Abstract: The invention relates to a 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 a mixture of b1) a polyether alcohol which has a functionality of 4 and a hydroxyl number of from 380 to 450 mg KOH/g and a viscosity of greater than 12 000 mPa·s and can be prepared by addition of ethylene oxide and/or propylene oxide onto TDA, b2) a polyether alcohol which has a functionality of from 5 to 7.

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: The invention relates to a process for preparing polyether alcohols by catalytic addition of alkylene oxides onto a starter substance mixture comprising water-soluble H-functional starter substances which are solid at room temperature, alcohols which are liquid at the reaction temperature and water using alkali metal hydroxides and/or alkaline earth metal hydroxides as catalysts, wherein the amount of water is from 1.0 to 6.0% by weight, based on the weight of the starter substance mixture, and the starter substance mixture comprises no amine constituents.

Abstract: Process for the preparation of polyether alcohols, wherein the alkoxylation is carried out in the presence of sheet silicates.

Abstract: The invention relates to a 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 a mixture of b1) a polyether alcohol which has a functionality of 4 and a hydroxyl number of from 380 to 450 mg KOH/g and a viscosity of greater than 12 000 mPa·s and can be prepared by addition of ethylene oxide and/or propylene oxide onto TDA, b2) a polyether alcohol which has a functionality of from 5 to 7.

Abstract: Polyester-polyether block copolymers can be prepared by catalytic addition of alkylene oxides onto H-functional initiator substances, using polyester alcohols as H-functional initiator substances and multimetal cyanide compounds as catalysts.

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: 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 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 ethoxy structures to the average molecular weight of the polyetherol being from 1:2 to 1:15.

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: Polyurethanes having improved curing are prepared by reactinga) organic and/or modified organic diisocyanates and/or polyisocyanates withb) polyether polyols based on aromatic amines, able to be prepared by reacting specific amine combinations and, if desired, further coinitiators in a stage wise molecular addition of alkylene oxide, and also, if desired, further relatively high molecular weight compounds containing at least two reactive hydrogen atoms and, if desired,c) low molecular weight chain extenders and/or crosslinkers in the presence ofd) blowing agents,e) catalysts and, if desired,f) further auxiliaries and/or additives,wherein the specific amine combination used is a mixture of amines of the diphenylmethane series consisting of from 5 to 20% by weight of 4-ring amine, from 15 to 30% by weight of 3-ring amine, from 20 to 35% by weight of amines having more than 4 rings and from 25 to 50% by weight of 2-ring amine, wherein the proportions add up to 100% by weight, in combination with further aromatic

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.

Abstract: In a process for preparing polyether polyols containing aromatics by molecular addition of alkylene oxides to H-functional initiators at from 70.degree. C. to 135.degree. C. and pressures of from 0.1 MPa to 1.0 MPa, the alkoxylation is carried out using at least one initiator comprising at least 95% by weight of 2,3 and 3,4 isomers of tolylenediamine, from 0.5 to 4% by weight of 2,4 and 2,6 isomers of tolylenediamine and from 0.1 to 1.5% by weight of more volatile fractions from tolylenediamine production. The polyether polyols prepared by this process can be used as component of a polyol mixture for producing rigid polyurethane foams.