JP2008132761A - Gas barrier film, packaging material, and package - Google Patents

Abstract

The present invention provides a transparent gas barrier film in which a decrease in adhesion between a plastic substrate film on which an inorganic oxide layer is formed and a heat-sealable resin layer is less likely to occur.
A transparent gas barrier film includes a plastic base film and a polyester urethane formed on one main surface of the base film and having an aromatic carboxylic acid group and an aliphatic carboxylic acid group. The primer layer 112 and the inorganic oxide layer 113 formed on the primer layer by a vapor deposition method are provided.
[Selection] Figure 1

Description

  The present invention relates to a gas barrier film, a packaging material, and a packaging body, and particularly relates to a transparent gas barrier film, a transparent packaging material, and a packaging body using the transparent packaging material.

  For packaging foods, pharmaceuticals and precision electronic parts, a packaging material having excellent gas barrier properties may be used. For example, when food is packaged with a high gas barrier packaging material, it is possible to prevent oxidation of fats and oils contained in the food, change in its moisture content, dissipation of flavor components, and the like. In addition, when a pharmaceutical product is packaged with a high gas barrier packaging material, the active ingredient can be prevented from being altered or dissipated. When an electronic component is packaged with a high gas barrier packaging material, corrosion of the metal, poor insulation, etc. Can be prevented.

  The high gas barrier packaging material has a multilayer structure including a gas barrier layer. Examples of the gas barrier layer include a metal foil such as an aluminum foil, a polyvinylidene chloride (PVDC) layer, a saponified ethylene-vinyl alcohol copolymer (EVOH) layer, and a polycondensation reaction of metaxylenediamine and adipic acid. A layer made of nylon MXD6, the resulting polyamide, is used. These high gas barrier packaging materials show some relatively high gas barrier properties but have some drawbacks.

  For example, a high gas barrier packaging material containing a metal foil exhibits excellent gas barrier properties regardless of the environment such as temperature and humidity. However, the package formed using this packaging material cannot visually recognize the contents, must be treated as non-combustible when discarded, cannot use a metal detector for inspection of foreign matter after the contents are put in, etc. There are drawbacks. Moreover, the packaged product in which the contents are packaged by this package is not suitable for microwave heating.

  The high gas barrier packaging material including the PVDC layer is inexpensive and has a relatively high gas barrier property. However, this packaging material may generate harmful gases when incinerated.

  The high gas barrier packaging material including the EVOH layer or the nylon MXD6 layer has a large environmental dependency of the gas barrier property. In particular, in a high temperature and high humidity environment, the gas barrier property is remarkably deteriorated.

  In Patent Documents 1 and 2, a gas barrier film formed by forming an inorganic oxide layer made of silicon oxide, aluminum oxide, or magnesium oxide on a plastic substrate film by a vapor deposition method such as vacuum evaporation or sputtering. Is described. This gas barrier film can be formed transparent and has excellent gas barrier properties. Therefore, this gas barrier film is suitable as a high gas barrier packaging material.

  By the way, this gas barrier film is rarely used alone. Usually, this gas barrier film is laminated with another film or formed with a printing layer. For example, the gas barrier film and the heat-sealable resin layer may be laminated so that the inorganic oxide layer is interposed between the plastic substrate film and the heat-sealable resin layer. The present inventor has found that, for example, a packaging material adopting such a structure can cause the following problems when making the present invention.

  For example, if a package made of this packaging material is used to package contents such as food, and the resulting package is subjected to boiling sterilization, delamination may occur in part of the packaging material due to the penetration of water vapor and the like. May occur. In this case, in addition to the poor appearance, the gas barrier property is lowered at the portion where delamination is caused, and the contents are deteriorated at an early stage.

  In addition, if a precision electronic component is packaged with a package made of this packaging material and the resulting package is left in a high-temperature and high-humidity environment for a long time, the plastic substrate The adhesion between the film and the heat-sealable resin layer may be significantly reduced.

In addition, when the contents containing flavor components are contained in a package made of this packaging material, and the resulting packaged product is subjected to a storage test, the plastic base film and heat seal are caused by the penetration of the flavor components. Adhesiveness with the conductive resin layer may be significantly reduced.
U.S. Pat. No. 3,442,686 JP 49-041469 A

  An object of the present invention is to make it difficult for a decrease in adhesiveness between a plastic substrate film on which an inorganic oxide layer is formed and a heat-sealable resin layer.

  According to the first aspect of the present invention, a primer layer comprising a plastic base film and a polyester urethane formed on one main surface of the base film and having an aromatic carboxylic acid group and an aliphatic carboxylic acid group. And a transparent gas barrier film comprising an inorganic oxide layer formed by a vapor deposition method on the primer layer.

  According to the second aspect of the present invention, the gas barrier film according to the first aspect and the heat-sealable resin bonded to the gas barrier film and facing the plastic substrate film with the inorganic oxide layer interposed therebetween A transparent packaging material comprising a layer is provided.

  According to the 3rd side surface of this invention, the packaging body characterized by having comprised the packaging material which concerns on a 2nd side surface is provided.

  According to this invention, it becomes possible to make it difficult to produce the fall of the adhesiveness of the plastic base film which formed the inorganic oxide layer, and a heat-sealable resin layer.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In addition, in each figure, the same referential mark is attached | subjected to the component which exhibits the same or similar function, and the overlapping description is abbreviate | omitted.

FIG. 1 is a cross-sectional view schematically showing a transparent packaging material according to one embodiment of the present invention.
The transparent packaging material 10 includes a transparent gas barrier film 11, an adhesive layer 12, and a heat sealable resin layer 13.

  The transparent gas barrier film 11 includes a plastic substrate film 111, a primer layer 112, an inorganic oxide layer 113, and a gas barrier film 114. Note that the term “film” and the term “sheet” may be properly used depending on the thickness, but the term “film” is used here regardless of the thickness.

  The plastic substrate film 111 is a transparent film. Examples of the material of the plastic substrate film 111 include polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, polyamide, polyethylene, polypropylene, polystyrene, polyvinyl chloride, polyvinylidene chloride, polycarbonate, polyacrylonitrile, polyimide, and ethylene-vinyl alcohol. A copolymer, cellophane, or the like can be used. The plastic base film 111 may contain additives and / or stabilizers such as an antistatic agent, an ultraviolet absorber, a plasticizer, and a lubricant.

  The plastic substrate film 111 may be either an unstretched film or a stretched film. In consideration of mechanical strength and dimensional stability, it is advantageous to use a stretched film such as a uniaxially stretched film and a biaxially stretched film, particularly a biaxially stretched film. For example, as the plastic substrate film 111, a biaxially stretched polyethylene terephthalate film, a biaxially stretched polyamide film, or a biaxially stretched polypropylene film may be used.

  Although there is no restriction | limiting in the thickness of the plastic base film 111, The plastic base film 111 needs to have the thickness which can achieve sufficient intensity | strength as a base material. Moreover, when the plastic base film 111 is thick, the flexibility of the transparent packaging material 10 or the transparent gas barrier film 11 may be insufficient. The thickness of the plastic substrate film 111 is, for example, in the range of 6 μm to 200 μm, and typically in the range of 9 μm to 100 μm.

