Composite film, lid material, and lidded container containing contents

Abstract

To provide a composite film capable of suppressing remaining of a film formed by an adhesive layer and a heat seal layer in a resealed part even in unsealing under a low-temperature environment when a package heat-sealed to be resealable is formed, a lid material formed from the composite film, and a content-stored container with a lid.SOLUTION: A composite film 10 comprises a base material layer, an adhesive layer 4, and a heat seal layer 5 in this order. The base material layer and the heat seal layer are bonded to each other via the adhesive layer. The adhesive layer includes a thermoplastic elastomer and a rosin ester, and the heat seal layer includes a polyethylene resin.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a composite film, a lid material, and a lidded container containing a content. [Background technology]

[0002] Conventionally, various types of resealable packaging have been used as packaging means for foods, medicines, etc. that cannot be consumed in one go. For such packaging, a sealing method using a multilayer film has been proposed, which can impart a resealable function to the packaging itself without attaching an accessory such as a zipper.

[0003] As an example of a resealable multilayer film, a laminate has been disclosed in which a surface resin layer (A) mainly composed of a thermoplastic resin (a), an adhesive resin layer (B) mainly composed of a styrene-based thermoplastic elastomer (b) having specific physical properties, and a heat-sealable resin layer (C) mainly composed of an olefin-based resin (c) are laminated in the order (A) / (B) / (C) (see Patent Document 1).

[0004] A package in which the multilayer film described in Patent Document 1 is heat-sealed to a container body or the like can be opened and resealed without any problems.

[0005] Here, the mechanism by which a package that has been heat-sealed to a container body can be opened and resealed is due to the adhesive resin layer (B) and the heat-seal resin layer (C) breaking at both edges of the part that is heat-sealed to the container body, etc. (hereinafter, this may be referred to as "edge tearing").

[0006] Using a package in which a lid is heat-sealed to a container body as an example, the mechanism by which it can be opened and resealed will be explained with reference to FIG.

[0007] Figure 2 is a diagram showing a lidded container 300 containing contents formed using the lid material 100. When opening the lidded container 300 containing contents, as shown in Figure 2(a), by pinching the tab 110 protruding from the flange portion 202 and pulling up the lid material 100, the adhesive layer 104 and the heat seal layer 106 are broken (outer edge cut) at a position corresponding to the outer periphery of the joint portion 202a, and a first break portion 120a corresponding to this position is exposed.

[0008] When the lid member 100 is further pulled up, as shown in Figure 2(b), the lid member 100 undergoes delamination at the interface between the base layer 102 and the adhesive layer 104. Thereafter, when the delamination reaches a position corresponding to the inner periphery of the joint portion 202a, the adhesive layer 104 and the heat seal layer 106 rupture (inner edge tearing) as shown in Figure 2(c), exposing a second rupture portion 120b corresponding to this position, and forming a reseal portion 104a in the flange portion 202 of the container body 200.

[0009] In other words, the resealable portion 104a is a laminate consisting of an adhesive layer 104 and a heat seal layer 106 that is cut out from the lid material 100 by outer edge cutting, interlayer peeling, and inner edge cutting in the area of ​​the joint 202a formed in the flange portion 202, with the adhesive layer 104 exposed on the surface.

[0010] When resealing the opened lidded container 300 containing the contents, the lid material 100 is pressed against the resealing portion 104a, causing the base material layer 102 and the adhesive layer 104 to come into close contact with each other and reseal the container. [Prior art documents] [Patent documents]

[0011] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-125820 Summary of the Invention [Problem to be solved by the invention]

[0012] In the package described in Patent Document 1, in which the multilayer film is heat-sealed, the inner edge tearing described above may be difficult in a low-temperature environment. Therefore, when opening the package in a low-temperature environment, the resealable portion may not be cut off by the inner edge tearing, and a film consisting of the adhesive layer and the heat-sealing layer may remain on the container flange.

[0013] The present invention has been made in view of the above background, and aims to provide a composite film, a lid material formed from the composite film, and a lidded container containing contents, which, when heat-sealed to form a resealable package, can prevent a film consisting of an adhesive layer and a heat-sealing layer from remaining in the resealable portion even when the package is opened in a low-temperature environment. [Means for solving the problem]

[0014] The present inventors have conducted extensive research to solve the above problems, and have found that if a composite film for forming a heat-sealable resealable package is a laminate of specific materials and a specific laminate structure, it is possible to easily tear the inner edge even when the package is opened in a low-temperature environment, and to prevent the film consisting of the adhesive layer and the heat-sealable layer from remaining in the resealable portion, thereby completing the present invention.

