A silicon-containing multi-element synergistic flame retardant finishing liquid and modified nylon 6 fabric and their preparation method

Abstract

This invention belongs to the field of textile flame retardant finishing technology, and discloses a silicon-containing multi-element synergistic flame retardant finishing liquid, modified nylon 6 fabric, and their preparation method. The silicon-containing multi-element synergistic flame retardant finishing liquid comprises: 10-25% silicon-containing multi-element synergistic flame retardant and 75-90% organic solvent; the silicon-containing multi-element synergistic flame retardant includes multi-element organosiloxane flame retardants and synergistic flame retardants. The silicon-containing multi-element synergistic flame retardant finishing liquid obtained by this invention can directly impregnate nylon 6 fabrics, resulting in modified nylon 6 fabrics with a limiting oxygen index of over 26%, a heat release rate reduction of over 40%, no flaming dripping, and minimal changes in breaking strength and elongation at break. It also avoids the generation of large amounts of toxic byproducts, better aligning with modern green and environmentally friendly concepts and meeting the requirements of sustainable development.

Description

Technical Field

[0001] This invention relates to the field of flame retardant finishing technology for textiles, and in particular to a silicon-containing multi-element synergistic flame retardant finishing liquid and a modified nylon 6 fabric and its preparation method. Background Technology

[0002] Nylon 6 fabric, due to its high strength, abrasion resistance, softness, and lightweight, is widely used in various fields of production and daily life, such as backpacks, waterproof jackets, outdoor tents, parachutes, and military tarpaulins. However, nylon 6 fabric is a flammable material with extremely serious fire safety hazards. Its limiting oxygen index is only 21.5%, and once ignited, it can burn violently directly in the air, releasing a large amount of heat. At the same time, it also produces a large number of flaming droplets during combustion, which can easily spread the fire or cause burns. This hazard greatly limits the further application of nylon 6 fabric.

[0003] Currently, halogenated flame retardants hold the largest market share in the field of flame-retardant nylon 6 and its fabric products. However, halogenated flame retardants produce a large number of toxic byproducts after combustion. Therefore, halogen-free, environmentally friendly, and highly efficient flame retardants for nylon 6 fabrics have become the main trend in their research and development. Among these, silicon-based flame retardants, due to their halogen-free nature, environmental friendliness, and excellent anti-dripping properties, are a newly emerging class of condensed-phase flame retardants in recent years. They are typically used in combination with gaseous-phase flame retardants such as phosphorus and nitrogen to maximize the flame-retardant effect. For example, patent application number 201410512615.2 discloses a method for combining an organophosphorus flame retardant with a silicon-based flame retardant to flame-retard nanofiber nylon composite materials, which improves the mechanical properties of the nylon composite material while maintaining good flame-retardant performance. Li Faxue et al. (Li Faxue, Liu Ke, Sun Yanlu et al. A phosphorus-silicon synergistic flame retardant and anti-dripping nylon 6 resin and its preparation method [P]. Zhejiang Province: CN112920410A, 2021-06-08) prepared nylon 6 prepolymer by prepolymerization reaction of caprolactam and phosphorus flame retardant end-capping agent, then prepared nylon 6 esterified by esterification reaction of nylon 6 prepolymer and glycol, and finally prepared phosphorus-silicon synergistic flame retardant and anti-dripping nylon 6 resin by transesterification reaction of nylon 6 esterified by silicon flame retardant. The obtained nylon 6 resin has a limiting oxygen index of 28.6%, a UL94 rating of V-0, and no dripping during combustion. Patent application number 202010388109.2 describes a compound of hypophosphite-cyclotetrasiloxane bi-base synergistic compound and nitrogen-based flame retardant for flame-retardant nylon 6. When the concentration of the compounded flame retardant reaches 12%, the limiting oxygen index of the nylon 6 composite material increases to 31.5%, but the tensile strength and notched impact strength of the nylon 6 composite material both decrease. Furthermore, most commercially available silicone-based nylon 6 flame retardants are used in nylon 6 masterbatches or nylon 6 fibers, with almost none suitable for direct application to nylon 6 fabrics. Moreover, most of these applications significantly impact the mechanical properties of nylon 6. With the increasing use of nylon 6 fabrics, the development of highly efficient, environmentally friendly silicone-based flame retardants that have minimal impact on mechanical properties and can directly act on nylon 6 fabrics has become mainstream, and this is a problem that urgently needs to be solved. Summary of the Invention

[0004] The purpose of this invention is to provide a silicon-containing multi-element synergistic flame retardant finishing liquid and modified nylon 6 fabric and its preparation method, which solves the problems that existing flame retardants cannot be directly applied to nylon 6 fabrics, that flame retardants have a significant impact on the mechanical properties of nylon 6, and that the use of halogens does not conform to the concept of green environmental protection.

