Abstract:
Disclosed is a polythiourethane having high refractive index and low dispersibility which is obtained through a reaction between a polythiol component containing one or more polythiocarbonate polythiol (preferably one having a -(CO-S-R-S)- structure (wherein R represents a divalent hydrocarbon group) and a number average molecular weight of 200-2,500) and a polyisocyanate component containing a polyisocyanate and/or a polyisothiocyanate. This polythiourethane is useful for plastic lenses, prisms, optical fibers, substrates for information recording, colored filters, infrared absorbing filters and the like.
Abstract:
An optical material having high refractive index and toughness is obtained by curing a composition which contains (A) an episulfide compound, (B) an inorganic compound having a sulfur atom and/or a selenium atom, (C) an SH group-containing organic compound as an optional component, and (D) a polythiocarbonate dithiol represented by the following general formula (2). (2) (In the formula, R represents a divalent hydrocarbon group.)
Abstract:
A polyol mixture comprising 10 to 97 wt.% crystalline polyester polyol produced mainly from an aliphatic dicarboxylic acid and an aliphatic diol, 0 to 45 wt.% polyester polyol produced mainly from an aromatic polycarboxylic acid and an aliphatic polyol, and 3 to 45 wt.% polycarbonate polyol; a reactive hot-melt composition obtained by reacting this polyol mixture with a polyisocyanate; and a molded article obtained with this reactive hot-melt composition.