Zr-mof-based persistent flame-retardant and smoke-suppressing wool fabric and preparation method thereof

Abstract

The application relates to a Zr-MOF-based persistent flame-retardant and smoke-suppressing wool fabric and a preparation method thereof, and belongs to the technical field of textiles. The preparation method comprises the following steps: S1, dipping the wool fabric in a pretreatment liquid to perform two-dipping and two-rolling treatment, and then performing pre-drying and baking treatment to obtain pretreated wool fabric; S2, dipping the pretreated wool fabric in a zirconium salt solution to perform modification treatment, and obtaining modified wool fabric; S3, dipping the modified wool fabric in a trimesic acid solution and a treatment liquid in sequence to perform treatment, and obtaining flame-retardant and smoke-suppressing wool fabric; and S4, repeating S2-S3 to obtain the Zr-MOF-based persistent flame-retardant and smoke-suppressing wool fabric. First, the wool fabric is pretreated by using citric acid, then the wool fabric is modified by using a zirconium salt, and finally the wool fabric is treated by using trimesic acid and 2,4,6-trichloropyrimidine solution in sequence, Zr-MOF nanomaterials are constructed on the wool fabric, and the persistent flame-retardant and smoke-suppressing wool fabric is prepared.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of textiles, and particularly relates to a Zr-MOF-based durable flame-retardant and smoke-suppressing wool fabric and a preparation method thereof. BACKGROUND

[0002] Wool fibers have excellent properties such as good warmth retention, high elasticity, softness, and skin-friendliness. As a high-end natural fiber material, wool is widely used in the fields of clothing, blankets, and curtains. However, wool fibers are flammable materials that cannot self-extinguish after ignition and release toxic gases such as hydrogen cyanide and sulfur dioxide, which seriously endanger people's life and property safety. It is of great significance to improve the flame-retardant and smoke-suppressing performance of wool fabrics. With the increasing demand for ecological and environmental protection, the use of most halogen flame retardants has been banned. Phosphorus-based flame retardants have become the largest category of halogen-free products. However, recent studies have shown that organic phosphorus flame retardants have neurotoxicity and reproductive toxicity, and are prone to water pollution and other defects. At present, there are great challenges in developing halogen-free and phosphorus-free flame-retardant systems for the flame-retardant and smoke-suppressing modification of wool fabrics.

[0003] Metal-organic framework (MOF) is a kind of porous organic-inorganic hybrid material formed by the combination of metal clusters and organic ligands. The metal part of MOF has a catalytic effect, which can promote the carbonization of high molecular materials, and the organic ligand part can generate high-stability aromatic residual carbon to inhibit combustion, thereby improving the flame-retardant performance of the material. However, currently, MOF materials are mainly used for the addition of flame-retardant modification of high molecular composite materials, and there are few studies on the flame-retardant modification of textiles. Reference (Sun A, Zhu J, Wang W, et al. Preparation and properties of iron phytate MOF modified flame-retardant polyester [J]. Journal of Beijing Institute of Clothing Technology (Natural Science Edition), 2023, 43(2): 1-10.) uses bio-based phytic acid as a ligand and iron nitrate as a metal ion donor to prepare a metal-organic framework material flame retardant (Fe-PMOF), and a composite flame-retardant polyester (Fe-PMOF-PET) is prepared by melt blending. The invention patent CN 117005199 A discloses the preparation of MOFs modified nitrogen-phosphorus-silicon flame retardant and its application in cotton fabric. The nitrogen-phosphorus-silicon flame retardant is synthesized by using tris(2-hydroxyethyl) isocyanurate, maleic anhydride, and tetrahydroxymethyl phosphorus sulfate, and combined with MOFs material for the finishing of cotton fabric. MOFs plays a synergistic flame-retardant effect, but MOFs alone cannot achieve flame-retardant effect on cotton fabric.

[0004] How to improve the durability of MOF materials on wool fabric is also a problem worth paying attention to. Invention patent CN114875674A discloses a preparation method of antibacterial wool fabric loaded with PVP / Cu-MOFs. In order to improve the loading of Cu-MOFs and ZnO on wool fabric, PVP is used as a coating agent to fix Cu-MOFs on wool fabric, thereby improving the antibacterial performance of wool fabric. However, the flame retardant efficiency of this system is poor, and PVP is a flammable polymer material, so the flame retardant performance of the modified wool fabric is poor.

