JP7657413B2 - Cooking equipment and heat generating units - Google Patents

Description

The present invention relates to a cooking utensil that includes a heat generating agent that generates heat by reacting with water, and a heat generating agent unit used in the cooking utensil.

Heat generating agents that utilize the heat generated by chemical reactions of compounds are highly portable and do not require the use of fire, so they have traditionally been used to heat food and beverages by placing them in lunch boxes or beverage containers, for example, and initiating a chemical reaction by performing a specific operation before eating or drinking.

As an example of a heat generating agent, a chemical reaction in which calcium oxide reacts with water to generate calcium hydroxide is known. As a heating container that can use calcium oxide as a heat generating agent, for example, Patent Document 1 describes a heating container equipped with a heating unit manufactured by a specific method.
On the other hand, since it is difficult to control the amount of heat generated and the rate of temperature rise of a heat generating agent containing calcium oxide as the main component, heat generating agents containing calcium oxide and aluminum as main components, whose amount of heat generated and the rate of temperature rise can be controlled by adjusting the ratio of the amounts of the components and the particle size, etc., are also known as heat generating agents that can be used to heat food and beverages such as boxed lunches (Patent Documents 2 to 5).

Specific examples of containers equipped with heat generating agents for heating such food and beverage products include the following:

Patent Document 6 discloses a heating tool that does not require the application of a large force to a long opening tool when in use and can reliably and uniformly heat food, the heating tool having a water bag in which water is sealed in an easily tearable bag, a support plate with an opening in the center, and a heating agent bag in which a water-permeable bag contains a heating agent that generates heat on contact with water, and a characteristic way in which the long opening tool is wound, as well as a food heating container equipped with the heating tool. However, the materials and configurations of the box, food tray, and lid that make up the food heating container other than the heating tool are said to be the same as those of conventional heating tools.

Patent Document 7 discloses a heating tool that is thin and starts to generate heat in a short time when used and generates a sufficiently large amount of heat even when stored for a long period of time, and a food heating container that can heat food to a sufficiently high temperature in a short time, comprising a watertight container in which a heat generating agent that generates heat when in contact with water and a tearable water bag are stored in a row in the length direction and the upper surface is covered with a tearable film, and a long opening tool, and the area in the watertight container in which the heat generating agent is stored and the area in which the water bag is stored are partitioned by a partition plate with a water passage through which water released by opening the tearable water bag can flow into the area in which the heat generating agent is stored, and a food heating container equipped with the heating tool. Patent Document 7 discloses that the food heating container includes a box body that stores the heating tool at the bottom, a food tray, and a lid body, and that the food stored in the food tray can be supported by a support with a gap formed to form a gas passage in order to heat the food evenly. It is also described that a food tray can be used in which multiple holes are formed in the flange that extends outward from the periphery of the top opening of the food tray without using a support, and this support is said to have the advantage in terms of cost, as it is not necessary to provide the food tray with holes through which high-temperature steam can pass. It is also described that resin or paper materials can be used as the material for the box, with paper being particularly preferable.

Patent Document 8 discloses a string-pulling type chemical heat generating device that induces an exothermic reaction and satisfies all of the following requirements: first, a completely watertight structure to prevent the heat generating agent from absorbing moisture; second, a structure that ensures that the powder heat generating agent does not scatter; third, a minimum number of parts required and a simple manufacturing method to reduce the costs of materials and manufacturing; and fourth, the ability for anyone to easily pull out the pull string to completely and safely cleave the heat generating agent pack and water pack. The device discloses a chemical heat generating device in which the openings of the heat generating tray containing the heat generating agent pack, water pack, and cleavage string for cleaving them are sealed with a protective sheet, as well as a portable food container incorporating the chemical heat generating device.

Patent Document 9 discloses an inexpensive heating element unit that is easy to assemble, reduces manual labor involved in the assembly process compared to conventional methods, is less likely to produce defective products, and has stable quality. The heating element unit is a heating element unit in which a heating agent bag, a separation plate placed in the container so as to cover at least a part of the upper surface of the heating agent bag, and a water bag placed on the upper surface of the separation plate without contacting the heating agent bag are contained in a container having an opening, in which one end of an unsealing member is fixed to a first end of the separation plate, extends from the first end to the second end of the separation plate on the lower surface of the water bag, and the other end is led out from the container to the outside so that the number of folds in the container is 0 or 1, and is also provided with a sealing sheet that seals the opening. It also discloses a heating element unit and a manufacturing method thereof, as well as a heating container that includes the heating element unit, a box, a tray member, and a lid.

JP 2010-184039 A Patent No. 3467729 Patent No. 3778213 Patent No. 3921550 Patent No. 4008490 JP 2008-089214 A JP 2009-248981 A JP 2010-068846 A JP 2015-077282 A

Many of the various containers described in Patent Documents 6 to 9 are characterized by a drawstring mechanism for the heat generating agent, and the box that contains the heat generating agent at the bottom may be of any shape, or no particular shape may be mentioned. Even with general food packaging containers (boxes and food trays) available on the market, the edges are often flat in appearance, as they come into contact with the mouth when eating or drinking, or are touched when held in the hand.

