A method for flame retardant finishing of nylon 6 fabric using waste wool solution

Abstract

The present invention belongs to the technical field of flame-retardant fabrics, and relates to a method for flame-retardant finishing of nylon 6 fabric with waste wool dissolving liquid, and the method is specifically as follows: firstly, the waste wool is immersed in a solution containing both aminotrimethylenephosphonic acid and dicyandiamide at a temperature above 55°C, and then the waste wool is immersed in a sodium silicate solution at a temperature above 85°C to obtain a wool dissolving liquid, and finally the wool dissolving liquid is used to flame-retardant finish the nylon 6 fabric to obtain a flame-retardant nylon 6 fabric. The present invention adopts an environmentally friendly flame retardant system to obtain a nylon 6 fabric with excellent flame retardant properties.

Description

Technical Field

[0001] The invention belongs to the technical field of flame-retardant fabrics, and particularly relates to a method for flame-retardant finishing of nylon 6 fabric using waste wool dissolving liquid. Background Art

[0002] Nylon 6 is a synthetic fiber with advantages such as good wear resistance, high resilience and high breaking strength, so it is widely used in clothing, home textiles and industrial products. However, nylon 6 fiber is a flammable fiber. Its easy combustion and the characteristics of molten droplets bring potential fire hazards, so it is particularly important to improve the flame retardant properties of nylon 6 fabrics.

[0003] It is worth noting that keratin, a substance widely present in various animals, exhibits excellent carbon-forming properties due to its high nitrogen and sulfur content. Among them, wool fiber is a rich protein resource.

[0004] The literature (Preparation of wool keratin and flame retardant finishing of cotton fabrics [J]. Printing and Dyeing, 2022, 48(12): 43-47.) used oxidation and reduction methods to dissolve waste wool to prepare keratin solutions, and then flame retardant finishing was performed on cotton fabrics. The keratin solution prepared by sodium sulfide reduction method had a higher concentration and showed good flame retardant effect. Its LOI value reached 26.5% and the afterburning time was 2.00s. It can be seen that the good carbonization of wool keratin helps to improve the flame retardant properties of cotton fabrics, and the wool solution does have a certain effect in flame retardancy.

[0005] In actual application, technicians referred to the above literature and tried to use wool dissolving liquid to flame retardant finish nylon 6 fabric. However, since cotton fabric and nylon 6 fabric are made of different materials, the flame retardant effect of nylon 6 fabric after flame retardant finishing with wool dissolving liquid did not meet expectations.

[0006] Therefore, it is necessary to further study how to use wool dissolving solution to flame retardant finish nylon 6 fabric to achieve better flame retardant effect. Summary of the invention

[0007] The purpose of the present invention is to solve the above-mentioned problems in the prior art and provide a method for flame retardant finishing of nylon 6 fabric using waste wool dissolving liquid.

[0008] In order to achieve the above object, the present invention adopts the following technical solution:

[0009] A method for flame retardant finishing of nylon 6 fabric using waste wool solution, comprising the following steps:

[0010] (1) Immersing the waste wool in a solution containing both aminotrimethylenephosphonic acid and dicyandiamide at a temperature above 55°C;

[0011] In this process, the ammonium phosphate structure of aminotrimethylene phosphonic acid ammonium can generate covalent bond crosslinking with the active hydroxyl group of waste wool fiber under the catalytic action of dicyandiamide, and the phosphate structure of aminotrimethylene phosphonic acid ammonium can generate ionic bond crosslinking with the amino group of waste wool fiber, thereby grafting aminotrimethylene phosphonic acid ammonium on the waste wool fiber;

[0012] The treatment temperature is controlled to be above 55°C in this stage because dicyandiamide is soluble in hot water, and heating can promote the entry of aminotrimethylenephosphonic acid ammonium into the fiber, but overheated dicyandiamide is easy to decompose and produce ammonia;

[0013] (2) immersing the waste wool treated in step (1) in a sodium silicate solution at a temperature above 85° C. to obtain a waste wool solution;

[0014] During this process, the following reactions occur simultaneously:

[0015] Sodium silicate is hydrolyzed on the surface and inside of waste wool fibers to produce poorly water-soluble silicic acid and sodium hydroxide. Sodium hydroxide destroys the hydrogen bonds and hydrophobic effects inside protein molecules, causing keratin to decompose and dissolve.

