Super high density magnetic recording medium

Claim 2

A super high density magnetic recording medium, which comprises a coated polyester film and a ferromagnetic metal thin film formed on the coated surface of the coated polyester film, said coated polyester film comprising: (A) a linear polyester film; and (B) a discontinuous film formed on at least one surface of the linear polyester film, said discontinuous film having a net-like shape and/or a node-broken net-like shape and a thickness of not larger than 500 angstroms, and being applied to said linear polyester base film (A) over an area which is 10 to 90% of the area of said linear polyester base film (A), said discontinuous film (B) comprising: (i) a water-soluble polymer having a molecular weight of 10,000 to 2,000,000 and (ii) a silane coupling reagent.

Claim 3

A super high density magnetic recording medium as set forth in claim 1, wherein the discontinuous film comprises a silicone resin in addition to the water-soluble polymer and the silane coupling reagent, said silicone resin being polysiloxane having a molecular weight of 30,000 to 300,000.

Claim 4

A super high density magnetic recording medium as set forth in claim 1 or 2, wherein the thickness of the discontinuous film is in the range of 50 to 500 angstroms.

Claim 5

A super high density magnetic recording medium as set forth in claim 1, or 2, wherein the discontinuous film has a thickness of 50 to 500 angstroms, a short axis length of 0.05 to 10μ and a long axis length/short axis length ratio of at least 1.7.

Claim 6

A super high density magnetic recording medium as set forth in claim 1 or 2, wherein the thickness of the discontinuous film is in the range of 50 to 300 angstroms.

Claim 7

A super high density magnetic recording medium as set forth in claim 1, wherein the weight ratio of the water-soluble polymer to the silane coupling reagent is in the range of (10-200):(2-50).

Claim 8

A super high density megnetic recording medium as set forth in claim 1, wherein the weight ratio of the water-soluble polymer to the silane coupling reagent is in the range of 100:(1-10).

Claim 9

A super high density magnetic recording medium as set forth in claim 2, wherein the water-soluble polymer:silane coupling reagent:silicone resin weight ratio is in the range of (10-300):(2-50):(10-100).

Claim 10

A super high density magnetic recording medium as set forth in claim 2, wherein the water-soluble polymer:silane coupling reagent:silicone resin weight ratio is (50-250):(5-30):(20-80).

Claim 11

A super high density magnetic recording medium as set forth in claim 1 or 2, wherein the discontinuous film has a net-like shape.

Claim 12

A super high density magnetic recording medium as set forth in claim 1 or 2, wherein the discontinuous film has a node-broken net-like shape.

Claim 13

A super high density magnetic recording medium as set forth in claim 1 or 2, wherein the polyester base film is a smooth polyester film having a surface roughness value Ra of not larger than 0.015μ at a cut-off value of 0.08 mm as measured by a stylus-type surface roughness tester.

Claim 14

A super high density magnetic recording medium as set forth in claim 1 or 2, wherein the polyester base film is a smooth polyester film having a surface roughness value Ra of 0.010 to 0.002μ at a cut-off value of 0.08 mm as measured by a stylus-tape surface tester.

Claim 15

A super high density magnetic recording medium as set forth in claim 1 or 2, wherein the discontinuous film is formed on both the surfaces of the polyester base film.

Claim 16

A super high density magnetic recording medium as set forth in claim 1 or 2, wherein the polyester is at least one polyester selected from the group consisting of polyethylene terephthalate, polytetramethylene terephthalate, poly-1,4-cyclohexylenedimethylene terephthalate, polyethylene 2,6-naphthalenedicarboxylate, polyethylene p-hydroxybenzoate and copolymers thereof.

Claim 17

A super high density magnetic recording medium as set forth in claim 1 or 2, wherein the polyester base film is polyethylene terephthalate.

Claim 18

A super high density magnetic recording medium as set forth in claim 1 or 2, wherein the water-soluble polymer is a water-soluble polymer having a molecular weight of 100,000 to 1,000,000.

Claim 19

A super high density magnetic recording medium as set forth in claim 1 or 2, wherein the water-soluble polymer is at least one member selected from the group consisting of polyvinyl alcohol, tragacanth gum, gum arabic, casein, gelatin, methylcellulose, hydroxethyl cellulose and carboxymethyl cellulose.

Claim 20

A super high density magnetic recording medium as set forth in claim 1 or 2, wherein the water-soluble polymer is at least one member selected from the group consisting of methyl cellulose, hydroxyethyl cellulose and carboxymethyl cellulose.

