| 摘要 |
PURPOSE:To obtain a recording medium having improved running durability and low deterioration in electromagnetic conversion characteristic by providing a back layer of specific average centerline hardness (Ra) contg. carbon black, graphite and talc on the base surface of a magnetic recording medium opposite to the magnetic layer thereof. CONSTITUTION:A back layer is formed on the surface of a magnetic recording medium opposite to the magnetic layer thereof by using a mixture contg. the three components; carbon black having 0.05-0.15mu average primary particle size, graphite having <=10mu average primary particle size and talc having <=10mu average primary particle size at 10:1-1:10 weight ratio between the carbon black and the graphite and contg. the talc powder at 5:95-95:5 by the total weight of the carbon black and the graphite with polyisocyanate, epoxy resin, etc. as a hardener. The magnetic medium of which the back layer has <=0.035mu surface roughness Ra, and which has excellent running durability, obviates generation of stripping powder, etc., prevents the transfer of the ruggedness on the back layer to the magnetic layer and has a particularly excellent video S/N ratio is thus obtd. |
