JP2005153306A - Transparent gas barrier film laminate having retorting property - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a transparent gas barrier film laminate of high practicality excellent in transparency and having high-degree gas barrier properties and sterilization treatment durability corresponding to those of metal foil. <P>SOLUTION: This transparent gas barrier film laminate having retorting properties is constituted by successively laminating a primer layer 2 comprising a composite of a acrylpolyol, an isocyanate compound and a silane coupling agent, a vapor deposition thin film layer 3 comprising an inorganic oxide, a gas barrier film layer 4 formed by heating and drying a coating layer comprising an aqueous solution or a water/alcohol mixed solution containing a water soluble polymer and at least one kind of a metal alkoxide or its hydrolyzate, a two-pack type polyester type curable adhesive layer 5 containing a styrene/maleic acid anhydride copolymer and a heat-sealable layer 8 comprising a polyolefinic resin at least on one side of a plastic base material 1 in this order. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a packaging field requiring boil sterilization, retort sterilization, and the like, and more particularly to a transparent gas barrier film laminate having retort suitability for packaging used mainly in packaging fields such as foods, non-foods and pharmaceuticals.

  In recent years, packaging materials used for packaging foods, non-foods, pharmaceuticals, etc. contain oxygen, water vapor, and other contents that permeate the packaging material in order to suppress the alteration of the contents and maintain their functions and properties. It is necessary to prevent the influence of the gas to be altered, and it is required to have a gas barrier property and the like for blocking these. Therefore, conventionally, a packaging material using a metal foil such as aluminum as a gas barrier layer, which is less affected by temperature and humidity, has been generally used.

  However, packaging materials using metal foils such as aluminum are not affected by temperature and humidity and have excellent gas barrier properties. However, the contents cannot be confirmed through the packaging material. Had problems such as having to be treated as non-combustible material and being unable to use a metal detector during inspection.

Therefore, as a packaging material that has overcome these disadvantages, for example, a vacuum deposition method, a sputtering method, etc. on a polymer film as described in US Pat. No. 3,442,686, Japanese Patent Publication No. 63-28017, etc. A film in which a deposited film of an inorganic oxide such as silicon oxide or aluminum oxide is formed by a forming means has been developed. These vapor-deposited films are known to have transparency and gas barrier properties such as oxygen and water vapor, and are suitable as packaging materials having transparency and gas barrier properties that cannot be obtained with metal foil or the like. .
JP 11-129384 A

  However, even a film suitable for the packaging material described above is rarely used as a vapor deposition film alone as a packaging container or packaging material. In other words, the packaging body is completed through various processes such as printing on the surface of the deposited film as a post-processing after the deposition, bonding with a film, etc., and shape processing on a packaging body such as a container. . In particular, since packaging materials used for boil sterilization, retort sterilization, and the like are sterilized through various processes, careful attention must be paid to the design of the packaging materials.

Therefore, after the bag was bonded to the sealant film using the above-described vapor deposition film, the contents were filled and an attempt was made to boil sterilization or retort sterilization. There are problems such as failure, gas barrier properties from that portion, and deterioration of contents. .
That is, as conditions used as a packaging material in such a case, the transparency that allows the contents to be directly seen through, the high gas barrier property that blocks the gas that affects the contents, and the boil sterilization In addition, there is no need to have a gas barrier property deterioration after sterilization or retort, and resistance to sterilization treatment that does not cause peeling or the like. At present, no packaging material that satisfies these requirements has been found.

Therefore, an object of the present invention is to provide a highly practical film laminate that is excellent in transparency and has high gas barrier properties and sterilization resistance similar to metal foils.

  The present invention is for achieving the above object, and the invention according to claim 1 of the present invention comprises, as shown in FIG. 1, an acrylic polyol and an acrylic polyol on at least one surface of a transparent plastic substrate 1 made of a polyester resin. An aqueous solution or water containing a primer layer 2 made of a composite of an isocyanate compound and a silane coupling agent, a deposited thin film layer 3 made of an inorganic oxide, a water-soluble polymer and one or more metal alkoxides or hydrolysates thereof. / Gas barrier coating layer 4 formed by applying an alcohol mixed solution and drying by heating, polyester-based two-component curable adhesive layer 5 containing a styrene-maleic anhydride copolymer, heat-seal layer 8 made of polyolefin resin, Is a transparent gas barrier film laminate having retort suitability characterized by being sequentially laminated in this order.

  As shown in FIG. 2, the invention according to claim 2 of the present invention is a primer comprising a composite of an acrylic polyol, an isocyanate compound and a silane coupling agent on at least one surface of a transparent plastic substrate 1 made of a polyester resin. Gas barrier properties obtained by applying a layer 2, an evaporated thin film layer 3 made of an inorganic oxide, an aqueous solution containing a water-soluble polymer and at least one metal alkoxide or a hydrolyzate thereof, or a water / alcohol mixed solution and drying by heating. Coating layer 4, polyester-based two-part curable first adhesive layer 5 containing a styrene maleic anhydride copolymer, intermediate layer 6 made of a stretched nylon film, and a polyester system containing a styrene-maleic anhydride copolymer The two-component curable second adhesive layer 7 and the heat seal layer 8 made of polyolefin resin are sequentially laminated in this order. It is transparent gas barrier film laminate having a retort suitability, characterized in that there.

  According to a third aspect of the present invention, in the transparent gas barrier film laminate having retort suitability according to the first aspect, the polyester-based two-component curable adhesive layer 5 is made of 10 styrene maleic anhydride copolymer. It is the transparent gas barrier film laminated body which has retort suitability characterized by including in the ratio of-1weight%.

