PURPOSE: To obtain a titled resin having a high modulus of elasticity and mechanical strength and the excellent smoothness, the moisture and heat resistance of the surface of the magnetic powder dispersible magnetic coated film by bringing a polyisocyanate compd. and specific polyhydroxy compd. into reaction.
CONSTITUTION: A prepolymer having an isocyanate group at the terminal is produced by bringing the polyhydroxy compd. having active hydrogen and the stoichiometrically excessive polyisocyanate compd. into reaction in a 10W150°C temp. range by using, for example, a solvent usually inert with the isocyanate group according to need and using a catalyst for urethanation. The polyurethane resin having a hydroxyl group at the terminal is then obtd. by bringing a diol, diamine or triol which is a chain extender into reaction therewith. The compd. contg. ≥10wt% polycaprolactone polyol of 500W5,000 number average mol.wt. obtd. by the ring opening polymn. of -caprolactone with β- oxyethyl terephthalate as an initiator glycol is used as the polyhydroxy compd. having ≥2 active hydrogen in the molecule.
TANIGUCHI YASUYUKI
IIZUKA HARUO
