JPH01169240A - Flexible package for microwave cooking - Google Patents

Abstract

PURPOSE: To enable cooking of a foodstuff packed in a package receiving microwave oven radiation beams by preparing a pouch suitable for filling the foodstuff therein in such a manner that a blank has adhesive agent areas and a plurality of folding lines are formed for making the blank foldable and the adhesive agent areas are adhered to each other. CONSTITUTION: A blank 10 includes panels 12, 14, 16, 18, 30, 34 and also has folding lines 22, 24, 26 extending in a vertical direction and folding lines 28, 32 extending in a horizontal direction. On the panel portion 18, an adhesive agent is provided such that it faces a reader. A polyethylene terephthalate(PET) film 40 faces a viewer and is constructed such that it faces the inside of a pouch. Drooping lids 30, 34 are folded upwardly at an angle of 90 deg. and the side panels 14, 16 are folded toward the center. In assembling, the adhesive agent on the panel 18 is fixedly secured to an ornamental portion at a right-side free peripheral brim of the panel 16 thus forming a mating portion. The adhesive agent on the panel 18 is adhered to a PET portion along the right-side free peripheral brim of the panel 16 and is folded about the folding line 22. Finally, a foodstuff is packed in the pouch before the outer periphery is completely sealed.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a package for microwave cooking of food, and in particular, a package for cooking food with microwaves so that at least a portion of the food is browned or crispy. This is related to the package.

[Prior art and problems to be solved by the invention] Conventionally,
Food packages are known that can be placed directly into a microwave oven to cook the food without removing the food from the package. Furthermore, there has been conventionally known a method in which food to be cooked in a microwave oven is placed in a package provided with a microwave-interactive material and browned using microwaves. This microwave-interactive material becomes extremely hot during exposure to microwave energy in a conventional microwave oven, causing food that is in direct thermal contact with the microwave-interactive material to brown or crisp. Burnt. An example of a food package that browns or crisps food in this manner is disclosed in Blastad, US Pat. No. 4,287,420.

A package according to the invention provides a thermal heating effect for containing food during cooking or heating in a microwave oven, heating the food to a high enough temperature to brown or crisp the surface of the food. In contrast to the prior art, all the packaging forms according to the invention are characterized in that the package and the food product can be easily installed and positioned in the microwave oven, and all the packaging forms according to the invention serve a similar purpose. The objective is to utilize materials more effectively than prior art packages. Also,
The present invention provides a package form that is easier to manufacture, requires fewer manufacturing steps, and takes less time to manufacture than various prior art packages for browning and crisping with microwaves. Most importantly, the packaging form according to the invention provides better cooking results for many types of food products than previously available packaging.

The packaging form according to the invention is highly suitable for preparing foods with undercooked or tough crusts, such as pizza, bread, dessert pastries, breaded fish fillets and ground chicken pieces.

These foods are not normally cooked properly in a microwave oven, primarily due to the lack of heating effects present in a typical cooking environment such as a microwave oven. .

The package of the present invention may be formed in a packaging form such as a sachet, bag or container, or may be formed in other forms as described below. All packaging forms according to the invention have a substantial packaging portion made of a flexible laminate material that has a microwave interaction layer that allows conduction, convection and and/or has the inherent property of exchanging microwave energy for thermal energy that can be transferred by radiation. In many embodiments of the invention, heating occurs in a total of three heat transfer modes. The flexible laminate material that provides this heating effect can be made of a variety of materials. In the preferred embodiment, paper and lightly metallized polyester fibers constitute the laminated flexible material; however, the present invention is directed to the selection of specific materials for the flexible microwave-interactive laminated material. It is not limited to. This allows the entire package to be made of a flexible laminated material that functions to provide a heating effect, or can be used in conjunction with other flexible materials, or a relatively rigid material such as cardboard. It can also be used with hard materials. In each case, an important feature of the design of the package of the invention is that the area covered by the microwave-interactive layer ensures that there is no mutual contact between the flexible part of the package supporting the microwave-interactive layer and the food product. It should be larger than the size of the food on the area.

