Packaging materials, packaging bags and packaging bodies

Abstract

To provide a packaging material that uses polyolefin as the main material and can achieve good suppression of fragrance component permeation. [Solution] A packaging material for packaging contents containing fragrance, comprising, in this order, a first polyolefin layer, an inorganic vapor deposition layer, a gas barrier coating layer, and a second polyolefin layer having heat-sealing properties.

Description

[Technical Field]

[0001] This disclosure relates to packaging materials, packaging bags, and packaging bodies. Specifically, this disclosure relates to packaging materials for packaging contents containing fragrances, which can suppress the dissipation and transfer of fragrances, and which are material recyclable. This disclosure also relates to packaging bags and packaging bodies using said material recyclable packaging materials. [Background technology]

[0002] In recent years, hair care products such as shampoos and conditioners, as well as liquid laundry detergents and fabric softeners, have been sold in flexible packaging to reduce plastic use, and it has become common practice for households to transfer these products into plastic bottles for use.

[0003] These packaging materials (flexible packaging materials) are made by laminating plastic films and forming bags. One example of the manufacturing method involves forming a printed layer on a 12 μm thick polyethylene terephthalate (PET) film using gravure printing. This printed surface is then bonded to a 15 μm thick nylon film (Ny) using a dry lamination method with a urethane-based adhesive to obtain a laminate. Furthermore, the nylon film surface of this laminate is similarly bonded to a 100 μm thick linear low-density polyethylene (LLDPE) to obtain a PET / Ny / LLDPE laminate. Next, the LLDPE surfaces of this laminate are heat-sealed facing each other to form a bag and obtain a packaging bag. In terms of shape, a standing pouch with a spout is common, considering its suitability for display in stores and ease of pouring.

[0004] Furthermore, laminates with PET / LLDPE or Ny / LLDPE configurations are also used in a similar manner, by forming a printed layer on a 15 μm thick nylon film (Ny) or a 12 μm thick polyethylene terephthalate (PET) film using gravure printing, and then bonding this printed surface to a 120 μm thick linear low-density polyethylene (LLDPE) using a dry lamination method with a urethane-based adhesive.

[0005] By the way, instead of such a flexible packaging material that combines different resin types, a flexible packaging material mainly made of polyolefin has been proposed (see, for example, Patent Document 1). This is because, from the perspective of waste problems such as marine pollution caused by plastics, the demand for flexible packaging materials that can be material recycled has been increasing in recent years for the purpose of reducing the usage amount of plastics.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] However, when a flexible packaging material mainly made of polyolefin such as polyethylene or polypropylene is filled with a content containing a fragrance and sealed, compared with the case of filling a packaging bag made of a laminate of PET / Ny / LLDPE structure or Ny / LLDPE structure, the dissipation of fragrance components and the transfer of fragrance to other articles accompanying it have become problems.

[0008] The present disclosure has been made in view of the above circumstances, and an object thereof is to provide a packaging material that can achieve good suppression of permeation of fragrance components by using polyolefin as a main material. The present disclosure also aims to provide a packaging bag and a package using the packaging material.

Means for Solving the Problems

[0009] The inventors have studied a polyolefin packaging material that is recyclable and in which the dissipation of fragrance components and the transfer of fragrance are unlikely to occur. As a result, they have found that at least a packaging material obtained by laminating a first polyolefin layer, an inorganic vapor deposition layer, a gas barrier coating layer, and a second polyolefin layer having heat sealability can achieve the above object, and thus have completed the packaging material of the present disclosure.

[0010] That is, the packaging material according to one aspect of the present disclosure is a packaging material for packaging a content containing a fragrance, and includes a first polyolefin layer, an inorganic vapor deposition layer, a gas barrier coating layer, and a second polyolefin layer having heat sealability in this order.

[0011] Since the glass transition point (Tg) of PET is around 70°C and the glass transition point of Ny is around 50°C, when these are used as the constituent films of the packaging bag, under normal use conditions, the molecules in the amorphous portions of PET and Ny are in a glassy state where thermal motion is gentle, and it is difficult for fragrance components to dissolve in these films, and permeation is suppressed. Therefore, when using a packaging bag composed of a laminate having a PET / Ny / LLDPE structure or a Ny / LLDPE structure, dissipation of fragrance components and transfer of fragrance to other articles are unlikely to occur. In contrast, since the glass transition temperature of polyethylene is around -125°C and the glass transition temperature of polypropylene is around 0°C, when these are used as the constituent films of the packaging bag, at normal use temperatures, in polyethylene and polypropylene, the thermal motion of the molecular chains in the amorphous portions is in an active state, and fragrance components easily dissolve in these films and permeate outside the packaging bag. In a flexible packaging material mainly made of polyolefin such as polyethylene and polypropylene, it is important to have a layer structure as in the present invention from the viewpoint of suppressing the permeation of fragrance components. This means that by devising the layer structure, it is possible to obtain fragrance permeation suppression properties comparable to those of a polyester packaging material even with a polyolefin packaging material.

[0012] In one embodiment, the gas barrier coating layer may be a heat-dried product of a composition containing at least one of a hydroxyl group-containing polymer compound and its hydrolysate, and at least one selected from the group consisting of metal alkoxides, silane coupling agents, and their hydrolysates.

[0013] In one embodiment, the gas barrier coating layer may contain a polycarboxylic acid polymer crosslinked with a polyvalent metal or a polyvalent metal compound.

[0014] In one embodiment, the gas barrier coating layer may be a cured product of an adhesive composition containing a resin having at least one aromatic ring and one aliphatic ring.

[0015] In one embodiment, the inorganic vapor-deposited layer may contain at least one of aluminum oxide and silicon oxide.

[0016] In one embodiment, the first polyolefin layer and the second polyolefin layer may be made of the same material.

[0017] In one embodiment, the first polyolefin layer and the second polyolefin layer may be made of polyethylene.

[0018] In one embodiment, the first polyolefin layer and the second polyolefin layer may be made of polypropylene.

[0019] A packaging bag relating to one aspect of this disclosure is formed from the above-mentioned packaging material.

[0020] A package relating to one aspect of this disclosure comprises the above-mentioned packaging bag and contents containing a fragrance packaged inside the packaging bag.

[0021] In one embodiment, the fragrance may contain at least one of esters and terpenes. [Effects of the Invention]

[0022] This disclosure provides a packaging material that uses polyolefin as the main material and can achieve good suppression of fragrance component permeation. Furthermore, this disclosure provides a packaging bag and a packaging body using this packaging material. [Brief explanation of the drawing]

[0023] [Figure 1] Figure 1 is a cross-sectional view showing one embodiment of the packaging material relating to this disclosure. [Modes for carrying out the invention]

[0024] Preferred embodiments of this disclosure will be described in detail below, with reference to the drawings as appropriate. In the drawings, the same or corresponding parts are denoted by the same reference numerals, and redundant descriptions are omitted. Furthermore, the dimensional ratios in the drawings are not limited to those shown.

[0025] <Packaging material> The packaging material of this disclosure is for packaging contents containing fragrances. Examples of such fragrances include esters such as isobutyl formate, ethyl acetate, methyl butyrate, ethyl butyrate, ethyl hexanoate, ethyl methylbutyrate, ethyl 2-methylbutyrate, ethyl 2-methylvalerate, hexyl acetate, allyl hexanoate, allyl heptanoate, benzyl acetate, amyl butyrate, amyl valerate, isoamyl acetate, α-methylbenzyl acetate, β-pinene, allyl cyclohexanepropionate, 2-phenoxyethyl isobutyrate, and methyl salicylate, as well as terpenes such as limonene, citronellol, linalool, nerol, nerolidol, α-terpineol, myrcene, thymol, and thioterpineol. Examples of contents containing these fragrances include hair care products such as shampoos and conditioners, liquid laundry detergents, and fabric softeners. The packaging material of this disclosure is particularly excellent at inhibiting the permeation of esters and terpenes. Both esters and terpenes share the common characteristic of having solubility parameters (SP values) that are similar to those of polyolefins.

[0026] The solubility parameter (SP value) is a value defined by the regular solution theory, and it is empirically known that the smaller the difference in the SP values of two components, the greater the solubility. The SP value of polyethylene is 8.6 (cal / cm 3 ) 1 / 2 , and the SP value of polypropylene is 8.0 (cal / cm 3 ) 1 / 2 . On the other hand, the SP values of esters are about 7.8 - 8.5 (cal / cm 3 ) 1 / 2 , and the SP values of terpenes such as limonene are about 7.3 - 7.8 (cal / cm 3 ) 1 / 2 , and the difference from the SP values of polyethylene and polypropylene is small. Incidentally, the SP value of PET is 13.3 (cal / cm 3 ) 1 / 2 , and the SP value of Ny is 9.9 - 13.7 (cal / cm 3 ) 1 / 2 . Compared with the SP values of polyolefins, the difference from the SP values of esters and terpenes is large, indicating that the solubility is small. As described above, from the perspective of the SP value, the suppression of flavor permeation in conventional packaging is also explained.

