JP2020158156A - Packaging material and packaging product - Google Patents

Abstract

To provide a packaging material which suppresses an influence of odor inherent to a biomass component to contents of a packaging product while reducing a used amount of fossil fuel.SOLUTION: In a packaging material, a first polyolefin resin layer, a paper base material layer and a sealant layer are layered in this order. The first polyolefin resin layer is a biomass-derived low density polyethylene resin layer. The sealant layer includes a second polyolefin resin layer positioned in the innermost surface of a packaging material. The second polyolefin resin layer is a fossil fuel-derived low density polyethylene resin layer or straight chain low density polyethylene resin layer.SELECTED DRAWING: Figure 1

Description

The present invention relates to a packaging material containing a biomass-derived component and a packaging product including the packaging material.

In recent years, with the growing demand for the construction of a recycling-oriented society, there is a desire to break away from fossil fuels in the material field as well as energy, and the use of biomass is drawing attention. Biomass is an organic compound photosynthesized from carbon dioxide and water, and by using it, it becomes carbon dioxide and water again, so-called carbon-neutral renewable energy. In recent years, the practical use of biomass plastics made from these biomass raw materials is rapidly progressing, and attempts are being made to produce various resins from the biomass raw materials.

As a biomass-derived resin, polylactic acid (PLA), which is produced via lactic acid fermentation, has started commercial production in advance, but its biodegradable performance and other general-purpose plastics are currently available. Because it is very different from the above, there are limits to the product applications and product manufacturing methods, and it has not been widely used. In addition, life cycle assessment (LCA) evaluation is being conducted for PLA, and discussions are being held on energy consumption during PLA manufacturing and equivalence when replacing general-purpose plastics.

Here, as the general-purpose plastic, various types such as polyethylene, polypropylene, polyvinyl chloride, polystyrene, and polyester are used. In particular, polyethylene is molded into films, sheets, bottles and the like, and is used for various purposes such as packaging materials, and is widely used all over the world. Therefore, the use of conventional fossil fuel-derived polyethylene has a large environmental load. Therefore, it is desired to reduce the amount of fossil fuel used by using a raw material derived from biomass in the production of polyethylene. For example, to date, research has been conducted on producing ethylene and butylene, which are raw materials for polyolefin resins, from renewable natural raw materials (see Patent Document 1).

Patent Document 2 proposes a paper cup as a product using a raw material derived from biomass. This is characterized in that the inner surface of the body member blank and the bottom member blank forming the body member and the bottom member of the paper cup is an inner thermoplastic resin layer made of a plant-derived biomass polyethylene resin.

Japanese Patent Publication No. 2011-506628 Japanese Unexamined Patent Publication No. 2015-214365

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

Therefore, an object of the present invention is to provide a packaging material that uses a biomass-derived raw material to reduce the amount of fossil fuel used and suppress the influence of the odor peculiar to the biomass component on the contents of the packaging product. And.

The present invention is a packaging material in which a first polyolefin resin layer, a paper base material layer, and a sealant layer are laminated in this order. 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 packaging material, and the second polyolefin resin layer is a low-density polyethylene resin layer derived from fossil fuel or a linear low-density polyethylene resin layer.

In the packaging material according to the present invention, the second polyolefin resin layer may be in contact with the paper base material layer.

The present invention is a cup container in which the above-mentioned packaging material is used as a body material, a bottom material, or a body material and a bottom material.

The present invention is a liquid packaging container using the above packaging material.

According to the present invention, it is possible to provide a packaging material that suppresses the influence of an odor peculiar to a biomass component on the contents of a packaging product while reducing the amount of fossil fuel used.

It is sectional drawing which shows an example of the packaging material of this invention. It is a figure which shows an example of the packaging container provided with the packaging material of this invention. It is a figure which shows an example of the packaging container provided with the packaging material of this invention. It is a figure which shows the layer structure of the packaging material of Examples 1 and 2.

