Molded container and method for manufacturing the same

Abstract

To provide a molded container comprising a laminate having a metal foil layer and a resin layer and provided with a display on an outside of the container by printing has no risk of losing the display even when sterilizing it under pressurizing and heating and no risk of causing deviation and deformation in the display.SOLUTION: A molded container 20 is molded so that a laminate 10 having a metal foil layer 11, a protective resin layer 12 laminated on one surface of the metal foil layer and a sealant layer 13 laminated on the other surface of the metal foil layer, is arranged with the protective resin layer to be on an outer side of the container. A photo-curable ink 4 is coated at least on a part of an outer surface of the molded container constituted by a surface of the protective resin layer and cured by irradiation with light to thereby form a print layer 24.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to a formed container formed by molding a laminate having a metal foil layer and a resin layer, and more particularly to a formed container suitably used when retort food is used as a content and a method for manufacturing the same.

Background Art

[0002] As a container for hermetically packaging retort food, a laminate having a metal foil layer, a protective resin layer laminated on one surface of the metal foil layer, and a sealant layer laminated on the other surface of the metal foil layer is formed into a three-dimensional shape such as a cup shape so that the protective resin layer faces the outside of the container. The formed container is known. According to the above-described formed container, there are advantages such as being lighter in weight, having a lower cost, and having excellent quality maintainability compared to a metal can or the like. Here, in the case of retort food, in a state of being hermetically packaged with a formed container and a lid material, pressure heating sterilization (retort sterilization) by boiling treatment or the like is performed. However, if a display consisting of characters, patterns, etc. such as the name, characteristics, and ingredient list of the content is directly printed on the outer surface of the formed container, the printed layer may peel off after retort sterilization and the display may disappear. Therefore, usually, instead of directly printing on the outer surface of the formed container, a seal with the required display printed on the surface is attached to the outer surface of the formed container after retort sterilization, or an outer box for accommodating the formed container is prepared and the required display is printed on the outer surface of the outer box. However, when using a seal or an outer box, there is a problem in that it increases by one extra step after filling and sealing the content, and materials other than the container are required, so that the manufacturing is laborious and costly.

[0003] Therefore, for example, as described in Patent Document 1 below, a formed container has been proposed which is formed by molding a laminate in which a printed layer is formed inside a transparent resin layer constituting the outer surface of the container.

Prior Art Documents

Patent Documents

[0004] Patent Document 1 Japanese Patent Application Laid-Open No. 2017-196841 Summary of the Invention Problems to be Solved by the Invention

[0005] However, in the case of the formed container described in Patent Document 1 or the like, distortion may occur in the printed layer during molding, and the displayed characters, patterns, etc. may be displaced or deformed. In particular, for the display provided on the outer surface of the side wall of a cup-shaped container, since the degree of distortion of the printed layer due to molding increases, the displayed characters may become unreadable, or the appearance may be significantly impaired.

[0006] The present invention has been made in view of the above problems, and as a formed container made of a laminate having a metal foil layer and a resin layer and provided with a printed display on the outside of the container, there is no risk of the display disappearing even when pressure heating sterilization is performed, and also, it is an object of the present invention to provide a container in which there is no risk of displacement or deformation in the display. Means for Solving the Problems

[0007] In order to achieve the above object, the present invention comprises the following aspects.

[0008] 1) A formed container obtained by molding a laminate having a metal foil layer, a protective resin layer laminated on one surface of the metal foil layer, and a sealant layer laminated on the other surface of the metal foil layer, with the protective resin layer on the outside of the container, The formed container is a cup-shaped one having a bottom wall and side walls rising from the periphery of the bottom wall. The side walls are formed as tapered cylindrical walls with diameters gradually increasing upward. An upward annular step is formed at the upper part of the outer surface of the side walls. A printed layer is formed by applying a photocurable ink to the outer surface of the formed container constituted by the surface of the protective resin layer and curing it by light irradiation. The Outer surface portion of the side walls below the annular step A formed container.

[0009] 2) The formed container according to 1), wherein the photocurable ink contains a main agent made of a photocurable resin, a photopolymerization initiator, and a pigment.

[0010] 3) The formed container according to 2), wherein the photocurable resin contains a polyfunctional (meth)acrylate.