[0005] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0006] This invention provides a silicon-containing multi-element synergistic flame retardant finishing liquid, comprising the following raw materials by mass fraction:

[0007] Silicon-containing multi-element synergistic flame retardant 10-25%, organic solvent 75-90%;

[0008] The silicon-containing multi-component synergistic flame retardant includes multi-component organosiloxane flame retardants and synergistic flame retardants;

[0009] The multi-component organosiloxane flame retardant is prepared from raw materials comprising the following parts by weight: 10-20 parts phosphorus-containing organosiloxane, 10-20 parts unsaturated organosiloxane, 10-20 parts silane coupling agent, and 40-70 parts organic solvent.

[0010] Furthermore, in the aforementioned silicon-containing multi-component synergistic flame retardant finishing liquid, the mass ratio of the multi-component organosiloxane flame retardant to the synergistic flame retardant is 1-3:1-3; the organic solvent in the silicon-containing multi-component synergistic flame retardant finishing liquid and the organic solvent in the multi-component organosiloxane flame retardant are independently any one of ethanol, methanol, propanol, chloroform, and acetone.

[0011] Furthermore, in the aforementioned silicon-containing multi-element synergistic flame retardant finishing liquid, the structure of the phosphorus-containing organosiloxane is shown in Formula I:

[0012]

[0013] The structure of the organosiloxane containing the unsaturated group is shown in Formula II:

[0014]

[0015] In Formula I, R1 and in Formula II, R2 are independently aminoethylpropyl or propyl.

[0016] Furthermore, in the aforementioned silicon-containing multi-element synergistic flame retardant finishing liquid, the synergistic flame retardant is any one of thiourea, aminosulfonamide, and guanidine aminosulfonate; and the silane coupling agent is any one of KH550, KH560, KH570, and KH602.

[0017] Furthermore, in the aforementioned silicon-containing multi-component synergistic flame retardant finishing liquid, the preparation method of the multi-component organosiloxane flame retardant is as follows:

[0018] Phosphorus-containing organosiloxanes, organosiloxanes containing unsaturated groups, silane coupling agents and organic solvents are mixed and subjected to dehydration condensation reaction under nitrogen protection. After extraction and purification, multi-component organosiloxane flame retardants are obtained.

[0019] The temperature of the dehydration condensation reaction is 50–70°C, and the time of the dehydration condensation reaction is 3–4 hours.

[0020] The present invention also provides a modified nylon 6 fabric, which is treated with the silicon-containing multi-element synergistic flame retardant finishing liquid.

[0021] This invention also provides a method for preparing modified nylon 6 fabric, comprising the following steps:

[0022] Nylon 6 fabric was immersed in a silicon-containing multi-element synergistic flame retardant finishing liquid, and then pre-dried and cured to obtain modified nylon 6 fabric.

[0023] The nylon 6 fabric is 15-30 parts by weight, and the silicon-containing multi-element synergistic flame retardant finishing liquid is 70-85 parts by weight.

[0024] The immersion temperature is 60–100°C, and the immersion time is 4–8 hours.

[0025] The pre-drying temperature is 85–95°C, and the pre-drying time is 5–15 minutes;

[0026] The curing temperature is 120–150°C, and the curing time is 2–8 minutes.

[0027] Furthermore, in the preparation method of the modified nylon 6 fabric, the nylon 6 fabric is first modified with hydroxymethyl before being impregnated with a silicon-containing multi-element synergistic flame retardant finishing liquid. The specific steps are as follows: the nylon 6 fabric is impregnated in an aqueous solution of isopropanol, and then chloroacetic acid is added to carry out the modification reaction, followed by washing, neutralization, and drying.

[0028] The temperature of the modification reaction is 50–70°C, and the reaction time is 2–3 hours.

