JP6389076B2 - Method for producing food containers - Google Patents

Description

  The present invention relates to a container for putting food such as liquid or solid into the container, which can prevent the occurrence of sparks during heating in a microwave oven, and a method for manufacturing the same.

  Containers containing a metal layer are widely used as food containers because of their excellent gas barrier properties. However, when a food filled in a container containing such a metal layer is heated in a microwave oven, a glass is conventionally used. Food was transferred to a plastic container or a ceramic container and then heated in a microwave oven. The reason for this transfer of food is that when a container containing a metal layer is used in a microwave oven, sparks may occur in the metal layer exposed at the flange end of the container, and the container may burn. This is because there were problems such as affecting the quality of the food of the contents.

In order to solve the above problems when a container including a metal layer is used in a microwave oven, Patent Document 1 discloses that a container having a configuration in which both surfaces of a metal foil are coated with a thermoplastic resin, the flange end of the container Is formed of a resin having a loss factor (ε · tan δ) of 0.001 or less, a softening point temperature of 100 ° C. or more, and a height of 3.5 mm. It has been proposed to use a microwave oven container provided with the above spark prevention member, wherein the cross-sectional area of the spark prevention member is 1% or more and 20 mm ² or more with respect to the container bottom area. . A spark prevention member with the above features is provided, and the flange end of the container is covered with an exterior body so that the end of the metal layer is not exposed, thereby preventing the occurrence of sparks during heating in a microwave oven. It is described in Patent Document 1 that this can be done.

JP 2006-131270 A

  However, although the container described in Patent Document 1 is a container including a metal layer, although the metal layer is not exposed, when the container is heated in a microwave oven, electromagnetic waves are shielded by the presence of the metal layer. The electromagnetic wave irradiation to the food contained in the container is made only from the opening of the container (usually the opening at the upper end of the container), the heating efficiency of the food is low, and the heating temperature of the food tends to be uneven ( There is a concern that unevenness in the heating temperature is likely to occur partially in foods), and that foods containing liquid substances may cause bumping due to uneven heating.

  Moreover, in the container of patent document 1, since the metal layer in a container has large heat conductivity, since it is easy to convey the temperature (heat amount) of the food heated with the microwave oven to the outer surface of a container, and a container becomes high temperature. There was a problem that it was difficult to hold by hand when taking out the container after heating in the microwave.

  Furthermore, the container described in Patent Document 1 may expose a part of the metal layer due to contact with other articles, external impact, or the like. When heated in a microwave, sparks are generated.

  The present invention has been made in view of such a technical background, and is excellent in gas barrier properties as a container and can protect food from oxygen and moisture. On the other hand, when heating in a microwave oven, An object of the present invention is to provide a food container and a method for producing the same, which can prevent the occurrence of the problem, the container does not easily become high temperature, has high heating efficiency of food, and hardly causes unevenness in heating of the food.

  In order to achieve the above object, the present invention provides the following means.

[1] A step of preparing a resin-made inner container not containing a metal layer and a molding sheet containing at least a metal layer;
Forming the outer container by drawing the sheet for molding, and simultaneously superimposing the outer container on the outer surface of the inner container to detachably integrate the two containers.
The outer diameter of the opening of the inner container before the drawn drawing prepared is “X”, and the inner diameter of the opening of the die of the drawing mold used for drawing the outer container is “Y”. When
X ≧ Y
The manufacturing method of the container for foodstuffs characterized by these relational expressions being materialized.

[2] 0 mm ≦ (XY) ≦ 10 mm
2. The method for producing a food container as described in 1 above, wherein

[3] 0.5 mm ≦ (XY) ≦ 4.0 mm
2. The method for producing a food container as described in 1 above, wherein

[4] a resin-made inner container that does not contain a metal layer;
An outer container containing at least a metal layer,
The outer container is superimposed on the outer surface of the inner container, and the two containers are integrated in a separable manner,
When both the integrated containers are separated, the outer diameter of the opening of the separated inner container is “E”, and the inner diameter of the opening of the separated outer container is “F” ,
E ≧ F
A food container characterized by satisfying the following relational expression:

[5] 0 mm ≦ (E−F) ≦ 10 mm
5. The food container as described in 4 above, wherein

[6] A fourth flange portion extends from the peripheral edge of the opening at the upper end of the outer container toward the outer side in the horizontal direction, and a step portion extends substantially upward from the outer peripheral edge of the fourth flange portion. The fifth flange portion is extended from the upper end of the step portion toward the outside in the horizontal direction,
A sixth flange portion extends from the periphery of the opening at the upper end of the inner container toward the outer side in the horizontal direction, and the lower surface of the sixth flange portion is in contact with the upper surface of the fourth flange portion of the outer container. 6. The food container according to item 4 or 5 above, wherein the end edges of the sixth flange portions are in contact with the inner peripheral surface of the step portion of the outer container.

  [7] The food container according to [6], wherein the constituent members of the inner container are not stacked on at least the outer peripheral edge of the upper surface of the fifth flange portion of the outer container.

