JPS61273363A - Sealed package - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to the structure of a sealed package whose opening is heat-sealed, such as a bag or disposable container.

[Conventional technology]

For example, one of the requirements for a package in which the opening of a molded container body is heat-sealed with a lid is that it be easy to open by hand. For this purpose, make a cut in a part of the lid in advance, etc.
Although various ideas have been made, it is common practice to make the container body easily peelable by pulling the lid by hand.
It is designed to have a width of ~2.0~/15 mm.

On the other hand, since it is inconvenient for the heat-sealed part to come off during handling such as hot water treatment or transportation, it is also required that the heat-sealed part does not peel off easily. For example, according to the Japanese Agricultural Standards (JAS), when labeling retort food, cut out a sample of the sealed part in a pouch and measure the peel strength, and if the peel strength is 2.3 K9 or more, It is said that it will not happen. Needless to say, this exceeds the limit that can be easily peeled off by hand.

[Problem of invention]

Further consideration of the above two requirements shows that in order to sufficiently protect the contents during the distribution process of a sealed package, the greater the peel strength from the inside of the package, that is, from the inside of the heat-sealed part, the better. On the other hand, when opening the package, the peel strength from the outside of the heat-sealed part is weakened (it can be seen that the package can be opened easily).

Therefore, an object of the present invention is to provide a structure of a sealed package in which the heat-sealed portion has a high peel strength from the inside and a low peel strength from the outside.

[Means for solving problems]

In order to solve the above problems, in the present invention, a protruding strip is formed on the heat sealing part provided near the opening of the package, and the cross-sectional shape of the protruding strip is changed from the outside of the package to the inside, that is, The height of the protrusion gradually increases from the outer edge to the inner edge, and the outer edge is made into a zigzag curve, and the inner edge is made into a nearly smooth line. The other or the sealing member was heat sealed to form a sealed package.

[Effect]

When the above-mentioned protrusions are provided, the adhesive strength with the other side to be heat sealed gradually weakens from the inner edge to the outer edge.
In addition, since the adhesive line forms a zigzag pattern at the outer edge of the convex strip, the peel strength from the outer edge direction is small and it can be easily peeled from outside the opening, while the inner edge has a high adhesive strength and the adhesive line The peeling strength is extremely high because it is almost linear and almost perpendicular to the peeling direction.

〔Example〕

As shown in FIG. 1, the opening 2 of the container body 1 is provided with seven flange 3 on its periphery, and on the upper surface of the seven flange 3,
A protruding strip 4 is formed. Further, the flange 3 includes:
A lid 10 serving as a sealing member is heat-sealed, and the opening 2 is sealed.
is closed to form a sealed package.

As shown in FIG. 2, the protruding strip 4 has a cross-sectional shape whose height gradually increases from the outer edge 5 to the inner edge 6.

Further, as shown in FIG. 2(C), the height may gradually increase from the outer edge 5, and the vicinity of the inner edge 6 may become a flat surface 7. Alternatively, as shown in Figure 2), the outer edge 5
The height may gradually increase from there, and after reaching the apex 8, it may slope downward in the direction of the inner edge 6. In this case, it is desirable that the upward slope from the outer edge 5 has a gentler angle.

In addition, as shown in FIG. 2(b), the inside of the protrusion 4 may be hollow. In addition, the protrusion 4 does not necessarily have 7 lunges 3.
It is not necessary to provide it in the center of the 7 flange 3, and it may be located near the outer edge or inner edge of the 7-lunge 3.

Here, the height of the ridge 4 is 0.5 to 4 degrees, preferably 1.0 to 2.0 degrees, and the width is 0.5 to 10 degrees, preferably 2.0 to 5.0 degrees. This is the item.

As shown in FIGS. 3 and 4, the outer edge 5 of the protrusion 4
The inner edge 6 forms a relatively small zigzag bending line.
is almost a smooth line.

This curved line does not necessarily have to be provided all around the circumference; for example, the corner 9 may be a smooth line as shown in FIG.

The shape of the curved line of the outer edge 5 can be selected from various shapes as shown in FIG. Also, as shown in Figure 5 (e),
A portion of the curved line of the outer edge 5 may be substantially in contact with the inner edge 6.

The bending line of the outer edge 5 as described above is for facilitating peeling, and in order to fully exhibit this effect, it must be at least 30% longer than the length of the inner edge 6.

The material of the container body 1 and the lid 10 may be any material as long as it can be heat-sealed, and it does not matter whether it is a single body or a laminate. For example, the container body 1 may be a polypropylene molded product, and the lid 10 may be a laminate of aluminum foil and thermoplastic resin.

Further, the protruding strip 4 may be formed on the lower surface of the lid 10.

In this case, the upper surface of the 7-lunge 3 is kept flat.

As shown in FIG. 6, the sealed package may be a bag.

