MXPA06007113A - Microwave oven thawing tray for foodstuff - Google Patents

Abstract

This invention refers to the industrial area of manufacture of microwave oven accessories for thawing foodstuff in different compartments in response to the incidence of microwave ovens. Furthermore, this invention can also be applied in the industry of packages for frozen foodstuff. Advantages of the foregoing invention regarding trays of the prior art include allowing thawing of raw ingredients in the recopies without cooking them and thawing of cooked ingredients without changing their consistency;with a faster thawing operation;with ease of manufacture;whose cover can be easily detached from the rest of the container without having any kind of adhesive;that allows to easily hold sushi rolls with chopsticks;allowing microwave generated heat to go from one cavity to the next. This tray is characterized by comprising a lower base named tray and a thermosealed cover around the edges where they converge;both elements are made of materials with low microwave generated heat, specif ically materials made of polyester resins such as CPET (tray) and film (cover).

Description

CHAROLA FOR DEFROSTING FOOD PRODUCTS WITH MICROWAVES FIELD OF THE INVENTION The present invention is related to the industrial area of the manufacture of accessories for microwave ovens for defrosting food of different behaviors against the incidence of microwaves. On the other hand, this invention could also be applied in the packaging industry for frozen food products.

BACKGROUND OF THE INVENTION Very often, packaging is required to allow easy thawing of the contained products. There are several ways to defrost a product, one of them is to leave it outd until it is thawed, another is to put it in cold water for the same operation, it is also possible to thaw it by means of hot water or another source of heat in the that the temperature differential between the heat source and the product to be thawed allows for an important caloric exchange.

Currently, with the proliferation of microwave ovens and the advantages that these ovens have in terms of the efficiency of transformation of microwave energy into heat energy, a need has arisen to confer on the packages certain characteristics for an adequate behavior in a thawing process.

The behavior of the different materials before the bombardment of the microwaves, has generated a series of investigations to determine which are the most suitable materials for a package that will also serve for the defrosting of the products they contain.

On the other hand, if the materials that form the packages have been investigated to see their behavior before the bombardment of the microwaves, it is already known that, finally, the food products are heated thanks to the liquid water molecule increases its vibration by the effect of the microwave. This is what causes the food products to be heated by the microwave effect.

Without the effect of some susceptor you could never achieve a golden of any food, call it meat, bread or any other. Nor would it be feasible without these susceptors to reach the burst temperature of a corn to achieve the popcorn.

In the case of the defrosting problem, the differences in the characteristics of the components of any dish can make thawing in some components deficient and in others until it is cooked or overcooked.

And there are dishes in which in addition to understanding components of different water content, there are also dishes in which there are components that are cooked and components that must go raw.

Being components of the dish of different water contents, and being the molecule of water that is activated to heat, some components will be hard and leathery by the action of the microwave attack, others will be cooked and others will not reach to thaw.

For the defrosting of foods with the qualities mentioned above, there are a host of packages such as those described in patents US 6,844,536, US 5,861,184, US 4,794,008, and several other US patents.

There are also patents WO 03/016171, FR 02 05862, CA 2,417,450 and EP 1,279,605.

Some patents describe packages in which a defrosting is achieved without the package rupturing causing some damage in the oven or even in the people who handle the packaging for thawing.

Some packages solve the above by providing a cover with two types of materials, a central part being rigid and a peripheral part with a certain flexibility quality.

From an analysis of the different trays used to pack the frozen food product and designed likewise for microwave thawing the food product of cooked components and raw components, such as sushi, it can be perceived that in these it is presented at least in the part of the base of the packaging, a sheet metalized to reflect the microwaves.

These packages have the drawback of being complicated to manufacture the metal film and also without fully controlling the unfavorable effect of microwaves on raw products.

There are also packages with the characteristics of the materials that can cause important changes of the packaged food, or have a short shelf life, delaying the thawing operation.

OBJECTIVES OF THE INVENTION One of the objects of the invention is to provide a sushi-type frozen food package that allows the defrosting of the raw components of the recipe without cooking and defrosting the cooked without changing its consistency.

Another objective is to make possible a package with the above qualities that also makes the defrosting operation faster.

Still another objective, is to make possible a package whose cover can easily be separated from the rest of the packaging without contaminating the product with any type of adhesive.

Another objective is to make possible a tray with a design that allows to easily pick up the sushi roll with the Japanese sticks, allowing the passage of steam that could be generated during thawing, from one compartment to another.

Other objects and advantages of the present invention may be apparent from the study of the following description, where the basic qualities of our packaging are provided.

BRIEF DESCRIPTION OF THE INVENTION In short, the present invention consists of a tray made of special materials of low absorption of heat generated by microwaves, with rigid qualities that allow the handling for defrosting the ingredients of the sushi-type dish.

