Absorbent Body Core Wrapping Sheet Liquid Diffusion

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Solution Overview

Problem

Existing absorbent bodies in absorbent articles, such as disposable diapers, face challenges in efficiently diffusing and transferring liquids both in the plane and thickness directions due to insufficient liquid transfer capabilities of diffusion sheets, leading to reduced absorbability.

Innovation Solution

An absorbent body design featuring a core wrapping sheet with a first hydrophilic fiber containing layer, a pulp fiber containing layer, and a second hydrophilic fiber containing layer, where pulp fibers penetrate the first layer to contact the absorbent core, enhancing liquid diffusion and transfer in both directions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If a diffusion sheet is used to diffuse liquid in the plane direction, then liquid diffusion capability is improved, but liquid transfer capability in the thickness direction deteriorates

Engineering Contradiction:
Improveliquid diffusion speed in plane directionVSAvoidliquid transfer capability in thickness direction
Core Design Contradiction:
SpeedVSDifficulty of detecting and measuring

Solution Approach 1:

The diffusion sheet is segmented into multiple functional layers: a first hydrophilic fiber layer for rapid liquid uptake, a pulp fiber layer for capillary-driven diffusion in plane direction, and a second hydrophilic fiber layer for liquid transfer to the absorbent core. This segmentation allows each layer to specialize in specific liquid transfer functions, resolving the contradiction between plane diffusion and thickness transfer capabilities.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The diffusion sheet uses a composite structure combining different fiber types (hydrophilic fibers and pulp fibers) with distinct properties. The hydrophilic fibers provide rapid liquid absorption and transfer, while the pulp fibers enable capillary diffusion in the plane direction. This composite material approach allows simultaneous optimization of both plane diffusion and thickness transfer capabilities.

Inventive Principle:
Principle #40Composite materials

2Quantity of substance

If liquid is repeatedly absorbed, then absorbability is improved, but liquid transfer efficiency deteriorates due to saturation

Engineering Contradiction:
Improvetotal liquid absorption quantityVSAvoidliquid transfer efficiency
Core Design Contradiction:
Quantity of substanceVSProductivity

Solution Approach 1:

Different layers of the diffusion sheet have different local qualities optimized for specific functions. The hydrophilic fiber layers are designed with high liquid affinity for rapid uptake and transfer, while the pulp fiber layer provides capillary structures for sustained plane diffusion. This local quality differentiation ensures that liquid transfer efficiency is maintained even after repeated absorption events, as each layer continues to perform its specialized function.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The invention addresses repeated absorption by creating a three-dimensional multi-layer structure that provides multiple liquid transfer pathways. When one pathway becomes saturated, liquid can still be transferred through alternative pathways in different layers, maintaining overall transfer efficiency. The vertical arrangement of layers creates dimensional redundancy that prevents saturation from compromising productivity.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 body effectively diffuses and transfers liquids in both the plane and thickness directions, improving absorbability and handling repeated liquid absorption efficiently.

Implementation Method 1

a first hydrophilic fiber containing layer which is adjacent to the absorbent core and includes first hydrophilic fibers with an average fiber length of 25 mm to 75 mm

Methodology Applied
Scientific EffectCapillary action: Capillary Action

Implementation Method 2

a pulp fiber containing layer which is adjacent to the first hydrophilic fiber containing layer and includes pulp fibers, and a portion of the pulp fibers in the pulp fiber containing layer penetrates the first hydrophilic fiber containing layer and is in contact with the absorbent core

Methodology Applied
Scientific EffectCapillary action: Capillary Action

Implementation Method 3

a second hydrophilic fiber containing layer which is adjacent to the pulp fiber containing layer and includes second hydrophilic fibers with an average fiber length of 25 mm to 75 mm

Methodology Applied
Scientific EffectCapillary action: Capillary Action

Data Source

PatentEP3357466B1Absorbent body for absorbent article
Publication Date: 2019.05.08 UNI CHARM CORP
  • EP3357466B1 patent drawingFigure 1
  • EP3357466B1 patent drawingFigure 2
  • EP3357466B1 patent drawingFigure 3(a)~3(b)

AI summary

The purpose of the present disclosure is to provide an absorbent body which, when repeatedly absorbing a liquid, exhibits excellent capabilities to disperse the liquid in the direction of the surface and to allow the liquid to migrate in the direction of the thickness. This absorbent body is configured as follows. The absorbent body (7) for an absorbent article (1) comprises: an absorbent core (11) comprising a polymer absorbing agent (19); and core wraps (13, 14). The core wraps (13, 14) comprise: (i) a first hydrophilic fiber-containing layer (25, 26) that is adjacent to the absorbent core (11) and contains first hydrophilic fibers (23, 24) having an average fiber length of 25 mm to 75 mm; (ii) a pulp fiber-containing layer (29, 30) that is adjacent to the first hydrophilic fiber-containing layer (25, 26) and contains pulp fibers (27, 28); and (iii) a second hydrophilic fiber-containing layer (33, 34) that is adjacent to the pulp fiber-containing layer (29, 30) and contains second hydrophilic fibers (31, 32) having an average fiber length of 25 mm to 75 mm. Some of the pulp fibers (27, 28) pass through the first hydrophilic fiber-containing layer (25, 26) and are in contact with the absorbent core (11).