Magnetic recording medium comprising a protective layer and a lubricant layer which contains a host multidentate ligand and a guest reversibly trapped lubricant

• US 5,536,577 A
• Filed: 09/28/1994
• Issued: 07/16/1996
• Est. Priority Date: 09/28/1993
• Status: Expired due to Fees

• Current Assignee: Mitsubishi Chemical Corporation (Mitsubishi Chemical Group Corp.)
• Original Assignee: Mitsubishi Chemical Corporation (Mitsubishi Chemical Group Corp.)
• Inventors: Yokoyama, Fumiaki, Murayama, Hideki, Teranishi, Yutaka, Sano, Keiichiro, Sawada, Kazuhiko, Ikeuchi, Haruhiko
• Primary Examiner(s): Resan, Stevan A.
• Application Number:
  US08/313,909
• Time in Patent Office: 657 Days
• Field of Search: 428/694 TP, 428/694 TF, 428/694 TC, 428/900
• US Class Current: 428/408
• CPC Class Codes: B05D 1/185 applying monomolecular layers B05D1/204 takes precedence
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: B82Y 40/00 Manufacture or treatment of nanostructures
• CPC Class Codes: C10M 105/24 having only one carboxyl group bound to an acyclic carbon atom, cycloaliphatic carbon atom or hydrogen
• CPC Class Codes: C10M 105/60 having amino groups bound to an acyclic or cycloaliphatic carbon atom
• CPC Class Codes: C10M 105/64 having amino groups bound to a carbon atom of a six-membered aromatic ring
• CPC Class Codes: C10M 105/68 Amides; Imides
• CPC Class Codes: C10M 105/70 as ring hetero atom
• CPC Class Codes: C10M 107/38 containing halogen
• CPC Class Codes: C10M 2207/021 having hydroxy groups bound to acyclic or cycloaliphatic carbon atoms
• CPC Class Codes: C10M 2207/044 Cyclic ethers having four or more ring atoms, e.g. furans, dioxolanes
• CPC Class Codes: C10M 2207/125 having hydrocarbon chains of eight up to twenty-nine carbon atoms, i.e. fatty acids
• CPC Class Codes: C10M 2207/129 having hydrocarbon chains of thirty or more carbon atoms
• CPC Class Codes: C10M 2213/00 Organic macromolecular compounds containing halogen as ingredients in lubricant compositions
• CPC Class Codes: C10M 2213/04 obtained from monomers containing carbon, hydrogen, halogen and oxygen
• CPC Class Codes: C10M 2213/06 Perfluoro polymers
• CPC Class Codes: C10M 2215/08 Amides
• CPC Class Codes: C10M 2215/082 containing hydroxyl groups; Alkoxylated derivatives
• CPC Class Codes: C10M 2215/22 Heterocyclic nitrogen compounds
• CPC Class Codes: C10M 2215/221 Six-membered rings containing nitrogen and carbon only
• CPC Class Codes: C10M 2215/225 : the rings containing both nitrogen and oxygen
• CPC Class Codes: C10M 2215/226 : Morpholines
• CPC Class Codes: C10M 2215/28 : Amides; Imides
• CPC Class Codes: C10M 2215/30 : Heterocyclic compounds
• CPC Class Codes: C10M 2219/042 : Sulfate esters
• CPC Class Codes: C10M 2219/044 : Sulfonic acids, Derivatives thereof, e.g. neutral salts
• CPC Class Codes: C10M 2223/04 : Phosphate esters
• CPC Class Codes: C10M 2223/042 : Metal salts thereof
• CPC Class Codes: C10M 2223/047 : Thioderivatives not containing metallic elements
• CPC Class Codes: C10N 2010/02 : Groups 1 or 11
• CPC Class Codes: C10N 2040/14 : Electric or magnetic purposes
• CPC Class Codes: C10N 2040/16 : Dielectric; Insulating oil or insulators
• CPC Class Codes: C10N 2040/17 : for electric contacts
• CPC Class Codes: C10N 2040/175 : Pantographs, i.e. printing devices
• CPC Class Codes: C10N 2040/18 : in connection with recordings on magnetic tape or disc
• CPC Class Codes: C10N 2040/185 : Magnetic fluids
• CPC Class Codes: G11B 5/725 : containing a lubricant , e.g. organic compounds inorganic carbon protective coating G11B5/727
• CPC Class Codes: Y10S 428/90 : Magnetic feature
• CPC Class Codes: Y10S 428/91 : Product with molecular orientation
• CPC Class Codes: Y10T 428/30 : Self-sustaining carbon mass or layer with impregnant or other layer
• CPC Class Codes: Y10T 428/31504 : Composite [nonstructural laminate]
• CPC Class Codes: Y10T 428/31536 : Including interfacial reaction product of adjacent layers

