JP6522714B2 - Container for microwave heating food - Google Patents

Description

  BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to a microwave oven-heated food container, and more particularly to a container that enables efficient exhaust of water vapor from a lid.

  When cooking cooked food at a retail store such as a convenience store or the like after cooking or bringing it home after cooking, the container for packaging these foods has a container body portion and a lid portion fitted to the opening thereof It consists of a combination. In particular, since it is a single-use container used for one-time use such as storage, display, and sale of food, the lid fitting structure is simplified as much as possible. Therefore, currently, molded articles of synthetic resin sheets are the mainstream of containers.

  A microwave oven (microwave irradiation) is usually used for cooking and reheating food. Therefore, the food container is provided after being put in a microwave and heated as it is. Focusing on foods actually sold, there are foods with a large amount of water such as soups, and foods with a small amount of water per weight such as stir-fry, etc. The types of foods are quite versatile. The problem here is that water vapor is generated from the food in the container when the food is cooked by the microwave oven.

  In the lid fitting container, if the fitting between the container body and the lid is loosened, exhaust of the internally generated water vapor is easy. However, when the fitting on the lid side is loose, there is a concern that foreign matter may be mixed due to problems such as the lid being easily detached at an intermediate stage of manufacturing, shipping and display. For this reason, the reputation from the food purchaser is not desirable. Then, the cover which formed the hole part for exhausting the water vapor | steam generated internally to the container exterior is proposed (refer patent document 1, 2 grade | etc.,). According to the lid of the container represented by patent documents 1 and 2, the tongue-like opening by U-shaped or V-shaped cut is formed in the lid. Water vapor is released to the outside of the container through this tongue-shaped opening.

  The exhaust efficiency of the tongue-shaped opening with a U-shaped or V-shaped cut is good. However, the fact that the exhaust of water vapor is good also increases the risk of foreign matter intrusion from the tongue-like opening. Therefore, in this case, a sealing tape for closing the tongue-like opening may be attached. Furthermore, a film member for covering the tongue-like opening may be separately covered if necessary. For example, when a film member is placed, a wall surrounding the tongue-shaped opening is provided on the lid side, and a gap is formed around the tongue-shaped opening. And a passage of water vapor is formed also in this wall part, and the structure was complicated. Moreover, when the tongue piece by a cut is broken and it falls in the inside of a container, the problem in which the foreign material itself is mixed is also included.

  As described above, containers using an existing structure for exhausting water vapor require materials other than those necessary only for food packaging, which inevitably raises costs. In addition, the shape of the tongue-shaped opening by cutting is uniform, and there are many restrictions on the peripheral structure.

JP, 2012-50672, A Utility model registration No. 3056026

  From a series of circumstances, the inventor has been searching for a new exhaust structure to replace water vapor exhaust using a tongue-shaped opening with a U-shaped or V-shaped incision. Among them, it has been found that a structure in which a plurality of fine holes are provided in the lid of the container is effective. And since it was a fine hole, it turned out that the tolerance to breakage or foreign material mixing is also good.

  The present invention has been made in view of the above-mentioned point, and proposed a new exhaust structure replacing the water vapor exhaust using a tongue-shaped opening with a conventional U-shaped or V-shaped incision, It is possible to provide a container for microwave oven heating food which enables efficient steam exhaust, simultaneously realizes improvement in sealing performance and suppression of contamination, and also has few restrictions on the shape of the lid and is also advantageous in reducing material cost. .

That is, the invention according to claim 1 is a lid fitting container including a container main body for containing food for microwave oven heating, and a lid portion which fits with the opening of the container main body, wherein is Futamen on the peripheral wall portion so as to surround the concave portion and the concave portion is formed in the lid surface of the lid portion, the concave portion, the water vapor generated from the food contained in the container main body portion to the outside exhaust hole group comprising a plurality of exhaust pores exhaust, be formed without providing a coating or foreskin members of those exhaust pore group, together with the exhaust pores are bored by laser irradiation, wherein The diameter of the exhaust pore is 0.15 to 0.59 mm, the number of the exhaust pores is 8 to 1000, and the total opening area of the exhaust pores in the exhaust hole group is 0.25 to 0.5 that it is a 100mm ² According to microwave heating food container according to symptoms.

