Laminated material for lid, lid and package

Abstract

To provide a laminated material for a lid that comprises at least a surface protection layer, a printing ink layer, a barrier layer made of a metal foil, and a sealing layer, and that does not cause defects such as misalignment, abrasion, or fallout on a printed surface when force such as friction or impact is applied through the surface protection layer or when the material is greatly deformed in water.SOLUTION: A printed anchor coat layer 13 is interposed between a printed ink layer 12 and a barrier layer 14, and a composition based on aromatic polyester is used as an anchor coat agent constituting the printed anchor coat layer 13.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a lid laminate for forming a lid for sealing the opening of a container containing contents, a lid formed from the laminate, and a package obtained by sealing the opening of a container containing contents with the lid. The contents can include various foods including beverages, as well as medicines, chemicals, etc. [Background technology]

[0002] Conventionally, as a package for distributing food products such as beverages that require a certain degree of shelf life in a product form on the market, there has been known a package that comprises a container made of a synthetic resin molded product or the like and that opens upward, and a lid that is heat-sealed to the opening edge of the container in which the food is contained.

[0003] As for the lid used for the above-mentioned package, for example, as described in Patent Documents 1 to 3, there are known lids formed from a lid laminate having at least a surface protective layer, a barrier layer (substrate layer) made of metal foil, and a sealing layer made of a heat-sealable resin. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2001-219958 A [Patent Document 2] Patent No. 6310269 [Patent Document 3] Patent No. 6318926 Summary of the Invention [Problem to be solved by the invention]

[0005] Incidentally, a printed ink layer may be provided on the outer surface of the barrier layer of a lid for the purpose of displaying information about the contents of the package or for providing a design such as advertising. However, depending on the storage environment and usage conditions of the lid and package, the printed surface may become misaligned, scratched, or fall off.

[0006] The above problems can also be caused by moisture that comes into contact with the surface of the lid. For example, when the contents are foods, medicines, chemicals, or other products that are prone to change or deteriorate even at room temperature, the packages are stored in a refrigerator at a low temperature of about 10°C or less. If the humidity is high at this time, condensation occurs on the surface of the lid or container, and this condensed water can penetrate into the inside of the lid over time and also into the interface between the printing ink layer and the barrier layer, reducing the adhesion between the two layers.

[0007] The decrease in adhesion can cause the following problem. When the package after refrigerated storage is transported on a conveyer belt, packed in a cardboard box, or displayed in a store after being opened, some kind of external force such as strong friction or impact may be applied to the surface of the lid, or the lid itself may be significantly deformed. This can cause the printed surface on the surface of the lid to shift, become scratched, or fall off, damaging the appearance.

[0008] It is desirable that the above problem does not occur, for example, when the package is immersed in ice water for a certain period of time in order to cool it, and the lid is deformed by contact with the ice.

[0009] In view of the above, an object of the present invention is to provide a lid laminate comprising at least a surface protective layer, a printed ink layer, a barrier layer made of metal foil, and a sealing layer, which does not cause the printed surface to shift, become scratched, fall off, or the like, even when the surface protective layer is subjected to external forces such as friction or impact, or is deformed by being immersed in water for a certain period of time. [Means for solving the problem]

[0010] As a result of investigations, the inventors have found that the above-mentioned problems can be solved by forming a surface protective layer of a laminate material forming a lid with an overprint coating agent, interposing a printed anchor coating layer between the printed ink layer and the barrier layer of the laminate material, and forming this printed anchor coating layer with a specified polyester-based anchor coating agent. That is, the present invention relates to the following lid laminate material, lid, and packaging body.

[0011] 1) A laminate for forming a lid to be heat-sealed to the opening edge of a container containing contents, comprising, from the outside, at least a surface protection layer made of an overprint coating agent, a printed ink layer, a printed anchor coating layer made of an anchor coating agent, a barrier layer made of metal foil, and a sealing layer made of a heat-sealable resin, characterized in that the anchor coating agent is made of a composition based on an aromatic polyester.

[0012] 2) The lid laminate according to 1), wherein the aromatic polyester has at least one of a residue derived from an aromatic dicarboxylic acid and a residue derived from an aliphatic diol.

[0013] 3) The lid laminate according to 1) or 2), characterized in that the aromatic dicarboxylic acid residue contains a residue derived from isophthalic acid.

[0014] 4) The lid laminate according to any one of 1) to 3), characterized in that the aliphatic diol residues contain a residue derived from a branched aliphatic diol having a total carbon number of 5 to 10 and a residue derived from a linear aliphatic diol having a total carbon number of 1 to 5.

[0015] 5) The aromatic polyester has a residue derived from an aromatic dicarboxylic acid and a residue derived from an aliphatic diol, The aromatic dicarboxylic acid residue includes a residue derived from isophthalic acid, The laminated material for lids according to any one of 1) to 4), characterized in that the aliphatic diol residues contain a residue derived from a branched aliphatic diol having a total carbon number of 5 to 10 and a residue derived from a linear aliphatic diol having a total carbon number of 1 to 5.

[0016] 6) The lid laminate material according to any one of 1) to 5), characterized in that the overprint coating agent is at least one selected from the group consisting of a cellulose-based overprint coating agent, a synthetic resin-based overprint coating agent, and a natural product-based overprint coating agent, the cellulose-based overprint coating agent contains at least one of nitrocellulose, cellulose acetate, cellulose propionate, and cellulose acetate-butyrate as a binder resin, the synthetic resin-based overprint coating agent contains at least one of epoxy resin, polyurethane resin, chlorinated polyolefin resin, acrylic resin, vinyl chloride-vinyl acetate copolymer, and polyester as a binder resin, and the natural product-based overprint coating agent contains shellac resin as a binder resin.

[0017] 7) A lid laminate according to any one of 1) to 6), characterized in that the printing ink layer contains an active energy ray non-curable binder resin consisting of at least one of shellac resin, nitrocellulose, cellulose acetate, cellulose propionate, cellulose acetate butyrate, epoxy resin, polyurethane resin, chlorinated polyolefin resin, polyamide resin, acrylic resin, vinyl chloride-vinyl acetate copolymer, and polyester.

[0018] 8) A lid to be heat-sealed to the opening edge of a container containing contents, the lid being formed from any one of the lid laminate materials 1) to 7).

[0019] 9) A package comprising a container containing the contents and a lid as described in 8) heat-sealed to the opening edge of the container. Effect of the Invention

[0020] The lid laminate of 1) is characterized in that the surface protective layer is composed of an overprint coating agent, and the printing anchor coat layer interposed between the printing ink layer and the barrier layer is composed of an aromatic polyester anchor coat agent. The lid laminate of 2) is characterized in that the aromatic polyester that forms the base of the anchor coat agent has at least one of a residue derived from an aromatic dicarboxylic acid and a residue derived from an aliphatic diol. The lid laminate of 3) is characterized in that the aromatic dicarboxylic acid contains a residue derived from isophthalic acid. The lid laminate of 4) is characterized in that the aliphatic diol residue contains a residue derived from a branched aliphatic diol having a total of 5 to 10 carbon atoms and a residue derived from a linear aliphatic diol having a total of 1 to 5 carbon atoms. In addition, the lid laminate of 5) is characterized in that the aromatic polyester that forms the base of the anchor coating agent contains a residue derived from isophthalic acid, a residue derived from a branched diol having a total carbon number of 5 to 10, and a residue derived from a linear diol having a total carbon number of 1 to 5. Here, the residue derived from isophthalic acid has a structure that is less rigid in terms of symmetry than the residue derived from terephthalic acid, and the residue derived from the branched diol has a bulky structure based on the side chain. Therefore, the aromatic polyester has relatively poor crystallinity and is rich in hydrophobicity. Therefore, it is considered that the printed anchor coating layer has both flexibility and water resistance. From the above, the lid laminates of 1) to 5) can prevent problems such as displacement, peeling, and falling off of the printed ink layer even when external forces such as friction and impact are applied to the surface of the lid formed from the laminate, or when the lid is immersed in water for a certain period of time and deforms. Hereinafter, such a characteristic may be referred to as "printed layer resistance."