[0027] The packaging material of the present disclosure includes a first polyolefin layer, an inorganic vapor deposition layer, a gas barrier coating layer, and a second polyolefin layer having heat sealability in this order.

[0028] FIG. 1 is a cross-sectional view showing one aspect of the packaging material according to the present disclosure. The packaging material 10 includes a first polyolefin layer 1, an inorganic vapor deposition layer 2, a gas barrier coating layer 3, and a second polyolefin layer 4 having heat sealability in this order. In the figure, the inorganic vapor deposition layer 2 is formed on one surface of the first polyolefin layer 1, but the inorganic vapor deposition layer may be formed on both surfaces of the first polyolefin layer 1. Further, the second polyolefin layer 4 may be laminated on the gas barrier coating layer 3 via an adhesive layer (not shown).

[0029] (First polyolefin layer) The first polyolefin layer serves as a substrate (polyolefin film) for forming the inorganic vapor deposition layer. Examples of polyolefins constituting the first polyolefin layer include polyethylene and polypropylene.

[0030] As for polyethylene, high-density polyethylene (HDPE) is a suitable choice considering its suitability for vapor deposition, printing, bag making, and filling. Furthermore, to improve physical properties such as flexibility, a multilayer film such as high-density polyethylene (HDPE) / medium-density polyethylene (MDPE) / low-density polyethylene (LDPE) / medium-density polyethylene (MDPE) / high-density polyethylene (HDPE), formed by co-extrusion, may be used as the first polyolefin layer.

[0031] Polypropylene can be broadly classified into stretched polypropylene, homopolymer, random copolymer, block copolymer, and terpolymer. The polymer type is selected according to the application and required performance. However, when used as a base film for packaging, homopolymer polypropylene is preferred. Furthermore, to provide easy adhesion and sealing properties, a multilayer film in which copolymer or terpolymer is formed as a skin layer on a homopolymer core layer by co-extrusion may be used as the first polyolefin layer.

[0032] The polyolefin constituting the first polyolefin layer may be recycled polyolefin, or it may be polyolefin obtained by polymerizing biomass-derived raw materials such as plants. These polyolefins may be used alone or mixed with polyolefins polymerized from conventional fossil fuels.

[0033] The polyolefin film constituting the first polyolefin layer may be a stretched film or an unstretched film. However, from the viewpoint of impact resistance, heat resistance, water resistance, dimensional stability, etc., the polyolefin film may be a stretched film. This allows the laminate to be used more suitably for applications involving hot filling. The stretching method is not particularly limited; any method is acceptable as long as a dimensionally stable film can be supplied, such as stretching by inflation, uniaxial stretching, or biaxial stretching.

[0034] The thickness of the polyolefin film is not particularly limited. Depending on the application, the thickness can be 6 to 200 μm, but from the viewpoint of obtaining excellent impact resistance and excellent gas barrier properties, it may be 9 to 50 μm or 12 to 38 μm.

[0035] Various pretreatments such as corona treatment, plasma treatment, and flame treatment may be applied to the first polyolefin layer to improve adhesion with the inorganic vapor deposition layer, provided that the barrier performance is not impaired.

[0036] (Intense layer) An adhesion layer (anchor coat layer) may be provided on the surface of the first polyolefin layer to which the inorganic vapor-deposited layer is laminated. The adhesion layer provides two effects: improved adhesion between the first polyolefin layer and the inorganic vapor-deposited layer, and improved smoothness of the polyolefin layer surface. Furthermore, improved smoothness makes it easier to deposit the inorganic vapor-deposited layer uniformly without defects, thus easily achieving high barrier properties.

[0037] The thickness of the adhesion layer is not particularly limited, but is preferably in the range of 0.01 to 5 μm, more preferably in the range of 0.03 to 3 μm, and particularly preferably in the range of 0.05 to 2 μm. When the thickness of the adhesion layer is above the lower limit, a more sufficient interlayer adhesion strength tends to be obtained, while when it is below the upper limit, the desired gas barrier properties tend to be more easily exhibited.

[0038] The adhesion layer can be formed using an anchor coating agent. Examples of anchor coating agents include polyester polyurethane resin, polyether polyurethane resin, and acrylic polyurethane resin. Of these, polyester polyurethane resin is preferred from the viewpoint of heat resistance and interlayer adhesion strength.

[0039] As for the method of forming the adhesion layer on the first polyolefin layer, known coating methods can be used without particular limitation, and examples include dipping, spraying, using a coater, printing press, brush, etc. Furthermore, examples of coaters and printing presses used in these methods and their coating methods include gravure coaters such as direct gravure, reverse gravure, kiss reverse gravure, and offset gravure, reverse roll coaters, microgravure coaters, chamber doctor combined coaters, air knife coaters, dip coaters, bar coaters, comma coaters, die coaters, etc.

[0040] The amount of adhesion layer to be applied is 1 m after the anchor coating agent has been applied and dried. 2 Mass per unit area: 0.01-5 g / m 2 Preferably, the concentration is 0.03 to 3 g / m 2 It is more preferable that the anchor coating agent is applied and dried for 1m 2 When the mass per unit area is above the lower limit, film formation tends to be sufficient, while when it is below the upper limit, it tends to dry easily and less solvent residue is likely to remain.

[0041] There are no particular limitations on the method for drying the adhesion layer, but examples include natural drying, drying in an oven set to a predetermined temperature, and using a dryer attached to the coater, such as an arch dryer, floating dryer, drum dryer, or infrared dryer. Furthermore, the drying conditions can be appropriately selected depending on the drying method. For example, when drying in an oven, it is preferable to dry at a temperature of 60 to 100°C for about 1 second to 2 minutes.

[0042] A polyvinyl alcohol-based resin may be used as the anchor coating agent. The polyvinyl alcohol-based resin can be any resin having vinyl alcohol units formed by saponification of vinyl ester units, such as polyvinyl alcohol (PVA) and ethylene-vinyl alcohol copolymer (EVOH).

[0043] Examples of PVA include resins obtained by polymerizing vinyl esters such as vinyl acetate, vinyl formate, vinyl propionate, vinyl valerate, vinyl caprate, vinyl laurate, vinyl stearate, vinyl pivalate, and vinyl versaticate individually, and then saponifying them. PVA may also be copolymerized or post-modified modified PVA. Modified PVA can be obtained, for example, by copolymerizing a vinyl ester with an unsaturated monomer copolymerizable with the vinyl ester, followed by saponification. Examples of unsaturated monomers copolymerizable with vinyl esters include olefins such as ethylene, propylene, isobutylene, α-octene, α-dodecene, and α-octadecene; hydroxyl group-containing α-olefins such as 3-buten-1-ol, 4-pentin-1-ol, and 5-hexen-1-ol; unsaturated acids such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, maleic anhydride, itaconic acid, and undecylenic acid; nitriles such as acrylonitrile and methacrylonitrile; and diacetone acrylamide. Examples include amides such as luamide and methacrylamide; olefin sulfonic acids such as ethylene sulfonic acid, allyl sulfonic acid, and methallyl sulfonic acid; vinyl compounds such as alkyl vinyl ethers, dimethylallyl vinyl ketone, N-vinylpyrrolidone, vinyl chloride, vinylethylene carbonate, 2,2-dialkyl-4-vinyl-1,3-dioxolane, glycerol monoallyl ether, and 3,4-diacetoxy-1-butene; and vinylidene chloride, 1,4-diacetoxy-2-butene, vinylene carbonate, etc.

[0044] The degree of polymerization of PVA is preferably 300 to 3000. If the degree of polymerization is less than 300, the barrier properties tend to decrease, and if it exceeds 3000, the viscosity becomes too high and the coating suitability tends to decrease. The degree of saponification of PVA is preferably 90 mol% or more, more preferably 95 mol% or more, and even more preferably 99 mol% or more. The degree of saponification of PVA may also be 100 mol% or less, or 99.9 mol% or less. The degree of polymerization and saponification of PVA can be measured in accordance with the method described in JIS K 6726 (1994).

[0045] EVOH is generally obtained by saponifying copolymers of ethylene with vinyl acid esters such as vinyl acetate, vinyl formate, vinyl propionate, vinyl valerate, vinyl caprate, vinyl laurate, vinyl stearate, vinyl pivalate, and vinyl versatate.

