Method of continuous dyeing with reactive dyes in wet conditions
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Solution Overview
Problem
Conventional reactive dyeing processes for cellulose fibers are inefficient, requiring large amounts of inorganic salt, alkali, and steam, with complex procedures and poor reproducibility, leading to high costs and quality fluctuations.
Innovation Solution
A continuous dyeing method involving a one-bath-one-step process with an activated dye liquor and color-fixation alkali, using an air film horizontal pad dyeing machine for preheating and rolling, which reduces steam consumption and eliminates free water, allowing for controlled moisture content and temperature adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the conventional pad-dry-pad-steam dyeing process is used, then the reactive dyeing of cellulose fibers can be achieved, but the process consumes large amounts of inorganic salt, alkali, and steam, and the procedure becomes long and complex
Solution Approach 1:
The patent combines multiple separate operations (padding, drying, padding again, steaming) into a single continuous wet-on-wet dyeing process. The fabric passes through multiple padding baths sequentially without intermediate drying, merging what were previously distinct process stages into one integrated operation, thereby simplifying the overall process while maintaining dyeing effectiveness
Solution Approach 2:
The invention implements a continuous dyeing process where fabric moves continuously through multiple padding baths and fixation zones without interruption. This eliminates the batch-wise operations and idle times associated with conventional pad-dry-pad-steam cycles, maintaining continuous useful action throughout the dyeing process to improve efficiency and reduce complexity
2Reliability
If the conventional pad-dry-pad-steam dyeing process is used, then the reactive dyeing of cellulose fibers can be achieved, but the process procedure becomes long and costly
Solution Approach 1:
The patent skips the intermediate drying step between padding operations that characterizes conventional processes. By proceeding directly from the first padding bath to the second padding bath while the fabric is still wet, the process eliminates unnecessary time-consuming drying cycles and accelerates the overall dyeing operation while achieving the same or better dyeing results
3Ease of manufacture
If the cold pad-batch process with multiple alkali components is used, then the dyeing can be performed, but the dyeing reproducibility is poor and quality fluctuations are large
Solution Approach 1:
The patent changes the chemical parameters of the dyeing system by using a single standardized alkali solution (sodium hydroxide at controlled concentration and temperature) instead of multiple varying alkali components. This parameter standardization ensures consistent chemical conditions throughout the process, improving reproducibility while maintaining feasibility
Solution Approach 2:
The invention applies different functional solutions to different stages of the dyeing process: the first padding bath contains the reactive dye, the second padding bath contains the standardized alkali for fixation, and subsequent baths handle washing and finishing. Each stage has optimized local conditions, with particular attention to uniform alkali distribution in the fixation bath to ensure consistent results
4Reliability
If the conventional processes are used, then the dyeing can be completed, but steam consumption is high and energy efficiency is low
Solution Approach 1:
The patent replaces the thermal steam fixation mechanism with a chemical fixation mechanism using aqueous alkali. Instead of using steam to activate and fix the reactive dye, the process uses controlled alkali treatment in the second padding bath, eliminating the need for steam input and dramatically reducing energy consumption while achieving effective dye fixation
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 shortens the dyeing process, reduces inorganic salt usage, enhances dye fixation and color depth, prevents seam defects, and improves energy efficiency while maintaining high color fastness and reproducibility.
Implementation Method 1
adding fabric to a mixture of a dye liquor and an alkali through a one-bath-one-step method
Implementation Method 2
preheating the fabric after being treated in 2) at a temperature of 50-90° C.
Implementation Method 3
the moisture content of the preheated fabric is 15-30%, and the fabric contains no free water
Data Source
AI summary
The disclosure provides a method of continuous dyeing with reactive dyes in wet conditions, the method including: 1) adding fabric to a mixture of a dye liquor and an alkali through a one-bath-one-step method; 2) immersing the fabric pretreated in 1) in a padding liquor with an air film horizontal pad dyeing machine; 3) preheating the fabric after being treated in 2) at a temperature of 50-90° C.; and 4) rolling and batching the fabric after being treated in 3) at a temperature of 10-70° C. for 2-72 hours.