  The invention according to claim 4 of the present invention is the transparent gas barrier film laminate having retort suitability according to claim 1, wherein the glass transition point (Tg) of the polyester resin as the main component in the polyester-based two-component curable adhesive layer. Is a transparent gas barrier film laminate having retort suitability characterized by being 10 ° C. or lower.

  According to claim 5 of the present invention, in the transparent gas barrier film laminate having retort suitability according to claim 2, at least the first adhesive layer 5, or the first adhesive layer 5 and the second adhesive. A transparent gas barrier film laminate having retort suitability, wherein the layer 7 is a polyester-based two-component curable adhesive and contains a styrene maleic anhydride copolymer in a proportion of 10 to 1% by weight. is there.

  According to a sixth aspect of the present invention, in the transparent gas barrier film laminate having retort suitability according to the second aspect, in at least the first adhesive layer or the first adhesive layer and the second adhesive layer. It is a transparent gas barrier film laminate having retort suitability, characterized in that the glass transition point (Tg) of a polyester resin as a main ingredient is 10 ° C. or lower.

  The invention according to claim 7 of the present invention is the transparent gas barrier film laminate having retort suitability according to any one of claims 1 to 6, wherein the silane coupling agent is an acrylic polyol hydroxyl group or an isocyanate compound isocyanate. A transparent gas barrier film laminate having retort suitability, characterized by having an organic functional group that reacts with at least one of the groups.

  The invention according to claim 8 of the present invention is the transparent gas barrier film laminate having retort suitability according to claim 7, wherein the organic functional group contained in the silane coupling agent is an isocyanate group, an epoxy group, or an amino group. It is a transparent gas barrier film laminate having retort suitability characterized by being.

  The invention according to claim 9 of the present invention is the transparent gas barrier film laminate having retort suitability according to any one of claims 1 to 8, wherein the inorganic oxide is aluminum oxide, silicon oxide, or a material thereof. It is a transparent gas barrier film laminate having retort suitability, which is a mixture.

  The invention according to claim 10 of the present invention is the transparent gas barrier film laminate having retort suitability according to any one of claims 1 to 9, wherein the metal alkoxide is tetraethoxysilane, triisopropoxyaluminum, or It is a transparent gas barrier film laminate having retort suitability characterized by being a mixture thereof.

  The invention according to claim 11 of the present invention is the transparent gas barrier film laminate having retort suitability according to any one of claims 1 to 10, wherein the water-soluble polymer is polyvinyl alcohol. It is a transparent gas barrier film laminate having retort suitability.

  According to the transparent gas barrier film laminate having retort suitability according to claim 1 of the present invention, as shown in FIG. 1, transparency, heat resistance and dimensional stability are provided on at least one surface of a transparent plastic substrate 1 made of polyester resin. After providing the adhesion primer layer 2 having excellent properties, it has excellent heat resistance including 10% by weight to 1% by weight of a vapor-deposited thin film layer 3 / gas barrier coating layer 4 / styrene maleic anhydride copolymer as a transparent gas barrier layer. Heat of adhesive layer 5 / polyolefin resin having a glass transition point (Tg) of the polyester resin of the main component in the two-part curable adhesive, which is a two-part curable adhesive. Since it is composed of a seal layer 8 (sealant layer), it has a gas barrier property similar to that of a metal foil that has been desired so far, and is also boiled. After various sterilization processes, such as bacteria and retort sterilization is high laminate practical capable of suppressing the deterioration of the barrier properties and the like can be obtained.

  Moreover, according to the transparent gas barrier film laminate having retort suitability according to claim 2 of the present invention, as shown in FIG. 2, at least one side of the transparent plastic substrate 1 made of polyester resin has transparency and heat resistance, and After the adhesion primer layer 2 having excellent dimensional stability is provided, the heat resistance includes 10% by weight to 1% by weight of a vapor-deposited thin film layer 3 / gas barrier coating layer 4 / styrene maleic anhydride copolymer as a transparent gas barrier layer. The first adhesive layer 5 having a glass transition point (Tg) of the polyester resin as the main component in the two-component curable adhesive, which is excellent in the two-component curable adhesive, and stretched Nylon film intermediate layer 6 / polyester-based two-component curable second adhesive layer 7 containing 10% by weight to 1% by weight of styrene maleic anhydride copolymer 7% Since it is composed of a heat-seal layer 8 (sealant layer) made of polyolefin resin, it has a gas barrier property similar to that of metal foils that could not be obtained so far, and it is also a barrier after various sterilization treatments such as boil sterilization and retort sterilization. A highly practical laminate capable of suppressing deterioration of properties and the like is obtained.

  Therefore, the gas barrier film laminate of the present invention is excellent in transparency, can confirm the contents through the packaging material, and has a versatile gas barrier property similar to that of metal foil even after boil sterilization or retort sterilization. A certain packaging material is obtained and can be widely used in the packaging field.

  The present invention will be described in more detail with reference to the drawings. FIG. 1 is a side sectional view for explaining an embodiment of a transparent transparent barrier film laminate having retort aptitude according to claim 1 of the present invention, and FIG. 2 is a retort aptitude gas retort aptitude according to claim 2 of the present invention. It is a sectional side view explaining one Embodiment of a transparent sub barrier film laminated body.

  The transparent gas barrier film laminate having retort suitability according to claim 1 of the present invention has an acrylic polyol and an isocyanate compound on at least one surface of a transparent plastic substrate 1 made of a polyester resin, as shown in a side sectional view of FIG. And an aqueous solution or water / alcohol containing a primer layer 2 made of a composite of a silane coupling agent, a deposited thin film layer 3 made of an inorganic oxide, a water-soluble polymer and one or more metal alkoxides or hydrolysates thereof. A gas barrier coating layer 4 formed by applying a mixed solution and drying by heating is sequentially laminated in this order, and a polyester-based two-component curing type containing a styrene-maleic anhydride copolymer on the gas barrier coating layer 4. A heat seal layer 8 made of a polyolefin-based resin is laminated via an adhesive layer 5.

