Aramid fiber flame-retardant fabric and preparation method thereof

Abstract

The invention relates to an aramid fiber flame-retardant fabric and a preparation method thereof, and belongs to the technical field of fabric preparation, and the preparation method specifically comprises the following steps: pretreating aramid fibers, blending antistatic fibers and para-aramid fibers, and spinning warp and weft yarns; the yarn is subjected to padding and heat treatment through the flame-retardant finishing liquid to obtain flame-retardant yarn; weaving gray fabric with flame-retardant yarns, and setting the warp and weft density; and tentering, sizing and rolling the gray fabric to obtain the aramid fiber flame-retardant fabric. The advantages of the meta-aramid, the para-aramid and the antistatic fibers are combined to blend the warp and the weft, so that the strength, the flame retardance and the antistatic performance of the fabric are enhanced. The modified carboxylated cellulose nanocrystal, the metal oxide and the decabromodiphenyl ethane are compounded into the flame retardant, so that the flame retardant effect is improved, and the cost is reduced. The fibers treated by the alkali liquor have strong affinity with the flame retardant, the nanocrystalline reinforces the surfaces of the fibers, the adhesion of the flame retardant is enhanced by the tissue pattern design, and the flame retardant property of the aramid fabric is further improved.

Description

Technical Field

[0001] The present application relates to the technical field of fabric preparation, and more specifically, to an aramid flame-retardant fabric and a preparation method thereof. Background Art

[0002] Aramid flame-retardant fabrics, especially those based on Kevlar fibers, have broad application prospects in fields such as protective clothing, aerospace, and automotive manufacturing due to their high strength, high modulus, and other properties. However, the prior art still faces many challenges in preparing such fabrics. First, in order to improve the flame-retardant performance of the fabric, a flame-retardant finishing step is usually set in traditional processes. However, this method has obvious limitations. The flame-retardant finishing agent can only penetrate a very thin layer on the fabric surface, and for fibers that already have flame-retardant effects, such as Kevlar fibers, the improvement of their flame-retardant performance is not obvious. Second, the bonding force of Kevlar fibers is weak, which is a long-standing technical problem. When the fibers rub against each other, Kevlar fibers are prone to fibrillization or fiber splitting, which easily leads to a decrease in the overall strength of the fabric. This insufficient bonding force between fibers limits the application of Kevlar fibers in high-performance fabrics.

[0003] The prior art faces multiple challenges such as limited flame-retardant finishing effects and decreased mechanical properties when preparing aramid flame-retardant fabrics. Therefore, developing a new type of aramid flame-retardant fabric and its preparation method that can significantly improve the flame-retardant performance while maintaining the mechanical properties of the fabric has become an urgent technical problem to be solved.

[0004] Based on the above statements, the present application provides an aramid flame-retardant fabric and a preparation method thereof. Summary of the Invention

[0005] To solve the problems raised in the background art, the present application provides an aramid flame-retardant fabric and a preparation method thereof.

[0006] The present application provides a preparation method for an aramid flame-retardant fabric, adopting the following technical solution:

[0007] A preparation method for an aramid flame-retardant fabric includes the following preparation steps:

[0008] S1. Fiber pretreatment: The aramid fibers are washed and then treated with an alkali solution to obtain pretreated aramid fibers.

[0009] S2. Yarn preparation: After mixing the pretreated aramid fibers with antistatic fibers, the warp yarns are spun through the steps of bale opening, carding, drawing, roving, spinning, winding, and twisting; the pretreated aramid fibers are mixed with para-aramid and antistatic fibers, and the weft yarns are spun through the steps of bale opening, carding, drawing, roving, spinning, winding, and twisting.

[0010] S3. Flame retardant finishing of yarns: The warp and weft yarns are impregnated in a flame retardant finishing solution at a mass-to-volume ratio of 1 g:(5 - 10) mL for padding treatment, two dips and two rolls, with the pick-up rate set at 65 - 80% and then taken out. Subsequently, they are heat-treated at 70 - 80 °C for 20 - 30 minutes to obtain flame retardant warp yarns and flame retardant weft yarns respectively;

[0011] S4. Fabric weaving: After determining the fabric structure, the flame retardant warp yarns and flame retardant weft yarns are used for winding, warping, sizing, and reed threading processes to weave a grey fabric;

[0012] S5. Fabric post-treatment: The grey fabric obtained in step S4 is subjected to tentering, setting, and rolling processes to obtain an aramid flame retardant fabric.

