JP2008087380A - Barrier film and packaging material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a barrier film which employs a polyamide type resin substrate film, combines transparency and gas barrier nature and has superior adhesion to the ink on printing on the outermost layer and excellent adhesion to the adhesive when used as the middle layer of a three-layer structure. <P>SOLUTION: The barrier film has a vapor-deposited layer of an inorganic compound on one surface of a polyamide type resin substrate film, and the other surface without the vapor deposition layer has an O(oxygen)/C(carbon) elemental ratio of 0.16-0.26, measured by the X-ray photoelectron spectroscopy with an X-ray source of MgKα and an X-ray output of 100W. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a barrier film used for packaging foods, pharmaceuticals, medical devices, electronic parts, and the like, and more particularly, polyamides which are suitably used for improving the thickness of surface printing, particularly for the middle-use three-layer structure. The present invention relates to a barrier film using a base film made of a resin.

  In recent years, the packaging form of foods has changed drastically, and product quality degradation due to temperature changes, moisture, oxygen, etc. in the distribution and sales process is a major problem not only from sales loss but also from food sanitation. It is. Under such circumstances, there is an increasing demand for packaging films that have low gas and moisture permeability and that do not cause quality deterioration as a food product due to boil sterilization or retort sterilization.

  In other words, it is important to maintain the taste and freshness by suppressing the oxidation and alteration of proteins and fats in food ingredients. To that end, it is necessary to block the permeation of air using packaging materials with good gas barrier properties. Is desired. Moreover, packaging with a gas barrier film retains the fragrance of the contents and prevents moisture permeation, so moisture-absorbing deterioration is suppressed for dried products, and alteration and solidification due to moisture volatilization are suppressed for hydrated materials. It is possible to maintain a fresh flavor during packaging for a long time.

  For these reasons, gas barrier properties and moisture resistance required for packaging films are extremely important characteristics. These characteristics are not limited to the film for food packaging described above, but are also extremely important for medical films that require aseptic handling and packaging films for electronic parts that require rust prevention. It becomes.

  As a gas barrier packaging material, from the viewpoint of protecting the package contents, and on a polyamide-based resin base film having excellent protection against piercing, bending resistance, wear resistance, etc. A laminate of metal foil, a coating of vinylidene chloride, a laminate of ethylene vinyl alcohol copolymer or metaxylylenediamine-6 nylon by coextrusion are known. In recent years, a transparent barrier film in which silicon oxide, aluminum oxide or the like is vapor-deposited on a polyamide-based resin base film is also known as a film using an inorganic thin film other than metal.

  Packaging materials using metal foils such as aluminum as the gas barrier layer have good gas barrier properties and excellent economics, but they must be treated as non-combustible materials when discarded after use. Since the contents cannot be checked, it is difficult to check for defective seals during filling seals, foreign objects cannot be detected with a metal detector, and microwaves cannot be processed, so microwaves cannot be processed. There was a problem.

  Packaging materials coated with vinylidene chloride as a gas barrier layer are inexpensive and economical, but the gas barrier properties against water vapor, oxygen, etc. are not sufficient, especially the performance degradation during high-temperature treatment is significant, and dioxins are generated during incineration. Contamination problems also arise.

  The packaging material in which ethylene vinyl alcohol copolymer or metaxylylenediamine-6 nylon is laminated by coextrusion as a gas barrier layer can be subjected to boil sterilization or retort sterilization. Gas barrier performance deteriorates significantly under high temperature and humidity.

On the other hand, a transparent barrier film (see, for example, Patent Document 1) in which silicon oxide, aluminum oxide or the like is vapor-deposited on a polyamide-based resin base film, which has been put on the market in recent years, can be applied to a microwave oven because its contents can be seen. It is used as a film and has excellent gas barrier properties under normal conditions. When this transparent barrier film is used as a packaging material, it usually has a two-layer structure in which heat seal layers are laminated. However, when printing is performed on the surface on which the outermost polyamide-based resin vapor deposition film is not provided with the laminated film having the two-layer structure, there is a problem that the ink is not sufficiently adhered and the ink is removed. Moreover, when the boil sterilization process and the retort sterilization process were performed with the laminated film of 2 layer structure, there existed a problem that gas barrier performance was almost lost by shrinkage | contraction of a base material. As a countermeasure, there are cases where the transparent barrier film has a three-layer structure in which another base material and a heat seal layer are provided on both sides of the transparent barrier film, respectively, but a polyamide-based resin deposition film is not provided. There was a problem that the adhesion between the side surface and the adhesive was insufficient.
JP 49-41469 A

  An object of the present invention is a polyamide having transparency and gas barrier properties, excellent adhesion with ink when printing on the outermost layer, and excellent adhesion with an adhesive in the case of a three-layer configuration of medium use An object of the present invention is to provide a barrier film having a base resin base film.

  The invention according to claim 1 is a barrier film in which a vapor deposition layer made of an inorganic compound is provided on one side of a polyamide resin base film, and the surface of the polyamide resin base film on the side where no vapor deposition film is provided is X Barrier characterized in that an element ratio O (oxygen) / C (carbon) obtained by measurement under measurement conditions of an X-ray source MgKα and an X-ray output of 100 W by linear photoelectron spectroscopy is 0.16 to 0.26 It is a film.

  The invention according to claim 2 is the barrier film according to claim 1, wherein an anchor coat resin layer is provided between the polyamide-based resin base film and the vapor deposition layer made of the inorganic compound.

The invention according to claim 3 is characterized in that the anchor coat layer comprises an acrylic polyol, an isocyanate compound, and a general formula R′Si (OR) ₃ (R ′ is an alkyl group, a vinyl group, a glycidoxypropyl group, an amino group, an isocyanate group). 3. The barrier film according to claim 2, comprising a composition containing a trifunctional organosilane selected from the group consisting of a group and a sulfoxide group, wherein R is an alkyl group) or a hydrolyzate thereof. .

