Molded containers and packaging

Abstract

To inexpensively provide a container having good appearance, as a container obtained by molding a laminate having a metal foil layer and an outside resin film layer.SOLUTION: In a laminate for a molding container, an outside resin film layer 12 includes at least a first resin film layer 12B containing 50 mass% or more of a random copolymer containing propylene or a polymer of a propylene simple substrate, and a second resin film layer 12A which is composed of a resin composition containing a first elastomer-modified olefinic resin having a melting point of 155°C or higher and crystalline melting energy of 50 J / g or more, and a second elastomer-modified olefinic resin having a melting point of 135°C or higher and crystalline melting energy of 30 J / g or less. Each of the first and second elastomer-modified olefinic resins is composed of an elastomer-modified homopolypropylene resin and / or an elastomer-modified random copolymer that is an elastomer modified product of a random copolymer containing propylene as a copolymerization component.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a laminate used as a material for molded containers for sealingly packaging food and the like. of The present invention relates to a molded container and a package formed by filling the molded container with a content and then covering the container with a lid, and more particularly to a package having excellent long-term storage properties and good appearance. Growth This relates to containers and packages. [Background technology]

[0002] For example, as a container for packaging mizu yokan, jelly, baby food, nursing care food, etc. so as to enable long-term storage, a molded container is known which is formed into a cup-shaped laminate which includes a metal foil layer made of aluminum foil or the like, a sealant layer laminated on one of both sides of the metal foil layer which will become the inside of the container, and an outer resin film layer laminated on one of both sides of the metal foil layer which will become the outside of the container (see Patent Document 1 below, etc.). The outer resin film layer serves to prevent the surface of the container from being scratched or dented and to prevent the metal foil layer from being corroded, and also to impart formability to the laminate, and is composed of a single layer or multiple layers of films made of polyethylene terephthalate resin, nylon resin, polypropylene resin, etc. A lid having a heat-fusible resin layer as its innermost layer is then heat-sealed to the flange of the molded container filled with the contents such as food, thereby obtaining a package. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 6-345123 Summary of the Invention [Problem to be solved by the invention]

[0004] In the above-mentioned molded container, in order to enhance the design of its appearance, to impart appropriate flexibility to the resin composition to improve moldability, or to improve the impact resistance of the outer layer of the container in a frozen state, it is conceivable to use a film made of a polypropylene resin or the like blended with an elastomer as the outer resin film layer of the laminate for the molded container. However, when such a laminate is used to form a molded container, the surface of the resulting molded container may become whitened, which may impair the appearance of the container.

[0005] The present invention has been made in view of the above problems, and provides a laminate for a molded container, comprising a metal foil layer and an outer resin film layer. of To provide a molded container obtained by molding and a package obtained by sealingly packaging the contents using the molded container, which has excellent long-term storage properties and good appearance at low cost. [Means for solving the problem]

[0006] In order to achieve the above object, the present invention comprises the following aspects.

[0007] 1) A molded container formed by molding a laminate for a molded container into a cup shape and having a flange on an opening periphery, The laminate for forming a container is A metal foil layer and an outer resin film layer laminated on one of both sides of the metal foil layer that is to be the outer side of the container. Cage , The outer resin film layer is No. a multi-layer structure having at least two or more layers, the multi-layer structure having at least one resin film layer and a second resin film layer made of a resin composition including a first elastomer-modified olefin-based resin having a melting point of 155°C or higher and a crystalline melting energy of 50 J / g or higher, and a second elastomer-modified olefin-based resin having a melting point of 135°C or higher and a crystalline melting energy of 30 J / g or lower; the first resin film layer is interposed between the metal foil layer and the second resin film layer, The first elastomer-modified olefin-based resin and the second elastomer-modified olefin-based resin are each 、 Elastomer modified homopolypropylene resin and / or elastomer modified random copolymerIt consists of: The elastomer-modified random copolymer is an elastomer-modified random copolymer containing propylene as one of the copolymerization components, a total content of the first elastomer-modified olefin-based resin and the second elastomer-modified olefin-based resin in the second resin film layer being 50% by mass or more; 。

[0008] 2 ) the above-mentioned filled with contents 1 ) a lid is joined to a flange of the formed container so as to cover the opening of the formed container.

[0009] In this specification and claims, the "melting point" refers to the melting peak temperature (Tmp) measured by differential scanning calorimetry (DSC) in accordance with JIS K7121-1987. Similarly, "crystalline melting energy" refers to the heat of fusion (crystalline melting energy, ΔH) measured by differential scanning calorimetry (DSC) in accordance with JIS K7122-1987. When there are two or more crystalline melting peak curves and two or more crystalline melting energies (ΔH1, ΔH2), the highest crystalline melting energy value is indicated. Effect of the Invention

[0010] 1) Above of molded container To If so, Laminate for molded container The second resin film layer of the multiple outer resin film layers is made of a resin composition that combines a first elastomer-modified olefin resin having a melting point of 155°C or higher and a crystalline melting energy of 50 J / g or higher with a second elastomer-modified olefin resin having a melting point of 135°C or higher and a crystalline melting energy of 30 J / g or lower. Therefore, a molded container obtained by molding this laminate has good compatibility between the elastomer component and the olefin resin in the first and second elastomer-modified olefin resins of the resin composition, good dispersibility of the elastomer component, and high bonding strength at the interface between the olefin resin phase and the elastomer component. Therefore, the above 1) ofDuring molding of the laminate, stress is prevented from peeling off at the interface between the olefin resin phase and the elastomer component, which would result in the generation of spaces called voids. This also prevents deterioration of transparency due to the difference in refractive index between the resin and voids, i.e., whitening. Therefore, the above 1) of molded container To This makes it possible to obtain a molded container having an outer surface with a good appearance at low cost. Also, above 1) of molded container To According to this, since the melting point of the first elastomer-modified olefin-based resin in the resin composition constituting the second resin film layer is 155°C or higher, the outer resin film layer is less likely to be crushed, for example, when a lid is heat-sealed to the flange of a container formed by molding the laminate, and sufficient shape retention is ensured.