[0015] <<Aspect 1>> The film comprises a base layer, an adhesive layer, and a heat seal layer in this order; the base material layer and the heat seal layer are bonded to each other by the adhesive layer, The adhesive layer contains a thermoplastic elastomer and a rosin ester, and The heat seal layer contains a polyethylene resin. Composite film. <<Aspect 2>> 2. The composite film of claim 1, wherein the thermoplastic elastomer is a styrene-based thermoplastic elastomer. Aspect 3 3. The composite film of claim 1 or 2, wherein the thermoplastic elastomer is a styrene-butadiene-butylene-styrene copolymer. Aspect 4 The composite film according to any one of aspects 1 to 3, wherein the adhesive layer has a thickness of 5 μm or less. Aspect 5 The heat seal layer has a density of 0.920 to 0.958 g / cm 3 The composite film according to any one of aspects 1 to 4, wherein the polyethylene resin layer is Aspect 6 6. The composite film of claim 5, wherein the polyethylene resin layer comprises only high density polyethylene or high density polyethylene and low density polyethylene. Aspect 7 Aspect 7. The composite film according to aspect 6, wherein the content of the high-density polyethylene is 50% by mass or more based on the total mass of the heat seal layer. Aspect 8 A lid material formed from the composite film according to any one of the first to seventh embodiments. Aspect 9 9. The lid material of embodiment 8, which is resealable. Aspect 10 A lid material according to aspect 8 or 9, which does not have a half cut on the heat seal layer side. Aspect 11 a container body having a storage portion and a flange portion; Contents contained in the container body; A lid material formed from the composite film according to any one of aspects 1 to 7; Equipped with the heat seal layer is heat sealed to the flange portion to form a resealable joint; A container with a lid containing the contents. Aspect 12 The container body is a paper cup, A lidded container containing contents according to aspect 11, wherein the flange portion is coated with a polyethylene resin. [Effects of the Invention]

[0016] According to the composite film of the present invention, a resealable package is formed by heat-sealing the heat-seal layer to a container body or the like, and when the package is opened, even in a low-temperature environment, it is possible to prevent the film consisting of the adhesive layer and the heat-seal layer from remaining in the resealable portion.

[0017] Furthermore, a package formed by heat-sealing the heat-seal layer of the composite film of the present invention to a container body or the like can be opened by breaking the heat-seal layer at both the outer and inner edges of the heat-sealed joint, so there is no need to make a cut (half cut) on the surface of the heat-seal layer side of the composite film to be used for opening.

[0018] Therefore, there is no need to make a half cut along the area intended to be heat-sealed to the container, for example, the area to be heat-sealed to the flange portion of the container body, nor is there any need for alignment operations during heat-sealing, which contributes to the productivity of composite films, lid materials, and lidded containers. [Brief explanation of the drawings]

[0019] [Figure 1] 1 is a cross-sectional view of a composite film according to one embodiment of the present invention. [Figure 2] 1 is a diagram showing a peeling mechanism when a lidded container containing contents according to one embodiment of the present invention is opened. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0020] Composite film The composite film of the present invention is a composite film in which at least a base layer, an adhesive layer, and a heat seal layer are laminated in this order, and the base layer and the heat seal layer are bonded to each other by the adhesive layer. The adhesive layer and the heat seal layer are made of specific materials.

[0021] The structure of the composite film of the present invention will be described below with reference to the drawings: Figure 1 shows a cross-sectional view of one embodiment of the composite film of the present invention.

[0022] A composite film 10 according to one embodiment of the composite film of the present invention shown in FIG. 1 comprises a paper layer 1, an aluminum layer 2 laminated on the inside of the paper layer 1, a resin layer 3 laminated on the inside of the aluminum layer 2, an adhesive layer 4 arranged adjacent to the resin layer 3, and a heat seal layer 5 laminated on the inside of the adhesive layer 4.

[0023] In a composite film 10 according to one embodiment of the composite film of the present invention shown in Fig. 1, the substrate layer is a laminate of three layers, specifically, the substrate layer is made up of a paper layer 1, an aluminum layer 2, and a resin layer 3. The composite film 10 shown in Fig. 1 has the substrate layer, an adhesive layer 4, and a heat seal layer 5 laminated in this order.

[0024] The composite film of the present invention may include any layers other than the substrate layer, adhesive layer, and heat seal layer as essential components.

[0025] The thickness of each layer constituting the composite film of the present invention can be appropriately determined depending on the intended use of the composite film.

[0026] <Base material layer> The substrate layer is an essential constituent layer of the composite film of the present invention. The substrate layer is adjacent to the adhesive layer and is bonded to the heat seal layer by the adhesive layer. In the composite film of the present invention, the substrate layer may be a single layer or a laminate consisting of multiple layers.

[0027] In the composite film of the present invention, the base material layer, adhesive layer, and heat seal layer are laminated in this order, and therefore, when a structure such as a package is formed, the base material layer may serve as the outer layer of the structure. In this case, the base material layer can serve as a protective layer when the innermost heat seal layer is heat-sealed to form the structure. The base material layer can also serve as a printing layer on which printing is performed to indicate the contents, etc.

[0028] When the substrate layer is a single layer, the substrate layer may be a resin layer made of resin, particularly a resin that serves as a protective layer and is printable. A commonly used resin can be used as a material for forming the resin layer that serves as the substrate layer, and examples thereof include polyesters such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), and polybutylene terephthalate (PBT), polyolefins such as polyethylene (PE), polypropylene (PP), and polystyrene (PS), polyamides (PA) such as nylon-6 and nylon-66, and polycarbonate (PC).

