Packaging material, and packaging product

Abstract

To provide a packaging material by which influence of a biomass component-specific odor imparted to a content of a packaging product is suppressed, while reducing a use amount of fossil fuel.SOLUTION: A cup container uses a packaging material obtained by laminating a first polyolefin resin layer, a paper base material layer, and a sealant layer in this order for a trunk material and a bottom material. The first polyolefin resin layer is located on an outermost face of the cup container. The first polyolefin resin layer is a low-density polyethylene resin layer derived from biomass. The sealant layer is a second polyolefin resin layer located on an innermost face of the cup container. The second polyolefin resin layer is a low-density polyethylene resin layer or a straight-chain low-density polyethylene resin layer derived from fossil fuel.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to packaging materials that include biomass-derived components and packaged products that include the packaging materials. [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] Patent Document 2 proposes a paper cup as a product using raw materials derived from biomass. This is characterized in that the inner surfaces of the body member blank and bottom member blank that form the body member and bottom member of the paper cup are inner thermoplastic resin layers made of biomass polyethylene resin derived from plants. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Special Publication No. 2011-506628 [Patent Document 2] JP 2015-214365 A Summary of the Invention [Problem to be solved by the invention]

[0007] However, when a resin made of a biomass-derived component is used on the innermost surface of a packaging product as proposed in Patent Document 2, there is a problem that the odor specific to the biomass component affects the contents. The present inventors have discovered that the above problem can be solved by providing a layer made of a fossil fuel-derived component on the innermost surface of the packaging material in a packaging product formed from the packaging material.

[0008] Therefore, an object of the present invention is to provide a packaging material that uses raw materials derived from biomass, reduces the amount of fossil fuel used, and suppresses the effect of the odor specific to biomass components on the contents of the packaged product. [Means for solving the problem]

[0009] The present invention is a cup container whose body and bottom are made of a packaging material in which a first polyolefin resin layer, a paper base layer, and a sealant layer are laminated in that order, wherein the first polyolefin resin layer is located on the outermost surface of the cup container, the first polyolefin resin layer being a biomass-derived low-density polyethylene resin layer, and the sealant layer is a second polyolefin resin layer located on the innermost surface of the cup container, and the second polyolefin resin layer is a fossil fuel-derived low-density polyethylene resin layer or a linear low-density polyethylene resin layer.

[0010] In the cup container according to the present invention, the second polyolefin resin layer may be in contact with the paper base layer.

[0011] The present invention is a paper container for liquids that uses a packaging material in which a first polyolefin resin layer, a paper base layer, and a sealant layer are laminated in that order, wherein the first polyolefin resin layer is located on the outermost surface of the paper container for liquids, the first polyolefin resin layer is a low-density polyethylene resin layer derived from biomass, and the sealant layer is a second polyolefin resin layer located on the innermost surface of the paper container for liquids, the second polyolefin resin layer is a low-density polyethylene resin layer or a linear low-density polyethylene resin layer derived from fossil fuels, and the paper container for liquids has a rectangular cylindrical body, a rectangular plate-shaped bottom, and an upper part.

[0012] In the liquid paper container according to the present invention, the second polyolefin resin layer may be in contact with the paper base layer. Effect of the Invention

[0013] According to the present invention, it is possible to provide a packaging material that reduces the amount of fossil fuel used while suppressing the effect of odors specific to biomass components on the contents of a packaged product. [Brief description of the drawings]

[0014] [Figure 1] FIG. 1 is a cross-sectional view showing an example of a packaging material of the present invention. [Diagram 2]FIG. 1 is a diagram showing an example of a packaging container provided with the packaging material of the present invention. [Diagram 3] FIG. 1 is a diagram showing an example of a packaging container provided with the packaging material of the present invention. [Figure 4] FIG. 2 is a diagram showing the layer structure of the packaging materials of Examples 1 and 2. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] The laminate constituting the packaging material according to the present invention comprises a first polyolefin resin layer, a paper base layer and a sealant layer laminated in this order from the outer surface side to the innermost surface side. The innermost surface is the surface located on the side of the contents contained in the packaged product formed from the packaging material. The outer surface is the surface located opposite the innermost surface, and the laminate may comprise an additional layer on the outside of the layer located on the outer surface. In this application, the term "in this order" in descriptions such as "included in this order" and "laminated in this order" refers to the order in the direction from the outer surface side to the innermost surface side, unless otherwise specified.

[0016] In the present invention, the biomass ratio, which will be described below, of the entire laminate constituting the packaging material is preferably 40% or more, and more preferably 60% or more and less than 98%. 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.

