JP7443726B2 - Laminated film and packaging bags - Google Patents

Description

The present invention relates to a laminated film and a packaging bag for manufacturing a packaging bag that is sealed by thermally welding thermoplastic resin layers together.

A laminated film in which a thermoplastic resin layer and a gas barrier film layer are bonded together by an adhesive layer is formed into a packaging bag for storing foods, medicines, etc. by thermally welding the thermoplastic resin layers together (for example, Patent Document 1 ). For packaging bags that require microwave heating and high environmental compatibility, a structure in which an inorganic oxide film is applied to the gas barrier film layer is being actively adopted, instead of the above-mentioned structure in which aluminum foil is applied to the gas barrier film layer. There is. As a technique for increasing the adhesion between the thermoplastic resin layer and the inorganic oxide film, it has been proposed to specify the grafting rate of maleic anhydride graft polymerized polypropylene contained in the adhesive layer (see, for example, Patent Document 2). ).

Japanese Patent Application Publication No. 2011-46006 Japanese Patent Application Publication No. 06-306198

By the way, packaging bags that are subjected to high-temperature sterilization while containing foods, medicines, etc., have a heat-welded part between thermoplastic resin layers that has resistance to peeling after sterilization, so-called retort resistance. Desired. In particular, packaging bags that contain liquid seasonings such as vinegar and oil, and bath additives containing alcohol require higher retort resistance because the contents contain volatile substances with high penetration power. . On the other hand, when packaging bags manufactured by thermal welding of laminated films are subjected to high-temperature sterilization treatment, the polypropylene crystallizes and the interface between the crystalline and amorphous parts decreases the bag drop resistance. The formation of microcracks progresses.

An object of the present invention is to provide a laminated film and a packaging bag that can improve resistance to falling bags after sterilization treatment.

A laminated film for solving the above problems includes a gas barrier film layer, a thermoplastic resin layer, and an adhesive layer located between the gas barrier film layer and the thermoplastic resin layer, and the thermoplastic resin layer This is a laminated film for a packaging bag, in which the thermoplastic resin layers are overlapped so as to face each other and sealed by thermal welding of the thermoplastic resin layers. The main component of the adhesive layer is maleic anhydride graft polymerized polypropylene, and the thermoplastic resin layer includes a polypropylene resin and an incompatible component that is incompatible with the polypropylene resin. In the non-thermal welding part of the packaging bag, the content of the soluble component is 1% by mass or more and 40% by mass with respect to the total amount of the thermoplastic resin layer, and is sterilized at a temperature of 80° C. or more and 130° C. or less, Conditions 1 and 2 below are satisfied. Condition 1 is that the maximum impact energy according to JIS K 7211-2:2006 is 0.45 J or more. Condition 2 is that the mode of destruction is penetration in accordance with JIS K 7211-1:2006.

As mentioned above, crystallization of polypropylene after sterilization causes a decrease in the adhesive strength between the adhesive layer and the gas barrier film layer and a decrease in cohesive force in the thermoplastic resin layer, resulting in bags falling into packaging bags. It reduces tolerance. Identifying the materials that make up the adhesive layer and the materials that make up the thermoplastic resin layer make it possible to increase the adhesion between the gas barrier film layer and the thermoplastic resin layer before sterilization. However, there is still room for improvement in increasing the resistance to falling bags after sterilization.

In this regard, the present inventors have found that the maximum impact force energy in the non-thermal welded portion and the mode of destruction have a close relationship with the result of bag drop resistance after sterilization treatment. The above-mentioned laminated film is determined according to JIS K 7211-2 of the non-thermal welded part after sterilization treatment, using the relationship between maximum impact energy and bag drop resistance, and the relationship between the mode of destruction and bag drop resistance. The maximum impact force energy according to JIS K 7211-1:2006 shall be 0.45 J or more, and the mode of failure shall be penetration according to JIS K 7211-1:2006. Therefore, it becomes possible to improve resistance to dropping bags after sterilization treatment.

In the laminated film, the grafting rate of maleic anhydride in the maleic anhydride graft polymerized polypropylene may be 0.1% by mass or more and 1% by mass or less. According to this configuration, since the graft ratio is 0.1% by mass or more, sufficient adhesive strength can be obtained, and delamination after sterilization treatment can be suppressed. Moreover, since the grafting ratio is 1% by mass or less, the resin properties of the maleic anhydride graft polymerized polypropylene are stabilized.

In the laminated film, the gas barrier film layer includes a base film layer, a barrier layer located between the base film layer and the adhesive layer, and a barrier layer located between the base film layer and the barrier layer. and a metal oxide layer located between the primer layer and the barrier layer. The materials constituting the barrier layer include a condensate of a metal alkoxide, a condensate of a hydrolysis product of a metal alkoxide, a condensate of an alkoxysilylalkyl isocyanurate, and a coating film of a water-soluble polymer having a hydroxyl group. It may also contain any one selected from the group consisting of dried products.

In the laminated film, the gas barrier film layer includes a base film layer, a barrier layer located between the base film layer and the adhesive layer, and a barrier layer located between the base film layer and the barrier layer. and a metal oxide layer located between the primer layer and the barrier layer. The primer layer may include a reaction product of either trialkoxysilane or a hydrolysis product of trialkoxysilane, an acrylic polyol, and an isocyanate compound.

In the laminated film, the gas barrier film layer includes a base film layer including a plasma-treated surface, a barrier layer, and a metal oxide layer located between the surface of the base film layer and the barrier layer. may be provided.

In the laminated film, the gas barrier film layer includes a base film layer, a barrier layer located between the base film layer and the adhesive layer, and the barrier layer containing a polycarboxylic acid polymer. , may be provided.

In the above laminated film, the gas barrier film layer is a base film layer and a barrier layer located between the base film layer and the adhesive layer, and is a barrier layer formed of a hydrolysis product of a metal oxide and a phosphorus compound. The barrier layer may include the barrier layer.

A packaging bag for solving the above problems is a packaging bag in which thermoplastic resin layers of a laminated film are overlapped so as to face each other and sealed by thermal welding of the thermoplastic resin layers, the laminated film is the above-mentioned laminated film.

According to each of the above configurations, it is possible to increase the effectiveness of improving resistance to dropped bags after sterilization treatment.
A packaging bag for solving the above problems includes a gas barrier film layer, a thermoplastic resin layer, and an adhesive layer located between the gas barrier film layer and the thermoplastic resin layer, and the thermoplastic resin layer The packaging bag is stacked so that the thermoplastic resin layers face each other and sealed by thermal welding of the thermoplastic resin layers. The main component of the adhesive layer is maleic anhydride graft polymerized polypropylene, and the thermoplastic resin layer includes a polypropylene resin and an incompatible component that is incompatible with the polypropylene resin. The content of the solution component is 1% by mass or more and 40% by mass based on the total amount of the thermoplastic resin layer. and in the thermally welded portion of the packaging bag that has been sterilized at a temperature of 80° C. or higher and 130° C. or lower, the maximum peel strength of the thermally welded portion that is the edge of the packaging bag is 28 N/15 mm or higher; In addition, the following condition 3 or the following condition 4 is satisfied. In condition 3, the peel strength has a stable region after the maximum value is obtained, and the ratio of the peel strength to the maximum value in the stable region is 0.3 or more. In Condition 4, the peel strength does not have the stable range, and the ratio of the average peel strength to the maximum value after the maximum value is obtained is 0.3 or more.

As mentioned above, specifying the material constituting the adhesive layer and specifying the material constituting the thermoplastic resin layer is to increase the adhesion between the gas barrier film layer and the thermoplastic resin layer before sterilization treatment. However, there is still room for improvement in terms of increasing resistance to dropping bags after sterilization. The present inventors tested the peel strength of the heat-welded part after sterilization, and found that the peel strength after the maximum peel strength was obtained was closely related to the result of drop bag resistance after sterilization. We found that there is a strong relationship between Then, using the relationship between the peel strength after the maximum peel strength is obtained and the bag drop resistance, the laminated film has the maximum peel strength in a stable range after the maximum value is obtained. The ratio to the value shall be 0.3 or more. Furthermore, the laminated film satisfies the requirement that the ratio of the average peel strength to the maximum value after the maximum value is obtained to the end point is 0.3 or more. Therefore, it becomes possible to improve resistance to dropping bags after sterilization treatment.

According to the present invention, resistance to falling bags after sterilization treatment can be improved.

FIG. 3 is a cross-sectional view showing the structure of a laminated film having a first layer configuration. FIG. 3 is a cross-sectional view showing the structure of a laminated film having a second layer configuration. FIG. 3 is a cross-sectional view showing the structure of a laminated film having a third layer configuration. FIG. 3 is a cross-sectional view showing the structure of a laminated film having a fourth layer configuration. FIG. 2 is a plan view of a packaging bag for explaining a method of manufacturing the packaging bag. FIG. 2 is a plan view of a packaging bag for explaining a method of manufacturing the packaging bag. FIG. 2 is a plan view of a packaging bag for explaining a method of manufacturing the packaging bag. The perspective view which shows the test piece used for the measurement of peel strength. FIG. 2 is a perspective view showing the end of a test piece during peel strength measurement. A graph showing an example of the relationship between peel strength and tensile distance. A graph showing another example of the relationship between peel strength and tensile distance.

An embodiment of a laminated film and a packaging bag will be described with reference to FIGS. 1 to 11.
Note that FIG. 1 shows a cross-sectional structure of a laminated film having a first layer structure, and FIG. 2 shows a cross-sectional structure of a laminated film having a second layer structure.

Further, FIG. 3 shows a cross-sectional structure of a laminated film having a third layer structure, and FIG. 4 shows a cross-sectional structure of a laminated film having a fourth layer structure.
(1st layer configuration)
As shown in FIG. 1, the laminated film 10 includes a gas barrier film layer 11, an adhesive layer 12, and a thermoplastic resin layer 13. Adhesive layer 12 is located between gas barrier film layer 11 and thermoplastic resin layer 13. The adhesive layer 12 is in contact with the gas barrier film layer 11 and the thermoplastic resin layer 13. The gas barrier film layer 11 and the thermoplastic resin layer 13 are bonded together by an adhesive layer 12.