  When manufacturing the transparent packaging material 10 or the transparent gas barrier film 11, there is no restriction | limiting in the shape of the plastic base film 111 as the material. However, when considering mass productivity, the plastic substrate film 111 is advantageously a long product.

  The primer layer 112 is a transparent layer formed on one main surface of the plastic substrate film 111. The primer layer 112 improves the adhesion between the inorganic oxide layer 113 and the plastic substrate film 111. As a result, a decrease in the adhesion between the plastic substrate film 111 and the heat-sealable resin layer 13 due to penetration of water vapor, flavor components, and the like is suppressed.

The results of positive and negative secondary ion mass spectral analysis of the primer layer 112 by a time-of-flight secondary mass ion spectrometer (TOF-SIMS) typically include aromatic carboxylic acids and polyols and their reaction product components. , The presence of an aliphatic carboxylic acid component and an isocyanate component. For example, when the positive and negative secondary ion mass spectrum analysis of the primer layer 112 by TOF-SIMS is performed, C ₇ H ₄ O ⁺ , C ₈ H ₅ O ₃ ⁺ , C ₁₀ H ₉ O ₄ ⁺ , A group of peaks derived from aromatic carboxylic acid and ethylene glycol and their reaction product components including C ₁₈ H ₁₃ O ₇ ⁺ , C ₇ H ₄ O ₂ ^— and C ₇ H ₅ O ₂ ^— , and C ₆ H ₇ O A peak group derived from an aliphatic carboxylic acid component containing ₂ ⁺ and C ₆ H ₉ O ₃ ⁺ and a peak group derived from an isocyanate containing CNO ⁻ and C ₈ H ₇ N ₂ O ⁻ are detected.

  More specifically, the primer layer 112 includes polyester urethane having an aromatic carboxylic acid group and an aliphatic carboxylic acid group. For example, the primer layer 112 is formed by applying a coating solution prepared using an aromatic carboxylic acid, an aliphatic carboxylic acid, a polyol, and an isocyanate onto a plastic substrate film 111, and heating and drying the coating film. Can be obtained.

  This coating solution is prepared by the following method, for example. First, an aromatic carboxylic acid, an aliphatic carboxylic acid, a polyol, and a solvent are mixed and a polycondensation reaction is caused to obtain a dispersion containing polyester. Next, an isocyanate is mixed into this dispersion to cause an addition reaction between the polyester and the isocyanate. Thereby, the coating liquid containing polyester urethane is obtained.

  As the aromatic carboxylic acid, aromatic polycarboxylic acid such as aromatic dicarboxylic acid can be used. As the aromatic dicarboxylic acid, for example, phthalic acid, isophthalic acid, terephthalic acid, naphthalenedicarboxylic acid, or anhydrides thereof can be used. The aromatic polycarboxylic acid may not be an aromatic dicarboxylic acid. For example, aromatic polycarboxylic acids such as trimellitic acid, pyromellitic acid, and benzenehexacarboxylic acid may be used. Aromatic polycarboxylic acids may be used alone or in combination.

  As the aliphatic carboxylic acid, an aliphatic polycarboxylic acid such as an aliphatic dicarboxylic acid can be used. Examples of the aliphatic dicarboxylic acid include maleic acid, fumaric acid, malonic acid, succinic acid, adipic acid, sebacic acid, azelaic acid, pentane-1,5-dicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, or those Anhydrides can be used. The aliphatic polycarboxylic acid may not be an aliphatic dicarboxylic acid. For example, an aliphatic tricarboxylic acid may be used. Aliphatic polycarboxylic acids may be used alone or in combination.

  Examples of the polyol include ethylene glycol, propylene glycol, 1,4-butanediol, neopentyl glycol, 1,6-hexanediol, 1,4-cyclohexanedimethanol, ethylene glycol-modified bisphenol A, glycerin, trimethylolethane, Alternatively, trimethylolpropane can be used. Polyols may be used alone or in combination.

  As isocyanate, polyisocyanate, such as diisocyanate, can be used. As the diisocyanate, for example, hexamethylene diisocyanate, isophorone diisocyanate, metaxylylene diisocyanate, tolylene diisocyanate or diphenylmethane diisocyanate can be used. Or you may use these trimethylol modified body, biuret body, or allophanate. The polyisocyanate may not be diisocyanate. For example, triisocyanate may be used. Polyisocyanate may be used alone or in combination.

  From the viewpoint of heat resistance required for the transparent packaging material 10, the softening point of the primer layer 112 may be set within a range of 70 ° C to 180 ° C. Moreover, when using a long thing as the plastic base film 111 and winding up the plastic base film 111 immediately after forming the primer layer 112, the primer layer 112 needs to be a thing which does not produce blocking. In consideration of the softening point and blocking in addition to the above-mentioned performance related to adhesion, a coating solution containing terephthalic acid and / or isophthalic acid, adipic acid, ethylene glycol, tolylene diisocyanate and / or diphenylmethane diisocyanate is used. Thus, it is advantageous to form the primer layer 112.

  The coating liquid may further contain an additive. Examples of additives include tertiary amines, imidazole derivatives, metal compounds of carboxylic acids, quaternary ammonium salts, and quaternary phosphonium salts and other curing accelerators, phenolic or phosphite antioxidants, leveling agents, Rheology modifiers, fillers, or mixtures thereof can be used.

  Although the thickness of the primer layer 112 is not limited, it is difficult to form the thin primer layer 112 as a continuous film having a uniform thickness. Further, the thick primer layer 112 has low flexibility, and may crack when the transparent gas barrier film 11 is bent. The thickness of the primer layer 112 is, for example, in the range of 10 nm to 1000 nm, and typically in the range of 20 nm to 400 nm.

  The primer layer 112 is obtained, for example, by applying a coating liquid containing the above-described components on the plastic substrate film 111 and drying the coating film. For application of the coating liquid, for example, a roll coating method, a knife edge coating method, a bar coating method, a dip coating method, a die coating method, or a gravure coating method can be used.

  Prior to application of the coating liquid, for example, in order to improve wettability and / or adhesion, a surface to be coated of the plastic substrate film 111 may be pretreated. Examples of this pretreatment include corona discharge treatment, low temperature plasma treatment, ion bombardment treatment, reactive ion etching treatment, chemical treatment, solvent treatment, or a combination thereof.

  The coating film can be dried, for example, immediately after the coating liquid is applied. Alternatively, when the plastic base film 111 is stretched, the coating liquid is applied onto the plastic base film 111 before the stretching process, and then the plastic base film 111 is stretched, and in the subsequent stress relaxation step. The coating film may be dried by heat treatment. In this case, the primer layer 112 stretched in the same direction as the plastic substrate film 111 is obtained.

  The inorganic oxide layer 113 is a gas barrier transparent layer formed on the primer layer 112 by a vapor deposition method. As a material of the inorganic oxide layer 113, for example, silicon oxide, aluminum oxide, tin oxide, magnesium oxide, or a mixture thereof can be used.

