JP7415189B2 - Method for manufacturing microwave containers - Google Patents

Description

The present invention relates to a microwave container.

Conventionally, various techniques have been proposed regarding containers for microwave ovens (for example, see Patent Document 1).

Patent Document 1 discloses a packaging container that includes a container body that stores contents and a lid made of a plastic material that closes an opening of the container body.

When this packaging container is heated in a microwave oven, the lid bulges outward due to an increase in the internal pressure of the packaging container, the lid peels off at the first convex portion, and the internal pressure escapes through the through hole. Therefore, in the packaging container, when cooking the contents such as food in a microwave oven, there is no need to make holes for steam to escape or to peel off part of the lid before cooking.

Japanese Patent Application Publication No. 2009-120247

In a microwave oven container, there are cases where it is desired to selectively peel off a specific portion of the heat-welded portion formed on the flange portion.

The present invention has been made in view of the above circumstances, and provides a method for manufacturing a microwave oven container in which a specific portion of a heat-welded portion formed on a flange portion can be selectively peeled off. be.

According to the present invention, the method for manufacturing a microwave oven container includes the step of thermally welding a lid material to a flange portion formed to extend outward from an opening of a container body, the thermal welding comprising: This is done by pressing the convex part of the seal head against the flange part through the lid material, and the convex part includes first and second parts connected to each other, and the height of the first part is equal to the height of the second part. , a method is provided.

In the present invention, since the height of the first part of the convex part of the seal head is lower than the height of the second part, the welding strength per unit width of the part pressed by the first part is lower than that of the part pressed by the second part. lower than the affected area. Therefore, a specific portion of the heat-welded portion formed on the flange portion can be selectively peeled off.

FIG. 1 is an exploded perspective view of a microwave oven container according to a first embodiment of the present invention. It is a top view of the container main body concerning a 1st embodiment. 2 is an enlarged view of part A in FIG. 1. FIG. 3 is a sectional view taken along line BB in FIG. 2. FIG. 3 is a sectional view taken along line CC in FIG. 2. FIG. It is an operational view of the microwave oven container according to the first embodiment, and is a diagram showing how steam is discharged. It is an operational view of the microwave oven container according to the first embodiment, and is a diagram showing how the lid material is peeled off. It is a top view of the container main body based on 2nd Embodiment of this invention. It is a top view of the container main body based on 3rd Embodiment of this invention. 9 is a sectional view taken along the line DD in FIG. 9. FIG. It is a top view of the container main body based on 4th Embodiment of this invention. 12 is a sectional view taken along line EE in FIG. 11. FIG. (a) is a bottom view of a seal head for forming a first heat welding part and a second heat welding part according to a fourth embodiment of the present invention, (b) is an enlarged view of part F in (a), (c) is a sectional view taken along line GG in (b).

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, modes for carrying out the present invention (hereinafter referred to as "embodiments") will be described in detail with reference to the accompanying drawings. The same elements are given the same numbers throughout the description of the embodiments.

(First embodiment)
First, the overall configuration of a microwave oven container according to a first embodiment will be described based on FIG. 1. As shown in FIG. 1, the main elements of the microwave container 10 include a container body 20 having an opening 21 and into which the contents 11 are filled, and a film-like lid material 50 that closes the opening 21. do. Both the container body 20 and the lid member 50 are made of resin material. Container body 2
The contents 11 stored in the container 0 are various kinds of foods, and can be of any type as long as they can be heated using a microwave oven.

The microwave container 10 also includes a flange portion 22 and a first heat welding portion 23A and a second heat welding portion 23B that are formed on the upper surface of the flange portion 22 and heat welded to the lid member 50. Be prepared. Furthermore, the microwave oven container 10 has a protrusion 24 that locks the lid 50 on the flange portion 2.
Prepare for 2.

Next, the configuration of each part of the microwave oven container 10 will be explained based on FIGS. 1 to 5. As shown in FIG. 2, the container body 20 has a housing portion 20b with a bottom 20a. The housing portion 20b, the bottom 20a, and the opening 21 have a substantially rectangular shape (in this example, substantially a square) with rounded corners in a plan view.

The flange portion 22 is formed to extend outward from the opening 21. Further, the flange portion 22 is a portion outside the inner portion (hereinafter referred to as “inner portion 22a”) where the first heat welding portion 23A and the second heat welding portion 23B are provided, and is a portion of the accommodating portion 20b. It has corner portions 22b at positions corresponding to each of the four corners. Each corner 22b is connected to the inner portion 22a via a step 22c, and is formed at a position one step lower than the inner portion 22a.

