JP7484084B2 - Multilayer film and packaging for meat packaging - Google Patents

Description

The present invention relates to a multilayer film and packaging body for packaging meat.

Conventionally, packaging bags for meat are known that use multi-layer films that have oxygen barrier properties and sealing properties. Such packaging bags are, for example, constructed with a base material and a lid material, and the base material has a recess formed therein to form a storage section for storing meat. Either the base material or the lid material, or both, are made of the multi-layer film.

When packaging meat, the meat is stored in the recess of the base material, and the surface of the base material on which the meat is exposed is then placed over the surface of the lid material. With the inside of the recess in a vacuum state, the peripheral edges of the base material and the lid material are heat sealed to form a storage section and the meat is hermetically sealed within the storage section. Either or both of the base material and the lid material are transparent, so the stored meat can be easily seen from outside the package (see Patent Documents 1 and 2).

In this way, in packaging bags containing meat, the base material and the lid material are sealed at the periphery, whereas the area closer to the storage section than this sealed area and not included in the storage section is usually not sealed or is only lightly sealed, with the base material and the lid material remaining in close contact due to the effect of reduced pressure caused by drawing a vacuum inside the storage section. In this specification, the area of the package where the base material and the lid material are in close contact like this is referred to as the "unsealed area," meaning that it is not completely sealed.

JP 2008-127035 A JP 2005-119282 A

Liquid may leak out of meat during storage. In this specification, liquid that leaks out of meat in this way is referred to as "drip." Unless special measures are taken, drip may also occur even when meat is stored in a package. Furthermore, in such cases, drip may accumulate in the unsealed areas of the package. When dripping occurs in this way, there is an appearance problem in that the appearance of the packaged meat becomes poor.

The objective of the present invention is to provide a package that can prevent dripping during storage of meat, and a film for manufacturing the package.

In order to solve the above problems, the present invention employs the following configuration.
[1] A multi-layer film for packaging meat, comprising a sealant layer and a protective layer, the protective layer containing nylon and the sealant layer containing an ionomer.
[2] The multi-layer film for packaging meat according to [1], wherein the metal ions constituting the ionomer are zinc ions or sodium ions.
[3] The multilayer film for packaging meat according to [1] or [2], wherein the ionomer is an ionomer of an ethylene-based copolymer.
[4] A packaging body comprising the multi-layer film for packaging meat according to any one of [1] to [3].
[5] The packaging body according to [4], wherein 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, and either or both of the lid material and the base material are made of the multi-layer film for packaging meat.

The present invention provides a package that can prevent dripping during storage of meat, and a film for producing the package.

1 is a cross-sectional view illustrating an example of a multilayer film according to an embodiment of the present invention. 1 is a cross-sectional view showing a schematic diagram of a package according to one embodiment of the present invention.

<<Multi-layer film for meat packaging>>
A multi-layer film for packaging meat according to one embodiment of the present invention comprises a sealant layer and a protective layer, the protective layer containing nylon and the sealant layer containing an ionomer.
The multilayer film for packaging meat of this embodiment has a sealant layer containing an ionomer, and therefore, in a package made of this multilayer film, the occurrence of dripping from the stored meat can be suppressed. In addition, the package has high self-weld property, in which the adhesion of the non-sealed area is stably maintained. Here, as explained above, the "non-sealed area" means an area in the package that is closer to the storage section than the sealed area and is not included in the storage section, and is an area that is usually not sealed or is lightly sealed, and is in a state where the base material and the lid material are in close contact with each other due to the effect of reduced pressure caused by vacuuming the storage section.
On the other hand, the multilayer film for packaging meat of the present embodiment has a protective layer containing nylon, which suppresses the occurrence of pinholes penetrating the multilayer film in the thickness direction, i.e., has high pinhole resistance, and therefore a package made of this multilayer film has a high meat packaging effect.

In this specification, the "multilayer film for packaging meat" of this embodiment may be simply referred to as the "multilayer film." In this specification, the term "multilayer film" refers to the "multilayer film for packaging meat" of this embodiment, unless otherwise specified.

The multilayer film of this embodiment is suitable as both a lid material and a base material for forming a package, as described below.

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 enlarged essential parts 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.

FIG. 1 is a cross-sectional view that illustrates an example of the multilayer film of the present embodiment.
The multilayer film 1 shown here comprises a sealant layer 11 and a protective layer 14 .
Furthermore, the multilayer film 1 includes an intermediate layer 12 and a first adhesive layer 131 in this order between the sealant layer 11 and the protective layer 14 in the direction from the sealant layer 11 to the protective layer 14, and includes an oxygen barrier layer 15, a second adhesive layer 132, and an outer layer 16 in this order on the protective layer 14 in the direction away from the sealant layer 11. That is, the multilayer film 1 includes the sealant layer 11, and is configured by laminating on the sealant layer 11 the intermediate layer 12, the first adhesive layer 131, the protective layer 14, the oxygen barrier layer 15, the second adhesive layer 132, and the outer layer 16 in this order in the thickness direction.
In this specification, a plurality of adhesive layers such as the first adhesive layer 131, the second adhesive layer 132, etc. may be collectively referred to simply as "adhesive layers."

<Sealant Layer>
The sealant layer 11 includes an ionomer.
The sealant layer 11 is one of the outermost layers of the multilayer film 1, and the exposed surface 11a (sometimes referred to as the "first surface" in this specification) of the sealant layer 11 opposite the intermediate layer 12 is one of the outermost surfaces of the multilayer film 1.
A first surface 11a of the sealant layer 11 is a sealing surface, and a part of the first surface 11a is overlapped with the surface of another film and sealed by heating to form a package. On the other hand, a part of the unsealed area forms a storage section for the target meat in the package and comes into contact with the meat.

By packaging meat in a packaging bag obtained using the multilayer film 1, the surface of the meat in the storage section comes into contact with the first surface 11a of the sealant layer 11. Therefore, the meat packaged in the packaging bag is stored with its surface in contact with the sealant layer 11 containing the ionomer. The occurrence of dripping is suppressed in meat stored in this manner.
Furthermore, in the non-sealed areas of the packaging bag after packaging the meat, the first surface 11a of the sealant layer 11 remains in close contact with the surface of another film or with the surface of a sealant layer similar to the sealant layer 11. In this way, by having one or both of the contact surfaces be the sealant layer (sealant layer 11) of this embodiment, the adhesion of the non-sealed areas is stably maintained. And by maintaining this adhesion, even if a small amount of drip occurs, the drip does not accumulate in the non-sealed areas, and the appearance of the packaged meat is maintained in a good state.

