Laminated film and packaging material

Abstract

To provide a laminated film formed by laminating a plurality of resin layers, the laminated film being capable of suppressing rupture of a package when a food product containing a liquid is packaged using the laminated film to produce the package, and the package is heat-treated with hot water.SOLUTION: A laminated film 1 for producing a package in which a food containing a liquid is packaged and for heat-treating the package, wherein the laminated film 1 includes an inner layer 11, an adhesive layer 13, and a functional layer 12, the inner layer 11 and the functional layer 12 being bonded to each other by the adhesive layer 13, the inner layer 11 containing polyethylene, the functional layer 12 containing either one or both of polyamide and ethylene-vinyl alcohol copolymer, the adhesive layer 13 containing an adhesive resin, and the adhesive resin having a Vicat softening temperature of 90°C or more.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a laminate film and a packaging material. [Background technology]

[0002] As a film for packaging food, a laminated film formed by laminating a plurality of resin layers is widely used. The reason why such a laminated film is used is that a resin film for packaging food is required to have a plurality of properties, such as the ability to be heat sealed with other resin films and the ability to maintain sufficient strength, when packaging food, and these properties are realized by sharing them among different layers.

[0003] On the other hand, food packages are sterilized after production and distributed to consumers through the market, who usually heat the food in hot water before eating it. In recent years, high-quality food packaged in this way has become inexpensive and easy to obtain, and the market size is expanding year by year. Laminated films for use in such packages have been developed (see Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2022-084395 A Summary of the Invention [Problem to be solved by the invention]

[0005] On the other hand, there is a demand to be able to heat-treat packages obtained by packaging foods containing liquids in boiling water at higher temperatures and for longer periods of time than before, and there is a demand for laminated films that can produce packages that will not break even when subjected to such heat treatment.

[0006] The present invention has an object to provide a laminated film formed by stacking a plurality of resin layers, which is capable of suppressing breakage of the package when the package is produced by packaging a food product containing a liquid using the laminated film and heat-treating the package with hot water. [Means for solving the problem]

[0007] In order to solve the above problems, the present invention employs the following configuration. [1] A laminated film for producing a package in which a food containing a liquid is packaged and for heat-treating the package, the laminated film comprising an inner layer, an adhesive layer, and a functional layer, the inner layer and the functional layer being bonded together by the adhesive layer, the inner layer containing polyethylene, the functional layer containing either or both of polyamide and ethylene-vinyl alcohol copolymer, the adhesive layer containing an adhesive resin, and the adhesive resin having a Vicat softening temperature of 90°C or higher. [2] The laminated film according to [1], wherein the adhesive resin has a melt flow rate of 3 g / 10 min or less. [3] The density of the adhesive resin is 0.91 g / cm 3 The laminate film according to [1] or [2] above. [4] The laminate film according to any one of [1] to [3], wherein the adhesive resin is an acid-modified polyethylene.

[0008] [5] The laminate film according to any one of [1] to [4], wherein the inner layer has a thickness of 10 to 100 μm. [6] The laminate film according to any one of [1] to [5], wherein the polyethylene contained in the inner layer has a Vicat softening temperature of 90° C. or higher.

[0009] [7] The laminate film described in any one of [1] to [6], further comprising an outer layer provided on the side of the functional layer opposite the adhesive layer, the outer layer comprising one or more types selected from the group consisting of polyethylene, polypropylene and polyamide. [8] The laminate film described in [7], further comprising an intermediate layer disposed between the outer layer and the functional layer, the intermediate layer containing polyethylene. [9] The laminated film described in [8], wherein the polyethylene has a Vicat softening temperature of 90°C or higher.

[10] The laminated film described in [8] or [9], wherein the polyethylene is biomass-derived polyethylene.

[11] The laminate film described in any one of [7] to

[10] , wherein the outer layer contains the polyethylene having a Vicat softening temperature of 90° C. or higher.

[0010]

[12] A packaging material formed using the laminate film according to any one of [1] to

[11] .

[13] The packaging body described in

[12] , wherein the packaging body has a lid material and a base material, the packaging body is formed by sealing the lid material and the base material, and the base material is formed using the laminate film. Effect of the Invention

[0011] According to the present invention, there is provided a laminated film formed by stacking a plurality of resin layers, which is capable of suppressing breakage of the package when the package is produced by packaging a food product containing a liquid using the laminated film and heat-treating the package with hot water. [Brief description of the drawings]

[0012] [Figure 1] FIG. 1 is a cross-sectional view illustrating an example of a laminated film according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a cross-sectional view illustrating a schematic view of another example of a laminate film according to one embodiment of the present invention. [Diagram 3] FIG. 2 is a cross-sectional view illustrating a schematic view of still another example of a laminate film according to one embodiment of the present invention. [Figure 4] FIG. 2 is a cross-sectional view illustrating a schematic view of still another example of a laminate film according to one embodiment of the present invention. [Diagram 5] FIG. 1 is a cross-sectional view showing a schematic example of a packaging body according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] <<Laminated film>> One embodiment of the present invention relates to a laminated film for producing a package in which a food containing a liquid is packaged, and for heat-treating the package, the laminated film comprising an inner layer, an adhesive layer, and a functional layer, the inner layer and the functional layer being bonded together by the adhesive layer, the inner layer comprising polyethylene, the functional layer comprising either or both of polyamide and ethylene-vinyl alcohol copolymer, the adhesive layer comprising an adhesive resin, and the adhesive resin having a Vicat softening temperature of 90°C or higher.

[0014] In the laminated film of the present embodiment, the inner layer functions, for example, as a sealant layer. The functional layer imparts some function to the laminate film, such as a function to protect the laminate film itself or a suitable oxygen barrier property. The adhesive layer bonds the inner layer and the functional layer.

[0015] The laminated film of the present embodiment is suitable for packaging food containing liquids. When the package obtained by packaging such food is heat-treated (boiled) with hot water, the package can be prevented from breaking. This is because the adhesive layer constituting the laminated film contains an adhesive resin with a Vicat softening temperature of 90° C. or higher.

[0016] When packaging foods containing liquids in a resin film, for example, a lid material made of a resin film and a base material which is a molded body of the resin film are used, the food is placed in a recess in the base material, the area near the periphery other than the recess of the base material is overlapped with an area near the periphery of the lid material, and these overlapping areas are heat-sealed in a reduced pressure environment to form a reduced pressure storage area, and the food is then stored in this storage area to produce a package.

[0017] However, when food containing liquid is packaged using this method, the liquid may become trapped in the seal between the lid and base material, causing the seal strength to be insufficient due to the trapped liquid, which may damage the seal and cause the package to break at an unintended time.

[0018] In order to prevent such a problem, the conditions for heat sealing the lid material and the base material may be adjusted. More specifically, it has been found that the inclusion of liquid at the seal portion is likely to occur when the sealing surface of the lid material and the sealing surface of the base material are both highly flat. Therefore, when heat sealing the lid material and the base material, the sealing pressure is increased from the lid material side to the base material side more than usual, so that the shape of the heat sealed portion is made to protrude from the lid material side to the base material side. It has been found that this can prevent the inclusion of liquid at the seal portion.

[0019] However, when a conventional laminated film having a structure in which an inner layer, an adhesive layer, and an intermediate layer are laminated in this order is used as the base material (resin film), a part of the package obtained by heat sealing as described above may break when it is heat-treated at a temperature higher than normal. Such breakage does not occur under conditions in which the heating temperature is controlled, such as heat sterilization, but occurs exceptionally when the heating temperature rises excessively. For example, when a general consumer heats a package before eating, if the heating temperature rises excessively, the package is likely to break. In particular, when a package is heat-treated by boiling water in a closed space such as a pot filled with boiling water and covered with a lid, the temperature in the space is likely to rise excessively, and the pressure in the storage section of the package is also likely to rise excessively, making the package even more likely to break. It is presumed that the pressure in the storage section of the package is likely to rise because the solvent component of the liquid material is likely to evaporate.

[0020] As a result of analyzing the phenomenon that the package breaks due to such excessive heat treatment, it was found that in the heat-sealed area having a protruding shape as described above, the thickness of the layer derived from the base material, particularly the adhesive layer, is excessively thin, and the interlayer adhesion strength is reduced in this area. It was also found that when the package is heat-treated at an excessively high temperature, the inner layer is damaged in the heat-sealed area having a protruding shape, and peeling occurs between the adhesive layer and the intermediate layer in this damaged area, resulting in the package breaking. That is, it was found that by heat-sealing the base material having a structure in which the inner layer, adhesive layer, and intermediate layer are laminated in this order and the lid material as described above, and making the shape of the heat-sealed area protruding, the inclusion of liquid is suppressed in the seal part between the lid material and the base material, but the interlayer adhesion strength is reduced due to the excessive thinness of the adhesive layer, and when the package is heat-treated at an excessively high temperature, the package is broken.

[0021] In contrast, the laminated film of this embodiment is molded to produce a base material, and the use of this base material can suppress the above-mentioned package from breaking. This is because the adhesive resin contained in the adhesive layer has a high Vicat softening temperature of 90°C or higher. It is presumed that the Vicat softening temperature of the adhesive resin is 90°C or higher, so that even if a package is manufactured by forming a protruding heat-sealed portion as described above and the package is heat-treated at an excessively high temperature, such as by heating the package with hot water, an increase in the fluidity of the adhesive layer is suppressed, and as a result, a decrease in the interlayer adhesion strength between the adhesive layer and the layer adjacent thereto is suppressed.

[0022] Up to this point, we have used the example of heat sealing a lid material and a base material, but the above-mentioned problems can also arise when heat sealing laminated films that are not molded bodies together. In that case too, the problems can be solved by using the laminated film of this embodiment.

[0023] The present invention will be described in detail below with reference to the drawings. Note that the drawings used in the following description may show essential parts in an enlarged scale for the sake of convenience in order to make the features of the present invention easier to understand, and the dimensional ratios of each component may not necessarily be the same as in reality.

[0024] FIG. 1 is a cross-sectional view that illustrates an example of the laminated film of the present embodiment. The laminated film 1 shown here comprises an inner layer 11, an adhesive layer 13, and a functional layer 12, and is configured such that the inner layer 11 and the functional layer 12 are bonded together by the adhesive layer 13. The laminated film 1 further includes an outer layer 14 provided on a surface 12a of the functional layer 12 opposite to the adhesive layer 13 side. The laminated film 1 further includes an intermediate layer 15 provided between the outer layer 14 and the functional layer 12 . The laminate film 1 further comprises an outer adhesive layer 16 provided between the intermediate layer 15 and the functional layer 12 . That is, the laminated film 1 is constructed by laminating an inner layer 11, an adhesive layer 13, a functional layer 12, an outer adhesive layer 16, an intermediate layer 15 and an outer layer 14 in this order in the thickness direction.

[0025] The inner layer 11 comprises polyethylene. The functional layer 12 contains either or both of a polyamide and an ethylene-vinyl alcohol copolymer. The adhesive layer 13 contains an adhesive resin, and the adhesive resin has a Vicat softening temperature of 90° C. or higher.

[0026] The inner layer 11 is one of the outermost layers of the laminated film 1 . One surface 11b of the inner layer 11 (the surface opposite to the functional layer 12 side, sometimes referred to as the "second surface" in this specification) is an exposed surface (one of the outermost surfaces). For example, when the inner layer 11 is a sealant layer, the second surface 11b of the inner layer 11 is a sealing surface with another resin film or a molded product thereof. As described later, in a package formed by sealing the inner layer 11 with another resin film or a molded product thereof, the non-sealed area of ​​the second surface 11b of the inner layer 11 forms a storage section in the package.

[0027] The outer layer 14 is the other outermost layer of the laminated film 1 and enhances protection of the other components of the laminated film 1. One side 14a of the outer layer 14 (the side opposite the inner layer 11; sometimes referred to as the "first side" in this specification) is the exposed side (the other outermost surface), and even in the packaging body configured as described above, the first side 14a of the outer layer 14 is the exposed side (the other outermost surface).

[0028] When intermediate layer 15 is provided adjacent to outer layer 14 (in contact with outer layer 14) on the inner layer 11 side as shown here, it is preferable that intermediate layer 15 is a layer having a function that outer layer 14 does not have, and further, intermediate layer 15 may or may not have a function similar to that of outer layer 14. For example, a preferred intermediate layer 15 includes a layer that includes a biomass-derived resin and also functions as an outer layer.

[0029] In the laminated film of the present embodiment, by using a resin derived from biomass, it is possible to reduce the amount of petroleum resources used and to reduce the amount of carbon dioxide emitted during the production and disposal of the laminated film. In other words, such a laminated film has a remarkable effect in terms of reducing the environmental load.

[0030] The outer adhesive layer 16 is disposed on the laminate film 1 on the side opposite to the inner layer 11 side of the functional layer 12 (i.e., on the outside closer to the outer layer 14 than the adhesive layer 13) and bonds the two layers adjacent to it (the outer adhesive layer 16) in the same manner as the adhesive layer 13. That is, the functional layer 12 and the intermediate layer 15 are bonded by the outer adhesive layer 16.

[0031] In this specification, unless otherwise specified, the term "adhesive layer" simply means a layer that bonds an inner layer and a functional layer, and does not mean an outer adhesive layer.

[0032] FIG. 2 is a cross-sectional view that illustrates a schematic view of another example of the laminated film of the present embodiment. In FIG. 2 and subsequent figures, the same components as those shown in the figures already described are given the same reference numerals as in the figures already described, and detailed description thereof will be omitted.