  In the invention according to claim 4, the surface of the polyamide-based resin base film on the side where the vapor deposition layer made of the inorganic compound is provided is a gas selected from the group consisting of argon, nitrogen, oxygen, hydrogen, and a mixed gas thereof. The barrier film according to any one of claims 1 to 3, wherein the barrier film has been subjected to a reactive ion etching (RIE) mode plasma treatment using bismuth.

  The invention according to claim 5 is the barrier film according to any one of claims 1 to 4, wherein a barrier coat resin layer is provided on a surface of the vapor deposition film.

  The invention according to claim 6 is an aqueous solution or water / alcohol mixture in which the gas barrier coating contains a water-soluble polymer and (a) at least one of metal alkoxide or a hydrolyzate thereof and (b) tin chloride. 6. The barrier film according to claim 5, wherein a coating agent containing a solution as a main component is applied and dried by heating.

The invention according to claim 7 is characterized in that the gas barrier coating comprises a water-soluble polymer, (a) at least one of a metal alkoxide or a hydrolyzate thereof and (b) tin chloride, and a general formula (R ₂ Si (OR ₁ ) ₃ ) _n (wherein R ₁ is selected from the group consisting of CH ₃ , C ₂ H ₅ and C ₂ H ₄ OCH ₃ , and R ₂ is an organic functional group). The barrier film according to claim 5, wherein the barrier film is formed by applying a coating agent mainly composed of an aqueous solution or a water / alcohol mixed solution, followed by heating and drying.

  In the invention according to claim 8, the printed layer is provided on the surface of the polyamide-based resin base film that constitutes the barrier film according to any one of claims 1 to 7 on the surface on which the deposited film is not provided. A packaging material characterized by

  The invention according to claim 9 is a packaging material, characterized in that a plastic film substrate and a heat seal layer are provided on both surfaces of the barrier film according to any one of claims 1 to 7 via an adhesive, respectively. It is.

  In order to increase the adhesion between the polyamide-based resin substrate film and the ink or adhesive, it is necessary to increase the wettability of the polyamide surface. The inventors of the present invention are controlling the wettability of the polyamide surface with the element ratio of O (oxygen atom) / C (carbon atom), and the element ratio of O (oxygen atom) / C (carbon atom). It has been found that optimum adhesion can be secured by limiting to a specific range.

  According to the present invention, a polyamide resin film substrate that exhibits excellent barrier properties under normal handling conditions, has excellent ink adhesion to the outermost layer, and adhesion with an adhesive, and does not impair gas barrier properties. Can be provided. Therefore, the barrier film according to the present invention can be effectively used widely for a wide range of packaging materials that require high gas barrier properties, including packaging materials for foods, pharmaceuticals, and industrial materials.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a cross-sectional view showing an example of a transparent gas barrier film 10 according to the present invention. As shown in FIG. 1, regarding the base film 1 made of a polyamide-based resin, the surface on the outermost layer side (surface modification side) is 1a, and the surface on the vapor deposition film side (content side) is 1b. An anchor coat layer 2, a transparent vapor deposition layer 3 made of an inorganic oxide, and a gas barrier coating 4 are sequentially laminated on the surface 1 b on the vapor deposition film side of the polyamide-based resin base film 1. At least the outermost layer side surface 1a of the base film 1 has an element ratio O (oxygen) / C (obtained by measurement under measurement conditions of an X-ray source MgKα and an X-ray output of 100 W by X-ray photoelectron spectroscopy (XPS). Carbon) is 0.16 to 0.26. In addition, the element ratio O (oxygen) / C (carbon) obtained by the measurement on the said measurement conditions is similarly 0.16-0.26 also on the surface 1b at the side of the vapor deposition film of the base film 1. FIG. .

  FIG. 2 is a cross-sectional view showing an example of a packaging material using the transparent gas barrier film of the present invention. As shown in FIG. 2, this packaging material is formed by applying a printed layer 11 to the outermost layer side surface 1a (shown in FIG. 1) of the polyamide-based resin base film 1 of the transparent gas barrier film 10 to provide a gas barrier coating 4 (FIG. 1). A heat-seal layer 13 is provided on an adhesive) via an adhesive 12.

  FIG. 3 is a cross-sectional view showing another example of a packaging material using the transparent gas barrier film of the present invention. As shown in FIG. 3, a plastic film substrate (for example, polyethylene terephthalate) 14 formed with a printing layer 11 and a heat seal layer 13 are bonded to both sides of the transparent gas barrier film 10 via adhesives 12 and 12, respectively. It is a thing.

  Hereinafter, the preferable actual condition of this invention is demonstrated in detail.

  The polyamide-based resin constituting the base film of the transparent gas barrier film is not particularly limited, and any of homopolyamide, copolyamide, a mixture thereof, or a crosslinked product thereof can be used.

  Specific examples of homopolyamide include polycaproamide (nylon 6), poly-ω-aminoheptanoic acid (nylon 7), poly-9-aminononanoic acid (nylon 9), polyundecanamide (nylon 11), polylaurin lactam (Nylon 12), polyethylenediamine adipamide (nylon 2,6), polytetramethylene adipamide (nylon 4,6), polyhexamethylenediadipamide (nylon 6,6), polyhexamethylene sebacamide ( Nylon 6,10), polyhexamethylene dodecamide (nylon 6,12), polyoctamethylene adipamide (nylon 8,6), polydecamethylene adipamide (nylon 10,6), polydecamethylene sebacamide (Nylon 10,10), Polydodecamethylene dodecamide (Nylon 12,12) Metaxylenediamine -6 nylon (MXD6) and the like.

  Specific examples of the copolyamide include caprolactam / laurin lactam copolymer, caprolactam / hexamethylene diammonium adipate copolymer, laurin lactam / hexamethylene diammonium adipate copolymer, hexamethylene diammonium adipate / hexamethylene diammonium seba Examples thereof include a keto copolymer, an ethylenediammonium adipate / hexamethylenediammonium adipate copolymer, and a caprolactam / hexamethylenediammonium adipate / hexamethylenediammonium sebacate copolymer.

