Abstract: Isocyanates or isocyanate mixtures which are substantially free of color-imparting components are made by treating the isocyanate with hydrogen in the presence of a catalyst at a pressure of from about 3 to about 150 bar, a temperature of from about 100 to about 180.degree. C. for from about 15 minutes to about 4 hours. These isocyanates are particularly useful for the preparation of light-colored polyurethane rigid foams.

Abstract: Organic isocyanates are continuously prepared by reacting primary organic amines with phosgene in the presence of an inert, organic solvent, with the reaction mixture being circulated by means of a bubble column at a temperature of from 60.degree. to 100.degree. C. and with the ratio of the quantity of the circulated amine reaction products to the quantity of the amine supplied of from 100:1 to 5:1.

Abstract: Isocyanates or isocyanate mixtures which contain no appreciable amounts of color causing materials are produced by phosgenating the amine corresponding to the desired isocyanate and treating the isocyanate-containing phosgenation mixture with hydrogen in the presence of a supported catalyst. The supported catalyst is in a form such that its shortest dimension is from about 0.3 to about 3.0 mm. This catalyst has a BET surface of from about 0.5 to about 150 m.sup.2 /g. No alkali material can be present in the catalyst. These isocyanates are particularly useful for the production of light-colored foams.

Abstract: Polyaromatic polyisocyanates are modified by reaction with 0.1 to 10 weight %, preferably 2 to 7 weight % (based on polyisocyanate) of a polyether alcohol of molecular weight 206 to 948, obtainable by the reaction of alkylene oxides with C.sub.6 -C.sub.30, preferably C.sub.8 -C.sub.20, hydrocarbons containing 1 to 3 active H atoms, and are used for the production of rigid polyurethane foamed materials.

Abstract: An isocyanate terminated prepolymer based upon diphenylmethane isocyanates. This prepolymer is the reaction product of a diphenylmethane isocyanate mixture having from about 75 to about 95 wt % binuclear isomers and from about 5 to about 25 wt % polymeric isocyanate with a polyether polyol. The binuclear isomer content is generally from about 15 to about 40 wt % 2,4'-isomer and from about 2 to about 10 wt % 2,2'-isomer. The polyether polyol has a functionality of from about 3 to about 8, an OH number of from about 350 to about 1000 mg KOH/g and a molecular weight of from about 150 to about 1000. These prepolymers are particularly useful as starting materials for the production of light-colored, dimensionally stable rigid polyurethane foams.

Abstract: Polyaromatic polyisocyanates are modified by reaction with 0.1 to 10 weight %, preferably 2 to 7 weight % (based on polyisocyanate) of a polyether alcohol of molecular weight 206 to 948, obtainable by the reaction of alkylene oxides with C.sub.6 -C.sub.30, preferably C.sub.8 -C.sub.20, hydrocarbons containing 1 to 3 active H atoms, and are used for the production of rigid polyurethane foamed materials.

Abstract: This invention relates to novel urethane-modified polyisocyanate mixtures of the diphenylmethane series prepared by a process comprising reacting polyisocyanates or polyisocyanate mixtures of the diphenylmethane series with certain monohydric and/or polyhydric alcohols and, optionally, subsequently mixing the initially modified products with polyisocyanates or polyisocyanate mixtures of the diphenylmethane series that have not been modified with urethane groups. This invention further relates to the use of the polyisocyanate mixtures in the preparation of polyurethane foams.

Abstract: The instant invention is directed to a process for the solvent-free production of solid polyurethane moldings wherein the polyisocyanate used is a polyisocyanate mixture containing from 10 to 80% by weight of 2,4'-diisocyanatodiphenylmethane.

Abstract: The present invention relates to a process for the reinforcement of geological formations and loose rock and earth masses by introducing, into the cavities of the geological formations or rock or earth masses which are required to be reinforced, reaction mixtures based on organic polyhydroxyl compounds and organic polyisocyanates which react to form polyurethanes, which process is characterized in that the polyisocyanate component used is a polyisocyanate mixture containing from about 10 to 80%, by weight, of 2,4'-diisocyanato-diphenylmethane. The present invention also relates to a two-chamber cartridge suitable for carrying out the process according to the present invention.