Alpha-Sulfofatty Acid Ester Solubility in Cold Water
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Solution Overview
Problem
α-Sulfofatty acid esters used in detergents face issues such as degradation to di-salts, limited solubility in cold water and hard water, and pH drift, leading to reduced cleaning performance and stability concerns.
Innovation Solution
A liquid composition comprising α-sulfofatty acid esters and C8 alkyl dimethyl amine oxide, which maintains solubility and stability at cold temperatures and in hard water conditions, with a preferred eutectic mixture of C16 and C18 methyl ester sulfonates and C8 amine oxide hydrotrope, enhancing detergency and solubility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If α-sulfofatty acid esters are used in detergents, then cleaning performance is improved, but solubility in cold water and hard water deteriorates
Solution Approach 1:
The patent introduces a hydrotrope as an intermediary substance that mediates between the α-sulfofatty acid ester and water. The hydrotrope forms complexes with the surfactant, enhancing its solubility in cold water and hard water while preserving cleaning performance. This intermediary approach allows the surfactant to maintain effectiveness across diverse water conditions without requiring formulation changes.
Solution Approach 2:
The patent modifies the physical and chemical parameters of the detergent formulation by adjusting the concentration ratios of α-sulfofatty acid ester, hydrotrope, and nonionic surfactant. By optimizing these parameters, the formulation achieves enhanced solubility in cold water and hard water while maintaining high cleaning effectiveness. The specific parameter optimization includes controlling the ratio of anionic to nonionic surfactants and adjusting the hydrotrope concentration.
2Reliability
If α-sulfofatty acid esters are used in detergents, then cleaning performance is improved, but stability during storage and use deteriorates
Solution Approach 1:
The nonionic surfactant acts as a stabilizing intermediary that prevents degradation of the α-sulfofatty acid ester during storage and use. It forms protective complexes with the anionic surfactant, preventing hydrolysis and other degradation reactions. This intermediary mechanism ensures long-term stability while maintaining cleaning performance.
Solution Approach 2:
The patent stabilizes the formulation by optimizing the pH level and ionic strength parameters. By controlling these parameters, the formulation prevents pH drift and hydrolysis of the α-sulfofatty acid ester. The specific parameter control includes maintaining pH within a narrow range and adjusting salt concentrations to prevent premature precipitation or degradation.
3Reliability
If higher concentrations of surfactants are used, then cleaning performance is improved, but solubility at cold temperatures deteriorates
Solution Approach 1:
The hydrotrope serves as a solubilizing intermediary that enables high surfactant concentrations to remain soluble at cold temperatures. It forms soluble complexes with the surfactant molecules, preventing precipitation even at elevated concentrations and low temperatures. This intermediary mechanism allows the formulation to achieve high cleaning effectiveness without sacrificing solubility.
Solution Approach 2:
The patent creates a composite surfactant system combining α-sulfofatty acid ester, nonionic surfactant, and hydrotrope in specific ratios. This composite formulation leverages the complementary properties of each component: the high detergency of the anionic surfactant, the solubilizing capability of the nonionic surfactant, and the temperature stability provided by the hydrotrope. The composite structure enables high concentration solubility at cold temperatures.
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 composition provides excellent solubility and cleaning performance in cold water, reduces residue, and maintains stability, ensuring effective detergency and whiteness maintenance in laundry and other household cleaning applications.
Implementation Method 1
at least one alkyl dimethyl amine oxide in an amount effective to maintain the solubility of the α-sulfofatty acid ester in cold water
Implementation Method 2
The cleaning performance of anionic surfactants can be limited, however, by water hardness. Calcium and/or magnesium ions in hard water interfere with some anionic surfactants, such as alkyl olefin sulfonates, alkyl sulfates, linear alkyl sulfonates, and linear alkyl benzene sulfonates.
Data Source
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AI summary
The present invention provides liquid cleaning compositions useful in cold water and hard water laundry applications, and methods for making and using such compositions. The compositions of the invention use surfactants or surfactant blends, such as a-sulfofatty acid esters or mixtures thereof (optionally along with one or more additional components), that have increased solubility/stability at cold temperatures, at higher-than-usual concentrations, and/or in hard water, with the composition remaining as a clear liquid. In certain embodiments, the compositions of the invention may be provided in the form of a unit dose, for example in a water- soluble pack or pouch. In use, the compositions of the invention result in an enhanced detergency along with a reduced amount of residue remaining in the machine, on laundered garments or cleaned dishware or hard surfaces, and on the body in personal care settings, and demonstrate a longer shelf-life, particularly when stored or used in colder temperatures.