TW202019687A - Laminated film - Google Patents

Abstract

To provide a laminated film suitable for packaging such as retort food that can reduce the amount of packaging material, having excellent resistance to bag breakage, and can keep standing when used as a standing pouch. A laminated film comprising at least a base material layer and a sealant layer, wherein (a) the base material layer is a biaxially stretched polyester film having a thickness of 9 μm to 25 μm, containing 70% by mass or more of polybutylene terephthalate, (b) the piercing strength of the laminated film is 9.0N or more, and (c) the loop stiffness value X (mN / 25 mm) of the laminated film is 80 or more, and (e) the total thickness is 59 to 160 μm.

Description

Laminated film

The invention relates to a laminated film used in the packaging field of food, medicine, industrial products and the like. More specifically, it relates to a laminated film, which is composed of a laminated film formed of an inorganic thin film layer or a metal foil on a base layer and a sealant layer, and uses polybutylene terephthalate (hereinafter abbreviated as In the case where the laminated film of one layer of PBT film instead of the polyester film and the nylon film is used as the base material layer, it is also excellent in puncture resistance or bag-breaking resistance, and has excellent self-standing properties as a stand-up bag.

Previously, in order to prevent the deterioration of contents such as food, packaging materials in which various plastic films, paper, metal foil, and other substrates were laminated were developed. In general, a heat seal layer is provided on the innermost layer of these packaging materials, and these are superimposed and sealed, thereby making bags into various forms. Then, the contents are filled from the opening, heat-sealed and hermetically sealed, thereby completing the final form of the packaged product. Especially in food applications, retort pouches are widely known as packaging forms that can be stored for a long period of time, and have been practically applied in all fields. Furthermore, in recent years, in the sterilization bags described above, self-supporting bags have been used for the purpose of reducing packaging materials that become waste after use. The self-supporting bags can be displayed directly in the storefront without being placed in an outer box. The sterilization bag itself has a self-supporting structure.

On the other hand, the basic properties required for the packaging material for cooking include safety, odorless and odorless, hot water resistance, light-shielding property, fragrance retention, discoloration resistance, various gas barrier properties, pressure resistance, impact, puncture, etc. The strength, bending resistance, and airtightness are designed according to the conditions of the heat treatment, the type of content, and the amount of content, etc., to design the optimal laminate structure. For example, in order to impart hot water resistance, toughness (independence), gloss or printability, and fragrance retention, a biaxially stretched polyethylene terephthalate film (hereinafter abbreviated as OPEN) is selected to impart impact resistance or needle resistance Porosity and puncture resistance, selected biaxially stretched nylon film (hereinafter referred to as ONy), in order to block light, oxygen, water vapor, selected aluminum foil or aluminum vapor-deposited film or gas barrier coating layer, in order to give heat sealability, selected The unstretched polypropylene film (hereinafter abbreviated as CPP), polyethylene film, etc., are laminated by dry lamination or the like to obtain packaging materials for cooking.

The lamination structure of the packaging material for cooking includes, for example, lamination from the outside of OPET//ONy//CPP, OPET//AL//CPP, OPET//ONy//AL//CPP, OPET//AL// Configurations such as ONy//CPP are representative configurations (refer to Patent Document 1, Patent Document 2, Patent Document 3, and Patent Document 4). As the substrate layer of the packaging material for cooking, OPEN or ONy is generally used. Although OPET has the advantages of high hot water resistance, on the other hand, it has the weakness of low impact strength, puncture strength, and low resistance to pinholes. On the other hand, although ONy has high impact strength or puncture strength, since the film itself is hygroscopic, there is a disadvantage that if it comes into contact with hot water, the strength will be reduced due to hydrolysis. From the above point of view, especially in the case of severe cooking conditions above 130°C or where high compressive strength and impact resistance are required, in order to complement the shortcomings of the two substrates, OPEN and ONy are used as the basis Wood layer.

However, since the two base materials are used together, there is a problem in terms of impact on resource saving or environmental load. In addition, as the number of lamination steps increases, there is room for improvement in workability. Therefore, in recent years, an attempt has been made to replace the above-mentioned OPEN and ONy buildup with one layer of film. For example, Patent Literature 6 and Patent Literature 7 disclose biaxially stretched films including PBT. According to the above technique, it is excellent in impact resistance or puncture resistance, and can also withstand severe heat treatment such as cooking treatment, so there is a possibility that one layer of film may be used instead of OPEN and ONy. However, when the film formed by laminating the base material layer and the sealant is processed into a packaging bag such as a stand-up pouch, the toughness of the laminated film is insufficient, so there is a problem that the stand-alone pouch has insufficient self-sustainability. . [Prior Technical Literature] [Patent Literature]

Patent Document 1: Japanese Patent Publication No. 63-31961. Patent Document 2: Japanese Patent Laid-Open No. 5-38779. Patent Document 3: Japanese Patent Laid-Open No. 2002-326306. Patent Document 4: Japanese Patent Laid-Open No. 2005-178311. Patent Document 5: Japanese Patent Laid-Open No. 2017-094746. Patent Literature 6: WO2014/077197.

[Problems to be solved by the invention]

The present invention has been completed on the background of the aforementioned problems of the prior art. That is, an object of the present invention is to provide a laminated film that can reduce the amount of packaging materials and is excellent in bag-break resistance, and can also ensure sufficient self-standing property when used as a stand-up bag, and is suitable for packaging for cooking foods and the like. [Means to solve the problem]

The inventors of the present invention have found that the rigidity of a laminated film formed by laminating a film base layer composed of polybutylene terephthalate (PBT) as a main component and a sealant layer is within a specific range, even The base material layer is one layer, which is also excellent in hot water resistance and impact resistance, and can ensure self-reliance when processed into a stand-up pouch.

That is, the present invention is composed of the following structure. (1) A laminated film consisting of at least a base material layer and a sealant layer with a total thickness of 59 μm to 160 μm, characterized in that: (a) The base material layer contains 70 mass% of polybutylene terephthalate % Or more of a biaxially stretched polyester film with a thickness of 9 μm to 25 μm; (b) the puncture strength of the laminate film is 9.0 N or more; (c) the ring stiffness value X (mN/25 mm) of the laminate film is 80 or more. (2) The laminated film according to (1), wherein the base material layer has an inorganic thin film layer on at least one side. (3) The laminated film according to (2), wherein the inorganic thin film layer is a layer composed of oxides of silicon oxide and/or aluminum oxide. (4) The laminated film according to (2) or (3), characterized in that it has an adhesive layer between the base material layer and the inorganic thin film layer. (5) The laminated film according to any one of (2) to (4), characterized in that it has a protective layer on the inorganic thin film layer. (6) A packaging bag composed of the laminated film as described in any one of (1) to (5) above. (7) The packaging bag as described in (6) above, characterized in that it is used as a stand-up bag. (8) The packaging bag according to (7), characterized in that when the value of the ring stiffness of the laminated film is X, the content Y (g) of the self-supporting bag satisfies the following formula (1). 1.8X≦Y≦3.8X Formula (1) (9) The packaging bag according to any one of (6) to (8), characterized in that it is used for cooking. (10) The packaging bag according to any one of (6) to (8), characterized in that it is used for heating in a microwave oven. [Effect of invention]

According to the present invention, it is possible to provide a laminated film and a packaging bag. The laminated film can reduce the amount of packaging materials and is excellent in bag-breaking resistance. It can also ensure sufficient self-reliance when used as a stand-up bag, and is suitable for liquid packaging for cooking food and the like .

Hereinafter, the present invention will be described in detail. [Base layer film] As the base material layer used in the present invention, a film containing PBT as a main component is used. The content rate of PBT in the base material layer is preferably 60% by mass or more, and more preferably 70% by mass or more. If it is less than 60% by mass, the impact strength or pinhole resistance will decrease, and the film properties will be insufficient. In the PBT used as the main component of the substrate layer, as the dicarboxylic acid component, terephthalic acid is preferably 90 mol% or more, more preferably 95 mol% or more, and further preferably 98 mol% or more , The best is 100 mol%. As the diol component, 1,4-butanediol is preferably 90 mol% or more, more preferably 95 mol% or more, and still more preferably 97 mol% or more, and most preferably does not include polymerization by 1 Components other than the by-products formed by the ether bond of 4-butanediol.

