JPH05213337A - Multilayer paper container - Google Patents

Abstract

PURPOSE:To provide a multiple layer paper container which does not generate a problem of odor, has a favorable heat-sealability, and at the same time, has a favorable sliding property, and therefor, has a superior mechanical compatibility at the time of forming or handling. CONSTITUTION:A multiple layer paper container 1 consists of a layer 11 which forms the inner surface of the container wall, is made of a polyethylene film of which the surface is uneven, and a layer 14 which forms the outer surface is made of a polyethylene layer which is extrusion-laminated. Since the polyethylene film which is previously formed at a low temperature is used as the layer to form the inner surface, odor is not given to a content. Also, mat finish with an uneven condition is applied to this film, and therefore, the inner surface has sliding property. In addition, since the layer to form the outer surface is made of polyethylene, the heat-sealability is also favorable.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-layered paper container, and more specifically, it has a good slipperiness on the inner surface, has good mechanical suitability during molding and handling, and reduces odor. And a multi-layer paper container excellent in heat sealability.

[0002]

2. Description of the Related Art Paper cups are widely used in various places including vending machines for beverages such as juice and coffee. Regular paper cups are not made of a single sheet of paper, but are multi-layered papers that have a resin layer, etc., in consideration of machine suitability during paper cup molding, content resistance, ease of handling, and other conditions. It is made of composite material.

Not only paper cups but also many types of aseptic filled food and drink products such as milk, alcohol and juice (preservation)
As the container, a multilayer container using paper is used. Such a container has a multi-layer structure in which a resin layer, an aluminum foil and the like are laminated on a container base paper.

Such a multilayer paper container generally has a polyethylene layer formed by extrusion lamination on both inner and outer surfaces, and the surface of the polyethylene layer is matted by using a chill roll containing a mesh. This matting gives slipperiness to the surface of the container / paper composite,
Mechanical suitability at the time of container molding and filling of contents (slipperiness with mandrel and guide of container forming machine is good, smooth folding and bending, and smooth operation of contents filling machine That can be dealt with).

[0005]

In such a conventional multi-layer paper container, the polyethylene layer formed by extrusion lamination is arranged as the inner surface layer of the container as described above, but the extrusion temperature of polyethylene is 280 to 300 ° C. Due to the extent, polyethylene is highly oxidized. As a result, the polyethylene layer had an odor (oxidation odor), which was transferred to the contents and was often a problem.

Further, the polyethylene layer formed by matte extrusion lamination is somewhat inferior in heat sealability, and there are problems in sealing the container and attaching the lid member.

Therefore, the object of the present invention is to provide a multi-layered paper container which is free from the problem of odor, has a good heat-sealing property, has a good surface slipperiness, and is excellent in mechanical suitability during molding and handling. Is to provide.

[0008]

As a result of earnest research in view of the above object, the present inventor has made the surface of a polyethylene film, which has been formed in advance, an uneven surface as a polyethylene layer to be an inner surface of a container. By forming a mat and adhering this to a composite material for a container to form a container, there is no problem of odor, there is slipperiness on the inner surface, and a container with good heat sealability can be obtained. Discovered,
The present invention has been completed.

That is, the multi-layered paper container of the present invention is characterized in that the layer forming the inner surface is made of a polyethylene film having an uneven surface and the layer forming the outer surface is made of an extrusion-laminated polyethylene layer.

[0010]

[Function] As the innermost layer of the container, 150 ℃ ~ 200
Since the polyethylene film formed at a relatively low temperature of ℃ is provided by adhesion, the oxidative odor that the polyethylene layer obtained by extrusion lamination has is reduced, and the odor is less likely to attach to the contents.

Further, since the surface of the film is provided with irregularities in advance, the slipperiness of the inner surface of the obtained composite material is good, and the mechanical suitability during molding or handling is improved. That is, at the time of molding, the paper composite material is bent by a guide of a processing machine or wound around a mandrel to have a container shape, but if slipperiness is poor, these operations are not successful. Regarding the handling of the container, the following can be said. That is, the paper containers are usually piled up and removed one by one by a machine to fill the contents, but it is difficult to remove one by one if the surface is not slippery. Therefore, if the slipperiness of the inner surface is improved, the inner surface and the outer surface of the upper and lower containers, which are in close contact with each other at the time of stacking, are easily separated.

