Heat-sealable laminated film

Abstract

To provide a polyethylene-based laminated film suitably used for a packaging bag or the like, which has an excellent laminate strength with a film on an outer layer side and has excellent blocking resistance while maintaining excellent properties such as seal strength and impact resistance.SOLUTION: There is provided a laminated film having (A) a heat fusion layer, (B) an intermediate layer and (C) a laminate layer, each of which contains a linear low density polyethylene derived from petroleum, wherein at least one layer of the heat fusion layer (A), the intermediate layer (B) and the laminate layer (C) contains at least 3% or more of a plant-derived biomass linear low density polyethylene.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a polyethylene-based laminated film, and more specifically, to a laminated film that is suitably used as a packaging film, has excellent lamination strength with an outer-layer film and excellent antiblocking properties, and reduces the environmental load by using a plant-derived resin.

Background Art

[0002] A packaging bag formed by heat-sealing a plastic multilayer film is widely used for storing various contents such as foods, beverages, detergents, shampoos, and cosmetics. As a film constituting the inner layer that becomes the heat-sealing part of such a plastic multilayer film, a three-layer polyethylene-based laminated film composed of a heat-sealing layer, an intermediate layer, and a laminate layer in which a base film (base material layer) is laminated on the outer side thereof from the innermost layer side has been variously proposed (see, for example, Patent Document 1). These laminated films were designed to have suitable properties from the viewpoints of seal strength, impact resistance, antiblocking properties, etc., but in recent years, an improvement in the lamination strength with the outer-layer film and a further improvement in the antiblocking properties have been demanded.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In view of the above technical background, an object of the present invention is to provide a polyethylene-based laminated film suitably used for a packaging bag or the like, which has excellent lamination strength with an outer-layer film and excellent antiblocking properties while maintaining excellent properties such as seal strength and impact resistance. [Means for Solving the Problems]

[0005] As a result of intensive studies, the present inventors have found that in a laminated film having a heat-sealing layer, an intermediate layer, and a laminate layer each containing petroleum-derived linear low-density polyethylene, by adding biomass-derived linear low-density polyethylene to at least one of these layers, the lamination strength is significantly improved and the blocking resistance can also be improved, and thus the present invention has been completed. That is, the present invention relates to [1] A laminated film having (A) a heat-sealing layer, (B) an intermediate layer, and (C) a laminate layer each containing petroleum-derived linear low-density polyethylene, wherein at least one of the (A) heat-sealing layer, (B) intermediate layer, and (C) laminate layer contains at least 3% or more of plant-derived biomass linear low-density polyethylene. relates to the above laminated film.

[0006] Hereinafter, [2] to [6] are all preferred embodiments or one embodiment of the present invention. [2] The laminated film according to [1], wherein the (C) laminate layer contains at least 3% or more of plant-derived biomass linear low-density polyethylene. [3] The laminated film according to [1] or [2], wherein the heat of fusion ΔH at 0°C to 130°C calculated from the melting curve obtained by DSC measurement is 135 to 164 J / g. [4] The laminated film according to any one of [1] to [3], wherein the molecular weight distribution Mw / Mn of the plant-derived biomass linear low-density polyethylene is 3.5 or more. [5] The laminated film according to any one of [1] to [4], having a (D) base material layer on the side of the (C) laminate layer, either directly or via an adhesive layer. [6] A packaging bag comprising the laminated film according to any one of [1] to [5]. [Advantages of the Invention]

[0007] While maintaining the excellent properties of conventional polyethylene-based laminated films such as seal strength and impact resistance, the laminated film of the present invention significantly improves the laminate strength and the like, and also reduces the environmental load in its production and the like. It has high practical value at a high level beyond the limits of the prior art and can be suitably used in various applications including packaging bags.

Embodiments for Carrying Out the Invention

[0008] The present invention is a laminated film having (A) a heat-sealing layer, (B) an intermediate layer, and (C) a laminate layer each containing a linear low-density polyethylene derived from petroleum, wherein at least one of the (A) heat-sealing layer, (B) intermediate layer, and (C) laminate layer contains at least 3% or more of a biomass linear low-density polyethylene derived from plants. That is, the laminated film of the present invention contains a linear low-density polyethylene derived from petroleum in each of the (A) heat-sealing layer, (B) intermediate layer, and (C) laminate layer. In addition, the laminated film of the present invention contains a predetermined amount of a biomass linear low-density polyethylene derived from plants in at least one of the (A) heat-sealing layer, (B) intermediate layer, and (C) laminate layer.

[0009] Petroleum-derived linear low-density polyethylene The linear low-density polyethylene derived from petroleum used in the present invention is a homopolymer of ethylene produced using petroleum as a raw material, or a copolymer of ethylene produced using petroleum as a raw material and an α-olefin, and may be synthesized by a known production method.

[0010] As the α-olefin, compounds having 3 to 20 carbon atoms can be used. For example, propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-dodecene, 4-methyl-1-pentene, 4-methyl-1-hexene, etc. can be mentioned, and mixtures thereof may also be used. The α-olefin is preferably a compound having 4, 6 or 8 carbon atoms or a mixture thereof, and is 1-butene, 1-hexene, 1-octene or a mixture thereof.

[0011] The petroleum-derived linear low-density polyethylene may be a commercially available product. For example, 2040F (C6-LLDPE, MFR; 4.0, density; 0.918 g / cm 3 ) manufactured by Ube Maruzen Polyethylene Co., Ltd. can be used.

[0012] The petroleum-derived linear low-density polyethylene preferably has a density of 0.905 to 0.935 g / cm 3 , more preferably 0.915 to 0.930 g / cm 3 , and the MFR is preferably 0.5 to 6.0 g / 10 min, more preferably 2.0 to 4.0 g / 10 min.

[0013] The petroleum-derived linear low-density polyethylene preferably has a molecular weight distribution (expressed as the ratio of weight average molecular weight: Mw, to number average molecular weight: Mn, Mw / Mn) of 1.5 to 4.0, more preferably in the range of 1.8 to 3.5. This Mw / Mn can be measured by gel permeation chromatography (GPC).

[0014] The petroleum-derived linear low-density polyethylene has one or more sharp peaks determined from the endothermic curve measured at a heating rate of 10 °C / min with a differential scanning calorimeter (DSC), and the highest temperature of the peak, that is, the melting point is preferably 95 to 140 °C, more preferably in the range of 105 to 130 °C.

