Extensible Back Ear Laminate for Absorbent Articles
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Solution Overview
Problem
Absorbent articles with high modulus back ears require high force for extension, leading to poor fit and increased risk of skin marking due to non-uniform surfaces and large surface gathers, while low modulus strands result in inadequate extensibility and quality perception.
Innovation Solution
The development of absorbent articles with back ears that exhibit an engineering strain greater than 8% at 2N of force and a roughness of less than 300 μm, achieved through a laminate structure of nonwoven webs and elastomeric materials, ensuring both sufficient extensibility and a smooth surface for comfort.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high modulus back ears are used to maximize sustained fit and minimize leakage, then fit quality is improved, but the force required to extend the back ears increases making them difficult to apply
Solution Approach 1:
The patent changes the modulus parameter of the back ear material from high to low, transforming the material properties to reduce extension force while maintaining fit quality through alternative mechanisms
Solution Approach 2:
The patent uses composite construction with multiple layers including nonwoven fabric and elastomeric materials in specific configurations to achieve the desired balance between extensibility and sustained fit without requiring high modulus materials
2Ease of operation
If low modulus elastic strands are used to reduce extension force, then ease of application is improved, but the surface becomes non-uniform causing skin marking and irritation
Solution Approach 1:
The patent applies different material properties to different regions of the back ear structure, with smooth low modulus elastomeric materials in skin-contact areas and potentially different materials or structures in non-contact areas, achieving both ease of application and skin comfort
Solution Approach 2:
The patent creates a uniform surface structure through careful selection and configuration of materials, ensuring the surface is homogeneous and smooth to prevent skin marking while maintaining the low modulus properties needed for easy application
3Ease of operation
If low modulus strands are used to achieve easier extension, then ease of operation is improved, but the product perception of quality decreases
Solution Approach 1:
The patent achieves homogeneous surface structure through careful material selection and layer configuration, creating a uniform appearance that conveys quality while maintaining the low modulus properties for easy extension
Solution Approach 2:
The patent uses composite material construction with multiple layers including nonwoven fabric and elastomeric materials configured to create a uniform surface structure that enhances perceived quality while maintaining ease of extension
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 a comfortable, secure fit with reduced risk of skin marking and irritation, enhancing the holistic perception of the product by offering noticeable extensibility and a gentle, even surface.
Implementation Method 1
each of the first and second back ears has an engineering strain greater than 8% at about or below 2N of force
Implementation Method 2
one or more nonwoven layers and an elastic material at approximately zero relative strain where the nonwoven layer(s) and the elastic material may be bonded using adhesive
Data Source
AI summary
An absorbent article has a liquid pervious topsheet, a liquid impervious backsheet, an absorbent core disposed between the topsheet and backsheet; first and second opposing longitudinal side edges, a front waist region and a back waist region; and a first and second back ear extending outwardly from the first and longitudinal side edges in the back waist region, respectively. The first and second back ears have an engineering strain greater than about 8% at about or below 2N of force when measured according to the Back Ear Extension Test, and a roughness Ra lower than about 300 μm when measured according to the Roughness Test.