[8] A first flange portion extends from the periphery of the opening at the upper end of the inner container toward the outer side in the horizontal direction, and a step portion extends substantially downward from the outer periphery of the first flange portion. The second flange portion extends from the lower end of the step portion toward the outside in the horizontal direction,
A third flange portion extends from the peripheral edge of the opening at the upper end of the outer container toward the outer side in the horizontal direction, and the upper surface of the third flange portion is in contact with the lower surface of the first flange portion of the inner container. 6. The food container according to item 4 or 5, wherein the food container is laminated, and a tip edge of the third flange portion is in contact with an inner peripheral surface of a step portion of the inner container.

  [9] The food container according to item 8 above, wherein the constituent members of the outer container are not stacked on at least the outer peripheral edge of the lower surface of the second flange portion of the inner container.

[10] The material of the outer surface of the inner container is polypropylene or crystalline polyethylene terephthalate,
10. The food container according to any one of 4 to 9 above, wherein the material of the inner surface of the outer container is polypropylene, polyethylene, nylon, epoxy resin, epoxy melamine resin, acrylic resin, urethane resin, vinyl acetate resin, or aluminum. .

  [11] The two containers are used in an integrated state until microwave heating is performed. When the microwave heating is performed, the containers are separated and only the inner container is used for microwave heating. 11. The food container according to any one of items 4 to 10 above.

[12] A step of filling a food in the inner container of the integrated food container according to any one of 4 to 11,
Bonding a lid to the inner container and sealing the opening of the inner container;
And a step of heat sterilizing the sealed food container. A method for producing a double container filled with food,

  According to the inventions [1] and [2], by using drawing, the outer container containing the metal layer is superimposed on the outer surface of the resin inner container not containing the metal layer, and the two containers are separated. An integrated food container can be produced. At this time, the outer diameter of the opening of the inner container before the prepared drawing is set to “X”, and the inner diameter of the opening of the die of the drawing mold used for drawing the outer container is set to “Y”. ", The production is carried out in such a manner that the relational expression of X ≧ Y is satisfied, so that the food container in which the inner container and the outer container are integrated with sufficient integrated strength can be manufactured. Therefore, the obtained food container can sufficiently prevent the two containers from being separated during storage, food filling, and the like. On the other hand, after the heat treatment for sterilization of the food container, the inner container integrated with sufficient integrated strength due to the difference in heat shrinkage between the inner container and the outer container at the time of subsequent cooling Since the integrated strength of the outer container is reduced, the inner container and the outer container can be easily separated by a human hand after the heat sterilization treatment.

  And in the state which preserve | saved the said container for foods with which the food was filled, when an outer side container contains a metal layer, it is excellent in the gas barrier property as a container, and can protect food from oxygen and a water | moisture content. .

  On the other hand, when the food in the food container filled with food is heated in a microwave oven (because heat sterilization has already been performed), the inner and outer containers can be easily handled by human hands. The inner container filled with food can be put into a microwave oven and heated, and the inner container does not contain a metal layer, so it is heated in the microwave oven. In this case, it is possible to prevent the occurrence of sparks, and the effect that the container is not easily heated to high temperature, the heating efficiency of the food is high, and unevenness in the heating of the food is hardly generated.

  According to the invention of [3], since the production is performed in such a manner that the relational expression of 0.5 mm ≦ (XY) ≦ 4.0 mm is established, the integrated strength of the inner container and the outer container can be further increased. It is possible to stabilize the state in which both containers are integrated.

  The inventions [4] and [5] (food containers) define the characteristics of the food containers obtained by the production method according to any one of the above [1] to [3]. Is a configuration in which an outer container containing a metal layer is superimposed on an outer surface of a resin-made inner container that does not contain a metal layer, and the two containers are integrated in a separable manner. When the container is separated, the outer diameter of the opening of the inner container in the separated state is “E”, and the inner diameter of the opening of the outer container in the separated state is “F”. Is established. In the food container having such a configuration, the inner container and the outer container are integrated with sufficient integrated strength.

  And in the state which preserve | saves the food container of this invention with which food was filled, the outer container contains a metal layer, and is excellent in the gas barrier property as a container, and protects food from oxygen and moisture. Can do.

  On the other hand, when the food in the food container filled with food is heated in a microwave oven (because heat sterilization has already been performed), the inner and outer containers can be easily handled by human hands. The inner container filled with food can be put into a microwave oven and heated, and the inner container does not contain a metal layer, so it is heated in the microwave oven. In this case, it is possible to prevent the occurrence of sparks, and the effect that the container is not easily heated to high temperature, the heating efficiency of the food is high, and unevenness in the heating of the food is hardly generated.

  In the invention of [6], the integrated strength of the inner container and the outer container can be further increased, and the state where both containers are integrated can be further stabilized.

  In the invention of [7], since the component of the inner container is not laminated on at least the outer peripheral edge of the upper surface of the fifth flange of the outer container, that is, the fifth flange of the outer container And since it is the structure which protruded outward from the structural member (6th flange part etc.) of an inner side container, the isolation | separation operation | work of an inner side container and an outer side container can be performed smoothly.

  In the invention of [8], the integrated strength of the inner container and the outer container can be further increased, and the state where both containers are integrated can be further stabilized.

  In the invention of [9], since the component of the outer container is not laminated on at least the outer peripheral edge of the lower surface of the second flange of the inner container, that is, the second flange of the inner container is And since it is the structure which protruded outward from the structural member (3rd flange part etc.) of an outer side container, the isolation | separation operation | work of an inner side container and an outer side container can be performed smoothly.

