A composition for forming a polyiso-urea includes a capped polycarbodiimide and a polyol. The capped polycarbodiimide comprises the reaction product of a diisocyanate and a monoisocyanate in the presence of an oxygen scavenger and a carbodiimidization catalyst and in the absence of solvent, has 0.25 wt. % or less of free isocyanate groups, and is a liquid at 25 C. A polyiso-urea comprises the reaction product of the capped polycarbodiimide and the polyol.

The invention relates to novel polycarbodiimides which are capable of easy and reliable production, have high average molar masses and effect excellent hydrolysis stabilization, to processes for the production thereof and to the use thereof.

A process for the preparation of multifunctional polycarbodiimides, which are used as crosslinking agents, in which the polycarbodiimide is prepared by reacting mono- and polyisocyanates in the presence of a mono- or polyisocyanate that contains one or multiple additional reactive functional groups and in the presence of a carbodiimide catalyst, and thereafter terminating or chain extending the polycarbodiimide chain. Between 0 and 10% of an organic solvent and/or between 0 and 30% of a plasticizer and/or between 0 and 30% of a surface active component is added to the product during, before or after the polycarbodiimide forming reaction and/or the capping reaction and/or the chain extending reaction. Further, the invention relates to a coating mixture in which the polycarbodiimide is used as crosslinking agent and to the cured material obtained with the coating mixture.

The invention relates to the use of carbodiimide-containing compositions for controlling pot life in the production of polyurethane (PU)-based systems, preferably PU elastomers, PU adhesives, PU casting resins or PU foams.

A polycarbodiimide composition is obtained by subjecting a reaction product of a straight-chain aliphatic diisocyanate and alcohols to carbodiimidization, and the alcohols include a polyol and a monool; in the alcohols, a mole ratio (hydroxyl group derived from polyol/hydroxyl group derived from monool) of the amount of hydroxyl groups derived from the polyol to the amount of hydroxyl groups derived from the monool is below 2.0; and a carbodiimide equivalent of the polycarbodiimide composition is 300 g/mol or more and below 550 g/mol.

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.

An aqueous solution includes a polyalkylene glycol terminated poly-carbodiimide of formula 1:

##STR00001##

where: R.sub.1 is an aliphatic group from about 5 to about 12 carbon atoms, an isosorbide moiety, a 1,3-furan moiety, an L-lysine alkyl ester moiety, a rosin moiety, a cycloaliphatic unsaturated moiety, or a cardanol moiety; R.sub.2 is hydrogen or a methyl group; R.sub.3 is a methyl, ethyl, or propyl moeity; and n and m are integers and are each independently between 1 and about 30. The solution is optically clear.

A crosslinking agent composition for water-compatible resins which comprises a hydrophobic crosslinking agent, a water-soluble organic compound, one or more oily media selected from among hydrocarbon-based solvents and ketone-based solvents having a solubility parameter of 9.0 (cal/cm.sup.3).sup.1/2 or less, and an aqueous medium. The crosslinking agent composition can improve the storage stability of a water-compatible resin composition. The water-compatible resin composition which contains this crosslinking agent composition can give cured objects satisfactory in terms of water resistance and solvent resistance and is suitable also for use in wet-on-wet coating.