[0046] The degree of polymerization of EVOH is preferably 300 to 3000. If the degree of polymerization is less than 300, the barrier properties tend to decrease, and if it is greater than 3000, the viscosity becomes too high and the coating suitability tends to decrease. The degree of saponification of the vinyl ester component of EVOH is preferably 90 mol% or more, more preferably 95 mol% or more, and even more preferably 99 mol% or more. Furthermore, the degree of saponification of EVOH may be 100 mol% or less, or 99.9 mol% or less. The degree of saponification of EVOH is related to nuclear magnetic resonance ( 1 The hydrogen atoms in the vinyl ester structure and the vinyl alcohol structure are determined by performing 1H-NMR measurements and comparing the peak areas of the hydrogen atoms in the vinyl ester structure with those of the vinyl alcohol structure.

[0047] The ethylene unit content of EVOH is preferably 10 mol% or more, more preferably 15 mol% or more, even more preferably 20 mol% or more, and particularly preferably 25 mol% or more. Furthermore, the ethylene unit content of EVOH is preferably 65 mol% or less, more preferably 55 mol% or less, and even more preferably 50 mol% or less. An ethylene unit content of 10 mol% or more allows for good maintenance of gas barrier properties and dimensional stability under high humidity. On the other hand, an ethylene unit content of 65 mol% or less enhances gas barrier properties. The ethylene unit content of EVOH can be determined by NMR spectroscopy.

[0048] When using a polyvinyl alcohol-based resin as the adhesion layer, methods for forming the adhesion layer include coating with a polyvinyl alcohol-based resin solution and multilayer extrusion. In the case of multilayer extrusion, lamination may be carried out via an adhesive resin such as maleic anhydride-grafted polyethylene.

[0049] The anchor coating agent may contain a silane coupling agent from the viewpoint of improving adhesion between the substrate layer and the vapor-deposited layer. A silane coupling agent containing any organic functional group can be used, for example, one or more silane coupling agents such as vinyltrimethoxysilane, γ-chloropropylmethyldimethoxysilane, γ-chloropropyltrimethoxysilane, glycidooxypropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, and γ-methacryloxypropylmethyldimethoxysilane, or their hydrolysates, can be used.

[0050] Of these silane coupling agents, those having a functional group that reacts with the hydroxyl group of a polyol or the isocyanate group of an isocyanate compound are preferred. For example, those containing an isocyanate group, such as γ-isocyanatetopropyltriethoxysilane and γ-isocyanatetopropyltrimethoxysilane; those containing a mercapto group, such as γ-mercaptopropyltriethoxysilane; and those containing an amino group, such as γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, N-β-(aminoethyl)-γ-aminopropyltriethoxysilane, and γ-phenylaminopropyltrimethoxysilane. Furthermore, those containing an epoxy group, such as γ-glycidooxypropyltrimethoxysilane and β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, or those obtained by adding an alcohol or the like to a silane coupling agent such as vinyltrimethoxysilane or vinyltris(β-methoxyethoxy)silane to add a hydroxyl group, may also be used, and one or more of these can be used.

[0051] The amount of silane coupling agent can be 0.1 to 100 parts by mass, or 1 to 50 parts by mass, per 100 parts by mass of the resin (main component) constituting the adhesion layer.

[0052] (Inorganic vapor deposited layer) The inorganic vapor-deposited layer is provided to prevent the dissolution of fragrance components of the package contents into the first polyolefin layer. Examples of constituent materials for the inorganic vapor-deposited layer include inorganic oxides such as aluminum oxide, silicon oxide, magnesium oxide, and tin oxide. Therefore, the inorganic vapor-deposited layer can also be called an inorganic oxide layer. From the viewpoint of transparency and barrier properties, the inorganic oxide may be selected from the group consisting of aluminum oxide, silicon oxide, and magnesium oxide. Furthermore, considering printability and cost, the inorganic oxide may be selected from aluminum oxide or silicon oxide. Furthermore, from the viewpoint of excellent tensile stretchability during processing, the inorganic oxide may be silicon oxide. By using an inorganic vapor-deposited layer, high barrier properties can be obtained with a very thin layer that does not affect the recyclability of the gas barrier laminate.

[0053] When aluminum oxide is selected as the inorganic vapor deposition layer, it is desirable that the O / Al ratio be 1.4 or higher. An O / Al ratio of 1.4 or higher suppresses the content of metallic Al, making it easier to obtain good transparency. Furthermore, an O / Al ratio of 1.7 or lower is preferable. An O / Al ratio of 1.7 or lower increases the crystallinity of AlO, preventing the inorganic vapor deposition layer from becoming too hard and resulting in good tensile strength. In addition, even after molding into a packaging bag, the first polyolefin layer may shrink due to the heat during hot filling, but an O / Al ratio of 1.7 or lower allows the inorganic vapor deposition layer to easily follow this shrinkage, suppressing a decrease in barrier properties. From the viewpoint of obtaining these effects more fully, it is preferable that the O / Al ratio of the inorganic vapor deposition layer be 1.4 or higher and 1.7 or lower, and more preferably 1.5 or higher and 1.55 or lower.

[0054] When silicon oxide is selected as the inorganic vapor deposition layer, it is desirable that the O / Si ratio be 1.7 or higher. An O / Si ratio of 1.7 or higher suppresses the content of metallic Si, making it easier to obtain good transparency. Furthermore, an O / Si ratio of 2.0 or lower is preferable. An O / Si ratio of 2.0 or lower increases the crystallinity of SiO, preventing the inorganic vapor deposition layer from becoming too hard and resulting in good tensile strength. In addition, even after molding into a packaging bag, the first polyolefin layer may shrink due to hot filling, etc., but an O / Si ratio of 2.0 or lower allows the inorganic vapor deposition layer to easily follow the above shrinkage, suppressing a decrease in barrier properties. From the viewpoint of obtaining these effects more fully, it is preferable that the O / Si ratio of the inorganic vapor deposition layer be 1.75 or higher and 1.9 or lower, and more preferably 1.8 or higher and 1.85 or lower.

[0055] The O / Al and O / Si ratios of the inorganic vapor-deposited layer can be determined by X-ray photoelectron spectroscopy (XPS). For example, an X-ray photoelectron spectrometer (manufactured by JEOL Ltd., product name: JPS-90MXV) can be used as the measuring device, and a non-monochromatic MgKα (1253.6 eV) can be used as the X-ray source, with an X-ray output of 100 W (10 kV-10 mA).

[0056] When aluminum oxide is selected as the inorganic vapor deposition layer, its thickness is preferably between 5 nm and 30 nm. A thickness of 5 nm or more makes it easier to obtain sufficient gas barrier properties. Furthermore, a thickness of 30 nm or less suppresses the occurrence of cracks due to deformation caused by internal stress in the layer, thus suppressing a decrease in gas barrier properties. However, a thickness exceeding 30 nm is undesirable from an economic standpoint because it tends to increase costs due to increased material usage and longer layer formation times. From the same viewpoint as above, a thickness of 7 nm to 15 nm is more preferable.

[0057] When silicon oxide is selected as the inorganic vapor deposition layer, its thickness is preferably between 10 nm and 50 nm. A thickness of 10 nm or more allows for sufficient gas barrier properties to be obtained. Furthermore, a thickness of 50 nm or less suppresses the occurrence of cracks due to deformation caused by internal stress in the layer, thus preventing a decrease in gas barrier properties. However, a thickness exceeding 50 nm is undesirable from an economic standpoint because it tends to increase costs due to increased material usage and longer layer formation times. From the same viewpoint as above, a thickness of 20 nm or more and 40 nm is more preferable for the inorganic vapor deposition layer.

[0058] Inorganic vapor-deposited layers can be formed, for example, by vacuum deposition. Vacuum deposition can utilize either physical vapor deposition or chemical vapor deposition. Examples of physical vapor deposition include vacuum deposition, sputtering, and ion plating, but are not limited to these. Examples of chemical vapor deposition include thermal CVD, plasma CVD, and photoCVD, but are not limited to these.

[0059] In the vacuum deposition methods described above, resistance heating vacuum deposition, EB (Electron Beam) heating vacuum deposition, induction heating vacuum deposition, sputtering, reactive sputtering, dual magnetron sputtering, and plasma chemical vapor deposition (PECVD) are particularly preferred. However, considering productivity, vacuum deposition is currently the most superior method. For the heating means in vacuum deposition, it is preferable to use one of the following methods: electron beam heating, resistance heating, or induction heating.

[0060] (Gas barrier coating layer) The gas barrier coating layer is formed to prevent the dissolution of fragrance components of the package contents into the first polyolefin layer, to improve gas barrier properties, and to protect the inorganic vapor-deposited layer. Furthermore, even if minor cracks occur in the inorganic vapor-deposited layer, the gas barrier material can fill these cracks, thereby suppressing a decrease in gas barrier properties. The gas barrier coating layer can also be called an overcoat layer in relation to the anchor coat layer.

