Foam

Foams are made with a variety of different polymers and vary in density, color, thickness, and cell structure. By volume, the biggest use of foam is for making beds, cushions and as a packaging material. In smaller volumes, but large quantities, foam is used for gaskets, seals, mounting (with adhesive on both faces), applicators, cleaners, and springs.

In choosing a foam, the first thing to consider is the environment in which the foam is to be used. Such factors as exposure to heat, UV and chemicals must be considered. Harsh environments or the need to resist burning may rule out some foams. Other characteristics such as 'memory' (the ability to return to its original shape after prolonged distortion) might be important also. The 'spring rate' of the foam will be determined largely by its density. Density is usually stated in terms of pounds per cubic foot. Typically a light foam might be 2 pounds, a medium (seat cushion) might be 6 pound, while a heavy foam might be 12 pounds.

Foam can be closed celled (many bubbles stuck together) or open cell (like a sponge or a filter). Open cell foams are often made from closed cell foams that undergo a process called 'reticulation' that breaks open the bubbles while leaving a structure. Open cell foams tend to be much more absorbent.

Most foams are made by mixing chemicals that bubble up and fill a mold. Most foams are made in large 'buns' then sliced into rolls or sheets. The surface of these foams will be the same as the interior of the foam. Some foam is cast or extruded and tend to have a smooth skin which is different from the foam inside. While any foam can be cast to size, it is usually the high performance foams that are made this way.

Foams can be die cut, slit or laminated with PSA or to other parts. The high tech industry uses foam extensively as seals, filters and springs. The medical industry uses foam for mounting and protecting.

This page is not meant to provide a full education on foams, but will give you the factors to think about when specifying your requirement. We can share our resources, and those of our vendors to help you find the right material for your application when you come to us for your converting needs.