JP2023165777A - Packaging material and packaging product - Google Patents

Abstract

To provide a packaging material which suppresses an influence of odor peculiar to biomass components on a content of a packaging product, while reducing the use amount of a fossil fuel.SOLUTION: In a packaging material, a first polyolefin resin layer, a paper base material layer, a first adhesive resin layer, a barrier layer, a second adhesive resin layer and a sealant layer are laminated sequentially. The first polyolefin resin layer is a low density polyethylene resin layer derived from a biomass. The sealant layer includes a second polyolefin resin layer positioned in the innermost surface of the packaging material. The second polyolefin resin layer is a low density polyethylene resin layer or a linear low-density polyethylene resin layer derived from a fossil fuel. The second adhesive resin layer comes into contact with the second polyolefin resin layer.SELECTED DRAWING: Figure 1

Description

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

In recent years, with increasing calls for building a recycling-oriented society, there is a desire to move away from fossil fuels in the materials field as well as energy, and the use of biomass is attracting 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, so it is a 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 also being made to produce various resins from biomass raw materials.

Commercial production of biomass-derived resins began first with polylactic acid (PLA), which is produced through lactic acid fermentation, but its performance as a plastic, including its biodegradability, is superior to that of today's general-purpose plastics. Because it is very different from the conventional method, there are limits to product applications and product manufacturing methods, and it has not become widely used. In addition, life cycle assessment (LCA) evaluations are being conducted on PLA, and discussions are taking place regarding the energy consumption during PLA production and the equivalency when replacing general-purpose plastics.

Here, various types of general-purpose plastics are used, such as polyethylene, polypropylene, polyvinyl chloride, polystyrene, and polyester. In particular, polyethylene is formed into films, sheets, bottles, etc., and is used for various purposes such as packaging materials, and is used in large quantities around the world. Therefore, using conventional polyethylene derived from fossil fuels has a large environmental impact. Therefore, it is desired to reduce the amount of fossil fuel used by using biomass-derived raw materials 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 raw materials derived from biomass. This is characterized in that the inner surfaces of the body member blank and the 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.

Special Publication No. 2011-506628 Japanese Patent Application Publication No. 2015-214365

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

Therefore, an object of the present invention is to provide a packaging material that uses biomass-derived raw materials to reduce the amount of fossil fuel used while suppressing the influence of the odor peculiar to biomass components on the contents of packaged products. shall be.

The present invention provides a packaging material in which a first polyolefin resin layer, a paper base material layer, a first adhesive resin layer, a barrier layer, a second adhesive resin layer, and a sealant layer are laminated in this order, wherein the first polyolefin resin layer is , a biomass-derived low-density polyethylene resin layer, the sealant layer comprising a second polyolefin resin layer located on the innermost surface of the packaging material, and the second polyolefin resin layer comprising a fossil fuel-derived low-density polyethylene resin. or a linear low density polyethylene resin layer, and the second adhesive resin layer is a packaging material in contact with the second polyolefin resin layer.

In the packaging material according to the invention, the barrier layer may include biomass-derived polyester.

In the packaging material according to the present invention, the barrier layer may further include a vapor-deposited film of an inorganic substance or an inorganic oxide, or a metal foil.

In the packaging material according to the present invention, the second adhesive resin layer is in contact with the barrier layer and may contain a carboxylic acid group-containing compound.

The present invention is a cup container using the above-mentioned packaging material for 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 odor peculiar to biomass components on the contents of packaged products while reducing the amount of fossil fuel used.

FIG. 1 is a sectional view showing an example of the packaging material of the present invention. FIG. 1 is a sectional view showing an example of the packaging material of the present invention. It is a figure showing an example of a packaging container provided with the packaging material of the present invention. It is a figure showing an example of a packaging container provided with the packaging material of the present invention. FIG. 2 is a diagram showing the layer structure of packaging materials of Examples 1 to 16.

The laminate constituting the packaging material according to the present invention includes a first polyolefin resin layer, a paper base layer, a first adhesive resin layer, a barrier layer, a second adhesive resin layer, and a sealant, which are laminated in order from the outer surface to the innermost surface. It has layers. The innermost surface is a surface located on the side of the contents accommodated in the packaging product in a packaging product formed from a packaging material. Moreover, although the outer surface is the surface located on the opposite side of the innermost surface, the laminate may include an additional layer outside the layer located on the outer surface. In the present application, the term "order" in descriptions such as "provided in this order" and "layered in this order" indicates the order in the direction from the outer surface side to the innermost surface side, unless otherwise specified.

In the present invention, the degree of biomass 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 degree is within the above range, the amount of fossil fuel used can be reduced and the environmental load can be reduced. Note that, unless otherwise specified, "biomass degree" indicates the weight ratio of biomass-derived components.

FIG. 1 is a 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 layer 12, a first adhesive resin layer 13, a barrier layer 14, a second adhesive resin layer 15, and a sealant layer 16 in this order, The sealant layer 16 includes a second polyolefin resin layer 17 . The first polyolefin resin layer 11 constitutes the outer surface 10y of the packaging material 10, and the second polyolefin resin layer 17 constitutes the innermost surface 10x of the packaging material 10.

FIG. 2 is a sectional view showing another example of the packaging material 10 of the present invention. The packaging material 10 includes a first polyolefin resin layer 11, a paper base layer 12, a first adhesive resin layer 13, a barrier layer 14, a second adhesive resin layer 15, and a sealant layer 16 in this order. Layer 16 includes a third polyolefin resin layer 18 and a second polyolefin resin layer 17. The first polyolefin resin layer 11 constitutes the outer surface 10y of the packaging material 10, and the second polyolefin resin layer 17 constitutes the innermost surface 10x of the packaging material 10.

Note that it is also possible to appropriately combine the plurality of layer configurations of the packaging material 10 shown in FIGS. 1 and 2 described above.

Each layer constituting the packaging material of the present invention will be explained below.

(Paper base 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 base 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 even more preferably 200 g/m ² or more and 500 g/m ^{2 or} less. It is something that you have. The paper base layer may be white paperboard in general, but from the viewpoint of safety, it is particularly preferable to use ivory paper using natural pulp, milk carton base paper, cup base paper, etc.

In addition, the paperboard used in the present invention may use neutral rosin, alkyl ketene dimer, alkenyl succinic anhydride as a sizing agent, and cationic polyacrylamide, cationic starch, etc. as a fixing agent. Good too. It is also possible to make paper in a neutral range of pH 6 or higher and pH 9 or lower using sulfuric acid band. In addition to the above-mentioned sizing agents, fixing agents, various fillers for paper manufacturing, retention aids, dry paper strength enhancers, wet paper strength enhancers, binders, dispersants, flocculants, plasticizers, etc., as necessary. It may contain an agent or an adhesive as appropriate.

(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 a core layer, the packaging material does not break and can exhibit excellent flexibility.

Here, low-density polyethylene (LDPE) constituting the low-density polyethylene resin layer and linear low-density polyethylene (LLDEP) constituting the linear low-density polyethylene resin layer described later will be explained. Low-density polyethylene is a high-pressure ethylene homopolymer and can be obtained by a conventionally known high-pressure radical polymerization method. Linear low-density polyethylene is a copolymer of ethylene and α-olefin that is polymerized using a multi-site catalyst such as a Ziegler-Natta catalyst or a single-site catalyst such as a metallocene catalyst. Both refer to those with a density of less than 0.930 g/cm ³ . The α-olefin that serves as a comonomer for linear low-density polyethylene includes α-olefins having 3 to 20 carbon atoms, such as propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-nonene, Examples include 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 performing annealing described in JIS K6760-1995.

The above-mentioned single-site catalyst is a catalyst capable of forming uniform active species, and is usually prepared by bringing a metallocene-based transition metal compound or a non-metallocene-based transition metal compound into contact with an activation cocatalyst. Single-site catalysts are preferable compared to multi-site catalysts because they have a more 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 preferable to use a metallocene catalyst. The metallocene catalyst is a catalyst containing a transition metal compound of Group IV of the periodic table containing a ligand having a cyclopentadienyl skeleton, a cocatalyst, an organometallic compound if necessary, and each catalyst component of a support. be.

