WO2020022106A1

WO2020022106A1 - Multilayer film and package

Info

Publication number: WO2020022106A1
Application number: PCT/JP2019/027680
Authority: WO
Inventors: 藤原　達也; 研太佐々木; 智大中田; 惇松本; 俊介越智
Original assignee: 住友ベークライト株式会社
Priority date: 2018-07-23
Filing date: 2019-07-12
Publication date: 2020-01-30
Also published as: TW202007531A; JP6659002B1; CN112313077A; JPWO2020022106A1

Abstract

The present invention is: a multilayer film (1) provided with at least a sealant layer (2) provided so as to be a surface layer, the sealant layer (2) including at least straight-chain low-density polyethylene, and the density of the straight-chain low-density polyethylene being 0.93 or greater; and a package provided with the multilayer film (1) and a sterilizing paper, at least a portion of the sealant layer (2) of the multilayer film (1) being heat-sealed to the surface of the sterilizing paper.

Description

Multilayer film and package

The present invention relates to a multilayer film and a package.
This application discloses Japanese Patent Application No. 2018-137395 filed in Japan on July 23, 2018, Japanese Patent Application No. 2019-40869 filed in Japan on March 6, 2019, and July 2, 2019. Priority is claimed based on Japanese Patent Application No. 2019-123818 filed in Japan, the contents of which are incorporated herein by reference.

In recent years, deep-drawn packages (hereinafter also referred to as “deep-drawn packages”) have been used as medical packages. The deep-drawing package has a bottom material composed of a multilayer film having a concave portion formed in the center and a lid material composed of a nonwoven fabric made of polyethylene or sterilized paper (hereinafter, also referred to as a “nonwoven fabric made of PE”). Are joined by And the gauze for business use, a cotton swab, a medical instrument, etc. are stored in the above-mentioned crevice.

Conventionally, as a bottom material used for a medical package, a multilayer film in which a polyester film or a nylon film and a heat-sealable resin film are laminated (lamination method) is widely and generally used. On the other hand, as described above, a nonwoven fabric made of polyethylene or sterilized paper is used as described above from the viewpoint of air permeability of a sterilizing gas in a sterilizing process.

By the way, the medical packaging is required to be easily openable depending on the mode of use. As the lid material of the medical package, a polyethylene nonwoven fabric is selected from the viewpoint that hygiene is emphasized. Since the polyethylene nonwoven fabric coated with an adhesive and imparted easy-opening properties is expensive and the gas permeability is reduced, the easy peeling function is provided to the side of the multilayer film sealed with the polyethylene nonwoven fabric. A structure in which an easily peelable resin layer (hereinafter, also referred to as an “easy peel layer”) is provided on a sealing side with a nonwoven fabric made of PE or the like as a multilayer film used as a bottom material in order to impart easy-opening properties to a medical package. Is known (Patent Document 1). Also known is a co-extruded multilayer film for deep drawing, comprising a polyamide resin, a nonwoven fabric or sterilized paper made of polyethylene at 135 ° C. or less and a seal layer capable of heat sealing with a seal layer, and an easy peel layer having delamination property with the seal layer. (Patent Document 2).

JP 2014-162162 A JP 2014-19006 A

A multilayer film as a bottom material used for a medical package requires a proper sealing strength when heat-sealing with sterilized paper as a lid material. If a part of the sterilized paper remains on the medical device, the so-called paper residue occurs, paper fibers may adhere to the medical instruments etc. stored in the medical package and enter the body, Hygiene problems such as lowering occur.

The present invention has been made in view of the above circumstances, and when heat-sealed with sterilized paper, while ensuring an appropriate sealing strength, a multilayer film that can be used as a bottom material that does not generate paper residue on the peeled surface, and It is an object to provide a package.

In order to achieve the above object, the present invention employs the following configurations.
[1] At least a sealant layer provided to be a surface layer,
A multilayer film, wherein the sealant layer contains at least linear low-density polyethylene, and the linear low-density polyethylene has a density of 0.93 or more.
[2] The sealant according to [1], wherein the sealant layer further contains low-density polyethylene, and a mass ratio of the linear low-density polyethylene to the low-density polyethylene is in a range of 50:50 to 99: 1. The multilayer film according to the above.
[3] The multilayer film according to [1] or [2], which is provided so as to be adjacent to the sealant layer and includes a base layer containing a polyethylene resin.
[4] The multilayer film according to [3], wherein the base material layer includes a linear low-density polyethylene.
[5] The multilayer film according to [3] or [4], wherein the thickness ratio of the sealant layer to the base material layer is in the range of 1: 0.5 to 1:15.
[6] The multilayer film according to any one of [1] to [5], wherein the low-molecular-weight volatile component of the linear low-density polyethylene contained in the sealant layer is 0.1% by weight or less.
[7] The molecular weight distribution (Mw / Mn) of the linear low density polyethylene contained in the sealant layer is 7.0 or less, and the number average molecular weight Mn of the linear low density polyethylene is 20,000 or more. And the multilayer film according to any one of [1] to [6].
[8] The multilayer film according to any one of [1] to [7], which can be heat-sealed with sterilized paper in a temperature range of 135 to 155 ° C.
[9] The multilayer film according to any one of [1] to [8], and sterilized paper,
A package wherein at least a part of the sealant layer of the multilayer film is heat-sealed to the surface of the sterilized paper.
[10] The package according to [9], wherein a seal strength between the multilayer film and the sterilized paper is 1.0 to 7.7 (N / 15 mm).

