| abstract |
NEW MATERIAL:An isocyanate compound of formula I. n EXAMPLE: Bis(4-isocyanatomethylthiophenyl)sulfide. n USE: A starting material for sulfur-contg. urethane resins of high refractive index. From this resin, lens with high refractive index can be obtained. n PREPARATION: For example, a reaction is made between 4,4'-thiobis-benzenethiol and ethyl chloroacetate in the presence of a base into a diester of formula II, which is then reacted with hydrazine into a hydrazide of formula III. This hydrazide is then reacted with sodium nitrite in the presence of hydrochloric acid into a diazide of formula IV, which is then heated to carry out Curtius rearrangement, thus obtaining the objective isocyanate compound of the formula I. Another objective sulfur-contg. resin can be obtained by reaction of the present isocyanate compound with at least one active hydrogen compound selected from polyols, polythiols and hydroxyl group-contg. mercapto compounds. n COPYRIGHT: (C)1992,JPO&Japio |