JPWO2019102856A1 - Easy-open laminated film, easy-open laminated film - Google Patents

Abstract

A base material layer and a heat seal layer, wherein the base material layer has a resin layer containing a propylene-based resin (a1) having a melt tension at 230 ° C. of 0.03 to 0.40 N; The flow of the resin component at a high temperature by the easy-opening laminate film in which the content of the resin (a1) is 5 to 50% by mass of the resin component contained in the base material layer and the easy-opening laminate film using the same. The heat sealing property and the easy-opening property can be simultaneously obtained even when sealing is performed at a high sealing temperature.

Description

  The present invention relates to an easily-openable laminated film that can be used for sealing an opening of a packaging container that can be suitably packaged and can be easily opened.

  2. Description of the Related Art Conventionally, packaging bodies that can be easily opened using easily-openable films have been widely used as packaging bodies for various foods and medical devices. As such a packaging form, for example, a package (see Patent Document 1) in which an easily openable film is formed into a bag shape having an opening, or an opening of a packaging container having an opening is an easily openable film. A package (see Patent Document 2) and the like sealed with is disclosed.

JP2015-120249A JP 2006-210063 A

  Films used in these packages need to be able to be opened easily when opened. However, in packages such as food and medical devices, if the package is opened due to impact during distribution, etc., the packaged material cannot be used. Therefore, an easy-open film that can be sealed at a high sealing temperature is demanded. Moreover, since the same problem also arises when breakage occurs due to impact during distribution, etc., there is a high demand for improvement in impact resistance.

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

  Furthermore, this invention makes it a subject to provide the easily openable film which has suitable impact resistance in addition to the said subject.

  The present invention is an easily openable laminated film having a base material layer and a heat seal layer, wherein the base material layer comprises a propylene-based resin (a1) having a melt tension at 230 ° C. of 0.03 to 0.40 N. The easy-open laminate film having the resin layer to be contained and the content of the propylene resin (a1) being 5 to 50% by mass in the resin component contained in the base material layer solves the above-mentioned problem. is there.

  The easy-open laminate film of the present invention contains an easy-open laminate film having a base material layer and a heat seal layer, and contains a propylene-based resin having a melt tension of 0.03 to 0.40 N in the base material layer. Thus, the fluidity of the resin component at a high temperature can be suitably suppressed, and it is possible to have both suitable heat sealability and easy opening even when sealed at a high sealing temperature.

  The easy-open laminate film of the present invention has a base material layer and a heat seal layer, and the base material layer contains a propylene-based resin (a1) having a melt tension at 230 ° C. of 0.03 to 0.40 N. It is an easy-open laminate film having a resin layer and containing 5 to 50% by mass of the propylene resin (a1) in the resin component contained in the base material layer.

[Base material layer]
The base material layer used for this invention contains propylene-type resin (a1) whose melt tension in 230 degreeC is 0.03-0.40N. The melt tension propylene resin (a1) has a structure in which a long chain branch is introduced into the main chain of the polypropylene resin, and has an increased melt tension. In the present invention, by using the propylene-based resin in the base material layer, it is possible to suppress the flow of the base material layer at the time of high-temperature sealing, to suppress an excessive increase in peel strength, and to realize suitable peelability. . The melt tension of the propylene-based resin (a1) is preferably 0.05 to 0.40 N, and more preferably 0.10 to 0.40 N.

  Content of propylene-type resin (a1) in a base material layer is 5-50 mass% in the resin component contained in a base material layer, Preferably it is 5-40 mass%, More preferably, it is 8-30 mass%. More preferably, it is 8 to 25% by mass. By setting the content of the propylene-based resin (a1) in this range, suitable peelability can be realized by suppressing the fluidity of the base material layer during high-temperature sealing.

