CN111163935B

CN111163935B - Packaging body

Info

Publication number: CN111163935B
Application number: CN201880064245.7A
Authority: CN
Inventors: 佐佐木研太
Original assignee: Sumitomo Bakelite Co Ltd
Current assignee: Sumitomo Bakelite Co Ltd
Priority date: 2017-10-03
Filing date: 2018-09-26
Publication date: 2022-08-16
Anticipated expiration: 2038-09-26
Also published as: WO2019069759A1; CN111163935A; JP2020078942A; JP7060029B2; JPWO2019069759A1

Abstract

A multilayer film including at least a sealant layer provided so as to become a surface layer, and a package body, wherein the sealant layer (2) contains at least a first resin having a melting point of 80 to 110° C. and The second resin having a melting point of 130 to 200° C., the package body includes the multilayer film and a polyethylene nonwoven fabric, and at least a part of the sealant layer of the multilayer film is heat-sealed on the nonwoven fabric. on the woven surface.

Description

Packaging body

Technical Field

The present invention relates to a multilayer film and a package.

The present application claims priority based on japanese patent application No. 2017-193593, filed on japanese application at 10/3/2017, and the contents thereof are incorporated herein by reference.

Background

In recent years, a package formed by deep drawing (hereinafter, also referred to as a "deep drawn package") has been used as a medical package. The deep-drawn package is obtained by joining a base material comprising a multilayer film having a recess formed in the central portion thereof to a lid material comprising polyethylene nonwoven fabric, sterilized paper or the like (hereinafter, also referred to as "PE nonwoven fabric or the like") by heat sealing or the like. The concave portion accommodates a gauze for business use, a cotton swab, a medical instrument, and the like.

Conventionally, as a substrate for a medical package, a multilayer film obtained by laminating a polyester film or a nylon film with a heat-sealable resin film (lamination method) has been widely used. On the other hand, as the lid material, from the viewpoint of the permeability of the sterilizing gas in the sterilization step, as described above, a polyethylene nonwoven fabric or sterilized paper is used.

However, the medical package is required to have easy opening properties depending on the use method thereof. In addition, as a lid material for the medical packaging body, a polyethylene nonwoven fabric is selected from the viewpoint of importance on hygiene. Since polyethylene nonwoven fabrics coated with an adhesive and provided with easy-opening properties are expensive and have reduced air permeability, easy-peeling properties are provided on the multilayer film side sealed with polyethylene nonwoven fabrics. In order to impart easy-opening properties to a medical package, a multilayer film used as a substrate is known in which a resin layer (hereinafter, also referred to as an "easy-peeling layer") having easy-peeling properties is provided on the sealing side with a nonwoven fabric made of PE or the like (patent document 1). Also known is a coextruded multilayer film for deep drawing, which comprises a polyamide resin, a sealing layer heat-sealable with a polyethylene nonwoven fabric or sterilized paper at 135 ℃ or lower, and an easily peelable layer having interlayer releasability from the sealing layer (patent document 2).

Documents of the prior art

Patent document

Patent document 1 Japanese patent laid-open No. 2014-162162

Patent document 2, japanese patent application laid-open No. 2014-19006.

Disclosure of Invention

Problems to be solved by the invention

However, it is actually required that a multilayer film used for a medical package or the like can be heat-sealed to a polyethylene nonwoven fabric in a wider temperature range.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a multilayer film and a package which can be heat-sealed with a polyethylene nonwoven fabric in a wide temperature range of 135 ℃ or less and which have excellent releasability.

Means for solving the technical problems

In order to achieve the above object, the present invention adopts the following configuration.

[1] A multilayer film comprising at least a sealant layer provided to serve as a surface layer,

the sealant layer contains a first resin having a melting point of 80 to 110 ℃ and a second resin having a melting point of 130 to 200 ℃.

[2] The multilayer film according to [1], wherein the first resin contains a polyethylene resin.

[3] The multilayer film according to [2], wherein the polyethylene resin contains at least one selected from homopolymers and copolymers of ethylene.

[4] The multilayer film according to any one of [1] to [3], wherein the second resin contains polypropylene.

[5] The multilayer film according to [3] or [4], wherein the ethylene copolymer contains an ethylene-vinyl acetate copolymer.

[6] The multilayer film according to [4] or [5], wherein the polypropylene contains homopolypropylene.

[7] The multilayer film according to any one of [1] to [6], wherein the sealant layer contains 50 to 99 mass% of the first resin and 1 to 50 mass% of the second resin.

[8] The multilayer film according to any one of [1] to [7], which is provided with: and a base material layer which is provided adjacent to the sealant layer and contains a polyethylene resin.

[9] The multilayer film according to [8], wherein the substrate layer contains a high-density polyethylene resin.

[10] The multilayer film according to [8] or [9], wherein a ratio of thicknesses of the sealant layer and the base material layer is in a range of 1:0.5 to 1: 10.

