056] The preparation method of the flame-retardant electrospun layer comprises the following steps:

[0057] S1. LiCl was added to N,N-dimethylacetamide, the concentration of LiCl in N,N-dimethylacetamide was 3%, after stirring to completely dissolve, stirring uniformly, meta-aramid pulp was added, stirring to completely dissolve, to obtain aramid spinning solution with a concentration of 10%;

[0058] S2. The gelatin / magnesium salt composite microcapsules were added to ice water, mixed and stirred uniformly to obtain a composite microcapsule aqueous solution with a concentration of 8wt%;

[0059] S3. The aramid spinning solution prepared in step S1 was used as the skin layer, and the composite microcapsule aqueous solution prepared in step S2 was used as the core layer, and coaxial electrospinning was performed, the flow rate ratio of the skin layer to the core layer was 0.3mL / h:1mL / h, to obtain an aramid electrospun membrane;

[0060] S4. The aramid electrospun membrane prepared in step S3 was immersed in a heated NaOH solution and ultrasonically oscillated to obtain a flame-retardant electrospun membrane;

[0061] The preparation of the gelatin / salt composite microcapsules comprises the following steps:

[0062] S11. Magnesium chloride and aluminum chloride were added to an aqueous solution to prepare a saturated salt aqueous solution;

[0063] S12. Gelatin was added to water, swelled, heated and dissolved to prepare a gelatin solution with a concentration of 8wt%;

[0064] S13. The saturated salt aqueous solution prepared in step S11 was used as the core material, and the gelatin solution prepared in step 12 was used as the wall material, the wall material and the core material were mixed according to a mass ratio of 12:1, stirred uniformly, and then spray dried, the inlet air temperature of the spray drying was 155℃, and the feed flow rate was 3mL / min, to obtain composite microcapsules.

[0065] Flame-retardant performance test of the electrospun membranes in Examples 1-3 (GB / T 5455-1997)

[0066] Afterglow time / s Afterflame time / s Example 1 1.5 1.1 Example 2 1.4 0.9 Example 3 1.4 0.9 Common aramid electrospun membrane 2.3 1.5

[0067] Example 4

[0068] The preparation method of the multi-layer composite flame-retardant fabric comprises the following steps:

[0069] Organic modified sheet-like aluminum oxide was added to the aqueous polyurethane to obtain a polyurethane coating liquid with a concentration of 4wt%;

[0070] The flame-retardant electrospun layer prepared in Example 3 was hot-pressed and combined on the surface of the base fabric layer, and then the polyurethane coating liquid was coated on the flame-retardant electrospun layer, the amount of the coating liquid was 10g / m 2, and the organic modified sheet-like alumina layer is obtained, that is, the multilayer composite flame-retardant fabric is prepared.

[0071] The preparation method of the modified sheet-like alumina is as follows:

[0072] S1-1. The sheet-like alumina is added into a water solution of polyethylene diamine, the mass ratio of the sheet-like alumina and the polyethylene diamine is 1:5, and ultrasonic stirring reaction is performed, and polyethylene diamine-alumina sheet-like powder is obtained by filtration and drying.

[0073] S1-2. The polyethylene diamine-alumina sheet-like powder is added into water, and ultrasonic stirring is performed until the mixture is uniform, then a 10wt% phytic acid solution is added, heating and stirring are performed at 50°C for 2h, centrifugal filtration is performed after cooling to room temperature, and the modified sheet-like alumina is obtained.

[0074] Example 5

[0075] The preparation method of the multilayer composite flame-retardant fabric comprises the following steps:

[0076] The organic modified sheet-like alumina is added into the water-based polyurethane to obtain a polyurethane coating liquid with a concentration of 8wt%;

[0077] The flame-retardant electrospun layer prepared in Example 3 is hot-pressed and combined on the surface of the base fabric layer, then the polyurethane coating liquid is coated on the flame-retardant electrospun layer, and the amount of the coating liquid is 20g / m 2 , and the organic modified sheet-like alumina layer is obtained, that is, the multilayer composite flame-retardant fabric is prepared.

