JP6172398B2 - Multilayer film, laminated film for packaging material, packaging bag and standing pouch - Google Patents

Description

  The present invention relates to a multilayer film used for packaging and filling liquid-containing materials such as foods, cosmetics and pharmaceuticals, a packaging material comprising the multilayer film, and a standing pouch.

  Conventionally, a multilayer film using a polyolefin-based resin as a seal layer or the like has been used for packaging food or cosmetics. Polyolefin resin is easy to adsorb organic compounds although it is easy to obtain high sealing strength by heat sealing, so multilayer films using polyolefin resin as a sealing layer are applied to packaging materials containing organic compounds as active ingredients Then, there existed a problem that the active ingredient of the said content reduced.

  As a packaging material that suppresses the adsorption of such active ingredients, a packaging material that uses a multilayer body having a cyclic polyolefin resin layer between polyolefin resin layers is disclosed (see Patent Document 1).

JP 2012-111538 A

  It is disclosed that the packaging material has good sealing strength and low adsorptivity by using a multilayer body having a cyclic polyolefin resin layer between polyolefin resin layers. However, in the fields of foods, cosmetics, pharmaceuticals, etc., further improvement in low adsorption performance has been required for practical use. As packaging containers, self-standing bags (standing pouches) that are lighter than conventional bottles and cans and have excellent volume reduction after use have become widespread. The film material constituting the standing pouch is required to have a sealing strength after filling the contents and a low adsorptivity of active ingredients contained in the contents.

  The present invention is intended to solve the above-described problems, and an object thereof is to provide a multilayer film having suitable seal strength and excellent low adsorptivity, a packaging bag comprising the multilayer film, and a standing pouch. To do.

  Moreover, this invention makes it a subject to provide the multilayer film which has the suitable bag-proofing performance and straight cut property with the said subject.

  The present invention is a multilayer film having a sealing layer containing a polyolefin resin as a main component on one surface layer, and a resin layer containing a cyclic polyolefin resin as a main component directly laminated on the sealing layer. A cyclic polyolefin having a cyclic polyolefin resin content of 95% by mass or more in a resin component contained in a resin layer containing a polyolefin resin as a main component, and having a glass transition temperature of 130 ° C. or less in the cyclic polyolefin resin. The above-described problems are solved by a multilayer film containing 40% by mass or more of a resin.

  The multilayer film of the present invention can realize suitable seal strength and excellent low adsorptivity by the above-described configuration, so that it can be used for packaging liquid contents containing active ingredients such as foods, cosmetics, and pharmaceuticals. The adsorption of the contents can be suitably suppressed, and can be suitably used in these fields.

  In addition, since a suitable bag-breaking performance can be imparted, it is superior in safety, excellent in straight cut property, and a good packaging bag is possible.

  The multilayer film of the present invention has a seal layer (A) whose main component is a polyolefin resin on one surface layer, and a resin layer (B) whose main component is a cyclic polyolefin resin on the seal layer (A). A directly laminated multilayer film, wherein the content of the cyclic polyolefin resin in the resin component contained in the resin layer (B) containing the cyclic polyolefin resin as a main component is 95% by mass or more, and the cyclic polyolefin It is a multilayer film containing 40% by mass or more of a cyclic polyolefin resin having a glass transition temperature of 130 ° C. or less in the system resin.

[Seal layer]
Examples of the polyolefin resin used for the seal layer (A) containing a polyolefin resin as a main component include polyethylene resins such as low density polyethylene (LDPE), linear low density polyethylene (LLDPE), and very low density polyethylene (VLDPE). , Ethylene-vinyl acetate copolymer (EVA), ethylene-methyl methacrylate copolymer (EMMA), ethylene-ethyl acrylate copolymer (EEA), ethylene-methyl acrylate (EMA) copolymer, ethylene-ethyl acrylate -Ethylene copolymers such as maleic anhydride copolymer (E-EA-MAH), ethylene-acrylic acid copolymer (EAA), ethylene-methacrylic acid copolymer (EMAA); and ethylene-acrylic acid Copolymer ionomer, ethylene-methacrylic acid copolymer Include ionomers are alone, it may be used by mixing two or more kinds.

  Especially, the adhesiveness with the resin layer (B) mainly composed of cyclic polyolefin resin is high, and when coextruded with the layer, low density polyethylene (LDPE), linear low Polyethylene resins such as density polyethylene (LLDPE) and very low density polyethylene (VLDPE) are preferred.

