US5225257A
Expired / Lapsed
US
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Fluorine treatment of stretch/cling films
Assignee: ExxonMobil Chemical Patents Inc
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Filing: 1992-06-04
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Granted: 1993-07-06
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Expires: 2012-06-04
Abstract
Abstract A thermoplastic film is provided which is especially suited for use in stretch/cling applications such as, for example, the bundling, packaging and unitizing of foods and other goods. The film comprises a cling layer comprising a polymer of at least ethylene and acrylate and a non-cling layer comprising a polyolefin. One or both surfaces of the film are partially fluorinated to substantially increase the film cling and inhibit blocking.
Inventors
- 👤 Patrick Brant
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 21:21
CPC Classifications
B; B32; B32B; B32B27/00; B32B27/06; B32B27/08; A; A22; A22C; A22C13/00; A22C13/0013; B32B27/30; B32B27/308; B32B27/32; A22C2013/002; A22C2013/0053; A22C2013/0059; B32B2310/00; B32B2323/00; B32B2323/04; B32B2323/046; B32B2439/00; B32B2439/70; Y; Y10; Y10T; Y10T428/00; Y10T428/13; Y10T428/1328; Y10T428/31504; Y10T428/3154; Y10T428/31855; Y10T428/31909; Y10T428/31913; Y10T428/31928; Y10T428/31935
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
67 words
A thermoplastic stretch film, comprising: a cling layer comprising a polymer of two or more monomers, wherein a first monomer comprises ethylene and a second monomer comprises an acrylate; and a non-cling layer comprising polyethylene or polypropylene, wherein a surface of at least one of said layers is partially fluorinated to a sufficient extent to substantially increase the cling and substantially inhibit the block of the film.
Claim 2
Dependent Claim
67 words
A thermoplastic stretch film, comprising: a cling layer comprising a polymer of two or more monomers, wherein a first monomer comprises ethylene and a second monomer comprises an acrylate; and a non-cling layer comprising polyethylene or polypropylene, wherein a surface of at least one of said layers is partially fluorinated to a sufficient extent to substantially increase the cling and substantially inhibit the block of the film.
Claim 3
Dependent Claim
21 words
The film of claim 1, wherein said fluorinated surface is formed by exposure of said surface to fluorine and to oxygen.
Claim 4
Dependent Claim
26 words
The film of claim 1, wherein said surface has a fluorine:carbon surface stoichiometry as determined by X-ray photoelectron spectroscopy of from about 0.001 to about 0.5.
Claim 5
Dependent Claim
16 words
The film of claim 3, wherein said fluorination stoichiometry is from about 0.01 to about 0.15.
Claim 6
Dependent Claim
24 words
The film of claim 1, wherein said surface has a oxygen:carbon surface stoichiometry as determined by X-ray photoelectron spectroscopy of at least about 0.10.
Claim 7
Dependent Claim
18 words
The film of claim 1, further comprising at least one core layer between said cling and non-cling layers.
Claim 8
Dependent Claim
14 words
The film of claim 6, wherein said core layer comprises linear low density polyethylene.
Claim 9
Dependent Claim
22 words
The film of claim 1, wherein said acrylate monomer comprises from about 2 to about 40 percent by weight of said polymer.
Claim 10
Dependent Claim
22 words
The film of claim 1, wherein said acrylate monomer comprises from about 24 to about 28 percent by weight of said polymer.
Claim 11
Dependent Claim
52 words
The film of claim 1, wherein said acrylate monomer comprises a compound of the formula: ##STR2## wherein R is selected from hydrogen or a hydrocarbon group having from 1 to about 22 carbon atoms and wherein R' is independently selected from a hydrocarbon group having from 1 to about 22 carbon atoms.
Claim 12
Dependent Claim
21 words
The film of claim wherein said acrylate is selected from the group consisting of methyl acrylate, ethyl acrylate and n-butyl acrylate.
Claim 13
Dependent Claim
11 words
The film of claim 1, wherein said acrylate comprises methyl acrylate.
Claim 14
Dependent Claim
24 words
The film of claim wherein said non-cling layer comprises isotactic polypropylene having a melt flow rate of from about 0.1 to about 300 dg/min.
Claim 15
Dependent Claim
34 words
The film of claim 1, wherein said non-cling layer comprises medium density polyethylene having a density from about 0.92 to about 0.95 g/cc and a melt index between about 0.5 to about 10 dg/min.
Claim 16
Dependent Claim
95 words
A thermoplastic stretch film, comprising: a cling layer of ethylene-methyl acrylate copolymer having a methyl acrylate content of from about 24% to about 28% by weight of said copolymer wherein said cling layer is essentially free of tackifying additive; and a non-cling layer comprising a polyolefin and having a partially fluorinated outer surface to substantially increase the I/O cling of the film, said fluorinated surface formed by exposure of said surface to fluorine and to air, wherein said surface has a fluorine:carbon surface stoichiometry as determined by XPS of from about 0.01 to about 0.15.
Claim 17
Dependent Claim
95 words
A thermoplastic stretch film, comprising: a cling layer of ethylene-methyl acrylate copolymer having a methyl acrylate content of from about 24% to about 28% by weight of said copolymer wherein said cling layer is essentially free of tackifying additive; and a non-cling layer comprising a polyolefin and having a partially fluorinated outer surface to substantially increase the I/O cling of the film, said fluorinated surface formed by exposure of said surface to fluorine and to air, wherein said surface has a fluorine:carbon surface stoichiometry as determined by XPS of from about 0.01 to about 0.15.
Claim 18
Dependent Claim
28 words
The film of claim 15, wherein said non-cling layer comprises high density polyethylene, medium density polyethylene, low density polyethylene, linear low density polyethylene, polypropylene or a blend thereof.
Claim 19
Dependent Claim
94 words
A process for producing a thermoplastic film having a cling layer opposite a second layer, comprising the steps of: coextruding a first polymer layer with a second polymer layer, said first polymer comprising two or more monomers, wherein a first monomer comprises ethylene and a second monomer comprises an acrylate, and said second polymer comprises polypropylene or polyethylene; and exposing one or both surfaces of said coextruded layers to fluorine and to oxygen to partially fluorinate and oxygenate said surface or surfaces to substantially increase I/O cling of the film and to inhibit block.
Claim 20
Dependent Claim
94 words
A process for producing a thermoplastic film having a cling layer opposite a second layer, comprising the steps of: coextruding a first polymer layer with a second polymer layer, said first polymer comprising two or more monomers, wherein a first monomer comprises ethylene and a second monomer comprises an acrylate, and said second polymer comprises polypropylene or polyethylene; and exposing one or both surfaces of said coextruded layers to fluorine and to oxygen to partially fluorinate and oxygenate said surface or surfaces to substantially increase I/O cling of the film and to inhibit block.
Claim 21
Dependent Claim
23 words
The process of claim 17 wherein said exposure step is effective to obtain a fluorine:carbon surface stoichiometry from about 0.001 to about 0.5.
Claim 22
Dependent Claim
32 words
A bundled, packaged or unitized article or plurality of articles, comprising: the article or plurality of articles having the thermoplastic film of claim 1 stretch-wrapped around said article or plurality of articles.
Claim 23
Dependent Claim
29 words
A method for the surface protection of an article, comprising the step of: covering the surface to be protected on the article with the thermoplastic film of claim 1.
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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) | 1996-07-05 | 1997-01-04 | 1997-07-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-07-05 | 2001-01-04 | 2001-07-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-07-05 | 2005-01-04 | 2005-07-06 | $7700.00 | Window Closed / Lapsed |