JP7188522B1 - Laminated film and package - Google Patents

Abstract

An object of the present invention is to provide a laminated film having higher formability and higher reusability than conventional ones. A laminated film (1) includes a first resin layer (11) and a second resin layer (12), and the first resin layer (11) and the second resin layer (12) contain the same kind of polyolefin resin. Laminated film 1 having an elastic modulus EF′(110) of 1.5×10 7 Pa or less at 110° C. at a vibration frequency of 1 Hz when subjected to dynamic viscoelasticity measurement. [Selection drawing] Fig. 1

Description

The present invention relates to laminated films and packages.

Laminated films configured by laminating a plurality of resin layers are widely used as materials for packages. A typical laminated film includes at least a sealant layer provided for heat sealing with an object to be sealed, and an outer layer provided on the side opposite to the sealant layer side.

On the other hand, such laminated films for packaging are produced and consumed in large quantities all over the world every day because of their high convenience, and a large amount of waste is generated after use. The generation of waste has become an important issue that needs to be resolved from the perspective of improving the global environment. is being considered.

For example, if the main constituent materials of a plurality of resin layers in a laminated film are of the same type, there is no need to separate and reuse each resin layer, and the laminated film as a whole can be easily reused. , the usefulness increases.
As such a laminate film, for example, a polyethylene laminate for packaging material is disclosed, which comprises at least an oriented polyethylene film, an adhesive layer, and a heat-sealable polyethylene layer, the adhesive layer containing a non-solvent adhesive. (see Patent Document 1).

JP 2019-189333 A

However, the polyethylene laminate for packaging material disclosed in Patent Document 1 has a problem that the moldability is not necessarily sufficient. BACKGROUND ART In order to package various objects such as food, a laminated film may be formed in consideration of the shape of the object (to be stored) to form a space for storing the object to be stored. However, it is difficult to mold into a desired shape, and laminated films with insufficient moldability have limited applications.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a laminated film having higher formability and higher reusability than conventional ones.

In order to solve the above problems, the present invention employs the following configuration.
[1]. A laminated film, wherein the laminated film comprises a first resin layer and a second resin layer, the first resin layer and the second resin layer contain the same kind of polyolefin-based resin, and the laminated film is A laminated film having an elastic modulus E _F ′(110) of 1.5×10 ⁷ Pa or less at 110° C. when the vibration frequency is 1 Hz, when subjected to a physical viscoelasticity measurement.
[2]. As a test piece for the second resin layer, a second test piece having the same composition as the second resin layer and the same thickness as the laminated film is prepared, and the second test piece is subjected to dynamic The laminated film according to [1], wherein the elastic modulus E ₂ ′(110) at 110° C. when the vibration frequency is 1 Hz is 5.0×10 ⁵ Pa or more when viscoelasticity measurement is performed.
[3]. The laminated film further comprises a third resin layer between the first resin layer and the second resin layer, wherein the first resin layer, the second resin layer, and the third resin layer are , the laminated film according to [1] or [2], which contains the same kind of polyolefin resin.

[4]. As a test piece for the first resin layer, a first test piece having the same composition as the first resin layer and the same thickness as the laminated film is prepared, and as a test piece for the second resin layer , A second test piece having the same composition as the second resin layer and the same thickness as the laminated film is prepared, and dynamic viscoelasticity measurement is performed on the first test piece, Elastic modulus E ₁ '(85) at 85 ° C. when the vibration frequency is 1 Hz and 85 ° C. when the vibration frequency is 1 Hz when dynamic viscoelasticity measurement is performed on the second test piece and the elastic modulus E ₂ '(85) at the following formula:
E ₁ '(85)/E ₂ '(85) ≤ 0.80
The laminated film according to any one of [1] to [3], which satisfies
[5]. The laminated film according to any one of [1] to [4], wherein the second resin layer contains two or more of the same polyolefin resin.
[6]. The laminated film according to any one of [1] to [5], wherein the ratio of the thickness of the second resin layer to the thickness of the entire laminated film is 40% or less.

[7]. The laminated film according to any one of [1] to [6], wherein the laminated film is for a deep drawing package.
[8]. A package constructed using the laminated film according to any one of [1] to [7].

ADVANTAGE OF THE INVENTION According to this invention, the laminated|multilayer film with higher moldability than before and high reusability is provided.

BRIEF DESCRIPTION OF THE DRAWINGS It is sectional drawing which shows typically an example of the laminated|multilayer film which concerns on one Embodiment of this invention. BRIEF DESCRIPTION OF THE DRAWINGS It is sectional drawing which shows typically an example of the package comprised using the laminated|multilayer film which concerns on one Embodiment of this invention.

<<Laminated film>>
In one embodiment of the present invention, a laminated film comprises a first resin layer and a second resin layer, the first resin layer and the second resin layer contain the same type of polyolefin resin, and the laminated film is According to a physical viscoelasticity measurement, the elastic modulus E _F ′(110) at 110° C. when the vibration frequency is 1 Hz is 1.5×10 ⁷ Pa or less.
As used herein, "elastic modulus" means "storage elastic modulus" unless otherwise specified.

Since the first resin layer and the second resin layer of the laminated film of the present embodiment contain the same kind of polyolefin resin, the laminated film is highly reusable.
In addition, since the laminated film of the present embodiment has an E _F ′(110) of 1.5×10 ⁷ Pa or less, it can be easily molded into a desired shape and has high moldability. The laminated film having such high moldability is suitable for, for example, a deep-drawn package.

<First resin layer>
The first resin layer includes a polyolefin resin.
The polyolefin resin contained in the first resin layer is not particularly limited as long as it has a structural unit derived from an olefin. It may be an olefin copolymer.

Examples of the olefin homopolymer include low density polyethylene (LDPE), linear low density polyethylene (LLDPE), metallocene catalyst linear low density polyethylene (mLLDPE), medium density polyethylene (MDPE), and high density polyethylene. polyethylene such as (HDPE); polypropylene (homopolypropylene);
Linear low density polyethylene (LLDPE) and metallocene-catalyzed linear low density polyethylene (mLLDPE) are both types of low density polyethylene (LDPE).

Classification of polyethylene according to its density was defined, for example, in the old JIS K 6748:1995. For purposes of this specification, this definition classifies polyethylene according to its density.
That is, in this specification, low-density polyethylene (LDPE) means polyethylene having a density of 0.91 g/cm ³ or more and less than 0.93 g/cm ³ .
Medium density polyethylene (MDPE) means polyethylene having a density of 0.93 g/cm ³ or more and less than 0.942 g/cm ³ .
High density polyethylene (HDPE) means polyethylene having a density of 0.942 g/cm ³ or more.

Examples of the olefin copolymer include an ethylene copolymer having at least a structural unit derived from ethylene and a propylene copolymer having at least a structural unit derived from propylene.

The ethylene-based copolymer has a structural unit derived from ethylene and a structural unit derived from a monomer other than ethylene. However, in an olefin copolymer having a structural unit derived from ethylene and a structural unit derived from propylene, the number of structural units derived from propylene is equal to the number of structural units derived from ethylene. Copolymers greater than 1000 are conveniently classified as propylene-based copolymers.

Ethylene-based copolymers include, for example, ethylene-vinyl acetate copolymer (EVA), ethylene-vinyl alcohol copolymer (EVOH, also known as saponified ethylene-vinyl acetate copolymer), ethylene-vinyl alcohol-acetic acid. Vinyl copolymer (also known as ethylene-vinyl acetate copolymer partially saponified product, sometimes referred to as "EVA partially saponified product" in this specification), ethylene-methyl acrylate copolymer (EMA), ethylene- Methyl methacrylate copolymer (EMMA), ethylene-ethyl acrylate copolymer (EEA), ethylene-acrylic acid copolymer (EAA), ethylene-methacrylic acid copolymer (EMAA), ethylene-ethyl acrylate- Maleic anhydride copolymers (E-EA-MAH), ionomers (ION) and the like can be mentioned.
As the ionomer, for example, a copolymer of ethylene and a small amount of acrylic acid or methacrylic acid is a resin having an ion-bridged structure through salt formation between an acid moiety therein and a metal ion. mentioned.

The propylene-based copolymer has a structural unit derived from propylene and a structural unit derived from a monomer other than propylene.
Examples of propylene-based copolymers include propylene-ethylene random copolymers (also known as polypropylene random copolymers (rPP)) and propylene-ethylene block copolymers (also known as polypropylene block copolymers (bPP)).

The polyolefin-based resin contained in the first resin layer may be of only one type, or may be of two or more types. can be selected to

In the present specification, polyethylene (ethylene homopolymer) and the ethylene-based copolymer are collectively referred to as "polyethylene-based resin". Similarly, polypropylene (homopolypropylene, homopolymer of propylene) and the propylene-based copolymer are collectively referred to as "polypropylene-based resin".

The polyolefin-based resin contained in the first resin layer is preferably a polyethylene-based resin, and is composed of low-density polyethylene, linear low-density polyethylene, metallocene-catalyzed linear low-density polyethylene, and ethylene-vinyl acetate copolymer. More preferably, one or more selected from the group.

The first resin layer may contain other components in addition to the polyolefin-based resin as long as the effects of the present invention are not impaired.
The other components include resin components (herein sometimes referred to as "other resin components") and non-resin components (herein sometimes referred to as "other non-resin components"). ).

The other resin component is not particularly limited as long as it is a resin other than the polyolefin resin.

Examples of the other non-resin components include additives known in the art.
Examples of the additives include antifog agents, antiblocking agents, antioxidants, antistatic agents, crystal nucleating agents, inorganic particles, viscosity reducers, thickeners, heat stabilizers, lubricants, infrared absorbers, An ultraviolet absorber etc. are mentioned.