  The plastic substrate 1 of the transparent gas barrier film laminate shown in FIG. 1 is a film substrate made of a saturated polyester-based transparent plastic film such as polyethylene terephthalate (PET) or polyethylene naphthalate (PEN). On at least one side of 1, a primer layer 2 made of a composite containing an acrylic polyol, an isocyanate compound, and a silane coupling agent, and a deposited thin film layer 3 made of an inorganic oxide having a thickness of 5 to 100 nm are coated. A polyester-based two-component curable adhesive having excellent heat resistance, including a gas barrier coating layer 4 and a styrene-maleic anhydride copolymer, the styrene-maleic anhydride copolymer in a proportion of 10 to 1% by weight. Or 10 to 1% by weight of styrene maleic anhydride copolymer And a polyester two-component curable adhesive layer 5 having a glass transition point (Tg) of the main component polyester resin in the two-component curable adhesive and a heat seal having a thickness of 15 to 200 μm. Layer 8 (sealant layer) is sequentially laminated in this order. In addition, the said plastic substrate 1, the primer layer 2, and the vapor deposition thin film layer 3 which consists of inorganic oxides can use the gas barrier laminated film (for example, GL film: Toppan Printing Co., Ltd. product) provided with the gas barrier vapor deposition layer.

  The transparent gas barrier film laminate having retort suitability according to claim 2 of the present invention has an acrylic polyol, an isocyanate compound, and at least one surface of a plastic substrate 1 made of a polyester resin, as shown in a side sectional view of FIG. Primer layer 2 composed of a composite with a silane coupling agent, vapor-deposited thin film layer 3 composed of an inorganic oxide, an aqueous solution or water / alcohol mixture containing a water-soluble polymer and one or more metal alkoxides or hydrolysates thereof. A gas barrier coating layer 4 formed by applying a solution and heating and drying is sequentially laminated in this order, and a polyester-based two-component curable type containing a styrene-maleic anhydride copolymer is formed on the gas barrier coating layer 4 in this order. An intermediate layer 6 made of a stretched nylon film is laminated through one adhesive layer 5, and styrene is formed on the intermediate layer 6. Through a two-component curable second adhesive layer 7 of a polyester containing the water-maleic acid copolymer, heat-seal layer 8 by the polyolefin resin is one that are sequentially stacked.

The plastic substrate 1 of the transparent gas barrier film laminate shown in FIG. 2 is a film substrate made of a saturated polyester-based transparent plastic film such as polyethylene terephthalate (PET) or polyethylene naphthalate (PEN). On at least one side of the film, a primer layer 2 made of a composite containing an acrylic polyol, an isocyanate compound, and a silane coupling agent, and a deposited thin film layer 3 made of an inorganic oxide having a thickness of 5 to 100 nm were coated. A polyester-based two-component curable adhesive containing a gas barrier coating layer 4 and a styrene-maleic anhydride copolymer and having excellent heat resistance, and containing 10% by weight to 1% by weight of a styrene-maleic anhydride copolymer Or 10% by weight to 1% by weight of styrene maleic anhydride copolymer %, And the glass transition point (Tg) of the main polyester resin in the two-component curable adhesive is 10 ° C. or less, and the polyester-based two-component curable first adhesive layer 5 and the stretched nylon film intermediate layer 6 And a polyester-based two-component curable adhesive containing a styrene maleic anhydride copolymer and having excellent heat resistance, comprising 10% by weight to 1% by weight of a styrene maleic anhydride copolymer, or a styrene maleic anhydride A polyester-based two-component solution containing 10% by weight to 1% by weight of an acid copolymer and having a glass transition point (Tg) of a polyester resin as a main component of the two-component curable adhesive as required. A polyester two-component curable second adhesive layer 7 using a curable adhesive and a heat seal layer 8 (sealant layer) having a thickness of 15 to 200 μm are sequentially laminated in this order. Also in this case, the plastic substrate 1, the primer layer 2, and the vapor-deposited thin film layer 3 made of an inorganic oxide are gas barrier laminated films having a gas barrier vapor-deposited layer (for example, GL film: manufactured by Toppan Printing Co., Ltd.). Can be used.

  The plastic substrate 1 in the present invention (FIGS. 1 and 2) may be either stretched or unstretched, and preferably has mechanical strength and dimensional stability. Among these, a polyethylene terephthalate film or a polyamide film arbitrarily stretched in the biaxial direction is preferably used. Further, various known additives and stabilizers such as an antistatic agent, an anti-ultraviolet agent, a plasticizer, and a lubricant may be used on the surface of the substrate 1 opposite to the surface on which the vapor deposition layer is provided. good. In addition, in order to improve the adhesion to the thin film, the laminated surface side of the base material is subjected to any treatment such as corona treatment, low temperature plasma treatment, ion bombardment treatment, chemical treatment, solvent treatment as a pretreatment. Also good.

  The thickness of the plastic substrate 1 is not particularly limited, and a film obtained by laminating films having different properties in addition to a single film can be used in consideration of suitability as a packaging material. In view of workability when forming the primer layer 2, the vapor-deposited thin film layer 3 made of an inorganic oxide, the gas barrier coating layer 4, and the stress / moisture relaxation layer, a range of 3 to 200 μm is preferable for practical use. In particular, the thickness is preferably 6 to 30 μm.

  In consideration of mass productivity, it is desirable to use a long continuous film so that the layers can be formed continuously.

