US4357191A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Laminar thermoplastic film constructions
Assignee: Pactiv LLC
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Filing: 1981-09-03
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Granted: 1982-11-02
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Expires: 2001-09-03
Abstract
Abstract Laminar thermoplastic film constructions comprising a layer of low density polyethylene bonded to a layer of a dissimilar polymer blend comprising high density polyethylene and polyethylene copolymers. In particular such copolymers comprise polyethylene copolymerized with another alpha olefin containing from about 3 up to about 15 carbon atoms. Such copolymers are also characterized by being linear, low density polymers having densities which are below about 0.94 grams/cc.
Inventors
- 👤 Edward M. Bullard
- 👤 Gregory M. Smith
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 19:55
CPC Classifications
B; B32; B32B; B32B27/00; B32B27/32; B29; B29C; B29C48/00; B29C48/001; B29C48/0013; B29C48/0015; B29C48/03; B29C48/09; B29C48/16; B29C48/18; B29C48/21; B32B27/06; B32B27/08; B32B2323/00; B32B2323/04; B32B2323/043; B32B2323/046; Y; Y10; Y10T; Y10T428/00; Y10T428/24; Y10T428/24942; Y10T428/31504; Y10T428/31855; Y10T428/31909; Y10T428/31913; Y10T428/31917
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
136 words
A method of forming a laminar film structure comprising, coaxially coextruding in a blown film process from concentric tubular die orifices separate molten streams of: (a) at least one layer comprising a general purpose low density polyethylene resin with; (b) a second thinner layer comprising a resinous blend of (1) a high density polyethylene and (2) a linear low density polyethylene-alpha-olefin copolymer, wherein said blend contains a major amount of said copolymer; merging said streams outside of said die orifices; and subjecting said coextruded tubular streams to an internal pressure trapped within the tube so as to effect a blow-up ratio of from about 1.5:3.0:1 and thereafter cooling the molten resins, said low density polyethylene having a thickness on the order of from about 65% up to about 85% of the overall thickness of said laminate.
Claim 2
Independent Claim
136 words
A method of forming a laminar film structure comprising, coaxially coextruding in a blown film process from concentric tubular die orifices separate molten streams of: (a) at least one layer comprising a general purpose low density polyethylene resin with; (b) a second thinner layer comprising a resinous blend of (1) a high density polyethylene and (2) a linear low density polyethylene-alpha-olefin copolymer, wherein said blend contains a major amount of said copolymer; merging said streams outside of said die orifices; and subjecting said coextruded tubular streams to an internal pressure trapped within the tube so as to effect a blow-up ratio of from about 1.5:3.0:1 and thereafter cooling the molten resins, said low density polyethylene having a thickness on the order of from about 65% up to about 85% of the overall thickness of said laminate.
Claim 3
Dependent Claim
9 words
The method of claim 1 including collapsing said tube.
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) | 1985-11-01 | 1986-05-03 | 1986-11-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-11-01 | 1990-05-03 | 1990-11-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-11-01 | 1994-05-03 | 1994-11-02 | $7700.00 | Window Closed / Lapsed |