TW201924937A - Easy-open layered film, and easy-open laminate film - Google Patents

Abstract

This easy-open layered film comprises a base material layer and a heat seal layer, the base material film has a resin layer containing a propylene resin (a1) with a melt tension at 230 DEG C of 0.03-0.40 N, and the content of said propylene resin (a1) is 5-50 mass% of the resin component contained in the base material layer. By means of said easy-open layered film and an easy-open laminate film using the same, it is possible to favorably suppress fluidity of the resin component at high temperatures, and it is possible to simultaneously achieve both favorable heat sealing properties and easy-opening properties when sealed at a high sealing temperature.

Description

   Easy-opening laminated film, easy-opening multilayer film   

The present invention relates to an easily-openable laminated film, which can appropriately package a packaged object, and can be used for encapsulation of an opening portion of a packaging container that can be easily opened.

In the past, it has been widely used as a package for various foods, medical appliances, and the like: a film that can be easily opened is made of a film that can be easily opened. As such a packaging form, for example, it is disclosed that an easily-openable film is formed into a bag-like package having an opening (see Patent Document 1), and an opening of a packaging container having an opening is sealed with an easily-openable film. Package (see Patent Document 2) and the like.

    [Prior technical literature]         [Patent Literature]    

[Patent Document 1] Japanese Patent Laid-Open No. 2015-120249

[Patent Document 2] Japanese Patent Laid-Open No. 2016-210063

The films used in these packages must be easily opened when they are opened. However, if the package is opened due to shock during distribution in food, medical appliances, etc., the packaged product will become unusable. Easy-opening film that can be packaged at high sealing temperatures. In addition, the same problem occurs when a breakage occurs due to an impact during circulation, etc., and the demand for improving the impact resistance is also high.

The problem to be solved by the present invention is to provide an easily-openable film that has suitable heat-sealability even at a high sealing temperature and has good openability at the time of opening.

In addition to the problems described above, the present invention also aims to provide an easily-openable film having suitable impact resistance.

The present invention solves the above-mentioned problem by an easy-opening laminated film, which is an easy-opening laminated film having a substrate layer and a heat-sealing layer, wherein the aforementioned substrate layer has a melt tension of 230 ° C The resin layer of the propylene-based resin (a1) is 0.03 to 0.40 N, and the content of the propylene-based resin (a1) is 5 to 50% by mass of the resin component contained in the base material layer.

The easily-openable laminated film of the present invention can be suitably used by containing an acrylic resin having a melt tension of 0.03 to 0.40 N in the substrate layer in the easily-openable laminated film having a substrate layer and a heat-sealing layer. Suppresses the fluidity of the resin component at high temperature, and can have suitable heat-sealability and easy-opening property even when packaged at high sealing temperature.

    [Form of Implementing Invention]    

The easy-opening laminated film of the present invention has a base material layer and a heat-sealable layer. The base material layer has a resin layer containing a polypropylene resin (a1) having a melt tension of 230 ° C of 0.03 to 0.40N, and a polypropylene resin (a1). The content is 5-50% by mass of the easily-openable laminated film in the resin component contained in the base material layer.

    [Substrate layer]    

The base material layer used in the present invention contains a propylene-based resin (a1) having a melt tension of 230 ° C. of 0.03 to 0.40 N. The propylene resin (a1) of the melt tension has a structure in which long chain branches are introduced into the main chain of the polypropylene resin, and the melt tension is improved. In the present invention, by using the acrylic resin in the base material layer, the flow of the base material layer at the time of high-temperature sealing can be suppressed, an excessive increase in peel strength can be suppressed, and appropriate peelability can be achieved. The melt tension of the propylene resin (a1) is preferably 0.05 to 0.40N, and more preferably 0.10 to 0.40N.

The content of the propylene-based resin (a1) in the base material layer is 5 to 50% by mass, preferably 5 to 40% by mass, more preferably 8 to 30% by mass, and further more preferably 5 to 50% by mass of the resin components contained in the base layer. It is preferably 8 to 25% by mass. By setting the content of the propylene-based resin (a1) within this range, it is possible to achieve appropriate peelability by suppressing the fluidity of the base material layer at the time of high-temperature sealing.

