Abstract: In a process for producing polyurethanes by reacting at least one polyisocyanate with at least one compound containing at least two hydrogen atoms which are reactive toward isocyanate groups, the compound having at least two active hydrogen atoms which is used is at least one polyether alcohol prepared by addition of alkylene oxides onto H-functional initiator substances by means of multimetal cyanide catalysis and the reaction is carried out in the presence of at least one metal salt.

Abstract: Catalysts contain, as structural units, at least one tertiary amino group and at least one group which, after its decomposition, is capable of complexing or protonating the tertiary amino group.

Abstract: Catalysts and processes for preparing polyisocyanates containing isocyanurate groups, and their use, wherein the catalysts are represented by the following formula (1): [Hl?Xm?Fn?]p·[R(4?q)Si(NR1R2)q]r??(I), wherein n=m+l with 1?m/n>0, and l?0, p>0 and r>0, and the ratio p/r is any value, q=1 or 2, and R, R1, R2 and X are as defined.

Abstract: A process for preparing an emulsion is disclosed. The process entails mixing an aqueous mineral acid that contains phosphorous in an organic solvent, the mixing being continuous and with the degree of intensity sufficient to form a homogeneous emulsion. The emulsion prepared by the process is useful in the process of preparing polycarbonate by the interfacial process. Accordingly the washed organic polycarbonate that has been washed without the use of a phosphorous containing mineral acid solution is mixed with the novel emulsion. The resulting polycarbonate is characterized by its improved thermal stability.

Abstract: The present invention has an object to provide a flame-retardant epoxy resin composition excellent in heat resistance and moisture resistance. A flame-retardant epoxy resin composition relating to the present invention contains an epoxy resin (A), a phosphazene compound (B), an epoxy hardener (C) and an inorganic filler (D), wherein the phosphazene compound (B) and the epoxy hardener (C) are included in the range of 0.

Abstract: The invention relates to polyisocyanates which contain uretdione groups, have a particularly low monomer content and are stable towards redissociation and also to their use.

Abstract: The present invention relates to an improved process for the continuous preparation of polyisocyanates with a biuret structure comprising the steps of continuously reacting excess amounts of organic diisocyanates having exclusively aliphatically and/or cycloaliphatically bound isocyanate groups with organic diamines having exclusively aliphatically and/or cycloaliphatically bound primary amino groups at temperatures above 170° C. and adding acid before or during the reaction.

Abstract: A method for the production of polyurethane products using very low unsaturation polyether polyols prepared in the presence of aluminum phosphonate catalysts is disclosed. Reaction products of the process include various polyurethane products including foams, coatings, adhesives, sealants and elastomers. The aluminum phosphonate catalyst preferably has a general structure of RPO-(OAlR′R″)2, wherein O represents oxygen, P represents pentavalent phosphorous, Al represents aluminum, R comprises a hydrogen, an alkyl group, or an aryl group, and R′ and R″ independently comprise a halide, an alkyl group, an alkoxy group, an aryl group, or an aryloxy group.

Abstract: A treatment agent for elastic polyurethane fibers comprising a dispersion in which a higher fatty acid magnesium salt is colloidally dispersed in a silicone mixture consisting of a silicone oil with a viscosity of 5×10−6−50×10−6 m2/S at 25° C. as a dispersion medium and a dispersant mainly comprising a modified silicone at a ratio by weight of the dispersion medium/the dispersant=100/0.5-100/4.5, wherein the amount of the higher fatty acid magnesium salt is 1 to 10 parts by weight per 100 parts by weight of the silicone oil.

Abstract: The invention concerns optically active polymers, obtainable by polymerizing chiral diphosphine having a C2 axis of symmetry, excluding all other symmetry element, with one or several polymerizable monomers, said chiral diphosphine consisting of a chiral body bearing two identical functional groups capable of reacting with said polymerizable monomers.

Abstract: The invention relates to novel ionic liquids, to a process for their preparation, and to their use as solvents or catalysts for chemical reactions, especially as catalysts for the oligomerisation of isocyanates.

Abstract: The invention pertains to a new composition comprising at least one isocyanate-functional compound comprising at least two isocyanate groups, at least one isocyanate-reactive compound comprising at least two isocyanate-reactive groups selected from mercapto groups, hydroxyl groups, and mixtures thereof, and a co-catalyst comprising a phosphine and a Michael acceptor. The invention further relates to a coating composition comprising the above composition, a method of coating a substrate comprising coating the substrate with the above composition, a substrate coated with that composition, the use of the above composition in the (re)finishing of large vehicles and refinishing of cars, and an adhesive comprising the above composition.

