Degumming and decolorizing method for polyester fabric

Abstract

The invention provides a degumming and decoloring method for polyester fabric. A first polyester fabric to which a dye and a film or a surface treating agent are attached is provided. And stripping the adhesive film or the surface treating agent on the first polyester fabric through a combined formula of an alkaline aqueous solution and a catalyst so as to obtain a second polyester fabric. And then decolorizing the second polyester fabric through a combination of a chemical reduction method and a chemical oxidation method to obtain a third polyester fabric. Therefore, the adhesive film, the surface treating agent and the dye on the polyester fabric can be effectively removed.

Description

Technical Field

[0001] The invention relates to a decolorization method, in particular to a degumming and decolorization method for polyester fabric. Background Art

[0002] Generally, dyed polyester fabrics have dyes and at least one of a surface treatment agent and an adhesive film. The adhesive film may be, for example, polyurethane (PU) glue, polymethyl methacrylate (PMMA, acrylic) glue, polyurethane (PU) film, thermoplastic polyurethane (TPU) film, or polyether ester elastomer (TPEE) film. The surface treatment agent may be, for example, a water repellent. For recycled polyester fabrics, the dyes, surface treatment agents, and adhesive films attached to the recycled polyester fabrics need to be removed.

[0003] Currently known methods for decolorizing polyester fabrics include solvent extraction and chemical bleaching. For example, the solvent extraction method can refer to Taiwan Invention Patent Publication No. 1481762, which uses solvent vapor to extract the dyes colored on polyester fibers. For example, the chemical bleaching method can refer to U.S. Patent No. 5261925A1, which decolorizes polyester fabrics through ozone oxidation reaction, and U.S. Patent No. 7981337B2 decolorizes polyester fabrics through reduction reaction. However, the above decolorization methods can usually only remove the dyes, but cannot remove the surface treatment agent or film. Furthermore, when the surface treatment agent and / or film on the colored polyester fabric is not removed, it may cause difficulty in subsequent dye removal.

[0004] Therefore, developing a method for effectively removing dyes, surface treatment agents and adhesive films attached to polyester fabrics is an important goal in the art. Summary of the invention

[0005] The invention is directed to a method for removing adhesive and coloring polyester fabrics, which can effectively remove the surface treatment agent, adhesive film and dye attached to the polyester fabrics.

[0006] The degumming and decoloring method of polyester fabric of the present invention comprises providing a first polyester fabric with a dye and a glue film or a surface treatment agent attached thereto, and sequentially performing a degumming operation and a decoloring operation. The degumming operation comprises the following steps: mixing a catalyst in a first alkaline aqueous solution to prepare a catalyst solution; immersing the first polyester fabric in the catalyst solution to remove the glue film or the surface treatment agent, and obtaining a second polyester fabric with a dye attached thereto. The decoloring operation comprises the following steps: providing a reduction decoloring solution and an oxidation decoloring solution; immersing the second polyester fabric in the reduction decoloring solution to perform a reduction decoloring reaction; immersing the second polyester fabric in the oxidation decoloring solution to perform an oxidation decoloring reaction, and obtaining a third polyester fabric.

[0007] In one embodiment of the present invention, the adhesive film is selected from at least one of PU adhesive film, TPU adhesive film, TPEE adhesive film and acrylic adhesive, and the surface treatment agent is selected from at least one of fluorine-containing water repellent agent and fluorine-free water repellent agent.

[0008] In one embodiment of the present invention, the alkaline aqueous solution includes at least one selected from the group consisting of an alkali metal hydroxide solution, an alkaline earth metal hydroxide solution, an alkaline earth metal carbonate solution, and an alkaline earth metal bicarbonate solution.

[0009] In one embodiment of the present invention, the catalyst comprises at least one selected from quaternary ammonium salts, quaternary ammonium bases, quaternary phosphonium salts and crown ethers.

[0010] In one embodiment of the present invention, the quaternary ammonium salt includes at least one selected from benzyltributylammonium chloride, benzyltriethylammonium chloride, tetrabutylammonium bromide, tetrabutylammonium chloride, tetrabutylammonium hydrogen sulfate, trioctylmethylammonium chloride, dodecyltrimethylammonium chloride, tetradecyl and trimethylammonium chloride.

