Lubricant for magnetic disc, magnetic disc and method of producing the same
View Patent ↗A magnetic disk in which at least a magnetic layer, a protective layer, and the lubrication layer are sequentially provided on a substrate, the lubrication layer contains a lubricant compound for a magnetic disk, having a perfluoropolyether main chain in the molecular structure and a structure indicated as follows at a position close to the center of the molecule: -0-CH 2 —CH(OH)—CH 2 —CH 2 —CH(OH)—CH 2 -0- or -0-CH 2 —CH(OH)—CH(OH)—CH 2 -0-.
1. A lubricant compound for a magnetic disk, the lubricant compound being contained in a lubrication layer of the magnetic disk in which at least a magnetic layer, a protective layer, and the lubrication layer are sequentially provided on a substrate, the lubricant compound represented by one of the following formulas:
HOCH 2 CF 2 (Rf)OCF 2 CH 2 OCH 2 CH(OH)CH 2 CH 2 CH(OH)CH 2 O—*
*—CH 2 CF 2 (Rf)OCF 2 CH 2 OH [Formula 1]
HOCH 2 CH(OH)CH 2 OCH 2 CF 2 (Rf)OCF 2 CH 2 OCH 2 CH(OH)CH 2 CH 2 —*
*—CH(OH)CH 2 OCH 2 CF 2 (Rf)OCF 2 CH 2 OCH 2 CH(OH)CH 2 OH [Formula 2]
HOCH 2 CH(OH)CH 2 OCH 2 CH(OH)CH 2 OCH 2 CF 2 (Rf)0-*
*—CF 2 CH 2 OCH 2 CH(OH)CH 2 CH 2 CH(OH)CH 2 OCH 2 CF 2 (Rf)0-**
**—CF 2 CH 2 OCH 2 CH(OH)CH 2 OCH 2 CH(OH)CH 2 OH [Formula 3]
HOCH 2 CF 2 (Rf)OCF 2 CH 2 OCH 2 CH(OH)CH(OH)CH 2 O—*
*—CH 2 CF 2 (Rf)OCF 2 CH 2 OH [Formula 4]
HOCH 2 CH(OH)CH 2 OCH 2 CF 2 (Rf)OCF 2 CH 2 OCH 2 CH(OH)—*
*—CH(OH)CH 2 OCH 2 CF 2 (Rf)OCF 2 CH 2 OCH 2 CH(OH)CH 2 OH [Formula 5]
HOCH 2 CH(OH)CH 2 OCH 2 CH(OH)CH 2 OCH 2 CF 2 (Rf)0-*
*—CF 2 CH 2 OCH 2 CH(OH)CH(OH)CH 2 OCH 2 CF 2 (Rf)0-**
**—CF 2 CH 2 OCH 2 CH(OH)CH 2 OCH 2 CH(OH)CH 2 OH [Formula 6]
wherein Rf represents —(OC 2 F 4 )m(OFC 2 )n— and m and n each represent an integer that is not less than 1.
2. The lubricant compound for a magnetic disk according to claim 1 , wherein the number average molecular weight of the lubricant compound is within a range of 1000 to 4000.
3. A magnetic disk in which at least a magnetic layer, a protective layer, and a lubrication layer are sequentially provided on a substrate, characterized in that the lubrication layer contains the lubricant compound for a magnetic disk according to claim 1 .
4. The magnetic disk according to claim 3 , wherein the protective layer is a film of a carbon protective layer formed by a plasma CVD method.
5. The magnetic disk according to claim 4 , wherein the protective layer contains nitrogen on the side in contact with the lubrication layer.
6. The magnetic disk according to claim 1 , wherein the magnetic disk is mounted on a magnetic disk device whose start/stop mechanism is of a load-unload type.
7. A manufacturing method of a magnetic disk in which at least a magnetic layer, a protective layer, and a lubrication layer are sequentially provided on a substrate, characterized in that the lubrication layer is formed by forming a film of a lubricant composition containing the lubricant compound for a magnetic disk according to claim 1 on the protective layer.
8. The manufacturing method of a magnetic disk according to claim 7 , wherein after a film of the lubrication layer is formed, heating treatment is applied to the magnetic disk.