The sealant layer 11 may contain only an ionomer (i.e., it may consist of an ionomer), or it may contain an ionomer and other components (sometimes referred to as "other components" in this specification) (i.e., it may consist of an ionomer and the other components).

The ionomer is composed of a base resin and metal ions, and more specifically, has a crosslinked structure in which the acid portion (e.g., carboxyl group) in the base resin and the metal ion form a salt.

The base resin may be, for example, a copolymer having a structural unit derived from an olefin and a structural unit derived from an α,β-unsaturated carboxylic acid.
Examples of the olefin include ethylene, propylene, 1-butene, and styrene.
Examples of the α,β-unsaturated carboxylic acid include (meth)acrylic acid and maleic acid.
In this specification, the term "(meth)acrylic acid" is a concept that encompasses both "acrylic acid" and "methacrylic acid." The same applies to terms similar to (meth)acrylic acid.

The base resin constituting the ionomer may have structural units derived from olefins, structural units derived from α,β-unsaturated carboxylic acids, and other structural units that do not fall into any of these categories.

Examples of the other structural units include structural units derived from an α,β-unsaturated carboxylic acid ester and structural units derived from vinyl acetate.
Examples of the α,β-unsaturated carboxylic acid ester include (meth)acrylic acid ester and maleic acid ester.
Examples of the alcohol constituting the α,β-unsaturated carboxylic acid ester and maleic acid ester include linear or branched alcohols having 1 to 10 carbon atoms. More specific examples include methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol (sec-butyl alcohol), 2-methyl-1-propanol (isobutyl alcohol), 2-methyl-2-propanol (tert-butyl alcohol), 1-pentanol, 2-pentanol, 3-methyl-1-butanol (isoamyl alcohol), 2-methyl-2-butanol (tert-amyl alcohol), 2,2-dimethyl-1-propanol (neopentyl alcohol), 1-hexanol, 1-octanol, 2-ethylhexanol, and 1-decanol.

The structural units derived from the olefin, the structural units derived from the α,β-unsaturated carboxylic acid, and the other structural units contained in the base resin may each be of one type or of two or more types, and when there are two or more types, the combination and ratio of these can be selected arbitrarily.

Preferred examples of the base resin include copolymers having structural units derived from ethylene and structural units derived from a monomer other than ethylene (sometimes referred to as "ethylene-based copolymers" in this specification); and copolymers having structural units derived from styrene and structural units derived from a monomer other than styrene (sometimes referred to as "styrene-based copolymers" in this specification).

A preferred example of the ethylene-based copolymer is a copolymer having a structural unit derived from ethylene and a structural unit derived from (meth)acrylic acid (sometimes referred to in this specification as an "ethylene-(meth)acrylic acid copolymer-based resin").
A preferred example of the styrene-based copolymer is a copolymer having a structural unit derived from styrene and a structural unit derived from (meth)acrylic acid (sometimes referred to in this specification as a "styrene-(meth)acrylic acid copolymer-based resin").

Preferable examples of the ethylene-(meth)acrylic acid copolymer resin include an ethylene-(meth)acrylic acid copolymer that does not have the other structural units; an ethylene-(meth)acrylic acid-(meth)acrylic acid ester copolymer that has a (meth)acrylic acid ester as the other structural unit; and an ethylene-(meth)acrylic acid-maleic acid ester copolymer that has a maleic acid ester as the other structural unit.
Preferable examples of the styrene-(meth)acrylic acid copolymer resin include a styrene-(meth)acrylic acid copolymer that does not have the other structural units; a styrene-(meth)acrylic acid-(meth)acrylic acid ester copolymer that has a (meth)acrylic acid ester as the other structural unit; and a styrene-(meth)acrylic acid-maleic acid ester copolymer that has a maleic acid ester as the other structural unit.

The base resin is preferably an ethylene-based copolymer. In other words, the ionomer is preferably an ionomer of an ethylene-based copolymer.

Examples of the metal ions constituting the ionomer include monovalent ions such as sodium ion (Na ⁺ ), potassium ion (K ⁺ ), silver ion (Ag ⁺ ), and copper (I) ion (Cu ⁺ ); and divalent (polyvalent ions) such as barium ion (Ba ²⁺ ), zinc ion (Zn ²⁺ ), copper (II) ion (Cu ²⁺ ), and iron (II) ion (Fe ²⁺ ).

Among these, the metal ions constituting the ionomer are preferably zinc ions or sodium ions, and more preferably zinc ions.

The ionomer may contain only one type of metal ion or two or more types, and when there are two or more types, the combination and ratio of these can be selected arbitrarily.

More preferred examples of the ionomer include an ionomer containing an ethylene-(meth)acrylic acid copolymer and a sodium ion; an ionomer containing an ethylene-(meth)acrylic acid copolymer and a zinc ion; an ionomer containing an ethylene-(meth)acrylic acid-(meth)acrylic acid ester copolymer and a sodium ion; an ionomer containing an ethylene-(meth)acrylic acid-(meth)acrylic acid ester copolymer and a zinc ion; an ionomer containing an ethylene-(meth)acrylic acid-maleic acid ester copolymer and a sodium ion; an ionomer containing an ethylene-(meth)acrylic acid-maleic acid ester copolymer and a zinc ion. ionomers containing a styrene-(meth)acrylic acid copolymer and a sodium ion; ionomers containing a styrene-(meth)acrylic acid copolymer and a zinc ion; ionomers containing a styrene-(meth)acrylic acid-(meth)acrylic acid ester copolymer and a sodium ion; ionomers containing a styrene-(meth)acrylic acid-(meth)acrylic acid ester copolymer and a zinc ion; ionomers containing a styrene-(meth)acrylic acid-maleic acid ester copolymer and a sodium ion; ionomers containing a styrene-(meth)acrylic acid-maleic acid ester copolymer and a zinc ion, etc.

The ionomer is more preferably an ionomer of an ethylene-based copolymer in which the metal ion is a zinc ion or a sodium ion, and particularly preferably an ionomer of an ethylene-based copolymer in which the metal ion is a zinc ion.

The sealant layer 11 may contain only one type of ionomer, or two or more types. If there are two or more types, the combination and ratio of these can be selected arbitrarily.

The other components contained in the sealant layer 11 are not particularly limited and can be selected arbitrarily depending on the purpose, and may be, for example, either a resin component or a non-resin component.

The other component, which is a resin component, is a resin other than the ionomer.
Examples of the other components that are non-resin components include additives known in the art.
Examples of the additives include antioxidants, antistatic agents, crystal nucleating agents, inorganic particles, viscosity reducers, thickeners, heat stabilizers, lubricants, infrared absorbers, ultraviolet absorbers, and antifogging agents.