[0029] Furthermore, in the method for preparing the modified nylon 6 fabric, during the hydroxymethyl modification of the nylon 6 fabric, the mass fraction of the nylon 6 fabric is 5-10 parts, the mass fraction of the isopropanol aqueous solution is 80-90 parts, and the mass fraction of the chloroacetic acid is 5-10 parts.

[0030] Furthermore, in the method for preparing the modified nylon 6 fabric, the mass ratio of isopropanol to water in the aqueous solution of isopropanol is 1:2 to 4.

[0031] As can be seen from the above technical solution, compared with the prior art, the present invention has the following beneficial effects:

[0032] (1) The silicon-containing multi-element synergistic flame retardant finishing liquid prepared by the present invention can be directly impregnated with nylon 6 fabric. The modified nylon 6 fabric obtained after impregnation is tested and found to have a limiting oxygen index of more than 26%, a heat release rate of more than 40%, no flaming droplets are produced, and the changes in breaking strength and breaking elongation are small, which can better maintain the original mechanical properties of nylon 6 fabric.

[0033] (2) The raw materials used in the preparation of the silicon-containing multi-element synergistic flame retardant finishing liquid of the present invention do not contain halogens. Even if the flame retardant finishing liquid is burned, it will not produce a large number of toxic by-products, which is more in line with the green and environmentally friendly concept of modern society and meets the requirements of sustainable development. Detailed Implementation

[0034] This invention provides a silicon-containing multi-element synergistic flame retardant finishing liquid, comprising the following raw materials by mass fraction:

[0035] Silicon-containing multi-element synergistic flame retardant 10-25%, organic solvent 75-90%;

[0036] The silicon-containing multi-component synergistic flame retardant includes multi-component organosiloxane flame retardants and synergistic flame retardants;

[0037] The multi-component organosiloxane flame retardant is prepared from raw materials comprising the following parts by weight: 10-20 parts phosphorus-containing organosiloxane, 10-20 parts unsaturated organosiloxane, 10-20 parts silane coupling agent, and 40-70 parts organic solvent.

[0038] In this invention, the mass fraction of the silicon-containing multi-element synergistic flame retardant is preferably 14-22%, more preferably 15-20%, and even more preferably 20%; the mass fraction of the organic solvent is preferably 78-86%, more preferably 80-84%, and even more preferably 80%.

[0039] In this invention, the multi-component organosiloxane flame retardant is preferably prepared from raw materials comprising the following parts by weight: 13-20 parts of phosphorus-containing organosiloxane, 15-20 parts of unsaturated organosiloxane, 14-20 parts of silane coupling agent, and 40-60 parts of organic solvent; more preferably: 16-20 parts of phosphorus-containing organosiloxane, 18-20 parts of unsaturated organosiloxane, 17-20 parts of silane coupling agent, and 40-50 parts of organic solvent; more preferably: 20 parts of phosphorus-containing organosiloxane, 20 parts of unsaturated organosiloxane, 20 parts of silane coupling agent, and 40 parts of organic solvent.

[0040] In this invention, the mass ratio of the multi-component organosiloxane flame retardant to the synergistic flame retardant is preferably 1-3:1-3, more preferably 1-2:2-3, and even more preferably 1:1.

[0041] In this invention, the organic solvent in the silicon-containing multi-element synergistic flame retardant finishing liquid is preferably any one of ethanol, methanol, propanol, chloroform and acetone, more preferably methanol or acetone, and even more preferably methanol.

[0042] In this invention, the organic solvent in the multi-component organosiloxane flame retardant is preferably any one of ethanol, methanol, propanol, chloroform and acetone, more preferably ethanol, propanol or chloroform, and even more preferably ethanol.

[0043] In this invention, the structure of the phosphorus-containing organosiloxane is shown in Formula I:

[0044]

[0045] R1 in Formula I is preferably aminoethylpropyl or propyl, and more preferably aminoethylpropyl.

[0046] In this invention, the structure of the organosiloxane containing the unsaturated group is shown in Formula II:

[0047]

[0048] R2 in Formula II is preferably aminoethylpropyl or propyl, and more preferably aminoethylpropyl.

[0049] In this invention, the synergistic flame retardant is preferably any one of thiourea, aminosulfonic acid amine and aminosulfonic acid guanidine, more preferably thiourea or aminosulfonic acid amine, and more preferably aminosulfonic acid amine.