[0033] The laminated film 2 shown here is the same as the laminated film 1 shown in FIG. 1, except that it further comprises an intermediate layer between the inner layer 11 and the adhesive layer 13 in direct contact therewith. In this way, when the laminated film of the present embodiment includes an intermediate layer on the outer layer side of the functional layer and also includes an intermediate layer on the inner layer side of the functional layer, in this specification, the intermediate layer on the inner layer side of the functional layer may be referred to as the "first intermediate layer," and the intermediate layer on the outer layer side of the functional layer may be referred to as the "second intermediate layer." The laminated film 2 shown in Figure 2 includes a second intermediate layer 152 on the outer layer 14 side of the functional layer 12, and a first intermediate layer 151 on the inner layer 11 side of the functional layer 12. That is, the laminated film 2 is constructed by laminating an inner layer 11, a first intermediate layer 151, an adhesive layer 13, a functional layer 12, an outer adhesive layer 16, a second intermediate layer 152 and an outer layer 14 in this order in the thickness direction.

[0034] The second intermediate layer 152 in the laminate film 2 is the same as the intermediate layer 15 in the laminate film 1 .

[0035] When the first intermediate layer 151 in the laminate film 2 is disposed adjacent to the inner layer 11 (in contact with the inner layer 11) on the outer layer 14 side as shown here, it is preferable that it is a layer having a function that the inner layer 11 does not have, and further, it may or may not have a function similar to that of the inner layer 11. For example, a preferred first intermediate layer 151 is a layer that contains a resin derived from biomass and also functions as an inner layer.

[0036] FIG. 3 is a cross-sectional view that illustrates a schematic view of still another example of the laminated film of the present embodiment. The laminate film 3 shown here is the same as the laminate film 2 shown in FIG. In the laminated film 3 , the outer adhesive layer 16 bonds the two layers adjacent thereto (the outer adhesive layer 16 ), and the functional layer 12 and the outer layer 14 are bonded by the outer adhesive layer 16 . That is, the laminated film 3 is constructed by laminating an inner layer 11, an intermediate layer 15, an adhesive layer 13, a functional layer 12, an outer adhesive layer 16 and an outer layer 14 in this order in the thickness direction.

[0037] FIG. 4 is a cross-sectional view that illustrates a schematic view of still another example of the laminated film of the present embodiment. The laminate film 4 shown here is the same as the laminate film 1 shown in FIG. In the laminated film 4 , the outer adhesive layer 16 bonds the two layers adjacent thereto (the outer adhesive layer 16 ), and the functional layer 12 and the outer layer 14 are bonded by the outer adhesive layer 16 . That is, the laminated film 4 is constructed by laminating an inner layer 11, an adhesive layer 13, a functional layer 12, an outer adhesive layer 16 and an outer layer 14 in this order in the thickness direction.

[0038] The laminate film of this embodiment is not limited to laminate film 1, laminate film 2, laminate film 3 or laminate film 4, and some of the configurations of these laminate films 1 to 3 may be changed, deleted or added within the scope of the present invention.

[0039] For example, the laminate film 2 includes the inner layer 11, the first intermediate layer 151, the adhesive layer 13, the functional layer 12, the outer adhesive layer 16, the second intermediate layer 152, and the outer layer 14, but the laminate film of this embodiment may include layers other than these. However, it is preferable that the laminate film of this embodiment does not include the other layers. For example, it is preferable that the laminated film 1 shown in Figure 1 does not have the other layers, and that the inner layer 11, adhesive layer 13, functional layer 12, outer adhesive layer 16, intermediate layer 15 and outer layer 14 are laminated in this order in direct contact with each other in the thickness direction. It is preferable that the laminated film 2 shown in Figure 2 does not have the other layers, and that the inner layer 11, first intermediate layer 151, adhesive layer 13, functional layer 12, outer adhesive layer 16, second intermediate layer 152 and outer layer 14 are laminated in this order and in direct contact with each other in the thickness direction. It is preferable that the laminated film 3 shown in Figure 3 does not include the other layers, and that the inner layer 11, intermediate layer 15, adhesive layer 13, functional layer 12, outer adhesive layer 16 and outer layer 14 are laminated in this order in direct contact with each other in the thickness direction. It is preferable that the laminated film 4 shown in Figure 4 does not include the other layers, and that the inner layer 11, adhesive layer 13, functional layer 12, outer adhesive layer 16 and outer layer 14 are laminated in this order in direct contact with each other in the thickness direction.

[0040] The laminated film of the present embodiment may include at least an inner layer, an adhesive layer, and a functional layer, and the other layers are optional. However, in terms of enhancing the protective function of the laminated film, it is preferable that the laminated film of the present embodiment further includes an outer layer and an outer adhesive layer. Next, each layer constituting the laminated film of the present embodiment will be described in more detail.

[0041] <Inner layer> The inner layer contains polyethylene (PE) and has good heat sealability with other resin films or molded articles thereof.

[0042] In the inner layer, the ratio of the total content of one or more components contained in the inner layer, which will be described later, to the total mass of the inner layer does not exceed 100 mass %. Similarly, in the composition for forming an inner layer described later, the ratio of the total content of one or more components contained in the composition for forming an inner layer described later to the total mass of the composition for forming an inner layer does not exceed 100 mass%.

[0043] Examples of the polyethylene contained in the inner layer include low density polyethylene (LDPE), linear low density polyethylene (LLDPE), metallocene-catalyzed linear low density polyethylene (mLLDPE), medium density polyethylene (MDPE), and high density polyethylene (HDPE).

[0044] In this specification, the density of low density polyethylene (LDPE), linear low density polyethylene (LLDPE) and metallocene-catalyzed linear low density polyethylene (mLLDPE) is 0.910 g / cm 3 More than 0.945g / cm 3 is less than. The density of medium density polyethylene (MDPE) is 0.945 g / cm 3 More than 0.955g / cm 3 is less than. The density of high density polyethylene (HDPE) is 0.955 g / cm 3 That's all.

[0045] The Vicat softening temperature of the polyethylene contained in the inner layer is preferably 90° C. or higher, more preferably 100° C. or higher, and even more preferably 110° C. or higher. When the Vicat softening temperature is equal to or higher than the lower limit, damage to the inner layer is more highly suppressed not only in the protruding portions described above but also in the heat-sealed portions when a package, which will be described later, obtained by heat-sealing the laminated film to an object is subjected to a heat treatment. On the other hand, the upper limit of the Vicat softening temperature is not particularly limited. For example, polyethylene having a Vicat softening temperature of 130° C. or lower is more easily available or produced. In one embodiment, the Vicat softening temperature of the polyethylene contained in the inner layer may be, for example, any one of 90 to 130° C., 100 to 130° C., and 110 to 130° C. However, these are only examples of the Vicat softening temperature.

[0046] The melting point of the polyethylene contained in the inner layer is preferably 110 to 130° C., more preferably 120 to 130° C., and even more preferably 125 to 130° C. When the melting point of the polyethylene is equal to or higher than the lower limit, the seal strength between the laminated film and the object of heat sealing is higher. When the melting point of the polyethylene is equal to or lower than the upper limit, the heat sealing time of the laminated film can be shortened, and the productivity of the package described below can be improved.

[0047] In this specification, the term "melting point" refers to a value measured in accordance with JIS K 7121, not limited to the case of polyethylene, unless otherwise specified.

[0048] The melt flow rate (also referred to as "melt mass flow rate"; in this specification, sometimes referred to as "MFR") of the polyethylene contained in the inner layer is preferably 6 g / 10 min or less, more preferably 5 g / 10 min or less, and even more preferably 4 g / 10 min or less. When the MFR of the polyethylene is equal to or less than the upper limit, damage to the inner layer is more highly suppressed not only in the protruding portions but also in the heat-sealed portions when the above-mentioned package is heat-treated. On the other hand, the lower limit of the MFR of the polyethylene is not particularly limited. For example, polyethylene with an MFR of 2 g / 10 min or more is more easily available or produced. In one embodiment, the MFR of the polyethylene contained in the inner layer may be any one of 2 to 6 g / 10 min, 2 to 5 g / 10 min, and 2 to 4 g / 10 min, although these are only examples of the MFR.

[0049] In this specification, not limited to the case of polyethylene, "MFR" means a value measured in accordance with ASTM D1238, unless otherwise specified.

[0050] Not only in the case of polyethylene, but also in any case, physical properties such as the Vicat softening temperature, melting point, and melt flow rate of a resin can be adjusted by adjusting the type of monomer, the molecular weight of the resin, the degree of molecular branching, and the like.

[0051] The inner layer may contain only one type of polyethylene, or two or more types. When two or more types are contained, the combination and ratio thereof can be arbitrarily selected depending on the purpose.

[0052] From the viewpoints of improving the sealing characteristics when the laminated film is heat-sealed to an object, of more effectively suppressing damage to the inner layer not only at the protruding portions but also at the heat-sealed portions when the package obtained by heat sealing is heat-treated, of increasing the transparency of the inner layer, and of high impact resistance under freezing conditions, it is preferable that the polyethylene contained in the inner layer is one or more types selected from the group consisting of low-density polyethylene, linear low-density polyethylene, and metallocene-catalyzed linear low-density polyethylene, and more preferably either one or both of linear low-density polyethylene and metallocene-catalyzed linear low-density polyethylene.

[0053] The inner layer may or may not contain other components that do not fall under the category of polyethylene, as long as the effects of the present invention are not impaired. The other components contained in the inner layer may be either resin components (sometimes referred to as "other resin components" in this specification) or non-resin components (sometimes referred to as "other non-resin components" in this specification).

[0054] The other resin component contained in the inner layer is not particularly limited as long as it is a resin other than polyethylene. Examples of the other resin components contained in the inner layer include polyolefins other than polyethylene. Examples of the polyolefin other than polyethylene contained in the inner layer include ethylene-based copolymers, homopolypropylene (hPP), and propylene-based copolymers.

[0055] In this specification, the term "ethylene-based copolymer", including but not limited to that contained in the inner layer, means a copolymer having a structural unit derived from ethylene and a structural unit derived from a monomer other than ethylene.

[0056] Examples of the ethylene-based copolymer contained in the inner layer include ethylene-vinyl acetate copolymer (EVA), ethylene-vinyl alcohol-vinyl acetate copolymer (also known as partially saponified ethylene-vinyl acetate copolymer), ethylene-vinyl alcohol copolymer (EVOH, also known as saponified ethylene-vinyl acetate copolymer), ethylene-methyl acrylate copolymer (EMA), ethylene-methyl methacrylate copolymer (EMMA), ethylene-ethyl acrylate copolymer (EEA), ethylene-acrylic acid copolymer (EAA), ethylene-methacrylic acid copolymer (EMAA), ethylene-ethyl acrylate-maleic anhydride copolymer (E-EA-MAH), and ionomer (ION). The ionomer may be, for example, a resin in which a copolymer of ethylene and a small amount of acrylic acid or methacrylic acid has an ionic crosslinking structure due to salt formation between the acid portion in the copolymer and a metal ion.

[0057] In this specification, the term "propylene-based copolymer", including but not limited to that contained in the inner layer, means a copolymer having a structural unit derived from propylene and a structural unit derived from a monomer other than propylene.

[0058] Examples of the propylene-based copolymer contained in the inner layer include propylene-ethylene random copolymer (also known as polypropylene random copolymer (rPP)) and propylene-ethylene block copolymer (also known as polypropylene block copolymer (bPP)).

[0059] In this specification, not only in the case of the inner layer, but among polyolefins (olefin-based copolymers) having structural units derived from ethylene and structural units derived from propylene, copolymers in which the number of structural units derived from propylene is greater than the number of structural units derived from ethylene are classified as propylene-based copolymers.

[0060] Examples of the other non-resin components contained in the inner layer include additives known in the art. Examples of the additives include antifogging agents, antiblocking agents, antioxidants, antistatic agents, crystal nucleating agents, inorganic particles, viscosity reducers, thickeners, heat stabilizers, lubricants, infrared absorbers, and ultraviolet absorbers.

[0061] The other components contained in the inner layer may be one type only, or two or more types. When there are two or more types, the combination and ratio thereof can be arbitrarily selected depending on the purpose.

[0062] In the inner layer, the ratio of the polyethylene content to the total mass of the inner layer ([polyethylene content of the inner layer (parts by mass)] / [total mass of the inner layer (parts by mass)]×100) is preferably 90 to 100% by mass, more preferably 95 to 100% by mass, and may be, for example, any one of 97 to 100% by mass and 99 to 100% by mass. When the ratio is equal to or greater than the lower limit, the effect obtained by the inner layer containing polyethylene is enhanced. The above ratio is usually the same as the ratio of the polyethylene content to the total content (parts by mass) of components that do not vaporize at room temperature in the composition for forming the inner layer described below ([polyethylene content (parts by mass) in the composition for forming the inner layer)] / [total content (parts by mass) of components that do not vaporize at room temperature in the composition for forming the inner layer)]×100).

[0063] In this specification, "room temperature" means a temperature that is neither particularly cooled nor heated, that is, an ordinary temperature, and examples thereof include temperatures of 15 to 25°C.

[0064] In terms of improving the properties as an inner layer, the polyethylene contained in the inner layer is preferably one or more types selected from the group consisting of low-density polyethylene, linear low-density polyethylene, and metallocene-catalyzed linear low-density polyethylene, and more preferably one or both of linear low-density polyethylene and metallocene-catalyzed linear low-density polyethylene.

[0065] In the inner layer, the ratio of the total content of the linear low density polyethylene and the metallocene-catalyzed linear low density polyethylene to the polyethylene content (([linear low density polyethylene content of the inner layer (parts by mass)] + [metallocene-catalyzed linear low density polyethylene content of the inner layer (parts by mass)]) / [polyethylene content of the inner layer (parts by mass)] × 100) is preferably 80 mass% or more, more preferably 90 mass% or more, and may be, for example, any one of 95 mass% or more, 97 mass% or more, and 99 mass% or more. When the ratio is equal to or more than the lower limit, the effect obtained by the inner layer containing the linear low density polyethylene or the metallocene-catalyzed linear low density polyethylene is further enhanced. On the other hand, the proportion is 100% by mass or less. The above ratio is usually the same as the ratio of the total content (parts by mass) of the linear low-density polyethylene and the metallocene-catalyzed linear low-density polyethylene to the polyethylene content (parts by mass) in the composition for forming an inner layer described below (([content (parts by mass) of linear low-density polyethylene in the composition for forming an inner layer)] + [content (parts by mass) of metallocene-catalyzed linear low-density polyethylene in the composition for forming an inner layer)]) / [content (parts by mass) of polyethylene in the composition for forming an inner layer)] × 100). Here, when the inner layer or the composition for forming an inner layer does not contain a linear low density polyethylene, the content of the linear low density polyethylene in the inner layer or the composition for forming an inner layer is 0 part by mass. When the inner layer or the composition for forming an inner layer does not contain a metallocene-catalyzed linear low density polyethylene, the content of the metallocene-catalyzed linear low density polyethylene in the inner layer or the composition for forming an inner layer is 0 part by mass.

