Ionic liquid-based carrier and dyeing method of ionic liquid-based carrier on jean fabric

Abstract

The ionic liquid-based carrier adopts PEG400 which can better wrap indigo particles, an amphiphilic structure of a sulfonic acid group type acrylate penetrant can better reduce the surface tension of the ionic liquid-based carrier and break through a low-temperature permeation energy barrier, and nano silicon dioxide destroys a crystal growth point and forms a hydrogen bond network with sulfonic acid groups in the acrylate penetrant, so that the ionic liquid-based carrier has the advantages that the surface tension of the ionic liquid-based carrier is reduced; according to the dyeing method disclosed by the invention, the ionic liquid-based carrier is combined, the fibers of the jean fabric are wetted and chambered in an initial permeation stage, and then the deep permeation is carried out through gradient heating and pressurizing in a reinforced permeation stage, so that the permeation depth of the indigo aggregate in the jean fabric is increased.

Description

Technical Field

[0001] This invention relates to the field of textile materials, and more particularly to an ionic liquid-based carrier and its dyeing method for denim fabrics. Background Technology

[0002] The denim dyeing industry has long faced a technical bottleneck due to insufficient penetration depth. While traditional organic carriers (such as o-dichlorobenzene and benzyl alcohol) can enhance the apparent color yield of indigo, their large molecular size (≥1.5nm) and low compatibility with cellulose fibers limit their penetration depth in the dense structure of denim to within 80μm (AATCC 179-2012 standard cross-section test, industry average 78±5μm). This results in a significant "white core" in the fabric cross-section, affecting the color fastness and physical properties of the finished product. More seriously, these carriers require high-temperature processes at 85-95℃, consuming as much as 1.6-1.8kWh / kg of energy and releasing large amounts of volatile organic compounds (VOCs). Their ecotoxicity (zebrafish 96h-LC50 of only 8.5mg / L) far exceeds the EU REACH regulation limit (100mg / L).

[0003] To overcome the permeation limitations, ionic liquids (such as 1-butyl-3-methylimidazolium tetrafluoroborate, [BMIM]BF4) have been extensively studied due to their cationic structure's ability to swell the amorphous regions of fibers. However, their industrial application faces two major obstacles: first, at low temperatures, their diffusion coefficient is only 2.1 × 10⁻¹⁰ m² / s, making it difficult to drive deep permeation of indigo aggregates, resulting in kinetic defects; second, [BMIM]BF4 exhibits thermal instability: at temperatures > 76.5 °C, BF4... - The anion hydrolysis rate increased exponentially, and the inactivation rate was >22% after treatment at 80℃ for 30 min.

[0004] While single ionic liquid carriers require high-temperature operation (80°C) for penetration, this leads to irreversible decomposition of the ionic liquid, severely limiting the deep penetration of indigo aggregates into denim fabrics. Therefore, there is an urgent need for an ionic liquid-based carrier that can achieve deep penetration of indigo into denim fabrics and a dyeing method for denim fabrics. Summary of the Invention

[0005] The objective of this invention is achieved through the following technical solution: An ionic liquid-based support comprises the following components in parts by mass: [BMIM]BF4 60-70 servings; PEG400 20-25 parts; 5-8 parts of sulfonic acid-based acrylate penetrant; 1-3 parts of nano-silica; 5-10 parts deionized water.

[0006] Preferably, the sulfonic acid-based acrylate penetrant is BASF MA-80.

[0007] Preferably, the mass ratio of [BMIM]BF4, PEG400, BASF MA-80, nano silica and deionized water is 65:22:7:1:5.

[0008] This invention also provides a method for dyeing denim fabrics with an ionic liquid-based carrier, comprising the following steps: S1. Mix the ionic liquid-based carrier, indigo particles and sodium alginate thickener in a mass ratio of 38:30:32 to obtain the dye agent. The particle size of the indigo particles is less than or equal to 0.5 μm. S2. Apply the dye to the base film to form a transfer film; S3. Apply the transfer film to the denim fabric and roll the transfer film at a temperature of 50℃ and a pressure of 0.15MPa for 60 seconds to allow it to initially penetrate. S4. After initial penetration at a temperature of 55℃ and a pressure of 0.28Mpa, the transfer film is subjected to enhanced penetration for 30 seconds. S5. Fix the color of the coated area after enhanced penetration, and then recover the residual material on the transfer film.

[0009] Preferably, the initial infiltration humidity is 90%, and the enhanced infiltration humidity is 95%.

[0010] The dyeing process is carried out in a high-humidity environment to avoid damage to the denim fibers. A 90%-95% gradient humidity increase is used to prevent condensation on the denim surface, which would affect the dyeing effect.