[0011] 4) The formed container according to 3), wherein the polyfunctional (meth)acrylate contains a urethane (meth)acrylate having at least two (meth)acryloyl groups in the molecule and a (meth)acrylate having at least three (meth)acryloyl groups in the molecule (excluding those having a urethane bond in the molecule).

[0012] 5 ) The laminate On the surface of the protection resin layer is formed and has a wetting tension of the surface measured in accordance with JIS K6768 of 38 ~60 mN / m is printing receptive layer and further has , The The formed container according to any one of 1) to 4 ), wherein the printing layer is formed on the surface of the printing receptive layer.

[0013] 6 ) The formed container according to any one of 1) to 5 ), wherein the printing layer is a multicolor printing layer made of two or more colors of photocurable ink.

[0014] 7 ) A step of forming a formed container by molding a laminate having a metal foil layer, a protective resin layer laminated on one surface of the metal foil layer, and a sealant layer laminated on the other surface of the metal foil layer, such that the protective resin layer is on the outside of the container; , a cup-shaped one having a bottom wall, tapered cylindrical side walls rising from the periphery of the bottom wall and having diameters gradually increasing upward, and a downward annular step formed at the upper part of the outer surface of the side walls. a step of applying a photocurable ink to the outer surface of the formed container; and a step of forming a printing layer by irradiating the applied photocurable ink with light to cure it. A method for manufacturing a formed container. The outer surface portion of the side walls below the annular step and a step of forming a printing layer by irradiating the applied photocurable ink with light to cure it. A method for manufacturing a formed container. A method for manufacturing a formed container, comprising:

Advantages of the Invention

[0015] According to the formed container of 1) above, on the The outer surface portion of the side walls below the annular step of the formed container consisting of the surface of the protective resin layer, a photocurable ink is applied and cured by light irradiation, so that a printing layer excellent in durability and adhesion is formed. Therefore, even when the container is filled and sealed with contents such as food and then subjected to pressure heating sterilization with steam or hot water, there is no risk of the display by the printing layer disappearing. Further, the above printing layer is formed on the The outer surface portion of the side walls below the annular step of the formed container, and there is no risk of displacement or deformation in the display by the printing layer, so that problems such as the displayed characters becoming unreadable or the appearance being significantly damaged do not occur. Further, according to the formed container of 1) above, since it is formed in a cup shape and a printing layer made of photocurable ink is formed on the portion of the outer surface of the side walls below the annular step, for example, characters representing the name, features, ingredients, etc. of food or the like as the contents, and designs with excellent designability can be clearly displayed. Furthermore, according to the formed container of 1) above, a plurality of them can be stored and transported in a stacked state, and in the stacked state, the portion of the outer surface of the side walls of the formed container below the annular step does not come into contact with the side wall portion of the lower formed container, and since a printing layer is formed on the lower portion, rubbing of the printing layer during stacking is avoided.

[0016] The above 2 ) to 4 ) of the formed container, the photocurable ink contains at least a main agent made of a photocurable resin, a photoinitiator and a pigment, and the photocurable resin contains a polyfunctional (meth)acrylate. Therefore, a printing layer excellent in durability and adhesion can be obtained. In particular, when the polyfunctional (meth)acrylate contains a urethane (meth)acrylate having at least two (meth)acryloyl groups in the molecule and a (meth)acrylate having at least three (meth)acryloyl groups in the molecule (excluding those having a urethane bond in the molecule), a printing layer extremely excellent in durability and adhesion can be obtained. Therefore, there is no risk of the display by the printing layer disappearing due to pressure heating sterilization, and it can be suitably used as a container for retort food.

[0017] The above 5 ) of the formed container, according to protection the surface of the resin layer 38 a printing receptive layer having a wetting tension of 30 to 60 mN / m is formed, so that the adhesion of the printing layer formed on the surface of this printing receptive layer can be improved.

[0018] The above 6According to the formed container of [[ ]], since a multicolor printing layer made of a photocurable ink of two or more colors is formed on its outer surface, the display by the printing layer becomes easier to see, and the design of the container is also enhanced.