The sealant layer 11 may contain only one type of other component, or two or more types. If there are two or more types, the combination and ratio of these components can be selected arbitrarily.

The ratio of the ionomer content in the sealant layer 11 to the total mass of the sealant layer 11 is preferably 85% by mass or more, more preferably 90% by mass or more, and even more preferably 95% by mass or more, and may be, for example, any one of 97% by mass or more and 99% by mass or more. When the ratio is equal to or more than the lower limit, in a package formed using the multilayer film 1, both the effect of suppressing the generation of drips from the stored meat and the effect of stably maintaining the adhesion of the non-sealed portions are enhanced without impairing the seal strength of the sealant layer 11.
The upper limit of the ratio is not particularly limited. For example, the ratio may be 100% by mass or less.

In other words, the ratio of the content of the other components in the sealant layer 11 to the total mass of the sealant layer 11 is preferably 15 mass% or less, more preferably 10 mass% or less, and even more preferably 5 mass% or less, and may be, for example, any one of 3 mass% or less and 1 mass% or less. When the ratio is equal to or less than the upper limit, the above-mentioned effect is further enhanced.
The lower limit of the ratio is not particularly limited. For example, the ratio may be 0 mass % or more.

The sealant layer 11 may consist of one layer (single layer) or may consist of two or more layers. When the sealant layer 11 consists 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.

In this specification, not only in the case of the sealant layer 11, "multiple layers may be the same or different" means "all layers may be the same, all layers may be different, or only some layers may be the same," and further, "multiple layers are different" means "at least one of the constituent materials and thicknesses of each layer is different from each other."

The thickness of the sealant layer 11 is preferably 3 to 100 μm, more preferably 5 to 70 μm, and even more preferably 7 to 50 μm, and may be, for example, 10 to 40 μm, regardless of whether the multilayer film 1 is used as a lid material or a base material for a package described later. When the thickness of the sealant layer 11 is equal to or greater than the lower limit, the seal strength of the sealant layer 11 is increased. When the thickness of the sealant layer 11 is equal to or less than the upper limit, the sealant layer 11 is prevented from becoming excessively thick.
Here, "the thickness of the sealant layer 11" means the thickness of the entire sealant layer 11, and for example, the thickness of the sealant layer 11 consisting of multiple layers means the total thickness of all layers that make up the sealant layer 11.

<Protective Layer>
The protective layer 14 includes nylon.
The protective layer 14 imparts high puncture strength, pinhole resistance, and the like to the multilayer film 1 .

The protective layer 14 may contain only nylon (i.e., it may consist of nylon), or it may contain nylon and other components (sometimes referred to as "other components" in this specification) (i.e., it may consist of nylon and the other components).

Examples of the nylon include 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, and a copolymer of 6-nylon and 611-nylon. Examples of such copolymers include copolymers of nylon and 6T-nylon, copolymers of 6-nylon and 6I-nylon, copolymers of 6-nylon and 66-nylon to form 610-nylon, copolymers of 6-nylon and 66-nylon to form 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.
Among these, preferred nylons include nylon 6 and nylon 6/66.

The protective layer 14 may contain only one type of nylon or two or more types. If there are two or more types, the combination and ratio of the nylons can be selected arbitrarily.

The other components contained in the protective layer 14 are not particularly limited and can be selected arbitrarily depending on the purpose, and may be, for example, either a resin component or a non-resin component.

The other component, which is a resin component, is a resin other than nylon.
Examples of the other components that are non-resin components include additives known in the art.
Examples of the additives include the same additives as those that may be contained in the sealant layer 11 .

The protective layer 14 may contain only one type of other component, or two or more types. If there are two or more types, the combination and ratio of these components can be selected arbitrarily.

The proportion of nylon in the protective layer 14 relative to the total mass of the protective layer 14 is preferably 85% by mass or more, more preferably 90% by mass or more, and even more preferably 95% by mass or more, and may be, for example, any one of 97% by mass or more and 99% by mass or more. When the proportion is equal to or more than the lower limit, the pinhole resistance of a package formed using the multilayer film 1 is increased.
The upper limit of the ratio is not particularly limited. For example, the ratio may be 100% by mass or less.

In other words, the ratio of the content of the other components in the protective layer 14 to the total mass of the protective layer 14 is preferably 15% by mass or less, more preferably 10% by mass or less, and even more preferably 5% by mass or less, and may be, for example, any one of 3% by mass or less and 1% by mass or less. When the ratio is equal to or less than the upper limit, the above-mentioned effect is further enhanced.
The lower limit of the ratio is not particularly limited. For example, the ratio may be 0 mass % or more.

The protective layer 14 may consist of one layer (single layer) or may consist of two or more layers. When the protective layer 14 consists 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 thickness of the protective layer 14 is preferably 3 to 100 μm, more preferably 5 to 70 μm, and even more preferably 7 to 50 μm, and may be, for example, 10 to 40 μm, regardless of whether the multilayer film 1 is used as a lid material or a base material for a packaging body described below. When the thickness of the protective layer 14 is equal to or greater than the lower limit, the pinhole resistance of the multilayer film 1 is improved. When the thickness of the protective layer 14 is equal to or less than the upper limit, the protective layer 14 is prevented from becoming excessively thick.
Here, "the thickness of protective layer 14" means the thickness of the entire protective layer 14, and for example, the thickness of protective layer 14 consisting of multiple layers means the total thickness of all layers that make up protective layer 14.

<Middle class>
The intermediate layer 12 imparts a function to the multilayer film 1 in addition to the sealant layer 11 and the protective layer 14 .
In the multilayer film of the present embodiment, the intermediate layer may have any configuration, and the multilayer film may or may not have an intermediate layer, but it is preferable that the multilayer film has an intermediate layer in that the multilayer film has higher functionality.

An example of the intermediate layer 12 is a layer that increases the overall thickness of the multilayer film 1 to a certain value or greater, thereby improving the strength or handleability of the multilayer film 1 .
Examples of layers that increase the thickness include layers containing resins such as ethylene-(meth)acrylic acid copolymer (EMAA), ethylene-based ionomer, low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), high-density polyethylene (HDPE), and ethylene-vinyl acetate copolymer (EVA).

The intermediate layer 12 (layer that increases the thickness) may contain only the resin (i.e., it may consist of the resin), or it may contain the resin and other components (sometimes referred to as "other components" in this specification) (i.e., it may consist of the resin and the other components).

The intermediate layer 12 may contain only one type of resin, or two or more types. If there are two or more types, the combination and ratio of the resins can be selected as desired depending on the purpose.