On the other hand, the preferred temperature for food is generally considered to be within ±25 to 30 degrees Celsius of body temperature, with around 60 to 65 degrees Celsius being preferred for warm foods (Sato Yumiko, Kobayashi Sachiko, "Serving temperature and temperature changes at the time of eating in mass school lunches," Bulletin of Wayo Women's University, Vol. 33 (Home Economics Edition)).
When it is desired to use the heat generating agent to heat food or drink to a temperature suitable for eating, in principle, the amount of heat generating agent used can be increased since the amount of heat generating agent is proportional to the amount of heat generating agent. However, if the amount of heat generating agent used increases, the container in which the heat generating agent is stored also becomes larger accordingly, which may cause inconvenience to the user when the heat generating agent is used, particularly when the heat generating agent is used for lunch boxes or other items that require the user to hold the container in their hands to eat or drink. Therefore, a heat generating agent that generates heat efficiently with as little heat as possible is desired.
In addition, reducing waste is an important element in the effort to achieve a decarbonized society. The heat generating agent is discarded after use, i.e., after the exothermic reaction, and it is desirable to use a heat generating agent with as high heat generating efficiency as possible, taking the environment into consideration.
The inventors then conducted an investigation using the heat generating agent described in Patent Document 5, which is said to have a high unit heat output, and found that if the container on the bottom of which the heat generating agent is placed has a flat shape with no shaping of the peripheral edge of the container as described above, the container is likely to deform due to the heat of the water vapor, causing gaps in the deformed areas and allowing water vapor to easily leak out of the container through these gaps.

The present invention therefore aims to provide a cooking utensil that can safely heat food to be cooked, such as by heating, in a short time, so that it can be eaten.

As a result of intensive research into solving the above problems, the inventors discovered that the following cooking utensils can solve the above problems, and thus completed the present invention.

That is, the present invention provides the following cooking utensil.
[1]
A cooking utensil comprising a container body, a food container, a lid, and a heat generating agent unit,
The container body has a bottom on which a heat generating agent unit can be placed, an opening on an upper portion, and at least one recess on a peripheral portion,
The food container is placed on the container body, can accommodate food to be cooked therein, and has at least one steam hole;
The lid is adapted to cover the food container to form an internal space in the food container,
The heat generating agent unit comprises a heat generating agent unit container, a heat generating agent containing at least aluminum metal powder and calcium oxide sealed in a water-permeable outer casing, a water bag having a tear portion, and a string, wherein the heat generating agent is placed on the bottom of the heat generating agent unit container, the water bag is placed on top of the heat generating agent so as to fix the tear portion to one end of the heat generating agent unit container, one end of the string is fixed to the other end of the heat generating agent unit container, the other end of the string extends from the other end of the heat generating agent unit container toward the one end of the heat generating agent unit container to which the tear portion is fixed, and is folded back at one end of the heat generating agent unit container to sandwich the water bag, and reaches the outside of the container body.
[2]
The cooking utensil according to claim 1, wherein one of the recesses on the peripheral edge of the container body is a guide portion for leading the other end of the cord of the heat generating agent unit to the outside of the container body.
[3]
The heat generating agent is
(A-1) Metal aluminum powder having a particle size distribution in which the particle size at 45 μm pass is 70.0 to 80.0% and the particle size at 45 to 75 μm is 20.0 to 30.0%;
(A-2) Aluminum metal powder having a particle size distribution of 60-70% particle size 45 μm pass, 20-30% particle size 45 μm, 7-10% particle size 63 μm, and 1.0-2.0% particle size 75 μm;
and (B) calcium oxide having an average particle size of 75 μm to 150 μm, in a mass ratio of (A-1):(A-2)=1:2, the total of (A-1) and (A-2) being 60 mass% or more and less than 70 mass%, and the (B) component being more than 30 mass% and 40 mass% or less, relative to the mass of the heat generating agent. The cookware according to [1] or [2].

The present invention also provides the following heat generating unit that can be suitably used in the cooking utensil and is suppressed from deteriorating over time.
[4]
A heat generating agent unit including a heat generating agent unit container, a heat generating agent containing at least aluminum metal powder and calcium oxide sealed in a water-permeable exterior body, a water bag having a tearing section, and a string body, the heat generating agent unit being contained in a non-water-permeable film packaging,
A heat generating agent unit in which the heat generating agent is placed on the bottom of the heat generating agent unit container, the water bag is placed on top of the heat generating agent so as to fix the tear portion to one end of the heat generating agent unit container, one end of the string is fixed to the other end of the heat generating agent unit container, the other end of the string extends from the other end of the heat generating agent unit container toward the one end of the heat generating agent unit container to which the tear portion is fixed, and is folded back at one end of the heat generating agent unit container to sandwich the water bag, and is not extended outside the non-permeable film packaging.

The cooking utensil of the present invention can efficiently use the heat generated by the heat generating agent to cook the target food, making it possible to eat the food in a short time. In addition, the cooking utensil of the present invention can prevent water vapor from escaping through gaps caused by unintended deformation of the container body, making it safe for diners.