As the resin other than the above-mentioned propylene-based resin (a1) used for the base material layer, various resins used for packaging films can be used, and among these, olefin-based resins can be preferably used. As the olefin-based resin, a propylene-based resin or an ethylene-based resin other than the propylene-based resin can be used. Examples of the propylene-based resin include a propylene homopolymer, and a copolymer of propylene with an α-olefin such as ethylene and butene-1. As the copolymer, any of a random copolymer and a block copolymer can be used. In addition, as the vinyl resin, very low density polyethylene (VLDPE), linear low density polyethylene (LLDPE), low density polyethylene (LDPE), linear medium density polyethylene (LMDPE), and medium density polymer can be used. Either a polyethylene resin such as ethylene (MDPE) or an ethylene-vinyl acetate copolymer (EVA).

When an olefin-based resin is used as the resin other than the propylene-based resin (a1), the content thereof is preferably 70 to 95% by mass, and more preferably 80 to 95% by mass, among the resin components contained in the base material layer. By using an olefin-based resin other than the propylene-based resin (a1) within this range, it becomes easy to obtain suitable film-forming properties.

As the resin other than the above-mentioned propylene-based resin (a1), it is more preferable to use a propylene-based resin, and it is more preferable to use a melt flow rate (230 ° C, 21.18N) of 0.5 to 10 g / 10. The propylene resin (a2) is preferably 0.5 to 8 g / 10 minutes, more preferably 0.5 to 5 g / 10 minutes. By using the propylene resin (a1) in combination with the propylene resin (a1), it is possible to more appropriately suppress fluidity during high-temperature sealing, and it becomes easy to have both excellent heat-sealing properties and easy-opening properties. In addition, by using a propylene-based block copolymer resin as the propylene-based resin (a2), it becomes particularly easy to appropriately adjust these heat-sealing properties and easy-opening properties.

When an acrylic resin (a2) is used, the content is preferably set to 50% by mass of the resin component contained in the base material layer from the viewpoint of easily obtaining suitable heat-sealing properties, easy-opening properties, film-forming properties, and the like. Above, it is preferably 70 to 95% by mass, and more preferably 80 to 95% by mass.

In the base material layer used in the present invention, it is also preferable to use a thermoplastic elastomer (a3) as a resin component. Examples of the thermoplastic elastomer (a3) include polyethylene-based elastomers, polypropylene-based elastomers, and butene-based elastomers. Among them, an ethylene-based elastomer can be preferably used, and a copolymer of ethylene and an α-olefin having 3 to 8 carbon atoms can be particularly preferably used.

When a thermoplastic elastomer (a3) is used, its content is preferably set to 5 to 30% by mass, and more preferably 10 to 20% by mass of the resin component contained in the base material layer. By using a thermoplastic elastomer (a3) in this range, it becomes easy to achieve suitable impact resistance.

In the base material layer used in the present invention, a resin other than the olefin-based resin and the thermoplastic elastomer may be used in combination. Examples of the other resins include ethylene-methyl methacrylate copolymer (EMMA), ethylene-ethyl acrylate copolymer (EEA), ethylene-methyl acrylate (EMA) copolymer, and ethylene-ethyl acrylate- Maleic anhydride copolymer (E-EA-MAH), ethylene-acrylic acid copolymer (EAA), ethylene-methacrylic acid copolymer (EMAA), and other ethylene-based copolymers; further use: ethylene-acrylic acid copolymer Ionic polymers, ionic polymers of ethylene-methacrylic acid copolymers, etc.

When the other resins are used, the content is preferably 30% by mass or less of the resin component contained in the base material layer, more preferably 20% by mass or less, and even more preferably 10% by mass or less.

In the base material layer, various additives and the like may be suitably used in combination in addition to the resin components described above. As the additive, for example, a lubricant, an antiblocking agent, an ultraviolet absorber, a light stabilizer, an antistatic agent, an anti-fogging agent, and a coloring agent can be suitably used. When these additives are used, it is preferably used in an amount of about 2 parts by mass or less, more preferably about 0.01 to 1 part by mass, based on 100 parts by mass of the resin component used in the substrate layer.

    [Heat Sealing Layer]    

As the heat-sealing layer used in the present invention, various heat-sealing layers used in packaging films can be suitably used. The unsealing form of the easy-opening laminated film of the present invention can also be caused by peeling between the base material layer and the heat-sealing layer, or caused by the aggregation and destruction of the heat-sealing layer, etc., but it is made in the heat The layer having a destructive agglutination layer can be adapted to the shape of various containers, and is therefore preferred.

