Resin laminate, packaging container, and method for manufacturing resin laminate

Abstract

A resin laminate that has at least a first layer, a second layer, and an intermediate layer that contacts the first layer and the second layer, the surface of the first layer that contacts the intermediate layer being an oxidized surface, the surface of the intermediate layer that contacts the first layer being an oxidized surface, the first layer being formed from a thermoplastic resin or cellophane, and the intermediate layer comprising polyethylene that has a density of no more than 0.915 g / cm3.

Description

[Technical Field]

[0001] The present invention relates to a resin laminate, a packaging container, and a method for producing a resin laminate. This application claims priority based on Japanese Patent Application No. 2020-118202, filed on July 9, 2020, the contents of which are incorporated herein by reference. [Background technology]

[0002] BACKGROUND ART Laminates of two or more types of resins (resin laminates) are used as materials for packaging containers for various liquid products such as liquid seasonings, liquid detergents, and liquid cosmetics.

[0003] Conventionally, the resin laminate has been known to be a laminate having a structure in which two or more types of resin films are bonded together via an adhesive or an anchor coating agent. Resin laminates manufactured using an adhesive or an anchor coating agent can achieve sufficiently high peel strength between the resin films. However, when an adhesive or an anchor coating agent is used, VOCs (volatile organic compounds) are generated during the manufacturing process of the resin laminate.

[0004] In response to this, in recent years, from the viewpoints of preserving the working environment and protecting the environment, techniques for producing resin laminates without emitting VOCs while ensuring peel strength have been studied. For example, a production method is known in which at least one surface of a plastic substrate is oxidized and at least one surface of a melt-extruded film is ozone treated, and the plastic substrate and the melt-extruded film are brought into contact with each other and pressure-bonded (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 7-314629 Summary of the Invention [Problem to be solved by the invention]

[0006] However, the inventors' investigations revealed that the methods described in the above-mentioned patent documents sometimes result in insufficient peel strength of the resulting laminate, and there was a demand for a resin laminate that more reliably ensures peel strength.

[0007] The present invention has been made in view of the above circumstances, and has an object to provide a resin laminate that exhibits sufficient peel strength without using an adhesive or anchor coating agent. It is also an object of the present invention to provide a packaging container made from such a resin laminate. It is also an object of the present invention to provide a method for producing a resin laminate that ensures peel strength and does not generate VOCs. [Means for solving the problem]

[0008] In order to solve the above problems, one aspect of the present invention includes the following aspects.

[0009] [1] A laminated laminate having at least a first layer, a second layer, and an intermediate layer laminated in contact with the first layer and the second layer, wherein the surface of the first layer that contacts the intermediate layer is an oxidized surface, and at least the surface of the intermediate layer that contacts the first layer is an oxidized surface, the first layer is a layer made of a thermoplastic resin or a layer made of cellophane, and the intermediate layer has a density of 0.915 g / cm 3 A resin laminate comprising the following polyethylene:

[0010] [2] The resin laminate according to [1], wherein the thermoplastic resin is at least one selected from the group consisting of polyethylene terephthalate, polyamide, polyethylene naphthalate, polyacrylonitrile, polycarbonate, polyimide, polyethylene, polypropylene, and cyclic polyolefin.

[0011] [3] The resin laminate according to [1] or [2], wherein the second layer is made of at least one material selected from the group consisting of polyethylene, polypropylene, and cyclic polyolefin.

[0012] [4] The resin laminate according to [3], wherein the second layer has a barrier coat layer on the side of the intermediate layer.

[0013] [5] The resin laminate according to [1] or [2], wherein the second layer is a layer made of a barrier material.

[0014] [6] The resin laminate according to any one of [1] to [5], wherein the first layer has a barrier coating layer on the surface.

[0015] [7] The resin laminate according to any one of [1] to [5], wherein the first layer is a layer made of a barrier material.

[0016] [8] The resin laminate according to any one of [1] to [7], which has a printed layer laminated on the first layer.

