US4297415A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Heat-sealable polypropylene films
Assignee: British Cellophane Ltd
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Filing: 1979-08-23
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Granted: 1981-10-27
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Expires: 1999-08-23
Abstract
Abstract A heat-sealable oriented polypropylene film comprising a base oriented polypropylene film having on one surface a layer of a random propylene/ethylene copolymer (ethylene content 2-6% by weight) and on the other surface a predominantly linear random copolymer of ethylene and a further alpha olefin having at least three carbon atoms per molecule (for example propylene and butene-1) the further alpha olefin content being 6-40% by weight. The film is particularly useful for packaging merchandise on horizontal form-fill-seal packaging machines.
Inventors
- 👤 Herbert J. Ward
- 👤 Derek J. Dobbie
- 👤 Brian Lyall
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 11:56
CPC Classifications
B; B32; B32B; B32B27/00; B32B27/32; B32B27/06; B32B27/08; B32B27/322; C; C08; C08J; C08J7/00; C08J7/04; C08J7/0427; C09; C09J; C09J123/00; C09J123/02; C09J123/16; B32B2250/00; B32B2250/24; B32B2250/242; B32B2272/00; B32B2307/00; B32B2307/30; B32B2307/31; B32B2307/50; B32B2307/514; B32B2439/00; B32B2439/40; C08J2323/00; C08J2323/02; C08J2323/10; C08J2323/12; C08J2423/00; C08L; C08L2666/00; C08L2666/02; C08L2666/04; Y; Y10; Y10S; Y10S428/00; Y10S428/91; Y10T; Y10T428/00; Y10T428/28; Y10T428/2813; Y10T428/2817; Y10T428/2826; Y10T428/31504; Y10T428/31855; Y10T428/31909; Y10T428/31913; Y10T428/31938
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
77 words
A heat-sealable oriented polypropylene film comprising a base film of oriented polypropylene film having on one surface a layer of a random propylene/ethylene copolymer in which the ethylene content lies in the range between 2% and 6% by weight and on the other surface a predominantly linear random copolymer of ethylene and between 6% and 40% by weight of the random copolymer of at least one further alpha olefin having at least three carbon atoms per molecule.
Claim 2
Dependent Claim
77 words
A heat-sealable oriented polypropylene film comprising a base film of oriented polypropylene film having on one surface a layer of a random propylene/ethylene copolymer in which the ethylene content lies in the range between 2% and 6% by weight and on the other surface a predominantly linear random copolymer of ethylene and between 6% and 40% by weight of the random copolymer of at least one further alpha olefin having at least three carbon atoms per molecule.
Claim 3
Dependent Claim
32 words
A polypropylene film as claimed in claim 1 in which amount of the further alpha olefin in the predominantly linear random copolymer lies in the range between 10% and 35% by weight.
Claim 4
Dependent Claim
16 words
A polypropylene film as claimed in claim 1 in which the further alpha olefin is propylene.
Claim 5
Dependent Claim
16 words
A polypropylene film as claimed in claim 1 in which the further alpha olefin is butene-1.
Claim 6
Independent Claim
96 words
A method of the manufacture of a heat-sealable oriented polypropylene film comprising applying to one surface of a base polypropylene film a layer of a random propylene/ethylene copolymer in which the ethylene content lies in the range between 2% and 6% by weight and to the other surface a predominantly linear random copolymer of ethylene and between 6% and 40% by weight of the random copolymer of at least one further alpha olefin having at least three carbon atoms per molecule, bringing the combination to a stretch orientatable condition and stretching in at least one direction.
Claim 7
Independent Claim
96 words
A method of the manufacture of a heat-sealable oriented polypropylene film comprising applying to one surface of a base polypropylene film a layer of a random propylene/ethylene copolymer in which the ethylene content lies in the range between 2% and 6% by weight and to the other surface a predominantly linear random copolymer of ethylene and between 6% and 40% by weight of the random copolymer of at least one further alpha olefin having at least three carbon atoms per molecule, bringing the combination to a stretch orientatable condition and stretching in at least one direction.
Claim 8
Dependent Claim
65 words
A method as claimed in claim 5 in which the layer of the propylene/ethylene copolymer and the layer of the copolymer of ethylene and at least one further alpha olefin are supplied to the base polypropylene film during co-extrusion of a melt of the copolymers and the polypropylene through a slot or annular orifice die following by quenching prior to stretching under stretch orientatable conditions.
Claim 9
Dependent Claim
34 words
A method as claimed in claim 5 in which the amount of the further alpha olefin in the predominantly linear copolymer lies in the range between 10% and 35% by weight of the copolymer.
Claim 10
Dependent Claim
15 words
A method as claimed in claim 5 in which the further alpha olefin is propylene.
Claim 11
Dependent Claim
15 words
A method as claimed in claim 5 in which the further alpha olefin is butene-1.
References Cited (Backward Citations)
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Cited
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Cited
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Cited
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Cited
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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) | 1984-10-26 | 1985-04-27 | 1985-10-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-10-26 | 1989-04-27 | 1989-10-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-10-26 | 1993-04-27 | 1993-10-27 | $7700.00 | Window Closed / Lapsed |