[0029] The above resins may be used alone or in a blend of two or more, and may contain additives for imparting functionality, etc., as required.

[0030] Among these, from the viewpoint of improving the adhesion between the base layer and the adhesive layer, the resin constituting the base layer is preferably polyester. The polyester resin is not particularly limited, and examples thereof include polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polybutylene terephthalate (PBT), polybutylene naphthalate (PBN), polycyclohexane terephthalate (PCT), polycarbonate (PC), etc.

[0031] Furthermore, polyethylene terephthalate (PET) is particularly preferred in terms of printability, imparting rigidity to the composite film, ease of availability, and ease of handling.

[0032] When the substrate layer is a resin layer, a preformed resin film may be used. The resin film to be the substrate layer may be a film formed from the above-mentioned resins, etc., and may be unstretched or uniaxially or biaxially stretched. Among these, a biaxially stretched film is preferred.

[0033] Furthermore, the resin film serving as the base layer may be subjected to a roughening treatment to roughen its surface. The roughened surface creates an anchor effect with the adjacent adhesive layer, thereby improving adhesion.

[0034] When the substrate layer is a laminate of two or more layers, other layers are provided in addition to the layers in the case of a single layer described above. Examples of other layers include a barrier layer for imparting barrier properties, a reinforcing layer for reinforcing strength, or an adhesive layer for bonding between layers. Furthermore, the substrate layer that becomes a laminate may be provided with two or more layers of the same type.

[0035] (barrier layer) The barrier layer constituting the substrate layer is a layer for imparting barrier properties to the composite film.

[0036] Examples of the barrier layer include a resin layer made of ethylene-vinyl alcohol copolymer (EVOH), nylon (NY), polyvinylidene chloride (PVDC), polyacrylonitrile (PAN), or the like, which exhibits the function of blocking gases such as oxygen and water vapor.

[0037] The above resins may be used alone or in a blend of two or more, and may contain additives for imparting functionality, etc., as required.

[0038] Alternatively, for example, an inorganic vapor deposition film layer, a metal foil layer, an organic coating layer, or the like may be used.

[0039] Examples of inorganic vapor-deposited film layers that can serve as barrier layers include silica vapor-deposited films, aluminum vapor-deposited films, alumina vapor-deposited films, and silica-alumina vapor-deposited films.

[0040] Examples of metal foils that can be used as a barrier layer include metal foils such as aluminum foil, copper foil, and titanium foil, and alloy foils such as aluminum alloy foil and stainless steel foil.

[0041] The organic coating layer that serves as a barrier layer may be a barrier coating layer such as a vinylidene chloride coating layer or a polyvinylidene fluoride coating layer.

[0042] When an inorganic vapor-deposited film layer or an organic coating layer is present as the barrier layer, the thickness of the barrier layer is preferably 100 nm or more, 200 nm or more, 300 nm or more, 500 nm or more, 700 nm or more, or 1 μm or more, from the viewpoint of ensuring strength and barrier properties, and is preferably 5 μm or less, 4 μm or less, 3 μm or less, or 2 μm or less, from the viewpoint of improving handleability when the composite film is used as a packaging material or the like.

[0043] When a metal foil is used as the barrier layer, the thickness of the barrier layer is preferably 5 μm or more, 7 μm or more, 10 μm or more, or 15 μm or more from the viewpoint of ensuring strength and barrier properties, and is preferably 100 μm or less, 80 μm or less, 60 μm or less, 55 μm or less, 50 μm or less, 45 μm or less, 40 μm or less, or 35 μm or less from the viewpoint of improving handleability when the composite film is used as a packaging material or the like.

[0044] (reinforcement layer) The reinforcing layer constituting the base layer is a layer for reinforcing the strength of the composite film. Examples of materials for the reinforcing layer include paper such as coated paper and art paper, synthetic paper, nonwoven fabric, etc. When the paper or the like that forms the reinforcing layer faces the outside of the base layer, its surface may be printed by gravure printing, flexographic printing, etc.

[0045] (adhesive layer) The adhesive layer constituting the base layer is a layer that exists between layers and serves to bond the layers together. Examples of adhesive layers include layers made of ethylene-acrylic acid copolymer (EAA), ethylene-methacrylic acid copolymer (EMAA), and ionomer.

[0046] The adhesive layer may also be a layer made of an adhesive, such as a dry laminating adhesive, a hot melt adhesive, a water-soluble adhesive, an emulsion adhesive, a non-solvent laminating adhesive, or a thermoplastic resin for extrusion laminating.

[0047] <Adhesive layer> The adhesive layer is an essential constituent layer of the composite film of the present invention, and is disposed between the adjacent substrate layer and heat seal layer to bond them together.

[0048] The composite film of the present invention can be heat-sealed to a container body or the like to form a resealable package, and when the package is opened, delamination occurs between the adhesive layer and the base layer adjacent to the adhesive layer.

