High-SAP Absorbent Core Structure for Wet Shape Stability

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Solution Overview

Problem

Conventional absorbent articles with high flexibility in the crotch region tend to lose shape and resiliency when wet, leading to increased risk of fluid leakage due to deformation under wearer movement.

Innovation Solution

An absorbent core structure comprising at least 80% superabsorbent polymers (SAP) enclosed in a core wrap with longitudinal channels and a core wrap bonded through adhesive, ensuring minimal deformation and leakage during use.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the absorbent core is made highly flexible to improve freedom of movement, then the wearer experiences improved comfort and mobility, but the core loses resiliency when wet and deforms under wearer movement, increasing the risk of fluid leakage

Engineering Contradiction:
Improvefreedom of movementVSAvoidresiliency when wet
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The absorbent core is divided into multiple segments or zones with different SAP concentrations and channel configurations. The crotch region contains channels and specific SAP distribution to maintain flexibility, while other regions have different properties to maintain overall structural resiliency when wet.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the absorbent core have different properties: the crotch region is designed with specific channel patterns and SAP distribution to provide flexibility and comfort, while other regions are optimized for fluid absorption and structural stability. This local differentiation allows the core to be flexible where needed while maintaining overall resiliency.

Inventive Principle:
Principle #3Local quality

2Quantity of substance

If the absorbent core uses a high content of superabsorbent polymers (at least 80% SAP) to improve fluid absorption capacity, then the core can absorb and retain larger quantities of exudates, but the core may deform and lose shape when compressed by wearer movement

Engineering Contradiction:
Improvefluid absorption capacityVSAvoidcore deformation
Core Design Contradiction:
Quantity of substanceVSShape

Solution Approach 1:

Channels are pre-formed in the absorbent material before the product is used. These channels maintain the core's structural integrity and prevent deformation by creating a framework that resists compression, while still allowing the high SAP content to absorb fluids effectively.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The core wrap is designed as a flexible yet structurally supportive enclosure that contains the high SAP content. The wrap maintains the core's shape during wearer movement while allowing the SAP to expand and absorb fluids, preventing deformation despite the high polymer content.

Inventive Principle:
Principle #30Flexible shells and thin films

3Reliability

If the core wrap is designed to enclose and immobilize the SAP to prevent leakage, then fluid retention improves, but the core may lose flexibility and comfort in the crotch region

Engineering Contradiction:
Improvefluid retentionVSAvoidcrotch region flexibility
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The core wrap is segmented or features localized regions with different bonding characteristics. In the crotch region, the wrap has reduced bonding or specific channel configurations that allow flexibility and movement, while other regions have stronger bonding to maintain overall fluid containment and prevent leakage.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different sections of the core wrap have different properties: the crotch region features specific bonding patterns, channel configurations, or material properties that provide flexibility and comfort, while other sections are designed for strong containment and leakage prevention. This local differentiation resolves the contradiction between flexibility and fluid retention.

Inventive Principle:
Principle #3Local quality

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 core maintains shape and resiliency while absorbing fluids, reducing the risk of leakage by immobilizing SAP within the core wrap, thus providing improved fluid retention and wearer comfort.

Implementation Method 1

The function of the absorbent core is to absorb and retain the exudates for a prolonged amount of time

Methodology Applied
Scientific EffectCapillary action: Capillary Action

Implementation Method 2

a blend of comminuted wood pulp with superabsorbent polymers (SAP) in particulate form, also called absorbent gelling materials (AGM)

Methodology Applied
Scientific EffectOsmosis: Osmosis

Implementation Method 3

the top side of the core wrap and the bottom side of the core wrap are bonded to each other through the channels

Methodology Applied
Scientific EffectAdhesion: Adhesive

Data Source

PatentEP2740450B1Absorbent core with high superabsorbent material content
Publication Date: 2025.12.31 PROCTER & GAMBLE CO
  • EP2740450B1 patent drawingFigure 1
  • EP2740450B1 patent drawingFigure 2
  • EP2740450B1 patent drawingFigure 3

AI summary

An absorbent core (28) and an absorbent article (20) such as diaper comprising the core. The absorbent core comprises a core wrap (16, 16') enclosing an absorbent material (60), wherein the absorbent material comprises at least 80% of superabsorbent polymers ("SAP") by weight of the absorbent material. The absorbent core has a Relative Wet Caliper Increase (RWCI) after compression of less than 10% as measured by the Wet Caliper And Compression Force (WCACF) Test as described herein, and wherein the core wrap (16, 16') is at least partially sealed so that substantially no absorbent material leaks out of the core wrap while performing the WCACF Test.