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

{
  "publication_number": "US2012148875A1",
  "country": "US",
  "kind": "A1",
  "title": "Lubricant for magnetic disc, magnetic disc and method of producing the same",
  "abstract": "A magnetic disk with which further reduction of magnetic spacing can be realized and which has high reliability under such circumstances of a lower floating amount of a magnetic head involved in the recent rapid increase in recording density and of extremely severe environmental resistance involved in diversification in use applications is provided. In 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 2 - CH(OH) - CH 2 - CH 2 - CH(OH) - CH 2 -0- or -0-CH 2 - CH(OH) - CH(OH) - CH 2 -0-",
  "claims": [
    "1. A lubricant compound for a magnetic disk, the lubricant compound being contained in a lubrication layer of the magnetic disk in which at least a magnetic layer, a protective layer, and the lubrication layer are sequentially provided on a substrate, comprising: 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 2 - CH(OH)-CH 2 - CH 2 - CH(OH) - CH 2 -0- or -0-CH 2 - CH(OH) - CH(OH) - CH 2 -0- 2. The lubricant compound for a magnetic disk according to claim 1, further comprising: a hydroxyl group at the end of the molecule. 3. The lubricant compound for a magnetic disk according to claim 1 or 2, wherein the number average molecular weight of the lubricant compound is within a range of 1000 to 4000. 4. A magnetic disk in which at least a magnetic layer, a protective layer, and a lubrication layer are sequentially provided on a substrate, characterized in that the lubrication layer contains the lubricant compound for a magnetic disk according to any one of claims 1 to 3. 5. The magnetic disk according to claim 4, wherein the protective layer is a film of a carbon protective layer formed by a plasma CVD method. 6. The magnetic disk according to claim 5, wherein the protective layer contains nitrogen on the side in contact with the lubrication layer. 7. The magnetic disk according to any one of claims 4 to 6, wherein the magnetic disk is mounted on a magnetic disk device whose start/stop mechanism is of a load-unload type. 8. A manufacturing method of a magnetic disk in which at least a magnetic layer, a protective layer, and a lubrication layer are sequentially provided on a substrate, characterized in that the lubrication layer is formed by forming a film of a lubricant composition containing the lubricant compound for a magnetic disk according to any one of claims 1 to 3 on the protective layer. 9. The manufacturing method of a magnetic disk according to claim 8, wherein after a film of the lubrication layer is formed, heating treatment is applied to the magnetic disk."
  ],
  "cpc": [
    "C10M 107/38",
    "C10M 2213/043",
    "C10M 2213/0606",
    "C10N 2020/04",
    "C10N 2040/18",
    "C10N 2050/02",
    "G11B 5/7257",
    "G11B 5/8408"
  ],
  "assignees": [
    "HAMAKUBO KATSUSHI",
    "ITOH KAE",
    "SHIMOKAWA KOICHI",
    "WD MEDIA SINGAPORE PTE LTD"
  ],
  "filing_date": "2011-06-22",
  "publication_date": "2012-06-14",
  "priority_date": "2010-06-22",
  "application_number": "US-201113166065-A",
  "family_id": "45537917",
  "citations": [
    "US2007225183A1",
    "US2010035083A1",
    "US2012251843A1",
    "US7683012B2",
    "US8007932B2"
  ]
}