JPH05330568A - Material forming hermetically sealing lid for opening of vessel - Google Patents

Abstract

PURPOSE:To obtain a material for a hermetically sealing lid for the opening of a container which makes the contents visible, is capable of being burnt easily, and hardly permits the contents to be affected in quality by superposing a resin film of the ethylene series on one surface of thermoplastic polyester film, which has been coated with silica by vapor deposition, with an adhesive copolymer film therebetween for sticking them together. CONSTITUTION:This is a maternal for hermetically sealing lid for the opening of a container which is obtained by superposing a resin film of the ethylene series 5 on one surface of thermoplastic polyester film 1, which has been coated with silica by vapor deposition, with an adhesive copolymer film 4 therebetween for sticking them together. Though it retrogrades some what in transparency, this laminated film makes good lids with advantages that the contents are visible therethrough, the air and aqueous vapor permeating the lid from outside is much less in amount than ever, and the adhesion to a container can be effected easily by melt-attachment of the thermally fusible film. A resin of the ethylene series is suitable for the melt-attaching underside film and an adhesive consisting of a copolymer of ethylene and ethyl acrylate is suitable for use between the underside film and the silica-coated film.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lid member for sealing an opening of a container.

[0002]

2. Description of the Related Art A lid material for sealing an opening of a container has been used as an inner lid of a can for closing foods such as tea and baked seaweed in a metal can.

Metal cans have been used for a long time as containers for foods such as tea and roasted seaweed which are deteriorated when exposed to air. Since metal cans do not allow air to pass through at all, they are certainly suitable for containing and storing foods as described above for a long time. However, metal cans have the drawback that the contents cannot be seen from the outside and that they can easily rust.

As a transparent container, there is a glass container, but the glass container has a drawback that it is easily broken. As a transparent and hard-to-break container, there is a synthetic resin container, but since the synthetic resin container allows the permeation of air and water vapor, it will deteriorate the food during storage, and thus the food cannot be stored for a long time. Has a drawback. Therefore, an attempt has been made to provide a container for food storage by reducing the air and water vapor permeability of the synthetic resin as much as possible by combining the synthetic resins or other materials. As a result, laminated films or sheets of various synthetic resins have been provided and used to make food storage containers. In such a synthetic resin container, it is necessary to seal the opening.

In the case of metal cans, metal sheets or foils have heretofore been used to close the opening of the can as an inner lid. A heat-melting adhesive was applied to the surface of the metal thin plate or the metal foil, and when the opening was closed, the adhesive was heated and melted to be welded to the mouth of the can. Further, also in the above-mentioned synthetic resin container, a similar metal foil is often used to close the opening.

However, if a metal foil is used for the lid material for sealing the opening of the container, the contents of the container cannot be seen through the lid. In addition, the lid material coated with an adhesive for welding was difficult to dispose of after use.
This is because the lid material coated with the adhesive is not easily rusted or corroded, and cannot be easily removed by baking it. Therefore, the appearance of a lid material that can be easily incinerated, is transparent, and is difficult to pass air and water vapor has been desired.

[0007]

DISCLOSURE OF THE INVENTION The present invention is originally transparent, allows the contents to be seen from the outside, and is easy to incinerate.
Moreover, it is an object of the present invention to provide a lid material for opening sealing in which the permeability of air and water vapor is small and the quality of the contents is not easily altered.

[0008]

The inventor of the present invention has found that a silica vapor-deposited film made by vapor-depositing silica on a thermoplastic polyester film can be easily converted into ash by incineration and, at the same time, that air and water vapor We paid attention to the small transparency. Moreover, this silica-deposited film can be made almost transparent if the degree of oxidation of silica is appropriately adjusted.
Further, it has been found that the permeability of oxygen and water vapor can be further reduced, which is suitable for use as a sealing lid material. Therefore, the present inventor has attempted to make a lid material for sealing the opening of a container by using a vapor-deposited silica film. However, the silica vapor deposition film alone cannot be used as a lid material.

The present inventor has considered that the silica layer of the silica vapor deposition film is laminated with a heat-welding backside film via a crocodile adhesive to form a laminated film, and the laminated film is used as a lid material. In this way, the laminated film is slightly less transparent, but it is still possible to see something through the laminated film and to further reduce the amount of air and water vapor permeating from the surface, Further, they have found that they can be easily adhered to a container by welding a heat-welding film, and thus they are suitable as a lid material.

The present inventor has further studied the adhesive and the heat-welding film necessary for forming the above structure. As a result, they have found that an ethylene resin such as a copolymer of ethylene and vinyl acetate is suitable as the heat-welding back film. Further, they have found that a copolymer of ethylene and ethyl acrylate is suitable as the adhesive between the back film and the silica vapor deposition film. The present invention was made based on such knowledge.