  For the formation of the inorganic oxide layer 113, for example, a vacuum evaporation method, a sputtering method, an ion plating method, or a plasma chemical vapor deposition method can be used. When the vacuum deposition method is used, for example, electron beam heating, resistance heating, or induction heating can be used for heating the evaporation material. When electron beam heating is used, the degree of freedom in selecting the evaporation material is great. When a plasma assist method or an ion beam assist method is used for vapor deposition, a denser inorganic oxide layer 113 can be formed. In addition, when reactive vapor deposition in which a gas such as oxygen is blown during vapor deposition, the inorganic oxide layer 113 having excellent transparency can be formed.

  When the inorganic oxide layer 113 is thin, it is difficult to form the inorganic oxide layer 113 as a continuous film having a uniform thickness, and sufficient gas barrier properties cannot be obtained. The thick inorganic oxide layer 113 is low in flexibility and may crack when the transparent gas barrier film 11 is bent or pulled. Further, the vapor deposition method is not suitable for forming a thick film from an economical viewpoint. The thickness of the inorganic oxide layer 113 is, for example, in the range of 1 nm to 500 nm.

  The gas barrier film 114 is a transparent layer formed on the inorganic oxide layer 113. The gas barrier coating 114 is made of a mixture containing a transparent resin and an inorganic substance such as an inorganic oxide. The inorganic oxide is, for example, silicon oxide. The gas barrier coating 114 can be omitted, but when the gas barrier coating 114 is provided, the transparent packaging material 10 having higher gas barrier properties can be obtained.

  The gas barrier coating 114 is, for example, applied on the inorganic oxide layer 113 with a coating solution containing a water-soluble polymer, one or more metal alkoxides and / or hydrolysis products thereof, and water, It is obtained by heating and drying this coating film. In addition, as a solvent of this coating liquid, water or the liquid mixture of water and alcohol can be used, for example.

  As the water-soluble polymer, for example, polyvinyl alcohol (PVA), polyvinyl pyrrolidone, starch, methyl cellulose, carboxymethyl cellulose, sodium alginate, or a mixture thereof can be used. In particular, when PVA is used, the gas barrier coating 114 having the most excellent gas barrier properties can be formed. In addition, PVA here is typically obtained by saponifying polyvinyl acetate. As this PVA, various saponified PVA can be used from partially saponified PVA in which several tens% of acetyl groups remain to fully saponified PVA in which only several% of acetyl groups remain.

A metal alkoxide is a compound represented by the general formula M (OR) _n . Here, M represents a metal such as titanium, aluminum, and zirconium or silicon, and R represents an alkyl group such as a methyl group and an ethyl group. N represents the valence of the element M.

As the metal alkoxide, for example, tetraethoxysilane [Si (OC ₂ H ₅ ) ₄ ] or triisopropoxyaluminum [Al (OCH (CH ₃ ) ₂ ) ₃ ] can be used. The hydrolysis products of tetraethoxysilane and triisopropoxyaluminum can exist relatively stably in water-containing solutions.

When alkoxysilane is used as the metal alkoxide, for example, a compound represented by Si (OR1) ₄ or R2Si (OR3) ₃ or a mixture thereof can be used as the alkoxysilane. Here, R1 and R3 represent a hydrolyzable group such as a CH ₃ group, a C ₂ H ₅ group, and a C ₂ H ₄ OCH ₃ group, and R 2 represents an organic functional group.

  In addition, since the metal oxide film obtained by hydrolyzing and condensing metal alkoxide is hard, cracks are likely to occur due to external force or strain due to volume reduction during condensation. Therefore, it is very difficult to form the metal oxide film with a uniform thickness without causing cracks.

  On the other hand, a film formed using a coating solution containing a polymer, a metal alkoxide and / or a hydrolyzate thereof, and water has higher flexibility than a metal oxide film, and thus cracks are generated. It ’s hard. However, in this film, the metal oxide is not uniformly dispersed microscopically, and a high gas barrier property may not be obtained. When a water-soluble polymer is used as this polymer, a strong hydrogen bond between the hydroxyl group of the polymer and the hydroxyl group of the hydrolyzate of the metal alkoxide is used to convert the metal oxide into the polymer during condensation. Can be uniformly dispersed. Therefore, a gas barrier property close to that of a metal oxide film can be achieved. Therefore, when such a gas barrier coating 114 is formed on the inorganic oxide layer 113, a much higher gas barrier property can be achieved as compared with the case where they are used alone.

For example, when an alkoxysilane represented by R 2 Si (OR ₃ ) ₃ is used as the metal alkoxide, it is difficult to swell even when water enters, and a gas barrier coating 114 having excellent water resistance can be obtained. In particular, when the organic functional group R2 is a water-insoluble functional group such as a vinyl group, an epoxy group, a methacryloxy group, a ureido group, and an isocyanate group, higher water resistance can be achieved.

  When the organic functional group R2 is a vinyl group or a methacryloxy group, irradiation with ionizing radiation such as ultraviolet rays or electron beams is performed in the production process.

  In addition, water and a catalyst (acid or alkali) are generally used as a reaction accelerator for hydrolysis of the metal alkoxide, but a photoacid generator may be used instead of the reaction catalyst. A photoacid generator is a compound that generates an acid upon irradiation with ionizing radiation such as ultraviolet rays, and the hydrolysis reaction of a metal alkoxide is initiated only by irradiation with ionizing radiation. Therefore, hydrolysis does not proceed in the coating solution, and there is no fear that the physical properties change with time.

  A known photocationic initiator can be used as the photoacid generator. Examples of the photocation initiator include onium salts. This onium salt is a compound that photoreacts and releases a Lewis acid.

When two types of tetraalkoxysilane represented by the general formula Si (OR1) ₄ and trialkoxysilane represented by the general formula R2Si (OR3) ₃ are used as the metal alkoxide, the ratio of these alkoxysilanes is, for example, , Si (OR1) ₄ in terms of SiO ₂ mass M ₁ and R2Si (OR3) ₃ in R2Si (OH) ₃ reduced mass M ₂ ratio of reduced mass M ₂ to the sum of M ₂ / (M ₁ + M ₂₎ is, You may set so that it may become in the range of 1% thru | or 50%. When it is smaller than 1%, the water resistance is lowered, and when it exceeds 50%, the organic functional group R2 becomes a pore of the gas barrier, and the gas barrier property is lowered.

As for the mixing ratio of the tetraalkoxysilane represented by the general formula Si (OR1) ₄ and the trialkoxysilane represented by the general formula R2Si (OR3) ₃ , the above-mentioned ratio M ₂ / (M ₁ + M ₂ ) is 5 You may set so that it may exist in the range of% thru | or 30%. In this case, the liquid content or the water-containing content can be sterilized by boiling or pressurized and heat sterilized, and water resistance and high barrier properties sufficient for long-term storage in a high temperature and high humidity environment can be achieved.

Further, when the mass of the water-soluble polymer is M ₃ , the ratio M ₁ / (M ₂ / M ₃ ) may be set in the range of 100/100 to 100/30, for example. In this case, in addition to obtaining a sufficient barrier property during long-term storage, boiling sterilization treatment, pressurization / heat sterilization treatment, etc., the gas barrier coating 5 having excellent flexibility can be obtained. Therefore, it is advantageous when used as a packaging material.