From the standpoint of easy adhesion to the base material layer, the heat-sealing layer used in the present invention preferably uses an olefin-based resin as the main resin component. As the olefin-based resin, the above-mentioned propylene-based resin and ethylene-based resin can be preferably used.

As the propylene-based resin and the vinyl-based resin used in the heat-sealing layer, the propylene-based resin and the vinyl-based resin exemplified in the substrate layer described above can be suitably used. Among these, as the propylene-based resin, a propylene-ethylene random copolymer and a propylene-ethylene-butene-1 random copolymer are more preferable. Further, as the vinyl-based resin, high-density polyethylene (HDPE), linear low-density polyethylene (LLDPE), low-density polyethylene (LDPE), and the like can be preferably used.

Among the vinyl resins, polyethylene having a density of 0.950 g / cm ³ or more can be preferably used, and polyethylene having a density of 0.955 g / cm ³ or more can be preferably used.

Because the oil resistance is good, the packing strength of the package containing no oily food is reduced due to heat sterilization, and it is difficult to cause bag breakage. Therefore, the content of the olefin-based resin in the heat-sealing layer is preferably 90% by mass or more, more preferably 95% by mass.

As the heat-sealing layer used in the present invention, it is preferable to use a combination of a propylene-based resin and an ethylene-based resin among the olefin-based resins. By using these resins in combination, it becomes easy to achieve suitable unsealing properties due to the destructiveness of the heat-sealing layer.

When a polypropylene resin and a vinyl resin are used together, it is preferably used in combination: the melt flow rate (230 ° C, 21.18N) is preferably 2 to 15 g / 10 min, and more preferably 4 to 10 propylene resin; and the melt flow The rate (190 ° C, 21.18N) is preferably 2 to 25 g / 10 min, and more preferably 5 to 20 g / 10 min. The respective contents are preferably 30 to 70% by mass of propylene resin, 30 to 70% by mass of ethylene resin, more preferably 40 to 60% by mass of propylene resin, and ethylene resin It is 40 to 60% by mass.

The polypropylene resin (a1) may be contained in the heat-sealing layer, and the content is preferably set to 30% or less, and more preferably set to 20% or less.

When using a resin other than the olefin-based resin as the resin component in the heat-sealable layer, ethylene-methyl methacrylate copolymer (EMMA), ethylene-ethyl acrylate copolymer (EEA), and ethylene-acrylic acid Ethylene methyl ester (EMA) copolymer, ethylene-ethyl acrylate-maleic anhydride copolymer (E-EA-MAH), ethylene-acrylic acid copolymer (EAA), ethylene-methacrylic acid copolymer (EMAA) and other ethylene Copolymers, etc .; Further, ionic polymers of ethylene-acrylic acid copolymers, ionic polymers of ethylene-methacrylic acid copolymers, and the like can be used.

When other resins other than the olefin-based resin are used, the content thereof is preferably used at 20% by mass or less in the resin component contained in the heat-sealing layer, and more preferably 10% by mass or less.

In the heat-sealing layer, in addition to the above-mentioned resin components, various additives and the like may be suitably used in combination. As the additive, for example, a lubricant, an anti-caking agent, an ultraviolet absorber, a light stabilizer, an antistatic agent, an anti-fogging agent, a coloring agent, and the like can be suitably used. When these additives are used, it is preferably used in an amount of about 2 parts by mass or less, more preferably about 0.01 to 1 part by mass, based on 100 parts by mass of the resin component used in the heat-sealable layer.

    [Easy-opening laminated film]    

The easily-openable laminated film of the present invention is a film in which the above-mentioned substrate layer and the heat-sealed layer are laminated. As described above, the easily-openable film having such a structure can have both suitable heat-sealing properties and easy-opening properties even when sealed at a high temperature.

The total thickness of the easy-opening laminated film of the present invention is preferably 20 to 100 μm, and more preferably 20 to 60 μm. By setting it as this thickness, suitable heat-sealability can be achieved.