[0017] 1 is a cross-sectional view showing an example of a packaging material 10 of the present invention. The packaging material 10 includes, in this order, a first polyolefin resin layer 11, a paper base layer 12, and a sealant layer 13, and the sealant layer 13 is a second polyolefin resin layer 14. The first polyolefin resin layer 11 constitutes an outer surface 10y of the packaging material 10, and the second polyolefin resin layer 14 constitutes an innermost surface 10x of the packaging material 10.

[0018] Each layer constituting the packaging material of the present invention will now be described.

[0019] (Paper base layer) The paper base layer functions as a base layer and is required to have a strength sufficient to withstand the process of laminating the polyolefin resin layer by extrusion molding. The paper base layer is preferably 100 g / m 2 More than 700g / m 2 Less than 150 g / m 2 More than 600g / m 2 More preferably, 200 g / m 2 More than 500g / m 2 The paper base layer may be any white paperboard, but from the standpoint of safety, it is preferable to use ivory paper, milk carton base paper, cup base paper, etc., which use natural pulp.

[0020] The paperboard used in the present invention may contain neutral rosin, alkyl ketene dimer, or alkenyl succinic anhydride as a sizing agent, and cationic polyacrylamide, cationic starch, or the like as a fixing agent. It is also possible to use aluminum sulfate to make the paper in a neutral range of pH 6 to 9. In addition to the above sizing agents, the paperboard may contain various papermaking fillers, retention aids, dry strength agents, wet strength agents, binders, dispersants, flocculants, plasticizers, and adhesives as appropriate, in addition to fixing agents.

[0021] (First polyolefin resin layer) The first polyolefin resin layer is a biomass-derived low-density polyethylene resin layer. The first polyolefin resin layer may function as a core layer of the packaging material. By having the core layer, the packaging material can exhibit excellent flexibility without breaking.

[0022] Here, the low density polyethylene (LDPE) constituting the low density polyethylene resin layer and the linear low density polyethylene (LLDEP) constituting the linear low density polyethylene resin layer described below will be explained. 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, typically a Ziegler-Natta catalyst, or a single-site catalyst, typically 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.

[0023] 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.

[0024] 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.

[0025] 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.

[0026] 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.

[0027] 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.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] The biomass-derived low-density polyethylene constituting the first polyolefin resin layer contains biomass-derived ethylene in an amount of preferably 5% by mass or more, more preferably 5% by mass to 95% by mass, even more preferably 25% by mass to 75% by mass, and most preferably 40% by mass to 75% by mass, based on the entire first polyolefin resin layer. If the concentration of biomass-derived ethylene in the first polyolefin resin layer 11 is 5% by mass or more, the amount of fossil fuel used can be reduced compared to conventional methods, and a carbon-neutral packaging material can be realized.

[0032] The first polyolefin resin layer has a melt flow rate (MFR) of 1 to 30 g / 10 min, preferably 3 to 25 g / 10 min, more preferably 4 to 20 g / 10 min. The melt flow rate is a value measured by method A 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 of the first polyolefin resin layer is 1 g / 10 min or more, the extrusion load during molding can be reduced. In addition, if the MFR of the first polyolefin resin layer is 30 g / 10 min or less, the mechanical strength of the first polyolefin resin layer can be increased.

[0033] The thickness of the first polyolefin resin layer is preferably from 10 to 100 μm, more preferably from 10 to 50 μm, and further preferably from 10 to 30 μm.

[0034] <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.

[0035] 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.

[0036] 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.

[0037] 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.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] 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.

[0042] 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.

[0043] 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.

[0044] 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.

[0045] <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.

[0046] 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.

[0047] 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.

[0048] 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%.

[0049] In the present invention, the biomass polyethylene or the biomass-derived resin layer does not need to be 100% biomass. If even a part of the packaging material is made of biomass-derived raw materials, this is in line with the purpose of the present invention, which is to reduce the amount of fossil fuel used compared to conventional methods.

[0050] (Sealant layer) The sealant layer is a second polyolefin resin layer located on the innermost surface of the packaging material. The second polyolefin resin layer is a low-density polyethylene resin layer derived from fossil fuels or a linear low-density polyethylene resin layer derived from fossil fuels. By making the second polyolefin resin layer located on the innermost surface of the packaging material a layer derived from fossil fuels, the effect of odor specific to biomass components on the contents can be suppressed. By making the second polyolefin resin layer low-density polyethylene or linear low-density polyethylene, the sealability can be improved and the layers can be firmly bonded together during sealing. The second polyolefin resin layer may be in contact with a paper base layer.