[0078] The preparation method of the modified sheet-like alumina is as follows:

[0079] S1-1. The sheet-like alumina is added into a water solution of polyethylene diamine, the mass ratio of the sheet-like alumina and the polyethylene diamine is 1:10, and ultrasonic stirring reaction is performed, and polyethylene diamine-alumina sheet-like powder is obtained by filtration and drying.

[0080] S1-2. The polyethylene diamine-alumina sheet-like powder is added into water, and ultrasonic stirring is performed until the mixture is uniform, then a 20wt% phytic acid solution is added, heating and stirring are performed at 60°C for 2h, centrifugal filtration is performed after cooling to room temperature, and the modified sheet-like alumina is obtained.

[0081] Example 6

[0082] The preparation method of the multilayer composite flame-retardant fabric comprises the following steps:

[0083] The organic modified sheet-like alumina is added into the water-based polyurethane to obtain a polyurethane coating liquid with a concentration of 5wt%;

[0084] The flame-retardant electrospinning layer prepared in Example 3 is hot-pressed on the surface of the base fabric layer, and then a polyurethane coating solution is coated on the flame-retardant electrospinning layer, and the amount of the coating solution is 14 g / m 2 , and an organic modified sheet-like alumina layer is obtained by drying, thereby preparing a multilayer composite flame-retardant fabric.

[0085] The preparation method of the modified sheet-like alumina is as follows:

[0086] S1-1. Sheet-like alumina is added to a polyethylene diamine aqueous solution, and the mass ratio of the sheet-like alumina to the polyethylene diamine is 1:8, and ultrasonic stirring is performed for reaction, and polyethylene diamine-alumina sheet-like powder is obtained by filtration and drying.

[0087] S1-2. The polyethylene diamine-alumina sheet-like powder is added to water, and ultrasonic stirring is performed until the mixture is uniform, and then a phytic acid solution with a concentration of 13 wt% is added, and stirring is performed at 58°C for 2 h, and after the solution is cooled to room temperature, centrifugal filtration is performed, and modified sheet-like alumina is obtained.

[0088] Example 7

[0089] The preparation method of the multilayer composite flame-retardant fabric comprises the following steps:

[0090] The organic modified sheet-like alumina is added to the aqueous polyurethane to obtain a polyurethane coating solution with a concentration of 7 wt%;

[0091] The flame-retardant electrospinning layer prepared in Example 3 is hot-pressed on the surface of the base fabric layer, and then a polyurethane coating solution is coated on the flame-retardant electrospinning layer, and the amount of the coating solution is 16 g / m 2 , and an organic modified sheet-like alumina layer is obtained by drying, thereby preparing a multilayer composite flame-retardant fabric.

[0092] The preparation method of the modified sheet-like alumina is as follows:

[0093] S1-1. Sheet-like alumina is added to a polyethylene diamine aqueous solution, and the mass ratio of the sheet-like alumina to the polyethylene diamine is 1:6, and ultrasonic stirring is performed for reaction, and polyethylene diamine-alumina sheet-like powder is obtained by filtration and drying.

[0094] S1-2. The polyethylene diamine-alumina sheet-like powder is added to water, and ultrasonic stirring is performed until the mixture is uniform, and then a phytic acid solution with a concentration of 18 wt% is added, and stirring is performed at 55°C for 2 h, and after the solution is cooled to room temperature, centrifugal filtration is performed, and modified sheet-like alumina is obtained.

[0095] Comparative Example 1

[0096] The preparation method of the multilayer composite flame-retardant fabric comprises the following steps:

[0097] The modified spherical alumina is added into the aqueous polyurethane to obtain a polyurethane coating liquid with a concentration of 7wt%;

[0098] The flame-retardant electrospun layer prepared in Example 3 is hot-pressed on the surface of the base fabric layer, and then a polyurethane coating liquid is coated on the flame-retardant electrospun layer, the amount of the coating liquid being 16g / m 2 , and an organic modified alumina layer is obtained by drying, thereby preparing a multilayer composite flame-retardant fabric.