[0049] In the composite film of the present invention, the adhesive layer contains a thermoplastic elastomer and a rosin ester as essential components. Because the adhesive layer contains a thermoplastic elastomer and a rosin ester, the composite film of the present invention can form a resealable package by heat-sealing the heat-sealable layer, and when the package is opened, delamination occurs between the adhesive layer and the base layer, and the package exhibits good resealability.

[0050] Furthermore, even when the package is opened in a low-temperature environment, the inner edge can be easily torn, and the film consisting of the adhesive layer and the heat seal layer can be prevented from remaining at the resealable portion.

[0051] The adhesive layer can be produced, for example, by preparing a composition containing a thermoplastic elastomer, a rosin ester, and a solvent, and applying the composition to the surface of the layer to be laminated. Examples of solvents that can dissolve both the thermoplastic elastomer and the rosin ester include ethyl acetate. Examples of coating methods include gravure printing, offset printing, flexographic printing, silk printing, and coating with a dry laminator.

[0052] The thickness of the adhesive layer is preferably 5 μm or less, which makes it easier to peel the adhesive layer from the base layer when the heat-sealable layer is heat-sealed to form a resealable package and the package is opened.

[0053] The thickness of the adhesive layer may be 4 μm or less, or 3 μm or less, and is preferably 1 μm or more, 1.5 μm or more, or 2 μm or more from the viewpoint of obtaining sufficient resealability.

[0054] The adhesive layer is 4.0 g / m 2 The adhesive layer is present in the following amount, which is preferable from the viewpoint of achieving good delamination between the adhesive layer and the base layer and good resealability. 2 or less, or 3.5 g / m 2 It may be less than 0.1 g / m 2 More than 0.3g / m 2 or more, or 0.5g / m 2 It may be more than that.

[0055] (thermoplastic elastomer) The thermoplastic elastomer constituting the adhesive layer of the composite film of the present invention is a material that can be fluidized and molded at high temperatures and exhibits rubber elasticity at room temperature. The thermoplastic elastomer that can be used in the present invention is not particularly limited, but examples thereof include olefin-based thermoplastic elastomers and styrene-based thermoplastic elastomers.

[0056] Examples of olefin-based thermoplastic elastomers include ethylene-propylene copolymer (EPM), ethylene-butene copolymer (EBM), ethylene-octene copolymer, ethylene-propylene-butene copolymer, propylene-butene copolymer, and ethylene-propylene-diene copolymer (EPDM).

[0057] It is also possible to use a blend type olefinic thermoplastic elastomer in which an olefinic rubber (EPM, EPDM, etc.) is dispersed in a matrix of an olefinic resin (for example, polypropylene, polyethylene, etc.).

[0058] Examples of styrene-based thermoplastic elastomers include styrene-ethylene-butene copolymer (SEB), styrene-ethylene-propylene copolymer (SEP), styrene-ethylene-butene-styrene copolymer (SEBS), styrene-ethylene-propylene-styrene copolymer (SEPS), styrene-ethylene-ethylene-propylene-styrene copolymer (SEEPS), styrene-butadiene-butylene-styrene copolymer (partially hydrogenated styrene-butadiene-styrene copolymer; SBBS), partially hydrogenated styrene-isoprene-styrene copolymer, and partially hydrogenated styrene-isoprene-butadiene-styrene copolymer.

[0059] The thermoplastic elastomer constituting the adhesive layer of the composite film of the present invention may be one type alone or a combination of two or more types of thermoplastic elastomers.

[0060] The thermoplastic elastomer constituting the adhesive layer of the present invention may be a styrene-based thermoplastic elastomer, since it exhibits rubber elasticity in the normal temperature or high temperature range.

[0061] Furthermore, among styrene-based thermoplastic elastomers, styrene-butadiene-butylene-styrene copolymers may be used because they have good compatibility with tackifiers.

[0062] The content of the thermoplastic elastomer in the adhesive layer may be 30% by mass or more, 35% by mass or more, 40% by mass or more, or 45% by mass or more, and may be 70% by mass or less, 65% by mass or less, 60% by mass or less, or 55% by mass or less, relative to the total mass of the adhesive layer.

[0063] (rosin ester) The rosin ester constituting the adhesive layer of the composite film of the present invention is a compound obtained by esterifying rosin.

[0064] The type of resin acid (various isomers) that is the main component of the rosin to be esterified is not particularly limited, and may be a conjugated resin acid having a conjugated double bond, a non-conjugated resin acid, or a mixture thereof.

[0065] Examples of conjugated resin acids include abietic acid, neoabietic acid, and palustric acid, while examples of non-conjugated resin acids include pimaric acid, isopimaric acid, and dehydroabietic acid.

[0066] The form of the rosin ester is not particularly limited, and may be, for example, an ester of rosin or polymerized rosin with a polyhydric alcohol, an ester of hydrogenated rosin, or a maleic acid-modified rosin ester obtained by adding maleic acid to an ester.

