The present invention relates to a catalyst system comprising: A) at least one compound selected from azoles, oxazoles, thiazoles, benzotriazole, benzimidazole, benzoxazole and salts thereof; B) at least one acid catcher, which contains at least one epoxy group; and C) at least one catalyst containing an N,N,N-trisubstituted amidine structure with an amidine group content of from 12.0 to 47.0 wt %, calculated as CN2 with molecular weight=40. The invention also relates to a kit which comprises the catalyst system of the present invention and an aqueous uretdione dispersion having an acid number of from 1 to 100 KOH/g and additionally at least one carboxyl group. The invention further relates to a method for producing a polyurethane layer using the catalyst system of the present invention and said uretdione dispersion, and to the obtained polyurethane layer, and to the use of the catalyst system for curing aqueous acidic uretdione dispersions and/or for the production of paints or coatings.

The present invention relates to a specific uretdione prepolymer, and an aqueous curable composition based on the specific uretdione prepolymer. Furthermore, it pertains to a process for curing said aqueous curable composition, the cured article obtained by this process and additionally to the use of said aqueous composition for coatings, adhesives and/or sealants.

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, aliphatic and/or aromatic polyisocyanates which do not contain chemically bonded hydrophilating groups; (B) at least one polyacrylate copolymer; (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 polyacrylate copolymer (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.

The present invention provides a blocked polyisocyanate composition comprising a blocked polyisocyanate formed through blocking at least a part of isocyanate groups possessed by a polyisocyanate derived from one or two or more diisocyanates selected from the group consisting of an aliphatic diisocyanate and an alicyclic diisocyanate with an active methylene-based compound comprising a malonic acid diester, wherein a specific molar ratio calculated from contents (mol %) of isocyanurate groups, iminooxadiazinedione groups, uretdione groups, and allophanate groups is 0.05 or more and 0.60 or less.

The invention relates to a process for producing hydrophilically modified polyisocyanates having a very low content of monomeric diisocyanates, to the polyisocyanates obtainable or obtained by said process and to the use thereof for producing polyurethane plastics. The invention further relates to coating compositions containing the nonionically hydrophilized polyisocyanates and to the substrates coated with these coating compositions.

A polyisocyanate composition includes a polyisocyanate having an isocyanurate group, derived from one or more types of diisocyanates selected from the group consisting of an aliphatic diisocyanate and an alicyclic diisocyanate, UV absorption peaks of a trimeric equivalent of the diisocyanate and a tetrameric equivalent of the diisocyanate being present in a spectrum of the polyisocyanate composition measured by gel permeation chromatography, the ratio ((B)/(A)) of the height (B) of the UV absorption peak of the tetrameric equivalent of the diisocyanate to the height (A) of the UV absorption peak of the trimeric equivalent of the diisocyanate being 0.01 to 3, and the content of a volatile component produced from storage for three months at 60 C. being 0.3% by mass or less with respect to the total mass of the polyisocyanate composition prior to storage, the volatile component having been removed from the polyisocyanate composition in advance.

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 present invention provides a system comprising an allophanate composition comprising a neutralized polyol, a polyuretdione resin, a tertiary amine catalyst, an additive package, and a reducer; and a neutralized basecoat comprising an inorganic salt and a pigment. The present invention further provides a method of making an allophanate system comprising combining a neutralized polyol with a polyuretdione resin in the presence of a tertiary amine catalyst, an additive package, and a reducer to produce an allophanate composition, and contacting the allophanate composition with a neutralized basecoat comprising an inorganic salt and a pigment. The system may be used to make coatings, adhesives, castings, composites, and sealants in which clear-coating on neutralized pigmented basecoats is much improved in comparison to coating on non-neutralized basecoats.

The present invention provides a system comprising an allophanate composition comprising a neutralized polyol, a polyuretdione resin, a tertiary amine catalyst, an additive package, and a reducer and a neutralized basecoat comprising an acid scavenger and a pigment. The resulting allophanate system may be used to make coatings, adhesives, castings, composites, and sealants in which clear-coating on neutralized pigmented basecoats is much improved in comparison to non-neutralized basecoats.

The present invention provides a reaction mixture comprising a polyuretdione resin, a neutralized polyol, an acid-blocked tertiary amine catalyst, and optionally, an additive package selected from the group consisting of flow control additives, and wetting agents, and solvents, wherein the acid has a pK.sub.a of greater than 4.82. Compositions made from the reaction mixture of the present invention may be catalyzed at temperatures from room temperature to 130 C. and are particularly applicable in or as coatings, adhesives, castings, composites, and sealants with good performance and extended pot-life.