Nanoweb Scrim Laminates Pleating Stability
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Solution Overview
Problem
Nanofiber webs in pleated filter structures suffer from poor fiber surface stability and delamination issues during the pleating process, leading to unacceptable pleating quality and reduced filtration efficiency.
Innovation Solution
A nanofiber layer with a surface stability index of at least 5 kN/m, combined with a substrate layer, is produced using the electroblowing process, which enhances the bond strength between the nanoweb and the scrim, allowing for pleating without additional modifications such as adhesive or ultrasonic bonding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If conventional nanofiber web techniques are used, then fiber production is achieved, but fiber surface stability is poor leading to delamination during pleating
Solution Approach 1:
The patent applies parameter changes by modifying the electrospinning process parameters (voltage, flow rate, collection distance) to control fiber morphology and surface properties. This results in nanofiber webs with enhanced surface stability that can withstand pleating without delamination, directly resolving the contradiction between fiber production and surface stability.
Solution Approach 2:
The patent creates a composite structure by combining the nanofiber web with a scrim substrate. This composite construction provides mechanical support and anchoring for the nanofibers, preventing delamination during pleating while maintaining the filtration benefits of the nanofiber layer.
2Reliability
If a second scrim is added to prevent delamination (SNS structure), then delamination is reduced, but product thickness increases limiting pleating density
Solution Approach 1:
The patent extracts the delamination prevention function from the second scrim and integrates it into the nanofiber web itself through improved electrospinning techniques. This eliminates the need for the additional scrim layer while maintaining delamination resistance, thereby reducing overall product thickness and enabling higher pleating density.
3Strength
If adhesive or ultrasonic bonding is used to bond scrim to nanoweb, then bond strength is improved, but manufacturing cost and process complexity increase
Solution Approach 1:
The patent applies self-service by designing the nanofiber web to inherently bond to the scrim substrate through the electrospinning process itself. The fibers naturally anchor into the scrim during collection, creating a strong bond without requiring additional adhesives or ultrasonic bonding equipment, thus reducing manufacturing cost and process complexity.
Solution Approach 2:
The patent merges the nanofiber web formation and scrim bonding operations into a single electrospinning step. The nanofibers are deposited and bonded to the scrim simultaneously during the electrospinning process, eliminating separate bonding operations and reducing overall manufacturing complexity.
4Stability of the object's composition
If nanofiber web basis weight is increased to improve stability, then fiber stability improves, but filtration efficiency and pleating density are reduced
Solution Approach 1:
The patent uses parameter changes in the electrospinning process to produce nanofibers with optimized surface properties and morphology. This allows the use of lower basis weight nanofiber webs (0.5-5 gsm) that maintain high stability and resistance to delamination, thereby enabling higher pleating density without sacrificing stability.
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 enables the retention of superior filtration properties while ensuring the nanoweb layer remains stable and intact during pleating, maintaining pleat integrity and increasing pleating density without adding cost or thickness to the filter medium.
Implementation Method 1
These structures provide liquid solutions of the polymer that are then attracted to a collection zone by a high voltage electrostatic field. As the materials are pulled from the emitter and accelerate through the electrostatic zone, the fiber becomes very thin
Data Source
AI summary
A filter media comprising a nanofiber layer and a substrate layer; the nanofiber layer comprising a polymer material and having a fiber diameter of about 0.01 to 1.0 micron, a basis weight of about 0.5 to 30 gsm, and a thickness of at least about 2 microns, the nanofiber layer further having a surface stability index of at least about 5 kN/m, the media further being pleated.