JP2010149300A - Gas barrier film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a gas barrier film of excellent gas barrier property including at least a composite layer, in which an easily bondable layer, an anchor coating layer, and a vapor deposition layer of an inorganic oxide are sequentially laminated, on at least one face of a polyamide resin film base material. <P>SOLUTION: This gas barrier film includes at least the composite layer laminated sequentially with the easily bondable layer 112, the anchor coating layer 113, the vapor deposition layer 114 of the inorganic oxide, on at least one face of the polyamide resin film base material 111, and the composite layer has 5 nm or less of surface roughness Rz (10 point average roughness) on a surface, and has 101,000 nm<SP>2</SP>or less of surface area per 1 μm square. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention provides a gas barrier property in which at least one composite layer in which an easy-adhesion layer, an anchor coat layer, and an inorganic oxide vapor-deposited thin film layer are sequentially laminated is provided on at least one surface of a polyamide-based resin film substrate. The present invention relates to a gas barrier film having excellent resistance.

  For packaging foods, pharmaceuticals, precision electronic parts, etc., a packaging material having excellent gas barrier properties may be used. For example, when a food is packaged with a high gas barrier packaging material, it is possible to suppress the alteration of proteins, oils and the like contained in the food, and maintain the flavor and freshness over a long period of time. 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, and when an electronic component is packaged with a high gas barrier packaging material, metal corrosion or insulation failure occurs. Etc. can be prevented.

  The high gas barrier packaging material used in this way generally has a multilayer structure in which a gas barrier layer is laminated on a part thereof. This gas barrier layer is made of, for example, a metal such as aluminum, polyvinylidene chloride (PVDC), saponified ethylene-vinyl alcohol copolymer (EVOH), or nylon which is a polyamide obtained by polycondensation reaction of metaxylenediamine and adipic acid. It consists of MXD6 etc. Although the high gas barrier packaging material provided with such a gas barrier layer exhibits a relatively high gas barrier property, it has some drawbacks.

  For example, a high gas barrier packaging material in which a metal foil is laminated as a gas barrier layer exhibits excellent gas barrier properties regardless of environmental changes such as temperature and humidity. However, the package made using this packaging material cannot visually recognize the contents, and must be treated as non-combustible when disposing of it. There are various drawbacks, such as the inability to use a metal detector. Moreover, the packaged product in which the contents are packaged with this package is not suitable for the microwave heat treatment.

  Moreover, the high gas barrier packaging material having a PVDC layer is inexpensive and has a relatively high gas barrier property, but there is a concern that harmful gases are generated when incinerated.

  Further, the high gas barrier packaging material having the EVOH layer or the nylon MXD6 layer has a large environmental dependency of the gas barrier property. In particular, there is a disadvantage that the gas barrier property is significantly deteriorated under a high temperature and high humidity environment.

  Corresponding to this situation, in Patent Documents 1 and 2, vapor-deposited thin films of inorganic oxides such as silicon oxide, aluminum oxide, and magnesium oxide are formed on a plastic film substrate by a vapor deposition method such as vacuum vapor deposition or sputtering. A gas barrier film formed by forming a layer has been proposed. This gas barrier film has transparency and excellent gas barrier properties. Therefore, this gas barrier film is suitable as a high gas barrier packaging material.

  However, such a transparent vapor deposition film having excellent gas barrier properties also has the following problems.

That is, the deposited thin film of silicon oxide is required to have a thick film thickness in order to ensure high gas barrier properties, moisture resistance, etc., but if the film thickness is increased, curling is likely to occur, and handling properties will be poor. When handled roughly, there is a problem that cracks are generated in the deposited thin film, and gas barrier properties, moisture resistance, etc. are lowered. There is also a problem that the deposited thin film is colored. In addition, an aluminum oxide vapor-deposited thin film can exhibit a certain level of gas barrier properties and moisture-proof properties when compared with a silicon oxide vapor-deposited thin film. However, when the film thickness is reduced, stable gas barrier properties and moisture-proof properties are exhibited. There is a problem that you can not. In addition, if the film thickness is increased in order to develop gas barrier properties, the deposited thin film is also colored.

In order to solve the above problems and provide a film having excellent gas barrier properties, for example, Patent Document 3 mentions a method of smoothing the surface of the vapor-deposited thin film layer, the surface roughness (Rms) and the particle size of the vapor-deposited layer. It stipulates. In Patent Document 4, the same method is cited and the center plane average roughness (SRa) and the number of peaks (SPc) are defined. Furthermore, in patent document 5, the surface roughness of a film base material is specified. However, none of the methods has provided a sufficient gas barrier property, and a transparent and high gas barrier film cannot be provided.
U.S. Pat. No. 3,442,686 JP 49-041469 A Patent No. 3675904 Japanese Patent Laid-Open No. 11-320794 JP 2003-300270 A

  The subject of the present invention made in order to solve the above-mentioned problems is that at least one surface of the polyamide-based resin film substrate has an easy-adhesion layer, an anchor coat layer, and an inorganic oxide vapor-deposited thin film layer. It is an object of the present invention to provide a gas barrier film which is provided with at least a composite layer formed by sequentially laminating layers so that excellent gas barrier properties can be exhibited even if the thickness of a deposited thin film layer is thin.

