JPH027819Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a highly airtight paper container. More specifically, the present invention heats and adheres a lid material made of a thermoplastic plastic film to the entire area around the mouth edge of a paper container whose entire interior is laminated with a plastic film.
This invention relates to a container whose interior can be kept completely sealed for a long period of time.

(Prior Art) Conventionally, so-called one-way containers, such as paper containers (hereinafter referred to as
A fixed amount of sour yogurt, milk, etc. is filled into a ``laminate container'' (called a ``laminate container''), and a laminated film is placed.
Some containers are heat-sealed by covering the rim of the container with a lid material made of the same or different film.

(Problems to be Solved by the Invention) Conventional containers have the disadvantage of poor airtightness. That is, in a conventional sealed one-way container, for example, a thermoplastic plastic film is laminated on the inner surface of an outer container material made of paper, and the upper edge of the side wall of the container is curled to form an opening edge. It is obtained by heat-sealing the lid material to the container body. Therefore, as shown in FIG. 1, in a conventional one-way container, the bonding state between the container body 100 and the lid material 3 is such that the lid material 3 of thermoplastic film is attached to the edge of the container (thermoplastic plastic film 2 200 (which is laminated), and an extremely small communication hole 400 is formed between the lid material 3 and the step 300 that occurs at the joint portion of the container, that is, the side seam portion 1. As a result, the communication hole 400
For example, the liquid filled inside the container may evaporate, the contents that have risen due to capillary action may leak out of the container, or gas dissolved in the liquid may escape, or ,
Carbon dioxide gas in the atmosphere may enter the container through the communication hole 400 and cause a chemical reaction with the substance filled inside the container, or moisture in the atmosphere may enter the container through the communication hole 400. If the substance filled inside the container is a deliquescent substance, or a substance that ignites or changes quality due to moisture absorption, an inconvenient situation may occur. Furthermore, when heat-sealing the lid material after curling the upper edge of the side wall of the laminated container to form the mouth edge, it is necessary to curl the upper edge of the side wall of the laminated container to form the mouth edge. In addition to creating communication holes and impairing airtightness, the bonding area between the edge of the container and the film that makes up the lid material is extremely small, resulting in poor sealing in other areas as well. Sometimes. For example, due to irregularities in molding, some unevenness may occur around the upper edge of the mouth edge other than the side seam, and as a result, the film 3 of the lid material is perfectly aligned with the container mouth edge 200. There is no surface contact, but so-called point contact where non-bonded parts exist here and there. Therefore, the non-jointed portion also causes a decrease in airtightness, leading to the above-mentioned situation. Therefore, the use of conventional one-way containers is severely limited due to their poor sealing properties.

(Means for Solving the Problems) Therefore, the purpose of the present invention is to provide a simple paper container that can be used for an extremely wide range of purposes and that can maintain perfect airtightness over a long period of time. It is.

Other objects and advantages of the present invention will become apparent as the description proceeds.

As a result of many years of extensive prototyping and research in order to improve the sealing performance of conventional so-called one-way paper containers, the inventor of the present invention found that after forming the rim of a laminated container, plastic film lid material was applied to the container opening. Rather than heat sealing the edges, before curling the top edge of the sidewall of the laminate container to form the mouth edge, the plastic film lidding material is stretched to at least the end of the top edge of the sidewall of the container; By heating and curling the upper edge of the side wall of the container together with this plastic film lid material, the container mouth edge is formed, and at the same time, the plastic film lid material covers the entire surface around the mouth edge of the laminated container. The inventors discovered that surface contact with the material allows for a strong bond and an extremely high level of sealing performance, resulting in the completion of the present invention.

That is, in conventional airtight containers, the lid material is heat-sealed after the mouth edge is formed, so the mouth edge and the lid material are joined by point contact, but according to the present invention, the upper edge of the side wall of the container Since the lid material and the lid material are curled together, the lid material always makes complete surface contact with the mouth edge, resulting in a high degree of sealing performance. The most preferable surface contact is, for example, as shown in FIG.
The thermoplastic film lid material is bonded all the way around the rim of the container so that it reaches at least the end 6 of the rim of the container. Furthermore, as shown in FIG. 2, the lid material does not come into surface contact with the side wall of the container body, but merely makes line or point contact. With this configuration, the mouth edge can be elastically deformed, and the deformation of the entire container when filled with contents can be absorbed only by the deformation of the mouth edge.

There has never been a successful production of a highly airtight paper container. Japanese Patent Publication No. 1989-1989 discloses a container main body 1 having a pre-curled container edge (i.e., prim), and a cover 3 which is bent and pretreated to match the shape of the edge. A method of sealing a container is taught which consists of covering it. The inner surfaces of the container body 1 and cover 3 taught in this publication are coated with a thermoplastic synthetic resin such as polyethylene. However, this method is irrelevant to the present invention. The container of the present invention is made of paper, whereas the container material of the public law is metal. Further, in the present invention, the upper edge of the container body and the lid member are curled together, whereas in this publication, the mouth edge is formed in advance.