The other components contained in the intermediate layer 12 are not particularly limited and can be arbitrarily selected depending on the purpose.
Examples of the other components include additives known in the art that are non-resin components, and examples of the additives include the same additives that the sealant layer 11 may contain.

The intermediate layer 12 may contain only one type of other component, or two or more types. If there are two or more types, the combination and ratio of these components can be selected arbitrarily.

The ratio of the content of the resin in the intermediate layer 12 to the total mass of the intermediate layer 12 is preferably 85 mass% or more, more preferably 90 mass% or more, and even more preferably 95 mass% or more, and may be, for example, any one of 97 mass% or more and 99 mass% or more. When the ratio is equal to or more than the lower limit, the effect of providing the intermediate layer 12 in the multilayer film 1 is enhanced.
The upper limit of the ratio is not particularly limited. For example, the ratio may be 100% by mass or less.

In other words, the ratio of the content of the other components in the intermediate layer 12 to the total mass of the intermediate layer 12 is preferably 15 mass% or less, more preferably 10 mass% or less, and even more preferably 5 mass% or less, and may be, for example, any one of 3 mass% or less and 1 mass% or less. When the ratio is equal to or less than the upper limit, the above-mentioned effect is further enhanced.
The lower limit of the ratio is not particularly limited. For example, the ratio may be 0 mass % or more.

The intermediate layer 12 may be made up of one layer (single layer) or two or more layers. When the intermediate layer 12 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 thickness of the intermediate layer 12 is preferably 5 to 120 μm, more preferably 10 to 100 μm, and even more preferably 15 to 80 μm, and may be, for example, 15 to 65 μm, regardless of whether the multilayer film 1 is used as a lid material or a base material for a package described later. When the thickness of the intermediate layer 12 is equal to or greater than the lower limit, the effect obtained by providing the intermediate layer 12 is enhanced. When the thickness of the intermediate layer 12 is equal to or less than the upper limit, the intermediate layer 12 is prevented from becoming excessively thick.
Here, "the thickness of intermediate layer 12" means the thickness of the entire intermediate layer 12, and for example, the thickness of intermediate layer 12 consisting of multiple layers means the total thickness of all layers that make up intermediate layer 12.

<Oxygen Barrier Layer>
The oxygen barrier layer 15 imparts strong oxygen barrier properties (in other words, the property of suppressing the permeation of oxygen gas) to the multilayer film 1 .
In the multilayer film of the present embodiment, the oxygen barrier layer may have any configuration, and the multilayer film may or may not have an oxygen barrier layer. However, it is preferable that the multilayer film has an oxygen barrier layer in that the oxygen barrier properties are significantly improved.

The resin component contained in the oxygen barrier layer 15 may be, for example, an oxygen barrier resin such as saponified ethylene-vinyl acetate copolymer (sometimes abbreviated as "EVOH" in this specification).

The oxygen barrier layer 15 may contain only an oxygen barrier resin (i.e., it may consist of an oxygen barrier resin), or it may contain an oxygen barrier resin and other components (sometimes referred to as "other components" in this specification) (i.e., it may consist of an oxygen barrier resin and the other components).

The oxygen barrier layer 15 may contain only one type of oxygen barrier resin, or two or more types. If there are two or more types, the combination and ratio of the resins can be selected as desired depending on the purpose.

The other components contained in the oxygen barrier layer 15 are not particularly limited and can be selected arbitrarily depending on the purpose, and may be, for example, either a resin component or a non-resin component.

The other component, which is a resin component, is a resin other than the oxygen barrier resin.
Examples of the other components that are non-resin components include additives known in the art.
Examples of the additives include the same additives as those that may be contained in the sealant layer 11 .

The oxygen barrier layer 15 may contain only one type of other component, or two or more types. If there are two or more types, the combination and ratio of these components can be selected arbitrarily.

The ratio of the content of the oxygen barrier resin in the oxygen barrier layer 15 to the total mass of the oxygen barrier layer 15 is preferably 85 mass% or more, more preferably 90 mass% or more, and even more preferably 95 mass% or more, and may be, for example, any one of 97 mass% or more and 99 mass% or more. When the ratio is equal to or more than the lower limit, the oxygen barrier property of the package formed using the multilayer film 1 is improved.
The upper limit of the ratio is not particularly limited. For example, the ratio may be 100% by mass or less.

In other words, the ratio of the content of the other components in the oxygen barrier layer 15 to the total mass of the oxygen barrier layer 15 is preferably 15 mass% or less, more preferably 10 mass% or less, and further preferably 5 mass% or less, and may be, for example, any one of 3 mass% or less and 1 mass% or less. When the ratio is equal to or less than the upper limit, the above-mentioned effect is further enhanced.
The lower limit of the ratio is not particularly limited. For example, the ratio may be 0 mass % or more.

The oxygen barrier layer 15 may consist of one layer (single layer) or may consist of two or more layers. When the oxygen barrier layer 15 consists 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 thickness of the oxygen barrier layer 15 is preferably 2 to 20 μm, more preferably 3 to 16 μm, and even more preferably 3 to 12 μm, and may be, for example, 3 to 10 μm, regardless of whether the multilayer film 1 is used as a lid material or a base material of a package described later. When the thickness of the oxygen barrier layer 15 is equal to or greater than the lower limit, the oxygen barrier property of the multilayer film 1 is improved. When the thickness of the oxygen barrier layer 15 is equal to or less than the upper limit, the oxygen barrier layer 15 is prevented from becoming excessively thick.
Here, the "thickness of the oxygen barrier layer 15" means the thickness of the entire oxygen barrier layer 15. For example, the thickness of the oxygen barrier layer 15 consisting of multiple layers means the total thickness of all layers constituting the oxygen barrier layer 15.

<Outer layer>
The outer layer 16 is the other outermost layer of the multilayer film 1, and the exposed surface 16b of the outer layer 16 opposite the second adhesive layer 132 (sometimes referred to as the "second surface" in this specification) is the other outermost surface of the multilayer film 1.
In the multilayer film of this embodiment, the outer layer may be of any configuration, and the multilayer film may or may not have an outer layer, but it is preferable that the multilayer film has an outer layer in terms of improving the strength of the multilayer film.

The outer layer 16 is, for example, a layer that provides the multilayer film 1 with adequate strength and pinhole resistance, and preferably contains nylon.

The nylon-containing outer layer 16 may be similar to the protective layer 14 described above, except for thickness.