  In the invention of [10], since the material of the outer surface of the inner container and the material of the inner surface of the outer container are limited to specific materials, the inner container can retain its shape even in a separated state and has excellent heat resistance. Thus, even when heated in a microwave oven, the shape is sufficiently retained, and both containers are integrated in a sufficiently separable state.

  In the invention of [11], since the two containers are used in an integrated state until the microwave heating is performed, the outer container contains a metal layer until the microwave heating is performed. Therefore, it is excellent in gas barrier properties as a container and can protect food from oxygen and moisture. On the other hand, when performing microwave heating, both containers are separated, and only the inner container that does not contain a metal layer is used for microwave heating. Generation can be prevented, the container is unlikely to become high temperature, food heating efficiency is high, and uneven heating is unlikely to occur.

  In the invention of [12], a heat treatment for sterilization (for example, retort sterilization, boil sterilization, etc.) is performed on the food container after filling and sealing with food. When the food container is cooled, heat shrinkage occurs. At this time, the outer container has a metal layer, so the heat shrinkage is small, whereas the inner container is a resin container that does not contain a metal layer. The heat shrinkage is large, and the difference in heat shrinkage reduces the integrated strength of the inner and outer containers that have been integrated with sufficient integrated strength. The inner container and the outer container can be easily separated by a human hand.

  That is, if the food container of the present invention is used, the period from when the food container is manufactured to when the food is filled in the inner container of the food container and the heat sterilization process is completed after the opening is sealed. Is sufficient to prevent the inner and outer containers from being integrated with sufficient integration strength so that both containers are separated from each other. When performing range heating, the inner container and the outer container can be easily separated by a human hand.

BRIEF DESCRIPTION OF THE DRAWINGS It is sectional drawing which shows the manufacturing method of the food container which concerns on this invention in order of a process, (A) is the state which set the sheet | seat for shaping | molding and the inner container to the drawing apparatus, (B) is performing drawing. An intermediate state, (C) shows a state after drawing. (A) is a bottom view of the drawing mold, (B) is a bottom view of the inner container before the prepared drawing (top view of the inner container in the arrangement state of FIG. 1 (A)). It is. It is sectional drawing which shows an example of the container for foodstuffs obtained with the manufacturing method of this invention. It is sectional drawing which shows the state which isolate | separated the food container of FIG. 3 into the inner side container and the outer side container. It is sectional drawing which shows the other example of the container for foods obtained with the manufacturing method of this invention. It is sectional drawing which shows the state which isolate | separated the food container of FIG. 5 into the inner side container and the outer side container.

  A method for producing a food container according to the present invention will be described with reference to FIG. In FIG. 1, 81 is a bottom rib pressing die, and the molding surface thereof is formed in a shape that matches the shape of the bottom surface of the outer container 3 of FIG. 82 is a die. Reference numeral 83 denotes a punch, which is fixed on the punch base 84. Reference numeral 85 denotes a support portion (wrinkle pressing portion) that sandwiches the forming sheet 80 between the dice 82 and the wrinkle restraining surface 82a, and is configured to move up and down. The bottom rib pressing die 81, the die (female die) 82, the punch (male die) 83, the punch base 84, and the support portion (wrinkle pressing portion) 85 constitute a drawing mold.

  Thus, as shown in FIG. 1A, the inner container 2 is set on the punch 83. At this time, the inner wall 2 is set on the outer side of the punch 83 from the upper side in such a manner that the bottom wall 2a of the inner container 2 is set upward and the opening 20 is set downward. The inner container 2 is manufactured by vacuum molding or injection molding. Next, the molding sheet 80 containing the metal layer 52 is placed on the support part (wrinkle pressing part) 85 and the inner container 2. Next, as shown in FIG. 1B, the die 82 is moved downward, and the molding sheet 80 having a circular shape in plan view is formed by the upper surface of the support portion (wrinkle pressing portion) 85 and the wrinkle restraining surface 82a of the die 82. Then, the die 82 is further moved downward. Next, as shown in FIG. 1 (C), the wrinkle restraining surface 82a is further moved downward until it comes into contact with the upper surface of the support portion (wrinkle restraining portion) 85, and the bottom rib pressing die 81 is also moved downward, thereby forming the molding. The food container 1 shown in FIG. 3 is obtained by drawing the sheet 80 and superposing the outer container 3 on the outer surface of the inner container 2 while forming the outer container 3 containing the metal layer by drawing. be able to. That is, the outer container 3 containing a metal layer is superimposed on the outer surface of a resin-made inner container 2 that does not contain a metal layer, thereby producing a food container 1 in which the containers 2 and 3 are detachably integrated. Can do.

In the manufacturing method of the present invention, the outer diameter of the opening 20 of the inner container 2 before the prepared drawing is set to “X” (mm), and the die 82 used when the outer container 3 is drawn. When the inner diameter of the opening is “Y” (mm) (see FIG. 1A and FIG. 2),
X ≧ Y
It is important to perform drawing in such a manner that the above relational expression holds. By performing the drawing in such a manner that the relational expression is established, the food container 1 in which the inner container 2 and the outer container 3 are integrated with sufficient integrated strength can be manufactured.

  (XY) is preferably set in a range of 0 mm to 10 mm. Among these, (XY) is more preferably set in the range of 0.5 mm or more and 4.0 mm or less.