According to the container for heating microwave oven food according to the invention of claim 1, a lid comprising: a container main body portion for containing food for microwave oven heating; and a lid portion to be fitted with the opening portion of the container main body portion A fitting container, wherein a lid surface portion of the lid portion is provided with a concave portion and a lid surface upper peripheral wall portion so as to surround the concave portion, and the concave portion is a food accommodated in the container main portion puncture exhaust hole group comprising a plurality of exhaust pores for exhausting the steam generated externally, be formed without providing a member covering or foreskin an equivalent exhaust pore group, said exhaust pores by laser beam irradiation from The diameter of the exhaust pore is 0.15 to 0.59 mm, the number of the exhaust pore is 8 to 1000, and the opening area of the exhaust pore in the exhaust hole group The total of is not 0.25 Than it is 100 mm ^2, instead of exhaust of water vapor using a tongue-shaped opening by U-shaped or V-shaped slit provided in the lid of the conventional lid fitting container, good steam exhaust At the same time, the sealing performance can be improved, and the contamination can be suppressed, and at the same time , the restriction on the shape of the lid can be reduced, and the material cost can be reduced. In particular, according to the invention of claim 1, as described above, the exhaust hole group consisting of a plurality of exhaust holes is formed without providing a member for covering or exfoliating the exhaust hole group, The diameter of the hole is defined as 0.15 to 0.59 mm, the number of the exhaust pores is 8 to 1000, and the total opening area of the exhaust pores in the exhaust hole group is 0.25 to 100 mm Therefore, the present invention can cope with the packaging of many foods distributed in the real market, and forms an exhaust pore group instead of the conventional water vapor exhaust structure as shown in the embodiments described later. By itself, it is possible to provide a good water vapor exhaust as well as a foreign matter mixing suppression effect. Furthermore, according to the invention of claim 1, since the exhaust gas holes are formed by laser beam irradiation, the exhaust gas holes can be easily and quickly formed in the lid surface.

It is a whole perspective view of the isolation | separation state of the container for microwave oven heating which concerns on one Embodiment of this invention. It is a 1st fragmentary sectional view of the container for microwave oven heating. It is a 2nd fragmentary sectional view of the container for microwave oven heating. It is a top view of the top view figure of an exhaust hole group. It is the 1st photograph at the time of putting food in the container for microwave oven heating food. It is the 2nd photograph at the time of putting food in the container for microwave oven heating food.

  The food container 1 according to one embodiment of the present invention is a combination of the container body 100 and the lid 10 fitted with the opening 101 of the container body 100, as shown in the overall perspective view in the separated state of FIG. A lid fitting container comprising In particular, the food is contained in the container interior 103 of the container body 100, and is heated or heated by microwave irradiation of the microwave (heat cooking) while the lid 10 is covered. Therefore, the food container 1 is a "microwave heated food container".

  In the lid surface portion 11 of the lid 10, an exhaust hole group 20 including a plurality of exhaust pores 21 is formed. During heating or heating by the microwave, the water vapor generated from the food C (see FIG. 3) contained in the container body 100 is exhausted to the outside of the food container 1 through the exhaust pores 21. In the lid portion 10 of the present invention, a concave portion 30 appropriately dug down from the lid surface portion 11 is formed on the whole or a part of the lid surface portion 11. An exhaust hole group 20 is formed in the concave portion 30. Further, a lid surface upper peripheral wall portion 35 is formed so as to surround the concave portion 30.

  By provision of the concave portion 30, when the water vapor jetted from the exhaust pore 21 is liquefied and turned into water droplets, the water droplets stay in the concave portion 30 and do not spread in the lid surface portion 11. As a result, the wet portion of the lid surface portion 11 can be reduced. The lid surface upper peripheral wall portion 35 is an enclosure and is provided for the purpose of preventing the leakage of water droplets.