In order to achieve the above object, the invention according to claim 1 is such that an easy-adhesion layer, an anchor coat layer, and an inorganic oxide vapor-deposited thin film layer are sequentially laminated on at least one surface of a polyamide-based resin film substrate. The composite layer is at least provided, the surface roughness Rz (ten-point average roughness) of the surface of the composite layer is 5 nm or less, and the surface area per 1 μm square is 101000 nm ² or less. It is a gas barrier film characterized.

  The invention according to claim 2 is the gas barrier film according to claim 1, wherein the easy-adhesion layer contains nitrogen atoms, adipic acid, and bisphenol glycidyl ether.

  Furthermore, the invention according to claim 3 is the gas barrier film according to claim 1 or 2, wherein the anchor coat layer is a reaction product of an acrylic polyol, an isocyanate compound and a metal alkoxide or a hydrolysis product thereof. It is characterized by including.

  Furthermore, the invention according to claim 4 is the gas barrier film according to any one of claims 1 to 3, wherein the inorganic oxide is any one of aluminum oxide, silicon oxide, magnesium oxide, or a mixture thereof. It is characterized by being.

Furthermore, the invention according to claim 5 is the gas barrier film according to any one of claims 1 to 4, wherein water and a water-soluble high film are formed on the inorganic oxide vapor-deposited thin film layer of the composite layer. A gas barrier coating layer, which is a dry film of a thin film made of a coating solution containing molecules, a metal alkoxide, a hydrolysis product thereof, and at least one compound selected from the group consisting of tin chloride, is provided. It is characterized by.

  Furthermore, the invention according to claim 6 is the gas barrier film according to any one of claims 1 to 4, wherein a water-soluble polymer and an inorganic oxide vapor-deposited thin film layer of the composite layer are formed on the gas barrier film. A gas barrier coating layer which is a dry film of a thin film made of a coating liquid containing tetraalkoxysilane or a hydrolysis product thereof and trialkoxysilane or a hydrolysis product thereof is provided.

  Furthermore, in the invention according to claim 7, in the gas barrier film according to claim 6, the organic functional group other than the alkoxy group bonded to silicon of the trialkoxysilane of the coating solution is a hydrophobic organic functional group. It is characterized by that.

  The gas barrier film of the present invention is an inorganic oxide of a composite layer in which an easy-adhesion layer, an anchor coat layer, and an inorganic oxide vapor-deposited thin film layer are sequentially laminated on at least one surface of a polyamide-based resin film substrate. Since the vapor-deposited thin film layer is provided in a state of good adhesion, excellent gas barrier properties can be exhibited even if the vapor-deposited thin film layer is thin.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

  FIG. 1 shows a schematic cross-sectional configuration of a gas barrier film according to an embodiment of the present invention.

  The gas barrier film 11 basically has an easy adhesion layer 112, an anchor coat layer 113, and an inorganic oxide vapor-deposited thin film layer 114 sequentially laminated on at least one surface of a polyamide-based resin film substrate 111. The composite layer is provided at least. FIG. 1 shows an example in which a gas barrier coating layer is further laminated on the composite layer having the above structure. 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 polyamide-based resin film substrate 111 is a film-shaped substrate made of a polyamide-based resin such as homopolyamide, copolyamide, or a mixture thereof.

  Examples of the homopolyamide include polycaprolactam (nylon 6), poly-ω-aminoheptanoic acid (nylon 7), poly-ω-aminononanoic acid (nylon 9), polyundecanamide (nylon 11), and polylaurin lactam. (Nylon 12), Polyethylenediamine adipamide (Nylon 2,6), Polytetramethylene adipamide (Nylon 4,6), Polyhexamethylenediadipamide (Nylon 6,6), Polyhexamiethylene sebacamide (Nylon 6,10), Polyhexamethylene decanamide (Nylon 6,12), Polyoctamethylene adipamide (Nylon 8,6), Polydecamethylene adipamide (Nylon 10,6), Polydecamethylene Bacamide (nylon 10,10), polydecamethylene dodecamide (nylon 12 12), metaxylenediamine-6 nylon (MXD6), and the like.

  Examples of the copolyamide include caprolactam / laurin lactam copolymer, caprolactam / hexamethylene diammonium adipate copolymer, laurin lactam / hexamethylenediamine ammonium sebacate copolymer, hexamethylene diammonium adipate / hexamethy Examples thereof include a range ammonium sebacate copolymer and a caprolactam / hexamethylene diammonium adipate / hexamethylene diammonium sebacate copolymer.

  Such a polyamide-based resin film substrate 111 may further contain materials other than polyamide, for example, plasticizers, low elastic modulus elastomers, lactams, or mixtures thereof.

  As the plasticizer, for example, aromatic sulfonamides, p-hydroxybenzoic acid, or esters can be used. As an elastomer having a low elastic modulus, for example, an ionomer resin, a modified polyolefin resin, a thermoplastic polyurethane, a polyether block amide, a polyester block amide, a polyether ester amide elastomer, a modified acrylic rubber, or a modified ethylene propylene rubber is used. be able to.

  Although there is no restriction | limiting in the thickness of the polyamide-type resin film base material 111, it needs to have the thickness which can ensure sufficient intensity | strength as a base material. However, when the polyamide resin film substrate 111 is too thick, the flexibility may be insufficient. Therefore, the thickness of the polyamide-based resin film substrate 111 is preferably in the range of about 10 μm to 100 μm, for example.

