TWI686302B - Laminated film and packaging materials - Google Patents

Abstract

The present invention uses styrene-based elastomer to introduce styrene into the printed layer having a laminated film containing a printed layer of acryl-based resin, thereby maintaining a better fusion-cutting strength, and even with resin sheets such as polyvinyl chloride When the material is in contact, it is not easy to cause printing to fall off, which can achieve excellent printing adhesion. In addition, by using a styrene-based elastomer, its compatibility with the propylene-based resin becomes good, and it is possible to achieve good transparency and excellent impact resistance.

Description

Laminated film and packaging materials

The present invention relates to a laminated film used for packaging packaging materials for food, groceries, magazines, etc., and packaging materials containing the film.

Conventionally, a laminated film in which plural resins are laminated is used as a packaging film for packaging bread or other foods. From the viewpoint of easily obtaining heat sealability and the like, a laminated film using an olefin-based resin can be widely used as such a packaging film (for example, refer to Patent Documents 1 to 2).

Laminated films used in various packages are often provided with a print on the surface layer to indicate the location, content, design, etc. However, if the adhesion of the print is low, the print will fall off, so the surface is treated by corona treatment, etc. Processing to achieve improved print adhesion.

Prior technical literature Patent Literature

Patent Document 1 Japanese Patent Application Publication No. 2002-210897

Patent Literature 2 Japanese Patent Application Publication No. 2007-152730

However, in the conventional laminated film, when the printing layer is in 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 it is required to further improve the printing adhesion . On the other hand, if surface treatment such as corona treatment is performed in order to improve the printing adhesion of the surface layer of the laminated film, although the printing adhesion is improved, the film will be fused and the fused strength at the time of adhesion is likely to decrease, Therefore, it is difficult to further improve the printing adhesion by surface treatment.

The problem to be solved by the present invention is to provide a laminated film which has better fused cutting strength and can achieve excellent printing adhesion.

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

The present invention solves the above-mentioned problem by means of a laminated film: a laminated film whose surface layer on one side includes a printed layer and the surface layer on the other side includes a sealing layer, wherein the printed layer contains an acrylic resin and a styrene-based elastomer, and is printed The styrene content in the layer is 2 to 15% by mass.

In the present invention, styrene is introduced into the printed layer having a laminated film containing a printed layer of acryl-based resin through a styrene-based elastomer, thereby maintaining a better melt-cutting strength, and even with PVC When a resin sheet such as is in contact, excellent print adhesion that is difficult for printing to come off can be achieved. In addition, by using a styrene-based elastomer, the compatibility with the propylene-based resin can be improved to achieve better transparency and excellent impact resistance.

Forms for carrying out the invention

In the laminated film of the present invention, the surface layer on one side includes a printing layer for performing various printings, and the surface layer on the other side includes a sealing layer, the printing layer contains an acrylic resin and a styrene elastomer, and the styrene content in the printing layer is 2~15% by mass.

[Printed layer]

The printed layer used in the laminated film of the present invention contains an acrylic resin and a styrene elastomer. As the propylene-based resin, a propylene-based resin used for packaging films is preferably applied, and examples thereof include propylene homopolymers and propylene-α-olefin copolymers, such as propylene-ethylene copolymers and propylene-butene-1 copolymerization. Products, propylene-ethylene-butene-1 copolymer, metallocene catalyst polypropylene, etc. These copolymers can be used individually or in combination.

In particular, when the laminated film is used as a transparent laminated film, it is preferable to use a propylene-ethylene random copolymer as the resin component from the viewpoint of easily obtaining better transparency and adhesion to the intermediate layer. When a propylene-ethylene random copolymer is used, the proportion of the propylene-ethylene random copolymer in the propylene-based resin included in the printed layer is preferably 60% by mass or more, and more preferably 70% by mass or more. In addition, as the propylene-based resin, it is substantially preferable to use only a propylene-ethylene random copolymer.

As the propylene-ethylene random copolymer, from the viewpoint of easily obtaining better blocking resistance, the ethylene content is preferably 10% by mass or less, more preferably 8% by mass or less, and still more preferably 6% by mass. In addition, from the viewpoint of easily obtaining better impact resistance, the ethylene content is preferably 2% by mass or more, more preferably 3% by mass or more, and still more preferably 4% by mass or more.