1 is an exploded perspective view showing an example of a cooking utensil of the present invention. 1 is a plan view showing an example of a lid 30 used in the cooking utensil of the present invention. FIG. 2 is a plan view showing an example of a food container 20 used in the cooking device of the present invention. FIG. 2 is a plan view showing an example of a heat generating agent unit container 41 used in the cooking utensil of the present invention. 1 is a plan view showing an example of a container body 10 used in a cooking utensil of the present invention. These are cross-sectional views of the food container taken along the lines AA in Figure 2A-1, A'-A' in Figure 2A-2, A''-A'' in Figure 2A-3, and A'''-A''' in Figure 2A-4. These are cross-sectional views of food containers cut along the cutting lines BB in Figure 2A-1, B'-B' in Figure 2A-2, B''-B'' in Figure 2A-3, and B'''-B''' in Figure 2A-4. FIG. 2 is a perspective view showing an example of a food container used in the cooking device of the present invention. FIG. 11 is a perspective view showing another example of a food container used in the cookware of the present invention. FIG. 2 is a perspective view showing an example of a heat generating agent unit contained in a water-impermeable film package of the present invention.

The present invention will be described in detail below.
In the present invention, cooking includes not only heating or warming cooked foods, semi-cooked foods, or processed foods such as frozen, chilled, and retort pouched foods to a temperature suitable for eating, but also steaming or boiling unprocessed foods, semi-processed foods, or processed foods such as frozen, chilled, and retort pouched foods.

The cooking utensil of the present invention will now be described with reference to the drawings.
FIG. 1 is an exploded perspective view showing an example of a cooking utensil according to the present invention.
Fig. 2A-1 is a plan view showing an example of a lid 30 used in the cooking utensil of the present invention. Fig. 2A-2 is a plan view showing an example of a food container 20 used in the cooking utensil of the present invention. Fig. 2A-3 is a plan view showing an example of a heat generating agent unit container 41 used in the cooking utensil of the present invention. Fig. 2A-4 is a plan view showing an example of a container body 10 used in the cooking utensil of the present invention.
FIG2B-1 is a cross-sectional view of the food container 1 taken along the cutting lines A-A in FIG2A-1, A'-A' in FIG2A-2, A''-A'' in FIG2A-3, and A'''-A''' in FIG2A-4. FIG2B-2 is a cross-sectional view of the food container 1 taken along the cutting lines B-B in FIG2A-1, B'-B' in FIG2A-2, B''-B'' in FIG2A-3, and B'''-B''' in FIG2A-4.

The cooking utensil 1 of the present invention comprises a container body 10, a food container 20, a lid 30, and a heat generating agent unit 40.
The container body 10 is capable of mounting a heat generating agent unit on its bottom 12, has an opening on its upper portion, and has at least one recess 11 a on its peripheral portion 11.
The food container 20 is placed over the container body 10, is capable of accommodating food to be cooked therein, and has at least one steam hole 21.
The lid 30 is placed on the food container 20 to form an internal space in the food container 20 .
The heat generating agent unit 40 includes a heat generating agent unit container 41, a heat generating agent 42 containing at least aluminum metal powder and calcium oxide sealed in a water-permeable exterior body, a water bag 43 having a tearing portion 43a, and a string 44. The heat generating agent unit 40 is configured such that the heat generating agent 42 is placed on the bottom of the heat generating agent unit container 41, the water bag 43 is placed on the heat generating agent 42 so as to fix the tearing portion 43a to one end 41b of the heat generating agent unit container 41, one end 44a of the string 44 is fixed to the other end 41a of the heat generating agent unit container 41 as a fixed end, and the other end of the string 44 extends from the other end 41a of the heat generating agent unit container toward the one end 41b of the heat generating agent unit container to which the tearing portion 43a is fixed as a free end, is folded back at the one end 41b of the heat generating agent unit container so as to sandwich the water bag 43, and reaches the outside of the container body 10.

Container body The container body 10 can place the heat generating agent unit 40 on the bottom 12, has an opening at the top, and has at least one recess 11a on the periphery 11. By having at least one recess 11a on the periphery 11 of the container body 10, it is possible to prevent the deformation of the periphery 11 of the container body 10 due to the heating of steam and the occurrence of a gap between the container body 10 and the food container 20 caused by this deformation, and to prevent the leakage of steam to the outside. That is, the recess 11a on the periphery 11 of the container body 10 can improve the fit between the container body 10 and the food container 20 or the lid 30 during or after the use (heat generating agent reaction) of the cooking utensil of the present invention. The peripheral portion 11 of the container body 10 has at least one recess 11a, and it is preferable to have multiple recesses (two or more) at any interval. 1, there are six recesses 11a on the peripheral portion 11 of the container body 10, but this is not limited to this. When there are two or more recesses 11a, the recesses can be arranged on the peripheral portion at intervals of, for example, 3 to 4 cm.
As shown in FIG. 1 and FIG. 2A-4, the recess 11a is preferably recessed in a direction perpendicular to the periphery.

The other end (free end) of the string 44 of the heat generating agent unit 40 may be fixed to the outside of the container body 10 through a recess 11a on the peripheral portion 11 of the container body 10. That is, one of the recesses 11a on the peripheral portion 11 of the container body 10 may be a portion for guiding the other end of the string 44 of the heat generating agent unit 40 to the outside of the container body 10. The other end (free end) of the string 44 of the heat generating agent unit 40 may be drawn to the outside of the container body 10 by providing a hole on any side of the container body 10 and fixed thereto, but it is preferable to guide the other end (free end) of the string 44 of the heat generating agent unit 10 to the outside of the container body 10 through the recess 11a on the peripheral portion 11 of the container body 10 and fix it thereto, because the water vapor generated in the heat generating agent unit 40 can flow out from the hole, friction when pulling the string can be reduced, and the effort of opening a hole and passing the string 44 through can be omitted.