[0017] [9] The resin laminate according to [8], wherein the printed layer is provided between the first layer and the intermediate layer.

[0018]

[10] A packaging container made from the resin laminate according to any one of [1] to [9], wherein the second layer faces the inside of the container.

[0019]

[11] A method for producing a resin laminate in which a first film and a second film are laminated without an adhesive or an anchor coating agent, the method comprising the steps of: subjecting a surface of the first film to atmospheric pressure plasma treatment in a nitrogen atmosphere or a mixed atmosphere of nitrogen and hydrogen; and sandwiching a molten resin film between the first film and the second film to bond the first film and the second film together; wherein the first film is a thermoplastic resin film or a cellophane film, and the molten resin film has a density of 0.915 g / cm. 3The method for producing a resin laminate is made of the following polyethylene, and the laminating step comprises: facing the surface of the first film that has been subjected to the atmospheric pressure plasma treatment to the second film; and continuously laminating the molten resin film between the first film and the second film by melt-extruding the molten resin film while performing ozone treatment on at least the surface of the molten resin film that comes into contact with the first film.

[0020]

[12] The method for producing a resin laminate according to

[11] , wherein the processing temperature of the molten resin film is 280°C or higher and 350°C or lower.

[0021]

[13] The method for producing a resin laminate according to

[11] or

[12] , wherein the thermoplastic resin film is made of at least one material selected from the group consisting of polyethylene terephthalate, polyamide, polyethylene naphthalate, polyacrylonitrile, polycarbonate, polyimide, polyethylene, polypropylene, and cyclic polyolefin.

[0022]

[14] The method for producing a resin laminate according to any one of

[11] to

[13] , wherein the second film is one selected from the group consisting of unstretched polyethylene resin film, unstretched polypropylene resin film, cyclic polyolefin resin film, and co-extruded film of unstretched polyethylene and unstretched polypropylene.

[0023]

[15] The method for producing a resin laminate according to

[13] , wherein the second film has a barrier coating layer on the surface that comes into contact with the molten resin film.

[0024]

[16] The method for producing a resin laminate according to any one of

[11] to

[14] , wherein the second film is made of a barrier material.

[0025]

[17] The method for producing a resin laminate according to any one of

[11] to

[16] , wherein the first film has a barrier coating layer on the surface.

[0026]

[18] The method for producing a resin laminate according to any one of

[11] to

[16] , wherein the first film is made of a barrier material. [Effects of the Invention]

[0027] According to the present invention, it is possible to provide a resin laminate that exhibits sufficient peel strength without using an adhesive or anchor coating agent. It is also possible to provide a packaging container made from such a resin laminate. It is also possible to provide a method for producing a resin laminate that ensures peel strength and does not generate VOCs. [Brief explanation of the drawings]

[0028] [Figure 1] FIG. 1 is a schematic cross-sectional view showing a resin laminate 1 of the present embodiment. [Figure 2] FIG. 2 is a schematic diagram showing a packaging container 50 formed using the resin laminate 1. As shown in FIG. [Figure 3] FIG. 3 is a process diagram showing a method for producing the resin laminate 1 of this embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0029] Hereinafter, a resin laminate according to an embodiment of the present invention will be described with reference to the drawings. In all of the following drawings, the dimensions and proportions of each component are appropriately changed to make the drawings easier to understand.

[0030] 1 is a schematic cross-sectional view showing a resin laminate 1 of this embodiment. The resin laminate 1 has a first layer 11, a second layer 12, and a first intermediate layer 13. The first intermediate layer corresponds to the "intermediate layer" in the present invention.

[0031] Furthermore, the resin laminate 1 may have a printed layer 14 and a second intermediate layer 15. The combined configuration of the first layer 11, the printed layer 14, and the second intermediate layer 15 may be referred to as the substrate 10.

[0032] (1st layer) The first layer 11 is a layer made of a thermoplastic resin or a layer made of cellophane.