[0021] The lid laminate 6) has a surface protective layer made of at least one selected from the group consisting of a cellulose-based overprint coating agent, a synthetic resin-based overprint coating agent, and a natural product-based overprint coating agent, and therefore has good print layer resistance. In particular, the cellulose-based overprint coating agent has relatively high water resistance, and therefore has better print layer resistance.

[0022] 7) The laminated material for lids contains a non-active energy ray curable binder resin such as shellac resin in the printing ink layer, so that the binder resin reliably absorbs and fixes the colorant regardless of the type or amount of colorant added.

[0023] The lid 8) is formed from any one of the lid laminates 1) to 7), so even if external forces such as friction or impact are applied to its surface, or the lid is deformed when immersed in water for a certain period of time, the printed ink layer does not shift, peel, fall off, or have other problems.

[0024] The package 9) is a sealed product in which the lid 8) is heat-sealed to the opening edge of a container containing the contents, and even if external forces such as friction or impact force are applied to the surface of the lid, or if the lid is deformed when immersed in water for a certain period of time, the printed ink layer does not shift, peel, fall off, or other problems. [Brief description of the drawings]

[0025] [Figure 1] 1A-1D are enlarged partial cross-sectional views showing four embodiments of the capping laminate according to the present invention; [Diagram 2] FIG. 1(a) is a perspective view showing one embodiment of a lid according to the present invention, and (b) and (C) are vertical sectional views showing two embodiments of a packaging body according to the present invention. [Diagram 3] FIG. 2 is a schematic diagram of a sliding test device used to evaluate the resistance of a printed layer of a lid laminate. [Figure 4] FIG. 1 is a schematic diagram of a shaking device used to evaluate the resistance of a printed layer of a lid in a package. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026] Hereinafter, the lid laminate (1) according to the present invention, the lid (2) formed from the laminate (1), and the package (4) formed by sealingly packaging the contents (C) using the lid (2) and a container (3) will be described in detail with reference to Figures 1 to 4. However, the scope of the present invention is not limited to these drawings.

[0027] <Laminated material for lid (1)> FIG. 1 is a partially enlarged cross-sectional view showing four embodiments of the laminate for covering (1). The lid laminate (1) in FIG. 1(a) includes, in order from the outside (upper side of the figure), a surface protection layer (11), a printed ink layer (12), a printed anchor coat layer (13), a barrier layer (14), an inner anchor coat layer (15), a buffer layer (16), and a seal layer (17) which is the innermost layer. The surface protection layer (11) is made of an overprint coating agent and forms the outermost layer of the lid laminate (1) and the lid (2) (hereinafter referred to as the "overprint coat layer (11)"). In this embodiment, the printed ink layer (12) is an intermittent layer, and the overprint coat layer (11) is partially adhered to the printed anchor coat layer (13). The inner anchor coat layer (15) and the buffer layer (16) are optional, and one or both of them can be omitted. The capping laminate (1) of FIG. 1(b) is an embodiment in which the printed ink layer (12) in the capping laminate (1) of FIG. 1(a) is made to be a continuous layer. The lid laminate (1) of FIG. 1(c) is an embodiment in which the inner anchor coat layer (15) and the buffer layer (16) of the lid laminate (1) of FIG. 1(b) are omitted. The lid laminate (1) of FIG. 1(d) is an embodiment in which an embossed pattern (18) is formed on the innermost surface of the seal layer (17) of the lid laminate (1) of FIG. 1(a).

[0028] <Overprint Coat Layer (11)> The overprint coat layer (11) is a protective layer and a water-resistant layer of the lid laminate (1). This overprint coat layer (11) makes it difficult for water that comes into contact with the outermost surface of the lid (2) to reach the printed ink layer (12), and ensures the printed layer resistance of the printed ink layer (12) against external forces and deformations applied to the lid (2), and also prevents defects such as cracks and pinholes in the barrier layer (14) caused by these. The overprint coating layer (11) is made of any of various known overprint coating agents, which are compositions obtained by dissolving or dispersing any of various known binder resins in a solvent. The binder resin may be at least one selected from the group consisting of natural product-based overprint coating agents such as shellac resin, synthetic resin-based overprint coating agents, and cellulose-based overprint coating agents. Examples of synthetic resin-based overprint coating agents include overprint coating agents based on epoxy resin, polyurethane resin, chlorinated polyolefin resin, acrylic resin, vinyl chloride-vinyl acetate copolymer, and polyester (unsaturated copolymer polyester, saturated copolymer polyester, etc.). Examples of the cellulose-based overprint coating agent include overprint coating agents based on cellulose nitrate, cellulose acetate, cellulose propionate, and cellulose acetate-butyrate. Among these, in terms of print layer resistance, cellulose-based overprint coating agents are preferred, and nitrocellulose and / or cellulose acetate are particularly preferred. Examples of the solvent include toluene, xylene, acetone, methyl ethyl ketone, ethyl acetate, butyl acetate, propyl acetate, methanol, ethanol, isopropyl alcohol, and propylene glycol monomethyl ether (hereinafter, the same applies when referring to the "solvent"). Examples of the curing agent include polyisocyanate compounds, polyepoxy compounds, polyoxazoline compounds, ketimine compounds, and melamine compounds (hereinafter, the same applies when referring to the "curing agent"). The overprint coating layer (11) can be formed by applying an overprint coating agent onto the printing ink layer (12) and drying it usually at 80 to 170° C. The amount of coating is not particularly limited, but for example, the amount of solid content is usually 0.3 to 1 g / m 2 , preferably 0.4 to 0.7 g / m 2 That's fine. The number of layers in the overprint coating layer (11) is not limited, and it may be a single coat or a multi-coat of two or more layers. The multi-coat may be composed of the same type of overprint coating agent, or may be composed of two or more of the same or different types of overprint coating agents. The thickness of the overprint coating layer (11) is not particularly limited, and is usually 0.3 to 2 μm, preferably 0.4 to 1.5 μm, in consideration of the strength as a protective layer and the barrier function as a water-resistant layer.