As described above, the multilayer film of the present invention includes at least a sealant layer provided to be a surface layer, wherein the sealant layer contains at least linear low-density polyethylene, and Since the density of the low-density polyethylene is 0.93 or more, the package in which the multilayer film and the sterilized paper are heat-sealed, when the sterilized paper is peeled off while ensuring appropriate sealing strength, the bottom material is peeled off. This has an excellent effect that it is possible to suppress the occurrence of so-called paper residue, which is a part of the sterilized paper remaining on the surface, and to provide a package having no hygiene problems.

BRIEF DESCRIPTION OF THE DRAWINGS It is a cross-sectional schematic diagram of the multilayer film 1 which is one Embodiment to which this invention is applied. BRIEF DESCRIPTION OF THE DRAWINGS It is a cross-sectional schematic diagram of the multilayer film 1 which is one Embodiment to which this invention is applied.

Hereinafter, a multilayer film and a package according to an embodiment of the present invention will be described in detail. In addition, in the drawings used in the following description, in order to make the characteristics easy to understand, the characteristic portions may be enlarged for convenience, and the dimensional ratios and the like of the respective components are not necessarily the same as the actual ones. Absent.

<Multilayer film>
First, the configuration of a multilayer film according to an embodiment of the present invention will be described. FIG. 1 is a schematic cross-sectional view of a multilayer film 1 according to an embodiment to which the present invention is applied. As shown in FIG. 1, a multilayer film 1 of the present embodiment has a schematic configuration including a sealant layer 2 provided as a surface layer, and a base material layer 3 provided adjacent to the sealant layer 2. ing. Further, as shown in FIG. 2, the multilayer film 1 of the present embodiment includes a sealant layer 2 provided as a surface layer, a base layer 3 provided adjacent to the sealant layer 2, and a base layer 3. It may be schematically configured to include another resin layer laminated thereon. The multilayer film 1 of the present embodiment can be used as a film for a package, particularly for a bottom material of a medical package.

(Sealant layer)
The sealant layer 2 is a resin layer provided to be joined to sterilized paper to be joined by heat sealing and to provide easy-openability. The sealant layer 2 contains at least linear low-density polyethylene, and the linear low-density polyethylene has a density of 0.93 or more, preferably 0.93 or more and 0.98 or less, more preferably 0.93 or more. 0.95 or less. When the density of the linear low-density polyethylene is equal to or higher than the lower limit of the above range, sterilized paper, heat sealing with an appropriate seal strength is possible, and when the sterilized paper is peeled, paper The occurrence of the remainder can be suppressed. On the other hand, when it is below the upper limit of the above range, heat sealing with sterilized paper becomes easy.

The resin that can be used for the sealant layer 2 is not particularly limited as long as it is a resin containing linear low-density polyethylene (LLDPE) having the above density, but includes a metallocene-catalyzed linear low-density polyethylene (mLLDPE). Resins are preferred.
As the linear low-density polyethylene (LLDPE) having the above density, a resin having a low detection amount of a low-molecular-weight volatile component by GC-MS is preferable. If the low-molecular-weight volatile component is small, no gas is generated during molding, and equipment contamination can be prevented. The detection amount of the low molecular weight volatile component is preferably 0.1 wt% or less, and more preferably 0.05 wt% or less.
The linear low-density polyethylene (LLDPE) having the above density is preferably a resin having a low molecular weight component content in the molecular weight distribution (Mw / Mn) by GPC. When the content of the low-molecular-weight component is small, no adhered foreign matter is generated on the molding hot plate during molding, and equipment contamination can be prevented. For linear low density polyethylene (LLDPE), the molecular weight distribution (Mw / Mn) by GPC is preferably 7.0 or less, more preferably 4.5 or less. Moreover, the number average molecular weight Mn is preferably 20,000 or more, more preferably 23,000 or more.
The linear low-density polyethylene (LLDPE) may have one melting point peak or two or more melting point peaks measured by DSC, and the highest melting point peak temperature is 120 ° C. or higher. preferable. More preferably, a resin having the highest melting point peak temperature of 120 ° C. or higher and the lowest melting point peak not present at 100 ° C. or lower is preferable. More preferably, a resin having a highest melting point peak temperature of 120 ° C. or higher and a lowest melting point peak not present at 110 ° C. or lower is preferable. According to the above, the resin is not melted by heating at the time of molding, and equipment contamination can be prevented.