In addition, the melt flow rate (MFR) of the propylene-ethylene random copolymer is not particularly limited as long as it can form a laminated film, but from the viewpoint of easily obtaining good formability, it is preferably 0.5 g/10 minutes or more, more preferably 3 g/10 minutes or more, and still more preferably 5 g/10 minutes or more. In addition, from the viewpoint of easily obtaining better impact resistance, the MFR is preferably 20 g/10 minutes or less, more preferably 15 g/10 minutes or less, and still more preferably 12 g/10 minutes or less.

The density of the propylene-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 higher, and more preferably 115° C. or higher, from the viewpoint of a decrease in rigidity leading to a decrease in the suitability for bag making or sliding properties. Moreover, from the viewpoint of cracking properties or bag breakage at low temperatures, it is preferably 150°C or lower, and more preferably 145°C or lower.

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 of the resin component contained in the printing layer. In addition, the content is preferably 95% by mass or less, and more preferably 90% by mass or less.

In the present invention, from the viewpoint of easily achieving better transparency of the laminated film, the content of the block copolymer in the resin component is preferably 10% by mass or less, more preferably 5% by mass or less, and particularly preferably substantially Not included. The laminated film of the present invention can achieve particularly good effects when a printed layer with a low content of block copolymer is used.

Examples of the styrene-based elastomer used in the printing layer include styrene-based elastomers having a styrene-based polymer block and a random copolymer of styrene and a conjugated diene compound whose hydrogenated double bonds are partially hydrogenated. Copolymer (A-1) with regular copolymer blocks; general formula aba or ab (a is a styrene polymer block, b is a conjugated diene polymer block or a conjugated diene polymer The styrene-based block copolymer (A-2) represented by the olefin polymer block obtained by partial hydrogenation of the double bond and the like. The styrene-based elastomer containing the "blocked portion where the double bond portion of the conjugated diene portion is hydrogenated" has excellent compatibility with the propylene-based resin, so it is easy to obtain excellent transparency.

As the conjugated diene compound used as a raw material of the copolymer (A-1) or (A-2), for example, 1,3-butadiene, isoprene, 2,3-dimethyl -1,3-pentadiene, 2-methyl-1,3-pentadiene, 1,3-hexadiene, 4,5-diethyl-1,3-octadiene, 3-butyl -1,3-octadiene, chloroprene and the like are preferably 1,3-butadiene and isoprene from the viewpoint of industrial availability. In addition, examples of the styrene-based compound forming the styrene-based polymer block include styrene, α-methylstyrene, p-methylstyrene, tert-butylstyrene, divinylbenzene, and 1, 1-Diphenylstyrene, N,N-dimethyl-p-aminomethylstyrene, N,N-diethyl-p-aminoethylstyrene, etc., but styrene is preferably used.

As a commercially available product, for example, as the copolymer (A-1), for example, styrene-butadiene random copolymer hydride (hereinafter abbreviated as HSBR) manufactured by JSR Corporation "DYNARON 1320P, DYNARON 2320P" Also, examples of the styrene-based block copolymer (A-2) include: "SIS5200" manufactured by JSR Co., Ltd. of styrene-isoprene-styrene block copolymer (hereinafter abbreviated as SIS). ", styrene-ethylene-butene-styrene block copolymer (hereinafter referred to as SEBS) "DYNARON 8600P, DYNARON 8903P made by JSR Co., Ltd.", styrene-ethylene. "SEPTON 2063, SEPTON 2004" manufactured by KURARAY Co., Ltd. of propylene-styrene block copolymer (hereinafter abbreviated as SEPS), etc.

In the present invention, in order to improve the adhesion of printing, the styrene content relative to the resin component in the printing layer is preferably 2% by mass or more, more preferably 2.5% by mass or more, and still more preferably 3% by mass or more. In order to suppress the decrease in transparency, the styrene content in the printed layer is preferably 15% by mass or less, and more preferably 13% by mass or less.

The content of the styrene-based elastomer in the printed layer may be appropriately adjusted so that the styrene content is within the above range, but in order to suppress the reduction in rigidity, it is preferably 40% by mass or less of the resin component contained in the printed layer. It is more preferably 30% by mass or less. In addition, the lower limit is not particularly limited, but it is preferably 5% by mass or more, and more preferably 10% by mass or more.

