A dyeing method for high-density nylon woven fabric

Abstract

The invention relates to the technical field of nylon fabric dyeing methods, and discloses a dyeing method for high-density nylon woven fabrics, comprising the following steps: immersing the high-density nylon woven fabrics in an acidic dye solution for dyeing, adjusting the pH to 3.5-5, and adopting staged heat preservation treatment, sequentially heat preservation at 70-80°C for 10-20min, heat preservation at 90-100°C for 20-30min, and heat preservation at 110-120°C for 45-55min. The staged heat preservation treatment of the acid dye in the invention is conducive to the leveling and covering of the dye, which not only improves the color rate of the dye, but also improves the color fastness; the step-by-step temperature increase is adopted to ensure the uniformity of dyeing, and avoid the occurrence of color flower, color willow and other dyeing problems; a high dye amount of nylon fiber is obtained by adopting a low bath ratio, and the higher the dye amount on the nylon fiber, the better the coloring rate of the fabric.

Description

Technical Field

[0001] The present invention relates to the technical field of nylon fabric dyeing methods, and in particular to a dyeing method for high-density nylon woven fabrics. Background Art

[0002] Currently, there are a wide variety of luggage on the market, including genuine leather and PU. However, the styles of genuine leather luggage are relatively single, and the later maintenance is quite troublesome. Moreover, it depends on animal sources, is expensive, and the animal skin treatment process is relatively complex. PU luggage is generally obtained by using coated fabrics or laminated fabrics, but these fabrics are relatively thick, and there may be problems with poor peeling performance between the fabric and the resin film layer. In addition, the use of a large amount of chemicals during the processing is not conducive to environmental protection.

[0003] Therefore, considering from the perspective of environmental protection and practical factors such as wear resistance, tear resistance, light weight, waterproofness, and color change resistance, nylon fibers are more suitable for luggage use. Nylon fibers have good mechanical properties, heat resistance, abrasion resistance, flame retardancy, chemical resistance, etc. Luggage made of woven fabrics woven from nylon fibers is very popular among consumers. However, there are problems with coloring of high-density nylon luggage fabrics, and it is difficult to meet the qualified durability color fastness after coloring. Moreover, in the traditional dyeing production process, there are problems such as large consumption of water and steam, low production efficiency, and high scrap rate. Chinese invention patent with publication number CN111996808A discloses a production process for lightweight and high-strength luggage nylon fabrics, including the following steps: S1, preparation of the surface fabric, the surface fabric uses 20D nylon ultra-light fabric, warp yarn 40D / 24F, warp density 180T, weft yarn 40D / 24F, weft density 120T; S2, desizing the surface fabric; S3, dyeing the surface fabric to form a colored fabric; S4, performing water setting on the dyed colored fabric; S5, calendering the front side of the colored fabric; S6, coating the first layer on the surface fabric; S7, coating the second layer on the surface fabric, specifically, after the fabric passes through the first layer, the second layer is coated on its front side. The process of dyeing the surface fabric to form a colored fabric does not improve the coloring problem of nylon fabrics, and there are still problems of uneven coloring and poor durability color fastness. Summary of the Invention

[0004] In order to solve the problems of uneven coloring and poor durability color fastness of high-density nylon woven fabrics, the present invention provides a dyeing method for high-density nylon woven fabrics. By optimizing the dyeing heat preservation treatment process, the dyed nylon fabrics simultaneously have the excellent characteristics of high coloring rate and high color fastness, and can also save energy and reduce consumption.

[0005] The specific technical solution of the present invention is as follows: The present invention provides a dyeing method for high-density nylon woven fabric, which includes the following steps: Immerse the high-density nylon woven fabric in an acidic dye solution for dyeing, adjust the pH to 3.5 - 5, and adopt stagewise heat preservation treatment, successively keep warm at 70 - 80 °C for 10 - 20 min, at 90 - 100 °C for 20 - 30 min, and at 110 - 120 °C for 45 - 55 min.

