Resin films, laminates and packaging products

Abstract

To provide a resin film which is excellent in opening property of a packaging product while reducing discharge of carbon dioxide by reducing a used amount of a fossil foil.SOLUTION: A resin film is a single layer. The resin film contains linear low density polyethylene and low density polyethylene. The resin film contains biomass-derived polyethylene. The resin film has an area ratio of a region having a molecular weight of 30,000 or less in molecular weight distribution curve obtained from measurement of GPC of the resin film of 12.0% or less with respect to the total peak area according to JIS K 7252-1:2008.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a resin film and a laminate including the same. The present invention also relates to a packaging product including the laminate. [Background technology]

[0002] In recent years, with the growing demand for the creation of a recycling-oriented society, there is a desire to move away from fossil fuels in the materials field, just as there is in energy, and the use of biomass has attracted attention. Biomass is an organic compound that is photosynthesized from carbon dioxide and water, and by using it, it becomes carbon dioxide and water again, making it a so-called carbon-neutral renewable energy. Recently, the practical application of biomass plastics made from these biomass raw materials has progressed rapidly, and attempts are being made to produce various resins from biomass raw materials.

[0003] As a biomass-derived resin, polylactic acid (PLA), which is produced via lactic acid fermentation, was the first to be commercially produced, but since its performance as a plastic differs significantly from current general-purpose plastics, including its biodegradability, there are limitations to its product applications and manufacturing methods, and it has not yet become widely used.In addition, a life cycle assessment (LCA) is being conducted on PLA, and discussions are being held on the energy consumption during PLA production and its equivalence when replacing general-purpose plastics.

[0004] Here, various types of general-purpose plastics are used, such as polyethylene, polypropylene, polyvinyl chloride, polystyrene, and polyester. In particular, polyethylene is molded into films, sheets, bottles, and the like, and is used in various applications such as packaging materials, and is used in large quantities around the world. Therefore, using conventional polyethylene derived from fossil fuels places a large burden on the environment. For this reason, it is desirable to use raw materials derived from biomass in the production of polyethylene to reduce the amount of fossil fuel used. For example, research has been conducted to date on the production of ethylene and butylene, which are raw materials for polyolefin resins, from renewable natural raw materials (see Patent Document 1).

[0005] For example, Patent Document 2 discloses a resin film made of a resin composition containing a carbon-neutral polyolefin, which contains a biomass-derived polyolefin obtained by polymerizing a monomer containing ethylene derived from biomass, and has a molecular weight of 0.91 to 0.96 g / cm. 3 (910kg / m 3 ~960kg / m 3 The document discloses a resin film made of a resin composition characterized by having a density of 1000 nm or less. The document also discloses that the mechanical properties of the resin film are comparable to those of resin films made from conventional raw materials obtained from fossil fuels. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Special Publication No. 2011-506628 [Patent Document 2] Special Publication No. 2012-251006 Summary of the Invention [Problem to be solved by the invention]

[0007] In the manufacturing process of a packaged product such as a packaging bag, the inner surfaces of the laminate are heat-sealed so that a part of the outer edge of the packaged product remains as an opening. Next, the contents are filled into the bag through the opening. After that, the opening is sealed by heat sealing. In this manner, a packaged product containing the contents can be obtained. At this time, in order to increase the productivity of the packaged product, it is necessary that the contents can be easily filled. Therefore, it is important that the opening can be easily opened (openability) after the inner surfaces of the laminate are heat-sealed. The resin film disclosed in Patent Document 2 is also used as a sealant layer on the inner surface of such a packaged product, but there is room for improvement in the openability of the packaged product.

[0008] The present inventors have found that the above problem can be solved by reducing the content of low molecular weight components in the resin film to a certain amount or less. The present inventors have also found that the above problem can be solved by specifying the type of biomass-derived polyethylene contained in the resin film.

[0009] Therefore, an object of the present invention is to provide a resin film that is excellent in opening properties for packaging products while reducing the amount of fossil fuel used and thereby reducing carbon dioxide emissions. [Means for solving the problem]

[0010] The present invention is a single-layer resin film, comprising a linear low-density polyethylene and a low-density polyethylene, wherein the resin film comprises biomass-derived polyethylene, and an area ratio of a region having a molecular weight of 30,000 or less in a molecular weight distribution curve obtained by GPC measurement of the resin film in accordance with JIS K 7252-1:2008 is 12.0% or less of a total peak area.