[11] The multilayer film according to any one of [1] to [10], wherein the multilayer film can be heat-sealed with a polyethylene nonwoven fabric at 105 to 135 ℃.

[12] A package comprising the multilayer film according to any one of [1] to [11] and a polyethylene nonwoven fabric, wherein at least a part of a sealant layer of the multilayer film is heat-sealed to a surface of the nonwoven fabric.

[13] The package according to [12], wherein the peel strength between the multilayer film and the nonwoven fabric is 120 to 770(g/25 mm).

ADVANTAGEOUS EFFECTS OF INVENTION

As described above, the multilayer film of the present invention is configured such that the sealant layer provided to serve as the surface layer contains the first resin having a melting point of 80 to 110 ℃ and the second resin having a melting point of 130 to 200 ℃, and therefore can be heat-sealed with the polyethylene nonwoven fabric in a wide temperature range of 135 ℃ or less, and has good releasability.

The package of the present invention is configured to include the multilayer film of the present invention, and therefore has desired easy peelability to a polyethylene nonwoven fabric.

Drawings

Fig. 1 is a schematic cross-sectional view of a multilayer film 1 to which an embodiment of the present invention is applied.

Fig. 2 is a schematic cross-sectional view of a multilayer film 1 to which an embodiment of the present invention is applied.

Detailed Description

Hereinafter, a multilayer film and a package to which an embodiment of the present invention is applied will be described in detail. In the drawings used in the following description, for the sake of easy understanding of the features of the present invention, the features may be shown in an enlarged scale, and the dimensional ratios of the components are not necessarily the same as the actual ones.

< multilayer film >

First, the structure of a multilayer film to which an embodiment of the present invention is applied will be described. Fig. 2 is a schematic cross-sectional view of a multilayer film 1 to which an embodiment of the present invention is applied. As shown in fig. 1, the multilayer film 1 of the present embodiment has a schematic structure including a sealant layer 2 provided as a surface layer and a base material layer 3 provided adjacent to the sealant layer 2. As shown in fig. 2, the multilayer film 1 of the present embodiment may have a schematic structure including a sealant layer 2 provided as a surface layer, a base layer 3 provided adjacent to the sealant layer 2, and another resin layer laminated on the base layer 3. The multilayer film 1 of the present embodiment can be used as a package, and particularly can be used as a film for a base material of a medical package.

(sealant layer)

The sealant layer 2 is a resin layer provided for bonding to a nonwoven fabric or the like to be bonded by heat sealing and for providing easy-opening property. The sealant layer 2 contains a first resin having a melting point of 80 to 110 ℃, preferably 85 to 105 ℃, more preferably 85 to 100 ℃, and a second resin having a melting point of 130 to 200 ℃, preferably 140 to 170 ℃, more preferably 150 to 165 ℃. When the melting point of the first resin is not less than the lower limit of the above range, the first resin is not sticky even in a high temperature environment such as summer and can be heat-sealed with a polyethylene nonwoven fabric with an appropriate peel strength within a range of 105 to 135 ℃. On the other hand, if the upper limit value of the above range is not more than the upper limit value, the polyethylene nonwoven fabric can be sealed without melting at the time of heat sealing.

When the melting point of the second resin is equal to or higher than the lower limit of the above range, softening of the second resin is suppressed during sealing and the peel strength is stabilized, and when the melting point is equal to or lower than the upper limit of the above range, for example, fiber tearing of the polyethylene nonwoven fabric can be suppressed during peeling after joining with the polyethylene nonwoven fabric.

The first resin that can be used for the sealant layer 2 is not particularly limited as long as it has the above melting point, and examples thereof include polyethylene resins.

As the polyethylene resin, for example, homopolymers of ethylene 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 copolymers such as 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-ethyl acrylate-maleic anhydride copolymer (E-EA-MAH) resin, ethylene-acrylic ester copolymer (EAA) resin, and ethylene-methacrylic acid copolymer (EMAA) resin; ionomer (ION) resins, and the like.

The polyethylene resin preferably contains a homopolymer or a copolymer of ethylene, and may contain both of them. The polyethylene resin is more preferably a homopolymer or a copolymer of ethylene, and may be both of them.

The ethylene copolymer preferably contains an ethylene-vinyl acetate copolymer or an ethylene-acrylic ester copolymer, more preferably contains an ethylene-vinyl acetate copolymer, and still more preferably contains an ethylene-vinyl acetate copolymer.

The second resin that can be used for the sealant layer 2 is not particularly limited as long as it has the above melting point, and examples thereof include resins of polypropylene (PP) and Polybutylene (PB).

The polypropylene may be a homopolymer, a random copolymer, a block copolymer or the like, or a mixture of two or more thereof, and among them, a homopolypropylene polymer is preferably used.

The content of the first resin constituting the sealant layer 2 is preferably 50 to 99 mass%, more preferably 65 to 95 mass%, and still more preferably 75 to 95 mass%.