  As the resin other than the propylene resin (a1) used for the base material layer, various resins used for the packaging film can be used, and among them, an olefin resin can be preferably used. As the olefin resin, a propylene resin other than the propylene resin or an ethylene resin can be used. Examples of the propylene resin include propylene homopolymers, copolymers of propylene and α-olefins such as ethylene and butene-1, and the copolymers include both random copolymers and block copolymers. Can be used. In addition, polyethylene resins such as very low density polyethylene (VLDPE), linear low density polyethylene (LLDPE), low density polyethylene (LDPE), linear medium density polyethylene (LMDPE), and medium density polyethylene (MDPE) are used as the ethylene resin. In addition, any of ethylene-vinyl acetate copolymer (EVA) can be used.

  When using olefin resin as resin other than the said propylene-type resin (a1), it is preferable that the content is 70-95 mass% in the resin component contained in a base material layer, and 80-95 mass % Is more preferable. By using an olefin-based resin other than the propylene-based resin (a1) in this range, it is easy to obtain suitable film formability.

  Of the above-mentioned resins other than the propylene-based resin (a1), it is preferable to use a propylene-based resin, and the melt flow rate (230 ° C., 21.18 N) is 0.5 to 10 g / 10 minutes, preferably 0. It is further preferable to use the propylene-based resin (a2) of 5 to 8 g / 10 minutes, more preferably 0.5 to 5 g / 10 minutes. By using the propylene-based resin (a2) in combination with the propylene-based resin (a1), the fluidity at the time of high-temperature sealing can be more suitably suppressed, and it becomes easy to have both excellent heat sealability and easy-openability. In addition, it becomes easy to adjust these heat-sealability and easy-openability especially suitably by using propylene-type block copolymer resin as propylene-type resin (a2).

  When the propylene-based resin (a2) is used, it is easy to obtain suitable heat sealability, easy opening property, film formability, and the like, so that the content is 50% by mass in the resin component contained in the base material layer. It is preferable to set it as the above, It is preferable that it is 70-95 mass%, and it is more preferable that it is 80-95 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. As the said thermoplastic elastomer (a3), a polyethylene-type elastomer, a polypropylene-type elastomer, a butene-type elastomer etc. can be used, for example. Especially, an ethylene-type elastomer can be used preferably, and especially the copolymer of ethylene and C3-C8 alpha olefin can be used preferably.

  When using a thermoplastic elastomer (a3), it is preferable to make the content into 5-30 mass% in the resin component contained in a base material layer, and it is more preferable to set it as 10-20 mass%. Use of the thermoplastic elastomer (a3) within the above range makes it easy to achieve suitable impact resistance.

  In the base material layer used in the present invention, a resin other than the olefin resin and the thermoplastic elastomer may be used in combination. Examples of the other resin include ethylene-methyl methacrylate copolymer (EMMA), ethylene-ethyl acrylate copolymer (EEA), ethylene-methyl acrylate (EMA) copolymer, ethylene-ethyl acrylate-anhydrous maleic acid. Ethylene copolymers such as acid copolymers (E-EA-MAH), ethylene-acrylic acid copolymers (EAA), ethylene-methacrylic acid copolymers (EMAA); and ethylene-acrylic acid copolymers These ionomers and ethylene-methacrylic acid copolymer ionomers can be used.

  When using the other resin, the content is preferably 30% by mass or less, more preferably 20% by mass or less, and more preferably 10% by mass in the resin component contained in the base material layer. % Or less is more preferable.

  In the base material layer, various additives and the like may be appropriately used in addition to the resin component. As additives, for example, colorants such as lubricants, antiblocking agents, ultraviolet absorbers, light stabilizers, antistatic agents, antifogging agents, and the like can be used as appropriate. When using these additives, it is preferably used in an amount of 2 parts by mass or less, more preferably about 0.01 to 1 part by mass with respect to 100 parts by mass of the resin component used in the base material layer.

[Heat seal layer]
As the heat seal layer used in the present invention, various heat seal layers used for packaging films can be appropriately used. The opening form of the easy-open laminated film of the present invention is not particularly limited, such as due to delamination between the base material layer and the heat seal layer, or due to cohesive failure of the heat seal layer. It is preferable to use a layer having cohesive failure because it can cope with various shapes of containers.

