EPDM foam is lighter and more porous than solid EPDM; however, it is still a resilient and long-lasting material that is ideal for industrial applications. A foam EPDM part excels in highly compressive applications as its porous structure is able to offer a tighter seal. EPDM manufacturers are able to dictate the density of a cellular EPDM sheet by applying pressure to the material to create smaller air pockets and reducing pressure for larger air pockets. Although they are porous in nature, EPDM sponge still retains excellent resistance to harsh UV rays, ozone, and oxygen. Although they both retain the same environmental resistance properties, an open and closed cell EPDM part are each generally used for different applications due to their difference in density.

Is EPDM Cellular Rubber?

EPDM is a cellular rubber that is available in open and closed cell forms and it is created when gases are introduced into the material during its production process. Unlike solid EPDM rubber, cellular EPDM is a lightweight and porous material. The difference between the open and closed cell forms of EPDM foam can be seen in their structure. EPDM foam is made up of air pockets that give it a light and airy composition that is better suited for highly compressive applications rather than abrasive or impact heavy applications. Like its solid form, EPDM foam is an extremely resilient material that is often used outdoors or in light to medium-duty applications because, even though it is not abrasion resistant like solid EPDM, it is still highly resistant to damaging environmental factors, abrasive temperatures, and chemical solvents. Both open and closed cell EPDM are used for different applications due to their difference in structures. For instance, “In the closed cell foam, each cell is an independent closed entity…The cells will contain gas if the polymer is impermeable to the gas used for the formation of the of the cellular structure” (sciencedirect.com). On the other hand, “The cells in the open cell foam are interconnected, thus unable to hold gas. Liquids and gases can move through the open cell structures, like through common sponges” (sciencedirect.com). Despite their cellular structure, EPDM foam is still an outstanding outdoor rubber material that will offer long-lasting application in the outdoors.

What is EPDM Sponge?

EPDM sponge is an airy and porous form of EPDM rubber that is available in open and closed cell forms. They are produced as EPDM manufacturers introduce foaming agents to the material to create a light and porous structure; however, the process of making closed and open cell EPDM sponge is different. For closed cell EPDM sponge, “a chemical powder is used. When exposed to heat, the material will decompose. The pressure is then added to the mix and nitrogen gas will be produced. This creates the closed cell sponge rubber’s strength and density.” Contrastingly, for open cell EPDM sponge, the manufacturing process “requires the use of several ingredients that are mixed and then heated in a mold. At this point, sodium bicarbonate will be added. The sponge, which is uncured, will then rise, like a cake, creating interconnected bubbles” (menafn.com). Due to their difference in density, closed and open cell EPDM sponge are used for different applications. Closed cell EPDM sponge retains excellent moisture-resistance properties that allow it to be used in moisture-related applications; however, open cell EPDM is too porous for moisture-related applications and is best used for insulation.

Is EPDM Breathable?

Solid EPDM is not breathable, but EPDM foam is breathable because of its cellular structure; however, breathability levels differ depending on its density and size of the air pockets. EPDM foam is a breathable material due to its air structure; however, the level of permeability differs between open and closed cell. The tight-knit matrix of closed cell EPDM makes it extremely difficult for moisture or air to smoothly permeate through the material. Moisture can eventually seep through the material if left unattended for long periods of time, but air will have to be pressurized for it to penetrate a closed cell EPDM sheet. An open cell EPDM sheet is much more breathable that closed cell due to its larger air pockets. However, if you are looking for breathable products you should be considering materials that are cross-woven and not sheet goods, as discussed here. For example, the highly porous matrix of open cell EPDM allows moisture and air to flow smoothly through the material whereas the density of closed cell EPDM foam prevents the smooth flow of air through the material.

What is EPDM Foam?