[0011] Preferably, the coating speed in step S2 is 18 m / min and the coating temperature is 45°C.

[0012] Preferably, in step S5, the denim fabric transfer area is steamed with 100°C saturated steam for 90 seconds.

[0013] Preferably, in step S5, the residual material on the transfer film is scraped off and extracted for 40 min at 32.5 MPa and 45 °C using a supercritical CO2 extraction method.

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows: The ionic liquid-based carrier of this invention uses PEG400, which can effectively encapsulate indigo particles. The sulfonic acid groups of MA-80 provide excellent hydrophilicity and affinity for fibers, effectively reducing the surface tension of the ionic liquid-based carrier, balancing surface tension and forming stable micelles, thus overcoming the low-temperature penetration barrier. Nano-silica disrupts crystal growth points and forms a hydrogen bond network with the sulfonic acid groups in the acrylate penetrant, facilitating the deep penetration of indigo aggregates into denim fabrics. The dyeing method of this invention, combined with the ionic liquid-based carrier, wets and expands the pores of denim fabric fibers in the initial penetration stage, and then performs deep penetration through a gradient temperature and pressure enhancement stage, thereby increasing the penetration depth of indigo aggregates in denim fabrics. Detailed Implementation

[0015] To make the technical problems solved by this invention, the technical solutions adopted, and the technical effects achieved clearer, the technical solutions of the embodiments of this invention will be described in further detail below. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention. Example 1

[0016] This embodiment provides a method for dyeing denim fabrics using an ionic liquid-based carrier, comprising the following steps: S1. The ionic liquid-based carrier, indigo particles, and sodium alginate thickener are mixed evenly in a mass ratio of 38:30:32 to obtain the dye agent. The particle size of the indigo particles is less than or equal to 0.5 μm. The ionic liquid-based carrier is composed of [BMIM]BF4, PEG400, BASF MA-80, nano silica, and deionized water in a mass ratio of 65:22:7:1:5. S2. Coat the dye onto the base film at a speed of 18 m / min and a temperature of 45°C to form a transfer film. S3. Apply the transfer film to the denim fabric and roll the transfer film for 60 seconds at a temperature of 50℃, a pressure of 0.15MPa, and a humidity of 90% for initial penetration; the denim fabric is 12oz stretch denim. S4. After initial penetration at 55℃, 0.28Mpa, and 95% humidity, the transfer film undergoes enhanced penetration for 30 seconds. S5. Use 100℃ saturated steam to steam the transfer area of ​​the denim fabric for 90 seconds to fix the color. After fixing, scrape off the residual material on the transfer film and use supercritical CO2 extraction at 32.5MPa and 45℃ for 40 minutes.

[0017] The pore size was tested using the BET nitrogen adsorption method. The denim was degassed at 105℃ for 6 hours, and an adsorption / desorption isotherm of N2 was established at liquid nitrogen temperature. The pore size distribution was calculated using the BJH model. The average pore size of the denim before initial infiltration was measured to be 2.1 nm, and the average pore size of the denim after initial infiltration was 4.2 nm.

[0018] Comparative Example 1 The comparative staining method is similar to that in Example 1, except that the ionic liquid-based carrier has a concentration of 20 g / L for o-dichlorobenzene and a concentration of 5 g / L for sodium tetraborate.

[0019] Comparative Example 2 The ionic liquid-based support in this comparative example is the same as that in Comparative Example 1, except that the staining method used is a hot-melt staining method, and the steps are as follows: S1. Denim fabric is impregnated in dye at 80°C with a liquid retention rate of 70%. S2, Pre-dry with 100℃ hot air for 2 minutes; S3, set at 180℃ for 1 minute; S4, wash with soap at 80℃ and then rinse with cold water.

[0020] The pore size was tested using the BET nitrogen adsorption method. The denim was degassed at 105℃ for 6 hours, and an adsorption / desorption isotherm of N2 was established at liquid nitrogen temperature. The pore size distribution was calculated using the BJH model. The average pore size of the denim before initial infiltration was measured to be 2.1 nm, and the average pore size of the denim after initial infiltration was 1.2 nm.

[0021] Comparative Example 3 The comparative staining method is similar to that in Example 1, except that the ionic liquid-based carrier is [BMIM]BF4.

[0022] Comparative Example 4 The comparative staining method is similar to that in Example 1, except that the ionic liquid-based carrier is a mixture of [BMIM]BF4, PEG200, BASF MA-80, nano silica and deionized water in a mass ratio of 65:22:7:1:5.

[0023] Comparative Example 5 The comparative staining method is similar to that in Example 1, except that the ionic liquid-based carrier is a mixture of [BMIM]BF4, PEG600, BASF MA-80, nano silica and deionized water in a mass ratio of 65:22:7:1:5.

