US3308215A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Heat treating of polypropylene film to remove sags and wrinkles
Assignee: Imperial Chemical Industries Ltd
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Filing: 1962-12-18
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Granted: 1967-03-07
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Expires: 1982-12-18
Abstract
No abstract record available.
Inventors
- 👤 Last Anthony Graham Marshall
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 15:04
CPC Classifications
B; B29; B29C; B29C55/00; B29C55/02; B29C55/10; B29C55/12; B29C55/16; B29C61/00; B29C61/06; B29C71/00; B29K; B29K2995/00; B29K2995/0037; B29K2995/005; B29K2995/0053
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
142 words
A PROCESS FOR PREPARING A SHRINKABLE POLYPROPYLENE FILM HAVING REDUCED SAG AND WRINKLES THEREIN FOR USE IN SHRINK PACKAGING OR THE LIKE, SAID PROCESS COMPRISING THE STEPS OF PROVIDING A POLYPROPYLENE FILM WHICH HAS BEEN BIAXIALLY ORIENTED BY A TUBULAR PROCESS, HOLDING THE FILM AT ITS EDGES TO RESTRAIN TRANSVERSE SHRINKAGE AND SUBSTANTIALLY REDUCING SAGS AND WRINKLES IN THE FILM BY SUBJECTNG THE FILM TO A HEAT TREATMENT F NOT MORE THAN 100*C. WHEREIN THE TIME AND TEMPERATURE CONDITIONS OF THE TREATMENT ARE RESPECTIVELY SO SHORT AND SO LOW AS TO BE INSUFFICIENT TO EFFECT HEAT SETTING AND SUBSTANTIAL LOSS OF SHRINK-ABILITY OF THE FILM AT PACKAGING TEMPERATURES HIGHER THAN THAT OF THE HEAT TREATMENT, WHEREIN THE SHRINKAGE DURING SAID HEATING TREATMENT IS BY NOT MORE THAN 5.0% IN THE TRANSVERSE DIRECTION, AND BY NOT MORE THAN 2.0% IN THE LONGITUDINAL DIRECTION.
Claim 2
Dependent Claim
142 words
A PROCESS FOR PREPARING A SHRINKABLE POLYPROPYLENE FILM HAVING REDUCED SAG AND WRINKLES THEREIN FOR USE IN SHRINK PACKAGING OR THE LIKE, SAID PROCESS COMPRISING THE STEPS OF PROVIDING A POLYPROPYLENE FILM WHICH HAS BEEN BIAXIALLY ORIENTED BY A TUBULAR PROCESS, HOLDING THE FILM AT ITS EDGES TO RESTRAIN TRANSVERSE SHRINKAGE AND SUBSTANTIALLY REDUCING SAGS AND WRINKLES IN THE FILM BY SUBJECTNG THE FILM TO A HEAT TREATMENT F NOT MORE THAN 100*C. WHEREIN THE TIME AND TEMPERATURE CONDITIONS OF THE TREATMENT ARE RESPECTIVELY SO SHORT AND SO LOW AS TO BE INSUFFICIENT TO EFFECT HEAT SETTING AND SUBSTANTIAL LOSS OF SHRINK-ABILITY OF THE FILM AT PACKAGING TEMPERATURES HIGHER THAN THAT OF THE HEAT TREATMENT, WHEREIN THE SHRINKAGE DURING SAID HEATING TREATMENT IS BY NOT MORE THAN 5.0% IN THE TRANSVERSE DIRECTION, AND BY NOT MORE THAN 2.0% IN THE LONGITUDINAL DIRECTION.
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) | 1970-03-06 | 1970-09-05 | 1971-03-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1974-03-06 | 1974-09-05 | 1975-03-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1978-03-06 | 1978-09-05 | 1979-03-07 | $7700.00 | Window Closed / Lapsed |