  The fitting of the illustrated container body 100 and the lid 10 is referred to as an inner fitting, in which the periphery of the lid 10 is fitted into the opening 101 of the container body 100. Around the lid portion 10, a peripheral wall portion 15 having a U-shaped cross section that fits inside the opening portion 101 of the container main body portion 100 is provided. In the form of the inner fitting, the close contact between the container body 100 and the lid 10 is strong. Therefore, it becomes difficult to detach lid part 10 easily. Of course, the fitting form may be an outside fitting other than the inside fitting shown. For example, the edge of the lid portion covers the opening of the container body from the outside.

  In the container body portion 100, the opening step portion 107 is provided in the opening portion 101, and the peripheral wall portion 15 of the lid portion 10 can be received and fitted inside. The container body 100 is formed of an opening 101, a body 104, and a bottom 105 from the upper side, and becomes a pot-shaped or bowl-shaped container having an inner volume sufficiently corresponding to the amount of food. The cross-sectional shapes of the container body 100 and the lid 10 are appropriate and are circular in the drawing. It is also possible to have a cross-sectional shape such as a polygon or an oval.

  Food containers 1 (combination of container body 100 and lid 10) are mainly sold at convenience stores, supermarkets, department stores, restaurants, delicatessen specialty stores (delicatessen), coffee shops, shops such as service areas, etc. The container is a lid fitting container for simply storing and packaging a food including various beverages such as lunch, sugar beet, noodle dishes, soup dishes, and further coffee, cocoa, black tea, green tea, herbal tea and the like. The mainly envisaged application is a single-use container (disposable container) used for one-time use called one-way or disposable. By using a single-use container, it is convenient for food hygiene management.

  The food container 1 is mainly intended for use as a single-use container. Therefore, the lid portion 10 is formed of a synthetic resin sheet (plastic resin sheet) which can be mass-produced inexpensively and simply. Specifically, the lid 10 is a sheet (synthetic resin sheet) of a thermoplastic resin such as polyethylene, polypropylene, polystyrene, polyethylene terephthalate (PET resin) or the like, and further, a biodegradable thermoplastic resin such as polylactic acid. It is a sheet. Although the thickness of the synthetic resin sheet is appropriate, it is about 1 mm or less in thickness, and usually 200 to 700 μm in thickness. Then, the synthetic resin sheet is molded by vacuum molding. Considering mass productivity at the time of molding when using a synthetic resin sheet as a raw material, processing accuracy and the like, vacuum molding is simple and optimum.

  In the combination of the container body portion 100 and the lid portion 10, the raw material resin of the synthetic resin sheet may be the same type or a different type. In particular, since the food container 1 copes with heating by a microwave oven, the container body side may be made of expanded styrene or paper in consideration of heat conduction. The kind of resin to be used is suitably selected by the use, the contents, and the package object.

  The fitting portion of the container body 100 and the lid 10 in the illustrated embodiment and the exhaust hole group 20 (exhaust pores 21) in the illustrated embodiment will be described using the partial cross-sectional views of FIGS. 2 and 3. FIG. 2 shows the lid in the separated state, and FIG. 3 shows the lid in the fitted state (fitting or joining). The peripheral wall 15 of the lid 10 with a U-shaped cross-sectional view is formed of the lid contact wall 16, the circumferential groove bottom 17, and the inner side wall 18. A flange portion 19 is provided on the outer edge of the lid close contact wall portion 16. In the opening 101 of the container body 100 corresponding to this, the outer flange portion 109, the opening peripheral wall portion 106, and the opening step portion 107 are formed at the lower end thereof.

  Furthermore, as understood from the state of FIG. 3, when the peripheral wall 15 of the lid 10 is fitted into the opening 101 of the container body 100, the lid adhesion wall 16 is in close contact with the opening peripheral wall 106 ( Wear it. Thus, the airtightness of the inside of the food container 1 is enhanced. However, the escape route of the water vapor generated from the food C accommodated in the inside of the container 1 for food by that amount is lost. Therefore, the internally generated water vapor Vp is released from the exhaust pores 21 formed in the lid surface portion 11 of the lid portion 10 to the outside of the food container 1. In this manner, the food container 1 is abnormally expanded, and the problem of deformation or unnatural opening of the lid is avoided.

