WO1996009967A1

WO1996009967A1 - Microwave food heating package including overwrap and method

Info

Publication number: WO1996009967A1
Application number: PCT/US1995/012958
Authority: WO
Inventors: Lance B. Schilmoeller; Charles H. Turpin; Paul J. Warosh; Kevin S. Mcfadden; Jeffrey T. Watkins; James W. Montealegre
Original assignee: Golden Valley Microwave Foods, Inc.
Priority date: 1994-09-29
Filing date: 1995-09-28
Publication date: 1996-04-04
Also published as: AU3860095A

Abstract

A microwave food heating package (10) includes an inner construction including a susceptor (11) which heats in the presence of microwave energy, and a carton (400) positioned around and secured with the susceptor. The carton defines a rectangular shape with an open end. A paper overwrap (404) encloses the inner construction. An outer polymeric film overwrap may be bonded to the paper overwrap (406). The overwrap has at least two parallel seals (92), a tear apparatus (106) and a tear notch (307a). At least one vent opening may be provided in the overwrap (138). The overwrap is constructed so that cooking of the food items contained within the package can occur without removal or alteration of the overwrap. Upon cooking of the food items, the overwrap serves as a food dispensing apparatus after removal of the susceptor and the carton. A seasoning packet (124) can be attached to the carton for removal with the carton during use.

Description

MICROWAVE FOOD HEATING PACKAGE INCLUDING OVERWRAP AND METHOD

FIELD OF INVENTION The present invention relates to a microwave heating package with an overwrap for use with food items which are heated in a microwave oven.

BACKGROUND OF THE INVENTION Various microwave food heating packages are known which are used to contain food items during storage and handling, and during heating of food items in a microwave oven. U.S. Patent No. 4,943,439 concerns microwave receptive heating sheets and packages containing them. The microwave receptive heating sheets, or "susceptors", absorb a portion of the microwave energy and transfer it by conduction to a food item. The susceptors facilitate crisping, toasting or browning of surfaces of the food items, such as french-fried potatoes, heatable in a microwave oven.

Various concerns arise in connection with the manufacture and use of microwave food heating packages. One area of concern is with respect to the cost of the packaging components and the efficiency that they are assembled with the food items. Another area of concern is with respect to ease of use during cooking of the food items in a microwave oven, and subsequent dispensing of the food items once cooked. Minimal manipulations by the consumer are highly desired. Easy access to the food items without excessive risk of burning the consumer is preferred. Also, achieving properly cooked food items is a concern. One particular situation of possible concern is automated merchandising of food products such as with a vending machine which includes a microwave oven contained within the machine. In that situation, it is desired to reduce the manipulations of the package necessary by the consumer during use, while achieving properly cooked food items. There is a need in the art for improved microwave food heating packages that address at least some of the above concerns, and other concerns related to manufacture and use of the packages.

SUMMARY OF THE INVENTION

The present invention includes an overwrap for use in a microwave food heating package, and a method of using a microwave food heating package including an overwrap. The microwave food heating package includes an inner construction preferably including a susceptor which heats in the presence of microwave energy, and a carton, preferably paperboard, positioned around the susceptor.

In some embodiments, the inner construction may only include a susceptor or a carton. The preferred embodiment includes both a carton and a susceptor secured together for handling as a single unit after cooking.

An overwrap encloses the inner construction. The overwrap is suitably constructed to remain around the inner construction during exposure to microwave energy.

Following cooking of the food item or items, an opening is formed in the overwrap permitting removal of the susceptor and the carton of the inner construction, thereby leaving behind the food item or items within the overwrap. Preferably, the overwrap is constructed from a paper material, and/or other material which will not melt or otherwise deteriorate during heating of the food items, and also will allow for proper venting. Preferably, the overwrap is constructed from a material that will sufficiently not retain heat to prevent discomfort or burning to the consumer upon handling following cooking. Further, it is preferred that the overwrap material allow for tearing or opening to permit easy access to the food items and/or the inner construction. The overwrap preferably includes at least two opposed seals positioned perpendicular to an open end of the carton. During use, an end panel of the overwrap is preferably torn from one opposed seal toward the other, thereby forming an opening in the overwrap to permit removal of the susceptor and the carton. Preferably, at least one tear apparatus, such as a tear strip and/or a perforation line, is provided with the overwrap to facilitate forming the opening therein by the consumer. A tear notch in one seal is also preferably provided to assist in guiding the consumer for a proper tear. During use, the food items can be cooked without removing the overwrap or altering the overwrap in construction by the consumer. Once the food items are cooked, the susceptor and the carton can be removed from the overwrap, leaving the food items conveniently contained within the overwrap for dispensing to the consumer, as desired. Preferably, a vent opening is provided in one or more of the seals for the passage of heated air and/or steam during cooking. This assists in forming a pouch-like package, which after opening, allows for easy removal of the carton and/or susceptor, and the food to be dispensed therefrom.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a front view of one embodiment of a microwave food heating package in accordance with the invention.

Fig. 2 is a top view of the package of Fig. 1.

Fig. 3 is a cross-sectional view of the package of Fig. 1, taken along lines 3-3.

Fig. 4 is an enlarged cross-sectional view of a portion of the susceptor contained within the package of Fig. 1.

Fig. 5 shows the package of Fig. 1 utilized in a microwave oven.

Figs. 6 - 9 show a sequence of steps for using the package of Fig. 1 following cooking in a microwave oven.