[0050] In this invention, the silane coupling agent is preferably any one of KH550, KH560, KH570 and KH602, more preferably KH550 or KH570, and even more preferably KH570.

[0051] In this invention, the preferred method for preparing the multi-component organosiloxane flame retardant is as follows:

[0052] Phosphorus-containing organosiloxanes, organosiloxanes containing unsaturated groups, silane coupling agents, and organic solvents are mixed and subjected to dehydration condensation reaction under nitrogen protection. After extraction and purification, a multi-component organosiloxane flame retardant is obtained.

[0053] In this invention, the temperature of the dehydration condensation reaction is preferably 50-70°C, more preferably 62-70°C, and even more preferably 70°C; the time of the dehydration condensation reaction is preferably 3-4 hours, more preferably 3.7-4 hours, and even more preferably 4 hours.

[0054] This invention does not limit the extraction and purification methods; any method well known to those skilled in the art can be used.

[0055] This invention also provides a method for preparing a silicon-containing multi-element synergistic flame retardant finishing liquid, comprising the following steps:

[0056] A multi-component organosiloxane flame retardant is mixed with a synergistic flame retardant to obtain a silicon-containing multi-component synergistic flame retardant, which is then added to an organic solvent and mixed thoroughly to obtain a silicon-containing multi-component synergistic flame retardant finishing liquid.

[0057] The present invention also provides a modified nylon 6 fabric, which is treated with the silicon-containing multi-element synergistic flame retardant finishing liquid.

[0058] This invention also provides a method for preparing modified nylon 6 fabric, comprising the following steps:

[0059] Nylon 6 fabric was immersed in a silicon-containing multi-element synergistic flame retardant finishing liquid, and then pre-dried and cured to obtain modified nylon 6 fabric.

[0060] In this invention, the mass fraction of the nylon 6 fabric is preferably 15 to 30 parts, more preferably 18 to 27 parts, and even more preferably 25 parts; the mass fraction of the silicon-containing multi-element synergistic flame retardant finishing liquid is preferably 70 to 85 parts, more preferably 72 to 78 parts, and even more preferably 75 parts.

[0061] In this invention, the immersion temperature is preferably 60-100°C, more preferably 60-80°C, and even more preferably 60°C; the immersion time is preferably 4-8 hours, more preferably 4-5.6 hours, and even more preferably 4 hours.

[0062] In this invention, the pre-baking temperature is preferably 85-95°C, more preferably 90-95°C, and even more preferably 95°C; the pre-baking time is preferably 5-15 min, more preferably 5-8 min, and even more preferably 5 min.

[0063] In this invention, the curing temperature is preferably 120-150°C, more preferably 138-150°C, and even more preferably 150°C; the curing time is preferably 2-8 min, more preferably 4-6 min, and even more preferably 5 min.

[0064] In this invention, the nylon 6 fabric is preferably modified with hydroxymethyl before being immersed in a silicon-containing multi-element synergistic flame retardant finishing liquid. The specific steps are as follows: the nylon 6 fabric is immersed in an aqueous solution of isopropanol, and then chloroacetic acid is added to carry out the modification reaction, followed by washing, neutralization, and drying.

[0065] In this invention, the temperature of the modification reaction is preferably 50-70°C, more preferably 50-56°C, and even more preferably 50°C; the time of the modification reaction is preferably 2-3 hours, more preferably 2.6-3 hours, and even more preferably 3 hours.

[0066] The present invention does not limit the number of times of washing, neutralizing and drying; any solution known to those skilled in the art can be used.

[0067] In this invention, during the hydroxymethyl modification of the nylon 6 fabric, the mass fraction of the nylon 6 fabric is preferably 5 to 10 parts, more preferably 8 to 10 parts, and even more preferably 10 parts; the mass fraction of the isopropanol aqueous solution is preferably 80 to 90 parts, more preferably 80 to 84 parts, and even more preferably 80 parts; the mass fraction of the chloroacetic acid is preferably 5 to 10 parts, more preferably 9 to 10 parts, and even more preferably 10 parts.

[0068] In this invention, the mass ratio of isopropanol to water in the aqueous solution of isopropanol is preferably 1:2 to 4, more preferably 1:2.6 to 3.2, and even more preferably 1:3.