  The primer layer 2 in the present invention (FIGS. 1 and 2) is provided on a base material 1 made of a plastic material, and improves the adhesion between the base material 1 and the vapor-deposited thin film layer 3 made of an inorganic oxide. It is a layer provided in order to prevent the peeling of the deposited thin film layer 3 after various sterilization treatments such as sterilization and retort sterilization.

  As a result of intensive studies, the present inventors have found that it is a composition with an acrylic polyol, an isocyanate compound, a silane coupling agent and the like that can be used as the primer layer 2 in the present invention in order to achieve the above object. It was.

Furthermore, if it demonstrates in detail about the composition which comprises the said primer layer 2, the acrylic polyol as a composition which comprises the primer layer 2 used by this invention will be obtained by polymerizing an acrylic acid derivative monomer. Among polymer compounds or polymer compounds obtained by copolymerizing acrylic acid derivative monomers and other monomers, those having a hydroxyl group at the terminal and reacted with the isocyanate group of the isocyanate compound added later is there. Among these, those obtained by polymerizing acrylic acid derivative monomers such as ethyl methacrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, and hydroxybutyl methacrylate alone, and acrylic polyols obtained by copolymerizing with other monomers such as styrene are preferably used. In consideration of the reactivity with the isocyanate compound, the hydroxyl value is preferably between 5 and 200 (KOHmg / g).

  Further, the isocyanate compound as a composition constituting the primer layer 2 used in the present invention has an adhesive property to the plastic substrate 1 and the vapor-deposited thin film layer 3 made of an inorganic oxide by a urethane bond formed by reaction with an acrylic polyol. It is added in order to increase the viscosity, and mainly acts as a crosslinking agent or a curing agent. In order to achieve this, the isocyanate compounds include aromatic tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), aliphatic xylene diisocyanate (XDI), hexadiisocyanate (HMDI), isophorone diisocyanate (IPDI). And the like, and polymers and derivatives thereof. These are used alone or as a mixture.

  The blending ratio of the acrylic polyol and the isocyanate compound is not particularly limited. However, if the isocyanate compound is too small, the curing may be poor, and if it is too much, blocking or the like occurs, resulting in processing problems. There is. Therefore, the mixing ratio of the acrylic polyol and the isocyanate compound is preferably that the isocyanate group derived from the isocyanate compound is 50 times or less of the hydroxyl group derived from the acrylic polyol. Particularly preferred is a case where an isocyanate group and a hydroxyl group are blended in equal amounts. As a mixing method, a known method can be used and is not particularly limited.

  In addition, as the silane coupling agent as a composition constituting the primer layer 2 used in the present invention, a silane coupling agent containing an arbitrary organic functional group can be used, for example, ethyltrimethoxysilane, vinyltril. Silane coupling agents such as methoxysilane, γ-chloropropylmethyldimethoxysilane, γ-chloropropyltrimethoxysilane, glycidoxypropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropylmethyldimethoxysilane Alternatively, one or more of the hydrolysates can be used.

  Further, among these silane coupling agents, those having a functional group that reacts with a hydroxyl group of an acrylic 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, γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, N-β- (aminoethyl)- Those containing amino groups such as γ-aminopropyltriethoxysilane and γ-phenylaminopropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane and β- (3,4-epoxycyclohexyl) ethyltri Those containing an epoxy group such as methoxysilane can be used alone or in a mixture of two or more. These silane coupling agents contain a functional group in which an organic functional group present at one end exhibits an interaction in a composite composed of an acrylic polyol and an isocyanate compound, or reacts with a hydroxyl group of an acrylic polyol or an isocyanate group of an isocyanate compound. By providing a covalent bond by using a silane coupling agent, a stronger primer layer is formed, and the silanol group generated by hydrolysis of the alkoxy group at the other end is a metal in inorganic oxide or inorganic oxidation. High adhesion with an inorganic oxide is expressed by strong interaction with a highly active hydroxyl group on the surface of the material, and the desired physical properties can be obtained. Therefore, you may use what hydrolyzed the said silane coupling agent with the metal alkoxide. Further, even if the alkoxy group of the silane coupling agent is a chloro group, an acetoxy group, etc., there is no problem, and these alkoxy groups, chloro groups, acetoxy groups, etc. are hydrolyzed to form silanol groups. If present, it can be used in this composite.

The mixing ratio of the acrylic polyol and the silane coupling agent is 1/1 to 100 / weight ratio.
It is preferably in the range of 1, more preferably in the range of 2/1 to 50/1.

  The dissolving and diluting solvent is not particularly limited as long as it 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, A mixture of aromatic hydrocarbons such as toluene and xylene alone and arbitrarily can be used. However, since an aqueous solution such as hydrochloric acid or acetic acid may be used to hydrolyze the silane coupling agent, it is necessary to use a solvent in which isopropyl alcohol or the like and ethyl acetate that is a polar solvent are arbitrarily mixed as a co-solvent. More preferred.

In addition, when the silane coupling agent is blended, a reaction catalyst may be added to promote the reaction. Examples of the catalyst to be added include tin compounds such as tin chloride (SnCl ₂ , SnCl ₄ ), tin oxychloride (SnOHCl, Sn (OH) ₂ Cl ₂ ), and tin alkoxide from the viewpoint of reactivity and polymerization stability. It is possible to use. These catalysts may be added directly at the time of blending, or may be added after being dissolved in a solvent such as methanol.

  As a method for preparing a primer solution for forming a coating film of the composition in the present invention, a composite solution in which an acrylic polyol, an isocyanate compound, and a silane coupling agent are mixed at an arbitrary blending ratio is manufactured, and this is used as a base material 1. And coated. As a method for producing the composition solution, a silane coupling agent and an acrylic polyol are mixed, a solvent and a diluent are added, diluted to an arbitrary concentration, and then mixed with an isocyanate compound, or a composite solution is prepared in advance. A method in which a silane coupling agent is mixed in a solvent and then mixed with an acrylic polyol is added to a solvent and a diluent, diluted to an arbitrary concentration, and then an isocyanate compound is added to prepare a composite solution. is there.