The laminate constituting the packaging material according to the present invention includes a first polyolefin resin layer, a paper base material layer, and a sealant layer that are laminated in order from the outer surface side to the innermost surface side. The innermost surface is a surface of a packaged product formed from a packaging material, which is located on the content side of the packaged product. Further, although the outer surface is a surface located on the opposite side of the innermost surface, the laminated body may be provided with a further layer outside the layer located on the outer surface. In the present application, the term "order" in the description such as "preparing in this order" or "stacked in order" indicates an order in the direction from the outer surface side to the innermost surface side unless otherwise specified.

In the present invention, the biomass degree described below is preferably 40% or more, and more preferably 60% or more and less than 98% in the entire laminate constituting the packaging material. If the biomass level is within the above range, the amount of fossil fuel used can be reduced and the environmental load can be reduced. Unless otherwise specified, "biomass degree" means the weight ratio of biomass-derived components.

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

Hereinafter, each layer constituting the packaging material of the present invention will be described.

(Paper substrate layer)
The paper base material layer functions as a base material layer, and needs to have strength to withstand the step of laminating the polyolefin resin layer by extrusion molding. The paper substrate layer preferably has a basis weight of 100 g / m ² or more and 700 g / m ² or less, more preferably 150 g / m ² or more and 600 g / m ² or less, and further preferably 200 g / m ² or more and 500 g / m ² or less. To have. As the paper base material layer, white paperboard in general is targeted, but from the viewpoint of safety, it is particularly preferable to use ivory paper, milk carton base paper, cup base paper, etc. using natural pulp.

Further, in the paperboard used in the present invention, neutral rosin, alkyl ketene dimer, alkenyl succinic anhydride may be used as the sizing agent, and cationic polyacrylamide, cationic starch or the like is used as the fixing agent. May be good. It is also possible to use a sulfate band to make paper in a neutral region of pH 6 or more and pH 9 or less. In addition to the above sizing agents, if necessary, in addition to fixing agents, various paper-making fillers, yield improvers, dry paper strength enhancers, wet paper strength enhancers, binders, dispersants, flocculants, and plasticizers. An agent and an adhesive may be appropriately contained.

(First polyolefin resin layer)
The first polyolefin resin layer is a low-density polyethylene resin layer derived from biomass. The first polyolefin resin layer may function as a core layer of the packaging material. Since the packaging material has a core layer, it does not break and can exhibit excellent flexibility.

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 later will be described. The low-density polyethylene is a high-pressure ethylene homopolymer, and can be obtained by a conventionally known high-pressure radical polymerization method. The linear low-density polyethylene is a copolymer of ethylene and α-olefin polymerized using a multisite catalyst represented by a Ziegler-Natta catalyst or a single-site catalyst represented by a metallocene catalyst. All of them have a density of less than 930 kg / m ³ . Examples of the α-olefin that serves as a comonomer of the 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. Examples thereof include 4-methylpentene and the like, and mixtures thereof. Here, the density of polyethylene is a value measured according to the method specified in the method A of JIS K7112-1980 after performing the annealing described in JIS K6760-1980.

The above-mentioned single-site catalyst is a catalyst capable of forming a uniform active species, and is usually prepared by contacting a metallocene-based transition metal compound or a non-metallocene-based transition metal compound with an activation co-catalyst. A single-site catalyst is preferable because it has a uniform active site structure as compared with a multi-site catalyst, and thus can polymerize a polymer having a high molecular weight and a high uniformity structure. 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, which contains a ligand having a cyclopentadienyl skeleton, a cocatalyst, an organometallic compound if necessary, and each catalyst component of the carrier. is there.

In the transition metal compound of Group IV of the Periodic Table containing the ligand having the cyclopentadienyl skeleton, the cyclopentadienyl skeleton is a cyclopentadienyl group, a substituted cyclopentadienyl group or the like. .. The substituted cyclopentadienyl group includes 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, and a halosilyl. It has at least one substituent selected from the groups and the like. The substituted cyclopentadienyl group may have two or more substituents, and the substituents are bonded to each other to form a ring to form an indenyl ring, a fluorenyl ring, an azulenyl ring, a hydrogenated product thereof, or the like. It may be formed. Rings formed by bonding substituents to each other may further have substituents to each other.