The laminated film 10 is stacked so that one part of the thermoplastic resin layer 13 faces the other part, or one part of the thermoplastic resin layer 13 and one part of the thermoplastic resin layer 13 of another laminated film 10 are stacked. The thermoplastic resin layers 13 are stacked so as to face each other, and a packaging bag is formed by thermally welding the thermoplastic resin layers 13 together. The packaging bag is sterilized at a temperature of 80°C or higher and 130°C or lower. The non-thermal welded portion in the packaging bag after sterilization satisfies Conditions 1 and 2 below.

(Condition 1) The maximum impact energy according to JIS K 7211-2:2006 is 0.45 J or more. The energy carrier is the mass of the weight plus the mass of the striker.

(Condition 2) The mode of destruction is penetration in accordance with JIS K 7211-1:2006.
The heat welded part in the packaging bag after sterilization has a maximum peel strength of 28 N/15 mm or more when continuously measuring the peel strength from the start point to the end point of the heat welded part, and under the following conditions 3. Or, the following condition 4 is satisfied.

(Condition 3) The peel strength has a stable region after the maximum value is obtained, and the ratio of the peel strength to the maximum value in the stable region is 0.3 or more.
(Condition 4) The peel strength does not have a stable range, and after the maximum value is obtained, the ratio of the average peel strength to the maximum value from the time when the maximum value is obtained to the maximum value is 0.3 or more.

[Gas barrier film layer 11]
As shown in FIG. 1, the gas barrier film layer 11 includes a base film layer 11a, a primer layer 11b, a metal oxide layer 11c, and a barrier layer 11d. Primer layer 11b is located between base film layer 11a and barrier layer 11d. The metal oxide layer 11c is located between the primer layer 11b and the barrier layer 11d. The barrier layer 11d is located between the base film layer 11a and the adhesive layer 12. The base film layer 11a and the metal oxide layer 11c are joined by a primer layer 11b.

[Base film layer 11a]
The base film layer 11a has a single layer structure made of one resin film or a laminated structure made of two or more resin films. The thickness of the base film layer 11a can be changed as appropriate depending on the various resistances and processability required of the packaging bag, and is, for example, 3 μm or more and 200 μm or less. From the viewpoint of increasing the flexibility of the packaging bag, the thickness of the base film layer 11a is preferably 6 μm or more and 30 μm or less.

The materials constituting the resin film are, for example, polyester resins, polyolefin resins, polyamide resins, and hydroxyl group-containing polymers. Examples of the polyester resin include polyethylene terephthalate, polyethylene naphthalate, polyethylene-2,6-naphthalate, polybutylene terephthalate, and copolymers thereof. Polyolefin resins are polyethylene and polypropylene. Examples of the polyamide resin include nylon-6, nylon-66, and nylon-12. Examples of the hydroxyl group-containing polymer include polyvinyl alcohol and ethylene-vinyl alcohol copolymer. The material constituting the resin film may be one of polyolefin resins, polyamide resins, and hydroxyl group-containing polymers, or a combination of two or more thereof.

The resin film may be a stretched film or a non-stretched film. From the viewpoint of excellent mechanical strength and dimensional stability, it is preferable that the resin film is a stretched film. The stretched film is a uniaxially stretched film or a biaxially stretched film.

[Primer layer 11b]
The primer layer 11b has various adhesion functions such as a chemical adsorption function and an anchor function, and improves the adhesion between the base film layer 11a and the metal oxide layer 11c. The material constituting the primer layer 11b includes, for example, a reaction product of either trialkoxysilane or a hydrolysis product of trialkoxysilane, an acrylic polyol, and an isocyanate compound.

Trialkoxysilanes are represented by the general formula R ¹ Si(OR ² ) ₃ . R ¹ is an alkyl group, a vinyl group, an alkyl group containing an isocyanate group, an alkyl group containing a glycidoxy group, or an alkyl group having an epoxy group. The alkyl group contained in R ¹ may be a linear alkyl group, a branched alkyl group, or a cyclic alkyl group. R ¹ can be changed as appropriate depending on the materials constituting the base film layer 11a and the metal oxide layer 11c. OR ² is a hydrolyzable alkoxy group such as a methoxy group, an ethoxy group, or an ethoxymethoxy group. The hydrolysis product of trialkoxysilane can be obtained, for example, by adding an acid or an alkali to trialkoxysilane and hydrolyzing the trialkoxysilane. As the trialkoxysilane, one kind selected from the above-mentioned ones can be used alone, or two or more kinds can be used in combination.

Trialkoxysilanes are, for example, ethyltrimethoxysilane, vinyltrimethoxysilane, isocyanatepropyltriethoxysilane, γ-isocyanatepropyltrimethoxysilane, glycidoxypropyltrimethoxysilane, and epoxycyclohexylethyltrimethoxysilane. Among these, preferred trialkoxysilanes are isocyanatepropyltriethoxysilane and γ-isocyanatepropyltrimethoxysilane containing an isocyanate group. Further, the trialkoxysilane is preferably glycidoxytrimethoxysilane having a glycidoxy group or epoxycyclohexylethyltrimethoxysilane having an epoxy group.

Acrylic polyol is a polymer compound obtained by polymerizing acrylic acid derivative monomers alone or a polymer compound obtained by copolymerizing acrylic acid derivative monomers. The polymer compound obtained by copolymerizing acrylic acid derivative monomers includes a compound having a hydroxyl group at the end and reacting with the isocyanate group of the isocyanate compound. Acrylic acid derivative monomers are, for example, ethyl methacrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, and hydroxybutyl methacrylate. The monomer other than the acrylic acid derivative monomer is, for example, styrene.

The acrylic polyol is preferably a homopolymer of one type of acrylic acid derivative monomer selected from the group consisting of ethyl methacrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, and hydroxybutyl methacrylate. Alternatively, the acrylic polyol is preferably a copolymer of styrene and an acrylic acid derivative monomer selected from the group described above. As the acrylic polyol, one kind selected from the above-mentioned ones can be used alone, or two or more kinds can be used in combination.

The hydroxyl value of the acrylic polyol is preferably 5 KOHmg/g or more and 200 KOHmg/g or less. This increases the reactivity between the acrylic polyol and the isocyanate compound. The ratio (MA/MO) of the mass (MA) of the acrylic polyol to the mass (MO) of the trialkoxysilane is preferably 1/1 or more and 100/1 or less, and 2/15 or more and 50/1 or less. It is more preferable that there be.

The isocyanate compound has two or more isocyanate groups and forms a urethane bond by reacting with an acrylic polyol. The isocyanate compound functions as a crosslinking agent or a curing agent for increasing the adhesion between the base film layer 11a and the metal oxide layer 11c.

The isocyanate compound is, for example, an aromatic isocyanate compound or an aliphatic isocyanate compound. Further, the isocyanate compound is, for example, a polymer having an isocyanate group obtained by polymerizing an aromatic isocyanate compound or an aliphatic isocyanate compound and a polyol. Further, the isocyanate compound is an aromatic isocyanate compound, an aliphatic isocyanate compound, and a derivative of the above-mentioned polymer having an isocyanate group. As the isocyanate compound, one type selected from those mentioned above can be used alone, or two or more types can be used in combination.

Examples of the aromatic isocyanate compound include tolylene diisocyanate and diphenylmethane diisocyanate. Examples of the aliphatic isocyanate compounds include xylene diisocyanate and hexalenediisocyanate.

The ratio (NI/NH) of the number of isocyanate groups (NI) derived from the isocyanate compound to the number (NH) of hydroxyl groups derived from the acrylic polyol is, for example, 50 times or less. The number of hydroxyl groups derived from the acrylic polyol is, for example, equal to the number of isocyanate groups derived from the isocyanate compound. This prevents insufficient curing of the primer layer 11b due to too little isocyanate compound, or blocking that occurs due to too much isocyanate compound, making processing of laminated film 10 difficult.

The reaction product constituting the primer layer 11b is obtained by reacting either trialkoxysilane or a hydrolysis product of trialkoxysilane, an acrylic polyol, and an isocyanate compound in a solvent.

The solvent may be used as long as it can dissolve and dilute each component. Examples of solvents include esters, alcohols, ketones, and aromatic hydrocarbons. Examples of esters include ethyl acetate and butyl acetate. Examples of alcohols include methanol, ethanol, and isopropyl alcohol. Ketones are, for example, methyl ethyl ketone. Examples of aromatic hydrocarbons include toluene and xylene. As the solvent, one type selected from the above-mentioned solvents can be used alone, or two or more types can be used in combination.

Note that a catalyst may be used to promote the reaction between the trialkoxysilane and the acrylic polyol when producing the reaction product constituting the primer layer 11b. From the viewpoint of increasing reactivity and obtaining polymerization stability, the catalyst is preferably a tin compound such as tin chloride, tin oxychloride, and tin alkoxide. The catalyst may be added directly to the reaction solution at the time of blending each component, or may be added to the reaction solution after being dissolved in a solvent such as methanol.

Further, in producing the reaction product constituting the primer layer 11b, a metal alkoxide or a hydrolysis product of the metal alkoxide may be used to increase the stability of the liquid containing the reaction product. The metal atoms constituting the metal alkoxide are Si, Al, Ti, or Zr. From the viewpoint of stably existing in an aqueous solvent, the metal alkoxide is preferably tetraethoxysilane, tripropoxyaluminum, or a mixture thereof. The hydrolysis product of metal alkoxide is obtained by the same method as the method for obtaining the hydrolysis product of trialkoxysilane. The metal alkoxide hydrolysis product may be produced simultaneously with the trialkoxysilane hydrolysis product, or may be produced separately from the trialkoxysilane hydrolysis product.

Further, the primer layer 11b may contain various additives. Additives are, for example, curing accelerators, antioxidants, leveling agents, flow regulators, catalysts, crosslinking reaction promoters, and fillers. Examples of the curing accelerator include tertiary amines, imidazole derivatives, carboxylic acid metal salt compounds, quaternary ammonium salts, and quaternary phosphonium salts. Examples of antioxidants include phenolics, sulfurs, and phosphites.