Among the alkoxysilanes represented by the general formula Si (OR1) ₄ , tetraethoxysilane can be present in a hydrolytic product relatively stably in an aqueous solvent. Therefore, when this is used, control of manufacturing conditions is relatively easy.

The alkoxysilane represented by the general formula Si (OR1) ₄ , the alkoxysilane represented by the general formula R2Si (OR3) ₃ , and the water-soluble polymer, which are components of the coating liquid that forms the gas barrier film 114, You may mix in any order. For example, an alkoxysilane represented by the general formula Si (OR1) ₄ and an alkoxysilane represented by the general formula R2Si (OR3) ₃ are separately hydrolyzed, and then these are contained in a solution containing a water-soluble polymer. May be added. This method is excellent in terms of dispersibility of silicon oxide and efficiency of hydrolysis.

  The coating liquid for forming the gas barrier film 114 can further contain an additive. As this additive, for example, an isocyanate compound, a silane coupling agent, a dispersant, a stabilizer, a rheology modifier, or a mixture thereof can be used.

  For application of the coating liquid onto the inorganic oxide layer 113, for example, a dipping method, a roll coating method, a screen printing method, a spray coating method, or a gravure printing method can be used.

  When the gas barrier coating 114 is thin, it is difficult to form the gas barrier coating 114 as a continuous film having a uniform thickness, and sufficient gas barrier properties cannot be obtained. The thick gas barrier coating 114 is likely to crack. The thickness of the gas barrier coating 114 is, for example, in the range of 0.01 μm to 50 μm.

  The adhesive layer 12 is a transparent layer that covers the inorganic oxide layer 113. Examples of the material of the adhesive layer 12 include polyurethane, polyester urethane, polyester, polyamide, epoxy resin, polyacrylic acid, polymethacrylic acid, polyethyleneimine, ethylene-acrylic acid copolymer, ethylene-methacrylic acid copolymer, Solvent-free, solvent-type, aqueous-type, or hot-melt-type adhesives containing polyvinyl acetate, polyolefin, modified polyolefin, polybutadiene, wax, casein, or a mixture thereof as a main component can be used.

For application of the adhesive onto the inorganic oxide layer 113, for example, direct gravure coating method, reverse gravure coating method, kiss coating method, die coating method, roll coating method, dip coating method, knife coating method, spray coating method, Alternatively, the Fontaen coat method or the like can be used. For example, the adhesive is applied in a dry state so that the application amount is within a range of 0.1 g / m ^{2 to} 8 g / m ² .

  The heat-sealable resin layer 13 is a transparent layer bonded to the transparent gas barrier film 11 via the adhesive layer 12. The heat-sealable resin layer 13 faces the plastic substrate film 111 with the primer layer 112, the inorganic oxide layer 113, the gas barrier film 114, and the adhesive layer 12 interposed therebetween.

  The heat sealable resin layer 13 is a transparent resin layer having heat sealability. Examples of the material of the heat-sealable resin layer 13 include polyethylene such as high-density polyethylene, medium-density polyethylene, low-density polyethylene, and linear low-density polyethylene, polypropylene, ethylene-propylene copolymer, polyester, polyamide, and ethylene. -Vinyl acetate copolymer, ethylene-vinyl acetate copolymer saponified product, polycarbonate, polyacrylonitrile, nitrocellulose, ethylene-acrylic acid copolymer, ethylene-methacrylic acid copolymer, ethylene-acrylic acid ester copolymer, Biodegradable resins such as ethylene-methacrylic acid ester copolymers, cross-linked products of these, or polylactic acid resins can be used.

  The thickness of the heat-sealable resin layer 13 is set according to the application of the transparent packaging material 10, for example. Usually, the thickness of the heat-sealable resin layer 13 is in the range of 10 μm to 200 μm.

  For bonding the heat-sealable resin layer 13 and the transparent gas barrier film 11, for example, a dry lamination method, a non-solvent lamination method, or an extrusion lamination method can be used. For example, when the extrusion laminating method is used, the adhesive layer 12 can be omitted.

  A layer other than the adhesive layer 12 may be interposed between the transparent gas barrier film 11 and the heat sealable resin layer 13. For example, a printing layer and / or a base film may be interposed between them.

  This transparent packaging material 10 can be used as at least a part of a package. For example, a bag can be formed using this transparent packaging material 10. Alternatively, the transparent packaging material 10 can be used to form a lid of a molded container. The heat-sealable resin layer 13 is positioned between the internal space of the package and the transparent gas barrier film 11.

  This transparent packaging material 10 is excellent in adhesion between the plastic substrate film 111 and the heat-sealable resin layer 13. Therefore, for example, a packaged product obtained by packaging food with the transparent packaging material 10 is less likely to cause delamination even when subjected to boiling sterilization treatment. Moreover, even if the packaged product formed by packaging the content containing the flavor component with the transparent packaging material 10 is stored for a long period of time, the adhesion between the plastic substrate film 111 and the heat-sealable resin layer 13 is maintained. Will not drop significantly. Further, a packaged product in which precision electronic components and the like are packaged with the transparent packaging material 10 is provided with the plastic substrate film 111 and the heat-sealable resin layer 13 even when left in a high temperature and high humidity environment for a long time. Adhesion does not drop significantly. Therefore, deterioration of the contents can be prevented over a long period of time.

  Thus, the transparent packaging material 10 is excellent in normal strength. Therefore, the packaged product formed by filling the four-side sealed bag formed using the transparent packaging material 10 with water as the contents is the same as the plastic base film 111 even after the boiling sterilization treatment at 95 ° C. for 30 minutes. The normal laminate strength with the heat-sealable resin layer 13 is maintained at, for example, 3.0 N / 15 mm or more.

Examples of the present invention will be described below.
<Preparation of coating liquid A>
The solvent was mixed with terephthalic acid, adipic acid and ethylene glycol to cause a polycondensation reaction. As a result, a dispersion containing a polyester resin having a number average molecular weight of about 40000 and an acid value of 10 mg KOH / g was obtained. Next, isophorone diisocyanate was added to this dispersion to cause an addition reaction between the polyester resin and the isocyanate. This addition reaction was continued until the absorption peak of the isocyanate group disappeared from the infrared absorption spectrum. As described above, a coating liquid containing a polyester urethane resin having an acid value of 3 mg KOH / g and a softening point of 70 ° C. was obtained. Hereinafter, this coating solution is referred to as “coating solution A”.

<Preparation of coating solution B>
Isophthalic acid, adipic acid and ethylene glycol were mixed in a solvent to cause a polycondensation reaction. As a result, a dispersion containing a polyester resin having a number average molecular weight of about 40,000 and an acid value of 20 mg KOH / g was obtained. Next, tolylene diisocyanate and diphenylmethane diisocyanate were added to this dispersion to cause an addition reaction between the polyester resin and the isocyanate. This addition reaction was continued until the absorption peak of the isocyanate group disappeared from the infrared absorption spectrum. As described above, a coating liquid containing a polyester urethane resin having an acid value of 15 mg KOH / g and a softening point of 90 ° C. was obtained. Hereinafter, this coating solution is referred to as “coating solution B”.