[0033] The thermoplastic resin is preferably at least one selected from the group consisting of polyethylene terephthalate (PET), polyamide (PA), polyethylene naphthalate (PEN), polyacrylonitrile (PAN), polycarbonate (PC), polyimide (PI), polyethylene (PE), polypropylene (PP), and cyclic polyolefins (COP, COC).

[0034] The melting points of these thermoplastic resins are polyethylene terephthalate (252°C), polyamide (220°C), polyethylene naphthalate (approximately 270°C), polyethylene (approximately 130°C), and polypropylene (approximately 160°C), respectively. Of the above-mentioned thermoplastic resins, the melting points of polyacrylonitrile, polycarbonate, polyimide, and cyclic polyolefin cannot be measured (they do not have melting points).

[0035] Polyamide refers to a linear polymer whose main chain is made up of repeated amide bonds (-CONH-) formed by the reaction of acid and amine. A common trade name for polyamide is nylon.

[0036] The first layer 11 may have a barrier coating layer on its surface. In this case, the first layer has a laminated structure of a main layer made of a thermoplastic resin or cellophane and a barrier coating layer provided on the surface. The barrier coating layer may be provided on one surface 11a of the first layer 11 (the surface in contact with the first intermediate layer 13) or on the other surface 11b (the surface in contact with the second intermediate layer 15).

[0037] The barrier coating layer can be formed by applying a barrier coating agent to the surface of the main layer, which exhibits barrier properties when dried and cured.

[0038] Examples of barrier coating agents include reactive coating agents containing a polymer compound containing a reactive functional group and a crosslinkable compound such as a metal compound or polyisocyanate. The reactive coating agent exhibits barrier properties by crosslinking the polymer compound through reaction of the crosslinkable compound with the reactive functional group. Examples of reactive functional groups that can react with the crosslinkable compound include a hydroxyl group, a carboxyl group, and an amino group.

[0039] Examples of polymer compounds that react with the reactive functional group include one or more of polyvinyl alcohol, ethylene-vinyl alcohol copolymer (EVOH), urethane-based polyol compounds, acrylic polyol compounds, epoxy-based polyol compounds, polyacrylic acid, acrylic acid-acrylic acid ester copolymers, polysaccharides, and oxazoline group-containing compounds.

[0040] Metal compounds used as crosslinkable compounds include one or more of metal alkoxides, metal halides, metal chelate compounds, etc. Metal elements contained in the metal compounds include silicon, titanium, zirconium, tin, aluminum, etc. Metal alkoxides include metal methoxides, ethoxides, propoxides, isopropoxides, butoxides, phenoxides, etc. Metal halides include fluorides, chlorides, bromides, iodides, etc. Chelate compounds include metal complexes containing hydroxycarboxylic acids such as lactic acid, aminocarboxylic acids, phosphoric acids, etc. as chelating ligands.

[0041] Examples of polyisocyanates used as crosslinkable compounds include one or more of diisocyanate compounds such as hexamethylene diisocyanate, tolylene diisocyanate, xylylene diisocyanate, and isophorone diisocyanate, and polyisocyanate compounds obtained as derivatives of diisocyanate compounds.

[0042] The barrier coating agent may be a coating agent containing a barrier polymer compound. Examples of the barrier polymer compound include polyvinylidene chloride, polyvinyl alcohol, and ethylene-vinyl alcohol copolymer (EVOH). A barrier coating layer can be formed by applying a coating material obtained by dissolving or dispersing the barrier polymer compound in a solvent, and then volatilizing the solvent.

[0043] The barrier coating agent may contain water or an organic solvent as a solvent, which may be one or more selected from alcohol-based solvents such as methanol, ethanol, and 2-propanol; ketone-based solvents such as acetone and methyl ethyl ketone; glycol ether-based solvents such as 2-methoxyethanol and dimethoxyethane; ester-based solvents such as ethyl acetate; and aromatic solvents such as toluene.

