Absorbent Article Microparticle Stain Concealment

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Solution Overview

Problem

Existing absorbent articles struggle to maintain the visibility of colored regions due to color contamination from body fluids, as the color difference between colored and surrounding regions becomes less distinct after absorption, making it difficult to discern the original pattern.

Innovation Solution

Incorporating non-absorbent, water-insoluble microparticles with a different color than the colored regions onto the liquid-permeable base sheet, ensuring their average particle size is smaller than the fiber material width, allowing them to adhere without blocking fluid permeability and concealing the color produced by body fluid stains, thus enhancing the visibility of the colored regions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If a colored layer is placed in contact with the back side of the liquid-permeable sheet to form colored regions, then the colored regions become visible through the top sheet, but the color of the colored regions and surrounding regions becomes the same, reducing visibility

Engineering Contradiction:
Improvevisibility of colored regionsVSAvoidcolor differentiation between regions
Core Design Contradiction:
Illumination intensityVSEase of manufacture

Solution Approach 1:

The invention applies different properties to different regions: the colored layer is applied selectively to specific regions (colored regions) while leaving surrounding regions without the colored layer or with different properties. This creates local differentiation in optical properties, allowing colored regions to be distinguished from surrounding regions when viewed through the top sheet.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The invention utilizes color changes by applying a colored layer that changes the optical appearance of specific regions. The colored layer contains pigments or dyes that absorb or reflect certain wavelengths of light, creating a visible color difference between colored regions and surrounding regions when viewed through the liquid-permeable top sheet.

Inventive Principle:
Principle #32Color changes

2Loss of information

If the colored layer is used to indicate channels, then the channels become visible, but body fluid absorption stains the surrounding regions with the same color, reducing the contrast and visibility

Engineering Contradiction:
Improvevisibility of channel patternVSAvoidcolor contamination from body fluid
Core Design Contradiction:
Loss of informationVSObject-affected harmful factors

Solution Approach 1:

The invention applies preliminary anti-action by pre-treating the surrounding regions with a stain-resistant coating or applying a barrier layer that prevents body fluid from staining these areas. This preliminary protective measure counteracts the harmful staining effect before it can occur, maintaining the original color contrast between colored regions and surrounding regions even after body fluid absorption.

Inventive Principle:
Principle #9Preliminary anti-action

Solution Approach 2:

The invention converts the harmful staining effect into a benefit by using the body fluid absorption as an indicator mechanism. The colored regions are designed to change color or become more visible when they absorb body fluid, while surrounding regions maintain their original appearance. This transforms the potential harm of staining into a useful function for indicating fluid absorption status and channel effectiveness.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

3Illumination intensity

If microparticles are attached to the base sheet to conceal stain color, then the visibility of colored regions is improved, but the particle size must be smaller than fiber width to maintain fluid permeability

Engineering Contradiction:
Improvevisibility of colored regions after absorptionVSAvoidfluid permeability of base sheet
Core Design Contradiction:
Illumination intensityVSQuantity of substance

Solution Approach 1:

The invention utilizes porous materials by attaching microparticles to the base sheet in a manner that maintains the porous structure. The microparticles are distributed on the surface or within the pores of the base sheet, filling some pore spaces but leaving sufficient open porosity for fluid permeability. This allows the microparticles to conceal stain colors while the base sheet retains its ability to absorb and transmit body fluid.

Inventive Principle:
Principle #31Porous materials

Solution Approach 2:

The invention creates a composite material structure by combining the base sheet with attached microparticles. The composite consists of the porous base sheet matrix and the dispersed microparticles, where the microparticles provide stain concealment functionality while the base sheet maintains fluid permeability. The synergistic combination of these two components achieves both visibility improvement and fluid absorption capabilities.

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 solution effectively conceals the color produced by body fluid absorption, maintaining the visibility and contrast of the colored regions, even after fluid absorption, without inhibiting the absorbent's fluid absorption properties.

Implementation Method 1

the microparticles adhere to the fiber material surface of the base sheet but do not block the back side or the gaps between the fiber material

Methodology Applied
Scientific EffectAdhesion: Adhesive

Data Source

PatentEP3459514B1Absorbent article
Publication Date: 2019.12.04 UNI CHARM CORP
  • EP3459514B1 patent drawingFigure 1
  • EP3459514B1 patent drawingFigure 2~3
  • EP3459514B1 patent drawingFigure 4(A)~4(B)

AI summary

Provided is an absorbent article configured such that a liquid-permeable sheet between a top sheet and an absorbent core has a colored region, and color due to absorbed bodily fluids in the colored region and the surrounding region is concealed, thereby improving the visibility of the colored region. An absorbent article wherein: there is a colored region (21) between a top sheet (13) and an absorbent core (11), said colored region (21) having a color that differs from that of the top sheet and being visible through the top sheet (13); there is a liquid-permeable substrate sheet between the top sheet (13) and the absorbent core (11), said substrate sheet including a fiber material; and there is a microparticle adhesion region (23) where non-absorbent and water-insoluble microparticles of a color different from the color of the colored region (21) have been adhered to the fiber material of the substrate sheet, with the average particle size of the microparticles being less than the average width of the fiber material of the substrate sheet. When the absorbent article is viewed in the thickness direction, the microparticle adhesion region (23) includes a region overlapping with both the colored region (21) and a surrounding region (22) that surrounds the colored region.