[0029] <Printing ink layer (12)> The printing ink layer (12) is a layer that provides information about the contents (C) and a design on the outermost surface of the lid (2), and is made of various known printing inks. The printing ink is a composition containing a binder resin and a colorant, and includes both active energy ray non-curable and active energy ray curable inks. The binder resin may be a non-active energy ray curable binder resin and / or an active energy ray curable binder resin. Examples of the active energy ray include visible light, ultraviolet light, electron beams, and X-rays. Examples of non-curable active energy ray binder resins include shellac resins, nitrocellulose, cellulose acetate, cellulose propionate, and cellulose acetate / butyrate, epoxy resins, polyurethane resins, chlorinated polyolefin resins, polyamide resins, acrylic resins, vinyl chloride-vinyl acetate copolymers, and polyesters (unsaturated copolymer polyesters, saturated copolymer polyesters, etc.). Examples of the active energy ray curable binder resin include, as radical polymerization type, various known di(meth)acrylates, tri(meth)acrylates, and tetra(meth)acrylates, as well as poly(meth)acrylates such as (meth)acrylates having 5 to 6 (meth)acryloyl groups in the molecule. The poly(meth)acrylates include various known modified poly(meth)acrylates such as urethane (meth)acrylates, epoxy (meth)acrylates, and polyester (meth)acrylates. Examples of cationic polymerization type or anionic polymerization type include alicyclic epoxy compounds, glycidyl epoxy compounds, oxetane compounds, vinyl ether monomers, and the like. For the active energy ray-curable binder resin, at least one selected from the group consisting of various known radical polymerization initiators, cationic polymerization initiators, and anionic polymerization initiators can be used as a photopolymerization initiator according to the type of the binder resin. Examples of the radical polymerization initiator include benzophenone-based initiators, acetophenone-based initiators, and benzoin-based initiators. As the binder resin, a non-curable active energy ray binder resin can be suitably used, especially when a pigment-based coloring material is added. When an active energy ray curable binder resin is used, the colored pigment blocks particularly short-wavelength active energy rays such as visible light, UV rays, and X-rays, and the binder resin cannot be cured sufficiently, resulting in some areas where the ink does not adhere, which may cause the ink to bleed. On the other hand, in the case of a non-curable active energy ray binder resin, the above-mentioned problems do not occur, and the binder resin reliably contains and adheres to the coloring material regardless of the type and amount of coloring material added, forming a good printing ink layer (12). Examples of the coloring agent include pigments and / or dyes. Examples of the pigments include organic or inorganic pigments such as titanium dioxide, zinc oxide, gloss white, parlite, barium carbonate, calcium carbonate, precipitated silica, aerosil, talc, alumina white, mica, synthetic calcium silicate, magnesium carbonate, barium carbonate, carbon black, magnetite, and red iron oxide. The size of the pigment is not particularly limited, but considering the peeling resistance (relative to the upper limit) and color development (relative to the lower limit), the average primary particle size may be, for example, usually 0.1 to 5 μm, preferably 0.5 to 3 μm. On the other hand, examples of the dyes include anthraquinone dyes, azo dyes, and quinoline dyes. The content of the coloring agent is not particularly limited, but it may be usually 0.5 to 40% by weight, preferably 2 to 10% by weight. The printing ink may optionally contain solvents, hardeners, curing catalysts and other additives. As the solvent, toluene, ethyl acetate, and methyl ethyl ketone are particularly preferable for the active energy ray non-curable binder resin. Also, for the active energy ray curable binder resin, various known (meth)acrylates that can be regarded as reactive diluents may be combined. Examples of the curing catalyst include metal carboxylate catalysts, organotin catalysts, and amine catalysts. Examples of the additives include surfactants and plasticizers, silane coupling agents, and other antistatic agents, which will be described later. The printed ink layer (12) can be formed by a known printing method such as gravure printing, offset printing, or flexographic printing, and may be either monochromatic or multicolor. The total thickness of the printed ink layer (12) is not particularly limited, but from the viewpoint of the resistance of the printed layer, it is usually 0.5 to 4 μm, preferably 0.8 to 3 μm.

[0030] <Printed anchor coat layer (13)> The printed anchor coat layer (13) is a layer that bonds the printed ink layer (12) and the barrier layer (14), and increases the adhesion between the printed ink layer and the barrier layer to prevent printing bleeding, and by being interposed between the two layers, it prevents a decrease in the adhesion between the printed ink layer (12) and the barrier layer (14) even if water that has come into contact with the surface of the overprint coat layer (11) reaches the printed ink layer (12). Therefore, the printed layer resistance of the lid (2) is increased, and even if an external force such as friction or impact is applied to the outermost surface of the lid (2) or the lid (2) is excessively deformed in water, the printed ink layer (12) does not suffer from problems such as displacement, scratching, or falling off.

[0031] The anchor coating agent constituting the printed anchor coating layer (13) (hereinafter also referred to as the "outer anchor coating agent") is made of a composition based on an aromatic polyester, and this aromatic polyester is preferably a polycondensation product of an aromatic dicarboxylic acid and an aliphatic diol.

[0032] The aromatic polyester has at least one of a residue derived from an aromatic dicarboxylic acid and a residue derived from an aliphatic diol (preferably both), and may optionally have residues other than these two residues.

[0033] The aromatic dicarboxylic acid residue includes an isophthalic acid residue. In the present specification, isophthalic acid also includes isophthalic acid derivatives. Examples of the isophthalic acid derivatives include diesters of isophthalic acid and lower monools having about 1 to 3 carbon atoms. Examples of the lower monools include methanol, ethanol, and propanol. Either or both of isophthalic acid and isophthalic acid derivatives can be used.

[0034] The residue derived from isophthalic acid is equivalent to the remaining group obtained by removing one or two hydroxyl groups from the two carboxyl groups of isophthalic acid, and is represented by the formula (a1): -C(=O)-R 1 -X 1 (In each formula, R 1 isophthalic acid nucleus, X 1indicates -C(=O)- or -COOH.

[0035] The aliphatic diol-derived residues include residues derived from branched aliphatic diols having a total of 5 to 10 carbon atoms (hereinafter sometimes abbreviated as "branched diols") and residues derived from linear aliphatic diols having a total of 1 to 5 carbon atoms (hereinafter sometimes abbreviated as "linear diols") (hereinafter sometimes abbreviated as "linear diol-derived residues").

[0036] The branched diol-derived residue is equivalent to the remaining group obtained by removing one or two hydrogen atoms from two hydroxyl groups of the branched diol, and is represented by the formula (b): -OR 2 -X 2 (In the formula, R 2 Each of X represents a branched alkylene group having 5 to 10 carbon atoms. 2 represents -O- or -OH.) Examples of the branched diol include 2-ethyl-1,3-hexanediol, 2-butyl-2-ethyl-1,3-propanediol, 2,4-diethyl-1,5-pentanediol, 2,2,4-trimethyl-1,3-pentanediol, 2-methyl-1,8-octanediol, and neopentyl glycol.

[0037] The linear diol-derived residue is equivalent to the remaining group obtained by removing one or two hydrogen atoms from the two hydroxyl groups of the linear diol, and is represented by the formula (c): -OR 3 -X 3 (In the formula, R 3 represents a linear alkylene group having 1 to 5 carbon atoms, and X 3 represents -O- or -OH.) The linear diol is not particularly limited as long as it has a total carbon number of 1 to 5, and examples thereof include methanediol, ethylene glycol, n-propylene glycol, n-butanediol, and n-pentanediol.

[0038] The aromatic polyester may contain other residues derived from aromatic dicarboxylic acids and aliphatic diols. Reaction components that provide such residues include, for example, polycarboxylic acids other than aromatic dicarboxylic acids, polyols other than aliphatic diols, hydroxycarboxylic acids, and lactones. Examples of polycarboxylic acids include aliphatic dicarboxylic acids such as maleic acid, maleic anhydride, fumaric acid, glutaric acid, adipic acid, azelaic acid, and sebacic acid; alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid; and aliphatic tricarboxylic acids such as trimellitic acid, trimellitic anhydride, pyromellitic, and pyromellitic anhydride, which may be diesters of lower alcohols. Examples of polyols include polyethylene glycol, polypropylene glycol, cyclohexanedimethanol, glycerin, trimethylolpropane, trimethylolethane, pentaerythritol, diglycerin, hydroxypivalic acid neopentyl glycol ester, ditrimethylolpropane, and ditrimethylolethane. Examples of hydroxycarboxylic acids include glycolic acid, lactic acid, hydroxybutyric acid, hydroxypropionic acid, and hydroxypivalic acid. Examples of lactones include β-butyrolactone, δ-valerolactone, and ε-caprolactone.

[0039] When the total amount of residues contained in the aromatic polyester is taken as 1 mole, the ratio of the residues derived from the aromatic dicarboxylic acid, the aliphatic diol residues, and the residues derived from the optional reaction components is not particularly limited. Taking into consideration the resistance of the printed layer, the ratio is usually 30 to 70 mol %, approximately 70 to 30 mol %, and less than 10 mol %, respectively.

[0040] The amount of isophthalic acid-derived residues in the aromatic dicarboxylic acid-derived residues is not particularly limited, but considering the resistance of the printed layer, it may be 90 to 100 mol % when the aromatic dicarboxylic acid-derived residue is taken as 1 mol. On the other hand, 10 to 0 mol % may be residues other than isophthalic acid residues, and examples of such residues include residues derived from phthalic anhydride, orthophthalic acid, terephthalic acid, naphthalenedicarboxylic acid, and derivatives thereof. Examples of such derivatives include diesters with lower monools.

