The modified polycarbodiimide compound of the present invention is obtained by modifying a polycarbodiimide compound derived from a diisocyanate compound with at least one aliphatic amine selected from the group consisting of diethylamine, methylisopropylamine, tert-butylethylamine, di-sec-butylamine, dicyclohexylamine, 2-methylpiperidine and 2,6-dimethylpiperidine. The curing agent of the present invention comprises the modified polycarbodiimide compound of the present invention. The thermosetting resin composition of the present invention comprises a carboxyl group-containing resin having a carboxyl group in a molecule or an epoxy resin having two or more epoxy groups in one molecule, and the curing agent of the present invention. Thus, a modified polycarbodiimide compound that can allow a resin composition to be cured at a relatively low temperature and that can suppress curing of a resin composition in a drying step before a thermal curing step of a resin composition, a curing agent comprising the modified polycarbodiimide compound, and a thermosetting resin composition comprising the curing agent can be provided.

The modified polycarbodiimide compound of the present invention is obtained by modifying a polycarbodiimide compound derived from a diisocyanate compound with an aromatic heterocyclic compound having endocyclic secondary amine nitrogen. The curing agent of the present invention comprises the modified polycarbodiimide compound of the present invention. Thus, a modified polycarbodiimide compound that allows amine dissociation to start at a low temperature as compared with a modified polycarbodiimide compound obtained by modifying a polycarbodiimide compound derived from a diisocyanate compound with diisopropylamine, and a curing agent comprising the modified polycarbodiimide compound can be provided.

Disclosed is a method for preparing powder coating compositions. The method includes mixing in an aqueous medium a carboxylic acid functional polymer having a high glass transition temperature, with a polycarbodiimide having a high glass transition temperature, drying the mixture, and grinding the resulting solid particles to obtain a powder.

A fluorine-free composition includes at least one polycarbodiimide compound derived from a carbodiimidization reaction of a carbodiimidization reaction mixture comprising at least one oligomer, wherein the oligomer comprises at least one isocyanate end group and at least two repeating units, wherein each of the at least two repeating units comprises at least one hydrocarbon group having at least 16 carbon atoms. The composition may also include at least one paraffin wax. Such compositions are useful for treating fibrous substrates to enhance their water-repellency.

Provided is a carbodiimide-based, waterborne resin crosslinking agent that can improve the storage stability of a waterborne resin composition including a waterborne resin together with the crosslinking agent and further also improve the water resistance and the solvent resistance of a cured product of the waterborne resin. A waterborne resin crosslinking agent-containing liquid and a waterborne resin composition are prepared using a waterborne resin crosslinking agent comprising a hydrophobic polycarbodiimide compound and a water-soluble organic compound as blending components, wherein the water-soluble organic compound is one or more selected from the group consisting of an alkylene glycol-based compound, a water-soluble polymer other than the alkylene glycol-based compound, and a surfactant other than the alkylene glycol-based compound or the water-soluble polymer.

A waterborne resin crosslinking agent containing a predetermined polycarbodiimide compound (A) having an oxyalkylene group, a predetermined polycarbodiimide compound (B), and a surfactant (C), each polycarbodiimide compound has a structure in which an isocyanate group is capped with a predetermined end-capping compound at each of both terminals, a total content of the oxyalkylene group in (A) is 15% by mass or more, a total content of the oxyalkylene group in (A) and (B) based on a total amount of (A) and (B) is 10% by mass or less, and a content of (C) is 0.1 to 20 parts by mass based on a total content of (A) and (B) of 100 parts by mass.

A method of producing a polycarbodiimide polymer comprises heating a precursor compound at a desired temperature. The method further comprises combining the precursor compound, a diisocyanate compound, and a carbodiimidization catalyst to form a reaction mixture. Finally, the method comprises heating the reaction mixture for a first period of time at a first temperature, thereby reacting the precursor compound and the diisocyanate compound in the presence of the carbodiimidization catalyst to produce the polycarbodiimide polymer.

Disclosed are polycarbodiimides having onium salt groups, as well as methods for their production.

The present invention relates to novel processes for producing bis[3-isopropenyl-,-dimethylbenzyl]carbodiimide, to the thus-produced bis[3-isopropenyl-,-dimethylbenzyl]carbodiimide and to the use thereof as a hydrolysis inhibitor in polyurethane (PU)-based systems, preferably thermoplastic TPU, PU adhesives, PU casting resins, PU elastomers or PU foams.

A process of preparing a post-modified polycarbodiimide, the process includes combining a diisocyanate, a moisture scavenger, a monoisocyanate, and a catalyst in a reaction vessel; and heating the reaction vessel to a temperature and a time sufficient to form a capped polycarbodiimide wherein the capped polycarbodiimide has 0.25 wt % or less of free isocyanate groups; and the combining and heating are conducted in the absence of a solvent.