| 摘要 |
<p>In door elements comprising a rigid polyurethane foam (I) between covering layers, (I) is obtained from aromatic polyisocyanates, a polyol component and a radiation-protecting additive (II) comprising (a) gadolinium, (b) barium, indium, tin, molybdenum, niobium, tantalum, zirconium or tungsten and optionally (c) bismuth or rare earth metals other than gadolinium. In door elements comprising a rigid polyurethane foam (I) between covering layers, where (I) is obtained by reacting aromatic polyisocyanates with a polyol component (having on average at least two isocyanate-reactive groups and containing polyether and/or polyester polyols), a radiation-protecting additive (II), blowing agents and optionally catalysts, auxiliaries and/or additives, (II) comprises (by weight) (a) at least 26% gadolinium, (b) 10-74% barium, indium, tin, molybdenum, niobium, tantalum, zirconium or tungsten and (c) 0-64% bismuth, lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, terbium, dysprosium, holmium, erbium, thulium, ytterbium or lutetium. Independent claims are included for the preparation of the door elements.</p> |
