BINDER FOR MAGNETIC RECORDING MEDIUM AND MAGNETIC RECORDING MEDIUM

• Main Authors: OKADA TOMOYUKI, TSUSHIMA RIKIO, YAMASHITA KAZUTAKA, KANNEN NAOKI
• Format: Patent
• Language: English
• Published: 13.02.1987
• Subjects: ADHESIVES; CHEMICAL PAINT OR INK REMOVERS; CHEMISTRY; COATING COMPOSITIONS, e.g. PAINTS, VARNISHES ORLACQUERS; CORRECTING FLUIDS; DYES; FILLING PASTES; INFORMATION STORAGE; INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORDCARRIER AND TRANSDUCER; INKS; METALLURGY; MISCELLANEOUS APPLICATIONS OF MATERIALS; MISCELLANEOUS COMPOSITIONS; NATURAL RESINS; PAINTS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; PHYSICS; POLISHES; USE OF MATERIALS THEREFOR; WOODSTAINS

PURPOSE:To improve the dispersibility of magnetic powder, surface smoothness and durability by consisting a binder of a polyurethane resin produced by using a specific lactone-modified diol. CONSTITUTION:The binder for magnetic recording consisting of the polyurethane resin produced by using the lactone-modified diol expressed by the formula is used. A magnetic layer constituted by dispersing ferromagnetic powder into such binder is provided on a nonmagnetic base. The lactone-modified diol to be used as the binder has preferably the number average mol.wt. ranging 400-60,000 in terms of the flexibility of the resulted polyurethane resin and the toughness of the resin. The ratio of the binder and the pulverous ferromagnetic powder is preferably in a 10-100pts.wt. binder range with 100pts. pulverous ferromagnetic powder. The pulverous ferromagnetic powder is exemplified by gamma-Fe2O3, mixed crystals or gamma-Fe2O3 and Fe3O4, Co-modified iron oxide, CrO.2, iron, etc. The dispersibility and durability are thereby extremely improved.