WO2017018284A1

WO2017018284A1 - Multilayer film and packaging material

Info

Publication number: WO2017018284A1
Application number: PCT/JP2016/071218
Authority: WO
Inventors: 一範小橋; 松原　弘明; 渡辺　康史
Original assignee: Dic株式会社
Priority date: 2015-07-24
Filing date: 2016-07-20
Publication date: 2017-02-02
Also published as: TWI686302B; JPWO2017018284A1; TW201710092A; JP6103334B1

Abstract

The present invention relates to a multilayer film which is used for packaging materials for packaging food, sundry goods, magazines and the like, and enables the achievement of excellent print adhesion that makes omission of print less likely even if in contact with a resin sheet such as a vinyl chloride sheet, while maintaining preferable fusing strength, by introducing styrene from a styrene elastomer into a print layer, which contains a propylene resin, of a multilayer film that has the print layer. In addition, compatibility with a propylene resin is improved and suitable transparency is able to be achieved by using a styrene elastomer, and excellent impact resistance is also able to be achieved.

Description

Laminated film and packaging material

The present invention relates to a laminated film used for a packaging material for packaging foods, miscellaneous goods, magazines, and the like, and a packaging material comprising the film.

Conventionally, a laminated film in which a plurality of resins are laminated is used as a packaging film used for packaging bread and other foods. As such a packaging film, a laminated film using an olefin resin is widely used because it is easy to obtain heat sealability and the like. (For example, see Patent Documents 1 and 2).

Laminated films used for various types of packaging are often printed on the surface layer for the purpose of display, content display, design, etc., but if the adhesion of the printing is low, printing will drop out The adhesion of printing is improved by surface treatment such as corona treatment.

JP 2002-210897 A JP 2007-152730 A

However, in the conventional laminated film, when the printed layer comes into contact with the surface of a resin sheet such as polyvinyl chloride, the printing may be transferred to the resin sheet and the printing may fall off, so further improvement in printing adhesion is required. It has been. On the other hand, if surface treatment such as corona treatment is performed in order to improve the printing adhesiveness of the surface layer of the laminated film, although the printing adhesiveness is improved, the fusing strength is reduced when the film is melted and adhered. Further, it was difficult to further improve the printing adhesion by the surface treatment.

The problem to be solved by the present invention is to provide a laminated film capable of realizing excellent printing adhesion while having a suitable fusing strength.

Furthermore, an object of the present invention is to provide a laminated film having suitable transparency and excellent impact resistance in addition to the above problems.

The present invention is a laminated film in which one surface layer is a printing layer and the other surface layer is a sealing layer, the printing layer contains a propylene resin and a styrene elastomer, and the styrene content in the printing layer is 2 The above-mentioned problem is solved by a laminated film of ˜15% by mass.

In the present invention, by introducing styrene with a styrene-based elastomer into the printed layer of the laminated film having a printed layer containing a propylene-based resin, the resin sheet such as vinyl chloride is brought into contact while maintaining a suitable fusing strength. In this case, it is possible to realize excellent printing adhesion that is less likely to cause printing loss. Moreover, by using a styrene-based elastomer, compatibility with the propylene-based resin is improved, suitable transparency can be realized, and excellent impact resistance can be realized.

In the laminated film of the present invention, one surface layer is a printing layer on which various printing is performed, and the other surface layer is a sealing layer, the printing layer contains a propylene-based resin and a styrene-based elastomer, and contains styrene in the printing layer. A laminated film having an amount of 2 to 15% by mass.

[Print layer]
The printing layer used for the laminated film of the present invention contains a propylene resin and a styrene elastomer. As the propylene-based resin, propylene-based resins used for packaging films can be suitably used. For example, propylene homopolymer, propylene-α-olefin copolymer, such as propylene-ethylene copolymer, propylene-butene- 1 copolymer, propylene-ethylene-butene-1 copolymer, metallocene catalyst-based polypropylene and the like. These may be used alone or in combination.