  On the other hand, the easy adhesion layer 112 is a layer formed on one surface of the polyamide-based resin film substrate 111. This easy-adhesion layer 112 is provided in order to improve the adhesion between the inorganic oxide vapor-deposited thin film layer 114 and the film base 111 together with the anchor coat layer 113 laminated adjacent thereto. And the easy-adhesion layer 112 is a polyamide in the case where the content containing a liquid is preserve | saved for a long time using the packaging material produced mainly with the gas barrier film of this invention with the anchor coat layer 113, for example. It works so as to suppress a decrease in adhesion of the inorganic oxide vapor-deposited thin film layer 114 to the resin film substrate 111.

  Examples of the constituent material of the easy-adhesion layer 112 include, for example, a water-dispersible polyester polyurethane containing adipic acid as a polyester dibasic acid, a prepolymer thereof, and a water-dispersible polyester polyurethane containing adipic acid as a polyester dibasic acid. Specific examples include a coating solution containing a polyurea resin, a prepolymer thereof, or a mixture containing two or more thereof as a main component. In order to improve the adhesion, a hydroxyl group, a carboxy group, or an amino group may be introduced into the main chain or terminal of the polymer contained in the coating liquid having such a composition.

  The above-mentioned coating liquid may further contain bisphenol glycidyl ether. Bisphenol glycidyl ether is a curing agent that accelerates curing of the main component of the coating liquid. By using bisphenol glycidyl ether, cross-linking is caused, whereby the easy-adhesion layer 112 excellent in water resistance, heat resistance, adhesiveness and film cohesion is obtained.

  As the bisphenol glycidyl ether, for example, a product obtained by reacting a bisphenol with epichlorohydrin and epoxidizing the molecular end of the reactive organism can be used. Examples of bisphenols include 4,4′-dihydroxy-phenylmethane, 1,1-bis (4-hydroxy-diphenyl) -ethane, 2,2-bis (4-hydroxy-diphenyl) -ethane, 2,2 -Bis (4-hydroxyphenyl) -propane, 1,1-bis (4-hydroxyphenyl) -n-butane, or bis (4-hydroxyphenyl) -cyclohexyl-methane can be used. Among these, 2,2-bis (4-hydroxyphenyl) -propane generally referred to as “bisphenol A” or 4,4′-dihydroxy-phenylmethane generally referred to as “bisphenol F” is preferable. Used.

  The easy-adhesion layer 112 is obtained, for example, by applying a coating film made of the coating liquid having the above-described components on the film base 111 and drying the coating film. In addition to the above-described components, this coating solution may further contain an additive. Examples of the additive include an antistatic agent, a lubricant, an antifoaming agent, and a surfactant. In addition, for example, a gravure roll method, a reverse gravure coat method, a roll coat method, an air knife method, a Mayer bar coat method, an inverse roll method, or the like can be used for applying the coating liquid.

  Prior to the application of the coating liquid, the surface to be coated of the polyamide resin film substrate 111 may be pretreated in order to improve wettability and / or adhesion. Examples of the pretreatment include corona discharge treatment and plasma treatment.

  When the polyamide-based resin film substrate 111 is stretched, the coating liquid for forming the easy-adhesion layer 112 may be applied to the stretched film substrate 111, and the polyamide-based resin film is being stretched. You may make it apply | coat to. The latter method is highly productive and efficient, and the easy-adhesion layer 112 is heat-treated at a high temperature in this stretch film formation step. Therefore, it easily adheres to the polyamide-based resin film substrate 111 as compared with the former method. The adhesion with the layer 112 can be further increased.

  In order to form the easy-adhesion layer 112 during the process of stretching and forming the polyamide resin film, for example, the following method can be used.

  First, a coating film of a coating liquid for forming the easy-adhesion layer 112 is applied on a polyamide resin film, and after preheating, a polyamide resin film is simultaneously biaxially stretched together with the coating film. Then, an easy adhesion 112 may be provided on the film substrate 111 by performing a heat setting process.

  Further, as another method for forming the easy-adhesion layer 112 during the stretching film forming step, for example, a sequential biaxial stretching method can be exemplified. In this method, first, a polyamide-based resin film is passed through heating rollers having different peripheral speeds to perform longitudinal stretching, and subsequently, a coating liquid for forming the easy-adhesion layer 112 on the longitudinally stretched polyamide-based resin film is applied. After the film is applied, the easy-adhesion layer 112 may be provided on the film substrate 111 by performing a transverse stretching process and further performing a heat setting process.

  The thickness of the easy adhesion layer 112 thus provided is preferably in the range of about 0.01 μm to 0.2 μm, for example. It is difficult to form a thin layer as a continuous film having a uniform thickness, and it is difficult to obtain sufficient adhesion. Further, when the layer is made thicker, the effect of improving the adhesiveness accompanying the increase in the film thickness is reduced. Therefore, an excessively thick easily adhesive layer is not economical.

  On the other hand, the anchor coat layer 113 is formed on the easy adhesion layer 112, and improves the adhesion between the vapor deposition thin film layer 114 of inorganic oxide and the film substrate 111 together with the easy adhesion layer 112.

  Such an anchor coat layer 113 is a layer comprising, for example, a reaction product of an acrylic polyol, an isocyanate compound, and a metal alkoxide or a hydrolysis product thereof.

