Method for decolorizing polyester fabric
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Solution Overview
Problem
Existing methods for recycling polyester fabrics are inadequate as they fail to effectively remove both dyes and water repellents, leading to poor recycling quality and limited applications due to residual impurities.
Innovation Solution
A decolorization method using a composite solvent composed of propylene glycol methyl ether (PM) and acetic acid, which is applied to a dyed polyester fabric at a temperature higher than its glass transition temperature to extract both dyes and water repellents, thereby producing a high-quality recycled fabric.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional solvent extraction methods are used, then dye removal efficiency is improved, but water repellent removal is insufficient
Solution Approach 1:
The patent uses a composite solvent system consisting of propylene glycol methyl ether and acetic acid in a specific weight ratio (95:5 to 5:95). This composite solvent combines the dye-solving capability of propylene glycol methyl ether with the water repellent-dissolving capability of acetic acid, enabling simultaneous removal of both impurities from polyester fabric
Solution Approach 2:
The patent optimizes the weight ratio parameters of the composite solvent components and controls the extraction temperature parameter (heating to enhance extraction efficiency). By adjusting these parameters, the solvent system achieves optimal performance for removing both dye and water repellent
2Productivity
If high-temperature extraction is used to improve extraction efficiency, then energy consumption increases
Solution Approach 1:
The patent utilizes the glass transition temperature of polyester fabric as a reference parameter, heating the composite solvent to a temperature higher than the glass transition temperature of the polyester fabric. This optimized temperature parameter achieves effective extraction of both dye and water repellent while avoiding excessive energy consumption that would result from much higher temperatures
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method achieves efficient removal of dyes and water repellents, resulting in a recycled polyester fabric with a significantly reduced water repellent content (not greater than 200 ppm) and improved recycling quality.
Implementation Method 1
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
Implementation Method 2
the composite solvent is heated to an extraction temperature, so as to wet the polyester fabric and remove the dye and the water repellent from the material of the polyester fabric by extraction
Data Source
AI summary
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.