Textile Decoloring Using Anionic Polyelectrolytes in Alkaline Solution
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing textile recycling processes face inefficiencies and complexity in decoloring textile materials, particularly when dealing with both dyed and pigmented materials.
Innovation Solution
A method involving treatment of textile materials in an alkaline solution containing one or more anionic polyelectrolytes, such as carboxymethyl cellulose (CMC), at elevated temperatures for a minimum of 10 minutes, effectively decoloring both dyed and pigmented textiles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional decoloring processes are used, then textile materials can be decolored, but the process is either not efficient or involves several process steps and chemicals making the recycling process complex
Solution Approach 1:
The patent combines decoloring and fiber separation functions into a single treatment step using one alkaline solution containing CMC and NaOH, eliminating the need for separate decoloring and separation processes. This integration directly reduces process complexity while maintaining high decoloring efficiency.
Solution Approach 2:
The alkaline solution with CMC serves multiple functions simultaneously: it acts as a decoloring agent for both dyed and pigmented textiles, a separating medium for different fiber types, and a treatment medium that can be reused. This multi-functionality resolves the contradiction by achieving efficient decoloring without adding process steps.
2Adaptability or versatility
If conventional decoloring methods are applied, then textile materials can be treated, but the process does not effectively handle both dyed and pigmented materials simultaneously
Solution Approach 1:
The patent uses specific parameter combinations (pH 12-14, temperature 80-200°C, CMC concentration 0.1-5%) that create optimal conditions for decoloring both dyed and pigmented textiles. The strong alkaline environment combined with CMC's chelating ability allows universal effectiveness across different textile types while maintaining high decoloring efficiency.
Solution Approach 2:
CMC acts as an intermediary substance that facilitates decoloring through its chelating properties, binding to metal ions in both dye and pigment molecules. This intermediary mechanism enables the solution to effectively treat diverse textile colorings without requiring different process conditions.
3Manufacturing precision
If multiple process steps and chemicals are used for decoloring, then thorough decoloring can be achieved, but the recycling process becomes complex
Solution Approach 1:
The patent merges decoloring chemicals (CMC and NaOH) and functions into a single treatment bath, achieving complete decoloring without requiring multiple sequential steps. The synergistic interaction between CMC's chelating action and NaOH's alkaline environment provides thorough decoloring in one step.
Solution Approach 2:
The treatment solution is a composite system combining CMC (a polysaccharide with chelating groups) and NaOH (a strong base). This composite chemical system provides multiple decoloring mechanisms simultaneously, achieving complete decoloring while simplifying the process to a single step.
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
This method significantly improves decoloring efficiency, allowing for simultaneous decoloring and separation of cellulosic and polyester fibers, thus simplifying the recycling process.
Implementation Method 1
the presence of an anionic polyelectrolyte in the alkaline solution, such as carboxymethyl cellulose (CMC), significantly improves decoloring of textile materials
Implementation Method 2
treating the textile material in the alkaline solution during a treatment period of at least 10 minutes at a temperature in the range of from 100°C to 180°C
Implementation Method 3
separation of cellulosic material from polyester material
Implementation Method 4
By adding an anionic polyelectrolyte, such as CMC, to the alkaline solution of WO2020/013755, separation of cellulosic fibers from polyester fibers as well as decoloring of colored fibers can be carried out simultaneously
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The invention concerns a method for decoloring of a textile material, the method comprising the steps of: providing a textile material; providing an alkaline solution containing one or more anionic polyelectrolytes; treating the textile material in the alkaline solution during a treatment period; and recovering at least some of the textile material from the alkaline solution.