The thickness of the outer layer 16 is preferably 2 to 20 μm, more preferably 3 to 16 μm, and even more preferably 3 to 12 μm, regardless of whether the multilayer film 1 is used as a lid material or a base material of a package described below. When the thickness of the outer layer 16 is equal to or greater than the lower limit, the effect of providing the outer layer 16 is enhanced. When the thickness of the outer layer 16 is equal to or less than the upper limit, the outer layer 16 is prevented from becoming excessively thick.
Here, the "thickness of the outer layer 16" means the thickness of the entire outer layer 16, and for example, the thickness of the outer layer 16 consisting of multiple layers means the total thickness of all layers that make up the outer layer 16.

<Adhesive Layer (First Adhesive Layer, Second Adhesive Layer)>
The first adhesive layer 131 and the second adhesive layer 132 each contain an adhesive and bond two adjacent layers on both sides of the first adhesive layer 131. More specifically, the first adhesive layer 131 bonds the intermediate layer 12 and the protective layer 14, and the second adhesive layer 132 bonds the oxygen barrier layer 15 and the outer layer 16.
In the multilayer film of this embodiment, the adhesive layer may be of any configuration, and the multilayer film may or may not have an adhesive layer, but it is preferable that the multilayer film has an adhesive layer in that the structure of the multilayer film is more stable.

The first adhesive layer 131 and the second adhesive layer 132 may be the same as each other or different.

The adhesive contained in the first adhesive layer 131 and the second adhesive layer 132 is not particularly limited as long as it can bond the two layers to be bonded together with sufficient strength.
The adhesive may be, for example, an adhesive resin such as an olefin-based resin (that is, a polymer of one or more types of olefin monomers).

More specifically, the olefin-based resin may be, for example, an ethylene-based copolymer, a propylene-based copolymer, or a butene-based copolymer, and may be a polyolefin having a polar group.
The ethylene-based copolymer is a copolymer of ethylene and a monomer other than ethylene.
The propylene-based copolymer is a copolymer of propylene and a monomer other than propylene.
The butene copolymer is a copolymer of butene and a monomer other than butene.

The ethylene copolymer may, for example, be a copolymer of ethylene and a vinyl group-containing monomer.
Examples of copolymers of ethylene and vinyl group-containing monomers include maleic anhydride-grafted linear low density polyethylene (sometimes abbreviated herein as "LLDPE-g-MAH"), ethylene-vinyl acetate copolymer (sometimes abbreviated herein as "EVA"), ethylene-methyl methacrylate copolymer (sometimes abbreviated herein as "EMMA"), ethylene-ethyl acrylate copolymer (sometimes abbreviated herein as "EEA"), ethylene-methyl acrylate copolymer (sometimes abbreviated herein as "EMA"), ethylene-ethyl acrylate-maleic anhydride copolymer (sometimes abbreviated herein as "E-EA-MAH"), ethylene-acrylic acid copolymer (sometimes abbreviated herein as "EAA"), ethylene-methacrylic acid copolymer (sometimes abbreviated herein as "EMAA"), ionomers, ethylene-based thermoplastic elastomers, and the like.
The ionomer contained in the first adhesive layer 131 and the second adhesive layer 132 may be, for example, a copolymer of ethylene and a small amount of acrylic acid or methacrylic acid, which has an ionic cross-linked structure due to salt formation between the acid portion and metal ions.

The first adhesive layer 131 and the second adhesive layer 132 may each contain only adhesive (i.e., may consist of adhesive), or may contain adhesive and other components (sometimes referred to as "other components" in this specification) (i.e., may consist of adhesive and the other components).

The adhesive contained in the first adhesive layer 131 and the second adhesive layer 132 may each be only one type or two or more types. If there are two or more types, the combination and ratio of the adhesives can be selected arbitrarily according to the purpose.

The other components contained in the first adhesive layer 131 and the second adhesive layer 132 are not particularly limited and can be selected arbitrarily depending on the purpose, and may be, for example, either a resin component or a non-resin component.

The other components contained in the first adhesive layer 131 and the second adhesive layer 132 may each be only one type or two or more types. If there are two or more types, the combination and ratio of these can be selected arbitrarily depending on the purpose.

The content of the adhesive in the first adhesive layer 131 relative to the total mass of the first adhesive layer 131 may be, for example, 85 to 100 mass %.
In other words, the content ratio of the other components in the first adhesive layer 131 with respect to the total mass of the first adhesive layer 131 may be 0 to 15 mass %.
The content ratio of these adhesives and the content ratio of the other components are similar to those in the second adhesive layer 132 .

The first adhesive layer 131 and the second adhesive layer 132 may each be made up of one layer (single layer) or two or more layers. When the first adhesive layer 131 or the second adhesive layer 132 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.

Regardless of whether the multilayer film 1 is for use as a lid material or a base material of a package described below, the thicknesses of the first adhesive layer 131 and the second adhesive layer 132 are preferably 2 to 20 μm, more preferably 3 to 17 μm, and even more preferably 4 to 14 μm. When the thicknesses of the adhesive layer 131 and the second adhesive layer 132 are equal to or greater than the lower limit, the adhesive strength of the two layers to be bonded is increased. When the thicknesses of the adhesive layer 131 and the second adhesive layer 132 are equal to or less than the upper limit, the adhesive layer 131 and the second adhesive layer 132 are prevented from becoming excessively thick.
Here, "the thickness of the first adhesive layer 131" means the thickness of the entire first adhesive layer 131, and for example, the thickness of the first adhesive layer 131 consisting of multiple layers means the total thickness of all layers that make up the first adhesive layer 131.
The "thickness of the second adhesive layer 132" is the same as above.

<Other layers>
The multilayer film 1 may have other layers that do not fall into any of the following categories: sealant layer 11, intermediate layer 12, first adhesive layer 131, protective layer 14, oxygen barrier layer 15, second adhesive layer 132, and outer layer 16, as long as the effects of the present invention are not impaired.
The other layer is not particularly limited and can be arbitrarily selected depending on the purpose.
When the multilayer film 1 has the other layers, it may further have an adhesive layer (e.g., a layer similar to the first adhesive layer 131 or the second adhesive layer 132) for adhering the other layers to other layers.

The multilayer film of the present embodiment is not limited to the above, and some of the configuration may be changed, deleted, or added without departing from the spirit of the present invention.
For example, in the multilayer film 1 shown in FIG. 1, the intermediate layer 12, the protective layer 14, and the oxygen barrier layer 15 are laminated in this order from the sealant layer 11 side to the outer layer 16 side, but the lamination order of these layers may be other than the above, such as the reverse.

The thickness of the multilayer film 1 can be arbitrarily selected depending on the purpose and is not particularly limited.
For example, regardless of whether the multilayer film 1 is for a cover material or a base material of a package described below, the thickness of the multilayer film 1 may be 40 to 230 μm.