In the above 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. . Examples of the substituted cyclopentadienyl group include 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 group. It has at least one substituent selected from groups. The substituted cyclopentadienyl group may have two or more substituents, and the substituents may combine with each other to form a ring, such as an indenyl ring, a fluorenyl ring, an azulenyl ring, or a hydrogenated product thereof. may be formed. The ring formed by bonding the substituents to each other may further have a substituent.

In a 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, hafnium, etc., and zirconium and hafnium are particularly preferred. The transition metal compound usually has two cyclopentadienyl skeleton-containing ligands, and each of the cyclopentadienyl skeleton-containing ligands is preferably bonded to each other via a crosslinking group. Examples of the crosslinking group include alkylene groups having 1 to 4 carbon atoms, substituted silylene groups such as silylene groups, dialkylsilylene groups, and diarylsilylene groups, and substituted germylene groups such as dialkylgermylene groups and diarylgermylene groups. Preferably, it is a substituted silylene group.

In transition metal compounds of Group IV of the periodic table, typical ligands other than those having a cyclopentadienyl skeleton include hydrogen, a hydrocarbon group having 1 to 20 carbon atoms (alkyl group), , alkenyl group, aryl group, alkylaryl group, aralkyl group, polyenyl group, etc.), halogen, metaalkyl group, metaaryl group, etc.

One or a mixture of two or more of the transition metal compounds of Group IV of the periodic table containing a ligand having a cyclopentadienyl skeleton can be used as a catalyst component.

The co-catalyst is one that can make the transition metal compound of Group IV of the periodic table effective as a polymerization catalyst, or can balance the ionic charges in a catalytically activated state. As a co-catalyst, organoaluminumoxy compounds such as benzene-soluble aluminoxane, benzene-insoluble organoaluminumoxy compounds, ion-exchanged layered silicates, boron compounds, cations containing or not containing active hydrogen groups, and non-coordinating anions can be used. Examples include ionic compounds, lanthanoid salts such as lanthanum oxide, tin oxide, and phenoxy compounds containing fluoro groups.

The transition metal compound of Group IV of the periodic table containing a ligand having a cyclopentadienyl skeleton may be used by being supported on an inorganic or organic compound carrier. The carrier is preferably a porous oxide of an inorganic or organic compound, and specifically, ion exchange layered silicates such as montmorillonite, SiO ₂ , Al ₂ O ₃ , MgO, ZrO ₂ , TiO ₂ , B ₂ O. ₃ , CaO, ZnO, BaO, _ThO2 , etc., or a mixture thereof.

Furthermore, examples of organometallic compounds that may be used as necessary include organoaluminum compounds, organomagnesium compounds, organozinc compounds, and the like. Among these, organic aluminum is preferably used.

The biomass-derived low density polyethylene constituting the first polyolefin resin layer preferably contains biomass-derived ethylene in an amount of preferably 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, most preferably 40% by mass or more and 75% by mass or less. 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 packaging materials, 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, more preferably 4 to 20 g/10 minutes. The melt flow rate is a value measured by method A under 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 minutes or more, the extrusion load during molding can be reduced. Moreover, if 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.

<Ethylene derived from biomass>
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 conventionally known methods. An example of a method for producing ethylene derived from biomass will be described below.

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 materials. The plant raw material is not particularly limited, and conventionally known plants can be used. Mention may be made, for example, of corn, sugar cane, beets, and manioc.

Fermented ethanol derived from biomass refers to ethanol produced by contacting a culture solution containing a carbon source obtained from a plant material with a product derived from an ethanol-producing microorganism or its crushed product, and then purified. Conventionally known methods such as distillation, membrane separation, and extraction can be applied to purify ethanol from the culture solution. For example, methods include adding benzene, cyclohexane, etc. and azeotropically distilling the mixture, or removing water by membrane separation or the like.

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

A catalyst is usually used to obtain ethylene through the dehydration reaction of ethanol, but this catalyst is not particularly limited, and conventionally known catalysts can be used. A fixed bed flow reaction is advantageous in terms of process because it allows easy separation of the catalyst and the product, and for example, γ-alumina is preferred.

Since this dehydration reaction is an endothermic reaction, it is usually carried out under heating conditions. The heating temperature is not limited as long as the reaction proceeds at a commercially useful reaction rate, but a temperature of preferably 100°C or higher, more preferably 250°C or higher, and still more preferably 300°C or higher is suitable. The upper limit is also not particularly limited, but from the viewpoint of energy balance and equipment, it is preferably 500°C or less, more preferably 400°C or less.

In the dehydration reaction of ethanol, the yield of the reaction is influenced by 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 water removal efficiency. However, it has been found that in the case of ethanol dehydration using a solid catalyst, the amount of other olefins, especially butene, tends to increase in the absence of water. This is probably because ethylene dimerization after dehydration cannot be suppressed unless a small amount of water is 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, still more preferably 20% by mass or less.

By performing the dehydration reaction of ethanol in this way, a mixed part of ethylene, water and a small amount of unreacted ethanol is obtained, but since ethylene is a gas at room temperature and below about 5 MPa, gas-liquid separation is performed from this mixed part. Ethylene can be obtained by excluding water and ethanol. This method may be performed by a known method.

The ethylene obtained by gas-liquid separation is further distilled, and there are no particular restrictions on the distillation method, operating temperature, residence time, etc., except that the operating pressure at this time is equal to or higher than normal pressure.

When the raw material is biomass-derived ethanol, the obtained ethylene contains 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 the decomposition product thereof, and enzyme decomposition products. Contains extremely small amounts of impurities such as nitrogen-containing compounds such as amines and amino acids, and their decomposition products such as ammonia. Depending on the use of ethylene, these minute amounts of impurities may pose a problem, so they 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 with a high surface area is preferable, and the type of adsorbent is selected depending on the type and amount of impurities in ethylene obtained by the dehydration reaction of biomass-derived ethanol.

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

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

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

The concentration of biomass-derived ethylene in the polyethylene (hereinafter sometimes 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 certain rate (105.5 pMC), the C14 content in plants that grow by taking in atmospheric carbon dioxide, such as corn, is also around 105.5 pMC. It is known. It is also known that fossil fuels contain almost no C14. Therefore, by measuring the proportion of C14 contained in all carbon atoms in polyethylene, the proportion of biomass-derived carbon can be calculated, and the weight proportion of biomass-derived components can be determined.

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

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

(Sealant layer)
The sealant layer includes 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.
Moreover, the sealant layer may further include a third polyolefin resin layer. The third polyolefin resin layer is a biomass-derived low density polyethylene resin layer.
Furthermore, the sealant layer may be a layer formed by coextruding a second polyolefin resin layer and a third polyolefin resin layer.

When the sealant layer includes a third polyolefin resin layer, the biomass degree of the sealant layer is preferably 10% or more and 90% or less, more preferably 20% or more and 80% or less, and 30% or more and 70% or less. It is more preferable that By setting the biomass degree within the above range, the amount of fossil fuel used can be further reduced, and the environmental load can be further reduced.

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

The thickness of the sealant layer is preferably 10 to 100 μm, more preferably 10 to 80 μm, and even more preferably 10 to 60 μm.

(Second polyolefin resin layer)
The second polyolefin resin layer is located on the innermost surface of the packaging material, and is a fossil fuel-derived low-density polyethylene resin layer or a fossil fuel-derived linear low-density polyethylene resin layer. By making the second polyolefin resin layer located on the innermost surface of the packaging material a layer derived from fossil fuel, it is possible to suppress the influence of the odor peculiar to the biomass component on the contents. Moreover, by making the second polyolefin resin layer of low-density polyethylene or linear low-density polyethylene, sealing performance can be improved, and the layers can be firmly bonded during sealing.

The thickness of the second polyolefin resin layer is preferably 10 to 100 μm, more preferably 10 to 80 μm, and even more preferably 10 to 60 μm.

(Third polyolefin resin layer)
The third polyolefin resin layer is a biomass-derived low density polyethylene resin layer. As the biomass-derived low density polyethylene resin layer in the third polyolefin resin layer, the same layer as the first polyolefin resin layer can be used. By providing the sealant layer with the third polyolefin resin layer, the biomass content of the packaging material can be further improved while making the innermost surface a layer derived from fossil fuel. Moreover, by adjusting the thickness of each layer included in the sealant layer, the biomass degree of the packaging material can be easily improved. Furthermore, the third polyolefin resin layer may be in contact with the second polyolefin resin layer.

