Process for the preparation of polyurethane systems

摘要

The invention relates to a process for the preparation of polyurethane systems, in particular homogeneous 2- or multicomponent systems with a long shelf life which cure rapidly, for the production of, in particular, rigid polyurethane foams of greatly reduced combustibility, which are suitable for the manufacture of lightweight multilayer elements. The object comprises the preparation of the suitable 2- or multicomponent system. The essence of the invention consists in that the polyol mixture has a hydroxyl content of at least 22 % and a nitrogen content of from 1.2 to 3.0 %, without including the flameproofing agent. The content of heteroatoms in the polymer structure of the rigid polyurethane foam must satisfy the relationship % of phosphorus and % of bromine/3 and % of chlorine/12 = 1.7, where the % of phosphorus is not zero.