Non-tacky Wetness Indicator Composition for Polymeric Substrates

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Solution Overview

Problem

Existing color-developing indicators for polymeric substrates are tacky, making them unsuitable for absorbent articles and requiring a composition that is non-leachable, durable, and exhibits a clear color change when exposed to an aqueous solution.

Innovation Solution

A color-developing composition comprising a leuco dye, an electron-withdrawing color-developer agent, and a desensitizer, dissolved in a volatile organic solvent medium, which changes from a colorless to a vibrant color upon exposure to an aqueous solution, with optional binders for printing and adhesion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional color-developing indicators are applied to polymeric substrates, then color change functionality is achieved, but the composition remains tacky and unsuitable for absorbent articles

Engineering Contradiction:
Improvecolor change functionalityVSAvoidtackiness
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent changes the chemical composition parameters by introducing a desensitizer component that modifies the interaction between the color-developing composition and the polymeric substrate. This parameter change eliminates tackiness while preserving color change functionality, making the composition suitable for absorbent articles.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite material system combining leuco dye, color developer, and desensitizer components. This composite approach allows the desensitizer to counteract the tacky properties of the color-developing agents while maintaining the color change response to moisture, resolving the contradiction between functionality and harmful tackiness.

Inventive Principle:
Principle #40Composite materials

2Reliability

If color-developing composition is applied to polymeric substrates, then moisture detection is enabled, but the composition may be leachable and lack durability

Engineering Contradiction:
Improvemoisture detection capabilityVSAvoidleachability
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent modifies the chemical parameters of the composition by selecting specific desensitizer molecules that enhance binding affinity to the polymeric substrate. This parameter optimization reduces leachability while maintaining moisture detection capability, addressing the durability concern.

Inventive Principle:
Principle #35Parameter changes

3Ease of manufacture

If existing color indicators are used, then color change is achieved, but the composition does not exhibit low tack required for manufacturing

Engineering Contradiction:
Improvemanufacturing suitabilityVSAvoidtackiness
Core Design Contradiction:
Ease of manufactureVSObject-generated harmful factors

Solution Approach 1:

The patent changes the compositional parameters by incorporating desensitizer at optimized concentrations that eliminate tackiness. This parameter adjustment makes the composition suitable for conventional printing techniques and absorbent article manufacturing, directly improving ease of manufacture.

Inventive Principle:
Principle #35Parameter changes

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 composition exhibits low tack, is non-leachable, and provides a visually distinct color change upon wetting, suitable for use in absorbent articles and applied using conventional printing techniques.

Implementation Method 1

a complex formed from a leuco dye, a electron-withdrawing color-developer agent, and a separator, where said leuco dye and color-developer are capable of interacting to manifest color when said separator dissolves or disperses in the presence of an aqueous solution

Methodology Applied
Scientific EffectColor development through chemical interaction: Chemical Bonding

Implementation Method 2

a color-developing composition comprising a leuco dye, an electron-withdrawing color-developer agent, and a desensitizer, dissolved in a volatile organic solvent medium

Methodology Applied
Scientific EffectEvaporation: Evaporation

Data Source

PatentEP2782537B1Non-tacky wetness indicator composition for application on a polymeric substrate
Publication Date: 2018.11.07 KIMBERLY CLARK WORLDWIDE INC
  • EP2782537B1 patent drawingFigure 1A~1B
  • EP2782537B1 patent drawingFigure 2
  • EP2782537B1 patent drawingFigure 3

AI summary

The invention describes a color-developing composition that contains at least three major components: (1) a leuco dye or a combination of leuco dyes, (2) an color-developer or a combination of color-developers that can form colored complexes with the leuco dyes, and (3) a desensitizer to temporarily remove the effect of the developer so the leuco dye appears in its colorless form. An optional binder may be included so that the composition may be applied to a substrate as an ink. The ink composition may be applied to synthetic polymeric substrates and other substrates that are incorporated into absorbent articles or personal care products.