JP2021133679A - Transparent multilayer film and package - Google Patents

Abstract

To provide a transparent multilayer film without any slack or winding slip even after absorption of moisture.SOLUTION: A transparent multilayer film at least includes an easy peel layer and an outermost surface layer on an opposite side of the easy peel layer. A dynamic friction coefficient between the easy peel layer and the outermost surface layer is 0.10 or more and less than 1.0. A reduction rate of a tensile elastic modulus of the outermost surface layer is 20% or more after the outermost surface layer absorbed moisture under a condition of a temperature 20°C and a humidity 90%, and the thickness of the outermost surface layer is 20 μm or less.SELECTED DRAWING: Figure 1

Description

The present invention relates to transparent multilayer films and packages.

Among food packaging, packaging used for cooking in a microwave oven includes, for example, a tray sealed with a lid (a packaging having a tray) and deep drawing. It is known that the bottom material is sealed with a lid material (deeply squeezed package). As the tray, bottom material and lid material, those made of resin can be used.

Among food packages, those having a transparent lid material are in great demand because the packaged food can be visually recognized from the outside of the package through the lid material.
On the other hand, the film constituting the lid material is required to have an easy peel property for the tray or the bottom material, a barrier property for suppressing the permeation of oxygen and water vapor, a pinhole resistance, and the like.
Therefore, a transparent multilayer film is usually used as the film constituting the lid material (see Patent Document 1).

Japanese Unexamined Patent Publication No. 2005-288793

However, the conventional transparent multilayer film has a problem that tarmi and winding misalignment are likely to occur during storage because the tensile elastic modulus is greatly reduced due to moisture absorption especially in summer. On the other hand, it is uncertain whether or not the transparent multilayer film described in Patent Document 1 solves such a problem.

An object of the present invention is to provide a transparent multilayer film that does not cause tarmi or winding misalignment even when it absorbs moisture.

In order to solve the above problems, the present invention adopts the following configuration.
[1]. A transparent multilayer film comprising at least an easy peel layer and an outermost layer on the opposite side of the easy peel layer, wherein the dynamic friction coefficient between the easy peel layer and the outermost layer is 0.10. More than 1.0, the rate of decrease in the tensile elastic modulus of the outermost layer after absorbing moisture under the conditions of a temperature of 20 ° C. and a humidity of 90% is 20% or more, and the outermost layer has a rate of decrease of 20% or more. A transparent multilayer film having a thickness of 20 μm or less.
[2]. The easy peel layer contains a polypropylene resin, and a test piece of the easy peel layer having a width of 25.4 mm and a thickness of 6 μm and a polypropylene layer having a thickness of 170 μm are sealed at a sealing temperature of 170 ° C. When the hot tack strength when heat-sealed is S ₁₇₀ and the hot tack strength when heat-sealed at a sealing temperature of 160 ° C is S ₁₆₀ , _{the relationship of S 170} / S ₁₆₀ ≥ 0.7 is satisfied [1]. The transparent multilayer film described in.

[3]. The transparent multilayer film according to [1] or [2], wherein the outermost layer contains polyamide or polyester.
[4]. The transparent multilayer film according to [3], wherein the outermost layer contains a biomass-derived polyamide or a biomass-derived polyester as the polyamide or polyester.
[5]. Of [1] to [4], the surface resistivity of the easy peel layer measured in accordance with JIS C 2139-3-1: 2018 is 1 × 10 ⁵ to 1 × 10 ^{14 Ω / □.} The transparent multilayer film according to any one of the items.
[6]. [1] to [5], wherein the easy peel layer contains an ethylene-based polymer having at least an ethylene-derived structural unit and a propylene-based polymer having at least a propylene-derived structural unit. The transparent multilayer film according to any one of the items.
[7]. The transparent multilayer film according to any one of [1] to [6], wherein the easy peel layer contains an anti-fog agent.
[8]. The transparent multilayer film according to any one of [1] to [7], wherein the thickness of the easy peel layer is less than 10 μm.
[9]. The transparent multilayer film according to any one of [1] to [8], wherein the transparent multilayer film further includes an intermediate layer.
[10]. The transparent multilayer film according to [9], wherein the intermediate layer contains a polyamide.
[11]. The transparent multilayer film according to [10], wherein the intermediate layer contains a biomass-derived polyamide as the polyamide.
[12]. The transparent multilayer film according to any one of [1] to [11], wherein the transparent multilayer film further includes an oxygen barrier layer.

[13]. The transparent multilayer film further includes a water vapor barrier layer, an intermediate layer, and an oxygen barrier layer, and the water vapor barrier layer and the intermediate layer are placed between the easy peel layer and the oxygen barrier layer. The transparent multilayer film according to any one of [1] to [12], which is arranged.
[14]. The transparent multilayer film according to any one of [1] to [13], wherein the transparent multilayer film further includes a water vapor barrier layer.
[15]. The transparent multilayer film according to [14], wherein the water vapor barrier layer is arranged adjacent to the easy peel layer.
[16]. The transparent multilayer film according to any one of [14] and [15], wherein the water vapor barrier layer contains polypropylene.
[17]. The transparent multilayer film according to any one of [14] to [16], wherein the water vapor barrier layer contains a crystallization nucleating agent.
[18]. The transparent multilayer film according to any one of [14] to [17], wherein the melt tension of the water vapor barrier layer is 0.2 g or more.
[19]. The transparent multilayer film according to any one of [14] to [18], wherein the water vapor barrier layer contains one kind of polypropylene or two or more kinds of polypropylenes having different melt tensions.
[20]. A packaging body comprising the transparent multilayer film according to any one of [1] to [19].

According to the present invention, there is provided a transparent multilayer film that does not cause tarmi or winding misalignment even when it absorbs moisture.

It is sectional drawing which shows typically an example of the transparent multilayer film which concerns on one Embodiment of this invention. It is sectional drawing which shows typically an example of the package which concerns on one Embodiment of this invention.

<< Transparent multilayer film >>
The transparent multilayer film according to the embodiment of the present invention is a transparent multilayer film including at least an easy peel layer and an outermost layer on the opposite side of the easy peel layer, and the easy peel layer and the outermost layer are provided. The dynamic friction coefficient between the surface layer and the surface layer is 0.10 or more and less than 1.0, and the tensile elastic modulus of the outermost layer after absorbing moisture under the conditions of a temperature of 20 ° C. and a humidity of 90%. The rate of decrease is 20% or more, and the thickness of the outermost layer is 20 μm or less.
The transparent multilayer film of the present embodiment has transparency as a whole.

The transparent multilayer film according to the present embodiment includes at least an easy peel layer and an outermost layer. The outermost layer is arranged on the opposite side of the easy peel layer.

The coefficient of dynamic friction between the easy peel layer and the outermost layer is 0.10 or more and less than 1.0.
By setting the coefficient of kinetic friction between the easy peel layer and the outermost layer to 0.10 or more and less than 1.0, it is possible to prevent tarmi and winding misalignment when the transparent multilayer film absorbs moisture.

The coefficient of kinetic friction between the easy peel layer and the outermost layer is preferably 0.12 or more and 0.98 or less, and more preferably 0.14 or more and 0.96 or less.
By setting the coefficient of kinetic friction between the easy peel layer and the outermost layer within the above range, it is possible to further improve the effect of preventing tarmi and winding misalignment when the transparent multilayer film absorbs moisture.

After leaving the outermost layer at a temperature of 20 ° C. and a humidity of 50% for 3 days, the tensile elastic modulus of the outermost layer is preferably 50 to 5000 MPa, more preferably 60 to 4900 MPa, and 70. It is more preferably ~ 4800 MPa.

After the outermost layer is allowed to absorb moisture for 3 days under the conditions of a temperature of 20 ° C. and a humidity of 90%, the tensile elastic modulus of the outermost layer is preferably 30 to 4800 MPa, more preferably 40 to 4700 MPa. It is more preferably 50 to 4600 MPa.

After the outermost layer is allowed to absorb moisture for 60 minutes under the conditions of a temperature of 20 ° C. and a humidity of 90%, the rate of decrease in the tensile elastic modulus of the outermost layer is 20% or more.
By allowing the outermost layer to absorb moisture for 60 minutes under the conditions of a temperature of 20 ° C. and a humidity of 90%, the rate of decrease in the tensile elastic modulus of the outermost layer is set to 20% or more. It is possible to prevent winding misalignment.

After the outermost layer is allowed to absorb moisture for 60 minutes under the conditions of a temperature of 20 ° C. and a humidity of 90%, the rate of decrease in the tensile elastic modulus of the outermost layer is preferably 45% or more and 95% or less, preferably 50% or more and 80. It is more preferably less than%, and even more preferably 55% or more and 65% or less.
By allowing the outermost layer to absorb moisture for 60 minutes under the conditions of a temperature of 20 ° C. and a humidity of 90%, the rate of decrease in the tensile elastic modulus of the outermost layer is within the above range. The effect of preventing deviation can be further improved.

In the transparent multilayer film according to the present embodiment, the easy peel layer contains a polypropylene resin, and has a width of 25.4 mm and a thickness of 6 μm, and a test piece of the easy peel layer having a thickness of 170 μm. When the polypropylene layer (sometimes abbreviated as "test PP layer" in this specification) is heat-sealed at a sealing temperature of 170 ° C., the hot tack strength is S _170, and the heat-sealing is performed at a sealing temperature of 160 ° C. When the hot tack strength is S ₁₆₀ , it is preferable that the relationship of _{S 170} / S _{160 ≧ 0.7 is satisfied.}

The hot tack strength is the peel strength of the seal portion when the resin component of the seal portion is in a molten state immediately after the heating seal, and can be measured using a commercially available hot tack strength measuring device. The method for measuring the hot tack strength will be described in detail later.

The transparent multilayer film of the present embodiment can be used as a lid material constituting a deep-drawn package.
The deep-drawn package is a package in which a resin bottom material provided with a recess constituting a storage portion and a lid material are joined by a heat seal or the like.

The transparent multilayer film of the present embodiment is _{used as a lid material constituting a deeply drawn package by satisfying the above-mentioned relationship of S 170} / S ₁₆₀ ≧ 0.7, and the lid material and the bottom material are heat-sealed. This makes it possible to prevent the lid material from peeling off from the bottom material when the deeply drawn package is manufactured.
In the present specification, unless otherwise specified, "peeling of the lid material from the bottom material" means "peeling of the lid material from the bottom material when manufacturing a deep-drawn package".

The transparent multilayer film of the present embodiment can also be used for producing a package other than a deeply drawn package as long as it is a package produced by a heat seal. That is, the use of the transparent multilayer film of the present embodiment is not limited to the deep-drawn package. For example, a package (a package having a tray) can be manufactured by using the transparent multilayer film of the present embodiment as a lid material and heat-sealing the cover material and the tray.
These deeply squeezed packages, packages provided with trays, and the like are suitable for cooking in a microwave oven among food packages.

The _{test piece to be measured in S 170} and S ₁₆₀ has the same composition as the easy peel layer itself in the transparent multilayer film or the easy peel layer in the transparent multilayer film, and is separately produced. The width was adjusted to 25.4 mm and the thickness was adjusted to 6 μm by using an easy peel layer for testing.

S ₁₇₀ is a peel strength (N / 25.4 mm) measured when the test piece of the easy peel layer and the PP layer for testing are heat-sealed at a sealing temperature of 170 ° C., and is measured by a known method. can.
At this time, the entire surface of one surface of the test piece of the easy peel layer is superposed on one surface of the test PP layer, and these are heat-sealed in this state.

At the time of measuring S ₁₇₀ , the sealing pressure could be 0.473 N / mm ² and the sealing time was 1.0 sec. Can be.
The time from the completion of the heating seal to the measurement of the _{peel strength (S 170) is 500 msec.} Can be.
The peel strength (S ₁₇₀ ) can be measured by peeling the test piece of the easy peel layer from the PP layer for testing after heating and sealing. The tensile speed at this time was 33.3 mm / sec. , The angle at the time of peeling can be 90 °.

The PP layer for testing has a thickness of 170 μm, and its size is particularly large if it is possible to superimpose the test pieces of the easy peel layer as described above and peel off the test pieces of the easy peel layer. Not limited.

S ₁₆₀ is a peel strength (N / 25.4 mm) measured when the test piece of the easy peel layer and the PP layer for testing are heat-sealed at a sealing temperature of 160 ° C.
S ₁₆₀ can be measured by the same method as in _{S 170} , except that the heating seal temperature is 160 ° C. instead of 170 ° C.

In the present embodiment, S ₁₇₀ / S ₁₆₀ (sometimes referred to as “hot tack strength ratio” in the present specification) is preferably 0.7 or more, and more preferably 0.75 or more. It is preferably 0.8 or more, and more preferably 0.8 or more. The _{larger the S 170} / S _{160, the} higher the effect of suppressing the peeling of the lid material from the bottom material tends to be.

The upper limit of S ₁₇₀ / S ₁₆₀ is not particularly limited.
_{For example, S 170} / S ₁₆₀ may be 0.99 or less in that other properties of the transparent multilayer film are better.

S ₁₇₀ / S ₁₆₀ can be appropriately adjusted within a range set by arbitrarily combining any of the above-mentioned lower limit values and upper limit values. For example, in one embodiment, S ₁₇₀ / S ₁₆₀ may be any of 0.7 to 0.99, 0.75 to 0.99, and 0.8 to 0.99. However, these are examples of _{S 170} / S _160.

S ₁₇₀ is not particularly limited as long as the above-mentioned S ₁₇₀ / S _{160 relationship is satisfied.}
S ₁₇₀ is preferably 4.3 N / 25.4 mm or more, preferably 7.3 N / 25.4 mm or less, and may be, for example, 4.3 to 7.3 N / 25.4 mm. ..

S ₁₆₀ is not particularly limited as long as the above-mentioned S ₁₇₀ / S _{160 relationship is satisfied.}
S ₁₆₀ is preferably 4.5 N / 25.4 mm or more, preferably 7.5 N / 25.4 mm or less, and may be, for example, 4.5 to 7.5 N / 25.4 mm. ..