[0041] The total amount of the branched diol-derived residues and the linear diol-derived residues in the aliphatic diol-derived residues is not particularly limited, but considering the resistance of the printed layer, it is usually 90 to 100 mol % when the aliphatic diol-derived residue is taken as 1 mol. On the other hand, 10 to 0 mol % may be residues other than both the branched diol-derived residues and the linear diol-derived residues. Examples of such residues include residues derived from hexanediol, heptanediol, octanediol, etc.

[0042] The ratio of the branched diol-derived residue to the linear diol-derived residue is not particularly limited, but when each of the two residues is taken as 1 mole, the former is usually about 30 to 70 mol % and the latter is usually about 70 to 30 mol %.

[0043] The aromatic polyester can be produced by various known methods.Specific examples of the method include a method of simultaneously (dehydration) condensation reacting the aromatic dicarboxylic acid including isophthalic acid, the aliphatic diol including the branched aliphatic diol and the linear aliphatic diol, and, if necessary, the optional reaction component, or a method of successively (dehydration) condensation reacting the aromatic dicarboxylic acid including isophthalic acid, the aliphatic diol including the branched aliphatic diol and the linear aliphatic diol, and, if necessary, the optional reaction component.

[0044] In the aromatic polyester, the ratio of the aromatic dicarboxylic acid, the aliphatic diol, and the optional reactive component when the total amount of reactive components is 1 mole is not particularly limited, but taking into consideration the resistance of the printed layer, the ratios are usually about 30 to 70 mole %, about 70 to 30 mole %, and 0 to 10 mole %, respectively.

[0045] The amount of isophthalic acid in the aromatic dicarboxylic acid is not particularly limited, but considering the resistance of the printed layer, it may be 90 to 100 mol % when the aromatic dicarboxylic acid is taken as 1 mol. On the other hand, 10 to 0 mol % may be an aromatic dicarboxylic acid other than isophthalic acid, such as phthalic anhydride, orthophthalic acid, terephthalic acid, naphthalenedicarboxylic acid, and derivatives thereof. Such derivatives include diesters with lower monools.

[0046] The total amount of branched diol-derived and linear diol in the aliphatic diol is not particularly limited, but when the resistance of the printed layer is taken as 1 mole of the aliphatic diol, it is usually 90 to 100 mol %. On the other hand, 10 to 0 mol % may be an aliphatic diol other than the branched diol and linear diol, such as hexanediol, heptanediol, and octanediol. The ratio of the branched diol and linear diol is not particularly limited, but when both are taken as 1 mole, the former is usually about 30 to 70 mol %, and the latter is usually about 70 to 30 mol %.

[0047] The condensation reaction conditions are not particularly limited, and usually, the reaction temperature is about 150 to 250°C, and the reaction time is about 5 to 10 hours, but these are examples. The condensation reaction can be carried out under normal pressure or reduced pressure. A catalyst may be used during the reaction. Examples of the catalyst include germanium dioxide, germanium tetraethoxide, germanium tetra-n-butoxide, antimony trioxide, dibutyltin oxide, zinc acetate (dihydrate), monobutyltin oxide, dibutyltin oxide, and titanium tetrabutoxide.

[0048] The main chain structure and residues of the aromatic polyester are identified and quantified, and the reactants are identified and quantified by various known means (1H-NMR, 13C-NMR, various COSY, IR, GC / MS, etc.).

[0049] The physical properties of the aromatic polyester are not particularly limited, but taking into consideration the resistance of the printed layer, the glass transition temperature (JIS K7121-2012) should be -30°C or higher and 80°C or lower, preferably -10°C or higher and 50°C or lower, and the number average molecular weight (referring to the polystyrene equivalent value in the gel permeation chromatography (GPC) method) should usually be 5,000 to 100,000.

[0050] The outer surface anchor coating agent may contain the above-mentioned hardener and additives such as a surfactant, a plasticizer, and a silane coupling agent for the purpose of increasing the resistance of the printed layer. Examples of the surfactant include anionic surfactants, cationic surfactants, amphoteric surfactants, and nonionic surfactants. By using a surfactant, the surface tension of the printed anchor coat layer (13) can be adjusted, and for example, printing voids (non-printed areas of the printing ink) can be avoided. Examples of the plasticizer include alkyl esters of adipate, alkyl esters of phthalate, alkyl esters of phosphoric acid, alkyl esters of trimellitic acid, etc. By using a plasticizer, the hardness of the printed anchor coat layer (13) can be adjusted, making it possible to prevent the printing from fading or falling off. Examples of the silane coupling agent include γ-chloropropyltrimethoxysilane, vinyltrichlorosilane, vinyltriethoxysilane, vinyl-tris(β-methoxyethoxy)silane, γ-methacryloxypropyltrimethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, and γ-glycidoxypropyltrimethoxysilane, etc. Use of a silane coupling agent can improve the adhesion between the printed anchor coat layer (13) and the barrier layer (14). The contents of the curing agent and additives in the outer surface anchor coating agent are not particularly limited, but usually, each may be about 5 to 30% by weight in terms of solid content.

[0051] The printed anchor coat layer (13) can be formed by applying an outer surface side anchor coat agent to one side of the barrier layer (14) and drying it at, for example, 70 to 90° C. The thickness of the printed anchor coat layer (13) is not particularly limited, and taking into consideration the printed layer resistance and the adhesion between the printed ink layer (12) and the printed anchor coat layer (13), it is usually 0.5 to 3 μm, preferably 0.8 to 2 μm.

[0052] <Barrier layer (14)> The barrier layer (14) is a layer for protecting the contents (C) of the package (3) from gas, water vapor, light, etc., and is made of metal foil. Examples of the metal foil include aluminum foil, iron foil, stainless steel foil, copper foil, and nickel foil, and aluminum foil is preferred in terms of barrier function, formability, cost, etc. Examples of the aluminum foil include pure aluminum foil or aluminum alloy foil, and soft materials (O materials) are preferred, and particularly preferred are 1000 series pure aluminum foil O materials, 3000 series aluminum alloy foil O materials, and 8000 series aluminum alloy foil O materials as specified in JIS H4160. A base layer (not shown) made of a predetermined chemical conversion treatment liquid can be formed on the outer surface and / or inner surface of the metal foil. The chemical conversion treatment liquid can be, for example, a water-alcohol solution containing phosphoric acid, a chromium-based compound, a fluorine-based compound and / or a binder resin. The chromium-based compound can be chromic acid and / or a chromium (III) salt, the fluorine-based compound can be a metal salt of fluoride and / or a non-metal salt of fluoride, and the binder resin can be at least one resin selected from the group consisting of an acrylic resin, a chitosan derivative resin and a phenolic resin. The amount of the chemical conversion treatment liquid used is not particularly limited, but the amount of chromium deposited on one side of the metal foil is usually 0.1 to 50 mg / m. 2 It is sufficient if the range is such that The thickness of the barrier layer (14) is not particularly limited, but taking into consideration the strength of the entire cover (2) and the resistance of the printed layer, it is usually 6 to 50 μm, and preferably 10 to 35 μm.

[0053] <Inner surface anchor coat layer (15)> The inner anchor coat layer (15) is an optional layer used for the purpose of adhering the barrier layer (14) to the buffer layer (16) and / or the sealing layer (17) and preventing delamination between the two layers, and can be composed of any of various known anchor coat agents (hereinafter sometimes referred to as inner anchor coat agents) that can perform such functions. Examples of the inner anchor coating agent include epoxy resin-based, chlorinated polyolefin-based, polyamide resin-based, acrylic resin-based, vinyl chloride-vinyl acetate copolymer-based, polyester (unsaturated copolymer polyester, saturated copolymer polyester, etc.)-based, and polyurethane resin-based anchor coating agents, and when the lid (2) is used as a food packaging material, solvent-free agents can be used. Among these, polyurethane resin-based inner anchor coating agents are preferred in terms of print layer resistance, since they have good adhesion to the metal foil, can form a highly flexible inner anchor coating layer (15), and can mitigate external forces applied to the outermost surface of the protective layer (11). As the polyurethane resin anchor coating agent, a two-part curing type polyether-urethane resin adhesive and / or a two-part curing type polyester-urethane resin adhesive are suitable. Both of them are composed of a base agent and a curing agent, and the base agent may be various known polyether polyols and / or polyester polyols. As the curing agent, an isocyanate-based curing agent may be used, and examples of the curing agent include polyisocyanates such as hexamethylene diisocyanate, isophorone diisocyanate, tolylene diisocyanate, and diphenylmethane diisocyanate, as well as their derivatives (isocyanurate, biuret, adduct, etc.). The inner anchor coat layer (15) can be formed by a known printing method such as bar coater printing, gravure printing, offset printing, and flexographic printing, and may be monochromatic, single-coated, or multi-coated. The thickness of the inner anchor coat layer (15) is not particularly limited, but taking into consideration the above-mentioned delamination prevention effect and printed layer resistance, etc., it is usually sufficient if it is about 0.5 μm to 7 μm, and preferably about 0.5 μm to 5 μm.