The easy-opening multilayer film of the present invention preferably has a thickness ratio of 70 to 95%, more preferably 80 to 95%, relative to the thickness of the base material layer of the film. The thickness ratio of the heat-sealing layer is preferably 5 to 30%, and more preferably 5 to 20%. By setting this thickness ratio, it becomes easy to obtain a suitable opening property.

Further, in the easily-openable laminate film according to the present invention, the base material layer may be composed of a single layer, or may be formed of a plurality of layers. Even when the base material layer includes two or more layers, by setting the content of the propylene resin (a1) in the base material layer to 5 to 50% by mass of the resin components contained in the base material layer, a suitable value can be achieved. Heat sealability and easy opening.

In addition, the easy-opening laminated film of the present invention is a so-called sealant film used in various packaging applications, and is a film formed by laminating a heat-sealing layer and a substrate. The base material layer in this configuration refers to a layer laminated on a heat-sealable layer. When a later-described multi-layered base material is provided on the base material layer and used as a multi-layered film, it becomes and adheres to the heat-sealable layer and multi-layered base. The layer between the adhesive layers of the wood. As the base material layer, in addition to the layer containing the olefin-based resin as a main component described above, various functional layers may be included, and a structure containing a layer containing an olefin-based resin as a main component is preferably used.

When the base material layer is made into a plurality of layers, all the layers constituting the base material layer may be made into a resin layer containing a propylene resin (a1) (hereinafter referred to as a layer (A1)), or a layer containing a propylene resin The layer of (a1) and the layer containing no propylene resin (a1) (hereinafter may be referred to as a layer (A2)).

When the base material layer is formed of a plurality of layers, when the average content of the propylene resin (a1) in the resin component contained in the layer containing the propylene resin (a1) is 50% by mass or less, The total thickness ratio of the resin layer containing the propylene resin (a1) is preferably 30% or more, more preferably 40 to 100%, and particularly preferably 50 to 100%. By setting the thickness ratio of the resin layer containing the propylene-based resin (a1) within this range, it becomes easy to obtain suitable unsealing properties.

On the other hand, in the case where a layer including a propylene-based resin (a1) as a resin component is provided, the average content of the propylene-based resin (a1) in the resin component included in the layer containing the propylene-based resin (a1) is greater than 50. At mass%, the total thickness ratio of the resin layer containing the propylene resin (a1) in the base material layer is preferably less than 30%, more preferably 5 to 20%, and still more preferably 5 to 15%.

As the layer (A2), various functional layers used for a packaging film, a resin layer containing an olefin-based resin as a main resin component, and the like can be suitably used depending on the application. Among them, a resin layer containing an olefin-based resin as a main resin component can be preferably used from the viewpoint of ensuring easy interlayer adhesion with the layer (A1) and the like. As an example of such a layer (A2), a resin layer using one or two types of the resins (a1) to (a3) described above can be preferably exemplified.

Examples of the layer configuration in the case where the base material layer is made into a plurality of layers include a structure in which a layer (A1) is laminated into two or three layers, a layer (A1) / layer (A2), a layer (A1) / layer (A2) ) / Layer (A1), layer (A2) / layer (A1) / layer (A2), etc.

From the perspective of easily identifying the contents of the package, the haze of the easy-opening laminated film of the present invention is preferably 20% or less, more preferably 15% or less, and 10% or less is further more preferable.

    [Manufacturing method of easy-opening laminated film]    

The method for producing the easy-opening laminated film of the present invention is not particularly limited, and examples thereof include heating and melting each resin or resin mixture used in each layer in a separate extruder, and co-extrusion. The multilayer film method, feed block method and other methods are used to laminate the heat-seal layer / intermediate layer / surface layer in a molten state, and then form the film into a thin film by inflation, T-shaped die · cooling roller method, etc. Method of extrusion. The co-extrusion method is relatively free to adjust the thickness ratio of each layer, and it is preferable to obtain a laminated film with excellent hygiene and cost effectiveness. In the case of a resin having a large difference in melting point and Tg, the appearance of the film may be deteriorated during co-extrusion, and it may become difficult to form a uniform layer structure. In order to suppress such deterioration, a T-shaped die ‧ chill roll method capable of performing melt extrusion at a relatively high temperature is preferred.