[0015] Petroleum-derived linear low-density polyethylene can be produced by a conventionally known production method using a conventionally known catalyst such as a multi-site catalyst like a Ziegler catalyst or a single-site catalyst like a metallocene catalyst. From the viewpoint of obtaining linear low-density polyethylene with a narrow molecular weight distribution and capable of forming a high-strength film, it is preferable to use a single-site catalyst.

[0016] The above single-site catalyst is a catalyst capable of forming a uniform active species, and is usually adjusted by bringing a metallocene-based transition metal compound or a non-metallocene-based transition metal compound into contact with an activating cocatalyst. The single-site catalyst is preferable because, compared with a multi-site catalyst, the active site structure is uniform, so that a polymer with a high molecular weight and a high degree of uniformity can be polymerized. As the single-site catalyst, it is particularly preferable to use a metallocene-based catalyst. The metallocene-based catalyst is a catalyst containing a transition metal compound of Group IV of the periodic table containing a ligand having a cyclopentadienyl skeleton, a cocatalyst, an organometallic compound if necessary, and each catalyst component of a carrier.

[0017] In the transition metal compound of Group IV of the periodic table containing a ligand having the above cyclopentadienyl skeleton, the cyclopentadienyl skeleton is a cyclopentadienyl group, a substituted cyclopentadienyl group, etc. The substituted cyclopentadienyl group has at least one substituent selected from hydrocarbon groups having 1 to 30 carbon atoms, silyl groups, silyl-substituted alkyl groups, silyl-substituted aryl groups, cyano groups, cyanoalkyl groups, cyanoaryl groups, halogen groups, haloalkyl groups, halosilyl groups, etc. The substituted cyclopentadienyl group may have two or more substituents, and the substituents may be bonded to each other to form a ring, such as an indenyl ring, a fluorenyl ring, an azulene ring, or a hydrogenated product thereof. The ring formed by the substituents bonded to each other may further have substituents.

[0018] In a Group 4 transition metal compound containing a ligand having a cyclopentadienyl skeleton, examples of the transition metal include zirconium, titanium, hafnium, etc., and zirconium and hafnium are particularly preferred. The transition metal compound usually has two ligands having a cyclopentadienyl skeleton, and it is preferable that the ligands having a cyclopentadienyl skeleton are bonded to each other by a bridging group. Examples of the bridging group include an alkylene group having 1 to 4 carbon atoms, a silylene group, a dialkylsilylene group, a substituted silylene group such as a diarylsilylene group, a dialkylgermylene group, a substituted germylene group such as a diarylgermylene group, etc. Preferably, it is a substituted silylene group.

[0019] In a Group 4 transition metal compound of the periodic table, as ligands other than the ligand having a cyclopentadienyl skeleton, typical ones include hydrogen, a hydrocarbon group having 1 to 20 carbon atoms (alkyl group, alkenyl group, aryl group, alkylaryl group, aralkyl group, polyenyl group, etc.), halogen, metaalkyl group, metaaryl group, etc.

[0020] The Group 4 transition metal compound of the periodic table containing the ligand having the above cyclopentadienyl skeleton can use one kind or a mixture of two or more kinds as a catalyst component.

[0021] The cocatalyst refers to one that can effectively deactivate the above Group 4 transition metal compound of the periodic table as a polymerization catalyst or can balance the ionic charges in a catalytically activated state. Examples of the cocatalyst include a benzene-soluble aluminoxane or a benzene-insoluble organoaluminum oxy compound of an organoaluminum oxy compound, an ion-exchangeable layered silicate, a boron compound, an ionic compound composed of a cation containing or not containing an active hydrogen group and a non-coordinating anion, a lanthanoid salt such as lanthanum oxide, tin oxide, a phenoxy compound containing a fluoro group, etc.

[0022] Transition metal compounds of Group IV of the periodic table containing a ligand having a cyclopentadienyl skeleton may be used by being supported on a carrier of an inorganic or organic compound. As the carrier, a porous oxide of an inorganic or organic compound is preferable. Specifically, ion-exchangeable layered silicates such as montmorillonite, SiO2, Al2O3, MgO, ZrO2, TiO2, B2O3, CaO, ZnO, BaO, ThO2, etc. or mixtures thereof may be mentioned.

[0023] Furthermore, examples of the organometallic compounds that may be used as necessary include organoaluminum compounds, organomagnesium compounds, organozinc compounds, etc. Among these, organoaluminum is preferably used.

[0024] The linear low-density polyethylene derived from petroleum may be used alone or in combination of two or more. Also, it may be used together with other polymers including other ethylene-based polymers.

[0025] The linear low-density polyethylene derived from petroleum can be blended with various known additives usually added to olefin polymers, such as antioxidants, weather stabilizers, antistatic agents, antifogging agents, antiblocking agents, slip agents (lubricants), etc., as long as the object of the present invention is not impaired.

[0026] Plant-derived biomass linear low-density polyethylene The biomass linear low-density polyethylene derived from plants used in the present invention is a linear low-density polyethylene obtained by polymerizing ethylene produced using plants as a raw material. In the present invention, the above-mentioned biomass linear low-density polyethylene derived from plants is a linear low-density polyethylene obtained by polymerizing a monomer containing ethylene derived from biomass as described later. Therefore, except that it is obtained by polymerizing a monomer containing ethylene derived from biomass, it preferably has the same physical properties as conventional linear low-density polyethylene. For example, the "linear low density polyethylene" in the present application is preferably an ethylene-based (co)polymer having 10 to 30 SCBs (side chains having 1 to 5 carbon atoms, also referred to as "short chain branches") per 1000 carbon atoms.

[0027] The plant-derived biomass linear low density polyethylene may be a commercially available product. For example, those manufactured and sold by Braskem can be used. Specifically, the product with the brand name: SLH218 can be preferably used. The plant-derived biomass linear low density polyethylene used in the present invention is obtained by polymerizing monomers containing ethylene derived from biomass. For the ethylene derived from biomass, it is preferable to use, but not limited to, that obtained by the following production method. Since ethylene derived from biomass is used as the monomer which is the raw material, the resulting linear low density polyethylene is derived from biomass. Note that the raw material monomer of the linear low density polyethylene does not have to contain 100% by mass of ethylene derived from biomass, and may contain ethylene not derived from biomass or raw material monomers other than ethylene.

