JP2018069597A - Sealant film, laminate film using the same and packaging bag - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sealant film which is excellent in low adsorptivity, has a sufficient seal strength and is suppressed in the change of physical properties by γ-ray sterilization.SOLUTION: There is provided a sealant film 1 which comprises a polyolefin layer 11 containing a polyolefin and a polycycloolefin layer 12 containing a polycycloolefin as a main component which serves as the outermost layer, wherein the polycycloolefin comprises two or more structural units selected from a structural unit (A) derived from a dicyclopentadiene compound, a structural unit (B) derived from a tetracyclododecene compound and a structural unit (C) derived from a norbornene compound, the polycycloolefin has a glass transition temperature of 80°C or less, the polyolefin layer has a thickness of 10 to 40 μm and the polycycloolefin layer has a thickness of 5 to 20 μm. There is provided a sealant film in which the polycycloolefin is a ring-opened metathesis polymer of the compound and the carbon-carbon double bond is hydrogenated.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a sealant film, a laminated film using the same, and a packaging bag.

  Conventionally, as a packaging container for storing contents such as foods, beverages, and pharmaceuticals, for example, a packaging bag composed of a laminated film in which a base material sheet made of a resin film or paper and a sealant film are laminated is widely used. Has been. In addition, in order to suppress deterioration of the contents due to oxygen, reduction due to external diffusion of contents, etc., the gas barrier film is further laminated, or the gas barrier property is imparted to the base sheet, thereby improving the permeability of the laminated film. It is decreasing.

  On the other hand, the contents (especially medicinal ingredients, fragrance ingredients, etc.) are adsorbed or absorbed by the sealant film (especially polyolefin film, etc.) in contact with the contents, which reduces the amount of the contents or degrades the quality. (For example, refer to JP, 2015-137130, A (patent documents 1)).

  In JP 2010-6985 (Patent Document 2), a structural unit derived from a dicyclopentadiene compound, a structural unit derived from a tetracyclododecene compound, and a structural unit derived from a norbornene compound are included at a specific ratio. The hydrogenated product of the ring-opening copolymer contains excellent solution stability during production, and the molding material containing this hydrogenated product as a resin component has high transparency, high moisture resistance, and appropriate heat resistance. Is disclosed.

JP2015-137130A JP 2010-6985 A

  Medicinal components such as EVOH (ethylene / vinyl alcohol copolymer resin), PET (polyethylene terephthalate) resin, polyacrylonitrile (PAN), etc., as materials for the sealant film to suppress the adsorption or absorption of the contents to the sealant film The use of a low-adsorbing material that is difficult to adsorb or absorb contents such as aroma components has been studied. However, these materials have a problem of insufficient seal strength.

  Therefore, the present inventors examined a sealant film having excellent low adsorptivity and sufficient sealing strength. As a result, it has been found that it is effective to use a laminated film of a polyolefin layer and a polycycloolefin layer containing a specific polycycloolefin as a main component as a sealant film. The applicant of the present application has already filed a patent application (Japanese Patent Application No. 2006-142373) for such a sealant film.

  As a result of further investigation, this sealant film is discolored (yellowing, bluish discoloration, etc.), odor (ethylene gas) by γ-ray sterilization (γ-ray irradiation) of the contents when used as a packaging bag. It has been found that changes in physical properties such as odor may occur.

  The present invention has been made in view of the above problems, and an object thereof is to provide a sealant film that is excellent in low adsorptivity, has a sufficient seal strength, and suppresses changes in physical properties due to γ-ray irradiation. And

[1]
A polyolefin layer comprising a polyolefin;
A sealant film comprising a polycycloolefin layer containing polycycloolefin as a main component as an outermost layer,
The polycycloolefin is selected from a structural unit (A) derived from a dicyclopentadiene compound, a structural unit (B) derived from a tetracyclododecene compound, and a structural unit (C) derived from a norbornene compound. Including more than one structural unit,
The glass transition temperature of the polycycloolefin is 80 ° C. or less,
The polyolefin layer has a thickness of 10 μm or more and 40 μm or less,
A sealant film, wherein the polycycloolefin layer has a thickness of 5 µm to 20 µm.

