Laminated films and packaging

Abstract

To provide a resin film capable of manufacturing packaging, wherein a long base material is manufactured using the resin film, the base material and the long lid material are heat-sealed to create a long sealed body in which storage compartments are continuously provided in the longitudinal direction, and the sealed body is cut into individual storage compartments, thereby ensuring good cutability of the sealed body even when the resin film is thin, and to provide a packaging body constructed using the resin film. [Solution] A laminated film 1 comprising an easy-peel layer 11, a buffer layer 12 adjacent to the easy-peel layer 11, and an outer layer 13, wherein the buffer layer 12 contains an ionomer, the outer layer 13 contains an amorphous polyester, and when the storage modulus E'(90) at 90°C and the storage modulus E'(140) at 140°C are measured by dynamic viscoelasticity measurement of the laminated film 1, the ratio E'(90) / E'(140) is 6 or more. A packaging body constructed using the laminated film 1.

Description

[Technical Field]

[0001] This invention relates to laminated films and packaging materials. [Background technology]

[0002] Various food products, including processed meat products, are packaged using, for example, a bottom and bottom material made of resin film. The packaged product (food) is sandwiched between the bottom and bottom materials, and the bottom and bottom materials are heat-sealed. The bottom material used is one that has a recess to form a compartment for storing the packaged product.

[0003] Currently, so-called "continuous packs" are widely available on the market, in which multiple packages containing processed meat products such as ham and bacon are attached to each other with adhesive seals in recesses in the base material (see Patent Document 1). For these continuous packs, there is a demand for base materials that are thin.

[0004] During the manufacturing of packaging, long base and lid materials are typically produced. These base and lid materials are then heat-sealed along their longitudinal direction to create a long sealed body with storage compartments arranged continuously along its longitudinal direction. Finally, this sealed body is cut along its longitudinal direction to produce individual storage compartments, thereby manufacturing the packaging. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2007-98579 [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] However, conventionally, the bottom material for such multi-pack packaging has mainly been around 80-120 μm thick. When a thin resin film less than 60 μm thick is used to manufacture the bottom material, and then this bottom material is used to manufacture the packaging, the cutting performance deteriorates when cutting the seal, resulting in the problem that the packaging cannot be manufactured properly.

[0007] The present invention aims to provide a resin film capable of manufacturing packaging bodies, wherein a long base material is manufactured using the resin film, and a long lid material is heat-sealed to produce a long sealed body in which storage compartments are continuously provided in the longitudinal direction, and the sealed body is cut along its longitudinal direction for each storage compartment, thereby providing a resin film in which the seal body has good cutability even when the resin film is thin, and a packaging body constructed using the resin film. [Means for solving the problem]

[0008] To solve the above problems, the present invention adopts the following configuration. [1] A laminated film comprising an easy-peel layer, a buffer layer adjacent to the easy-peel layer, and an outer layer, wherein the buffer layer contains an ionomer, the outer layer contains an amorphous polyester, and when the storage modulus E'(90) at 90°C and the storage modulus E'(140) at 140°C are measured by dynamic viscoelasticity measurement of the laminated film, the ratio E'(90) / E'(140) is 6 or greater when the vibration frequency is 1 Hz. [2] The laminated film according to [1], wherein the thickness of the laminated film is 60 μm or less. [3] The laminated film according to [1] or [2], wherein the melt flow rate of the ionomer, as measured in accordance with JIS K 7210:1999, is 0.5 to 5 g / 10 min. [4] The laminated film according to any one of [1] to [3], wherein the easy-peel layer comprises an ethylene polymer and a propylene polymer. [5] The laminated film according to any one of [1] to [4], further comprising a pinhole-resistant layer containing polyamide. [6] The laminated film according to any one of [1] to [5], further comprising an oxygen barrier layer containing an ethylene-vinyl alcohol copolymer.

[0009] [7] A package formed using the laminated film according to any one of [1] to [6]. [8] The package according to [7], comprising a lid material and a bottom material, the package being formed by sealing the lid material and the bottom material, and the bottom material being a molded body of the laminated film. [Advantages of the Invention]

[0010] According to the present invention, there is provided a resin film capable of manufacturing a package. By manufacturing a long bottom material using the resin film and heat-sealing this bottom material and a long lid material, a long sealed body in which storage portions are continuously provided in the longitudinal direction is produced. When manufacturing the package by cutting this sealed body at each storage portion in its longitudinal direction, even if the thickness of the resin film is thin, a resin film with good cutability of the sealed body and a package formed using the resin film are provided. [Brief Description of the Drawings]

[0011] [Figure 1] It is a cross-sectional view schematically showing an example of a laminated film according to an embodiment of the present invention. [Figure 2] It is a cross-sectional view schematically showing an example of a package according to an embodiment of the present invention. [Modes for Carrying Out the Invention]

[0012] [[Laminated Film]] A laminated film according to an embodiment of the present invention is a laminated film including an easy-peel layer, a buffer layer adjacent to the easy-peel layer, and an outer layer, The buffer layer contains an ionomer, The outer layer contains amorphous polyester, Dynamic Mechanical Analysis (DMA) of the laminated film is used to measure the storage modulus E'(90) at 90°C (sometimes simply referred to as "E'(90)" in this specification) and the storage modulus E'(140) at 140°C (sometimes simply referred to as "E'(140)" in this specification) when the vibration frequency is 1 Hz. The ratio E'(90) / E'(140) is 6 or greater.

[0013] When attempting to manufacture packaging by producing a long base material using a conventional thin resin film, then heat-sealing this base material and a long lid material to create a long sealed body with storage compartments continuously arranged along its length, and then cutting this sealed body along its length to create each storage compartment, it is difficult to cut properly, resulting in poor cutability. This is presumed to be because the heat generated during heat sealing causes the thin base material to remain at a high temperature and soften even when the sealed body is cut. In contrast, when a packaging body is manufactured in the same manner using the laminated film of this embodiment, even if the thickness of the laminated film is thin, the fact that E'(90) / E'(140) is 6 or more results in good cutability of the sealing body. In this embodiment, the buffer layer in the laminated film contains an ionomer, which facilitates the adjustment of E'(90) / E'(140).

[0014] On the other hand, when a long piece of resin film is wound into a roll immediately after manufacturing, tension is applied in the winding direction. Furthermore, resin film manufactured under high-temperature conditions using methods such as the melt extrusion method described later usually remains at a high temperature immediately after manufacturing. Consequently, due to the effect of this tension, the width of the resin film tends to be narrower just before winding than it was immediately after manufacturing, and this phenomenon is called neck-in. Moreover, if the winding speed of the resin film is increased to increase the production volume of resin film, this neck-in becomes even more pronounced. In other words, a long piece of resin film immediately after manufacturing usually tends to narrow in width as it moves away from the manufacturing equipment such as the extruder (in other words, as it approaches the winding roll). In contrast, in the laminated film of this embodiment, the presence of an ionomer in the buffer layer suppresses such neck-in.

[0015] On the other hand, when a package is manufactured by producing a long sealing body using a long base material and a long lid material, which are molded bodies of thin resin film, and cutting this sealing body, the non-storage portion of the resulting package tends to develop a curl where the side of the base material becomes concave in the TD (direction perpendicular to the resin flow direction) of the package. Here, the non-storage portion refers to the part of the package other than the storage portion formed by the concave portion of the base material, and includes the sealing portion. In contrast, by using the base material, which is a molded laminated film of this embodiment, curling is suppressed in the packaging even if the thickness of the laminated film is thin. This is presumed to be because the buffer layer contains an ionomer. Since multiple packaging bodies in which curling is suppressed can be easily bonded together with adhesive seals, they are particularly suitable for forming a series of packs.

[0016] The laminated film of this embodiment is suitable for food packaging, and more suitable for packaging processed meat products such as ham and bacon. Among these, the thin laminated film is particularly suitable for packaging that forms a series of multiple packages containing these foods. Furthermore, the laminated film of this embodiment is suitable for forming a base material with recesses that serve as storage compartments for these packages, and is more suitable for forming a base material with shallow recesses.

[0017] The present invention will be described in detail below with reference to the drawings. Note that, for convenience in making the features of the present invention easier to understand, the drawings may show enlarged versions of key parts, and the dimensional ratios of each component may not be the same as those in reality.

[0018] Figure 1 is a schematic cross-sectional view showing an example of a laminated film according to this embodiment. The laminated film 1 shown here comprises an easy-peel layer 11, a buffer layer 12 adjacent to the easy-peel layer 11, and an outer layer 13. In the laminated film 1, the easy-peel layer 11 is the outermost layer of one side, and the outer layer 13 is the outermost layer of the other side. In the laminated film of this embodiment, the outermost layer refers to the outermost layer in the stacking direction of each layer constituting the laminated film, and the outermost surface, as described later, refers to the outermost surface (i.e., exposed surface) in the stacking direction of each layer constituting the laminated film.