The thickness of the third polyolefin resin layer is preferably 10 to 90 μm, more preferably 10 to 70 μm, and even more preferably 10 to 50 μm.

(barrier layer)
The barrier layer is a layer that provides or improves gas barrier properties that block the transmission of oxygen gas, water vapor, etc., and light shielding properties that block the transmission of visible light, ultraviolet rays, and the like. The barrier layer preferably contains biomass-derived polyester (hereinafter also referred to as biomass polyester). As a result, the amount of fossil fuel used can be reduced compared to the conventional method, and a carbon-neutral packaging material can be realized, as well as the fragrance retention of the packaging material can be further improved. The barrier layer may be formed from a resin composition containing biomass polyester. The barrier layer may also be a plastic film containing biomass polyester.

Biomass polyester is a polyester whose diol units are biomass-derived ethylene glycol and whose dicarboxylic acid units are fossil fuel-derived dicarboxylic acids. The resin composition forming the barrier layer contains, for example, 5% by mass or more and 45% by mass or less of biomass polyester based on the entire resin composition.

Biomass-derived ethylene glycol is made from biomass-derived ethanol, which is explained in biomass-derived ethylene. For example, biomass-derived ethylene glycol can be obtained by a method of generating ethylene glycol from biomass-derived ethanol via ethylene oxide using a conventionally known method. Moreover, commercially available biomass-derived ethylene glycol may be used, and for example, biomass-derived ethylene glycol commercially available from India Glycol Corporation can be suitably used.

Dicarboxylic acid derived from fossil fuels is used as the dicarboxylic acid unit of the polyester. As the dicarboxylic acid, aromatic dicarboxylic acids, aliphatic dicarboxylic acids, and derivatives thereof can be used. Examples of aromatic dicarboxylic acids include terephthalic acid and isophthalic acid, and examples of derivatives of aromatic dicarboxylic acids include lower alkyl esters of aromatic dicarboxylic acids, specifically methyl esters, ethyl esters, propyl esters, and butyl esters. Examples include esters. Among these, terephthalic acid is preferred, and as the aromatic dicarboxylic acid derivative, dimethyl terephthalate is preferred.

The biomass degree of the resin composition forming the barrier layer can be calculated by the same method as for biomass polyethylene described above. That is, by measuring the proportion of radioactive carbon (C14) contained in all carbon atoms in polyester, the proportion of biomass-derived carbon can be calculated, and the weight proportion of biomass-derived components can be determined.
Taking polyethylene terephthalate as an example, polyethylene terephthalate is a polymerization of ethylene glycol containing 2 carbon atoms and terephthalic acid containing 8 carbon atoms in a molar ratio of 1:1, so only biomass-derived ethylene glycol can be used. When using polyester, the weight ratio of the biomass-derived component in the polyester is 31.25%. Therefore, the theoretical value of biomass degree is 31.25%. Specifically, the mass (molecular weight) of polyethylene terephthalate is 192, of which the mass (molecular weight) derived from biomass-derived ethylene glycol is 60, so "60÷192×100=31.25". Further, the weight ratio of biomass-derived components in fossil fuel-derived polyethylene terephthalate is 0%, and the biomass degree of fossil fuel-derived polyethylene terephthalate is 0%. In the present invention, the biomass degree of the barrier layer is preferably 5.0% or more, more preferably 10.0% or more. Moreover, it is preferable that the biomass degree of the barrier layer is 30.0% or less.

The barrier layer can be formed by forming a film using the above resin composition, for example, by a T-die method. Specifically, after drying the resin composition described above, it is supplied to a melt extruder heated to a temperature (Tm) above the melting point of the resin composition to Tm + 70°C to melt the resin composition. For example, the barrier layer can be formed by extruding the material into a sheet from a die such as a T-die, and rapidly cooling and solidifying the extruded sheet material using a rotating cooling drum or the like. As the melt extruder, a single screw extruder, a twin screw extruder, a vent extruder, a tandem extruder, etc. can be used depending on the purpose.

The thickness of the barrier layer is preferably 5 μm or more, more preferably 8 μm or more, and even more preferably 12 μm or more. Thereby, the gas barrier properties and the strength of the barrier layer can be improved. Further, the thickness of the barrier layer is preferably 50 μm or less, more preferably 30 μm or less, even more preferably 25 μm or less, and particularly preferably 20 μm or less. Thereby, the moldability of the barrier layer can be improved.

The barrier layer included in the packaging material of the present invention may further include a vapor-deposited film of an inorganic substance or an inorganic oxide, or a metal foil. By providing the barrier layer with a vapor-deposited film of an inorganic substance or inorganic oxide, or a metal foil, gas barrier properties that block the transmission of oxygen gas and water vapor, and light shielding properties that block the transmission of visible light and ultraviolet rays are further improved. can do.

A vapor-deposited film of an inorganic substance and/or an inorganic oxide is vapor-deposited on at least one of the inner and outer surfaces of the plastic film. The deposited film can be formed by a conventionally known method using a conventionally known inorganic substance or inorganic oxide, and its composition and formation method are not particularly limited.

Examples of the deposited film include silicon (Si), aluminum (Al), magnesium (Mg), calcium (Ca), potassium (K), tin (Sn), sodium (Na), boron (B), and titanium (Ti). ), lead (Pb), zirconium (Zr), yttrium (Y), or other inorganic substances or evaporated films of inorganic oxides can be used. Particularly suitable for packaging products and the like, it is preferable to use a vapor-deposited film of aluminum metal, a vapor-deposited film of silicon oxide, aluminum metal, or aluminum oxide.

Inorganic oxides are expressed as, for example, MO _x such as SiO _x , _AlO expressed. The value range of X is 0 to 2 for silicon (Si), 0 to 1.5 for aluminum (Al), 0 to 1 for magnesium (Mg), 0 to 1 for calcium (Ca), Potassium (K) is 0 to 0.5, tin (Sn) is 0 to 2, sodium (Na) is 0 to 0.5, boron (B) is 0 to 1, 5, titanium (Ti) can take a value in the range of 0 to 2, lead (Pb) can take a value in the range of 0 to 1, zirconium (Zr) can take a value in the range of 0 to 2, and yttrium (Y) can take a value in the range of 0 to 1.5. In the above, when X=0, it is a completely inorganic substance (pure substance) and is not transparent, and the upper limit of the range of X is a completely oxidized value. Silicon (Si) and aluminum (Al) are preferably used for packaging products, with silicon (Si) having a value in the range of 1.0 to 2.0, and aluminum (Al) having a value in the range of 0.5 to 1.5. Values can be used.

The thickness of the vapor-deposited film of the inorganic substance or inorganic oxide as described above varies depending on the type of inorganic substance or inorganic oxide used, but is, for example, within the range of about 50 to 2000 Å, preferably about 100 to 1000 Å. It is preferable to select and form it arbitrarily. More specifically, in the case of a vapor deposited film of aluminum, the film thickness is preferably about 50 to 600 Å, more preferably about 100 to 450 Å, and in the case of a vapor deposited film of aluminum oxide or silicon oxide, The film thickness is preferably about 50 to 500 Å, more preferably about 100 to 300 Å.

Examples of methods for forming the deposited film include physical vapor deposition methods (PVD methods) such as vacuum evaporation methods, sputtering methods, and ion plating methods, or plasma chemical vapor deposition methods and thermochemical methods. Examples include a chemical vapor deposition method (CVD method) such as a vapor deposition method and a photochemical vapor deposition method.

When the barrier layer includes a vapor deposited film, the barrier layer may further include a gas barrier coating film on the vapor deposited film. Thereby, the deposited film can be mechanically and chemically protected, and the barrier properties of the barrier layer can be further improved. The gas barrier coating film is a cured film formed by a coating agent for gas barrier coating film consisting of a resin composition containing a metal alkoxide, a hydroxyl group-containing water-soluble resin, and a silane coupling agent added as necessary. . Further, the barrier layer may further include a vapor deposited film on the gas barrier coating film. That is, the barrier layer may include two or more vapor deposited films. In this case, the deposited film is preferably two or more types of deposited films from the viewpoint of gas barrier properties.

The mass ratio of hydroxyl group-containing water-soluble resin/metal alkoxide in the resin composition is preferably 5/95 or more and 20/80 or less, more preferably 8/92 or more and 15/85 or less. If it is smaller than this range, the barrier effect of the barrier coating film tends to be insufficient, and if it is larger than this range, the rigidity and brittleness of the barrier coating film tend to increase.