One example of a method for forming the primer layer 11b is to add an acrylic polyol and an isocyanate compound to a solution obtained by hydrolyzing trialkoxysilane or a solution obtained by hydrolyzing trialkoxysilane together with a metal alkoxide in the presence of a catalyst. Mix to form a coating fluid. Next, the primer layer 11b is formed by applying a coating liquid to the base film layer 11a and drying the coating film.

Another example of the method for forming the primer layer 11b is to add and mix an isocyanate compound to a liquid mixture of trialkoxysilane and acrylic polyol in a solvent where a catalyst and a metal alkoxide are present. Alternatively, after mixing trialkoxysilane and acrylic polyol in a solvent containing a catalyst and a metal alkoxide, a hydrolysis reaction is further performed, and an isocyanate compound is added to the solution after the hydrolysis reaction to form a coating solution. generate. Next, the primer layer 11b is formed by applying a coating liquid to the base film layer 11a and drying the coating film.

In addition, the method of applying the coating liquid is, for example, dipping method, roll coating, gravure coating, reverse coating, air knife coating, comma coating, die coating, screen printing method, spray coating, and gravure offset method.

Further, the method for drying the coating film may be any method as long as it vaporizes solvent molecules by heating the coating liquid. Methods for drying the coating film include, for example, hot air drying, hot roll drying, high frequency irradiation, infrared irradiation, and ultraviolet irradiation. Two or more of the above-mentioned methods may be used to dry the coating liquid.

[Metal oxide layer 11c]
The metal oxide layer 11c is made of metal oxide. Metal oxides are, for example, silicon oxide and aluminum oxide. Preferably, the metal oxide is aluminum oxide. A method for forming the metal oxide layer 11c is, for example, a vacuum evaporation method or a sputtering method.

The thickness of the metal oxide layer 11c is preferably 10 nm or more and 50 nm or less, more preferably 15 nm or more and 30 nm or less. When the thickness of the metal oxide layer 11c is 10 nm or more, the barrier properties of the metal oxide layer 11c are sufficiently ensured. By setting the thickness of the metal oxide layer 11c to 50 nm or less, the transparency of the metal oxide layer 11c and, by extension, the transparency of the laminated film 10 and the packaging bag are ensured.

[Barrier layer 11d]
The material constituting the barrier layer 11d includes any one selected from the group consisting of a condensate of a metal alkoxide, a condensate of a hydrolysis product of a metal alkoxide, and a condensate of an alkoxysilylalkyl isocyanurate.

The metal alkoxide is, for example, an alkoxysilane such as tetraalkoxysilane, alkyltrialkoxysilane, dialkyldialkoxysilane. The alkoxy group is, for example, a methoxy group, an ethoxy group, or an ethoxymethoxy group. The alkoxysilylalkyl isocyanurate is, for example, 1,3,5-tris(3-trialkoxysilylalkyl)isocyanurate.

The barrier layer 11d is formed by applying a coating liquid containing a mixture of a metal alkoxide or a hydrolysis product of a metal alkoxide, a polymer containing vinyl alcohol, an isocyanate compound, and a silane coupling agent, for example, Obtained by drying the coating solution. Polymers containing vinyl alcohol are, for example, polyvinyl alcohol, polyvinyl acetate, and ethylene-vinyl acetate copolymers. The isocyanate compound is, for example, an aromatic isocyanate compound, such as tolylene diisocyanate and xylylene diisocyanate.

Silane coupling agents are represented by the general formula R ³ Si(OR ⁴ ) ₃ . R ³ is an organic functional group, and OR ⁴ is a hydrolyzable alkoxy group such as a methoxy group, an ethoxy group, or an ethoxymethoxy group. Examples of the silane coupling agent include an epoxy silane coupling agent, an amine silane coupling agent, a vinyl silane coupling agent, and an acrylic silane coupling agent. Note that a silane coupling agent having an isocyanate group may be used as a compound serving as both an isocyanate compound and a silane coupling agent.

When the barrier layer 11d is analyzed using a time-of-flight secondary ion mass spectrometer (TOF-SIMS), components derived from alkoxysilane, components derived from a polymer containing vinyl alcohol, and components derived from isocyanate compounds are detected. components and components derived from the silane coupling agent are detected. Note that TOF-SIMS is a surface analysis method that measures the mass spectrum of secondary ions generated when ions are irradiated onto the surface of an analysis target, and can obtain information about the constituent elements and chemical structure of the surface of the analysis target. It is.

The barrier layer 11d contains clay minerals, stabilizers, colorants, viscosity modifiers, etc. in consideration of adhesion with layers adjacent to the barrier layer 11d, wettability, and suppression of cracks due to shrinkage. Additives may be added. Clay minerals may be, for example, colloidal silica and smectite.

The thickness of the barrier layer 11d is preferably 0.01 μm or more and 50 μm or less. When the thickness of the barrier layer 11d is 0.01 μm or more, the gas barrier properties of the barrier layer 11d can be improved. When the barrier layer 11d has a thickness of 50 μm or less, cracks can be suppressed from forming in the barrier layer 11d.

One method for forming the barrier layer 11d is to first mix a metal alkoxide or a hydrolysis product of a metal alkoxide, a polymer containing vinyl alcohol, an isocyanate compound, and a silane coupling agent in a solvent. A coating solution is prepared by: Next, a coating liquid is applied to a base such as the metal oxide layer 11c, and the coating film is dried to form a barrier layer 11d. Since metal alkoxides are difficult to disperse uniformly in aqueous solvents, it is preferable to use hydrolyzed metal alkoxides. As the method for forming the coating film and the method for drying the coating film, methods that can be used for forming the primer layer 11b can be used.

In addition, the laminated film 10 may form an ink layer between the gas barrier film layer 11 and the adhesive layer 12. The ink for forming the ink layer may be an ink containing a colored pigment or may be an ink containing no colored pigment. Inks that do not contain colored pigments are, for example, mediums and varnishes. Ink solvents include, for example, esters, alcohols, ketones, and aromatic hydrocarbons. Esters are, for example, ethyl acetate and butyl acetate. Examples of alcohols include methanol, ethanol, and isopropyl alcohol. Ketones are, for example, methyl ethyl ketone. Aromatic hydrocarbons are, for example, toluene and xylene. The solvent may be one type of solvent or a mixture of two or more types of solvents. Note that from the viewpoint of reducing VOC (Volatile Organic Compounds), an aqueous solvent is preferable.

Printing methods for forming the ink layer include, for example, gravure printing and flexographic printing. The amount of ink applied when forming the ink layer is, for example, preferably 0.5 g/m ² or more and 15 g/m ² or less, more preferably 1 g/m ² or more and 5 g/m ² or less. The ink layer is preferably formed over the entire laminated film 10 when viewed from the thickness direction of the laminated film 10. That is, it is preferable that the ink layer is also formed on a portion that will be thermally welded when a packaging bag is formed using the laminated film 10, when viewed from the thickness direction of the laminated film 10.

[Adhesive layer 12]
The main component of the adhesive layer 12 is maleic anhydride graft polymerized polypropylene having heat-melting properties. The main component of the adhesive layer 12 is a component having the highest content rate among the components constituting the adhesive layer 12, and is a component having a content rate of 50% by mass or more based on the total mass of the adhesive layer 12. , the denaturation concentration does not matter. Hereinafter, maleic anhydride graft polymerized polypropylene will also be referred to as modified PP. The adhesive layer 12 includes, for example, homopolypropylene, block polypropylene, random polypropylene, and propylene-α-olefin copolymer as components other than the main component. α-olefins are, for example, ethylene and 1-butene.

Modified PP is polypropylene obtained by graft-modifying polypropylene with maleic anhydride. Polypropylene for producing modified PP is, for example, homopolypropylene, block polypropylene, random polypropylene, and propylene-α-olefin copolymer. α-olefins are, for example, ethylene and 1-butene.

The melting point of the modified PP is preferably 100°C or higher. Thereby, the retort resistance of the laminated film 10 can be improved. The grafting ratio of maleic anhydride in the modified PP is 0.1% by mass or more and 1% by mass or less. By having a graft ratio of 0.1% by mass or more, sufficient adhesive strength can be obtained, thereby suppressing delamination after sterilization. When the grafting rate is 1% by mass or less, the resin properties of the modified PP are stabilized. Note that when the grafting rate exceeds 1% by mass, the reaction catalyst used when grafting polypropylene promotes decomposition of the PP resin body, thereby reducing the molecular weight of the modified PP. When the molecular weight of modified PP becomes smaller, the MFR (Melt Flow Rate) of modified PP becomes extremely high, which lowers the film forming suitability, and the film strength decreases, making it difficult to obtain adhesive strength. There may be none. The modified PP is one type selected from those mentioned above, or a combination of two or more types.

The thickness of the adhesive layer 12 is preferably 1 μm or more and 30 μm or less, more preferably 1 μm or more and 15 μm or less. When the thickness of the adhesive layer 12 is 1 μm or more, delamination between the gas barrier film layer 11 and the thermoplastic resin layer 13 is suppressed. When the thickness of the adhesive layer 12 is 30 μm or less, the thermal conductivity of the laminated film 10 is maintained high, so that when a packaging bag is formed using the laminated film 10, it has appropriate lamination strength. You can get the packaging bag.

[Thermoplastic resin layer 13]
The thermoplastic resin layer 13 includes a polypropylene resin and an incompatible component that is incompatible with the polypropylene resin. The thermoplastic resin constituting the thermoplastic resin layer 13 may be any resin that has thermal fusibility. The content of the incompatible component is 1% by mass or more and 40% by mass based on the total amount of the thermoplastic resin layer 13.

Examples of the polypropylene resin include a homopolypropylene resin, a propylene-ethylene random copolymer, a propylene-ethylene block copolymer, and a propylene-α-olefin copolymer. Incompatible components include, for example, low density polyethylene resin, medium density polyethylene resin, linear low density polyethylene resin, polypropylene, ethylene-vinyl acetate copolymer, ethylene-α olefin copolymer, ethylene-methacrylic acid resin. These include ethylene resins such as copolymers, blend resins of polyethylene and polybutene, and metal crosslinked products thereof.