[0019] Said 7 ) according to the manufacturing method of the formed container, a laminate having a metal foil layer, a protective resin layer, and a sealant layer is In a cup shape formed, and on the The outer surface portion of the side walls below the annular step of the obtained formed container, a photocurable ink is applied and cured by light irradiation, so that a printing layer excellent in durability and adhesion is formed. Therefore, even when pressure heating sterilization is performed after filling and sealing the container with contents such as food, there is no risk that the display by the printing layer will disappear. Also, the above printing layer is formed on the The outer surface portion of the side walls below the annular step of the formed container, and there is no risk of displacement or deformation in the display by the printing layer, so problems such as the displayed characters becoming unreadable or the appearance being significantly damaged do not occur.

Brief Description of the Drawings

[0020]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Modes for Carrying Out the Invention

[0021] Hereinafter, embodiments of the present invention will be described with reference to FIGS. 1 to 5.

[0022] FIG. 1 shows the layer structure of a laminate used as a molding material for a molded container according to the present invention. The laminate (10) shown in FIG. 1 has a metal foil layer (11), a protective resin layer (12) laminated on one surface of the metal foil layer (11), and a sealant layer (13) laminated on the other surface of the metal foil layer (11). A printing receptive layer (14) is formed on the surface of the protective resin layer (12).

[0023] The metal foil layer (11) functions as a barrier layer for protecting the contents from gas, water vapor, light, etc. As the metal foil constituting the metal foil layer (11), aluminum foil, iron foil, stainless steel foil, copper foil, nickel foil, etc. can be used. However, considering cost, barrier function, corrosion resistance, and formability, aluminum foil is preferable. The aluminum foil may be either a pure aluminum foil or an aluminum alloy foil, and may be either soft or hard. However, the soft materials (O materials) of the A8000 series or A3000 series classified by JIS H4160 are particularly excellent in formability. For example, A8021H-O or A8079H-O can be preferably used. It is preferable to form an underlayer (anchor coat layer) (not shown) by chemical conversion treatment or the like on both surfaces of the metal foil layer (11) to enhance the bondability with the protective resin layer (12) and the sealant layer (13). As the treatment liquid, various known ones can be used without particular limitation. For example, a coating liquid composed of phosphoric acid, polyacrylic acid (acrylic resin), chromium (III) salt compound, water, and alcohol is preferable. The thickness of the metal foil layer (11) is not particularly limited, but is preferably about 5 to 300 μm, and more preferably about 40 to 150 μm. By setting the thickness of the metal foil layer (11) within the above range, sufficient barrier properties and moldability can be obtained.

[0024] The protective resin layer (12) constitutes the outer surface of the forming container (20) and plays a role in enhancing and protecting the corrosion resistance and the like of the metal foil layer (11), and is made of various known thermosetting resin films. Examples of the thermosetting resin film include stretched or non-stretched films made of polyolefin resins such as polypropylene resin (PP), low-density polyethylene resin (LDPE), linear low-density polyethylene resin (LLDPE), and high-density polyethylene resin (HDPE), stretched or non-stretched films made of polyester resins such as polyethylene terephthalate resin (PET), polybutylene terephthalate resin (PBT), and polyethylene naphthalate resin (PEN), and stretched or non-stretched films made of polyamide resins such as 6-nylon resin (PA6). Although the thickness of the protective resin layer (12) is not particularly limited, it is preferably about 20 to 150 μm, more preferably about 25 to 100 μm, in consideration of formability, durability, corrosion resistance, manufacturing cost, heat influence during sealing, and the like. The lamination of the protective resin layer (12) and the metal foil layer (11) is performed, for example, by a dry lamination method through an adhesive layer (not shown). As the adhesive layer, for example, a two-component curable polyurethane resin-based adhesive is suitable, and particularly a two-component curable polyester-polyurethane resin-based adhesive and / or a two-component curable polyether-polyurethane resin-based adhesive are preferable.