  In the case of the individual exhaust pores 21 constituting the exhaust hole group 20 in the lid surface portion 11 of the lid portion 10, the processing method for the penetration thereof is appropriate, and is, for example, a needle stick or a drill. However, in the case of these physical processing methods, in addition to requiring much time, there is a point that sufficient processing accuracy can not be obtained. In addition, in the case of hole formation, the problem of the generation of fine powder can not be removed, and it takes time and effort for subsequent cleaning. Therefore, irradiation of a laser beam is used to easily and quickly form an exhaust pore in the lid surface.

  The laser beam is not particularly limited as long as the processing output can be obtained, and various lasers such as a carbon dioxide gas laser, a YAG laser, a semiconductor laser, and an argon laser are used. As described above, when the material of the lid portion is formed of a sheet of synthetic resin, the exhaust pores are formed easily and in a short time by laser beam irradiation.

  Here, the index defining the exhaust pore 21 constituting the exhaust hole group 20 will be described in more detail. As a first index, the diameter of each exhaust pore 21 is at least 0.59 mm or less. Furthermore, the diameter of the exhaust pore 21 is preferably in the range of 0.15 to 0.5 mm, and particularly preferably in the range of 0.19 to 0.35 mm.

As a second index, the required number of exhaust pores 21 constituting the exhaust hole group 20 is in the range of approximately 8 to 1000, preferably 10 to 990, in consideration of the results of the examples described later. Range . The diameter of the exhaust pore 21 is fine as described above. Therefore, since it is effective for exhausting internally generated water vapor, it is necessary to secure an appropriate number of exhaust pores.

  The number of exhaust pores also depends on the size of the diameter of the exhaust pores themselves, as well as the type of food which is the content. Therefore, if the number of exhaust pores is too small, sufficient exhaust of water vapor can not be realized, and the pressure of the generated water vapor may cause the fitting of the lid to open unnaturally. The upper limit of the number of exhaust pores is defined in consideration of the design shape of the lid surface of the lid and the diameter of the exhaust pores. In addition, when the diameter of the exhaust pore is small, the number of exhaust pores must be increased correspondingly. Therefore, the upper limit of the number of exhaust pores is approximately 1,000.

As a third index, the total of the open areas of the exhaust hole group 20, that is, the total of the open areas of all the exhaust pores 21 on the lid surface portion 11 is in the range of 0.15 to 100 mm ² . The total minimum amount of open area is defined by the product of the minimum diameter and the minimum number of exhaust pores. However, the area amount is a value for food with a very small amount of generated water vapor. Therefore, in consideration of the type of compatible food, reasonable lower limit 0.25 mm ² of the total open area, preferably 0.28 mm ^2.

For example, in the case of noodle cooking, the volume of the container for food also increases because the amount of soup in addition to the noodles is large. If it does so, the heating time by a microwave oven will become long, and the amount of water vapor | steam which generate | occur | produces in the whole container will also increase relatively. In this case, it is necessary to increase the total open area in order to promote the good exhaust of water vapor from the exhaust pores. However, even if the number of exhaust pores is increased beyond the required capacity, there is a concern that the time and effort for drilling may increase and the strength of the lid may decrease. Therefore, 100 mm ² as the upper limit of the total open area, 80 mm ² are derived as a more preferable upper limit. Since the total of the open area of the exhaust hole group is in the above-mentioned range, the microwave oven heated food container (lid part) can cope with many foods distributed in the market.

  Each top view of FIG. 4 shows the other example of an exhaust hole group formed in the cover part 10 (cover surface part 11). The exhaust hole group 20 a in FIG. 4A is formed in a rectangular shape by forming the exhaust pores 21. The illustrated concave portion 30a is rectangular. The exhaust hole group 20b of (b) is formed in a substantially circular or rhombic shape by drilling the exhaust pores 21. The illustrated concave portion 30b is circular. The exhaust hole group 20c of (c) is formed in a shape imitating the letter “A” of the alphabet by the formation of the exhaust holes 21. The illustrated concave portion 30c has a rectangular shape. That is, the exhaust hole group is configured as a plane figure. Planar figures include not only figures but also letters and symbols.