[0028] The production method of biomass ethylene which is the raw material of the plant-derived biomass linear low density polyethylene is not particularly limited, and can be obtained by a conventionally known method. Hereinafter, an example of the production method of biomass ethylene will be described.

[0029] Biomass ethylene can be produced using biomass-derived ethanol as a raw material. In particular, it is preferable to use biomass-derived fermented ethanol obtained from plant raw materials. The plant raw materials are not particularly limited, and conventionally known plants can be used. For example, corn, sugarcane, beet, and cassava can be mentioned.

[0030] In the present invention, the fermented ethanol derived from biomass refers to ethanol that has been produced by contacting a culture solution containing a carbon source obtained from plant raw materials with a microorganism that produces ethanol or a product derived from its disrupted cells, and then purified. Conventional well-known methods such as distillation, membrane separation, and extraction can be applied to purify ethanol from the culture solution. For example, methods such as adding benzene, cyclohexane, etc. and performing azeotropic distillation, or removing water by membrane separation, etc. can be mentioned. In order to obtain biomass ethylene, at this stage, further advanced purification such as reducing the total amount of impurities in ethanol to 1 ppm or less may be performed.

[0031] When obtaining ethylene by the dehydration reaction of ethanol, a catalyst is usually used. This catalyst is not particularly limited, and conventionally well-known catalysts can be used. Advantageous in the process is a fixed-bed flow reaction in which the separation of the catalyst and the product is easy. For example, γ-alumina, etc. is preferable. Since this dehydration reaction is an endothermic reaction, it is usually carried out under heating conditions. At a commercially useful reaction rate As the reaction proceeds, the heating temperature is not limited, but preferably a temperature of 100°C or higher, more preferably 250°C or higher, and even more preferably 300°C or higher is appropriate. The upper limit is also not particularly limited, but from the viewpoints of energy balance and equipment, it is preferably 500°C or lower, more preferably 400°C or lower. The reaction pressure is not particularly limited either, but a pressure of normal pressure or higher is preferable in order to facilitate subsequent gas-liquid separation. Industrially, a fixed-bed flow reaction in which the separation of the catalyst is easy is suitable, but a liquid-phase suspension bed, fluidized bed, etc. may also be used.

[0032] In the dehydration reaction of ethanol, the reaction yield is determined by the water content in the ethanol supplied as a raw material. Generally, when performing a dehydration reaction, considering the water removal efficiency, it is preferable to have no water. However, in the case of the dehydration reaction of ethanol using a solid catalyst, it has been found that the production amount of other olefins, particularly butene, tends to increase when there is no water. Presumably, it is speculated that without a small amount of water, the dimerization of ethylene after dehydration cannot be suppressed. The lower limit of the allowable water content needs to be 0.1% by mass or more, preferably 0.5% by mass or more. The upper limit is not particularly limited, but from the viewpoints of material balance and heat balance, it is preferably 50% by mass or less, more preferably 30% by mass or less, and even more preferably 20% by mass or less.

[0033] By performing the dehydration reaction of ethanol in this way, a mixture of ethylene, water, and a small amount of unreacted ethanol can be obtained. However, since ethylene is a gas at normal temperature at about 5 MPa or less, water and ethanol can be removed from these mixtures by gas-liquid separation to obtain ethylene. This method may be carried out by a known method. The ethylene obtained by gas-liquid separation is further distilled. Except that the operating pressure at this time is equal to or higher than atmospheric pressure, the distillation method, operating temperature, residence time, etc. are not particularly restricted.

[0034] When the raw material is fermented ethanol derived from biomass, the obtained ethylene contains trace amounts of carbonyl compounds such as ketones, aldehydes, and esters, which are impurities mixed in the ethanol fermentation process, as well as carbon dioxide gas, which is a decomposition product thereof, and nitrogen-containing compounds such as amines and amino acids, which are decomposition products and contaminants of enzymes, and ammonia, which is a decomposition product thereof. In the production and use of polyethylene, these trace amounts of impurities may cause problems, so they may be removed by purification. The purification method is not particularly limited and can be carried out by a conventionally known method. As a suitable purification operation, for example, an adsorption purification method can be mentioned. The adsorbent to be used is not particularly limited, and a conventionally known adsorbent can be used. For example, a material with a high surface area is preferable, and the type of adsorbent is selected according to the type and amount of impurities in the ethylene obtained by the dehydration reaction of biomass-derived fermented ethanol.

[0035] In addition, caustic water treatment may be used in combination as a method for purifying impurities in ethylene. When performing caustic water treatment, it is desirable to carry it out before adsorption purification. In that case, it is necessary to perform a moisture removal treatment after the caustic treatment and before the adsorption purification.

[0036] The monomer, which is a raw material for plant-derived biomass linear low-density polyethylene, may further contain ethylene and / or α-olefin derived from fossil fuels, or may further contain α-olefin derived from biomass.

[0037] The carbon number of the above α-olefin is not particularly limited, but usually, those having 3 to 20 carbon atoms can be used, and it is preferably butylene, hexene, or octene. This is because if it is butylene, hexene, or octene, it can be produced by the polymerization of ethylene, which is a biomass-derived raw material. In addition, by including such an α-olefin, the linear low-density polyethylene obtained by polymerization has an alkyl group as a branched structure, so it can be made more flexible than a simple linear one.

[0038] It is preferable from the viewpoint of environmental load that the above linear low-density polyethylene is a copolymer of ethylene and an α-olefin derived from ethylene. This is because by using ethylene, which is a raw material derived from biomass, it becomes possible to produce it theoretically with 100% components derived from biomass.

[0039] The concentration of ethylene derived from biomass in the above linear low-density polyethylene (hereinafter sometimes referred to as "biomass content") is a value obtained by measuring the content of carbon derived from biomass by radiocarbon ( 14 C) measurement. Since carbon dioxide in the atmosphere contains 14 C at a certain ratio (105.5 pMC), it is known that the 14 C content in plants that take in carbon dioxide in the atmosphere and grow, such as corn, is also about 105.5 pMC. It is also known that fossil fuels contain almost no 14 C. Therefore, by measuring the ratio of 14 C contained in all carbon atoms in linear low-density polyethylene, the ratio of carbon derived from biomass can be calculated. In the present invention, when the content of 14 C in linear low-density polyethylene is P 14C , the content of carbon derived from biomass P bio can be obtained as follows. P bio (%) = P 14C / 105.5 × 100

[0040] In the biomass linear low-density polyethylene used in the present invention, theoretically, if all ethylene derived from biomass and α-olefins derived therefrom are used as raw materials for polyethylene, the concentration of ethylene derived from biomass is 100%, and the biomass content of the linear low-density polyethylene derived from biomass is 100%. Also, the concentration of ethylene derived from biomass in polyethylene derived from fossil fuels produced only from raw materials derived from fossil fuels is 0%, and the biomass content of polyethylene derived from fossil fuels is 0%.

