Flame retardant, flame retardant nylon fabric, method of preparation and use thereof

Abstract

The application provides a flame retardant, a flame-retardant nylon fabric, a preparation method and application thereof, and belongs to the technical field of flame retardants. The flame retardant comprises the following components: alkyl phosphate, sulfur / nitrogen-based compound, melamine and solvent; the alkyl phosphate is aliphatic or aromatic containing 1-18 carbon atoms; the ester group in the alkyl phosphate is a mono- or poly-ester containing 1-12 carbon atoms; the sulfur / nitrogen-based compound is a compound containing sulfonic acid group and amino group simultaneously. The flame retardant prepared by the application is used for impregnation treatment of nylon fabric. With the help of phosphate groups, sulfonic acid groups and amino groups in the flame retardant, in the combustion process, a non-volatile phosphoric acid layer is generated to cover the surface of the fabric to isolate oxygen, and a large amount of non-combustible gas is generated to reduce the oxygen concentration, thereby hindering the combustion of the fabric. The prepared flame-retardant nylon fabric has a limiting oxygen index of 35.1-42.4%, reaches the non-combustible standard, has excellent flame-retardant performance, and the melt dripping phenomenon is obviously improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of flame retardants, and more particularly relates to a flame retardant, a flame-retardant nylon fabric, a preparation method and application thereof. BACKGROUND

[0002] Nylon is the first synthetic fiber in the world, and is a kind of polyamide fiber (polyamide). Its appearance is a new look of textiles, and its synthesis is a major breakthrough in the synthetic fiber industry. Nylon fabric has good wear resistance, high breaking strength and good processability, and is widely used in transportation, electronics and electrical appliances, military textiles, aerospace, home decoration and other fields. However, synthetic fibers are highly flammable and cannot meet the fireproof requirements of related textile industries. In addition, molten droplets are generated during combustion, which can ignite other combustible materials and cause secondary fires, resulting in serious consequences. Therefore, it is of great significance to improve the flame retardant performance of nylon fabric and inhibit the dripping phenomenon.

[0003] Flame retardants can be mainly divided into halogen-based flame retardants, silicon-based flame retardants, phosphorus-based flame retardants, nitrogen-based flame retardants, intumescent flame retardants and the like. Halogen-based flame retardants produce toxic substances and do not meet the green and environmentally friendly development concept, and have been banned. The flame-retardant effect of silicon-based flame retardants is poor, and they can affect the softness of the fabric, so they are often used in combination with phosphorus-based flame retardants and nitrogen-based flame retardants. Phosphorus-based flame retardants are widely used in various fabrics due to their high flame retardancy, but they have poor thermal stability and are prone to volatilization.

[0004] The main way to improve phosphorus-based flame retardants at present is to use nitrogen-phosphorus-based flame retardants in combination to achieve phosphorus-nitrogen flame retardants with flame-retardant synergistic effect. For example, Chinese patent CN103898744A discloses a preparation method of halogen-free flame-retardant non-melting nylon 66 fabric. First, the fabric is pretreated, and then the nitrogen-phosphorus flame retardant containing PNF, AS and HEDP is combined with the fabric through sufficient impregnation, conventional impregnation process and baking, so as to achieve the purpose of flame retardation and anti-melt dripping. The oxygen index value of the treated polyamide sample is increased from 21.1% to 26.0%. The flame-retardant effect of the nylon 66 fabric in the patent still needs to be further improved. SUMMARY

[0005] The application aims to provide a flame retardant, a flame-retardant nylon fabric, a preparation method and application thereof. The flame retardant provided by the application has a simple preparation process and good flame-retardant effect on the flame-retardant nylon fabric.

[0006] To achieve the above-mentioned purpose, the first aspect of the application provides a flame retardant comprising the following components: alkyl phosphate, sulfur / nitrogen-based compound, melamine and solvent.

[0007] The alkyl phosphate ester is an aliphatic or aromatic compound containing 1-18 carbon atoms, and the ester group in the alkyl phosphate ester is a mono- or poly-ester containing 1-12 carbon atoms.

[0008] The sulfur / nitrogen-based compound is a compound containing both sulfonic acid group and amino group.

[0009] Further, the alkyl phosphate ester is one or more of dodecyl diethyl phosphate, naphthyl didecyl phosphate, cyclohexane diheptyl phosphate, ethyl diethyl phosphate, propyl diethyl phosphate, dimethyl methylphosphonate, diethyl methylphosphonate, dimethyl phosphate, and diethyl phosphate.

