US4612221A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Multilayer food wrap with cling
Assignee: Glad Products Co
•
Filing: 1985-12-20
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Granted: 1986-09-16
•
Expires: 2005-12-20
Abstract
Abstract A multilayer film food wrap having outer layers of a polyolefin resin including a cling agent, and a core layer of a resin having a high melting point, resistance to heat, low permeability to oxygen, moisture and odor, and film toughness. Methods of preparing the film and fabricating the film into a bag are also disclosed.
Inventors
- 👤 Edward N. Biel
- 👤 George F. Kirkpatrick
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 04:32
CPC Classifications
B; B32; B32B; B32B27/00; B32B27/06; B32B27/08; B32B27/18; B32B27/32; B32B2307/00; B32B2307/30; B32B2307/306; B32B2307/70; B32B2307/724; B32B2307/7242; B32B2307/7244; B32B2307/7246; B32B2307/7248; B32B2439/00; B32B2439/70; Y; Y10; Y10T; Y10T428/00; Y10T428/13; Y10T428/1334; Y10T428/1341; Y10T428/31504; Y10T428/31725; Y10T428/31739; Y10T428/31743; Y10T428/31746; Y10T428/31786; Y10T428/31797; Y10T428/31855; Y10T428/31909; Y10T428/31913; Y10T428/31928
Claims Analysis
Total Claims: 36
Claim 1
Independent Claim
105 words
A multilayer film suitable for use in microwave oven cooking consisting essentially of outer layers of a polyolefin resin including a cling agent, each of said outer layers having a thickness of from about 0.1 mil to about 1.0 mil, said polyolefin resin being selected from the group consisting of polyethylene, polypropylene, and polybutylene, and a core layer of a thermoplastic resin having a melting point of at least about 335° F., resistance to heat, low permeability to oxygen, moisture and odor, and film toughness, said thermoplastic resin being selected from the group consisting of polyamides, polybutylene terephthalate, polyethylene terephthalate, ethylene-vinyl alcohol, and mixtures thereof.
Claim 2
Dependent Claim
105 words
A multilayer film suitable for use in microwave oven cooking consisting essentially of outer layers of a polyolefin resin including a cling agent, each of said outer layers having a thickness of from about 0.1 mil to about 1.0 mil, said polyolefin resin being selected from the group consisting of polyethylene, polypropylene, and polybutylene, and a core layer of a thermoplastic resin having a melting point of at least about 335° F., resistance to heat, low permeability to oxygen, moisture and odor, and film toughness, said thermoplastic resin being selected from the group consisting of polyamides, polybutylene terephthalate, polyethylene terephthalate, ethylene-vinyl alcohol, and mixtures thereof.
Claim 3
Dependent Claim
49 words
A multilayer film in accordance with claim 1 wherein said cling agent is selected from the group consisting of glycerol monooleate, sorbitan monooleate, sorbitan trioleate, glycerol dioleate, mono- and diglycerides, vegetable oils, fatty esters, polybutene polymers, polyisobutylene polymers, ethoxylated nonylphenols, mineral oil, saturated aliphatic and alicyclic hydrocarbons, and surfactants.
Claim 4
Dependent Claim
41 words
A multilayer film in accordance with claim 1 wherein said cling agent is present in each of said outer layers at a concentration of from about 0.5 to about 2.0 percent by weight, based on the weight of said outer layers.
Claim 5
Dependent Claim
17 words
A multilayer film in accordance with claim 1 wherein said polyamides include Nylon, Nylon-6, Nylon-6.6, and Nylon-12.
Claim 6
Dependent Claim
24 words
A multilayer film in accordance with claim 1 wherein said outer layers of polyolefin resin comprise polypropylene and said core layer comprises a polyamide.
Claim 7
Dependent Claim
20 words
A multilayer film in accordance with claim 1 including a bonding layer between said core layer and said outer layers.
Claim 8
Dependent Claim
33 words
A multilayer film in accordance with claim 6 wherein said bonding layer provides a bonding strength between said core layer and said outer layers of at least about 200 grams/inch of said film.
