US4734324A
Expired / Lapsed
US
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Heat sealable microporous polypropylene films
Assignee: Applied Extrusion Technologies Inc
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Filing: 1987-03-27
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Granted: 1988-03-29
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Expires: 2007-03-27
Abstract
Abstract This invention relates to a microporous film having a heat sealable layer on one or both sides thereof. The porosity and permeability of the microporous layer are retained despite the application of the heat seal layer.
Inventors
- 👤 David J. Hill
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 01:05
CPC Classifications
B; B32; B32B; B32B27/00; B32B27/32; B32B27/06; B32B27/08; B32B27/18; B32B27/20; B32B27/205; C; C08; C08J; C08J7/00; C08J7/04; C08J7/0427; B32B2250/00; B32B2250/02; B32B2250/24; B32B2250/242; B32B2264/00; B32B2264/10; B32B2264/104; B32B2307/00; B32B2307/30; B32B2307/31; B32B2307/70; B32B2307/724; B32B2307/732; B32B2323/00; B32B2323/04; B32B2323/046; B32B2323/10; B32B2439/00; B32B2439/70; B32B2555/00; B32B2555/02; C08J2323/00; C08J2323/02; C08J2423/00; C08J2427/00; Y; Y10; Y10S; Y10S428/00; Y10S428/91; Y10T; Y10T428/00; Y10T428/249921; Y10T428/249953; Y10T428/249982; Y10T428/249983; Y10T428/249985; Y10T428/249986; Y10T428/31504; Y10T428/31855; Y10T428/31909; Y10T428/31913
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
42 words
A gas permeable microporous film comprising a voided polyolefin matrix having, on at least one of its surfaces, a coating of a heat sealable polymer having a melting point at least 10° C. lower than that of the voided polyolefin matrix polymer.
Claim 2
Dependent Claim
42 words
A gas permeable microporous film comprising a voided polyolefin matrix having, on at least one of its surfaces, a coating of a heat sealable polymer having a melting point at least 10° C. lower than that of the voided polyolefin matrix polymer.
Claim 3
Dependent Claim
11 words
The film of claim 1 wherein the matrix polymer is homopolypropylene.
Claim 4
Dependent Claim
19 words
The film of claim 1 wherein the matrix polymer is a blend of a homopolypropylene and a propylene--ethylene copolymer.
Claim 5
Dependent Claim
25 words
The film of claim 3 wherein the matrix polymer contains about 30 to 70% calcium carbonate, based on total weight of matrix polymer plus filler.
Claim 6
Dependent Claim
36 words
The film of claim 3 wherein the thickness ratio of the matrix film to heat sealable coating is about 3 to 1 to about 20 to 1, preferably about 5 to 1 to 20 to 1.
Claim 7
Dependent Claim
36 words
The film of claim 4 wherein the thickness ratio of the matrix film to heat sealable coating is about 3 to 1 to about 20 to 1, preferably about 5 to 1 to 20 to 1.
Claim 8
Dependent Claim
30 words
The film of claim 3 wherein the heat sealable coating is a medium or low density polyethylene or copolymer of ethylene with an alpha-olefin having 3 to 8 carbon atoms.
Claim 9
Dependent Claim
30 words
The film of claim 4 wherein the heat sealable coating is a medium or low density polyethylene or copolymer of ethylene with an alpha-olefin having 3 to 8 carbon atoms.
References Cited (Backward Citations)
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Cited
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US3908650A
Cited
US4596738A
Cited
US4582752A
Cited
US4626460A
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) | 1991-03-29 | 1991-09-28 | 1992-03-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-03-29 | 1995-09-28 | 1996-03-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-03-29 | 1999-09-28 | 2000-03-29 | $7700.00 | Window Closed / Lapsed |