  The heat seal layer used in the present invention preferably uses an olefin-based resin as a main resin component because it is easy to obtain adhesion with the base material layer. As the olefin resin, the propylene resin or ethylene resin can be preferably used.

  As the propylene-based resin or ethylene-based resin used for the heat seal layer, the propylene-based resin or ethylene-based resin exemplified in the base material layer can be appropriately used. Especially, as a propylene-type resin, a propylene-ethylene random copolymer and a propylene-ethylene-butene-1 random copolymer are preferable. As the ethylene resin, high density polyethylene (HDPE), linear low density polyethylene (LLDPE), low density polyethylene (LDPE), or the like can be preferably used.

Among ethylene 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.

  Resin contained in the heat seal layer because the content of the olefin resin in the heat seal layer has good oil resistance, there is no decrease in seal strength due to heat sterilization of food packaging containing oil, and it is difficult to cause bag breakage. It is preferably 90% by mass or more, more preferably 95% by mass in the components.

  As a heat seal layer used in the present invention, it is preferable to use a propylene resin and an ethylene resin in combination among the olefin resins. By using these resins in combination, it becomes easy to realize suitable opening properties due to cohesive failure of the heat seal layer.

  When a polypropylene resin and an ethylene resin are used in combination, a propylene resin having a melt flow rate (230 ° C., 21.18 N) of preferably 2 to 15 g / 10 min, more preferably 4 to 10, and a melt flow The rate (190 ° C., 21.18 N) is preferably 2 to 25 g / 10 min, more preferably 5 to 20 g / 10 min. Each content is preferably 30 to 70% by mass of the propylene-based resin and 30 to 70% by mass of the ethylene-based resin, 40 to 60% by mass of the propylene-based resin, and 40 to 60% by mass of the ethylene-based resin. More preferably.

  The heat seal layer may contain the polypropylene resin (a1), but the content is preferably 30% or less, and more preferably 20% or less.

  When a resin other than the olefin resin is used as the resin component in the heat seal layer, ethylene-methyl methacrylate copolymer (EMMA), ethylene-ethyl acrylate copolymer (EEA), ethylene-methyl Acrylate (EMA) copolymer, ethylene-ethyl acrylate-maleic anhydride copolymer (E-EA-MAH), ethylene-acrylic acid copolymer (EAA), ethylene-methacrylic acid copolymer (EMAA), etc. An ethylene copolymer; an ionomer of an ethylene-acrylic acid copolymer, an ionomer of an ethylene-methacrylic acid copolymer, and the like can be used.

  When using other resins than the olefin resin, the content is preferably 20% by mass or less in the resin component contained in the heat seal layer, and 10% by mass or less. More preferred.

  In the heat seal layer, various additives may be appropriately used in addition to the resin component. As additives, for example, colorants such as lubricants, antiblocking agents, ultraviolet absorbers, light stabilizers, antistatic agents, antifogging agents, and the like can be used as appropriate. When using these additives, it is preferably used in an amount of 2 parts by mass or less, more preferably about 0.01 to 1 part by mass with respect to 100 parts by mass of the resin component used in the heat seal layer.

[Easily openable laminated film]
The easy-open laminated film of the present invention is a film in which the base material layer and the heat seal layer are laminated. The easy-open film of the said structure can have suitable heat-sealing property and easy-open property also at the time of high temperature sealing as above-mentioned.

  The easy-open laminated film of the present invention preferably has a total thickness of 20 to 100 μm, and more preferably 20 to 60 μm. By setting the thickness, suitable heat sealability can be realized.

  In the easily openable laminated film of the present invention, the thickness ratio of the base material layer to the total thickness of the film is preferably 70 to 95%, and more preferably 80 to 95%. Moreover, it is preferable that the thickness ratio of a heat seal layer is 5 to 30%, and it is more preferable that it is 5 to 20%. It becomes easy to obtain suitable openability by setting it as the said thickness ratio.