When using the cooking utensil 1 of the present invention, if steam is generated unevenly, the heating efficiency of the food being cooked may decrease. Therefore, it is preferable that the bottom 12 of the container body 10 has a protrusion 12a that conforms to the shape of the bottom of the heat generating agent unit container 41 so that the heat generating agent unit 40 can be placed thereon and to join the container body 10 and the heat generating agent unit 40.

The material of the container body 10 is not particularly limited, and materials that are usually used for containers for food and beverages can be used, such as various resins, metal, glass, ceramics, paper with a waterproofing treatment on the inside, and wood. Among them, various resins are preferable, and examples of the various resins include polyethylene, polypropylene, polystyrene, polyvinyl chloride, polyethylene terephthalate, polycarbonate, nylon, melamine, silicone, and foams of these resins. The various resins may be composed of one type, or may be a combination of two or more types by lamination or the like. Expanded polystyrene is preferable because of its excellent heat resistance and insulation properties, and expanded polystyrene in which the inside of the container body is laminated with polypropylene is particularly preferable.

Food container The food container 20 is placed over the container body 10 and can hold the food to be cooked inside.It has at least one steam hole 21 to allow water vapor generated by the reaction between the heat generating agent and water in the heat generating agent unit 40 to circulate into the space formed by the food container 20 and the lid 30.

The steam hole 21 may be located on the periphery or bottom of the food container 20 depending on the type of food to be cooked and the purpose of cooking that is contained in the food container 20. For example, when food that is the same size as the steam hole 21, such as cooked rice, is to be contained in the food container 20, it is preferable that there are no gaps in the bottom of the food container 20, so it is preferable to have a steam hole on the periphery of the food container 20.

Furthermore, the shape of the steam hole is not particularly limited and can be determined appropriately depending on the type of food to be cooked contained in the food container 20 and the purpose of cooking.
Fig. 3 is a perspective view showing an example of a food container 20 used in the cooking utensil of the present invention. When heating food to a temperature suitable for eating in a short time, the steam hole 21 can be a U-shaped or other notch as shown in Fig. 1, but the shape of the notch is not limited to a U-shape and may be any curved shape such as a C-shape or a wavy shape. On the other hand, when cooking low-temperature food at a high temperature, the steam hole 21 can be a through hole of any shape such as a circular hole, an elliptical hole, or a slit as shown in Figs. 3A and B.
In order to heat the food to be cooked evenly, it is preferable to have a plurality of steam holes 21.

The food container 20 may have any shape as long as it can accommodate the food to be cooked.
For example, the longitudinal side surfaces may not be flat, but may be formed as continuous uneven portions 20b as shown in FIG. 1, thereby increasing the surface area and improving the efficiency of heating the food to be cooked.
In addition, during the manufacturing process, in order to enable stacking of multiple food containers 20 with food contained therein and the lid bodies 30 stacked on top of each other, convex portions 20a may be provided at the four corners of the bottom of the food container 20, and concave portions 30a may be provided at the four corners of the upper surface of the lid body 30 described below.

The material of the food container 20 can be any material that is typically used for food containers, and specifically can be the same as the various materials exemplified for the container body 10. The material of the food container 20 can be the same as that of the container body 10 or a different material.

Heat Generating Agent Unit The heat generating agent unit 40 is composed of a heat generating agent unit container 41, a heat generating agent 42 containing at least aluminum metal powder and calcium oxide sealed in a water-permeable exterior body, a water bag 43 having a tearable portion, and a string 44.
The heat generating agent 42 is placed on the bottom of the heat generating agent unit container 41, and the water bag 43 is placed on the heat generating agent 42, with the tearable portion 43a of the water bag 43 fixed to one end 41b of the heat generating agent unit container 41. One end 44a of the string 44 is fixed to the other end 41a of the heat generating agent unit container 41 as a fixed end. The other end 41a of the heat generating agent unit container 41 to which the one end 44a of the string 44 is fixed and the one end 41b of the heat generating agent unit container 41 to which the tearable portion 43a of the water bag 43 is fixed are positioned opposite each other. The other end of the string 44 is a free end that extends from the other end 41a of the heat generating agent unit container 41 toward one end 41b of the heat generating agent unit container 41 to which the tear portion 43a is fixed, and is folded back at one end 41b of the heat generating agent unit container 41 so as to sandwich the water bag 43, and is led out to the outside of the container body 10.

Cord The cord 44 is not particularly limited as long as it has a tensile strength normally used to tear open the water bag 43 .

Water bag The water bag 43 is a bag with a tearing section that contains water in an amount determined according to the amount of heat generating agent. The water bag 43 is preferably a bag in which water is contained in a resin film with low water vapor permeability and excellent in ease of opening, which is easily torn by the force applied by pulling the string body 44. As the material of the bag, materials that are usually used for water bags used together with heat generating agents can be used. For example, the resin film can be a resin film such as polyethylene, polypropylene, polyester, polyamide, polycarbonate, polyvinyl chloride, and copolymers thereof, which has been subjected to uniaxial stretching treatment. The resin film may be one type of single layer film or two or more types of multilayer film. When the heat generating agent unit is to be stored for a long period of time, a bag that is further aluminum-deposited or aluminum foil-laminated may be used to reduce the water vapor permeability of the water bag 43.
In addition, the tearing portion 43a of the water bag may be provided with a notch to facilitate tearing using the string.
The amount of water contained in the water bag 43 is, for example, 1.0 to 10.0 times, and more preferably 3.0 to 4.0 times, the mass of the heat generating agent.