[2]
The polycycloolefin includes a structural unit (A) derived from a dicyclopentadiene compound, a structural unit (B) derived from a tetracyclododecene compound, and a structural unit (C) derived from a norbornene compound [1 ] The sealant film as described in.

[3]
The sealant film according to [1] or [2], wherein the polycycloolefin has a glass transition temperature of 40 ° C or higher.

[4]
The dicyclopentadiene compound is tricyclo [5.2.1.0 ^2,6 ] deca-3,8-diene (synonymous with dicyclopentadiene) or a derivative thereof, and the tetracyclododecene compound is tetracyclo [ 4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene or a derivative thereof, and the norbornene-based compound is bicyclo [2.2.1] hept-2-ene or a derivative thereof, according to any one of [1] to [3] The sealant film as described.

[5]
The polycycloolefin is a ring-opening metathesis polymer of two or more compounds selected from the dicyclopentadiene compound, the tetracyclododecene compound and the norbornene compound, and has a carbon-carbon double bond. The sealant film according to any one of [1] to [4], which is hydrogenated.

[6]
The said polyolefin layer is a sealant film in any one of [1]-[5] containing the said polycycloolefin of 50 mass% or less with respect to the mass of the said sealant film.

[7]
A base sheet;
A laminated film obtained by laminating the sealant film according to any one of [1] to [6].

[8]
Furthermore, the laminated film according to [7], wherein a gas barrier film is laminated between the base sheet and the sealant film.

[9]
The laminated film according to [7] or [8], wherein the thickness is 100 μm or less.

[10]
[7] A packaging bag formed by sealing the laminated film according to any one of [9] so that the sealant films are fused together.

  ADVANTAGE OF THE INVENTION According to this invention, the sealant film which is excellent in low adsorptivity, has sufficient sealing strength, and the physical property change by gamma ray irradiation was suppressed can be provided.

1 is a schematic cross-sectional view showing a sealant film of Embodiment 1. FIG. It is a schematic sectional drawing which shows the laminated | multilayer film of Embodiment 2. It is a schematic sectional drawing which shows the laminated film of Embodiment 3.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings, the same reference numerals represent the same or corresponding parts.

<Sealant film>
[Embodiment 1]
With reference to FIG. 1, the sealant film 1 of this embodiment is a sealant film which consists of two layers, a polyolefin layer 11 (base sheet side) and a polycycloolefin layer 12 (seal side).

(Polyolefin layer: base sheet side)
The polyolefin layer 11 contains polyolefin. In addition, content of polyolefin with respect to the whole quantity of the polyolefin layer 11 becomes like this. Preferably it is 50 mass% or more, More preferably, it is 80 mass% or more, More preferably, it is 90 mass% or more.

  As the polyolefin, polyethylene can be suitably used. As polyethylene, for example, low density polyethylene (LDPE), linear low density polyethylene (LLDPE) and the like can be suitably used.

  The polyolefin layer may contain materials other than polyolefin. Examples of other materials include polycycloolefins similar to the main components of the polycycloolefin layer described below. The polycycloolefin contained in the polyolefin layer is preferably the same polycycloolefin as the polycycloolefin that is the main component of the polycycloolefin layer.

  When the polyolefin layer contains polycycloolefin, the mass of the polycycloolefin contained in the polyolefin layer 11 is 50 mass with respect to the mass of the entire sealant film 1 (the total of the polyolefin layer 11 and the polycycloolefin layer 12). % Or less is preferable. This is because when the mass of the polycycloolefin exceeds 50% by mass, a bluish discoloration may occur due to gamma ray irradiation.

(Polycycloolefin layer: seal side)
The polycycloolefin layer 12 contains polycycloolefin as a main component. Note that “include as a main component” means, for example, that the content of polycycloolefin is more than 50% by mass with respect to the total amount of the polycycloolefin layer 12, and the content of polyolefin is preferably 80% by mass. As mentioned above, More preferably, it is 90 mass% or more. Moreover, you may mix | blend other polymeric materials, various additives, etc. which are disclosed by patent document 2. FIG.