  In the polyamide-based resin constituting the base film, other additives such as a plasticizer, a heat stabilizer, an ultraviolet absorber, an antioxidant, a colorant, a filler, an antistatic agent, an antibacterial agent, if necessary It is also possible to blend an appropriate amount of a lubricant, an anti-blocking agent, other resins and the like. Further, at least one side (contents side) of the polyamide-based resin film constituting the base film is subjected to corona treatment, low-temperature plasma treatment, or ion bombardment treatment as a pretreatment, as described later, and further chemical treatment, You may give a solvent process etc.

  The thickness of the base film is not particularly limited, but the suitability as a packaging material, that other layers may be laminated, and the workability when forming an anchor coat layer, an inorganic oxide thin film layer, and a gas barrier coating layer. In consideration, it is practically in the range of 1 to 80 μm, and preferably 10 to 50 μm depending on the application. Considering mass productivity, it is preferable to use a long film so that each layer can be formed continuously. Moreover, it is preferable that the base film is biaxially stretched.

  In the present invention, the surface of the polyamide-based resin base film on the side where the vapor deposition film is not provided is an element ratio O (oxygen) obtained by measurement under measurement conditions of an X-ray source MgKα and an X-ray output of 100 W by X-ray photoelectron spectroscopy. ) / C (carbon) is 0.16 to 0.26. This is intended to increase the adhesion of the ink or adhesive. Such a surface state can be obtained by modifying the surface by a treatment such as a corona treatment, a low temperature plasma treatment, or an ion bombardment treatment.

  The surface state of the polyamide resin substrate film is evaluated by measurement by X-ray photoelectron spectroscopy. An example of specific measurement conditions is shown below. X-ray photoelectron spectrometer: JPS-90MXV manufactured by JEOL Ltd., X-ray source: non-monochromated MgKα (1253.6 eV), output: 100 W (10 kV-10 mA). Quantitative analysis is performed by calculation using relative sensitivity factors of 2.28 for O1s and 1.00 for C1s. The typical element ratio O (oxygen) / C (carbon) of the polyamide-based resin base film before modification was 0.169.

Next, the other layer laminated | stacked on a polyamide-type resin base film is demonstrated.
An anchor coat layer is provided on a polyamide-type resin base film, and aims at improving the adhesiveness at the time of providing the vapor deposition layer which consists of inorganic oxides. As the anchor coat layer, urethane-polyester resin, polyurethane resin, phenol resin, polyester resin, urethane-modified alkyd resin, epoxy resin, acrylic resin, epoxy-modified acrylic resin, isocyanate compound, and general formula R′Si (OR ) ₃ (wherein R ′ is a functional group such as an amino group, isocyanate group or sulfoxide group, R is an alkyl group, etc.) and a complex with a hydrolyzate thereof is preferably used.

The anchor coat layer is preferably a metal alkoxide represented by the general formula M (OR) _n (where M is a metal atom, R is an alkyl group, and n is the oxidation number of the metal atom) or a hydrolyzate thereof, Trifunctional organo represented by the formula R′Si (OR) ₃ , where R ′ is an alkyl group, vinyl group, epoxy group, glycidoxypropyl group, amino group, isocyanate group, sulfoxide group, and R is an alkyl group. A composite of at least one of silane or a hydrolyzate thereof, a polyol compound such as polyester polyol or acrylic polyol, and an isocyanate compound can be used.

  As the trifunctional organosilane, one containing any organic functional group can be used. For example, vinyltrimethoxysilane, γ-chloropropylmethyldimethoxysilane, γ-chloropropyltrimethoxysilane, glycidoxypropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropylmethyldimethoxysilane, etc. One type or two or more types of functional organosilanes or hydrolysates thereof can be used.

  Among these trifunctional organosilanes, those having a functional group that reacts with a hydroxyl group of a polyol or an isocyanate group of an isocyanate compound are particularly preferable. For example, those containing an isocyanate group such as γ-isocyanatopropyltriethoxysilane, γ-isocyanatopropyltrimethoxysilane, those containing a mercapto group such as γ-mercaptopropyltriethoxysilane, γ-aminopropyltriethoxysilane, γ Some include amino groups such as aminopropyltrimethoxysilane, N-β- (aminoethyl) -γ-aminopropyltriethoxysilane, and γ-phenylaminopropyltrimethoxysilane. Further, those containing an epoxy group such as γ-glycidoxypropyltrimethoxysilane and β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, vinyltrimethoxysilane, vinyltris (β-methoxyethoxy) silane, etc. An alcohol or the like added to such a trifunctional organosilane and a hydroxyl group or the like may be added. Of these, one or more can be used.

  The trifunctional organosilane has an organic functional group at one end that interacts in a composite composed of a polyol and an isocyanate compound, and also includes a functional group that reacts with a hydroxyl group of the polyol or an isocyanate group of the isocyanate compound. To form a stronger primer layer by providing a covalent bond, and the alkoxy group at the other end or the silanol group generated by hydrolysis of the alkoxy group is formed on the metal in the inorganic oxide or on the surface of the inorganic oxide. High adhesion with an inorganic oxide is expressed by strong interaction with a highly polar hydroxyl group and the like, which is advantageous for obtaining desired physical properties. Accordingly, a trifunctional organosilane hydrolyzed with a metal alkoxide may be used as the primer layer. The alkoxy group of the trifunctional organosilane may be a chloro group, an acetoxy group, or the like. That is, as long as these alkoxy groups, chloro groups, acetoxy groups, etc. are hydrolyzed to form silanol groups, such trifunctional organosilanes can be used in the composite.