A metal alkoxide is a compound represented by the general formula M (OR) _n . Here, M represents a metal such as titanium, aluminum, or zirconium, or silicon, and R represents an alkyl group such as a CH ₃ group or a C ₂ H ₅ group. N represents the valence of the element M.

When alkoxysilane is used as such a metal alkoxide, for example, a compound represented by the general formula Si (OR ¹ ) ₄ or R ² Si (OR ³ ) ₃ or a mixture thereof can be used. Here, R ¹ and R ³ represent a hydrolyzable group such as a CH ₃ group, a C ₃ H ₅ group, or a C ₂ H ₄ OCH ₃ group, and R ² represents an organic functional group.

  Specific examples of the alkoxysilane include vinyltrimethoxysilane, γ-chloropropylmethyldimethoxysilane, γ-chloropropyltrimethoxysilane, glycidoxypropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ- And methacryloxypropylmethyldimethoxysilane. In addition, those containing isocyanate groups such as isocyanate propyl triethoxy silane and γ-isocyanato propyl trimethoxy silane, those containing mercapto groups such as γ-mercapto propyl triethoxy silane, γ-aminopropyl triethoxy silane, γ Those containing an amino group such as -aminopropyltrimethoxysilane, N-β- (aminoethyl) -γ-aminopropyltriethoxysilane, and γ-phenylaminopropyltrimethoxysilane may be used.

  Furthermore, those containing an epoxy group such as γ-glycidoxypropyltrimethoxysilane and β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, vinyltrimethoxysilane, vinyltris (β-methoxyethoxy) silane It is also possible to add a hydroxyl group or the like by adding an alcohol or the like to a metal alkoxide such as. Two or more of these may be used.

  In these alkoxysilanes, an organic functional group present at one end exhibits an interaction by mixing two or more types of alkoxysilanes. Furthermore, the surface of the inorganic oxide vapor-deposited thin film layer 114 has a highly polar hydroxyl group and the like. By exhibiting strong interaction, high adhesion to the vapor-deposited thin film layer of the inorganic oxide and the film substrate 111 and the easy-adhesion layer 112 can be obtained, and the desired physical properties can be obtained.

  More preferably, the anchor coat layer 113 contains at least two kinds of metal alkoxides. In this case, when one type of metal alkoxide is an alkoxysilane containing an amino group, as the metal alkoxide other than the alkoxysilane containing an amino group, a compound having a functional group capable of reacting with an amino group (compound) (A)) is preferable. A functional group here is an epoxy group, a carboxyl group, an isocyanate group, an oxazolinyl group, or the like.

Specific examples of such compound (A) include phenyl glycidyl ether, 2-ethylhexyl glycidyl ether, glycerol diglycidyl ether, trimethylolpropane diglycidyl ether, resorcinol diglycidyl ether, neopentyl glycol diglycidyl ether, 1,6 -Hexanediol diglycidyl ether, ethylene glycol diglycidyl ether, diethylene glycol diglycidyl ether, triethylene glycol diglycidyl ether, tetraethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, hydroquinone diglycidyl ether, bisphenol A diglycidyl ether, bisphenol S diglycidyl ether, pentaerythritol tetragly Glycidyl ethers such as diether, glycidyl esters such as adipic acid diglycidyl ester, phthalic acid diglycidyl ester, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, β- (3,4-epoxycyclohexyl) Ethyltriethoxysilane, β- (3,4-epoxycyclohexyl) ethyltriisopropoxysilane, β- (3,4-epoxycyclohexyl) ethylmethyldimethoxysilane, β- (3,4-epoxycyclohexyl) ethylmethyldiethoxy Silane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropyltriisopropoxysilane, γ-glycidoxypropylmethyldimethoxysilane, γ-glycidoxypropyl Me Silane coupling agent having an epoxy group such as tildiethoxysilane and Si (OR ⁴ ) group (R ⁴ represents a hydrogen atom, a lower alkyl group or an acyl group), γ-isocyanopropyltrimethoxysilane, γ -Isocyanate groups such as isocyanopropyltriethoxysilane, γ-isocyanopropylmethyldimethoxysilane, γ-isocyanopropylmethyldiethoxysilane, and Si (OR ⁴ ) groups (R ⁴ is a hydrogen atom, a lower alkyl group or an acyl group) Group) Silane coupling agent, tolylene diisocyanate, 1,4-diphenylmethane diisocyanate, 1,5-naphthalene diisocyanate, triphenylmethane triisocyanate, tolidine diisocyanate, xylylene diisocyanate, dicyclohexylmethane diisocyanate Door, isocyanates such as hexamethylene diisocyanate, and the like. And these 1 type (s) or 2 or more types can be used. In addition, the compound (A) may be a polymer organic compound having a functional group capable of reacting with an amino group, or a polymer organic compound having a Si (OR ⁴ ) group.

  Examples of the solvent of the coating liquid mainly composed of the above-described components include esters such as ethyl acetate and butyl acetate, alcohols such as methanol, ethanol and isopropyl alcohol, ketones such as methyl ethyl ketone, and aromatic hydrocarbons such as toluene and xylene. , Water, or a mixture thereof can be used.

  The coating liquid may further contain an additive. Examples of additives include tertiary amines, imidazole derivatives, metal salt compounds of carboxylic acids, curing accelerators such as quaternary ammonium salts and quaternary phosphonium salts, phenol-based, sulfur-based and phosphite-based antioxidants, A leveling agent, a rheology modifier, a catalyst, a crosslinking reaction accelerator, a filler, or a mixture thereof can be used.

