US3262808A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of coating oriented polypropylene films with heat sealable coatings
Assignee: Imperial Chemical Industries Ltd
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Filing: 1961-10-04
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Granted: 1966-07-26
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Expires: 1981-10-04
Abstract
No abstract record available.
Inventors
- 👤 Crooks Charles Hampden
- 👤 Last Anthony Graham Marshall
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 19:28
CPC Classifications
C; C08; C08J; C08J7/00; C08J7/04; C08J7/0427; C08J7/043; C08J7/048; C08J7/052; C08J2323/00; C08J2323/02; C08J2427/00; Y; Y10; Y10S; Y10S264/00; Y10S264/28; Y10T; Y10T428/00; Y10T428/31504; Y10T428/31855; Y10T428/31909; Y10T428/31913; Y10T428/3192; Y10T428/31928
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
151 words
A METHOD FOR THE PREPARATION OF COATED FILMS OF CRYSTALLISABLE POLYPROPYLENE WHICH COMPRISES TREATING A FILM OF SAID POLYPROPYLENE WHICH HAS BEEN STRETCHED TO ORIENT IT, BUT NOT HEAT SET, TO IMPROVE THE BONDING PROPERTIES OF ITS SURFACE, BY EXPOSING THE SURFACE OF THE FILM TO A HIGH VOLTAGE ELECTRICAL STRESS ACCOMPANIED BY CORONA DISCHARGE IN THE PRESENCE OF OXYGEN, COATING THE FILM WITH A POLYMERIC HEAT SEAL COATING WHICH CAN BE HEAT SEALED AT A TEMPERATURE BELOW 170*C., AND THEN HEAT SETTING THE COATED FILM AT A TEMPERATURE IN THE RANGE 75*C. TO THE MELTING POINT WHILE CONTROLLING THE DIMENSIONS OF THE FILM SO THAT IT DOES NOT SHRINK MORE THAN 15% AND UNDER CONDITIONS OF TIME AND TEMPERATURE SUFFICIENT TO DRY THE COATING AND TO REDUCE THE LINEAR SHRINKAGE IN ANY DIRECTION IN THE PLANE OF THE FILM TO LESS THAN 6% WHEN HEATED FOR 1 MINUTE AT 120*C.
Claim 2
Independent Claim
151 words
A METHOD FOR THE PREPARATION OF COATED FILMS OF CRYSTALLISABLE POLYPROPYLENE WHICH COMPRISES TREATING A FILM OF SAID POLYPROPYLENE WHICH HAS BEEN STRETCHED TO ORIENT IT, BUT NOT HEAT SET, TO IMPROVE THE BONDING PROPERTIES OF ITS SURFACE, BY EXPOSING THE SURFACE OF THE FILM TO A HIGH VOLTAGE ELECTRICAL STRESS ACCOMPANIED BY CORONA DISCHARGE IN THE PRESENCE OF OXYGEN, COATING THE FILM WITH A POLYMERIC HEAT SEAL COATING WHICH CAN BE HEAT SEALED AT A TEMPERATURE BELOW 170*C., AND THEN HEAT SETTING THE COATED FILM AT A TEMPERATURE IN THE RANGE 75*C. TO THE MELTING POINT WHILE CONTROLLING THE DIMENSIONS OF THE FILM SO THAT IT DOES NOT SHRINK MORE THAN 15% AND UNDER CONDITIONS OF TIME AND TEMPERATURE SUFFICIENT TO DRY THE COATING AND TO REDUCE THE LINEAR SHRINKAGE IN ANY DIRECTION IN THE PLANE OF THE FILM TO LESS THAN 6% WHEN HEATED FOR 1 MINUTE AT 120*C.
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) | 1969-07-25 | 1970-01-24 | 1970-07-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1973-07-25 | 1974-01-24 | 1974-07-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1977-07-25 | 1978-01-24 | 1978-07-26 | $7700.00 | Window Closed / Lapsed |