Acid Donor Composition for Stable Polyamide Dyeing pH Control
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Solution Overview
Problem
Existing acid donors used in textile dyeing processes, such as formic acid esters of polyethylene glycol or polypropylene glycol, are susceptible to hydrolysis and decompose during storage, leading to instability and reduced effectiveness in maintaining pH levels during dyeing.
Innovation Solution
A homogeneous anhydrous liquid formulation comprising a C1-C2 carboxylic acid ester and an N-heterocyclic compound with a pKa value of 6 to 8 is developed, which significantly reduces hydrolysis tendencies and enhances storage stability, allowing for better pH control in textile-processing processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If formic acid esters of polyethylene glycol or polypropylene glycol are used as acid donors, then pH-regulating properties are achieved, but storage stability deteriorates due to hydrolysis and decomposition
Solution Approach 1:
The patent introduces N-heterocyclic compounds as intermediary substances that mediate between the acid donor and the environment. These compounds form stable complexes with the formic acid esters, preventing direct exposure to hydrolytic conditions while maintaining pH-regulating functionality. The N-heterocyclic compound acts as a protective intermediary layer that stabilizes the acid donor during storage.
Solution Approach 2:
The invention creates a composite acid donor system by combining formic acid esters with N-heterocyclic compounds. This composite formulation integrates the pH-regulating capability of the ester with the stabilizing properties of the heterocyclic compound, resulting in a material that maintains both functionality and storage stability. The composite structure prevents decomposition while preserving the desired chemical properties.
2Manufacturing precision
If acid donors are added to dyeing liquor, then uniform pH control is achieved, but hydrolysis and decomposition occur during storage
Solution Approach 1:
N-heterocyclic compounds serve as intermediary agents that protect the acid donor from premature hydrolysis during storage. The heterocyclic compound forms a stable complex with the formic acid ester, acting as a protective barrier that prevents water from attacking the ester bond. This intermediary protection maintains the acid donor's integrity until it is actually used in the dyeing process.
Solution Approach 2:
The invention changes the chemical parameters of the acid donor system by introducing N-heterocyclic compounds with specific pKa values (6-8). This parameter change modifies the overall stability profile of the formulation, creating a system that resists hydrolysis at storage conditions while maintaining pH-regulating capability at dyeing temperatures. The heterocyclic compound's basicity parameters counterbalance the ester's susceptibility to hydrolysis.
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 formulation provides improved storage stability and uniform pH control during textile dyeing, resulting in more consistent and level dyeing outcomes, even at elevated temperatures.
Implementation Method 1
the tendency of certain carboxylic acid ester formulations towards hydrolysis can be substantially reduced by the addition of N-heterocyclic compounds
Implementation Method 2
acid donors are frequently added to the dyeing liquor, which hydrolyse in the course of the dyeing process and, in so doing, release an acid, resulting in a slow reduction in pH
Data Source
AI summary
An adjuvant composition comprising (A) a C1-C2carboxylic acid ester of a polyhydroxy compound containing from 2 to 20 hydroxyl groups and (B) an N-heterocyclic compound having a pKa, value of from 6 to 8 is storage-stable and suitable as an acid donor in the dyeing of polyamides.