US4859392A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process and device for the production of plastic films
Assignee: Roehm GmbH Darmstadt
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Filing: 1988-05-24
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Granted: 1989-08-22
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Expires: 2008-05-24
Abstract
Abstract A smooth film web is used as a smoothing surface in the nip between a cooling roll and a pressure roll. The pressure roll need not be coolable, and it preferably has an elastic surface layer. Since the elastic surface layer does not come into immediate contact with the extruded web, it need not be highly polished. Consequently, a high running time is achieved.
Inventors
- 👤 Heinz Vetter
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 18:57
CPC Classifications
B; B29; B29C; B29C59/00; B29C59/02; B29C59/04; B29C43/00; B29C43/22; B29C43/222; B29C43/24; B29C48/00; B29C48/03; B29C48/07; B29C48/08
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
167 words
A process for the production of plastic film, said process comprising the steps of: (a) extruding a web having a first surface and a second surface from a slot die; then (b) passing the web around at least a portion of the periphery of a cooling roll such that the first surface of the web is in contact with the cooling roll; and then (c) passing the web between the cooling roll and a pressure roll that is parallel to and spaced from the cooling roll such that, along the line at which the cooling roll is closest to the pressure roll: (i) the first surface of an upstream portion of the web is in line contact with the cooling roll; (ii) the second surface of the upstream portion of the web is in line contact with the first surface of a downstream portion of the web; and (iii) the second surface of the downstream portion of the web is in line contact with the pressure roll.
Claim 2
Dependent Claim
167 words
A process for the production of plastic film, said process comprising the steps of: (a) extruding a web having a first surface and a second surface from a slot die; then (b) passing the web around at least a portion of the periphery of a cooling roll such that the first surface of the web is in contact with the cooling roll; and then (c) passing the web between the cooling roll and a pressure roll that is parallel to and spaced from the cooling roll such that, along the line at which the cooling roll is closest to the pressure roll: (i) the first surface of an upstream portion of the web is in line contact with the cooling roll; (ii) the second surface of the upstream portion of the web is in line contact with the first surface of a downstream portion of the web; and (iii) the second surface of the downstream portion of the web is in line contact with the pressure roll.
Claim 3
Dependent Claim
30 words
A process as recited in claim 1 and further comprising the step of separating the upstream portion of the web from the downstream portion of the web after step (c).
Claim 4
Dependent Claim
15 words
A process as recited in claim 1 wherein the pressure roll has an elastic surface.
Claim 5
Dependent Claim
18 words
A process as recited in claim 1 wherein the web has a thickness of less than 300 micrometers.
Claim 6
Independent Claim
138 words
A device for the production of plastic film, said device comprising: (a) a slot die for extrusion of a thermoplastic web having a first surface and a second surface; (b) a calendar stack placed downstream of said slot die, said calendar stack comprising a cooling roll and a pressure roll forming a nip; and (c) means for passing the web between said cooling roll and said pressure roll such that, in the nip: (i) the first surface of an upstream portion of the web is in line contact with the cooling roll; (ii) the second surface of the upstream portion of the web is in line contact with the first surface of a downstream portion of the web; and (iii) the second surface of the downstream portion of the web is in line contact with the pressure roll.
Claim 7
Independent Claim
138 words
A device for the production of plastic film, said device comprising: (a) a slot die for extrusion of a thermoplastic web having a first surface and a second surface; (b) a calendar stack placed downstream of said slot die, said calendar stack comprising a cooling roll and a pressure roll forming a nip; and (c) means for passing the web between said cooling roll and said pressure roll such that, in the nip: (i) the first surface of an upstream portion of the web is in line contact with the cooling roll; (ii) the second surface of the upstream portion of the web is in line contact with the first surface of a downstream portion of the web; and (iii) the second surface of the downstream portion of the web is in line contact with the pressure roll.
Claim 8
Dependent Claim
19 words
A device as recited in claim 5 wherein said pressure roll has a surface formed of an elastic material.
Claim 9
Dependent Claim
27 words
A device as recited in claim 5 wherein said means comprises a plurality of deflecting rolls placed axially parallel to said cooling roll and said pressure roll.
Claim 10
Dependent Claim
21 words
A device as recited in claim 7 wherein said deflecting rolls define a path for the web around said slot die.
Claim 11
Dependent Claim
51 words
A device as recited in claim 7 wherein: (a) said deflecting rolls define a path for the web on the side of said calendar stack opposite said slot die and (b) another deflecting roll is placed obliquely to said cooling roll between said calendar stack and the path for the web.
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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) | 1992-08-21 | 1993-02-20 | 1993-08-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-08-21 | 1997-02-20 | 1997-08-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-08-21 | 2001-02-20 | 2001-08-22 | $7700.00 | Window Closed / Lapsed |