  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, phosphite-based, etc. Antioxidants, leveling agents, flow regulators, catalysts, crosslinking reaction accelerators, fillers, and the like can be added as necessary.

  The thickness of the primer layer 2 is not particularly limited as long as a uniform coating film can be formed. However, the dry film thickness is generally preferably in the range of 0.01 to 2 μm. 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, if the thickness exceeds 2 μm, the coating film cannot be kept flexible because it is thick, and the coating film may be cracked due to external factors. The thickness of the primer layer 2 is particularly preferably in the range of 0.05 to 0.5 μm.

  As a method for forming the primer layer 2, for example, a known printing 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 can be used. . As drying conditions, generally used conditions are employed.

  The transparent gas barrier film laminate of the present invention (FIGS. 1 and 2) has a first layer, a second layer, which will be described later, as a result of intensive studies in order to maintain gas barrier properties and content resistance even after retorting. It is necessary to be composed of three third layers (the deposited thin film layer 3, the gas barrier coating layer 4, and the adhesive layer 5 shown in FIG. 1 or the first adhesive layer 5 shown in FIG. 2). Each layer forming the gas barrier layer in the present invention will be described in more detail.

First, the vapor deposition thin film layer 3 made of an inorganic oxide, which is a first layer for forming a gas barrier layer, will be described. The vapor-deposited thin film layer 3 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, and has transparency, such as oxygen and water vapor. Any layer having gas barrier properties may be used. Considering various sterilization resistances, it is more preferable to use aluminum oxide and silicon oxide among these. However, the vapor-deposited thin film layer 3 of the present invention is not limited to the inorganic oxide described above, and any material that meets the above conditions can be used.

  The optimum thickness of the vapor-deposited thin film layer 3 varies depending on the type and configuration of the inorganic compound to be used, but is generally preferably in the range of 5 to 300 nm, and the value is 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, the thin film cannot be kept flexible, and there is a problem because the thin film may be cracked due to external factors such as bending and pulling after the film formation. More preferably, it exists in the range of 10-150 nm.

  There are various methods for forming the vapor-deposited thin film layer 3 made of an inorganic oxide on a plastic substrate, and it can be formed by a normal vacuum vapor deposition method. In addition, other thin film forming methods such as a sputtering method, an ion plating method, and a plasma vapor deposition method (CVD) can also be used. However, considering productivity, the vacuum deposition method is the best at present. As a heating means of the vacuum evaporation method, it is preferable to use any one of an electron beam heating method, a resistance heating method, and an induction heating method, but the electron beam heating method should be used in consideration of the wide selection of evaporation materials. Is more preferable. Moreover, in order to improve the adhesiveness of the vapor deposition thin film layer 3 and the base material 1, and the denseness of the vapor deposition thin film layer 3, it is also possible to vapor-deposit using a plasma assist method or an ion beam assist method. In order to increase the transparency of the deposited film, it is possible to use reactive deposition in which various gases such as oxygen are blown during the deposition.

  Next, the gas barrier coating layer 4 that is the second layer for forming the gas barrier layer will be described. The gas barrier coating layer 4 is formed by using a coating agent mainly composed of an aqueous solution containing a water-soluble polymer and one or more metal alkoxides or a hydrolyzate thereof, or a water / alcohol mixed solution. For example, a solution obtained by mixing a water-soluble polymer dissolved in an aqueous (water or water / alcohol mixed) solvent with a metal alkoxide directly or previously hydrolyzed is used as a solution. This solution is formed by coating the deposited thin film layer 3 made of an inorganic oxide, which is a first gas barrier layer, and then drying by heating. Each component contained in the coating agent will be described in more detail.

  Examples of the water-soluble polymer used as a coating agent for forming the gas barrier coating layer 4 in the present invention include polyvinyl alcohol, polyvinyl pyrrolidone, starch, methyl cellulose, carboxymethyl cellulose, and sodium alginate. In particular, when polyvinyl alcohol (hereinafter referred to as PVA) is used for the coating agent of the present invention, the gas barrier property is most excellent, which is preferable. PVA here is generally obtained by saponifying polyvinyl acetate. As the PVA, for example, complete PVA in which only a few percent of acetic acid groups remain from so-called partially saponified PVA in which several tens of percent of acetate groups remain can be used. I do not care.

The metal alkoxide is a compound represented by a general formula, M (OR) _n (M: metal such as Si, Ti, Al, Zr, R: alkyl group such as R ₃ : CH ₃ , C ₂ H ₅ ). Specific examples include tetraethoxysilane [Si (OC ₂ H ₅ ) ₄ ], triisopropoxyaluminum [Al (O-2′-C ₃ H ₇ ) ₃ ], and among others, tetraethoxysilane and triisopropoxy. Aluminum is preferable because it is relatively stable in an aqueous solvent after hydrolysis.

  It is also possible to add known additives such as isocyanate compounds, silane coupling agents, or dispersants, stabilizers, viscosity modifiers, and colorants to the solution as long as the gas barrier properties are not impaired. is there.

  As a coating method of the coating agent for forming the gas barrier film layer 4, conventionally known methods such as a dipping method, a roll coating method, a screen printing method, a spray method, a gravure printing method and the like can be used.

  The optimum thickness of the gas barrier coating layer 4 varies depending on the type of coating agent, the processing machine, and the processing conditions, and is not particularly limited. However, when the thickness after drying is 0.01 μm or less, a uniform coating film cannot be obtained, and sufficient gas barrier properties may not be obtained. On the other hand, when the thickness exceeds 50 μm, cracks are likely to occur in the film, which may be a problem. It is preferably in the range of 0.01 to 50 μm, more preferably in the range of 0.1 to 10 μm.

