Magnetic recording media comprising titanium monoxide and carbon black powders in a magnetic recording layer

DETAILED DESCRIPTION AND PREFERRED EMBODIMENTS OF THE INVENTION The magnetic recording media of the present invention have a magnetic recording layer formed on at least one side of a support.
The magnetic layer may be formed on one side or opposite sides of the support, depending on the type of medium.
The magnetic recording layer is made of a magnetic powder and a mixture of a TiO powder and a carbon black powder, all dispersed throughout a resin binder.
Any known magnetic materials can be used in the practice of the invention.
Examples of the magnetic materials include ferromagnetic iron oxide materials such as gamma-Fe.
sub.
2 O.
sub.
3 and Fe.
sub.
3 O.
sub.
4 with or without addition of other metals such as Co, Ni, Mn and the like, ferromagnetic metals such as Fe, Co, Ni and the like, and alloys thereof such as Fe-Co, Fe-Ni, Co-Ni Fe-Co-Ni with or without addition of other metals such as Al, Cr, Mn, Cu, Zn and the like.
In addition, other ferromagnetic materials such as CrO.
sub.
2 with or without other metals such as Al, Fe, Cu, Sn and the like may also be used.
These ferromagnetic materials are used in the form of particles or a powder having an average size of from 0.
05 to 5 microns.
It is essential in the practice of the invention to use the magnetic powder in combination with a mixture of TiO and carbon black powders.
TiO is usually obtained as black cubic crystals having a specific gravity of 4.
0 to 4.
9, a pH of about 7.
0 plus or minus 1.
0, and an electric resistance of 10.
sup.
-2 ohm-cm.
TiO is used in the form of a powder or particles having an average size of 0.
01 to 5 microns, preferably 0.
015 to 0.
2 micron, and is used in an amount of from about 0.
1 to 20 wt%, preferably about 3 to 10 wt%, of the magnetic powder or particles used.
Larger sizes are undesirable because magnetic heads and metal parts of a recording and reproducing apparatus are unfavorably abraded therewith.
Smaller sizes tend to lower a still reproduction characteristic.
The carbon black powder has generally an average size of from 10 to 50 millimicrons within which range the abrasion resistance, travelling performance, electromagnetic characteristics are improved with the light transmittance being effectively lowered when used in combination with the TiO powder having the above-defined range of the average size