Claim 9
Dependent Claim
40 words
A multilayer film in accordance with claim 6 wherein said bonding layer comprises an adhesive resin selected from the group consisting of ionomer copolymers, modified polyolefins, ethylene-vinyl acetate copolymers, ethylene-acrylic acid copolymers, polyolefins grafted with acrylic acid, and mixtures thereof.
Claim 10
Dependent Claim
35 words
A multilayer film in accordance with claim 1 wherein said outer layers of polyolefin resin comprise a polypropylene random copolymer having a melt flow index of between about 2 and about 25 decigrams per minute.
Claim 11
Dependent Claim
24 words
A multilayer film in accordance with claim 1 wherein the total thickness of said film is from about 0.3 mil to about 3 mils.
Claim 12
Dependent Claim
24 words
A multilayer film in accordance with claim 1 wherein the thickness of said core layer is from about 0.05 mil to about 1.0 mil.
Claim 13
Dependent Claim
24 words
A multilayer film in accordance with claim 6 wherein the thickness of said bonding layer is from about 0.03 mil to about 0.60 mil.
Claim 14
Dependent Claim
29 words
A multilayer film in accordance with claim 1 wherein said film has an outer layer to core layer to outer layer thickness ratio of from 1:1:1 to about 4:1:4.
Claim 15
Dependent Claim
10 words
A bag fabricated from the multilayer film of claim 1.
Claim 16
Independent Claim
110 words
A method of preparing a multilayer film suitable for use in microwave oven cooking comprising slot cast extruding outer layers of a polyolefin resin including a cling agent, each of said outer layers having a thickness of from about 0.1 mil to about 1.0 mil, said polyolefin resin being selected from the group consisting of polyethylene, polypropylene, and polybutylene, and a core layer of a thermoplastic resin having a melting point of at least about 335° F., resistance to heat, low permeability to oxygen, moisture and odor, and film toughness, said thermoplastic resin being selected from the group consisting of polyamides, polybutylene terephthalate, polyethylene terephthalate, ethylene-vinyl alcohol, and mixtures thereof.
Claim 17
Independent Claim
110 words
A method of preparing a multilayer film suitable for use in microwave oven cooking comprising slot cast extruding outer layers of a polyolefin resin including a cling agent, each of said outer layers having a thickness of from about 0.1 mil to about 1.0 mil, said polyolefin resin being selected from the group consisting of polyethylene, polypropylene, and polybutylene, and a core layer of a thermoplastic resin having a melting point of at least about 335° F., resistance to heat, low permeability to oxygen, moisture and odor, and film toughness, said thermoplastic resin being selected from the group consisting of polyamides, polybutylene terephthalate, polyethylene terephthalate, ethylene-vinyl alcohol, and mixtures thereof.
Claim 18
Dependent Claim
48 words
A method in accordance with claim 15 wherein said cling agent is selected from the group consisting of glycerol monooleate, sorbitan monooleate, sorbitan trioleate, glycerol dioleate, mono- and diglycerides, vegetable oils, fatty esters, polybutene polymers, polyisobulytene polymers, ethoxylated nonylphenols, mineral oil, saturated aliphatic and alicyclic hydrocarbons, and surfactants.
Claim 19
Dependent Claim
40 words
A method in accordance with claim 15 wherein said cling agent is present in each of said outer layers at a concentration of from about 0.5 to about 2.0 percent by weight, based on the weight of said outer layers.
Claim 20
Dependent Claim
16 words
A method in accordance with claim 15 wherein said polyamides include Nylon, Nylon-6, Nylon-6.6, and Nylon-12.
Claim 21
Dependent Claim
23 words
A method in accordance with claim 15 wherein said outer layers of polyolefin resin comprise polypropylene and said core layer comprises a polyamide.
Claim 22
Dependent Claim
20 words
A method in accordance with claim 15 including applying a bonding layer between said core layer and said outer layers.
Claim 23
Dependent Claim
32 words
A method in accordance with claim 20 wherein said bonding layer provides a bonding strength between said core layer and said outer layers of at least about 200 grams/inch of said film.
