Flame-retardant nylon yarn and process for its production

Abstract

The application relates to the technical field of nylon, and discloses a flame-retardant nylon yarn and a preparation process thereof. Bis(amino-benzothiazole) phosphate phenyl ester and acetic acid-pentapolyethylene glycol-acetic acid are used for polymerization reaction to obtain a polyamide hydrophilic flame-retardant finishing agent. The nylon yarn is finished, the nylon yarn keeps very low water drop diffusion time and good hydrophilicity, and the hydrophilic and moisture-permeable performance of the nylon yarn is ensured. The polyamide hydrophilic flame-retardant finishing agent can be firmly attached to the surface of the nylon fiber yarn to form a firm hydrophilic polymer film, and the finishing agent is not easy to fall off after water washing. The phosphate ester and the benzothiazole structure in the polyamide hydrophilic flame-retardant finishing agent form a nitrogen-phosphorus-sulfur synergistic flame-retardant system, good flame-retardant effect is achieved, the total heat release amount and the combustion heat release rate peak value of the nylon fiber yarn during combustion are reduced, and excellent flame-retardant performance is shown.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of nylon, in particular to a flame-retardant nylon yarn and a preparation process thereof. BACKGROUND

[0002] Nylon is the earliest synthetic fiber to achieve industrial production in the world, and is widely used. Nylon fiber yarn and fabric have good mechanical strength, wear resistance, high temperature resistance and other properties, and can be made into products such as ropes, packaging woven bags, fire suits, etc. Due to the large crystallinity of nylon fiber, the hydrophilicity and moisture absorption of nylon fiber yarn and fabric are poor, and static electricity is easy to occur, and the wearing comfort of the fabric is not good. Moreover, nylon fiber is flammable, and a large amount of molten droplets will be generated during combustion, which has a great safety hazard.

[0003] In recent years, the development of new finishing agents applied to the field of nylon and other fiber yarns and fabrics is a research hotspot. Among them, polyamide finishing agents have the advantages of good hydrophilicity, diverse preparation processes, etc. Patent CN105542153B discloses a polyamide polyether organic silicon ternary copolymer hydrophilic finishing agent prepared from hexanediamine, adipic acid, double-end carboxyl polyethylene glycol, double-end amino polyether silicone oil and other raw materials, which has good hydrophilic finishing effect on fabric, but the finishing agent does not improve the flame retardance of the fabric. SUMMARY

[0004] The technical problem solved by the present application is to provide a new type of polyamide hydrophilic flame-retardant finishing agent and a nylon yarn with excellent hydrophilicity and flame retardance.

[0005] The technical solution of the present application:

[0006] A preparation process of a flame-retardant nylon yarn, comprising the following steps:

[0007] Step (1): adding di(amino-benzothiazole) phosphate phenyl ester and acetic acid-pentaethylene glycol-acetic acid into a reaction kettle, purging nitrogen, first heating to 190-210 DEG C, reacting for 3-5 h, discharging the reaction kettle to a normal pressure state in the kettle, then heating to 230-245 DEG C, reacting for 2-3 h, cooling, washing the product with ethanol to obtain a polyamide hydrophilic flame-retardant finishing agent.

[0008] Step (2): adding the polyamide hydrophilic flame-retardant finishing agent into water, stirring to obtain a finishing liquid, putting the nylon yarn into the finishing liquid, carrying out double-dipping and double-rolling, taking out the nylon yarn, drying at 80-100 DEG C for 5-10 min, and baking at 165-180 DEG C for 30-60 s to obtain a flame-retardant nylon yarn.

[0009] In step (1), the ratio of di(amino-benzothiazole) phosphate phenyl ester and acetic acid-pentaethylene glycol-acetic acid is (1.9-2.3) mol:1 mol.

[0010] The structural formula of the bis(amino-benzothiazole) phenyl phosphate is:

[0011] The structural formula of the acetic acid-pentaethylene glycol-acetic acid is:

[0012] In step (2), the mass concentration of the finishing liquid is 15-50 g / L.

