Abstract: The invention relates to a method for the preparation of di- and polyamines of the diphenylmethane series (MDA) from aniline and formaldehyde, care being taken during the start up that a sufficient excess of aniline with respect to formaldehyde is ensured, said excess amounting to at least 105% of the desired molar ratio of aniline to formaldehyde for the target recipe of the MDA to be produced.

Abstract: A polyether polyol composition comprising: a polyether polyol, a phosphoric acid compound selected from the group consisting of at least one of orthophosphoric acid, polyphosphoric acid, polymetaphosphoric acid, and partial esters thereof in an amount raning from 0.5 to 100 ppm based on the polyether polyol metals derived from a composite metal cyanide complex catalyst in an amount ranging from 1 to 30 ppm based on the polyether polyol; a method for producing this polyether polyol composition; and methods of making polyurethane or isocyanate group-terminated prepolymers.

Abstract: The invention relates to aliphatic, cycloaliphatic or (cyclo)aliphatic diisocyanates, in addition to a method for their production.

Abstract: A hardener composition for use as a component of a two component polyurethane coating composition, comprising a polyisocyanate, a catalyst for promoting reaction of the polyisocyanate with a reactive hydrogen compound, and one or more antioxidants selected from: a first antioxidant comprising one or more of sterically hindered phenol antioxidants and secondary aryl amine antioxidants, and a second antioxidant comprising one or more organophosphite antioxidant, exhibits improved color stability.

Abstract: The invention relates to a process for the production of di- and polyisocyanates of the diphenylmethane series and mixtures thereof, in which aniline and formaldehyde are reacted in the presence of an acid catalyst to form di- and polyamines of the diphenylmethane series; the di- and polyamines of the diphenylmethane series are phosgenated, optionally in the presence of a solvent, to obtain a crude di- and polyisocyanate; from the crude di- and polyisocyanate, at least one fraction containing at least 5 wt. % 3-ring and multi-ring MDI and at least one fraction containing at least 95 wt. % 2-ring MDI are separated by distillation, and the acidities of the fraction containing at least 5 wt. % 3-ring MDI and multi-ring MDI, and/or the fraction containing at least 95 wt. % 2-ring MDI are determined analytically; and an acidic compound is added to the fraction containing at least 5 wt. % 3-ring MDI and multi-ring MDI, and/or the fraction containing at least 95 wt.

Abstract: In a process for preparing mixtures of diphenylmethane diisocyanates and polyphenylpolymethylene polyisocyanates having a reduced content of chlorinated by-products and a reduced iodine color number by two-stage reaction of the corresponding mixtures of diphenylmethanediamines and polyphenylpolymethylenepolyamines with phosgene in the presence of at least one inert organic solvent at elevated temperature, separation of the excess phosgene and solvent after the phosgenation is complete and thermal treatment of the reaction product, the mass ratios of phosgene to hydrogen chloride in the residence time apparatus of the second stage of the phosgenation are at the same time 10-30:1 in the liquid phase and 1-10:1 in the gas phase.

Abstract: An isocyanate prepolymer composition having an extended potlife, without the addition of an excess amount of benzoyl chloride is disclosed. The isocyanate prepolymer composition includes an isocyanate prepolymer formed from the reaction of a polyhydroxyl compound with an excess of a polyisocyanate. The composition further includes included a plasticizer, and a phosphate ester. The phosphate ester has at least one acidic hydrogen and a pentavalent phosphorous atom. Preferably, the composition also includes very low levels of benzoyl chloride and an oil. Further disclosed is a polyisocyanate composition having an extended potlife comprising a polyisocyanate, a plasticizer and a phosphate ester having at least one acidic hydrogen and a pentavalent phosphorous atom.

Abstract: Mixtures of diphenylmethane diisocyanates and polyphenylpolymethylene polyisocyanates (raw MDI) having a reduced iodine color number and a reduced chlorine content are prepared by reacting the corresponding mixtures of diphenylmethanediamines and polyphenylpolymethylenepolyamines with phosgene in the presence of at least one inert organic solvent at elevated temperature, and then, after phosgenation is complete, incorporating into the reaction mixture, in the presence or absence of the phosgene, a mixture of water and at least one monohydric or polyhydric polyoxyalkylene alcohol, preferably having a functionality of from 2 to 3, and advantageously having a hydroxyl number of from 20 to 1800, in an effective amount which advantageously comprises from more than 0.01 to 0.3% by weight of water (i) and from 0.