Other resins other than the above-mentioned acrylic resin and styrene elastomer may be appropriately used in combination in the printed layer. As this other resin, olefin resins other than the above, for example, polyethylene resins such as ultra-low density polyethylene (VLDPE), linear low density polyethylene (LLDPE), low density polyethylene (LDPE), etc.; ethylene- Vinyl acetate copolymer (EVA), ethylene-methyl methacrylate copolymer (EMMA), ethylene-ethyl acrylate copolymer (EEA), ethylene-methyl acrylate (EMA) copolymer, ethylene-ethyl acrylate- Ethylene copolymers such as maleic anhydride copolymers (E-EA-MAH), ethylene-acrylic acid copolymers (EAA), ethylene-methacrylic acid copolymers (EMAA), etc. Furthermore, ionic polymerization of ethylene-acrylic acid copolymers Ionic polymer of ethylene-methacrylic acid copolymer, etc.

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

Anti-fogging agents, antistatic agents, heat stabilizers, nucleating agents, antioxidants, slip agents, anti-caking agents, mold release agents can be added to the printed layer as long as the purpose of the present invention is not compromised , Ultraviolet absorbers and other components as other components than the above resin components.

Preferably, the surface of the printed layer is treated so that the wetting tension of the surface is in the range of 38 mN/m or less, more preferably 35 mN/m or less. If the wetting tension is within this range, the fused cutting strength will not be greatly reduced, and the printing adhesion can be improved. As the surface treatment method, for example: corona discharge treatment, plasma treatment, chromic acid treatment, flame treatment, hot air treatment, ozone. Among them, surface oxidation treatment such as ultraviolet treatment, surface roughness treatment such as sandblasting, etc., among which corona discharge treatment is preferred. In addition, the lower limit of the wetting tension is not particularly limited, but it is preferably 30 mN/m or more.

[Sealing layer]

The sealing layer used in the present invention is a layered body for adhering the sealing layers of the laminated film to each other or the laminated film and other containers or films. As for the sealing layer, it is only necessary to appropriately select the type of resin that can obtain a better sealing strength in accordance with the aspect of use or the object to be sealed. For example, in the case where the sealing layers are sealed to each other to be used as a packaging bag, from the viewpoint of obtaining a moderate seal strength, it is preferable to use propylene-ethylene-containing (no (Regulation) Sealing layers of propylene-α-olefin copolymers such as copolymers and propylene-1-butene copolymers, among them, particularly preferred is a sealing layer containing a 1-butene-propylene copolymer.

In the case of using a 1-butene-propylene copolymer, the sealing layer may be a sealing layer containing a 1-butene-propylene copolymer, but from the viewpoint of easily suppressing cracking, the resin component contained in the sealing layer The content of the 1-butene-propylene copolymer in the medium is preferably 55% by mass or less, more preferably 50% by mass or less, and still more preferably 45% by mass or less. In addition, from the viewpoint of easily obtaining better low-temperature sealing properties, the propylene content is preferably 2 mol% or more, more preferably 3 mol% or more, and still more preferably 5 mol% or more.

In addition, when a 1-butene-propylene copolymer is used, its content is preferably 10% by mass or more, and more preferably 15% by mass or more. If the content of the 1-butene-propylene copolymer is within this range, it is easy to obtain good low-temperature sealing properties and crack resistance, and it is also advantageous for cost reduction.

As the resin used in combination with the above 1-butene-propylene copolymer, other polyolefin-based resins can be suitably used, but from the viewpoint of easy adjustment of the seal strength, preferably other than 1-butene-propylene copolymer Propylene-α-olefin copolymer and ethylene-α-olefin copolymer.

The content of α-olefin in the 1-butene-propylene copolymer or ethylene-α-olefin copolymer is not particularly limited, but it is preferably 1 to 20% by mass, and more preferably 1.5 to 15% by mass. As the α-olefin, ethylene, propylene, 1- Butene, 1-hexene, 4-methyl-1-pentene, 1-octene, etc. Among them, the propylene-ethylene random copolymer listed above in the intermediate layer is preferably used. From the viewpoint of easily obtaining good formability, the MFR is preferably 0.5 to 20 g/10 minutes, and more preferably 2 to 10 g/10 minutes.

