Polymeric Netting Calendering for Macroporous Films
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Solution Overview
Problem
There is a need for additional, simple, and economical techniques to produce macroporous layers, including films and sheets, which are commonly used in personal care garments, filtering, and acoustic applications, as existing methods are either complex or inefficient.
Innovation Solution
A method involving the creation of polymeric layers with controlled openings by passing polymeric netting through a nip or calendaring process, where the netting comprises an array of polymeric strands periodically joined at bond regions, allowing for the formation of layers with specific open area ratios and hole sizes, suitable for various applications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If mechanical perforating devices (intermeshing rollers, die punching, needlepunching) are used to create macroporous films, then the film achieves vapor and liquid permeability, but the process becomes complex and costly
Solution Approach 1:
The patent applies preliminary action by incorporating a porous support structure into the film during the extrusion process itself, rather than creating pores afterward through mechanical perforation. The porous support is formed simultaneously with the film matrix, establishing the permeable pathway structure before the film is completed, thus avoiding complex post-processing perforation steps
Solution Approach 2:
The patent merges the film formation process with the porous structure creation by co-extruding the film material and porous support material in a single operation. This combines what were previously separate steps (film extrusion and porous structure creation) into one integrated process, reducing device complexity and manufacturing steps
2Productivity
If thermal zones or lasers are used to melt perforations into the film, then openings are created efficiently, but the equipment complexity and cost increase
Solution Approach 1:
The porous support structure is formed during the extrusion process itself, creating the opening pathways before the film is fully formed and cooled. This preliminary creation of pores eliminates the need for subsequent thermal perforation steps using lasers or heated rollers
Solution Approach 2:
The patent extracts the porous support as a distinct functional component that is integrated into the film structure. By separating the pore-creation function into the support structure formation step, the need for complex thermal perforation equipment is eliminated
3Reliability
If quenching polypropylene into beta phase crystals followed by orientation is used to create porosity, then the film becomes porous, but the process becomes complex and time-consuming
Solution Approach 1:
The porous structure is created during the extrusion process itself through the porous support, eliminating the need for subsequent quenching and orientation steps that are required in conventional polypropylene processing to achieve porosity
Solution Approach 2:
The patent changes the fundamental approach to porosity creation by using a porous support material with inherently open structure, rather than relying on phase transformation and mechanical orientation of polymer crystals. This parameter change from crystalline structure-dependent porosity to support-structure-dependent porosity dramatically reduces processing time
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 method effectively produces polymeric layers with controlled open areas and hole sizes, enhancing their usability in personal care, filtering, and acoustic applications, offering a more efficient and cost-effective alternative to existing techniques.
Implementation Method 1
A method involving the creation of polymeric layers with controlled openings by passing polymeric netting through a nip or calendaring process
Data Source
AI summary
Polymeric layer having first and second, generally opposed major surfaces, comprising an array of openings extending between the first and second major surfaces. The polymeric layers are useful, for example, as components in personal care garments such as diapers and feminine hygiene products. They can also be useful for filtering (including liquid filtering) and acoustic applications.