US4657811A
Expired / Lapsed
US
⏱️ 0.0 years remaining
High performance three layer polyolefin film
Assignee: Mobil Oil AS
•
Filing: 1985-05-23
•
Granted: 1987-04-14
•
Expires: 2005-05-23
Abstract
Abstract There is provided a three-ply plastic film prepared by a sandwich foam, blown film coextrusion process. The outer skin layers are composed of high performance polyolefins, such as linear low density polyethylene. The foamed middle layer imparts to the film improved structural integrity and stiffness, an independent tear mechanism for the skin layers, and improved TD tear strength.
Inventors
- 👤 Dana M. Boyd
- 👤 Edward A. Colombo
- 👤 William H. Lashway
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 01:02
CPC Classifications
B; B32; B32B; B32B27/00; B32B27/32; B32B27/322; B32B27/06; B32B27/08; B65; B65D; B65D31/00; B65D31/02; Y; Y10; Y10T; Y10T428/00; Y10T428/249921; Y10T428/249953; Y10T428/249987; Y10T428/249988; Y10T428/249991; Y10T428/249992; Y10T428/249993; Y10T428/31504; Y10T428/31855; Y10T428/31909; Y10T428/31913
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
138 words
A three-ply plastic film comprising: (i) outermost and innermost skin layers manufactured from linear low density polyethylene or linear high density polyethylene, said skin layers being of equal or different thickness, said skin layers each having a thickness of between about 0.25 and about 0.50 mils; and (ii) a middle foamed thermoplastic layer having a density of at least 25% less than the density of the corresponding unfoamed version of said layer, the thickness of said foamed layer being between about 0.25 and about 1.5 mils, the film exhibiting an independent tearing mechanism for each of the skin layers and substantially improved TD tear strength as compared to a substantially identical comparative three-ply plastic film comprising outermost and innermost skin layers manufactured from linear low density polyethylene or linear high density polyethylene and a middle non-foamed thermoplastic layer.
Claim 2
Dependent Claim
138 words
A three-ply plastic film comprising: (i) outermost and innermost skin layers manufactured from linear low density polyethylene or linear high density polyethylene, said skin layers being of equal or different thickness, said skin layers each having a thickness of between about 0.25 and about 0.50 mils; and (ii) a middle foamed thermoplastic layer having a density of at least 25% less than the density of the corresponding unfoamed version of said layer, the thickness of said foamed layer being between about 0.25 and about 1.5 mils, the film exhibiting an independent tearing mechanism for each of the skin layers and substantially improved TD tear strength as compared to a substantially identical comparative three-ply plastic film comprising outermost and innermost skin layers manufactured from linear low density polyethylene or linear high density polyethylene and a middle non-foamed thermoplastic layer.
Claim 3
Dependent Claim
16 words
A three-ply plastic film of claim 1 having an overall thickness of 2.5 mils or less.
Claim 4
Dependent Claim
16 words
A three-ply plastic film of claim 2 having an overall thickness of 1.5 mils or less.
Claim 5
Dependent Claim
22 words
A three-ply plastic film of claim 3, wherein said skin layers each have a thickness of between about 0.30 and 0.40 mils.
Claim 6
Dependent Claim
21 words
A three-ply plastic film of claim 4, wherein said foamed layer has a thickness of between about 0.5 and 1.0 mils.
Claim 7
Dependent Claim
22 words
A three-ply plastic film of claim 5, wherein said foamed layer has a void volume of between about 30% and about 75%.
Claim 8
Dependent Claim
48 words
A three-ply plastic film of claim 6 wherein said foamed thermoplastic layer is manufactured from a material selected from the group consisting of linear high density polyethylene, linear low density polyethylene, non-linear high density polyethylene, non-linear low density polyethylene, polypropylene, polybutylene, ethylene vinyl acetate copolymers and polyethylene terephthalate.
Claim 9
Dependent Claim
19 words
A three-ply plastic film of claim 7 wherein said foamed thermoplastic layer is manufactured from non-linear low density polyethylene.
Claim 10
Dependent Claim
18 words
A three-ply plastic film of claim 8 wherein said skin layers are manufactured from linear low density polyethylene.