[0013] The preparation process of the bis(amino-benzothiazole) phenyl phosphate includes the following steps:

[0014] Step (3): adding a reaction solvent, 3-hydroxy-5-nitrobenzaldehyde, and triethylamine into a reaction container, adding phenyl dichlorophosphate under an ice water bath, and then reacting for 5-12 h at room temperature, rotary evaporation, n-hexane washing, dichloromethane recrystallization, to obtain bis(5-nitrobenzaldehyde) phenyl phosphate.

[0015] Step (4): adding dimethyl sulfoxide, bis(5-nitrobenzaldehyde) phenyl phosphate, and 2-aminobenzenethiol into a reaction container, heating to 145-160℃, reacting for 2-4 h, adding water and ethyl acetate after cooling, extracting and separating to collect the organic phase, rotary evaporation, washing the intermediate with n-hexane, then dissolving into ethanol, adding a catalyst and a reducing agent, stirring uniformly, reacting for 12-24 h at room temperature, rotary evaporation, adding water and ethyl acetate after water washing, extracting and separating to collect the organic phase, rotary evaporation, washing the crude product with n-hexane, dichloromethane recrystallization, to obtain bis(amino-benzothiazole) phenyl phosphate.

[0016] In step (3), the reaction solvent is any one of dichloromethane, chloroform, tetrahydrofuran, and acetonitrile.

[0017] In step (3), the proportion of 3-hydroxy-5-nitrobenzaldehyde, triethylamine, and phenyl dichlorophosphate is 2-2.6 mol:(2.2-2.6) mol:1 mol.

[0018] In step (4), the proportion of bis(5-nitrobenzaldehyde) phenyl phosphate and 2-aminobenzenethiol is 1 mol:(2.1-2.4) mol.

[0019] In step (4), the catalyst includes copper sulfate, and the reducing agent includes sodium borohydride.

[0020] The technical effect of the present application is that: the polyamide hydrophilic flame-retardant finishing agent is obtained by carrying out a polymerization reaction on di(amino-benzothiazole) phosphate phenyl ester, acetic acid-pentaethylene glycol-acetic acid, and the main chain of the polyamide hydrophilic flame-retardant finishing agent contains a large number of hydrophilic amide bonds and short-chain polyether bonds, so that the nylon yarn maintains a very low water drop diffusion time and good hydrophilicity, and the hydrophilic and moisture permeability of the nylon yarn is ensured. And the oxygen atoms of the amide bonds and short-chain polyether bonds in the main chain can form hydrogen bond interactions with the amide bonds in the main chain of the nylon molecule, so that the polyamide hydrophilic flame-retardant finishing agent can be firmly attached to the surface of the nylon fiber yarn to form a firm hydrophilic polymer film, and the finishing agent is not easy to fall off after washing, so that the nylon fiber yarn still maintains a low water drop diffusion time and excellent hydrophilicity.

[0021] The phosphate ester and benzothiazole structure in the polyamide hydrophilic flame-retardant finishing agent of the present application form a nitrogen-phosphorus-sulfur synergistic flame-retardant system, which has good flame-retardant effect, reduces the total heat release and the peak value of the heat release rate during the combustion of the nylon fiber yarn, and exhibits excellent flame-retardant performance. And the polyamide hydrophilic flame-retardant finishing agent can be firmly attached to the surface of the nylon fiber yarn to form a firm flame-retardant polymer film, and the finishing agent is not easy to fall off after washing, still maintaining a low total heat release and a low peak value of the heat release rate. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 is a reaction route diagram for preparing di(5-nitrobenzaldehyde) phosphate phenyl ester.

[0023] Figure 2 is a reaction route diagram for preparing di(amino-benzothiazole) phosphate phenyl ester.

[0024] Figure 3 is a reaction mechanism diagram for preparing the polyamide hydrophilic flame-retardant finishing agent. DETAILED DESCRIPTION

[0025] To make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme of the embodiments of the present application will be described clearly and completely below in combination with the drawings of the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the described embodiments of the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of protection of the present application.