[0025] The sealant layer (13) forms the inner surface of the formed container (20) and imparts heat-sealability to the formed container (20), and is made of various known thermoplastic resin films. As the thermoplastic resin film, for example, an unstretched film made of polyolefin resins such as polypropylene resin (PP), low-density polyethylene resin (LDPE), linear low-density polyethylene resin (LLDPE), and high-density polyethylene resin (HDPE) is preferably used. Further, as the sealant layer (13), a laminated film in which the polypropylene resin and the polyethylene resin are bonded together by, for example, a co-extrusion method can also be used. In this case, the thickness of the polypropylene resin layer is usually about 45 to 500 μm, preferably about 140 to 370 μm, and the thickness of the polyethylene resin layer is usually about 5 to 100 μm, preferably about 10 to 80 μm. Further, the thickness of the sealant layer (13) itself is not particularly limited, but considering the corrosion resistance of the metal thin layer (11) by the contents, the strength of the formed container (20), and the cost, it is usually about 50 to 600 μm, preferably about 150 to 450 μm. The lamination of the sealant layer (13) and the metal foil layer (11) is performed, for example, by a dry lamination method through an adhesive layer (not shown). As the adhesive layer, for example, a two-component curable polyurethane resin-based adhesive, a two-component curable polyether resin-based adhesive, a polyacrylic-based adhesive, etc. can be used. In particular, a two-component curable polyester-polyurethane resin-based adhesive and / or a two-component curable polyether-polyurethane resin-based adhesive are preferable in terms of heat resistance and retort resistance.

[0026] The printing receptive layer (14) is for enhancing the adhesion between the protective resin layer (12) and the printing layer (24) that form the outer surface of the formed container (20). This printing receptive layer (14) can be formed by performing a frame treatment, a corona treatment, etc. on the surface of the protective resin layer (12). Considering the adhesion between the printing demand layer (14) and the printing layer (24), the wetting tension (JIS K6768) (hereinafter, the same applies when referring to the wetting tension) of its surface is usually 40 mN / m or more and 60 mN / m or less, preferably 42 mN / m or more and 55 mN / m or less.

[0027] Figure 2 shows a formed container (20) formed by molding the above laminate (10). The illustrated formed container (20) is a cup-shaped one including a circular bottom wall (21) when viewed from the plane, a cylindrical side wall (22) rising from the periphery of the bottom wall (21), and a horizontal flange (23) extending radially outward from the upper edge of the side wall (22) (see also Fig. 4). On the lower surface of the bottom wall (21), an annular step (211) facing the center side is formed at an intermediate position in the radial direction, and the portion of the bottom wall (21) inside this annular step (211) is raised in a trapezoidal shape. The planar shape of the bottom wall (21) may be circular, or may be elliptical, substantially square, or the like. The side wall (22) is formed in a tapered cylindrical shape whose diameter gradually increases upward. Also, a downward annular step (221) is formed on the upper part of the outer surface of the side wall (22). Therefore, a plurality of these formed containers (20) can be stored, transported, etc. in a state of being stacked vertically. In the stacked state, the lower part of the outer surface of the side wall (22) of the formed container (20) below the annular step (221) does not come into contact with the side wall (22) portion of the lower formed container (20). Thus, if a printing layer (24) is formed on the lower part, rubbing of the printing layer (24) during stacking is avoided (see Fig. 4, etc.). The shape of the formed container (20) is not limited to the cup shape as described above, and can be appropriately set according to the contents and the like. Further, the formed container (20) is formed by deep drawing, flanging, or the like. For example, when the contents are small such as tablets, it can also be formed by embossing (embossing molding).

[0028] Figure 3 shows the procedure for forming the printing layer (24) on the outer surface of the side wall (22) of the above formed container (20). Specifically, it includes a step of applying a photocurable ink (4) to the outer surface of the side wall (22) of the formed container (20) (see Fig. 3(a)), and a step of forming the printing layer (24) by irradiating light to the applied photocurable ink (4) to cure it (see Fig. 3(b)). Examples of the printing method include offset printing and inkjet printing. Fig. 3(a) shows the printing process by offset printing. The photocurable ink (4) on the surface of the blanket cylinder (3) transferred from the plate cylinder (not shown) is transferred to the outer surface of the side wall (22) of the molding container (20) that rotates in contact with the blanket cylinder (3), thereby performing printing. The printing may also be multicolor printing using two or more photocurable inks. In this case, the display by the printing layer (24) becomes even easier to see, and the design property of the molding container (20) is also enhanced.