  A polyol has two or more hydroxyl groups at the polymer terminal and reacts with an isocyanate group of an isocyanate compound added later. As the polyol, an acrylic polyol which is a polyol obtained by polymerizing an acrylic acid derivative monomer or a polyol obtained by copolymerizing an acrylic acid derivative monomer and other monomers is preferable. Among them, an acrylic polyol obtained by polymerizing an acrylic acid derivative monomer such as ethyl methacrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, hydroxybutyl methacrylate, or an acrylic polyol obtained by copolymerizing the acrylic acid derivative with another monomer such as styrene is preferable. Used. Considering the reactivity with the isocyanate compound and the compatibility with the trifunctional organosilane, the acrylic polyol preferably has a hydroxyl value in the range of 5 to 200 (KOHmg / g).

  The blending ratio of the acrylic polyol and the trifunctional organosilane is preferably in the range of 1/1 to 1000/1 by weight, and more preferably in the range of 2/1 to 100/1.

  Solvents for dissolution and dilution are not particularly limited as long as they can be dissolved and diluted. For example, esters such as ethyl acetate and butyl acetate, alcohols such as methanol, ethanol and isopropyl alcohol, ketones such as methyl ethyl ketone, Aromatic hydrocarbons such as toluene and xylene can be used alone or in any desired combination. When an aqueous solution such as hydrochloric acid is used to hydrolyze the trifunctional organosilane, it is preferable to use a solvent that is an arbitrary mixture of alcohols such as isopropyl alcohol and ethyl acetate that is a polar solvent as a cosolvent. .

  Isocyanate compounds are added to increase the adhesion to plastic substrates and inorganic oxides by urethane bonds formed by reaction with polyols such as acrylic polyols, and mainly act as crosslinking agents or curing agents. Specific examples of the isocyanate compound include monomers such as aromatic tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), aliphatic xylene diisocyanate (XDI), hexamethylene diisocyanate (HMDI), and isophorone diisocyanate (IPDI). And polymers or derivatives thereof, and one or more of them can be used.

  The mixing ratio of the acrylic polyol and the isocyanate compound is not particularly limited, but if the isocyanate compound is too small, curing may be poor, while if it is too much, blocking or the like occurs and there is a problem in processing. Therefore, the blending ratio of the acrylic polyol and the isocyanate compound is preferably 50 times or less of the NCO group derived from the isocyanate compound and the OH group derived from the acrylic polyol, and it is particularly preferable to blend the NCO group and the OH group in an equivalent amount. The mixing method is not particularly limited, and a known method can be used.

  The anchor coat layer is formed by preparing a composite solution in which trifunctional organosilane, polyol, and isocyanate compound are mixed at an arbitrary concentration, coating the substrate film, and drying and curing. Specifically, the primer agent for forming the primer layer is prepared by mixing a trifunctional organosilane and a polyol, adding a solvent and a diluent, diluting to an arbitrary concentration, and then mixing with an isocyanate compound. A trifunctional organosilane and polyol mixed in a solvent and previously reacted with the trifunctional organosilane and polyol may be prepared by adding a solvent and a diluent to dilute to an arbitrary concentration and then adding an isocyanate compound.

  For the anchor coat layer, various additives such as tertiary amines, imidazole derivatives, carboxylic acid metal salt compounds, quaternary ammonium salts, quaternary phosphonium salts and other curing accelerators, phenolic, sulfur-based, phosphites An antioxidant such as a system, a leveling agent, a flow regulator, a catalyst, a crosslinking reaction accelerator, a filler and the like may be added.

  The anchor coat layer is a base film using a known coating method such as an offset printing method, a gravure printing method, a silk screen printing method, or a known coating method such as a roll coating, a knife edge coating, or a gravure coating. After coating on top, it can be formed by drying the coating film, removing the solvent, and curing.

  Although the thickness of an anchor coat layer will not be specifically limited if a coating film can be formed uniformly, Generally it is preferable that it is the range of 0.01-2 micrometers. When the thickness is less than 0.01 μm, it is difficult to obtain a uniform coating film, and the adhesion may be lowered. On the other hand, when the thickness exceeds 2 μm, the coating film cannot be kept flexible because it is thick, and there is a possibility that the coating film may crack due to external factors, which is not preferable. A particularly preferred thickness is in the range of 0.05 to 0.5 μm.

  In the present invention, the surface of the polyamide-based resin base film (or anchor coat layer) on the side where the vapor deposition layer made of an inorganic compound is provided is treated with a reactive ion etching (RIE) mode plasma. preferable. The purpose of this treatment is to improve the adhesion when providing a vapor deposition layer made of an inorganic oxide.

  Argon, oxygen, nitrogen, and hydrogen can be used as gas species for performing the pretreatment by RIE. These gases may be used alone or in combination of two or more. Moreover, you may process continuously using two processor.

The processing conditions indicated by the processing speed, energy level, and the like are appropriately set according to the type of substrate, application, discharge device characteristics, and the like. However, the self-bias value of the plasma 200V or 2000V or less, Ed = Ed values defined in plasma density × treatment time is preferably set to 100V · s / m ² or more 10000V · s / m ² or less. Even if these conditions are slightly lower than the lower limit, a certain degree of adhesion can be exhibited, but the superiority is lower than that of untreated products. On the other hand, if these conditions are higher than the upper limit value, a strong treatment is applied too much, the surface of the base material is deteriorated, and the adhesiveness is lowered. The plasma gas and the mixing ratio thereof are appropriately set according to the application, the base material, and the apparatus characteristics because the flow rate differs between the introduction amount and the effective amount depending on the pump performance and the mounting position.

  In the present invention, the vapor-deposited layer made of an inorganic oxide is made of a vapor-deposited film of an inorganic oxide such as aluminum oxide, silicon oxide, tin oxide, magnesium oxide, or a mixture thereof, has transparency, oxygen, water vapor Any gas barrier property may be used. Aluminum oxide is preferable from the viewpoints of productivity and transparency. However, the vapor deposition layer in the present invention is not limited to these inorganic oxides, and any material that meets the above-described conditions can be used.

  The optimum value of the thickness of the vapor deposition layer varies depending on the type and configuration of the inorganic compound used, but is generally selected as appropriate within a range of 1 to 500 nm. If the film thickness is less than 1 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. On the other hand, if the film thickness exceeds 500 nm, flexibility cannot be maintained in the thin film, and the thin film may be cracked due to external factors such as bending and pulling after the film formation. is there.