Abstract: (Cyclo)aliphatic polyisocyanate compositions which have a long shelf life, are obtainable by phosgene-free methods, preferably by thermal cleavage of (cyclo)aliphatic polycarbamates, and, for stabilization, contain at least one primary stabilizer (2a), preferably a sterically hindered phenol and/or an aromatic amine, or at least one secondary stabilizer (2b), preferably an organic phosphite and/or a thioether, or at least one acidic stabilizer (2c), preferably a carboxylic acid, an acyl chloride, an inorganic acid, an inorganic acid chloride and/or a diester of phosphoric acid, or a stabilizer system comprising at least 2 of the stabilizers (2a) to (2c), a process for the preparation of the (cyclo)aliphatic polyisocyanate compositions and their preferred use for the preparation of isocyanurate-containing polyisocyanates.

Abstract: The present invention is directed to a process for the production of polymethylene polyphenyl polyisocyanates by phosgenating the corresponding polyamines in solution in an inert organic solvent, removing excess phosgene, and stripping the solvent. The improvement resides in adding at least 0.02 parts by weight of reducing agent per 150 parts by weight of polyamine to the polyamines at any time prior to the stripping step.

Abstract: A method for stabilizing an isocyanate compound by adding 10-5000 ppm of phenol to the isocyanate compound, and also an isocyanate composition so stabilized. In the isocyanate composition stabilized by the above method, coloring due to time-dependent changes and the occurrence of turbidity through self-polymerization are both suppressed so that it shows outstanding storage stability compared with a corresponding isocyanate composition containing a conventional stabilizer.

Abstract: The present invention relates to a process for the conditioning and/or purification of organic isocyanates bya) mixing organic isocyanates at 20.degree. to 150.degree. C. with 0.001 to 1 mole %, based on the isocyanate, of a silylated acid corresponding to the formulaX-[Si(CH.sub.3).sub.3 ].sub.nwhereinX represents the neutral acid residue obtained by removing the acidic hydrogen atoms from an n-basic acid having a pKa value of at most 3, with the exception of hydrohalic acids andn is an integer from 1 to 3, andb) optionally working up the resulting mixture by distillation after a residence time of at least 5 minutes.

Abstract: A method for preventing coloration of an aromatic isocyanate compound, which is characterized in that an organic phosphite ester of formula: ##STR1## wherein R.sup.1, R.sup.2, R.sup.3 and R.sup.4 are, the same or different, each a C.sub.4-20 hydrocarbon group, 2,6-di-tert.-butyl-4-methylphenol and triphenyl phosphite are added to the aromatic isocyanate compound.

Abstract: Mixtures of diphenylmethane diisocyanates and polyphenylpolymethylene polyisocyanates (crude MDI) of reduced iodine color number are prepared by reacting the corresponding mixtures of diphenylmethanediamines and polyphenylpolymethylenepolyamines with phosgene in the presence of at least one inert organic solvent at elevated temperature, at least one monohydric or polyhydric polyoxyalkylene alcohol, preferably having a functionality of from 2 to 3, and advantageously having a hydroxyl number of from 20 to 1800, or mixtures thereof in an effective amount, expediently in an amount of from 0.1 to 10% by weight, based on the weight of the crude MDI, being introduced into the reaction mixture when the phosgenation is complete, the phosgene and the inert organic solvent then being removed, up to 5% by weight, based on the weight of crude MDI, of at least one phenol-based antioxidant and/or aryl phosphite being added, if desired to the reaction product, and the reaction mixture being heated.

Abstract: The present invention relates to the use of nucleus-substituted 4-hydroxyphenyl propionic acid compounds for stabilizing organic polyisocyanates.

Abstract: The invention relates to elimination of discoloration in polyurethanes, particularly thermoplastic polyurethanes, by the addition to the reaction mixture from 0.