The thickness of the multilayer film 1 for the base material is preferably 100 to 230 μm, more preferably 115 to 200 μm, and even more preferably 130 to 170 μm. When the thickness of the multilayer film 1 for the base material is equal to or greater than the lower limit, the rigidity of the package is increased. When the thickness of the multilayer film 1 for the base material is equal to or less than the upper limit, the package is prevented from becoming excessively thick.

The thickness of the lid material multilayer film 1 is preferably 40 to 140 μm, more preferably 55 to 125 μm, and even more preferably 70 to 110 μm. When the thickness of the lid material multilayer film 1 is equal to or greater than the lower limit, the rigidity of the package is increased. When the thickness of the lid material multilayer film 1 is equal to or less than the upper limit, the package is prevented from becoming excessively thick.
The packaging will be described in more detail later.

The multilayer film 1 is preferably transparent. A package using the transparent multilayer film 1 as either or both of the lid material and base material is useful in that the packaged object (content) can be easily seen from outside the package.

<<Method of manufacturing multilayer film>>
The multilayer film of the present embodiment 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.

The multilayer film of this embodiment can also be produced by coating the surface of another layer that constitutes the multilayer film with a resin or resin composition that will form one of the layers, and drying it as necessary to form a laminated structure in the multilayer film, and then further laminating other layers as necessary to obtain the desired arrangement.

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

The multilayer film of this embodiment 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.

When producing the multilayer film of this embodiment, two or more of the methods for forming any of the layers (films) in the multilayer film described above may be combined.

<<Packaging>>
A packaging body according to one embodiment of the present invention includes the multi-layer film for packaging meat according to one embodiment of the present invention described above.
The packaging body of this embodiment is provided with the multilayer film, and thus can suppress dripping from meat during packaging and storage. The packaging body of this embodiment also has high self-welding properties, which means that the adhesion of the non-sealed areas is stably maintained. The packaging body of this embodiment also has high pinhole resistance. Therefore, the packaging body of this embodiment is highly effective for packaging meat.

FIG. 2 is a cross-sectional view that illustrates a package according to one embodiment of the present invention.
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.

The packaging body 101 shown here is configured with a cover material 3 and a base material 2 .
The lid material 3 is in a sheet form, and is usually preferably transparent.
The base material 2 has a recess 20 formed therein. The base material 2 is obtained by deep drawing a film, and is usually preferably transparent.
Since either or both of the lid material 3 and the base material 2 are transparent, the contents 9 packaged in the package 101 can be easily viewed from outside the package 101.

In the packaging body 101, one side 2a of the area of the base material 2 excluding the recess 20 (sometimes referred to as the "first side" in this specification) and one side 3a of the lid material 3 (sometimes referred to as the "first side" in this specification) are both sealing surfaces and face each other. The first side 2a of the base material 2 is the side from which the stored item 9 is exposed when the stored item 9 is stored in the recess 20 without constituting the packaging body 101.

Furthermore, the package 101 is formed by sealing the lid material 3 and the base material 2. More specifically, the first surface 2a of the base material 2 except for the recessed portion 20 and the first surface 3a of the lid material 3 are overlapped and sealed to each other at their periphery, so that a storage section 101a is formed between the first surface 2a of the base material 2 and the first surface 3a of the lid material 3 in the region of the recessed portion 20 of the base material 2. The item 9 is stored in this storage section 101a. Meat is a suitable item 9.

The peripheral edge of the packaging body 101 is a sealed region 1011. The region of the packaging body 101 that is closer to the storage section 101a than the sealed region 1011 and that is not included in the storage section 101a is a non-sealed region 1012. In the non-sealed region 1012, the base material 2 and the lid material 3 are not sealed or are only lightly sealed, and are in close contact with each other due to the effect of reduced pressure caused by drawing a vacuum inside the storage section 101a during packaging.
When the packaging body 101 is viewed in a plan view looking down from above the lid material 3 side or from above the base material 2 side, in the packaging body 101, the non-sealed portion 1012 exists so as to surround the storage section 101a, and the sealed portion 1011 exists so as to surround the non-sealed portion 1012.

In the packaging body 101, either or both of the lid material 3 and the base material 2 are made of the multi-layer film for packaging meat according to one embodiment of the present invention. As the multi-layer film, for example, the multi-layer film 1 shown in Fig. 1 can be used, but is not limited thereto.
In FIG. 2, when either or both of the cover material 3 and the base material 2 are the multilayer film, the distinction between the layers in the multilayer film is omitted.

For example, when the lid material 3 is made of a multilayer film 1, the first surface 3a of the lid material 3 corresponds to the first surface 11a of the sealant layer 11 in the multilayer film 1, and the surface 3b opposite the first surface 3a of the lid material 3 (sometimes referred to as the "second surface" in this specification) corresponds to the second surface 16b of the outer layer 16 in the multilayer film 1.
Similarly, when the base material 2 is made of a multilayer film 1, the first surface 2a of the base material 2 corresponds to the first surface 11a of the sealant layer 11 in the multilayer film 1, and the surface 2b opposite the first surface 2a of the base material 2 (sometimes referred to as the "second surface" in this specification) corresponds to the second surface 16b of the outer layer 16 in the multilayer film 1.

By using the package 101 in which either or both of the lid material 3 and the base material 2 are the multilayer film, when the stored item 9 is meat, the occurrence of dripping from the stored item (meat) 9 during storage in the storage section 101a is suppressed. Furthermore, in the package 101, the adhesion of the non-sealed area 1012 is stably maintained. Furthermore, the area of the package 101 that is made of the multilayer film has high pinhole resistance.
In order to enhance these effects, it is preferable that in the packaging body 101, both the cover material 3 and the base material 2 are made of the multi-layer film for packaging meat according to one embodiment of the present invention.

In the package 101, typically, the lid material 3 and the stored item 9 are in direct contact. The area of the recess 20 of the base material 2, particularly the area of the bottom of the recess 20 (e.g., the area of the recess 20 facing the lid material 3), is in direct contact with the stored item 9. In Fig. 2, in the area of the recess 20 of the base material 2, the side portion and the stored item 9 are not in direct contact and a gap is seen, but they may be in direct contact.
In other words, the stored item 9 is in direct contact with the sealant layer containing an ionomer, and it is presumed that the action of this ionomer suppresses the generation of drips from the stored item (meat) 9 during storage in the storage section 101a when the stored item 9 is meat.

