JP3337091B2 - Laminated tube container - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminated tube container in which a cylindrical container body is formed of a flexible laminated sheet and used for packaging paste-like contents. The present invention relates to a laminated tube container having excellent joining strength at a portion.

[0002]

2. Description of the Related Art Various materials have been disclosed as materials for the above-mentioned laminated tube container. One example is an aluminum foil suitable for protecting the contents on both sides and a heat-resistant material such as polyethylene as an outer layer. 2. Description of the Related Art A multi-layer laminated sheet obtained by laminating a fusible synthetic resin film, a paper layer, and the like is known.

[0003] Although a laminated sheet using such a paper layer has a moderate stiffness and dimensional stability, the paper layer is hygroscopic, so that the interlayer of the laminated sheet may peel off from the end face of the joint that appears on the outside. There is a problem that the container is liable to be damaged when dropped and has a low strength against impacts such as dropping.

Therefore, it has been proposed to use a biaxially stretched plastic film such as polyester or nylon having a high strength in place of the paper layer (Japanese Patent Application Laid-Open No. 62-191144).
No., Japanese Utility Model Publication No. 62-18450).

In the conventional structure described in the above publication, as shown in FIG. 2, heat-fusible synthetic resin layers 3 and 4 such as polyethylene are provided as inner and outer layers on both surfaces of an intermediate layer 1 made of aluminum foil or the like. A laminated sheet having a biaxially stretched polyester (for example, polyethylene terephthalate) film 6 disposed on the outer layer side of the intermediate layer 1 in place of the conventional paper layer is wound, and the joined both end portions are overlapped with each other and thermally bonded as it is. Are joined. In the drawing, reference numeral 5 indicates a joint.

FIG. 3 similarly shows a case where a biaxially stretched nylon film 7 is arranged on the outer layer side of the intermediate layer 1 instead of the conventional paper layer.

[0007]

However, according to the above-mentioned conventional structure, as shown in FIG. 2A and FIG. 3A, at the joint portion 5, the edge of the biaxially stretched polyester film 6 or nylon film 7 is formed. Has a structure protruding from the edge of the intermediate layer 1 such as an aluminum foil having a good barrier property. Therefore, in the case where the content filled in the tube container is a material having a strong permeability such as a fragrance, the permeated material directly reaches the polyester film 6 or the nylon film 7 without being shielded by the intermediate layer 1, and the adhesion of these film portions is performed. There is a problem of delamination due to a decrease in strength and insufficient bonding strength of the bonding portion 5.

The present invention has been made in view of the above-described conventional problems, and has as its object to reduce the bonding strength between layers of a laminated sheet and to cause insufficient bonding strength at a bonding portion as in the conventional case. It is an object of the present invention to provide a laminated tube container that does not have a sufficient strength and can secure sufficient strength.

[0009]

In order to achieve the above object, the laminated tube container of the present invention is obtained by laminating a heat-fusible synthetic resin film or the like as an inner or outer layer on both surfaces of an intermediate layer made of a metal foil or the like. In a laminated tube container in which the formed laminated sheet is wound to form the body of the tube by thermal bonding at the edges, the outer side of the intermediate layer of the laminated sheet is shrunk by heat during the thermal bonding via a polyethylene layer. To arrange a biaxially oriented polypropylene film,
At the joint of the laminated sheet, the polypropylene film shrinks due to heat during thermal bonding,
When the edge of the polypropylene film is viewed from the inner side of the container, the polypropylene film is located at a position recessed from the edge of the intermediate layer and has a structure shielded by the intermediate layer.

[0010]

The laminated tube container of the present invention is a biaxially stretched polypropylene film which is shrunk by heat at the time of heat bonding via a polyethylene layer to an outer layer side of an intermediate layer which is a gas barrier layer of a laminated sheet forming a tube body. Since the polypropylene film shrinks due to heat at the time of thermal bonding at the joint portion of the laminated sheet, when the edge of the polypropylene film is viewed from the container inner side, the edge of the intermediate layer Is also in the retracted position, and the structure is shielded by the intermediate layer. Therefore, even if the content is strong, the permeated material is sufficiently shielded by the intermediate layer and does not directly reach the polypropylene film. No problems such as lowering and insufficient joint strength at the joints occur. Therefore, necessary and sufficient strength can be secured.

[0011]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 1 shows an embodiment of the present invention and is a cross-sectional view showing a joint portion of a laminated sheet for forming a tube body.