The thickness of the gas barrier coating film is preferably 100 to 800 nm. If it is thinner than this range, the barrier effect of the gas barrier coating film tends to be insufficient, and if it is thicker than this range, rigidity and brittleness tend to increase.

The metal alkoxide has the general formula R ₁ nM(OR ₂ )m (wherein R ₁ and R ₂ represent a hydrogen atom or an organic group having 1 to 8 carbon atoms, M represents a metal atom, and n represents an integer of 0 or more, m represents an integer of 1 or more, and n+m represents the valence of M. Even if each of the plurality of R ₁ and R ₂ in one molecule is the same, may be different.)...Represented by (I).

Specific examples of the metal atom represented by M in the metal alkoxide include silicon, zirconium, titanium, aluminum, tin, lead, and others. For example, an alkoxysilane in which M is Si (silicon) It is preferable to use

In the above general formula (I), specific examples of OR ₂ include a hydroxyl group, a methoxy group, an ethoxy group, an n-propoxy group, an n-butoxy group, an i-propoxy group, a butoxy group, and a 3-methacryloxy group. Examples include alkoxy groups such as 3-acryloxy groups and phenoxy groups, and phenoxy groups.

In the above, specific examples of R ₁ include methyl group, ethyl group, n-propyl group, isopropyl group, phenyl group, p-styryl group, 3-chloropropyl group, trifluoromethyl group, vinyl group, γ-glycyl group, Examples include sidoxypropyl group, methacryl group, and γ-aminopropyl group.

Specific examples of alkoxysilane include tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetraisopropoxysilane, tetrabutoxysilane, tetraphenoxysilane, methyltrimethoxysilane, methyltriethoxysilane, methyltripropoxysilane, Methyltributoxysilane, methyltriphenoxysilane, phenylphenoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, isopropyltrimethoxy Silane, isopropyltriethoxysilane, dimethyldiethoxysilane, diphenyldimethoxysilane, diphenyldiethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, p-styryltrimethoxysilane, 3- Methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, 3-acryloxypropyltrimethoxysilane Examples include various alkoxysilanes such as ethoxysilane, 3-chloropropyltriethoxysilane, trifluoromethyltrimethoxysilane, and 1,6-bis(trimethoxysilyl)hexane, and phenoxysilane. In this embodiment, condensation products of these alkoxysilanes can also be used, and specifically, for example, polytetramethoxysilane, polytetraethoxysilane, etc. can be used.

The silane coupling agent is used to adjust the crosslinking density of the cured film made of the metal alkoxide and the hydroxyl group-containing water-soluble resin to form a film with barrier properties and hot water treatment resistance.

The silane coupling agent has the general formula: R ₃ nSi(OR ₄ )4-n...(II)
(However, in the formula, R ₃ and R ₄ each independently represent an organic functional group, and n is 1 to 3.)
It is expressed as

In the above general formula (II), R ₃ is, for example, a hydrocarbon group such as an alkyl group or an alkylene group, an epoxy group, a (meth)acryloxy group, a ureido group, a vinyl group, an amino group, an isocyanurate group, or an isocyanate group. Examples include functional groups having the following. Specifically, at least one of two or three R ₃ 's is preferably a functional group having an epoxy group, such as a 3-glycidoxypropyl group and a 2-(3,4 epoxycyclohexyl) group. It is more preferable that Note that R ₃ may be the same or different.

In the above general formula (II), R ₄ is, for example, an organic functional group having 1 to 8 carbon atoms, preferably an alkyl group having 1 to 8 carbon atoms, which may have a branch, or an alkyl group having 3 to 8 carbon atoms. 7 is an alkoxyalkyl group. For example, examples of the alkyl group having 1 to 8 carbon atoms include methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, sec-butyl group, and the like. Examples of alkoxyalkyl groups having 3 to 7 carbon atoms include methyl ethyl ether, diethyl ether, methyl propyl ether, methyl isopropyl ether, ethyl propyl ether, ethyl isopropyl ether, methyl butyl ether, ethyl butyl ether, methyl sec-butyl ether, ethyl sec -butyl ether, methyl tert-butyl ether, ethyl tert-butyl ether, and other linear or branched ethers with one hydrogen atom removed. Note that (OR ₄ ) may be the same or different.

Examples of the silane coupling agent represented by the above general formula (II) include 3-glycidoxypropyltrimethoxysilane and 3-glycidoxypropyltriethoxysilane when n=1. When n=2, examples include 3-glycidoxypropylmethyldimethoxysilane and 3-glycidoxypropylmethyldiethoxysilane, and when n=3, examples include 3-glycidoxypropyldimethylmethoxysilane, 3-glycidoxypropyldimethylmethoxysilane, etc. Examples include sidoxypropyldimethylethoxysilane, 2-(3,4-epoxycyclohexyl)dimethylmethoxysilane, and 2-(3,4-epoxycyclohexyl)dimethylethoxysilane.

In particular, the crosslinking density of the cured barrier coating film using 3-glycidoxypropylmethyldimethoxysilane and 3-glycidoxypropylmethyldiethoxysilane is lower than that of the system using trialkoxysilane. Become. Therefore, while it is a film with excellent gas barrier properties and hot water treatment resistance, it becomes a flexible cured film and has excellent bending resistance, so packaging materials using this barrier film have gas barrier properties even after the Gelboflex test. Hard to deteriorate.

The silane coupling agent can be used as a mixture of those with n=1, 2, or 3, and the quantitative ratio and the amount of the silane coupling agent used are determined by the design of the cured film of the barrier coating film. .

The hydroxyl group-containing water-soluble resin is capable of dehydration co-condensation with a metal alkoxide, and the degree of saponification is preferably 90% or more and 100% or less, more preferably 95% or more and 100% or less, and 99% or more and 100% or less. More preferred. If the degree of saponification is smaller than the above range. The hardness of the barrier coating film tends to decrease.

Specific examples of hydroxyl group-containing water-soluble resins include polyvinyl alcohol resins, ethylene-vinyl alcohol copolymers, polymers of bifunctional phenol compounds and bifunctional epoxy compounds, etc. They may be used, or two or more types may be used in combination, or they may be copolymerized. Among these, polyvinyl alcohol is particularly preferred because of its excellent flexibility and affinity, and polyvinyl alcohol-based resins are preferred.

Specifically, for example, polyvinyl alcohol resin obtained by saponifying polyvinyl acetate or ethylene/vinyl alcohol copolymer obtained by saponifying a copolymer of ethylene and vinyl acetate is used. can do.
Examples of such polyvinyl alcohol resins include PVA-124 (saponification degree = 99%, polymerization degree = 2,400) manufactured by Kuraray Co., Ltd., and Gohsenol NM-14 (Saponification degree = 2,400) manufactured by Nippon Gosei Chemical Industry Co., Ltd. degree of polymerization = 99%, degree of polymerization = 1,400).

Metal foil is a member obtained by rolling metal. The metal foil is located on at least one of the inner and outer sides of the plastic film. As the metal foil, a conventionally known metal foil can be used. The metal foil is preferably aluminum foil or the like from the viewpoints of workability, cost, etc.

The thickness of the metal foil is preferably 3 to 20 μm, more preferably 5 to 15 μm.

If the barrier layer comprises a metal foil, an adhesive may be used between the plastic film and the metal foil. The plastic film and the metal foil can be bonded with an adhesive by a conventionally known method, for example, a dry lamination method. In the dry lamination method, an adhesive is applied to the surface of the plastic film or metal foil that is to be laminated between the plastic film and the metal foil and dried, and then the plastic film is bonded through the dried adhesive. and laminated with metal foil. Adhesives to be applied include, for example, one-component or two-component hardening or non-curing vinyl-based, (meth)acrylic-based, polyamide-based, polyester-based, polyether-based, polyurethane-based, epoxy-based, rubber. Solvent-based, water-based, or emulsion-based adhesives can be used. As the two-component curing adhesive, a cured product of a polyol and an isocyanate compound can be used. Coating methods for the above laminating adhesive include, for example, a direct gravure roll coating method, a gravure roll coating method, a kiss coating method, a reverse roll coating method, a Fontaine method, a transfer roll coating method, and other methods. .