  The LDPE may be a branched low density polyethylene obtained by a high pressure radical polymerization method, and is preferably a branched low density polyethylene obtained by homopolymerizing ethylene by a high pressure radical polymerization method.

  As LLDPE, an ethylene monomer is the main component by a low-pressure radical polymerization method using a single site catalyst, and an α-olefin such as butene-1, hexene-1, octene-1, 4-methylpentene is used as a comonomer. Those obtained by copolymerizing can be preferably used. As a comonomer content rate in LLDPE, it is preferable that it is the range of 0.5-20 mol%, and it is more preferable that it is the range of 1-18 mol%.

  Examples of the single-site catalyst include various single-site catalysts such as metallocene catalyst systems such as combinations of metallocene compounds of Group IV or V transition metals and organoaluminum compounds and / or ionic compounds. In addition, the single-site catalyst has a uniform active site, so the molecular weight distribution of the resulting resin is sharper than a multi-site catalyst with a non-uniform active site. This is preferable because a resin having physical properties excellent in stability of sealing strength and anti-blocking property can be obtained.

Range of preferred 0.900~0.965g / cm ³ density of the ethylene-based resin is 0.880~0.970g / cm ^3. If the density is within this range, it has moderate rigidity, excellent mechanical strength such as heat seal strength and pinhole resistance, and film film formability and extrusion suitability are improved. Moreover, it is preferable that melting | fusing point is generally the range of 60-130 degreeC, and 70-120 degreeC is more preferable. When the melting point is within this range, the processing stability and the coextrusion processability with the layer (B) are improved, and further the flexibility is provided, so that the pinhole resistance is also improved. Moreover, it is preferable that it is 2-20 g / 10min, and, as for MFR (190 degreeC, 21.18N) of ethylene resin, it is more preferable that it is 3-10 g / 10min. When the MFR is within this range, the extrusion moldability of the film is improved.

  Examples of the propylene resin include propylene homopolymer, propylene / α-olefin random copolymer, such as propylene-ethylene copolymer, propylene-butene-1 copolymer, propylene-ethylene-butene-1 copolymer. Examples include coalesced metallocene catalyst polypropylene. These may be used alone or in combination. A propylene-α-olefin random copolymer is desirable, and a propylene-α-olefin random copolymer polymerized using a metallocene catalyst is particularly preferable.

  These polypropylene resins preferably have an MFR (230 ° C.) of 0.5 to 30.0 g / 10 min and a melting point of 110 to 165 ° C., more preferably an MFR (230 ° C.) of 2 0.0-15.0 g / 10 min, melting point is 115-162 ° C. If MFR and melting | fusing point are this range, the dimensional stability of the film obtained will be favorable and the film-forming property at the time of setting it as a film will also improve.

  The seal layer (A) mainly composed of a polyolefin resin used in the present invention may contain other components other than the polyolefin resin. As the other components, various resins that can be coextruded with the polyolefin resin can be used.

  The content of the polyolefin resin in the seal layer (A) containing the polyolefin resin as a main component is preferably 90% by mass or more, particularly preferably 95% by mass or more, substantially from the polyolefin resin. More preferably.

[Cyclic polyolefin resin layer]
The cyclic olefin-based resin of the resin layer (B) containing the cyclic polyolefin-based resin as a main component is not particularly limited in its structure. For example, a norbornene-based polymer, a vinyl alicyclic hydrocarbon polymer, And cyclic conjugated diene polymers. Among these, norbornene-based polymers are preferable. The norbornene-based polymer includes a ring-opening polymer of a norbornene-based monomer (hereinafter referred to as “COP”), a norbornene-based copolymer obtained by copolymerizing a norbornene-based monomer and an olefin such as ethylene (hereinafter, referred to as “COP”). , “COC”). Furthermore, COP and COC hydrogenates are particularly preferred. The weight average molecular weight of the cyclic olefin resin is preferably 5,000 to 500,000, more preferably 7,000 to 300,000.

  The norbornene monomer used as a raw material for the norbornene polymer is an alicyclic monomer having a norbornene ring. Examples of such norbornene-based monomers include norbornene, tetracyclododecene, ethylidene norbornene, vinyl norbornene, ethylidetetracyclododecene, dicyclopentadiene, dimethanotetrahydrofluorene, phenyl norbornene, methoxycarbonyl norbornene, methoxy And carbonyltetracyclododecene. These norbornene monomers may be used alone or in combination of two or more.