[0013] Further, in step S1, the pretreated aramid fibers are specifically prepared by the following steps:

[0014] S11. The aramid fibers are soaked in absolute ethanol and ultrasonically treated for 2 - 3 hours, then filtered repeatedly five times with deionized water using a suction filter. After that, they are placed in an electric blast drying oven at 90 - 100 °C until dry, and then put into a drying dish for standby;

[0015] S12. The aramid fibers obtained in step S11 are impregnated in an alkaline solution at a mass-to-volume ratio of 1 g:(10 - 20) mL, and stirred at 70 - 80 °C and a rate of 30 - 90 rpm for 2 - 3 hours using a magnetic stirrer. Subsequently, they are filtered, and the filtrate is filtered three times with deionized water and dried at 80 - 90 °C to prepare the pretreated aramid fibers.

[0016] During the above reaction process, the aramid fibers are washed with an ethanol solution to remove residual ethanol and other possible contaminants on the fiber surface, and then used for standby. Subsequently, the pretreated aramid fibers are etched with an alkaline solution to prepare the pretreated aramid fibers. In an alkaline environment, the OH - in the system reacts with the carbon-oxygen double bond in the fiber structure, causing the aramid fibers to hydrolyze, introducing carboxyl oxygen-containing groups into the system, and increasing the fiber roughness and hydrophilicity.

[0017] Further, in step S11, the aramid fibers are meta-aramid.

[0018] Further, in step S12, the alkaline solution is a 5 - 20 wt% NaOH solution.

[0019] Further, in step S2, the warp yarns are obtained by blending pretreated aramid fibers and antistatic fibers at a mass ratio of (95 - 98):(2 - 5).

[0020] Furthermore, in step S2, the weft yarn is obtained by blending pretreated aramid fiber, para-aramid fiber and antistatic fiber in a mass ratio of (90-95):(3-7):(2-3).

[0021] Furthermore, in step S3, the flame retardant finishing liquid is specifically prepared by the following steps:

[0022] S31, adding 10-15 mg of 2-morpholineethanesulfonic acid to 30 mL of sterile deionized water, and adjusting the pH value of the system to 5.5-6.7 with a NaOH solution to obtain a 2-morpholineethanesulfonic acid buffer; dissolving (10-12) g of carboxylated cellulose nanocrystals, 0.2 g of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride, 0.1 g of N-hydroxysuccinimide and (0.5-1) g of dopamine hydrochloride in 10 mL of 2-morpholineethanesulfonic acid buffer, and stirring at room temperature under an inert gas atmosphere for 20-30 hours to obtain modified cellulose nanocrystals;

[0023] S32. Mix the composite flame retardant, modified cellulose nanocrystals, surfactant and penetrant in deionized water at 30-40°C at a rate of 30-90rpm for 40-60 minutes to obtain a flame retardant finishing liquid; wherein the amount of the composite flame retardant is 350-370g / L, the amount of the modified cellulose nanocrystal is 1-2g / L, the amount of the surfactant is 4-6g / L, and the amount of the penetrant is 0.1-0.5g / L.

[0024] In the above reaction process, under the action of EDC and NHS, the carboxyl groups on the carboxylated cellulose nanocrystals are combined with the amino groups on dopamine hydrochloride, an amide bond is introduced on the carboxylated cellulose nanocrystals, and catechol functional groups are grafted to prepare modified cellulose nanocrystals. Subsequently, a flame retardant finishing agent is formed with a composite flame retardant, a surfactant and a penetrant.

[0025] Furthermore, in step S32, the composite flame retardant is prepared by compounding decabromodiphenylethane and a metal oxide in a mass ratio of (2.5-3.5): 1. The metal oxide is at least one of antimony trioxide, aluminum oxide, zinc oxide and magnesium oxide.

[0026] Furthermore, in step S4, the tissue structure is at least one of a basket weave, a lattice weave, a diamond weave and a honeycomb weave.

[0027] In summary, this application has the following beneficial effects:

[0028] (1) In the technical solution of the present invention, the warp yarn is spun from pretreated aramid fiber and antistatic fiber, and the para-aramid is added to the weft yarn. Such a design combines the advantages of different aramid fibers. Meta-aramid has excellent heat resistance, flame retardancy and chemical stability, while para-aramid has characteristics such as high strength and high modulus. The addition of antistatic fiber effectively prevents the generation of static electricity, improving the comfort and safety of the fabric. Through reasonable blending by mass ratio, the warp and weft yarns not only ensure high strength but also have good flame retardancy and antistatic properties, meeting the performance requirements of fabrics in specific fields.