The base material layer used in the present invention may contain a polyester resin other than PBT for the purpose of adjusting the film-forming property during stretching or the mechanical properties of the obtained film. Examples of polyester resins other than PBT include polyethylene terephthalate (hereinafter abbreviated as PET), polyethylene naphthalate, polybutylene naphthalate, and polytrimethylene terephthalate. , And the copolymer is selected from the group consisting of isophthalic acid, phthalic acid, naphthalene dicarboxylic acid, biphenyl dicarboxylic acid, cyclohexane dicarboxylic acid, adipic acid, azelaic acid and sebacic acid PBT resins made from at least one dicarboxylic acid, copolymerized with ethylene glycol, 1,3-propanediol, 1,2-propanediol, neopentyl glycol, 1,5-pentanediol, 1,6 -PBT composed of at least one diol component in the group consisting of hexanediol, diethylene glycol, cyclohexanediol, polyethylene glycol, polytetramethylene glycol, and polycarbonate diol Resin.

The upper limit of the addition amount of the polyester resin other than PBT is 40% by mass or less, preferably 30% by mass or less. If the addition amount of the polyester resin other than PBT exceeds 40% by mass, the mechanical properties of PBT may be impaired, impact strength, pinhole resistance, or bag-break resistance may be insufficient, and the transparency Or the gas barrier is reduced.

The lower limit of the intrinsic viscosity of the PBT resin used in the present invention is preferably 0.9 dl/g, more preferably 0.95 dl/g, and still more preferably 1.0 dl/g. When the inherent viscosity of the raw material PBT resin is less than 0.9dl/g, the inherent viscosity of the film obtained by film formation may decrease, and the puncture strength, impact strength, pinhole resistance, or bag resistance may decrease. . The upper limit of the inherent viscosity of the PBT resin is preferably 1.3 dl/g. If the upper limit is exceeded, the stress during stretching may become too high, and the film formability may deteriorate. When PBT with a high inherent viscosity is used, the melt viscosity of the resin becomes high. Therefore, the extrusion temperature must be set to a high temperature. However, if the PBT resin is extruded at a higher temperature, decomposition products may easily occur.

The aforementioned PBT resin may optionally contain previously known additives such as slip agents, stabilizers, colorants, antistatic agents, ultraviolet absorbers, and the like.

As the type of the aforementioned slip agent, in addition to inorganic slip agents such as silica, calcium carbonate, alumina, etc., organic slip agents are preferred, and silicon dioxide and calcium carbonate are more preferred. Among them, the haze is reduced In this respect, silicon dioxide is particularly preferred. These slip agents can show transparency and slippage.

The lower limit of the concentration of the aforementioned slip agent is preferably 100 ppm, more preferably 500 ppm, and still more preferably 800 ppm. If the above lower limit is not reached, the sliding property of the base material layer film may decrease. The upper limit of the concentration of the slip agent is preferably 20,000 ppm, more preferably 10,000 ppm, and still more preferably 1,800 ppm. If the upper limit is exceeded, the transparency may decrease.

The base layer film in the present invention is preferably a resin having the same composition throughout the entire area of the film. The lower limit of the thickness of the base layer film in the present invention is preferably 3 μm, more preferably 5 μm, and still more preferably 8 μm. If it is 3 μm or more, the strength as a base layer film becomes sufficient. The upper limit of the thickness of the base layer film is preferably 100 μm, more preferably 75 μm, and still more preferably 50 μm. If it is 100 μm or less, the target processing of the present invention becomes easier.

Next, the method of manufacturing the base layer film used in the present invention will be specifically described. It is not limited to these. [Step of forming unstretched sheet in the production of base layer film] First, the film raw material is vacuum dried or hot air dried. Then, the measured raw materials are mixed and supplied to the extruder, heated and melted, and melt-cast into a sheet shape. Furthermore, using an electrostatic application method, the molten resin sheet was closely adhered to a cooling roll (casting roll) to be cooled and solidified to obtain an unstretched sheet. The so-called electrostatic application method refers to a method in which a molten resin sheet is brought into contact with the vicinity of the rotating metal roller, and a voltage is applied to an electrode provided in the vicinity of the surface of the resin sheet opposite to the surface in contact with the rotating metal roller, thereby The resin sheet is charged so that the resin sheet is in close contact with the rotating cooling roller.

The lower limit of the heating melting temperature of the resin is preferably 200°C, more preferably 250°C, and still more preferably 260°C. If the lower limit is not reached, the ejection may become unstable. The upper limit of the resin melting temperature is preferably 280°C, and more preferably 270°C. If the upper limit is exceeded, the resin decomposes and the film becomes brittle.

When the molten polyester resin is extruded and cast on a cooling roll, it is preferable to reduce the difference in crystallinity in the width direction of the unstretched sheet. As a specific method for reducing this difference, when the melted polyester resin is extruded and cast, the melted raw resin is layered and cast, and the temperature of the cooling roll is set to a low temperature.

The method of multi-layering the melted raw material resin is not particularly limited, but in terms of simplicity of the equipment or maintainability, a static mixer and/or a multi-layer feed block are preferred. When the molten raw material resin is multi-layered, the number of layers is preferably 60 or more. More preferably, it is 500. If the number of stacked layers is too small, the distance between the layer interfaces becomes long and the crystal size becomes too large, the difference in crystallinity in the width direction or the crystallinity near both ends of the sheet increases, and the film formation becomes unstable. The upper limit of the number of stacked layers is not particularly limited, but is preferably 100,000, more preferably 10,000, and still more preferably 7,000. Even if the number of theoretical layers is extremely large, the layering effect may be saturated.

In the case of multi-layering with a static mixer, the number of theoretical layers can be adjusted by selecting the number of components of the static mixer. Static mixers are generally known as static mixers (pipeline mixers) without a driving part, and the fluid entering the mixer is sequentially mixed and mixed by components. However, if a high-viscosity fluid is passed through a static mixer, the high-viscosity fluid will be divided and layered to form a layered fluid. Each time it passes through one of the components of the static mixer, the high-viscosity fluid is divided into two layers, which are then merged and stacked. Therefore, if a high-viscosity fluid is passed through a static mixer with the number of elements n, a layered fluid with a theoretical layering number N = (2 to the power of n) is formed.

The upper limit of the temperature of the cooling roll when the melted polyester resin is extruded and cast on the cooling roll is preferably 40°C. If the upper limit is exceeded, the crystallinity may become too high and stretching may become difficult. The upper limit of the temperature of the cooling roller is preferably 25°C. In addition, when the temperature of the cooling roll is within the above range, in order to prevent condensation, it is preferable to reduce the humidity of the environment near the cooling roll in advance. The temperature difference in the width direction of the surface of the cooling roller is preferably small. The lower limit of the temperature of the cooling roller is preferably -10°C. If the above lower limit is not reached, the effect of suppressing crystallization may be saturated. The thickness of the unstretched sheet is preferably in the range of 15 μm to 2500 μm.

[Vertical Stretching Step and Horizontal Stretching Step in the Production of Base Layer Film] Next, the extension method will be described. The stretching method can be synchronous biaxial stretching or gradual biaxial stretching, but in order to improve the puncture strength, it is necessary to increase the surface alignment in advance, and in terms of fast film production speed and high productivity, the best stepwise biaxial stretching The shaft extends.

The lower limit of the extension temperature in the longitudinal extension direction is preferably 55°C, and more preferably 60°C. If it is 55° C. or higher, it is not likely to cause fracture. In addition, since the longitudinal alignment of the film is not too strong, the shrinkage stress during the heat fixation process can be suppressed, and a film with less molecular alignment strain in the width direction can be obtained. The upper limit of the extension temperature in the longitudinal extension direction is preferably 100°C, more preferably 95°C. If the temperature is 100° C. or lower, the orientation of the film is not too weak, so the mechanical properties of the film do not decrease.