Heat generating agent The heat generating agent contains aluminum metal powder and calcium oxide. The heat generating agent preferably contains aluminum metal powder and calcium oxide as main components. The main component means that the total content of aluminum metal powder and calcium oxide among all the components of the heat generating agent is preferably 50 mass% or more, more preferably 70 mass% or more, and even more preferably 85 mass% or more.

The particle size of the aluminum metal powder contained in the heat generating agent is preferably 3 to 500 μm, and more preferably 3 to 250 μm. In this specification, the particle size of the aluminum metal powder refers to the cumulative diameter of 50% sieving on a mass basis measured in accordance with the general rules for sieving test methods specified in JIS Z8815. Aluminum metal powders with different particle sizes may be used in combination.

The calcium oxide contained in the heat generating agent is preferably of high purity.

As the heat generating agent used in the present invention, it is preferable to use the heat generating agent described in Patent Document 5. Specifically, it is particularly preferable to use a heat generating agent containing the following (A-1), (A-2), and (B) in the following composition.

(A-1) Metal aluminum powder having a particle size distribution in which the particle size 45 μm pass is 70.0 to 80.0%, and the particle size 45 to 75 μm is 20.0 to 30.0%.

(A-2) Aluminum metal powder having a particle size distribution of 60-70% particle size 45 μm pass, 20-30% particle size 45 μm, 7-10% particle size 63 μm, and 1.0-2.0% particle size 75 μm

(B) Calcium oxide having an average particle size of 75 μm to 150 μm

The mass ratio of (A-1):(A-2) is 1:2, the sum of (A-1) and (A-2) is 60 mass% or more and less than 70 mass%, and the (B) component is more than 30 mass% and 40 mass% or less, based on the mass of the heat generating agent.

The heat generating agent may contain, in addition to aluminum metal powder and calcium oxide, an inorganic salt compound, a metal oxide, a metal hydride, etc. as a reaction promoter, so long as the effect of the present invention is not impaired. Examples of the reaction promoter include calcium sulfate, ferrous sulfate, magnesium chloride, sodium sulfite, sodium phosphate, sodium carbonate, etc. The amount of the reaction promoter is preferably less than 50 mass%, more preferably less than 30 mass%, and even more preferably 5 to 10 mass% of the total mass of the heat generating agent.
The heat generating agent may be in the form of a powder or pellets.

The material of the exterior body in which the heat generating agent is enclosed is preferably one having an air permeability of 5 to 90 cc/ ^cm2 ·sec, more preferably 7 to 50 cc/ ^cm2 ·sec, as measured by the Frazier method. By using an exterior body having an air permeability in the above range, water can be sufficiently supplied into the exterior body to react with the heat generating agent. Examples of the material of the exterior body include nonwoven fabric and water-permeable film.

The manufacturing method of the exothermic agent is not particularly limited, but may be a method of uniformly mixing aluminum metal powder, calcium oxide, and optionally a reaction accelerator in the above-mentioned ratio using a known powder mixer. The mixture (exothermic agent) thus obtained is either in powder form or formed into pellets, and then enclosed in an exterior body using a known powder filling and packaging machine or the like. The opening of the exterior body after filling with the exothermic agent is sealed by a known method such as heat sealing. The filling rate of the exothermic agent in the exterior body is preferably 95% or less.
The heat generating agent enclosed in the exterior body may be stored in a moisture-impermeable container, and the moisture-impermeable container may be opened immediately before the heat generating agent unit is produced, and the heat generating agent may be placed in the heat generating agent unit container.
Commercially available heat generating agents of this kind include "EDIC SUPERHEAT" (registered trademark) from PAL Corporation.

The heat generating agent containing the above (A-1), (A-2), and (B) in the above composition or the above commercially available heat generating agent has a high average water vapor temperature of 90°C or higher 1 to 30 minutes after the start of the reaction with water, as measured by the following method, and has excellent heat generating performance, and is therefore preferably used in the cooking utensil of the present invention.
[Water vapor temperature measurement method]
A stainless steel reaction vessel covered with a thermal insulator having a volume of 410 ^cm3 was used, 15 g of heat generating agent was placed on the bottom of the reaction vessel, the reaction vessel was covered with a lid, 40 mL of water was added through a water inlet provided in the lid, and the water vapor temperature was measured with a K thermocouple provided on the inside of the lid so as to measure the temperature inside the reaction vessel. A more specific method for measuring the water vapor temperature can be performed by the method described in the Examples below.

Heat generating agent unit container The heat generating agent unit container 41 may have any shape as long as it fits into the bottom of the container body 10 and can accommodate the heat generating agent 42 and the water bag 43. In order to allow the heat generating agent 42 to react with a desired amount of water in the heat generating agent unit container 41, the volume of the heat generating agent unit container 41 is preferably larger than the total volume of the heat generating agent 42 and the water in the water bag 43. In addition, in order to allow the heat generating agent 42 and the water bag 43 to be placed in the heat generating agent unit container 41 and to increase the reaction efficiency of the heat generating agent 41, it is preferable that at least the bottom of the heat generating agent unit container 41 has a flat shape on which the heat generating agent 42 is placed, and it is preferable that the surface on which the heat generating agent 42 is placed does not have an uneven shape that may cause water to be unevenly distributed when the water bag 43 is opened.
Furthermore, as long as the mounting surface for the heat generating agent 42 is flat, for example, the bottom of the heat generating agent unit container 41 may have a convex portion 41c parallel to the longitudinal or lateral direction to prevent the heat generating agent 42 from moving within the heat generating agent unit container 41.