[0016] Sodium silicate and silicic acid react with the phosphate structure of ammonium aminotrimethylenephosphonate to form insoluble phosphosilicate complex salts through colloidal adsorption;

[0017] Wool keratin is a macromolecular long-chain structure, rich in amino and carboxyl groups, and can form strong ionic bonds and chelating effects with the phosphate and silica colloid of insoluble phosphosilicate complex salts, thus playing the role of dispersing insoluble phosphosilicate complex salts.

[0018] The treatment temperature is controlled to be above 85℃ in this stage because the surface of the waste fiber is rich in scales. Raising the temperature helps to open the scales of the waste fiber, allowing sodium silicate to diffuse into the waste fiber and help dissolve the waste wool.

[0019] (3) Nylon 6 fabric was treated with waste wool dissolving liquid to obtain flame retardant nylon 6 fabric.

[0020] As the preferred technical solution:

[0021] According to the method for flame retardant finishing of nylon 6 fabric with waste wool solution, in step (1), the pH value of the solution containing aminotrimethylenephosphonic acid and dicyandiamide is 7-8, and the pH value is adjusted by ammonia water. In the solution containing aminotrimethylenephosphonic acid and dicyandiamide, the concentration of aminotrimethylenephosphonic acid is 70-100 g / L, and the concentration of dicyandiamide is 30-40 g / L; the mass ratio of the waste wool to the solution containing aminotrimethylenephosphonic acid and dicyandiamide is 1:20-30.

[0022] In the method for flame retardant finishing of nylon 6 fabric with waste wool solution as described above, in step (1), the treatment temperature is 55-65°C and the treatment time is 10-20 minutes.

[0023] In the method for flame retardant finishing of nylon 6 fabric with waste wool solution as described above, in step (2), the concentration of the sodium silicate solution is 20-40 g / L, and the mass ratio of the waste wool to the sodium silicate solution is 1:30-40.

[0024] In the method for flame retardant finishing of nylon 6 fabric with waste wool solution as described above, in step (2), the treatment temperature is 85-90°C and the treatment time is 60-90 minutes.

[0025] In the method for flame retardant finishing of nylon 6 fabric with waste wool solution as described above, in step (3), the finishing is to immerse the nylon 6 fabric in the waste wool solution and treat it at above 80°C, and then dry it, and the mass ratio of the nylon 6 fabric to the waste wool solution is 1:30~40.

[0026] In the method for flame retardant finishing of nylon 6 fabric with waste wool solution as described above, in step (3), the treatment temperature is 80-90°C and the treatment time is 50-70 minutes. The higher the treatment temperature and the longer the treatment time, the more conducive it is to the adsorption of the flame retardant on the nylon 6 fabric.

[0027] A method for flame retardant finishing of nylon 6 fabric with waste wool solution as described in any of the above items, the limiting oxygen index of the flame retardant nylon 6 fabric is ≥29.8%, the damaged length is ≤10.1cm, no molten droplets are generated, and the residual carbon content after calcination at 700°C is ≥19.4%; since the phosphate structure in the waste wool solution can act as an acid source, the wool keratin acts as a gas source and a carbon source, an intumescent flame retardant system can be constructed with high carbonization efficiency, and the silica colloid can act as an acid source and help to improve the thermal stability and residual carbon content of the residual carbon, the flame retardant nylon 6 fabric has excellent flame retardant properties.

[0028] Beneficial effects:

[0029] The present invention uses aminotrimethylenephosphonic acid and sodium silicate to treat waste wool to obtain waste wool dissolving liquid, and the system belongs to an environmentally friendly flame retardant system;

[0030] In the present invention, the phosphate structure in the waste wool solution is used as an acid source, and the wool keratin is used as a gas source and a carbon source at the same time, and together they construct an efficient expansion flame retardant system. This system not only has a high carbonization efficiency, but also the silicate colloid also acts as an acid source, further enhancing the thermal stability of the residual carbon and increasing the residual carbon amount. Therefore, the flame retardant nylon 6 fabric prepared by the method of the present invention has excellent flame retardant properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is a surface morphology of the flame-retardant nylon 6 fabric prepared in Example 1 of the present invention;

[0032] Figure 2 This is a surface morphology of the carbon residue of the flame retardant nylon 6 fabric prepared in Example 1 of the present invention. DETAILED DESCRIPTION

[0033] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall within the scope limited by the appended claims of the application equally.