[0054] <Buffer layer (16)> The lid laminate (1) may have a buffer layer (16) between the inner anchor coat layer (15) and the sealing layer (17). The buffer layer (16) has a function of increasing the printed layer resistance, internal pressure seal resistance, internal pressure crack resistance, etc. of the lid laminate (1) and the lid (2) through its buffering effect. In addition, the provision of the buffer layer (16) improves the tear strength of the lid laminate (1) and the lid (2), thereby ensuring resistance to, for example, puncture by a straw. The buffer layer 16 is preferably made of any of the known polyolefins and may be in the form of a film (oriented or unoriented) or an extruded layer. Examples of polyolefins include homopolypropylene (hPP), ethylene-propylene random copolymer (rPP), ethylene-propylene block copolymer (bPP), and polyethylene (PE). Examples of polyethylene include low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), and high-density polyethylene (HDPE). Among these, polyethylene has the following advantages. First, it has good pressure dispersion properties during heat sealing. Second, it can better relieve external stress that is repeatedly applied to the lid (2) for a long time during transportation of the package (4). Third, it has good relaxation properties for stress that is applied to the barrier layer (14) when the package (4) is opened. From the above, when polyethylene is used as polyolefin, the internal pressure sealability and internal pressure crack resistance of the lid laminate (1) and the lid (2) are improved, and cracks and tears of the metal foil that forms the barrier layer (14) are reduced. The thickness of the buffer layer (16) is not particularly limited, and is usually 10 μm to 50 μm, preferably 20 μm to 35 μm, from the viewpoints of straw puncture resistance, internal pressure sealability, internal pressure crack resistance, heat sealability, and the like.

[0055] <Sealing layer (17)> The sealing layer (17) constitutes the innermost surface of the lid (2) and is a layer for thermally sealing the lid (2) to the opening edge (31) of the container (3), and there are two types as follows. That is, in the first type, as shown in Figures 1(a) and (d), the sealing layer (17) is composed of a single layer made of a thermally adhesive resin. In the second type, as shown in Figures 1(b) and (c), the sealing layer (17) is composed of a base layer (17a) and a sealant layer (17b). Hereinafter, when the term "sealing layer (17)" is used simply, it refers to both the sealing layer (17) of the first embodiment and the sealing layer (17) of the second embodiment, unless otherwise specified.

[0056] The sealing layer (17) in the first embodiment is made of a hot melt adhesive or a heat-sealable resin film. The hot melt adhesive is a composition containing a base resin, a tackifier resin, and optionally a wax, and various known hot melt adhesives can be used. Examples of the base resin include polyolefins and ethylene vinyl acetate copolymers. Examples of the polyolefins include the above-mentioned polyethylene and polypropylene. Examples of the vinyl acetate copolymers include ethylene-vinyl acetate copolymer (EVA) and ethylene-ethyl acrylate-vinyl acetate copolymer. Examples of tackifier resins include rosin, disproportionated rosin, rosin ester, terpene resin, C5 petroleum resin, C9 petroleum resin, C5-C9 petroleum resin, etc. The amount of the tackifier resin used is not particularly limited, and is usually about 10 to 50 parts by weight per 100 parts by weight of the base resin. Examples of waxes include natural waxes, mineral waxes, petroleum waxes, and synthetic waxes. Examples of animal and vegetable waxes include candelilla wax, carnauba wax, rice wax, Japan wax, beeswax, spermaceti, shellac wax, and lanolin wax. Examples of mineral waxes include montan wax, ozokerite, and ceresin. Examples of petroleum waxes include paraffin wax, microcrystalline wax, and petrolatum. Examples of synthetic waxes include polyethylene wax, polypropylene wax, Fischer-Tropsch wax, hydrogenated castor oil and hydrogenated castor oil derivatives, wax obtained by grafting styrene onto a polyethylene-polypropylene copolymer, silicon-based wax (silicone wax), fluorine-based wax and amide-based wax (oleic acid amide, ricinoleic acid amide, erucic acid amide, N,N'-methylenebisstearic acid amide, N,N'-ethylenebisoleic acid amide, stearic acid monomethylol amide, silinoleic acid amide wax, stearic acid ester wax, etc.), and complexes thereof. The sealing layer (17) can be formed from a hot melt adhesive by using a hot applicator or a gravure coater. Examples of heat-sealable resin films include films made of homopolypropylene (hPP), ethylene-propylene random copolymer (rPP), and ethylene-propylene block copolymer (bPP), as well as films made of polyethylene (PE) such as low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), and high-density polyethylene (HDPE), and films made of polyvinyl resins such as polystyrene resins. The heat-sealable resin film may be multilayered, and examples thereof include a multilayer film formed by co-extruding at least two types of the same or different heat-sealable resins, a multilayer film formed by laminating at least two sheets of the same or different heat-sealable resin films, and a multilayer film formed of a heat-sealable resin film and an extruded layer made of a heat-sealable resin.

[0057] The base layer (17a) in the second embodiment is a layer provided for the purposes of ensuring the leveling properties of the sealant layer (17b), thereby assisting the heat sealing properties between the lid (2) and the opening edge (31) of the container (3), and further increasing the strength of the lid (2), and is made of various known synthetic resins. The synthetic resin may be, for example, polyolefin, which may be in the form of a film or an extrusion layer. Examples of polyolefin include homopolypropylene (hPP), ethylene-propylene random copolymer (rPP), and ethylene-propylene block copolymer (bPP), and examples of polyethylene (PE) include low density polyethylene (LDPE), linear low density polyethylene (LLDPE), and high density polyethylene (HDPE), etc. The sealant layer (17b) in the second embodiment can be formed of the heat-sealable resin film constituting the seal layer (17) in the first embodiment. The heat-sealable resin film may be multi-layered as described above, and may take the form of the multi-layer film described above. The seal layer (17) of the second embodiment can be prepared as an independent member (composite film), for example, by co-extruding a synthetic resin forming the base layer (17a) and a heat-fusible resin forming the sealant layer (17b), or by extruding a synthetic resin forming the base layer (17a) onto a film-like sealant layer (17b) that has already been prepared. Examples of extrusion methods include various known methods (sheet extrusion, T-die, inflation, etc.).

[0058] It is preferable that the sealing layer (17) of the first embodiment and the sealant layer (17b) of the second embodiment are both made of a heat-sealable resin film, since this improves the heat sealability (particularly the heat seal strength) of the lid (2) compared to when they are made of a hot melt adhesive.

[0059] In terms of heat sealability, it is preferable that the heat-sealing resin constituting the seal layer (17) of the first embodiment and the sealant layer (17b) of the second embodiment is the same or of the same type as the heat-sealing resin constituting the opening edge portion (31) of the container (3). A specific combination is that the seal layer (17) of the first embodiment or the sealant layer (17b) of the second embodiment is made of a polyvinyl resin (preferably polystyrene), and the heat-sealing resin constituting the opening edge portion (31) is made of a polyvinyl resin (preferably polystyrene).

