Abstract: Thermally stable rigid foams based on isocyanate can be produced by reacting a) polyisocyanates with b) compounds containing at least two hydrogen atoms which can react with isocyanate groups, c) water, in the presence of d) physically acting blowing agents, in the presence or absence of e) catalysts and auxiliaries and/or additives, wherein the component b) comprises bi) at least one polyether alcohol having a functionality of at least 1.5 and a hydroxyl number of from 10 to 100 mg KOH/g in an amount of from 0.2 to 80% by mass, based on b), and bii)at least one polyester alcohol in an amount of from 5 to 90% by mass, based on b), the water c) is present in an amount of at most 2% by mass, based on the sum of the components b) to e), and the component d) used comprises hydrocarbons and/or fluorine-containing hydrocarbons in an amount of from 5 to 30% by mass, based on the sum of the components b) to e).

Abstract: A process for producing pipes illustrated with foams comprises [a] providing, between an inner carrier pipe and an outer pipe arranged parallel thereto, a holder which is provided with at least one aperture and is mounted so that it can be moved axially and positions the carrier pipe in the outer pipe and [b] introducing into the vacant space between the two pipes, via the aperture (s) in the holder, a mixture for the preparation of foams, where [b1)] during the introduction of the mixture, the holder moves in an axial direction with respect to the outer pipe and the carrier pipe, then [c] after the mixture is charged, it is reacted to give the foam and [d)] the holder and, if desired, the outer pipe are removed.

Abstract: In a process for producing rigid polyurethane foams by reactinga) polyisocyanatesb) compounds containing at least two hydrogen atoms capable of reacting with isocyanate groups, in the presence ofc) catalysts,d) blowing agents and, if desired,e) further auxiliaries and/or additives,the component b) comprises at least one recycled polyol which is formed by glycolysis of polyurethanes.

Abstract: A process for producing pipes insulated with foams comprises providing, between an inner carrier pipe and an outer pipe arranged parallel thereto, a holder which is provided with at least one aperture and is mounted so that it can be moved axially and positions the carrier pipe in the outer pipe and introducing into the vacant space between the two pipes, via the aperture(s) in the holder, a mixture for the preparation of foams, where during the introduction of the mixture, the holder moves in an axial direction with respect to the outer pipe and the carrier pipe, then after the mixture is charged, it is reacted to give the foam and the holder and, if desired, the outer pipe are removed.