  There are various methods for forming an inorganic oxide vapor-deposited layer on a base film (or anchor coat layer), and it can be formed by a normal vacuum vapor deposition method. A plating method, a plasma vapor deposition method (CVD), or the like can also be used. However, in view of productivity, the vacuum deposition method is the best at present. The heating means of the vacuum deposition apparatus by vacuum deposition is preferably an electron beam heating method, a resistance heating method, or an induction heating method. In order to improve the adhesion between the vapor deposition layer and the substrate film (or anchor coat layer) and the denseness of the vapor deposition layer, a plasma assist method or an ion beam assist method can also be used. In order to increase the transparency of the vapor deposition layer, reactive vapor deposition in which oxygen gas or the like is blown during vapor deposition may be performed.

  The gas barrier coating in the present invention is provided on a vapor deposition layer made of an inorganic oxide, and has the purpose of imparting high gas barrier properties comparable to an aluminum foil.

  The gas barrier coating is preferably a coating mainly comprising an aqueous solution or a water / alcohol mixed solution containing a water-soluble polymer and (a) at least one of a metal alkoxide or a hydrolyzate thereof and (b) tin chloride. Formed using an agent. More specifically, a solution in which a water-soluble polymer and tin chloride are dissolved in an aqueous (water or water / alcohol mixed) solvent, or a metal alkoxide or a metal alkoxide that has been previously subjected to a treatment such as hydrolysis is mixed. The deposited solution is coated on the vapor deposition layer and dried by heating. Each component contained in the coating agent will be described in more detail.

  The water-soluble polymer has a hydroxyl group, and examples thereof include ethylene-vinyl alcohol copolymer, polyvinyl alcohol, polyvinyl pyrrolidone, starch, methyl cellulose, carboxymethyl cellulose, and sodium alginate. In particular, when polyvinyl alcohol (hereinafter referred to as PVA) is used, the most excellent gas barrier coating can be obtained. PVA is generally obtained by saponifying polyvinyl acetate, and includes a so-called partially saponified PVA in which several tens percent of acetic acid groups remain to complete PVA in which only several percent of acetic acid groups remain, and is not particularly limited.

The tin chloride is stannous chloride (SnCl ₂ ), stannic chloride (SnCl ₄ ), or a mixture thereof, and may be anhydrous or hydrated.

The metal alkoxide is represented by the general formula M (OR) _n (where M is a metal atom such as Si, Ti, Al, and Zr, R is an alkyl group such as CH ₃ and C ₂ H ₅ ), and tetraethoxysilane [ Si (OC ₂ H ₅ ) ₄ ], triisopropoxy aluminum [Al (OC ₃ H ₇ ) ₃ ] and the like. Tetraethoxysilane and triisopropoxyaluminum are preferred because they are relatively stable in aqueous solvents after hydrolysis.

  A coating agent is prepared by combining each of the above components alone or in combination. Moreover, well-known additives, such as an isocyanate compound, a silane coupling agent, a dispersing agent, a stabilizer, a viscosity modifier, a coloring agent, can be added to a coating agent in the range which does not impair gas barrier property. Of these, the isocyanate compound preferably has two or more isocyanate groups (NCO groups) in the molecule, and monomers composed of aliphatic isocyanate compounds such as xylylene diisocyanate (XDI) and isophorone diisocyanate (IPDI), these And polymers thereof and their derivatives.

The gas barrier coating is more preferably a water-soluble polymer having a hydroxyl group described above, (a) at least one of a metal alkoxide or a hydrolyzate thereof and (b) tin chloride, and a general formula (R ₂ Si (OR ₁ ) ₃ ) _n (wherein R ₁ is selected from the group consisting of CH ₃ , C ₂ H ₅ and C ₂ H ₄ OCH ₃ , and R ₂ is an organic functional group). A coating agent mainly composed of an aqueous solution or a water / alcohol mixed solution is applied and dried by heating. Each component contained in the coating agent will be described in more detail.

In the general formula (R ₂ Si (OR ₁ ) ₃ ) _n , the organic functional group (R ₂ ) is preferably a non-aqueous functional group such as vinyl, epoxy, methacryloxy, ureido, and isocyanate. Non-aqueous functional groups are advantageous in improving water resistance because the functional groups are hydrophobic.

When the compound represented by the general formula (R ₂ Si (OR ₁ ) ₃ ) _n is a multimer, a trimer is preferable. For example, the general formula (NCO-R ₄ Si (OR ₁ ) ₃ ) ₃ (however, , R ₄ is (CH ₂ ) _n , n is 1 or more), 1,3,5-tris (3-trialkoxysilylalkyl) isocyanurate. This is a condensate of 3-isocyanatoalkylalkoxysilane.

1,3,5-tris (3-trialkoxysilylalkyl) isocyanurate is not chemically reactive in the isocyanurate part, but is known to exhibit the same performance as the reaction due to the polarity of the nurate part. . Generally, it is known as an adhesion improver that is added to an adhesive or the like in the same manner as 3-isocyanate alkylalkoxysilane. Therefore, by adding 1,3,5-tris (3-trialkoxysilylalkyl) isocyanurate to a water-soluble polymer having a hydroxyl group together with Si (OR ₁ ) ₄ , the gas barrier laminated film is made of water based on hydrogen bonds. It can prevent swelling and improve water resistance. In addition, 3-isocyanatealkylalkoxysilane has high reactivity and low liquid stability. On the other hand, the nurate part is not water-soluble due to its polarity, but it can be easily dispersed in an aqueous solution and can keep the liquid viscosity stable, and its water resistance is equivalent to that of 3-isocyanatoalkylalkoxysilane. Further, the nurate part is not only water resistant, but also has difficulty in becoming a pore of a barrier containing a water-soluble polymer having Si (OR ₁ ) ₄ and a hydroxyl group due to its polarity.