Claim 21

A super high density magnetic recording medium as set forth in claim 1 or 2, wherein the silane coupling reagent is an organic silicon monomer having at least two different reactive groups in the molecule.

Claim 22

A super high density magnetic recording medium as set forth in claim 1 or 2, wherein the silane coupling reagent is a mono- or di-organoalkoxysilane.

Claim 23

A super high density magnetic recording medium as set forth in claim 20, wherein one of the reactive groups is selected from the group consisting of methoxy, ethoxy and silanol groups and the other reactive group is selected from the group consisting of vinyl, epoxy, methacryl, amino and mercapto groups.

Claim 24

A super high density magnetic recording medium as set forth in claim 1 or 2, wherein the silane coupling reagent is an aminosilane type compound.

Claim 25

A super high density magnetic recording medium as set forth in claim 1, 2, 35 or 37 wherein the silane coupling reagent is at least one organic silane compound selected from the group consisting of vinyltrichlorosilane, vinyltriethoxysilane, vinyl-tris(β-methoxyethoxy)silane, γ-chloropropyltrimethoxysilan and γ-mercaptopropyltrimethoxysilane.

Claim 26

A super high density magnetic recording medium as set forth in claim 2, wherein the silicone resin is a compound having a structure represented by the following formula: ##STR2## wherein R 1 stands for a methyl group, a phenyl group or a hydrogen atom, R 2 stands for a methyl group, a phenyl group, a hydrogen atom, an epoxy group, an amino group or a hydroxyl group, and n is a number of from 100 to 7,000, and containing functional terminal groups selected from the group consisting of epoxy, amino and hydroxyl groups.

Claim 27

A super high density magnetic recording medium as set forth in claim 1 or 2, wherein the polyester base film is a biaxially oriented polyester film.

Claim 28

A super high density magnetic recording medium as set forth in claim 1 or 2, wherein the poylester base film is a biaxially oriented polyester film which is tensilized in at least one of the longitudinal direction and the transverse direction.

Claim 29

A super high density magnetic recording medium as set forth in claim 1 or 2, wherein the polyester base film is a biaxially tensilized polyester film.

Claim 30

A super high density magnetic recording medium as set forth in claim 1, wherein the ferromagnetic metal thin film is a vacuum-deposited ferromagnetic metha thin film.

Claim 31

A super high density magnetic recording medium as set forth in claim 1, wherein the thickness of the ferromagnetic metal thin film is in the range of 500 to 2,000 angstroms.

Claim 32

A super high density magnetic recording medium as set forth in claim 1, wherein the ferromagnetic metal is at least one member selected from the group consisting of Fe, Co, Ni and alloys thereof.

Claim 33

A super high density magnetic recording medium as set forth in claim 1, or 2, wherein the silane coupling reagent is at least one organic silane compound selected from the group consisting of γ-glycidoxypropyltrimethoxysilane, γ-methacryloxy propyltrimethoxysilane, N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane, N-β-(aminoethyl)-γ-aminopropyl methyldimethoxysilane, and γ-aminopropyltriethoxysilane.

Claim 34

A super high density magnetic recording medium, which comprises a coated polyester film and a ferromagnetic metal thin film formed on the coated surface of the coated polyester film, said coated polyester film comprising: (A) a linear polyester base film; and (B) a discontinuous film formed on at least one surface of the base film, said discontinuous film having a net-like shape and/or a node-broken net-like shape and a thickness of not larger than 500 angstroms, and being applied to said polyester base film (A) over an area which is 10 to 90% of the area of said polyester base film (A), said discontinuous film, (B) comprising: (i) a water-soluble polymer having a molecular weight of 10,000 to 2,000,000; and (ii) a silane coupling reagent operative and effective to bond said base film (A) to said discontinuous film (B).

Claim 35

A super high density magnetic recording medium, which comprises a coated polyester film and a ferromagnetic metal thin film formed on the coated surface of the coated polyester film, said coated polyester film comprising: (A) a linear polyester base film; and (B) a discontinuous film formed on at least one surface of the base film, said discontinuous film having a net-like shape and/or a node-broken net-like shape and a thickness of not larger than 500 angstroms, and being applied to said polyester base film (A) over an area which is 10 to 90% of the area of said polyester base film (A), said discontinuous film, (B) comprising: (i) a water-soluble polymer having a molecular weight of 10,000 to 2,000,000; and (ii) a silane coupling reagent operative and effective to bond said base film (A) to said discontinuous film (B).