[0011] In one embodiment of the present invention, the quaternary ammonium base includes at least one selected from phenyltrimethylammonium hydroxide, benzyltriethylammonium hydroxide, benzyltrimethylammonium hydroxide, methyltriethylammonium hydroxide, tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide and tetrabutylammonium hydroxide.

[0012] In one embodiment of the present invention, the quaternary phosphonium salt includes at least one selected from butyltriphenylphosphonium bromide, ethyltriphenylphosphonium acetate, ethyltriphenylphosphonium iodide, ethyltriphenylphosphonium bromide and benzyltriphenylphosphonium chloride.

[0013] In one embodiment of the present invention, the crown ether includes at least one selected from 12-crown-4, 15-crown-5, 18-crown-6, dibenzo-18-crown-6 and diaza-18-crown-6.

[0014] In one embodiment of the present invention, the concentration of the aqueous catalyst solution is 0.5 to 20 g / L, and the weight ratio of the aqueous catalyst solution to the first polyester fabric is 5:1 to 50:1.

[0015] In one embodiment of the present invention, the reaction conditions for removing the adhesive film or the surface treatment agent are: a reaction temperature of 60 to 140° C. and a reaction time of 5 to 60 minutes.

[0016] In one embodiment of the present invention, the above-mentioned reducing decolorizing solution comprises a reducing agent and water, and the reducing agent is at least one selected from ammonium dodecyl polyoxyethylene ether sulfate, sodium dithionite, sodium thiosulfate, sodium formaldehyde sulfoxylate and thiourea dioxide.

[0017] In one embodiment of the present invention, the concentration of the reducing decolorizing solution is 0.5 to 15 g / L, and the weight ratio of the reducing decolorizing solution to the second polyester fabric is 5:1 to 50:1.

[0018] In one embodiment of the present invention, the conditions of the reduction decolorization reaction are: reaction temperature is 90 to 140° C., and reaction time is 5 to 60 minutes.

[0019] In one embodiment of the present invention, the oxidative decolorizing solution comprises an oxidant and water, and the oxidant is at least one selected from hydrogen peroxide, sodium nitrate, sodium nitrite, chlorite, hypochlorite, ammonium persulfate and sodium persulfate.

[0020] In one embodiment of the present invention, the concentration of the oxidative bleaching liquid is 0.5 to 15 g / L, and the weight ratio of the oxidative bleaching liquid to the second polyester fabric is 5:1 to 50:1.

[0021] In one embodiment of the present invention, the conditions of the above-mentioned oxidative decolorization reaction are: reaction temperature is 60 to 130° C., and reaction time is 5 to 60 minutes.

[0022] In one embodiment of the present invention, the order of the above-mentioned decolorization operation is: firstly, the second polyester fabric is subjected to a reduction decolorization reaction, and then, the second polyester fabric subjected to the reduction decolorization reaction is subjected to an oxidation decolorization reaction.

[0023] In one embodiment of the present invention, the order of the above-mentioned decolorization operation is: firstly, the second polyester fabric is subjected to an oxidative decolorization reaction, and then, the second polyester fabric subjected to the oxidative decolorization reaction is subjected to a reductive decolorization reaction.

[0024] In one embodiment of the present invention, the above-mentioned degumming and decoloring method further comprises drying the third polyester fabric. The drying conditions are: drying temperature is 120° C., and drying time is 2 to 4 hours.

[0025] Based on the above, the degumming and decoloring method of polyester fabric of the present invention utilizes a combination of an alkaline aqueous solution and a catalyst to first remove various types of surface treatment agents or adhesive films on the surface of the polyester fabric, and then decolorizes the polyester fabric by a combination of a chemical reduction method and a chemical oxidation method, thereby effectively removing the surface treatment agent or adhesive film and dye on the material of the polyester fabric. In addition, compared with the solvent extraction method using an organic solvent, the present invention uses an aqueous solution (i.e., a catalyst aqueous solution, a reduction decolorizing solution, and an oxidation decolorizing solution) to remove the glue and decolorize the polyester fabric, which is obviously more environmentally friendly. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 The present invention is a flow chart of the method for removing glue and decolorizing polyester fabric.

