WO2019131168A1 - 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 a plant-derived material.

In recent years, for the purpose of reducing environmental impact, we will consider replacing some of the raw materials of resin films used for packaging materials with resins mainly composed of plant-derived components, from resins mainly composed of fossil fuel-derived components such as petroleum Is being done.

As a resin film using a plant-derived resin, for example, a sealant film using a plant-derived linear low density polyethylene as a sealant film to be laminated on a substrate and used for a laminate tube or a standing pouch (Patent Document 1 And (2), and a lid (patent document 3) and the like provided with a sealant layer using a plant-derived low density biomass polyethylene and a base material.

JP, 2016-145086, A JP 2012-167172 A JP, 2015-231870, A

Plant-derived resins often exhibit properties that are highly environmentally compatible but differ from fossil fuel-derived resins, and simply replacing them could reduce heat sealability, impact resistance, bag resistance, etc. . However, although the resin film disclosed in the above document uses a plant-derived resin, when it is applied to applications such as standing pouches and lids, lamination with a laminate base is performed. The impact resistance and the tear resistance, etc., in the film configuration having no laminate substrate are not considered at all.

In addition, in the case of forming a packaging bag by melt-cut sealing, it is necessary to have melt-cut sealability to be applied to various packaging forms, and to realize suitable sealability under manufacturing conditions according to various uses. It is desirable to have good melt seal strength over a wide temperature range.

Although the resin film disclosed in the above document is mainly composed of an ethylene-based resin, it is desirable to replace a fossil fuel-derived resin with a plant-derived resin also in a film configuration mainly composed of a propylene-based resin. It is rare.

The problem to be solved by the present invention is that, in a film structure mainly composed of a propylene-based resin, it has suitable seal strength and impact resistance while applying a plant-derived component, and a good melt-cut seal in a wide temperature range An object of the present invention is to provide a laminated film having strength.

In particular, to provide a laminated film having suitable seal strength and impact resistance even when containing a large amount of plant-derived components, and further, applying a resin-plant-derived component in a film structure mainly composed of a propylene-based resin At the same time, it is an object of the present invention to provide a laminated film capable of achieving suitable seal strength and impact resistance without using a laminate substrate.

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

The laminated film of the present invention is suitably used as various packaging materials because it has suitable seal strength and impact resistance while having resin derived from plants, and has good fused seal strength over a wide temperature range. it can. In particular, since it has excellent impact resistance even when the laminate base is not laminated, it can be suitably used as a packaging bag for pillow packaging and gusset packaging. In particular, since the laminated film of the present invention is excellent in melting strength, it is suitable for use as a gusset packaging bag used for packaging food such as bread.

The laminated film of the present invention has at least a surface layer (A), an intermediate layer (B) and a seal layer (C), one surface layer comprising the surface layer (A) and the other surface layer comprising the seal layer (C) It is a laminated film and contains propylene-based resin in the surface layer (A), the intermediate layer (B) and the seal layer (C), and the intermediate layer (B) contains plant-derived biomass polyethylene (b1), the biomass The melt flow rate of polyethylene (b1) is a laminated film of 1.5 [g / 10 min] or more.

[Surface layer (A)]
The surface layer (A) used for the laminated film of the present invention is a layer constituting a surface layer such as a layer on which printing of a packaging film is provided. The 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) etc. can be used.

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 70% by mass or more because it is easy to obtain suitable melting strength and bag-making suitability. The content is more preferably 80% by mass or more, and still more preferably 85% by mass or more. In addition, the resin component contained in the surface layer (A) may be a surface layer substantially consisting of only a propylene-based 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. In addition, the α-olefin content is preferably 2% by mass or more, more preferably 3% by mass or more, and still more preferably 4% by mass or more, since suitable impact resistance can be easily obtained. .

When making the laminated film of the present invention into a transparent film, a propylene-α-olefin random copolymer can be preferably used as a propylene-based resin used for the surface layer (A). Examples of the propylene-α-olefin random copolymer include propylene-ethylene random copolymer, propylene-1-butene random copolymer, propylene-ethylene-1-butene random copolymer and the like, and these can be used alone. It may be used or may be used in combination. Among them, a propylene-ethylene random copolymer can be preferably used because it is easy to obtain suitable transparency.

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 it is preferably 0.5 g / 10 min or more, and 3 g / 10 min or more. Is more preferable, and 5 g / 10 min or more is more preferable. Further, in order to obtain good moldability, the MFR is preferably 20 g / 10 min or less, more preferably 15 g / 10 min or less, and more preferably 12 g / 10 min or less.

Propylene - density of the ethylene random copolymer, more it is preferably at most 0.880 g / cm ³ or more 0.905 g / cm ^3, is 0.890 g / cm ³ or more 0.900 g / cm ³ or less preferable.

The melting point of the propylene-ethylene random copolymer is preferably 110 ° C. or more, and more preferably 115 ° C. or more, from the viewpoint of preventing adhesion to the fused cutting blade during bag making. In addition, since sufficient fusion cutting ball formation is necessary in order to develop fusion cutting seal strength at the time of fusion cutting sealing at the time of bag making, the temperature is preferably 150 ° C. or less, more preferably 145 ° C. or less.

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 because it is easy to obtain suitable transparency and packaging suitability. The content is preferably 35% by mass or more, more preferably 45% by mass or more, and still 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.

In addition, since it is easy to form sufficient fused balls at the time of fused sealing, a random copolymer such as a propylene-1-butene copolymer or a propylene-ethylene-1-butene copolymer, which has a lower melting point, is used as the above-mentioned propylene. It is also preferred to use in combination with an ethylene random copolymer. Among them, propylene-ethylene-1-butene copolymer can be particularly preferably used.

As the propylene-ethylene-1-butene copolymer, the ethylene content and butene content of the propylene-ethylene-1-butene copolymer are each preferably 25% by mass or less, and 15% by mass or less Is more preferably 10% by mass. In addition, 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 3% by mass, since it is easy to obtain suitable low-temperature sealability. It is more preferable that it is more than.

The melt flow rate (MFR) of the propylene-ethylene-1-butene copolymer is not particularly limited as long as it can form a laminated film, but is preferably 0.5 g / 10 min or more, 3.0 g / minute. It is more preferable that it is 10 minutes or more, and it is more preferable that it is 5.0 g / 10 minutes or more. Further, in order to obtain good moldability, the MFR is preferably 20 g / 10 min or less, more preferably 15 g / 10 min or less, and more preferably 12 g / 10 min or less.