Claim 36

A super high density magnetic recording medium, which comprises a coated polyester film and a ferromagnetic metal thin film formed on the coated surface of the coated polyester film, said coated polyester film comprising: (A) a linear polyester base film; and (B) a discontinuous film formed on at least one surface of the base film, said discontinuous film having a net-like shape and/or a node-broken net-like shape and a thickness of not larger than 500 angstroms, and being applied to said polyester base film (A) over an area which is 10 to 90% of the area of said polyester base film (A), said discontinuous film (B) comprising: (i) a water-soluble polymer having a molecular weight of 10,000 to 2,000,000; and (ii) a silane coupling reagent comprising an organic silicon monomer having in the molecular at least two different reactive groups, at least one of which is capable of linking with the water soluble polymer and at least one of which is capable of linking with the polyester.

Claim 37

A super high density magnetic recording medium, which comprises a coated polyester film and a ferromagnetic metal thin film formed on the coated surface of the coated polyester film, said coated polyester film comprising: (A) a linear polyester base film; and (B) a discontinuous film formed on at least one surface of the base film, said discontinuous film having a net-like shape and/or a node-broken net-like shape and a thickness of not larger than 500 angstroms, and being applied to said polyester base film (A) over an area which is 10 to 90% of the area of said polyester base film (A), said discontinuous film (B) comprising: (i) a water-soluble polymer having a molecular weight of 10,000 to 2,000,000; and (ii) a silane coupling reagent comprising an organic silicon monomer having in the molecular at least two different reactive groups, at least one of which is capable of linking with the water soluble polymer and at least one of which is capable of linking with the polyester.

Claim 38

The super high density magnetic recording medium as claimed in claim 34, wherein one reactive group of said silane coupling reagent is selected from the group consisting of methoxy, ethoxy and silanol groups and another reactive group is selected from the group consisting of vinyl, epoxy, methacryl, amino and mercapto groups.

Claim 39

A super high density magnetic recording medium, which comprises a coated polyester film and a ferromagnetic metal thin film formed on the coated surface of the coated polyester film, said coated polyester film comprising: (A) a linear polyester base film; and (B) a discontinuous film formed on at least one surface of the base film, said discontinuous film having a net-like shape and/or a node-broken net-like shape and a thickness of not larger than 500 angstroms, and being applied to said polyester base film (A) over an area which is 10 to 90% of the area of said polyester base film (A), said discontinuous base film (B) comprising: (i) a water-soluble polymer having a molecular weight of 10,000 to 2,000,000, (ii) a silicone resin having a molecular weight of 30,000 to 300,000; and (iii) a silane coupling reagent comprising an organic silicone monomer having in the molecule at least two different reactive groups, said reactive groups selected from those which are capable of being linked with side chain and terminal groups of the water-soluble polymer and with the side chain internal groups of the silicone resin and with the polyester.

Claim 40

A super high density magnetic recording medium, which comprises a coated polyester film and a ferromagnetic metal thin film formed on the coated surface of the coated polyester film, said coated polyester film comprising: (A) a linear polyester base film; and (B) a discontinuous film formed on at least one surface of the base film, said discontinuous film having a net-like shape and/or a node-broken net-like shape and a thickness of not larger than 500 angstroms, and being applied to said polyester base film (A) over an area which is 10 to 90% of the area of said polyester base film (A), said discontinuous base film (B) comprising: (i) a water-soluble polymer having a molecular weight of 10,000 to 2,000,000, (ii) a silicone resin having a molecular weight of 30,000 to 300,000; and (iii) a silane coupling reagent comprising an organic silicone monomer having in the molecule at least two different reactive groups, said reactive groups selected from those which are capable of being linked with side chain and terminal groups of the water-soluble polymer and with the side chain internal groups of the silicone resin and with the polyester.

Claim 41

A super high density magnetic recording medium, which comprises a coated polyester film and a ferromagnetic metal thin film formed on the coated surface of the coated polyester film, said coated polyester film comprising: (A) a linear polyester base film; and (B) a discontinuous film formed on at least one surface of the base film, said discontinuous film having a net-like shape and/or a node-broken net-like shape and a thickness of not larger than 500 angstroms, and being applied to said polyester base film (A) over an area which is 10 to 90% of the area of said polyester base film (A), said discontinuous base film (B) comprising: (i) a water-soluble polymer having a molecular weight of 10,000 to 2,000,000, and (ii) a silane coupling reagent comprising an organic silicon monomer having in the molecule at least two different reactive groups; wherein said water-soluble polymer (i) and said silane coupling reagent (ii) have a weight ratio (i)/(ii) in the range of from 200/2 to 10/50.