Fig. 10 shows the inside surface of the overwrap before being positioned around the carton. Fig. 11 is an enlarged view of a portion of the overwrap showing one of the tear strips in greater detail. Fig. 12 shows the carton in a flattened state before being positioned to define a rectangle. Fig. 13 is an enlarged view of a portion of the carton and the susceptor, with the food items removed, showing a retention feature for retaining the susceptor within the carton.

Fig. 14 is an enlarged view of a portion of an alternative overwrap showing another tear apparatus to the one shown in Fig. 11.

Fig. 15 is a front view of an alternative embodiment of a microwave food heating package in accordance with the invention. Fig. 16 shows the inside surface of the overwrap of the package of Fig. 15 before the overwrap is positioned around the carton.

Fig. 17 is an enlarged view of a portion of the overwrap of Fig. 16 showing one of the tear strips and line of perforations in greater detail.

Fig. 18 shows a laminate overwrap of paper and a polymeric film layer of a further alternative embodiment of a microwave food heating package where the polymeric film layer only covers a selected portion of the paper.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention concerns a package for use in microwave heating of foods. The package generally comprises an inner construction for holding a food product for heating, and an overwrap enclosing the inner construction at least partially. The overwrap is configured to provide an opening where the inner construction can be removed, leaving the cooked food in the overwrap which functions as a serving utensil or dish for the consumer. The overwrap can be placed in the microwave oven with the food and the inner construction.

Following heating in the microwave, and consumption of the food, the package components are disposable. Therefore, inexpensive materials and configurations for the package are preferred, such as paper or paperboard. Such constructions may be recyclable, if desired. A wide variety of foods may be heated in the package including elongated food items and other shapes. The package was developed and designed specifically to provide for convenient packaging, handling, heating and consumption of elongated food pieces, such as a single serving of french fries, which are heated utilizing a microwave oven. Generally, it is anticipated that the package of the present invention will be stored with the food frozen. The package of the present invention is configured for use in an automated merchandising system, such as a vending machine, where the microwave cooking process is automated.

Figs. 1 - 13 illustrate one preferred construction and use of a microwave food heating package 10 including an overwrap in accordance with the invention. Fig. 14 illustrates one alternative embodiment for package 10. Figs. 15 - 17 illustrate an alternative preferred embodiment of a microwave food heating package 200 including an overwrap in accordance with the invention. The overwrap of package 10 includes a paper construction. The overwrap of package 200 includes a laminate construction of an inner paper layer and an outer polymeric film layer, such as polyester. Fig. 18 illustrates a further alternative preferred embodiment of a food heating package 400 to the embodiment of Figs. 15- 17. Package 400 includes a laminate construction of an inner paper layer and an outer polymeric film layer, such as polyester, where the polymeric film layer is only covering a selected portion of the paper. The constructions of the overwraps of the preferred embodiments of the invention will be discussed in greater below.

Referring now to Figs. 1 - 3, microwave food heating package 10 includes an inner construction 11 preferably including a susceptor 12, and a carton 14, or shell, surrounding susceptor 12. An outer protective overwrap 16 encloses inner construction 11 as shown in Figs. 1 and 3. Preferably overwrap 16 is flexible and foldable during assembly and use. Susceptor 12 heats in the presence of microwave energy to cook, crisp, brown, or toast a food item positioned adjacent to susceptor 12. In the preferred embodiment shown, susceptor 12 defines a plurality of food chambers 18 each receiving a food item 66. Food item 66 is in the nature of an elongated food portion, such as a french fry, fish stick or other food to be heated/prepared in the microwave oven. Food chambers 18 and food items 66 extend in a parallel direction represented by arrow 22 in Fig. 1. Both overwrap 16 and carton 14 are transparent to microwave energy.

U.S. Patent No. 4,943,439 shows several examples of susceptor 12 and carton 14 constructions. The disclosure of U.S. Patent No. 4,943,439 is incorporated herein by reference. U.S. Patent Nos. 5,034,234; 5,096,723; and 5,334,820 concerns further constructions with respect to susceptor 12 and carton 14. The disclosures of U.S. Patent Nos. 5,034,234; 5,096,723; and 5,334,820 are incorporated herein by reference.

Referring now to Fig. 4, an example construction of susceptor 12 is shown. Susceptor 12 has a sheet configuration (flat, fluted, or other shape) with a plurality of layers laminated together, including an inner sheet of paper 34 adhesively attached to a plastic layer 38 with an adhesive layer 36. Plastic layer 38 includes a microwave active coating or layer 40 mounted to plastic 38, such as aluminum deposited by vacuum metallization or vapor deposition. An outer paper layer 44 is wet or dry bond laminated with an adhesive 42 to metal layer 40. The metal coating is sufficiently conductive so that it will interact with the microwave energy and a microwave oven to absorb a portion of the microwave energy, converting it to heat. Other known coatings or substances that will become hot in a microwave oven can be used in place of the metal coating if desired. Outer paper layer 44 is optional, and so is plastic layer 38.

As shown in Fig. 3, susceptor 12 includes three separate trays or sheets 50, 52 and 54 constructed with spaced-apart dividers or flutes 60, 62 and 64 to define a plurality of three-sided food receivers or chambers 18 for receipt of food item 66. Preferably, microwave active or susceptor material is positioned in each of sheets 50, 52 and 54 including dividers 60, 62 and 64. Sheets 50, 52 and 54 are stacked one on top of the other to form susceptor 12 but are otherwise not secured to one another in the preferred embodiment. Other configurations for susceptor 12 are possible including planar sheets, or zig- zag or accordion shape, for example, and more or less numbers of sheets can be used. The configuration of susceptor 12 is selected based upon the desired heating effect and the shape of the food items to be cooked.