[0005] Therefore, how to develop more efficient MOF flame retardant materials and use them for durable flame retardant and smoke suppression modification of wool fabric is a great challenge. SUMMARY

[0006] To solve the above technical problems, the present application provides a Zr-MOF-based persistent flame-retardant and smoke-suppression wool fabric and a preparation method thereof. First, the wool fabric is pretreated with citric acid, then modified with zirconium salt, and finally treated with trimesic acid and 2,4,6-trichloropyrimidine solution in sequence to construct Zr-MOF nanomaterials on the wool fabric, thereby obtaining the persistent flame-retardant and smoke-suppression wool fabric.

[0007] The first object of the present application is to provide a preparation method of a Zr-MOF-based persistent flame-retardant and smoke-suppression wool fabric, comprising the following steps:

[0008] S1, dip the wool fabric in a pretreatment liquid for double-dip double-nip treatment, then perform pre-drying and baking treatment to obtain a pretreated wool fabric; the pretreatment liquid comprises citric acid, sodium hypophosphite and water;

[0009] S2, dip the pretreated wool fabric of S1 in a zirconium salt solution for modification treatment to obtain a modified wool fabric;

[0010] S3, dip the modified wool fabric of S2 in trimesic acid solution and treatment liquid in sequence for treatment to obtain a flame-retardant and smoke-suppression wool fabric; the treatment liquid comprises 2,4,6-trichloropyrimidine, sodium bicarbonate and water;

[0011] S4, repeat S2-S3 to obtain the Zr-MOF-based persistent flame-retardant and smoke-suppression wool fabric.

[0012] In an embodiment of the present application, in S1, the concentration of citric acid in the pretreatment liquid is 30g / L-50g / L, and the concentration of sodium hypophosphite is 15g / L-30g / L. Citric acid contains three carboxyl groups, which can form covalent bonds with the hydroxyl and amino groups of wool fibers under the catalysis of sodium hypophosphite, thereby introducing active carboxyl groups onto the wool fibers.

[0013] In one embodiment of the present application, in S1, the rolling reduction rate of the double-dip double-rolled treated wool is 80%-100%.

[0014] In one embodiment of the present application, in S1, the pre-baking is 60-80℃ pre-baking for 2-3 minutes, and the baking is 140-160℃ baking for 2-3 minutes.

[0015] In one embodiment of the present application, in S2, the concentration of the zirconium salt in the zirconium salt solution is 5-10 g / L.

[0016] In one embodiment of the present application, in S2, the zirconium salt is selected from one or more of zirconium tetrachloride, zirconium nitrate and zirconium sulfate, which forms coordination bonds with carboxyl, amino and the like on the pretreated wool fibers, thereby helping to improve the loading of MOF on the wool fibers.

[0017] In one embodiment of the present application, in S3, the concentration of the trimesic acid solution is 5-10 g / L, and the pH is 4.5-5.5; the pH regulator is sodium hydroxide. Trimesic acid has strong coordination chelation ability with zirconium salt, and the addition of sodium hydroxide adjusts the pH of the trimesic acid solution, thereby promoting the dissolution of trimesic acid.

[0018] In one embodiment of the present application, in S3, the concentration of 2,4,6-trichloropyrimidine in the treatment solution is 15-30 g / L, and the concentration of sodium bicarbonate is 20-30 g / L; the active chlorine of 2,4,6-trichloropyrimidine can react with the active carboxyl on the trimesic acid and wool fibers, thereby grafting MOF on the wool fibers through covalent bonds to improve the durability of the modified wool fabric; sodium bicarbonate is an alkaline reagent, which helps to promote the participation of the active chlorine of 2,4,6-trichloropyrimidine in the reaction.

