WO2018163835A1

WO2018163835A1 - Laminated film and food packaging bag

Info

Publication number: WO2018163835A1
Application number: PCT/JP2018/006387
Authority: WO
Inventors: 渡辺　康史; 賢人庄司; 松原　弘明
Original assignee: Dic株式会社
Priority date: 2017-03-07
Filing date: 2018-02-22
Publication date: 2018-09-13
Also published as: TW201834862A; JPWO2018163835A1; JP7140104B2

Abstract

This laminated film has at least a surface layer (A), an intermediate layer (B), and a seal layer (C), wherein one outer layer of the laminated film is the surface layer (A) and the other outer layer of the laminated film is the seal layer (C). In this laminated film, the surface layer (A) and the seal layer (C) each contains a propylene-based resin; and the intermediate layer(B) contains a plant-derived biomass polyethylene(b1), a petroleum-derived polyethylene(b2) and a propylene-based block copolymer resin. This laminated film enables suitable sealing strength or impact resistance to be achieved while using a resin plant-derived component.

Description

Laminated film and food packaging bag

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

In recent years, with the aim of reducing environmental impact, some of the raw materials for resin films used in packaging materials have been replaced with resins mainly composed of components derived from fossil fuels such as petroleum, with resins mainly composed of plant-derived components. Has been made.

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 that is laminated with a base material and used for a laminate tube or a standing pouch (Patent Document 1) 2), and a cover material (Patent Document 3) provided with a sealant layer and a base material using plant-derived low-density biomass polyethylene.

Japanese Patent Laid-Open No. 2016-145086 JP 2012-167172 A Japanese Patent Laying-Open No. 2015-231870

Plant-derived resins are highly environmentally friendly, but often exhibit properties different from those derived from fossil fuels. If simply replaced, heat sealability, impact resistance, bag-breaking resistance, etc. may be reduced. . In addition, the resin film disclosed in the above document uses a plant-derived resin, but when applied to uses such as a standing pouch and a lid, it is laminated with a laminate base material. No consideration is given to impact resistance, bag breakage resistance and the like in a film configuration without a laminate substrate.

The resin film disclosed in the above document is mainly composed of an ethylene-based resin. However, even in a film configuration mainly composed of a propylene-based resin, replacement of a fossil fuel-derived resin with a plant-derived resin is desired. It is rare.

The problem to be solved by the present invention is to provide a laminated film having suitable seal strength and impact resistance while applying a resin plant-derived component in a film structure mainly composed of a propylene resin.

Furthermore, in a film configuration mainly composed of propylene-based resin, it is to provide a laminated film that can realize suitable seal strength and impact resistance without using a laminate base material while applying plant-derived components. .

The present invention is a laminated film in which a surface layer (A), an intermediate layer (B) and a seal layer (C) are laminated, wherein the surface layer (A), the intermediate layer (B) and the seal layer (C) Contains a propylene-based resin, and the intermediate layer (B) solves the above problems by a laminated film containing plant-derived biomass polyethylene (b1) and fossil fuel-derived polyethylene (b2).

The laminated film of the present invention can be suitably used as various packaging materials because it has suitable sealing strength and impact resistance while using plant-derived resin. In particular, since it has excellent impact resistance even in a configuration in which a laminate base material is not laminated, it can be suitably used as a packaging bag for pillow packaging or gusset packaging. In particular, since the laminated film of the present invention has a suitable matte property and excellent fusing strength, it is suitable for use as a gusset packaging bag used for packaging foods 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 being a surface layer (A) and the other surface layer being a seal layer (C). It is a laminated film. The laminated film contains a propylene-based resin in the surface layer (A) and the seal layer (C), and the intermediate layer (B) is a plant-derived biomass polyethylene (b1) fossil fuel-derived polyethylene (b2) and propylene. Contains a block copolymer resin.

[Surface layer (A)]
Examples of the propylene resin used as the resin for the surface layer (A) include propylene homopolymers; random copolymers composed of propylene and ethylene, block copolymers composed of propylene and ethylene, and other than propylene and ethylene. And a propylene resin such as a copolymer with an α-olefin. These propylene resins may be used alone or in combination of two or more. Matte laminate having suitable impact resistance and friction resistance as well as high rigidity and excellent design by including a propylene resin, preferably a propylene block copolymer resin, in the surface layer (A) It can be a film.

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 fusing strength and bag-making suitability. More preferably, it is more preferably 90% by mass or more. In addition, the resin component contained in the surface layer (A) may be a surface layer substantially composed of only a propylene-based resin.