[0006] Because the simpler the molecular structure of the acidic dye and the smaller the relative molecular mass, the larger the proportion of water-soluble groups it contains, and the better its level dyeing property. During the dyeing process, on the one hand, through the treatment of nylon fibers at high temperature, the macromolecular chain segments move around, and the tiny cavities inside the fibers merge into larger cavities, so that the dye molecules penetrate into the nylon fibers along these constantly changing cavities, strengthening the binding between the dye molecules and the terminal amino groups of the nylon fibers. Coupled with the stagewise heat preservation treatment, the dye obtains a certain migration property, which helps the level dyeing and covering dyeing of the dye, not only improving the color yield of the dye, but also improving the dyeing fastness, thus improving the color yield of the dye and the dyeing fastness.

[0007] In addition, in order to obtain a better coloring rate, the dyeing conditions used are also particularly important. Because under the condition of a certain temperature, the dye adsorption amount decreases significantly with the increase of the pH value of the dye solution, but if the pH value is too low, the amide groups of the fiber are prone to adsorb H + protons to form -NH 3+ with a positive charge, and there may be a problem of over-equivalent adsorption, resulting in the degradation of nylon fibers. Therefore, controlling the pH value of the dye solution at 3.5 - 5 can ensure the adsorption amount of the fabric to the dye solution.

[0008] Preferably, the gram weight of the high-density nylon woven fabric is 300 - 400 g / m 2 .

[0009] Preferably, the acidic dye solution includes an acidic dye and acetic acid.

[0010] Preferably, the bath ratio during dyeing is 1:4 - 6.

[0011] By adopting a low bath ratio, a high dye amount on nylon fibers can be obtained. The higher the dye amount on nylon fibers, the better the coloring rate of the fabric.

[0012] Preferably, the dyeing also adopts stepwise heating; the stepwise heating is as follows: heating from room temperature to 60°C at a rate of 2 - 3°C / min, heating from 60°C to 70 - 80°C at a rate of 1 - 1.5°C / min and holding for a certain time, heating from 70 - 80°C to 80 - 100°C at a rate of 1 - 2°C / min and holding for a certain time, heating from 80 - 100°C to 110 - 120°C at a rate of 0.5 - 1.5°C / min and holding for a certain time, and finally cooling from 110 - 120°C to room temperature at a rate of -2 - -1°C / min.

[0013] Nylon fiber belongs to thermoplastic fiber. At low temperature, the dyeing rate is very slow. When the temperature is more than 60% above the glass transition temperature, the fiber will expand rapidly and the dye uptake rate will increase linearly. If the heating rate is too fast at this moment, dyeing problems such as color streaks and color unevenness are likely to occur. Therefore, stepwise heating is adopted to ensure the uniformity of dye uptake.

[0014] Preferably, before the dyeing of the high-density nylon woven fabric, it also includes surface pretreatment of the high-density nylon woven fabric; the surface pretreatment includes the following steps:

[0015] Immerse the high-density nylon woven fabric in the mixed solution I of polyvinyl alcohol and water, keep it at 70 - 90°C for heat treatment for 20 - 50 min, then add epichlorohydrin and lignosulfonate and stir for 10 - 30 min; then take out the fabric and dry it, immerse it in the mixed solution II of glacial acetic acid, citric acid and water, add polydopamine-coated nanoceramic powder and react at 60 - 70°C for 30 - 60 min, and then take out the fabric and dry it again.

[0016] Polyvinyl alcohol on the surface layer of the nylon fabric has good film-forming properties. The hydroxyl groups it contains have good affinity with both the nylon fabric and acid dyes, and can improve the dye uptake rate by van der Waals force and hydrogen bond. The sulfonic acid groups on the added lignosulfonate can gradually reduce the pH value of the dye solution, so that the nylon fiber can gradually release terminal amino groups, which is beneficial to the strong ionic bond binding between acid dyes and polyamide fibers. Crosslinking occurs between polyvinyl alcohol and lignosulfonate through epichlorohydrin to improve the binding stability. In addition, nanoceramic powder can form a rough surface on the surface layer of the nylon fabric, increase the specific surface area to improve the dyeing efficiency, and the nanoceramic powder also has good ultraviolet resistance, which can increase the added value of the nylon fabric and improve the durability. The polydopamine coated on the surface of the nanoceramic powder can provide terminal amino groups to improve the dyeing efficiency, and at the same time can crosslink and bind with the polyvinyl alcohol on the surface of the nylon fabric through citric acid to improve the binding stability of the nanoceramic powder. Therefore, after the surface pretreatment of the high-density nylon woven fabric, the dye uptake rate can be improved, and the dyed fabric has high coloration rate and high color fastness.