The transparent multilayer film of the present embodiment may include at least the easy peel layer and the outermost layer on the opposite side of the easy peel layer, and usually, the easy peel layer and the outermost layer and other layers are provided. The layer is provided with one type or two or more types, and the layers other than the easy peel layer and the outermost layer are arbitrary layers. The transparent multilayer film of the present embodiment may or may not include any of these layers. The arbitrary layer included in the transparent multilayer film can be appropriately selected depending on the intended purpose.

For example, the transparent multilayer film may further include a water vapor barrier layer for suppressing the permeation of water vapor in addition to the easy peel layer and the outermost layer. The transparent multilayer film provided with the water vapor barrier layer is excellent in the water vapor barrier layer.
For example, the transparent multilayer film may further include an oxygen barrier layer for suppressing oxygen permeation in addition to the easy peel layer and the outermost layer. The transparent multilayer film provided with the oxygen barrier layer is excellent in the oxygen barrier layer.
For example, the transparent multilayer film may further include an intermediate layer in addition to the easy peel layer and the outermost layer. Examples of the intermediate layer include a layer for imparting molding processability to the transparent multilayer film and for suppressing the occurrence of pinholes in the transparent multilayer film so that the intermediate layer does not become the outermost layer in the transparent multilayer film. Be placed.
For example, the transparent multilayer film may further include an adhesive layer for adhering two layers constituting the transparent multilayer film, in addition to the easy peel layer and the outermost layer. A transparent multilayer film provided with an adhesive layer has a more stable multilayer structure. The adhesive layer is arranged so as not to be the outermost layer in the transparent multilayer film.

The transparent multilayer film of the present embodiment includes at least the easy peel layer and the outermost layer on the opposite side of the easy peel layer, and further comprises the water vapor barrier layer, the oxygen barrier layer, the intermediate layer, and the adhesive layer. It is preferable to have one or more kinds selected from the group, and all of the easy peel layer, the water vapor barrier layer, the oxygen barrier layer, the intermediate layer, the outermost layer and the adhesive layer may be provided.

Hereinafter, the present invention will be described in detail with reference to the drawings. In addition, in the figure used in the following description, in order to make it easy to understand the features of the present invention, the main part may be enlarged and shown, and the dimensional ratio of each component is the same as the actual one. Is not always the case.

FIG. 1 is a cross-sectional view schematically showing an example of a transparent multilayer film of the present embodiment.
The transparent multilayer film 1 shown here is composed of an easy peel layer 11, a water vapor barrier layer 12, an intermediate layer 13, an oxygen barrier layer 14, and an outermost layer 15.
In the transparent multilayer film 1, the water vapor barrier layer 12 and the intermediate layer 13 are arranged between the easy peel layer 11 and the oxygen barrier layer 14. Further, the water vapor barrier layer 12 is arranged adjacent to the easy peel layer 11.
Further, the transparent multilayer film 1 includes the outermost layer 15 on the side of the oxygen barrier layer 14 opposite to the intermediate layer 13 side.
Further, the transparent multilayer film 1 includes an adhesive layer 19 between the water vapor barrier layer 12 and the intermediate layer 13.
That is, the transparent multilayer film 1 is composed of an easy peel layer 11, a water vapor barrier layer 12, an adhesive layer 19, an intermediate layer 13, an oxygen barrier layer 14, and an outermost layer 15 laminated in this order in these thickness directions. ing.

<Easy peel layer>
The easy peel layer 11 is one of the outermost layers of the transparent multilayer film 1, and is arranged on the outermost side of the transparent multilayer film 1 in the stacking direction of each layer constituting the transparent multilayer film 1.
A package can be constructed by sealing the transparent multilayer film 1 with another film or sheet by the easy peel layer 11 in the transparent multilayer film 1. The surface of the easy peel layer 11 opposite to the water vapor barrier layer 12 side (sometimes referred to as the "first surface" in the present specification) 11a is an exposed surface in the transparent multilayer film 1 and is another surface. It is a sealing surface for sealing with a film or sheet.
The easy peel layer 11 has transparency.

The easy peel layer 11 may contain a polypropylene-based resin.
The polypropylene-based resin contained in the easy peel layer 11 is not particularly limited as long as it is a resin having a constituent unit derived from propylene.

Examples of the polypropylene-based resin contained in the easy peel layer 11 include a propylene homopolymer (that is, homopolypropylene, which may be referred to as "hPP" in the present specification) and a propylene-based copolymer. Be done.

The propylene-based copolymer has a structural unit derived from propylene and a structural unit derived from a monomer other than propylene.
Examples of the propylene-based copolymer include a propylene-ethylene random copolymer (also known as polypropylene random copolymer, which may be referred to as "rPP" in the present specification) and a propylene-ethylene block copolymer (also known as "rPP"). : Polypropylene block copolymer, which may be referred to as "bPP" in the present specification), propylene-butene copolymer and the like.

The polypropylene-based resin contained in the easy peel layer 11 may be only one type, may be two or more types, and when there are two or more types, the combination and ratio thereof may be determined according to the purpose. It can be selected arbitrarily. For example, the easy peel layer 11 contains a propylene homopolymer and does not have to contain a propylene-based copolymer, or contains one or more propylene-based copolymers and has a propylene monopoly weight. It may not contain a coalescence, or may contain a propylene homopolymer and may contain one or more propylene-based copolymers.

The easy peel layer 11 may contain only the polypropylene-based resin as a resin component, or may contain both the polypropylene-based resin and a resin other than the polypropylene-based resin.

The resin other than the polypropylene-based resin contained in the easy peel layer 11 is not particularly limited as long as it is a resin having no constituent unit derived from propylene.

Examples of the resin other than the polypropylene-based resin contained in the easy peel layer 11 include an ethylene homopolymer (polyethylene) and an ethylene-based copolymer.

Examples of the ethylene homopolymer include low density polyethylene (LDPE), linear low density polyethylene (LLDPE), metallocene-catalyzed linear low density polyethylene (metallocene LLDPE), medium density polyethylene (MDPE), and high density polyethylene. (HDPE) and the like. These ethylene homopolymers are treated as resins of different types.

The ethylene homopolymer contained in the easy peel layer 11 may be polyethylene derived from biomass. By using polyethylene derived from biomass in the transparent multilayer film 1, the amount of petroleum resources used can be reduced, and the amount of carbon dioxide emitted during the production and disposal of the transparent multilayer film 1 can be reduced. That is, such a transparent multilayer film 1 has a remarkable effect in that the environmental load can be reduced. The transparent multilayer film 1 in which the easy peel layer 11 contains polyethylene derived from biomass as the ethylene homopolymer is a preferable example.

Examples of the biomass-derived polyethylene include plant-derived polyethylene such as carbon-neutral sugar cane.
Examples of the biomass-derived polyethylene include low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), metallocene-catalyzed linear low-density polyethylene (metallocene LLDPE), medium-density polyethylene (MDPE), and high density polyethylene. Examples include density polyethylene (HDPE). These ethylene homopolymers are treated as resins of different types.

When the easy peel layer 11 contains the polyethylene derived from the biomass, the polyethylene may contain only the polyethylene derived from the biomass, or both the polyethylene derived from the biomass and the polyethylene not derived from the biomass. May be.

When the easy peel layer 11 contains the ethylene homopolymer (polyethylene), the total content of polyethylene in the easy peel layer 11 (the total content of non-biomass-derived polyethylene and biomass-derived polyethylene). The proportion of the content of polyethylene derived from biomass may be, for example, 3% by mass or more, 20% by mass or more, 50% by mass or more, 70% by mass or more, and 90% by mass or more, and is 100% by mass. That is, the polyethylene contained in the easy peel layer 11 may be all biomass-derived polyethylene. The higher the ratio, the higher the effect of reducing the environmental load on the transparent multilayer film 1.

The ethylene-based copolymer has a structural unit derived from ethylene and a structural unit derived from another monomer that does not correspond to either ethylene or propylene.
Examples of the ethylene-based copolymer include an ethylene-butene copolymer and the like.

The resin other than the polypropylene-based resin contained in the easy peel layer 11 may be only one type, may be two or more types, and when there are two or more types, the combination and ratio thereof may be determined. It can be selected arbitrarily according to the purpose. For example, the easy peel layer 11 may contain one or more kinds of ethylene homopolymers and may not contain one kind or two or more kinds of ethylene-based copolymers, or one kind or two or more kinds of ethylene-based copolymers. It does not have to contain an ethylene homopolymer, it contains one or more kinds of ethylene homopolymers, and it contains one kind or two or more kinds of ethylene-based copolymers. May be good.

The ratio of the content of the polypropylene-based resin to the total mass of the easy peel layer 11 in the easy peel layer 11 may be, for example, 55 to 80% by mass or 60 to 80% by mass. When the ratio is at least the lower limit value, the easy peel property of the easy peel layer 11 is further improved. When the ratio is not more than the upper limit value, the effect obtained by the easy peel layer 11 containing a component not corresponding to the polypropylene-based resin becomes higher.

The easy peel layer 11 may contain an ethylene-based polymer having at least an ethylene-derived structural unit and a propylene-based polymer having at least a propylene-derived structural unit.

As the preferable easy peel layer 11, for example, the polypropylene-based resin contains a propylene homopolymer, and the following general formulas (i) -1 and (i) -2:

（式中、Ｒ^１及びＲ^２は、それぞれ独立に水素原子、メチル基又はエチル基であり、ただし、Ｒ^１及びＲ^２が互いに同じとなることはない。）
で表される構成単位を有する（ただし、前記一般式（ｉ）−１で表される構成単位の数が、前記一般式（ｉ）−２で表される構成単位の数よりも多い）ポリオレフィン系共重合体（本明細書においては、「ポリオレフィン系共重合体（Ｉ）」と略記することがある）を含有するか、若しくは、前記ポリオレフィン系共重合体（Ｉ）及びポリエチレンを含有しており、前記イージーピール層における、前記イージーピール層の総質量に対する、前記プロピレン単独重合体の含有量の割合が、５５質量％以上である（本明細書においては、このようなイージーピール層を「イージーピール層（Ａ）」と称することがある）か、又は、
前記イージーピール層が、前記ポリプロピレン系樹脂として、プロピレン系共重合体を含有するか、若しくは、前記プロピレン系共重合体及びプロピレン単独重合体を含有し、さらに、前記ポリオレフィン系共重合体（Ｉ）のうち、前記Ｒ^１及びＲ^２がともにメチル基ではない非プロピレン系共重合体を含有するか、若しくは、前記非プロピレン系共重合体及びポリエチレンを含有しており、前記イージーピール層における、前記イージーピール層の総質量に対する、前記プロピレン系共重合体及びプロピレン単独重合体の合計含有量の割合が、５５質量％以上である（本明細書においては、このようなイージーピール層を「イージーピール層（Ｂ）」と称することがある）、ものが挙げられる。

(In the formula, R ¹ and R ² are independently hydrogen atoms, methyl groups or ethyl groups, respectively, but R ¹ and R ² are not the same as each other.)
Polyolefin having a structural unit represented by (however, the number of structural units represented by the general formula (i) -1 is larger than the number of structural units represented by the general formula (i) -2). It contains a system copolymer (in this specification, it may be abbreviated as "polyolefin-based copolymer (I)"), or contains the polyolefin-based copolymer (I) and polyethylene. The ratio of the content of the propylene copolymer to the total mass of the easy peel layer in the easy peel layer is 55% by mass or more (in the present specification, such an easy peel layer is referred to as "the easy peel layer". (Sometimes referred to as "easy peel layer (A)") or
The easy peel layer contains a propylene-based copolymer as the polypropylene-based resin, or contains the propylene-based copolymer and the propylene homopolymer, and further, the polyolefin-based copolymer (I). Among them, the ^{non-propylene-based copolymer in which both R 1} and R ² are not methyl groups are contained, or the non-propylene-based copolymer and polyethylene are contained, and the said in the easy peel layer. The ratio of the total content of the propylene-based copolymer and the propylene homopolymer to the total mass of the easy peel layer is 55% by mass or more (in the present specification, such an easy peel layer is referred to as "easy peel". (Sometimes referred to as "layer (B)"), and the like.

The ratio of the content of the propylene homopolymer to the total mass of the easy peel layer in the easy peel layer is usually the total content of components that do not vaporize at room temperature in the composition for forming the easy peel layer described later ( It is the same as the ratio of the content (parts by mass) of the propylene homopolymer to the mass part).
The ratio of the total content of the propylene-based copolymer and the propylene homopolymer to the total mass of the easy peel layer in the easy peel layer is usually vaporized at room temperature in the composition for forming an easy peel layer described later. It is the same as the ratio of the total content (parts by mass) of the propylene-based copolymer and the propylene homopolymer to the total content (parts by mass) of the components not to be added.

In addition, in this specification, "room temperature" means a temperature which is not particularly cooled or heated, that is, a normal temperature, and examples thereof include a temperature of 15 to 25 ° C.

In other words, the easy peel layer (A) contains a propylene homopolymer and a polyolefin-based copolymer (I), and may or may not contain polyethylene. The ratio of the content of the propylene copolymer to the total mass of the easy peel layer in the easy peel layer is 55% by mass or more.

In other words, the easy peel layer (B) contains a propylene-based copolymer, and among the polyolefin-based copolymers (I), the non-propylene-based copolymer is contained, and a propylene homopolymer. May or may not be contained, polyethylene may be contained, or may not be contained, and the total mass of the easy peel layer in the easy peel layer. The ratio of the total content of the propylene-based copolymer and the propylene homopolymer is 55% by mass or more.

In the polyolefin-based copolymer (I), R ¹ and R ² are independently hydrogen atoms, methyl groups, or ethyl groups, respectively, but R ¹ and R ² are not the same as each other. That is, the ethylene homopolymer (polyethylene, PE), the propylene homopolymer (homopolypropylene, hPP) and the butene homopolymer (polybutene, PB) are not included in the polyolefin-based copolymer (I).
Since the easy peel layer 11 contains the polyolefin-based copolymer (I), the above-mentioned effect of suppressing peeling of the lid material from the bottom material can be obtained.