  The polycycloolefin includes structural units derived from two or more compounds (cycloolefin monomers) selected from dicyclopentadiene compounds, tetracyclododecene compounds, and norbornene compounds. That is, the polycycloolefin is selected from a structural unit (A) derived from a dicyclopentadiene compound, a structural unit (B) derived from a tetracyclododecene compound, and a structural unit (C) derived from a norbornene compound. Contains two or more structural units.

  Preferably, the polycycloolefin includes a structural unit (A) derived from a dicyclopentadiene compound, a structural unit (B) derived from a tetracyclododecene compound, and a structural unit (C) derived from a norbornene compound.

  When the polycycloolefin contains the structural units (A), (B) and (C), the ratio of the structural unit (A) derived from the dicyclopentadiene compound is preferably 5 to 80 mol%. The ratio of the structural unit (B) derived from the tetracyclododecene compound is preferably 10 to 90 mol%. The ratio of the structural unit (C) derived from the norbornene compound is preferably 5 to 50 mol%. In addition, these ratios are ratios when the sum of the structural units (A), (B), and (C) is 100 mol%. Even in this case, the polycycloolefin may contain a structural unit other than the structural units (A), (B) and (C) as long as the effects of the present invention are not impaired.

Examples of the dicyclopentadiene compound include dicyclopentadiene (tricyclo [5.2.1.0 ^2,6 ] deca-3,8-diene) and derivatives thereof. Examples of the dicyclopentadiene derivative include 2-methyldicyclopentadiene, 2,3-dimethyldicyclopentadiene, and 2,3-dihydroxydicyclopentadiene.

  In addition, examples of the structural unit (A) derived from a dicyclopentadiene compound include a structural unit derived from dicyclopentadiene.

Examples of the tetracyclododecene compound include tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene and its derivatives. Tetracyclo [4.4.0.1 ^2,5 . As a derivative of 1 ^7,10 ] -3-dodecene, for example, 8-methyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene, 8-ethyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene, 8-ethylidenetetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene, 8,9-dimethyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene, 8-ethyl-9-methyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene, 8-ethylidene-9-methyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene, 8-methyl-8-carboxymethyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene and the like.

Moreover, as a structural unit (B) derived from a tetracyclododecene compound, for example, tetracyclo [4.4.0.1 ^2,5 . And a structural unit derived from 1 ^7,10 ] -3-dodecene.

  Examples of the norbornene-based compound include bicyclo [2.2.1] hept-2-ene (common name: norbornene) and derivatives thereof. Examples of the derivatives of bicyclo [2.2.1] hept-2-ene include 5-methyl-bicyclo [2.2.1] hept-2-ene and 5,5-dimethyl-bicyclo [2.2. 1] Hept-2-ene, 5-ethyl-bicyclo [2.2.1] hept-2-ene, 5-ethylidene-bicyclo [2.2.1] hept-2-ene, 5-vinyl-bicyclo [ 2.2.1] hept-2-ene, 5-propenylbicyclo [2.2.1] hept-2-ene, 5-methoxycarbonyl-bicyclo [2.2.1] hept-2-ene, 5- And cyanobicyclo [2.2.1] hept-2-ene, 5-methyl-5methoxycarbonyl-bicyclo [2.2.1] hept-2-ene, and the like.

  In addition, examples of the structural unit (C) derived from the norbornene compound include a structural unit derived from bicyclo [2.2.1] hept-2-ene.

  The polycycloolefin is preferably obtained by ring-opening metathesis copolymerization of the above cycloolefin monomer and then hydrogenating the C—C double bond. Such a polycycloolefin can be produced based on Patent Document 2.

  The glass transition temperature (Tg) of the polycycloolefin is 80 ° C. or lower, preferably 75 ° C. or lower. In this case, it is possible to obtain a sealant film having appropriate seal strength and low-temperature sealability in addition to non-adsorbability. Tg can be measured based on JIS K7121.