[0019] In one embodiment of the present application, in S2 and S3, during the dipping process, the bath ratio is 1:30-50, the larger the bath ratio, the more uniform the treatment of the wool fabric, and too large a bath ratio will result in waste; the dipping temperature is 85-95℃, and the dipping time is 30-40 minutes; increasing the temperature and prolonging the time helps to improve the generation of MOF and its loading on the wool fabric.

[0020] In one embodiment of the present application, in S4, the number of repetitions is 2-4 times, and Zr-MOF nanometer flame retardant is loaded on the wool fabric in situ through coordination self-assembly; the more the number of assemblies, the higher the loading of Zr-MOF on the wool, and the weight gain is 5.7%-13.2%, which helps to improve the flame retardant performance of the wool fabric, but too high a number of assemblies will result in waste.

[0021] A second object of the present application is to provide a Zr-MOF-based durable flame-retardant and smoke-suppressing wool fabric prepared by the method.

[0022] The technical solution of the present application has the following advantages compared with the prior art:

[0023] (1) In the preparation method, citric acid can cross-link with the hydroxyl and amino groups of the wool fibers under the catalysis of sodium hypophosphite, thereby grafting active carboxyl groups on the wool fibers. The active carboxyl groups on the wool fibers can chelate with zirconium salt, thereby improving the loading and uniform distribution of Zr-MOF on the wool fabric.

[0024] (2) In the preparation method, a strong coordination bond can be formed between the zirconium salt and the trimesic acid, and Zr-MOF structures can be formed on the surface of the wool fabric through self-assembly. In the Zr-MOF organic-inorganic hybrid system, the zirconium salt and the trimesic acid can improve the flame-retardant properties of the wool fabric through synergistic flame-retardant effect. The zirconium salt and the carboxylic acid structure can catalyze the formation of a high-thermal-stability carbon layer from the aromatic structure in the trimesic acid ligand, thereby protecting the wool matrix. The porous channels of Zr-MOF form a "labyrinth effect" to adsorb smoke particles, thereby reducing the smoke release of the modified wool fabric and improving the fire safety.

[0025] (3) In the preparation method, if the Zr-MOF nanoparticles alone rely on the coordination bond with the carboxyl groups on the wool fabric, they cannot withstand water washing, resulting in poor flame-retardant durability. Therefore, 2,4,6-trichloropyrimidine is inserted into the Zr-MOF ligand. On the one hand, the active chlorine can form covalent bond with the carboxyl groups of the Zr-MOF ligand, the carboxyl groups and the amino groups on the wool fabric, thereby grafting the Zr-MOF nano flame retardant on the wool fabric through covalent bond, thereby improving the durability of the Zr-MOF loading on the wool fabric. On the other hand, 2,4,6-trichloropyrimidine has a nitrogen heterocyclic structure and has strong carbon-forming effect, which can be used as a synergistic flame-retardant structure to improve the flame-retardant properties of the modified wool fabric. BRIEF DESCRIPTION OF DRAWINGS

[0026] In order to make the content of the present application more easily understood, the present application will be further described in detail below according to specific embodiments of the present application and in conjunction with the accompanying drawings, in which:

[0027] Figure 1 The surface morphology of the unmodified wool fabric and the modified wool fabric in Test Example 1 of the present application is shown in the following table:

[0028] Figure 2 The total smoke generation of the unmodified wool fabric and the modified wool fabric in Test Example 2 of the present application is shown in the following table: DETAILED DESCRIPTION

[0029] The application will be further described in conjunction with the drawings and specific examples so that those skilled in the art can better understand the application and implement it, but the examples are not intended to limit the application.

[0030] In the present application, the bath ratio in the impregnation process in the examples and comparative examples is 1:40, unless otherwise specified.

[0031] In the present application, the pH adjuster for the aqueous solution of trimesic acid in the examples and comparative examples is sodium hydroxide, unless otherwise specified.

[0032] Example 1

[0033] The Zr-MOF-based persistent flame-retardant and smoke-suppressing wool fabric of the present application and the preparation method thereof specifically include the following steps:

[0034] S1, dissolve citric acid and sodium hypophosphite in water to obtain a pretreatment solution, then immerse the wool fabric in the pretreatment solution for 10 min, then perform two-dip-two-nip treatment with a pick-up rate of 90%, then pre-dry at 70°C for 2.5 min, and then bake at 150°C for 2.5 min to obtain a pretreated wool fabric; wherein the concentration of citric acid in the pretreatment solution is 40 g / L, and the concentration of sodium hypophosphite is 22 g / L.