[0066] The inner layer may be one layer (single layer) or two or more layers. When the inner layer is made up of multiple layers, these multiple layers may be the same or different from each other, and the combination of these multiple layers is not particularly limited as long as it does not impair the effects of the present invention. The inner layer preferably consists of one layer (single layer).

[0067] In this specification, not only in the case of inner layers, but also in the case where, for example, two layers of the same type consisting of a single layer are arranged apart from each other without being directly laminated in a laminate film, these layers are not regarded as consisting of two layers (multiple layers), but are regarded as layers consisting of a single layer arranged in different positions in the laminate film. Similarly, if a layer consisting of two layers and a layer consisting of one layer are both the same type of layer and are positioned apart from each other without being directly laminated in the laminate film, these layers are not considered to be composed of three layers, but the layer consisting of two layers and the layer consisting of one layer are considered to be positioned in different positions in the laminate film. The same applies to other combinations of the number of layers.

[0068] The ratio of the thickness of the inner layer to the thickness of the laminated film ([thickness of the inner layer] / [thickness of the laminated film]×100) is preferably 20 to 92%, more preferably 20 to 60%, and may be, for example, any of 20 to 32%, 28 to 42%, and 38 to 50%. When the ratio is equal to or more than the lower limit, the effect obtained by the laminated film having the inner layer is enhanced. When the ratio is equal to or less than the upper limit, the thickness of the inner layer is prevented from becoming excessive. For example, the effect obtained by the laminated film having a layer other than the inner layer (for example, a functional layer, an adhesive layer) is enhanced.

[0069] The thickness of the inner layer is preferably 10 to 184 μm, more preferably 10 to 120 μm, and may be, for example, any of 10 to 35 μm, 25 to 85 μm, and 75 to 120 μm. When the thickness of the inner layer is equal to or greater than the lower limit, the effect obtained by providing the inner layer in the laminated film is enhanced. When the thickness of the inner layer is equal to or less than the upper limit, the inner layer is prevented from becoming excessively thick. When the inner layer is made up of a plurality of layers, the total thickness of these layers is preferably within the above-mentioned numerical range.

[0070] <Adhesive layer> The adhesive layer contains an adhesive resin and bonds the inner layer and the functional layer in the laminated film.

[0071] In the adhesive layer, the ratio of the total content of one or more components contained in the adhesive layer, which will be described later, to the total mass of the adhesive layer does not exceed 100 mass %. Similarly, in the adhesive layer-forming composition described below, the ratio of the total content of one or more of the components contained in the adhesive layer-forming composition described below to the total mass of the adhesive layer-forming composition does not exceed 100 mass%.

[0072] The adhesive resin contained in the adhesive layer has a Vicat softening temperature of 90° C. or higher. When the Vicat softening temperature is 90° C. or higher, when a package obtained by heat-sealing the laminated film to an object is heat-treated, breakage of the package is suppressed at heat-sealed portions, particularly at the above-mentioned protruding heat-sealed portions.

[0073] In this specification, the mere term "adhesive resin" means an adhesive resin having a Vicat softening temperature of 90° C. or higher, unless otherwise specified.

[0074] In this way, in order to achieve a greater effect in preventing the packaging from breaking, the Vicat softening temperature of the adhesive resin contained in the adhesive layer is preferably 95°C or higher, more preferably 100°C or higher, and even more preferably 105°C or higher. On the other hand, the upper limit of the Vicat softening temperature is not particularly limited. For example, polyethylene having a Vicat softening temperature of 115° C. or lower is more easily available or produced. In one embodiment, the Vicat softening temperature of the adhesive resin contained in the adhesive layer may be, for example, any one of 90 to 115° C., 95 to 115° C., 100 to 115° C., and 105 to 115° C. However, these are only examples of the Vicat softening temperature.

[0075] The adhesive resin contained in the adhesive layer preferably has a melt flow rate (MFR) of 3 g / 10 min or less, more preferably 2.5 g / 10 min or less, and even more preferably 2 g / 10 min or less. When the MFR of the adhesive resin is equal to or less than the upper limit, the effect of suppressing the breakage of the package at the heat-sealed portion, particularly the protruding heat-sealed portion, when the package is heat-treated is enhanced. On the other hand, the lower limit of the MFR of the adhesive resin is not particularly limited. For example, an adhesive resin having an MFR of 1 g / 10 min or more can be more easily obtained or produced. In one embodiment, the MFR of the adhesive resin contained in the adhesive layer may be, for example, any one of 1 to 3 g / 10 min, 1 to 2.5 g / 10 min, and 1 to 2 g / 10 min, although these are only examples of the MFR.

[0076] The density of the adhesive resin contained in the adhesive layer is 0.91 g / cm 3 It is preferable that the content is 0.92 g / cm or more. 3 More preferably, it is 0.93 g / cm or more. 3 When the density of the adhesive resin is equal to or greater than the lower limit, the effect of suppressing tearing of the package at the heat-sealed portion, particularly the protruding heat-sealed portion, when the package is heat-treated is increased. On the other hand, the upper limit of the density of the adhesive resin is not particularly limited. For example, when the density of the adhesive resin is 0.94 g / cm 3 The adhesive resins that are less readily available or manufactured. In one embodiment, the density of the adhesive resin contained in the adhesive layer is, for example, 0.91 to 0.94 g / cm 3 , 0.92~0.94g / cm 3 , and 0.93 to 0.94 g / cm 3 However, these are just examples of the density.

[0077] The adhesive resin contained in the adhesive layer has a melting point of preferably 110° C. or higher, more preferably 115° C. or higher, and even more preferably 120° C. or higher. When the adhesive resin has a melting point equal to or higher than the lower limit, the effect of suppressing breakage of the package at the heat-sealed portion, particularly the protruding heat-sealed portion, when the package is heat-treated is enhanced. On the other hand, the upper limit of the melting point of the adhesive resin is not particularly limited. For example, an adhesive resin having a melting point of 125° C. or less can be more easily obtained or produced. In one embodiment, the melting point of the adhesive resin contained in the adhesive layer may be any one of 110 to 125° C., 115 to 125° C., and 120 to 125° C. However, these are only examples of the melting point.

[0078] The physical properties of the adhesive resin, such as its Vicat softening temperature, melting point, and melt flow rate, can be adjusted by adjusting the type of monomer, the molecular weight of the resin, the degree of molecular branching, etc. In particular, in the case of a modified copolymer described below, the physical properties can be easily adjusted by adjusting the degree of modification.

[0079] The adhesive resin contained in the adhesive layer may be, for example, a polyolefin resin. The polyolefin resin is a resin having structural units derived from an olefin, and may be a homopolymer of one type of olefin or a copolymer of two or more types of olefins.

[0080] Examples of the polyolefin resin that is an adhesive resin include ethylene-based copolymers, propylene-based copolymers, butene-based copolymers, modified products of these copolymers (in other words, modified copolymers), acid-modified polyethylene, and acid-modified polypropylene. The polyolefin resin may be a random copolymer, a graft copolymer or a block copolymer, from the viewpoint of further improving adhesiveness.

[0081] In this specification, the term "butene-based copolymer" refers to a copolymer having a structural unit derived from butene and a structural unit derived from a monomer other than butene, including but not limited to those contained in the adhesive layer.

[0082] Examples of the ethylene copolymer that is the adhesive resin include the ethylene copolymers described above as being contained in the inner layer, and modified products thereof (modified copolymers). Examples of the propylene-based copolymer that is the adhesive resin include copolymers of propylene and vinyl group-containing monomers, modified products thereof (modified copolymers), etc., including the propylene-based copolymers described above as those contained in the inner layer. More specifically, examples of such propylene-based copolymers include linear low-density polypropylene grafted with maleic anhydride, propylene-based thermoplastic elastomers, etc. Examples of the butene copolymer that is an adhesive resin include a copolymer of 1-butene and a vinyl group-containing monomer, a copolymer of 2-butene and a vinyl group-containing monomer, and modified products of these copolymers (modified copolymers).

[0083] The adhesive resin contained in the adhesive layer is preferably a modified polyolefin such as an acid-modified polyolefin having an acidic group, more preferably a modified polyethylene such as an acid-modified polyethylene having an acidic group, and even more preferably an acid-modified polyethylene.

[0084] The adhesive layer may contain only one type of adhesive resin, or two or more types. When two or more types are contained, the combination and ratio thereof can be arbitrarily selected depending on the purpose.

[0085] The adhesive layer may or may not contain other components that do not fall under the category of the adhesive resin, as long as the effects of the present invention are not impaired. The other components contained in the adhesive layer may be either resin components (sometimes referred to in this specification as "other resin components") or non-resin components (sometimes referred to in this specification as "other non-resin components").

[0086] The other resin components contained in the adhesive layer are not particularly limited as long as they are resins that do not fall under the category of adhesive resins having a Vicat softening temperature of 90° C. or higher. Examples of the other resin components include adhesive resins having a Vicat softening temperature of less than 90° C., non-adhesive resins (resins that do not have adhesive properties), and the like.

[0087] Examples of the other non-resin components contained in the adhesive layer include the same non-resin components as those contained in the inner layer.

[0088] The adhesive layer may contain only one type of other component, or two or more types. When there are two or more types, the combination and ratio thereof can be arbitrarily selected depending on the purpose.

[0089] In the adhesive layer, the ratio of the content of adhesive resin having a Vicat softening temperature of 90°C or higher to the total mass of the adhesive layer ([content of adhesive resin having a Vicat softening temperature of 90°C or higher (parts by mass)] / [total mass of adhesive layer (parts by mass)]×100) is preferably 90 to 100% by mass, more preferably 95 to 100% by mass, and may be, for example, any of 97 to 100% by mass and 99 to 100% by mass. When the ratio is equal to or higher than the lower limit, the effect of suppressing tearing of the package at the heat-sealed portions, particularly the protruding heat-sealed portions, when the package is heat-treated is enhanced. The above ratio is usually the same as the ratio of the content of adhesive resin having a Vicat softening temperature of 90°C or higher to the total content (parts by mass) of components that do not vaporize at room temperature in the composition for forming an adhesive layer described below ([content (parts by mass) of adhesive resin having a Vicat softening temperature of 90°C or higher in the composition for forming an adhesive layer] / [total content (parts by mass) of components that do not vaporize at room temperature in the composition for forming an adhesive layer] × 100).

[0090] In the adhesive layer, the ratio of the modified polyolefin content to the adhesive resin content having a Vicat softening temperature of 90°C or higher ([modified polyolefin content in adhesive layer (parts by mass)] / [adhesive resin content in adhesive layer having a Vicat softening temperature of 90°C or higher (parts by mass)] x 100) is preferably 80% by mass or higher, more preferably 90% by mass or higher, and may be, for example, any of 95% by mass or higher, 97% by mass or higher, and 99% by mass or higher. When the ratio is equal to or higher than the lower limit, the effect of suppressing tearing of the package at the heat-sealed portions, particularly the protruding heat-sealed portions, when the package is heat-treated is further enhanced. On the other hand, the proportion is 100% by mass or less. The above ratio is usually the same as the ratio of the modified polyolefin content (parts by mass) to the adhesive resin content (parts by mass) having a Vicat softening temperature of 90°C or higher in the adhesive layer-forming composition described below ([modified polyolefin content (parts by mass) in the adhesive layer-forming composition)] / [adhesive resin content (parts by mass) having a Vicat softening temperature of 90°C or higher in the adhesive layer-forming composition] x 100).

[0091] The adhesive layer may be one layer (single layer) or two or more layers. When the adhesive layer is made of multiple layers, these layers may be the same or different from each other, and the combination of these layers is not particularly limited as long as it does not impair the effects of the present invention. The adhesive layer preferably consists of one layer (single layer).

[0092] The ratio of the thickness of the adhesive layer to the thickness of the laminated film ([thickness of adhesive layer] / [thickness of laminated film]×100) is preferably 3 to 20%, more preferably 5 to 10%, and may be, for example, any of 5 to 8% and 7 to 10%. When the ratio is equal to or more than the lower limit, the effect obtained by the laminated film having an adhesive layer is enhanced. When the ratio is equal to or less than the upper limit, the adhesive layer is prevented from becoming excessively thick. For example, the effect obtained by the laminated film having a layer other than the adhesive layer (for example, an inner layer, a functional layer) is enhanced.

[0093] The thickness of the adhesive layer is preferably from 1.5 to 40 μm, more preferably from 2.5 to 20 μm, and may be, for example, any one of 2.5 to 9 μm, 6 to 15 μm, and 12 to 20 μm. When the adhesive layer is made up of multiple layers, the total thickness of these multiple layers is preferably within the above numerical range.

[0094] <Example of the relationship between the thickness of the inner layer and the Vicat softening temperature of the adhesive resin> The Vicat softening temperature of the adhesive resin contained in the adhesive layer may be adjusted according to the thickness of the inner layer. The reason is that the functional layer has a higher effect of suppressing heat transfer than the inner layer, and therefore, when the laminated film or its molded body is heat-sealed, the temperature of the adhesive layer is more affected by heating from the inner layer side than by heating from the functional layer side. That is, usually, the thicker the inner layer is, the more difficult it is for the temperature of the adhesive layer to rise during heat-sealing.

