Absorbent Article Polymer Sheet Fluid Diffusion

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Solution Overview

Problem

Existing absorbent articles face challenges in efficiently absorbing body fluids and preventing fit issues due to the swelling of superabsorbent polymers, which leads to reduced absorption efficiency and potential worsening of fit.

Innovation Solution

The absorbent article incorporates a polymer sheet with a superabsorbent polymer between an upper and lower layer sheet, featuring a liquid diffusion sheet that promotes fluid diffusion in the plane direction and prevents immediate movement to the lower layer, allowing the superabsorbent polymer to absorb fluids over a wider area, thereby preventing fit issues from swelling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If a superabsorbent polymer assembly in powder form is included inside the polymer sheet, then the polymer sheet can absorb and keep a large amount of body fluid, but the body fluid does not easily enter inside the polymer assembly and flows near the surface, being absorbed only by the superabsorbent polymer near the surface

Engineering Contradiction:
Improveabsorption capacityVSAvoidfluid penetration efficiency
Core Design Contradiction:
Quantity of substanceVSEase of operation

Solution Approach 1:

The patent uses a porous expanded sheet as the polymer sheet structure, which provides porous portions that facilitate easy entry of body fluid into the superabsorbent polymer assembly. The porous structure allows fluid to penetrate through the sheet and reach the polymer powder efficiently, resolving the contradiction between high absorption capacity and fluid penetration efficiency.

Inventive Principle:
Principle #31Porous materials

2Quantity of substance

If the superabsorbent polymer absorbs body fluid, then the absorption efficiency increases, but the swelling of the polymer causes increasing in thickness and worsening of fit

Engineering Contradiction:
Improveabsorption efficiencyVSAvoidfit maintenance
Core Design Contradiction:
Quantity of substanceVSShape

Solution Approach 1:

The patent provides space portions within the polymer sheet structure that accommodate the swelling of superabsorbent polymer in specific localized regions. This allows the polymer to expand and absorb fluid without causing overall thickness increase that would worsen fit, as the swelling is contained within predetermined spaces designed for this purpose.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The polymer sheet is divided into multiple regions including porous portions and space portions, where space portions are strategically placed to accommodate polymer swelling. This segmentation allows different parts of the sheet to serve different functions: porous portions for fluid entry and space portions for volume accommodation during absorption, thereby maintaining fit while achieving high absorption efficiency.

Inventive Principle:
Principle #1Segmentation

3Speed

If the body fluid is absorbed only by the superabsorbent polymer near the surface, then the absorption process is faster, but the overall absorption capacity is reduced due to fluid flowing near the surface without entering the polymer assembly

Engineering Contradiction:
Improveabsorption speedVSAvoidtotal absorption capacity
Core Design Contradiction:
SpeedVSQuantity of substance

Solution Approach 1:

The porous expanded sheet structure with porous portions provides multiple pathways for body fluid to penetrate into the polymer assembly. This increases the effective surface area for fluid entry and allows fluid to reach deeper regions of the superabsorbent polymer, thereby increasing total absorption capacity while maintaining absorption speed through the porous network.

Inventive Principle:
Principle #31Porous 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

This design enhances fluid absorption efficiency and prevents fit deterioration by allowing the superabsorbent polymer to absorb fluids evenly, reducing the risk of gel blocking and distortion from swelling.

Implementation Method 1

the body fluid does not easily enter inside the polymer assembly

Methodology Applied
Scientific EffectCapillary action: Capillary Action

Implementation Method 2

a superabsorbent polymer is provided between an upper layer sheet and a lower layer sheet

Methodology Applied
Scientific EffectAbsorption: Absorption (physical)

Implementation Method 3

featuring a liquid diffusion sheet that promotes fluid diffusion in the plane direction

Methodology Applied
Scientific EffectDiffusion: Diffusion

Data Source

PatentEP3388039B1Absorbent article
Publication Date: 2021.08.18 DAIO PAPER CORP
  • EP3388039B1 patent drawingFigure 1
  • EP3388039B1 patent drawingFigure 2
  • EP3388039B1 patent drawingFigure 3

AI summary

A polymer provided region (13) at which a superabsorbent polymer (12) is provided, and a polymer non-provided region (14) at which the superabsorbent polymer (12) is not provided are formed, a liquid diffusion sheet (15), that promotes diffusion of body fluid in a plane direction, is staked to be adjacent to a skin side surface of a lower layer sheet (11), and an upper layer sheet (10) is bonded with the liquid diffusion sheet (15) under a state that the upper layer sheet (10) contacts the liquid diffusion sheet (15), at the polymer non-provided region (14) to form a polymer sheet (4).