For sheets 50, 52 and 54, materials and configurations such as those utilized for french fry trays in U.S. Patent Nos. 4,943,439; 5,034,234; 5,096,723; and 5,334,820 previously incorporated herein by reference will be preferred. Commercially useable susceptor sheet materials are available from Phoenix Packaging of Maple Grove, Minnesota. The preferred sheets comprise a fluted 35 lb. bleached Kraft sheet coated on one side with Quillon (a food grade release agent available from du Pont of Wilmington, Delaware) wet or dry bond laminated to a metallized film. A suitable Kraft sheet is available from Rhinelander Paper Company of Rhinelander, Wisconsin. A preferred metallized film comprises Hostaphan 2600 48 gauge polyester film which has been vacuum metallized with aluminum to give an optical density of 0.25 ± .05 as measured by a Tobias densitometer. Such film is available from Hoechst Celanese of Greer, South Carolina. The lamination of the metallized film to the Kraft sheet can be done with WC-3460ZZ (polyethylene vinyl acetate copolymer) adhesive available from H.B. Fuller of St. Paul, Minnesota. A paper backing can be provided opposite to the 35 lb. Kraft sheet and fluted with the 35 lb. Kraft sheet laminated to the metallized film. The opposite side of the fluted film is coated with Duracet 12 (a polyvinyl acetate adhesive available from Franklin International in Columbus, Ohio) . Preferably, the Duracet 12 adhesive is applied to have a dry printed weight of 3 to 7 lbs. basis weight (per 3000 sq. ft. or "ream") . A backer sheet of 62 lb bleached Kraft sheet, such as from Rhinelander Paper Company, with Quillon on one side and Duracet 12 adhesive on the non-Quillon side, is used to secure the geometry of the fluted trays. In general, what is desired, if trays are used, is to provide longitudinal extending chambers wherein microwave interactive material is provided in heat conductive relation with at least two and preferably three-four sides of the longitudinal pieces of food. A company which can metallize polyester film to the specification stated is Madico of Woburn, Massachusetts. It is anticipated that a variety of susceptor designs or shapes can be used, to accomplish various effects. Alternate susceptor materials or microwave interactive arrangements may be used. For example, printed susceptors, or alternate susceptor constructions, may be applied to carton 14.

Preferably, a formed and partially fried potato product is used. It is preferably approximately 90% cooked, then inserted into chambers 18 of susceptor 12, which is inserted into carton 14 before being frozen (flash or IQF (individual quick freeze) ) . The microwave reconstitution will heat and cook the potato product the final 10%, to yield a crisp exterior and a preferred final product eating temperature. Freezing could be done before insertion into chambers 18, if desired. Referring again to Figs. 1 and 3, carton 14 generally defines a rectangular shape surrounding susceptor 12. Carton 14 includes a closed end 70, and an open end 72 opposite the closed end 70. Closed end 70 may include one or more vent openings, if desired. Opposing front panel 74 and back panel 76, and opposing first side panel 78 and second side panel 80 are parallel to the parallel direction 22 of food chambers 18 and food items 66. Carton 14 contains susceptor 12 and food items 66 during handling, storage and use. Also, carton 14 engages susceptor 12 to permit handling as a single unit, following cooking, as will be described in greater detail below.

Overwrap 16 surrounds inner construction 11 during storage, handling, and cooking, if desired. Food items 66 and susceptor 12 are placed within carton 14 prior to overwrap 16 being assembled around carton 14. Overwrap 16 is preferably formed from a single sheet of material with two opposed open ends closed shut at first side seam or seal 90, and opposite second side seam or seal 92. A transverse or fin seal 114 closes the sheet of overwrap 16 and links first and second side seals 90 and 92. Preferably, transverse seal 114 is formed first, before side seals 90 and 92 during assembly of overwrap 16 around carton 14. Side seals 90 and 92 are perpendicular or transversely positioned relative to open end 72 of carton 14. The seals can be formed in other locations and directions if desired.

Overwrap 16 further includes top and bottom panels 94 and 96 disposed on opposite sides, and front and back panels 98 and 100 disposed on opposite sides generally perpendicular to top and bottom panels 94 and 96. Preferably, a glue or other adhesive, such as Duracet 12, joins the various seals 90, 92 and 114, except for a vent opening or region 104, in the preferred embodiment of Figures 1-13. A cold seal, or cohesive, may be used, available from H.B. Fuller or Morton International, applied at 1 to 8 lbs. basis weight (weight per 3,000 sq. ft.) . Vent region 104 is optional. However, appropriate venting is desirable either through a vent opening, such as vent 104 and/or other vent openings, and/or via porosity of the sheet material of overwrap 16. Such venting is desirable to allow for hot air and/or steam to escape as it is produced during the microwave heating process of the food items 66. In package 10, vent region 104 is merely folded shut during the manufacturing process, but no adhesive or other mechanical closure is provided to permit vent region 104 to expand open as necessary. During use, hot air and/or steam will escape through vent region 104 in the direction of arrow 105 in Figure 1.

In the closed shut state, each side seal 90 and 92 includes two tucked-in corners, corners 90a and 90b along side seal 90, and corners 92a and 92b along side seal 92. Corners 90a, 90b, 92a and 92b facilitate a fairly tight fit of overwrap 16 around carton 14. The tight fit gives the package an aesthetically pleasing look for the consumer. Corner 92a forms a portion of vent region 104 in the preferred embodiment. The other corners 90a, 90b and 92b are glued shut. Alternatively, one or more of corners 90a, 90b and 92b can remain unglued to form another vent region.

