US4287147A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Multilayer film manufacture utilizing scrap resin
Assignee: Mobil Oil AS
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Filing: 1980-04-25
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Granted: 1981-09-01
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Expires: 2000-04-25
Abstract
Abstract A novel system for producing film by extruding and/or casting at least two layers of resin, such as polyacrylonitrile homopolymer or interpolymers. The system provides for co-extruding a continuous multi-layer film with contiguous or tandem dies from a first supply of homogeneous resin solution and a second supply of non-homogeneous redissolved resin scrap. The film may be cast onto a smooth cooled drum surface to form substantially continuous adjacent layers from two or more resin supplies. By stripping the film from the drum as a continuous film strip and stretching the film an oriented structure is provided. Scrap resin, such as selvage trimmed from the stretched film or mill scrap, is comminuted and redissolved in solvent for recycle to the second supply of the extrusion step. The homogeneous layer prevents film disruption by inhomogeneities present in the contiguous layer containing redissolved scrap, which might cause localized stresses in the film and discontinuities during stretching.
Inventors
- 👤 Gordon P. Hungerford
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 19:27
CPC Classifications
B; B32; B32B; B32B27/00; B32B27/06; B32B27/08; B29; B29B; B29B17/00; B29B17/0005; B29B17/0026; B29B17/0042; B29C; B29C48/00; B29C48/03; B29C48/07; B29C48/08; B29C48/25; B29C48/88; B29C48/911; B29C48/9135; B29C48/914; B32B27/30; B32B27/302; B32B27/308; B32B38/00; B32B38/0012; B32B2038/0028; B32B2264/00; B32B2264/02; B32B2264/0214; B32B2264/025; B32B2305/00; B32B2305/70; B32B2307/00; B32B2307/50; B32B2307/514; Y; Y02; Y02W; Y02W30/00; Y02W30/50; Y02W30/62; Y10; Y10S; Y10S425/00; Y10S425/046
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
131 words
A method for producing multilayer film having at least one layer containing recycled polyacrylonitrile which comprises the steps of co-extruding a continuous multilayer film from a first supply of substantially homogeneous polyacrylonitrile resin solution and a second supply containing non-homogeneous redissolved polyacrylonitrile resin scrap; casting said multilayer film onto a smooth cooled drum surface to form substantially continuous adjacent layers from said first supply and said second supply; stripping said multilayer film from said drum as a self-supporting continuous film strip; removing at least a portion of the solvent from said multilayer film; stretching said multilayer film to provide an oriented structure; trimming excess polyacrylonitrile resin from said stretched film as selvage resin; comminuting said selvage resin; and redissolving said comminuted selvage resin in solvent for recycle to said second supply.
Claim 2
Independent Claim
131 words
A method for producing multilayer film having at least one layer containing recycled polyacrylonitrile which comprises the steps of co-extruding a continuous multilayer film from a first supply of substantially homogeneous polyacrylonitrile resin solution and a second supply containing non-homogeneous redissolved polyacrylonitrile resin scrap; casting said multilayer film onto a smooth cooled drum surface to form substantially continuous adjacent layers from said first supply and said second supply; stripping said multilayer film from said drum as a self-supporting continuous film strip; removing at least a portion of the solvent from said multilayer film; stretching said multilayer film to provide an oriented structure; trimming excess polyacrylonitrile resin from said stretched film as selvage resin; comminuting said selvage resin; and redissolving said comminuted selvage resin in solvent for recycle to said second supply.
Claim 3
Dependent Claim
17 words
The method of claim 1, wherein said first supply comprises a dimethyl sulfoxide solution of acrylonitrile homopolymer.
Claim 4
Dependent Claim
18 words
The method of claim 2 wherein said homopolymer comprises about 30% to 40% by weight of said solution.
Claim 5
Dependent Claim
13 words
The method of claim 1 wherein said multilayer film consists essentially of polyacrylontrile.
Claim 6
Dependent Claim
18 words
The method of claim 1 wherein said multilayer film comprises at least one co-extruded layer of thermoplastic resin.
Claim 7
Dependent Claim
18 words
The method of claim 5 wherein said co-extruded thermoplastic resin comprises an interpolymer comprising acrylonitrile and butylacrylate units.
Claim 8
Dependent Claim
132 words
A film production system comprising multiple die means for extruding at least two streams of resinous material in laminar flow relationship; means for soldifiying said resinous materials to form a substantially uniform multilayered film; means for orienting the soldified resinous materials by stretching the film; means for drying the oriented film and removing volatile matter; cutting means for producing a finished film product and producing resin scrap; means for comminuting the resin scrap; means for dissolving the resin scrap to form a non-homogeneous resin scrap material; means for recycling the dissolved scrap material to the multiple die means for re-extrusion as a discrete layer; and means for feeding a homogeneous resin material to said multiple die means, thereby forming contiguous layers of the non-homogeneous and homogeneous resin materials having good film integrity.
Claim 9
Dependent Claim
132 words
A film production system comprising multiple die means for extruding at least two streams of resinous material in laminar flow relationship; means for soldifiying said resinous materials to form a substantially uniform multilayered film; means for orienting the soldified resinous materials by stretching the film; means for drying the oriented film and removing volatile matter; cutting means for producing a finished film product and producing resin scrap; means for comminuting the resin scrap; means for dissolving the resin scrap to form a non-homogeneous resin scrap material; means for recycling the dissolved scrap material to the multiple die means for re-extrusion as a discrete layer; and means for feeding a homogeneous resin material to said multiple die means, thereby forming contiguous layers of the non-homogeneous and homogeneous resin materials having good film integrity.
Claim 10
Dependent Claim
19 words
The film production system of claim 7 which includes means for removing solvent from said multilayer film following solidification.
Claim 11
Dependent Claim
16 words
The film production system of claim 8 which includes a counter-current washing means for solvent removal.
Claim 12
Dependent Claim
18 words
The film production system of claim 7 wherein said comminuting means comprises chopping means for producing flaked film.
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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) | 1984-08-31 | 1985-03-02 | 1985-09-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-08-31 | 1989-03-02 | 1989-09-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-08-31 | 1993-03-02 | 1993-09-01 | $7700.00 | Window Closed / Lapsed |