The content of the first resin constituting the sealant layer 2 is a content of the first resin component with respect to a total mass (100 mass%) of all components constituting the sealant layer 2.

The content of the second resin constituting the sealant layer 2 is preferably 1 to 50 mass%, more preferably 5 to 35 mass%, and still more preferably 5 to 25 mass%.

The content of the second resin constituting the sealant layer 2 is a content of the second resin component with respect to a total mass (100 mass%) of all components constituting the sealant layer 2.

The sealant layer 2 may contain an additive from the viewpoint of improving the low-temperature heat sealability. Examples of the additive include terpene resins (YASUHARA CHEMICAL co., ltd., HIRODINE series) and the like.

The thickness of the sealant layer 2 is preferably 3 to 70 μm, and more preferably 5 to 45 μm. When the thickness is equal to or more than the lower limit of the preferable range, a predetermined peel strength can be obtained when heat-sealing with the polyethylene nonwoven fabric, and when the thickness is equal to or less than the upper limit, an effect of easy opening can be obtained when opening the package.

(substrate layer)

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

As the polyethylene resin, the above MDPE or HDPE is preferable, and HDPE is more preferable. By using the base layer 3 containing HDPE, stable hot peel strength can be obtained.

As shown in fig. 2, the base material layer 3 may be only 1 layer or may be a multilayer of two or more layers. For example, by forming the base material layer 3 of a plurality of layers of different materials, the properties such as the hardness of the base material layer 3 can be adjusted. Examples of the two or more substrate layers include a substrate layer having two layers of the HDPE and LLDPE.

The thickness of the base material layer 3 is preferably 15 to 150 μm, and more preferably 30 to 100 μm. When the thickness is not less than the lower limit of the preferable range, flexibility can be obtained, and when the thickness is not more than the upper limit, stable peel strength can be obtained.

In the multilayer film 1 of the present embodiment, the thickness ratio of the sealant layer 2 to the base material layer 3 is preferably in the range of 1:0.5 to 1:10, more preferably in the range of 1:0.5 to 1:7, and still more preferably in the range of 1:1 to 1: 5. When the ratio is equal to or higher than the lower limit of the preferable range, the effect of preventing curling of the package can be obtained, and when the ratio is equal to or lower than the upper limit, stable peel strength can be obtained.

The multilayer film 1 of the present embodiment may further include another resin layer in addition to the sealant layer 2 and the base layer 3, within a range not to impair the effects of the present invention. In the multilayer film 1 shown in fig. 2, an adhesive resin layer 4 and a pinhole-resistant layer 5 are laminated as other resin layers on a base material layer 3.

(adhesive resin layer)

The adhesive resin layer 4 is a resin layer provided to improve interlayer strength of each resin layer constituting the multilayer film 1, in addition to the interlayer between the sealant layer 2 and the base material layer 3.

As the adhesive resin that can be applied to the adhesive resin layer 4, known adhesive olefin resins, for example, adhesive polypropylene resins, adhesive polyethylene resins, and the like are used. To prevent oxidation, an antioxidant may be included. As the antioxidant, a known antioxidant, for example, a hindered phenol-based antioxidant, a phosphorus-based antioxidant, a thioether-based antioxidant, or the like can be used singly or in combination of two or more kinds. In addition, cellulose nanofibers may be contained from the viewpoint of improving adhesiveness and mechanical properties.

The thickness of the adhesive resin layer 4 is not particularly limited as long as the layers can be bonded with a desired adhesive strength, but is preferably 2 to 30 μm, and 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 pinhole resistance. Examples of the polyamide resin contained in the pinhole-resistant layer 5 include 4-nylon, 6-nylon, 7-nylon, 11-nylon, 12-nylon, 46-nylon, 66-nylon, 69-nylon, 610-nylon, 611-nylon, 612-nylon, 6T-nylon, 6I nylon, a copolymer of 6-nylon and 66-nylon (nylon 6/66), a copolymer of 6-nylon and 610-nylon, a copolymer of 6-nylon and 611-nylon, a copolymer of 6-nylon and 12-nylon (nylon 6/12), a copolymer of 6-nylon and 612 nylon, a copolymer of 6-nylon and 6T-nylon, a copolymer of 6-nylon and 6I-nylon, a copolymer of nylon, a copolymer, and a copolymer, A copolymer of 6-nylon and 66-nylon and 610-nylon, a copolymer of 6-nylon and 66-nylon and 12-nylon (nylon 6/66/12), a copolymer of 6-nylon and 66-nylon and 612-nylon, a copolymer of 66-nylon and 6T-nylon, a copolymer of 66-nylon and 6I-nylon, a copolymer of 6T-nylon and 6I-nylon, a copolymer of 66-nylon and 6T-nylon and 6I-nylon, amorphous nylon, and the like. Among them, 6-nylon, 12-nylon, 66-nylon, nylon 6/66, nylon 6/12, nylon 6/66/12 and the like are preferable, and 6-nylon is more preferable, from the viewpoint of heat resistance, mechanical strength and easiness of obtaining.