It is important to note here that the microwave interaction layer does not have to cover the entire area of the flexible portion of the package; however, the area covered by the microwave interaction layer must always extend beyond the food contact area.

It is also possible for the microwave-interactive layer to be provided in the form of a discontinuous pattern, such as strips or islands, and in such cases the entire area covered by such pattern is contacted by the food product. shall exceed the area covered by the

Another important feature of the design of the package according to the invention is that the package containing the food product occupies more space in the microwave oven than the volume of the food product at any time during microwave cooking.

Two important features of the above-mentioned design belonging to all of the various forms of the package according to the invention are that all the package forms have a microwave-interactive layer that covers an area larger than the area of the food that comes into contact with the part of the package. and all packaging forms must have an internal volume that is greater than the maximum volume of the food. The combination of these design features and the use of flexible materials to provide a microwave interactive layer provides a package according to the invention with advantages over packages obtained with prior art concepts and methods. The resulting package provides a food cooking environment within the microwave oven, combining controlled heating effects on the surface of the food with the rate of microwave heating inside the food.

Considerable improvements over prior art packages are obtained through the combination of the use of a flexible carrier material for the microwave interaction layer and an extended area of the cover of the microwave interaction layer that extends beyond the area contacted by the food product. It will be done. The combination of these two features of the package allows for the proximity of the microwave interactive layer to the edges of the food product, regardless of the exact shape of the food product. This allows the edge parts of the food product to be given a heating effect as well as the area or bottom that is in direct contact with the microwave interaction layer.

Without this transfer of heat energy to the edges of the food, many foods have a high moisture content along their edges.
Or exhibit an undesirable soggy appearance. The reason for this is that the edges are relatively cool compared to the part of the food product that contacts the microwave-interactive material, and moisture migrates to the cooler part of the food product. Of course, the heating effect on the food can be further enhanced by coating the entire inside of the package with a microwave-interactive layer, and the package can be turned over in the middle of the microwave cooking cycle to provide equal cooking effect on both sides of the food. Complete coverage is particularly important in the embodiments of the invention that are provided.

The relationship between the maximum volume of the food and the internal volume of the package is such that a high temperature space exists around the food so that the food can be cooked in an environment similar to typical (non-microwave) cooking conditions. is necessary. Package according to the invention
The foam may be closed as a whole to allow moisture from the food to create a humid, hot air environment during cooking, or a portion of the package may be open to allow moisture to escape out of the package. A relatively dry, hot air environment may be maintained. French bread
It is particularly important to provide a hot space above the food for foods where the top surface may stick to the inner surface of the package, such as pizza or frozen pastry foods.

The package form of the present invention relies entirely on the use of flexible materials forming the microwave interaction layer. By using flexible materials to achieve this functionality, the various packaging forms of the present invention can be used with irregularly shaped food products to consistently position the microwave interactive layer along the surface of the food product. Can be done. Additionally, the packaging form of the present invention generally uses less material than other relatively rigid packaging forms, reducing manufacturing costs and reducing the space required to house the package before it is filled with food. can be done.

Also, pouches, containers or bags made of flexible stock are relatively easy to hold open for filling with food.

In some cases, the materials for making the packaging forms of the present invention can conveniently be shipped in rolls and formed into pouch-like shapes at the food packaging site.

After careful consideration and analysis of packaging forms and concepts according to the prior art, there is no combination of the main elements of the package of the present invention and therefore the great advantages obtained by microwave cooking of food in the package according to the present invention. cannot be obtained in traditional packaging form. Numerous prior art patents disclose the use of microwave-interactive materials to provide surface heating effects in microwave food packaging, but in many cases the microwave-interactive materials are made of metals such as aluminum. Thin vacuum deposited layer or polyester film. In many cases in the prior art, a vacuum-deposited metallized film is affixed to a rigid support material, such as cardboard, to form a self-supporting package as a whole, allowing microwave interaction to follow the shape of the food product. There is no way for the layers to be located. Examples of such rigid self-supporting non-flexible food packages are U.S. Pat. No. 4,555,605 (Brown et al.), U.S. Pat. and U.S. Patent No. 4,594,492 (Maroszek) and U.S. Patent No. 4,641,005 (Seyfarth).
stated in the specification. Maroszek's patent seeks to eliminate the disadvantages of rigid cardboard packaging through package design, specifically one or two packages in which cardboard is formed into a spring shape and attached with a vacuum-deposited metallized polyester film. food is kept in constant contact with the inner surface of the While this clearly shows some effectiveness, Maroszek's packaging concept does not eliminate the drawbacks of rigid packaging forms that do not conform to the shape of the food, especially when the food is irregularly shaped. In this case, the above-mentioned drawbacks become a problem. Unlike the rigid, self-supporting packaging forms described above, some prior art packages are constructed from relatively flexible materials to provide a surface heating effect to the food during microwave cooking. ing.