[0010] Further, the sulfur / nitrogen-based compound is one or more of guanidine sulfamate, ammonium sulfamate, sulfamic acid, thiourea, ammonium sulfate, and sulfonamide.

[0011] Further, the molar concentration of the alkyl phosphate ester is 0.8-1.5 mol / L, the molar concentration of the sulfur / nitrogen-based compound is 0.6-1.0 mol / L, and the concentration of the melamine is 3-10 g / L. If the concentration of each component is too low, the flame retardation performance is poor, and if the concentration is too high, the fabric becomes hard, affecting the mechanical properties of the fabric.

[0012] In a second aspect of the present application, a preparation method of a flame retardant is provided, including the following steps: dissolving a sulfur / nitrogen-based compound and melamine in a solvent, adding an alkyl phosphate ester after complete dissolution, stirring uniformly to form a mixture system.

[0013] In a third aspect of the present application, the flame retardant is applied in the preparation of a flame-retardant fabric.

[0014] In a fourth aspect of the present application, a flame-retardant nylon fabric is provided, which is prepared by the following method: pretreating a nylon fabric; immersing the pretreated nylon fabric in the above-mentioned flame retardant for treatment, and drying and curing after immersion to obtain a durable flame-retardant nylon fabric.

[0015] Further, the process of immersing the pretreated nylon fabric in the above-mentioned flame retardant for treatment is carried out in steps: first immersing the pretreated nylon fabric in a system containing a sulfur / nitrogen-based compound and melamine, drying after the first immersion; then immersing the nylon fabric after the first immersion treatment in a system containing an alkyl phosphate ester, and curing after the second immersion.

[0016] Further, the drying treatment is drying at 80°C for 10-20 min, and the curing treatment is drying at 180°C for 5-10 min.

[0017] Further, the pretreatment is to immerse the nylon fabric in a sodium hydroxide or sodium carbonate solution with a concentration of 1-5 wt% for 20-24 h, then wash to near neutral with water, and dry at 70-80℃.

[0018] Further, the nylon fabric is polyamide 6 or polyamide 66.

[0019] Further, the first immersion time is 1-5 h, and the second immersion time is 5-10 min.

[0020] Compared with the prior art, the application has the following technical effects:

[0021] The flame retardant of the application uses alkyl phosphate, melamine and sulfur / nitrogen-based compounds as raw materials, and a new phosphorus / nitrogen / sulfur flame retardant is prepared by compounding.

[0022] The flame retardant prepared by the application is used to impregnate the nylon fabric. In the combustion process, the phosphate groups on the surface of the fabric decompose under heat to form a non-volatile phosphoric acid layer covering the surface of the fabric, thereby insulating oxygen and heat transfer, playing a shielding role, and achieving condensed phase flame retardation. At the same time, the amino groups decompose under heat to produce a large amount of non-combustible gas, reducing the oxygen concentration and hindering the combustion of the fabric, thereby achieving gas phase flame retardation. The sulfonic acid groups decompose under heat to produce sulfur dioxide, which captures active free radicals, inhibits the combustion chain reaction, and generates non-combustible gas, thereby diluting oxygen and combustible gas to play a flame-retardant effect, mainly playing a gas phase flame-retardant mechanism.

[0023] The flame retardant prepared by the application mainly acts on the nylon fabric through condensed phase flame retardation and gas phase flame retardation to achieve flame retardation. The prepared flame-retardant nylon fabric has a limiting oxygen index of 35.1-42.4%, reaching the non-combustible standard, has excellent flame-retardant performance, and the melt dripping phenomenon is significantly improved.

[0024] The preparation process of the flame retardant and the flame-retardant nylon fabric of the application is simple and can be mass-produced. DETAILED DESCRIPTION

[0025] In order to make the technical problems, technical solutions and beneficial effects of the application clearer, the application will be further described in detail below with reference to the embodiments. It should be understood that the specific embodiments described herein are only used to explain the application and do not limit the application.

[0026] In the present application, the term "and / or", which describes the association relationship of the associated objects, indicates that there can be three kinds of relationships, for example, A and / or B can represent the following three cases: A exists alone, A and B exist together, and B exists alone. Wherein A and B can be singular or plural. The character " / " generally represents an "or" relationship between the front and rear associated objects.

