Polyurethanes are the largest class of polymers worldwide, with a global market of $79 Billion. As a class, it’s rapidly expanding.
Breakthroughs in materials science continue to add opportunities for innovation in materials science and global industries, and taking advantage of those opportunities yields a big reward.
Just ask the electric vehicle industry. Top EV companies increasingly use polymer foam as a thermal interface. This keeps powerful Li-ION batteries safe and prevents them from overheating in electric vehicles.
PORON foam is one such groundbreaking material.
Rogers Poron Foam
What is PORON foam?
PORON foam is a microcellular urethane with high compression set resistance and high energy absorption. This foam has an open-cell design, which allows for greater resiliency and longevity, even after multiple impacts.
Rogers Corporation, a global leader in materials development, has patented thirty-five PORON Industrial Polyurethanes. These open-cell polyurethane materials have solved unique engineering challenges, including filling gaps in the Hubble space telescope.
Each of their products utilizes PORON urethane foam's distinct properties differently, to different ends.
The following guide will unpack the utility of PORON foam's open-cell design. Then, we will describe each of the eleven PORON foam products. Each entry will summarize the product's fundamental properties, recommended usage, pros, and cons.
Open-cell design is PORON foam's defining trait.
PORON foam is meant to keep its shape, cushioning, and contouring precisely in response to pressure. These viscoelastic properties are derived from the foam’s microcellular design.
Once the pressure is released, the cushioning foam will expand to its full size or until it meets a new obstacle. This is a method of creating physical memory.
Before the invention of PORON foam, the most popular type of memory foam used a closed-cell design. Closed-cell polyurethane foams use air to provide a cushion. These closed-cell foams are filled with tiny, closed air bubbles or pockets.
Over time, repeated compression causes air to leak out of the closed cells. Because the cells shut it out, air cannot return to the foam. This process of exhalation deflates the foam.
In contrast, open-cell design is more akin to microcellular springs.
Compression lets the polyurethane springs condense, and air moves freely from the space. Meanwhile, the remaining air can support the pressure point within the micro-coils.
After the pressure eases, air can easily flow back into the open cells and -re-inflate the foam. The foam expands, and both air and polymer support the pressure point.
Since open-cell design prevents deflation over time, PORON foam is frequently used in products designed to resist frequent, repeated impact. Running shoes and prosthetic limb interiors are good candidates for PORON foam and other open-cell polyurethane cushions.
Each of the eleven PORON foam varieties uses the same open-cell design to different ends. Some PORON foam products are more thermal resistant and thus make high-quality battery insulators. Others are lightweight and are well-suited for absorbing sound waves.
Here's how the eleven types of PORON foam stack up.
PORON 4701-15-06 (Soft Seal)
This is the lowest-density PORON foam available. Its density is 104 kg/m³. Thickness options include 0.53mm, 0.75mm, and 1.00mm thick. It is relatively soft and holds its shape well.
As the lowest-density foam, you can use it as a seal on lightweight products, or within small gaps, without throwing off the item's weight.
As the least dense PORON foam, 4701-15-06 has a Compression Force Deflection rating of 2.00 at 25% kPa. This PORON variation isn’t recommended for shock absorption in vehicles because it won’t withstand high compression forces.
We recommend you use this PORON foam as a dust seal to block out small particle contaminants or as a cushion to protect small, delicate materials.
PORON Polyurethane 4701-30 Series
This PORON Polyurethane is the softest PORON product. It's highly flexible and easy to compress. Its density is 240 kg/m³. It comes in 4.78mm and 12.70mm thickness varieties.
This series encompasses both PORON 4701-30-20 and PORON 4701-30-25. The impact foam PORON XRD® is part of the 4701-30 series and lightweight enough to fit into apparel.
4701-30-20 is highly durable, flexible, and compression set resistant. It absorbs sound waves and shock waves well. Plus, its softness makes this PORON series useful in delicate applications, like cushioning batteries or electronic components.