Such a flexible package is described in U.S. Pat. No. 4.267.
No. 420 (Plastalad), U.S. Patent No. 4.553,0
No. 10 (Polar et al.) and U.S. Patent No. 4.841,0
Although it is disclosed in No. 05 (Seyfarth),
None of these prior art flexible packages have the essential features of the package of the present invention. Plastarad's US patent merely discloses a wrapper-shaped package that is in direct contact with the food product at all points. This Plastalad wrapper does not create a hot air space around the food. Plastalad's wrapper-shaped packaging does not heat the food by convection or radiation, which limits the packaging's ability to produce microwave cooking results similar to those obtained by common cooking methods. be. Polar's package is specifically designed as a microwave popcorn package, with a very small area at the bottom of the package coated with a "microwave converting" material, over the entire area coated with this material. The microwave conversion material is configured to produce a surface heating effect on the layer of popcorn kernels. Polar packages do not extend the area covered by the microwave conversion material beyond the area contacted by the food product, ie, popcorn kernels. Additionally, the microwave conversion material in Polar's bags is in all cases attached to the flat horizontal walls of the package, with a shape that brings the microwave conversion material close to the edges of the food and conforms to the surface of the food. It has not become.

Clearly, these considerations, which are essential to the present invention, were not included in the design of Polar's microwave popcorn package. The Seyfarth patent discloses a packaging material that is very similar in nature and function to Brastad's packaging material. Similar to Brastad's wrapper form package, the package form presented by Seyfarth lacks the important feature of the hot space around the food product provided by the package form of the present invention.

The packaging form of the present invention is advantageously used for frozen foods, cold foods and foods stored at room temperature.

Furthermore, the packaging form according to the invention can be used in fast food services, cafeteria services and similar food outlets, where food is prepared, placed in sachets, held for a period of time before serving, Can be reheated in the microwave upon delivery. This reheating step brings the food product back to the desired temperature for consumption and provides the desired surface condition and color for maximum appetizing. Alternatively, a reheating step can complete the cooking of the food product if the food product is only partially cooked before serving.

In either case, the package form of the present invention allows for rapid internal heating of the food by microwave energy, as well as the heating effect of the cooking environment inside the package on the surface of the food, making it possible to reheat the food by microwaves. Ideal if. The sachets, bags and containers of the present invention are particularly suitable for fast food restaurants, convenience stores and the like because of the relatively low cost of the packaging and the packaging form used to handle food products. is suitable overall and provides an excellent combination of thermal and microwave cooking effects. Other commercially available packages do not provide all of these benefits in a single package.

[Means for Solving the Problems] First, with particular reference to FIGS. 1 to 4, 10 indicates a unit blank, from which a pouch according to the present invention is formed. As shown in FIG. 4, the blank is generally flat and formed of multiple layers, from one surface thereof to the other a polyethylene terephthalate (PET) layer 40;
- Laminated in this order are a layer of microwave-interactive material 42 whose temperature increases when exposed to microwave radiation from a microwave oven within the membrane, an adhesive layer 44 and a paper layer 46; Adhesive layer 44 functions to secure waste paper 4B to the layer of microwave interactive material.

Specific combinations of materials suitable for producing a laminate structure such as that shown in FIG. 4 are shown below.