Abstract: A method for the production of polyurethane products using very low unsaturation polyether polyols prepared in the presence of aluminum phosphonate catalysts is disclosed. Reaction products of the process include various polyurethane products including foams, coatings, adhesives, sealants and elastomers. The aluminum phosphonate catalyst preferably has a general structure of RPO-(OAlR′R″)2, wherein O represents oxygen, P represents pentavalent phosphorous, Al represents aluminum, R comprises a hydrogen, an alkyl group, or an aryl group, and R′ and R″ independently comprise a halide, an alkyl group, an alkoxy group, an aryl group, or an aryloxy group.

Abstract: The solvent-free two-component adhesive composition of the present invention comprises a polyol component (A) and a polyisocyanate component (B), and the viscosity of the mixture at 80° C. immediately after the point of time the components (A) and (B) are mixed together is 900 mPa·s or higher. The component (A) may be a polyol having a number average molecular weight of 800 or larger, or a mixture thereof, and the viscosity of the component (B) at 25° C. may be 20,000 mPa·s or higher. The composition may be used for laminating metal foil of 5 to 15 m thickness with a plastic film. By using the composition of the present invention, the occurrence of blocking due to the seepage of the adhesive from metal foil is prevented. The present invention includes a process of lamination using the same.

Abstract: A light-colored thermoplastic molding composition comprising a polyurethane elastomer is disclosed. The polyurethane which is the reaction product of at least one polyol, at least one organic diisocyanate and at least one polyol chain extender contains one or more pentaerythritol diphosphites color stabilizers conforming to a specific formula exhibits improved color stability and improved processability. The process for preparation entails introducing the stabilizer before the reaction has been completed.

Abstract: A modified carbodiimide resin obtainable by reacting a carbodiimide resin comprising a repeating unit represented by the general formula: —(NCN—R1)- wherein R1 represents a divalent organic group, with an aromatic diamine represented by the general formula: H2N—R2—NH2 wherein R2 represents a divalent organic group having a benzene ring, and a thermosetting resin composition comprising the modified carbodiimide resin and an epoxy resin.

Abstract: A continuous process for the production of thermoplastically processable polyurethane elastomer is disclosed. The process comprise adding acid H compounds in an amount calculated to control and render constant the melt viscosity of the product. The inventive elastomer has constant melt flow behavior and high thermal stability.

Abstract: The present invention relates to an improved process for the continuous preparation of polyisocyanates with a biuret structure comprising the steps of continuously reacting excess amounts of organic diisocyanates having exclusively aliphatically and/or cycloaliphatically bound isocyanate groups with organic diamines having exclusively aliphatically and/or cycloaliphatically bound primary amino groups at temperatures above 170° C. and adding acid before or during the reaction.

Abstract: The invention pertains to a new composition comprising at least one isocyanate-functional compound comprising at least two isocyanate groups, at least one isocyanate-reactive compound comprising at least two isocyanate-reactive groups selected from mercapto groups, hydroxyl groups, and mixtures thereof, and a co-catalyst comprising a phosphine and a Michael acceptor. The invention further relates to a coating composition comprising the above composition, a method of coating a substrate comprising coating the substrate with the above composition, a substrate coated with that composition, the use of the above composition in the (re)finishing of large vehicles and refinishing of cars, and an adhesive comprising the above composition.

Abstract: The present invention relates to a composition based on isocyanate(s), advantageously not completely masked. This composition is defined in that it comprises a compound containing an anionic functional group and a polyethylene glycol chain fragment of at least 5, advantageously of at least 7 ethyleneoxy units. Application to organic synthesis.

Abstract: An energy sensitive composition comprising a monomeric organometallic complex essentially free of nucleophilic groups and which, upon exposure to energy, bonds to basic reactive sites on a substrate via the metal center, leaving the polymerizable group of the complex unreacted and unrestricted; an energy sensitive composition at least one energy sensitive organometallic group is incorporated in or appended to the backbone of a polymer, such that the resulting coordinatively unsaturated organometallic group or groups bond to basic reactive sites on a substrate, thus forming permanent bonds, and further, the adherent compositions are useful in applications such as adhesion of polymers to substrates, protective coatings, printing plates, durable release coatings, primers, binders, and paints.