  Moreover, in the easily openable laminated film of this invention, even if the base material layer is a structure which consists of a single layer, it may be formed from multiple layers. Even when the base material layer is composed of two or more layers, it is preferable that the content of the propylene-based resin (a1) in the base material layer is 5 to 50% by mass in the resin component contained in the base material layer. Heat sealability and easy openability can be realized.

  The easy-open laminated film of the present invention is a so-called sealant film used in various packaging applications, and is a film having a structure in which a heat seal layer and a base material layer are laminated. The base material layer in the said structure means the layer laminated | stacked on a heat seal layer, and when providing the below-mentioned laminate base material on a base material layer and using it as a laminate film, a heat seal layer and a laminate base material are used. It becomes a layer between the adhesive layers to be bonded. As the base material layer, various functional layers may be included in addition to the above-described layer containing an olefin resin as a main component. However, a configuration comprising a layer containing an olefin resin as a main component can be preferably used.

  When the base material layer has a plurality of layers, all layers constituting the base material layer may be a resin layer containing the propylene-based resin (a1) (hereinafter sometimes referred to as a layer (A1)). A layer containing the resin (a1) and a layer not containing the propylene resin (a1) (hereinafter sometimes referred to as layer (A2)) may be laminated.

  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-based resin (a1) in the base material layer is preferably 30% or more, more preferably 40 to 100%, and more preferably 50 to 100%. Particularly preferred. By setting the thickness ratio of the resin layer containing the propylene-based resin (a1) within the above range, it is easy to obtain suitable openability.

  On the other hand, the average content of the propylene-based resin (a1) in the resin component contained in the layer containing the propylene-based resin (a1), such as when the resin component is provided with a layer composed only of the propylene-based resin (a1), is 50 mass. When it exceeds%, the total thickness ratio of the resin layer containing the propylene-based resin (a1) in the base material layer is preferably less than 30%, more preferably 5 to 20%, It is preferably 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 appropriately used depending on the application. Especially, the resin layer which uses an olefin resin as the main resin component can be preferably used since it is easy to ensure interlayer adhesion with the layer (A1) or the like. As an example of such a layer (A2), the resin layer etc. which use 1 type or 2 types of said resin (a1)-(a3) can be illustrated preferably.

  Examples of the layer structure in the case where the base material layer is a plurality of layers include a structure in which two or three layers (A1) are laminated, layer (A1) / layer (A2), layer (A1) / layer (A2) / Examples of the structure include layer (A1), layer (A2) / layer (A1) / layer (A2), and the like.

  The easy-open laminated film of the present invention is preferably 20% or less, more preferably 15% or less, and even more preferably 10% or less, because the contents packaged by the haze are easily visible. preferable.

[Manufacturing method of easy-open laminated film]
Although it does not specifically limit as a manufacturing method of the easily openable laminated film of this invention, For example, each resin or resin mixture used for each layer is heat-melted with a separate extruder, respectively, a co-extrusion multilayer die method and a feed block method For example, the heat-seal layer / intermediate layer / surface layer may be laminated in a molten state by a method such as the above, and then co-extruded to form a film by inflation, T-die / chill roll method, or the like. The co-extrusion method is preferable because the thickness ratio of each layer can be adjusted relatively freely, and a laminated film having excellent hygiene and cost performance can be obtained. When a resin having a large difference between the melting point and Tg is laminated, the appearance of the film may be deteriorated during coextrusion, or it may be difficult to form a uniform layer structure. In order to suppress such deterioration, a T-die / chill roll method that can perform melt extrusion at a relatively high temperature is preferable.