Claim 42

A super high density magnetic recording medium, which comprises a coated polyester film and a ferromagnetic metal thin film formed on the coated surface of the coated polyester film, said coated polyester film comprising: (A) a linear polyester base film; and (B) a discontinuous film formed on at least one surface of the base film, said discontinuous film having a net-like shape and/or a node-broken net-like shape and a thickness of not larger than 500 angstroms, and being applied to said polyester base film (A) over an area which is 10 to 90% of the area of said polyester base film (A), said discontinuous base film (B) comprising: (i) a water-soluble polymer having a molecular weight of 10,000 to 2,000,000, and (ii) a silane coupling reagent comprising an organic silicon monomer having in the molecule at least two different reactive groups; wherein said water-soluble polymer (i) and said silane coupling reagent (ii) have a weight ratio (i)/(ii) in the range of from 200/2 to 10/50.

Claim 43

A super high density magnetic recording medium, which comprises a coated polyester film and a ferromagnetic metal thin film formed on the coated surface of the coated polyester film, said coated polyester film comprising: (A) a linear polyester base film; and (B) a discontinuous film formed on at least one surface of the base film, said discontinuous film having a net-like shape and/or a node-broken net-like shape and a thickness of not larger than 500 angstroms, and being applied to said polyester base film (A) over an area which is 10 to 90% of the area of said polyester base film (A), said discontinuous base film (B) comprising: (i) a water-soluble polymer having a molecular weight of 10,000 to 2,000,000, (ii) a silicone resin having a molecular weight of 30,000 to 300,000; and (iii) a silane coupling reagent comprising an organic silicone monomer having in the molecule at least two different reactive groups, said reactive groups selected from those which are capable of being linked with side chain and terminal groups of the water soluble polymer and with the side chain internal groups of the silicone resin and with the polyester, wherein said water-soluble polymer (i), said silicone resin (ii) and said silane coupling reagent (iii) have a weight ratio in the range of (10-300):(10-100):(2-50).

Claim 44

A super high density magnetic recording medium, which comprises a coated polyester film and a ferromagnetic metal thin film formed on the coated surface of the coated polyester film, said coated polyester film comprising: (A) a linear polyester base film; and (B) a discontinuous film formed on at least one surface of the base film, said discontinuous film having a net-like shape and/or a node-broken net-like shape and a thickness of not larger than 500 angstroms, and being applied to said polyester base film (A) over an area which is 10 to 90% of the area of said polyester base film (A), said discontinuous base film (B) comprising: (i) a water-soluble polymer having a molecular weight of 10,000 to 2,000,000, (ii) a silicone resin having a molecular weight of 30,000 to 300,000; and (iii) a silane coupling reagent comprising an organic silicone monomer having in the molecule at least two different reactive groups, said reactive groups selected from those which are capable of being linked with side chain and terminal groups of the water soluble polymer and with the side chain internal groups of the silicone resin and with the polyester, wherein said water-soluble polymer (i), said silicone resin (ii) and said silane coupling reagent (iii) have a weight ratio in the range of (10-300):(10-100):(2-50).

Claim 45

A super high density magnetic recording medium, which comprises a coated polyester film and a ferromagnetic metal thin film formed on the coated surface of the coated polyester film, said coated polyester film comprising a polyester film and a discontinuous film formed on at least one surface of the polyester film, said polyester film having a surface roughness value Ra of not larger than 0.015 micron at a cut-off value of 0.08 mm as measured by a stylus-type surface roughness tester, and said discontinuous film having a net-like shape and/or a node-broken net like shape and a thickness of 50 to 500 angstroms, a short axis length of 0.05 to 10 microns, a long axis length/short axis length ratio of at least 1.7 and an area ratio of 10 to 90% and comprised of a water-soluble polymer having a molecular weight of 10,000 to 2,000,000 and a silane coupling reagent.

Claim 46

A super high density magnetic recording medium, which comprises a coated polyester film and a ferromagnetic metal thin film formed on the coated surface of the coated polyester film, said coated polyester film comprising a polyester film and a discontinuous film formed on at least one surface of the polyester film, said polyester film having a surface roughness value Ra of not larger than 0.015 micron at a cut-off value of 0.08 mm as measured by a stylus-type surface roughness tester, and said discontinuous film having a net-like shape and/or a node-broken net like shape and a thickness of 50 to 500 angstroms, a short axis length of 0.05 to 10 microns, a long axis length/short axis length ratio of at least 1.7 and an area ratio of 10 to 90% and comprised of a water-soluble polymer having a molecular weight of 10,000 to 2,000,000 and a silane coupling reagent.