In consideration of suitability for retort sterilization in food packaging, the thermoplastic resin forming the thermoplastic resin layer 13 is preferably polypropylene and heat-resistant LLDPE. The thermoplastic resin layer 13 may contain only two types of thermoplastic resins, or may contain three or more types of thermoplastic resins.

The thickness of the thermoplastic resin layer 13 may be 30 μm or more and 200 μm or less. The thickness of the thermoplastic resin layer 13 can be appropriately set depending on the intended use of the laminated film 10.

[Manufacturing method of laminated film]
First, in the method for manufacturing a laminated film, resin films as the gas barrier film layer 11 and the thermoplastic resin layer 13 are prepared. Next, the gas barrier film layer 11 and the thermoplastic resin layer 13 were laminated using a sandwich lamination method. That is, using a melt extrusion method, a resin for forming the adhesive layer 12 is extruded between the gas barrier film layer 11 and the thermoplastic resin layer 13, and the gas barrier film layer 11, the extruded resin layer, and the heat A laminate was obtained in which the plastic resin layers 13 were laminated in this order. Then, using thermal lamination, the laminate was heated at a temperature equal to or higher than the melting point of the resin for forming the adhesive layer 12. Thereby, the adhesion between the gas barrier film layer 11 and the adhesive layer 12 and the adhesion between the adhesive layer 12 and the thermoplastic resin layer 13 are improved, and the gas barrier film layer 11, the adhesive layer 12, and A laminated film consisting of the thermoplastic resin layer 13 was obtained.

Furthermore, the method for producing the laminated film can be changed to a method other than sandwich lamination. That is, the adhesive layer 12 formed from modified PP is laminated on the barrier layer 11d of the gas barrier film layer 11 using a melt extrusion method, a cast film processing method, or a coating processing method. Next, a thermoplastic resin layer 13 is laminated on the adhesive layer 12 laminated on the gas barrier film layer 11 using a thermal lamination method.

In the manufacturing method using the melt extrusion method, the adhesive layer 12 may be formed as a single layer, or a modified PP layer and another polypropylene layer may be laminated by coextrusion with homopolypropylene, random polypropylene, or block polypropylene. It is also possible to form a body. In the manufacturing method using the cast film method, the adhesive layer 12 is formed together with the thermoplastic resin layer 13.

In the manufacturing method using the coating method, first, a liquid coating agent containing modified PP is applied to the surface of the barrier layer 11d of the gas barrier film layer 11. Next, the adhesive layer 12 is formed by heating the applied coating film to evaporate the solvent. The solvent used in the liquid coating agent is a solvent that can disperse or dissolve the modified PP. The solvent may be, for example, toluene, methyl ethyl ketone, methyl cyclohexane, ethyl acetate, and n-propyl acetate. The liquid adhesive coating method is the coating method exemplified in the formation of the primer layer 11b. Further, the method of drying the applied liquid adhesive is the drying method exemplified in the formation of the primer layer 11b.

In packaging bags that require heat sterilization resistance, such as packaging bags for retort heat sterilization, a dry laminating adhesive such as a two-component urethane curing type is used as the adhesive layer of a conventional laminated film. When dry laminating adhesives are used, it takes a long time of one day or more to cure the adhesives so that they are resistant to heat sterilization. Furthermore, during the production of a laminated film, the film close to the winding core may become tightly wound due to heat during curing, and the film properties may deteriorate due to the load caused by the tightened winding. On the other hand, in forming the adhesive layer 12 described above, since a dry laminating adhesive such as a two-component urethane curing type is not used, curing time for the adhesive is not required, and the time required to manufacture the laminated film is reduced. It is possible to make it shorter. Further, the film wound near the winding core is prevented from being tightly wound due to heat, and the deterioration of the properties of the laminated film due to the tight winding is suppressed.

In addition, organic solvents such as ethyl acetate and toluene used in dry laminating adhesives remain in the laminated film, so dry laminating is used to reduce VOC emissions and improve safety and environmental compatibility. There is still room for improvement in configurations that use adhesives. In this regard, if the adhesive layer 12 described above is formed by extrusion, no organic solvent is used to form the adhesive layer 12, so it is possible to provide a laminated film with excellent safety and environmental compatibility. be.

(Second layer configuration)
The second layer structure of the laminated film will be described with reference to FIG. 2. The second layer structure is a structure in which the primer layer 11b is omitted from the first layer structure, and the difference is mainly in the layer structure of the gas barrier film layer. In the following, differences from the first layer structure will be mainly explained, and structures similar to the first layer structure will be given the same reference numerals and explanations thereof will be omitted.

As FIG. 2 shows, the second layer configuration also includes a gas barrier film layer 21, an adhesive layer 12, and a thermoplastic resin layer 13. The laminated film 20 is stacked so that one part of the thermoplastic resin layer 13 and the other part face each other, or one part of the thermoplastic resin layer 13 and one part of the thermoplastic resin layer 13 of another laminated film 20 are stacked. The thermoplastic resin layers 13 are stacked so as to face each other, and a packaging bag is formed by thermally welding the thermoplastic resin layers 13 together.

The packaging bag is sterilized at a temperature of 80°C or higher and 130°C or lower. The non-thermal welded portion in the packaging bag after sterilization satisfies Conditions 1 and 2 above. In addition, the peel strength of the heat-welded part in the packaging bag after sterilization should be 28N/15mm or more when the peel strength of the heat-welded part is continuously measured from the start point to the end point, and under the above conditions. 3, or the above condition 4 is satisfied.

The gas barrier film layer 21 includes a base film layer 21a, a metal oxide layer 11c, and a barrier layer 11d. The metal oxide layer 11c is located between the base film layer 21a and the barrier layer 11d. The metal oxide layer 11c is in contact with the base film layer 21a and the barrier layer 11d. The metal oxide layer 11c and the barrier layer 11d are located between the base film layer 21a and the adhesive layer 12.

The base film layer 21a includes a plasma-treated surface 21af. The metal oxide layer 11c is in contact with the surface 21af of the base film layer 21a. The barrier layer 11d is in contact with the surface of the metal oxide layer 11c that is opposite to the surface that is in contact with the base film layer 21a.

The base film layer 21a is the same as the base film layer 11a described in the first embodiment, except that it includes a plasma-treated surface 21af. The plasma treatment is, for example, reactive ion etching, and is performed using a hollow anode plasma treatment apparatus equipped with an anode facing the surface 21af. The plasma-treated surface 21af has various adhesion functions such as a chemical adsorption function and an anchor function, thereby increasing the adhesion between the surface 21af and the metal oxide layer 11c.

(Third layer configuration)
The third layer structure of the laminated film will be described with reference to FIG. 3. The third layer structure is a structure in which the primer layer 11b and the metal oxide layer 11c are omitted from the first layer structure, and the layer structure of the gas barrier film layer is different. In the following, differences from the first layer structure will be mainly explained, and structures similar to the first layer structure will be given the same reference numerals and explanations thereof will be omitted.

As shown in FIG. 3, the third layer configuration also includes a gas barrier film layer 31, an adhesive layer 12, and a thermoplastic resin layer 13. The laminated film 30 is stacked so that one part of the thermoplastic resin layer 13 faces the other part, or one part of the thermoplastic resin layer 13 and one part of the thermoplastic resin layer 13 of another laminated film 30 are stacked. The thermoplastic resin layers 13 are stacked so as to face each other, and a packaging bag is formed by thermally welding the thermoplastic resin layers 13 together.

The packaging bag is sterilized at a temperature of 80°C or higher and 130°C or lower. The non-thermal welded portion in the packaging bag after sterilization satisfies Conditions 1 and 2 above. In addition, the peel strength of the heat-welded part in the packaging bag after sterilization should be 28N/15mm or more when the peel strength of the heat-welded part is continuously measured from the start point to the end point, and under the above conditions. 3, or the above condition 4 is satisfied.

[Gas barrier film layer 31]
The gas barrier film layer 31 includes a base film layer 11a and a barrier layer 31d. The barrier layer 31d is located between the base film layer 11a and the adhesive layer 12, and is in contact with the base film layer 11a and the adhesive layer 12.

The material constituting the barrier layer 31d is a dried coating film containing a water-soluble polymer having hydroxyl groups. A water-soluble polymer is a polymer that can be completely dissolved or finely dispersed in water at room temperature.
The material constituting the barrier layer 31d includes, for example, a polycarboxylic acid polymer. A polycarboxylic acid polymer is a polymer having two or more carboxy groups in one molecule. Polycarboxylic acid polymers include, for example, homopolymers of α,β-monoethylenically unsaturated carboxylic acids, copolymers of two or more types of α,β-monoethylenically unsaturated carboxylic acids, α,β- It is a copolymer of monoethylenically unsaturated carboxylic acid and other ethylenically unsaturated monomers. Further, polycarboxylic acid polymers are acidic polysaccharides having carboxyl groups in the molecule, such as alginic acid, carboxymethyl cellulose, and pectin. As the polycarboxylic acid polymer constituting the barrier layer 31d, one type selected from those mentioned above can be used alone, or two or more types can be used in combination.

α,β-Monoethylenically unsaturated carboxylic acids are, for example, acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid and crotonic acid. Other ethylenically unsaturated monomers that can be copolymerized with α,β-monoethylenically unsaturated carboxylic acids include, for example, saturated carboxylic acid vinyl esters, alkyl acrylates, alkyl methacrylates, alkyl itaconates, and acrylonitrile. , vinyl chloride, vinylidene chloride, vinyl fluoride, vinylidene fluoride, and styrene. Saturated carboxylic acid vinyl esters are, for example, ethylene, propylene, and vinyl acetate.

When the polycarboxylic acid polymer is a copolymer of α,β-monoethylenically unsaturated carboxylic acid and other ethylenically unsaturated monomers, the copolymer of α,β-monoethylenically unsaturated carboxylic acid The copolymerization ratio is preferably 60 mol% or more, more preferably 80 mol% or more, and even more preferably 90 mol% or more.

