The present invention relates to a multi-aziridine compound having: ⋅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 1-4 carbon atoms, R.sub.3 is an aliphatic hydrocarbon group containing from 1-4 carbon atoms, R′═H or an aliphatic hydrocarbon group containing from 1 to 4 carbon atoms; R″ and R′″ are independently chosen from an aliphatic hydrocarbon group containing from 1 to 4 carbon atoms, a cycloaliphatic hydrocarbon group containing from 4 to 12 carbon atoms or an aromatic hydrocarbon group containing from 6 to 12 carbon atoms, 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 600 Daltons to 5000 Daltons.

##STR00001##

The present invention relates to a multi-aziridine crosslinker composition, characterized in that the composition is an aqueous dispersion having a pH ranging from 9 to 14 and comprising a multi-aziridine compound in dispersed form, wherein said multi-aziridine compound has: a. from 2 to 6 of the following structural units A: (A) whereby R.sub.1, R.sub.2, R.sub.3 and R.sub.4 are H; m is 1, R′ and R″ are according to (1) or (2): (2) R′═H or an aliphatic hydrocarbon group containing from 1 to 14 carbon atoms, and R″=an alkyl group containing from 1 to 4 carbon atoms, CH2-O—(C═O)—R′″ or CH2-O—R″″, whereby R′″ is an alkyl group containing from 4 to 12 carbon atoms and R″″ is an alkyl group containing from 1 to 14 carbon atoms, (2) R′ and R″ form together a saturated cycloaliphatic hydrocarbon group containing from 5 to 8 carbon atoms; 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 600 to 10000 Daltons.

##STR00001##

The invention relates to particular (aziridinyl hydroxy)-functional organic component. The invention further relates to liquid compositions comprising said (aziridinyl hydroxy)-functional organic component. The invention further relates to coating compositions comprising said (aziridinyl hydroxy)-functional organic component. The invention further relates to liquid coating compositions comprising said (aziridinyl hydroxy)-functional organic component. The invention further relates to a kit-of-parts comprising in one of its parts a liquid composition comprising a particular (aziridinyl hydroxy)-functional organic component. The invention further relates to cured forms of said liquid compositions, coating compositions, and liquid coating compositions. The invention further relates to articles comprising the (aziridinyl hydroxy)-functional organic component and/or the liquid compositions and/or the liquid coating compositions and/or their cured forms. The invention further relates to various uses of the (aziridinyl hydroxy)-functional organic component and/or said liquid compositions, and/or said liquid coating compositions, and/or said kit-of-parts and/or said cured forms.

The invention relates to a process for the preparation of polyisocyanates with dimer, trimer and/or allophanate and optionally urethane structure.

The present invention provides a reaction mixture comprising a blend of a first isocyanate-based uretdione-containing resin and a second isocyanate-based uretdione-containing resin, a neutralized polyol and a tertiary amine catalyst, and optionally, an additive package selected from the group consisting of flow control additives, pigments (colorants), wetting agents, and solvents, wherein the first isocyanate and the second isocyanate are different. The first isocyanate-based uretdione-containing resin and the second isocyanate-based uretdione-containing resin may be cold blended or hot blended. Coatings, adhesives, castings, composites, and sealants made from hot blended formulations exhibit superior performance over those made from cold blended formulations.

The present invention relates to novel polyisocyanurate plastics which are obtainable by catalytic trimerization of a polyisocyanate composition A) which contains oligomeric polyisocyanates and is low in monomeric diisocyanates. “Low in monomeric diisocyanates” means that the polyisocyanate composition A) has a content of monomeric diisocyanates of at most 20% by weight. The invention further relates to the use of these polyisocyanurate plastics for production of coatings, films, semi-finished products and mouldings, and to a process for producing polyisocyanurate plastics comprising the following steps: (a) providing a polyisocyanate composition A) which contains 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 at most 20% by weight; (b) catalytically trimerizing the polyisocyanate composition A).

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 R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5 and R.sup.6 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 R.sup.3, R.sup.4, R.sup.5 and R.sup.6 independently of each other also can represent hydrogen, and R.sup.7 represents hydrogen or a carboxylate anion (COO.sup.−), 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.

The present invention provides a reaction mixture comprising a hot blend of a first isocyanate-based uretdione resin and a second isocyanate-based uretdione resin, a neutralized polyol and a tertiary amine catalyst, and optionally, an additive package selected from the group consisting of flow control additives, pigments (colorants), wetting agents, and solvents, wherein the first isocyanate and the second isocyanate are different. The isocyanate-based uretdiones that have been hot blended together produce coatings, adhesives, castings, composites, and sealants, which exhibit better performance properties (such as microhardness) than those coatings, adhesives, castings, composites, and sealants produced from the constituent isocyanate-based uretdiones alone.

The present invention provides a polyisocyanate composition and the like that contain a polyisocyanate compound represented by general formula (I), (II), (III) or (IV) (wherein the pluralities of R.sup.11, R.sup.21, R.sup.31 and R.sup.41 each independently represent an organic group, at least one of the pluralities of R.sup.11, R.sup.21, R.sup.31 and R.sup.41 is a group represented by general formula (V) (wherein each of the plurality of Y.sup.1 independently represents a single bond or the like, R.sup.51 represents a hydrogen atom or the like, and the wavy line indicates a bonding site) or the like, and in general formula (III), R.sup.32 represents a residue in which one hydroxyl group has been removed from a monohydric or polyhydric alcohol). ##STR00001##

The invention relates to aqueous uretdione group-containing compositions comprising or consisting of (A) at least one uretdione group-containing curing agent based on aliphatic, cycloaliphatic, araliphatic, and/or aromatic polyisocyanates which do not contain chemically bonded hydrophilating groups; (B) at least one hydroxy group-containing polyol which contains at least one chemically bonded carboxylic acid group; (C) optionally solvents; and (D) optionally auxiliary agents and additives; wherein the quantity ratio of the components (A) and (B) is measured such that the molar ratio of the NCO groups of the curing agent (A), said groups being provided in the form of uretdione, to the NCO reactive groups of the polyol (B) equals 3.0:0.5 to 0.5:3.0, and A and B are provided as a physical mixture. The invention additionally relates to a method for producing a polyurethane layer using the aqueous uretdione group-containing composition according to the invention, to the polyurethane layer obtained therefrom, and to a substrate which is coated with or adhered to the polyurethane layer.