This tray contains cavities to accommodate the different foods to be defrosted. The shape of these cavities depends on the type of food. For example, in the case of sushi we have three types of sushi: Nigiri sushi, which is a ball of rice prepared (with vinegar, sugar, salt) with a thin slice of raw fish or vegetables on top; sushi aki, which is a roll of prepared rice, surrounded by a seaweed and stuffed with portions of raw fish or seafood and / or vegetables and the Guncan, which is a ball of prepared rice, surrounded by a seaweed and stuffed of any type of fish roe.

In addition to the shape due to the type of sushi itself, channels are included to communicate the heat generated by the microwaves, between the different cavities. In the compartments of the sushi roll (Maki sushi), there are vertical slots at opposite ends, where you can enter the Japanese sticks to catch the sushi rolls.

The packaging is complemented with a cover consisting of a film of plastic material also completely low absorption of heat generated by the microwaves, which causes them to penetrate balanced distributed between the cover and the bottom of the tray.

The connection of the cover with the tray is carried out by means of heat sealing in the areas where the upper contour of the tray and the cover coincide.

For this structure to work it is important to note that the product must have been subjected to a quick freeze to reduce the size of the frozen water glass, allowing the microwave to have a much larger contact surface area. This is the characteristic that frozen products normally have.

In order to achieve all the proposed objectives, the material must also be of a certain degree of rigidity. Semi-rigid at the base and flexible on the cover.

After multiple tests it was determined that the best material for its low absorption of heat generated by microwaves are polyester resins. Specifically, the material with optimum qualities is what is known in the market as CPET, crystallized polyethylene terephthalate thermoplastic. The Cpet is extruded into sheets that are then subjected to a process by thermoforming at high temperatures which is in the form of a tray with its properties of high temperature resistance, providing an undoubted advantage to avoid being subjected to to the bombing of the microwaves absorb a lot of heat which would cause the sushi to suffer burn or cooking seriously damaging the thawing process.

The film (cover), in one of its modalities, is a co-extrusion of the polyester resin whose chemical composition is polyethylene terephthalate which, when in contact with microwaves and during the short period of time we use, does not absorb quantities of heat that damage the integrity of the sushi by burning and cooking it. As already mentioned, the union between the tray and the cover is carried out by means of heat sealing, not using any adhesive that could later be detached and become part of the food contaminating it.

Another type of film is that which consists of a film whose main layer is bi-oriented polyester but contains several layers laminated to the same polyester which are: * layers laminated to polyester: * * evoh: * alcohol ethylene vinyl * polyamide: (nylon) * * polyolefin: * ethylene co-polymer The simple fact that the package or the defrosting tray with the cover are of low absorption material of the heat generated by the microwaves, means an important adv in the state of the art, However, more specifically, the contribution to the state of the technique that the best materials are polyester resins and especially CPE means a more specific adv. It was surprisingly found that this type of material not only achieved the homogeneous thawing of the different ingredients, but also reduced the time of the thawing process.

In order to better understand the characteristics of the invention, the following description, as an integral part thereof, is attached to the drawings, which are illustrative rather than limiting, which are described below.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 shows a conventional perspective view of the tray that includes two types of sushi; Figure 2 illustrates a conventional perspective view of the tray that includes only Maki sushi.

For a better understanding of the invention, a detailed description will be made of some of the modalities thereof, shown in the drawings, which for purposes of illustration but not limitation, are annexed to the present description.

DETAILED DESCRIPTION OF THE INVENTION The characteristic details of this novel tray for defrosting food will be shown with the detailed description of the modality illustrated in the attached drawings, indicating the same parts with the same reference signs to indicate the same.

Figure 1 shows a conventional perspective view of the tray that includes two types of sushi; in the caidades 3 where the Maki sushi is placed and the cavity 5 where the other type of sushi can be deposited.

In the cavities 3 where the Maki sushi is placed, there are vertical slots 1 where the Japanese sticks are introduced to take the sushi roll. In the case of the other cavities 5, vertical slots 4 are also available to catch the other types of sushi.

For the passage of the heat generated by the microwaves in each of the cavities, there are passages in the cavities of Maki 2 and in the cases of the other types of sushi, passages 6.

In another aspect of our invention, in a more detailed manner, our invention consists of a package formed by a base, also called tray, and a cover consisting of a film of plastic material, both with low absorption of heat generated by the microwave, which causes them to penetrate bald distributed between the cover and the bottom of the tray.

The film is selected for its low absorption of heat, and is what acts as a lid, and is thermally sealed to the contour of the tray prior air extraction. The advantage of this film is that the consumer opens it easy, besides that it does not contain any adhesive that can contaminate food.