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.

(additives)

The multilayer film 1 of the present embodiment may be provided with known lubricants and additives as needed in the sealant layer 2 and the base material layer 3 for the purpose of preventing slipping and blocking and imparting antifogging properties. For the purpose of preventing sliding property and blocking, organic lubricants such as oleamide and erucamide, and inorganic lubricants such as silica, zeolite, and calcium carbonate can be mentioned. In addition, a known surfactant or the like can be suitably used to impart antifogging properties.

< method for producing multilayer film >

Next, an example of a method for producing the multilayer film 1 will be described.

The method for producing the multilayer film 1 is not particularly limited, and examples thereof include a feeding method in which a resin or the like as a raw material is melt-extruded by a plurality of extruders, a co-extrusion T-die method such as a multi-manifold method, an air-cooled or water-cooled co-extrusion blow molding method, and a lamination method. Among these, a method of forming a film by the co-extrusion T-die method is particularly preferable because it is excellent in controlling the thickness of each layer.

As the lamination method, a dry lamination method, an extrusion lamination method, a hot melt lamination method, a wet lamination method, a thermal lamination method, or the like, in which a single-layer sheet or film forming each layer is laminated with an appropriate adhesive, and a method using these methods in combination, can be used. Further, the lamination may be performed by a coating method.

< Package body >

Next, an example of a package using the multilayer film 1 will be described.

The package of the present embodiment includes the multilayer film and a polyethylene nonwoven fabric, and at least a part of the sealant layer of the multilayer film is heat-sealed to the surface of the nonwoven fabric.

The package of the present invention is configured to include the multilayer film of the present invention which can be heat-sealed with the polyethylene nonwoven fabric and has good easy peelability, and therefore the polyethylene nonwoven fabric should have desired easy peelability.

The polyethylene nonwoven fabric applicable to the package of the present embodiment is not particularly limited as long as it can be heat-sealed with the sealant layer and exhibits air permeability and characteristics (antibacterial properties) for preventing bacteria from entering the container when the nonwoven fabric is formed. Examples of Polyethylene (PE) constituting such nonwoven fabric include HDPE, LDPE, and LLDPE. Among them, HDPE is preferably used from the viewpoint of strength and heat sealability.

When the package of the present embodiment is used as a medical package, the polyethylene nonwoven fabric preferably has small holes to the extent that air permeability and antibacterial properties can be exhibited. Specifically, the fiber is preferably made of fibers in the range of 0.0001 to 20dtex, and the weight per unit area is 10 to 300g/m ² The nonwoven fabric of (1).

The package of the present embodiment can be used as a deep-drawn package by filling a content such as gauze after deep-drawing a base material, and covering a lid material thereon and heat-sealing the same. In particular, when the multilayer film is used as a base material of a deep-drawn package and a polyethylene nonwoven fabric is used as a lid material, a good deep-drawn package can be obtained.

The package of the present embodiment can be produced by bonding a multilayer film used as a base material and a polyethylene nonwoven fabric used as a lid material by a bonding method such as heat sealing. Specifically, the heat seal can be performed at a temperature in the range of 105 to 135 ℃. In the package of the present embodiment, the peel strength between the multilayer film 1 and the polyethylene nonwoven fabric is preferably 120 to 770(g/25mm), more preferably 120 to 750(g/25 mm). When the peel strength is not less than the lower limit of the above preferable range, the sealing property of the package can be obtained, and when the peel strength is not more than the upper limit, a good opening property can be obtained, and for example, an effect of suppressing fiber tearing or fuzzing at the time of peeling can be obtained.

The peel strength can be measured using a tensile tester (for example, TENSILON RTG-1310 manufactured by A & D Company) in accordance with JIS Z0237.

As described above, according to the configuration of the multilayer film of the present embodiment, the sealant layer provided to serve as the surface layer contains a resin having a melting point of 80 to 110 ℃, and therefore, the multilayer film can be heat-sealed with a polyethylene nonwoven fabric in a wide temperature range of 135 ℃ or less and has good peelability.

While the embodiments of the present invention have been described in detail with reference to the drawings, the specific configurations are not limited to the embodiments, and may be designed without departing from the spirit of the present invention. For example, the multilayer film 1 shown in fig. 1 has a structure in which the sealant layer 2 and the base material layer 3 are sequentially laminated, but this is merely an example and is not limited thereto. For example, as shown in fig. 2, the multilayer film according to an embodiment of the present invention may have a structure in which the sealant layer 2, the base layer 30, the base layer 31, the adhesive resin layer 4, and the pinhole-resistant layer 5 are sequentially laminated, and the adhesive resin layer 4 and the pinhole-resistant layer 5 may be alternately laminated in two layers or three or more layers may be alternately laminated.

