US4440824A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Thermoformable coextruded multilayered structure
Assignee: Composite Container Corp
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Filing: 1982-10-04
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Granted: 1984-04-03
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Expires: 2002-10-04
Abstract
Abstract A multilayer thermoplastic sheet suitable for thermoforming into containers, the sheet being simply and expeditiously prepared and provided with consistent and reliable bonds between layers in a single process step by coextruding a polyolefin having moisture barrier properties with a high impact polystyrene layer, to provide heat sealability, a printable surface, and quick and inexpensive thermoforming for the multilayer sheet.
Inventors
- 👤 Laszlo J. Bonis
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 15:19
CPC Classifications
B; B32; B32B; B32B27/00; B32B27/06; B32B27/08; B32B2250/00; B32B2250/40; B32B2323/00; B32B2323/10; B32B2325/00; Y; Y10; Y10T; Y10T428/00; Y10T428/13; Y10T428/1352; Y10T428/1386; Y10T428/24; Y10T428/24942; Y10T428/2495; Y10T428/24967; Y10T428/24975; Y10T428/28; Y10T428/2813; Y10T428/2817; Y10T428/2826; Y10T428/31504; Y10T428/31855; Y10T428/31909; Y10T428/31913; Y10T428/31917; Y10T428/31928
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
74 words
A coextruded multilayered structure comprising a layer of a polyolefin of the group of polyethylene and polypropylene, to provide effective moisture barrier properties, a layer of high impact polystyrene, said polystyrene layer providing a printable and heat sealable surface and thermoformability during manufacture, and an adhesive tie layer between said polystyrene and polyolefin layers, said tie layer consisting essentially of one of the group of ethylene-vinyl acetate copolymer and polyolefin with acrylic acid additive.
Claim 2
Dependent Claim
74 words
A coextruded multilayered structure comprising a layer of a polyolefin of the group of polyethylene and polypropylene, to provide effective moisture barrier properties, a layer of high impact polystyrene, said polystyrene layer providing a printable and heat sealable surface and thermoformability during manufacture, and an adhesive tie layer between said polystyrene and polyolefin layers, said tie layer consisting essentially of one of the group of ethylene-vinyl acetate copolymer and polyolefin with acrylic acid additive.
Claim 3
Dependent Claim
21 words
The structure of claim 1 wherein said polystyrene layer is made of a mixture of polystyrene and a rubber modifying plastomer.
Claim 4
Dependent Claim
40 words
The structure of claim 2 further comprising an adhesive tie layer and a polystyrene layer bonded to the other side of said polyolefin layer to result in a five-layer structure that has resistance to curling owing to the symmetrical structure.
Claim 5
Dependent Claim
25 words
The structure of claim 2 wherein said rubber modifying plastomer comprises radial butadiene/styrene teleblock copolymer to increase impact resistance and provide clarity for the structure.
Claim 6
Dependent Claim
22 words
The structure of claim 4 wherein there is 25-35% radial butadiene/styrene teleblock copolymer and about 65-75% crystal styrene in the polystyrene layer.
Claim 7
Dependent Claim
19 words
The structure of claim 1 wherein said adhesive tie layer includes ethylene-vinyl acetate copolymer with 12-28% vinyl acetate content.
Claim 8
Dependent Claim
12 words
The structure of claim 6 wherein said vinyl acetate content is 21-26%.
Claim 9
Dependent Claim
16 words
The structure of claim 1 wherein said layer of polyolefin is 2 to 15 mils thick.
Claim 10
Dependent Claim
32 words
The structure of claim 8 wherein said layer of polyolefin is 2 to 5 mils thick and said layer of high impact polystyrene is greater than or equal to 5 mils thick.
Claim 11
Dependent Claim
10 words
The structure of claim 1 wherein said polyolefin is polypropylene.
Claim 12
Dependent Claim
19 words
The structure of claim 1 wherein said polyolefin layer contains up to 5% fatty acid additive to provide clarity.
Claim 13
Dependent Claim
78 words
A composite thermoformed from a coextruded multilayered sheet comprising a layer of a polyolefin of the group of polyethylene and polypropylene to provide effective moisture barrier properties, a layer of high impact polystyrene, said polystyrene layer providing a printable and heat sealable surface and thermoformability during manufacture, and an adhesive tie layer between said polystyrene and polyolefin layers, said tie layer consisting essentially of one of the group of ethylene-vinyl acetate copolymer and polyolefin with acrylic acid additive.
Claim 14
Dependent Claim
78 words
A composite thermoformed from a coextruded multilayered sheet comprising a layer of a polyolefin of the group of polyethylene and polypropylene to provide effective moisture barrier properties, a layer of high impact polystyrene, said polystyrene layer providing a printable and heat sealable surface and thermoformability during manufacture, and an adhesive tie layer between said polystyrene and polyolefin layers, said tie layer consisting essentially of one of the group of ethylene-vinyl acetate copolymer and polyolefin with acrylic acid additive.
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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) | 1987-04-03 | 1987-10-03 | 1988-04-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-04-03 | 1991-10-03 | 1992-04-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-04-03 | 1995-10-03 | 1996-04-03 | $7700.00 | Window Closed / Lapsed |