Abstract: A one-pack type moisture curable urethane composition comprising a urethane prepolymer and an amine catalyst, wherein 0.002 to 50 parts by weight, based upon 100 parts by weight of the urethane prepolymer, of phosphonic ester compounds, phosphonous ester compounds, phosphinous ester compounds or phosphine compounds or any mixture thereof is compounded to give the urethane composition having an improved storage stability, without decreasing the catalyst activity even when an amine catalyst having a high catalytic activity dimethylamino group structure etc. is used.

Abstract: Method for the treatment of mineral fillers using organic phosphate treatment agents. Treated mineral fillers obtained by said method and suspension of these treated mineral fillers in polyols. Use of these suspensions in the manufacture of flexible, semirigid, or rigid polyurethane foams used for the manufacture of molded or nonmolded objects.

Abstract: A hydrophilic dicyclohexylmethanecarbodiimide represented by the formula (1): wherein n is an integer of 1 to 10 and R.sup.1 is a residue of a mixture of organic compounds of different hydrophilicities each having at least one hydroxyl group capable of reacting with an isocyanate group. The hydrophilic dicyclohexylmethanecarbodiimide is improved in reactivity and storage stability, and is thereby easy to handle as a crosslinking agent for hydrophilic resins.

Abstract: The present invention relates to a process for the production of trimerized polyisocyanates containing at least 30 mole % of iminooxadiazinedione groups (asymmetric trimers) in the trimer mixture by catalytically trimerizing a starting isocyanate selected from organic di- or polyisocyanates having a number average molecular weight of 140 to 600 and containing aliphatically, cycloaliphatically and/or araliphatically bound isocyanate groups in the presence of quaternary ammonium and phosphonium fluoride trimerization catalysts corresponding to the formulaR.sub.4 E.sup.+ F.sup.- (I),whereinE represents N or P andR represents identical or different, optionally branched, aliphatic, aromatic and/or araliphatic C.sub.1 -C.sub.

Abstract: The present invention relates to an ablative fire resistant hydrophilic polyurea foam made from low molecular weight polyols capped with an isocyanate, with the polyol mixture including a fire retardant polyol that preferably includes carborane disilanol, with the fire retardant polyol containing the carborane disilanol imparting superior fire retardancy characteristics. The present invention also relates to a prepolymer for forming the polyurea foam and the present invention especially relates to the use of a carborane disilanol fire retardant polyol. The present invention also relates to a method for forming the polyurea foam and the prepolymer.

Abstract: The present invention relates to a process for the preparation of trimerized polyisocyanates that contain at least 30 mole % of iminooxadiazinedione groups (asymmetric trimers) in the trimer mixture, by catalytically trimerizing a starting isocyanate selected from organic di- or polyisocyanates having a number average molecular weight of 140 to 600 and containing aliphatically, cycloaliphatically and/or araliphatically bound isocyanate groups in the presence of a quaternary phosphonium polyfluoride trimerization catalyst corresponding to the formulaR.sub.4 P.sup.+ F.sup.- n(HF)whereinR represents identical or different, optionally branched aliphatic, aromatic and/or araliphatic C.sub.1 -C.sub.20 groups, or two or more R groups may also form, with one another and with the phosphorus atom, saturated or unsaturated rings andn has a value of 0.1 to 20.

Abstract: There are provided a polycarbodiimide copolymer having a main structure represented by the following formula (1): ##STR1## wherein R.sub.1 is an isocyanate residue; R.sub.2 is a polyfunctional liquid rubber residue; X is a urethane bond, an amide bond or a urea bond; p is an integer of 5 to 50; q is an integer of 1 to 5; and r is 0 or 1; and a process for producing the above polycarbodiimide copolymer, which comprises reacting a polyfunctional liquid rubber with an organic diisocyanate in excess of the rubber and then subjecting the diisocyanate components in the reaction system to carbodiimization using a carbodiimidization catalyst. The polycarbodiimide copolymer alleviates the problems of the prior art, has the excellent heat resistance inherently possessed by polycarbodiimide resins, is improved, as compared with conventional polycarbodiimide resins, in thermoformability under heating and pressure when made into a solid such as a powder or granules, and causes no blistering under heating.