In the multilayer film 1, a layer having another function may be newly provided between the layers or on the outermost layer on the side opposite to the sealant layer 2. For example, a resin layer made of an ethylene-vinyl alcohol copolymer resin may be provided from the viewpoint of imparting oxygen barrier properties to the multilayer film 1. In addition, from the viewpoint of providing strength to the multilayer film 1, a resin layer made of polypropylene 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.

Examples

The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited thereto.

< production of multilayer film >

(example 1)

A multilayer film having the structure shown in fig. 1 was produced by the following steps.

High-density polyethylene (HI-ZEX 3300F, product number manufactured by Prime Polymer Co., Ltd.) was prepared as a resin contained in the base layer 1.

Further, as resins contained in the sealant layer, an ethylene-vinyl acetate copolymer (EVA) resin (Du Pont-Mitsui Polychemicals Co., Ltd., product No. EVAFLEX V5714RC) having a melting point of 88 ℃ and a homopolypropylene (ホモプロピレン) (Prime Polymer Co., Ltd., product No. Y-400GP) having a melting point of 160 ℃ were prepared and kneaded in such a ratio that they became 60: 40.

Next, as shown in table 1 below, a multilayer film having a two-layer structure of the base layer 1/sealant layer in this order was produced by extrusion processing. The thickness (μm) of each layer of the obtained film was as shown in Table 1, and the total thickness was 100 μm.

The melting point of each resin was measured by differential scanning calorimetry (DSC 6220, SII) in accordance with JIS K-7121. Under a nitrogen atmosphere, the temperature was raised from 25 ℃ to 180 ℃ at a rate of 2 ℃/min, and after cooling to-40 ℃ at a rate of 50 ℃/min, the temperature was again raised to 180 ℃ at a rate of 2 ℃/min, and the melting point at the time of the second temperature rise was measured. When two or more melting point peaks are detected, the high temperature side is the melting point. The same applies hereinafter.

(example 2)

A multilayer film having a two-layer structure of the base layer 1/sealant layer in this order was produced by extrusion processing as shown in table 1 below in the same manner as in example 1 except that a resin obtained by kneading an ethylene-vinyl acetate copolymer (EVA) resin and homo-polypropylene at a ratio of 75:25 was used as the resin contained in the sealant layer. The thickness (μm) of each layer of the obtained film was as shown in Table 1, and the total thickness was 90 μm.

(example 3)

A multilayer film having a two-layer structure of the base layer 1/sealant layer in this order was produced by extrusion processing as shown in table 1 below, except that high-density polyethylene (product No. HI-ZEX2100J, manufactured by ltd., Prime Polymer co., ltd.) was prepared as the resin contained in the base layer 1. The thickness (μm) of each layer of the obtained film was as shown in Table 1, and the total thickness was 105 μm.

(example 4)

A multilayer film having a two-layer structure of the base layer 1/sealant layer in this order was produced by extrusion processing as shown in table 1 below in the same manner as in example 1 except that a resin obtained by kneading an ethylene-vinyl acetate copolymer (EVA) resin and homo-polypropylene at a ratio of 75:25 was used as the resin contained in the sealant layer. The thickness (μm) of each layer of the obtained film was as shown in Table 1, and the total thickness was 125 μm.

(example 5)

A multilayer film having a two-layer structure of a base layer 1/a sealant layer in this order was produced by extrusion processing as shown in table 1 below in the same manner as in example 1 except that a resin obtained by kneading an ethylene-vinyl acetate copolymer (EVA) resin and a homo-polypropylene at a ratio of 90:10 was used as the resin contained in the sealant layer. The thickness (μm) of each layer of the obtained film was as shown in Table 1, and the total thickness was 100 μm.

(example 6)

A multilayer film having a two-layer structure of the base layer 1/the sealant layer was prepared by extrusion processing as shown in table 1 below in the same manner as in example 1 except that high-density polyethylene (Prime Polymer Co., ltd.; product No.: HI-ZEX2100J) was prepared as the resin contained in the base layer 1, and an ethylene-vinyl acetate copolymer (EVA) resin (Ube-Maruzen polyethylene Co., ltd.; product No.: Ube polyethylene V315) having a melting point of 87 ℃ and a homopolypropylene (Prime Polymer Co., ltd.; product No.: Y-400GP) having a melting point of 160 ℃ were prepared as the resin used for the sealant layer and kneaded so as to have a ratio of 75: 25. The thickness (μm) of each layer of the obtained film was as shown in Table 1, and the total thickness was 90 μm.

(example 7)

As resins for the sealant layer, multilayer films having a two-layer structure of substrate layer 1/sealant layer were prepared by extrusion processing in the same manner as in example 1 except that an ethylene-ethyl acrylate copolymer (EEA) resin having a melting point of 93 ℃ (NUC Corporation, product number: EEA NUC-6170) and a homopolypropylene having a melting point of 160 ℃ (Prime Polymer co., ltd., product number: Y-400GP) were prepared and kneaded so as to have a ratio of 75:25, as shown in table 1 below. The thickness (μm) of each layer of the obtained film was as shown in Table 1, and the total thickness was 90 μm.