[0019] The buffer layer 12 contains an ionomer. The outer layer 13 contains amorphous polyester. In laminated film 1, E'(90) / E'(140) is 6 or greater.

[0020] The laminated film 1 further includes a pinhole-resistant layer 14 and an oxygen barrier layer 15 between the buffer layer 12 and the outer layer 13, in that order, from the buffer layer 12 side toward the outer layer 13 side. The laminated film 1 further includes an adhesive layer 16 between the buffer layer 12 and the pinhole-resistant layer 14, and an adhesive layer 16 between the oxygen barrier layer 15 and the outer layer 13. In this embodiment, the adhesive layer between the buffer layer and the pinhole-resistant layer may be referred to as the "first adhesive layer," and the adhesive layer between the oxygen barrier layer and the outer layer may be referred to as the "second adhesive layer." The laminated film 1 includes the first adhesive layer 161 and the second adhesive layer 162. The first adhesive layer 161 and the second adhesive layer 162 may be the same as or different from each other.

[0021] In other words, the laminated film 1 is constructed by laminating the easy-peel layer 11, the buffer layer 12, the first adhesive layer 161, the pinhole-resistant layer 14, the oxygen barrier layer 15, the second adhesive layer 162, and the outer layer 13 in this order in the thickness direction.

[0022] One side 11b of the easy-peel layer 11 (the side opposite to the outer layer 13, sometimes referred to as the "second side" in this specification) is one of the outermost surfaces 1b of the laminated film 1 (sometimes referred to as the "second side" in this specification), and is the exposed surface.

[0023] One surface 13a of the outer layer 13 (the surface opposite to the side of the easy-peel layer 11, sometimes referred to as the "first surface" in this specification) is the other outermost surface 1a of the laminated film 1 (sometimes referred to as the "first surface" in this specification), and is the exposed surface.

[0024] A packaging body can be constructed by heat-sealing laminated films 1 together at the easy-peel layer 11 within them, or by heat-sealing laminated films 1 together with other films or sheets at the easy-peel layer 11 within them. The second surface 11b of the easy-peel layer 11 serves as the sealing surface between easy-peel layers 11 and other films or sheets.

[0025] The laminated film of this embodiment is not limited to laminated film 1, and some components of laminated film 1 may be modified, deleted, or added without departing from the spirit of the present invention. For example, the laminated film 1 shown in Figure 1 has a pinhole-resistant layer 14 and an oxygen barrier layer 15 arranged in this order from the easy-peel layer 11 side toward the outer layer 13 side. However, the laminated film of this embodiment may have an oxygen barrier layer and a pinhole-resistant layer arranged in this order from the easy-peel layer side toward the outer layer side. The laminated film of this embodiment only needs to include at least an easy-peel layer, a buffer layer, and an outer layer, and does not need to include any other layers. In other words, the pinhole-resistant layer, oxygen barrier layer, and adhesive layer are arbitrary layers. However, in terms of improving the properties of the laminated film, it is preferable that the laminated film of this embodiment includes either or both of the pinhole-resistant layer and the oxygen barrier layer. The laminated film of this embodiment may, if necessary, include other layers that do not fall under any of the following categories: easy-peel layer, buffer layer, pinhole-resistant layer, oxygen barrier layer, outer layer, or adhesive layer, as long as they do not impair the effects of the present invention.

[0026] The laminated film of this embodiment will be described in more detail below.

[0027] <E’(90) / E’(140)> The E'(90) / E'(140) of the laminated film is 6 or greater, preferably 6.5 or greater, more preferably 7 or greater, and even more preferably 7.5 or greater. For example, it may be 8 or greater and 8.5 or greater. The larger the E'(90) / E'(140), the more likely the cutting performance of the sealing body is to improve. The upper limit of E'(90) / E'(140) is not particularly limited. For example, laminated films in which E'(90) / E'(140) is 10 or less can be more easily realized. In one embodiment, E'(90) / E'(140) may be any of 6-10, 6.5-10, 7-10, 7.5-10, 8-10, and 8.5-10. However, these are just examples of E'(90) / E'(140).

[0028] In this embodiment, it is preferable that E'(90) / E'(140) satisfies the above-mentioned numerical range when the direction of the stress applied to the laminated film during the measurement of E'(90) and E'(140) is aligned with the MD (Machine Direction, resin flow direction) of the laminated film. That is, it is preferable that the above-mentioned numerical range of E'(90) / E'(140) is the numerical range of E'(90) / E'(140) in the MD of the laminated film.

[0029] In this embodiment, it is preferable that when the direction of the stress applied to the laminated film during the measurement of E'(90) and E'(140) is aligned with the TD (Transverse Direction, the direction perpendicular to the resin flow direction (MD)) of the laminated film, E'(90) / E'(140) satisfies the above-mentioned numerical range. That is, it is preferable that the above-mentioned numerical range of E'(90) / E'(140) is the numerical range of E'(90) / E'(140) at the TD of the laminated film.

[0030] In this embodiment, it is preferable that both E'(90) / E'(140) in the MD of the laminated film and E'(90) / E'(140) in the TD of the laminated film satisfy the numerical range of E'(90) / E'(140) described above.

[0031] In this embodiment, when a seal body is made by heat-sealing a base material obtained using a laminated film with a lid material, the heat-sealing temperature of the base material is assumed to be, for example, 140°C or a temperature close to that. On the other hand, in this embodiment, when manufacturing the packaging by cutting the sealing body, it is assumed that the cutting temperature of the sealing body is, for example, 90°C or a temperature close to that. That is, E’(90) / E’(140) is set in consideration of these heat sealing temperature and cutting temperature. In this embodiment, E’(90) does not become relatively too small compared to E’(140), and a laminated film having appropriate hardness even at 90°C is specified. Such a laminated film improves the cutability of the seal body at a temperature of 90°C or in the vicinity thereof.

[0032] <E’(90)> The E’(90) of the laminated film is not particularly limited as long as E’(90) / E’(140) is 6 or more, but it is preferably 2×10 8 ~3×10 8 Pa. In this embodiment, when the direction of the stress applied to the laminated film during the measurement of E’(90) is made to coincide with the MD of the laminated film, E’(90) (that is, E’(90) in the MD of the laminated film) is preferably 2×10 8 ~3×10 8 Pa. In this embodiment, when the direction of the stress applied to the laminated film during the measurement of E’(90) is made to coincide with the TD of the laminated film, E’(90) (that is, E’(90) in the TD of the laminated film) is preferably 2×10 8 ~3×10 8 Pa. In this embodiment, both E’(90) in the MD of the laminated film and E’(90) in the TD of the laminated film are preferably 2×10 8 ~3×10 8 Pa.

[0033] <E’(140)> The E’(140) of the laminated film is not particularly limited as long as E’(90) / E’(140) is 6 or more, but it is preferably 2.5×10 7 ~3.5×10 7 Pa. In this embodiment, when the direction of the stress applied to the laminated film during the measurement of E'(140) is aligned with the MD of the laminated film, E'(140) (i.e., E'(140) at the MD of the laminated film) is 2.5 × 10 7 ~3.5×10 7 Pa is preferable. In this embodiment, when the direction of the stress applied to the laminated film during the measurement of E'(140) is aligned with the TD of the laminated film, E'(140) (i.e., E'(140) at the TD of the laminated film) is 2.5 × 10 7 ~3.5×10 7 Pa is preferable. In this embodiment, E'(140) in the MD of the laminated film and E'(140) in the TD of the laminated film are both 2.5 × 10 7 ~3.5×10 7 Pa is preferable.

[0034] Examples of laminated films used for dynamic viscoelasticity (DMA) measurements include those with a width of 4 mm and a length of 5 cm or more. Therefore, the object of dynamic viscoelasticity measurement may be a test piece cut from the target laminated film. For dynamic viscoelasticity measurements, it is preferable to place the laminated film (test specimen) in the measuring device so that the length of the measurement target area is 2 cm, and then heat the laminated film (test specimen) at a heating rate of 3°C / min to perform the dynamic viscoelasticity measurement. Under these conditions, E'(90) and E'(140) can be measured with higher accuracy. It is preferable to measure E'(90) and E'(140) with the deformation mode set to tensile mode.

[0035] The E'(90) / E'(140) of the laminated film can be adjusted by adjusting the type and content of the components contained in each layer constituting the laminated film. In particular, it can be easily adjusted by adjusting the type and content of the ionomer contained in the buffer layer described later.

[0036] <Easy Peel Layer> The easy-peel layer (easy-peel layer 11 in the laminated film 1 shown in Figure 1) is a layer for sealing the laminated film to the object to be sealed, and is an easy-peel type sealant layer that can be easily peeled off from the object to be sealed at the desired timing after sealing. Furthermore, the Easy Peel layer is adjacent to the buffer layer.

[0037] The easy-peel layer preferably has transparency.

[0038] The easy-peel layer may contain only the components that exhibit easy-peel properties (for example, the two incompatible polyolefins described later), or it may contain the components that exhibit easy-peel properties and other components.

