Preparation method of flame-retardant fiber for fabric

Abstract

The invention relates to the technical field of fibers, and discloses a preparation method of flame-retardant fibers for fabrics, which comprises the following steps: adding polyurethane resin and a hydroxyl polyamide flame retardant into N, N-dimethylformamide, stirring to prepare a spinning solution, and spinning through an electrostatic spinning machine to obtain the flame-retardant fibers for fabrics. The hydroxyl polyamide flame retardant contains a large number of hydrophilic hydroxyl groups, the moisture regain and the moisture absorption performance of the fiber are improved, the flame retardant and polyurethane resin have similar compatibility, meanwhile, the hydroxyl groups contained in the flame retardant and the polyurethane resin can generate hydrogen-bond interaction, the interfacial interaction force between the hydroxyl groups and the polyurethane resin is improved, and the flame-retardant performance of the fiber is improved. The flame retardant can be uniformly dispersed in a spandex fiber matrix, and the fiber still keeps good mechanical properties. The spandex fiber disclosed by the invention can be blended with cotton fiber, wool and the like to prepare a fabric and a textile which are high in flame retardance, good in mechanical property, hydrophilic and moisture-absorbing.

Description

Technical Field

[0001] The invention relates to the technical field of fibers, and in particular to a method for preparing flame-retardant fibers for fabrics. Background Art

[0002] Spandex fiber is a synthetic fiber obtained by spinning polyurethane resin, which has good elasticity, strength and hydrophilic hygroscopicity. It can be blended with cotton fiber, wool fiber, polyester fiber, etc. to obtain fiber and fabric products with excellent performance. However, spandex fiber is easy to burn and has poor flame retardant performance, which hinders its practical application in fireproof fabric textiles and the like. Adding flame retardants to spandex fiber can improve its flame retardant performance, such as nitrogen flame retardants, phosphorus flame retardants, bromine flame retardants, etc. The patent with publication number CN119101210A discloses a high-performance flame-retardant spandex fiber and a preparation method thereof. Phosphorus-containing dihydroxy compounds, nitrogen-containing dihydroxy compounds, catalysts, polar amines and prepolymers are polymerized, and then spun after ripening to obtain high-performance flame-retardant spandex yarn, which gives spandex excellent flame retardant performance, mechanical properties and controllable elasticity. Compared with high-performance flame-retardant spandex fiber, the spandex fiber of the present invention has better moisture regain and hygroscopicity. Summary of the invention

[0003] The invention solves the problem of poor flame retardancy of spandex fibers and improves the hydrophilicity of the spandex fibers.

[0004] Technical solution: A method for preparing flame-retardant fiber for fabrics:

[0005] Step A: add triethylamine, 5-methoxyisophthalamidoethylenediamine and phenyl dichlorophosphate to acetonitrile in an ice-water bath, remove the ice-water bath, stir and react at 20-25° C. for 18-24 hours, filter, wash with water and acetone in turn, and dry to obtain a methoxy polyamide flame retardant.

[0006] Step B: Add methoxy polyamide flame retardant to dichloromethane in an ice water bath, stir and then add dichloromethane solution of boron tribromide, stir and react at 0-5°C for 6-12h, rotary evaporate, wash with water and ethanol in turn, and dry to obtain hydroxy polyamide flame retardant. The reaction formula is:

[0007]

[0008] Step C: adding polyurethane resin and hydroxy polyamide flame retardant to N,N-dimethylformamide, stirring to prepare spinning solution, spinning through an electrostatic spinning machine to obtain flame retardant fiber for fabric.

[0009] Preferably, in step A, the amount of phenyl dichlorophosphate is 100 parts by weight, the amount of triethylamine is 96-105 parts by weight, and the amount of 5-methoxyisophthalamidoethylenediamine is 133-146 parts by weight.