[0027] Description of Reference Numerals

[0028] S100, S110, S120, S130: steps. DETAILED DESCRIPTION

[0029] Hereinafter, embodiments of the present invention will be described in detail. However, these embodiments are illustrative only, and the present invention is not limited thereto.

[0030] In this article, the range expressed by "a value to another value" is a summary expression method to avoid listing all the values ​​in the range one by one in the specification. Therefore, the description of a specific numerical range covers any value in the numerical range and a smaller numerical range defined by any value in the numerical range, just as the arbitrary value and the smaller numerical range are written in the description text of the specification.

[0031] It should be understood that although the terms "first", "second", "third" and the like may be used herein to describe various components or signals, these components or signals should not be limited by these terms. These terms are mainly used to distinguish one component from another component, or one signal from another signal. In addition, the term "or" used herein may include any one or more combinations of the associated listed items depending on the actual situation.

[0032] Figure 1 This is a flow chart of the method for removing glue and decolorizing polyester fabric of the present invention. Figure 1 , perform step S100: provide a first polyester fabric with a dye and an adhesive film or a surface treatment agent attached thereto. Specifically, polyester fabric generally refers to articles woven from polyester fibers, such as clothing, cloth bags, bed sheets, etc. Polyester fibers are man-made fibers, and may include (but are not limited to) polyethylene terephthalate (PET) fibers, polybutylene terephthalate (PBT) fibers, polytrimethylene terephthalate (PTT) fibers, poly(1,4-cyclohexanedimethyl terephthalate) (PCT) fibers, and poly(ethylene 2,6-tetraphthalate) (PEN) fibers. The present invention does not particularly limit the types of polyester fibers.

[0033] In this embodiment, the dye may be, for example, disperse dyes, but not limited thereto. In some embodiments, the adhesive film may be, for example, a fluorine-containing water-repellent (such as perfluorooctanoic acid and salts, perfluorooctane sulfonyl compounds, alkylphenol polyoxyethylene ethers, perfluorohexane sulfonyl compounds or sulfonates), a fluorine-free water-repellent (such as silicone water-repellent and hydrocarbon long chain water-repellent, commercial products 3M PM-3705, PM-3888, Ruco-dry ECO Plus, etc.) or a combination thereof, but not limited thereto. The adhesive film may be, for example, a polyurethane adhesive film, a thermoplastic polyurethane film, a polyether ester elastomer adhesive film, a polymethyl methacrylate (acrylic) adhesive or a combination thereof, but not limited thereto.

[0034] Next, step S110 is performed: the first polyester fabric is subjected to a degumming operation. The degumming operation includes the following steps: first, a catalyst is mixed in an alkaline aqueous solution to prepare a catalyst solution; then, the first polyester fabric is immersed in the catalyst solution to remove the adhesive film or the surface treatment agent, and a second polyester fabric with a dye attached thereto is obtained. In this article, the second polyester fabric refers to the polyester fabric after the degumming operation, that is, the second polyester fabric has a dye attached thereto, but no adhesive film and surface treatment agent are attached thereto, or only a trace amount of adhesive film and / or a trace amount of surface treatment agent are attached thereto. Specifically, in this stage, the surface treatment agent and the adhesive film on the polyester fabric material are removed through a mixed formula of a catalyst and an alkaline aqueous solution.