[0029] (2) In the technical solution of the present invention, a flame retardant finishing step is carried out on the yarn, and modified carboxylated cellulose nanocrystals are used as part of the flame retardant finishing agent in the flame retardant finishing agent. The modified cellulose nanocrystals contain catechol structures, which can chelate the flame retardant components in the system to further improve the flame retardant improvement effect of the flame retardant finishing agent on the fiber. Specifically, for the metal oxide flame retardant in the compound system, the dispersion effect of the oxide in the system can be improved through metal-ion interactions. For the decabromodiphenylethane component, its dispersion effect can be improved through π-π interactions. In addition, the principle of the synergistic compounding of the flame retardants used in the present invention lies in that different flame retardants can interact with each other to form a more effective flame retardant system. Decabromodiphenylethane, as a brominated flame retardant, has excellent flame retardant effects; while metal oxides can catalyze the chemical reactions in the flame retardant process, improving the flame retardant efficiency. Through reasonable compounding by mass ratio, the composite flame retardant can give full play to their respective advantages to form a more efficient flame retardant system. This compound flame retardant not only improves the flame retardant performance of the fabric but also reduces the usage amount of the flame retardant, saving costs.

[0030] (3) In the technical solution of the present invention, the fiber after being treated with alkali solution is impregnated in the flame retardant finishing agent for treatment. The surface of the modified carboxylated cellulose nanocrystals contains amide structures of the same type as the fiber, having good affinity, which can improve the deposition and adhesion of the flame retardant on the fiber surface. And during the flame retardant finishing process of the yarn, the damaged fiber surface can be reinforced through the π-π interaction between the modified cellulose nanocrystals and the aramid fiber, improving the mechanical properties of the fiber. And by designing and manufacturing the tissue patterns on the fabric, the adhesion effect and the retention effect of the flame retardant on the fabric are improved, further enhancing the flame retardant effect of the obtained aramid fabric. Description of the Drawings

[0031] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0032] Figures 1-7 It is the organizational chart of an aramid flame-retardant fabric and its preparation method of the present invention. Specific embodiments

[0033] Next, in combination with the embodiments of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the scope of protection of the present invention.

[0034] In the specific embodiments of this application:

[0035] Meta-aramid: Aramid 1313, linear density 1.68 dtex.

[0036] Para-aramid: Aramid 1414, linear density 1.44 dtex.

[0037] Antistatic fiber: Polyester DTY conductive filament, provided by Zhejiang Datong Textile Co., Ltd., model 75D.

[0038] Carboxylated cellulose nanocrystals: diameter 4 - 10 nm, length 100 - 500 nm, crystal structure is cellulose type I.

[0039] The surfactant used is sodium lauryl sulfate; the penetrant used is JFC, brand name Haishihua.

[0040] Antimony trioxide: CAS No. 1309 - 64 - 4, purity 99%, average particle size 1 μm.

[0041] Zinc oxide: purity 99%, average particle size 0.1 μm.

[0042] In the weaving structure, Figure 1 , Figure 2 , Figure 3 The number of harnesses required for weaving is 6, Figure 4 , Figure 5 , Figure 6 , Figure 7 The number of harnesses required for weaving is 8.

[0043] Example 1

[0044] A preparation method of an aramid flame-retardant fabric, comprising the following preparation steps:

[0045] S1. Fiber pretreatment: The aramid fiber is washed and then treated with an alkali solution to obtain pretreated aramid fiber. The specific operation is:

[0046] S11. Immerse the aramid fiber in absolute ethanol and perform ultrasonic treatment for 2 hours. Use a suction filter to filter it repeatedly five times with deionized water, and then place it in an electric blast drying oven at 90 °C until it is dry. Put it in a drying dish for later use. Among them, the aramid fiber is meta-aramid;

[0047] S12. Immerse the aramid fiber obtained in step S11 in the alkaline solution according to the mass-volume ratio of 1 g:10 mL. Use a magnetic stirrer to stir at 70 °C and a rate of 30 rpm for 2 hours, then filter, and filter the filtrate three times with deionized water, and dry it at 80 °C to prepare the pretreated aramid fiber. Among them, the alkaline solution is 5 wt% NaOH solution.