The lower limit of the stretching magnification in the longitudinal stretching direction is preferably 2.8 times, and particularly preferably 3.0 times. If it is 2.8 times or more, the surface alignment becomes larger, the puncture strength of the film is improved, and the thickness accuracy of the film is improved. The upper limit of the stretching magnification in the longitudinal stretching direction is preferably 4.3 times, more preferably 4.0 times, and particularly preferably 3.8 times. If it is 4.3 times or less, the lateral alignment of the film is not too strong, the shrinkage stress during the heat fixing process is not too large, and the strain of the molecular alignment in the lateral direction of the film becomes small, and as a result, the straight-line tearing property in the longitudinal direction is improved. In addition, the improvement effect of uneven mechanical strength or thickness is saturated within this range.

The lower limit of the elongation temperature in the transverse elongation direction is preferably 60°C. If it is 60°C or higher, it may not be easily broken. The upper limit of the stretching temperature in the transverse stretching direction is preferably 100°C. If it is 100°C or less, the degree of alignment in the transverse direction becomes large, so the mechanical properties are improved.

The lower limit of the stretching magnification in the lateral stretching direction is preferably 3.5 times, more preferably 3.6 times, and particularly preferably 3.7 times. If it is 3.5 times or more, the alignment in the lateral direction will not become too weak, and the mechanical properties or thickness unevenness will be improved. The upper limit of the stretching magnification in the lateral stretching direction is preferably 5 times, more preferably 4.5 times, and particularly preferably 4.0 times. If it is 5.0 times or less, the improvement effect of uneven mechanical strength or thickness becomes maximum (saturated) within this range.

[Heat fixing step in the production of base layer film] The lower limit of the heat fixing temperature in the heat fixing step is preferably 195°C, and more preferably 200°C. If it is 195° C. or higher, the thermal contraction rate of the film is reduced, and even after cooking treatment, the inorganic thin film layer is less likely to be damaged, so the gas barrier property is improved. The upper limit of the heat-fixing temperature is preferably 220°C. If it is 220°C or less, the base material film layer will not melt and become brittle.

[The heat relaxation step in the production of the base material layer film] After the heat fixing step, heat relaxation treatment is performed for the purpose of improving heat dimensional stability and the like. The lower limit of the temperature in the heat relaxation step is preferably 180°C, and more preferably 200°C. If the temperature is 180° C. or higher, the thermal contraction rate of the film is reduced, and even after the cooking treatment, the inorganic thin film layer is less likely to be damaged, so the gas barrier property is improved. The upper limit of the temperature in the heat relaxation step is preferably 220°C. If it is 220°C or less, the base material film layer does not melt and becomes brittle. The lower limit of the relaxation rate in the heat relaxation step is preferably 0.5%. If it is 0.5% or more, it may not be easily broken during heat fixing. The upper limit of the relaxation rate is preferably 10%. If it is 10% or less, the shrinkage in the longitudinal direction during heat fixation becomes small, and as a result, the molecular alignment strain at the film end becomes small, and the straight-line tearability is improved. In addition, the film is less susceptible to strain or the like, and uneven thickness is less likely to occur.

[Cooling step in production of base layer film] In the cooling step after the relaxation in the heat relaxation step, it is preferable to set the surface temperature of the end portion of the polyester film to 80° C. or lower. If the temperature of the film end portion after passing through the cooling step exceeds 80°C, the end portion will be stretched due to the tension applied when winding the film, and as a result, the thermal shrinkage in the longitudinal direction of the end portion becomes high, so the width of the reel The thermal shrinkage rate distribution in the direction becomes uneven. When this roll is heated and transported and subjected to vapor deposition processing, etc., there are stripe-like wrinkles, and the physical properties of the gas barrier film finally obtained become uneven in the width direction .

In the aforementioned cooling step, as a method of setting the surface temperature of the film end portion to 80° C. or less, in addition to adjusting the temperature or air volume in the cooling step, a shielding plate may be provided at the center side in the width direction of the cooling area to change the end portion A method of selective cooling, or a method of locally blowing cold air to the end of the film.

The lower limit of the degree of alignment (ΔNx) in the MD (Machine Direction; longitudinal direction) of the base layer film in the present invention is preferably 0.04, more preferably 0.045, and even more preferably 0.05. If the lower limit is not reached, the alignment is weak, and therefore sufficient impact strength as a base layer film cannot be obtained, and the resistance to breakage is reduced. In addition, when an inorganic thin film layer and a protective layer are provided on the base material layer film to form a laminated film, the tensile force and temperature applied during the formation of the protective film are easily extended, and the inorganic thin film layer is broken, so the gas barrier property is reduced Situation.

The upper limit of the MD direction alignment (ΔNx) of the base layer film in the present invention is preferably 0.09, more preferably 0.085, and still more preferably 0.08. Within the above range, the mechanical properties and straight-line tearability of the base layer film are better. In addition, the degree of alignment (ΔNx) in the MD direction is to measure the refractive index Nx in the MD direction, the refractive index Ny in the TD (Transverse Direction; transverse direction) direction, and the refractive index Nz in the thickness direction using an Abbe refractometer, and use ΔNx=Nx-( Ny + Nz)/2 formula.

The upper limit of the haze per unit thickness of the base layer film in the present invention is preferably 0.66%/μm, more preferably 0.60%/μm, and still more preferably 0.53%/μm. When printing is performed on a base film of 0.66%/μm or less, the quality of printed characters or images is improved.

In addition, the base layer film in the present invention may be subjected to corona discharge treatment, glow discharge treatment, flame treatment, surface roughening treatment as long as the object of the present invention is not impaired, and also known anchor coating may be performed Processing, printing, decoration, etc.

[Easy adhesion layer and its forming method] An easy adhesion layer may be provided on the base material layer film used in the laminated film of the present invention. In particular, in the case where the base film is formed with an inorganic thin film layer, in order to ensure gas barrier properties or lamination strength after retorting, it is preferable to provide an easy adhesion layer between the base film and the inorganic thin film layer. Examples of the easy-adhesion layer provided on the base layer film include urethane-based, polyester-based, acrylic-based, titanium-based, isocyanate-based, imide-based, and polybutadiene-based resins. A layer formed by adding hardeners such as epoxy, isocyanate, and melamine. Examples of the solvent include aromatic solvents such as benzene and toluene; alcohol solvents such as methanol and ethanol; ketone solvents such as acetone and methyl ethyl ketone; ester solvents such as ethyl acetate and butyl acetate; ethyl Polyol derivatives such as glycol monomethyl ether, etc. The resin composition used in these adhesive layers preferably contains a silane coupling agent having at least one organic functional group. Examples of the organic functional group include alkoxy groups, amine groups, epoxy groups, and isocyanate groups. By adding the aforementioned silane coupling agent, the lamination strength after cooking treatment is further improved.

Among the resin compositions used in the aforementioned easy-adhesion layer, it is preferable to use a mixture of a resin containing an oxazoline group, an acrylic resin and a urethane resin. The oxazoline group has a high affinity with the inorganic thin film. In addition, it can react with the oxygen-deficient portion of the inorganic oxide generated during the formation of the inorganic thin film layer or the metal hydroxide, showing strong adhesion to the inorganic thin film layer. In addition, the unreacted oxazoline group present in the easy-adhesion layer can react with the carboxylic acid terminal generated by the hydrolysis of the base layer film and the easy-adhesion layer to form a crosslink.

As a method of forming the aforementioned easy-adhesion layer, for example, a conventionally known method such as a coating method can be used. Among the coating methods, a preferred method includes an offline coating method and an in-line coating method. For example, in the case of the in-line coating method performed in the step of manufacturing the substrate layer film, the conditions of drying or heat treatment during coating also depend on the coating thickness or the conditions of the device, but it is preferably immediately after coating It is preferable to set the temperature to about 50° C. to 250° C. in the preheating zone or the stretching zone of the stretching step to feed the stretching step to the right angle direction and to perform drying in the stretching step.