In addition, in the non-sealed area 1012 of the package 101, the base material 2 and the lid material 3 are in close contact with each other, and one or both of the contact surfaces contain an ionomer. It is presumed that the action of this ionomer keeps the adhesion of the non-sealed area 1012 stable.

In the case where the lid material 3 of the packaging body 101 is not made of the multi-layer film for packaging meat according to one embodiment of the present invention, the lid material 3 may be any material that can be used for ordinary deep-draw packaging bags. Examples of such lid materials 3 include those made of single-layer or multi-layer resin films.
In the case where the base material 2 of the package 101 is not made of the multi-layer film for packaging meat according to one embodiment of the present invention, the base material 2 may be any material that can be used in a normal deep-draw packaging bag. Examples of such a base material 2 include a single-layer or multi-layer resin film that has been deep-draw molded.

In the packaging body 101, when the lid material 3 or the base material 2 is made of the multilayer film for packaging meat according to one embodiment of the present invention described above, the thickness of the lid material 3 or the base material 2 is the same as the thickness of the multilayer film described above.
In the packaging body 101, when the lid material 3 and the base material 2 are both made of the multilayer film, it is preferable that the thicknesses of the lid material 3 and the base material 2 are within the numerical range of the thickness of the multilayer film described above, and that the thickness of the lid material 3 is thinner than the thickness of the base material 2.
When the cover material 3 or the base material 2 is made of a film other than the multilayer film, the thickness of the cover material 3 or the base material 2 may be the same as the thickness of the multilayer film.

The packaging of this embodiment is not limited to the above, and some of the configuration may be changed, deleted, or added without departing from the spirit of the present invention.

<<Manufacturing method of packaging body>>
The packaging body of this embodiment can be manufactured by overlapping the lid material and the base material so as to form the storage section, and heat sealing them.
In manufacturing the package, an item is placed in the storage section before the lid and base are heat-sealed together, and the lid and base are heat-sealed together while the storage section is in a vacuum state.

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

<<Manufacture of multilayer films and packaging bodies>>
[Example 1]
A multilayer film having the structure shown in FIG. 1 and a package having the structure shown in FIG. 2 were produced according to the procedure described below.

<Production of multi-layer film for base material>
As the resin constituting the sealant layer, an ionomer ("Himilan 1855" manufactured by DuPont-Mitsui Polychemicals) having an ethylene-(meth)acrylic acid copolymer (EMAA) as the base resin and zinc ions (Zn ²⁺ ) as the metal ions was prepared.
As a resin for forming the intermediate layer, an ethylene-(meth)acrylic acid copolymer ("Nucrel AN4901-1C" manufactured by DuPont-Mitsui Polychemicals) was prepared.
An acid-modified polyethylene composition ("Admer NF536" manufactured by Mitsui Chemicals, Inc.) was prepared as an adhesive resin constituting the first adhesive layer and the second adhesive layer.
As a resin for forming the protective layer and the outer layer, 6-nylon ("UBE nylon 1030B2" manufactured by Ube Industries, Ltd.) was prepared.
As a resin constituting the oxygen barrier layer, a saponified ethylene-vinyl acetate copolymer ("EVAL J171B" manufactured by Kuraray Co., Ltd.) was prepared.

Next, the sealant layer, the intermediate layer, the first adhesive layer, the protective layer, the oxygen barrier layer, the second adhesive layer and the outer layer were co-extruded in this order to produce a multi-layer film for base materials.
The resulting multilayer film had a thickness of 150 μm and was composed of a sealant layer (thickness 30 μm), an intermediate layer (thickness 49.5 μm), a first adhesive layer (thickness 10.5 μm), a protective layer (thickness 30 μm), an oxygen barrier layer (thickness 7.5 μm), a second adhesive layer (thickness 12 μm) and an outer layer (thickness 10.5 μm) laminated in the thickness direction in this order.

<Production of multi-layer film for covering material>
A multi-layer film for a cover material was produced in the same manner as in the production of the multi-layer film for a base material, except that the amount of resin used to constitute each layer was changed.
The resulting multilayer film had a thickness of 90 μm and was composed of a sealant layer (thickness 18 μm), an intermediate layer (thickness 29.7 μm), a first adhesive layer (thickness 6.3 μm), a protective layer (thickness 18 μm), an oxygen barrier layer (thickness 4.5 μm), a second adhesive layer (thickness 7.2 μm) and an outer layer (thickness 6.3 μm) laminated in the thickness direction in this order.

<Manufacturing of packaging body>
The multilayer film for base material obtained above was deep-drawn to produce a base material. The outer shape of the recess in the base material, which would become the storage section, was a square prism with dimensions of 15 cm x 11 cm x 2.5 cm.
Next, raw horse meat, one size smaller than the recess, was placed in the recess in the base material obtained above. In this state, the surface of the base material on which the meat was exposed (i.e., the first surface) was placed over the surface of the lid material (i.e., the first surface), and while drawing a vacuum inside the recess, the peripheries of the base material and the lid material were heat-sealed at 115°C to form a storage section and to seal the meat inside the storage section. At this time, the area between the heat-sealed periphery and the storage section was left as a non-sealed area.
In this manner, a package having meat stored in the storage section was manufactured.

[Example 2]
<Production of multi-layer film for base material>
A multilayer film for base material was manufactured in the same manner as in Example 1, except that an ionomer having an ethylene-methacrylic acid copolymer (EMAA) base resin and a sodium ion (Na ⁺ ) metal ion ("Himilan 1707" manufactured by DuPont-Mitsui Polychemicals) was used as the resin constituting the sealant layer, instead of an ionomer having an ethylene-methacrylic acid copolymer (EMAA) base resin and a zinc ion (Zn2 ⁺ ) metal ion.
The resulting multilayer film had a thickness of 150 μm and was composed of a sealant layer (thickness 30 μm), an intermediate layer (thickness 49.5 μm), a first adhesive layer (thickness 10.5 μm), a protective layer (thickness 30 μm), an oxygen barrier layer (thickness 7.5 μm), a second adhesive layer (thickness 12 μm) and an outer layer (thickness 10.5 μm) laminated in the thickness direction in this order.

<Production of multi-layer film for covering material>
A multilayer film for lid material was manufactured in the same manner as in Example 1, except that an ionomer having an ethylene-methacrylic acid copolymer (EMAA) base resin and a sodium ion (Na ⁺ ) metal ion ("Himilan 1707" manufactured by DuPont-Mitsui Polychemicals) was used as the resin constituting the sealant layer instead of an ionomer having an ethylene-methacrylic acid copolymer (EMAA) base resin and a zinc ion (Zn2 ⁺ ) metal ion.
The resulting multilayer film had a thickness of 90 μm and was composed of a sealant layer (thickness 18 μm), an intermediate layer (thickness 29.7 μm), a first adhesive layer (thickness 6.3 μm), a protective layer (thickness 18 μm), an oxygen barrier layer (thickness 4.5 μm), a second adhesive layer (thickness 7.2 μm) and an outer layer (thickness 6.3 μm) laminated in the thickness direction in this order.