[0069] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0070] Example 1

[0071] This embodiment provides a method for preparing a silicon-containing multi-element synergistic flame retardant finishing liquid, including the following steps:

[0072]

[0073] (1) Preparation of multi-component organosiloxane flame retardant: 20 parts of phosphorus-containing organosiloxane (as shown in Formula I), 20 parts of unsaturated group-containing organosiloxane (as shown in Formula II), 20 parts of silane coupling agent KH550 and 40 parts of ethanol were added to a reaction vessel and mixed. Nitrogen gas was introduced to replace the air in the vessel. The dehydration condensation reaction was carried out at 50°C for 3 hours. After extraction and purification, the multi-component organosiloxane flame retardant was obtained.

[0074] (2) Mix the multi-component organosiloxane flame retardant and thiourea at a mass ratio of 3:2 to obtain a silicon-containing multi-component synergistic flame retardant, and then add it to ethanol and mix thoroughly to obtain a silicon-containing multi-component synergistic flame retardant finishing liquid with a total flame retardant mass concentration of 20%.

[0075] This embodiment also provides a method for preparing modified nylon 6 fabric, including the following steps:

[0076] Ten parts of nylon 6 fabric were immersed in an aqueous solution of 80 parts isopropanol (the mass ratio of isopropanol to water was 1:3). After complete immersion, 10 parts of chloroacetic acid were added, and the mixture was shaken and reacted at 50°C for 3 hours. After repeated washing, neutralization, and drying, hydroxymethyl modified nylon 6 fabric was obtained. Fifteen parts of hydroxymethyl modified nylon 6 fabric were completely immersed in 85 parts of a silicon-containing multi-element synergistic flame retardant finishing liquid with a total mass concentration of 20%. The mixture was reacted at 60°C for 4 hours, and then placed in an oven. The mixture was first pre-dried at 95°C for 5 minutes, and then heated to 150°C for 3 minutes to cure, thus obtaining modified nylon 6 fabric.

[0077] Tests showed that, compared with pure nylon 6 fabric, the modified nylon 6 fabric obtained in Example 1 had a limiting oxygen index of 26%, a heat release rate that decreased by 45%, a breaking strength that decreased by 2.1%, and a breaking elongation that decreased by 3.2%.

[0078] Example 2

[0079] This embodiment provides a method for preparing a silicon-containing multi-element synergistic flame retardant finishing liquid, including the following steps:

[0080]

[0081] (1) Preparation of multi-component organosiloxane flame retardant: 10 parts of phosphorus-containing organosiloxane (as shown in Formula I), 10 parts of unsaturated group-containing organosiloxane (as shown in Formula II), 10 parts of silane coupling agent KH560 and 70 parts of methanol were added to a reaction vessel and mixed. Nitrogen gas was introduced to replace the air in the vessel. The dehydration condensation reaction was carried out at 60°C for 3 hours. After extraction and purification, the multi-component organosiloxane flame retardant was obtained.

[0082] (2) Mix the multi-component organosiloxane flame retardant with guanidine aminosulfonate at a mass ratio of 2:3 to obtain a silicon-containing multi-component synergistic flame retardant. Then add it to methanol and mix thoroughly to obtain a silicon-containing multi-component synergistic flame retardant finishing liquid with a total flame retardant mass concentration of 20%.

[0083] This embodiment also provides a method for preparing modified nylon 6 fabric, including the following steps:

[0084] Ten parts of nylon 6 fabric were immersed in an aqueous solution of 80 parts isopropanol (the mass ratio of isopropanol to water was 1:3). After complete immersion, 10 parts of chloroacetic acid were added, and the mixture was shaken and reacted at 50°C for 3 hours. After repeated washing, neutralization, and drying, hydroxymethyl modified nylon 6 fabric was obtained. Twenty parts of hydroxymethyl modified nylon 6 fabric were completely immersed in 80 parts of a silicon-containing multi-element synergistic flame retardant finishing liquid with a total mass concentration of 20%. The mixture was reacted at 60°C for 4 hours, and then placed in an oven. The mixture was first pre-dried at 95°C for 5 minutes, and then heated to 150°C for 3 minutes to cure, thus obtaining modified nylon 6 fabric.

[0085] Tests showed that, compared with pure nylon 6 fabric, the modified nylon 6 fabric obtained in Example 2 had a limiting oxygen index of 27%, a heat release rate that decreased by 50%, a breaking strength that decreased by 2.4%, and a breaking elongation that decreased by 3.5%.

