US4767657A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Polyester films suitable for use in magnetic tapes
Assignee: Diafoil Co Ltd
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Filing: 1986-07-07
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Granted: 1988-08-30
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Expires: 2006-07-07
Abstract
Abstract There is disclosed a polyester film suitable for use in magnetic tapes having the characteristics represented by the following equations: N1h </= 2.3 (i) <IMAGE> (ii) n </= 1.601 (iii) wherein N1 is the number of peaks of surface projections per millimeter; &upbar& h is the average height in mu m of the surface projections; theta is the average steepness in degree of the surface projections; &upbar& H2 is the mean square height in mu m2 of the surface projections; and &upbar& n is the average refractive index.
Inventors
- 👤 Seiji Sakamoto
- 👤 Yoshio Meguro
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 07:53
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/73; G11B5/739; G11B5/73923; G11B5/73927; G11B5/73935; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10S428/91; Y10T; Y10T428/00; Y10T428/24; Y10T428/24355; Y10T428/24372; Y10T428/24413; Y10T428/24421; Y10T428/24479; Y10T428/25; Y10T428/254; Y10T428/256; Y10T428/257; Y10T428/259; Y10T428/26; Y10T428/269; Y10T428/31; Y10T428/31504; Y10T428/31786; Y10T428/31797
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
97 words
A polyester film suitable for use in magnetic tapes having the surface roughness characteristics represented by the following equations: ##EQU5## wherein N 1 is the number of peaks of surface projections per millimeter; h is the average height in μm of the surface projections; θ is the average steepness in degree of the surface projections; H 2 is the mean square height in μm 2 of the surface projections; and n is the average refractive index, the surface roughness of the film being imparted to said film by the precipitation of inert fine particles in said polyester.
Claim 2
Dependent Claim
97 words
A polyester film suitable for use in magnetic tapes having the surface roughness characteristics represented by the following equations: ##EQU5## wherein N 1 is the number of peaks of surface projections per millimeter; h is the average height in μm of the surface projections; θ is the average steepness in degree of the surface projections; H 2 is the mean square height in μm 2 of the surface projections; and n is the average refractive index, the surface roughness of the film being imparted to said film by the precipitation of inert fine particles in said polyester.
Claim 3
Dependent Claim
17 words
The polyester film of claim 1, wherein said fine particles are particles of an ester exchange catalyst.
Claim 4
Dependent Claim
101 words
A polyester film suitable for use in magnetic tapes having the surface roughness characteristics represented by the following equations: ##EQU6## wherein N 1 is the number of peaks of surface projections per millimeter; h is the average height in μm of the surface projections; θ is the average steepness in degree of the surface projections; H 2 is the mean square height of μm 2 of the surface projections; and n is the average refractive index, the surface roughness of the film being imparted to said film by the addition of microparticles to the polyester which are insoluble in the polyester.
Claim 5
Dependent Claim
101 words
A polyester film suitable for use in magnetic tapes having the surface roughness characteristics represented by the following equations: ##EQU6## wherein N 1 is the number of peaks of surface projections per millimeter; h is the average height in μm of the surface projections; θ is the average steepness in degree of the surface projections; H 2 is the mean square height of μm 2 of the surface projections; and n is the average refractive index, the surface roughness of the film being imparted to said film by the addition of microparticles to the polyester which are insoluble in the polyester.
Claim 6
Dependent Claim
26 words
The polyester film of claim 3, wherein said microparticles are oxides or salts of Group II, Group III or Group IV elements in the Periodic Table.
Claim 7
Dependent Claim
16 words
The polyester film of claim 4, wherein said microparticles have a particle size range from 0.5-3.0μ.
Claim 8
Dependent Claim
13 words
The polyester film of claim 1 or 3, wherein the polyester is polyethyleneterephthalate.
Claim 9
Dependent Claim
18 words
The polyester film of claim 1 or 3, wherein said film has a thickness of 5 to 100μ.
Claim 10
Dependent Claim
14 words
The polyester film of claim 1 or 3 wherein said film is biaxially oriented.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-08-30 | 1992-02-29 | 1992-08-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-08-30 | 1996-02-29 | 1996-08-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-08-30 | 2000-02-29 | 2000-08-30 | $7700.00 | Window Closed / Lapsed |