US4364981A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Three layer film having a core layer of low pressure, low density polyethylene
Assignee: Ferranti International PLC
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Filing: 1981-06-03
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Granted: 1982-12-21
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Expires: 2001-06-03
Abstract
Abstract A flexible co-extruded three layer film comprising outer layers of high pressure, low density polyethylene and a core layer of low pressure, low density polyethylene. The film is produced by a blown film tubular extrusion process at conventional rates and temperature and yet is free of melt fracture even though the low pressure, low density polyethylene would otherwise exhibit melt fracture.
Inventors
- 👤 Jerome T. Horner
- 👤 John Anthony
- 👤 William A. Fraser
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 04:48
CPC Classifications
B; B29; B29C; B29C48/00; B29C48/03; B29C48/09; B29C48/10; B32; B32B; B32B27/00; B32B27/06; B32B27/08; B32B27/32; B29C48/16; B29C48/18; B29C48/21; B29C48/25; B29C48/30; B29C48/305; B29C48/307; B29C48/32; B29C48/335; B32B27/322; B29C48/07; B29C48/08; B32B2307/00; B32B2307/50; B32B2307/54; B32B2323/00; B32B2323/04; B32B2323/046; B32B2439/00; B32B2439/02; B32B2439/06; Y; Y10; Y10T; Y10T428/00; Y10T428/13; Y10T428/1334; Y10T428/24; Y10T428/24942; Y10T428/2495; Y10T428/24992; Y10T428/26; Y10T428/263; Y10T428/264; Y10T428/265; Y10T428/269; Y10T428/31504; Y10T428/31855; Y10T428/31909; Y10T428/31913
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
94 words
A flexible co-extruded three-layer film comprising outer layers of high pressure, low density, polyethylene and a core layer of low pressure, low density polyethylene, said film having been produced by a conventional blown film tubular extrusion process at a throughput rate of from about 4 to about 25 pounds per hour per inch of die at a process temperature of from about 350° F. to about 600° F., said film being characterized as free of melt fracture and having a tensile strength in the transverse direction of at least about 4.0 pounds per inch.
Claim 2
Dependent Claim
94 words
A flexible co-extruded three-layer film comprising outer layers of high pressure, low density, polyethylene and a core layer of low pressure, low density polyethylene, said film having been produced by a conventional blown film tubular extrusion process at a throughput rate of from about 4 to about 25 pounds per hour per inch of die at a process temperature of from about 350° F. to about 600° F., said film being characterized as free of melt fracture and having a tensile strength in the transverse direction of at least about 4.0 pounds per inch.
Claim 3
Dependent Claim
21 words
The film of claim 1, wherein the thickness of the outside layers are each from about 0.18 to about 0.35 mil.
Claim 4
Dependent Claim
17 words
The film of claim 1, wherein the ratio of the thicknesses of the respective layers is 1:3:1.
Claim 5
Dependent Claim
18 words
The film of claim 1, wherein the overall film thickness is from about 1.0 to about 3.0 mils.
Claim 6
Dependent Claim
14 words
The film of claim 1, wherein the overall film thickness is about 1.5 mils.
Claim 7
Dependent Claim
58 words
The film of claim 1, wherein the film tensile strength in the transverse direction is higher than the tensile strength in the transverse direction for a control three layer film in which the core layer is the same high pressure low density polyethylene as the outer layers, said control three layer film being otherwise identical to said film.
Claim 8
Dependent Claim
46 words
A bag formed from the film of claim 1 wherein the film has been produced at a throughput rate of from about 4 to about 20 pounds per hour per inch of die at a process temperature of from about 350° F. to about 470° F.
Claim 9
Dependent Claim
9 words
A bag formed from the film of claim 1.
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) | 1985-12-20 | 1986-06-21 | 1986-12-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-12-20 | 1990-06-21 | 1990-12-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-12-20 | 1994-06-21 | 1994-12-21 | $7700.00 | Window Closed / Lapsed |