[0026] The main raw material of the present application is 3-hydroxy-5-nitrobenzaldehyde, CAS No. 193693-95-7.

[0027] Phenyl dichlorophosphate, CAS No. 770-12-7.

[0028] 2-aminothiophenol, CAS No. 137-07-5.

[0029] Acetic acid-pentaethylene glycol-acetic acid, CAS No. 77855-76-6.

[0030] Example 1

[0031] Into the reaction vessel, acetonitrile solvent, 60 mmol of 3-hydroxy-5-nitrobenzaldehyde, 78 mmol of triethylamine were added, 30 mmol of phenyl dichlorophosphate was added under ice water bath, then reacted at room temperature for 5 h, rotary evaporation, n-hexane washing, dichloromethane recrystallization, to obtain bis(5-nitrobenzaldehyde) phosphate phenyl ester.

[0032] Into the reaction vessel, dimethyl sulfoxide, 40 mmol of bis(5-nitrobenzaldehyde) phosphate phenyl ester, 96 mmol of 2-aminothiophenol were added, and the temperature was raised to 145℃, and reacted for 4 h, then water was added after cooling, ethyl acetate, the organic phase was collected by extraction and separation, rotary evaporation, the intermediate was washed with n-hexane, then dissolved in ethanol, 10 mmol of copper sulfate catalyst and 92 mmol of sodium borohydride reducing agent were added, stirred uniformly, reacted at room temperature for 18 h, rotary evaporation, after water washing, water, ethyl acetate were added, the organic phase was collected by extraction and separation, rotary evaporation, the crude product was washed with n-hexane, dichloromethane recrystallization, to obtain bis(amino-benzothiazole) phosphate phenyl ester.

[0033] Into the reaction vessel, 76 mmol of bis(amino-benzothiazole) phosphate phenyl ester, 40 mmol of acetic acid-pentaethylene glycol-acetic acid were added, nitrogen was introduced, the temperature was raised to 210℃ first, reacted for 3 h, the reaction vessel was vented to normal pressure, then the temperature was raised to 230℃ and reacted for 3 h, cooled, the product was washed with ethanol, to obtain a polyamide hydrophilic flame-retardant finishing agent.

[0034] The polyamide hydrophilic flame-retardant finishing agent was added to water, stirred uniformly to prepare a finishing liquid with a mass concentration of 15 g / L, the nylon yarn was put into the finishing liquid, two-dip-two-roll was carried out, the nylon yarn was taken out, dried at 80℃ for 10 min; baked at 170℃ for 40 s, to obtain a flame-retardant nylon yarn.

[0035] Example 2

[0036] Into the reaction vessel, dichloromethane solvent, 78 mmol of 3-hydroxy-5-nitrobenzaldehyde, 78 mmol of triethylamine were added, 30 mmol of phenyl dichlorophosphate was added under ice water bath, then reacted at room temperature for 5 h, rotary evaporation, n-hexane washing, dichloromethane recrystallization, to obtain bis(5-nitrobenzaldehyde) phosphate phenyl ester.

[0037] Into a reaction vessel was added dimethyl sulfoxide, 40 mmol of bis(5-nitrobenzaldehyde) phenyl phosphate, 84 mmol of 2-aminothiophenol, and the temperature was raised to 150°C for 4 hours. After cooling, water and ethyl acetate were added, the organic phase was collected, and rotary evaporation was performed. The intermediate was washed with n-hexane and then dissolved in ethanol. 9 mmol of copper sulfate as a catalyst and 98 mmol of sodium borohydride as a reducing agent were added, and the mixture was stirred uniformly at room temperature for 24 hours. After washing with water, water and ethyl acetate were added, the organic phase was collected, and rotary evaporation was performed. The crude product was washed with n-hexane and recrystallized with dichloromethane to obtain bis(amino-benzothiazole) phenyl phosphate.

