Abstract: The present invention relates to an improved process for the preparation of polyisocyanates with a biuret structure by continuous reaction of excess amounts of organic diisocyanates having exclusively aliphatically and/or cycloaliphatically bonded isocyanate groups with organic diamines having exclusively aliphatically and/or cycloaliphatically bonded primary amino groups at elevated temperatures by 2-stage addition of the isocyanate component.

Abstract: The present invention relates to polyurethane powder coating compositions that do not split off blocking agents and have a low stoving temperature. The powder coating compositions contain a hydroxyl functional binder component having a content of carboxyl groups of from 0.5 to 2.0 wt. %, a polyaddition compound, at least one zinc compound as a hardening catalyst, and a compound reactive to carboxyl groups.

Abstract: This invention relates to coating compositions and more particularly to highly productive coating compositions that quickly harden for sanding or buffing by incorporating therein a polyisocyanate adduct mixture into the coating composition as the crosslinking material. Such coatings are particularly useful for refinishing automobiles and trucks.

Abstract: The invention provides a process for isocyanate dimerization (uretdione formation) and a process for preparing polyisocyanates having a high content of uretdione groups, using specific phosphines as catalysts. The phosphines have one or two tertiary alkyl radicals bound directly to phosphorus.

Abstract: The invention relates to the use of heterocycles containing trivalent phosphorus as a ring member as catalysts for isocyanate modification and to a process for preparing polyisocyanates of the trimer type.

Abstract: The invention relates to a new industrial process for producing low-monomer-content organic polyisocyanates by oligomerization of organic diisocyanates in a two-phase system.

Abstract: The present invention relates to innovative polyisocyanate mixtures comprising cycloaliphatic structural elements and containing exclusively linear-aliphatically attached free isocyanate groups, to a process for preparing them and to their use as a starting component in the production of polyurethane plastics, more particularly as a crosslinker component in polyurethane coating materials and coatings.

Abstract: 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.

Abstract: The invention relates to the use of specific pyridines as catalysts for the dimerization of isocyanates (uretdione formation) and a process for preparing polyisocyanates having a high content of uretdione groups.

Abstract: The invention relates to polyisocyanates containing allophanate groups and silane groups, to a process for preparing them and to their use as a starting component in the production of polyurethane polymers, more particularly as a crosslinker component in polyurethane paints and coatings.

Abstract: The invention provides a process for isocyanate dimerization (uretdione formation) and a process for preparing polyisocyanates having a high content of uretdione groups, using specific phosphines as catalysts. The phosphines have one or two tertiary alkyl radicals bound directly to phosphorus.

Abstract: The present invention relates to polyurethane powder lacquers with optimized flow behavior, a process for their production, a process for coating substrates with these powder lacquers, as well as substrates coated with these powder lacquers.

Abstract: The present invention provides a process for preparing aqueous solutions of NCO group blocked resins having polyimide structures and optionally, polyamide structures. The process comprises the steps of preparing a polymer from at least one polyisocyanate, at least one tricarboxylic monoanhydride and/or at least one tetracarboxylic anhydride, and optionally, tricarboxylic acids, tetracarboxylic acids and/or dicarboxylic acids, at least one NH-functional lactam and/or 3,5-dimethylpyrazole and/or butanone oxime. The reaction mixture is subsequently reacted with a base, and the resulting resin is dissolved in water. The resins provide high-grade, highly flexible coatings having the excellent properties and chemical resistance typical of polyamideimides.

Abstract: Biuret group-containing polyisocyanates are produced having an isocyanate functionality of at least 4 are prepared by reacting polyisocyanates having a functionality of at least 2.8 with water as the biuretizing agent. Most preferably water is used as the sole biuretizing agent. The preparation is useful as a curing agent in crosslinkable coating compositions. The coating composition can be used as an automotive clearcoat over a conventional pigmented basecoat, or as a basecoat or monocoat or even as a primer or sealer when a suitable amount of pigment is incorporated therein.

Abstract: A process for preparing polyisocyanate-modified polycarboxylic acids by conversion of anhydride-group-free polycarboxylic acids with isocyanate-functional compounds. The process includes reacting A) an anhydride-group-free polycarboxylic-acid component with B) an isocyanate-functional component having an (average) isocyanate functionality of at least 1.8, at an equivalent ratio of carboxylic acid groups to isocyanate groups of from 1.2:1 to 120:1. The polyisocyanate-modified polycarboxylic acids are solid below 40° C. and liquid above 130° C., and have an average carboxylic acid functionality of at least 1.8, a content of free carboxylic acid groups of from 4.0 wt. % to 80.0 wt. % and a content of amide groups of from 0.4 wt. % to 32.5 wt. %.

Abstract: This invention relates to coating compositions and more particularly to highly productive coating compositions that quickly harden for sanding or buffing by incorporating therein a polyisocyanate adduct mixture into the coating composition as the crosslinking material. Such coatings are particularly useful for refinishing automobiles and trucks.

Abstract: The present invention relates to a novel process for the preparation of polyaddition products, to the products obtainable by this process and to their use as starting components in the production of polyurethane plastics. The process includes the reaction of A) polyisocyanates with uretdione groups having a mean isocyanate functionality of at least 2.0, optionally with the concomitant use of B) other diisocyanates and/or polyisocyanates, different from A, in an amount of up to 70 wt. %, based on the total weight of components A) and B), with C) polyols in the molecular weight range 62-2000 having a mean functionality of at least 2.0, or mixtures of polyols and optionally D) other isocyanate-reactive monofunctional compounds in an amount of up to 40 wt. %, based on the total weight of components C) and D). An equivalent ratio of isocyanate groups to isocyanate-reactive groups of 1.8:1 to 0.

Abstract: The present invention relates to a process for preparing self-crosslinking polyurethane dispersions by I) reacting a1) polyisocyanates with a2) at least one hydroxyl component having an average OH functionality of ?2 and a number average molecular weight of 62 to 2500 g/mol, wherein the hydroxyl component contains at least one acid-functional compound containing at least one isocyanate-reactive group, to form an NCO-functional and optionally OH-functional prepolymer, II) then reacting the NCO-functional and optionally OH-functional prepolymer with a3) a hydroxyl component having an average OH functionality of >1 and a4) optionally another polyisocyanate component, which may be the same as or different from a1), to form an OH-functional and NCO-free polyurethane, III) adding a blocked polyisocyanate either before, during or after the reaction of steps I) and II), or forming a blocked polyisocyanate in situ from a polyisocyanate and a blocking agent after the reaction of step II) has taken place, IV) neutral

Abstract: A method of dimerizing isocyanates including reacting the isocyanates in the presence of phosphines containing at least one directly phosphorus-attached bicyclic, cycloaliphatic radical. The polyisocyanate compositions obtained as described above can be used in mouldings, coating materials, adhesives, sealants or adjuvants that further include the polyisocyanate compositions and one or more materials selected from antioxidants, light stabilizers, pigments, fillers, additives, levelling assistance, defoamers and matting agents. The coating materials, adhesives or sealants can be used to coat substrates.

Abstract: The present invention relates to novel blocked, elimination-free polyurethane (PUR) crosslinking agents, to a process for their preparation and to their use as starting components for the production of polyurethane plastics, especially as crosslinking agents for thermally crosslinkable powder coatings.