[0099] The preparation method of the modified spherical alumina is as follows:

[0100] S1-1. Alumina is added into an aqueous solution of polyethylene diamine, the mass ratio of the flaky alumina to the polyethylene diamine being 1:6, and an ultrasonic stirring reaction is performed, and a polyethylene diamine-alumina powder is obtained by filtration and drying.

[0101] S1-2. The polyethylene diamine-alumina powder is added into water, and ultrasonic stirring is performed until the mixture is uniform, and then a phytic acid solution with a concentration of 18wt% is added, and stirring is performed at 55℃ for 2h, and after the mixture is cooled to room temperature, centrifugal filtration is performed, and modified alumina is obtained.

[0102] Comparative Example 2

[0103] The preparation method of the multilayer composite flame-retardant fabric comprises the following steps:

[0104] The modified spherical alumina is added into the aqueous polyurethane to obtain a polyurethane coating liquid with a concentration of 7wt%;

[0105] The aramid electrospun layer is hot-pressed on the surface of the base fabric layer, and then a polyurethane coating liquid is coated on the aramid electrospun layer, the amount of the coating liquid being 16g / m 2 , and an organic modified alumina layer is obtained by drying, thereby preparing a multilayer composite flame-retardant fabric.

[0106] The preparation method of the modified spherical alumina is as follows:

[0107] S1-1. Alumina is added into an aqueous solution of polyethylene diamine, the mass ratio of the flaky alumina to the polyethylene diamine being 1:6, and an ultrasonic stirring reaction is performed, and a polyethylene diamine-alumina powder is obtained by filtration and drying.

[0108] S1-2. The polyethylene diamine-alumina powder is added into water, and ultrasonic stirring is performed until the mixture is uniform, and then a phytic acid solution with a concentration of 18wt% is added, and stirring is performed at 55℃ for 2h, and after the mixture is cooled to room temperature, centrifugal filtration is performed, and modified alumina is obtained.

[0109] Comparative Example 3

[0110] The preparation method of the multilayer composite flame-retardant fabric comprises the following steps:

[0111] The organic modified sheet-shaped aluminum oxide is added into the aqueous polyurethane to obtain a polyurethane coating liquid with a concentration of 5wt%;

[0112] The flame-retardant electrospun layer is hot-pressed on the surface of the base fabric layer, and then a polyurethane coating liquid is coated on the flame-retardant electrospun layer, and the amount of the coating liquid is 14g / m 2 , and a organic modified sheet-shaped aluminum oxide layer is obtained by drying, that is, a multilayer composite flame-retardant fabric is prepared;The preparation method of the modified sheet-shaped aluminum oxide is:

[0113] S1-1. The sheet-shaped aluminum oxide is added into the aqueous solution of polyethylene diamine, and the mass ratio of the sheet-shaped aluminum oxide to the polyethylene diamine is 1:8, and the ultrasonic stirring reaction is carried out, and the polyethylene diamine-aluminum oxide sheet-shaped powder is obtained by filtering and drying;

[0114] S1-2. The polyethylene diamine-aluminum oxide sheet-shaped powder is added into water, and ultrasonic stirring is carried out until the mixture is uniform, and then a phytic acid solution with a concentration of 13wt% is added, and stirring is carried out at 58℃ for 2h, and after the solution is cooled to room temperature, centrifugal filtration is carried out, and the modified sheet-shaped aluminum oxide is obtained;

[0115] The preparation method of the flame-retardant electrospun layer comprises the following steps:

[0116] S1. LiCl is added into N,N-dimethylacetamide, and the concentration of LiCl in N,N-dimethylacetamide is 3%, and after stirring until completely dissolved, the mixture is stirred uniformly, and then meta-aramid pulp is added, and stirring is carried out until completely dissolved, and a aramid spinning liquid with a concentration of 10% is obtained;