The gist of the present invention is a lid material for opening and sealing a container, which is obtained by laminating an ethylene resin film on one surface of a silica-deposited thermoplastic polyester film via an adhesive copolymer film. To do.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An example of the embodiment of the lid material for sealing the opening of a container according to the present invention will be described below with reference to the drawings. FIG. 1 is a partially cutaway enlarged perspective view of a lid member for sealing an opening of a container according to the present invention. FIG. 2 is a perspective view of a container provided with a lid member for opening sealing according to the present invention. Figure 3
[Fig. 3] is an enlarged cross-sectional view showing a connecting portion with a lid member in the container shown in Fig. 2.

A lid member A for sealing an opening of a container according to the present invention
As shown in FIG. 1, a thermoplastic polyester film 1, an ink layer 2 printed on the film 1, a silica layer 3 vapor-deposited on the film 1 from above, and a film 4 of an adhesive copolymer. And an ethylene-based resin film 5 are laminated together.

As shown in FIG. 2, the above-mentioned lid member A is previously cut into a shape that can just close the opening of the container B, and is placed at a position to close the opening of the container. At that time, the lid member A is arranged with the ethylene-based resin film 5 facing the crocodile. After that, the lid material is heated at the contact portion C between its peripheral edge and the container opening to be welded to the container, and the opening is closed. Thus, the lid member A according to the present invention is used to close the opening of the container B.

In the cover material A, the thermoplastic polyester (hereinafter abbreviated as PET) constituting the thermoplastic polyester film is a divalent aliphatic alcohol or alicyclic group in an aromatic dibasic acid. It is a chain polymer composed of ester obtained by reacting alcohol. Terephthalic acid was often used as the aromatic dibasic acid, and ethylene glycol was often used as the divalent aliphatic alcohol. Therefore, a typical example of PET is polyethylene terephthalate. As the alicyclic dihydric alcohol, 1,4-cyclohexanedimethanol was generally used, but it is not used alone, but is used as a mixture with the aliphatic alcohol. PET which uses a part of such alicyclic alcohol has a characteristic that it is easily processed. In the present invention, such a film made of PET which can be easily processed can also be used.

The PET film is preferably biaxially stretched to orient the molecules. Its thickness is 10
It is preferably ˜15 μm, but may be higher. In addition, the PET film may have a printed surface. When printing is performed, it is preferable to perform silica vapor deposition described below on the printing surface.

In the present invention, a PET film having silica deposited thereon is used. For vapor deposition, for example, the surface of silicon monoxide is uniformly scanned with an electron beam to sublimate silicon monoxide,
Propagating sublimed silicon monoxide toward the PET film in an oxygen atmosphere, cooling the back surface of the PET film with a cooling drum, and depositing on the PET film to form a silicon oxide film in the form of SiO _x. Done by
There is also a method of using a plasma of SiO ₂ instead of the electron beam. In any case, _X in SiO X is 1.5
It is said that it must be maintained within the range of to 1.8. The thickness of the SiO _X is preferably set to 400 to 1000 angstroms.

When X is in the range of 1.5 to 1.8,
SiO _X has ductility and has low permeability to oxygen and water vapor. At this time, SiO _x is chemically inert, is not attacked by acids, alkalis and organic solvents, and is stable to high temperature steam such as 121 ° C. Furthermore, SiO _x has a high affinity with inks and adhesives, and printing and lamination can be easily performed. Therefore, P deposited with silica
The ET film itself is suitable for applications where it comes into direct contact with food.

The silica vapor deposition film described above is already commercially available. For example, it is sold under the trade name of MOS by Oike Industry Co., Ltd. In the present invention, such a commercially available silica vapor-deposited PET film can be used.

In the present invention, an adhesive copolymer film is attached to one surface of the above silica vapor-deposited PET film. Among the surfaces of the silica vapor-deposited PET film, it is preferable to bond them on the silica vapor-deposited surface. As the adhesive copolymer, it is preferable to use a copolymer of ethylene and ethyl acrylate (hereinafter, abbreviated as EAE). The EAE may contain other third component besides ethylene and ethyl acrylate. As the third component,
Maleic anhydride is especially preferred.

Therefore, the preferred adhesive copolymer for use in the present invention is a binary copolymer of ethylene and ethyl acrylate, and a terpolymer in which maleic anhydride is added. .. As the binary copolymer, for example, one sold by Sumitomo Chemical Co., Ltd. under the trade name of Bondyne, or one sold by Showa Denko KK under the trade name of ADTEX can be used. As the terpolymer, for example, one sold by Mitsubishi Petrochemical Co. under the trade name of Modic or one sold by Mitsui Petrochemical Co. under the trade name of Admer can be used. The thickness of the adhesive copolymer film is preferably 5 to 50 μm.

In the present invention, an ethylene resin film is laminated on the above-mentioned adhesive copolymer film.
The ethylene-based resin film is, for example, a copolymer of ethylene and vinyl acetate (hereinafter, abbreviated as EVA), and is linear low density polyethylene. It is desirable that these are bonded by heat welding. As EVA, those sold under the trade name of Everflex by Mitsui DuPont Polychemical Co., Ltd. can be used, and as linear low density polyethylene, those sold under the trade name of Sumikasen-L by Sumitomo Chemical Co., Ltd. can be used. Can be used. The thickness is preferably 5 to 50 microns, but may be more than that.