[0027] The terms used in the embodiments of the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application. The singular forms "a", "said" and "the" used in the embodiments of the present application and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise.

[0028] The weight of the related components mentioned in the embodiments of the present application can not only refer to the specific content of each component, but also represent the weight ratio relationship between each component. Therefore, as long as the content of the related components in the embodiments of the present application is enlarged or reduced in proportion, it is within the scope disclosed in the embodiments of the present application. Specifically, the mass mentioned in the embodiments of the present application can be μg, mg, g, kg and other mass units commonly known in the biochemical field.

[0029] Embodiment 1

[0030] Embodiment 1 of the present application provides a flame retardant, a flame-retardant nylon fabric and a preparation method thereof, comprising the following steps:

[0031] (1) Pretreatment of nylon 6 fabric

[0032] Prepare a 4wt% NaOH solution, immerse the nylon 6 fabric in the solution for 24h, then rinse with deionized water several times until the nylon 6 fabric is nearly neutral, and dry at 80℃ for standby.

[0033] (2) Preparation of flame retardant

[0034] Dissolve 7.69g of ammonium sulfamate in 100mL of deionized water, stir until completely dissolved, and the molar concentration of ammonium sulfamate is 0.80mol / L.

[0035] (3) Preparation of flame-retardant nylon 6 fabric

[0036] Immerse the pretreated nylon 6 fabric of step (1) in the solution of step (2) for 3h; dry the nylon 6 fabric after immersion treatment at 80℃ for 15min and solidify at 160℃ for 10min.

[0037] Embodiment 2

[0038] Embodiment 2 of the present application provides a flame retardant, a flame-retardant nylon fabric and a preparation method thereof, comprising the following steps:

[0039] (1) Pretreatment of nylon 6 fabric

[0040] A 4wt% NaOH solution was prepared, and the nylon 6 fabric was soaked in the solution for 24 h, and then washed with deionized water for several times until the nylon 6 fabric was nearly neutral, and dried at 80°C for standby.

[0041] (2) Preparation of flame retardant

[0042] 0.66 g of melamine was dissolved in 100 mL of deionized water, heated to complete dissolution, and the concentration of melamine was 6.6 g / L.

[0043] (3) Preparation of flame-retardant nylon 6 fabric

[0044] The pretreated nylon 6 fabric of step (1) was immersed in the solution of step (2) for 3 h; the nylon 6 fabric after immersion treatment was dried at 80°C for 15 min and cured at 160°C for 10 min.

[0045] Example 3

[0046] The application example 3 provides a flame retardant, a flame-retardant nylon fabric and a preparation method thereof, comprising the following steps:

[0047] (1) Pretreatment of nylon 6 fabric

[0048] A 4wt% NaOH solution was prepared, and the nylon 6 fabric was soaked in the solution for 24 h, and then washed with deionized water for several times until the nylon 6 fabric was nearly neutral, and dried at 80°C for standby.

[0049] (2) Preparation of flame retardant

[0050] 28 mL of triethyl phosphonoacetate was added to 72 mL of deionized water and stirred uniformly; the molar concentration of triethyl phosphonoacetate was 1.29 mol / L.

[0051] (3) Preparation of flame-retardant nylon 6 fabric

[0052] The pretreated nylon 6 fabric of step (1) was immersed in the solution of step (2) for 3 h; the nylon 6 fabric after immersion treatment was dried at 80°C for 15 min and cured at 160°C for 10 min.

[0053] Example 4

[0054] The application example 4 provides a flame retardant, a flame-retardant nylon fabric and a preparation method thereof, comprising the following steps:

[0055] (1) Pretreatment of nylon 6 fabric

[0056] Prepare a 4wt% NaOH solution, and immerse the nylon 6 fabric in the solution for 24 hours. Then, rinse the nylon 6 fabric with deionized water for several times until the fabric is nearly neutral, and dry the fabric at 80°C for standby.

[0057] (2) Preparation of the flame retardant

[0058] Dissolve 7.69 g of ammonium sulfamate and 0.66 g of melamine in 72 mL of deionized water. After complete dissolution by heating, add 28 mL of triethyl phosphonoacetate, and stir to form a mixture system. In the system, the molar concentration of ammonium sulfamate is 0.80 mol / L, the concentration of melamine is 6.6 g / L, and the molar concentration of triethyl phosphonoacetate is 1.29 mol / L.