[Inorganic thin film layer and its forming method] A gas barrier layer may be provided on the base material layer of the laminated film of the present invention. The inorganic thin film layer and its forming method will be described. The inorganic thin film layer is a thin film composed of metal or inorganic oxide. The material forming the inorganic thin film layer is not particularly limited as long as it can be made into a thin film, and from the viewpoint of gas barrier properties, preferably silicon oxide (silicon oxide), aluminum oxide (aluminum oxide), silicon oxide, and oxide Inorganic oxides such as mixtures of aluminum. In particular, the compound oxide of silicon oxide and aluminum oxide is preferred in terms of both flexibility and compactness of the thin film layer. In this composite oxide, the mixing of silicon oxide and aluminum oxide is preferably within a range of 20% by mass to 70% by mass based on the mass ratio of metal. If the Al concentration is less than 20% by mass, the water vapor barrier property may become low. On the other hand, if it exceeds 70% by mass, the inorganic thin film layer tends to become hard, and the film may be damaged during secondary processing such as printing or lamination, and the gas barrier property may be reduced. In addition, silicon oxide here refers to various silicon oxides such as SiO or SiO ₂ or a mixture of these silicon oxides, and aluminum oxide refers to various aluminum oxides such as AlO or A1 ₂ O ₃ or these aluminum oxides mixture.

The film thickness of the inorganic thin film layer is usually 1 nm to 100 nm, preferably 5 nm to 50 nm. If the thickness of the inorganic thin film layer is less than 1 nm, it may not be easy to obtain satisfactory gas barrier properties. On the other hand, even if it exceeds 100 nm and is excessively thickened, the gas barrier properties corresponding to this thickness cannot be improved. The effect is unfavorable in terms of bending resistance or manufacturing cost.

The method for forming the inorganic thin film layer is not particularly limited, and for example, a physical vapor deposition method (PVD (Physical Vapor Deposition) method) such as vacuum evaporation method, sputtering method, ion plating method, or the like is suitably used, or A well-known vapor deposition method such as a chemical vapor deposition method (CVD (Chemical Vapor Deposition) method) may be used. In the following, a typical method of forming an inorganic thin film layer will be described using silicon oxide and aluminum oxide based films as examples. For example, when a vacuum evaporation method is used, a mixture of SiO ₂ and A1 ₂ O ₃ or a mixture of SiO ₂ and Al can be preferably used as a raw material for evaporation. As these vapor deposition raw materials, ordinary particles can be used. In this case, the size of each particle is preferably such that the pressure during vapor deposition does not change, and the preferred particle size is 1 mm to 5 mm. Heating can use resistance heating, high frequency induction heating, electron beam heating, laser heating and other methods. In addition, reactive vapor deposition in which oxygen, nitrogen, hydrogen, argon, carbon dioxide, water vapor, or the like is introduced as a reaction gas, or methods such as ozone addition and ion assist may be used. Furthermore, a bias can be applied to the vapor-deposited body (laminated film for vapor deposition), or the vapor-deposited body can be heated or cooled, etc., and the film-forming conditions can be arbitrarily changed. Such a vapor deposition material, reaction gas, bias voltage, heating, cooling, etc. of the vapor-deposited body can be similarly changed when the sputtering method or the CVD method is used.

[Protective layer and its forming method] When the gas barrier layer is provided on the base layer film of the laminated film of the present invention, a protective layer may be further provided on the gas barrier layer. Describe the protective layer and its formation method. In the case where the gas barrier layer is an inorganic thin film layer such as a metal oxide layer, the inorganic thin film is not a completely dense film, but has minute defective parts scattered. Applying a specific resin composition for a protective layer to be described later on the inorganic thin film layer to form a protective layer, whereby the resin in the resin composition for the protective layer penetrates into the defective portion of the inorganic thin film layer, as a result, the effect of stabilizing the gas barrier property can be obtained . In addition, by using a material with gas barrier properties for the protective layer itself, the gas barrier performance of the laminated film can be greatly improved.

Examples of the protective layer include resins such as urethane resins, polyester resins, acrylic resins, titanate resins, isocyanate resins, imine resins, and polybutadiene resins. A layer formed by adding hardeners such as epoxy-based hardener, isocyanate-based hardener, and melamine-based hardener. Examples of the solvent for the resin include aromatic solvents such as benzene and toluene, alcohol solvents such as methanol and ethanol, ketone solvents such as acetone and methyl ethyl ketone, and ester solvents such as ethyl acetate and butyl acetate. , Ethylene glycol monomethyl ether and other polyol derivative system solvents, etc. The urethane resin is preferred because the polar group of the urethane bond interacts with the inorganic thin film layer and has flexibility due to the presence of an amorphous portion, so even when a bending load is applied, It can also suppress damage to the inorganic thin film layer.

The acid value of the urethane resin is preferably in the range of 10 mgKOH/g to 60 mgKOH/g. It is more preferably in the range of 15 mgKOH/g to 55 mgKOH/g, and still more preferably in the range of 20 mgKOH/g to 50 mgKOH/g. If the acid value of the urethane resin is in the aforementioned range, the liquid stability is improved when it is made into an aqueous dispersion, and the protective layer can be uniformly deposited on the highly polar inorganic film, so the coating appearance becomes good . The glass transition temperature (Tg) of the urethane resin is preferably 80°C or higher, and more preferably 90°C or higher. By setting Tg to 80° C. or higher, the swelling of the protective layer caused by the movement of molecules in the process of wet heat treatment (heating to heat preservation to temperature reduction) can be reduced.

In terms of improving gas barrier properties, the urethane resin is more preferably an urethane resin containing aromatic diisocyanate or aromatic aliphatic diisocyanate as a main constituent. Among them, particularly preferred is a component containing m-xylylene diisocyanate. By using the above resin, the cohesive force of the urethane bond can be further improved by the stacking effect of aromatic rings, and as a result, good gas barrier properties can be obtained.

In the present invention, it is preferable to set the ratio of the aromatic diisocyanate or aromatic aliphatic diisocyanate in the urethane resin to the range of 50 mol% to 100 mol% out of 100 mol% of the polyisocyanate component . The total ratio of aromatic diisocyanate or aromatic aliphatic diisocyanate is preferably 60 mol% to 100 mol%, more preferably 70 mol% to 100 mol%, and further preferably 80 mol% to 100 mol%. As such a resin, the "Takelac (registered trademark) WPB" series commercially available from Mitsui Chemicals Co., Ltd. can be preferably used. If the total ratio of aromatic diisocyanate or aromatic aliphatic diisocyanate is less than 50 mol%, there is a possibility that good gas barrier properties cannot be obtained.

From the viewpoint of improving the affinity with the inorganic thin film layer, the urethane resin preferably has a carboxylic acid group (carboxyl group). In order to introduce a carboxylic acid (salt) group into the urethane resin, for example, a polyol compound having a carboxylic acid group such as dimethylolpropionic acid or dimethylolbutyric acid as a polyol component may be used as a copolymerization component Just import. In addition, as long as the carboxylic acid group-containing urethane resin is synthesized and then neutralized with a salt-forming agent, the urethane resin of the water dispersion can be obtained. Specific examples of the salt-forming agent include trialkylamines such as ammonia, trimethylamine, triethylamine, triisopropylamine, tri-n-propylamine, tri-n-butylamine, and N-methyl N-alkylmorpholines such as morpholine and N-ethylmorpholine, N-dialkylalkanolamines such as N-dimethylethanolamine and N-diethylethanolamine, and the like. These can be used alone or in combination of two or more.

The upper limit of the heat shrinkage rate in the MD direction (longitudinal extension direction) of the base material layer of the present invention after heating at 150°C for 15 minutes is preferably 4.0%, more preferably 3.0%, and still more preferably 2%. If the upper limit is exceeded, the inorganic thin film layer may be cracked due to the dimensional change of the substrate layer film generated in the protective film formation step or the high-temperature treatment such as retort sterilization, and the gas barrier property may be lowered. In some cases, due to dimensional changes during processing such as printing, pitch deviations, etc. may occur.