[0011] The present invention is a single-layer resin film, which contains linear low-density polyethylene and low-density polyethylene, and which contains biomass-derived polyethylene and does not contain biomass-derived linear low-density polyethylene.

[0012] In the resin film according to the present invention, the biomass ratio may be 5% or more.

[0013] In the resin film according to the present invention, the dispersity may be 5.0 or less.

[0014] The present invention is a laminate comprising the above-mentioned resin film and a base layer.

[0015] The present invention is a packaging product comprising the laminate described above.

[0016] In the packaging product according to the present invention, the resin film may be located on the innermost surface of the packaging product. Effect of the Invention

[0017] According to the present invention, it is possible to provide a resin film that is excellent in opening properties for packaging products while reducing the amount of fossil fuel used and thereby reducing carbon dioxide emissions. Packaging products using such a resin film have excellent suitability for filling contents. [Brief description of the drawings]

[0018] [Figure 1] FIG. 1 is a cross-sectional view showing an example of a resin film of the present invention. [Diagram 2] FIG. 1 is a cross-sectional view showing an example of a laminate of the present invention. [Diagram 3] FIG. 1 is a diagram showing an example of a packaging container including a laminate of the present invention. [Figure 4] FIG. 2 is a diagram showing the configurations of resin films in Examples 1 and 2 and Comparative Examples 1 and 2, as well as the results of GPC measurement and openability. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] (Resin film) Fig. 1 is a cross-sectional view showing an example of the resin film 10 of the present invention. As shown in Fig. 1, the resin film 10 is a single layer.

[0020] The resin film contains linear low-density polyethylene and low-density polyethylene. By containing linear low-density polyethylene, the seal strength and impact resistance such as drop strength of the resin film can be improved. In addition, by containing low-density polyethylene, the tearability of the resin film can be improved.

[0021] Here, we will explain low-density polyethylene (LDPE) and linear low-density polyethylene (LLDEP). Low-density polyethylene is a high-pressure ethylene homopolymer, which can be obtained by a conventionally known high-pressure radical polymerization method. Linear low-density polyethylene is a copolymer of ethylene and an α-olefin polymerized using a multi-site catalyst, such as a Ziegler-Natta catalyst, or a single-site catalyst, such as a metallocene catalyst. Both have a density of 930 kg / m 3 It refers to one having a density of less than 1000 nm. Examples of α-olefins that serve as comonomers for linear low-density polyethylene include α-olefins having 3 to 20 carbon atoms, such as propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-nonene, 4-methylpentene, and mixtures thereof. Here, the density of polyethylene is a value measured according to the method specified in Method A of JIS K7112-1980 after annealing as described in JIS K6760-1995.

[0022] The single-site catalyst is a catalyst capable of forming a uniform active species, and is usually prepared by contacting a metallocene transition metal compound or a nonmetallocene transition metal compound with an activating cocatalyst. Compared with a multi-site catalyst, a single-site catalyst is preferred because it has a uniform active site structure and can polymerize a polymer with a high molecular weight and a highly uniform structure. As the single-site catalyst, it is particularly preferred to use a metallocene catalyst. The metallocene catalyst is a catalyst containing each catalyst component of a transition metal compound of Group IV of the periodic table containing a ligand having a cyclopentadienyl skeleton, a cocatalyst, and if necessary, an organometallic compound and a carrier.

[0023] In the above-mentioned transition metal compound of Group IV of the periodic table containing a ligand having a 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 a hydrocarbon group having 1 to 30 carbon atoms, a silyl group, a silyl-substituted alkyl group, a silyl-substituted aryl group, a cyano group, a cyanoalkyl group, a cyanoaryl group, a halogen group, a haloalkyl group, a halosilyl group, 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 azulenyl ring, or a hydrogenated product thereof. The rings formed by bonding the substituents to each other may further have substituents.

[0024] In the transition metal compound of Group IV of the periodic table containing a ligand having a cyclopentadienyl skeleton, the transition metal may be 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 preferred that the ligands having each cyclopentadienyl skeleton are bonded to each other by a bridging group. The bridging group may be an alkylene group having 1 to 4 carbon atoms, a silylene group, a substituted silylene group such as a dialkylsilylene group or a diarylsilylene group, or a substituted germylene group such as a dialkylgermylene group or a diarylgermylene group. The substituted silylene group is preferred.

