Resilient Laminate Diagonal Interface for Stress Resistance
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Solution Overview
Problem
Existing laminates used in disposable clothing and medical applications, such as nappies and elastic bandages, face challenges in large-scale production and durability under stress, particularly in securing the nappy around a baby's waist.
Innovation Solution
A laminate structure comprising a stack of non-woven layers with an intermediate layer formed by coextrusion of elastic and rigid films, where the interface curve between the films is specifically designed to create a diagonal line with peak and hollow points, ensuring a strong junction between the rigid and elastic parts, enhancing resistance to stretching and stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional laminate structures are used, then production is simpler, but resistance to stretching and stress deteriorates
Solution Approach 1:
The laminate combines a non-woven layer with a coextruded layer containing both rigid and elastic film sections. This composite structure integrates materials with different mechanical properties (rigid for strength, elastic for flexibility) to achieve superior resistance to stretching and stress while maintaining structural integrity.
Solution Approach 2:
The coextruded layer features locally differentiated zones: rigid film sections provide structural support and stress resistance where needed, while elastic film sections provide flexibility and stretchability in other areas. This local variation in material properties optimizes the overall performance without requiring complex multi-layer structures.
2Strength
If the interface curve is optimized for strength, then resistance to stresses improves, but manufacturing precision requirements increase
Solution Approach 1:
The interface between rigid and elastic film sections is designed as a curved line rather than a straight boundary. This curvature allows for gradual transition and stress distribution, enhancing junction strength while being more tolerant to manufacturing variations compared to sharp angular transitions.
Solution Approach 2:
The interface curve extends diagonally across the laminate structure, creating a three-dimensional stress distribution pattern. This diagonal orientation distributes stresses across multiple dimensions, reducing concentration at any single point and thereby strengthening the junction between rigid and elastic sections.
3Reliability
If elastic and rigid films are coextruded, then durability under stress improves, but production complexity increases
Solution Approach 1:
The rigid and elastic films are merged into a single coextruded layer, creating an integrated structure where both material types are bonded together during the extrusion process. This merging eliminates the need for separate lamination steps, adhesive applications, and alignment procedures, thereby simplifying production while maintaining durability.
Solution Approach 2:
The coextruded layer serves multiple functions simultaneously: it provides structural support through rigid sections, flexibility through elastic sections, and inherent bonding between layers through the extrusion process. This multi-functionality consolidates what would otherwise require multiple separate components and assembly steps.
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 laminate provides excellent resistance to stresses and ensures secure fastening, maintaining elasticity and durability, even when stretched, thereby improving the performance of elastic tabs in nappies and similar applications.
Implementation Method 1
the layer being obtained by coextrusion of the at least two elastic and rigid films
Implementation Method 2
fixed in particular by means of adhesive, in particular glue, to at least one non-woven layer
Implementation Method 3
at least one elastic section in the form of a film extends and at least one rigid section in the form of a film made from a less elastic material
Data Source
AI summary
The invention relates to a resilient laminate comprising, in a vertical direction, a stack of at least one nonwoven layer and a ply consisting of a part or integral part attached to the at least one nonwoven layer, in particular by means of an adhesive such as glue, the ply comprising at least one resilient film area and at least one so-called rigid film area made of a material that is less resilient than the material of the resilient area, in particular an area made of a non-resilient material, the ply being produced by the coextrusion of the at least one resilient film and the at least one rigid film, such that an interface is formed therebetween, characterized in that, from a cross-sectional view, the curve or line formed by the interface between the two films comprises at least one first substantially rectilinear segment, and at least one second substantially rectilinear segment which is angled relative to the at least one first segment. The curve or line formed by the interface between the two films extends from a point (P0) on the lower face of the laminate to a point (P1) on the upper face of the laminate, said points being horizontally offset in relation to one another and the diagonal line passing through said two points being inclined in relation to the vertical to the laminate.