PURPOSE: To improve the dispersibility of magnetic powder, etc. and to obtain a magnetic recording medium having excellent durability, etc. by inorporating a specific polyurethane resin, phenoxy resin and low mol.wt. isocyanate compd. as a binder component into a magnetic layer.
CONSTITUTION: The magnetic paint contg. the polyurethane resin which is obtd. from a mixture composed of butyrene adipate and tertiary alcohol and 4,4'- diphenyl methane diisocyanate, has tertiary OH in the position except both terminals of the principal chain and has 20,000W30,000 average mol.wt., phenoxy resin and low mol.wt. isocyanate compd., necessary dispersant, lubricating agent, carbon black as an antistatic agent, Al2O3 as a polishing agent, etc. is prepd. Such paint is coated on a non-magnetic substrate consisting of polyester, polyimide, etc. and is cured to manufacture the magnetic recording medium. The magnetic recording medium which has the good dispersibility of the magnetic powder, carbon black, polishing material, etc., has small modulation and excellent electromagnetic conversion characteristic and maintains the excellent durability even in severe environment such as high temp., high humidity, low temp. and low humidity is thus obtd.
INABE TOSHIHISA
ANDO TAKASHI
HAJI YUJI
SATO HIROMI
