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AssigneeWD Media (Singapore) Pte. Ltd.
InventorsKatsushi Hamakubo, Koichi Shimokawa, Kota Suzuki
Estimating the term…
A lubricant for magnetic disks which can form a lubricating layer having a reduced thickness while attaining a high coverage and is excellent in heat resistance and adhesion to a protective layer. The lubricant for magnetic disks comprises a perfluoropolyether compound in which the relationship between the number-average molecular weight and the standardized value of the number of hydroxy groups contained in the molecule satisfies the following: the number-average molecular weight is in the range of 1,000-6,000; the standardized value of the number of hydroxy groups contained in the molecule is 180 or higher; and the compound is in a region located below the line connecting the point where the number-average molecular weight is 1,000 and the standardized value of the number of hydroxy groups in the molecule is 400 to the point where the number-average molecular weight is 6,000 and the standardized value of the number of hydroxy groups in the molecule is 1,600. The compound has at least one hydroxy group around the center of the molecular chain.
A lubricant for a magnetic disk, said lubricant containing a perfluoropolyether-based compound in which perfluoropolyether groups are bonded to each other through a divalent linking group having at least one hydroxyl group such that the perfluoropolyether-based compound has at least one hydroxyl group around a center of a molecular chain, the perfluoropolyether-based compound having a number-average molecular weight in the range of 1000 to 6000 and a normalized value of the number of hydroxyl groups contained in a molecule in the range of 180 to 1600.
Dependencies are inferred from the claim text.