[0095] For example, when the thickness of the inner layer is 45 μm or less (for example, 10 to 45 μm), the Vicat softening temperature of the adhesive resin contained in the adhesive layer may be 105 to 115°C. For example, when the thickness of the inner layer is 40 to 75 μm, the Vicat softening temperature of the adhesive resin contained in the adhesive layer may be any one of 95 to 115°C and 100 to 115°C. For example, when the thickness of the inner layer is 70 μm or more (eg, 70 to 100 μm), the Vicat softening temperature of the adhesive resin contained in the adhesive layer may be any one of 90 to 115°C, 95 to 115°C, and 100 to 115°C.

[0096] <Functional layer> The functional layer includes either or both of polyamide (PA) and ethylene-vinyl alcohol copolymer (EVOH). The functional layer containing polyamide imparts to the laminate film a function of protecting the laminate film itself and an appropriate oxygen barrier property. The functional layer containing the ethylene-vinyl alcohol copolymer imparts excellent oxygen barrier properties to the laminated film.

[0097] In the functional layer, the ratio of the total content of one or more components contained in the functional layer, which will be described later, to the total mass of the functional layer does not exceed 100 mass %. Similarly, in the composition for forming a functional layer described below, the ratio of the total content of one or more of the components contained in the composition for forming a functional layer described below to the total mass of the composition for forming a functional layer does not exceed 100 mass%.

[0098] Examples of the polyamide contained in the functional layer include polyamides obtained by polymerizing or copolymerizing nylon salts obtained by reacting cyclic lactams (lactams having 3 or more ring members), amino acids, or diamines with dicarboxylic acids.

[0099] Examples of the cyclic lactam include ε-caprolactam, ω-enantholactam, ω-laurolactam, α-pyrrolidone, and α-piperidone.

[0100] Examples of the amino acid include 6-aminocaproic acid, 7-aminoheptanoic acid, 9-aminononanoic acid, 11-aminoundecanoic acid, and 12-aminododecanoic acid.

[0101] Examples of the diamine that forms the nylon salt include aliphatic amines such as tetramethylenediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, decamethylenediamine, undecamethylenediamine, dodecamethylenediamine, 2,2,4-trimethylhexamethylenediamine, and 2,4,4-trimethylhexamethylenediamine; Alicyclic diamines such as 1,3-bis(aminomethyl)cyclohexane, 1,4-bis(aminomethyl)cyclohexane, isophoronediamine, piperazine, bis(4-aminocyclohexyl)methane, and 2,2-bis-(4-aminocyclohexyl)propane; Examples of the diamine include aromatic diamines such as metaxylylenediamine and paraxylylenediamine.

[0102] Examples of the dicarboxylic acid that forms the nylon salt include aliphatic dicarboxylic acids such as glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sepatic acid, undecanedioic acid, and dodecanedioic acid; Alicyclic carboxylic acids such as hexahydroterephthalic acid and hexahydroisophthalic acid; Examples of aromatic dicarboxylic acids include terephthalic acid, isophthalic acid, 1,2-naphthalenedicarboxylic acid, 1,3-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 1,6-naphthalenedicarboxylic acid, 1,7-naphthalenedicarboxylic acid, 1,8-naphthalenedicarboxylic acid, 2,3-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, and 2,7-naphthalenedicarboxylic acid.

[0103] More specifically, the polyamide contained in the functional layer includes, for example, 4-nylon, 6-nylon, 7-nylon, 11-nylon, 12-nylon, 46-nylon, 66-nylon, 69-nylon, 610-nylon, 611-nylon, 612-nylon, 6T-nylon, 6I nylon, a copolymer of 6-nylon and 66-nylon (nylon 6 / 66), a copolymer of 6-nylon and 610-nylon, a copolymer of 6-nylon and 611-nylon, a copolymer of 6-nylon and 12-nylon (nylon 6 / 12), a copolymer of 6-nylon and 612 nylon, copolymers of 6-nylon and 6T-nylon, copolymers of 6-nylon and 6I-nylon, copolymers of 6-nylon, 66-nylon and 610-nylon, copolymers of 6-nylon, 66-nylon and 12-nylon (nylon 6 / 66 / 12), copolymers of 6-nylon, 66-nylon and 612-nylon, copolymers of 66-nylon and 6T-nylon, copolymers of 66-nylon and 6I-nylon, copolymers of 6T-nylon and 6I-nylon, copolymers of 66-nylon, 6T-nylon and 6I-nylon, and copolymers of 66-nylon, 6T-nylon and 6I-nylon.

[0104] The polyamide contained in the functional layer is preferably 6-nylon, 12-nylon, 66-nylon, nylon 6 / 66, nylon 6 / 12 or nylon 6 / 66 / 12 in terms of heat resistance, mechanical strength, availability, and the like.

[0105] In the ethylene-vinyl alcohol copolymer contained in the functional layer, the ratio of the amount (mol) of structural units derived from ethylene to the total amount (mol) of structural units (sometimes referred to in this specification as the "copolymerization ratio of ethylene") may be 80 mol% or less, but is preferably 50 mol% or less, and may be, for example, any one of 45 mol% or less, 40 mol% or less, 35 mol% or less, and 30 mol% or less. When the ratio (copolymerization ratio of ethylene) is 50 mol% or less, the ratio of the amount (mol) of structural units considered to be derived from vinyl alcohol becomes high, and the oxygen barrier property of the laminated film becomes higher. On the other hand, the lower limit of the ratio (mol) of the amount of the structural unit derived from ethylene (the copolymerization ratio of the ethylene) is not particularly limited. For example, an ethylene-vinyl alcohol copolymer having the ratio (the copolymerization ratio of the ethylene) of 25 mol% or more can be more easily obtained or produced. In one embodiment, the ratio of the amount (mol) of the structural units derived from ethylene (the copolymerization ratio of ethylene) is preferably 25 to 50 mol%, and may be, for example, any one of 25 to 45 mol%, 25 to 40 mol%, 25 to 35 mol%, and 25 to 30 mol% or less. However, these are just examples of the ratio (the copolymerization ratio of ethylene).

[0106] The functional layer may or may not contain other components that are neither polyamide nor ethylene-vinyl alcohol copolymer, as long as the effects of the present invention are not impaired. The other components contained in the functional layer may be either resin components (sometimes referred to in this specification as "other resin components") or non-resin components (sometimes referred to in this specification as "other non-resin components").

[0107] The other resin component contained in the functional layer is not particularly limited as long as it is a resin that does not fall into the category of either polyamide or ethylene-vinyl alcohol copolymer. Examples of the other non-resin components contained in the functional layer include the same non-resin components as those contained in the inner layer.

[0108] The functional layer may contain only one type of other component, or two or more types. When there are two or more types, the combination and ratio thereof can be arbitrarily selected depending on the purpose.

[0109] In the functional layer, the ratio of the combined content of polyamide and ethylene-vinyl alcohol copolymer to the total mass of the functional layer (([polyamide content in functional layer (parts by mass)] + [ethylene-vinyl alcohol copolymer content in functional layer (parts by mass)]) / [total mass of functional layer (parts by mass)] × 100) is preferably 90 to 100 mass%, more preferably 95 to 100 mass%, and may be, for example, any of 97 to 100 mass% and 99 to 100 mass%. When the ratio is equal to or greater than the lower limit, the effect obtained by the functional layer containing polyamide or ethylene-vinyl alcohol copolymer is enhanced. The above ratio is usually the same as the ratio of the total content of polyamide and ethylene-vinyl alcohol copolymer to the total content (parts by mass) of components that do not vaporize at room temperature in the composition for forming a functional layer described below (([content of polyamide in the composition for forming a functional layer (parts by mass)] + [content of ethylene-vinyl alcohol copolymer in the composition for forming a functional layer (parts by mass)]) / [total content of components that do not vaporize at room temperature in the composition for forming a functional layer (parts by mass)] × 100). Here, when the functional layer or the composition for forming a functional layer does not contain a polyamide, the content of the polyamide in the functional layer or the composition for forming a functional layer is 0 parts by mass.When the functional layer or the composition for forming a functional layer does not contain an ethylene-vinyl alcohol copolymer, the content of the ethylene-vinyl alcohol copolymer in the functional layer or the composition for forming a functional layer is 0 parts by mass.

[0110] The functional layer may be one layer (single layer) or two or more layers. When the functional layer is made up of multiple layers, these multiple layers may be the same or different from each other, and the combination of these multiple layers is not particularly limited as long as it does not impair the effects of the present invention.

[0111] The laminated film includes, as a functional layer, a functional layer (a) and no functional layer (b), or includes the functional layer (a) and the functional layer (b) provided in direct contact with one surface of the functional layer (a), The functional layer (a) comprises the polyamide, The functional layer (b) preferably contains the ethylene-vinyl alcohol copolymer. In the functional layer (a), it is preferable that the content ratio of the polyamide to the total mass of the functional layer (a) is 90 to 100 mass%, and the content ratio of the ethylene-vinyl alcohol copolymer to the total mass of the functional layer (a) is 0 to 5 mass%. In the functional layer (b), it is preferable that the content ratio of the polyamide to the total mass of the functional layer (b) is 0 to 5 mass%, and the content ratio of the ethylene-vinyl alcohol copolymer to the total mass of the functional layer (b) is 90 to 100 mass%. When the laminated film comprises the functional layer (a) and the functional layer (b), it is preferable that the laminated film comprises the functional layer (b) and the functional layer (a) in this order in the direction from the inner layer to the adhesive layer.

[0112] The ratio of the thickness of the functional layer to the thickness of the laminated film ([thickness of functional layer] / [thickness of laminated film]×100) is preferably 5 to 60%, more preferably 10 to 30%, and may be, for example, any of 10 to 25% and 15 to 30%. When the ratio is equal to or more than the lower limit, the effect obtained by the laminated film having a functional layer is enhanced. When the ratio is equal to or less than the upper limit, the thickness of the functional layer is prevented from becoming excessive. For example, the effect obtained by the laminated film having a layer other than the functional layer (e.g., an inner layer, an adhesive layer) is enhanced.

[0113] The thickness of the functional layer is preferably from 2.5 to 120 μm, more preferably from 5 to 60 μm, and may be, for example, any one of 5 to 25 μm, 15 to 45 μm, and 35 to 60 μm. When the functional layer is made up of a plurality of layers, the total thickness of these layers is preferably within the above numerical range.

[0114] <Outer layer> When the laminate film of this embodiment further includes an outer layer provided on the side of the functional layer opposite the adhesive layer, the outer layer enhances protection of the components of the laminate film other than the outer layer. The outer layer is preferably a resin layer containing a resin. Examples of the resin contained in the outer layer include polyethylene (PE), polypropylene (PP), and polyamide (PA).

[0115] In the outer layer, the ratio of the total content of one or more components contained in the outer layer, which will be described later, to the total mass of the outer layer does not exceed 100 mass %. Similarly, in the composition for forming an outer layer described later, the ratio of the total content of one or more components contained in the composition for forming an outer layer described later to the total mass of the composition for forming an outer layer does not exceed 100 mass%.

[0116] The polyethylene contained in the outer layer may be the same as the polyethylene contained in the inner layer. For example, the Vicat softening temperature, melting point and melt flow rate of the polyethylene contained in the outer layer are preferably similar to the Vicat softening temperature, melting point and melt flow rate of the polyethylene contained in the inner layer, respectively.

[0117] For example, the Vicat softening temperature of the polyethylene contained in the outer layer is preferably 90° C. or higher, more preferably 100° C. or higher, and even more preferably 110° C. or higher. When the Vicat softening temperature is equal to or higher than the lower limit, fusion between the package and an object in contact with the package can be suppressed when the package obtained using the laminate film is heated. On the other hand, the upper limit of the Vicat softening temperature is not particularly limited. For example, polyethylene having a Vicat softening temperature of 130° C. or lower is more easily available or produced. In one embodiment, the Vicat softening temperature of the polyethylene contained in the outer layer may be, for example, any one of 90 to 130° C., 100 to 130° C., and 110 to 130° C. However, these are only examples of the Vicat softening temperature.

[0118] Similarly, the melting point of the polyethylene contained in the outer layer is preferably 110 to 130° C., more preferably 120 to 130° C., and even more preferably 125 to 130° C. When the melting point of the polyethylene is equal to or higher than the lower limit, when a package obtained using the laminated film is heated, fusion between the package and an object in contact with the package can be suppressed. When the melting point of the polyethylene is equal to or lower than the upper limit, the transparency of the laminated film and the package obtained using the same is increased. Similarly, the melt flow rate of the polyethylene contained in the outer layer is preferably 6 g / 10 min or less, more preferably 5 g / 10 min or less, and even more preferably 4 g / 10 min or less. When the melt flow rate of the polyethylene is equal to or less than the upper limit, the variation in thickness of the outer layer is reduced, and the shape of the outer layer is more stable. On the other hand, polyethylene with an MFR of 2 g / 10 min or more can be more easily obtained or produced.

[0119] In terms of improving the properties of the outer layer, the polyethylene contained in the outer layer is preferably one or more types selected from the group consisting of low-density polyethylene, linear low-density polyethylene, and metallocene-catalyzed linear low-density polyethylene, and more preferably one or both of linear low-density polyethylene and metallocene-catalyzed linear low-density polyethylene.

[0120] Examples of the polypropylene contained in the outer layer include homopolypropylene (hPP), propylene-ethylene random copolymer (also known as polypropylene random copolymer (rPP)), and propylene-ethylene block copolymer (also known as polypropylene block copolymer (bPP)). The polypropylene contained in the outer layer is preferably homopolypropylene.

[0121] The polyamide contained in the outer layer may be the same as the polyamide contained in the functional layer.

[0122] The outer layer may contain only one type of resin, or two or more types. When two or more types are contained, the combination and ratio thereof can be arbitrarily selected depending on the purpose.