<Preparation of coating liquid C>
Isophthalic acid, sebacic acid, ethylene glycol, and neopentyl glycol were mixed in a solvent to cause a polycondensation reaction. As a result, a dispersion containing a polyester resin having a number average molecular weight of about 20,000 and an acid value of 50 mg KOH / g was obtained. Next, isophorone diisocyanate was added to this dispersion to cause an addition reaction with the polyester resin. This addition reaction was continued until the absorption peak of the isocyanate group disappeared from the infrared absorption spectrum. As described above, a coating liquid containing a polyester urethane resin having an acid value of 6 mg KOH / g and a softening point of 100 ° C. was obtained. Hereinafter, this coating solution is referred to as “coating solution C”.

<Preparation of coating solution D>
Isophthalic acid, azelaic acid, ethylene glycol, and 1,6-hexanediol were mixed in a solvent to cause a polycondensation reaction. As a result, a dispersion containing a polyester resin having a number average molecular weight of about 10,000 and an acid value of 100 mg KOH / g was obtained. Next, tolylene diisocyanate and diphenylmethane diisocyanate were added to this dispersion to cause an addition reaction with the polyester resin. This addition reaction was continued until the absorption peak of the isocyanate group disappeared from the infrared absorption spectrum. As described above, a coating liquid containing a polyester urethane resin having an acid value of 20 mg KOH / g and a softening point of 83 ° C. was obtained. Hereinafter, this coating solution is referred to as “coating solution D”.

<Preparation of coating solution E>
Isophthalic acid, terephthalic acid, ethylene glycol, and 1,4-butanediol were mixed in a solvent to cause a polycondensation reaction. As a result, a dispersion containing a polyester resin having a number average molecular weight of about 40000 and an acid value of 50 mg KOH / g was obtained. Next, tolylene diisocyanate and diphenylmethane diisocyanate were added to this dispersion to cause an addition reaction with the polyester resin. This addition reaction was continued until the absorption peak of the isocyanate group disappeared from the infrared absorption spectrum. As described above, a coating liquid containing a polyester urethane resin having an acid value of 20 mg KOH / g and a softening point of 83 ° C. was obtained. Hereinafter, this coating solution is referred to as “coating solution E”.

<Preparation of coating solution F>
Isophthalic acid, azelaic acid, ethylene glycol, and 1,6-hexanediol were mixed in a solvent to cause a polycondensation reaction. As described above, a coating solution containing a polyester resin having an acid value of 100 mg KOH / g and a softening point of 75 ° C. was obtained. Hereinafter, this coating liquid is referred to as “coating liquid F”.
Table 1 below summarizes the materials used for the preparation of coating solutions A to F.

<Preparation of coating solution G>
89 g of 0.1N hydrochloric acid aqueous solution was mixed with 10 g of tetraethoxysilane, and this mixed solution was stirred for 30 minutes to cause hydrolysis of tetraethoxysilane. This gave a solution with a solids content of 3% by weight in terms of SiO _2. Next, a solution containing 3% by mass of polyvinyl alcohol was added. As a solvent for polyvinyl alcohol, a mixed solution containing water and isopropyl alcohol at a mass ratio of 90:10 was used. Hereinafter, the coating liquid thus obtained is referred to as “coating liquid G”.

<Preparation of coating solution H>
17.9 g of tetraethoxysilane, 10 g of methanol, and 72.1 g of 0.1N hydrochloric acid aqueous solution were mixed and stirred for 30 minutes to hydrolyze tetraethoxysilane. Thus, to obtain a hydrolysis solution containing solids 5% by weight in terms of SiO _2. Hereinafter, this hydrolysis solution is referred to as “solution 1”.

  PVA was dissolved in a mixed solvent containing water and isopropyl alcohol at a mass ratio of 95: 5, and an aqueous PVA solution was prepared so that the solid content concentration was 5% by mass. Hereinafter, this PVA aqueous solution is referred to as “Solution 2”.

A 1N aqueous hydrochloric acid solution was added to an isopropyl alcohol solution of γ-glycidoxypropyltrimethoxysilane. At this time, the mass ratio of water to isopropyl alcohol was 50:50. The concentration of γ-glycidoxypropyltrimethoxysilane in this mixed solution was 5% by mass in terms of R2Si (OH) ₃ . Next, this mixed solution was stirred for 20 minutes to hydrolyze γ-glycidoxypropyltrimethoxysilane. This obtained the hydrolysis solution containing 5 mass% solid content in conversion of R2Si (OH) ₃ . Hereinafter, this hydrolysis solution is referred to as “solution 3”.

  Then, the solution 1, the solution 2, and the solution 3 were mixed so that mass ratio of those solid content might be set to 60:30:10. Hereinafter, this mixed solution is referred to as “coating liquid H”.

<Preparation of coating liquid I>
Water was gradually added to an isopropyl alcohol solution of 3-aminopropyltrimethoxysilane and stirred for 30 minutes to hydrolyze 3-aminopropyltrimethoxysilane. The concentration of 3-aminotrimethoxysilane was 5% by mass in terms of R2Si (OH) ₃ . This obtained the hydrolysis solution containing 5 mass% solid content in conversion of R2Si (OH) ₃ . Hereinafter, this hydrolysis solution is referred to as “solution 4”.

  Then, the solution 1, the solution 2, and the solution 4 were mixed so that the mass ratio of those solid content concentrations might be 60:25:15. Hereinafter, this liquid mixture is referred to as “coating liquid I”.

<Preparation of coating liquid J>
Solution 1, solution 2 and solution 3 were mixed so that the mass ratio of their solids was 30:20:60. Hereinafter, this liquid mixture is referred to as “coating liquid J”.

<Preparation of coating liquid K>
Solution 1, solution 2, and solution 3 were mixed so that the mass ratio of their solid contents was 80:10:10. Hereinafter, this liquid mixture is referred to as “coating liquid K”.

<Manufacture of transparent gas barrier film A1 and transparent packaging material A1>
First, a plastic substrate film made of nylon 6 and having a thickness of 150 μm was prepared.

  Next, the coating liquid A was applied to one main surface of the plastic substrate film by a roll coating method. Subsequently, the plastic substrate film was stretched at the same stretch ratio in the longitudinal direction and the transverse direction until the thickness became 15 μm, and the coating film was dried. In this way, a primer layer having a thickness of 40 nm was formed on the plastic substrate film.

  Next, an inorganic oxide layer made of aluminum oxide and having a thickness of 10 nm was formed on the primer layer using a vacuum vapor deposition apparatus utilizing an electron beam heating method.

  Then, the coating liquid G was apply | coated on the inorganic oxide layer by the gravure coating method. Subsequently, the coating film was dried, thereby obtaining a gas barrier coating film having a thickness of 0.5 μm.

  As described above, a transparent gas barrier film was completed. Hereinafter, this transparent gas barrier film is referred to as “transparent gas barrier film A1”.

  Next, the transparent gas barrier film A1 and the heat sealable resin layer were bonded together by a dry lamination method so that the heat sealable resin layer faced the gas barrier film. As the heat-sealable resin layer, a 50 μm-thick linear low-density polyethylene film (manufactured by Tosero Co., Ltd., TUX-FCS) is used, and as an adhesive, an adhesive for polyurethane-based laminate (manufactured by Mitsui Chemicals Polyurethane Co., Ltd.) , A616 / A65).

