Indigo and ring dyeing process using sulfur dye as barrier, and material produced thereby
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional yarn dyeing methods using indigo and sulfur dyes fail to achieve a satisfactory ring dye effect, resulting in inconsistent dye penetration and the need for hazardous chemicals like potassium permanganate to create a worn look.
Innovation Solution
A method involving a sulfur dye barrier applied to the yarn's periphery to minimize dye penetration, using a single sulfur dye bath with specific concentration and pH, followed by controlled immersion and skying times, and subsequent indigo dyeing at optimized pH and time frames to achieve a ring dye effect without core dyeing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional sulfur and indigo dyeing parameters are used, then the yarn becomes dyed, but the dye penetration is inconsistent and the ring dye effect is not achieved
Solution Approach 1:
A sulfur dye barrier is applied to the yarn periphery before indigo dyeing to pre-establish a protective layer that controls subsequent indigo dye penetration depth, ensuring consistent ring dye effect
Solution Approach 2:
The patent optimizes specific parameters including sulfur dye concentration (1-50 grams/liter), immersion time (6-14 seconds), skying time (less than 30 seconds), and indigo dye bath pH (10.8-12.8) to achieve precise control over dye penetration and ring dye effect
2Manufacturing precision
If longer immersion time is used to ensure dye coverage, then the yarn becomes more uniformly dyed, but the core of the yarn also gets dyed losing the ring dye effect
Solution Approach 1:
The sulfur dye barrier is applied in advance to the yarn periphery, creating a protective layer that limits the penetration depth of subsequently applied indigo dye, allowing longer immersion times without compromising the white core
Solution Approach 2:
The sulfur dye acts as an intermediary barrier between the indigo dye and the yarn core, controlling the diffusion of indigo dye molecules and preventing them from reaching the core during extended immersion
3Ease of manufacture
If conventional dyeing methods are used to achieve worn look, then the aesthetic effect is achieved, but hazardous chemicals like potassium permanganate are required
Solution Approach 1:
The patent removes hazardous chemicals like potassium permanganate from the dyeing process by using a controlled sulfur-Indigo ring dyeing method that achieves the desired worn look through precise dye penetration control alone
Solution Approach 2:
The patent converts the potential harm of excessive dye penetration into a benefit by using the sulfur dye barrier to create the desired ring dye effect and worn look without requiring additional hazardous chemicals for correction
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 consistently achieves a ring dye effect with 10% to 35% dye penetration on the yarn's periphery, allowing for a white core and eliminating the need for potassium permanganate, resulting in a more environmentally friendly and consistent dyeing process.
Implementation Method 1
Sulfur dye, once dyed on cellulosic fiber, makes a bigger molecule due to dye and cellulose bonding. The sulfur molecule covers the free sites of cellulose and provides a barrier preventing the indigo dye molecule from traveling towards the core of the yarn
Implementation Method 2
Sulfur dye, once dyed on cellulosic fiber, makes a bigger molecule due to dye and cellulose bonding
Data Source
AI summary
A method of ring dyeing a yarn includes the steps of providing a cellulosic yarn chosen from the group consisting of open-end yarns and ring yarns. The yarn is immersed in only one sulfur dye box, the sulfur dye box having a sulfur concentration of 1 to 50 grams/liter. The yarn is skyed for less than 30 seconds after removal from the sulfur dye box. The yarn is rinsed in water after skying. The yarn is dyed in an indigo dye bath, with the indigo dye bath maintained at a pH of 10.8 and 12.8. The yarn is skyed after removal from the indigo dye box.