The other components contained in the first resin layer may be only one type, or may be two or more types, and when there are two or more types, the combination and ratio thereof may be arbitrary depending on the purpose. can be selected to

In the first resin layer, the content of the polyolefin resin with respect to the total mass of the first resin layer (polyolefin resin of the same kind as the polyolefin resin contained in the second resin layer, and polyolefin resin contained in the second resin layer The total content of polyolefin resins that are not the same type) is preferably 90 to 100% by mass, more preferably 95 to 100% by mass, for example, 97 to 100% by mass, and 99% by mass. It may be anywhere from 100% by mass to 100% by mass. When the ratio is equal to or higher than the lower limit, the effects of the polyolefin-based resin contained in the first resin layer can be obtained more remarkably.
The ratio is usually the content of the polyolefin resin (polyolefin of the same kind as the polyolefin resin contained in the second resin layer) with respect to the total content (parts by mass) of the components that do not vaporize at room temperature in the first resin composition described later. is the same as the total content of the polyolefin-based resin and the polyolefin-based resin that is not the same as the polyolefin-based resin contained in the second resin layer) (parts by mass).

As used herein, the term "ordinary temperature" means a temperature that is not particularly cooled or heated, that is, a normal temperature.

The first resin layer and the second resin layer contain the same kind of polyolefin resin.
In the present embodiment, not only in the case of polyolefin-based resins, but when resins having a common structural unit are compared with each other, the term "resin of the same type" refers to , means that the ratio of the amount (mole) of common structural units is 20 mol % or more. For example, low density polyethylene (LDPE), linear low density polyethylene (LLDPE), metallocene-catalyzed linear low density polyethylene (mLLDPE), medium density polyethylene (MDPE), high density polyethylene (HDPE), ethylene-methyl acrylate. Copolymer (EMA resin), ethylene-methyl methacrylate copolymer (EMMA resin), ethylene-vinyl alcohol copolymer (EVOH), ethylene-vinyl acetate copolymer (EVA), ethylene-vinyl alcohol-vinyl acetate All of the copolymers (partially saponified EVA) and the like are of the same type because the ratio of the amount (mol) of the structural unit derived from ethylene to the total amount (mol) of the structural units is 20 mol% or more. and On the other hand, for example, in propylene-ethylene random copolymers, propylene-ethylene block copolymers, etc., the ratio of the amount (mol) of structural units derived from ethylene to the total amount (mol) of structural units is 20 mol. % is not the same as the above-mentioned low-density polyethylene or the like.
In the present embodiment, the same type of resin preferably has a ratio of the amount (mol) of common structural units to the total amount (mol) of the structural units in both resins, preferably 30 mol% or more, more preferably 40 mol. % or more, more preferably 50 mol % or more, and may be, for example, 60 mol % or more, 70 mol % or more, or 80 mol % or more.

In the first resin layer, the content ratio of the polyolefin resin of the same kind as the polyolefin resin contained in the second resin layer with respect to the total mass of the first resin layer is preferably 80 to 100% by mass, and preferably 90 to 90% by mass. It is more preferably 100% by mass, and may be, for example, 95 to 100% by mass or 99 to 100% by mass. When the ratio is equal to or higher than the lower limit, the reusability of the laminated film becomes higher.

When the first resin layer contains one or more selected from the group consisting of low-density polyethylene, linear low-density polyethylene, metallocene-catalyzed linear low-density polyethylene, and ethylene-vinyl acetate copolymer, In one resin layer, the ratio of the total content of low density polyethylene, linear low density polyethylene, metallocene catalyst linear low density polyethylene and ethylene-vinyl acetate copolymer to the total mass of the first resin layer is 70. It is preferably up to 100% by mass, more preferably 80 to 100% by mass, even more preferably 90 to 100% by mass. The proportion is equal to or higher than the lower limit, and the first resin layer contains low-density polyethylene, linear low-density polyethylene, metallocene-catalyzed linear low-density polyethylene, or ethylene-vinyl acetate copolymer. The effect obtained is higher.

As a test piece for the first resin layer, a first test piece having the same composition as the first resin layer and the same thickness as the laminated film was prepared. When the measurement (DMA: Dynamic Mechanical. Analysis) is performed, the elastic modulus E ₁ '(85) at 85°C when the vibration frequency is 1 Hz is E ₁ '(85)/E ₂ '(85 ) value is a target value, preferably 5.0×10 ⁴ to 1.0×10 ⁹ Pa, and 8.0×10 ⁴ to 5.0×10 ⁸ Pa. is more preferably 1.0×10 ⁵ to 6.0×10 ⁷ Pa. When E ₁ '(85) is within such a range, the moldability of the laminated film is further improved, and the seal strength when the first resin layer is a sealant layer is further improved.

The first test piece to be subjected to the dynamic viscoelasticity measurement has a width of 4 mm and a length of 5 cm or more. Using such a first test piece, the first test piece is placed so that the length of the measurement target site for dynamic viscoelasticity measurement is 2 cm, and the first test piece is heated at a temperature increase rate of 3. It is preferable to measure the dynamic viscoelasticity by raising the temperature at a rate of °C/min. Under such conditions, E ₁ ′ (85) can be measured with higher accuracy.

E ₁ ′ (85) can be adjusted by adjusting the type of component contained in the first resin layer, the amount of the component contained, the thickness, or the like.

The first resin layer may consist of one layer (single layer), or may consist of a plurality of layers of two or more layers. When the first resin layer consists of multiple layers, these multiple layers may be the same or different, and the combination of these multiple layers is not particularly limited as long as the effects of the present invention are not impaired.

In this specification, not only in the case of the first resin layer, "multiple layers may be the same or different" means "all the layers may be the same or all the layers may be different. "A plurality of layers may be the same, or only some of the layers may be the same." means that

The thickness of the first resin layer can be arbitrarily set according to the application of the laminated film, and is not particularly limited.
The thickness of the first resin layer is usually preferably 5 to 145 μm, more preferably 5 to 98 μm, even more preferably 5 to 95 μm, and may be, for example, 5 to 30 μm. . When the thickness of the first resin layer is equal to or greater than the lower limit, the strength of the first resin layer is further improved, and the effect of the laminated film including the first resin layer is more significantly obtained. . Since the thickness of the first resin layer is equal to or less than the upper limit, excessive thickness is suppressed.
When the first resin layer consists of multiple layers, the total thickness of these multiple layers is preferably within the above numerical range.

The ratio of the thickness of the first resin layer to the thickness of the entire laminated film is not particularly limited, and is, for example, 3 to 95%, 3 to 90%, 3 to 80%, 5 to 30%, and 5 to Any of 15% may be sufficient. When the ratio is within such a range, the same effect as when the thickness of the first resin layer is within the above range can be obtained.

The first resin layer is preferably a non-stretched layer (film). Since the first resin layer is a non-stretched layer, the moldability of the laminated film is improved.

The first resin layer is suitable, for example, as a sealant layer.

<Second resin layer>
The second resin layer contains the same polyolefin resin as the polyolefin resin contained in the first resin layer.
The polyolefin-based resin of the same type contained in the second resin layer may be of only one type, or may be of two or more types. It can be selected arbitrarily.

The second resin layer preferably contains a polyethylene-based resin as the polyolefin-based resin of the same type, and is selected from the group consisting of high-density polyethylene, low-density polyethylene, linear low-density polyethylene, and metallocene-catalyzed linear low-density polyethylene. It is more preferable to include one or more selected types. The second resin layer contains one or more selected from the group consisting of polyethylene-based resins, particularly high-density polyethylene, low-density polyethylene, linear low-density polyethylene, and metallocene-catalyzed linear low-density polyethylene. Thus, it becomes easy to adjust E ₂ ′ (110) to a target value, and furthermore, it becomes easy to adjust E _F ′ (110) to a target value.

When the second resin layer contains two or more of the same polyolefin-based resins, it becomes easier to adjust the E ₂ '(110) to the target value, and further, the E _F '(110) is the target value. It becomes easier to adjust the value to

When the second resin layer contains high-density polyethylene as the polyolefin-based resin of the same type, it is further selected from the group consisting of low-density polyethylene, linear low-density polyethylene, and metallocene-catalyzed linear low-density polyethylene. It may or may not contain a species or two or more species. When the second resin layer contains high-density polyethylene, the total content of low-density polyethylene, linear low-density polyethylene, and metallocene-catalyzed linear low-density polyethylene makes its E ₂ '(110) the target value , and it is easier to adjust E _F ′ (110) to a target value.

When the second resin layer contains high-density polyethylene and one or more selected from the group consisting of low-density polyethylene, linear low-density polyethylene, and metallocene-catalyzed linear low-density polyethylene, In the two resin layers, [content of high-density polyethylene (parts by mass)]: mass ratio of [total content of low-density polyethylene, linear low-density polyethylene and metallocene-catalyzed linear low-density polyethylene (parts by mass)] is preferably 80:20 to 20:80, and may be, for example, any of 80:20 to 60:40, 20:80 to 40:60, and 60:40 to 40:60.

The second resin layer may contain other components in addition to the polyolefin-based resin of the same kind as the polyolefin-based resin contained in the first resin layer, as long as the effects of the present invention are not impaired.
The other components in the second resin layer include resin components (herein sometimes referred to as "other resin components") and non-resin components (herein, "other non-resin components"). may be referred to as).

The other resin component in the second resin layer is not particularly limited as long as it is a resin other than the polyolefin resin of the same type as the polyolefin resin contained in the first resin layer.
Examples of the other resin component in the second resin layer include a polyolefin resin that is not the same as the polyolefin resin contained in the first resin layer, and a resin other than the polyolefin resin.
Examples of the polyolefin-based resin that is not the same as the polyolefin-based resin included in the first resin layer include the same polyolefin-based resins as the polyolefin-based resin included in the first resin layer.

Examples of the non-resin component in the second resin layer include those similar to the non-resin component in the first resin layer.