A metal coating, such as aluminum, thin enough to produce a surface heating effect on the food product by the desired interaction with microwave energy, as described in Seyfarth U.S. Pat. No. 4,641,005. A lightly metalized polyester film with. Suitable polyester films are of the type sold under the trade names Mylar or Melinex, and in particular are biaxially oriented polyester films. For use in the practice of this invention, a polyester film is provided with a vacuum deposited layer of aluminum such that the optical density of the aluminum coating is within the general range of 0.15 to 0.30;
The thickness of the polyester film generally ranges from 0.5 to 2.0 mils. A lightly metallized polyester film as described above forms the combined laminate of layers 40 and 42 shown in FIG.

Uncoated bleached white paper of the type known as uncoated offset paper having a basis weight in the range of about 20 to 80 pounds per 3000 square feet. The thickness is about 8~. Paper stock up to 10 mils is flexible enough to serve as a carrier or support material for the microwave-interactive material in this invention.

The adhesive that creates a heat-resistant bond between the metallized polyester film and the paper is a water-based adhesive such as:

Lamination adhesive type % type % RHOPLEX (trademark) N-103
1 Acrylic Latex 375 lb Cymel (Trademark) 325 Melamine-Formaldehyde Crosslinker 11.5 lb Isopropyl Alcohol 11.5 Bond Water
23 Bond (the above three components were premixed before combination with the acrylic latex).

) Diamond ShalIrock Chemicals Corporation (Diamond ShalIrockChe
7 T-7 Star N manufactured by mlcals Co.
XZ Deformer 3 oz bottle (pre-dispersed in an equal amount of water) The combination of materials described above was prepared into a laminated structure suitable for use in the package form of the present invention using a common wet bond laminator. can be converted. In a lamination machine such as that described above, an adhesive is applied to the paper substrate or the metallized surface of the film, or both, the paper and film are then joined with a pressure cannulation, and the lamination machine operates approximately 200 to 800 feet/ft. It is driven at a speed of 1 minute.

Suitable adhesive coverage is usually in the range of 2 to 5 pounds per 1000 square feet, with a typical level of about 3 pounds per 1000 square feet being applied by a 110 line gravure applicator roll. After the paper and film are sandwiched with the adhesive layer between pressure cannulae, the laminate is passed through a hot air curing point to cure the adhesive bond. Kiln temperature is 300-60
For a laminate running speed of 0 feet/min, approx.
0 to 500 or less is suitable. After finally leaving the curing point and passing over cooling rolls, the laminate is generally wound up again.

As will be understood, the scope of the invention is not to be limited to the specific materials and methods described above for making microwave interactive materials. Other materials can be used, and the manufacturing method need not use laminates in all cases. The foregoing description is provided only to provide an understanding of the manufacture of one type of flexible microwave interactive material suitable for use in the packages of the present invention.

Blank 10 includes panels 12, 14.16, 18.30 and 34. 22, 24 and 26 indicate vertically extending fold lines as shown in FIG. 1, while 28 and 32 indicate horizontally extending fold lines. As shown in stippling, panel portion 18 is provided with adhesive facing the reader. The PET film 40 faces the viewer in Figure 1 and is configured and arranged to be on the inside of the pouch. Panel 12 may include a clear plastic piece 3G for viewing food.

FIG. 2 shows an intermediate step in manufacturing or forming the pouch, in which it will be noted that the flaps 30 and 34 are folded upwardly by 90° and the side panels 14 and 16 are folded toward the center. be. During assembly, as shown in FIG. 2, the adhesive on panel 18 adheres to the modified portion of the right free edge of panel 16 (shown extending vertically in FIG. 1), thereby sealing the seam. form. Panel 1
The adhesive on PE 8 runs along the right free edge of panel 16.
It is glued to the T part, and as shown in Figure 3, the fold line 22
can be folded around.

Adhesives suitable for forming the sachet seam should exhibit good bonding properties to both the paper surface and the opposing polyester film surface. In addition, the adhesive is made of polyester with microwave energy.
The heat is converted into heat by a thin vacuum-steamed aluminum coating on the film, which exhibits sufficient heat resistance to ensure that the seam holds even when the packaging material is heated to high IH, such as below 400 °C. It is necessary.

