Absorbent Layer Structure for Viscous and Non-Viscous Liquid Uptake

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Solution Overview

Problem

Existing absorbent articles fail to efficiently absorb viscous liquids such as urine or menstrual blood, especially when they absorb viscous liquids such as muddy feces or watery feces, leading to leaks and leaks.

Innovation Solution

A new absorbent article comprising a super absorbent nonwoven fabric with a surface exposed to viscous liquids, and first super absorbent polymer particles adjacent to the back surface of the super absorbent nonwoven fabric, with a convex bulging upward in each cell to improve absorption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If a cell absorbing sheet with super absorbent polymer particles is used, then absorption performance for non-viscous liquid is improved, but absorption speed for viscous liquid deteriorates

Engineering Contradiction:
Improveabsorption capacityVSAvoidabsorption speed
Core Design Contradiction:
Quantity of substanceVSSpeed

Solution Approach 1:

The absorber is divided into two functional layers: an upper auxiliary layer with high absorption speed for viscous liquids and a main absorption layer with high capacity for non-viscous liquids. This segmentation allows each layer to specialize in its optimal function, resolving the contradiction between speed and capacity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the absorber are given different properties: the upper auxiliary layer has high porosity and hydrophilicity for rapid viscous liquid uptake, while the main absorption layer has high super absorbent polymer content for bulk liquid storage. This local differentiation resolves the speed-capacity trade-off.

Inventive Principle:
Principle #3Local quality

2Ease of manufacture

If the absorber structure is simplified, then manufacturing cost is reduced, but absorption performance for viscous liquid deteriorates

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidabsorbability
Core Design Contradiction:
Ease of manufactureVSQuantity of substance

Solution Approach 1:

The upper auxiliary layer serves multiple functions: it acts as a distribution layer for viscous liquids, provides initial absorption capacity, and works synergistically with the main absorption layer. This multi-functionality reduces the need for separate specialized components, simplifying manufacturing while maintaining performance.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 absorbent article effectively absorbs both viscous and non-viscous liquids, preventing leaks and improving absorption speed.

Implementation Method 1

the super absorbent nonwoven fabric can quickly absorb and diffuse even the viscous liquid

Methodology Applied
Scientific EffectCapillary action: Capillary Action

Implementation Method 2

the absorbed and diffused viscous liquid is delivered to the first super absorbent polymer particles adjacent to the back surface of the super absorbent nonwoven fabric so as to be absorbed and retained

Methodology Applied
Scientific EffectOsmosis: Osmosis

Data Source

PatentEP4035638B1Absorbent article
Publication Date: 2025.12.10 DAIO PAPER CORP
  • EP4035638B1 patent drawingFigure 1
  • EP4035638B1 patent drawingFigure 2
  • EP4035638B1 patent drawingFigure 3

AI summary

To achieve both of absorbability of a viscous liquid and absorption performance of a non-viscous liquid. The above problem is solved by a configuration in which an upper auxiliary layer 71 of an absorber 70 includes a super absorbent nonwoven fabric 42 having a surface exposed on an uppermost surface of the absorber 70 and having a Klemm water absorptiveness of 100 mm or more, first super absorbent polymer particles 43 adjacent to a back surface of the super absorbent nonwoven fabric 42, the main absorption layer 72 of the absorber 70 is a cell absorbing sheet 50 including second super absorbent polymer particles 53 contained in the cells 55 arranged at intervals, a convex 50p bulging upward is formed in a portion located at each cell 55 in an upper sheet 51, the first super absorbent polymer particles 43 are fixed to the upper surface of the upper sheet 51 of the main absorption layer 72, and an adhesion amount of the first super absorbent polymer particles 43 on the upper surface of the upper sheet 51 increases from the top of a convex 50p toward the bottom of a valley located between a convex 50p and a convex 50P adjacent each other.