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Polyurethanes are the largest class of polymers worldwide, with a global market of $79 Billion. As a class, it keeps growing.

Breakthroughs in materials science continue to add opportunities for innovation in materials science and global industries. Taking advantage of those opportunities nets great advantages.

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 it 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 that has high compression set resistance and a high degree of 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 on the Hubble space telescope.

All products utilize 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 key properties, recommended usage, pros, and cons.  

Open-Cell Design

Open-cell design is PORON foam's defining trait. PORON foam is a type of foam meant to keep its shape, cushioning, and contouring precisely in response to pressure. Then, when the pressure is released, the cushioning foam will expand to its full size, or until it meets a new pressure point.

This is a method of creating physical memory. Its viscoelastic properties are derived from its microcellular design. 

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 small, closed air bubbles, or pockets. 

Over time, repeated compression causes air to leak out of the closed cells. Once out, the air cannot come back in, because the cells are closed. This process deflates the foam. 

Small Springs

In contrast, open-cell design is more akin to microcellular springs. Compression lets the polyurethane springs condense, and air moves freely from the space rather than being trapped. The remaining air comfortably supports the pressure point within the micro-coils. 

Then, when the pressure eases or lifts, air flows easily back into the open cells, re-inflating the foam. The foam expands, and the pressure point is supported by both air and polymer. 

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, as well as 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's fairly soft and holds its shape well.

Pros

As the lowest-density foam, it can be used as a gap-filler or seal on lightweight products, or within small gaps, without throwing off the item's weight. 

Cons

As the least-dense PORON foam, 4701-15-06 has a Compression Force Deflection rating of 2.00 at 25% kPa. It is not recommended for shock absorption in vehicles. It will not effectively withstand high compression forces. 

We recommend you use this PORON foam as a dust seal, to block out small particle contaminants. It can also cushion and 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. PORON XRD® Impact foam is part of the 4710-30 series. PORON XRD foam in particular is lightweight enough to fit well into apparel. 

Pros

4701-30-20 is highly durable, flexible, and compression set resistant. It also absorbs sound waves and shock waves well. Its softness makes this PORON series useful in delicate applications, like cushioning batteries or electronic components. 

Cons

It is not well-suited for environments with frequent temperature fluctuations. It is also not the densest PORON foam, so it cannot be used in the heaviest-duty applications. For instance,  this PORON foam is not likely to sufficiently dampen industrial noise. 

Recommended Usage 

We recommend you use this PORON foam to reduce noise and mitigate vibration effects. It is an effective tool to dampen automotive noise.  

You will likely want to apply PORON 4701-30 with the most effective adhesive. Especially in more finely-tuned applications, you'll want to ensure your adhesive doesn't add any unnecessary bulk, especially since you're using such a lightweight product.

Aim to thoroughly test and qualify any pressure-sensitive adhesive before application. 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 is designed to protect components from potential water damage, or seal contained water away. The PORON AquaPro Series takes the expansive, space-filling properties of PORON and enhances them with further water-resistant capabilities. 

The density of PORON AquaPro Series foams ranges from 304 kg/m³ to 400 kg/m³

Pros

This series is long-lasting. It retains its set compression over long durations, and it doesn't corrode. Its also environmentally safe, with zero risks of any plastic migration.

The AquaPro Series has been shown to reliably waterproof even the smallest gaps. It seals gasket widths as narrow as 0.5mm. Once sealed, the gaskets are impermeable to water. 

This series does not require a significant degree of compression force to get a tight seal.

It is also flame-retardant. It resists many automotive chemicals.

Cons

The AquaPro™ series is only intermittently stable in high-heat (120ºC) conditions. For high-heat applications, you may want to choose 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 contexts. 

Recommended Usage

The AquaPro™ PORON foam best meets hydrophobic needs. It effectively seals in and secures components that are likely to be exposed to water. Headlights, tail lights, tablets and smartphones, and even electrical outlets mounted outdoors 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 4710-40 Polyurethane

The PORON 4710-40 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. It trades some softness for higher tensile strength than the 4710-30 series. 

This series includes polymer products in a range of densities, from 240 kg/m³ to 480 kg/m³. The series also encompasses a range of thicknesses, from 0.70mm to 12.7mm. 

Pros

The PORON 4710-40 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. 

Cons

The PORON 4710-40 polyurethane series has some drawbacks in some contexts. It is not notably waterproof or anti-bacterial, so its best to choose a different PORON product when sealing off 

Recommended Usage

Due to its high heat tolerance, the PORON 4710-40 series is well used in battery pads. Lithium batteries will not alter the foam, even in the case of an extremely exothermic reaction.

In the same vein, this foam safely seals high-pressure gaskets, even in extreme heat.  

It is also useful in 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. These PORON foams are intended to be vacuum-compressed, creating a solid, airtight seal upon compression. 

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.  

Pros

These polyurethane products resist most chemicals, are safe for the environment, and are durable for long-term performance. These foams meet or surpass low closure-force requirements mandated in certain aviation applications. 


Cons

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 re-used for multiple applications.