シー The sealant layer 2 may further contain low-density polyethylene.

When the sealant layer 2 further contains low-density polyethylene, the mass ratio of the linear low-density polyethylene to the low-density polyethylene in the resin constituting the sealant layer 2 is preferably in the range of 50:50 to 99: 1, The range is more preferably from 60:40 to 99: 1, and even more preferably from 80:20 to 99: 1.

The content of the linear low-density polyethylene in the entire resin constituting the sealant layer 2 is preferably 30 to 100% by mass, and more preferably 50 to 100% by mass. When the sealant layer 2 further contains low-density polyethylene, the total content of linear low-density polyethylene and low-density polyethylene is preferably 30 to 100% by mass, and 50 to 100% by mass. Is more preferred.
When the content of the linear low-density polyethylene is within the above preferred range, the heat seal strength is more stable, and when the sterilized paper is peeled off, paper residue on the sealant layer 2 is further suppressed.

The sealant layer 2 may contain an additive from the viewpoint of improving the low-temperature heat sealability. Examples of the additive include a terpene resin (for example, “Hirodine series” manufactured by Yashara Chemical Co., Ltd.).

The thickness of the sealant layer 2 is preferably from 3 to 70 μm, more preferably from 5 to 45 μm. When the thickness is at least the lower limit of the preferred range, a higher seal strength is obtained when heat-sealing with sterilized paper, and when the thickness is at most the lower limit, the effect of easy-opening property is higher when opening. .

(Base material layer)
The base material layer (also referred to as a core layer) 3 is a resin layer provided to be adjacent to the above-described sealant layer 2 for the purpose of imparting flexibility to the multilayer film 1. The resin that can be used for the base material layer 3 is not particularly limited as long as it is a resin that can impart the above function, and examples thereof include a polyethylene-based resin.

Examples of the polyethylene-based resin include ethylene homopolymers such as low-density polyethylene (LDPE) resin, linear low-density polyethylene (LLDPE) resin, medium-density polyethylene (MDPE) resin, and high-density polyethylene (HDPE) resin; Ethylene-vinyl acetate copolymer (EVA) resin, ethylene-methyl methacrylate copolymer (EMMA) resin, ethylene-ethyl acrylate copolymer (EEA) resin, ethylene-methyl acrylate copolymer (EMA) resin, ethylene- Ethylene copolymers such as ethyl acrylate-maleic anhydride copolymer (E-EA-MAH) resin, ethylene-acrylic acid copolymer (EAA) resin, ethylene-methacrylic acid copolymer (EMAA) resin; ionomers (ION) ) Resin, etc., alone or two or more types The combined used in.
As the polyethylene resin, the above-mentioned LLDPE is preferable. By using LLDPE as the resin contained in the base material layer 3, more stable heat seal strength (a synergistic effect with the resin containing linear low-density polyethylene used in the sealant layer 2) can be obtained.

The base material layer 3 may be only one layer or, as shown in FIG. 2, may be two or more layers. For example, by forming the base layer 3 from a plurality of layers made of different materials, characteristics such as hardness of the base layer 3 can be adjusted. Examples of the two or more base material layers include a base material layer having two layers of LDPE and LLDPE.

The thickness of the base material layer 3 is preferably from 15 to 150 μm, more preferably from 30 to 100 μm. When the thickness is not less than the lower limit of the preferred range, the flexibility of the multilayer film 1 is improved, and when it is not more than the upper limit, more stable sealing strength can be obtained.

In the multilayer film 1 of the present embodiment, the thickness ratio between the sealant layer 2 and the base material layer 3 is preferably in the range of 1: 0.5 to 1:15, and is preferably in the range of 1: 0.5 to 1:15. It is more preferably in the range of 1:10, more preferably in the range of 1: 2 to 1:10. When the above-mentioned ratio is at least the lower limit of the preferable range, an effect of preventing curling of the package is obtained, and when it is at most the upper limit, more stable sealing strength is obtained.

多層 The multilayer film 1 of the present embodiment may include another resin layer other than the sealant layer 2 and the base material layer 3 as long as the effects of the present invention are not impaired. In the multilayer film 1 shown in FIG. 2, an adhesive resin layer 4 and a pinhole-resistant layer 5 are laminated on the base layer 3 as other resin layers.

(Adhesive resin layer)
The adhesive resin layer 4 is a resin layer provided to increase the interlayer strength of each resin layer constituting the multilayer film 1 other than the layer between the sealant layer 2 and the base material layer 3 described above.

As the adhesive resin applicable to the adhesive resin layer 4, a known adhesive olefin resin, for example, an adhesive polypropylene resin, an adhesive polyethylene resin, or the like is used. The adhesive resin layer 4 may contain an antioxidant to prevent its oxidation. As the antioxidant, a known antioxidant, for example, a hindered phenol-based antioxidant, a phosphorus-based antioxidant, a thioether-based antioxidant, or the like is used alone or in combination of two or more. Further, the adhesive resin layer 4 may contain cellulose nanofibers from the viewpoint of improving adhesiveness and mechanical properties.