[0039] The easy-peel layer contains one component that exhibits easy-peel properties, and the other components may each consist of only one type or two or more types. If there are two or more types, their combination and ratio can be arbitrarily selected according to the purpose.

[0040] Examples of the easy-peel layer include a layer that exhibits peelability due to cohesive failure. For example, such an easy-peel layer may include a layer containing two incompatible polyolefins as components that exhibit easy-peel properties.

[0041] Examples of the two immiscible polyolefins included in the easy-peel layer include ethylene-based polymers and propylene-based polymers. In other words, an example of an easy-peel layer is a layer containing ethylene-based polymers and propylene-based polymers.

[0042] Examples of the ethylene-based polymer contained in the easy-peel layer include polyethylene (ethylene homopolymer, PE) and ethylene-based copolymers. The ethylene copolymer comprises structural units derived from ethylene and structural units derived from monomers other than ethylene.

[0043] Examples of polyethylene included in the easy-peel 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 embodiment, the densities of low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), and metallocene-catalyzed linear low-density polyethylene (mLLDPE) are 0.91 g / cm³. 3 More than 0.93g / cm 3 It is less than. The density of medium-density polyethylene (MDPE) is 0.93 g / cm³. 3 More than 0.942g / cm 3 It is less than. The density of high-density polyethylene (HDPE) is 0.942 g / cm³. 3 That's all.

[0045] Examples of ethylene-based copolymers included in the Easy Peel layer include ethylene-vinyl acetate copolymer (EVA), 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), and ethylene-ethyl acrylate-maleic anhydride copolymer (E-EA-MAH).

[0046] The easy-peel layer preferably contains one or more ethylene-based polymers selected from the group consisting of low-density polyethylene, linear low-density polyethylene, and metallocene-catalyzed linear low-density polyethylene. The easy-peel properties of such an easy-peel layer are better.

[0047] Examples of the propylene-based polymer contained in the easy-peel layer include homopolypropylene (propylene homopolymer, hPP) and propylene-based copolymers. The propylene copolymer comprises structural units derived from propylene and structural units derived from monomers other than propylene.

[0048] Examples of propylene-ethylene copolymers included in the easy-peel layer include propylene-ethylene random copolymers (also known as polypropylene random copolymer, rPP) and propylene-ethylene block copolymers (also known as polypropylene block copolymer, bPP).

[0049] The easy-peel layer preferably contains one or more propylene-based polymers selected from the group consisting of homopolypropylene and propylene-ethylene random copolymers. The easy-peel properties of such an easy-peel layer are better.

[0050] In an easy-peel layer containing an ethylene polymer and a propylene polymer, the ratio of the content of the ethylene polymer (parts by mass) to the total content (parts by mass) of the ethylene polymer ([Ethylene polymer content in the easy-peel layer (parts by mass)] / ([Ethylene polymer content in the easy-peel layer (parts by mass)] + [Propylene polymer content in the easy-peel layer (parts by mass)]) × 100) is preferably 30 to 90% by mass, and may be, for example, 40 to 90% by mass, 50 to 85% by mass, or 60 to 80% by mass. When the ratio is above the lower limit, the easy-peel properties of the easy-peel layer are improved. When the ratio is below the upper limit, the peel strength is more stable. The aforementioned ratio is usually the same as the ratio of the content of ethylene polymer (parts by mass) to the total content (parts by mass) of ethylene polymer and propylene polymer in the easy-peel layer forming composition described later ([Content of ethylene polymer in the easy-peel layer forming composition (parts by mass)] / ([Content of ethylene polymer in the easy-peel layer forming composition (parts by mass)] + [Content of propylene polymer in the easy-peel layer forming composition (parts by mass)]) × 100). The relationship between the content of a component in any of the layers constituting the laminated film and the content of that component in the composition used to form that layer is the same for layers other than the easy-peel layer, as will be described later.

[0051] The other components included in the Easy Peel layer are not particularly limited, as long as the effects of the Easy Peel layer are not impaired. Examples of the other components mentioned above include additives known in the field. Examples of the aforementioned additives include antifogging agents, antiblocking agents, antioxidants, antistatic agents, nucleating agents, inorganic particles, viscosity reducers, viscosity thickeners, heat stabilizers, lubricants, infrared absorbers, ultraviolet absorbers, and the like.

[0052] In the easy-peel layer, the ratio of the content (parts by mass) of the component that exhibits easy-peel properties to the total mass (parts by mass) of the easy-peel layer ([Content of the component that exhibits easy-peel properties in the easy-peel layer (parts by mass)] / [Total mass (parts by mass) of the easy-peel layer] × 100) is preferably 80% by mass or more, more preferably 90% by mass or more, and may be, for example, 95% by mass or more, or 97% by mass or more. The easy-peel properties of the easy-peel layer are improved when the ratio is equal to or greater than the lower limit. Here, if the "component that exhibits easy-peel properties" is the "two types of incompatible polyolefins" mentioned above, then the "content (parts by mass) of the component that exhibits easy-peel properties" is the "total content (parts by mass) of the two types of incompatible polyolefins". On the other hand, the aforementioned ratio is 100% by mass or less. The aforementioned ratio is typically the same as the ratio of the content of the component that exhibits easy-peel properties (parts by mass) to the total content of the component that does not vaporize at room temperature (parts by mass) in the easy-peel layer-forming composition described later ([Content of the component that exhibits easy-peel properties in the easy-peel layer-forming composition (parts by mass)] / [Total content of the component that does not vaporize at room temperature (parts by mass)] × 100). The relationship between the content of a component in any of the layers constituting the laminated film and the content of that component in the composition used to form that layer is the same for layers other than the easy-peel layer, as will be described later.

[0053] The easy-peel layer may consist of one layer (single layer) or of two or more layers. If the easy-peel layer consists of multiple layers, these layers may be identical or different, and the combination of these layers is not particularly limited as long as it does not impair the effects of the present invention.

[0054] In this specification, not only in the case of the Easy Peel layer, "multiple layers may be identical or different from one another" means "all layers may be identical, all layers may be different, or only some layers may be identical," and further, "multiple layers are different from one another" means "at least one of the constituent materials and thickness of each layer is different from the other."

[0055] The thickness of the easy-peel layer is preferably 3 to 10 μm, and may be, for example, 3 to 6 μm, 5 to 8 μm, or 7 to 10 μm. A thickness of the easy-peel layer greater than or equal to the lower limit improves the easy-peel properties of the easy-peel layer. A thickness of the easy-peel layer less than or equal to the upper limit allows for a thinner laminated film. In this specification, "thickness of the easy-peel layer" refers to the total thickness of the easy-peel layer. For example, the thickness of an easy-peel layer consisting of multiple layers refers to the total thickness of all the layers that make up the easy-peel layer. This also applies to layers other than the easy-peel layer, as described later.

[0056] The ratio of the thickness of the easy-peel layer to the total thickness of the laminated film ([thickness of easy-peel layer] / [total thickness of laminated film] × 100) is preferably 6 to 20%, and may be, for example, 6 to 12%, 10 to 16%, or 14 to 20%. Having this ratio within this range provides the same effect as when the thickness of the easy-peel layer is within the above range.

[0057] In this specification, the ratio of the thickness of each layer to the total thickness of the laminated film is described, not limited to the case of an easy-peel layer. However, in this embodiment, the sum of the ratios of all layers in the laminated film shall not exceed 100%.

[0058] <Buffer layer> The buffer layer (buffer layer 12 in the laminated film 1 shown in Figure 1) is adjacent to the easy-peel layer and is a layer that enables uniform sealing in the easy-peel layer when manufacturing a package by sealing the laminated films together, or the laminated films together with other films or sheets, thereby suppressing variations in the seal strength in the easy-peel layer. Furthermore, as described above, the buffer layer facilitates the adjustment of E'(90) / E'(140).

[0059] The buffer layer is preferably transparent.

[0060] The buffer layer contains ionomer (ION). The buffer layer may contain only the ionomer, or it may contain the ionomer and other components.

[0061] The ionomer contained in the buffer layer and the other components may each consist of only one type or two or more types, and if there are two or more types, their combination and ratio can be arbitrarily selected according to the purpose.

[0062] In this specification, "ionomer" means a copolymer of ethylene and one or more small amounts of monomers having acidic groups, wherein the acidic groups dissociate to generate anionic groups, and such copolymer forms an ionic crosslinking structure by the formation of a salt between the anionic groups and metal ions.

[0063] Examples of the acidic group include a carboxyl group, and examples of monomers having the acidic group include acrylic acid, methacrylic acid, maleic acid, and the like.

[0064] Examples of the aforementioned metal ions include sodium ions and zinc ions. In this specification, ionomers containing sodium ions as metal ions may be referred to as "sodium-based ionomers," and ionomers containing zinc ions as metal ions may be referred to as "zinc-based ionomers."