Furthermore, since a polyethylene film formed at a relatively low temperature is used for the inner surface, the heat sealing property is also improved. Further, by providing an aluminum layer and further a polyester resin layer inside the polyethylene film layer, the contents resistance (gas passage resistance, leak resistance, etc.) can be improved.

[0013]

The present invention will be described in detail below with reference to the accompanying drawings. FIG. 1 is a partial sectional view showing a layer structure of a multi-layered paper container according to an embodiment of the present invention. The multilayer paper container 1 has a layer 11 made of a polyethylene film, an aluminum layer 12, a container base paper 13 and a polyethylene layer 14 in order from the innermost layer to the outside.

The layer 11 made of a polyethylene film is formed in advance by, for example, the T-die method or the inflation method, and is made of a film whose surface is formed into an uneven mat by various methods described later. .. For this polyethylene film layer, it is particularly preferable to use low-density polyethylene or linear low-density polyethylene.

In the film formation by the T-die method or the inflation method, polyethylene is formed at a low temperature of about 150 ° C. to 200 ° C., so that the oxidative odor is reduced. Therefore, the polyethylene film layer 11 as the innermost layer does not give an odor to the contents. This polyethylene film layer 11
The thickness of 30 to 100 μm is recommended.

The matting of the polyethylene film can be carried out by various methods. For example, a film obtained by the T-die method may be mechanically heated by a mechanical method such as embossing using a chill roll containing a mesh, or a chill roll or a pinch roll of an inflation method may be heated and mechanically There are a method of embossing and a method of polishing with a brush or the like. Further, in the film formation, a film having a concavo-convex surface can be formed by using a material in which a resin having low compatibility is mixed in advance with a main component such as polyethylene. In case of embossing with mesh, 60
It is good to have a concavo-convex state of about 80 mesh.

A general-purpose soft aluminum foil can be used for the aluminum layer 12. Aluminum foil having a thickness of about 6 to 15 μm can be used. The aluminum layer 12 improves gas barrier properties, light shielding properties, and the like. It is also possible to use a layer of vapor-deposited aluminum instead of the aluminum foil.

The thickness of the container base paper 13 can be variously changed depending on the use of the container, but is generally about 100 to 500 μm.

The polyethylene layer 14 which is the outermost layer of the container is
In this embodiment, the polyethylene layer is formed by ordinary extrusion lamination. This layer is for the purpose of protecting the base paper of the container and heat-sealing it by superposing it on the polyethylene layer on the inner surface, and a thickness of about 20 to 60 μm is sufficient.

The paper composite material having such a structure can be manufactured, for example, by the following method.

First, a film is formed by an inflation method or a T-die method, and then a polyethylene film 11 having a surface mattized by the above-mentioned method and an aluminum foil 12 are bonded by a dry lamination method or the like.
In the dry lamination method, a resin such as acrylic, epoxy, urethane, or polyester that acts as an adhesive is dissolved in an organic solvent and applied onto the aluminum foil 12, and after (semi) drying with hot air or heating, the polyethylene film 11 is put together. Apply heat and pressure.

Next, the laminated body of the aluminum foil 12 and the polyethylene film 11 obtained as described above and the container base paper 13 are bonded together on the surface of the aluminum foil 12. This adhesion can be performed by a so-called wet lamination method, in which an adhesive agent of an aqueous solution is applied to the container base paper 13 and bonded together, but a resin such as polyethylene or Surlyn can also be used as an adhesive agent.

Further, a polyethylene layer is formed on the surface of the container base paper 13 of the laminate obtained by the above method by the extrusion lamination method to obtain a paper composite material having the constitution shown in FIG.

The multi-layered paper container made of the composite material having such a structure can be used as a container for juice, coffee, liquor or the like.

FIG. 2 is a partial sectional view showing the layer structure of a multi-layered paper container according to another embodiment of the present invention. The multi-layer paper container 2 comprises, in order from the inside, a polyethylene film layer 21 having irregularities on its surface, a container base paper 22, and a polyethylene layer 23 formed by extrusion lamination. The polyethylene film layer 21, the container base paper 22, and the polyethylene layer 23 by extrusion lamination are the same as those used in the multilayer paper container 1 shown in FIG. 1, and have a structure lacking the aluminum foil layer. The paper composite material 2 having such a structure can be used, for example, in a paper cup for an automatic vending machine such as juice or coffee, or a pack of milk or the like.