[0025] In the transition metal compound of Group IV of the periodic table, representative ligands other than those having a cyclopentadienyl skeleton include hydrogen, hydrocarbon groups having 1 to 20 carbon atoms (such as alkyl groups, alkenyl groups, aryl groups, alkylaryl groups, aralkyl groups, and polyenyl groups), halogens, metaalkyl groups, and metaaryl groups.

[0026] The above-mentioned compounds of transition metals of Group IV of the periodic table containing a ligand having a cyclopentadienyl skeleton can be used as the catalyst component either alone or in combination of two or more kinds.

[0027] The co-catalyst refers to a catalyst that can effectively use the above-mentioned transition metal compound of Group IV of the periodic table as a polymerization catalyst or balance the ionic charge in a catalytically activated state. Examples of the co-catalyst include benzene-soluble aluminoxanes of organoaluminum oxy compounds and benzene-insoluble organoaluminum oxy compounds, ion-exchangeable layered silicates, boron compounds, ionic compounds consisting of cations containing or not containing active hydrogen groups and non-coordinating anions, lanthanoid salts such as lanthanum oxide, tin oxide, and phenoxy compounds containing a fluoro group.

[0028] The transition metal compound of Group IV of the periodic table containing a ligand having a cyclopentadienyl skeleton may be used supported on an inorganic or organic carrier, preferably an inorganic or organic porous oxide, and specific examples of the carrier include ion-exchangeable layered silicates such as montmorillonite, SiO2, Al2O3, MgO, ZrO2, TiO2, B2O3, CaO, ZnO, BaO, ThO2, and mixtures thereof.

[0029] Furthermore, examples of organometallic compounds that may be used as necessary include organoaluminum compounds, organomagnesium compounds, organozinc compounds, etc. Of these, organoaluminum compounds are preferably used.

[0030] The content of the linear low-density polyethylene is preferably 30% by mass or more and 95% by mass or less, more preferably 40% by mass or more and 90% by mass or less, and even more preferably 50% by mass or more and 85% by mass or less, which can further improve the opening property of the packaged product and the seal strength and impact resistance such as drop strength of the resin film.

[0031] The content of the low-density polyethylene is preferably 5% by mass or more and 70% by mass or less, more preferably 10% by mass or more and 60% by mass or less, and even more preferably 15% by mass or more and 50% by mass or less, which can further improve the opening property of the packaged product and the tearing property of the resin film.

[0032] The low density polyethylene and linear low density polyethylene preferably have a melt flow rate (MFR) of 0.1 g / 10 min to 10 g / 10 min, more preferably 0.2 g / 10 min to 9 g / 10 min, and even more preferably 1 g / 10 min to 8.5 g / 10 min. The melt flow rate is a value measured by the A method under the conditions of a temperature of 190° C. and a load of 21.18 N in the method specified in JIS K7210-1995. If the MFR is 0.1 g / 10 min or more, the extrusion load during molding can be reduced. Also, if the MFR is 10 g / 10 min or less, the mechanical strength of the resin film can be increased.

[0033] The resin film may contain high density polyethylene (HDPE) or medium density polyethylene (MDPE) as long as the object of the present invention is not impaired. 3 More than 942kg / m 3 High density polyethylene refers to polyethylene having a density of less than 942 kg / m 3 This refers to polyethylene having a density of 100 or more.

[0034] The resin film contains polyethylene derived from biomass. The resin film preferably has a biomass ratio, which will be described below, of 5% or more, more preferably 10% to 95%, and even more preferably 15% to 60%. If the biomass ratio is within the above range, the amount of fossil fuel used can be reduced, and the environmental load can be reduced. Unless otherwise specified, the "biomass ratio" refers to the weight ratio of biomass-derived components.

[0035] <Biomass-derived ethylene> The method for producing biomass-derived ethylene, which is a raw material for biomass-derived polyethylene (hereinafter also referred to as biomass polyethylene), is not particularly limited, and it can be obtained by a conventionally known method. An example of the method for producing biomass-derived ethylene will be described below.