Propylene - ethylene-density butene copolymer is preferably not more than 0.880 g / cm ³ or more 0.905 g / cm ^3, is 0.890 g / cm ³ or more 0.900 g / cm ³ or less Is more preferred.

The melting point of the propylene-ethylene-1-butene copolymer is preferably 105 ° C. or more, and more preferably 110 ° C. or more, from the viewpoint of preventing adhesion to the fusion cutting seal blade during bag-making. In addition, it is preferable that the temperature is 145 ° C. or less, and more preferably 140 ° C. or less, because it is necessary to form sufficient fused and broken balls in order to develop fused and sealed strength when fused and sealed at the time of bag making.

When using a propylene-ethylene-1-butene copolymer, the content of the propylene-ethylene-1-butene copolymer in the resin component contained in the surface layer is that it is easy to obtain a suitable melt-cut seal strength Therefore, the content is preferably 15% by mass or more, more preferably 25% by mass or more, and still more preferably 30% by mass or more. 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 using the laminated film of the present invention as a matte film, a propylene-based block copolymer resin, particularly a propylene-α-olefin block copolymer, is used as a propylene-based resin used for the surface layer (A). It can be used preferably. Examples of the α-olefin include ethylene, 1-butene, 1-hexene, 4-methyl 1-pentene, 1-octene and the like. Among them, ethylene is preferable because it is excellent in the balance of matte feeling, cold resistance and rigidity.

The melt flow rate (MFR) of the propylene-based block copolymer resin is preferably 0.5 g / 10 min or more because it is easy to mold and to obtain suitable impact resistance and matte feeling. More preferably, it is 1 g / 10 min or more. Moreover, it is preferable that it is 20 g / 10 minutes or less, and it is more preferable that it is 10 g / 10 minutes or less.

The melting point of the propylene-based block copolymer resin is preferably 155 ° C. or more, and preferably 165 ° C. or less, because it is easy to obtain a suitable bag-making property.

The propylene block copolymer resin used for the surface layer (A) may use a single copolymer or a plurality of copolymers. When using two or more, it is preferable to make the total of content of the propylene-type block copolymer resin to be used into the following range.

As a propylene-based block copolymer resin which is used in the surface layer (A) and is excellent in the balance with the matte feeling, melting strength and bag-making suitability, BC8, BC7 (manufactured by Japan Polypropylene Corporation), E150GK, F704V (prime) Polymer Co., Ltd.), PC480A, PC684S, PC380A, VB370A (manufactured by Sun Aroma Co., Ltd.), and the like.

In the case of using a propylene-based block copolymer resin as the propylene-based resin, the content of the propylene-based block copolymer in the resin component contained in the surface layer (A) has a matte feeling, melting strength and bag-making ability. The balance may be appropriately adjusted, but it is preferably contained in an amount of 50% by mass or more, more preferably 70% by mass or more in the resin component used for the surface layer (A). By setting it as the said range, it becomes easy to acquire the matte feeling which was excellent in the designability and which has uniformity. Among them, when making impact resistance high, it is preferable to set it to 80 to 100% by mass, and when improving matte feeling, it is preferable to set it to 70 to 90% by mass.

Moreover, in the surface layer (A), various olefin resins used for packaging films other than the above-mentioned propylene resin may be used. Examples of the olefin resin other than the propylene resin include polyethylene resins such as ultra low density polyethylene (VLDPE), linear low density polyethylene (LLDPE), low density polyethylene (LDPE), and ethylene-1-butene copolymer. , Ethylene-vinyl acetate copolymer (EVA), ethylene-methyl methacrylate copolymer (EMMA), ethylene-ethyl acrylate copolymer (EEA), ethylene-methyl acrylate (EMA) copolymer, ethylene-ethyl acrylate -Ethylene-based copolymers such as maleic anhydride copolymer (E-EA-MAH), ethylene-acrylic acid copolymer (EAA), ethylene-methacrylic acid copolymer (EMAA), etc .; further ethylene-acrylic acid Copolymer ionomer, ethylene-methacrylic acid copolymer Ionomer and the like can be used. When using olefin resin other than these propylene resin, it is preferable that content of the said olefin resin in the resin component contained in surface layer (A) is 20 mass% or less.

In the present invention, among these olefin resins, they have flexibility in a wide temperature range which is effective at the time of bag making, and good dispersibility with propylene resins can be obtained. It can be used preferably. The said copolymer can be especially preferably used, when setting it as a transparent film. In the case of using the ethylene-1-butene copolymer, the content of the ethylene-1-butene copolymer in the resin component contained in the surface layer is 1 to 1 because it is easy to obtain a suitable low temperature seal. The content is preferably 20% by mass, and more preferably 5 to 15% by mass.

The MFR (230 ° C., 21.18 N) of the ethylene-1-butene copolymer is not particularly limited as long as it can form a laminated film, but is preferably 0.5 g / 10 min or more, 2.0 g It is more preferable that it is / 10 minutes or more, and it is more preferable that it is 3.0 g / 10 minutes or more. Further, in order to obtain good moldability, the MFR is preferably 20 g / 10 min or less, more preferably 15 g / 10 min or less, and more preferably 10 g / 10 min or less.

The density of the ethylene-1-butene copolymer, it is preferably at most 0.870 g / cm ³ or more 0.900 g / cm ^3, is 0.875 g / cm ³ or more 0.895 g / cm ³ or less More preferable.

Moreover, you may use resin which used the plant origin raw material for various resin used in surface layer (A). When it is desired to increase the plant-derived biomass material ratio in the laminated film, the content of biomass polyolefin in the resin component contained in the surface layer (A) is preferably 10% by mass or more, and 20 to 50% by mass It is more preferable to On the other hand, when importance is placed on the above various properties such as heat sealability, melt-cut sealability and impact resistance, the content of biomass polyolefin in the resin component contained in the surface layer (A) should be less than 10% by mass. Is preferable, and it is preferably less than 5% by mass, and it is also preferable to contain substantially no biomass material.

In the surface layer (A), various additives may be blended as long as the effects of the present invention are not impaired. Examples of the additive include an antioxidant, a weathering stabilizer, an antistatic agent, an antifogging agent, an antiblocking agent, a lubricant, a nucleating agent, a pigment and the like.

The surface roughness (Ra) of the surface layer (A) according to JIS B-0601 is preferably 0.2 to 1.0, and more preferably 0.3 to 0.7. By making surface roughness into the said range, the addition amount of other components (additives, such as a slip agent and an antiblocking agent) is reduced, or even if it does not use together in some cases, the film which is excellent in surface slipperiness is As a result, it is possible to improve the bag-making speed, to improve the packing efficiency after packing, to improve the efficiency of the packing operation, and to improve the workability when the contents are filled and then packaged by an automatic packaging machine or the like.

