JPS6144726B2 - - Google Patents

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a method for sealing a lid on a container, and more specifically, a method for sealing a lid on a container, and more specifically, a method for sealing a lid on a container having a synthetic resin layer on the flange surface. The present invention relates to a method of sealing by heat compression bonding.

(Prior art) For example, it is well known that a lid made of metal foil or a paper lid is placed on a paper container coated with synthetic resin on both sides, and these are integrated by bonding, fusing, etc. ing. In addition, for vacuum packaging or gas exchange packaging, one seal of a tray-shaped container having seals on all sides of the storage part is made uneven.
After the contents are stored in the storage part of this container and the three smooth sealing parts are sealed, this container is put into a direct air packaging machine or a gas replacement packaging machine to perform direct air suction or gas replacement. Vacuum suction or gas replacement is performed in the uneven gap between the unsealed uneven seal portion and the lid, and after this is completed, this seal portion is sealed to prevent vacuum packaging or gas replacement packaging. A container for this purpose is shown in Japanese Utility Model Application Publication No. 162502/1983.

(Problems to be Solved by the Invention) However, these conventionally known containers also have various drawbacks. For example, when a lid made of metal foil or a paper lid is placed on the above-mentioned container, that is, a paper container coated with synthetic resin on both sides, and the lid is heat-pressed and sealed, the lid will swell in most cases. It is glued to the container in an open state. In this case, there is no problem as long as the lid is thick and hard enough to prevent it from swelling, but if the lid is mainly made of metal foil or thin paper, this bulge will not occur. Hard to avoid. This bulge in the lid becomes an obstacle when containers are stacked during storage, transportation, and handling. In addition, this bulge is caused by an extra amount of air being trapped inside the container, so if the contents of the container are items that do not like oxidation, it is simply an inconvenience or inconvenience in handling the container. In addition to causing inconvenience in handling the container, it may also cause deterioration in the quality of the contents. It is required that the lid be attached to the container to prevent it from leaking. In addition, containers used for vacuum suction or gas replacement have an uneven seal on the container seal for air suction or gas replacement in the container. It is not easy to seal the seal part and the lid. That is, as a matter of course, the container is required to have strength since the contents are placed therein, so the container must be considerably thick. In addition, when sealing these uneven parts, adhesive bonding or heat fusion may be considered, but considering the necessity of sealing within the chamber of a vacuum packaging machine or gas displacement packaging machine, it is recommended to use adhesive. Since bonding is not possible, both the container and the lid must be made of synthetic resin; in particular, the container cannot be made of any other material, such as paper. These containers and lids must be bonded by heat, but in this case, in order for the uneven seal portion and the lid to adhere and flatten, the seal of the container, which has a considerable thickness, must be used. It requires considerable temperature, time, and pressure to flatten the unevenness of the parts, and special packaging such as vacuum packaging or gas exchange packaging is required, and efficiency has to be ignored. It is something.

(Means for Solving the Problem) The inventors of the present invention have therefore discovered that when a lid is sealed on a container, it can be attached without any excess air remaining in the container and without causing any bulging. Therefore, depending on the contents of the container, the quality deterioration due to residual air can be avoided to that extent, the container can be handled without any inconvenience or inconvenience, and there are no restrictions on the material of the container and the lid can be handled efficiently. As a result of various research and repeated experiments, the inventors have found that when sealing a lid having a metal foil and a synthetic resin layer to a container having a synthetic resin layer on the flange surface, the container can be used as a lid. The part other than the part to be placed on the flange of the lid is made into a recess by preliminary molding, and the metal foil and synthetic resin layer from the edge of the lid to the recess are formed by this preliminary molding. A lid with a large number of folds communicating from the inside to the outside is used, and after the lid is placed on the flange of the container, the width of the flange is covered with a portion or all of the width of the flange. A satisfactory sealing method was achieved by crushing and flattening the folds formed on the lid by heat-compression bonding over the entire circumference of the lid, and by fusing and sealing the synthetic resin layer between the lid and flange. That's what I got.

(Function) In the present invention, as shown in FIG.
The portion other than the portion placed on the flange 4 is a recessed portion. At the same time, by this preliminary molding, as shown in FIG.
A large number of folds 13 are formed toward the lower end 12 of 1. If the lid 5 constructed in this manner is attached to the container 1, the lower surface of the recessed portion of the lid 5 will be located below the surface of the flange 4 of the container 1. This means that the concave portion of the lid 5 enters a part of the container 1, and at this time, the lid 5 has an edge 1 of the lid.
Numerous folds 13 from 0 to the lower end 12 of the slope 11
The folds 13 are formed as air passages extending from the inside to the outside of the flange 4 of the container 1, so that when the lid 5 is attached, Since the lower surface of the recess 5 is located below the surface of the flange 4, the recess of the lid enters the container, and air equal to the volume that the lid 5 enters,
It will be released from the container through the folds 13. This can be done by simply placing the lid on the container without requiring any special operations. By removing a portion of the air from the container in this manner, no extra air remains within the container. After this, the folds formed on the lid are crushed and flattened by heat-pressing, and the synthetic resin layers of the lid and flange are fused and sealed. This fusion sealing by crushing the folds is applied to part or all of the width of the flange,
Moreover, this is achieved by performing the process over the entire circumference of the flange.