PORON 4701-30 isn’t well-suited for environments with frequent temperature fluctuations. It’s also not a very dense PORON foam, so it can’t be used in the heaviest-duty applications. For example, this PORON foam is not suited for dampening industrial noise, but it is an effective tool to dampen automotive noise.
We recommend you use this PORON foam to reduce general noise and vibration effects.
You’ll likely wish to apply PORON 4701-30 with the most effective adhesive. Especially in more finely tuned applications, you want to ensure your adhesive doesn't add any unnecessary bulk, especially since you're using such a lightweight product.
Aim to test and qualify any pressure-sensitive adhesive before application thoroughly. Be sure to choose only low-density PSAs.
PORON® AquaPro™ 4701-37 Series
The PORON® AquaPro™ Series includes 4701-37 Thin, 4701-37-14, 4701-37TS9-19, and 4701-37TS9-25.
This series was designed to protect components from potential water damage and to seal contained water. The PORON AquaPro Series uses the expansive, space-filling properties of PORON and bolsters them with water-resistant capabilities.
The density of PORON AquaPro Series foams ranges from 304 kg/m³ to 400 kg/m³
This series is long-lasting. It retains its set compression over long durations and doesn't corrode. It’s also environmentally safe, with zero risks of any plastic migration.
The AquaPro Series has been shown to reliably waterproof even the most minor gaps. It seals gasket widths as narrow as 0.5mm. Once sealed, the gaskets are impervious to water.
This series does not require a significant compression force to get a tight seal. In addition, it’s flame-retardant and resists many automotive chemicals.
The AquaPro™ series is only intermittently stable in high-heat (120ºC) conditions. For high-heat applications, you may want to select a different PORON foam.
This series is primarily used to seal and waterproof electronics and vehicles. It's not the most shock-absorbent foam, so it is not recommended for maximum-impact scenarios.
The AquaPro™ PORON foam best meets hydrophobic needs. It effectively seals in and secures components that are likely to be exposed to water.
Headlights, taillights, tablets and smartphones, and even outdoor electrical outlets have all benefitted from AquaPro PORON covering gaps.
By filling small spaces, the AquaPro series effectively seals off components to prevent water damage. It meets and surpasses Federal Aircraft Regulation standards for sealants.
PORON 4701-40 Polyurethane
The PORON 4701-40 Polyurethane series encompasses 4701-40-15, 4701-40-20, and 4701-40-30.
This polyurethane foam series is composed of the second softest PORON foams. Some of its softness is traded for higher tensile strength than the 4701-30 series.
This series includes polymer products in various densities, from 240 kg/m³ to 480 kg/m³. The series also encompasses a range of thicknesses, from 0.70mm to 12.7mm.
The PORON 4701-40 polyurethane series can handle extreme temperature fluctuations without warping. This polyurethane can function in temperatures as low as -40ºC and as high as 121ºC.
The density and tensile strength make this foam well-suited for shock absorption. Mechanical shocks, drops, and vibrations are easily absorbed and diffused by this open-cell polymer.
The combination of softness and absorption lends this series to applications cushioning the human body or fragile electronic components.
The PORON 4701-40 polyurethane series has some drawbacks in some contexts. It is not notably waterproof or anti-bacterial, so choosing a different PORON product for sealing is best.
Due to its high heat tolerance, the PORON 4701-40 series is often used in battery pads. Lithium batteries will not alter the foam, even in the case of a highly exothermic reaction.
In the same vein, this foam safely seals high-pressure gaskets, even in extreme heat. It’s also valuable for car interiors, airplane seating, and running shoes.
PORON AquaPro™ Closed-Cell Vacuum Seal (4701-41)
This PORON foam product line differs from everything else on this page because it is the only closed-cell foam.
This series includes PORON AquaPro™ 4701-41-15, 4701-41-20, and 4701-41-30.
These foams are thermally stable at consistent temperatures as low as 40ºC and high as 90ºC. They're intended to be vacuum compressed and create a solid, airtight seal upon compression.
These polyurethanes resist most chemicals, are safe for the environment, and are durable for long-term performance. Most notably, they can meet or surpass low closure-force requirements mandated in specific aviation applications.