In the case of containing a 1-butene-propylene copolymer, it is easy to adjust the heat sealing temperature or strength at the time of easy opening and sealing at a low temperature, and the heat sealing temperature range is large, and it is easy to obtain a moderate heat sealing strength for easy opening and sealing. In order to obtain an easy-opening strength of 2 to 6 N/15 mm, it is preferable to use a resin layer formed by using a 1-butene-propylene copolymer and a propylene copolymer in combination at a weight ratio of 20/80 to 50/50, and As the 1-butene-propylene copolymer used here, it is particularly preferable that the content of the component derived from 1-butene is 60 to 95 mol%.

Anti-fogging agents, antistatic agents, heat stabilizers, nucleating agents, antioxidants, slip agents, anti-caking agents, mold release can also be added to the sealing layer as long as the object of the present invention is not compromised Agents, ultraviolet absorbers and other components are used as components other than the above resin components.

[middle layer]

In the laminated film of the present invention, it is also preferable to appropriately design an intermediate layer between the printing layer and the sealing layer. As the intermediate layer, an olefin-based resin is preferably used.

As the olefin-based resin used for the intermediate layer, for example, propylene-α-olefin copolymer (propylene-butene-1 copolymer, propylene-ethylene-butene-1 copolymer, metallocene catalyst-based polypropylene, etc. can be used ), propylene homopolymer, ultra low density polyethylene (VLDPE), linear low density polyethylene (LLDPE), low density polyethylene (LDPE) and other polyethylene resins; ethylene-vinyl acetate copolymer (EVA), 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) and other ethylene-based copolymers; furthermore, ethylene-acrylic acid copolymer ionic polymer, ethylene-methacrylic acid copolymer Ionic polymers, etc. These ingredients can be used individually or in combination.

Among them, from the viewpoint of adhesion to the printing layer and the sealing layer, it is preferable to use a propylene-based resin that can be used in the printing layer, for example, it is preferable to use a propylene homopolymer and a propylene-α-olefin copolymer, for example Propylene-ethylene copolymer, propylene-butene-1 copolymer, propylene-ethylene-butene-1 copolymer, metallocene catalyst-based polypropylene, etc. These ingredients can be used individually or in combination.

In addition, according to demand, more than one type of propylene resin can be used as the main component, and its content is preferably 75% by mass or more, and mixed with ultra-low density polyethylene (VLDPE), linear low density polyethylene (LLDPE), low Polyethylene resins such as density polyethylene (LDPE); ethylene-vinyl acetate copolymer (EVA), ethylene-methyl methacrylate copolymer (EMMA), ethylene-propylene Ethyl acrylate copolymer (EEA), ethylene-methyl acrylate (EMA) copolymer, ethylene-ethyl acrylate-maleic anhydride copolymer (E-EA-MAH), ethylene-acrylic acid copolymer (EAA), ethylene -Ethylene copolymers such as methacrylic acid copolymers (EMAA); ionic polymers of ethylene-acrylic acid copolymers, ionic polymers of ethylene-methacrylic acid copolymers, etc.

Anti-fogging agents, antistatic agents, heat stabilizers, nucleating agents, antioxidants, slip agents, anti-caking agents, mold release can also be added to the intermediate layer as long as the purpose of the present invention is not compromised Agents, ultraviolet absorbers and other components are used as components other than the above resin components.

[Laminated Film]

The laminated film of the present invention is a laminated film having at least the above-mentioned printed layer, intermediate layer, and sealing layer, and the surface layer on one side of the laminated film includes a printed layer, and the surface layer on the other side includes a sealing layer. The laminated film of this structure has good packaging applicability, and is not easily cracked when the contents are loaded, and can achieve better crack resistance. In addition, it is easy to achieve good fusion seal strength, impact resistance, and bag-break resistance, and is suitable for use as a film for various packaging.

The thickness of the laminated film of the present invention may be appropriately adjusted according to the application or form to be used, but from the viewpoint of easy combination of volume reduction in packaging applications and resistance to bag breakage during delivery The total thickness is preferably 20-60 μm, more preferably 25-50 μm.

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

The laminated film of the present invention may be laminated with any other resin layer other than the above-mentioned printed layer, intermediate layer, and sealing layer, but the thickness of the other resin layer is preferably 20% or less of the total thickness, particularly preferably including the above-mentioned printed layer, intermediate The composition of the layer and the sealing layer.

