Stretch Laminate with Low-Basis Nonwoven for Absorbent Articles

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Solution Overview

Problem

Existing stretch laminates used in absorbent articles, such as diapers, face challenges in achieving a balance between fit and cost-effectiveness due to the activation process, which can cause mechanical damage to the elastomer layer, leading to defects like holes and reduced performance.

Innovation Solution

A stretch laminate comprising a skinned or skinless elastomer film with a nonwoven material layer of less than 25 gsm basis weight, attached to the elastomer film, which exhibits high engineering tensile strength at a strain rate of 600/s, reducing the likelihood of damage during activation and allowing for cost-effective production.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the outer layer or layers of stretch laminates are made with good elasticity to accommodate varying body types, then the adaptability is improved, but the inner layer's elastomeric properties are inhibited during activation

Engineering Contradiction:

Improveadaptability to varying body typesVSAvoidelastomeric properties of inner layer

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The stretch laminate is divided into distinct functional layers: an inner elastomer layer providing elasticity and an outer nonwoven layer providing structural support and preventing damage during activation. This segmentation allows each layer to perform its specific function without interfering with the other, resolving the contradiction between adaptability and reliability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention uses a composite structure combining an elastomer layer with a nonwoven layer to create a stretch laminate that achieves both elasticity for body type adaptation and structural integrity during activation. The composite material approach allows the elastomer to provide stretch while the nonwoven layer protects it from mechanical damage.

Inventive Principle:

Principle #40Composite materials

2Reliability

If larger thicknesses or specialty nonwoven products are used for the inner layer to prevent mechanical damage during activation, then the reliability is improved, but the manufacturing cost increases

Engineering Contradiction:

Improveresistance to mechanical damage during activationVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The invention changes the parameters of the nonwoven layer by specifying a basis weight of less than 25 gsm, which provides sufficient protection during activation while avoiding the need for thicker, more expensive materials. This parameter optimization balances reliability with manufacturing cost-effectiveness.

Inventive Principle:

Principle #35Parameter changes

3Adaptability or versatility

If the activation process is applied to enhance elasticity of the laminate, then the adaptability is improved, but mechanical damage such as holes and ruptures occurs in the elastomer layer

Engineering Contradiction:

Improveelasticity of laminateVSAvoidmechanical damage to elastomer layer

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The nonwoven layer is positioned to act as a protective cushion before the activation process occurs. This preliminary protective measure prevents direct mechanical contact between the activation equipment and the elastomer layer, thereby avoiding holes and ruptures while still allowing the laminate to achieve enhanced elasticity.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The nonwoven layer serves as an intermediary between the activation process and the elastomer layer. It absorbs and distributes the mechanical stresses of activation, protecting the elastomer from direct damage while still allowing the desired elastic properties to be achieved in the composite 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 proposed solution enhances the durability and cost-effectiveness of stretch laminates by minimizing mechanical damage during the activation process, enabling the use of thinner elastomer films and less expensive nonwoven materials while maintaining performance.

Implementation Method 1

The elastomer film having an engineering tensile strength, at an engineering strain rate of about 600/s, of at least one of about greater than about 14 MPa for a plain specimen or about greater than about 7 MPa for a notched specimen

Methodology Applied

Scientific EffectTensile strength: Tension

Implementation Method 2

a second layer comprising a nonwoven material, the second layer having a basis weight of less than about 25 gsm and a surface that is attached to the surface of the first layer

Methodology Applied

Scientific EffectAdhesive bonding: Adhesive

Data Source

PatentUS9308130B2Stretch laminate, method of making, and absorbent article

Publication Date: 2016.04.12 PROCTER & GAMBLE CO

AI summary

A stretch laminate includes a first layer including a skinned or skinless elastomer film, the first layer having a surface, and a second layer including a nonwoven material, the second layer having a basis weight of less than about 25 gsm and a surface that is attached to the surface of the first layer. The elastomer film has a strength of an engineering tensile strength, at an engineering strain rate of about 600/s, of at least one of about greater than about 14 MPa for a plain specimen or about greater than about 7 MPa for a notched specimen. A method of making the stretch laminate and an absorbent article having at least one region defined by the stretch laminate are also provided.