[0017] Preferably, the molecular weight of the polyvinyl alcohol is 100,000 to 130,000, and the degree of alcoholysis is 97 to 99%; the concentration of polyvinyl alcohol in the mixed solution I is 10 to 14%; the mass ratio of polyvinyl alcohol, epichlorohydrin and lignosulfonate is 1: 0.05 to 0.1: 0.2 to 0.5; the mass ratio of glacial acetic acid, citric acid, water and nano-ceramic powder coated with polydopamine is 0.1 to 1: 3 to 10: 80 to 120: 1 to 4.

[0018] The molecular weight of polyvinyl alcohol and its concentration in aqueous solution affect the viscosity, which in turn affects the film-forming property. The degree of alcoholysis of polyvinyl alcohol affects its solubility in aqueous solution, which in turn affects the effect of surface pretreatment of the fabric. Under the influence of this degree of alcoholysis and degree of polymerization, the polyvinyl alcohol after film formation is not easily swollen or dissolved during the dyeing process, and a high coloring rate can be achieved. The mass ratio between raw materials determines the cross-linked structure and the binding stability. Under this ratio, the best surface pretreatment effect of the fabric can be achieved.

[0019] Preferably, the preparation method of the nano-ceramic powder coated with polydopamine is: adding nano-ceramic powder into a mixed solution of dopamine hydrochloride, water and ammonia water, adjusting the pH to 8 to 9, and stirring and reacting at 20 to 40 °C for 12 to 20 h, and then sequentially filtering and drying to obtain nano-ceramic powder coated with polydopamine.

[0020] Preferably, the particle size of the nano-ceramic powder is 50 to 100 nm; the mass ratio of the nano-ceramic powder to dopamine hydrochloride is 1 to 2: 1.

[0021] The particle size of the nano-ceramic powder affects the coating property of polydopamine. The binding stability between substances exceeding this range will decrease. More importantly, the particle size affects the degree of roughness of the fabric surface. The smaller the particle size, the weaker the effect of improving the dye coloring rate caused by surface roughness, and the larger the particle size, the dyeing uniformity will be affected, thereby affecting the appearance quality of the fabric.

[0022] Compared with the prior art, the present invention has the following advantages:

[0023] (1) The staged heat preservation treatment of acid dyes gives the dyes a certain migration property, which helps the leveling and covering of dyes, not only improving the coloring rate of the dyes, but also improving the color fastness;

[0024] (2) Stepwise temperature increase is adopted to ensure the uniformity of dyeing, and to avoid dyeing problems such as color streaks and color stripes;

[0025] (3) By adopting a low bath ratio, a high dye amount on nylon fibers can be obtained. The higher the dye amount on nylon fibers, the better the coloring rate of the fabric. Specific embodiments

[0026] The present invention will be further described below in conjunction with embodiments.

[0027] General Embodiment

[0028] A dyeing method for a high-density nylon woven fabric, comprising the following steps: Immerse a high-density nylon woven fabric with a gram weight of 300 - 400 g / m 2 in an acidic dye solution for dyeing, with a bath ratio of 1:4 - 6, adjust the pH to 3.5 - 5, and adopt a segmented heating and staged heat preservation treatment. Heat from room temperature to 60 °C at a rate of 2 - 3 °C / min, heat from 60 °C to 70 - 80 °C at a rate of 1 - 1.5 °C / min and keep warm for 10 - 20 min, heat from 70 - 80 °C to 80 - 100 °C at a rate of 1 - 2 °C / min and keep warm for 20 - 30 min, heat from 80 - 100 °C to 110 - 120 °C at a rate of 0.5 - 1.5 °C / min and keep warm for 45 - 55 min, and finally cool from 110 - 120 °C to room temperature at a rate of -2 - -1 °C / min. Among them, the acidic dye solution includes acid dyes and acetic acid.