[0010] Preferably, the preparation method of 5-methoxyisophthalamide ethylenediamine is as follows: add 100 parts by weight of 5-methoxyisophthalic acid, 163-180 parts by weight of N-tert-butyloxycarbonyl-1,2-ethylenediamine, 165-193 parts by weight of 1-hydroxybenzotriazole (HOBt), and 234-273 parts by weight of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDCl) to dichloromethane, stir at 20-30°C for amidation reaction for 18-24h, rotary evaporate, wash the product with water and petroleum ether, then add it to a dichloromethane solution of trifluoroacetic acid, stir at 20-30°C for reaction for 3-5h, remove the Boc protecting group, rotary evaporate, purify by silica gel column chromatography, and the eluent is a mixture of ethyl acetate and petroleum ether to obtain 5-methoxyisophthalamide ethylenediamine. The reaction formula is:

[0011]

[0012] Preferably, in step B, the amount of methoxy polyamide flame retardant used is 100 parts by weight, and the amount of boron tribromide used is 80-110 parts by weight.

[0013] Preferably, in step B, the amount of the polyurethane resin used is 100 parts by weight, and the amount of the hydroxy polyamide flame retardant is 5-15 parts by weight.

[0014] Preferably, the voltage during spinning in step B is 16-20 kV, the spinning solution flow rate is 10-15 mL / h, and the receiving distance is 20-25 cm.

[0015] (III) Beneficial technical effects: The present invention polycondenses 5-methoxyisophthalamide ethylenediamine and phenyl dichlorophosphate, then removes the methyl group by boron tribromide to obtain a hydroxy polyamide flame retardant, which is then electrostatically spun by blending with a polyurethane resin to obtain a flame retardant fiber for fabrics. The hydroxy polyamide flame retardant contains a phosphoramide structure to form a nitrogen-phosphorus flame retardant system, which has a good condensed phase flame retardant effect, significantly reduces the peak heat release rate and total heat release of the fiber, and exhibits good flame retardant properties.

[0016] The hydroxy polyamide flame retardant of the present invention contains a large number of hydrophilic hydroxyl groups, which is beneficial to improving the moisture regain and hygroscopicity of the fiber, and the flame retardant molecule main chain contains an amide bond structural unit, and the carbamate group in the polyurethane resin molecular chain also contains an amide bond, so the two have similar compatibility, and the hydroxyl groups contained in the flame retardant can hydrogen bond with the polyurethane resin to improve the interface interaction between the two, so that the flame retardant can be evenly dispersed in the spandex fiber matrix, and the fiber still maintains good mechanical properties. The spandex fiber of the present invention can be blended with cotton fiber, wool, etc. to make fabrics and textiles with high flame retardancy, good mechanical properties, and hydrophilic and hygroscopic properties. DETAILED DESCRIPTION

[0017] Polyurethane resin of the present invention

[0018] The technical solutions in the embodiments of the present application are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present application.

[0019] Example 1: (1) Add 1 g of 5-methoxyisophthalic acid, 1.8 g of N-tert-butyloxycarbonyl-1,2-ethylenediamine, 1.93 g of 1-hydroxybenzotriazole, and 2.73 g of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride to 40 mL of dichloromethane, stir and react at 20° C. for 18 h, and evaporate by rotary evaporation. The product is washed with water and petroleum ether, and then added to a solution of trifluoroacetic acid (6 mL) in dichloromethane (10 mL). Stir and react at 30° C. for 3 h, and evaporate by rotary evaporation. Purify by silica gel column chromatography, using a mixture of ethyl acetate and petroleum ether as the eluent to obtain 5-methoxyisophthalamide ethylenediamine.

[0020] (2) In an ice-water bath, add 1.92 g of triethylamine, 2.66 g of 5-methoxyisophthalamidoethylenediamine, and 2 g of phenyl dichlorophosphate to 15 mL of acetonitrile, remove the ice-water bath, stir and react at 20° C. for 18 h, filter, wash with water and acetone in sequence, and dry to obtain a methoxy polyamide flame retardant.

[0021] (3) In an ice water bath, add 5 g of methoxy polyamide flame retardant to 120 mL of dichloromethane, stir, then add 50 mL of dichloromethane solution containing 4 g of boron tribromide, stir and react at 0°C for 12 h, rotary evaporate, wash with water and ethanol in turn, and dry to obtain a hydroxy polyamide flame retardant.

