M2 Products - the Foam Board Factory
M2 Products - the Foam Board Factory
M2 Products - the Foam Board Factory

Sign & Display Foam Board

Making the right choice

In the graphic market, the current choice is between Polystyrene ( PS ) and Polyurethane (PU) foam board products. The end-user should be made aware of the principal technical and structural differences between the two products.

PU foam is formed by reacting a polyol ( a polymeric alcohol with more than two reactive hydroxyl groups per molecule) with diisocyanates of polymeric isocyanates ( e.g. MCI or TDI) . There are significant health and environmental hazards associated with the synthesis of polyurethane polymers and the diisocyanate intermediates due to their toxicity and that of the phosgene used to produce the diisocyanate.

Health effects of isocyanate exposure during manufacture include irritation of skin and mucous membranes, chest tightness, and difficult breathing. Isocyanates include compounds classified as potential human carcinogens and known to cause cancer in animals. The main effects of hazardous exposures are occupational asthma and other lung problems, as well as irritation of the eyes, nose, throat, and skin.

When PU is burnt, one of the degradation products is HCN ( hydro cyanide gas) , which in very small concentrations causing respiratory distress and in higher concentrations produces death by cyanide poisoning.

On a technical front, the closed-cell structure of PS give the foam a "memory" which enables it to recover its form after compression. The open-cell structure of PU means that it does not have this "memory" and the foam remains compressed. This difference is evident when die-cutting: PS foam can be cut with a straight-edged die and gives a clean edge, whilst PU foam gives a compressed edge , a "domed" effect, unless specially serrated die-cuts are constructed , with a specific rubber cutting mat.