Abstract: A flexible polyurethane foam prepared by reacting polyisocyanate with polyol and/or polymer polyol containing dispersed polymer microparticles obtained by polymerizing an unsaturated compound, water, catalyst, surfactant and, when needed, crosslinking agent and other auxiliary agents, wherein a portion or the whole of the polyol and/or the polymer polyol is prepared in the presence of a compound having a nitrogen-phosphorus double bond as a catalyst, have excellent wet compression set, fatigue by constant-load pounding and dynamic durability.

Abstract: The present invention relates to a process for the production of polyisocyanates containing uretdione groups bya) oligomerizing a portion of the isocyanate groups of diisocyanates having aliphatically and/or cycloaliphatically bound isocyanate groups in the presence of catalysts or catalyst systems which accelerate the dimerization of isocyanate groups and in the presence of trisubstituted phosphite stabilizers corresponding to formula (I) ##STR1## b) optionally termination of the oligomerization reaction at a degree of oligomerization of 10 to 60% by adding a catalyst poison andc) optionally removing unreacted diisocyanate by extraction or thin-layer distillation.The present invention also relates to the use of the resulting uretdione polyisocyanates as a starting component for polyurethane plastics, particularly as an isocyanate component for the production of uretdione hardeners for powder coating compositions.

Abstract: Medical article of manufacture comprising compositions, comprising: at least one polyisocyanate, preferably a non-aromatic polyisocyanate, in the monomer or prepolymer state; at least one polypol; and at least one organic compound comprising one or more phosphite functional groups, in the proportion of at least 1% by weight with respect to the total weight of the polyol or polyols, this organic compound being, in addition, non-aromatic and the carrier of at least one free hydroxyl group capable of reacting with an isocyanato group; and, if appropriate, at least one catalyst of the polymerization reaction of a polyisocyanate and of a polyol.

Abstract: Storage-stable/clear solutions of linear aromatic poly(imideamides), well adopted for forming high luminance films and varnishes, comprise (a) an anhydrous .gamma.-butyrolactone solvent phase, such .gamma.-butyrolactone solvent phase (a) having from 5% to 40% by weight of a linear aromatic poly(imideamide) (b) dissolved therein, such linear aromatic poly(imideamide) (b) comprising the copolymerizate of (i) 2,4-diisocyanatotoluene, 2,6-diisocyanatotoluene, or mixture thereof, with (ii) a tricarboxylic acid monoanhydride, e.g., trimellitic acid monoanhydride, optionally, (iii) an aromatic dicarboxylic acid, e.g., terephthalic or isophthalic acid, and (iv) a monocarboxylic acid or dicarboxylic acid monoanhydride chain limiting agent, e.g., benzoic acid or phthalic anhydride.

Abstract: Internal mold release compositions for molding polyurethane and polythiourethane is disclosed herein. The composition includes a mixture of: (a) a mono C.sub.2 -C.sub.6 alkyl phosphate; (b) a di C.sub.2 -C.sub.6 alkyl phosphate, wherein the alkyl groups of the di-alkyl phosphate may be the same or different, and wherein the alkyl groups of the mono- and di-alkyl phosphate may be the same or different; and (c) a C.sub.7 -C.sub.18 mono- and/or di-alkyl phosphate. Also disclosed is a polymerizable composition which includes (a) one or more monomers containing two or more isocyanate groups; (b) one or more monomers containing two or more functional groups selected from a thiol group and a hydroxyl group; (c) a mixture of a mono- C.sub.2 -C.sub.6 alkyl phosphate and a di- C.sub.2 -C.sub.6 alkyl phosphate, wherein the alkyl groups of the di-alkyl phosphate may be the same or different and wherein the alkyl groups of the mono- and di-alkyl phosphate mixture may be the same or different, wherein the mono- C.sub.2 -C.

Abstract: Flame-resistantly formulated, flowable, latently reactive, phenolically curable epoxy-resin moulding compounds for the encapsulation of electronic components containing the following components:an epoxy-resin component obtained from a solvent-free reaction resin mixture of polyepoxy resin and polyisocyanate resin having a molar ratio of the epoxy groups to the isocyanate groups of 1.1 to 4 at a reaction temperature of up to 220.degree. C. in the presence of a reaction accelerator in a concentration of 0.5 to 2.5% and using triphenylphosphine oxide in a concentration of 0.05 to 10%, relative in each case to the reaction resin mixture,a hardener component containing at least two phenolic hydroxyl groups per molecule,inorganic filler,and standard additives.