[0024] Comparative Example 6 The comparative staining method is similar to that in Example 1, except that the ionic liquid-based carrier is a mixture of [BMIM]BF4, PEG400, JFC penetrant, nano silica and deionized water in a mass ratio of 65:22:7:1:5.

[0025] Comparative Example 7 The comparative staining method is similar to that in Example 1, except that the ionic liquid-based carrier is a mixture of [BMIM]BF4, PEG400, Triton X-100, nano silica and deionized water in a mass ratio of 65:22:7:1:5.

[0026] Comparative Example 8 The comparative staining method is similar to that in Example 1, except that the ionic liquid-based carrier is a mixture of [BMIM]BF4, PEG400, nano silica and deionized water in a mass ratio of 65:22:1:5.

[0027] Comparative Example 9 The comparative staining method is similar to that in Example 1, except that the ionic liquid-based carrier is a mixture of [BMIM]BF4, PEG400, BASF MA-80 and deionized water in a mass ratio of 65:22:7:5.

[0028] Comparative Example 10 The comparative staining method is similar to that in Example 1, except that the ionic liquid-based carrier is a mixture of [BMIM]BF4, PEG400 and deionized water in a mass ratio of 65:22:5.

[0029] The denim fabrics of Example 1 and Comparative Examples 1-10 were subjected to penetration depth testing using SEM cross-sectional analysis. The dyed areas of the denim fabric were first treated with 5 nm thick gold sputtering, and observed under a field emission electron microscope with an accelerating voltage of 5 kV. The denim fabric was rapidly cooled with liquid nitrogen at -196℃ to prevent deformation, then embedded in OCT and sectioned at low temperature. The unstained areas were then stained with 0.1% Coomassie Brilliant Blue for 30 min to mark them. The staining depth was then measured by Z-axis scanning stepping using a confocal microscope. The results are shown in Table 1.

[0030]

[0031] Therefore, it can be seen that the ionic liquid-based carrier of Example 1 has a good promoting effect on the dyeing depth of indigo pigment in denim fabric.

[0032] To verify the anti-crystallization effect of nano-silica, Example 1 and Comparative Examples 8-10 were observed, and the results are shown in Table 2.

[0033]

[0034] The above embodiments are only some preferred embodiments of the present invention and should not be construed as limiting the scope of protection of the present invention. Any non-substantial changes and substitutions made by those skilled in the art based on the present invention shall fall within the scope of protection claimed by the present invention.

Claims

1. An ionic liquid-based support, characterized in that , comprising the following components in mass fraction: [BMIM]BF4 60-70 parts; PEG400 20-25 parts; Sulfonic acid-based acrylic ester penetrant 5-8 parts; Nano-silica 1-3 parts; Deionized water 5-10 parts.

2. The ionic liquid-based support of claim 1, wherein, The sulfonic acid-based acrylic ester penetrant is BASF MA-80.

3. The ionic liquid-based support of claim 2, wherein, The mass ratio of the [BMIM]BF4, PEG400, BASF MA-80, nano-silica and deionized water is 65:22:7:1:

5.

4. A method of dyeing denim fabric with the ionic liquid-based carrier according to claim 3, characterized in that, Comprising the following steps: S1, uniformly mixing the ionic liquid-based carrier, indigo particles and sodium alginate thickener in a mass ratio of 38:30:32 to obtain a dye agent, the particle size of the indigo particles being less than or equal to 0.5 μm; S2, coating the dye agent on a base film to form a transfer film; S3, covering the transfer film on a denim fabric, and rolling the transfer film for 60 s at a temperature of 50℃ and a pressure of 0.15 MPa for initial penetration; S4, intensively penetrating the transfer film after initial penetration at a temperature of 55℃ and a pressure of 0.28 MPa for 30 s; S5, fixing the color on the penetrated area, and recovering the residual material on the transfer film after fixing.

5. The process for dyeing denim fabrics according to claim 4, characterized in that, The humidity for initial penetration is 90%, and the humidity for intensive penetration is 95%.

6. The process for dyeing denim fabrics according to claim 5, characterized in that, The coating speed in step S2 is 18 m / min, and the coating temperature is 45℃.

7. The method of dyeing denim fabric according to claim 6, wherein the ionic liquid-based carrier is used in an amount of 0.1 to 10 parts by weight per 100 parts by weight of the denim fabric. Step S5 uses 100℃ saturated steam to steam the transfer area of the denim fabric for 90 s.

8. The process for dyeing denim fabrics according to claim 6, characterized in that, Step S5 scrapes the residual material on the transfer film, and uses supercritical CO2 extraction method to extract for 40 min at 32.5 MPa and 45℃.

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