The adhesive may include a biomass-derived component. For example, when the adhesive contains a cured product of a polyol and an isocyanate compound, at least either the polyol or the isocyanate compound may contain a biomass-derived component. Thereby, the biomass degree of the packaging material can be further improved.

(First adhesive resin layer)
The first adhesive resin layer is a layer located between the paper base layer and the barrier layer. The first adhesive resin layer may be a layer in contact with the paper base layer. Further, the first adhesive resin layer may be a layer in contact with the barrier layer.

The first adhesive resin layer contains a thermoplastic resin. The first adhesive resin layer can be formed by a conventionally known method, such as a melt extrusion lamination method or a sand lamination method. Thermoplastic resins that can be used in the first adhesive resin layer include polyolefin resins such as polyethylene resins and polypropylene resins, cyclic polyolefin resins, copolymer resins containing these resins as main components, modified resins, or Mixtures (including alloys) 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), and metallocene catalysts. Polymerized ethylene-α-olefin copolymer, ethylene-polypropylene random or block copolymer, ethylene-vinyl acetate copolymer (EVA), ethylene-acrylic acid copolymer (EAA), ethylene-ethyl acrylate copolymer polymer (EEA), ethylene-methacrylic acid copolymer (EMAA), ethylene-methyl methacrylate copolymer (EMMA), ethylene-maleic acid copolymer, ionomer resin, and to improve the adhesion between layers. For example, an acid-modified polyolefin resin obtained by modifying the polyolefin resin described above with an unsaturated carboxylic acid such as acrylic acid, methacrylic acid, maleic acid, maleic anhydride, fumaric acid, or itaconic acid can be used. Further, a resin obtained by graft polymerizing or copolymerizing an unsaturated carboxylic acid, an unsaturated carboxylic acid anhydride, or an ester monomer to the polyolefin resin can be used. These materials can be used alone or in combination of two or more. As the cyclic polyolefin resin, for example, cyclic polyolefins such as ethylene-propylene copolymer, polymethylpentene, polybutene, and polynorbornene can be used. These resins can be used alone or in combination.

In addition, as the above-mentioned polyethylene resin, one using biomass-derived ethylene explained in the first polyolefin resin layer as a monomer unit may be used. Thereby, the biomass content of the packaging material can be further improved.

The adhesive resin constituting the first adhesive resin layer contains one or more compounds selected from the group consisting of epoxy group-containing compounds, silane group-containing compounds, carboxylic acid group-containing compounds, and acid anhydride-containing compounds. For example, a polyethylene resin or a polypropylene resin can be used. Among these, it is preferable that the first adhesive resin layer contains a carboxylic acid group-containing compound. Thereby, it is possible to reduce the thermal stress that the barrier layer receives in the step of bonding the paper base layer and the barrier layer via the first adhesive resin layer by the sand lamination method. Moreover, when the first adhesive resin layer comes into contact with the vapor deposited film, it is possible to suppress the gas barrier properties from deteriorating.

When polyethylene resin is used as the adhesive resin constituting the first adhesive resin layer, the density is preferably in the range of 920 to 970 kg/m ³ , and preferably in the range of 920 to 965 kg/m ³ because it has excellent heat resistance. More preferred. By setting the density of the adhesive resin constituting the first adhesive resin layer within these ranges, it is possible to effectively suppress the generation of pinholes and the peeling and wrinkles of the vapor deposited film when heat is applied to the packaging material. can. Furthermore, it is also possible to suppress the generation of thermal pinholes caused by heat during the production of packaged products.

The polyethylene resin constituting the adhesive resin of the first adhesive resin layer is an ethylene homopolymer, an ethylene/α-olefin copolymer, or a composition thereof, and the molecular chain form thereof may be linear or linear. It may also have a long chain branch having 6 or more carbon atoms.

In the first adhesive resin layer, examples of the ethylene homopolymer include medium/low pressure ethylene homopolymers, high pressure polyethylene homopolymers, and the like. The medium/low pressure ethylene homopolymer can be obtained by a conventionally known medium/low pressure ionic polymerization method. Further, the high-pressure polyethylene homopolymer can be obtained by a conventionally known high-pressure radical polymerization method.

In the first adhesive resin layer, the α-olefin used in the ethylene/α-olefin copolymer includes propylene, 1-butene, 4-methyl-1-pentene, 3-methyl-1-butene, 1-pentene, 1 -hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene, etc., and one or more of these may be used. The method for obtaining the ethylene/α-olefin copolymer is not particularly limited, and examples include high, medium, and low pressure ionic polymerization methods using Ziegler-Natta catalysts, Phillips catalysts, and single-site catalysts. can. Such copolymers can be conveniently selected from commercially available products.

Examples of the epoxy group-containing compound contained in the adhesive resin constituting the first adhesive resin layer include epoxidized vegetable oil (epoxidation of unsaturated double bonds in natural vegetable oil), glycidyl ether type, glycidyl amine type, and glycidyl ester type. etc. Among these, epoxidized vegetable oil is more preferred from the viewpoint of safety when used in food packaging materials. For example, epoxidized soybean oil, epoxidized linseed oil, epoxidized olive oil, epoxidized safflower oil, epoxidized corn oil, etc. are used. The content of such an epoxy group-containing compound is, for example, 0.01 to 10 parts by weight, and 0.01 to 5.0 parts by weight, based on 100 parts by weight of the adhesive resin constituting the first adhesive resin layer. preferable.

A silane oligomer is suitably used as the silane group-containing compound contained in the adhesive resin constituting the first adhesive resin layer. More specifically, in order to improve adhesiveness, a silane oligomer containing any one of an epoxy group, a mercapto group, and an alkoxy group, or several of these groups in the molecule is desirable. The silane oligomer is blended in an amount of 0.01 to 10 parts by weight, preferably 0.01 to 5 parts by weight, based on 100 parts by weight of the adhesive resin constituting the first adhesive resin layer.

As the carboxylic acid group-containing compound contained in the adhesive resin constituting the first adhesive resin layer, an ethylene-unsaturated carboxylic acid or a copolymer with an ester thereof can be used. More specific examples include ethylene-acrylic acid copolymer, ethylene-ethyl acrylate copolymer, ethylene-methacrylic acid copolymer, and ethylene-methyl methacrylate copolymer. It is also possible to use an ionomer resin in which molecules of ethylene-unsaturated carboxylic acid are cross-linked with metal ions.

The acid anhydride-containing compound contained in the adhesive resin constituting the first adhesive resin layer is preferably a maleic acid-modified polyolefin resin such as a maleic acid-modified polyethylene resin or a maleic acid-modified polypropylene resin. More preferred are maleic anhydride-modified polyolefin resins such as modified polyethylene resins and maleic anhydride-modified polypropylene resins. Note that the maleic acid-modified polyolefin resin is obtained by graft polymerizing maleic acid to a polyolefin resin.

The thickness of the first adhesive resin layer is preferably 10 to 50 μm, more preferably 10 to 30 μm, even more preferably 10 to 20 μm.

In addition to the above-mentioned various compounds, the resin constituting the first adhesive resin layer may optionally contain antioxidants, light stabilizers, antistatic agents, lubricants, antiblocking agents, etc. commonly used in polyolefin resins. Additives may be added as long as they do not impair the purpose of the present invention.

(Second adhesive resin layer)
The second adhesive resin layer is a layer located between the barrier layer and the sealant layer. The second adhesive resin layer may be a layer in contact with the barrier layer. Further, the second adhesive resin layer may be a layer in contact with the sealant layer. Furthermore, the second adhesive resin layer may be a layer formed by coextrusion molding with the sealant layer. The second adhesive resin layer can be the same as the first adhesive resin layer described above.

The thickness of the second adhesive resin layer is preferably 10 to 100 μm, more preferably 10 to 80 μm, and even more preferably 10 to 60 μm.

(Printing layer)
The packaging material in the present invention may further include a printed layer, if necessary. The printing layer contains letters, numbers, pictures, figures, symbols, patterns, etc. for decoration, display of contents, display of expiration date, display of manufacturer, seller, etc., and for giving a sense of beauty. This layer forms any desired printed pattern. For example, the printing layer may be located on the outer side of the paper base layer. Further, the printing layer may be provided on the entire surface or on a portion thereof. The printing layer can be formed using conventionally known pigments and dyes, and the forming method is not particularly limited.

