TW201940574A - Multilayer film and food-packaging bag - Google Patents

Abstract

A multilayer film which comprises superposed layers including a surface layer (A), an interlayer (B), and a sealing layer (C), wherein the surface layer (A), interlayer (B), and sealing layer (C) each comprise a propylene-based resin and the interlayer (B) includes plant-derived biomass polyethylene (b1), the biomass polyethylene (b1) having a melt flow rate of 1.5 g/10 min or higher. The multilayer film, although including a plant-derived resin ingredient, renders not only suitable sealing strength and impact resistance but also satisfactory fusion-sealing strength in a wide temperature range possible.

Description

Laminated film and food packaging bag

The present invention relates to a laminated film and a food packaging bag using plant-derived raw materials.

In recent years, in order to reduce the environmental load, we have investigated the use of resin-derived components derived from petroleum and other fossil fuels as the main component as part of the raw materials of resin films used in packaging materials. Composition of resin.

As a resin film using a plant-derived resin, it is disclosed that, for example, a sealant film used in a laminated tube or a stand-up ply is laminated with a substrate, and a plant-derived linear low-density polyethylene sealant film is used (see Patent Documents 1 to 2), or a cover material including a sealant layer using a plant-derived low-density biomass polyethylene and a substrate (Patent Document 3) and the like.

[Prior technical literature] [Patent Literature]

Patent Document 1: Japanese Patent Application Laid-Open No. 2016-145086

Patent Document 2: Japanese Patent Application Publication No. 2012-167172

Patent Document 3: Japanese Patent Application Publication No. 2015-231870

Although plant-derived resins are highly environmentally compatible, they often exhibit properties different from those of fossil fuel-derived resins. If they are substituted only, heat sealability, impact resistance, and bag breakage resistance may be reduced. However, when the resin film disclosed in the above-mentioned document is a plant-derived resin, when it is applied to a stand-up bag or a cover material, because it is laminated with a laminated substrate, it is not considered at all if it does not have a laminated substrate. Impact resistance or bag breakage resistance of the thin film structure.

In addition, in the case where a packaging bag is to be applied to various packaging forms by melting sealing, it is necessary to have melting sealing performance, and in order to achieve appropriate sealing performance under manufacturing conditions according to various uses, it is expected to be widely used. Temperature zone has good melt seal strength.

In addition, the resin film disclosed in the above-mentioned document is mainly composed of a vinyl-based resin, but it is also desirable to replace a resin derived from a fossil fuel with a resin derived from a plant in a film structure mainly composed of a propylene-based resin.

The problem to be solved by the present invention is to provide a laminated film which uses a plant-derived component in a film structure mainly composed of an acrylic resin, and has suitable sealing strength or impact resistance, and has a wide temperature range. The area has good melt seal strength.

In particular, when a large amount of plant-derived ingredients are contained, a laminated film having an appropriate sealing strength or impact resistance is also provided, and a laminated film is provided, which is used in a film structure mainly composed of an acrylic resin, and is applied. Resin-derived ingredients without using Laminated substrates can also achieve appropriate seal strength or impact resistance.

The present invention solves the above-mentioned problem by a laminated film, which is a laminated film comprising a surface layer (A), an intermediate layer (B), and a sealing layer (C), the surface layer (A), the intermediate layer (B), and a seal The layer (C) contains a propylene-based resin, and the intermediate layer (B) contains a plant-derived biomass polyethylene (b1), and the melt polyethylene (b1) has a melt flow rate of 1.5 [g / 10min] or more.

Since the laminated film of the present invention uses a plant-derived resin, it also has suitable sealing strength and impact resistance, and has good melt sealing strength in a wide temperature range, so it can be suitably used as various packaging materials. In particular, it has excellent impact resistance even if it has a non-laminated base material structure. Therefore, it can be suitably used as a packaging bag for pillow packaging or corner packaging. In particular, since the laminated film of the present invention is also excellent in melt strength, it is suitable for use as a corner bag for packaging food such as bread.

[Form of Implementing Invention]

The laminated film of the present invention is a laminated film having at least a surface layer (A), an intermediate layer (B), and a sealing layer (C), and one surface layer thereof includes the surface layer (A) and the other surface layer includes the sealing layer (C), The surface layer (A), the intermediate layer (B), and the sealing layer (C) contain an acrylic resin, and the intermediate layer (B) contains a plant-derived biomass polyethylene (b1). Melt flow rate It is 1.5 [g / 10min] or more.

[Surface layer (A)]

The surface layer (A) used in the laminated film of the present invention is a layer constituting a surface layer such as a printed layer provided with a packaging film. This surface layer contains a propylene-based resin as a main resin component, and as the propylene-based resin, for example, a homopolymer of propylene, a propylene-α-olefin copolymer (propylene-α-olefin random copolymer, propylene- α-olefin block copolymer) and the like.

From the viewpoint of easily obtaining appropriate melt strength or bag-making suitability, the content of the propylene-based resin in the resin component contained in the surface layer (A) is preferably 50% by mass or more, and more preferably 70% by mass or more. It is more preferably 80% by mass or more, and particularly preferably 85% by mass or more. Moreover, the resin component contained in the surface layer (A) may be a surface layer which contains substantially only an acrylic resin.

The α-olefin content in the propylene-α-olefin copolymer is preferably 10% by mass or less, more preferably 8% by mass or less, and still more preferably 6% by mass. From the viewpoint of easily obtaining appropriate impact resistance, the α-olefin content is preferably 2% by mass or more, more preferably 3% by mass or more, and even more preferably 4% by mass or more.

When the laminated film of the present invention is formed as a transparent film, as the propylene resin used in the surface layer (A), a propylene-α-olefin random copolymer can be preferably used. Examples of the propylene-α-olefin random copolymer include a propylene-ethylene random copolymer, a propylene-1-butene random copolymer, and a propylene-ethylene-1-butene random copolymer. It can also be used together. Among them, it is preferable from the viewpoint of easily obtaining appropriate transparency. A propylene-ethylene random copolymer can be used.

The melt flow rate (MFR) of the propylene-ethylene random copolymer is not particularly limited as long as it is a range capable of forming a laminated film, but is preferably 0.5 g / 10 minutes or more, more preferably 3 g / 10 minutes or more, and further More preferably, it is 5 g / 10 minutes or more. In order to obtain good moldability, the MFR is preferably 20 g / 10 minutes or less, more preferably 15 g / 10 minutes or less, and even more preferably 12 g / 10 minutes or less.

A propylene - ethylene random copolymer has a density, preferably 0.880g / cm ³ or more 0.905g / cm ³ or less, more preferably 0.890g / cm ³ or more 0.900g / cm ³ or less.

From the viewpoint of preventing adhesion to the melted sealing knife during bag making, the melting point of the propylene-ethylene random copolymer is preferably 110 ° C or higher, and more preferably 115 ° C or higher. In addition, in the case of melting and sealing at the time of bag-making, it is necessary to form sufficient melting spheres in order to exhibit the melting and sealing strength. Therefore, it is preferably 150 ° C or lower, more preferably 145 ° C or lower.

When a propylene-ethylene random copolymer is used, the content of the propylene-ethylene random copolymer in the resin component contained in the surface layer (A) is preferably from the viewpoint of easily obtaining appropriate transparency or packaging suitability. It is 35% by mass or more, more preferably 45% by mass or more, and even more preferably 50% by mass or more. The content is preferably 75% by mass or less, more preferably 65% by mass or less, and still more preferably 60% by mass or less.