The coefficient of friction (ASTM D-1894) of the surface layer (A) surface is preferably 0.05 to 0.7, more preferably 0.07 to 0.6, and more preferably 0.1 to 0.5. Within this range, it is easy to improve the film feedability at the time of packaging, the attachment uniformity after bag making, the packaging workability and the like, and it becomes easy to preferably suppress the film breakage at the time of binding by the closure. The coefficient of friction can be adjusted by appropriately adding additives such as lubricants and antiblocking agents according to the resin component used for the surface layer.

[Intermediate layer (B)]
The intermediate layer (B) of the laminated film of the present invention is a layer containing a propylene-based resin, and further containing plant-derived biomass polyethylene (b1) having a melt flow rate of 1.5 g / 10 min or more. By using the said intermediate | middle layer, the laminated | multilayer film which has suitable impact resistance and tear resistance can be obtained with the favorable heat sealability and the suitable fusion | melting sealability in a wide temperature range.

The plant-derived biomass polyethylene (b1) used for the intermediate layer (B) is a polyethylene-based resin produced from plant-derived ethylene which uses sugar cane, corn, beet etc. as a starting material. Examples of the biomass polyethylene (b1) include linear low density polyethylene (LLDPE), linear medium density polyethylene (LMDPE), linear high density polyethylene (LHDPE), low density polyethylene (LDPE), medium density polyethylene (MDPE) And high density polyethylene (HDPE) etc. These may be used alone or in combination of two or more. Among these, linear low density polyethylene is particularly preferable. The linear low density Porieren, preferably density of 0.925 g / cm ³ or less, 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-mentioned range, it becomes easy to combine suitable melting strength, high impact resistance, and resistance to breakage.

The MFR of biomass polyethylene (b1) used for the intermediate layer (B) is 1.5 g / 10 min or more. By using the biomass polyethylene of the said MFR, even if it increases content of biomass polyethylene, the outstanding melting strength can be implement | 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 is preferably 25 g / 10 min or less, and more preferably 20 g / 10 min or less. By setting it as the said range, it becomes easy to acquire suitable film forming property and a moldability.

The content of plant-derived biomass polyethylene (b1) in the resin component contained in the intermediate layer (B) has a high environmental load reduction effect, while making suitable rigidity and impact resistance, bag processing as a packaging bag It is preferable that the content is 5% by mass or more, more preferably 8% by mass or more, and more preferably 10% by mass or more, because the suitability and the like can be easily obtained. The upper limit is not particularly limited, but in order to obtain particularly excellent impact resistance, processability and the like, it is preferably 60% by mass or less, more preferably 50% by mass or less, and 40% by mass or less Is particularly preferred.

The biomass polyethylene (b1) used for the intermediate layer (B) is produced as a monomer by using a plant such as sugar cane as a raw material and can be produced in the same manner as the petroleum-derived production method. There is no restriction | limiting in particular as a manufacturing method, It can be manufactured by a well-known method. For example, preparation methods using a Ziegler-Natta catalyst or a metallocene catalyst can be mentioned.

Specifically, a catalyst system using a titanium-containing compound itself or one having a titanium-containing compound supported on a carrier such as a magnesium compound as a main catalyst and a cocatalyst with an organoaluminum compound, propylene alone or a desired ethylene such as α Mention may be made of the method of polymerization with addition of an olefin. This polymerization may be any process such as slurry polymerization, solution polymerization, gas phase polymerization and the like.

In addition, a homogeneous catalyst may be used, and a catalyst comprising a vanadium compound and an organoaluminum compound conventionally used, or a cyclopentadienyl group, a substituted cyclopentadienyl group, an indenyl group, a substituted indenyl group, etc. Metallocene system consisting of transition metal compounds such as zirconium, titanium and hafnium having one or two ligands, transition metal compounds wherein the ligand is geometrically controlled and cocatalysts such as aluminoxane and ionic compounds Mention may also be made of homogeneous catalyst systems, such as catalysts. The metallocene catalyst may be any process such as a slurry polymerization method or a gas phase polymerization method in addition to homogeneous polymerization in the presence of a solvent, using an organic aluminum compound if necessary.

Examples of commercial products of such biomass polyethylene (b1) include SLL 218, SLL 318, SLH 218, SBC 818, SPB 208, SEB 853 and the like manufactured by Blaschem.

In the middle layer (B), the biomass polyethylene (b1) may be used in combination with polyethylene (b2) derived from fossil fuel, which is a polyethylene-based resin made from fossil fuel such as petroleum. As the polyethylene (b2) derived from the fossil fuel, linear low density polyethylene (LLDPE), linear medium density polyethylene (LMDPE), linear high density polyethylene (LHDPE), low density polyethylene (LDPE), medium Polyethylene resins such as high density polyethylene (MDPE) and high density polyethylene (HDPE), 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-ethyl acrylate-maleic anhydride copolymer (E) -EA-MAH), ethylene-acrylic acid copolymer Ethylene-based copolymers such as EAA), ethylene-methacrylic acid copolymer (EMAA), etc .; furthermore, ionomers of ethylene-acrylic acid copolymers, ionomers of ethylene-methacrylic acid copolymers, etc. , You may mix and use two or more types. Among these, LLDPE, LDPE and EBR are preferable, and linear low density polyethylene is particularly preferable. The linear low density Porieren, preferably density of 0.915 g / cm ³ or less, more preferably 0.910 g / cm ³ or less, still be at 0.906 g / cm ³ or less preferable. By setting the density of the linear low density polyethylene to be used in the above-mentioned range, it becomes easy to combine suitable melting strength, high impact resistance, and resistance to breakage. The linear low density polyethylene may be used alone or in combination of two or more.

The MFR (190 ° C., 21.18 N) of the linear low density polyethylene derived from fossil fuel is preferably 10 g / 10 min or less, more preferably 1 to 5 g / 10 min. By making MFR into the said range, the film-formability of a film is easy to be improved, and dispersibility is also favorable, and it becomes easy to obtain a uniform film.

When using a fossil fuel-derived polyethylene (b2), the content of the fossil fuel-derived polyethylene (b2) in the resin component contained in the intermediate layer (B) is a suitable bag-making aptitude or a melt-cut seal strength and The content is preferably 3% by mass or more, more preferably 5% by mass or more, still more preferably 8% by mass or more, and 10% by mass or more, since it is easy to obtain the bag resistance. Is particularly preferred. The content is preferably 30% by mass or less, more preferably 20% by mass or less, and still more preferably 15% by mass or less.