  Further, when printing or the like is performed on the surface of the base material layer, it is preferable to perform a surface treatment on the base material layer in order to improve adhesiveness with the printing ink. Examples of such surface treatment include corona treatment, plasma treatment, chromic acid treatment, flame treatment, hot air treatment, surface oxidation treatment such as ozone / ultraviolet treatment, and surface unevenness treatment such as sandblasting. Corona treatment is preferable.

[Laminate film]
The laminate film of the present invention is a film in which a laminate substrate is laminated on the substrate layer of the easy-open laminate film. The laminate base material is not particularly limited, but is generally a stretched base film because it ensures strength that does not break, ensures heat resistance during heat sealing, and improves printing design. It is preferable. As the stretched base film, a biaxially stretched polyester film, a biaxially stretched nylon film, a biaxially stretched polypropylene film, etc. can be used. Is more preferable. In addition, as said base film, an easy tear process and an antistatic process may be performed as needed.

  Although it does not specifically limit as a manufacturing method of the laminate film of this invention, For example, the method of laminating a laminate base material on the base material layer of the said laminated | multilayer film is mentioned. Examples of the method for laminating the laminate base material on the laminated film of the present invention include a dry laminating method, a thermal laminating method, a multilayer extrusion coating method, and the like. Among these, the dry laminating method is more preferable. Examples of the adhesive used when laminating the laminated film and the laminate base material by a dry laminating method include a polyether-polyurethane adhesive and a polyester-polyurethane adhesive. Moreover, it is preferable to apply a corona discharge treatment to the surface of the surface layer before laminating the coextruded laminated film of the present invention and the substrate, because the adhesion with the substrate is improved.

[Packaging]
The easy-open laminate film and laminate film of the present invention can be suitably used as various packaging materials. In particular, it can be suitably used for jelly, tofu and cooked rice containers.

  The polyolefin resin used for the packaging container is preferably polypropylene, for example, propylene such as homopolypropylene, propylene-ethylene copolymer, propylene-butene-1 copolymer, propylene-ethylene-butene-1 copolymer. A homopolymer or a copolymer of propylene and an α-olefin may be mentioned. Among these polypropylene resins, it is preferable that the propylene monomer unit content in the polymer is 70 mol% or more because sufficient sealing strength can be obtained.

  The heat seal surface of the opening of the packaging container preferably contains a polyolefin resin in a proportion of 60% by mass or more, more preferably 80% by mass or more. If the content of the polyolefin-based resin on the heat seal surface is in the above range, it is preferable because particularly suitable seal strength is easily obtained. The resin that may be used in combination with the polyolefin resin on the heat seal surface is not particularly limited as long as it is a resin that is compatible with polypropylene resin and does not inhibit heat seal. Examples thereof include polyethylene resins such as polymers and ethylene-α-olefin copolymers.

  Moreover, as resin other than the above, a packaging container using polyethylene terephthalate or polystyrene in the opening can be preferably used.

  The present invention will be described in more detail with reference to examples and comparative examples. Hereinafter, unless otherwise specified, “part” and “%” are based on mass.

(Example 1)
The resin mixture which forms each layer was prepared using the following resin as a resin component which forms each layer of a base material layer (A) and a heat seal layer (B), respectively. In addition, the base material layer (A) was made into 2 layer structure of a base material layer (A1) and a base material layer (A2). The resin mixture forming each layer is supplied to each of three extruders, and the average thickness of each layer of the laminated film formed by the base layer (A1) / base layer (A2) / sealing layer (B) is The film was coextruded from a T die at an extrusion temperature of 270 ° C. so as to be 15 μm / 30 μm / 5 μm, and cooled with a 40 ° C. water-cooled metal cooling roll to form a laminated film having a total thickness of 50 μm. Next, a corona discharge treatment was applied to the surface of the base material layer (A1) of the obtained laminated film so that the wetting tension was 44 mN / m to obtain a laminated film.
Base material layer (A1): Propylene copolymer (1) (density 0.90 g / cm ³ , MFR 3.0 g / 10 min) (hereinafter referred to as PP (1)) 90 parts by mass, high melt tension polypropylene (1) A mixture with 10 parts by mass (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): Propylene copolymer (2) (density 0.90 g / cm ³ , MFR 2.0 g / 10 min) (PP (2)) 90 parts by mass and HMS-PP (1) 10 parts by mass Mixture with.
Heat seal layer (B): Propylene-ethylene copolymer (1) (density 0.90 g / cm ³ , MFR 7.0 g / 10 min) (hereinafter referred to as COPP (1)) 50 parts by mass, high-density polyethylene (Density 0.96 g / cm ³ , MFR 8.0 g / 10 min) (HDPE (1)) A mixture with 50 parts by mass.