Abstract: A laminate comprising a layer formed by melt molding a thermoplastic polyurethane and a fibrous base layer, a film or sheet melt molded from the thermoplastic polyurethane, and a thermoplastic polyurethane composition comprising the thermoplastic polyurethane and tin compound in an amount of 0.3 to 15 ppm (in terms of tin atom) based on the thermoplastic polyurethane; the thermoplastic polyurethane being a thermoplastic polyurethane obtained from a polymeric diol (a) having a number average molecular weight of 1,500 to 4,000, an organic diisocyanate (b) and a chain extender (c) and having an inherent viscosity of at least 0.9 dl/g and a retention of long-chain hard segments when heat melted of at least 80%, the polymeric diol (a) having a crystallization enthalpy (.DELTA.H) of not more than 70 J/g and having low molecular diol units comprising at least 30 mole % of 1,9-nonanediol units.

Abstract: An energy-polymerizable composition derived from ingredients comprising: a cyanate ester monomer or oligomer comprising an organic radical bonded through aromatic carbon atoms to at least two --OCN groups; a low molecular weight polyalkylene glycol; and an organometallic compound in which at least one carbon atom of an organic group is bonded to a metal atom. The composition can be cured by at least one of thermal energy, radiation, and accelerated particles, to produce a cured, homogeneous composition.

Abstract: A robust polyurethane liner is disclosed for solid propellant rocket motors which is insensitive to large variations in stoichiometry, exhibits increased cohesive strength and, when used in combination with a unique two coat (wet coat) liner process described below, modifies the ballistic properties of the adjacent interfacial propellant layer. The liner compositions include a polymeric binder having a plurality of reactive hydroxyl functional groups and a curing agent having a plurality of reactive isocyanate functional groups. The quantity of binder and curing agent is selected such that the NCO/OH ratio is in the range from 1.5 to 4.5. Diisocyanate curing agents are particularly useful. A bonding agent, such as a polyfunctional aziridine compound, is typically present in the liner composition in an amount ranging from about 3% to about 5%, by weight. An oligomer catalyst is included in the liner composition in an amount ranging from about 15% to about 50%, by weight. Diammonium phosphate ((NH.sub.4).sub.

Abstract: An energy-polymerizable composition derived from ingredients comprising: a cyanate ester monomer or oligomer comprising an organic radical bonded through aromatic carbon atoms to at least two --OCN groups; a low molecular weight polyalkylene glycol; and an organometallic compound in which at least one carbon atom of an organic group is bonded to a metal atom. The composition can be cured by at least one of thermal energy, radiation, and accelerated particles, to produce a cured, homogeneous composition.

Abstract: This invention relates to solid elastomeric polyurethanes prepared by reacting, in an open mold at an isocyanate index of 80 to 120,(a) an isocyanate prepolymer having an isocyanate content of 3 to 15% by weight and a number average molecular weight of 550 to 20,000 prepared by the reaction of(1) organic polyisocyanates having 2 to 3 NCO groups, and(2) isocyanate-reactive polyester polyols having two to three isocyanate-reactive hydroxyl groups and a number average molecular weight of 400 to 10,000 and prepared in the presence of an esterification catalyst, and optionally containing other isocyanate-reactive compounds,wherein the equivalent ratio of isocyanate groups to isocyanate-reactive groups is 1.2:1 to 34:1;(b) a diol chain extender, optionally in admixture with a crosslinker and/or an amino-containing chain extender and/or crosslinker;(c) 0.001 to 10% by weight, based on the weight of the isocyanate prepolymer, of a catalyst; and(d) 0.

Abstract: A composition for a urethane-base plastic lens, comprising:(a) at least one ester compound selected from the group consisting of isocyanate compounds, isothiocyanate compounds and isocyanato-containing isothiocyanate compounds,(b) at least one active hydrogen compound selected from the group consisting of hydroxyl compounds, mercapto compounds and mercapto-containing hydroxyl compounds,(c) a tertiary amine, and(d) a Lewis acid;a plastic lens obtained by heating and curing the composition, and a process for the production of the plastic lens. The composition has a long pot life and can produce an optically uniform plastic lens in a short time.