As the propylene-based resin used for the intermediate layer (B), the same one as the propylene-based resin used for the surface layer (A) can be preferably used, and a homopolymer of propylene, a propylene-α-olefin copolymer (propylene And α-olefin random copolymers, propylene-α-olefin block copolymers) and the like can be exemplified.

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 20% by mass or more, because it is easy to obtain suitable melting strength and bag-making suitability. It is more preferable that it is 30 mass% or more. Moreover, it is preferable that it is 80 mass% or less, It is more preferable that it is 70 mass% or less, It is more preferable that it is 60 mass% or less.

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

MFR (230 ° C., 21.18 N) of propylene homopolymer is not particularly limited as long as it can form a laminated film, but it is preferably 0.5 g / 10 min or more, and 2.0 g / 10 min or more Is more preferably 3.0 g / 10 min or more. Further, in order to obtain good moldability, the MFR is preferably 20 g / 10 min or less, more preferably 15 g / 10 min or less, and more preferably 10 g / 10 min or less.

The density of the propylene homopolymer is preferably from 0.880 g / cm ³ or more 0.920 g / cm ^3, more preferably at most 0.885 g / cm ³ or more 0.915 g / cm ^3.

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

In addition, it is also preferable to use a propylene homopolymer and a propylene-α-olefin random copolymer in combination as the propylene-based resin. As the propylene-α-olefin random copolymer, those similar to the above surface layer (A) can be preferably used, and in particular, a propylene-ethylene copolymer can be preferably used. As the said propylene-ethylene copolymer, the thing similar to the said surface layer (A) at the time of setting it as a transparent film can preferably be used, and preferable ranges, such as ethylene content, MFR, density, and melting point, are also the said surface layer (A). It is similar to the propylene-ethylene copolymer which can be used in

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 35% by mass because it is easy to obtain suitable rigidity and transparency. It is preferable that it is more than, 45 mass% or more is more preferable, and 50 mass% or more is more preferable. In addition, it is preferably 85% by mass or less, more preferably 80% by mass or less, and still more preferably 75% by mass or less because a suitable impact strength can be easily obtained.

In addition, when a propylene-ethylene copolymer is used, the content of the propylene-ethylene copolymer in the resinous portion contained in the intermediate layer (B) is suitable for bag-making aptitude and tear resistance. In order to obtain easily, it is preferable that it is 5 mass% or more, and it is more preferable that it is 10 mass% or more. Moreover, it is preferable that it is 30 mass% or less, and it is more preferable that it is 25 mass% or less.

As the resin component contained in the intermediate layer (B), the above-mentioned various resins may be used at an appropriate content, but it is easy to suppress the deterioration of the rigidity and impact strength when designing the total thickness of the laminated film thin. Therefore, the content of the propylene-based resin in the resin component contained in the intermediate layer (B) is preferably 55% by mass or more, and the content of the ethylene-based resin is preferably 5 to 45% by mass. Above all, the content of 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 plant-derived biomass polyethylene ( It is particularly preferable to adjust the total amount of b1) and the fossil fuel-derived polyethylene (b2) to 5 to 45% by mass.

When using the laminated film of the present invention as a matte film, a propylene-based block copolymer resin can be preferably used as the propylene-based resin. As the said propylene-type block copolymer resin, the thing similar to propylene-type block copolymer resin used for the said surface layer (A) at the time of setting it as a matte film can be used preferably. The propylene block copolymer resin may use 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) when forming a matte film is 95% by mass or less because it is easy to obtain suitable impact resistance and matte feeling Is more preferably 85% by mass or less, still more preferably 80% by mass or less, and particularly preferably 75% by mass or less. In addition, the content is preferably 15% by mass or more, more preferably 20% by mass or more, and still more preferably 25% by mass or more, since it is easy to obtain suitable bag making stability. % Or more is particularly preferred.

Moreover, when using only three components of biomass polyethylene (b1), polyethylene (b2) derived from fossil fuel and propylene-based block copolymer (b3) as resin components contained in the intermediate layer (B), The ratio of the content of biomass (biomass polyethylene (b1) / polyethylene (b2) derived from fossil fuel / propylene block copolymer (b3)) is 2/3/95 to 30/25/45 by mass ratio Is more preferably 10/5/85 to 25/20/55. By setting the ratio, it is possible to obtain a laminate film having excellent bag-proof resistance, in particular, excellent bag-proof resistance and abrasion resistance at low temperatures, while having a suitable matte tone.

In addition, an olefin resin as described above may be used in combination with the block copolymer resin, and among these, a propylene-α-olefin random copolymer can be preferably used. As the propylene-α-olefin random copolymer, those similar to the above surface layer (A) can be preferably used, and in particular, a propylene-ethylene copolymer can be preferably used. As the said propylene-ethylene copolymer, the thing similar to the said surface layer (A) at the time of setting it as a transparent film can preferably be used, and preferable ranges, such as ethylene content, MFR, density, and melting point, are also the said surface layer (A). It is similar to the propylene-ethylene copolymer which can be used in

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) The amount is preferably 5% by mass or more, more preferably 15% by mass or more, and still more preferably 25% by mass or more. The content is preferably 50% by mass or less, more preferably 45% by mass or less, and still more preferably 40% by mass or less. By using a propylene-α-olefin random copolymer for the intermediate layer, it is possible to obtain a better blowout seal strength at the time of bag making while maintaining the bag-proof resistance.

As the resin component contained in the intermediate layer (B), the above-mentioned various resins may be used at an appropriate content, but it is easy to suppress the deterioration of the rigidity and impact strength when designing the total thickness of the laminated film thin. Therefore, it is preferable to set the content of the propylene-based resin in the resin component contained in the intermediate layer (B) to 55% by mass or more, and the content of the ethylene-based resin to 7 to 45% by mass. Above all, using propylene-based block copolymer (b3) and propylene-ethylene random copolymer as the propylene-based resin, the total amount of these is 55 mass% or more, and plant-derived biomass as the ethylene-based resin It is particularly preferred to use polyethylene (b1) and polyethylene derived from fossil fuel (b2) to a total amount of 7 to 45% by mass.

Furthermore, only biomass polyethylene (b1), polyethylene (b2) derived from fossil fuel, propylene-based block copolymer (b3) and propylene-ethylene random copolymer are used as resin components contained in the intermediate layer (B) Ratio of these contents (biomass polyethylene (b1) / polyethylene (b2) derived from fossil fuel / propylene block copolymer (b3) / propylene-ethylene random copolymer) is 2/3 / mass ratio It is preferably 65/30 to 25/20/15/40, and more preferably 10/5/50/35 to 15/15/30/40. By setting the ratio, it is possible to obtain a laminate film having excellent bag-proof resistance, in particular, excellent bag-proof resistance and abrasion resistance at low temperatures, while having a suitable matte tone.