In the polyolefin-based copolymer (I), the number of structural units represented by the general formula (i) -1 is more than 50% of the total number of all structural units (total number of structural units), which is 100. Less than%.
In the polyolefin-based copolymer (I), the number of structural units represented by the general formula (i) -2 is more than 0% with respect to the number of all structural units (total number of structural units), which is 50. Less than%.

The ratio of the total content of the propylene-based copolymer and the propylene homopolymer to the total mass of the easy peel layer (B) in the easy peel layer (B) is preferably 60% by mass or more, preferably 65% by mass. % Or more is more preferable, and for example, it may be either 70% by mass or more and 75% by mass or more. When the ratio is at least the lower limit value, the easy peel property of the easy peel layer (B) is further improved. For example, when the lid material is peeled from the bottom material, the effect of suppressing stringing is enhanced.
Threading is a phenomenon in which when the film is sealed with the object to be sealed and then peeled from the object to be sealed, the resin component is pulled between the peeled parts and the peeled surface is not flattened. be. In the case of the present embodiment, when the lid material heat-sealed with the bottom material or tray is peeled off from the bottom material or tray, stringing occurs between the bottom material or tray and the lid material. It is suppressed.

The ratio of the total content of the propylene-based copolymer and the propylene homopolymer to the total mass of the easy peel layer (B) in the easy peel layer (B) is preferably 80% by mass or less. When the ratio is not more than the upper limit value, the easy peel layer (B) contains a component which does not correspond to any of the propylene-based copolymer and the propylene homopolymer. The effect is higher.

The ratio of the total content of the propylene-based copolymer and the propylene homopolymer to the total mass of the easy peel layer (B) in the easy peel layer (B) is the lower limit value and the upper limit value of any of the above. , Can be adjusted as appropriate within the range set by any combination. For example, in one embodiment, the proportion may be any of 55-80% by mass, 60-80% by mass, 65-80% by mass, 70-80% by mass, and 75-80% by mass. However, these are examples of the above ratio.

The ratio of the total content of the non-propylene copolymer and polyethylene to the total mass of the easy peel layer (B) in the easy peel layer (B) is preferably 10% by mass or more, preferably 15% by mass or more. Is more preferable, and for example, it may be 20% by mass or more. When the ratio is at least the lower limit value, the above-mentioned effect of suppressing peeling of the lid material from the bottom material becomes higher.

The ratio of the total content of the non-propylene copolymer and polyethylene to the total mass of the easy peel layer (B) in the easy peel layer (B) may be, for example, 40% by mass or less, but 35. It is preferably mass% or less. When the ratio is not more than the upper limit value, the effect obtained by the easy peel layer (B) containing a component which does not correspond to any of the non-propylene copolymer and the polyethylene. But it gets higher.

The ratio of the total content of the non-propylene copolymer and polyethylene to the total mass of the easy peel layer (B) in the easy peel layer (B) is the lower limit value and the upper limit value of any of the above. It can be adjusted as appropriate within the range set by any combination. For example, in one embodiment, the proportion may be any of 10-40% by mass, 10-35% by mass, 15-35% by mass, and 20-35% by mass. However, these are examples of the above ratio.

The ratio of the content of the propylene homopolymer to the total mass of the easy peel layer (A) in the easy peel layer (A) is the total of the easy peel layer (B) in the easy peel layer (B) described above. The ratio of the total content of the propylene-based copolymer and the propylene homopolymer to the mass can be the same.

The ratio of the total content of the polyolefin-based copolymer (I) and polyethylene to the total mass of the easy peel layer (A) in the easy peel layer (A) is the ratio of the total contents of the polyolefin-based copolymer (I) and polyethylene in the easy peel layer (B) described above. The ratio of the total content of the non-propylene copolymer and polyethylene to the total mass of the peel layer (B) can be the same.

The easy peel layer 11 does not fall under any of the propylene homopolymer, the polyolefin-based copolymer (I), the polyethylene, and the propylene-based copolymer, as long as the effects of the present invention are not impaired. May contain the components of.

Examples of the other components contained in the easy peel layer 11 include anti-fog agents, anti-blocking agents, antistatic agents and the like. The other component may be a component having two or more functions (expressing two or more actions) in one kind.
Among them, the easy peel layer 11 preferably contains an anti-fog agent as the other component.

The anti-fog agent contained in the easy peel layer 11 is a component for suppressing fogging of the transparent multilayer film 1, particularly fogging on the exposed surface of the easy peel layer 11. In the transparent multilayer film 1 in which the easy peel layer 11 contains an anti-fog agent, the haze can be reduced. The haze of the transparent multilayer film will be described separately later.

In the present specification, the haze of the transparent multilayer film means a haze measured from the outside on the easy peel layer side of the transparent multilayer film unless otherwise specified.

The anti-fog agent contained in the easy peel layer 11 may be a known one. Examples of the anti-fog agent include polyglycen fatty acid ester and diglycerin fatty acid ester.

The anti-fog agent contained in the easy peel layer 11 may be only one type, may be two or more types, and when there are two or more types, the combination and ratio thereof are arbitrary depending on the purpose. Can be selected.

When an anti-fog agent is used, the ratio of the content of the anti-fog agent to the total mass of the easy peel layer 11 in the easy peel layer 11 is preferably 0.5 to 5% by mass, preferably 0.8 to 4 It is more preferably 3% by mass. When the ratio is at least the lower limit value, the effect of using the anti-fog agent can be obtained more remarkably. When the ratio is not more than the upper limit value, the characteristics of the transparent multilayer film 1 not derived from the anti-fog agent become better.
The ratio is usually the same as the ratio of the antifogging agent content (parts by mass) to the total content (parts by mass) of the components that do not vaporize at room temperature in the composition for forming an easy peel layer described later.

The anti-blocking agent is such that when the transparent multilayer films 1 are laminated, or when the transparent multilayer film 1 and another film or sheet are laminated, the transparent multilayer films 1 are stuck to each other or the transparent multilayer film 1 is laminated. It is a component for suppressing sticking (blocking) between 1 and a film or sheet adjacent thereto. The mode of "stacking the transparent multilayer films 1 on top of each other" also includes a mode of "winding one transparent multilayer film 1 in a roll shape".

The anti-blocking agent contained in the easy peel layer 11 may be a known one. Examples of the anti-blocking agent include silica such as natural silica and synthetic silica.

The anti-blocking agent contained in the easy peel layer 11 may be only one type, may be two or more types, and when there are two or more types, the combination and ratio thereof are arbitrary depending on the purpose. Can be selected.

When an anti-blocking agent is used, the ratio of the content of the anti-blocking agent to the total mass of the easy peel layer 11 in the easy peel layer 11 is preferably 0.05 to 3.0% by mass, preferably 0.1. More preferably, it is ~ 2.5% by mass. When the ratio is at least the lower limit value, the effect of using the anti-blocking agent can be obtained more remarkably. When the ratio is not more than the upper limit value, the characteristics of the transparent multilayer film 1 not derived from the anti-blocking agent become better.
The ratio is usually the same as the ratio of the content of the antiblocking agent (parts by mass) to the total content (parts by mass) of the components that do not vaporize at room temperature in the composition for forming an easy peel layer described later.

The antistatic agent contained in the easy peel layer 11 is a component for reducing the resistivity of the transparent multilayer film 1, for example, the surface resistivity.
The antistatic agent contained in the easy peel layer 11 may be a known one.

When an antistatic agent is used, the ratio of the content of the antistatic agent to the total mass of the easy peel layer 11 in the easy peel layer 11 is, for example, the ratio of the content of the antistatic agent in the easy peel layer 11 described above. It may be similar to the ratio of the antistatic agent content to the total mass.

The surface resistivity of the easy peel layer 11 (for example, the surface resistivity on the first surface 11a) measured according to JIS C 2139-3-1: 2018 is 1 × 10 ⁵ to 1 × 10 ¹⁴ Ω. It is preferably / □, and may be, for example, either 5 × 10 ^{5 to} 5 × 10 ¹³ Ω / □ and 5 × 10 ⁵ to 1 × 10 ¹³ Ω / □. When the surface resistance of the easy peel layer 11 is equal to or less than the upper limit value, a package is manufactured using the transparent multilayer film 1, and the object containing powder is packaged using this package. The effect of suppressing the sticking of the powder to the easy peel layer is enhanced. On the other hand, the easy peel layer 11 having a surface resistivity of not less than the lower limit value is easier to prepare.

The surface resistivity of the easy peel layer 11 can be adjusted by, for example, adjusting the type and content of the components contained in the easy peel layer 11, and for example, adjusting the content of the antistatic agent in the easy peel layer 11. Allows for easy adjustment.

The easy peel layer 11 may be composed of one layer (single layer) or may be composed of two or more layers. When the easy peel layer 11 is composed of a plurality of layers, the plurality of layers may be the same or different from each other, and the combination of the plurality of layers is not particularly limited as long as the effects of the present invention are not impaired.

In the present specification, not only in the case of the easy peel layer 11, "a plurality of layers may be the same or different from each other" means "all layers may be the same or all layers". May be different, or only some of the layers may be the same. ”Furthermore,“ a plurality of layers are different from each other ”means that“ at least one of the constituent materials and the thickness of each layer is different from each other. It means "different".

The ratio of the thickness of the easy peel layer 11 to the thickness of the transparent multilayer film 1 is preferably 8 to 18%, more preferably 10 to 14%. When the ratio is equal to or higher than the lower limit value, the sealing strength of the easy peel layer 11 becomes higher within an appropriate range. When the ratio is not more than the upper limit value, it is possible to avoid an excessive thickness.
The thickness of the easy peel layer 11 is preferably less than 10 μm, and may be, for example, 4 to 9 μm.

In this specification, as will be described later, not only the easy peel layer 11, but also the water vapor barrier layer 12, the intermediate layer 13, the oxygen barrier layer 14, the outermost layer 15, and the adhesive layer 19 are each transparent multilayer film. Although the ratio of these thicknesses to the thickness of 1 is described, in the transparent multilayer film 1, the total of the ratios of the thicknesses of all these layers shall not exceed 100%.

In the present specification, the "thickness of the transparent multilayer film" means the "total thickness of the transparent multilayer film", and in the case of the transparent multilayer film 1, the thickness of the easy peel layer 11 and the water vapor barrier layer. It is the total value of the thickness of 12, the thickness of the intermediate layer 13, the thickness of the oxygen barrier layer 14, the thickness of the outermost layer 15, and the thickness of the adhesive layer 19.

When the easy peel layer 11 is composed of a plurality of layers, the total thickness of the plurality of layers may satisfy the condition of the preferable ratio of the thickness of the easy peel layer 11 to be the thickness.

<Water vapor barrier layer>
The water vapor barrier layer 12 is arranged adjacent to the easy peel layer 11. In the transparent multilayer film of the present embodiment, it is preferable that the water vapor barrier layer is laminated in contact with the easy peel layer in this way.
The water vapor barrier layer 12 has transparency.

The water vapor barrier layer 12 is preferably a resin layer containing a water vapor barrier resin having a water vapor barrier property.

Examples of the water vapor barrier resin include polyethylenes such as low-density polyethylene (LDPE), medium-density polyethylene (MDPE), and high-density polyethylene (HDPE); ethylene-α-olefin copolymer; polypropylene; propylene-ethylene random copolymer. Propylene-ethylene block copolymer; propylene-α-olefin copolymer; ethylene-cyclic olefin copolymer obtained by copolymerizing a cyclic olefin such as cyclopentadiene or norbornene; ethylene-vinyl acetate copolymer (EVA) Resin); partially saponified or completely saponified product of ethylene-vinyl acetate copolymer; ethylene- (meth) acrylic acid copolymer or esterified product thereof or ionic crosslinked product; ethylene- (meth) acrylic acid- (meth) acrylic Examples thereof include an acid ester ternary copolymer; maleic anhydride-modified polyethylene; maleic anhydride-polyethylene copolymer and the like.
Among these, the water vapor barrier layer 12 preferably contains polypropylene.

In addition, in this specification, "(meth) acrylic acid" is a concept including both "acrylic acid" and "methacrylic acid". The same applies to terms similar to (meth) acrylic acid.

The component exhibiting the water vapor barrier property (for example, the water vapor barrier resin) contained in the water vapor barrier layer 12 may be only one type, two or more types, or two or more types. , Their combinations and ratios can be arbitrarily selected according to the purpose.

The water vapor barrier layer 12 may contain other components in addition to the component exhibiting the water vapor barrier property (for example, the water vapor barrier resin) as long as the water vapor barrier property is not impaired.
The other components contained in the water vapor barrier layer 12 may be only one type, may be two or more types, and when there are two or more types, the combination and ratio thereof may be determined according to the purpose. It can be selected arbitrarily.

In the water vapor barrier layer 12, the ratio of the content of the component exhibiting the water vapor barrier property to the total mass of the water vapor barrier layer 12 (for example, the ratio of the content of the water vapor barrier resin) is 50 to 100% by mass. Is preferable, and 70 to 100% by mass is more preferable. When the ratio is at least the lower limit value, the water vapor barrier property of the water vapor barrier layer 12 becomes higher.
The ratio is usually the ratio of the content (parts by mass) of the component exhibiting the water vapor barrier property to the total content (parts by mass) of the component that does not vaporize at room temperature in the composition for forming the water vapor barrier layer described later. It is the same.

Examples of the other components contained in the water vapor barrier layer 12 include a crystallization nucleating agent and an anti-fog agent.
That is, the water vapor barrier layer 12 may contain a crystallization nucleating agent or may contain an anti-fog agent.

The crystallization nucleating agent is a component for improving the transparency of the water vapor barrier layer 12 by controlling the crystal growth in the water vapor barrier layer 12.
The crystallization nucleating agent may be a known one. Examples of the crystallization nucleating agent include sorbitol-based crystallization nucleating agents.