  In addition, since there exists a possibility that a sealant film may fuse | melt when Tg of polycycloolefin becomes the same as room temperature, Tg of polycycloolefin becomes like this. Preferably it is 40 degreeC or more, More preferably, it is 50 degreeC or more.

  The sealant film 1 can be produced, for example, as a film having a two-layer structure by coextruding the above-described polyolefin layer (film-shaped semi-molded product) and polycycloolefin layer (film-shaped semi-molded product). . The thickness of the sealant film 1 is preferably 100 μm or less. The thickness of the sealant film 1 is preferably 10 μm or more.

  The sealant film 1 of the present embodiment includes a layer composed of a polycycloolefin containing a structural unit derived from two or more kinds of specific cycloolefin monomers as described above, so that the contents (medicinal components, aroma components) Or the like) and is sufficiently non-adsorptive with sufficient sealing strength.

  Regarding the seal strength, specifically, the seal strength of the sealant film is preferably 5.0 N / 15 mm or more under seal conditions of 140 ° C., 0.2 MPa, and 1.0 second. The seal strength is measured according to JIS Z0238.

  In the present embodiment, the polyolefin layer 11 has a thickness of 10 μm or more and 40 μm or less. Moreover, the thickness of the polycycloolefin layer 12 is 5 μm or more and 20 μm or less. By designing the thickness of the polyolefin layer 11 and the thickness of the polycycloolefin layer 12 in such a range, the sealant film 1 in which changes in physical properties due to γ-ray irradiation are suppressed can be obtained. Examples of changes in physical properties due to γ-ray irradiation include discoloration (yellowing or bluish discoloration), generation of odor (ethylene gas odor, etc.), and the like.

  The thickness of each layer (the polyolefin layer 11 and the polycycloolefin layer 12) can be measured with a microscope scale by observing the cut surface with a microscope after cutting the sealant film with a cutter or the like.

  In addition, the polyolefin layer 11 which comprises the sealant film 1 has a role which makes a film flexible. If the polycycloolefin layer 12 comprising a ring-opening metathesis polymer of two or more compounds selected from dicyclopentadiene compounds, tetracyclododecene compounds and norbornene compounds is a single layer, the film is hard and corona treatment Film formation is difficult, and it is very difficult to manufacture as a packaging bag. Therefore, by using the polyolefin layer 11 adjacent to the polycycloolefin layer 12, it has become possible to manufacture as a packaging bag by improving processability and film forming suitability.

  Moreover, the sealant film of the present embodiment also has a low temperature sealing property. Specifically, for example, the rising temperature of the seal strength of the sealant film (an index of the lowest temperature that can be sealed) is preferably 120 ° C. or less with regard to the low temperature sealability. The rising temperature of the seal strength is measured according to JIS Z0238, taking the temperature as a level.

Moreover, the sealant film of the present embodiment is also excellent in moisture resistance. Regarding moisture resistance, specifically, the water vapor permeability of a laminated film having a thickness of 50 μm or less formed by laminating a sealant film and a non-barrier substrate sheet is 5.0 g / (m ² · 24 h) or less. It is preferable. The moisture permeability (water vapor permeability) is measured under the conditions of 40 ° C. and 90% RH based on JIS K7129A.

<Laminated film>
[Embodiment 2]
With reference to FIG. 2, the laminated film 2 (packaging material) of the present embodiment is a laminated film in which the sealant film 1, the adhesive layer 41, and the base sheet 31 of the first embodiment are laminated in this order. is there. The thickness of the laminated film is preferably 100 μm or less.

  The base sheet 31 is not particularly limited as long as it has mechanical strength and dimensional stability, but a plastic film, paper, nonwoven fabric, and the like can be used. Examples of the constituent material of the plastic film include polyesters such as polyethylene terephthalate (PET) and polyethylene naphthalate, polyolefins such as polypropylene, polyamides such as polystyrene and 6-nylon, polycarbonate, polyacrylonitrile, and polyimide. The plastic film is preferably a biaxially stretched film. In the present embodiment, the base sheet 31 is a PET film.