[0065] The melt flow rate (MFR, as sometimes referred to herein) of the ionomer contained in the buffer layer, measured in accordance with JIS K 7210:1999, is preferably 0.5 to 5 g / 10 min, more preferably 0.5 to 3 g / 10 min, and may be, for example, 0.5 to 2.5 g / 10 min or 1 to 3 g / 10 min. Using such an ionomer enhances the aforementioned effects of the buffer layer (the effect of suppressing variations in seal strength in the easy-peel layer, and the effect of facilitating the adjustment of E'(90) / E'(140); the same applies hereinafter).

[0066] The density of the ionomer contained in the buffer layer, measured in accordance with JIS K 7112:1999, is 0.91–0.97 g / cm³. 3Preferably, it is 0.91 to 0.95 g / cm³. 3 , and 0.93~0.97 g / cm³ 3 Either of these may be used. Using such an ionomer enhances the aforementioned effects exhibited by the buffer layer.

[0067] The tensile fracture stress of the ionomer contained in the buffer layer, measured in accordance with JIS K 7161-1:2014, is preferably 20 to 40 MPa, and may be, for example, 20 to 30 MPa, 25 to 35 MPa, or 30 to 40 MPa. Using such an ionomer enhances the aforementioned effects exhibited by the buffer layer.

[0068] The Vicat softening temperature of the ionomer contained in the buffer layer, as measured in accordance with JIS K 7206:1999, is preferably 60 to 86°C, and may be, for example, 60 to 70°C, 68 to 78°C, or 76 to 86°C. Using such an ionomer enhances the aforementioned effects exhibited by the buffer layer.

[0069] The flexural rigidity of the ionomer contained in the buffer layer, as measured in accordance with JIS K 7106:1995, is preferably 150 to 310 MPa, and may be, for example, 150 to 250 MPa, 180 to 280 MPa, or 210 to 310 MPa. Using such an ionomer enhances the aforementioned effects exhibited by the buffer layer.

[0070] The other components included in the buffer layer are not particularly limited, as long as the function of the buffer layer is not impaired. Other components included in the buffer layer include, for example, the same additives mentioned earlier as other components included in the easy-peel layer.

[0071] In the buffer layer, the ratio of the ionomer content (parts by mass) to the total mass (parts by mass) of the buffer layer is preferably 80% by mass or more, more preferably 90% by mass or more, and may be, for example, 95% by mass or more, or 97% by mass or more. The effect exhibited by the buffer layer described above is enhanced when the ratio is above the lower limit. On the other hand, the aforementioned ratio is 100% by mass or less.

[0072] The buffer layer may consist of one layer (single layer) or of two or more layers. If the buffer layer consists of multiple layers, these layers may be identical or different, and the combination of these layers is not particularly limited as long as it does not impair the effects of the present invention.

[0073] The thickness of the buffer layer is preferably 5 to 12 μm, and may be, for example, 5 to 8 μm, 7 to 10 μm, or 9 to 12 μm. A buffer layer thickness greater than or equal to the lower limit enhances the effects exhibited by the buffer layer. A buffer layer thickness less than or equal to the upper limit allows for a thinner laminated film.

[0074] The ratio of the buffer layer thickness to the total thickness of the laminated film is preferably 10-24%, and may be, for example, 10-16%, 14-20%, or 18-24%. Having this ratio within this range provides the same effects as when the buffer layer thickness is within the above range.

[0075] <Outer layer> The outer layer (outer layer 13 in the laminated film 1 shown in Figure 1) has rigidity and is a layer for improving the rigidity of the laminated film.

[0076] The outer layer is preferably transparent.

[0077] The outer layer contains amorphous polyester. Having such an outer layer further enhances the laminated film's conformability to the mold, improving its moldability, and also increases its glossiness when viewed from the outer layer side, thus improving its appearance.

[0078] The outer layer may contain only amorphous polyester, or it may contain amorphous polyester and other components.

[0079] The amorphous polyester contained in the outer layer and the other components may each consist of only one type or two or more types, and if there are two or more types, their combination and ratio can be arbitrarily selected according to the purpose.

[0080] Examples of preferred amorphous polyesters for the outer layer include glycol-modified polyethylene terephthalate (PETG), and it is preferable that the outer layer, as an amorphous polyester, contains at least glycol-modified polyethylene terephthalate. The amorphous polyester being glycol-modified polyethylene terephthalate enhances the rigidity, moldability, and gloss of the laminated film.

[0081] The glycol-modified polyethylene terephthalate is a polyester having a structure in which some of the structural units derived from ethylene glycol are replaced with structural units derived from cyclohexanedimethanol in polyethylene terephthalate; that is, it is a copolymer of terephthalic acid, ethylene glycol, and cyclohexanedimethanol.

[0082] The other components contained in the outer layer are not particularly limited, as long as the function of the outer layer is not impaired. Other components included in the outer layer include, for example, the same additives mentioned earlier as other components included in the Easy Peel layer.

[0083] In the outer layer, the ratio of amorphous polyester content (parts by mass) to the total mass (parts by mass) of the outer layer is preferably 80% by mass or more, more preferably 90% by mass or more, and may be, for example, 95% by mass or more, or 97% by mass or more. The above-mentioned effects exhibited by the outer layer are enhanced when the ratio is above the lower limit. On the other hand, the aforementioned ratio is 100% by mass or less.

[0084] When the outer layer is an amorphous polyester and contains at least glycol-modified polyethylene terephthalate, the ratio of the glycol-modified polyethylene terephthalate content (parts by mass) to the amorphous polyester content (parts by mass) in the outer layer is preferably 60% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, and particularly preferably 90% by mass or more. For example, it may be any of 95% by mass or more and 97% by mass or more. The above-mentioned effects exhibited by the outer layer are enhanced when the ratio is above the lower limit. On the other hand, the aforementioned ratio is 100% by mass or less.

[0085] The outer layer may consist of one layer (single layer) or of two or more layers. If the outer layer consists of multiple layers, these layers may be identical or different, and the combination of these layers is not particularly limited as long as it does not impair the effects of the present invention.

[0086] The thickness of the outer layer is preferably 12 to 20 μm, and may be, for example, 12 to 16 μm, 14 to 18 μm, or 16 to 20 μm. A thickness of the outer layer greater than or equal to the lower limit enhances the effects exhibited by the outer layer. A thickness of the outer layer less than or equal to the upper limit allows for a thinner laminated film.

[0087] The ratio of the outer layer thickness to the total thickness of the laminated film is preferably 24-40%, and may be, for example, 24-32%, 28-36%, or 32-40%. Having this ratio within this range provides the same effects as when the outer layer thickness falls within the above range.

[0088] <Pinhole-resistant layer> Preferably, the laminated film further includes a pinhole-resistant layer between the buffer layer and the outer layer. The aforementioned pinhole-resistant layer (pinhole-resistant layer 14 in the laminated film 1 shown in Figure 1) is a layer that has high strength, suppresses the occurrence of pinholes in the laminated film (has pinhole resistance), and protects the structure of the laminated film.

[0089] The pinhole-resistant layer is preferably transparent.

[0090] The pinhole-resistant layer is preferably a resin layer containing resin. Examples of the resin included in the pinhole-resistant layer include polyamide. In other words, it is preferable that the laminated film further comprises a pinhole-resistant layer containing polyamide.

[0091] The pinhole-resistant layer may, for example, contain only polyamide, or it may contain polyamide and other components.

[0092] If the pinhole-resistant layer contains polyamide, the polyamide and the other components contained in the pinhole-resistant layer may each be one type or two or more types, and if there are two or more types, their combination and ratio can be arbitrarily selected according to the purpose.

[0093] Examples of polyamides that can be included in the pinhole-resistant layer include cyclic lactams (lactams with 3 or more ring members), amino acids, or polyamides obtained by polymerizing or copolymerizing nylon salts obtained by the reaction of diamines and dicarboxylic acids.

[0094] Examples of the cyclic lactams include ε-caprolactam, ω-enantractam, ω-laurolactam, α-pyrrolidone, and α-piperidone.

[0095] Examples of the aforementioned amino acids include 6-aminocaproic acid, 7-aminoheptanoic acid, 9-aminononanoic acid, 11-aminoundecanoic acid, and 12-aminododecanoic acid.

[0096] Examples of the diamines that form 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, isophorone diamine, piperazine, bis(4-aminocyclohexyl)methane, and 2,2-bis-(4-aminocyclohexyl)propane; Examples include aromatic diamines such as metaxylylenediamine and paraxylylenediamine.

[0097] 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, undecanedionic acid, and dodecanedionic acid; Alicyclic carboxylic acids such as hexahydroterephthalic acid and hexahydroisophthalic acid; Examples include aromatic dicarboxylic acids such as 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.

[0098] More specifically, the polyamides include, 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, copolymers of 6-nylon and 66-nylon (nylon 6 / 66), copolymers of 6-nylon and 610-nylon, copolymers of 6-nylon and 611-nylon, copolymers of 6-nylon and 12-nylon (nylon 6 / 12), and copolymers of 6-nylon and 612-nylon. Examples include 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, and copolymers of 66-nylon, 6T-nylon and 6I-nylon.