[0067] Commercially available "rosin esters" can be used, such as the Haritack series manufactured by Harima Chemical Industries, Ltd., the Ertelgum series and Pencel (registered trademark) series manufactured by Arakawa Chemical Industries, Ltd.

[0068] The rosin ester content in the adhesive layer may be 30% by mass or more, 35% by mass or more, 40% by mass or more, or 45% by mass or more, and may be 70% by mass or less, 65% by mass or less, 60% by mass or less, or 55% by mass or less, relative to the total mass of the adhesive layer.

[0069] By incorporating a sufficient amount of rosin ester into the adhesive layer, the adhesive properties of the adhesive layer can be improved, and by preventing the amount of rosin ester from becoming excessive, the strength of the adhesive layer can be maintained.

[0070] The rosin ester constituting the adhesive layer of the composite film of the present invention may be one type alone or two or more types of rosin esters may be used in combination.

[0071] (Other ingredients) In addition to the thermoplastic elastomer and rosin ester, which are essential components, the adhesive layer of the composite film of the present invention may contain other resins, additives, etc., to impart functionality, etc., as necessary.

[0072] <Heat seal layer> The heat seal layer is an essential constituent layer of the composite film of the present invention. The heat seal layer is the layer used for heat sealing when forming a package or the like using the composite film of the present invention. For this reason, the heat seal layer is disposed so as to be the innermost layer of the composite film.

[0073] The heat seal layer of the composite film of the present invention contains a polyethylene resin, which allows for thermal adhesion and can impart sufficient seal strength to the resulting structure.

[0074] Examples of the polyethylene resin contained in the heat seal layer include low density polyethylene (LDPE), linear low density polyethylene (LLDPE), medium density polyethylene (MDPE), and high density polyethylene (HDPE).

[0075] When it is desired to impart resistance to contents to the composite film of the present invention, it is preferable to use, for example, low density polyethylene (LDPE), linear low density polyethylene (LLDPE), or the like.

[0076] The heat seal layer may be formed using a preformed film, or may be formed by melting and extruding a material for forming the heat seal layer onto the surface of the target laminate and then cooling and solidifying it.

[0077] The polyethylene resin constituting the heat seal layer may be a single type or a blend of two or more types. Furthermore, the heat seal layer may contain resins other than polyethylene resins, additives, etc., as needed.

[0078] The heat seal layer constituting the composite film of the present invention has a density of 0.920 to 0.958 g / cm 3 According to this configuration, sufficient film-forming properties and heat-sealing properties are provided, and edge tearing can be facilitated.

[0079] In the present invention, the density may be a value measured in accordance with JIS K7112-1999.

[0080] The density of the heat seal layer is 0.923 g / cm 3 More than 0.925g / cm 3 More than 0.927g / cm 3 More than 0.930g / cm 3 More than 0.933g / cm 3 or more, or 0.935 g / cm 3 or more, and 3 Below, 0.950g / cm 3 or less, or 0.948 g / cm 3 It may be the following:

[0081] In the composite film of the present invention, the heat seal layer preferably contains only high-density polyethylene or a mixture of high-density polyethylene and low-density polyethylene. A layer made of only high-density polyethylene or a mixed resin containing high-density polyethylene and low-density polyethylene can improve the film formability and edge cutting properties of the heat seal layer.

[0082] Whether the heat seal layer is a layer made of a mixed resin containing high-density polyethylene and low-density polyethylene can be confirmed, for example, by using a differential scanning calorimeter (DSC) to compare the curve measured for the heat seal layer with the curve measured for each polyethylene that makes up the mixed resin layer.

[0083] In addition, when the polyethylene resin layer contained in the heat seal layer is a mixed resin layer containing high-density polyethylene and low-density polyethylene, the above density may be a weighted average in which the density of each component is weighted by the content of each component.

[0084] The thickness of the heat seal layer is not particularly limited and may be, for example, 1 μm or more, 2 μm or more, or 3 μm or more. From the viewpoint of easier edge cutting, the thickness is preferably less than 10 μm, 7 μm or less, 6 μm or less, or 5 μm or less.

[0085] (high density polyethylene) In this specification, high-density polyethylene refers to polyethylene containing 80 mol % or more, 90 mol % or more, 95 mol % or more, or 98 mol % or more of repeating units of methylene groups, including the difference in branching if any, or substantially all of the repeating units are methylene groups, and having a density of 0.942 g / cm 3 This refers to the above polyethylene.

[0086] In particular, 0.942 g / cm 3 More than 0.945g / cm 3 More than 0.948g / cm 3 More than 0.950g / cm 3 More than 0.952g / cm 3 or more, or 0.955 g / cm 3 The polyolefin resin has a density of or above 1000 kJ / cm2, is substantially free of long-chain branched structures, and is obtained by radical polymerization of ethylene by a low-pressure method.