From the viewpoint of easily forming sufficient melted balls during melt sealing, it is preferable to use a random copolymerization such as a propylene-1-butene copolymer or a propylene-ethylene-1-butene copolymer having a lower melting point in combination. And random propylene-ethylene copolymers described above. Among them, it is particularly preferable to use a propylene-ethylene-1-butene copolymer. Polymer.

As the propylene-ethylene-1-butene copolymer, the ethylene content and the butene content of the propylene-ethylene-1-butene copolymer are each preferably 25% by mass or less, more preferably 15% by mass or less, and still more preferably It is 10% by mass. From the viewpoint of easily obtaining suitable low-temperature sealing properties, the ethylene content and the butene content are each preferably 0.5% by mass or more, more preferably 1.5% by mass or more, and even more preferably 3% by mass or more.

The melt flow rate (MFR) of the propylene-ethylene-1-butene copolymer is not particularly limited as long as it is a range capable of forming a laminated film, but it is preferably 0.5 g / 10 minutes or more, and more preferably 3.0 g / 10. Minutes or more, more preferably 5.0 g / 10 minutes or more. In order to obtain good moldability, the MFR is preferably 20 g / 10 minutes or less, more preferably 15 g / 10 minutes or less, and even more preferably 12 g / 10 minutes or less.

Propylene - ethylene-1-butene copolymer density, preferably 0.880g / cm ³ or more 0.905g / cm ³ or less, more preferably 0.890g / cm ³ or more 0.900g / cm ³ or less.

From the viewpoint of preventing adhesion to the melted sealing knife during bag making, the melting point of the propylene-ethylene-1-butene copolymer is preferably 105 ° C or higher, and more preferably 110 ° C or higher. In addition, in the case of melting and sealing at the time of bag-making, it is necessary to form sufficient melting balls in order to exhibit the melting and sealing strength. Therefore, it is preferably 145 ° C or lower, and more preferably 140 ° C or lower.

When a propylene-ethylene-1-butene copolymer is used, the content of the propylene-ethylene-1-butene copolymer in the resin component contained in the surface layer is smaller than that from the viewpoint of easily obtaining an appropriate melt-sealing strength. 15 mass% or more, 25 mass% or more, 30 masses or more Amount above. The content is preferably 55% by mass or less, more preferably 45% by mass or less, and still more preferably 40% by mass or less.

On the other hand, when the laminated film of the present invention is formed into a matte film, as the propylene-based resin used in the surface layer (A), a propylene-based block copolymer resin is preferably used, and particularly preferably propylene- Alpha-olefin block copolymer. Examples of the α-olefin include ethylene, 1-butene, 1-hexene, 4-methyl-1-pentene, and 1-octene. Among them, since the balance of matting feeling, cold resistance, and rigidity is excellent, Ethylene is preferred.

From the viewpoint of easy forming and easy to obtain appropriate impact resistance or matting feeling, the melt flow rate (MFR) of the propylene-based block copolymer resin is preferably 0.5 g / 10 minutes or more, more preferably 1 g / More than 10 minutes. It is preferably 20 g / 10 minutes or less, and more preferably 10 g / 10 minutes or less.

From the viewpoint of easily obtaining appropriate bag-making properties, the melting point of the propylene-based block copolymer resin is preferably 155 ° C or higher, and more preferably 165 ° C or lower.

The propylene-based block copolymer resin used in the surface layer (A) may be a single copolymer or a plurality of copolymers. When a plurality is used, the total amount of the content of the propylene-based block copolymer resin used is preferably set to the following range.

Examples of the propylene-based block copolymer resin used in the surface layer (A) and having excellent balance with matting feeling, melt strength, and bag-making suitability include BC8, BC7 (manufactured by Japan Polypropylene Corporation), E150GK, F704V (Manufactured by Prime Polymer), PC480A, PC684S, PC380A, VB370A (manufactured by SunAllomer), and the like.

When using a propylene-based block copolymer resin as the propylene-based resin, as for the content of the propylene-based block copolymer in the resin component contained in the surface layer (A), the balance of matting feeling, melt strength, or bag-making suitability is appropriately adjusted. It is sufficient, but it is preferably 50% by mass or more of the resin component used in the surface layer (A), and more preferably 70% by mass or more. By setting it as this range, it becomes easy to obtain the uniform matte feeling excellent in design property. Among them, in the case of improving the impact resistance, it is preferably set to 80 to 100% by mass, and in the case of improving the matting feeling, it is preferably set to 70 to 90% by mass.

In the surface layer (A), various olefin-based resins other than the above-mentioned propylene-based resins used for packaging films may be used. Examples of the olefin-based resin other than the propylene-based resin include polyethylene resins such as ultra-low density polyethylene (VLDPE), linear low density polyethylene (LLDPE), and low density polyethylene (LDPE), or ethylene-1. -Butene copolymerization, ethylene-vinyl acetate copolymer (EVA), ethylene-methyl methacrylate copolymer (EMMA), ethylene-ethyl acrylate copolymer (EEA), ethylene-methyl acrylate (EMA) copolymerization Polymers, ethylene-ethyl acrylate-maleic anhydride copolymer (E-EA-MAH), ethylene-acrylic acid copolymer (EAA), ethylene-methacrylic acid copolymer (EMAA) and other ethylene-based copolymers; even ethylene-acrylic acid Ionic polymers of copolymers, ionic polymers of ethylene-methacrylic acid copolymers, etc. When using an olefin-based resin other than these propylene-based resins, it is preferred that the content of the olefin-based resin in the resin component contained in the surface layer (A) is 20% by mass or less.

In the present invention, since it has flexibility in a wide effective temperature range during bag making, and good dispersibility with propylene resin can be obtained, ethylene-1-butyl is preferably used among the olefin resins. Ene Copolymer. Especially when forming into a transparent film, this copolymer can be used especially well. When using this ethylene-1-butene copolymer, it is preferable that the content of the ethylene-1-butene copolymer in the resin component contained in the surface layer is 1 from the viewpoint of obtaining an appropriate low-temperature seal. ~ 20 mass%, more preferably 5 to 15 mass%.

The MFR (230 ° C, 21.18N) of the ethylene-1-butene copolymer is not particularly limited as long as it is a range capable of forming a laminated film, but it is preferably 0.5 g / 10 minutes or more, and more preferably 2.0 g / 10. Minutes or more, more preferably 3.0 g / 10 minutes or more. In order to obtain good moldability, the MFR is preferably 20 g / 10 minutes or less, more preferably 15 g / 10 minutes or less, and even more preferably 10 g / 10 minutes or less.

The density of the ethylene 1-butene copolymer, preferably 0.870g / cm ³ or more 0.900g / cm ³ or less, more preferably 0.875g / cm ³ or more 0.895g / cm ³ or less.

In addition, various resins used in the surface layer (A) may be resins using plant-derived raw materials. When it is desired to increase the ratio of plant-derived biomass materials in the laminated film, the content of the biomass polyolefin in the resin component contained in the surface layer (A) is preferably 10% by mass or more, more preferably It is 20 to 50% by mass. On the other hand, when the above-mentioned various properties such as heat-sealability, melt-sealability, and impact resistance are emphasized, it is preferred that the content of the biomass polyolefin in the resin component contained in the surface layer (A) is less than 10 mass. %, More preferably less than 5% by mass, and even more preferably substantially no biomass material.

