Single-Bath Dyeing of Polyester-Nylon Nonwoven Fabrics
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Solution Overview
Problem
Nonwoven fabrics, used for apparel, face challenges in achieving uniform color and colorfastness due to their unique construction and varying fiber types, which require multiple dyeing steps and different dye affinities, lacking established dyeing and colorfastness standards.
Innovation Solution
A method involving a single dye bath solution combining disperse dye for polyester and acid dye for nylon, with citric acid to adjust pH, applied at a higher temperature than conventional methods, followed by a specific dyeing and rinsing process to achieve uniform color and high colorfastness, using a formulation where dye percentages match fiber weights and a fixing agent to secure the dyes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple dye baths are used for different fiber types, then each fiber type can be dyed with appropriate dye, but the dyeing process complexity and time increase
Solution Approach 1:
The patent combines multiple dye baths into a single dye bath that contains both disperse dye for polyester and acid dye for nylon. This merging approach allows simultaneous dyeing of different fiber types in one process step, achieving color uniformity across mixed fiber nonwoven fabrics without requiring separate dyeing operations for each fiber type.
Solution Approach 2:
The single dye bath formulation achieves multi-functionality by accommodating both polyester and nylon fibers with different dye affinities. The dye bath contains disperse dye components for polyester uptake and acid dye components for nylon uptake, allowing one dyeing process to serve multiple fiber types that would traditionally require separate specialized dye baths.
2Manufacturing precision
If multiple dyeing steps are used for different fiber types, then appropriate dyes can be applied to each fiber, but the production time and cost increase
Solution Approach 1:
The patent merges sequential multiple dyeing steps into a single simultaneous dyeing operation. The single dye bath contains all necessary dye components (disperse dye for polyester, acid dye for nylon) that are applied together in one process step, eliminating the need for sequential dyeing operations and significantly reducing production time while maintaining colorfastness.
Solution Approach 2:
The dyeing process maintains continuous useful action by having both polyester and nylon fibers uptake their respective dyes simultaneously in one continuous process step. This eliminates idle time between sequential dyeing operations and keeps the dyeing action continuous and productive throughout the process.
3Manufacturing precision
If higher temperature dyeing is used, then dye penetration and uniformity improve, but energy consumption and fiber damage risk increase
Solution Approach 1:
The patent utilizes parameter changes by raising the dyeing temperature to higher levels (e.g., 200-250°C or higher) to enhance dye penetration and achieve superior color uniformity across different fiber types. The single dye bath formulation is specifically designed to withstand and utilize these elevated temperatures to improve dye uptake kinetics and uniformity for both polyester and nylon fibers.
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 results in a nonwoven fabric with high color uniformity and colorfastness, rated between Grade 4 and Grade 5 in industry standards, indicating minimal color loss and shade differences, and negligible crocking, suitable for apparel applications.
Implementation Method 1
A method is disclosed for dyeing a nonwoven fabric construction comprising different fiber/yarn types, such as polyester and nylon, in a single dye bath solution
Implementation Method 2
combining disperse dye for polyester and acid dye for nylon
Implementation Method 3
with citric acid to adjust pH
Implementation Method 4
a fixing agent to secure the dyes
Data Source
AI summary
A method is provided for dyeing a nonwoven fabric comprising a blend of fibers to a single color shade. The method includes selecting a nonwoven fabric formed of a blend of polyester and nylon fibers, where the polyester fibers comprise about X percent by weight of the fabric and the nylon fibers comprise about Y percent by weight of the fabric. A single bath is formulated having about X percent by weight disperse dye and about Y percent by weight acid dye, adjusted for the desired color shade/depth. The nonwoven fabric is then dyed to obtain a dyed fabric having a single color shade of at least Grade 4 when measured in accordance with AATCC Test Method 153 and a colorfastness of at least Grade 4 when measured in accordance with AATCC Test Method 61.