Abstract:
The present invention relates to a method for working up distillation, residues from isocyanate production in which monomeric isocyanate present in distillation residues is recovered by means of a spray-dry method and the overall yield of monomeric isocyanate is thus significantly increased.
Abstract:
Aromatic isocyanates are produced by reacting one or more aromatic primary amines with phosgene in the gas phase. The phosgene and primary aromatic amine(s) are reacted at a temperature above the boiling temperature of the amine(s) in a reactor having a reaction space which is essentially rotationally symmetric to the direction of flow. The flow fate, averaged over the cross-section, of the reaction mixture along the axis of the essentially rotationally symmetric reaction space in the section of the reaction space in which the conversion of the amine groups into isocyanate groups is between 4 and 80% is not more than 8 m/sec. The flow rate averaged over the cross-section of the reaction mixture along the axis of the essentially rotationally symmetric reaction space in the section of the reaction space in which the conversion of the amine groups into isocyanate groups is 4 to 80% is always below the flow rate averaged over the cross-section at the start of this section.
Abstract:
The present invention relates to a process for preparing polyether polyols by base-catalyzed addition of alkylene oxides (epoxides) onto starter compounds which are solid at room temperature and have Zerevitinov-active hydrogen atoms, a particular feature of which is that visually clear and/or homogeneous products are obtained even in the absence of solvents.
Abstract:
The present invention relates to moulding compositions of polycarbonates and graft polymers and optionally further additives and components, which have, in addition to a high resistance to chemicals, a good resistance to heat, in particular a low tendency towards yellowing and a low tendency towards degradation when exposed to heat.In a particular, flameproofed embodiment, the after-burn time in a UL94 classification is furthermore reduced.
Abstract:
The invention relates to a process for preparing diaryl carbonates and/or alkyl aryl carbonates from dialkyl carbonates and aromatic hydroxy compounds using a reactive dividing wall column.
Abstract:
The present invention relates to a multilayer structure as a reflector with increased mechanical stability, which comprises a substrate layer A, a barrier layer B, a metallic reflector layer C, an optional layer D, a plasma polymer layer E, and a covering layer comprising inorganic constituents, and the covering layer does not contain UV absorber.
Abstract:
Aqueous polyurethane coating compositions are disclosed in this specification. The aqueous polyurethane coating compositions contain a polycarbonate-polyurethane resin component and a water-dilutable, ethylenically unsaturated polyurethane polyol component.
Abstract:
The present invention relates to a multilayer system comprising a base layer consisting of a thermoplastic, a primer layer, and a scratch resistant layer consisting of a scratch resistant top coat, the multilayer system being characterized in that the primer layer contains a certain UV absorber and a certain amount of acid, preferably acetic acid, is added to the scratch resistant top coat.
Abstract:
A cavity between inner and outer walls of an open-box-shaped mould is filled with a polyurethane reaction mixture, containing an isocyanate and an emulsion of an isocyanate-reactive composition with three polyols and a blowing agent, which is cured to a polyurethane containing polymer. The inner and outer wall are a fixed distance from one another and each wall comprises a bottom and sides. The mixture is fed through an inlet in the bottom of the outer wall. Before filling the cavity, the mould is turned downwards so that the mixture foams upwards, filling the cavity. The three polyols are polyether polyol obtained by adding an epoxy to carbohydrates or difunctional or higher-functional alcohols; polyether polyol obtained by adding an epoxy to an aromatic amine; and polyester polyether polyol obtained by adding an epoxy to the esterification product of an aromatic dicarboxylic acid derivative and a difunctional or higher-functional alcohol.
Abstract:
The invention relates to glass fiber reinforced polycarbonate compositions and molding compositions of the present investor and distinguished by high rigidity, high flowabillty, high processing stability, good chemical resistance and good aging resistance vis-à-vis the effects of light and heat compared with the prior art. The present invention also relates to the use of the compositions for the production of shaded articles and to shaped articles comprising the compositions according to the invention.