As a propylene-based block copolymer resin that can be preferably used as a propylene-based resin, a copolymer of propylene and another α-olefin can be used. Examples of α-olefins include ethylene, 1-butene, 1-hexene, 4-methyl / 1-pentene, 1-octene, and the like because ethylene has an excellent matte feeling, cold resistance and rigidity balance. preferable. The α-olefin content in the propylene-based block copolymer is preferably 2 to 10% by mass, more preferably 4 to 8% by mass because it is easy to obtain impact resistance and rigidity.

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

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

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

BC8, BC7 (manufactured by Nippon Polypro Co., Ltd.), E150GK, F704V (Prime) are used in the surface layer (A) and have a good balance with mat feeling, fusing strength and bag making suitability. Polymer)), PC480A, PC684S, PC380A, VB370A (manufactured by Sun Allomer), and the like.

When a propylene-based block copolymer resin is used as the propylene-based resin, the content of the propylene-based block copolymer in the resin component contained in the surface layer (A) depends on mat feeling, fusing strength, and bag-making suitability. However, the content of the resin component used in the surface layer (A) is preferably 50% by mass or more, more preferably 70% by mass or more. By setting it as the said range, it becomes easy to obtain the uniform mat feeling excellent in the designability. In particular, when the impact resistance is increased, the content is preferably 80 to 100% by mass, and when the mat feeling is improved, the content is preferably 70 to 90% by mass.

In addition, when a resin other than the propylene block copolymer resin is used in the surface layer (A), various olefin resins used for the packaging film can be used in addition to the propylene resin described above. Examples of such resins include propylene homopolymer, propylene-α-olefin random copolymer (propylene-ethylene copolymer, propylene-butene-1 copolymer, propylene-ethylene-butene-1 copolymer). Polypropylene resins such as metallocene catalyst polypropylene), polyethylene resins such as very low density polyethylene (VLDPE), linear low density polyethylene (LLDPE), and low density polyethylene (LDPE), and ethylene-vinyl acetate copolymers (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 Ethylene copolymers such as crylic acid copolymer (EAA) and ethylene-methacrylic acid copolymer (EMAA); further, ionomers of ethylene-acrylic acid copolymers, ionomers of ethylene-methacrylic acid copolymers, etc. Resin can be used.

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

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 making the surface roughness within this range, the amount of other components (additives such as slip agents and antiblocking agents) can be reduced, or even if not used in combination, a film with excellent surface slipperiness can be obtained. As a result, the speed of bag making is improved, the associating after bag making and the improvement and efficiency of packing work are improved, and the workability at the time of packing by the automatic packing machine after filling the contents is improved.

The friction coefficient (ASTM D-1894) of the surface layer (A) is preferably 0.05 to 0.7, more preferably 0.07 to 0.6, and more preferably 0.1 to 0.5. By setting it as the said range, it becomes easy to improve the film feeding property at the time of packaging, the alignment property after bag making, packing workability | operativity, etc., and it becomes easy to suppress suitably the film tear at the time of binding by a closure. The friction coefficient can be adjusted by appropriately adding additives such as a lubricant and an anti-blocking agent according to the resin component used for the surface layer.

[Intermediate layer (B)]
The intermediate layer of the laminated film of the present invention is a layer containing plant-derived biomass polyethylene (b1), fossil fuel-derived polyethylene (b2), and propylene-based block copolymer resin (b3). By using the intermediate layer, the laminated film has excellent matting properties, excellent bag breaking resistance, particularly excellent bag breaking resistance and friction resistance at low temperatures, while having excellent environmental compatibility. Can be obtained.

The plant-derived biomass polyethylene (b1) used for the intermediate layer (B) is a polyethylene-based resin produced from plant-derived ethylene starting from sugarcane, corn, beet or the like. 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), and medium density polyethylene (MDPE). ), High density polyethylene (HDPE), and the like. 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 within the above range, it is easy to combine suitable fusing strength, high impact resistance, and bag breaking resistance.

The MFR of the biomass polyethylene (b1) used for the intermediate layer (B) is preferably from 0.1 to 30 g / 10 minutes, particularly preferably from 0.5 to 20 g / 10 minutes. By setting it as 1 g / 10min or more, it becomes easy to obtain suitable film forming property, and it becomes easy to obtain suitable moldability by setting it as 20 g / 10 minutes or less.

Biomass polyethylene (b1) used for the intermediate layer (B) is a plant such as sugar cane, and the production method is the same except for the production of monomers, although the raw material is a plant such as sugar cane. There is no restriction | limiting in particular as a manufacturing method, It can manufacture by the well-known method. For example, a production method using a Ziegler-Natta catalyst or a metallocene catalyst can be raised.