(example 8)

As resins for the sealant layer, multilayer films having a two-layer structure of a base layer 1/a sealant layer were prepared by extrusion processing in the same manner as in example 1 except that an ethylene-methyl methacrylate copolymer (EMMA) resin (manufactured by Japan PolyStyrene inc., product No. REXPEARL EB230X) having a melting point of 87 ℃ and a homopolypropylene (manufactured by Prime Polymer co., ltd., product No. Y-400GP) having a melting point of 160 ℃ were prepared and kneaded so as to have a ratio of 75:25, as shown in table 1 below. The thickness (μm) of each layer of the obtained film was as shown in Table 1, and the overall thickness was 95 μm.

(example 9)

As a resin used for the sealant layer, a multilayer film having a two-layer structure of a base layer 1/a sealant layer in this order was prepared by extrusion processing in the same manner as in example 1 except that an ethylene-methyl methacrylate copolymer (EMMA) resin (Sumitomo Chemical co., ltd., product No. ACRYFT WH303-F) having a melting point of 89 ℃ and a homo polypropylene (Prime Polymer co., ltd., product No. Y-400GP) having a melting point of 160 ℃ were prepared and kneaded so as to have a ratio of 75:25, as shown in table 1 below. The thickness (μm) of each layer of the obtained film was as shown in Table 1, and the total thickness was 100 μm.

(example 10)

As the resin contained in the base layer 1, a high-density polyethylene (print Polymer co., ltd., product number: HI-ZEX2100J), an ethylene-vinyl acetate copolymer (EVA) resin (Du Pont-Mitsui polychemics co., ltd., product number: EVAFLEX V5714RC) having a melting point of 88 ℃ and a homopolypropylene (Sumitomo Chemical co., ltd., product number: nobel WF836DG3) having a melting point of 158 ℃ were prepared, and kneaded so as to have a ratio of 75:25, and a multilayer film having a two-layer structure of the base layer 1/the sealant layer in this order was prepared by extrusion processing as shown in table 1 below in the same manner as in example 1. The thickness (μm) of each layer of the obtained film was as shown in Table 1, and the total thickness was 105 μm.

(example 11)

A multilayer film having a two-layer structure of the base layer 1/the sealant layer was prepared by extrusion processing in the same manner as in example 1 except that high-density polyethylene (Prime Polymer co., ltd., product No. HI-ZEX2100J) was prepared as a resin contained in the base layer 1, an ethylene-vinyl acetate copolymer (EVA) resin (Du Pont-Mitsui polychemics co., ltd., product No. EVAFLEX V5714RC) having a melting point of 88 ℃ and a homopolypropylene (Sumitomo Chemical co., ltd., product No. nobelene FH2311) having a melting point of 148 ℃ were prepared as a resin used for the sealant layer, and the resins were kneaded so as to have a ratio of 75: 25. The thickness (μm) of each layer of the obtained film was as shown in Table 1, and the total thickness was 105 μm.

(example 12)

As the resin contained in the base layer 1, a multilayer film having a two-layer structure of the base layer 1/sealant layer was prepared by extrusion processing in the same manner as in example 1 except that high-density polyethylene (Prime Polymer co., ltd., product number: HI-ZEX2100J), a linear low-density polyethylene resin (neblene 8402, product number: sabi corporation) having a melting point of 94 ℃ and a homopolypropylene (Prime Polymer co., ltd., product number: Y-400GP) having a melting point of 160 ℃ were prepared as resins for the sealant layer, and these were kneaded so as to have a ratio of 95: 5. The thickness (μm) of each layer of the obtained film was as shown in Table 1, and the total thickness was 90 μm.

(example 13)

A multilayer film having the structure shown in fig. 2 was produced by the following steps.

First, as a resin contained in the pin-resistant layer, 6-nylon (Ny) (UBE INDUSTRIES, ltd. product No. 1022B) was prepared.

As a resin contained in the adhesive resin layer (hereinafter, simply referred to as "adhesive layer"), an adhesive polyethylene resin (product number: NF536, manufactured by Mitsui Chemicals, inc.) was prepared.

High-density polyethylene (HI-ZEX 3300F) was prepared as a resin contained in the base layer 1, and linear low-density polyethylene (LLDPE) resin (ELITE 5220G, product number, manufactured by Dow Inc.) was prepared as a resin contained in the base layer 2.

Further, as resins contained in the sealant layer, an ethylene-vinyl acetate copolymer (EVA) resin (Du Pont-Mitsui Polychemicals Co., Ltd., product No. EVAFLEX V5714RC) having a melting point of 88 ℃ and a homopolypropylene (Prime Polymer Co., Ltd., product No. Y400-GP) having a melting point of 160 ℃ were prepared and kneaded in such a manner that the ratio thereof was 75: 25.