It is also preferable that the other end 41a of the heat generating agent unit container 41 has a notch for fixing one end 44a of the string 44. For example, a knot is made by knotting a knot or the like to fix one end 44a of the string 44 so that the string does not come loose, and the knot is fixed below the notch provided in the other end 41a of the heat generating agent unit container 41.

The water bag 43 has a tearable portion 43a fixed to the heat generating agent unit container 41 so that it can be torn open by the force of pulling the string. The position at which the water bag 43 is fixed is the other end 41b opposite to the other end 41a of the heat generating agent unit container 41, where one end 44a of the string 44 is fixed. Methods for fixing the water bag 43 include a method of fixing the tearable portion 43a of the water bag 43 to one end 41a of the heat generating agent unit container 41 using a stapler, adhesive, high-frequency welder, etc.

In addition, if the heat generating agent unit container 41 is deformed by the force applied by the string pulling, the water bag 43 may not be ruptured, so the heat generating agent unit container 41 is preferably one having a moderate strength. The material of the heat generating agent unit container 41 is not particularly limited, but it is preferable that the material is heat-resistant since the heat generating agent comes into contact with the heat generating agent, and water-resistant since the heat generating agent comes into contact with the water ruptured from the water bag. Specific examples of the material of the heat generating agent unit container 41 include the various resins listed as the material of the container body. In addition, in consideration of environmental issues, a resin containing bioplastic may be used as the material of the heat generating agent unit container 41. Furthermore, as with the container body, the various resins may be composed of one type, or may be combined by lamination or the like of two or more types.
In addition, the side surface of the other end 41a of the heat generating agent unit container 41, which fixes the tearing portion 43a of the water bag 43, is preferably shaped to increase the strength of the heat generating agent unit container, and for example, the other end 41a of the heat generating agent unit container 41 has a reinforcing portion 41d. The reinforcing portion 41d may be flat as shown in Fig. 1, or may be further processed into a rib shape.

FIG. 4 is a perspective view showing an example of a heat generating agent unit contained in a packaging body made of a non-water permeable film.
The heat generating agent unit 40 used in the present invention may be pillow-packaged with a non-permeable film 40a such as an aluminum film to cover the heat generating agent unit 40, in order to prevent deterioration of its performance as a heat generating agent due to the progress of a chemical reaction of the heat generating agent caused by water vapor in the air.
That is, the heat generating agent unit 40 of the present invention may be a pillow package comprising a heat generating agent unit container, a heat generating agent containing at least aluminum metal powder and calcium oxide sealed in a water-permeable exterior body, a water bag having a tearing part, and a string, as described above, and the heat generating agent unit is contained in a non-water-permeable film package. Here, the heat generating agent unit of the present invention, which is a pillow package, is characterized in that one end of the string is fixed to the other end of the heat generating agent unit container, the other end of the string extends from the other end of the heat generating agent unit container toward the one end of the heat generating agent unit container to which the tearing part is fixed, and is folded back at the one end of the heat generating agent unit container so as to sandwich the water bag, and is not led out to the outside of the non-water-permeable film package.
In conventional heat generating agent units, there are known units in which the upper surface of the heat generating agent unit is top-sealed with a non-permeable film to prevent deterioration of the heat generating agent over time (for example, Patent Documents 7 and 9). However, in order to secure the string to the outside of the container body, the string needs to be pulled out from the top-sealed area, which creates a small gap at the top-sealed area, making it difficult to completely prevent deterioration of the heat generating agent over time. The heat generating performance of the heat generating agent remains almost unchanged from the initial state for only about three months or at most one year after the top-sealed heat generating agent unit is produced.
Another known heat generating agent unit for preventing deterioration of the heat generating agent over time is one in which each component of the heat generating agent unit is sealed in a water-impermeable film bag or the like (for example, Patent Document 6). However, this type of heat generating agent unit is also placed directly into a lunch container or the like, so the string is pulled out to the outside of the water-impermeable film bag and the bag is not completely sealed, and as with the top-sealed heat generating agent unit, it is difficult to completely prevent deterioration of the heat generating agent over time.
Therefore, although it is desirable to use conventional heat generating units in lunch containers, etc. immediately after production to prevent deterioration of the heat generating agent over time, it can sometimes be difficult to make such adjustments from the perspective of production costs, such as inventory management.
On the other hand, in the heat generating agent unit that is a pillow package of the present invention, the string is confined within the pillow package and does not extend outside the non-permeable film envelope, and no gaps are formed in the pillow package, so there is no risk of deterioration of the heat generating agent over time, and the heat generating performance of the heat generating agent remains almost unchanged even about five years after the pillow packaged heat generating agent unit is produced. Therefore, depending on the ordering situation of lunch boxes, etc., the pillow package can be opened at the appropriate time, the heat generating agent unit in which the heat generating agent has not deteriorated can be placed on the bottom of the container body, and the string can be fixed to the outside of the container body, so that the heat generating agent unit that is a pillow package of the present invention is preferable in terms of both the heat generating performance of the heat generating agent and manufacturing costs.

