When designers need a gasket material that seals reliably at very low closure forces, maintains its shape over time, and conforms to uneven or delicate surfaces, PORON® Soft-Seal is purpose-built for the job. This microcellular polyurethane foam is engineered for thin-profile sealing applications where traditional foams are either too stiff, inconsistent, or prone to permanent set.
What Makes PORON Soft-Seal Different
PORON Soft-Seal is designed for maximum softness and compressibility without sacrificing durability. Unlike open-cell foams that collapse or lose thickness, Soft-Seal maintains a stable cellular structure that rebounds consistently after compression.
Key performance traits include:
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Extremely low compression force deflection (CFD) for gentle, reliable sealing
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Excellent compression set resistance to maintain seal integrity over time
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High conformability, allowing the material to follow curves, steps, and surface irregularities
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PET film backing for dimensional stability, handling strength, and clean converting
In the widely used PORON 4701-15 Soft-Seal series, the polyurethane foam is directly cast onto a 2-mil polyester (PET) backing, creating a permanent bond – similiar to Aqua-Pro PET supported. This backing improves robustness during die cutting, enhances dimensional control, and simplifies assembly in thin or cosmetic-critical applications.
Designed for Thin and Lightweight Devices
Soft-Seal excels in designs where space is limited and sealing pressure must remain low. Available in very thin gauges, it can effectively seal extremely small gaps while avoiding stress on housings, glass, or plastic components.
Common applications include:
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Consumer electronics and handheld devices
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Display and lens gaskets
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Dust and moisture seals in compact enclosures
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Shock-absorbing interface gaskets
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Cosmetic sealing zones where appearance matters
Its softness allows it to perform where rigid materials or higher-force foams would cause distortion or damage.
Improved Soft-Seal: Better Surface Toughness, Better Yields
The Improved PORON® Soft-Seal family adds increased surface toughness while preserving the same softness and compressibility designers rely on. This enhancement significantly reduces foam tearing during liner removal and handling.
Benefits of the improved surface include:
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Higher manufacturing yields
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Easier processing during assembly
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Greater flexibility in adhesive liner selection
Importantly, these gains come without compromising Soft-Seal’s ability to seal at very low forces or conform to complex geometries.
Reliable Sealing Over the Long Term
Soft-Seal is engineered to maintain its shape and sealing performance through repeated compression and long dwell times. Its resistance to compression set helps preserve environmental sealing, block contaminants, and extend the life of the finished product—especially in applications where rework or service access is limited.
Converting and Custom Gasketing
With its PET backing and consistent material structure, PORON Soft-Seal is ideal for precision die cutting, kiss cutting, and complex gasket geometries. It performs well in:
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Tight-tolerance gasket frames
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Multi-cavity layouts
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Ultra-thin sealing profiles
This makes Soft-Seal a strong choice for both high-volume production and high-mix designs that demand repeatability and clean edges.