Magnetic disk and method of manufacturing the same
View Patent ↗Provided is a magnetic disk that is excellent in durability, particularly in LUL durability and CFT properties, and thus has high reliability despite the low flying height of a magnetic head following the rapid increase in recording density in recent years and despite the very strict environmental resistance following the diversification of applications. A magnetic disk ( 10 ) has at least a magnetic layer ( 6 ), a carbon-based protective layer ( 7 ), and a lubricating layer ( 8 ) provided in this order over a substrate ( 1 ). The lubricating layer ( 8 ) contains a compound having a perfluoropolyether main chain in a structure thereof and having a polar group other than at ends of a molecule thereof.
1. A magnetic disk comprising:
a substrate, and
a magnetic layer, a protective layer, and a lubricating layer provided in this order over the substrate,
wherein said lubricating layer contains a compound having a perfluoropolyether main chain in a structure thereof and having at least three hydroxyl groups other than at ends of a molecule thereof, and wherein the ends of the molecule of the compound do not contain polar groups such that the ends are in a free state,
wherein the compound having a perfluoropolyether main chain is obtained by reacting a perfluorodiol compound represented by the following formula (II) and a diepoxy compound:
CF 3 CF 2 (OC 2 F 4 ) m (OCF 2 ) n OCF 2 CH 2 OH formula (II)
wherein m and n are each an integer of 1 or more, and
wherein the diepoxy compound is represented by one of the following formulas:
2. A magnetic disk according to claim 1 , wherein a number-average molecular weight of said compound contained in said lubricating layer is in a range of 1000 to 10000.
3. A magnetic disk according to claim 1 , wherein said protective layer is a carbon-based protective layer formed by a plasma CVD method.
4. A magnetic disk according to claim 1 , wherein said magnetic disk is adapted to be mounted in a magnetic disk device of a load unload system.
5. A magnetic disk according to claim 2 , wherein said protective layer is a carbon-based protective layer formed by a plasma CVD method.
6. A magnetic disk according to claim 2 , wherein said magnetic disk is adapted to be mounted in a magnetic disk device of a load unload system.
7. A magnetic disk according to claim 3 , wherein said magnetic disk is adapted to be mounted in a magnetic disk device of a load unload system.
8. A magnetic disk according to claim 1 , wherein the diepoxy compound is represented by the following formula:
9. A magnetic disk according to claim 1 , wherein the diepoxy compound is represented by the following formula:
10. A magnetic disk according to claim 1 , wherein the diepoxy compound is represented by the following formula:
11. A magnetic disk according to claim 1 , wherein the diepoxy compound is represented by the following formula: