JP4224900B2 - Laminate and sealed container - Google Patents

Description

【００１６】
【表２】

【００１７】
【発明の効果】
本発明による積層体は、深絞り成形性、酸素ガスバリアー性、内容物の保香性及び機械的強度等が優れており、食品、その他の包装用フィルム、特に紙に接着してラミネート品又はそれを賦形した容器用として好適である。[0001]
BACKGROUND OF THE INVENTION
The present invention is mainly used for food packaging films and containers, and can be deep-drawn, such as compressed air molding, and can be adhered to paper. The present invention relates to a multilayer film having excellent properties and mechanical strength, a multilayer container in which the film is bonded to paper, and a sealed container.
[0002]
[Prior art]
In the food industry, food is subject to quality degradation due to various changes such as loss of shape, color, taste, and aroma caused by microorganisms such as temperature, moisture, oxygen, light, etc. in the distribution process and bacteria and mold. As a method for preserving without deteriorating the quality until entering the person's mouth, conventionally, a method of directly adding additives such as preservatives and antioxidants to foods has been taken.
However, in recent years, in the food processing industry, regulations on additives to foods have become stricter, and the amount of additives used has been reduced or almost no longer used.
Under such circumstances, as a method for ensuring the long-term preservation of contents, a packaging material having excellent oxygen gas barrier properties is used.
In recent years, food contents have been upgraded, and consumers have been demanding flavors that are closer to freshness. In order to satisfy these requirements, the flavor retention of the contents is required.
As a plastic material conventionally used as a packaging material for these contents, there is a container formed with a relatively thick plastic sheet. On the other hand, as a flexible packaging material using a relatively thin plastic film, there has been a bag-like packaging material of a multilayer film called a retort pouch. Recently, a deep drawing molding machine for the purpose of speeding up and automating packaging. Etc., packaging materials that can be packaged at high speed are being demanded. Further, in the transportation stage in the food distribution process, there is a problem that bag breakage occurs depending on the transportation method, and a film having excellent mechanical strength is required.
In view of the above, the plastic film as a packaging material required in such a field has a plurality of properties such as deep drawability, oxygen gas barrier property, transparency, content aroma retention, and mechanical strength. What has a function and is inexpensive is required. In order to satisfy these requirements, it is conceivable that the film has a laminated structure of several layers, and various functions are dispersed in each layer so that the film has many functions comprehensively.
In order to obtain such a film, conventionally, a method of laminating individual films by a dry laminating method or the like has been used, but a single-layer film with limited thickness and performance must be selected. If the number of layers increases, the cost increases, and it is difficult to obtain a satisfactory product such as a solvent odor during molding.
In recent years, from the viewpoint of resource saving and environmental consideration, there has been a strong demand for low capacity and easy disposal of synthetic resin products, particularly packaging products that are used in large quantities. For this reason, various composite containers in which a synthetic resin film and a paper product such as paperboard are bonded have been proposed in the past, but none satisfying the above problems and the adhesive strength with paper have been obtained.
[0003]
[Problems to be solved by the invention]
The object of the present invention is that deep-drawing is possible, heat resistance, oxygen gas barrier properties, transparency, aroma retention of the contents and mechanical strength are excellent, and it can be laminated on paper as a support. The object is to provide a laminate.
[0004]
[Means for Solving the Problems]
The present invention includes an aroma retaining resin layer (A), a polypropylene layer (B), an adhesive resin layer (C), a gas barrier layer (D), and adhesive strength with paper (180 degree peeling, peeling speed 300 mm / min.). Is a laminate composed of an ethylene-based copolymer layer (E) having a width of 150 g / 15 mm or more. Preferred embodiments include (A)-(C)-(D)-(E), (A)-( C)-(B)-(C)-(D)-(E), (A)-(C)-(B)-(C)-(D)-(C)-(B)-(E) Or (A)-(C)-(B)-(C)-(D)-(C)-(B)-(C)-(E).
More preferably, the thickness of the ethylene copolymer layer (E) is 5 μm or more, the adhesive resin layer (C) is made of a modified polyolefin resin, and the gas barrier layer (D) is an ethylene-vinyl alcohol copolymer or One resin selected from polyester resin, polycarbonate resin, ethylene-vinyl alcohol copolymer, cyclic polyolefin resin, polyacrylonitrile resin, or these resins, made of nylon MXD6 It is the said laminated body which consists of a mixture of these.
Further, the present invention is a multilayer container in which the above laminate is bonded to paper on the (E) layer surface, and further has at least a heat-sealing property to the multilayer container with the aroma retaining resin layer (A). It is a sealed container in which a plastic laminated lid having a thermoplastic resin as a sealing layer is heat-sealed.
[0005]
DETAILED DESCRIPTION OF THE INVENTION
As resin used for the aroma retaining resin layer (A) of the present invention, polyester resin, polycarbonate resin, ethylene-vinyl alcohol copolymer, cyclic polyolefin resin, one resin selected from polyacrylonitrile resin, or these What consists of a mixture of these resin is preferable.
[0006]
The resin used for the polypropylene layer (B) used in the present invention is not particularly limited. However, in consideration of moldability during thermoforming, the melt index (JIS K6758) is 0.5 to 10.0 (g / 10 min). ), And more preferably 0.5 to 7.0 (g / 10 min). Further, for the purpose of reducing the amount of sheet / film sag during thermoforming, 0.930 g / cm ³ or less of polyethylene and its copolymer can be blended within a range not impairing heat resistance.
[0007]
Although it does not specifically limit as adhesive resin used for the adhesive resin layer (C) of this invention, Modified polyolefin resin, such as maleic anhydride modified polypropylene, is preferable. Also, different adhesive resins may be selected for the adhesive layers (A) and (B) and the adhesive layers (B) and (D).
[0008]
As the resin used for the gas barrier layer (D) of the present invention, an ethylene-vinyl alcohol copolymer or nylon MXD6 is preferable, and can be properly used depending on the purpose.
[0009]
The ethylene-based copolymer layer (E) of the present invention is used because it has a low melting point and excellent low-temperature heat sealability, and examples thereof include ethylene-vinyl acetate copolymer, low-density polyethylene, and ionomer. A terpolymer of ethylene-acrylic acid ester and maleic anhydride with good odor is preferred. The adhesive strength between the resin and the paper body (180 ° peeling, peeling speed 300 mm / min) needs to be 150 g / 15 mm width or more. It is also possible to mix thermoplastic resins such as polyethylene and polypropylene as long as the adhesive strength is not impaired. If the adhesive strength is less than this, when the lid material is sealed and opened in a container shaped with this laminate, the adhesive layer between the (E) layer and the paper body is destroyed and functions as a container. There is a risk of not being satisfied.
Further, it is preferable that the ethylene-based copolymer resin layer (D) is 5 μm or more in order to obtain 150 g / 15 mm width (180 ° peeling, 300 mm / min peeling speed) required for the adhesive strength with paper. . If it is less than 5 μm, sufficient adhesive strength cannot be obtained.
[0010]
As a laminated lid having a thermoplastic resin having heat-fusibility with the scent-retaining resin of the present invention as a sealing layer, as a sealing layer, homo, block, random, etc. polypropylene, a mixture of polypropylene and polyethylene, ethylene Examples thereof include a vinyl acetate copolymer, a carboxylic anhydride-modified polypropylene, and a mixture. These can be arbitrarily used as long as heat sealing with a container is possible.
As a layer other than the sealing layer of the lid member, an ethylene vinyl alcohol copolymer, vinylidene chloride copolymer, polyester or nylon deposited with inorganic silica or aluminum foil can be used as a gas barrier layer. Further, any thermoplastic resin film such as polyester, nylon, stretched polypropylene, cellophane, etc. can be used as the base material layer. However, since these base films may directly come into contact with a metal hot platen, it is necessary to take into consideration releasability from the metal during heating. These seal layers, gas barrier layers, and base material layers can be laminated by a dry lamination method, a co-extrusion method, an extrusion lamination method, or the like. Even if the number of lamination layers is three or more, there is no problem.
[0011]
The laminate of the present invention can be obtained by coextrusion, laminating or the like using the above resin. As the laminating process, any method such as co-extrusion laminating, dry laminating, and thermal laminating can be used.
The multilayer container of the present invention can be obtained by mounting a paper substrate in a mold and then vacuum forming or pressure forming the laminate of the present invention.
Although it does not specifically limit as a paper base material used for this invention, Paperboard board paper, white board paper, a yellow ball, a chip ball, a cup base paper etc. can be mentioned.
The sealed container of the present invention can be obtained by placing a multilayer container and a plastic laminated lid in a receiving mold and pressing the flange portion with a heated hot platen.
[0012]
【Example】
Hereinafter, the present invention will be described by way of examples, but this is merely an example, and the present invention is not limited thereto.
Table 1 shows the measured values of the layer structure, the oxygen gas barrier, and the adhesive strength between the laminate and the paper product in the laminates of Examples and Comparative Examples. The measuring method is as follows.
(1) Oxygen gas barrier property: According to OXTRAN method.
(2) Adhesive strength between the laminated body and the paper body; the laminated body is heated at 160 to 180 ° C. for 2 to 3 seconds, and molded and adhered inside the paper blanks (cup base paper) installed in the mold, A sample piece having a width of 15 mm was prepared, and the laminate and the paper blank were peeled 180 ° at a tensile strength of 300 mm / min, and the maximum load was recorded.
The resins used in the examples are as follows.
(A): specific gravity = 1.27, glass transition point = 81 ° C. amorphous polyethylene terephthalate (B): melting point = 160 ° C., melt index = 2.0 polypropylene (C): maleic anhydride modified polypropylene (D ): Ethylene vinyl alcohol copolymer having an ethylene ratio of 36 mol% (E): terpolymer of ethylene, acrylic acid ester and maleic anhydride having a melting point = 98 ° C. and a melt index = 8.0
Next, the laminates of Example 1 and Comparative Example 1 are shaped into 12 cm × 16 cm × 3.5 cm rectangular paper blanks (cup base paper) so that the paper layer is on the outside of the container to produce a multilayer container. A sealed container in which a thermoplastic laminated lid in which polypropylene (50 μm), ethylene vinyl copolymer (15 μm), nylon (15 μm), polyethylene terephthalate (12 μm) are laminated by a dry lamination method is sealed from the sealing layer as a lid. Was made. The gas barrier value of this sealed container is shown in Table 1.
[0014]
Next, the laminates of Examples 1 to 3 and Comparative Examples 1 to 3 were shaped into 12 cm × 16 cm × 3.5 cm rectangular paper blanks (cup base paper) so that the paper layer was outside the container. Multi-layer containers were made and filled with orange juice or curry. A sealed container sealed with aluminum foil was produced as a lid.
Table 2 shows the results of the fragrance retention (flavor retention) and storage stability of the contents.
The evaluation method is as follows.
(1) Flavor retention << Evaluation of orange juice >>
The amount of limonene that is a component in orange juice after storage for 1 month was measured on the innermost layer.
○: Almost no adsorption.
Δ: Slightly adsorbed.
X: Large amount of adsorption.
<Evaluation of curry>
The taste test of the contents after storage for 1 month was performed.
○: No change in flavor is observed.
Δ: A slight change in flavor is observed.
X: Changes in flavor are recognized. (Plastic odor is felt)
(2) Preservability: Evaluation after storage for 1 month << Evaluation of orange juice >>
○: Little decrease in vitamin C content and good taste.
×… Vitamin C content decreased greatly and taste change was recognized. << Evaluation of curry >>
○: Little oxidation of oil, suitable for edible use.
Δ: Suitable for edible use, but oxidation of oil is observed.
X: Oxidation of the oil is large, and it has a strong odor and is not edible.
[0015]
[Table 1]

