Laminate material for lid, lid, package

Abstract

To provide a laminate material for a lid in which a protective layer, a printing layer, a barrier layer made of a metal foil, and a heat seal layer made of a thermoplastic resin are laminated in order from the outside and which does not cause problems such as peeling, drop-off and displacement or the like of the printing layer even if some external force is applied to the protective layer or strong friction occurs on a surface of the protective layer.SOLUTION: A laminate material 1 for a lid is provided with an undercoat layer 13 between a printing layer 12 and a barrier layer 14, and a protective layer 11, the printing layer 12 and the undercoat layer 13 are each composed of a composition containing a thermoplastic resin and an organic solvent, in addition, a glass transition temperature of the thermoplastic resin forming the protective layer 11 is made higher than a glass transition temperature of the thermoplastic resin forming the printing layer 12, and is made higher than a glass transition temperature of the thermoplastic resin forming the undercoat layer 13 .SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a laminated material for lids, a lid made of the laminated material, and a packaging body formed by heat-sealing a container containing contents with the lid. Examples of contents include orally ingestible products such as liquid or solid food products or pharmaceuticals. [Background technology]

[0002] Traditionally, food products and pharmaceuticals were placed in molded containers made of synthetic resin, metal, paper, etc., and the opening of the molded container was heat-sealed with a heat-sealable lid. These sealed packages were then distributed to the market and displayed in stores.

[0003] The aforementioned lid may be made from various metal laminate packaging materials for the purpose of protecting the contents from light, gas, moisture, etc. This metal laminate packaging material is a laminated material in which a barrier layer made of metal foil is interposed in the middle of the thickness, and the innermost heat-seal layer is formed of a heat-sealable resin film or hot-melt adhesive.

[0004] The aforementioned lid may have a printed layer made of printing ink on the outside of the barrier layer for the purpose of displaying information such as the product name and ingredients of the contents, or displaying barcodes, designs, etc. On the surface of the printed layer, a synthetic resin film such as polyethylene terephthalate may be laminated as a protective layer to retain the printed information, or an overprint coat layer made of various coating agents may be formed as shown in Patent Documents 1 to 3. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2014-31016 [Patent Document 2] Japanese Patent Publication No. 2014-62234 [Patent Document 3] Japanese Patent Publication No. 2019-206387 [Overview of the project] [Problems that the invention aims to solve]

[0006] Incidentally, while packaging is transported from the factory to the warehouse, then to the retailer, and finally to the consumer, vibrations during transport or handling, or mishandling, can cause friction or impact when an object comes into contact with the surface of the lid. In such cases, the printing layer may peel off along with the protective layer, detach from the barrier layer, or become misaligned on the printed surface due to the action of such external forces. Such problems are particularly likely to occur around the periphery, such as the edges of the main body or skirt, when the lid is a cap-like shape, as shown in Figure 3(a). [Means for solving the problem]

[0007] In view of the above problems, the inventors have set as their primary objective to provide a laminated lid material having a protective layer, a printed layer, a barrier layer made of metal foil, and a heat-seal layer made of thermoplastic resin laminated in that order from the outside, and which has the property (hereinafter sometimes referred to as "printed layer resistance") such that the printed layer does not peel off, fall off, or shift even when some external force is applied to the surface of the protective layer or strong friction occurs. Furthermore, as a further objective, the inventors have set as providing a lid made of such a laminated lid material and a packaging body in which the lid is an element.

[0008] As a result of further investigation, the inventors have found that by (i) providing an undercoat layer (anchor coat layer) between the printing layer and the barrier layer in a lid laminate material in which a protective layer, a printed layer, a barrier layer made of metal foil, and a heat-seal layer made of thermoplastic resin are laminated in order from the outside, (ii) the protective layer, the printed layer, and the undercoat layer are each composed of a composition containing a thermoplastic resin and an organic solvent, and (iii) the glass transition temperature of the thermoplastic resin forming the protective layer is made higher than the glass transition temperature of the thermoplastic resin forming the printing layer, and at the same time higher than the glass transition temperature of the thermoplastic resin forming the undercoat layer, the inventors have found that a lid laminate material, a lid, and a packaging body that can solve the above problems can be obtained, and the present invention has been completed.

[0009] In other words, the present invention relates to a laminated material for lids as shown in 1) to 14) below, a lid obtained from the laminated material, and a packaging body having the lid as an element.

[0010] 1) A laminated lid material for making a lid that is heat-sealed to the periphery of an opening so as to cover the opening of a container containing contents, comprising, in order from the outside, a protective layer made of an overcoat agent containing a thermoplastic resin and an organic solvent, a printing layer made of a printing ink containing a thermoplastic resin, an organic solvent and a colorant, an undercoat layer made of an anchor coat agent containing a thermoplastic resin and an organic solvent, a barrier layer made of metal foil, and a heat-seal layer made of a heat-sealable resin, characterized in that the glass transition temperature of the thermoplastic resin making up the printing layer and the glass transition temperature of the thermoplastic resin making up the undercoat layer are both lower than the glass transition temperature of the thermoplastic resin making up the protective layer.

[0011] 2) The laminated lid material according to 1), characterized in that the glass transition temperature of the thermoplastic resin forming the protective layer is 100°C or higher, the glass transition temperature of the thermoplastic resin forming the printing layer is less than 100°C, and the glass transition temperature of the thermoplastic resin forming the undercoat layer is less than 100°C.

[0012] 3) The lid laminate according to 1) or 2), wherein the melting points of the thermoplastic resins forming the printing layer and the undercoat layer are both lower than the melting point of the thermoplastic resin forming the protective layer.

[0013] 4) The lid laminate according to any one of 1) to 3), wherein the melting point of the thermoplastic resin forming the protective layer is 130°C or higher, the melting point of the thermoplastic resin forming the printing layer is lower than 130°C, and the melting point of the thermoplastic resin forming the undercoat layer is lower than 130°C.

[0014] 5) The lid laminate according to any one of 1) to 4), wherein when the total thickness of the protective layer, the printing layer, and the undercoat layer is 1, the thickness ratio of the protective layer is 34% to 85%, the thickness ratio of the printing layer is 7% to 33%, and the thickness ratio of the undercoat layer is 8% to 33%.

[0015] 6) The lid laminate according to any one of 1) to 5), wherein the thermoplastic resin forming the printing layer and the thermoplastic resin forming the undercoat layer are the same or of the same type.

[0016] 7) The lid laminate according to any one of 1) to 6), wherein the thermoplastic resin forming the protective layer is a cellulose-based thermoplastic resin, the thermoplastic resin forming the printing layer is a synthetic resin-based thermoplastic resin, and the thermoplastic resin forming the undercoat layer is a synthetic resin-based thermoplastic resin.

[0017] 8) The lid laminate according to any one of 1) to 7), wherein an inner undercoat layer made of an anchor coating agent and / or a buffer layer made of a synthetic resin is interposed between the barrier layer and the heat seal layer.

[0018] 9) The lid laminate according to any one of 1) to 8), wherein the heat seal layer is made of a hot melt adhesive.

[0019] 10) The lid laminate according to any one of 1) to 8), wherein the heat seal layer is composed of a base material layer made of a synthetic resin and a heat seal layer made of a heat-fusible resin film in that order from the outside.

[0020] 11) A lid laminate according to any of 1 to 10), characterized in that an embossed pattern consisting of multiple independent protrusions is formed over the entire innermost surface of the heat seal layer.

[0021] 12) The measured amount of residual organic solvent using the gas chromatography standard test method, in accordance with the manual for control equipment related to the manufacture of flexible packaging materials, edited by the Flexible Packaging Hygiene Council, was 5 mg / m³. 2 A laminated lid material characterized by being less than any of 1) to 11).

[0022] A lid characterized by being made of any of the lid laminate materials described in 13)1) to 12).

[0023] 14) A packaging body characterized by being obtained by heat-sealing the lid of 13) to the periphery of the opening of a container containing its contents, so as to cover the opening. [Effects of the Invention]

[0024] The laminated lid material described in 1) is characterized in that the glass transition temperature of the thermoplastic resin forming the protective layer is higher than both the glass transition temperature of the thermoplastic resin forming the printed layer and the glass transition temperature of the thermoplastic resin forming the undercoat layer. In other words, the protective layer is relatively harder than the printed layer and the undercoat layer. Therefore, even if an external force is applied, such as when an object comes into contact with the outermost surface of the protective layer and strong friction occurs, or when some kind of impact is applied, the protective layer itself will not suffer coating defects such as peeling or detachment. Furthermore, although the external force acting on the protective layer is transmitted to the printed layer and then to the undercoat layer inside it, the printed layer and the undercoat layer are relatively softer than the protective layer, so the external force is mitigated in both layers. In addition, since the undercoat layer does not contain printing ink like the printed layer, it has excellent adhesion to the metal foil that constitutes the barrier layer. Due to the effects described above, the laminated material for lids of the present invention is less prone to problems such as peeling, detachment, and misalignment of the printed layer, and is therefore considered to exhibit excellent print layer resistance.

[0025] The laminated lid material in 2) has better print layer resistance than the laminated lid material in 1), because the glass transition temperature of the thermoplastic resin forming the protective layer is set to 100°C or higher, and the glass transition temperatures of both the thermoplastic resin forming the printing layer and the thermoplastic resin forming the undercoat layer are set to less than 100°C.

[0026] 3) The laminated lid material is characterized in that the melting point of the thermoplastic resin forming the protective layer is higher than both the melting point of the thermoplastic resin forming the printed layer and the melting point of the thermoplastic resin forming the undercoat layer. In other words, the protective layer is relatively harder than the printed layer and the undercoat layer. Therefore, even if an external force is applied, such as when some object comes into contact with the outermost surface of the protective layer and strong friction occurs, or when some kind of impact is applied, the protective layer itself will not suffer coating defects such as peeling or detachment. Furthermore, the external force acting on the protective layer is transmitted to the printed layer inside it, and then to the undercoat layer, but since the printed layer and the undercoat layer are relatively softer than the protective layer, such external forces are mitigated in both layers. Due to the above effects, the laminated lid material of the present invention is less prone to problems such as peeling, detachment, and displacement of the printed layer, and therefore exhibits excellent print layer resistance.

[0027] The laminated lid material in 4) is one of the laminated lid materials in 1) to 3), but the melting point of the thermoplastic resin forming the protective layer is set to be 130°C or higher, and the melting points of both the thermoplastic resin forming the printing layer and the thermoplastic resin forming the undercoat layer are set to be below 130°C, thus providing better resistance to the printing layer.

[0028] The laminated lid material in 5) is one of the laminated lid materials in 1) to 4), and has better print layer resistance because the thickness ratio of the protective layer, printed layer, and undercoat layer is limited to a predetermined range.