[0048] S2. Yarn preparation: After mixing the pretreated aramid fiber with the antistatic fiber, spin the warp yarn through the steps of bale opening, carding, drawing, roving, spinning, winding, and twisting; Mix the pretreated aramid fiber with para-aramid and antistatic fiber, and spin the weft yarn through the steps of bale opening, carding, drawing, roving, spinning, winding, and twisting. Among them, in the bale opening process, the speed of the single-drum bale opener is 1500 rpm, the speed of the feed roller is 1550 rpm, and the distance between the beater and the feed roller is 11 mm; In the carding process, the speed of the cylinder is 300 rpm and the speed of the licker-in is 330 rpm; In the drawing process, the number of merged strands is 5; In the roving process, the roving count is 10 g / 10 m; In the spinning process, the total draft multiple is 20 times and the twist is 50 turns / 10 cm. Among them, the warp yarn is spun from the pretreated aramid fiber and the antistatic fiber according to the mass ratio of 95:5; The weft yarn is spun from the pretreated aramid fiber, para-aramid and antistatic fiber according to the mass ratio of 90:7:3.

[0049] S3. Flame retardant finishing of yarn: Immerse the warp yarn and weft yarn with a count of 12 Ne in the flame retardant finishing solution according to the mass-volume ratio of 1 g:5 mL for padding treatment, dip two times and pad two times, set the liquor pickup to 65%, take it out, and then heat treat it at 70 °C for 20 minutes to obtain the flame retardant warp yarn and the flame retardant weft yarn respectively;

[0050] Among them, the flame retardant finishing solution is specifically prepared by the following steps:

[0051] S31. Add 10 mg of 2-morpholinoethanesulfonic acid to 30 mL of sterile deionized water, and use NaOH solution to adjust the pH value of the system to 5.5 to obtain 2-morpholinoethanesulfonic acid buffer solution; Dissolve 10 g of carboxylated cellulose nanocrystals, 0.2 g of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride, 0.1 g of N-hydroxysuccinimide and 0.5 g of dopamine hydrochloride in 10 mL of 2-morpholinoethanesulfonic acid buffer solution, and stir at room temperature and in a nitrogen atmosphere for 20 hours to obtain modified cellulose nanocrystals;

[0052] S32, mixing the composite flame retardant, modified cellulose nanocrystals, surfactant, and penetrant in deionized water at 30° C. and at a speed of 30 rpm for 40 minutes to obtain a flame retardant finishing liquid;

[0053] Among them, the usage of composite flame retardant is 350g / L, the usage of modified cellulose nanocrystal is 1g / L, the usage of surfactant is 4g / L, and the usage of penetrant is 0.1g / L;

[0054] The composite flame retardant is obtained by compounding decabromodiphenylethane and metal oxide in a mass ratio of 2.5:1; the metal oxide is antimony trioxide.

[0055] S4. Fabric weaving: After determining the organizational structure, use flame-retardant warp yarn and flame-retardant weft yarn to carry out winding, warping, and reeding processes to weave grey cloth, setting the warp density to 33 / cm and the weft density to 24 / cm; Figure 1 The square plain weave shown in the figure is woven; in the winding process, the tension ring of the winding machine is adjusted to 30g; in the warping process, a high-speed warping machine is used, and the parameters are: the number of cars is 450m / min, and the yarn pressing pressure is 0.5Mpa; in the weaving process, a rapier loom is used for weaving, and the parameters are: speed 420m / min, opening time 300°, and opening height 30mm.

[0056] S5, fabric finishing: the grey fabric obtained in step S4 is subjected to the steps of tentering, shaping and rolling to obtain an aramid flame-retardant fabric.

[0057] Example 2

[0058] A method for preparing an aramid flame-retardant fabric comprises the following preparation steps:

[0059] S1. Fiber pretreatment: After washing, the aramid fiber is treated with alkali solution to prepare pretreated aramid fiber. The specific operation is as follows:

[0060] S11, the aramid fiber is soaked in anhydrous ethanol and ultrasonically treated for 2 hours, and filtered with deionized water using a suction filter for five times, and then placed in an electric blast drying oven at 90° C. until dry, and placed in a drying dish for standby use; wherein the aramid fiber is meta-aramid;

[0061] S12. Immerse the aramid fiber obtained in step S11 in an alkaline solution at a mass volume ratio of 1 g:15 mL, stir with a magnetic stirrer at 70°C and 60 rpm for 2.5 hours, then filter, and filter the filtrate three times with deionized water, and dry at 90°C to prepare pretreated aramid fiber; wherein the alkaline solution is a 10wt% NaOH solution.

