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: A fraction of diisocyanates of the diphenylmethane series containing at least 95 wt. % binuclear methylenediphenyl diisocyanate is obtained by a) reacting aniline and formaldehyde in the presence of an acid catalyst to produce diamines and polyamines of the diphenylmethane series containing binuclear methylenediphenyl diamine, b) phosgenating the diamines and polyamines produced in a), optionally in the presence of a solvent, to produce a crude diisocyanate and polyisocyanate, and c) separating a fraction containing at least 95 wt. % binuclear methylenediphenyl diisocyanate with a 4,4?-MDI content of over 60 wt. %, a 2,4?-MDI content of 4 to 35 wt. % and a 2,2?-MDI content of 0.01 to 10 wt. %, relative to the mass of the fraction, and a maximum of 20 ppm phenyl isocyanate and optionally a maximum of 50 ppm solvent from the crude diisocyanate and polyisocyanate produced in b) in a single distillation step with optional upstream and/or downstream separation of low-boiling components.

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: A fraction of diisocyanates of the diphenylmethane series containing at least 95 wt. % binuclear methylenediphenyl diisocyanate is obtained by a) reacting aniline and formaldehyde in the presence of an acid catalyst to produce diamines and polyamines of the diphenylmethane series containing binuclear methylenediphenyl diamine, b) phosgenating the diamines and polyamines produced in a), optionally in the presence of a solvent, to produce a crude diisocyanate and polyisocyanate, and c) separating a fraction containing at least 95 wt. % binuclear methylenediphenyl diisocyanate with a 4,4?-MDI content of over 60 wt. %, a 2,4?-MDI content of 4 to 35 wt. % and a 2,2?-MDI content of 0.01 to 10 wt. %, relative to the mass of the fraction, and a maximum of 20 ppm phenyl isocyanate and optionally a maximum of 50 ppm solvent from the crude diisocyanate and polyisocyanate produced in b) in a single distillation step with optional upstream and/or downstream separation of low-boiling components.

Abstract: Hydroxyfunctional compounds suitable for use in the polyisocyanate polyaddition process are obtained from polyurethane and/or polyurethane polyurea waste by decomposition with an alcohol and subsequent reaction of the alcoholysis products to reduce their content of low molecular weight, sterically unhindered aromatic amines. In this process, polyurethane and/or polyurethane polyurea waste is first treated with a low molecular weight diol or polyol at a temperature of from about 160 to 260.degree. C. The resultant alcoholysis product may then either be further heated at a temperature lower than that used in the first step within the ranger of from about 50 to 180.degree. C. or reacted with a dialkyl carbonate and/or 1,3-dicarbonyl compound.

Abstract: Tertiary amines having carbonate and urethane groups and optionally hydroxyl groups are produced by reacting a) a polyhydric alcohol and b) a primary-tertiary diamine with c) a carbonic acid derivative selected from the group consisting of optionally cyclic carbonates, urea, phosgene and bis-chlorocarbonates of alcohols of the same type as those used as component a). This reaction may be carried out in one or two steps. The tertiary amines produced by this process are useful as catalysts, which may optionally be incorporated into an isocyanate-reactive material, in the isocyanate addition reaction for the production of polyurethane plastics. These tertiary amines are particularly useful for the production of foam backed plastic films.

Abstract: A process is described for producing polyurethane moldings by the reaction of compounds of molecular weight 400 to 10,000 which contain at least 2 hydrogen atoms capable of reacting with isocyanates, and optionally chain extenders of molecular weight 32 to 399, with polyisocyanates, optionally in the presence of foaming agents, auxiliary materials and additives, in which defined carbamates are used as activators. The polyurethanes obtained by this process are particularly low in emissions, i.e. are stable in relation to diffusion and exhibit low fogging, and are thus particularly suitable for the production of composite bodies comprising a polyurethane core and at least one further plastic material as an outer layer. Also described is the use of these moldings and composite bodies which are stable in relation to diffusion and which cause low fogging, e.g. as dashboards or door trims in the construction of vehicles, furniture, machines or apparatus.

Abstract: The present invention relates to a process for the production of composite sheet bodies by back-foaming a flexible facing with a polyurethane foam forming reaction mixture. This polyurethane foam is characterized by a density of less than 300 g/l, preferably from 20 to 150 g/l, and optionally contains isocyanurate groups. Suitable flexible facings include those having a thickness of less than 10 mm, preferably less than 2 mm. This composite bodies produced by this process are suitable for use in the automobile sector as self-supporting components. Conventional stiffening elements are not necessary to produce these self-supporting composite bodies.

Abstract: Tertiary amines having carbonate and urethane groups and optionally hydroxyl groups are produced by reacting a) a polyhydric alcohol and b) a primary-tertiary diamine with c) a carbonic acid derivative selected from the group consisting of optionally cyclic carbonates, urea, phosgene and bis-chlorocarbonates of alcohols of the same type as those used as component a). This reaction may be carried out in one or two steps. The tertiary amines produced by this process are useful as catalysts, which may optionally be incorporated into an isocyanate-reactive material, in the isocyanate addition reaction for the production of polyurethane plastics. These tertiary amines are particularly useful for the production of foam backed plastic films.

Abstract: Compounds containing ester groups and tertiary amino groups and optionally hydroxyl groups are made by reacting optionally hydroxyfunctional acetoacetic acid esters of monofunctional or polyfunctional alcohols (particularly polyfunctional polyether polyols) with primary/tertiary polyamines (particularly diamines). These compounds are useful as optionally incorporable catalysts for the isocyanate addition reaction in the production of polyurethane foams by the isocyanate polyaddition process.

Abstract: The present invention is directed to an improved process for the preparation of composite bodies by back-foaming plastics sheets with a polyurethane reaction mixture. The improvement is in using certain hydroxycarboxylic acids present in the alkali salt form as the catalyst.

Abstract: The present invention relates to a process for the production of semi-rigid foams containing urethane groups which exhibit very good flow properties during the production process. These semi-rigid foams are produced by reacting a reaction mixture of:1) polyisocyanates,2) organic compounds containing at least two isocyanate-reactive hydrogen atoms and having a molecular weight in the range from 400 to 10,000, and3) water and/or organic blowing agents.In particular, the polyisocyanates comprise a mixture of:a) 55 to 87% by weight, based on 100% by weight of the mixture, of 4,4'-diphenylmethane diisocyanate,b) 8 to 40% by weight, based on 100% by weight of the mixture, of 2,4'-diphenylmethane diisocyanate,c) 0.1 to 4% by weight, based on 100% by weight of the mixture, of 2,2'-diphenylmethane diisocyanate, andd) 5 to 35% by weight, based on 100% by weight of the mixture, of polyphenyl polymethylene polyisocyanates.

Abstract: A process for the production of polyurethane foams, in particular for the production of composite articles by back-foaming a plastics film as covering layer by the reaction ofa) one or more polyisocyanates withb) a polyol component which is free from salt groups in the presence ofc) at least one blowing agent,d) alkali metal carboxylates ande) from 0.01 to 30% by weight, based upon the weight of component b), of one or more organic compounds which are different from components a) through d), which are free from tertiary amino groups, metal and phosphorus and which have a dipole moment above 2.0 Debye.

Abstract: The present invention relates to polyurethanes with softening temperatures above 80.degree. C. which are NCO-free, which are reactive via masked isocyanates, which are essentially linear and extensively pre-lengthened, and their preparation. The polyurethanes can be used as powders which can be processed like thermoplastics and post-cured.

Abstract: A process for the production of polyurethane foams by reacting a reaction mixture consisting essentially ofa) a polyisocyanate component, withb) a polyol component free from salt groups, in the presence ofc) at least one blowing agent,d) salts of ester-functional .alpha.,.beta.-unsaturated carboxylic acids and, optionally,e) other auxiliaries and additives typically used in polyurethane chemistry.Component d) the salts of ester-functional .alpha.,.beta.-unsaturated carboxylic acids are the reaction products of (i) monohydric or polyhydric alcohols, with (ii) unsaturated dicarboxylic acids or unsaturated dicarboxylic anhydrides, which contain on a statistical average at least one alkali metal carboxylate group and at most 0.5 alcoholic hydroxyl groups per molecule. The present invention also relates to the composites produced by back-foaming of a plastic film as a surface layer wherein the foam is produced by the process described above.

Abstract: Novel powders useful in the slush molding process are produced by reacting an emulsion of either an isocyanate or an isocyanate reactive material with either an isocyanate reactive material or an isocyanate, depending upon the nature of the component used to make the emulsion in the presence of an at least partially blocked isocyanate and an organic carrier. The final reaction product is subsequently removed from the carrier.