Abstract: A thermoplastic polyurethane composition comprises a thermoplastic polyurethane and a tin compound. The tin compound is contained in an amount of 0.3 to 15 ppm as converted into tin atom based on the thermoplastic polyurethane. The thermoplastic polyurethane composition has a retention ratio of long-chain hard segments when melt treated at 220.degree. C. for 60 minutes of at least 85%. The thermoplastic polyurethane composition also has a retention ratio of inherent viscosity when melt treated at 220.degree. C. for 6 minutes and then melt extruded and, thereafter, allowed to stand at 20.degree. C., 60% RH (relative humidity) for 24 hours of at least 85%. The thermoplastic polyurethane composition has excellent mold-ability and gives molded products being excellent in tensile strength and elongation, heat resistance, compression set, resistance to hydrolysis and like properties, and are hence useful as a raw material for various items.

Abstract: A rigid thermoplastic polyurethane with improved melt strength can be prepared by deactivating the catalyst for the polymer subsequent to the onset of urethane bond formation. Catalyst deactivation is accomplished either with a latent deactivator for the catalyst, or an active deactivator. The further addition of a crosslinker to the reaction mixture can provide an even greater improvement of melt strength.

Abstract: The invention relates to novel polysilicic acid/polyisocyanate basic materials, binding materials and foams with improved mechanical properties as well as a higher resistance against heat and chemicals. It is characteristic of the new base materials that they are built up (composed) of______________________________________ 100 parts by mass of a polyisocyanate, 50-400 parts by mass of a polysilicic acid component, 0.5-70 parts by mass of phosphoric acid triesters and/or salts of phosphoric acid mono- and/or diesters formed with amines and/or alkaline metals, and optionally 0-5 parts by mass of a catalysts containing a tertiary amino group, 0-50 parts by mass of a reactive diluent, 0-10 parts by mass of tenside(s) ______________________________________as well as 0-400% by mass of fillers and optionally other auxiliaries, calculated for the total mass (=100%) of the components listed above.

Abstract: A composition comprising a phosphorus containing acid and an ester of a phosphorus containing acid useful for imparting improved physical and chemical properties to polymers containing polyesters, copolyester carbonates, polycarbonates, and mixtures thereof, a method of treating said polymers with said composition, and articles of manufacture comprising said polymers and said composition.

Abstract: Disclosed are certain aromatic polycarbodiimides. Also disclosed is the use of an aromatic polycarbodiimide containing only aromatic carbodiimide groups as a cross-linker for a coating binder polymer bearing carboxyl groups.

Abstract: The invention describes anisotropic polymers of diepoxide A having the formula (I) ##STR1## and anisotropic polymers of diisocyanate B having the formulas (II) to (VII) ##STR2## where as defined in the specification.

Abstract: A member for electrically cooperating with a conductive support surface to attract charged toner particles from the surface towards the member is disclosed. The member comprises a conductive substrate capable of supporting a uniform bias potential thereon and at least one coating comprising a resilient elastomeric polyurethane.

Abstract: A linear segmented polyurethaneurea having a degree of branching (Nb) of 3 or less and obtained by chain-extending a prepolymer with an organic diamine in an organic solvent comprising dimethylformamide or dimethylacetamide, wherein the prepolymer has an isocyanate group at the both ends thereof and comprises a stoichiometrically excessive amount of a diisocyanate component selected from 4,4'-diphenylmethane diisocyanate, 2,4-toluene diisocyanate and 1,4-phenylene diisocyanate and a diol component having a number average molecular weight of 500 to 6000.

Abstract: A polyurethane adhesive composition prepared by incorporating phosphorus oxy acid or a derivative thereof, an amine compound and an epoxy resin into an organic polyisocyanate and an organic polyol.The polyurethane adhesive composition is employed in the manufacture of composite films by lamination of various plastic films, metal foils and so forth. The composition is excellent in adhesive properties, acid resistance and hot water resistance.

Abstract: Polyols are conditioned and stabilized by mixing them at 0 to 150.degree. C. with from about 0.0001 to about 1% by weight, based on the quantity of polyol, of a silylated acid corresponding to the formula:X--[Si(CH.sub.3).sub.3 ].sub.nin whichX represents a neutral acid residue obtained by removal of the acidic hydrogen atoms from an n-basic acid having a maximum pKa value of 3, provided that the n-basic acid is not a hydrohalic acid andn represents an integer of from 1 to 3.The resultant polyol is characterized by good color and activity properties. The stabilized polyols are particularly useful in the production of polyurethanes, particularly polyurethane foams.