The other components contained in the second resin layer may be one type or 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 to

In the second resin layer, the content of the polyolefin resin with respect to the total mass of the second resin layer (polyolefin resin of the same kind as the polyolefin resin contained in the first resin layer and polyolefin resin of the same kind as the first resin layer The total content of polyolefin resin that is not) is preferably 90 to 100% by mass, more preferably 95 to 100% by mass, for example, 97 to 100% by mass, and 99 to Any of 100 mass % may be sufficient. When the ratio is equal to or higher than the lower limit, the effect of the second resin layer containing the polyolefin resin can be obtained more remarkably.
The ratio is usually the content of the polyolefin resin (polyolefin of the same kind as the polyolefin resin contained in the first resin layer) with respect to the total content (parts by mass) of the components that do not vaporize at room temperature in the second resin composition described later. is the same as the total content of the polyolefin-based resin and the polyolefin-based resin that is not the same as the polyolefin-based resin contained in the first resin layer) (parts by mass).

In the second resin layer, the content ratio of the polyolefin resin of the same kind as the polyolefin resin contained in the first resin layer with respect to the total mass of the second resin layer is preferably 80 to 100% by mass, and preferably 90 to 90% by mass. It is more preferably 100% by mass, and may be, for example, 95 to 100% by mass or 99 to 100% by mass. When the ratio is equal to or higher than the lower limit, the reusability of the laminated film becomes higher.

When the second resin layer contains high-density polyethylene, in the second resin layer, high-density polyethylene, low-density polyethylene, linear low-density polyethylene, and metallocene-catalyzed linear low-density polyethylene relative to the total mass of the second resin layer is preferably 80 to 100% by mass, more preferably 90 to 100% by mass, and may be, for example, 95 to 100% by mass. When the ratio is equal to or higher than the lower limit, the moldability of the laminated film is remarkably improved.

As a test piece for the second resin layer, a second test piece having the same composition as the second resin layer and the same thickness as the laminated film was prepared. When measured (DMA), the elastic modulus E ₂ ′ (110) at 110° C. when the vibration frequency is 1 Hz is preferably 5.0×10 ⁵ Pa or more, and 5.0×10 It is more preferably ⁶ Pa or higher, and even more preferably 1.0×10 ⁷ Pa or higher. When E ₂ ′(110) is at least the lower limit, the moldability of the laminated film is further improved.
The upper limit of E ₂ ′(110) is not particularly limited. For example, a second resin layer having E ₂ ′(110) of 5.0×10 ⁸ Pa or less can be formed more easily.
E ₂ ′ (110) is, for example, 5.0×10 ⁵ to 5.0×10 ⁸ Pa, 5.0×10 ⁶ to 5.0×10 ⁸ Pa, and 1.0×10 ⁷ to 5.0×10 8 Pa. It may be either 0×10 ⁸ Pa.

The second test piece for dynamic viscoelasticity measurement may have a width of 4 mm and a length of 5 cm or more. Using such a second test piece, the second test piece is placed so that the length of the measurement target site for dynamic viscoelasticity measurement is 2 cm, and the second test piece is heated at a temperature increase rate of 3. It is preferable to measure the dynamic viscoelasticity by raising the temperature at a rate of °C/min. Under such conditions, E ₂ ′(110) can be measured with higher accuracy.

When dynamic viscoelasticity measurement (DMA) was performed on the second test piece, the elastic modulus E ₂ '(85) at 85 ° C. when the vibration frequency was 1 Hz was E ₁ '(85)/ The E ₂ ′ (85) value is preferably a target value, preferably 5.0×10 ⁵ to 1.0×10 ⁹ Pa, and 5.0×10 ⁶ to 7.0× It is more preferably 10 ⁸ Pa, and even more preferably 1.0×10 ⁷ to 4.0×10 ⁸ Pa. When E ₂ ′ (85) is within such a range, the moldability of the laminated film is further improved.
E ₂ ' (85) can be measured in the same manner as E ₂ ' (110), except that the temperature of the second specimen during the measurement is different. The second specimen measuring E ₂ ′ (85) is the same as the second specimen measuring E ₂ ′ (110).

E ₂ ' (110) and E ₂ ' (85) can be adjusted by adjusting the type of component contained in the second resin layer, the amount of the component contained, the thickness, or the like.

The second resin layer may be irradiated with an electron beam. That is, the laminated film may be irradiated with an electron beam, and preferably is irradiated with an electron beam from the second resin layer side. For example, even if the second resin layer does not contain high-density polyethylene, the second resin layer can easily adjust its E ₂ '(110) to a target value by electron beam irradiation. Furthermore, it becomes easy to adjust E _F ' (110) to a target value. The reason for this is presumed to be that the electron beam irradiation increases the crosslink density of the resin in the second resin layer.

A preferable example of the second resin layer irradiated with an electron beam is a second resin layer not irradiated with an electron beam containing low-density polyethylene (in this specification, the second resin layer in this case is referred to as an electron beam In order to distinguish it from the one after irradiation, it may be referred to as an "unirradiated second resin layer"), which has been irradiated with an electron beam.
That is, the laminated film that is irradiated with electron beams is preferable, for example, the laminated film that contains low-density polyethylene as the non-irradiated second resin layer (in this specification, the laminated film in this case In order to distinguish the film from the film after electron beam irradiation, it may be referred to as an “unirradiated laminated film”), and the film irradiated with electron beams may be mentioned.

In the non-irradiated second resin layer, the content ratio of the low-density polyethylene to the total weight of the non-irradiated second resin layer is preferably 70 to 100% by mass, more 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, the effect of electron beam irradiation can be obtained more remarkably.

It is preferable to irradiate the non-irradiated second resin layer or the non-irradiated laminate film with an absorbed dose of 20 to 300 kGy. When the absorbed dose is equal to or higher than the lower limit, the effect of electron beam irradiation can be obtained more remarkably. Excessive cross-linking of the resin in the second resin layer is suppressed when the absorbed dose is equal to or less than the upper limit.
In other words, a preferred laminated film irradiated with an electron beam is one irradiated with an electron beam under the condition of an absorbed dose of 20 to 300 kGy.

The acceleration voltage of the non-irradiated second resin layer or the non-irradiated laminated film when electron beam irradiation is preferably 100 to 300 kV, more preferably 120 to 280 kV, and even more preferably 140 to 260 kV. When the acceleration voltage is equal to or higher than the lower limit, the effect of electron beam irradiation can be obtained more remarkably. Excessive cross-linking of the resin in the second resin layer is suppressed when the acceleration voltage is equal to or less than the upper limit.

The laminate film has, for example, an increased gel fraction due to electron beam irradiation. That is, the gel fraction of the laminate film is greater than the gel fraction of the non-irradiated laminate film.
The gel fraction of the laminate film is preferably 30% or more, and may be, for example, 30 to 90%, 32 to 78%, or 34 to 76%. With such a laminated film, a desired elastic modulus can be easily obtained.

The gel fraction of the laminated film can be measured according to JIS K 6769. That is, the laminated film is immersed in an organic solvent such as xylene, and after drying the remaining insoluble matter without dissolution, the mass is determined, and the weight of the laminated film before dissolution and the insoluble matter derived from the laminated film after drying are calculated. The gel fraction can be calculated from the mass of the product. More specifically, for example, the laminated film of Xg is wrapped in a stainless steel wire mesh of Yg, immersed in a heated organic solvent, and the insoluble matter derived from the laminated film is taken out from the organic solvent together with the stainless steel wire mesh. . Next, the stainless wire mesh enveloping the insoluble matter is dried in a vacuum, and the total mass (Zg) of the dried insoluble matter and the stainless steel wire mesh is measured. The gel fraction of the laminated film is calculated from the following formula (1).
Gel fraction (mass%) of laminated film = (ZY) / X × 100 (1)

The laminate film changes its properties during thermomechanical analysis, for example, by electron beam irradiation.
For example, when a laminated film is subjected to thermomechanical analysis, the temperature at which a displacement of 2000 μm is exhibited (in this specification, it may be abbreviated as “2000 μm displacement temperature”) is preferably 120° C. or higher. , 125 to 200°C, and 130 to 195°C. With such a laminated film, a desired elastic modulus can be easily obtained.

For example, when the laminated film is subjected to thermomechanical analysis, the displacement at a temperature of 100° C. is preferably 500 μm or less, and may be, for example, 50 to 490 μm or 100 to 480 μm or less. With such a laminated film, a desired elastic modulus can be easily obtained.

Thermomechanical analysis of the laminated film is performed, for example, in accordance with JIS K 7196, from the difference in the amount of thermal expansion when the temperature of the standard sample and the target sample is increased at a constant rate, the amount of thermal expansion of the sample is determined. It can be done depending on the method of measurement.

The second resin layer may consist of one layer (single layer), or may consist of a plurality of layers of two or more layers. When the second resin layer consists of multiple layers, these multiple layers may be the same or different, and the combination of these multiple layers is not particularly limited as long as the effects of the present invention are not impaired.

The thickness of the second resin layer can be arbitrarily set according to the application of the laminated film, and is not particularly limited.
The thickness of the second resin layer is usually preferably 3 to 65 μm, more preferably 3 to 55 μm, even more preferably 3 to 40 μm, and may be, for example, 3 to 30 μm. . When the thickness of the second resin layer is equal to or greater than the lower limit, the strength of the second resin layer is further improved, and the effect of having the second resin layer in the laminated film is more significantly obtained. . Since the thickness of the second resin layer is equal to or less than the upper limit, excessive thickness is suppressed.
When the second resin layer consists of multiple layers, the total thickness of these multiple layers is preferably within the above numerical range.

The ratio of the thickness of the second resin layer to the thickness of the entire laminated film is preferably 40% or less, more preferably 30% or less, for example, 20% or less and 15% or less. It can be either. When the ratio is equal to or less than the upper limit, the moldability of the laminated film is further improved.
The ratio is preferably 3% or more in that the strength of the second resin layer is further improved and the effect of the laminated film provided with the second resin layer is more remarkably obtained.
Said percentage may be, for example, any of 3-40%, 3-30%, and 3-15%.

The second resin layer is preferably a non-stretched layer (film). Since the second resin layer is a non-stretched layer, the moldability of the laminated film is improved.

Since the second resin layer has heat resistance, it is suitable, for example, as an outer layer (the outermost layer on the side opposite to the sealant layer side).