In particular, when the laminated film is a transparent laminated film, it is preferable to use a propylene-ethylene random copolymer as the resin component because it is easy to obtain suitable transparency and adhesion to the intermediate layer. When using a propylene-ethylene random copolymer, the ratio of the propylene-ethylene random copolymer in the propylene-based resin contained in the printing layer is preferably 60% by mass or more, and 70% by mass or more. It is more preferable. It is also preferable to use substantially only a propylene-ethylene random copolymer as the propylene resin.

As the propylene-ethylene random copolymer, the ethylene content is preferably 10% by mass or less, more preferably 8% by mass or less, because it is easy to obtain suitable blocking resistance. More preferably it is. Moreover, since it is easy to obtain suitable impact resistance, the ethylene content is preferably 2% by mass or more, more preferably 3% by mass or more, and further preferably 4% by mass or more.

Further, the melt flow rate (MFR) of the propylene-ethylene random copolymer is not particularly limited as long as it is within a range in which a laminated film can be formed. However, since it is easy to obtain good moldability, it is 0.5 g / 10 min or more. It is preferably 3 g / 10 minutes or more, more preferably 5 g / 10 minutes or more. Moreover, since it is easy to obtain suitable impact resistance, MFR is preferably 20 g / 10 min or less, more preferably 15 g / 10 min or less, and more preferably 12 g / 10 min or less.

Propylene - density of the ethylene random copolymer, is preferably 0.88 g / cm ³ or more, and more preferably 0.89 g / cm ³ or more.

The melting point of the propylene-ethylene random copolymer is preferably 110 ° C. or more, and more preferably 115 ° C. or more, from the viewpoint of deterioration in bag-making suitability due to a decrease in rigidity and slipperiness. Moreover, it is preferable that it is 150 degrees C or less, and it is more preferable that it is 145 degrees C or less from the surface of the tearability at the time of a low temperature, or the bag breaking.

The content of the propylene-based resin in the printing layer is preferably 60% by mass or more, and more preferably 65% by mass or more in the resin component contained in the printing layer. The content is preferably 95% by mass or less, and more preferably 90% by mass or less.

In this invention, since it is easy to implement | achieve suitable transparency of a laminated | multilayer film, it is preferable to make content of the block copolymer in a resin component into 10 mass% or less, and it is more preferable to set it as 5 mass% or more. In particular, it is particularly preferable not to contain it. The laminated film of the present invention can realize a particularly suitable effect when using a printing layer having a small block copolymer content.

The styrene-based elastomer used for the printing layer includes a copolymer having a styrene-based polymer block and a styrene-based random copolymer block obtained by hydrogenating a double bond portion of a random copolymer of styrene and a conjugated diene compound. Compound (A-1), general formula aba, or ab (a is a styrenic polymer block, b is a conjugated diene polymer block or a double bond in the conjugated diene polymer is hydrogenated) Styrenic block copolymer (A-2) represented by olefin polymer block obtained by addition). These styrenic elastomers containing a block part obtained by hydrogenating the double bond part of the conjugated diene part have excellent compatibility with the propylene resin, so that particularly suitable transparency is easily obtained.

Examples of the conjugated diene compound used as a raw material for the copolymer (A-1) or (A-2) include 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-pentadiene, and 2-methyl. -1,3-pentadiene, 1,3-hexadiene, 4,5-diethyl-1,3-octadiene, 3-butyl-1,3-octadiene, chloroprene, etc., from the viewpoint of industrial availability, 1,3-butadiene and isoprene are preferably used. Examples of the styrene compound forming the styrene polymer block include styrene, α-methyl styrene, P-methyl styrene, t-butyl styrene, divinyl benzene, 1.1-diphenyl styrene, N, N-dimethyl. -P-aminomethylstyrene N, N-diethyl-P-aminoethylstyrene and the like can be mentioned, and styrene is preferably used.