[0099] The polyamide is preferably 6-nylon (sometimes abbreviated as "Ny6" in this specification), 12-nylon, 66-nylon, nylon 6 / 66, nylon 6 / 12, or nylon 6 / 66 / 12, in terms of heat resistance, mechanical strength, and availability.

[0100] The other components included in the pinhole-resistant layer are not particularly limited, as long as the pinhole-resistant layer's function is not impaired. Other components included in the pinhole-resistant layer include, for example, the same additives mentioned earlier as other components included in the easy-peel layer.

[0101] When the pinhole-resistant layer contains polyamide, the ratio of the polyamide content (parts by mass) to the total mass (parts by mass) of the pinhole-resistant layer is preferably 80% by mass or more, more preferably 90% by mass or more, and may be, for example, 95% by mass or more, or 97% by mass or more. The above-mentioned effect exhibited by the pinhole-resistant layer is enhanced when the ratio is above the lower limit. On the other hand, the aforementioned ratio is 100% by mass or less.

[0102] The pinhole-resistant layer may consist of one layer (single layer) or of two or more layers. If the pinhole-resistant layer consists of multiple layers, these layers may be identical or different, and the combination of these layers is not particularly limited as long as it does not impair the effects of the present invention.

[0103] The thickness of the pinhole-resistant layer is preferably 5 to 12 μm, and may be, for example, 5 to 8 μm, 7 to 10 μm, or 9 to 12 μm. A thickness of the pinhole-resistant layer greater than or equal to the lower limit enhances the aforementioned effects of the pinhole-resistant layer. A thickness of the pinhole-resistant layer less than or equal to the upper limit allows for a thinner laminated film.

[0104] The ratio of the thickness of the pinhole-resistant layer to the total thickness of the laminated film is preferably 10-24%, and may be, for example, 10-16%, 14-20%, or 18-24%. Having this ratio within this range provides the same effect as when the thickness of the pinhole-resistant layer is within the above range.

[0105] <Oxygen barrier layer> Preferably, the laminated film further includes an oxygen barrier layer between the buffer layer and the outer layer. The oxygen barrier layer (oxygen barrier layer 15 in the laminated film 1 shown in Figure 1) has oxygen barrier properties (in other words, properties that suppress the permeation of oxygen gas) and is a layer that imparts oxygen barrier properties to the laminated film.

[0106] The oxygen barrier layer is preferably transparent.

[0107] The oxygen barrier layer is preferably a resin layer containing resin. Examples of the resin contained in the oxygen barrier layer include ethylene-vinyl alcohol copolymer (EVOH, also known as ethylene-vinyl acetate copolymer saponified). In other words, it is preferable that the laminated film further comprises an oxygen barrier layer containing ethylene-vinyl alcohol copolymer.

[0108] The oxygen barrier layer may, for example, contain only an ethylene-vinyl alcohol copolymer, or it may contain an ethylene-vinyl alcohol copolymer and other components.

[0109] When the oxygen barrier layer contains an ethylene-vinyl alcohol copolymer, the ethylene-vinyl alcohol copolymer and the other components contained in the oxygen barrier layer may each consist of only one type or two or more types. If there are two or more types, their combination and ratio can be arbitrarily selected according to the purpose.

[0110] In the ethylene-vinyl alcohol copolymer contained in the oxygen barrier layer, the ratio of the amount of constituent units derived from ethylene (moles) to the total amount of constituent units in the ethylene-vinyl alcohol copolymer (sometimes referred to as the "ethylene copolymerization ratio" in this specification) is preferably 30 to 50 mol%, and may be, for example, 30 to 45 mol% and 30 to 40 mol%.

[0111] The other components included in the oxygen barrier layer are not particularly limited, as long as the function of the oxygen barrier layer is not impaired. Other components included in the oxygen barrier layer include, for example, the same additives mentioned earlier as other components included in the easy-peel layer.

[0112] When the oxygen barrier layer contains an ethylene-vinyl alcohol copolymer, the ratio of the ethylene-vinyl alcohol copolymer content (parts by mass) to the total mass (parts by mass) of the oxygen barrier layer is preferably 80% by mass or more, more preferably 90% by mass or more, and may be, for example, 95% by mass or more, or 97% by mass or more. The above-mentioned effects exhibited by the oxygen barrier layer are enhanced when the ratio is above the lower limit. On the other hand, the aforementioned ratio is 100% by mass or less.

[0113] The oxygen barrier layer may consist of one layer (single layer) or of two or more layers. If the oxygen barrier layer consists of multiple layers, these layers may be identical or different, and the combination of these layers is not particularly limited as long as it does not impair the effects of the present invention.

[0114] The thickness of the oxygen barrier layer is preferably 3 to 10 μm, and may be, for example, 3 to 6 μm, 5 to 8 μm, or 7 to 10 μm. A thickness of the oxygen barrier layer greater than or equal to the lower limit enhances the oxygen barrier properties of the oxygen barrier layer (laminated film). A thickness of the oxygen barrier layer less than or equal to the upper limit allows for a thinner laminated film.

[0115] The ratio of the thickness of the oxygen barrier layer to the total thickness of the laminated film is preferably 6 to 20%, and may be, for example, 6 to 12%, 10 to 16%, or 14 to 20%. Having this ratio within this range provides the same effects as when the thickness of the oxygen barrier layer is within the above range.

[0116] <Adhesive layer> The laminated film may include an adhesive layer. The adhesive layer is a layer in the laminated film that adheres two adjacent layers and contains components that exhibit adhesive properties. A laminated film with an adhesive layer has a more stable structure.

[0117] The position of the adhesive layer in a laminated film is not particularly limited, as long as it is not the outermost layer of the laminated film. The adhesive layer in the laminated film may be located in one place or in two or more places. If the adhesive layer is located in two or more places in the laminated film, these two or more adhesive layers may be identical or different from each other.

[0118] If the laminated film includes an adhesive layer, it is preferable that the adhesive layer (first adhesive layer 161 in the laminated film 1 shown in Figure 1) is provided between the buffer layer and the pinhole-resistant layer, and that the adhesive layer (second adhesive layer 162 in the laminated film 1 shown in Figure 1) is provided between the oxygen barrier layer and the outer layer. However, these are just examples of the placement of the adhesive layers.

[0119] The adhesive layer is preferably transparent.

[0120] The adhesive layer is preferably a resin layer containing an adhesive resin (containing an adhesive resin as a component that exhibits adhesive properties).

[0121] The adhesive layer may contain only components that exhibit adhesive properties, or it may contain components that exhibit adhesive properties and other components.

[0122] The adhesive component (e.g., adhesive resin) contained in the adhesive layer and the other components may each consist of only one type or two or more types. If there are two or more types, their combination and ratio can be arbitrarily selected according to the purpose.

[0123] Examples of the adhesive resin include well-known materials such as polyolefins. The polyolefin is a resin having structural units derived from an olefin, and may be a modified polyolefin such as an acid-modified polyolefin having an acidic group. Examples of polyolefins include ethylene copolymers, propylene copolymers, butene copolymers, modified products of these copolymers (in other words, modified copolymers), acid-modified polyethylene, and acid-modified polypropylene. The ethylene copolymer, which is an adhesive resin, comprises structural units derived from ethylene and structural units derived from monomers other than ethylene. The propylene copolymer, which is an adhesive resin, comprises structural units derived from propylene and structural units derived from monomers other than propylene. The butene-based copolymer, which is an adhesive resin, comprises structural units derived from butene and structural units derived from monomers other than butene.

[0124] Other components included in the adhesive layer include, for example, antioxidants.

[0125] In the adhesive layer, the ratio of the content (parts by mass) of the adhesive component to the total mass (parts by mass) of the adhesive layer is preferably 80% by mass or more, and more preferably 90% by mass or more. When the ratio is above the lower limit, the adhesiveness of the adhesive layer is further enhanced. On the other hand, the aforementioned ratio is 100% by mass or less.

[0126] The adhesive layer at each location may consist of one layer (single layer) or of two or more layers. If the adhesive layer consists of multiple layers, these layers may be identical or different, and the combination of these layers is not particularly limited as long as it does not impair the effects of the present invention.

[0127] The thickness of the adhesive layer at each location is preferably 1 to 10 μm, and may be, for example, 1 to 7 μm. When the thickness of the adhesive layer is greater than or equal to the lower limit, the adhesive layer has better adhesion. When the thickness of the adhesive layer is less than or equal to the upper limit, the thickness of the laminated film can be made thinner.

[0128] The ratio of the thickness of the adhesive layer at each location to the total thickness of the laminated film is preferably 2 to 20%, and may be, for example, 2 to 14%. Having this ratio within this range provides the same effects as when the thickness of the adhesive layer is within the above range.

[0129] <Other layers> The types, number, and positions of the other layers, the number of layers per type, and the thickness, etc., are not particularly limited and can be arbitrarily selected according to the purpose.