  The manufacturing method of the present invention is manufactured using drawing, and heating is not performed in the molding process. Therefore, the material of the inner surface of the outer container 3 (on the side in contact with the inner container 2 in the molding sheet 80). The material of the surface) may be the same as or different from the material of the outer surface of the inner container 2.

  A food container 1 obtained by the production method of the present invention includes a resin-made inner container 2 that does not have a metal layer, and an outer container 3 that has at least a metal layer 52. The container 3 is overlapped and the both containers 2 and 3 are laminated and integrated so as to be separable.

  And since it was manufactured with the said manufacturing method, in this food container 1, it has the structure where the following relational expressions are materialized.

That is, when the two integrated containers (the stage where the heat sterilization process described later is not performed) are separated, the outer diameter of the opening 20 of the inner container 2 in the separated state is set to “E”. When the inner diameter of the opening 30 of the outer container 3 in the separated state is “F” (see FIG. 4),
E ≧ F
The relational expression is established.

  One embodiment of the food container 1 obtained by the production method of the present invention is shown in FIG. The inner container 2 includes a bottom wall 2a and a peripheral side wall 2b raised upward from the periphery of the bottom wall 2a, and an opening 20 is provided at the upper end of the peripheral side wall 2b. The outer container 3 includes a bottom wall 3a and a peripheral side wall 3b raised upward from the periphery of the bottom wall 3a, and an opening 30 is provided at the upper end of the peripheral side wall 3b. In the present embodiment, the bottom wall 2a of the inner container 2 has a circular shape in plan view, and the peripheral side wall 2b of the inner container 2 has a substantially cylindrical shape. In the present embodiment, the bottom wall 3a of the outer container 3 has a circular shape in plan view, and the peripheral side wall 3b of the outer container 3 has a substantially cylindrical shape.

  A fourth flange portion 34 extends from the peripheral edge of the opening 30 at the upper end of the outer container 3 (the upper end of the peripheral side wall 3b) outward in the horizontal direction, and the outer peripheral edge of the fourth flange portion 34 A step portion 36 extends substantially upward from the top, and a fifth flange portion 35 extends from the upper end of the step portion 36 outward in the horizontal direction (see FIG. 3).

  A sixth flange portion 26 extends from the periphery of the opening 20 at the upper end of the inner container 2 (the upper end of the peripheral side wall 2b) outward in the horizontal direction (see FIG. 3).

  In the present embodiment, the inner container 2 is an inner container formed of a single resin layer (single layer), and the outer container 3 has a first resin layer (inner layer) on one surface of the metal layer 52. ) 51 is laminated, and the second resin layer (outer layer) 53 is laminated on the other surface of the metal layer 52 (see FIG. 3).

  Thus, the outer container 3 is overlapped on the outer surface of the inner container 2, and the two containers 2 and 3 are integrated in a separable manner. That is, the inner surface of the bottom wall 3a of the outer container 3 is in contact with the outer surface of the bottom wall 2a of the inner container 2, and the outer surface of the peripheral wall 2b of the inner container 2 is placed on the outer surface of the peripheral wall 3b of the outer container 3. The inner surface is disposed in contact with the inner surface, the lower surface of the sixth flange portion 26 of the inner container 2 is disposed in contact with the upper surface of the fourth flange portion 34 of the outer container 3, and the tip edge of the sixth flange portion 26 is disposed. The outer container 3 is disposed in contact with the inner peripheral surface of the step portion 36 of the outer container 3, and the outer container 3 is superimposed on the outer surface of the inner container 2 in a substantially conforming state so that the containers 2, 3 can be separated. They are integrated (see FIG. 3).

  Further, the constituent members of the inner container 2 are not laminated on the upper surface of the fifth flange portion 35 of the outer container 3. In other words, the fifth flange portion 35 of the outer container 3 protrudes outward from the constituent members of the inner container 2 (such as the sixth flange portion 26). With such a configuration, the inner container 2 and the outer container 3 are formed. Separation work when separating can be performed smoothly. For example, when the fifth flange portion 35 of the outer container 3 protruding outward is held by hand and the fifth flange portion 35 is deformed, air enters between the inner container 2 and the outer container 3, The integrated inner container 2 and outer container 3 can be separated.

And since this food container 1 in FIG. 3 is manufactured by the manufacturing method of the present invention, the two integrated containers (the one before the heat sterilization process described later) are separated. When the outer diameter of the opening 20 of the inner container 2 in the separated state is “E” and the inner diameter of the opening 30 of the outer container 3 in the separated state is “F” (see FIG. 4),
E ≧ F
The relational expression is established.

  In the food container having such a relational expression, the inner container 2 and the outer container 3 are integrated with sufficient integrated strength. Therefore, the obtained food container 1 can sufficiently prevent the integrated containers 2 and 3 from being separated during storage, food filling, etc. (excellent in separation prevention). On the other hand, after the heat treatment for sterilization is performed on the food container, the inner container 2 that has been integrated with sufficient integrated strength due to the difference in thermal shrinkage between the inner container and the outer container at the time of subsequent cooling. Since the integrated strength of the outer container 3 is reduced, the inner container 2 and the outer container 3 can be easily separated by a human hand after the heat sterilization treatment.