[0035] In the present invention, the catalyst may be, for example, at least one of a quaternary ammonium salt, a quaternary ammonium base, a quaternary phosphonium salt, and a crown ether. In some embodiments, the quaternary ammonium salt may include (but is not limited to) at least one selected from benzyltributylammonium chloride, benzyltriethylammonium chloride, tetrabutylammonium bromide, tetrabutylammonium chloride, tetrabutylammonium hydrogen sulfate, trioctylmethylammonium chloride, dodecyltrimethylammonium chloride, tetradecyl, and trimethylammonium chloride. In some embodiments, the quaternary ammonium base may include (but is not limited to) at least one selected from phenyltrimethylammonium hydroxide, benzyltriethylammonium hydroxide, benzyltrimethylammonium hydroxide, methyltriethylammonium hydroxide, tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, and tetrabutylammonium hydroxide. In some embodiments, the quaternary phosphonium salt may include (but is not limited to) at least one selected from butyltriphenylphosphonium bromide, ethyltriphenylphosphonium acetate, ethyltriphenylphosphonium iodide, ethyltriphenylphosphonium bromide, and benzyltriphenylphosphonium chloride. In some embodiments, the crown ether may include, but is not limited to, at least one selected from 12-crown-4, 15-crown-5, 18-crown-6, dibenzo-18-crown-6, and diaza-18-crown-6.

[0036] In the present invention, the alkaline aqueous solution may be, for example, an alkali metal hydroxide solution, an alkaline earth metal hydroxide solution, an alkaline earth metal carbonate solution, an alkaline earth metal bicarbonate solution, or a combination thereof. In some embodiments, the alkali metal hydroxide may include (but is not limited to) at least one selected from sodium hydroxide (NaOH) and potassium hydroxide (KOH). In some embodiments, the alkaline earth metal hydroxide may include (but is not limited to) at least one selected from calcium hydroxide (Ca(OH)2), barium hydroxide (Ba(OH)2) and magnesium hydroxide (Mg(OH)2). In some embodiments, the alkaline earth metal carbonate may include (but is not limited to) at least one selected from magnesium carbonate and calcium carbonate. In some embodiments, the alkaline earth metal bicarbonate may include (but is not limited to) at least one selected from magnesium bicarbonate and calcium bicarbonate. Here, since the alkaline aqueous solution is used as the solvent, environmental pollution caused by organic solvents can be avoided.

[0037] In some embodiments, the concentration of the catalyst in the catalyst solution may be, for example, 0.5 to 20 g / L (g / L), preferably, 2 to 10 g / L. In some embodiments, the bath ratio (weight ratio) of the catalyst solution to the first polyester fabric may be, for example, 5:1 to 50:1, preferably, 8:1 to 20:1. In some embodiments, the reaction conditions for removing the adhesive film are: the reaction temperature may be, for example, 60 to 140°C, and the reaction time may be, for example, 5 to 60 minutes (min); preferably, the reaction temperature may be, for example, 100 to 130°C, and the reaction time may be, for example, 20 to 40 minutes. After the degumming operation is completed, the second polyester fabric may be filtered and cleaned.

[0038] Next, step S120 is performed: a decolorization operation is performed. The decolorization operation includes at least the following steps: providing a reduction decolorization liquid and an oxidation decolorization liquid; immersing the second polyester fabric in the reduction decolorization liquid to perform a reduction decolorization reaction; immersing the second polyester fabric after the reduction decolorization reaction in an oxidation decolorization liquid to perform an oxidation decolorization reaction; and removing the dye to obtain a third polyester fabric. In this article, the third polyester fabric refers to the polyester fabric after the degumming operation and the dyeing operation, that is, there is no dye and glue film attached to the third polyester fabric, or only a trace amount of glue film and / or a trace amount of dye is attached. Specifically, in this stage, the dye on the polyester fabric material is removed through a reduction decolorization reaction and an oxidation decolorization reaction.

[0039] In the present invention, the reducing decolorizing liquid is a reducing agent aqueous solution. In some embodiments, the reducing agent may include (but is not limited to) at least one selected from ammonium lauryl polyoxyethylene ether sulfate, sodium dithionite (hydrosulfite), sodium thiosulfate, sodium formaldehyde sulfoxylate and thiourea dioxide. Here, since the aqueous solution is used as a solvent, environmental pollution caused by organic solvents can be avoided.