Specifically, a catalyst system in which a titanium-containing compound itself or a titanium-containing compound supported on a carrier such as a magnesium compound is used as a main catalyst and an organoaluminum compound is used as a co-catalyst, propylene alone or a desired α such as ethylene -A method of carrying out polymerization by adding an olefin can be mentioned. This polymerization may be any process 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 conventionally used catalyst composed of a vanadium compound and an organoaluminum compound, or a cyclopentadienyl group, a substituted cyclopentadienyl group, an indenyl group, a substituted indenyl group, etc. A metallocene system comprising a transition metal compound such as zirconium, titanium or hafnium having one or two ligands, a transition metal compound in which the ligand is geometrically controlled, and a promoter such as an aluminoxane or an ionic compound. 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 and a gas phase polymerization method in addition to homogeneous polymerization in the presence of a solvent, if necessary, using an organoaluminum compound.

Examples of such commercially available products of biomass polyethylene (b1) include SLL118, SLL118 / 21, SLL218, SLL318, SLH118, SLH218, SLH0820 / 30AF, SBC818, SPB208, STN7006, SEB853, etc. manufactured by Braschem.

The fossil fuel-derived polyethylene (b2) used for the intermediate layer (B) is a polyethylene-based resin made from fossil fuels such as petroleum. Examples of the polyethylene (b2) include linear low density polyethylene (LLDPE), linear medium density polyethylene (LMDPE), linear high density polyethylene (LHDPE), low density polyethylene (LDPE), and medium density polyethylene (MDPE). ), Polyethylene resin such as 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 (EAA), Ethylene copolymers such as lene-methacrylic acid copolymer (EMAA); and ethylene-acrylic acid copolymer ionomers, ethylene-methacrylic acid copolymer ionomers, and the like. A mixture of the above may be used. Among these, linear low density polyethylene is 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 within the above range, it is easy to combine suitable fusing strength, high impact resistance, and bag breaking resistance. One kind of linear low density polyethylene may be used, or a plurality of kinds may be used in combination.

The MFR (190 ° C., 21.18N) of the linear low density polyethylene is preferably 10 g / 10 minutes or less, more preferably 1 to 5 g / 10 minutes. By making MFR into the said range, it becomes easy to improve the film-forming property of a film, dispersibility is good, and it becomes easy to obtain a uniform film.

As the propylene-based block copolymer resin (b3) used for the intermediate layer (B), the same propylene-based block copolymer resin used for the surface layer can be preferably used. The propylene-based block copolymer may be a single copolymer or a plurality of copolymers.

Since the content of the plant-derived biomass polyethylene (b1) in the resin component contained in the intermediate layer (B) is easy to obtain suitable rigidity and impact resistance, suitability for bag making as a packaging bag, etc., 1 The mass is preferably from 35% by mass to 35% by mass, and more preferably from 2% by mass to 25% by mass. In view of reducing the environmental impact and maintaining optimum physical properties and processability, the content is more preferably 5% by mass or more, and particularly preferably 10% by mass or more. Moreover, 20 mass% or less is further more preferable, and it is especially preferable that it is 15 mass% or less.

The content of polyethylene (b2) derived from fossil fuel in the resin component contained in the intermediate layer (B) is 3% by mass or more because it is easy to obtain suitable bag making suitability, fusing seal strength, and bag breaking resistance. Preferably, it is 5 mass% or more, more preferably 7 mass% or more. Moreover, it is preferable that it is 30 mass% or less, It is more preferable that it is 20 mass% or less, It is further more preferable that it is 15 mass% or less.

The content of the propylene-based block copolymer (b3) in the resin component contained in the intermediate layer (B) is preferably 95% by mass or less because it is easy to obtain suitable impact resistance and mat feeling, 85 It is more preferably no greater than mass%, more preferably no greater than 80 mass%, and particularly preferably no greater than 75 mass%. Moreover, since it is easy to obtain the stability at the time of a bag making, it is preferable that it is 15 mass% or more, It is more preferable that it is 20 mass% or more, It is more preferable that it is 25 mass% or more, 30 mass % Or more is particularly preferable.

In addition, when only three components of biomass polyethylene (b1), fossil fuel-derived polyethylene (b2) and propylene-based block copolymer (b3) are used as the resin component contained in the intermediate layer (B), Content ratio (biomass polyethylene (b1) / fossil fuel-derived polyethylene (b2) / propylene block copolymer (b3)) is 2/3/95 to 30/25/45 by mass ratio Is preferably 10/5/85 to 25/20/55. By setting the ratio, it is possible to obtain a laminated film having an excellent rupture resistance while having a suitable matte tone, in particular, an excellent rupture resistance and friction resistance at low temperatures.