The crystallization nucleating agent contained in the water vapor barrier layer 12 may be only one type, may be two or more types, and when there are two or more types, the combination and ratio thereof may be determined according to the purpose. It can be selected arbitrarily.

When a crystallization nucleating agent is used, the ratio of the content of the crystallization nucleating agent to the total mass of the water vapor barrier layer 12 in the water vapor barrier layer 12 is preferably 0.05 to 3.0% by mass, and is 0. .1 to 2.5% by mass is more preferable. When the ratio is at least the lower limit value, the effect of using the crystallization nucleating agent can be obtained more remarkably. When the ratio is not more than the upper limit value, the characteristics of the water vapor barrier layer 12 not derived from the crystallization nucleating agent become better.
The ratio is usually the same as the ratio of the content (parts by mass) of the crystallization nucleating agent to the total content (parts by mass) of the components that do not vaporize at room temperature in the composition for forming a water vapor barrier layer described later. ..

The anti-fog agent is a component for suppressing fogging of the transparent multilayer film 1, particularly fogging on the exposed surface of the easy peel layer 11.
The anti-fog agent contained in the water vapor barrier layer 12 may be a known one, and specific examples thereof include the same anti-fog agent contained in the above-mentioned easy peel layer 11.

The anti-fog agent contained in the water vapor barrier layer 12 may be only one type, two or more types, and when two or more types, the combination and ratio thereof are arbitrary depending on the purpose. Can be selected.

When an antifogging agent is used, the ratio of the content of the antifogging agent to the total mass of the water vapor barrier layer 12 in the water vapor barrier layer 12 is preferably 0.05 to 3.0% by mass, preferably 0.1. More preferably, it is ~ 2.5% by mass. When the ratio is at least the lower limit value, the effect of using the anti-fog agent can be obtained more remarkably. When the ratio is not more than the upper limit value, the characteristics of the transparent multilayer film 1 not derived from the anti-fog agent become better.
The ratio is usually the same as the ratio of the anti-fog agent content (parts by mass) to the total content (parts by mass) of the components that do not vaporize at room temperature in the composition for forming a water vapor barrier layer described later.

The melt tension of the water vapor barrier layer 12 may be 0.2 g or more. Among the transparent multilayer films 1, when the melt tension of the water vapor barrier layer 12 that is most likely to cause surging is equal to or higher than the lower limit, surging of the entire transparent multilayer film 1 is suppressed.

Surging is a state in which the thickness of the target film fluctuates periodically. In the case of a multilayer film, when the film is formed by a method involving heating such as a coextrusion method and manufactured, the thickness of any of the layers fluctuates periodically (surging occurs). , Surging occurs throughout the multilayer film. Surging during film formation may be likely to occur depending on the film formation conditions, and usually, the constituent material of the steam barrier layer is likely to cause surging, and this tendency becomes stronger when the film formation temperature is set low. .. That is, the multilayer film provided with the water vapor barrier layer is likely to cause surging.

On the other hand, in the steam barrier layer 12 having the lowest melt tension, when the transparent multilayer film 1 having a high melt tension of 0.2 g or more is produced, even if the film formation temperature is low, the film formation temperature is usually low. In any layer, surging can be suppressed, and surging of the entire transparent multilayer film 1 is suppressed.
In addition, in this specification, "melting tension" means "melting tension at 230 degreeC" unless otherwise specified. The melt tension can be measured using a capillograph according to JIS K7199: 1999.

The melt tension of the water vapor barrier layer 12 may be, for example, 0.3 g or more, 0.5 g or more, and 0.7 g or more in that the above-mentioned effect becomes higher.

The upper limit of the melting tension of the water vapor barrier layer 12 is not particularly limited. For example, the melt tension of the water vapor barrier layer 12 is preferably 1 g or less in that the water vapor barrier layer 12 is relatively easy to form.

The melting tension of the water vapor barrier layer 12 can be appropriately adjusted within a range set by arbitrarily combining the above-mentioned lower limit value and upper limit value. For example, in one embodiment, the melt tension of the water vapor barrier layer 12 may be any of 0.2 to 1 g, 0.3 to 1 g, 0.5 to 1 g, and 0.7 to 1 g. However, these are examples of the melt tension of the water vapor barrier layer 12.

The melt tension of the water vapor barrier layer 12 can be adjusted by adjusting the type and content of the components contained in the water vapor barrier layer 12, such as the water vapor barrier resin.
The components contained in the water vapor barrier layer 12 exhibit a unique melt tension depending on the type (in other words, form a film or sheet having a unique melt tension). And the content can be selected.

In terms of the higher melt tension of the water vapor barrier layer 12, the water vapor barrier layer 12 preferably contains, for example, a resin having branched chains, and more preferably contains a resin having many branched chains.

For example, the water vapor barrier layer 12 may contain one kind of polypropylene, or may contain two or more kinds of polypropylene having different melt tensions. For example, when only one type of polypropylene is selected, it may be difficult to set the melt tension of the water vapor barrier layer 12 to a desired value. In that case, the melt tension of the water vapor barrier layer 12 can be easily set by using two or more kinds of polypropylenes having different melt tensions in combination. That is, the melt tension of the water vapor barrier layer 12 can be easily adjusted by using polypropylene having a low melt tension and polypropylene having a high melt tension in combination in consideration of these melt tensions. For example, a polypropylene having a high melt tension is preferable, and a metallocene-based high melt tension polypropylene (in other words, a metallocene-catalyzed high melt tension polypropylene) can be mentioned.

Here, the case where the melt tension of the water vapor barrier layer 12 is adjusted by using polypropylene has been described, but the melt tension may be adjusted by using a component other than polypropylene.

For example, when the first component and the second component having a higher melt tension than the first component are used in combination as the contained component of the water vapor barrier layer 12 to adjust the melt tension of the water vapor barrier layer 12, the water vapor barrier is used. In layer 12, the ratio of the content of the second component (parts by mass) to the content (parts by mass) of the first component ([content of the second component of the water vapor barrier layer 12 (parts by mass)] / [steam barrier] The content (parts by mass) of the first component of the layer 12] × 100) is preferably 1 to 99% by mass, more preferably 3 to 97% by mass, and 6 to 94% by mass. Is more preferable, for example, it may be any of 6 to 80% by mass, 6 to 60% by mass, 6 to 40% by mass, and 6 to 20% by mass.

Water vapor permeability of the water vapor barrier layer 12 is, for example, 40 ° C., in an atmosphere of 90% RH (relative humidity), is preferably not more than 100g ^/ m 2 · day.
The amount of water vapor permeation of the water vapor barrier layer 12 can be measured according to, for example, JIS Z 0208.

The water vapor barrier layer 12 may be composed of one layer (single layer) or may be composed of two or more layers. When the water vapor barrier layer 12 is composed of a plurality of layers, the plurality of layers may be the same or different from each other, and the combination of the plurality of layers is not particularly limited as long as the effects of the present invention are not impaired.

The ratio of the thickness of the water vapor barrier layer 12 to the thickness of the transparent multilayer film 1 is preferably 16 to 30%, more preferably 20 to 26%. When the ratio is at least the lower limit value, the water vapor barrier property of the water vapor barrier layer 12, in other words, the water vapor barrier property of the transparent multilayer film 1 is further improved. When the ratio is not more than the upper limit value, it is possible to avoid an excessive thickness.
The thickness of the water vapor barrier layer 12 may be, for example, 8 to 15 μm.

When the water vapor barrier layer 12 is composed of a plurality of layers, the total thickness of the plurality of layers may satisfy the condition of the preferable ratio of the thickness of the water vapor barrier layer 12 to be the thickness.

<Middle class>
The intermediate layer 13 imparts molding processability to the transparent multilayer film 1 and suppresses the occurrence of pinholes in the transparent multilayer film 1.
The intermediate layer 13 has transparency.

The intermediate layer 13 preferably contains a nitrogen-containing resin as a constituent material thereof.
The nitrogen-containing resin preferably has a nitrogen atom in its main chain.
Among them, from the viewpoint of higher effect, it is more preferable that the nitrogen-containing resin is polyamide, that is, the intermediate layer 13 contains polyamide.

Examples of the polyamide include cyclic lactams (lactams having 3 or more ring members), amino acids, or polyamides obtained by polymerizing or copolymerizing a nylon salt obtained by reacting a diamine with a dicarboxylic acid. Can be mentioned.

Examples of the cyclic lactam include ε-caprolactam, ω-enantractam, ω-laurolactam, α-pyrrolidone, α-piperidone and the like.

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

Examples of the diamine forming the nylon salt include tetramethylenediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, decamethylenediamine, undecamethylenediamine, dodecamethylenediamine, 2,2. Aliphatic amines such as 4-trimethylhexamethylenediamine and 2,4,4-trimethylhexamethylenediamine;
1,3-bis (aminomethyl) cyclohexane, 1,4-bis (aminomethyl) cyclohexane, isophorone diamine, piperazine, bis (4-aminocyclohexyl) methane, 2,2-bis- (4-aminocyclohexyl) propane, etc. Alicyclic diamine;
Examples thereof include aromatic diamines such as m-xylylenediamine and paraxylylenediamine.

Examples of the dicarboxylic acid forming the nylon salt include aliphatic dicarboxylic acids such as glutaric acid, adipic acid, pimeric acid, suberic acid, azelaic acid, sepatic acid, undecandionic acid, and dodecandionic acid;
Hexahydroterephthalic acid, and alicyclic carboxylic acids such as hexahydroisophthalic acid;
Telephthalic 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- Examples thereof include aromatic dicarboxylic acids such as naphthalenedicarboxylic acid, 1,8-naphthalenedicarboxylic acid, 2,3-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid and 2,7-naphthalenedicarboxylic acid.

More specifically, as the polyamide, 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, Copolymer of 6-Nylon and 66-Nylon (Nylon 6/66), Copolymer of 6-Nylon and 610-Nylon, 6-Nylon and 611-Nylon Copolymer, Copolymer of 6-Nylon and 12-Nylon (Nylon 6/12), Copolymer of 6-Nylon and 612 Nylon, Copolymer of 6-Nylon and 6T-Nylon, Copolymer of 6-Nylon and 6I-Nylon , 6-Nylon, 66-Nylon and 610-Nylon Copolymer, 6-Nylon, 66-Nylon and 12-Nylon Copolymer (Nylon 6/66/12), 6-Nylon, 66-Nylon and 612-Nylon Copolymer with, 66-Nylon and 6T-Nylon, 66-Nylon and 6I-Nylon, 6T-Nylon and 6I-Nylon, 66-Nylon, 6T-Nylon and 6I-Nylon Examples include copolymers.

The polyamide is 6-nylon, 12-nylon, 66-nylon, nylon 6/66, nylon 6/12 or nylon 6/66/12 in terms of heat resistance, mechanical strength, availability, and the like. Is preferable.

The polyamide contained in the intermediate layer 13 may be a biomass-derived polyamide. By using the biomass-derived polyamide in the transparent multilayer film 1, the amount of petroleum resources used can be reduced, and the amount of carbon dioxide emitted during the production and disposal of the transparent multilayer film 1 can be reduced. That is, such a transparent multilayer film 1 has a remarkable effect in that the environmental load can be reduced. The transparent multilayer film 1 in which the intermediate layer 13 contains a biomass-derived polyamide as the polyamide is a preferable example.

Examples of the biomass-derived polyamide include plant-derived polyamides such as carbon-neutral sugar cane.
Further, as the biomass-derived polyamide, for example, 6-nylon, 11-nylon, 12-nylon, 66-nylon, nylon 6/66, nylon 6/12, nylon 6/66/12, etc. Examples of all raw material monomers include those using biomass-derived monomers. As an example of such a biomass-derived polyamide, more specifically, vegetable 11-nylon, which is a condensed polymer of 11-aminoundecanoic acid obtained from castor oil, which is a vegetable oil, can be mentioned.

When the intermediate layer 13 contains the above-mentioned biomass-derived polyamide, it may contain only the biomass-derived polyamide as the polyamide, or both the biomass-derived polyamide and the non-biomass-derived polyamide. You may.

When the intermediate layer 13 contains the above-mentioned polyamide, the content of the biomass-derived polyamide in the intermediate layer 13 relative to the total content of the polyamide (the total content of the non-biomass-derived polyamide and the biomass-derived polyamide). The ratio may be, for example, 3% by mass or more, 20% by mass or more, 50% by mass or more, 70% by mass or more, and 90% by mass or more, and even 100% by mass, that is, the intermediate layer. The polyamide contained in 13 may be all biomass-derived polyamide. The higher the ratio, the higher the effect of reducing the environmental load on the transparent multilayer film 1.

The nitrogen-containing resin contained in the intermediate layer 13 may be only one type, may be two or more types, and when there are two or more types, the combination and ratio thereof are arbitrary depending on the purpose. Can be selected.

The intermediate layer 13 may contain other components in addition to the nitrogen-containing resin as long as the effect is not impaired.
The other components contained in the intermediate layer 13 may be only one kind, two or more kinds, and when there are two or more kinds, the combination and ratio thereof are arbitrary depending on the purpose. Can be selected.

In the intermediate layer 13, the ratio of the content of the nitrogen-containing resin to the total mass of the intermediate layer 13 is preferably 50 to 100% by mass, more preferably 70 to 100% by mass. When the ratio is at least the lower limit value, the effect obtained by the transparent multilayer film 1 including the intermediate layer 13 becomes higher.
The ratio is usually the same as the ratio of the content of the nitrogen-containing resin (parts by mass) to the total content (parts by mass) of the components that do not vaporize at room temperature in the composition for forming an intermediate layer described later.

Examples of the other components contained in the intermediate layer 13 include antioxidants and the like.

The intermediate layer 13 may be composed of one layer (single layer) or may be composed of a plurality of layers of two or more layers. When the intermediate layer 13 is composed of a plurality of layers, the plurality of layers may be the same or different from each other, and the combination of the plurality of layers is not particularly limited as long as the effects of the present invention are not impaired.