[0029] The photocurable ink contains a main agent made of a photocurable resin, a photoinitiator, and a pigment, and is excellent in quick-drying property and cures by irradiating light for a short time after coating.

[0030] Considering the adhesion of the printing layer (24) to the outer surface of the molding container (20) (the surface of the protective resin layer (12)), the photocurable resin constituting the main agent preferably contains polyfunctional (meth)acrylate. In this specification, "polyfunctional (meth)acrylate" refers to a photocurable compound having at least two acryloyl groups and / or methacryloyl groups in the molecule.

[0031] The polyfunctional (meth)acrylate is not particularly limited as long as it is a known one as a photocurable resin for photocurable ink. Specific examples include urethane (meth)acrylate, epoxy (meth)acrylate, polyester (meth)acrylate, and other polyfunctional (meth)acrylates.

[0032] Examples of the urethane (meth)acrylate include reaction products of a polymer of a polyol and a polyisocyanate (isocyanate group-terminated prepolymer) and a hydroxyl group-containing (meth)acrylate. Examples of the polyol include high molecular weight polyols such as polyester polyol, polyether polyol, polycarbonate diol, and polybutadiene glycol, and low molecular weight polyols such as ethylene glycol, propylene glycol, tetramethylene glycol, cyclohexanedimethanol, 3-methyl-1,5-pentanediol, and 1,6-hexanediol. Examples of the polyisocyanate include xylylene diisocyanate, isophorone diisocyanate, and 2,2,4-trimethylhexamethylene diisocyanate. Examples of the hydroxyl group-containing (meth)acrylate include hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, and hydroxybutyl (meth)acrylate. Two or more of each raw material may be combined.

[0033] Examples of the epoxy (meth)acrylate include addition reaction products of an epoxy resin having at least two epoxy groups in the molecule and (meth)acrylic acid. Examples of the epoxy resin include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol E type epoxy resin, cresol novolak type epoxy resin, phenol novolak type epoxy resin, hydrogenated bisphenol A type epoxy resin, hydrogenated bisphenol F type epoxy resin, hydrogenated bisphenol E type epoxy resin, hydrogenated cresol novolak type epoxy resin, and hydrogenated phenol novolak type epoxy resin, and two or more of them may be combined. Specific examples of the epoxy (meth)acrylate include ethylene oxide-modified bisphenol type di(meth)acrylate, propylene oxide-modified bisphenol type di(meth)acrylate, and their hydrogenated products.

[0034] Examples of the polyester (meth) acrylate include reaction products of a polymer of a dibasic acid and a polyhydric alcohol with an epoxy group-containing (meth) acrylate. Examples of the dibasic acid include succinic acid, adipic acid, sebacic acid, maleic anhydride, fumaric acid, phthalic acid, isophthalic acid, terephthalic acid, hexahydrophthalic anhydride, and naphthalenedicarboxylic acid, etc. Examples of the polyhydric alcohol include the above-mentioned low molecular weight polyol. Each raw material may be a combination of two or more kinds.

[0035] Examples of the polyfunctional (meth) acrylate other than those described above include di (meth) acrylates such as ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, tricyclodecane dimethanol di (meth) acrylate, 1,6 - hexanediol di (meth) acrylate, 1,9 - nonanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, glycerin di (meth) acrylate, polyethylene glycol di (meth) acrylate, and polypropylene glycol di (meth) acrylate; tri (meth) acrylates such as pentaerythritol tri (meth) acrylate, propylene oxide-modified trimethylolpropane tri (meth) acrylate, ethylene oxide-modified trimethylolpropane tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, and tris (acryloxyethyl) isocyanurate; tetra (meth) acrylates such as ditrimethylolpropane tetra (meth) acrylate, pentaerythritol tetra (meth) acrylate, and ethylene oxide-modified pentaerythritol tetra (meth) acrylate; (meth) acrylates having 5 to 6 (meth) acryloyl groups in the molecule such as dipentaerythritol hexa (meth) acrylate, etc. These may be a combination of two or more kinds.

[0036] As the polyfunctional (meth)acrylate, a combination of a urethane (meth)acrylate having at least two (meth)acryloyl groups in the molecule and a (meth)acrylate having at least three (meth)acryloyl groups in the molecule (excluding those having a urethane bond in the molecule) is preferable in terms of the adhesion and heat resistance of the printing layer.