厚み The thickness of the adhesive resin layer 4 is not particularly limited as long as each layer can be joined with a required adhesive strength, but is preferably 2 to 30 μm, more preferably 5 to 25 μm.

(Pinhole resistant layer)
The pinhole-resistant layer 5 is a resin layer provided for imparting pinhole resistance to the multilayer film 1. The pinhole-resistant layer 5 preferably contains a polyamide resin from the viewpoint of improving the pinhole resistance. Examples of the polyamide resin contained in the anti-pinhole layer 5 include 4-nylon, 6-nylon, 7-nylon, 11-nylon, 12-nylon, 46-nylon, 66-nylon, 69-nylon, and 610-nylon Nylon, 611-nylon, 612-nylon, 6T-nylon, 6I nylon, 6-nylon and 66-nylon copolymer (nylon 6/66), 6-nylon and 610-nylon copolymer, 6-nylon and 611-nylon Copolymer, copolymer of 6-nylon and 12-nylon (nylon 6/12), copolymer of 6-nylon and 612 nylon, copolymer of 6-nylon and 6T-nylon, copolymer of 6-nylon and 6I-nylon, 6-nylon And copolymers of 66-nylon and 610-nylon, 6- Copolymer of nylon and 66-nylon and 12-nylon (nylon 6/66/12), copolymer of 6-nylon and 66-nylon and 612-nylon, copolymer of 66-nylon and 6T-nylon, 66-nylon and 6I- Nylon copolymer, 6T-nylon and 6I-nylon copolymer, 66-nylon and 6T-nylon and 6I-nylon copolymer, amorphous nylon and the like. Among these, 6-nylon, 12-nylon, 66-nylon, nylon 6/66, nylon 6/12, nylon 6/66/12, and the like are preferable from the viewpoint of heat resistance, mechanical strength, and availability. , 6-nylon are more preferred.

総 The total thickness of the pinhole-resistant layer 5 is not particularly limited, but is preferably 10 to 90 μm, and more preferably 12 to 50 μm.

(Additive)
The multilayer film 1 of the present embodiment may contain a known lubricant or additive in the above-described sealant layer 2 and base material layer 3 for the purpose of preventing slippage and blocking and imparting anti-fogging property as needed. You may give. For the purpose of slipperiness and blocking prevention, organic lubricants such as oleic amide and erucamide, and inorganic lubricants such as silica, zeolite and calcium carbonate can be exemplified. In order to impart antifogging property, a known surfactant or the like can be appropriately used.

<Method for producing multilayer film>
Next, an example of a method for manufacturing the above-described multilayer film 1 will be described.
The method for producing the above-mentioned multilayer film 1 is not particularly limited, but a co-extrusion T-die method such as a feed block method or a multi-manifold method in which a resin or the like as a raw material is melt-extruded by several extruders, An air-cooled or water-cooled co-extrusion inflation method and a laminating method are mentioned. Among them, a method of forming a film by a co-extrusion T-die method is particularly preferable because it is excellent in controlling the thickness of each layer.

Examples of the laminating method include a dry laminating method, a laminating method, a hot laminating method, a wet laminating method, and a thermal (thermal) laminating method in which a single-layer sheet or film forming each layer is bonded using an appropriate adhesive. And their methods can be used in combination. Moreover, you may laminate | stack by the method by coating.

<Package>
Next, an example of a package using the above-described multilayer film 1 will be described.
The package of the present embodiment includes the above-described multilayer film and sterile paper, and at least a part of the sealant layer of the multilayer film is heat-sealed to the surface of the sterile paper.

The sterilizing paper applicable to the package of the present embodiment is heat-sealable with a sealant layer, has air permeability, prevents bacteria from passing therethrough (has a fungicidal property), and is sterilized. The sheet is not particularly limited as long as it can be processed and is a sheet mainly composed of paper. Examples of the sterilized paper include Medica D (manufactured by Oji F-Tex).

When the package of the present embodiment is used as a medical package, it is preferable that the sterilized paper has small holes that are capable of exhibiting air permeability and bacterial barrier properties. Specifically, it is preferably made of sterilized paper having a fiber weight in the range of 0.0001 to 20 dtex and a basis weight of 10 to 300 g / m ² .

包装 The package of the present embodiment can be used as a deep-drawn package by deep-drawing the bottom material, filling it with contents such as gauze, covering it with a lid, and heat-sealing. In particular, when the above-described multilayer film is used as the bottom material of the deep-drawn package and sterilized paper is used as the lid, a good deep-drawn package can be obtained.