When the polycarboxylic acid-based polymer is a polymer formed only from α,β-monoethylenically unsaturated carboxylic acids, the polymer may include acrylic acid, methacrylic acid, itaconic acid, maleic acid, and fumaric acid. A carboxylic acid-based polymer can be obtained by polymerizing at least one polymerizable monomer selected from the group consisting of , and crotonic acid. The polymer is preferably a polymer obtained by polymerizing at least one polymerizable monomer selected from the group consisting of acrylic acid, methacrylic acid, and maleic acid. Moreover, it is more preferable that the polymer is polyacrylic acid, polymethacrylic acid, polymaleic acid, or a mixture thereof.

When the polycarboxylic acid polymer is an acidic polysaccharide, the monomer component is preferably alginic acid. The number average molecular weight of the polycarboxylic acid polymer is preferably 2,000 or more and 10,000,000 or less, more preferably 5,000 or more and 1,000,000 or less. Thereby, when forming the barrier layer 31d by coating, the processability of the barrier layer 31d can be improved.

The barrier layer 31d may contain other polymers in addition to the polycarboxylic acid polymer as long as gas barrier properties are not impaired. The barrier layer 31d may be formed from a mixture of a polycarboxylic acid polymer and a polyalcohol, for example.

Polyalcohols are compounds containing two or more hydroxyl groups in the molecule, and may be low-molecular compounds or alcohol-based polymers. Polyalcohols may be, for example, polyvinyl alcohol, sugars, starch, and the like. The above-mentioned low molecular weight compounds are, for example, glycerin, ethylene glycol, propylene glycol, 1,3-propanediol, pentaerythritol, polyethylene glycol, and polypropylene glycol. The polyalcohols contained in the barrier layer 31d can be selected from those listed above alone or in combination of two or more.

The degree of saponification of polyvinyl alcohol is preferably 95% or more, more preferably 99% or more. The average degree of polymerization of polyvinyl alcohol is preferably 300 or more and 1,500 or less. The polyalcohol is preferably a vinyl alcohol poly(meth)acrylic acid copolymer containing vinyl alcohol as a main component. A vinyl alcohol poly(meth)acrylic acid copolymer containing vinyl alcohol as a main component is preferable because it is compatible with polycarboxylic acid polymers.

The saccharides may be monosaccharides, oligosaccharides, and polysaccharides. Saccharides include sugar alcohols, sugar alcohol substitutes, and sugar alcohol derivatives. Examples of sugar alcohols include sorbitol, mannitol, dulcitol, xylitol, and erythritol. The sugar is preferably a sugar that dissolves in water, alcohol, or a mixed solution of water and alcohol. As the saccharide contained in the barrier layer 31d, one type selected from the above-mentioned saccharides can be used alone, or two or more types can be used in combination.

Starches are included in polysaccharides. Starches are, for example, raw starch, that is, unmodified starch, or various processed starches. Raw starches are, for example, wheat starch, corn starch, potato starch, tapioca starch, rice starch, sweet potato starch, and sago starch. Examples of modified starch include physically modified starch, enzyme-modified starch, chemically modified starch, and grafted starch obtained by graft polymerizing a monomer to starch. Among starches, preferred are water-soluble processed starch obtained by hydrolyzing potato starch with acid, or sugar alcohols in which aldehyde groups, which are terminal groups of starch, are substituted with hydroxyl groups. Starches may be hydrated. As for the starches contained in the barrier layer 31d, one kind selected from those mentioned above can be used alone, or two or more kinds can be used in combination.

The ratio of the mass (MC) of the polycarboxylic acid polymer to the mass of the polyalcohol (MA) (MC:MA) is preferably from 99:1 to 20:80, and preferably from 95:5 to 40: The ratio is more preferably 60, and even more preferably 95:5 to 50:50. Thereby, it is possible to obtain the barrier layer 31d having excellent barrier properties against oxygen gas even under high humidity conditions.

One method for forming the barrier layer 31d is to first apply a first coating liquid containing a polycarboxylic acid polymer and a solvent, or a second coating liquid containing a polycarboxylic acid polymer, a polyalcohol, and a solvent. A coating liquid is applied onto the base film layer 11a. Next, the first coating liquid or the second coating liquid is dried to evaporate the solvent to form the barrier layer 31d.

The first coating liquid is prepared by dissolving or dispersing the polycarboxylic acid polymer in a solvent. The solvent may be any liquid that can uniformly dissolve or disperse the polycarboxylic acid polymer. The solvent may be, for example, water, methyl alcohol, ethyl alcohol, isopropyl alcohol, dimethyl sulfoxide, dimethyl formamide, dimethyl acetamide, and the like. The solvent is preferably a non-aqueous solvent or a mixture of a non-aqueous solvent and water. The concentration of the polycarboxylic acid polymer in the first coating liquid is preferably 0.1% by mass or more and 50% by mass or less.

The second coating liquid can be prepared by, for example, a method of dissolving each component other than the solvent constituting the second coating liquid in a solvent, a method of mixing a solution containing each component, and a method of dissolving carboxyl groups in a solution of polyalcohols. It is prepared by a method of polymerizing a monomer containing the following and, if necessary, neutralizing the solution using an alkali after the polymerization. The solvent may be, for example, water, alcohol, and a mixture of water and alcohol. The solid content concentration in the second coating liquid is preferably 1% by mass or more and 30% by mass.

The first coating liquid and the second coating liquid may contain other polymers, softeners, plasticizers, stabilizers, etc. as long as the oxygen gas barrier properties of the barrier layer 31d formed using these are not impaired. The composition may also contain an anti-blocking agent, an anti-blocking agent, an adhesive, an inorganic layered compound, and the like. Note that the plasticizer excludes low-molecular compounds having two or more hydroxyl groups in the molecule. The inorganic layer compound is, for example, montmorillonite.

The first coating liquid may contain a compound containing at least one of a monovalent metal and a divalent metal. Thereby, the barrier property of the barrier layer 31d against oxygen gas can be improved. Monovalent metals and divalent metals are, for example, sodium, potassium, zinc, calcium, magnesium, and copper. Examples of compounds containing at least one of a monovalent metal and a divalent metal include sodium hydroxide, zinc oxide, calcium hydroxide, and calcium oxide. The amount of the compound containing at least one of a monovalent metal and a divalent metal added to the first coating liquid is preferably 70 mol% or less based on the carboxyl group of the polycarboxylic acid polymer. , more preferably 50 mol% or less.

For the purpose of improving oxygen gas barrier properties, a second coating liquid may be applied to the base film layer 11a, and heat treatment may be performed after drying the coating film. At this time, in order to ease the heat treatment conditions, a water-soluble alkali metal compound or an alkali metal salt of an inorganic acid or an organic acid is added to the second coating liquid when preparing the second coating liquid. May be added. Alkali metal compounds are, for example, lithium hydroxide, sodium hydroxide, potassium hydroxide. The amount of the alkali metal compound added is preferably 30 mol % or less based on the carboxyl groups of the polycarboxylic acid polymer contained in the second coating liquid. Alkali metal salts of inorganic and organic acids include, for example, lithium chloride, sodium chloride, potassium chloride, sodium bromide, sodium phosphinate (sodium hypophosphite), disodium hydrogen phosphite, disodium phosphate, and ascorbic acid. sodium acid, sodium acetate, sodium benzoate, and sodium hyposulfite. Among these alkali metal salts, phosphinate metal salts such as sodium phosphinate and calcium phosphinate are preferred. The amount of the alkali metal salt added is preferably 0.1 parts by mass or more and 40 parts by mass or less, more preferably 1 part by mass or more and 30 parts by mass or less, based on 100 parts by mass of the solid content of the second coating liquid.

A method that can be used for forming the primer layer 11b is used for the method of forming a coating film using the first coating liquid and the second coating liquid, and the method of drying the coating film. be able to.

Another method for forming the barrier layer 31d is to apply a coating liquid containing a monomer that forms a polycarboxylic acid polymer onto the base film layer 11a. Next, the coating liquid is irradiated with ultraviolet rays or electron beams to polymerize the monomers, thereby forming the barrier layer 31d.

Another method for forming the barrier layer 31d is to deposit a monomer forming a polycarboxylic acid polymer onto the base film layer 11a, and to polymerize the monomer by irradiating the deposited monomer with an electron beam. A barrier layer 31d is formed.

The thickness of the barrier layer 31d is preferably 10 μm or less, more preferably 5 μm or less, and even more preferably 1 μm or less. The barrier layer 31d may include a coating layer containing a zinc compound on the surface that contacts the adhesive layer 12.

Examples of zinc compounds include zinc oxides, hydroxides, carbonates, organic acid salts, and inorganic acid salts. Preferred zinc compounds are zinc oxide, zinc hydroxide, zinc carbonate, zinc acetate, and zinc phosphate. Zinc has low toxicity, and the white zinc sulfide produced by the reaction between hydrogen sulfide and zinc, which causes retort odor, has little effect on the appearance of packaging bags.

From the viewpoint of coating suitability and dispersibility in solvents, the zinc compound is preferably in the form of particles with an average particle size of 5 μm or less, more preferably 1 μm or less, and even more preferably 0.1 μm or less. preferable. The content of the zinc compound is preferably 32.7 mg or more as zinc in 1 m ² of the laminated film 30. If 1 m ² of the laminated film 30 contains 32.7 mg or more of zinc, the effect of hydrogen sulfide being absorbed by the zinc compound is likely to be sensually recognized. The content of the zinc compound is preferably 65.4 mg or more as zinc in 1 m ² of the laminated film 30, even more preferably 131 mg or more, and particularly preferably 196 mg or more. As the content of the zinc compound increases, the effect of absorbing retort odor also increases. Note that as the content of the zinc compound increases, the flavor of the contents may be impaired. For example, when the content is a food whose flavor derived from sulfur-containing compounds is important, such as a garlic seasoning product, the flavor of the food is likely to be impaired. Therefore, it is preferable to change the content of the zinc compound as appropriate depending on the contents of the packaging bag.