  The shape of the plan figure of the exhaust hole group can be freely designed by setting at the time of laser beam irradiation. For this reason, restrictions such as a U-shape or a V-shape such as a tongue-shaped opening by a conventional cut are eliminated. By the plan figure of the exhaust hole group formed by drilling the exhaust hole, various information such as the manufacturer's and seller's trademarks, marks, logos and even the date of manufacture can be displayed through the exhaust hole group .

  As described above, in consideration of the diameter of the exhaust pore in the container for food (the container for microwave oven heated food) of the present invention, since it is extremely fine, it is possible to effectively suppress the entry of foreign substances such as insects. Therefore, in the food container of the present invention, it is possible to omit a member such as a film covering or excreting a hole responsible for the exhaust of the lid found in a conventional container. Therefore, the food container of the present invention can contribute to the reduction of the cost of packaging materials without the need for time-consuming operations such as microwave oven heating or opening at the time of heating. In particular, the food container of the present invention is provided with the sum of the open areas of the exhaust holes, as well as the definition of the number of exhaust holes. Thus, the food container of the present invention is an extremely convenient packaging material that can cope with the amount of water vapor generated from many types of food. Furthermore, since various exhaust hole groups can be formed by the arrangement of the exhaust pores, not only the restriction on the shape design of the lid portion is reduced but also the degree of freedom in the shape of the exhaust hole group itself is enhanced.

[Preparation of a container for microwave oven heating food-1]
The container for microwave oven heating food was an article consisting of a combination of a container body and a lid. The said "preparation-1" assumed packaging of food with a large amount. For the lid portion, a sheet material of heat resistant biaxially oriented polystyrene (heat resistant OPS) resin was used. This was processed into a disk-like lid by vacuum forming. The maximum diameter of the lid was about 175 mm, and the maximum diameter of the lid was about 135 mm. The material thickness of the lid portion was 0.3 mm. A heat-resistant expanded polystyrene sheet material (polypropylene film adherend) was used for the container body. The resultant was vacuum-formed into a bowl-like (pot-like or bowl-like) container body with a circular cross-section. The opening diameter (inner diameter) of the container body was about 160 mm and the depth was 70 mm, and the internal volume of the container body (food-containable volume) was about 800 mL.

[Formation of exhaust holes-1]
At the time of formation of the exhaust hole group, exhaust pores were drilled in the central portion of the lid obtained by the above-mentioned molding, using a known carbon dioxide gas laser irradiation device generally used in the resin processing field. At this time, while changing the conditions of the irradiation device, five types of diameter (diameter) of individual exhaust pores were set to "0.19, 0.26, 0.35, 0.50, and 0.59 mm" . Further, the number of exhaust pores to be drilled according to the diameter of the exhaust pores is also 11 types of "60, 100, 150, 200, 300, 400, 500, 600, 700, 800, and 990". That is, by combining the diameter of the exhaust pore and the number of the exhaust pores, a lid of the prototype of a combination of 55 types in total was manufactured.

[Microwave heating test of food-1]
The types of food actually sold are quite diverse. Therefore, the inventor selects three types of food having different water content as representatives (food examples 1 to 3 below), accommodates each in the container main body, and appropriately fits the lid (each prototype) (See the picture in Figure 5). And it used for the heating test using the high output type microwave oven introduced into the convenience store etc. An example where the lid does not come off from the container body even when the lid is subjected to the pressure of the internally generated water vapor due to food when heating in a microwave oven is regarded as a "good product"; It is judged that "the defective product".