FIG. 3 is a partial sectional view showing the layer structure of a multi-layered paper container according to still another embodiment of the present invention. The multi-layered paper container 3 is composed of a polyethylene film layer 31 having an uneven surface, a polyester resin layer 32, an aluminum layer 33, a container base paper 34, and a polyethylene layer 35 formed by extrusion lamination in order from the inside. Here, as the polyester resin layer 32, polyethylene terephthalate is preferably used, but it is particularly preferable to use uniaxially or biaxially stretched one. The layers other than the polyester resin layer 32 may be the same as those of the multilayer paper container 1 shown in FIG.

The polyester resin layer 32 such as polyethylene terephthalate serves to cover the aluminum foil 33, even if the aluminum foil 33 has pinholes. Further, during heat sealing, even if a part of the polyethylene layer of the seal part escapes (becomes thin or part is cut) by the pressure, this polyester resin layer prevents the pinhole. Therefore, when the sealability is particularly improved, it is preferable to have a structure like the paper composite material 3. Here, the thickness of the polyester resin layer 32 is 12 to 25.
It is good to set it to about μm.

It is also possible to use a multilayer paper container in which nylon or polypropylene resin is placed in place of the polyester resin at the position of the polyester resin layer 32 in the multilayer paper container 3.

In the production of the paper composite material having the structure shown in FIG. 3, first, a polyethylene film layer 31, a polyester resin layer 32 and an aluminum foil 33 are formed into a laminated body by a dry lamination method, and subsequently, this is used to produce the laminated body shown in FIG. The container base paper 34 and the polyethylene layer 35 are manufactured in the same manner as the multilayer paper container shown in the figure.
Are stacked.

Container 3 made of a paper composite material having such a structure
For example, juice or coffee that is stored at room temperature for a long time,
Suitable for sake and other aseptic filling containers.

Further, the present invention is not limited to the above-mentioned three modes, and may be a multi-layer paper container having a layer structure in which a resin layer is further added. For example, as shown in FIG. 4, in order from the innermost layer to the outer side, a polyethylene film layer 41, a polyethylene layer 42 by extrusion lamination, a polyethylene terephthalate layer 43, an aluminum layer 44, a container base paper 45, and an outermost layer. The multi-layered paper container 4 may be composed of the polyethylene layer 46 of FIG. Here, the polyethylene layer 42 formed by extrusion lamination serves as an adhesive layer between the polyethylene film layer 41 and the polyethylene terephthalate layer 43. Since the polyethylene layer 42 is covered with the polyethylene film layer 41, the contents of the container do not come into contact with the polyethylene layer 42 and the odor does not transfer to the contents.

As a method for producing the paper composite material having the structure shown in FIG. 4, first, the polyethylene terephthalate layer 43 and the aluminum foil layer 44 are bonded by the dry lamination method, and further, the container base paper 45 is bonded by the wet lamination method to obtain the There is a method in which polyethylene layers 46 and 42 are formed by extrusion lamination on both surfaces of the laminated body, and then the polyethylene film layer 41 is dry-laminated or extrusion-laminated on the polyethylene layer 42.

In the multi-layer paper container 4, the polyethylene terephthalate layer 43 may be omitted and the multi-layer paper container 4 may be formed.

The present invention has been described above with reference to the drawings.
The present invention is not limited thereto, and various modifications can be made without departing from the idea of the present invention. For example, the polyethylene film used as the inner surface layer of the container is not limited to polyethylene, and a film of a copolymer of ethylene and another α-olefin, a polypropylene film, or the like can be used. Also, in the layer structure of the multi-layer paper container, the arrangement of each layer can be appropriately changed, and the outermost polyethylene layer can be a matte polyethylene film layer.

The present invention will be described in more detail with reference to the following specific examples. Example 1 and Comparative Example 1 A linear low-density polyethylene film having a thickness of 40 μm was produced by the inflation method. The resin temperature during film formation is
It was 150 ° C.