[0044] The barrier coating agent may contain, as additives, inorganic compound particles such as silica and alumina, clay minerals, fillers such as fillers, silane coupling agents, antioxidants, ultraviolet absorbers, light stabilizers, antistatic agents, colorants, crosslinking agents, crosslinking accelerators, curing agents, etc. The barrier coating layer may contain a resin, or may be a barrier coating layer that does not contain a resin.

[0045] The coating device for the barrier coating agent is not particularly limited, and examples thereof include a gravure coater, a knife coater, a reverse coater, a bar coater, a spray coater, a spin coater, a die coater, a slit coater, a roll coater, a dip coater, etc. When two or more types of barrier coat layers are superimposed, a different coating device may be used for each barrier coat layer, or the same or similar types of coating device may be used.

[0046] The first layer 11 may have a metal vapor deposition layer on the other surface 11b. Surface 11b is the surface of the first layer 11 opposite to the surface that contacts the first intermediate layer 13. The metal vapor deposition layer may be, for example, an aluminum vapor deposition layer. The metal vapor deposition layer functions as a barrier coating layer.

[0047] The first layer 11 may have an inorganic vapor deposition layer on the other surface 11b. The inorganic vapor deposition layer may be, for example, a silicon oxide vapor deposition layer. The inorganic vapor deposition layer functions as a barrier coating layer.

[0048] Alternatively, the first layer 11 may be a laminated film of a film having a barrier coating layer and a film having no barrier coating layer.

[0049] The first layer 11 may be formed from a material having high barrier properties (hereinafter referred to as a barrier material). In this case, the first layer 11 may have a multi-layer structure including a layer of the barrier material.

[0050] Barrier materials include ethylene-vinyl alcohol copolymer (EVOH), polyvinylidene chloride (PVDC), polyvinyl alcohol (PVOH), and polyvinyl chloride (PVC).

[0051] The thickness of the first layer 11 is preferably 5 μm or more and 100 μm or less.

[0052] One surface 11a of the first layer 11 has been subjected to an oxidation treatment, typically a plasma treatment. Surface 11a is the surface of the first layer 11 that comes into contact with the first intermediate layer 13. The fact that surface 11a has been oxidized can be confirmed by sum frequency generation spectroscopy. In other words, surface 11a has been oxidized to a degree that can be confirmed by sum frequency generation spectroscopy. When surface 11a is modified in a nitrogen atmosphere, nitrogen molecules (N2) in the atmosphere react with the thermoplastic resin exposed on surface 11a, forming new C-N bonds.

[0053] Examples of the oxidation treatment method include known corona treatment, plasma treatment, flame plasma treatment, electron beam irradiation, and ultraviolet irradiation.

[0054] The atmosphere for the oxidation treatment may be the nitrogen atmosphere as described above, or a mixed atmosphere of nitrogen and hydrogen.

[0055] (2nd layer) The second layer 12 functions as a sealant layer and is made of at least one material selected from the group consisting of polyolefins and biodegradable resins.

[0056] Examples of polyolefins include polyethylene, polypropylene, and cyclic polyolefins.

[0057] Biodegradable resins include polylactic acid (PLA), polybutylene succinate (PBS), polybutylene succinate adipate (PBSA), polybutylene adipate terephthalate (PBAT), and poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) copolymer resin (PHBH).

[0058] The thickness of the second layer 12 is preferably 10 μm or more and 500 μm or less.

[0059] The second layer 12 may have a barrier coating layer on the surface in contact with the first intermediate layer 13. In this case, the second layer has a laminated structure of a main layer made of at least one material selected from the group consisting of polyolefins and biodegradable resins, and a barrier coating layer provided on the first intermediate layer 13 side of the main layer.

[0060] The barrier coating layer can be formed by applying a barrier coating agent to the surface of the main layer. The barrier coating agent exhibits barrier properties when dried and hardened. The same barrier coating agents as those exemplified for the first layer 11 can be used as the barrier coating agent.