[0060] In both the first and second embodiments, the overall thickness of the seal layer (17) is usually 5 μm to 50 μm, preferably 25 μm to 35 μm, in consideration of heat sealability. In this regard, when the seal layer (17) is made of a hot melt adhesive, the coating amount is usually 10 to 25 g / m 2 , preferably 12 to 20 g / m 2 It would be good if that were the case.

[0061] From the viewpoint of heat sealability, the seal layer (17) of the second embodiment preferably has a ratio (T17a / T17b) of the thickness (T17a) of the base layer (17a) to the thickness (T17b) of the sealant layer (17b) of usually about 1 / 3 to 3 / 1.

[0062] As shown in Fig. 1(d), a predetermined embossed pattern (18) may be formed over the entire innermost surface of the sealing layer (17). By forming the embossed pattern (18), when the lid (2) is heat-sealed to the opening edge (31) of the container (3), the gas inside the container (3) can be discharged to the outside of the container (3) through the gaps (18b) in the embossed pattern (18), improving the flatness of the lid (2) in the package (4) and the internal pressure-resistant sealing property of the package (4).

[0063] The embossed pattern 18 is made up of a plurality of independent protrusions 18a. The protrusions 18a are scattered at predetermined intervals 18b on a continuous base surface 18c. The shape of the convex portion (18a) is not particularly limited as long as it is an independent unit of protrusion, and may be rhombic, cylindrical or dot-shaped, elliptical, rectangular, conical, trapezoidal, staggered, annular, dome-shaped, etc. For example, the convex portion (18a) in Fig. 1(d) is substantially cylindrical with a flattened top, and is regularly and periodically arranged at regular intervals (18b) on a flat base surface (18c). A specific pattern may also be formed by assembling a plurality of convex portions (18a) of different shapes. The regularity of the arrangement of the protrusions (18a) is not limited, and they may be periodic or irregular. The size of the protrusions (18a) is not limited either. For example, when the protrusions (18a) are substantially cylindrical as shown in FIG. 1(d), the diameter of one unit may be, for example, about 100 μm to 1000 μm. The density of the protrusions (18a) is not particularly limited, and may be, for example, 1 to 130 pieces / cm 2 It's fine as long as it's to a certain extent. The height (H) of the protrusions (18) is not particularly limited, and may be greater than the total thickness (T17) of the seal layer (17) and less than the total thickness (T16+T17) of the buffer layer (16) and the seal layer (17). By doing so, air can be removed more reliably during heat sealing. In this case, both T16 and T17 are the thicknesses before embossing. The size of the intervals (18b) between the protrusions (18a) is not particularly limited, and may be 90 μm to 900 μm, for example, when the protrusions (18a) are substantially cylindrical as shown in FIG. 1(d). The base surface (18c) may be flat or may be a surface having a partially concave shape. In consideration of the flatness, heat sealability, and internal pressure crack resistance of the lid (2), it is preferable that the base surface (18c) is flat. In addition, it is preferable in terms of heat sealability that the area of ​​the base surface (18c) is larger than the total area of ​​the convex portions (18a).

[0064] The lid laminate (1) can be manufactured by various known lamination methods, such as, for example, a dry lamination method, a melt (co)extrusion lamination method, a sandwich lamination method, a heat lamination method, a T-die method, a Comma Coater (registered trademark) method, a Comma Direct (registered trademark) method, etc., and these methods may be combined. As a specific manufacturing example, taking the sandwich lamination method as an example, there can be mentioned a method in which an intermediate member (hereinafter the same applies when referring to the intermediate member) having an overprint coating layer (11), a printed ink layer (12), a printed anchor coating layer (13), a barrier layer (14), and an inner anchor coating layer (15) is provided, and while a buffer layer (16) is extruded onto the innermost surface consisting of the inner anchor coating layer (15), a sealing layer (17) is bonded to it.

[0065] The method of forming the embossed pattern (18) on the bottom surface of the seal layer (17) of the lid laminate (1) is also by various known means. Specifically, for example, a method of pressing a press roll having a predetermined concave pattern (debossed pattern) formed on the surface of the heat-sealable resin film forming the seal layer (17) to form the embossed pattern (18) can be mentioned. In addition, a method of applying the hot melt adhesive forming the seal layer (17) to the surface of the buffer layer (16) using the press roll and simultaneously forming the embossed pattern (18) can be mentioned. When using a hot melt adhesive, it is also good to use the T-die method or the comma coater method, considering that the adhesive becomes highly viscous at high temperatures. The press roll may be a cooling roll or a heating roll. In addition, the press roll can also serve as a coating roller, a transfer roller, and a shaping roller, and for example, a gravure roll can be used.

[0066] From the viewpoint of low odor, the less the residual organic solvent in the lid laminate (1) is, the better, especially when the contents (C) are products that are orally ingested, such as food or beverage. The organic solvent mainly comes from the overprint coat layer (11), the printing ink layer (12), the printing anchor coat layer (13), and optionally the inner anchor coat layer (15). The residual amount of such organic solvent is 5 mg / m or less when measured in accordance with a standard gas chromatography test in accordance with the "Manual for Control Equipment for the Manufacturing of Flexible Packaging Materials" edited by the Flexible Packaging Hygiene Council. 2 Less than 4 mg / m 2 It is better to be less than that.

[0067] The physical properties of the lid laminate (1) are not particularly limited, but for example, if the tear strength measured in accordance with the Elmendorf method specified in JIS K7128-2 is 200 to 1200 mmN, the lid (2) will be less likely to tear when the package (4) is opened, and the lid (2) will also have good resistance to being pierced by a straw.

[0068] <Lid (2), container (3), packaging (4)> The lid (2) is formed by processing the lid laminate (1) into a predetermined shape. The shape of the lid (2) is not particularly limited and can be appropriately determined depending on the shape of the container (3) and the opening method of the package (4).

[0069] Fig. 2(a) is a perspective view of a cap-shaped lid (2). The lid (2) is composed of a substantially horizontal main body portion (2a) and a skirt portion (2b) that extends downward from the periphery of the main body portion (2a).

[0070] 2(b) and (c) are cross-sectional views of the packaging body (4). For example, as shown in Fig. 2(b), when the container (3) is bottle-shaped and the opening edge (31) is rim-shaped, the lid (2) may be cap-shaped. Although not shown, even if the container (3) is bottle-shaped, the opening edge (31) can be formed into a flange shape. Also, for example, as shown in FIG. 2(c), when the container (3) is cup-shaped and the opening edge portion (31) is a substantially horizontal flange-like shape, the lid (2) may be sheet-like, and an opening tab such as a tab or notch may be formed on the lid (2) as necessary.

[0071] The sealing properties of the lid (2) are also not particularly limited. for example, (i) The sealing layer (17) of the lid laminate (1) is heat-sealed to a 0.3 mm thick sheet made of the same heat-sealable resin film as that constituting the layer (16) under conditions of 160° C., 0.2 MPa and 1 second, and then (ii) When the strength when the lid laminate (1) and the sheet are peeled off at a tensile speed of 300 mm / min in a T-peel test in accordance with JIS K6854-3 is 5 to 15 N / 15 mm, (iii) The aforementioned problem of seal retraction or peeling of the seal caused by an increase in internal pressure during transportation of the package (4) does not occur, so that leakage of the contents (C) can be reliably prevented and the ease of opening of the package (4) can be ensured.

[0072] The material of the container (3) is not limited and is selected depending on the heat-sealing property of the opening edge (31) and the lid (2) and the properties of the contents (C). Examples of the material include thermoplastic synthetic resins such as the above-mentioned polyolefin, polyester, and polyvinyl resin, as well as glass, iron, copper, aluminum, etc. If the opening edge (31) of the container (3) is made of the same or similar heat-sealing resin as the heat-sealing resin film forming the bottom surface of the sealing layer (17), the sealing precision and strength of the package (4) will be improved, making it easier to prevent the above-mentioned seal recession, peeling of the seal, and leakage of the contents (C). A specific combination is to select polystyrene as the resin forming the opening edge (31) and a polystyrene film as the heat-sealing resin film forming the sealing layer (17).