To facilitate opening of overwrap 16 to permit access to the food items contained therein, a tear apparatus is provided. One preferred tear apparatus is a separate tear strip 106 mounted to overwrap 16. To facilitate tearing of overwrap 16 with a sufficiently large opening, a second tear strip 108, as shown in Fig. 2, is provided. Tear strips 106 and 108 strengthen overwrap 16 at their location such that tearing along a predetermined path in overwrap 16 is provided. Overwrap 16 preferably cannot be torn from one side to the other of each tear strip 106 and 108. Instead, tearing is along each tear strip 106 and 108. The strengthening of overwrap 16 facilitates tearing of an appropriate section of overwrap 16 to provide the access opening. To open overwrap 16, a portion of first side seal 90 is gripped at gripping portion 116, shown in Fig. 1, and overwrap 16 is torn by pulling gripping portion 116 toward second side seal 92. Tear strips 106 and 108 made from a pressure sensitive or thermo-activated polymer reinforced film are suitable. Instead of a tear apparatus which tears open overwrap 16, a dispensing opening can be formed in other manners, such as automatically through the use of an appropriately configured seal that opens during microwave heating.

Referring now to Figs. 5 - 9, an example of use of package 10 is shown. Package 10 and the food items contained therein are placed in a microwave oven 140 to cook the food items. After cooking, an opening 118 is formed in overwrap 16 by removal of upper portion 120 when the consumer grips gripping portion 116 and pulls upward and toward second side seal 92. Upper portion 120 is preferably separated from lower portion 122, although it is not required. Lower portion 122 as shown in Fig. 7 contains carton 14 with susceptor 12 and food items 66 contained therein. Lower portion 122 is preferably shaken along with carton 14, susceptor 12 and food items 66 to shake loose any food items which have become stuck to susceptor 12 or carton 14 during manufacturing or cooking. Carton 14 with susceptor 12 is separated from lower portion 122 of overwrap 16 in the direction of arrows 121 leaving behind food items 66 in lower portion 122 as shown in Fig. 8. Seasoning from a packet 124 is added as desired by the consumer. As shown in Fig. 9, the individual food items 66 are dispensed from lower portion 122 of overwrap 16 as desired by the consumer. Lower portion 122 resembles a flexible pouch.

With reference to Figs. 6 - 8, seasoning packet 124 is shown during use. During assembly of package 10, seasoning packet 124 is attached to carton 14, preferably at front panel 74. Seasoning packet 124 is optional, and not shown in Figs. 1 - 3. However, seasoning packet 124 would be located between front panel 74 of carton 14 and front panel 98 of overwrap 16, in Figs. 1 - 3. As best shown in Figs. 6 and 7, seasoning packet 124 is adhesively attached with suitable adhesive 140 to front panel 74 of carton 14. For example, a hot melt H.B. Fuller HM2703 adhesive is appropriate. The adhesive bonds seasoning packet 124 to carton 14 such that packet stays with carton 14 when carton 14 is removed from overwrap 16 as shown in Fig. 7. At that point, the consumer separates seasoning packet 124 from carton 14, and then seasoning packet 124 can be opened and poured onto food items 66, as shown in Fig. 8. The adhesive 140 saves the consumer from having to dig around in lower portion 122 of overwrap 16 for a loose seasoning packet. Use of an appropriate packet construction is desired in the case of hydroscopic materials contained in the packet like salt or salt substitute to prevent caking during storage. A paper/polyethylene/foil (0.000285 inches thick) /polyethylene construction prevents caking of sodium chloride, or mixtures of sodium chloride and potassium chloride. A flow agent like silico-aluminate may be added, if desired.

Referring now to Figs. 10 - 13, constructions of various components of package 10 are shown in greater detail. Referring now to Fig. 10, overwrap 16 is provided initially as a single rectangular sheet 16a. On front surface 101, a glue region 102 is provided along an outer periphery of sheet 16a where glue is applied to form seals 90, 92, 114, except for vent region 104. A preferred glue is a printable, thermo-activated adhesive, such as Duracet 12. This adhesive is preferably applied to have a dry printed weight of 3 to 7 lbs. basis weight (weight per 3000 sq. ft.) to facilitate proper formation of seals 90, 92 and 114.

Tear strips 106 and 108 are attached across sheet 16a. Alternatively, the tear apparatus can include perforations through overwrap 16 as shown in Fig. 14. Steam produced during cooking, and other moisture present, may adversely affect performance of a tear apparatus of perforations in overwrap 16 upon the desired time to tear open overwrap 16, without an appropriate strengthening structure, coating, or treatment. However, perforations are useable in package 10, if desired, as a possible cost effective tear apparatus to effect opening of overwrap 16. Surface 101 forms an inside surface of overwrap 16. Opposite to front surface 101 is a back surface which forms the various panels 94, 96, 98 and 100 and outside surfaces of first and second side seals 90 and 92, and transverse seal 114. Notches 107a and 107b on opposite sides of tear strips 106 and 108 form a tear notch 107 in package 10 once overwrap 16 is assembled, as shown in Fig. 1. Tear notch 107 serves as a tear guide for the consumer to start the tear in overwrap 16 in the appropriate location. Tear notch 107 is preferred, but it is optional. Printed indicia and/or one or more perforations maybe provided to assist and guide the consumer to carry out a proper tearing of overwrap 16.