[0022] (4) Add 100 g of polyurethane resin and 5 g of hydroxy polyamide flame retardant to 700 mL of N,N-dimethylformamide, stir to prepare spinning solution, and spin through an electrospinning machine with a control voltage of 18 kV, a spinning solution flow rate of 10 mL / h, and a receiving distance of 25 cm to obtain flame retardant fiber for fabric.

[0023] Example 2: (1) To 40 mL of dichloromethane were added 1 g of 5-methoxyisophthalic acid, 1.63 g of N-tert-butyloxycarbonyl-1,2-ethylenediamine, 1.65 g of 1-hydroxybenzotriazole, and 2.34 g of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride, and the mixture was stirred at 30° C. for 24 h, and the mixture was rotary evaporated. The product was washed with water and petroleum ether, and then added to a solution of trifluoroacetic acid (8 mL) in dichloromethane (15 mL), and the mixture was stirred at 20° C. for 5 h, and rotary evaporated. The mixture was purified by silica gel column chromatography, and the eluent was a mixture of ethyl acetate and petroleum ether to obtain 5-methoxyisophthalamidoethylenediamine.

[0024] (2) In an ice-water bath, add 2.03 g of triethylamine, 2.66 g of 5-methoxyisophthalamidoethylenediamine, and 2 g of phenyl dichlorophosphate to 20 mL of acetonitrile, remove the ice-water bath, stir and react at 20° C. for 24 h, filter, wash with water and acetone in sequence, and dry to obtain a methoxy polyamide flame retardant.

[0025] (3) In an ice water bath, add 5 g of methoxy polyamide flame retardant to 150 mL of dichloromethane, stir, then add 50 mL of dichloromethane solution containing 4.8 g of boron tribromide, stir and react at 5°C for 12 h, rotary evaporate, wash with water and ethanol in turn, and dry to obtain a hydroxy polyamide flame retardant.

[0026] (4) Add 100 g of polyurethane resin and 8 g of hydroxy polyamide flame retardant to 750 mL of N,N-dimethylformamide, stir to prepare spinning solution, and spin through an electrospinning machine with a control voltage of 20 kV, a spinning solution flow rate of 10 mL / h, and a receiving distance of 25 cm to obtain flame retardant fiber for fabric.

[0027] Example 3: (1) In an ice-water bath, add 2.1 g of triethylamine, 2.92 g of 5-methoxyisophthalamidoethylenediamine (prepared according to the method of Example 1) and 2 g of phenyl dichlorophosphate to 20 mL of acetonitrile, remove the ice-water bath, stir the reaction at 25°C for 18 h, filter, wash with water and acetone in turn, and dry to obtain a methoxy polyamide flame retardant.

[0028] (2) In an ice water bath, add 5 g of methoxy polyamide flame retardant to 150 mL of dichloromethane, stir, then add 50 mL of dichloromethane solution containing 4 g of boron tribromide, stir and react at 5°C for 12 h, rotary evaporate, wash with water and ethanol in turn, and dry to obtain a hydroxy polyamide flame retardant.

[0029] (3) Add 100 g of polyurethane resin and 12 g of hydroxy polyamide flame retardant to 800 mL of N,N-dimethylformamide, stir to prepare spinning solution, and spin through an electrospinning machine with a control voltage of 16 kV, a spinning solution flow rate of 15 mL / h, and a receiving distance of 25 cm to obtain flame retardant fiber for fabric.

[0030] Example 4: (1) In an ice-water bath, 1.92 g of triethylamine, 2.73 g of 5-methoxyisophthalamidoethylenediamine (prepared according to the method of Example 1) and 2 g of phenyl dichlorophosphate were added to 20 mL of acetonitrile, the ice-water bath was removed, and the reaction was stirred at 25°C for 18 h. The mixture was filtered, washed with water and acetone in turn, and dried to obtain a methoxy polyamide flame retardant.