  In the food container 1 having the above-described configuration, the inner container 2 and the outer container 3 are used in an integrated state until the microwave oven is heated during storage. At this time, the outer container 3 is made of metal. Since the layer 52 is contained, the food container 1 has excellent gas barrier properties and can protect food from oxygen and moisture.

  On the other hand, when the food in the food container filled with food is heated in a microwave oven (because the heat sterilization process has already been performed), the inner container 2 and the outer container 3 are held by human hands. Can be easily separated, and only the inner container 2 filled with food can be heated in a microwave oven (see FIG. 4). At this time, the inner container 2 does not contain a metal layer. Since it is a structure, when it heats with a microwave oven, while being able to prevent generation | occurrence | production of a spark, the container 2 is hard to become high temperature, the heating efficiency of food is high, and the effect that a nonuniformity does not arise in the heating of food is acquired.

   Another embodiment of the food container 1 obtained by the production method of the present invention is shown in FIG. The inner container 2 includes a bottom wall 2a and a peripheral side wall 2b raised upward from the periphery of the bottom wall 2a, and an opening 20 is provided at the upper end of the peripheral side wall 2b. The outer container 3 includes a bottom wall 3a and a peripheral side wall 3b raised upward from the periphery of the bottom wall 3a, and an opening 30 is provided at the upper end of the peripheral side wall 3b. In the present embodiment, the bottom wall 2a of the inner container 2 has a circular shape in plan view, and the peripheral side wall 2b of the inner container 2 has a substantially cylindrical shape. In the present embodiment, the bottom wall 3a of the outer container 3 has a circular shape in plan view, and the peripheral side wall 3b of the outer container 3 has a substantially cylindrical shape.

  A first flange portion 21 extends outward from the peripheral edge of the opening 20 at the upper end of the inner container 2 (the upper end of the peripheral side wall 2b) in the horizontal direction, and the outer peripheral edge of the first flange portion 21. A step portion 23 extends substantially downward from the bottom, and a second flange portion 22 extends from the lower end of the step portion 23 outward in the horizontal direction (see FIG. 5).

  A third flange portion 33 extends from the periphery of the opening 30 at the upper end of the outer container 3 (the upper end of the peripheral side wall 3b) outward in the horizontal direction (see FIG. 5).

  In the present embodiment, the inner container 2 is an inner container formed of a single resin layer (single layer), and the outer container 3 has a first resin layer (inner layer) on one surface of the metal layer 52. ) 51 is laminated, and the second resin layer (outer layer) 53 is laminated on the other surface of the metal layer 52 (see FIG. 5).

  Thus, the outer container 3 is overlapped on the outer surface of the inner container 2, and the two containers 2 and 3 are integrated in a separable manner. That is, the inner surface of the bottom wall 3a of the outer container 3 is in contact with the outer surface of the bottom wall 2a of the inner container 2, and the outer surface of the peripheral wall 2b of the inner container 2 is placed on the outer surface of the peripheral wall 3b of the outer container 3. The inner surface is disposed in contact with the upper surface, the upper surface of the third flange portion 33 of the outer container 3 is disposed in contact with the lower surface of the first flange portion 21 of the inner container 2, and the tip edge of the third flange portion 33 is disposed. The outer container 3 is disposed in contact with the inner peripheral surface of the step portion 23 of the inner container 2, and the outer container 3 is superimposed on the outer surface of the inner container 2 so as to be separable. They are integrated (see FIG. 5).

  Further, the constituent members of the outer container 3 are not laminated on the lower surface of the second flange portion 22 of the inner container 2. That is, the 2nd flange part 22 of the inner side container 2 is the structure which protruded outward from the structural member (3rd flange part 33 etc.) of the outer side container 3, By such a structure, the inner side container 2 and the outer side container 3 are comprised. Separation work when separating can be performed smoothly. For example, when the second flange portion 22 of the inner container 2 protruding outward is held by hand and the second flange portion 22 is deformed, air enters between the inner container 2 and the outer container 3, The integrated inner container 2 and outer container 3 can be separated.

And since this food container 1 of FIG. 5 is manufactured by the manufacturing method of the present invention, the two integrated containers (the one before the heat sterilization process described later) are separated. When the outer diameter of the opening 20 of the inner container 2 in the separated state is “E” and the inner diameter of the opening 30 of the outer container 3 in the separated state is “F” (see FIG. 6),
E ≧ F
The relational expression is established.

  In the food container having such a relational expression, the inner container 2 and the outer container 3 are integrated with sufficient integrated strength. Therefore, the obtained food container 1 can sufficiently prevent the integrated containers 2 and 3 from being separated during storage, food filling, etc. (excellent in separation prevention). On the other hand, after the heat treatment for sterilization of the food container, the inner side integrated with sufficient integration strength due to the difference in thermal shrinkage between the inner container 2 and the outer container 3 at the time of subsequent cooling. Since the integrated strength of the container 2 and the outer container 3 is reduced, the inner container 2 and the outer container 3 can be easily separated by a human hand after the heat sterilization treatment.

  In the food container 1 having the above-described configuration, the inner container 2 and the outer container 3 are used in an integrated state until the microwave oven is heated during storage. At this time, the outer container 3 is made of metal. Since the layer 52 is contained, the food container 1 has excellent gas barrier properties and can protect food from oxygen and moisture.