The manufacturing method of the laminated film of the present invention is not particularly limited, and for example, the following co-extrusion method: each resin or resin mixture used for each layer is heated and melted by each extruder, and then the multi-layer die method by co-extrusion or After the feeding equipment method and other methods are laminated in the molten state, by the blowing method or T-shaped mold. It is formed into a film shape by a cooling roll method or the like. This co-extrusion method can adjust the thickness ratio of each layer relatively freely, and can obtain a multilayer film with excellent hygiene and excellent cost performance, which is preferable. The laminated film obtained by this manufacturing method can substantially obtain a non-stretched multi-layer film, and therefore secondary forming such as deep drawing forming can also be performed by vacuum forming.

In order to improve adhesion to printing ink, etc., it is also preferable to perform surface treatment on the printing layer. As such surface treatment, for example: corona treatment, plasma treatment, chromic acid treatment, flame treatment, hot air treatment, ozone. Surface oxidation treatment such as ultraviolet treatment or surface roughness treatment such as sandblasting is preferred, but corona treatment is preferred.

Examples of the packaging material including the laminated film of the present invention include packaging bags, containers, and covering materials for containers used in applications such as food, medicine, industrial parts, groceries, and magazines.

The packaging bag is preferably a packaging bag formed by using the sealing layer of the laminated film of the present invention as a heat sealing layer, overlapping the sealing layers with each other to perform heat sealing, or overlapping the printed layer and the sealing layer Heat sealing is performed, whereby the sealing layer is used as the inner side. For example, after cutting two pieces of the laminated film into a desired bag size, overlapping them, and heat-sealing the three sides to form a bag shape, filling the contents from the unheated one side, and then heat-sealing , Which can be used as a packaging bag. Furthermore, the end of the drum-shaped film can be sealed into a cylindrical shape by an automatic packaging machine, and the packaging bag can be formed by sealing the top and bottom.

In addition, in the case of forming a bag for long bread, by folding and sealing the printing surface inward, a bag with a folded portion can be formed. The laminated film of the present invention, even in the case of forming a packaging bag having such a hemming portion, can ensure excellent printing adhesion and better fusion seal strength, so it is particularly suitable for packaging bags of this form use.

In addition, the outer cover of the packaging bag, the container, and the container may also be formed by overlapping the sealing layer with other heat-sealable films and heat-sealing. At this time, as other films used, films with low mechanical strength such as LDPE, EVA, and polypropylene can be used. In addition, LDPE, EVA, polypropylene and other films and stretch films with good tearability, such as biaxially stretched polyethylene terephthalate film (OPET) and biaxially stretched polypropylene film (OPP), can also be used The laminated film to be laminated.

[Example]

Next, the present invention will be described in more detail with examples and comparative examples. In addition, "parts" and "%" in the blending of resin composition and the like are quality standards.

(Example 1)

The following various resins are used as the resin component of each layer forming the printing layer (A), the intermediate layer, and the sealing layer, and the resin mixture forming each layer is adjusted. These resin mixtures were supplied to an extruder (caliber 50 mm) for the printing layer (A), an extruder (caliber 50 mm) for the intermediate layer (B) and an extruder (caliber 50 mm) for the sealing layer (C), Melt at 200 ~ 230 ℃, the molten resin is supplied to the T-shaped mold with feeding equipment. The co-extrusion multilayer film manufacturing apparatus (feeding equipment and T-die temperature: 250°C) of the cooling roll method was melt-extruded to obtain a film layer structure consisting of three layers (A)/(B)/(C) A co-extruded multilayer film (X1) composed of 7 μm/20 μm/3 μm (total 30 μm) in each layer. so that The surface tension measured by the wet reagent is 34mN/m, and the corona treatment is performed on the printed layer (A).

Printed layer (A): propylene-ethylene copolymer (1) [ethylene content: 4.2%, density: 0.90 g/cm ³ , MFR: 6 g/10 minutes (190°C, 21.18N)] 85 parts by mass, styrene- Ethylene butene-styrene block polymer [styrene content 35%, density: 0.92g/cm ³ , MFR: 10g/10 minutes (230°C, 21.2N) (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 minutes] 75 parts by mass, propylene-ethylene copolymer (2) [ethylene content: 5.2%, density : 0.90g/cm ³ , MFR: 5.4g/10 minutes] 15 parts by mass, linear low-density polyethylene [density: 0.905g/cm ³ , MFRI: 4.0g/10 minutes] 10 parts by mass

Sealing 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: 0.90g/cm ³ , MFR: 4g/10min) 45 parts by mass, high density polyethylene (density: 0.955g/cm ³ ) 5 parts by mass

(Example 2)

A co-extruded multilayer film (X2) was obtained in the same manner as in Example 1, except that the resin composition of the resin mixture used for the printing layer (A) was changed to the following composition. The printed layer (A) was subjected to corona treatment so that the surface tension measured by the wet reagent was 34 mN/m.