In the intermediate layer (B), resins other than those described above, for example, olefinic resins as described above may be used in combination, and among them, propylene-α-olefin random copolymers can be preferably used, particularly propylene-ethylene. A random copolymer can be preferably used. The content of α-olefin such as ethylene, butene-1,4-methylpentene-1, and octene-1 in the propylene-α-olefin random copolymer is preferably 0.3 to 10% by mass. More preferably, the content is 5 to 6% by mass. By setting the α-olefin content in the above range, it is easy to obtain suitable rigidity and blocking resistance, and it becomes easy to realize suitable bag making aptitude and packaging aptitude. The content of α-olefin such as ethylene is measured by an infrared absorption spectrum method.

The melt flow rate (MFR) of the propylene-ethylene random copolymer in the intermediate layer (B) is not particularly limited as long as it can form a laminated film, but is preferably 0.5 g / 10 min or more, It is more preferably 3 g / 10 minutes or more, and more preferably 5 g / 10 minutes or more. 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 higher, and more preferably 115 ° C. or higher, from the viewpoint of preventing adhesion to the fusing seal blade during bag making. Moreover, in order to express the fusing seal strength at the time of fusing sealing at the time of bag making, since it is necessary to form sufficient fusing balls, it is preferably 150 ° C. or less, more preferably 145 ° C. or less.

When a propylene-α-olefin random copolymer is used in the intermediate layer (B), the content of the propylene-α-olefin random copolymer in the resin component contained in the intermediate layer (B) is 5 It is preferably at least mass%, more preferably at least 15 mass%, and even more preferably at least 25 mass%. Moreover, it is preferable to set it as 50 mass% or less, It is more preferable to set it as 45 mass% or less, It is further more preferable to set it as 40 mass% or less. By using a propylene-α-olefin random copolymer for the intermediate layer, it is possible to obtain better fusing seal strength at the time of bag-making while maintaining the bag resistance.

The resin component contained in the intermediate layer (B) may be any of the above-mentioned various resins, but it is easy to suppress deterioration of rigidity and impact strength when the total thickness of the laminated film is designed to be thin. Therefore, it is preferable that the content of the propylene resin in the resin component contained in the intermediate layer (B) is 55% by mass or more and the content of the ethylene resin is 7 to 45% by mass. In particular, propylene block copolymer (b3) and propylene-ethylene random copolymer are used as the propylene resin, and the total amount of these is 55% by mass or more. As the ethylene resin, plant-derived biomass is used. It is particularly preferable that polyethylene (b1) and fossil fuel-derived polyethylene (b2) are used and the total amount thereof is 7 to 45% by mass.

Further, only the biomass polyethylene (b1), the fossil fuel-derived polyethylene (b2), the propylene-based block copolymer (b3) and the propylene-ethylene random copolymer are used as the resin component contained in the intermediate layer (B). The ratio of these contents (biomass polyethylene (b1) / polyethylene derived from fossil fuel (b2) / propylene-based block copolymer (b3) / propylene-ethylene random copolymer) is 2/3 / by mass. 65/30 to 25/20/15/40 is preferable, and 10/5/50/35 to 15/15/30/40 is more preferable. By setting the ratio, it is possible to obtain a laminated film having excellent tear resistance while having a suitable matte tone, particularly excellent tear resistance and friction resistance at low temperatures.

In addition, you may use suitably the additive which was illustrated in the said surface layer also in the said intermediate | middle layer.

[Sealing layer (C)]
The sealing layer (C) used for this invention is a layer used for adhesion | attachment of the sealing layers of laminated | multilayer film, and adhesion | attachment with a laminated | multilayer film, another container, a film, etc. What is necessary is just to select suitably the resin seed | species from which the suitable sealing strength is obtained for the said sealing layer according to a use aspect or to-be-sealed object. For example, when used as a packaging bag by sealing the seal layers, propylene-α- such as propylene-ethylene random copolymer, propylene-1-butene copolymer, etc. is obtained from the point that an appropriate seal strength can be obtained. A seal layer containing an α-olefin-propylene copolymer such as an olefin copolymer or 1-butene-propylene copolymer can be suitably used. Among them, propylene-1-butene is easy to adjust heat seal temperature and strength at easy opening seal at low temperature, wide heat seal temperature range, and easy to obtain appropriate heat seal strength as easy open seal. A butene-based resin such as a polymer or a 1-butene-propylene copolymer is preferred.

When a propylene-1-butene copolymer or a 1-butene-propylene copolymer is used, it is easy to obtain suitable sealing properties and blocking resistance, so that the 1-butene content in the copolymer is 60%. It is preferably ˜95 mol%, more preferably 65 to 95%, and even more preferably 70 to 90 mol%. In addition, the propylene content is preferably 2 to 10% by mole, more preferably 3 to 9% by mole, and further preferably 4 to 8% by mole because a suitable low-temperature sealability is easily obtained. preferable.