Abstract

The lubricant layer according to the present invention is used in a thin film magnetic recording medium in which a solid surface sliding at a high speed is required to retain its lubricating performance and abrasion resistance for a long period of time, comprising a host-guest complex composed of a lubricant molecule as a guest molecule and a multidentate ligand as a host compound to form the complex with the guest molecule.

Claims

1. A magnetic recording medium which comprises a non-magnetic substrate having successively formed thereon a thin film magnetic layer, a protective layer, and a lubricant layer wherein, said lubricant layer contains a host-guest complex lubricant of a host compound and a guest compound having a lubricating function, in which the host compound comprises a multidentate ligand having a function to reversibly trap an organic ion or a metal ion by electrostatic interaction.

2. The magnetic recording medium according to claim 1, wherein the quest compound of said host-guest complex lubricant comprises an organic or metal ion having a function to be reversibly trapped by the multidentate ligand of the host compound, said ion being bound to a moiety which imparts a lubricating function to the complex.

3. The magnetic recording medium according to claim 1, wherein said host compound is coated on the surface of the protective layer.

4. The magnetic recording medium according to claim 1, wherein said multidentate ligand has terminal functional groups providing an electrostatic interaction with each other.

5. The magnetic recording medium according to claim 1, wherein said multidentate ligand is a compound having three or more atoms of at least one element selected from the group consisting of oxygen nitrogen, and sulfur.

6. The magnetic recording medium according to claim 1, wherein said host compound is a cyclic multidentate ligand and corresponding donor atoms contain a lone electron pair having an sp³ hybrid orbital.

7. The magnetic recording medium according to claim 1, wherein said host compound is a crown ether having terminal hydroxyl groups.

8. The magnetic recording medium according to claim 1, wherein said host compound is a cyclofructan.

9. The magnetic recording medium according to claim 1, wherein the guest compound is derived from a compound having 8 or more carbon atoms and having an active hydrogen at one terminal.

10. A magnetic recording medium which comprises a non-magnetic substrate having successively formed thereon a magnetic layer, a carbonaceous protective layer, and a lubricant layer, wherein said lubricant layer contains a host-guest complex lubricant, in which a lubricant molecule is used as a guest compound and a multidentate ligand is used as a host compound, and is arranged on the surface of the carbonaceous protective layer which has been treated so as to increase the number of acidic functional groups.

13. The magnetic recording medium according to claim 10 or 11, wherein said multidentate ligand contains three or more atoms of at least one element selected from the group consisting of oxygen, nitrogen, and sulfur and has a function to trap a metal ion or an organic ion.

14. The magnetic recording medium according to claim 10 or 11, wherein said multidentate ligand has one or more basic functional groups.

11. A magnetic recording medium which comprises a non-magnetic substrate having successively formed thereon a magnetic layer, a carbonaceous protective layer, and a lubricant layer, wherein the surface of said carbonaceous protective layer has a ratio of the C═

O bond to the C--C bond and the C--H bond ranging from 0.05 to 0.3 and the lubricant layer contains a host-guest complex lubricant in which a lubricant molecule is used as a guest compound and a multidentate ligand is used as a host compound.

12. The magnetic recording medium according to claim 11, wherein said ratio of the C═

O bond to the C--C bond and the C--H bond ranges from 0.07 to 0.2.