[0037] Examples of the photopolymerization initiator include various known benzophenone-based initiators, acetophenone-based initiators, and benzoin ether-based initiators, etc., and two or more kinds may be combined.

[0038] Examples of the pigment include various known white pigments, black pigments, yellow pigments, orange pigments, brown pigments, red pigments, blue pigments, and green pigments, etc.

[0039] The contents of the main agent, photopolymerization initiator, and pigment in the photocurable ink are not particularly limited, but usually, in terms of solid content conversion, the photopolymerization initiator is about 0.1 to 30 parts by mass and the pigment is about 1 to 80 parts by mass with respect to 100 parts by mass of the main agent.

[0040] The photocurable ink may contain various known mono(meth)acrylates as a reactive diluent as needed. Specifically, for example, hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate, hydroxybutyl (meth)acrylate, polycaprolactone (meth)acrylate, polypropylene glycol mono(meth)acrylate, polyethylene glycol mono(meth)ac Relates, polyethylene glycol - propylene glycol - mono (meth) acrylate, polyethylene glycol - tetramethylene glycol - mono (meth) acrylate, propylene glycol - polybutylene glycol - mono (meth) acrylate, 1,4 - cyclohexanedimethanol monoacrylate, ethoxylated isocyanuric acid triacrylate, ε - caprolactone - modified tris - (2 - acryloxyethyl) isocyanurate, phenoxy (meth) acrylate, phenoxydiethylene glycol (meth) acrylate, ethylene oxide - modified (meth) acrylate, ethylene oxide - modified nonylphenol (meth) acrylate, ethylene oxide - modified nonylphenol (meth) acrylate, methoxytriethylene glycol (meth) acrylate and phenyl glycidyl ether (meth) acrylate, etc. may be mentioned, and two or more kinds may be combined.

[0041] As the light irradiated to the photocurable ink to cure the same, electromagnetic waves with a wavelength of about 500 nm or less such as visible light, ultraviolet rays, X - rays, and γ - rays may be mentioned. In the case of Fig. 3(b), the formed container (20) placed upside down on the conveyor (5) is irradiated with light (7) from a light source such as a mercury lamp (6) disposed at a predetermined distance above it.

[0042] Figs. 4 and 5 show the formed container (20) in a state where the printing layer (24) is formed by the above - mentioned printing process. The printing layer (24) is formed on the outer surface of the side wall (22) of the formed container (20), and the required display is constituted by the printing layer (24). Examples of the display include characters and patterns representing the name, characteristics, components, manufacturer, etc. of the contents. Since this printing layer (24) is formed by printing on the outer surface of the side wall (22) of the formed container (20) obtained by molding the laminate (10), there is no occurrence of distortion or the like associated with molding as in the case of forming a printing layer on the laminate before molding, and the display will not be displaced or unreadable. In addition to being formed on the outer surface of the side wall (22) of the formed container (20), the printing layer (24) may also be formed on the lower surface of the bottom wall (21) or the lower surface of the flange (23). Although illustration is omitted, after the above-mentioned forming container (20) is filled with food or the like as the content, a lid material is applied so as to cover the upper opening thereof, whereby a package in which the content is hermetically packaged is obtained. As the lid material, for example, a laminate having at least a metal foil layer and a sealant layer laminated on the lower surface of the metal foil layer is used, and it is heat-sealed on the upper surface of the flange (23) of the forming container (20). Furthermore, as a subsequent step, the obtained package may be subjected to pressure heating sterilization (retort sterilization) by boiling treatment or the like. In this case, the outer surface of the forming container (20) is exposed to hot water or steam, but since the printing layer (24) made of the photocurable ink (4) is excellent in resistance to and adhesion to hot water and steam, there is no risk that the printing layer (24) will peel off and the display will disappear.

Example

[0043] Next, specific examples of the present invention will be described, but the present invention is not limited to these examples.