The lower limit of the heat shrinkage rate in the MD direction of the base material layer in the present invention after heating at 150°C for 15 minutes is preferably 1%. If the above lower limit is not reached, there is a possibility that the tension applied in the protective film forming step after the formation of the inorganic thin film layer is easily extended, and the gas barrier property may be lowered. In addition, there are cases where the mechanical properties become brittle.

The upper limit of the heat shrinkage rate of the base material layer in the TD direction (transverse extension direction) after heating at 150°C for 15 minutes is preferably 3.0%, more preferably 2.0%, and still more preferably 1%. If the upper limit is exceeded, the inorganic thin film layer may be cracked due to the dimensional change of the substrate layer film generated in the protective film formation step or the high-temperature treatment such as retort sterilization, and the gas barrier property may be lowered. In some cases, due to dimensional changes during processing such as printing, pitch deviations, etc. may occur.

The lower limit of the heat shrinkage rate of the base material layer in the TD direction of the invention after heating at 150°C for 15 minutes is preferably -1.0%. If the above lower limit is not reached, a higher improvement effect cannot be obtained. In addition, there are cases where the mechanical properties become brittle.

[Laminated film and its forming method] The laminated film of the present invention is a laminated film composed of at least a base material layer film and a sealant layer. That is, it is a film in which a heat-sealing resin called a sealant is laminated on the base material layer film. The heat-sealable resin layer is usually laminated on the base material layer film by an extrusion lamination method or a dry lamination method. The heat-sealable resin layer is usually provided on the upper side of the inorganic thin film layer, but may also be provided on the outer side of the base material layer film (the surface opposite to the inorganic thin film layer side). As the thermoplastic polymer forming the heat-sealable resin layer, as long as the heat-sealability can be sufficiently exhibited, high-density polyethylene (abbreviated as HDPE), low-density polyethylene (abbreviated as LDPE), linear low density can be used Polyethylene resins such as polyethylene (abbreviated as LLDPE), polypropylene resins, ethylene-vinyl acetate copolymers, ethylene-α-olefin random copolymers, ionic polymer resins, etc.

Furthermore, in the laminated film of the present invention, at least one or more printed layers, other plastic substrates, and/or paper substrates, and metal foils may be laminated on the outside and/or between the laminated films.

As the printing ink for forming the printing layer, water-based and solvent-based resin-containing printing inks can be preferably used. Here, examples of the resin used in the printing ink include acrylic resins, urethane resins, polyester resins, vinyl chloride resins, vinyl acetate copolymer resins, and mixtures of these. It can also contain antistatic agents, light blocking agents, ultraviolet absorbers, plasticizers, slip agents, fillers, colorants, stabilizers, lubricants, defoamers, cross-linking agents, anti-blocking agents , Antioxidants and other well-known additives. The printing method for providing the printing layer is not particularly limited, and a known printing method such as an offset printing method, a gravure printing method, and a screen printing method can be used. For drying the solvent after printing, a known drying method such as hot air drying, hot roll drying, infrared drying, or the like can be used.

The lower limit of the ring stiffness value X (mN/25mm) of the laminated film of the present invention is preferably 80, more preferably 90, and most preferably 100. Here, the loop stiffness refers to the formation of a ring using a short strip of film cut into a predetermined size, and the ring rebound measured in a state where the ring is flattened by a predetermined amount in the radial direction Force is an indicator of membrane rigidity. If the ring stiffness of the laminated film does not reach the above lower limit, even in a case where the content is small, the self-standing property of the self-standing bag cannot be ensured, and there is a problem such as collapse during display on the storefront. The greater the value of the ring stiffness, the higher the rigidity of the laminated film. The method of measuring the ring stiffness will be described later.

In addition, if the content X (g) of the stand-up pouch is set to the range of the following formula (1) with respect to the value X of the ring stiffness of the laminated film of the present invention, a packaging pouch with good self-sustainability can be produced. 1.8X≦Y≦3.8X Formula (1)

As described above, by using the laminated film of the present invention, even after the wet heat treatment is applied, the puncture strength is excellent, and it has bag-breaking resistance and bending resistance, and sufficient self-standing property can be ensured when used as a stand-up bag. Since the self-standing pouches and other packaging bags previously made with the laminated film of the base film formed by stacking OPET and ONy can be made by using a laminated film composed of one base film, it can be widely used Food packaging materials for cooking or microwave heating. [Example]

Next, the present invention will be described in more detail by examples, but the present invention is not limited to the following examples. In addition, the evaluation of the film was performed by the following measurement method.

[Thickness of base material layer film] According to JIS K7130-1999 Method A, it is measured using a dial gauge.

[Pin Hole Resistance of Laminated Film] The laminated film obtained later is cut to a size of 20.3 cm (8 inches) × 27.9 cm (11 inches), and the cut rectangular test film is at a temperature of 23° C. and a relative humidity of 50 Adjust for more than 24 hours under the condition of %. Then, the rectangular test film was rolled up to form a cylindrical shape having a length of 20.32 cm (8 inches). Then, one end of the cylindrical film was fixed to the outer periphery of a disc-shaped fixing head of a Gelbo Flex Tester (manufactured by Rigaku Corporation, type NO.901) (according to the standard of MIL-B-131C), The other end of the cylindrical film was fixed to the outer periphery of a disc-shaped movable head of a tester opposed to the fixed head by 17.8 cm (7 inches). Then, one cycle of the bending test is continuously repeated for 2000 cycles at a rate of 40 cycles per minute. The foregoing one cycle of bending test is to move the movable head toward the fixed head along the axis of the two opposite parallel heads close to 7.6cm ( After rotating 4406.4 cm (2.5 inches) during 3.5 inches), these actions are performed in reverse to return the movable head to its original position. The aforementioned test was carried out at 5°C. Then, the number of pinholes generated in the portion of the test film within 17.8 cm (7 inches) × 27.9 cm (11 inches) other than the portion fixed to the outer periphery of the fixed head and the movable head (ie, every 497 cm is measured ² (77 square inches) of pinholes).

[Puncture strength of laminated film] The obtained laminated film was sampled 5 cm square, and measured using a digital display dynamometer "ZTS-500N" manufactured by IMADA Co., Ltd., an electric measuring stand "MX2-500N", and a puncture jig "TKS-250N" according to JIS Z1707 The puncture strength of the membrane. The unit is represented by N.

[Ring stiffness of laminated film] As a sample for ring stiffness measurement, a short strip-shaped film having a width of 25.4 mm and 110 mm was cut from the laminated film prepared in Examples and Comparative Examples. At this time, the longitudinal direction of the short strip-shaped film is aligned with the direction of the measurement object. The cut short strip-shaped film was set in a ring stiffness tester manufactured by Toyo Seiki Co., Ltd., and the rebound force was measured. The measurement frequency is set to 50 Hz. The value of the rebound force (mN) obtained in the measurement is set as the ring stiffness.

[Independence of stand-up bag] (1) Making of stand-up bag Using the laminated films shown in Examples, Comparative Examples, and Reference Examples described later, stand-up pouches of the shapes shown in FIGS. 1 and 2 were produced. The external dimensions of the body part of the stand-up pouch correspond to the capacity of the filled water, and are set to the dimensions shown in Table 1, respectively. The bottom heat seal is the same as a conventional stand-up pouch. It has a curved part that warps downward at the top, and heat seals the lower side of the curved part. At the bottom of the curved part, it has a length of 5 mm up to the lower end of the bag. The pattern of the sealing portion is heat-sealed to form the bottom, and the main body portion is formed by heat-sealing the left and right sides of the bag with a heat-sealing width of 5 mm. In addition, the unsealed upper part is opened as an opening for filling the contents. Then, from each of the unsealed upper openings, after filling the volume of water shown in Table 1 as the contents, the openings were deaerated and sealed to seal the bags to prepare self-standing pouches for evaluation of self-sustainability. In addition, the temperature at the time of heat sealing at the time of making a stand-up pouch is 160° C.×1 second in the case of LLDPE, and 200° C.×1 second in the case of no stretched polypropylene film. (2) Evaluation of independence The evaluation of the independence is evaluated by ○, △, and X according to the following criteria. ・Independence ○: The bottom of the self-supporting bag is maintained in a self-supporting state without being bent. △: The bottom of the self-standing bag is slightly deformed, but the self-standing state is maintained. ×: The bottom of the self-standing bag is bent, and the self-standing state cannot be maintained.