Various additives may be blended in the surface layer (A) so long as the effect of the present invention is not impaired. Examples of the additive include antioxidant Chemical agents, weathering stabilizers, antistatic agents, anti-fog agents, anti-adhesive agents, slip agents, nucleating agents, pigments, etc.

The surface roughness (Ra) of the surface layer (A) based on JIS B-0601 is preferably 0.2 to 1.0, and more preferably 0.3 to 0.7. By setting the surface roughness to this range, a thin film having excellent surface smoothness can be obtained even if the amount of other components (additives such as a smoothing agent or an anti-adhesive agent) is reduced or they are not used in combination according to the situation. The speed of bag-making is increased, the alignment and bag-making operations after bag-making are improved, and the efficiency is improved. After filling the contents, the workability during packaging by automatic packaging machines is improved.

The friction coefficient (ASTM D-1894) on the surface of the surface layer (A) is preferably 0.05 to 0.7, more preferably 0.07 to 0.6, and still more preferably 0.1 to 0.5. By setting it as this range, it becomes easy to improve the film transportability at the time of packaging, the alignment after bag making, the workability of bagging, etc., and it becomes easy to appropriately suppress the film breakage at the time of restraint by a bread bag clip. The coefficient of friction can be adjusted by appropriately adding additives such as a slip agent and an anti-blocking agent in accordance with the resin component used in the surface layer.

[Intermediate layer (B)]

The intermediate layer (B) of the laminated film of the present invention contains a propylene-based resin and further contains a plant-derived biomass polyethylene (b1) having a melt flow rate of 1.5 g / 10 min or more. By using this intermediate layer, it is possible to obtain a laminated film having good heat-sealability or appropriate melt-sealing properties and appropriate impact resistance or bag breakage resistance in a wide temperature range.

The plant-derived biomass polyethylene (b1) used in the intermediate layer (B) is a polyethylene-based resin produced from plant-derived ethylene using sugar cane, corn, beet, and the like as starting materials. Examples of the biomass polyethylene (b1) include linear low density polyethylene (LLDPE), linear medium density polyethylene (LMDPE), linear high density polyethylene (LHDPE), and low density polyethylene ( LDPE), medium-density polyethylene (MDPE), high-density polyethylene (HDPE), etc., and these can be used alone or in combination of two or more. Among these, a linear low-density polyethylene is particularly preferable. The linear low-density polyethylene preferably has a density of 0.925 g / cm ³ or less, and more preferably 0.920 g / cm ³ or less. By setting the density of the linear low-density polyethylene to be used in the above range, it becomes easy to have both appropriate melt strength, high impact resistance, and bag breakage resistance.

The MFR of the biomass polyethylene (b1) used in the intermediate layer (B) is 1.5 g / 10 min or more. By using the biomass polyethylene of this MFR, even if the content of the biomass polyethylene is increased, excellent melt strength can be achieved in a wide temperature range. The MFR is preferably 1.8 g / 10 min or more, and more preferably 2 g / 10 min or more. The upper limit is not particularly limited, but it is preferably 25 g / 10 min or less, and more preferably 20 g / 10 min or less. By setting it as this range, it becomes easy to obtain appropriate film formability or moldability.

From the viewpoint of having a high environmental load reduction effect, and at the same time, it is easy to obtain appropriate rigidity or impact resistance, suitability for bag-making processing of packaging bags, etc., the plant-derived raw materials in the resin component contained in the intermediate layer (B) The content of the substance polyethylene (b1) is preferably 5 mass% or more, more preferably 8 mass% or more, and still more preferably 10 mass% or more. The upper limit is not particularly limited, but particularly when excellent impact resistance, processing suitability, and the like are obtained, it is preferably 60% by mass or less, more preferably 50% by mass or less, and particularly preferably 40% by mass or less.

Biomass polyethylene (b1) used in the intermediate layer (B) can be produced by using plants such as sugar cane as raw materials to produce monomers, which can be carried out in the same manner as a petroleum-derived production method. The manufacturing method is not particularly limited, and the manufacturer may be a known method. Examples thereof include a manufacturing method using a Ziegler Natta catalyst or a metallocene catalyst.

Specifically, a catalyst system in which a titanium-containing compound itself or a titanium-containing compound is supported on a carrier such as a magnesium compound as a main catalyst, and an organoaluminum compound as a catalyst can be cited. Separately, propylene is added or added. A method for polymerizing a desired α-olefin such as ethylene. This polymerization may be performed by any procedure such as a slurry polymerization method, a solution polymerization method, and a gas phase polymerization method.

In addition, a homogeneous catalyst may be used, and a catalyst including a vanadium compound and an organoaluminum compound that has been used in the past, or one or two cyclopentadienyl groups or substituted cyclopentadienyl groups may also be mentioned. Transition metal compounds such as zirconium, titanium, hafnium, etc. as ligands, indenyl, substituted indenyl, metallocenes such as transition metal compounds that geometrically control the ligands, and catalysts such as alumoxane or ionic compounds Catalysts and other uniform catalyst systems. As the metallocene catalyst, an organoaluminum compound is used as required, and in addition to homogeneous polymerization in the presence of a solvent, any procedure such as a slurry polymerization method and a gas phase polymerization method may be used.

Examples of commercially available products of the aforementioned biomass polyethylene (b1) include SLL218, SLL318, SLH218, SBC818, SPB208, and SEB853 manufactured by Braskem.

In the intermediate layer (B), the biomass polyethylene (b1) may be used in combination with a fossil fuel-derived polyethylene (b2) as a polyethylene-based resin using fossil fuels such as petroleum as a raw material. Examples of the fossil fuel-derived polyethylene (b2) include linear low-density polyethylene (LLDPE), linear medium-density polyethylene (LMDPE), linear high-density polyethylene (LHDPE), and low-density polyethylene. Polyethylene resins such as density polyethylene (LDPE), medium density polyethylene (MDPE), high density polyethylene (HDPE), or ethylene-butene-rubber copolymer (EBR), ethylene-propylene-rubber copolymer (EPR) , Ethylene-vinyl acetate copolymer (EVA), ethylene-methyl methacrylate copolymer (EMMA), ethylene-ethyl acrylate copolymer (EEA), ethylene-methyl acrylate (EMA) copolymer, ethylene-acrylic acid Ethyl-maleic anhydride copolymer (E-EA-MAH), ethylene-acrylic acid copolymer (EAA), ethylene-methacrylic acid copolymer (EMAA) and other ethylene-based copolymers; even ionic polymerization of ethylene-acrylic acid copolymers Materials, ionic polymers of ethylene-methacrylic acid copolymers, etc., and can be used alone or in combination of two or more. Among these, LLDPE, LDPE, and EBR are preferred, and linear low-density polyethylene is particularly preferred. The linear low-density polyethylene preferably has a density of 0.915 g / cm ³ or less, more preferably 0.910 g / cm ³ or less, and even more preferably 0.906 g / cm ³ or less. By setting the density of the linear low-density polyethylene to be used in the above range, it becomes easy to have both appropriate melt strength, high impact resistance, and bag breakage resistance. The linear low-density polyethylene may be used singly or in combination.

The MFR (190 ° C, 21.18N) of the linear low-density polyethylene derived from fossil fuels is preferably 10 g / 10 minutes or less, and more preferably 1 to 5 g / 10 minutes. By setting the MFR to this range, it becomes easy to obtain a thin film that can easily improve the film-forming property of the film, and also has good dispersibility.