In this case, a protrusion 4 is formed on one of the inner surfaces of the opening 2, or a separate protrusion 4 is fixed. The surface facing the protrusions 4 may be flat.

In addition to the above-mentioned bags, the present invention can also be applied to boxes and the like.

Next, an example of a method for heat-sealing the lid 10 to the container body 1 will be explained based on FIG. 7.

As shown in the figure, the lid 1° is placed on the flange 3 of the container body 1, and while the lower surface of the flange 3 is supported by the lower mold 30 of the heat-sealing hot plate, an elastic material such as heat-resistant rubber fixed to the lower surface of the upper mold 20 is used. The upper surface of the lid 10 is heated under pressure by the body 21. What is important here is to prevent the ridges 4 from deforming as much as possible due to pressure and heating.

When heat-sealing is performed as described above, a heat-sealed portion is formed in and around the protruding strip 4, but the outer edge 5 of the protruding strip 4 is
Since the pressing force increases in the direction from the inner edge 6, the adhesive strength is weakest near the outer edge 5 and maximum at the inner edge 6. Furthermore, the adhesive line is zigzag along the outer edge 5 of the protrusion 4, and is a smooth line at the inner edge 6. Therefore, when the lid is pulled up from the outside of the container, it can be easily peeled off, but it cannot be peeled off easily from the inside.

In addition, in FIG. 7, 11 is a base material of the lid, and 12 is an adhesive layer.

If the adhesive layer 12 has a sufficient thickness and has a cushioning effect, the elastic body 21 of the upper die 20 is not required. Furthermore, grooves corresponding to the protrusions of the lid 10 may be provided on the lower surface of the upper die 20. In this case as well, elastic body 2
1 is unnecessary.

Next, more detailed examples and comparative examples will be given.

Now, 10 round containers each having an internal volume of 150 cc were made by thermoforming polypropylene sheets with a thickness of 500 μm. Seven lunges of these containers were provided with a protrusion having a height of one shoulder, a width of 2.5 mm, and a serrated outer edge.

On the other hand, a 50 μm thick soft aluminum foil and a 35 μm thick modified high-density polyethylene film were bonded together with the thermosetting urethane adhesive side, and then punched into a shape that matched the 7 lunges of the container to create a lid.

Each of the containers described above was filled with water, the lids were placed on the flanges, and the containers were sealed by heat-sealing with heat-resistant rubber. The conditions are: rubber surface temperature 200℃, pressure 3? /cd
, the time was 1 second.

Furthermore, this sealed container was subjected to retort sterilization at 120° C. for 30 minutes.

As a comparative example, 10 containers were prepared that had flat flange tops and were otherwise similar to the examples, and were filled with water in the same manner.
Heat sealing was performed using the same lid under the same conditions.
Retort sterilization was performed.

When I peeled off the lids of all of these sealed containers by hand, I was able to easily open them.
When a sample of an width was cut out and the peel strength from the inside of the container was measured, the peel strength of the example was 2.5 to 4. OK! i
'/15 wn width, whereas the comparative example had a width of 0.8 to 1-2 KF/15 wn.

〔effect〕

According to the present invention, as described above, a protruding strip is provided on one side of the heat-sealed portions that are heat-sealed to each other, and the cross-sectional shape of the protruding strip is gradually increased in height from the outside to the inside of the sealed package. In addition, the outer edge of the protrusion was made into a zigzag bent line, and the inner edge was made into a nearly smooth line, so that the adhesive strength was minimum at the heat-sealed part of the outer edge, and the adhesive line was in the peeling direction. Since it forms an acute angle with respect to the adhesive, it can be easily peeled off, and the heat-sealed part on the inner edge has the highest adhesive strength and the adhesive line.

Since the peeling direction is substantially perpendicular to the peeling direction, the peeling strength is extremely high, and a package with excellent protection performance for contents can be obtained.

[Brief explanation of the drawing]

Figure v41 is a sectional view showing an embodiment of the sealed package, Figure 2 is an enlarged sectional view showing the flange portion of the same as above, Figure 3 is a perspective view of the same as above, fs4FI! J is a plan view of the sealed package, and FIG.
′! Figure J6 is a perspective view showing another form of the sealed package;
The figure is an enlarged sectional view showing a method of heat sealing the package. 1... Container body, 2.2'... Opening, 3...7
Lunge, 4... Convex ridge, 5... Outer edge, 6... Inner edge, 1o... Lid.

Claims (1)

[Claims] In a package that is sealed by heat-sealing the opening with a sealing member or by heat-sealing one side of the opening to the other side, a protruding strip is provided on one side that is mutually heat-sealed, and the protruding strip is The cross-sectional shape is such that the height gradually increases from the outside to the inside of the opening, that is, from the outside edge of the protrusion to the inside edge, and the outside edge is a zigzag curved line and the inside edge is a nearly smooth line. A sealed package characterized by: