Wd Media (singapore) Pte. Ltd.

Wd Media, LLC

(singapore) Pte. Ltd.

Kae Itoh

Katsushi Hamakubo

Koichi Shimokawa

Kota Suzuki

A magnetic disk of is provided, the magnetic disk having at least a magnetic layer, a carbon protective layer, and a lubrication layer sequentially provided on a substrate. In an embodiment, the lubrication layer a film formed by a lubricant having a perfluoropolyether compound A having a perfluoropolyether main chain in the structure and also having a hydroxyl group at the end and a compound C obtained from a reaction between a compound B expressed by: [Chemical formula 1] CF(&#x2014;O&#x2014;CF)m-(O&#x2014;CF)n-OCF[m and n in the formula are natural numbers.] and aluminum oxide.

Magnetic disk and manufacturing method thereof

A lubricant compound is contained in a lubrication layer of a magnetic disk in which at least a magnetic layer, a protective layer, and a lubrication layer are sequentially provided on a substrate, and the lubricant compound contains a component A represented by Chemical formula 1 and a component B represented by Chemical formula 2: wherein X in Chemical formula 1 represents OH wherein X in Chemical formula 2 represents OCHCH(OH)CHOH,and the lubricant compound further contains a component C made of a specific compound having a phosphezene ring in the structure thereof.

Lubricant compound for magnetic disk and magnetic disk

Disclosed is a magnetic disk that has excellent durability, particularly excellent LUL durability, and excellent alumina resistance and has a high level of reliability under a low flying height of a magnetic head involved in a recent tendency toward a rapid increase in recording density and a very severe environment resistance requirement due to diversified applications. A magnetic disk () comprises a substrate () and at least a magnetic layer (), a carbon-based protective layer (), and a lubricating layer () provided in that order over the substrate (). The lubricating layer () contains a compound that has a perfluoropolyether main chain in the structure thereof and has an aromatic group and a polar group at the end of the molecule.

Magnetic disk and method of manufacturing the same

A magnetic disk having at least a magnetic layer, a carbon protective layer, and a lubrication layer sequentially provided on a substrate. The lubrication layer is a film formed by a lubricant that contains two types of compounds having a perfluoropolyether main chain in the structure, a molecular weight distribution of the two types in total being within a range of 1 to 1.2. The two types of compounds include a compound a having a hydroxyl group at the end and a compound b having a number average molecular weight smaller than the number average molecular weight of the compound a and not more than 1500. A content of the compound b in the two types of compounds is not more than 10%.

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 () has at least a magnetic layer (), a carbon-based protective layer (), and a lubricating layer () provided in this order over a substrate (). The lubricating layer () 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.

A method of manufacturing a magnetic disk in which at least a magnetic layer, a carbon protective layer, and a lubrication layer are sequentially formed on a substrate is provided. The method comprises forming a film of a lubricant composition on the protective layer, the lubricant comprising a lubricant compound having a perfluoropolyether main chain in the molecular structure and an aromatic group or a phosphazene ring. The method further comprises forming the lubrication layer, and subjecting the magnetic disk to ultraviolet irradiation under a nitrogen gas or an inert gas atmosphere having an oxygen concentration of 5 volume % or less by adjusting an atmospheric temperature to a range of 50 to 180&#xb0; C.

Method of producing a magnetic recording disc

On manufacturing a magnetic disk having at least a magnetic layer (), a protective layer (), and a lubricating layer () formed in this order over a substrate (), the lubricating layer is formed by using a coating solution in which a perfluoropolyether compound having a perfluoropolyether main chain and a hydroxyl group in a structure thereof is dispersed and dissolved in a fluorine-based solvent having a boiling point of 90&#xb0; C. or more.

Method of manufacturing a magnetic disk

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&#x2014;CH(OH)&#x2014;CH&#x2014;CH&#x2014;CH(OH)&#x2014;CH-0-or-0-CH&#x2014;CH(OH)&#x2014;CH(OH)&#x2014;CH-0-.

Lubricant for magnetic disc, magnetic disc and method of producing the same

In a magnetic disk that has at least a magnetic layer, a carbon-based protective layer, and a lubricating layer formed in this order over a substrate, the lubricating layer contains a lubricant compound including a compound which has a perfluoropolyether main chain in a structure thereof, an aromatic group located at a position except each end of a molecule thereof, and a polar group at each end of the molecule.

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Tokyo, Japan

Kae Itoh