Abstract: A process for preparing rigid expanded materials containing urethane and optionally urea and isocyanurate groups, characterised in that a polyurethane rigid foam is prepared by reactinga) an aromatic polyisocyanate withb) a polyol component with on average at least 3 hydrogen atoms which can react with isocyanates, containing1) 30 to 80 wt. % of an aromatic amine started polyether with a molecular weight of 300 to 800 based on 70 to 100 wt. % of 1,2-propylene oxide and 0 to 30 wt. % of ethylene oxide2) 10 to 40 wt. % of a substantially sucrose started polyether with a molecular weight of 400 to 1,000 based on 70 to 100 wt. % of 1,2-propylene oxide and 0 to 30 wt. % of ethylene oxide3) 5 to 30 wt. % of a propylene glycol started polyether with a molecular weight of 500 to 1,500 based on 70 to 100 wt. % of 1,2-propylene oxide and 0 to 30 wt. % of ethylene oxide4) n-pentane and/or i-pentane as blowing agent5) water6) optional auxiliary agents and additives,wherein the sum of the wt.

Abstract: Rigid foams which possess urethane groups are prepared by reacting polyisocyanates with compounds which possess at least two active hydrogen atoms which are reactive towards isocyanate groups, in the presence of water and alkanes as blowing agent and solution promoters. The solution promoter used is a compound with a polar group.

Abstract: Rigid polyurethane foams are prepared by the reaction of1) polyisocyanates with2) compounds of a molecular weight of from 150 to 1500, having at least two hydrogen atoms active towards isocyanates and which one tertiary nitrogen atom in the molecule, in the presence of3) hydrofluoroalkanes as foaming agents as well as optionally in the presence of4) other auxiliary substances and additives known per se.

Abstract: The invention relates to a process for insulating pipes by applying a rigid polyurethane foam as an insulating layer and optionally an external top coating by the rotational casting process. The rigid polyurethane foam is obtained by a) an aromatic polyisocyanate, b) an organic polyhydroxyl compound, c) an aliphatic, cycloaliphatic or aromatic polyamine and/or polyimine having a molecular weight of from 32 to 1,000 as the cross linking agent in the presence d) a blowing agent, and optionally in the presence of e) known auxiliary substances and additives and in the presence of f) one or more compounds having a molecular weight of from about 166 to about 1,000 and being of the general formula ##STR1## wherein n represents an integer between 2 and 9, preferably 2 and 3,R.sup.1 signifies hydrogen, a C.sub.1 -C.sub.9 alkyl radical or a ##STR2## R.sup.2 signifies hydrogen, and R.sup.3 and R.sup.4 signify hydrogen or methyl.

Abstract: The present invention relates to hard polyurethane foams. These foams are produced by the reaction of 1) polyisocyanates, with 2) compounds having molecular weights of from 92 to 10,000 and having at least two hydrogen atoms which are reactive with isocyanate groups, in the presence of 3) hydrofluoroalkanes as foaming agents, and 4) solubilizers. Suitable solubilizers comprise one or more of ##STR1## wherein R.sup.1 and R.sup.2 signify C.sub.1 -C.sub.12 -alkyl or together C.sub.2 -C.sub.6 -alkylene and n signifies an integer from 0 to 6; ##STR2## wherein R.sup.1 to R.sup.3 signify C.sub.1 -C.sub.12 -alkyl which is optionally substituted by halogens, C.sub.5 -C.sub.10 -cycloalkyl or optionally substituted aryl; ##STR3## wherein R.sup.1 and R.sup.2 signify C.sub.1 -C.sub.16 -alkyl or C.sub.5 -C.sub.10 -cycloalkyl; and/or ##STR4## wherein R signifies C.sub.1 -C.sub.20 alkyl or C.sub.5 -C.sub.10 cycloalkyl.

Abstract: A process for insulating pipes comprises applying at least one layer of a polyisocyanurate plastic and then at least one layer of rigid polyurethane foam to a steel pipe. The foam is covered with an outer layer.

Abstract: Composite moldings of at least one layer of an ABS plastic and at least one layer of a thermoplastic polyurethane having a Shore D hardness of >50, a layer of coupling agent optionally being present between the ABS layer and the thermoplastic polyurethane layer.

Abstract: For insulating pipes by application of at least one insulating layer and at least one outer surface layer by rotational molding, a rigid polyurethane foam is used as the insulating layer while a solid polyurethane is used as the surface layer.

Abstract: Refrigeration units having internal parts containing a rigid polyurethane foam formed without the use of perhalogenated fluoro-chlorohydrocarbons are produced by applying a coating to the internal walls of the part in which back-foaming will take place, pouring a foam forming reaction mixture into the cavity of the part in which the internal walls have been coated and allowing the foam to form and set. The coating applied to the internal walls of the part in which back foaming is to be carried out is selected from one-component chemically cross-linking lacquers, two-component chemically cross-linking lacquers and lacquers based on aqueous polyurethane dispersions. The foam forming mixture generally includes a polyisocyanate, a polyisocyanate-reactive compound and a blowing agent. The blowing agent must include a partially halogenated hydrocarbon having at least one carbon-hydrogen bond and a boiling point in the range of from about -50.degree. to about 50.degree. C.