JPH0891396A - Laminate tube container and manufacturing method thereof - Google Patents

Abstract

PURPOSE: To provide laminated tube containers that have no step due to lapping along a seam. CONSTITUTION: A laminated sheet comprising an intermediate layer 3 made of metal foil etc., and heat-sealable synthetic resin layers 4, 5 on both sides of the intermediate layer 3 is rolled to form a tube shell. The both ends 1, 2 of the sheet are cut aslant against its surface to form slant surfaces (a, b) for seaming. The slant surfaces (a, b) are heat-sealed integrally with the both ends of the intermediate layer 3 lapped to form a lapped part (D).

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 and a method for manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, as a material for an extruded tube container, as shown in FIG. 3, a heat-fusible synthetic resin such as polyethylene resin is provided on both surfaces of an intermediate layer 3 which is a gas barrier layer made of metal foil or the like. A laminated sheet formed by laminating layers 4 and 5 is used.

Further, when the laminated sheet is wound into a tube, both ends 1 and 2 of the joint are superposed and directly joined by thermal bonding (see FIG. 3).

[0004]

However, since the bonding ends of the above-mentioned laminated sheet are heat-bonded in a state where they are overlapped with each other, the overlapping portion of the seam becomes convex due to the step, so that the overlapping portion should be printed. However, there was a problem in printability and surface workability.

It is difficult to form a printed layer on the surface after manufacturing the tube container due to the step difference on the surface of the joint as described above. Conventionally, a laminated sheet preliminarily printed has been used. For this reason, there are large manufacturing restrictions, such as the need to specify the position of the laminated sheet by the printed position and the alignment when manufacturing the tube container from the printed laminated sheet.

Further, since the end face of the one end 1 is exposed to the outside, it may cause peeling of the foil between the layers of the laminated sheet from the end face, and the appearance may be bad.

Further, since the outer layer synthetic resin layer 4 and the inner layer synthetic resin layer 5 overlap and are heat-bonded to each other at the joint portion, it is difficult to obtain a strong adhesive strength when the inner layer resin and the outer layer resin are different. There was a constraint that it would be difficult to deal with it unless the same resin was used for the inner and outer layers. Therefore, selection of the synthetic resin of the inner layer according to the contents has been restricted.

The present invention has been made in view of the above conventional problems, and an object of the present invention is to provide a laminated tube container in which a step due to an overlapping portion of a joint is eliminated.

[0009]

In order to achieve the above object, the laminated tube container of the present invention is formed by laminating a heat-fusible synthetic resin layer on both surfaces of an intermediate layer made of a metal foil, a plastic film or the like. The jointed both ends for forming the body part of the tube by winding the laminated sheet formed in advance are cut obliquely to the surface in advance to form an inclined surface, and the inclined surfaces of the joined both ends are formed at both ends of the intermediate layer. It is characterized in that they are manufactured by superposing them along the inclined surface so that overlapping parts can be formed, and then integrally bonding them by thermal bonding. The length of the overlapping portion of the intermediate layers in this joint is 0.5 mm or more.

[0010]

In the laminated tube container of the present invention, there is no step because the inclined surfaces at both ends of the joint are superposed so that the overlapping portions at both ends of the intermediate layer are overlapped and then integrally joined by thermal bonding. A joint with a substantially smooth surface can be obtained. Therefore, there are no inconveniences in printability, surface workability, etc., and there is no problem of peeling between layers from the end face or appearance. Further, it is possible to obtain a tubular body having a sufficiently large tearing strength while only joining the inclined surfaces to each other.

Further, since the outer layer and the inner layer of the laminated sheet are integrally joined to each other, strong joining can be achieved even if the resins of the inner layer and the outer layer are different.

Further, since the intermediate layer which is the gas barrier layer has an overlapping portion at the joint portion, the gas barrier property of the resulting tube is not deteriorated.

[0013]

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

FIGS. 1 and 2 show an embodiment of the present invention. FIG. 1 is a cross-sectional view showing a state before joining both end portions of a laminated sheet for forming a tube body portion. FIG. 6 is a cross-sectional view showing a state after the joining.

The laminated tube of the present invention, as shown in FIG. 3, has a basic layer structure of the laminated sheet, which is the material thereof, in which both surfaces of the intermediate layer 3 which is a gas barrier layer are heat-fusible. It is a laminated sheet having a structure in which resin layers 4 and 5 are bonded together.

As the intermediate layer 3, a material having a gas barrier property such as a metal foil such as an aluminum foil, a metal or metal oxide vapor deposition film, an inorganic material or an inorganic oxide vapor deposition film, etc. is used.

The heat-fusible synthetic resin layers 4 and 5 are heat-bondable polyester, polyethylene (P
Resins such as E), polyacrylonitrile, and ethylene-vinyl alcohol copolymer are used. In the laminated tube container of the present invention, the resins used for the outer layer and the inner layer do not necessarily have to be the same, and different resins can be used for the inner layer and the outer layer. Depending on the type of contents filled in the tube container, it is necessary to use a material that does not adversely affect the contents of the inner layer. For example, PE can be used for the outer layer and different resins such as polyester can be used for the inner layer. . Each of the heat-fusible synthetic resin layers 4 and 5 does not have to be a single layer, and may have a multilayer structure in which a plurality of resin layers are laminated.