[0011] the above 2 The packaging body of the above-mentioned embodiment has good productivity and can reduce costs, and furthermore, the container has a good appearance with little whitening during molding, giving it a luxurious feel. [Brief description of the drawings]

[0012] [Figure 1] 1 is a partially enlarged cross-sectional view showing layer structures of two modes of a laminate for forming containers according to an embodiment of the present invention. [Diagram 2] 1A to 1C are vertical cross-sectional views showing a method for manufacturing a package according to an embodiment of the present invention in the order of steps. [Diagram 3] FIG. 2 is a perspective view of a package manufactured by the method. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] An embodiment of the present invention will be described below with reference to FIGS.

[0014] Fig. 1 shows the layer structure of a laminate for a molded container according to an embodiment of the present invention. The laminate (10) shown in the figure includes a metal foil layer (11) and an outer resin film layer (12) laminated on one of both sides of the metal foil layer (11) that will be the outer side of the container (2). The laminate (10) of this embodiment also includes an inner resin layer (13) laminated on one of both sides of the metal foil layer (11) that will be the inner side of the container (2).

[0015] More specifically, in the laminate (10) shown in FIG. 1(a), the outer resin film layer (12) has a two-layer structure consisting of a second resin film layer (12A) that forms the outer surface of the laminate (10) and a first resin film layer (12B) that is interposed between the second resin film layer (12A) and the metal foil layer (11). In addition, in the laminate (10) shown in FIG. 1(b), the outer resin film layer (12) has a three-layer structure consisting of a second resin film layer (12A), a first resin film layer (12B) interposed between the second resin film layer (12A) and the metal foil layer (11), and a third resin film layer (12C) laminated on the surface of the second resin film layer (12A) opposite the metal foil layer (11) to form the outer surface of the laminate (10).

[0016] The metal foil layer (11) serves to impart a barrier property to the laminate for forming containers (10) that prevents the intrusion of oxygen and moisture. As the metal foil constituting the metal foil layer (11), aluminum foil, iron foil, stainless steel foil, copper foil, etc. can be used, but aluminum foil is preferably used. In the case of aluminum foil, either pure aluminum foil or aluminum alloy foil may be used, and either soft or hard, but for example, annealed soft material (O material) of A8000 series (particularly A8079H or A8021H) classified by JIS H4160 with an iron content of 0.3 to 1.5 mass% is preferably used because it has excellent formability. One or both sides of the metal foil layer (11) may be subjected to a surface treatment such as a chemical conversion treatment, if necessary. Specifically, for example, the surface of the metal foil that has been degreased may be subjected to the following treatment: 1) Phosphoric acid, Chromic acid, and at least one compound selected from the group consisting of metal salts of fluorides and nonmetal salts of fluorides. 2) phosphoric acid; At least one resin selected from the group consisting of acrylic resins, chitosan derivative resins, and phenolic resins; and at least one compound selected from the group consisting of chromic acid and chromium (III) salts. 3) phosphoric acid; At least one resin selected from the group consisting of acrylic resins, chitosan derivative resins, and phenolic resins; At least one compound selected from the group consisting of chromic acid and chromium (III) salts; and at least one compound selected from the group consisting of metal salts of fluorides and nonmetal salts of fluorides. A coating is formed by applying an aqueous solution of any one of the above 1) to 3) and then drying the applied solution to perform a chemical conversion treatment. The coating formed on the surface of the metal foil layer (11) by the chemical conversion treatment has a chromium deposition amount (per side) of 0.1 mg / m 2 ~50mg / m 2 is preferred, and 2 mg / m 2 ~20mg / m 2 is preferred. The thickness of the metal foil layer (11) is preferably 30 to 200 μm, more preferably 50 to 150 μm. By setting the thickness within the above range, sufficient barrier properties and moldability can be obtained.

[0017] The outer resin film layer (12) provides a design to the outer surface of the molded container (2), prevents the surface of the molded container (2) from being scratched or dented, and prevents the metal foil layer (11) from corroding, and also imparts deep-draw formability and stretch-formability to the laminate for molded container (10).

[0018] The second resin film layer (12A) of the outer resin film layer (12) is made of a resin composition containing a first elastomer-modified olefin-based resin having a melting point (Tmp) of 155°C or higher and a crystalline melting energy (ΔH) of 50 J / g or higher, and a second elastomer-modified olefin-based resin having a melting point (Tmp) of 135°C or higher and a crystalline melting energy (ΔH) of 30 J / g or lower. The first elastomer-modified olefin resin and the second elastomer-modified olefin resin are each made of an elastomer-modified homopolypropylene and / or an elastomer-modified random copolymer. The elastomer-modified random copolymer is an elastomer-modified product of a random copolymer (random polypropylene) containing propylene and a monomer other than propylene as a copolymerization component. The copolymerization component (monomer) other than propylene is not particularly limited, but examples thereof include olefin components such as ethylene, 1-butene, 1-hexene, 1-pentene, 4-methyl-1-pentene, and butadiene. The elastomer component is not particularly limited, but it is preferable to use at least one of ethylene-propylene elastomer (EPR), ethylene-1-butene elastomer (EBR), and ethylene-propylene-1-butene elastomer (EPBR).

[0019] The reason why the second resin film layer (12A) is composed of a resin composition containing a first elastomer-modified olefin-based resin having a melting point (Tmp) of 155°C or higher and a crystalline melting energy (△H) of 50 J / g or higher, and a second elastomer-modified olefin-based resin having a melting point (Tmp) of 135°C or higher and a crystalline melting energy (△H) of 30 J / g or lower is as follows. That is, if the melting point of the first elastomer-modified olefin resin is less than 155°C, when the laminate (10) is molded, noticeable whitening occurs over a wide area in the rounded portion of the bottom of the molded container (2) (see Comparative Example 4). If the melting point of the second elastomer-modified olefin resin is less than 135° C., white stripes are formed along the circumferential direction of the rounded portion of the bottom of the molding container 2 during molding of the laminate 10 (see Comparative Example 5). Furthermore, if the crystalline melting energy (ΔH) of the first elastomer-modified olefin resin is less than 50 J / g, the outer resin film layer (12) will be crushed to some extent during the heat sealing (see Comparative Example 6). Furthermore, if the crystalline melting energy (△H) of the second elastomer-modified olefin resin exceeds 30 J / g, streaky whitening occurs along the circumferential direction of the R portion of the bottom of the molding container (2) during molding of the laminate (10) (see Comparative Example 7). Furthermore, if the first elastomer-modified olefin-based resin having a melting point (Tmp) of 155°C or higher and a crystalline melting energy (ΔH) of 50 J / g or higher is not contained, streaky whitening occurs along the circumferential direction of the R portion of the bottom of the molded container (2) during molding of the laminate (10), and the outer resin film layer (12) is easily crushed and tends to have insufficient shape retention (see Comparative Example 2). Furthermore, if the second elastomer-modified olefin resin having a melting point (Tmp) of 135°C or higher and a crystalline melting energy (ΔH) of 30 J / g or less is not contained, significant whitening occurs over a wide area of ​​the R portion of the bottom of the molded container (2) during molding of the laminate (10) (see Comparative Example 1).

[0020] The melting point of the first elastomer-modified olefin-based resin is preferably 155° C. or more and 185° C. or less. The crystalline melting energy of the first elastomer-modified olefin-based resin is preferably 50 J / g or more and 75 J / g or less, more preferably 53 J / g or more and 70 J / g or less. The melting point of the second elastomer-modified olefin-based resin is preferably 135° C. or more and 175° C. or less. The crystalline melting energy of the second elastomer-modified olefin-based resin is preferably 5 J / g or more and 30 J / g or less, more preferably 10 J / g or more and 25 J / g or less, and particularly preferably 10 J / g or more and 20 J / g or less.

[0021] With regard to the first elastomer-modified olefin-based resin and the second elastomer-modified olefin-based resin, the elastomer modification may be performed by graft polymerization, but other modification modes may also be used.

[0022] The first elastomer-modified olefin-based resin and the second elastomer-modified olefin-based resin can be produced, for example, by the following reactor-made method. That is, first, a Ziegler-Natta catalyst, a cocatalyst, propylene and hydrogen are supplied to a first reactor to polymerize homopolypropylene. The resulting homopolypropylene, together with unreacted propylene and Ziegler-Natta catalyst, is then transferred to a second reactor, where additional propylene and hydrogen are added to polymerize the homopolypropylene. The resulting homopolypropylene, together with unreacted propylene and the Ziegler-Natta catalyst, is transferred to a third reactor, where ethylene, propylene and hydrogen are added to polymerize ethylene-propylene elastomer (EPR) by copolymerizing ethylene and propylene. In this manner, the first elastomer-modified olefin-based resin or the second elastomer-modified olefin-based resin is produced. The first elastomer-modified olefin-based resin can be produced in a liquid phase by adding a solvent, and the second elastomer-modified olefin-based resin can be produced in a gas phase by reacting without using a solvent. However, the above is merely one example of the production method, and the first elastomer-modified olefin-based resin and the second elastomer-modified olefin-based resin are not limited to those produced by such a production method.

[0023] In the second resin film layer (12A) of the laminate (10), the content of the second elastomer-modified olefin-based resin is preferably 1 to 50 mass%, more preferably 5 to 30 mass%, and particularly preferably 10 to 25 mass%. If the content of the second elastomer-modified olefin-based resin is less than 1 mass%, whitening may occur when the laminate (10) is molded. On the other hand, if the content of the second elastomer-modified olefin-based resin exceeds 50 mass%, the heat resistance decreases. In the second resin film layer (12A), the content of the first elastomer-modified olefin-based resin is preferably 49 to 99% by mass, more preferably 70 to 95% by mass, and particularly preferably 75 to 90% by mass. If the content of the first elastomer-modified olefin-based resin exceeds 99% by mass, whitening may occur when the laminate (10) is molded. On the other hand, if the content of the first elastomer-modified olefin-based resin is less than 49% by mass, the heat resistance decreases.

[0024] The second resin film layer (12A) preferably has an island-in-a-sea structure. Such an island-in-a-sea structure allows the second resin film layer (12A) to exhibit the conflicting properties of heat resistance and flexibility. In the island-in-a-sea structure, the elastomer components of the first elastomer-modified olefin-based resin and the second elastomer-modified olefin-based resin preferably form fine islands.

[0025] The second elastomer-modified olefin resin preferably has two or more crystallization peaks in a differential scanning calorimetry (DSC) measurement graph. When the second elastomer-modified olefin resin has two crystallization peaks, the higher crystallization peak (crystallization temperature) is preferably 90° C. or higher and the lower crystallization peak (crystallization temperature) is preferably 80° C. or lower. When the second elastomer-modified olefin resin has three or more crystallization peaks, the highest crystallization peak (crystallization temperature) is preferably 90° C. or higher and the lowest crystallization peak (crystallization temperature) is preferably 80° C. or lower.

[0026] In the laminate (10) shown in Fig. 1(a), the second resin film layer (12A) constituting the outer surface of the laminate (10) preferably contains at least one of inorganic fine particles, organic fine particles, and a slip agent in addition to the first elastomer-modified olefin resin and the second elastomer-modified olefin resin. By adding inorganic fine particles, organic fine particles, or a slip agent to the second resin film layer (12A), fine irregularities are formed on the outer surface of the laminate (10) and the area in contact with the mold during molding is reduced, improving the slipperiness, allowing for good molding with a deeper molding depth, and further suppressing whitening during molding. The inorganic fine particles are not particularly limited, but examples thereof include silica, aluminum silicate, barium sulfate, etc. The organic fine particles are not particularly limited, but examples thereof include acrylic resin beads, polystyrene resin beads, etc. The slip agent is not particularly limited, but examples thereof include fatty acid amides such as erucic acid amide, stearic acid amide, oleic acid amide, etc., and waxes such as crystalline wax, polyethylene wax, etc. Instead of or in addition to the addition of the slip agent, a lubricating oil such as silicone oil, rapeseed oil, etc. may be applied to the surface of the laminate (10) during molding.

[0027] In a laminate (10) having an outer resin film layer (12) of a two-layer or three-layer structure as shown in FIG. 1(a)(b), the first resin film layer (12B) arranged on the metal foil layer (11) side is made of a resin composition containing 50% by mass or more of a random copolymer containing propylene as one of the copolymerization components or a polymer of propylene alone (homopolypropylene). In the random copolymer, the copolymerization component (monomer) other than propylene is not particularly limited, but examples thereof include olefin components such as ethylene, 1-butene, 1-hexene, 1-pentene, 4-methyl-1-pentene, and butadiene. When the content of the random copolymer or homopolypropylene is 50% by mass or more, the first resin film layer (12B) is less likely to be crushed when a lid (3) is heat-sealed to a flange (23) of a container (2) formed from the laminate (10) (see FIG. 2), and sufficient shape retention of the container (2) can be ensured, as well as sufficient retort resistance. More preferably, the content of the random copolymer or homopolypropylene in the first resin film layer (12B) is set to 70% by mass or more. The random copolymer containing propylene as one of the copolymerization components is preferably a random copolymer having two or more melting points. In this case, the random copolymer component having a low melting point can further increase the adhesive strength with the metal foil layer (11) and further improve the adhesive performance, and the random copolymer component having a high melting point makes the first resin film layer (12B) less likely to be crushed when the lid (3) is heat-sealed to the flange (23) of the container (2) formed from the laminate (10) (see FIG. 2), thereby ensuring more sufficient shape retention of the container (2). In addition, it is preferable that the first resin film layer (12B) does not have an island-in-sea structure. This has the advantage that, when the laminate (10) is deep-drawn to form the molded container (2), the generation of voids (spaces) at the interface between the olefin resin phase and the elastomer phase in the first resin film layer (12B) can be sufficiently suppressed. In particular, when the first resin film layer (12B) is disposed adjacent to the metal foil layer (11), the above effect is remarkable.

[0028] In the laminate (10) having the outer resin film layer (12) of a three-layer structure as shown in FIG. 1(b), the third resin film layer (12C) constituting the outer surface of the laminate (10) is made of a resin composition having the same structure as the first resin film layer (12B), that is, containing 50% by mass or more of a random copolymer containing propylene as one of the copolymerization components or a polymer of a propylene monolayer (homopolypropylene). By disposing the third resin film layer (12C) on the outer surface of the laminate (10), a container with a more glossy appearance can be obtained. In addition, since the content of the random copolymer or homopolypropylene is 50% by mass or more, the third resin film layer (12C) is less likely to be crushed when the lid (3) is heat-sealed to the flange (23) of the container (2) formed from the laminate (10) (see FIG. 2), and sufficient shape retention of the container (2) can be ensured, as well as sufficient retort resistance. More preferably, the content of the random copolymer or homopolypropylene in the third resin film layer (12C) is set to 70% by mass or more. The random copolymer containing propylene as one of the copolymerization components is preferably a random copolymer having two or more melting points. In this case, the high-melting random copolymer component makes the third resin film layer (12C) less likely to be crushed when the lid (3) is heat-sealed to the flange (23) of the container (2) formed from the laminate (10) (see FIG. 2), and the shape retention of the container (2) can be more sufficiently ensured. Since the third resin film layer (12C) also constitutes the outer surface of the laminate (10), it is preferable to add at least one of inorganic fine particles, organic fine particles, and a slip agent, which gives excellent slipperiness to the outer surface of the laminate (10), making it possible to smoothly mold a greater molding depth, and furthermore, the effect of sufficiently suppressing whitening during molding is obtained.

[0029] The film constituting the outer resin film layer (12) is preferably produced by a molding method such as multi-layer extrusion molding, inflation molding, or T-die cast film molding. The total thickness of the outer resin film layer (12) is preferably set to 20 to 80 μm. By setting the thickness to 20 μm or more, the occurrence of pinholes can be sufficiently prevented, and by setting the thickness to 80 μm or less, the amount of resin used can be reduced, leading to cost reduction. More preferably, the total thickness of the outer resin film layer (12) is set to 30 to 50 μm. When the outer resin film layer has a two-layer structure consisting of a second resin film layer (12A) and a first resin film layer (12B) (see FIG. 1(a)), the ratio of the thickness of the second resin film layer (12A) to the thickness of the first resin film layer (12B) is preferably in the range of 9:1 to 4:6. If the thickness ratio of the second resin film layer (12A) exceeds 9, the lamination strength between the layers (12A) and (12B) may decrease, leading to the risk of peeling. On the other hand, if the thickness ratio of the second resin film layer (12A) is less than 4, the outer resin film layer is less likely to be crushed during heat sealing. When the outer resin film layer has a three-layer structure consisting of a second resin film layer (12A), a first resin film layer (12B) and a third resin film layer (12C) (see FIG. 1(b)), the ratio of the thickness of the second resin film layer (12A), the thickness of the first resin film layer (12B) and the thickness of the third resin film layer (12C) is preferably in the range of 0.5:9:0.5 to 3:4:3.

[0030] The method of laminating the film constituting the first resin film layer (12B) in Fig. 1(a)(b) on the metal foil constituting the metal foil layer (11) is not particularly limited, but includes dry lamination and sandwich lamination (a method in which an adhesive film made of an acid-modified polypropylene resin or the like is extruded, sandwich-laminated between the metal foil and the film, and then heat-laminated with a heated roll). In the case of the dry lamination method, for example, the lamination is performed via an adhesive layer (14) made of a two-component curing type polyester-polyurethane resin adhesive or a polyether-polyurethane resin adhesive (see Fig. 1). The thickness of the adhesive layer (14) is preferably set to 1 to 5 µm, and more preferably set to 1 to 3 µm from the viewpoint of thinning and weight reduction of the laminate for forming container (10).

[0031] A printed layer (15) is formed entirely or partially on the inner surface of the outer resin film layer (12) by gravure printing or the like. This printed layer (15) provides a predetermined display or decoration on the outer surface of the molded container (2). There are no particular limitations on the printed layer (15), but in order to impart a sense of luxury, it is preferable that the background color be a light color such as yellow (gold). This provides a color tone with metallic luster. Instead of the printed layer (15), a coloring component such as a pigment may be added to the outer resin film layer (12).

[0032] The inner resin layer (13) constitutes the inner surface of the molded container (2) (including the upper surface of the flange portion (23)) and is made of, for example, a general-purpose film such as a polypropylene resin (PP) film or a polyethylene resin (PE) film having thermal adhesion, or a composite sheet made by bonding these together. In particular, by making the inner resin layer (13) out of a composite sheet made by bonding general-purpose films such as a polypropylene resin (PP) film and a polyethylene resin (PE) film together, when opening the lid of the package, the polypropylene resin (PP) film and the polyethylene resin (PE) film etc. are easily peeled off from each other, making it possible to open the package with a relatively small force. The thickness of the film or composite sheet constituting the inner resin layer (13) is preferably 100 to 500 μm, and more preferably 200 to 400 μm.

