Wet wipes with a cellulosic substrate and gentle lotion
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Solution Overview
Problem
Wet wipes with high water content struggle to inhibit microbial growth effectively due to the lack of preservative system efficacy, often requiring chemical surfactants that are undesirable for baby skin care, and can interact with the substrate, reducing preservative effectiveness.
Innovation Solution
The use of a lotion with a preservative system comprising benzoic acid, succinic acid, and phytic acid, along with a pH buffering system, which maintains a pH of 3.5 to 5 and is free of surfactants and fatty acid-containing materials, ensuring effective microbial inhibition without substrate interaction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the water content of the lotion is increased to make it gentler on skin, then the lotion becomes more gentle and mild, but the ability to inhibit microbial growth deteriorates
Solution Approach 1:
The patent changes the chemical parameters of the preservative system by selecting specific acids (benzoic acid, succinic acid, phytic acid) and their salts that remain effective at low concentrations in high-water-content lotions. The pH is optimized to 3.5-5.0 to maximize preservative efficacy while maintaining skin compatibility. This parameter optimization allows the lotion to achieve both high water content (96-99.5%) for gentleness and effective microbial inhibition.
2Reliability
If chemical surfactants are used to disperse preservative components in high water content lotion, then the preservative system can be stabilized, but the skin harshness and odor increase
Solution Approach 1:
The patent extracts and eliminates chemical surfactants from the formulation entirely. Instead of using surfactants to disperse preservative components, the invention relies on the inherent solubility of the selected preservative acids and salts in water, combined with optimized pH control. This removal of surfactants eliminates the associated skin harshness and odor problems while maintaining preservative system stability through alternative mechanisms.
Solution Approach 2:
The patent introduces pH buffering systems as intermediary components that mediate between the preservative acids and the aqueous environment. The buffering system (using citric acid, sodium citrate, or other buffers) maintains the optimal pH range of 3.5-5.0, which ensures both the effectiveness and stability of the preservative system without requiring chemical surfactants. This intermediary buffering mechanism resolves the stability issue while avoiding surfactant-related harm.
3Productivity
If the lotion components are made more available to participate in reactions with the substrate, then the cleaning effectiveness may improve, but the preservative system effectiveness deteriorates
Solution Approach 1:
The patent applies local quality by selecting preservative components with specific chemical properties that create different interaction behaviors with the substrate. The chosen preservatives (benzoic acid, succinic acid, phytic acid and their salts) have varying degrees of substrate interaction - phytic acid and its salts notably have reduced interaction with cellulosic fibers compared to other preservatives. This selective component choice allows the system to maintain preservative effectiveness while still providing cleaning functionality through the high-water-content lotion formulation.
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 solution achieves a Bacterial Log Reduction Factor of greater than or equal to 3 and Yeast and Mold Log Reduction Factor of greater than or equal to 2 at day 28, maintaining preservative system efficacy and gentleness on baby skin.
Implementation Method 1
a preservative system comprising benzoic acid and/or a salt thereof, succinic acid and/or a salt thereof, and phytic acid and/or a salt thereof
Implementation Method 2
The lotion also comprises a pH buffering system and a preservative system comprising benzoic acid and/or a salt thereof, succinic acid and/or a salt thereof, and phytic acid and/or a salt thereof. The lotion has a pH of about 3.5 to about 5.
Data Source
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AI summary
A wet wipe with a substrate having cellulosic fibres and a lotion is provided. The lotion comprises between about 96.0% and about 99.5%, by weight of the lotion, of water, a pH buffering system and a preservative system comprising benzoic acid and/or a salt thereof, succinic acid and/or a salt thereof, and phytic acid and/or a salt thereof. The lotion has a pH of about 3.5 to about 5. The buffering system may comprise citric acid and sodium citrate. The lotion may be devoid of fatty acid-containing materials and/or surfactants.