[0038] Into a reaction vessel was added 92 mmol of bis(amino-benzothiazole) phenyl phosphate, 40 mmol of acetic acid-pentaethylene glycol-acetic acid, and nitrogen was introduced. The temperature was raised to 190°C for 5 hours, the reaction vessel was released to atmospheric pressure, and the temperature was raised to 230°C for 3 hours. After cooling, the product was washed with ethanol to obtain a polyamide hydrophilic flame-retardant finishing agent.

[0039] The polyamide hydrophilic flame-retardant finishing agent was added to water to prepare a finishing solution having a mass concentration of 30 g / L. Nylon yarn was dipped into the finishing solution twice and then taken out. The yarn was dried at 100°C for 5 minutes, and then baked at 180°C for 30 seconds to obtain flame-retardant nylon yarn.

[0040] Example 3

[0041] Into a reaction vessel was added tetrahydrofuran solvent, 60 mmol of 3-hydroxy-5-nitrobenzaldehyde, and 66 mmol of triethylamine. Then, 30 mmol of phenyl dichlorophosphate was added under an ice water bath, and the mixture was reacted at room temperature for 12 hours. Rotary evaporation was performed, and the product was washed with n-hexane and recrystallized with dichloromethane to obtain bis(5-nitrobenzaldehyde) phenyl phosphate.

[0042] Into a reaction vessel was added dimethyl sulfoxide, 40 mmol of bis(5-nitrobenzaldehyde) phenyl phosphate, 90 mmol of 2-aminothiophenol, and the temperature was raised to 160°C for 2 hours. After cooling, water and ethyl acetate were added, the organic phase was collected, and rotary evaporation was performed. The intermediate was washed with n-hexane and then dissolved in ethanol. 10 mmol of copper sulfate as a catalyst and 98 mmol of sodium borohydride as a reducing agent were added, and the mixture was stirred uniformly at room temperature for 12 hours. After washing with water, water and ethyl acetate were added, the organic phase was collected, and rotary evaporation was performed. The crude product was washed with n-hexane and recrystallized with dichloromethane to obtain bis(amino-benzothiazole) phenyl phosphate.

[0043] Into a reaction kettle, 82 mmol of bis(amino-benzothiazole) phenyl phosphate, 40 mmol of acetic acid-pentaethylene glycol-acetic acid were added, nitrogen was introduced, and the temperature was first raised to 200°C, and the reaction was carried out for 5 h. The reaction kettle was vented to a normal pressure state, and then the temperature was raised to 245°C and the reaction was carried out for 2 h. After cooling, the product was washed with ethanol to obtain a polyamide hydrophilic flame-retardant finishing agent.

[0044] The polyamide hydrophilic flame-retardant finishing agent was added to water, stirred to obtain a finishing liquid with a mass concentration of 50 g / L, and then the nylon yarn was placed in the finishing liquid for two-dip-two-roll. The nylon yarn was taken out, dried at 90°C for 5 min, and then baked at 165°C for 60 s to obtain a flame-retardant nylon yarn.

[0045] The difference between Comparative Example 1 and Example 1 is that:

[0046] Bis(5-nitrobenzaldehyde) phenyl phosphate was added to water, stirred to obtain a finishing liquid with a mass concentration of 15 g / L, and then the nylon yarn was placed in the finishing liquid for two-dip-two-roll. The nylon yarn was taken out, dried at 80°C for 10 min, and then baked at 170°C for 40 s to obtain a nylon yarn.

[0047] The difference between Comparative Example 2 and Example 1 is that:

[0048] Bis(amino-benzothiazole) phenyl phosphate was added to water, stirred to obtain a finishing liquid with a mass concentration of 15 g / L, and then the nylon yarn was placed in the finishing liquid for two-dip-two-roll. The nylon yarn was taken out, dried at 80°C for 10 min, and then baked at 170°C for 40 s to obtain a nylon yarn.

[0049] The difference between Comparative Example 3 and Example 1 is that:

[0050] Acetic acid-pentaethylene glycol-acetic acid was added to water, stirred to obtain a finishing liquid with a mass concentration of 15 g / L, and then the nylon yarn was placed in the finishing liquid for two-dip-two-roll. The nylon yarn was taken out, dried at 80°C for 10 min, and then baked at 170°C for 40 s to obtain a nylon yarn.

