Cap Vent

A storage-container manufacturer puts a lid on container leakage and contamination – plus eliminates the need for additional mechanical protection – with a cost-effective, vented closure designed by Porex. The closures, which feature specially laminated membrane materials that are virtually impossible to separate, have been approved for certificated packaging worldwide.

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Design Challenge:
Recent legislation around the world has addressed the quality of storage containers and closures, resulting in greater demands for cost-effective venting systems designed to equalize a container's pressure during transit. To meet these demands, a storage manufacturer contacted Porex to develop and manufacture a thin membrane that could be thermally or ultrasonically welded to a range of plastic materials. Design requirements for the finished vent included resistance to abrasion and the ability to demonstrate consistent two-way venting in use, even after repeated wetting and drying cycles.

Solution:
Porex engineers chose PTFE, with its naturally hydrophobic nature, as the most suitable material to meet the demands of the application. To further increase the strength of the membranes and facilitate welding, Porex engineers developed a proprietary process to laminate a polypropylene mesh backing to a range of base membranes. The bond created between the two materials makes them virtually impossible to separate. In addition, the composite is easy to weld directly to closures--particularly beneficial on automated lines--demonstrates superior resistance to mechanical damage during assembly and use.

Result:
Closures containing the Porex laminate material have been approved for use around the world in certificated packaging. The ability to weld directly to the cap eliminates the requirement and cost for additional mechanical protection. End-users also benefit due the composition of the PTFE surface, which facilitates release of any contamination and helps maintain constant vent rates. Since this vent was developed, Porex has adapted the lamination process for use with different materials and applications in other markets

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