The results of the presence or absence of the lid portion removal are "Table 1", "Table 2", and "Table 3". In each table, the horizontal axis is a division of the diameter (mm) of the exhaust pore, and the vertical axis is a division of the total number (number) of exhaust pores. The intersecting value of both indices is the sum of the aperture area (mm ² ). Specifically explaining using Table 1, the diameter of the exhaust pore is 0.26 mm from the horizontal axis, and the number of exhaust pores is 700 from the vertical axis. First, the open area of one exhaust pore is 0.053 mm ² . The total area is 37.1 mm ² (rounded to the second decimal place) when 700 exhaust pores are added. That is, the frame at the intersection point of both axes is the notation of the total area.

  In each table, a trial production example in which a numerical value exists in the frame of the intersection position of both indexes is an example actually tried. The frame with only a thick solid line is a "good product" without the lid part coming off. The frame of the numerical value with the diagonal line is a "defective product" with the lid part coming off. In addition, the blank part in each table | surface is the area | region which abbreviate | omitted the test from the tendency of good / defect.

Food Example 1
Food Example 1 was "pork soup udon", and the total weight of noodles, soup and ingredients was about 580 g. Food Example 1 was charged in the same amount into the container main body by molding as described above, and the lids of eight trial manufacture examples in Table 1 were fitted and fitted. The microwave oven was set to 1500 W power for 2 minutes and 15 seconds. The result is shown in Table 1.

Food Example 2
The food example 2 was "curry rice", and the total weight of rice and roux was about 470 g. Food Example 2 was charged in the same amount into the container main body by molding as described above, and lids of nine types of trial manufacture examples in Table 2 were fitted and fitted. The microwave oven was set to a heating condition of 1500 W for 1 minute and 20 seconds. The results are shown in Table 2.

Food Example 3
The food example 3 is "pasta (carbonara · spaghetti with light eggplant)", and the total weight of the pasta, the sauce, and the ingredients was about 370 g. The same amount of each of the food example 3 was put into the container main body by molding as described above, and the lids of nine kinds of trial manufacture examples of Table 3 were fitted and fitted. The microwave oven was set to an output of 1500 W and heating conditions of 1 minute and 10 seconds. The pass / fail results are shown in Table 3.

FIG. 5 is a part of a photograph of the food when food examples 1, 2 and 3 are packed in a container for heating a microwave oven and heated under the above conditions. The upper row is an example of food example 1 (pork soup udon): an exhaust pore diameter of 0.35 mm, 500 exhaust pores, and an open area of 48.1 mm ² in total. The middle row of the food example 2 (curry rice): the exhaust pore diameter is 0.19 mm, the number of exhaust pores is 600, and the opening area is 17.0 mm ² in total. The lower part is a food example 3 (pasta / spaghetti): an exhaust pore diameter of 0.26 mm, an exhaust pore number of 300, and an opening area of 15.9 mm ² in total. Each stage, the left side is before microwave oven heating, and the right side is a photograph after microwave oven heating.

[Consideration of microwave oven heating test 1]
In the case of the pork broth udon of the food example 1, the amount of steam generated at the time of microwave heating increased because the amount of the soup was large. As can be understood from the tendency of Table 1, it is necessary to increase the total opening area by increasing the number of exhaust pores if the diameter of the exhaust pores becomes smaller. Also, the opposite is true. Next, looking at the results of curry and rice of food example 2 (Table 2) and the results of pasta of food example 3 (Table 3), it can be judged that the water content is not as large as that of food example 1 The amount of water vapor decreased relatively. Therefore, it was found that even the area which becomes defective in the open area of the food example 1 disclosed in Table 1 can be included in the non-defective product. That is, it was convinced that the sum of the diameter of the exhaust pore, the number of the exhaust pore, and the open area could be flexibly set according to the kind of food to be packaged.

[Preparation of container for microwave oven heating food-2]
Based on the above-mentioned "Consideration of microwave oven heating test 1", the application to a smaller amount of food packaging is assumed in "Production-2". Moreover, from the tendency which became clear, the conditions which narrowed down the object in the range which made the diameter of the exhaust pore small, and reduced the number of exhaust pores were also added.