In the intermediate layer (B), additives as exemplified in the surface layer may be appropriately used.

[Seal layer (C)]
The seal layer (C) used in the present invention is a layer used for adhesion of the seal layers of the laminated film, and adhesion of the laminated film to another container, film or the like. As the sealing layer, a resin type that can obtain a suitable sealing strength may be appropriately selected according to the use mode and the object to be sealed. For example, when sealing layers are sealed to be used as a packaging bag, propylene-α- such as propylene-ethylene random copolymer, propylene-1-butene copolymer and the like from the viewpoint of obtaining appropriate seal strength. A seal layer containing an α-olefin-propylene copolymer such as an olefin copolymer or a 1-butene-propylene copolymer can be suitably used. Above all, it is easy to adjust the heat seal temperature and strength at the time of easy opening seal at low temperature, the heat seal temperature range is wide, and it is easy to obtain appropriate heat seal strength as the easy opening seal. Polymers or butene resins such as 1-butene-propylene copolymer are preferred.

In the case of using a propylene-1-butene copolymer or a 1-butene-propylene copolymer, the 1-butene content in the copolymer is 60 because it is easy to obtain suitable sealability and blocking resistance. It is preferably ~ 95 mol%, more preferably 65-95%, still more preferably 70-90 mol%. In addition, the propylene content is preferably 2 to 10 mol%, more preferably 3 to 9 mol%, and still more preferably 4 to 8 mol%, since it is easy to obtain suitable low-temperature sealability. preferable.

In the case of using a butene-based resin such as a propylene-1-butene copolymer or a 1-butene-propylene copolymer, the content of the butene-based resin is 50% by mass or less in the resin component contained in the seal layer It is preferable to set it as 40 mass% or less, It is more preferable to set it as 30 mass% or less. Moreover, it is preferable to be 10 mass% or more, and it is more preferable to be 15 mass% or more. When the content of the butene-based resin is in the above range, it is easy to obtain suitable low-temperature sealability, melting strength and tear resistance of bag-formed products, and it is also advantageous for cost reduction.

As the resin used in combination with the butene-based resin, other polyolefin-based resins can be appropriately used. However, since it is easy to adjust the seal strength suitably, a propylene-α-olefin copolymer or an ethylene-α-olefin copolymer is used. Coalescing can be preferably used, and propylene-α-olefin copolymer can be particularly preferably used.

The content of the α-olefin in the propylene-α-olefin copolymer is not particularly limited, but is preferably 1 to 20% by mass, and more preferably 1.5 to 15% by mass. Examples of α-olefins include ethylene, 1-hexene, 4-methyl-1-pentene, 1-octene and the like. Among them, a propylene-ethylene random copolymer as exemplified in the above-mentioned intermediate layer can be preferably used. The MFR is preferably 0.5 to 20 g / 10 min, and more preferably 2 to 10 g / 10 min, because it is easy to obtain good moldability.

The content of the other olefin resin is preferably 90% by mass or less, and more preferably 85% by mass or less, in the resin component contained in the seal layer, because it is easy to obtain suitable low-temperature sealability. . Moreover, it is preferable to set it as 50 mass% or more, and it is more preferable to set it as 60 mass% or more.

In particular, when forming a packaging bag using the laminated film of the present invention, in the case of providing an easy-to-open portion in which seal layers are heat-sealed together, a butene-based resin and a propylene-α-olefin copolymer, It is preferable to use together in a ratio that the mass ratio represented by butene resin / propylene-α-olefin copolymer is 20/80 to 50/50.

Moreover, you may use the resin which used the plant origin raw material for various resin used in a sealing layer (C). When it is desired to increase the plant-derived biomass material ratio in the laminated film, the content of biomass polyolefin in the resin component contained in the seal layer (C) is preferably 10% by mass or more, and 20 to 50% by mass It is more preferable to On the other hand, when importance is placed on the above various properties such as heat sealability, melt-cut sealability, and impact resistance, the content of biomass polyolefin in the resin component contained in the seal layer (C) should be less than 10% by mass. Is preferable, and it is preferably less than 5% by mass, and it is also preferable to contain substantially no biomass material.

In the seal layer (C), various additives may be blended as long as the effects of the present invention are not impaired. Examples of the additive include an antioxidant, a weathering stabilizer, an antistatic agent, an antifogging agent, an antiblocking agent, a lubricant, a nucleating agent, a pigment and the like.

The coefficient of friction (ASTM D1894) of the surface of the seal 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 the said range, it becomes easy to improve the packing operation | work by the film feedability at the time of packaging, and the wrinkles and buildup suppression after bag making. Moreover, suppression of the damage | wound by abrasion with the content and the film inner surface at the time of filling contents, such as bread, and abrasion resistance and anti-tear property improvement improve easily, and it becomes easy to suppress a film tear suitably. The coefficient of friction can be adjusted by appropriately adding additives such as lubricants and antiblocking agents according to the resin component used for the seal layer.

[Laminated film]
The laminate film of the present invention is a laminate film having at least the surface layer (A), the intermediate layer (B) and the seal layer (C), one surface layer of the laminate film is a surface layer, and the other surface layer is It is a laminated film which consists of a seal layer. The laminated film of the said structure has suitable fusion | melting cutting seal strength also in a wide temperature range, and since it is excellent in impact resistance and tear resistance, it can be used suitably as a film for various packaging.

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

The thickness and thickness ratio of each layer are not particularly limited, but 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 seal layer is preferably 1 to 10 μm, more preferably 2 to 8 μm.

Further, 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, because it is easy to obtain suitable melting strength and bag-making suitability. Moreover, it is preferable to set it as 35% or less, and it is more preferable to set it as 30% or less. 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, because it is easy to obtain suitable rigidity, melting strength, and bag-making suitability. Further, the content is preferably 70% or less, more preferably 65% or less. 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%, because it is easy to obtain suitable easy openability, melting strength and bag-making suitability.

In the laminated film of the present invention, the content of plant-derived biomass polyethylene in the resin component contained in the entire laminated film is preferably 2% by mass or more, and 3% by mass or more from the viewpoint of environmental load reduction. Is more preferable, and 5% by mass or more is more preferable.