  1,3,5-tris (3-trialkoxysilylalkyl) isocyanurate is produced by thermal condensation of 3-isocyanatopropylalkoxysilane, and may contain 3-isocyanatepropylalkoxysilane as a raw material. There is no particular problem. 1,3,5-tris (3-trialkoxysilylalkyl) isocyanurate is preferably 1,3,5-tris (3-trialkoxysilylpropyl) isocyanurate, and 1,3,5-tris (3-tris (3-tris) More preferred is methoxysilylpropyl) isocyanurate. In particular, methoxy groups have a high hydrolysis rate, and those containing propyl groups can be obtained at a relatively low cost. Therefore, 1,3,5-tris (3-trimethoxysilylpropyl) isocyanurate is practically advantageous.

The organic functional group R ₂ is preferably a 3-glycidoxypropyl group or a 2- (3,4 epoxycyclohexyl) group. Since these organic functional groups form hydrogen bonds with Si (OR ₁ ) ₄ and water-soluble polymers by hydrolysis, they are unlikely to become pores of the barrier, and can improve water resistance without impairing gas barrier properties. .

However, some epoxy-based silane compounds may have mutagenic properties. Further, when the organic functional group (R ₂ ) is vinyl or methacryloxy, it is necessary to irradiate ultraviolet rays or an electron beam in the production process, and there is a tendency to increase costs due to an increase in equipment and processes. When the organic functional group (R ₂ ) is ureido, there is a specific odor, and when it is an isocyanate, the reactivity is high and the pot life is short. For this reason, the silicon compound represented by the general formula (R ₂ Si (OR ₁ ) ₃ ) _n is more preferably 1,3,5-tris (3-trialkoxysilylalkyl) isocyanurate.

  As a method for applying the coating agent, conventionally known means such as a dipping method, a roll coating method, a screen printing method, a spray method and the like that are usually used can be used. The thickness of the coating film varies depending on the type of coating agent 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 0.01 to 50 μm.

  In the present invention, the surface of the above-described polyamide-based resin base film on which the deposited film is not provided (element ratio O obtained by measurement under measurement conditions of an X-ray source MgKα and an X-ray output of 100 W by X-ray photoelectron spectroscopy) For example, a printing layer may be laminated on the surface (oxygen) / C (carbon) of 0.16 to 0.26. The printing layer is formed for practical use as letters, patterns, etc. on packaging bags, and various types of conventionally used ink binder resins such as urethane, acrylic, nitrocellulose, rubber, and vinyl chloride. This is a layer composed of ink to which additives such as pigments, moisture-resistant pigments, plasticizers, drying agents, stabilizers and the like are added. As a method for forming the printing layer, for example, a known printing method such as an offset printing method, a gravure printing method, or a silk screen printing method, or a known coating method such as roll coating, knife edge coating, or gravure coating can be used. The thickness of the printing layer is preferably 0.1 to 2.0 μm.

  In the present invention, the heat seal layer acts as a heat adhesive layer when forming a molded body such as a bag as a packaging material. Materials constituting the heat seal layer include linear low density polyethylene, medium density polyethylene, high density polyethylene, and other polyethylenes and ethylene copolymers, polyvinyl alcohol, ethylene-vinyl alcohol copolymers, polypropylene and propylene copolymers. Film made of olefin resin such as polymer, film made of vinyl chloride resin such as polyvinyl chloride and its copolymer, film made of vinylidene chloride resin such as vinylidene chloride-vinyl chloride copolymer, polyethylene terephthalate, etc. A film made of a polyester resin, a film made of a fluorine resin such as polytetrafluoroethylene, and a film made of a polyamide resin such as nylon.

  These materials are preferably selected in consideration of the thickness of the heat seal layer. The thickness of the heat seal layer is preferably in the range of 10 to 200 μm. If the thickness is less than 10 μm, sufficient strength as a packaging material cannot be obtained. On the other hand, if the thickness exceeds 200 μm, it is economically disadvantageous.

  The heat seal layer is made of, for example, a polyurethane resin, an acrylic resin, a polyester resin, an epoxy resin, or an arbitrary adhesive made of a copolymer resin of these resins. It can be bonded by a melt extrusion lamination method or the like.

  When using the above-described transparent barrier film as an intermediate use of a packaging material having a three-layer structure, the surface on the side where the deposited film of the above-described polyamide-based resin base film is not provided via an adhesive (X by X-ray photoelectron spectroscopy) The element ratio O (oxygen) / C (carbon) obtained by measurement under the measurement conditions of the radiation source MgKα and the X-ray output of 100 W) is bonded to the outer plastic substrate. Can do.

  The gas barrier film of the present invention thus obtained is bonded to a packaging material, for example, miso, pickles, side dishes, baby food, boiled, konjac, chikuwa, rice cake, processed fishery products, meatballs, hamburger, Genghis Khan, ham , Sausages, other processed meat products, tea, coffee, tea, bonito, garlic kelp, potato chips, butter peanuts and other oil confectionery, rice crackers, biscuits, cookies, cakes, buns, castella, cheese, butter, cut rice cake, soup In addition to foods such as sauces, ramen, and wasabi, toothpaste, pet food, agricultural chemicals, fertilizers, infusion packs, semiconductor packaging, industrial packaging such as precision materials packaging, industrial materials packaging such as medical, electronic, chemical, machinery, etc. Widely used in various forms such as bags, lids, cups, tubes, standing bags, etc. Can.

  Hereinafter, the present invention will be described in more detail based on examples. However, the present invention is not limited to these examples, and may be implemented with appropriate modifications within a scope that can meet the gist of the present invention. All of which are within the scope of the present invention.

(Anchor coating formulation)
7 g of a solution (solid content 20 wt%) prepared by mixing and stirring 0.6 g of isocyanate propyltrimethoxysilane with 6 g of acrylic polyol, 1.5 g of an isocyanate resin (solid content 50 wt%) as a curing agent and a diluting solvent And stirred for 30 minutes to give a solid content of 2 wt%.