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

An example of a method for manufacturing the packaging material 10 shown in FIG. 1 will be described. First, the paper base layer 12 described above is prepared. Subsequently, the molten resin is extruded onto the paper base layer 12 by a melt extrusion lamination method to form the first polyolefin resin layer 11. Subsequently, the paper base layer 12 and the barrier layer 14 are laminated with the first adhesive resin layer 13 interposed therebetween by a sand lamination method. Subsequently, the resin constituting the second adhesive resin layer 15 in a molten state and the resin constituting the second polyolefin resin layer 17 are co-extruded onto the barrier layer 14 by a melt extrusion lamination method to form the second adhesive resin layer 15. A second polyolefin resin layer 17 is laminated via. Thereby, a packaging material comprising the first polyolefin resin layer 11, the paper base layer 12, the first adhesive resin layer 13, the barrier layer 14, the second adhesive resin layer 15, and the second polyolefin resin layer 17 (sealant layer 16) You can get 10.

Note that after forming the first adhesive resin layer 13 , barrier layer 14 , second adhesive resin layer 15 , and second polyolefin resin layer 17 (sealant layer 16 ) on the paper base layer 12 , a second adhesive resin layer 13 is formed on the paper base layer 12 . 1 polyolefin resin layer 11 may be formed.

An example of a method for manufacturing the packaging material 10 shown in FIG. 2 will be described. First, the paper base layer 12 described above is prepared. Subsequently, the molten resin is extruded onto the paper base layer 12 by a melt extrusion lamination method to form the first polyolefin resin layer 11. Subsequently, the paper base material layer 12 and the barrier layer 14 are laminated with the first adhesive resin layer 13 interposed therebetween by a sand lamination method. Subsequently, a resin constituting the second adhesive resin layer 15 in a molten state, a resin constituting the third polyolefin resin layer 18, and a second polyolefin resin layer 17 are formed on the barrier layer 14 by a melt extrusion lamination method. The third polyolefin resin layer 18 and the second polyolefin resin layer 17 are laminated via the second adhesive resin layer 15. As a result, the first polyolefin resin layer 11, the paper base layer 12, the first adhesive resin layer 13, the barrier layer 14, the second adhesive resin layer 15, the third polyolefin resin layer 18, and the second polyolefin resin layer 17 (sealant A packaging material 10 can be obtained comprising a layer 16).

Note that after forming the first adhesive resin layer 13, barrier layer 14, second adhesive resin layer 15, and third polyolefin resin layer 18 and second polyolefin resin layer 17 (sealant layer 16) on the paper base layer 12, The first polyolefin resin layer 11 may be formed on the paper base layer 12.

(Packaged products)
An example of a packaged product formed by using the packaging material will be described.

<Paper cup>
FIG. 3 is a partially cutaway perspective view of the paper cup 20. The paper cup 20 includes a main body portion 21 having a body portion 22 and a flange portion 23, and a bottom portion 24. This is an example of a packaging product formed by using the above-mentioned packaging material 10 for the body material forming the main body portion 21 and/or the bottom material forming the bottom portion 24. Examples of the contents stored in the paper cup 20 include foods such as yogurt, ice cream, natto, milk drinks, fruit juice, and soft drinks such as tea.

<Liquid paper container>
FIG. 4 is a diagram showing a liquid paper container 30, which is an example of a packaged product. Paper containers for liquids have excellent barrier properties, so they can be used for alcoholic beverages 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 liquids in general.

As shown in FIG. 4, the liquid paper container 30 has a rectangular cylindrical body 31 including side surfaces, a rectangular plate-shaped bottom 32, and an upper part 33, and is a so-called Goebel top type container. There is. The upper part 33 has a pair of opposing inclined plates 34 and a pair of folding parts 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 an adhesive margin 36 provided at the upper end of each plate. Note that a spout may be attached to one of the pair of inclined plates 34, and the spout may be sealed with a cap. Alternatively, a flat-top container may be formed.

<Other aspects>
Another aspect of the present invention is a packaging material in which a first polyolefin resin layer, a paper base layer, a first adhesive resin layer, a barrier layer, a second adhesive resin layer, and a sealant layer are laminated in this order, wherein the first The polyolefin resin layer is a low-density polyethylene resin layer derived from biomass, the sealant layer includes 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. The packaging material is a low-density polyethylene resin layer or a linear low-density polyethylene resin layer.
In a packaging material according to another aspect of the invention, the barrier layer may include biomass-derived polyester.
In the packaging material according to another aspect of the present invention, the barrier layer may further include a vapor-deposited film of an inorganic substance or an inorganic oxide, or a metal foil.
In the packaging material according to another aspect of the present invention, the second adhesive resin layer is in contact with the barrier layer and may contain a carboxylic acid group-containing compound.
In the packaging material according to another aspect of the present invention, the sealant layer further includes a third polyolefin resin layer, and the third polyolefin resin layer may be a biomass-derived low-density polyethylene resin layer.
In the packaging material according to another aspect of the present invention, the third polyolefin resin layer may be in contact with the second polyolefin resin layer.
In the packaging material according to another aspect of the present invention, the second adhesive resin layer may be in contact with the sealant layer.
Another aspect of the present invention is a cup container using the above-mentioned packaging material for a body material, a bottom material, or a body material and a bottom material.
Another aspect of the present invention is a liquid packaging container using the above packaging material.

Next, the present invention will be explained in more detail with reference to examples, but the present invention is not limited to the description of the following examples unless it exceeds the gist thereof.

[Example 1]
Acid-resistant paper having a basis weight of 300 g/m ² was prepared as the paper base layer. Subsequently, a printed layer was formed on the paper base layer by gravure printing. Subsequently, the molten resin was extruded onto the printed layer to form a first polyolefin resin layer. As the first polyolefin resin layer, biomass-derived low density polyethylene was used. The thickness of the first polyolefin resin layer was 15 μm.

Subsequently, the paper base material layer and the barrier layer (thickness: 12 μm) were bonded together via the first adhesive resin layer by a sand lamination method. As the barrier layer, a biomass-derived polyethylene terephthalate film (hereinafter also referred to as bio-PET film) was used. As the first adhesive resin layer, low density polyethylene derived from fossil fuels was used. The thickness of the first adhesive resin layer was 15 μm.

Subsequently, the resin constituting the second adhesive resin layer in a molten state and the resin constituting the second polyolefin resin layer are coextruded onto the bio-PET film, and the second polyolefin resin layer is applied via the second adhesive resin layer. (Sealant layer) was laminated. As the second adhesive resin layer, an ethylene-methacrylic acid copolymer derived from fossil fuel was used. As the second polyolefin resin layer, low density polyethylene derived from fossil fuels was used. The thickness of the second adhesive resin layer was 15 μm. The thickness of the second polyolefin resin layer was 20 μm. This produced a packaging material.

The layer structure of the packaging material of this example is expressed as follows.
Bio LDPE15/Seal/Acid-proof paper/Gratted LDPE15/Bio PET12/Gratted EMAA15/Petrified LDPE20
"/" represents 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" means a biomass-derived low-density polyethylene resin layer. "Mark" means a printed layer. "Acid-resistant paper" means a paper base layer. “Glamented LDPE” refers to an adhesive resin layer made of low-density polyethylene derived from fossil fuels. "Bio-PET" means bio-PET film. “Metallic EMAA” means an adhesive resin layer made of fossil fuel-derived ethylene-methacrylic acid copolymer. "Petrochemical LDPE" means a layer of low-density polyethylene resin derived from fossil fuels. The numbers refer to the layer thickness (in μm).

Subsequently, the main body part 21 and bottom part 24 of the paper cup 20 shown in FIG. 3 were manufactured using the packaging material of this example for the body material and the bottom material. The paper cup 20 can contain, for example, yogurt.

Subsequently, a liquid paper container 30 shown in FIG. 4 was produced using the packaging material of this example. The liquid paper container 30 can contain, for example, milk or juice.

[Example 2]
A packaging material was produced in the same manner as in Example 1, except that a fossil fuel-derived ethylene-methacrylic acid copolymer was used as the first adhesive resin layer.

The layer structure of the packaging material of this example is expressed as follows.
Bio LDPE15/Mark/Acid-proof paper/Gratted EMAA15/Bio PET12/Gratted EMAA15/Petrified LDPE20

Subsequently, the main body part 21 and bottom part 24 of the paper cup 20 shown in FIG. 3 were manufactured using the packaging material of this example for the body material and the bottom material. The paper cup 20 can contain, for example, yogurt.