The laminated sheet used for the laminated tube container of the present invention is constructed as described above, and the joint ends 1 and 2 for winding the laminated sheet to form the body of the tube are shown in FIG. As shown, it is cut obliquely to the surface beforehand to form inclined surfaces a and b. The cutting angle is not particularly limited as long as it is an acute angle.

As described above, the inclined surfaces a and b of the adhesive both end portions 1 and 2 which are cut obliquely to the surface in advance are displaced along the inclined surface so that the overlapping portion D of both end portions of the intermediate layer 3 is formed. After superimposing so that they can be joined, both ends 1 and 2 of the joining are joined by applying appropriate heat and pressure. The overlapping portion D at both ends of the intermediate layer 3 may be of any degree as long as it does not deteriorate the gas barrier property of the tube, but the overlapping portion D is preferably 0.5 mm or more in terms of the adhesive strength of the joint portion.

Then, the outer surface side end surface of the inclined surface a of the end portion 1 of the laminated sheet overlaps with the outer layer of the end portion 2, and the inner surface end surface of the inclined surface b of the end portion 2 overlaps with the inner layer of the end portion 1. Then, they are integrally bonded by thermal bonding (see FIG. 2). Therefore, a joint having no step and a substantially smooth surface can be obtained, and a strong joint can be obtained even if the resins of the inner layer and the outer layer are different. It should be noted that both end portions 1, 2 of the laminated sheet are joined together.
Although the length of the overlapping portion D of the intermediate layer 3 varies depending on the position where the intermediate layers 3 are joined, even if the length of the overlapping portion D of the intermediate layer 3 is slightly different, the gas barrier property is not significantly affected.
Since the precision with respect to the position where the joining ends 1 and 2 are joined does not have to be so high, the manufacturing is easy.

Detailed examples will be described below.

A polyethylene terephthalate film (thickness: 12 μm) having a thickness of 12 μm and a silicon oxide vapor-deposited layer (400 Å) provided on the inside of the intermediate layer, with a urethane adhesive interposed, a urethane anchor coat layer, Extruded low density polyethylene layer (thickness 50
μm), and an inner layer made of extruded low density polyethylene was laminated.

On the other hand, a urethane anchor coat layer is interposed outside the intermediate layer, and a melt extruded low density polyethylene layer (thickness 20 μm) and a white polyethylene film (thickness 1
00 μm), melt extruded low density polyethylene layer (thickness 2
0 μm) and an outer layer made of antistatic low-density polyethylene were laminated to form a laminated sheet of a tube container.

Next, both ends of the laminated sheet were obliquely cut at an angle of about 40 degrees to form an inclined surface. Then, the inclined surfaces were polymerized, heated from both sides to form a joint, and a tubular body was manufactured.

The joint surface of this tubular body was smooth and had a beautiful appearance without white stripes.

The tear strength of this joint is 7-8.
The strength was such that kgf / 15 mm was sufficient to replenish the contents and allow storage.

Further, with the above-mentioned structure, the joint portion was formed by shifting the inclined surface so that the overlapping of the intermediate layers in the joint portion was 1.0 mm, and a tubular body was manufactured. The tear strength of this joint was 8 kgf / 15 mm.

With the above structure, the joint portion was formed by shifting the inclined surface so that the overlap of the intermediate layers in the joint portion was 0.3 mm, and a tubular body was manufactured. The tear strength of this joint was 5 kgf / 15 mm.

[0029]

As described above in detail, according to the laminated tube container of the present invention, the inclined surfaces of the joining ends of the laminated sheets, which are cut obliquely in advance, have the overlapping portions of the intermediate layers of the laminated sheets. Since they are superposed as much as possible and then integrally joined by heat bonding, a joint having a smooth surface can be obtained without the step of the joint as in the conventional case.

In addition, since the outer layer and the inner layer at both ends of the laminated sheet are integrally joined together, a strong joint can be obtained even if the resin of the inner layer is different from the resin of the outer layer. Different resins can be used.

Further, since the intermediate layer, which is the gas barrier layer, has an overlapping portion at the joint, there is no inconvenience that the gas barrier property of the tube is lowered.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a state before joining of both joining ends of a laminated sheet for forming a body of a tube.

FIG. 2 is a cross-sectional view showing a state after joining both joined ends of a laminated sheet for forming a body of a tube.

FIG. 3 is a cross-sectional view of a joint portion of a conventional tube.

[Explanation of symbols]

 1, 2 joining end part 3 intermediate layer 4,5 thermal fusion bonding synthetic resin layer a, b inclined surface D overlapping part of intermediate layer

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Claims (2)

[Claims] 1. A laminated sheet formed by laminating a heat-fusible synthetic resin layer on both surfaces of an intermediate layer made of metal foil or the like is wound, and both ends of a joint for forming a body part of a tube are previously surfaced. The slanted surface is cut diagonally with respect to the slanted surface, and the slanted surfaces at both ends of the joint are superposed along the slanted surface so as to form an overlapping portion at both ends of the intermediate layer, and then integrated by heat bonding. A laminated tube container characterized by being joined to. 2. A laminated sheet formed by laminating a heat-fusible synthetic resin layer on both surfaces of an intermediate layer made of metal foil or the like is wound, and both ends of a joint for forming a body part of a tube are previously surfaced. The slanted surface is cut diagonally with respect to the slanted surface, and the slanted surfaces at both ends of the joint are shifted so that the overlapping portions at both ends of the intermediate layer are formed, and the slanted surfaces are superposed along the slanted surface before heat treatment. A method for manufacturing a laminated tube container, which is integrally bonded by adhesion.