[0041] In the present invention, the biomass linear low-density polyethylene does not necessarily have a biomass content of 100%. This is because even if a raw material derived from biomass is used in part of the biomass linear low-density polyethylene, the amount of fossil fuel used can be reduced compared to the prior art.

[0042] In the biomass linear low-density polyethylene used in the present invention, the polymerization method of the monomer containing ethylene derived from biomass is not particularly limited and can be carried out by a conventionally known method. The polymerization temperature and polymerization pressure may be appropriately adjusted according to the polymerization method and polymerization apparatus. The polymerization apparatus is also not particularly limited, and a conventionally known apparatus can be used. For example, the polymerization method of the monomer containing ethylene described below can be applied.

[0043] The polymerization method of the biomass linear low-density polyethylene can be appropriately selected according to the density of the target linear low-density polyethylene and the difference in branching. For example, as the polymerization catalyst, a multi-site catalyst such as a Ziegler catalyst or a Phillips catalyst, or a single-site catalyst such as a metallocene catalyst is used, and it is preferably carried out in one stage or multiple stages of two or more stages by any method of gas-phase polymerization, slurry polymerization, solution polymerization, and high-pressure ionic polymerization.

[0044] From the viewpoint of obtaining a biomass linear low-density polyethylene having a wide molecular weight distribution and excellent flexibility and moldability, it is preferable to use a multi-site catalyst such as a Ziegler catalyst or a Phillips catalyst. Preferred Ziegler catalysts may be those generally known as Ziegler catalysts for the coordination polymerization of ethylene and α-olefins. For example, they may be catalysts containing a titanium compound and an organoaluminum compound, such as catalysts composed of a titanium halide compound and an organoaluminum compound, and catalysts composed of a solid catalyst component composed of titanium, magnesium, chlorine, etc. and an organoaluminum compound. More specifically, examples of such catalysts include catalysts composed of catalyst component (a) obtained by reacting a reaction product of an alcohol pretreatment product of anhydrous magnesium dihalide and an organometallic compound with a titanium compound and an organometallic compound (b); catalysts composed of catalyst component (A) obtained by reacting magnesium metal with an organic hydroxide compound or an oxygen-containing organic compound such as magnesium, an oxygen-containing organic compound of a transition metal, and an aluminum halide, and catalyst component (B) of an organometallic compound; catalysts composed of a reaction product obtained by reacting (i) at least one member selected from metallic magnesium, an organic hydroxide compound, an oxygen-containing organic compound of magnesium, and a halogen-containing compound, (ii) at least one member selected from an oxygen-containing organic compound and a halogen-containing compound of a transition metal, (iii) a silicon compound, and (iv) a solid catalyst component (A) obtained by reacting an aluminum halide compound and catalyst component (B) of an organometallic compound, etc.

[0045] Also, Phillips catalysts may be those generally known as Phillips catalysts for the coordination polymerization of ethylene and α-olefins. For example, they may be catalyst systems containing a chromium compound such as chromium oxide. Specifically, examples include catalysts in which a chromium compound such as chromium trioxide or a chromium acid ester is supported on a solid oxide such as silica, alumina, silica-alumina, or silica-titania.

[0046] The density of the plant-derived biomass linear low-density polyethylene is not particularly limited, but is preferably 0.905 to 0.935 g / cm 3 More preferably, it is 0.915 to 0.930 g / cm 3 is. There is no particular limitation on the MFR of the plant-derived biomass linear low-density polyethylene, but from the viewpoints of moldability and the like, it is preferably 0.3 to 15.0 g / 10 min, more preferably 1.0 to 12.0 g / 10 min, still more preferably 1.5 to 10.0 g / 10 min, and particularly preferably 2.0 to 9.0 g / 10 min.

[0047] There is no particular limitation on the molecular weight distribution of the plant-derived biomass linear low-density polyethylene, but from the viewpoints of flexibility, moldability and the like, the molecular weight distribution (expressed as the ratio of weight-average molecular weight: Mw, to number-average molecular weight: Mn, Mw / Mn) is preferably 3.5 or more, more preferably 3.8 to 9.0, and still more preferably in the range of 4.0 to 8.6. This Mw / Mn can be measured by gel permeation chromatography (GPC), and more specifically, for example, it can be measured by the method described in the examples of the present application.

[0048] In addition, the plant-derived biomass linear low-density polyethylene has one or more sharp peaks determined from the endothermic curve measured at a heating rate of 10 °C / min by a differential scanning calorimeter (DSC), and the highest temperature of the peak, that is, the melting point is preferably 95 to 140 °C, and more preferably in the range of 100 to 135 °C.

[0049] The plant-derived biomass linear low-density polyethylene may be used alone or in combination of two or more. Further, it may be used together with other polymers such as other ethylene-based polymers (regardless of whether it is plant-derived or not).

[0050] The plant-derived biomass linear low-density polyethylene can be blended with various known additives usually added to olefin polymers, such as antioxidants, weather stabilizers, antistatic agents, antifogging agents, antiblocking agents, slip agents (lubricants), etc., as necessary, within a range not impairing the object of the present invention.

[0051] The laminated film of the present invention has the following (A) heat-sealing layer, (B) intermediate layer, and (C) laminate layer. (A) The heat-sealing layer, (B) the intermediate layer, and (C) the laminate layer all contain the above-mentioned petroleum-derived linear low-density polyethylene. By the fact that (A) the heat-sealing layer, (B) the intermediate layer, and (C) the laminate layer all contain the above-mentioned petroleum-derived linear low-density polyethylene, the lamination strength between the layers can be made sufficient. Also, it is advantageous in terms of the productivity and cost of the laminated film.