Claim 24
Dependent Claim
39 words
A method in accordance with claim 20 wherein said bonding layer comprises an adhesive resin selected from the group consisting of ionomer copolymers, modified polyolefins, ethylene-vinyl acetate copolymers, ethylene-acrylic acid copolymers, polyolefins grafted with acrylic acid, and mixtures thereof.
Claim 25
Dependent Claim
34 words
A method in accordance with claim 15 wherein said outer layers of polyolefin resin comprise a polypropylene random copolymer having a melt flow index of between about 2 and about 25 decigrams per minute.
Claim 26
Dependent Claim
23 words
A method in accordance with claim 15 wherein the total thickness of said film is from about 0.3 mil to about 3 mils.
Claim 27
Dependent Claim
23 words
A method in accordance with claim 15 wherein the thickness of said core layer is from about 0.05 mil to about 1.0 mil.
Claim 28
Dependent Claim
23 words
A method in accordance with claim 20 wherein the thickness of said bonding layer is from about 0.03 mil to about 0.60 mil.
Claim 29
Dependent Claim
29 words
A method in accordance with claim 15 wherein said film has an outer layer to core layer to outer layer thickness ratio of from about 1:1:1 to about 4:1:4.
Claim 30
Dependent Claim
15 words
A method in accordance with claim 15 including fabricating a bag from said multilayer film.
Claim 31
Dependent Claim
71 words
A multilayer film suitable for use in microwave oven cooking comprising two outer layers of polypropylene containing a cling agent, and a core layer of a thermoplastic resin having a melting point of at least about 335° F., resistance to heat, low permeability to oxygen, moisture and odor, and film toughness, said thermoplastic resin being selected from the group consisting of polyamides, polybutylene terephthalate, polyethylene terephthalate, ethylene-vinyl alcohol, and mixtures thereof.
Claim 32
Dependent Claim
71 words
A multilayer film suitable for use in microwave oven cooking comprising two outer layers of polypropylene containing a cling agent, and a core layer of a thermoplastic resin having a melting point of at least about 335° F., resistance to heat, low permeability to oxygen, moisture and odor, and film toughness, said thermoplastic resin being selected from the group consisting of polyamides, polybutylene terephthalate, polyethylene terephthalate, ethylene-vinyl alcohol, and mixtures thereof.
Claim 33
Dependent Claim
31 words
A multilayer film in accordance with claim 29 wherein said polypropylene comprises a polypropylene random copolymer having a melt flow index of between about 2 and about 25 decigrams per minute.
Claim 34
Independent Claim
78 words
A method of preparing a multilayer film suitable for use in microwave oven cooking comprising slot cast extruding two outer layers of polypropylene containing a cling agent, and a core layer of a thermoplastic resin having a melting point of at least about 335° F., resistance to heat, low permeability to oxygen, moisture and odor, and film toughness, said thermoplastic resin being selected from the group consisting of polyamides, polybutylene terephthalate, polyethylene terephthalate, ethylene-vinyl alcohol, and mixtures thereof.
Claim 35
Independent Claim
78 words
A method of preparing a multilayer film suitable for use in microwave oven cooking comprising slot cast extruding two outer layers of polypropylene containing a cling agent, and a core layer of a thermoplastic resin having a melting point of at least about 335° F., resistance to heat, low permeability to oxygen, moisture and odor, and film toughness, said thermoplastic resin being selected from the group consisting of polyamides, polybutylene terephthalate, polyethylene terephthalate, ethylene-vinyl alcohol, and mixtures thereof.
Claim 36
Dependent Claim
35 words
A method of preparing a multilayer film in accordance with claim 31 wherein said polypropylene comprises a polypropylene random copolymer having a melt flow index of between about 2 and about 25 decigrams per minute.
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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) | 1989-09-15 | 1990-03-17 | 1990-09-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-09-15 | 1994-03-17 | 1994-09-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-09-15 | 1998-03-17 | 1998-09-16 | $7700.00 | Window Closed / Lapsed |