[0029] The laminated lid material in 6) is one of the laminated lid materials in 1) to 5), in which both the printed layer and the undercoat layer are made of the same or the same type of thermoplastic resin, and the adhesion between the two layers is enhanced, resulting in even better resistance of the printed layer. Furthermore, because of the high adhesion between the two layers, when a lid made of the laminated material is heat-sealed to the periphery of the container opening, the protective layer of the outermost layer of the lid does not adhere to the sealing plate, preventing the container from lifting and thus avoiding sealing defects and line troubles. This also results in excellent heat seal accuracy and heat seal strength (hereinafter, this effect will be abbreviated as heat sealability), and prevents the printed layer from peeling off due to external forces when the lid is lifted.

[0030] The laminated lid material of 7) is one of the laminated lid materials of 1) to 6), and the thermoplastic resin forming the protective layer is a cellulose-based resin such as nitrocellulose, so the strength and scratch resistance of the protective layer are good, and the water resistance is particularly excellent. On the other hand, both the thermoplastic resin forming the printing layer and the thermoplastic resin forming the undercoat layer are synthetic resins such as polyester resin or vinyl chloride-vinyl acetate copolymer, and the adhesion between the two layers is enhanced. Therefore, the laminated lid material of 7) has good resistance to the printing layer even when placed in a high humidity environment or when water comes into contact with the protective layer.

[0031] The laminated lid material of 8) is characterized in that an inner undercoat layer made of an anchor coating agent and / or a buffer layer made of synthetic resin are interposed on the underside of the barrier layer of any of the laminated lid materials of 1) to 7). When the inner undercoat layer is provided, the adhesion between the barrier layer and the heat seal layer is enhanced, and when the buffer layer is provided, even if the external force acts on the surface of the protective layer, that force is mitigated in the buffer layer. Therefore, since the laminated lid material of 8) is provided with either or both of the inner undercoat layer and the buffer layer, the resistance of the printed layer is improved. In particular, when the buffer layer is provided, the lid made of the laminated lid material of 8) has improved tear strength, so that, for example, resistance to straw punctures can be ensured.

[0032] The laminated lid material in 9) is one of the laminated lid materials in 1) to 8), and its heat-seal layer is formed with hot-melt adhesive, resulting in good print layer resistance and heat-sealability.

[0033] The laminated lid material of 10) is one of the laminated lid materials of 1) to 8), and its heat-seal layer is composed of two independent layers, from the outside in, a base layer made of synthetic resin and a heat-seal layer made of heat-fusible resin film. Therefore, it has good print layer resistance and heat sealability, as well as the internal pressure crack resistance described below. In other words, when a package made of a general metal laminate lid is heat-sealed, and many packages are packed together, there is a risk that fine cracks or fractures will occur in the metal foil that forms the barrier layer of the lid. The reason for this is not clear, but when such bundled packages are exposed to vibrations for a long time during transport, they collide with each other and compress each other, especially during lateral shaking. At this time, the internal pressure of each package increases and decreases, and the lid repeatedly expands and contracts. As a result, repeated stress is continuously applied to the lid, causing the metal foil that forms the barrier layer to undergo cycle fatigue. As a result, it is thought that fine cracks or fractures will occur in the metal foil. In this regard, as described above, the laminated material for the lid in 10) has a heat-seal layer composed of a base material layer and a heat-sealable resin film layer, so such cracks and breaks do not occur in the lid made of this laminated material (hereinafter, this effect will be referred to as internal pressure crack resistance).

[0034] The laminated lid material of 11) is one of the laminated lid materials of 1) to 10), characterized in that an embossed pattern consisting of multiple independent protrusions is formed over the entire innermost surface of the heat-seal layer. Based on this characteristic, a lid made of this laminated lid material exhibits the flatness and internal pressure resistance described below. That is, when a container containing contents is heat-sealed with a lid made of this laminated lid material, gas in the non-contained part of the container is released to the outside of the container through the gaps formed by the spacing of the embossed pattern, resulting in the flatness of the lid being maintained in the heat-sealed package. Furthermore, if the contents of a package made of the laminated lid material described in 11) are, for example, fermented foods such as lactic acid bacteria beverages or articles containing alcohol, the internal pressure of the package will gradually increase depending on the environment in which it is used. However, because the lid has good flatness, internal delamination will not occur from the inside of the opening periphery of the container due to so-called seal settling, nor will it tear (hereinafter, this effect will be referred to as internal pressure resistance to sealing).

[0035] The laminated lid material in 12) is any of the laminated lid materials in 1) to 11), and the residual amount of organic solvent measured by the prescribed procedure is 5 mg / m². 2 Because it is limited to less than a certain level, the odor is very low (hereinafter sometimes referred to as low odor), which is particularly desirable from a hygienic standpoint when the contents are food products.

[0036] The lid of 13) is made of one of the lid laminates of 1) to 12), and in the packaging body, depending on which lid laminate it is made of, it exhibits the same effects as the said laminate (printing layer resistance, heat sealability, straw puncture resistance, internal pressure sealing resistance, internal pressure crack resistance, low odor, etc.).

[0037] The packaging in 14) is a sealed container in which the contents are heat-sealed with the lid in 13), and the lid provides the same effects as any of the laminated lid materials in 1) to 12) (printing layer resistance, heat sealability, straw puncture resistance, internal pressure sealing resistance, internal pressure crack resistance, low odor, etc.). [Brief explanation of the drawing]

[0038] [Figure 1] This is a vertical cross-section of laminated material for lids (with and without embossed pattern). [Figure 2] These are plan and perspective views of the embossed pattern. [Figure 3] This is a perspective view of the lid and a cross-sectional view of the packaging. [Figure 4] This is a schematic diagram of an evaluation apparatus for the print layer resistance of laminated lid material. [Figure 5]This diagram shows a schematic representation of an evaluation apparatus for the print layer resistance of a lid on a packaging body, and a schematic representation of an evaluation apparatus for the internal pressure crack resistance of the same lid. [Modes for carrying out the invention]

[0039] The present invention will be described in detail below with reference to Figures 1 to 5. However, the scope of the invention is not limited by these drawings.

[0040] The lid laminate (1) of the present invention has at least a protective layer (11), a printed layer (12), a primer layer (13), a barrier layer (14), and a heat seal layer (17) in order from the outside. The lid laminate (1) is processed into a predetermined shape to form the lid (2) of the present invention, and the packaging (4) of the present invention is formed by heat sealing a container (3) containing contents (C) with this lid (2).

[0041] Figure 1 shows a vertical cross-section of the laminated lid material (1) of the present invention. The laminated lid material (1) in Figure 1(a) is a composite material in which a protective layer (11), a printed layer (12), a primer layer (13), a barrier layer (14), an inner primer layer (15), a buffer layer (16), and a heat seal layer (17) are laminated in order from the outside. In this composite material, the printed layer (12) is made into an intermittent layer, and the protective layer (11) and the primer layer (13) are partially adhered to each other. The inner primer layer (15) and the buffer layer (16) can be omitted, either individually or in whole. The laminated lid material (1) in Figure 1(b) is a modified version of the laminated lid material (1) in Figure 1(a), in which the printed layer (12) is a continuous layer, and the heat-seal layer (17) is composed of two layers: a base layer (17a) and a heat-seal layer (17b). The laminated lid material (1) in Figure 1(c) is a configuration of the laminated lid material (1) in Figure 1(b) in which both the inner undercoat layer (15) and the buffer layer (16) are omitted. Figures 1(d), 1(e), and 1(f) are cross-sectional views of the laminated lid material (1) in Figure 1(c), in which an embossed pattern (18) is formed on the innermost surface of the heat seal layer (17).

[0042] Figure 2 shows the embossed pattern of the lid laminate (1). Figures 2(a), 2(b), and 2(c) are plan views of the embossed pattern (18), and Figure 2(d) is a perspective view corresponding to the embossed pattern in Figure 2(b). Further details will be described later.

[0043] Figure 3 shows the lid (2) and packaging (4) of the present invention. The lid (2) in Figure 3(a) is cap-shaped and consists of a substantially horizontal circular body (2a) and a skirt (2b) that hangs down from the periphery of the body (2a). In the packaging (4) in Figure 3(b), the lid (2) is cap-shaped, and the container (3) containing the contents (C) is bottle-shaped. The opening periphery (31) of the container (3) is composed of a circular, upright rim with a significant width. In the packaging (4) in Figure 3(c), the lid (2) is sheet-shaped, and the container (3) containing the contents (C) is cup-shaped. The opening periphery (31) of the container (3) is composed of a circular, horizontal flange with a significant width.

[0044] Figure 5 is a conceptual diagram of an evaluation device for the lid (2) of the packaging (4), where Figure 5(a) evaluates the print layer resistance and Figure 5(b) evaluates the resistance to internal pressure cracking. In each figure, the direction of the upward arrow (D1) corresponds to the "outside," which is the direction of the protective layer (11) of the lid (2), which is made of the lid laminate (1). The direction of the downward arrow (D2) corresponds to the "inside," which is the heat seal layer (17) side of the lid (2), and the side facing the opening edge (31) of the container (3).

[0045] <Laminated material for lid (1)> In this specification, "glass transition temperature" refers to the measured value in accordance with JIS K7121:2012, and "melting point" refers to the measured value in accordance with JIS K0064:1992.

[0046] <Thermophysical relationship between the protective layer (11), the printed layer (12), and the undercoat layer (13)> In the present invention, the laminated lid material (1) has a glass transition temperature Tg(12)(°C) lower than that of the thermoplastic resin constituting the printing layer (12), and the glass transition temperature Tg(13)(°C) of the thermoplastic resin constituting the undercoat layer (13), from the viewpoint of resistance to the printed layer. That is, Tg(11)(°C) > Tg(12)(°C) and Tg(11)(°C) > Tg(13)(°C) hold true. In this relationship, the protective layer (11) is made relatively harder than the printing layer (12) and the undercoat layer (13). Therefore, even if some external force is applied to the outermost surface of the protective layer (11), coating defects such as detachment or peeling are unlikely to occur in the protective layer (11) itself. Furthermore, such external forces are transmitted to the printed layer (12) and then to the undercoat layer (13), but because both layers are relatively soft, the force is mitigated in both layers. As a result, it is thought that defects such as peeling, detachment, and misalignment will not occur in the printed layer (12). To further improve the durability of the printed layer, it is preferable that Tg(11)(°C) is 100°C or higher, Tg(12)(°C) is less than 100°C, and Tg(13)(°C) is also less than 100°C. More preferably, Tg(11)(°C) is 120°C to 180°C, Tg(12)(°C) is -30°C to 80°C, and Tg(13)(°C) is -30°C to 80°C.