(Formulation of gas barrier coating)
(Liquid A): Tetraethoxysilane Si (OC ₂ H ₅ ) ₄ (hereinafter referred to as TEOS) 17.9 g and methanol 10 g were added 72.1 g of hydrochloric acid (0.1N), stirred for 30 minutes, and hydrolyzed solid. Hydrolysis solution of 5% (weight ratio SiO ₂ conversion).

  (Liquid B): Water / methanol alcohol = 95/5 (weight ratio) solution of 5% (weight ratio) of polyvinyl alcohol.

(C solution): Hydrochloric acid (1N) was gradually added to β- (3,4 epoxycyclohexyl) trimethoxysilane and isopropyl alcohol (IPA solution), stirred for 30 minutes, hydrolyzed, and then water / IPA = 1. / 1 Hydrolysis solution adjusted to a solid content of 5% (weight ratio R ₂ Si (OH) ₃ conversion) by hydrolysis with the solution.

(Liquid D): 1,3,5-tris (3-methoxysilylpropyl) isocyanurate diluted with water / IPA = 1/1 solution to a solid content of 5% (weight ratio R ₂ Si (OH) ₃ conversion) Prepared solution.

Component mixing ratio of gas barrier coating agent A: Solid SiO ₂ content (converted value) of TEOS,
B: PVA solid content,
C: R ₂ Si (OH) ₃ solid content (converted value) of β- (3,4 epoxy cyclohexyl) trimethoxysilane,
D: R ₂ Si (OH) ₃ solid content (converted value) of 1,3,5-tris (3-methoxysilylpropyl) isocyanurate.

All compounding ratios are solid weight ratios. The prepared barrier coating agents are the following three types.
Barrier coating agent 1 ... A / B = 60/40
Barrier coating agent 2 ... A / B / C = 70/20/10
Barrier coating agent 3 ... A / B / D = 70/20/10
[Example 1]
A biaxially stretched nylon Ny (manufactured by Unitika Ltd., ON) having a thickness of 15 μm and having one side untreated and subjected to corona treatment on one side was prepared as a base film. This base film was put into a DC magnetron discharge type low temperature plasma processing unit using titanium (Ti) as a cathode, the degree of vacuum was set to 1.5 × 10 ⁻⁵ Torr, and oxygen (O ₂ ) gas was introduced. The oxygen level in the unit is set to 5.0 × 10 ⁻³ to generate oxygen plasma, and the untreated surface of the Ny film is subjected to low-temperature plasma treatment at an output of 1000 W for 0.5 seconds, and the surface of the Ny film Modified.

[Analysis of Ny surface condition]
An X-ray photoelectron spectrometer (JPS-90MXV manufactured by JEOL Ltd.) is used as the analyzer, and the X-ray source is set to non-monochromated MgKα (1253.6 eV) and the output is set to 100 W (10 kV-10 mA). did.

The analysis results were as follows.
The element ratio O (oxygen) / C (carbon) of the untreated polyamide surface before modification is 0.158,
The element ratio O (oxygen) / C (carbon) of the modified polyamide O ₂ plasma treated surface is 0.258.

  The prescribed anchor coating agent is applied to the corona-treated surface opposite to the modified surface of the surface-modified Ny film by bar coating, dried by heating at 80 ° C., and an anchor having a thickness of 0.1 μm A coat layer was formed.

  On the surface of the anchor coat layer, aluminum was vapor-deposited by an electron beam heating method in a vacuum vapor deposition machine, adjusted to a predetermined film composition while introducing oxygen gas, and an aluminum oxide vapor deposition layer having a thickness of 150 mm was formed.

  The prescribed barrier coating agent 1 is applied to the surface of the aluminum oxide vapor deposition layer with a bar coater and dried at 120 ° C. for 1 minute with a dryer to form a gas barrier film having a film thickness of about 0.3 μm. A film was obtained.

[Oxygen permeability evaluation]
According to JIS-K7126B, it measured with the oxygen permeability measuring apparatus ("OX-TRAN2 / 20" made by Modern Controls) on the measurement conditions of temperature 30 degreeC and humidity 70% RH. As a result, the oxygen permeability was 0.22 (cc / m ² / day / atm).

  Further, white ink (manufactured by Toyo Ink Manufacturing Co., Ltd., New LP Super) was applied to the oxygen plasma treated surface of the transparent gas barrier film with a bar coater.

[Ink adhesion evaluation]
Ink adhesion was evaluated by peeling the cellophane tape. As a result, no ink was removed.

Next, A515 / A50 (manufactured by Mitsui Takeda Chemical Co., Ltd.) was applied as an adhesive at a coating amount of 3.5 g / m ² on the gas barrier film opposite to the printed layer of the printed gas barrier film. Then, after laminating so that a corona discharge treated surface of 80 μm thick non-stretched polypropylene (CPP) with corona discharge treatment on one side was laminated, it was aged at 50 ° C. for 5 days, and a transparent barrier film A barrier packaging material using was obtained. A simplified configuration of the barrier packaging material is as follows.
White ink / plasma treatment / O-Ny 15 μm (corona-treated surface) / anchor coat / deposition film / barrier coat / adhesive / CPP 80 μm.

[Evaluation of laminate strength]
The laminate strength was measured with “Tensilon” manufactured by Orientec Co., Ltd. under measurement conditions in which the test piece was 15 mm wide, the peel angle was T-shaped, and the peel rate was 300 mm / min. As a result, the laminate strength was 8.0 (N / 15 mm).

[Example 2]
A transparent barrier film is produced in the same manner as in Example 1 except that the untreated surface of the Ny film is subjected to low-temperature plasma treatment using carbon dioxide gas, and the Ny film surface is modified. Obtained.

[Example 3]
A transparent barrier was applied in the same manner as in Example 1 except that the untreated surface of the Ny film was subjected to low temperature plasma treatment using a mixed gas of oxygen / argon (molar ratio 80/20) to modify the Ny film surface. A film was produced and a barrier packaging material was obtained.