Further, Japanese Patent Application Laid-Open No. 47-31786 teaches a method of manufacturing a metal container with a high degree of sealing by curling the metal container body and the metal lid together. A heat-sealable coating that can be heat-welded is applied to the inside of both the metal container body and the metal lid. However, JP-A No. 47-31786
The container disclosed in the publication is also the same as the above-mentioned Special Publication 1989
Like the container disclosed in the publication, it is metallic,
This is different from the present invention which provides a paper container. In particular, since the mechanical plastic workability of metal and paper is completely different, Japanese Patent Application Laid-Open No. 47-31786 proposes a highly airtight seal by curling the upper edge of the metal container body and the metal lid member together. Even though it is taught that sexual containers can be obtained, no one skilled in the art would think that a similar treatment would be possible for paper members. When metal is bent, it has plastic formability that allows it to maintain its bent shape, but in the case of paper, even if it is bent, it returns to its original unbent state due to the paper's inherent repulsive stress. It has the characteristic of trying to

In other words, Japanese Patent Publication No. 35-1989 and Japanese Patent Application Laid-Open No. 47-31786 teach a new method for sealing metal cans, and do not provide any suggestions regarding highly airtight paper containers and their manufacturing method. It does not give

Publication No. 43-14834 and Special Publication No. 51-15476
The publication discloses a wax coated paper cup which is made by heat-sealing a metal foil lid member to a wax coating cup. The lid disclosed in this reference is a molded lid made of metal such as aluminum foil. A thermoplastic adhesive is applied to the container rim or to a position corresponding to the container rim on the inside of the metal foil molded lid. When the lid member is placed over the edge of the container and heated, unnecessary wax is melted and the container and lid are integrated by the action of the adhesive.

The present invention does not use a metal foil molded lid and an adhesive as disclosed in the above publication. Furthermore, the end of the lid member in this publication does not reach the end of the container mouth edge. Therefore, the lid rim of the publication cannot undergo elastic deformation to absorb the deformation of the container body.

On the entire inner surface of the paper outer container material 5 of the present invention,
Since the thermoplastic plastic film is laminated, the lid material can be bonded to the plastic film on the inner surface of the container by heating.

As the lid material, a film made of thermoplastic synthetic resin can be used. For example, polyethylene, ionomer, polypropylene, EVA, PVC, polyvinyl alcohol, polyester, nylon,
Films such as polyvinylidene chloride can be used. However, in order to obtain high bonding strength, the material of the lid material is preferably the same material as the film laminated on the inner surface of the container.
From the viewpoint of economy, processability, and high airtightness, the laminate film and lid material on the inner surface of the container are
It is preferred to use polyethylene for both.

The thickness of the film used as the lid material is not an absolute requirement of the invention. That is, an appropriate thickness may be selected by comprehensively considering the mechanical strength of the selected film and the type and properties of the items to be filled inside the container. Such selection of the type of film to be used and the thickness of the film can be easily made by those skilled in the art. Also,
If the product to be filled inside the container is sensitive to external light, such as food, or if it undergoes chemical changes due to ultraviolet rays, the plastic film used as the lid material should not be used to block light. It is preferable to use a specially colored film. However, if no light shielding is required, transparent plastic film can be used as the lid material.

The method for manufacturing a highly airtight container of the present invention is as follows: () A thermoplastic plastic film 8 is laminated on the entire inner surface of a bottomed outer paper container material 5, and the upper edge of the side wall of the container material is curled. Fill the container body with a predetermined amount of filling contents into the container body, which does not have a rim formed by the opening. () Form a container mouth edge 500 by heating and curling the upper edge of the side wall of the container body and the lid material together, and the lid material 7 at least covers the container mouth. This consists of joining the lid material 7 to the entire surface around the mouth edge so as to make surface contact with the edge.