In addition, in anticipation of warpage during molding of the container body 20, the inner portion 22a may be inclined downward at an angle θ1 with respect to the horizontal plane H toward the extending end of the flange portion 22 (see FIG. 4).
. Such an inclination of the flange portion 22 can be formed substantially the same around the entire circumference of the flange portion 22.

Return to Figure 1. As shown in FIG. 1, the lid member 50 has an outer periphery that is approximately the same size as the outer periphery of the flange portion 22. As shown in FIG. After filling the storage part 20b with the contents 11, the lid material 50 is thermally welded (sealed) to the first heat welding part 23A and the second heat welding part 23B, thereby closing the opening 21 and closing the storage part. 20b is sealed.

As shown in FIG. 2, the first thermally welded portion 23A includes a rib on the entire circumference of the upper surface of the inner portion 22a of the flange portion 22, except for a steam exhaust portion 25 cut out for exhausting steam. It is formed into a shape and is thermally welded to the lid member 50. In this example, the steam exhaust portion 25 is provided near the inner side of one corner portion 22b of the flange portion 22.

The second thermally welded portion 23B is formed into a rib shape so as to form a recess 26 on the inner peripheral side of the first thermally welded portion 23A, and is thermally welded to the lid member 50. The second heat welding part 23B is the flange part 22
It is formed over the entire circumference of the upper surface of the inner portion 22a. The second thermally welded portion 23B is formed into a substantially rectangular shape (in this example, substantially square) so as to surround the opening 21 of the container body 20 on the upper surface of the inner portion 22a of the flange portion 22. Then, this second heat welding part 2
3B has a V-shaped portion 27 (easily peelable portion) extending outward at a position corresponding to the steam exhaust portion 25 (see FIG. 3).

As shown in FIG. 4, in this example, the second thermally welded portion 23B is formed so that its upper surface 23B1 is lower than the upper surface 23A1 of the first thermally welded portion 23A by a dimension h. As a result, when the seal bar (not shown) presses the lid member 50 from above against the first heat weld part 23A and the second heat weld part 23B, the seal bar presses against the second heat weld part 23B. Since the pressure is smaller than the pressing force of the seal bar against the first heat weld part 23A, the second heat weld part 23
The welding strength with the lid material 50 at B is lower than the welding strength with the lid material 50 at the first thermally welded portion 23A. As a result, the microwave container 10 is heated in the microwave, and the container 2
When the vapor pressure in 0b increases and reaches a predetermined pressure, the lid material 50 seals the sealing surface of the second thermal welding part 23B before the sealing surface (upper surface 23A1) of the first thermal welding part 23A. (Top surface 23B1
) peels off at any location. That is, in the first thermally welded portion 23A and the second thermally welded portion 23B, when the vapor pressure in the housing portion 20b reaches a predetermined pressure, the sealing performance between the first thermally welded portion 23A and the lid member 50 is reduced. is maintained, while the sealing performance between the second heat welded portion 23B and the lid member 50 is lost.

Note that by making the width of the second heat welding part 23B smaller than the width of the first heat welding part 23A, the welding strength in the second heat welding part 23B can be lowered by the welding strength in the first heat welding part 23A. It is possible to lower the strength.

The recess 26 is formed in the shape of a groove between the first heat weld part 23A and the second heat weld part 23B, and when the vapor pressure in the accommodation part 20b reaches a predetermined pressure, the second heat weld part When 23B separates from the lid material 50 at any location, it has a function of guiding steam from the separated location to the steam exhaust section 25.

The V-shaped portion 27 is formed in a V-shape so as to close toward one corner 22b of the flange portion 22 (outward) in plan view (see FIG. 2). This allows the user to
When the end of the lid 50 (in this example, the corner 50a of the lid 50 shown in FIG. Since the force is concentrated on the tip 27a side, the lid material 50 can be easily peeled off even with a small force.

In addition, considering that the lid material 50 is easily peeled off due to an increase in vapor pressure or peeled off by the user, at least the second heat welded part 23B of the container body 20 and at least the back surface of the lid material 50 are It is desirable that the materials be combined so that the force required for peeling is small. As a combination of materials that are easy to peel off, for example, at least the second heat-welded part 23B of the container body 20 is made of a mixture of polyethylene (PE) and polypropylene (PP), and at least the back surface of the lid material 50 is made of a material that is a mixture of polyethylene (PE) and polypropylene (PP). For example, a combination of different materials that can be welded may be used, such as polyethylene (PE).

As shown in FIG.
It is inclined downward at an angle θ2 toward b (toward the outside). Due to this inclination, the V-shaped portion 2
The welding strength at 7 can be set to be even smaller than that of the other parts of the second heat welded part 23B.