[0051] The nylon yarn was tested according to the method of AATCC 79-2014. The shorter the water absorption diffusion time, the better the hydrophilicity.

[0052] The nylon yarn was washed 10 times according to the method of GB / T 8629-2001, and then the water absorption diffusion time and hydrophilicity of the nylon yarn were tested.

[0053]

[0054] Examples 1 to 3 are polymerized with bis(amino-benzothiazole) phenyl phosphate, acetic acid-pentaethylene glycol-acetic acid to obtain polyamide hydrophilic flame-retardant finishing agent. The main chain of the polyamide hydrophilic flame-retardant finishing agent contains a large number of hydrophilic amide bonds and short-chain polyether bonds, so that the nylon yarn maintains a very low water drop spreading time and good hydrophilicity, ensuring the hydrophilic and moisture permeability of the nylon yarn. And the oxygen atoms of the amide bond and the short-chain polyether bond in the main chain can form hydrogen bond interaction with the amide bond in the main chain of the nylon molecule, so that the polyamide hydrophilic flame-retardant finishing agent can be firmly attached to the surface of the nylon fiber yarn to form a firm hydrophilic polymer film. After washing, the finishing agent is not easy to fall off, so that the nylon fiber yarn still maintains a low water drop spreading time and excellent hydrophilicity. Among them, examples 1 and 2 have lower increase in total heat release and peak value of heat release rate of combustion than example 3 after washing.

[0055] Comparative examples 1 and 2 respectively use aqueous solutions of bis(5-nitrobenzaldehyde) phenyl phosphate and bis(amino-benzothiazole) phenyl phosphate as finishing liquids. Both of them are hydrophobic small molecules with poor water solubility, and cannot form a uniform and stable finishing liquid. The hydrophilic finishing effect on nylon fiber yarn is poor, and the water drop spreading time of the finished nylon yarn is large and the hydrophilicity is very poor. However, the water drop spreading time of the washed nylon yarn is decreased, because the compatibility and interfacial force between bis(5-nitrobenzaldehyde) phenyl phosphate and bis(amino-benzothiazole) phenyl phosphate and nylon yarn are low, and a firm polymer film cannot be formed on the surface of the nylon yarn. After washing, the hydrophobic finishing agent is easy to fall off, thereby reducing the water drop spreading time of the nylon yarn.

[0056] The flame-retardant properties of the nylon yarn before and after washing for 10 times were tested by a micro calorimeter, and the radiation intensity was 35 kW / m 2 .

[0057]

[0058] Embodiments 1 to 3 use bis(amino-benzothiazole) phosphate phenyl ester as a functional monomer, and obtain a polyamide hydrophilic flame-retardant finishing agent containing phosphate and benzothiazole structures through a polymerization reaction. The polyamide hydrophilic flame-retardant finishing agent is used to finish nylon yarn. The phosphate and benzothiazole structures in the polyamide hydrophilic flame-retardant finishing agent form a nitrogen-phosphorus-sulfur synergistic flame-retardant system, which has a good flame-retardant effect, reduces the total heat release and the peak heat release rate of the nylon fiber yarn during combustion, and exhibits excellent flame-retardant performance. In addition, the oxygen atoms of the amide bond and the short-chain polyether bond in the main chain of the polyamide hydrophilic flame-retardant finishing agent can form hydrogen bond interactions with the amide bond in the main chain of the nylon molecule, so that the polyamide hydrophilic flame-retardant finishing agent can be firmly attached to the surface of the nylon fiber yarn to form a firm flame-retardant polymer film. After washing, the finishing agent is not easy to fall off, and still maintains a low total heat release and a low peak heat release rate.

[0059] Comparative Examples 1 and 2 use aqueous solutions of bis(5-nitrobenzaldehyde) phosphate phenyl ester and bis(amino-benzothiazole) phosphate phenyl ester as flame retardant finishing liquids, respectively. The finishing effect on nylon fiber yarn is poor, and a firm flame-retardant polymer film cannot be formed on the surface of the nylon yarn. Therefore, the total heat release and the peak heat release rate during combustion before washing are large, and the flame retardant easily falls off after washing, which increases the total heat release and the peak heat release rate during combustion.