[0117] S2. Nano-Mg(OH)2 is added into water, and ultrasonic dispersion is carried out to obtain a Mg(OH)2 suspension solution with a concentration of 8.8wt%;

[0118] S3. The aramid spinning liquid prepared in step S1 is used as a skin layer, and the Mg(OH)2 suspension solution prepared in step S2 is used as a core layer, and coaxial electrospinning is carried out, and the flow rate ratio of the skin layer to the core layer is 0.3mL / h:1.2mL / h, and an aramid electrospun film is obtained.

[0119] Comparative Example 4

[0120] The preparation method of the multilayer composite flame-retardant fabric comprises the following steps:

[0121] The organic modified sheet-shaped aluminum oxide is added into the aqueous polyurethane to obtain a polyurethane coating liquid with a concentration of 5wt%;

[0122] The flame-retardant electrospun layer is hot-pressed on the surface of the base fabric layer, and then a polyurethane coating liquid is coated on the flame-retardant electrospun layer, and the amount of the coating liquid is 14g / m 2, and the organic modified sheet-like alumina layer is obtained, that is, a multilayer composite flame-retardant fabric is prepared; wherein the preparation method of the modified sheet-like alumina is as follows:

[0123] S1-1. Sheet-like alumina is added into an aqueous solution of polyethylene diamine, the mass ratio of the sheet-like alumina and the polyethylene diamine is 1:8, ultrasonic stirring is performed for reaction, and polyethylene diamine-alumina sheet-like powder is obtained by filtration and drying;

[0124] S1-2. The polyethylene diamine-alumina sheet-like powder is added into water, ultrasonic stirring is performed until the mixture is uniform, then a phytic acid solution with a concentration of 13wt% is added, heating and stirring are performed at 58°C for 2h, centrifugal filtration is performed after the solution is cooled to room temperature, and the modified sheet-like alumina is obtained;

[0125] The preparation method of the flame-retardant electrospun layer comprises the following steps:

[0126] S1. LiCl is added into N,N-dimethylacetamide, the concentration of the LiCl in the N,N-dimethylacetamide is 4%, after stirring until the LiCl is completely dissolved, the mixture is stirred until it is uniform, then meta-aramid pulp is added, stirring is performed until the meta-aramid pulp is completely dissolved, and an aramid spinning solution with a concentration of 12% is obtained;

[0127] S2. MgCl2 is added into water, and the mixture is stirred until it is uniform, so that a saturated concentration MgCl2 aqueous solution is obtained;

[0128] S3. The aramid spinning solution prepared in step S1 is used as a skin layer, and the saturated concentration MgCl2 aqueous solution prepared in step S2 is used as a core layer, coaxial electrospinning is performed, and the flow rate ratio of the skin layer and the core layer is 0.4mL / h:1.5mL / h, so that an aramid electrospun film is obtained; and S4. The aramid electrospun film prepared in step S3 is immersed in a heated NaOH solution, ultrasonic oscillation reaction is performed, and a flame-retardant electrospun film is obtained.

[0129] The combustion performance test is performed according to GB / T 5455-1997 Textiles-Test Methods for Flammability of Vertical Burning of Textiles, and the test results are as follows:

[0130] Afterflame time / s Afterglow time / s Damage length / mm Example 4 1.3 0.9 39 Example 5 1.2 0.9 37 Example 6 1.2 0.8 35 Example 7 1.1 0.7 33 Comparative Example 1 1.6 1.3 44 Comparative Example 2 1.8 1.5 46 Comparative Example 3 2.1 1.6 48 Comparative Example 4 2.3 1.8 49

[0131] The base fabric layer in the above examples and comparative examples all uses a polyester fabric with a grammage of 230g / m 2 .

[0132] Obviously, the above examples are merely examples for clearly illustrating the present application, and are not intended to limit the embodiments. Based on the above description, other different forms of changes or variations can be made by those skilled in the art. Here, all the embodiments cannot be enumerated, and the changes or variations derived therefrom are still within the protection scope of the present application.