[0087] The density of high density polyethylene is 0.970 g / cm 3 Below, 0.967g / cm 3Below, 0.965g / cm 3 Below, 0.962g / cm 3 or less, or 0.960 g / cm 3 It may be the following:

[0088] The thermal properties of the preferred high-density polyethylene are not particularly limited, but for example, when measured in accordance with JIS K6922-1 and -2 and JIS K7210-1 under conditions of a temperature of 190°C and a load of 21.18 N, the melt mass-flow rate is preferably 0.1 g / 10 min or more, 0.5 g / 10 min or more, 1.0 g or more, 3.0 g / 10 min or more, or 5.0 g / 10 min or more, and 100 g / 10 min or less, 50 g / 10 min or less, 30 g / 10 min or less, or 20 g / 10 min or less.

[0089] The content of high-density polyethylene in the heat seal layer is preferably 50 to 100% by mass based on the total mass of the heat seal layer.

[0090] Furthermore, the content of high-density polyethylene may be 60% by mass or more, 70% by mass or more, 80% by mass or more, 90% by mass or more, or 95% by mass or more, and may be 95% by mass or less, 90% by mass or less, 85% by mass or less, 80% by mass or less, or 75% by mass or less, based on the total mass of the heat seal layer.

[0091] (low density polyethylene) In this specification, low-density polyethylene (LDPE) refers to polyethylene having a density of 0.930 g / cm3 or less, which contains 80 mol% or more, 90 mol% or more, 95 mol% or more, or 98 mol% or more of repeating units of methylene groups, including branched chains, or in which substantially all repeating units are methylene groups. 3 This refers to polyethylene less than 100%.

[0092] The density of low-density polyethylene is 0.925 g / cm 3 or less, or 0.923 g / cm 3 It may be less than 0.870 g / cm 3More than 0.875g / cm 3 More than 0.880g / cm 3 More than 0.900g / cm 3 More than 0.910g / cm 3 or more, or 0.915 g / cm 3 It may be more than that.

[0093] The low-density polyethylene may be a so-called linear low-density polyethylene (LLDPE), or may have a long-chain or short-chain branched structure. The short-chain branched structure may be a branched structure derived from an α-olefin having 4 to 18, 4 to 10, or 4 to 8 carbon atoms, such as 1-butene, 1-hexene, 4-methylpentene-1, or 1-octene.

[0094] The thermal properties of the preferred low-density polyethylene are not particularly limited, but for example, when measured in accordance with JIS K6922-1 and -2 and JIS K7210-1 under conditions of a temperature of 190°C and a load of 21.18 N, the melt mass-flow rate is preferably 0.1 g / 10 min or more, 0.5 g / 10 min or more, 1.0 g or more, 3.0 g / 10 min or more, or 5.0 g / 10 min or more, and 100 g / 10 min or less, 50 g / 10 min or less, 30 g / 10 min or less, or 20 g / 10 min or less.

[0095] The content of low-density polyethylene in the heat seal layer is not particularly limited, but may be, for example, 5% by mass or more, 10% by mass or more, 15% by mass or more, 20% by mass or more, or 25% by mass or more, and 50% by mass or less, 45% by mass or less, 40% by mass or less, 35% by mass or less, or 30% by mass or less, relative to the total mass of the heat seal layer.

[0096] <Other layers> The composite film of the present invention may contain layers other than these, as long as it comprises a base layer, an adhesive layer, and a heat seal layer in this order, and the base layer and the heat seal layer are adhered to each other by the adhesive layer.

[0097] <<Method for manufacturing composite film>> The method for producing the composite film of the present invention is not particularly limited, and any known method can be applied, such as dry lamination, hot melt lamination, extrusion lamination, and sandwich lamination.

[0098] <<Applications of composite film>> The structure formed using the composite film of the present invention is not particularly limited.

[0099] <Packaging bag> The structure formed using the composite film of the present invention may be a packaging bag. For example, by heat-sealing the heat-sealable layers of the composite film of the present invention to each other, a three-side sealed bag, a four-side sealed bag, a gusseted packaging bag, a pillow packaging bag, etc. can be formed.

[0100] <Lid material> The structure formed using the composite film of the present invention may be a lid. The lid formed from the composite film of the present invention can be, for example, a lid for sealing the upper opening of a container body. Furthermore, since the lid formed from the composite film of the present invention is a resealable lid, a resealable lidded packaging container can be formed.

[0101] The lid material formed from the composite film of the present invention is, for example, heat-sealed to the upper opening of a container body to form a lidded packaging container, and when the packaging container is opened, the adhesive layer is exposed in a resealable state with the base layer due to outer edge tearing, interlayer delamination between the adhesive layer and base layer constituting the lid material, and inner edge tearing, and when the packaging container is resealed, it is resealed between the adhesive layer and the base layer.

[0102] <Container with lid containing contents> The structure formed using the composite film of the present invention may be a lidded container containing a content.

[0103] Specifically, the present invention relates to a lidded container containing contents, which comprises a container body having a storage section and a flange section, contents contained in the container body, and a lid material formed from the composite film of the present invention, and the heat-seal layer of the lid material is heat-sealed to the flange section of the container body to form a resealable joint.