[0040] Specifically, the second polyester fabric after degumming is immersed in a reduction decolorizing solution, wherein the reducing agent can reduce the dye molecules, for example, the N=N double bond of the azo dye can be reduced to the NH2 single bond, thereby removing part of the dye (i.e., the dye that can be removed through the reduction reaction). In some embodiments, the concentration of the reducing agent in the reduction decolorizing solution can be, for example, 0.5 to 15 g / L, preferably, 2 to 10 g / L. In some embodiments, the bath ratio (weight ratio) of the reduction decolorizing solution to the second polyester fabric can be, for example, 5:1 to 50:1, preferably, 8:1 to 20:1. In some embodiments, the conditions of the reduction decolorizing reaction are: the reaction temperature can be, for example, 90 to 140°C, and the reaction time can be, for example, 5 to 60 minutes. Preferably, the reaction temperature can be, for example, 120 to 140°C, and the reaction time can be, for example, 20 to 40 minutes. When within the above temperature range and time range, the reducing agent can have good reaction activity and can effectively remove the dye on the polyester fabric.

[0041] In the present invention, the oxidative decolorizing solution is a combination of an oxidant and water. In some embodiments, the oxidant may include (but is not limited to) at least one selected from hydrogen peroxide, sodium nitrate, sodium nitrite, sodium chlorite, calcium chlorite, sodium hypochlorite, calcium hypochlorite, ammonium persulfate, and sodium persulfate. Here, since an aqueous solution is used as a solvent, environmental pollution caused by an organic solvent can be avoided.

[0042] Specifically, the second polyester fabric after the reduction decolorization reaction is immersed in an oxidative decolorization solution, wherein the oxidant oxidizes the dye and destroys the conjugated structure, thereby removing part of the dye (i.e., the dye that can be removed through the oxidation reaction). In some embodiments, the concentration of the oxidant in the oxidative decolorization solution can be, for example, 0.5 to 15 g / L, preferably, 1 to 5 g / L. In some embodiments, the bath ratio (weight ratio) of the oxidative decolorization solution to the second polyester fabric can be, for example, 5:1 to 50:1, preferably, 8:1 to 20:1. In some embodiments, the conditions of the oxidative decolorization reaction are: the reaction temperature can be, for example, 60 to 120° C., and the reaction time can be, for example, 5 to 60 minutes. Preferably, the reaction temperature can be, for example, 70 to 100° C., and the reaction time can be, for example, 20 to 40 minutes. When within the above temperature range and time range, the oxidant can have good reactivity and can remove the dye on the polyester fabric.

[0043] In the decolorization operation, the second polyester fabric may be subjected to a reduction decolorization reaction first, and then to an oxidation decolorization reaction. In other embodiments, the second polyester fabric may be subjected to an oxidation decolorization reaction first, and then to a reduction decolorization reaction. The present invention does not limit the order of the decolorization reactions. It is worth noting that, in some cases, the decolorization effect of first performing a reduction decolorization reaction is better than the decolorization effect of first performing an oxidation decolorization reaction.

[0044] Next, step S130 is performed: drying the third polyester fabric. In some embodiments, the drying conditions are: the drying temperature may be, for example, 120° C., and the drying time may be, for example, 2 to 4 hours, but the present invention is not limited thereto. At this point, the degumming and decoloring of the polyester fabric of the present invention has been substantially completed.

[0045] The following examples are used to illustrate the practical effects of the method for removing glue and coloring the poly-finger fabric of the present invention. However, the following examples are not intended to limit the present invention.

[0046] Example

[0047] <Examples 1 to 12>

[0048] Examples 1 to 12 are steps of removing adhesive and decolorizing polyester fabrics with adhesive films of different types of materials or surface treatment agents (as shown in Table 1) and dyes attached to their surfaces. Each step is briefly described as follows:

[0049] (1) Glue removal

[0050] The catalyst (as shown in Table 1) is mixed with a sodium hydroxide aqueous solution to prepare a catalyst aqueous solution with a concentration of 0.5 to 20 g / L. Then, 10 g of polyester fabric is added to perform a degumming reaction, wherein the bath ratio of the catalyst solution to the polyester fabric is 5:1 to 50:1, the reaction temperature is 60 to 140°C, and the reaction time is 5 to 60 minutes. Then, the polyester fabric after the degumming operation is filtered and drained.