[0061] (First aspect of gas barrier coating layer) The gas barrier coating layer may include a hydroxyl group-containing polymer compound, although this is not a limitation. Specifically, the gas barrier coating layer may be a heat-dried product of a composition containing at least one of a hydroxyl group-containing polymer compound and its hydrolysate, and at least one selected from the group consisting of metal alkoxides, silane coupling agents, and their hydrolysates.

[0062] The gas barrier coating layer is formed using a composition (hereinafter also referred to as an overcoat agent) obtained by adding a hydroxyl group-containing polymer compound and a metal alkoxide and / or silane coupling agent to water or a water / alcohol mixture. The overcoat agent can be prepared, for example, by mixing a solution obtained by dissolving a water-soluble polymer, such as a hydroxyl group-containing polymer compound, in an aqueous solvent (water or a water / alcohol mixture) with a metal alkoxide and / or silane coupling agent, either directly or after prior treatment such as hydrolysis of these agents.

[0063] The overcoat agent may contain at least a silane coupling agent or its hydrolysate, from the viewpoint of better maintaining gas barrier properties after hot water treatment such as hot filling. Specifically, the overcoat agent may contain at least one of a hydroxyl group-containing polymer compound and its hydrolysate, and at least one of a silane coupling agent and its hydrolysate, or it may contain at least one of a hydroxyl group-containing polymer compound and its hydrolysate, at least one of a metal alkoxide and its hydrolysate, and at least one of a silane coupling agent and its hydrolysate.

[0064] Examples of hydroxyl group-containing polymer compounds include polyvinyl alcohol, ethylene-vinyl alcohol copolymer, polyvinylpyrrolidone, starch, methylcellulose, carboxymethylcellulose, and sodium alginate. Among these, polyvinyl alcohol (PVA) is preferred when used as an overcoat agent for a gas barrier coating layer because it exhibits particularly excellent gas barrier properties.

[0065] Examples of metal alkoxides include compounds represented by the following general formula (I). M(OR 1 )m(R 2 )nm …(I) In the above general formula (I), R 1 and R 2 Each of these is independently a monovalent organic group having 1 to 8 carbon atoms, preferably an alkyl group such as a methyl group or an ethyl group. M represents an n-valent metal atom such as Si, Ti, Al, or Zr. m is an integer from 1 to n. Note that R 1 or R 2 If there are multiple instances, R 1 Mutual or R 2 They may be the same or different.

[0066] Examples of metal alkoxides include tetraethoxysilane [Si(OC2H5)4] and triisopropoxyaluminum [Al(O-2'-C3H7)3]. Tetraethoxysilane and triisopropoxyaluminum are preferred because they are relatively stable in aqueous solvents after hydrolysis.

[0067] Examples of silane coupling agents include compounds represented by the following general formula (II). Si(OR 11 ) p (R 12 ) 3-p R 13 …(II) In the above general formula (II), R 11 R represents an alkyl group such as a methyl group or an ethyl group. 12 R represents a monovalent organic group such as an alkyl group, aralkyl group, aryl group, alkenyl group, alkyl group substituted with an acryloxy group, or alkyl group substituted with a methacryloxy group. 13 indicates a monovalent organic functional group, and p is an integer from 1 to 3. Note that R 11 or R 12 If there are multiple instances, R 11 Mutual or R 12 They may be the same or different. 13 Examples of monovalent organic functional groups represented by include monovalent organic functional groups containing a glycidyloxy group, epoxy group, mercapto group, hydroxyl group, amino group, alkyl group substituted with a halogen atom, or isocyanate group.

[0068] Examples of silane coupling agents include vinyltrimethoxysilane, γ-chloropropylmethyldimethoxysilane, γ-chloropropyltrimethoxysilane, glycidooxypropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, and γ-methacryloxypropylmethyldimethoxysilane.

[0069] Furthermore, the silane coupling agent may be a polymer of the compound represented by the above general formula (II). A trimer is preferred as the polymer, and more preferably 1,3,5-tris(3-trialkoxysilylalkyl)isocyanurate. This is a condensed polymer of 3-isocyanate alkylalkoxysilane. It is known that in 1,3,5-tris(3-trialkoxysilylalkyl)isocyanurate, the isocyanate portion loses its chemical reactivity, but the reactivity is maintained by the polarity of the nulate portion. Generally, it is added to adhesives and the like, similar to 3-isocyanate alkylalkoxylane, and is known as an adhesion improver. Therefore, by adding 1,3,5-tris(3-trialkoxysilylalkyl)isocyanurate to a hydroxyl group-containing polymer compound, the water resistance of the gas barrier coating layer can be improved by hydrogen bonding. While 3-isocyanate alkylalkoxylanes are highly reactive and have low liquid stability, 1,3,5-tris(3-trialkoxysilylalkyl)isocyanurate, although its nurate portion is not water-soluble due to its polarity, disperses easily in aqueous solutions and can maintain stable liquid viscosity. Furthermore, the water resistance performance of 3-isocyanate alkylalkoxylanes and 1,3,5-tris(3-trialkoxysilylalkyl)isocyanurate is equivalent.

[0070] 1,3,5-Tris(3-trialkoxysilylalkyl)isocyanurate may contain 3-isocyanatetopropylalkoxysilane, a raw material produced by the thermal condensation of 3-isocyanatetopropylalkoxysilane, but this does not particularly affect its function as an agent. More preferably, 1,3,5-tris(3-trialkoxysilylalkyl)isocyanurate is 1,3,5-tris(3-trialkoxysilylpropyl)isocyanurate, and more preferably, 1,3,5-tris(3-trimethoxysilylpropyl)isocyanurate. 1,3,5-tris(3-trimethoxysilylpropyl)isocyanurate is practically advantageous because the methoxy group undergoes rapid hydrolysis, and those containing a propyl group are relatively inexpensive to obtain.

[0071] The amount of metal alkoxide in the overcoat agent can be 1 to 4 parts by mass, and may be 2 to 3 parts by mass, per 1 part by mass of hydroxyl group-containing polymer compound, from the viewpoint of suppressing fragrance permeation, adhesion to the inorganic vapor deposition layer, and maintaining gas barrier properties. Similarly, the amount of silane coupling agent can be 0.01 to 1 part by mass, and may be 0.1 to 0.5 parts by mass, per 1 part by mass of hydroxyl group-containing polymer compound. When a silane compound (alkoxysilane) is used as the metal alkoxide, the amount of silane compound (metal alkoxide and silane coupling agent) in the overcoat agent can be 1 to 4 parts by mass, and may be 2 to 3 parts by mass, per 1 part by mass of hydroxyl group-containing polymer compound.

[0072] The overcoat agent may also contain isocyanate compounds or known additives such as dispersants, stabilizers, viscosity modifiers, and colorants, as needed, provided that they do not impair the gas barrier properties.

[0073] (Second aspect of gas barrier coating layer) The gas barrier coating layer may contain a polycarboxylic acid polymer crosslinked with a polyvalent metal or a polyvalent metal compound. Such a gas barrier coating layer may be formed by using a composition containing a polycarboxylic acid polymer and a composition containing a polyvalent metal or a polyvalent metal compound, and then heating and drying them, or it may be formed by heating and drying a composition containing a polycarboxylic acid polymer and a polyvalent metal or a polyvalent metal compound.

[0074] Existing polycarboxylic acid polymers can be used as the polymer. Existing polycarboxylic acid polymers are a general term for polymers having two or more carboxyl groups in their molecule. Specifically, examples include homopolymers using α,β-monoethylene unsaturated carboxylic acids as polymerizable monomers, copolymers consisting solely of α,β-monoethylene unsaturated carboxylic acids and at least two thereof, copolymers of α,β-monoethylene unsaturated carboxylic acids with other ethylenically unsaturated monomers, and acidic polysaccharides having carboxyl groups in their molecule, such as alginic acid, carboxymethylcellulose, and pectin. These polycarboxylic acid polymers can be used individually or by mixing at least two of them.