[0029] In addition, the surface pretreatment of the high-density nylon woven fabric may also be included before dyeing, including the following steps:

[0030] Prepare a mixed solution Ⅰ with a concentration of 10 - 14% by mixing polyvinyl alcohol with a molecular weight of 100000 - 130000 and a degree of alcoholysis of 97 - 99% and water. Then immerse the high-density nylon woven fabric in the mixed solution Ⅰ and keep it warm at 70 - 90 °C for 20 - 50 min. Then add epichlorohydrin and lignosulfonate and stir for 10 - 30 min. The mass ratio of polyvinyl alcohol, epichlorohydrin, and lignosulfonate is 1:0.05 - 0.1:0.2 - 0.5; then take out the fabric and dry it, and then immerse it in a mixed solution Ⅱ of glacial acetic acid, citric acid, and water. Then add polydopamine-coated nanoceramic powder and react at 60 - 70 °C for 30 - 60 min. The mass ratio of glacial acetic acid, citric acid, water, and polydopamine-coated nanoceramic powder is 0.1 - 1:3 - 10:80 - 120:1 - 4. After that, take out the fabric again and dry it.

[0031] Among them, the preparation method of the polydopamine-coated nanoceramic powder is: Add nanoceramic powder with a particle size of 50 - 100 nm to a mixed solution of dopamine hydrochloride, water, and ammonia water. The mass ratio of nanoceramic powder and dopamine hydrochloride is 1 - 2:1. Adjust the pH to 8 - 9, and stir and react at 20 - 40 °C for 12 - 20 h. Then, after filtration and drying in sequence, the polydopamine-coated nanoceramic powder is obtained.

[0032] Embodiment 1

[0033] A dyeing method for a high-density nylon woven fabric, comprising the following steps: Immerse a high-density nylon woven fabric with a grammage of 350 g / m 2 in an acidic dye bath for dyeing, with a liquor ratio of 1:5, adjust the pH to about 4.3. The acidic dye bath includes Yellow S-GL 0.2% o.w.f, Black 2S-LD 3.0% o.w.f and acetic acid 0.4% o.w.f. Then, carry out a temperature rise and heat preservation treatment as shown in Table 1 below. After the treatment is completed, take out the fabric and dry it.

[0034] Table 1 Temperature rise and heat preservation treatment parameters in Example 1

[0035]

[0036]

[0037] Example 2

[0038] A dyeing method for a high-density nylon woven fabric, comprising the following steps: Immerse a high-density nylon woven fabric with a grammage of 385 g / m 2 in an acidic dye bath for dyeing, with a liquor ratio of 1:5, adjust the pH to about 4.3. The acidic dye bath includes Yellow S-GL 0.2% o.w.f, Black 2S-LD 3.0% o.w.f and acetic acid 0.4% o.w.f. Then, carry out a temperature rise and heat preservation treatment as shown in Table 2 below. After the treatment is completed, take out the fabric and dry it.

[0039] Table 2 Temperature rise and heat preservation treatment parameters in Example 2

[0040] Segmented temperature Temperature change rate Insulation temperature * time Room temperature - 60°C 2°C / min / 60℃—80℃ 1°C / min 80°C * 15 min 80℃—100℃ 1.5°C / min 100°C * 30 min 100℃—120℃ 1°C / min 120°C * 50 min 120°C - Room temperature -1°C / min /

[0041] Example 3

[0042] A dyeing method for a high-density nylon woven fabric, comprising the following steps: Immerse a high-density nylon woven fabric with a grammage of 350 g / m 2 in an acidic dye bath for dyeing, with a liquor ratio of 1:6, adjust the pH to about 3.8. The acidic dye bath includes Yellow S-GL 0.2% o.w.f, Black 2S-LD 3.0% o.w.f and acetic acid 0.4% o.w.f. Then, carry out a temperature rise and heat preservation treatment as shown in Table 3 below. After the treatment is completed, take out the fabric and dry it.

[0043] Table 3 Temperature rise and heat preservation treatment parameters in Example 3

[0044] Segmented temperature Temperature change rate Insulation temperature * time Room temperature - 60°C 2°C / min / 60℃—75℃ 1.5°C / min 75°C * 15 min 75℃—95℃ 1°C / min 95°C * 25 min 95℃—120℃ 0.5°C / min 120°C * 45 min 120°C - Room temperature -2°C / min /

[0045] Example 4

[0046] The difference from Example 1 is that it further includes a pretreatment step for the fabric surface.