[0047] In the lid laminate (1) of the present invention, from the viewpoint of print layer resistance, it is preferable that the melting point Tm(12)(°C) of the thermoplastic resin constituting the print layer (12) is lower than the melting point Tm(11)(°C) of the thermoplastic resin constituting the protective layer (11), and that the melting point Tm(13)(°C) of the thermoplastic resin constituting the undercoat layer (13) is also lower. That is, the relationship Tm(11)(°C) > Tm(12)(°C) and Tm(11)(°C) > Tm(13)(°C) holds. In this relationship, the protective layer (11) is made relatively harder than the print layer (12) and the undercoat layer (13). Therefore, even if some external force is applied to the outermost surface of the protective layer (11), coating defects such as detachment or peeling are unlikely to occur in the protective layer (11) itself. Furthermore, such external forces are transmitted to the printed layer (12) and then to the undercoat layer (13), but because both layers are relatively soft, the force is mitigated in both layers. As a result, it is thought that defects such as peeling, detachment, and misalignment will not occur in the printed layer (12). To make the resistance of the printed layer more favorable, it is preferable that Tm(11)(°C) is 130°C or higher, Tm(12)(°C) is less than 130°C, and Tm(13)(°C) is also less than 130°C. More preferably, it is preferable that Tm(11)(°C) is 150°C to 220°C, Tm(12)(°C) is 60°C to 120°C, and Tm(13)(°C) is 60°C to 120°C.

[0048] The protective layer (11) is the outermost layer of the lid laminate (1), and also enhances the strength, durability, weather resistance, and chemical resistance of the lid laminate (1) and the lid (2). It is composed of various known overcoat agents capable of performing these functions. The overcoat agent is a composition containing a thermoplastic resin and an organic solvent, and may also contain the additives described below. However, it does not contain the colorants described below. Various known thermoplastic resins can be used without particular limitation, including synthetic resins and natural resins. Examples of natural resin-based thermoplastics include shellac resin and cellulose-based resins, the latter being preferable in terms of the strength, scratch resistance, and water resistance of the protective layer. Examples of cellulose-based thermoplastics include nitrocellulose, cellulose propionate, cellulose acetate / butyrate, benzylcellulose, ethylcellulose, and methylcellulose. Examples of synthetic resin-based thermoplastic resins include, Examples include chlorinated polyolefins (chlorinated polyethylene, chlorinated polypropylene, etc.), polyamide resins, acrylic resins (polymethyl methacrylate, etc.), vinyl chloride-vinyl acetate copolymers, and polyesters (unsaturated copolymer polyesters, saturated copolymer polyesters, etc.). Various known organic solvents can be used without particular limitation, such as toluene, xylene, acetone, methyl ethyl ketone, ethyl acetate, butyl acetate, methanol, ethanol, and isopropyl alcohol (hereinafter, the same applies when referring to organic solvents). The protective layer (11) can be formed by known printing methods such as bar coater printing, gravure printing, offset printing, and flexographic printing, and may be a single coat or a multi-coat.

[0049] The printed layer (12) is an interposed layer between the protective layer (11) and the undercoat layer (13), forming letters, figures, and symbols, and providing information about the contents (C) of the packaging (4) and the design to the lid laminate (1) and lid (2). The printed layer (12) is composed of various known printing inks. The printing ink is a composition obtained by dissolving or dispersing a coloring agent in a vehicle containing a thermoplastic resin and an organic solvent, and may also include the aforementioned additives. The thermoplastic resin can be any known type that can be used as a binder resin for printing inks, without any particular limitations, and examples include synthetic resins and natural resins. Examples of synthetic resin-based thermoplastic resins include chlorinated polyolefins (chlorinated polyethylene, chlorinated polypropylene, etc.), polyamide resins, acrylic resins (polymethyl methacrylate, etc.), vinyl chloride-vinyl acetate copolymers, and polyesters (unsaturated copolymer polyesters, saturated copolymer polyesters, etc.). Examples of natural resin-based thermoplastics include shellac resin and cellulose-based resins. Examples of cellulose-based thermoplastics include nitrocellulose, cellulose propionate, cellulose acetate / butyrate, benzylcellulose, ethylcellulose, and methylcellulose. Examples of colorants include pigments and / or dyes. Examples of pigments include organic or inorganic pigments such as titanium dioxide, zinc oxide, gloss white, palite, 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 for example, the average primary particle size should be typically 0.1 to 5 μm, preferably 0.5 to 3 μm. Examples of dyes include anthraquinone dyes, azo dyes, and quinoline dyes. The content of the colorant is not particularly limited, but should be typically 0.5 to 40% by weight, preferably 2 to 10% by weight. The printed layer (12) can be formed by known printing methods such as bar coater printing, gravure printing, offset printing, and flexographic printing, and may be single-color or multi-color.

[0050] The undercoat layer (13) is a layer for adhering the protective layer (11) and the printing layer (12), or the printing layer (12) alone, to the outer surface of the barrier layer (14), and can be composed of various known anchor coating agents (hereinafter sometimes referred to as outer anchor coating agents) that can perform such a function. The outer anchor coating agent contains a thermoplastic resin and an organic solvent as a vehicle, and may also contain the aforementioned additives. However, it does not contain the aforementioned coloring agent. Therefore, the undercoat layer (13) has excellent adhesion to the metal foil constituting the barrier layer (14). Any known thermoplastic resin can be used without particular limitation as long as it can perform the aforementioned function of the undercoat layer (13), and both synthetic resins and natural resins can be used. Examples of synthetic resin-based thermoplastic resins include chlorinated polyolefins (chlorinated polyethylene, chlorinated polypropylene, etc.), polyamide resins, acrylic resins (polymethyl methacrylate, etc.), vinyl chloride-vinyl acetate copolymers, and polyesters (unsaturated copolymer polyesters, saturated copolymer polyesters, etc.). Examples of natural resin-based thermoplastic resins include shellac resin and cellulose-based resins. Examples of the latter include nitrocellulose, cellulose propionate, cellulose acetate / butyrate, benzylcellulose, ethylcellulose, and methylcellulose. The undercoat layer (13) can be formed by known printing methods such as bar coater printing, gravure printing, offset printing, and flexographic printing, and may be single-color printing, single-coat, or multi-coat.

[0051] Additives are included as needed in the overcoat agent, printing ink, and outer anchor coat agent, respectively, for the purpose of enhancing the functionality of each layer: the protective layer (11), the printing layer (12), and the undercoat layer (13). Examples of additives include various known curing agents, curing catalysts, surfactants, plasticizers, and silane coupling agents (hereinafter, the same applies when referring to additives). Various known curing agents can be used without particular limitation, such as melamine-based curing agents, epoxy-based curing agents, isocyanate-based curing agents, and epoxy-melamine-based curing agents. Examples of curing catalysts include metal carboxylate-based catalysts, organotin-based catalysts, and amine-based catalysts. Examples of surfactants include anionic surfactants, cationic surfactants, amphoteric surfactants, and nonionic surfactants. Examples of plasticizers include alkyl polycarboxylate esters, such as alkyl adipate esters, alkyl phthalate esters, alkyl phosphate esters, and alkyl trimellitate esters. Examples of silane coupling agents include alkoxysilanes such as γ-chloropropyltrimethoxysilane, vinyltrichlorosilane, vinyltriethoxysilane, vinyl-tris(β-methoxyethoxy)silane, γ-methacrylateoxypropyltrimethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, and γ-glycidoxypropyltrimethoxysilane. Additives may be the same, of the same type, or of different types, and may be combined.

[0052] The thicknesses of the protective layer (11), the printed layer (12), and the undercoat layer (13) are not particularly limited, but from the viewpoint of print layer resistance, when the total thickness of all layers is considered to be 1, it is generally preferable that the thickness ratio of the protective layer (11) is 34% to 85%, the thickness ratio of the printed layer (12) is 7% to 33%, and the thickness ratio of the undercoat layer (13) is 8% to 33%, with more preferably being 72% to 85%, 7% to 9%, and 8% to 19%, respectively.

[0053] The specific thicknesses of the protective layer (11), the printed layer (12), and the undercoat layer (13) are not particularly limited, but from the viewpoint of print layer resistance, it is generally preferable that the thickness of the protective layer (11) is 0.5 μm to 30 μm, the thickness of the printed layer (12) is 0.5 μm to 4 μm, and the thickness of the undercoat layer (13) is 0.5 μm to 7 μm, and more preferably 5 μm to 20 μm, 0.5 μm to 2 μm, and 0.5 μm to 5 μm, respectively.

[0054] In the case of the laminated material for the lid (1), it is preferable that the thermoplastic resin forming the printing layer (12) and the thermoplastic resin forming the undercoat layer (13) are the same or of the same type, as this improves the adhesion between the two layers and enhances the resistance of the printing layer. Specifically, examples include unifying the thermoplastic resin forming the printing layer (12) and the thermoplastic resin forming the undercoat layer (13) with the aforementioned cellulose-based resin or unifying them with the aforementioned synthetic resin, with the latter being preferable in terms of resistance of the printing layer.

[0055] Furthermore, in the case of the lid laminate (1), a combination in which both the thermoplastic resin forming the printing layer (12) and the thermoplastic resin forming the undercoat layer (13) are different from the thermoplastic resin forming the protective layer (11) is preferable because it further improves the resistance of the printing layer. Specifically, an example is a configuration in which the thermoplastic resin forming the protective layer (11) is a cellulose-based thermoplastic resin, the thermoplastic resin forming the printing layer (12) is a synthetic resin-based thermoplastic resin, and the thermoplastic resin forming the undercoat layer (13) is also a synthetic resin-based thermoplastic resin.

[0056] The barrier layer (14) is a layer that protects the contents (C) contained in the packaging (4) from gas, water vapor, light, etc., and is made of metal foil. The physical properties of the metal foil are not particularly limited, but for example, if the tensile strength at break is 20 to 200 MPa and the total elongation at break is 5 to 50%, the strength of the lid laminate (1) will increase, and the lid (2) will be less likely to tear when the packaging (4) is opened. In addition, since no cracks occur in the metal foil forming the barrier layer (14), the resistance to internal pressure cracks of the lid laminate (1) and the lid (2) will also be good. Both the tensile strength and total elongation are measured values ​​based on the metal material tensile test method specified in JIS Z2241. Examples of metal foils include aluminum foil, iron foil, stainless steel foil, copper foil, and nickel foil. Among these, aluminum foil is preferred considering barrier function, formability, and cost. Here, "aluminum foil" refers to "pure aluminum foil" or "aluminum alloy foil." As for pure aluminum foil, pure aluminum foil with a purity of 99.0% by mass or higher is particularly preferred. As for aluminum alloy foil, Al-Fe aluminum alloy foil is preferred, and in particular, aluminum alloy foil containing 0.7 to 1.3% by mass of Fe and 0.05 to 0.3% by mass of Si, with the remainder being Al and unavoidable impurities, or aluminum alloy foil containing 1.2 to 1.7% by mass of Fe and 0.15% by mass or less of Si, with the remainder being Al and unavoidable impurities, is preferred in terms of the formability of the lid (2). The aluminum foil may be either a soft material (O material) or a hard material (H material). Among these, the O-grade aluminum foils of the 1000 series and 8000 series aluminum foils specified in JIS H4160 are preferred in terms of moldability. Specifically, A1N30H-O, A8021H-O, and A8079H-O are preferred. The metal foil may have an easily adhering layer formed on one or both sides using various known chemical conversion solutions. Examples of chemical conversion solutions include water-alcohol solutions containing phosphoric acid, a chromium compound, a fluorine compound, and / or a binder resin. Examples of chromium compounds include chromic acid and / or chromium(III) salts, examples of fluorine compounds include metal salts of fluorides and / or nonmetallic salts of fluorides, and examples of binder resins include at least one selected from the group consisting of acrylic resins, chitosan derivative resins, and phenolic resins. The amount of chemical conversion solution applied should be in the range of 0.1 to 50 mg / m2 per side of the metal foil. The thickness of the barrier layer (14) is not particularly limited, but considering the strength and weather resistance of the lid laminate (1) and lid (2), for example, 5 μm to 80 μm is preferred, and more preferably 20 μm to 35 μm. With such a thickness, the heat from the heat sealer used when heat-sealing the lid (2) to the container (3), and the heat generated by the metal foil when using high-frequency induction heating seals, are more easily transferred to the heat seal layer (17), which is also preferable in terms of productivity.