When using fossil fuel-derived polyethylene (b2), the origin of the resin component contained in the intermediate layer (B) is derived from the viewpoint of easily obtaining appropriate bag-making suitability, melt-sealing strength, and bag-breaking resistance. The content of the fossil fuel polyethylene (b2) is preferably 3% by mass or more, more preferably 5% by mass or more, even more preferably 8% by mass or more, and particularly preferably 10% by mass or more. The content is preferably 30% by mass or less, more preferably 20% by mass or less, and even more preferably 15% by mass or less.

The propylene-based resin used in the intermediate layer (B) is preferably the same as the propylene-based resin used in the surface layer (A), and exemplified are homopolymers of propylene and propylene-α-olefin copolymers (propylene -α-olefin random copolymer, propylene-α-olefin block copolymer) and the like.

From the viewpoint of easily obtaining appropriate melt strength or bag-making suitability, the content of the propylene-based resin in the resin component contained in the intermediate layer (B) is preferably 10% by mass or more, and more preferably 20% by mass or more. It is more preferably 30% by mass or more. The content is preferably 80% by mass or less, more preferably 70% by mass or less, and even more preferably 60% by mass or less.

When the laminated film of the present invention is formed as a transparent film, as the propylene resin, a propylene homopolymer and a propylene-α-olefin random copolymer can be preferably used. Examples of the propylene-α-olefin random copolymer include a propylene-ethylene copolymer, a propylene-1-butene copolymer, and a propylene-ethylene-1-butene copolymer. These can be used alone or in combination.

The MFR (230 ° C, 21.18N) of the propylene homopolymer is not particularly limited as long as it is a range capable of forming a laminated film, but is preferably 0.5 g / 10 minutes or more, more preferably 2.0 g / 10 minutes or more, and further More preferably, it is 3.0 g / 10 minutes or more. In addition, in order to obtain good moldability, The MFR is preferably 20 g / 10 minutes or less, more preferably 15 g / 10 minutes or less, and even more preferably 10 g / 10 minutes or less.

Propylene homopolymer densities, preferably 0.880g / cm ³ or more 0.920g / cm ³ or less, more preferably 0.885g / cm ³ or more 0.915g / cm ³ or less.

From the viewpoint of further maintaining processing suitability such as bag making, the melting point of the propylene homopolymer is preferably 145 ° C or higher, and more preferably 150 ° C or higher.

As the propylene-based resin, a propylene homopolymer and a propylene-α-olefin random copolymer are preferably used in combination. As the propylene-α-olefin random copolymer, it is preferable to use the same as the surface layer (A), and it is particularly preferable to use a propylene-ethylene copolymer. As the propylene-ethylene copolymer, it is preferable to use the same as the above-mentioned surface layer (A) in the case of forming a transparent film, and preferable ranges of ethylene content, MFR, density, and melting point are also similar to those applicable to the above-mentioned surface layer ( A) The same propylene-ethylene copolymer is used.

When a propylene homopolymer is used as the propylene-based resin, the content of the propylene homopolymer in the resin component contained in the intermediate layer (B) is preferably 35 mass from the viewpoint of easily obtaining appropriate rigidity or transparency. % Or more, more preferably 45% by mass or more, and still more preferably 50% by mass or more. From the viewpoint of easily obtaining appropriate punching strength, it is preferably 85% by mass or less, more preferably 80% by mass or less, and still more preferably 75% by mass or less.

When a propylene-ethylene copolymer is used, the content of the propylene-ethylene copolymer in the resin component contained in the intermediate layer (B) is from the viewpoint of easily obtaining appropriate bag-making suitability or bag-breaking resistance. , Preferably 5 quality The amount is at least%, more preferably at least 10% by mass. The content is preferably 30% by mass or less, and more preferably 25% by mass or less.

The resin component contained in the intermediate layer (B) may be any one of the above-mentioned resins in an appropriate content, but from the viewpoint of easily suppressing deterioration of rigidity and impact strength when the total thickness of the design laminated film is thin, The content of the propylene resin in the resin component contained in the intermediate layer (B) is preferably 55% by mass or more, and the content of the vinyl resin is preferably 5 to 45% by mass. Among them, it is particularly preferable that the content of the propylene homopolymer in the resin component contained in the intermediate layer (B) is 50 to 80% by mass, the propylene-ethylene random copolymer is 5 to 25% by mass, and the source is The total amount of biomass-derived polyethylene (b1) and fossil fuel-derived polyethylene (b2) is 5 to 45% by mass.

When the laminated film of the present invention is formed into a matte film, a propylene-based block copolymer resin is preferably used as the propylene-based resin. As this propylene-based block copolymer resin, it is preferable to use the same thing as the propylene-based block copolymer resin used for the said surface layer (A) when forming a matte film. The propylene-based block copolymer resin may be a single copolymer or a plurality of copolymers.

The content of the propylene-based block copolymer in the resin component contained in the intermediate layer (B) in the case of forming a matte film is preferably 95 mass from the viewpoint of easily obtaining an appropriate impact resistance or matting feeling. % Or less, more preferably 85% by mass or less, even more preferably 80% by mass or less, and particularly preferably 75% by mass or less. Furthermore, from the viewpoint of easily obtaining appropriate stability at the time of bag-making, it is preferably 15% by mass or more, more preferably 20% by mass or more, even more preferably 25% by mass or more, and particularly preferably 30% by mass. Amount above.

In addition, as the resin component contained in the intermediate layer (B), when only the three components of biomass polyethylene (b1), polyethylene (b2) derived from fossil fuel, and propylene-based block copolymer (b3) are used, The content ratio is preferably (biomass polyethylene (b1) / fossil fuel-derived polyethylene (b2) / propylene-based block copolymer (b3)), and the mass ratio is set to 2/3/95 ~ 30/25/45, more preferably 10/5/85 ~ 25/20/55. By setting this ratio, a laminated film having an appropriate matting quality and excellent bag breaking resistance, particularly excellent bag breaking resistance and friction resistance at low temperatures can be obtained.

The block copolymer resin may be used in combination with the olefin-based resin as described above. Among them, a propylene-α-olefin random copolymer is preferably used. As the propylene-α-olefin random copolymer, it is preferable to use the same as the surface layer (A), and it is particularly preferable to use a propylene-ethylene copolymer. As the propylene-ethylene copolymer, it is preferable to use the same as the above-mentioned surface layer (A) in the case of forming a transparent film, and preferable ranges of ethylene content, MFR, density, and melting point are also similar to those applicable to the above-mentioned surface layer ( A) The same propylene-ethylene copolymer is used.

When a propylene-α-olefin random copolymer is used in combination with the block copolymer resin, the content of the propylene-α-olefin random copolymer in the resin component contained in the intermediate layer (B) is preferably 5 Mass% or more, more preferably 15 mass% or more, and still more preferably 25 mass% or more. In addition, it is preferably 50% by mass or less, more preferably 45% by mass or less, and even more preferably 40% by mass or less. By using a propylene-α-olefin random copolymer in this intermediate layer, the bag-breaking resistance can be maintained, and at the same time, more excellent melt-sealing strength can be obtained during bag-making.