Examples of commercially available products include “Dynalon 1320P, Dynalon 2320P” manufactured by JSR Corporation, which is a hydrogenated product of styrene-butadiene random copolymer (hereinafter abbreviated as HSBR) as copolymer (A-1). Also, as styrene block copolymer (A-2), “SIS5200” manufactured by JSR Corporation, which is a styrene-isoprene-styrene block copolymer (hereinafter abbreviated as SIS), styrene-ethylene-butylene. A styrene block copolymer (hereinafter abbreviated as SEBS) “Dynalon 8600P, Dynalon 8903P” manufactured by JSR Corporation, a styrene-ethylene-propylene-styrene block copolymer (hereinafter abbreviated as SEPS). A Kuraray Co., Ltd. “Septon 2063, Septon 2004” Etc.

In the present invention, in order to increase the adhesion of printing, the styrene content with respect to the resin component in the printed layer is preferably 2% by mass or more, more preferably 2.5% by mass or more, and more preferably 3% by mass. More preferably, the above is used. Moreover, in order to suppress the fall of transparency, it is preferable that the styrene content in a printing layer shall be 15 mass% or less, and it is more preferable to set it as 13 mass% or less.

The content of the styrenic elastomer in the printed layer may be adjusted as appropriate so that the styrene content falls within the above range, but in order to suppress a decrease in rigidity, it is 40% by mass or less in the resin component contained in the printed layer. It is preferable that the content is 30% by mass or less. Moreover, although a minimum in particular is not restrict | limited, It is preferable to set it as 5 mass% or more, and it is more preferable to set it as 10 mass% or more.

In the printing layer, a resin other than the propylene resin and the styrene elastomer may be appropriately used in combination. Examples of the other resins include olefin resins other than those described above, for example, polyethylene resins such as very low density polyethylene (VLDPE), linear low density polyethylene (LLDPE), and low density polyethylene (LDPE), and ethylene-vinyl acetate copolymer. Polymer (EVA), ethylene-methyl methacrylate copolymer (EMMA), ethylene-ethyl acrylate copolymer (EEA), ethylene-methyl acrylate (EMA) copolymer, ethylene-ethyl acrylate-maleic anhydride copolymer An ethylene copolymer such as a polymer (E-EA-MAH), an ethylene-acrylic acid copolymer (EAA), an ethylene-methacrylic acid copolymer (EMAA); and an ionomer of an ethylene-acrylic acid copolymer; An ionomer of an ethylene-methacrylic acid copolymer can be used.

When the other resin is used in the printing layer, it is preferably 30% by mass or less, more preferably 20% by mass or less in the resin component.

In the printing layer, as components other than the above resin components, antifogging agents, antistatic agents, heat stabilizers, nucleating agents, antioxidants, lubricants, antiblocking agents, mold release agents, ultraviolet absorbers, etc. These components may be appropriately added as long as the object of the present invention is not impaired.

The surface of the printing layer is preferably treated so that the surface wetting tension is 38 mN / m or less, and more preferably 35 mN / m or less. When the wetting tension is in this range, the printing adhesion can be improved without causing a significant decrease in the fusing strength. Examples of the surface treatment method include corona discharge 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 discharge treatment is preferred. Further, the lower limit of the wetting tension is not particularly limited, but is preferably 30 mN / m or more.

[Seal layer]
The sealing layer used for this invention is a layer used for adhesion | attachment of the sealing layers of laminated | multilayer film, and adhesion | attachment of laminated | multilayer film, another container, a film, etc. What is necessary is just to select suitably the resin seed | species from which the suitable sealing strength is obtained for the said sealing layer according to a use aspect or to-be-sealed object. For example, when the sealing layers are sealed and used as a packaging bag, propylene such as propylene-ethylene (random) copolymer, propylene-1-butene copolymer, etc. from the point of obtaining an appropriate seal strength. A seal layer containing an α-olefin copolymer can be suitably used, and a seal layer containing a 1-butene-propylene copolymer is particularly preferable.

When 1-butene-propylene copolymer is used, the seal layer may be a seal layer made of 1-butene-propylene copolymer, but it is included in the seal layer because it is easy to suppress tearing. The content of the 1-butene-propylene copolymer in the resin component to be obtained is preferably 55% by mass or less, more preferably 50% by mass or less, and further preferably 45% by mass or less. Moreover, since it is easy to obtain suitable low temperature sealing properties, the propylene content is preferably 2 mol% or more, more preferably 3 mol% or more, and further preferably 5 mol% or more.

