JP3240707B2 - Multilayer sheet for containers - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multilayer sheet for a draw-formed container which is mainly made of paper. In particular, if a highly volatile insect repellent, deodorant, fragrance, etc. are stored in solid form,
Alternatively, the present invention relates to a laminated multilayer sheet used for molding a container for accommodating a sheet or the like impregnated with the above substance.

[0002]

2. Description of the Related Art Conventionally, a multilayer sheet formed by coating and laminating a plastic such as polyethylene on both sides of a paper and laminating and forming a metal by vapor deposition is formed by press molding,
It has been used in a wide range as a container formed into a cup shape, tray shape, or the like by draw forming such as vacuum forming or pressure forming.

[0003]

However, when a conventional multi-layer sheet mainly composed of paper is formed into a container by drawing, the formability of the multi-layer sheet is poor, and the multi-layer sheet cannot be drawn directly. . Therefore, in order to facilitate drawing, the multi-layer sheet is heated and the step of bending the multi-layer sheet is performed, that is, the step rolling step is performed at least once, and then drawing is performed to form a container. Since the number of molding steps is increased, and the container is molded after the step rolling process, streaks may occur on the wall surface of the container. Further, if the multilayer sheet is formed deep without going through the step-rolling step, cracks and the like are formed on the wall surface, and the appearance of the container is poor, and it may not be possible to use the container as a container. For this reason, in the case of a container using a multilayer sheet mainly composed of paper, a fine pattern cannot be formed in the container, and a deep container having a high drawing ratio and a large depth cannot be formed. In multilayer sheets that do not use paper as the main component,
Although it is possible to solve the above-mentioned problems caused by drawing, if the multilayer sheet is entirely formed of plastic, an environmental problem such as disposal occurs.

The present invention has been made in view of the above-mentioned problems, and has reliable contents resistance, barrier properties, etc., can form a fine pattern, has a deep depth, can easily and surely draw a container. Provide a multilayer sheet.

[0005]

The feature of the present invention is that a multi-layer sheet for a container for forming a deep drawing container mainly composed of paper is provided.
Outer layer of the container that suppresses deformation due to deep drawing
Polyolefin resin layer, softwood pulp and broadleaf
Deep drawing with the mixing ratio of tree pulp being 7: 3 to 10: 0
Container with a basis weight of 200 g / m2 or more to prevent paper breakage at the time
Adhesion with paper layer to give rigidity and polyolefin resin
Layer and gas barrier aluminum with a thickness of 5 to 50 μm
Layer and polyethylene for imparting deep drawability and shape retention
Provides terephthalate layer with content resistance and adhesion
Laminate the thermoplastic synthetic resin layer as the inner layer of the container in this order
It is a multilayer sheet for containers characterized by comprising .

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to embodiments. FIG. 1 is a cross-sectional view of an embodiment of the multilayer sheet for containers of the present invention, and FIG. 2 is a perspective view of the container of one embodiment formed from the multilayer sheet of the present invention.

The multilayer sheet for containers according to the present invention comprises a polyolefin resin (1), paper (2), polyolefin resin (3), aluminum (4), an adhesive layer (5), polyethylene terephthalate (6), an adhesive layer ( 7) and a thermoplastic synthetic resin (8). The thickness of the laminated synthetic resin film is optimally 300 to 500 μm for moldability, but it is also possible to change the thickness of the container multilayer sheet depending on the shape of the molded product.

In this embodiment, the polyolefin resin is
All use polyethylene. Polyethylene has high strength and high impact resistance, so it does not deform the wall of the container during drawing, and because of its high water resistance, it does not deform due to moisture during use of the molded container. Because of its high adhesiveness, it is provided for the adhesive layer of the container as a thermal adhesive for the container. The thickness of the polyethylene (1) in this embodiment is 20 μm, and non-oriented polyethylene is used as the polyethylene. Also, uniaxially stretched polyethylene can be used.

