The present invention relates to a process for the production of a rigid polyurethane foam or rigid polyisocyanurate foam, comprising the reaction of at least one polyisocyanate and of a polyol composition (PZ), where the polyol composition (PZ) comprises at least one compound having at least two hydrogen atoms reactive toward isocyanate groups and at least one compound (I) selected from the group consisting of dicarboxylic diesters of dicarboxylic acids having from 2 to 18 C atoms and tricarboxylic triesters of tricarboxylic acids having from 3 to 18 C atoms, where at least one blowing agent is used during the reaction. The present invention further relates to rigid polyurethane foams or rigid polyisocyanurate foams obtainable or obtained by such a process, and also to a polyol composition (PZ) at least comprising one compound having at least two hydrogen atoms reactive toward isocyanate groups and at least one compound (I) selected from the group consisting of dicarboxylic diesters of dicarboxylic acids having from 2 to 18 C atoms and tricarboxylic triesters of tricarboxylic acids having from 3 to 18 C atoms. The present invention also relates to the use of such a polyol composition (PZ) for the production of rigid polyurethane foams or rigid polyisocyanurate foams, and also to the use of a rigid polyurethane foam or rigid polyisocyanurate foam of the invention as, or for the production of, insulation materials, preferably insulation sheets, sandwich elements, hot-water tanks, boilers, coolers, insulation foams, refrigerators or freezers.

The present invention relates to a multi-aziridine compound having: a) at least 2 of the following structural units (A) whereby R.sub.1 is H; R.sub.2 and R.sub.4 are independently chosen from H, a linear group containing from 1 to 8 carbon atoms and optionally containing one or more heteroatoms, a branched or cyclic group containing from 3 to 8 carbon atoms and optionally containing one or more heteroatoms, phenyl, benzyl, or pyridinyl; R.sub.3 is chosen from a linear group containing from 1 to 8 carbon atoms and optionally containing one or more heteroatoms, a branched or cyclic group containing from 3 to 8 carbon atoms and optionally containing one or more heteroatoms, phenyl, benzyl, or pyridinyl; or R.sub.2 and R.sub.3 (in case R.sub.2 is different than H) may be part of the same cyclic group containing from 3 to 8 carbon atoms; R and R are independently H or an aliphatic hydrocarbon group containing from 1 to 12 carbon atoms; and b) a molecular weight of at least 600 Daltons, wherein the molecular weight is determined using MALDI-TOF mass spectrometry according to the description.

The present invention relates to a multi-aziridine crosslinker composition, characterized in that the multi-aziridine crosslinker composition is an aqueous dispersion having a pH ranging from 8 to 14 and comprises a multi-aziridine compound in dispersed form, wherein said multi-aziridine compound has: a. from 2 to 6 of the following structural units A: whereby R.sub.1 is H, R.sub.2 and R.sub.4 are independently chosen from H or an aliphatic hydrocarbon group containing from 1 to 4 carbon atoms, R a is an aliphatic hydrocarbon group containing from 1 to 4 carbon atoms, m is 1, b. one or more linking chains wherein each one of these linking chains links two of the structural units A; and c. a molecular weight in the range from 500 to 10000 Daltons wherein the molecular weight is determined using MALDI-TOF mass spectrometry according to the description. ##STR00001##

The present application relates to aziridine functional compounds with reduced genotoxicity and good crosslinking efficiency, for use in the preparation of, for example, coatings. ##STR00001##

The present invention relates to an aqueous coating composition comprising a multi-aziridine compound and a carboxylic acid functional polymer, characterized in that (i) the composition is an aqueous dispersion having a pH ranging from 8 to 14, (ii) the aqueous dispersion comprises particles X which particles X comprise multi aziridine compound and particles Y which particles Y comprise carboxylic acid functional polymer, and (iii) said multi-aziridine compound has: a) from 2 to 6 of the following structural units A: b) one or more linking chains wherein each one of these linking chains links two of the structural units A; and c) a molecular weight in the range from 500 to 10000 Daltons. ##STR00001##