In the transition metal compound of Group IV of the Periodic Table containing a ligand having a cyclopentadienyl skeleton, examples of the transition metal include zirconium, titanium and hafnium, and zirconium and hafnium are particularly preferable. The transition metal compound usually has two ligands having a cyclopentadienyl skeleton, and the ligands having each cyclopentadienyl skeleton are preferably bonded to each other by a cross-linking group. Examples of the cross-linking group include a substituted silylene group such as an alkylene group having 1 to 4 carbon atoms, a silylene group, a dialkyl silylene group and a diaryl silylene group, and a substituted gel millene group such as a dialkyl gel millene group and a diaryl gel millene group. It is preferably a substituted silylene group.

In the transition metal compound of Group IV of the periodic table, typical ligands other than the ligand having a cyclopentadienyl skeleton are hydrogen and 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 and the like.

The transition metal compound of Group IV of the Periodic Table, which contains a ligand having a cyclopentadienyl skeleton, may have one or a mixture of two or more as a catalyst component.

The co-catalyst is one in which the transition metal compound of Group IV of the Periodic Table can be effectively used as a polymerization catalyst, or the ionic charge in a catalytically activated state can be equalized. As co-catalysts, benzene-soluble organoxane of organoaluminum oxy compounds, benzene-insoluble organoaluminum oxy compounds, ion-exchange layered silicates, boron compounds, cations containing or not containing active hydrogen groups and non-coordinating anions Examples thereof include ionic compounds, lanthanoid salts such as lanthanum oxide, tin oxide, and phenoxy compounds containing a fluoro group.

The transition metal compound of Group IV of the Periodic Table, which contains a ligand having a cyclopentadienyl skeleton, may be used by supporting it on a carrier of an inorganic or organic compound. The carrier is preferably an inorganic or organic compound porous oxide, and specifically, ion-exchangeable layered silicate such as montmorillonite, SiO ₂ , Al ₂ O ₃ , MgO, ZrO ₂ , TiO ₂ , B ₂ O. ₃ , CaO, ZnO, BaO, ThO _2, etc. or a mixture thereof can be mentioned.

Further, examples of the organometallic compound used as necessary include organoaluminum compounds, organomagnesium compounds, and organozinc compounds. Of these, organoaluminum is preferably used.

The low-density polyethylene derived from biomass constituting the first polyolefin resin layer preferably contains ethylene derived from biomass in an amount of 5% by mass or more, more preferably 5% by mass or more and 95% by mass or less, based on the entire first polyolefin resin layer. It preferably contains 25% by mass or more and 75% by mass or less, and most preferably 40% by mass or more and 75% by mass or less. When 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 as compared with the conventional case, and a carbon-neutral packaging material can be realized.

The first polyolefin resin layer has a melt flow rate (MFR) of 1 to 30 g / 10 minutes, preferably 3 to 25 g / 10 minutes, and more preferably 4 to 20 g / 10 minutes. The melt flow rate is a value measured by the 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. When the MFR of the first polyolefin resin layer is 1 g / 10 minutes or more, the extrusion load during the molding process can be reduced. Further, when the MFR of the first polyolefin resin layer is 30 g / 10 minutes or less, the mechanical strength of the first polyolefin resin layer can be increased.

The thickness of the first polyolefin resin layer is preferably 10 to 100 μm, more preferably 10 to 50 μm, and even more preferably 10 to 30 μm.

<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 can be obtained by a conventionally known method. Hereinafter, an example of a method for producing ethylene-derived ethylene will be described.

Biomass-derived ethylene can be produced using biomass-derived ethanol as a raw material. In particular, it is preferable to use fermented ethanol derived from biomass obtained from plant raw materials. The plant material is not particularly limited, and conventionally known plants can be used. For example, corn, sugar cane, beets, and manioc can be mentioned.