Further, when a 1-butene-propylene copolymer is used, the content is preferably 10% by mass or more, and more preferably 15% by mass or more. When the content of the 1-butene-propylene copolymer is within this range, it is easy to obtain suitable low-temperature sealability and tear resistance, and it is advantageous for cost reduction.

As the resin used in combination with the 1-butene-propylene copolymer, other polyolefin resins can be used as appropriate. However, since the seal strength is easily adjusted, propylene other than the 1-butene-propylene copolymer can be used. An α-olefin copolymer and an ethylene-α-olefin copolymer can be preferably used.

The α-olefin content in the 1-butene-propylene copolymer or ethylene-α-olefin copolymer is not particularly limited, but is preferably 1 to 20% by mass, and preferably 1.5 to 15% by mass. More preferred. Examples of the α-olefin include ethylene, propylene, 1-butene, 1-hexene, 4-methyl-1-pentene, 1-octene and the like. Of these, propylene-ethylene random copolymers as exemplified in the intermediate layer can be preferably used. The MFR is preferably from 0.5 to 20 g / 10 minutes, more preferably from 2 to 10 g / 10 minutes, since good moldability is easily obtained.

When 1-butene-propylene copolymer is contained, it is easy to adjust the heat seal temperature and strength at the time of easy opening seal at low temperature, the heat seal temperature range is wide, and appropriate heat seal strength as an easy opening seal Is easily obtained. Resin obtained by using 1-butene-propylene copolymer and propylene copolymer together at a weight ratio of 20/80 to 50/50 in order to obtain easy opening strength of 2 to 6 N / 15 mm The 1-butene-propylene copolymer used here is particularly preferably one having a 1-butene-derived component content of 60 to 95 mol%.

In the seal layer, other components than the above resin components include antifogging agents, antistatic agents, heat stabilizers, nucleating agents, antioxidants, lubricants, antiblocking agents, mold release agents, ultraviolet absorbers, etc. These components may be appropriately added as long as the object of the present invention is not impaired.

[Middle layer]
In the laminated film of the present invention, it is also preferable to appropriately provide an intermediate layer between the print layer and the seal layer. As the intermediate layer, an olefin resin can be preferably used.

Examples of the olefin resin used in the intermediate layer include propylene-α-olefin copolymers (propylene-butene-1 copolymer, propylene-ethylene-butene-1 copolymer, metallocene catalyst-based polypropylene, etc.), propylene Homopolymer, polyethylene resin such as very low density polyethylene (VLDPE), linear low density polyethylene (LLDPE), low density polyethylene (LDPE), ethylene-vinyl acetate copolymer (EVA), ethylene-methyl methacrylate copolymer Polymer (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-meta Ethylene copolymers such as acrylic acid copolymer (EMAA); more ethylene - ionomer of acrylic acid copolymer, ethylene - the ionomers of methacrylic acid copolymer can be used. These may be used alone or in combination.

Among these, from the viewpoint of adhesion to the printing layer and the seal layer, a propylene resin used for the printing layer can be preferably used. For example, a propylene homopolymer, a propylene-α-olefin copolymer such as propylene- An ethylene copolymer, a propylene-butene-1 copolymer, a propylene-ethylene-butene-1 copolymer, a metallocene catalyst-based polypropylene and the like can be preferably used. These may be used alone or in combination.

Further, if necessary, one or more of propylene-based resins are contained as a main component, preferably 75% by mass or more, and it is very low density polyethylene (VLDPE), linear low density polyethylene (LLDPE), low density. Polyethylene resin such as polyethylene (LDPE), ethylene-vinyl acetate copolymer (EVA), ethylene-methyl methacrylate copolymer (EMMA), ethylene-ethyl acrylate copolymer (EEA), ethylene-methyl acrylate (EMA) ) Copolymers, ethylene-ethyl acrylate-maleic anhydride copolymer (E-EA-MAH), ethylene-acrylic acid copolymer (EAA), ethylene-methacrylic acid copolymer (EMAA), etc. Polymer; further ethylene-acrylic acid copolymer ionomer, ethylene-meta Ionomers of acrylic acid copolymer may be mixed.