[0033] The metal foil constituting the metal foil layer (11) and the film or composite sheet constituting the inner resin layer (13) are laminated, for example, by a dry lamination method via an adhesive layer (16). For example, a two-component curing type polyester-polyurethane resin adhesive or a polyether-polyurethane resin adhesive is used for the adhesive layer (16). The thickness of the adhesive layer (16) is preferably set to 1 to 5 μm, and more preferably 1 to 3 μm from the viewpoint of making the laminate for a molded container (10) thinner and lighter. The inner resin layer (13) may be formed of a coating layer of epoxy resin, shellac resin, or the like, instead of the above-mentioned film or composite sheet.

[0034] FIG. 2 shows a process for producing a package (4) in which a content (C) such as food is hermetically packed using a formed container (2) formed from the laminate (10) and a lid (3).

[0035] First, the laminate (10) is cut to a predetermined shape and size, and then molded into a cup shape. The laminate (10) is molded by cold forming such as deep drawing or stretch forming. In this way, a molded container (2) as shown in Fig. 2(a) is obtained. The forming container (2) has a bottom wall (21), a peripheral wall (22) rising from the peripheral edge of the bottom wall (21), and a horizontal annular flange (23) extending radially outward from the upper edge of the peripheral wall (22). The shape of the forming container (2) may be a circular, elliptical, oval, approximately square, approximately rectangular, or other cross section, and may be a tapered cylinder whose diameter gradually increases toward the top, or a vertical cylinder. The depth of the forming container (2) is usually set to 15 to 50 mm. Whitening is hardly observed on the outer surface of the molded container (2) formed from the laminate (10), i.e., the outer resin film layer (12). This is because, by making the resin composition of the second resin film layer (12A) of the laminate (10) as described above, the interface between the olefin resin phase and the elastomer component is effectively prevented from peeling off due to stress during molding, resulting in the generation of voids (air gaps).

[0036] Next, as shown in FIG. 2(b), the formed container (2) is filled with the contents (C) such as food, and then the peripheral portion of the lower surface of the lid (3) is heat sealed (thermally fused) to the upper surface of the flange (23) of the formed container (2). The lid (3) used here includes, for example, a metal foil layer made of aluminum foil or the like, a heat-sealable resin film layer made of polypropylene resin (PP) film, polyethylene resin (PE) film, or the like and laminated on the lower surface of the metal foil layer, and an outer resin film layer made of polyester resin (PEs) film, polyamide resin (PA) film, or the like and laminated on the upper surface of the metal foil layer. Also, an opening tab (31) is integrally formed on a part of the outer periphery of the lid (3) so as to protrude outward beyond the flange (23) of the molded container (2) (see FIG. 3). The means for heat sealing (thermal fusion) the lid (3) to the flange (23) of the molded container (2) is not particularly limited, but for example, the lid (3) can be overlapped with the upper surface of the flange (23) at its lower peripheral portion, and the overlapped portions are heated for a predetermined time while applying a predetermined pressure with a hot plate heated to a predetermined temperature (e.g., about 180°C).

[0037] Next, the package (4) obtained in the above step is introduced into a retort sterilization device (5) and subjected to a retort sterilization treatment. This retort sterilization process can also serve as a heat treatment process for eliminating whitening that occurs in a part of the outer resin film layer (12) of the formed container (2). That is, in the formed container (2) obtained by forming the laminate (10) according to the present invention into a cup shape, as described above, the specific resin composition of the second resin film layer (12A) of the laminate (10) prevents whitening of the outer resin film layer (12), but even if slight whitening occurs in a part of the outer resin film layer (12), particularly in a corner part of the boundary between the bottom wall (21) and the peripheral wall (22) that is largely deformed by forming, due to voids (gaps) generated at the interface between the olefin resin matrix and the olefin elastomer, the whitening can be completely eliminated by carrying out this heat treatment. The heating temperature of the package (4) in this step is a temperature equal to or higher than the softening point of the resin of the second resin film layer (12A) of the laminate (10). More preferably, the heating temperature is a temperature equal to or higher than the softening point and lower than the melting point of the resin. By setting the heating temperature to a temperature equal to or higher than the softening point of the resin, the distortion of the laminate (10) caused by molding is alleviated, and voids are easily filled. In addition, by setting the heating temperature to a temperature lower than the melting point of the resin, the shape of the molded container (2) can be maintained even after heating. Specifically, the heating temperature is about 80°C or higher, preferably about 100 to 180°C. The heating time is about 5 minutes to 3 hours. The heat treatment step may of course be other than the retort sterilization step, and may be, for example, a heat treatment in an oven, a immersion treatment in hot water, etc. In the case of a heat treatment other than the retort sterilization step, only the formed container (2) may be heat treated in a step before it is made into the package (4).

[0038] FIG. 3 shows the package (4) after retort sterilization. The illustrated package (4) has a molded container (2) that is free of any whitening due to molding and has a good overall appearance, and can provide consumers with a sense of luxury. EXAMPLES

[0039] Next, an embodiment of the present invention will be described, however, the present invention is not limited to the following embodiment.