Fermented ethanol derived from biomass refers to ethanol that has been purified after being produced by contacting a culture solution containing a carbon source obtained from a plant material with a microorganism that produces ethanol or a product derived from a crushed product thereof. Conventionally known methods such as distillation, membrane separation, and extraction can be applied to the purification of ethanol from the culture broth. For example, a method of adding benzene, cyclohexane or the like and azeotropically boiling the mixture, or removing water by membrane separation or the like can be mentioned.

In order to obtain the above ethylene, advanced purification such as reducing the total amount of impurities in ethanol to 1 ppm or less may be further performed at this stage.

A catalyst is usually used when ethylene is obtained by a dehydration reaction of ethanol, but the catalyst is not particularly limited, and a conventionally known catalyst can be used. Advantageous in the process is a fixed bed flow reaction in which the catalyst and the product can be easily separated, and for example, γ-alumina is preferable.

Since this dehydration reaction is an endothermic reaction, it is 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 a temperature of 100 ° C. or higher, more preferably 250 ° C. or higher, still more preferably 300 ° C. or higher is suitable. The upper limit is not particularly limited, but is preferably 500 ° C. or lower, more preferably 400 ° C. or lower, from the viewpoint of energy balance and equipment.

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. Generally, when a dehydration reaction is carried out, it is preferable that there is 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 was found that the amount of other olefins, especially butene, tends to increase in the absence of water. It is presumed that it is not possible to suppress ethylene dimerization after dehydration without the presence of a small amount of water. The lower limit of the allowable water content is 0.1% by mass or more, preferably 0.5% by mass or more. Although the upper limit is not particularly limited, it is preferably 50% by mass or less, more preferably 30% by mass or less, and further preferably 20% by mass or less from the viewpoint of mass balance and heat balance.

By performing the ethanol dehydration reaction in this way, a mixed portion of ethylene, water and a small amount of unreacted ethanol can be obtained. However, since ethylene is a gas at about 5 MPa or less at room temperature, it is separated from these mixed portions by gas-liquid separation. Ethylene can be obtained except for water and ethanol. This method may be performed by a known method.

Ethylene obtained by gas-liquid separation is further distilled, and the distillation method, operating temperature, residence time, etc. are not particularly limited except that the operating pressure at this time is normal pressure or higher.

When the raw material is ethanol derived from ammonia, the obtained ethylene contains carbonyl compounds such as ketones, aldehydes, and esters, which are impurities mixed in the ethanol fermentation process, carbon dioxide gas, which is a decomposition product thereof, and decomposition products of enzymes. It contains a very small amount of nitrogen-containing compounds such as amines and amino acids, which are impurities, and ammonia, which is a decomposition product thereof. Depending on the use of ethylene, these trace amounts of impurities may cause a problem and may be removed by purification. The purification method is not particularly limited, and can be performed by a conventionally known method. As a suitable purification operation, for example, an adsorption purification method can be mentioned. The adsorbent used is not particularly limited, and conventionally known adsorbents can be used. For example, a material having a high surface area is preferable, and the type of adsorbent is selected according to the type and amount of impurities in ethylene obtained by the dehydration reaction of ethanol derived from biomass.

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

<Biomass polyethylene>
Biomass polyethylene is obtained by polymerizing a monomer containing ethylene derived from biomass. As the biomass-derived ethylene, it is preferable to use the ethylene obtained by the above-mentioned production method. Since ethylene derived from biomass is used as the monomer as a raw material, the polyethylene polymerized 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. The raw material monomer for polyethylene does not have to contain 100% by mass of ethylene derived from biomass.

