Sunscreen Stain Reduction via Complexing Agents
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Solution Overview
Problem
Existing sunscreens containing non-water-soluble UV-A filters like 2-[-4-(Diethylamino)-2-hydroxybenzoyl] benzoic acid hexyl ester cause stubborn stains on light-colored textiles and are difficult to wash out, leading to discoloration and premature aging of fabrics.
Innovation Solution
A cosmetic preparation with 2-[-4-(Diethylamino)-2-hydroxybenzoyl] benzoic acid hexyl ester, in combination with specific emulsifiers and complexing agents such as sodium and potassium salts, is formulated to enhance washability and reduce staining, particularly in the form of an oil-in-water emulsion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If non-water-soluble UV-A filters like 2-[-4-(Diethylamino)-2-hydroxybenzoyl] benzoic acid hexyl ester are used in sunscreen formulations, then UV protection effectiveness is improved, but staining of textiles and difficulty of washing out increases
Solution Approach 1:
The patent introduces water-soluble polymers containing carboxyl groups as intermediary substances that complex with non-water-soluble UV-A filters. These polymers act as mediators between the hydrophobic UV filters and the aqueous environment, forming water-soluble complexes that prevent direct contact with textile fibers while maintaining UV protection. The polymer chains with carboxyl groups bind to the UV filter molecules, creating soluble complexes that can be easily rinsed away from textiles.
Solution Approach 2:
The patent changes the solubility parameter of UV-A filters by forming complexes with water-soluble polymers. The UV filters themselves remain hydrophobic, but when complexed with the polymers, the overall complex becomes water-soluble. This parameter change allows the filters to be applied effectively and then easily removed from textiles during washing, resolving the staining issue while maintaining protection efficacy.
2Reliability
If non-water-soluble UV-A filters are used, then light protection filter performance is improved, but washability of contaminated textiles deteriorates
Solution Approach 1:
Water-soluble polymers serve as intermediaries that facilitate the removal of UV filters during washing. The polymers bind to the hydrophobic UV filters through their carboxyl groups, creating water-soluble complexes that can be easily washed away from textiles with conventional detergents and water, dramatically improving washability.
Solution Approach 2:
The patent applies water-soluble polymers during the sunscreen formulation stage, before any textile contamination occurs. This preliminary action ensures that the UV filters are pre-complexed with the polymers in a water-soluble form, preventing direct deposition on textiles in the first place and making subsequent washing easier.
3Ease of manufacture
If conventional detergents are used to wash stained textiles, then general cleaning is achieved, but stain removal is limited and stains worsen due to interactions with ions in washing water
Solution Approach 1:
The water-soluble polymers with carboxyl groups act as intermediaries that bind to UV filter molecules, preventing direct interaction between the stains and washing water ions. This intermediary layer prevents the worsening of stains during washing while allowing conventional detergents to effectively remove the polymer-UV filter complexes.
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 formulation significantly reduces staining on textiles during washing, as demonstrated by in vitro studies showing a substantial decrease in yellow spot formation and improved washability compared to formulations without complexing agents.
Implementation Method 1
A cosmetic preparation with 2-[-4-(Diethylamino)-2-hydroxybenzoyl] benzoic acid hexyl ester, in combination with specific emulsifiers and complexing agents such as sodium and potassium salts
Implementation Method 2
particularly in the form of an oil-in-water emulsion
Data Source
AI summary
The invention relates to a cosmetic preparation containing a) (2-[-4-(diethylamino)-2-hydroxybenzoyl] benzoic acid hexylester (INCI: diethylamino hydroxybenzoyl hexyl benzoate), and b) one or more complexing agents selected from the group comprising phosphonic acids, phosphoric acids and carboxylic acids with less than 2 nitrogen atoms and/or the alkali salts and/or the amine N-oxides thereof.