[0073] The shape of the container (3) is not particularly limited, and examples of such shapes include a cup shape, a bottle shape, a cylindrical shape, etc. When the container (3) is bottle-shaped, a stable seal can be achieved by tapering the neck portion as shown in Fig. 2(b). The method for producing the container (3) is not particularly limited, and examples thereof include deep drawing, blow molding, vacuum molding, and compressed air molding.

[0074] Examples of the contents (C) include solid or liquid food products such as dairy products, milk drinks, lactic acid bacteria drinks, soft drinks, ham, cheese, curry, sauce, etc., or liquid or solid pharmaceutical products, chemical products, etc.

[0075] The package (4) is formed by overlapping the lid (2) from the sealing layer (17) side on the opening edge (31) of the container (3) containing the contents (C) and sealing the lid (2) by heat sealing using various known sealing devices. The sealing conditions are not particularly limited and are appropriately determined depending on the material of the lid (2) and the container (3) and the specifications of the sealing device. The sealing means is also not particularly limited and may be appropriately selected from heat sealing, high-frequency sealing, ultrasonic sealing, etc., but the high-frequency sealing method (high-frequency induction heating by a high-frequency sealing device) is preferable in terms of productivity because it enables high-speed sealing. The high-frequency sealing method is particularly preferable when the bottom surface of the sealing layer (17) of the lid (2) is made of a heat-sealable resin film, and is even more preferable when the film has an embossed pattern.

[0076] The opening strength of the package (4) is not particularly limited, but considering both sealing and easy opening, it is preferable that the strength when the lid (2) heat-sealed to the opening edge (31) of the container (3) is peeled from the opening edge (31) at a tensile speed of 300 mm / min in a T-peel test conforming to JIS K6854-3 is 5 to 15 N / 15 mm. In this case, the seal recession and peeling of the seal due to the increase in internal pressure during transportation of the package (4) do not occur, and leakage of the contents (C) can be reliably prevented and the package (4) can be easily opened. Note that this opening strength is based on the premise that the material of the seal layer (17) of the lid (2) and the material of the opening edge (31) of the container (3) are the same or the same type of synthetic resin.

[0077] The package (4) is, for example, stored in an outer box and then refrigerated. At this time, condensation may occur on the surface of the package (4). However, as already described, the lid laminate (1) forming the lid (2) of this package (4) has a predetermined layer structure. Even if the condensed water penetrates into the overprint coat layer (11) and reaches the printed ink layer (12), the printed ink layer (12) is bonded to the barrier layer (14) via the printed anchor coat layer (13) and does not peel off or fall off from the barrier layer (14). Therefore, even if some external force is applied to the surface of the package (4) when it is transported or packed after refrigerated storage, it is considered that defects such as scratches, shifting, or falling off of the printed surface will not occur. EXAMPLES

[0078] The present invention will be described in more detail below through examples and comparative examples, but the scope of the present invention is not limited to these specific examples.

[0079] <Preparation of Laminated Material for Lid (1)> Example 1 The outer surface anchor coating agent PE1 was applied to one side of a 25 μm thick aluminum foil (A8079H-O) constituting the barrier layer (14) with a roll coater so that the thickness after drying would be approximately 1.0 μm, and then dried at 70° C. for 30 seconds to form a printed anchor coating layer (13). This outer surface anchor coating agent PE1 was a methyl ethyl ketone (MEK) solution of aromatic polyester, and the aromatic polyester, which was the main component, contained residues derived from isophthalic acid, neopentyl glycol, and ethylene glycol. Next, white printing ink (pigment: titanium dioxide, binder resin: vinyl chloride-vinyl acetate copolymer (VCVA); hereinafter the same) was applied onto the printed anchor coat layer (13) using a roll coater so that the thickness after drying would be approximately 2.0 μm, thereby forming a printed ink layer (12). Next, a solution of nitrocellulose (NC) in ethyl acetate was applied onto the printing ink layer (12) using a roll coater so that the thickness after drying would be approximately 1.0 μm, and then dried at 80° C. for 1 minute to form an overprint coating layer (11), thereby producing an intermediate member. Next, a two-component curing polyester-urethane resin adhesive (hereinafter also referred to as two-component PU) was applied to the other surface of the aluminum foil (barrier layer (14)) of the intermediate member using a roll coater so that the thickness after drying would be 1.0 μm, and the adhesive was dried at 100° C. for 1 minute to form an inner anchor coat layer (15). Next, as a film for forming the sealing layer (17), a polystyrene composite film consisting of a 7.0 μm-thick low-density polyethylene (LDPE) layer and a 23 μm-thick polystyrene (PS) layer was produced by coextrusion. Next, molten low-density polyethylene (LDPE) was extruded through a T-die onto the inner anchor coat layer (16) of the intermediate member to form a buffer layer (16) having a thickness of 35 μm, while the polystyrene composite film forming the sealing layer (17) was sandwich-laminated from the low-density polyethylene (LDPE) layer side through a cooling roll to produce the lid laminate A.

[0080] Example 2 A lid laminate B was prepared in the same manner as in Example 1, except that a solution of cellulose acetate (CA) was used as the overprint coating agent.

[0081] Example 3 A lid laminate C was prepared in the same manner as in Example 1, except that a commercially available urethane resin (PU)-based overcoat agent was used as the overprint coat agent.

[0082] Example 4 A lid laminate D was produced in the same manner as in Example 1, except that a commercially available epoxy resin (Epoxy)-based overcoat agent was used for the overprint coat layer.

[0083] Example 5 A lid laminate E was produced in the same manner as in Example 2, except that the printed anchor coat layer (13) was composed of the outer anchor coat agent PE2. This outer anchor coat agent PE2 was a methyl ethyl ketone (MEK) solution of aromatic polyester, and the aromatic polyester, which was the main component, contained isophthalic acid-derived residues and ethylene glycol-derived residues, but did not contain neopentyl glycol-derived residues.

[0084] Example 6 A lid laminate F was produced in the same manner as in Example 2, except that the printed anchor coat layer (13) was composed of the outer surface anchor coat agent PE3. This outer surface anchor coat agent PE3 is a methyl ethyl ketone (MEK) solution of aromatic polyester, and the aromatic polyester as the main component contains terephthalic acid-derived residues, neopentyl glycol-derived residues, and ethylene glycol-derived residues, but does not contain isophthalic acid-derived residues.

[0085] Comparative Example 1 In Example 2, a lid laminate G was prepared in the same manner except that a normal propyl acetate-isopropyl alcohol solution containing vinyl chloride-vinyl acetate copolymer (hereinafter abbreviated as VCVA) as the main agent was used as the outer anchor coating agent constituting the printed anchor coating layer (13).

[0086] Comparative Example 2 A lid laminate material H was produced in the same manner as in Example 2, except that the printed anchor coat layer (13) was omitted.

[0087] Table 1 shows the layer structures of the lid laminate materials A to H.

[0088] [Table 1]

[0089] <Evaluation of the durability of the printed layer of the lid laminate (1): 1. Underwater kneading test> Three test pieces measuring 10 cm square were cut out from the lid laminate A, and one of them was placed in the center of the palm of one hand. At this time, the overprint coat layer was placed on the top surface. Then, the palm of the other hand was placed over the test piece, and the test piece was submerged in 24°C water while being held between both hands. Next, in the water, the test piece was firmly gripped once as if rolling it on the inner side of the palm of one hand, and after strongly deforming it, the fist was removed from the water. Next, the fingers were opened, and the wet test piece was spread out to smooth out the wrinkles. Then, the presence or absence of peeling of the printed ink layer was visually observed mainly in the wrinkled parts. The above evaluation was also performed on the remaining two test pieces. The same test was also performed on the lid laminates B to H. The evaluation in this test was carried out according to the following criteria.

