Medical Foam, Packing Foam, Sealing Foam Supplier|Munk Foam Technology
Home Products Contact Us
Home  >  About Us  >  News

Closed Cell Foam Vs. Open-cell Foam

Sep. 09, 2022

The family of foams is a large category that can be defined in many ways and shapes. Any foam material can easily be an open-cell foam or a closed-cell foam.


In a very short time it may be difficult to understand what they are. However, after reading this report, you will easily understand what open cell foam is and what closed cell foam is. You can see how the two different forms of foam compare to each other and make an informed choice for your application, which is another benefit.


What are open cell foam cells?

One of the most commonly used open cell foams is polyurethane foam. They are commonly used for insulation, sound insulation and vibration damping applications in a variety of industries and products, including furniture upholstery, seat cushions, medical packaging, electronics, electrical equipment and more. Open cell polyurethane foams are superior to other types of insulation due to their dexterity and oxygen resistance.

EVA Filter Foam With Open Cell

 EVA Filter Foam With Open Cell

You may be confused by the fact that polyurethane foams are usually made from solids. The truth is that polyurethane foams come in two types of open-cell or closed-cell structures, which vary in density and application. However, in this article we will focus on open-cell polyurethane foams.


In addition, open-cell structures can also be supplied with polyurethane foams. For open-cell foams, PVC/Nitrile foam and EPDM foam rubber can also be used.


EPDM foam open-cell

Open-cell foams are exemplified by polyurethane foam sheets, which indicate that the cells within the substance have split, allowing the internal space to be filled with air. Compared to closed-cell foams, open-cell foams are usually lighter in weight and smaller in size and have a smooth, cushioned and sponge-like appearance.


The air bubbles used in their development are released into the atmosphere as the open-cell foam expands and cures, rather than being frozen in place as is the case with closed-cell foams. Inside the open-cell foam, these pores allow them to interlock and interconnect. Due to this porosity, liquid water or water vapour cannot be resisted by open-cell foams.

EVA Open Cell Packing

 EVA Open Cell Packing

What is a closed cell foam?

Solid, flexible plastic-rubber materials that consist of internal pores or cells are closed-cell foams. These internal cells of closed cell foam sit closely together, but are not related. A web full of bubbles, in which the balloons are trapped tightly against each other, can be compared to a closed cell structure, but each bubble is not interconnected.


Closed cell foam from various industries such as construction, packaging, marine, electronics and automotive is now being used more frequently. EVA foam, polyethylene foam, neoprene foam, PVC/Nitrile foam rubber and SBR foam rubber are some of the common closed cell foam products.


Open cell foam versus closed cell foam

A porous product is a foam material. The configuration of its cells, and in particular the content of its cells, whether open or closed, will have a significant impact on the output and final application of the product.


Although open cell and closed cell foams may have a similar appearance, they should be considered as two distinct items due to their completely different properties and performance.


While closed cell foams contain over 90% closed cell, for open cell foams this figure is usually less than 20%, although it may be higher, but there is no official description. It is true that open and closed cell foams share some common characteristics, such as shock absorption, thermal insulation and sound deadening. In general, the distinguishing feature is the "closed cell content (CCC)" which specifically affects the basic properties of the foam. The foam, for example tear strength, thermal conductivity, average density, water absorption and water tightness, vapour permeability or compressive strength.


Polyurethane Foam Tray

Polyurethane Foam Tray      

The main differences between open-cell and closed-cell foams are as follows.

Structure of the foam 

The most obvious difference between closed cell and open cell foams is obviously the different foam structures. Using small closed pores, closed cell foams are formulated and present a good, robust appearance. Open-cell foams, however, present an irregular and light-weight appearance, so that open holes around the open-cell foam material can be easily detected.


Foam density

Compared to open-cell foams, closed-cell foams are usually heavier. Closed-cell foams have a closed-cell structure and they retain their initial weight almost until foamed, but open-cell foams cannot cope with this. After the foaming process, the open-cell structure releases a large part of its weight.


Moisture, wind and liquid resistant

When you want to distinguish between closed-cell and open-cell foams, you can take another quick and intelligent approach. It's as simple and quick as pouring some water over both types of foam material. Suddenly, you will find that one form of foam will absorb water and carry it into the small cells. But the rest will not absorb water from their surface and retain it. So you may now know that the first is an open-cell foam and the other is a closed-cell foam.


The voids cross each other in the open-cell foam, forming channels through the solid. Closed-cell foams consist of separate closed areas, so that this foam cannot be penetrated by air or liquids. In the face of liquids such as moisture, water and air, they have a different output due to their foam structure.

Previous Next
 Positioner Foam
Endoscope Cleaning Foam
Suction Swab
Sponge Brush
Sincere Service

Get Free Sample