[0057] The inner undercoat layer (15) is an optional layer used to ensure close adhesion between the barrier layer (14) and the buffer layer (16) and / or the heat seal layer (17), and to prevent delamination between the two layers. It can be composed of various known anchor coating agents (hereinafter sometimes referred to as inner anchor coating agents) that can perform such functions. Examples of inner anchor coating agents 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. When the lid (2) is used as food packaging material, a solvent-free type can be used in particular. Among these, polyurethane resin-based inner anchor coating agents are preferred in terms of print layer resistance because they have good adhesion to metal foil, can form a highly flexible inner undercoat layer (15), and exert a mitigating effect on the outermost surface of the protective layer (11). Suitable polyurethane resin-based anchor coating agents include two-component curing polyether-urethane resin adhesives and / or two-component curing polyester-urethane resin adhesives. Both consist of a main component and a curing agent, with various known polyether polyols and / or polyester polyols being examples of the main component. As curing agents, isocyanate-based curing agents can be used, such as polyisocyanates including hexamethylene diisocyanate, isophorone diisocyanate, tolylene diisocyanate, and diphenylmethane diisocyanate, as well as their derivatives (isocyanurate, biuret, and adduct forms, etc.). The inner undercoat layer (15) can be formed by known printing methods such as bar coater printing, gravure printing, offset printing, and flexographic printing, and may be a single coat or a multi-coat. The thickness of the inner undercoat layer (15) is not particularly limited, but considering the delamination prevention effect and print layer resistance mentioned above, it is usually sufficient to be around 0.5 μm to 7 μm, and preferably around 0.5 μm to 5 μm.

[0058] The buffer layer (16) has the function of improving the print layer resistance, internal pressure sealing resistance, and internal pressure crack resistance of the lid laminate (1) and lid (2) through its buffering action. In addition, by providing the buffer layer (16), the tear strength of the lid laminate (1) and lid (2) is improved, so that resistance to straw punctures can be ensured, for example. The buffer layer (16) is preferably composed of various known polyolefins and may be in the form of a film (stretched or unstretched) 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: Firstly, it has good pressure distribution properties during heat sealing. Secondly, it can better alleviate the external stress that is repeatedly applied to the lid (2) for a long period of time during the transportation of the package (4). Thirdly, it also has good stress relief properties for the barrier layer (14) when the package (4) is opened. Therefore, by using polyethylene as the polyolefin constituting the buffer layer (16), the internal pressure sealing resistance and internal pressure crack resistance of the lid laminate (1) and lid (2) are improved, and cracks and tears in the metal foil forming the barrier layer (14) are reduced. The thickness of the buffer layer (16) is not particularly limited, but is usually 10 μm to 50 μm, preferably 20 μm to 35 μm, from the viewpoint of straw puncture resistance, internal pressure sealing performance, internal pressure crack resistance, and heat sealing performance.

[0059] The heat seal layer (17) is a layer for heat-sealing the lid (2) to the opening periphery (31) of the container (3), and there are two embodiments of this layer. First aspect: Refer to Figures 1(a), (d), (e), and (f). The heat seal layer (17) is composed of a single layer made of a heat-fusible resin. Second aspect: Refer to Figures 1(b) and 1(c). The heat seal layer (17) is composed of a base layer (17a) and a heat seal layer (17b). Hereinafter, when the term "heat seal layer (17)" is used, it refers to both the heat seal layer (17) of the first embodiment and the heat seal layer (17) of the second embodiment, unless otherwise specified.

[0060] The heat seal layer (17) of the first embodiment is made of a hot melt adhesive or a heat-sealable resin film. Hot melt adhesives are compositions comprising a base resin, a tackifying resin, and optionally a wax, and various known materials can be used. Examples of base resins include polyolefins and ethylene vinyl acetate copolymers. Examples of polyolefins include polyethylene and polypropylene. Examples of vinyl acetate copolymers include ethylene-vinyl acetate copolymer (EVA) and ethylene-ethyl acrylate-vinyl acetate copolymer. Examples of tackifying resins include rosin, disproportionated rosin, rosin esters, terpene resins, C5 petroleum resins, C9 petroleum resins, and C5-C9 petroleum resins. The amount of tackifying resin used is not particularly limited, but is usually about 10 to 50 parts by weight per 100 parts by weight of base resin. Examples of waxes include natural waxes, mineral waxes, petroleum waxes, and synthetic waxes. Examples of animal and plant waxes include candelilla wax, carnauba wax, rice wax, wood wax, beeswax, whale wax, shellac wax, and lanolin wax. Examples of mineral waxes include montane 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, waxes obtained by grafting styrene onto polyethylene-polypropylene copolymers, silicone waxes, fluorine waxes, and amide waxes (oleic acid amide, ricinoleic acid amide, erucic acid amide, N,N'-methylenebisstearic acid amide, N,N'-ethylenebisoleic acid amide, stearic acid monomethylolamide, silinoleic acid amide wax, and stearic acid ester wax, etc.), and composites thereof. Examples of heat-sealable resin films include films made from homopolypropylene (hPP), ethylene-propylene random copolymer (rPP), and ethylene-propylene block copolymer (bPP), as well as polyethylene (PE) such as low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), and high-density polyethylene (HDPE), and films made from polyvinyl resin such as polystyrene resin. The heat-sealable resin film may be multilayered, and examples include a multilayer film obtained by co-extruding at least two types of heat-sealable resins, a multilayer film obtained by laminating at least two types of heat-sealable resin films, and a multilayer film consisting of a heat-sealable resin film and an extruded layer made of heat-sealable resin.

[0061] In the second embodiment, the base layer (17a) is a layer provided for the purpose of ensuring the leveling properties of the heat seal layer (17b), thereby assisting the heat seal between the lid (2) and the opening periphery (31) of the container (3), and further increasing the strength of the lid (2), and is composed of various known synthetic resins. Examples of synthetic resins include polyolefins, which may be in film form or extruded layer form. Examples of polyolefins include homopolypropylene (hPP), ethylene-propylene random copolymer (rPP), and ethylene-propylene block copolymer (bPP), as well as polyethylene (PE) such as low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), and high-density polyethylene (HDPE). The heat seal layer (17b) in the second embodiment can be formed from a heat-fusible resin film that constitutes the heat seal layer (17) in the first embodiment. The heat-fusible resin film may be multilayered, as described above, and can take the form of a multilayer film. The heat seal layer (17) of the second embodiment can be manufactured as an independent component (composite film). For example, this can be done by co-extruding a synthetic resin forming the base layer (17a) and a heat-sealable resin forming the heat seal layer (17b), or by extruding the synthetic resin forming the base layer (17a) onto a heat seal layer (17b) that has been manufactured once. Various known extrusion methods (sheet extrusion, T-die, inflation, etc.) can be used.

[0062] Both the heat seal layer (17) of the first embodiment and the heat seal layer (17b) of the second embodiment are preferable because, compared to the case where they are made of a hot melt adhesive, the heat sealability (especially the heat seal strength) of the lid (2) is better.

[0063] In terms of heat sealability, it is preferable that the heat-sealable resin forming the heat-sealable layer (17) of the first embodiment and the heat-sealable layer (17b) of the second embodiment are the same or of the same type as the resin forming the opening periphery (31) of the container (3). A specific combination is an embodiment in which both the heat-sealable layer (17) of the first embodiment and the heat-sealable layer (17b) of the second embodiment are made of polyvinyl resin (preferably polystyrene), and the resin forming the opening periphery (31) is made of polyvinyl resin (preferably polystyrene).

[0064] In both the first and second embodiments, the overall thickness of the heat seal layer (17) is typically 5 μm to 50 μm, preferably 25 μm to 35 μm, considering heat sealability. In this regard, when the heat seal layer (17) is composed of a hot melt adhesive, the coating amount is typically 10 to 25 g / m². 2 Preferably 12-20 g / m 2 It would be good if that were the case.

[0065] Furthermore, from the viewpoint of heat sealability, the heat seal layer (17) of the second embodiment preferably has a ratio (T17a / T17b) of the thickness of the heat seal layer (17b) to the thickness of the base layer (17a) (T17a).

[0066] A predetermined embossed pattern (18) may be formed over the entire innermost surface of the heat seal layer (17). 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), resulting in improved flatness of the lid (2) in the packaging (4) and good resistance to internal pressure sealing of the packaging (4).

[0067] The embossed pattern (18) consists of a plurality of independent protrusions (18a), as shown in Figures 1(d), (e), (f) and 2(d). The protrusions (18a) are scattered on a continuous base surface (18c) at predetermined intervals (18b). The shape of the protrusions (18a) is not particularly limited, as long as they are independent, single-unit raised structures, and may be rhomboid (Figure 2(a)), cylindrical or dot-shaped (Figures 2(b) and (d)), elliptical, prismatic, conical, trapezoidal, staggered, annular, dome-shaped, etc. For example, the protrusions (18a) in Figure 2(d) are roughly cylindrical with flat tops and are arranged regularly and periodically on a flat base surface (18c) at regular intervals (18b). Alternatively, multiple protrusions (18a) of different shapes may be combined to form a specific pattern (Figure 2(c)). The arrangement of the protrusions (18a) is not limited to any particular regularity; it may be periodic, as shown in Figure 2(d), or it may be irregular, although this is not shown in the illustration. The size of the protrusion (18a) is not limited; for example, if the protrusion (18a) is roughly cylindrical as shown in Figure 2(d), the diameter of one unit can be as small as 100 μm to 1000 μm. The density of the protrusions (18a) is not particularly limited, for example, 1 to 130 per cm. 2 A certain degree is acceptable. The height (H) of the protrusion (18) is not particularly limited, but it is sufficient that it is greater than the total thickness (T17) of the heat seal layer (17) and less than the combined thickness (T17 + T16) of the buffer layer (16) and the heat seal layer (17). Doing so allows for more reliable air removal during heat sealing. In this case, (T16) and (T17) are both the thickness before embossing. The size of the spacing (18b) is not particularly limited; for example, if the convex portion (18a) is roughly cylindrical as shown in Figure 2(d), then a spacing of 90 μm to 900 μm is acceptable. The base surface (18c) may be flat or may have a partially concave shape. Considering the flatness, heat sealability, and resistance to internal pressure cracks of the lid (2), it is preferable that the base surface (18c) be flat. Furthermore, it is preferable in terms of heat sealability if the area of ​​the base surface (18c) is larger than the total area of ​​the convex portions (18a).