[0051] The second polyolefin resin layer has a melt flow rate (MFR) of 1 to 30 g / 10 min, preferably 3 to 25 g / 10 min, more preferably 4 to 20 g / 10 min. The melt flow rate is the value as described above. If the MFR of the sealant layer is 1 g / 10 min or more, the extrusion load during molding can be reduced. If the MFR of the sealant layer is 30 g / 10 min or less, the mechanical strength of the second polyolefin resin layer can be increased.

[0052] The thickness of the second polyolefin resin layer is preferably from 10 to 70 μm, more preferably from 20 to 50 μm, and further preferably from 20 to 40 μm.

[0053] (Printing layer) The packaging material in the present invention may further include a printed layer as necessary. The printed layer is a layer that forms any desired printed pattern such as letters, numbers, pictures, figures, symbols, patterns, etc. for decoration, display of contents, display of expiration date, display of manufacturer, seller, etc., and for other display and aesthetic purposes. The printed layer may be located, for example, on the outer surface side of the paper substrate layer. In addition, the printed layer may be provided on the entire surface or on a part of the surface. The printed layer may be formed using a conventionally known pigment or dye, and the method of forming the printed layer is not particularly limited.

[0054] (Manufacturing method of packaging materials) Next, an example of a method for producing the laminate constituting the packaging material of the present invention will be described.

[0055] An example of a manufacturing method of the packaging material 10 shown in Fig. 1 will be described. First, the above-mentioned paper base layer 12 is prepared. Then, a molten resin is extruded onto the paper base layer 12 by melt extrusion lamination to form the first polyolefin resin layer 11. Then, a molten resin constituting the second polyolefin resin layer 14 is extruded onto the paper base layer 12 by melt extrusion lamination to laminate the second polyolefin resin layer 14. This makes it possible to obtain the packaging material 10 including the first polyolefin resin layer 11, the paper base layer 12, and the second polyolefin resin layer 14 (sealant layer 13).

[0056] It is to be noted that after the second polyolefin resin layer 14 (sealant layer 13) is formed on the paper base layer 12, the first polyolefin resin layer 11 may be formed on the paper base layer 12.

[0057] (packaged products) Examples of packaged products formed using the packaging materials are described below.

[0058] <Paper cups> 2 is a perspective view with a portion of a paper cup 20 cut away. The paper cup 20 comprises a main body 21 having a body 22 and a flange 23, and a bottom 24. This is an example of a packaged product formed by using the above-mentioned packaging material 10 for the body material constituting the main body 21 and / or the base material constituting the bottom 24. Examples of contents that can be contained in the paper cup 20 include foods such as yogurt, ice cream, natto, milk drinks, fruit juice, and soft drinks such as tea.

[0059] <Liquid paper containers> 3 is a diagram showing a paper container for liquids 30, which is an example of a packaging product. Because the paper container for liquids has excellent barrier properties, it can be suitably used as a packaging product for all kinds of liquids, such as alcoholic beverages such as sake, shochu, and wine, dairy drinks such as milk, and soft drinks such as orange juice and tea, as well as car wax, and chemical products such as shampoo and detergent.

[0060] As shown in Fig. 3, the liquid paper container 30 has a rectangular cylindrical body 31 including sides, a rectangular plate-like bottom 32, and an upper portion 33, and is a so-called Gabeltop type container. The upper portion 33 has a pair of opposing inclined plates 34 and a pair of folded portions 35 located between the pair of inclined plates 34 and folded between the inclined plates 34. The pair of inclined plates 34 are bonded to each other by a glue tab 36 provided at each upper end. A spout may be attached to one of the pair of inclined plates 34, and the spout may be sealed with a cap. A flat-top type container may also be formed.

[0061] <Other aspects> Another aspect of the present invention is a packaging material comprising a first polyolefin resin layer, a paper base layer, and a sealant layer laminated in that order, wherein the first polyolefin resin layer is a biomass-derived low-density polyethylene resin layer, and the sealant layer is a second polyolefin resin layer located on the innermost surface of the packaging material, and the second polyolefin resin layer is a fossil fuel-derived low-density polyethylene resin layer or a linear low-density polyethylene resin layer. In the packaging material according to another aspect of the present invention, the second polyolefin resin layer may be in contact with the paper base layer. Another aspect of the present invention is a cup container using the above-mentioned packaging material for its body material, its base material, or both its body material and its base material. Another aspect of the present invention is a liquid packaging container using the above packaging material. EXAMPLES

[0062] 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.