Next, as shown in table 1 below, a multilayer film having a five-layer structure was produced by extrusion processing in the order of the pinhole-resistant layer/adhesive layer/substrate layer 2/substrate layer 1/sealant layer. The thickness (μm) of each layer of the obtained film was as shown in Table 1, and the total thickness was 120 μm.

(example 14)

A multilayer film having a five-layer structure of a needle-hole-resistant layer/adhesive layer/base material layer 2/base material layer 1/sealant layer in this order was prepared in the same manner as in example 13 except that ethylene-vinyl acetate copolymer (EVA) resin having a melting point of 88 ℃ (Du Pont-Mitsui polychemics Co., ltd., product No.: EVAFLEX V5714RC), homopolypropylene having a melting point of 160 ℃ (Prime Polymer Co., ltd., product No.: Y400-GP), and low-density polyethylene (LDPE) resin (Ube-Maruzen Polyethlene Co., ltd., product No.: UMERIT 82105M) were prepared and kneaded in such a manner that they were in a ratio of 71:24:5, and a multilayer film having a five-layer structure of a needle-hole-resistant layer/adhesive layer/base material layer 2/base material layer 1/sealant layer was produced by extrusion processing as shown in table 1 below. The thickness (μm) of each layer of the obtained film was as shown in Table 1, and the total thickness was 120 μm.

(example 15)

A multilayer film having a five-layer structure of a needle-hole-resistant layer/adhesive layer/base layer 2/base layer 1 in this order was prepared by extrusion processing in the same manner as in example 13 except that an ethylene-vinyl acetate copolymer (EVA) resin having a melting point of 88 ℃ (Du Pont-Mitsui polychemics Co., ltd., product No.: EVAFLEX V5714RC), a homopolypropylene having a melting point of 160 ℃ (Prime Polymer Co., ltd., product No.: Y400-GP), and a low-density polyethylene (LDPE) resin (Ube-Maruzen Polyethlene Co., ltd., product No.: UMERIT 82105M) were prepared and kneaded in such a manner that they were in a ratio of 81:14:5, and a multilayer film having a five-layer structure of a needle-hole-resistant layer/adhesive layer/base layer 2/base layer 1 in this order was prepared as shown in table 1 below. The thickness (μm) of each layer of the obtained film was as shown in Table 1, and the total thickness was 120 μm.

Comparative example 1

Further, as a resin contained in the sealant layer, a Linear Low Density Polyethylene (LLDPE) resin (Prime Polymer Co., Ltd., product No. ULTZEX 2022L) having a melting point of 120 ℃ was prepared.

Next, as shown in table 1 below, a multilayer film having a two-layer structure of the base layer 1/sealant layer in this order was produced by extrusion processing. The thickness (μm) of each layer of the obtained film was as shown in Table 1, and the total thickness was 105 μm.

Comparative example 2

A multilayer film having a two-layer structure of the order of base layer 1/sealant layer was prepared by extrusion processing as shown in Table 1 below, except that an ethylene-vinyl acetate copolymer (EVA) resin (TOSOH CORPORATION, product No.: Ultra cene 534) having a melting point of 98 ℃ was prepared as the resin contained in the sealant layer, in the same manner as in comparative example 1. The thickness (μm) of each layer of the obtained film was as shown in Table 1, and the total thickness was 105 μm.

Comparative example 3

A multilayer film having a two-layer structure of the base layer 1/sealant layer sequence was produced by extrusion processing as shown in table 1 below in the same manner as in comparative example 1 except that an ethylene-vinyl acetate copolymer (EVA) resin (Du Pont-Mitsui polychemics co., ltd., product No.: EVAFLEX V5714RC) having a melting point of 88 ℃ was prepared as the resin contained in the sealant layer. The thickness (μm) of each layer of the obtained film was as shown in Table 1, and the total thickness was 105 μm.

Comparative example 4

First, as a resin contained in the pin-resistant layer, nylon (UBE INDUSTRIES, ltd., product No. 1022B) was prepared.

As a resin contained in the adhesive layer, an adhesive polyethylene resin (product No. NF536, manufactured by Mitsui Chemicals, inc.) was prepared.

An Ionomer (ION) resin (Du Pont-Mitsui Polychemicals co., ltd., product number: Himilan 1855) was prepared as a resin contained in the base layer 1.

Further, as a resin contained in the sealant layer, an ethylene-vinyl acetate copolymer (EVA) resin (Du Pont-Mitsui polychemics Co., Ltd., product No. EVAFLEX V5714RC, manufactured by Ltd.) having a melting point of 88 ℃ was prepared.

Next, as shown in table 1 below, a multilayer film having a five-layer structure in the order of the pinhole-resistant layer/adhesive layer/substrate layer 1/sealant layer was produced by extrusion processing. The thickness (μm) of each layer of the obtained film was as shown in table 1, and the total thickness was 100 μm.

