Acidic Textile Stain Removal Using Surfactant Chelation
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Solution Overview
Problem
Conventional methods fail to effectively remove yellow or orange stains caused by avobenzone and oxybenzone from textiles, especially when these stains are set in an alkaline wash, and often require the use of phosphoric acid, which is environmentally unsustainable and can damage textiles.
Innovation Solution
A method involving a use solution with a pH of less than 7, composed of surfactants, chelating agents, and acid, applied to textiles to break down and remove stains, which can be formulated as a solid composition for ease of use and environmental sustainability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If phosphoric acid is used to remove avobenzone stains, then stain removal effectiveness is improved, but environmental sustainability deteriorates and textile damage risk increases
Solution Approach 1:
The invention changes the pH parameter from highly acidic (phosphoric acid, pH < 2) to mildly acidic (citric acid, pH 3-6), maintaining stain removal effectiveness while reducing textile damage and environmental harm. This parameter modification allows the same functional outcome without the harmful side effects.
Solution Approach 2:
The invention replaces phosphoric acid with citric acid, which is biodegradable and environmentally benign. Citric acid occurs naturally and decomposes into harmless substances, making it a sustainable alternative that eliminates the environmental persistence problem associated with phosphoric acid.
2Reliability
If very low pH is used to remove stains, then stain removal effectiveness is improved, but textile damage risk increases
Solution Approach 1:
The invention modifies the pH parameter from very low (pH < 2 with phosphoric acid) to mildly acidic (pH 3-6 with citric acid). This parameter change maintains the acid's ability to break down avobenzone stains while reducing the corrosive effect on textile fibers, thereby preserving textile strength and integrity.
3Productivity
If alkaline wash solution is used, then general cleaning effectiveness is improved, but stain setting occurs
Solution Approach 1:
The invention applies acid treatment before the alkaline wash cycle to prevent stain setting. By lowering the pH first, the avobenzone remains in a removable state, and then the subsequent alkaline wash can clean the textile without setting the stain. This preliminary action sequence resolves the contradiction between cleaning effectiveness and stain prevention.
Solution Approach 2:
Instead of using alkaline solution first (conventional approach) and then trying to remove stains, the invention inverts the sequence by applying acid treatment first to prevent stain setting, followed by the alkaline wash. This reversed sequence eliminates the problem of stain setting while maintaining cleaning effectiveness.
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 method significantly reduces or eliminates yellow or orange stains from textiles, providing a sustainable and textile-safe solution for stain removal, effective across various surfaces and scales.
Implementation Method 1
preparing a use solution having a pH of less than 7 by mixing one or more surfactant, one or more chelating agent, and one or more acid with an aqueous solvent; applying the use solution to the textile
Implementation Method 2
the surfactants comprise a combination of anionic surfactants and nonionic surfactants
Implementation Method 3
one or more chelating agent
Data Source
AI summary
A composition having a pH of less than 7 and including one or more surfactants, one or more chelating agents, and one or more acid in an aqueous solvents is used to treat stains on a textile caused by sunscreen lotion. Sunscreen stains in textiles can be reduced to a Δb* of 5 or less as compared to the textile before staining. The method includes preparing a use solution having a pH of less than 7 by applying to the wash solution a solid composition comprising about 15 to about 60 wt-% of surfactants; about 4 to about 18 wt-% chelating agents; and about 10 to about 40 wt-% of an acid or a salt thereof, and washing the textile in the wash solution, where the method is capable or reducing the stain in the textile to a Δb* of 7 or less as compared to the textile before staining.