[0063] [Example 1] Paper base layer: 270g / m 2 An acid-resistant light-shielding paper having a basis weight of 100 g was prepared. A printing layer was then formed on the paper base layer by gravure printing. A molten resin was then extruded onto the printing layer to form a first polyolefin resin layer. A biomass-derived low-density polyethylene was used as the first polyolefin resin layer. The thickness of the first polyolefin resin layer was 20 μm.

[0064] Next, the resin constituting the second polyolefin resin layer in a molten state was extruded onto the paper base layer to laminate the second polyolefin resin layer. Low-density polyethylene derived from fossil fuels was used as the second polyolefin resin layer. The thickness of the second polyolefin resin layer was 60 μm. This produced a packaging material.

[0065] The layer structure of the packaging material of this embodiment is expressed as follows. Bio LDPE20 / Printing / Acid-resistant light-shielding paper / Petrochemical LDPE60 The " / " indicates the boundary between layers. The leftmost layer is the layer that constitutes the outer surface of the packaging material, and the rightmost layer is the layer that constitutes the innermost surface of the packaging material. "Bio-LDPE" refers to the low-density polyethylene resin layer derived from biomass. "In" refers to the printing layer. "Acid-resistant light-blocking paper" refers to the paper base layer. "Petroleum-based LDPE" refers to the low-density polyethylene resin layer derived from fossil fuels. The numbers refer to the layer thickness (unit: μm).

[0066] Next, the packaging material of this example was used for the body and bottom materials to produce the main body 21 and bottom 24 of the paper cup 20 shown in Fig. 2. The paper cup 20 can contain, for example, yogurt.

[0067] Next, the packaging material of this example was used to produce a paper container 30 for liquids as shown in Fig. 3. The paper container 30 for liquids can contain, for example, milk or juice.

[0068] [Example 2] The paper base layer is made of acid-resistant cup base paper 350g / m 2 A packaging material was prepared in the same manner as in Example 1, except that the above was used.

[0069] The layer structure of the packaging material of this embodiment is expressed as follows. Bio LDPE 20 / Stamp / Acid-resistant cup base paper / Petrochemical LDPE 60 "Acid-resistant cup base paper" means the paper substrate layer.

[0070] Next, the packaging material of this example was used for the body and bottom materials to produce the main body 21 and bottom 24 of the paper cup 20 shown in Fig. 2. The paper cup 20 can contain, for example, yogurt.

[0071] Next, the packaging material of this example was used to produce a paper container 30 for liquids as shown in Fig. 3. The paper container 30 for liquids can contain, for example, milk or juice.

[0072] FIG. 4 shows examples of the layer configurations of the packaging materials of Examples 1 and 2. [Explanation of symbols]

[0073] 10 Packaging materials 11 First polyolefin resin layer 12 Paper base layer 13 Sealant layer 14 Second polyolefin resin layer 20 Paper Cups 21 Main body 22 Torso 23 Flange 24 Bottom 30 Liquid cartons 31 Torso 32 Bottom 33 Top 34 Inclined plate 35 Folding section 36 Glue

Claims

1. A cup container using a packaging material in which a first polyolefin resin layer, a paper base layer, and a sealant layer are laminated in this order as a body material and a bottom material, The first polyolefin resin layer is located on the outermost surface of the cup container, The first polyolefin resin layer is a biomass-derived low-density polyethylene resin layer, A cup container, wherein the sealant layer is a second polyolefin resin layer located on the innermost surface of the cup container, and the second polyolefin resin layer is a fossil fuel-derived low-density polyethylene resin layer or a linear low-density polyethylene resin layer.

2. The cup container according to claim 1 , wherein the second polyolefin resin layer is in contact with the paper base layer.

3. A liquid paper container using a packaging material in which a first polyolefin resin layer, a paper base layer, and a sealant layer are laminated in this order, The first polyolefin resin layer is located on the outermost surface of the liquid paper container, The first polyolefin resin layer is a biomass-derived low-density polyethylene resin layer, the sealant layer is a second polyolefin resin layer located on the innermost surface of the liquid paper container, the second polyolefin resin layer being a fossil fuel-derived low-density polyethylene resin layer or a linear low-density polyethylene resin layer, A paper container for liquids having a rectangular tubular body, a rectangular plate-shaped bottom, and an upper portion.

4. The paper container for liquid according to claim 3 , wherein the second polyolefin resin layer is in contact with the paper base layer.

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