Comparative example 5

A multilayer film having a two-layer structure of the base layer 1/sealant layer in this order was produced by extrusion processing as shown in table 1 below, except that a linear low-density polyethylene (LLDPE) resin (Prime Polymer co., ltd., product number: evole SP0540) having a melting point of 90 ℃ was prepared as the resin contained in the sealant layer. The thickness (μm) of each layer of the obtained film was as shown in Table 1, and the total thickness was 110 μm.

< evaluation method >

The multilayer films obtained in examples and comparative examples were stacked on a medical packaging material (manufactured by Du Pont, "Tyvek (registered trademark) 4058B") such that the Tyvek side was on the hot plate side, and a Teflon (registered trademark) sheet was placed thereon, followed by sealing using an automatic sealing machine under the following conditions. The film was peeled in the MD direction of the film, and evaluated.

Sealing pressure: 11.2kgf/cm ² (1.1MPa)

Sealing time: 3.5 seconds

Sealing temperature: 100. 110, 120 and 130 ℃ (at intervals of 10 ℃, 4 conditions)

The evaluation samples of all the packages obtained in examples and comparative examples were subjected to the evaluation of heat sealability and the evaluation of peelability.

(evaluation of Heat sealability)

The heat sealability was evaluated by measuring the peel strength at a seal width of 25mm using a tensile tester (manufactured by A & D Company, TENSILON RTG-1310). At a peeling speed of 200 mm/min. Table 1 shows the peel strength of the evaluation samples prepared at each sealing temperature for the examples and comparative examples.

(evaluation of peelability)

The lid material and the base material of the package as an evaluation sample were torn to evaluate the peelability.

The peeled surfaces of the lid member and the base member were observed and judged by the following criteria. Table 1 shows the results of the evaluation of the peelability of the evaluation samples produced in the examples and comparative examples at the respective sealing temperatures.

And (3) judging A: the cover material is not broken and the fibers are not attached to the substrate. And B, judgment: the lidstock is broken or the fibers are attached to the substrate.

As shown in table 1, in examples 1 to 15, the sealant layer of the multilayer film configured as a substrate contained the first resin having a melting point of 80 to 110 ℃ and the second resin having a melting point of 130 to 200 ℃, and therefore, in all the evaluation samples having a sealing temperature of 110 to 130 ℃, it was confirmed that the peel strength was in the range of 120 to 770g/25mm, heat sealing was possible in a wide temperature range of 135 ℃ or less, and heat sealability was excellent. In all the evaluation samples with sealing temperature of 100-130 ℃, the cover material is not broken during peeling, and the adhesion of the fiber to the substrate is small, so that the peeling property is excellent.

In contrast, in comparative examples 1 to 5, the sealant layer was composed of one resin having a melting point of 80 to 120 ℃, and therefore, in any of the evaluation samples having a sealing temperature of 100 to 130 ℃, it was confirmed that the adhesion of the fibers to the substrate was large and the releasability was poor. Also, in all the samples having the sealing temperature of 130 ℃, it was confirmed that the peel strength exceeded 800g/25 mm. In particular, in comparative examples 3 and 4, it was confirmed that the peel strength exceeded 800g/25mm in all the evaluation samples exceeding the sealing temperature by 110 ℃. In comparative examples 1, 2 and 5, the peel strength was less than 50g/25mm in the evaluation sample at 100 ℃.

Industrial applicability

A multilayer film which can be heat-sealed to a polyethylene nonwoven fabric in a wide temperature range of 135 ℃ or lower and has excellent releasability can be provided.

Description of reference numerals

1-multilayer film, 2-sealant layer, 3-base material layer, 30-base material layer 1, 31-base material layer 2, 4-adhesive resin layer, 5-pinhole-resistant layer.

Claims

1. A package comprising a multilayer film as a base material and a polyethylene nonwoven fabric as a lid material,

at least a part of the sealant layer of the multilayer film is heat-sealed on the surface of the nonwoven fabric,

the multilayer film comprises at least a sealant layer provided to serve as a surface layer and a base material layer provided adjacent to the sealant layer and containing a polyethylene resin,

the sealant layer contains at least a first resin having a melting point of 80 to 110 ℃ and a second resin having a melting point of 130 to 200 ℃,

the first resin contains an ethylene-vinyl acetate copolymer,

the second resin contains a homo-polypropylene,

the multilayer film can be heat-sealed with a polyethylene nonwoven fabric at 110 ℃.

2. The package of claim 1,

the sealant layer contains 50 to 99 mass% of a first resin and 1 to 50 mass% of a second resin.

3. The package according to claim 1 or 2,

the substrate layer contains a high-density polyethylene resin.

4. The package according to any one of claims 1 to 3,

the thickness ratio of the sealant layer to the base material layer is in the range of 1:0.5 to 1: 10.

5. The package according to any one of claims 1 to 4,

the peel strength between the multilayer film and the non-woven fabric is 120-770 g/25 mm.