(Example) With reference to FIGS. 3 and 4, a manufacturing example will be described as an example of the present invention. A container with a thermoplastic film 8 laminated on the inner surface is placed on the lifter 14, the upper edge 10 of the side wall of the container 5 is slightly bent toward the outside of the container, and then a desired amount of the desired product is filled into the container. A lid material 7 made of thermoplastic film is placed over the folded upper edge of the side wall of the container so as to extend at least from one end to the other. The lifter 14 is free to rotate due to bearings, and is moved from the inlet to the outlet of the curling machine 11. The container 5 is carried by a lifter 14 to the entrance of the curling machine. A chuck 15 descends at the entrance of the curling machine 11 and clamps the container between it and a lifter 14. The chuck 15 can move up and down and is rotated by gears. The chuck 15 also moves from the entrance to the exit of the curling machine 11 in the same way as the lifter 14. When the chuck 15 reaches the inlet of the curling machine 11 while holding the container together with the lifter 14, the chuck 15 starts rotating and begins to move from the inlet to the outlet. The upper edge 10 of the container side wall is the lid material 7
Together with this, it enters the grooves of the curling ring 16 and the curling wheel 17. The groove 12 cut into the curling ring 16 is deep at the entrance and becomes shallower as it approaches the exit. The curling ring 16 and its groove are provided so as to gradually approach the axis of the curling wheel 17 from the inlet to the outlet. The curling wheel is also provided with grooves 12'. curling ring 1
A heating device (for example, a heater) 13 is disposed around the grooves of the curling wheel 6 and the curling wheel 17. The curling wheel is rotated by a gear, and the curling wheel 17 starts rotating slightly before the upper edge of the container held between the lifter 14 and the chuck 15 and the lid material reach the entrance of the curling machine. The container is held between the lifter and the chuck and moves between the curling wheel and the curling ring while rotating in the groove, and during the movement, the upper edge 1 of the container
0 is heated together with the lid material 7 and is curled to form a prim, and at the same time becomes a paper container with a high degree of sealing and is passed through the curling machine 11.
It is discharged from.

(Effect of the invention) As in the present invention, the lid material 7
Compared to the conventional heat-sealed container shown in FIG.
The communication hole 400 formed in the opening 400 is completely covered and hidden by the film of the lid material, and the film of the lid material is joined to the entire circumferential surface of the container mouth edge 200 in a perfect surface contact manner. There is no possibility of problems such as loss of sealing properties due to such point contact. In this way, a paper container can be obtained which has extremely high airtightness despite being a simple laminated paper container. Therefore, the paper container of the present invention can be used not only for food, but also for filling items that require a high degree of airtightness, such as drying oil, semi-drying oil, deliquescent agricultural chemicals, etc. Has a wide range of uses.

In any case, the discovery that a highly airtight paper container can be obtained inexpensively and extremely easily by curling the upper edge of the side wall of the laminate container body together with a thermoplastic plastic film and heating it. is groundbreaking.

[Brief explanation of the drawing]

FIG. 1 is a partially enlarged view of a one-way container in which a conventional lid material is heat-sealed to the upper edge of the container mouth. FIG. 2 is an enlarged partial sectional view showing the state of connection between the lid material and the container mouth edge at the side seam portion of the container of the present invention. FIG. 3 is a schematic plan view showing an example of manufacturing the container of the present invention. Figure 4 is the third
It is a partially cutaway sectional view taken along the - line in the figure. 1: Container side seam portion, 2: Laminate film, 3: Lid material, 4: Container body of the present invention, 5:
External container material, 6: Edge end, 7: Lid material,
8: Laminate film, 9: Filling contents, 1
0: Upper edge of side wall, 11: Curling machine, 1
2, 12': curling groove, 13: heating device,
14: Lifter, 16: Curling ring, 1
5: Chuck, 17: Curling wheel, 1
8: Joint tip of film layer and lid material, 19: Inner surface of container rim, 100: Conventional one-way container main body, 200: Conventional container rim, 300:
Step, 400: Communication hole, 500: Mouth edge of the container of the present invention.

Claims (1)

[Claims for Utility Model Registration] (1) A paper container body 4 whose entire inner surface is laminated with a thermoplastic plastic film 8; In a highly airtight paper container containing contents 9 in a container body 4, which is made of a lid material 7 made of plastic film and; b) Rolling the lid material 7 surface-bonded to the plastic film layer 8 of the container body 4 radially outward from the top of the body 4 and then downward from there;
After that, the film layer 8 and the lid material 7 are in surface contact with each other, but the film of the container body is The lid material 7 rolled together with the layer does not come into surface contact with the outer wall of the container body 4, and the film layer 8
The lid material 7 is characterized in that the joining tip 18 of the lid material 7 and the lid material 7 are simply in line contact with the inner surface 19 of the rim of the container.
A highly airtight paper container in which the container body is sealed without denting inside the main body 4. (2) The highly closed paper container according to claim 1, wherein the lid material is a film made of the same material as the thermoplastic plastic film laminated on the inner surface of the paper container body. (3) The highly airtight paper container according to claim 1, wherein the lid material is a film made of a material different from the thermoplastic plastic film laminated on the inner surface of the container body. (4) The paper container according to claim 2, wherein the thermoplastic film laminated on the inner surface of the paper container body and the thermoplastic film used for the lid material are both polyethylene.