[0086] Example 3

[0087] This embodiment provides a method for preparing a silicon-containing multi-element synergistic flame retardant finishing liquid, including the following steps:

[0088]

[0089] (1) Preparation of multi-component organosiloxane flame retardant: 20 parts of phosphorus-containing organosiloxane (as shown in Formula I), 20 parts of unsaturated group-containing organosiloxane (as shown in Formula II), 20 parts of silane coupling agent KH602 and 40 parts of propanol were added to a reaction vessel and mixed. Nitrogen gas was introduced to replace the air in the vessel. The dehydration condensation reaction was carried out at 70°C for 4 hours. After extraction and purification, the multi-component organosiloxane flame retardant was obtained.

[0090] (2) Mix the multi-component organosiloxane flame retardant and aminosulfonic acid amine at a mass ratio of 2:3 to obtain a silicon-containing multi-component synergistic flame retardant, and then add it to propanol and mix thoroughly to obtain a silicon-containing multi-component synergistic flame retardant finishing liquid with a total flame retardant mass concentration of 15%.

[0091] This embodiment also provides a method for preparing modified nylon 6 fabric, including the following steps:

[0092] Ten parts of nylon 6 fabric were immersed in an aqueous solution of 80 parts isopropanol (the mass ratio of isopropanol to water was 1:3). After complete immersion, 10 parts of chloroacetic acid were added, and the mixture was shaken and reacted at 50°C for 3 hours. After repeated washing, neutralization, and drying, hydroxymethyl modified nylon 6 fabric was obtained. Thirty parts of hydroxymethyl modified nylon 6 fabric were completely immersed in a 70-part, 15% total mass concentration silicon-containing multi-element synergistic flame retardant finishing liquid. The mixture was reacted at 60°C for 4 hours, and then placed in an oven. It was first pre-dried at 95°C for 5 minutes, and then heated to 150°C for 5 minutes to cure, thus obtaining modified nylon 6 fabric.

[0093] Tests showed that, compared with pure nylon 6 fabric, the modified nylon 6 fabric obtained in Example 3 had a limiting oxygen index of 26.8%, a heat release rate that decreased by 43%, a breaking strength that decreased by 3%, and a breaking elongation that decreased by 3.7%.

[0094] Example 4

[0095] This embodiment provides a method for preparing a silicon-containing multi-element synergistic flame retardant finishing liquid, including the following steps:

[0096]

[0097] (1) Preparation of multi-component organosiloxane flame retardant: 15 parts of phosphorus-containing organosiloxane (as shown in Formula I), 15 parts of unsaturated group-containing organosiloxane (as shown in Formula II), 20 parts of silane coupling agent KH570 and 40 parts of chloroform were added to a reaction vessel and mixed. Nitrogen gas was introduced to replace the air in the vessel. The dehydration condensation reaction was carried out at 70°C for 4 hours. After extraction and purification, the multi-component organosiloxane flame retardant was obtained.

[0098] (2) Mix the multi-component organosiloxane flame retardant and thiourea at a mass ratio of 1:1 to obtain a silicon-containing multi-component synergistic flame retardant, and then add it to chloroform and mix thoroughly to obtain a silicon-containing multi-component synergistic flame retardant finishing liquid with a total flame retardant mass concentration of 10%.

[0099] This embodiment also provides a method for preparing modified nylon 6 fabric, including the following steps:

[0100] Ten parts of nylon 6 fabric were immersed in an aqueous solution of 80 parts isopropanol (the mass ratio of isopropanol to water was 1:2). After complete immersion, 10 parts of chloroacetic acid were added, and the mixture was shaken and reacted at 50°C for 3 hours. After repeated washing, neutralization, and drying, hydroxymethyl modified nylon 6 fabric was obtained. Twenty-five parts of hydroxymethyl modified nylon 6 fabric were completely immersed in a 75-part, 10% total mass concentration silicon-containing multi-element synergistic flame retardant finishing liquid. The mixture was reacted at 70°C for 4 hours, and then placed in an oven. It was pre-dried at 95°C for 5 minutes, and then heated to 120°C for 8 minutes to cure, thus obtaining modified nylon 6 fabric.