[0051] (2) Decolorization

[0052] The hydrosulfite is mixed with water to prepare a reduction decolorizing solution with a concentration of 0.5 to 15 g / L. Then, the polyester fabric that has undergone the degumming operation is added to perform a reduction decolorizing reaction, wherein the reaction temperature is 90 to 140° C. and the reaction time is 5 to 60 minutes. Then, the polyester fabric that has undergone the degumming operation and the reduction decolorizing reaction is filtered and drained.

[0053] Next, an aqueous solution of ammonium persulfate with a concentration of 0.5 to 15 g / L is added to carry out an oxidative decolorization reaction, wherein the reaction temperature is 60 to 120° C. and the reaction time is 5 to 60 minutes. Then, the polyester fabric after the degumming and decolorization operation is filtered and drained.

[0054] (3) Drying operation

[0055] The polyester fabric after degumming and decolorization is dried at a temperature of 120° C. for 2 to 4 hours.

[0056] <Comparative Example>

[0057] The comparative example is a step of decolorizing a polyester fabric with a film or a surface treatment agent and a dye attached to the surface:

[0058] (1) Decolorization

[0059] The hydrosulfite is mixed with water to prepare a reduction decolorizing solution with a concentration of 0.5 to 15 g / L. Then, 10 g of polyester fabric is added to perform a reduction decolorizing reaction, wherein the reaction temperature is 90 to 140° C. and the reaction time is 5 to 60 minutes. Then, the polyester fabric after the reduction decolorizing reaction is filtered and drained.

[0060] Next, an aqueous solution of ammonium persulfate with a concentration of 0.5 to 15 g / L is added to carry out an oxidative decolorization reaction, wherein the reaction temperature is 60 to 120° C. and the reaction time is 5 to 60 minutes. Then, the decolorized polyester fabric is filtered and drained.

[0061] (3) Drying operation

[0062] The decolorized polyester fabric is dried at a temperature of 120° C. for 2 to 4 hours.

[0063] <Decolorization effect evaluation>

[0064] Optical tests were performed on the polyester fabrics before treatment and after decolorization of Examples 1 to 12 and Comparative Example.

[0065] The L*a*b color system (using JIS Z8729 method) was measured using a colorimeter, where a higher L value indicates a whiter hue, a higher a value indicates a reddish hue, and a higher b value indicates a yellowish hue. The measurement results are shown in Table 1.

[0066] Table 1

[0067] sample <![CDATA[Film type * > Alkaline aqueous solution catalyst reducing agent Oxidants L a b Example 1 A Sodium hydroxide Tetrabutylammonium bromide Hydrocarbon Ammonium Persulfate 90.2 -0.2 5.2 Example 2 B Sodium hydroxide Tetrabutylammonium bromide Hydrocarbon Ammonium Persulfate 92.3 0.1 5.3 Example 3 C Sodium hydroxide Tetrabutylammonium bromide Hydrocarbon Ammonium Persulfate 91.5 0.3 6.2 Example 4 D Sodium hydroxide Tetrabutylammonium bromide Hydrocarbon Ammonium Persulfate 90.3 -0.3 4.5 Example 5 E Sodium hydroxide Tetrabutylammonium bromide Hydrocarbon Ammonium Persulfate 91.6 0.2 3.6 Example 6 F Sodium hydroxide Tetrabutylammonium bromide Hydrocarbon Ammonium Persulfate 92.2 0.4 4.8 Example 7 A Sodium hydroxide Tetrabutylammonium chloride Hydrocarbon Ammonium Persulfate 91.5 0.3 5.5 Example 8 A Sodium hydroxide Tetraethylammonium hydroxide Hydrocarbon Ammonium Persulfate 90.3 0.2 3.9 Example 9 A Sodium hydroxide Butyltriphenylphosphonium bromide Hydrocarbon Ammonium Persulfate 91.8 -0.5 4.3 Example 10 A Sodium hydroxide Benzyltriphenylphosphonium chloride Hydrocarbon Ammonium Persulfate 90.6 -0.3 4.7 Example 11 A Sodium hydroxide 18-Crown-6 Hydrocarbon Ammonium Persulfate 90.5 -0.8 5.3 Example 12 A Sodium hydroxide 12-Crown-4 Hydrocarbon Ammonium Persulfate 92.5 0.6 5.8 Comparative Example A Sodium hydroxide - Hydrocarbon Ammonium Persulfate 75.2 3.5 20.5

