Spun-dyed fiber and method for its manufacture
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Solution Overview
Problem
Existing spun-dyed cellulosic fibers experience significant pigment bleeding during downstream processing, particularly with dark colors like carbon black, and current methods are inefficient, environmentally harmful, and economically unfeasible.
Innovation Solution
A spun-dyed man-made cellulosic fiber with a polycationic compound on its outer surface, such as poly(diallyldimethylammonium chloride), is developed to enhance pigment fixation, reducing bleeding and processing time, and minimizing waste.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If pigment is incorporated into spinning dope before fiber formation, then dyeing efficiency is improved and ecological footprint is reduced, but pigment bleeding occurs during downstream processing
Solution Approach 1:
A polycationic compound acts as an intermediary between the negatively charged pigment particles and the cellulosic fiber, forming a bridge that secures the pigment to the fiber surface. The polycationic compound creates electrostatic attraction with both the pigment and the fiber, preventing pigment bleeding during downstream processing while maintaining the spin-dyeing efficiency benefits.
Solution Approach 2:
The invention changes the surface charge parameter of the fiber by introducing polycationic compounds, transforming the normally negative surface charge to positive. This parameter change enables electrostatic binding of negatively charged pigments to the fiber surface, effectively preventing pigment bleeding while maintaining the incorporated coloration benefits.
2Reliability
If polycationic compounds are incorporated during fiber manufacture, then pigment fixation is improved, but spinnability of spinning solution deteriorates due to early coagulation
Solution Approach 1:
Instead of incorporating polycationic compounds throughout the entire spinning solution (which would cause early coagulation), the invention applies them locally to the fiber surface after fiber formation. This localized application achieves effective pigment fixation while avoiding interference with the spinning process.
Solution Approach 2:
The fiber is first formed through the spinning process, then the polycationic compound is applied in a preliminary treatment step before the pigment incorporation or downstream processing. This sequence ensures the fiber structure is established first, then the surface is prepared for optimal pigment binding without affecting spinnability.
3Object-generated harmful factors
If harsh washing conditions are applied to remove surplus pigment, then pigment bleeding is reduced, but processing time increases and ecological feasibility deteriorates
Solution Approach 1:
The polycationic compound is applied to the fiber surface before pigment incorporation or downstream processing, creating a binding layer that prevents pigment bleeding from the outset. This preliminary action eliminates the need for harsh post-processing washing steps, reducing both time and environmental impact.
Solution Approach 2:
The invention converts the potential harm of pigment bleeding into a benefit by using the polycationic compound to create controlled electrostatic binding. This allows mild washing conditions to be used effectively, as the pigment is already secured to the fiber, transforming what would require harsh treatment into a gentle process.
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 fiber achieves reduced pigment bleeding and shorter processing times, maintaining positive zeta potential for effective pigment retention across various pH levels, with improved ecological and economic feasibility.
Implementation Method 1
a spun-dyed man-made cellulosic fiber with incorporated color pigment which contains a polycationic compound on its outer surface
Data Source
Figure 1~2
AI summary
This invention relates to a spun-dyed man-made cellulosic fiber with incorporated color pigment which contains a polycationic compound on its outer surface. Furthermore a method for the manufacture of such a fiber is disclosed.