This polyethylene film was matted by embossing with a roll containing a mesh. The mesh roughness used was # 60.

Next, the matted polyethylene film obtained above, the soft aluminum foil having a thickness of 9 μm, and the polyethylene terephthalate film having a thickness of 12 μm were matted polyethylene film / polyethylene using a urethane adhesive. It was dry laminated so as to have a laminated structure of a terephthalate film / aluminum foil.

On the aluminum foil side of the laminate obtained above, a container base paper having a basis weight of 280 g / m ² was wet laminated. The adhesive used was a vinyl acetate adhesive.

After aging and sufficient drying, a polyethylene layer having a thickness of 20 μm was formed on the surface of the base paper for container by extrusion lamination using polyethylene. At this time, the polyethylene layer formed by extrusion lamination was matted by a chill roll containing a mesh.

A 1 liter juice paper container was manufactured using the obtained multi-layered paper composite material. In the processing of the paper composite material into the container, the slipperiness of the paper composite material with the guide of the processing machine was good, and the paper composite material could be easily folded into a container without causing a catch or the like.

For comparison, a container of polyethylene extruded as the innermost layer was produced instead of matted polyethylene.

Regarding the containers of Example 1 and Comparative Example 1, 6
After filling with water at 5 ° C. and cooling naturally, an odor sensitivity test was conducted. As a result, the water in the container of Example 1 was
It was found that the odor was significantly less than that of water in the container. Both containers had good sealing properties.

Example 2 The matted polyethylene film used in Example 1 and a container base paper having a basis weight of 220 g / m ² were wet laminated with a vinyl acetate adhesive.

Next, a polyethylene layer having a thickness of 20 μm was formed on the raw paper side of the container by extrusion lamination. The polyethylene layer formed by this extrusion lamination was prepared as in Example 1.
Matted as in.

A paper cup was produced using the obtained paper composite material. In the manufacturing process, the paper composite material could be easily processed into a paper cup without winding around the mandrel of the processing machine.

This container was filled with water at 65 ° C., naturally cooled, and then subjected to an odor sensitivity test. As a result, it was found that the water in this container had significantly less odor than the water in the container of Comparative Example 1 described above.

Further, the sealing property of the container was also good. Further, when a plurality of the obtained paper cups were overlapped once and the paper cups were taken out one by one from the stack, it was easy to pull out the paper cups.

[0048]

As described in detail above, the multi-layered paper container of the present invention does not transfer the polyethylene oxidative odor to the contents, and because of the good slidability of the inner surface, it can be machined during molding and handling. Good suitability and good handling. Also, the heat sealability is improved.

Therefore, the multi-layered paper container of the present invention is a container for various food and drink products such as vending machine paper cups for beverages such as juice and coffee, particularly containers for juice, milk, liquor and other aseptic filling products. Can be used as

[Brief description of drawings]

FIG. 1 is a partial sectional view showing a layer structure of a multi-layered paper container according to an embodiment of the present invention.

FIG. 2 is a partial cross-sectional view showing a layer structure of a multi-layer paper container according to another embodiment of the present invention.

FIG. 3 is a partial sectional view showing a layer structure of a multi-layer paper container according to still another embodiment of the present invention.

FIG. 4 is a partial sectional view showing a layer structure of a multi-layered paper container according to another embodiment of the present invention.

[Explanation of symbols]

1, 2, 3, 4 Multi-layer paper container 11, 21, 31, 41 Matted polyethylene film 12, 33, 4 Aluminum layer 13, 22, 34, 45 Container base paper 14, 23, 35, 42, 46 Polyethylene by extrusion lamination Layer 32, 43 Polyethylene terephthalate layer

Claims (3)

[Claims] 1. A multi-layered paper container, wherein the layer forming the inner surface is made of a polyethylene film having an uneven surface, and the layer forming the outer surface is made of a polyethylene layer extruded and laminated. 2. The multi-layered paper container according to claim 1, wherein
A multi-layered paper container having an aluminum layer between a layer composed of a container base paper and a polyethylene film layer forming an inner surface. 3. The multi-layered paper container according to claim 2,
A multilayer paper container, further comprising a polyester resin layer disposed between the aluminum layer and the polyethylene film forming the inner surface.