Pulpless Absorbent Core Using Elastic Strands for SAP Control

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Solution Overview

Problem

Conventional absorbent core forming processes face challenges in balancing air flow and vacuum to retain pulp within the core forming pocket, leading to inefficiencies and limited adjustability, and high concentrations of superabsorbent materials are difficult to control and maintain, especially in thinner diaper designs.

Innovation Solution

The method involves creating a pulpless absorbent core with elastic strands stretched and coupled to a nonwoven layer, allowing for controlled superabsorbent polymer distribution and expansion, using a combination of elastic and nonwoven layers to form a stretchable core that assists in liquid retention and distribution, and can be adjusted for directional stretch and SAP delivery.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional air laying techniques with pulp are used to form absorbent cores, then the cores provide good liquid distribution, but the process requires complex balancing of air flow and vacuum, and has limited adjustability

Engineering Contradiction:
Improvecontrol over SAP distributionVSAvoidair flow and vacuum balancing
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The invention extracts and removes the pulp component from the traditional air laying process, forming a pulpless core structure. This eliminates the need for complex air flow and vacuum balancing that was required to control pulp distribution, while maintaining the ability to distribute SAP uniformly through the simplified nonwoven substrate approach.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention replaces the complex pneumatic system (air flow and vacuum balancing) with a simpler mechanical deposition process. SAP is applied directly to the nonwoven substrate in a controlled manner, eliminating the need for sophisticated air handling systems while achieving precise SAP distribution.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Quantity of substance

If high concentrations of superabsorbent materials are used in thinner diaper designs, then absorbency is improved, but the materials are difficult to control and maintain

Engineering Contradiction:
Improveconcentration of superabsorbent materialVSAvoidcontrol and maintenance of SAP
Core Design Contradiction:
Quantity of substanceVSManufacturing precision

Solution Approach 1:

The invention applies SAP locally to specific regions of the nonwoven substrate where it is needed, rather than attempting to distribute high concentrations uniformly throughout a pulp matrix. This localized application to the porous nonwoven structure allows for better control and maintenance of SAP in thinner diaper designs.

Inventive Principle:
Principle #3Local quality

3Strength

If conventional pulp-based cores are used, then the cores provide structural integrity, but they increase product bulk and weight

Engineering Contradiction:
Improvestructural integrity of coreVSAvoidweight of absorbent core
Core Design Contradiction:
StrengthVSWeight of moving object

Solution Approach 1:

The invention extracts and removes the pulp material from the core structure, retaining only the essential nonwoven substrate that provides structural integrity. This elimination of excess pulp material significantly reduces the weight and bulk of the absorbent core while maintaining sufficient structural strength through the engineered nonwoven architecture.

Inventive Principle:
Principle #2Taking out (Extraction)

4Adaptability or versatility

If more elastic material is used to improve fit and stretch, then product fit is improved, but costs increase and product feel deteriorates

Engineering Contradiction:
Improvestretch and fit of diaperVSAvoidcost and product feel
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The invention changes the parameters of the elastic material itself, using lower-cost elastic materials with modified properties that still provide adequate stretch and fit. The pulplless core structure enables these parameter changes by reducing overall bulk, allowing the elastic to function effectively without compromising fit or incurring higher costs.

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

This approach enables better control over superabsorbent material distribution, reduces waste, and provides a flexible, thin absorbent core that maintains performance and fit, allowing for lower-cost elastic materials and improved product feel and functionality.

Implementation Method 1

elastic strands stretched and coupled to a nonwoven layer

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

superabsorbent polymer material provided in gaps between adjacent elongated elastic members

Methodology Applied
Scientific EffectAbsorption: Absorption (physical)

Implementation Method 3

superabsorbent polymer (SAP) may be added to the pulp core

Methodology Applied
Scientific EffectSwelling: Hydrogel

Data Source

PatentEP3179971B1Pulpless absorbent core and method of core forming
Publication Date: 2020.06.17 JOA CURT G INC
  • EP3179971B1 patent drawingFigure 1A~2B
  • EP3179971B1 patent drawingFigure 3A~4B
  • EP3179971B1 patent drawingFigure 5~7

AI summary

A pulpless core is provided with flexibility for superabsorbent expansion by using elastic strands stretched and coupled to a nonwoven layer, and then relaxed partially to create receiving valleys (puckers) and the puckers are provided with superabsorbent polymer, and then a layer of nonwoven or acquisition film can be coupled on top of nonwoven/elastic/sap carrier layers to create an absorbent core laminate.