Patent US4076785A successfully refreshed from Google Patents.
US4076785A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of and apparatus for increasing the production output of stretched flat film webs composed of thermoplastic material
Assignee: Hoechst AG
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Filing: 1975-06-26
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Granted: 1978-02-28
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Expires: 1995-06-26
Abstract
Abstract This invention relates to an improvement in a method for increasing the production of stretched flat film webs of thermoplastic material in which a melt of thermoplastic material is extruded from a slot die, the melt is solidified to form a film, the film is transversely stretched, the stretched film is heat-set, divided into narrower webs, and wound up, the improvement comprising extruding the melt from a slot die wider than the die normally employed for the production of a preliminary film, which usually corresponds to the width of a transverse stretching frame, dividing the melt in the longitudinal direction into at least two films, superposing the film webs, and transversely stretching said superposed webs. The invention also relates to an apparatus for performing the method.
Inventors
- 👤 Willi Johann Schmidt
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 10:18
CPC Classifications
B; B32; B32B; B32B27/00; B32B27/06; B32B27/08; B29; B29C; B29C55/00; B29C55/02; B29C55/023; B32B27/32; B32B27/36; B29C2793/00; B29C2793/0063; B29C48/00; B29C48/001; B29C48/0018; B29C48/002; B29C48/0022; B29C48/03; B29C48/07; B29C48/08; B29C48/16; B29C48/18; B29C48/21; B32B38/00; B32B38/0012; B32B2038/0028; B32B2323/00; B32B2323/10; Y; Y10; Y10S; Y10S264/00; Y10S264/73
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
153 words
In an improved method for increasing the production of stretched flat film webs of thermoplastic material in which a melt of thermoplastic material is extruded from a slot die, the melt is solidified to form a film, the film is transversely stretched, the stretched film is heat-set, the heat-set film is divided into narrower webs, and wound up, the improvement comprising extruding the melt from a slot die wider than the die normally employed for the production of a preliminary film, which usually corresponds to the width of a transverse stretching frame, using an extruder having an output corresponding to the width of said wider die, dividing the melt in the longitudinal direction into at least two films, superposing the film webs so that they are in register and non-laminated, transversely stretching said superposed non-laminated films, heat-setting the superposed films, separating the stretched and heat-set films into individual layers, and winding them up.
Claim 2
Dependent Claim
153 words
In an improved method for increasing the production of stretched flat film webs of thermoplastic material in which a melt of thermoplastic material is extruded from a slot die, the melt is solidified to form a film, the film is transversely stretched, the stretched film is heat-set, the heat-set film is divided into narrower webs, and wound up, the improvement comprising extruding the melt from a slot die wider than the die normally employed for the production of a preliminary film, which usually corresponds to the width of a transverse stretching frame, using an extruder having an output corresponding to the width of said wider die, dividing the melt in the longitudinal direction into at least two films, superposing the film webs so that they are in register and non-laminated, transversely stretching said superposed non-laminated films, heat-setting the superposed films, separating the stretched and heat-set films into individual layers, and winding them up.
Claim 3
Dependent Claim
15 words
A method according to claim 1 in which said melt is divided within the die.
Claim 4
Dependent Claim
20 words
A method according to claim 1 in which, after solidifying the melt, the films are longitudinally stretched side by side.
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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) | 1981-02-27 | 1981-08-29 | 1982-02-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-02-27 | 1985-08-29 | 1986-02-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-02-27 | 1989-08-29 | 1990-02-28 | $7700.00 | Window Closed / Lapsed |