Foamed heat insulation material, e.g. for tunnel lining, is built up of joined extruded sheets and contains aluminum flakes

摘要

Heat insulation material (11) is made by joining continuous foamed, extruded sheets (4, 5, 6), e.g. 10 to 20 mm thick into a multi-layer structure and then cutting to length. The material, which is polyethylene or polypropylene, contains aluminum flakes smaller than the pore size of the foam, preferably 25% of the pore size, e.g. down to 0.02 mm and thinner than the pore wall thickness.