Absorbent Core Fluid Immobilization via Layer Segmentation

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Solution Overview

Problem

Existing absorbent cores for sanitary napkins and similar products face challenges in efficiently managing and retaining body fluids, particularly menses or blood, due to limitations in fluid distribution and immobilization, leading to discomfort and reduced effectiveness.

Innovation Solution

A three-layer composite absorbent core structure is introduced, comprising a substrate layer with synthetic fibers, a layer of absorbent polymer material, and a layer of adhesive, where the absorbent polymer material is sandwiched between the substrate layer and the adhesive, with a cover layer optional, to enhance fluid management and retention.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a thin absorbent core structure is used, then comfort and discreetness are improved, but fluid distribution and immobilization efficiency deteriorate

Engineering Contradiction:
ImprovecomfortVSAvoidfluid immobilization efficiency
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The absorbent core is divided into three distinct functional layers: a first fibrous nonwoven layer for fluid acquisition, a superabsorbent polymer layer for fluid absorption and immobilization, and a second fibrous nonwoven layer for fluid distribution. This segmentation allows each layer to perform its specific function efficiently within a thin overall structure, resolving the contradiction between thin design and fluid management effectiveness.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention uses a composite structure combining different materials with complementary properties: fibrous nonwoven materials for fluid wicking and distribution, and superabsorbent polymers for bulk fluid absorption. This composite approach enables the thin core to achieve both comfort and effective fluid immobilization by leveraging the strengths of each material type.

Inventive Principle:
Principle #40Composite materials

2Reliability

If superabsorbent materials are localized in concentrated arrangements, then fluid retention is improved, but fluid distribution capability deteriorates

Engineering Contradiction:
Improvefluid retentionVSAvoidfluid distribution capability
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The system separates fluid distribution and fluid retention functions into different layers. The first fibrous nonwoven layer handles fluid distribution through capillary action, while the superabsorbent polymer layer handles fluid retention. This functional segmentation resolves the contradiction by allowing each layer to optimize for its specific purpose without compromising the other.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The first fibrous nonwoven layer acts as an intermediary between fluid source and the superabsorbent polymer layer. It receives fluid from the topsheet and distributes it evenly across the superabsorbent layer, preventing localized saturation and ensuring uniform fluid retention throughout the concentrated superabsorbent regions.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 structure improves fluid immobilization and absorption efficiency, providing better comfort and performance during use by optimizing the distribution and retention of body fluids, even with complex fluids like menses or blood, while maintaining a thin and flexible design.

Implementation Method 1

a layer of absorbent polymer material... capable of absorbing large quantities of liquids and of retaining such absorbed liquids

Methodology Applied
Scientific EffectAbsorption: Absorption (physical)

Implementation Method 2

a layer of adhesive... The first layer is joined to a face of the second layer in a face to face relationship by bonding between the layers

Methodology Applied
Scientific EffectAdhesion: Adhesive

Implementation Method 3

The substrate layer comprises a composite of at least a first layer and third layer of fibrous nonwoven webs

Methodology Applied
Scientific EffectCapillary action: Capillary Action

Data Source

PatentEP2453859B1Absorbent core
Publication Date: 2016.06.01 PROCTER & GAMBLE CO
  • EP2453859B1 patent drawingFigure 1~2
  • EP2453859B1 patent drawingFigure 3~4
  • EP2453859B1 patent drawingFigure 5

AI summary

Absorbent core for disposable absorbent articles, for example for the absorption of menses or blood. The absorbent core comprises a substrate layer, thereon a layer of absorbent polymer material, and thereon a layer of adhesive. Either said a substrate layer or said cover layer or both may comprises o composite of at least a first layer and third layer of fibrous non-woven webs, said first layer and said third layer comprising synthetic fibers with an average fiber denier from 1 to 6, said composite further comprises a second layer comprising pulp; the layers of the composite being placed in the order first- second- third and bonded by intertwining the fibers between the layers, e.g. by hydroentanglement. Said first and third layers of said composite may be spunbonded.