Claims

1. A multi-layer composite flame resistant fabric, characterized in that: The flame-retardant fabric is composed of a base cloth layer, a flame-retardant electrostatic spinning layer and a coating layer, the flame-retardant electrostatic spinning layer is composed of Mg(OH)2 and aramid, and the coating layer is an organic modified sheet-shaped alumina layer. The preparation method of the flame-retardant electrostatic spinning layer comprises the following steps: S1. LiCl is added to N,N-dimethylacetamide, stirred until completely dissolved, then stirred uniformly, and then meta-aramid pulp is added and stirred until completely dissolved to obtain aramid spinning solution; S2. Gelatin / magnesium salt composite microcapsules are added to ice water, mixed and stirred uniformly to obtain a composite microcapsule aqueous solution; S3. The aramid spinning solution prepared in step S1 is used as a skin layer, and the composite microcapsule aqueous solution prepared in step S2 is used as a core layer, and coaxial electrostatic spinning is performed to obtain an aramid electrostatic spinning film; S4. The aramid electrostatic spinning film prepared in step S3 is immersed in a heated NaOH solution and subjected to ultrasonic oscillation reaction to obtain a flame-retardant electrostatic spinning film; The preparation of the gelatin / salt composite microcapsules in step S2 comprises the following steps: S11. Magnesium chloride and aluminum chloride are added to an aqueous solution to prepare a saturated salt aqueous solution; S12. Gelatin is added to water, swelled and then dissolved by heating to prepare a gelatin solution with a concentration of 6-9 wt%; S13. The saturated salt aqueous solution prepared in step S11 is used as a core material, and the gelatin solution prepared in step 12 is used as a wall material, the wall material and the core material are mixed in a mass ratio of 10-15:1, stirred uniformly and then subjected to spray drying to obtain composite microcapsules.

2. The multi-layer composite flame resistant fabric of claim 1, wherein: The concentration of LiCl in N,N-dimethylacetamide is 2-4%, the concentration of the aramid spinning solution is 8-12%, and the concentration of the composite microcapsule aqueous solution is 5-10 wt%.

3. The multi-layer composite flame resistant fabric of claim 1, wherein: The flow rate ratio of the skin layer to the core layer in step S3 is 0.2-0.4:0.8-1.

2.

4. The multi-layer composite flame resistant fabric of claim 1, wherein: The inlet air temperature of the spray drying is 150-160℃, and the feed flow rate is 2.5-3.5 mL / min.

5. The multi-layer composite flame resistant fabric of claim 1, wherein, The preparation method of the modified sheet-shaped alumina comprises the following steps: S1-1. Sheet-shaped alumina is added to an aqueous solution of polyethylene diamine, the mass ratio of the sheet-shaped alumina to the polyethylene diamine is 1:5-10, and ultrasonic stirring is performed, followed by filtration and drying to obtain polyethylene diamine-alumina sheet-shaped powder; S1-2. The polyethylene diamine-alumina sheet-shaped powder is added to water, ultrasonic stirring is performed until mixed uniformly, then a phytic acid solution with a concentration of 10-20 wt% is added, heating and stirring are performed at 50-60℃ for 2 h, centrifugal filtration is performed after the solution is cooled to room temperature, and modified sheet-shaped alumina is obtained.

6. The method of making a multi-layer composite flame resistant fabric of claim 1, wherein, The preparation method comprises the following steps: The organic modified sheet-shaped alumina is added to the aqueous polyurethane to obtain a polyurethane coating solution; The flame-retardant electrostatic spinning layer is hot-pressed and combined on the surface of the base cloth layer, then the polyurethane coating solution is coated on the flame-retardant electrostatic spinning layer, and drying is performed to obtain the organic modified sheet-shaped alumina layer, i.e. a multilayer composite flame-retardant fabric is prepared.