[0068] The laminated material for the lid (1) can be manufactured by various known lamination methods such as dry lamination, melt (co)extrusion lamination, sandwich lamination, heat lamination, T-die method, comma coater® method, and comma direct® method, and these methods may be combined. As a specific example of manufacturing, taking the sandwich lamination method as an example, a method can be described in which a buffer layer (16) is extruded and bonded to the innermost surface of the inner undercoat layer (15) of an intermediate member (hereinafter referred to as the intermediate member) which has a protective layer (11), a printed layer (12), an undercoat layer (13), a barrier layer (14), and an inner undercoat layer (15).

[0069] The method for forming the embossed pattern (18) on the bottom surface of the heat seal layer (17) of the lid laminate (1) also relies on various known means. Specifically, for example, one method is to press a press roll, which has a predetermined concave pattern (debossed pattern) pre-formed on its surface, onto a heat-sealable resin film forming the heat seal layer (17) to form the embossed pattern (18). Another method is to coat the surface of the buffer layer (16) with a hot-melt adhesive forming the heat seal layer (17) using the same press roll, and simultaneously form the embossed pattern (18). When using a hot-melt adhesive, considering that it becomes highly viscous at high temperatures, it is also advisable to use the T-die method or the comma coater method. The press roll may be a cooling roll or a heating roll. Furthermore, the press roll can also serve as a coating roller, transfer roller, and shaping roller; for example, a gravure roll can be used.

[0070] The laminate material for the lid (1) should have a low residual amount of organic solvent, especially when the contents (C) are products to be ingested orally, such as food or beverages, from the viewpoint of low odor. This organic solvent mainly originates from the protective layer (11), the printing layer (12), the undercoat layer (13), and, in some cases, the inner undercoat layer (15). The residual amount of such organic solvent is measured in accordance with the gas chromatography standard test in accordance with the "Manual for Control Equipment for Manufacturing Flexible Packaging Materials" edited by the Flexible Packaging Hygiene Council. Details will be described in the examples. The residual amount is 5 mg / m². 2 Less than 4 mg / m², preferably 4 mg / m² 2 It is better if it is less than [a certain value].

[0071] <Lid (2)> The lid (2) is made by processing the laminated lid material (1) into a predetermined shape. The shape is not particularly limited and can be determined according to the shape of the container (3) and the opening method of the packaging (4). In addition, an opening tab may be provided on the outer edge of the lid (2) as needed. Furthermore, an opening notch may be engraved on the bottom surface of the heat seal layer (17) of the lid (2) according to the shape of the opening edge (31) of the container (3). The lid (2) in Figure 3(a) and the lid (2) in the packaging (4) in Figure 3(b) are both cap-shaped and consist of a substantially horizontal main body (2a) and a skirt (2b) that hangs down from the periphery of the main body (2a). In addition, the lid (2) in the packaging (4) in Figure 3(c) is sheet-shaped and consists only of a main body (2a).

[0072] <Container (3)> The container (3) can be made from various known materials. Preferred materials include thermoplastic synthetic resins such as polyolefin, polyester, and polyvinyl resin. Other materials such as glass, iron, copper, and aluminum can also be used. If the opening periphery (31) of the container (3) is made of the same or the same type of heat-sealable resin as the heat-sealable resin forming the bottom surface of the heat-seal layer (17), the heat-sealability of the packaging (4) is improved. Therefore, even if the internal pressure of the packaging (4) repeatedly increases or decreases, seal recession will not occur, and leakage of the contents can be prevented. Specific combinations include selecting polyvinyl resin (preferably polystyrene) as the heat-sealable resin forming the opening periphery (31) and selecting polyvinyl resin (preferably polystyrene) as the heat-sealable resin forming the bottom surface of the heat-seal layer (17).

[0073] The manufacturing method for the container (3) is not particularly limited and includes, for example, deep drawing, blow molding, vacuum forming, and pressure forming. The shape of the container (3) is also not particularly limited and includes a bottle shape as shown in Figure 3(b), a flanged cup shape as shown in Figure 3(c), as well as a cylindrical shape, a press-through pack, etc. If the container (3) is bottle-shaped, as shown in Figure 3(b), tapering the neck portion of the container (3) allows for a stable seal. Also, if the container (3) is a flanged cup, an annular opening notch can be engraved at a predetermined location on the upper surface of the flange, which is the opening periphery (31).

[0074] <Contents (C)> Contents (C) include products taken orally, such as dairy products, dairy beverages, lactic acid bacteria beverages, soft drinks, solid or liquid food products like ham, cheese, curry, and sauces, or liquid or solid pharmaceuticals.

[0075] <Package (4)> The packaging (4) is formed by overlapping the lid (2) onto the opening edge (31) of the container (3) containing the contents (C) from the heat-seal layer (17) side, and sealing it by heat-sealing it using various known sealing devices. The sealing conditions are not particularly limited and are determined appropriately according to the material types of the lid (2) and container (3), the specifications of the sealing device, etc. Furthermore, employing high-frequency induction heating as a sealing method is preferable in terms of productivity because it enables high-speed sealing. High-frequency induction heating is particularly preferable when the bottom surface of the heat-seal layer (17) of the lid (2) is made of a heat-sealable resin film, and is even more preferable when an embossed pattern (18) is formed on the film.

[0076] When the packaging (4) is a bottle-shaped container (3) with a rim-shaped opening (31), as shown in Figure 3(b), the lid (2) is preferably a cap-shaped lid. However, when the container (3) is cup-shaped with an annular flange-shaped opening (31), as shown in Figure 3(c), the lid (2) may be a sheet-shaped lid.

[0077] Figure 4 shows a sliding test apparatus (5) used to evaluate the print layer resistance of the lid laminate (1). This apparatus (5) includes a stainless steel support column (51), a stainless steel spherical member (52) (10 mm in diameter) connected to its tip, and a stainless steel support base (53). The total weight of the support column (51) and the spherical member (52) is, for example, 1 kg. The spherical member (52) is covered with cotton gauze (not shown).

[0078] Figure 5 shows the shaking devices (6) and (7).

[0079] The shaking device (6) in Figure 5(a) is used to directly evaluate the print layer resistance of the lid (2) of the packaging body (4). The device (6) consists of a packaging material (61) such as corrugated cardboard and a plurality of samples (62) housed inside it. In this figure, each sample (62) is an assembly formed by connecting two packaging bodies (4) laterally and restraining them from the sides with a binding film (63) such as polyethylene film. The number of samples (62) is not particularly limited and can be appropriately determined according to the dimensions of the packaging material (4) and the size of the packaging body (4). In this figure, three sets of samples are stacked vertically with a partition material (64) in between. The partition material (64) is a component that comes into direct contact with the protective layer (11) of the lid (2), and can be made of a material with a surface texture and a certain strength, such as corrugated cardboard. However, the partition material (64) is optional and may be omitted. In this case, the bottom of one packaging (4) comes into direct contact with the protective layer (11) of the lid (2) of the lower packaging (4).

[0080] The shaking device (7) in Figure 5(b) is used to evaluate the resistance of the lid (2) of the packaging (4) to internal pressure cracking. The device (7) comprises a concave-section housing section (71) for setting the packaging (4), side walls (72) rising from the periphery of the bottom wall of the housing section (71), and a pair of contact members (73) provided midway between the heights of the left and right side walls (72). The housing section (71) is connected to a drive motor (not shown), and when this motor is started, the housing section (71) is vibrated in small increments in the left-right direction shown in the figure at a predetermined number of times per minute (for example, 120 times / minute), and the packaging (4) is also shaken from side to side in conjunction with this. With each shake, the pair of contact members (73) continuously collide with the main body of the packaging (4), and the side walls of the packaging (4) are alternately pressed, causing the internal pressure of the packaging (4) to repeatedly increase and decrease. Each time the internal pressure increases or decreases, the lid (2) is heat-fused to the opening periphery (31) and deforms outward (in the direction of the upward arrow (D1)) before returning to its original shape, or deforms inward (in the direction of the downward arrow (D2)) before returning to its original shape. As such expansion and recovery are repeated, cycle fatigue accumulates in the metal foil forming the barrier layer (14) of the lid (2), and when the metal foil can no longer withstand the cycle fatigue, cracks occur. In this regard, the lid (2) of the present invention, as mentioned above, has excellent resistance to internal pressure cracking. In particular, if the lid (2) of the packaging body (4) is made of a heat-sealable resin film on the bottom surface of the heat-seal layer (17), the resistance to internal pressure cracking of the lid (2) is improved, and the metal foil does not crack due to the cycle fatigue described above. In this figure, the packaging body (4) contains contents (C), but the contents (C) may be omitted if the purpose of the internal pressure cracking resistance test is achieved. [Examples]

[0081] The following describes in more detail the structure of the lid laminate, lid, and packaging body of the present invention, as well as their effects, through examples and comparative examples. However, the technical scope of the present invention is not limited by these specific examples.

[0082] <1. Fabrication of the laminated material for the lid (1)>

[0083] <1-1. The bottom surface of the heat seal layer (17) is a heat-sealable resin film>

[0084] Example 1 A 1.0 μm thick undercoat layer was formed by applying a commercially available outer anchor coating agent to one side of a 25 μm thick aluminum foil (JIS H4160: A8021-O material) using a gravure roll, then heating and drying it. This outer anchor coating agent is a composition based on vinyl chloride-vinyl acetate copolymer (hereinafter referred to as VCVA: glass transition temperature 70°C, melting point 95°C) and contains ethyl acetate as an organic solvent. Next, a white printing ink, which was prepared by dispersing 10% by weight of titanium dioxide in the same anchor coating agent as the outer anchor coating agent, was applied to the surface of this undercoat layer using a gravure roll, and then heated and dried to form a printed layer with a thickness of 1.5 μm. Next, an ethyl acetate solution of nitrocellulose (hereinafter referred to as NC: glass point temperature 130°C, melting point 160°C) (non-volatile content 10% by weight) was applied to the surface of this printed layer as an overprint coating agent using a gravure roll, and then heated and dried to form a protective layer with a thickness of 10 μm, thereby producing intermediate member A1. Next, a commercially available two-component curing polyester polyurethane adhesive (two-component PU) was applied to the other side of the aluminum foil forming the intermediate member A1 using a gravure roll as an inner anchor coating agent, and then heated and dried to form an inner undercoat layer with a thickness of 2.0 μm. Next, a composite film A1 for the heat seal layer was fabricated by co-extrusion. This composite film A1 consists of a 7.0 μm thick base layer made of low-density polyethylene (LDPE) and a 23 μm thick heat seal layer made of polystyrene (PS). Next, molten low-density polyethylene (LDPE) was extruded onto the inner undercoat layer of intermediate member A1 through a T-die to form a 30 μm thick buffer layer. While this was happening, the composite film A1 was sandwich-laminated from the base layer side through a cooling roll with a smooth surface to produce a lid laminate A1 without an embossed pattern.