  Examples of the olefin used for the norbornene copolymer obtained by copolymerizing the norbornene monomer and a copolymerizable olefin include olefins having 2 to 20 carbon atoms such as ethylene, propylene, and 1-butene. A cycloolefin such as cyclobutene, cyclopentene or cyclohexene; a non-conjugated diene such as 1,4-hexadiene; These olefins can be used alone or in combination of two or more.

  In the resin layer (B) used for this invention, suitable low adsorption property and bag-breaking resistance are realizable by containing 95 mass% or more of cyclic polyolefin resin. Moreover, it becomes easy to obtain a suitable straight cut property. The content of the cyclic polyolefin resin is preferably 98% by mass or more of the resin layer (B), and more preferably a layer substantially made of a cyclic polyolefin resin.

  When the resin layer (B) contains other components than the cyclic polyolefin resin, various resins that can be co-extruded with the cyclic polyolefin resin can be used. For example, a polyolefin resin other than the cyclic polyolefin can be used. Can be used.

  Examples of commercially available products that can be used as the cyclic polyolefin-based resin include a ring-opening polymer (COP) of a norbornene-based monomer such as “ZEONOR” manufactured by Nippon Zeon Co., Ltd. Examples of the coalescence (COC) include “Appel” manufactured by Mitsui Chemicals, Inc. and “TOPAS” manufactured by Polyplastics.

  In the resin layer (B) used in the present invention, among these cyclic polyolefin resins, by using 40 mass% or more of a cyclic polyolefin resin having a glass transition temperature of 130 ° C. or less, low adsorptivity and suitable fracture resistance. Both bag performance and sealing strength can be achieved. When the cyclic olefin-based resin having a glass transition temperature of 130 ° C. or lower is contained in an amount of at least mass%, the interlayer strength with the resin layer (A) is improved, and a high sealing strength can be obtained.

  As the cyclic polyolefin resin having a glass transition temperature of 130 ° C. or lower, for example, an amorphous cyclic polyolefin resin having a norbornene monomer content of 75% by mass or less can be preferably used, and the monomer is more preferably used. Is a cyclic polyolefin resin having a content ratio of 70% by mass or less.

  Further, the glass transition temperature Tg of the resin layer (B) is preferably Tg of 200 ° C. or less from the viewpoint that it can be produced by a co-pushing lamination method and industrial raw material availability. . The temperature is particularly preferably 60 ° C to 180 ° C. As the resin layer (B) having such Tg, the content ratio of the norbornene monomer in the total amount of the cyclic polyolefin resin used in the resin layer (B) is in the range of 20 to 90% by mass. More preferably, it is 25-90 mass%, More preferably, it is 30-85 mass%. When the content ratio is within this range, the heat resistance, rigidity, moisture resistance, and processing stability are improved. In addition, the glass transition temperature Tg in this invention is a value obtained by measuring by DSC.

[Multilayer film]
The multilayer film of the present invention is a multilayer film in which the sealing layer (A) and the resin layer (B) are directly laminated. With this configuration, it is possible to achieve suitable seal strength and low adsorptivity.

  In the multilayer film of the present invention, other layers may be multilayered on the resin layer (B). As the other layer, for example, a resin layer (C) mainly composed of a polyolefin-based resin can be preferably exemplified. As the polyolefin resin, the polyolefin resin used for the sealing layer (A) can be preferably used, and among them, very low density polyethylene (VLDPE), linear low density polyethylene (LLDPE), and low density polyethylene (LDPE). The polyethylene resin such as can be preferably used. In particular, the packaging machine suitability is improved by multilayering the resin layer (A) and the resin layer (C) having a difference in melting point.

  In addition, content of the polyolefin-type resin in a resin layer (C) contains the said specific resin in 50 mass% or more with respect to the total mass of the resin component used in order to form the said resin layer (C). It is preferable that it contains 60% by mass or more. In the resin layer (C), other components than the polyolefin resin may be contained, and as the other components, various resins that can be coextruded with the polyolefin resin can be used.

  As described above, the multilayer film of the present invention is sufficient if at least the resin layer (A) and the resin layer (B) are included in the (A) / (B) configuration, and various layers are appropriately multilayered. Can be used. Especially, as the structure using the resin layer (C), it is easy to obtain suitable seal strength and excellent low adsorptivity, and it is easy to improve dimensional stability and film formability. Preferred examples include B) / (C), (A) / (B) / (C) / (B).