  Although it does not specifically limit as an adhesive agent which comprises the contact bonding layer 41, The adhesive agent for dry lamination can be used suitably. Adhesives for dry lamination include two-component curable urethane adhesives, polyester urethane adhesives, polyether urethane adhesives, acrylic adhesives, polyester adhesives, polyamide adhesives, epoxy adhesives, etc. Is mentioned. In addition, as a method of bonding the sealant film 1 and the gas barrier film 6 using such an adhesive, a dry laminating method may be mentioned.

  Among the above adhesives, a two-component curable adhesive that does not easily lower the adhesive force due to excellent adhesive force and chemical components of the contents can be suitably used. The two-component curable adhesive is composed of a main agent and a curing agent, and examples thereof include a two-component curable adhesive composed of a polyester polyol and a polyfunctional polyisocyanate.

  In place of the above adhesive layer, an anchor coat agent (two-component curable urethane adhesive, polyallylamine, etc.) may be used.

  By providing the sealant film of Embodiment 1, the laminated film of this embodiment is a non-adsorptive film in which the adsorption or absorption of the contents (medicinal components, aroma components, etc.) is suppressed as in Embodiment 1. In addition, it has sufficient sealing strength and the like, and the physical property change due to γ-ray sterilization is suppressed.

[Embodiment 3]
Referring to FIG. 3, in the laminated film of the present embodiment, a gas barrier film 6 is laminated in the middle in order to suppress deterioration of the contents due to oxygen gas, reduction due to external diffusion of the contents, and the like. Except this point, the second embodiment is the same as the second embodiment. Note that an adhesive layer 42 for adhering the gas barrier film 6 such as an aluminum foil to the sealant film 1 is provided.

  Examples of the gas barrier film 6 include an aluminum foil. In addition, a film having an aluminum vapor deposition film, a film having an inorganic oxide vapor deposition film, or the like can be used. Specifically, for example, a film obtained by forming an aluminum vapor deposition film or an inorganic oxide vapor deposition film on a stretched film such as a polyester film, a polypropylene film, or a nylon film can be used. As the gas barrier film 6, an ethylene / vinyl alcohol copolymer film can also be used.

  As the adhesive constituting the adhesive layer 42, the same material as the adhesive layer 41 can be used. The adhesive constituting the adhesive layer 41 and the adhesive constituting the adhesive layer 42 may be the same component or different components.

<Packaging bag>
Using the laminated film formed as described above, a bag is formed into a desired shape to form a packaging bag. For example, if a pillow type packaging bag, a caseette type packaging bag, a self-supporting type packaging bag, etc. (see Patent Document 1) are prepared according to the purpose (packaging bag design, internal capacity, ease of use, etc.) Good. In such a packaging bag, at least two of the above laminated films are sealed at least partially so that the sealant films are fused together.

  Examples of the contents include pharmaceuticals, quasi drugs, foods, and beverages. The packaging bag of the present embodiment is particularly about contents containing medicinal components, aromatic components, etc. (components that are easily adsorbed or absorbed in the packaging bag, or components that are problematically adsorbed or absorbed in the packaging bag), It can be preferably used. Specifically, the packaging bag of the present embodiment is preferably used to store, for example, a transdermal absorbent or mouthwash containing medicinal ingredients, cosmetics containing aroma components such as fragrance, coffee, and the like. Can do.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated in detail, this invention is not limited to these.

(Examples 1-12, Comparative Examples 1-8)
Similarly to the third embodiment, the base material sheet 31, the gas barrier film 6, and the sealant film 1 of the first embodiment are laminated via a two-component curable polyester and polyurethane adhesive. The laminated film 2 of Examples 1-8 was produced.

  The base sheet 31 is made of polyethylene terephthalate (PET). The gas barrier film 6 is an aluminum foil. The thickness of the base material sheet 31 is 12 μm, and the thickness of the gas barrier film 6 is 7 μm.

  The sealant film 1 includes a polyolefin layer 11 and a polycycloolefin layer 12. The thickness of the polyolefin layer 11 and the thickness of the polycycloolefin layer 12 are as shown in Table 1.