[0044] <Example 1> On both sides of an aluminum foil (= metal foil layer) with a thickness of 120 μm made of A8021H-O defined in JIS H4160, a coating liquid composed of phosphoric acid, polyacrylic acid (acrylic resin), chromium (III) salt compound, water and alcohol is applied so that the chromium adhesion amount per side is 10 mg / m 2 After coating, drying is performed at 180 ° C to form an underlayer. Next, on one surface of the aluminum foil, a two-component curable polyether-polyurethane resin-based adhesive is applied so that the solid content adhesion amount is 3 g / m 2 After coating, drying is performed at 100 ° C, and then a non-stretched polypropylene resin film (CPP) with a thickness of 30 μm (= protective resin layer) is laminated. Also, on the other surface of the aluminum foil, the two-component curable polyurethane resin-based adhesive is 3 g / m 2After applying so as to obtain the above, drying is performed at 100 °C, and then a coextruded film (=sealant layer) with a thickness of 300 μm composed of a polyethylene resin film with a thickness of 50 μm and an unstretched polypropylene resin film with a thickness of 250 μm is laminated such that the polypropylene resin layer faces the aluminum foil side, and after aging treatment for 10 days in an environment at 40 °C, a laminate is obtained.

[0045] A molding material obtained by cutting out the above laminate into a square with a size of 200 cm × 200 cm is subjected to deep drawing using a deep drawing molding machine (manufactured by Amada Co., Ltd.) such that the unstretched polypropylene resin film is on the outside of the container, thereby producing a cup-shaped molded container. The deep drawing was performed under the conditions of a press speed of 35 spm and a wrinkle suppression pressure of 0.4 MPa. The molded container had dimensions such that the inner diameter of the bottom wall was 75 mm, the inner diameter of the flange was 80 mm, and the depth was 35 mm. Further, after molding, the flange was trimmed so that its width became 5 mm. Then, corona treatment was performed on the surface of the unstretched polypropylene resin film on the outside of the container, and the wetting tension of the surface was adjusted to 44 mN / m.

[0046] Then, UV ink was applied to the outer surface of the side wall of the above molded container using a gravure offset printing machine. The UV ink used was one containing 70 parts by mass of a urethane acrylate resin having two acryloyl groups as the main component, 6 parts by mass of benzophenone and 15 parts by mass of pentaerythritol triacrylate as a photopolymerization initiator, and 9 parts by mass of aniline black (black) as a pigment (manufactured by T&K TOKA Co., Ltd., trade name "T-12"). Next, the applied UV ink was irradiated with light for 5 seconds at an irradiation distance of 10 cm using a mercury lamp (output 240 W / cm), thereby forming a printed layer on the outer surface of the side wall of the molded container. The printed molded container thus obtained was designated as Example 1.

[0047] <Example 2> A laminate was obtained in the same manner as in Example 1, and a cup-shaped formed container was produced under the same conditions as in Example 1. Next, the surface of the unstretched polypropylene resin film on the outside of the container was subjected to corona treatment to adjust the wetting tension of the surface to 42 mN / m. Then, the UV ink according to Example 1 was applied to the outer surface of the side wall under the same conditions as in Example 1 to form a printed layer.

[0048] <Example 3> A laminate was obtained in the same manner as in Example 1, and a cup-shaped formed container was produced under the same conditions as in Example 1. Next, the surface of the unstretched polypropylene resin film on the outside of the container was subjected to corona treatment to adjust the wetting tension of the surface to 40 mN / m. Then, the UV ink according to Example 1 was applied to the outer surface of the side wall under the same conditions as in Example 1 to form a printed layer.

[0049] <Example 4> A laminate was obtained in the same manner as in Example 1, and a cup-shaped formed container was produced under the same conditions as in Example 1. Next, the surface of the unstretched polypropylene resin film on the outside of the container was subjected to corona treatment to adjust the wetting tension of the surface to 38 mN / m. Then, the UV ink according to Example 1 was applied to the outer surface of the side wall under the same conditions as in Example 1 to form a printed layer.

[0050] <Comparative Example 1> Using the laminate obtained in the same manner as in Example 1, a cup-shaped formed container was produced under the same conditions as in Example 1. Next, a non-UV ink based on a vinyl chloride-vinyl acetate copolymer resin was applied to the outer surface of the side wall, and then dried at 150°C for 3 seconds to form a printed layer, thereby producing a printed formed container.

