Lactone Coated Absorbent Article pH Control
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Solution Overview
Problem
Conventional absorbent hygiene articles often cause skin irritation and infections due to pH imbalance, with acidifying agents like lactic acid losing effectiveness during storage, leading to reduced shelf life and impaired absorbency.
Innovation Solution
A disposable absorbent hygiene article with a dry coating comprising γ- and δ-lactones on the topsheet or intermediate layer, which maintains a skin-friendly pH range of 3.5 to 5.5 by adjusting the pH and extending the shelf life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If acidifying agents like lactic acid are incorporated into absorbent articles to control skin pH, then skin pH is adjusted to beneficial levels, but the pH effect decreases during storage leading to shortened shelf life
Solution Approach 1:
The patent changes the chemical form of the acidifying agent from pre-formed lactic acid to lactic acid precursors (lactones). This parameter change transforms the substance from an active acid that degrades over time to a stable precursor that maintains low pH through controlled hydrolysis, resolving the contradiction between pH control effectiveness and shelf life stability
Solution Approach 2:
The patent applies preliminary action by incorporating stable lactic acid precursors during manufacturing that will gradually convert to lactic acid during use. This ensures consistent pH control is established before the article is needed, while the stable precursor form maintains effectiveness throughout storage without degradation
2Reliability
If lactic acid is applied in aqueous solution to maintain skin pH, then pH control is achieved, but absorbency of the sanitary article is impaired
Solution Approach 1:
The patent changes the physical state and chemical form from aqueous lactic acid solution to dry lactone coating. This parameter change eliminates the free water that would interfere with absorbency while maintaining pH control functionality through the hydrolysis of lactones upon contact with skin moisture
Solution Approach 2:
The patent extracts the harmful element (excess water from aqueous solution) while retaining the beneficial function (pH control). The dry lactone coating removes the water component that impairs absorbency, allowing the acidifying function to be achieved through controlled hydrolysis rather than direct application of aqueous acid
3Reliability
If lotion is applied to the absorbent article for pH control, then skin pH is adjusted, but the production process becomes complicated
Solution Approach 1:
The patent merges the pH control function into the manufacturing process itself by incorporating lactone precursors during article production. This eliminates the separate post-manufacturing lotion application step, combining quality control into the production line and simplifying the overall process while maintaining effective pH control
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 lactone coating effectively maintains a low pH on the skin surface, reducing skin irritation and infections while prolonging the shelf life of the absorbent article by stabilizing the pH during storage.
Implementation Method 1
The pH adjusting effect of the lactone is based on the hydrolysis reaction in the presence of water
Data Source
AI summary
A disposable absorbent hygiene article is provided, comprising a liquid permeable topsheet, a backsheet and an absorbent core disposed between the topsheet and the backsheet. In the article, at least one layer, selected from said topsheet and an optionally present liquid permeable and nonabsorbent layer disposed between said topsheet and said absorbent core, is provided with a dry coating comprising at least one lactone selected from the group consisting of γ- and δ-lactones.