[0052] (A) Heat-sealing layer (A) The heat-sealing layer constituting the laminated film of the present invention is often the innermost layer when forming a packaging bag using the laminated film of the present invention and is often fused with other films. For this reason, it is preferable to use a resin with a low melting point so as to obtain high seal strength. For example, by setting the ethylene content of the petroleum-derived linear low-density polyethylene low, the melting point of (A) the heat-sealing layer can be lowered. More specifically, the ethylene content of the petroleum-derived linear low-density polyethylene is preferably 10% by mass or less, more preferably 7% by mass or less, and still more preferably 5% by mass or less.

[0053] When it is necessary to increase the ethylene content of the petroleum-derived linear low-density polyethylene due to the strength of the film and the need to use a material common to other layers, a resin with a low melting point may be added to (A) the heat-sealing layer. Also, when adding plant-derived biomass linear low-density polyethylene to (A) the heat-sealing layer, plant-derived biomass linear low-density polyethylene with a low melting point may be added. Examples of the above-mentioned other low-melting-point resins include relatively low-density ethylene-based polymers such as high-pressure method low-density polyethylene and ethylene·α-olefin random copolymers; tackifying resins such as aliphatic hydrocarbon resins, alicyclic hydrocarbon resins, aromatic hydrocarbon resins, polyterpene resins, rosins, styrene resins, coumarone-indene resins, etc.

[0054] From the viewpoint of heat sealability and the like, the content of petroleum-derived linear low-density polyethylene in the (A) heat-sealing layer is preferably 50% by mass or more, more preferably 55 to 99% by mass, and particularly preferably 65 to 95% by mass.

[0055] (A) There is no particular limitation on the thickness of the heat-sealing layer, but from the viewpoint of heat sealability and the like, it is preferably 5 μm or more, and more preferably 10 μm or more. On the other hand, from the viewpoint of film strength and the like, it is preferably 30 μm or less, and more preferably 20 μm or less. In the heat-sealing layer, various known additives usually added to polyolefins, such as antiblocking agents, slip agents (lubricants), antioxidants, weather stabilizers, antistatic agents, antifogging agents, etc., can be blended as necessary within the range that does not impair the object of the present invention. Examples of the antiblocking agent include silica, talc, silica, clay, calcium carbonate, synthetic zeolite, starch, aluminum oxide, acrylic resin, methacrylic resin, silicone resin, polytetrafluoroethylene resin, etc. Examples of the slip agent include various amides such as palmitic acid amide, stearic acid amide, behenic acid amide, oleic acid amide, erucic acid amide, oleyl palmitamide amide, stearyl palmitamide amide, methylene bis stearyl amide, methylene bis oleyl amide, ethylene bis oleyl amide, ethylene bis erucic acid amide, polyalkylene glycols such as polyethylene glycol and polypropylene glycol, and hydrogenated castor oil.

[0056] (B) Intermediate layer Among the respective layers constituting the laminated film of the present invention, it is preferable that the (A) heat-sealing layer is designed so as to obtain an appropriate seal strength, and the (C) laminate layer is preferably designed in consideration of the laminate strength and the like with the (D) base material layer and the like. On the other hand, since the (B) intermediate layer has relatively few such restrictions, it can be preferentially designed to impart desired physical properties and performance to the entire laminated film of the present invention, such as mechanical properties. In this case, it is preferable that the thickness of the (B) intermediate layer is larger than the thickness of the (A) heat-sealing layer and the thickness of the (C) laminate layer, and it is particularly preferable that the thickness is larger than the sum of the thickness of the (A) heat-sealing layer and the thickness of the (C) laminate layer. More specifically, the thickness of the (B) intermediate layer is preferably 10 μm or more, more preferably 15 μm or more, and particularly preferably 30 μm or more. On the other hand, from the viewpoint of heat sealability and the like, the thickness of the (B) intermediate layer is preferably 150 μm or less, more preferably 130 μm or less, still more preferably 100 μm or less, and 90 μm

[0057] For example, from the viewpoint of realizing high mechanical strength for the entire laminate, it is preferable to use a resin having high mechanical strength at a high ratio in the (B) intermediate layer. For example, as a linear low-density polyethylene derived from petroleum, it is preferable to select one having a high molecular weight and a narrow molecular weight distribution, and further to set its content high. From this viewpoint, the content of the linear low-density polyethylene derived from petroleum in the (B) intermediate layer is preferably 50% by mass or more, more preferably 75 to 100% by mass, still more preferably 85 to 100% by mass, and particularly preferably 90 to 100% by mass. Also, the molecular weight distribution of the linear low-density polyethylene derived from petroleum is preferably 4.0 or less, and particularly preferably 3.0 or less. Similarly, the molecular weight of the linear low-density polyethylene derived from petroleum is preferably 20,000 or more, more preferably 25,000 or more, still more preferably 50,000 or more, and particularly preferably 70,000 or more

[0058] From the viewpoint of improving the flexibility and impact resistance strength of the entire laminate, it is preferable to use a resin with high flexibility and impact resistance strength at a high ratio in the (B) intermediate layer. For example, as a linear low-density polyethylene derived from petroleum, a resin with high flexibility and impact resistance strength can be selected, and its content can be set higher. Also, by adding an elastomer or rubber component to the (B) intermediate layer, the flexibility and impact resistance strength of the (B) intermediate layer can be improved, and the flexibility and impact resistance strength of the entire laminate can be improved. Examples of the elastomer or rubber component at this time include ethylene-propylene copolymer, ethylene-butene copolymer, ethylene-propylene-butene copolymer, etc., and the addition amount can be 1 to 30% by mass, preferably 5 to 10% by mass.

[0059] (C) Laminate layer The (C) laminate layer constituting the laminated film of the present invention can be laminated with other layers including the (D) base layer described later as necessary or desired. Therefore, it is preferable to design the (C) laminate layer in consideration of the laminate strength and the like between it and other layers. From this viewpoint, it is preferable to appropriately select a linear low-density polyethylene derived from petroleum in the (C) laminate layer that has excellent affinity with other layers including the (D) base layer, and its content is preferably 40 to 99% by mass, particularly preferably 70 to 95% by mass. Also, in order to further improve the laminate strength between it and other layers, the surface of the (C) laminate layer (the surface opposite to the surface laminated with the (B) intermediate layer) may be subjected to treatments such as corona treatment and roughening treatment.