[0068] * A: PU glue; B: TPU glue; C: TPEE film; D: acrylic glue; E: fluorine-free water repellent (3M PM-3705); F: fluorine-containing water repellent (Daikin UNIDYNE TG-6071)

[0069] According to the results of the comparative example and Example 1, compared with the comparative example in which the polyester fabric is directly decolorized, Example 1 of the present invention in which the polyester fabric is first degummed before decolorization obtains a better decolorization effect in the decolorization operation. According to the results of Examples 1 to 6, the degumming treatment of the present invention can be applied to various types of adhesive films or surface treatment agents, such as PU adhesive, TPU adhesive, acrylic adhesive, TPEE film, fluorine-free water repellent and fluorine-containing water repellent. In addition, according to the results of Examples 1, 7 to 12, a variety of catalysts (such as tetrabutylammonium bromide, tetrabutylammonium chloride, tetraethylammonium hydroxide, butyltriphenylphosphonium bromide, benzyltriphenylphosphonium chloride, 18-crown-6 and 12-crown-4) can all be applied to the degumming operation of the present invention, and all help to improve the decolorization effect of the subsequent decolorization treatment.

[0070] In summary, the degumming and decoloring method of polyester fabric of the present invention utilizes a combination of an alkaline aqueous solution and a catalyst to first remove various types of adhesive films and treatment agents on the surface of the polyester fabric, and then decolorizes the polyester fabric by a combination of a chemical reduction method and a chemical oxidation method, thereby effectively removing the surface treatment agent or the back film material and dye on the polyester fabric. In addition, compared to the solvent extraction method using an organic solvent, the present invention uses an aqueous solution (i.e., a catalyst alkaline aqueous solution, a reduction decolorizing solution, and an oxidation decolorizing solution) to remove the glue and decolorize the polyester fabric, which is obviously more environmentally friendly.

[0071] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for removing glue and decolorizing polyester fabric, characterized in that: include: Providing a first polyester fabric with a dye and an adhesive film or a surface treatment agent attached thereto; Carry out glue removal operations, including: mixing a catalyst in an alkaline aqueous solution to prepare a catalyst solution; and Immersing the first polyester fabric in the catalyst solution to remove the adhesive film or the surface treatment agent and obtain a second polyester fabric with the dye attached thereto; and Carry out decolorization operations, including: Providing reduction decolorization solution and oxidation decolorization solution; immersing the second polyester fabric in the reduction decolorization liquid to perform a reduction decolorization reaction; immersing the second polyester fabric in the oxidative decolorization solution to perform an oxidative decolorization reaction; and The dye is removed and a third polyester fabric is obtained.

2. The method for removing glue and decolorizing according to claim 1, characterized in that: The adhesive film is selected from at least one of polyurethane adhesive film, thermoplastic polyurethane adhesive film, polyether ester elastomer adhesive film and acrylic adhesive, and the surface treatment agent is selected from at least one of fluorine-containing water repellent agent and fluorine-free water repellent agent.

3. The method for removing glue and decolorizing according to claim 1, characterized in that: The alkaline aqueous solution includes at least one selected from an alkali metal hydroxide solution, an alkaline earth metal hydroxide solution, an alkaline earth metal carbonate solution, and an alkaline earth metal bicarbonate solution.

4. The method for removing glue and coloring according to claim 1, characterized in that: The catalyst includes at least one selected from quaternary ammonium salts, quaternary ammonium bases, quaternary phosphonium salts and crown ethers.