In the laminated film, E ₁ ′ (85) and E ₂ ′ (85) are represented by the following formula:
E ₁ '(85)/E ₂ '(85) ≤ 0.80
is preferably satisfied. When the E ₁ '(85)/E ₂ '(85) value is equal to or less than the upper limit, the moldability of the laminated film is further improved.
From the viewpoint of enhancing such effects, the E ₁ ′(85)/E ₂ ′(85) value is more preferably 0.77 or less, and even more preferably 0.75 or less.
The lower limit of the E ₁ '(85)/E ₂ '(85) value is not particularly limited. For example, a laminate film having an E ₁ '(85)/E ₂ '(85) value of 0.0005 or more can be produced more easily.
E ₁ '(85)/E ₂ '(85) values may be, for example, any of 0.0005-0.80, 0.0005-0.77, and 0.0005-0.75 .

As the preferable laminated film, for example, the first resin layer and the second resin layer both contain a polyethylene resin as the polyolefin resin of the same type, and the first resin layer contains low density polyethylene as the polyethylene resin, One or more selected from the group consisting of linear low-density polyethylene, metallocene-catalyzed linear low-density polyethylene, and ethylene-vinyl acetate copolymer, and the second resin layer contains, as the polyethylene-based resin, , high-density polyethylene, and the second resin layer is further selected from the group consisting of low-density polyethylene, linear low-density polyethylene, and metallocene-catalyzed linear low-density polyethylene as the polyethylene-based resin, or Laminated films, which may or may not contain two or more kinds, may be mentioned.

In the laminated film, the ratio (thickness ratio) of [thickness of the first resin layer]/[thickness of the second resin layer] is not particularly limited. For example, it may be 0.15 to 10.0, preferably 0.15 to 3.0. When the thickness ratio is within such a range, the effect obtained by providing the first resin layer and the effect obtained by providing the second resin layer in the laminated film are more balanced. well obtained.

<Third resin layer>
The laminated film may further include a third resin layer between the first resin layer and the second resin layer.
The third resin layer contains the same polyolefin resin as the polyolefin resin contained in the first resin layer and the second resin layer. That is, in the laminated film having the third resin layer, the first resin layer, the second resin layer, and the third resin layer contain the same kind of polyolefin resin.

In the present embodiment, not only in the case of polyolefin-based resins, but when resins having a common structural unit are compared with each other, the term "resin of the same type" refers to , means that the ratio of the amount (mole) of common structural units is 20 mol % or more. For example, low density polyethylene (LDPE), linear low density polyethylene (LLDPE), metallocene-catalyzed linear low density polyethylene (mLLDPE), medium density polyethylene (MDPE), high density polyethylene (HDPE), ethylene-methyl acrylate. Copolymer (EMA resin), ethylene-methyl methacrylate copolymer (EMMA resin), ethylene-vinyl alcohol copolymer (EVOH), ethylene-vinyl acetate copolymer (EVA), ethylene-vinyl alcohol-vinyl acetate All of the copolymers (partially saponified EVA) and the like are of the same type because the ratio of the amount (mol) of the structural unit derived from ethylene to the total amount (mol) of the structural units is 20 mol% or more. and On the other hand, for example, in propylene-ethylene random copolymers, propylene-ethylene block copolymers, etc., the ratio of the amount (mol) of structural units derived from ethylene to the total amount (mol) of structural units is 20 mol. % is not the same as the above-mentioned low-density polyethylene or the like.
In the present embodiment, the same type of resin preferably has a ratio of the amount (mol) of common structural units to the total amount (mol) of the structural units in both resins, preferably 30 mol% or more, more preferably 40 mol. % or more, more preferably 50 mol % or more, and may be, for example, 60 mol % or more, 70 mol % or more, or 80 mol % or more.
The laminated film provided with the third resin layer has an effect due to the provision of the third resin layer, and is highly reusable.

The polyolefin-based resin of the same type contained in the third resin layer may be of only one type, or may be of two or more types. It can be selected arbitrarily.

The polyolefin-based resin of the same type contained in the third resin layer is preferably a polyethylene-based resin.
That is, it is preferable that all of the first resin layer, the second resin layer, and the third resin layer contain a polyethylene-based resin.

The polyolefin-based resin of the same type contained in the third resin layer is preferably linear low-density polyethylene or metallocene-catalyzed linear low-density polyethylene or both. Since the third resin layer contains either one or both of the linear low-density polyethylene and the metallocene-catalyzed linear low-density polyethylene, the laminated film has good pinhole resistance.

The third resin layer may contain other components in addition to the polyolefin resin of the same type as the polyolefin resin contained in the first resin layer and the second resin layer within a range that does not impair the effects of the present invention.
The other components in the third resin layer include resin components (herein sometimes referred to as "other resin components") and non-resin components (herein, "other non-resin components"). may be referred to as).

The other resin component in the third resin layer is not particularly limited as long as it is a resin other than the polyolefin resin of the same type as the polyolefin resin contained in the first resin layer and the second resin layer.
Examples of the other resin component in the third resin layer include a polyolefin resin that is not the same as the polyolefin resin contained in the first resin layer and the second resin layer, and a resin other than the polyolefin resin.

Polyolefin resins used in the third resin layer (included in the third resin layer) include elastomer components such as α-olefin copolymers; ethylene-vinyl alcohol copolymers (EVOH); ethylene-vinyl alcohol-vinyl acetate copolymers. (EVA partial saponification product) is also included. A laminated film having a third resin layer containing an elastomer has high pinhole resistance and high strength even if it does not contain a polyamide such as nylon. A laminated film having a third resin layer containing EVOH has oxygen barrier properties.

The polyolefin resin that is not the same as the polyolefin resin contained in the first resin layer and the second resin layer includes the same polyolefin resins as those mentioned above as the polyolefin resin contained in the first resin layer; elastomers such as α-olefin copolymers etc.
The laminated film having the third resin layer containing the elastomer has high pinhole resistance and high strength even if it does not contain a polyamide such as nylon.

Examples of resins other than polyolefin resins in the third resin layer include elastomers such as styrene-ethylene/butylene-ethylene block copolymers.
The laminated film having the third resin layer containing the elastomer has high pinhole resistance and high strength even if it does not contain a polyamide such as nylon.

Examples of the non-resin component in the third resin layer include those similar to the non-resin component in the first resin layer.

The other components contained in the third resin layer may be one type or 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 to

In the third resin layer, the content of the polyolefin resin with respect to the total mass of the third resin layer (polyolefin resin of the same kind as the polyolefin resin contained in the first resin layer and the second resin layer, the first resin layer and the The total content of the polyolefin resin contained in the two resin layers and the polyolefin resin that is not the same type) is preferably 90 to 100% by mass, more preferably 95 to 100% by mass. , 97 to 100 mass %, and 99 to 100 mass %. When the ratio is equal to or higher than the lower limit, the effect of the third resin layer containing the polyolefin resin can be obtained more remarkably.
The ratio is usually the content of the polyolefin-based resin (the polyolefin-based It is the same as the ratio of the total content of the polyolefin resin that is the same as the resin and the polyolefin resin that is not the same as the polyolefin resin contained in the first resin layer and the second resin layer (parts by mass).

In the third resin layer, the content ratio of the polyolefin-based resin of the same kind as the polyolefin-based resin contained in the first resin layer and the second resin layer with respect to the total mass of the third resin layer is 80 to 100% by mass. is preferred, and more preferably 90 to 100% by mass, for example, it may be either 95 to 100% by mass or 99 to 100% by mass. When the ratio is equal to or higher than the lower limit, the reusability of the laminated film becomes higher.

The third resin layer may consist of one layer (single layer), or may consist of a plurality of layers of two or more layers. When the third resin layer consists of multiple layers, these multiple layers may be the same or different, and the combination of these multiple layers is not particularly limited as long as the effects of the present invention are not impaired.
In the third resin layer consisting of multiple layers, all layers contain the same polyolefin resin as the polyolefin resin contained in the first resin layer and the second resin layer.

The thickness of the third resin layer can be arbitrarily set according to the application of the laminated film, and is not particularly limited.
The thickness of the third resin layer is generally preferably 15 to 200 μm, more preferably 30 to 160 μm, even more preferably 50 to 120 μm. When the thickness of the third resin layer is equal to or more than the lower limit, the strength of the third resin layer is further improved, and the effect of the laminated film including the third resin layer is more significantly obtained. . Since the thickness of the third resin layer is equal to or less than the upper limit, excessive thickness is suppressed.
When the third resin layer consists of multiple layers, the total thickness of these multiple layers is preferably within the above numerical range.

When the laminated film has a third resin layer, the ratio of the thickness of the third resin layer to the thickness of the entire laminated film is not particularly limited, but is preferably 3 to 90%. It may be either 55-90% or 70-90%. When the ratio is equal to or higher than the lower limit, the effect obtained by providing the third resin layer to the laminated film becomes higher. When the ratio is equal to or less than the upper limit, the effect obtained by providing the laminated film with the first resin layer and the second resin layer is enhanced.

When the laminated film has a third resin layer, the ratio of the total thickness of the first resin layer and the second resin layer to the thickness of the entire laminated film is not particularly limited, but is 10 to 97%. preferably 10 to 45% and 10 to 30%. When the ratio is equal to or higher than the lower limit, the effect obtained by providing the laminated film with the first resin layer and the second resin layer is enhanced. When the ratio is equal to or less than the upper limit, the effect obtained by providing the third resin layer in the laminated film becomes higher.

The third resin layer is preferably an unstretched layer (film). Since the third resin layer is a non-stretched layer, the moldability of the laminated film is improved.

The third resin layer is suitable, for example, as an intermediate layer such as a pinhole resistant layer and an oxygen barrier layer.