Adhesives must be suitable for food packaging and must, of course, be readily compatible with intra-membrane equipment used to form sachets, bags, containers and similar packaging forms. It is. In view of all of the foregoing, adhesives suitable for the present invention are manufactured by Air Products and Chemicals, Inc.
IRFLEX® 421, a self-crosslinking, water-based vinyl acetate-ethylene copolymer adhesive manufactured by Chemicals, Inc. This adhesive is applied to the end flaps (3) of the sachet according to the invention.
It is likewise suitable for sealing 0) and (34).

Figure 3 shows the completed pouch. As will be clear from the description below, the food product is placed inside the pouch before finally sealing the outer periphery completely.

In FIG. 5, numeral 10 indicates a pouch of the present invention, and as shown in the drawing, the pouch is a microwave chamber 5 of a general microwave oven.
It is set within 0. 52 indicates a food product, typically a frozen food product such as a frozen pizza having a pie crust on the bottom and cheese on the top. 54 indicates the space above the food. As shown in the figures, the pie crust or bottom of the food product 52 is in direct thermal contact with the microwave interactive material.

During the heating treatment with microwave energy in the chamber 50,
The microwave hits the pouch and a portion of the microwave energy passes through the microwave-interactive material (the remaining three laminated elements are transparent to microwaves at this frequency). This passing energy hits the food and acts on it in the manner of conventional microwave heating. Another portion of the microwave energy generated by the klystron or other generator in the microwave oven is absorbed by the microwave-interactive material, increasing the temperature of the microwave-interactive material. Since the volume of the sachet 10 is larger than the volume of the food product 52, the space 54 is formed by high-temperature steam, most of which is water vapor. This heated water vapor can contact irregularly spaced surfaces of the food product, thus helping to evenly heat the food product.

Foods in direct thermal contact with microwave-interactive materials5
The bottom of the plate 4 is browned or crispy due to the temperature increase of the microwave interaction layer 42.

For this reason, the pouch 10 described above was described as having a layer of microwave interactive material 42 over its entire surface. It should be noted that in some applications, the primary panel 12 and the secondary panel 14. l(i (
(which together effectively form a panel) are both provided with interactive materials.

For example, only panel 12 can be provided with an interactive material during formation of the laminate. As is further clear, the interacting material need not be a continuous layer, but strips,
Or it can be provided in essentially different island-like layers.

Various packaging forms within the scope of the present invention are sealed to provide a sealed environment for the food during microwave cooking, thereby maximizing the convective heating effect provided by the microwave interaction layer, and also allowing the food to The moisture vapor generated is retained within the package. The entire sealed pouch is shown in FIG.

Other examples that may be more desirable for certain foods include:
During the microwave cooking process, the package can also be opened at certain times to allow moisture generated from the food to escape. For example, as shown in FIG. 7, one end of the pouch can be opened.1. Alternatively, both ends of the sachet can be opened during cooking, as shown in Figure 8, or the sachet can be threaded either above the food or along the sides of the sachet, as shown in Figure 9. Pores (60) may also be provided. Other examples within the scope of the invention include:
At least a portion of the adhesively sealed area of the sachet may be configured to soften upon heating, in particular due to the heat generated by the microwave-interactive material, such that the sachet can be opened during cooking. This type of self-opening seal can also be achieved using a hot melt adhesive, such as an ethylene-vinyl acetate hot melt adhesive, which has a softening point of about 200F. Figure 10 shows a pouch with a seal (70) provided in the manner described above. FIG. 11 shows another type of self-venting package within the scope of the present invention. In this example,
The vent hole (80) is covered by a closure piece (82) sealed in place by an adhesive having a low softening point as described above.

One of the advantages that the package form according to the invention has over prior art packages is that it is easy to place the food in the microwave during installation and removal from the microwave after cooking, especially at intermediate points during cooking. The point is that it is easy to change the position and direction of the device. Generally, the package form of the present invention has an enlarged area, such as a pouch end seal, which provides a convenient means for lifting and rotating the package. If desired, an auxiliary closure or handle can easily be provided on the main element of the sachet, container or bag according to the invention. Furthermore, the parts of the package that act as means for lifting or rotating the package are not provided with a microwave-interactive layer, so that said parts of the package do not get too hot after the package is removed from the microwave. can do. Figure 12 shows a pouch with auxiliary handles (90) and (92) of the type described above.