[0085] Example 2 The same intermediate member A1 and composite film A1 prepared in Example 1 were then prepared and designated as intermediate member A2 and composite film A2, respectively. Next, a commercially available two-component curing polyester polyurethane adhesive (two-component PU) was applied to the other side of the aluminum foil forming the intermediate member A2 using a gravure roll as an inner anchor coating agent, and then heated and dried to form an inner undercoat layer with a thickness of 2.0 μm. Next, the composite film A2 was laminated to the intermediate member A2 as follows. Specifically, molten low-density polyethylene (LDPE) was extruded through a T-die onto the inner undercoat layer of the intermediate member A2 to form a 30 μm thick buffer layer. The composite film A2 was then sandwich-laminated from the base layer side by passing it through a cooling roll (gravure roll) with a concave pattern formed on its surface, thereby producing a laminated lid material A2 with an embossed pattern. This embossed pattern is dot-shaped (see Figures 2(b) and 2(d)), with the raised parts having a diameter of 750 μm, a height of 50 μm, and a density of 2.2 dots / cm³. 2 The spacing was 500 μm, and the base surface was flat (hereinafter, when referring to the embossed pattern, the same applies).

[0086] Example 3 In Example 1, a lid laminate A3 without an embossed pattern was prepared by following the same procedure as in Example 1, except that the undercoat layer was formed as a 1.0 μm thick dry coating film made of a commercially available outer anchor coating agent based on thermoplastic polyester (hereinafter referred to as PEs: glass transition temperature -10°C, melting point 110°C) and containing methyl ethyl ketone as an organic solvent, and the printed layer was formed as a 1.5 μm thick dry coating film made of a white printing ink in which 10% by weight of titanium dioxide was dispersed in the same outer anchor coating agent.

[0087] Example 4 In Example 2, a laminated lid material A4 with an embossed pattern was prepared by following the same procedure as in Example 2, except that the undercoat layer was formed as a 1.0 μm thick dry coating film made of a commercially available outer anchor coating agent based on thermoplastic polyester (PEs) and containing methyl ethyl ketone as an organic solvent, and the printed layer was formed as a 1.5 μm thick dry coating film made of a white printing ink in which 10% by weight of titanium dioxide was dispersed in the outer anchor coating agent.

[0088] Example 5 In Example 1, a laminated lid material A5 without an embossed pattern was prepared by following the same procedure as in Example 1, except that the undercoat layer was formed as a 1.0 μm thick dry coating film made of an outer anchor coating agent based on thermoplastic polyester (PEs) and containing methyl ethyl ketone as an organic solvent, and the printed layer was formed as a 1.5 μm thick dry coating film made of a white printing ink containing vinyl chloride-vinyl acetate copolymer (VCVA) as a binder component and 10% by weight of titanium dioxide dispersed in it.

[0089] Example 6 In Example 2, a laminated lid material A6 with an embossed pattern was prepared by following the same procedure as in Example 2, except that the undercoat layer was formed as a 1.0 μm thick dry coating film made of an outer anchor coating agent based on thermoplastic polyester (PEs) and containing methyl ethyl ketone as an organic solvent, and the printed layer was formed as a 1.5 μm thick dry coating film made of a white printing ink containing vinyl chloride-vinyl acetate copolymer (VCVA) as a binder component and 10% by weight of titanium dioxide dispersed in it.

[0090] Example 7 In Example 1, a lid laminate A7 without an embossed pattern was prepared by following the same procedure as in Example 1, except that the protective layer was formed with a 10 μm thick dry coating film made of an ethyl acetate solution of cellulose propionate (hereinafter referred to as CP: glass transition temperature 150°C, melting point 190°C) (non-volatile content 10% by weight).

[0091] Example 8 In Example 2, a laminated lid material A8 with an embossed pattern was prepared by following the same procedure as in Example 2, except that the protective layer was formed with a 10 μm thick dry coating film made of an ethyl acetate solution of cellulose propionate (CP) (10% by weight of non-volatile content).

[0092] Example 9 In Example 1, a lid laminate A9 without an embossed pattern was prepared by following the same procedure as in Example 1, except that the undercoat layer was formed as a 1.0 μm thick dry coating film made of an outer anchor coating agent based on thermoplastic polyester (PEs) and containing methyl ethyl ketone as an organic solvent, and the protective layer was formed as a 10 μm thick dry coating film made of an ethyl acetate solution of cellulose propionate (CP) (10% by weight of non-volatile content).

[0093] Example 10 In Example 2, a laminated lid material A10 with an embossed pattern was prepared by following the same procedure as in Example 2, except that the undercoat layer was formed as a 1.0 μm thick dry coating film made of an outer anchor coating agent based on thermoplastic polyester (PEs) and containing methyl ethyl ketone as an organic solvent, and the protective layer was formed as a 10 μm thick dry coating film made of an ethyl acetate solution of cellulose propionate (CP) (10% by weight of non-volatile content).

[0094] Example 11 In Example 1, a lid laminate A11 without an embossed pattern was prepared by following the same procedure as in Example 1, except that the protective layer was formed with a 10 μm thick dry coating film made of an overprint coating agent based on benzyl cellulose (hereinafter referred to as BC: glass transition temperature 100°C, melting point 190°C) and containing ethyl acetate as an organic solvent.

[0095] Example 12 In Example 2, a laminated lid material A12 with an embossed pattern was prepared by following the same procedure as in Example 2, except that the protective layer was formed with a 10 μm thick dry coating film made of an overprint coating agent based on benzyl cellulose (BC) and containing ethyl acetate as an organic solvent.

[0096] Example 13 In Example 1, a laminated lid material A13 without an embossed pattern was prepared by following the same procedure as in Example 1, except that the undercoat layer was formed as a 1.0 μm thick dry coating film made of an outer anchor coating agent based on thermoplastic polyester (PEs) and containing methyl ethyl ketone as an organic solvent, the printing layer was formed as a 1.5 μm thick dry coating film made of a white printing ink in which 10% by weight of titanium dioxide was dispersed in the outer anchor coating agent, and the protective layer was formed as a 10 μm thick dry coating film made of an overprint coating agent based on benzyl cellulose (BC) and containing ethyl acetate as an organic solvent.

[0097] Example 14 In Example 2, a laminated lid material A14 with an embossed pattern was prepared by following the same procedure as in Example 2, except that the undercoat layer was formed as a 1.0 μm thick dry coating film made of an outer anchor coating agent based on thermoplastic polyester (PEs) and containing methyl ethyl ketone as an organic solvent, the printing layer was formed as a 1.5 μm thick dry coating film made of a white printing ink in which 10% by weight of titanium dioxide was dispersed in the outer anchor coating agent, and the protective layer was formed as a 10 μm thick dry coating film made of an overprint coating agent based on benzyl cellulose (BC) and containing ethyl acetate as an organic solvent.

[0098] Comparative Example 1 In Example 1, a lid laminate B1 without an embossed pattern was prepared by following the same procedure as in Example 1, except that the protective layer was formed with a 10 μm thick dry coating made of an overprint coating agent based on vinyl chloride-vinyl acetate copolymer (VCVA) and containing ethyl acetate as an organic solvent.

[0099] Comparative Example 2 In Example 2, a laminated lid material B2 with an embossed pattern was prepared by following the same procedure as in Example 2, except that the protective layer was formed with a 10 μm thick dry coating film made of an overprint coating agent based on vinyl chloride-vinyl acetate copolymer (VCVA) and containing ethyl acetate as an organic solvent.

[0100] Comparative Example 3 In Example 1, a laminated lid material B3 without an embossed pattern was prepared by following the same procedure as in Example 1, except that the protective layer was formed with a 10 μm thick dry coating film made of an overprint coating agent based on chlorinated polyethylene (hereinafter referred to as PE-C: glass transition temperature 40°C, melting point 80°C) and containing ethyl acetate as an organic solvent.

[0101] Comparative Example 4 In Example 2, a laminated lid material B4 with an embossed pattern was prepared by following the same procedure as in Example 2, except that the protective layer was formed with a 10 μm thick dry coating film made of an overprint coating agent based on chlorinated polyethylene (PE-C) and containing ethyl acetate as an organic solvent.

[0102] Comparative Example 5 In Example 1, a laminated lid material B5 without an embossed pattern was prepared by following the same procedure as in Example 1, except that the protective layer was formed as a 10 μm thick dry coating film made of an overprint coating agent based on vinyl chloride-vinyl acetate copolymer (VCVA) and containing ethyl acetate as an organic solvent, and the printed layer was formed as a 1.5 μm thick dry coating film made of a white printing ink containing nitrocellulose (NC) as a binder component and 10% by weight of titanium dioxide dispersed in it.

[0103] Comparative Example 6 In Example 1, a laminated lid material B6 with an embossed pattern was prepared by following the same procedure as in Example 1, except that the protective layer was formed as a 10 μm thick dry coating film made of an overprint coating agent based on vinyl chloride-vinyl acetate copolymer (VCVA) and containing ethyl acetate as an organic solvent, and the printed layer was formed as a 1.5 μm thick dry coating film made of a white printing ink containing nitrocellulose (NP) as a binder component and 10% by weight of titanium dioxide dispersed in it.

[0104] Comparative Example 7 In Example 1, a laminated lid material B7 without an embossed pattern was prepared by following the same procedure as in Example 1, except that the protective layer was formed with a 10 μm thick dry coating film made of an overprint coating agent based on polymethyl methacrylate (hereinafter referred to as PMMA: glass transition temperature 70°C, melting point 140°C) and containing ethyl acetate as an organic solvent, and the undercoat layer was formed with a 1.0 μm thick dry coating film made of a commercially available outer anchor coating agent based on thermoplastic polyester (PEs) and containing methyl ethyl ketone as an organic solvent.

[0105] Comparative Example 8 In Example 2, a laminated lid material B8 with an embossed pattern was prepared by following the same procedure as in Example 2, except that the protective layer was formed with a 10 μm thick dry coating film made of an overprint coating agent based on polymethyl methacrylate (PMMA) and containing ethyl acetate as an organic solvent, and the undercoat layer was formed with a 1.0 μm thick dry coating film made of a commercially available outer anchor coating agent based on thermoplastic polyester (PEs) and containing methyl ethyl ketone as an organic solvent.

[0106] Comparative Example 9 In Example 1, a laminated lid material B9 without an embossed pattern was prepared by following the same procedure as in Example 1, except that the protective layer was formed as a 10 μm thick dry coating film made of an overprint coating agent based on benzyl cellulose (BC) and containing ethyl acetate as an organic solvent, and the printed layer was formed as a 1.5 μm thick dry coating film made of a white printing ink containing benzyl cellulose (BC) as a binder component and 10% by weight of titanium dioxide dispersed in it.

[0107] Comparative Example 10 In Example 2, the protective layer was formed of a dry coating film with a thickness of 10 μm made of an overprint coating agent based on benzyl cellulose (BC) and containing ethyl acetate as an organic solvent, and the printing layer was formed of a dry coating film with a thickness of 1.5 μm made of a white printing ink containing benzyl cellulose (BC) as a binder component and having 10% by weight of titanium dioxide dispersed therein. A laminated material B10 for a lid with an embossed pattern was produced according to the same procedure except for the above.

