TWI809793B - Decolorization method for polyester textile - Google Patents

Abstract

A decolorization method for polyester textile in which the polyester textile is a textile dyed with dispersed dye, and the decolorization method includes providing a first solution and a second solution first, wherein the first solution includes water and a swelling agent, the second solution includes water and a surfactant. Then, the polyester textile is first impregnated into the first solution, and a first heat treatment is performed to swell the polyester textile and to release the dispersed dye. After the first heat treatment, the heat treated polyester textile is taken out, and then impregnated into the second solution for a second heat treatment, so that the surfactant can extract and disperse the dispersed dye.

Description

Decolorization method of polyester textiles

The invention relates to a decolorization technology of textiles, in particular to a decolorization method of polyester textiles.

The circular economy production strategy jointly formulated by world-renowned textile brands is to increase the use of recycled polyester by 25% in 2025, and achieve 100% use of recycled polyester/sustainable material textiles in 2030.

However, the current source of fiber recycled materials is limited to surface decolorization, and residual dyes are likely to cause technical bottlenecks such as cracking of recycled fibers during the remanufacturing process and failure to spin, which limits the reusability of polyester textiles.

The invention provides a method for decolorizing polyester textiles, which can effectively extract disperse dyes in fibers, achieve the purpose of decolorizing polyester fibers, and further improve the reusability of polyester textiles.

The method for decoloring polyester textiles of the present invention is to decolorize polyester textiles dyed with disperse dyes. The decolorization method includes first providing a first solution and a second solution, wherein the first solution includes water and a swelling agent, and the second solution includes water and a surfactant. Then, first impregnate the polyester textile into the first solution, and perform a first heat treatment, so that the polyester textile swells and releases the disperse dye. After the first heat treatment, the treated polyester textile is taken out, and then impregnated into the second solution for a second heat treatment, so that the surfactant can extract and disperse the disperse dye.

Based on the above, the present invention uses the swelling agent to perform the first heat treatment to swell the molecular chains of the polyester fiber first, and then uses the second heat treatment with a surfactant to extract the disperse dyes to achieve the effect of deep decolorization between the molecular chains .

In order to make the above-mentioned features and advantages of the present invention more comprehensible, the following specific embodiments are described in detail as follows.

Fig. 1 is a diagram of the decolorization steps of a polyester textile according to an embodiment of the present invention. In Figure 1, the decolorization method of this embodiment is aimed at polyester textiles dyed with disperse dyes, and polyester textiles can be fiber products made of pure polyester fibers (polyethylene terephthalate, PET) Or a polyester fiber blended with a little elastic fiber (Spandex), such as blending less than 25% or less than 12% elastic fiber.

First, in step S100, a first solution is provided, wherein the first solution basically includes water and a swelling agent. The swelling agent can be listed but not limited to C3-C8 alcohols, C4-C8 ketones, phenols or the combination of the above, wherein C3-C8 alcohols such as 1-butanol, 1-hexanol, etc.; C4 ~C8 ketones such as acetophenone, acetone, butanone, etc.; phenols such as phenol, m-cresol (m-Cresol), o-phenylphenol, p-phenylphenol, etc. The concentration of the swelling agent in the first solution may be 1 wt% to 30 wt%, preferably 1 wt% to 25 wt%, more preferably 1 wt% to 20 wt%.

In step S110, a second solution is provided, wherein the second solution includes water and a surfactant. In one embodiment, the surfactant can be isopropanol; in another embodiment, the surfactant can be a water-soluble anionic surfactant, such as selected from polynaphthaldehyde sulfonic acid sodium salt Its derivatives, sodium diisooctyl sulfosuccinate and its derivatives, or a combination of the foregoing. If the surfactant in the second solution is isopropanol, its concentration may be 5 wt% to 20 wt%, preferably 5 wt% to 10 wt%. If the surfactant in the second solution is a water-soluble anionic surfactant, its concentration may be 0.1 wt% to 1.0 wt%, preferably 0.1 wt% to 0.5 wt%.