[0062] S2. Yarn Preparation: After mixing the pretreated aramid fiber and antistatic fiber, warp yarns are spun through the steps of bale opening, carding, drawing, roving, spinning, winding, and twisting; weft yarns are spun by mixing the pretreated aramid fiber, para-aramid, and antistatic fiber and going through the steps of bale opening, carding, drawing, roving, spinning, winding, and twisting. Among them, in the bale opening process, the speed of the single-drum opener is 1500 rpm, the speed of the feed roller is 1550 rpm, and the gauge between the beater and the feed roller is 11 mm; in the carding process, the speed of the cylinder is 300 rpm and the speed of the licker-in is 330 rpm; in the drawing process, the number of strands combined is 5; in the roving process, the roving count is 10 g / 10 m; in the spinning process, the total draft multiple is 20 times and the twist is 50 turns / 10 cm. Among them, the warp yarn is obtained by blending the pretreated aramid fiber and antistatic fiber in a mass ratio of 97:3; the weft yarn is obtained by blending the pretreated aramid fiber, para-aramid, and antistatic fiber in a mass ratio of 93:5:2.

[0063] S3. Flame Retardant Finishing of Yarns: The warp yarns and weft yarns are impregnated in the flame retardant finishing solution according to the mass-to-volume ratio of 1 g:8 mL for padding treatment, double padding and double squeezing, and taken out with a squeeze ratio of 75%, and then heat-treated at 80 °C for 25 minutes to obtain flame-retardant warp yarns and flame-retardant weft yarns respectively;

[0064] Among them, the flame retardant finishing solution is specifically prepared by the following steps:

[0065] S31. Add 12 mg of 2-morpholinoethanesulfonic acid to 30 mL of sterile deionized water, and use NaOH solution to adjust the pH value of the system to 6.1 to obtain 2-morpholinoethanesulfonic acid buffer solution; dissolve 11 g of carboxylated cellulose nanocrystals, 0.2 g of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride, 0.1 g of N-hydroxysuccinimide, and 0.8 g of dopamine hydrochloride in 10 mL of 2-morpholinoethanesulfonic acid buffer solution, and stir at room temperature and under a nitrogen atmosphere for 25 hours to obtain modified cellulose nanocrystals;

[0066] S32. Mix the composite flame retardant, modified cellulose nanocrystals, surfactant, and penetrant in deionized water at 35 °C at a rate of 60 rpm for 50 minutes to obtain the flame retardant finishing solution;

[0067] Among them, the dosage of the composite flame retardant is 360 g / L, the dosage of the modified cellulose nanocrystals is 1.5 g / L, the dosage of the surfactant is 5 g / L, and the dosage of the penetrant is 0.3 g / L;

[0068] Among them, the composite flame retardant is prepared by compounding decabromodiphenylethane and metal oxide in a mass ratio of 3:1; the metal oxide is antimony trioxide.

[0069] S4. Fabric Weaving: After determining the fabric structure, use flame-retardant warp yarns and flame-retardant weft yarns to perform processes such as winding, warping, sizing, and reed threading to weave a grey fabric, with the warp density set at 33 / cm and the weft density at 24 / cm; weave according to the check pattern shown in Figure 2 . In the winding process, adjust the tension ring of the winding machine to 30 g; in the warping process, use a high-speed warping machine with parameters: the number of turns is 450 m / min, and the yarn pressing pressure is 0.5 Mpa; in the weaving process, use a rapier loom for weaving with parameters: speed 420 m / min, shedding time 300°, and shedding height 30 mm.

[0070] S5. Fabric Post-treatment: Perform processes such as stenter setting, heat setting, and rolling on the grey fabric obtained in step S4 to obtain an aramid flame-retardant fabric.

[0071] Example 3

[0072] A method for preparing an aramid flame-retardant fabric, comprising the following preparation steps:

[0073] S1. Fiber Pretreatment: Wash the aramid fibers and then treat them with an alkali solution to prepare pretreated aramid fibers. The specific operations are as follows:

[0074] S11. Immerse the aramid fibers in absolute ethanol and perform ultrasonic treatment for 3 hours. Use a suction filter to filter repeatedly five times with deionized water, then place them in an electric blast drying oven at 100 °C until dry, and put them in a drying dish for standby; among them, the aramid fibers are meta-aramid.

[0075] S12. Immerse the aramid fibers obtained in step S11 in an alkaline solution according to a mass-to-volume ratio of 1 g:20 mL. Use a magnetic stirrer to stir at 80 °C and a rate of 90 rpm for 3 hours, then filter, and filter the obtained product three times with deionized water and dry it at 90 °C to prepare pretreated aramid fibers; among them, the alkaline solution is a 20 wt% NaOH solution.