  On the other hand, when the food in the food container filled with food is heated in a microwave oven (because the heat sterilization process has already been performed), the inner container 2 and the outer container 3 are held by human hands. Can be easily separated (see FIG. 6), and only the inner container 2 filled with food can be put into a microwave oven and heated, and the inner container 2 does not contain a metal layer. Since it is a structure, when it heats with a microwave oven, while being able to prevent generation | occurrence | production of a spark, the container 2 is hard to become high temperature, the heating efficiency of food is high, and the effect that a nonuniformity does not arise in the heating of food is acquired.

  In the present invention, the thickness of the inner container 2 is preferably set to 0.5 mm to 1.0 mm. The inner container 2 is not particularly limited as long as it is a resin container that does not include a metal layer. The inner container 2 may be composed of a single layer (single resin layer) or a plurality of layers (a plurality of types of resin layers). (Laminate). Among these, a polypropylene inner container and a polyethylene terephthalate inner container are preferable because they have good heat resistance.

  The thickness of the outer container 3 is preferably thin considering the cost, but is determined by the rigidity required for the food container after the food is filled. The thickness of the outer container 3 is preferably set to 0.05 mm to 0.5 mm. The outer container 3 may be composed of a single layer consisting of only the metal layer 52 or may be composed of a multilayer (laminated body) including at least the metal layer 52. As the outer container 3 having the laminated structure, for example, three layers in which a first resin layer 51 is laminated on one surface of a metal layer 52 and a second resin layer 53 is laminated on the other surface of the metal layer 52. The outer container 3 having the configuration can be exemplified (see FIGS. 3 and 5). When the outer container 3 requires a large rigidity, for example, a configuration such as CPP (30 μm) / AL (120 μm) / CPP (200 μm), CPP (50 μm) / AL (100 μm), etc. (laminated configuration and each layer) In the case where large rigidity is not required, for example, CPP (30 μm) / AL (40 μm) / Ny (25 μm), PET (25 μm) / AL (60 μm) / PE (30 μm) And the like (stacked configuration and thickness of each layer) can be illustrated.

  The metal constituting the metal layer 52 is not particularly limited. For example, in addition to single metals such as aluminum, iron, copper, silver, and tantalum, alloys of these metals, magnesium alloys, titanium alloys, etc. Is mentioned. Among these, the metal layer 52 is preferably formed of an aluminum layer from the viewpoint of cost. Although it does not specifically limit as aluminum, Pure aluminum type alloy or 8000 type alloy can be used.

  Table 1 shows preferred examples of combinations of the material of the inner container 2 and the material of the outer container 3. In the configuration example of the outer container, the material described on the left side is a material that becomes the inner surface (the surface in contact with the inner container) in the case of a laminated configuration.

  In addition, the following abbreviations described in this specification including Tables 1 and 2 mean the following materials (layers), respectively.

“PP”: Polypropylene “C-PET”: Crystalline polyethylene terephthalate “CPP”: Unstretched polypropylene (film)
"AL": Aluminum (foil)
“Fe”: Iron “PE”: Polyethylene “Ny”: Nylon “Resin Coat”: A resin layer formed by applying a resin, the resin types being epoxy resin, epoxy melamine resin, acrylic resin, urethane Resin, vinyl acetate resin, vinyl chloride-vinyl acetate copolymer resin, and the like. A resin coating layer is formed by coating a resin obtained by dissolving such a resin in a solvent.

  In the present invention, as an auxiliary structure for further improving the prevention of separation between the inner container 2 and the outer container 3, for example, the bottom wall 2a of the inner container 2 and the bottom wall 3a of the outer container 3 are adhered with an adhesive. You may employ | adopt the structure currently made.

  The shape of the food container 1 of the present invention is not particularly limited to the shape of the above embodiment, and is not particularly limited as long as it is a shape that can accommodate food. In addition, the plan view shape (top view shape) of the food container 1 is not particularly limited. For example, a perfect circle shape, an ellipse shape, a square shape (a square shape, a rhombus shape, a rectangular shape, etc.), A regular pentagon shape, other regular polygon shapes, etc. are mentioned.

  Moreover, the food container 1 of the present invention is not particularly limited to the one manufactured by the above-exemplified manufacturing method, and the manufacturing method is merely an example.

  The food container 1 of the present invention is supplied to consumers as a final product (product) through the following filling process, sealing process, heat sterilization process, and the like. That is, after filling the inner container 2 of the food container 1 in an integrated state with food (liquid or solid food), the flange portions (first flange portion 21, sixth flange portion 26, etc.) of the inner container 2 are provided. ) To seal the opening 20 of the inner container 2 by sealing the peripheral edge of the lid. Thereafter, the sealed food container is heat sterilized. The heating temperature is generally set to 80 ° C to 130 ° C. The time for the heat sterilization treatment is generally 10 minutes to 1.5 hours. The lid is not particularly limited, and examples thereof include a laminated film having a laminated structure such as PET / AL / PET / sealant or PET / AL / PET / heat seal lacquer.

  In the food container after the heat sterilization treatment (the food is filled in the inner container), the food container is heated and then cooled to cause heat shrinkage. At this time, the outer container has a metal layer. However, the inner container is a resin container that does not contain a metal layer, so it has a relatively large heat shrinkage. Therefore, when the microwave oven heating is performed, the inner container 2 and the outer container 3 can be easily separated by a human hand.