[0040] <Example 1> The metal foil layer is made of A8021H-O classified under JIS H4160. A chemical conversion treatment solution consisting of polyacrylic acid, a trivalent chromium compound, water and alcohol is applied to both sides and dried at 180°C to obtain a chromium deposition amount of 5 mg / m2 per side. 2 An aluminum foil having a thickness of 120 μm and having a chemical conversion coating formed thereon was prepared. A 30 μm-thick, three-layered unstretched polypropylene resin film (CPP) was prepared as the outer resin film layer. The film consisted of a first resin film layer 4 μm thick made of an ethylene-propylene random copolymer (R-PP, melting points 152°C, 144°C, crystalline melting energy 57 J / g), a first elastomer-modified olefin-based resin (B-PP1) of 99 mass% ethylene-propylene elastomer-modified homopolypropylene resin copolymerized with ethylene and propylene, having a melting point of 163°C and a crystalline melting energy of 58 J / g, and a second elastomer-modified olefin-based resin (B-PP2) of 99 mass% ethylene-propylene elastomer-modified homopolypropylene resin copolymerized with ethylene and propylene, having a melting point of 163°C and a crystalline melting energy of 58 J / g. The film was formed by co-extrusion using a T-die molding machine so that a 22μm-thick second resin film layer made of a resin composition containing 1% by mass of an ethylene-propylene elastomer modified random copolymer obtained by copolymerizing ethylene and propylene, the ethylene-propylene elastomer modified random copolymer having a melting point of 144°C and a crystalline melting energy of 19 J / g, and a 4μm-thick third resin film layer made of an ethylene-propylene random copolymer (R-PP, melting points 152°C, 144°C, crystalline melting energy 57 J / g) were formed in that order. In addition, 2000 ppm of erucic acid amide was added to the second resin film layer, and 1000 ppm of erucic acid amide and 5000 ppm of silica were added to the first and third resin film layers, respectively. The melting point (Tmp) and crystalline melting energy (ΔH) of each of the above resins were measured under the following measurement conditions. - Temperature increase / decrease speed: 10℃ / min temperature increase / decrease speed from 23℃ to 210℃ Sample weight: 5mg Container: Aluminum pan Equipment: Shimadzu DSC-60A Next, a plain printed layer was formed with yellow ink using a gravure printer over the entire surface of the non-stretched polypropylene resin film on the metal foil layer side. In addition, a composite sheet (layer ratio: 50 μm / 250 μm) of a high density polyethylene resin film (HDPE) and a polypropylene resin film (PP) having a thickness of 300 μm was prepared as the inner resin layer. Then, a non-oriented polypropylene resin film (CPP) was dry laminated to one side of the aluminum foil using a two-component curing polyester-polyurethane resin adhesive with the printed layer facing inward, and the composite sheet was dry laminated to the other side of the aluminum foil using a two-component curing polyester-polyurethane resin adhesive with the high-density polyethylene resin film side facing inward, and the laminate was cured in an environment of 40°C for 5 days to produce the laminate for a molded container of Example 1.

[0041] <Example 2> A laminate for a molded container was prepared in the same manner as in Example 1, except that the resin composition of the second resin film layer was 90 mass% of an ethylene-propylene elastomer modified homopolypropylene resin having a melting point of 163°C and a crystalline melting energy of 58 J / g as the first elastomer modified olefin resin (B-PP1), and 10 mass% of an ethylene-propylene elastomer modified random copolymer having a melting point of 144°C and a crystalline melting energy of 19 J / g as the second elastomer modified olefin resin (B-PP2). This was designated Example 2.

[0042] <Example 3> A laminate for a molded container was prepared in the same manner as in Example 1, except that the resin composition of the second resin film layer was 90 mass% of an ethylene-propylene elastomer modified random copolymer having a melting point of 155°C and a crystalline melting energy of 51 J / g as the first elastomer modified olefin resin (B-PP1), and 10 mass% of an ethylene-propylene elastomer modified random copolymer having a melting point of 144°C and a crystalline melting energy of 19 J / g as the second elastomer modified olefin resin (B-PP2). This was designated Example 3.

[0043] <Example 4> A laminate for a molded container was prepared in the same manner as in Example 1, except that the resin composition of the second resin film layer was 90 mass% of an ethylene-propylene elastomer modified homopolypropylene resin having a melting point of 163°C and a crystalline melting energy of 58 J / g as the first elastomer modified olefin resin (B-PP1), and 10 mass% of an ethylene-propylene elastomer modified random copolymer having a melting point of 136°C and a crystalline melting energy of 18 J / g as the second elastomer modified olefin resin (B-PP2). This was designated Example 4.

[0044] <Example 5> A laminate for a molded container was prepared in the same manner as in Example 1, except that the resin composition of the second resin film layer was 80 mass% of an ethylene-propylene elastomer modified homopolypropylene resin having a melting point of 163°C and a crystalline melting energy of 58 J / g as the first elastomer modified olefin resin (B-PP1), and 20 mass% of an ethylene-propylene elastomer modified random copolymer having a melting point of 144°C and a crystalline melting energy of 19 J / g as the second elastomer modified olefin resin (B-PP2). This was designated Example 5.

[0045] <Example 6> A laminate for a molded container was prepared in the same manner as in Example 1, except that the resin composition of the second resin film layer was 70 mass% of an ethylene-propylene elastomer modified homopolypropylene resin having a melting point of 163°C and a crystalline melting energy of 58 J / g as the first elastomer modified olefin resin (B-PP1), and 30 mass% of an ethylene-propylene elastomer modified random copolymer having a melting point of 144°C and a crystalline melting energy of 19 J / g as the second elastomer modified olefin resin (B-PP2). This was designated Example 6.

[0046] <Example 7> A laminate for a molded container was prepared in the same manner as in Example 1, except that the resin composition of the second resin film layer was 80 mass% of an ethylene-propylene elastomer modified homopolypropylene resin having a melting point of 166°C and a crystalline melting energy of 65 J / g as the first elastomer modified olefin resin (B-PP1), and 20 mass% of an ethylene-propylene elastomer modified random copolymer having a melting point of 144°C and a crystalline melting energy of 19 J / g as the second elastomer modified olefin resin (B-PP2). This was designated Example 7.

[0047] <Example 8> A laminate for a molded container was prepared in the same manner as in Example 1, except that the resin composition of the second resin film layer was 70 mass% of an ethylene-propylene elastomer modified homopolypropylene resin having a melting point of 166°C and a crystalline melting energy of 65 J / g as the first elastomer modified olefin resin (B-PP1), and 30 mass% of an ethylene-propylene elastomer modified random copolymer having a melting point of 144°C and a crystalline melting energy of 19 J / g as the second elastomer modified olefin resin (B-PP2). This was designated Example 8.

[0048] <Example 9> As the outer resin film layer, a 26 μm-thick two-layered non-oriented polypropylene resin film (CPP) was used. The film was formed by co-extrusion using a T-die molding machine so that a first resin film layer of 4 μm thickness made of an ethylene-propylene random copolymer (R-PP, melting points 152°C, 144°C, crystalline melting energy 57 J / g) and a second resin film layer of 22 μm thickness made of a resin composition of 90 mass% of an ethylene-propylene elastomer modified homopolypropylene resin copolymerized with ethylene and propylene having a melting point of 163°C and a crystalline melting energy of 58 J / g as the first elastomer modified olefin resin (B-PP1) and 10 mass% of an ethylene-propylene elastomer modified random copolymer having a melting point of 144°C and a crystalline melting energy of 19 J / g as the second elastomer modified olefin resin (B-PP2) were formed in this order. Then, except for the above, in the same manner as in Example 1, a laminate for a forming container was produced, which was designated as Example 9.