The package of the present embodiment can be manufactured by bonding a multilayer film used as a bottom material and sterilized paper used as a lid material by bonding means such as heat sealing. Specifically, a package can be produced by heat-sealing the multilayer film and sterilized paper, preferably in a temperature range of 135 to 155 ° C.
Further, in the package of the present embodiment, the sealing strength between the multilayer film 1 and the sterilized paper is preferably 1.0 to 7.7 N / 15 mm, and is 1.2 to 6.0 N / 15 mm. Is more preferable. When the above-mentioned seal strength is not less than the lower limit of the above-mentioned preferred range, the sealing property of the package is higher, and if it is not more than the upper limit, better openability (such as tearing of fibers and fluffing during peeling). Suppression) is obtained.

As described above, according to the multilayer film of the present embodiment, the sealant layer provided to be the surface layer contains at least linear low-density polyethylene, and the density of the linear low-density polyethylene. Is 0.93 or more, the package obtained by heat-sealing the multilayer film and the sterilized paper has an appropriate sealing strength, and when the sterilized paper is peeled off, paper residue remains on the peeling surface of the bottom material. It has an excellent effect that generation can be suppressed and a package having no hygiene problem can be provided.

The package of the present embodiment is configured to include the multilayer film 1 and sterilized paper, and the sealing strength between the multilayer film 1 and the sterilized paper is 1.0 to 7.7 (N / 15 mm). Are more excellent in terms of seal strength and easy peelability.

Although the embodiment of the present invention has been described in detail with reference to the drawings, the specific configuration is not limited to this embodiment, and includes a design and the like without departing from the gist of the present invention. For example, the multilayer film 1 shown in FIG. 1 has a configuration in which the sealant layer 2 and the base material layer 3 are laminated in this order, but this is an example, and the present invention is not limited to this. For example, as shown in FIG. 2, the multilayer film according to one embodiment of the present invention includes a sealant layer 2, a base layer 30, a base layer 31, an adhesive resin layer 4, and a pinhole-resistant layer 5 laminated in this order. The adhesive resin layer 4 and the pinhole-resistant layer 5 may be alternately laminated two by two, or three or more layers may be alternately laminated. It may be.

In the multilayer film 1, a layer having another function may be newly provided between each layer or on the outermost layer opposite to the sealant layer 2. For example, from the viewpoint of providing the multilayer film 1 with an oxygen gas barrier property, a resin layer made of an ethylene-vinyl alcohol copolymer resin may be provided. Further, from the viewpoint of imparting strength to the multilayer film 1, a resin layer made of a polypropylene-based resin (PP) may be provided. From the viewpoint of imparting flexibility to the multilayer film 1, a resin layer composed of an ethylene-vinyl acetate copolymer layer (EVA layer) or a polyethylene layer (PE layer) may be provided.

Hereinafter, the present invention will be described in more detail based on Examples and Comparative Examples, but the present invention is not limited thereto.

<Preparation of multilayer film>
(Example 1)
A multilayer film having the configuration shown in FIG. 1 and further including the adhesive resin layer and the pinhole-resistant layer in the lamination order shown in FIG. 2 was produced by the following procedure.
First, nylon (manufactured by Ube Industries, product number: 1022B) was prepared as a resin contained in the pinhole-resistant layer.
Further, as a resin contained in the adhesive resin layer (hereinafter, simply referred to as “adhesive layer”), an adhesive polyethylene resin (manufactured by Mitsui Chemicals, Inc., product number: NF536) was prepared.
Further, polyethylene (manufactured by Ube Maruzen Polyethylene Corporation, product number: F222NH) was prepared as a resin contained in the base material layer.
Further, as a resin contained in the sealant layer, a metallocene-catalyzed linear low-density polyethylene (mLLDPE) resin (manufactured by Ube Maruzen Polyethylene Co., Ltd., product number: 4040FC, melting point 126 ° C.) and a low-density polyethylene (LDPE) (Ube Maruzen Polyethylene Co., Ltd.) (Product number: F222NH, melting point: 110 ° C.), and these were mixed (kneaded) in a ratio of 80:20. The density of the resin contained in the resulting sealant layer (g / cm ³⁾ was 0.938 g / cm ^3.
Next, a multilayer film having a four-layer structure in the order of sealant layer / base layer / adhesive resin layer / pinhole-resistant layer was produced (laminated) by extrusion.
The thickness of the sealant layer was 12 μm, the thickness of the base material layer was 68 μm, the thickness of the adhesive resin layer was 14 μm, and the thickness of the pinhole-resistant layer was 16 μm.
In addition, the density of the resin contained in the sealant layer was measured using a specific gravity measuring device (Shibayama Scientific Instruments) based on the density gradient tube method of JIS K7112.
The melting point was measured by differential scanning calorimetry (DSC, DSC6200, manufactured by Hitachi High-Tech Science Corporation) in a nitrogen atmosphere from 25 ° C to 300 ° C, at a rate of 5 ° C / min, and then to 25 ° C. It was cooled at a rate of −50 ° C./min, heated again from 25 ° C. to 300 ° C. at a rate of 5 ° C./min, and measured at the time of re-heating to obtain a temperature.