The ratio of the thickness of the intermediate layer 13 to the thickness of the transparent multilayer film 1 is preferably 8 to 18%, more preferably 11 to 15%. When the ratio is at least the lower limit value, the effect obtained by the transparent multilayer film 1 including the intermediate layer 13 becomes higher. When the ratio is not more than the upper limit value, it is possible to avoid an excessive thickness.
The thickness of the intermediate layer 13 may be, for example, 4 to 9 μm.

When the intermediate layer 13 is composed of a plurality of layers, the total thickness of the plurality of layers may satisfy the condition of the preferable ratio of the thickness of the intermediate layer 13 to be the thickness.

<Oxygen barrier layer>
The oxygen barrier layer 14 has transparency.

The oxygen barrier layer 14 is preferably a resin layer containing an oxygen barrier resin having an oxygen barrier property.

Examples of the oxygen barrier resin include ethylene-vinyl alcohol copolymer (also known as ethylene-vinyl acetate copolymer saponified product, EVOH), polyamide, polyvinyl alcohol, and polyacrylonitrile.
Among these, the oxygen barrier layer 14 preferably contains an ethylene-vinyl alcohol copolymer, and has an ethylene copolymerization ratio (in other words, in the ethylene-vinyl alcohol copolymer in the ethylene-vinyl alcohol copolymer). It is more preferable to contain an ethylene-vinyl alcohol copolymer in which the ratio of the amount of the structural unit derived from ethylene to the total amount of the structural unit of the above is 30 to 50 mol%.

The oxygen barrier layer 14 contains only one type of component exhibiting oxygen barrier properties (for example, the oxygen barrier resin), two or more types, or two or more types. , Their combinations and ratios can be arbitrarily selected according to the purpose.

The oxygen barrier layer 14 may contain other components in addition to the component exhibiting the oxygen barrier property (for example, the oxygen barrier resin) as long as the oxygen barrier property is not impaired.
The other components contained in the oxygen barrier layer 14 may be only one type, may be two or more types, and when there are two or more types, the combination and ratio thereof may be determined according to the purpose. It can be selected arbitrarily.

In the oxygen barrier layer 14, the ratio of the content of the component exhibiting the oxygen barrier property to the total mass of the oxygen barrier layer 14 (for example, the ratio of the content of the oxygen barrier resin) is 50 to 100% by mass. Is preferable, and 70 to 100% by mass is more preferable. When the ratio is equal to or higher than the lower limit value, the oxygen barrier property of the oxygen barrier layer 14 becomes higher.
The ratio is usually the ratio of the content (parts by mass) of the component exhibiting oxygen barrier properties to the total content (parts by mass) of the components that do not vaporize at room temperature in the composition for forming an oxygen barrier layer described later. It is the same.

Examples of the other components contained in the oxygen barrier layer 14 include antioxidants and the like.

The oxygen barrier layer 14 may be composed of one layer (single layer) or may be composed of two or more layers. When the oxygen barrier layer 14 is composed of a plurality of layers, the plurality of layers may be the same or different from each other, and the combination of the plurality of layers is not particularly limited as long as the effects of the present invention are not impaired.

The ratio of the thickness of the oxygen barrier layer 14 to the thickness of the transparent multilayer film 1 is preferably 5 to 15%, more preferably 8 to 12%. When the ratio is at least the lower limit value, the oxygen barrier property of the oxygen barrier layer 14, in other words, the oxygen barrier property of the transparent multilayer film 1 is further improved. When the ratio is not more than the upper limit value, the oxygen barrier layer 14 maintains a good oxygen barrier property and is highly effective in suppressing deterioration of appearance such as foaming at the time of film formation.
The thickness of the oxygen barrier layer 14 may be, for example, 2.5 to 7.5 μm.

When the oxygen barrier layer 14 is composed of a plurality of layers, the total thickness of the plurality of layers may satisfy the condition of the preferable ratio of the thickness of the oxygen barrier layer 14 to be the thickness.

^{The oxygen gas permeation amount of the oxygen barrier layer 14 is preferably 50 cc / m 2} · atm · day or less in an atmosphere of, for example, 20 ° C. and 80% RH (relative humidity).
The oxygen gas permeation amount of the oxygen barrier layer 14 can be measured according to, for example, JIS K 7126-2.

<Outermost layer>
The outermost surface layer 15 is provided on the transparent multilayer film 1 on the side opposite to the intermediate layer 13 side of the oxygen barrier layer 14.
The outermost layer 15 is the other outermost layer of the transparent multilayer film 1, and is arranged on the outermost side of the other side opposite to the easy peel layer 11 in the stacking direction of each layer constituting the transparent multilayer film 1. .. That is, the surface of the outermost layer 15 opposite to the oxygen barrier layer 14 side (sometimes referred to as the "second surface" in the present specification) 15b is an exposed surface in the transparent multilayer film 1.
The outermost layer 15 has transparency.

The outermost layer 15 is a layer for protecting other layers constituting the transparent multilayer film 1, and by appropriately selecting the constituent material, the outermost layer 15 is further combined with a layer that imparts new properties to the transparent multilayer film 1. It is possible to do.

The outermost surface layer 15 is preferably a resin layer containing a resin.

Examples of the resin which is a constituent material of the outermost layer 15 include a nitrogen-containing resin and polyester.

Examples of the nitrogen-containing resin which is a constituent material of the outermost layer 15 include the same nitrogen-containing resin as the above-mentioned nitrogen-containing resin as a constituent material of the intermediate layer 13.
For example, among the nitrogen-containing resins, examples of polyamide include 6-nylon, 11-nylon, 12-nylon, 66-nylon, nylon 6/66, nylon 6/12, nylon 6/66/12, and the like. Be done.

The polyamide, which is a constituent material of the outermost layer 15, may be a biomass-derived polyamide. By using the biomass-derived polyamide in the transparent multilayer film 1, the amount of petroleum resources used can be reduced, and the amount of carbon dioxide emitted during the production and disposal of the transparent multilayer film 1 can be reduced. That is, such a transparent multilayer film 1 has a remarkable effect in that the environmental load can be reduced.

Examples of the biomass-derived polyamide include plant-derived polyamides such as carbon-neutral sugar cane.
Further, as the biomass-derived polyamide, for example, 6-nylon, 11-nylon, 12-nylon, 66-nylon, nylon 6/66, nylon 6/12, nylon 6/66/12, etc. Examples of all raw material monomers include those using biomass-derived monomers. As an example of such a biomass-derived polyamide, more specifically, vegetable 11-nylon, which is a condensed polymer of 11-aminoundecanoic acid obtained from castor oil, which is a vegetable oil, can be mentioned.

When the outermost layer 15 contains the above-mentioned biomass-derived polyamide, the polyamide may contain only the biomass-derived polyamide, or both the biomass-derived polyamide and the non-biomass-derived polyamide. You may.

When the outermost layer 15 contains the above-mentioned polyamide, the content of the biomass-derived polyamide in the outermost layer 15 with respect to the total content of the polyamide (the total content of the non-biomass-derived polyamide and the biomass-derived polyamide). The ratio may be, for example, 3% by mass or more, 20% by mass or more, 50% by mass or more, 70% by mass or more, and 90% by mass or more, and even if it is 100% by mass, that is, the outermost layer. The polyamide contained in 15 may be all biomass-derived polyamide. The higher the ratio, the higher the effect of reducing the environmental load on the transparent multilayer film 1.

Examples of the polyester which is a constituent material of the outermost layer 15 include polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polytrimethylene terephthalate (PTT), polyethylene naphthalate (PEN), and polybutylene terephthalate (PBN). And so on.

The polyester which is a constituent material of the outermost layer 15 may be a biomass-derived polyester. By using the biomass-derived polyester in the transparent multilayer film 1, the amount of petroleum resources used can be reduced, and the amount of carbon dioxide emitted during the production and disposal of the transparent multilayer film 1 can be reduced. That is, such a transparent multilayer film 1 has a remarkable effect in that the environmental load can be reduced.

Examples of the biomass-derived polyester include plant-derived polyesters such as carbon-neutral sugar cane.
Examples of the biomass-derived polyester include polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polytrimethylene terephthalate (PTT), polyethylene naphthalate (PEN), polybutylene naphthalate (PBN), and the like. Examples thereof include those using biomass-derived monomers as some or all of the raw material monomers.

When the outermost layer 15 contains the biomass-derived polyester, the polyester may contain only the biomass-derived polyester, or both the biomass-derived polyester and the non-biomass-derived polyester. You may.

When the outermost layer 15 contains the polyester, the content of the polyester derived from biomass in the outermost layer 15 with respect to the total content of the polyester (the total content of the polyester not derived from biomass and the polyester derived from biomass). The ratio may be, for example, 3% by mass or more, 20% by mass or more, 50% by mass or more, 70% by mass or more, and 90% by mass or more, and even if it is 100% by mass, that is, the outermost layer. The polyester contained in 15 may be all biomass-derived polyester. The higher the ratio, the higher the effect of reducing the environmental load on the transparent multilayer film 1.

The transparent multilayer film 1 in which the outermost layer 15 contains a biomass-derived polyamide or a biomass-derived polyester as the polyamide or polyester is a preferable example.

When the oxygen barrier layer 14 is the outermost layer of the transparent multilayer film 1, it may easily absorb moisture during storage. When the oxygen barrier layer 14 absorbs moisture, its Young's modulus decreases, so that tarmi is generated in the entire transparent multilayer film 1. On the other hand, the outermost layer 15 is laminated on the oxygen barrier layer 14, and the outermost layer of the transparent multilayer film 1 is not the oxygen barrier layer 14 but the outermost layer 15, so that the moisture absorption of the oxygen barrier layer 14 is suppressed. .. In particular, the outermost layer 15 containing the nitrogen-containing resin has a high effect of suppressing moisture absorption. In this way, the outermost layer 15 not only protects the other layers constituting the transparent multilayer film 1, but also can impart a new property to the transparent multilayer film 1 that the oxygen barrier layer 14 does not easily absorb moisture. Is.

The resin contained in the outermost layer 15 may be only one type, may be two or more types, and when there are two or more types, the combination and ratio thereof may be arbitrarily selected according to the purpose. can.

The outermost layer 15 preferably contains the nitrogen-containing resin or polyester as the resin, and more preferably contains polyamide or polyester.

The outermost layer 15 may contain other components (in other words, non-resin components) in addition to the resin as long as the characteristics are not impaired.
The other component contained in the outermost layer 15 may be only one kind, two or more kinds, and when there are two or more kinds, the combination and ratio thereof are arbitrary depending on the purpose. Can be selected.

In the outermost layer 15, the ratio of the content of the resin to the total mass of the outermost layer 15 is preferably 50 to 100% by mass, more preferably 70 to 100% by mass. When the ratio is equal to or higher than the lower limit value, the characteristics of the outermost layer 15 become higher.
The ratio is usually the same as the ratio of the content (parts by mass) of the resin to the total content (parts by mass) of the components that do not vaporize at room temperature in the composition for forming the outermost layer, which will be described later.

Examples of the other component contained in the outermost layer 15 include silica, an antioxidant, and a slip agent (for example, erucic acid amide). Among them, it is preferable that the outermost layer 15 contains silica from the viewpoint of adjusting the coefficient of dynamic friction between the easy peel layer 11 and the outermost layer 15.

When the outermost layer 15 contains silica, the content of silica in the outermost layer 15 is preferably 50 to 27,000 ppm, more preferably 70 to 24,000 ppm, and even more preferably 90 to 21,000 ppm. ..

The outermost surface layer 15 may be composed of one layer (single layer) or may be composed of a plurality of layers of two or more layers. When the outermost surface layer 15 is composed of a plurality of layers, the plurality of layers may be the same or different from each other, and the combination of the plurality of layers is not particularly limited as long as the effects of the present invention are not impaired.

The ratio of the thickness of the outermost layer 15 to the thickness of the transparent multilayer film 1 is preferably 20 to 40%, more preferably 25 to 35%. When the ratio is equal to or higher than the lower limit value, the characteristics of the outermost layer 15 are further improved. When the ratio is not more than the upper limit value, it is possible to avoid an excessive thickness.

The thickness of the outermost layer 15 is 20 μm or less.
By setting the thickness of the outermost layer 15 to 20 μm or less, it can be extruded stably at the time of manufacturing.

The thickness of the outermost layer 15 is preferably 10 to 20 μm, more preferably 12 to 18 μm, and even more preferably 14 to 16 μm.
By setting the thickness of the outermost layer 15 within the above range, the effect of stable extrusion during manufacturing can be further improved.

When the outermost layer 15 is composed of a plurality of layers, the total thickness of the plurality of layers may satisfy the condition of the preferable ratio of the thickness of the outermost layer 15 to be the thickness.

<Adhesive layer>
The adhesive layer 19 adheres the water vapor barrier layer 12 and the intermediate layer 13 adjacent thereto.
The adhesive layer 19 has transparency.
The adhesive layer 19 is an arbitrary component and can be omitted in the transparent multilayer film 1. However, the provision of the adhesive layer 19 further stabilizes the multilayer structure of the transparent multilayer film 1.

The adhesive layer 19 is preferably a resin layer containing an adhesive resin.

Examples of the adhesive resin include polyolefin resins and the like.
The polyolefin-based resin is a resin having a structural unit derived from an olefin, and may be a modified polyolefin such as an acid-modified polyolefin having an acidic group.
Examples of the polyolefin-based resin include ethylene-based copolymers, propylene-based copolymers, butene-based copolymers, and modified products of these copolymers (in other words, modified copolymers). The polyolefin-based resin is preferably a random copolymer, a graft copolymer, or a block copolymer from the viewpoint of further improving the adhesiveness.