  A general coating method can be used for coating the coating liquid having such a composition on the easy-adhesion layer 112. For example, a dipping method, a roll coating method, a gravure coating method, a reverse coating method, an air knife coating method, a comma coating method, a die coating method, a screen printing method, a spray coating method, or a gravure offset method can be used.

  Prior to application of the coating liquid, for example, the surface of the easy-adhesion layer 112 may be pretreated in order to improve wettability and / or adhesion. Examples of the pretreatment include corona discharge treatment and plasma treatment.

  When the coating film of the coating liquid is thin, it is difficult to form a continuous film having a uniform thickness, and sufficient adhesion may not be obtained. Further, a thick coating film of the coating liquid has low flexibility, and there is a possibility that a crack will occur when the gas barrier film 11 is bent or pulled. Therefore, the thickness of the anchor coat layer 113 is preferably in the range of about 0.01 μm to 1 μm, for example. A range of about 0.05 μm to 0.5 μm is more preferable.

The inorganic oxide vapor-deposited thin film layer 114 laminated on the anchor coat layer 113 is made of an inorganic oxide vapor-deposited thin film such as aluminum oxide, silicon oxide, tin oxide, magnesium oxide, or a mixture thereof. What is necessary is just to have transparency and a gas barrier property against oxygen, water vapor and the like. Among them, those made of aluminum oxide or silicon oxide are particularly preferable. However, the vapor-deposited thin film layer 114 of inorganic oxide is not limited to the above-described inorganic oxide, and other inorganic oxides can be used as long as the material meets the above conditions.

  The optimum thickness of the inorganic oxide vapor-deposited thin film layer 114 varies depending on the type and configuration of the inorganic oxide used, but is generally in the range of about 5 to 300 nm, and the value can be appropriately selected. However, if the film thickness is less than 5 nm, a uniform film may not be obtained or the film thickness may not be sufficient, and the function as a gas barrier material may not be sufficiently achieved. Further, when the film thickness exceeds 300 nm, it is difficult to maintain flexibility in the vapor-deposited thin film layer of inorganic oxide, and if an external force such as bending or pulling is applied after the film formation, there is a risk of cracking. Preferably, it may be in the range of about 10 to 150 nm.

  Various means can be adopted as means for forming the inorganic oxide vapor-deposited thin film layer 114 on the anchor coat layer 113, but it is generally formed by vacuum vapor deposition. Sputtering, ion plating, plasma vapor deposition (CVD), etc. can be used as means other than this vacuum vapor deposition. However, considering productivity, the vacuum deposition method is the best at present. Any one of an electron beam heating method, a resistance heating method, and an induction heating method may be appropriately used as a heating means of the vacuum evaporation apparatus by this vacuum evaporation method. In order to improve the adhesion between the inorganic oxide vapor-deposited thin film layer 114 and the film substrate 111 and the denseness of the inorganic oxide vapor-deposited thin film layer, it is also possible to use a plasma assist method or an ion beam assist method. . In addition, in order to increase the transparency of the vapor-deposited thin film layer of inorganic oxide, it is possible to carry out reactive vapor deposition by blowing oxygen gas or the like during vapor deposition.

  On the other hand, as a material for forming the gas barrier film 115 laminated on the inorganic oxide vapor-deposited thin film layer 114, for example, a material composed of a water-soluble polymer and one or more metal alkoxides and / or a hydrolyzate thereof, Furthermore, the coating liquid in which the said metal alkoxide consists of any of tetraethoxysilane, triisopropoxy aluminum, or these mixtures can be mentioned as a specific example. Other examples of the gas barrier coating layer 115 that imparts a high gas barrier property include those comprising a water-soluble polymer and tin chloride, and further the coating film of the coating liquid comprising the water-soluble polymer comprising polyvinyl alcohol. And the resulting film. More specifically, a coating solution in which a water-soluble polymer and tin chloride are dissolved in an aqueous (water or water / alcohol mixed) solvent, or a solution obtained by hydrolyzing a metal alkoxide directly or in advance is mixed with this solution. Examples thereof include a film formed by coating a solution coating film on an inorganic oxide vapor-deposited thin film layer 114 and drying by heating. Hereinafter, the coating liquid having the above-described composition for forming the gas barrier coating layer 115 will be described in more detail.

  Specific examples of the water-soluble polymer constituting the coating solution include polyvinyl alcohol, polyvinyl pyrrolidone, starch, methyl cellulose, carboxymethyl cellulose, sodium alginate and the like. In particular, when polyvinyl alcohol (hereinafter referred to as PVA) is used, the gas barrier properties are most excellent. The PVA here is generally obtained by saponifying polyvinyl acetate, and includes from so-called partially saponified PVA in which several dozen percent of acetate groups remain to complete PVA in which only several percent of acetate groups remain. However, the type is not particularly limited.

The tin chloride may be stannous chloride (SnCl ₂ ), stannic chloride (SnCl ₄ ), or a mixture thereof, and may be used as an anhydride or a hydrate.