Further, the V-shaped portion 27 has a recessed portion 27b that is inclined at an angle θ3 toward the bottom 20a of the accommodating portion 20b on the inside thereof in a cross-sectional view. By forming such a recess 27b,
Even if steam escapes from the steam exhaust part 25 and the pressure in the accommodation part 20b is reduced, communication between the inside of the container body 20 (the accommodation part 20b) and the outside is reliably ensured by the recessed part 27b.
can be prevented from becoming a vacuum. The effect of this recess 27b can prevent the lid member 50 from adhering to the contents 11 when the pressure in the storage portion 20b is reduced.

Return to Figure 3. As shown in FIG. 3, the protrusion 24 is on the corner 22b and the steam exhaust part 25
It is provided at a position facing the outside of the The protrusion 24 is arranged near the steam exhaust part 25,
It has a conical base 24a that tapers upward, and a spherical part 24b formed on the top of the base 24a. A corner portion 50a (see FIG. 1) of the lid member 50 is thermally welded to the spherical portion 24b. The protruding portion 24 functions to lock the corner portion 50a of the lid member 50 when the pressure in the accommodating portion 20b is reduced. In this way, by providing the protrusion 24 in the vicinity of the steam exhaust section 25 together with the recess 27b described above, in conjunction with the action of the recess 27b, the lid 50 prevents the contents 1 from being removed when the pressure of the storage section 20b is reduced.
1 can be further prevented from adhering. Note that the configuration of the protruding portion 24 is not particularly limited to this example, and may be of any configuration as long as it can lock the corner portion 50a of the lid member 50 when the pressure in the accommodating portion 20b is reduced.

Next, the operation of the microwave oven container 10 will be explained based on FIGS. 6 and 7. As shown in FIG. 6, when the microwave container 10 is heated in a microwave oven, the lid material 50 expands due to an increase in steam pressure generated within the housing portion 20b. When the lid material 50 expands, force concentrates on the sealing surface of the second heat welding part 23B, and when the steam pressure reaches a predetermined pressure, any part of the sealing surface of the second heat welding part 23B The lid material 50 is peeled off.

As shown by the arrow (1) in FIG. 6, the steam from the peeled portion is guided by the recess 26 to the steam exhaust section 25, and is discharged from the steam exhaust section 25 to the outside. In this example, in the second heat-welded part 23B, which has a lower welding strength than the first heat-welded part 23A, peeling is likely to occur in the V-shaped part 27, where the welding strength is set even lower due to the inclination. In this case, as shown by the arrow (2) in FIG.
) Steam escapes well.

Then, as shown by the arrow (3) in FIG.
and peels off from the V-shaped portion 27. At this time, since the V-shaped portion 27 is formed to close outward, the user can start peeling off the lid 50 with less force and easily remove the lid 50 from the container body 20. be able to.

The effects of the first embodiment described above will be described. According to the first embodiment, the steam passing through the recess 26 between the first heat welding part 23A and the second heat welding part 23B is guided to a predetermined steam exhaust part 25 and discharged to the outside. I can do it. Therefore, compared to the conventional structure in which a through hole is formed in the passage of steam between two convex parts to which the lid is welded, a structure is obtained in which the contents 11 are less likely to leak. The steam can be efficiently discharged from the steam exhaust section 25.

(Second embodiment)
Next, a container body according to a second embodiment of the present invention will be described based on FIG. 8. The above-described accommodating portion 20b (see FIG. 2) of the container body 20 had a substantially square planar shape; however, the accommodating portion 20b
The planar shape of can be selected from various shapes such as approximately square, circular, and oval.

As shown in FIG. 8, for example, in the container body 60 according to the second embodiment, the accommodating portion 20b has a circular planar shape, and the flange portion 22 is formed to extend outward from the circular opening 21. . The flange portion 22 has four corner portions 22b on the outside of the inner portion 22a via steps 22c.
has. A first heat welding part 23 is provided on the inner side 22a of the flange part 22 with the recess 26 in between.
A and a second thermally welded portion 23B are formed. One corner 22b of the flange portion 22
A steam exhaust part 25 and a V-shaped part 27 are provided at a position corresponding to the corner part 22.
A protrusion 24 is provided at a position facing the outside of the steam exhaust portion 25 b.

In the container main body 60 having the accommodating portion 20b having a circular planar shape as described above, similarly to the container main body 20 described above (see FIG. 2), there is a gap between the first heat welding portion 23A and the second heat welding portion 23B. The steam that has passed through the recess 26 can be guided to a predetermined steam exhaust part 25 and discharged to the outside, and the steam can be well discharged from the steam exhaust part 25 in a structure that prevents the contents 11 from leaking. can.