The laminated film has high pinhole resistance and high strength even if it does not contain a polyamide such as nylon.
For example, when the tip of a needle having a radius of curvature of 0.5 mm is pushed vertically into the laminated film at a speed of 500 mm/min, the moment the needle penetrates the laminated film, When the load applied to the needle is defined as piercing strength (N), it can be said that the higher the piercing strength, the higher the pinhole resistance of the laminated film.
Examples of the needle include those made of stainless steel.

The puncture strength of the laminated film is preferably 3N or higher, and may be, for example, 3.5N or higher or 4N or higher.
Although the upper limit of the puncture strength is not particularly limited, for example, a laminated film having a puncture strength of 12 N or less can be more easily realized.

A laminated film having a high puncture strength as described above, for example, is provided with a third resin layer, and can be more easily realized. By adjusting the type and content of the resin contained in the first resin layer, the second resin layer, and in some cases the third resin layer, the puncture strength of the laminated film can be adjusted.

A resin layer containing ethylene-vinyl alcohol copolymer (EVOH) has high oxygen barrier properties. Therefore, for example, the laminated film provided with the third resin layer containing ethylene-vinyl alcohol copolymer has oxygen barrier properties.

On the other hand, ethylene-vinyl alcohol copolymers are usually ethylene-vinyl acetate copolymers and ethylene-vinyl alcohol-vinyl acetate copolymers (in other words, ethylene-vinyl acetate copolymers and their partially saponified products). Low compatibility with polyolefin resins that do not fall under any of the above. Ethylene-vinyl alcohol-vinyl acetate copolymer (ethylene-vinyl acetate copolymer partial saponification product) usually has compatibility with ethylene-vinyl alcohol copolymer, and furthermore, ethylene-vinyl alcohol copolymer and ethylene-vinyl acetate copolymer and ethylene-vinyl alcohol-vinyl acetate copolymer (in this specification, referred to as "non-vinyl polyolefin resin" There is compatibility with Therefore, when the third resin layer contains the non-vinyl polyolefin resin and the ethylene-vinyl alcohol copolymer, the third resin layer further contains ethylene-vinyl alcohol- A resin layer containing a vinyl acetate copolymer (which may be referred to herein as "resin layer (I)") is preferred. The third resin layer, which is the resin layer (I), has high oxygen barrier properties.

In the resin layer (I), the non-vinyl polyolefin resin is the same polyolefin resin as the polyolefin resin contained in the first resin layer and the second resin layer, and is preferably a polyethylene resin.
In the resin layer (I), the ethylene-vinyl alcohol copolymer and the ethylene-vinyl alcohol-vinyl acetate copolymer are both polyolefin resins of the same type as the polyolefin resin contained in the first resin layer and the second resin layer. It is preferably a system resin.

Ethylene-vinyl alcohol in the resin layer (I) (the third resin layer containing the ethylene-vinyl alcohol copolymer, the non-vinyl polyolefin resin, and the ethylene-vinyl alcohol-vinyl acetate copolymer) In the copolymer, the ratio of the amount (mol) of the structural unit derived from ethylene to the total amount (mol) of the structural units is preferably 20 mol% or more, more preferably 20 to 80 mol%. Preferably, for example, 20 to 70 mol%, 20 to 60 mol%, and 20 to 50 mol%, or 30 to 80 mol%, 40 to 80 mol%, and 50 to 80 mol% or any one of 30 to 70 mol % and 40 to 60 mol %.

In the resin layer (I), the content of the ethylene-vinyl alcohol copolymer relative to the total weight of the resin layer (I) may be, for example, 25 to 70% by mass. However, in order to improve the uniformity and oxygen barrier properties of the resin layer (I), the ratio is preferably 40 to 70% by mass, more preferably 50 to 70% by mass. It may be 55 to 65% by mass.
The ratio is usually the total content (parts by mass) of the components that do not vaporize at room temperature in the resin composition for forming the resin layer (I) (the third resin composition described later), ethylene-vinyl alcohol It is the same as the ratio of the polymer content (parts by mass).

In the resin layer (I), the content ratio of the non-vinyl polyolefin resin to the total mass of the resin layer (I) may be, for example, 5 to 50% by mass. However, in order to improve the uniformity and oxygen barrier properties of the resin layer (I), the ratio is preferably 5 to 35% by mass, more preferably 5 to 20% by mass. It may be 5 to 15% by mass.
The ratio is usually the non-vinyl polyolefin with respect to the total content (parts by mass) of the components that do not vaporize at room temperature in the resin composition for forming the resin layer (I) (the third resin composition described later). It is the same as the ratio of the content (parts by mass) of the system resin.

In the resin layer (I), the ratio of the content of the ethylene-vinyl alcohol-vinyl acetate copolymer to the total weight of the resin layer (I) is preferably 20 to 40% by mass, for example 25 to 35%. % by mass. When the ratio is within such a range, the effect of using the ethylene-vinyl alcohol-vinyl acetate copolymer can be obtained more remarkably.
The ratio is usually ethylene-vinyl alcohol- It is the same as the ratio of the content (parts by mass) of the vinyl acetate copolymer.

In the resin layer (I), the total content of the ethylene-vinyl alcohol copolymer, the non-vinyl polyolefin resin, and the ethylene-vinyl alcohol-vinyl acetate copolymer with respect to the total mass of the resin layer (I) The amount ratio is preferably 90 to 100% by mass, more preferably 95 to 100% by mass, for example, 97 to 100% by mass and 99 to 100% by mass. . When the ratio is equal to or higher than the lower limit, the oxygen barrier property of the resin layer (I) becomes higher.
The ratio is usually the total content (parts by mass) of the components that do not vaporize at room temperature in the resin composition for forming the resin layer (I) (the third resin composition described later), ethylene-vinyl alcohol It is the same as the ratio of the total content (parts by mass) of the polymer, the non-vinyl polyolefin resin, and the ethylene-vinyl alcohol-vinyl acetate copolymer.

When the laminated film has the resin layer (I) as the third resin layer, it may have only one resin layer (I), or may have two or more layers. When the laminated film comprises two or more resin layers (I), these two or more resin layers (I) may be the same or different, and the combination of these resin layers (I) may be It is not particularly limited as long as it does not impair the effects of the invention.

As the laminated film having the resin layer (I) as the third resin layer, for example, one layer of the resin layer (I) and the first resin layer side and the second resin layer side of the resin layer (I) One or both of them may include one or two third resin layers other than the resin layer (I).
More specifically, as such a laminated film, for example, a first resin layer, one resin layer (I) (third resin layer), and one or two layers other than the resin layer (I) The third resin layer and the second resin layer are laminated in this order in the thickness direction, and the third resin layer is a total of two or three laminated films; the first resin layer , a third resin layer other than one or two resin layers (I), one resin layer (I) (third resin layer), and a second resin layer, in this order. A laminated film having a total of two or three third resin layers laminated in the longitudinal direction; a first resin layer and one or two third resin layers other than the resin layer (I) , one resin layer (I) (third resin layer), one or two third resin layers other than the resin layer (I), and the second resin layer in this order. A laminated film having a total of 3 to 5 layers of the third resin layer, which is laminated in the direction, may be mentioned.
In the laminated film exemplified here, the first resin layer, the resin layer (I), the third resin layer other than the resin layer (I), and the second resin layer all contain the same polyolefin resin.
In the laminated film exemplified here, each of the first resin layer and the second resin layer may be only one layer, or may be two or more layers.

As a preferred laminated film, for example, in terms of having oxygen barrier properties, the third resin layer is composed of a plurality of layers of 3 or more layers, at least one of which is composed of the non-vinyl polyolefin resin. , an ethylene-vinyl alcohol copolymer and an ethylene-vinyl alcohol-vinyl acetate copolymer (that is, the resin layer (I)).
The third resin layer, which is the resin layer (I), comprises the non-vinyl polyolefin resin, an ethylene-vinyl alcohol copolymer, and an ethylene-vinyl alcohol-vinyl acetate copolymer. One or more selected from the group may be the polyolefin resin of the same type as the polyolefin resin contained in the first resin layer and the second resin layer.
For example, when the non-vinyl polyolefin resin is the same kind of polyolefin resin, one or both of an ethylene-vinyl alcohol copolymer and an ethylene-vinyl alcohol-vinyl acetate copolymer , It may be the same kind of polyolefin resin, and both the ethylene-vinyl alcohol copolymer and the ethylene-vinyl alcohol-vinyl acetate copolymer may not be the same kind of polyolefin resin. .

In the laminated film having the resin layer (I) as the third resin layer, the ratio of the thickness of the resin layer (I) to the thickness of the entire laminated film is not particularly limited, but is 4 to 15%. is preferred. The resin layer (I) in which the proportion is equal to or higher than the lower limit has higher uniformity of thickness. When the ratio is equal to or less than the upper limit, the reusability of the laminated film becomes higher.

When the laminated film has the resin layer (I) as the third resin layer, under the conditions of a temperature of 23 ° C. and a relative humidity (RH) of 50%, measured in accordance with JIS K 7126-2:2006. The oxygen permeation amount of the laminated film may be 500 ml/(m ² · 24 h · atm) or less, but preferably 100 ml / (m ² · 24 h · atm) or less, and 50 ml / (m ² ·24 h·atm) or less, more preferably 25 ml/(m ² ·24 h·atm) or less, for example, it may be 10 ml/(m ² ·24 h·atm) or less. . On the other hand, the oxygen permeation amount of the laminated film is 0 ml/(m ² ·24 h·atm) or more.

The amount of oxygen permeation of the laminated film can be adjusted by adjusting the type of the component contained, the amount of the contained component, the thickness, etc., in any one of the layers constituting the laminated film.
For example, as described above, by configuring the laminated film with the third resin layer containing EVOH, the oxygen permeation amount of the laminated film can be easily reduced. However, this is only an example, and the adjustment of the oxygen permeation amount of the laminated film can also be performed by adjusting other layers.

