US4138386A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Polyester film for magnetic tape
Assignee: Toray Industries Inc
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Filing: 1977-09-29
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Granted: 1979-02-06
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Expires: 1997-09-29
Abstract
Abstract Polyester film for magnetic tape including discrete polyester particles containing lithium, calcium and phosphorus, said particles having an average size in the range from 0.1 to 3.0 mu m and inert pigments having an average size of 1.0 to 10.0 mu m.
Inventors
- 👤 Masahiko Motegi
- 👤 Saburo Fujita
- 👤 Kazuo Okabe
- 👤 Yasuki Miura
- 👤 Satoyuki Minami
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 11:04
CPC Classifications
C; C08; C08K; C08K13/00; C08K13/02; C08K3/00; C08K3/10; C08L; C08L67/00; C08L67/02; G; G11; G11B; G11B5/00; G11B5/62; G11B5/73; G11B5/739; G11B5/73923; G11B5/73927; G11B5/73935; Y; Y10; Y10S; Y10S260/00; Y10S260/35
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
156 words
A biaxially oriented polyester film for magnetic tape, said film consisting essentially of ethylene terephthalate units, said film including discrete polyester particles in the form of a metal-polymer complex in an amount of from about 0.05% to 1.0%, based on the weight of film, said particles having an average size in the range of about 0.1 to 3.0 μm and containing about 0.03% to 5.0% of elemental lithium, about 0.03% to 5.0% of elemental calcium and about 0.03% to 10.0% of elemental phosphorus, said percentages being based on the total weight of the polyester particles, and said film also including inert pigments in an amount of about 0.001% to 0.7% based on the weight of said film, said inert pigments being selected from the group consisting of oxides and salts of metals in Groups II, III, and IV of the Periodic Table, and having an average size in the range of about 1.0 to 10.0 μm.
Claim 2
Dependent Claim
156 words
A biaxially oriented polyester film for magnetic tape, said film consisting essentially of ethylene terephthalate units, said film including discrete polyester particles in the form of a metal-polymer complex in an amount of from about 0.05% to 1.0%, based on the weight of film, said particles having an average size in the range of about 0.1 to 3.0 μm and containing about 0.03% to 5.0% of elemental lithium, about 0.03% to 5.0% of elemental calcium and about 0.03% to 10.0% of elemental phosphorus, said percentages being based on the total weight of the polyester particles, and said film also including inert pigments in an amount of about 0.001% to 0.7% based on the weight of said film, said inert pigments being selected from the group consisting of oxides and salts of metals in Groups II, III, and IV of the Periodic Table, and having an average size in the range of about 1.0 to 10.0 μm.
Claim 3
Dependent Claim
41 words
A biaxially oriented polyester film for magentic tape according to claim 1 in which polyester particles contain about 0.05 to 4.0 weight % of lithium, about 0.05 to 4.0 weight % of calcium, about 0.05 to 7.5 weight % of phosphorus.
Claim 4
Dependent Claim
27 words
A polyester film for magnetic tape according to claim 1 in which the quantity of polyester particles in the film is about 0.1 to 0.5 weight %.
Claim 5
Dependent Claim
27 words
A polyester film for magnetic tape according to claim 1 in which the quantity of inert pigments in the film is about 0.003 to 0.5 weight %.
Claim 6
Dependent Claim
28 words
A polyester film for magnetic tape according to claim 1 in which the average size of the polyester particles in the film is about 0.6 to 2.5 μm.
Claim 7
Dependent Claim
27 words
A polyester film for magnetic tape according to claim 1 in which the average size of inert pigments in the film is about 1.5 to 7.0 μm.
Claim 8
Dependent Claim
26 words
A polyester film for magnetic tape according to claim 1 in which the average size of inert pigments is greater than that of the polyester particles.
Claim 9
Dependent Claim
38 words
A polyester film for magnetic tape according to claim 1 in which the maximum surface roughness of the film is about 0.05 to 0.5 μm and the density of surface protrusions is at least about 20 per mm.
Claim 10
Dependent Claim
38 words
A polyester film for magnetic tape according to claim 1 in which the maximum surface roughness of the film is about 0.05 to 0.35 μm and the density of surface protrusions is at least about 20 per mm.
Claim 11
Dependent Claim
38 words
A polyester film for magnetic tape according to claim 1 in which the maximum surface roughness of the film is about 0.05 to 0.35 μm and the density of surface protrusions is at least about 30 per mm.
Claim 12
Dependent Claim
41 words
A polyester film for magnetic tape according to claim 8 in which the number of rough protrusions having a height in the range of about 0.35 to 5.0 μm is equal to or less than about 10 per mm 2 .
Claim 13
Dependent Claim
18 words
A polyester film for magnetic tape according to claim 1 in which said inert pigments are calcium carbonate.
Claim 14
Dependent Claim
19 words
A polyester film for magnetic tape according to claim 1 in which said inert pigments are CaHPO 4 .
Claim 15
Dependent Claim
23 words
A polyester film for magnetic tape according to claim 1 in which the lithium compound added to form polyester particles is lithium acetate.
Claim 16
Dependent Claim
23 words
A polyester film for magnetic tape according to claim 1 in which the calcium compound added to form polyester particles is calcium acetate.
Claim 17
Dependent Claim
22 words
A polyester film for magnetic tape according to claim 1 in which the phosphorus compound added to form polyester particles is trimethylphosphate.
References Cited (Backward Citations)
US4008207A
Cited
US3962189A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1982-02-05 | 1982-08-07 | 1983-02-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-02-05 | 1986-08-07 | 1987-02-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-02-05 | 1990-08-07 | 1991-02-06 | $7700.00 | Window Closed / Lapsed |