Low Basis Weight Nonwoven Core Wrap for Absorbent Articles

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Solution Overview

Problem

Current absorbent core wraps in disposable diapers face challenges in reducing basis weight below 10 gsm due to irregularities like wrinkling, which leads to manufacturing inefficiencies and line stops during high-speed production.

Innovation Solution

Incorporating a fatty acid amide melt additive as a slip agent in the nonwoven fibers to reduce the static coefficient of friction, allowing for a multilayer nonwoven core wrap with a basis weight of 6-10 g/m², thereby minimizing wrinkling and improving production efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of moving object

If the basis weight of the nonwoven bottom layer is reduced below 10 gsm to save material costs and reduce diaper weight, then material cost and product weight are improved, but wrinkling occurs during high-speed production causing manufacturing defects and line stops

Engineering Contradiction:
Improvediaper weightVSAvoidwrinkling
Core Design Contradiction:
Weight of moving objectVSManufacturing precision

Solution Approach 1:

The patent applies parameter changes by modifying the coefficient of friction parameter of the nonwoven bottom layer through the incorporation of fatty acid amide slip agents. This changes the surface properties of the material to reduce friction between layers during high-speed production, preventing wrinkling even at low basis weights below 10 gsm.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The fatty acid amide slip agent acts as an intermediary substance between the nonwoven fibers. It reduces the static coefficient of friction by creating a lubricating effect on the fiber surfaces, allowing layers to slide smoothly over each other during production without generating wrinkles or foldovers.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Loss of substance

If the basis weight of the nonwoven bottom layer is reduced below 10 gsm to reduce material costs, then material cost is improved, but the occurrence of foldovers and line stops increases

Engineering Contradiction:
Improvematerial costVSAvoidproduction efficiency
Core Design Contradiction:
Loss of substanceVSProductivity

Solution Approach 1:

The patent changes the friction parameter of the nonwoven material by incorporating slip agents, enabling the use of lower basis weight materials (6-10 gsm) without sacrificing production efficiency. This parameter modification prevents the material from wrinkling and folding during high-speed converting operations.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The fatty acid amide slip agent serves as an intermediary that facilitates smooth material flow during production. It reduces inter-layer friction to levels that prevent foldovers and line stops, thereby maintaining high productivity even with reduced material thickness and weight.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Shape

If a low basis weight nonwoven is used to make the diaper thinner and more comfortable, then wearer comfort and product thinness are improved, but the material becomes prone to wrinkling and abrasion during handling

Engineering Contradiction:
Improvediaper thicknessVSAvoidresistance to wrinkling
Core Design Contradiction:
ShapeVSStrength

Solution Approach 1:

The patent modifies the surface friction parameter of the thin nonwoven material by adding slip agents. This allows the material to maintain its low thickness (basis weight 6-10 gsm) while gaining resistance to wrinkling and abrasion through reduced friction during handling and production.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The fatty acid amide slip agent acts as a protective intermediary between the thin nonwoven layers and external forces. It reduces the static coefficient of friction to prevent wrinkling and abrasion during handling, preserving the integrity of the thin material structure.

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 use of fatty acid amide melt additives effectively reduces wrinkling and abrasion, enabling the production of low-basis-weight absorbent core wraps that maintain integrity and reduce manufacturing costs by preventing foldovers and line stops.

Implementation Method 1

a fatty acid amide melt additive is used to reduce the coefficient of friction of the nonwoven

Methodology Applied
Scientific EffectLubrication: Lubrication

Data Source

PatentEP3372212B2Absorbent core wrap with a low basis weight nonwoven in the bottom layer
Publication Date: 2022.08.31 PROCTER & GAMBLE CO
  • EP3372212B2 patent drawingFigure 1~2
  • EP3372212B2 patent drawingFigure 3
  • EP3372212B2 patent drawingFigure 4

AI summary

An absorbent article (20) comprising an absorbent core having an absorbent material (60) enclosed in a core wrap having a top layer (16) and a bottom layer (16'). The bottom layer of the core wrap comprises a nonwoven comprising synthetic fibers, which has a basis weight from about 6 g/m2 to about 10 g/m2 and the nonwoven has a static coefficient of friction as measured in cross-machine direction of no more than 0.40.