Soft Absorbent Sandwich Web with High SAM Concentration

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Solution Overview

Problem

Current absorbent structures with high concentrations of superabsorbent materials (SAM) face challenges in achieving both high absorbency and good tactile properties, while also requiring complex manufacturing processes and limited liquid distribution capabilities.

Innovation Solution

A liquid absorbent sandwich web composition featuring 70-90% SAM, 5-25% interspersed cellulosic fibers, and 1-5% self-crosslinking latex binder, with a manufacturing process involving compaction and thermal treatment to form a particle matrix and induce crosslinking, enhancing absorbency and mechanical strength while maintaining softness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If high concentrations of superabsorbent material (SAM) are used to increase absorbency, then the absorbency is improved, but the tactile properties and softness deteriorate

Engineering Contradiction:
ImproveabsorbencyVSAvoidtactile properties
Core Design Contradiction:
Quantity of substanceVSObject-affected harmful factors

Solution Approach 1:

The patent uses a composite structure combining cellulosic fibers (5-25%) with superabsorbent material (70-90%) to create a material that maintains softness while achieving high absorbency. The cellulosic fibers act as a soft matrix that distributes the SAM particles, preventing the harsh tactile sensation associated with high SAM concentrations alone.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent applies binder material selectively at specific locations and concentrations to immobilize SAM particles only where necessary, rather than uniformly throughout the entire structure. This localized binding approach maintains softness in non-critical areas while providing particle stability where needed.

Inventive Principle:
Principle #3Local quality

2Quantity of substance

If high concentrations of superabsorbent material (SAM) are used to increase absorbency, then the absorbency is improved, but the liquid distribution capability deteriorates

Engineering Contradiction:
ImproveabsorbencyVSAvoidliquid distribution capability
Core Design Contradiction:
Quantity of substanceVSProductivity

Solution Approach 1:

The patent creates regions with different SAM concentrations and fiber distributions to optimize both absorption and distribution. The cellulosic fibers provide channels for liquid distribution while the SAM particles provide absorption capacity, with each component performing its optimal function in specific local zones.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent divides the absorbent structure into functional zones where SAM particles are distributed among cellulosic fibers, creating a segmented architecture that facilitates liquid distribution pathways while maintaining high absorption capacity in specific regions.

Inventive Principle:
Principle #1Segmentation

3Quantity of substance

If high concentrations of superabsorbent material (SAM) are used to increase absorbency, then the absorbency is improved, but the manufacturing process complexity increases

Engineering Contradiction:
ImproveabsorbencyVSAvoidmanufacturing process complexity
Core Design Contradiction:
Quantity of substanceVSDevice complexity

Solution Approach 1:

The patent employs a self-crosslinking binder that automatically forms crosslinks under processing conditions without requiring additional chemical treatments or complex manufacturing steps. The binder material self-assembles and crosslinks during the normal web formation and drying process, eliminating the need for separate bonding operations.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent utilizes changes in processing parameters (temperature, moisture content) to trigger crosslinking of the binder material, allowing the manufacturing process to proceed using standard equipment and conditions. The crosslinking occurs automatically as the web passes through the dryer section, converting the binder from a liquid state to a crosslinked gel state without additional processing steps.

Inventive Principle:
Principle #35Parameter changes

4Quantity of substance

If high concentrations of superabsorbent material (SAM) are used to increase absorbency, then the absorbency is improved, but the mechanical strength deteriorates

Engineering Contradiction:
ImproveabsorbencyVSAvoidmechanical strength
Core Design Contradiction:
Quantity of substanceVSStrength

Solution Approach 1:

The patent creates a composite structure where cellulosic fibers form a mechanical framework that provides tensile strength and structural integrity, while SAM particles are distributed within this framework to provide absorbency. The composite architecture allows each component to contribute its primary function without compromising the other.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The binder material acts as an intermediary that bonds SAM particles to the cellulosic fiber matrix, creating a unified structure where the fibers provide mechanical strength and the binder ensures particle immobilization. This intermediary bonding mechanism allows high SAM concentrations to be incorporated while maintaining mechanical integrity through the fiber-binder-particle network.

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 solution achieves high absorbency with improved liquid handling and mechanical strength, maintaining softness and immobilizing SAM particles effectively in both dry and wet states, suitable for high SAM concentrations beyond 70%.

Implementation Method 1

a self-crosslinking latex binder

Methodology Applied
Scientific EffectAbsorption: Absorption (physical)

Implementation Method 2

The binder material comprises a self-crosslinking latex binder

Methodology Applied
Scientific EffectGel formation: Gel

Implementation Method 3

self-crosslinking latex binder

Methodology Applied
Scientific EffectCrosslinking: Chemical Bonding

Implementation Method 4

thermal treatment to form a particle matrix and induce crosslinking

Methodology Applied
Scientific EffectThermal treatment: Heat Treatment

Implementation Method 5

compaction and thermal treatment to form a particle matrix

Methodology Applied
Scientific EffectCompression: Compression

Implementation Method 6

70-90% SAM, 5-25% interspersed cellulosic fibers

Methodology Applied
Scientific EffectComposite material formation: Composite Materials

Data Source

PatentEP2872097B1Soft absorbent sandwich web comprising high concentrations of superabsorbent material, cellulosic fibers and surface applied binder
Publication Date: 2020.02.05 GLATFELTER FALKENHAGEN GMBH
  • EP2872097B1 patent drawingFigure 1

AI summary

The present invention is a liquid absorbent sandwich web as can be used in absorbent products such as in disposable absorbent articles such as diapers, feminine hygiene articles or incontinence devices, and to the manufacturing of such webs. The liquid absorbent sandwich web provides high absorbent capacity without compromising softness.