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US5149481A
Expired / Lapsed
US
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Method of manufacturing thermoplastic sheet or film
Assignee: Roehm GmbH Darmstadt
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Filing: 1991-06-10
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Granted: 1992-09-22
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Expires: 2011-06-10
Abstract
Abstract An extruded, smooth finished solid sheet or film of thickness <1 mm is prepared from a thermoplastic plastic having a glass transition temperature >50° C., by extruding the plastic in the thermoplastic state through a slot nozzle to form a flat extruded strip, which is introduced into the roll gap of a roll stack having a smoothed upper roll and a lower roll, with the upper roll being maintained at a temperature below the glass transition temperature of the thermoplastic plastic and with the lower roll being maintained at a temperature in the plastic state domain of the thermoplastic plastic, and, after exiting the roll gap, the extruded strip is moved resting on a smooth-finished endless belt which passes around the lower roll, thereby smoothing the surface of the strip; and cooling said extruded strip below the glass transition temperature.
Inventors
- 👤 Heinz Gross
- 👤 Andreas Fetzer
- 👤 Gunther Dickhaut
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 02:15
CPC Classifications
B; B29; B29C; B29C35/00; B29C35/16; B29C48/00; B29C48/001; B29C48/03; B29C48/07; B29C48/08; B29C48/25; B29C48/88; B29C48/911; B29C48/9135; B29C48/9145; B29C48/915; B29C48/9155; B29C59/00; B29C59/02; B29C59/04
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
142 words
A method of manufacturing an extruded, smooth finished solid sheet or film of thickness <1 mm, from a thermoplastic plastic having a glass transition temperature >50° C., by extruding the plastic in a thermoplastic state through a slot nozzle to form a flat extruded strip, which is introduced into the roll gap of a roll stack having a smoothed upper roll and a lower roll, with the upper roll being maintained at a temperature below the glass transition temperature of the thermoplastic plastic and with the lower roll being maintained at a temperature in the plastic state domain of the thermoplastic plastic, and, after exiting the roll gap, the extruded strip is moved resting on a smooth-finished endless belt which passes around the lower roll, thereby smoothing the surfaces of the strip; and cooling said extruded strip below the glass transition temperature.
Claim 2
Independent Claim
142 words
A method of manufacturing an extruded, smooth finished solid sheet or film of thickness <1 mm, from a thermoplastic plastic having a glass transition temperature >50° C., by extruding the plastic in a thermoplastic state through a slot nozzle to form a flat extruded strip, which is introduced into the roll gap of a roll stack having a smoothed upper roll and a lower roll, with the upper roll being maintained at a temperature below the glass transition temperature of the thermoplastic plastic and with the lower roll being maintained at a temperature in the plastic state domain of the thermoplastic plastic, and, after exiting the roll gap, the extruded strip is moved resting on a smooth-finished endless belt which passes around the lower roll, thereby smoothing the surfaces of the strip; and cooling said extruded strip below the glass transition temperature.
Claim 3
Dependent Claim
51 words
The method according to claim 1, wherein the strip of thermoplastic plastic is conveyed out of the extrusion nozzle at a speed such that the strip forms a bead on the inlet side of the roll gap, and such that the entire width of the strip lies continuously against both rolls.
Claim 4
Dependent Claim
32 words
The method according to claim 1, wherein the plastic is polymethylmethacrylate (PMMA), polystyrene (PS), PC, polyvinylchloride (PVC), polyvinylidene chloride (PVDC), acrylonitrile-butadiene-styrene (ABS), SAN, PES, polyethylene terephthalate (PET), PSU, PEI, PEEK or PMMI.
Claim 5
Dependent Claim
37 words
The method according to claim 1, wherein the upper roll is maintained at a temperature of 60°-140° C. and the lower roll and endless belt over the lower roll are maintained at a temperature of 160°-300° C.
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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) | 1995-09-22 | 1996-03-23 | 1996-09-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-09-22 | 2000-03-23 | 2000-09-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-09-22 | 2004-03-23 | 2004-09-22 | $7700.00 | Window Closed / Lapsed |