Flexible Solutions

Imagine going 65 mph in your vehicle while on a road trip. The road you are driving on is old, so your vehicle bobs up and down the many dips and divots; your speakers are loud and are causing your rearview mirror to vibrate, making it hard to see; and your moon roof has a roaring noise sneaking through the cracks. These foul disturbances are examples of NVH, also known as Noise Vibration Harshness.

Marian sales engineers are experts in designing high quality parts for any small, complex applications. Below, you will find links to two of our newest success stories that highlight laminated foam materials in two very different markets (LED lighting and automotive). In both stories, you will find that Marian's team of experts worked closely with customers to design a unique part, and provided exceptional material recommendations to create a winning solution. Sales engineers must be strategic in choosing materials to ensure that they meet all requirements of the design.

Marian has a brand new demonstration piece to share with the world! Strategically named "Test My Memory," the demo illustrates the impact of compression cycling over time with 4 different foams. Neoprene, Polyethelyne, PORON Urethane, and BISCO Silicone are tested by being compressed for 48 hours.

Foam Material Compression

In the demonstration, you will see that certain foams depreciate as they take on impact over time, whereas other foams resist the compression set by returning to their original thickness. The material characteristic of being able to take a compression set, also called compression force defection, is extremely important in long-term sealing applications. The ability of the material to "push back" to fill in any potential gaps that would allow water or dust to pass through is critical. This makes such materials an excellent option for sealing gaskets. We wrote an entire blog post about compression force defection, you can read it here: Compression Force Deflection in Foam Gaskets: A Critical Property

Compression Force Deflection

Applications that experience periodic compression cycling over time may require a gasket that is capable of compression rebound. In the event that your application uses a material that does not resist compression force, the material may depreciate over time. When your gasket has dwindled or has deteriorated from all of the periodic compression cycling, your gasket will become ineffective and will need to be replaced. In a perfect world, your gasket should rebound to fill any potential gaps. Using a material with great compression resistance will guarantee a long-term sealing performance that will work just as effectively each time you reseal your application.

Ingress Protection (IP) Rating is a common international test method (IEC 60529) to rate enclosure protection from objects and liquids.  

Why is an IP Rating important?  

UL, CSA and CE Mark Standards often require certified products to hold a specific IP rating. Some examples of such products include IT equipment, laboratory equipment, electronic measurement equipment, plus anything claiming to be "dust tight" or "water-resistant", etc. These terms indicate that a device is able to operate successfully in harsh environments with potentially wet and dusty conditions. The IP rating scale provides a range of two numbers that indicate the level of protection provided.

The IP Rating looks like this:  IPXX

1.  The first number indicates protection from solid objects or materials

2.  The second number indicates protection from liquids

For example, an enclosure that is rated IP54 is dust-protected. It will allow limited ingress of dust with the operation of the equipment for two to eight hours. The enclosure is also protected against water splashed from all directions, limited water ingress permitted.

PVC (Vinyl) Foam is the last foam variety that we will explore in our blog series "Foams for Low Clamping Force Seals".  Polyvinyl Chloride (PVC) Foam is a lightweight closed-cell foam material. It is often used for sealing out water, dirt, and air. It resists weathering and is often laminated with adhesive to create a dynamic foam tape. 

XLPE Foam or Cross-linked Polyethylene Foam is the next material we will explore in our blog series, Foams or Low Clamping Force Seals. XLPE Foam is an extremely fine closed-cell material formed of polymers or molecules that are chemically bonded together (cross-linked). The strength of these microcellular molecule bonds is reflected in the strength of the material. XLPE foam can stretch, bear loads, and return to its shape. It works well in insulation, gap filling, and gasket applications that require thicker foam. It can also be used for packaging and medical device packaging. It can be made in a variety of colors, the most common being black, white, and gray.   

Light Density Polyester and Polyether Urethane Sponges and Foams have an open cell structure. The evenly spaced structure of these materials and a high proportion of open cells make them suitable for an infinite number of applications. The open-cell structure makes it highly flexible and conformable compared to its closed-cell counterpart. 

Check out a related blog post: Open-Cell or Closed-Cell Foam, Which is Best?

As we explore different categories of foams that are used for Low Clamping Force Seals in this blog series, we move to Closed Cell Neoprene and Sponge Blends. As stated in the previous post, closed-cell sponge and foam materials do not allow air and moisture to pass through, making them good materials for general sealing and gasketing applications. Keep reading for additional features and benefits of these materials. 

What is Closed Cell EPDM Sponge?

Closed Cell EPDM Sponge is the third material we will explore in our blog series:  Foams for Low Clamping Force Seals.  EPDM stands for Ethylene Propylene Diene Monomer. "Closed Cell" describes the material at a microscopic level. The material is made with tiny bubbles that are inflated with gas, resulting in a closed cell structure that will not allowing moisture to pass through. This is what makes this material excellent for sealing and gasketing. EPDM is commonly used in the automotive and construction industries for various seals and gaskets due to its excellent environmental factors such as UV, Ozone and weathering. When comparing EPDM to Silicone, EPDM falls short when it comes to temperature resistance.

Features and Benefits of Closed Cell EPDM Sponge

• Non-crystalline material. Contains no plasticizers that can migrate and lead to premature membrane failure.
• Can be formulated in a variety of combinations with other polymer modifiers.
• Performs well in the -40°F to 175°F temperature range.
• Excellent moisture resistance, does not absorb fluids easily
• Used in many applications that require water, UV, ozone, or indirect sunlight resistance (superior to neoprene in this regard)
• Does not meet UL flame rating without additives and will not withstand oil and fuels.