[0036] Biomass-derived 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 a plant raw material. The plant raw material is not particularly limited, and any conventionally known plant can be used. Examples of the plant raw material include corn, sugarcane, beet, and manioc.

[0037] Fermented ethanol derived from biomass refers to ethanol produced by contacting a culture solution containing a carbon source obtained from a plant raw material with an ethanol-producing microorganism or a product derived from the crushed microorganism, and then purifying the ethanol. Conventionally known methods such as distillation, membrane separation, and extraction can be applied to purify ethanol from the culture solution. For example, there is a method of adding benzene, cyclohexane, etc., and removing water by azeotropy or membrane separation.

[0038] In order to obtain the above ethylene, the ethanol may be further subjected to advanced purification at this stage, for example, so that the total amount of impurities in the ethanol is reduced to 1 ppm or less.

[0039] A catalyst is usually used when obtaining ethylene by the dehydration reaction of ethanol, but the catalyst is not particularly limited and any conventionally known catalyst can be used. From the viewpoint of the process, a fixed bed flow reaction is advantageous because it is easy to separate the catalyst from the product, and for example, γ-alumina is preferable.

[0040] This dehydration reaction is an endothermic reaction, and is therefore usually carried out under heating conditions. As long as the reaction proceeds at a commercially useful reaction rate, the heating temperature is not limited, but is preferably 100° C. or higher, more preferably 250° C. or higher, and even more preferably 300° C. or higher. There is no particular upper limit, but from the viewpoint of energy balance and equipment, it is preferably 500° C. or lower, more preferably 400° C. or lower.

[0041] In the dehydration reaction of ethanol, the yield of the reaction depends on the amount of water contained in the ethanol supplied as a raw material. In general, when performing a dehydration reaction, it is preferable to have no water in consideration of the efficiency of removing water. However, in the case of the dehydration reaction of ethanol using a solid catalyst, it has been found that the amount of other olefins, especially butene, produced tends to increase if water is not present. It is presumed that this is because ethylene dimerization after dehydration cannot be suppressed if a small amount of water is not present. The lower limit of the allowable water content is 0.1% by mass or more, preferably 0.5% by mass or more. The upper limit is not particularly limited, but from the viewpoint 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.

[0042] By carrying out the dehydration reaction of ethanol in this manner, a mixture of ethylene, water, and a small amount of unreacted ethanol is obtained, but since ethylene is in a gaseous state at room temperature under about 5 MPa or less, water and ethanol can be removed from the mixture by gas-liquid separation to obtain ethylene. This method may be performed by a known method.

[0043] The ethylene obtained by the gas-liquid separation is further distilled. The distillation method, operation temperature, residence time, etc. are not particularly limited, except that the operation pressure at this time is normal pressure or higher.

[0044] When the raw material is biomass-derived ethanol, the obtained ethylene contains trace amounts of carbonyl compounds such as ketones, aldehydes, and esters, which are impurities mixed in during 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 enzyme decomposition products and impurities, as well as ammonia, which is a decomposition product thereof. Depending on the use of ethylene, these trace amounts of impurities may be problematic, so they may be removed by purification. The purification method is not particularly limited, and can be performed by a conventionally known method. An example of a suitable purification operation is an adsorption purification method. The adsorbent 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 ethanol.

[0045] In addition, a caustic water treatment may be used in combination as a method for purifying impurities in ethylene. When caustic water treatment is used, it is preferable to carry out the treatment before adsorption purification. In that case, it is necessary to carry out a water removal treatment after the caustic treatment and before the adsorption purification.

[0046] <Biomass polyethylene> Biomass polyethylene is obtained by polymerizing monomers containing ethylene derived from biomass. It is preferable to use the ethylene derived from biomass obtained by the above-mentioned production method. Since ethylene derived from biomass is used as the raw material monomer, the polymerized polyethylene is derived from biomass. When the biomass polyethylene is a low-density polyethylene derived from biomass, it is polyethylene polymerized by the above-mentioned polymerization method using ethylene derived from biomass. Note that the raw material monomer for polyethylene does not have to contain 100% by mass of ethylene derived from biomass.

[0047] As long as the object of the present invention is not impaired, the monomer that is the raw material of the biomass polyethylene may further contain ethylene derived from a fossil fuel.