[0047] A dyeing method for a high-density nylon woven fabric includes the following steps:

[0048] Prepare a mixed solution I with a concentration of 12% by mixing polyvinyl alcohol with a molecular weight of 110,000 and a degree of alcoholysis of 98% and water. Then, immerse a high-density nylon woven fabric with a grammage of 350 g / m 2 in the mixed solution I and keep it at 85°C for 30 minutes. Then, add epichlorohydrin and lignosulfonate and stir for 15 minutes. The mass ratio of polyvinyl alcohol, epichlorohydrin, and lignosulfonate is 1:0.07:0.3. Then, take out the fabric and dry it, and then immerse it in a mixed solution II of glacial acetic acid, citric acid, and water. Then, add polydopamine-coated nanoceramic powder and react at 70°C for 35 minutes. The mass ratio of glacial acetic acid, citric acid, water, and polydopamine-coated nanoceramic powder is 0.2:5:100:2. After that, take out the fabric again and dry it.

[0049] Among them, the preparation method of the polydopamine-coated nanoceramic powder is: add nanoceramic powder with an average particle size of 60 nm to a mixed solution of dopamine hydrochloride, water, and ammonia water. The mass ratio of nanoceramic powder, dopamine hydrochloride, and water is 1.5:1:100. Adjust the pH to 8-9 with ammonia water, and then stir and react at 30°C for 18 hours. Then, filter and dry it in sequence to obtain the polydopamine-coated nanoceramic powder.

[0050] Then, immerse the pretreated high-density nylon woven fabric described above in an acidic dye solution for dyeing. The bath ratio is 1:5, and adjust the pH to about 4.3. The acidic dye solution includes 0.2% o.w.f of Yellow S-GL, 3.0% o.w.f of Black 2S-LD, and 0.4% o.w.f of acetic acid. Then, perform a temperature-raising and heat-preserving treatment according to Table 1. After the treatment is completed, take out the fabric and dry it.

[0051] Example 5

[0052] The difference from Example 1 is that it further includes a pretreatment step for the fabric surface.

[0053] A dyeing method for a high-density nylon woven fabric includes the following steps:

[0054] Prepare a mixed solution I with a concentration of 12% by mixing polyvinyl alcohol with a molecular weight of 130,000 and a degree of alcoholysis of 98% and water. Then, immerse a high-density nylon woven fabric with a grammage of 350 g / m 2A high-density nylon woven fabric is immersed in mixed solution I and heat-treated at 75 °C for 40 min. Then, epichlorohydrin and lignosulfonate are added and stirred for 30 min. The mass ratio of polyvinyl alcohol, epichlorohydrin, and lignosulfonate is 1:0.09:0.5. Subsequently, the fabric is taken out and dried, then immersed in a mixed solution II of glacial acetic acid, citric acid, and water. After adding nano-ceramic powder coated with polydopamine, the reaction is carried out at 60 °C for 45 min. The mass ratio of glacial acetic acid, citric acid, water, and nano-ceramic powder coated with polydopamine is 0.4:4:100:2. Then, the fabric is taken out again and dried.

[0055] Among them, the preparation method of the nano-ceramic powder coated with polydopamine is as follows: Nano-ceramic powder with an average particle size of 75 nm is added to a mixed solution of dopamine hydrochloride, water, and ammonia water. The mass ratio of nano-ceramic powder, dopamine hydrochloride, and water is 1:1:100. The pH is adjusted to 8-9 with ammonia water, and then stirred and reacted at 20 °C for 20 h. After that, it is successively filtered and dried to obtain the nano-ceramic powder coated with polydopamine.

[0056] Next, the surface-pretreated high-density nylon woven fabric is immersed in an acidic dye solution for dyeing. The bath ratio is 1:5, and the pH is adjusted to about 4.3. The acidic dye solution includes 0.2% o.w.f of Yellow S-GL, 3.0% o.w.f of Black 2S-LD, and 0.4% o.w.f of acetic acid. Then, the temperature is raised and heat-treated according to Table 1. After the treatment is completed, the fabric is taken out and dried.

[0057] Comparative Example 1

[0058] The difference from Example 4 is that no nano-ceramic powder is added.