The haze of the laminated film of the present invention is preferably 10% or less, more preferably 5.5% or less, and preferably 4.5% or less, because the content to be packaged is easily visible. Is more preferred. Even when the laminated film of the present invention has such high transparency, it has a suitable packaging aptitude, but is less likely to be broken due to a friction between the contents and the film or a tear due to rubbing. In order to increase the transparency of the laminated film of the present invention, in each layer, a resin component for increasing the haze, such as a block copolymer, is not used, or the content is preferably 10% even when used. The transparency can be improved by setting the content to 5% or less, more preferably.

The laminated film of the present invention may be laminated with any other resin layer other than the surface layer, the intermediate layer and the seal layer, but the thickness of the other resin layer is 20% or less of the total thickness. The structure comprising the surface layer, the intermediate layer and the seal layer is particularly preferable. In addition, in the said structure, the intermediate layer on which the intermediate layer was laminated in multiple numbers may be sufficient.

Specific examples of the layer configuration include a three-layer configuration of surface layer / intermediate layer / seal layer in which an intermediate layer is provided between the surface layer and the seal layer, or a surface layer in which the intermediate layer is composed of a plurality of layers A four-layer structure of / intermediate layer 1 / intermediate layer 2 / seal layer, etc. can be preferably exemplified. Among them, a three-layer structure consisting of a surface layer / intermediate layer / seal layer can be preferably used because adjustment of the film properties and production of the film are easy.

The method for producing the laminated film of the present invention is not particularly limited. For example, the resin or resin mixture used for each layer is heated and melted by separate extruders, and the method such as coextrusion multilayer die method or feed block method After laminating in a molten state, a coextrusion method of forming into a film by inflation, T-die / chill roll method or the like may be mentioned. This co-extrusion method is preferable because the ratio of the thickness of each layer can be adjusted relatively freely, and a multilayer film excellent in hygiene and cost performance can be obtained. Since the laminated film obtained by the said manufacturing method is obtained as a substantially non-stretching multilayer film, secondary formation, such as deep draw forming by vacuum forming, is also attained.

It is also preferable to apply a surface treatment to the surface layer in order to improve the adhesion to the printing ink and the like. Examples of such surface treatment include surface oxidation treatment such as corona treatment, plasma treatment, chromic acid treatment, flame treatment, hot air treatment, ozone / ultraviolet treatment and the like, and surface unevenness treatment such as sand blast and the like. Preferably it is a corona treatment.

As a packaging material which consists of laminated | multilayer film of this invention, the packaging bag used for applications, such as foodstuffs, medicine, industrial parts, miscellaneous goods, a magazine, a container, the lid material of a container, etc. are mentioned. In particular, a packaging material similar to Japanese paper and the like can be provided because it has an excellent matte feeling and is superior to conventional ones, and can be suitably used for food and the like used to bring out a high-class feeling.

The packaging bag has the seal layer of the present invention as a heat seal layer, and the seal layers are stacked one on another and heat sealed, or the surface layer and the seal layer are laminated and heat sealed to make the seal layer inside. It is preferable that it is a formed packaging bag. For example, two laminated films are cut out to the size of a desired packaging bag, and they are stacked and heat sealed on three sides to form a bag, and then the contents are filled from one side which is not heat sealed. It can be used as a packaging bag by heat sealing and sealing. Furthermore, it is also possible to form a packaging bag by sealing the top and bottom of the rolled film in a cylindrical shape after sealing the rolled film with an automatic packaging machine.

Moreover, when setting it as the packaging bag for breads, it can be set as the packaging bag which has a gusset part by folding and sealing a printing surface. Specifically, it is processed into a bottom gusset bag by a bag making machine such as HK-40 manufactured by Totani Giken Kogyo Co., Ltd. so that the seal layer of the laminated film of the present invention is on the inside of the bag. The laminated film of the present invention can be particularly suitably used as a bottom gusset bag application because it can realize suitable melt-cutting strength and bag-making suitability. Adjusting the melting and sealing temperature and the bag-making speed so that the melting and sealing strength of the bottom gusset bag's side and bottom gusset (folded bottom) is 7.5 N to 30 N / 15 mm, preferably 10 to 30 N / 15 mm. Is preferred.

The bottom gusset bag obtained is supplied to an automatic bread filling machine, and after being filled with the bread filling, it is easy to open and has a heat seal strength of 0.1 to 5 N / 15 mm, preferably 0.2 to 4 N / 15 mm. Heat-sealed with an easy-open bread packaging bag, and if necessary, forming an easy-open seal portion on the top of the bag, preferably on the top of the bread, or forming the top of the bag with a plastic plate, tape, string, etc. It may be sealed by binding using a binding device.

In addition, when packing and packaging various breads such as butter roll etc., the sealing layer should be on the inside of the bag in a horizontal pillow type automatic packing machine, such as FW-3400 αV made by Fuji Kikai Co., Ltd. Supplied in roll form. The laminated film of the present invention is excellent in heat sealability and easy openability at the time of pillow packaging, and therefore, can be particularly suitably used for a pillow packaging bag. In the horizontal pillow type automatic packaging machine, the heat sealing surface of the film is overlapped and heat sealed to form a bag, and the pan is contained. At this time, it is preferable to adjust the heat sealing temperature and the packaging speed so that the seal strength of the bottom portion and the back attachment portion of the pillow packaging bag by the packaging machine is 7.5N to 30N / 15 mm, preferably 8 to 20N / 15 mm. . Next, the easily openable seal portion may be formed by heat sealing under the condition that the easy opening property and the heat seal strength are 0.1 to 5 N / 15 mm, preferably 0.2 to 4 N / 15 mm, and the vicinity thereof May be bound using a tie such as a plastic plate, tape, or string.

It is also possible to form the lid of the packaging bag / container / container by overlapping and heat sealing the sealing layer and another heat-sealable film. At that time, as another film to be used, films of relatively weak mechanical strength such as LDPE, EVA, polypropylene and the like can be used. In addition, laminated films in which films of LDPE, EVA, polypropylene, etc., and stretched films with relatively good tearability, such as biaxially stretched polyethylene terephthalate film (OPET), biaxially stretched polypropylene film (OPP), etc., are also used. It can be used.

As mentioned above, since the laminated film of the present invention can realize suitable impact resistance and tear resistance, it can be suitably applied to various packaging applications. In particular, since excellent impact resistance can be realized even at low temperatures, it is suitable for food packaging applications where packaging and distribution are often performed at low temperatures.

Among them, when the laminated film of the present invention is applied to bread packaging such as bread and confectionery bread in which a binding tool (closure) having a sharp tip portion or a heel portion is used, a break in bag is hardly generated. In addition, pinholes and tears are less likely to occur when contact with the tie or transport container occurs during transfer. Moreover, it is hard to produce a pinhole and a tear by friction with the food which is the contents, and the film inner surface (seal surface), rubbing with the plastic tray mixed, and piercing. Furthermore, the laminated film of the present invention can be particularly suitably applied to bread packaging applications because it can ensure a suitable melt-sealed seal strength even when the gusset portion is formed.

