Multilayered Elastic Laminates with Coextruded Elastomeric Film

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Solution Overview

Problem

Conventional elastic laminates used in personal care products rely heavily on non-woven facing materials for strength and appearance, which increase costs and do not effectively distribute strain, leading to potential breaking and blocking issues during processing.

Innovation Solution

Multilayered elastic laminates comprising a thermoplastic elastomeric film layer and a plastic layer, coextruded and stretched to enhance strength and elasticity, with a facing material, such as a cellulosic material, to achieve a cloth-like appearance and reduced material usage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If non-woven facing materials are used to provide strength and appearance, then mechanical strength and cloth-like appearance are improved, but cost increases and strain distribution deteriorates

Engineering Contradiction:
Improvemechanical strengthVSAvoidmaterial cost
Core Design Contradiction:
StrengthVSQuantity of substance

Solution Approach 1:

The patent uses a composite structure consisting of an elastomeric film layer and a non-woven facing material layer bonded together. The elastomeric film provides elasticity and strength, while the non-woven facing provides appearance and additional strength. This composite structure allows the elastomeric film to bear more of the mechanical load, reducing the strain burden on the facing material and enabling cost reduction by using less or lighter facing material.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent applies different materials with specific properties to different functional requirements: the elastomeric film layer is designed with high elasticity and strength properties to bear mechanical loads and provide stretchability, while the non-woven facing material is designed to provide cloth-like appearance and comfort. This local optimization of material properties allows each layer to perform its specific function efficiently.

Inventive Principle:
Principle #3Local quality

2Strength

If non-woven facing materials are used to provide strength, then mechanical strength is improved, but elasticity and stretchability deteriorate

Engineering Contradiction:
Improvemechanical strengthVSAvoidelasticity
Core Design Contradiction:
StrengthVSAdaptability or versatility

Solution Approach 1:

The patent creates a composite laminate where the elastomeric film layer (providing elasticity) and non-woven facing material layer (providing strength) are bonded together. The elastomeric film layer, made from polymers like polypropylene or polyethylene with specific molecular structures, provides the necessary stretchability and recovery, while the facing material provides structural strength. Together, they achieve both strength and elasticity that neither material could provide alone.

Inventive Principle:
Principle #40Composite materials

3Reliability

If more non-woven facing material is used to prevent breaking, then reliability is improved, but cost and basis weight increase

Engineering Contradiction:
Improvebreak resistanceVSAvoidbasis weight
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The patent employs a composite structure where the elastomeric film layer serves as the primary load-bearing component for preventing breaking during overstretching. The facing material, bonded to the elastomeric film, provides additional strength but at reduced quantities. This composite approach allows the elastomeric film to absorb and distribute strain more effectively, enabling the use of less facing material while maintaining or improving break resistance.

Inventive Principle:
Principle #40Composite materials

4Productivity

If conventional elastic laminates are used for high speed processing, then productivity is maintained, but elastic film blocking occurs

Engineering Contradiction:
Improveprocessing speedVSAvoidfilm blocking
Core Design Contradiction:
ProductivityVSObject-generated harmful factors

Solution Approach 1:

The patent modifies the surface properties of the elastomeric film layer through the bonding interface with the non-woven facing material. This creates localized differences in surface characteristics that reduce friction and prevent blocking during high-speed processing. The non-woven facing material acts as a release layer at the bonding interface, allowing the elastic film to feed smoothly through processing equipment without blocking.

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

The solution provides enhanced mechanical strength and elasticity, shifting the strain burden from the facing material, reducing costs, and achieving a desirable cloth-like appearance while maintaining flexibility and comfort in personal care products.

Implementation Method 1

The layers may be coextruded together

Methodology Applied
Scientific EffectCoextrusion: Extrusion

Implementation Method 2

stretched and then relaxed, providing the resulting elastic laminates with enhanced overall strength and elasticity

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Implementation Method 3

stretched and then relaxed

Methodology Applied
Scientific EffectStress relaxation: Stress Relaxation

Implementation Method 4

a thermoplastic elastomeric film layer affixed to a facing material and a plastic layer

Methodology Applied
Scientific EffectAdhesive bonding: Adhesive

Data Source

PatentEP3188904B1Multilayered elastic laminates with enhanced strength and elasticity and methods of making thereof
Publication Date: 2024.10.09 KIMBERLY CLARK WORLDWIDE INC
  • EP3188904B1 patent drawingFigure 1

AI summary

Stronger elastic laminates, as well as methods of preparing the laminates, are disclosed herein. Particularly, the present disclosure is directed to multilayered elastic laminates including a thermoplastic elastomeric film layer and a plastic layer coextruded together, and further, a facing material laminated to the thermoplastic elastomeric film layer. The laminates are stretched and then relaxed. The prepared laminates have enhanced overall strength and elasticity while having a soft, cloth-like feel, and are prepared at a lower cost.