When a butene resin such as propylene-1-butene copolymer or 1-butene-propylene copolymer is used, the content of butene resin is 50% by mass or less in the resin component contained in the seal layer. Preferably, it is 40 mass% or less, more preferably 30 mass% or less. Moreover, it is preferable to set it as 10 mass% or more, and it is more preferable to set it as 15 mass% or more. When the content of the butene-based resin is within this range, it is easy to obtain suitable low-temperature sealing properties, fusing strength and tear resistance of bag-made products, and it is advantageous for cost reduction.

As the resin used in combination with the butene-based resin, other polyolefin-based resins can be used as appropriate. However, since the seal strength is easily adjusted, a propylene-α-olefin copolymer or an ethylene-α-olefin copolymer can be used. Polymers can be preferably used, and propylene-α-olefin copolymers can be particularly preferably used.

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

The content of the other olefinic resin is preferably 90% by mass or less, 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 sealing properties. . 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, when providing an easy-opening part in which the sealing layers are heat-sealed, a butene-based resin and a propylene-α-olefin copolymer, It is preferable to use in combination at a ratio such that the mass ratio represented by the butene resin / propylene-α-olefin copolymer is 20/80 to 50/50.

In the seal layer (C), various additives may be blended within a range not impairing the effects of the present invention. Examples of the additive include an antioxidant, a weather resistance stabilizer, an antistatic agent, an antifogging agent, an antiblocking agent, a lubricant, a nucleating agent, and a pigment.

The friction coefficient (ASTM D1894) of the seal layer (C) surface is preferably 0.01 to 0.4, more preferably 0.02 to 0.35, and more preferably 0.05 to 0.30. By setting it as the said range, it becomes easy to improve the packaging work by the film feedability at the time of packaging, the wrinkle after bag making, and suppression of swell. In addition, it is easy to suppress scratches caused by rubbing between the contents when filling the contents such as bread and the film inner surface, and to improve wear resistance and tear resistance, and to easily suppress film tearing. The friction coefficient can be adjusted by appropriately adding additives such as a lubricant and an anti-blocking agent according to the resin component used for the seal layer.

[Laminated film]
The laminated film of the present invention is a laminated film having at least the above-mentioned surface layer, intermediate layer and seal layer, and is a laminated film in which one surface layer of the laminated film is a surface layer and the other surface layer is a seal layer. The laminated film having such a configuration can be suitably used as a film for various packaging because it has a suitable fusing seal strength and is excellent in impact resistance and bag breaking resistance.

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

The thickness 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, more preferably 5 to 20 μm. The thickness of the seal layer is preferably 1 to 10 μm, and more preferably 2 to 8 μm.

Further, the thickness ratio of the surface layer is preferably 15% or more, more preferably 20% or more of the total thickness of the laminated film, because it is easy to obtain a suitable matte feeling, fusing strength and bag-making suitability. . Moreover, it is preferable to set it as 40% or less, and it is more preferable to set it as 35% or less. The thickness ratio of the intermediate layer is preferably 30% or more, more preferably 40% or more of the total thickness of the laminated film because it is easy to obtain suitable matte feeling, fusing strength, and bag-making suitability. Moreover, it is preferable to set it as 70% or less, and it is more preferable to set it as 65% or less. The thickness ratio of the seal layer is preferably 5% to 30%, more preferably 10 to 25% of the total thickness of the laminated film, since it is easy to obtain suitable easy-openability, fusing 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 from the viewpoint of reducing environmental burden, and is 3% by mass or more. Is more preferable, and it is more preferable that it is 5 mass% or more.

The haze of the laminated film of the present invention is preferably 35% or more, and more preferably 55% or more because it is easy to obtain a suitable matte design. Moreover, when ensuring the visibility of the contents, the haze is preferably 80% or less, and more preferably 70% or less.

The laminated film of the present invention may be laminated with any other resin layer other than the surface layer, intermediate layer and seal layer, but the thickness of the other resin layer is 20% or less of the total thickness. The structure composed of the surface layer, the intermediate layer, and the seal layer is particularly preferable. In this configuration, an intermediate layer in which a plurality of intermediate layers are stacked may be used.

Specific examples of the layer structure include a three-layer structure of surface layer / intermediate layer / sealing 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. Preferred examples include: / intermediate layer 1 / intermediate layer 2 / four-layer structure of seal layer. Especially, since adjustment of the characteristic of a film and manufacture of a film are easy, the 3 layer structure which consists of a surface layer / intermediate layer / sealing layer can be used preferably.

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

The surface layer is preferably subjected to a surface treatment in order to improve adhesion with printing ink. Examples of such surface treatment include corona treatment, plasma treatment, chromic acid treatment, flame treatment, hot air treatment, surface oxidation treatment such as ozone / ultraviolet treatment, and surface unevenness treatment such as sandblasting. Corona treatment is preferable.