  Thereafter, this laminate was cured at 40 ° C. for 5 days. The transparent packaging material was completed as mentioned above. Hereinafter, this transparent packaging material is referred to as “transparent packaging material A1”.

<Manufacture of transparent gas barrier film A2 and transparent packaging material A2>
Except that an inorganic oxide layer made of silicon oxide having a thickness of 40 nm was formed instead of an inorganic oxide layer made of aluminum oxide having a thickness of 10 nm, the same method as described for the transparent gas barrier film A1 was used. A transparent gas barrier film was produced. Hereinafter, this transparent gas barrier film is referred to as “transparent gas barrier film A2”.

  Next, a transparent packaging material was produced by the same method as described for the transparent packaging material A1 except that the transparent gas barrier film A2 was used instead of the transparent gas barrier film A1. Hereinafter, this transparent packaging material is referred to as “transparent packaging material A2”.

<Manufacture of transparent gas barrier film A3 and transparent packaging material A3>
Except that an inorganic oxide layer made of magnesium oxide having a thickness of 20 nm was formed instead of an inorganic oxide layer made of aluminum oxide having a thickness of 10 nm, the same method as described for the transparent gas barrier film A1 was used. A transparent gas barrier film was produced. Hereinafter, this transparent gas barrier film is referred to as “transparent gas barrier film A3”.

  Next, a transparent packaging material was produced by the same method as described for the transparent packaging material A1 except that the transparent gas barrier film A3 was used instead of the transparent gas barrier film A1. Hereinafter, this transparent packaging material is referred to as “transparent packaging material A3”.

<Manufacture of transparent gas barrier film B1 and transparent packaging material B1>
A transparent gas barrier film was produced by the same method as described for the transparent gas barrier film A1 except that the coating liquid B was used instead of the coating liquid A. Hereinafter, this transparent gas barrier film is referred to as “transparent gas barrier film B1”.

  Next, a transparent packaging material was produced by the same method as described for the transparent packaging material A1 except that the transparent gas barrier film B1 was used instead of the transparent gas barrier film A1. Hereinafter, this transparent packaging material is referred to as “transparent packaging material B1”.

<Manufacture of transparent gas barrier film B2 and transparent packaging material B2>
First, a plastic substrate film having a thickness of 150 μm made of polyethylene terephthalate was prepared.

  Next, the plastic substrate film was stretched in the longitudinal direction. Subsequently, the coating liquid B was apply | coated by roll coating method on one main surface of this plastic substrate film. Subsequently, the plastic substrate film was stretched in the transverse direction and the coating film was dried. In addition, the draw ratio of the vertical direction and the draw ratio of the horizontal direction were made equal, and these drawing were performed so that the thickness of the plastic substrate film was 12 μm. In this way, a primer layer having a thickness of 50 nm was formed on the plastic substrate film.

  Thereafter, an inorganic oxide layer and a gas barrier film were sequentially formed on the primer layer by the same method as described for the transparent gas barrier film A1.

  As described above, a transparent gas barrier film was completed. Hereinafter, this transparent gas barrier film is referred to as “transparent gas barrier film B2”.

  Next, a transparent packaging material was produced by the same method as described for the transparent packaging material A1 except that the transparent gas barrier film B2 was used instead of the transparent gas barrier film A1. Hereinafter, this transparent packaging material is referred to as “transparent packaging material B2”.

<Manufacture of transparent gas barrier film B3 and transparent packaging material B3>
By the same method as described for the transparent gas barrier film B2 except that an inorganic oxide layer made of silicon oxide was formed in place of the inorganic oxide layer made of aluminum oxide and having a thickness of 50 nm instead of aluminum oxide. A transparent gas barrier film was produced. Hereinafter, this transparent gas barrier film is referred to as “transparent gas barrier film B3”.

  Next, a transparent packaging material was produced by the same method as described for the transparent packaging material A1 except that the transparent gas barrier film B3 was used instead of the transparent gas barrier film A1. Hereinafter, this transparent packaging material is referred to as “transparent packaging material B3”.

<Manufacture of transparent gas barrier film B4 and transparent packaging material B4>
First, a plastic base film having a thickness of 150 μm made of polypropylene was prepared.

  Next, this plastic base film was stretched at the same stretch ratio in the longitudinal direction and the lateral direction until the thickness became 20 μm. Subsequently, the coating liquid B was apply | coated by roll coating method on one main surface of this plastic substrate film. Subsequently, this coating film was dried. In this way, a primer layer having a thickness of 100 nm was formed on the plastic substrate film.

  Thereafter, an inorganic oxide layer and a gas barrier film were sequentially formed on the primer layer by the same method as described for the transparent gas barrier film A1.

  As described above, a transparent gas barrier film was completed. Hereinafter, this transparent gas barrier film is referred to as “transparent gas barrier film B4”.

  Next, a transparent packaging material was produced by the same method as described for the transparent packaging material A1 except that the transparent gas barrier film B4 was used instead of the transparent gas barrier film A1. Hereinafter, this transparent packaging material is referred to as “transparent packaging material B4”.

<Manufacture of transparent gas barrier film C and transparent packaging material C>
A transparent gas barrier film was produced in the same manner as described for the transparent gas barrier film A1 except that the coating liquid C was used instead of the coating liquid A. Hereinafter, this transparent gas barrier film is referred to as “transparent gas barrier film C”.

  Next, a transparent packaging material was produced by the same method as described for the transparent packaging material A1 except that the transparent gas barrier film C was used instead of the transparent gas barrier film A1. Hereinafter, this transparent packaging material is referred to as “transparent packaging material C”.

<Manufacture of transparent gas barrier film D and transparent packaging material D>
A transparent gas barrier film was produced in the same manner as described for the transparent gas barrier film A1 except that the coating liquid D was used instead of the coating liquid A. Hereinafter, this transparent gas barrier film is referred to as “transparent gas barrier film D”.

  Next, a transparent packaging material was produced by the same method as described for the transparent packaging material A1 except that the transparent gas barrier film D was used instead of the transparent gas barrier film A1. Hereinafter, this transparent packaging material is referred to as “transparent packaging material D”.

<Manufacture of transparent gas barrier film E1 and transparent packaging material E1>
A transparent gas barrier film was produced in the same manner as described for the transparent gas barrier film B3 except that the coating liquid E was used instead of the coating liquid B. Hereinafter, this transparent gas barrier film is referred to as “transparent gas barrier film E1”.

  Next, a transparent packaging material was produced by the same method as described for the transparent packaging material A1 except that the transparent gas barrier film E1 was used instead of the transparent gas barrier film A1. Hereinafter, this transparent packaging material is referred to as “transparent packaging material E1”.

<Manufacture of transparent gas barrier film E2 and transparent packaging material E2>
A transparent gas barrier film was produced by the same method as described for the transparent gas barrier film E1 except that the coating liquid H was used in place of the coating liquid G when the gas barrier film was obtained. Hereinafter, this transparent gas barrier film is referred to as “transparent gas barrier film E2”.