Further, the metal alkoxide is represented by a general formula such as tetraethoxysilane [Si (OC ₂ H ₅ ) ₄ ], triisopropoxy aluminum [Al (O-2′-C ₃ H ₇ ) ₃ ], M (OR) _n
(M: metal such as Si, Ti, Al and Zr, R: alkyl group such as CH ₃ and C ₂ H ₅ ). Among these, tetraethoxysilane and triisopropoxyaluminum are preferable because they are relatively stable in an aqueous solvent after hydrolysis.

  The gas barrier coating layer 115 can be formed by applying a thin film of the coating liquid containing the above-described components onto the vapor-deposited thin film layer of inorganic oxide and drying it. As long as the gas barrier property is not impaired, additives such as an isocyanate compound, a silane coupling agent, a dispersant, a stabilizer, a viscosity modifier, and a colorant may be added to the coating liquid.

  For example, the isocyanate compound added to the coating liquid that constitutes the gas barrier coating layer 115 has two or more isocyanate groups (NCO groups) in the molecule, such as tolylene diisocyanate (hereinafter referred to as TDI), Examples thereof include monomers such as phenylmethane triisocyanate (hereinafter referred to as TTI) and tetramethylxylene diisocyanate (hereinafter referred to as TMXDI), and polymers or derivatives thereof.

  Conventionally known thin film forming means such as a dipping method, a roll coating method, a screen printing method, and a spray method can be used as a coating method of the coating liquid for forming the gas barrier film layer 115. Further, the thickness of the gas barrier coating layer 115 varies depending on the type of coating liquid for forming the coating layer and the processing conditions, but the thickness after drying may be 0.01 μm or more. However, if the thickness is 50 μm or more, cracks are likely to occur in the film, and therefore it is preferably in the range of about 0.01 to 50 μm.

  Another layer can be further laminated on the inorganic oxide vapor-deposited thin film layer 114 or the gas barrier coating 115. For example, a printing layer, an intervening film layer, a heat seal layer, and the like.

  The printing layer is provided for practical use as a packaging material or packaging bag, and various types of conventionally used ink binder resins such as urethane, acrylic, nitrocellulose, rubber and vinyl chloride. Letters, designs, and the like composed of inks to which additives such as pigments, extender pigments, plasticizers, desiccants, and stabilizers are added. Examples of the forming method include known printing methods such as an offset printing method, a gravure printing method, and a silk screen printing method. The thickness may be about 0.1 to 2.0 μm.

  Further, the intervening film layer is a breakage required when, for example, a boil treatment or a retort sterilization treatment is performed on a packaging bag made of a packaging material comprising the gas barrier film of the present invention as a main constituent material. The layer is provided to increase the bag strength. For example, it is a layer composed of a biaxially stretched nylon film, a biaxially stretched polyethylene terephthalate film, a biaxially stretched polypropylene film, etc. in consideration of mechanical strength and thermal stability. The thickness is determined according to the material, required quality, and the like, but generally may be about 10 to 30 μm.

The general structure of the composite layer constituting the gas barrier film of the present invention has been described above. The composite layer has a surface roughness Rz (ten-point average roughness) of 5 nm or less and about 1 μm square. It is necessary that the surface area of is 101000 nm ² or less. These numerical values can be obtained from images measured with a commercially available scanning probe microscope (hereinafter referred to as “SPM”). Here, the roughness means the roughness of minute irregularities existing on a large waviness in the measurement area.

The inorganic oxide vapor-deposited thin film layer located at the uppermost layer of the composite layer is formed by depositing inorganic oxide particles deposited thereon more densely and without gaps, thereby providing a gas barrier property. improves. In particular, when the surface roughness Rz (ten-point average roughness) of the surface of the vapor-deposited thin film layer of the inorganic oxide constituting the composite layer is 5 nm or less and the surface area per 1 μm square is 101000 nm ² or less, the thin film particles are dense. The adhesion between the inorganic oxide vapor-deposited thin film layer 114 and the film base 111 is further improved.

  Preparation conditions such as coating conditions for forming an easy-adhesion layer and anchor coat, and stretching conditions after application, etc. In addition, by appropriately selecting the type and composition of each of the coating liquids described above and producing the gas barrier film of the present invention, a composite layer having such surface roughness characteristics can be provided. That's fine.

  Further, the surface of the film base, the surface of the easy-adhesion layer or the anchor coat layer may be appropriately roughened by sputtering or plasma before film formation.

  Hereinafter, an embodiment of the present invention will be described in more detail with reference to the drawings. However, the present invention is not limited thereto.

