Sanitary Article pH Control Coating
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Solution Overview
Problem
Sanitary articles, such as sanitary napkins and diapers, often cause skin irritation due to pH increase and enzyme activity, which existing acidifying agents fail to effectively control without compromising absorbency or complicating the production process.
Innovation Solution
A sanitary article with a topsheet coated with a dry composition of organic acids (pKa ≤ 5.5) and a surface active agent, applied in a method that ensures prolonged skin protection, combined with a non-absorbent fibrous acquisition layer to maintain natural skin pH and improve adherence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If acidifying agents are applied in lotions to control pH, then skin pH control is improved, but absorbency is impaired and production process becomes complicated
Solution Approach 1:
The patent changes the physical state of the acidifying agent from liquid lotion form to dry powder form. This parameter change eliminates the need for complex lotion application processes while maintaining pH control efficacy. The dry coating can be simply applied to the topsheet and provides the same acidifying effect without impairing absorbency.
Solution Approach 2:
The patent extracts the active acidifying components (organic acids like lactic acid, citric acid, or malic acid) from the complex lotion formulation and uses them in a simplified dry powder form. This extraction eliminates unnecessary lotion components and simplifies the application process while retaining the essential pH control function.
2Object-affected harmful factors
If acidifying agents are applied in aqueous solutions to control pH, then skin pH control is improved, but absorbency is impaired
Solution Approach 1:
The patent changes the physical state of the acidifying agent from aqueous solution to dry powder form. This parameter change prevents the aqueous solution from interfering with the absorbent core's ability to absorb menstrual fluid, while still providing effective pH control through the dry coating on the topsheet.
3Object-affected harmful factors
If conventional acidifying agents are used to control pH, then skin pH control is achieved, but the effect is not prolonged
Solution Approach 1:
The patent uses composite materials consisting of organic acids (lactic acid, citric acid, or malic acid) combined with carriers such as clays, starches, or cellulose derivatives. This composite structure provides controlled release of the acidifying agents, extending the duration of pH control effect throughout the wear period of the sanitary article.
Solution Approach 2:
The patent employs porous carrier materials like clays or starches that can absorb and slowly release the organic acids. This porous structure enables sustained release of the acidifying agents over time, providing prolonged skin protection against alkaline pH increase during article use.
4Object-affected harmful factors
If acidifying agents are applied to control pH, then skin pH is reduced, but enzyme activity is not sufficiently inhibited
Solution Approach 1:
The patent specifically selects organic acids with pKa values between 3.5 and 5.5 (lactic acid, citric acid, malic acid) to achieve optimal pH reduction. This parameter selection ensures the pH is lowered sufficiently to inhibit pH-dependent enzyme activity while maintaining skin compatibility. The controlled pH range effectively reduces enzyme activity without causing excessive skin irritation.
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 effectively maintains natural skin pH, reducing skin irritation and enzyme activity while minimizing absorbency loss and simplifying the application process, providing a prolonged skin beneficial effect.
Implementation Method 1
an organic acid, having a pKa value not exceeding 5.5, and/or a salt thereof
Implementation Method 2
a surface active agent. The surface active agent ensures an adequate spreading and impregnation of the coating in the topsheet material
Implementation Method 3
a dry coating comprising a) an organic acid, having a pKa value not exceeding 5.5, and/or a salt thereof and b) a surface active agent
Data Source
AI summary
A sanitary article such as a sanitary napkin, a panty liner, a diaper, an incontinence pad, comprising a liquid permeable topsheet, a backsheet and a fibrous layer enclosed between said topsheet and backsheet wherein said fibrous layer consists essentially of non-absorbent fibers and said topsheet comprises a dry coating comprising a) an organic acid, having a pKa value not exceeding 5.5, and/or a salt thereof and b) a surface active agent.