In the lid member according to the present invention, an adhesive copolymer film and an ethylene resin film are extrusion-molded, respectively, and a silica vapor-deposited PET film is adhered to the film to form a laminated film.
Cut this laminated film according to the opening shape of the container,
This is used as a lid material for sealing the opening of the container. At this time, as shown in FIG. 2, it is desirable to additionally attach the knob D. As for the knob D, as shown in FIG. 2, the lid material A is the container B.
When it is welded to the container B, if it is projected from the opening of the container B, it serves as a clue when the lid material A is peeled from the container B, and therefore peeling is facilitated.

In the above description, the term film has been used for various synthetic resins. A film generally refers to a film having a small thickness, and a film having a large thickness is called a sheet to distinguish it from a film. However, there is no particular limitation on the thickness of the film in the present invention, and since it does not matter if the film thickness is increased, when the film is referred to in the present invention,
It also includes a sheet.

The lid material according to the present invention may include other films in addition to the above-mentioned films. For example, in FIG. 1, a copolymer film of ethylene and vinyl alcohol (hereinafter referred to as EVA film) is sandwiched between the adhesive copolymer film 4 and the ethylene resin film 5, and the laminate shown in FIG. The films can be designated as films 1, 2, 3, 4 from above, EVA films, 4 and 5 from the top.

The lid material for sealing the opening of the container according to the present invention is
It can be used for containers containing various foods. For example, it is suitable as a lid material for a container containing curry, stew, butter, cheese, pudding, jelly, yokan, prepared foods, seaweed, tea, seasonings, juices and other processed foods. This lid member, after the above-mentioned food is put in a container, the ethylene resin film in it is directed toward the container and placed at a position to close the opening of the container, and the peripheral edge of the lid member and the opening peripheral edge of the container are placed. It is attached to a container by heating and welding.

[0027]

According to the present invention, P deposited with silica is deposited.
Since the ethylene resin film was attached to one surface of the ET film via the adhesive copolymer film to form a lid material, everything else is transparent except that the ethylene resin is translucent. In addition, the lid material is nearly transparent, so the contents can be seen from the outside through the lid. Also,
Since the lid material contains a PET film on which silica is vapor-deposited, the vapor-deposited layer of silica prevents the permeation of air and water vapor, thus making it difficult for the contents to be altered and being reinforced by the PET film. Therefore, it is tough despite its thin thickness. Further, since the ethylene resin film is exposed on one surface of this lid member, the container is closed with the ethylene resin film facing the container and the opening of the container is made of ethylene resin. If this is done, the lid material can be heat-welded to the container, which is suitable for sealing the container. Furthermore, since the PET film is tough as described above, the ethylene-based resin film is also tough, and since both films are rich in flexibility, this lid material is suitable for peeling from the container, Therefore, it is suitable as a lid material for a container that can be easily peeled off when opened. In addition, since this lid material is made of only harmless materials, there is no risk of contaminating the food even if it comes into contact with the food for a long time. Therefore, the lid material according to the present invention is suitable as a lid for a container containing a food as exemplified above. In addition, when this lid material is incinerated, PET, adhesive copolymer and ethylene resin are all burned off, leaving only silica, but silica is a non-toxic powder like sand, so it is not used. After that, it can be easily disposed of by incineration. Further, since the lid member is transparent, it can be colored in any color, and thus becomes transparent and beautiful. The present invention provides such benefits.

[Brief description of drawings]

FIG. 1 is a partially cutaway enlarged perspective view of a lid member for sealing an opening of a container according to the present invention.

FIG. 2 is a perspective view of a container provided with a lid member for sealing the opening of the container according to the present invention.

FIG. 3 is an enlarged cross-sectional view showing a connecting portion of a lid member in the container shown in FIG.

[Explanation of symbols]

 A Lid for sealing the opening of the container 1 Thermoplastic polyester film 2 Printed ink layer 3 Evaporated silica layer 4 Adhesive copolymer film 5 Ethylene resin film

Claims (4)

[Claims] 1. A lid member for sealing an opening of a container, which is obtained by laminating an ethylene resin film on one surface of a thermoplastic polyester film vapor-deposited with silica via a film of an adhesive copolymer. 2. The lid material for opening and sealing a container according to claim 1, wherein the adhesive copolymer is a copolymer of ethylene and ethyl acrylate. 3. The adhesive copolymer is characterized by being copolymerized by further adding maleic anhydride.
A lid member for sealing an opening of a container according to claim 2. 4. The container according to claim 1, wherein the ethylene-based resin is a copolymer of ethylene and vinyl acetate or linear low density polyethylene. A lid material for sealing the opening of.