Composite Absorbent Structure with Heterogeneous SAP Distribution

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Solution Overview

Problem

Existing absorbent cores in personal hygiene products, such as diapers, face challenges in maintaining prolonged fluid absorption and minimizing re-wet, especially overnight, due to limitations in fluid distribution and capillary pressure, particularly in airfelt-free designs without sufficient loft and uniform distribution of superabsorbent particles.

Innovation Solution

A composite absorbent structure is formed by advancing a high loft nonwoven web with void spaces, distributing superabsorbent particles within these voids, and orienting them heterogeneously to enhance fluid absorption and distribution, using a process that includes a high loft layer with porosity above 90% and superabsorbent fibers up to 100% by weight, ensuring efficient fluid intake and permeability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If airfelt-free cores are used without sufficient loft, then manufacturing complexity is reduced, but fluid distribution and capillary pressure performance deteriorate

Engineering Contradiction:
Improvemanufacturing complexityVSAvoidfluid distribution performance
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent employs a high loft nonwoven substrate with controlled porosity (90-95%) to create void spaces that facilitate fluid distribution. The porous structure allows fluids to penetrate and distribute uniformly throughout the absorbent core while maintaining appropriate capillary pressure, resolving the contradiction between simplified manufacturing and performance reliability.

Inventive Principle:
Principle #31Porous materials

Solution Approach 2:

The invention creates a composite structure combining superabsorbent polymer particles (20-80 mesh size) with a high loft nonwoven substrate. This composite material integrates the absorption capacity of SAP particles with the fluid distribution capabilities of the lofted nonwoven matrix, achieving both manufacturing simplicity and superior fluid management performance.

Inventive Principle:
Principle #40Composite materials

2Quantity of substance

If superabsorbent particles are uniformly distributed, then absorption capacity is improved, but fluid distribution and capillary pressure performance deteriorates

Engineering Contradiction:
Improveabsorption capacityVSAvoidfluid distribution performance
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The patent implements a non-uniform distribution of superabsorbent particles within the high loft nonwoven substrate. Larger particles (20-80 mesh) are strategically positioned to create zones of varying absorption capacity, which optimizes both fluid distribution pathways and capillary pressure characteristics while maintaining overall absorption effectiveness.

Inventive Principle:
Principle #3Local quality

3Reliability

If high loft nonwoven web with porosity above 90% is used, then fluid permeability is improved, but structural stability deteriorates

Engineering Contradiction:
Improvefluid permeabilityVSAvoidstructural stability
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent optimizes the porosity parameter of the nonwoven substrate to a specific range (90-95%), balancing fluid permeability requirements with structural stability. The controlled porosity allows sufficient fluid flow while the nonwoven matrix maintains adequate mechanical integrity to support the absorbent particles and function as a stable absorbent core structure.

Inventive Principle:
Principle #35Parameter changes

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 solution significantly improves fluid absorption and distribution within absorbent articles, maintaining dryness and reducing re-wet, by utilizing high loft nonwoven webs with superabsorbent fibers and particles, enhancing the absorbent core's ability to handle fluid exudates effectively over time.

Implementation Method 1

drawing at least some of the superabsorbent particles into void spaces of the nonwoven web substrate to form the composite absorbent structure

Methodology Applied
Scientific EffectCapillary action: Capillary Action

Implementation Method 2

increased permeability and lower capillary pressure

Methodology Applied
Scientific EffectPermeability: Permeation

Implementation Method 3

lower capillary pressure

Methodology Applied
Scientific EffectCapillary pressure: Capillary Pressure

Implementation Method 4

absorb and retain the exudates for a prolonged amount of time

Methodology Applied
Scientific EffectAbsorption: Absorption (physical)

Data Source

PatentUS20220362072A1Process for forming composite absorbent material and composite absorbent material made by the process
Publication Date: 2022.11.17 PROCTER & GAMBLE CO

AI summary

A process for forming a composite absorbent structure by advancing a nonwoven web including from 20% to 100% by weight of superabsorbent fibers. Superabsorbent particles may be distributed to the nonwoven web and at least some of the superabsorbent particles may be drawn into void spaces of the nonwoven web to form the composite absorbent structure. The composite absorbent structure may include a nonwoven web comprising from 20% to 100% by weight of superabsorbent fibers, and the superabsorbent particles may be distributed heterogeneously into void spaces within the nonwoven web. The composite absorbent structure may be used in an absorbent article.