Sekisui foaming oven for polyolefin foams

Comparison of Radiation and Chemical Cross-Linking Processes for Producing Polyolefin Foams 

Item Radiation Cross-Linking Chemical Cross-Linking 

Cost Decreases with production volume Relatively constant 

Blowing agent selection Easier More difficult 

In the Toray process, the foamable sheet is expanded as it floats on the surface of molten salts and is heated from the top by infrared lamps. The mol-fen salt mixture consists of potassium nitrate, sodium nitrate, and sodium nitrite. The salt residues from the surface of the foam are blown off by hot air and stripped in water. The Toray process is suitable to produce cross-linked PP foam sheet as well as polyethylene foam sheet. In fact, Toray was the first one to produce commercial PP foam.  

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