It is generally advantageous for foods that are essentially the same on both sides, such as watsufuru or breaded fish fillets, to be completely flipped during microwave cooking. Coating the pouch- or container-shaped package with a microwave-interactive layer on both sides makes it ideal for this type of food. For example, a sachet coated on its entire inner surface with a microwave-interactive layer can cook breaded fish fillets evenly on both sides, and the reason for this is that during microwave cooking the sachet can be completely turned over at the center point. This is because it can be done.

This method allows each surface of the food to be brought into contact with the high heat surface provided by the microwave interactive layer during part of the cooking process, and also exposes each surface of the food to the hot air in the sachet for a certain period of time. You can also do it. This provides an overall cooking effect that is not possible with prior art microwave food packages, thereby providing a browning or crisping effect on the food.

The packaging form according to the invention can be provided with more than one chamber or enclosed space for containing the food product. For example, a pouch having multiple chambers may contain individual portions of the same food product in each chamber, or alternatively, each chamber may contain a different type of food product. In the latter case, it is not necessarily necessary to utilize the same microwave interaction layer in each chamber, nor does it necessarily require uniform microwave interaction layer coatings. Figure 13 shows a two-chamber pouch having two chambers (100) and (102) of the same size.

Multi-compartment sachets, bags or containers may also be used to position the food product elevated above the food support surface of the microwave oven. For example, as shown in FIG. 14, a two-chamber pouch has a first chamber (110) for storing food and a second sealed chamber (112) that expands when the air or moisture contained inside is heated during microwave cooking. ). Such a self-lifting two-chamber pouch is installed in a microwave oven with the first chamber containing food located above the expansion chamber. A controlled amount of water can also be placed in the expansion chamber to ensure proper expansion of the second chamber, which allows the chamber containing the food product to be at the appropriate height during microwave cooking. According to the invention, such a self-lifting two-chamber pouch is provided with a microwave interaction layer at least in the food insertion chamber.

In accordance with the present invention, a package form can be placed in a microwave oven with a food product therein, the food product positioned above a supporting surface, or the package and food product oriented at a particular location in the microwave oven. can be configured to facilitate For example, as shown in Figure 15, the sachet may be provided with a hanging portion (120), which allows the package containing the food product to be hung in a vertical position from a hanger within the microwave oven. Another packaging form with special positioning means is obtained by a two-chamber pouch with a flexible section (130) joining the two chambers. Such a package form can be installed in a microwave oven in an inverted V-shape with the flexible part at the top of the figure 7 and the two chambers in an inclined vertical position, as shown in Figure 16. can.

As previously mentioned, not all embodiments of the present invention are entirely flexible packages. A package with a package portion made of a rigid material can have a microwave interactive layer and a flexible material can be used in the package portion utilizing the two important features of the invention described above. An example of such a package is shown in Figure 17, in which a pouch (140) of the type described in detail above is attached to cardboard (142). The sachets are attached to the cardboard support using a heat resistant adhesive, such as the adhesive used in the sachet seams. This type of package having a package portion made of a relatively rigid material such as cardboard has certain advantages. This type of packaging is generally suitable for fragile foods such as frozen pastries, which require more protection than can be provided by flexible packaging. This type of packaging is relatively self-supporting and is also suitable if no auxiliary outer packaging of any kind is used to transport the product to market. The first modification of the package form described above is
It is shown in Figure 8. In this variant, about half of the package is made of flexible laminate material (150) with a microwave-interactive layer.
The remaining half is made of a relatively rigid material such as cardboard (152), the flexible material being formed into a curved shape and seamed to the rigid material; It forms a closed space for storing food. As with all other packaging forms of the present invention, the area covered by the microwave interaction layer is larger than the total area of the food product on the flexible packaging portion and the area that is in mutual contact with the food product on the flexible packaging portion. The volume within the package for containing the food during wave cooking is greater than the maximum volume of the food at all points during cooking.