[Table 1]

The details of the raw resins and coating liquids used in the examples and comparative examples are described below. 1) PBT resin: The PBT resin used in the production of the substrate layer film A1 to the substrate layer film A3 described later is 1100-211XG (manufactured by CHANG CHUN PLASTICS CO., LTD., inherent viscosity 1.28dl/g) . 2) PET resin: The PET resin used in the production of the substrate layer film A1 to the substrate layer film A3 described later is a PET resin with an inherent viscosity of 0.62 dl/g manufactured by Toyobo Co., Ltd.

3) Resin with oxazoline group for easy adhesion layer (A): As a resin with oxazoline group, a commercially available water-soluble oxazoline group-containing acrylate (manufactured by Japan Catalyst Co., Ltd.) is prepared "Epocros (registered trademark) WS-300"; solid content 10%). The amount of oxazoline group in this resin was 7.7 mmol/g.

4) Acrylic resin (B) for easy adhesion layer: As an acrylic resin, prepare a commercially available 25% by mass emulsion of acrylic copolymer ("Mowinyl (registered trademark) 7980" manufactured by Nichigo-Mowinyl Co., Ltd.). The acid value (theoretical value) of this acrylic resin (B) is 4 mgKOH/g.

5) Urethane resin (C) for easy adhesion layer: As a urethane resin, prepare a commercially available dispersion of polyester urethane resin ("Takelac" manufactured by Mitsui Chemicals Co., Ltd.) (Registered trademark) W605"; solid content 30%). The acid value of the urethane resin was 25 mgKOH/g, and the glass transition temperature (Tg) measured by DSC (Differential Scanning Calorimetry; differential scanning calorimeter) was 100°C. In addition, the ratio of the aromatic diisocyanate or aromatic aliphatic diisocyanate to the entire polyisocyanate component measured by 1H-NMR (Proton Nuclear Magnetic Resonance) was 55 mol%.

6) Urethane resin for protective layer (D): As a urethane resin, prepare a commercially available dispersion of metaxylylene-containing urethane resin (Mitsui Chemical Co., Ltd.) Manufactured "Takelac (registered trademark) WPB341"; solid content 30%). The acid value of this urethane resin was 25 mgKOH/g, and the glass transition temperature (Tg) measured by DSC was 130°C. In addition, the ^ratio of the aromatic diisocyanate or aromatic aliphatic diisocyanate to the entire polyisocyanate component measured by ¹ H-NMR was 85 mol%.

7) Coating liquid 1 (coating 1) used in the easy adhesion layer Each material was mixed according to the following mixing ratio to prepare a coating liquid (resin composition for easy adhesion layer). Water 54.40 mass% Isopropyl alcohol 25.00% by mass Resin containing oxazoline group (A) 15.00% by mass Acrylic resin (B) 3.60% by mass Urethane resin (C) 2.00% by mass

8) Coating liquid 2 (coating 2) used in the protective layer The following coating agents were mixed to prepare a coating liquid 2. Here, the mass converted from the solid content of the urethane resin (E) is shown below. Water 60.00 mass% Isopropyl alcohol 30.00% by mass Urethane resin (D) 10.00% by mass

Hereinafter, the method for producing the base material layer film used in each example and comparative example is described. >Fabrication of substrate film: A-1> Using a single-screw extruder, 80% by mass of PBT resin and 20% by mass of PET resin were mixed. The resulting mixed resin was prepared with an average particle diameter of 2.4 μm as inert particles so that the silica concentration relative to the mixed resin became 900 ppm. The silicon dioxide particles form a mixture. After the resulting mixture is melted at 290°C, the melt line is introduced into a 12-element static mixer. By this, the melted resin is divided and laminated to obtain a multilayer melt composed of the same raw material resin. It was cast from a T-die at 265°C, and was intimately attached to a 15°C cooling roll by an electrostatic adhesion method to obtain an unstretched sheet. Then, roll extension was performed at 2.9 times in MD direction at 60°C. Then, the longitudinally stretched film was forcibly cooled by a cooling roller with a surface temperature set to 25°C, and then passed through a tenter to extend 4.0 times in the TD direction at 90°C and tensioned at 200°C for 3 seconds After heat treatment and 9% of the relaxation in the TD direction for 9% for 1 second, the holding portions at both ends were cut and removed by 10% each to obtain a milling roll of PBT film with a thickness of 15 μm. The film forming conditions, physical properties and evaluation results of the obtained film are shown in Table 1. In the film-forming step of the biaxially stretched film of the base material layer film, after stretching in the MD direction, the resin composition for easy adhesion layer (coating solution 1) is applied by a spray bar coating method. Then, it was dried and introduced into a tenter, and stretched, heat-treated, and relaxed in the TD direction under the above-described film-forming conditions to obtain a laminated film A1 having an easy-adhesion layer formed on one side of a PBT film with a thickness of 15 μm.

>Fabrication of substrate film: A-2> In the aforementioned method of manufacturing the base film A-1, the amount of discharge when casting molten resin from a T-die is adjusted to obtain a PBT film having a thickness of 20 μm. In the film-forming step of the biaxially stretched film of the base material layer film, after stretching in the MD direction, the resin composition for easy adhesion layer (coating solution 1) is applied by a spray bar coating method. Then, it was introduced into a tenter while drying, and stretched, heat-treated, and relaxed in the TD direction under the above-described film-forming conditions to obtain a laminated film A2 having an easy-adhesion layer formed on one side of a PBT film having a thickness of 20 μm.

>Production of substrate layer film: A-3> Using a single-screw extruder, 80% by mass of PBT resin and 20% by mass of PET resin were mixed. The resulting mixed resin was prepared with an average particle diameter of 2.4 μm as inert particles so that the silica concentration relative to the mixed resin became 900 ppm. The silicon dioxide particles form a mixture. After the resulting mixture is melted at 290°C, the melt line is introduced into a 12-element static mixer. By this, the melted resin is divided and laminated to obtain a multilayer melt composed of the same raw material resin. It was cast from a T-die at 265°C, and was intimately attached to a 15°C cooling roll by an electrostatic adhesion method to obtain an unstretched sheet. Then, roll stretching was performed at 3.8 times in the MD direction at 60°C. Then, the longitudinally stretched film is forcibly cooled by a cooling roller with a surface temperature set to 25°C, and then passed through a tenter to be stretched 4.0 times in the TD direction at 90°C and tensioned at 210°C for 3 seconds After the heat treatment and the relaxation treatment in the TD direction of 5% for 1 second, the holding portions at both ends were cut and removed by 10% each to obtain a milling roll of a PBT film with a thickness of 15 μm. The film forming conditions, physical properties and evaluation results of the obtained film are shown in Table 1. In the film-forming step of the biaxially stretched film of the base material layer film, after stretching in the MD direction, the resin composition for easy adhesion layer (coating solution 1) is applied by a spray bar coating method. Then, it was introduced into a tenter while being dried, and stretched, heat-treated, and relaxed in the TD direction under the above-described film-forming conditions to obtain a laminated film A3 having an easy-adhesion layer formed on one side of a 15 μm thick PBT film.

The method of forming the inorganic thin film layer in each example and comparative example is described below. >Formation of a composite oxide of silicon dioxide and aluminum oxide (SiO ₂ /Al ₂ O ₃ ) inorganic thin film layer M1> As the inorganic thin film layer M1, the base film A-1 to the base film A-3 in the examples Use electron beam evaporation to form a composite oxide layer of silica and alumina. As a vapor deposition source, particulate SiO ₂ (purity 99.9%) and A1 ₂ O ₃ (purity 99.9%) of about 3 mm to 5 mm are used. The film thickness of the inorganic thin film layer (SiO ₂ /A1 ₂ O ₃ composite oxide layer) in the film obtained in this way (film containing an inorganic thin film layer/easy adhesion layer) was 13 nm. In addition, the composition of the composite oxide layer is SiO ₂ /A1 ₂ O ₃ (mass ratio)=60/40.