[0035] S2, immerse the pretreated wool fabric in an aqueous solution of zirconium tetrachloride with a concentration of 8 g / L at 90°C for 35 min for modification treatment to obtain a modified wool fabric;

[0036] S3, immerse the modified wool fabric in an aqueous solution of trimesic acid with a pH of 5 and a concentration of 8 g / L at 90°C for 35 min for primary treatment; then dissolve 2,4,6-trichloropyrimidine and sodium bicarbonate in water to obtain a treatment solution, then immerse the modified wool fabric after the primary treatment in the treatment solution at 90°C for 35 min for secondary treatment to obtain a flame-retardant and smoke-suppressing wool fabric; wherein the concentration of 2,4,6-trichloropyrimidine in the treatment solution is 22 g / L, and the concentration of sodium bicarbonate is 25 g / L;

[0037] S4, repeat steps S2-S3 for 3 times to obtain a Zr-MOF-based persistent flame-retardant and smoke-suppressing wool fabric with a weight gain of about 9%.

[0038] Comparative Example 1

[0039] The same as Example 1, except that S1 treatment is not performed.

[0040] Comparative Example 2

[0041] The same as Example 1, except that S2 treatment is not performed.

[0042] Comparative Example 3

[0043] The procedure of Example 1 was basically followed except that the trimesic acid aqueous solution treatment was not performed in S3.

[0044] Comparative Example 4

[0045] The procedure of Example 1 was basically followed except that the treatment liquid treatment was not performed in S3.

[0046] Example 2

[0047] The Zr-MOF-based persistent flame-retardant and smoke-suppressing wool fabric and the preparation method thereof, specifically comprises the following steps:

[0048] S1, citric acid and sodium hypophosphite are dissolved in water to obtain a pretreatment liquid, then the wool fabric is immersed in the pretreatment liquid for 10 min, followed by two-dip-two-nip treatment with a pick-up rate of 80%, and then pre-drying at 60℃ for 3 min and baking at 140℃ for 3 min to obtain a pretreated wool fabric; wherein the concentration of citric acid in the pretreatment liquid is 30 g / L, and the concentration of sodium hypophosphite is 15 g / L.

[0049] S2, the pretreated wool fabric is immersed in a zirconium nitrate aqueous solution with a concentration of 5 g / L at 85℃ for 40 min for modification treatment to obtain a modified wool fabric;

[0050] S3, the modified wool fabric is immersed in a trimesic acid aqueous solution with a pH of 4.5 and a concentration of 5 g / L at 85℃ for 40 min for a first treatment; 2,4,6-trichloropyrimidine and sodium bicarbonate are dissolved in water to obtain a treatment liquid, then the modified wool fabric after the first treatment is immersed in the treatment liquid at 85℃ for 40 min for a second treatment to obtain a flame-retardant and smoke-suppressing wool fabric; wherein the concentration of 2,4,6-trichloropyrimidine in the treatment liquid is 15 g / L, and the concentration of sodium bicarbonate is 20 g / L;

[0051] S4, the steps of S2-S3 are repeated for 3 times to obtain a Zr-MOF-based persistent flame-retardant and smoke-suppressing wool fabric with a weight gain of about 6%.

[0052] Example 3

[0053] The Zr-MOF-based persistent flame-retardant and smoke-suppressing wool fabric and the preparation method thereof, specifically comprises the following steps:

[0054] S1, citric acid and sodium hypophosphite are dissolved in water to obtain a pretreatment liquid, then the wool fabric is immersed in the pretreatment liquid for 10 min, followed by two-dip-two-nip treatment with a pick-up rate of 100%, and then pre-drying at 80℃ for 2 min and baking at 160℃ for 2 min to obtain a pretreated wool fabric; wherein the concentration of citric acid in the pretreatment liquid is 50 g / L, and the concentration of sodium hypophosphite is 30 g / L.