[0060] On the other hand, from the viewpoint of preventing blocking when storing the laminated film of the present invention, etc., the (C) laminate layer may contain an anti-blocking agent. As the antiblocking agent, powdery silica, preferably synthetic silica, etc. can be suitably used. From the viewpoint of uniformly dispersing the powdery silica in the (C) laminate layer, the powdery silica is dispersed in a resin having excellent miscibility with the petroleum-derived linear low-density polyethylene constituting the (C) laminate layer, for example, in low-density polyethylene to form a masterbatch, and then the masterbatch may be added to the petroleum-derived linear low-density polyethylene. Further, a slip agent (lubricant) can be blended in the laminate layer as necessary within a range not impairing the object of the present invention. Examples of the slip agent include various amides such as palmitic acid amide, stearic acid amide, behenic acid amide, oleic acid amide, erucic acid amide, oleyl palmitamide amide, stearyl palmitamide amide, methylene bis stearyl amide, methylene bis oleyl amide, ethylene bis oleyl amide, ethylene bis erucic acid amide, etc., polyalkylene glycols such as polyethylene glycol and polypropylene glycol, and hydrogenated castor oil.

[0061] The thickness of the (C) laminate layer is not particularly limited, but from the viewpoint of laminate processability and the like, it is preferably 5 μm or more, and particularly preferably 10 μm or more. On the other hand, from the viewpoint of film strength and the like, it is preferably 30 μm or less, and particularly preferably 20 μm or less.

[0062] Any of the (A) heat-sealing layer, (B) intermediate layer, and (C) laminate layer can be added with various additives and fillers other than petroleum-derived linear low-density polyethylene (and, if present, plant-derived biomass linear low-density polyethylene) as long as it does not contravene the object of the present invention, for example, heat stabilizers, antioxidants, light stabilizers, antistatic agents, antiblocking agents, lubricants, nucleating agents, flame retardants, pigments, dyes, calcium carbonate, barium sulfate, magnesium hydroxide, mica, talc, clay, antibacterial agents, antifogging agents, etc. Furthermore, other thermoplastic resins, thermoplastic elastomers, rubbers, hydrocarbon resins, petroleum resins, etc. may be blended within a range not contravening the object of the present invention.

[0063] Laminated film The laminated film of the present invention has a (A) heat-sealing layer, a (B) intermediate layer, and a (C) laminate layer each containing a linear low-density polyethylene derived from petroleum. In the laminated film of the present invention, preferably, the (C) laminate layer and the (A) heat-sealing layer are laminated via the (B) intermediate layer, but other layers may be present.

[0064] The laminated film of the present invention can be produced by various known film-forming methods, for example, a method in which films to become the (C) laminate layer, the (B) intermediate layer, and the (A) heat-sealing layer are each formed in advance and then the films are bonded together to form a laminated film, a method in which a multilayer die is used to obtain a multilayer film composed of the (B) intermediate layer and the (A) heat-sealing layer, and then the (C) laminate layer is extruded onto the (B) intermediate layer surface to form a laminated film, a method in which a multilayer die is used to obtain a multilayer film composed of the (C) laminate layer and the (B) intermediate layer, and then the (A) heat-sealing layer is extruded onto the (B) intermediate layer surface to form a laminated film, or a method in which a multilayer die is used to obtain a laminated film composed of the (C) laminate layer, the (B) intermediate layer, and the (A) heat-sealing layer.

[0065] Also, as the film-forming method, various known film-forming methods can be adopted, specifically, a T-die casting film-forming method or an inflation film-forming method. The laminated film of the present invention and each layer constituting the same may be an unstretched film (non-stretched film) or a stretched film.

[0066] There is no particular limitation on the thickness of each layer of the laminated film of the present invention, but it is usually in the range of 3 μm or more, preferably 5 to 150 μm, and more preferably 5 to 90 μm. Although the thickness of the laminated film of the present invention is not particularly limited, from the viewpoint of ensuring practical strength, etc., it is usually 20 μm or more, preferably 25 μm or more, more preferably 30 μm or more. On the other hand, from the viewpoint of having practical flexibility even after being laminated with, for example, the (D) base material layer, it is usually 200 μm or less, preferably 180 μm or less, more preferably 150 μm or less.

[0067] The laminated film of the present invention contains 3% by mass or more of plant-derived biomass linear low-density polyethylene in at least one of the (A) heat-sealing layer, (B) intermediate layer, and (C) laminate layer. By containing 3% by mass or more of plant-derived biomass linear low-density polyethylene in at least one of the (A) heat-sealing layer, (B) intermediate layer, and (C) laminate layer, the laminated film of the present invention maintains excellent properties of conventional polyethylene-based laminated films such as mechanical strength and blocking resistance, and realizes a remarkable technical effect that the lamination strength with the (D) base material layer described later is greatly improved. Further, although the lamination strength with multiple layers is greatly improved in this way, surprisingly, the blocking resistance between the laminated films of the present invention can be maintained at the same level as that of conventional products.

[0068] The content of plant-derived biomass linear low-density polyethylene is preferably 6% by mass or more, particularly preferably 12% by mass or more. There is no particular upper limit to the content of plant-derived biomass polyethylene Yes.

[0069] The laminated film of the present invention only needs to contain 3% by mass or more of plant-derived biomass linear low-density polyethylene in at least one of the (A) heat-sealing layer, (B) intermediate layer, and (C) laminate layer. However, since the effect of improving the lamination strength is great, it is particularly preferable to contain 3% by mass or more of plant-derived biomass linear low-density polyethylene in all of the (A) heat-sealing layer, (B) intermediate layer, and (C) laminate layer.

[0070] The content of plant-derived biomass linear low-density polyethylene can be appropriately increased or decreased, for example, by adjusting the formulation of the resin composition when manufacturing each layer. The content of plant-derived biomass linear low-density polyethylene in each layer of the film after production can be measured, for example, by measuring the content of carbon derived from biomass in the film by radiocarbon ( 14 C) measurement, and can be calculated from this measurement result and the content of carbon derived from biomass in the plant-derived biomass linear low-density polyethylene.

