The present invention relates to a new process for preparing polyisocyanates containing isocyanurate groups and being flocculation-stable in solvents from (cyclo)aliphatic diisocyanates.

The present invention relates to a process for the effective removal of residual monomeric aliphatic isocyanate from a reaction mixture comprising aliphatic polyisocyanate comprising (i) providing a reactor containing a scavenger comprising a zeolitic material, wherein the zeolitic material comprises SiO.sub.2 and optionally X.sub.2O.sub.3 in its framework structure, wherein X is a trivalent element; (ii) providing a reaction mixture comprising aliphatic polyisocyanate and monomeric aliphatic isocyanate; (iii) contacting the scavenger in the reactor with the reaction mixture provided in (ii) at a temperature lower than the boiling point of the residual monomeric aliphatic isocyanate for obtaining a product comprising aliphatic polyisocyanate with a reduced monomeric aliphatic isocyanate content, wherein if the zeolitic material comprises X.sub.2O.sub.3, the zeolitic material has an SiO.sub.2 to X.sub.2O.sub.3 molar ratio higher than 2.8:1, preferably higher than 5:1, more preferably higher than 30:1.

The invention relates to a process for producing a composite polyisocyanurate material, comprising the following steps: a) providing a polyisocyanate composition A) which comprises oligomeric polyisocyanates and is low in monomeric diisocyanates, “low in monomeric diisocyanates” meaning that the polyisocyanate composition A) has a content of monomeric diisocyanates of not more than 20% by weight, and b) catalytically trimerizing the polyisocyanate composition A) in the presence of at least one fibrous filler B) and of a trimerization catalyst C) to give the composite polyisocyanurate material, where the trimerization catalyst C) comprises at least one metal salt and/or quaternary ammonium salt. The invention further relates to composite polyisocyanurate materials obtainable by the process according to the invention and to the use thereof for production of a component, and to components consisting of or comprising a composite polyisocyanurate material according to the invention.

A polymer composite composition for use in high temperature applications such as furnaces, heat shields and aeronautical jet and rocket motors. In a particular application, the disclosed composition is applied to the manufacture of rocket motor cases, or parts thereof, to provide rigid thermal protection (RTP). The polymer composite composition comprises cyanate ester resin, fine lengths of carbon fibre and refractory filler material.

The present invention relates to the use of metal salts of polymeric alcohols as storage-stable thermolatent catalysts for the manufacture of isocyanurate and polyisocyanate polymers.

The present invention relates to curable photochromic compositions which include a polycarbodiimide, an at least di-functional first carboxylic acid functional material having at least two carboxylic acid groups, an optional second carboxylic acid functional material having at least three carboxylic acid groups, a photochromic compound, and an aprotic organic solvent. The curable photochromic compositions have an equivalents ratio of carbodiimide equivalents of the polycarbodiimide to a total carboxylic acid equivalents of the first and optional second carboxylic acid functional materials of from 0.5:1 to 10:1 when the second carboxylic acid functional material is not present; and from 0.5:1 to 3:1 when the second carboxylic acid functional material is present. The present invention, more particularly, relates to curable photochromic coating compositions, and curable photochromic adhesive compositions.

The present invention provides a polyisocyanate composition comprising at least one isocyanate compound selected from the group consisting of an aliphatic isocyanate and an alicyclic isocyanate as a skeleton, wherein an average value of a total number of isocyanate groups blocked with a blocking agent and not blocked with a blocking agent per polyisocyanate molecule is 2 or more, and among the isocyanate groups in the polyisocyanate composition, 1 mol % or more and 99 mol % or less are blocked with a blocking agent, and the like.

The present invention provides a polyisocyanate composition comprising at least one isocyanate compound selected from the group consisting of an aliphatic isocyanate and an alicyclic isocyanate as a skeleton, wherein an average value of a total number of isocyanate groups blocked with a blocking agent and not blocked with a blocking agent per polyisocyanate molecule is 2 or more, and among the isocyanate groups in the polyisocyanate composition, 1 mol % or more and 99 mol % or less are blocked with a blocking agent, and the like.

The present invention relates to polymerizable compositions which contain components that can be crosslinked both via isocyanurate bonds and by a radical reaction mechanism. The invention further relates to methods by way of which polymers can be produced from said compositions.

The invention relates to a process of preparing allophanate- and/or thioallophanate group-containing compounds comprising the following steps: reacting A) at least one component having at least one uretdione group with B) at least one component having at least one hydroxyl and/or thiol group, in the presence C) of at least one catalyst, containing a structural element of the general formulae (I) and/or (II), wherein R1, R2, R3, R4, R5 and R6 independently of each other represent the same or different radicals meaning saturated or unsaturated, linear or branched, aliphatic, cycloaliphatic, araliphatic or aromatic organic radicals with 1 to 18 carbon atoms that are substituted or unsubstituted and/or have heteroatoms in the chain, the radicals being capable of forming, even when combined with each other and optionally together with an additional heteroatom, rings with 3 to 8 carbon atoms that can optionally be further substituted, wherein R3, R4, R5 and R6 independently of each other also can represent hydrogen, and R7 represents hydrogen or a carboxylate anion (COO—), the at least one component A) having at least one uretdione group being polyaddition compounds A2) that can be obtained by reacting isocyanate-functional uretdione groups A1) with alcohols and/or amines that have a free isocyanate group content of less than 5 wt. % in their solvent-free form.