Subsequently, a liquid paper container 30 shown in FIG. 4 was produced using the packaging material of this example. The liquid paper container 30 can contain, for example, milk or juice.

[Example 3]
As a barrier layer, an inorganic oxide (silicon oxide) vapor-deposited film is formed on the bio-PET film, a gas barrier coating film is further formed on the inorganic oxide vapor-deposited film, and further, aluminum oxide (AlO _x ) is vapor-deposited on top of that. A packaging material was produced in the same manner as in Example 1, except that a film-formed layer (thickness: 12 μm) was used. Note that the aluminum oxide (AlO _x ) vapor-deposited film is in contact with the second adhesive resin layer.

Specifically, as a method for forming a gas barrier coating film, first, tetraethoxysilane as a metal alkoxide and glycan as a silane coupling agent are added to a solution in which water, isopropyl alcohol, and 0.5N hydrochloric acid are mixed and the pH is adjusted. Solution A was prepared by mixing sidoxypropyltrimethoxysilane while cooling.
A solution B was prepared by mixing polyvinyl alcohol, water, and isopropyl alcohol as a water-soluble polymer. A solution obtained by mixing liquid A and liquid B was used as a coating agent for a gas barrier coating film.
The coating agent for a gas barrier coating film prepared above was coated on the inorganic oxide (silicon oxide) vapor-deposited film of the bio-PET film by a spin coating method.
Thereafter, heat treatment was performed in an oven at 180°C for 60 seconds to form a gas barrier coating film with a thickness of approximately 400 nm on the inorganic oxide (silicon oxide) deposited film, and aluminum oxide (AlO _x ) was deposited on top of the gas barrier coating film. A layer film was formed.

The layer structure of the packaging material of this example is expressed as follows.
Bio LDPE15/Seal/Acid-proof paper/Gratted LDPE15/Bio IB-PET12/Gratted EMAA15/Petrified LDPE20
"Bio IB-PET" means a bio-PET film in which an inorganic oxide vapor-deposited film, a gas barrier coating film, and an aluminum oxide vapor-deposited film are laminated.

Subsequently, the main body part 21 and bottom part 24 of the paper cup 20 shown in FIG. 3 were manufactured using the packaging material of this example for the body material and the bottom material. The paper cup 20 can contain, for example, yogurt.

Subsequently, a liquid paper container 30 shown in FIG. 4 was produced using the packaging material of this example. The liquid paper container 30 can contain, for example, milk or juice.

[Example 4]
A packaging material was produced in the same manner as in Example 3, except that a fossil fuel-derived ethylene-methacrylic acid copolymer was used as the first adhesive resin layer.

The layer structure of the packaging material of this example is expressed as follows.
Bio LDPE15/Seal/Acid-proof paper/Gratted EMAA15/Bio IB-PET12/Gratted EMAA15/Petrified LDPE20

Subsequently, the main body part 21 and bottom part 24 of the paper cup 20 shown in FIG. 3 were manufactured using the packaging material of this example for the body material and the bottom material. The paper cup 20 can contain, for example, yogurt.

Subsequently, a liquid paper container 30 shown in FIG. 4 was produced using the packaging material of this example. The liquid paper container 30 can contain, for example, milk or juice.

[Example 5]
A packaging material was produced in the same manner as in Example 1, except that a layer (thickness: 12 μm) in which an aluminum vapor-deposited film was formed on a bio-PET film was used as the barrier layer. Note that the aluminum vapor deposited film is in contact with the first adhesive resin layer.

The layer structure of the packaging material of this example is expressed as follows.
Bio LDPE15/Seal/Acid-proof paper/Gratted LDPE15/Bio VM-PET12/Gratted EMAA15/Petrified LDPE20
"Bio VM-PET" means a bio-PET film on which an aluminum vapor-deposited film is laminated.

Subsequently, the main body part 21 and bottom part 24 of the paper cup 20 shown in FIG. 3 were manufactured using the packaging material of this example for the body material and the bottom material. The paper cup 20 can contain, for example, yogurt.

Subsequently, a liquid paper container 30 shown in FIG. 4 was produced using the packaging material of this example. The liquid paper container 30 can contain, for example, milk or juice.

[Example 6]
A packaging material was produced in the same manner as in Example 5, except that a fossil fuel-derived ethylene-methacrylic acid copolymer was used as the first adhesive resin layer.

The layer structure of the packaging material of this example is expressed as follows.
Bio LDPE15/Seal/Acid-proof paper/Gratted EMAA15/Bio VM-PET12/Gratted EMAA15/Petrified LDPE20

Subsequently, the main body part 21 and bottom part 24 of the paper cup 20 shown in FIG. 3 were manufactured using the packaging material of this example for the body material and the bottom material. The paper cup 20 can contain, for example, yogurt.

Subsequently, a liquid paper container 30 shown in FIG. 4 was produced using the packaging material of this example. The liquid paper container 30 can contain, for example, milk or juice.

[Example 7]
Same as in Example 1 except that a layer of bio-PET film (thickness: 12 μm) and aluminum foil (thickness: 7 μm) laminated via adhesive by dry lamination method was used as the barrier layer. A packaging material was prepared. In the dry lamination method, a polyester polyol, which is a reaction product of a fossil fuel-derived polyfunctional alcohol and a fossil fuel-derived polyfunctional carboxylic acid, was prepared as a main ingredient. In addition, a fossil fuel-derived isocyanate compound was prepared as a curing agent.

The layer structure of the packaging material of this example is expressed as follows.
Bio LDPE15/Stamp/Acid-proof paper/Gratted LDPE15/AL foil 7/Glued/Bio PET12/Gratted EMAA15/Petrified LDPE20
"AL foil" means aluminum foil. "Tsutaku" means adhesive.

Subsequently, the main body part 21 and bottom part 24 of the paper cup 20 shown in FIG. 3 were manufactured using the packaging material of this example for the body material and the bottom material. The paper cup 20 can contain, for example, yogurt.

Subsequently, a liquid paper container 30 shown in FIG. 4 was produced using the packaging material of this example. The liquid paper container 30 can contain, for example, milk or juice.

[Example 8]
A packaging material was produced in the same manner as in Example 7, except that a fossil fuel-derived ethylene-methacrylic acid copolymer was used as the first adhesive resin layer.

The layer structure of the packaging material of this example is expressed as follows.
Bio LDPE15/Seal/Acid-proof paper/Gratted EMAA15/AL foil 7/Glued/Bio PET12/Gratted EMAA15/Petrified LDPE20

Subsequently, the main body part 21 and bottom part 24 of the paper cup 20 shown in FIG. 3 were manufactured using the packaging material of this example for the body material and the bottom material. The paper cup 20 can contain, for example, yogurt.

Subsequently, a liquid paper container 30 shown in FIG. 4 was produced using the packaging material of this example. The liquid paper container 30 can contain, for example, milk or juice.

[Example 9]
The second adhesive resin layer and the sealant layer were formed in the same manner as in Example 1, except that the second adhesive resin layer, the third polyolefin resin layer, and the second polyolefin resin layer were formed by coextrusion. A packaging material was produced. As the second adhesive resin layer, an ethylene-methacrylic acid copolymer derived from fossil fuel was used. As the third polyolefin resin layer, biomass-derived low density polyethylene was used. As the second polyolefin resin layer, low density polyethylene derived from fossil fuels was used. The thickness of the second adhesive resin layer was 10 μm. The thickness of the third polyolefin resin layer was 10 μm. The thickness of the second polyolefin resin layer was 15 μm.

The layer structure of the packaging material of this example is expressed as follows.
Bio LDPE15/Seal/Acid-proof paper/Gratted LDPE15/Bio PET12/Gratted EMAA10/Bio LDPE10/Petrite LDPE15

Subsequently, the main body part 21 and bottom part 24 of the paper cup 20 shown in FIG. 3 were manufactured using the packaging material of this example for the body material and the bottom material. The paper cup 20 can contain, for example, yogurt.

Subsequently, a liquid paper container 30 shown in FIG. 4 was produced using the packaging material of this example. The liquid paper container 30 can contain, for example, milk or juice.