In the present invention, all virgin paper obtained by mixing softwood pulp and hardwood pulp in a ratio of 7: 3 to 10: 0 is used. This is because the softwood pulp has a longer fiber than the hardwood pulp, and thus is hard to be split by pulling. Paper is used for imparting rigidity to a container formed from the multilayer sheet for containers of the present invention to improve impact resistance. The basis weight of the paper used in the present invention is 200 (g / g).
m ² ) or more is required. This is based on a basis weight of 200 (g / m
^If it is less than ² ), the paper will break during drawing. The paper (2) used in this example is a processed paper having a basis weight of 320 g / m ² . Further, when a thermoplastic resin is blended with paper, the possibility of tearing and deformation of the paper during molding is reduced even when drawing is performed on paper blended with the thermoplastic resin. This is because the fibers of the paper and the fibers of the thermoplastic resin are entangled with each other.
Thermoplastic resins that can be used include polyethylene, polypropylene, polystyrene, polyvinyl acetate and the like.

The polyethylene (3) provided between the paper (2) and the aluminum (4) is provided as an adhesive layer because of its good adhesiveness. The polyethylene between the paper and the aluminum preferably has a thickness of 15 to 100 μm. This is because when drawing is less than 15 μm,
This is because it may not serve as an adhesive layer. Further, if the thickness exceeds 100 μm, the above effects cannot be obtained, and it becomes difficult to draw. The thickness of the polyethylene (3) in this example is 22 μm, and non-oriented polyethylene is used. Further, uniaxially stretched polyethylene can also be used.

Aluminum is a gas barrier property, a shape preserving property, a concealing property of a container formed from the container multilayer sheet of the present invention.
It is provided for ultraviolet blocking properties and the like. Preferably, the aluminum has a thickness of 5 to 50 μm. This is because if the thickness is less than 5 μm, it is difficult to maintain the above-described properties of aluminum. Also, 50μ
This is because no effect other than the above is produced even if m is exceeded.
The thickness of the aluminum (4) in this embodiment is 7 μm.

As the adhesive used for the adhesive layer, a two-component curable adhesive which can be adhered to the surfaces of the adhesive layers (5) and (7) to which the respective adhesive layers are adhered is used.

Polyethylene terephthalate has high impact resistance, high heat resistance, and good moldability with aluminum. Therefore, polyethylene terephthalate improves the shape retention of a container formed from the multilayer sheet for containers of the present invention, and is useful for drawing. To improve molding suitability at
It is provided to prevent aluminum from cracking during molding and to prevent paper tear during molding. It is desirable that the polyethylene terephthalate has a thickness of 12 to 25 μm. If the thickness is less than 9 μm, cracking or tearing of aluminum or paper may occur during drawing, or the above-mentioned properties of polyethylene terephthalate may not be obtained. On the other hand, when the thickness exceeds 25 μm, drawing becomes difficult. The thickness of the polyethylene terephthalate (6) of this embodiment is 12 μm,
Axial stretched polyethylene terephthalate is used.

The thermoplastic synthetic resin (8) used for the innermost layer is polyethylene, polyethylene terephthalate, or the like, which has improved content resistance and good thermal adhesion. It is desirable that the thermoplastic synthetic resin (8) has a thickness of 40 to 100 μm. If it is less than 40 μm, the film may be cracked or uneven in thickness during drawing, or may not function as a sealant material. Further, even if the thickness exceeds 100 μm, an effect higher than the above effect does not occur. The thermoplastic synthetic resin (8) of this embodiment uses polyethylene and has a thickness of 6 mm.
0 μm, and is a non-stretched polyethylene.

The order of laminating the synthetic resin sheets and forming the multilayer sheet for the container is to laminate the polyethylene on both sides of the paper.
Separately, polyethylene terephthalate and aluminum are laminated, and then polyethylene is laminated on the polyethylene terephthalate surface. Next, the aluminum surface and the polyethylene surface of each of the above-mentioned multilayer sheets are laminated together. The lamination method on each synthetic resin sheet surface is such that polyethylene (1) and paper (2) are hot melt laminated. Paper (2) and polyethylene (3) are hot melt laminates. Polyethylene (3) and aluminum (4) are hot melt laminates. Aluminum (4) and polyethylene terephthalate (6) are dry laminates. Polyethylene terephthalate (6) and polyethylene (7) are dry laminates.

The drawing used in the present invention is a method in which a multilayer sheet for a container is pressed against a mold while being softened by heating. The multilayer sheet for containers may be heated by a method such as an infrared heater. In the present invention, heating is performed at about 20 to 60 degrees, hot pressing is performed, and then drawing is performed. The draw forming in the present embodiment is a method (press forming method) in which a male mold (press) is pressed from the opposite side of the mold to press the multilayer sheet for containers against a female mold.