In the intermediate layer, as components other than the above resin components, antifogging agents, antistatic agents, heat stabilizers, nucleating agents, antioxidants, lubricants, antiblocking agents, mold release agents, UV absorbers, etc. These components may be appropriately added as long as the object of the present invention is not impaired.

[Laminated film]
The laminated film of the present invention is a laminated film having at least the above-mentioned print layer, intermediate layer and seal layer, and one surface layer of the laminate film is a print layer and the other surface layer is a laminate film comprising a seal layer. The laminated film having such a configuration can realize suitable tear resistance that is difficult to tear when enclosing contents while having good packaging suitability. Moreover, it is easy to realize good fusing seal strength, impact resistance, and bag breaking resistance, and it can be suitably used as a film for various packaging.

The thickness of the laminated film of the present invention may be appropriately adjusted according to the use and mode to be used. However, the total thickness is 20 because it is easy to achieve both volume reduction in packaging applications and resistance to bag breakage during distribution. It is preferably ˜60 μm, more preferably 25˜50 μm.

The thickness ratio of each layer is not particularly limited, but the print layer thickness is preferably 10 to 35% of the total thickness, the intermediate layer 45 to 85%, and the seal layer 5 to 20%. The thickness of each layer may be appropriately adjusted within the above range. For example, the thickness of the printing layer is preferably 2 to 20 μm, and more preferably 3 to 15 μm. The thickness of the intermediate layer is preferably 3 to 30 μm, more preferably 5 to 20 μm. The thickness of the seal layer is preferably 1 to 10 μm, and more preferably 2 to 8 μm.

The laminated film of the present invention may be laminated with any other resin layer other than the printed layer, intermediate layer and seal layer, but the thickness of the other resin layer is 20% or less of the total thickness. It is particularly preferable that the printing layer, the intermediate layer, and the sealing layer be used.

Although it does not specifically limit as a manufacturing method of the laminated | multilayer film of this invention, For example, the resin or resin mixture used for each layer is heat-melted with a respectively separate extruder, By methods, such as a coextrusion multilayer die method and a feed block method, etc. Examples thereof include a coextrusion method in which a film is laminated in a molten state and then formed into a film by inflation, a T-die / chill roll method, or the like. This coextrusion method is preferable because the thickness ratio of each layer can be adjusted relatively freely, and a multilayer film excellent in hygiene and cost performance can be obtained. Since the laminated film obtained by the production method is obtained as a substantially unstretched multilayer film, secondary molding such as deep drawing by vacuum molding is also possible.

The printing layer is preferably subjected to a surface treatment in order to improve adhesion with 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.

Examples of the packaging material made of the laminated film of the present invention include packaging bags, containers, container lids and the like used for foods, medicines, industrial parts, miscellaneous goods, magazines and the like.

In the packaging bag, the sealing layer of the laminated film of the present invention is used as a heat sealing layer, heat sealing is performed by stacking the sealing layers, or heat sealing is performed by stacking the printing layer and the sealing layer. A formed packaging bag is preferred. For example, after cutting the two laminated films into the desired size of the packaging bag, overlapping them and heat-sealing the three sides to form a bag, filling the contents from one side that is not heat-sealed It can be used as a packaging bag by heat sealing. Furthermore, it is also possible to form a packaging bag by sealing the upper and lower sides after sealing the end of a roll-shaped film into a cylindrical shape by an automatic packaging machine.

Moreover, when it is set as the packaging bag for bread, it can be set as the packaging bag which has a gusset part by folding and sealing a printing surface. Even when the laminated film of the present invention is a packaging bag having such a gusset portion, it can be suitably applied to the packaging bag application of the form because it can ensure a suitable fusing seal strength together with excellent printing adhesion. it can.

