Abstract: The disclosure provides a decolorization and purification method of BHET material, which includes the following steps. A first dose of activated carbon is added to preliminarily treat the BHET material. After the preliminary treatment, a first cooling crystallization process and filtration are performed to obtain BHET crystals. Afterwards, an oxidant is used to chemically react with the BHET crystals to destroy a dye or impurities, and then a second dose of activated carbon is added to adsorb a chemically reacted oxide. Next, a second cooling crystallization process, filtration, and drying are performed to obtain a finished product of BHET.

Abstract: A method for manufacturing polyester polyhydric alcohol is provided. The method for manufacturing the polyester polyhydric alcohol includes steps as follows. A polybasic acid and a first polyhydric alcohol are mixed for a first oligomerization reaction, so as to form a first oligomer mixture. A second polyhydric alcohol is added into the first oligomer mixture for a second oligomerization reaction when a remaining amount of the first polyhydric alcohol in the first oligomer mixture is lower than or equal to 1 mol %, so as to form a second oligomer mixture. A catalyst is added into the second oligomer mixture for a polycondensation reaction, so as to obtain a polyester polyhydric alcohol product. The polyester polyhydric alcohol product has an Alpha value of lower than 30.

Abstract: The disclosure provides a decolorization and purification method of BHET material, which includes the following steps. A first dose of activated carbon is added to preliminarily treat the BHET material. After the preliminary treatment, a first cooling crystallization process and filtration are performed to obtain BHET crystals. Afterwards, an oxidant is used to chemically react with the BHET crystals to destroy a dye or impurities, and then a second dose of activated carbon is added to adsorb a chemically reacted oxide. Next, a second cooling crystallization process, filtration, and drying are performed to obtain a finished product of BHET.

Abstract: A disposal method for waste fabric containing polyester, nylon, and dye includes the following steps: step (a): providing a waste fabric containing polyester, nylon, and dye; and step (b): performing a first-stage treatment including acid treatment on the waste fabric to obtain a first liquid material and a first solid material. The first-stage treatment includes acid treatment with an acid liquid mixed with an oxidant. The first solid material includes recycled polyester, and/or the first liquid material includes recycled nylon or degraded nylon.

Abstract: A method for processing a waste fabric containing polyester and cotton fibers includes the following steps. The first step is providing a plurality of fabric scraps each containing polyester fibers and cotton fibers. The next step is allowing an acid catalyst aqueous solution to repeatedly contact and react with the fabric scraps at 130° C. to 160° C. in a circulation and backflow manner, so as to separate the cotton fibers from each of the fabric scraps. The last step is recycling the reacted acid catalyst aqueous solution and fabric scraps.

Abstract: A disposal method for waste fabric containing polyester, spandex, and dye includes the following steps: step (a): providing a waste fabric containing polyester, spandex, and dye; and step (b): performing a first-stage treatment including elution on the waste fabric to obtain a first liquid material and a first solid material. The first-stage treatment includes elution with a cosolvent mixed with an oxidant. The first solid material includes recycled polyester, and/or the first liquid material includes recycled spandex or degraded spandex.

Abstract: A method for recycling a polyester fabric is provided. The method includes providing a polyester fabric that is dyed and has dye and water repellent attached thereon, providing a composite solvent containing water and acetic acid mixed with each other, performing an extraction operation including infiltrating the polyester fabric with the composite solvent and extracting the dye and the water repellent, and carrying out a liquid state polycondensation reaction on the polyester fabric so that an intrinsic viscosity of the polyester fabric is increased and residual impurities of the polyester fabric are further removed.

Abstract: A method for decolorizing a polyester fabric is provided, which includes: providing a dyed polyester fabric, in which a material of the dyed polyester fabric contains a dye and a water repellent; providing a composite solvent, in which the composite solvent includes propylene glycol methyl ether (PM) and acetic acid that are mixed together; and performing an extraction process, which includes using the composite solvent to wet the dyed polyester fabric and remove the dye and the water repellent from the material of the polyester fabric by extraction, so as to obtain a reduced polyester fabric.

Abstract: A method for improving a recovery rate of recycled bis(2-hydroxyethyl) terephthalate (BHET) is provided, which includes: providing a recycled polyester fabric; using a chemical de-polymerization liquid to chemically depolymerize the recycled polyester fabric, so as to form a de-polymerization product containing BHET; dissolving the BHET in water to form a aqueous phase liquid; cooling the aqueous phase liquid from a dissolution temperature to a first crystallization temperature, so as to crystallize at least a part of the BHET; and cooling the aqueous phase liquid from the first crystallization temperature to a second crystallization temperature, so as to crystallize at least another part of the BHET.

Abstract: Provided is a recycling method of a polyester cotton blended fabric, including the following steps. A dye-containing polyester cotton blended fabric is put into an acidic aqueous solution containing an oxidizing agent for heating and soaking, so as to degrade the cotton in the polyester cotton blended fabric into powder, and decolorization is performed at the same time to remove the dye. After that, a polyester fabric and cotton powder are obtained by double filtration.