[0104] A lidded container containing a content formed using a lid material formed from the composite film of the present invention has a resealable joint where the lid material is heat sealed.

[0105] The mechanism for opening and resealing the lidded container is as described above.

[0106] [Configuration of the lidded container with contents] The lidded container containing the contents comprises a container body, the contents, and a lid formed from the composite film of the present invention. (Container body) The container body for forming a lidded container containing contents has a storage portion and a flange portion.

[0107] The material of the container body is not particularly limited as long as it can be heat-sealed by the heat-seal layer of the lid material formed from the composite film of the present invention. Examples include paper containers with a resin-coated surface, and resin containers.

[0108] {Storage section} The storage section is the portion in which the contents are stored. The shape of this portion is not particularly limited, and may be, for example, a substantially truncated cone, a truncated polygonal pyramid, a rectangular parallelepiped, a cubic shape, or the like.

[0109] {Flange part} The flange is a peripheral portion of the upper opening of the storage section of the container body. Its shape is not particularly limited and may be, for example, a brim-like shape. The outer shape of the flange can be appropriately selected depending on the shape of the lid.

[0110] Among these, it is preferable that at least the flange portion of the container is coated with a polyethylene-based resin.Furthermore, it is preferable that the container body is a paper cup and the flange portion is coated with a polyethylene-based resin.

[0111] If the container body is a paper cup having a flange portion coated with polyethylene resin, it is possible to obtain a certain level of seal strength between the heat seal layer of the lid material formed from the composite film of the present invention and smoothly peel the layers at the interface between the adhesive layer and the base material layer.

[0112] (Contents) The contents are contained in the storage section, and are not particularly limited, but examples thereof include heated foods such as soup, instant noodles, chilled foods, and frozen foods, as well as non-heated foods such as snacks and gummy candies. [Example]

[0113] The present invention will be specifically explained with reference to examples and comparative examples, but the present invention is not limited to these.

[0114] <Material> In the examples and comparative examples, the following materials were prepared as materials for constituting the layers.

[0115] (1)Paper layer Paper (NM Art, Nippon Paper Industries Co., Ltd., basis weight: 79.1 g / m 2 )

[0116] (2) Aluminum layer Aluminum foil (1N30, manufactured by UACJ Corporation, thickness: 7 μm)

[0117] (3) Resin layer PET film (PETB, Unitika Ltd., thickness: 12 μm)

[0118] (4) Adhesive layer Thermoplastic elastomer Styrene-butadiene-butylene-styrene copolymer: SBBS (N515, Asahi Kasei Corporation) Rosin ester (Ester Gum AA-G, Arakawa Chemical Industries, Ltd.) Polyterpene (Sylvares® TRB115, Kraton)

[0119] (5) Heat seal layer LDPE (Suntech® LD L2340, Asahi Kasei Corporation, density: 0.923 g / cm 3 ) HDPE (Nipolon Hard (registered trademark) LW13D, Tosoh Corporation, density: 0.956 g / cm 3 ) HDPE (Novatec® HD HJ490, Japan Polyethylene Co., Ltd., density: 0.958 g / cm 3 )

[0120] Examples 1 and 2 <Preparation of composite film> Using the materials shown in Table 1, a composite film having a laminate structure of (paper layer / / aluminum layer / / resin layer / adhesive layer / heat seal layer) was produced by the method described below. In the produced composite film, the substrate layer is a laminate consisting of three layers, that is, the substrate layer is a laminate consisting of paper layer / / aluminum layer / / resin layer. The composite film has a configuration in which the substrate layer, adhesive layer, and heat seal layer are laminated in this order. The parts bonded by dry lamination are indicated by " / / ". Furthermore, the composition (mass %) of the adhesive layer indicates the solid content of each component relative to the entire adhesive layer.

[0121] 1. An aluminum foil (to be used as the aluminum layer) and a polyester film (to be used as the resin layer) were dry laminated together to produce a (resin layer / PET film) laminate. A two-component curing dry lamination adhesive (Takelac A525 / Takenate A52, Mitsui Chemicals, Inc.) was used as the dry lamination adhesive.

[0122] 2. A paper layer was attached to the aluminum layer side by dry lamination to create a laminate (paper / aluminum layer / PET film). A two-component dry lamination adhesive (Takelac A525 / Takenate A52, Mitsui Chemicals, Inc.) was used as the dry lamination adhesive.

[0123] 3. On the PET film side, a mixed resin of thermoplastic elastomer and rosin ester, thermoplastic elastomer only, or a mixed resin of thermoplastic elastomer and polyterpene is applied at a dry weight of 3 g / m to form the adhesive layer. 2 The adhesive layer was coated to a thickness of 3 μm to produce a laminate of (paper / / aluminum layer / / resin layer / adhesive layer). The types and mixing ratios of the adhesive layer are shown in Table 1.