[0076] S2. Yarn Preparation: After mixing the pretreated aramid fibers and antistatic fibers, warp yarns are spun through the steps of bale opening, carding, drawing, roving, spinning, winding, and twisting; the pretreated aramid fibers are mixed with para-aramid and antistatic fibers, and weft yarns are spun through the steps of bale opening, carding, drawing, roving, spinning, winding, and twisting; among them, in the bale opening process, the speed of the single-drum bale opener is 1500 rpm, the feeding roller speed is 1550 rpm, and the distance between the beater and the feeding roller is 11 mm; in the carding process, the speed of the cylinder is 300 rpm, and the speed of the licker-in is 330 rpm; in the drawing process, the number of combined strands is 5; in the roving process, the roving count is 10 g / 10 m; in the spinning process, the total draft multiple is 20 times, and the twist is 50 turns / 10 cm; among them, the warp yarns are obtained by blending the pretreated aramid fibers and antistatic fibers according to a mass ratio of 98:2; the weft yarns are obtained by blending the pretreated aramid fibers, para-aramid, and antistatic fibers according to a mass ratio of 95:3:2.

[0077] S3. Yarn Flame Retardant Finishing: The warp yarns and weft yarns are impregnated in the flame retardant finishing solution according to a mass-volume ratio of 1 g:10 mL for padding treatment, two-padding and two-rolling, with the squeeze ratio set at 80% and then taken out, and then heat-treated at 80 °C for 30 minutes to obtain flame-retardant warp yarns and flame-retardant weft yarns respectively;

[0078] Among them, the flame retardant finishing solution is specifically prepared by the following steps:

[0079] S31. Add 15 mg of 2-morpholinoethanesulfonic acid to 30 mL of sterile deionized water, and use NaOH solution to adjust the pH value of the system to 6.7 to obtain 2-morpholinoethanesulfonic acid buffer solution; dissolve 12 g of carboxylated cellulose nanocrystals, 0.2 g of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride, 0.1 g of N-hydroxysuccinimide, and 1 g of dopamine hydrochloride in 10 mL of 2-morpholinoethanesulfonic acid buffer solution, and stir at room temperature under a nitrogen atmosphere for 30 hours to obtain modified cellulose nanocrystals;

[0080] S32. Mix the composite flame retardant, modified cellulose nanocrystals, surfactant, and penetrant in deionized water at 40 °C at a rate of 90 rpm for 60 minutes to obtain the flame retardant finishing solution;

[0081] Among them, the usage amount of the composite flame retardant is 370 g / L, the usage amount of the modified cellulose nanocrystals is 2 g / L, the usage amount of the surfactant is 6 g / L, and the usage amount of the penetrant is 0.5 g / L;

[0082] Among them, the composite flame retardant is prepared by compounding decabromodiphenylethane and metal oxide according to a mass ratio of 3.5:1; the metal oxide is zinc oxide.

[0083] S4. Fabric weaving: After determining the organizational structure, use flame-retardant warp yarn and flame-retardant weft yarn to carry out winding, warping, sizing, and reeding to weave grey cloth, with the warp density set to 33 / cm and the weft density set to 24 / cm; Figure 3 The square plain weave shown in the figure is woven; in the winding process, the tension ring of the winding machine is adjusted to 30g; in the warping process, a high-speed warping machine is used, and the parameters are: the number of cars is 450m / min, and the yarn pressing pressure is 0.5Mpa; in the weaving process, a rapier loom is used for weaving, and the parameters are: speed 420m / min, opening time 300°, and opening height 30mm.

[0084] S5, fabric finishing: the grey fabric obtained in step S4 is subjected to the steps of tentering, shaping and rolling to obtain an aramid flame-retardant fabric.

[0085] Example 4

[0086] The difference between this embodiment and embodiment 1 is that the woven structure used in this embodiment is Figure 4 Basket weave shown.

[0087] Example 5

[0088] The difference between this embodiment and embodiment 1 is that the woven structure used in this embodiment is Figure 5 The square grid organization shown.

[0089] Example 6

[0090] The difference between this embodiment and embodiment 1 is that the woven structure used in this embodiment is Figure 6 The diamond-shaped organization shown.

[0091] Example 7

[0092] The difference between this embodiment and embodiment 1 is that the woven structure used in this embodiment is Figure 7 The honeycomb organization shown.

[0093] Comparative Example 1

[0094] The difference between this comparative example and Example 1 is that the weaving structure used in this comparative example is 2 / 1 twill.