[0016]
[Table 2]

[0017]
【The invention's effect】
The laminate according to the present invention has excellent deep drawability, oxygen gas barrier properties, fragrance retention and mechanical strength of the contents, etc., and adheres to food and other packaging films, particularly paper, to laminate products or It is suitable for a container in which it is shaped.

Claims (7)

Aroma-retaining resin layer (A) and polypropylene layer (B), adhesive resin layer (C), gas barrier layer (D), adhesive strength with paper (180 degree peeling, peeling speed 300 mm / min.) Is 150 g / 15 mm a product layer body Ru width or more ethylenic copolymer (E) Tona,
With rectangular paper blanks
Bonded on the (E) layer surface,
A multilayer container formed by vacuum forming or pressure forming so that the paper layer is outside the container. Adhesive strength (180 degree peeling, peeling speed 300 mm / min.) Between the aroma retaining resin layer (A) and the polypropylene layer (B), adhesive resin layer (C), gas barrier layer (D) and paper is 150 g / min. The ethylene-based copolymer (E) having a width of 15 mm or more is converted into ( A)-(C)-(B)-(C)-(D)-(E), (A)-(C)-(B)- (C)-(D)-(C)-(B)-(E) or (A)-(C)-(B)-(C)-(D)-(C)-(B)- The multilayer container according to claim 1, which is laminated in the order of (C)-(E). The multilayer container according to claim 1 or 2, wherein the ethylene copolymer layer (E) has a thickness of 5 µm or more. The multilayer container according to any one of claims 1 to 3, wherein the adhesive layer resin (C) is made of a modified polyolefin resin. The multilayer container according to any one of claims 1 to 4, wherein the gas barrier layer (D) comprises an ethylene-vinyl alcohol copolymer. The multilayer container according to any one of claims 1 to 5, wherein the gas barrier layer (D) is made of nylon MXD6. The fragrant resin layer (A) is made of one resin selected from polyester resin, polycarbonate resin, ethylene-vinyl alcohol copolymer, cyclic polyolefin resin, and polyacrylonitrile resin, or a mixture thereof. The multilayer container of any one of -6.