When the laminated film has the resin layer (I) as the third resin layer, the haze of the laminated film measured from the outside on the second resin layer side is either 35% or less or 30% or less. However, it is preferably 20% or less. A laminated film having a haze of equal to or less than the upper limit has a higher oxygen barrier property. This is because the uniformity of the resin layer (I) is high and the oxygen barrier property of the resin layer (I) is high. Further, when the haze is equal to or less than the upper limit, the visibility of the contents in the package obtained using the laminated film is improved.
As used herein, "haze" means that measured according to JIS K 7136:2000.

As the preferable laminated film having a third resin layer, for example, the first resin layer, the second resin layer, and the third resin layer all contain a polyethylene resin as the polyolefin resin of the same type. , one or two selected from the group consisting of low-density polyethylene, linear low-density polyethylene, metallocene-catalyzed linear low-density polyethylene, and ethylene-vinyl acetate copolymer as the polyethylene-based resin in the first resin layer The second resin layer contains high-density polyethylene as the polyethylene-based resin, and the second resin layer further includes low-density polyethylene, linear low-density polyethylene, and a metallocene catalyst as the polyethylene-based resin. It may or may not contain one or more selected from the group consisting of linear low-density polyethylene, and the third resin layer may contain, as the polyethylene-based resin, a linear Laminate films comprising either or both low density polyethylene and metallocene-catalyzed linear low density polyethylene are included.

In the laminated film, each layer (the first resin layer, the second resin layer, and, in some cases, the third resin layer) that constitutes the film contains the same kind of polyolefin resin, so it is highly reusable. Instead, each layer can be adhered without an adhesive layer intervening. That is, the laminated film has high adhesion between layers even if it does not have an adhesive layer. In addition, such a laminated film having no adhesive layer can be manufactured at low cost.

In the laminated film, the ratio of the content of the same kind of polyolefin-based resin to the total mass of the laminated film is preferably 90% or more, more preferably 92% or more, and 95% or more. is more preferred. When the ratio is equal to or higher than the lower limit, the laminated film can be made into a monomaterial (the laminated film is made of a single material), and the entire laminated film can be easily reused.

When dynamic viscoelasticity measurement (DMA) was performed on the laminated film, the elastic modulus E _F '(110) at 110°C when the vibration frequency was 1 Hz was 1.5 × 10 ⁷ Pa or less. , 1.0×10 ⁷ Pa or less, and more preferably 9.5×10 ⁶ Pa or less. When E _F ′(110) is equal to or less than the upper limit, the laminate film has high moldability.
The lower limit of E _F '(110) is not particularly limited. For example, a laminated film having an E _F ′(110) of 5.0×10 ⁵ Pa or more can be produced more easily.
E _F ′(110) is, for example, 5.0×10 ⁵ to 1.5×10 ⁷ Pa, 5.0×10 ⁵ to 1.0×10 ⁷ Pa, and 5.0×10 ⁵ to 9.0×10 7 Pa. Either 5×10 ⁶ Pa may be used.

The laminate film for dynamic viscoelasticity measurement, that is, the laminate film test piece has a width of 4 mm and a length of 5 cm or more. Using such a laminated film test piece, the laminated film test piece was placed so that the length of the measurement target site for dynamic viscoelasticity measurement was 2 cm, and the laminated film test piece was heated at a temperature increase rate of 3. It is preferable to measure the dynamic viscoelasticity by raising the temperature at a rate of °C/min. Under such conditions, E _F ′(110) can be measured with higher accuracy.

E _F '(110) can be adjusted by adjusting the type of component, the amount of the component, the thickness, or the like in any of the layers constituting the laminated film. E _F ' (110) can be more easily adjusted by adjusting E ₁ ' (85), E ₂ ' (110), or E ₂ ' (85), especially as described above.

The total thickness of the laminated film is not particularly limited.
For example, laminate films having a total thickness of preferably 50 to 350 μm, more preferably 50 to 160 μm, even more preferably 80 to 150 μm have higher formability.

In the laminated film, all layers (for example, the first resin layer to the third resin layer) constituting the laminated film are preferably non-stretched layers (films). Such a non-stretched laminated film is particularly excellent in moldability, and is particularly suitable for forming, for example, a deep-drawn package.

FIG. 1 is a cross-sectional view schematically showing an example of the laminated film of this embodiment.
The laminated film 1 shown here includes a first resin layer 11 and a second resin layer provided on one surface (hereinafter sometimes referred to as "first surface") 11a of the first resin layer 11. a layer 12;
The laminated film 1 further includes a third resin layer 13 between the first resin layer 11 and the second resin layer 12 .
That is, the laminated film 1 is configured by laminating the first resin layer 11, the third resin layer 13 and the second resin layer 12 in this order in the thickness direction thereof.
The first resin layer 11, the second resin layer 12 and the third resin layer 13 are all described above.
The third resin layer 13 has an arbitrary configuration, and the laminated film 1 does not have to include the third resin layer 13 .

One surface 11b of the first resin layer 11 (the surface opposite to the second resin layer 12 side, sometimes referred to as the "second surface" in this specification) 11b is an exposed surface.
One surface 12a of the second resin layer 12 (the surface opposite to the first resin layer 11 side, sometimes referred to as "first surface" in this specification) 12a is an exposed surface.

E _F '(110) of the laminated film 1 is 1.5×10 ⁷ Pa or less.

The laminated film may include other layers that do not correspond to any of the first resin layer, the second resin layer, and the third resin layer within a range that does not impair the effects of the present invention. , preferably without said other layer.
The other layer is a layer that does not contain a polyolefin resin, and by not including such another layer, the reusability of the laminated film is further enhanced.

<<Method for producing laminated film>>
The laminated film can be produced, for example, by using several extruders to melt-extrude a resin or a resin composition, which is a material for forming each layer, by a feed block method, a co-extrusion T-die method such as a multi-manifold method, or an air-cooling method. Alternatively, it can be produced by a water-cooled co-extrusion inflation method or the like.

In addition, in the laminated film, two or more films for constituting two or more layers of them are prepared separately in advance and laminated by a thermal (heat) lamination method or the like without using an adhesive. It can also be produced by laminating layers together, and, if necessary, further laminating layers other than these layers so as to obtain the desired arrangement form.

The type and content of the components contained in the resin composition, which is a material for forming any layer in the laminated film, are adjusted so that the layer to be formed contains the target component at the target content. and manufacture it. For example, the content ratio of the components that do not vaporize at room temperature in the resin composition is usually the same as the content ratio of the components in the layer formed from the resin composition.

As a resin composition for forming the first resin layer (the first resin layer 11 in the laminated film 1 shown in FIG. 1) (in this specification, it may be referred to as the "first resin composition") , for example, those containing the polyolefin-based resin and, if necessary, other components. The other ingredients are the ingredients described above.

As a resin composition for forming the second resin layer (the second resin layer 12 in the laminated film 1 shown in FIG. 1) (in this specification, it may be referred to as a "second resin composition") , for example, those containing the polyolefin-based resin and, if necessary, other components. The other ingredients are the ingredients described above.

As a resin composition for forming the third resin layer (the third resin layer 13 in the laminated film 1 shown in FIG. 1) (in this specification, it may be referred to as the "third resin composition") , for example, those containing the polyolefin-based resin and, if necessary, other components. The other ingredients are the ingredients described above.

<< package >>
The laminated film is suitable as a material for packaging.
That is, as a preferred package, there is a package configured using the laminated film.
The package of this embodiment can be manufactured by packaging an object to be packaged using the laminated film. When manufacturing the package, the first resin layer in the laminated film may be arranged on the side of the object to be packaged, and the second resin layer may be arranged on the side opposite to the side of the object to be packaged to package the object. preferable.

For example, the laminated film is suitable for a deep-drawn package, and suitable for constituting both the lid material and the bottom material of the deep-drawn package. In particular, the laminated film, which has good formability, is suitable for forming a bottom member having a concave portion for forming a storage portion.

FIG. 2 is a cross-sectional view schematically showing an example of a package provided with the laminated film of this embodiment.
A package 101 shown here includes a lid member 8 and a bottom member 10, and is a deep-drawn package obtained by deep-drawing a resin film.
Either or both of the lid member 8 and the bottom member 10 are constructed using the laminated film 1 shown in FIG.
In the lid member 8 or the bottom member 10 in FIG. 2, distinction of each layer in the laminated film 1 constituting this is omitted.

A recess 100 is formed in the bottom member 10 .
One surface 10b of the area excluding the recess 100 of the bottom material 10 (herein sometimes referred to as the "second surface") and one surface of the lid material 8 (herein referred to as the "second surface") 8b, which may be referred to as "two surfaces", are both seal surfaces and are opposed to each other.
The package 101 is configured by sealing the lid member 8 and the bottom member 10 . More specifically, the second surface 10b of the bottom member 10 excluding the recessed portion 100 and the second surface 8b of the lid member 8 are overlapped and sealed in the vicinity of their peripheral edges. As a result, a storage portion 101a is formed between the second surface 10b of the bottom member 10 and the second surface 8b of the lid member 8 in the region of the recess 100 of the bottom member 10 . A stored item 9 is stored in the storage portion 101a.

When the bottom material 10 is constructed using the laminated film 1, one surface (second surface) 10b of the bottom material 10 is the same as the second surface 11b of the first resin layer 11 in the laminated film 1. is preferred. The other surface 10a of the bottom material 10 (which may be referred to herein as the "first surface") is preferably the same as the first surface 12a of the second resin layer 12 in the laminated film 1. .

When the lid member 8 is constructed using the laminated film 1, one surface (second surface) 8b of the lid member 8 is the same as the second surface 11b of the first resin layer 11 in the laminated film 1. is preferred. The other surface 8a of the lid member 8 (in this specification, sometimes referred to as the “first surface”) is preferably the same as the first surface 12a of the second resin layer 12 in the laminated film 1. .

In FIG. 2 , in the storage portion 101 a of the package 101 , there are some gaps between the contents 9 and the bottom material 10 and between the contents 9 and the lid material 8 . The existence of the gap is not essential in the package 101 in which the article 9 is stored.

Both the thickness of the flat portion of the bottom material 10 and the thickness of the lid material 8 may be the same as the thickness of the laminated film 1 described above.