[0108] <1-2. Aspect where the heat seal layer (17) is made of a hot melt adhesive>

[0109] Example 15 The same intermediate member A1 produced in Example 1 was prepared and designated as intermediate member A15. Next, a commercially available two-component curable polyester polyurethane-based adhesive (two-component PU) as an inner anchor coating agent was applied by a gravure roll onto the other surface of the aluminum foil forming the intermediate member A15, and heated and dried to form an inner undercoat layer with a thickness of 2.0 μm. Next, molten low-density polyethylene (LDPE) was extruded onto this inner undercoat layer to form a buffer layer with a thickness of 30 μm. Next, a hot melt adhesive based on ethylene-vinyl acetate copolymer (EVA) and containing a rosin-based tackifier resin was applied onto this buffer layer (14 g / m 2 ), and a heat seal layer with a thickness of 30 μm was formed to produce a laminated material A15 for a lid without an embossed pattern.

[0110] Example 16 In the laminated material A15 for a lid, the heat seal layer was formed by applying the hot melt adhesive used in Example 15 using a high-temperature gravure roll (hereinafter referred to as a patterned high-temperature gravure roll) having a concave pattern formed on the surface, with a thickness of 30 μm (coating amount 14 g / m 2A lid laminate A16 was fabricated by constructing it with a heat-seal layer having an embossed pattern. The embossed pattern formed on the innermost surface of the heat-seal layer was a transfer of the concave pattern of the high-temperature gravure roll, and its shape was the same as the embossed pattern in Example 2.

[0111] Example 17 In the case of the laminated lid material A15, a laminated lid material A17 without an embossed pattern was fabricated by constructing the undercoat layer with a 1.0 μm thick dry coating film made of a commercially available outer anchor coating agent that is thermoplastic polyester (PEs) based and contains methyl ethyl ketone as an organic solvent.

[0112] Example 18 In the laminated lid material A17, the heat-seal layer is coated with the same hot-melt adhesive used in Example 15 using a patterned high-temperature gravure roll, resulting in a thickness of 30 μm (coating amount 14 g / m²). 2 A laminated lid material A18 with an embossed pattern was fabricated by constructing it with a heat-seal layer of ).

[0113] Example 19 Laminated lid material A19 without an embossed pattern was fabricated following the same procedure as laminated lid material A15, except that the protective layer was formed with a 10 μm thick dry coating made of an overprint coating agent based on benzyl cellulose (BC) and containing ethyl acetate as an organic solvent.

[0114] Example 20 In the laminated lid material A19, the heat-seal layer is coated with the same hot-melt adhesive used in Example 15 using a patterned high-temperature gravure roll, resulting in a thickness of 30 μm (coating amount 14 g / m²). 2 By constructing it with a heat-seal layer, a laminated lid material A20 with an embossed pattern was fabricated.

[0115] Example 21 A lid laminate A21 without an embossed pattern was fabricated following the same procedure as the lid laminate A15, except that the protective layer was formed with a 10 μm thick dry coating made of an overprint coating agent based on benzyl cellulose (BC) and containing ethyl acetate as an organic solvent, and the undercoat layer was formed with a 1.0 μm thick dry coating made of a commercially available outer anchor coating agent based on thermoplastic polyester (PEs) and containing methyl ethyl ketone as an organic solvent.

[0116] Example 22 In the laminated lid material A21, the heat-seal layer is coated with the same hot-melt adhesive used in Example 15 using a patterned high-temperature gravure roll, resulting in a thickness of 30 μm (coating amount 14 g / m²). 2 By constructing it with a heat-seal layer, a laminated lid material A22 with an embossed pattern was fabricated.

[0117] Comparative Example 11 In the lid laminate A15, a lid laminate B11 without an embossed pattern was fabricated by constructing the protective layer as a 10 μm thick dry coating film made of an overprint coating agent based on vinyl chloride-vinyl acetate copolymer (VCVA) and containing ethyl acetate as an organic solvent.

[0118] Comparative Example 12 In the laminated material B11 for the lid, the heat seal layer is coated with the same hot melt adhesive used in Example 15 using a patterned high-temperature gravure roll, resulting in a thickness of 30 μm (coating amount 14 g / m²). 2 A laminated lid material B12 with an embossed pattern was fabricated by constructing it with a heat-sealing layer.

[0119] Comparative Example 13 In the lid laminate A15, a lid laminate B13 without an embossed pattern was fabricated by constructing the protective layer as a 10 μm thick dry coating film made of an overprint coating agent based on chlorinated polyethylene (PE-C) and containing ethyl acetate as an organic solvent.

[0120] Comparative Example 14 In the laminated material B13 for the lid, the heat-seal layer is coated with the same hot-melt adhesive used in Example 15 using a patterned high-temperature gravure roll, resulting in a thickness of 30 μm (coating amount 14 g / m²). 2 A laminated lid material B14 with an embossed pattern was fabricated by forming a heat-seal layer of ).

[0121] Comparative Example 15 Laminated lid material B15 without an embossed pattern was fabricated following the same procedure as laminated lid material A15, except that the protective layer was formed with a 10 μm thick dry coating film made of an overprint coating agent based on polymethyl methacrylate (PMMA) and containing ethyl acetate as an organic solvent, and the undercoat layer was formed with a 1.0 μm thick dry coating film made of a commercially available outer anchor coating agent based on thermoplastic polyester (PEs) and containing methyl ethyl ketone as an organic solvent.

[0122] Comparative Example 16 In the laminated lid material B15, the heat-seal layer is coated with the same hot-melt adhesive used in Example 15 using a patterned high-temperature gravure roll, resulting in a thickness of 30 μm (coating amount 14 g / m²). 2 A laminated lid material B16 with an embossed pattern was fabricated by forming a heat-seal layer of ).

[0123] Comparative Example 17 In the laminated lid material A15, a 10 μm thick dry coating film was formed as the protective layer of an overprint coating agent based on benzyl cellulose (BC) and containing ethyl acetate as an organic solvent, and a 1.5 μm thick dry coating film was formed as the printed layer of a white printing ink containing benzyl cellulose (BC) as a binder component and 10% by weight of titanium dioxide dispersed in it, thereby creating a laminated lid material B17 without an embossed pattern.

[0124] Comparative Example 18 In the laminated material B17 for the lid, the heat-seal layer is coated with the same hot-melt adhesive used in Example 15 using a patterned high-temperature gravure roll, resulting in a thickness of 30 μm (coating amount 14 g / m²). 2 A laminated lid material B18 with an embossed pattern was fabricated by forming a heat-seal layer of ).

[0125] Tables 1 to 3 show the layer configuration of the laminated lid material for the examples and comparative examples.

[0126] <2. Evaluation of residual amount of organic solvent in the laminated material for the lid (1)> The amount of organic solvent remaining per unit area of ​​the lid laminate (1) was measured in accordance with the gas chromatography standard test method described in the "Manual for Control Equipment Related to the Manufacturing of Flexible Packaging Materials" compiled by the Flexible Packaging Hygiene Council. An Agilent 7820 gas chromatography apparatus (with HP-5 column) manufactured by Agilent Technologies was used. A Danny HSS8650 headspace sampler was used. The detector settings were: heater temperature 230°C, air flow rate 400 l / min, H2 flow rate 30 ml / min, and N2 flow rate 25 ml / min. The measurement sample was a 10 cm x 10 cm test piece cut from the lid laminate (1). This was sealed in a vial of specified dimensions, and the vial was heated at a furnace temperature of 110°C and a loop temperature of 115°C to measure the amount of organic solvent generated in the headspace of the vial. The evaluation criteria are shown below.

[0127] Residual solvent content: 5 mg / m² 2 Less than: Low odor, good odor (○) Residual solvent content: 5 mg / m² 2 The above: Poor odor performance (×)

[0128] Tables 1 to 3 show the evaluation results for the lid laminates A1 to A22 and B1 to B18.

[0129] <3. Printing layer durability test of lid laminate (1)>

[0130] This test will be conducted using the sliding device (5) conceptually shown in Figure 4. First, one 10 cm square test piece is prepared from the lid laminate (1). Next, this test piece is placed on the support base (53) with its heat-sealed layer (17) side facing up, and its four sides are secured with adhesive tape. Next, the cotton gauze covering the spherical member (52) of the device (5) is moistened once by spraying it with water using a spray bottle. Then, the support column (51) is lowered, and the spherical member (52) is lightly pressed against the protective layer (11) of the test piece. In this state, the support column (51) is moved left and right at a reciprocating distance of 2 cm / second, and the number of reciprocations until streaking occurs on the surface of the printed layer (12) and the aluminum foil forming the barrier layer (14) is exposed is counted. However, the upper limit is 30 reciprocations. The evaluation criteria are shown below.

[0131] 30~21 times: Good (○) 20-11 times: Fairly good (△) 10~ 1 time: Defective (×)

[0132] Tables 1 to 3 show the evaluation results for the lid laminates A1 to A22 and B1 to B18.

[0133] <4. Heat seal strength test of laminated material for lids> The diagram of the evaluation apparatus for this test is omitted. In this test, first, a strip-shaped test piece (100 mm long × 15 mm wide) is cut from the lid laminate (1). Next, this test piece is superimposed on a polystyrene resin test piece of the same dimensions (100 mm long × 15 mm wide × 0.3 mm thick) with its heat-seal layer (17) side aligned on all four sides. Next, the two test pieces are completely heat-sealed under the conditions of a predetermined temperature (140°C or 160°C), a predetermined pressure (0.2 MPa), and a predetermined time (1 second). After that, the T-shaped peel strength is measured in accordance with JIS K6854-3 under the condition of a tensile speed of 300 mm / min. Then, the heat-seal strength of the lid laminate (1) is evaluated according to the following criteria, depending on the numerical range of tensile strength required for peeling.

[0134] Less than 15N / 15mm: 10N / 15mm or more: Excellent (◎) Less than 20N / 15mm, 15N / 15mm or more: Good (○) Less than 10N / 15mm and 5N / 15mm or more: Fairly good (△) Less than 5N / 15mm: Defective (×)

[0135] Tables 1 to 3 show the evaluation results for the lid laminates A1 to A22 and B1 to B18.

[0136] <5. Making the lid (2)> A small 80mm square piece was cut from the laminated lid material A1, and by deep drawing, a cap-shaped lid A1 with a circular body (40mm in diameter) and a skirt portion was produced. Lids A2 to A22 and lids B1 to B18 of the same dimensions were produced in the same manner using the other laminated lid materials.

[0137] <6. Preparation of the packaging (4), and evaluation of the print layer resistance of the lid (2) in the packaging (4)>

[0138] This test is conducted using a shaking device (6) conceptually shown in Figure 5(a). First, 54cc of water is placed as the contents (C) in a cup-shaped container (3) made of polystyrene resin with a flange of predetermined dimensions (mouth diameter 66mmφ, bottom diameter 57mmφ, height 26mm, flange width 7mm). Lid A1 is then placed over the opening from the heat-seal layer side, and a stainless steel plate heated to 150°C is pressed from above lid A1 for 1.0 second to create a sealed package A1. Packages A2 to A22 and packages B1 to B18 are created in the same manner for the other lids.