[0034] Testing methods for relevant performance indicators:

[0035] Limiting oxygen index: measured according to GB / T 5454-1997 using FTT0080 oxygen index instrument;

[0036] Damage length and presence of molten droplets: According to GB / T 5455-2014, the damage length is tested using an M233M vertical combustion test machine, and the presence of molten droplets is observed during the test;

[0037] Carbon residue: The sample was calcined at 700°C for 3 min in a LH-T-30 muffle furnace and then its carbon residue was tested.

[0038] Example 1

[0039] A method for flame retardant finishing of nylon 6 fabric using waste wool solution, the specific steps are as follows:

[0040] (1) Raw material preparation:

[0041] waste wool;

[0042] Aminotrimethylenephosphonic acid;

[0043] Dicyandiamide;

[0044] water;

[0045] Sodium silicate solution: the solvent is water;

[0046] ammonia;

[0047] Nylon 6 fabric: Limiting oxygen index is 20.1%, damage length is 30cm, and carbon residue after calcination at 700℃ is 0%;

[0048] (2) Preparation of waste wool solution:

[0049] (2.1) Immerse the waste wool in a mixed aqueous solution of aminotrimethylenephosphonic acid and dicyandiamide, adjust the pH value of the system to 7 with ammonia water, and treat at 55°C for 20 minutes;

[0050] Wherein, in the mixed aqueous solution of aminotrimethylenephosphonic acid and dicyandiamide, the concentration of aminotrimethylenephosphonic acid is 70 g / L, and the concentration of dicyandiamide is 30 g / L; the mass ratio of the waste wool to the mixed aqueous solution of aminotrimethylenephosphonic acid and dicyandiamide is 1:20;

[0051] (2.2) immersing the waste wool treated in step (2.1) in a sodium silicate solution at 85° C. for 90 minutes to obtain a waste wool solution;

[0052] The concentration of the sodium silicate solution is 20 g / L, and the mass ratio of waste wool to the sodium silicate solution is 1:30;

[0053] (3) Flame retardant finishing of nylon 6 fabric:

[0054] The nylon 6 fabric is immersed in waste wool solution and treated at 80°C for 70 minutes, and then dried to obtain a flame retardant nylon 6 fabric;

[0055] Among them, the mass ratio of nylon 6 fabric to waste wool solution is 1:30.

[0056] The resulting flame-retardant nylon 6 fabric had a limiting oxygen index of 29.8%, a damage length of 10.1 cm, no droplets, and a carbon residue of 19.4% after calcination at 700 °C (the morphology before and after calcination is shown in Figure 2). Figure 1 , Figure 2 as shown).

[0057] Comparative Example 1

[0058] A method for flame retardant finishing of nylon 6 fabric with waste wool solution is basically the same as Example 1, except that the present comparative example uses water of equal mass to replace the dicyandiamide in the original Example 1.

[0059] The final flame-retardant nylon 6 fabric had a limiting oxygen index of 27.3%, a damaged length of 13.5 cm, molten droplets, and a carbon residue of 5.6% after calcination at 700°C.

[0060] Compared with Example 1, the flame retardant properties of the flame retardant nylon 6 fabric prepared in Comparative Example 1 deteriorate, and the amount of residual carbon decreases. This is because when dicyandiamide is not added in Comparative Example 1, aminotrimethylenephosphonic acid ammonium is only combined with the waste wool fiber through ionic bonds, and the generated insoluble phosphosilicate complex salt is easily detached from the wool keratin and precipitated into the solution, resulting in the flame retardant system being difficult to be evenly dispersed on the surface of the nylon 6 fabric.

[0061] Comparative Example 2

[0062] A method for flame retardant finishing of nylon 6 fabric with waste wool solution is basically the same as Example 1, except that the present comparative example uses glycerol phosphate of equal mass to replace aminotrimethylene phosphonic acid in the original Example 1.

[0063] The final flame-retardant nylon 6 fabric had a limiting oxygen index of 27.9%, a damaged length of 13.2 cm, molten droplets, and a carbon residue of 5.3% after calcination at 700°C.