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

The biomass-derived ethylene concentration in the above polyethylene (hereinafter, may be referred to as “biomass degree”) is a value obtained by measuring the content of biomass-derived carbon by radiocarbon (C14) measurement. Since carbon dioxide in the atmosphere contains C14 at a fixed ratio (105.5 pMC), the C14 content in plants that grow by taking in carbon dioxide in the atmosphere, such as corn, is also about 105.5 pMC. It is known. It is also known that fossil fuels contain almost no C14. Therefore, by measuring the ratio of C14 contained in all carbon atoms in polyethylene, the ratio of biomass-derived carbon can be calculated and the weight ratio of biomass-derived components can be obtained.

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

In the present invention, the biomass polyethylene or the resin layer derived from biomass does not need to have a biomass degree of 100%. This is because if a raw material derived from biomass is used as a part of the packaging material, the purpose of the present invention is to reduce the amount of fossil fuel used as compared with the conventional case.

(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 fossil fuel-derived low-density polyethylene resin layer or a fossil fuel-derived linear low-density polyethylene resin layer. By forming the second polyolefin resin layer located on the innermost surface of the packaging material as a layer derived from fossil fuel, the influence of the odor peculiar to the biomass component on the contents can be suppressed. Further, by using low-density polyethylene or linear low-density polyethylene as the second polyolefin resin layer, the sealing property can be improved and the layers can be firmly adhered at the time of sealing. The second polyolefin resin layer may be in contact with the paper base material layer.

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

The thickness of the second polyolefin resin layer is preferably 10 to 70 μm, more preferably 20 to 50 μm, and even more preferably 20 to 40 μm.

(Print layer)
The packaging material in the present invention may further include a printing layer, if necessary. The printing layer is used for decoration, display of contents, display of expiration date, display of manufacturers, sellers, etc., and for display of other things and giving aesthetics, such as letters, numbers, patterns, figures, symbols, patterns, etc. A layer that forms any desired print pattern. The print layer may be located on the outer surface side of the paper base material layer, for example. Further, the print layer may be provided on the entire surface or may be provided on a part of the printed layer. The printed layer can be formed by using a conventionally known pigment or dye, and the forming method thereof is not particularly limited.

(Manufacturing method of packaging material)
Next, an example of a method for manufacturing a laminate constituting the packaging material of the present invention will be described.

An example of the manufacturing method of the packaging material 10 shown in FIG. 1 will be described. First, the above-mentioned paper base material layer 12 is prepared. Subsequently, the melted resin is extruded onto the paper base material layer 12 by the melt extrusion laminating method to form the first polyolefin resin layer 11. Subsequently, the resin constituting the second polyolefin resin layer 14 in the molten state is extruded onto the paper base material layer 12 by the melt extrusion laminating method, and the second polyolefin resin layer 14 is laminated. As a result, the packaging material 10 including the first polyolefin resin layer 11, the paper base material layer 12, and the second polyolefin resin layer 14 (sealant layer 13) can be obtained.

After forming the second polyolefin resin layer 14 (sealant layer 13) on the paper base material layer 12, the first polyolefin resin layer 11 may be formed on the paper base material layer 12.

(Packaging product)
An example of a packaging product formed by using a packaging material will be described.

<Paper cup>
FIG. 2 is a perspective view in which a part of the paper cup 20 is cut off. The paper cup 20 includes 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 portion 21 and / or the bottom material constituting the bottom portion 24. Examples of the contents contained in the paper cup 20 include foods such as yogurt, ice cream, natto, milk drinks, fruit juices, and soft drinks such as tea.

<Liquid paper container>
FIG. 3 is a diagram showing a liquid paper container 30 which is an example of a packaged product. Liquid paper containers have excellent barrier properties, so alcohols such as sake, shochu, and wine, milk beverages such as milk, foods such as soft drinks such as orange juice and tea, and chemical products such as car wax, shampoo, and detergents. It can be suitably used as a packaging product for all kinds of liquids.