It is also possible to form a packaging bag, a container, and a container lid by heat-sealing another film that can be heat-sealed with a sealing layer. In this case, as another film to be used, a film such as LDPE, EVA, or polypropylene having relatively low mechanical strength can be used. Also, a laminate film in which a film of LDPE, EVA, polypropylene, etc., and a stretched film having relatively good tearability, for example, a biaxially stretched polyethylene terephthalate film (OPET), a biaxially stretched polypropylene film (OPP), etc. are bonded together. Can be used.

Next, the present invention will be described in more detail with reference to examples and comparative examples. In addition, “part” and “%” in the blending of the resin composition and the like are based on mass.

Example 1
As the resin component forming each layer of the printed layer (A), the intermediate layer, and the seal layer, the following resins were used, respectively, to prepare a resin mixture for forming each layer. These resin mixtures were supplied to a printing layer (A) extruder (caliber 50 mm), an intermediate layer (B) extruder (caliber 50 mm) and a seal layer (C) extruder (caliber 50 mm), respectively. The film is melted at ~ 230 ° C., and the melted resin is supplied to a T-die / chill roll co-extrusion multilayer film production apparatus (feed block and T-die temperature: 250 ° C.) having a feed block to perform melt extrusion, and a film A co-extruded multilayer film (X1) having a layer configuration of (A) / (B) / (C) and a thickness of each layer of 7 μm / 20 μm / 3 μm (total 30 μm) was obtained. The printed layer (A) was subjected to corona treatment so that the surface tension by the wetting reagent was 34 mN / m.
Printing layer (A): propylene-ethylene copolymer (1) [ethylene content: 4.2%, density: 0.90 g / cm ³ , MFR: 6 g / 10 min (190 ° C., 21.18 N)] 85 mass Part, styrene-ethylenebutylene-styrene block polymer (styrene content 35%, density: 0.92 g / cm ³ , MFR: 10 g / 10 min (230 ° C., 21.2 N) (hereinafter referred to as SEBS (1)) ] 15 parts by mass Intermediate layer (B): Propylene homopolymer (1) [Density: 0.90 g / cm ³ , MFR: 7.5 g / 10 min] 75 parts by mass, propylene-ethylene copolymer (2) [ Ethylene content: 5.2%, density: 0.90 g / cm ³ , MFR: 5.4 g / 10 minutes] 15 parts by mass, linear low density polyethylene [density: 0.905 g / cm ³ , MFRI: 4. 0g / 10min Between] 10 parts by mass Seal layer (C): propylene-ethylene copolymer (2) [ethylene content: 5.2%, density: 0.90 g / cm ³ , MFR: 5.4 g / 10 minutes] 50 parts by mass , 1-butene-propylene copolymer (density: 0.90 g / cm ³ , MFR: 4 g / 10 minutes) 45 parts by mass, high-density polyethylene (density: 0.955 g / cm ³ ) 5 parts by mass

(Example 2)
A coextruded multilayer film (X2) was obtained in the same manner as in Example 1 except that the resin component of the resin mixture used for the printed layer (A) was as follows. The printed layer (A) was subjected to corona treatment so that the surface tension by the wetting reagent was 34 mN / m.
Printing layer (A): Propylene-ethylene copolymer (1) 80 parts by mass, SEBS (1) 20 parts by mass

(Example 3)
A coextruded multilayer film (X3) was obtained in the same manner as in Example 1 except that the resin component of the resin mixture used for the printed layer (A) was as follows. The printed layer (A) was subjected to corona treatment so that the surface tension by the wetting reagent was 34 mN / m.
Printing layer (A): 85 parts by mass of propylene-ethylene copolymer (1), hydrogenated styrene butadiene rubber [styrene content 16%, density: 0.90 g / cm ³ , MFR: 10 g / 10 min (230 ° C., 21.2N) (hereinafter referred to as HSBR (1)) 15 parts by mass

Example 4
A coextruded multilayer film (X4) was obtained in the same manner as in Example 1 except that the resin component of the resin mixture used for the printing layer (A) was as follows. The printed layer (A) was subjected to corona treatment so that the surface tension by the wetting reagent was 34 mN / m.
Printing layer (A): Propylene-ethylene copolymer (1) 80 parts by mass, HSBR (1) 20 parts by mass

(Example 5)
Except for coextrusion so that the thickness of each layer of the laminated film formed by the printing layer (A) / intermediate layer (B) / sealing layer (C) is 5 μm / 22 μm / 3 μm (total 30 μm) In the same manner as in Example 1, a coextruded multilayer film (X5) was obtained. The printed layer (A) was subjected to corona treatment so that the surface tension by the wetting reagent was 34 mN / m.

