Polyester Foam was the first foam to be produced and manufactured commercially.
Subsequently it’s younger brother, polyether foam, became the better known of the 2 foam types from the polyurethane family, the question often asked today is when is the right time to consider using polyester foam?
The most obvious feature of polyester foam is its regular cell structure, and with a high proportion of closed cell windows which glisten in the light, it has the better aesthetics of the two foam types. Alongside its more stable resistance to light ageing from UV light, polyester foam is a natural choice for presentation packaging and case inserts. Most frequently in this application polyester foam will be charcoal grey in colour, and in addition to the many shaping options available, it can be supplied in convoluted or egg-box profile.
That high proportion of closed cell windows also means that polyester foam is more suited to environments where sealing and low air permeability are required, for example as a sealing gasket.
It’s the higher tensile strength of polyester foam in applications where tear strength is important which sets it apart from polyether foam. Where polyether foam will ultimately break down and degrade, polyester foam has the better mechanical strength to keep performing.
It’s that regular cell structure in polyester foam which lends itself to the reticulation process, which renders the foam block completely open cell. The open cell reticulated polyester foam is available in a range of tightly controlled cell sizes, and makes an ideal air filtration media. Cell sizes are available in a range from 2 to 110 PPI (Pores Per Inch).
Moreover, reticulated polyester foam can be compressed into predetermined sheet thicknesses. This process is known as felting. Felted foam has a highly controlled cell structure and is typically used for reservoiring and metering liquids and fine powders.