[0123] The outer layer preferably contains one or more materials selected from the group consisting of polyethylene, polypropylene, and polyamide, which enhances the above-mentioned effects of the outer layer. In particular, in terms of improving the properties of the outer layer, it is more preferable that the outer layer contains polyethylene, even more preferable that it contains one or more types selected from the group consisting of low-density polyethylene, linear low-density polyethylene, and metallocene-catalyzed linear low-density polyethylene, and it is particularly preferable that it contains either one or both of linear low-density polyethylene and metallocene-catalyzed linear low-density polyethylene.

[0124] The outer layer may or may not contain other components that do not fall into the category of polyethylene, polypropylene, or polyamide, as long as the effects of the present invention are not impaired. The other components contained in the outer layer may be either resin components (sometimes referred to in this specification as "other resin components") or non-resin components (sometimes referred to in this specification as "other non-resin components").

[0125] The other resin component contained in the outer layer is not particularly limited as long as it is a resin that does not fall into the category of polyethylene, polypropylene, or polyamide. Examples of the other non-resin components contained in the outer layer include the same non-resin components as those contained in the inner layer.

[0126] The outer layer may contain only one type of other component, or two or more types. When there are two or more types, the combination and ratio thereof can be arbitrarily selected depending on the purpose.

[0127] In the outer layer, the ratio of the total content of polyethylene, polypropylene, and polyamide to the total mass of the outer layer (([polyethylene content of outer layer (parts by mass)]+[polypropylene content of outer layer (parts by mass)]+[polyamide content of outer layer (parts by mass)]) / [total mass of outer layer (parts by mass)]×100) is preferably 90 to 100% by mass, more preferably 95 to 100% by mass, and may be, for example, any of 97 to 100% by mass and 99 to 100% by mass. When the ratio is equal to or greater than the lower limit, the effect obtained by the outer layer containing polyethylene, polypropylene, or polyamide is further enhanced. The above ratio is usually the same as the ratio of the total content of polyethylene, polypropylene, and polyamide to the total content (parts by mass) of components that do not vaporize at room temperature in the composition for forming an outer layer described below (([content of polyethylene in the composition for forming an outer layer (parts by mass)] + [content of polypropylene in the composition for forming an outer layer (parts by mass)] + [content of polyamide in the composition for forming an outer layer (parts by mass)]) / [total content of components that do not vaporize at room temperature in the composition for forming an outer layer (parts by mass)] × 100). Here, when the outer layer or composition for forming an outer layer does not contain polyethylene, the polyethylene content of the outer layer or composition for forming an outer layer is 0 parts by mass. When the outer layer or composition for forming an outer layer does not contain polypropylene, the polypropylene content of the outer layer or composition for forming an outer layer is 0 parts by mass. When the outer layer or composition for forming an outer layer does not contain polyamide, the polyamide content of the outer layer or composition for forming an outer layer is 0 parts by mass.

[0128] When the outer layer contains polyethylene, the ratio of the total content of the linear low density polyethylene and the metallocene-catalyzed linear low density polyethylene to the polyethylene content in the outer layer (([linear low density polyethylene content in outer layer (parts by mass)]+[metallocene-catalyzed linear low density polyethylene content in outer layer (parts by mass)]) / [polyethylene content in outer layer (parts by mass)]×100) is preferably 80% by mass or more, more preferably 90% by mass or more, and may be, for example, any one of 95% by mass or more, 97% by mass or more, and 99% by mass or more. When the ratio is equal to or more than the lower limit, the effect obtained by the outer layer containing the linear low density polyethylene or the metallocene-catalyzed linear low density polyethylene is further enhanced. On the other hand, the proportion is 100% by mass or less. The above ratio is usually the same as the ratio of the total content (parts by mass) of the linear low-density polyethylene and the metallocene-catalyzed linear low-density polyethylene to the polyethylene content (parts by mass) in the composition for forming an outer layer described below (([content (parts by mass) of linear low-density polyethylene in the composition for forming an outer layer)] + [content (parts by mass) of metallocene-catalyzed linear low-density polyethylene in the composition for forming an outer layer)]) / [content (parts by mass) of polyethylene in the composition for forming an outer layer)] × 100). Here, when the outer layer or the composition for forming an outer layer does not contain a linear low density polyethylene, the content of the linear low density polyethylene in the outer layer or the composition for forming an outer layer is 0 part by mass. When the outer layer or the composition for forming an outer layer does not contain a metallocene-catalyzed linear low density polyethylene, the content of the metallocene-catalyzed linear low density polyethylene in the outer layer or the composition for forming an outer layer is 0 part by mass.

[0129] The outer layer may be one layer (single layer) or two or more layers. When the outer layer is made of multiple layers, these multiple layers may be the same or different from each other, and the combination of these multiple layers is not particularly limited as long as it does not impair the effects of the present invention. The outer layer preferably consists of one layer (single layer).

[0130] When the laminated film has an outer layer, the ratio of the thickness of the outer layer to the thickness of the laminated film ([thickness of outer layer] / [thickness of laminated film]×100) is preferably 10 to 40%, more preferably 10 to 30%, and may be, for example, any of 10 to 20%, 15 to 25%, and 20 to 30%. When the ratio is equal to or more than the lower limit, the effect obtained by the laminated film having an outer layer is enhanced. When the ratio is equal to or less than the upper limit, the thickness of the outer layer is prevented from becoming excessive. For example, the effect obtained by the laminated film having a layer other than the outer layer (for example, an inner layer, a functional layer, an adhesive layer) is enhanced.

[0131] The thickness of the outer layer is preferably from 5 to 80 μm, more preferably from 5 to 60 μm, and may be, for example, any one of from 5 to 25 μm, 20 to 45 μm, and 40 to 60 μm. When the outer layer is made up of a plurality of layers, the total thickness of these layers is preferably within the above-mentioned numerical range.

[0132] <Middle layer (second middle layer)> When the laminate film of the present embodiment further includes an intermediate layer provided between the outer layer and the functional layer, the intermediate layer imparts additional functionality to the laminate film. For example, when an intermediate layer is provided adjacent to (in contact with) an outer layer on the inner layer side, the intermediate layer can have a function equivalent to that of the outer layer, or can have a function that the outer layer does not have. As described above, when the laminated film of this embodiment has a first intermediate layer provided between the inner layer and the functional layer, the intermediate layer provided between the outer layer and the functional layer is referred to as the second intermediate layer.

[0133] The intermediate layer (second intermediate layer) is preferably a resin layer containing a resin. The resin contained in the intermediate layer may be, for example, polyethylene (PE).

[0134] In the intermediate layer, the ratio of the total content of one or more components contained in the intermediate layer, which will be described later, to the total mass of the intermediate layer does not exceed 100 mass %. Similarly, in the composition for forming an intermediate layer described below, the ratio of the total content of one or more of the components contained in the composition for forming an intermediate layer described below to the total mass of the composition for forming an intermediate layer does not exceed 100 mass%.

[0135] The polyethylene contained in the intermediate layer may be the same as the polyethylene contained in the inner layer. For example, the Vicat softening temperature, melting point and melt flow rate of the polyethylene contained in the intermediate layer are preferably similar to the Vicat softening temperature, melting point and melt flow rate of the polyethylene contained in the inner layer, respectively.

[0136] For example, the Vicat softening temperature of the polyethylene contained in the intermediate layer is preferably 90° C. or higher, and may be any one of 95° C. or higher, 100° C. or higher, and 110° C. or higher. When the Vicat softening temperature is equal to or higher than the lower limit, the effect of suppressing a decrease in the adhesive strength between adjacent layers therein when the laminated film or a package obtained using the laminated film is heated is enhanced. On the other hand, the upper limit of the Vicat softening temperature is not particularly limited. For example, polyethylene having a Vicat softening temperature of 130° C. or lower is more easily available or produced. In one embodiment, the Vicat softening temperature of the polyethylene contained in the intermediate layer may be, for example, any one of 90 to 130° C., 95 to 130° C., 100 to 130° C., and 110 to 130° C. However, these are only examples of the Vicat softening temperature.

[0137] Similarly, the melting point of the polyethylene contained in the intermediate layer is preferably 110 to 130°C, and may be, for example, any of 120 to 130°C and 125 to 130°C, or any of 110 to 120°C and 110 to 115°C. When the melting point of the polyethylene is equal to or higher than the lower limit, the effect of suppressing the decrease in adhesion strength between adjacent layers in the laminate film or the package obtained using the laminate film when the laminate film or the package obtained using the laminate film is heated is enhanced. When the melting point of the polyethylene is equal to or lower than the upper limit, the transparency of the laminate film and the package obtained using the laminate film is enhanced. Similarly, the melt flow rate of the polyethylene contained in the intermediate layer is preferably 6 g / 10 min or less, more preferably 5 g / 10 min or less, and even more preferably 4 g / 10 min or less. When the melt flow rate of the polyethylene is equal to or less than the upper limit, the variation in thickness of the intermediate layer is reduced, and the shape of the intermediate layer is more stable. On the other hand, polyethylene with an MFR of 2 g / 10 min or more can be more easily obtained or produced.

[0138] For example, in terms of improving the properties of the intermediate layer similar to those of the outer layer, the polyethylene contained in the intermediate layer is preferably one or more types selected from the group consisting of low-density polyethylene, linear low-density polyethylene, and metallocene-catalyzed linear low-density polyethylene, and more preferably one or both of linear low-density polyethylene and metallocene-catalyzed linear low-density polyethylene.

[0139] In particular, the polyethylene contained in the intermediate layer is preferably biomass-derived polyethylene, from the viewpoints of improving the properties of the intermediate layer similar to those of the outer layer, reducing the amount of petroleum resources used, and reducing carbon dioxide emissions during the production and disposal of the laminated film, thereby reducing the environmental load.

[0140] In this specification, not only in the case of polyethylene, but also in the case of a resin that is not specified as being derived from biomass, unless otherwise specified, it means a resin that is not derived from biomass.

[0141] The biomass-derived polyethylene may be, for example, polyethylene derived from plants such as carbon-neutral sugar cane. Examples of the biomass-derived polyethylene include low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), metallocene-catalyzed linear low-density polyethylene (metallocene LLDPE), medium-density polyethylene (MDPE), and high-density polyethylene (HDPE).

[0142] The polyethylene contained in the intermediate layer is more preferably one or more types selected from the group consisting of biomass-derived low-density polyethylene, biomass-derived linear low-density polyethylene, and biomass-derived metallocene-catalyzed linear low-density polyethylene, and even more preferably one or both of the biomass-derived linear low-density polyethylene and the biomass-derived metallocene-catalyzed linear low-density polyethylene.

[0143] The intermediate layer may or may not contain other components that do not fall under the category of polyethylene, as long as the effects of the present invention are not impaired. The other components contained in the intermediate layer may be either resin components (sometimes referred to in this specification as "other resin components") or non-resin components (sometimes referred to in this specification as "other non-resin components").

[0144] The other resin component contained in the intermediate layer is not particularly limited as long as it is a resin other than polyethylene. Examples of the other non-resin components contained in the intermediate layer include the same non-resin components as those contained in the inner layer.

[0145] The intermediate layer may contain only one type of other component, or two or more types. When there are two or more types, the combination and ratio thereof can be arbitrarily selected depending on the purpose.

[0146] In the intermediate layer, the ratio of the polyethylene content to the total mass of the intermediate layer ([polyethylene content of intermediate layer (parts by mass)] / [total mass of intermediate layer (parts by mass)]×100) is preferably 90 to 100% by mass, more preferably 95 to 100% by mass, and may be, for example, any one of 97 to 100% by mass and 99 to 100% by mass. When the ratio is equal to or greater than the lower limit, the effect obtained by the intermediate layer containing polyethylene is enhanced. The above ratio is usually the same as the ratio of the polyethylene content to the total content (parts by mass) of components that do not vaporize at room temperature in the composition for forming an intermediate layer described below ([polyethylene content (parts by mass) in the composition for forming an intermediate layer)] / [total content (parts by mass) of components that do not vaporize at room temperature in the composition for forming an intermediate layer)] × 100).

[0147] In the intermediate layer, the ratio of the total content of linear low density polyethylene and metallocene-catalyzed linear low density polyethylene to the polyethylene content (([linear low density polyethylene content in intermediate layer (parts by mass)] + [metallocene-catalyzed linear low density polyethylene content in intermediate layer (parts by mass)]) / [polyethylene content in intermediate layer (parts by mass)] × 100) is preferably 80 mass% or more, more preferably 90 mass% or more, and may be, for example, any of 95 mass% or more, 97 mass% or more, and 99 mass% or more. When the ratio is equal to or more than the lower limit, the effect obtained by the intermediate layer containing linear low density polyethylene or metallocene-catalyzed linear low density polyethylene is further enhanced. On the other hand, the proportion is 100% by mass or less. The above ratio is usually the same as the ratio of the total content (parts by mass) of the linear low density polyethylene and the metallocene-catalyzed linear low density polyethylene to the polyethylene content (parts by mass) in the composition for forming an intermediate layer described below (([linear low density polyethylene content (parts by mass) in the composition for forming an intermediate layer)] + [metallocene-catalyzed linear low density polyethylene content (parts by mass) in the composition for forming an intermediate layer)]) / [polyethylene content (parts by mass) in the composition for forming an intermediate layer)] × 100). Here, when the intermediate layer or the composition for forming an intermediate layer does not contain linear low density polyethylene, the content of linear low density polyethylene in the intermediate layer or the composition for forming an intermediate layer is 0 part by mass. When the intermediate layer or the composition for forming an intermediate layer does not contain metallocene-catalyzed linear low density polyethylene, the content of metallocene-catalyzed linear low density polyethylene in the intermediate layer or the composition for forming an intermediate layer is 0 part by mass.