Examples of the ethylene-based copolymer contained in the adhesive layer 19 include the ethylene-based copolymer described above as a component contained in the easy peel layer 11, and a modified product (modified copolymer) thereof.
Examples of the propylene-based copolymer contained in the adhesive layer 19 include a copolymer of propylene and a vinyl group-containing monomer, a modified product thereof (modified copolymer), and the like. More specific examples of such a propylene-based copolymer include maleic anhydride graft-modified linear low-density polypropylene and propylene-based thermoplastic elastomer.
Examples of the butene-based copolymer contained in the adhesive layer 19 include a copolymer of 1-butene and a vinyl group-containing monomer, a copolymer of 2-butene and a vinyl group-containing monomer, and these copolymers. Modified products (modified copolymers) and the like can be mentioned.

The adhesive layer 19 contains only one type of component (for example, the adhesive resin) that exhibits adhesiveness, may be two or more types, and if there are two or more types, they may be used. The combination and ratio of the above can be arbitrarily selected according to the purpose.

The adhesive layer 19 may contain other components in addition to the component exhibiting adhesiveness (for example, the adhesive resin) as long as the adhesiveness is not impaired.
The other components contained in the adhesive layer 19 may be only one type, two or more types, and when two or more types, the combination and ratio thereof are arbitrary depending on the purpose. Can be selected.

In the adhesive layer 19, the ratio of the content of the component exhibiting adhesiveness to the total mass of the adhesive layer 19 (for example, the ratio of the content of the adhesive resin) is preferably 80 to 100% by mass. More preferably, it is 90 to 100% by mass. When the ratio is equal to or higher than the lower limit value, the adhesiveness of the adhesive layer 19 becomes higher.
The ratio is usually the same as the ratio of the content (parts by mass) of the component exhibiting adhesiveness to the total content (parts by mass) of the components that do not vaporize at room temperature in the composition for forming an adhesive layer described later. be.

Examples of the other components contained in the adhesive layer 19 include antioxidants and the like.

The adhesive layer 19 may be composed of one layer (single layer) or may be composed of two or more layers. When the adhesive layer 19 is composed of a plurality of layers, the plurality of layers may be the same or different from each other, and the combination of the plurality of layers is not particularly limited as long as the effects of the present invention are not impaired.

The ratio of the thickness of the adhesive layer 19 to the thickness of the transparent multilayer film 1 is preferably 7 to 17%, more preferably 10 to 14%. When the ratio is equal to or higher than the lower limit value, the adhesive layer 19 has better adhesiveness. When the ratio is equal to or less than the upper limit value, excessive thickness is suppressed.
The thickness of the adhesive layer 19 may be, for example, 3.5 to 8.5 μm.

When the adhesive layer 19 is composed of a plurality of layers, the total thickness of the plurality of layers may satisfy the condition of the preferable ratio of the thickness of the adhesive layer 19 to be the thickness.

The haze of the transparent multilayer film 1 is preferably 14% or less, more preferably 12% or less.
The lower limit of the haze of the transparent multilayer film 1 is not particularly limited. For example, the haze may be 0.5% or more in that the transparent multilayer film 1 can be easily manufactured.
However, the haze of the transparent multilayer film 1 shown here is an example.

The haze of the transparent multilayer film 1 can be adjusted by adjusting the type or content of the components contained in each of the above-mentioned layers constituting the haze. For example, the haze can be more easily adjusted by adjusting the presence or absence of the above-mentioned anti-fog agent or crystallization nucleating agent in each layer, the amount used when used, and the like.

In the present specification, the “film haze” means a film measured in accordance with JIS K 7136: 2000.

The thickness of the transparent multilayer film 1 is not particularly limited, but is preferably 35 to 70 μm.

The transparent multilayer film of the present embodiment is not limited to the above-described embodiment, and a part of the structure may be changed, deleted or added without departing from the spirit of the present invention.

For example, the transparent multilayer film 1 shown in FIG. 1 includes an easy peel layer 11, a water vapor barrier layer 12, an intermediate layer 13, an oxygen barrier layer 14, an outermost layer 15, and an adhesive layer 19. , Other layers that do not fall under any of these may be further provided.
The other layer is not particularly limited and may be arbitrarily selected depending on the intended purpose.

For example, the transparent multilayer film 1 may be provided with another adhesive layer similar to the adhesive layer 19 between the other two layers other than between the water vapor barrier layer 12 and the intermediate layer 13. Examples of the other adhesive layer include those provided between the oxygen barrier layer 14 and the outermost layer 15, which is an example of the other adhesive layer.

<< Manufacturing method of transparent multilayer film >>
The transparent multilayer film is produced by, for example, a feed block method in which a resin or a resin composition used as a material for forming each layer is melt-extruded using several extruders, a coextrusion T-die method such as a multi-manifold method, or air cooling. It can be manufactured by a formula or water-cooled coextrusion inflation method or the like.

Further, in the transparent multilayer film, a resin or a resin composition serving as a material for forming any of the layers thereof is coated on the surface of another layer for forming the transparent multilayer film, if necessary. It can also be produced by forming a laminated structure in the transparent multilayer film by drying and, if necessary, further laminating layers other than these so as to have a desired arrangement form.

Further, as for the transparent multilayer film, two or more films for forming any two or more layers are separately prepared in advance, and these films are prepared by a dry laminating method or an extrusion laminating method using an adhesive. It can also be manufactured by laminating by laminating by either a hot melt laminating method or a wet laminating method, and if necessary, further laminating layers other than these so as to have a desired arrangement form. At this time, as the adhesive, an adhesive capable of forming the adhesive layer may be used.

Further, the transparent multilayer film is required by laminating two or more films separately prepared in advance by a thermal (heat) laminating method or the like without using an adhesive. Depending on the situation, it can also be manufactured by further laminating layers other than these so as to have a desired arrangement form.

When producing the transparent multilayer film, two or more methods for forming any layer (in other words, a film) in the transparent multilayer film described above may be combined.

The resin composition used as a material for forming any of the layers in the transparent multilayer film adjusts the type and content of the contained components so that the formed layer contains the desired component at the desired content. Then, it may be manufactured. For example, the ratio of the contents of the components that do not vaporize at room temperature in the resin composition is usually the same as the ratio of the contents of the components in the layer formed from the resin composition.

A resin composition for forming an easy peel layer (in the transparent multilayer film 1 shown in FIG. 1, the easy peel layer 11) (in the present specification, it may be referred to as a "composition for forming an easy peel layer"). Examples thereof include those containing the polypropylene-based resin and other components. Examples of the other component in the easy peel layer include the anti-fog agent, anti-blocking agent, antistatic agent and the like.

A resin composition for forming a water vapor barrier layer (in the transparent multilayer film 1 shown in FIG. 1, the water vapor barrier layer 12) (in the present specification, it may be referred to as a "water vapor barrier layer forming composition"). Examples thereof include those containing a component exhibiting a water vapor barrier property (for example, the water vapor barrier resin) and other components. Examples of the other components in the composition for forming a water vapor barrier layer include the crystallization nucleating agent and the anti-fog agent.

As a resin composition for forming an intermediate layer (intermediate layer 13 in the transparent multilayer film 1 shown in FIG. 1) (in the present specification, it may be referred to as a “composition for forming an intermediate layer”). For example, those containing the nitrogen-containing resin and other components may be mentioned. Examples of the other components in the composition for forming an intermediate layer include antioxidants and the like.

A resin composition for forming an oxygen barrier layer (in the transparent multilayer film 1 shown in FIG. 1, the oxygen barrier layer 14) (in the present specification, it may be referred to as an "oxygen barrier layer forming composition"). Examples thereof include those containing a component exhibiting oxygen barrier properties (for example, the oxygen barrier resin) and other components. Examples of the other components in the composition for forming an oxygen barrier layer include antioxidants and the like.

As a resin composition for forming the outermost layer (the outermost layer 15 in the transparent multilayer film 1 shown in FIG. 1) (in the present specification, it may be referred to as a "composition for forming the outermost layer"). For example, those containing the resin and other components other than the above can be mentioned. Examples of the other components in the composition for forming the outermost layer include antioxidants and the like.

As a resin composition for forming an adhesive layer (adhesive layer 19 in the transparent multilayer film 1 shown in FIG. 1) (in the present specification, it may be referred to as an "adhesive layer forming composition"). For example, those containing a component exhibiting adhesiveness (for example, the adhesive resin) and other components other than that may be mentioned. Examples of the other components in the composition for forming an adhesive layer include antioxidants and the like.

<< Packaging >>
The package according to one embodiment of the present invention includes the transparent multilayer film.
The transparent multilayer film can be formed into various packages by sealing the transparent multilayer film with another resin film, a resin sheet or a resin tray (in other words, a resin bottom material) by the easy peel layer in the transparent multilayer film.

The preferred packaging body includes, for example, a lid material and a bottom material, the lid material is made of the transparent multilayer film, and the bottom material is made of a resin formed by deep drawing, and the lid material (the transparent material). An example is a multi-layer film) in which an easy peel layer is sealed with a bottom material (deep squeezed package).
The preferred packaging body includes, for example, a lid material and a tray, the lid material is made of the transparent multilayer film, the tray is made of resin, and the easy peel in the lid material (the transparent multilayer film). An example is a package in which a layer is sealed with a tray (a package having a tray).
As the preferred package, for example, a soft gas pack in which the transparent multilayer film is sealed with the same type of transparent multilayer film or a different type of film or sheet by an easy peel layer therein. Can be mentioned.

FIG. 2 is a cross-sectional view schematically showing an example of the package of the present embodiment.
In the drawings after FIG. 2, the same components as those shown in the already explained figures are designated by the same reference numerals as in the case of the already explained figures, and detailed description thereof will be omitted.

The package 101 shown here includes a lid material 10 and a bottom material 8.
The lid material 10 is the transparent multilayer film according to the above-described embodiment of the present invention. For example, the transparent multilayer film 1 shown in FIG. 1 can be used as the lid material 10.
The bottom material 8 is obtained by deep drawing a resin film (deep drawing molded body). That is, the package 101 is a deep-drawn package.
In addition, in the lid material 10 in FIG. 2, the distinction between each layer in the multilayer film constituting the lid material 10 is omitted.

A recess 80 is formed in the bottom material 8.
One surface of the area of the bottom material 8 excluding the recess 80 (sometimes referred to as the "first surface" in the present specification) 8a and one surface of the lid material 10 (in the present specification, the "first surface"). The 10a (sometimes referred to as "one surface") is a sealing surface and faces each other. When the lid material 10 is the transparent multilayer film 1, the first surface 10a of the lid material 10 is the first surface 11a of the easy peel layer 11.

The package 101 is composed of a seal of the lid material 10 and the bottom material 8. More specifically, the first surface 8a of the region excluding the recess 80 of the bottom material 8 and the first surface 10a of the lid material 10 are overlapped and sealed with each other in a region near their peripheral edges. As a result, in the region of the recess 80 of the bottom material 8, the storage portion 101a is formed between the first surface 8a of the bottom material 8 and the first surface 10a of the lid material 10. Then, the stored object 9 is stored in the storage portion 101a.
When the lid material 10 is the transparent multilayer film 1, the other surface of the lid material 10 (sometimes referred to as the "second surface" in the present specification) 10b is the second surface 5b of the outermost layer 15. ..

In FIG. 3, in the storage portion 101a of the package 101, some gaps are seen between the stored object 9 and the bottom material 108, and between the stored object 9 and the lid material 10. The presence of a gap is not essential in the package 101 in which the stored object 9 is stored.

The thickness of the lid material 10 in the flat portion is the same as the thickness of the multilayer film 1 described above.

Examples of the bottom material 8 include those made of a single-layer or multi-layer resin film that can be used in a normal deep-drawn package.
The thickness of the bottom material 8 in the flat portion thereof is preferably 300 to 500 μm.

The stored items 9 can be arbitrarily selected depending on the intended purpose, and examples of the stored items 9 include foods.
That is, the package 101 is suitable as a package for food, and is particularly suitable as a package for cooking in a microwave oven. It is also suitable as a packaging material for cosmetics, pharmaceuticals, etc. (eye masks, etc.) that require heating in a microwave oven.

In the package 101, the stored object 9 in the storage portion 101a can be clearly seen through the lid material 10.

When the package 101 is opened, the lid material 10 is peeled off from the bottom material 8, so that the easy peel layer 11 and the bottom material 8 in the lid material 10 are easily peeled off.

<< Manufacturing method of packaging >>
The package can be manufactured by using the transparent multilayer film and heat-sealing the transparent multilayer film and the object to be sealed so as to form a storage portion for storing the object to be packaged. Examples of the object to be sealed include the above-mentioned bottom material, tray, other resin film, resin sheet and the like.

The bottom material can be produced, for example, by deep drawing a resin film by a known method.
The tray can be produced, for example, by molding a flat resin sheet into a desired shape by a known method.

When the transparent multilayer film and the object to be sealed are heat-sealed, the sealing temperature may be, for example, 150 to 180 ° C., and the sealing time may be, for example, 0.5 to 3.0 seconds. The sealing pressure may be, for example, ² to 8 kgf / cm 2.

When the transparent multilayer film is used as a lid material and the bottom material is used to manufacture a deeply drawn package, for example, a long bottom material in which recesses for forming a storage portion are arranged in the longitudinal direction. And a long lid material, while applying a tension of a specific value or more to this long lid material, and further filling the area forming the storage portion with the inert gas and the object to be packaged. The long lid material and the long bottom material are sequentially heat-sealed in these longitudinal directions, and after the completion of all the heat seals, the lid material and the bottom material are cut for each of the formed storage portions. , The desired deeply squeezed package is obtained. In this manufacturing method, the cutting of the lid material and the bottom material is not performed immediately after the completion of the individual heat seals (in other words, after the formation of the individual storage portions), so that all the heat seals are completed (in other words). Then, tension continues to be applied to the heat-sealed long lid material until the lid material and the bottom material are started to be cut). Further, during this period, the storage portion is filled with the inert gas, so that the internal pressure is high. Therefore, when a conventional lid material is used, the long lid material that is heat-sealed is easily peeled off from the bottom material due to the influence of these tensions and internal pressure, and the lid material and the bottom material are in a state of being easily peeled off. The area of the part where the seal is maintained between them becomes small, and in the worst case, a gap is created between the lid material and the bottom material. In particular, in the peripheral portion of the bottom material, which will eventually become a corner portion, the lid material is likely to be peeled off from the bottom material. On the other hand, when a long lid material made of the transparent multilayer film of the present embodiment is used, such peeling of the lid material from the bottom material in the manufacturing process of the package is suppressed.
As described above, the transparent multilayer film of the present embodiment has a particularly remarkable effect when used in the production of a deep-drawn package.