[0095] Comparative Example 2

[0096] The difference between this comparative example and Example 1 is that in step S1 of this comparative example, 20wt% sulfuric acid solution is used instead of alkali solution to pretreat the aramid fiber. The specific operation is as follows:

[0097] Comparative Example 3

[0098] The difference between this comparative example and Example 1 is that in step S2 of this comparative example, the weft yarn is obtained by blending pretreated aramid fiber, meta-aramid, and antistatic fiber in a mass ratio of 95:3:2.

[0099] Comparative Example 4

[0100] The difference between this comparative example and Example 1 is that in step S3 of this comparative example, the flame retardant finishing liquid is obtained by mixing a composite flame retardant, a surfactant, and a penetrant in deionized water at 30 °C at a rate of 30 rpm for 40 minutes;

[0101] wherein, the usage amount of the composite flame retardant is 350 g / L, the usage amount of the surfactant is 5 g / L, and the usage amount of the penetrant is 0.1 g / L;

[0102] Comparative Example 5

[0103] The difference between this comparative example and Example 1 is that in step S3 of this comparative example, carboxylated cellulose nanocrystals are used instead of modified cellulose nanocrystals to prepare the flame retardant finishing liquid. Specifically, the flame retardant finishing liquid is obtained by mixing a composite flame retardant, carboxylated cellulose nanocrystals, a surfactant, and a penetrant in deionized water at 30 °C at a rate of 30 rpm for 40 minutes;

[0104] wherein, the usage amount of the composite flame retardant is 350 g / L, the usage amount of carboxylated cellulose nanocrystals is 1 g / L, the usage amount of the surfactant is 4 g / L, and the usage amount of the penetrant is 0.1 g / L.

[0105] Performance Test

[0106] Now, the tensile strength test and oxygen index test are carried out on the flame retardant fabrics prepared in Examples 1-7 and Comparative Examples 1-5 of this application to evaluate the mechanical properties and flame retardant properties of the fabrics. The tests are carried out according to the methods described in GB / T3923.1-2013 "Textiles - Tensile properties of fabrics - Part 1: Determination of breaking force and elongation at break" and GB / T5454-1997 "Textiles - Test method for burning performance - Oxygen index method". The specific performance test results are shown in Table 1 below:

[0107] Table 1

[0108]

[0109]

[0110] As can be seen from the results shown in Table 1 above: The comprehensive performance of the aramid flame-retardant fabrics prepared in Examples 1-7 of this application is significantly better than that of the products prepared in Comparative Examples 1-5. That is, within the limited technical solutions of this application, the comprehensive performance of the prepared aramid flame-retardant fabrics is excellent. Specifically, the product prepared in Example 2 has the best breaking strength and flame-retardant effect, and the product prepared in Example 3 has the best elongation at break.

[0111] As can be seen from the results in Comparative Example 1, matching a specially designed pattern can improve the stability and flame-retardant effect of the flame-retardant component on the fabric. As can be seen from the results in Comparative Example 2, aramid fibers are more sensitive to acid than to alkali, making them more prone to hydrolysis under acidic conditions. Therefore, the strength decreases more significantly under acidic conditions, and while the surface roughness is increased, the mechanical properties of the product decrease more significantly. As can be seen from the results in Comparative Example 3, the covalent bonds of benzene rings in meta-aramid do not produce a conjugated effect, and the interaction with the modified cellulose nanocrystals in the flame-retardant finishing agent decreases. Using a small amount of para-aramid in the weft can improve the finishing effect of the yarn in the flame-retardant finishing agent and does not affect the overall mechanical properties. As can be seen from the results in Comparative Examples 4 and 5, using cellulose nanocrystals as a component of the flame-retardant finishing agent can play its amphiphilic role and improve the penetration of the flame-retardant finishing agent on the yarn. After modification, it can reinforce the fiber and improve the flame-retardant finishing effect.

[0112] Now, the flame-retardant stability of the aramid flame-retardant fabrics prepared in Examples 1-7 and Comparative Examples 1-5 is tested. The samples prepared in different groups are made into samples of 20 cm * 20 cm * 5 cm, and the samples are washed according to the method described in GB / T 17595-1998 "Household laundering procedures before fabric flammability testing", and the changes in the flame-retardant properties (vertical method) of the samples before and after washing are measured to judge the flame-retardant stability of the samples in different groups. The specific test results are shown in Table 2 below.

[0113] Table 2

[0114]

[0115] As can be seen from the results in Table 2, matching a specially designed pattern can improve the stability and flame-retardant effect of the flame-retardant component on the fabric.