  The thickness of the multilayer film of the present invention is preferably in the range of 15 to 200 μm, particularly in the range of 30 to 150 μm, from the viewpoint of the balance between rigidity and low adsorptivity, sealability, and processability. preferable.

  In the multilayer film of the present invention, the thickness of the resin layer (A) is preferably 50 μm or less, more preferably 30 μm or less. By setting the thickness of the resin layer (A) to 50 μm, it becomes easy to obtain high sealing strength and suitable low adsorptivity.

  In the multilayer film of the present invention, the thickness of the resin layer (B) is preferably 50 μm or less, more preferably 30 μm or less. By setting the thickness of the resin layer (B) to 50 μm or less, the flexibility of the film can be easily obtained and high sealing strength can be easily obtained.

  When the resin layer (C) is used, the thickness of the resin layer (C) is preferably 150 μm or less, and 100 μm or less when the resin layer (C) such as packaging suitability is used. It is more preferable because it is easy to obtain the effect.

  In addition, although the said each layer may provide the same layer in multiple layers in a multilayer film, when providing the same layer in multiple layers, it is preferable to make the total thickness of each layer into the said range. In addition, the lower limit of the thickness of each layer is not particularly limited as long as the effect of the present invention is achieved, but each layer is preferably 3 μm or more, and more preferably 5 μm or more.

  For each of the resin layers (A), (B), and (C), an antifogging agent, an antistatic agent, a thermal stabilizer, a nucleating agent, an antioxidant, a lubricant, an antiblocking agent, Components such as a release agent, an ultraviolet absorber, and a colorant can be added within a range that does not impair the object of the present invention. In particular, it is possible to make the content opaque or white due to the concealability of the contents and the print appearance characteristics.

  In the multilayer film of the present invention, the surface of the outermost resin layer (B) or resin layer (C) is treated so that the surface tension of the outermost surface is 38 mN / m or more, preferably 40 mN / m or more. be able to. Examples of such treatment methods include corona treatment, plasma treatment, chromic acid treatment, flame treatment, hot air treatment, surface oxidation treatment such as ozone / ultraviolet treatment, and surface unevenness treatment such as sandblasting. Corona treatment is preferable. By performing such a surface treatment, when the post-process such as printing or aluminum vapor deposition is performed on the multilayer film, the coating property of the ink and the adhesive is improved, and the adhesion with the ink, the aluminum, the anchor coating agent and the like is improved. This makes it easy to avoid problems such as ink and vapor deposition aluminum dropping off and delamination.

  The method for producing the film used in the present invention is not particularly limited. For example, in the case of a multilayer structure, the resin or resin mixture used for each resin layer is heated and melted with a separate extruder, and a co-extrusion multilayer is used. Examples thereof include a coextrusion method in which a desired multilayer structure is formed in a molten state by a method such as a die method or a feed block method, and then formed into a film shape by inflation, a T-die / chill roll method, or the like. This coextrusion method is preferable because the thickness ratio of each layer can be adjusted relatively freely, and a multilayer film excellent in hygiene and cost performance can be obtained. In addition, when a resin layer (B) mainly composed of an amorphous cyclic polyolefin resin used in the present invention and a polyethylene resin as the resin layer (A) are used, the difference between the melting point and the Tg between the two. In some cases, the film appearance may deteriorate during coextrusion processing, and it may be difficult to form a uniform layer structure. In order to suppress such deterioration, a T-die / chill roll method that can perform melt extrusion at a relatively high temperature is preferable.

[Packaging materials]
The multilayer film of the present invention can be used alone or as a packaging material by laminating a substrate such as another film using the multilayer film of the present invention as a sealant. The packaging material has the sealing layer (A) in the multilayer film as one surface layer, processed into an appropriate mode, and heat-sealing the sealing layer (A) of one or more packaging materials. Various packaging bags can be formed.

  As a structural example of the laminated film for packaging materials using the multilayer film of the present invention (hereinafter referred to as multilayer film (1)), a structure in which the multilayer film (1) and the substrate (2) are laminated can be exemplified.

