Absorbent Core Channels With Fast-Swelling SAP for Multi-Gush Uptake

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Solution Overview

Problem

Absorbent cores with channels experience a significant reduction in liquid absorption speed beyond the first gush due to the formation of three-dimensional channels that create resistance to swelling for superabsorbent polymers, leading to reduced absorption efficiency.

Innovation Solution

Incorporation of superabsorbent polymer particles with a time to reach an uptake of 20 g/g (T20) of less than 240 seconds, combined with areas in the core wrap free of absorbent material, allowing the core wrap to form channels that facilitate fluid distribution and maintain absorption speed.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If channels are formed in the absorbent core to facilitate fluid distribution, then fluid acquisition speed is improved, but absorption speed beyond the first gush is significantly reduced due to resistance to swelling

Engineering Contradiction:

Improvefluid acquisition speedVSAvoidabsorption speed beyond first gush

Core Design Contradiction:

SpeedVSProductivity

Solution Approach 1:

The patent changes the key parameter of superabsorbent polymer particles from conventional types to those with T20 less than 240 seconds. This parameter change allows the SAP to overcome the swelling resistance created by channels and maintain high absorption speed throughout multiple gushes, resolving the contradiction between initial fluid acquisition and sustained absorption performance.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates areas substantially free of absorbent material within the core, forming localized channels that facilitate fluid distribution. These channels are strategically positioned to improve fluid acquisition while the surrounding high-capacity SAP regions maintain absorption performance, balancing fluid distribution needs with sustained absorption capability.

Inventive Principle:

Principle #3Local quality

2Quantity of substance

If conventional superabsorbent polymers are used in cores with channels, then first gush absorption is maintained, but subsequent gush absorption is significantly reduced

Engineering Contradiction:

Improvefirst gush absorption capacityVSAvoidabsorption duration across multiple gushes

Core Design Contradiction:

Quantity of substanceVSDuration of action of moving object

Solution Approach 1:

The patent specifies superabsorbent polymer particles with T20 less than 240 seconds, fundamentally changing the absorption kinetics parameter. This enables the SAP to maintain high absorption speed across multiple gushes (extending duration of action) while preserving first gush absorption capacity, overcoming the limitation of conventional SAP in channeled cores.

Inventive Principle:

Principle #35Parameter changes

3Speed

If areas free of absorbent material are created to form channels, then fluid distribution is improved, but absorbent material is removed from potential absorption zones

Engineering Contradiction:

Improveliquid distribution speedVSAvoidtotal absorbent material capacity

Core Design Contradiction:

SpeedVSQuantity of substance

Solution Approach 1:

The patent introduces areas substantially free of absorbent material (channels) into the core structure. These localized non-absorbent regions facilitate rapid fluid distribution throughout the core, while the surrounding areas maintain high absorbent material concentration for capacity retention, achieving both fast distribution and sustained absorption.

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

Enhances fluid acquisition speed and better utilization of absorbent capacity by maintaining absorption efficiency throughout multiple gushes, preventing fluid leakage and ensuring rapid liquid distribution across the core.

Implementation Method 1

the absorbent material swells, so that the core wrap forms a channel along each area substantially free of absorbent material

Methodology Applied

Scientific EffectAbsorption: Absorption (physical)

Implementation Method 2

as the absorbent structure absorbs liquid and swells, the absorbent structure takes a three-dimensional shape with the channels becoming visible

Methodology Applied

Scientific EffectSwelling: Gel

Data Source

PatentUS12558274B2Absorbent cores having material free areas

Publication Date: 2026.02.24 PROCTER & GAMBLE CO

AI summary

An absorbent core, for use in an absorbent article, including a core wrap enclosing an absorbent material and including superabsorbent polymer particles. The core wrap includes a top side and a bottom side, and the absorbent core includes one or more area(s) substantially free of absorbent material through which the top side of the core wrap is attached to the bottom side of the core wrap, so that when the absorbent material swells the core wrap forms one or more channel(s) along the area(s) substantially free of absorbent material. The superabsorbent polymer particles have a time to reach an uptake of 20 g/g (T20) of less than 240 s as measured according to the K(t) test method.