(Example 6)
A coextruded multilayer film (X6) was obtained in the same manner as in Example 1 except that the resin component of the resin mixture used for the printed layer (A) was as follows. The printed layer (A) was subjected to corona treatment so that the surface tension by the wetting reagent was 34 mN / m.
Print layer (A): 75 parts by mass of propylene-ethylene copolymer (1), 15 parts by mass of SEBS (1), crystalline ethylene-1-butene copolymer (1) [density: 0.88 g / cm ³ , MFR: 4 g / 10 min (190 ° C., 21.18 N)] 10 parts by mass

(Example 7)
A coextruded multilayer film (X7) was obtained in the same manner as in Example 1 except that the resin component of the resin mixture used for the printed layer (A) was as follows. The printed layer (A) was subjected to corona treatment so that the surface tension by the wetting reagent was 34 mN / m.
Printing layer (A): 75 parts by mass of propylene-ethylene copolymer (1), 15 parts by mass of HSBR (1), 10 parts by mass of crystalline ethylene-1-butene copolymer (1)

(Example 8)
A coextruded multilayer film (X8) was obtained in the same manner as in Example 1 except that the resin component of the resin mixture used for the printed layer (A) was as follows. The printed layer (A) was subjected to corona treatment so that the surface tension by the wetting reagent was 34 mN / m.
Printing layer (A): 70 parts by mass of propylene-ethylene copolymer (1), styrene-ethylenebutylene-styrene block polymer [styrene content 15%, density: 0.90 g / cm ³ , MFR: 30 g / 10 min ( 230 ° C., 21.2 N) (hereinafter referred to as SEBS (2))] 20 parts by mass, crystalline ethylene-1-butene copolymer (1) 10 parts by mass

Example 9
A coextruded multilayer film (X9) was obtained in the same manner as in Example 1 except that the resin component of the resin mixture used for the printed layer (A) was as follows. The printed layer (A) was subjected to corona treatment so that the surface tension by the wetting reagent was 34 mN / m.
Printing layer (A): 70 parts by mass of propylene-ethylene copolymer (1), hydrogenated styrene butadiene rubber [styrene content 10%, density: 0.89 g / cm ³ , MFR: 10 g / 10 min (230 ° C., 21.2N) (hereinafter referred to as HSBR (2)) 20 parts by mass, crystalline ethylene-1-butene copolymer (1) 10 parts by mass

(Example 10)
A coextruded multilayer film (X10) was obtained in the same manner as in Example 1 except that the resin component of the resin mixture used for the printing layer (A) was as follows. The printed layer (A) was subjected to corona treatment so that the surface tension by the wetting reagent was 34 mN / m.
As resin for printing layer (A), 70 parts by mass of propylene-ethylene copolymer (1), polar group-modified styrene-ethylenebutylene-styrene block polymer [styrene content 25%, density: 0.91 g / cm ³ , MFR : 10 g / 10 min (230 ° C., 21.2 N) (hereinafter referred to as f-SEBS)] 20 parts by mass, crystalline ethylene-1-butene copolymer (1) 10 parts by mass

(Comparative Example 1)
A coextruded multilayer film (X11) was obtained in the same manner as in Example 1 except that the resin component of the resin mixture used for the printed layer (A) was as follows. The printed layer (A) was subjected to corona treatment so that the surface tension by the wetting reagent was 34 mN / m.
Printing layer (A): 55 parts by mass of propylene-ethylene copolymer (1), propylene-ethylene-1-butene terpolymer [density: 0.90 g / cm ³ , MFR: 5.4 g / 10 min ( 190 ° C., 21.18 N)] 35 parts by mass, crystalline ethylene-1-butene copolymer (1) 10 parts by mass

(Comparative Example 2)
After obtaining the coextruded multilayer film (X11) as in Comparative Example 1, the printed layer (A) was subjected to corona treatment so that the surface tension by the wetting reagent was 40 mN / m, to obtain the copressed multilayer film (X12). It was.