[0049] <Example 10> The first and third resin film layers were each made of homopolypropylene (H-PP, melting point: 165°C, crystalline melting energy: 63 J / g) with a thickness of 4 μm. The first and third resin film layers were each added with 1000 ppm erucic acid amide and 5000 ppm silica. Then, except for the above, in the same manner as in Example 2, a laminate for a forming container was produced, which was designated as Example 10.

[0050] <Comparative Example 1> A laminate for a molded container was prepared in the same manner as in Example 1, except that a 30 μm-thick three-layer structure non-oriented polypropylene resin film (CPP) formed by laminating ethylene-propylene elastomer modified homopolypropylene resin (B-PP1) films having a melting point of 163°C and a crystalline melting energy of 58 J / g was used as the first resin film layer, the second resin film layer and the third resin film layer. This was designated Comparative Example 1.

[0051] <Comparative Example 2> A laminate for a molded container was prepared in the same manner as in Example 1, except that the first elastomer-modified olefin resin (B-PP1) was not added to the second resin film layer, and the second elastomer-modified olefin-based resin (B-PP2) was composed of 100 mass% ethylene-propylene elastomer-modified random copolymer having a melting point of 144°C and a crystalline melting energy of 19 J / g. This was designated Comparative Example 2.

[0052] <Comparative Example 3> A laminate for a molded container was prepared in the same manner as in Example 1, except that the second resin film layer did not contain the second elastomer-modified olefin resin (B-PP2) and consisted of 100 mass% ethylene-propylene elastomer-modified homopolypropylene resin having a melting point of 163°C and a crystalline melting energy of 58 J / g as the first elastomer-modified olefin resin (B-PP1). This was designated Comparative Example 3.

[0053] <Comparative Example 4> A laminate for a molded container was prepared in the same manner as in Example 1, except that the resin composition of the second resin film layer was 90 mass% of an ethylene-propylene elastomer modified random copolymer having a melting point of 145°C and a crystalline melting energy of 50 J / g as the first elastomer modified olefin resin (B-PP1), and 10 mass% of an ethylene-propylene elastomer modified random copolymer having a melting point of 144°C and a crystalline melting energy of 19 J / g as the second elastomer modified olefin resin (B-PP2). This was designated Comparative Example 4.

[0054] <Comparative Example 5> A laminate for a molded container was prepared in the same manner as in Example 1, except that the resin composition of the second resin film layer was 90 mass% of an ethylene-propylene elastomer modified homopolypropylene resin having a melting point of 163°C and a crystalline melting energy of 58 J / g as the first elastomer modified olefin resin (B-PP1), and 10 mass% of an ethylene-propylene elastomer modified random copolymer having a melting point of 130°C and a crystalline melting energy of 14 J / g as the second elastomer modified olefin resin (B-PP2). This was designated Comparative Example 5.

[0055] <Comparative Example 6> A laminate for a molded container was prepared in the same manner as in Example 1, except that the resin composition of the second resin film layer was 90 mass% of an ethylene-propylene elastomer modified random copolymer having a melting point of 155°C and a crystalline melting energy of 49 J / g as the first elastomer modified olefin resin (B-PP1), and 10 mass% of an ethylene-propylene elastomer modified random copolymer having a melting point of 144°C and a crystalline melting energy of 19 J / g as the second elastomer modified olefin resin (B-PP2). This was designated Comparative Example 6.

[0056] <Comparative Example 7> A laminate for a molded container was prepared in the same manner as in Example 1, except that the resin composition of the second resin film layer was 90 mass% of an ethylene-propylene elastomer modified homopolypropylene resin having a melting point of 163°C and a crystalline melting energy of 58 J / g as the first elastomer modified olefin resin (B-PP1), and 10 mass% of an ethylene-propylene elastomer modified random copolymer having a melting point of 158°C and a crystalline melting energy of 44 J / g as the second elastomer modified olefin resin (B-PP2). This was designated Comparative Example 7.

[0057] <Comparative Example 8> A laminate for a molded container was prepared in the same manner as in Example 1, except that the resin composition of the second resin film layer was 99 mass% of an ethylene-propylene elastomer modified homopolypropylene resin having a melting point of 163°C and a crystalline melting energy of 58 J / g as the first elastomer modified olefin resin (B-PP1), and 1 mass% of an ethylene-propylene elastomer (EPR) having a melting point of 40 to 70°C and a crystalline melting energy of 15 J / g as the olefin elastomer. This was designated Comparative Example 8.

[0058] <Comparative Example 9> A laminate for a molded container was prepared in the same manner as in Example 1, except that the resin composition of the second resin film layer was 90 mass% of an ethylene-propylene elastomer modified homopolypropylene resin having a melting point of 163°C and a crystalline melting energy of 58 J / g as the first elastomer modified olefin resin (B-PP1), and 10 mass% of an ethylene-propylene elastomer (EPR) having a melting point of 40 to 70°C and a crystalline melting energy of 15 J / g as the olefin elastomer. This was designated Comparative Example 9.

[0059] <Comparative Example 10> A laminate for a molded container was prepared in the same manner as in Example 1, except that the resin composition of the second resin film layer was 80 mass% of an ethylene-propylene elastomer modified homopolypropylene resin having a melting point of 163°C and a crystalline melting energy of 58 J / g as the first elastomer modified olefin resin (B-PP1), and 20 mass% of an ethylene-propylene elastomer (EPR) having a melting point of 40 to 70°C and a crystalline melting energy of 15 J / g as the olefin elastomer, and this was designated Comparative Example 10.

[0060] <Comparative Example 11> A laminate for a molded container was prepared in the same manner as in Example 1, except that the resin composition of the second resin film layer was 70 mass% of an ethylene-propylene elastomer modified homopolypropylene resin having a melting point of 163°C and a crystalline melting energy of 58 J / g as the first elastomer modified olefin resin (B-PP1), and 30 mass% of an ethylene-propylene elastomer (EPR) having a melting point of 40 to 70°C and a crystalline melting energy of 15 J / g as the olefin elastomer. This was designated Comparative Example 11.

[0061] [Container creation] Next, the laminates for molded containers of Examples 1 to 10 and Comparative Examples 1 to 11 were cut to predetermined shapes and sizes to prepare blanks, and a small amount of siloxane was applied to both sides of each blank. After that, a deep drawing process was performed using a mold (manufactured by Amada Co., Ltd.) consisting of male and female molds to prepare round cup-shaped containers with flanges (bottom diameter 52 mmφ, opening diameter 65 mmφ, height 30 mm, flange width 8 mm).