EPDM foam is the cellular version of solid EPDM that is differentiated by their porous and air-filled structure. Foam rubber “refers to rubber that has been manufactured with a foaming agent to create an air-filled matrix structure” (Wikipedia.org). A cellular EPDM sheet is best used for thermal, electrical, and noise insulation rather than abrasive industrial applications because they are light and porous compared to solid EPDM. As a case in point, “The main physical properties of foam rubber are generalized as being ‘Lightweight, buoyant, cushioning performance, thermal and acoustic insulation, impact damping, and cost reduction” (Wikipedia.org). Like its solid counterpart, EPDM foam is inherently weatherproof allowing it to be used outdoors without worry of damage caused by UV rays, ozone, and oxidation. Additionally, they also retain a wide operating temperature range allowing them to provide reliable applications even when coming into contact with abrasive temperatures. A cellular EPDM part, despite its lightweight and porous structure, still retain the same resistance properties as solid EPDM with the exception of moisture-resistance for open cell EPDM foam.

Is EPDM Closed Cell?

EPDM is available as a closed cell foam material and it is created when EPDM manufacturers apply pressure as gases are being infused into the material during its production. Closed cell EPDM foam is differentiated by their smaller and tight-knit structure of air pockets. It is a denser material than open cell, but it is still light enough to float on water. One of the key characteristics of closed cell EPDM foam is its excellent resistance to moisture which is made possible by their tight-knit structure. Instead of absorbing the moisture immediately, closed cell EPDM has an absorption level of less than 5% allowing it to keep moisture on its surface longer without seeping through the material. In addition, closed cell EPDM has a wide operating temperature range of -40 to 200 degrees Fahrenheit – just slightly lower than solid EPDM’s range of -40 to 212 degrees Fahrenheit. Due to these properties of closed cell EPDM foam, it is a valued material that is often used in outdoor marine settings.

What is Open Cell EPDM?

Open cell EPDM is an extremely porous material that is made up of large air pockets that can be seen with the naked eye. Open cell EPDM foam is a much more porous and permeable material that is not resistant to moisture and will absorb liquids upon contact. For instance, “Open cell foams fill with whatever gas surrounds them. If filled with air, a relatively good insulator results, but, if the open cells fill with water, insulation properties would be reduced” (Wikipedia.org). Open cell EPDM foam is best used for noise insulation because its highly porous open cell matrix allows the energy of sound to dissipate within its structure to reduce the amount of noise produced. In addition, open cell EPDM foam has an operating temperature range of -40 to 160 degrees Fahrenheit and will not be damaged when coming into contact with abrasive temperatures. Despite its porous and absorbent nature, open cell EPDM is a resilient material that will provide a long-lasting application in industrial settings.

What is EPDM Sheet?

An EPDM sheet is available in both solid and cellular forms and is the material used in the production of industrial EPDM part, such as seals, gaskets, and protective padding. A solid EPDM sheet is best used for heavy-duty applications that receive regular abuse and exposure to chemicals, excessive moisture, and constant and repeated impacts. A solid EPDM part is ideal for protective applications and has the ability to absorb the force of impact and protect surfaces from damage. A cellular EPDM sheet is better suited for highly compressive applications or for thermal and sound insulation rather than abrasive industrial applications. An open cell EPDM sheet is best used for insulation as its extremely porous nature is better able to disperse the energy of sound. On the other hand, due to its absorption level of less than 5%, a closed cell EPDM sheet can be used in moisture-related applications. An EPDM sheet, whether solid or cellular, will offer long-lasting and resilient industrial rubber parts despite the difference in density and structure.

A foam EPDM sheet, both open and closed cell, are often used for applications that require a tighter seal due to its high compressibility. Unlike solid EPDM, EPDM foam is a light and airy material that is created when EPDM manufacturers introduce gases into the material during its production process. Closed cell EPDM foam is a highly moisture resistant material with an absorption level of less than 5%, due to the smaller air pockets that make up its structure, whereas open cell EPDM is highly absorbent. EPDM sponge, like its solid counterpart, is resistant to damaging environmental factors and retain a wide operating temperature range, allowing a foam EPDM part to work well in applications involving abrasive temperatures. Overall, EPDM foam, despite their light and airy structure, is a long-lasting industrial material that is able to withstand highly compressive applications in outdoor and indoor industrial settings.