(Example) Next, an example of the implementation of the present invention will be described with reference to the accompanying drawings. Reference numeral 1 is a container, which is made of, for example, paper 2 coated with polyester resin 3 on both sides. It has a flange 4. 5 is a lid, and a polyester film 8 is adhered to the back surface of an aluminum foil 6 with an adhesive 7. This lid 5 is first subjected to preliminary molding. In this preliminary molding process, as shown schematically in FIG. 2, a flat lid 5 is placed on top of the container 1.
When the lid 5 is pressed from above with a pressing body 9 which is of the same type and size as the lid 5 and has a cross-sectional shape as shown, the lid 5 is deformed into a dish shape with a flange. That is, this part of the brim is a part that is placed in contact with the flange of the container 1, and the part inward from the slope 11 is a part located inward of the container 1 and is a recessed part. Along with the formation of a recessed portion by the pressing of the pressing body, the lower end 12 of the slope 11 is
A large number of folds 13 are formed throughout. This fold 13
By forming the lid 5, a fine air passage is formed in the lid 5, extending from the inside of the container 1, which stores the contents, to the outside end of the flange 4. Next, when the flange 4 is heated and pressed with a heating and pressing ring 14 having a width narrower than the width of the flange 4 of the container 1, the polyester film 8 of the lid 5 and the container 1 are heated and pressed.
Polyester resin 3 coated on paper 2
At the same time, the folds 13 formed on the lid 5 by the pressure of the annular body 14 are crushed and flattened to form an annular groove 15, whereby the lid 5 and the folds 13 are finally bonded together. The container 1 is tightly sealed.

In the present invention, preliminary molding for forming the recesses and pleats in the lid is not only carried out with the lid placed on the container, but also by preparing a lid that has undergone preliminary molding in advance and placing it on the container. It is also possible to place it thereon and then heat and press it with a heated press ring. Furthermore, the pleats formed on the lid need to be longer than the width of the flange of the container when the lid is placed on the container. That is, since the unevenness caused by the formation of the folds serves as an air discharge path, this discharge path must be longer than the flange of the container.

In the present invention, the width of the annular groove formed when the lid is heat-pressed and sealed, that is, the annular groove formed by crushing the folds and making it flat, is:
It is necessary that the groove is the same as or narrower than the width of the flange of the container, and the groove needs to be formed all around the flange. If this is not done, it will not be possible to completely block the flow of gas and liquid between the inside and outside of the container after the lid is sealed.

In the above explanation, the container is paper coated with polyester resin on both sides.
Although the lid used was a polyester film bonded to aluminum foil with an adhesive, the present invention is not limited to this, and any other form of container and lid may be used.

(Effects of the Invention) As described in detail above, the present invention uses a container having a synthetic resin layer on the flange surface, and uses a lid having a metal foil and a synthetic resin layer as a lid disposed thereon. Furthermore, by applying a preliminary mold to this lid, the part other than the part that will be placed on the flange of the container is made into a recess, and at the same time, the metal foil and synthetic resin from the edge of the lid to the recess are teeth,
By using a container with a large number of pleats that communicate from the inside to the outside, the lid can be placed inside the container without any special means simply by placing the lid on the container. The air in the volume occupied by the recesses is discharged from the air discharge path by the folds, so that no excess air remains in the container. The folds formed on the lid over the entire circumference are crushed and flattened by heat-pressing, and the synthetic resin layer of the lid and flange is fused and sealed to completely isolate the inside and outside of the container. It is. This method can be applied regardless of what material the container is made of, or what its thickness, strength, etc. Therefore, it is possible to apply a plastic coat on both sides of the container. It is also preferably applied to paper cups etc. As shown in the above-mentioned Japanese Utility Model Publication No. 162502/1986, the seal part of the container itself is deformed to form an air flow path, but the lid is deformed before it is sealed. Since the sealing portion must be flattened, the material for this container is limited to plastic that can be heat-sealed, which limits its scope of application to an extremely narrow range.

In addition, for sealing, it is only necessary to crush the folds formed on the lid, that is, the folds made of the metal foil and synthetic resin layer of the lid, by heating and pressing. Compared to deforming, it is extremely efficient because the lid can be tightly attached to the container with less pressure, time, and temperature, and the inside and outside of the container can be shut off. The container obtained in this way completely blocks the flow of gas as well as liquid between the inside and outside of the container, and there is no problem in storing and handling the container, and the quality of the contents of the container is affected. This invention has made an extremely large contribution to this type of container, as it has no adverse effects.

[Brief explanation of the drawing]

The accompanying drawings are for explaining an example of the implementation of the present invention. Figure 1 is a cross-sectional view showing the state before the lid is sealed on the container, and Figure 2 is a sectional view showing the state before the lid is sealed with pleats. 3 is a plan view showing an example of a lid provided with pleats; FIG. 4 is a sectional view of essential parts showing an example for crushing the pleats and simultaneously sealing the lid and the container; FIG. 5 is a plan view of the main part of the lid showing a state in which the lid and the container are attracted and sealed, the folds of the lid are crushed and flattened, and an annular groove is formed. 1: Container, 3: Synthetic resin layer, 4: Flange of container, 5: Lid, 6: Metal foil, 8: Synthetic resin layer, 1
3: Folds, 15: Annular grooves formed by crushing the folds and making them flat.

Claims (1)

[Claims] 1. When sealing a lid having metal foil and a synthetic resin layer to a container having a synthetic resin layer on the flange surface, the portion other than the portion placed on the flange of the container as the lid is formed into a recess by preliminary molding. In addition, due to this preliminary molding, numerous folds were formed in the metal foil and synthetic resin layer from the edge of the lid to the recess, which communicated from the inside to the outside of the lid. After placing the lid on the flange of the container, the folds formed on the lid are pressed by heating and crimping over part or all of the width of the flange, and also over the entire circumference of the flange. Along with crushing and flattening,
A method for sealing a lid on a container, which comprises fusing and sealing a synthetic resin layer between the lid and the flange.