Abstract: This invention relates to a process for producing prepolymers, which contain isocyanate terminal groups and which have a very low content of free isocyanate starting materials, from polyester polyols and polyisocyanates.

Abstract: Rigid, closed-cell polyurethane foams are produced by a RIM process by reacting an organic polyisocyanate with an isocyanate-reactive mixture in which a significant amount of a bio-based polyol is present. The foams produced by this process are characterized by improved heat sag and heat distortion temperature.

Abstract: Aliphatic polycarbonate homo- and co-polymers are obtained by ring-opening homo- or co-polymerization of cyclic carbonates by DMC catalysis. These polymers are useful in the production of polyurethanes.

Abstract: Molded polyurethane articles having improved flex modulus and impact strength are produced by subjecting a polyurethane-forming reaction mixture which has been introduced into a mold to a static electric field. The static electric field must have a field strength which is less than the dielectric strength of the polyurethane being produced but sufficiently strong to align the hard segment dipoles of the polyurethane.

Abstract: Rigid foams having excellent compression strength, dimensional stability, flame retardance and adhesion are produced by reacting an active hydrogen compound having at least two functionalities with a polyisocyanate compound in the presence of a catalyst and a blowing agent comprising either water alone or a mixture of water and a low boiling compound, wherein (1) the polyisocyanate compound is a prepolymer obtained by reacting a polymeric MDI with 5 to 30% by weight, based on the polymeric MDI, of a polyether polyol and/or polyester polyol having a hydroxyl value of at most 100 mg KOH/g, and (2) the number of isocyanate groups in the polyisocyanate compound is at least 1.5 times by mole as large as the number of active hydrogen atoms in the active hydrogen compound and water.

Abstract: Polyisocyanates of the diphenyl methane series having reduced color values are obtained by a) reacting aniline and formaldehyde in the presence of an acid catalyst to form a polyamine, b) neutralizing the reaction mixture containing polyamine with a base, c) separating the neutralized mixture into the aqueous and the organic phases, d) adding a base to the organic phase and then e) phosgenating the resulting polyamine to produce the corresponding polyisocyanate.

Abstract: Polyurethane molded articles are produced from a flowable polyol-polyisocyanate reaction mixture on a shot-wise basis. The flowable reaction mixture is formed by combining the components of that mixture in the mixing chamber of a mixhead. The contents of the mixhead are introduced (preferably via an outlet pipe) into a mold in a manner such that the mixing chamber is substantially emptied in each case. Any ambient gas in the mixing chamber is then removed before the respective next shot is initiated.

Abstract: An axial conveyor is described, in particular for conveying gas/liquid dispersions, wherein the conveying elements comprise a wall-sweeping edge pointing in the direction of the pressure side of the conveying elements. The axial conveyor is particularly suitable as a circulating member in loop reactors. A process comprising conveying gas/liquid dispersions as well as a process for carrying out chemical reactions directly reacting gas with gases not completely dissolved in a liquid medium, or optionally in the presence of finely divided solids, through the use of an axial conveyor, is also disclosed.

Abstract: Segmented polyurethane/ureas useful for the production of spandex are produced by chain extending, in the presence of a solvent, an isocyanate-terminated prepolymer prepared by reacting a stoichiometric excess of an isocyanate with an isocyanate-reactive component which includes: (1) from about 5 to about 30 equivalent percent of a polyoxy-propylene diol having a molecular weight of at least 1500 Da and an unsaturation level less than or equal to 0.03 meq/g; (2) from about 20 to about 60 equivalent percent of a polytetramethylene ether glycol having a molecular weight less than 1000 Da; and (3) from about 25 to about 65 equivalent percent of a polytetramethylene ether glycol having a molecular weight greater than or equal to 1000 Da.

Abstract: From an extruded panel manufactured continuously by means of a twin-belt conveyor, shorter sections may be profitably removed by a cutting device equipped with an adjustable program controller which fixes optimum start-of-cut positions related to a reference point and lying immediately in front of the edges of the extruded panel. The cutting blade is brought into the optimum start-of-cut position in good time before each cut.

Abstract: Flowable reaction components of a reaction mixture which form solid or foamed material comprising filling material are transported from a storage container to a high-pressure mixing head in pressure stages by the use of gear pumps connected in series without major wear of the gear pumps.

Abstract: The invention provides a process for the production of flexible to semi-rigid polyurethane shaped articles with a compacted edge zone of given hardness and a significantly more flexible cell core, so-called integral foams, in which non-combustible mixtures of fluoroalkanes which comprise 1,1,1,3,3-pentafluorobutane (R 365mfc) are employed as physical blowing agents.

Abstract: The present invention relates to polyol mixtures which are suitable for the preparation of rigid polyurethane foams and comprise addition products of alkylene oxide on aromatic di- or polyamines, and rigid foams prepared with these polyol mixtures.

Abstract: The invention relates to double-metal cyanide (DMC) catalysts for preparing polyether polyols by the polyaddition of alkylene oxides on to starter compounds containing active hydrogen atoms, wherein the DMC catalysts are composed of: a) at least one DMC compound; b) at least one organic complexing ligand which is not a coronand; and c) at least one coronand. The DMC catalysts of the present invention have increased activity compared to known catalysts.

Abstract: The pot life of an isocyanate formulation is controlled by including a chain extender having (a) at least two secondary amine groups, (b) no primary amine groups, and (c) a reactivity low enough that the chain extender will not react sufficiently with isocyanate groups present in the isocyanate formulation to increase the viscosity of the isocyanate formulation to more than 2000 mPa·s within 5 seconds in the isocyanate formulation.

Abstract: Polyurethane elastomers are produced by reacting a polyether and/or polyester polyol having a starter functionality of at least 2 with an NCO-terminated prepolymer produced with a polyether and/or polyester polyol having a starter functionality of at least 4. These polyurethane elastomers exhibit improved processing characteristics combined with a high heat distortion temperature.

Abstract: A supported catalyst coated with gold particles is produced. This supported catalyst is used to oxidize unsaturated hydrocarbons in the gas phase with a hydrogen/oxygen mixture.

Abstract: 1,4-diaminonaphthalene and/or 1,5-diaminonaphthalene are produced by (a) reacting naphthalene with a halogen, (b) optionally, separating 1,4-dihalogen naphthalene or 1,5-dihalogen naphthalene from the mixture from step (a), and (c) reacting the mixture from step (a) or the 1,4-dihalogen naphthalene or the 1,5-dihalogen naphthalene from step (b) with ammonia and/or an organic amine in the presence of a catalyst.

Abstract: Dinitrotoluene (DNT) is produced by the adiabatic nitration of toluene with nitric acid at a temperature of from about 60 to about 200° C. and at a molar ratio of toluene to nitric acid of from about 1:1.5 to about 1:3.0. The reaction mixture thus-obtained is concentrated to a water content of up to 30% by weight. The dinitrotoluene which is present in the reaction mixture is at least partially (if not completely) removed from the reaction mixture either before or after concentration of the reaction mixture. The DNT which is still present in the vapor generated during the concentration of the reaction mixture is kept liquid by the addition of a solvent to the vapors generated during concentration of the reaction mixture. The solvent added to vapor, together with any DNT present in the vapor is recovered. This solvent/DNT mixture may be recycled directly to the reaction vessel. The solvent/DNT mixture may also be separated. The separated solvent may be recycled to the solvent addition step.

Abstract: Safety clothing is produced by molding polyether-based plastic-forming compositions. Particularly preferred articles of safety clothing produced by this process are safety shoe soles.