JPH03108541A - Lamianted material for vessel - Google Patents

Abstract

PURPOSE:To obtain a laminated material for a vessel, a polyester layer of which is not cracked, from which a liquid is not leaked with time and in which no peeling is generated, by forming a heat-sealing polyester layer onto a biaxially oriented polyester film through a layer composed of a specific compound. CONSTITUTION:A laminated material is mainly composed of a paper base body 1, a metallic foil 3 shaped through an ionomer layer 2, a biaxially oriented polyester film 4 formed onto the metallic foil 3, and a polyester layer 6 shaped onto the biaxially oriented polyester film 4 through a layer 5 consisting of a mixture containing the copolymer of ethylene and unsaturated carboxylic acid or ester thereof and not less than 1wt.% polyester. Accordingly, a vessel for a drink, the polyester layer of which is not cracked on the formation of a ruled line, bending in a canning process, etc., from which a liquid is not leaked with time and in which no peeling is generated, is acquired.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application 1] The present invention relates to a laminated material for containers, more specifically, metal a1
This invention relates to a laminated material suitable as a constituent material of a paper-based beverage container.

[Prior Art] Beverages such as alcoholic beverages and whiskey have a high permeability into the material that makes up the container, so conventionally, the material that makes up the container for such beverages is to coat paper with a metal foil such as aluminum through an ionomer layer, etc. was used. However, when such metal foil is used, there is a problem that the metal foil cracks, especially at the folded parts of the container, and to prevent this, a biaxially stretched polyester film is usually placed on top of the metal foil. . Furthermore, in the case of such beverage containers, the top of the biaxially stretched polyester film, that is, the portion that constitutes the inner surface of the container, is conventionally made of polyolefin because of its hygienic properties, water resistance, moisture resistance, and heat sealability. Those processed by etc. were used.

However, when using the above-mentioned constituent materials, there is a problem that the original aroma, taste, etc. of the drink cannot be maintained because polyolefin has the property of adsorbing or permeating the flavor components of the drink. When produced by extrusion coating of polyolefin, oxidation is likely to occur, which also causes the problem of generating an unpleasant odor.

In order to solve the above problems, in recent years polyester has been used instead of polyolefin as a constituent material for the containers.

[Problems to be Solved by the Invention] However, in the above-mentioned constituent materials using polyester instead of polyolefin, the layer made of the polyester has a drawback that it lacks flexibility. There were problems such as cracks occurring in the polyester layer during bending during the can manufacturing process, and over time, the beverage content permeated, causing leakage and peeling.

Therefore, the object of the present invention is to provide a laminated material for containers having a polyester layer on a biaxially stretched polyester film, and in particular, to provide a laminated material for containers having at least a metal foil such as aluminum, a biaxially stretched polyester film, and a polyester layer on a paper base in this order. When creating borders for laminated materials for containers,
The object of the present invention is to provide a laminated material for container 3, which does not cause cracking of the polyester layer during bending in the can manufacturing process, and does not cause liquid leakage or peeling over time.

[Means for Solving the Problems] The present inventors have made extensive studies in view of the above-mentioned problems, and have found that the above-mentioned object of the present invention is to apply ethylene and an unsaturated carboxylic acid or an ester thereof onto a two-wheel stretched polyester film. A laminated material for containers, in which a heat-sealable polyester layer is formed through a layer consisting of a mixture containing a copolymer of in this order, and has a heat-sealable polyester layer on the polyester film via a layer consisting of a copolymer of ethylene and an unsaturated carboxylic acid or its ester and a mixture containing 1% by weight or more of polyester. It has been found that this can be achieved by providing a laminated material for containers.

The present invention will be explained in more detail below.

FIG. 1 is a schematic cross-sectional view showing one example of the V1 layer material of the present invention. According to FIG. 1, the laminated material of the present invention includes a paper substrate 1 and a metal foil 3 provided via an ionomer layer 2, for example.
and a biaxially stretched polyester film 4 provided on the metal foil 3, and a layer 5 made of a mixture containing a copolymer of ethylene and an unsaturated carboxylic acid or its ester, and 1% by weight or more of polyester. It is mainly composed of a polyester layer 6 provided on a biaxially stretched polyester film 4. For example, a polyethylene layer 7 is provided on the paper substrate 1 on the side opposite to the polyester layer 6, if necessary, and desired printing can be performed on the polyethylene layer 7.