[0124] 4. A polyethylene mixed resin or polyethylene resin, which will become the heat seal layer, was extrusion laminated onto the adhesive layer to a thickness of 5 μm to obtain a composite film with a structure of (paper / / aluminum layer / / resin layer / adhesive layer / heat seal layer). The type of polyethylene resin used in the heat seal layer and the proportion of that resin in the heat seal layer are as shown in Table 1.

[0125] <Creating the lid material> The resulting composite film was cut into a size of φ101 mm with a tab to prepare a lid material.

[0126] <Making a container with a lid> The obtained lid material was heat-sealed to a PE-coated paper cup (flange width: 3 mm, opening inner diameter: 90 mm) using a heated heat seal bar under conditions of a heat seal width of 3 mm, a pressure of 65 MPa, and a time of 0.7 seconds to produce a lidded container.

[0127] 《Reference example 1》 As shown in Table 1, a composite film was prepared in the same manner as in Example 2, except that a mixed resin of styrene-butadiene-butylene-styrene copolymer (SBBS) and polyterpene was used as the material for forming the adhesive layer. The resulting composite film was then used to prepare a lidded container.

[0128] Comparative Example 1 Without using rosin ester, only thermoplastic elastomer was used, at a dry weight of 4 g / m 2 A composite film was produced in the same manner as in Example 1, except that the composition of the heat seal layer was changed as shown in Table 1 and the thickness was changed to 10 μm, and the resulting composite film was used to produce a lidded container.

[0129] Comparative Example 2 Thermoplastic elastomer alone was applied twice to a dry weight of 10 g / m 2 A composite film was produced in the same manner as in Comparative Example 1, except that an adhesive layer having a thickness of 10 μm was formed, and a container with a lid was produced using the resulting composite film.

[0130] "evaluation"

[0131] (Resealing test after supplying hot water) The lidded containers produced in Examples 1 and 2, Reference Example 1, and Comparative Examples 1 and 2 were opened about one-third, then 90°C hot water was poured into them, and they were resealed with finger pressure. After resealing, the lids were evaluated for sealing for 5 minutes. The results are shown in Table 1. 〇: Sealed for 5 minutes ×: The lid opened within 5 minutes

[0132] (Opening test in a low temperature environment) The lidded containers produced in Examples 1 and 2, Reference Example 1, and Comparative Examples 1 and 2 were subjected to opening tests in environments of 0°C, -10°C, and -20°C, and evaluated according to the following criteria. ○: No film remains and the inner edge is cut △: No film remains, but stringiness occurs ×: Film remains

[0133] [Table 1] [Explanation of symbols]

[0134] 1 paper layer 2 aluminum layers 3 Resin layer 4 Adhesive layer 5 Heat seal layer 10 Composite Film 100 Lid material 102 Base material layer 104 Adhesive layer 106 Heat seal layer 104a Re-sealing section 110 tabs 120a first break 120b second break 200 container body 202 flange 202a Joint 250 Contents 300 Lidded container with contents

Claims

1. The film comprises a base layer, an adhesive layer, and a heat seal layer in this order; the base material layer and the heat seal layer are bonded to each other by the adhesive layer, the adhesive layer contains a thermoplastic elastomer and a rosin ester, The thermoplastic elastomer is a styrene-butadiene-butylene-styrene copolymer; and The heat seal layer contains a polyethylene resin. Composite film.

2. The film comprises a base layer, an adhesive layer, and a heat seal layer in this order; the base material layer and the heat seal layer are bonded to each other by the adhesive layer, the adhesive layer contains a thermoplastic elastomer and a rosin ester, the heat seal layer contains a polyethylene resin, the heat seal layer is a polyethylene resin layer having a density of 0.920 to 0.958 g / cm 3 , and The polyethylene resin layer contains only high-density polyethylene or high-density polyethylene and low-density polyethylene. Composite film.

3. The composite film according to claim 2, wherein the content of the high-density polyethylene is 50 to 90% by mass based on the total mass of the heat seal layer.

4. The composite film according to any one of claims 1 to 3, wherein the adhesive layer has a thickness of 5 µm or less.

5. A lid material formed from a composite film including a base layer, an adhesive layer, and a heat seal layer in this order, the base material layer and the heat seal layer are bonded to each other by the adhesive layer, The adhesive layer contains a thermoplastic elastomer and a rosin ester, and The heat seal layer contains a polyethylene resin. Lid material.

6. The lid material according to claim 5, which is resealable.

7. The lid material according to claim 5 or 6, which has no half cut on the heat seal layer side.

8. a container body having a storage portion and a flange portion; Contents contained in the container body; a lid material formed from a composite film including a base layer, an adhesive layer, and a heat seal layer in this order; Equipped with the heat seal layer is heat sealed to the flange portion to form a resealable joint; the base material layer and the heat seal layer are bonded to each other by the adhesive layer, The adhesive layer contains a thermoplastic elastomer and a rosin ester, and The heat seal layer contains a polyethylene resin. A container with a lid containing the contents.

9. The container body is a paper cup, 9. The lidded container containing contents according to claim 8, wherein the flange portion is coated with a polyethylene resin.

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