Patent US4310485A successfully refreshed from Google Patents.
US4310485A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of improving the flatness of compression-rolled plastic film
Assignee: Printpack Illinois Inc
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Filing: 1980-09-26
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Granted: 1982-01-12
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Expires: 2000-09-26
Abstract
Abstract The flatness of compression-rolled plastic film is improved by passing the film under tension over heated rolls, stretching the heated film, setting the stretched film by passing it over a tempering roll, and then cooling the set film by passing it over a cooling roll.
Inventors
- 👤 Rikhard C. Dauber
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 15:43
CPC Classifications
B; B29; B29C; B29C55/00; B29C55/02; B29C55/04; B29C55/06; B29C53/00; B29C53/16
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
123 words
A method of improving the flatness of compression-rolled plastic film comprising (a) passing the compression-rolled film under tension over the surface of a roll while heating the film on the roll to an elevated temperature below the melting point of the plastic film, (b) passing the heated film through the nip between a driven roll and a nip roll such that the film is stretched at least three percent in the machine direction, (c) while maintaining the film under tension, passing the stretched film over a tempering roll to set the film on the roll, and (d) while still maintaining the film under tension, passing the set film over a cooling roll to cool the film to a temperature which approaches ambient temperature.
Claim 2
Independent Claim
123 words
A method of improving the flatness of compression-rolled plastic film comprising (a) passing the compression-rolled film under tension over the surface of a roll while heating the film on the roll to an elevated temperature below the melting point of the plastic film, (b) passing the heated film through the nip between a driven roll and a nip roll such that the film is stretched at least three percent in the machine direction, (c) while maintaining the film under tension, passing the stretched film over a tempering roll to set the film on the roll, and (d) while still maintaining the film under tension, passing the set film over a cooling roll to cool the film to a temperature which approaches ambient temperature.
Claim 3
Dependent Claim
24 words
The method of claim 1 wherein the tension exerted on the film is sufficient to prevent the film from contracting in the machine direction.
Claim 4
Dependent Claim
25 words
The method of claim 2 wherein the film is heated by means of the roll over which the film is passed while it is heated.
Claim 5
Dependent Claim
27 words
The method of claim 3 wherein the film is heated to a temperature between about 5° and 40° C. less than the melting point of the film.
Claim 6
Dependent Claim
22 words
The method of claim 4 where the dwell time of the film on the tempering roll is at least about 0.05 second.
Claim 7
Dependent Claim
25 words
The method of claim 5 wherein the temperature of the film drops less than 40° C. as it is being set on the tempering roll.
Claim 8
Dependent Claim
21 words
The method of claim 6 wherein the film is cooled on the cooling roll to a temperature below about 70° C.
Claim 9
Dependent Claim
11 words
The method of claim 7 wherein the film is a polyolefin.
Claim 10
Dependent Claim
35 words
The method of claim 8 wherein the film is polyethylene, polypropylene, or a copolymer of ethylene or propylene with another ethylenically unsaturated monomer wherein the ethylene or propylene content is at least fifty mole percent.
Claim 11
Dependent Claim
26 words
The method of claim 1 wherein the temperature of the film drops from 0° to 40° C. as it is being set on the tempering roll.
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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) | 1985-01-11 | 1985-07-13 | 1986-01-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-01-11 | 1989-07-13 | 1990-01-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-01-11 | 1993-07-13 | 1994-01-12 | $7700.00 | Window Closed / Lapsed |