  For the lid portion in “Preparation-2”, a sheet material of heat-resistant biaxially oriented polystyrene (heat-resistant OPS) resin similar to that of “Preparation-1” was used. This was processed into a disk-like lid by vacuum forming. The maximum diameter of the lid was about 111 mm, and the maximum diameter of the lid was about 75 mm. The thickness of the material of the lid was 0.25 mm. A polypropylene sheet material was used for the container body. This was processed by vacuum forming into a bowl-like (pot-like or cup-like) container body with a circular cross section. The opening diameter (inner diameter) of the container body was about 100 mm and the depth was 90 mm, and the internal volume of the container body (food-containable volume) was about 400 mL.

[Formation of exhaust holes-2]
At the time of formation of the exhaust hole group, an exhaust pore was bored in the central portion of the lid obtained by the above-mentioned molding, using the same irradiation apparatus as described above. At this time, two types were prepared in which the diameter (diameter) of each exhaust pore was "0.19 and 0.26 mm". Further, the number of exhaust pores to be drilled according to the diameter of the exhaust pores was also set to 10 types of "5, 10, 20, 25, 40, 70, 100, 150, 200, 300". In this way, a lid of a trial example of a total of 20 types of combinations was manufactured.

[Microwave heating test of food-2]
Next, the inventor selects three types of food having different water content and sold in smaller volumes than the above-mentioned "Test-1", as a representative (food examples 4 to 6 below), and stores them in the container main body, The lid part (each trial production example) was fitted properly (see the photograph in FIG. 7). Then, it was subjected to a heating test using the same high-power type microwave oven as described above. Also in "Test-2", during microwave heating, an example in which the lid does not come off from the container body even if it receives the pressure of internally generated water vapor caused by food is considered as "good product" and the lid is detached. An example (including unnatural uplifting) that was lost was judged as a "defective product". The result of the presence or absence of the detachment | deletion of the cover part of "test-2" is "Table 4", "Table 5", and "Table 6". The method of description in each table is the same as that of the above-mentioned Table 1 grade. However, the third decimal place was rounded off.

Food Example 4
Food Example 4 was "Dan-Da soup", and the total weight of the soup and ingredients was about 290 g. The same amount of each of the food example 4 was put into the container main body by molding of "preparation-2", and the lids of ten types of trial manufacture examples of Table 4 were covered and fitted. The microwave oven was set to an output of 1500 W and heating conditions of 1 minute and 10 seconds. The results are shown in Table 4.

Food Example 5
The food example 5 was "fried tofu", and the total weight of tofu and soy sauce was about 200 g. Similarly, the same amount of food example 5 was put into the container main body portion, and the lid portions of 10 types of trial manufacture examples of Table 5 were covered and fitted. The microwave oven was set to a heating condition of 1500 W for 40 seconds. The results are shown in Table 5.

Food Example 6
Food Example 6 was a "yakitori", and the total weight of chicken and sauce was about 140 g. Similarly, the same amount of each of the food example 6 was put into the container main body portion, and the lid portions of 15 kinds of trial manufacture examples of Table 6 were covered and fitted. The microwave oven was set to an output of 1500 W and a heating condition of 25 seconds. The pass / fail results are shown in Table 6. In addition, about the foodstuff example 6, the same experiment was also tried by preparing the cover part which does not form an exhaust_gas | exhaustion pore at all. As a result, when 18 seconds passed from the start of heating, the fitting of the lid portion was released.

FIG. 6 is a part of a photograph of the food items 4, 5 and 6 packed in a container for heating a microwave oven and heated under the above conditions. The upper row is food example 4 (Dan-Da soup): an exhaust pore diameter of 0.26 mm, an exhaust pore number of 150, and an opening area of 7.96 mm ² in total. The middle row of the food example 5 (fried tofu): the exhaust pore diameter is 0.19 mm, the number of exhaust pores is 100, and the total area of the openings is 2.83 mm ² . The lower part of the food example 6 (baked chicken): an exhaust pore diameter of 0.19 mm, an exhaust pore number of 40, and an opening area of 1.13 mm ² in total. In each stage, the left side is before microwave oven heating, and the right side is after microwave oven heating.

