Liquid-Activated Wetness Indicator Formulation
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Solution Overview
Problem
Current pH-based wetness indicators in absorbent articles are unreliable due to issues like premature triggering and leaching, and they have limited color options, necessitating the development of more reliable and versatile wetness/fluid indicators.
Innovation Solution
A single-layer liquid-activated formulation comprising a liquid-activated colorant, a hydrochromic ionic compound, an opacifier, a binding matrix, and a surfactant is introduced, which includes binding agents like rosin esters and quaternary ammonium compounds to immobilize the colorant and prevent leaching, while the surfactant enhances wettability and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pH-based colorants are used in wetness indicators, then color change indication is achieved, but premature triggering and leaching occur reducing reliability
Solution Approach 1:
A water-soluble binder is introduced as an intermediary substance that immobilizes the pH-based colorant within the wetness indicator composition. The binder acts as a carrier that prevents direct contact between the colorant and liquid while still allowing pH-mediated color change when urine is present, thus eliminating premature triggering and leaching issues.
Solution Approach 2:
The wetness indicator composition is formulated as a composite material combining pH-based colorants, water-soluble binders, and other functional components. This composite structure integrates the color-changing property of the colorant with the immobilizing function of the binder, creating a stable system that maintains colorant integrity while enabling reliable fluid detection.
2Adaptability or versatility
If pH indicators are used for wetness detection, then fluid presence is indicated through color change, but color options are limited
Solution Approach 1:
The water-soluble binder serves multiple functions simultaneously: it acts as a carrier for the pH indicator, provides immobilization to prevent leaching, maintains colorant stability during storage, and enables reliable color change response. This multi-functional approach allows a single formulation system to support various color options while maintaining high reliability.
3Ease of manufacture
If colorants are incorporated into absorbent articles, then wetness indication is provided, but leaching occurs compromising performance
Solution Approach 1:
The water-soluble binder functions as an intermediary that physically incorporates and immobilizes the colorant within the absorbent article formulation. This prevents colorant leaching during manufacturing and usage while maintaining the colorant's ability to change color in response to urine, thus eliminating the loss of substance problem.
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 provides reliable and varied color options by preventing premature color change and leaching, ensuring effective indication of fluid presence without compromising the absorbent article's performance.
Implementation Method 1
a surfactant. The formulation provides reliable and varied color options by preventing premature color change and leaching, ensuring effective indication of fluid presence without compromising the absorbent article's performance.
Implementation Method 2
a hydrochromic ionic compound
Implementation Method 3
The color changing active used in many wetness indicator compositions are pH indicators such as bromocresol green or the like, which changes color from yellow to blue in the pH range of 3.8 to 5.4.
Implementation Method 4
binding agents like rosin esters and quaternary ammonium compounds to immobilize the colorant and prevent leaching
Data Source
AI summary
A liquid-activated formulation is provided, comprising a liquid-activated colorant, a hydrochromic ionic compound, an opacifier, a binding matrix, and a surfactant.