[0130] <Other configurations of laminated films> The thickness of the laminated film is not particularly limited, but in order to further enhance the effect of this embodiment, which is that the sealing body has good cutability even when the thickness of the laminated film is thin, it is preferably 60 μm or less, more preferably 56 μm or less, and for example, it may be 52 μm or less. On the other hand, the thickness of the laminated film is preferably 40 μm or more, as this makes its manufacture easier. In one embodiment, the thickness of the laminated film may be any of 40-60 μm, 40-56 μm, or 40-52 μm. However, these are just examples of laminated film thicknesses.

[0131] It is preferable that the laminated film is transparent, i.e., that the laminated film is a transparent laminated film, because all the layers of the laminated film are transparent. In a package obtained using such a laminated film, the packaged contents can be easily seen through the laminated film or its molded form.

[0132] <An example of a laminated film> A preferred example of a laminated film of this embodiment is a laminated film comprising an easy-peel layer, a buffer layer adjacent to the easy-peel layer, and an outer layer, The buffer layer contains an ionomer, The outer layer contains amorphous polyester, The aforementioned easy-peel layer comprises an ethylene polymer and a propylene polymer. In the buffer layer, the ratio of the ionomer content to the total mass of the buffer layer is 80% by mass or more. When the storage modulus E'(90) at 90°C and the storage modulus E'(140) at 140°C are measured by dynamic viscoelasticity measurement of the laminated film, and E'(90) / E'(140) is 6 or greater, A laminated film having a thickness of 60 μm or less is an example.

[0133] A more preferred example of the laminated film of this embodiment is a laminated film comprising an easy-peel layer, a buffer layer adjacent to the easy-peel layer, and an outer layer, The buffer layer contains an ionomer, The outer layer comprises at least glycol-modified polyethylene terephthalate as an amorphous polyester. The aforementioned easy-peel layer comprises an ethylene polymer and a propylene polymer. In the buffer layer, the ratio of the ionomer content to the total mass of the buffer layer is 80% by mass or more. In the outer layer, the ratio of the glycol-modified polyethylene terephthalate content (parts by mass) to the amorphous polyester content (parts by mass) is 60% by mass or more. When the storage modulus E'(90) at 90°C and the storage modulus E'(140) at 140°C are measured by dynamic viscoelasticity measurement of the laminated film, and E'(90) / E'(140) is 6 or greater, A laminated film having a thickness of 60 μm or less is an example.

[0134] Another example of a more preferred laminated film of this embodiment is a laminated film comprising an easy-peel layer, a buffer layer adjacent to the easy-peel layer, and an outer layer, The buffer layer contains an ionomer, The outer layer contains amorphous polyester, The aforementioned easy-peel layer comprises an ethylene polymer and a propylene polymer. In the buffer layer, the ratio of the ionomer content to the total mass of the buffer layer is 80% by mass or more. The laminated film further comprises a pinhole-resistant layer containing polyamide and an oxygen barrier layer containing an ethylene-vinyl alcohol copolymer between the buffer layer and the outer layer. When the storage modulus E'(90) at 90°C and the storage modulus E'(140) at 140°C are measured by dynamic viscoelasticity measurement of the laminated film, and E'(90) / E'(140) is 6 or greater, The ratio of the thickness of the buffer layer to the total thickness of the laminated film is 10-24%. A laminated film having a thickness of 60 μm or less is an example.

[0135] <<Manufacturing method for laminated film>> The laminated film of this embodiment can be manufactured, for example, by a feed block method in which several extruders are used to melt-extrude resins or resin compositions that will form each layer, a co-extrusion T-die method such as a multi-manifold method, or an air-cooled or water-cooled co-extrusion inflation method.

[0136] The resin composition that forms any of the layers in the laminated film can be manufactured by adjusting the types and amounts of the constituent components so that the layer to be formed contains the desired components (constituent materials) in the desired amounts. For example, the ratio of the amounts of components that do not vaporize at room temperature in the resin composition is usually the same as the ratio of the amounts of those components in the layer formed from this resin composition.

[0137] Examples of resin compositions for forming an easy-peel layer include a resin composition comprising a component that exhibits easy-peel properties (for example, the two incompatible polyolefins mentioned above) and, if necessary, the other components.

[0138] Examples of resin compositions for forming a buffer layer (which may be referred to as "buffer layer forming compositions" in this specification) include resin compositions comprising an ionomer and, optionally, the other components mentioned above.

[0139] Examples of resin compositions for forming the outer layer (sometimes referred to as "outer layer forming composition" in this specification) include resin compositions comprising amorphous polyester and, if necessary, the other components mentioned above.

[0140] Examples of resin compositions for forming a pinhole-resistant layer (which may be referred to herein as "pinhole-resistant layer-forming composition") include a resin composition comprising a polyamide and, optionally, the other components mentioned above.

[0141] Examples of resin compositions for forming an oxygen barrier layer (which may be referred to as "oxygen barrier layer forming compositions" in this specification) include resin compositions comprising an ethylene-vinyl alcohol copolymer and, if necessary, the other components mentioned above.

[0142] Examples of resin compositions for forming an adhesive layer (sometimes referred to as "adhesive layer forming composition" in this specification) include a resin composition comprising the above-mentioned adhesive component (e.g., an adhesive resin) and, if necessary, the other components.

[0143] The long laminated film, immediately after being fed out of manufacturing equipment such as an extruder, is at a high temperature, and is then cooled before being wound into a roll. The winding speed of the laminated film at this time is preferably 50 to 100 m / min. Unlike conventional resin films, the laminated film of this embodiment suppresses neck-in during winding. For example, when the winding speed of the laminated film is within this range, the effect of suppressing neck-in is high despite the high winding speed.

[0144] <<Packaging>> A packaging body according to one embodiment of the present invention is constructed using the laminated film according to the above embodiment of the present invention. Since the packaging of this embodiment is constructed using the laminated film, it can be easily and stably manufactured.

[0145] The packaging of this embodiment preferably comprises a molded body of the laminated film, and more preferably comprises a bottom material which is a molded body of the laminated film. The molded body in such packaging, by using the laminated film, reflects the shape of the mold to a high degree, achieves the desired shape with high precision, and has high moldability.

[0146] The packaging body of this embodiment is constructed using the laminated film, regardless of whether or not it includes a molded body of the laminated film. Therefore, it has high gloss when viewed from the side of the laminated film or its molded body, and has an excellent appearance.

[0147] The packaging of this embodiment is suitable for packaging food products, and is more suitable for packaging processed meat products such as ham and bacon.

[0148] A preferred packaging body is, for example, a packaging body comprising a lid and a bottom, which are sealed together, and the bottom is a molded body of the laminated film. Such a packaging body may be, for example, a deep-drawn packaging body, and such deep-drawn packaging bodies are suitable for forming a continuous pack by bonding multiple of them together with adhesive seals.

[0149] Figure 2 is a schematic cross-sectional view showing an example of the packaging according to this embodiment. In Figure 2, the same components as those shown in Figure 1 are denoted by the same reference numerals as in Figure 1, and their detailed explanations are omitted.

[0150] The packaging 101 shown in Figure 2 is composed of a bottom material 10 and a lid material 8. The base material 10 is a molded body of the laminated film 1 shown in Figure 1. However, in Figure 2, the distinction between each layer in the laminated film 1 that constitutes the base material 10 is omitted.

[0151] A recess 100 is formed in the base material 10. One side of the base material 10 (sometimes referred to as the "second side" in this specification) 10b and one side of the lid material 8 (sometimes referred to as the "second side" in this specification) 8b are both sealing surfaces, and they face each other in the packaging 101. In the packaging 101, the area of ​​the second surface 10b of the base material 10, excluding the area where the recess 100 is formed, and the area of ​​the second surface 8b of the lid material 8, closer to the periphery, are overlapped. At least the area near the periphery of the overlapped area of ​​the base material 10 and the lid material 8 (in other words, the non-storage area) is sealed to each other, thus forming the packaging 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. The contents 9 (in other words, the packaged item or the object to be packaged) are stored within this storage section 101a.

[0152] The second surface 10b of the base material 10 is the same as the second surface 11b of the easy-peel layer 11 in the laminated film 1. The other surface 10a of the base material 10 is the same as the first surface 13a of the outer layer 13 in the laminated film 1. The thickness of the flat portion of the base material 10 may be the same as the thickness of the multilayer film described above. In the base material 10, the depth of the recess 100 is preferably 3 to 15 mm, and more preferably 5 to 10 mm.

[0153] The lid material 8 may be made of a laminated film according to the above-described embodiment, including the laminated film 1, or it may be any other known lid material. Examples of known lid materials 8 include lid materials made of single-layer or multi-layer resin films.