[0059] A dyeing method for a high-density nylon woven fabric includes the following steps:

[0060] Polyvinyl alcohol with a molecular weight of 110,000 and a degree of alcoholysis of 98% and water are configured into a mixed solution I with a concentration of 12%. Then, a high-density nylon woven fabric with a gram weight of 350 g / m 2 is immersed in the mixed solution I and heat-treated at 85 °C for 30 min. Then, epichlorohydrin and lignosulfonate are added and stirred for 15 min. The mass ratio of polyvinyl alcohol, epichlorohydrin, and lignosulfonate is 1:0.07:0.3. Then, the fabric is taken out and dried.

[0061] Next, immerse the pretreated high-density nylon woven fabric on the surface in an acidic dye solution for dyeing. The bath ratio is 1:5, and the pH is adjusted to about 4.3. The acidic dye solution includes 0.2% o.w.f of Yellow S-GL, 3.0% o.w.f of Black 2S-LD, and 0.4% o.w.f of acetic acid. Then, carry out temperature-raising and heat-preserving treatment as shown in Table 1. After the treatment is completed, take out the fabric and dry it.

[0062] Comparative Example 2

[0063] The difference from Example 4 is that the molecular weight of the added polyvinyl alcohol is 200,000.

[0064] A dyeing method for high-density nylon woven fabric, comprising the following steps:

[0065] Prepare a mixed solution I with a concentration of 12% by mixing polyvinyl alcohol with a molecular weight of 200,000 and a degree of alcoholysis of 98% and water. Then, immerse the high-density nylon woven fabric with a gram weight of 350 g / m 2 in the mixed solution I and carry out heat-preserving treatment at 85°C for 30 min. Then, add epichlorohydrin and lignosulfonate and stir for 15 min. The mass ratio of polyvinyl alcohol, epichlorohydrin, and lignosulfonate is 1:0.07:0.3. Then, take out the fabric and dry it. After that, immerse it in a mixed solution II of glacial acetic acid, citric acid, and water. Then, add poly-dopamine-coated nano-ceramic powder and react at 70°C for 35 min. The mass ratio of glacial acetic acid, citric acid, water, and poly-dopamine-coated nano-ceramic powder is 0.2:5:100:2. Then, take out the fabric again and dry it.

[0066] Among them, the preparation method of the poly-dopamine-coated nano-ceramic powder is as follows: Add nano-ceramic powder with an average particle size of 60 nm to a mixed solution of dopamine hydrochloride, water, and ammonia water. The mass ratio of nano-ceramic powder, dopamine hydrochloride, and water is 1.5:1:100. Adjust the pH to 8-9 with ammonia water, and then stir and react at 30°C for 18 h. Then, obtain the poly-dopamine-coated nano-ceramic powder through filtration and drying in sequence.

[0067] Next, immerse the pretreated high-density nylon woven fabric on the surface in an acidic dye solution for dyeing. The bath ratio is 1:5, and the pH is adjusted to about 4.3. The acidic dye solution includes 0.2% o.w.f of Yellow S-GL, 3.0% o.w.f of Black 2S-LD, and 0.4% o.w.f of acetic acid. Then, carry out temperature-raising and heat-preserving treatment as shown in Table 1. After the treatment is completed, take out the fabric and dry it.

[0068] Comparative Example 3

[0069] The difference from Example 4 is that the degree of alcoholysis of the added polyvinyl alcohol is 88%.

[0070] A dyeing method for a high-density nylon woven fabric, comprising the following steps:

[0071] Prepare a mixed solution I with a concentration of 12% from polyvinyl alcohol with a molecular weight of 110,000 and a degree of alcoholysis of 88% and water. Then immerse the high-density nylon woven fabric with a grammage of 350 g / m 2 in the mixed solution I and keep it at 85 °C for 30 min. Then add epichlorohydrin and lignosulfonate and stir for 15 min. The mass ratio of polyvinyl alcohol, epichlorohydrin and lignosulfonate is 1:0.07:0.3. Then take out the fabric and dry it, and immerse it in a mixed solution II of glacial acetic acid, citric acid and water. Then add polydopamine-coated nanoceramic powder and react at 70 °C for 35 min. The mass ratio of glacial acetic acid, citric acid, water and polydopamine-coated nanoceramic powder is 0.2:5:100:2. Then take out the fabric again and dry it.