Up to this point, a deep-drawn package has been described as an example of a package provided with the laminated film, but the package provided with the laminated film is not limited to the deep-drawn package, and other packages. may be

Up to this point, the package configured using the laminated film 1 shown in FIG. 1 has been described as an example of the package. It may be configured using the laminated film of the embodiment.

<<Method for manufacturing package>>
In the package, for example, the laminated films, or the laminated film and a resin film other than the laminated film form a storage portion for storing an object to be packaged (in other words, a stored object). The film can be manufactured by storing the objects to be packaged while the film is being packed, and heat-sealing the regions of the film other than the storage portion.

The present invention will be described in more detail below with reference to specific examples. However, the present invention is by no means limited to the examples shown below.

[Example 1]
<<Production of laminated film>>
A laminated film having the configuration shown in FIG. 1 was manufactured by the procedure described below.
That is, low-density polyethylene (LDPE) (“Sumikasen (registered trademark) L211” manufactured by Sumitomo Chemical Co., Ltd., density 0.924 g/cm ³ ) was prepared as a resin constituting the first resin layer.
High-density polyethylene (HDPE) (“Nipolon Hard (registered trademark) 4010” manufactured by Tosoh Corporation, density 0.964 g/cm ³ , melt mass flow rate 5.4 g/10 min) was prepared as a resin constituting the second resin layer.
Metallocene-catalyzed linear low-density polyethylene (mLLDPE) (“Umerit (registered trademark) 1520F” manufactured by Ube Maruzen Polyethylene Co., Ltd., density 0.913 g/cm ³ ) was prepared as a resin constituting the third resin layer.

By co-extrusion of the LDPE, the mLLDPE, and the HDPE in this order, the first resin layer (thickness 10 μm), the third resin layer (thickness 80 μm), the second resin layer (thickness A laminated film (thickness: 100 μm) was obtained by laminating these layers in this order in the thickness direction. The first resin layer, the third resin layer, and the second resin layer are all unstretched layers.

<<Evaluation of laminated film>>
<Measurement of E _F '(110)>
A laminated film test piece having a length of 15 cm and a width of 4 mm was cut from the laminated film obtained above, and this laminated film test piece was placed in a sample holder so that the length of the measurement target site was 2 cm.
Then, using a dynamic viscoelasticity measuring device ("DMA 7100" manufactured by Hitachi High-Tech Science), in a tensile mode, in a temperature range of 25 ° C. to 135 ° C., displacement 10 μm, vibration frequency 1 Hz, temperature increase rate 3 ° C./ The dynamic viscoelasticity measurement of the laminated film test piece was performed under the condition of min, and E _F ′(110) was measured. Table 1 shows the results.

<Measurement of E ₂ '(110) and E ₂ '(85)>
A test resin film (thickness 100 μm) was obtained by extrusion molding the HDPE.
A second test piece having a length of 15 cm and a width of 4 mm (thickness of 100 μm) is cut out from this test resin film, and the second test piece is placed in a sample holder so that the length of the measurement target site is 2 cm. did.
Then, using a dynamic viscoelasticity measuring device ("DMA 7100" manufactured by Hitachi High-Tech Science), in a tensile mode, in a temperature range of 25 ° C. to 135 ° C., displacement 10 μm, vibration frequency 1 Hz, temperature increase rate 3 ° C./ The second test piece was subjected to dynamic viscoelasticity measurement under the condition of min to measure E ₂ ′(110) and E ₂ ′(85). Table 1 shows the results.

<Measurement of E ₁ '(85)>
A test resin film (thickness 100 μm) was obtained by extrusion molding the LDPE.
A first test piece having a length of 15 cm and a width of 4 mm (thickness of 100 μm) is cut out from this test resin film, and the first test piece is placed in a sample holder so that the length of the measurement target site is 2 cm. did.
Then, the dynamic viscoelasticity measurement of the first test piece was performed in the same manner as the second test piece, and E ₁ ′(85) was measured. In addition, E ₁ '(85)/E ₂ '(85) values were calculated. Table 1 shows the results.

<Evaluation of moldability of laminated film>
Using a deep drawing machine ("R535" manufactured by MULTIVAC), under the following molding conditions, recesses (pockets) are formed in the laminated film obtained above and deep drawing is performed to produce six compacts. did.
[Molding condition]
Molding temperature: 110°C
Heating time: 1.5 seconds Molding time: 2.0 seconds Mold size used: Width 110 mm, length 150 mm, depth 30 mm, three of the four corners have a radius of curvature of 10 mm, and the remaining one has a radius of curvature of 10 mm. Curvature radius is 35mm.

For 3 of the 6 molded bodies obtained, the thickness at the four corners of these recesses was measured using a micrometer, and the moldability of the laminated film was evaluated according to the following criteria. Table 1 shows the results.
[Evaluation criteria]
A: The thinnest portion has a thickness of 18 μm or more, and is excellent in formability.
B: The thickness of the thinnest portion is 13 μm or more and less than 18 μm, and the moldability is poor.
C: The thickness of the thinnest part is less than 13 μm, and the moldability is poor.
D: The film was melt-deformed during molding, and the moldability was particularly poor.

<<Production and Evaluation of Laminated Film>>
[Example 2]
As the resin constituting the second resin layer, the mLLDPE (“Umerit (registered trademark) 1520F” manufactured by Ube Maruzen Polyethylene Co., Ltd., density 0.913 g/cm ³ ) was prepared.
A second resin composition (1) was prepared by mixing the HDPE (70 parts by mass) and the mLLDPE (30 parts by mass).
The first resin layer (thickness: 10 μm) and the third resin layer (thickness: 80 μm) and a second resin layer (10 μm in thickness) were laminated in this order in the thickness direction to obtain a laminated film (100 μm in thickness). The first resin layer, the third resin layer, and the second resin layer are all unstretched layers.
This laminated film was evaluated in the same manner as in Example 1. Table 1 shows the results.

[Example 3]
As the resin constituting the second resin layer, the mLLDPE (“Umerit (registered trademark) 1520F” manufactured by Ube Maruzen Polyethylene Co., Ltd., density 0.913 g/cm ³ ) was prepared.
A second resin composition (2) was prepared by mixing the HDPE (50 parts by mass) and the mLLDPE (50 parts by mass).
The first resin layer (thickness: 10 μm) and the third resin layer (thickness: 80 μm) and a second resin layer (10 μm in thickness) were laminated in this order in the thickness direction to obtain a laminated film (100 μm in thickness). The first resin layer, the third resin layer, and the second resin layer are all unstretched layers.
This laminated film was evaluated in the same manner as in Example 1. Table 1 shows the results.

[Example 4]
As the resin constituting the second resin layer, the mLLDPE (“Umerit (registered trademark) 1520F” manufactured by Ube Maruzen Polyethylene Co., Ltd., density 0.913 g/cm ³ ) was prepared.
A second resin composition (3) was prepared by mixing the HDPE (30 parts by mass) and the mLLDPE (70 parts by mass).
The first resin layer (thickness: 10 µm) and the third resin layer (thickness: 80 μm) and a second resin layer (10 μm in thickness) were laminated in this order in the thickness direction to obtain a laminated film (100 μm in thickness). The first resin layer, the third resin layer, and the second resin layer are all unstretched layers.
This laminated film was evaluated in the same manner as in Example 1. Table 1 shows the results.

[Example 5]
An ethylene-vinyl acetate copolymer (EVA) ("Evaflex (registered trademark) V5714C" manufactured by Mitsui-Dow Polychemicals, density 0.940 g/cm ³ ) was prepared as a resin constituting the first resin layer.
As the resin constituting the second resin layer, the mLLDPE (“Umerit (registered trademark) 1520F” manufactured by Ube Maruzen Polyethylene Co., Ltd., density 0.913 g/cm ³ ) was prepared.
A second resin composition (2) was prepared by mixing the HDPE (50 parts by mass) and the mLLDPE (50 parts by mass).
The first resin layer ( 10 μm thick), a third resin layer (80 μm thick), and a second resin layer (10 μm thick) laminated in this order in the thickness direction of these laminated films (100 μm thick ). The first resin layer, the third resin layer, and the second resin layer are all unstretched layers.
This laminated film was evaluated in the same manner as in Example 1. Table 1 shows the results.

[Comparative Example 1]
A first resin layer (thickness: 20 μm), a third resin layer (thickness: 70 μm), and a second resin layer were formed in the same manner as in Example 1, except that the conditions for co-extrusion of the resins were changed. (thickness 10 μm) were laminated in this order in the thickness direction to obtain a laminated film (thickness 100 μm). The first resin layer, the third resin layer, and the second resin layer are all unstretched layers.
This laminated film was evaluated in the same manner as in Example 1. Table 1 shows the results.

[Example 6]
As the resin constituting the second resin layer, the LDPE (“Sumikasen (registered trademark) L211” manufactured by Sumitomo Chemical Co., Ltd., density 0.924 g/cm ³ ) was prepared.
A second resin composition (4) was prepared by mixing the HDPE (70 parts by mass) and the LDPE (30 parts by mass).
The first resin layer (thickness: 10 μm) and the third resin layer (thickness: 80 μm) and a second resin layer (10 μm in thickness) were laminated in this order in the thickness direction to obtain a laminated film (100 μm in thickness). The first resin layer, the third resin layer, and the second resin layer are all unstretched layers.
This laminated film was evaluated in the same manner as in Example 1. Table 2 shows the results.

[Example 7]
As the resin constituting the second resin layer, the LDPE (“Sumikasen (registered trademark) L211” manufactured by Sumitomo Chemical Co., Ltd., density 0.924 g/cm ³ ) was prepared.
A second resin composition (5) was prepared by mixing the HDPE (50 parts by mass) and the LDPE (50 parts by mass).
The first resin layer (thickness: 10 µm) and the third resin layer (thickness: 80 μm) and a second resin layer (10 μm in thickness) were laminated in this order in the thickness direction to obtain a laminated film (100 μm in thickness). The first resin layer, the third resin layer, and the second resin layer are all unstretched layers.
This laminated film was evaluated in the same manner as in Example 1. Table 2 shows the results.