  As shown in FIG. 1, a transparent gas barrier film laminate having retort suitability according to claim 1 of the present invention has a styrene / maleic anhydride copolymer on the gas barrier coating layer 4 laminated on one side of the plastic substrate 1. A heat seal layer 8 (sealant layer) is laminated and laminated through an adhesive layer 5 of a polyester-based two-component curable adhesive containing a polymer in a range of 10 to 1% by weight. As a lamination method, lamination can be performed by a known method such as a dry lamination method in which a two-component curable polyester adhesive is used.

  Further, the transparent gas barrier film laminate having retort suitability according to claim 2 of the present invention has an intermediate layer of stretched nylon film on the gas barrier coating layer 4 laminated on one side of the plastic substrate 1, as shown in FIG. Layer 6 is a first adhesive layer 5 made of a polyester two-component curable adhesive containing styrene / maleic anhydride copolymer in the range of 10 to 1% by weight (same as adhesive layer 5 shown in FIG. 1). Is laminated and laminated. As a lamination method, lamination can be performed by a known method such as a dry lamination method in which a two-component curable polyester adhesive is used.

  The adhesive layer 5 (see FIG. 1) or the first adhesive layer 5 (see FIG. 2) made of the polyester-based two-component curable adhesive maintains the gas barrier function of the first and second layers. In order to improve content resistance, at least 10 to 1% by weight of a styrene / maleic anhydride copolymer is contained.

  In addition, the adhesive layer 5 or the first adhesive layer 5 is subjected to stress from the sealant layer 8 or the intermediate layer 6 that occurs during various sterilization treatments such as boil sterilization and retort sterilization, which are considered to be a factor of barrier lowering. It has an object and function as a protective layer that relaxes absorption and protects the inorganic compound vapor-deposited thin film layer 3 as the first layer forming the gas barrier layer and the gas barrier film layer 4 as the second layer. .

  The polyester adhesive layer 5 or the first adhesive layer 5 containing the styrene maleic anhydride copolymer as the third layer forming the gas barrier layer will be described in more detail. Styrene maleic anhydride copolymer Is a copolymer obtained by copolymerizing styrene and maleic anhydride and purified by a known technique, and the copolymerization ratio and the like are not particularly limited as long as the above object can be achieved. By including the copolymer, the adhesion with the gas barrier coating layer 4 as the second gas barrier layer is improved, and the dimensional stability during high temperature sterilization is further improved. It is possible to absorb and relieve stress and the like applied to the vapor deposition thin film layer 3 as the gas barrier layer and the gas barrier film layer 4 as the second gas barrier layer.

  Further, the copolymer is added to a known two-component curable polyester-based adhesive, and a layer other than a protective layer for the vapor-deposited thin film layer 3 as the first gas barrier layer and the gas barrier coating layer 4 as the second gas barrier layer. It is also possible to use in a form to which the above functions are added. As a coating method, when the adhesive layer 5 (see FIG. 1) or the first adhesive layer 5 (see FIG. 2) is used as an overcoat layer, when used as an adhesive layer, when used as an ink layer, etc. Although the method differs depending on the required function, any of them can be formed by a known coating method. For example, when the layer 5 is used as an adhesive layer, the gas barrier coating layer 4 is formed and then formed separately in a separate machine, or after the gas barrier coating layer 4 is applied, the layer 5 is formed in-line. Although it may be provided, it is appropriate to provide the gas barrier coating layer 4 in-line after coating. As the coating method, a known method such as a gravure printing method can be used.

  The thickness of the polyester-based two-component curable adhesive layer 5 (or the first adhesive layer 5) varies depending on the type, function, and application used, but absorbs the effects of stress, etc.・ There is no particular limitation as long as it can be mitigated. However, if the thickness is less than 0.1 μm, it is difficult to obtain a uniform coating film, and the relaxation effect may be lowered, which is not preferable. If it is thick, the relaxation effect is sufficient, but there is a problem of cost. In general, the dry thickness is preferably in the range of 0.1 to 10 μm, more preferably in the range of 0.3 to 5 μm.

  Furthermore, for example, an information printing layer of a packaging container may be provided on the surface of the polyester-based two-component curable adhesive layer 5 (or the first adhesive layer 5) as another layer. For example, the printed layer is formed for practical use as a packaging bag or the like. For example, additives such as various pigments, extender pigments, plasticizers, desiccants, stabilizers, etc. are added to conventionally used ink binder resins such as urethane, acrylic, nitrocellulose, and rubber. It is a layer comprised by the ink which becomes. Characters, pictures, and the like are formed by this printing. As a forming method, for example, a known printing 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 can be used. The dry film thickness (solid content) of the printing layer may be, for example, 0.1 to 2.0 μm.

  In the transparent gas barrier film laminate having retort suitability according to claim 2 of the present invention shown in FIG. 2, the intermediate layer 6 made of stretched nylon film laminated and bonded via the polyester-based first adhesive layer 5 is a bag. A biaxially stretched nylon film is generally used from the viewpoint of mechanical strength and thermal stability. The thickness is determined according to the material and required quality, but is generally in the range of 10 to 30 μm.