The following tests and evaluations were performed using the laminated films obtained in the above examples and comparative examples. The results obtained are as shown in the table below. In addition, the numerical value of the resin composition in a table | surface is content (mass part) of each component in the resin component used in each layer.

[Printability (ink adhesion)]
Ink (urethane type ink glosser 709 white; manufactured by DIC Corporation) was applied to the surface of the printed layer (A) of the film obtained in each of Examples and Comparative Examples at a coating amount of 12 g / m ² . The polyvinyl chloride sheet was overlaid on the coated surface, a load of 500 g / cm ² was applied, and the mixture was allowed to stand at 50 ° C. for 24 hours. The polyvinyl chloride sheet was then peeled off, and the peeling of the ink on the film surface was visually evaluated.
○: No ink is taken out ○-: Inked area is 10% or less of PVC sheet grounding surface △: Inked area is over 10% of PVC sheet grounding surface, 25% or less ×: Degree Inked area exceeds 25% of PVC sheet ground plane

[Fusing strength]
Using an impulse machine, the printed layers (A) of the films obtained in the examples and comparative examples were overlapped, and fusing sealing was performed at a temperature of 300 ° C. After the sealed film was naturally cooled at 23 ° C., a sample was cut into a strip shape having a height of 70 mm and a width of 15 mm so that the fusing seal portion was the central portion in the width direction. The cut sample was peeled off at a rate of 300 mm / min using a tensile tester (manufactured by A & D Co., Ltd.) in a thermostatic chamber at 23 ° C. and 50% Rh, and the fusing strength was measured. The heat seal strength was evaluated from the obtained fusing strength value according to the following criteria.
○: Fusing strength is 13 N / 15 mm width or more ×: Fusing strength is less than 13 N / 15 mm width

[transparency]
The haze of the films obtained in Examples and Comparative Examples was measured using a haze meter (manufactured by Nippon Denshoku Kogyo Co., Ltd.) in a constant temperature room at 23 ° C. and 50% Rh in accordance with JIS K7105. did.

[Impact strength]
The film obtained in Examples and Comparative Examples was measured for impact strength by a film impact method using a 1 inch impact diameter in a tester industry film impact tester in an environment of 0 ° C.

As is clear from the above table, the laminated films of the present invention of Examples 1 to 10 had excellent printing adhesion while having suitable fusing strength. The laminated film of the present invention was highly transparent and excellent in impact resistance. On the other hand, the laminated films of Comparative Examples 1 and 2 were unable to combine suitable fusing strength and printing adhesion.

Claims

One surface layer is a printed film, the other surface layer is a laminated film consisting of a sealing layer,
The printing layer is composed of a propylene resin and a styrene resin,
A laminated film, wherein the styrene content in the printed layer is 2 to 15% by mass.
The laminated film according to claim 1, wherein the styrenic resin of the printing layer comprises a styrenic elastomer.
The laminated film according to claim 1 or 2, wherein a wetting tension on the surface of the printing layer is 38 mN / m or less.
The laminated film according to claims 1 to 3, wherein the seal layer contains a copolymer having a structural unit composed of 1-butene.
The laminated film according to any one of claims 1 to 4, further comprising an intermediate layer containing a propylene-based resin between the print layer and the seal layer.
6. The propylene resin content in the resin component contained in the printing layer is 60 to 95% by mass, and the styrene elastomer content is 5 to 40% by mass. Laminated film.
The laminated film according to any one of claims 1 to 6, which has a haze value of 10% or less.
The laminated film according to any one of claims 1 to 7, which is used for a packaging material.
A packaging material comprising the laminated film according to any one of claims 1 to 8.
The packaging material according to claim 9, which is a packaging bag for food.