[Consideration of microwave oven heating test-2]
In the case of the food soup of food example 4, the amount of water vapor generated at the time of microwave heating increased because of the relation of the amount of water to the food. However, since the capacity was small and microwave heating was also shortened, even if the number of exhaust pores is reduced by the diameter of the small exhaust pores compared with Food Example 1 in Table 1 described above, it is sufficient. It was possible to realize an efficient steam exhaust. Next, looking at the results of the fried tofu of the food example 5 (Table 5) and the grilled chicken of the food example 3 (Table 3), the amount of evaporated water was originally small, so the number of exhaust pores could be considerably reduced. did it. However, it was also found that exhaust pores should not be completely eliminated. This also demonstrates that the sum of the diameter of the exhaust pores, the number of the exhaust pores, and the open area can be flexibly set according to the kind of food to be packaged.

[Discussion of the physical range of exhaust pores]
As a result of the microwave heating test (see Tables 1 to 6) for each of a total of six food examples, the range regarding an exemplary exhaust pore can be derived as follows. First of all, according to Table 1, according to the number of exhaust pores, a diameter of 0.59 or 0.50 mm is also acceptable. Furthermore, 0.35 mm was made into the upper limit of a more preferable diameter from coexistence of the performance of steam exhaust, and foreign material contamination suppression. The lower limit of the exhaust pore diameter depends on the performance of the irradiator. However, since the exhaust efficiency of water vapor is reduced when the diameter is extremely narrowed, at least 0.15 mm is required from a series of experimental results, and it is preferably determined to be 0.19 mm, which is the lower limit in the experiment.

  Next, regarding the upper limit of the number of exhaust pores, since the maximum number in Table 1 is 990, it is set to 1000 in anticipation of stable performance. As to the lower limit of the number of exhaust pores, ten of the food examples 6 disclosed in Table 6 were also acceptable. Therefore, the lower limit number is set to eight, preferably ten of the actual tests, in consideration of the five defective samples. This makes it possible to cope with a very wide range of foods.

Subsequently, the sum of the open areas of the exhaust holes (the sum of the open areas of all the exhaust pores on the lid surface) can be calculated from the product of the diameter and the number of the exhaust pores. Thus, the minimum of the total open area is 0.15 mm ² . 0.25 mm ² the lower limit of the total open area this was added the test results in Table 6, and the more preferable lower limit is defined as 0.28 mm ^2. The upper limit of the total open area is 100 mm ² in consideration of Table 1 of food example 1 having a large amount of water, 80 mm ^{2 as} a preferable upper limit, and 50 mm ² as a further preferable upper limit.

  As mentioned above, since the container for microwave oven heating food of the present invention is provided with the exhaust pore formed by the suitable conditions in the lid, the good exhaust of water vapor is realized. Then, it becomes very effective as a substitute of the packaging container for microwave ovens provided with the existing slit structure.

1 Container for food (container for microwave oven heating food)
DESCRIPTION OF SYMBOLS 10, 10x Lid part 11, 11x Lid surface part 15 Peripheral wall part 16 Lid adhesion wall part 20, 20a, 20b, 20c Exhaust hole group 21 Exhaust pore 30 Concave part 35 Lid surface upper peripheral wall part 100 Container main part 103 Inside of container 104 Part 105 Bottom part 106 Opening peripheral wall part 107 Opening step C Food Vp Water vapor

Claims (1)

A lid fitting container comprising: a container body portion for containing food for microwave heating; and a lid portion fitted to the opening portion of the container body portion,
Wherein is Futamen on the peripheral wall portion so as to surround the concave portion and the concave portion is formed in the lid surface of the lid portion,
In the concave portion, an exhaust hole group consisting of a plurality of exhaust fine holes for exhausting water vapor generated from food stored in the container main body to the outside does not have a member for covering or exfoliating the exhaust hole group It is formed ,
The exhaust pore is formed by laser beam irradiation, and
The diameter of the exhaust pore is 0.15 to 0.59 mm,
The number of the exhaust pores is 8 to 1000,
And microwave heating food container, wherein the total opening area of the exhaust pores in the exhaust hole group is to no 0.25 100 mm ^2.

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