Printed layer (A): 80 parts by mass of propylene-ethylene copolymer (1), 20 parts by mass of SEBS (1)

(Example 3)

A co-extruded multilayer film (X3) was obtained in the same manner as in Example 1, except that the resin composition of the resin mixture used for the printing layer (A) was changed to the following composition. The printed layer (A) was subjected to corona treatment so that the surface tension measured by the wet reagent was 34 mN/m.

Printed 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 minutes (230°C, 21.2N) (hereinafter referred to as HSBR (1)) 15 parts by mass

(Example 4)

A co-extruded multilayer film (X4) was obtained in the same manner as in Example 1, except that the resin composition of the resin mixture used for the printing layer (A) was changed to the following composition. The printed layer (A) was subjected to corona treatment so that the surface tension measured by the wet reagent was 34 mN/m.

Printed layer (A): 80 parts by mass of propylene-ethylene copolymer (1), 20 parts by mass of HSBR (1)

(Example 5)

Except for co-extrusion in such a way that the thickness of each layer of the laminated film formed by the printed layer (A)/intermediate layer (B)/sealing layer (C) was 5 μm/22 μm/3 μm (total 30 μm) 1 A co-extruded multilayer film (X5) was obtained in the same way. The printed layer (A) was subjected to corona treatment so that the surface tension measured by the wet reagent was 34 mN/m.

(Example 6)

A co-extruded multilayer film (X6) was obtained in the same manner as in Example 1, except that the resin composition of the resin mixture used for the printing layer (A) was changed to the following composition. The printed layer (A) was subjected to corona treatment so that the surface tension measured by the wet reagent was 34 mN/m.

Printed 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: 4g/10min (190℃, 21.18N)] 10 parts by mass

(Example 7)

A co-extruded multilayer film (X7) was obtained in the same manner as in Example 1, except that the resin composition of the resin mixture used for the printing layer (A) was changed to the following composition. The printed layer (A) was subjected to corona treatment so that the surface tension measured by the wet reagent was 34 mN/m.

Printing layer (A): 75 parts by mass of propylene-ethylene copolymer (1), 15 parts by mass of HSBR (1), and 10 parts by mass of crystalline ethylene-1-butene copolymer (1)

(Example 8)

A co-extruded multilayer film (X8) was obtained in the same manner as in Example 1, except that the resin composition of the resin mixture used for the printing layer (A) was changed to the following composition. The printed layer (A) was subjected to corona treatment so that the surface tension measured by the wet reagent was 34 mN/m.

Print layer (A): 70 parts by mass of propylene-ethylene copolymer (1), styrene-ethylene butene-styrene block polymer [styrene content 15%, density: 0.90 g/cm ³ , MFR: 30 g/ 10 minutes (230°C, 21.2N), (hereinafter referred to as SEBS(2))] 20 parts by mass, 10 parts by mass of crystalline ethylene-1-butene copolymer (1)

(Example 9)

A co-extruded multilayer film (X9) was obtained in the same manner as in Example 1, except that the resin composition of the resin mixture used for the printing layer (A) was changed to the following composition. The printed layer (A) was subjected to corona treatment so that the surface tension measured by the wet reagent was 34 mN/m.

Printed 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 minutes (230°C, 21.2N) (hereinafter referred to as HSBR (2)) 20 parts by mass, 10 parts by mass of crystalline ethylene-1-butene copolymer (1)

(Example 10)

A co-extruded multilayer film (X10) was obtained in the same manner as in Example 1, except that the resin composition of the resin mixture used for the printing layer (A) was changed to the following composition. The printed layer (A) was subjected to corona treatment so that the surface tension measured by the wet reagent was 34 mN/m.

