| abstract |
Composite elements which have the following layer structure: DOLLAR A (i) 2 to 20 mm metal, DOLLAR A (ii) 10 to 100 mm polyisocyanate polyaddition products obtainable by reacting (a) isocyanates with (b) compounds reactive toward isocyanates in the presence of 1 up to 50% by volume, based on the volume of the polyisocyanate polyadducts, at least one gas (c) and optionally (d) catalysts and / or (f) auxiliaries and / or additives, DOLLAR A (iii) 2 to 20 mm metal . |