Lid The lid 30 covers the opening of the food container 20, prevents water vapor generated by the reaction between the heat generating agent 42 and water from leaking out, and effectively heats the food contained in the food container 20 to the desired temperature, and a lid that is normally used for lunch boxes and the like can be used. In order to efficiently cook the target food, such as by heating it, it is preferable that the lid be a fitting lid that does not leave a gap with the container body 10 or the food container 20. The fitting lid may be any of an outer fitting lid, an inner fitting lid, and an inner and outer fitting lid.
In practical use, depending on the type of food contained in the food container 20, after the food is contained in the food container 20, the food container 20 may be covered with the lid 30 and stored, for example, in a refrigerator until it is sold. Therefore, for convenience of storage, the lid 30 may have recesses 30a at the four corners thereof that correspond to the shape of the four corners 20a of the food container 20 so that multiple food containers 20 can be stacked.

The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples.

[Exothermic agent]
The heat generating agent used had the composition shown below.
Heat generating agent 1:
(A-1) Metal aluminum powder having a particle size distribution in which the particle size at 45 μm pass is 70.0 to 80.0% and the particle size at 45 to 75 μm is 20.0 to 30.0%;
(A-2) Aluminum metal powder having a particle size distribution of 60-70% particle size 45 μm pass, 20-30% particle size 45 μm, 7-10% particle size 63 μm, and 1.0-2.0% particle size 75 μm;
and (B) calcium oxide having an average particle size of 75 μm to 150 μm, in a mass ratio of (A-1):(A-2) = 1:2, the total of (A-1) and (A-2) being 60 mass% or more and less than 70 mass%, and the (B) component being more than 30 mass% and not more than 40 mass%, per mass of the heat generating agent, the mixed powder being enclosed in a water-permeable exterior nonwoven fabric (manufactured by Unicel Corporation).

[Measurement of water vapor temperature of exothermic agent]
In order to confirm the heat generating properties of the heat generating agent, the temperature of the water vapor generated by reaction with water was measured by the following method.
15 g of the exothermic agent was placed on the bottom of a SUS reaction vessel having a volume of 410 ^cm3 , and the reaction vessel was covered. The reaction vessel lid had a water inlet for adding water to be used in the reaction, and a K thermocouple (digital data logger thermometer TM-97SD) was installed on the inside of the lid so that the temperature inside the vessel could be measured. The reaction vessel was covered with a heat insulating material so that it would not be affected by the outside air during the measurement. 45 mL of water was added from the water inlet to start the reaction between the exothermic agent and water. The time when the water was added was set as 0 minutes after the start of the reaction, and the temperature of the K thermocouple was read and recorded every 5 seconds thereafter.
The steam temperature was measured by the above method, and the average values of the measured temperatures from 1 to 30 minutes after the start of the reaction were calculated, as follows:
Heat generating agent 1: 91.6℃

[Cooking Utensils]
Cooking utensil 1 (a cooking utensil having the shape shown in FIG. 1)
Container body: A polystyrene foam container with an approximately rectangular parallelepiped shape with outer dimensions of 220 mm x 120 mm x 65 mm and a thickness of 2.0 mm, the inside of which is laminated with polypropylene. Food container: A polypropylene container with an approximately rectangular parallelepiped shape with outer dimensions of 220 mm x 120 mm x 45 mm, and a total of four U-shaped steam holes (notches) on the periphery in the short direction (two on each side) Container/cookware 2 (for comparison)
A cooking utensil similar to the cooking utensil 1 described above except that the container body does not have a recess on the periphery.

[Measurement of temperature inside food container]
Using the cooking utensils and exothermic agents of each example shown below, 400 mL of water was placed in the food container as the object to be cooked, and a heating agent unit containing 30 g of heating agent and 80 mL of water in a water bag was placed on the bottom of the container body, and the reaction of the heating agent was started by pulling the string, and the temperature of the water, which was the object to be cooked, was measured with a K thermocouple (digital data logger thermometer TM-97SD). In order to simulate actual use and to equalize the temperature before the test, the cooking utensils containing the test object water were stored in a refrigerator for 2 hours before measurement and used for the test. The reaction between the heating agent and the water was started by pulling the string, and the temperature of the K thermocouple was read and recorded every 5 seconds from the start of the reaction until 20 minutes later.
The temperature was measured at two points for each measurement. The temperature measurement results were evaluated based on the temperature change ΔT from the initial reaction temperature, and the average value of the measurement results at the two points was calculated.
First, the time required for ΔT to reach the maximum value (ΔTmax) was calculated.
Furthermore, the Ministry of Health, Labour and Welfare lists "heating food to a temperature of 75°C at the center for at least one minute" as a guideline for preventing food poisoning. Taking into consideration that the temperature measurement position is not the center of the food container, the duration that satisfies ΔT = 55°C or more (time duration of Δ55°C or more) was calculated in order to use the time when the temperature measurement point reaches 80°C or more as an index, assuming the temperature at the standard condition SATP to be 25°C.
Furthermore, if the body temperature is 36° C. and the temperature change suitable for eating is +25° C., the temperature suitable for eating food is 61° C. Therefore, taking into account the temperature of 25° C. in the standard condition (SATP), the time required for ΔT to reach 36° C. (Δ36° C. arrival time) was calculated.

[Comparative Example 1]
First, the temperature change of 400 mL of water contained in the food container portion was measured using the cooking utensil 2 on which the heat generating agent 1 was placed. The results are shown in Table 1 below.