[Example 8]
As the resin constituting the second resin layer, the LDPE (“Sumikasen (registered trademark) L211” manufactured by Sumitomo Chemical Co., Ltd., density 0.924 g/cm ³ ) was prepared.
A second resin composition (6) was prepared by mixing the HDPE (30 parts by mass) and the LDPE (70 parts by mass).
The first resin layer (thickness: 10 µm) and the third resin layer (thickness: 80 μm) and a second resin layer (10 μm in thickness) were laminated in this order in the thickness direction to obtain a laminated film (100 μm in thickness). The first resin layer, the third resin layer, and the second resin layer are all unstretched layers.
This laminated film was evaluated in the same manner as in Example 1. Table 2 shows the results.

[Example 9]
As the resin constituting the first resin layer, the EVA (“Evaflex (registered trademark) V5714C” manufactured by Mitsui Dow Polychemicals, density 0.940 g/cm ³ ) was prepared.
As the resin constituting the second resin layer, the LDPE (“Sumikasen (registered trademark) L211” manufactured by Sumitomo Chemical Co., Ltd., density 0.924 g/cm ³ ) was prepared.
A second resin composition (5) was prepared by mixing the HDPE (50 parts by mass) and the LDPE (50 parts by mass).
The first resin layer ( 10 μm thick), a third resin layer (80 μm thick), and a second resin layer (10 μm thick) laminated in this order in the thickness direction of these laminated films (100 μm thick ). The first resin layer, the third resin layer, and the second resin layer are all unstretched layers.
This laminated film was evaluated in the same manner as in Example 1. Table 2 shows the results.

[Comparative Example 2]
As the resin constituting the second resin layer, the mLLDPE (“Umerit (registered trademark) 1520F” manufactured by Ube Maruzen Polyethylene Co., Ltd., density 0.913 g/cm ³ ) was prepared.
By co-extrusion of the LDPE and the mLLDPE in this order, the first resin layer (thickness 10 μm) and the second resin layer (thickness 90 μm) are laminated in the thickness direction. A structured laminate film (100 μm thick) was obtained. Both the first resin layer and the second resin layer are unstretched layers.
This laminated film was evaluated in the same manner as in Example 1. Table 2 shows the results.

[Example 10]
A first resin layer (thickness of 5 μm), a third resin layer (thickness of 85 μm), and a second resin layer were formed in the same manner as in Example 1 except that the conditions for co-extrusion of the resins were changed. (thickness 10 μm) were laminated in this order in the thickness direction to obtain a laminated film (thickness 100 μm). The first resin layer, the third resin layer, and the second resin layer are all unstretched layers.
This laminated film was evaluated in the same manner as in Example 1. Table 3 shows the results.

[Example 11]
As the resin constituting the first resin layer and the second resin layer, the mLLDPE (“Umerit (registered trademark) 1520F” manufactured by Ube Maruzen Polyethylene Co., Ltd., density 0.913 g/cm ³ ) was prepared.
A second resin composition (2) was prepared by mixing the HDPE (50 parts by mass) and the mLLDPE (50 parts by mass).
By co-extrusion of the mLLDPE and the second resin composition (2) in this order, the first resin layer (thickness 90 μm) and the second resin layer (thickness 10 μm) A laminated film (thickness: 100 μm) was obtained which was laminated in the thickness direction. Both the first resin layer and the second resin layer are unstretched layers.
This laminated film was evaluated in the same manner as in Example 1. Table 3 shows the results.

<<Production and Evaluation of Single Layer Film>>
[Comparative Example 3]
By extruding the HDPE, an unstretched monolayer film (thickness: 199 µm) composed of HDPE was obtained.
Then, this monolayer film was evaluated in the same manner as in Example 1. Table 3 shows the results.
In addition, in Table 3, this single layer film is shown as the second resin layer for convenience.

As is clear from the above results, in Examples 1 to 10, the laminated film was provided with the first resin layer, the second resin layer and the third resin layer, and the first resin layer, the second resin layer and the third resin layer However, it contained PE, and the main component was the same kind of polyolefin-based resin, and was highly recyclable. Furthermore, in Examples 1 to 11, the moldability of the laminated film was good.
In Example 11, the laminated film has a first resin layer and a second resin layer, the first resin layer and the second resin layer contain PE, and the main ingredients are polyolefin-based resins of the same kind. , was highly reusable. Furthermore, in Example 11, the moldability of the laminated film was good.

In Examples 1 to 11, E _F ′(110) was 9.04×10 ⁶ Pa or less (1.87×10 ⁶ to 9.04×10 ⁶ Pa).
In Examples 1 to 11, E ₂ ′(110) is 1.71×10 ⁷ Pa or more (1.71×10 ⁷ to 1.29×10 ⁸ Pa), and E ₂ ′(85) is It was 5.55×10 ⁷ to 2.90×10 ⁸ Pa.
In Examples 1-11, E ₁ '(85) was between 1.24×10 ⁵ and 4.12×10 ⁷ Pa.
In Examples 1 to 11, the E ₁ '(85)/E ₂ '(85) value was 0.74 Pa or less (0.001 to 0.74 Pa).
In Examples 1 to 11, the ratio of the thickness of the second resin layer to the total thickness of the laminated film was 10% or less (5 to 10%).

In contrast, in Comparative Example 1, the formability of the laminated film was poor. In Comparative Example 1, E _F ′(110) was 1.86×10 ⁷ Pa. In Comparative Example 1, the second resin layer of the laminated film was composed of HDPE, and the ratio of the thickness of the second resin layer to the thickness of the entire laminated film was 20%.

In Comparative Example 2, the laminated film was melted when evaluating the formability of the laminated film, and the formability could not be evaluated. Moreover, in Comparative Example 2, the laminated film and the second test piece melted, and E _F '(110) and E ₂ '(110) could not be measured. In Comparative Example 2, the second resin layer of the laminated film was composed of the LLDPE.

In Comparative Example 3, the formability of the single layer film was poor. In Comparative Example 3, E _F ′(110) measured in the same manner as for the laminated film was 1.29×10 ⁸ Pa. In Comparative Example 3, the monolayer film was composed of the HDPE.

INDUSTRIAL APPLICABILITY The present invention can be used to manufacture various types of packages that can be reused after use, and is particularly suitable for manufacturing deep-drawn packages.

DESCRIPTION OF SYMBOLS 1... Laminated film 11... 1st resin layer 12... 2nd resin layer 13... 3rd resin layer 101... Package (deep drawing package)
8 Lid material 9 Items to be stored 10 Bottom material

Claims (7)

A laminated film,
The laminated film comprises a first resin layer and a second resin layer,
The first resin layer is a sealant layer, the second resin layer is an outer layer,
The first resin layer and the second resin layer contain the same type of polyolefin resin,
In the first resin layer, the polyolefin resin is selected from the group consisting of low-density polyethylene, linear low-density polyethylene, metallocene-catalyzed linear low-density polyethylene, and ethylene-vinyl acetate copolymer, or including two or more
In the first resin layer, the total content of the low density polyethylene, linear low density polyethylene, metallocene catalyst linear low density polyethylene and ethylene-vinyl acetate copolymer with respect to the total mass of the first resin layer The proportion is 70 to 100% by mass,
The second resin layer contains high-density polyethylene as the polyolefin-based resin, and further one selected from the group consisting of low-density polyethylene, linear low-density polyethylene, and metallocene-catalyzed linear low-density polyethylene, or Two or more types may be included, and the second resin layer is one or two or more selected from the group consisting of the low-density polyethylene, linear low-density polyethylene, and metallocene-catalyzed linear low-density polyethylene. in the second resin layer, [the content of the high-density polyethylene (parts by mass)]: [the total of the low-density polyethylene, the linear low-density polyethylene and the metallocene-catalyzed linear low-density polyethylene content (parts by mass)] is 80:20 to 20:80,
The ratio of the thickness of the second resin layer to the thickness of the entire laminated film is 15% or less,
The laminated film has a total thickness of 50 to 160 μm,
The laminate film has an elastic modulus E _F ′(110) of 1.5×10 ⁷ Pa or less at 110° C. when the vibration frequency is 1 Hz, when dynamic viscoelasticity measurement is performed on the laminate film. As a test piece for the second resin layer, a second test piece having the same composition as the second resin layer and the same thickness as the laminated film is prepared, and the second test piece is subjected to dynamic _2. The laminated film according to claim 1, wherein the elastic modulus E2'(110) at 110[deg.] C. at a vibration frequency of 1 Hz is 5.0*10< ⁵ > Pa or more when viscoelasticity measurement is performed. The laminated film further comprises a third resin layer between the first resin layer and the second resin layer,
3. The laminated film according to claim 1, wherein said first resin layer, said second resin layer, and said third resin layer contain the same type of polyolefin resin. As a test piece for the first resin layer, prepare a first test piece having the same composition as the first resin layer and the same thickness as the laminated film,
As a test piece for the second resin layer, prepare a second test piece having the same composition as the second resin layer and the same thickness as the laminated film,
For the first test piece, the elastic modulus E ₁ '(85) at 85 ° C. when the vibration frequency is 1 Hz when the dynamic viscoelasticity measurement is performed, and the dynamic viscosity for the second test piece. The elastic modulus E ₂ ′ (85) at 85° C. when the vibration frequency is 1 Hz when the elastic measurement is performed is given by the following formula:
E ₁ '(85)/E ₂ '(85) ≤ 0.80
The laminated film according to any one of claims 1 to 3, which satisfies The laminated film according to any one of claims 1 to 4, wherein the second resin layer contains two or more of the same polyolefin resin. The laminated film according to any one of Claims 1 to 5, wherein the laminated film is for a deep drawing package. A package comprising the laminated film according to any one of claims 1 to 6 , wherein the first resin layer in the laminated film is arranged on the package object side .

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