As a polymer with a closed-cell structure, it will not revert to an expanded state after it has been vacuum-sealed. It cannot be reused for other applications.
This is an effective waterproof sealant for aircraft and automotive parts. As with the other AquaPro products, it is useful when you want to protect electric components from water.
PORON 4701-50 Polyurethane
The PORON 4701-50 line of polyurethane foams is firm. These foams are made for high-impact, high-energy gaskets.
These PORON foams withstand fluctuating temperatures from -40ºC to 121ºC. They have a high compression set deflection rating and are denser than other PORON foams. The 4701-50 polyurethane products range in density from 240 kg/m³ to 480 kg/m³.
The most notable pros of this firm foam are its durability, longevity, and energy efficiency.
As a firm, somewhat dense polyurethane, it has less "give" than softer foams. This is good when you need a material that will resist moderate impacts and effectively cushion or absorb intense impacts.
PORON 4701-50 isn’t soft or resistant to all chemical fluids. Exposure to some chemical fluids may cause this polyurethane to swell.
We recommend this industrial polyurethane series for any engineering task requiring firm PORON foam. Firm foam is sturdy and useful for vibration management in cars and trains. It is also lightweight and shock-absorbent enough to be a good cushion in electric vehicles.
Due to its effective vibration isolation, 4170-50 polyurethane foam serves the dual purpose of dampening sound and managing impact.
Because it can maintain its integrity, this foam is an effective choice for dealing with vibrations, energy, and sound from atypically shaped sources. It can endure long-term vibrations all while remaining molded in its correct form.
PORON 4701-60 Polyurethane
The PORON 4701-60 is a very firm series of PORON foam. The series encompasses 4701-60-15, 4701-60-20, and 4701-60-25. It can deflect waves and vibrations for an extended period without losing shape or stiffness.
This is one of the most durable PORON products. It resists tearing, corrosion, mildew, and bacteria.
The firmness and resilience of this line make it effective when you need to create or seal a gasket in hot machinery. It also safely absorbs frequent, high-intensity shock waves or sound waves.
PORON 4701-60 is not soft. This makes it unsuitable for cushioning a human body directly or any delicate electronic components.
We do not recommend using 4170-60 to fill small gaps. Its firmness might prevent it from expanding precisely into the necessary shape in a small space.
PORON 4701-60 foams are excellent in extreme environments. Because they can withstand high heat and effectively absorb pressure, we recommend these materials for industrial machine gaskets.
They are also useful for vehicles because they dampen sound and regulate frequent, diverse vibrations.
PORON V-0 Foam
PORON V-0 foam is both HBF and UL94-V-0 certified for passenger safety. It has a density of 400 kg/m³. It functions in temperatures as low as -20ºC and as high as 90ºC.
PORON V-0 foam is the safest PORON foam for humans. It surpasses high standards for flame resistance and durability. It is also a firm PORON foam.
This foam is easy to die-cut with precision. It will retain its shape long-term after being cut.
It isn’t very soft or flexible or notably resistant to mildew or bacteria. This series is not well-suited to contexts where it will be continuously exposed to dampness.
PORON V-0 foam is typically used in seat cushions or for gap-filling. In hybrid electric vehicles (HEV), this foam is certified for maximum driver safety and is lightweight enough to be highly energy efficient.
PORON Shock Seal™ Family
The PORON Shock Seal™ Family of foams includes 4790-79-09, 4790-79-12, 4790-79-15, and 4790-79-20. These foams are sometimes categorized as "display back pad foam" by Rogers Corporation.
PORON Shock Seal™ foam is firm, with a density from 240 kg/m³ to 480 kg/m³
It is also flexible. The combination of firmness and flexibility allows it to absorb impacts precisely, even in a small space.
PORON Shock Seal™ foams are easy to shape and contour. Due to their firmness, these foams can absorb huge shock sound waves and dampen high-decibel sound. This brings dangerously loud industrial noise down into a safe range for human hearing.
This family of foams effectively mitigates frequent, intense, or unpredictable shocks.