[0031] (2) In an ice water bath, add 5 g of methoxy polyamide flame retardant to 150 mL of dichloromethane, stir, then add 50 mL of dichloromethane solution containing 5.5 g of boron tribromide, stir and react at 5°C for 6 h, rotary evaporate, wash with water and ethanol in turn, and dry to obtain a hydroxy polyamide flame retardant.

[0032] (3) Add 100 g of polyurethane resin and 15 g of hydroxy polyamide flame retardant to 800 mL of N,N-dimethylformamide, stir to prepare spinning solution, and spin through an electrospinning machine with a control voltage of 18 kV, a spinning solution flow rate of 13 mL / h, and a receiving distance of 20 cm to obtain flame retardant fiber for fabric.

[0033] Comparative Example 1: The difference between this comparative example and Example 1 is that no hydroxy polyamide flame retardant is added.

[0034] (1) Add 100 g of polyurethane resin to 700 mL of N,N-dimethylformamide and stir to prepare a spinning solution, which is then spun by an electrospinning machine at a controlled voltage of 18 kV, a spinning solution flow rate of 10 mL / h, and a receiving distance of 25 cm to obtain a fiber for fabric.

[0035] Comparative Example 2: The difference between this comparative example and Example 1 is that methoxy polyamide flame retardant is used instead of hydroxy polyamide flame retardant.

[0036] (1) Add 100 g of polyurethane resin and 5 g of methoxy polyamide flame retardant to 700 mL of N,N-dimethylformamide, stir to prepare spinning solution, and spin through an electrospinning machine with a control voltage of 18 kV, a spinning solution flow rate of 10 mL / h, and a receiving distance of 25 cm to obtain flame retardant fiber for fabric.

[0037] Comparative Example 3: The difference between this comparative example and Example 1 is that when preparing the flame retardant, ethylenediamine in an equal amount is used instead of 5-methoxyisophthalamideethylenediamine.

[0038] (1) In an ice-water bath, add 2.03 g of triethylamine, 0.57 g of ethylenediamine, and 2 g of phenyl dichlorophosphate to 20 mL of acetonitrile, remove the ice-water bath, stir and react at 20° C. for 24 h, filter, wash with water and acetone in sequence, and dry to obtain a flame retardant.

[0039] (2) Add 100 g of polyurethane resin and 5 g of flame retardant to 700 mL of N,N-dimethylformamide, stir to prepare spinning solution, and spin through an electrospinning machine with a control voltage of 18 kV, a spinning solution flow rate of 10 mL / h, and a receiving distance of 25 cm to obtain flame retardant fiber for fabric.

[0040] The moisture regain of the fiber is tested according to GB / T 9995-1997 standard.

[0041] The tensile properties are tested according to GB / T 14337-2022 standard.

[0042] The combustion performance was tested by cone calorimeter with a thermal radiation condition of 35kW / m 2 .

[0043] Table 1 Fiber performance test

[0044]

[0045] The spandex fiber used in the fabric of Comparative Example 1 has high regain, breaking strength, and breaking elongation, and good hygroscopicity and mechanical properties, but has large peak heat release rate and total heat release, and poor flame retardant properties.

[0046] Hydroxyl polyamide flame retardant is added to the spandex fiber for fabrics of Examples 1-4, which contains a large number of hydrophilic hydroxyl groups, which is beneficial to improving the moisture regain and hygroscopicity of the fiber, and contains a phosphoramide structure to form a nitrogen-phosphorus flame retardant system, which has a good condensed phase flame retardant effect, significantly reduces the peak heat release rate and total heat release of the fiber, and shows good flame retardant performance. Compared with Comparative Example 1, the fibers of Examples 1-4 still maintain good breaking strength and breaking elongation, mainly because the main chain of the flame retardant molecule contains an amide bond structural unit, and the carbamate group in the polyurethane resin molecular chain also contains an amide bond, and the two have similar compatibility. At the same time, the hydroxyl contained in the flame retardant can hydrogen bond with the polyurethane resin, thereby improving the interfacial interaction between the two, so that the flame retardant can be evenly dispersed in the spandex fiber matrix to avoid affecting the mechanical properties of the fiber.