[0101] Tests showed that, compared with pure nylon 6 fabric, the modified nylon 6 fabric obtained in Example 4 had a limiting oxygen index of 26.6%, a heat release rate that decreased by 40%, a breaking strength that decreased by 2.1%, and a breaking elongation that decreased by 2.7%.

[0102] Example 5

[0103] This embodiment provides a method for preparing a silicon-containing multi-element synergistic flame retardant finishing liquid, including the following steps:

[0104]

[0105] (1) Preparation of multi-component organosiloxane flame retardant: 20 parts of phosphorus-containing organosiloxane (as shown in Formula I), 20 parts of unsaturated group-containing organosiloxane (as shown in Formula II), 20 parts of silane coupling agent KH570 and 40 parts of methanol were added to a reaction vessel and mixed. Nitrogen gas was introduced to replace the air in the vessel. The dehydration condensation reaction was carried out at 70°C for 4 hours. After extraction and purification, the multi-component organosiloxane flame retardant was obtained.

[0106] (2) Mix the multi-component organosiloxane flame retardant and aminosulfonate amine at a mass ratio of 1:1 to obtain a silicon-containing multi-component synergistic flame retardant, and then add it to methanol and mix thoroughly to obtain a silicon-containing multi-component synergistic flame retardant finishing liquid with a total flame retardant mass concentration of 15%.

[0107] This embodiment also provides a method for preparing modified nylon 6 fabric, including the following steps:

[0108] Ten parts of nylon 6 fabric were immersed in an aqueous solution of 80 parts isopropanol (the mass ratio of isopropanol to water was 1:3). After complete immersion, 10 parts of chloroacetic acid were added, and the mixture was shaken and reacted at 50°C for 3 hours. After repeated washing, neutralization, and drying, hydroxymethyl modified nylon 6 fabric was obtained. Twenty parts of hydroxymethyl modified nylon 6 fabric were completely immersed in 80 parts of a silicon-containing multi-element synergistic flame retardant finishing liquid with a total mass concentration of 15%. The mixture was reacted at 60°C for 4 hours, and then placed in an oven. The mixture was first pre-dried at 95°C for 5 minutes, and then heated to 150°C for 5 minutes to cure, thus obtaining modified nylon 6 fabric.

[0109] Tests showed that, compared with pure nylon 6 fabric, the modified nylon 6 fabric obtained in Example 5 had a limiting oxygen index of 27.3%, a heat release rate that decreased by 41%, a breaking strength that decreased by 2.0%, and a breaking elongation that decreased by 2.4%.

[0110] Example 6

[0111] This embodiment provides a method for preparing a silicon-containing multi-element synergistic flame retardant finishing liquid, including the following steps:

[0112]

[0113]

[0114] (1) Preparation of multi-component organosiloxane flame retardant: 20 parts of phosphorus-containing organosiloxane (as shown in Formula I), 20 parts of unsaturated group-containing organosiloxane (as shown in Formula II), 20 parts of silane coupling agent KH570 and 40 parts of acetone were added to a reaction vessel and mixed. Nitrogen gas was introduced to replace the air in the vessel. The dehydration condensation reaction was carried out at 70°C for 4 hours. After extraction and purification, the multi-component organosiloxane flame retardant was obtained.

[0115] (2) Mix the multi-component organosiloxane flame retardant with guanidine aminosulfonate at a mass ratio of 1:1 to obtain a silicon-containing multi-component synergistic flame retardant, and then add it to acetone and mix thoroughly to obtain a silicon-containing multi-component synergistic flame retardant finishing liquid with a total flame retardant mass concentration of 10%.

[0116] This embodiment also provides a method for preparing modified nylon 6 fabric, including the following steps:

[0117] Ten parts of nylon 6 fabric were immersed in an aqueous solution of 80 parts isopropanol (the mass ratio of isopropanol to water was 1:3). After complete immersion, 10 parts of chloroacetic acid were added, and the mixture was shaken and reacted at 50°C for 3 hours. After repeated washing, neutralization, and drying, hydroxymethyl modified nylon 6 fabric was obtained. Fifteen parts of hydroxymethyl modified nylon 6 fabric were completely immersed in 85 parts of a silicon-containing multi-element synergistic flame retardant finishing liquid with a total mass concentration of 10%. The mixture was reacted at 60°C for 4 hours, and then placed in an oven. The mixture was first pre-dried at 95°C for 5 minutes, and then heated to 150°C for 5 minutes to cure, thus obtaining modified nylon 6 fabric.