  That is, if the food container 1 obtained by the production method of the present invention is used, after the food container is manufactured, the food is filled in the inner container of the food container and the opening is sealed and heat sterilized. Until the end of the process (until the end of the heat sterilization process that is required not to be separated), the inner container 2 and the outer container 3 are integrated with sufficient integrated strength, and the two containers are separated. On the other hand, after filling with food and performing a heat sterilization treatment, the inner container 2 and the outer container 3 can be easily separated by human hands when performing microwave heating.

In addition, as mentioned above, heat shrinkage occurs in the food container through the heat sterilization treatment and subsequent cooling. At this time, the shrinkage rate of the inner container (resin container not containing the metal layer) is 0. Since it is 5% to 3% (0.8% to 1.8% made of PP), the outer diameter of the opening of the inner container (separated state) after heat sterilization treatment and cooling is set to “M”, When the outer diameter of the opening of the inner container (separated state) before the heat sterilization treatment is “E”,
(EM) /E=0.005 to 0.03
From this relational expression, the outer diameter E of the opening of the inner container (separated state) before the heat sterilization treatment is obtained by the following equation:
E = (M / 0.995) to (M / 0.97)
Therefore, if the outer diameter M of the opening of the inner container (separated state) after the heat sterilization treatment and cooling is measured, the outer diameter E of the opening of the inner container (separated state) before the heat sterilization treatment can be calculated. it can.

Similarly, heat shrinkage occurs in the food container through the heat sterilization treatment and subsequent cooling. At this time, the shrinkage rate of the outer container (having the metal layer) is 0.1. Since the inner diameter of the opening of the outer container (separated state) after heat sterilization treatment and cooling is “K”, the inner diameter of the opening of the outer container (separated state) before the heat sterilization treatment is “F”
(F−K) /F=0.001 to 0.01
From this relational expression, the inner diameter F of the opening of the outer container (separated state) before the heat sterilization treatment is obtained by the following equation:
F = (K / 0.999) to (K / 0.99)
Therefore, by measuring the inner diameter K of the opening of the outer container (separated state) after the heat sterilization process and cooling, the inner diameter F of the opening of the outer container (separated state) before the heat sterilization process can be calculated.

  Thus, if the outer diameter M of the opening part of the inner container (separated state) after the heat sterilization process and cooling is measured, the outer diameter E of the opening part of the inner container (separated state) before the heat sterilization process is calculated. In addition, if the inner diameter K of the opening of the outer container (separated state) after the heat sterilization process and cooling is measured, the inner diameter F of the opening of the outer container (separated state) before the heat sterilization process can be calculated. From the food container after sterilization treatment and cooling, when the food container is in the state before the heat sterilization treatment, the constituent requirements of the inventions [4] and [5] (numerical values of E, numerical values of F, (E− It is possible to determine whether or not the value of F) was provided.

  In the present invention, when obtaining the above-mentioned “X”, “E”, “F”, “M”, “K”, the plan view shape (top view shape) of the food container 1 is a perfect circle. In some cases, X, E, F, M, and K in a state where the container is in a perfect circle shape, respectively. In addition, the same applies when the shape of the food container 1 in plan view (top view shape) is an elliptical shape, a quadrangular shape (a square shape, a rhombus shape, a rectangular shape, etc.), a regular pentagon shape, and other regular polygonal shapes. And That is, “X”, “E”, “F”, “M”, and “K” described above do not mean values measured in a shape distorted from a normal plan view shape.

  In addition, when the planar view shape (top view shape) of the food container 1 is an elliptical shape, a quadrangular shape (a square shape, a rhombus shape, a rectangular shape, etc.), a regular pentagonal shape, or any other regular polygonal shape, The above-mentioned “X”, “Y”, “E”, “F”, “M”, “K” all mean the longest inner diameter. That is, for example, when the shape in plan view is a square shape, the “inner diameter” means an inner diameter on a square diagonal line.

  Next, specific examples of the present invention will be described, but the present invention is not particularly limited to these examples.

<Example 1>
The food container 1 shown in FIG. 3 was manufactured by carrying out the manufacturing method (see FIG. 1) of the present invention described in the previous section. As the molding sheet 80, an outer container sheet composed of a three-layer laminate of unstretched polypropylene film layer (inner layer) (30 μm) / aluminum layer (120 μm) / unstretched polypropylene film layer (outer layer) (200 μm) is used. As the inner container 2, an inner container made of polypropylene having a thickness of 0.5 mm is used, and the outer container 3 is formed simultaneously by forming the outer container 3 by drawing the forming sheet 80. By superposing the outer container 3 on the outer surface, the outer container 3 having a thickness of 350 μm is superimposed on the outer surface of the inner container 2 having a thickness of 0.5 mm, thereby producing the food container 1 in which both the containers 2 and 3 are detachably integrated. did. The outer diameter X of the opening of the inner container before the prepared drawing is 63.4 mm, and the diameter of the opening of the die 82 of the drawing mold used when the outer container is drawn. The (inner diameter) Y was 63.4 mm, and therefore the value of (XY) was 0.0 mm.

<Example 2>
FIG. 3 is the same as in Example 1 except that the outer diameter X of the opening of the inner container before the drawn drawing is changed and the value of (XY) is set to 0.5 mm. The food container 1 shown was manufactured.

