Fabric Softener Ester Composition for Solvent-Free Stability
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Solution Overview
Problem
Existing fabric softener actives face challenges with high melting points and limited thermal and hydrolytic stability, requiring solvents for processing and leading to instability in aqueous dispersions, especially at elevated temperatures.
Innovation Solution
A fabric softener composition comprising bis-(2-hydroxypropyl)-dimethylammonium methylsulphate fatty acid ester with a specific molar ratio of fatty acid to amine, average chain length, and iodine value, along with a controlled amount of free fatty acid, which allows for solvent-free processing and improved stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional ester quats are used to achieve high softening performance, then fabric softening performance is improved, but storage stability in aqueous dispersion deteriorates due to viscosity increase and settling at elevated temperatures
Solution Approach 1:
The patent applies parameter changes by modifying the chemical structure of ester quats - specifically using bis-(2-hydroxypropyl)-dialkylammonium salts with controlled fatty acid chain lengths (C12-C20) and degrees of unsaturation (iodine value 50-200). These structural parameter changes result in submicrometer particle dispersions that maintain stable viscosity and prevent settling at elevated temperatures, resolving the storage stability issue while preserving softening performance
Solution Approach 2:
The invention creates a composite system by formulating aqueous dispersions containing submicrometer particles of bis-(2-hydroxypropyl)-dialkylammonium salt fatty acid diesters combined with specific surfactants and stabilizers. This composite approach enhances dispersion stability and prevents aggregation during storage, addressing the stability deterioration problem
2Reliability
If fabric softener actives with high melting points are used to achieve desired softening performance, then softening performance is improved, but ease of processing deteriorates due to requirement of volatile solvents
Solution Approach 1:
The patent extracts and eliminates the need for volatile solvents (ethanol, isopropanol) from the formulation by developing aqueous dispersions of bis-(2-hydroxypropyl)-dialkylammonium salt fatty acid diesters. The active substance is delivered in a solvent-free or water-based form, removing the flammability hazard and simplifying processing while maintaining effective softening performance
Solution Approach 2:
The invention changes the physical state parameters of the fabric softener active by formulating it as submicrometer particles in aqueous dispersion rather than as high-melting solids requiring solvent dissolution. This parameter change from solid to dispersed particulate form enables direct processing without volatile solvents while preserving the softening functionality
3Ease of operation
If fabric softener actives are delivered with 5 to 15 % by weight ethanol or isopropanol to enable processing, then ease of processing is improved, but safety deteriorates due to volatility and flammability of the solvent
Solution Approach 1:
The patent removes the harmful volatile solvent component (ethanol or isopropanol) from the fabric softener formulation by developing aqueous dispersions of bis-(2-hydroxypropyl)-dialkylammonium salt fatty acid diesters. The active substance can be handled and processed in its pure form or in water-based dispersions, eliminating flammability hazards while maintaining processing ease through the liquid dispersion state
Solution Approach 2:
The invention converts the potential harm of high melting points and poor processability into a benefit by formulating aqueous dispersions that are easy to handle. The water-based formulation eliminates flammability while the submicrometer particle size ensures good flow and processing characteristics, turning a previously problematic property into an advantage
Data Source
AI summary
A fabric softener active composition, comprising at least 0 % by weight of a bis-(2-hydroxypropyl)-dimethylammonium 5 methylsulphate fatty acid ester having a molar ratio of fatty acid moieties to amine moieties of from 1.5 to 1.99, wherein the average chain length of the fatty acid moieties is from 16 to 18 carbon atoms and the iodine value of the fatty acid moieties,calculated for the free fatty acid, is from 0.5 to 50, and from 0.5 to 5 % by weight fatty acid provides high softening performance and good storage stability in aqueous dispersion and can be handled and processed in a liquid state without addition of a flammable solvent.