[0064] Compared with Example 1, the flame retardant properties of the flame retardant nylon 6 fabric prepared in Comparative Example 2 deteriorate, and the residual carbon amount decreases. This is because the glycerol phosphate in Comparative Example 2 can be combined with wool protein under the catalysis of dicyandiamide, but it only contains one phosphate group and can no longer form insoluble phosphosilicate complex salts with sodium silicate and silicic acid, resulting in sodium silicate and silicic acid only combining with wool protein through weak interactions such as ionic bonds, with poor binding fastness, resulting in less silicon-containing substances on the coated nylon 6 fabric, and ultimately causing the flame retardant properties of the flame retardant nylon 6 fabric to deteriorate.

[0065] Example 2

[0066] A method for flame retardant finishing of nylon 6 fabric using waste wool solution, the specific steps are as follows:

[0067] (1) Raw material preparation:

[0068] waste wool;

[0069] Aminotrimethylenephosphonic acid;

[0070] Dicyandiamide;

[0071] water;

[0072] Sodium silicate solution: the solvent is water;

[0073] ammonia;

[0074] Nylon 6 fabric: Limiting oxygen index is 20.1%, damage length is 30cm, and carbon residue after calcination at 700℃ is 0%;

[0075] (2) Preparation of waste wool solution:

[0076] (2.1) Immerse the waste wool in a mixed aqueous solution of aminotrimethylenephosphonic acid and dicyandiamide, adjust the pH value of the system to 7.5 with ammonia water, and treat at 58°C for 18 minutes;

[0077] Wherein, in the mixed aqueous solution of aminotrimethylenephosphonic acid and dicyandiamide, the concentration of aminotrimethylenephosphonic acid is 80 g / L, and the concentration of dicyandiamide is 34 g / L; the mass ratio of the waste wool to the mixed aqueous solution of aminotrimethylenephosphonic acid and dicyandiamide is 1:25;

[0078] (2.2) immersing the waste wool treated in step (2.1) in a sodium silicate solution at 86° C. for 70 minutes to obtain a waste wool solution;

[0079] The concentration of the sodium silicate solution is 25 g / L, and the mass ratio of waste wool to the sodium silicate solution is 1:35;

[0080] (3) Flame retardant finishing of nylon 6 fabric:

[0081] The nylon 6 fabric was immersed in waste wool solution and treated at 83°C for 65 minutes, and then dried to obtain the flame retardant nylon 6 fabric.

[0082] Among them, the mass ratio of nylon 6 fabric to waste wool solution is 1:35.

[0083] The final flame-retardant nylon 6 fabric had a limiting oxygen index of 30.7%, a damaged length of 9.4 cm, no molten droplets, and a carbon residue of 20.6% after calcination at 700°C.

[0084] Example 3

[0085] A method for flame retardant finishing of nylon 6 fabric using waste wool solution, the specific steps are as follows:

[0086] (1) Raw material preparation:

[0087] waste wool;

[0088] Aminotrimethylenephosphonic acid;

[0089] Dicyandiamide;

[0090] water;

[0091] Sodium silicate solution: the solvent is water;

[0092] ammonia;

[0093] Nylon 6 fabric: Limiting oxygen index is 20.1%, damage length is 30cm, and carbon residue after calcination at 700℃ is 0%;

[0094] (2) Preparation of waste wool solution:

[0095] (2.1) Immerse the waste wool in a mixed aqueous solution of aminotrimethylenephosphonic acid and dicyandiamide, adjust the pH value of the system to 7.5 with ammonia water, and treat at 61°C for 14 minutes;

[0096] Wherein, in the mixed aqueous solution of aminotrimethylenephosphonic acid and dicyandiamide, the concentration of aminotrimethylenephosphonic acid is 90 g / L, and the concentration of dicyandiamide is 37 g / L; the mass ratio of the waste wool to the mixed aqueous solution of aminotrimethylenephosphonic acid and dicyandiamide is 1:25;

[0097] (2.2) immersing the waste wool treated in step (2.1) in a sodium silicate solution at 88° C. for 75 minutes to obtain a waste wool solution;

[0098] The concentration of the sodium silicate solution is 30 g / L, and the mass ratio of waste wool to the sodium silicate solution is 1:40;

[0099] (3) Flame retardant finishing of nylon 6 fabric:

[0100] The nylon 6 fabric was immersed in waste wool solution and treated at 86°C for 60 minutes, and then dried to obtain the flame retardant nylon 6 fabric.

[0101] Among them, the mass ratio of nylon 6 fabric to waste wool solution is 1:40.