[0062] [Making the lid] On the other hand, a 12 μm thick polyethylene terephthalate resin (PET) film was dry laminated as an outer resin layer to one side of a 20 μm thick aluminum foil made of A1N30H-O classified under JIS H4160 using a two-component curing polyester-polyurethane resin adhesive, and a 30 μm thick linear low-density polyethylene resin (LLDPE) film was dry laminated as a heat-sealable resin layer to the other side of the aluminum foil using a two-component curing polyester-polyurethane resin adhesive, and the resulting laminate was cured for 5 days in an environment of 40°C to produce a lid laminate. The resulting laminate was cut to the required shape and size to fit the flange, creating a lid with a tear tab.

[0063] [Packaging Creation] After pouring 70 ml of water into each of the above containers, the above lids were placed on the top of the flanges of the containers with the non-oriented polypropylene resin film (CPP) surface in contact with each other, and heat sealing (thermal fusion) was performed by pressing a donut-shaped hot plate (outer diameter 90 mmφ, inner diameter 74 mmφ) heated to 200°C against the polymerized surfaces with a pressure of 150 kgf for 3 seconds. Thus, a package was obtained.

[0064] [Verification of packaging appearance] The containers of each package obtained were visually inspected to see whether the outer resin film layer had whitened and whether the outer resin film layer of the flange had been crushed. The inspection results are shown in Tables 1 and 2 below, together with the composition of the second resin film layer of the laminate, which is the molding material of each container. In the column "Whitening during molding" in Tables 1 and 2, those in which no or almost no whitening was observed in the outer resin film layer of the container were marked with "◎", those with little whitening were marked with "○", those in which whitening occurred in stripes along the circumferential direction in the R part of the bottom of the container were marked with "△", and those in which whitening was noticeable over a wide area in the R part of the bottom of the container were marked with "×". In the column "Flange crush" in Tables 1 and 2, those in which no crushing was observed in the outer resin film layer of the flange of the container due to heat sealing of the lid were marked with "◎", those with almost no crushing were marked with "◯", those with some crushing were marked with "△", and those with noticeable crushing were marked with "×". In addition, in Tables 1 and 2, ethylene-propylene random copolymer is represented as "R-PP", homopolypropylene as "H-PP", the first elastomer-modified olefin-based resin as "B-PP1", the second elastomer-modified olefin-based resin as "B-PP2", and ethylene-propylene elastomer as "EPR".

[0065] [Table 1]

[0066] [Table 2]

[0067] As is clear from Table 1, the whitening phenomenon during molding was improved in the laminates of Examples 1 to 10. Furthermore, in the cases of Examples 1 to 10, no crushing occurred in the outer resin film layer of the flange of the container after the lid was heat-sealed. On the other hand, as shown in Table 2, in the laminates of Comparative Examples 1, 3 and 8 to 11, a strong whitening phenomenon was observed over a wide area in the rounded portion of the bottom of the molded container. In the laminate of Comparative Example 2, the outer resin film layer of the flange of the container was crushed after the lid was heat-sealed, and the shape retention was insufficient. In addition, in the laminate of Comparative Example 2, stripes of whitening occurred along the circumferential direction in the R part of the bottom of the molded container. In the laminate of Comparative Example 4, severe whitening was observed over a wide area in the R portion of the bottom of the molded container, and the outer resin film layer of the flange of the container was crushed to a certain extent after the lid was heat-sealed. In the laminates of Comparative Examples 5 and 7, there was no crushing of the outer resin film layer of the container flange after the lid was heat-sealed, but streaky whitening occurred along the circumferential direction of the R portion of the bottom of the molded container. In the case of the laminate of Comparative Example 6, whitening due to molding was almost completely prevented, but the outer resin film layer of the flange of the container was crushed to some extent after the lid was heat sealed. Based on the above verification results, it is believed that crushing of the outer resin film layer of the container flange is affected by both the melting point and crystalline melting energy of the resin components, and it can be seen that crushing is less likely to occur when the melting point (the higher melting point when B-PP1 and B-PP2 are contained) is 155°C or higher and the crystalline melting energy (the weighted average of the crystalline melting energies of both when B-PP1 and B-PP2 are contained, calculated by the content ratio) is 40 J / g or higher (more preferably 50 J / g or higher). [Industrial Applicability]

[0068] The present invention relates to a molded container for sealing and packaging food and the like, which has excellent long-term storage properties and a good appearance. To It can be suitably used. [Explanation of symbols]

[0069] (2): Molded container (23): Flange (3): Lid (4):Packaging (5): Retort sterilization equipment (10): Laminate for molded containers (11):Metal foil layer (12): Outer resin film layer (12A): Second resin film layer (12B): First resin film layer (12C): Third resin film layer (15):Printing layer (C):Contents

Claims

1. A molded container formed by molding a laminate for a molded container into a cup shape and having a flange on an opening periphery, The laminate for a forming container includes a metal foil layer and an outer resin film layer laminated on one of both sides of the metal foil layer that will become an outer side of a container, the outer resin film layer has a multi-layer structure of two or more layers including at least a first resin film layer containing 50% by mass or more of a random copolymer containing propylene as one of the copolymerization components or a polymer of a propylene monomer, and a second resin film layer made of a resin composition including a first elastomer-modified olefin-based resin having a melting point of 155° C. or more and a crystalline melting energy of 50 J / g or more, and a second elastomer-modified olefin-based resin having a melting point of 135° C. or more and a crystalline melting energy of 30 J / g or less, the first resin film layer being interposed between the metal foil layer and the second resin film layer; the first elastomer-modified olefin-based resin and the second elastomer-modified olefin-based resin each comprise an elastomer-modified homopolypropylene resin and / or an elastomer-modified random copolymer, The elastomer-modified random copolymer is an elastomer-modified random copolymer containing propylene as one of the copolymerization components, A molded container, wherein in the second resin film layer, the total content of the first elastomer-modified olefin-based resin and the second elastomer-modified olefin-based resin is 50 mass% or more.

2. A packaging body comprising a lid joined to the flange of a molded container described in claim 1 filled with contents so as to cover the opening of the molded container.

Images