| 摘要 |
PURPOSE:To obtain a magnetic tape having stable sound quality and image quality by using a polyurethane resin consisting of an active hydrogen-contg. compd. component consisting of a specific high-polymer polyol, low-polymer polyol and compd. having a carboxyl group and active hydrogen-contg. group and an org. polyisocyanate. CONSTITUTION:This magnetic tape consists of the polyurethane resin (the mol.wt. per carboxyl group is larger than 50,000 and up to 20,000) consisting of the active hydrogen-contg. compd. component consisting of the high-polymer polyol of 200-2,000 equiv. contg. a cyclic dicarboxylic acid modified polycaprolactone polyol, low-polymer polyol and the compd. having the carboxyl group and other active hydrogen-contg. groups in the molecule and the org. polyisocyanate. The dispersibility of the magnetic powder of the resultant urethane resin is low and the scratching resistance is low if the equiv. of the high- polymer polyol is <200. The dispersibility of the resultant polyurethane resin, and the resistance thereof to wear, scratching and hydrolysis are low if the equiv. exceeds 2,000.
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