[0071] The laminated film of the present invention contains plant-derived biomass linear low-density polyethylene in at least one of (A) the heat-sealing layer, (B) the intermediate layer, and (C) the laminate layer, so that the amount of fossil fuel used in production can be reduced and the environmental load can be reduced. The biomass degree of the laminated film can be calculated by weighted-averaging the biomass degrees of each layer by the weight of each layer. The biomass degree of the laminated film can be appropriately increased or decreased by adjusting the biomass degrees of each layer, and the biomass degree of each layer can be appropriately increased or decreased by adjusting the biomass degree and the amount of use of the resin used in each layer. The biomass degree of the laminated film of the present invention is more preferably 5% by mass or more, and particularly preferably 10% by mass or more. The higher the biomass degree of the laminated film of the present invention, the more preferable it is. Although there is no particular upper limit, from the relationship with the physical properties of the film, cost, etc., it is usually 60% by mass or less, and in many cases 30% by mass or less.

[0072] The heat of fusion ΔH from 0°C to 130°C calculated from the melting curve obtained by DSC measurement of the laminated film of the present invention is preferably 135 to 164 J / g. When the heat of fusion ΔH from 0°C to 130°C is within the above range, the laminate strength between the laminated film and the base material layer can be more effectively improved. Measurement of the melting curve by DSC and calculation of the heat of fusion ΔH from 0°C to 130°C in the melting curve can be performed by a conventionally known method. More specifically, for example, it can be performed by the method described in the examples of the present application. As described above, the heat of fusion ΔH from 0°C to 130°C is preferably 135 to 164 J / g, and particularly preferably 140 to 164 J / g. The heat of fusion ΔH from 0°C to 130°C can be decreased by reducing the crystallinity of the film, such as by adding components other than petroleum-derived linear low-density polyethylene. As components other than petroleum-derived linear low-density polyethylene, it is preferable to add plant-derived biomass polyethylene, ethylene-propylene copolymer, ethylene-butene copolymer, ethylene-propylene-butene copolymer, etc.

[0073] The melting point corresponding to the maximum peak in the melting curve obtained from DSC measurement of the laminated film of the present invention is preferably above 114°C. By being within the above range corresponding to the maximum peak, the lamination strength between the laminated film and the base material layer can be more effectively improved. The above melting point is more preferably 115°C or higher, and particularly preferably 116°C or higher.

[0074] The laminated film of the present invention may be a stretched film or an unstretched film. From the viewpoint of improving mechanical properties, it is preferably a stretched film, and particularly preferably a biaxially stretched film. For biaxial stretching, methods such as sequential biaxial stretching, simultaneous biaxial stretching, and multi-stage stretching are appropriately employed. As the conditions for biaxial stretching, the manufacturing conditions of known biaxially stretched films can be used. For example, in the sequential biaxial stretching method, the longitudinal stretching temperature is in the range of 100°C to 145°C, the stretching ratio is in the range of 4 to 7 times, the transverse stretching temperature is 150 to 190°C, and the stretching ratio is in the range of 8 to 11 times.

[0075] (D) Substrate layer According to the requirement, the laminated film of the present invention can be laminated with a (D) base material layer in its (C) laminate layer. In the present invention, a remarkable effect that the lamination strength with the base material layer (D) at this time is significantly improved is achieved. The lamination strength can be measured by a conventionally known method. More specifically, for example, in the (C) laminate layer of the laminate, after laminating with the (D) base material layer, the sample is cut into strips with a width of 15 mm, and the (D) base material layer and the laminate are peeled off at a tensile speed of 100 mm / min, and it is possible to evaluate by measuring the strength of the tensile peel surface. More specifically, it can be measured by the method described in the examples of the present application. The lamination strength at this time is preferably 3 (N / 15 mm) or more, and particularly preferably 5 (N / 15 mm) or more.

[0076] There is no particular limitation on the (D) base material layer, and for example, a film usually used for plastic packaging bags can be preferably used. Preferred materials for the (D) base material layer include, for example, polyolefins such as crystalline polypropylene, crystalline propylene-ethylene copolymer, crystalline polybutene-1, crystalline poly-4-methylpentene-1, low-, medium-, or high-density polyethylene, ethylene-vinyl acetate copolymer (EVA), ethylene-ethyl acrylate copolymer (EEA), ion-crosslinked olefin copolymer (ionomer); aromatic vinyl copolymers such as polystyrene, styrene-butadiene copolymer; vinyl halide polymers such as polyvinyl chloride, vinylidene chloride resin; nitrile polymers such as acrylonitrile-styrene copolymer, acrylonitrile-styrene-butadiene copolymer; polyamides such as nylon 6, nylon 66, para or metaxylylene adipamide; polyesters such as polyethylene terephthalate (PET), polytetramethylene terephthalate; various polycarbonates; polyacetals such as polyoxymethylene; and plastic films composed of thermoplastic resins. When the contents to be packaged are sensitive to oxygen, a film obtained by vapor-depositing a metal oxide or the like on the above film, or a film coated with an organic compound, or a layer made of ethylene-vinyl alcohol copolymer (EVOH) resin may be provided. Plastic films made of these materials are used in an unstretched, uniaxially stretched, or biaxially stretched state.

[0077] As the (D) base material layer, these plastic films can be used alone or as a laminate of two or more kinds, and can also be formed by laminating one or two or more kinds of these plastic films with a metal foil such as aluminum, paper, cellophane, etc. Preferred (D) base material layers include, for example, single-layer films made of stretched nylon film, stretched polyester film, two-layer films formed by laminating a polyolefin film such as low-density polyethylene or polypropylene with PET, three-layer films formed by laminating PET / nylon / polyethylene, etc. When manufacturing these laminated films, an adhesive or an anchor agent can be interposed between layers as needed. An ink layer for expressing the design may also be provided.

[0078] (D) The method of laminating the base material layer on the (C) laminate layer is not particularly limited. For example, the (D) base material layer can be directly laminated on the (C) laminate layer by extrusion lamination or the like. Also, the (D) base material layer may be laminated on the (C) laminate layer via an adhesive by dry lamination or the like. As the adhesive, ordinary ones such as urethane adhesives, acid-modified polyolefin adhesives, polyester adhesives, polyether adhesives, polyamide adhesives, etc. can be used. (D) The thickness of the base material layer can be arbitrarily set, but usually it is selected from the range of 5 to 50 μm, preferably 10 to 30 μm.

