Hydroformed PLA Nonwoven Web for Softness and Permeability
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Solution Overview
Problem
Existing methods for producing high loft nonwoven materials for absorptive devices, such as diapers and feminine napkins, are costly and inefficient, particularly when attempting to combine a film layer during the spinning process, and PLA materials are prone to destruction under hydroforming stresses, limiting their use in topsheets.
Innovation Solution
A hydroformed expanded spun bonded nonwoven web is created using bicomponent fibers combining polyethylene or other polymers with PLA, which undergoes a process involving pressurized liquid jets to increase loft and air permeability while maintaining a basis weight, and incorporating a surfactant for hydrophilicity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the spunlacing process is used to create high loft nonwoven materials, then softness and coolness are improved, but the process cost and complexity increase
Solution Approach 1:
The patent replaces the mechanical needle entanglement system with a hydroforming system that uses pressurized liquid to expand the nonwoven web. This substitution achieves similar lofting effects without the complexity of needle mechanisms, resolving the contradiction between softness improvement and process complexity
Solution Approach 2:
The patent changes the physical state and parameters of the nonwoven web by applying pressurized liquid during hydroforming. This transforms the web structure to achieve high loft and softness characteristics without requiring complex spunlacing equipment, thereby resolving the contradiction
2Ease of manufacture
If the spunlacing process is used to create high loft nonwoven materials, then air permeability is improved, but production speed decreases
Solution Approach 1:
The patent replaces the slow mechanical needle entanglement process with a faster hydroforming process using pressurized liquid. This substitution maintains air permeability improvement while significantly increasing production speed, resolving the contradiction between air permeability and productivity
3Ease of manufacture
If PLA materials are used in the nonwoven web, then biodegradability is improved, but the material is destroyed under hydroforming stresses
Solution Approach 1:
The patent uses composite materials combining PLA with other polymers to create a nonwoven web that maintains structural integrity during hydroforming. The composite structure allows PLA to provide biodegradability while the combined material resists destruction under hydroforming stresses, resolving the contradiction between biodegradability and material integrity
4Adaptability or versatility
If a film layer is incorporated during the spinning process, then product functionality is improved, but the film layer is damaged by high pressure water jets
Solution Approach 1:
The patent applies preliminary action by incorporating the film layer during the spinning process before hydroforming. This timing allows the film to be integrated into the web structure in a way that protects it from damage during subsequent high-pressure water jet treatment, resolving the contradiction between functionality and film integrity
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 material achieves an average loft of at least 1.3 times and air permeability of at least 1.2 times the original, providing enhanced softness and coolness while being suitable for use as a topsheet in absorptive devices, and surprisingly withstands hydroforming stresses, making it suitable for use with PLA-containing materials.
Implementation Method 1
The spunlacing process for hydro-entanglement of loose fibers. The spunlacing process may create relatively high lofted soft nonwoven materials that are soft and cool to the touch by using high pressure water jets that are essentially in the shape and diameter of needles to hydro-entangle the fibers.
Implementation Method 2
incorporating a surfactant for hydrophilicity
Data Source
AI summary
A hydroformed expanded spun bonded nonwoven has a first substantially planar surface on one side thereof and a second surface on an opposite side thereof. The second surface includes a plurality of protuberances in a pattern. The hydroformed expanded spun bonded nonwoven web has an average loft of at least about 1.3 times greater than an original average loft of an original unexpanded spun bonded nonwoven web from which the hydroformed expanded spun bonded nonwoven web was created and an air permeability of at least about 1.2 times greater than an original air permeability of the original unexpanded spun bonded nonwoven web. The hydroformed expanded spun bonded nonwoven web includes bicomponent fibers combining a polymer with PLA in a ratio of polymer/PLA within a range of about 20/80 to 80/20.