As will be appreciated, the containers or sachets of the present invention may be provided with an outer cardboard sleeve in the form of a generally rectangular parallel tube for additional packaging. FIG. 19 shows the pouch thus placed within the cardboard sleeve (160).

In some cases, a package is required that shields a portion of the food product from microwave energy so that it is not affected by the heating effect provided by the microwave interactive layer of the package of the present invention. If desired, such shielding may be provided within the package form according to the invention by providing aluminum foil within the package or on the outer surface, or by providing aluminum foil between the laminations of the stock used to form the package. can be included in

Figure 20 shows the aluminum foil shielding strip (170) and (
172) is attached to the inside of the pouch. Airflex 4 used to seal the seams of sachets
A strip of aluminum foil can be attached to the inner surface of the pouch using an adhesive of the type No. 21.

In practicing the invention, it is not necessary to include a microwave interactive layer within the material forming the overall shape of the package. For example, as shown in FIG. 21, a pouch may be constructed with a pouch-order structure (180) made of a material with no microwave interaction, and an insert (180) of the general composition shown in FIG.
182) can also be placed inside the pouch to obtain the desired heating effect.

The packaging form according to the invention allows food products to be packaged in a variety of ways.

First, a fully formed package, such as a sachet, can be supplied to a food packaging operation with only one end open for insertion of the food product. In such cases, the open end can be sealed after the food product is inserted, or the package can be placed in an outer carton for dispensing with one end left open. As a second method, blanks such as the unit blanks described in detail above can be supplied to a food packaging operation. When carrying out the second method, the formation of the blank into the final package form and the insertion of the food product therein can be carried out in a variety of ways, for example by placing the blank on the blank before sealing it into the package form. Food can be placed in the Third
As a method, roll stock of lightly metallized film and paper laminates, such as those described above, can be supplied to food packaging operations. Such rolled stock can be passed through a food packaging line to cut, shape and seal the stock to package food in a simple operation.

Roll particularly suitable for use in the food packaging line mentioned above
The form of the stock is shown in FIG. 22. This roll stock (190) has a suitable heat seal adhesive (192) printed on the inside surface of the stock in a pattern that corresponds to the sealing areas in the finished package. By applying adhesive to the stock in such a pattern, the presence of adhesive in areas of the package that come into contact with the food product can be prevented. The illustrated adhesive application pattern can also be printed onto stock by conventional methods such as gravure or flexography. A suitable printable heat seal adhesive for use on this type of roll stock is Roymar Incorporated (
It is commercially available as #42151 Waterborne Heat Seal Coating from Royal Inc., ).

FIG. 22 further shows a unit blank (194) cut from roll stock, a food product placed on one half (52) of the unit blank, folded along the center line (198), and finally an end edge (200). 20 shows a method of heat sealing a pouch along (202) and (204) to obtain a finished package containing a food product. Roll stock (19
0) is a laminate of paper and lightly metalized polyester film, as described above.

[Brief explanation of the drawing]