[0118] Tests showed that, compared with pure nylon 6 fabric, the modified nylon 6 fabric obtained in Example 6 had a limiting oxygen index of 26.8%, a heat release rate that decreased by 41%, a breaking strength that decreased by 2.2%, and a breaking elongation that decreased by 2.8%.

[0119] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A silicon-containing multi-element synergistic flame retardant finishing liquid, characterized in that, Raw materials containing the following mass fractions: Silicon-containing multi-element synergistic flame retardant 10-25%, organic solvent 75-90%; The silicon-containing multi-component synergistic flame retardant includes multi-component organosiloxane flame retardants and synergistic flame retardants; The multi-component organosiloxane flame retardant is prepared from raw materials comprising the following parts by weight: 10-20 parts phosphorus-containing organosiloxane, 10-20 parts unsaturated organosiloxane, 10-20 parts silane coupling agent, and 40-70 parts organic solvent. The structure of the phosphorus-containing organosiloxane is shown in Formula I: The structure of the organosiloxane containing the unsaturated group is shown in Formula II: In Formula I, R1 and in Formula II, R2 are independently aminoethylpropyl or propyl; The synergistic flame retardant is any one of thiourea, aminosulfonamide, and guanidine aminosulfonate; the silane coupling agent is any one of KH550, KH560, KH570, and KH602.

2. The silicon-containing multi-element synergistic flame retardant finishing liquid as described in claim 1, characterized in that, The mass ratio of the multi-component organosiloxane flame retardant to the synergistic flame retardant is 1-3:1-3; the organic solvent in the silicon-containing multi-component synergistic flame retardant finishing liquid and the organic solvent in the multi-component organosiloxane flame retardant are independently any one of ethanol, methanol, propanol, chloroform and acetone.

3. The silicon-containing multi-element synergistic flame retardant finishing liquid as described in claim 1 or 2, characterized in that, The preparation method of the multi-component organosiloxane flame retardant is as follows: Phosphorus-containing organosiloxanes, organosiloxanes containing unsaturated groups, silane coupling agents and organic solvents are mixed and subjected to dehydration condensation reaction under nitrogen protection. After extraction and purification, multi-component organosiloxane flame retardants are obtained. The temperature of the dehydration condensation reaction is 50–70°C, and the time of the dehydration condensation reaction is 3–4 hours.

4. A modified nylon 6 fabric, characterized in that, The fabric is treated with the silicon-containing multi-element synergistic flame retardant finishing liquid according to any one of claims 1 to 3.

5. The method for preparing a modified nylon 6 fabric according to claim 4, characterized in that, Includes the following steps: Nylon 6 fabric was immersed in a silicon-containing multi-element synergistic flame retardant finishing liquid, and then pre-dried and cured to obtain modified nylon 6 fabric. The nylon 6 fabric is 15-30 parts by weight, and the silicon-containing multi-element synergistic flame retardant finishing liquid is 70-85 parts by weight. The immersion temperature is 60–100°C, and the immersion time is 4–8 hours. The pre-drying temperature is 85–95°C, and the pre-drying time is 5–15 minutes; The curing temperature is 120–150°C, and the curing time is 2–8 minutes.

6. The method for preparing a modified nylon 6 fabric as described in claim 5, characterized in that, The nylon 6 fabric is first modified with hydroxymethyl before being immersed in a silicon-containing multi-element synergistic flame retardant finishing liquid. The specific steps are as follows: the nylon 6 fabric is immersed in an aqueous solution of isopropanol, and then chloroacetic acid is added to carry out the modification reaction, followed by washing, neutralization, and drying. The temperature of the modification reaction is 50–70°C, and the reaction time is 2–3 hours.

7. The method for preparing a modified nylon 6 fabric as described in claim 6, characterized in that, In the hydroxymethyl modification of the nylon 6 fabric, the nylon 6 fabric accounts for 5 to 10 parts by mass, the isopropanol aqueous solution accounts for 80 to 90 parts by mass, and the chloroacetic acid accounts for 5 to 10 parts by mass.

8. A method for preparing a modified nylon 6 fabric as described in claim 6 or 7, characterized in that, In the aqueous solution of isopropanol, the mass ratio of isopropanol to water is 1:2 to 4.