Claim 11
Independent Claim
125 words
A method for improving the handleability and strength characteristics of a plastic film containing high performance polyolefin comprising interposing a foamed thermoplastic layer between two high performance polyolefin skin layers by a blown film coextrusion process, thereby forming a three-ply plastic film comprised of: (i) outermost and innermost skin layers manufactured from linear low density polyethylene or linear high density polyethylene, said skin layers being of equal or different thickness, said skin layers each having a thickness of between about 0.25 and about 0.50 mils; and (ii) a middle foamed thermoplastic layer having a density of at least 25% less than the density of the corresponding unfoamed version of said layer, the thickness of said foamed layer being between about 0.25 and about 1.5 mils.
Claim 12
Independent Claim
125 words
A method for improving the handleability and strength characteristics of a plastic film containing high performance polyolefin comprising interposing a foamed thermoplastic layer between two high performance polyolefin skin layers by a blown film coextrusion process, thereby forming a three-ply plastic film comprised of: (i) outermost and innermost skin layers manufactured from linear low density polyethylene or linear high density polyethylene, said skin layers being of equal or different thickness, said skin layers each having a thickness of between about 0.25 and about 0.50 mils; and (ii) a middle foamed thermoplastic layer having a density of at least 25% less than the density of the corresponding unfoamed version of said layer, the thickness of said foamed layer being between about 0.25 and about 1.5 mils.
Claim 13
Dependent Claim
19 words
A method of claim 10, wherein said three-ply plastic film has an overall thickness of 2.5 mils or less.
Claim 14
Dependent Claim
19 words
A method of claim 11, wherein said three-ply plastic film has an overall thickness of 1.5 mils or less.
Claim 15
Dependent Claim
22 words
A method of claim 12, wherein each of said skin layers has a thickness of between about 0.30 and about 0.40 mils.
Claim 16
Dependent Claim
19 words
A method of claim 13, wherein said foamed layer has a thickness of between about 0.5 and 1.0 mils.
Claim 17
Dependent Claim
20 words
A method of claim 14, wherein said foamed layer has a void volume of between about 30% and about 75%.
Claim 18
Dependent Claim
46 words
A method of claim 15 wherein said foamed thermoplastic layer is manufactured from a material selected from the group consisting of linear high density polyethylene, linear low density polyethylene, non-linear high density polyethylene, non-linear low density polyethylene, polypropylene, polybutylene, ethylene vinyl acetate copolymers and polyethylene terephthalate.
Claim 19
Dependent Claim
17 words
A method of claim 16 wherein said foamed thermoplastic layer is manufactured from non-linear low density polyethylene.
Claim 20
Dependent Claim
16 words
A method of claim 17 wherein said skin layers are manufactured from linear low density polyethylene.
Claim 21
Dependent Claim
55 words
A three-ply plastic film of claim 9 having a thickness of 2.61 mils wherein the two skin layers are manufactured from low pressure linear low density polyethylene of 0.920 g/cc density and melt index of 1.0, and the middle layer is manufactured from high pressure polyethylene of 0.920 g/cc density and melt index of 2.0.
Claim 22
Dependent Claim
55 words
A three-ply plastic film of claim 9 having a thickness of 1.57 mils wherein the two skin layers are manufactured from low pressure linear low density polyethylene of 0.920 g/cc density and melt index of 1.0, and the middle layer is manufactured from high pressure polyethylene of 0.920 g/cc density and melt index of 2.0.
Claim 23
Dependent Claim
58 words
A method of claim 18 wherein the three-ply plastic film has a thickness of 2.61 mils and the two skin layers are manufactured from low pressure linear low density polyethylene of 0.920 g/cc density and melt index of 1.0, and the middle layer is manufactured from high pressure polyethylene of 0.920 g/cc density and melt index of 2.0.
Claim 24
Dependent Claim
58 words
A method of claim 18 wherein the three-ply plastic film has a thickness of 1.57 mils and the two skin layers are manufactured from low pressure linear low density polyethylene of 0.290 g/cc density and melt index of 1.0, and the middle layer is manufactured from high pressure polyethylene of 0.920 g/cc density and melt index of 2.0.
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) | 1990-04-13 | 1990-10-13 | 1991-04-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-04-13 | 1994-10-13 | 1995-04-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-04-13 | 1998-10-13 | 1999-04-14 | $7700.00 | Window Closed / Lapsed |