[0075] Here, typical α,β-monoethylene unsaturated carboxylic acids include acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, and crotonic acid. Typical ethylenically unsaturated monomers copolymerizable with these include ethylene, propylene, saturated vinyl carboxylate esters such as vinyl acetate, alkyl acrylates, alkyl methacrylates, alkyl itaconates, acrylonitrile, vinyl chloride, vinylidene chloride, vinyl fluoride, vinylidene fluoride, and styrene. When the polycarboxylic acid polymer is a copolymer of an α,β-monoethylene unsaturated carboxylic acid and a saturated vinyl carboxylate ester such as vinyl acetate, the saturated vinyl carboxylate portion can be converted to vinyl alcohol by further saponification and used. Furthermore, when the polycarboxylic acid polymer is a copolymer of an α,β-monoethylene unsaturated carboxylic acid and other ethylenically unsaturated monomers, from the viewpoint of the gas barrier properties and heat resistance of the resulting film, it is preferable that the copolymer composition has an α,β-monoethylene unsaturated carboxylic acid monomer composition of 60 mol% or more. The composition is more preferably 80 mol% or more, even more preferably 90 mol% or more, and most preferably 100 mol%, meaning that the polycarboxylic acid polymer is preferably a polymer consisting only of α,β-monoethylene unsaturated carboxylic acids. Furthermore, when the polycarboxylic acid polymer is a polymer consisting only of α,β-monoethylene unsaturated carboxylic acids, suitable examples include polymers obtained by polymerization of at least one polymerizable monomer selected from the group consisting of acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, and crotonic acid, and mixtures thereof. Preferably, polymers, copolymers, and / or mixtures thereof obtained by polymerization of at least one polymerizable monomer selected from acrylic acid, methacrylic acid, and maleic acid can be used. More preferably, polyacrylic acid, polymethacrylic acid, polymaleic acid, and mixtures thereof can be used. When the polycarboxylic acid polymer is a compound other than a polymer of α,β-monoethylene unsaturated carboxylic acid monomers, for example, in the case of acidic polysaccharides, alginic acid can be preferably used.

[0076] The number-average molecular weight of the polycarboxylic acid polymer is not particularly limited, but from the viewpoint of film formation, it is preferably in the range of 2,000 to 10,000,000, and more preferably in the range of 5,000 to 1,000,000.

[0077] While it is possible to use other polymers in addition to polycarboxylic acid polymers as materials constituting the gas barrier coating layer, provided that these do not impair the fragrance permeation suppression, gas barrier properties, and heat resistance of the gas barrier coating layer, it is preferable to use only polycarboxylic acid polymers.

[0078] Polyvalent metals are individual polyvalent metal atoms with a valency of 2 or higher, and polyvalent metal compounds are compounds of these atoms. Specific examples of polyvalent metals include alkaline earth metals such as beryllium, magnesium, and calcium; transition metals such as titanium, zirconium, chromium, manganese, iron, cobalt, nickel, copper, and zinc; and aluminum. Specific examples of polyvalent metal compounds include oxides, hydroxides, carbonates, organic acid salts, inorganic acid salts of the above-mentioned polyvalent metals, as well as ammonium complexes of polyvalent metals, secondary to quaternary amine complexes of polyvalent metals, and their carbonates and organic acid salts. Examples of organic acid salts include acetates, oxalates, citrates, lactates, phosphates, phosphites, hypophosphites, stearates, and monoethylene unsaturated carboxylates. Examples of inorganic acid salts include chlorides, sulfates, and nitrates. Other examples include alkyl alkoxides of polyvalent metals.

[0079] These polyvalent metals and polyvalent metal compounds can be used individually or in mixtures of at least two or more. Among these, divalent polyvalent metal compounds are preferred in terms of inhibiting fragrance permeation in the gas barrier coating layer, gas barrier properties, heat resistance, and manufacturability. More preferably, alkaline earth metals, and oxides, hydroxides, and carbonates of cobalt, nickel, copper, and zinc, as well as ammonium complexes of cobalt, nickel, copper, and zinc and their carbonates can be used. Most preferably, oxides, hydroxides, and carbonates of magnesium, calcium, copper, and zinc, as well as ammonium complexes of copper or zinc and their carbonates can be used.

[0080] Within limits that do not impair the fragrance permeation suppression, gas barrier properties, and heat resistance of the gas barrier coating layer, a metal compound consisting of a monovalent metal, such as a monovalent metal salt of a polycarboxylic acid polymer, can be used. The preferred amount of monovalent metal compound added, from the viewpoint of fragrance permeation suppression, gas barrier properties, and heat resistance of the gas barrier coating layer, is 0.2 chemical equivalents or less relative to the carboxyl groups of the polycarboxylic acid polymer. The monovalent metal compound may be partially contained within the molecules of the polyvalent metal salt of the polycarboxylic acid polymer.

[0081] The form of polyvalent metals and polyvalent metal compounds is not particularly limited. However, in the gas barrier coating layer, some or all of the polyvalent metals and polyvalent metal compounds form salts with the carboxyl groups of the polycarboxylic acid polymer. Therefore, if polyvalent metals or polyvalent metal compounds that do not participate in carboxylate salt formation are present in the gas barrier coating layer, or if the gas barrier coating layer consists of adjacent layer units containing a polycarboxylic acid polymer and a layer containing a polyvalent metal or polyvalent metal compound, it is preferable for the polyvalent metals and polyvalent metal compounds to be granular with small particle sizes from the viewpoint of transparency of the gas barrier coating layer. Furthermore, when preparing the overcoat agent for making the film, it is preferable for the polyvalent metals and polyvalent metal compounds to be granular with small particle sizes from the viewpoint of efficiency during preparation and obtaining a more uniform overcoat agent. The average particle size of the polyvalent metals and polyvalent metal compounds is preferably 5 μm or less, more preferably 1 μm or less, and most preferably 0.1 μm or less.

[0082] In a gas barrier coating layer, the amount of polyvalent metals and polyvalent metal compounds relative to the amount of polycarboxylic acid polymer is preferably such that, from the viewpoint of suppressing fragrance permeation, gas barrier properties, and heat resistance of the gas barrier coating layer, if the gas barrier coating layer has at least one layer unit in which a layer containing a polycarboxylic acid polymer and a layer containing a polyvalent metal or polyvalent metal compound are adjacent, the total amount of polyvalent metals and polyvalent metal compounds relative to the total amount of carboxyl groups contained in those layers is 0.2 chemical equivalents or more, based on all adjacent layers and the sum of the layers, i.e., the total amount of polyvalent metals and polyvalent metal compounds relative to the total amount of carboxyl groups contained in those layers is 0.2 or more. Furthermore, if the gas barrier coating layer contains a mixture containing a polycarboxylic acid polymer, a polyvalent metal, or a polyvalent metal compound, it is preferable that the amount of polyvalent metal or polyvalent metal compound is 0.2 chemical equivalents or more relative to all carboxyl groups of the polycarboxylic acid polymer. The amount of polyvalent metals and polyvalent metal compounds is more preferably 0.5 chemical equivalents or more for both of the above gas barrier coating layers, and in addition to the above viewpoint, from the viewpoint of formability and transparency of the gas barrier coating layer, it is in the range of 0.8 chemical equivalents or more and 10 chemical equivalents or less, most preferably 1 chemical equivalent or more and 5 chemical equivalents or less.

[0083] This gas barrier coating layer, composed of a polycarboxylic acid polymer / polyvalent metal or polyvalent metal compound, may also contain a silicon-containing compound. The silicon-containing compound is at least one silicon-containing compound selected from the group consisting of silane coupling agents represented by the following general formula (1), their hydrolysates, and their condensates. This improves adhesion to the inorganic vapor-deposited layer, and enhances heat resistance, water resistance, etc., even in small amounts. R 1 Si(OR 2 )3···(1) In formula (1), R 1 R is an organic group containing a glycidyloxy group or an amino group. 2 It is an alkyl group, and has 3 R 2 These may be the same or different. However, in general formula (1), R 1Examples of organic groups in this include glycidyloxyalkyl groups and aminoalkyl groups. 2 The alkyl group is preferably an alkyl group having 1 to 6 carbon atoms, and a methyl group or an ethyl group is particularly preferred.

[0084] Specific examples of silane coupling agents include γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-aminopropyltrimethoxysilane, and γ-aminopropyltriethoxysilane. Among these, γ-glycidoxypropyltrimethoxysilane and γ-aminopropyltrimethoxysilane are preferred.

[0085] The silicon-containing compound may be the silane coupling agent itself, a hydrolyzed product of the silane coupling agent, or a condensate thereof.

[0086] As hydrolysates, the three ORs in general formula (1) 2 Examples include those in which at least one of the groups becomes an OH group. Condensed products include those in which the Si-OH groups of at least two hydrolysis molecules condense to form a Si-O-Si bond. Furthermore, products formed by the condensation of hydrolysis products of silane coupling agents can be called hydrolysis condensates.

[0087] Furthermore, silane coupling agents can be used after undergoing hydrolysis and condensation reactions, for example, using the sol-gel method. Normally, silane coupling agents readily undergo hydrolysis and readily undergo condensation reactions in the presence of acids and alkalis; therefore, it is rare for them to exist alone, their hydrolysates alone, or their condensates alone. In other words, they are usually found in mixtures of silane coupling agents, their hydrolysates, and their condensates. Hydrolysates also include partially hydrolyzed and completely hydrolyzed products.

