| abstract |
PURPOSE: The titled resin providing lens having high refractive index, having improved cutting properties, and processing properties of sanding, obtained by reacting a bi- or more functional polyisocyanate with a polyol containing S in a specific ratio. in a specified ratio of both the components. n CONSTITUTION: (A) A bi- or more functional polyisocyanate (e.g., hexamethylenediisocyanate, etc.) is blended with (B) a polyol containing ≥20wt%, preferably 25W40wt% S [e.g., di(2-hydroxyethyl)sulfide, etc.], and, if necessary, (C) a polyol containing no S in a molar ratio of NCO/OH of 0.5W1.5, and reacted by cast molding method, etc. usually at -20W80°C for 24W72hr while carrying out sufficient removal of heat and temperature control, to give the desired resin. n COPYRIGHT: (C)1985,JPO&Japio |