(Example 2)
A laminated film was obtained in the same manner as in Example 1 except that the resin components of the resin mixture used for the base material layer (A1) and the base material layer (A2) were as follows.
Base material layer (A1): PP (1) 80 parts by mass, HMS-PP (1) 20 parts by mass Base material layer (A2): PP (2) 80 parts by mass, HMS-PP (1) 20 parts by mass

(Example 3)
A laminated film was obtained in the same manner as in Example 1 except that the resin components of the resin mixture used for the base material layer (A1) and the base material layer (A2) were as follows.
Base material layer (A1): PP (1) 80 parts by mass, high melt tension polypropylene (2) (density 0.91 g / cm ³ , MFR 2.5 g / 10 min, melt tension 0.15 N) (hereinafter, HMS-PP ( 2)) 20 parts by mass Base material layer (A2): PP (2) 80 parts by mass, HMS-PP (2) 20 parts by mass

(Example 4)
A laminated film was obtained in the same manner as in Example 1 except that the resin components of the resin mixture used for the base material layer (A1) and the base material layer (A2) were as follows.
Base material layer (A1): 80 parts by mass of PP (1), high melt tension polypropylene (3) (density 0.91 g / cm ³ , MFR 9.0 g / 10 min, melt tension 0.05 N) (hereinafter, HMS-PP ( 3). 20 parts by mass Base material layer (A2): PP (2) 80 parts by mass, HMS-PP (3) 20 parts by mass

(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 for the heat seal layer (B) was as follows.
Heat seal layer (B): propylene-ethylene copolymer (2) (density 0.90 g / cm ³ , MFR 10.0 g / 10 min) (hereinafter referred to as COPP (2)) 60 parts by mass, HDPE (1) 40 parts by mass

(Example 6)
A laminated film was obtained in the same manner as in Example 1 except that the resin components of the resin mixture used for the base material layer (A1) and the base material layer (A2) were as follows.
Base material layer (A1): PP (1) 65 parts by mass, HMS-PP (1) 15 parts by mass, thermoplastic elastomer (1) (ethylene-butene copolymer: density 0.89 g / cm ³ , MFR 1.2 g / 10 min) (hereinafter referred to as EBR (1)) 20 parts by mass Base layer (A2): PP (2) 65 parts by mass, HMS-PP (1) 15 parts by mass, EBR (1) 20 parts by mass

(Example 7)
A laminated film was obtained in the same manner as in Example 1 except that the resin components of the resin mixture used for the base material layer (A1) and the base material layer (A2) were as follows.
Base material layer (A1): PP (1) 100 parts by weight Base material layer (A2): PP (2) 80 parts by weight, HMS-PP (1) 10 parts by weight, EBR (1) 10 parts by weight

(Comparative Example 1)
A laminated film was obtained in the same manner as in Example 1 except that the resin components of the resin mixture used for the base material layer (A1) and the base material layer (A2) were as follows.
Base material layer (A1): PP (1) 100 parts by weight Base material layer (A2): PP (2) 100 parts by weight

(Comparative Example 2)
A laminated film was obtained in the same manner as in Example 1 except that the resin components of the resin mixture used for the base material layer (A1) and the base material layer (A2) were as follows.
Base material layer (A1): PP (1) 75 parts by mass, HMS-PP (2) 15 parts by mass, thermoplastic elastomer (2) (ethylene-butene copolymer: density 0.89 g / cm ³ , MFR 3.6 g) / 10 min) (hereinafter referred to as EBR (2)) 10 parts by mass Base material layer (A2): PP (2) 100 parts by mass

  The following evaluation was performed about the film obtained by the said Example and comparative example. The results obtained are as shown in the table below.