  In Examples 1 to 10 and Comparative Examples 1 to 7, the polyolefin (PO) layer is made of linear low density polyethylene (LLDPE). In Examples 11 and 12 and Comparative Example 8, the polyolefin layer is composed of LLDPE and the following polycycloolefin A. In Examples 11 and 12 and Comparative Example 8, the content of polycycloolefin (PCO) relative to the total mass of the sealant film 1 is 50, 30, and 60% by mass, respectively.

In Examples 1 to 12 and Comparative Examples 1 to 8, the polycycloolefin (PCO) layer is composed of the following polycycloolefin A.
Polycycloolefin A:
Tricyclo [5.2.1.0 ^2,6 ] deca-3,8-diene,
Tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene, and
It is a terpolymer of three types of cycloolefin monomers consisting of bicyclo [2.2.1] hept-2-ene, and these cycloolefin monomers are subjected to ring-opening metathesis copolymerization, and then a C—C double bond It can be obtained by hydrogenating.

<Evaluation test>
About the said Examples 1-12 and Comparative Examples 1-8, the following evaluation tests were done before and after gamma ray irradiation. The irradiation amount of γ rays was 15 kGy, which is the irradiation amount during general γ ray sterilization.

(Evaluation Test 1)
As an evaluation test 1, evaluation by colorimetry was performed.

  Specifically, for each of the laminated films of Examples 1 to 12 and Comparative Examples 1 to 8, using a colorimeter ("X-Rite": Videojet X-Rite Co., Ltd.), L value and a value And b values were measured. The measurement results are shown in Table 1.

(Evaluation test 2)
As the evaluation test 2, “seal strength” was evaluated.

  Specifically, each laminated film of Examples 1-12 and Comparative Examples 1-8 was sealed with the sealant film inside. The sealing conditions were a sealing temperature of 170 ° C., a sealing pressure of 0.2 MPa, and a sealing time of 1.0 second. The peel strength (seal strength) of the laminated films cut into strips was measured based on JIS Z0238 for the peel strength (N / 15 mm) of the two laminated films sealed. The seal strength was measured at a place where the seal strength curve was stable.

(Evaluation Test 3)
As the evaluation test 3, “lamination strength” was evaluated.

  Specifically, the laminate strength between the sealant film and the aluminum foil was measured for each of the laminated films of Examples 1 to 12 and Comparative Examples 1 to 8.

  The results of the above evaluation tests 1 to 3 are shown in Table 1. In the rightmost “evaluation” column of Table 1, “◯” indicates that there was no change in physical properties due to γ-ray irradiation, and “×” indicates that a change in physical properties due to γ-ray irradiation occurred. Indicates that it has been determined. Further, in the “Remarks” column, the contents of physical property changes due to γ-ray irradiation are described including evaluations other than the evaluation tests 1 to 3 described above.

  In addition, about the polycycloolefin layer used for Examples 1-12 and Comparative Examples 1-8, the glass transition temperature (Tg) measured based on JISK7121 using the differential scanning calorimetry analyzer was 70 degreeC. It was.

  As can be seen from Comparative Example 1, it can be seen that when there is no polycycloolefin (PCO) layer, yellowing, generation of odor, and the like occur due to γ-ray irradiation.

  In addition, according to the study by the present inventors, a polycycloolefin layer containing a polycycloolefin that is already a copolymer of two or more kinds of specific cycloolefin polymers and has a glass transition temperature (Tg) of 80 ° C. or less, The laminated films of Examples 1 to 12 using a sealant film that is a laminate with a polyolefin layer are excellent in non-adsorbability, have appropriate sealing strength and low-temperature sealing properties, and also have moisture resistance. I know that However, since the sealant film of Comparative Example 1 did not have a PCO layer, it was not non-adsorbing (low adsorbing).

  Further, in Comparative Examples 2 to 5 in which the thickness of the polyolefin (PO) layer 11 was 50 μm (over 40 μm), odor was generated by γ-ray irradiation. On the other hand, in Comparative Examples 6 and 7 in which the thickness of the PCO layer was 30 μm (over 20 μm), a bluish discoloration occurred due to γ-ray irradiation.