> Formation of Alumina (Al ₂ O ₃ ) Inorganic Thin Film Layer M2> As the inorganic thin film layer M2, aluminum oxide was vapor-deposited on the base layer film A-1 and OOPE of the comparative example. The method of vapor-depositing aluminum oxide on the base material film is to install the film on the winding-out side of a continuous vacuum vapor deposition machine, and travel through a cooling metal cylinder to wind up the film. At this time, the continuous vacuum evaporation machine was depressurized to 10 ^-4 Torr or less, and an aluminum crucible was filled with aluminum 99.99% purity from the lower part of the cooling cylinder to heat and evaporate the metal aluminum. Oxygen is supplied to the aluminum vapor to perform an oxidation reaction, and is deposited on the film while adhering to form an aluminum oxide film with a thickness of 30 nm.

>Formation of protective layer> On the inorganic thin film layer formed on the aforementioned base layer film, the coating liquid 2 was applied by a wire bar coating method, and dried at 200° C. for 15 seconds to obtain a protective layer. The coating amount after drying was 0.19 g/m ² (Dry). The gas-barrier laminated film provided with the easy-adhesion layer/inorganic thin-film layer/protective layer on the base layer film as described above.

>Formation of laminated film> [Example 1] On the base film A-1 prepared above, a coating layer 1 as an easy adhesion layer, M1 as an inorganic vapor-deposited layer, and a coating layer 2 as a protective layer are sequentially deposited to fabricate a gas barrier film. Here, on the protective layer side of the produced gas barrier film, an adhesive ("TM569" manufactured by Toyo-Morton Co., Ltd., hardener "CAT-10L", and ethyl acetate was used at 33.6:4.0:62.4 (Weight ratio) ratio), a polyethylene film with a thickness of 60 μm (“L4102” manufactured by Toyobo Co., Ltd.) as a sealant layer is laminated by a dry lamination method, and is aged at 40° C. for 4 days to obtain The laminated film of Example 1. In addition, the thickness of the adhesive layer formed of the urethane-based two-liquid curing adhesive after drying was all 4 μm.

[Example 2] In the laminated film of Example 1 described above, the base material was A-3, and the sealant layer was an LLDPE film (manufactured by Prime Polymer, Evolue SP2020, thickness 130 μm), except that it was the same as Example 1. Way, the laminated film of Example 2 was obtained. In addition, the thickness of the adhesive layer formed of the urethane-based two-liquid curing adhesive after drying was all 4 μm.

[Example 3] On the base film A-1 prepared above, a coating layer 1 as an easy adhesion layer, M1 as an inorganic vapor-deposited layer, and a coating layer 2 as a protective layer are sequentially deposited to fabricate a gas barrier film. On the protective layer side of the gas barrier film, use a carbamate-based two-liquid curing adhesive ("Takelac (registered trademark) A525S" and "Takenate (registered trademark) A50" manufactured by Mitsui Chemicals Co., Ltd. for 13.5 : 1 (mass ratio) ratio), a dry lamination method is used to bond CPP (“P1147” manufactured by Toyobo Co., Ltd.) with a thickness of 70 μm as a heat-sealing resin layer, and it is aged at 40°C for 4 days. This obtained the laminated film of Example 3. In addition, the thickness of the adhesive layer formed of the urethane-based two-liquid curing adhesive after drying was all 4 μm.

[Example 4] In the laminate film of Example 3 described above, the laminate film of Example 4 was obtained in the same manner as in Example 1 except that the base film was A-2. In addition, the thickness of the adhesive layer formed of the urethane-based two-liquid curing adhesive after drying was all 4 μm.

[Example 5] On the base film A-1 obtained above, a carbamate-based two-liquid curing adhesive ("Takelac (registered trademark) A525S" manufactured by Mitsui Chemicals Co., Ltd. and "Takenate (registered trademark) A50" was used ”Prepared at a ratio of 13.5:1 (mass ratio)), dry laminating aluminum foil (8079 material, thickness 7 μm) to produce a substrate film/aluminum foil laminate. Next, on the aluminum foil side of the base film/aluminum foil laminate obtained above, using the same adhesive as above, a 50 μm thick CPP (“P1147” manufactured by Toyobo Co., Ltd.) was laminated as a heat-sealing resin layer. The laminated film of Example 5 was obtained by performing aging at 40°C for 4 days. The thickness of the adhesive layer formed of the urethane-based two-liquid curing adhesive was 4 μm after drying.

[Example 6] In the laminated film of Example 5 described above, the heat-sealable resin layer was a non-stretched polypropylene film with a thickness of 60 μm (“P1147” manufactured by Toyobo Co., Ltd.), except that it was the same as Example 5. To obtain the laminated film of Example 6. The thickness of the adhesive layer formed of the urethane-based two-liquid curing adhesive was 4 μm after drying.

[Comparative Example 1] In the laminated film of Example 1 described above, the inorganic vapor deposition layer is M2, and the sealant layer is a polyethylene film ("L4102" manufactured by Toyobo Co., Ltd.) with a thickness of 40 μm. 1 In the same manner, the laminated film of Comparative Example 1 was obtained.

[Comparative Example 2] In the laminated film of Comparative Example 1 described above, except that the base material film is 12 μm thick OPET (“E5102” manufactured by Toyobo Co., Ltd.), and in the same manner as Comparative Example 1, the comparative example 2 was obtained. Laminated film.

[Comparative Example 3] On the ONy (“N1102” manufactured by Toyobo Co., Ltd.) with a thickness of 15 μm as a base film, an adhesive (“TM569” manufactured by Toyo-Morton Co., Ltd., hardener “CAT-10L”, ethyl acetate The ester is formulated at a ratio of 33.6:4.0:62.4 (mass ratio), and a polyethylene film (“L4102” manufactured by Toyobo Co., Ltd.) with a thickness of 60 μm is applied as a sealant layer by dry lamination at 40° C. After aging for 4 days, the laminated film of Comparative Example 3 was obtained. In addition, the thickness of the adhesive layer formed of the urethane-based two-liquid curing adhesive after drying was all 4 μm.

[Comparative Example 4] On the ONy (“N1102” manufactured by Toyobo Co., Ltd.) with a thickness of 15 μm as a base film, an adhesive (“TM569” manufactured by Toyo-Morton Co., Ltd., hardener “CAT-10L”, ethyl acetate The ester was formulated at a ratio of 33.6:4.0:62.4 (mass ratio), and the LLDPE film (manufactured by Prime Polymer, Evolue SP2020, thickness 130 μm) was applied as a sealant layer by dry lamination, and aged at 40°C for 4 days. By this, the laminated film of Comparative Example 4 was obtained. In addition, the thickness of the adhesive layer formed of the urethane-based two-liquid curing adhesive after drying was all 4 μm.

[Comparative Example 5] In the laminated film of Comparative Example 2 described above, the adhesive was set as a urethane-based two-liquid curing adhesive ("Takelac (registered trademark) A525S" manufactured by Mitsui Chemicals Co., Ltd. and "Takenate (registered trademark ) A50” is formulated at a ratio of 13.5:1 (mass ratio), and the heat-sealing resin layer is a non-stretching polypropylene film with a thickness of 70 μm (“P1147” manufactured by Toyobo Co., Ltd.). In the same manner as in Comparative Example 2, the laminated film of Comparative Example 5 was obtained.

[Comparative Example 6] In the laminated film of Comparative Example 3 described above, the adhesive was set as a urethane-based two-liquid curing adhesive ("Takelac (registered trademark) A525S" manufactured by Mitsui Chemicals Co., Ltd. and "Takenate (registered trademark ) A50” is formulated at a ratio of 13.5:1 (mass ratio), and the heat-sealing resin layer is a non-stretching polypropylene film with a thickness of 70 μm (“P1147” manufactured by Toyobo Co., Ltd.). In the same manner as in Comparative Example, the laminated film of Comparative Example 6 was obtained.