[0060] The total heat release and the peak heat release rate of Comparative Example 2 are lower than those of Comparative Example 1, because the bis(amino-benzothiazole) phosphate phenyl ester in Comparative Example 2 contains phosphate and benzothiazole structures that form a nitrogen-phosphorus-sulfur synergistic flame-retardant system, so the flame-retardant effect is better than that of Comparative Example 1. Comparative Example 3 uses acetic acid-pentaethylene glycol-acetic acid to finish nylon fiber yarn, and has the worst flame-retardant performance.

Claims

1. A process for the preparation of flame retardant nylon yarns, characterized in that, It comprises the following steps: Step (1): adding di (amino-benzothiazole) phosphate phenyl ester, PEG6- (CH2COOH) 2 into a reaction kettle, purging nitrogen, first heating to 190-210 DEG C, reacting for 3-5h, releasing the reaction kettle to the normal pressure state in the kettle, then heating to 230-245 DEG C, reacting for 2-3h, cooling, washing, obtaining polyamide hydrophilic flame-retardant finishing agent; Step (2): adding the polyamide hydrophilic flame-retardant finishing agent into water, stirring to be uniform, configuring into finishing liquid, putting nylon yarn into the finishing liquid, carrying out two-dip-two-roll, taking out the nylon yarn, drying at 80-100 DEG C for 5-10min, baking at 165-180 DEG C for 30-60s, obtaining flame-retardant nylon yarn; The ratio of di (amino-benzothiazole) phosphate phenyl ester and acetic acid-pentapolyethylene glycol-acetic acid in step (1) is (1.9-2.3) mol:1 mol; The bis(amino-benzothiazole) phosphoric acid phenyl ester has the structural formula: ; The acetic acid-pentapolyethylene glycol-acetic acid has the structural formula of: ; The preparation process of the di (amino-benzothiazole) phosphate phenyl ester comprises the following steps: Step (3): adding reaction solvent, 3-hydroxy-5-nitrobenzaldehyde, triethylamine into a reaction container, then adding phenyl dichlorophosphate under ice water bath, then reacting for 5-12h at room temperature, rotary evaporation, washing, recrystallization, obtaining di (5-nitrobenzaldehyde) phosphate phenyl ester; Step (4): adding dimethyl sulfoxide, di (5-nitrobenzaldehyde) phosphate phenyl ester, 2-aminobenzenethiol into a reaction container, heating to 145-160 DEG C, reacting for 2-4h, extracting and separating after cooling, dissolving the intermediate into ethanol after washing, adding catalyst, reducing agent, stirring uniformly, reacting for 12-24h at room temperature, rotary evaporation, extracting and separating after washing, recrystallization, obtaining di (amino-benzothiazole) phosphate phenyl ester.

2. The process for the preparation of flame retardant nylon yarn as claimed in claim 1 wherein, The mass concentration of the finishing liquid in step (2) is 15-50g / L.

3. The process for the preparation of flame retardant nylon yarn as claimed in claim 1 wherein, The reaction solvent in step (3) is any one of dichloromethane, chloroform, tetrahydrofuran, acetonitrile.

4. The process for preparing flame retardant nylon yarn as claimed in claim 1 wherein, The ratio of 3-hydroxy-5-nitrobenzaldehyde, triethylamine, phenyl dichlorophosphate in step (3) is 2-2.6mol: (2.2-2.6) mol:1 mol.

5. The process for preparing flame retardant nylon yarn as claimed in claim 1 wherein, The ratio of di (5-nitrobenzaldehyde) phosphate phenyl ester and 2-aminobenzenethiol in step (4) is 1 mol: (2.1-2.4) mol.

6. The process for preparing flame retardant nylon yarn as claimed in claim 1 wherein, The catalyst in step (4) comprises copper sulfate, and the reducing agent comprises sodium borohydride.

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