[0148] When the intermediate layer contains biomass-derived polyethylene, the ratio of the content of biomass-derived polyethylene in the intermediate layer to the content of polyethylene (more specifically, the total content of non-biomass-derived polyethylene and biomass-derived polyethylene) ([content of biomass-derived polyethylene in intermediate layer (parts by mass)] / ([content of non-biomass-derived polyethylene in intermediate layer (parts by mass)]+[content of biomass-derived polyethylene in intermediate layer (parts by mass)])×100) may be, for example, any one of 10% by mass or more, 30% by mass or more, 50% by mass or more, 70% by mass or more, and 90% by mass or more. The higher the ratio, the greater the effect of reducing the environmental load of the laminated film. On the other hand, the proportion is 100% by mass or less. The above ratio is usually the same as the ratio of the content of biomass-derived polyethylene to the content of polyethylene (parts by mass) in the composition for forming an intermediate layer described below ([content of biomass-derived polyethylene in the composition for forming an intermediate layer (parts by mass)] / ([content of non-biomass-derived polyethylene in the composition for forming an intermediate layer (parts by mass)]+[content of biomass-derived polyethylene in the intermediate layer (parts by mass)])×100). Here, when the intermediate layer or the composition for forming an intermediate layer does not contain any part of a component corresponding to biomass-derived polyethylene, the content of that component in the intermediate layer or the composition for forming an intermediate layer is 0 parts by mass.

[0149] The intermediate layer may be one layer (single layer) or two or more layers. When the intermediate layer is made up of multiple layers, these multiple layers may be the same or different from each other, and the combination of these multiple layers is not particularly limited as long as it does not impair the effects of the present invention. The intermediate layer preferably consists of one layer (single layer).

[0150] When the laminated film has an intermediate layer, the ratio of the thickness of the intermediate layer to the thickness of the laminated film ([thickness of intermediate layer] / [thickness of laminated film]×100) is preferably 5 to 30%, more preferably 9 to 19%, and may be, for example, any of 9 to 12%, 8 to 16%, and 15 to 30%. When the ratio is equal to or more than the lower limit, the effect obtained by the laminated film having an intermediate layer is enhanced. When the ratio is equal to or less than the upper limit, the thickness of the intermediate layer is prevented from becoming excessive. For example, the effect obtained by the laminated film having a layer other than the intermediate layer (for example, an inner layer, a functional layer, an adhesive layer, an outer layer) is enhanced.

[0151] The thickness of the intermediate layer is preferably from 2.5 to 60 μm, more preferably from 4.5 to 38 μm, and may be, for example, any one of 4.5 to 15 μm, 12 to 23 μm, and 20 to 38 μm. When the intermediate layer is made up of a plurality of layers, the total thickness of these layers is preferably within the above numerical range.

[0152] <Combination of outer layer and middle layer (second middle layer)> When the laminated film of the present embodiment has one or more outer layers and one or more intermediate layers, It is preferred that the outer layer comprises a non-biomass-derived polyethylene and the intermediate layer comprises a biomass-derived polyethylene; It is more preferable that the outer layer contains one or more selected from the group consisting of non-biomass-derived low-density polyethylene, non-biomass-derived linear low-density polyethylene, and non-biomass-derived metallocene-catalyzed linear low-density polyethylene, and the intermediate layer contains one or more selected from the group consisting of biomass-derived low-density polyethylene, biomass-derived linear low-density polyethylene, and biomass-derived metallocene-catalyzed linear low-density polyethylene, It is further preferred that the outer layer comprises either one or both of a non-biomass-derived linear low density polyethylene and a non-biomass-derived metallocene-catalyzed linear low density polyethylene, and the intermediate layer comprises either one or both of a biomass-derived linear low density polyethylene and a biomass-derived metallocene-catalyzed linear low density polyethylene, When the laminated film has two or more outer layers, it is preferable that all of the outer layers are outer layers containing the above-mentioned non-biomass-derived polyethylene, and when the laminated film has two or more intermediate layers, it is preferable that all of the intermediate layers are intermediate layers containing the above-mentioned biomass-derived polyethylene.

[0153] <Outer adhesive layer> When the laminated film of the present embodiment further includes an outer adhesive layer provided on the side of the functional layer opposite to the inner layer side, the outer adhesive layer bonds the two adjacent layers together. For example, the outer adhesive layer provided between the intermediate layer and the functional layer bonds the intermediate layer and the functional layer together. The outer adhesive layer includes an adhesive resin.

[0154] The adhesive resin contained in the outer adhesive layer preferably has a Vicat softening temperature of 65° C. or higher, and may be, for example, 75° C. or higher. On the other hand, the upper limit of the Vicat softening temperature of the adhesive resin contained in the outer adhesive layer is not particularly limited. For example, polyethylene having a Vicat softening temperature of 115° C. or less is more easily available or produced. In one embodiment, the Vicat softening temperature of the adhesive resin contained in the outer adhesive layer may be, for example, any one of 65 to 115° C. and 75 to 115° C. However, these are only examples of the Vicat softening temperature of the adhesive resin contained in the outer adhesive layer.

[0155] The melt flow rate (MFR) of the adhesive resin contained in the outer adhesive layer is preferably 1 to 6 g / 10 min, more preferably 2 to 5 g / 10 min. When the MFR of the adhesive resin contained in the outer adhesive layer is equal to or higher than the lower limit, the flowability of the outer adhesive layer during processing of the laminated film is good, and the appearance of the laminated film and the package obtained using the same is improved. When the MFR of the adhesive resin contained in the outer adhesive layer is equal to or lower than the upper limit, the thickness variation of the outer adhesive layer is reduced, and the shape of the outer adhesive layer is more stable.

[0156] The density of the adhesive resin contained in the outer adhesive layer is 0.9 to 0.93 g / cm 3 and preferably 0.9 to 0.92 g / cm 3 It is more preferable that the density of the adhesive resin contained in the outer adhesive layer is equal to or higher than the lower limit, the stretchability of the laminated film during deep drawing is more stable, and the density of the adhesive resin contained in the outer adhesive layer is equal to or lower than the upper limit, the transparency of the laminated film and the package obtained using the same is higher.

[0157] The melting point of the adhesive resin contained in the outer adhesive layer is preferably 110 to 130°C, more preferably 115 to 125°C. When the melting point of the adhesive resin contained in the outer adhesive layer is equal to or higher than the lower limit, the effect of suppressing the decrease in adhesion strength between adjacent layers in the laminate film or the package obtained using the laminate film when the laminate film or the package obtained using the laminate film is heated is enhanced. When the melting point of the adhesive resin contained in the outer adhesive layer is equal to or lower than the upper limit, the transparency of the laminate film and the package obtained using the laminate film is enhanced.

[0158] The outer adhesive layer has the same configuration and arrangement as the adhesive layer described above, except that the adhesive resin contained therein may have a different Vicat softening temperature, melt flow rate, density or melting point as described above. Therefore, the outer adhesive layer will not be described in further detail.

[0159] <First middle class> When the laminate film of this embodiment further includes a first intermediate layer provided between the inner layer and the adhesive layer, the first intermediate layer imparts additional functionality to the laminate film. For example, when the first intermediate layer is disposed adjacent to (in contact with) the inner layer on the functional layer side, the first intermediate layer can have a function similar to that of the inner layer, or it can have a function that the inner layer does not have.

[0160] The first intermediate layer is preferably a resin layer containing a resin. The resin contained in the first intermediate layer may be, for example, polyethylene (PE).

[0161] The first intermediate layer has the same configuration and arrangement as the second intermediate layer, except for its location. For example, a preferred example of the first intermediate layer includes a biomass-derived polyethylene having a Vicat softening temperature of 90° C. or higher. Therefore, a further detailed description of the first intermediate layer will be omitted.

[0162] <Combination of inner layer and first middle layer> When the laminated film of the present embodiment includes one or more of the inner layers and one or more of the first intermediate layers, It is preferred that the inner layer contains a non-biomass-derived polyethylene and the first intermediate layer contains a biomass-derived polyethylene; It is more preferable that the inner layer contains one or more selected from the group consisting of non-biomass-derived low-density polyethylene, non-biomass-derived linear low-density polyethylene, and non-biomass-derived metallocene-catalyzed linear low-density polyethylene, and the first intermediate layer contains one or more selected from the group consisting of biomass-derived low-density polyethylene, biomass-derived linear low-density polyethylene, and biomass-derived metallocene-catalyzed linear low-density polyethylene, It is further preferred that the inner layer comprises either one or both of a non-biomass-derived linear low density polyethylene and a non-biomass-derived metallocene-catalyzed linear low density polyethylene, and the first intermediate layer comprises either one or both of a biomass-derived linear low density polyethylene and a biomass-derived metallocene-catalyzed linear low density polyethylene, When the laminated film has two or more inner layers, it is preferable that all of the inner layers are inner layers containing the above-mentioned non-biomass-derived polyethylene, and when the laminated film has two or more first intermediate layers, it is preferable that all of the first intermediate layers are first intermediate layers containing the above-mentioned biomass-derived polyethylene.

[0163] <Other layers> The laminate film of this embodiment may have other layers that do not fall into any of the inner layer, adhesive layer, functional layer, first intermediate layer, outer adhesive layer, second intermediate layer, and outer layer, as long as the effects of the present invention are not impaired, but it is preferable that the laminate film does not have any of the other layers. Since the laminated film of this embodiment does not have the other layers, when the above-mentioned package is heat-treated, the effect of suppressing tearing of the package is greater at the above-mentioned heat-sealed areas, particularly the protruding heat-sealed areas.

[0164] <Overall structure of laminated film> The thickness (total thickness) of the laminate film of this embodiment is not particularly limited, but is preferably 30 to 300 μm, more preferably 40 to 250 μm, and even more preferably 50 to 200 μm. When the thickness of the laminate film is equal to or greater than the lower limit, the strength of the laminate film is increased. When the thickness of the laminate film is equal to or less than the upper limit, the laminate film can be made thinner, and the formability of the laminate film is increased.

[0165] In the laminated film, it is preferable that all layers constituting the laminated film (e.g., inner layer, adhesive layer, functional layer, first intermediate layer, outer adhesive layer, second intermediate layer, outer layer) are unstretched layers (films). Such unstretched laminated films are particularly excellent in formability and are particularly suitable for producing, for example, base materials for constituting packaging bodies.

[0166] In the laminate film, it is preferable that all layers constituting the laminate film (e.g., inner layer, adhesive layer, functional layer, first intermediate layer, outer adhesive layer, second intermediate layer, outer layer) have transparency, so that the laminate film has transparency, i.e., the laminate film is a transparent laminate film. In a package obtained using such a laminate film, the packaged item can be easily visually confirmed through the laminate film or its molded body.

[0167] In the laminate film, the total value of the ratio of the thickness of the inner layer to the thickness of the laminate film, the ratio of the thickness of the adhesive layer to the thickness of the laminate film, the ratio of the thickness of the functional layer to the thickness of the laminate film, and the ratio of the thickness of other layers (layers that do not fall into the category of an inner layer, an adhesive layer, or a functional layer) to the thickness of the laminate film does not exceed 100%.

[0168] An example of a preferred laminate film of the present embodiment is A laminated film for producing a package in which a food product containing a liquid is packaged and for heat-treating the package, comprising: The laminated film includes an inner layer, an adhesive layer, and a functional layer, and the inner layer and the functional layer are bonded to each other by the adhesive layer. The inner layer contains, as the polyethylene, either or both of a linear low density polyethylene and a metallocene-catalyzed linear low density polyethylene, The functional layer contains either one or both of a polyamide and an ethylene-vinyl alcohol copolymer, the adhesive layer contains, as an adhesive resin, an acid-modified polyolefin having an acidic group, The adhesive resin has a Vicat softening temperature of 90° C. or higher; The laminated film includes, as the functional layer, a functional layer (a) and no functional layer (b), or includes the functional layer (a) and a functional layer (b) provided in direct contact with one surface of the functional layer (a), the functional layer (a) containing the polyamide and the functional layer (b) containing the ethylene-vinyl alcohol copolymer, and when the laminated film includes the functional layer (a) and the functional layer (b), the laminated film includes the functional layer (b) and the functional layer (a) in this order in the direction from the inner layer to the adhesive layer, When the thickness of the inner layer is 45 μm or less, the Vicat softening temperature of the adhesive resin is 105 to 115° C., when the thickness of the inner layer is 40 to 75 μm, the Vicat softening temperature of the adhesive resin is either 95 to 115° C. or 100 to 115° C., and when the thickness of the inner layer is 70 μm or more, the Vicat softening temperature of the adhesive resin is either 90 to 115° C., 95 to 115° C., or 100 to 115° C.

[0169] As a more preferred example of the laminated film of this embodiment, A laminated film for producing a package in which a food product containing a liquid is packaged and for heat-treating the package, comprising: The laminated film includes an inner layer, an adhesive layer, and a functional layer, and the inner layer and the functional layer are bonded to each other by the adhesive layer. The inner layer contains, as the polyethylene, either or both of a linear low density polyethylene and a metallocene-catalyzed linear low density polyethylene, The functional layer contains either one or both of a polyamide and an ethylene-vinyl alcohol copolymer, the adhesive layer contains, as an adhesive resin, an acid-modified polyolefin having an acidic group, The adhesive resin has a Vicat softening temperature of 90° C. or higher; in the inner layer, a ratio of a total content of the linear low density polyethylene and the metallocene-catalyzed linear low density polyethylene to a content of the polyethylene is 80 to 100 mass%, In the functional layer, a ratio of a total content of the polyamide and the ethylene-vinyl alcohol copolymer to a total mass of the functional layer is 90 to 100 mass%, In the adhesive layer, the ratio of the content of the modified polyolefin to the content of the adhesive resin is 80 to 100 mass %, The laminated film includes, as the functional layer, a functional layer (a) and no functional layer (b), or includes the functional layer (a) and a functional layer (b) provided in direct contact with one surface of the functional layer (a), the functional layer (a) containing the polyamide and the functional layer (b) containing the ethylene-vinyl alcohol copolymer, and when the laminated film includes the functional layer (a) and the functional layer (b), the laminated film includes the functional layer (b) and the functional layer (a) in this order in the direction from the inner layer to the adhesive layer, When the thickness of the inner layer is 45 μm or less, the Vicat softening temperature of the adhesive resin is 105 to 115° C., when the thickness of the inner layer is 40 to 75 μm, the Vicat softening temperature of the adhesive resin is either 95 to 115° C. or 100 to 115° C., and when the thickness of the inner layer is 70 μm or more, the Vicat softening temperature of the adhesive resin is either 90 to 115° C., 95 to 115° C., or 100 to 115° C.