The resin component contained in the intermediate layer (B) may be any one of the above-mentioned resins in an appropriate content, but from the viewpoint of easily suppressing deterioration of rigidity and impact strength when the total thickness of the design laminated film is thin, The content of the propylene resin in the resin component contained in the intermediate layer (B) is preferably 55% by mass or more, and the content of the vinyl resin is preferably 7 to 45% by mass. Among them, it is particularly preferable to use a propylene-based block copolymer (b3) and a propylene-ethylene random copolymer as the propylene-based resin, and the total amount of these is 55% by mass or more. The biomass polyethylene (b1) of the plant and the polyethylene (b2) derived from the fossil fuel have a total amount of 7 to 45% by mass.

As the resin component contained in the intermediate layer (B), it is preferable to use only biomass polyethylene (b1), fossil fuel-derived polyethylene (b2), propylene-based block copolymer (b3), and propylene. -Ethylene random copolymer, the content ratio of these (biomass polyethylene (b1) / fossil fuel-derived polyethylene (b2) / propylene-based block copolymer (b3) / propylene-ethylene random copolymer ), With a mass ratio of 2/3/65/30 ~ 25/20/15/40, and more preferably 10/5/50/35 ~ 15/15/30/40. By setting this ratio, a laminated film having an appropriate matting quality and excellent bag breaking resistance, particularly excellent bag breaking resistance and friction resistance at low temperatures can be obtained.

Further, in the intermediate layer (B), additives such as those exemplified in the above-mentioned surface layer may be appropriately used.

[Sealing layer (C)]

The sealing layer (C) used in the present invention is the adhesion between the sealing layers used in the laminated film, or the laminated film and other containers or films. Wait for the next layer. The sealing layer may be appropriately selected as long as it is suitable for the type of use or the object to be sealed. For example, when sealing layers are sealed with each other and used as a packaging bag, from the viewpoint of obtaining an appropriate sealing strength, a propylene-ethylene random copolymer, a propylene-1-butene copolymer, and the like can be suitably used. Sealing layers for α-olefin-propylene copolymers such as propylene-α-olefin copolymers and 1-butene-propylene copolymers. Among them, from the viewpoint of easy adjustment of the heat-sealing temperature or strength during low-temperature easy-opening sealing, and a wide range of heat-sealing temperatures, and easy obtaining of appropriate heat-sealing strength as the easy-opening sealing, propylene-1 is preferred. -Butene-based resins such as butene copolymers and 1-butene-propylene copolymers.

When a propylene-1-butene copolymer or a 1-butene-propylene copolymer is used, it is preferable that the 1-butene content in the copolymer is from the viewpoint of easily obtaining appropriate sealing properties or blocking resistance. 60 to 95 mole%, more preferably 65 to 95 mole%, and even more preferably 70 to 90 mole%. From the viewpoint of easily obtaining suitable low-temperature sealing properties, the propylene content is preferably 2 to 10 mol%, more preferably 3 to 9 mol%, and still more preferably 4 to 8 mol%.

When a butene-based resin such as a propylene-1-butene copolymer or a 1-butene-propylene copolymer is used, the content of the butene-based resin is preferably 50% by mass of the resin component contained in the sealing layer. Hereinafter, it is more preferably 40% by mass or less, and still more preferably 30% by mass or less. Moreover, it is preferable that it is 10 mass% or more, and it is more preferable that it is 15 mass% or more. When the content of the butene-based resin is within this range, it is easy to obtain appropriate low-temperature sealing properties, melt strength or crack resistance of the bag-making product, and it is also advantageous for cost reduction.

As the resin used in combination with the above-mentioned butene-based resin, other polyolefin-based resins can be appropriately used, but from the viewpoint of easily adjusting the seal strength, a propylene-α-olefin copolymer or ethylene-α- is preferably used. As an olefin copolymer, a propylene-α-olefin copolymer is particularly preferred.

The content of the α-olefin in the propylene-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. Examples of the α-olefin include ethylene, 1-hexene, 4-methyl-1-pentene, and 1-octene. Among them, a propylene-ethylene random copolymer exemplified in the above-mentioned intermediate layer is preferably used. From the viewpoint of easily obtaining good moldability, the MFR is preferably 0.5 to 20 g / 10 minutes, and more preferably 2 to 10 g / 10 minutes.

From the viewpoint of easily obtaining suitable low-temperature sealing properties, the content of other olefin-based resins is preferably 90% by mass or less, and more preferably 85% by mass or less in the resin component contained in the sealing layer. Moreover, it is preferable that it is 50 mass% or more, and it is more preferable that it is 60 mass% or more.

In particular, when the laminated film of the present invention is used to form a packaging bag, when an easy-opening portion for heat-sealing the sealing layers is provided, a butene-based resin and a propylene-α-olefin copolymer are preferably used. The butene-based resin / propylene-α-olefin copolymer has a mass ratio of 20/80 to 50/50 and is used in combination.

In addition, various resins used in the sealing layer (C) may be resins using plant-derived raw materials. When it is desired to increase the ratio of the plant-derived biomass material in the laminated film, it is preferable to set the content of the biomass polyolefin in the resin component contained in the sealing layer (C) to 10% by mass or more. It is more preferable to set it as 20-50 mass%. On the other hand, when the above-mentioned various properties such as heat-sealability, melt-sealability, and impact resistance are emphasized, the content of the biomass polyolefin in the resin component contained in the sealing layer (C) is preferably less than 10 mass %, More preferably less than 5% by mass, and even more preferably substantially no biomass material.

Various additives may be blended in the sealing layer (C) as long as the effect of the present invention is not impaired. Examples of the additive include an antioxidant, a weather-resistant stabilizer, an antistatic agent, an anti-fogging agent, an anti-sticking agent, a slip agent, a nucleating agent, and a pigment.

The friction coefficient (ASTM D1894) on the surface of the sealing layer (C) is preferably 0.01 to 0.4, more preferably 0.02 to 0.35, and still more preferably 0.05 to 0.30. By setting it as this range, it becomes easy to improve the film conveyance property at the time of packaging, and the bagging operation by wrinkle or swelling suppression after bag-making. In addition, when filling contents such as bread and the like, it is easy to suppress damage caused by friction between the contents and the inner surface of the film, or to improve abrasion resistance and crack resistance, and it is easy to appropriately suppress film breakage. In addition, the friction coefficient can be adjusted by appropriately adding additives such as a sliding material and an anti-blocking agent in accordance with the resin component used in the sealing layer.

[Laminated film]

The laminated film of the present invention is a laminated film having at least the above-mentioned surface layer (A), intermediate layer (B) and sealing layer (C), and one surface layer of the laminated film is a surface layer, and the other surface layer includes a laminated layer of a sealing layer film. From the viewpoint of having an appropriate melt-sealing strength even in a wide temperature range and being excellent in impact resistance and bag breakage resistance, It can be suitably used as various packaging films.

The thickness of the laminated film of the present invention may be appropriately adjusted in accordance with the application or aspect to be used, but it is preferably from the viewpoint of easily combining volume reduction in packaging applications or bag breakage resistance during distribution. The total thickness is 20 to 60 μm, and more preferably 25 to 50 μm.

The thickness or thickness ratio of each layer is not particularly limited. For example, the thickness of the surface 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 to 10 μm, and more preferably 2 to 8 μm.