The thickness of the coating layer is preferably 0.1 μm or more and 10 μm or less, more preferably 0.1 μm or more and 2 μm or less, and even more preferably 0.1 μm or more and 1 μm or less. When the thickness of the coating layer is 0.1 μm or more, the thickness of the coating layer is likely to be stable. When the thickness of the coating layer is 10 μm or less, the coating layer becomes difficult to cause cohesive failure.

The method for forming the coating layer includes, for example, applying a coating agent containing a solvent or a dispersion medium and a zinc compound. Examples of the solvent or dispersion medium include water, methyl alcohol, ethyl alcohol, isopropyl alcohol, dimethyl sulfoxide, dimethyl formamide, toluene, hexane, acetone, methyl ethyl ketone, diethyl ether, dioxane, tetrahydrofuran, ethyl acetate, and butyl acetate. It is. From the viewpoint of coating suitability and manufacturability, the solvent or dispersion medium is preferably methyl alcohol, ethyl alcohol, isopropyl alcohol, toluene, ethyl acetate, or water. The number of solvents or dispersion media may be one type, or two or more types may be mixed.

In addition, the coating agent may contain additives such as a resin, a surfactant, a softener, a stabilizer, a film-forming agent, an anti-blocking agent, and an adhesive as appropriate. Examples of the resin include paint resins such as alkyd resins, melamine resins, acrylic resins, nitrified cotton, urethane resins, polyester resins, phenol resins, amino resins, fluororesins, and epoxy resins. From the viewpoint of dispersibility of the zinc compound, the coating agent preferably contains a dispersant.

From the viewpoint of coating suitability, the content of the zinc compound is preferably 1% by mass or more and 50% by mass or less based on the coating agent. As a method for forming a coating layer using a coating agent, a method that can be used for forming the primer layer 11b can be used.

(4th layer configuration)
The fourth layer structure of the laminated film will be described with reference to FIG. 4. The fourth layer structure is a structure in which the primer layer 11b and the metal oxide layer 11c are omitted from the first layer structure, and the layer structure of the gas barrier film layer is different. In the following, differences from the first layer structure will be mainly explained, and structures similar to the first layer structure will be given the same reference numerals and explanations thereof will be omitted.

As shown in FIG. 4, the fourth layer configuration also includes a gas barrier film layer 41, an adhesive layer 12, and a thermoplastic resin layer 13. The laminated film 40 is stacked so that one part of the thermoplastic resin layer 13 and the other part face each other, or one part of the thermoplastic resin layer 13 and one part of the thermoplastic resin layer 13 of another laminated film 40 are stacked. The thermoplastic resin layers 13 are stacked so as to face each other, and a packaging bag is formed by thermally welding the thermoplastic resin layers 13 together.

The packaging bag is sterilized at a temperature of 80°C or higher and 130°C or lower. The non-thermal welded portion in the packaging bag after sterilization satisfies Conditions 1 and 2 above. In addition, the peel strength of the heat-welded part in the packaging bag after sterilization should be 28N/15mm or more when the peel strength of the heat-welded part is continuously measured from the start point to the end point, and under the above conditions. 3, or the above condition 4 is satisfied.

The gas barrier film layer 41 includes a base film layer 11a and a barrier layer 41d. The barrier layer 41d contains a hydrolysis product of a metal oxide and a phosphorus compound. The hydrolysis product of the metal oxide and the phosphorus compound increases the adhesion between the base film layer 11a and the barrier layer 41d, thereby causing delamination between the base film layer 11a and the barrier layer 41d. suppress.

The barrier layer 41d is a single layer containing a hydrolysis product of a metal oxide and a phosphorus compound, or a multilayer containing a hydrolysis product.
The metal atoms constituting the metal oxide are, for example, Mg, Ca, Zn, Al, Si, Ti, and Zr, and have a valence of two or more. Metal oxides are produced by hydrolyzing and condensing metal compounds having a hydrolyzable functional group. A method for hydrolyzing and condensing a metal compound is a liquid phase synthesis method such as a sol-gel method. Metal oxides are minute particles, and have, for example, a spherical shape, a flat shape, a polyhedral shape, a fibrous shape, and a needle shape. From the viewpoint of improving barrier properties and hot water resistance, the metal oxide particles are preferably fibrous or acicular. The average particle diameter of the metal oxide particles is, for example, 1 nm or more and 0.5 μm or less. From the viewpoint of excellent barrier properties and transparency of the barrier layer 41d, the average particle diameter of the metal oxide is preferably 1 nm or more and 100 nm or less.

Examples of phosphorus compounds include phosphoric acid, polyphosphoric acid, phosphorous acid, phosphonic acid, and derivatives thereof. The phosphorus compound has one or more reaction points that react with the metal oxide. The reaction point is a bond between a phosphorus atom and an oxygen atom, or a bond between a phosphorus atom and a halogen atom.

A hydrolysis product of a metal oxide and a phosphorus compound has a structure in which metal oxide particles are bonded to each other via phosphorus atoms derived from the phosphorus compound. The hydrolysis product of a metal oxide and a phosphorus compound can be obtained, for example, by heat-treating a coating film containing a metal oxide and a phosphorus compound.

The barrier layer 41d may also contain polysaccharides such as polyvinyl alcohol, partially saponified polyvinyl acetate, polyethylene glycol, polyhydroxyethyl (meth)acrylate, starch, and polysaccharide derivatives derived from polysaccharides. Further, the barrier layer 41d may contain polyacrylic acid, polymethacrylic acid, (poly)acrylic acid/methacrylic acid, and salts thereof. The barrier layer 41d is made of ethylene-vinyl alcohol copolymer, ethylene-maleic anhydride copolymer, styrene-maleic anhydride copolymer, isobutylene-maleic anhydride alternating copolymer, ethylene-acrylic acid copolymer. , a saponified product of ethylene-ethyl acrylate copolymer.

From the viewpoint of obtaining high barrier properties and high hot water resistance, the maximum absorption wave number in the infrared absorption spectrum in the range of 800 cm ^-1 to 1400 cm ^-1 in the barrier layer 41d is in the range of 1080 cm ^-1 to 1130 cm ^-1 . It is preferable that it be within. The metal atom is preferably Al because the maximum absorption wave number is within the range of 1080 cm ^-1 to 1130 cm ^-1 .

From the viewpoint of suppressing dimensional changes in the gas barrier film layer 41 during printing or lamination, the upper limit of the thickness of the barrier layer 41d is preferably 4.0 μm, more preferably 2.0 μm, and 1.0 μm. is more preferable, and 0.9 μm is particularly preferable. Moreover, the thinner the barrier layer 11d is, the higher the flexibility of the gas barrier film layer 41 is, and the mechanical properties of the gas barrier film layer 41 can be brought closer to the mechanical properties of the base film layer 11a itself. Note that the lower limit of the thickness of the barrier layer 41d is preferably 0.1 μm, more preferably 0.2 μm.

(packaging bag)
One embodiment of the packaging bag will be described with reference to FIGS. 5 to 7. Note that the packaging bag is manufactured using a laminated film having any one of the first layer structure to the third layer structure.

The packaging bag is manufactured, for example, by the following three bag manufacturing methods.
As shown in FIG. 5, one example of a method for manufacturing a packaging bag uses, for example, two laminated films 50A each having a rectangular shape. The two laminated films are stacked so that the thermoplastic resin layers 13 located on all sides of the two laminated films 50A are in contact with each other. Then, the thermoplastic resin layers 13 located on the four sides are thermally welded together to produce one packaging bag including the thermally welded portion 50Ah.

As shown in FIG. 6, another example of a method for manufacturing a packaging bag uses, for example, one laminated film 50B having a rectangular shape. One sheet of laminated film 50B is folded in half so that the thermoplastic resin layers 13 in one sheet of laminated film 50B are in contact with each other. The thermoplastic resin layers 13 on three sides of the folded laminated film 50B are then thermally welded together to produce one packaging bag including the thermally welded portion 50Bh.

As shown in FIG. 7, another example of a method for manufacturing a packaging bag uses, for example, a single laminated film having a rectangular shape. The laminated film 50C is bent into a cylindrical shape so that the thermoplastic resin layer 13 in the laminated film 50C is on the inside. Then, the thermoplastic resin layers 13 located at the connection portions of the cylindrical surface are thermally welded to each other to form a back sticking portion, and the thermoplastic resin layers 13 located at the upper and lower openings of the cylindrical surface are thermally welded to each other. As a result, a pillow-shaped packaging bag having a heat-welded portion 50Ch is manufactured.

[Example 1]
The barrier layer 11d of the gas barrier film layer 11 having the first layer structure and the thermoplastic resin layer 13 were laminated using a sandwich lamination method. At this time, the surface of the thermoplastic resin layer 13 was subjected to a corona discharge treatment, and the surface subjected to the corona discharge treatment was made to face the adhesive layer 12. Furthermore, modified PP and random polypropylene were coextruded to a thickness of 20 μm between the gas barrier film layer and the thermoplastic resin layer 13 using a melt extrusion method. Then, a thermal lamination method is performed in which the laminate is heated at a temperature higher than the melting point of the coextruded resin to improve the adhesion between the barrier layer 11d and the adhesive layer 12, and the bond between the adhesive layer 12 and the thermoplastic resin layer 13. Improved adhesion. As a result, a laminated film of Example 1 consisting of the gas barrier film layer 11, the adhesive layer 12, and the thermoplastic resin layer 13 was obtained.

Using the two laminated films of Example 1, stack them so that the thermoplastic resin layers of each laminated film are in contact with each other, heat weld the thermoplastic resin layers 13 located on three sides, and A packaging bag having a length of 100 mm and a longitudinal length of 150 mm was manufactured. Then, 100 g of seasonings including vinegar, oil, salt, and spices are filled from the upper opening of the packaging bag, and the thermoplastic resin layers 13 located at the top of the packaging bag are sealed by heat welding. In this way, the packaging bag of Example 1 was obtained.

Maleic anhydride graft polymerized polypropylene (manufactured by Mitsubishi Chemical Corporation) was used as the modified PP. The melting point peaks of the modified PP are 104°C, 140°C, and 155°C, the density of the modified PP is 0.88 g/cm ³ , and the MFR of the modified PP is 10.3 g/10 min. In addition, using a sample of modified PP, 1H-NMR measurement and 1H-NMR measurement after methyl esterification of the maleic acid site were performed, and the grafting rate was calculated in mass % from the difference in 1H peak area. The graft ratio was 0.1% by mass or more and 1% by mass or less.

