摘要:
This invention concerns a process for the manufacture of flexible polyurethane foams from urethane-modified aromatic polyisocyanates having an NCO content of 15 to 30 percent by weight and a viscosity of 100 to 2000 centipoises at 20.degree. C., which are obtained by reaction of a mixture of diphenylmethane diisocyanates and polyphenylene polymethylene polyisocyanates containing 55 to 85 percent by weight of diphenylmethane diisocyanate based on the total weight of the polyisocyanate mixture and a hydroxyl compound with 2 to 4 Zerewitinoff active hydrogen atoms and a molecular weight of 60 to 1500, in an equivalency ratio of NCO groups to active hydrogen atoms of the hydroxyl compound of 2:1 to 60:1, polyols, catalysts, blowing agents, and optionally, chain extenders, auxiliaries, and additives.
摘要:
The invention relates to the preparation of isocyanates by phosgenation of amines in the gas phase, with these isocyanates having a comparatively low proportion of color-imparting compounds.
摘要:
Processes comprising providing an amine reactant, and reacting the amine reactant with a stream of phosgene in a reaction zone to form a product comprising a corresponding isocyanate, wherein the phosgene stream has a CO content of 0.5% by weight or more.
摘要:
Isocyanates are produced by reaction of primary amines with phosgene in the gas phase. In this process, the reaction is terminated by guiding the reaction mixture from the reaction chamber through a cooling stretch into which liquids are injected. Direct cooling takes place in the cooling stretch in one stage in two or more cooling zones connected in series.
摘要:
The invention relates to a process for the preparation of isocyanates in the gas phase, in which the possibilities for back-mixing and byproduct formation are reduced by improving the mixing of the starting materials in a tubular reactor.
摘要:
The present invention relates to a process for preparing (cyclo)aliphatic diisocyanates and triisocyanates corresponding to the formula R—(NCO)n (I), wherein R represents a (cyclo)aliphatic hydrocarbon group having up to 15 carbon atoms, provided that there are at least two carbon atoms between two nitrogens, n represents the number 2 or 3, by a) separately heating phosgene and a diamine or triamine corresponding to the formula R—(NH2)n (II), to a temperature of 200° C. to 600° C., wherein the amine may optionally be diluted with an inert gas or with the vapors of an inert solvent, b) optionally passing the reactants over torque-producing baffles and c) continuously reacting phosgene and the amine in the gas phase in a reaction chamber without moving parts and with constrictions of the walls in the region of the reaction zone.
摘要:
Thermoplastic molding materials containA) from 10 to 99.5% by weight of a thermoplastic polymer selected from the group consisting of the polyoxymethylenes, polyolefins, polyesters, polycarbonates, polystyrene, ABS, ASA, SAN, polyamides or poly(meth)acrylates or mixtures thereof,B) from 0.5 to 80% by weight of a thermoplastic polyurethane having a melting point of
摘要:
Diisocyanates are produced by gas-phase phosgenation of aliphatic diamines having two primary amino groups in the 1,2- or 1,3-position to one another or by cycloaliphatic diamines having two primary amino groups in the 1,2- or 1,3-position to one another.
摘要:
A diisocyanate corresponding to the formula ##STR1## in which R.sup.1, R.sup.2, R.sup.3, m and n are as defined herein is prepared by phosgenating a diamine corresponding to the formula ##STR2## in which R.sup.1, R.sup.2, R.sup.3, m and n are as defined herein. The diisocyanate may contain C.sub.1 -C.sub.12 -monoalkyl-substituted methylene-bis-(cyclohexylisocyanate)isomers in an amount of up to 40 wt. %. These new diisocyanates which are liquid at room temperature and compatible with polyols are particularly useful in the production of polyurethanes.
摘要:
A curable composition consisting ofA. 100 parts by weight of an epoxy resin,B. from 4 to 100 parts by weight of a conventional curing agent for epoxy resins, andC. from 0.1 to 5 parts by weight of an N-acylimidazole which possesses an aromatic acyl component which is substituted at the two positions ortho to the carbonyl groupcan be used to produce moldings, coatings, finishes, adhesives and composite fiber materials.