High Loft Nonwoven Web 3D Fiber Recovery
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Solution Overview
Problem
Conventional non-woven webs formed by spunbonding or meltblowing lack recovery when compressed, leading to reduced thermal and acoustical insulation properties, as they are primarily two-dimensional with fibers oriented only in the x and y directions, making them unsuitable for compact shipping and storage.
Innovation Solution
A process for creating a high loft, non-woven web with fibers oriented in the x, y, and z directions using a Spun-Blown® die, which involves a die with multiple nozzles emitting filaments that are directed through a convergent passage formed by heated moving surfaces, resulting in a 3-dimensional structure with V, U, or C-shaped fibers that provide excellent recovery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional spunbonding or meltblowing processes are used to form non-woven webs, then the webs can be produced with a two-dimensional fiber structure, but the webs lack recovery capability when compressed and lose thermal and acoustical insulation properties
Solution Approach 1:
The patent applies dimensionality change by transitioning from a conventional two-dimensional fiber arrangement (x-y plane) to a three-dimensional structure that incorporates z-direction fiber orientation. This is achieved through a specialized die design with nozzles arranged in multiple rows at different heights, allowing fibers to be deposited in a stacked configuration that creates vertical (z-axis) orientation. The resulting V, U, or C-shaped fiber structures extend through the thickness of the web, providing dimensional stability and recovery capability when compressed, as the z-oriented fibers act as structural supports that resist compression and enable the web to return to its original thickness.
2Reliability
If the web is compacted or compressed during shipment, then transportation efficiency is improved, but the web loses its ability to recover to original thickness and thermal/acoustical insulation properties
Solution Approach 1:
The three-dimensional fiber structure with z-direction orientation provides structural integrity that maintains insulation properties even when the web is compacted for transport. The V, U, or C-shaped fibers create a scaffold that resists complete compression, allowing the web to be shipped in a reduced volume state while retaining the ability to recover its full thickness and insulation performance upon arrival.
Solution Approach 2:
The patent incorporates dynamic recovery capability through the elastic nature of the V, U, or C-shaped fiber structures. When the web is compressed during shipping, these structured fibers deform but maintain their structural integrity. Upon release of compression, the fibers elastically rebound to their original configuration, dynamically restoring the web's thickness, porosity, and thermal/acoustical insulation properties without permanent deformation.
3Ease of operation
If fibers are oriented only in x and y directions, then the web structure is simpler to form, but the web becomes hard and stiff when compressed and lacks drapeability
Solution Approach 1:
The addition of z-direction fiber orientation creates a three-dimensional network that prevents the web from becoming overly stiff when compressed. The vertical fibers act as spacers and structural supports that distribute compression forces throughout the web thickness, preventing localized hardening. This dimensional structure maintains flexibility and drapeability while providing sufficient strength, as the multi-directional fiber network can deform and redistribute stresses more effectively than a planar structure.
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 web exhibits a recovery value of 20% to 99% after compression, maintaining its thermal and acoustical insulation properties, and can be compactly shipped without losing material properties, suitable for applications like bedding, upholstery, and filtration.
Implementation Method 1
The pair of heaters is capable of heating the pair of moving surfaces to an elevated temperature below the melting temperature of the polymer
Implementation Method 2
introducing a molten polymer to a die having 2 to 20 rows of nozzles with each row containing a plurality of nozzles. The molten polymer is emitted through the plurality of nozzles to form a plurality of filaments
Implementation Method 3
Air or gas streams are then used to facilitate downward movement of the plurality of filaments
Data Source
AI summary
A process for forming a high loft, nonwoven web is disclosed. The process includes introducing a single molten polymer to a die having a plurality of nozzles. Emitting the molten polymer through the nozzles to form a plurality of filaments. Using air streams to facilitate movement and drawing of the filaments. Directing the filaments, which are transformed into fibers, towards a pair of heated moving surfaces. The pair of heated moving surfaces forming a convergent passage having an entry and an exit. Depositing the fibers into the entry of the convergent passage and routing the fibers between the pair of heated moving surfaces in a machine direction to form a high loft, non-woven web. The web having a fiber size distribution of from 0 μm to about 15 μm with at least about 25% of the fibers being above 4 μm.