Next, the present invention will be described in more detail by way of examples and comparative examples. Hereinafter, “parts” and “%” are on a mass basis unless otherwise noted.

Example 1
The following resin was used as a resin component which forms each layer of a surface layer, an intermediate | middle layer, and a sealing layer, and the resin mixture which forms each layer was adjusted. These mixtures are respectively fed to three extruders and coextruded so that the average thickness of each layer of the laminated film formed of the surface layer / interlayer / seal layer is 7/18/5 μm, A 30 μm laminated film was formed. Subsequently, the corona discharge treatment was performed to the surface layer of the obtained laminated film so that surface energy might be 33 mN / m, and the laminated film was obtained.

Surface layer: Propylene-ethylene copolymer (ethylene content: 2%, density: 0.90 g / cm ³ , melt index (hereinafter referred to as MI): 6 g / 10 min, melting point 140 ° C.) (hereinafter, COPP (1) 55 parts by weight) and propylene-ethylene-1-butene terpolymer (density: 0.90 g / cm ³ , MFR: 5.4 g / 10 min (190 ° C., 21.18 N)) Mixture of 35 parts by mass and 10 parts by mass of crystalline ethylene-1-butene copolymer (density: 0.88 g / cm ³ , MI: 4 g / 10 min) Intermediate layer: Propylene homopolymer (density: 0) .90 g / cm ³ , MFR: 7.5 g / 10 min (hereinafter referred to as HOPP (1)) 65 parts by mass, and a propylene-ethylene copolymer (ethylene content: 5.2%, density: 0. 90 g / cm ³ , MFR: 5.4 g / 10 min (hereinafter referred to as COPP (2)) and 10 parts by mass of linear low density polyethylene (density: 0.905 g / cm ³ , MFRI: 4.0 g / 10 min) (Hereinafter referred to as LLDPE (1)) 15 parts by mass, and Braskem SLL 318 (a density: 0.918 g / cm ³ , MFR = 2.7 g) of a linear low density polyethylene resin derived from sugar cane which is a biopolyethylene / 10 minutes) (hereinafter referred to as bioPE (1)) 10 parts by weight of a resin mixture Seal layer: 70 parts by weight 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)
A laminated film was obtained in the same manner as in Example 1 except that the resin component of the resin mixture used for the intermediate layer was changed to the following.
Intermediate layer: 65 parts by mass of HOPP (1), 10 parts by mass of COPP (2), 15 parts by mass of LLDPE (1), Brakem SLH 218 (density: 0. 10 parts by mass of 916 g / cm ³ , MFR = 2.3 g / 10 min (hereinafter referred to as bioPE (2))

(Example 3)
A laminated film was obtained in the same manner as in Example 1 except that the resin component of the resin mixture used for the intermediate layer was changed to the following.
Middle layer: HOPP (1) 60 parts by mass, COPP (2) 15 parts by mass, LLDPE (1) 10 parts by mass, bio-PE (1) 15 parts by mass

(Example 4)
A laminated film was obtained in the same manner as in Example 1 except that the resin component of the resin mixture used for the intermediate layer was changed to the following.
Middle layer: HOPP (1) 55 parts by mass, COPP (2) 20 parts by mass, LLDPE (1) 10 parts by mass, bio PE (2) 15 parts by mass

(Example 5)
The resin component of the resin mixture used for the surface layer and the intermediate layer is as follows, and co-extrusion so that the average thickness of each layer of the laminated film formed of the surface layer / interlayer / seal layer is 7/18/5 μm A laminated film was formed in the same manner as in Example 1 except for the above.
Surface layer: Propylene-ethylene block copolymer (density: 0.90 g / cm ³ , MI: 8 g / 10 min, melting point 160 ° C.) (hereinafter referred to as propylene-based block copolymer (1)) 100 parts by mass Intermediate Layer: 35 parts by mass of COPP (2), propylene-ethylene block copolymer (density: 0.90 g / cm ³ , MI: 6 g / 10 min, melting point 160 ° C.) (hereinafter, propylene-based block copolymer (2) ) 40 parts by weight, LLDPE (1) 10 parts by weight, bio PE (1) 15 parts by weight

(Example 6)
A laminated film was obtained in the same manner as in Example 5 except that the resin component of the resin mixture used for the intermediate layer was changed to the following.
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), 15 parts by mass of bio-PE (2)

(Example 7)
A laminated film was obtained in the same manner as in Example 5 except that the resin component of the resin mixture used for the intermediate layer was changed to the following.
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), 20 parts by mass of bio-PE (1)

(Example 8)
A laminated film was obtained in the same manner as in Example 5 except that the resin component of the resin mixture used for the intermediate layer was changed to the following.
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), 20 parts by mass of bio-PE (2)

(Comparative example 1)
A laminated film was obtained in the same manner as in Example 1 except that the resin component of the resin mixture used for the intermediate layer was changed to the following.
Intermediate layer: 65 parts by mass of HOPP (1), 10 parts by mass of COPP (2), 15 parts by mass of LLDPE (1), Braskem SLL 118 (density: 0. 10 parts by mass of 918 g / cm ³ , MFR = 1.0 g / 10 min (hereinafter referred to as bioPE (3))

(Comparative example 2)
A laminated film was obtained in the same manner as in Example 1 except that the resin component of the resin mixture used for the intermediate layer was changed to the following.
Intermediate 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 bioPE (3)

(Comparative example 3)
A laminated film was obtained in the same manner as in Example 5 except that the resin component of the resin mixture used for the intermediate layer was changed to the following.
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), 15 parts by mass of bio-PE (3)

(Comparative example 4)
A laminated film was obtained in the same manner as in Example 5 except that the resin component of the resin mixture used for the intermediate layer was changed to the following.
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), 20 parts by mass of bio-PE (3)

(Reference Example 1)
A laminated film was obtained in the same manner as in Example 1 except that the resin component of the resin mixture used for the intermediate layer was changed to the following.
Intermediate layer: 75 parts by mass of HOPP (1), 15 parts by mass of COPP (2), 10 parts by mass of LLDPE (1)

The following test and evaluation were performed using the laminated film obtained by said Example and comparative example. The results obtained are shown in the table below.

