Polycarbodiimide composition, method for producing polycarbodiimide composition, aqueous dispersion composition, solution composition, resin composition, and cured resin

A polycarbodiimide composition comprising:

• a reaction product of polyisocyanate having a primary isocyanate group and alcohols,
• wherein the polycarbodiimide composition includes a carbodiimide group and a uretonimine group,
• in an infrared absorption spectrum, the intensity ratio (IRCI/IRUI+U) of absorbance IRCI at or near 2120 cm−1 due to stretching vibration of the carbodiimide group relative to absorbance IRUI+U at or near 1720 cm−1 due to stretching vibration of the uretonimine group and urethane group is 1.5 or more and 4.5 or less, and
• the equivalent ratio (NCO/OH) of the isocyanate group of polyisocyanate relative to the hydroxyl group of the alcohols is more than 2 and 16 or less.