[0059] (3) Preparation of the flame-retardant nylon 6 fabric

[0060] Immerse the pretreated nylon 6 fabric in step (1) in the phosphorus / nitrogen / sulfur flame retardant solution in step (2) for 3 hours. Dry the nylon 6 fabric after the immersion treatment, and bake at 80°C for 15 minutes and cure at 160°C for 10 minutes.

[0061] Example 5

[0062] The present application provides a flame retardant, a flame-retardant nylon fabric, and a preparation method thereof, which comprises the following steps:

[0063] (1) Pretreatment of the nylon 6 fabric

[0064] Prepare a 4wt% NaOH solution, and immerse the nylon 6 fabric in the solution for 24 hours. Then, rinse the nylon 6 fabric with deionized water for several times until the fabric is nearly neutral, and dry the fabric at 80°C for standby.

[0065] (2) Preparation of the flame retardant

[0066] Dissolve 7.69 g of ammonium sulfamate and 0.66 g of melamine in 36 mL of deionized water and 36 mL of anhydrous ethanol mixed solvent. After complete dissolution by heating, add 28 mL of triethyl phosphonoacetate, and stir to form a mixture system. In the system, the molar concentration of ammonium sulfamate is 0.80 mol / L, the concentration of melamine is 6.6 g / L, and the molar concentration of triethyl phosphonoacetate is 1.29 mol / L.

[0067] (3) Preparation of the flame-retardant nylon 6 fabric

[0068] Immerse the pretreated nylon 6 fabric in step (1) in the phosphorus / nitrogen / sulfur flame retardant solution in step (2) for 3 hours. Dry the nylon 6 fabric after the immersion treatment, and bake at 80°C for 15 minutes and cure at 160°C for 10 minutes.

[0069] Example 6

[0070] Example 6 of the present application provides a flame retardant, a flame retardant nylon fabric and a preparation method thereof, comprising the following steps:

[0071] (1) Pretreatment of nylon 6 fabric

[0072] Prepare a 4wt% NaOH solution, immerse the nylon 6 fabric in the solution for 24h, then rinse with deionized water several times until the nylon 6 fabric is nearly neutral, and dry at 80°C for standby.

[0073] (2) Preparation of flame retardant

[0074] Dissolve 7.69g of ammonium sulfamate and 0.66g of melamine in 100mL of deionized water, heat to completely dissolve, and form a mixture system 1; add 28mL of triethyl phosphonoacetate to 72mL of anhydrous ethanol, stir uniformly to form system 2; in system 1, the molar concentration of ammonium sulfamate is 0.80mol / L, and the concentration of melamine is 6.6g / L; in system 2, the molar concentration of triethyl phosphonoacetate is 1.29mol / L.

[0075] (3) Preparation of flame retardant nylon 6 fabric

[0076] Immerse the pretreated nylon 6 fabric of step (1) in system 1 for 2h, then dry at 80°C for 15min, then immerse in system 2 for 10min, and cure at 160°C for 10min to obtain the flame retardant nylon fabric.

[0077] Test the limiting oxygen index (LOI: %) and the melt dripping performance of the flame retardant fabric prepared in Examples 1-6 of the present application, and the results are shown in Table 1. The test conditions are as follows:

[0078] Limiting oxygen index test: According to the standard of GB / T5454 1997 Textile Burning Performance Determination Oxygen Index Method, the test method is to place the sample in a vertical test condition, and the lowest oxygen concentration (also called limiting oxygen index) that can just maintain combustion in the oxygen and nitrogen mixed gas flow. The sample is clamped on the sample clamp and placed vertically in the combustion cylinder. In the upward flowing oxygen stream, the upper end of the sample is ignited, the combustion characteristics are observed, and the afterburning time (not more than 2min) or the damage length (not more than 40mm) is compared with the specified limit. Through the test of a series of samples in different oxygen concentrations, the lowest oxygen concentration value expressed by the percentage of oxygen that can maintain combustion can be measured.

[0079] Melt dripping performance test: Vertical burning method is used, the fabric is ignited with a 4cm long flame for 3 seconds, the flame is removed until the burning ends, and the presence or absence of melt dripping is observed, and the result is expressed in words.