[Reference Example 1] As a base film, OPEN (“E5102” manufactured by Toyobo Co., Ltd.) with a thickness of 12 μm was used as a base film, and an adhesive (“TM569” manufactured by Toyo-Morton Co., Ltd. and a curing agent “CAT- 10L”, ethyl acetate is mixed at a ratio of 33.6:4.0:62.4 (mass ratio)) ONy (“N1102” manufactured by Toyobo Co., Ltd.) with a thickness of 15 μm is laminated by a dry lamination method to obtain an OPET/ONy laminate film . To the ONy side of the OPEN/ONy laminate obtained above, an adhesive (“TM569” manufactured by Toyo-Morton Co., Ltd., hardener “CAT-10L”, ethyl acetate was used at 33.6:4.0:62.4 (mass ratio ) Ratio), a polyethylene film (“L4102” manufactured by Toyobo Co., Ltd.) with a thickness of 40 μm is laminated as a sealant layer, and aged at 40° C. for 4 days to obtain a laminate film of Reference Example 1. In addition, the thickness of the adhesive layer formed of the urethane-based two-liquid curing adhesive after drying was all 4 μm.

[Reference Example 2] In Reference Example 1 described above, the laminated film of Reference Example 2 was obtained in the same manner as Reference Example 1 except that the sealant layer was an LLDPE film (produced by Prime Polymer, Evolue SP2020, thickness 130 μm).

[Reference Example 3] In the above Reference Example 2, the adhesive was set as a carbamate-based two-liquid hardening adhesive ("Takelac (registered trademark) A525S" and "Takenate (registered trademark) A50" manufactured by Mitsui Chemicals Co., Ltd.) It is prepared at a ratio of 13.5:1 (mass ratio)), and the heat-sealing resin layer is a non-stretching polypropylene film with a thickness of 70 μm (“P1147” manufactured by Toyobo Co., Ltd.). In the same manner, the laminated film of Reference Example 3 was obtained.

[Reference Example 4] As a base film, OPEN (“E5102” manufactured by Toyobo Co., Ltd.) with a thickness of 12 μm was used as a base film, and an adhesive (“TM569” manufactured by Toyo-Morton Co., Ltd. and a curing agent “CAT- 10L”, ethyl acetate is prepared at a ratio of 33.6:4.0:62.4 (mass ratio), and ONy (“N1102” manufactured by Toyobo Co., Ltd.) with a thickness of 15 μm is laminated by a dry lamination method to obtain an OPET/ONy laminate body. Then, on the ONy side of the OPEN/ONy laminate obtained above, a carbamate-based two-liquid curing adhesive ("Takelac (registered trademark) A525S" manufactured by Mitsui Chemicals Co., Ltd. and "Takenate (registered Trademark) A50” is prepared at a ratio of 13.5:1 (mass ratio)), dry-laminated aluminum foil (8079 material, thickness 7 μm) to produce an OPET/ONy/aluminum foil laminate. Next, on the aluminum foil side of the OPEN/ONy/aluminum foil laminate obtained above, using the same adhesive as above, a non-stretching polypropylene film (“P1147” manufactured by Toyobo Co., Ltd.) with a thickness of 50 μm was bonded as a heat sealability. The resin layer was aged at 40°C for 4 days to obtain the laminated film of Reference Example 4. The thickness of the adhesive layer formed of the urethane-based two-liquid curing adhesive was 4 μm after drying.

The evaluation results of the laminated films obtained in Examples, Comparative Examples and Reference Examples are shown in Table 1, Table 2 and Table 3.

[Table 2]

[table 3]

[Table 4]

As shown in Table 1, the laminated films of Examples 1 to 6 obtained by the present invention can have a base film as one layer, so the amount of packaging material can be reduced, and 9.0N as an excellent puncture strength can be obtained As described above, the pinhole resistance is excellent, and the self-supporting bag made of the laminated film can ensure sufficient self-sustainability.

On the other hand, in Comparative Example 1, since the values of the thickness of the laminated film and the ring stiffness are not within the scope of the present invention, the self-supporting property of the self-supporting pouch produced was insufficient. In Comparative Example 2, only the previous OPET film was used as the base material layer, and therefore the puncture strength and pinhole resistance were poor. In addition, since the numerical value of the ring stiffness does not satisfy the scope of the present invention, the self-supporting property as a self-supporting bag is also insufficient. In Comparative Example 3, only the previous ONy was used as the base layer. Therefore, although the puncture strength and pinhole resistance were good, the value of the ring stiffness did not satisfy the range of the present invention, so the self-supporting property as a self-supporting bag was insufficient. In Comparative Example 4 and Comparative Example 6, only the previous ONy was used as the base material layer, so the puncture strength and pinhole resistance were good. In addition, by increasing the thickness of the sealant layer, the value of the ring stiffness becomes higher, and it has good self-reliance. However, the base film is different from the present invention, and as a result, the puncture strength after the cooking treatment is significantly reduced. In Comparative Example 5, by increasing the thickness of the sealant layer, the value of the ring stiffness was high, and the self-standing property of the self-supporting bag was improved. However, since OPET was used as the base material layer, the result was poor puncture strength and pinhole resistance.

Reference Examples 1 to 4 show the evaluation results when they are excellent in impact resistance or puncture resistance, and can also be used for a substrate film in the case of laminating OPET and ONy which are resistant to heat treatment such as cooking treatment. If the reference example is compared with the example, the laminated film of the present invention of the example has the same performance as the laminated film using two layers of OPEN and ONy as the substrate layer, although the substrate layer is one layer. [Industry availability]

According to the present invention, a laminated film can be obtained, which can reduce the amount of packaging materials, has excellent bag-breaking resistance, and can ensure sufficient self-reliability when used as a stand-up bag, and is suitable for liquid packaging of cooked food and the like. According to the present invention, it is possible to provide a laminated film which is excellent in puncture strength even after being subjected to wet heat treatment, and has bag-breaking resistance and bending resistance. Since the self-standing pouches and other packaging bags previously made with the laminated film of the base film formed by stacking OPET and ONy can be changed to a laminated film composed of a single base film, it can be widely used Food packaging materials.

1: Storage Department 2: Side seal 3: Top seal 4: bottom 5: Length 6: Width 7: Fold in at the bottom

FIG. 1 is a plan view showing the shape of a self-standing pouch produced using the laminated film of the present invention. Fig. 2 is a perspective view showing the shape of a self-standing pouch produced using the laminated film of the present invention.

no.

Claims (10)

A laminated film composed of at least a substrate layer and a sealant layer; (a) The base material layer is a biaxially stretched polyester film with a thickness of 9 μm to 25 μm containing 70% by mass or more of polybutylene terephthalate; (b) The puncture strength of the laminated laminate film is 9.0N or more; (c) The value X of the ring stiffness of the laminated film is 80 mN/25 mm or more; (e) The total thickness is 59 μm to 160 μm. The laminated film according to claim 1, wherein the base material layer has an inorganic thin film layer on at least one side. The laminated film according to claim 2, wherein the inorganic thin film layer is a layer composed of oxides of silicon oxide and/or aluminum oxide. The laminated film according to claim 2 or 3, wherein an adhesive layer is provided between the base material layer and the inorganic thin film layer. The laminated film according to claim 2 or 3, which has a protective layer on the inorganic thin film layer. A packaging bag composed of the laminated film as described in any one of claims 1 to 5. The packaging bag as described in claim 6 is used as a stand-up bag. The packaging bag as described in claim 7, wherein when the value of the ring stiffness of the laminated film is X, the content Y of the self-supporting bag satisfies the following formula (1), and the unit of the content Y is g; 1.8X≦Y≦3.8X Formula (1). The packaging bag as described in any one of claims 6 to 8 is used for cooking. The packaging bag described in any one of claims 6 to 8 is used for heating in a microwave oven.

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