Referring now to Fig. 11, tear strip 106 is shown in greater detail. Tear strip 106 includes a continuous string, strand or yarn 110 positioned between overwrap 16 and a continuous polymer strip 112 attached with suitable adhesive or other attachment methods to overwrap 16. Tear strip 106 is preferably positioned on surface 101 of sheet 116 thereby positioning strip 106 inside overwrap 16 in package 10. Tear strip 108 is similarly constructed. During use, tear strips 106 and 108 remain with upper portion 120 of overwrap 16 to prevent insufficient tearing of overwrap 16. Preferred tear strips include Scotch brand tear strip tape by Minnesota Mining & Manufacturing Company of St. Paul, Minnesota, product nos. 8605 (glass yarn) and 8604 (polyester yarn) on a polyester backing with a pressure sensitive adhesive. An alternative tear apparatus can include any suitable strip material adhered or otherwise joined to overwrap 16, such as an adhesive backed polymer tape or Kraft paper. Referring now to Fig. 12, carton 14 is shown in an unfolded flat form comprising carton sheet 14a. Carton sheet 14a is a single carton blank, stamped or die cut from a sheet of appropriate material . Once sheet 14a is folded into a rectangular configuration, foldable flaps 126, 128 and 130 cooperate with closed end 70, constructed as a foldable flap, to close the end of carton 14. Vent holes 138 are provided in the flap of closed end 70 for use in proper venting during cold storage and/or heated air/steam release during cooking. Foldable flap 136 is adhesively attached to second side panel 80 with suitable adhesive, such as Duracet 12 or a general purpose adhesive made by National Starch or H.B. Fuller. Foldable flaps 132 and 134 are positioned on open end 72 of carton 14 and project into assembled carton 14. As shown in Fig. 13, flap 134 cooperates with a notch 68 in susceptor sheet 50 to retain susceptor sheet 50 of susceptor 12 within an interior of carton 14. Also, similar notches are provided on an opposite side of susceptor sheet 50 adjacent flap 132. Similar notches are provided with susceptor sheets 52 and 54. The notches engage flaps 132 and 134 positioned within carton 14 to retain susceptor sheets 50, 52 and 54 within carton 14 during tipping of open end 72 of carton 14 downward to remove food items 66 from within carton 14 and susceptor 12. Panels 74, 76, 78, and 80 are foldably interconnected, as shown in Fig. 12.

Carton 14 is preferably constructed from a food grade paperboard material, such as 0.016 inches thick SBS (clay coated solid bleached sulfate) paperboard by Jefferson Smurfit of Brewton, Alabama; 0.016 inches thick bleached Temboard by Tembeck Corporation of Toronto, Ontario; 0.016 inches thick SBS paperboard with extrusion laminated polyester coating 1 mil (0.001 inches) thick by Wesvaco Corp. of Richmond, Virginia or International Paper Corporation of Nashville, Tennessee; or 0.016 inches thick SBS paperboard with printing press applied or paper mill applied release coating such as Coating OPB, available from Michelman Inc. of Cincinnati, Ohio. Carton 14 can be integral with or separate from susceptor 12. In the embodiment shown in Figs. 1-13, susceptor 12 is separate from carton 14 prior to assembly. Referring now to Figs. 3 and 12, a protective sheet 84, such as paper, is positioned on an inside of carton 14 preferably attached to carton 14 to an inside of front panel 74 with suitable adhesive, such as Duracet 12, or other attachment methods. Sheet 84 preferably has an outer surface 86 that will not permit excessive sticking of the food items 66 should any food items come in contact with surface 86, such as if package 10 is oriented such that food chambers 18 are upside down relative to the configuration shown in Fig. 3 during cooking. A Quillon coating by du Pont is one preferred construction.

Overwrap 16 is constructed from a material which does not melt or otherwise deteriorate when exposed to temperatures encountered during heating of the food in the microwave oven. For example, temperatures at the susceptor may be at 350°F or higher. Some plastic overwrap films may melt if adjacent to a susceptor or an outer carton at this temperature. Preferably, the overwrap 16 is constructed from a material which does not retain heat in a manner that would cause excessive handling problems, such as burning possibilities, to the consumer after use, such as may occur with some plastic films. Also, an ability to tear fairly easily is desired with respect to overwrap 16. Food grade paper is one example of a preferred construction for overwrap 16. In particular, a 41 lb. basis weight paper (weight per 3,000 sq. ft.) with a supercalendared surface is one preferred material. Other weight papers are possible. Laminates including a polymeric film(s) with a paper layer(s) are possible, such as will be described with respect to Figs. 15-17. Printed indicia can be located on overwrap 16. Supercalendared paper is suitable in the case of small, detailed type fonts, such as Japanese. A grease resistant construction such as a grease resistant coating may be used, such as a fluorochemical compound like FC807 compound available from Minnesota Mining & Manufacturing Company of St. Paul, Minnesota applied during the paper making process, or grease proof paper, can be used, to reduce or limit exposure of grease to overwrap 16 and/or the consumer while holding lower portion 122 after cooking. A 41 lb. paper with FC807 treatment Kit 10 (high level) is one preferred construction. The use of paper may not allow for extended refrigerated storage since the paper may be moisture and vapor permeable, which could lead to food degradation over time in a refrigerated, but not frozen, setting. Also, paper may not be as durable during handling unless proper care is taken. Plastic films which are sufficiently moisture and vapor impermeable can be refrigerated and handled with less emphasis on causing possible loss of integrity of the overwrap.

