CD-Extensible Nonwoven Composite for Low-Force Cross-Machine Stretch
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Solution Overview
Problem
Existing stretchable nonwoven composites require excessive force to extend in the cross-machine direction, and methods like intermeshing grooved rolls can be costly and damaging.
Innovation Solution
A nonwoven composite with a necked spunbond web oriented in the machine direction, achieving a 4:1 or more ratio of machine direction to cross-machine direction tensile strength, allowing for high elongation and low load in the cross-machine direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If intermeshing grooved rolls or discs are used to stretch composites, then low force extensibility is achieved, but the nonwoven web facing is damaged and cost increases
Solution Approach 1:
The patent changes the physical and chemical parameters of the polymer fibers by incorporating elastomeric polymers with specific glass transition temperatures and molecular weights, transforming the nonwoven fabric from a rigid structure to one with inherent elastic properties that allow low-force extension without damage
Solution Approach 2:
The patent creates a composite nonwoven material by combining traditional polymer fibers with elastomeric polymer fibers, where the elastomeric component provides the necessary extensibility and recovery properties while the traditional fibers maintain structural integrity
2Strength
If traditional nonwoven composites are used, then structural integrity is maintained, but excessive force is required to extend in cross-machine direction
Solution Approach 1:
The patent modifies the mechanical parameters of the nonwoven fabric by controlling the glass transition temperature, molecular weight, and composition of elastomeric polymers, enabling the material to exhibit low-force extensibility in the cross-machine direction while preserving structural integrity through optimized fiber composition and bonding
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 composite exhibits excellent extensibility in the cross-machine direction with low tension, maintaining elasticity and recovering to its original dimension upon force release.
Implementation Method 1
the nonwoven fabric exhibits a peak elongation in the cross-machine direction of about 100% or more and experiences a load at 100% elongation in the cross-machine direction of about 450 grams-force per inch or less
Data Source
AI summary
A nonwoven composite that has a dimension in a machine direction and a cross-machine direction is provided. The composite comprises a nonwoven facing positioned adjacent to an elastic film. The nonwoven facing contains a spunbond web that is formed by necking a base spunbond web. The base spunbond web includes a plurality of fibers generally oriented in the machine direction and exhibiting a machine direction tensile strength and cross-machine direction tensile strength. The ratio of the machine direction tensile strength to the cross-machine direction tensile strength is about 4:1 or more.