5. The method for removing glue and decolorizing according to claim 4, characterized in that: The quaternary ammonium salt includes at least one selected from benzyltributylammonium chloride, benzyltriethylammonium chloride, tetrabutylammonium bromide, tetrabutylammonium chloride, tetrabutylammonium hydrogen sulfate, trioctylmethylammonium chloride, dodecyltrimethylammonium chloride, tetradecyl and trimethylammonium chloride.

6. The method for removing glue and decolorizing according to claim 4, characterized in that: The quaternary ammonium base includes at least one selected from phenyltrimethylammonium hydroxide, benzyltriethylammonium hydroxide, benzyltrimethylammonium hydroxide, methyltriethylammonium hydroxide, tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide and tetrabutylammonium hydroxide.

7. The method for removing glue and decolorizing according to claim 4, characterized in that: The quaternary phosphonium salt includes at least one selected from butyltriphenylphosphonium bromide, ethyltriphenylphosphonium acetate, ethyltriphenylphosphonium iodide, ethyltriphenylphosphonium bromide and benzyltriphenylphosphonium chloride.

8. The method for removing glue and coloring according to claim 4, characterized in that: The crown ether includes at least one selected from 12-crown-4, 15-crown-5, 18-crown-6, dibenzo-18-crown-6 and diaza-18-crown-6.

9. The method for removing glue and decolorizing according to claim 1, characterized in that: The concentration of the catalyst solution is 0.5 to 20 g / L, and the weight ratio of the catalyst solution to the first polyester fabric is 5:1 to 50:

1.

10. The method for removing glue and decolorizing according to claim 1, characterized in that: The reaction conditions for removing the adhesive film or the surface treatment agent are: a reaction temperature of 60 to 140° C. and a reaction time of 5 to 60 minutes.

11. The method for removing glue and decolorizing according to claim 1, characterized in that: The reducing decolorizing liquid comprises a reducing agent and water, and the reducing agent is at least one selected from ammonium dodecyl polyoxyethylene ether sulfate, sodium dithionite, sodium thiosulfate, sodium formaldehyde sulfoxylate and thiourea dioxide.

12. The method for removing glue and decolorizing according to claim 1, characterized in that: The concentration of the reducing decolorizing liquid is 0.5 to 15 g / L, and the weight ratio of the reducing decolorizing liquid to the second polyester fabric is 5:1 to 50:

1.

13. The method for removing glue and decolorizing according to claim 1, characterized in that: The conditions of the reduction decolorization reaction are: reaction temperature is 90 to 140° C., and reaction time is 5 to 60 minutes.

14. The method for removing glue and decolorizing according to claim 1, characterized in that: The oxidative decolorizing solution comprises an oxidant and water, and the oxidant is at least one selected from hydrogen peroxide, sodium nitrate, sodium nitrite, sodium chlorite, calcium chlorite, sodium hypochlorite, calcium hypochlorite, ammonium persulfate and sodium persulfate.

15. The method for removing glue and decolorizing according to claim 1, characterized in that: The concentration of the oxidative decolorizing solution is 0.5 to 15 g / L, and the weight ratio of the oxidative decolorizing solution to the second polyester fabric is 5:1 to 50:

1.

16. The method for removing glue and decolorizing according to claim 1, characterized in that: The conditions of the oxidative decolorization reaction are: reaction temperature is 60 to 120° C., and reaction time is 5 to 60 minutes.

17. The method for removing glue and coloring according to claim 1, characterized in that: The order of the decolorization operation is: firstly, the second polyester fabric is subjected to the reduction decolorization reaction, and then the second polyester fabric subjected to the reduction decolorization reaction is subjected to the oxidation decolorization reaction.

18. The method for removing glue and decolorizing according to claim 1, characterized in that: The order of the decolorization operation is: firstly, the second polyester fabric is subjected to the oxidative decolorization reaction, and then the second polyester fabric subjected to the oxidative decolorization reaction is subjected to the reductive decolorization reaction.

19. The method for removing glue and coloring according to claim 1, further comprising: The third polyester fabric is dried under the following conditions: a drying temperature of 120° C. and a drying time of 2 to 4 hours.

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