[0170] Other preferred examples of the laminate film of this embodiment include: A laminated film for producing a package in which a food product containing a liquid is packaged and for heat-treating the package, comprising: The laminated film includes an inner layer, an adhesive layer, and a functional layer, and the inner layer and the functional layer are bonded to each other by the adhesive layer. The laminated film further includes an outer layer provided on a surface of the functional layer opposite to the adhesive layer, The laminated film further includes an intermediate layer provided between the outer layer and the functional layer, The inner layer contains, as the polyethylene, either or both of a linear low density polyethylene and a metallocene-catalyzed linear low density polyethylene, The functional layer contains either one or both of a polyamide and an ethylene-vinyl alcohol copolymer, the adhesive layer contains, as an adhesive resin, an acid-modified polyolefin having an acidic group, The adhesive resin has a Vicat softening temperature of 90° C. or higher; The outer layer comprises one or more selected from the group consisting of polyethylene, polypropylene, and polyamide, The intermediate layer contains biomass-derived polyethylene as the polyethylene, The laminated film includes, as the functional layer, a functional layer (a) and no functional layer (b), or includes the functional layer (a) and a functional layer (b) provided in direct contact with one surface of the functional layer (a), the functional layer (a) containing the polyamide and the functional layer (b) containing the ethylene-vinyl alcohol copolymer, and when the laminated film includes the functional layer (a) and the functional layer (b), the laminated film includes the functional layer (b) and the functional layer (a) in this order in the direction from the inner layer to the adhesive layer, When the thickness of the inner layer is 45 μm or less, the Vicat softening temperature of the adhesive resin is 105 to 115° C., when the thickness of the inner layer is 40 to 75 μm, the Vicat softening temperature of the adhesive resin is either 95 to 115° C. or 100 to 115° C., and when the thickness of the inner layer is 70 μm or more, the Vicat softening temperature of the adhesive resin is either 90 to 115° C., 95 to 115° C., or 100 to 115° C.

[0171] A more preferred example of the laminated film of this embodiment is: A laminated film for producing a package in which a food product containing a liquid is packaged and for heat-treating the package, comprising: The laminated film includes an inner layer, an adhesive layer, and a functional layer, and the inner layer and the functional layer are bonded to each other by the adhesive layer. The laminated film further includes an outer layer provided on a surface of the functional layer opposite to the adhesive layer, The laminated film further includes an intermediate layer provided between the outer layer and the functional layer, The inner layer contains, as the polyethylene, either or both of a linear low density polyethylene and a metallocene-catalyzed linear low density polyethylene, The functional layer contains either one or both of a polyamide and an ethylene-vinyl alcohol copolymer, the adhesive layer contains, as an adhesive resin, an acid-modified polyolefin having an acidic group, The adhesive resin has a Vicat softening temperature of 90° C. or higher; The outer layer comprises one or more selected from the group consisting of polyethylene, polypropylene, and polyamide, The intermediate layer contains biomass-derived polyethylene as the polyethylene, in the inner layer, a ratio of a total content of the linear low density polyethylene and the metallocene-catalyzed linear low density polyethylene to a content of the polyethylene is 80 to 100 mass%, In the functional layer, a ratio of a total content of the polyamide and the ethylene-vinyl alcohol copolymer to a total mass of the functional layer is 90 to 100 mass%, In the adhesive layer, the ratio of the content of the modified polyolefin to the content of the adhesive resin is 80 to 100 mass %, In the outer layer, a ratio of a total content of the polyethylene, the polypropylene, and the polyamide to a total mass of the outer layer is 90 to 100 mass%, In the intermediate layer, a ratio of a content of the biomass-derived polyethylene to a content of the polyethylene is 50 to 100 mass%; The laminated film includes, as the functional layer, a functional layer (a) and no functional layer (b), or includes the functional layer (a) and a functional layer (b) provided in direct contact with one surface of the functional layer (a), the functional layer (a) containing the polyamide and the functional layer (b) containing the ethylene-vinyl alcohol copolymer, and when the laminated film includes the functional layer (a) and the functional layer (b), the laminated film includes the functional layer (b) and the functional layer (a) in this order in the direction from the inner layer to the adhesive layer, When the thickness of the inner layer is 45 μm or less, the Vicat softening temperature of the adhesive resin is 105 to 115° C., when the thickness of the inner layer is 40 to 75 μm, the Vicat softening temperature of the adhesive resin is either 95 to 115° C. or 100 to 115° C., and when the thickness of the inner layer is 70 μm or more, the Vicat softening temperature of the adhesive resin is either 90 to 115° C., 95 to 115° C., or 100 to 115° C.

[0172] <<Laminated film manufacturing method>> The laminated film can be produced, for example, by a feed block method in which resins or resin compositions that are materials for forming each layer are melt-extruded using several extruders, a co-extrusion T-die method such as a multi-manifold method, or an air-cooled or water-cooled co-extrusion inflation method.

[0173] When the resin composition is used, for example, a mixture of two or more components (dry blend, non-kneaded material) may be directly fed into the extruder as the resin composition, or a pre-kneaded material in which two or more components are kneaded in advance may be fed into the extruder as the resin composition. The pre-kneaded product can be obtained, for example, by melt-kneading two or more components using an apparatus such as a twin-screw extruder or a Banbury mixer.

[0174] The laminate film can also be produced by coating a resin or resin composition, etc., which is a material for forming one of the layers, on the surface of another layer that constitutes the laminate film, and drying it as necessary to form a laminate structure in the laminate film, and if necessary, further laminating other layers so as to obtain the desired arrangement.

[0175] The laminated film can also be produced by separately preparing two or more films for constituting any two or more of the layers, laminating the films together using an adhesive by any one of dry lamination, extrusion lamination, hot melt lamination and wet lamination, and further laminating other layers as necessary so as to form the desired arrangement. In this case, the adhesive used may be one capable of forming the adhesive layer.

[0176] The laminated film can also be produced by laminating two or more films, which have been prepared separately in advance, by a thermal lamination method or the like without using an adhesive, and, if necessary, further laminating other layers so as to achieve the desired arrangement.

[0177] When producing the laminated film, two or more of the methods for forming any of the layers (in other words, films) in the laminated film mentioned above may be combined.

[0178] Regardless of the manufacturing method, the resin composition that is the material for forming any layer in the laminated film may be manufactured by adjusting the type and content of the components so that the layer to be formed contains the desired components in the desired content. For example, the content ratio of the components that do not vaporize at room temperature in the resin composition is usually the same as the content ratio of the components in the layer formed from this resin composition.

[0179] An example of a resin composition (sometimes referred to herein as an "inner layer forming composition") for forming an inner layer (for example, inner layer 11 in the laminate film 1 shown in FIG. 1) is a resin composition containing polyethylene and, if necessary, the other components described above.

[0180] Examples of resin compositions (sometimes referred to in this specification as "adhesive layer-forming compositions") for forming adhesive layers (e.g., adhesive layer 13 in the laminate film 1 shown in Figure 1) and outer adhesive layers (e.g., outer adhesive layer 16 in the laminate film 1 shown in Figure 1) include resin compositions containing an adhesive resin and, if necessary, the other components described above.

[0181] Examples of resin compositions (sometimes referred to in this specification as "compositions for forming functional layers") for forming functional layers (e.g., functional layer 12 in the laminate film 1 shown in Figure 1) include resin compositions containing either or both of polyamide and ethylene-vinyl alcohol copolymer, and, if necessary, the other components described above.

[0182] Examples of the resin composition (sometimes referred to in this specification as an "outer layer forming composition") for forming an outer layer (for example, outer layer 14 in the laminate film 1 shown in FIG. 1) include a resin composition containing one or more types selected from the group consisting of polyethylene, polypropylene, and polyamide, and, if necessary, the other components described above.

[0183] Examples of resin compositions (sometimes referred to in this specification as "compositions for forming intermediate layers") for forming the intermediate layer (e.g., intermediate layer 15 in the laminate film 1 shown in Figure 1), the first intermediate layer (e.g., first intermediate layer 151 in the laminate film 2 shown in Figure 2), and the second intermediate layer (e.g., second intermediate layer 152 in the laminate film 2 shown in Figure 2) include resin compositions containing polyethylene and, if necessary, the other components described above.

[0184] <<Packaging>> A packaging body according to one embodiment of the present invention is constructed using the laminate film according to one embodiment of the present invention described above. The packaging body of this embodiment is constructed using the laminated film, even if it is a packaging body containing a liquid food, and therefore when the packaging body is heat-treated, tearing of the packaging body is suppressed at the heat-sealed portion, particularly at the above-mentioned protruding heat-sealed portion. This is also true when the packaging body is heat-treated (boiled) with hot water. Furthermore, when the packaging body is heat-treated with hot water in a closed space, as explained above, the temperature in the space is likely to rise excessively, and the pressure in the storage portion of the packaging body is also likely to rise excessively, making the packaging body even more likely to tear, but even under such harsh conditions, tearing of the packaging body is suppressed.

[0185] Since the packaging body of this embodiment has the above-mentioned characteristics, it is useful for food containing liquid, such as boiled fish, and is particularly useful as a vacuum packaging body for packaging food containing liquid.

[0186] The packaging body of the present embodiment may include a molded product (for example, a heat-molded product) of the laminated film, or may include the laminated film as is without being molded.

[0187] The packaging body of the present embodiment may be a known packaging body, except for the use of the laminated film.

[0188] A preferred package of the present embodiment is, for example, a package that includes a lid material and a base material, is formed by sealing the lid material and the base material, and the base material is formed using the laminate film.

[0189] FIG. 5 is a cross-sectional view illustrating an example of the packaging body of the present embodiment. The packaging body 101 shown in Fig. 5 is configured to include a lid material 8 and a base material 10. The base material 10 is configured using the laminated film 1 shown in Fig. 1, and more specifically, is a molded body (heat-molded body) of the laminated film 1. In the base material 10 in FIG. 5, the distinction between the layers in the laminate film 1 constituting it is omitted.

[0190] The base material 10 has a recess 100 formed therein. One side (sometimes referred to as the "second side" in this specification) 10b of the base material 10 and one side (sometimes referred to as the "second side" in this specification) 8b of the cover material 8 are both sealing surfaces, and they face each other in the packaging body 101. In the package 101, the second surface 10b of the base material 10, excluding the area where the recess 100 is formed, and the second surface 8b of the lid material 8, near the peripheral edge, are overlapped. At least the areas near the peripheral edges of the overlapped areas of the base material 10 and the lid material 8 are heat-sealed to form the package 101. As a result, in the area of ​​the recess 100 of the base material 10, a storage section 101a is formed between the second surface 10b of the base material 10 and the second surface 8b of the lid material 8. An item 9 is stored in the storage section 101a.

[0191] The stored item 9 is the above-mentioned packaged item, and is preferably a food product containing a liquid. In FIG. 5, the liquid present inside the storage section 101a is omitted.

[0192] In the packaging body 101, at least a part of the heat-sealed area between the base material 10 and the lid material 8 is protruding from the lid material 8 side toward the base material 10 side (for example, from the inner layer 11 side toward the functional layer 12 side of the base material 10) (not shown). In such a protruding heat-sealed area, the inclusion of liquid material originating from the stored item 9 (which is part of the stored item 9) is suppressed. Even though the packaging body 101 has such a protruding heat-sealed area, because the laminate film 1 is used, tearing of the packaging body is suppressed even when the packaging body is heat-treated as described above.

[0193] The base material 10 is a molded body (heat-molded body) of the laminated film 1, and the second surface 10b of the base material 10 is preferably the same as the second surface 11b of the inner layer 11 in the laminated film 1. The other surface 10a of the base material 10 (sometimes referred to as the "first surface" in this specification) is preferably the same as the first surface 14a of the outer layer 14 in the laminated film 1.

[0194] The lid material 8 may be the laminate film, or may be a resin film other than the laminate film.

[0195] When the lid material 8 is the laminate film, the lid material 8 may be the laminate film 1 shown in FIG. 1, or may be any other laminate film. When the lid material 8 is the laminate film, the second surface 8b of the lid material 8 is preferably the same as the surface of the inner layer in the laminate film opposite to the functional layer side (for example, in the case of the laminate film 1 shown in FIG. 1, the second surface 11b of the inner layer 11). The other surface (sometimes referred to as the "first surface" in this specification) 8a of the lid material 8 is preferably the same as the surface of the outer layer in the laminate film opposite to the functional layer side (for example, in the case of the laminate film 1 shown in FIG. 1, the first surface 14a of the outer layer 14).

[0196] When the cover material 8 is a resin film other than the laminated film, the resin film may be a known film. The resin film constituting the lid member 8 may be made of one layer (single layer), or may be made of two or more layers.

[0197] The resin film consisting of multiple layers may be, for example, a laminated film for lids, which is constructed by laminating an inner layer (sometimes referred to as "inner layer for lids" in this specification) containing polyethylene (PE) and an outer layer (sometimes referred to as "outer layer for lids" in this specification) containing polyamide (PA). The inner layer for lids functions as a sealant layer. The outer layer for lids is preferably a biaxially stretched layer.

[0198] In this specification, unless otherwise specified, the mere term "inner layer" refers to the inner layer in the laminate film according to one embodiment of the present invention described above. Similarly, the mere term "outer layer" refers to the outer layer in the laminate film according to one embodiment of the present invention described above, unless otherwise specified. Similarly, the mere term "laminate film" refers to the laminate film according to one embodiment of the present invention described above, unless otherwise specified.

[0199] The polyethylene contained in the inner layer for the covering material may be, for example, the same as the polyethylene contained in the inner layer in the laminate film. The polyamide contained in the outer layer for covering material may be, for example, the same polyamide as that contained in the functional layer in the laminated film.