[Measurement of stiffness]
The 1% tangential modulus (unit: MPa) at 23 ° C. of the films obtained in Examples and Comparative Examples is measured using a Tensilon tensile tester (manufactured by A & D Co., Ltd.) based on ASTM D-882. It was measured. The measurement was performed in the extrusion direction (hereinafter referred to as "MD") and the film width direction (hereinafter referred to as "CD") at the time of film production.
:: rigidity is 600 MPa or more ○: rigidity is 550 MPa or more and less than 600 MPa Δ: rigidity is 450 or more and less than 550 MPa ×: rigidity is less than 450 MPa

[Bag making aptitude evaluation]
After half-folding the film with the seal layer of the film obtained in the example and the comparative example inside, put a gusset in the bottom part and seal by melting at a sealing temperature (bag-making temperature) of 300 ° C to make a bag (bag making Machine: HK-40 manufactured by Totani Giken Co., Ltd., bag making speed: 120 sheets / min, and a bottom gusset bag (vertical: 345 mm (side: 245 mm, gusset: 60 mm), 235 mm wide) is manufactured. The bag making suitability was evaluated. Moreover, 300 sheets were made into 1 set, and it was put together and put together as a bundle, and the put togetherness was evaluated.
○: The film follows at a bag-making speed of 120 shots, and there is no problem with the alignment. Δ: The film follows at a bag-making speed of 120 shots, but the alignment with a part becomes a problem. ×: 120 shots There are things that can not keep up with the bag speed, and the alignment is bad

Melt strength
A bottom gusset bag was produced in the same manner as the above-mentioned bag making suitability evaluation using the films obtained in Examples and Comparative Examples. Test pieces of 70 mm in length and 15 mm in width are respectively from the center of the gusset on both sides of the obtained bottom gusset bag and the center of the side other than the gusset so that the fused seal part becomes the center in the length direction Ten sheets were cut out each, and the maximum load at the time of pulling with a Tensilon tensile tester (manufactured by A & D Co., Ltd.) at 23 ° C. and a tensile speed of 300 mm / min was measured as the melting strength. The same measurement was carried out by changing the seal temperature (the bag-making temperature) of the blowout seal in the range of 260 ° C. to 360 ° C. every 20 ° C.
:: The melting strength of the gusset portion and the side portion is 16 N / 15 mm or more for all ○: The melting strength of the gusset portion and the side portion is 15 N / 15 mm to 16 N / 15 mm for all ○ い ず れ: the melting strength of the gusset portion and the side portion 14.5 N / 15 mm or more and 15 N / 15 mm or less Δ: The melting strength of both the gusset portion and the side portion is 13 N / 15 mm or more and less than 14.5 N / 15 mm ×: The melting strength of at least one of the gusset portion and the side portion is 13 N Less than 15 mm

Heat seal strength
A bottom gusset bag was produced in the same manner as the above-mentioned bag making suitability evaluation using the films obtained in Examples and Comparative Examples. A heat sealer (manufactured by Tester Sangyo Co., Ltd .: 50 mm from the upper end of the bottom bottom of the bottom gusset bag and parallel to the bottom of the bottom gusset bag: pressure 0.2 MPa, time 1 second, seal temperature: upper seal bar 95 ° C., The lower seal bar was heat sealed at 50 ° C., seal bar shape: 300 m × 10 mm flat surface). Test pieces of 70 mm in length and 15 mm in width are cut out from each of the obtained two bottom gusset bags, 10 sheets each at 23 ° C. so that the heat seal part is at the center in the width direction. The maximum load at the time of peeling off with a Tensilon tensile tester (manufactured by A & D Co., Ltd.) at a tensile speed of 300 mm / min was measured as the heat seal strength.
:: Heat seal strength is less than 5 N / 15 mm, no film breakage when peeled off. ×: Heat seal strength is 5 N / 15 mm or more, or film tear when peeled.

[Measurement of impact strength]
The films obtained in Examples and Comparative Examples are held for 6 hours in a temperature-controlled room adjusted to 0 ° C., and then impact strength according to the film impact method using a spherical metallic impact head having a diameter of 1.5 inches Was measured.
:: Impact strength is 0.20 or more ○: Impact strength is 0.15 (J) or more and less than 0.20 Δ: Impact strength is 0.1 (J) or more and less than 0.15 ×: Impact strength is 0.1 ( J) less than

As apparent from the above table, the laminated films of the present invention of Examples 1 to 8 have suitable seal strength, impact resistance, and good melt-sealed seal strength over a wide temperature range. . On the other hand, in the laminated films of Comparative Examples 1 to 4, it was difficult to obtain good fused seal strength in a wide temperature range.

Claims (14)

1. A laminated film in which a surface layer (A), an intermediate layer (B) and a seal layer (C) are laminated,
   The surface layer (A), the intermediate layer (B) and the seal layer (C) contain a propylene-based resin,
   The intermediate layer (B) contains plant-derived biomass polyethylene (b1),
   The melt flow rate of the biomass polyethylene (b1) is 1.5 g / 10 min or more.
2. The laminated film according to claim 1, wherein the biomass polyethylene (b1) is linear low density polyethylene.
3. The laminated film according to claim 1 or 2, wherein the content of biomass polyethylene (b1) in the resin component contained in the intermediate layer (B) is 15% by mass or more.
4. The said intermediate | middle layer (B) is 5 mass% or more in any one of the resin components contained in a middle class (B) in propylene- ethylene copolymer resin as a propylene-type resin. Laminated film.
5. 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).
6. The laminated film according to claim 5, wherein the intermediate layer (B) contains a propylene homopolymer in an amount of 30% by mass or more in a resin component contained in the intermediate layer (B).
7. The laminated film according to any one of claims 1 to 4, wherein the surface layer (A) contains 50% by mass or more of the propylene-based block copolymer resin in the resin component contained in the surface layer (A).
8. The laminated film according to claim 7, wherein the intermediate layer (B) contains a propylene-based block copolymer resin in an amount of 15% by mass or more in the resin component contained in the intermediate layer (B).
9. The laminated film according to any one of claims 1 to 8, wherein the seal layer (C) contains a propylene-ethylene copolymer resin and a butene resin.
10. The laminated film according to any one of claims 1 to 9, wherein the intermediate layer (B) contains polyethylene (b2) derived from fossil fuel in an amount of 3% by mass or more in a resin component contained in the intermediate layer (B).
11. The laminated film according to claim 10, wherein the melt flow rate of the fossil fuel-derived polyethylene (b2) is 3 to 10 g / 10 min.
12. A food packaging bag using the laminated film according to any one of claims 1 to 11.
13. The food packaging bag according to claim 12 having a gusset portion.
14. The food packaging bag according to claim 12 or 13, which is used for bread packaging.