Elastic Laminate Puckering and Embedding for Stretching Limit
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Solution Overview
Problem
Existing elastic laminates used in disposable sanitary articles face challenges in achieving cost-effectiveness and maintaining structural integrity while providing reliable and comfortable fit, as they tend to be overstretched and partially destroyed during activation, leading to a lack of perceived stretching limit.
Innovation Solution
A method for producing an elastic laminate involves stretching a top layer of nonwoven transversely using intermeshing ring rolls, puckering it, and then connecting it to an elastic film in a way that the top layer is embedded in the polymer matrix of the film, primarily at line-shaped portions, to maintain structural integrity and provide a clear stretching limit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the laminate is overstretched during activation to achieve elastic recovery, then the stretchable top layer becomes permanently deformed and partially destroyed, but the laminate can be further stretched too easily during use without a clear stretching limit
Solution Approach 1:
The top layer is pre-stretched and puckered during the lamination process before the elastic film is applied. This preliminary action creates permanent deformations and destroys weak fibers in advance, so that during subsequent use the laminate cannot be stretched beyond its designed limit without causing damage. The puckered structure serves as a built-in stop mechanism that prevents overstretching.
Solution Approach 2:
The method intentionally damages the top layer structure beforehand through controlled overstretching during lamination. This beforehand cushioning creates a sacrificial element that absorbs excess stretch energy, preventing the elastic film from being overstretched during use and ensuring the laminate maintains its structural integrity and provides clear feedback to the user about stretching limits.
2Strength
If the top layer is connected to the elastic film only by portions to maintain structural integrity, then production costs increase and manufacturing complexity increases
Solution Approach 1:
The method combines the stretching, puckering, and lamination operations into a single integrated process step. The top layer is stretched and puckered while simultaneously being laminated to the elastic film in one continuous operation, eliminating the need for separate stretching and lamination steps. This merging of operations maintains structural integrity while simplifying manufacturing.
Solution Approach 2:
The lamination process serves multiple functions simultaneously: it bonds the top layer to the elastic film, creates the puckered structure, and establishes the stretching limit all in one operation. This multi-functionality reduces the number of process steps and equipment needed, making production simpler while maintaining the structural benefits of portion-by-portion connection.
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 method results in a cost-effective elastic laminate with improved structural integrity and a clear stretching limit, enhancing user comfort and reliability by preventing unintended overstretching and destruction during use.
Implementation Method 1
the elastic film is at least incipiently melted on its side facing the first top layer
Implementation Method 2
the inserted material is lengthened in a transverse direction so that the stretchable but inelastic top layer of nonwoven is overstretched, permanently deformed
Data Source
AI summary
A method for producing an elastic laminate with at least a first top layer and an elastic film, wherein the first top layer is fed along a production direction to a first stretching device, is subsequently stretched transverse to the production direction by means of the first stretching device and is puckered, and is either connected to an extrusion web provided for forming the elastic film such that the top layer is connected to the extrusion web only by portions facing the melt web or is connected to a pre-produced elastic film in that the elastic film is at least incipiently melted on its side facing the first top layer, the first top layer is pressed against the at least incipiently melted side of the elastic film only by portions, and is therefore at least partially embedded in a polymer matrix of the elastic film.