Wet Indicator Composition for Fast Discoloration and Low Odor

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Solution Overview

Problem

Conventional wet indicators have inadequate moisture permeability, delayed discoloration, and unpleasant odors, which affect their performance and user experience.

Innovation Solution

A composition for wet indicators comprising hydrocarbon oil, saturated fatty acids with 16 or more carbon atoms, and a wet-sensitive colorant composition, including leuco dyes and anionic surfactants, which enhances moisture permeability, rapid discoloration, and reduces odor.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If a thermoplastic resin is used as the matrix in conventional wet indicator compositions, then the structural integrity is maintained, but the moisture permeability is insufficient and discoloration is delayed

Engineering Contradiction:
Improvediscoloration speedVSAvoidmoisture permeability
Core Design Contradiction:
SpeedVSReliability

Solution Approach 1:

The patent changes the chemical composition parameters of the matrix by replacing thermoplastic resin with specific hydrocarbon oils (paraffin oil, naphthene oil, or aromatic hydrocarbon oil) in controlled amounts (5-90 parts by mass). This parameter change transforms the matrix from a polymer-based system to a hydrocarbon oil-based system, which inherently provides better moisture permeability and faster discoloration response while maintaining structural integrity through the combination with saturated fatty acids and colorant composition.

Inventive Principle:
Principle #35Parameter changes

2Object-affected harmful factors

If conventional thermoplastic resin compositions are used, then the material stability is ensured, but unpleasant odors are generated and transferred to absorbent articles

Engineering Contradiction:
ImproveodorVSAvoidmaterial stability
Core Design Contradiction:
Object-affected harmful factorsVSStability of the object's composition

Solution Approach 1:

The patent creates a composite material system combining hydrocarbon oils (A) with saturated fatty acids (B) and wet-sensitive colorant composition (C). This composite approach allows the hydrocarbon oil to provide low odor characteristics while the saturated fatty acids and colorant composition maintain material stability and functional performance. The synergistic combination resolves the contradiction between odor reduction and stability maintenance.

Inventive Principle:
Principle #40Composite materials

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 excellent discoloration performance with clear and rapid color change, while minimizing odor, thus accurately indicating a wet state and improving user comfort.

Implementation Method 1

The wet indicator composition changes color in response to pH change

Methodology Applied
Scientific EffectpH change:

Implementation Method 2

permeability of moisture is not sufficiently excellent

Methodology Applied
Scientific EffectPermeation: Permeation

Implementation Method 3

a leuco dye and a color-developing agent in a hot melt adhesive matrix

Methodology Applied
Scientific EffectChemical reaction: Chemical Bonding

Data Source

PatentUS12575977B2Composition for wet indicator
Publication Date: 2026.03.17 HENKEL KGAA

AI summary

To provide a composition for wet indicator which is excellent in discoloration performance and is suppressed in odor. What is disclosed is a composition for wet indicator comprising: a hydrocarbon oil (A), at least one selected from saturated fatty acids having 16 or more carbon atoms and derivatives thereof (B), and a wet-sensitive colorant composition (C), wherein the component (B) is contained in an amount of 2 to 85 parts by mass based on 100 parts by mass of the total amount of the components (A) to (C).