Next, impregnate the polyester textile into the first solution, and perform the first heat treatment in step S120, so that the polyester textile swells and releases the disperse dye, wherein the temperature of the first heat treatment is as high as Based on the glass transition temperature Tg of polyester fiber, for example, 80°C to 140°C. From the point of view of saving energy, it can be 80°C to 100°C. The time for the first heat treatment is within 4 hours, such as within 2 hours or within 0.5 hours.

After the first heat treatment in step S120, take out the treated polyester textile, and then impregnate it into the second solution for the second heat treatment in step S130, so that the surfactant in the second solution can extract and disperse the dispersed type Dyes, wherein the temperature of the second heat treatment is higher than the glass transition temperature Tg of the polyester fiber, for example, 80°C-140°C. From the point of view of saving energy, it can be 80°C to 100°C. The time for the second heat treatment can be set within 60 minutes, such as within 30 minutes or within 20 minutes.

The following experiments are listed to verify the efficacy of the present invention, but the present invention is not limited to the following content.

<Material>

Fiber to be decolorized: polyester fabric sample dyed with Blue 79 dye (fabric weight: 1g), the color space L*a*b* measured by a spectrophotometer is 25.20/-1.03/-23.97.

Swelling agents: acetophenone (CAS 98-86-2), phenol (CAS 108-95-2), acetone (CAS 67-64-1), butanone (CAS 78-93-3).

Surfactant: Isopropanol (CAS 67-63-0), Polynaphthalene Sulfonate Sodium Salt (CAS 9084-06-4), Diisooctyl Sulfosuccinate Sodium Salt (CAS 577-11-7 ).

<Experimental examples 1 to 11>

According to the contents of Table 1 and Table 2 below, the swelling agent was dissolved in deionized water to form the first solution. According to the contents of Table 1 and Table 2, the surfactant was dissolved in deionized water to form the second solution.

First heat the first solution to the temperature of the first heat treatment, and then put the blue polyester cloth sample into the first solution to perform the first heat treatment. After the treatment is completed, the polyester cloth sample is taken out and placed in the second solution heated to the temperature of the second heat treatment for the second heat treatment. After completion the polyester swatches were rinsed in deionized water and dried.

<Comparative example>

According to Table 1 below, except that deionized water was used for the first heat treatment, other steps were the same as in Experimental Example 4.

Table 1 Experimental example comparative example 1 2 3 4 5 6 7 Swelling agent (wt %) phenol 5 acetone 5 butanone 5 Acetophenone 5 5 5 5 Surfactant (wt %) Isopropanol 10 10 10 Sodium Polynaphthalene Sulfonate 0.1 0.1 Sodium diisooctyl sulfosuccinate 0.1 0.1 0.5 first heat treatment temperature (°C) 90 90 90 90 90 90 90 90 time (hours) 2 2 2 2 2 2 2 2 second heat treatment temperature (°C) 90 90 90 90 90 90 90 90 time (minutes) 20 20 20 20 20 5 20 20

Table 2 Experimental example 8 9 10 11 Swelling agent (wt %) phenol acetone butanone Acetophenone 2.5 1 5 10 Surfactant (wt %) Isopropanol Sodium Polynaphthalene Sulfonate Sodium diisooctyl sulfosuccinate 0.1 0.1 0.1 0.1 first heat treatment temperature (°C) 90 90 90 90 time (hours) 2 2 0.5 2 second heat treatment temperature (°C) 90 90 90 90 time (minutes) 20 20 20 20

<analyze>

The color space L*a*b* values of the treated polyester swatches were measured using a spectrophotometer.

First, the color spaces of Experimental Examples 1-7 and Comparative Example together with the blue polyester swatches before decolorization and the white polyester swatches before dyeing are listed in Table 3 below.

table 3 L*a*b* Before bleaching (blue cloth) 25.20/-1.03/-23.97 Before dyeing (white cloth) 91.70/-0.84/2.97 Experimental example 1 26.27/-6.27/-27.05 Experimental example 2 25.95/-5.27/-26.07 Experimental example 3 29.56/-7.34/-27.49 Experimental example 4 43.17/-4.79/-18.78 Experimental example 5 63.33/-4.80/-13.77 Experimental example 6 60.15/-4.71/-12.18 Experimental example 7 63.54/-3.78/-10.03 comparative example 19.63/1.71/-21.57

It can be obtained from Table 3 that the L value of the comparative example without swelling agent is only 19.63, so there is no decolorization effect at all. In comparison, the experimental examples 1 to 7 of the present invention all have larger L values than the comparative examples, so the present invention has a certain degree of decolorization effect, and those with less obvious decolorization effects are suitable for making dark-colored fabrics after recycling.