On the other hand, when the transparent multilayer film is used as a lid material and a tray is used to manufacture a package having the tray, the tray and the long lid material are sequentially heat-sealed for each tray and heated. Since the lid material is cut for each tray immediately after sealing, tension is not continuously applied to the heat-sealed lid material. The long lid material made of the transparent multilayer film of the present embodiment can also be used for producing such a package having a tray, and the package can be produced more stably.

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

<Polyolefin-based copolymer (I)>
The polyolefin-based copolymer (I) used in each Example and Comparative Example is shown below.
Polyolefin-based copolymer (I): R ¹ is a hydrogen atom and R ² is an ethyl group.

[Example 1]
<< Manufacturing of transparent multilayer film >>
<Manufacturing of composition for forming easy peel layer>
Low-density polyethylene (LDPE, "F522N" manufactured by Ube Maruzen Polyethylene) (20 parts by mass), polypropylene random copolymer (rPP, "S131" manufactured by Sumitomo Chemical Co., Ltd.) (45 parts by mass), and antifogging agent master batch (Takemoto) "P302AB" manufactured by Yushi Co., Ltd., the content of the fatty acid ester compound as an antifogging agent is 10% by mass, the content of the polypropylene resin is 90% by mass) (30 parts by mass), and the polyolefin-based copolymer (I) ( 5 parts by mass) and kneaded at room temperature to obtain a composition for forming an easy peel layer.

<Manufacturing of composition for forming water vapor barrier layer>
Homopolypropylene (hPP, Sumitomo Chemical Co., Ltd. "WF836DG3") (82 parts by mass), crystallization nucleating agent master batch (Tokyo Ink Co., Ltd. "PPM-NAT94", sorbitol-based crystallization nucleating agent content of 10% by mass) , Polypropylene resin content 90% by mass) (3 parts by mass), antifogging agent master batch ("P302AB" manufactured by Takemoto Oil & Fat Co., Ltd., content of fatty acid ester compound as antifogging agent 10% by mass, polypropylene The content of the based resin (90% by mass) (5 parts by mass) was kneaded at room temperature to obtain a composition for forming a steam barrier layer.

<Manufacturing of transparent multilayer film>
Modified polypropylene (modified PP, "QE060" manufactured by Mitsui Kagaku Co., Ltd.) is prepared as the resin (adhesive resin) constituting the adhesive layer, and 6-nylon (Ny6, manufactured by Ube Kosan Co., Ltd.) is used as the resin constituting the intermediate layer. 1030B2 ”, melting point 225 ° C.), and ethylene-vinyl acetate copolymer saponified product (EVOH, Kuraray“ J171B ”, ethylene copolymer ratio 32 mol%) was prepared as the resin constituting the oxygen barrier layer. Then, as a resin constituting the outermost layer, a resin obtained by adding silica to Ny6 (hereinafter, may be abbreviated as "Ny6 / silica") was prepared. The content of silica in the outermost layer was 3000 ppm.

The temperature of the die is set to 245 to 275 ° C., and the composition for forming an easy peel layer, the composition for forming a water vapor barrier layer, the modified PP, Ny6, EVOH, and Ny6 / silica are co-extruded in this order. As a result, the easy peel layer (thickness 6 μm), the water vapor barrier layer (thickness 11.5 μm), the adhesive layer (thickness 6 μm), the intermediate layer (thickness 6.5 μm), and the oxygen barrier layer (thickness). A long transparent multilayer film (thickness 50 μm) was obtained in which the outermost layer (thickness 15 μm) and the outermost layer (thickness 15 μm) were laminated in this order in these thickness directions.

<< Manufacturing of packaging >>
<Manufacturing of bottom material>
The hPP layer (thickness 170 μm), the adhesive layer (thickness 20 μm), the EVOH layer (thickness 20 μm), the adhesive layer (thickness 20 μm), and the hPP layer (thickness 170 μm) are in this order. A long multilayer film (thickness 400 μm) was prepared, which was formed by being laminated in the thickness direction of the above.
Using a deep-drawing packaging machine (“R175” manufactured by Tokyo Food Machinery Co., Ltd.), the multilayer film is heat-molded under the conditions of a heating temperature of 140 ° C., a heating time of 4 seconds, and a molding time of 4 seconds to obtain the multilayer film. A molded body (combined body of bottom material) in which the storage portion of the object to be packaged was continuously molded in the longitudinal direction was produced.

<Manufacturing of packaging>
Next, using the transparent multilayer film obtained above as a lid material, the lid material and the bottom material obtained above are matched in their longitudinal directions, and the sealing temperature is 170 ° C. and the sealing time is 1. Heat sealing was performed for 2 seconds under the condition of a sealing pressure of 5 kgf / cm ^2. At this time, the easy peel layer in the lid material and the hPP layer in the bottom material were heat-sealed.
Then, after all the heating seals are completed, the bottom material and the lid material are cut for each of the formed storage portions to make the multilayer film a bottom material (thickness 400 μm) and the transparent multilayer film (thickness 50 μm). ) Was used as a lid material (deep squeezed package).

<< Manufacturing of transparent multilayer film and packaging >>
[Example 2]
As shown in Table 1, a transparent multilayer film and a package were produced by the same method as in Example 1 except that a resin obtained by adding 5000 ppm of silica to Ny6 was used as the outermost layer.

[Example 3]
As shown in Table 1, a transparent multilayer film and a package were produced by the same method as in Example 1 except that a resin obtained by adding 7,000 ppm of silica to Ny6 was used as the outermost layer.

[Example 4]
As shown in Table 1, a transparent multilayer film and a package were produced by the same method as in Example 1 except that a resin obtained by adding 10000 ppm of silica to Ny6 was used as the outermost layer.

[Example 5]
As shown in Table 1, a transparent multilayer film and a package were produced by the same method as in Example 1 except that a resin obtained by adding 12000 ppm of silica to Ny6 was used as the outermost layer.

[Example 6]
As shown in Table 1, a transparent multilayer film and a package were produced by the same method as in Example 1 except that a resin obtained by adding 15,000 ppm of silica to Ny6 was used as the outermost layer.

[Example 7]
As shown in Table 1, a transparent multilayer film and a package were produced by the same method as in Example 1 except that a resin obtained by adding 17,000 ppm of silica to Ny6 was used as the outermost layer.

[Example 8]
As shown in Table 2, a transparent multilayer film and a package were produced by the same method as in Example 1 except that a resin obtained by adding 20,000 ppm of silica to Ny6 was used as the outermost layer.

[Example 9]
As shown in Table 2, a transparent multilayer film and a package were produced by the same method as in Example 1 except that a resin obtained by adding 2000 ppm of silica to Ny6 was used as the outermost layer.

[Example 10]
As shown in Table 2, a transparent multilayer film and a package were produced by the same method as in Example 1 except that a resin obtained by adding 1000 ppm of silica to Ny6 was used as the outermost layer.

[Example 11]
As shown in Table 2, a transparent multilayer film and a package were produced by the same method as in Example 1 except that a resin obtained by adding 500 ppm of silica to Ny6 was used as the outermost layer.

[Example 12]
As shown in Table 2, a transparent multilayer film and a package were produced by the same method as in Example 1 except that a resin obtained by adding 300 ppm of silica to Ny6 was used as the outermost layer.

[Example 13]
As shown in Table 2, a transparent multilayer film and a package were produced by the same method as in Example 1 except that a resin obtained by adding 100 ppm of silica to Ny6 was used as the outermost layer.

[Example 14]
<< Manufacturing of transparent multilayer film >>
A composition for forming an easy peel layer and a composition for forming a water vapor barrier layer were obtained in the same manner as in Example 1.

Modified PP is prepared as the resin (adhesive resin) constituting the adhesive layer, Ny6 is prepared as the resin constituting the intermediate layer, EVOH is prepared as the resin constituting the oxygen barrier layer, and the first surface layer is prepared. Ny6 is prepared as a constituent resin, and as a resin constituting the second surface layer (outermost surface layer), a copolymer of 6-nylon and 66-nylon (copolymerization Ny6, 66, "5033X80" manufactured by Ube Kosan Co., Ltd., melting point A resin in which silica was added to (196 ° C.) (hereinafter, may be abbreviated as “copolymerization Ny6,66 / silica”) was prepared. The content of silica in the outermost layer was 5000 ppm.

The temperature of the die was set to 245 to 275 ° C., and the composition for forming the easy peel layer, the composition for forming the water vapor barrier layer, the modified PP, Ny6, EVOH, Ny6, and the copolymerized Ny6, 66 / silica were mixed. By co-extruding in this order, an easy peel layer (thickness 6 μm), a water vapor barrier layer (thickness 11.5 μm), an adhesive layer (thickness 6 μm), and an intermediate layer (thickness 6.5 μm). The oxygen barrier layer (thickness 5 μm), the first surface layer (thickness 15 μm), and the second surface layer (outermost layer) (thickness 12.5 μm) are laminated in this order in these thickness directions. A long transparent multilayer film (thickness 62.5 μm) was obtained.

<< Manufacturing of packaging >>
The package was manufactured in the same manner as in Example 1.

[Example 15]
<< Manufacturing of transparent multilayer film >>
A composition for forming an easy peel layer and a composition for forming a water vapor barrier layer were obtained in the same manner as in Example 1.

Modified PP is prepared as the resin (adhesive resin) constituting the first adhesive layer, Ny6 is prepared as the resin constituting the intermediate layer, EVOH is prepared as the resin constituting the oxygen barrier layer, and the second Modified polyethylene (modified PE, "NF536" manufactured by Mitsui Kagaku Co., Ltd.) was prepared as a resin (adhesive resin) constituting the adhesive layer, and Ny6 / silica was prepared as a resin constituting the outermost layer. The content of silica in the outermost layer was 5000 ppm.

The temperature of the die is set to 245 to 275 ° C., and the composition for forming an easy peel layer, the composition for forming a steam barrier layer, the modified PP, Ny6, EVOH, the modified PE, and Ny6 / silica are arranged in this order. By co-extruding with, an easy peel layer (thickness 6 μm), a steam barrier layer (thickness 11.5 μm), a first adhesive layer (thickness 6 μm), and an intermediate layer (thickness 6.5 μm) , The oxygen barrier layer (thickness 5 μm), the second adhesive layer (thickness 7.5 μm), and the outermost layer (thickness 12.5 μm) are laminated in this order in these thickness directions. Further, a long transparent multilayer film (thickness 55 μm) was obtained.

<< Manufacturing of packaging >>
The package was manufactured in the same manner as in Example 1.

[Example 16]
<< Manufacturing of transparent multilayer film >>
A composition for forming an easy peel layer and a composition for forming a water vapor barrier layer were obtained in the same manner as in Example 1.

Modified PP is prepared as the resin (adhesive resin) constituting the first adhesive layer, Ny6 is prepared as the resin constituting the intermediate layer, EVOH is prepared as the resin constituting the oxygen barrier layer, and the second Modified polyethylene (modified PE, "F515A" manufactured by Mitsubishi Chemical Co., Ltd.) is prepared as the resin (adhesive resin) constituting the adhesive layer, and glycol-modified polyethylene terephthalate (PETG, manufactured by SK Chemical Co., Ltd.) is prepared as the resin constituting the outermost layer. A resin (hereinafter, may be abbreviated as “PETG / silica”) in which silica is added to “S2008”, an amorphous resin) was prepared. The content of silica in the outermost layer was 5000 ppm.

The temperature of the die is set to 245 to 275 ° C., and the composition for forming an easy peel layer, the composition for forming a steam barrier layer, the modified PP, Ny6, EVOH, the modified PE, and PETG / silica are arranged in this order. By co-extruding with, an easy peel layer (thickness 6 μm), a steam barrier layer (thickness 11.5 μm), a first adhesive layer (thickness 6 μm), and an intermediate layer (thickness 6.5 μm) , The oxygen barrier layer (thickness 5 μm), the second adhesive layer (thickness 7.5 μm), and the outermost layer (thickness 12.5 μm) are laminated in this order in these thickness directions. Further, a long transparent multilayer film (thickness 55 μm) was obtained.

<< Manufacturing of packaging >>
The package was manufactured in the same manner as in Example 1.

[Example 17]
As the outermost layer, a mixture of Ny6 (90 parts by mass) and plant-derived 11-nylon ("Rilsan BESVO A FDA" manufactured by Arkema) (4 parts by mass) instead of a resin in which 3000 ppm of silica is added to Ny6. A transparent multilayer film and a package were produced by the same method as in Example 1 except that a resin containing 3000 ppm of silica was used.

[Comparative Example 1]
As shown in Table 3, a transparent multilayer film and a package were produced by the same method as in Example 1 except that Ny6 to which silica was not added was used as the outermost layer.

[Comparative Example 2]
As shown in Table 3, a transparent multilayer film and a package were produced by the same method as in Example 1 except that a resin obtained by adding 30,000 ppm of silica to Ny6 was used as the outermost layer.

[Comparative Example 3]
<< Manufacturing of transparent multilayer film >>
A composition for forming an easy peel layer and a composition for forming a water vapor barrier layer were obtained in the same manner as in Example 1.

Modified PP is prepared as the resin (adhesive resin) constituting the first adhesive layer, Ny6 is prepared as the resin constituting the intermediate layer, and ethylene-vinyl acetate copolymer Ken is prepared as the resin constituting the outermost layer. A resin (hereinafter, may be abbreviated as "EVOH / silica") in which silica is added to a compound (EVOH, "E173B" manufactured by Kuraray Co., Ltd., a copolymerization ratio of ethylene of 44 mol%) was prepared. The content of silica in the outermost layer was 5000 ppm.