[Evaluation of openability]
A laminate film was prepared by laminating a 25 μm thick biaxially stretched nylon film using a urethane adhesive on the base layer (A) side of the obtained film. The obtained laminate film was sealed with a packaging machine using a circular container having a width of 5 mm, an outer diameter of 95 mmφ and a thickness of 600 μm, and a capacity of 150 cm ³ , and the temperature was 180 ° C. for 1.0 second. A heat seal sample was obtained under a load of 160 kg. The unsealing property was evaluated by measuring the unsealing strength from this sample using a push-pull gauge.
◎: Opening strength is 20 (N) or less ○: Opening strength is 20 (N) or more and less than 25 ×: Opening strength is 25 (N) or more In addition, the number of samples with delamination when opening (number of samples: 10) It was measured. The results are shown in Table 1.

[Measurement of impact strength]
After the films obtained in Examples and Comparative Examples were held in a temperature-controlled room adjusted to 0 ° C. for 4 hours, the impact strength by the film impact method was measured using a spherical metallic impact head having a diameter of 1 inch. did.

  As is clear from the above table, 5-50% by mass of the propylene-based resin (HMS-PP (1), HMS-PP (2)) having a melt tension of 0.03 to 0.40 N in the resin component of the base material layer. The laminated films of the present invention of Examples 1 to 7 that were contained were able to be suitably sealed even at a high sealing temperature, and had excellent openability. In addition, the laminated films of Examples 1 to 7 have excellent impact resistance with an impact strength of 0.3 (J) or more, and among them, the laminated films of Examples 6 and 7 have an impact strength of 0.00. It had a particularly excellent impact resistance of 4 (J) or more. On the other hand, although the laminated film of Comparative Examples 1 and 2 can be sealed at a high temperature, a suitable opening property cannot be obtained.

Claims (9)

An easy-open laminated film having a base material layer and a heat seal layer,
The base material layer has a resin layer containing a propylene-based resin (a1) having a melt tension at 230 ° C. of 0.03 to 0.40 N;
Content of the said propylene-type resin (a1) is 5-50 mass% in the resin component contained in a base material layer, The easily openable laminated film characterized by the above-mentioned.   The easily openable laminated film according to claim 1, wherein the thickness ratio of the resin layer containing the propylene-based resin (a1) in the base material layer is 30% or more.   The base material layer contains a propylene resin (a2) having a melt flow rate (230 ° C., 21.18 N) of 0.5 to 10 g / 10 min as a resin other than the propylene resin (a1), The easily openable laminated film according to claim 1 or 2, wherein the content of the propylene-based resin (a2) is 50% by mass or more in the resin component contained in the base material layer.   The base material layer contains a thermoplastic elastomer (a3), and the content of the thermoplastic elastomer (a3) is 5 to 30% by mass in the resin component contained in the base material layer. The easy-open laminated film as described.   The easily openable laminated film according to any one of claims 1 to 4, wherein the heat seal layer is a layer having cohesive failure.   The easily openable laminated film according to any one of claims 1 to 5, wherein the heat seal layer contains an ethylene resin and a propylene resin.   The total thickness is 20 to 100 µm, the thickness ratio of the base material layer is 70 to 95%, and the thickness ratio of the heat seal layer is 5 to 30%. Laminated film.   The easily openable laminated film according to any one of claims 1 to 7, which is used for sealing an opening of a packaging container having an opening.   A stretchable base film is laminated on the surface layer of the easy-open laminate film according to any one of claims 1 to 8, wherein the easy-open laminate film.