  Examples of the material constituting the base material (2) include polyamide resins such as nylon 6 and nylon 66, polyester resins such as polyethylene terephthalate and polybutylene terephthalate, polypropylene resins, polyethylene resins, cellophane, paper, paperboard, textiles, and aluminum. A foil etc. are mentioned, Preferably, it is a film or aluminum foil which consists of a polyamide resin, a polyester resin, or a polypropylene resin. When the substrate is a film made of polyamide resin, polyester resin or polypropylene resin, it is preferably a stretched film. Further, the substrate may be a single layer or a multilayer. Examples of the multilayer base material include a polyamide resin layer, an ethylene-vinyl alcohol copolymer resin layer, a three-layer base material that is multilayered in the order of the polyamide resin layer, and a base material in which a polyester resin layer and an aluminum foil are multilayered. It is done.

  Examples of a method for laminating the multilayer film (1) and the substrate (2) via an adhesive include known methods such as a dry laminating method, a wet laminating method, a sand laminating method, and a hot melt laminating method.

  Examples of the adhesive used to bond the multilayer film (1) and the base material (2) include adhesive resins such as two-component curable polyurethane adhesives, epoxy adhesives, and acid-modified olefin resin adhesives. Is mentioned.

  The laminated film for packaging material may have a layer other than the multilayer film (1) and the base material (2), and may have, for example, a barrier layer that prevents permeation of oxygen gas, water vapor, and the like. .

  Examples of the barrier layer include a vapor deposition layer of an inorganic oxide such as silicon oxide or aluminum oxide, a polyvinylidene chloride resin layer, a vinyl alcohol resin layer, an ethylene-vinyl alcohol copolymer layer, a polyacrylonitrile resin layer, and a polyamide system. Examples thereof include a resin layer. In particular, a vapor deposition layer of an inorganic oxide such as silicon oxide or aluminum oxide is preferably used as the barrier layer. The laminate of the present invention having an inorganic oxide vapor-deposited layer has an advantage of excellent storage stability of contents.

  The barrier layer is a method of depositing an inorganic oxide on one side of the substrate (2) by physical vapor deposition or chemical vapor deposition, or a coating method such as roll coating, gravure roll coating, kiss coating, Examples thereof include a method in which a barrier layer is formed by applying a solution in which a resin is dissolved by a printing method such as gravure printing, offset printing, or transfer printing.

  The laminated film for a packaging material laminated with a base material such as the above-mentioned other film can be suitably applied particularly to a standing pouch, and the standing pouch is formed by a method generally used in the past using the laminated film for a packaging material. Can be produced. For example, a bag can be made into a standing pouch by heat-sealing two side films and one bottom film.

  The multilayer film of the present invention can be used for various packaging materials such as standing pouches because it can realize suitable sealing strength and excellent low adsorptivity, and can be used for liquid contents containing active ingredients such as food, cosmetics, and pharmaceuticals. Even when used in packaging, the adsorption of the contents can be suitably suppressed, and can be suitably used in these fields.

  Next, the present invention will be described in more detail with reference to examples and comparative examples.

Example 1
As the resin for the resin layer (A), linear low density polyethylene [density: 0.920 g / cm ³ , MFR: 5 g / 10 min (190 ° C., 21.18 N); hereinafter referred to as “LLDPE1”. ] Was used. Further, as a resin for the resin layer (B), a ring-opening polymer of a norbornene-based monomer [“Appel APL8008T” manufactured by Mitsui Chemicals, Inc., MFR: 15 g / 10 min (260 ° C., 21.18 N), glass transition temperature: 70 ° C .; hereinafter referred to as “COC (1)”. 100 parts by mass were used. Further, as the resin for the resin layer (C), linear medium density polyethylene [density: 0.930 g / cm ³ , MFR: 5 g / 10 min (190 ° C., 21.18 N); hereinafter referred to as “LLDPE2”. ] Was used. These resins are supplied to an extruder for a resin layer (A) (caliber 50 mm), an extruder for a resin layer (B) (caliber 50 mm), and an extruder for a resin layer (C) (caliber 50 mm), respectively. The melted resin is melted at 230 ° C., and the melted resin is supplied to a T-die / chill roll co-extrusion multilayer film production apparatus (feed block and T-die temperature: 250 ° C.) having a feed block. A coextruded multilayer film (X1) having a three-layer structure of (A) / (B) / (C) and a thickness of each layer of 15 μm / 15 μm / 50 μm (total 80 μm) was obtained. The resin layer (C) was subjected to corona treatment, and the surface tension by the wetting reagent was 40 mN / m.