First, a coating liquid A1 for forming an easy adhesion layer, coating liquids B1 to B3 for forming an anchor coat layer, and a coating liquid C1 for forming a gas barrier film layer were prepared as follows.
<Preparation of coating liquid Al>
An aqueous solution containing a water-dispersible polyester polyurethane containing adipic acid as a dibasic acid component of polyester and bisphenol A glycidyl ether at a solid mass ratio of 100: 6 was prepared as coating liquid Al.
<Preparation of coating solution B1>
An equal amount of bis (3-triethoxysilylpropyl) amine and vinyltriethoxysilane is mixed, and this mixed solution is added to a mixture of water and ethanol to prepare a solid content of 10%, and coating solution B1 It was.
<Preparation of coating solution B2>
Bis (3-triethoxysilylpropyl) amine and vinyltriethoxysilane are mixed at a mass ratio of 70:30, and this mixture is added to a mixture of water and ethanol so that the solid content becomes 7%. To prepare a coating solution B2.
<Preparation of coating solution B3>
A 7 g ethyl acetate solution containing a polyester resin having a hydroxyl value of 5 mg KOH / g at a concentration of 20% by mass was prepared. To this solution, 1.5 g of a mixture containing xylylene diisocyanate and isophorone diisocyanate at a mass ratio of 80:20 was mixed. Next, this solution was diluted with ethyl acetate so that the solid content concentration was 2% by mass, and further stirred for 10 minutes to obtain a coating solution B3.
<Preparation of coating liquid C1>
First, 90 g of 0.1N hydrochloric acid aqueous solution was added to 10 g of tetraethoxysilane. Next, this mixed solution was stirred for 30 minutes to cause hydrolysis of tetraethoxysilane. Thus, to obtain a hydrolysis solution containing a concentration of 3 wt% solids in terms of SiO _2. Next, PVA, water, and isopropyl alcohol were mixed to prepare a 65 g PVA solution. The mass ratio of water to isopropyl alcohol was 90:10. The PVA concentration of this PVA solution was 4% by mass.

  These hydrolysis solution and PVA solution were mixed to prepare a coating solution, which was designated as coating solution C1.

Then, transparent gas barrier film BF1-10 was produced as follows.
<Preparation of transparent gas barrier film BF1>
First, an unstretched film made of nylon 6 and having a thickness of 150 μm was formed by a T-die method.

  Next, a coating film of the coating liquid A1 was applied on one surface of the film by the Meyer bar coating method. After the coating film was dried, the unstretched film was simultaneously biaxially stretched so as to be 3.0 times in the longitudinal direction and 3.3 times in the transverse direction. And the heat setting process was performed at the temperature of 210 degreeC, and the 15-micrometer-thick film base material which has an easily bonding layer whose thickness is 0.05 micrometer on one surface was obtained.

  Then, the coating film of coating liquid B1 was apply | coated by the gravure coating method on the easily bonding layer. And the anchor coat layer whose thickness is 0.05 micrometer was obtained by drying this coating film.

  Subsequently, an inorganic oxide vapor-deposited thin film layer made of silicon oxide having a thickness of 50 nm was formed on the anchor coat layer by a vacuum vapor deposition device using a resistance heating method, to obtain a transparent gas barrier film BF1.

About the surface of the vapor-deposited thin film layer of the obtained inorganic gas barrier film BF1 using a scanning probe microscope (SPM) Seiko Instruments Inc. SPI-3800N, measurement mode: DFM, cantilever: SI-DF20, The surface shape was measured in a measurement range of 1 × 1 μm, and the surface roughness and surface area were measured. The surface roughness Rz (ten-point average roughness) was 4.18 nm, and the surface area per 1 μm square was 100900 nm ² .
<Preparation of transparent gas barrier film BF2>
A method for producing the transparent gas barrier film BF1 except that after the coating film of the coating liquid B2 is applied on the anchor coat layer, this coating film is dried to form an anchor coat layer having a thickness of 0.04 μm. A transparent gas barrier film BF2 was produced by the same method as described above. The inorganic oxide layer had a surface roughness Rz (10-point average roughness) of 4.52 μm and a surface area per 1 μm square of 102000 nm ² .
<Preparation of transparent gas barrier film BF3>
A method for producing the transparent gas barrier film BF1 except that after the coating film of the coating liquid B3 is applied on the anchor coat layer, the anchor coat layer having a thickness of 0.03 μm is formed by drying the coating film. A transparent gas barrier film BF3 was produced by the same method as described above. The inorganic oxide layer had a surface roughness Rz (10-point average roughness) of 6.31 μm and a surface area per 1 μm square of 100800 nm ² .
<Preparation of transparent gas barrier film BF4>
A transparent gas barrier film BF4 was produced by the same method as the production method of the transparent gas barrier film BF3, except that the easy adhesion layer was not formed by the coating liquid Al. The inorganic oxide layer had a surface roughness Rz (10-point average roughness) of 7.34 μm and a surface area per 1 μm square of 102800 nm ² .
<Preparation of transparent gas barrier film BF5>
The thin film of the coating liquid C1 is applied by the gravure coating method onto the vapor-deposited thin film layer of the inorganic oxide of the transparent gas barrier film produced by the same method as the transparent gas barrier film BF1, and then the coating film is heated and dried. As a result, a transparent gas barrier film BF5 having a gas barrier film layer having a thickness of 0.3 μm was obtained. The surface roughness Rz (10-point average roughness) of the vapor-deposited thin film layer of the inorganic oxide of the transparent gas barrier film BF5 was 4.31 μm, and the surface area per 1 μm square was 100800 nm ² .
<Preparation of transparent gas barrier film BF6>
A method for producing the transparent gas barrier film BF5, except that after the coating film of the coating liquid B2 was applied on the anchor coat layer, this coating film was dried to obtain an anchor coat layer having a thickness of 0.05 μm. A transparent gas barrier film BF6 was produced by the same method as described above. The surface roughness Rz (10-point average roughness) of the vapor-deposited thin film layer of the inorganic oxide of the transparent gas barrier film BF6 was 4.27 μm, and the surface area per 1 μm square was 100700 nm ² .
<Preparation of transparent gas barrier film BF7>
A method for producing the transparent gas barrier film BF5, except that after the coating film of the coating liquid B3 was applied on the anchor coat layer, this coating film was dried to obtain an anchor coat layer having a thickness of 0.035 μm. A transparent gas barrier film BF7 was produced by the same method as described above. The surface roughness Rz (ten-point average roughness) of the inorganic oxide vapor-deposited thin film layer of the transparent gas barrier film BF7 was 4.82 μm, and the surface area per 1 μm square was 102300 nm ² .
<Preparation of transparent gas barrier film BF8>
A transparent gas barrier film BF8 was produced by the same method as the production method of the transparent gas barrier film BF7 except that the easy adhesion layer was not provided. The surface roughness Rz (10-point average roughness) of the vapor-deposited thin film layer of the inorganic oxide of the transparent gas barrier film BF8 was 10.50 μm, and the surface area per 1 μm square was 100900 nm ² .
<Preparation of transparent gas barrier film BF9>
Instead of forming an inorganic oxide vapor-deposited thin film layer made of silicon oxide with a thickness of 50 nm by a vacuum vapor deposition device using a resistance heating method, the thickness made of aluminum oxide is made by a vacuum vapor deposition device using an electron beam heating method. A transparent gas barrier film BF9 was produced by the same method as the production method of the transparent gas barrier film BF5 except that a deposited thin film layer of 15 nm inorganic oxide was formed. The surface roughness Rz (10-point average roughness) of the vapor-deposited thin film layer of the inorganic oxide of the transparent gas barrier film BF9 was 4.85 μm, and the surface area per 1 μm square was 100700 nm ² .
<Preparation of transparent gas barrier film BF10>
A transparent gas barrier film BF10 was produced by the same method as the production method of the transparent gas barrier film BF9 except that the easy adhesion layer was not provided. The surface roughness Rz (10-point average roughness) of the vapor-deposited thin film layer of the inorganic oxide of the transparent gas barrier film BF10 was 12.65 μm, and the surface area per 1 μm square was 101,200 nm ² .