From the viewpoint of easily obtaining appropriate melt strength and bag-making suitability, the thickness ratio of the surface layer is preferably 15% or more of the total thickness of the laminated film, and more preferably 20% or more. Moreover, it is preferable that it is 35% or less, and it is more preferable that it is 30% or less. From the viewpoint of easily obtaining appropriate rigidity, melt strength, and bag-making suitability, the thickness ratio of the intermediate layer is preferably 30% or more of the total thickness of the laminated film, and more preferably 40% or more. In addition, it is preferably set to 70% or less, and more preferably set to 65% or less. From the viewpoint of easily obtaining appropriate easy-opening properties, melt strength, and bag-making suitability, the thickness ratio of the sealing layer is preferably 5% to 30% of the total thickness of the laminated film, and more preferably 10 to 25%.

From the viewpoint of reducing the environmental load, the laminated film of the present invention preferably has a content of plant-derived biomass polyethylene in the resin component contained in the entire laminated film of 2% by mass or more, more preferably 3% by mass The above is more preferably 5 mass% or more.

From the viewpoint of easily identifying the contents of the package, the present invention The haze of a bright laminated film is preferably 10% or less, more preferably 5.5% or less, and still more preferably 4.5% or less. When the laminated film of the present invention has the above-mentioned high transparency, it also has suitable packaging suitability, and at the same time, it is difficult to produce broken bags such as tears caused by friction or rubbing of the contents and the film. In order to improve the transparency of the laminated film of the present invention, in each layer, a resin component that increases haze such as a block copolymer is not used, or the content is preferably 10% or less when used. It is preferably set to 5% or less to improve transparency.

The laminated film of the present invention may be laminated with any other resin layer other than the above-mentioned surface layer, intermediate layer, and sealing layer, but the thickness of other resin layers is preferably 20% or less of the total thickness, and it is particularly preferable to include the above. Composition of surface layer, intermediate layer and sealing layer. In this configuration, the intermediate layer may be an intermediate layer of a plurality of layers.

As an example of a specific layer structure, a three-layer structure including a surface layer / intermediate layer / sealing layer provided with an intermediate layer between the surface layer and the sealing layer, or a surface layer / intermediate layer composed of a plurality of intermediate layers may be exemplified The four-layer structure of layer 1 / intermediate layer 2 / sealing layer and the like. Among them, a three-layer structure including a surface layer, an intermediate layer, and a sealing layer is preferably used from the viewpoint of adjusting the characteristics of the film or making the film easy.

The manufacturing method of the laminated film of this invention is not specifically limited, For example, the resin or resin mixture used for each layer is heat-melted by each extruder, and a co-extrusion multilayer die method or Methods such as the feed block method are laminated in a molten state and then formed into a film-like co-extrusion method by using aeration or T-die ‧ chill roll method. Because the thickness ratio of each layer can be adjusted relatively freely, and The multilayer film is excellent in hygiene and excellent in cost performance, so this co-extrusion method is preferred. Since the laminated film obtained by this manufacturing method is a multilayer film having substantially no elongation, secondary forming such as deep drawing forming by vacuum forming can also be performed.

In the surface layer, in order to improve the adhesion with printing ink, etc., it is preferable to perform a surface treatment. Examples of the aforementioned surface treatment include surface oxidation treatments such as corona treatment, plasma treatment, chromic acid treatment, flame treatment, hot air treatment, ozone and ultraviolet treatment, and surface unevenness treatment such as sand blasting. Corona treatment.

Examples of the packaging material containing the laminated film of the present invention include packaging bags, containers, and lid materials for use in food, pharmaceuticals, industrial parts, miscellaneous goods, magazines, and the like. In particular, from the viewpoint of excellent matting feeling that has not been available in the past, packaging materials such as Japanese paper can be provided, and they can be suitably used for foods that give a high-quality feeling.

In the aforementioned packaging bag, the sealing layer of the laminated film of the present invention is preferably used as a heat-sealing layer, and the sealing layers are overlapped with each other and heat-sealed, or the surface layer and the sealing layer are heat-sealed to form the sealing layer as an inner package. bag. For example, by cutting out two sheets of the laminated film to a size necessary for a packaging bag, overlapping them, and heat-sealing three sides into a bag shape, filling the contents from one side without heat-sealing, It is heat-sealed and sealed and used as a packaging bag. In addition, by using an automatic packaging machine, a drum-shaped film can be sealed at the cylindrical end, and then sealed up and down to form a packaging bag.

In addition, when formed into a packaging bag for toast, the printed surface can be folded and sealed to form a packaging bag having a corner portion. Specifically, a bag-making machine, for example, HK-40 manufactured by TOTANI Giken Factory, is used to process the sealing layer of the laminated film according to the present invention to the inside of the bag, and process the bag into a bottom corner bag. The laminated film of the present invention can be suitably used as a bottom corner bag application from the viewpoint of realizing suitable melt strength or bag-making suitability. It is preferable to adjust the melting and sealing temperature or the bag making speed so that the melting and sealing strength of the side portion of the bottom corner bag and the bottom corner portion (the folded portion at the bottom) become 7.5N ~ 30N / 15mm, and preferably 10 ~ 30N / 15mm.

The obtained bottom corner bag is supplied to an automatic toast filling machine. After filling, the toast is heat-sealed under conditions of easy opening and heat-sealing strength of 0.1 to 5 N / 15 mm, preferably 0.2 to 4 N / 15 mm. Easy-opening toast bags, even if needed, can be formed on the upper part of the bag, preferably the upper part of the toast, to form an easy-opening sealing part, or use plastic plates, tapes, ropes and other restraints on the upper part of the bag , Sealed by restraint.

In addition, when forming various kinds of bread such as cream rolls, it is supplied to a horizontal pillow type automatic packaging machine in a roll shape so that the sealing layer becomes the inside of the bag, for example, FW manufactured by Fuji MACHINERY Co., Ltd. -3400αV type and so on. The laminated film of the present invention can be suitably used particularly as a pillow-shaped packaging bag from the viewpoint that the heat-sealing property or the easy-opening property at the time of pillow-shaped packaging is also excellent. The horizontal pillow type automatic packaging machine overlaps the heat cover of the film and heat-seals to form a bag, and at the same time, the bread is contained. At this time, it is preferable to adjust the heat-sealing temperature or packaging speed so that the sealing strength of the bottom of the pillow-shaped packaging bag and the backing portion using the packaging machine becomes 7.5N-30N / 15mm, and preferably 8-20N / 15mm. then, It can also be heat-sealed with easy opening and heat sealing strength of 0.1 ~ 5N / 15mm, preferably 0.2 ~ 4N / 15mm to form an easy-to-open sealing portion, and it can also be used in the vicinity of plastic plates, tapes, ropes, etc. The restraint is bound.

In addition, a packaging bag, a container, and a container lid can be formed by superimposing a sealing film and a heat-sealable different film and heat-sealing. At this time, as the different films to be used, films such as LDPE, EVA, and polypropylene having weaker mechanical strength can be used. In addition, LDPE, EVA, polypropylene, and other films can be used, and stretch films with relatively good tear properties can be used, such as biaxially stretched polyethylene terephthalate film (OPET) and biaxially stretched polypropylene films. (OPP) laminated film.

As described above, the laminated film of the present invention can be suitably applied to various packaging applications from the viewpoint of achieving appropriate impact resistance or bag breakage resistance. In particular, from the viewpoint of achieving excellent shock resistance at low temperatures, it is suitable for food packaging applications that are often packaged or distributed at low temperatures.

