US4096109A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Polyester films useful as magnetic tapes
Assignee: Mitsubishi Chemical Corp
•
Filing: 1976-07-16
•
Granted: 1978-06-20
•
Expires: 1996-07-16
Abstract
Abstract A polyester film is disclosed which comprises (a) a polyester mainly consisting of polyethylene terephthalate which includes first inert particles being precipitated in the polyester-forming reaction system and having an average particle diameter of 1 to 3 microns and which shows a solution haze of 25 to 75% and (b) an additive amount of second inert substance particles which are added to said polyester (a) insoluble in said polyester (a), inert to the polyester-forming reaction and have an average particle diameter of 1 to 5 microns. The film is useful as a base of a magnetic tape.
Inventors
- 👤 Masamichi Watanabe
- 👤 Takuo Nakahara
- 👤 Seiji Sakamoto
- 👤 Kunio Bizen
- 👤 Akikazu Yano
- 👤 Yuzo Otani
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 01:16
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/73; G11B5/739; G11B5/73923; G11B5/73927; Y; Y10; Y10S; Y10S260/00; Y10S260/35
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
124 words
A polyester film useful as a magnetic tape comprising (a) a polyester mainly consisting of polyethylene terephthalate which includes first inert particles being precipitated in the polyester-forming reaction system and having an average particle diameter of 1 to 3 microns and which shows a solution haze of 25 to 75% and (b) 0.005 to 0.15% by weight of second inert particles which are added to said polyester (a), substantially insoluble in said polyester (a) and inert to the polyester-forming reaction and have an average particle diameter of 1 to 5 microns, with the proviso that a portion of said second inert particles which consists of particles having a particle size of 3 to 6 microns is 0.004 to 0.08% by weight of said polyester.
Claim 2
Dependent Claim
124 words
A polyester film useful as a magnetic tape comprising (a) a polyester mainly consisting of polyethylene terephthalate which includes first inert particles being precipitated in the polyester-forming reaction system and having an average particle diameter of 1 to 3 microns and which shows a solution haze of 25 to 75% and (b) 0.005 to 0.15% by weight of second inert particles which are added to said polyester (a), substantially insoluble in said polyester (a) and inert to the polyester-forming reaction and have an average particle diameter of 1 to 5 microns, with the proviso that a portion of said second inert particles which consists of particles having a particle size of 3 to 6 microns is 0.004 to 0.08% by weight of said polyester.
Claim 3
Dependent Claim
27 words
The polyester film according to claim 1 wherein said second inert particles are particles selected from the group consisting of calcium terephthalate, calcium carbonate and lithium fluoride.
Claim 4
Dependent Claim
17 words
The polyester film according to claim 2 wherein said second inert particles are calcium terephthalate anhydride particles.
Claim 5
Dependent Claim
16 words
The polyester film according to claim 1 wherein said first inert substance contains calcium and/or lithium.
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) | 1981-06-19 | 1981-12-19 | 1982-06-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-06-19 | 1985-12-19 | 1986-06-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-06-19 | 1989-12-19 | 1990-06-20 | $7700.00 | Window Closed / Lapsed |