[0048] The biomass-derived ethylene concentration in the polyethylene (hereinafter sometimes referred to as "biomass degree") is a value measured by measuring the amount of carbon derived from biomass by radioactive carbon (C14) measurement. Carbon dioxide in the atmosphere contains a certain proportion of C14 (105.5 pMC), and it is known that the C14 content in plants that grow by absorbing carbon dioxide from the atmosphere, such as corn, is also about 105.5 pMC. It is also known that fossil fuels contain very little C14. Therefore, by measuring the proportion of C14 in the total carbon atoms in the polyethylene, the proportion of carbon derived from biomass can be calculated, and the weight ratio of the biomass-derived component can be obtained.

[0049] In the present invention, theoretically, if all biomass-derived ethylene is used as the raw material for polyethylene, the concentration of biomass-derived ethylene is 100%, and the biomass degree of biomass polyethylene is 100%. Also, the concentration of biomass-derived ethylene in fossil fuel-derived polyethylene produced only from raw materials derived from fossil fuel is 0%, and the biomass degree of fossil fuel-derived polyethylene is 0%.

[0050] In the present invention, the biomass polyethylene or the biomass-derived resin layer does not need to have a biomass content of 100%. This is because if even a part of the resin film is made of biomass-derived raw materials, it is in line with the purpose of the present invention, which is to reduce the amount of fossil fuel used compared to conventional methods.

[0051] In one embodiment, the resin film is subjected to GPC (gel permeation chromatography) measurement in accordance with JIS K 7252-1:2008 (Plastics - Determination of average molecular weight of polymer by size exclusion chromatography). The area ratio of the region of molecular weight of 30,000 or less in the molecular weight distribution curve obtained from the measurement is 12.0% or less of the total peak area (distribution area). Components with molecular weight of 30,000 or less (hereinafter also referred to as low molecular weight components) contained in the resin film have adhesiveness, and the low molecular weight components of the resin film reduce the opening property of the packaged product in the manufacturing process of the packaged product. By making the area ratio of the region of molecular weight of 30,000 or less of the resin film 12.0% or less of the total peak area, that is, by making the content of low molecular weight components of the resin film 12.0% or less by mass, it is possible to suppress adhesion due to low molecular weight components and improve the opening property of the packaged product. The area ratio of the region of the resin film having a molecular weight of 30,000 or less is preferably 10.5% or less of the total peak area, and more preferably 10.0% or less, from the viewpoint of further improving the opening property of the packaged product.

[0052] The GPC measurement of the resin film can be performed by any other general method as long as it complies with JIS K 7252-1:2008, but it is preferable to use an HLC (registered trademark)-8321 GPC / HT type high temperature gel permeation chromatograph (manufactured by Tosoh Corporation) as the gel permeation chromatograph, two TSKgel GMH6-HT (ID 7.5 mm × 300 mm) columns + two TSKgel GMH6-HTL (ID 7.5 × 300 mm) columns (manufactured by Tosoh Corporation) as the columns, and o-dichlorobenzene (containing 0.025 mass % dibutylhydroxytoluene (BHT)) as the mobile phase at a column temperature of 140°C.

[0053] The resin film may contain linear low-density polyethylene derived from fossil fuels. This can further improve the opening property. The resin film may also contain low-density polyethylene derived from biomass. This can further reduce the amount of fossil fuel used.

[0054] In another embodiment, the resin film does not contain linear low density polyethylene derived from biomass. This can improve the opening property of the packaged product. Furthermore, the resin film is preferably made of low density polyethylene derived from biomass and linear low density polyethylene or low density polyethylene derived from fossil fuel, and more preferably made of low density polyethylene derived from biomass and linear low density polyethylene derived from fossil fuel. This can further improve the opening property of the packaged product.

[0055] The polydispersity of the resin film (weight average molecular weight Mw / number average molecular weight Mn) is preferably 5.0 or less, more preferably 4.5 or less, and even more preferably 4.0 or less, which can further improve the opening property of the packaged product.

[0056] The thickness of the resin film is preferably from 10 to 200 μm, more preferably from 20 to 170 μm, and further preferably from 30 to 150 μm.