(Third embodiment)
Next, a container body according to a third embodiment of the present invention will be described based on FIGS. 9 and 10. In the third embodiment, the V-shaped portion 27 of the first or second embodiment is replaced with a W-shaped portion 71 (easily peelable portion), and the planar shape of the accommodating portion 20b is approximately an oval shape with rounded corners. It is said that Figure 9 and Figure 1
As shown in FIG. 0, the container main body 70 has an accommodating portion 20b and an opening 21 having a substantially rectangular planar shape. The flange portion 22 extending from the opening 21 is provided with a rib-shaped first heat-welded portion 23A and a rib-shaped second heat-welded portion 23B. The second heat welding part 23B has a W-shaped part 71 formed in a W-shape so as to close outward at a position corresponding to the steam exhaust part 25 in plan view. The W-shaped portion 71 has two outwardly facing tips 71a and one inwardly facing base end 71b.

When the user picks up the lid material 50 and pulls it up to peel it off from the W-shaped portion 71, the user concentrates the force on at least one side of the two tips 71a of the W-shaped portion 71. The lid material 50 can be easily peeled off even with a small force. Further, when the lid material 50 is automatically opened due to an increase in steam pressure, stress is concentrated on the base end 71b of the W-shaped portion 71.
In this case, peeling is more likely to occur. In addition, this W-shaped portion 71 also inclines downward (towards the outside) at an angle θ2 (see FIG. 10) toward one corner 22b of the flange portion 22 in a cross-sectional view. Due to this inclination, similarly to the V-shaped portion 27 described above, the welding strength at the W-shaped portion 71 can be set to be smaller than that at other portions of the second heat-welded portion 23B.

In addition, by setting the width of the inner second heat welding part 23B smaller (skinner) than the width of the first heat welding part 23A, the welding strength of the second heat welding part 23B can be made equal to that of the first heat welding part 23B. Heat welding part 23
The welding strength can be set lower than the welding strength of A. In addition, in the second thermally welded portion 23B having such low welding strength, the W-shaped portion 71 is formed to be narrower (even thinner) than the other portions of the second thermally welded portion 23B. Therefore, the welding strength is the lowest among the first thermally welded portion 23A and the second thermally welded portion 23B.

In this third embodiment as well, the lid member 50 is peeled off particularly at the W-shaped portion 71 of the second heat welding part 23B, and the recess 26 between the first heat welding part 23A and the second heat welding part 23B is removed. The steam passing through can be guided to a predetermined steam exhaust part 25 and discharged to the outside, and the steam can be well discharged from the steam exhaust part 25 in a structure that prevents contents 11 from leaking.

(Fourth embodiment)
Next, a container body according to a fourth embodiment of the present invention will be described based on FIGS. 11 and 12. In the fourth embodiment, in the third embodiment, the first heat welding part 81A and the second heat welding part 81B
It is made into a band shape. As shown in FIGS. 11 and 12, the container body 80 has an accommodating portion 20b and an opening 21 having a substantially rectangular planar shape. Flange portion 2 extending from opening 21
2, a band-shaped first heat-welded part 81A and a band-shaped second heat-welded part 81B (both welded parts are flat parts shown in a dot pattern in FIG. 11) are formed. That is, the first heat welding part 81A and the second heat welding part 81B are not rib-shaped, but have a space (non-thermal) through which steam can pass between the first heat welding part 81A and the second heat welding part 81B. The welded portion 82) is formed into a flat shape within the range that can be formed. Further, the second heat welding part 81B has a W-shaped part 71 that is closed toward the outside and has a flat shape at a position corresponding to the steam exhaust part 25 in a plan view.

More specifically, the first thermally welded portion 81A and the second thermally welded portion 81B are formed using a seal head 90 for thermal welding (see FIGS. 12 and 13(a) to (c)). can do. That is, the seal head 90 has a first convex portion 91A corresponding to the first heat welded portion 81A.
and a second convex portion 91B (both convex portions are indicated by diagonal lines in FIGS. 13(a) and (b)) corresponding to the second thermally welded portion 81B, and these first convex portions 91A By pressing the flat lower surfaces of the second convex portions 91B against the flat upper surface of the flange portion 22 via the lid material 50, the first heat welded portion 81A and the second heat welded portion welded to the lid material 50 are removed. Thermal welding part 81B
is formed on the upper surface of the flange portion 22. Note that FIG. 11 shows the container body 80 after the lid material 50 has been heat-welded to the flange portion 22, and the first heat-welded part 81A and the second heat-welded part 81B are shown with solid lines for easy understanding. , the lid member 50 is shown by an imaginary line (two-dot chain line).