After measuring the temperature change in Comparative Example 1, the food container was removed from the container body and the shape of the container body was checked. It was found that the center in the longitudinal direction was particularly bent inward. The dimensional changes in the periphery of the container body before and after the temperature change measurement were measured at the center of each of the two longitudinal sides, and were 10.5 mm and 11.0 mm, respectively.

[Example 1]
Next, the temperature change of 400 mL of water contained in the food container portion was measured using the cooking utensil 1 on which the exothermic agent 1 was placed. The results are shown in Table 1 below.
Furthermore, similarly to Comparative Example 1, after measuring the temperature change, the dimensional changes at the center of each of the two longitudinal sides of the container body were measured and found to be 4.00 mm and 0.5 mm, respectively.

In Example 1 using the cooking utensil 1 of the present invention, it was found that the temperature ΔTmax was high and reached ΔTmax in a short time. In Example 1, the duration of Δ55°C or higher was 14.50 minutes, which was approximately 3/4 of the 20 minutes of temperature measurement time, and the time to reach Δ36°C was 2.92 minutes, which meant that the temperature reached a suitable temperature for eating within 3 minutes.
On the other hand, in Comparative Example 1, in which a cooking utensil 2 having no recess on the periphery of the container body was used, the deformation of the container body due to the reaction of the exothermic agent was more significant than in the Examples. In Comparative Example 1, ΔTmax was 2.00°C or more lower than in Example 1, the time to reach ΔTmax was longer than in Example 1, the duration of Δ55°C or more was shorter than in Example 1, and the time to reach Δ36°C was slower than in Example 1. The above temperature characteristics are considered to be due to the fact that a gap was created between the food container and the container body due to the deformation of the container body, and the amount of water vapor that was generated and flowed out of the container without being used to heat the food was greater than in Example 1.
From the above, it has been found that the cooking utensil of the present invention can efficiently utilize the steam generated by the reaction of the heat generating agent to heat the target food, can maintain a high temperature for a long period of time, and quickly reaches a temperature suitable for eating.

[Example 2]
The ΔTmax of Comparative Example 1 was used as an index of the temperature achieved when the previous container was used, and in order to investigate how much the amount of heat generating agent had to be reduced to achieve the ΔTmax of Comparative Example 1 under the conditions of Example 1, the temperature inside the food container was measured in the same manner as in Example 1, except that the amount of heat generating agent was changed.
A ΔTmax equivalent to that of Comparative Example 1 was shown when the amount of heat generating agent in Example 1 was reduced from 30 g to 26 g, and the ΔTmax was 65.50° C.
In other words, it was found that by using the cooking utensil of the present invention, the amount of heat generating agent can be reduced by about 13% to achieve the same heating temperature as the conventional container. Therefore, the container of the present invention can reduce the amount of heat generating agent, and therefore the amount of waste.

The cooking utensil of the present invention can be used to heat the target food without waste by utilizing the heat generated by the reaction of the heat generating agent with water, making it ideal for heating, cooking, and keeping warm food that is highly portable, such as in boxed lunches.

1 Cooking utensil 10 Container body 11 Periphery 11a Concave 12 Bottom 12a Convex 20 Food container 20a Convex 20b Concave 21 Steam hole 30 Lid 30a Concave 40 Heat generating agent unit 40a Non-permeable film 41 Heat generating agent unit container 41a Other end of heat generating agent unit container 41b One end of heat generating agent unit container 41c Reinforcement 42 Heat generating agent 43 Water bag 43a Tear section 44 String 44a One end of string (fixed end)

Claims (2)

A cooking utensil including a resin container body, a food container, a lid, and a heat generating agent unit,
The container body has a bottom on which a heat generating agent unit can be placed, an opening on an upper portion, and two or more recesses on a periphery that are recessed in a direction perpendicular to the periphery ,
The food container is placed on the container body, can accommodate food to be cooked therein, and has at least one steam hole;
The lid is adapted to cover the food container to form an internal space in the food container,
The heat generating agent unit comprises a heat generating agent unit container, a heat generating agent containing at least aluminum metal powder and calcium oxide sealed in a water-permeable outer casing, a water bag having a tear portion, and a string, wherein the heat generating agent is placed on the bottom of the heat generating agent unit container, the water bag is placed on top of the heat generating agent so as to fix the tear portion to one end of the heat generating agent unit container, one end of the string is fixed to the other end of the heat generating agent unit container, the other end of the string extends from the other end of the heat generating agent unit container toward the one end of the heat generating agent unit container to which the tear portion is fixed, and is folded back at one end of the heat generating agent unit container to sandwich the water bag, and reaches the outside of the container body. The heat generating agent is
(A-1) Metal aluminum powder having a particle size distribution in which the particle size at 45 μm pass is 70.0 to 80.0% and the particle size at 45 to 75 μm is 20.0 to 30.0%;
(A-2) Aluminum metal powder having a particle size distribution of 60-70% particle size 45 μm pass, 20-30% particle size 45 μm, 7-10% particle size 63 μm, and 1.0-2.0% particle size 75 μm;
and (B) calcium oxide having an average particle size of 75 μm to 150 μm, in a mass ratio of (A-1):(A-2)=1:2, the total of (A-1) and (A-2) being 60 mass% or more and less than 70 mass%, and the (B) component being more than 30 mass% and 40 mass% or less, per mass of the heat generating agent.

Images