| 摘要 |
Mouldings, preferably in the form of boards, for use as thermal insulation are produced from a) a finely divided, pulverulent or fibrous substance which has a water absorbtion capacity of from 4 to 50% by weight at 23 DEG C and a relative humidity of 85%, b) a covering comprising two parts having an asymmetrical structure which contains this finely divided, pulverulent or fibrous substance, the first part of the covering being metal-free and being hollowed (thermoformed) in such a manner that this hollow is completely filled by the moulding, preferably in the form of a board, and the second part ("lid") optionally being metal-free or metal-containing and planar and being connected to the hollow in such a manner that a gas- and water vapour-tight seal is ensured, and the two parts having water vapour permeabilities of between 0 and 0.2 g/m<2>/d at 23 DEG C and a relative humidity of 85% and having gas permeabilities for N2, O2 and CO2 of in total 0 to 0.5 cm<3>/m<2>/d/bar at 23 DEG C, with the property of absorbing water up to an amount of from 2 to 15% by weight without its thermal conductivity simultaneously being impaired by more than 25%. |
