PURPOSE: To obtain a highly stable solution of a high-molecular-weight polycarbodiimide by polymerizing an organic diisocyanate in the presence of a carbodiimidation catalyst in a chlorinated aromatic compound solvent.
CONSTITUTION: The obtained polycarbodiimide should have a controlled number- average molecular weight of 5,000-60,000. An example of the organic diisocyanate used is 2,4-tolylene diisocyanate. An example of the carbodiimidation catalyst is 1-phenyl-2-phospholene-1-oxide. The solvent used is a chlorinated aromatic compound of a boiling point of 120°C or above (e.g. chlorobenzene). From the viewpoint of moldability, the concentration of the organic diisocyanate is 1-20w/w% based on the solvent. Desirably, the amount of the catalyst used is 0.05-0.2mol%, and the reaction temperature is 100-150°C. Although the reaction can be accomplished within 1-4hr under these reaction conditions,they are not limitative. To measure the number-average molecular weight, gel permeation chromatography can be desirably used.
TAKIGUCHI YASUYUKI
HACHIMAN TAKESHI
HAYASHIDA AKIRA
TAKAMIZAWA MINORU