(Example 2)
As the resin contained in the sealant layer, instead of the metallocene-catalyzed linear low-density polyethylene (mLLDPE) resin (manufactured by Ube Maruzen Polyethylene Co., Ltd., product number: 4040FC), a metallocene-catalyzed linear low-density polyethylene (mLLDPE) resin (Sumitomo Chemical) The product is manufactured in the same manner as in Example 1 except that a multi-layer film of sealant layer / base material layer / adhesive resin layer / pinhole-resistant layer is used in the same manner as in Example 1, except that FV407 (product number: FV407, melting point: 124 ° C.) is used. Was produced (laminated) by extrusion. The density of the resin contained in the resulting sealant layer (g / cm ³⁾ was 0.930 g / cm ^3.
The thickness of the sealant layer was 14 μm, the thickness of the base material layer was 68 μm, the thickness of the adhesive resin layer was 14 μm, and the thickness of the pinhole-resistant layer was 16 μm.

(Example 3)
As the resin contained in the sealant layer, instead of the metallocene-catalyzed linear low-density polyethylene (mLLDPE) resin (manufactured by Ube Maruzen Polyethylene Co., part number: 4040FC), a metallocene-catalyzed linear low-density polyethylene (mLLDPE) resin (prime polymer) (Product number: SP3530, melting point: 97, 121, 125 ° C.), except that sealant layer / base material layer / adhesive resin layer / pinhole-resistant layer were used in the same manner as in Example 1. A multilayer film having the configuration was produced (laminated) by extrusion. The density of the resin contained in the resulting sealant layer (g / cm ³⁾ was 0.931 g / cm ^3.
The thickness of the sealant layer was 14 μm, the thickness of the base material layer was 68 μm, the thickness of the adhesive resin layer was 14 μm, and the thickness of the pinhole-resistant layer was 16 μm.

(Example 4)
As the resin contained in the sealant layer, low-density polyethylene (LDPE) was not used, and a metallocene-catalyzed linear low-density polyethylene (mLLDPE) resin (manufactured by Ube Maruzen Polyethylene Co., Ltd., product number: 4040FC, melting point 126 ° C., density 0.938 g) / Cm ³ ), except that only a sealant layer / substrate layer / adhesive resin layer / pinhole-resistant layer was formed in the same manner as in Example 1 except that only a multilayer film was extruded. (Laminated). The density of the resin contained in the resulting sealant layer (g / cm ³⁾ was 0.938 g / cm ^3.
The thickness of the sealant layer was 12 μm, the thickness of the base material layer was 68 μm, the thickness of the adhesive resin layer was 14 μm, and the thickness of the pinhole-resistant layer was 16 μm.

(Comparative Example 1)
As the resin contained in the sealant layer, a metallocene-catalyzed linear low-density polyethylene (mLLDPE) resin (manufactured by Ube Maruzen Polyethylene Co., part number: 4040FC) is used instead of a metallocene-catalyzed linear low-density polyethylene (mLLDPE) resin (DLD. (Manufactured by Chemical Co., Ltd., product number: 5220G, melting point: 102, 113, 124 ° C.) except that sealant layer / base layer / adhesive resin layer / pinhole-resistant layer was used in the same manner as in Example 1. A multilayer film having a layer configuration was produced (laminated) by extrusion. The density (g / cm ³ ) of the resin contained in the obtained sealant layer was 0.915 g / cm ³ .
The thickness of the sealant layer was 14 μm, the thickness of the base material layer was 68 μm, the thickness of the adhesive resin layer was 14 μm, and the thickness of the pinhole-resistant layer was 16 μm.

(Comparative Example 2)
As the resin contained in the sealant layer, instead of the metallocene-catalyzed linear low-density polyethylene (mLLDPE) resin (manufactured by Ube Maruzen Polyethylene Co., part number: 4040FC), a linear low-density polyethylene (LLDPE) resin (manufactured by Prime Polymer Co., Ltd.) Extruding a sealant layer / base material layer / adhesive resin layer / pinhole-resistant layer in the same manner as in Example 1 except that a multi-layered film was extruded. Fabricated (laminated) by processing. The density of the resin contained in the resulting sealant layer (g / cm ³⁾ was 0.923 g / cm ^3.
The thickness of the sealant layer was 14 μm, the thickness of the base material layer was 68 μm, the thickness of the adhesive resin layer was 14 μm, and the thickness of the pinhole-resistant layer was 16 μm.