Ethylene-propylene-1-butene terpolymer (trade name "FL02C", manufactured by Nippon Polypropylene Co., Ltd.) was used as the random polypropylene. The melting point of random polypropylene is 138° C., the density of block polypropylene is 0.89 g/cm ³ , and the MFR of block polypropylene is 18 g/10 min.

As the thermoplastic resin layer 13, an unstretched polypropylene film (trade name "ZK500", manufactured by Toray Film Processing Co., Ltd.) for retort sterilization with a thickness of 70 μm was used.
The thermal welding temperature during thermal welding is 180° C., the thermal welding time is 1 second, and the thermal welding pressure is 0.2 MPa.

[Example 2]
The gas barrier film layer was changed to a gas barrier film layer 21 having a second layer structure, and the thermoplastic resin layer 13 was replaced with an unstretched polypropylene film for retort sterilization with a thickness of 50 μm (product name "ZK500": Toray Co., Ltd.). A laminated film and a packaging bag of Example 2 were obtained in the same manner as in Example 1 except that the film was changed to (manufactured by Film Processing Co., Ltd.).

[Example 3]
The gas barrier film layer was changed to a gas barrier film layer 21 having a third layer configuration. In addition, the thermoplastic resin layer 13 was changed to a 50 μm thick laminate made of a thermoplastic resin blended with homopolypropylene, random polypropylene, and an elastomer in a weight ratio of 50:20:30, and other than that, In the same manner as in Example 1, a laminated film and a packaging bag of Example 3 were obtained.

[Comparative example 1]
A laminate film and a packaging bag of Comparative Example 1 were obtained in the same manner as in Example 1 except that the thermoplastic resin layer 13 was changed to a 50 μm thick laminate made of homopolypropylene.

[Comparative example 2]
A laminate film and a packaging bag of Comparative Example 2 were obtained in the same manner as in Example 1 except that the thermoplastic resin layer 13 was changed to a 50 μm thick laminate made of random polypropylene.

[evaluation]
The packaging bags of Examples 1 to 3 and the packaging bags of Comparative Examples 1 and 2 were sterilized under the following conditions.

Sterilization temperature: 121℃
Sterilization time: 30 minutes Next, a test piece of the non-thermal welded part was cut out from the packaging bag after sterilization treatment, and a non-instrumented impact test was performed in accordance with JIS K 7211-2:2006 and JIS K 7211-1. :2006, an instrumented impact test was conducted under the following conditions. In addition, in the non-metered impact test, the occurrence of visually confirmed cracks in the test piece was defined as failure. Table 1 shows the energy at maximum impact force and the mode of fracture for Examples 1 to 4 and Comparative Examples 1 and 2.

Striker shape: Hemispherical with a diameter of 20mm Striker mass: 500g
Fixed fall height: 130cm
As shown in Figure 8, a test piece 50P was cut out from the packaging bag after sterilization treatment, and the heat seal strength (peel strength) was measured using a tensile tester under the following conditions in accordance with JIS Z 0238:1998. was measured.

Ten test pieces 50P were taken from the side seals on two sides and the top seal of one packaging bag, with ten measurement sites on each seal. Each test piece 50P has a band shape that is folded back at the heat weld part 50PA, and as shown in FIG. 9, the test piece 50P was developed in a direction perpendicular to the extending direction of the heat weld part 50PA. In this state, the width was 15 mm and the unfolded length was 100 mm or more. Among both ends in the extending direction of the heat welding part 50PA, the end that forms the boundary between the heat welding part 50PA and a part other than the heat welding part 50PA is the starting point 50P1, and the end other than the starting point 50P1 is the ending point 50P2. be.

In the measurement of peel strength, both ends of the test piece 50P are held between clamps, and both ends are pulled at a constant speed so as to widen the distance between the ends of the test piece 50P, and the tensile distance, which is the distance traveled by both ends, is measured. The relationship between the peel strength and the load applied to the test piece 50P was measured. Then, the maximum value Sm among the peel strengths of 30 test pieces 50P collected from one packaging bag, the average peel strength after the maximum value was obtained for the test pieces 50P in gradual decrease mode, and The average value in the stable region was measured for each test piece 50P in the stable mode.

Here, the relationship between tensile distance and peel strength is divided into three types: breaking mode, gradual decrease mode, and stable mode. The fracture mode is observed in test piece 50P, which is evaluated to have sufficiently high peel strength. The gradual decrease mode is observed in the test piece 50P whose peel strength is evaluated to be lower than the fracture mode. The stable mode is observed in the test piece 50P whose peel strength is evaluated to exist between the breaking mode and the gradual decreasing mode.

In the rupture mode, when both ends of the test piece 50P are pulled at a constant speed, the peel strength is sufficiently high that the laminated film cannot withstand the load before the peel strength reaches its maximum value, thereby causing rupture. This phenomenon is observed. The position at which the laminated film breaks is approximately at the starting point 50P1. In the fracture mode, the peel strength cannot be determined, and it can be said that the test piece 50P has sufficient peel strength.

On the other hand, as shown in FIG. 10, in the gradual decrease mode, when both ends of the test piece 50P are pulled at a constant speed, the peel strength reaches the maximum value and peeling occurs from the starting point, and then the peel strength increases until the end point 50P2. A phenomenon in which the amount gradually decreases is observed. In the gradual decrease mode, the average value of peel strength after the maximum value is obtained is calculated, and the average value of peel strength after the maximum value of peel strength is detected ( The ratio of Su) (Su/Sm) was calculated as the peel strength ratio.

In addition, as shown in FIG. 11, in the stable mode, when both ends of the test piece 50P are pulled at a constant speed, the peel strength reaches the maximum value Sm and peeling occurs from the starting point, and then the peel strength reaches the maximum value. After reaching the value Sm, a phenomenon is observed in which the peel strength once stabilizes and then gradually decreases. In the stable mode, the peel strength in the stable region, which is the tensile distance at which the peel strength is stable, is calculated, and the average value (Ss) of the peel strength in the stable region is calculated relative to the maximum peel strength Sm. The ratio (Ss/Sm) was calculated as the peel strength ratio. Note that the stable region of peel strength is a region where the peel strength is maintained within ±5 N/mm after the maximum value of the peel strength is detected.

Table 1 shows the maximum value Sm of peel strength and peel strength ratio for Examples 1 to 3 and Comparative Examples 1 and 2.
Tensile speed: 300mm/min
Peeling angle: 180 degrees In addition, the appearance of the packaging bag after sterilization treatment was visually checked to confirm the presence or absence of delamination. In the appearance evaluation in Table 1, the mark "O" indicates the level at which no delamination occurs in the appearance evaluation.

In addition, with the packaging bag filled with the contents cooled to 5°C, the packaging bag was allowed to fall freely from a height of 100 cm in a horizontal position so that the corners of the packaging bag did not hit the top surface of the concrete. The state of destruction in the packaging bag that fell onto the top surface of the bag was visually confirmed. In the drop bag resistance evaluation in Table 1, the "○" mark indicates the level at which no leakage of contents was observed due to destruction such as tearing of the non-thermal welded part or peeling of the heat-welded part, and the "x" mark indicates Indicates the level at which leakage of contents was observed due to destruction such as tearing of non-thermal welded parts or peeling of heat-welded parts.

As shown in Table 1, in all of Examples 1 to 3, it was observed that the maximum impact energy was 0.45 J or more, and the mode of failure was penetration. That is, it was confirmed that Condition 1 and Condition 2 were satisfied in the non-thermal welded portion of the packaging bag after sterilization. On the other hand, in both Comparative Example 1 and Comparative Example 2, the energy at maximum impact force was less than 0.45 J, and it was recognized that the mode of failure was tearing.

Further, in all of Examples 1 to 3, the maximum peel strength was found to be 28 N/15 mm or more. Further, in all of Examples 1 to 3, the peel strength ratio was found to be 0.3 or more. That is, even after the maximum value of peel strength was observed in the welded part of the packaging bag after sterilization treatment, a peel strength equivalent to 30% of the maximum value was obtained, and under the above condition 3 or condition 4 was found to be satisfied. On the other hand, in both Comparative Example 1 and Comparative Example 2, although the maximum value of peel strength is 28 N/15 mm or more, the peel strength ratio is less than 0.3, and the maximum value of peel strength After this was recognized, it was recognized that almost no peel strength could be obtained.

In both Examples 1 to 3 and Comparative Examples 1 and 2, it was found that no delamination occurred in the evaluation of appearance. On the other hand, in the drop bag resistance evaluation, no leakage of the contents was observed in any of Examples 1 to 3, but in Comparative Examples 1 and 2, tearing of non-thermal welded parts and cracking of heat-welded parts were observed. Leakage of contents was observed due to damage such as peeling.

As described above, according to the embodiment described above, the effects described below can be obtained.
(1) Since the non-thermal welded portion of the laminated film satisfies Conditions 1 and 2, it is possible to improve resistance to dropped bags after sterilization treatment. In particular, the occurrence of delamination can be sufficiently suppressed even in packaging applications containing contents containing volatile substances.

(2) Since the heat-welded portion of the packaging bag satisfies Condition 3 or Condition 4, it is possible to improve resistance to falling bags after sterilization treatment. In particular, the occurrence of delamination can be sufficiently suppressed even in packaging applications containing contents containing volatile substances.

(3) When the grafting rate of modified PP is 0.1% by mass or more, sufficient adhesive strength can be obtained, and delamination after sterilization treatment can be suppressed.
(4) When the grafting rate of the modified PP is 1% by mass or less, it is also possible to stabilize the resin properties of the modified PP.

(5) Since a dry laminating adhesive such as a two-component urethane curing type is not used, curing time for the adhesive is not required, and the time required to manufacture the laminated film can be shortened.

(6) The film wound near the winding core is prevented from being tightly wound due to heat, and the deterioration of the properties of the laminated film due to the tight winding is also suppressed.
(7) If the adhesive layer 12 is formed by extrusion, no organic solvent is used to form the adhesive layer 12, so it is possible to provide a laminated film with excellent safety and environmental compatibility.