[0154] The thickness of the lid material 8 is not particularly limited, but is preferably 40 to 100 μm, and more preferably 50 to 80 μm. When the thickness of the lid material 8 is above the lower limit, the strength of the lid material 8 is further improved. When the thickness of the lid material 8 is below the upper limit, the thickness of the lid material 8 is avoided to be excessive, and the thickness of the non-storage portion of the packaging body 101 becomes thinner. Here, "thickness of lid material 8" refers to the total thickness of lid material 8. For example, the thickness of lid material 8 consisting of multiple layers refers to the total thickness of all layers that make up lid material 8.

[0155] The packaging of this embodiment is not limited to the packaging 101 shown in Figure 2. For example, within the scope of the present invention, the packaging 101 may have some components modified, deleted, or added. For example, Figure 2 shows a package 101 where the base material is a molded body of the laminated film 1 shown in Figure 1. However, in the package of this embodiment, the base material may be a molded body of a laminated film other than the laminated film 1.

[0156] <<Manufacturing method for packaging>> The packaging of this embodiment can be manufactured by packaging the object to be packaged using the laminated film. Furthermore, the packaging of this embodiment can be manufactured in the same manner as conventional packaging, except that the laminated film is used instead of conventional resin film.

[0157] For example, a package (e.g., the package 101 shown in Figure 2) comprising a bottom material and a lid material obtained using the laminated film can be manufactured by the following method. In other words, a long base material is manufactured by forming recesses at multiple locations along the longitudinal direction of the long laminated film. The recesses can be formed by heat molding using a mold, for example, by deep drawing. The molding temperature during heat molding is preferably 80 to 100°C, and the molding time is preferably 0.5 to 2 seconds. During heat molding, the laminated film has high conformability to the mold, so the recesses reflect the shape of the mold to a high degree, and the desired shape is realized with high precision.

[0158] Next, the object to be packaged is placed in the recess of the base material, and the base material and the long lid material are heat-sealed to produce a long sealed body in which multiple storage compartments are continuously provided in the longitudinal direction. At this time, the inside of the storage compartments may be vacuum-degassed. The sealing temperature during heat sealing is preferably 130 to 150°C, and may be, for example, around 140°C. The sealing time and sealing pressure during heat sealing can be appropriately adjusted according to the sealing temperature, but usually the sealing time is preferably 0.5 to 2 seconds, and the sealing pressure is preferably 0.1 to 0.3 MPa. Because the base material is a molded body of the laminated film, the resulting long sealed body has high uniformity of the sealed area throughout the entire area, and the sealing performance of the base material is good.

[0159] Next, the sealing body is cut along its longitudinal direction to produce a package body for each storage compartment. The sealing body can be cut using known methods, such as using a cutting blade. Due to the effects of heating during heat sealing, the temperature of the sealing body at the time of cutting (cutting temperature) is typically 40 to 100°C, and may be as low as 90°C, for example. By using the laminated film in which E'(90) / E'(140) is 6 or more (the sealing body comprises a molded body of the laminated film), even if the thickness of the laminated film (in other words, the base material or the sealing body) is thin, cutting defects such as the presence of uncut areas in the sealing body (more specifically the base material) do not occur, the sealing body can be cut normally at the desired location, and the cutting performance of the sealing body is good. Based on the above, the desired packaging can be manufactured. [Examples]

[0160] The present invention will be described in more detail below with reference to specific examples. However, the present invention is not limited in any way to the examples shown below.

[0161] The resins used in each example or comparative example are as follows: LDPE(1): Low-density polyethylene (F222A, manufactured by Ube Maruzen Polyethylene Co., Ltd., density 0.922 g / cm³) 3 ) LDPE(2): Low-density polyethylene (Sumitomo Chemical Co., Ltd. "L211", density 0.924 g / cm³) 3 ) mLLDPE: Metallocene-catalyzed linear low-density polyethylene (Ube Maruzen Polyethylene Co., Ltd. "1520F", density 0.913 g / cm³) 3 ) rPP: Polypropylene random copolymer (propylene-ethylene random copolymer, Sumitomo Chemical Co., Ltd. "FL6737", melting point 130℃, MFR 6 / 10min) ION: Zinc-based ionomer (Mitsui Dow Polychemicals "1650") Ny6:6-Nylon (Manufactured by Ube Industries, Ltd., "1022B") EVOH: Ethylene-vinyl alcohol copolymer (Kuraray Co., Ltd. "J171B", copolymerization ratio of ethylene: 32 mol%) PETG: Glycol-modified polyethylene terephthalate (amorphous polyester, manufactured by SK Chemical Co., Ltd., "S2008") Modified PO(1): Modified polyolefin (adhesive resin, Mitsui Chemicals, Inc. "Admer® NF567") Modified PO(2): Modified polyolefin (adhesive resin, "Admer® SF741" manufactured by Mitsui Chemicals, Inc.)

[0162] The physical properties of the aforementioned ION (zinc-based ionomer) are as follows: Melting point: 97℃ Melt flow rate measured in accordance with JIS K 7210:1999: 1.5g / 10min Density measured in accordance with JIS K 7112:1999: 0.95 g / cm³ 3 Tensile fracture stress measured in accordance with JIS K 7161-1:2014: 30 MPa Vicat softening temperature measured in accordance with JIS K 7206:1999: 74°C Bending stiffness measured in accordance with JIS K 7106:1995: 250 MPa

[0163] [Example 1] <<Manufacturing of Laminated Films>> An easy-peel layer forming composition was prepared by mixing the aforementioned LDPE(1) (70 parts by mass) and the aforementioned rPP (30 parts by mass) at room temperature.

[0164] By co-extruding the easy-peel layer-forming composition, the ION, the modified PO(1), the Ny6, the EVOH, the modified PO(2), and the PETG in this order, a long laminated film (50 μm thick) with the configuration shown in Figure 1 was produced, consisting of an easy-peel layer (5.5 μm thick), a buffer layer (8.5 μm thick), a first adhesive layer (3 μm thick), a pinhole-resistant layer (8.5 μm thick), an oxygen barrier layer (4.5 μm thick), a second adhesive layer (4 μm thick), and an outer layer (16 μm thick), all laminated in this order in the thickness direction. At this time, the long laminated film fed from the extruder was sequentially wound into rolls by winding machines placed at intervals from the extruder. The winding speed was 80 m / min. In this laminated film, the easy-peel layer, buffer layer, first adhesive layer, pinhole-resistant layer, oxygen barrier layer, second adhesive layer, and outer layer are all unstretched layers.

[0165] <<Manufacturing of packaging>> <Manufacturing of lid materials> A linear low-density polyethylene (LLDPE) film (30 μm thick) was fabricated using the T-die extrusion method with "Ultzex ​​2022L" manufactured by Prime Polymer Co., Ltd. A biaxially oriented polypropylene film (OPP film, 20 μm thick), a biaxially oriented polyethylene terephthalate film (VM-PET film, 12 μm thick) with aluminum vapor deposition, and the above-mentioned LLDPE film (30 μm thick) were laminated together in this order using a dry lamination method to produce a long film (lid material, 62 μm thick) consisting of an outer layer (20 μm thick) made of the OPP film, an intermediate layer (12 μm thick) made of the VM-PET film, and a sealant layer (30 μm thick) made of the LLDPE film, which were laminated in this order in the thickness direction.

[0166] <Manufacturing of base materials> Using a continuous deep-draw packaging machine (Multivac "R-535"), the long roll of laminated film described above was deep-drawn at a molding temperature of 90°C and a molding time of 1 second. By repeatedly forming circular recesses with a depth of 6 mm and an opening diameter of 100 mm at multiple locations along the longitudinal direction of the laminated film, a long base material was produced.

[0167] <Manufacturing of packaging materials> Using a continuous deep-draw packaging machine (Multivac "R-535"), food (ham, 40g) was placed in the recess of the bottom material obtained above. Next, the sealant layer of the lid material and the easy-peel layer of the bottom material were placed opposite each other, sandwiching the food between the lid material and the bottom material. The inside of the storage section formed by the lid material and the bottom material was vacuum-degassed for 1 second, while the peripheral edges of the lid material and the bottom material were heat-sealed under the conditions of a sealing temperature of 140°C, a sealing time of 2 seconds, and a sealing pressure of 0.2 MPa. By continuously performing this heat-sealing of the lid material and bottom material for each storage section, a long sealed body with storage sections continuously arranged in the longitudinal direction was produced. Next, this sealing body was cut along its longitudinal direction with a cutting blade, one storage compartment at a time, to produce a total of six packaging bodies (vacuum packaging bodies and deep-drawn packaging bodies).

[0168] <<Evaluation of Laminated Films>> <Evaluation of the effect of suppressing neck-in in laminated films> During the manufacturing of the laminated film described above, the width of the laminated film immediately after being fed out of the extruder (in other words, the dimension at TD; the same applies hereafter) and the width of the laminated film after it had solidified due to subsequent cooling were measured simultaneously. That is, these widths were measured at different points on a long piece of laminated film. Then, the following formula (i) [Neck-in ratio of laminated film (%)] = ([Width of laminated film immediately after being fed out of the extruder] - [Width of laminated film after cooling and solidification]) / [Width of laminated film immediately after being fed out of the extruder] × 100 (i) Based on this, the neck-in ratio of the laminated film, which serves as an indicator of the superiority or inferiority of the neck-in suppression effect of the laminated film, was calculated. Furthermore, the neck-in suppression effect of the laminated film was evaluated according to the following criteria based on this neck-in ratio. The results are shown in Table 1. [Evaluation Criteria] A: The neck-in ratio of the laminated film is 15% or less, indicating a high effectiveness in suppressing neck-in. B: The neck-in ratio of the laminated film is over 15%, indicating that the effect of suppressing neck-in is not observed or is low.