The biaxially oriented polyester film constituting the laminated material of the present invention prevents the contents from permeating due to cracks in the gold 1iLi5, and the polyester resin forming the polyester film is a polysalt 1. ! Consists of a copolymer of acid and polyhydric alcohol. As such a polybasic acid, one containing terephthalic acid as a main component is preferable, and as a polyhydric alcohol, one containing ethylene glycol as a main component is preferable. The above polybasic acids and polyhydric alcohols can each contain other polybasic acids and other polyhydric alcohols as comonomer components.

Other polybasic acids that can be included as comonomer components in the polybasic acid include aromatic dicarboxylic acids such as isophthalic acid, naphthalene dicarboxylic acid, diphenyl dicarboxylic diphenoxyethane dicarboxylic acid, diphenyl ether dicarboxylic acid, and diphenyl sulfone dicarboxylic acid; hexahydro Alicyclic dicarboxylic acids such as terephthalic acid and hexahydroterephthalic acid; aliphatic dicarboxylic acids such as adivic acid, cepatic acid and agylaic acid; p-β-hydroxybenzoic acid, p-oxybenzoic acid, εAL Oxyacids such as cicabronic acid; trimellitic acid, trimesic acid, 3.3'
, 5.5'-tetracarboxydiphenyl, and other aromatic polybasic acids; aliphatic polybasic acids such as butane atracarboxylic acid; and oxypolycarboxylic acids such as tartaric acid and malic acid.

In addition, other polyhydric alcohols that can be included as comonomer components in polyhydric alcohols include trimethylene glycol, tetramethylene glycol, hexamethylene glycol, decamethylene glycol, neopentylene gelicol, diethylene glycol, 1-cyclohexanedimethylol, 1,4-cyclohexanedimethylol, 2,2-bis(4-β-hydroxyethoxyphenyl)propane, bis-(4-β-hydroxyethoxyphenyl)sulfonecyclohexane, 1゜4-bis(
β-hydroxyethoxy)benzene, 1,3-bis(β
-Glycols such as hydroxyethylbenzene: Polyhydric alcohols such as phloroglycine, 1,2゜4.5-tetrahydroxybenpine, glycerin, trimethylolethane, trimethylolpropane, and pentaerythryl Can be mentioned.

In the present invention, the polyester resin may contain a nucleating agent or various additives such as a lubricant, an antiblocking agent, a stabilizer, an antifogging agent, a coloring agent, and the like. As such a nucleating agent, fine particles of polyolefins or inorganic substances having a particle size of 2 to 10 μm are used. Examples of polyolefins include low density polyethylene, high density polyethylene, linear low density polyethylene, polypropylene, etc. Examples of inorganic substances include carbon black, talc,
Examples include gypsum, silica, alumina, calcium carbonate, titanium dioxide, graphite, powdered glass, powdered metal, and the like.

The two-wheel stretched polyester in J3 of the present invention is preferably one obtained by biaxially stretching the above polyester resin by 4 to 6 times in the longitudinal direction and 4 to 6 times in the transverse direction after molding, and preferably heat-setting after biaxial stretching. used.

Further, the thickness of the biaxially stretched polyester film obtained as described above is preferably 9 to 25 μm.

In the laminated material of the present invention, the polyester forming the heat-sealable polyester layer provided on the biaxially stretched polyester film is a copolymer of a poly-base acid and a polyhydric alcohol. Such a polybasic acid preferably contains 10 to 50% of the total acid components of isophthalic acid and terephthalic acid as the main components, and the polyhydric alcohol preferably contains ethylene glycol as the main component. . The polybasic acid and polyhydric alcohol may each contain, as a comonomer component, another polybasic acid and another polyhydric alcohol similar to the polyester resin forming the biaxially oriented polyester film.

Further, the polyester resin may contain various additives such as a nucleating agent, a lubricant, an undeblocking agent, a stabilizer, an antifogging agent, and a coloring agent, like the polyester of the biaxially stretched polyester film, but preferably is preferably not included from the viewpoint of preventing adsorption of the five components of the contents such as beverages.

The polyester used in the heat-sealable polyester layer is preferably unstretched or slightly stretched by about 1.1 times from the viewpoint of preventing shrinkage during heat sealing.