[0055] S2, the wool fabric is pretreated and immersed in a zirconium sulfate aqueous solution with a concentration of 10 g / L at 95°C for 30 min for modification treatment to obtain a modified wool fabric;

[0056] S3, the modified wool fabric is immersed in a 2,4,6-trichloropyrimidine aqueous solution with a pH of 5.5 and a concentration of 10 g / L at 95°C for 30 min for primary treatment; 2,4,6-trichloropyrimidine and sodium bicarbonate are dissolved in water to obtain a treatment solution, and then the modified wool fabric after the primary treatment is immersed in the treatment solution at 95°C for 30 min for secondary treatment to obtain a flame-retardant and smoke-suppressing wool fabric; wherein the concentration of 2,4,6-trichloropyrimidine in the treatment solution is 30 g / L, and the concentration of sodium bicarbonate is 30 g / L;

[0057] S4, the steps S2-S3 are repeated for 3 times to obtain a Zr-MOF-based persistent flame-retardant and smoke-suppressing wool fabric with a weight gain of about 13.0%.

[0058] Test Example 1

[0059] Based on Example 1, the unmodified wool fabric and the Zr-MOF-based persistent flame-retardant and smoke-suppressing wool fabric (modified wool fabric) are characterized, and the results are shown in Figure 1 Figure 1 It can be seen from

[0060] Test Example 2

[0061] The flame-retardant properties and the like of the wool fabrics prepared in Examples 1-3 and Comparative Examples 1-4 are tested:

[0062] The limiting oxygen index (LOI) of the fabric is determined according to the GB / T 5454-1997 standard “Textile Burning Property Experiment Oxygen Index Method”;

[0063] The damage length of the fabric is determined according to the GB / T 5455-2014 standard “Textile Burning Property Vertical Direction Damage Length, Smoldering and Afterburning Time Determination”;

[0064] The washing method of the fabric is evaluated according to the AATCC 61-2006 standard “Accelerated Test for Home and Commercial Washing Color Fastness”;

[0065] The burning property of the fabric is evaluated according to the GB / T 17591-2006 standard “Flame-retardant Fabric”;

[0066] ​The total smoke generation of the fabric was tested by using a cone calorimeter with a heat flux of 35 kW / m 2 ;

[0067] Figure 2 The total smoke generation of the unmodified wool fabric and the modified wool fabric of Example 1 was measured;

[0068] The relevant properties of the unmodified wool fabric and the modified wool fabric were measured and shown in Table 1:

[0069] Table 1

[0070]

[0071] From Figure 2 As can be seen from Table 1, the limiting oxygen index of the unmodified wool fabric is only 23.1%, and it is completely burned in the vertical burning test, with a damage length of 30 cm, and poor flame retardant performance; the total smoke generation of the unmodified wool fabric reaches 0.98 m 2 , which is a serious fire hazard. The limiting oxygen index of the flame-retardant and smoke-suppressing wool fabric of the example is not less than 31.5%, the damage length is not higher than 11.2 cm, the damage length after 20 times of washing is not higher than 14.7 cm, and the total smoke generation is not higher than 0.33 m 2 , which indicates that the flame-retardant and smoke-suppressing wool fabric has excellent flame retardant performance, washing resistance and smoke suppression performance.

[0072] In addition, the analysis of Comparative Example 1 and Example 1 shows that the modified wool fabric without citric acid pretreatment can obtain good flame retardant performance, but the flame retardant efficiency is slightly reduced, and it cannot withstand 20 times of washing, because the citric acid modification can provide more carboxyl groups for the wool, which helps to improve the adsorption of zirconium salt and fastness.

[0073] The analysis of Comparative Example 2 and Example 1 shows that the wool fabric without zirconium salt treatment cannot obtain good flame retardant performance.

[0074] The analysis of Comparative Example 3 and Example 1 shows that the flame retardant performance of the wool fabric without treatment of the organic ligand trimesic acid is poor, only B2 level, and loses the flame retardant effect after 5 times of washing, which indicates that there is a synergistic flame retardant effect between trimesic acid and zirconium salt, and the coordination chelation between the two helps to improve the adsorption of Zr-MOF on the wool; in addition, the smoke suppression performance of the modified wool fabric is poor, because Zr-MOF with a porous structure cannot be generated on the surface of the wool fabric, and smoke particles cannot be adsorbed, resulting in poor smoke suppression performance.

