US4925685A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Lid for food trays
Assignee: DuPont Canada Inc
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Filing: 1988-03-04
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Granted: 1990-05-15
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Expires: 2008-03-04
Abstract
Abstract The present invention provides a tray having a floor, walls attached thereto, said walls having a rim distal to the floor, said tray having food placed therein and an amorphous polyester, e.g. polyethylene terephthalate, a partially crystalline polyester, e.g. polyethylene terephthalate, or amorphous nylon film stretched across the rim and extending down the outer portion of the wall adjacent to the rim in a vacuum-induced thermally-set crimp. The polyester or nylon may optionally be blended with a compatibilized polyolefin.
Inventors
- 👤 Ash K. Sahi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 16:16
CPC Classifications
B; B65; B65D; B65D81/00; B65D81/34; B65D81/3446; B65D81/3453
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
87 words
A tray having a floor, walls attached thereto, said walls having a rim distal to the floor, said tray having food placed therein and a film formed across the rim and extending down the outer portion of the wall adjacent to the rim in a vacuum-induced and thermally-set crimp, said film being selected from films of amorphous polyester, partially crystalline polyester and mixtures thereof; amorphous polyester, partially crystalline polyester and mixtures thereof admixed with a compatibilized polyolefin; and amorphous nylon and mixtures thereof with a compatibilized polyolefin.
Claim 2
Dependent Claim
87 words
A tray having a floor, walls attached thereto, said walls having a rim distal to the floor, said tray having food placed therein and a film formed across the rim and extending down the outer portion of the wall adjacent to the rim in a vacuum-induced and thermally-set crimp, said film being selected from films of amorphous polyester, partially crystalline polyester and mixtures thereof; amorphous polyester, partially crystalline polyester and mixtures thereof admixed with a compatibilized polyolefin; and amorphous nylon and mixtures thereof with a compatibilized polyolefin.
Claim 3
Dependent Claim
26 words
A tray according to claim 1 wherein the tray has an externally protruding lip at the rim and the film extends above and below the lip.
Claim 4
Dependent Claim
27 words
A tray according to claim 2 wherein the tray is shallow and the film extends down the outer sides of the walls and partially under the floor.
Claim 5
Dependent Claim
12 words
A tray according to claim 1 wherein the polyester is polyethylene terephthalate.
Claim 6
Dependent Claim
12 words
A tray according to claim 2 wherein the polyester is polyethylene terephthalate.
Claim 7
Dependent Claim
22 words
A tray according to claim 2 wherein the film is made from a mixture of an amorphous polyethylene terephthalate and an ionomer.
Claim 8
Dependent Claim
15 words
A tray according to claim 2 wherein the film is made from an amorphous nylon.
Claim 9
Dependent Claim
20 words
A tray according to claim 2 wherein an adhesive is applied between the lip of the tray and the film.
Claim 10
Dependent Claim
20 words
A tray according to claim 5 wherein an adhesive is applied between the lip of the tray and the film.
Claim 11
Dependent Claim
20 words
A tray according to claim 6 wherein an adhesive is applied between the lip of the tray and the film.
Claim 12
Dependent Claim
20 words
A tray according to claim 7 wherein an adhesive is applied between the lip of the tray and the film.
Claim 13
Dependent Claim
18 words
A tray according to claim 2 wherein the film is from 25 μm to 250 μm in thickness.
Claim 14
Dependent Claim
18 words
A tray according to claim 5 wherein the film is from 25 μm to 250 μm in thickness.
Claim 15
Dependent Claim
18 words
A tray according to claim 6 wherein the film is from 25 μm to 250 μm in thickness.
Claim 16
Dependent Claim
18 words
A tray according to claim 7 wherein the film is from 25 μm to 250 μm in thickness.
Claim 17
Dependent Claim
13 words
A tray according to claim 2 wherein the tray is made of nylon.
Claim 18
Dependent Claim
13 words
A tray according to claim 5 wherein the tray is made of nylon.
Claim 19
Dependent Claim
13 words
A tray according to claim 6 wherein the tray is made of nylon.
Claim 20
Dependent Claim
13 words
A tray according to claim 7 wherein the tray is made of nylon.
Claim 21
Dependent Claim
44 words
A tray according to claim 2 wherein the compatibilized olefin-based polymer is selected from copolymers of ethylene and unsaturated carboxylic acid, copolymers of ethylene and unsaturated carboxylic acid ester monomers, hydrocarbon alpha-olefins grafted with unsaturated carboxylic acids, and hydrocarbon alpha-olefins grafted with unsaturated anhydrides.
Claim 22
Dependent Claim
34 words
A tray according to claim 19 wherein the compatibilized polyolefin material is selected from ethylene/vinyl acetate copolymers, ethylene/methylacrylate copolymers, ethylene/ethylacrylate copolymers, ethylene/n-butylacrylate copolymers, ethylene/methacrylate copolymers, ethylene/methacrylic acid copolymer and partially neutralized ethylene/methacrylic acid copolymers.
Claim 23
Dependent Claim
70 words
A tray according to claim 19 wherein the compatibilized polyolefin material is selected from ethylene/acrylate ester copolymer grafted with an unsaturated carboxylic acid, ethylene/acrylate ester copolymers grafted with an unsaturated anhydride, ethylene/C 4 to C 10 alpha-olefin copolymers grafted with unsaturated carboxylic acids, ethylene/C 4 to C 10 alpha-olefin copolymers grafted with an unsaturated anhydride, ethylene homopolymers grafted with unsaturated carboxylic acids, and ethylene homopolymers grafted with an unsaturated anhydride.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-05-14 | 1993-11-13 | 1994-05-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-05-14 | 1997-11-13 | 1998-05-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-05-14 | 2001-11-13 | 2002-05-15 | $7700.00 | Window Closed / Lapsed |