The tray is made of Cpet, which is extruded into sheets that are then subjected to a process by thermoforming at high temperatures which is in the form of tray with its properties of high temperature resistance providing an undoubted advantage for avoid being subjected to microwave bombardment absorb a large amount of heat which would cause the sushi to suffer burn or cooking seriously damaging the thawing process.

The film (cover) is a co-extrusion of the polyester resin whose chemical composition is polyethylene terephthalate which, when in contact with microwaves and during the short period of time we use, does not absorb quantities of heat that damage the integrity of the sushi burning and cooking. It is a biaxially oriented polyester film with an amorphous layer of thermally sealed polyester, with an excellent barrier to oxygen, carbon dioxide and water, High resistance to high and low temperatures, and do not interact with microwave radiation with this polyester film.

The invention comprises another embodiment of the film consisting of a film having as its main layer bi-oriented polyester but also containing several layers laminated to the same polyester which are: * evoh: * alcohol ethylene vinyl * po 1 iamide: (nylon) * * Polyolefin: * ethylene co-polymer Then, it was determined that the two materials with better performance to achieve defrosting in a microwave oven, for sushi-type foods, are the CPET (tray) and the polyester film (cover), with more or fewer layers of the same or other materials.

The tray made of CPET is thicker than the cover, and has a heat treatment that was applied at the time of thermoforming the cavities where the components of the dish will be located, for example, in sushi, precooked rice, raw fish and vegetables too raw.

In one of the modalities, the tray can understand is its material a black pigment to avoid the interaction of ultraviolet light with the food.

Our Cpet is extruded with double layer structure of the same Cpet for the purpose of increasing its rigidity and resistance at high temperature (when subjected to microwave to thaw) and increases its resistance to impact when subjected to very low temperatures (less ° C), this one, temperature of preservation of the sushi in the tray.

The invention has been sufficiently described so that a person with average skill in the art can reproduce and obtain the results that we mentioned in the present invention. However, any person skilled in the art who is competent in the present invention may be able to make modifications not described in the present application, however, if for the application of these modifications in a certain structure or in the manufacturing process thereof, the subject matter claimed in the following claims is required, said structures should be understood within the scope of the invention.

Claims (5)

R E I V I N D I C A C I O N S Having sufficiently described the invention, it is considered as a novelty and therefore it is claimed as property what is expressed and contained in the following claim clauses.

1. Tray for the thawing of food products with microwaves, characterized by comprising a lower base called a tray and a thermo-sealed cover in the periphery where these coincide, both elements being resins of low heat absorption generated by microwaves, specifically selected resins among the set of the various polyesters and particularly that known in the state of the art as CPET.

2. Tray for the thawing of food products with microwaves, as claimed in the previous claim, characterized in that the material commonly known as CPET (crystallized polyethylene terephthalate).

3. Tray for thawing food products with microwaves, as claimed in claim 1 or 2, characterized in that the film of the polyester cover is a biaxially oriented polyester film with an amorphous thermally sealed polyester layer, with excellent barrier to oxygen, carbon dioxide and water, high resistance to high and low temperatures, and The microwave radiation does not interact with this polyester film.

4. Tray for thawing food products with microwaves, as claimed in the previous claim, characterized in that the main layer is bleached polyester and other layers laminated to it: * evoh: * alcohol ethylene vinyl * polyamide: (nylon ) * * polyolefin: * ethylene co-polymer

5. Tray for the thawing of food products with microwaves, as claimed in claim 1 to 4, characterized in that the cavities where the food go have two vertical slots to introduce the Japanese sticks and to be able to easily catch the sushi and communication channels with the neighboring cavities to allow the communication of heat between them. SUMMARIZES The present invention is related to the industrial area of the manufacture of accessories for microwave ovens for defrosting food of different behaviors against the incidence of microwaves. On the other hand, this invention could also be applied in the packaging industry for frozen food products. The advantages of the present invention with respect to the trays of the state of the art, are to allow thawing of the raw components of the recipe without cooking them and thawing the cooked ones without changing their consistency; with a faster defrosting operation; easy to manufacture; whose cover can easily be separated from the rest of the packaging without contaminating the product with any type of adhesive; that allows to easily catch the sushi roll with the Japanese sticks, allowing the passage of the heat that could be generated during the exposure to the microwaves during thawing, from one compartment to another. The tray is characterized by comprising a lower base called tray itself and a thermo-sealed cover in the periphery where these coincide, both being a material of low absorption of heat generated by microwaves, specifically of materials made of polyester resin as This is the case of the CPET (tray) and the film (cover).