| 摘要 |
PURPOSE:To improve durability, running stability, magnetic characteristics, electromagnetic conversion characteristic, etc. by using a polyurethane resin having a siloxane bond in the molecular chain and having a ternary amine salt of a sulfonic acid as a polar group in the molecular side chain for a binder constituting a magnetic layer. CONSTITUTION:The magnetic layer contains the polyurethane resin having the siloxane bond in the molecular chain and having the ternary amine salt of the sulfonic acid as the polar group in the molecular side chain as the binder. The polyurethane resin is obtd. by the reaction of a polyhydroxy compd. and polyisocyanate. A long chain diol having about 500-5,000mol.wt. and short chain diol having about 50-500mol.wt. are preferably used for the polyhydroxy compd. An org. diisocyanate is preferably used for the polyisocyanate. Such polyurethane resin exhibits high affinity to magnetic powder and lubricity and has excellent running stability. |