[0072] Among them, the preparation method of the polydopamine-coated nanoceramic powder is as follows: Add nanoceramic powder with an average particle size of 60 nm to a mixed solution of dopamine hydrochloride, water and ammonia water. The mass ratio of nanoceramic powder, dopamine hydrochloride and water is 1.5:1:100. Adjust the pH to 8-9 with ammonia water, and then stir and react at 30 °C for 18 h. Then filter and dry in turn to obtain the polydopamine-coated nanoceramic powder.

[0073] Then, immerse the surface-pretreated high-density nylon woven fabric in an acidic dye solution for dyeing. The bath ratio is 1:5, and adjust the pH to about 4.3. The acidic dye solution includes 0.2% o.w.f of Yellow S-GL, 3.0% o.w.f of Black 2S-LD and 0.4% o.w.f of acetic acid. Then carry out temperature-rising and heat-preserving treatment according to Table 1. After the treatment is completed, take out the fabric and dry it.

[0074] Comparative Example 4

[0075] The difference from Example 4 is that the particle size of the nanoceramic powder is 300 nm.

[0076] A dyeing method for a high-density nylon woven fabric, comprising the following steps:

[0077] Prepare a mixed solution I with a concentration of 12% from polyvinyl alcohol with a molecular weight of 110,000 and a degree of alcoholysis of 98% and water. Then immerse the high-density nylon woven fabric with a grammage of 350 g / m 2The high-density nylon woven fabric is immersed in the mixed solution I and heat-treated at 85 °C for 30 min. Then, epichlorohydrin and lignosulfonate are added and stirred for 15 min. The mass ratio of polyvinyl alcohol, epichlorohydrin, and lignosulfonate is 1:0.07:0.3. Then, the fabric is taken out and dried, and then immersed in the mixed solution II of glacial acetic acid, citric acid, and water. Then, polydopamine-coated nanoceramic powder is added and reacted at 70 °C for 35 min. The mass ratio of glacial acetic acid, citric acid, water, and polydopamine-coated nanoceramic powder is 0.2:5:100:2. After that, the fabric is taken out again and dried.

[0078] Among them, the preparation method of the polydopamine-coated nanoceramic powder is as follows: The nanoceramic powder with an average particle size of 300 nm is added to the mixed solution of dopamine hydrochloride, water, and ammonia water. The mass ratio of the nanoceramic powder, dopamine hydrochloride, and water is 1.5:1:100. The pH is adjusted to 8-9 with ammonia water, and then stirred and reacted at 30 °C for 18 h. Then, it is filtered and dried in turn to obtain the polydopamine-coated nanoceramic powder.

[0079] Next, the surface-pretreated high-density nylon woven fabric is immersed in the acidic dye liquor for dyeing. The bath ratio is 1:5, and the pH is adjusted to about 4.3. The acidic dye liquor includes 0.2% o.w.f of Yellow S-GL, 3.0% o.w.f of Black 2S-LD, and 0.4% o.w.f of acetic acid. Then, the temperature is raised and kept warm according to Table 1. After the treatment is completed, the fabric is taken out and dried.

[0080] Performance testing

[0081] Color fastness to rubbing: Tested in accordance with the standard GB / T 3920-1997;

[0082] Dye uptake: Measured on a 723-type spectrophotometer by the residual liquor method, and the dye uptake at time T is calculated: Dye uptake E = [(A 0 - A T ) / A 0 × 100%; In the formula: A 0 is the absorbance of the original solution; A T is the absorbance of the dyeing residual liquor at time T;

[0083] Average UV transmittance: Test the average transmittance of the high-density nylon woven fabric at the UV wavelength of 280-400 nm.

[0084] Table 4 Dyeing properties of each group of high-density nylon woven fabrics

[0085]

[0086] As shown in Table 1, the dyeing method in the present invention can obtain nylon fabrics with a high dye uptake rate, ensure the uniformity of dyeing, avoid dyeing problems such as color streaks and color bars, and also improve the rubbing fastness. In addition, in combination with Examples 1-5, the surface pretreatment of the fabric can further improve the dye coloring rate and fastness, which is mainly achieved by increasing the specific surface area of dyeing and the functional groups of interaction. In combination with Example 4 and Comparative Example 1, after the nano-ceramic powder is not added, the dyeing is only carried out by the interaction of the hydroxyl groups, sulfonic acid groups on the fabric surface, the terminal amino groups of nylon fibers and the dye molecules, reducing the dye uptake rate and the anti-ultraviolet additional value. In combination with Example 4 and Comparative Examples 2-3, if the molecular weight of polyvinyl alcohol is too large, the viscosity will be too large, which will affect the film-forming property and the loading effect of nano-ceramic powder, and both the dye uptake rate and the fastness will be reduced; while polyvinyl alcohol with a lower degree of alcoholysis is easy to dissolve and is liable to occur the phenomenon of unstable combination during the dyeing process, reducing the dye uptake rate. In combination with Example 4 and Comparative Example 4, the particle size of the nano-ceramic powder will affect the coating property of polydopamine, and the binding stability between substances exceeding this range will decrease. More importantly, the particle size will affect the roughness of the fabric surface. The larger the particle size, the more the dyeing uniformity and fastness will be affected.