[0057] (Method of manufacturing resin film) The method for producing the resin film of the present invention is not particularly limited, and the film can be produced by a conventionally known method. The resin film is preferably produced by extrusion molding, and the extrusion molding is more preferably performed by a T-die method or an inflation method.

[0058] For example, a resin film can be formed by extrusion molding in the following manner. After drying the linear low-density polyethylene and the low-density polyethylene, they are fed to a melt extruder heated to a temperature (Tm) to Tm+70° C. above their melting points, melted, and extruded into a sheet from a die such as a T-die, and the extruded sheet is quenched and solidified on a rotating cooling drum or the like to form a resin film. As the melt extruder, a single-screw extruder, a twin-screw extruder, a vent extruder, a tandem extruder, or the like can be used depending on the purpose.

[0059] (Laminate) Fig. 2 is a cross-sectional view showing an example of the laminate 20 of the present invention. As shown in Fig. 2, the laminate 20 includes the above-mentioned resin film 10 and a base layer 21. By providing the laminate with the above-mentioned resin film, the opening property of the packaged product can be improved. In addition, the above-mentioned resin film may constitute at least one outermost layer of the laminate.

[0060] (base material layer) The base layer includes at least one resin material, such as polyesters including polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), 1,4-polycyclohexylene dimethylene terephthalate, and terephthalic acid-cyclohexane dimethanol-ethylene glycol copolymers, polyamides including nylon 6 and nylon 6,6, polyolefins including polyethylene (PE), polypropylene (PP), and polymethylpentene, vinyl resins including polyvinyl chloride, polyvinyl alcohol (PVA), polyvinyl acetate, vinyl chloride-vinyl acetate copolymers, polyvinyl butyral, and polyvinylpyrrolidone (PVP), (meth)acrylic resins including polyacrylate, polymethacrylate, and polymethyl methacrylate, cellulose resins including cellophane, cellulose acetate, nitrocellulose, cellulose acetate propionate (CAP), and cellulose acetate butyrate (CAB), styrene resins including polystyrene (PS), and chlorinated resins thereof. Among these, polyolefin, polyester and polyamide are preferred, and polypropylene, polyethylene terephthalate, nylon 6 and nylon 6,6 are more preferred. In the present invention, "(meth)acrylic" means to include both "acrylic" and "methacrylic", and "(meth)acrylate" means to include both "acrylate" and "methacrylate".

[0061] The base layer may contain additives such as fillers, plasticizers, antistatic agents, UV absorbers, inorganic particles, organic particles, release agents, and dispersants, as long as the additives do not impair the properties of the present invention.

[0062] The base layer may be a film containing the above-mentioned resin material, and the film may be a stretched film or an unstretched film. From the viewpoint of strength, however, a stretched film that is uniaxially or biaxially stretched is preferable.

[0063] (Other layers) The laminate may have at least one other layer in addition to the above layers. When the laminate has two or more other layers, each of the other layers may have the same composition or different compositions. The other layers can be formed on the base layer or the resin film. Examples of the other layers include a printed layer and an adhesive layer. The printed layer can be formed using a conventionally known pigment or dye, and the method of forming the printed layer is not particularly limited. The adhesive layer is an adhesive layer or an adhesive resin layer formed to bond any two layers together by lamination.

[0064] For example, one- or two-liquid type cured or non-cured vinyl, (meth)acrylic, polyamide, polyester, polyether, polyurethane, epoxy, rubber, and other solvent-based, water-based, or emulsion-based laminating adhesives can be used as the adhesive layer. Coating methods for the above adhesives include, for example, direct gravure roll coating, gravure roll coating, kiss coating, reverse roll coating, Fountain, transfer roll coating, and other methods. The coating amount is 0.1 g / m 2 ~10g / m 2 (dry state) is preferable, and 1g / m 2 ~5g / m 2 (Dry state) is more preferable.

