PORON® Gaskets
PORON® is a microcellular polyurethane foam manufactured by Rogers Corporation and widely regarded as the industry benchmark for compression set resistance in gasket and sealing applications. Unlike conventional foams that lose sealing force over time, PORON gasket material maintains consistent closure force and dimensional stability across long service life and repeated temperature cycling. Its fine-pitch open cell structure delivers effective dust, air, and light sealing. And, with the right grade and compression, PORON gaskets can also seal against moisture and water ingress.
Gasket and Seal Fabricators is your source for custom PORON gaskets, seals, and die-cut parts. We stock 4701 and 4790 series materials across a full range of densities and thicknesses, and fabricate precision parts to your exact specifications using die cutting and flash cutting. PORON is low-outgassing, plasticizer-free, and non-corrosive to adjacent metals across the full product line, with select grades also offering inherent flame retardancy. These properties make it an ideal gasket material for electronics, automotive, industrial, and HVAC applications. Available with or without pressure-sensitive adhesive (PSA) backing.
PORON® Gasket Materials We Work With
PORON® polyurethane foams are available in a wide range of firmness levels, densities, and thicknesses to match virtually any gasketing or cushioning requirement. Below is a detailed look at the PORON grades we work with most. Every material listed is available as raw sheet stock or as custom-fabricated gaskets. We offer standard die cutting and flash cutting, and can work from your CAD files or reverse-engineer existing parts.
PORON® 4701-30 (Very Soft)
PORON 4701-30 is the softest grade in the 4701 series, engineered for applications that require effective sealing with minimal compression force. Its ultra-soft, highly resilient cell structure conforms readily to irregular surfaces and thin cross-sections, making it well-suited for electronic display gaskets, LCD sealing, gap filling, and vibration damping in portable electronics and sensitive assemblies. 4701-30 is available in densities of 20 and 25 lb/ft³ (320 and 400 kg/m³) with standard thicknesses from 0.031″ to 0.500″.
Compliance: UL 94 HBF, FMVSS 302, low outgassing.
PORON® 4701-40 (Soft)
PORON 4701-40 is a soft, versatile foam and one of the most widely used PORON grades for general-purpose gasketing and sealing. It delivers a broad range of compression performance, making it suitable for portable electronics, automotive, aerospace, HVAC, and appliance applications where balanced softness and sealing force are required. 4701-40 is available in densities of 15, 20, and 30 lb/ft³ (240, 320, and 480 kg/m³), with typical compression force-deflection values of 5, 11, or 25 psi at 25% deflection. Standard thicknesses range from 0.031″ to 0.500″. Available in both unsupported and PET-supported grades for added dimensional stability.
Compliance: UL 94 HBF, FMVSS 302.
PORON® 4701-50 (Firm)
PORON 4701-50 is a firm grade foam designed for managing high-energy impact and for gaskets that require elevated closure force. It provides excellent compression set resistance and long-term dimensional stability, even under prolonged temperature cycling. 4701-50 is commonly specified for enclosure gaskets, EV battery pads, automotive gap filling, and LCD display fixation where a firmer seal is needed. Available in densities of 15, 20, and 30 lb/ft³ (240, 320, and 480 kg/m³) with compression force deflection values of 10, 17, or 39 psi. Standard thicknesses range from 0.012″ to 0.500″, including PET-supported options.
Compliance: UL 94 HBF, FMVSS 302.
PORON® 4701-60 (Very Firm)
PORON 4701-60 is one of the firmest grades in the 4701 series, engineered for energy management and high closure force gasketing in demanding environments subject to heat, vibration, dust, dirt, and shock. Its high compression force deflection, ranging from 36 to 93 psi depending on density, makes it the preferred choice for heavy-duty enclosure sealing and applications where maximum resistance to compression is required. 4701-60 is available in densities of 15, 20, and 25 lb/ft³ (240, 320, and 400 kg/m³) with standard thicknesses from 0.031″ to 0.250″.
Compliance: UL 94 HBF, FMVSS 302.
PORON® 4790-92 (Extra Soft, Slow Rebound)
PORON 4790-92 is an extra-soft, slow-rebound foam designed for very low closure force gasketing and cushioning applications. The slow recovery characteristic allows the material to conform to mating surfaces under minimal load, making it an excellent choice for battery pads, display protection, gap filling, and shock absorption where gentle, sustained contact pressure is needed. 4790-92 is available across a wide density range of 9 to 30 lb/ft³ (144 to 480 kg/m³) with standard thicknesses from 0.021″ to 0.500″. Its conformable open cell structure returns to its original shape over time, supporting long-term sealing performance.
PORON® 4790-79 (Display Back Pad Foam)
PORON 4790-79 is a firm, ultra-thin microcellular foam engineered specifically for vibration management and shock absorption in portable electronic devices. Its thin profile is available from just 0.004″ to 0.012″ (0.10 mm to 0.30 mm) and it absorbs and distributes impact energy to protect displays from cracks and damage caused by drops or mechanical shock. 4790-79 is available in densities of 15 to 30 lb/ft³ (240 to 480 kg/m³) and is commonly used as a display back pad, LCD stabilizer, or thin-profile cushion in smartphones, tablets, and handheld instruments. Performance characteristics may support applications designed to meet UL 50E, UL 508, and FMVSS 302 Requirements.
PORON® Gasket Material Grades at a Glance
Grade |
Firmness |
Density Range |
Thickness Range |
CFD @ 25% |
Primary Applications |
|---|---|---|---|---|---|
4701-30 |
Very Soft | 20–25 lb/ft³ | 0.031″–0.500″ | Very Low | Display gaskets, gap filling, vibration damping |
4701-40 |
Soft | 15–30 lb/ft³ | 0.031″–0.500″ | 5–25 psi | General-purpose gasketing, electronics, HVAC |
4701-50 |
Firm | 15–30 lb/ft³ | 0.012″–0.500″ | 10–39 psi | Enclosure gaskets, EV battery pads, high-energy impact |
4701-60 |
Very Firm | 15–25 lb/ft³ | 0.031″–0.250″ | 36–93 psi | Heavy-duty enclosures, energy management |
4790-92 |
Extra Soft | 9–30 lb/ft³ | 0.021″–0.500″ | Very Low | Battery pads, cushioning, low closure force sealing |
4790-79 |
Firm (Thin) | 15–30 lb/ft³ | 0.004″–0.012″ | 1–16 psi | Display protection, shock absorption |
Finding the Right Fit
Not sure which grade is right for your application? Start with two questions: how much compression force is available in your assembly, and what does the gasket need to seal against?
For enclosures with rigid frames and consistent bolt loading, firmer grades like 4701-50 and 4701-60 deliver high closure force and strong resistance to compression under load. Where clamping force is limited (snap-fit housings, battery covers, or lightweight enclosures) softer grades like 4701-30 and 4790-92 conform to mating surfaces and seal effectively without requiring heavy fastening.
Applications that fall in between, such as general-purpose electronics and HVAC enclosures, are typically well served by 4701-40, the most widely specified grade in the PORON line.
Thickness and density also affect performance. Thinner gaskets reduce stack height in compact assemblies, while higher-density options within the same grade increase sealing force and durability. All PORON grades can be supplied with pressure-sensitive adhesive backing for simplified assembly, and every grade die-cuts cleanly for tight tolerances and repeatable part quality.
If you’re unsure which grade fits your application, our technical team can help you match the material to your flange conditions, environmental requirements, and production needs.
One Call, Complete Solutions
Talk to our technical team about selecting the right PORON grade, fabrication options, and pricing for your project.
