Magnetic recording medium having organic protective overlayer

Claim 2

A process for producing a magnetic recording medium having an organic protective layer which comprises forming an organic protective layer on a magnetic recording layer, which has been formed on a surface of a substrate, by sputtering conducted in an inert gas atmosphere or mixed gas atmosphere using a material for forming the organic protective layer as cathode and the magnetic recording layer as anode, wherein the material for forming the organic protective layer is at least one member selected from the group consisting of an aromatic polyimide, an aromatic polyamide, an aromatic polyamide-imide, a polyphenylene oxide, a polyphenylene sulfide, an aromatic polyurethane, a polyimidazopyrrolone, a polybenzoic acid ester, a polyoxadiazole, a polybenzothiazole, a polyquinoxaline and a polysulfone.

Claim 3

A process according to claim 1, wherein the sputtering is conducted in an inert gas of at least one member selected from the group consisting of argon, helium and xenon under a vacum of 10 -4 to 1 torr at an applied electrical power of 0.1 to 50 W/cm 2 and a frequency of 10 kHz to 10 GHz.

Claim 4

A process according to claim 1, wherein the material for forming the organic protective layer is at least one member selected from the group consisting of an aromatic polyimide, an aromatic polyamide-imide, a polyphenylene oxide, a polyphenylene sulfide, a polyimidazopyrrolone, a polybenzoic acid ester, a polyoxadiazole, a polybenzothiazole, a polyquinoxaline and a polysulfone.

Claim 5

A process according to claim 1, wherein the material for forming the organic protective layer is at least one member selected from the group consisting of an aromatic polyimide, an aromatic polyamide, an aromatic polyamide-imide, a polyphenylene oxide, a polyphenylene sulfide, an aromatic polyurethane, a polybenzoic acid ester, a polybenzothiazole, and a polyquinoxaline.

Claim 6

A process according to claim 1, wherein the material for forming the organic protective layer is at least one member selected from the group consisting of aromatic polyimide and aromatic polyurethane.

Claim 7

A process according to claim 1, wherein the material for forming the organic protective layer is at least one member selected from the group consisting of an aromatic polyurethane, an aromatic polyimide, an aromatic polyamide-imide, a polyphenylene oxide, a polyphenylene sulfide, a polyimidazopyrrolone, a polybenzoic acid ester, a polyoxadiazole, a polybenzothiazole, a polyquinoxaline and a polysulfone.

Claim 8

A process according to claim 1, wherein the sputtering is conducted in a mixed gas, said mixed gas being at least one of Ar, He and Xe and at least one of O 2 , N 2 and a halogen gas.

Claim 9

A process according to claim 1, wherein the organic protective layer is formed to have a thickness of 20-5000 Å.

Claim 10

A process according to claim 8, wherein said thickness is 50-500 Å.

Claim 11

A process according to claim 1, wherein the sputtering is conducted in an inert gas.

Claim 12

A process according to claim 10, wherein the inert gas is at least one member selected from the group consisting of Ar, He ad Xe.

Claim 13

A magnetic recording medium comprising a substrate, a magnetic recording layer formed on a surface of the substrate, and an organic protective layer formed on the magnetic recording layer, said organic protective layer being produced by sputtering conducted in an inert gas atmosphere or a mixed gas atmosphere using a material for forming the organic protective layer as cathode and the magnetic recording layer as anode, wherein the material for forming the organic protective layer is at least one member selected from the group consisting of an aromatic polyimide, an aromatic polyamide, an aromatic polyamide-imide, a polyphenylene oxide, a polyphenylene sulfide, an aromatic polyurethane, a polyimidazopyrrolone, a polybenzoic acid ester, a polyoxadiazole, a polybenzothiazol, a polyquinoxaline, and a polysulfone.

Claim 14

A magnetic recording medium comprising a substrate, a magnetic recording layer formed on a surface of the substrate, and an organic protective layer formed on the magnetic recording layer, said organic protective layer being produced by sputtering conducted in an inert gas atmosphere or a mixed gas atmosphere using a material for forming the organic protective layer as cathode and the magnetic recording layer as anode, wherein the material for forming the organic protective layer is at least one member selected from the group consisting of an aromatic polyimide, an aromatic polyamide, an aromatic polyamide-imide, a polyphenylene oxide, a polyphenylene sulfide, an aromatic polyurethane, a polyimidazopyrrolone, a polybenzoic acid ester, a polyoxadiazole, a polybenzothiazol, a polyquinoxaline, and a polysulfone.

Claim 15

A magnetic recording medium according to claim 12, wherein the sputtering is conducted in an inert gas of at least one member selected from the group consisting of argon, helium and xenon under a vacuum of 10 -4 to 1 torr at an applied electrical power of 0.1 to 50 W/cm 2 and a frequency of 10 kHz to 10 GHz.

Claim 16

A magnetic recording medium according to claim 12, wherein said organic protective layer has a thickness of 20-5000 Å.

Claim 17

A magnetic recording medium according to claim 14, wherein said thickness is 50-500 Å.

Claim 18

A magnetic recording medium according to claim 12, wherein the material for forming the organic protective layer is at least one member selected from the group consisting of an aromatic polyimide, an aromatic polyamide-imide, a polyphenylene oxide, a polyphenylene sulfide, a polyimidazopyrrolone, a polybenzoic acid ester, a polyoxadiazole, a polybenzothiazole, a polyquinoxaline, and a polysulfone.

Claim 19

A magnetic recording medium according to claim 12, wherein the material for forming the organic protective layer is at least one member selected from the group consisting of an aromatic polyimide, an aromatic polyamide, an aromatic polyamide-imide, a polyphenylene oxide, a polyphenylene sulfide, an aromatic polyurethane, a polybenzoic acid ester, a polybenzothiazole, and a polyquinoxaline.

Claim 20

A magnetic recording medium according to claim 12, wherein the material for forming the organic protective layer is at least one member selected from the group consisting of aromatic polyimide and aromatic polyurethane.

Claim 21

A magnetic recording medium according to claim 12, wherein the material for forming the organic protective layer is at least one member selected from the group consisting of an aromatic polyurethane, an aromatic polyimide, an aromatic polyamide-imide, a polyphenylene oxide, a polyphenylene sulfide, a polyimidazopyrrolone, a polybenzoic acid ester, a polyoxadiazole, a polybenzothiazole, a polyquinoxaline, and a polysulfone.