[0065] The adhesive resin layer may contain a thermoplastic resin. The adhesive resin layer can be formed by a conventionally known method, for example, a melt extrusion lamination method or a sand lamination method. As a material for the adhesive resin layer, a polyolefin resin such as a polyethylene resin or a polypropylene resin, or a cyclic polyolefin resin, or a copolymer resin, modified resin, or mixture (including alloy) containing these resins as main components can be used. Examples of polyolefin resins include low-density polyethylene (LDPE), medium-density polyethylene (MDPE), high-density polyethylene (HDPE), linear low-density polyethylene (LLDPE), polypropylene (PP), ethylene-α-olefin copolymers polymerized using a metallocene catalyst, random or block copolymers of ethylene-polypropylene, ethylene-vinyl acetate copolymer (EVA), ethylene-acrylic acid copolymer (EAA), ethylene-ethyl acrylate copolymer (EEA), ethylene-methacrylic acid copolymer (EMAA), ethylene-methyl methacrylate copolymer (EMMA), ethylene-maleic acid copolymer, ionomer resins, and acid-modified polyolefin resins obtained by modifying the above-mentioned polyolefin resins with unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid, maleic anhydride, fumaric acid, and itaconic acid in order to improve adhesion between layers. In addition, resins obtained by graft-polymerizing or copolymerizing unsaturated carboxylic acids, unsaturated carboxylic anhydrides, and ester monomers with polyolefin resins can be used. These materials can be used alone or in combination of two or more. Examples of cyclic polyolefin resins that can be used include cyclic polyolefins such as ethylene-propylene copolymers, polymethylpentene, polybutene, and polynorbornene. These resins can be used alone or in combination of two or more.

[0066] The adhesive resin layer may contain a material derived from biomass or a material derived from fossil fuels.

[0067] (Method of manufacturing laminate) The method for producing the laminate is not particularly limited, and the laminate can be produced by a conventionally known method such as melt extrusion lamination, dry lamination, sand lamination, etc. For example, the laminate can be produced by extruding a resin film onto a substrate layer by the melt extrusion lamination method.

[0068] (packaged products) The packaged product includes the laminate. The packaged product may be one in which the resin film is located on the innermost surface of the packaged product. The innermost surface is the surface of the packaged product that is located on the side of the contents contained in the packaged product.

[0069] The shape of the packaged product is not particularly limited, and may be a shape of a packaging bag 30 (stand-up pouch) as shown in Fig. 3. In the packaging bag 30, only the body 31 may be formed of the laminate, only the bottom 32 may be formed of the laminate, or both the body 31 and the bottom 32 may be formed of the laminate.

[0070] The packaging bag 30 can be manufactured by heat sealing the laminate into a cylindrical shape with the resin film facing inside to form a body 31, and then folding another laminate into a V shape with the resin film facing inside the packaging bag 30, sandwiching one end of the body 31, and heat sealing to form a bottom 32. In Fig. 3, the shaded areas indicate the heat-sealed areas.

[0071] The heat sealing method is not particularly limited, and can be performed by known methods such as bar sealing, rotary roll sealing, belt sealing, impulse sealing, high frequency sealing, ultrasonic sealing, etc.

[0072] The contents filled in the packaged product are not particularly limited, and may be liquid, powder, or gel. In addition, the contents may be food or non-food. After filling the contents, the opening is heat sealed. EXAMPLES

[0073] Next, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the description of the following examples as long as it does not depart from the gist of the present invention.

[0074] (GPC measurement conditions) Apparatus: HLC (registered trademark)-8321GPC / HT type high temperature gel permeation chromatograph (manufactured by Tosoh Corporation) Column: TSKgel GMH6-HT (ID 7.5 mm x 300 mm) x 2 + TSKgel GMH6-HTL (ID 7.5 x 300 mm) x 2 (Tosoh Corporation) Column temperature: 140℃ Mobile phase: o-dichlorobenzene (containing 0.025% by mass of dibutylhydroxytoluene (BHT)) ·Flow rate: 1.0mL / min. Sample concentration: 0.10% (W / V) ·Injection volume: 0.4mL Detector: Differential refractometer (RI) Column calibration: Standard polystyrene (monodisperse polystyrene, Tosoh Corporation) Molecular weight calibration: Simple polystyrene equivalent

[0075] [Example 1] As component 1 and component 2, 20 parts by mass of biomass-derived low-density polyethylene (Bio-LDPE, manufactured by Braskem, product name: SEB-853, density: 923 kg / m 3 , MFR: 2.7 g / 10 min, biomass content: 95%), and 80 parts by mass of linear low-density polyethylene derived from fossil fuels (petroleum-based LLDPE, manufactured by Ube Maruzen Polyethylene Co., Ltd., product name: Yumerit (registered trademark) 770FT, density: 918 kg / m 3 The mixture was melted and kneaded to produce a single-layer resin film using a T-die film molding machine. The biomass ratio was 19%.