  Table 1 shows the measurement results of the surface roughness and the surface area of the transparent gas barrier films BF1 to 10 produced as described above, together with the oxygen permeability.

表１に示の結果より、実施例ＢＦ１は、ＢＦ２〜４よりバリア性が優れていること、ＢＦ５、６はＢＦ７、８よりガスバリア性が優れていること、ＢＦ９はＢＦ１０よりガスバリア性が優れていることがわかる。ＢＦ７、８、１０はガスバリア性被膜層を有しているが、それでも１０ｃｃ前後の値であり、ガスバリア性が十分ではない。すなわち、表面粗さＲｚ（十点平均粗さ）が５μｍ以下であり、かつ１μｍ角あたりの表面積が１０１０００ｎｍ²以下であるバリアフィルム以外は、ガスバリア性が十分ではない。

From the results shown in Table 1, Example BF1 has better barrier properties than BF2-4, BF5, 6 has better gas barrier properties than BF7, 8, and BF9 has better gas barrier properties than BF10. I understand that. BF7, 8, and 10 have a gas barrier coating layer, but still have a value of around 10 cc, and the gas barrier property is not sufficient. That is, the gas barrier property is not sufficient except for a barrier film having a surface roughness Rz (10-point average roughness) of 5 μm or less and a surface area per 1 μm square of 101000 nm ² or less.

It is explanatory drawing which shows the general | schematic cross-section structure of the transparent gas barrier film which concerns on one Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 ... Transparent gas barrier film 111 ... Polyamide-type resin film base material 112 ... Easy-adhesion layer 113 ... Anchor coat layer 114 ... Deposition thin film layer 115 of an inorganic oxide ... Gas barrier film layer

Claims (7)

At least one composite layer in which an easy-adhesion layer, an anchor coat layer, and an inorganic oxide vapor-deposited thin film layer are sequentially laminated is provided on at least one surface of the polyamide-based resin film substrate, and the surface of the composite layer A gas barrier film having a surface roughness Rz (ten-point average roughness) of 5 nm or less and a surface area per 1 μm square of 101000 nm ² or less.   The gas barrier film according to claim 1, wherein the easy adhesion layer contains nitrogen atoms, adipic acid, and bisphenol glycidyl ether.   The gas barrier film according to claim 1 or 2, wherein the anchor coat layer contains a reaction product of an acrylic polyol, an isocyanate compound, and a metal alkoxide or a hydrolysis product thereof.   The gas barrier film according to any one of claims 1 to 3, wherein the inorganic oxide is any one of aluminum oxide, silicon oxide, magnesium oxide, or a mixture thereof.   The inorganic oxide vapor-deposited thin film layer of the composite layer contains water, a water-soluble polymer, at least one compound selected from the group consisting of metal alkoxides, hydrolysis products thereof, and tin chloride. The gas barrier film according to any one of claims 1 to 4, further comprising a gas barrier film layer which is a dry film of a thin film made of a coating liquid.   A thin film made of a coating solution containing a water-soluble polymer, tetraalkoxysilane or a hydrolysis product thereof, and trialkoxysilane or a hydrolysis product thereof is formed on the inorganic oxide vapor deposition thin film layer of the composite layer. The gas barrier film according to any one of claims 1 to 4, further comprising a gas barrier film layer which is a dry film.   The gas barrier film according to claim 6, wherein the organic functional group other than the alkoxy group bonded to silicon of the trialkoxysilane of the coating liquid is a hydrophobic organic functional group.

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