  Next, a transparent packaging material was produced by the same method as described for the transparent packaging material A1 except that the transparent gas barrier film E2 was used instead of the transparent gas barrier film A1. Hereinafter, this transparent packaging material is referred to as “transparent packaging material E2.”

<Manufacture of transparent gas barrier film E3 and transparent packaging material E3>
Transparent gas barrier film E1 except that instead of forming a gas barrier film having a thickness of 0.5 μm using coating liquid G, a gas barrier film having a thickness of 5.0 μm was formed using coating liquid H A transparent gas barrier film was produced in the same manner as described above. Hereinafter, this transparent gas barrier film is referred to as “transparent gas barrier film E3”.

  Next, a transparent packaging material was produced by the same method as described for the transparent packaging material A1 except that the transparent gas barrier film E3 was used instead of the transparent gas barrier film A1. Hereinafter, this transparent packaging material is referred to as “transparent packaging material E3”.

<Manufacture of transparent gas barrier film E4 and transparent packaging material E4>
A transparent gas barrier film E1 except that instead of forming a gas barrier film having a thickness of 0.5 μm using the coating liquid G, a gas barrier film having a thickness of 1.0 μm was formed using the coating liquid I. A transparent gas barrier film was produced in the same manner as described above. Hereinafter, this transparent gas barrier film is referred to as “transparent gas barrier film E4”.

  Next, a transparent packaging material was produced by the same method as described for the transparent packaging material A1 except that the transparent gas barrier film E4 was used instead of the transparent gas barrier film A1. Hereinafter, this transparent packaging material is referred to as “transparent packaging material E4”.

<Manufacture of transparent gas barrier film E5 and transparent packaging material E5>
A transparent gas barrier film was produced by the same method as described for the transparent gas barrier film E1 except that the coating liquid J was used instead of the coating liquid G. Hereinafter, this transparent gas barrier film is referred to as “transparent gas barrier film E5”.

  Next, a transparent packaging material was produced by the same method as described for the transparent packaging material A1 except that the transparent gas barrier film E5 was used instead of the transparent gas barrier film A1. Hereinafter, this transparent packaging material is referred to as “transparent packaging material E5”.

<Manufacture of transparent gas barrier film E6 and transparent packaging material E6>
A gas barrier film is formed using the coating liquid K instead of the coating liquid G, and an inorganic oxide layer made of aluminum oxide is formed with a thickness of 10 nm instead of an inorganic oxide layer made of silicon oxide with a thickness of 50 nm. A transparent gas barrier film was produced by the same method as that described for the transparent gas barrier film E1 except that. Hereinafter, this transparent gas barrier film is referred to as “transparent gas barrier film E6”.

  Next, a transparent packaging material was produced by the same method as described for the transparent packaging material A1 except that the transparent gas barrier film E6 was used instead of the transparent gas barrier film A1. Hereinafter, this transparent packaging material is referred to as “transparent packaging material E6”.

<Manufacture of transparent gas barrier film F and transparent packaging material F>
A transparent gas barrier film was produced in the same manner as described for the transparent gas barrier film A1 except that the coating liquid F was used instead of the coating liquid A. Hereinafter, this transparent gas barrier film is referred to as “transparent gas barrier film F”.

  Next, a transparent packaging material was produced by the same method as described for the transparent packaging material A1 except that the transparent gas barrier film F was used instead of the transparent gas barrier film A1. Hereinafter, this transparent packaging material is referred to as “transparent packaging material F”.

<Manufacture of transparent gas barrier film X and transparent packaging material X>
A transparent gas barrier film was produced by the same method as described for the transparent gas barrier film A1 except that the primer layer was not formed. Hereinafter, this transparent gas barrier film is referred to as “transparent gas barrier film X”.

  Next, a transparent packaging material was produced by the same method as described for the transparent packaging material A1 except that the transparent gas barrier film X was used instead of the transparent gas barrier film A1. Hereinafter, this transparent packaging material is referred to as “transparent packaging material X”.

Tables 2 and 3 below summarize the configurations of the transparent gas barrier films A1 to A3, B1 to B4, C, D, E1 to E6, F, and X. In Tables 2 and 3, “NY6” indicates nylon 6, “PET” indicates polyethylene terephthalate, and “PP” indicates polypropylene. “Film formation → longitudinal and transverse stretching” indicates that the base film was stretched in the longitudinal and lateral directions after the coating film of the primer layer was formed. “Longitudinal stretching → deposition → transverse stretching” indicates that the base film was stretched in the longitudinal direction, then a coating film of the primer layer was formed, and then the base film was stretched in the lateral direction. “Longitudinal and transverse stretching → film formation” indicates that the primer film was formed after stretching the base film in the longitudinal and transverse directions.

<TOF-SIMS analysis of primer layer>
The primer layers of the transparent gas barrier films A1 to A3, B1 to B4, C, D, E1 to E6, and F were analyzed by TOF-SIMS. As the TOF-SIMS analyzer, TRIFT2 manufactured by ULVAC-PHI is used, and the primary ion is ⁶⁹ Ga ⁺ , the primary ion acceleration voltage is 15 kV, the measurement area is 100 μm square, and the charge correction electron gun is used. The ion species detected from the primer layer were analyzed by secondary ion mass spectrum.

  Each of the primer layers of the transparent gas barrier films A1 to A3, B1 to B4, C, D, and E1 to E6 includes an aromatic carboxylic acid and a polyol, a reaction product component thereof, an aliphatic carboxylic acid component, and an isocyanate. It was judged that it contained an ingredient. On the other hand, the transparent gas barrier film F was judged to contain an aromatic carboxylic acid and a polyol, a reaction product component thereof, and an aliphatic carboxylic acid component, and an isocyanate component was not detected.

  The primary gas layers of the transparent gas barrier films A1 to A3, B1 to B4, C, D, E1 to E6, and F were confirmed from the positive and negative secondary ion mass spectrum analysis results by TOF-SIMS. The peaks were as follows.

(1) Peak groups derived from aromatic carboxylic acid and ethylene glycol and their reaction product components: C ₇ H ₄ O ⁺ , C ₈ H ₅ O ₃ ⁺ , C ₁₀ H ₉ O ₄ ⁺ , C ₁₈ H ₁₃ O ^{_{7 +, C 7 H 4 O}} 2 - and C ₇ H ₅ O ₂ ^-
(2) Peak group derived from aliphatic carboxylic acid component: C ₆ H ₇ O ₂ ⁺ and C ₆ H ₉ O ₃ ⁺
(3) an isocyanate-derived peaks: CNO ^- and C ₈ H ₇ N ₂ O ^-
<Measurement of oxygen permeability>
Each of transparent gas barrier films A1 to A3, B1 to B4, C, D, E1 to E6, F and X is defined in Japanese Industrial Standards JIS K7126-1987 “Plastic Film and Sheet Gas Permeability Test Method”. The oxygen permeability was measured according to the B method (isobaric method). This measurement was performed using an Oxford 2/21 manufactured by Modern Control in an environment where the temperature was 30 ° C. and the relative humidity was 70%. Tables 4 and 5 below summarize the measurement results.