(Comparative Example 3)
As the resin contained in the sealant layer, instead of the metallocene-catalyzed linear low-density polyethylene (mLLDPE) resin (manufactured by Ube Maruzen Polyethylene, part number: 4040FC), the metallocene-catalyzed linear low-density polyethylene resin (manufactured by Ube Maruzen Polyethylene) Extruding a sealant layer / substrate layer / adhesive resin layer / pinhole-resistant layer in the same manner as in Example 1 except for using the following: Fabricated (laminated) by processing. The density of the resin contained in the resulting sealant layer (g / cm ³⁾ was 0.913 g / cm ^3.
The thickness of the sealant layer was 14 μm, the thickness of the base material layer was 68 μm, the thickness of the adhesive resin layer was 14 μm, and the thickness of the pinhole-resistant layer was 16 μm.

<Manufacture of packaging>
The multilayer films obtained in Examples and Comparative Examples and sterilized paper were stacked such that the sterilized paper side was on the hot plate side, and a Teflon (registered trademark) sheet was placed thereon. A sample for evaluation of the package was produced by sealing under the conditions. Peeling was performed in the MD and TD directions of the film.
・ Seal pressure: 2.0 kgf / cm ² (0.2 MPa)
-Sealing time: 3.0 seconds-Sealing temperature: 130 ° C, 140 ° C, 150 ° C (3 conditions at 10 ° C intervals)

<Evaluation>
About the evaluation sample of the package obtained by the Example and the comparative example, heat sealing property (seal strength), evaluation of the paper residue of a peeling surface, evaluation of low molecular weight volatile components, evaluation of equipment contamination, evaluation of molecular weight distribution, and The hot plate adhesion was evaluated.

(Evaluation of heat sealability)
The heat sealability was evaluated by measuring the seal strength at a seal width of 15 mm using a tensile tester (TENSILON RTG-1310, manufactured by A & D Corporation). The peeling speed was 200 mm / min. Table 1 shows the seal strengths of the evaluation samples prepared at the respective seal temperatures for the examples and the comparative examples.

(Evaluation of paper residue on peeled surface)
The evaluation of the remaining paper was performed by peeling off the lid material and the bottom material of the package used as the evaluation sample using the five evaluation samples described above.
In the evaluation, the peeled surfaces of the lid material and the bottom material after peeling were observed, and the presence or absence of paper residue on the peeled surface of the bottom material was determined. Table 1 shows the number of samples having paper residue in the evaluation samples prepared at each sealing temperature for the examples and the comparative examples.

(Evaluation of low molecular weight volatile components)
The evaluation of the low molecular weight volatile component is performed by pyrolysis-GC-MS (pyrolyzer: Frontier Laboratories, PY-2020iD type heating furnace type pyrolyzer, GC: Agilent Technologies, 6890N type gas chromatograph, MS: Agilent) Using a 5975B type mass detector (manufactured by Technology Co., Ltd.), about 27 mg of a linear low-density polyethylene sample contained in the sealant layer was heated under a heating atmosphere of helium at 120 ° C. for 10 minutes. Regarding the quantification of the detection component, GC-MS measurement was performed using an acetone-diluted solution of n-decane having a known concentration, the peak area values of the generated gas components were compared, and the converted quantification values for the standard sample were summed up. It was calculated as a weight fraction relative to the sample weight. Table 2 shows the weight fraction with respect to the sample weight of each linear low-density polyethylene in Examples and Comparative Examples.

(Evaluation of equipment contamination)
For the evaluation of equipment contamination, the multilayer films obtained in Examples and Comparative Examples were cut into 10 cm squares, layered on aluminum foil, pressed using a press machine under the following conditions, and observed for low molecular weight components transferred to aluminum foil. It was done by doing.
・ Pressing pressure: 10MPa
・ Press time: 10 minutes ・ Press temperature: 110 ° C
The evaluation criteria are shown below.
A: The transition area of the low molecular weight component to the aluminum foil is 5% or less of the whole aluminum foil. B: The transition area of the low molecular weight component to the aluminum foil is more than 5% of the total cure of the aluminum foil. The evaluation results are shown for the multilayer films obtained in Comparative Examples. In the table, "-" indicates that the evaluation has not been performed.

(Evaluation of molecular weight distribution)
The molecular weight distribution (Mw / Mn) of the linear low-density polyethylenes of Examples and Comparative Examples was measured using a GPC apparatus (Apparatus: PL-GPC220 manufactured by Agilent, column: Agilent PLgel Olexis x 2 + Guard). After the linear low-density polyethylene of the example was eluted with orthodichlorobenzene, it was injected into a column at a temperature of 145 ° C, a concentration of 0.1 wt / vol%, and a flow rate of 1.0 ml / min, and the amount of elution was detected by a differential refractometer. Was determined from the obtained elution curve. Table 3 shows the molecular weight distribution (Mw / Mn) and the number average molecular weight (Mn) of the linear low-density polyethylenes of Examples and Comparative Examples. In the table, "-" indicates that the evaluation has not been performed.

(Evaluation of hot plate adhesion)
Evaluation of hot plate adhesion was performed using a GEA PowerPak ST 420, after cleaning the hot plate with alcohol, operating at a molding temperature of 108 ° C., a heating time of 9.9 seconds, and without sealing for 7 hours. Was rubbed with a spatula to confirm the presence or absence of deposits. Table 3 shows the presence or absence of hot plate deposits for the examples and comparative examples.