[0102] The final flame-retardant nylon 6 fabric had a limiting oxygen index of 31.4%, a damaged length of 9 cm, no molten droplets, and a carbon residue of 21.5% after calcination at 700°C.

[0103] Example 4

[0104] A method for flame retardant finishing of nylon 6 fabric using waste wool solution, the specific steps are as follows:

[0105] (1) Raw material preparation:

[0106] waste wool;

[0107] Aminotrimethylenephosphonic acid;

[0108] Dicyandiamide;

[0109] water;

[0110] Sodium silicate solution: the solvent is water;

[0111] ammonia;

[0112] Nylon 6 fabric: Limiting oxygen index is 20.1%, damage length is 30cm, and carbon residue after calcination at 700℃ is 0%;

[0113] (2) Preparation of waste wool solution:

[0114] (2.1) Immerse the waste wool in a mixed aqueous solution of aminotrimethylenephosphonic acid and dicyandiamide, adjust the pH value of the system to 8 with ammonia water, and treat at 65°C for 10 minutes;

[0115] Wherein, in the mixed aqueous solution of aminotrimethylenephosphonic acid and dicyandiamide, the concentration of aminotrimethylenephosphonic acid is 100 g / L, and the concentration of dicyandiamide is 40 g / L; the mass ratio of the waste wool to the mixed aqueous solution of aminotrimethylenephosphonic acid and dicyandiamide is 1:30;

[0116] (2.2) immersing the waste wool treated in step (2.1) in a sodium silicate solution at 90° C. for 60 minutes to obtain a waste wool solution;

[0117] The concentration of the sodium silicate solution is 40 g / L, and the mass ratio of waste wool to the sodium silicate solution is 1:30;

[0118] (3) Flame retardant finishing of nylon 6 fabric:

[0119] The nylon 6 fabric is immersed in waste wool solution and treated at 90°C for 50 minutes, and then dried to obtain a flame retardant nylon 6 fabric;

[0120] Among them, the mass ratio of nylon 6 fabric to waste wool solution is 1:30.

[0121] The final flame-retardant nylon 6 fabric had a limiting oxygen index of 32%, a damaged length of 8.7 cm, no molten droplets, and a carbon residue of 22.1% after calcination at 700°C.

Claims

1. A method for flame retardant finishing of nylon 6 fabric using waste wool solution, characterized in that: The following steps are involved: (1) soaking the waste wool in a mixed aqueous solution containing aminotrimethylenephosphonic acid and dicyandiamide, adjusting the pH value of the system to 7-8 with ammonia water, and treating at a temperature above 55°C; (2) immersing the waste wool treated in step (1) in a sodium silicate solution at a temperature above 85° C. to obtain a waste wool solution; (3) The nylon 6 fabric is immersed in a waste wool solution at a mass ratio of 1:30-40 and treated at 80-90° C. for 50-70 min, and then dried to obtain a flame retardant nylon 6 fabric.

2. The method for flame retardant finishing of nylon 6 fabric with waste wool solution according to claim 1, characterized in that: In step (1), in the solution containing both aminotrimethylenephosphonic acid and dicyandiamide, the concentration of aminotrimethylenephosphonic acid is 70-100 g / L, and the concentration of dicyandiamide is 30-40 g / L; the mass ratio of the waste wool to the solution containing both aminotrimethylenephosphonic acid and dicyandiamide is 1:20-30.

3. The method for flame retardant finishing of nylon 6 fabric with waste wool solution according to claim 2, characterized in that: In step (1), the treatment temperature is 55 to 65° C. and the treatment time is 10 to 20 minutes.

4. The method for flame retardant finishing of nylon 6 fabric with waste wool solution according to claim 1, characterized in that: In step (2), the concentration of the sodium silicate solution is 20-40 g / L, and the mass ratio of the waste wool to the sodium silicate solution is 1:30-40.

5. The method for flame retardant finishing of nylon 6 fabric with waste wool solution according to claim 4, characterized in that: In step (2), the treatment temperature is 85 to 90° C. and the treatment time is 60 to 90 min.

6. The method for flame retardant finishing of nylon 6 fabric with waste wool solution according to any one of claims 1 to 5, characterized in that: The limiting oxygen index of the flame retardant nylon 6 fabric is ≥29.8%, the damaged length is ≤10.1cm, no molten droplets are generated, and the residual carbon content after calcination at 700℃ is ≥19.4%.

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