| 摘要 |
The invention relates to a method for producing rigid polyurethane foams from polyols, polyisocyanates, expansion agents and possibly foaming agents. Said method is characterized in that the rigid polyurethane foam is obtained by reacting A. a polyol component containing (1) 40 to 80 weight percent of a polyethylene oxide/propylene oxide polyether having a molar mass of 300 to 800 and based on sucrose or sorbitol, (2) 3 to 40 weight percent of a polyethylene oxide/propylene oxide polyether having of molar mass of 300 to 800 and based on an aromatic mono-, di- or polyamine, (3) 3 to 40 weight percent of a polyethylene oxide/propylene oxide polyether having a molar mass of 200 to 800 and based on an aliphatic mono-, di- or polyamine, (4) 3 to 40 weight percent of a linear polyethylene oxide/propylene oxide polyether having a molar mass of 500 to 1500, (5) possibly other compounds having a molar mass of 150 to 12500 g/Mol and at least two hydrogen atoms reactive to isocyanates, (6) catalysts, (7) water, (8) expansion agents from the group of alkanes, cycloalkanes, hydrofluorochlorohydrocarbons, hydrofluorohydrocarbons, and (9) possibly auxiliary agents and/or additives, with B. an organic and/or modified organic polyisocyanate having an NCO content of between 20 and 48 weight percent.
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