Moreover, according to the data in Table 3, it can be seen that at the same swelling agent concentration, the experimental examples 4-7 using acetophenone as the swelling agent and changing to a low concentration of water-soluble anionic surfactant have a higher L value than the decolorizing agent. The L value (25.20) of the former blue cloth is much larger.

Then, the color spaces of Experimental Examples 7-11 are listed in Table 4 below.

Table 4 L*a*b* Experimental example 7 63.54/-3.78/-10.03 Experimental example 8 42.52/-8.17/-23.10 Experimental example 9 39.28/-9.15/-24.03 Experiment 10 50.42/-5.77/-9.91 Experiment 11 63.89/-3.32/-11.97

According to the data in Table 4, it can be seen that if the parameters of the two heat treatments are the same in the method of the present invention, the following conditions can achieve excellent decolorization effects (Experimental Example 7, Experimental Example 11). 1) The swelling agent uses 5 wt% to 10 wt% acetophenone. 2) Surfactant Use 0.1 wt% to 0.5 wt% water-soluble anionic surfactant.

In summary, the decolorization method of the present invention is to carry out the first heat treatment through the aqueous solution containing the swelling agent to swell the polyester fiber molecular chain, and then carry out the second heat treatment with a surfactant to disperse the polyester fiber. The permanent dye is extracted to achieve the effect of deep decolorization between molecular chains. Therefore, the recyclability of polyester textiles can be improved by the method of the present invention.

Although the present invention has been disclosed above with the embodiments, it is not intended to limit the present invention. Anyone with ordinary knowledge in the technical field may make some changes and modifications without departing from the spirit and scope of the present invention. The scope of protection of the present invention should be defined by the scope of the appended patent application.

S100, S110, S120, S130: steps

Fig. 1 is a diagram of the decolorization steps of a polyester textile according to an embodiment of the present invention.

S100, S110, S120, S130: steps

Claims (7)

A method for decoloring polyester textiles, wherein the polyester textiles are textiles dyed with disperse dyes, the decolorization method includes: providing a first solution, wherein the first solution includes water and a swelling agent, wherein the The swelling agent includes C3~C8 alcohols, C4~C8 ketones, phenols, or a combination of the foregoing; providing a second solution, wherein the second solution includes water and a water-soluble anionic surfactant, wherein the water-soluble The positive anionic surfactant is selected from polynaphthaldehyde sulfonic acid sodium salt and its derivatives, sulfosuccinic acid diisooctyl sodium salt and its derivatives, or a combination of the foregoing; impregnating the polyester textile into the first a solution, and perform a first heat treatment to swell the polyester textile and release the disperse dye; and after performing the first heat treatment, take out the treated polyester textile, and then impregnated into the second solution for second heat treatment, so that the water-soluble anionic surfactant extracts and disperses the disperse dye. The method for decolorizing polyester textiles according to claim 1, wherein the concentration of the swelling agent in the first solution is 1wt%~30wt%. The method for decolorizing polyester textiles according to claim 1, wherein the temperature of the first heat treatment is 80°C to 140°C. The method for decolorizing polyester textiles as claimed in claim 1, wherein the time of the first heat treatment is within 4 hours. The method for decolorizing polyester textiles according to claim 1, wherein the concentration of the water-soluble anionic surfactant in the second solution is 0.1wt%~1.0wt%. The method for decolorizing polyester textiles according to claim 1, wherein the temperature of the second heat treatment is 80°C to 140°C. The method for decolorizing polyester textiles as claimed in item 1, wherein the time of the second heat treatment is within 60 minutes.

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