As a resin for the printing layer (A), 70 parts by mass of a propylene-ethylene copolymer (1), a polar group-modified styrene-ethylene butene-styrene block polymer [styrene content 25%, density: 0.91 g/ cm ³ , MFR: 10 g/10 minutes (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 co-extruded multilayer film (X11) was obtained in the same manner as in Example 1, except that the resin composition of the resin mixture used for the printing layer (A) was changed to the following composition. The printed layer (A) was subjected to corona treatment so that the surface tension measured by the wet reagent was 34 mN/m.

Printed 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 minutes (190°C, 21.18N)] 35 parts by mass, 10 parts by mass of crystalline ethylene-1-butene copolymer (1)

(Comparative example 2)

After the co-extruded multilayer film (X11) was obtained in the same manner as in Comparative Example 1, the printed layer (A) was subjected to corona treatment so that the surface tension measured by the wet reagent was 40 mN/m to obtain a co-extruded multilayer Thin film (X12).

Using the laminated films obtained in the above examples and comparative examples, the following tests and evaluations were performed. The results obtained are shown in the table below. In addition, the numerical value of the resin composition in the table is the content (parts by mass) of each component in the resin components in each layer.

[Printing applicability (ink adsorption)]

An ink (urethane type ink Grossa709 white; manufactured by DIC) was applied at a coating amount of 12 g/m ^{2 on} the surface of the printed layer (A) of the film obtained in Examples and Comparative Examples. The polyvinyl chloride sheet was overlaid on the coated surface, a load of 500 g/cm ² was applied, and after standing at 50° C. for 24 hours, the polyvinyl chloride sheet was peeled off, and the ink peeling off on the surface of the evaluation film was visually confirmed.

○: No ink drop

○-: The area where the ink falls off is less than 10% of the contact surface of the PVC sheet

△: The area where the ink drops off exceeds 10% of the contact surface of the PVC sheet, and is less than 25%

×: The area where the ink falls off exceeds 25% of the contact surface of the PVC sheet

[Fuse Cutting Strength]

Using a pulse machine, the printed layers (A) of the films obtained in Examples and Comparative Examples were overlapped with each other, and the fusion cut sealing was performed at a temperature of 300°C. After the sealed film was naturally cooled at 23° C., the sample was cut into an elongated sheet shape with a height of 70 mm and a width of 15 mm so that the fusion cut seal portion was the central portion in the width direction. In a thermostatic chamber at 23° C. and 50% Rh, using a tensile tester (manufactured by A&D Co., Ltd.), the cut sample was peeled off at a speed of 300 mm/minute, and the fused shear strength was measured. The heat seal strength was evaluated from the obtained value of the fused shear strength on the following criteria.

○: The fusing strength is above 13N/15mm

×: The fusion cutting strength is less than 13N/15mm

[Transparency]

In a constant temperature room at 23° C. and 50% Rh, the haze of the films obtained in Examples and Comparative Examples was measured using a haze meter (manufactured by Nippon Electric Industry Co., Ltd.) in accordance with JIS K7105.

[Impact strength]

The impact strength of the films obtained in Examples and Comparative Examples was measured by a film impact method using a film impact tester made by TESTER SANGYO under a 0°C environment using a 1 inch impact shaft diameter.

As is clear from the above table, the laminated films of the present invention of Examples 1 to 10 have better fused cutting strength and excellent print adhesion. In addition, the laminated film of the present invention has high transparency and excellent impact resistance. On the other hand, the laminated films of Comparative Examples 1 to 2 cannot have both better squeeze strength and print adhesion.

Claims (9)

A laminated film having a printed layer on one side and a sealing layer on the other side, characterized in that the printed layer includes an acrylic resin and a styrene elastomer, and the styrene in the printed layer The content is 2~15% by mass. The laminated film according to claim 1, wherein the wet tension of the surface of the printed layer is 38 mN/m or less. The laminated film according to claim 1 or 2, wherein the sealing layer contains a copolymer having a structural unit containing 1-butene. The laminated film according to claim 1 or 2, wherein an intermediate layer containing an acrylic resin is provided between the printed layer and the sealing layer. The laminated film according to claim 1 or 2, wherein the content of the acrylic resin in the resin component contained in the printed layer is 60 to 95% by mass, and the content of the styrene elastomer is 5 to 40% by mass. The laminated film according to claim 1 or 2, wherein the haze value is 10% or less. The laminated film of claim 1 or 2 is used for packaging materials. A packaging material characterized by comprising the laminated film according to any one of claims 1 to 7. If the packaging material of claim 8 is a food packaging bag.