<Measurement of initial laminate strength>
For each of transparent packaging materials A1 to A3, B1 to B4, C, D, E1 to E6, F and X, Japanese Industrial Standard JIS K6854-3: 1999 “Adhesive—Peeling Adhesive Strength Test Method—Part 3: The laminate strength was measured according to the test method specified in “T-peeling”.

  That is, first, a strip-shaped test piece having a width of 15 mm was prepared from each of the transparent packaging materials A1 to A3, B1 to B4, C, D, E1 to E6, F, and X. Next, the heat-sealable resin layer and the transparent gas barrier film were peeled from each other at one end of each test piece, and each was attached to a gripping tool of a tensile tester. Thereafter, a tensile stress was applied to separate the heat-sealable resin layer and the transparent gas barrier film from each other, and the relationship between the peeling length (grasping movement distance) and the tensile stress was recorded. Here, the peeling speed was 300 mm / min. And average peeling force (N) was calculated | required from the force-grasping movement distance curve over the peeling length of 100 mm or more except the first and the last 25 mm. This average peel force (N) was taken as the laminate strength.

  Tables 4 and 5 below summarize the measurement results. In addition, the "break" in Table 4 and Table 5 means that the break occurred before the heat-sealable resin layer and the transparent gas barrier film peeled from each other.

<Measurement of laminate strength after boiling treatment>
Using each of the transparent packaging materials A1 to A3, B1 to B4, C, D, E1 to E6, F and X, a four-side sealed bag having a size of 100 mm × 150 mm was prepared. Each four-sided seal bag was filled with 150 g of water. Next, these packaged products were subjected to boiling treatment at 95 ° C. for 30 minutes, and then the laminate strength was measured by the same method as described above. Tables 4 and 5 below summarize the measurement results.

<Drop test>
Ten transparent packaging materials having dimensions of 100 mm × 150 mm were prepared using transparent packaging materials A1 to A3, B1 to B4, C, D, E1 to E6, F and X, respectively. Each four-sided seal bag was filled with 150 g of water. Next, each of these packages was dropped 100 times from a height of 1.5 m. And the number of bags torn by this drop test was calculated | required about each of transparent packaging material A1 thru | or A3, B1 thru | or B4, C, D, E1 to E6, F, and X. Tables 4 and 5 below summarize the test results.

<Measurement of laminate strength after storage of vinegar>
Using each of the transparent packaging materials A1 to A3, B1 to B4, C, D, E1 to E6, F and X, a four-side sealed bag having a size of 100 mm × 100 mm was prepared. Each four-sided seal bag was filled with 20 g of vinegar. Next, each of these packaged products was left in an environment of 40 ° C. for one month, and then the laminate strength was measured by the same method as described above.

Tables 4 and 5 below summarize the measurement results. Note that “delamination” in Tables 4 and 5 indicates that delamination occurred before the measurement of the laminate strength.

  As shown in Tables 4 and 5, the transparent gas barrier films A1 to A3, B1 to B4, C, D, E1 to E6, F and X all have sufficiently low oxygen permeability. In addition, the transparent packaging materials A1 to A3, B1 to B4, C, D, and E1 to E6 have sufficiently high laminate strength both after boiling and after storage of vinegar. The results of the drop test also indicate that the transparent packaging materials A1 to A3, B1 to B4, C, D, and E1 to E6 have excellent performance. From the above, the transparent packaging materials A1 to A3, B1 to B4, C, D, and E1 to E6 are, for example, packaging bodies that require boiling sterilization treatment, packaging bodies that contain contents containing flavor components, and the like. It can be seen that it is particularly suitable for the application.

Sectional drawing which shows schematically the transparent packaging material which concerns on 1 aspect of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Transparent packaging material, 11 ... Transparent gas barrier film, 12 ... Adhesive layer, 13 ... Heat-sealable resin layer, 111 ... Plastic base film, 112 ... Primer layer, 113 ... Inorganic oxide layer, 114 ... Gas barrier property Coating.

Claims (13)

A plastic substrate film;
A primer layer formed on one main surface of the base film and including a polyester urethane having an aromatic carboxylic acid group and an aliphatic carboxylic acid group;
A transparent gas barrier film comprising an inorganic oxide layer formed on the primer layer by a vapor deposition method.   The results of the positive and negative secondary ion mass spectrum analysis of the primer layer by a time-of-flight secondary ion mass spectrometer are as follows: aromatic carboxylic acid and polyol, their reaction product component, aliphatic carboxylic acid component, isocyanate The gas barrier film according to claim 1, which exhibits the presence of components. C ₇ H ₄ O ⁺ , C ₈ H ₅ O ₃ ⁺ , C ₁₀ H ₉ O were analyzed when positive and negative secondary ion mass spectrum analysis was performed on the primer layer using a time-of-flight secondary ion mass spectrometer. ^{_{4 +, C 18 H 13 O}} 7 +, C 7 H 4 O 2 - and C ₇ H ₅ O ₂ ^- and peaks derived from aromatic carboxylic acid and ethylene glycol and the reaction product thereof component containing, C ₆ A peak group derived from an aliphatic carboxylic acid component containing H ₇ O ₂ ⁺ and C ₆ H ₉ O ₃ ⁺ and a peak group derived from an isocyanate containing CNO ⁻ and C ₈ H ₇ N ₂ O ⁻ are detected. The gas barrier film according to claim 1 or 2.   The polyester urethane is a polyester obtained by a polycondensation reaction between an aromatic carboxylic acid containing terephthalic acid and / or isophthalic acid, an aliphatic carboxylic acid containing adipic acid and a polyol containing ethylene glycol, and tolylene diisocyanate and / or diphenylmethane. The gas barrier film according to any one of claims 1 to 3, comprising a polyester urethane obtained by an addition reaction with an isocyanate containing a diisocyanate. The gas barrier film according to any one of claims 1 to 4, wherein the base film is a stretched film containing one selected from the group consisting of polyester, polyamide, and polypropylene.   The gas barrier film according to claim 1, wherein the base film and the primer layer are stretched in the same direction.   7. The gas barrier film according to claim 1, wherein the inorganic oxide layer contains at least one selected from the group consisting of aluminum oxide, silicon oxide, and magnesium oxide.   8. The gas barrier film according to claim 1, further comprising a gas barrier film formed on the inorganic oxide layer and made of a mixture containing a transparent resin and an inorganic material. 9.   The gas barrier film according to claim 8, wherein the gas barrier film is made of a solution containing a water-soluble polymer, a metal alkoxide and / or a hydrolysis product thereof, and water.   The gas barrier film according to claim 8, wherein the gas barrier film is made of a solution containing a water-soluble polymer, two or more metal alkoxides and / or hydrolysis products thereof, and water. .   The gas barrier film according to claim 8, wherein the metal alkoxide or the hydrolysis product thereof contained in the gas barrier film is a tetraalkoxysilane and a trialkoxysilane or a hydrolysis product thereof.   The gas barrier film according to any one of claims 1 to 11, and a heat-sealable resin layer bonded to the gas barrier film and facing the plastic substrate film with the inorganic oxide layer interposed therebetween. A transparent packaging material characterized by comprising:   A package comprising the packaging material according to claim 12.

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