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

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

Moreover, when it is set as the packaging bag for bread, it can be set as the packaging bag which has a gusset part by folding and sealing a printing surface. 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 sealing layer of the laminated film of the present invention is inside the bag. Since the laminated film of the present invention can realize suitable fusing strength and bag making suitability, it can be particularly suitably used as a bottom gusset bag. The fusing seal temperature and the bag making speed are adjusted so that the fusing seal strength of the side part of the bottom gusset bag and the bottom gusset part (folded part of the bottom part) is 7.5 N to 30 N / 15 mm, preferably 10 to 30 N / 15 mm. It is preferable.

The obtained bottom gusset bag is supplied to a bread bread automatic filling machine, and after filling bread, 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 to make an easily openable bread wrapping bag, and if necessary, form an easily openable seal part at the top of the bag, preferably the top of the bread, and the top of the bag with a plastic plate, tape, string, etc. You may seal by bundling using this binding tool.

Also, when collecting various types of bread such as butter rolls, use a horizontal pillow type automatic packaging machine such as FW-3400αV type manufactured by Fujikikai Co., Ltd. so that the seal layer is inside the bag. Supplied in roll form. In the horizontal pillow type automatic packaging machine, the heat seal surfaces of the film are overlapped and heat sealed to form a bag and to enclose the bread. At this time, it is preferable to adjust the heat sealing temperature and the packaging speed so that the sealing strength of the bottom portion and the back pasting portion of the pillow packaging bag by the packaging machine is 7.5 N to 30 N / 15 mm, preferably 8 to 20 N / 15 mm. . Next, an easily openable seal portion may be formed by heat sealing under conditions that allow easy opening and a heat seal strength of 0.1 to 5 N / 15 mm, preferably 0.2 to 4 N / 15 mm. May be bound using a binding tool such as a plastic plate, tape, or string.

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

As described above, since the laminated film of the present invention can realize suitable impact resistance and bag breaking 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 that are often packaged and distributed 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 and a heel portion is used, it is difficult for bag breakage at the time of binding to occur, In addition, even when contact with the binding tool or the transport container occurs during transfer, pinholes and tears are unlikely to occur. In addition, it is difficult to cause pinholes and tears due to rubbing between the food as the contents and the inner surface of the film (seal surface), friction between the mixed plastic tray and piercing. Furthermore, since the laminated film of the present invention can ensure a suitable fusing seal strength even when a gusset portion is formed, it can be particularly suitably applied to bread packaging applications.

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

Example 1
A resin mixture for forming each layer was prepared by using the following resins as resin components for forming each layer of the surface layer, the intermediate layer, and the seal layer. Each of these mixtures was supplied to three extruders and coextruded so that the average thickness of each layer of the laminated film formed by the surface layer / intermediate layer / sealing layer was 7/18/5 μm. A 30 μm laminated film was formed. Subsequently, the surface layer of the obtained laminated film was subjected to a corona discharge treatment so that the surface energy was 35 mN / m to obtain a laminated film.
Surface layer: propylene-ethylene block copolymer resin (propylene-derived component content: 90% by mass, density: 0.90 g / cm ³ , MFR (measuring temperature 230 ° C.): 5 g / 10 min) (hereinafter referred to as propylene block copolymer) 100 parts by mass of polymer (referred to as polymer (1)) Intermediate layer: propylene-ethylene block copolymer (density: 0.90 g / cm ³ , MI: 8 g / 10 minutes, melting point 160 ° C.) (hereinafter referred to as propylene block copolymer) 40 parts by mass of a copolymer (referred to as (2)), a propylene-ethylene random copolymer (ethylene content: 5.2%, density: 0.90 g / cm ³ , MFR: 5.4 g / 10 minutes) (hereinafter referred to as COPP ( 1) and referred to) 35 parts by weight, linear low density polyethylene ^{(density: 0.905g / cm 3, MFRI:} 4.0g / 10 minutes) (hereinafter, the LLDPE (1) To) 10 parts by weight, and bio-polyethylene (Braskem Co. linear low density polyethylene SLH218 ^{(density: 0.916g / cm 3, MFR =} 2.3g / 10 min) (hereinafter, referred to as bio-PE (1)) 15 parts by mass of resin mixture Seal layer: propylene-ethylene random copolymer (ethylene-derived component content: 5.0% by mass, density: 0.90 g / cm ³ , MFR (measuring temperature 230 ° C.): 7 g / 10 minutes) 70 parts by mass (hereinafter referred to as COPP (2)), 1-butene-propylene copolymer (density: 0.90 g / cm ³ , MFR (measuring temperature 230 ° C.): 4 g / 10 minutes) 30 parts by weight of butene copolymer (referred to as (1))

