Low-VOC Ionic Dye Carriers for Hydrophobic Aramid Fiber Dyeing
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Solution Overview
Problem
Aromatic polyamides (aramids) are hydrophobic and difficult to dye using standard aqueous dye formulations due to their low penetrability, and existing dye carriers with high vapor pressure and VOC emissions pose environmental and health concerns.
Innovation Solution
Dye formulations using non-volatile dialkyl imidazolium salts and bis-quaternary amine salts as dye carriers, combined with additives like 1-phenoxy-2-propanol, facilitate dye penetration in aramid fibers at controlled pH and temperature, reducing VOC emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If standard aqueous dye formulations are used, then the dyeing process is simple, but the dye cannot penetrate into the hydrophobic aramid fibers
Solution Approach 1:
The patent introduces a dye carrier as an intermediary substance that mediates between the aqueous dye solution and the hydrophobic aramid fibers. The dye carrier has dual affinity: it is hydrophilic enough to dissolve in water and hydrophobic enough to penetrate the aramid fibers, thereby enabling dye transfer. This resolves the contradiction by providing a bridge that allows effective dye penetration without requiring complex modification of the aramid fibers or the dye itself.
Solution Approach 2:
The patent modifies the chemical parameters of the dyeing system by introducing a dye carrier with specific molecular structure and properties. The dye carrier changes the physical-chemical parameters of the dye solution, enabling it to interact with hydrophobic aramid fibers. This parameter change allows standard aqueous dye formulations to effectively dye aramids without fundamentally altering the dyeing process complexity.
2Reliability
If traditional dye carriers with high vapor pressure are used, then dye penetration is effective, but VOC emissions and toxicity increase
Solution Approach 1:
The patent changes the key parameter of the dye carrier from high vapor pressure to low or negligible vapor pressure. By selecting ionic liquids and other non-volatile compounds as dye carriers, the patent maintains effective dye penetration capability while eliminating VOC emissions and reducing toxicity. This parameter change directly resolves the contradiction between effectiveness and environmental safety.
Solution Approach 2:
The patent replaces traditional volatile organic dye carriers with non-volatile ionic liquids that can be reused and do not evaporate. This substitution eliminates the harmful emissions associated with traditional carriers while maintaining their dyeing effectiveness, thereby resolving the contradiction between performance and environmental impact.
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 formulations achieve effective dyeing of aramid fibers with improved color retention and reduced environmental impact, outperforming traditional dye carriers in terms of color intensity and pH stability.
Implementation Method 1
The dye carrier facilitates penetration of the dye throughout the aramid fibers
Implementation Method 2
an aqueous dye solution containing a dye carrier that swells constituent fibers
Data Source
AI summary
Compositions and methods for dyeing aramids include one or more dye carriers selected from dialkyl imidazolium salts having a cation of the general formula: where R1 and R2 are, independently, selected from C1 to C8 alkyl, and bis-quaternary amine salts having a cation of the formula: where R1 is, independently at each instance, a C1-C6 alkyl; R2 and R3 are, independently at each instance, a C1-C6 alkyl or substituted C1-C6 alkyl, and X is, independently at each instance, a halogen; and one or more cationic dyes.