(Example 2)
As the resin for the resin layer (A), LLDPE1 is used, and as the resin for the resin layer (B), 70 parts by mass of COC (1) and a ring-opening polymer of norbornene-based monomer [“Apel APL6013T” manufactured by Mitsui Chemicals, Inc. MFR: 15 g / 10 min (260 ° C., 21.18 N), glass transition temperature: 125 ° C .; hereinafter referred to as “COC (2)”. 30 parts by mass of a resin mixture was used. Moreover, LLDPE2 was used as resin for resin layers (C). A coextruded multilayer film (X2) having a three-layer structure of (A) / (B) / (C) and a thickness of each layer of 15 μm / 15 μm / 50 μm (total 80 μm) was obtained. The resin layer (C) was subjected to corona treatment, and the surface tension by the wetting reagent was 40 mN / m.

(Example 3)
LLDPE1 was used as the resin for the resin layer (A), and 50 parts by mass of COC (1) and 50 parts by mass of COC (2) were used as the resin for the resin layer (B). Moreover, LLDPE2 was used as resin for resin layers (C). A co-extruded multilayer film (X3) having a three-layer structure of (A) / (B) / (C) and a thickness of each layer of 15 μm / 10 μm / 55 μm (total 80 μm) was obtained. The resin layer (C) was subjected to corona treatment, and the surface tension by the wetting reagent was 40 mN / m.

Example 4
As the resin for the resin layer (A), linear low-density polyethylene LLDPE1, and as the resin for the resin layer (B), a ring-opening polymer of 50 parts by mass of COC (1) and a norbornene-based monomer [“Apel” manufactured by Mitsui Chemicals, Inc. APL6015T ”, MFR: 10 g / 10 min (260 ° C., 21.18 N), glass transition temperature: 145 ° C .; hereinafter referred to as“ COC (3) ”. 50 parts by mass of a resin mixture was used. LLDPE2 was used as the resin for the resin layer (C). A co-extruded multilayer film (X4) having a three-layer structure (A) / (B) / (C) and a thickness of each layer of 15 μm / 10 μm / 55 μm (total 80 μm) was obtained. The resin layer (C) was subjected to corona treatment, and the surface tension by the wetting reagent was 40 mN / m.

(Example 5)
As the resin for the resin layer (A), linear medium density polyethylene LLDPE1, COC (1) as the resin for the resin layer (B), and LLDPE2 as the resin for the resin layer (C) were used. Co-extruded multilayer film (X5) in which the layer structure of the film is a four-layer structure of (A) / (B) / (C) / (B) and the thickness of each layer is 15 μm / 15 μm / 35 μm / 15 m (total 80 μm) ) The resin layer (B) as the outermost layer was subjected to corona treatment, and the surface tension by the wetting reagent was 40 mN / m.

(Example 6)
As a base material (1), using a bar coater on the corona-treated surface of “biaxially stretched nylon film 15 μm”, solvent-based laminating adhesive main agent Dick Dry LX-703VL (manufactured by DIC Graphics: polyester polyol) / An adhesive having a ratio of Takenate D-110N / ethyl acetate = 80/10/100 was applied, and an aluminum foil having a thickness of 7 μm was bonded through the adhesive. The coextruded multilayer film (X5) was bonded onto the aluminum foil of the substrate (1) through an adhesive to obtain a laminated film.

(Comparative Example 1)
As resin for resin layer (A), LLDPE1, as resin layer (C), LLDPE2, as resin for resin layer (B), 30 parts by mass of COC (1) and 70 parts by mass of COC (3) are used. It was. Coextruded multilayer film in the same manner as in Example 1 so that the layer structure of the film is a three-layer structure of (A) / (B) / (C), and the thickness of each layer is 15 μm / 20 μm / 45 μm (total 80 μm) (X6) was obtained.

(Comparative Example 2)
As resin for resin layer (A), LLDPE1, as resin layer (C), LLDPE2, as resin for resin layer (B), 50 parts by mass of COC (1) and 50 parts by mass of LLDPE (1) are used. It was. Co-extruded multilayer film in the same manner as in Example 1 so that the layer structure of the film is a three-layer structure of (A) / (B) / (C), and the thickness of each layer is 15 μm / 15 μm / 50 μm (total 80 μm) (X7) was obtained.

(Comparative Example 3)
A coextruded multilayer film (X8) was prepared in the same manner as in Comparative Example 2 except that 80 parts by mass of COC (1) and 20 parts by mass of LLDPE (1) were used as the resin for the resin layer (B). Obtained.