The laminated tube container of the present invention is shown in FIG.
As shown in FIG. 3 and FIG. 3, the basic layer structure of the laminated sheet is a heat-fusible synthetic resin composed of multiple layers as inner and outer layers on both surfaces of the intermediate layer 1 which is a gas barrier layer. It is a laminated sheet having a structure in which layers 3 and 4 are bonded together. Further, a poly sheet is provided on the outer layer side of the intermediate layer 1 of the laminated sheet.
Biaxially oriented polypropylene film 2 via ethylene layer
Is arranged.

The intermediate layer 1 is made of a material having gas barrier properties, such as a metal foil such as an aluminum foil, a metal or metal oxide deposited film, an inorganic or inorganic oxide deposited film, and the like.

The heat-fusible synthetic resin layers 3 and 4 are made of a heat-bondable resin such as polyethylene (PE), polyacrylonitrile, and ethylene-vinyl alcohol copolymer. In the laminate tube container of the present invention, the resin used for the outer layer and the resin used for the inner layer do not necessarily need to be the same. For example, depending on the type of the contents to be filled in the tube container, it is necessary to use a material that does not adversely affect the contents of the inner layer. Therefore, different resins can be used for the inner layer and the outer layer. Each of the heat-fusible synthetic resin layers 3 and 4 does not need to be a single layer, and generally has a multilayer structure in which a plurality of resin layers are laminated.

The laminated sheet used in the laminated tube container of the present invention is constituted as described above. In order to wind the laminated sheet to form the body of the tube, it is necessary to overlap both ends of the joined sheet. Then, bonding is performed by applying appropriate heat and pressure. Both ends of the laminated sheet are integrally joined by this thermal bonding, and a joint 5 as shown in FIG. 1 is formed.

As shown at A in FIG. 1, at the joint 5, the edge of the biaxially stretched polypropylene film 2 is located at a position recessed from the edge of the intermediate layer 1 having good barrier properties. Thus, the structure is shielded by the intermediate layer 1.

A specific embodiment will be described below.

An ethylene-methacryl-acrylate (EMAA) film (thickness: 40 μm) and an extruded low-density polyethylene layer (thickness: 5 μm) are interposed between a 10 μm-thick aluminum foil intermediate layer and a urethane-based adhesive.
0 μm).

On the other hand, an EMAA layer (thickness 2) is formed outside the intermediate layer.
5μm), white polyethylene film (thickness 70μ)
m), melt-extruded low-density polyethylene layer (thickness 20μ)
m), biaxially stretched polypropylene film (thickness 20μ)
m), extruded low-density polyethylene layer (thickness 30 μm)
And antistatic low density polyethylene layer (thickness 35μm)
Are laminated to form a laminated sheet for a tube container.

Next, both ends of the laminated sheet were polymerized and heated from both sides to form a joint, thereby producing a cylindrical body. This was further processed into a tube container, filled with a highly permeable content such as a fragrance, and stored at room temperature for 10 days.

After storage, the joint was pulled up and down, and the peel strength was measured. The peel strength was not peeled, and it was strong enough to fill and store the contents. In addition, even if the content was filled after forming the tube container, the adhesive strength between the layers of the laminated sheet was high, and delamination did not occur at all.

In addition, a tube container having the above configuration and using a biaxially stretched nylon film (thickness: 15 μm) instead of the biaxially stretched polypropylene film was prepared and subjected to the same storage test as above. Peel strength is 30
The weight was 0 to 360 g.

[0024]

As described above in detail, according to the laminated tube container of the present invention, the adhesive strength between the layers of the laminated sheet forming the body of the tube as in the conventional case is reduced, and the joint strength of the joint is insufficient. Such a problem does not occur, and sufficient strength can be secured.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a joint of a laminated sheet according to one embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a joint portion of a laminated sheet according to a conventional example.

FIG. 3 is a cross-sectional view showing a joining portion of a laminated sheet according to a conventional example.

[Explanation of symbols]

 Reference Signs List 1 intermediate layer 2 biaxially stretched polypropylene film 3, 4 heat-fusible synthetic resin film 5 joint 6 biaxially stretched polyester film 7 biaxially stretched nylon film

Claims (1)

(57) [Claims] 1. A tube body formed by laminating a heat-fusible synthetic resin film or the like as an inner or outer layer on both surfaces of an intermediate layer made of a metal foil or the like, and winding the edge of the tube by heat bonding. A laminated tube container, wherein a polyethylene layer is formed on the outer layer side of the intermediate layer of the laminated sheet.
A biaxially stretched polypropylene film that shrinks due to the heat at the time of the heat bonding is disposed, and at the joint portion of the laminated sheet, the polypropylene film shrinks due to the heat at the time of the heat bonding, thereby forming an edge of the polypropylene film. Is a position retracted from an edge of the intermediate layer when viewed from the inside of the container, and has a structure shielded by the intermediate layer.