Recommended Usage

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 4710-50 line of polyurethane foams is firm. They 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 4710-50 polyurethane products range in density from 240 kg/m³ to 480 kg/m³

Pros

The most notable pros are the energy efficiency, durability, and longevity of this firm foam. 

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.  

Cons

It is not soft. It is also not resistant to all chemical fluids. Be aware that exposure to some chemical fluids may cause the 4170-50 polyurethane to swell. 

 

Recommended Usage

We recommend this industrial polyurethane series for any engineering task that requires firm PORON foam. Firm foam is sturdy. It's useful for vibration management in cars and trains. It is also lightweight and shock-absorbent enough to be a useful cushion in electric vehicles. 

Due to its effective vibration isolation, 4170-50 polyurethane foam can serve a dual purpose, dampening sound and managing impact.

Because it can maintain its integrity so well, this foam is an effective choice for dealing with vibrations, energy, and sound from atypically shaped sources. It will remain molded in its correct form while enduring long-term vibrations. 

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 a long period of time without losing any shape or stiffness. 

This is one of the most durable PORON products. It resists tearing, corrosion, mildew, and bacteria.

Pros

The firmness and resilience of this line makes 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. 


Cons

It is not soft. This makes it unsuitable for cushioning a human body directly. It is also not a good choice to protect 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 when it is in a small space.


Recommended Usage

PORON 4710-60 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 can both 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.

Pros

PORON V-0 foam is the safest PORON foam for humans. It surpasses high standards for flame resistance and durability. It is a firm PORON foam. 

This foam is easy to die-cut with precision. It will retain its shape long-term after being cut. 

Cons

It is not very soft or flexible. It is not notably resistant to mildew or bacteria. This series is not well-suited to contexts where it will be continually exposed to dampness. 

Recommended Usage

PORON V-0 foam is typically used in seat or vehicle cushions. It is also used for gap-filling. In hybrid electric vehicles (HEV), this foam is certified for maximum driver safety and is lightweight enough that it's extremely 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. The foam ranges in density from 240 kg/m³ to 480 kg/m³. 

It is also flexible. The combination of firmness and flexibility allows it to absorb impacts with precision, even in a small space. 

Pros

PORON Shock Seal™ foams are easy to shape and contour. Due to their firmness, these foams can absorb huge shock sound waves. They can dampen high-decibel sound. This brings dangerously loud industrial noise under a threshold safe for human hearing.

This family of foams effectively mitigates frequent, intense, unpredictable shocks.

Cons

The PORON Shock Seal foams are not good for gap filling. They are too firm. Likewise, they are not waterproof or flame retardant. So, we do not recommend using them in cars, aircraft, or electric vehicles.

Recommended Usage 

The PORON Shock Seal family of foams is most frequently used in running shoes, prosthetics, LCD screens, electronics, sound blocking, and isolating vibrations from industrial machinery. 

For shoes and prosthetics, the foam's compression set resistance keeps the interiors comfortable once it's properly shaped.

The thinness of PORON Shock Seal foams let them work effectively in electronics and LCD screens. It keeps screens and displays from cracking if you drop a device by redistributing the impact. 

It also works to effectively seal off dust. This protects the delicate electronic circuitry inside the tablet or phone. 


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.

Pros

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 in a way that is comfortable for most people. It can also be exposed to damp environments, as it is bacterial and mildew-resistant. 

Cons

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 more readily when it absorbs water. This cannot be submerged. Moreover, this foam series is not particularly resistant to automotive fluids. 

Recommended Usage

The PORON 4790-92 foam is predominantly used for gaskets and gap-filling. Its softness enables it to fit completely into small gaps. Its slow expansion ensures every aspect of its surface unfurls precisely into the space you've placed the foam in.

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 touch it (either directly or one layer removed). 

LCD screens, battery pads, cushions, and shoes are typical uses for PORON



PORON EVExtend® 4701-43

The PORON EVExtend® is a material intended to cushion electric vehicle batteries. One unique property of this material 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 a foam that has a firm-to-soft gradient within a single piece. 

These materials are firmer at the front, to maximize their impact-absorbing effects in the direction most impacts come from. Then, the back is softer. The back expands slowly to precisely 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

Pros

PORON EVExtend® is a durable polymer. It will last a long time.

The flat CFD curve is the polyurethane pad's most noteworthy feature. It resolves the problem of creating effective shock absorption in a context where low-density materials are mandatory. 

These materials are halogen-free. They're also UL certified as flame-resistant. 

Cons

The PORON EVExtend® is not waterporrf. It has a highly specific utility, and it is not particularly versatile. It is not typically the best choice for any project beyond interfacing with an electric vehicle battery. 

Recommended Usage 

The most typical usage is as a battery pad inside electric vehicles and hybrids. This material 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 is probably best used with an electric vehicle.

Customized PORON Foam

Which type of PORON foam will you need? Each of the eleven types 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 set and contour 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.

 

Scott Chambers

Written by Scott Chambers

Business Development Manager for Strouse Scott graduated from Coastal Carolina with a degree in Business Management. He then attended the University of Baltimore School of Law earning his JD in 2016. He passed the bar later that year, and he started working for Strouse in 2017. Scott is in charge of marketing and business development in addition to being Strouse's In House Counsel.

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