(Comparative Example 4)
As resin for resin layer (A), LLDPE1, as resin layer (C), LLDPE2, as resin for resin layer (B), 30 parts by mass of COC (1) and 70 parts by mass of COC (3) are used. It was. Coextruded multilayer film in the same manner as in Example 1 so that the layer structure of the film is a three-layer structure of (A) / (B) / (C), and the thickness of each layer is 15 μm / 20 μm / 45 μm (total 80 μm) (X10) was obtained. A laminated film was obtained in the same manner as in Example 6 using the obtained coextruded multilayer film (X9).

  The following evaluation was performed about the film obtained above. The obtained results are shown in the table.

[Seal strength]
The resin layers (A) not subjected to surface treatment were sealed under the conditions of a seal temperature of 170 ° C., a seal time of 0.1 S, and a seal pressure of 0.3 MPa. The sealed film was naturally cooled at 23 ° C., and then a sample was cut into a strip shape having a width of 15 mm. The cut sample was peeled 90 degrees at a rate of 300 mm / min using a tensile tester (manufactured by A & D Co., Ltd.) in a thermostatic chamber at 23 ° C. and 50% Rh, and the heat seal strength was measured. . From the value of the obtained heat seal strength, the heat seal strength was evaluated according to the following criteria.
○: Heat seal strength is 40 N / 15 mm width or more ×: Heat seal strength is less than 40 N / 15 mm width

[Adsorption]
A 12 × 12 (cm) size sachet was prepared, and a predetermined amount of methyl salicylate or menthol was sealed in the sachet, and the sachet weight over time was measured. The adsorptivity of the film was evaluated from the change in the weight of the sachet before and after the contents were enclosed.

[Straight straightness]
A 1 cm cut was made at a position 5 cm from the end in the MD direction on the film cut into a 10 cm square. The edge where the cut was made was taken as a side, and a mark was provided at a position 3 cm from the upper and lower sides on the other side of the side where the cut was made. The film was held with both hands near the left and right sides of the cut, and was torn along the cut. Similarly, a film having a cut in the TD direction was prepared on a film cut into a 10 cm square, the same evaluation was performed, and the following criteria were evaluated.
○: In both the MD direction and the TD direction, the tear end when tearing is inside the position 3 cm from the upper side and the lower side. ×: At least one of the MD direction and the TD direction is the upper end and the lower side when tearing. It is outside the position of 3cm from

  As is clear from the above table, the multilayer films of the present invention of Examples 1 to 6 can realize suitable sealing properties and low adsorptivity. On the other hand, the multilayer films of Comparative Examples 1 and 4 had a sealing strength, and the multilayer films of Comparative Examples 2 to 3 had insufficient low adsorptivity, making them difficult to put into practical use.

Claims (7)

A multilayer film used for a standing pouch,
One surface layer has a seal layer (A) mainly composed of a polyolefin-based resin, and a resin layer (B) mainly composed of a cyclic polyolefin-based resin is directly laminated on the seal layer (A),
On the resin layer (B) whose main component is the cyclic polyolefin resin, a resin layer made of a polyolefin resin (C) is provided.
On the olefin resin layer (C), the resin layer (B) is further included.
The content of the cyclic polyolefin resin in the resin component contained in the resin layer (B) containing the cyclic polyolefin resin as a main component is 95% by mass or more,
A multilayer film comprising 40% by mass or more of a cyclic polyolefin resin having a glass transition temperature of 130 ° C. or lower in the cyclic polyolefin resin.   The multilayer film according to claim 1, wherein the seal layer (A) has a thickness of 50 μm or less.   The multilayer film according to claim 1 or 2, wherein a thickness of the resin layer (B) containing the cyclic polyolefin resin as a main component is 50 µm or less. Seal layer under conditions of seal temperature 170 ° C, seal time 0.1S, seal pressure 0.3MPa (A) When sealing each other and peeling 90 degrees at 23 ° C., 50% Rh, 300 mm / min The heat seal strength of is 40 N / 15 mm width or more. Multilayer film. The other surface layer of the sealing layer (A) is a resin whose main component is the cyclic polyolefin resin. It is a fat layer (B), The multilayer film in any one of Claims 1-4. A laminated film for packaging material, wherein a base material is laminated on the other surface of the sealing layer (A) of the multilayer film according to any one of claims 1 to 5 . A standing pouch using the laminated film for packaging material according to claim 6 .