US4771935A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Plastic containers embodying a peel seal and method of preparing same
Assignee: PLASTIC PACKAGING PRODUCTS Co A CORP OF DELAWARE
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Filing: 1987-06-03
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Granted: 1988-09-20
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Expires: 2007-06-03
Abstract
Abstract A polyolefin container is disclosed which is hermetically sealed with a complementary lid extending across the open container the opposed faces of the container surface and the lid being bonded together by a peelable, heat seal layer intermediate between the opposed faces. The heat seal layer is comprised of a mixture of a particulate filler and first and second polyolefin resins, the second polyolefin resin having a melt flow rate at least about three times greater than the melt flow rate of the first polyolefin resin.
Inventors
- 👤 Ihab M. Hekal
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 11:29
CPC Classifications
B; B32; B32B; B32B27/00; B32B27/32; B32B15/00; B32B15/04; B32B15/08; B32B15/20; B32B27/18; B32B27/20; B65; B65D; B65D77/00; B65D77/10; B65D77/20; B65D77/2024; B65D2577/00; B65D2577/10; B65D2577/20; B65D2577/2025; B65D2577/2041; B65D2577/205
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
146 words
A package comprised of a container formed from a structure having a sealing surface formed from a polypropylene resin, the container having a complementary lid, the lid having a contact face and extending across an opening in the container in contact with the sealing surface, the contact face of the lid and sealing surface being opposed and bonded together by an internally cleavable heat seal layer intermediate between the opposed lid contact and sealing surface, the heat seal layer being comprised of a mixture of about 40 to about 55 percent by weight of a first polypropylene resin having a melt flow rate of about 2 to about 8, about 10 to about 25 percent by weight of a second polypropylene resin having a melt flow rate of about 20 to about 60 and about 25 to about 40 percent by weight of a particulate filler.
Claim 2
Dependent Claim
146 words
A package comprised of a container formed from a structure having a sealing surface formed from a polypropylene resin, the container having a complementary lid, the lid having a contact face and extending across an opening in the container in contact with the sealing surface, the contact face of the lid and sealing surface being opposed and bonded together by an internally cleavable heat seal layer intermediate between the opposed lid contact and sealing surface, the heat seal layer being comprised of a mixture of about 40 to about 55 percent by weight of a first polypropylene resin having a melt flow rate of about 2 to about 8, about 10 to about 25 percent by weight of a second polypropylene resin having a melt flow rate of about 20 to about 60 and about 25 to about 40 percent by weight of a particulate filler.
Claim 3
Dependent Claim
11 words
The package of claim 1 herein the particulate filler is talc.
Claim 4
Dependent Claim
16 words
The package of claim 1 wherein the first and second polypropylene resins are a polypropylene-ethylene-butadiene copolymer.
Claim 5
Dependent Claim
27 words
The package of claim 1 wherein the melt flow rate of the second polypropylene resin is 6 times the melt flow rate of the first polypropylene resin.
Claim 6
Dependent Claim
15 words
The package of claim 1 wherein the container is formed from a laminated film structure.
Claim 7
Dependent Claim
24 words
The package of claim 5 wherein the laminated film structure is provided with an inner gas barrier layer interposed between the outer polypropylene layers.
Claim 8
Dependent Claim
18 words
The package of claim 6 wherein the inner gas barrier layer is formed from a vinylidene chloride polymer.
Claim 9
Dependent Claim
32 words
The package of claim 1 wherein the lid is comprised of bonded layers from exterior to interior of a foil of aluminum and a layer of a heat activatable carboxyl modified polypropylene.
Claim 10
Dependent Claim
17 words
The package of claim 1 wherein the heat seal layer is an integral part of the container.
Claim 11
Independent Claim
179 words
A method of making a package comprised of a container part heat sealed with a lid having a contact face the container part having a contact face formed from a polypropylene resin, the contact face of the lid and container part being placed in opposed relation to be hermetically heat sealed together, which method comprises applying to at least one of the opposed faces a heat sealable layer in which the cohesive strength of the heat seal layer is less than the tensile strength of the heat seal layer so that the layer cleaves within itself when forces are applied to the parts to pull them apart, the heat seal layer being comprised of a mixture of about 40 to about 55 percent by weight of a first polypropylene resin having a melt flow rate of about 2 to about 8, about 10 to about 25 percent by weight of a second polypropylene resin having a melt flow rate of at about 20 to about 60 and about 25 to about 40 percent by weight of a particulate filler.
Claim 12
Independent Claim
179 words
A method of making a package comprised of a container part heat sealed with a lid having a contact face the container part having a contact face formed from a polypropylene resin, the contact face of the lid and container part being placed in opposed relation to be hermetically heat sealed together, which method comprises applying to at least one of the opposed faces a heat sealable layer in which the cohesive strength of the heat seal layer is less than the tensile strength of the heat seal layer so that the layer cleaves within itself when forces are applied to the parts to pull them apart, the heat seal layer being comprised of a mixture of about 40 to about 55 percent by weight of a first polypropylene resin having a melt flow rate of about 2 to about 8, about 10 to about 25 percent by weight of a second polypropylene resin having a melt flow rate of at about 20 to about 60 and about 25 to about 40 percent by weight of a particulate filler.
Claim 13
Dependent Claim
11 words
The method of claim 10 wherein the particulate filler in talc.
Claim 14
Dependent Claim
16 words
The method of claim 10 wherein the first and second polypropylene resins are a polypropylene-ethylene-butadiene copolymer.
Claim 15
Dependent Claim
27 words
The method of claim 10 wherein the melt flow rate of the second polypropylene resin is 6 times the melt flow rate of the first polypropylene resin.
Claim 16
Dependent Claim
17 words
The method of claim 10 wherein the polypropylene container part is formed from a laminated film structure.
Claim 17
Dependent Claim
22 words
The method of claim 14 wherein the laminated film structure has an inner gas barrier layer interposed between the outer polypropylene layers.
Claim 18
Dependent Claim
18 words
The method of claim 15 wherein the inner gas barrier layer is formed from a vinylidene chloride polymer.
Claim 19
Dependent Claim
31 words
The method of claim 10 wherein the lid is comprised of bonded layers from exterior to interior of a foil aluminum and a layer of a heat activatable carboxyl modified polypropylene.
Claim 20
Dependent Claim
17 words
The method of claim 10 wherein the heat seal layer is an integral part of the container.
Claim 21
Dependent Claim
27 words
The method of claim 10 wherein the heat source for heat sealing is applied to surface opposite the surface to which the heat seal layer is applied.
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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) | 1991-09-20 | 1992-03-21 | 1992-09-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-09-20 | 1996-03-21 | 1996-09-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-09-20 | 2000-03-21 | 2000-09-20 | $7700.00 | Window Closed / Lapsed |