<Manufacturing of packaging body>
A package was produced in the same manner as in Example 1, except that the base material multi-layer film and the cover material multi-layer film obtained above were used.

[Comparative Example 1]
<Production of multi-layer film for base material>
A multilayer film for base material was manufactured in the same manner as in Example 1, except that the base resin constituting the sealant layer was ethylene- ^methacrylic acid copolymer (EMAA), and linear low-density polyethylene (LLDPE) ("Yumerit 1520F" manufactured by Ube Maruzen Polyethylene Co., Ltd.) was used instead of an ionomer in which the metal ion was zinc ion (Zn 2+ ).
The resulting multilayer film had a thickness of 150 μm and was composed of a sealant layer (thickness 30 μm), an intermediate layer (thickness 49.5 μm), a first adhesive layer (thickness 10.5 μm), a protective layer (thickness 30 μm), an oxygen barrier layer (thickness 7.5 μm), a second adhesive layer (thickness 12 μm) and an outer layer (thickness 10.5 μm) laminated in the thickness direction in this order.

<Production of multi-layer film for covering material>
A multilayer film for a lid material was produced in the same manner as in Example 1, except that the base resin constituting the sealant layer was ethylene- ^methacrylic acid copolymer (EMAA), and linear low-density polyethylene (LLDPE) ("Yumerit 1520F" manufactured by Ube Maruzen Polyethylene Co., Ltd.) was used instead of an ionomer in which the metal ion was zinc ion (Zn 2+ ).
The resulting multilayer film had a thickness of 90 μm and was composed of a sealant layer (thickness 18 μm), an intermediate layer (thickness 29.7 μm), a first adhesive layer (thickness 6.3 μm), a protective layer (thickness 18 μm), an oxygen barrier layer (thickness 4.5 μm), a second adhesive layer (thickness 7.2 μm) and an outer layer (thickness 6.3 μm) laminated in the thickness direction in this order.

<Manufacturing of packaging body>
A package was produced in the same manner as in Example 1, except that the base material multi-layer film and the cover material multi-layer film obtained above were used.

<<Evaluation of packaging>>
<Evaluation of drip suppression effect>
The package containing the meat obtained above was stored at 20° C. for 48 hours.
The package after storage was then visually observed and the degree of dripping from the meat was evaluated according to the following criteria. The results are shown in Table 1.
(Evaluation criteria)
A: Almost no or no dripping was observed.
B: A small amount of dripping is observed, but the appearance of the packaged meat is not affected.
C: A large amount of dripping is observed, spoiling the appearance of the packaged meat.

<Evaluation of adhesion of unsealed parts in packaging>
At the same time as the above-mentioned "evaluation of the dripping suppression effect," the adhesion of the non-sealed portions of the package was visually observed and evaluated according to the following criteria. The results are shown in Table 1.
(Evaluation criteria)
A: The non-sealed area is kept tightly attached.
B: Peeling was observed in a very small part of the non-sealed area, but little or no dripping was observed in the peeled area.
C: Peeling was clearly observed in the non-sealed area, and drip accumulation was clearly observed in the peeled area.

<Evaluation of the effect of suppressing the occurrence of pinholes in packaging>
At the same time as the above-mentioned "evaluation of the effect of suppressing the occurrence of dripping," the effect of suppressing the occurrence of pinholes in the package was evaluated by visual observation according to the following criteria. The results are shown in Table 1.
(Evaluation criteria)
A: No pinholes are observed.
B: One or more pinholes are found.

As is clear from the above results, the packages of Examples 1 and 2 were good in the evaluation results for both the effect of suppressing drip generation and the adhesion of the non-sealed parts in the package, and in particular the package of Example 1 had better evaluation results than the package of Example 2. In both Examples 1 and 2, the sealant layer of the base material multilayer film and the sealant layer of the cover material multilayer film were both made of ionomer, but the ionomer in Example 1 was an ionomer whose base resin was EMAA and whose metal ion was Zn2 ⁺ .

In contrast, the package of Comparative Example 1 was evaluated as being inferior in both drip suppression effect and adhesion of the non-sealed portion of the package. In Comparative Example 1, neither the sealant layer of the base material multilayer film nor the sealant layer of the lid material multilayer film contained an ionomer.

On the other hand, the packages of Examples 1 and 2 and Comparative Example 1 were effective in suppressing the occurrence of pinholes. In these Examples and Comparative Example, the protective layer contained nylon.

The present invention can be used for packaging used to preserve meat.

REFERENCE SIGNS LIST 1: Multilayer film for packaging meat 11: Sealant layer 12: Intermediate layer 131: First adhesive layer 14: Protective layer 15: Oxygen barrier layer 132: Second adhesive layer 16: Outer layer 101: Package 2: Base material 3: Lid material 1011: Sealed portion of package 1012: Non-sealed portion of package 101a: Storage portion of package 9: Stored item (meat)
20: Recess of base material

Claims (6)

A multi-layer film for packaging meat comprising a sealant layer and a protective layer,
The multi-layer film for packaging meat further comprises an oxygen barrier layer and an outer layer, in this order, on the protective layer in a direction away from the sealant layer, and an intermediate layer directly laminated on a surface of the sealant layer facing the protective layer,
the protective layer comprises nylon;
the sealant layer comprises an ionomer;
the oxygen barrier layer comprises a saponified ethylene-vinyl acetate copolymer,
the outer layer comprises nylon;
the intermediate layer comprises an ethylene-(meth)acrylic acid copolymer ,
A multi-layer film for packaging meat, wherein the content of the ethylene-(meth)acrylic acid copolymer in the intermediate layer is 85% by mass or more relative to the total mass of the intermediate layer. The multilayer film for packaging meat according to claim 1, wherein the thickness of the intermediate layer is 15 to 80 μm. The multilayer film for packaging meat according to claim 1 or 2, wherein the metal ions constituting the ionomer are zinc ions or sodium ions. The multilayer film for packaging meat according to any one of claims 1 to 3, wherein the ionomer is an ionomer of an ethylene-based copolymer. A packaging body comprising the multilayer film for packaging meat according to any one of claims 1 to 4. 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,
6. The packaging body according to claim 5, wherein either or both of the lid material and the base material are made of the multi-layer film for packaging meat.

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