The temperature of the die was set to 245 to 275 ° C., and the composition for forming an easy peel layer, the composition for forming a water vapor barrier layer, the modified PP, Ny6, and EVOH / silica were co-extruded in this order. Easy peel layer (thickness 6 μm), water vapor barrier layer (thickness 11.5 μm), first adhesive layer (thickness 6 μm), intermediate layer (thickness 6.5 μm), outermost layer (thickness 10 μm) ) And were laminated in this order in these thickness directions to obtain a long transparent multilayer film (thickness 40 μm).

<< Manufacturing of packaging >>
The package was manufactured in the same manner as in Example 1.

<< Evaluation of transparent multilayer film >>
<Calculation of hot tack strength ratio>
In each of the above Examples and Comparative Examples, a single-layer easy peel layer (thickness 6 μm), which is the same as that in the transparent multilayer film, was separately produced by an extrusion molding method, and the width was 25.4 mm. A test piece was prepared.
Using a "Model HT Hot Tuck Heat Seal Tester" manufactured by Teller Co., Ltd., the entire surface of one surface of this test piece is overlapped with one surface of a polypropylene layer (thickness 170 μm) to obtain a seal temperature. Heat sealing was performed under the conditions of 160 ° C., a sealing pressure of 0.473 N / mm ² , and a sealing time of 1.0 sec., And after 500 msec., The peel strength was measured under the conditions of a tensile speed of 33.3 mm / sec. Was adopted as S ₁₆₀ (N / 25.4 mm).

Further, the test piece was separately prepared, and the test piece was set to 170 ° C instead of 160 ° C by the same method as in the case _{of S 160 described above, S 170} (N / 25. 4 mm) was measured.
Then, the hot tack intensity ratio (S ₁₇₀ / S ₁₆₀ ) was calculated from these measured values. The results are shown in Tables 1-3.

<Evaluation of the effect of suppressing peeling of the lid material during heat sealing>
With respect to the 10 packages obtained in each of the above Examples and Comparative Examples, the presence or absence of peeling of the lid material from the bottom material was visually observed one by one. Then, the effect of suppressing the peeling of the lid material from the bottom material at the time of heating and sealing was evaluated according to the following criteria. The results are shown in the column of "Effect of suppressing peeling of lid material" in Tables 1 to 3.
A: No peeling was observed in all the packages.
B: Peeling was observed on one or more packages.

<Evaluation of stringing suppression effect when peeling the lid material>
In the 10 packages obtained in each of the above Examples and Comparative Examples, the lid material was peeled from the bottom material one by one, and the presence or absence of stringing between the peeled portions was visually confirmed. Then, the stringing suppressing effect of the lid material was evaluated according to the following criteria. The results are shown in the column of "Effect of suppressing stringing of lid material" in Tables 1 to 3.
(Evaluation criteria)
A: No stringing was observed on all packages.
B: Threading was observed on one or more packages.

<Measurement of surface resistivity of easy peel layer>
In each of the above Examples and Comparative Examples, a single-layer easy peel layer (thickness 6 μm), which is the same as that in the transparent multilayer film, was separately prepared by an extrusion molding method and used as a test piece. .. The surface resistivity (Ω / □) of this test piece was measured according to JIS C 2139-3-1: 2018. The results are shown in Tables 1-3.

<Measurement of haze of transparent multilayer film>
For the transparent multilayer films obtained in each of the above Examples and Comparative Examples, the haze (%) was measured from the outside on the easy peel layer side in accordance with JIS K 7136: 2000. The results are shown in Tables 1-3.

<Dynamic friction coefficient>
For the transparent multilayer films of the above Examples and Comparative Examples, the coefficient of dynamic friction between the easy peel layer and the outermost layer was measured according to (JISK7125).

<Reduction rate of tensile elastic modulus during moisture absorption>
_{For the transparent multilayer films of each of the above Examples and Comparative Examples, the tensile elastic modulus (E 1} [MPa]) of the outermost layer under the conditions of a temperature of 20 degrees and a humidity of 50%, and the maximum, according to (JISK7161). _{The tensile elastic modulus (E 2} [MPa]) of the outermost layer after the surface layer was allowed to absorb moisture under the conditions of a temperature of 20 ° C. and a humidity of 90% was measured.
Using the following formula, the rate of decrease in the tensile elastic modulus of the outermost layer after the outermost layer was allowed to absorb moisture under the conditions of a temperature of 20 ° C. and a humidity of 90% was determined.
E = E ₂ / E ₁

<Tarumi>
The transparent multilayer films obtained in each of the above Examples and Comparative Examples are wound in a roll shape with a tension of 100 N / m and allowed to absorb moisture under the conditions of a temperature of 20 ° C. and a humidity of 90%, and then visually check for the presence or absence of tarmi. It was observed and evaluated according to the following criteria.
A: No tarmi was found at the time of feeding.
B: Talmi was observed at the time of feeding.

<Rolling misalignment>
The transparent multilayer films obtained in each of the above Examples and Comparative Examples were wound in a roll shape with a tension of 100 N / m, and the presence or absence of winding deviation when transported for 600 km was visually observed and evaluated according to the following criteria.
A: No winding deviation of 3 cm or more was observed on the roll.
B: A winding deviation of 3 cm or more was observed on the roll.

As is clear from the above results, in the transparent multilayer films of Examples 1 to 16, the dynamic friction coefficient between the easy peel layer and the outermost layer is 0.10 or more and less than 1.0, and is the highest. After the surface layer was moistened under the conditions of a temperature of 20 ° C. and a humidity of 90%, the rate of decrease in the tensile elastic modulus of the outermost layer was 20% or more, so that no tarmi or winding deviation occurred.

The evaluation result of the transparent multilayer film of Example 17 was equivalent to the evaluation result of the transparent multilayer film of Example 1.

On the other hand, in the transparent multilayer film of Comparative Example 1, since the coefficient of dynamic friction between the easy peel layer and the outermost layer was 1.0 or more, tarmi was generated. Further, in the transparent multilayer film of Comparative Example 2, since the coefficient of kinetic friction between the easy peel layer and the outermost layer was less than 0.10, winding deviation occurred. Further, in the transparent multilayer film of Comparative Example 3, the rate of decrease in the tensile elastic modulus of the outermost layer after absorbing moisture under the conditions of a temperature of 20 ° C. and a humidity of 90% is less than 20%. Was occurring.

The present invention can be used as a packaging for cooking in a microwave oven among packaging for food.

1 ... Transparent multilayer film 11 ... Easy peel layer 11a ... First surface of easy peel layer 12 ... Water vapor barrier layer 13 ... Intermediate layer 14 ... Oxygen barrier layer 15 ... Most Surface layer 101 ・ ・ ・ Package 10 ・ ・ ・ Cover material

In order to solve the above problems, the present invention adopts the following configuration.
[1]. A transparent multilayer film comprising at least an easy peel layer and an outermost layer on the opposite side of the easy peel layer, wherein the dynamic friction coefficient between the easy peel layer and the outermost layer is 0.10. More than 1.0, the rate of decrease in the tensile elasticity of the outermost layer after absorbing moisture under the conditions of a temperature of 20 ° C. and a humidity of 90% is 20% or more, and the outermost layer has a rate of decrease of 20% or more. thickness, 20 [mu] m Ri der hereinafter the easy peel layer contains polypropylene resin, a width of 25.4 mm, a specimen of the easy-peel layer is is 6μm thick, the thickness is 170μm When the hot tack strength when the polypropylene layer is heat-sealed at a sealing temperature of 170 ° C. is S ₁₇₀ and the hot tack strength when heat-sealed at a sealing temperature of 160 ° C. is S ₁₆₀ , S ₁₇₀ / S ₁₆₀ ≧ 0. The easy peel layer, which satisfies the relationship of .7, contains an ethylene-based polymer having at least an ethylene-derived structural unit and a propylene-based polymer having at least a polypropylene-derived structural unit. A transparent multilayer film in which the easy peel layer contains an antifogging agent, and the ratio of the content of the antifogging agent to the total mass of the easy peel layer in the easy peel layer is 0.5 to 5% by mass. ..

[ 2 ]. The transparent multilayer film according to [1], wherein the outermost layer contains polyamide or polyester.
[ 3 ]. The transparent multilayer film according to [2 ], wherein the outermost layer contains a biomass-derived polyamide or a biomass-derived polyester as the polyamide or polyester.
[ 4 ]. The surface resistivity of the easy peel layer measured in accordance with JIS C 2139-3-1: 2018 is 1 × 10 ⁵ to 1 × 10 ¹⁴ Ω / □, of [1] to [ 3 ]. The transparent multilayer film according to any one of the items .
[ 5 ]. The transparent multilayer film according to any one of [1] to [4 ], wherein the thickness of the easy peel layer is less than 10 μm.
[ 6 ]. The transparent multilayer film according to any one of [1] to [5 ], wherein the transparent multilayer film further includes an intermediate layer.
[ 7 ]. The transparent multilayer film according to [6 ], wherein the intermediate layer contains a polyamide.
[ 8 ]. The transparent multilayer film according to [7 ], wherein the intermediate layer contains a biomass-derived polyamide as the polyamide.
[ 9 ]. The transparent multilayer film according to any one of [1] to [8 ], wherein the transparent multilayer film further includes an oxygen barrier layer.

[ 10 ]. The transparent multilayer film further includes a water vapor barrier layer, an intermediate layer, and an oxygen barrier layer, and the water vapor barrier layer and the intermediate layer are placed between the easy peel layer and the oxygen barrier layer. The transparent multilayer film according to any one of [1] to [ 9], which is arranged.
[ 11 ]. The transparent multilayer film according to any one of [1] to [10 ], wherein the transparent multilayer film further includes a water vapor barrier layer.
[ 12 ]. The transparent multilayer film according to [11 ], wherein the water vapor barrier layer is arranged adjacent to the easy peel layer.
[ 13 ]. The transparent multilayer film according to any one of [11 ] and [ 12 ], wherein the water vapor barrier layer contains polypropylene.
[ 14 ]. The transparent multilayer film according to any one of [11 ] to [ 13 ], wherein the water vapor barrier layer contains a crystallization nucleating agent.
[ 15 ]. The transparent multilayer film according to any one of [11 ] to [ 14 ], wherein the water vapor barrier layer has a melt tension of 0.2 g or more.
[ 16 ]. The transparent multilayer film according to any one of [11 ] to [ 15 ], wherein the water vapor barrier layer contains one kind of polypropylene or two or more kinds of polypropylenes having different melt tensions.
[ 17 ]. A packaging body comprising the transparent multilayer film according to any one of [1] to [ 16].

Claims (20)

A transparent multilayer film including at least an easy peel layer and an outermost layer on the opposite side of the easy peel layer.
The coefficient of kinetic friction between the easy peel layer and the outermost layer is 0.10 or more and less than 1.0.
After the outermost layer is allowed to absorb moisture under the conditions of a temperature of 20 ° C. and a humidity of 90%, the rate of decrease in the tensile elastic modulus of the outermost layer is 20% or more.
A transparent multilayer film having a thickness of the outermost layer of 20 μm or less. The easy peel layer contains a polypropylene-based resin and contains
The hot tack strength when the test piece of the easy peel layer having a width of 25.4 mm and a thickness of 6 μm and the polypropylene layer having a thickness of 170 μm were heat-sealed at a sealing temperature of 170 ° C. was set to S ₁₇₀ . The transparent multilayer film according to claim 1, which satisfies the relationship of S ₁₇₀ / S _{160 ≥ 0.7, where S 160} is the hot tack strength when heat-sealed at a sealing temperature of 160 ° C. The transparent multilayer film according to claim 1 or 2, wherein the outermost layer contains polyamide or polyester. The transparent multilayer film according to claim 3, wherein the outermost layer contains a biomass-derived polyamide or a biomass-derived polyester as the polyamide or polyester. Any of claims 1 to 4, wherein the surface resistivity of the easy peel layer measured in accordance with JIS C 2139-3-1: 2018 is 1 × 10 ⁵ to 1 × 10 ^{14 Ω / □.} The transparent multilayer film according to item 1. Any of claims 1 to 5, wherein the easy peel layer contains an ethylene-based polymer having at least an ethylene-derived structural unit and a propylene-based polymer having at least a propylene-derived structural unit. The transparent multilayer film according to item 1. The transparent multilayer film according to any one of claims 1 to 6, wherein the easy peel layer contains an anti-fog agent. The transparent multilayer film according to any one of claims 1 to 7, wherein the thickness of the easy peel layer is less than 10 μm. The transparent multilayer film according to any one of claims 1 to 8, wherein the transparent multilayer film further includes an intermediate layer. The transparent multilayer film according to claim 9, wherein the intermediate layer contains a polyamide. The transparent multilayer film according to claim 10, wherein the intermediate layer contains a biomass-derived polyamide as the polyamide. The transparent multilayer film according to any one of claims 1 to 11, wherein the transparent multilayer film further includes an oxygen barrier layer. The transparent multilayer film further includes a water vapor barrier layer, an intermediate layer, and an oxygen barrier layer.
The transparent multilayer film according to any one of claims 1 to 12, wherein the water vapor barrier layer and the intermediate layer are arranged between the easy peel layer and the oxygen barrier layer. The transparent multilayer film according to any one of claims 1 to 13, wherein the transparent multilayer film further includes a water vapor barrier layer. The transparent multilayer film according to claim 14, wherein the water vapor barrier layer is arranged adjacent to the easy peel layer. The transparent multilayer film according to claim 14 or 15, wherein the water vapor barrier layer contains polypropylene. The transparent multilayer film according to any one of claims 14 to 16, wherein the water vapor barrier layer contains a crystallization nucleating agent. The transparent multilayer film according to any one of claims 14 to 17, wherein the melt tension of the water vapor barrier layer is 0.2 g or more. The transparent multilayer film according to any one of claims 14 to 18, wherein the water vapor barrier layer contains one kind of polypropylene or two or more kinds of polypropylenes having different melt tensions. A package comprising the transparent multilayer film according to any one of claims 1 to 19.

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