Further, the thickness of the heat-sealable polyester layer is arbitrary, but is used, for example, in the range of 1 to 100 μm.

In the present invention, between the two-wheel stretched polyester film and the heat-sealable polyester layer, a mixture containing a copolymer of ethylene and an unsaturated carboxylic acid or its Nisdel and a polyester of 1% or more is provided as an adhesive layer. .

The above copolymer has an unsaturated carboxylic acid content m of 3 to
It is preferably 12% by weight, and in the case of ester, it is preferred that the ester component is 1 to 10 ffia%. Such unsaturated carboxylic acids or esters thereof include:
For example, acrylic acid, methacrylic acid, methyl acrylate,
Examples include methyl methacrylate, ethyl acrylate, and ethyl methacrylate.

The polyester contained in the mixture according to the present invention is a copolymer of a polybasic acid and a polyhydric alcohol, and is contained to improve adhesion to the polyester layer.

The polybasic acid preferably contains terephthalic acid as a main component, and the polyhydric alcohol preferably contains co[ethylene glycol] as a main component.

The above-mentioned polybasic acid and polyhydric alcohol can each contain, as comonomer components, other polybasic acids and other polyhydric alcohols similar to those mentioned above with respect to the polyester constituting the biaxially oriented polyester film.

The mixture according to the present invention contains the above-mentioned polyester component in an amount of 1% or more in terms of adhesive strength, but preferably 1 to 1%.
Contains 10fim%.

Further, the layer made of the above mixture usually has a thickness of 1 to 100 μm. That is, a thickness of less than 1 μm is difficult to implement, and a thickness of more than 100 μm is not useful for the present invention.

The laminated material of the present invention mainly has a polyester layer on a two-wheel stretched polyester film as described above, with a mixture containing a copolymer of ethylene and an unsaturated carboxylic acid or its ester and a polyester. When the V4 layer material is used particularly for beverage containers etc., the metal foil and the biaxially oriented polyester film are provided in this order on the paper, and then the heat-sealable polyester film is placed on the polyester film via the mixture layer according to the present invention. It is advantageous to have a construction with layers.

The paper used for the above-mentioned laminated material is not particularly limited as long as it can be used as a structural support for containers;
Preferably, those having a ballast value of 100 to 400 g/l', particularly preferably 200 to 350 (]/f, can be used. Such materials are generally made of white paperboard, base paper for milk cartons, etc.

In addition, the metal foil provided on the paper has a height of 6 to 2
A material made of aluminum with a diameter of 0 μm is preferably used. Such metal foil is provided on the paper using, for example, polyethylene, ethylene-methacrylic acid copolymer, ionomer resin, or the like.

Further, a layer made of polyethylene or the like may be provided on the paper opposite to the metal foil.

The laminated material of the present invention may have various layer configurations within the scope of the present invention, such as printing ink/polyethylene/paper/ionomer/aluminum foil/biaxially oriented polyester film/mixture/polyester, etc. can be mentioned.

The laminated material of the present invention is manufactured, for example, by the following method.

That is, (1) extrusion coating polyethylene on paper and printing on the polyethylene. On the other hand, (2) after dry laminating a two-wheel stretched polyester film on an aluminum foil, extrusion coating the mixture according to the present invention on the polyester film, and then extrusion coating the polyester on the layer made of the mixture.

(3) The paper surface of (1) and the aluminum foil surface of (2) are adhered via polyethylene, ionomer resin, ethylene-methacrylic acid copolymer, etc. Alternatively, the above step (2) can be carried out by co-extruding the mixture according to the present invention and polyester, and then extruding this onto a dry-laminated aluminum foil and a biaxially stretched polyester film on the polyester film side. Laminate it and do it.
The steps (1) and (3) can also be created in the same manner as above.

Furthermore, when carrying out the above extrusion coating, each layer of paper, polyethylene, and mixture may be subjected to surface treatment such as corona discharge treatment, if necessary.