From the above description, some general applications and arrangements according to the present invention will be understood. In general, ease of manufacture is facilitated by the convenient configuration of package 10, including susceptor 12, carton 14, and overwrap 16, and the preferred paper overwrap construction. Also, the configuration and construction of package 10 allows for ease of use by the consumer. If desired, the package 10 can be utilized from cold storage to microwave oven without removal or alteration of overwrap 16. Such features are particularly advantageous for automated merchandizing where the packages 10 are stored cold and heated at the selected time by automated machine. Cold storage in overwrap 16 and subsequent placement in a microwave is convenient since only movement of package 10 from one location to the other is needed in order to effect cooking. In addition, overwrap 16 serves as its own serving utensil. The consumer need only open overwrap 16 after cooking, and remove carton 14 and susceptor 12 to facilitate dispensing of the food items 66 from overwrap 16. In this manner, no additional serving dish or utensil needs to be provided. Moreover, overwrap 16, along with carton 14 and susceptor 12, can be discarded after use. Package 10 is useable without susceptor 12, if desired. Also, package 10 is useable without carton 14, if desired. Susceptor 12 or another susceptor is utilized for crisping, toasting or browning a food item, if such is desired. Carton 14 as a partial enclosure facilitates proper cooking of the food items 66 and/or storage of the food items 66 and any susceptor in some settings, such as for french fries. Carton 14 also protects the consumer from contacting susceptor 12, possibly causing a burn. If an enclosed box-like carton 14 is not desired, and protection of the consumer is an issue, tabs or other handling apparatus can be provided with susceptor 12 to reduce contact problems with the consumer. Various food items, including non-elongated food items can be utilized in an appropriately configured package 10, such as onion rings. Indeed, arrangements according to the invention may be used, to advantage, for heating a wide variety of food products.

Referring now to Figs. 15 - 17, an alternative preferred embodiment of a microwave food heating package 200 is shown including an inner construction 11 as described previously, and an alternative overwrap 216 instead of overwrap 16 described previously. Overwrap 216 is a laminate including an inner paper layer and an outer polymeric film layer. Overwrap 216 surrounds inner construction 11 during storage, handling, and cooking, if desired. Overwrap 216 is formed from a single sheet of material with two opposed open ends sealed shut at first side seal 290, and opposite second side seal 292. A transverse or fin seal 314 closes the sheet of overwrap 216 and links first and second side seals 290 and 292. Such construction around carton 14 with open end 72 and closed end 70 is similar to the construction described previously with respect to overwrap 16.

Overwrap 216 further includes top and bottom panels 294 and 296 disposed on opposite sides, and a front panel 298, and an oppositely disposed back panel. Preferably, a glue or other adhesive, such as Duracet 12, joins the various seals 290, 292, and 314, except for two vent regions 304 and 304a in the embodiment of Figs. 15 - 17. Duracet 12 is a heat seal requiring thermo-activation of the adhesive to form the seal. Cold seal adhesives, or cohesives, may be used instead, if desired, to form the seals with pressure only without the need for heat.

A second vent region 304a in addition to vent region 304, instead of just the single vent region 104 of package 10 described above, is desirable for package 200, in part due to the polymeric component of overwrap 216. The venting is generally desirable to allow for hot air and/or steam to escape as it is produced during the microwave heating process of the food items. In package 200, vent regions 304 and 304a are merely folded shut during the manufacturing process, but no adhesive or other mechanical closure is provided to permit vent regions 304 and 304a to expand open as necessary. During use, hot air and/or steam will escape through vent regions 304 and 304a in the direction of arrows 305 and 305a. In the closed shut state, each side seal 290 and 292 includes two exposed upper corners 290a and 292a, and two tucked in lower corners 290b and 292b. Upper corners 290a and 292a are not tucked in and each defines a higher profile pull tab than tucked in lower corners 290b and 292b. Both of upper corners 290a and 292a form a portion of vent regions 304 and 304a, respectively, in the embodiment of Figs. 15 - 17. Lower corners 290b and 292b are glued shut, along with the rest of side seals 290 and 292, except for vent regions 304 and 304a. Alternatively, one or both of lower corners 290b and 292b can be left unglued so as to form vent regions as tucked in corners or untucked corners. Package 200 includes a tear apparatus to facilitate opening of overwrap 216. The embodiment of Figs. 15 - 17 includes a tear apparatus having a separate tear strip 306 mounted adjacent a line of weakening, preferably a perforation line 316, comprised of linear slits, such as shown in Fig. 17. To facilitate tearing of overwrap 216 with a sufficiently large opening, a second tear strip 308, as shown in Fig. 16, is provided. Tear strip 308 also is mounted adjacent a perforation line in a similar manner as tear strip 306. Instead of tear strips 306 and 308 being positioned along top panel 294 of package 200, as is the case with package 10 described above, tear strips 306 and 308 are positioned across front panel 298 and the opposed back panel, respectively. Like package 10, tear strips 306 and 308 extend across side seals 290 and 292.

To open overwrap 216, a portion of first side seal 290 adjacent upper corner 290a is gripped at gripping portion 316, shown in Fig. 15, and overwrap 216 is torn by pulling gripping portion 317 toward side seal 292. Tear strips 306 and 308, along with the perforation lines, allow tearing open of overwrap 216 to allow access to carton 11. The presence of the perforation lines and the tear strips 306 and 308 together help facilitate appropriate tearing of an overwrap laminate comprised of both paper and a polymeric film. Specifically, the perforation lines help facilitate proper tearing of the polymeric film.

