# US 5,345,069 A · Microwavable frozen impact-resistant hermetically sealed food package > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,345,069 A - Document ID: US5345069A - Status: Granted - Kind: A - Application number: 07/761,153 - Filed: 1991-09-17 - Granted: 1994-09-06 - Earliest claimed: 1991-09-17 - Assignees: Oscar Mayer Foods Corporation - Inventors: Paul E. Grindrod - Web page: https://patentgrep.com/patent/US5345069A ## CPC - B65D 77/2032: {by peeling or tearing the cover from the container} - B65D 81/3446: {specially adapted to be heated by microwaves} - B65D 2577/2025: Multi-layered container, e.g. laminated, coated - Y10S 99/14: Induction heating - Y10T 428/31507: Of polycarbonate - B65D: CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES - Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS - Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION ## Abstract A gas-flushed microwavable easy-to-open food package is provided which is resistant to impact under temperatures at or below freezing and which is comprised of a flexible lidding film having oxygen-barrier properties hermetically and peelably sealed to a food compartment formed from a polypropylene copolymer material. The lidding film is preferably comprised of oriented polyester, and the food product compartment further comprises a peelable oxygen, barrier film, preferably formed of ethylene vinyl acetate, PVDC and a peelable polyethylene layer. The package is designed to contain a perishable food product, such as a wiener in a bun or other proteinaceous-farinaceous food combinations, and is preferably entirely or partially transparent so as to allow the consumer to readily observe the condition of the food product before purchase. The package is particularly advantageous in that it provides impact protection and maintains freshness for a food product that is shipped frozen and kept at refrigeration temperatures near point of sale, and can also be microwaved to serving temperatures without thermal distortion. ## Claims ### Claim 1 A freezable and microwavable easy-to-open food package capable of containing a rapidly perishable food product that is visually assessable to the consumer prior to opening said package comprising: a food product compartment capable of withstanding impact at low temperatures and capable of resisting deformation when microwaved, and which includes a peelable oxygen barrier film having an oxygen permeability of no greater than about 1 cc of oxygen per 100 square inches per atmosphere at room temperature, and a flexible lidding film hermetically and peelably sealed to said food product compartment, said lidding film capable of withstanding normal impact at low temperatures, capable of substantially preventing the transmission of oxygen and moisture, and capable of being heated while sealed to said food product compartment in a microwave oven without deformation. ### Claim 2 (depends on 1) A package according to claim 1 wherein said lidding film is comprised of a material selected from the group consisting of polyester and nylon. ### Claim 3 (depends on 1) A package according to claim 1 wherein said lidding film is comprised of oriented polyester. ### Claim 4 (depends on 3) A package according to claim 3 wherein said lidding film further comprises a coating layer which provides oxygen barrier properties. ### Claim 5 (depends on 4) A package according to claim 4 wherein said coating layer of said lidding film is comprised of a material selected from the group consisting of polyvinylidene dichloride, ethylene vinyl alcohol, ethylene vinyl alcohol copolymers, ultra-thin glass and acrylonitrile-methyl methacrylate copolymers. ### Claim 6 (depends on 4) A package according to claim 4 wherein said lidding film further comprises a layer of polyethylene. ### Claim 7 (depends on 1) A package according to claim 1 wherein said lidding film is comprised of polyethylene terephthalate. ### Claim 8 (depends on 1) A package according to claim 1 wherein said lidding film includes an anti-fogging agent. ### Claim 9 (depends on 6) A package according to claim 6 wherein said layer of polyethylene includes an anti-fogging agent. ### Claim 10 (depends on 1) A package according to claim 1 wherein said lidding film is heat sealed to said food product compartment. ### Claim 11 (depends on 6) A package according to claim 6 wherein said lidding film is heat sealed to said food product compartment with the polyethylene layer contacting the food product compartment. ### Claim 12 (depends on 1) A package according to claim 1 wherein the food product compartment is formed into a tray having a peripheral flange which provides a surface for attachment of said lidding film to said compartment. ### Claim 13 (depends on 1) A package according to claim 1 wherein said food compartment is transparent. ### Claim 14 (depends on 1) A package according to claim 1 wherein said lidding film is transparent. ### Claim 15 (depends on 1) A package according to claim 1 wherein said food product compartment is comprised of a polypropylene copolymer. ### Claim 16 (depends on 1) A package according to claim 1 wherein said food product compartment is comprised of polyethylene and polypropylene. ### Claim 17 (depends on 1) A package according to claim 1 wherein said food product compartment is comprised of a material selected from the group consisting of polycarbonates, cellulose acetate-butyrate and ethocell. ### Claim 18 (depends on 1) A package according to claim 1 wherein said peelable oxygen barrier film is comprised of a laminable surface layer, an oxygen barrier layer and a peelably sealable surface layer. ### Claim 19 (depends on 18) A package according to claim 18 wherein said laminable surface layer comprises ethylene vinyl acetate or a polyolefinic copolymer, wherein said oxygen barrier comprises a material selected from the group consisting of polyvinylidene dichloride, ethylene vinyl alcohol, ethylene vinyl alcohol copolymers, ultra-thin glass and acrylonitrile-methyl methacrylate copolymers, and wherein said peelably sealable surface layer is selected from the group consisting of polyethylene, modified polyethylene, peelable polyolefins and polybutenes. ### Claim 20 (depends on 1) A package according to claim 1 wherein said food product compartment is shaped so as to enclose a wiener in a bun. ### Claim 21 (depends on 1) A package according to claim 1 wherein said food product compartment is gas-flushed before said lidding film is sealed thereto. ### Claim 22 (depends on 1) A package according to claim 1 wherein said food product compartment is preformed using a multiple unit thermoformer. ### Claim 23 An easy-to-open food package for a combination proteinaceous and farinaceous food product capable of maintaining the freshness of the food product at low temperatures while also being capable of withstanding microwave heating sufficient to heat the food product without thermal distortion and capable of having said food product visually assessed by the consumer while in said package, comprising: a food product compartment shaped to accommodate the food product having an upper opening, said compartment capable of withstanding impact at low temperatures so as to protect the food product and capable of withstanding microwaving without thermal degradation, and including a peelable oxygen barrier film having an oxygen permeability of no greater than about 1 cc of oxygen per 100 square inches per atmosphere at room temperature, and a flexible lidding film hermetically and peelably sealed to the upper opening of said food product compartment, said lidding film capable of withstanding microwaving while remaining sealed to said food product compartment without thermal degradation, capable of withstanding impact at low temperatures, and comprising an oxygen and moisture barrier to prevent degradation of the proteinaceous and farinaceous food product at low temperatures. ### Claim 24 (depends on 23) A package according to claim 23 wherein said food product compartment is comprised of a polypropylene copolymer. ### Claim 25 (depends on 23) A package according to claim 23 wherein said lidding film is comprised of a material selected from the group consisting of polyester and nylon. ### Claim 26 (depends on 23) A package according to claim 23 wherein the food product compartment is formed into a tray having a peripheral flange which provides a surface for attachment of said lidding film to said compartment. ### Claim 27 (depends on 23) A package according to claim 23 wherein said food product compartment is shaped so as to enclose a wiener in a bun. ### Claim 28 (depends on 25) A package according to claim 25 wherein said lidding film further comprises a coating layer which provides oxygen barrier properties. ### Claim 29 (depends on 23) A package according to claim 23 wherein said food compartment is transparent. ### Claim 30 (depends on 23) A package according to claim 23 wherein said lidding film is transparent.