  Further, on the intermediate layer 6 made of a stretched nylon film, a polyester-based two-component curable second adhesive layer 7 (or styrene maleic anhydride copolymer containing 10 to 1% by weight of a styrene maleic anhydride copolymer) is used. Heat-seal layer 8 (sealant layer) through a polyester-based two-component curable second adhesive layer 7) containing 10 to 1% by weight and having a glass transition point (Tg) of the polyester resin as the main component of 10 ° C. or less Are laminated. As a lamination method, it can laminate | stack by well-known methods, such as the dry lamination method bonded together using a two-component curing type polyester-type adhesive agent. In addition, although the thickness of the heat seal layer 8 is decided according to the objective, generally it is the range of 15-200 micrometers. As a laminating method, it is common to use a dry laminating method or the like in which the above two-component curable adhesive of polyester is used for lamination, but it is also possible to laminate by other known methods.

The polyester-based two-component curable second adhesive layer 7 contains at least 10 to 1% by weight of a styrene / maleic anhydride copolymer in the same manner as the polyester-based first adhesive layer 5 described above. The second adhesive layer 7 absorbs and relaxes stress from the intermediate layer 6 and the sealant layer 8 that are generated during various sterilization treatments such as boil sterilization and retort sterilization, which are considered to be a cause of barrier lowering, The 4th which protects the inorganic compound vapor deposition thin film layer 3 which is a 1st layer which forms a gas barrier layer, the gas barrier film layer 4 which is a 2nd layer, and the 1st adhesive bond layer 5 which is a 3rd layer. The layer has the purpose and function as a gas barrier protective layer.

  The polyester-based two-component curable second adhesive layer 7 containing a styrene maleic anhydride copolymer as a fourth layer for protecting the gas barrier layer will be described in more detail. Is a copolymer obtained by copolymerizing styrene and maleic anhydride and purified by a known technique, and the copolymerization ratio and the like are not particularly limited as long as the above object can be achieved. By including the copolymer, the adhesion between the stretched nylon film and the intermediate layer 6 and the heat seal layer 8 (sealant layer) is improved, and furthermore, the dimensional stability during high temperature sterilization is excellent. It becomes possible to absorb and relieve the stress applied to the intermediate layer 6 and the heat seal layer 8.

  As a coating method of the two-component curable second adhesive layer 7, it can be formed by a known coating method. For example, it is formed by a separate machine on one side of a laminated (laminated) intermediate layer of the stretched nylon or one side of a polyolefin (polyethylene, polypropylene, etc.) film that is laminated on the surface of the intermediate layer and becomes a heat seal layer 8. Alternatively, the coating method may be a known method such as a gravure printing method.

  The thickness of the polyester-based two-component curable second adhesive layer 7 varies depending on the type, function, and application used, but is not particularly limited as long as the influence of stress or the like can be absorbed / relieved. However, if the thickness is less than 0.1 μm, it is difficult to obtain a uniform coating film, and the relaxation effect may be lowered, which is not preferable. If it is thick, the relaxation effect is sufficient, but there is a problem of cost. In general, the dry thickness is preferably in the range of 0.1 to 10 mm, and more preferably in the range of 0.3 to 5 mm.

  The transparent gas barrier film laminate having retort suitability according to the present invention will be further described with reference to specific examples.

<Preparation of primer solution>
In a diluting solvent (ethyl acetate), 10 parts by weight of acrylic polyol was mixed with 1 part by weight of γ-isocyanatopropyltrimethylsilane and stirred. Next, a 7 to 3 mixture of DI and IPDI was added as an isocyanate compound so that the isocyanate groups of this isocyanate compound were equivalent to the hydroxyl groups of the acrylic polyol. A solution obtained by diluting this mixed solution to 2% by weight as the total concentration of the added compound was used as a primer solution.

<Preparation of gas barrier coating solution>
The following [I] liquid and [II] liquid mixed at 6/4 in a blending ratio (wt%) were used as a gas barrier coating solution.

[I] Liquid: 89.6 g of hydrochloric acid (0.1N) added to 10.4 g of tetraethoxysilane, stirred for 30 minutes, and hydrolyzed to a hydrolyzed solution having a solid content of 3 wt% (in terms of SiO ₂ ) [II] Liquid: Polyvinyl alcohol 3 wt% water / isopropyl alcohol solution (water: isopropyl alcohol weight ratio 90:10)
<Preparation of Styrene / Maleic Anhydride-Containing Polyester Two-Component Curing Adhesive>
In a polyester-based two-part curable adhesive, a styrene / maleic anhydride copolymer was added to a urethane resin as a main component so that the amount of styrene / maleic anhydride copolymer was 3% by weight. Used as a coalescence-containing adhesive.

<Example 1>
As the plastic substrate 1, the primer solution described above was applied and dried on one side of a 12 μm thick biaxially stretched polyethylene terephthalate (PET) film by gravure coating to form a primer layer 2 having a thickness of 0.1 μm. Next, metallic aluminum was evaporated by a vacuum vapor deposition apparatus using an electron beam heating method, oxygen gas was introduced therein, and aluminum oxide having a thickness of 15 nm was vapor-deposited to form a vapor-deposited thin film layer 3 made of an inorganic oxide. Subsequently, the gas barrier coating solution described above was applied and dried by a gravure coating method to form a gas barrier coating layer 4 having a thickness of 0.4 μm. Further, the above-mentioned polyester-based two-component curable adhesive containing a styrene / maleic anhydride copolymer is applied and dried by a gravure coating method to obtain a polyester-based two-component containing a styrene / maleic anhydride copolymer having a thickness of 1 μm. A liquid curable first adhesive layer 5 was formed.

  Next, an intermediate layer 6 was formed by laminating a stretched nylon film by a dry laminating method through the polyester two-component curable first adhesive layer 5.