(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 as follows.
Intermediate layer: propylene block copolymer (2) 42 parts by mass, COPP (1) 35 parts by mass, LLDPE (1) 3 parts by mass, bio PE (1) 20 parts by mass

(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 as follows.
Intermediate layer: 45 parts by mass of propylene-based block copolymer (2), 35 parts by mass of COPP (1), 15 parts by mass of LLDPE (1), 5 parts by mass of bio PE (1)

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 as follows.
Intermediate layer: 45 parts by mass of propylene-based block copolymer (2), 40 parts by mass of COPP (1), 13 parts by mass of LLDPE (1), 2 parts by mass of bio PE (1)

(Example 5)
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 as follows.
Intermediate layer: propylene block copolymer (2) 35 parts by mass, COPP (1) 35 parts by mass, LLDPE (1) 5 parts by mass, bio PE (1) 25 parts by mass

(Example 6)
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 as follows.
Intermediate layer: 75 parts by mass of propylene-based block copolymer (2), 10 parts by mass of LLDPE (1), 15 parts by mass of bio PE (1)

(Example 7)
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 as follows.
Intermediate layer: 72 parts by mass of propylene-based block copolymer (2), 3 parts by mass of LLDPE (1), 25 parts by mass of bio PE (1)

(Example 8)
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 as follows.
Intermediate layer: 75 parts by mass of propylene-based block copolymer (2), 15 parts by mass of LLDPE (1), 10 parts by mass of bio PE (1)

Example 9
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 as follows.
Intermediate layer: 65 parts by mass of propylene-based block copolymer (2), 10 parts by mass of LLDPE (1), 25 parts by mass of bio PE (1)

(Example 10)
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 as follows.
Intermediate layer: 65 parts by mass of propylene-based block copolymer (2), 20 parts by mass of LLDPE (1), 15 parts by mass of bio PE (1)

(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 as follows.
Intermediate layer: 55 parts by mass of propylene-based block copolymer (2), 5 parts by mass of LLDPE (1), 40 parts by mass of bio PE (1)

(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 as follows.
Intermediate layer: propylene homopolymer (density: 0.90 g / cm 3, MFR: 8 g / 10 min) (hereinafter referred to as HOPP (1)) 85 parts by mass, bio PE (1) 15 parts by mass

(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 as follows.
Intermediate layer: 45 parts by mass of propylene-based block copolymer (2), 40 parts by mass of COPP (1), 15 parts by mass of LLDPE (1)

The following tests and evaluations were performed using the laminated films obtained in the above examples and comparative examples. The results obtained are as shown in the table below.

[Measurement of rigidity]
Using a Tensilon tensile tester (manufactured by A & D Co., Ltd.) based on ASTM D-882, the 1% tangential modulus (unit: MPa) at 23 ° C. of the films obtained in Examples and Comparative Examples was used. 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”) during film production.
○: Rigidity is 550 MPa or more Δ: Rigidity is 450 or more and less than 550 MPa ×: Rigidity is less than 450 MPa

[Measurement of haze, matte evaluation]
The haze of the films obtained in Examples and Comparative Examples was measured (unit:%) using a haze meter (manufactured by Nippon Denshoku Kogyo Co., Ltd.) based on JIS K7105. The mat property was evaluated according to the following criteria.
○: Haze of 55% or more Δ: Haze of 35% or more and less than 55% ×: Haze of less than 35%

[Evaluation of bag aptitude]
The film obtained in the Examples and Comparative Examples was folded in half with the sealing layer inside, and then gusseted in the bottom, and fused and sealed at a sealing temperature (bag-making temperature) of 300 ° C. Machine: Tokani Giken Factory Co., Ltd. HK-40, bag making speed: 120 sheets / min) to produce a bottom gusset bag (length: 345 mm (side portion: 245 mm, gusset portion: 60 mm), width 235 mm), The suitability for bag making was evaluated. In addition, 300 sheets were grouped together as a set and bundled into a bundle to evaluate the alignment characteristics.
○: The film follows the bag even at a bag-making speed of 120 shots, and there is no problem with the alignment. Δ: The film follows the bag-making speed at 120 shots, but the alignment property becomes a problem. There are things that can not follow the bag speed, poor alignment

[Fusing strength]
Using the films obtained in Examples and Comparative Examples, bottom gusset bags were produced in the same manner as in the bag-making suitability evaluation. From the center of the gusset portion on both sides of the obtained five bottom gusset bags and the center of the side portion other than the gusset, respectively, a test piece having a length of 70 mm and a width of 15 mm is set so that the fusing seal portion is the center portion in the length direction. 10 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 fusing strength.
○: The fusing strength of the gusset part and the side part is 15 N / 15 mm or more. Δ: The fusing strength of the gusset part and the side part is both 12 N / 15 mm and less than 15 N / 15 mm. X: At least one fusing of the gusset part and the side part. Strength is less than 12N / 15mm

