LEPIDOCROCITE PARTICLE POWDER FOR NON-MAGNETIC PRIMER LAYER OF MAGNETIC RECORDING MEDIUM, SUBSTRATE OF MAGNETIC RECORDING MEDIUM HAVING NON-MAGNETIC PRIMER LAYER USING THE LEPIDOCROCITE PARTICLE POWDER, AND MAGNETIC RECORDING MEDIUM USING THE SUBSTRATE

摘要

PROBLEM TO BE SOLVED: To obtain a non-magnetic particle powder excellent in surface smoothness and suitable for non-magnetic primer coating layers, by forming repidocrocite particles into a hexahedral shape having a specific minor axis diameter, a specific major axis diameter and a specific thickness and subsequently coating the surfaces of the particles with the hydroxide or oxide of Al, Si, etc. ;SOLUTION: This repidocrocite particle powder for the non-magnetic primer layers of magnetic recording media comprises hexahedral repidocrocite particles having a minor axis diameter of 0.045-0.5m, a major axis diameter of 0.05-1.0m and a thickness of 0.01-0.3m. The surfaces of the particles are preferably coated with the hydroxide or oxide of Al or the hydroxide or oxide of Si. The non-magnetic particle powder is suitably used for non- magnetic primer layers formed on non-magnetic supports in order to obtain substrates having large strengths. The non-magnetic primer layers on the substrates of the magnetic recording media area formed by coating the non-magnetic supports with a coating composition comprising a binder resin and the non-magnetic particle powder comprising the repidocrocite particle powder.;COPYRIGHT: (C)1998,JPO