Furthermore, when printing or the like is performed on the surface of the substrate layer, it is preferable to apply a surface treatment to the substrate layer in order to improve the adhesion with the printing ink and the like. Examples of such a surface treatment include corona treatment, plasma treatment, chromic acid treatment, flame treatment, hot air treatment, ozone and ultraviolet treatment, surface oxidation treatment such as sandblasting, and surface unevenness treatment such as sandblasting. Corona treatment is preferred. .

    [Multilayer film]    

The multi-layer film of the present invention is a film in which a multi-layer substrate is laminated on a substrate layer of the aforementioned easy-opening laminated film. The multi-layer substrate is not particularly limited, and it is preferable to stretch the substrate film from the viewpoints of ensuring strength that does not normally crack, ensuring heat resistance during heat sealing, and improving designability of printing. As the stretched base film, a biaxially stretched polyester film, a biaxially stretched nylon film, a biaxially stretched polypropylene film, or the like can be used. From the viewpoints of breaking strength, transparency, etc., the biaxially stretched polymer is more preferable. Ester film and biaxially stretched nylon film. In addition, as the substrate film, a fragile treatment or an antistatic treatment may be applied according to necessity.

The manufacturing method of the multilayer film of the present invention is not particularly limited, and examples thereof include a method of laminating a multilayer substrate on the substrate layer of the laminated film. As the method for laminating the multi-layer substrate in the aforementioned laminated film of the present invention, for example, a dry layer method, a thermal layer method, a multi-layer extrusion coating method, etc. may be mentioned. Among them, the dry layer method is more preferable. In addition, in the dry layer method, examples of the adhesive used when laminating the laminated film and the multi-layer substrate include a polyether-polyurethane-based adhesive and a polyester-polyurethane. Ester-based adhesives and the like. In addition, it is preferable to apply a corona discharge treatment to the surface of the surface layer before laminating the co-extruded laminated film and the substrate of the present invention to improve the adhesion to the substrate.

    [Packing]    

The easily-openable laminate film and multilayer film of the present invention can be suitably used as various packaging materials. It can be suitably used especially for a jelly, tofu, and rice container.

As the polyolefin-based resin used in the packaging container, polypropylene is preferred, and examples thereof include homopolypropylene, propylene-ethylene copolymer, propylene-butene-1 copolymer, and propylene-ethylene-butene-1. A homopolymer of propylene such as a copolymer or a copolymer of propylene and an α-olefin. Among these polypropylene resins, as long as the content of the propylene monomer units in the polymer is 70 mol% or more, sufficient sealing strength can be obtained, and therefore, it is preferable.

As the heat cover of the opening of the packaging container, the polyolefin resin is preferably contained in a proportion of 60% by mass or more, and more preferably contained in a proportion of 80% by mass or more. As long as the content of the polyolefin-based resin of the heat cover is in the aforementioned range, a particularly suitable seal strength is easily obtained, and therefore, it is preferable. In the heat cover, the resin that can be used in combination with the polyolefin resin is not particularly limited as long as it is a resin that has good compatibility with the polypropylene resin and does not hinder heat sealing, and examples thereof include ethylene. Polyethylene resins such as homopolymers and ethylene-α-olefin copolymers.

In addition, it is also preferable to use polyethylene terephthalate and polystyrene in the openings as packaging containers for resins other than the above.

    [Example]    

The present invention will be described in more detail with examples and comparative examples. Unless otherwise specified, "parts" and "%" are quality standards.

    (Example 1)    

Each of the resins described below was used as the resin component of each of the layers forming the base material layer (A) and the heat-sealing layer (B) to prepare a resin mixture to form each layer. The base material layer (A) has a two-layer structure including a base material layer (A1) and a base material layer (A2). The resin mixture forming each layer was separately supplied to three extruders to form an average thickness of each layer of the laminated film formed as the base material layer (A1) / base material layer (A2) / seal layer (B) as 15 μm / 30 μm / 5 μm. In a manner, co-extrusion is performed by a T-die at an extrusion temperature of 270 ° C, and cooling is performed with a water-cooled metal cooling roll at 40 ° C to form a laminated film having a total thickness of 50 μm. Next, a corona discharge treatment was applied to the surface of the substrate layer (A1) of the obtained laminated film so that the wetting tension became 44 mN / m to obtain a laminated film.

