Fluorine-containing alkylsuccinic acid diester, process for preparing the same and use thereof
A magnetic recording medium comprising a lubricating layer comprising a fluorine-containing alkylsuccinic acid(cas:110-15-6) diester of the formula: ##STR1## wherein R1 is an aliphatic alkyl or alkenyl group, and one of R2 and R3 is a fluoroalkylether group and the other is a fluoroalkyl group, a fluoroalkenyl group, a fluorophenyl group, an aliphatic alkyl group or an aliphatic alkenyl group, which has excellent lubricity in an atmosphere having low to high humidity.
Example 4
This Example illustrates the production of a magnetic recording medium according to the present invention.
As a non-magnetic substrate, there was used a polyester film having gently sloped protrusions, which were formed by silica minute particles and had an average height of 70 ? and an average diameter of 1 μm, in a density of several protrusions per 100 μm2 and sharp protrusions formed from colloidal silica particles of 150 ? in diameter as nuclei and a UV curable epoxy resin as a binder in a density of 1×107protrusions per 1 mm2 but relatively large protrusions formed by a residue of polymerization catalyst as few as possible.
On a surface of non-magnetic substrate, a Co--Ni ferromagnetic metal film having a thickness of 1000 ? and a Ni content of 20% was formed in the presence of a very small amount of oxygen by a continuous inclined vapor deposition method. An oxygen content in the ferromagnetic metal layer was 5 atomic %.
On the surface of ferromagnetic metal film, the fluorine-containing alkylsuccinic acid(cas:110-15-6) diester of the formula (Ia) prepared in
Example 1 was coated in an amount of 10 mg/m2 to form a lubricating layer.
The film was then cut to a predetermined width to obtain a magnetic tape.
The magnetic tape was repeatedly run in a commercial video deck at 23° C., 10% RH or at 40° C., 80% RH, and output characteristics were measured. The number of runs was counted until the RF output decreased by 3 dB from the original RF output or until the output started to fluctuate.
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