In Examples and Comparative Examples, multilayer sheets for containers laminated by the above method are used. <Embodiment> The draw forming method of this embodiment is a press forming method. The molding speed is 50 seconds, the molding heating temperature is 80 degrees, the humidification is performed from both sides, and the state of the molding container is pressed 10 times in each of the examples and comparative examples after 36 hours under the conditions of a temperature of 40 degrees and a humidity of 0%. Mold, pour turpentine oil into the protrusions of the molded container, measure the state of leakage to the outside to determine the state of leakage, and measure the appearance of the container by measuring the cracks in the side walls of the container after press molding. judge.

The multi-layer sheet for a container of this embodiment is made of polyethylene 20 μm / processed paper: about 179 μm (basis weight 230 g /
m ² ) / polyethylene 22 μm / aluminum 7 μm /
It is laminated with a thickness of adhesive layer / polyethylene terephthalate 12 μm / adhesive layer / polyethylene 60 μm, and has a total thickness of 300 μm.

Example 2 The container multilayer sheet of Example 2 was made of polyethylene 20 μm / processed paper: 369 μm (basis weight 320 g / m ² ) / polyethylene 22 μm / aluminum 7 μm / adhesive layer / polyethylene terephthalate 12 μm.
m / adhesive layer / polyethylene 60 μm in this order, with a total thickness of 490 μm.

Comparative Example 1 The container multilayer sheet of Comparative Example 1 was made of polyethylene 20 μm / processed paper: 168 μm (basis weight 150 g / m ² ) / polyethylene 18 μm / aluminum 15 μm / adhesive layer / polyethylene terephthalate 9 μm.
m / adhesive layer / polyethylene laminate of 60 μm and a total thickness of 290 μm.

<Comparative Example 2> The container multilayer sheet of Comparative Example 2 was laminated on polyethylene 20 μm / processed paper: 421 μm (basis weight 340 g / m ² ) / polyethylene 20 μm / aluminum 9 μm / adhesive layer / polyethylene 40 μm. And a total thickness of 510 μm.

The multilayer sheet for containers of each of the above Examples and Comparative Examples is provided with a flange around the flange, a projection having a depth of about 3 mm and a radius of about 3 mm and a height of about 1.5 mm on the pressed bottom (9). Then, press molding is performed so as to provide a volatilization hole (10) for the content. Table 1 shows the results of press molding.

[0023]

[Table 1]

[0024]

As described above, the multilayer sheet for a container according to the present invention has the above-mentioned structure, and as shown in Table 1, a multilayer sheet containing paper as a layer cannot be formed by a conventional drawing method. A multi-layer container having a shape and a high height can be formed.

Since the multilayer sheet for a container is warmed before forming and hot pressed to increase the extensibility of PET in the Al / PET layer structure, the formability of PET is improved.
Even with PET in contact with 1, a container having a fine shape that could not be obtained conventionally can be formed. Also, A
Since the 1 / PET layer structure is laminated by lamination,
When forming a multilayer sheet for containers, P
It can be resolved by ET.

[Brief description of the drawings]

FIG. 1 is a sectional view of an embodiment of the present invention.

FIG. 2 is a perspective view of a container formed in an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Polyolefin resin 2 ... Paper 3 ... Polyolefin resin 4 ... Aluminum 5 ... Adhesive layer 6 ... Polyethylene terephthalate 7 ... Adhesive layer 8 ... Thermoplastic synthetic resin 9 ... Projection 10 ... Volatilization hole

Claims (1)

(57) [Claims] 1. A container for forming a deep drawing container mainly composed of paper.
A multilayer sheet that suppresses deformation due to deep drawing
Polyolefin resin layer as outer layer of container and softwood pal
And hardwood pulp at a mixing ratio of 7: 3 to 10: 0
Weight less than 200g / m2 to prevent paper breakage during drawing
Paper layer that gives the above container rigidity and polyolefin resin
And a gas barrier of 5 to 50 μm thickness
Minium layer and poly for deep drawing formability and shape retention
Ethylene terephthalate layer and content resistance and adhesion
The thermoplastic synthetic resin layer as the inner layer of the container
A multilayer sheet for containers characterized by being sequentially laminated .