[0139] Next, two packages A1 were placed side by side on a horizontal table, with their flanges touching, and a polyethylene binding film (63) was wrapped around them from the sides to bind them together, creating one set of samples (62). Eleven more sets of samples (62) were made in the same manner. Next, three sets of samples (62) were placed on the bottom of a cardboard box packaging material (61) (11 cm long x 24 cm wide x 19 cm deep), and a 1 mm thick cardboard sheet (24 cm x 19 cm) was placed on top of them as a partition material (64), with three more sets of samples (62) placed on top of that. This process was repeated two more times, resulting in a total of 12 sets of samples (62) being stacked. Next, the packaging material (61) was wrapped with adhesive tape and then subjected to a commercially available shaking device (Yamato Scientific Co., Ltd., SA31) and shaken for 100 hours under specified conditions (120 rpm, amplitude 50 mm). Then, the packaging material (61) was unpacked, and the top surface of the lid A1 of all 24 packages A1 was visually inspected, and the number of peeled-off sections of the printed layer (12) was counted for each package. The same test was performed on packages A2 to A22 and packages B1 to B18.

[0140] 0~2 pieces: Good (○) 3-10 items: Fairly good (△) 14~15 pieces: Defective (×)

[0141] Furthermore, the print layer resistance in this test is a direct evaluation that assumes friction and impact applied to the protective layer (11) of the lid (2) on the packaging (4) during transportation of the packaging (4), and is therefore in line with actual conditions.

[0142] <7. Preparation of the packaging (4), and evaluation of the internal pressure crack resistance of the lid (2) of the packaging (4)> This test is conducted using a shaking device (7) conceptually shown in Figure 5(b). First, a cylindrical polystyrene container (3) with an opening (outer diameter of opening 40 mm, inner diameter of opening 36 mm, height 80 mm) has a lid A1 placed over the periphery (width 2 mm) of the opening. A commercially available high-frequency induction heating sealing device (model BMD-1S, manufactured by BME Corporation) is used to perform high-frequency sealing under predetermined sealing conditions (output 850, pressure 0.05 MPa, 1.4 seconds) to produce a package A1 without contents (C). Packages A2 to A22 and B1 to B18 are produced in the same manner for lids A2 to A22 and lids B1 to B18.

[0143] Next, package A1 was placed in a shaking device (7), and the containment section (71) was vibrated 120 times per minute, repeatedly impacting a pair of contact members (73) provided on the inner surface of the side wall section (72). After shaking 10,000 times, the presence or absence of cracks in the aluminum foil forming the barrier layer (14) of the lid A1 was observed. Packages A2 to A22 and packaged B1 to B18, which did not contain contents (C), were evaluated in the same manner.

[0144] No cracks after 10,000 shaking cycles: Excellent (◎) Crack formation after 9000 to 10000 shaking cycles: Good (〇) Cracks occurred after fewer than 9000 shaking cycles: Defective (×)

[0145] Furthermore, the internal pressure crack resistance in this test is a direct evaluation that assumes the cyclic fatigue accumulated in the barrier layer (14) of the lid (2) on the packaging (4) during transportation of the packaging (4), and is therefore in line with actual conditions.

[0146] (Explanation of symbols in the table) NC: Nitrocellulose, VCVA: Vinyl chloride-vinyl acetate copolymer, PEs: Thermoplastic polyester Tel, CP: Cellulose propionate, PE-C: Chlorinated polyethylene, BC: Benzyl cellulose, PMMA: Polymethyl methacrylate.

[0147] [Table 1]

[0148] [Table 2]

[0149] [Table 3]

[0150] (Consideration of residual amount of organic solvent) The laminated lid materials used in both the examples and comparative examples did not present any problems in terms of odor.

[0151] (Consideration of the print layer resistance of the laminate material for the lid (1)) In all of the lid laminates in Examples 1 to 14, the glass transition temperature and melting point of the thermoplastic resin forming the protective layer were higher than those of the thermoplastic resin forming the printing layer, and also higher than those of the thermoplastic resin forming the undercoat layer, resulting in good (○) or somewhat good (△) resistance to the printing layer. In particular, the lid laminates in Examples 1 to 4, Examples 7 to 8, and Examples 11 to 14 are considered to have particularly excellent resistance to the printing layer because the thermoplastic resin used for the printing layer and the undercoat layer is the same. On the other hand, the laminated lid materials of Comparative Examples 1 to 10 did not exhibit the same relationship between glass transition temperature and melting point as those found in the laminated lid materials of Examples 1 to 14, resulting in poor print layer resistance (×). This trend was also observed in the laminated lid materials of Examples 15 to 22 and Comparative Examples 11 to 18.

[0152] (Consideration of heat seal strength) The laminated lid materials of Examples 1 to 14 exhibited excellent heat seal strength (◎) at both 140°C and 160°C, as the bottommost heat seal layer was composed of a heat-fusible resin film. On the other hand, the laminated lid materials of Examples 15 to 22, while not problematic in practical use, exhibited relatively lower heat seal strength because the heat seal layer was composed of a hot-melt adhesive. This trend was also observed in the laminated lid materials of Comparative Examples 1 to 18.

[0153] (Consideration of the print layer resistance of the lid (2) in the packaging (4)) In all of the lids according to Examples 1 to 14, the glass transition temperature and melting point of the thermoplastic resin forming the protective layer were higher than those of the thermoplastic resin forming the printing layer, and also higher than those of the thermoplastic resin forming the undercoat layer. Therefore, even when subjected to a predetermined shaking test while heat-sealed to the packaging, the print layer resistance was good (○) or somewhat good (△). In particular, the lid laminates of Examples 1 to 4, Examples 7 to 8, and Examples 11 to 14 are considered to have particularly excellent print layer resistance because the thermoplastic resin used for the printing layer and the undercoat layer is the same. On the other hand, the lid laminates of Comparative Examples 1 to 10 did not have the same relationship between glass transition temperature and melting point as the lid laminates of Examples 1 to 14, resulting in poor print layer resistance (×). The above trends were also observed in the lid laminates of Examples 15 to 22 and Comparative Examples 11 to 18.

[0154] (Consideration of the internal pressure crack resistance of the lid (2) in the packaging (4)) The laminated lid materials of Examples 1 to 14 had a heat-seal layer composed of a heat-fusible resin film at the bottom, resulting in excellent resistance to internal pressure cracking (◎) when the lids were heat-sealed to the packaging. On the other hand, the laminated lid materials of Examples 15 to 22 had a heat-seal layer composed of a hot-melt adhesive, resulting in only slightly better resistance to internal pressure cracking (○), although there were no practical problems. The same trend was observed for the laminated lid materials of Comparative Examples 1 to 18. [Explanation of Symbols]

[0155] (1) Laminate material for lid: (11) Protective layer, (12) Printed layer, (13) Primer layer, (14) Barrier layer, (15) Inner primer layer, (16) Buffer layer, (17) Heat seal layer, (17a) Base layer, (17b) Heat seal layer, (18) Embossed pattern, (18a) Protrusions, (18b) Spacing, (18c) Base surface (2) Lid: (2a) Main body, (2b) Skirt (3) Container: (31) Peripheral edge of opening (C)Contents (4) Packaging (5) Sliding device, (6) Vibrating device, (7) Vibrating device (D1) Laminated material for the lid (1) and the outside of the lid (2) (D2) Laminated material for the lid (1) and inside of the lid (2)

Claims

1. A lid laminate for producing a lid that can be heat-sealed to a peripheral portion of an opening of a container that contains contents, Starting from the outside, a protective layer made of an overcoat agent containing a thermoplastic resin and an organic solvent; a printing layer made of a printing ink containing a thermoplastic resin, an organic solvent, and a colorant; a primer layer made of an anchor coating agent containing a thermoplastic resin and an organic solvent; a barrier layer made of a metal foil; a heat seal layer made of a heat-fusible resin; and the glass transition temperature of the thermoplastic resin constituting the printing layer and the glass transition temperature of the thermoplastic resin constituting the primer layer are both lower than the glass transition temperature of the thermoplastic resin constituting the protective layer; Laminated material for lid.

2. The lid laminate of claim 1, characterized in that the thermoplastic resin constituting the protective layer has a glass transition temperature of 100°C or higher, the thermoplastic resin constituting the printing layer has a glass transition temperature of less than 100°C, and the thermoplastic resin constituting the primer layer has a glass transition temperature of less than 100°C.

3. The lid laminate of claim 1, characterized in that the melting points of the thermoplastic resin forming the printing layer and the thermoplastic resin forming the primer layer are both lower than the melting point of the thermoplastic resin forming the protective layer.

4. The lid laminate of claim 1, characterized in that the melting point of the thermoplastic resin constituting the protective layer is 130°C or higher, the melting point of the thermoplastic resin constituting the printing layer is less than 130°C, and the melting point of the thermoplastic resin constituting the primer layer is less than 130°C.

5. The lid laminate of claim 1, characterized in that, when the total thickness of the protective layer, the printing layer, and the primer layer is taken as 1, the thickness ratio of the protective layer is 34% to 85%, the thickness ratio of the printing layer is 7% to 33%, and the thickness ratio of the primer layer is 8% to 33%.

6. 2. The lid laminate according to claim 1, wherein the thermoplastic resin forming the print layer and the thermoplastic resin forming the primer layer are the same or of the same type.

7. the thermoplastic resin forming the protective layer is a cellulose-based thermoplastic resin; 2. The lid laminate according to claim 1, wherein the thermoplastic resin forming the printing layer is a synthetic resin-based thermoplastic resin, and the thermoplastic resin forming the undercoat layer is a synthetic resin-based thermoplastic resin.

8. 2. The lid laminate according to claim 1, wherein an inner primer layer made of an anchor coating agent and / or a buffer layer made of a synthetic resin are interposed between the barrier layer and the heat seal layer.

9. 2. The lidding laminate of claim 1, wherein the heat seal layer comprises a hot melt adhesive.

10. 2. The lid laminate according to claim 1, wherein the heat seal layer comprises, from the outside, a base layer made of a synthetic resin and a heat seal layer made of a heat-fusible resin film.

11. 2. The lid laminate according to claim 1, wherein an embossed pattern consisting of a plurality of independent protrusions is formed over the entire innermost surface of the heat seal layer.

12. The residual amount of organic solvent measured by the standard gas chromatography test method in accordance with the Control Equipment Manual for the Manufacturing of Flexible Packaging Materials, edited by the Flexible Packaging Hygiene Council, is 5 mg / m 2 2. The lid laminate of claim 1, wherein the lid laminate has a thickness of less than 1 / 2 mm.

13. A lid, characterized in that it is made of the laminated material for lids according to any one of claims 1 to 12.

14. A package obtained by heat-sealing the lid of claim 13 to the periphery of the opening of a container containing contents so as to cover the opening.

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