As shown in Table 1, in Examples 1 to 4, in all the evaluation samples at the sealing temperatures of 140 ° C. and 150 ° C., the sealing strength was 1.2 N / 15 mm or more, and the heat was applied in the temperature range of 140 ° C. and 150 ° C. It was confirmed that it was sealable and had excellent heat sealability. In addition, in all of the evaluation samples at the sealing temperatures of 130 ° C. and 140 ° C., there is no paper residue on the peeling surface when peeling, and even at the sealing temperature of 150 ° C., the paper residue on the peeling surface is small and the paper residue on the peeling surface is suppressed. It was confirmed that.
On the other hand, when the sealing temperature was 140 ° C. and 150 ° C., the sealing strength was higher than when the sealing temperature was 130 ° C. As described above, the case where the sealing temperature is 140 ° C. and 150 ° C. is particularly excellent in both the high sealing strength and the effect of suppressing the residual paper on the peeled surface.

In contrast, in Comparative Examples 1 to 3, in any of the evaluation samples having a sealing temperature of 130 ° C. or higher, a remarkable paper residue on the peeled surface occurred. In particular, in Comparative Example 3, in all the evaluation samples having a sealing temperature of 130 ° C. or higher, a remarkable paper residue occurred on the peeled surface.

Table 2 shows the results of pyrolysis-GC-MS for Examples 1, 3 and 4. From these results, it can be seen that Examples 1 and 4 have a smaller amount of low molecular weight volatile components by GC-MS as compared with Example 3, so that less gas is generated during molding and equipment contamination can be further prevented. Inferred.

Table 2 shows the evaluation of equipment contamination with a press machine for Examples 1 to 3 and Comparative Examples 1 to 3. From these results, it can be seen that in Example 3 in which the amount of low-molecular-weight volatile components in GC-MS is larger than that in Example 1, the migration of low-molecular-weight volatile components is larger and the equipment is more easily contaminated.

Table 2 shows melting points (melting point peak temperatures) of Examples 1 to 4 and Comparative Examples 1 to 3 based on DSC measurement results. From these results, Examples 1, 2 and 4 have the highest melting point peak temperature of 120 ° C. or higher and the lowest melting point peak does not exist at 100 ° C. or lower as compared with Example 3, thereby further preventing equipment contamination. It is speculated that it can be done.

Further, from the results of the molecular weight distribution (Mw / Mn) by GPC shown in Table 3, Examples 1 and 4 have narrower molecular weight distributions and smaller amounts of low molecular weight components than those of Example 3, and It is considered that there is no generation of extraneous matter even when the operation time of the equipment is long because the amount of extraneous matter attached to the hot plate is small and the production equipment can be prevented from being contaminated.

多層 The multilayer film and the package of the present invention can be used as a package for medical devices such as gauze and catheter and medical devices.

DESCRIPTION OF SYMBOLS 1 ... Multilayer film 2 ... Sealant layer 3 ... Base layer 30 ... Base layer 1
31 ... base material layer 2
4 ... adhesive resin layer 5 ... pinhole resistant layer

Claims

At least a sealant layer provided to be a surface layer,
A multilayer film, wherein the sealant layer contains at least linear low-density polyethylene, and the linear low-density polyethylene has a density of 0.93 or more.
The multilayer according to claim 1, wherein the sealant layer further comprises a low-density polyethylene, and a mass ratio of the linear low-density polyethylene to the low-density polyethylene ranges from 50:50 to 99: 1. the film.
The multilayer film according to claim 1 or 2, further comprising a base layer provided adjacent to the sealant layer and including a polyethylene-based resin.
The multilayer film according to claim 3, wherein the base material layer includes a linear low-density polyethylene.
The multilayer film according to claim 3, wherein the ratio of the thickness of the sealant layer to the thickness of the base material layer is in the range of 1: 0.5 to 1:15.
The multilayer film according to any one of claims 1 to 5, wherein the low-molecular-weight volatile component of the linear low-density polyethylene contained in the sealant layer is 0.1 wt% or less.
The molecular weight distribution (Mw / Mn) of the linear low density polyethylene contained in the sealant layer is 7.0 or less, and the number average molecular weight Mn of the linear low density polyethylene is 20,000 or more. The multilayer film according to any one of claims 1 to 6.
The multilayer film according to any one of claims 1 to 7, which can be heat-sealed with sterilized paper at a temperature in the range of 135 to 155 ° C.
A multilayer film according to any one of claims 1 to 8, and a sterilized paper,
A package wherein at least a part of the sealant layer of the multilayer film is heat-sealed to the surface of the sterilized paper.
(10) The package according to (9), wherein the sealing strength between the multilayer film and the sterilized paper is 1.0 to 7.7 (N / 15 mm).