[0088] The overcoat agent can be applied by methods such as dipping, roll coating, gravure coating, reverse gravure coating, air knife coating, comma coating, die coating, screen printing, spray coating, and gravure offset. The coating film obtained by applying the overcoat agent can be dried by methods such as hot air drying, hot roll drying, high-frequency irradiation, infrared irradiation, UV irradiation, or a combination thereof.

[0089] The temperature at which the above coating film is dried can be, for example, 50 to 150°C, and preferably 70 to 100°C. By keeping the drying temperature within this range, the occurrence of cracks in the inorganic vapor deposition layer and the gas barrier coating layer can be further suppressed, and excellent barrier properties can be achieved.

[0090] The gas barrier coating layer may be formed using an overcoat agent containing a hydroxyl group-containing polymer compound (e.g., polyvinyl alcohol-based resin) and a silane compound. Acid catalysts, alkali catalysts, photoinitiators, etc., may be added to the overcoat agent as needed.

[0091] Examples of silane compounds include silane coupling agents, polysilazanes, and siloxanes. Specifically, examples include tetramethoxysilane, tetraethoxysilane, glycidoxypropyltrimethoxysilane, acryloxypropyltrimethoxysilane, and hexamethyldisilazane.

[0092] The thickness of the gas barrier coating layer is preferably 50 to 1000 nm, and more preferably 100 to 500 nm. When the thickness of the gas barrier coating layer is 50 nm or more, sufficient gas barrier properties tend to be obtained, and when it is 1000 nm or less, sufficient flexibility tends to be maintained.

[0093] (Third aspect of gas barrier coating layer) The gas barrier coating layer may also be a layer having adhesive properties. Such a layer can be called an adhesive gas barrier coating layer. The adhesive gas barrier coating layer may be a cured product of an adhesive composition containing a resin having at least one aromatic ring and one aliphatic ring. Within the cured product (cured film), the cyclic structures of the aromatic ring or aliphatic ring exist in parallel, making it easier to suppress the permeation of fragrances.

[0094] The glass transition temperature of the cured product is preferably between 40°C and 70°C. Below 40°C, the fragrance permeation suppression effect cannot be obtained, and above 70°C, flexibility at room temperature is weak, and adhesion to adjacent layers is poor, which may reduce adhesion strength. An example of an adhesive that satisfies these conditions is a two-component curing adhesive consisting of an epoxy resin and an amine-based epoxy resin curing agent. The epoxy resin that can be used may be an alicyclic compound, an aromatic compound, or a heterocyclic compound. Specific examples of epoxy resins include at least one resin selected from the following: epoxy resins having a glycidylamino group derived from metaxylylenediamine, epoxy resins having a glycidylamino group derived from 1,3-bis(aminomethyl)cyclohexane, epoxy resins having a glycidylamino group derived from diaminodiphenylmethane, epoxy resins having a glycidylamino group and / or glycidyloxy group derived from para-aminophenol, epoxy resins having a glycidyloxy group derived from bisphenol A, epoxy resins having a glycidyloxy group derived from bisphenol F, epoxy resins having a glycidyloxy group derived from phenol novolac, and epoxy resins having a glycidyloxy group derived from resorcinol. Among these, epoxy resins having a glycidylamino group derived from metaxylylenediamine are particularly preferred.

[0095] Examples of adhesive compositions include an adhesive comprising a polyester or polyester polyurethane resin obtained by using an ortho-oriented aromatic dicarboxylic acid or its anhydride as the polyvalent carboxylic acid of the monomer component constituting the polyester, which has two or more hydroxyl groups in one molecule as a functional group, and a polyisocyanate containing at least one of diphenylmethane diisocyanate, polymeric diphenylmethane diisocyanate, and derivatives thereof.

[0096] Specific examples of gas barrier adhesives include "Maxive" manufactured by Mitsubishi Gas Chemical Company and "Paslim" manufactured by DIC Corporation.

[0097] The oxygen permeability of the adhesive gas barrier coating layer is 150 cc / m². 2 It may be less than or equal to 100cc / m². 2 It may be less than or equal to 80cc / m². 2 It may be less than or equal to 50cc / m². 2 It is acceptable for the oxygen permeability to be below day·atm. Having the oxygen permeability within the above range makes it easier to improve gas barrier properties.

[0098] The thickness of the adhesive gas barrier coating layer may be 50 times or more the thickness of the inorganic vapor-deposited layer. Having a thickness within this range provides the gas barrier coating layer with cushioning properties to mitigate external impacts, making it easier to suppress cracking of the inorganic vapor-deposited layer, and enabling higher levels of prevention of dissolution of fragrance components into the first polyolefin layer, as well as gas barrier properties. From the viewpoint of maintaining the flexibility of the packaging material, processability, and cost, the thickness of the adhesive gas barrier coating layer may be 300 times or less the thickness of the inorganic vapor-deposited layer. The thickness of the adhesive gas barrier coating layer may be, for example, 0.1 to 20 μm, 0.5 to 10 μm, or 1 to 5 μm.

[0099] The above-mentioned material (gas barrier adhesive) for forming the adhesive gas barrier coating layer can be applied by methods such as bar coating, dipping, roll coating, gravure coating, reverse coating, air knife coating, comma coating, die coating, screen printing, spray coating, and gravure offset. The temperature for drying the coating film may be, for example, 30 to 200°C or 50 to 180°C. The temperature for curing the coating film may be, for example, room temperature to 70°C or 30 to 60°C. By keeping the drying and curing temperatures within the above ranges, the occurrence of cracks in the inorganic vapor deposition layer and the adhesive gas barrier coating layer can be further suppressed, and the dissolution of fragrance components into the first polyolefin layer and gas barrier properties can be achieved at a higher level.

[0100] From the viewpoint of protecting the inorganic vapor-deposited layer, an adhesive gas barrier coating layer can be formed directly on the inorganic vapor-deposited layer, but other layers such as a printed layer or a gas barrier coating layer (without adhesive properties) may be present between the two layers.

[0101] (Printing layer) A printing layer can be provided on the surface of the first polyolefin layer facing the inorganic vapor deposition layer, on the surface of the first polyolefin layer opposite the inorganic vapor deposition layer, or on the inorganic vapor deposition layer itself. The printing layer is provided in a position visible from the outside of the laminate for the purpose of displaying information about the contents, identifying the contents, or improving the design of the packaging bag. The printing method and printing ink are not particularly limited and are appropriately selected from known printing methods and printing inks, taking into consideration factors such as suitability for printing on the film, design aspects such as color tone, adhesion, and safety as a food container. Examples of printing methods that can be used include gravure printing, offset printing, gravure offset printing, flexographic printing, and inkjet printing. Among these, gravure printing is preferred from the viewpoint of productivity and high resolution of the image.

[0102] (Second polyolefin layer) The second polyolefin layer is composed of a material with a lower melting point than the constituent materials of the first polyolefin layer and possesses heat-sealing properties. Therefore, the second polyolefin layer can also be called a sealant layer.

[0103] The first polyolefin layer and the second polyolefin layer may be made of different materials, but from the viewpoint of ease of reforming after melting the resin material, it is preferable that they be made of the same material. Here, "made of the same material" means, for example, that both layers are made of polyethylene or both are made of polypropylene.

[0104] If the first polyolefin layer is polyethylene, linear low-density polyethylene (LLDPE) can be used as the second polyolefin layer. Furthermore, for purposes such as providing rigidity, a laminated film with a high-density polyethylene (HDPE) or medium-density polyethylene (MDPE) inorganic vapor-deposited layer and a low-density polyethylene (LDPE) sheet seal layer can also be used as the second polyolefin layer.

[0105] If the first polyolefin layer is polypropylene, the second polyolefin layer can be made of ethylene-based resins such as low-density polyethylene resin (LDPE), medium-density polyethylene resin (MDPE), linear low-density polyethylene resin (LLDPE), ethylene-vinyl acetate copolymer (EVA), ethylene-α-olefin copolymer, or ethylene-(meth)acrylic acid copolymer, or a blend of polyethylene and polybutene resin, or polypropylene-based resins such as homopolypropylene resin (PP), propylene-ethylene random copolymer, propylene-ethylene block copolymer, or propylene-α-olefin copolymer.

[0106] The polyolefin film constituting the second polyolefin layer may contain various additives such as flame retardants, slip agents, antiblocking agents, antioxidants, light stabilizers, and tackifiers.

[0107] The thickness of the second polyolefin layer is determined by factors such as the mass of the contents and the shape of the packaging bag, but a thickness of approximately 30 to 150 μm is generally preferred.

[0108] As a means of laminating a first polyolefin layer having an inorganic vapor deposition layer and a gas barrier coating layer formed thereon with a second polyolefin layer having heat-sealing properties, any known lamination method can be used, such as a dry lamination method using an adhesive such as a one-component or two-component curing urethane adhesive, a non-solvent dry lamination method using a solvent-free adhesive, or an extrusion lamination method in which polyolefin resins such as polyethylene or polypropylene are heated and melted, extruded in a curtain-like manner, and then laminated. From the viewpoint of environmental considerations, adhesives containing biomass-derived or biodegradable polymer components may be used.