<Example 3>
FIG. 3 shows the same procedure as in Example 1 except that the outer diameter X of the opening of the inner container before the drawn drawing is changed and the value of (XY) is set to 1.0 mm. The food container 1 shown was manufactured.

<Example 4>
FIG. 3 is the same as in Example 1 except that the outer diameter X of the opening of the inner container before the drawn drawing is changed and the value of (XY) is set to 2.0 mm. The food container 1 shown was manufactured.

<Example 5>
FIG. 3 is the same as in Example 1 except that the outer diameter X of the opening of the inner container before the drawn drawing is changed and the value of (XY) is set to 3.0 mm. The food container 1 shown was manufactured.

<Example 6>
FIG. 3 is the same as in Example 1 except that the outer diameter X of the opening of the inner container before the drawn drawing is changed and the value of (XY) is set to 4.0 mm. The food container 1 shown was manufactured.

<Example 7>
FIG. 3 is the same as in Example 1 except that the outer diameter X of the opening of the inner container before the drawn drawing is changed and the value of (XY) is set to 5.0 mm. The food container 1 shown was manufactured.

<Comparative Example 1>
The same as in Example 1 except that the outer diameter X of the opening of the inner container before the prepared drawing was changed and the value of (XY) was set to “−1.0 mm”. A food container was manufactured.

  Each food container obtained as described above was evaluated based on the following “formability evaluation method”, “adhesion evaluation method”, and “separation prevention evaluation method before heat sterilization treatment”. The obtained food containers were subjected to heat treatment at a temperature corresponding to the heat sterilization treatment and evaluated based on the following “Evaluation Method for Easiness of Separation after Heat Sterilization Treatment”. These results are shown in Table 2.

<Formability evaluation method>
The inner and outer containers of the obtained food container were broken and did not have wrinkles and were excellent in moldability, “○”, and when the container depth was shallow, there were no breaks or wrinkles, but the depth of the container In the case of deep, the case where breakage or wrinkle was rarely observed was designated as “Δ”, and the case where breakage or wrinkle was observed was designated as “x”.

<Adhesion evaluation method>
“○” indicates that the inner and outer containers are sufficiently integrated, “△” indicates that the inner and outer containers are integrated, and “△” indicates that the inner and outer containers are integrated, and the integrated strength between the inner and outer containers Was insufficient.

<Evaluation method for separation prevention before heat sterilization>
Those that could be easily separated by human hands were marked with “×”, those that could not be separated without a slight force applied by human hands were “△”, and could not be separated unless a large force was applied with human hands. A thing (thing excellent in separation prevention property) was set as "(circle)".

<Evaluation method for ease of separation after heat sterilization>
The obtained food container was placed in a constant temperature bath at 100 ° C. for 10 minutes, then taken out and allowed to cool naturally in a room at 25 ° C., and the separation of the food container was evaluated by human hands after 24 hours. . "○" indicates that it can be easily separated by human hands without requiring a large force, "△" indicates that it can be separated by human hands if a large force is used, and those that are difficult to separate by human hands Was marked “x”.

  As is apparent from Table 2, the food containers of Examples 1 to 7 of the present invention were excellent in moldability, were not broken, and were excellent in gas barrier properties as containers. In addition, the food containers of Examples 1 to 7 of the present invention can be sufficiently prevented from being separated until the heat sterilization treatment that is required not to be separated. The inner and outer containers could be easily separated by hand.

  In contrast, the food container of Comparative Example 1 can be easily separated before the heat sterilization treatment, and the inner container and the outer container may be separated during storage, food filling, and the like. There is sex.

  The food container of the present invention is not particularly limited. For example, the food container is filled with food such as liquid food such as soup and porridge, and solid food such as cooked fish and vegetables. Used as a container. When the food in the food container of the present invention filled with food is heated in a microwave oven, the inner container and the outer container are separated, and only the inner container filled with food is put into the microwave oven. Put in and heat.

DESCRIPTION OF SYMBOLS 1 ... Food container 2 ... Inner container 3 ... Outer container 20 ... Opening part 21 ... 1st flange part 22 ... 2nd flange part 23 ... Step part 26 ... 6th flange part 30 ... Opening part 33 ... 3rd flange part 34 ... Fourth flange portion 35 ... Fifth flange portion 36 ... Step portion 52 ... Metal layer 80 ... Forming sheet 82 ... Dies (female type)
83 ... Punch (male type)

Claims (3)

A step of preparing a resin-made inner container not containing a metal layer and a molding sheet containing at least a metal layer;
Forming the outer container by drawing the sheet for molding, and simultaneously superimposing the outer container on the outer surface of the inner container to detachably integrate the two containers.
The outer diameter of the opening of the inner container before the drawn drawing prepared is “X”, and the inner diameter of the opening of the die of the drawing mold used for drawing the outer container is “Y”. When
X ≧ Y
The manufacturing method of the container for foodstuffs characterized by these relational expressions being materialized. 0mm ≦ (XY) ≦ 10mm
The manufacturing method of the container for foodstuffs of Claim 1 with which these relational expressions are materialized. 0.5 mm ≦ (XY) ≦ 4.0 mm
The manufacturing method of the container for foodstuffs of Claim 1 with which these relational expressions are materialized.

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