[Heat seal strength]
Using the films obtained in Examples and Comparative Examples, bottom gusset bags were produced in the same manner as in the bag-making suitability evaluation. A heat sealer (Tester Sangyo Co., Ltd .: pressure 0.2 MPa, time 1 second, seal temperature: upper seal bar 95 ° C., parallel to the 50 mm portion and the opening downward from the upper end of the opening of the obtained bottom gusset bag. Heat sealing was performed at a lower seal bar of 50 ° C. and a seal bar shape: a plane of 300 m × 10 mm. From the obtained heat-seal part of the five bottom gusset bags, 10 pieces of test pieces each having a length of 70 mm and a width of 15 mm were cut out by two pieces each so that the heat-seal part was the central part in the width direction, and 23 ° C. The maximum load when peeling 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 5N / 15mm, no film tear when peeled off ×: Heat seal strength is 5N / 15mm or more, or film tear when peeled off

[Measurement of impact strength]
The films obtained in Examples and Comparative Examples were held in a thermostatic chamber adjusted to 0 ° C. for 6 hours, and then impact strength by a film impact method using a spherical metallic impact head having a diameter of 1.5 inches. Was measured.
◎: Impact strength is 0.3 (J) or more ○: Impact strength is 0.2 (J) or more and less than 0.3 △: Impact strength is 0.1 (J) or more and less than 0.2 ×: Impact strength is 0 Less than 1 (J)

As is clear from the above table, the laminated films of the present invention of Examples 1 to 10 have favorable matte appearance, suitable seal strength, impact resistance, and friction resistance, and excellent bag breaking resistance. It was a thing. On the other hand, the laminated films of Comparative Examples 1 and 2 were unable to combine suitable impact resistance and fusing seal strength.

Claims

A laminated film in which a surface layer (A), an intermediate layer (B), and a seal layer (C) are laminated,
The surface layer (A) and the seal layer (C) contain a propylene resin,
The said intermediate | middle layer (B) contains the biomass polyethylene (b1) derived from a plant, the polyethylene (b2) derived from a fossil fuel, and the propylene-type block copolymer resin (b3), The laminated film characterized by the above-mentioned.
The laminated film according to claim 1, wherein the fossil fuel-derived polyethylene (b2) in the intermediate layer (B) is a linear low density polyethylene.
The content of plant-derived biomass polyethylene (b1) in the resin component contained in the intermediate layer (B) is 1 to 35% by mass, and the content of polyethylene (b2) derived from fossil fuel is 3 to 30% by mass. The laminated film according to claim 1 or 2.
The resin component contained in the intermediate layer (B) is composed of biomass polyethylene (b1), polyethylene (b2) derived from fossil fuel, and propylene-based block copolymer (b3), and the biomass polyethylene in the intermediate layer (B) ( 2. The content ratio represented by (b1) / polyethylene derived from fossil fuel (b2) / propylene block copolymer (b3) is 2/3/95 to 30/25/45 in mass ratio. 4. The laminated film according to any one of items 1 to 3.
The laminated film according to any one of claims 1 to 3, wherein the intermediate layer (B) contains a propylene-ethylene random copolymer resin.
The resin component contained in the intermediate layer (B) is composed of biomass polyethylene (b1), fossil fuel-derived polyethylene (b2), propylene-based block copolymer (b3), and propylene-ethylene random copolymer. The ratio of the content expressed by biomass polyethylene (b1) / polyethylene derived from fossil fuel (b2) / propylene block copolymer (b3) / propylene-ethylene random copolymer in (B) is in mass ratio. The laminated film according to claim 5, which is 2/3/65/30 to 25/20/15/40.
The laminated film according to any one of claims 1 to 6, wherein the surface layer (A) contains 50% by mass or more of a propylene-based block copolymer resin in the resin component contained in the surface layer (A).
The laminated film according to any one of claims 1 to 7, wherein the seal layer (C) contains a propylene-ethylene copolymer resin and a butene resin.
The laminated film according to any one of claims 1 to 8, which has a haze value of 30% or more.
The melt flow rate of the plant-derived biomass polyethylene (b1) in the intermediate layer (B) is 0.50 to 5 [g / 10 min], and the melt flow rate of the fossil fuel-derived polyethylene (b2) is 3 to 10 The laminated film according to any one of claims 1 to 9, which is [g / 10 min].
A food packaging bag using the laminated film according to any one of claims 1 to 10.
The food packaging bag according to claim 11, further comprising a gusset portion.
The food packaging bag according to claim 11 or 12, which is used for bread packaging.