Flameproof and thermostable insulating coatings for hollow bodies and a process for their preparation

The invention relates to a method for producing insulating coatings for hollow bodies. Said insulating coatings have polyurethane and/or polyisocyanurate groups, and are produced by reacting a) one polyisocyanate component with b) at least two compounds with hydrogen atoms which are active towards isocyanates and c) catalysts, optionally in the presence of d) other auxiliary agents and additives. The inventive insulating coatings are characterised in that organic or mineral hollow microspheres with an average particle size of between 5 and 200 mu m and a density of between 0.1 and 0.8 g/cm are added to at least one of the components a) to d). The invention also relates to the use of the inventive insulating coatings for pipes used in offshore applications.