Among them, the laminated film of the present invention is difficult to produce broken bags at the time of binding when it is applied to bread packaging such as toast or sweet bread using a binding device (bread bag clip) having a sharp front end portion or a hook portion. When contact with the tether or transport container occurs during transportation, pinholes or tears are not easy to occur. In addition, pinholes or tears caused by friction, stabbing, etc. of a plastic tray rubbing or mixing the inner surface (sealing surface) of the film with the contents are not easy to occur. Furthermore, the laminated film of the present invention is particularly suitable for use in bread packaging applications from the viewpoint of ensuring an appropriate melt-sealing strength when forming the chamfered portion.

[Example]

Next, examples and comparative examples will be given to explain the present invention in more detail. Unless otherwise specified below, "parts" and "%" are quality standards.

(Example 1)

As the resin component forming each of the surface layer, the intermediate layer, and the sealing layer, the following resins were used, respectively, and the resin mixture forming each layer was adjusted. Each of these mixtures was supplied to three extrusion machines and co-extruded so that the average thickness of each layer of the laminated film formed of the surface layer, the intermediate layer, and the sealing layer was 7/18/5 μm, and a laminated layer having a thickness of 30 μm was formed. film. Next, a corona discharge treatment was performed on the surface layer of the obtained laminated film to obtain a surface energy of 33 mN / m to obtain a laminated film.

Surface layer: Contains a propylene-ethylene copolymer (ethylene content: 2%, density: 0.90 g / cm ³ , melt index (hereinafter referred to as MI.): 6 g / 10 minutes, melting point 140 ° C.) (hereinafter referred to as COPP (1 ).) 55 parts by mass, 35 parts by mass of propylene-ethylene-1-butene terpolymer (density: 0.90 g / cm ³ , MFR: 5.4 g / 10 min (190 ° C, 21.18 N)), and crystallinity 10 parts by mass of an ethylene-1-butene copolymer (density: 0.88 g / cm ³ , MI: 4 g / 10 minutes)

Intermediate layer: propylene homopolymer (density: 0.90 g / cm ³ , MFR: 7.5 g / 10 minutes) (hereinafter referred to as HOPP (1).) 65 parts by mass, propylene-ethylene copolymer (ethylene content: 5.2%, Density: 0.90 g / cm ³ , MFR: 5.4 g / 10 minutes) (hereinafter referred to as COPP (2).) 10 parts by mass, linear low-density polyethylene (density: 0.905 g / cm ³ , MFRI: 4.0 g / 10 minutes) (hereinafter referred to as LLDPE (1).) 15 parts by mass, and a sugarcane-derived linear low-density polyethylene-based resin of biochemical polyethylene, Braskem SLL318 (density: 0.918 g / cm ³ , MFR = 2.7 g / 10 minutes) (hereinafter referred to as biochemical PE (1).) 10 parts by mass of a resin mixture

Sealing layer: 70 parts by mass of COPP (2), 1-butene-propylene copolymer (density: 0.90 g / cm ³ , MFR (measurement temperature 230 ° C): 4 g / 10 minutes) 30 parts by mass

(Example 2)

Except that the resin component of the resin mixture used for the intermediate layer was the following, it carried out similarly to Example 1, and obtained the laminated film.

Intermediate layer: 65 parts by mass of HOPP (1), 10 parts by mass of COPP (2), 15 parts by mass of LLDPE (1), and a sugarcane-derived linear low-density polyethylene-based resin of biochemical polyethylene, Braskem Corporation SLH218 ( Density: 0.916 g / cm ³ , MFR = 2.3 g / 10 minutes) (hereinafter referred to as biochemical PE (2).) 10 parts by mass

(Example 3)

Except that the resin component of the resin mixture used for the intermediate layer was the following, it carried out similarly to Example 1, and obtained the laminated film.

Middle layer: 60 parts by mass of HOPP (1), 15 parts by mass of COPP (2), 10 parts by mass of LLDPE (1), 15 parts by mass of biochemical PE (1)

(Example 4)

Set the resin content of the resin mixture used in the intermediate layer to Other than that, it carried out similarly to Example 1, and obtained the laminated film.

Middle layer: 55 parts by mass of HOPP (1), 20 parts by mass of COPP (2), 10 parts by mass of LLDPE (1), and 15 parts by mass of biochemical PE (2)

(Example 5)

The resin components of the resin mixture used in the surface layer and the intermediate layer were set as follows, and co-extrusion was performed so that the average thickness of each layer of the laminated film formed by the surface layer / intermediate layer / seal layer was 7/18/5 μm Except that, it carried out similarly to Example 1, and formed the laminated film.

Surface layer: 100 parts by mass of a propylene-ethylene block copolymer (density: 0.90 g / cm ³ , MI: 8 g / 10 minutes, melting point 160 ° C.) (hereinafter referred to as a propylene-based block copolymer (1))

Intermediate layer: 35 parts by mass of COPP (2), a propylene-ethylene block copolymer (density: 0.90 g / cm ³ , MI: 6 g / 10 minutes, melting point 160 ° C.) (hereinafter referred to as a propylene-based block copolymer (2 )) 40 parts by mass, 10 parts by mass of LLDPE (1), 15 parts by mass of biochemical PE (1)

(Example 6)

Except that the resin component of the resin mixture used for the intermediate layer was the following, it carried out similarly to Example 5, and obtained the laminated film.

Middle layer: 35 parts by mass of COPP (2), 40 parts by mass of propylene-based block copolymer (2), 10 parts by mass of LLDPE (1), and 15 parts by mass of biochemical PE (2)

(Example 7)

Set the resin content of the resin mixture used in the intermediate layer to Other than that, it carried out similarly to Example 5, and obtained the laminated film.

Intermediate layer: 35 parts by mass of COPP (2), 35 parts by mass of propylene-based block copolymer (2), 10 parts by mass of LLDPE (1), and 20 parts by mass of biochemical PE (1)

(Example 8)

Except that the resin component of the resin mixture used for the intermediate layer was the following, it carried out similarly to Example 5, and obtained the laminated film.

Intermediate layer: 35 parts by mass of COPP (2), 40 parts by mass of propylene-based block copolymer (2), 5 parts by mass of LLDPE (1), and 20 parts by mass of biochemical PE (2)

(Comparative example 1)

Except that the resin component of the resin mixture used for the intermediate layer was the following, it carried out similarly to Example 1, and obtained the laminated film.

Intermediate layer: 65 parts by mass of HOPP (1), 10 parts by mass of COPP (2), 15 parts by mass of LLDPE (1), and a sugarcane-derived linear low-density polyethylene-based resin of biochemical polyethylene, Braskem SLL118 ( Density: 0.918 g / cm ³ , MFR = 1.0 g / 10 minutes) (hereinafter referred to as biochemical PE (3).) 10 parts by mass

(Comparative example 2)

Except that the resin component of the resin mixture used for the intermediate layer was the following, it carried out similarly to Example 1, and obtained the laminated film.

Middle layer: 60 parts by mass of HOPP (1), 15 parts by mass of COPP (2), 10 parts by mass of LLDPE (1), 15 parts by mass of biochemical PE (3)

(Comparative example 3)

Except that the resin component of the resin mixture used for the intermediate layer was the following, it carried out similarly to Example 5, and obtained the laminated film.

Intermediate layer: 35 parts by mass of COPP (2), 40 parts by mass of propylene-based block copolymer (2), 10 parts by mass of LLDPE (1), and 15 parts by mass of biochemical PE (3)

(Comparative Example 4)

Except that the resin component of the resin mixture used for the intermediate layer was the following, it carried out similarly to Example 5, and obtained the laminated film.

