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US 7,247,397 B2Granted
Thermally stable perfluoropolyether lubricant for recording media
AssigneeImation Corp.
InventorRamon F. Hegel
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AssigneeImation Corp.
InventorRamon F. Hegel
Estimating the term…
The invention provides a lubricant useful in magnetic recording media and optical recording media comprising a functionalized perfluoropolyether comprising multiple acrylate endgroups. More specifically, the lubricant of the invention is a functionalized perfluoropolyether comprising at least about two acrylate groups. In one embodiment, the lubricant of the invention is a functionalized perfluoropolyether comprising a perfluoropolyether tetraacrylate. A magnetic recording medium is also provided comprising a thin metal magnetic recording layer, said layer having a coating of the functionalized perfluoropolyether lubricant comprising at least about three acrylate end groups. An optical recording medium including the functionalized perfluoropolyether lubricant includes at least one magneto-optical layer disposed between two protective layers further disposed between two substrate layers having interior and exterior surfaces, the exterior surface of at least one substrate layer bearing thereon a functionalized perfluoropolyether lubricant comprising a perfluoropolyether tetraacrylate.
An optical recording medium comprising at least one thin film of magneto-optical material disposed between two protective layers, wherein the surface of said optical recording medium has a lubricant deposited thereon, wherein said lubricant is a functionalized perfluoropolyether tetraacrylate having a molecular weight of from about 2000 to about 3000.
A magnetic recording medium comprising at least one thin film of magneto-optical material disposed between two protective layers, wherein the surface of said optical recording medium has a lubricant deposited thereon, wherein said lubricant is a functionalized perfluoropolyether lubricant comprising a perfluoropolyether tetraacrylate having the formula
A magnetic recording medium comprising at least one thin metal recording layer, said layer having a lubricant deposited thereon, wherein said lubricant is a functionalized perfluoropolyether tetraacrylate having a molecular weight of from about 2000 to about 3000.
A magnetic recording medium comprising at least one thin metal recording layer, said layer having a lubricant deposited thereon wherein said lubricant is a functionalized perfluoropolyether lubricant comprising a perfluoropolyether tetraacrylate having the formula
Dependencies are inferred from the claim text.
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From the US filing history. Foreign family members aren’t listed.
Record carriers characterised by the selection of the material or by the structure or form: characterised by the form, e.g. comprising mechanical…
Containing halogen: containing carbon, hydrogen, halogen and oxygen
Containing carbon, hydrogen, halogen and oxygen: acids; Salts or esters thereof
On a base layer: characterised by the lubricant
Term ended 3 Jul 2025 (estimated)
The present invention relates generally to a perfluoropolyether lubricant material, and specifically to a thermally stable lubricating material which is useful in magnetic recording media such as magnetic tape, and in optical recording media, and the media employing such a lubricant.
Magnetic recording media are widely used in audio tapes, video tapes, computer tapes, disks and the like. Magnetic media may use thin metal layers as the recording layers, or may comprise coatings containing magnetic particles as the recording layer. The former type of recording media employs metals such as cobalt, cobalt chrome, cobalt nickel, cobalt chrome platinum, and other cobalt alloys. The latter type of recording media employs particulate materials such as ferromagnetic iron oxides, chromium oxides, ferromagnetic alloy powders and the like dispersed in binders and coated on a substrate. In general terms, magnetic recording media generally comprise a magnetic layer coated onto at least one side of a non-magnetic substrate.
In media based on a thin metallic magnetic recording layer, such as a magnetic cobalt alloy, the overall media construction will generally include several thin films coated in sequence which form a “thin film stack.” The first thin film stack layers coated generally function to provide a combination of adhesion, topographical texture, and crystalline texture. These layers are then followed by one or more magnetic thin films which do the actual information storage. The magnetic thin films are followed by one or more coatings which provide environmental stability, hardness, and compatibility with the subsequently coated lube. The lube layer constitutes the final layer of the thin film media.
The following detailed description describes certain embodiments and is not to be taken in a limiting sense. The scope of the present invention is defined by the appended claims.
The lubricant comprises a functionalized perfluoropolyether comprising at least a perfluoropolyether diacrylate.
The magnetic recording medium includes a thin metal magnetic recording layer and at least one thin film layer not having an information recording function.