  In contrast, in Examples 1 to 10, in which the thickness of the polyolefin layer was 10 μm or more and 40 μm or less and the thickness of the polycycloolefin layer 12 was 5 μm or more and 20 μm or less, discoloration and generation of odor did not occur.

  Therefore, when the thickness of the polyolefin layer is 10 μm or more and 40 μm or less and the thickness of the polycycloolefin layer 12 is 5 μm or more and 20 μm or less, changes in physical properties (discoloration (discoloration (yellowing or discoloration))) and odor ( It is considered that the sealant film 1 in which generation of an ethylene gas odor or the like) is suppressed can be obtained.

  Further, when the polyolefin layer contains polycycloolefin, Comparative Example 8 in which the content of the polycycloolefin contained in the polyolefin layer is 60% by mass (over 50% by mass) with respect to the mass of the entire sealant film. In, a bluish discoloration occurred by γ-ray irradiation.

  On the other hand, in Examples 11 and 12 in which the content of the polycycloolefin contained in the polyolefin layer is 50 and 30% by mass (50% by mass or less) with respect to the mass of the entire sealant film, discoloration and odor The outbreak did not occur.

  Therefore, when the polyolefin layer contains polycycloolefin, it is considered that the mass of the polycycloolefin contained in the polyolefin layer is preferably 50% by mass or less with respect to the mass of the entire sealant film.

  It should be understood that the embodiments and examples disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  The sealant film of the present invention can be used as the innermost layer of a laminated film constituting a packaging bag.

  DESCRIPTION OF SYMBOLS 1 Sealant film, 11 Polyolefin layer, 12 Polycycloolefin layer, 2 Laminate film, 31 Base material sheet, 41, 42 Adhesive layer, 6 Gas barrier film.

Claims (10)

A polyolefin layer comprising a polyolefin;
A sealant film comprising a polycycloolefin layer containing polycycloolefin as a main component as an outermost layer,
The polycycloolefin is selected from a structural unit (A) derived from a dicyclopentadiene compound, a structural unit (B) derived from a tetracyclododecene compound, and a structural unit (C) derived from a norbornene compound. Including more than one structural unit,
The glass transition temperature of the polycycloolefin is 80 ° C. or less,
The polyolefin layer has a thickness of 10 μm or more and 40 μm or less,
A sealant film, wherein the polycycloolefin layer has a thickness of 5 µm to 20 µm.   The polycycloolefin includes a structural unit (A) derived from a dicyclopentadiene compound, a structural unit (B) derived from a tetracyclododecene compound, and a structural unit (C) derived from a norbornene compound. The sealant film according to 1.   The sealant film according to claim 1 or 2, wherein the polycycloolefin has a glass transition temperature of 40 ° C or higher. The dicyclopentadiene compound is tricyclo [5.2.1.0 ^2,6 ] deca-3,8-diene or a derivative thereof, and the tetracyclododecene compound is tetracyclo [4.4.0.1. ^2,5 . 1, ¹⁰ ] -3-dodecene or a derivative thereof, wherein the norbornene-based compound is bicyclo [2.2.1] hept-2-ene or a derivative thereof. The sealant film as described.   The polycycloolefin is a ring-opening metathesis polymer of two or more compounds selected from the dicyclopentadiene compound, the tetracyclododecene compound and the norbornene compound, and has a carbon-carbon double bond. The sealant film according to any one of claims 1 to 4, which is hydrogenated.   The sealant film according to claim 1, wherein the polyolefin layer contains 50% by mass or less of the polycycloolefin with respect to the mass of the sealant film. A base sheet;
The laminated film formed by laminating | stacking the sealant film of any one of Claims 1-6.   Furthermore, the laminated | multilayer film of Claim 7 formed by laminating | stacking a gas barrier film between the said base material sheet and the said sealant film.   The laminated film according to claim 7 or 8, wherein the thickness is 100 µm or less.   A packaging bag formed by sealing the laminated film according to any one of claims 7 to 9 so that the sealant films are fused.

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