Base material layer (A1): 90 parts by mass of a propylene-based copolymer (1) (density 0.90 g / cm ³ , MFR 3.0 g / 10min) (hereinafter referred to as PP (1)), and high melt tension with 10 parts by mass A mixture of polypropylene (1) (density 0.91 g / cm ³ , MFR 1.1 g / 10 min, melt tension 0.26 N) (hereinafter referred to as HMS-PP (1)).

Base material layer (A2): 90 parts by mass of a propylene-based copolymer (2) (density 0.90 g / cm ³ , MFR 2.0 g / 10min) (PP (2)), and 10 parts by mass of HMS-PP (1) Of a mixture.

Heat-sealing layer (B): 50 parts by mass of a propylene-ethylene copolymer (1) (density 0.90 g / cm ³ , MFR 7.0 g / 10min) (hereinafter referred to as COPP (1)), and a high density of 50 parts by mass Blend of polyethylene (density 0.96 g / cm ³ , MFR 8.0 g / 10 min) (HDPE (1)).

    (Example 2)    

A laminated film was obtained in the same manner as in Example 1 except that the resin component of the resin mixture used in the base material layer (A1) and the base material layer (A2) was set to the following.

Base material layer (A1): 80 parts by mass of PP (1), 20 parts by mass of HMS-PP (1)

Base material layer (A2): 80 parts by mass of PP (2), 20 parts by mass of HMS-PP (1)

    (Example 3)    

A laminated film was obtained in the same manner as in Example 1 except that the resin component of the resin mixture used in the base material layer (A1) and the base material layer (A2) was set to the following.

Base material layer (A1): 80 parts by mass of PP (1), 20 parts by mass of high melt tension polypropylene (2) (density 0.91g / cm ³ , MFR 2.5g / 10min, melt tension 0.15N) (hereinafter referred to as (For HMS-PP (2))

Base material layer (A2): 80 parts by mass of PP (2), 20 parts by mass of HMS-PP (2)

    (Example 4)    

A laminated film was obtained in the same manner as in Example 1 except that the resin component of the resin mixture used in the base material layer (A1) and the base material layer (A2) was set to the following.

Base material layer (A1): 80 parts by mass of PP (1), 20 parts by mass of high melt tension polypropylene (3) (density 0.91g / cm ³ , MFR 9.0g / 10min, melt tension 0.05N) (hereinafter referred to as (For HMS-PP (3))

Base material layer (A2): 80 parts by mass of PP (2), 20 parts by mass of HMS-PP (3)

    (Example 5)    

A laminated film was obtained in the same manner as in Example 2 except that the resin component of the resin mixture used in the heat-sealing layer (B) was set to the following.

Heat-sealing layer (B): 60 parts by mass of a propylene-ethylene copolymer (2) (density: 0.90 g / cm ³ , MFR 10.0 g / 10min) (hereinafter referred to as COPP (2)), 40 parts by mass of HDPE (1 )

    (Example 6)    

A laminated film was obtained in the same manner as in Example 1 except that the resin component of the resin mixture used in the substrate layer (A1) and the substrate layer (A2) was set to the following.

Base material layer (A1): 65 parts by mass of PP (1), 15 parts by mass of HMS-PP (1), 20 parts by mass of thermoplastic elastomer (1) (ethylene-butene copolymer: density 0.89 g / cm ³ , MFR 1.2g / 10min) (hereinafter referred to as EBR (1))

Base material layer (A2): 65 parts by mass of PP (2), 15 parts by mass of HMS-PP (1), 20 parts by mass of EBR (1)

    (Example 7)    

A laminated film was obtained in the same manner as in Example 1 except that the resin component of the resin mixture used in the base material layer (A1) and the base material layer (A2) was set to the following.

Base material layer (A1): 100 parts by mass of PP (1)

Base material layer (A2): 80 parts by mass of PP (2), 10 parts by mass of HMS-PP (1), and 10 parts by mass of EBR (1)

    (Comparative example 1)    

A laminated film was obtained in the same manner as in Example 1 except that the resin component of the resin mixture used in the base material layer (A1) and the base material layer (A2) was set to the following.

Base material layer (A1): 100 parts by mass of PP (1)

Base material layer (A2): 100 parts by mass of PP (2)

    (Comparative example 2)    

A laminated film was obtained in the same manner as in Example 1 except that the resin component of the resin mixture used in the base material layer (A1) and the base material layer (A2) was set to the following.