Referring now to Fig. 16, overwrap 216 is provided initially as a single rectangular sheet 216a. On front surface 301, a glue region 302 is provided along an outer periphery of sheet 216a where glue is applied to form seals 290, 292 and 314, except for vent regions 304 and 304a, and any other desired vent regions or other non- sealed areas. One preferred glue is Duracet 12, described previously, and preferably applied to have a dry printed weight of 4 to 7.5 lbs. basis weight (weight per 3,000 sq. ft.) . Figure 16 illustrates example vent regions 304b and 304c that would be left as gaps without adhesive to form optional vent regions at lower corners 290b and 292b. Tear strips 306 and 308 are attached across front surface 301 of sheet 216a. As shown in Fig. 17, tear strip 306 is positioned such that tear string 310 between polymer strip 312 and front surface 301 is such that the tear string stays with the upper portion of overwrap 216 once torn away from, and partially or completely separated from the lower portion of overwrap 216 useable to hold and dispense the cooked food items. Tear strip 308 is positioned in a similar manner with respect to the line of perforations associated with tear strip 308. While polymer strip 312 is shown in Figure 17 as partially overlapping perforation line 316, it is important the overlap not interfere with the tearing operation. Some overlap is acceptable. Too much overlap may hinder or prevent proper tearing if the polymer strip stays attached to the lower portion of the overwrap. Polymer strip 312 positioned above (spaced from or just touching in Fig. 17) perforation line 316 is advantageous for this reason.

Notches 307a and 307b on opposite sides of tear strips 306 and 308 form a tear notch 307 in package 200 once overwrap 216 is assembled, as shown in Fig. 15. Tear notch 307 serves as a tear guide for the consumer to start the tear in overwrap 216 in the appropriate location. Preferably, tear notch 307 is in alignment with the lines of perforation associated with the tear apparatus. Tear notch 307 is preferred, but it is an optional feature. Also, tear notches 307a and 307b can be formed on overwrap 216 prior to assembly around carton 14, during assembly, or after assembly.

A preferred construction of overwrap 216 is a lamination of a polymeric film layer, adhesive, and a grease-resistant paper, where the polymeric film layer is bonded to the paper. In the alternative preferred embodiment of Figs. 15 - 17, the polymeric film layer is positioned on an exterior of package 200 relative to the paper layer. The polymeric film layer is selected so as to achieve suitable performance in a microwave without degradation from heat from the susceptor or the food items. Preferably, the polymeric film layer includes a polyester film, such as Hostaphan 2600 48 gauge polyester available from Hoechst Celanese. Preferably, the inner grease-resistant paper layer is a 35 lb. basis weight paper (weight per 3,000 sq. ft.) Staynles grade paper with FC807 treatment Kit level 7 available from James River Corporation of Richmond, Virginia. A suitable adhesive for joining the polyester film layer to the paper is H.B. Fuller 3460ZZ adhesive, noted above as also being suitable for use in the construction of susceptor 12. It is to be appreciated that other layers could be positioned between the paper and the outer polymeric film layer, and the paper could be bonded to the polymeric film layer in other manners besides the adhesive. It is also to be appreciated that further layers could be added to the paper and/or to the polymeric film layer. While the use of paper is preferred, other overwraps not including paper could be employed to contain the food item(s) and any inner construction 11 during cooking, and where the overwrap later serves as a serving container to hold and dispense the food item(s).

Fig. 18 shows in cross-sectional schematic side view an alternative microwave food heating package 400 where overwrap 402 includes paper 404 enclosing inner construction 11, and a strip of an outer polymeric film layer 406, such as polyester, laminated to a portion of paper 404. This allows steam to escape through the upper portion 407 of paper 404, and protection of the bottom surface 408 of package 400 where moisture can condense. In Fig. 18 only transverse seal 410 is shown. The overwrap of the present invention, whether paper, a laminate of paper and a polymeric film, or another construction, is useable for storage, handling, and cooking of food items, and subsequent dispensing of the food items after cooking. Paper in the overwrap does have a tendency to absorb grease and moisture during use in this manner. If too much grease or moisture is absorbed, the overwrap may take on an undesirable appearance or it may perform inadequately. Grease may get on the consumer's hands, and/or the strength of the overwrap may deteriorate so much that it tears too easily. The presence of an outer polymeric film layer, such as described for the embodiment of Figs. 15 - 17, strengthens and reinforces the paper layer, and keeps any grease or moisture from soaking through the overwrap. The paper is still desirable for its grease and moisture absorbing properties. The paper helps keep grease and moisture away from the food and the consumer's hands. Also, the paper can be printed on fairly easily with package labeling and instructions prior to lamination to the polymeric film layer. The polymeric film also protects and seals the printing on the paper during handling.

Claims

WHAT IS CLAIMED IS;

1. A microwave food heating package for a food item comprising: an inner construction including: a susceptor which heats in the presence of microwave energy; and a carton positioned around the susceptor, the carton defining a partially enclosed shape with at least one open end, the food item positioned in the carton adjacent the susceptor; and an overwrap comprising paper enclosing the inner construction, the overwrap having two longitudinal seals, the two seals on opposite sides of the carton and extending in a direction transverse to the open end of the carton.

2. The microwave food heating package of claim 1, wherein the overwrap includes a polymeric film layer bonded to the paper wherein the paper is between the polymeric film layer and the inner construction.