Further, as shown in FIG. 12, in the seal head 90, the lower end of the inner second protrusion 91B may be set at a higher position than the lower end of the first protrusion 91A, or the lower end of the inner second protrusion 91B may be By forming the upper surface 81B1 of the corresponding flange part 22 at a lower position than the upper surface 81A1 corresponding to the first heat welding part 81A, the welding strength of the second heat welding part 81A is lower than that of the first heat welding part 81A. The welding strength of the welded portion 81B can be set low. In addition, in the seal head 90, by setting the width of the second convex portion 91B smaller (thinner) than the width of the first convex portion 91A, the welding strength of the second heat welding portion 81B is lowered by the first heat welding portion 81B. The welding strength can be set lower than the welding strength of the welded portion 81A. In addition, as shown in FIG. 13(b), the second
In the convex portion 91B, by setting the width W1 of the portion 91B1 corresponding to the W-shaped portion 71 to be narrower (thinner) than the width W2 of the other portion 91B2 excluding the portion 91B1 corresponding to the W-shaped portion 71. , in the second thermally welded portion 81B with low welding strength, the W-shaped portion 71 is formed to be narrower (further thinner) than the other portions of the second thermally welded portion 81B. The welding strength is the lowest among the thermally welded portion 81A and the second thermally welded portion 81B. Furthermore, in the second convex portion 91B of the seal head 90, as shown in FIG. 13(c), the lower end position of the portion 91B1 corresponding to the W-shaped portion 71 is set higher than the lower end position of the other portion 91B2. As a result, the welding strength of the W-shaped portion 71 in the second thermally welded portion 81B can be further reduced.

Also in this fourth embodiment, the lid material 50 is peeled off particularly at the W-shaped portion 71 of the second heat welded portion 81B, and the lid material 50 is peeled off at the portion corresponding to the recessed portion 26 (see FIG. 2) according to the first embodiment described above. Steam that has passed through a certain non-thermal welding part 82 can be guided to a predetermined steam discharge part 25 and discharged to the outside, and the steam can be well discharged from the steam discharge part 25 in a structure that prevents the contents 11 from leaking. can do.

Although the present invention has been described above using the embodiments, it goes without saying that the technical scope of the present invention is not limited to the scope described in the above embodiments. For example, in the first and second embodiments, the V-shaped part 27 of the second heat welding part 23B may be replaced with the W-shaped part 71 of the third and fourth embodiments, or conversely, the In the fourth embodiment, the W-shaped portion 71 of the second heat-welded portion 23B or the second heat-welded portion 81B may be replaced with the V-shaped portion 27 of the first and second embodiments. Furthermore, in the first and second embodiments, the rib-shaped first heat welding part 23A and the second heat welding part 23B are replaced with the band-shaped first heat welding part 81A and the second heat welding part 81A of the fourth embodiment. It may be replaced with a welded portion 81B. Thus, it will be apparent to those skilled in the art that various changes or improvements can be made to the embodiments described above. Furthermore, it is clear from the description of the claims that such modifications or improvements may be included within the technical scope of the present invention.

DESCRIPTION OF SYMBOLS 10... Container for microwave oven, 11... Contents, 20... Container main body (1st embodiment), 21... Opening, 22... Flange part, 23A... First heat Welding part (first to third embodiments), 23B...second thermal welding part (first to third embodiments), 24...protrusion, 25...steam discharge part, 26.. .Recess, 27
... V-shaped part (easy peeling part), 27b... recessed part, 50... lid material, 60... container body (second embodiment),
70... Container main body (third embodiment), 71... W-shaped part (easily peelable part), 80... Container main body (fourth embodiment), 81A... First heat welding part ( 4th embodiment), 81B...Second thermal welding part (4th embodiment), 82...Non-thermal welding part

Claims (3)

A method for manufacturing a microwave container, the method comprising:
A step of thermally welding a lid material to a flange portion formed to extend outward from the opening of the container body,
The heat welding is performed by pressing the convex part of the seal head against the flange part through the lid material,
The convex portion includes first and second portions that are connected to each other via an inclined surface,
The height of the first part is lower than the height of the second part,
The opening is a quadrilateral with rounded corners in plan view,
The first portion has a W-shaped inner edge and an outer edge, and is provided at a position adjacent to the roundness,
The W-shape has two distal ends facing outward and one proximal end facing inward. The method according to claim 1 ,
The method, wherein the convex portion is pressed against a flat surface of the flange portion. The method according to claim 1 or claim 2 ,
The method, wherein the convex portion is pressed against the flange portion so as to surround the opening.

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