[0087] The above are only the preferred embodiments of the present invention, and do not impose any limitations on the present invention. Any simple modifications, changes and equivalent transformations made to the above embodiments according to the technical essence of the present invention still belong to the protection scope of the technical solution of the present invention.

Claims

1. A method for dyeing high-density nylon woven fabrics, characterized in that: The steps include: The high-density nylon woven fabric is immersed in a mixture of polyvinyl alcohol and water, wherein the molecular weight of the polyvinyl alcohol is 100000-130000 and the degree of alcoholysis is 97-99%, and the mixture is kept at 70-90°C for 20-50 minutes, and epichlorohydrin and lignin sulfonate are added and stirred, and the mass ratio of polyvinyl alcohol, epichlorohydrin and lignin sulfonate is 1:0.05-0.1:0.2-0.5; the fabric is taken out, dried, and immersed in a mixture of glacial acetic acid, citric acid and water, and nano-ceramic powder coated with polydopamine is added, and the mixture is reacted at 60-70°C for 30-60 minutes, and the mass ratio of glacial acetic acid, citric acid, water and nano-ceramic powder coated with polydopamine is 0.1-1:3-10:80-120:1-4, and the particle size of the nano-ceramic powder is 50-100 nm; the fabric is taken out and dried; Immerse the dried fabric in acid dye solution for dyeing, adjust the pH to 3.5~5, and use staged heat preservation, keep warm at 70~80℃ for 10~20min, 90~100℃ for 20~30min, and 110~120℃ for 45~55min.

2. The method for dyeing high-density nylon woven fabric according to claim 1, characterized in that: The high-density nylon woven fabric has a gram weight of 300-400 g / m 2 .

3. The dyeing method of high-density nylon woven fabric according to claim 1, characterized in that: The acidic dye solution comprises an acidic dye and acetic acid.

4. The dyeing method of high-density nylon woven fabric according to claim 1, characterized in that: The bath ratio during dyeing is 1:4-6.

5. The method for dyeing high-density nylon woven fabric according to any one of claims 1 to 4, characterized in that: The dyeing process also adopts a stepwise heating method; the stepwise heating method is as follows: heating from room temperature to 60°C at a rate of 2-3°C / min, then heating to 70-80°C at a rate of 1-1.5°C / min and keeping the temperature, then heating to 80-100°C at a rate of 1-2°C / min and keeping the temperature, then heating to 110-120°C at a rate of 0.5-1.5°C / min and keeping the temperature, and finally cooling to room temperature at a rate of -2--1°C / min.

6. The method for dyeing high-density nylon woven fabrics as claimed in claim 1, characterized in that: The concentration of polyvinyl alcohol in the mixture of polyvinyl alcohol and water is 10-14%.

7. The method for dyeing high-density nylon woven fabrics as claimed in claim 1, characterized in that: The stirring time for adding epichlorohydrin and lignin sulfonate is 10 to 30 minutes.

8. The method for dyeing high-density nylon woven fabrics as claimed in claim 1, characterized in that: The preparation method of the polydopamine-coated nano-ceramic powder is as follows: adding the nano-ceramic powder to a mixed solution of dopamine hydrochloride, water and ammonia water, adjusting the pH to 8-9, and stirring the reaction at 20-40° C. for 12-20 hours, and then filtering and drying in sequence to obtain the polydopamine-coated nano-ceramic powder.

9. The method for dyeing high-density nylon woven fabrics as claimed in claim 8, characterized in that: The mass ratio of the nano ceramic powder to dopamine hydrochloride is 1-2:1.

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