The PORON Shock Seal foams are too firm to be any good for gap filling. Likewise, they aren’t waterproof or flame retardant, so we don’t recommend using them in cars, aircraft, or electric vehicles.
The PORON Shock Seal family of foams is most frequently used in running shoes, prosthetics, LCD screens, electronics, sound blocking, and for isolating the vibrations from industrial machinery.
For shoes and prosthetics, PORON Shock Seal™ has a compression set resistance that keeps the interiors comfortable once properly shaped.
The thinness of PORON Shock Seal foams allows them to work effectively in electronics and LCD screens. It keeps screens and displays from cracking if you drop a device by redistributing the impact.
The foam also effectively seals dust, protecting the delicate electronic circuitry inside a phone or tablet.
PORON 4790-92 Polyurethane Foam
The PORON 4790-92 series is an extra soft foam design. It rebounds slowly after any pressure is released.
This soft foam ranges in density from 144 kg/m³ to 480 kg/m³. It can function in temperatures as low as -20ºC and in environments where the maximum temperature reaches 121°C
It ranges in thickness from 0.53mm to 12.7mm thick.
The extra soft nature of this foam extends its life. It also keeps it lightweight while still effectively absorbing low-energy impacts.
PORON 4790-92 can also manage continual low-impact vibrations comfortably for most people. It can also be exposed to damp environments, as it is bacterial and mildew resistant.
The main drawback to the softest PORON foam is its impact limit. It is designed to absorb low-energy impacts only. It is not suitable for large-scale noise or vibration management.
This foam also tends to swell when it absorbs water. It cannot be submerged. Moreover, this foam series is not particularly resistant to automotive fluids.
The PORON 4790-92 foam is predominantly used for gaskets and gap-filling. Its softness enables it to fit entirely into small gaps, and its slow expansion means it will unfurl precisely in the space you've placed the foam into.
It can also be used for battery pads and cushions. It is a comfortable foam to touch, so it works well in contexts where someone will have to feel it (either directly or one layer removed).
LCD screens, battery pads, cushions, and shoes are all typical uses for 4790-92.
PORON EVExtend® 4701-43
The PORON EVExtend® is a material intended to cushion the batteries of electric vehicles. Its most unique property is its flatter compression force deflection (CFD) curve.
This flatter curve works with the battery's natural cycle of contraction and expansion. To absorb and distribute force effectively when the degree of compression is constantly changing, the Rogers corporation developed foam with a firm-to-soft gradient in each individual piece.
These materials are firmer at the front to maximize their impact-absorbing effects in the direction most impacts come from. The softer back slowly expands to cushion the battery.
Due to this gradient, the PORON EVExtend® does not have a consistent density throughout. It functions in temperatures that range from -20ºC to 90ºC.
As a durable polymer, the PORON EVExtend® is guaranteed to live a long life.
The flat CFD curve resolves the problem of creating effective shock absorption in a context where low-density materials are mandatory.
Also, these materials are halogen-free and UL certified as flame-resistant.
The PORON EVExtend® is not waterproof. It isn’t particularly versatile and has a highly specific utility. It is not typically the best choice for any project beyond interfacing with an electric vehicle battery.
The most common use of 4701-43 is as a battery pad inside electric vehicles and hybrids. This foam could potentially be used for filling gaps, gasketing, and sealing. It can also be manipulated into a different type of cushion.
That said, the flat CFD curve is such a unique feature, the product as a whole probably works best when used on an electric vehicle.
Customized PORON Foam
Which type of PORON foam will you need? Each of the eleven kinds of PORON polyurethane has its advantages. PORON foam suppliers recommend a range of products based on your project's needs.
For many engineering projects, PORON foam must be set and contoured precisely to work with the machinery. Precision can be achieved with die-cut shaping. Die-cut PORON foam can be customized to your project's exact needs while, at the same time, keeping the efficiency of mass production.
Die-cut PORON foam is just one customization service we supply here at Strouse.
We know customization needs can vary. No two people want identical things out of their materials. Curious about how to meet your custom industrial materials needs? Let's chat.