[0109] When using an adhesive gas barrier coating layer, a first polyolefin layer on which an inorganic vapor-deposited layer is formed and a second polyolefin layer having heat-sealing properties can be laminated using the adhesive gas barrier coating layer.

[0110] As described above, the films constituting the packaging material can all be polyolefin films. Such packaging materials can be described as monomaterials made from a single material with excellent recyclability. From this perspective, the total mass of components other than polyolefin components (for example, components such as the adhesion layer, inorganic vapor deposition layer, gas barrier coating layer, adhesive layer, and printing layer) relative to the total mass of the packaging material can be 10% by mass or less, 7.5% by mass or less, or 5.0% by mass or less.

[0111] The packaging material may include, in addition to the first polyolefin layer, other resin layers as a base material. The other resin layer may be a polyolefin layer. Depending on the purpose, the other resin layer can be selected from a film with high heat resistance, a film with easy tearing properties such as uniaxial stretching, or a film with a nylon layer co-extruded to provide puncture resistance.

[0112] <Packaging bags and packaging bodies> A packaging bag can be obtained by heat-sealing the second polyolefin layers of the packaging material obtained in this way. A package can be obtained by filling the packaging bag obtained in this way with contents containing esters or terpenes as fragrance and sealing it. [Examples]

[0113] The present disclosure will be explained in more detail below with experimental examples, but the present disclosure is not limited to these experimental examples.

[0114] (Preparation of anchor coating agent) An acrylic polyol and tolylene diisocyanate were mixed so that the number of NCO groups in the tolylene diisocyanate was equal to the number of OH groups in the acrylic polyol, and the mixture was diluted with ethyl acetate to a total solid content (total amount of acrylic polyol and tolylene diisocyanate) of 5% by mass. To the diluted mixture, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane was added in an amount of 5 parts by mass per 100 parts by mass of the total amount of acrylic polyol and tolylene diisocyanate, and the mixture was then prepared by mixing.

[0115] (Preparation of overcoat agent (1)) Overcoat agent (1) was prepared by mixing the following solutions A, B, and C in a mass ratio of 70 / 20 / 10, respectively. Solution A: A hydrolysis solution with a solid content of 5% by mass (SiO2 equivalent) obtained by adding 72.1 g of 0.1 N hydrochloric acid to 17.9 g of tetraethoxysilane (Si(OC2H5)4) and 10 g of methanol, and stirring for 30 minutes. Solution B: 5% by mass of polyvinyl alcohol in water / methanol solution (water:methanol mass ratio is 95:5). Solution C: A hydrolysis solution obtained by diluting 1,3,5-tris(3-trimethoxysilylpropyl) isocyanurate with a mixture of water and isopropyl alcohol (water:isopropyl alcohol mass ratio is 1:1) to a solid content of 5% by mass.

[0116] (Preparation of overcoat agent (2)) To prepare an aqueous polyacrylic acid solution, 50 g of Aron A-10H polyacrylic acid (number average molecular weight: 200,000) manufactured by Toagosei Co., Ltd. was mixed with 200 g of water. Then, 1.5 g of zinc oxide fine particle aqueous dispersion manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. was added, and the mixture was stirred at room temperature for 2 days to prepare the overcoat agent (2-1). Overcoat agent (2-2) was prepared by mixing 100g of zinc oxide fine particle aqueous dispersion ZE143 manufactured by Sumitomo Osaka Cement Co., Ltd. with 1g of hardening agent Liofol HAERTER UR 5889-21 manufactured by Henkel.

[0117] (Preparation of overcoat agent (3)) A polyacrylic acid solution was prepared by adding 10 g of polyacrylic acid jurimer AC-10LP (number average molecular weight: 50,000) manufactured by Toagosei Co., Ltd. to 100 g of isopropyl alcohol. A zinc oxide dispersion was prepared by dispersing 100g of zinc oxide FINEX-30 manufactured by Sakai Chemical Industry Co., Ltd. and 15g of DA-325 manufactured by Kusumoto Chemical Co., Ltd. as a surfactant in 220g of isopropyl alcohol. Overcoat agent (3) was prepared by mixing 80 parts by mass of the above polyacrylic acid solution with 20 parts by mass of zinc oxide dispersion.

[0118] (Preparation of overcoat agent (4)) Overcoat agent (4) was prepared by mixing overcoat agent (1) solutions A, B, and C in a mass ratio of 40 / 50 / 10, respectively.

[0119] (Preparation of the overcoat agent (5)) To 23 parts by mass of a solvent prepared by mixing ethyl acetate and methanol in a mass ratio of 1:1, 16 parts by mass of Maxive C93T manufactured by Mitsubishi Gas Chemical Company and 5 parts by mass of Maxive M-100 manufactured by Mitsubishi Gas Chemical Company were mixed to prepare an overcoat agent (5).

[0120] (Preparing the adhesive) A urethane-based adhesive was prepared by mixing 100 parts by mass of Takelac A525 manufactured by Mitsui Chemicals with 11 parts by mass of Takenate A52 manufactured by Mitsui Chemicals and 84 parts by mass of ethyl acetate.

[0121] (Example 1) The above-mentioned anchor coating agent was applied to the corona-treated surface of unstretched high-density polyethylene (HDPE) with a thickness of 32 μm by gravure coating and dried to form an anchor coating layer with a thickness of 0.1 μm. A transparent inorganic deposition layer (alumina deposition layer) made of aluminum oxide with a thickness of 10 nm was formed using an electron beam heating vacuum deposition apparatus. The O / Al ratio of the alumina deposition layer was 1.5. An overcoat agent (1) was applied to the alumina vapor-deposited layer by gravure coating and dried to form an overcoat layer with a thickness of 0.3 μm. A 40 μm thick sealant film made of linear low-density polyethylene (LLDPE) was laminated onto the overcoat layer using a dry lamination method with a urethane-based adhesive to obtain a laminate.

[0122] (Example 2) As an inorganic vapor deposition layer, a transparent inorganic vapor deposition layer (silica vapor deposition layer) made of silicon oxide with a thickness of 30 nm was formed using an electron beam heating vacuum deposition apparatus. The O / Si ratio of the silica vapor deposition layer was 1.8. Except for this, the laminate was obtained in the same manner as in Example 1.

[0123] (Example 3) A laminate was obtained in the same manner as in Example 2, except that a uniaxially oriented high-density polyethylene (HDPE) with a thickness of 25 μm was used as the base material.

[0124] (Example 4) A laminate was obtained in the same manner as in Example 2, except that a 20 μm thick stretched polypropylene (OPP) was used as the base material and a 50 μm thick unstretched polypropylene (CPP) film was used as the sealant film.

[0125] (Example 5) Polypropylene and EVOH were co-extruded with an adhesive resin in between, and sequentially stretched to obtain a multilayer film having a 1 μm layer of EVOH as an anchor coat layer on an 18 μm layer of stretched polypropylene (OPP). A transparent inorganic vapor-deposited layer (silica vapor-deposited layer) made of silicon dioxide with a thickness of 30 nm was formed on the EVOH surface using a vacuum deposition apparatus with electron beam heating. The O / Si ratio of the silica vapor-deposited layer was 1.8. An overcoat agent (1) was applied to the silica vapor-deposited layer by gravure coating and dried to form an overcoat layer with a thickness of 0.3 μm. A 50 μm thick sealant film made of unstretched polypropylene (CPP) was laminated onto the overcoat layer using a dry lamination method with a urethane-based adhesive to obtain a laminate.

[0126] (Example 6) An overcoat agent (5) was applied to the silica vapor-deposited layer by dry lamination and dried to form an adhesive gas barrier coating layer with a thickness of 2.5 μm. A sealant film with a thickness of 40 μm made of linear low-density polyethylene (LLDPE) was laminated through this adhesive gas barrier coating layer. Except for this, the laminate was obtained in the same manner as in Example 2.

[0127] (Example 7) An overcoat agent (5) was applied to the silica vapor-deposited layer by dry lamination and dried to form an adhesive gas barrier coating layer with a thickness of 2.5 μm. A 50 μm thick layer of unstretched polypropylene (CPP) was laminated through this adhesive gas barrier coating layer. Except for this, the laminate was obtained in the same manner as in Example 4.

[0128] (Example 8) A laminate was obtained in the same manner as in Example 1, except that a 20 μm thick stretched polypropylene (OPP) was used as the base material, overcoat agents (2-1) and (2-2) were applied sequentially by gravure coating and dried to form a 0.6 μm thick overcoat layer (a layer containing polyacrylic acid crosslinked with zinc oxide), and an unstretched polypropylene (CPP) film with a thickness of 50 μm was used as the sealant film.