[0051] <Verification of Adhesion of Printed Layer> The adhesion of the printed layer of the formed containers of Examples 1 to 4 and Comparative Example 1 before retort sterilization and the adhesion after heat treatment at 120°C for 30 minutes using a retort sterilizer were tested. The test was conducted by attaching a Nichiban adhesive tape with a width of 25 mm to the printed layer of the formed containers of Examples 1 to 4 and Comparative Example 1, leaving it for 10 minutes with a 2 kg weight placed on top, and then peeling off the adhesive tape to visually check whether the ink on the printed layer was peeled off. As a result, in the cases of Examples 1 and 2, regardless of the presence or absence of retort treatment, there was no adhesion on the adhesive surface of the adhesive tape, and no peeling marks were observed on the printed layer of the formed container. In the case of Example 3, without retort treatment, there was no adhesion on the adhesive surface of the adhesive tape, and no peeling marks were observed on the printed layer of the formed container. After retort treatment, some peeling was observed on the printed layer, but it was within the range of no practical problem. In the case of Example 4, without retort treatment, some peeling was observed on the printed layer, but it was within the range of no practical problem. On the other hand, after retort treatment, peeling was observed on the printed layer. On the other hand, in Comparative Example 1, regardless of the presence or absence of retort treatment, peeling marks were observed on the printed layer of the formed container.

Industrial Applicability

[0052] This invention is formed by molding a laminate having a metal foil layer and a resin layer, and can be suitably used as a formed container for retort foods.

Explanation of Reference Numerals

[0053] (10): Laminate (11): Metal foil layer (12): Protective resin layer (13): Sealant layer (14): Printing receiving layer (20): Formed container (21): Bottom wall (22): Side wall (23): Flange (24): Printed layer (4): Photo-curable ink (7): Light

Claims

1. A formed container obtained by deep drawing or flanging a laminate having a metal foil layer, a protective resin layer laminated on one surface of the metal foil layer, and a sealant layer laminated on the other surface of the metal foil layer, wherein the protective resin layer faces the outside of the container, the metal foil layer is made of aluminum foil, the formed container is in the shape of a cup having a bottom wall and a side wall rising from the periphery of the bottom wall, the side wall is in the shape of a tapered cylinder whose diameter gradually increases upward, an annular downward step is formed at the upper part of the outer surface of the side wall, a printing receptive layer is formed by subjecting the outer surface of the formed container to frame treatment or corona treatment, A formed container, wherein a photocurable ink is applied to a portion of the outer surface of the side wall of the formed container constituted by the surface of the printing receptive layer below the annular step and cured by light irradiation to form a printing layer.

2. The formed container according to Claim 1, wherein the photocurable ink contains a main agent made of a photocurable resin, a photoinitiator, and a pigment.

3. The formed container according to Claim 2, wherein the photocurable resin contains a polyfunctional (meth)acrylate.

4. The formed container according to Claim 3, wherein the polyfunctional (meth)acrylate contains a urethane (meth)acrylate having at least two (meth)acryloyl groups in the molecule and a (meth)acrylate having at least three (meth)acryloyl groups in the molecule (excluding those having a urethane bond in the molecule).

5. The formed container according to any one of Claims 1 to 4, wherein the printing receptive layer has a surface wetting tension of 38 to 60 mN / m measured in accordance with JIS K6768.

6. The formed container according to any one of Claims 1 to 5, wherein the printing layer is a multicolor printing layer formed of two or more colors of photocurable ink.

7. A step of forming a formed container in the shape of a cup having a bottom wall, a tapered cylindrical side wall rising from the periphery of the bottom wall and gradually increasing in diameter upward, and a downward annular step formed at the upper part of the outer surface of the side wall, by deep drawing or flanging a laminate having a metal foil layer made of aluminum foil, a protective resin layer laminated on one surface of the metal foil layer, and a sealant layer laminated on the other surface of the metal foil layer, with the protective resin layer facing the outside of the container, A step of forming a printing-receiving layer by performing frame treatment or corona treatment on the outer surface of the formed container; A step of applying a photocurable ink to a portion below the annular step on the outer surface of the side wall of the formed container constituted by the surface of the printing-receiving layer; A step of forming a printing layer by irradiating light to the applied photocurable ink to cure it, and A method for manufacturing a formed container.

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