Open-cell Foam Vs. Closed-cell Foam: Which One to Choose?

Jan. 01, 1970

The foam family is a huge group of materials that can be classified in many ways and types. For you, all foam materials can be either closed-cell or open-cell foam.

It may be difficult for you to understand exactly what they mean in a short time. But after reading this article, you will easily know what open cell foam is and what closed cell foam is. Another benefit is that you can understand the comparison between the two different types of foams and can make an informed choice based on your application.

Open-cell polyurethane foam

Foams are versatile, lightweight and durable, making them ideal for use in many industries.

What is open-cell foam?

Here, we will elaborate on some aspects of open cell foam materials.

Polyurethane Foam Tray

Polyurethane foams are one of the most commonly used open cell foams. They are used in a wide variety of industries and materials for insulation, sound insulation and vibration damping applications, including furniture upholstery, seat cushions, medical packaging, electronics, electrical equipment and more. Open-cell polyurethane foams are superior to other forms of insulation because of their dexterity and oxygen resistance.

You may be confused to hear that solids are also made of polyurethane foam. In fact, polyurethane foams come in two forms - open-cell or closed-cell structures, which differ in density and their respective applications. However, in this article, we focus on open-cell polyurethane foam materials.

In addition to polyurethane foams that are also available in open-cell structures, PVC/Nitrile foam and EPDM foam rubber are also available in open-cell foams.

Open-cell EPDM foam

Open-cell foams are exemplified by polyurethane foam sheets, in which the holes within the material have been ruptured, allowing air to occupy the interior space. Open-cell foams are typically lighter in weight and less dense than closed-cell foams, and they have a soft, cushioned, spongy appearance.

During the expansion and curing process of open-cell foam, the air bubbles used in its production are released into the atmosphere, rather than being locked in place as in closed-cell foam. These pores in open-cell foams allow them to interlock and interconnect. Due to this porous nature, open cell foam is not resistant to liquid water or water vapor.

EVA Open Cell Packing

What is open cell foam made of?

There are many different types of open cell foam materials, but they are usually made from polyurethane, reticulated polyurethane, PVC/NBR, EPDM, etc.

Applications for open cell foam

Custom polyurethane foam packaging

Open cell foam can be used for a variety of construction applications, including

Low-cost furniture upholstery

Interior design projects

Building sound insulation

Foam protective packaging

Applications with vapor, moisture and air infiltration requirements

What is closed cell foam?

Closed-cell foam is a strong, flexible plastic-rubber material made up of internal pores or cells. These internal cells of closed cell foam sit tightly together, but are not connected. A closed-cell structure can be compared to a web full of bubbles in which the balloons are trapped tightly against each other, but each bubble is not connected to each other.

Closed-cell foam sheets

In addition, closed cell foam is more commonly used in various industries such as construction, packaging, marine, electronics, and automotive. Typical closed cell foam materials include EVA foam materials, polyethylene foam, neoprene foam, PVC/Nitrile foam rubber, SBR foam rubber, etc.

Anti-static Packing Foam

What is closed cell foam made of?

The materials that can be used to produce closed cell foam vary widely, from EVA, polyethylene, polystyrene, rubber to polypropylene. Closed cell foam consists primarily of trapped air bubbles that form during the expansion and curing of the foam. These bubbles constitute the blowing agent. They are permanently locked in one place because the trapped gas is very effective in improving the insulation capacity of the foam. The foam formed is strong and usually has a medium density, allowing the bubbles to lock into place. The nature of the foam allows it to be flame retardant and resistant to liquid water.

Applications of closed cell foam

Closed cell foams have many applications. They are useful for a variety of applications that require moisture and vibration resistance as well as thermal and acoustic insulation. Closed cell foam as well as sponge rubber products have been very popular for many years in insulation, cushioning, padding and backing applications. The applications for closed cell foam are endless.

It is also used as a way to customize protective foam packaging for the safe storage and display of fragile jewelry, tools, electronics and more. They provide excellent protective cushioning, moisture resistance and air resistance to prevent moisture from collecting in the interior of the package, making them an excellent choice for the safe storage of delicate machinery over long periods of time.