Patent US4725472A successfully refreshed from Google Patents.
US4725472A
Expired / Lapsed
US
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Biaxially oriented polyester film
Assignee: Toray Industries Inc
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Filing: 1987-01-14
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Granted: 1988-02-16
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Expires: 2007-01-14
Abstract
Abstract A biaxially oriented polyester film is provided, which has a plurality of depressions and a plurality of protrusions on at least one surface thereof, in a configuration such that at least one protrusion exists within each depression or at least protrusion exists in the area where two or more depressions are contiguous to each other depressions having an area fraction of from 1×10 -3 to 6×10 -1 . The polyester film is useful as a substrate for magnetic recording tapes such as audio and video tapes, and the resultant magnetic recording tapes are excellent in both electromagnetic transducing characteristics and runnability.
Inventors
- 👤 Kazuo Okabe
- 👤 Masahiko Motegi
- 👤 Yasuki Miura
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 16:20
CPC Classifications
C; C08; C08J; C08J5/00; C08J5/18; G; G11; G11B; G11B5/00; G11B5/62; G11B5/73; G11B5/739; G11B5/73923; G11B5/73927; G11B5/73935; C08J2367/00; C08J2367/02; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10S428/91; Y10T; Y10T428/00; Y10T428/24; Y10T428/24355; Y10T428/24372; Y10T428/24405; Y10T428/24479; Y10T428/31504; Y10T428/31786
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
89 words
A biaxially oriented polyester film which has a plurality of depressions and a plurality of protrusions on at least one surface thereof, in a configuration such that at least one protrusion exists within each depression or at least one protrusion exists in the area where two or more depressions are contiguous to each other, said depressions having an area fraction of from 1×10 -3 to 6×10 -1 and said film containing at least one type of particles selected from the group consisting of inert inorganic particles and internal particles.
Claim 2
Dependent Claim
89 words
A biaxially oriented polyester film which has a plurality of depressions and a plurality of protrusions on at least one surface thereof, in a configuration such that at least one protrusion exists within each depression or at least one protrusion exists in the area where two or more depressions are contiguous to each other, said depressions having an area fraction of from 1×10 -3 to 6×10 -1 and said film containing at least one type of particles selected from the group consisting of inert inorganic particles and internal particles.
Claim 3
Dependent Claim
24 words
A biaxially oriented polyester film according to claim 1, wherein said depressions have an area fraction of from 3×10 -3 to 4×10 -1 .
Claim 4
Dependent Claim
23 words
A biaxially oriented polyester film according to claim 1, wherein said depressions have an area average diameter of from 0.5 to 5 microns.
Claim 5
Dependent Claim
23 words
A biaxially oriented polyester film according to claim 1, wherein said depressions have an area average diameter of from 1 to 3 microns.
Claim 6
Dependent Claim
37 words
A biaxially oriented polyester film according to claim 1, wherein the center line average roughness of the surface, on which the depressions and the protrusions have been formed, is in the range of from 0.07 to 0.003μ.
Claim 7
Dependent Claim
37 words
A biaxially oriented polyester film according to claim 1, wherein the center line average roughness of the surface, on which the depressions and the protrusions have been formed, is in the range of from 0.04 to 0.006μ.
Claim 8
Dependent Claim
16 words
A biaxially oriented polyester film according to claim 1, wherein said film is a semi-tensilized film.
Claim 9
Dependent Claim
16 words
A biaxially oriented polyester film according to claim 1, wherein said film is a tensilized film.
Claim 10
Dependent Claim
37 words
A biaxially oriented polyester film according to claim 1, wherein the amount of said particles contained in the film is in the range of from 0.01 to 1.0% by weight based on the weight of the film.
Claim 11
Dependent Claim
37 words
A biaxially oriented polyester film according to claim 1, wherein the amount of said particles contained in the film is in the range of from 0.02 to 0.5% by weight based on the weight of the film.
Claim 12
Dependent Claim
25 words
A biaxially oriented polyester film according to claim 1, wherein said inert inorganic particles have a volume average particle diameter of from 5 to 0.01μ.
Claim 13
Dependent Claim
25 words
A biaxially oriented polyester film according to claim 1, wherein said inert inorganic particles have a volume average particle diameter of from 2 to 0.03μ.
Claim 14
Dependent Claim
24 words
A biaxially oriented polyester film according to claim 1, wherein said internal particles have a volume average particle diameter of 5 to 0.1 micron.
Claim 15
Dependent Claim
23 words
A biaxially oriented polyester film according to claim 1, wherein said internal particles have a volume average particle diameter of 3 to 0.5μ.
Claim 16
Dependent Claim
34 words
A biaxially oriented polyester film according to claim 1, wherein said inert inorganic particles are at least one type of particles selected from the group consisting of SiO 2 , CaCO 3 and kaolinite.
Claim 17
Dependent Claim
18 words
A biaxially oriented polyester film according to claim 1, wherein said inert inorganic particles are SiO 2 particles.
Claim 18
Dependent Claim
54 words
A biaxially oriented polyester film according to claim 1, wherein said polyester is a homopolymer obtained by the polycondensation of terephthalic acid or naphthalenedicarboxylic acid with ethylene glycol, or a copolymer containing at least 70% by weight of the recurring units derived by the polycondensation of terephthalic acid or naphthalene-dicarboxylic acid with ethylene glycol.
Claim 19
Dependent Claim
15 words
A biaxially oriented polyester film according to claim 1, wherein said polyester is polyethylene terephthalate.
Claim 20
Dependent Claim
25 words
A biaxially oriented polyester film according to claim 1, wherein said depressions and said protrusions are formed on both the surfaces of the polyester film.
Claim 21
Dependent Claim
55 words
A biaxially oriented polyester film according to claim 1, wherein said internal particles are insoluble particles precipitated during the polycondensation stage of polymerization by the reaction of monomer or oligomer with catalyst residue or anti-coloring agent containing a member of the group consisting of Ca, Si, Mn, Mg, Sb, Ge, P, Li, K and Na.
References Cited (Backward Citations)
GB1359892A
Cited
US3958064A
Cited
US3821156A
Cited
US4067855A
Cited
US4138386A
Cited
US4348446A
Cited
GB2087302A
Cited
US4461797A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-02-15 | 1991-08-17 | 1992-02-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-02-15 | 1995-08-17 | 1996-02-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-02-15 | 1999-08-17 | 2000-02-16 | $7700.00 | Window Closed / Lapsed |