[0090] ◎: Ratio of (number of test pieces where the printed ink layer did not peel off / number of test pieces immersed) = 3 / 3 ○: Same ratio = 2 / 3 △: Same ratio = 1 / 3 ×:Same ratio=0 / 3

[0091] The evaluation results of the resistance of the printed layer in the underwater crumpling test are shown in Table 1.

[0092] <Evaluation of the durability of the printed layer of the lid laminate (1): 2. Friction test> This test is carried out using a sliding test device (5) as shown in Fig. 3. This device is composed of at least a stainless steel support (51), a stainless steel spherical member (52) (diameter 10 mm) connected to the tip of the support (51), and a stainless steel support base (53). The surface of the spherical member (52) is covered with cotton gauze (not shown). In this test, first, two 10 cm square test pieces are prepared from the lid laminate A. Next, one of the test pieces is placed on a support stand (53) and the four sides are fixed with adhesive tape. Next, 0.5 cc of water is dropped onto the surface of the overprint coat layer, and then the support (51) is lowered to lightly press the spherical member (52). In this state, the support (51) is moved back and forth in the left and right direction at a reciprocating distance of 2 cm / sec, and the number of reciprocations is counted at the point when a change in appearance occurs, such as the occurrence of fading on the printed surface. However, the upper limit is 30 times. The same test was conducted for the lid laminate B to H. The resistance of the printed layer to frictional force was evaluated according to the following criteria.

[0093] ◎: No change in appearance occurs on the printed surface even after 28 or more reciprocal passes. ◯: Appearance change occurs on the printed surface after 25 to 27 back and forth passes. △: Appearance change occurs on the printed surface after 22 to 24 strokes. ×: Appearance change occurs on the printed surface after 23 or fewer reciprocations.

[0094] The evaluation results of the resistance of the printed layer in the above-mentioned friction test are shown in Table 1.

[0095] <Making the lid (2)> Lid A was produced by cutting out a small circular piece having a diameter of 90 mm from lid laminate material A. Lid laminate materials B to H were used in the same manner to produce lids B to H of the same dimensions.

[0096] <Preparation of packaging body (4)> A cup-shaped polystyrene container (3) (height 26 mm, opening diameter 66 mm, flange width 7 mm) having a flange (31) around the opening edge was prepared. Then, 54 cc of water was poured into the container (3) as the content (C), and then the lid A was placed on the top of the flange (31) from the sealing layer (17) side, and a stainless steel plate heated to 150°C was pressed against the lid A from above for 1.0 second to produce a sealed package A. Packages B to H were produced in the same manner for the lids B to H.

[0097] <Evaluation of the durability of the printed layer of the lid (2) in the package (4)> The test is carried out using a shaking device (6) shown diagrammatically in FIG. First, two packages A were placed on a horizontal table, and with the flanges (31) of the packages abutting against each other, they were bound together by wrapping polyethylene binding film (63) around the sides to prepare a set of samples (62). Eleven more sets of samples (62) were prepared in the same manner. Next, three sets of samples (62) were arranged on the bottom of a packaging material (61) (11 cm long x 24 cm wide x 19 cm deep) made of a cardboard box, and a 1 mm thick cardboard sheet (24 cm x 19 cm) was placed on top of them as a partition material (64), and three more sets of samples (62) were arranged on top of that. This process was repeated two more times, resulting in a total of 12 sets of samples (62) being stacked. Next, this packaging material (61) was wrapped with adhesive tape, and then shaken for 100 hours under specified conditions (120 rpm, amplitude 50 mm) in a commercially available shaking device (SA31, manufactured by Yamato Scientific Co., Ltd.) In Fig. 4, arrow (D1) indicates the direction in which the lid (2) deforms outward, and arrow (D2) indicates the direction in which the lid (2) deforms inward. Next, the packaging material (61) was opened, and the top surface of the lid A of each of the 24 packages A was visually observed to check for peeling of the printed ink layer (12). The same test was also carried out on packages B to H. The printed layer resistance of the lids AH of the packages AH was evaluated according to the following criteria.

[0098] There were 0 to 2 small peelings: Good (○) There were 3 to 10 small peelings: Fairly good (△) 11 to 24 small peels or 1 or more large peels: Poor (×)

[0099] The evaluation results of the print layer resistance by the above test are shown in Table 1.

[0100] The printed layer resistance in this test is a direct evaluation that assumes the friction that occurs on the printed ink layer (12) of the lids A to H on the packages A to H and the impact that is applied to the printed ink layer (12) when the packages A to H are transported, and is in line with the actual situation. [Industrial Applicability]

[0101] The lid laminate of the present invention can be suitably used as a lid for sealing the opening of a container containing liquid or solid foods such as dairy products, milk drinks, lactic acid bacteria drinks, soft drinks, ham, cheese, curry, sauce, etc., or liquid or solid pharmaceuticals, chemicals, etc. [Explanation of symbols]

[0102] (1): Laminated material for lid (11): Overprint coat layer (surface protective layer) (12): Printing ink layer (13): Printed anchor coat layer (14): Barrier layer (15): Inner anchor coat layer (16):Buffer layer (17): Sealing layer (2): Lid (2a): Main body (2b): Skirt part (3): Container (31): Opening edge (flange) (4):Packaging (C):Contents

Claims

1. A laminated material for forming a lid that is heat-sealed to the opening edge of a container holding its contents, From the outside in, it comprises at least a surface protection layer made of an overprint coating agent, a printing ink layer, a printing anchor coating layer made of an anchor coating agent, a barrier layer made of metal foil, and a sealing layer made of a heat-sealable resin. A laminated material for lids, characterized in that the anchor coating agent comprises a composition based on aromatic polyester.

2. The laminated lid material according to claim 1, characterized in that the aromatic polyester has at least one of a residue derived from an aromatic dicarboxylic acid and a residue derived from an aliphatic diol.

3. The laminated lid material according to claim 2, characterized in that the aromatic dicarboxylic acid residue includes a residue derived from isophthalic acid.

4. The laminated lid material according to claim 2, characterized in that the aliphatic diol residue includes a residue derived from a branched aliphatic diol having a total of 5 to 10 carbon atoms and a residue derived from a linear aliphatic diol having a total of 1 to 5 carbon atoms.

5. The aforementioned aromatic polyester has residues derived from aromatic dicarboxylic acids and residues derived from aliphatic diols. The aforementioned aromatic dicarboxylic acid residue includes a residue derived from isophthalic acid, The laminated lid material according to claim 1, characterized in that the aliphatic diol residue includes a residue derived from a branched aliphatic diol having a total of 5 to 10 carbon atoms and a residue derived from a linear aliphatic diol having a total of 1 to 5 carbon atoms.

6. The overprint coating agent consists of at least one selected from the group consisting of cellulose-based overprint coating agents, synthetic resin-based overprint coating agents, and natural product-based overprint coating agents. The cellulose-based overprint coating agent contains at least one of nitrocellulose, cellulose acetate, cellulose propionate, and cellulose acetate / butyrate as a binder resin. The aforementioned synthetic resin-based overprint coating agent contains at least one of the following as a binder resin: epoxy resin, polyurethane resin, chlorinated polyolefin resin, acrylic resin, vinyl chloride-vinyl acetate copolymer, and polyester. The lid laminate material according to claim 1, characterized in that the natural product-based overprint coating agent contains shellac resin as a binder resin.

7. The laminate for a lid according to claim 1, characterized in that the printing ink layer contains an active energy ray non-curing binder resin comprising at least one of the following: shellac resin, nitrocellulose, cellulose acetate, cellulose propionate, cellulose acetate / butyrate, epoxy resin, polyurethane resin, chlorinated polyolefin resin, polyamide resin, acrylic resin, vinyl chloride-vinyl acetate copolymer, and polyester.

8. A lid that is heat-sealed to the opening edge of a container holding contents, characterized in that it is formed from any one of the lid laminates specified in claims 1 to 7.

9. A packaging body characterized in that the lid described in claim 8 is heat-sealed to the opening edge of a container containing its contents.

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