[0116] In the description of the specification, the description referring to terms such as "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0117] The above is only an illustration and description of the present invention. Those skilled in the art to which the present technology pertains can make various modifications or supplements to the described specific embodiments or use similar ways to replace them, as long as they do not deviate from the invention or exceed the scope defined by the claims of the present invention, and all should belong to the protection scope of the present invention.

Claims

1. A preparation method of an aramid flame-retardant fabric, characterized in that, It includes the following steps: S1. Fiber pretreatment: The aramid fiber is washed and then treated with an alkali solution to obtain pretreated aramid fiber. S2. Yarn preparation: After mixing the pretreated aramid fiber with antistatic fiber, the warp yarn is spun through the steps of bale opening, carding, drawing, roving, spinning, winding, and twisting. The pretreated aramid fiber is mixed with para-aramid and antistatic fiber, and the weft yarn is spun through the steps of bale opening, carding, drawing, roving, spinning, winding, and twisting. S3. Yarn flame retardant finishing: The warp yarn and the weft yarn are impregnated in a flame retardant finishing solution for padding treatment, taken out with a liquor pickup rate of 65 - 80%, and then heat treated at 70 - 80 °C for 20 - 30 minutes to obtain flame retardant warp yarn and flame retardant weft yarn respectively. S4. Fabric weaving: After determining the fabric structure, the flame retardant warp yarn and the flame retardant weft yarn are used for winding, warping, sizing, and reed threading processes to weave a grey fabric. S5. Fabric post-treatment: The grey fabric obtained in step S4 is subjected to stenter setting, heat setting, and rolling processes to obtain an aramid flame retardant fabric.

2. The preparation method of an aramid flame-retardant fabric according to claim 1, characterized in that, In step S1, the pretreated aramid fiber is specifically prepared by the following steps: S11. The aramid fiber is soaked in absolute ethanol and ultrasonically treated for 2 - 3 hours, filtered with deionized water, and then dried at 90 - 100 °C for standby. S12. The aramid fiber obtained in step S11 is impregnated in an alkaline solution, stirred at 70 - 80 °C and a rate of 30 - 90 rpm for 2 - 3 hours, then filtered, and the filtrate is filtered with deionized water and dried to obtain pretreated aramid fiber.

3. The preparation method of an aramid flame retardant fabric according to claim 2, characterized in that, In step S11, the aramid fiber is meta-aramid.

4. The preparation method of an aramid flame retardant fabric according to claim 2, characterized in that, In step S12, the alkaline solution is a 5 - 20 wt% NaOH solution.

5. The preparation method of an aramid flame-retardant fabric according to claim 1, characterized in that, In step S2, the warp yarn is obtained by blending the pretreated aramid fiber and the antistatic fiber according to a mass ratio of (95 - 98):(2 - 5); the weft yarn is obtained by blending the pretreated aramid fiber, para-aramid, and antistatic fiber according to a mass ratio of (90 - 95):(3 - 7):(2 - 3).

6. The preparation method of an aramid flame-retardant fabric according to claim 1, characterized in that, In step S3, the flame retardant finishing solution is specifically prepared by the following steps: S31. 2-Morpholinoethanesulfonic acid is added to sterile deionized water, and the pH value of the system is adjusted to 5.5 - 6.7 to obtain a 2-morpholinoethanesulfonic acid buffer solution; carboxylated cellulose nanocrystals, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride, N-hydroxysuccinimide, and dopamine hydrochloride are dissolved in the 2-morpholinoethanesulfonic acid buffer solution, and stirred at room temperature and in an inert gas atmosphere for 20 - 30 hours to obtain modified cellulose nanocrystals. S32. The composite flame retardant, modified cellulose nanocrystals, surfactant, and penetrant are mixed in deionized water at 30 - 40 °C at a rate of 30 - 90 rpm for 40 - 60 minutes to obtain the flame retardant finishing solution.

7. The preparation method of an aramid flame-retardant fabric according to claim 6, wherein, In step S32, the composite flame retardant is prepared by compounding decabromodiphenylethane and metal oxide according to a mass ratio of (2.5 - 3.5):

1.

8. The preparation method of an aramid flame-retardant fabric according to claim 1, characterized in that, In step S4, the fabric structure is at least one of a plain weave, a checkerboard weave, a diamond weave, and a honeycomb weave. An aramid flame-retardant fabric prepared by the method for preparing an aramid flame-retardant fabric according to any one of claims 1-8.

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