Abstract: Process for producing rigid polyurethane foams by reacting a) polyisocyanates with b) compounds having at least two hydrogen atoms which are reactive toward isocyanate groups in the presence of c) blowing agents, wherein the compounds having at least two hydrogen atoms which are reactive toward isocyanate groups comprise at least one polyether alcohol bi) which can be prepared by reacting aromatic amines with ethylene oxide and propylene oxide, with firstly propylene oxide and then ethylene oxide or a mixture of ethylene oxide and propylene oxide being added on in a first process step and the remaining amount of propylene oxide being added on in a second process step using a basic catalyst.

Abstract: Process for preparing polyether polyols having an end block of ethylene oxide by addition of alkylene oxides onto H-functional starter substances, in which A) a polyether polyol precursor is prepared by means of double metal cyanide (DMC) catalysis in a semicontinuous mode of operation in which previously prepared polyether polyol together with the DMC catalyst are placed in a reactor and H-functional starter substance and propylene oxide are added continuously, B) the polyether polyol precursor from stage A) is reacted with propylene oxide or an ethylene oxide/propylene oxide mixture in the presence of the DMC catalyst in a continuously operating reactor to give a polyether polyol intermediate, C) the intermediate from stage B) is mixed with an alkali metal hydroxide as catalyst and D) reacted with ethylene oxide in a continuously operating reactor to give the final product, E) the catalyst is separated off from the final product obtained in stage D).

Abstract: A process for the preparation of polyetherpolyols by reacting diols or polyols with ethylene oxide, propylene oxide, butylene oxide or a mixture thereof in the presence of a multimetal cyanide complex catalyst is proposed, the reaction being carried out in a stirred kettle reactor and the reaction mixture being circulated via an external heat exchanger by means of a pump.

Abstract: In a process for preparing polyether alcohols by catalytic addition of at least two alkylene oxides onto H-functional initiator substances, at least one multimetal cyanide compound is used as catalyst and the addition of the alkylene oxides onto the initiator substance includes incorporation of at least one oxyalkylene block during whose formation at least two alkylene oxides are metered in together and the ratio of the alkylene oxides to one another in the mixture is changed during the joint introduction.

Abstract: Polyetherols based on solid initiator substances and liquid, hydroxyl-containing coinitiators are prepared by a catalyzed addition reaction of alkylene oxides by a process in which the initiator combination contains diols carrying ethoxy structures, the ratio of the average number of hydroxyl groups per mole of initiator combination to the number of ethoxy structures in the polyetherol being from 1:0.2 to 1:1.8 and the ratio of the amounts by weight of the diols carrying ethoxy structures to the average molecular weight of the polyetherol being from 1:2 to 1:15. The polyetherols prepared by this process are used for the preparation of PUR, in particular, rigid PUR foams.

Abstract: A process for preparing double metal cyanide catalysts, comprising combining an aqueous solution of a metal salt of the formula M1m(X)n, with an aqueous solution of a cyanometallic acid of the formula HaM2(CN)b(A)c, where one or both aqueous solutions may comprises at least one water-miscible organic ligand selected from the group consisting of alcohols, aldehydes, ketones, ethers, polyethers, esters, ureas, amides, nitrites or sulfides, if desired, combining the aqueous suspension thus obtained with at least one water-miscible organic ligand selected from the above-mentioned group, which ligand may be identical to or different from any previously added ligand, and separating the resulting two-metal cyanide complex from the suspension.

Abstract: A process for treating polyether polyols prepared in a conventional manner by base-catalyzed reaction of H-functional initiator substances with alkylene oxides comprises a combination of a thermal-reactive step at a pH of less than 7 and a temperature above 60° C. and a thermal-distillative step in a countercurrent column using a purifying agent. The polyether polyols prepared according to the invention are used for producing low-fogging and low-odor PUR foams.

Abstract: In a process for producing flexible polyurethane foams by reactinga) organic and/or modified organic polyisocyanates withb) relatively high molecular weight compounds containing at least two reactive hydrogen atoms andc) if desired, low molecular weight chain extenders and/or cross linkersin the presence ofd) blowing agents,e) catalysts,f) flame retardants and, if desiredg) further auxiliaries and/or additives,the relatively high molecular weight compounds containing at least two reactive hydrogen atoms (b) comprise at least 10% by weight of polyether polyols which can be prepared by base-catalyzed reaction of lower alkylene oxides with OH-functional initiator substances and are subjected, during or after the molecular addition of alkylene oxide, to a combined thermal/distillative treatment at a water content of at most 0.1% by weight.The flexible PUR foam produced according to the present invention can be used in the automobile and furniture sectors and for producing flexible foam/textile composites.