EP0061769A2
Expired / Lapsed
EP
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Magnetic recording medium
Assignee: Teijin Ltd
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Filing: 1982-03-30
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Granted: —
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Expires: 2002-03-30
Abstract
Abstract A magnetic recording medium composed of an oriented polyethylene terephthalate film as a support layer and a thin magnetic metallic layer formed on one surface (A) of the support layer and optionally a lubricant layer formed on the other surface (B) of the support layer; characterized in that (1) the surface A has a center-line average (CLA) of not more than 0.005 µm, (2) the surface A has a peak-to-valley (PV) value of not more than 0.06 µm, (3) the number of protrusions having a height of 0.27 to 0.54 µm on the surface A is at most 0.2 per mm 2 , and (4) the surface A is substantially free from protrusions having a height larger than 0.54 µm.
Inventors
- 👤 Tomio Adachi
- 👤 Shigeru Shiozaki
- 👤 Takashi Tomie
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-28 04:02
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/73; G11B5/739; G11B5/73923; G11B5/73927; G11B5/73935; G11B5/84; G11B5/8416; G11B5/851; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/24; Y10T428/24355; Y10T428/24479; Y10T428/24612; Y10T428/26; Y10T428/263; Y10T428/264; Y10T428/265
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
119 words
A magnetic recording medium composed of an oriented polyethylene terephthalate film as a support layer and a thin magnetic metallic layer formed on one surface (A) of the support layer and optionally a lubricant layer formed on the other surface (B) of the support layer; characterized in that (1) the surface A has a center-line average (CLA) of not more than 0.005 pm, (2) the surface A has a peak-to-valley (PV) value of not more than 0.06 µm, (3) the number of protrusions having a height of 0.27 to 0.54 µm on the surface A is at most 0.2 per mm , and (4) the surface A is substantially free from protrusions having a height larger than 0.54 pm.
Claim 2
Dependent Claim
119 words
A magnetic recording medium composed of an oriented polyethylene terephthalate film as a support layer and a thin magnetic metallic layer formed on one surface (A) of the support layer and optionally a lubricant layer formed on the other surface (B) of the support layer; characterized in that (1) the surface A has a center-line average (CLA) of not more than 0.005 pm, (2) the surface A has a peak-to-valley (PV) value of not more than 0.06 µm, (3) the number of protrusions having a height of 0.27 to 0.54 µm on the surface A is at most 0.2 per mm , and (4) the surface A is substantially free from protrusions having a height larger than 0.54 pm.
Claim 3
Dependent Claim
22 words
The magnetic recording medium of claim 1 wherein the surface A has a center-line average (CLA) of not more than 0.004 µm.
Claim 4
Dependent Claim
23 words
The magnetic recording medium of claim 1 wherein the surface A is substantially free from protrusions having a height larger than 0.27 µm.
Claim 5
Dependent Claim
101 words
The magnetic recording medium of claim 1 wherein the oriented polyethylene terephthalate film as the support layer is produced by subjecting a lower alkyl ester of a dicarboxylic acid comprising terephthalic acid as a main component and a glycol comprising ethylene glycol as a main component to an ester-interchange reaction in the presence of, as a catalyst, a compound of at least one metal selected from Mn, Zn, Ca and Mg using a glycol solution of a trialkyl phosphate as a stabilizer, polycondensing the ester-interchange reaction product, extruding the resultant polyethylene terephthalate, stretching the resulting film, and heat-setting the stretched film.
Claim 6
Dependent Claim
33 words
The magnetic recording medium of claim 1 wherein the thin magnetic metal layer is formed by vacuum evaporation, sputtering, ion plating or electroless plating, and has a thickness of 0.02 to 1.5 µm.
References Cited (Backward Citations)
No citation records indexed.
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