[0080] Table 1

[0081]

[0082] According to the test results in Table 1, it can be seen that the LOI of the flame-retardant nylon fabric prepared in Examples 1, 4-6 is much higher after dipping than before dipping, and there is no dripping phenomenon. The LOI of the flame-retardant fabric prepared in Examples 1, 4-6 is 29.6%, 35.1%, 37.8% and 42.4% respectively, and Examples 1 reaches the difficult-to-burn standard, and Examples 4-6 reach the non-combustible standard (flammable: LOI < 20%; combustible: LOI between 20%-27%; difficult-to-burn: LOI between 27%-35%; non-combustible: LOI > 35%), which shows that the flame-retardant nylon fabric prepared in Examples 1, 4-6 has very excellent flame-retardant performance, and the dripping phenomenon is also significantly improved. The flame-retardant performance of the flame-retardant fabric prepared in Examples 2 and 3 only reaches the combustible standard. The comparison of the test results of Examples 1-3 and Examples 4-6 shows that the flame-retardant agents can play a synergistic flame-retardant effect.

[0083] The preparation method of the nylon fabric in Example 6 is different from that in Examples 4 and 5. Example 6 uses step-by-step dipping, while Examples 4 and 5 use one-step dipping. However, the limiting oxygen index test effect of Example 6 is the best. In the one-step dipping method, the alkyl phosphate ester is added to the solution, and the phosphate ester group will hydrolyze to form a phosphate group, which is not easy to react with the amino group in the melamine and sulfur / nitrogen compound to form an amide. In Example 6, step-by-step dipping is used to avoid the hydrolysis of the phosphate ester group. Under alkaline and high temperature conditions, the ester group reacts with the amino group to form an amide, which has a similar affinity with the nylon fabric with an amide structure. Under high temperature conditions, the swelling of the nylon fiber increases the specific surface area, which is more conducive to the adsorption of the flame retardant and the nylon fabric. Therefore, the flame-retardant nylon fabric prepared by step-by-step dipping in Example 6 has better flame-retardant effect than Examples 4 and 5.

[0084] The above examples only express several embodiments of the present application, and the description is more specific and detailed, but it cannot be understood as limiting the scope of the patent of the present application. It should be noted that for ordinary skilled persons in the art, without departing from the concept of the present application, several modifications and improvements can be made, which are within the scope of protection of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

Claims

1. A flame retardant for nylon fabrics, characterized in that, Includes the following components: alkyl phosphates, sulfur / nitrogen compounds, melamine, and solvents; The alkyl phosphate ester is triethyl phosphonoacetate; The sulfur / nitrogen compound is ammonium aminosulfonate; The molar concentration of the alkyl phosphate ester is 0.8~1.5 mol / L, the molar concentration of the sulfur / nitrogen compound is 0.6~1.0 mol / L, and the concentration of the melamine is 3~10 g / L.

2. A method for preparing a flame retardant for nylon fabrics as described in claim 1, characterized in that, Includes the following steps: Sulfur / nitrogen compounds and melamine are dissolved in a solvent. After complete dissolution, alkyl phosphates are added and stirred until homogeneous to form a mixture system.

3. The application of a flame retardant for nylon fabrics as described in claim 1 in the preparation of flame retardant fabrics.

4. A flame-retardant nylon fabric, characterized in that, The nylon fabric is prepared by the following method: pre-treating the nylon fabric; immersing the pre-treated nylon fabric in a flame retardant containing the flame retardant of claim 1, and then drying and curing it to obtain a durable flame retardant nylon fabric.

5. The flame-retardant nylon fabric as described in claim 4, characterized in that, The process of immersing the pretreated nylon fabric in the flame retardant of claim 1 is carried out in a stepwise immersion process: first, the pretreated nylon fabric is immersed in a system containing sulfur / nitrogen-based compounds and melamine, and then dried after the first immersion. The nylon fabric, after the first impregnation treatment, is then impregnated in a system containing alkyl phosphate esters, followed by a second impregnation and curing.

6. A flame-retardant nylon fabric as described in claim 4, characterized in that, The drying process involves baking at 80°C for 10-20 minutes, and the curing process involves baking at 180°C for 5-10 minutes; and / or, The pretreatment involves immersing the nylon fabric in a 1-5 wt% sodium hydroxide or sodium carbonate solution for 20-24 hours, then washing it with water until nearly neutral, and drying it at 70-80°C; and / or, The nylon fabric is polyamide 6 or polyamide 66.

7. The flame-retardant nylon fabric as described in claim 5, characterized in that, The first immersion time is 1-5 hours, and the second immersion time is 5-10 minutes.

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