Fig. 1 is a plan view of a blank for making a pouch, Fig. 2 is a side view showing an intermediate step of forming the pouch of the present invention from the blank shown in Fig. 1, and Fig. 3 is a side view of the pouch when the pouch is completely closed. FIG. 4 is a cross-sectional view taken along line 4--4 in FIG. 1, showing the laminated structure of the blanks forming the pouch; FIG. 5 is a plan view of the package according to the present invention; Fig. 6 is a perspective view showing the pouch-shaped package according to the present invention in a completely sealed state; Fig. 7 shows one end of the pouch-shaped package. FIG. 8 is a perspective view of a pouch with both ends open; FIG. 9 is a perspective view of a pouch with ventilation holes; FIG. 10 is a perspective view of a pouch with a self-opening seal at one end. Figure 11 is a perspective view of a pouch with a ventilation hole covered by a self-opening closure; Figure 12 is a perspective view of a pouch with projecting parts at both ends that act as handles; Figure 13 is a perspective view of the pouch according to the invention. FIG. 14 is a cross-sectional view of a pouch-shaped package having two chambers according to the present invention; FIG. FIG. 15 is a perspective view of a pouch configured to allow a pouch containing food to be hung on a hanger inside a microwave oven, and FIG. 16 is a perspective view of a pouch configured to stand in a microwave oven at an intermediate position between horizontal and vertical positions. 17 is a sectional view of a pouch attached to a piece of rigid support material; FIG. 18 is a sectional view of a package according to the invention partially made of rigid support material; FIG. 19 Figure 20 is a perspective view of a sachet placed within a cardboard sleeve; Figure 20 is a perspective view of a sachet with aluminum foil shielding strips attached to the inside surface of the sachet; Figure 21 is a sachet constructed from microwave transparent material. FIG. 22 is a cross-sectional view of a package with a microwave-interactive portion provided as an insert placed within the package; FIG. FIG. 10: Unit blank (sachet), 12.14.16.18.30.34: Panel, 22.
24.26.28.32: Crease line, 30.34: Drop lid, 36: Transparent plastic, 40: PHT (polyethylene terephthalate) layer, 4
2: Microwave interaction layer, 44: Adhesive layer, 46 Two paper layers, 50: Microwave chamber, 52: Food, 54; Space above food, 60.80: Ventilation hole, 70: Seal, 82: Closed Piece, 90.92:
Auxiliary handle, 100.102.110.112: Chamber, 120: Hanging part, 152: Cardboard, IBO: Cardboard sleeve, +70.17
2 aluminum foil, 180: sachet-substructure, 182: insert, 190: roll stock, 192: heat seal adhesive 196: center line, 200.202.204: edge. FIG, 4 FIG, 5 FIG, II FIG, 13 FIG, 14 FIG, 15

Claims (1)

Claims: 1. A unit blank for forming a microwave food package, the blank comprising from one surface to the other (1) a PET layer, (2) a microwave interactive material layer, ( 3) a flexible generally planar laminate having an adhesive layer and (4) a paper layer, wherein said blank has an adhesive area and said blank is provided with a plurality of fold lines to enable folding. and thereby bonding the adhesive areas together to form a pouch suitable for placing food therein, the pouch being configured to be subject to microwave radiation to cook the food therein. A unit blank characterized by: 2. The blank of claim 1, wherein the adhesive area is on a surface of the PET layer that does not contact the microwave interactive material layer. 3. The blank of claim 2, wherein the blank is generally rectangular and the adhesive area is located at a peripheral portion of the blank. 4. A blank according to claim 3, wherein a portion of said blank is provided with a window-forming strip of transparent flexible plastic material. 5. A sachet for microwave cooking of food, said sachet being formed by a laminate, said laminate defining a unit blank as claimed in claim 1, said blank having a shape from one surface to the other (1). a PET layer, (2) a microwave-interactive material layer, (3) an adhesive layer, and (4) a paper layer, the blank having a folded crease line, the outer circumferential portions of which are adhered to each other; forming a flat container as a whole, said sachets having an inlet circumference which is not glued to one another, thereby forming an opening into which the food product can be inserted, said inlet circumference having an inlet circumference after the food has been inserted into the pouch; A microwave cooking sachet characterized by being configured to be airtight. 6. The pouch according to claim 5, wherein the pouch is generally rectangular. 7. The pouch of claim 6, wherein a portion of said pouch is provided with a strip of transparent flexible plastic material. 8. Food packages containing sachets and food inside the sachets,
The pouch is formed by a flexible unit laminate blank according to claim 1, and from one surface to the other surface:
(1) PET layer, (2) microwave interactive material layer, (
3) A food package comprising an adhesive layer and (4) a paper layer, wherein the volume of the food product is smaller than the internal volume of the sachet. 9. The food package of claim 8, comprising at least one strip of microwave opaque material overlapping a portion of the food product. 10. The food package of claim 8, including a cardboard reinforcement member attached to an outer surface of the package. 11. The blank of claim 1, wherein the surface area of the microwave interactive material layer is less than the surface area of the other components of the laminate.