[Example 10]
A packaging material was produced in the same manner as in Example 9, except that a fossil fuel-derived ethylene-methacrylic acid copolymer was used as the first adhesive resin layer.

The layer structure of the packaging material of this example is expressed as follows.
Bio LDPE15/Seal/Acid-proof paper/Gratted EMAA15/Bio PET12/Gratted EMAA10/Bio LDPE10/Petrified LDPE15

Subsequently, the main body part 21 and bottom part 24 of the paper cup 20 shown in FIG. 3 were manufactured using the packaging material of this example for the body material and the bottom material. The paper cup 20 can contain, for example, yogurt.

Subsequently, a liquid paper container 30 shown in FIG. 4 was produced using the packaging material of this example. The liquid paper container 30 can contain, for example, milk or juice.

[Example 11]
The second adhesive resin layer and the sealant layer were formed in the same manner as in Example 3, except that the second adhesive resin layer, the third polyolefin resin layer, and the second polyolefin resin layer were formed by coextrusion. A packaging material was produced. As the second adhesive resin layer, an ethylene-methacrylic acid copolymer derived from fossil fuel was used. As the third polyolefin resin layer, biomass-derived low density polyethylene was used. As the second polyolefin resin layer, low density polyethylene derived from fossil fuels was used. The thickness of the second adhesive resin layer was 10 μm. The thickness of the third polyolefin resin layer was 10 μm. The thickness of the second polyolefin resin layer was 15 μm.

The layer structure of the packaging material of this example is expressed as follows.
Bio LDPE15/Seal/Acid-proof paper/Gratted LDPE15/Bio IB-PET12/Gratted EMAA10/Bio LDPE10/Petrified LDPE15

Subsequently, the main body part 21 and bottom part 24 of the paper cup 20 shown in FIG. 3 were manufactured using the packaging material of this example for the body material and the bottom material. The paper cup 20 can contain, for example, yogurt.

Subsequently, a liquid paper container 30 shown in FIG. 4 was produced using the packaging material of this example. The liquid paper container 30 can contain, for example, milk or juice.

[Example 12]
A packaging material was produced in the same manner as in Example 11, except that a fossil fuel-derived ethylene-methacrylic acid copolymer was used as the first adhesive resin layer.

The layer structure of the packaging material of this example is expressed as follows.
Bio LDPE15/Seal/Acid-proof paper/Gratted EMAA15/Bio IB-PET12/Gratted EMAA10/Bio LDPE10/Petrified LDPE15

Subsequently, the main body part 21 and bottom part 24 of the paper cup 20 shown in FIG. 3 were manufactured using the packaging material of this example for the body material and the bottom material. The paper cup 20 can contain, for example, yogurt.

Subsequently, a liquid paper container 30 shown in FIG. 4 was produced using the packaging material of this example. The liquid paper container 30 can contain, for example, milk or juice.

[Example 13]
The second adhesive resin layer and the sealant layer were formed in the same manner as in Example 5, except that the second adhesive resin layer, the third polyolefin resin layer, and the second polyolefin resin layer were formed by coextrusion. A packaging material was produced. As the second adhesive resin layer, an ethylene-methacrylic acid copolymer derived from fossil fuel was used. As the third polyolefin resin layer, biomass-derived low density polyethylene was used. As the second polyolefin resin layer, low density polyethylene derived from fossil fuels was used. The thickness of the second adhesive resin layer was 10 μm. The thickness of the third polyolefin resin layer was 10 μm. The thickness of the second polyolefin resin layer was 15 μm.

The layer structure of the packaging material of this example is expressed as follows.
Bio LDPE15/Seal/Acid-proof paper/Gratted LDPE15/Bio VM-PET12/Gratted EMAA10/Bio LDPE10/Petrified LDPE15

Subsequently, the main body part 21 and bottom part 24 of the paper cup 20 shown in FIG. 3 were manufactured using the packaging material of this example for the body material and the bottom material. The paper cup 20 can contain, for example, yogurt.

Subsequently, a liquid paper container 30 shown in FIG. 4 was produced using the packaging material of this example. The liquid paper container 30 can contain, for example, milk or juice.

[Example 14]
A packaging material was produced in the same manner as in Example 13, except that a fossil fuel-derived ethylene-methacrylic acid copolymer was used as the first adhesive resin layer.

The layer structure of the packaging material of this example is expressed as follows.
Bio LDPE15/Seal/Acid-proof paper/Gratted EMAA15/Bio VM-PET12/Gratted EMAA10/Bio LDPE10/Petrified LDPE15

Subsequently, the main body part 21 and bottom part 24 of the paper cup 20 shown in FIG. 3 were manufactured using the packaging material of this example for the body material and the bottom material. The paper cup 20 can contain, for example, yogurt.

Subsequently, a liquid paper container 30 shown in FIG. 4 was produced using the packaging material of this example. The liquid paper container 30 can contain, for example, milk or juice.

[Example 15]
The second adhesive resin layer and the sealant layer were formed in the same manner as in Example 7, except that the second adhesive resin layer, the third polyolefin resin layer, and the second polyolefin resin layer were formed by coextrusion. A packaging material was produced. As the second adhesive resin layer, an ethylene-methacrylic acid copolymer derived from fossil fuel was used. As the third polyolefin resin layer, biomass-derived low density polyethylene was used. As the second polyolefin resin layer, low density polyethylene derived from fossil fuels was used. The thickness of the second adhesive resin layer was 10 μm. The thickness of the third polyolefin resin layer was 10 μm. The thickness of the second polyolefin resin layer was 15 μm.

The layer structure of the packaging material of this example is expressed as follows.
Bio LDPE15/Seal/Acid-proof paper/Gratted LDPE15/AL foil 7/Glued/Bio PET12/Gratted EMAA10/Bio LDPE10/Petrite LDPE15

Subsequently, the main body part 21 and bottom part 24 of the paper cup 20 shown in FIG. 3 were manufactured using the packaging material of this example for the body material and the bottom material. The paper cup 20 can contain, for example, yogurt.

Subsequently, a liquid paper container 30 shown in FIG. 4 was produced using the packaging material of this example. The liquid paper container 30 can contain, for example, milk or juice.

[Example 16]
A packaging material was produced in the same manner as in Example 15, except that a fossil fuel-derived ethylene-methacrylic acid copolymer was used as the first adhesive resin layer.

The layer structure of the packaging material of this example is expressed as follows.
Bio LDPE15/Seal/Acid-proof paper/Gratted EMAA15/AL foil 7/Glued/Bio PET12/Gratted EMAA10/Bio LDPE10/Petrified LDPE15

Subsequently, the main body part 21 and bottom part 24 of the paper cup 20 shown in FIG. 3 were manufactured using the packaging material of this example for the body material and the bottom material. The paper cup 20 can contain, for example, yogurt.

Subsequently, a liquid paper container 30 shown in FIG. 4 was produced using the packaging material of this example. The liquid paper container 30 can contain, for example, milk or juice.

FIG. 5 shows examples of the layer configurations of the packaging materials of Examples 1 to 16.

10 Packaging material 11 First polyolefin resin layer 12 Paper base layer 13 First adhesive resin layer 14 Barrier layer 15 Second adhesive resin layer 16 Sealant layer 17 Second polyolefin resin layer 18 Third polyolefin resin layer 20 Paper cup 21 Main body 22 Body part 23 Flange part 24 Bottom part 30 Liquid paper container 31 Body part 32 Bottom part 33 Upper part 34 Inclined plate 35 Folding part 36 Gluing margin

Claims (6)

A packaging material in which a first polyolefin resin layer, a paper base layer, a first adhesive resin layer, a barrier layer, a second adhesive resin 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 includes 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. ,
A packaging material, wherein the second adhesive resin layer is in contact with the second polyolefin resin layer. The packaging material according to claim 1, wherein the barrier layer comprises biomass-derived polyester. The packaging material according to claim 2, wherein the barrier layer further comprises a vapor-deposited film of an inorganic substance or an inorganic oxide, or a metal foil. The packaging material according to any one of claims 1 to 3, wherein the second adhesive resin layer is in contact with the barrier layer and contains a carboxylic acid group-containing compound. A cup container using the packaging material according to any one of claims 1 to 4 for a body material, a bottom material, or a body material and a bottom material. A liquid packaging container using the packaging material according to any one of claims 1 to 4.