  Next, an unstretched polypropylene film having a thickness of 70 μm is used as the heat-sealable (heat-sealable) polyolefin resin on the intermediate layer 6 made of the stretched nylon film, and the above-mentioned polyester system containing styrene / maleic anhydride. A two-part curable adhesive (polyethylene terephthalate resin glass transition point: 10 ° C. or less), which is formed by applying and drying by gravure coating, is a 1 μm-thick styrene / maleic anhydride-containing polyester-based two-part curable type A heat seal layer 8 was laminated by laminating by a dry laminating method through two adhesive layers 7, and a transparent gas barrier film laminate (packaging material) having retort suitability of the present invention was obtained (see FIG. 2).

<Comparative Example 1>
The same as in Example 1 except that the styrene / maleic anhydride copolymer is not contained in the polyester two-component curable adhesive of the first adhesive layer 5 and the second adhesive layer 7 in Example 1 above. Thus, a film laminate (packaging material) having the same laminate structure as in FIG. 2 was obtained.

<Test>
The packaging material obtained in Example 1 and the packaging material obtained in Comparative Example 1 are cut into a rectangular shape, and each of the packaging materials is overlapped and produced by heat-sealing a pouch having four sides as a seal portion. Then, 150 g of water was filled as the contents. Thereafter, retort sterilization was performed at 121 ° C. for 30 minutes.

<Evaluation results>
As an evaluation, oxygen permeability before and after retort (unit: cm ³ / m ² / day, measurement conditions: 30 ° C., 70% RH) was evaluated, and the results are shown in Table 1 below.

[Table 1]
Sample oxygen permeability (cm ³ / m ² / day · atm)
Before retort sterilization After retort sterilization Composite evaluation Example 1 0.5 0.6 ○
Comparative Example 1 0.5 2.7 ×
The pouch using the packaging material of Comparative Example 1 is a condition that is used as the packaging material described above, transparency that allows the contents to be directly seen through, gas that affects the contents, and the like. The pouch using the packaging material of Example 1 was found to satisfy all of these conditions, although it does not satisfy all of the advanced gas barrier properties comparable to the metal foil to be blocked and various sterilization resistances.

The sectional side view explaining an example of the transparent gas barrier film laminated body which has the retort aptitude of this invention. Side sectional drawing explaining the other example of the transparent gas barrier film laminated body which has the retort aptitude of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Plastic base material 2 ... Primer layer 3 ... Vapor deposition thin film layer 4 which consists of inorganic oxides ... Gas barrier coating layer 5 ... First adhesive layer 6 containing styrene / maleic anhydride ... Intermediate layer 7 made of stretched nylon film ... Styrene / Maleic anhydride-containing second adhesive layer 8 ... heat seal layer (sealant layer)

Claims (11)

  On at least one surface of a transparent plastic film substrate made of a polyester-based resin, a primer layer made of a composite of an acrylic polyol, an isocyanate compound and a silane coupling agent, a vapor-deposited thin film layer made of an inorganic oxide, and a water-soluble polymer A gas barrier coating layer formed by applying an aqueous solution or water / alcohol mixed solution containing one or more metal alkoxides or a hydrolyzate thereof and drying by heating, and a polyester-based two-component curing type containing a styrene-maleic anhydride copolymer A transparent gas barrier film laminate having retort suitability, wherein an adhesive layer and a heat seal layer made of a polyolefin resin are sequentially laminated in this order.   On at least one surface of a transparent plastic film substrate made of a polyester-based resin, a primer layer made of a composite of an acrylic polyol, an isocyanate compound and a silane coupling agent, a vapor-deposited thin film layer made of an inorganic oxide, and a water-soluble polymer A gas barrier coating layer formed by applying an aqueous solution or water / alcohol mixed solution containing one or more metal alkoxides or a hydrolyzate thereof and drying by heating, and a polyester-based two-component curing type containing a styrene-maleic anhydride copolymer A first adhesive layer, an intermediate layer made of a stretched nylon film, a polyester-based two-component curable second adhesive layer containing a styrene-maleic anhydride copolymer, and a heat seal layer made of a polyolefin-based resin, Transparent gas barrier having retort suitability characterized by being sequentially laminated Irumu laminate.   The transparent gas barrier film laminate having retort suitability according to claim 1, wherein the polyester-based two-component curable adhesive layer contains a styrene maleic anhydride copolymer in a proportion of 10 to 1% by weight.   2. The transparent gas barrier film laminate having retort suitability according to claim 1, wherein a glass transition point (Tg) of a polyester resin as a main component in the polyester two-component curable adhesive layer is 10 ° C. or less.   At least the first adhesive layer, or the first adhesive layer and the second adhesive layer are polyester-based two-component curable adhesives, and the styrene maleic anhydride copolymer is 10 to 1% by weight. The transparent gas barrier film laminate having retort suitability according to claim 2, characterized by comprising   The retort according to claim 2, wherein a glass transition point (Tg) of a polyester resin as a main component in at least the first adhesive layer or the first adhesive layer and the second adhesive layer is 10 ° C or lower. A transparent gas barrier film laminate having suitability.   The transparent gas barrier having retort suitability according to any one of claims 1 to 6, wherein the silane coupling agent has an organic functional group that reacts with at least one of a hydroxyl group of an acrylic polyol or an isocyanate group of an isocyanate compound. Film laminate.   8. The transparent gas barrier film laminate having retort suitability according to claim 7, wherein the organic functional group contained in the silane coupling agent is an isocyanate group, an epoxy group, or an amino group.   The transparent gas barrier film laminate having retort suitability according to any one of claims 1 to 8, wherein the inorganic oxide is aluminum oxide, silicon oxide, or a mixture thereof.   The transparent gas barrier film laminate having retort suitability according to any one of claims 1 to 9, wherein the metal alkoxide is tetraethoxysilane, triisopropoxyaluminum, or a mixture thereof.   The transparent gas barrier film laminate having retort suitability according to any one of claims 1 to 10, wherein the water-soluble polymer is polyvinyl alcohol.

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