[0047] The methoxy polyamide flame retardant added in Comparative Example 2 does not contain hydrophilic hydroxyl groups, and adding it to the fiber will reduce its moisture regain and hygroscopic properties. The flame retardant contains amide bond structural units in the main chain of the molecule, has good compatibility with the polyurethane resin, has little effect on the mechanical properties of the fiber, and still maintains good breaking strength and breaking elongation.

[0048] Comparative Example 3 uses ethylenediamine and phenyl dichlorophosphate to carry out a condensation reaction to obtain a flame retardant containing a phosphoramide nitrogen-phosphorus flame retardant system, which can significantly reduce the peak heat release rate and total heat release of the fiber and improve the flame retardant properties. However, it does not contain an amide group or a hydroxyl group, and has poor compatibility with the polyurethane resin. It has a great influence on the mechanical properties and hydrophilic hygroscopic properties of the fiber, and the breaking strength, elongation at break and regain are significantly reduced.

Claims

1. A method for preparing flame-retardant fiber for fabric, characterized in that: The preparation method is: Step A, adding triethylamine, 5-methoxyisophthalamidoethylenediamine and phenyl dichlorophosphate to acetonitrile in an ice water bath, stirring to react, filtering, washing and drying to obtain a methoxy polyamide flame retardant; Step B, adding a methoxy polyamide flame retardant to dichloromethane in an ice water bath, adding a dichloromethane solution of boron tribromide after stirring, stirring for reaction, rotary evaporation, washing, and drying to obtain a hydroxy polyamide flame retardant; Step C: adding polyurethane resin and hydroxy polyamide flame retardant to N,N-dimethylformamide, stirring to prepare spinning solution, spinning through an electrostatic spinning machine to obtain flame retardant fiber for fabric.

2. The method for preparing flame-retardant fiber for fabric according to claim 1, characterized in that: The reaction temperature in step A is 20-25° C. and the reaction time is 18-24 h.

3. The method for preparing flame-retardant fiber for fabric according to claim 1, characterized in that: In the step A, the amount of phenyl dichlorophosphate used is 100 parts by weight, the amount of triethylamine used is 96-105 parts by weight, and the amount of 5-methoxyisophthalamidoethylenediamine used is 133-146 parts by weight.

4. The method for preparing flame-retardant fiber for fabric according to claim 3, characterized in that: The preparation method of the 5-methoxyisophthalic acid amidoethylenediamine is as follows: 100 parts by weight of 5-methoxyisophthalic acid, 163-180 parts by weight of N-tert-butyloxycarbonyl-1,2-ethylenediamine, 165-193 parts by weight of 1-hydroxybenzotriazole, and 234-273 parts by weight of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride are added to dichloromethane, stirred for reaction at 20-30° C. for 18-24 hours, rotary evaporated, washed, and then added to a dichloromethane solution of trifluoroacetic acid, stirred for reaction at 20-30° C. for 3-5 hours, rotary evaporated, and purified by silica gel column chromatography to obtain 5-methoxyisophthalic acid amidoethylenediamine.

5. The method for preparing flame-retardant fiber for fabric according to claim 1, characterized in that: In the step B, the amount of the methoxy polyamide flame retardant is 100 parts by weight, and the amount of boron tribromide is 80-110 parts by weight.

6. The method for preparing flame-retardant fiber for fabric according to claim 1, characterized in that: The reaction temperature in step B is 0-5°C and the reaction time is 6-12h.

7. The method for preparing flame-retardant fiber for fabric according to claim 1, characterized in that: In the step B, the amount of the polyurethane resin is 100 parts by weight, and the amount of the hydroxy polyamide flame retardant is 5-15 parts by weight.

8. The method for preparing flame-retardant fiber for fabric according to claim 1, characterized in that: The voltage during spinning in step B is 16-20 kV, the spinning solution flow rate is 10-15 mL / h, and the receiving distance is 20-25 cm.

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