Patent US4240993A successfully refreshed from Google Patents.
US4240993A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Multi-layer film containing a layer of crosslinked ethylene/vinyl alcohol copolymer
Assignee: WR Grace and Co Conn
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Filing: 1978-08-07
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Granted: 1980-12-23
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Expires: 1998-08-07
Abstract
Abstract A multi-layer film having a crosslinked layer of an olefin vinyl alcohol copolymer is produced by providing a substrate layer and a layer of a copolymer of an olefin and a vinyl ester. The multi-layer structure is crosslinked preferably by irradiation and then hydrolyzed to convert the olefin/vinyl ester copolymer into a copolymer of the olefin and vinyl alcohol. The thus produced structure may be incorporated into a further film combination by extrusion coating additional layers. The multi-layer structure may be oriented to produce a heat shrinkable film for use as a packaging material.
Inventors
- 👤 Joseph Z. Sun
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 21:50
CPC Classifications
B; B32; B32B; B32B27/00; B32B27/30; B29; B29C; B29C61/00; B29C61/06; B29C61/0608; B29C61/0616; B32B27/06; B32B27/08; B32B37/00; B32B37/14; B32B37/16; B32B37/20; B32B37/203; C; C08; C08J; C08J7/00; C08J7/12; B32B38/00; B32B2038/0052; B32B2038/0076; B32B2305/00; B32B2305/72; B32B2310/00; B32B2310/08; B32B2310/0806; B32B2310/0831; B32B2310/085; B32B2310/0875; B32B2310/0887; B32B2553/00; C08J2323/00; C08J2323/02; C08J2323/04; C08J2323/08; Y; Y10; Y10T; Y10T428/00; Y10T428/31504; Y10T428/31855; Y10T428/31909; Y10T428/31928
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
83 words
A process for producing a multi-layer film, comprising the steps of: providing a multi-layer structure having a substrate layer having a flexibility suitable for packaging material and a precursor layer of a copolymer of an olefin and a vinyl ester; crosslinking said precursor layer to produce a crosslinked precursor layer with at least one crosslink per weight average molecule; hydrolyzing said crosslinked precursor layer to produce a multi-layer film having a substrate layer and a copolymer layer of an olefin and vinyl alcohol.
Claim 2
Dependent Claim
83 words
A process for producing a multi-layer film, comprising the steps of: providing a multi-layer structure having a substrate layer having a flexibility suitable for packaging material and a precursor layer of a copolymer of an olefin and a vinyl ester; crosslinking said precursor layer to produce a crosslinked precursor layer with at least one crosslink per weight average molecule; hydrolyzing said crosslinked precursor layer to produce a multi-layer film having a substrate layer and a copolymer layer of an olefin and vinyl alcohol.
Claim 3
Dependent Claim
21 words
The process according to claim 1 wherein said olefin is selected from the group consisting of ethylene, propylene, butene-1 and butylene.
Claim 4
Dependent Claim
27 words
The process according to claim 1 wherein said vinyl ester is a vinyl ester of an aliphatic mono basic acid having from 1 to 8 carbon atoms.
Claim 5
Dependent Claim
13 words
The process according to claim 3 wherein said vinyl ester is vinyl acetate.
Claim 6
Dependent Claim
18 words
The process according to claim 1 wherein said precursor copolymer is a copolymer of ethylene and vinyl acetate.
Claim 7
Dependent Claim
37 words
The process according to claim 1 wherein said step of providing is carried out by coextruding said substrate layer and said precursor layer in tubular form with said substrate layer on the interior of said tubular form.
Claim 8
Dependent Claim
21 words
The process according to claim 1 wherein said step of crosslinking is carried out by subjecting the precursor layer to radiation.
Claim 9
Dependent Claim
26 words
The process according to claim 7 wherein said step of hydrolyzing is carried out by contacting said crosslinked precursor with a primary alcohol and a cataylst.
Claim 10
Dependent Claim
18 words
The process according to claim 1 wherein said substrate layer is a polymer or copolymer of an olefin.
Claim 11
Dependent Claim
22 words
The process according to claim 9 wherein said olefin polymer or copolymer is simultaneously crosslinked with the crosslinking of said precursor layer.
Claim 12
Dependent Claim
17 words
The process according to claim 1 further comprising orienting said multilayer structure after said step of hydrolyzing.
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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) | 1983-12-23 | 1984-06-23 | 1984-12-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-12-23 | 1988-06-23 | 1988-12-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-12-23 | 1992-06-23 | 1992-12-23 | $7700.00 | Window Closed / Lapsed |