Base material layer (A1): 75 parts by mass of PP (1), 15 parts by mass of HMS-PP (2), 10 parts by mass of thermoplastic elastomer (2) (ethylene-butene copolymer: density 0.89 g / cm ³ , MFR 3.6g / 10min) (hereinafter referred to as EBR (2))

Base material layer (A2): 100 parts by mass of PP (2)

The films obtained in the above Examples and Comparative Examples were evaluated as follows. The results obtained are shown in the following table.

    [Opening evaluation]    

On the base layer (A) side of the obtained film, a biaxially stretched nylon film having a film thickness of 25 μm was laminated using a urethane-based adhesive to form a multilayer film. Using the obtained multi-layer film, a container with a capacity of 150 cm ³ having a crotch having a circular shape with a width of 5 mm and an outer diameter of 95 mmφ and a thickness of 600 μm was sealed with a packaging machine at a temperature of 180 ° C., a time of 1.0 second, and a load A heat-sealed sample was obtained at 160 kg. From this sample, the unsealing strength was measured using a push-pull gauge to evaluate the unsealing property.

◎: Unsealing strength is 20 (N) or less

○: Unsealing strength is 20 (N) or more and less than 25

×: Unsealing strength is 25 (N) or more

The number of persons who delaminated at the time of opening (the number of samples was 10) was also measured. The results are shown in Table 1.

    [Measurement of impact strength]    

After the films obtained in the examples and comparative examples were kept in a constant-temperature room at 0 ° C for 4 hours, a 1-inch diameter spherical metallic impact head was used to measure the impact strength by the film impact method.

As shown in the above table, Example 1 of 5 to 50% by mass of the resin component of the base material layer contains a propylene resin (HMS-PP (1), HMS-PP (2)) having a melt tension of 0.03 to 0.40N. The laminated film of the present invention of ~ 7 can be properly sealed even at a high sealing temperature, and has excellent openability. In addition, the laminated films of Examples 1 to 7 have excellent impact resistance of 0.3 (J) or more, and the laminated films of Examples 6 and 7 have particularly excellent impact strength of 0.4 (J) or more. Impact resistance. On the other hand, although the laminated films of Comparative Examples 1 and 2 can be sealed at a high temperature, a suitable unsealing property cannot be obtained.

Claims (9)

    An easy-opening laminated film, which is an easy-opening laminated film having a base material layer and a heat-sealing layer, is characterized in that the base material layer has an acrylic resin (a1 containing a melt tension of 230 ° C and a 0.03 to 0.40N tension) ), The content of the propylene resin (a1) is 5 to 50% by mass of the resin components contained in the base material layer.         For example, the easy-opening laminated film of claim 1, wherein the thickness ratio of the resin layer containing the propylene resin (a1) in the base material layer is 30% or more.         For example, the easy-opening laminated film of claim 1 or 2, wherein the base material layer contains a propylene resin (a2) having a melt flow rate (230 ° C, 21.18N) of 0.5 to 10 g / 10 minutes as the propylene resin (a1). For resins other than), the content of the propylene resin (a2) is 50% by mass or more of the resin component contained in the base material layer.         The easily-openable laminated film according to any one of claims 1 to 3, wherein the base material layer contains a thermoplastic elastomer (a3), and the content of the thermoplastic elastomer (a3) is equal to that of the resin component contained in the base material layer. 5 to 30% by mass.         The easy-opening laminated film according to any one of claims 1 to 4, wherein the heat-sealing layer is a layer having destructive agglutination.         The easy-opening laminated film according to any one of claims 1 to 5, wherein the heat-sealing layer contains an ethylene-based resin and a propylene-based resin.         For example, the easy-opening laminated film according to any one of claims 1 to 6, wherein the total thickness is 20 to 100 μm, the thickness ratio of the substrate layer is 70 to 95%, and the thickness ratio of the heat seal layer is 5 to 30%. .         The easy-opening laminated film according to any one of claims 1 to 7, which is used for sealing an opening portion of a packaging container having an opening portion.         An easy-opening multi-layer film, characterized in that an extended base film is laminated on the surface layer of the easy-opening multi-layer film according to any one of claims 1 to 8.