10,20,30,40,50A,50B,50C...Laminated film, 11,21,31,41...Gas barrier film layer, 11a, 21a...Base film layer, 11b...Primer layer 11b...Metal oxide layer, 11d, 31d, 41d... Barrier layer, 12... Adhesive layer, 13... Thermoplastic resin layer, 21af... Surface, 50Ah, 50Bh, 50Ch... Heat welding part.

Claims (7)

a gas barrier film layer;
a thermoplastic resin layer;
an adhesive layer located between the gas barrier film layer and the thermoplastic resin layer,
A packaging bag that is sealed by thermal welding of the thermoplastic resin layers that are overlapped so as to face each other to form an edge of the packaging bag , and that includes a non-thermal welded portion surrounded by the edge of the packaging bag. A laminated film for
The main component of the adhesive layer is maleic anhydride graft polymerized polypropylene,
The thermoplastic resin layer includes a polypropylene resin and an incompatible component that is incompatible with the polypropylene resin, and the incompatible component includes an ethylene resin, a blend resin of polyethylene and polybutene, and at least one selected from the group consisting of these metal crosslinked materials, and the content of the incompatible component is 1% by mass or more and 40% by mass based on the total amount of the thermoplastic resin layer;
As the thermal welding, the thermoplastic resins are thermally welded together at a temperature of 180° C. for 1 second at a pressure of 0.2 MPa, and the packaging bag is heated for 30 minutes at a temperature of 80° C. or higher and 130° C. or lower. In the non-thermal welded part of the packaging bag, the following conditions 1 and 2 are satisfied,
The grafting ratio of maleic anhydride in the maleic anhydride graft polymerized polypropylene is 0.1% by mass or more and 1% by mass or less,
The gas barrier film layer is
a base film layer;
a barrier layer located between the base film layer and the adhesive layer;
a primer layer located between the base film layer and the barrier layer;
a metal oxide layer located between the primer layer and the barrier layer,
The materials constituting the barrier layer include a condensate of a metal alkoxide, a condensate of a hydrolysis product of a metal alkoxide, a condensate of an alkoxysilylalkyl isocyanurate, and a coating film of a water-soluble polymer having a hydroxyl group. Contains any one selected from the group consisting of dry matter,
(Condition 1) The maximum impact energy according to JIS K 7211-2:2006 is 0.45J or more,
(Condition 2) The mode of destruction is penetration in accordance with JIS K 7211-1:2006.
Laminated film. a gas barrier film layer;
a thermoplastic resin layer;
an adhesive layer located between the gas barrier film layer and the thermoplastic resin layer,
A packaging bag that is sealed by thermal welding of the thermoplastic resin layers that are overlapped so as to face each other to form an edge of the packaging bag , and that includes a non-thermal welded portion surrounded by the edge of the packaging bag. A laminated film for
The main component of the adhesive layer is maleic anhydride graft polymerized polypropylene,
The thermoplastic resin layer includes a polypropylene resin and an incompatible component that is incompatible with the polypropylene resin, and the incompatible component includes an ethylene resin, a blend resin of polyethylene and polybutene, and at least one selected from the group consisting of these metal crosslinked materials, and the content of the incompatible component is 1% by mass or more and 40% by mass based on the total amount of the thermoplastic resin layer;
As the thermal welding, the thermoplastic resins are thermally welded together at a temperature of 180° C. for 1 second at a pressure of 0.2 MPa, and the packaging bag is heated for 30 minutes at a temperature of 80° C. or higher and 130° C. or lower. In the non-thermal welded part of the packaging bag, the following conditions 1 and 2 are satisfied,
The grafting ratio of maleic anhydride in the maleic anhydride graft polymerized polypropylene is 0.1% by mass or more and 1% by mass or less,
The gas barrier film layer is
a base film layer;
a barrier layer located between the base film layer and the adhesive layer;
a primer layer located between the base film layer and the barrier layer;
a metal oxide layer located between the primer layer and the barrier layer,
The primer layer includes a reaction product of either one of trialkoxysilane and a hydrolysis product of trialkoxysilane, an acrylic polyol, and an isocyanate compound.
(Condition 1) The maximum impact energy according to JIS K 7211-2:2006 is 0.45J or more,
(Condition 2) The mode of destruction is penetration in accordance with JIS K 7211-1:2006.
Laminated film. a gas barrier film layer;
a thermoplastic resin layer;
an adhesive layer located between the gas barrier film layer and the thermoplastic resin layer,
A packaging bag that is sealed by thermal welding of the thermoplastic resin layers that are overlapped so as to face each other to form an edge of the packaging bag , and that includes a non-thermal welded portion surrounded by the edge of the packaging bag. A laminated film for
The main component of the adhesive layer is maleic anhydride graft polymerized polypropylene,
The thermoplastic resin layer includes a polypropylene resin and an incompatible component that is incompatible with the polypropylene resin, and the incompatible component includes an ethylene resin, a blend resin of polyethylene and polybutene, and at least one selected from the group consisting of these metal crosslinked materials, and the content of the incompatible component is 1% by mass or more and 40% by mass based on the total amount of the thermoplastic resin layer;
As the thermal welding, the thermoplastic resins are thermally welded together at a temperature of 180° C. for 1 second at a pressure of 0.2 MPa, and the packaging bag is heated for 30 minutes at a temperature of 80° C. or higher and 130° C. or lower. In the non-thermal welded part of the packaging bag, the following conditions 1 and 2 are satisfied,
The grafting ratio of maleic anhydride in the maleic anhydride graft polymerized polypropylene is 0.1% by mass or more and 1% by mass or less,
The gas barrier film layer is
a base film layer including a plasma treated surface;
a barrier layer;
a metal oxide layer located between the surface of the base film layer and the barrier layer,
(Condition 1) The maximum impact energy according to JIS K 7211-2:2006 is 0.45J or more,
(Condition 2) The mode of destruction is penetration in accordance with JIS K 7211-1:2006.
Laminated film. a gas barrier film layer;
a thermoplastic resin layer;
an adhesive layer located between the gas barrier film layer and the thermoplastic resin layer,
A packaging bag that is sealed by thermal welding of the thermoplastic resin layers that are overlapped so as to face each other to form an edge of the packaging bag , and that includes a non-thermal welded portion surrounded by the edge of the packaging bag. A laminated film for
The main component of the adhesive layer is maleic anhydride graft polymerized polypropylene,
The thermoplastic resin layer includes a polypropylene resin and an incompatible component that is incompatible with the polypropylene resin, and the incompatible component includes an ethylene resin, a blend resin of polyethylene and polybutene, and at least one selected from the group consisting of these metal crosslinked materials, and the content of the incompatible component is 1% by mass or more and 40% by mass based on the total amount of the thermoplastic resin layer;
As the thermal welding, the thermoplastic resins are thermally welded together at a temperature of 180° C. for 1 second at a pressure of 0.2 MPa, and the packaging bag is heated for 30 minutes at a temperature of 80° C. or higher and 130° C. or lower. In the non-thermal welded part of the packaging bag, the following conditions 1 and 2 are satisfied,
The grafting ratio of maleic anhydride in the maleic anhydride graft polymerized polypropylene is 0.1% by mass or more and 1% by mass or less,
The gas barrier film layer is
a base film layer;
a barrier layer located between the base film layer and the adhesive layer, the barrier layer containing a polycarboxylic acid polymer;
(Condition 1) The maximum impact energy according to JIS K 7211-2:2006 is 0.45J or more,
(Condition 2) The mode of destruction is penetration in accordance with JIS K 7211-1:2006.
Laminated film. a gas barrier film layer;
a thermoplastic resin layer;
an adhesive layer located between the gas barrier film layer and the thermoplastic resin layer,
A packaging bag that is sealed by thermal welding of the thermoplastic resin layers that are overlapped so as to face each other to form an edge of the packaging bag , and that includes a non-thermal welded portion surrounded by the edge of the packaging bag. A laminated film for
The main component of the adhesive layer is maleic anhydride graft polymerized polypropylene,
The thermoplastic resin layer includes a polypropylene resin and an incompatible component that is incompatible with the polypropylene resin, and the incompatible component includes an ethylene resin, a blend resin of polyethylene and polybutene, and at least one selected from the group consisting of these metal crosslinked materials, and the content of the incompatible component is 1% by mass or more and 40% by mass based on the total amount of the thermoplastic resin layer;
As the thermal welding, the thermoplastic resins are thermally welded together at a temperature of 180° C. for 1 second at a pressure of 0.2 MPa, and the packaging bag is heated for 30 minutes at a temperature of 80° C. or higher and 130° C. or lower. In the non-thermal welded part of the packaging bag, the following conditions 1 and 2 are satisfied,
The grafting ratio of maleic anhydride in the maleic anhydride graft polymerized polypropylene is 0.1% by mass or more and 1% by mass or less,
The gas barrier film layer is
a base film layer;
a barrier layer located between the base film layer and the adhesive layer, the barrier layer containing a hydrolysis product of a metal oxide and a phosphorus compound;
(Condition 1) The maximum impact energy according to JIS K 7211-2:2006 is 0.45J or more,
(Condition 2) The mode of destruction is penetration in accordance with JIS K 7211-1:2006.
Laminated film. A packaging bag in which thermoplastic resin layers of a laminated film are overlapped so as to face each other and sealed by thermal welding of the thermoplastic resin layers,
A packaging bag, wherein the laminated film is the laminated film according to any one of claims 1 to 5 . In the heat-welded portion of the sterilized packaging bag,
The maximum peel strength of the heat-welded portion that is the edge of the packaging bag is 28 N/15 mm or more, and the following condition 3 or the following condition 4 is satisfied,
(Condition 3) The peel strength has a stable region after the maximum value is obtained, and the ratio of the peel strength to the maximum value in the stable region is 0.3 or more.
(Condition 4) The peel strength does not have the stable range, and the ratio of the average peel strength to the maximum value after the maximum value is obtained is 0.3 or more.
The packaging bag according to claim 6 .