[0076] 20 mg of the resin film was cut out, added to 20 mL of o-dichlorobenzene (containing 0.025% by mass of BHT), and boiled at 145°C to dissolve the resin film. This was hot filtered through a sintered filter with a pore size of 1.0 μm to obtain a filtrate. This filtrate was measured under the above-mentioned GPC measurement conditions. The area ratio of the region with a molecular weight of 30,000 or less obtained was 9.4%. The degree of dispersion of the resin film was 3.5.

[0077] Next, a laminate including the resin film of this example and a base layer was prepared, and a packaging bag having an opening was prepared using this laminate so that the resin film was located on the innermost surface. The opening of the packaging bag could be opened very easily. Such a packaging bag has excellent suitability for filling the contents.

[0078] [Example 2] A resin film was produced and GPC was measured in the same manner as in Example 1, except that 40 parts by mass of biomass-derived low-density polyethylene and 60 parts by mass of fossil fuel-derived linear low-density polyethylene were used as component 1 and component 2, respectively. The area ratio of the resin film having a molecular weight of 30,000 or less was 11.8%, and the degree of dispersion was 4.2. The biomass degree was 38%.

[0079] Next, a laminate including the resin film of this example and a base layer was prepared, and a packaging bag having an opening was prepared using this laminate so that the resin film was located on the innermost surface. The opening of the packaging bag could be easily opened. Such a packaging bag has excellent suitability for filling the contents.

[0080] [Comparative Example 1] As component 1 and component 2, 20 parts by mass of biomass-derived low-density polyethylene and 80 parts by mass of biomass-derived linear low-density polyethylene (Bio-LLDPE, manufactured by Braskem, product name: SLL-118, density: 916 kg / m 3A resin film was produced and GPC measurements were performed in the same manner as in Example 1, except that a polymer having a molecular weight of 30,000 or less was used. The area ratio of the region having a molecular weight of 30,000 or less was 12.7%, the dispersity was 6.0, and the biomass degree was 69.6%.

[0081] Next, a laminate including the resin film of this comparative example and a base layer was produced, and a packaging bag having an opening was produced using this laminate so that the resin film was located on the innermost surface. The opening of the packaging bag was stuck and could not be easily opened.

[0082] [Comparative Example 2] As component 1, 20 parts by mass of fossil fuel-derived low-density polyethylene (petrol LDPE, manufactured by Ube Maruzen Polyethylene Co., Ltd., product name: F224N, density: 0.924 kg / m 3 Except for using a polymer having a molecular weight of 30,000 or less, MFR of 2.0 and a biomass content of 0%, a resin film was produced and GPC measurement was performed in the same manner as in Example 1. The area ratio of the region having a molecular weight of 30,000 or less in this resin film was 8.5%.

[0083] Next, a laminate was produced that included the resin film of this comparative example and a base layer, and a packaging bag having an opening was produced using this laminate so that the resin film was located on the innermost surface. The opening of the packaging bag could be opened very easily.

[0084] FIG. 4 shows the results of Examples 1 and 2 and Comparative Examples 1 and 2. [Explanation of symbols]

[0085] 10: Resin film 20: Laminate 21: Base material layer 30: Packaging bag 31: Torso 32: Bottom

Claims

1. A single-layer resin film, the resin film contains linear low-density polyethylene and low-density polyethylene, The resin film contains biomass-derived polyethylene, the area ratio of a region having a molecular weight of 30,000 or less in a molecular weight distribution curve obtained by GPC measurement of the resin film in accordance with JIS K 7252-1:2008 is 12.0% or less of a total peak area; The resin film has a thickness of 20 μm or more and 200 μm or less.

2. The resin film according to claim 1 , having a biomass ratio of 5% or more.

3. The resin film according to claim 1 or 2, having a degree of dispersion of 5.0 or less.

4. A laminate comprising the resin film according to any one of claims 1 to 3 and a base layer.

5. A packaging product comprising the laminate of claim 4.

6. The packaging product according to claim 5 , wherein the resin film is located on the innermost surface of the packaging product.

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