Containers to which the laminated material of the present invention is preferably applied include:
There are various types of containers containing liquid beverages with high permeability, such as alcohol, whiskey, juice, coffee, barley tea, oolong tea, soups, etc.
Examples include tetra pack-type containers, block-type containers, and the like, the external appearance of which is shown in FIG. 3 and FIG. In order to create, for example, the container shown in FIG. 2 above using the laminated material of the present invention, first
As a step, a step of forming a sleeve as shown in FIG. 4 is performed. In this process, one side edge is folded back to form a sleeve so that the end surface of the container constituent material is not exposed to the inner surface of the container and comes into contact with the beverage content. The side edges of the polyester are processed and sealed,
Next, the bottom can be formed as a second step, the contents can be filled as a third step, and finally the top can be formed as a fourth step to create the container.

Another method is to form a container by heat-sealing the polyester surfaces together when filling the roll-shaped laminated material of the present invention with contents.

[Example] The present invention will be explained in more detail with reference to Examples below.

A polyester containing terephthalic acid as a main component as a polybasic acid and ethylene glycol as a main component as a polyhydric alcohol is stretched 6 times in length and width and heat-set to a thickness of 1.
A 2μ biaxially stretched polyester film and a 9μ thick aluminum foil are dry laminated using a two-component urethane adhesive, and 1.0ffiit% polyester (terephthalate) is added to the polyester film side of the resulting laminated film. Acid 40 mol%, Isophthalic acid 10 mol%
, consisting of 50 mol% of ethylene glycol) and acid component 9
A mixture consisting of % by weight of ethylenically unsaturated carvone MEMΔA (ethylene-methacrylic acid) was extrusion coated to a thickness of 40μ.

Further, the layer made of the mixture was subjected to a corona discharge treatment, and then extrusion coated with the above polyester to a thickness of 20 μm. Next, the aluminum foil surface of the laminate film was adhered with an ionomer resin to the surface opposite to the polyethylene layer of a white paperboard coated with 15 to 20 μm of polyethylene and having a scale of ω 30 h/f, to create a laminate material 1 of the present invention. .

In addition, laminated materials n2 to n4 were created in the same manner as above, except that the polyester content in the mixture or the paper scale ω was changed as shown in Table 1 in creating the laminated material 1. Furthermore, when creating the laminated material 1, no mixture layer was provided,
Laminated material IP45 and &i layer material 5 were prepared in the same manner except that the polyester layer was set to a thickness of 60μ and provided directly on the two-wheel stretched polyester film, except that the paper scale was changed as shown in Table 1. Laminated material 6
It was created.

Containers having the shape shown in FIG. 2 were created for each of the obtained laminated materials 1 to 6. At this time, leakage or crease formation at the folded portions was examined to determine the occurrence of cracks in the polyester layer. The results are shown in Table 1.

From Table 1, all containers obtained from the laminated materials 1 to 4 of the present invention in which a polyester layer was provided through a layer of the mixture according to the present invention had liquid leakage b from the folded portion, etc., and cracks in the polyester layer. This made it an excellent beverage container.

[Effects of the Invention] As explained in detail above, by using the laminated material of the present invention, cracks do not occur in the polyester layer during creasing, bending in the can manufacturing process, etc., and liquid leakage over time is prevented. , it is possible to provide a beverage container that does not cause peeling.

[Brief explanation of drawings]

FIG. 1 is a schematic sectional view showing an example of the laminated material of the present invention, and FIGS. 2 and 3 are perspective views showing an example of a container made using the laminated material 1 of the present invention. Yes, Figure 4 shows the 2nd
In the production of the container shown in Figures and Figure 3 (this is a perspective view showing the process of making a pull sleeve). <Main reference numbers> 1...Paper 2...Adhesive layer 3...Metal foil 4 ... Biaxially stretched polyester film 5 ... Mixture layer 6 ... Piece 1 - Sealing polyester layer 7 ... Polyethylene layer 8 ... Sleeve part 9 ... Bottom part
10...Top 11...Polyester layer (inside) 12...Polyethylene layer (outside)

Claims (2)

[Claims] (1) A heat-sealable polyester layer is formed on a biaxially stretched polyester film through a layer consisting of a copolymer of ethylene and an unsaturated carboxylic acid or its ester and a mixture containing 1% by weight or more of polyester. Laminated material for containers. (2) A paper substrate has a metal foil and a biaxially stretched polyester film in this order, and a copolymer of ethylene and an unsaturated carboxylic acid or its ester and 1% by weight or more of a polyester are provided on the polyester film. A laminated material for a container having a heat-sealable polyester layer via a layer made of a mixture containing.