[0129] (Example 9) A laminate was obtained in the same manner as in Example 8, except that the overcoat agent (3) was applied by gravure coating and dried to form an overcoat layer with a thickness of 0.4 μm.

[0130] (Example 10) A laminate was obtained in the same manner as in Example 4, except that the overcoat agent (4) was applied by gravure coating and dried to form an overcoat layer with a thickness of 0.4 μm.

[0131] (Comparative Example 1) A laminate was obtained in the same manner as in Example 1, except that an overcoat layer was not provided.

[0132] (Comparative Example 2) A laminate was obtained in the same manner as in Example 2, except that an overcoat layer was not provided.

[0133] (Comparative Example 3) A laminate was obtained in the same manner as in Example 1, except that the anchor coat layer, inorganic vapor deposition layer, and overcoat layer were not provided.

[0134] (Comparative Example 4) A laminate was obtained in the same manner as in Example 4, except that the anchor coat layer, inorganic vapor deposition layer, and overcoat layer were not provided.

[0135] (Comparative Example 5) A laminate was obtained in the same manner as in Example 5, except that an inorganic vapor deposition layer and an overcoat layer were not provided.

[0136] (Comparative Example 6) A laminate was obtained by laminating a 40 μm thick sealant film made of linear low-density polyethylene (LLDPE) onto a corona-treated surface of 12 μm thick polyethylene terephthalate (PET) using a dry lamination method with a urethane-based adhesive.

[0137] [Method for measuring oxygen permeability] The oxygen permeability (OTR) of the laminates obtained in each example was measured using an oxygen permeability meter (MOCON, product name: OX-TRAN2 / 20) under conditions of 30°C and 70% relative humidity. The oxygen permeability of all samples except Comparative Examples 3-5 was measured in accordance with JIS K-7126, Method B (isobaric method). The oxygen permeability of Comparative Examples 3-5 was measured using an oxygen permeability meter (GTR Tech, product name: GTR-3000) in accordance with the differential pressure method. The results are shown in Table 1.

[0138] [Method for measuring water vapor transmission] The water vapor transmission rate (WTR) of the laminates obtained in each example was measured using a water vapor transmission rate measuring device (MOCON, product name: PERMATRAN-W 3 / 33) under conditions of 40°C and 90% relative humidity. Water vapor transmission rate was measured in accordance with JIS K-7126, Method B (isobaric method). The results are shown in Table 1.

[0139] [Table 1]

[0140] [Evaluation of fragrance component permeability inhibition] (Sensory evaluation) From the laminate obtained in each example, a 100mm x 100mm square sample was cut out. Two of the cut-out samples were placed on top of each other so that their sealant films faced each other, and a pouch-like structure was formed by impulse sealing on three sides to obtain a packaging bag. The resulting packaging bags were filled with either Unilever's "Lux Super Rich Shine Damage Repair Shampoo" as shampoo (containing esters such as ethyl methylbutyrate, ethyl 2-methylvalerate, hexyl acetate, allyl hexanoate, allyl heptanoate, benzyl acetate, and terpenes such as limonene as fragrance components) or P&G's "Lenor HAPPINESS Antique Rose & Floral Scent" as fabric softener (containing esters such as ethyl methylbutyrate, ethyl 2-methylbutyrate, isoamyl acetate, ethyl 2-methylvalerate, hexyl acetate, allyl hexanoate, allyl heptanoate, α-methylbenzyl acetate, benzyl acetate, β-pinene, allyl cyclohexanepropionate, 2-phenoxyethyl isobutyrate, and terpenes such as limonene, α-terpineol, β-citronellol, myrcene as fragrance components), and sealed. The seal width was 5 mm (internal surface area 9 cm x 9 cm). This resulted in a package comprising a packaging bag and contents containing fragrance packaged inside the packaging bag. The resulting packaging was sealed in an aluminum bag made of PET / aluminum foil / LLDPE along with 140cc of air and stored at 40°C for 10 days. After storage, a portion of the aluminum bag was opened, and a sensory evaluation was conducted by smelling the product. The evaluation was performed based on the following criteria. The results are shown in Table 3. ---: I can't detect any fragrance at all. --: I can barely smell any fragrance. -: I don't really notice the scent of the fragrance components. +: I can smell the fragrance. ++: I strongly smell the fragrance components. +++: The fragrance is very strong.

[0141] (Qualitative analysis of fragrance components) A package was obtained in the same manner as described above for sensory evaluation. The obtained package was sealed in an aluminum bag with 140cc of air and stored at 40°C for 10 days. 1 mL of gas from the aluminum bag after storage was withdrawn using a gas-tight syringe, and qualitative analysis of the components in the air, and as an example, qualitative analysis of hexyl acetate, was performed by GC / MS under the conditions shown in Table 2. A gas chromatograph / mass spectrometer (Agilent Technologies, model number: GC6890 / MSD5973) was used for the measurements. For the identification of fragrance components, 0.01 g of the contents containing fragrance (shampoo or fabric softener) was placed in a 20 mL vial and heated at 60°C for 20 minutes. Then, the gas in the gas phase was withdrawn using a gas-tight syringe and identified by GC / MS. The results are shown in Table 3. In Table 3, the fragrance component cut-off rates for Examples 1-3, 6, and Comparative Examples 1-2 were calculated by dividing the GC peak area value of each example by the GC peak area value of Comparative Example 3 (all are all PE packaging materials. The fragrance component cut-off rate for Comparative Example 3 is specified as 0%). Similarly, for Examples 4, 7-10, the fragrance component reduction rate was calculated based on Comparative Example 4 (all using all-PP packaging materials), and for Example 5, it was calculated based on Comparative Example 5 (all using all-PP / EVOH packaging materials).

[0142] [Table 2]

[0143] (Quantitative analysis of hexyl acetate) 0.1 μL of hexyl acetate was dropped into a 140 mL mayonnaise bottle, the lid was closed, and the bottle was heated in an oven at 40°C for 30 minutes. Then, 1 mL of gas was withdrawn from the mayonnaise bottle using a gas-tight syringe and subjected to GC / MS analysis. A calibration curve was created using the peak area values ​​in the ion chromatogram extracted at m / z=56. Using this calibration curve, the amount of hexyl acetate was quantified from the peak area values ​​at m / z=56 obtained from GC / MS analysis for each sample. The results are shown in Table 3.

[0144] Although quantitative analysis was not performed for terpenes (focusing on limonene and citronellol as examples), the total peak area values ​​in the qualitative analysis were significantly smaller in the examples compared to the comparative examples.

[0145] [Table 3] [Industrial applicability]

[0146] The packaging material according to this disclosure has excellent permeability suppression properties for fragrance components and can suitably package contents containing fragrances. Furthermore, the packaging material according to this disclosure can have a polyolefin content of 90% by mass or more of the total packaging material and is recyclable. [Explanation of Symbols]

[0147] 1...First polyolefin layer, 2...Inorganic vapor-deposited layer, 3...Gas barrier coating layer, 4...Second polyolefin layer, 10...Packaging material.

Claims

1. A packaging material for packaging contents containing fragrances, A packaging material comprising, in this order, a first polyolefin layer, an inorganic vapor-deposited layer, a gas barrier coating layer, and a second polyolefin layer having heat-sealing properties.

2. The packaging material according to claim 1, wherein the gas barrier coating layer is a heat-dried product of a composition containing at least one of a hydroxyl group-containing polymer compound and its hydrolysate, and at least one selected from the group consisting of metal alkoxides, silane coupling agents, and their hydrolysates.

3. The packaging material according to claim 1, wherein the gas barrier coating layer contains a polycarboxylic acid polymer crosslinked with a polyvalent metal or a polyvalent metal compound.

4. The packaging material according to claim 1, wherein the gas barrier coating layer is a cured product of an adhesive composition containing a resin having at least an aromatic ring and an aliphatic ring.

5. The packaging material according to any one of claims 1 to 4, wherein the inorganic vapor deposition layer comprises at least one of aluminum oxide and silicon oxide.

6. The packaging material according to any one of claims 1 to 5, wherein the first polyolefin layer and the second polyolefin layer are made of the same material.

7. The packaging material according to any one of claims 1 to 6, wherein the first polyolefin layer and the second polyolefin layer are made of polyethylene.

8. The packaging material according to any one of claims 1 to 6, wherein the first polyolefin layer and the second polyolefin layer are made of polypropylene.

9. A packaging bag formed from the packaging material described in any one of claims 1 to 8.

10. A packaging body comprising a packaging bag according to claim 9, and contents containing a fragrance packaged inside the packaging bag.

11. The packaging according to claim 10, wherein the fragrance comprises at least one of esters and terpenes.

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