[0200] The other resin films constituting the lid material 8 can be manufactured in the same manner as the laminated film, except that the number of layers that need to be formed and either or both of the type of resin or the composition of the resin composition used to form any of the layers are different.

[0201] The thickness of the base material 10 at its flat portion may be similar to the thickness of the laminated film described above. The thickness of the lid material 8 is preferably 50 to 100 μm.

[0202] In Figure 5, some gaps can be seen between the stored item 9 and the base material 10, and between the stored item 9 and the lid material 8 within the storage section 101a of the packaging body 101. However, the presence of these gaps is not essential for the packaging body 101 in which the stored item 9 is stored.

[0203] The packaging body of this embodiment is not limited to the packaging body 101 shown in FIG. 5, and for example, some of the configuration of the packaging body 101 may be changed, deleted, or added without departing from the spirit of the present invention. For example, in the packaging body 101, the base material 10 is configured using the laminate film 1 shown in FIG. 1, but may be configured using a laminate film other than the laminate film 1 of this embodiment. For example, in the packaging body 101, the base material 10 is made of the laminate film 1 shown in Fig. 1, but may be made of a resin film other than the laminate film of this embodiment. In that case, however, the lid material 8 is the laminate film of this embodiment.

[0204] <<Manufacturing method of packaging body>> The packaging body can be produced by packaging an object to be packaged (in other words, an object to be stored) with the laminate film. The packaging body can be produced in the same manner as the conventional packaging body, except that the laminate film is used instead of the conventional resin film. When producing a package, the inner layer of the laminate film or its molded body is placed facing the object to be packaged, and the functional layer (or the outer layer if the laminate film has an outer layer) is placed facing away from the object to be packaged, and the object is packaged.

[0205] More specifically, the package of this embodiment can be manufactured by, for example, forming a storage section for storing the packaged object (in other words, the stored object) using the laminate film or its molded body, the laminate film, another resin film other than the laminate film, or a molded body of any of these films, storing the packaged object, and heat-sealing the area other than the storage section of these films or molded bodies. At this time, the sealing pressure during heat sealing is increased from the inner layer side of the laminate film or its molded body toward the functional layer side, more than usual, so that the shape of the heat-sealed area is made to protrude toward the functional layer side. In this way, the inclusion of liquid in the sealed area is suppressed.

[0206] In the case of a vacuum package, for example, a package can be manufactured by forming a storage section for storing the packaged object with a base material (e.g., a molded body of the laminated film) and a lid material (the laminated film or another resin film) and storing the packaged object while depressurizing the inside of the storage section and heat-sealing the areas of the base material and lid material other than the storage section. At this time, the sealing pressure during heat sealing is increased from the inner layer side to the functional layer side of the molded body of the laminated film more than usual, so that the shape of the heat-sealed area is made to protrude toward the functional layer side. In this way, the inclusion of liquid in the sealed area is suppressed.

[0207] When the laminated film is heat molded, the molding temperature is preferably 85 to 105° C., and the heating time is preferably 1 to 2 seconds.

[0208] Not only in the case of vacuum packages, but in the production of packages, the heating temperature during heat sealing is preferably 135 to 140° C., and the sealing pressure is preferably 0.1 to 0.3 MPa.

[0209] <<How to use the packaging>> The package can be appropriately heat-treated, for example, for the purpose of heat sterilization of the contents (packaged items) or for warming the contents (packaged items) before consumption by the consumer. The temperature for the heat treatment of the package can be, for example, 85 to 100° C., and can also be an extremely high temperature such as 95 to 100° C. If the heating temperature is 100° C. or less, breakage of the package can be suppressed. EXAMPLES

[0210] The present invention will be described in more detail below with reference to specific examples, although the present invention is not limited to the following examples.

[0211] The resins used in each of the examples and comparative examples are as follows. mLLDPE: Metallocene-catalyzed linear low-density polyethylene (Ube Maruzen Polyethylene Co., Ltd. "Yumerit (registered trademark) 4040F"), density 0.937 g / cm 3 , MFR4g / 10min, melting point 126℃, Vicat softening temperature 119℃) LDPE: Biomass-derived low-density polyethylene (Braskem "SEB853", density 0.923 g / cm 3 , MFR2.7g / 10min, melting point 110℃, Vicat softening temperature 95℃) PA: 6-Nylon (UBE "Nylon 1024") Modified PE (1): Acid-modified polyethylene (adhesive resin, Mitsui Chemicals "Admer (registered trademark) NF308", density 0.932 g / cm 3 , MFR 1.7g / 10min, Vicat softening temperature 113℃, melting point 125℃) Modified PE (2): Acid-modified polyethylene (adhesive resin, Mitsui Chemicals "Admer (registered trademark) NF539", density 0.905 g / cm 3 , MFR3.5g / 10min, Vicat softening temperature 68℃, melting point 120℃) Modified PE (3): Acid-modified polyethylene (adhesive resin, Mitsui Chemicals "Admer (registered trademark) NB508", density 0.915 g / cm 3 , MFR 1.4g / 10min, Vicat softening temperature 93℃, melting point 120℃) Modified PE (4): Acid-modified polyethylene (adhesive resin, Mitsui Chemicals "Admer (registered trademark) NF518", density 0.911 g / cm 3 , MFR2.4g / 10min, Vicat softening temperature 85℃, melting point 120℃)

[0212] [Example 1] <<Laminated film manufacturing>> By co-extruding the mLLDPE, the modified PE (1), the PA, the modified PE (2), the LDPE, and the mLLDPE in this order, a laminated film (thickness 100 μm) having the configuration shown in FIG. 1 was obtained, in which an inner layer (thickness 30 μm), an adhesive layer (thickness 7 μm), a functional layer (thickness 20 μm), an outer adhesive layer (thickness 7 μm), a second intermediate layer (thickness 14 μm), and an outer layer (thickness 22 μm) were laminated in this order in the thickness direction. The inner layer, adhesive layer, functional layer, outer adhesive layer, second intermediate layer, and outer layer are all unstretched layers and are transparent.

[0213] <<Packaging Manufacturing>> The laminated film obtained above was cut into a width of 422 mm, which was used as a laminated film for the base material of deep-draw vacuum packaging.

[0214] A biaxially oriented nylon film (Toyobo Co., Ltd. "N1102", thickness 15 μm) and an LLDPE film (Futamura Chemical Co., Ltd. "LL-XMTN", thickness 50 μm) were dry laminated to produce a lid material laminate film (thickness 65 μm). This lid material laminate film was cut into a width of 422 mm and used as a lid material for deep-draw vacuum packaging.

[0215] <<Packaging Manufacturing>> A deep-drawing vacuum packaging machine, MULTIVAC's "R535," was used to deep-draw the laminated film for the base material at a forming temperature of 95°C and a heating time of 1.5 seconds to produce a base material with a drawing depth of 15 mm. Furthermore, the storage section in the base material was filled with boiled fish and broth, and the base material and lid material were heat-sealed under conditions of a sealing temperature of 140°C, a sealing time of 1.5 seconds, and a sealing pressure of 0.2 MPa, with the pressure inside the storage section (degree of reduction in pressure) set to 2.5 kPa (25 mbar), to produce a package (deep-drawn package).

[0216] <<Package evaluation>> <Evaluation of the effect of preventing package breakage during heat treatment> The pot with water and lid was placed on the fire and the water was boiled. The lid was then opened and the 10 packages obtained above were placed in the boiling water (hot water), the pot was covered again, and the pot was placed on the fire as it was, whereby the packages were heat-treated for 30 minutes. After the heat treatment, the packages were removed from the pot and visually observed to confirm the number of packages that had been broken (number of broken packages). The results are shown in Table 1.

[0217] <<Laminated film manufacturing, and packaging manufacturing and evaluation>> [Example 2] Except for using the modified PE (3) instead of the modified PE (1) and changing the conditions for co-extrusion of the resins, the same method as in Example 1 was used to obtain a laminated film (thickness 200 μm) having the configuration shown in FIG. 1, in which an inner layer (thickness 80 μm), an adhesive layer (thickness 14 μm), a functional layer (thickness 40 μm), an outer adhesive layer (thickness 14 μm), a second intermediate layer (thickness 18 μm), and an outer layer (thickness 34 μm) were laminated in this order in the thickness direction. The inner layer, adhesive layer, functional layer, outer adhesive layer, second intermediate layer, and outer layer are all unstretched layers and are transparent. Except for using the laminated film obtained here, a comparative package was produced and evaluated in the same manner as in Example 1. The results are shown in Table 1.

[0218] [Example 3] By co-extruding the mLLDPE, the LDPE, the modified PE (1), the PA, the modified PE (2), and the mLLDPE in this order, a laminated film (thickness 200 μm) having the configuration shown in FIG. 3 was obtained, in which an inner layer (thickness 80 μm), a first intermediate layer (thickness 18 μm), an adhesive layer (thickness 14 μm), a functional layer (thickness 40 μm), an outer adhesive layer (thickness 14 μm), and an outer layer (thickness 34 μm) were laminated in this order in the thickness direction. The inner layer, the first intermediate layer, the adhesive layer, the functional layer, the outer adhesive layer, and the outer layer are all unstretched layers and are transparent. Except for using the laminated film obtained here, a comparative package was produced and evaluated in the same manner as in Example 1. The results are shown in Table 1.

[0219] [Comparative Example 1] By co-extruding the mLLDPE, the modified PE (2), the PA, the modified PE (2), the LDPE, and the mLLDPE in this order, a comparative laminated film (thickness 100 μm) having a configuration similar to that shown in FIG. 1, in which an inner layer (thickness 30 μm), an adhesive layer (thickness 7 μm), a functional layer (thickness 20 μm), an outer adhesive layer (thickness 7 μm), a second intermediate layer (thickness 14 μm), and an outer layer (thickness 22 μm) are laminated in this order in the thickness direction. The inner layer, adhesive layer, functional layer, outer adhesive layer, second intermediate layer, and outer layer are all unstretched layers and are transparent. Except for using the laminated film obtained here, a comparative package was produced and evaluated in the same manner as in Example 1. The results are shown in Table 1.

[0220] [Comparative Example 2] Except for using the modified PE (4) instead of the modified PE (1), the same method as in Example 1 was used to obtain a comparative laminated film (thickness 100 μm) having a configuration similar to that shown in FIG. 1, in which an inner layer (thickness 30 μm), an adhesive layer (thickness 7 μm), a functional layer (thickness 20 μm), an outer adhesive layer (thickness 7 μm), a second intermediate layer (thickness 14 μm), and an outer layer (thickness 22 μm) were laminated in this order in the thickness direction. The inner layer, adhesive layer, functional layer, outer adhesive layer, second intermediate layer, and outer layer are all unstretched layers and are transparent. Except for using the laminated film obtained here, a comparative package was produced and evaluated in the same manner as in Example 1. The results are shown in Table 1.

[0221] [Table 1]

[0222] As is clear from the above results, in Examples 1 to 3, the effect of suppressing breakage of the package when the package was heat-treated was high. In Examples 1 to 3, the Vicat softening temperature of the adhesive resin contained in the adhesive layer in the laminated film was 93° C. or higher (93 to 113° C.).

[0223] In contrast, in Comparative Examples 1 and 2, the effect of preventing the packages from breaking when the packages were heat-treated was low. In Comparative Examples 1 and 2, the Vicat softening temperature of the adhesive resin contained in the adhesive layer in the laminated film was 85° C. or lower (68 to 85° C.). [Industrial Applicability]

[0224] INDUSTRIAL APPLICABILITY The present invention can be used for a package for packaging food containing a liquid and subjecting the food to a heat treatment after packaging. [Explanation of symbols]

[0225] 1,2,3,4...Laminated film 11...Inner layer 12: functional layer; 12a: surface of the functional layer opposite to the adhesive layer side 13...adhesive layer 14...outer layer 15...intermediate layer, 151...first intermediate layer, 152...second intermediate layer 8...Lid material 10...Bottom material 101...Packaging

Claims

1. A laminated film for producing a package in which a food product containing a liquid is packaged and for heat-treating the package, comprising: The laminated film includes an inner layer, an adhesive layer, and a functional layer, and the inner layer and the functional layer are bonded to each other by the adhesive layer. the inner layer comprises polyethylene; the functional layer comprises either one or both of a polyamide and an ethylene-vinyl alcohol copolymer, the adhesive layer comprises an adhesive resin, A laminated film, wherein the adhesive resin has a Vicat softening temperature of 90°C or higher.

2. 2. The laminated film according to claim 1, wherein the adhesive resin has a melt flow rate of 3 g / 10 min or less.

3. The adhesive resin has a density of 0.91 g / cm ３ The laminate film according to claim 1 or 2.

4. The laminated film according to claim 1 or 2, wherein the adhesive resin is an acid-modified polyethylene.

5. 3. The laminated film according to claim 1, wherein the inner layer has a thickness of 10 to 100 μm.

6. 3. The laminated film according to claim 1, wherein the polyethylene contained in the inner layer has a Vicat softening temperature of 90°C or higher.

7. The laminated film further includes an outer layer provided on a surface of the functional layer opposite to the adhesive layer, The laminate film according to claim 1 , wherein the outer layer comprises one or more materials selected from the group consisting of polyethylene, polypropylene, and polyamide.

8. The laminated film further includes an intermediate layer provided between the outer layer and the functional layer, 8. The laminate film of claim 7, wherein the intermediate layer comprises polyethylene.

9. The laminated film according to claim 8, wherein the polyethylene has a Vicat softening temperature of 90°C or higher.

10. The laminated film according to claim 8 or 9, wherein the polyethylene is a biomass-derived polyethylene.

11. The laminated film according to claim 8 or 9, wherein the outer layer comprises the polyethylene having a Vicat softening temperature of 90°C or higher.

12. A packaging material formed using the laminate film according to claim 1 or 2.

13. The packaging body comprises a lid material and a base material, The packaging body is formed by sealing the lid material and the base material, The packaging body according to claim 12, wherein the base material is formed using the laminated film.

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