Abstract: A method for producing recycled polyester chips from a recycled polyester fabric is provided. The method includes: providing the recycled polyester fabric attached with dyes and/or coating glue; performing a color removal process to at least partially remove the dyes and/or the coating glue attached to the polyester fabric; performing a de-polymerization process which includes: using a chemical de-polymerization liquid to chemically depolymerize the recycled polyester fabric, so as to form a de-polymerization product containing bis(2-hydroxyethyl) terephthalate (BHET) and oligomers; performing a purification process, so as to enhance a purity of the BHET in the de-polymerization product; and performing a granulation process, so as to re-polymerize the purified BHET and form the recycled polyester chips (r-PET).

Abstract: A decolorization method of a polyester fabric includes: providing a polyester fabric, in which the polyester fabric is a dyed polyester fabric and the polyester fabric is adhered with a dye and has a first L value; providing a first decolorizing solution and a second decolorizing solution, in which the first decolorizing solution contains a reductant and the second decolorizing solution contains an oxidant; and performing a decolorization process which includes: using one of the first decolorizing solution and the second decolorizing solution to decolorize one portion of the dye and using another one of the first decolorizing solution and the second decolorizing solution to decolorize another portion of the dye, so that a color of the dye is removed and the polyester fabric is white in color and has a second L value that is greater than the first L value.

Abstract: A method for improving the hue of recycled BHET is provided. The method includes: providing a recycled polyester fabric; using a chemical de-polymerization liquid to chemically depolymerize the recycled polyester fabric to form a de-polymerization product; distilling out the chemical de-polymerization liquid from the de-polymerization product by evaporation; dissolving the BHET in water to form a aqueous phase liquid; adding an activated carbon material to the aqueous phase liquid to adsorb impurities; and cooling the aqueous phase liquid to crystallize the BHET from the aqueous phase liquid to obtain a recycled BHET.

Abstract: Provided is a recycling method of polyester wool blended fabric, which includes the following. A polyester wool blended fabric containing a dye is put into an acidic aqueous solution containing an oxidizing agent for heating and soaking, so as to degrade a wool in the polyester wool blended fabric, and perform decolorization at the same time to remove the dye. After that, a polyester fabric is obtained by filtration.

Abstract: A method for recycling polyester fabrics with use of an ionic liquid catalyst is provided, which includes: providing a recycled polyester fabric; and using a chemical de-polymerization liquid to chemically de-polymerize the recycled polyester fabric and form a de-polymerization product that includes bis-2-hydroxylethyl terephthalate (BHET). The chemical de-polymerization liquid is used to chemically de-polymerize the recycled polyester fabric in an environment where a de-polymerization catalyst exists, and the de-polymerization catalyst is the ionic liquid catalyst in a solid state.

Abstract: A method for improving hue of recycled bis-2-hydroxylethyl terephthalate by using ionic liquids including providing a recycled polyester fabric; using a chemical de-polymerization liquid to chemically de-polymerize the recycled polyester fabric to form a de-polymerization product; mixing the de-polymerization product with water to form an aqueous phase liquid; dispersing an ionic liquid impurity adsorption material into the aqueous phase liquid to adsorb impurities originally present in the recycled polyester fabric.

Abstract: A decolorization method for a dyed fiber cloth is provided. The decolorization method for the dyed fiber cloth includes steps of: providing a fiber cloth attached with a dye, extracting the dye attached on the fiber cloth by an extractant, and applying a microwave to evaporate the extractant so as to obtain a dried and decolored fiber cloth.

Abstract: A method for manufacturing polyester polyhydric alcohol is provided. The method for manufacturing polyester polyhydric alcohol includes steps as follows. A polybasic acid and a polyhydric alcohol are mixed for oligomerization to form an oligomer mixture. A catalyst is added into the oligomer mixture at a temperature ranging from 190° C. to 210° C. for polycondensation to obtain a polyester polyhydric alcohol product. The polyester polyhydric alcohol product has a number average molecular weight lower than 1000 g/mol and an acid value lower than or equal to 0.3 mg KOH/g.

Abstract: A method for manufacturing polyester polyhydric alcohol is provided. The method for manufacturing the polyester polyhydric alcohol includes steps as follows. A polybasic acid and a first polyhydric alcohol are mixed for a first oligomerization reaction, so as to form a first oligomer mixture. A second polyhydric alcohol is added into the first oligomer mixture for a second oligomerization reaction when a remaining amount of the first polyhydric alcohol in the first oligomer mixture is lower than or equal to 1 mol %, so as to form a second oligomer mixture. A catalyst is added into the second oligomer mixture for a polycondensation reaction, so as to obtain a polyester polyhydric alcohol product. The polyester polyhydric alcohol product has an Alpha value of lower than 30.

Abstract: A plasticizer and a method for producing the same are provided. The method for producing the plasticizer includes: reacting a reaction mixture at each of a plurality of temperature holding stages in a heating process to form a semi-finished product; and purifying the semi-finished product at each of a plurality of low pressure stages of a decompression process to obtain a plasticizer. A temperature range of the heating process is from 140° C. to 220° C., a pressure range of the decompression process is from 750 Torr to 20 Torr, and the reaction mixture contains dibasic acid, diol, monohydric alcohol, and catalyst.