[0079] The laminated film of the present invention and the laminated film obtained by laminating the (D) base material layer on the (C) laminate layer of the laminated film of the present invention are preferably used in various applications, and are particularly suitable for use as a packaging material. When used as a packaging material, heat sealing can be performed between laminated films or between a laminated film and another film in the (A) heat-sealing layer to form a packaging bag. The laminated film obtained by laminating the (D) base material layer on the (C) laminate layer of the laminated film of the present invention has strong lamination strength and rarely peels off during production and use. Therefore, in combination with various (D) base material layers, it is preferably used as a packaging material in a wide range of applications. There are no particular restrictions on the contents to be stored in the packaging bag using the laminated film of the present invention. For example, it is particularly suitable for storing fresh produce, cooked foods, liquid medications, toiletry items such as liquid detergents and fabric softeners, or liquids such as liquid foods like concentrated coffee, as well as powders such as powdered detergents, sugar, pepper, and salt.

Examples

[0080] Hereinafter, the present invention will be specifically described with reference to Examples / Comparative Examples. It should be noted that the present invention is not limited by the following examples in any sense.

[0081] The physical properties and characteristics in the examples / comparative examples were evaluated by the following methods. (1) Molecular weight distribution (Mw / Mn) Under the following conditions, after pretreatment of the polymer sample, the molecular weight was measured by GPC, and the ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) was defined as the molecular weight distribution. i) Pretreatment To 20 mL of the mobile phase for GPC measurement (o-dichlorobenzene), 30 mg of the sample was added, and the mixture was dissolved by shaking at 145 °C. The resulting solution was heat-filtered through a sintered filter with a pore size of 1.0 μm and used for GPC measurement. ii) GPC Apparatus: Gel permeation chromatograph HLC-8321 manufactured by Tosoh Corporation Column: Inner diameter 7.5 mm × 30 cm, 4 columns (TSKgel GMH6-HT: 2 columns, and TSKgel GMH6-HTL: 2 columns) manufactured by Tosoh Corporation ) Column temperature: 140 °C Detector: Differential refractometer Flow rate: 1 mL / min Sampling interval: 0.5 seconds (2) Melting point, heat of fusion Using Q100 manufactured by TA Instruments as a differential scanning calorimeter (DSC), approximately 5 mg of the sample was precisely weighed. In accordance with JIS K7121, under the condition of a nitrogen gas inflow rate of 50 ml / min, the temperature was raised from 25 °C to 200 °C at a heating rate of 10 °C / min to measure the heat melting curve, and from the obtained heat melting curve, the melting point (Tm) and the heat of crystal fusion of the sample were determined.

[0082] (3) Blocking strength In accordance with ASTM D1893-67, the measurement was carried out by overlapping the (A) heat-sealing layers of the laminated film.

[0083] (4) Lamination strength (D) As the base material layer, a nylon film with a thickness of 15 μm (manufactured by Toyobo Co., Ltd., trade name: Hardene) was used. An adhesive (a mixture of Tacklac / Takenate = A310 / A3 manufactured by Mitsui Chemicals, Inc. in ethyl acetate) was applied to the surface of the (C) laminate layer side of the laminate which is the sample, and it was adhered to the (D) base material layer by hand lamination. The sample was cut into strips with a width of 15 mm, and after forming a trigger for peeling between the laminate which is the sample and the (D) base material layer, using a tensilon universal material testing machine (manufactured by A&D Company, Ltd.), the interface between the base material and the sealant was peeled, and the strength of the tensile peel surface was measured at a tensile speed of 100 mm / min, and this was defined as the laminate strength (N / 15 mm).

[0084] (Comparative Example 1) The components constituting each layer were in the formulations shown in Table 1, and were supplied to separate extruders respectively, and a laminated film having an (A) heat-sealing layer, a (B) intermediate layer, and a (C) laminate layer with the resin compositions shown in Table 1 was produced by the T-die method. Since plant-derived biomass linear low-density polyethylene was not used, the biomass content was 0 mass%. Regarding the produced film, evaluations of melting point, heat of fusion, blocking strength, and laminate strength were performed. The results are shown in Table 1.

[0085] (Examples 1 to 8) Except that the resin composition was changed as shown in Table 1, such as using plant-derived biomass linear low-density polyethylene, a laminated film was produced in the same manner as in Comparative Example 1, and evaluations of melting point, heat of fusion, blocking strength, and laminate strength were performed. The results are shown in Table 1.

[0086] The details of each constituent component described by abbreviations in the resin composition column in Table 1 are as follows. ·LLDPE Petroleum-derived linear low-density polyethylene MFR (2.16 kg, 190 °C): 2.3 g / 10 min Density: 918 kg / m 3 Molecular weight distribution (Mw / Mn): 2.52 ·Bio-PE Plant-derived biomass linear low-density polyethylene MFR (2.16 kg, 190 °C): 2.3 g / 10 min Density: 916 kg / m 3 Molecular weight distribution (Mw / Mn): 4.12

[0087]

Table 1

Industrial Applicability

[0088] While maintaining the excellent properties of conventional polyethylene-based laminated films, the laminated film of the present invention has a particularly high practical value, such as a significantly improved lamination strength with the outer layer film and a reduced environmental load in its production, etc. It is particularly suitable for use in applications such as packaging bags and has high applicability in various fields of industries such as agriculture, food processing, distribution, and eating out.

Claims

1. A laminated film (I) having a (A) heat-sealing layer, a (B) intermediate layer, and a (C) laminate layer, each containing a petroleum-derived linear low-density polyethylene, wherein the (C) laminate layer contains 12% by mass or more of a plant-derived biomass linear low-density polyethylene, the heat of fusion ΔH at 0°C to 130°C calculated from the melting curve obtained by DSC measurement of the laminated film (I) is 135 to 164 J / g, the melting point corresponding to the maximum peak in the melting curve obtained by DSC measurement of the laminated film (I) is above 114°C, and the biomass degree of the laminated film composed of the (A) heat-sealing layer, the (B) intermediate layer, and the (C) laminate layer is 5 to 10.2% by mass, the above laminated film (I).

2. Furthermore, the laminated film (I) according to claim 1, wherein the (A) heat-sealing layer and / or the (B) intermediate layer contains at least 3% by mass or more of a plant-derived biomass linear low-density polyethylene.

3. The laminated film (I) according to claim 1 or 2, wherein the molecular weight distribution Mw / Mn of the plant-derived biomass linear low-density polyethylene is 3.5 or more.

4. The laminated film (I) according to any one of claims 1 to 3, having a (D) base material layer on the side of the (C) laminate layer, either directly or via an adhesive layer.

5. A packaging bag comprising the laminated film (I) according to any one of claims 1 to 4.

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