3. The microwave food heating package of claim 2, wherein the polymeric film layer comprises polyester.

4. The microwave food heating package of claim 2, further comprising a tear apparatus oriented to open the overwrap.

5. The microwave food heating package of claim 4, wherein the tear apparatus includes a tear strip including a polymeric construction mounted to the paper of the overwrap and extending from the first seal to the second seal, the tear apparatus further including a perforation line including perforations extending through the overwrap.

6. The microwave food heating package of claim 2, further comprising a vent opening formed in a portion of one of the seals of the overwrap.

7. The microwave food heating package of claim 6, further comprising a second vent opening formed in a portion of another one of the seals of the overwrap.

8. The microwave food heating package of claim 2, wherein the polymeric film layer is a strip only covering a selected portion of the paper.

9. The microwave food heating package of claim 1, wherein the susceptor defines a plurality of chambers extending in a parallel direction, each chamber sized to receive a food item, the parallel direction of the chambers being transverse to the open end of the carton.

10. The microwave food heating package of claim 1, further comprising a vent opening formed in a portion of one of the seals of the overwrap.

11. The microwave food heating package of claim 10, further comprising a second vent opening formed in a portion of another one of the seals of the overwrap.

12. The microwave food heating package of claim 11, further comprising third and fourth vent openings formed in the seals, each vent opening positioned at opposite ends of each of the seals.

13. The microwave food heating package of claim 10, wherein the vent opening is positioned at an end of the seal, and further comprising a tear apparatus oriented to open the overwrap, wherein the end of the seal forms a pull tab for tearing open the overwrap with the tear apparatus.

14. The microwave food heating package of claim 1, further comprising a tear apparatus in the overwrap.

15. The microwave food heating package of claim 1, further comprising a seasoning packet affixed to the carton.

16. A microwave food heating package for at least one food item comprising: an inner construction for holding the food item, the inner construction including: a susceptor which heats up in the presence of microwave energy; and a carton positioned around the susceptor, the food item positioned in the carton adjacent to the susceptor; an outer overwrap enclosing the inner construction, the overwrap having at least one open end; a closure apparatus closing at least a portion of the open end to define a seal, and wherein the open end also defines a vent opening during cooking; and a dispensing opening apparatus in the overwrap for forming a dispensing opening in the overwrap sized to dispense the food item.

17. A microwave food heating package for at least one food item comprising: an inner construction including; a susceptor which heats up in the presence of microwave energy; and a carton positioned around the susceptor, the food item positioned in the carton adjacent to the susceptor; an outer overwrap enclosing the inner construction; and a tear apparatus in the overwrap.

18. A microwave food heating package for at least one food item comprising: an inner construction including: a susceptor which heats up in the presence of microwave energy; and a carton positioned around the susceptor, the food item positioned in the carton adjacent to the susceptor; an outer overwrap enclosing the inner construction, the overwrap having at least two opposing open ends; and a closure apparatus closing at least a portion of the two open ends to define two parallel seals, and wherein at least one of the ends also defines a vent opening during cooking.

19. A microwave food heating package for at least one food item comprising: an inner construction for holding the food item; an outer overwrap enclosing the inner construction, the overwrap having at least two opposing open ends; a closure apparatus closing at least a portion of the two open ends to define two parallel seals, and wherein at least one of the ends also defines a vent opening during cooking; and a tear apparatus in the overwrap.

20. An overwrap for use in packaging a microwavable construction for holding food comprising: a sheet of overwrap material having a front surface, a back surface and two pairs of parallel opposed edges; and an adhesive positioned on an outer periphery of the first surface adjacent to each of the two pairs of opposed edges, so as to define at least one gap for forming a vent opening along one edge.

21. The overwrap of claim 20, wherein the overwrap material comprises paper.

22. The overwrap of claim 20, further comprising a tear apparatus extending from a first edge to a second edge of one of the pairs of opposed edges.

23. A method of cooking food comprising the steps of: a) providing a microwave food heating package including a susceptor, a food item adjacent to the susceptor, and an overwrap around the susceptor and the food item; b) exposing the microwave food heating package to microwave energy to heat the food item; c) after heating the food item, forming an opening in the overwrap; and d) removing the susceptor from the overwrap through the opening, leaving the food item contained at least partially in the overwrap.

24. The method of claim 23, further comprising the step of venting heated air and steam from an interior of the overwrap to an exterior through a vent opening.

25. The method of claim 23, wherein the step of forming the opening includes the steps of providing a tear apparatus in the overwrap, and pulling the tear apparatus away to tear open the overwrap.

26. The method of claim 23, wherein the microwave food heating package includes a carton positioned around the susceptor, the food item positioned in the carton adjacent to the susceptor, and the overwrap positioned around the carton, the method further comprising the step of removing the carton through the dispensing opening after heating the food item.

27. The method of claim 26, wherein the steps of removing the susceptor and the carton through the dispensing opening after heating the food item are done simultaneously.

28. The method of claim 26, wherein the step of providing the microwave food heating package includes providing the susceptor with a plurality of food chambers, wherein a food item is positioned in each food chamber, and the step of removing the carton and the susceptor including leaving the food items contained at least partially in the overwrap.

29. A method of cooking food comprising the steps of: a) providing a microwave food heating package including a carton, a food item positioned in the carton, and an overwrap around the carton; b) exposing the microwave food heating package to microwave energy to heat the food item; c) after heating the food item, forming an opening in the overwrap; and d) removing the carton from the overwrap through the opening, leaving the food item contained at least partially in the overwrap.