[0075] The analysis of Comparative Example 4 and Example 1 shows that the flame retardant property of the modified wool fabric without 2,4,6-trichloropyrimidine treatment is reduced, because 2,4,6-trichloropyrimidine has a synergistic flame retardant effect, loses the flame retardant effect after 5 times of home washing, only reaches B2 level, and the damage length reaches 30 cm after 20 times of washing, with poor durability.

[0076] Obviously, the above examples are merely illustrative and not limiting. Based on the above description, those skilled in the art can make other different forms of changes or variations. It is not necessary and impossible to enumerate all the embodiments. The obvious changes or variations derived therefrom are still within the protection scope of the present application.

Claims

1. A method for preparing a durable flame-retardant and smoke-suppressing wool fabric based on Zr-MOF, characterized in that, Includes the following steps: S1. The wool fabric is immersed in a pretreatment solution for two dips and two nips, and then pre-dried and baked to obtain the pretreated wool fabric; the pretreatment solution includes citric acid, sodium hypophosphite and water; S2. The pretreated wool fabric described in S1 is immersed in a zirconium salt solution for modification treatment to obtain a modified wool fabric. S3. The modified wool fabric described in S2 is sequentially immersed in a pyromellitic acid solution and a treatment liquid for treatment to obtain a flame-retardant and smoke-suppressing wool fabric; the treatment liquid includes 2,4,6-trichloropyrimidine, sodium bicarbonate and water; S4. Repeat S2-S3 to obtain the Zr-MOF-based durable flame-retardant and smoke-suppressing wool fabric.

2. The method for preparing a durable flame-retardant and smoke-suppressing wool fabric based on Zr-MOF according to claim 1, characterized in that, In S1, the concentration of citric acid in the pretreatment solution is 30 g / L-50 g / L, and the concentration of sodium hypophosphite is 15 g / L-30 g / L.

3. The method for preparing a durable flame-retardant and smoke-suppressing wool fabric based on Zr-MOF according to claim 1, characterized in that, In S1, the roll residue after the two-dip and two-roll process is 80%-100%.

4. The method for preparing a durable flame-retardant and smoke-suppressing wool fabric based on Zr-MOF according to claim 1, characterized in that, In S1, the pre-baking is pre-baking at 60℃-80℃ for 2-3 minutes, and the baking is baking at 140℃-160℃ for 2-3 minutes.

5. The method for preparing a durable flame-retardant and smoke-suppressing wool fabric based on Zr-MOF according to claim 1, characterized in that, In S2, the concentration of zirconium salt in the zirconium salt solution is 5 g / L-10 g / L.

6. The method for preparing a durable flame-retardant and smoke-suppressing wool fabric based on Zr-MOF according to claim 1, characterized in that, In S2, the zirconium salt is selected from one or more of zirconium tetrachloride, zirconium nitrate, and zirconium sulfate.

7. The method for preparing a durable flame-retardant and smoke-suppressing wool fabric based on Zr-MOF according to claim 1, characterized in that, In S3, the concentration of the pyromellitic acid solution is 5 g / L-10 g / L, and the pH is 4.5-5.

5.

8. The method for preparing a durable flame-retardant and smoke-suppressing wool fabric based on Zr-MOF according to claim 1, characterized in that, In S3, the concentration of 2,4,6-trichloropyrimidine in the treatment solution is 15 g / L-30 g / L, and the concentration of sodium bicarbonate is 20 g / L-30 g / L.

9. The method for preparing a durable flame-retardant and smoke-suppressing wool fabric based on Zr-MOF according to claim 1, characterized in that, In S2 and S3, the bath ratio is 1:30-50, the impregnation temperature is 85℃-95℃, and the impregnation time is 30min-40min.

10. The Zr-MOF-based durable flame-retardant and smoke-suppressing wool fabric prepared by the method of any one of claims 1-9.

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