Alkaline-Stable Polyester Soil Release Agents
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Solution Overview
Problem
Existing polyesters used as soil release agents in laundry detergents often suffer from instability in alkaline environments, leading to turbidity and loss of soil release power in heavy-duty washing liquids.
Innovation Solution
Development of polyesters with a specific molecular structure, characterized by blockwise arrangement of ethylene and propylene oxide groups, which are soluble in alkaline compositions and stable under alkaline conditions, prepared through a two-step process involving dimethyl terephthalate, 1,2-propylene glycol, and a catalyst system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional polyesters are used as soil release agents, then they provide soil release function, but they show turbidity and lose stability in alkaline heavy duty washing liquids
Solution Approach 1:
The patent changes the chemical parameters of the polyester by introducing specific structural features: incorporating 20-50 mol% terephthalic acid units and 5-30 mol% alkylene oxide units (ethylene oxide and/or propylene oxide) to create a polyester with modified solubility and stability characteristics that resist turbidity and hydrolysis in alkaline environments
Solution Approach 2:
The patent creates a composite polyester structure by combining multiple structural units (terephthalic acid units, alkylene oxide units, and other dicarboxylic acid/polyol units) to achieve synergistic effects that provide both soil release functionality and enhanced stability in alkaline heavy duty washing liquids
2Reliability
If polyesters are made more stable in alkaline environment, then stability improves, but solubility in alkaline compositions may be compromised
Solution Approach 1:
The patent optimizes the compositional parameters by controlling the molar percentages of different structural units: 20-50 mol% terephthalic acid units provide stability, while 5-30 mol% alkylene oxide units maintain solubility in alkaline compositions, achieving a balanced formulation that satisfies both requirements simultaneously
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 new polyesters exhibit improved stability and solubility in alkaline solutions, maintaining effective soil release properties and foam suppression, even after storage, enhancing washing performance and reducing foaming.
Implementation Method 1
The polyesters are e.g. useful as soil release agents in laundry detergent and fabric care products... materials that modify the fabric surface minimizing the subsequent soiling
Implementation Method 2
EP 1 661 933 A1 discloses soil release oligoesters... amphiphilic and nonionic oligoesters prepared by reacting dicarboxylic acid compounds, polyol compounds and water-soluble alkylene oxide adducts
Data Source
AI summary
Polyesters according to the following formula (I) are described formula (I) wherein R1 and R2 independently of one another are X-(OC2H4)n-(OC3H6)m wherein X is C1-4 alkyl, the -(OC2H4) groups and the -(OC3H6) groups are arranged blockwise and the block consisting of the -(OC3H6) groups is bound to a COO group or are HO-(C3H6), n is based on a molar average a number of from 12 to 120, m is based on a molar average a number of from 1 to 10, and a is based on a molar average a number of from 4 to 9. The inventive polyesters have an advantageous stability in alkaline environment, possess a beneficial solubility and advantageously are clearly soluble in alkaline compositions such as alkaline heavy duty washing liquids and also possess advantageous soil release properties.