Method of producing a lubricant for a magnetic disk, lubricant for a magnetic disk, magnetic disk, and method of producing a magnetic disk
View Patent ↗On producing a lubricant which is used in making a lubrication layer included in a magnetic disk from the lubricant, a phosphorus-containing compound is removed from a raw-material lubricant including the phosphorus-containing compound to produce the lubricant. The magnetic disk includes a substrate on which at least a magnetic layer, a protection layer, and the lubrication layer formed by the use of the lubricant are successively formed.
1. A method of producing a lubricant for a magnetic disk including a lubrication layer, said lubricant being used in making said lubrication layer from said lubricant, said method comprising a removing step of removing, from a raw-material lubricant including a phosphorus-containing compound, said phosphorus-containing compound to produce said lubricant,
wherein said removing step is for removing, from said raw-material lubricant, said phosphorus-containing compound by bringing said raw-material lubricant into contact with a molecular sieve, and
wherein said molecular sieve is crystalline zeolite having an effective pore size of 0.3 to 1.0 nm.
2. The method according to claim 1 , wherein said removing step produces said lubricant which includes the phosphorus-containing compound of 0.01 μg/g or less in terms of phosphate ions (PO 4 3− ).
3. The method according to claim 1 , wherein said removing step is for removing, from said raw-material lubricant, said phosphorus-containing compound by bringing said raw-material lubricant into contact with a molecular sieve and, subsequently, subjecting said raw-material lubricant to molecular distillation.
4. The method according to claim 2 , wherein said removing step is for removing, from said raw-material lubricant, said phosphorus-containing compound by bringing said raw-material lubricant into contact with a molecular sieve and, subsequently, subjecting said raw-material lubricant to molecular distillation.
5. A method of producing a lubricant for a magnetic disk including a lubrication layer, said lubricant being used in making said lubrication layer from said lubricant, said method comprising a removing step of removing, from a raw-material lubricant including a phosphorus-containing compound, said phosphorus-containing compound to produce said lubricant,
wherein said removing step is for removing, from said raw-material lubricant, said phosphorus-containing compound by bringing said raw-material lubricant into contact with a molecular sieve, and
wherein said raw-material lubricant further includes a fluoropolyether compound having four hydroxyl groups in one molecule.
6. A method of producing a lubricant for a magnetic disk including a lubrication layer, said lubricant being used in making said lubrication layer from said lubricant, said method comprising a removing step of removing, from a raw-material lubricant including a phosphorus-containing compound, said phosphorus-containing compound to produce said lubricant,
wherein said removing step is for removing, from said raw-material lubricant, said phosphorus-containing compound by bringing said raw-material lubricant into contact with a molecular sieve,
wherein said molecular sieve is crystalline zeolite having an effective pore size of 0.3 to 1.0 nm, and
wherein said raw-material lubricant further includes a fluoropolyether compound having four hydroxyl groups in one molecule.
7. A method of producing a lubricant for a magnetic disk including a lubrication layer, said lubricant being used in making said lubrication layer from said lubricant, said method comprising a removing step of removing, from a raw-material lubricant including a phosphorus-containing compound, said phosphorus-containing compound to produce said lubricant,
wherein said removing step is for removing, from said raw-material lubricant, said phosphorus-containing compound by bringing said raw-material lubricant into contact with a molecular sieve and, subsequently, subjecting said raw-material lubricant to molecular distillation, and
wherein said raw-material lubricant further includes a fluoropolyether compound having four hydroxyl groups in one molecule.
8. A method of producing a lubricant for a magnetic disk including a lubrication layer, said lubricant being used in making said lubrication layer from said lubricant, said method comprising a removing step of removing, from a raw-material lubricant including a phosphorus-containing compound, said phosphorus-containing compound to produce said lubricant,
wherein said removing step is for removing, from said raw-material lubricant, said phosphorus-containing compound by bringing said raw-material lubricant into contact with a molecular sieve and, subsequently, subjecting said raw-material lubricant to molecular distillation,
wherein said molecular sieve is crystalline zeolite having an effective pore size of 0.3 to 1.0 nm, and
wherein said raw-material lubricant further includes a fluoropolyether compound having four hydroxyl groups in one molecule.
9. The method according to claim 5 , wherein said removing step produces said lubricant which includes the phosphorus-containing compound of 0.01 μg/g or less in terms of phosphate ions (PO 4 3− ).
10. The method according to claim 6 , wherein said removing step produces said lubricant which includes the phosphorus-containing compound of 0.01 μg/g or less in terms of phosphate ions (PO 4 3− ).
11. The method according to claim 7 , wherein said removing step produces said lubricant which includes the phosphorus-containing compound of 0.01 μg/g or less in terms of phosphate ions (PO 4 3− ).
12. The method according to claim 8 , wherein said removing step produces said lubricant which includes the phosphorus-containing compound of 0.01 μg/g or less in terms of phosphate ions (PO 4 3− ).