[Example 4]
A transparent barrier film was produced in the same manner as in Example 1 except that the untreated surface of the Ny film was subjected to atmospheric pressure plasma treatment in the atmospheric state to modify the Ny film surface, and further a barrier packaging material was obtained. .

[Example 5]
The corona-treated surface opposite to the modified surface of the surface-modified Ny film was subjected to argon / oxygen (molar ratio 80 / 20) A RIE treatment was performed using a mixed gas, and a transparent barrier film was produced in the same manner as in Example 1 except that an aluminum oxide vapor deposition film was provided on the RIE treatment surface, and a barrier packaging material was obtained.

[Example 6]
A transparent barrier film was produced in the same manner as in Example 1 except that the barrier coating agent 2 was used as the barrier coating agent, and a barrier packaging material was obtained.

[Example 7]
A transparent barrier film was produced in the same manner as in Example 1 except that the barrier coating agent 3 was used as the barrier coating agent, and a barrier packaging material was obtained.

[Example 8]
The white ink used in Example 1 was applied to the corona-treated surface of polyethylene terephthalate PET (H100C manufactured by Mitsubishi Polyester) having a thickness of 12 μm, and the adhesive used in Example 1 was applied to this ink surface at 3.5 g / m ² . A barrier packaging material was obtained in the same manner as in Example 1, except that the transparent gas barrier film of Example 1 was bonded together in an application amount. A simplified configuration of the barrier packaging material is as follows.
PET 12 μm / white ink / adhesive / plasma treatment / O-Ny 15 μm (corona-treated surface) / anchor coat / deposited film / barrier coat / adhesive / CPP 80 μm
[Comparative Example 1]
A transparent barrier film was produced in the same manner as in Example 1 except that the low-temperature plasma treatment was not performed on the untreated surface of the Ny film, and a barrier packaging material was obtained.

[Comparative Example 2]
A transparent barrier film was produced in the same manner as in Example 8 except that the low-temperature plasma treatment was not performed on the untreated surface of the Ny film, and a barrier packaging material was obtained.

The evaluation results of Examples 1 to 8 and Comparative Examples 1 and 2 are summarized in Table 1.
The transparent gas barrier films of Examples 1 to 7 satisfying all the requirements of the present invention were excellent in ink adhesion and exhibited very low oxygen permeability. Moreover, the packaging material using these transparent gas barrier films had sufficient laminate strength. On the other hand, the transparent gas barrier film of Comparative Example 1 that deviates from the requirements of the present invention has poor ink adhesion, and a phenomenon in which ink is removed occurs.

Similarly, the packaging material of Example 8 that satisfies all the requirements of the present invention provides sufficient laminate strength between the PET / ink and the transparent gas barrier film, whereas the packaging of Comparative Example 2 that deviates from the requirements of the present invention. The material was not suitable as a packaging material because sufficient laminate strength was not obtained.

Sectional drawing of the transparent gas barrier film which concerns on one Embodiment of this invention. Sectional drawing of the packaging material which concerns on other embodiment of this invention. Sectional drawing of the packaging material which concerns on other embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Polyamide-type resin base film, 1a ... Outermost layer side surface, 1b ... Deposition layer side surface, 2 ... Anchor coat layer, 3 ... Deposition layer, 4 ... Gas barrier film, 10 ... Transparent gas barrier film, 11 ... Print layer, 12 ... adhesive, 13 ... heat seal layer, 14 ... plastic film substrate.

Claims (9)

  In the barrier film in which a vapor deposition layer made of an inorganic compound is provided on one side of the polyamide resin base film, the surface on the side where the vapor deposition film of the polyamide resin base film is not provided is an X-ray source by X-ray photoelectron spectroscopy. A barrier film, wherein an element ratio O (oxygen) / C (carbon) obtained by measurement under measurement conditions of MgKα and an X-ray output of 100 W is 0.16 to 0.26.   The barrier film according to claim 1, wherein an anchor coat resin layer is provided between the polyamide-based resin base film and the vapor deposition layer made of the inorganic compound. The anchor coat layer is an acrylic polyol, an isocyanate compound, and a general formula R′Si (OR) ₃ (R ′ is an alkyl group, a vinyl group, a glycidoxypropyl group, an amino group, an isocyanate group, and a sulfoxide group. The barrier film according to claim 2, comprising a composition containing a trifunctional organosilane selected from the group consisting of R and an alkyl group, or a hydrolyzate thereof.   Reactive ion etching using a gas selected from the group consisting of argon, nitrogen, oxygen and hydrogen and a mixed gas thereof on the surface of the polyamide-based resin base film on the side where the vapor deposition layer made of the inorganic compound is provided ( The barrier film according to any one of claims 1 to 3, wherein treatment with plasma in an RIE mode is performed.   The barrier film according to any one of claims 1 to 4, wherein a gas barrier coating is provided on a surface of the deposited film.   A coating agent mainly comprising an aqueous solution or a water / alcohol mixed solution, wherein the gas barrier film comprises a water-soluble polymer and (a) at least one of a metal alkoxide or a hydrolyzate thereof and (b) tin chloride. The barrier film according to claim 5, wherein the barrier film is applied and dried by heating. The gas barrier coating comprises a water-soluble polymer, (a) at least one of metal alkoxide or a hydrolyzate thereof, and (b) tin chloride, and a general formula (R ₂ Si (OR ₁ ) ₃ ) _n (wherein R ₁ is selected from the group consisting of CH ₃ , C ₂ H ₅ and C ₂ H ₄ OCH ₃ , and R ₂ is an organic functional group). The barrier film according to claim 5, wherein the coating film is formed by applying a coating agent containing a main component and heating and drying.   A packaging material, wherein a printed layer is provided on a surface of the polyamide-based resin base film that constitutes the barrier film according to any one of claims 1 to 7, on a surface on which a deposited film is not provided.   A packaging material, wherein a plastic film substrate and a heat seal layer are provided on both surfaces of the barrier film according to any one of claims 1 to 7 via an adhesive.

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