As shown in FIG. 3, the liquid paper container 30 has a square tubular body portion 31 including a side surface, a square plate-shaped bottom portion 32, and an upper portion 33, and is a so-called Goebel top type container. There is. The upper portion 33 has a pair of inclined plates 34 facing each other and a pair of folding portions 35 located between the pair of inclined plates 34 and folded between the inclined plates 34. Further, the pair of inclined plates 34 are adhered to each other by a margin 36 provided at the upper end of each. A spout may be attached to one of the pair of slanted plates 34, and the spout may be sealed with a cap. Further, a flat top type container may be formed.

Next, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to the description of the following Examples as long as the gist of the present invention is not exceeded.

[Example 1]
As the paper substrate layer, an acid-resistant light-shielding paper having a weighing capacity of 270 g / m ² was prepared. Subsequently, a print layer was formed on the paper base material layer by gravure printing. Subsequently, the molten resin was extruded onto the printing layer to form a first polyolefin resin layer. As the first polyolefin resin layer, low-density polyethylene derived from biomass was used. The thickness of the first polyolefin resin layer was 20 μm.

Subsequently, the resin constituting the molten second polyolefin resin layer was extruded onto the paper base material layer, and the second polyolefin resin layer was laminated. As the second polyolefin resin layer, low-density polyethylene derived from fossil fuel was used. The thickness of the second polyolefin resin layer was 60 μm. As a result, a packaging material was produced.

The layer structure of the packaging material of this embodiment is expressed as follows.
Bio LDPE20 / Mark / Acid-resistant light-shielding paper / Petrified LDPE60
The "/" represents the boundary between layers. The leftmost layer is a layer constituting the outer surface of the packaging material, and the rightmost layer is a layer constituting the innermost surface of the packaging material.
"Bio LDPE" means a low density polyethylene resin layer derived from biomass. "Mark" means a print layer. "Acid-resistant light-shielding paper" means a paper substrate layer. "Petrified LDPE" means a low density polyethylene resin layer derived from fossil fuels. The numbers mean the thickness of the layer (unit: μm).

Subsequently, the packaging material of this example was used as the body material and the bottom material to prepare the main body 21 and the bottom 24 of the paper cup 20 shown in FIG. For example, yogurt can be stored in the paper cup 20.

Subsequently, using the packaging material of this example, the liquid paper container 30 shown in FIG. 3 was produced. For example, milk or juice can be stored in the liquid paper container 30.

[Example 2]
A packaging material was produced in the same manner as in Example 1 except that 350 g / m ² of acid-resistant cup base paper was used as the paper base material layer.

The layer structure of the packaging material of this embodiment is expressed as follows.
Bio LDPE20 / Mark / Acid-resistant cup base paper / Petrified LDPE60
"Acid resistant cup base paper" means a paper substrate layer.

Subsequently, the packaging material of this example was used as the body material and the bottom material to prepare the main body 21 and the bottom 24 of the paper cup 20 shown in FIG. For example, yogurt can be stored in the paper cup 20.

Subsequently, using the packaging material of this example, the liquid paper container 30 shown in FIG. 3 was produced. For example, milk or juice can be stored in the liquid paper container 30.

FIG. 4 summarizes examples of layer configurations of the packaging materials of Examples 1 and 2.

10 Packaging material 11 1st polyolefin resin layer 12 Paper base material layer 13 Sealant layer 14 2nd polyolefin resin layer 20 Paper cup 21 Main body 22 Body 23 Flange 24 Bottom 30 Liquid paper container 31 Body 32 Bottom 33 Top 34 Inclined plate 35 Folded part 36 Glue margin

Claims (4)

A packaging material in which a first polyolefin resin layer, a paper base material layer, and a sealant layer are laminated in this order.
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 packaging material, and the second polyolefin resin layer is a low-density polyethylene resin layer derived from fossil fuel or a linear low-density polyethylene resin layer. , Packaging material. The packaging material according to claim 1, wherein the second polyolefin resin layer is in contact with the paper base material layer. A cup container in which the packaging material according to claim 1 or 2 is used as a body material, a bottom material, or a body material and a bottom material. A container for liquid packaging using the packaging material according to claim 1 or 2.