Intermediate layer: 35 parts by mass of COPP (2), 35 parts by mass of propylene-based block copolymer (2), 10 parts by mass of LLDPE (1), and 20 parts by mass of biochemical PE (3)

(Reference example 1)

Except that the resin component of the resin mixture used for the intermediate layer was the following, it carried out similarly to Example 1, and obtained the laminated film.

Middle layer: 75 parts by mass of HOPP (1), 15 parts by mass of COPP (2), and 10 parts by mass of LLDPE (1)

Using the laminated films obtained in the above examples and comparative examples, the following tests and evaluations were performed. The results obtained are described in the following table.

[Measurement of rigidity]

The 1% tangent modulus (unit: MPa) at 23 ° C of the films obtained in the examples and comparative examples was measured using a Tensilon tensile tester [manufactured by A & D Co., Ltd.] based on ASTM D-882. Measurement system The extrusion direction (hereinafter referred to as "MD") and the film width direction (hereinafter referred to as "CD") during film production are carried out.

◎: Rigidity is 600 MPa or more

○: Rigidity is 550 MPa or more and less than 600 MPa

△: Rigidity is 450 or more and less than 550 MPa

×: Rigidity is less than 450MPa

[Bag-making suitability evaluation]

The sealing layer of the films obtained in the examples and comparative examples was made into the inside, and after the film was halved, a corner was added to the bottom, and the sealing was performed at a sealing temperature (bag-making temperature) of 300 ° C, and a bag-making was performed (bag-making machine: TOTANI Technical Research HK-40 manufactured by the factory (stock), bag making speed: 120 sheets / minute, bottom corner bag (length: 345 mm (side portion: 245 mm, corner portion: 60 mm), width 235 mm) was produced, and the bag making suitability was evaluated. In addition, 300 sheets were grouped into one group, aligned and bundled, and the alignment was evaluated.

○: Even at a bag making speed of 120shots, the film can be followed, and alignment is not a problem

△: Even at a bag making speed of 120shots, the film can be followed, but some alignment is a problem

×: At a bag making speed of 120shots, there are followers who cannot follow, poor alignment

[Melting strength]

Using the films obtained in the examples and comparative examples, the same evaluation as the above-mentioned bag-making suitability was performed to produce a bottom corner bag. Self-obtained bottom gusset bag 5 Ten pieces of 70 mm in length and 15 mm in width were cut out from the center of the chamfered portion on both sides of the sheet and the center of the side portions other than the chamfered portion. The speed was 300 mm / minute, and the maximum load at the time of tension by a Tensilon tensile tester (manufactured by A & D (strand)) was used as the melt strength. In the range of 260 ° C to 360 ° C, the sealing temperature (bag-making temperature) for melting and sealing was changed every 20 ° C, and the same measurement was performed.

◎: The melting strength of the chamfered part and the side part is 16N / 15mm or more

○: The melting strength of the chamfered part and the side part is 15N / 15mm or more and less than 16N / 15mm

○ △: The melting strength of the chamfered part and the side part are both 14.5N / 15mm or more 1. Less than 15N / 15mm

△: The melting strength of the chamfered part and the side part is 13N / 15mm or more and less than 14.5N / 15mm

×: The melting strength of at least one of the chamfered portion and the side portion is less than 13N / 15mm

[Heat seal strength]

Using the films obtained in the examples and comparative examples, the same evaluation as the above-mentioned bag-making suitability was performed to produce a bottom corner bag. A 50 mm portion from the upper end of the opening portion of the obtained bottom gusset bag to the lower portion was parallel to the opening portion, and a heat sealer (manufactured by TESTER SANGYO Co., Ltd .: pressure 0.2 MPa, time 1 second, sealing temperature: 95 ° C of the upper sealing rod) , Lower seal rod 50 ° C, seal rod shape: 300m × 10mm plane) for heat sealing. Self-obtained 5 pieces of heat-sealed parts of the gusset bag, 2 pieces at a time, 10 pieces of test pieces with a length of 70 mm and a width of 15 mm were cut out respectively, and the heat-sealed parts became the central part in the width direction. In minutes, the maximum load at the time of peeling using a Tensilon tensile tester (manufactured by A & D (strand)) was taken as the heat seal strength.

○: The heat seal strength is less than 5N / 15mm, and the film does not crack during peeling

×: The heat-sealing strength is 5N / 15mm or more, or the film is cracked during peeling

[Determination of impact strength]

The films obtained in the examples and comparative examples were held in a constant temperature room at 0 ° C. for 6 hours, and then a 1.5-inch spherical metal punch was used to measure the impact strength by the film punch method.

◎: Impact strength is 0.20 or more

○: Impact strength is 0.15 (J) or more and less than 0.20

△: Impact strength is 0.1 (J) or more and less than 0.15

×: Impact strength is less than 0.1 (J)

It is obvious from the above table that the laminated films of the present invention of Examples 1 to 8 are those having appropriate sealing strength, impact resistance, and good melt sealing strength in a wide temperature range. On the other hand, the laminated films of Comparative Examples 1 to 4 are those in which it is difficult to obtain good melt-sealing strength in a wide temperature range.

Claims (14)

A laminated film is a laminated film comprising a surface layer (A), an intermediate layer (B) and a sealing layer (C), which is characterized in that the surface layer (A), the intermediate layer (B) and the sealing layer (C) ) Contains a propylene-based resin, and the intermediate layer (B) contains a plant-derived biomass polyethylene (b1), and a melt flow rate of the biomass polyethylene (b1) is 1.5 g / 10 min or more. The laminated film according to claim 1, wherein the biomass polyethylene (b1) is a linear low-density polyethylene. For example, the laminated film of claim 1 or 2, wherein the content of the biomass polyethylene (b1) in the resin component contained in the intermediate layer (B) is 15% by mass or more. The laminated film according to any one of claims 1 to 3, wherein the intermediate layer (B) contains a propylene-ethylene copolymer resin in an amount of 5 mass% or more of the resin components contained in the intermediate layer (B) as the propylene-based resin. The laminated film according to any one of claims 1 to 4, wherein the surface layer (A) contains 50% by mass or more of a propylene-ethylene random copolymer resin in a resin component contained in the surface layer (A). The laminated film according to claim 5, wherein the intermediate layer (B) contains 30% by mass or more of a propylene homopolymer in a resin component contained in the intermediate layer (B). The laminated film according to any one of claims 1 to 4, wherein the surface layer (A) contains 50% by mass or more of a propylene-based block copolymer resin among the resin components contained in the surface layer (A). The laminated film of claim 7, wherein the intermediate layer (B) contains an intermediate layer 15% by mass or more of the propylene-based block copolymer resin in the resin component contained in (B). The laminated film according to any one of claims 1 to 8, wherein the sealing layer (C) contains a propylene-ethylene copolymer resin and a butene-based resin. The laminated film according to any one of claims 1 to 9, wherein the intermediate layer (B) contains 3% by mass or more of polyethylene (b2) derived from a fossil fuel in a resin component contained in the intermediate layer (B). For example, the laminated film of claim 10, wherein the melt flow rate of the polyethylene (b2) derived from fossil fuel is 3 to 10 g / 10 min. A food packaging bag using a laminated film according to any one of claims 1 to 11. The food packaging bag according to claim 12, which has a chamfered portion. The food packaging bag of claim 12 or 13 is used for bread packaging.