Alkaline-Stable Soil Release Polymers with Aromatic Terephthalate Units
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Solution Overview
Problem
Soil release polymers used in alkaline liquid detergents are susceptible to hydrolysis, leading to reduced stability and performance when exposed to alkaline pH conditions, especially in the presence of triethanolamine, which catalyzes the cleavage of ester bonds, resulting in unsatisfactory wash performance.
Innovation Solution
A linear soil release polymer with a specific formula, X-[(EO)q-block-(PO)p]-[(A-R1-A-R2)n-A-R1-A-(PO)p-block-(EO)q]-X, where the PO blocks are adjacent to end ester moieties, hindering hydrolytic attack and enhancing stability, is developed, allowing for incorporation in alkaline detergent liquids with triethanolamine without significant degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional soil release polymers are used in alkaline liquid detergents, then excellent soil release performance is achieved, but the polymers undergo hydrolysis and lose stability during storage
Solution Approach 1:
The patent changes the chemical parameters of the soil release polymer by incorporating aromatic rings (such as terephthalate units) into the polymer backbone. This structural modification increases the polymer's resistance to alkaline hydrolysis while maintaining its soil release performance, resolving the contradiction between reliability and compositional stability.
Solution Approach 2:
The patent creates a composite polymer structure combining aliphatic and aromatic ester units within the same polymer chain. The aromatic segments provide hydrolytic stability while the aliphatic segments maintain soil release functionality, achieving both stability and performance simultaneously.
2Productivity
If triethanolamine is added to boost surfactant performance, then washing performance is improved, but hydrolysis of the soil release polymer is catalyzed
Solution Approach 1:
The patent applies preliminary anti-action by pre-modifying the soil release polymer with aromatic units before exposure to triethanolamine. This structural preparation creates resistance against the catalytic effect of triethanolamine, preventing hydrolysis while allowing the buffer to maintain its performance-boosting function.
3Reliability
If low molecular weight polymers are used, then performance in powder compositions is excellent, but susceptibility to alkaline hydrolysis increases
Solution Approach 1:
The patent changes the chemical composition parameters rather than relying solely on molecular weight. By incorporating aromatic terephthalate units into the polymer structure, the patent achieves hydrolytic stability even at low molecular weights, maintaining both powder composition performance and liquid detergent stability.
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 polymer maintains excellent soil release performance and stability in alkaline conditions, even when stored with triethanolamine, ensuring robust commercial detergent performance by protecting ester bonds from hydrolysis and maintaining fabric substantivity.
Implementation Method 1
the resistance of the SRP to hydrolysis on storage in the detergent liquid at pH from 7.5 to 9.0
Implementation Method 2
The inclusion of Triethanolamine (TEA) in the composition makes matters worse as it appears to catalyse the cleavage of ester bonds present in the SRP
Data Source
AI summary
A linear soil release polymer with the formula (I): X-[(EO)q-block-(PO)p]-[(A-R1-A-R2)n]-A-R1-A-[(PO)p-block-(EO)q] -X (I) where the linking moieties A are esters, where the R1 moieties are 1,4 - phenylene moities, where the R2 moieties are substituted ethylene moieties having C1-4 alkyl substituents and the R2 moieties comprise substituted ethylene moieties derived from the condensation of 2,3 butane diol, where the EO blocks are 100% ethylene oxide (CH2CH2O), where the PO blocks are 100% propylene oxide (CH2CH(CH3)O), where p is a number from 2 to 50, preferably from 5 to 45, more preferably from 6 to 40, yet more preferably from 7 to 40 and most preferably from 8 to 40, even from 1 1 to 35; where q is a number from 6 to 120, preferably 18 to 80, most preferably 40 to 70, provided that q is greater than p and preferably q is at least 1.5 times as large as p; where X is a suitable capping moiety, preferably selected from C1-4 alkyl, branched and unbranched; where n is a number from 2 to 16.