[0169] <Calculation of E'(90) / E'(140) for laminated films> From the laminated film obtained above, test specimens with a width of 4 mm and a length of 5 cm or more were cut out. Using a dynamic viscoelasticity measuring device (Seiko Instruments "DMS6100"), the test specimens were placed in the sample holder so that the length of the measurement target area of ​​the test specimen was 2 cm. At this time, the MD of the test specimen was aligned with the direction of the stress applied to the test specimen. Next, in tensile mode, the test specimen was heated from 25°C to 200°C at a heating rate of 3°C / min. Within this temperature range, under conditions of a displacement of 5 μm and a vibration frequency of 1 Hz, E'(90) and E'(140) at the MD of the test specimen (laminated film) were measured, and E'(90) / E'(140) was calculated. The results are shown in Table 1. Furthermore, a separate test specimen was prepared, and the E'(90) and E'(140) values ​​at the TD of the test specimen (laminated film) were measured using the same method as described above, except that the TD of the test specimen was aligned with the direction of the stress applied to the test specimen. E'(90) / E'(140) was then calculated. The results are shown in Table 1.

[0170] <Evaluation of moldability of laminated films> From the base material obtained above, one recess was randomly selected, and the bent portion at the boundary between the bottom surface and the side surface in this recess was visually observed. Focusing on the degree of uniformity of the shape of the bent portion, the moldability of the laminated film was evaluated according to the following criteria. The results are shown in Table 1. [Evaluation Criteria] A: The shape of the bent portion is uniform throughout the entire area, and the moldability of the laminated film is good. B: In at least a portion of the bent portion, the shape of the bent portion is uneven, resulting in poor moldability of the laminated film.

[0171] <<Evaluation of the base material>> <Evaluation of sealing properties of the base material> One package was randomly selected from the six packages obtained above. The entire seal area of ​​the lid and bottom of this package was visually inspected, and the sealability of the bottom material was evaluated according to the following criteria, focusing on the shape of the seal area and whether or not the lid and bottom material had peeled off. The results are shown in Table 1. [Evaluation Criteria] A: The seal area exhibits high uniformity throughout, resulting in excellent sealing performance of the base material. B: In at least a portion of the sealing area, the sealing area is uneven, resulting in poor sealing performance of the base material.

[0172] <<Evaluation of the seal material>> <Evaluation of the cleavage properties of the seal> All packages obtained as described above were visually inspected to check for defects in the seal (manufacturing abnormalities of the package), and the cutability of the seal was evaluated according to the following criteria. The results are shown in Table 1. [Evaluation Criteria] A: No defects in the sealing material have occurred, and all packaging materials have been manufactured correctly. B: At least a portion of the seal material has a cutting defect, and the packaging material has not been manufactured properly.

[0173] <<Evaluation of packaging>> <Evaluation of curl resistance of packaging materials> The packaging obtained above was placed on a horizontal surface with its lid side in contact with a horizontal surface, and the height from the horizontal surface of the part of the packaging excluding the storage area that was the highest (hereinafter referred to as "maximum height") was measured. The maximum height was measured for all the packaging obtained above, and the curl resistance of the packaging was evaluated according to the following criteria. The results are shown in Table 1. [Evaluation Criteria] A: All packaging materials have a maximum height of 5 mm or less, and the packaging materials have high curl resistance. B: At least one package has a maximum height exceeding 5 mm, and the package has little to no curl resistance.

[0174] <<Manufacturing of laminated films and packaging materials, and evaluation of laminated films, base materials, seals, and packaging materials>> [Comparative Example 1] In the manufacturing of the laminated film, except that LDPE(2) was used instead of ION during the manufacturing of the laminated film, a long laminated film (thickness 50 μm) was manufactured in the same manner as in Example 1, with an easy-peel layer (thickness 5.5 μm), a buffer layer (thickness 8.5 μm), a first adhesive layer (thickness 3 μm), a pinhole-resistant layer (thickness 8.5 μm), an oxygen barrier layer (thickness 4.5 μm), a second adhesive layer (thickness 4 μm), and an outer layer (thickness 16 μm) being laminated in this order in the thickness direction. Then, in the same manner as in Example 1, except that the laminated film obtained here was used, a packaging body was manufactured, and the laminated film, base material, seal body, and packaging body were evaluated. The results are shown in Table 1.

[0175] [Comparative Example 2] In the manufacturing of the laminated film, a long laminated film (thickness 50 μm) was manufactured in the same manner as in Example 1, except that the mLLDPE was used instead of the ION during the manufacturing of the laminated film. The laminated film consisted of an easy-peel layer (thickness 5.5 μm), a buffer layer (thickness 8.5 μm), a first adhesive layer (thickness 3 μm), a pinhole-resistant layer (thickness 8.5 μm), an oxygen barrier layer (thickness 4.5 μm), a second adhesive layer (thickness 4 μm), and an outer layer (thickness 16 μm), which were laminated in this order in the thickness direction. Then, in the same manner as in Example 1, except that the laminated film obtained here was used, a packaging body was manufactured, and the laminated film, base material, seal body, and packaging body were evaluated. The results are shown in Table 1.

[0176] [Table 1]

[0177] As is clear from the results above, in Example 1, the thickness of the laminated film was 50 μm, which was thinner than conventional methods. However, the seal body made using this laminated film had good cutability, and the packaging body could be manufactured successfully. In Example 1, the buffer layer contained an ionomer, and the E'(90) / E'(140) ratio in the MD of the laminated film was 8.9, and the E'(90) / E'(140) ratio in the TD was 7.8, both of which were large.

[0178] Furthermore, in Example 1, neck-in of the laminated film was suppressed. Furthermore, in Example 1, the outer layer contained PETG, resulting in good moldability of the laminated film. Furthermore, in Example 1, the sealing properties of the base material and the curl resistance of the packaging were also good. In the packaging, curling was suppressed, including in the non-storage areas. Thus, the laminated film of Example 1 had particularly desirable properties.

[0179] In contrast, in Comparative Examples 1 and 2, although the thickness of the laminated film was 50 μm, the same as in Example 1, the cutability of the seal body made using this laminated film was poor, unlike in Example 1, and the packaging body could not be manufactured properly. In Comparative Example 1, the buffer layer contained LDPE instead of ionomer, and the E'(90) / E'(140) values ​​for both the MD and TD of the laminated film were 2.7, which was small. In Comparative Example 2, the buffer layer contained mLLDPE instead of ionomer, and the E'(90) / E'(140) ratio of the laminated film was 3.7 in the MD and 4.6 in the TD, both of which were small. [Industrial applicability]

[0180] The present invention can be used in the manufacture of food packaging, and is particularly suitable for the manufacture of thin packaging, and especially suitable for the manufacture of packaging when multiple thin packaging units are assembled into a continuous pack. [Explanation of symbols]

[0181] 1. Laminated film 11. Easy Peel Layer 12...Buffer layer 13...outer layer 14. Pinhole-resistant layer 15. Oxygen barrier layer 8...Lid material 10...Bottom material 101...Packaging

Claims

1. A laminated film comprising an easy-peel layer, a buffer layer adjacent to the easy-peel layer, and an outer layer, The buffer layer contains an ionomer, The outer layer contains amorphous polyester, A laminated film in which, when the storage modulus E'(90) at 90°C and the storage modulus E'(140) at 140°C are measured by dynamic viscoelasticity measurement of the laminated film, the ratio E'(90) / E'(140) is 6 or greater when the vibration frequency is 1 Hz.

2. The laminated film according to claim 1, wherein the thickness of the laminated film is 60 μm or less.

3. The laminated film according to claim 1 or 2, wherein the melt flow rate of the ionomer, as measured in accordance with JIS K 7210:1999, is 0.5 to 5 g / 10 min.

4. The laminated film according to claim 1 or 2, wherein the easy-peel layer comprises an ethylene polymer and a propylene polymer.

5. The laminated film according to claim 1 or 2, wherein the laminated film further comprises a pinhole-resistant layer containing polyamide.

6. The laminated film according to claim 1 or 2, wherein the laminated film further comprises an oxygen barrier layer containing an ethylene-vinyl alcohol copolymer.

7. A packaging body constructed using the laminated film described in claim 1 or 2.

8. The packaging comprises a lid and a bottom, The packaging is constructed by sealing the lid material and the bottom material, The packaging body according to claim 7, wherein the bottom material is a molded body of the laminated film.

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