Elastic Laminate Tensile Strength via Preliminary Lamination
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Solution Overview
Problem
Existing elastic laminates for disposable pant articles suffer from decreased tensile strength and puncture resistance due to the activation process, which breaks and destroys the non-elastic cloth-like layers, making them prone to tearing when put on or removed, especially for female wearers or caregivers with long fingernails.
Innovation Solution
A method for producing an elastically stretchable three-layer laminate by incremental stretching a first non-elastic fibrous nonwoven web with an elastic film, followed by stretching and laminating it with a second non-elastic nonwoven web, while controlling the degree of stretching and bonding to enhance tensile strength and puncture resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the activation process is used to render the laminate elastically stretchable, then the elasticity of the laminate is improved, but the tensile strength and puncture resistance of the laminate deteriorates
Solution Approach 1:
The non-elastic nonwoven web is laminated to the elastic film in advance, before the activation process. This preliminary bonding ensures that the nonwoven web is already attached to the elastic film before the incremental stretching occurs, so that during activation the nonwoven web reinforces rather than weakens the structure. The nonwoven web acts as a protective layer that maintains tensile strength and puncture resistance even after the elastic film is activated through stretching.
2Adaptability or versatility
If the non-elastic cloth-like layers are broken during activation, then the elasticity of the laminate is improved, but the material becomes prone to tearing when put on or removed
Solution Approach 1:
The laminate is constructed as a composite material combining an elastic film layer with a non-elastic nonwoven web. The nonwoven web is specifically chosen to have high tensile strength and puncture resistance properties. When laminated together, the composite structure allows the elastic film to provide stretchability while the nonwoven web provides structural integrity and resistance to tearing during application and removal of pant articles.
3Ease of operation
If the laminate is made soft and breathable, then the comfort properties are improved, but the tensile strength decreases
Solution Approach 1:
The laminate structure assigns different functions to different layers: the elastic film layer provides softness, breathability, and comfort properties for skin contact, while the non-elastic nonwoven web layer provides the structural strength and tear resistance. This local differentiation of material properties allows each layer to excel at its specific function without compromising the overall performance of the laminate.
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 resulting laminate exhibits significantly improved tensile strength and puncture resistance, reducing the risk of material tearing when putting on or removing pant articles, and maintaining a soft, breathable, and textile-like feel.
Implementation Method 1
In order to render the laminate elastically stretchable, it is subjected to an activation treatment. A three-layer, activated laminate is disclosed in International Patent Application No. WO 03/047488. The activated laminate is produced by incrementally stretching an elastic film layer between two non-elastic cloth-like layers.
Implementation Method 2
The non-elastic cloth-like layers are fully or partially broken or torn during the activation process so that the elasticity of the laminate after activation is mainly governed by the elasticity of the elastic film layer.
Data Source
AI summary
A method for producing an elastically stretchable laminate having at least three layers, the method including the steps of: a) producing a first laminate having a first non-elastic fibrous nonwoven web and an elastic film; b) activating the first laminate by incremental stretching in at least one activation direction to render the first laminate elastically stretchable; c) stretching the activated first laminate to 10-200% in the activation direction; and d) laminating the stretched first laminate to a second non-elastic nonwoven web. An elastically stretchable laminate produced in accordance with the method is also disclosed.