US3821156A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Polyethylene terephthalate film
Assignee: Celanese Corp
•
Filing: 1972-01-03
•
Granted: 1974-06-28
•
Expires: 1992-01-03
Abstract
Abstract A polyethylene terephthalate film having improved abrasion resistance and the method for producing the film. The film is characterized by the inclusion of dispersed particles of an inert additive and calcium carbonate.
Inventors
- 👤 G Farrar
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 22:34
CPC Classifications
C; C08; C08K; C08K3/00; C08K3/18; C08K3/24; C08K3/26; Y; Y10; Y10S; Y10S260/00; Y10S260/35
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
53 words
A film in accordance with claim 1 wherein said inert additive particles dispersed in said film ranges in amount from about 0.05 percent to about 0.3 percent by weight of the film and said calcium carbonate dispersed in said film comprises from about 0.2 percent to 0.05 percent by weight of the film.
Claim 2
Dependent Claim
23 words
A film in accordance with claim 1 wherein said average particle size of said calcium carbonate ranges from about 1 to 10 microns.
Claim 3
Dependent Claim
24 words
A film in accordance with claim 1 wherein said intrinsic viscosity of said film ranges from about 0.4 to about 1.0 deciliter per gram.
Claim 4
Dependent Claim
13 words
A film in accordance with claim 1 wherein said inert additive is silica.
Claim 5
Dependent Claim
15 words
A film in accordance with claim 1 wherein said inert additive is hydrated aluminum silicate.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-06-27 | 1977-12-27 | 1978-06-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-06-27 | 1981-12-27 | 1982-06-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-06-27 | 1985-12-27 | 1986-06-28 | $7700.00 | Window Closed / Lapsed |