Patent US3761553A successfully refreshed from Google Patents.
US3761553A
Expired / Lapsed
US
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Method for producing uniform drawn films
Assignee: Celanese Corp
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Filing: 1971-06-28
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Granted: 1973-09-25
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Expires: 1991-06-28
Abstract
Abstract An improved method for producing a biaxially drawn thermoplastic film of substantially uniform thickness throughout its width has been discovered by controlling heat at the die opening where film is extruded by employing a plurality of heaters which do not exceed 3 inches in width mounted along the edge of the die opening, said heaters being responsive in relation to the thickness measurement of a plurality of loci across the width of the drawn sheet to maintain thickness of the film substantially constant.
Inventors
- 👤 J Richardson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 05:41
CPC Classifications
B; B29; B29C; B29C48/00; B29C48/25; B29C48/88; B29C48/911; B29C48/9135; B29C48/914; B29B; B29B7/00; B29B7/30; B29B7/58; B29B7/582; B29B7/72; B29C48/03; B29C48/07; B29C48/08; B29C48/78; B29C48/86; B29C48/865; B29C48/92; B29B7/34; B29B7/38; B29C2948/00; B29C2948/92; B29C2948/92009; B29C2948/92114; B29C2948/92152; B29C2948/92323; B29C2948/92447; B29C2948/92504; B29C2948/92704; B29C2948/92819; B29C2948/92857; B29C2948/92904; B29C48/001; B29C48/0018; B29C48/09; B29C48/10
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
35 words
The improved method of claim 1 wherein the temperature of the die opening is controlled by heaters ranging in width from about 0.5 inch to about 3 inches along the length of the die opening.
Claim 2
Dependent Claim
32 words
The improved method of claim 2 wherein the temperature of the die opening is controlled by heaters ranging from 0.5 inch to about 2 inches along the length of the die opening.
Claim 3
Dependent Claim
32 words
The improved method of claim 1 wherein the thermoplastic film is composed of polyethylene terephthalate and the film is drawn in the length and width directions at least 2.5 its original dimensions.
Claim 4
Dependent Claim
35 words
The improved method of claim 4 wherein the temperature of the die opening is controlled by heaters ranging in width from about 0.5 inch to about 3 inches along the length of the die opening.
Claim 5
Dependent Claim
32 words
The improved method of claim 5 wherein the temperature of the die opening is controlled by heaters ranging from 0.5 inch to about 2 inches along the length of the die opening.
References Cited (Backward Citations)
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-09-24 | 1977-03-26 | 1977-09-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-09-24 | 1981-03-26 | 1981-09-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-09-24 | 1985-03-26 | 1985-09-25 | $7700.00 | Window Closed / Lapsed |