[0061] The second layer 12 may have a metal vapor deposition layer as a barrier coating layer, such as an aluminum vapor deposition layer.

[0062] The second layer 12 may have an inorganic vapor deposition layer as a barrier coating layer, such as a silicon oxide vapor deposition layer.

[0063] The second layer 12 may be formed from a material having high barrier properties (hereinafter referred to as a barrier material). In this case, the second layer 12 may have a multi-layer structure including a layer of the barrier material.

[0064] As the barrier material, the same materials as those exemplified for the first layer 11 can be used.

[0065] (First middle class) The first intermediate layer 13 is in contact with the first layer 11 and the second layer 12 and is laminated with the first layer 11 and the second layer 12 .

[0066] In the resin laminate 1 of this embodiment, a first layer 11 and a second layer 12 are laminated together with a first intermediate layer 13 sandwiched therebetween. The inventors investigated a resin laminate that exhibits sufficient peel strength between the first layer 11 and the second layer without using an adhesive or an anchor coating agent, and found that the density of the resin used in the intermediate layer (first intermediate layer 13) affects the peel strength, leading to the completion of the present invention.

[0067] That is, the first intermediate layer 13 has a density of 0.915 g / cm 3 The density of the polyethylene used to form the first intermediate layer 13 is 0.910 g / cm 3 It is preferable that the following is true:

[0068] The polyethylene used to form the first intermediate layer 13 may be composed of only one type of polyethylene, or may be a mixture of two or more types of polyethylene. In other words, when the polyethylene used to form the first intermediate layer 13 is a mixture of two or more types of polyethylene, the density of the entire composition is 0.915 g / cm. 3 The following is the result.

[0069] The density of the polyethylene used as the material for the first intermediate layer 13 is 0.850 g / cm 3 or more, 0.880 g / cm 3 It is preferable that this is equal to or greater than this.

[0070] The upper and lower limits of the density of the low-density polyethylene can be combined in any desired manner.

[0071] The thickness of the first intermediate layer 13 is preferably 3 μm or more and 500 μm or less.

[0072] The surface 13a of the first intermediate layer 13 facing the first layer 11 has been subjected to an oxidation treatment, typically an ozone treatment. When the second layer 12 has a barrier coat, it is preferable that the surface of the first intermediate layer 13 facing the second layer 12 has been subjected to an oxidation treatment.

[0073] The resin laminate 1 has the first intermediate layer 13 made of polyethylene having the density described above, and the opposing surfaces of the first layer 11 and the first intermediate layer 13 are each oxidized, so that the resin laminate 1 exhibits sufficient peel strength at the interface between the first layer 11 and the first intermediate layer 13.

[0074] In this embodiment, the peel strength can be measured in accordance with the measurement method specified in JIS K 6854-1 "Adhesive peel strength test method, Part 1: 90-degree peel."

[0075] (Printing layer) The print layer 14 is a layer on which characters and designs are printed with printing ink on a surface 14a of a film made of a thermoplastic resin. In FIG. 1, the printed layer 14 is formed on the opposite side of the second intermediate layer 15 from the first layer 11, but it may be formed between the first layer 11 and the first intermediate layer 13.

[0076] The printing ink used to print the letters and designs on the printing layer 14 may contain various ink binder resins such as thermoplastic resin, urethane resin, acrylic resin, etc. Furthermore, the printing ink contains additives such as various pigments, drying agents, stabilizers, etc.

[0077] In the printing layer 14, the letters and patterns are formed by a known printing method such as offset printing, gravure printing, or screen printing. The thickness of the portion constituting the letters and patterns can usually be about 0.05 μm or more and 2.0 μm or less.

[0078] The thickness of the printed layer 14 is preferably 5 μm or more and 100 μm or less.

[0079] The surface 14a of the printed layer 14 may be subjected to an oxidation treatment, typically a plasma treatment, similar to the one surface 11a of the first layer 11. The oxidation treatment can be performed using the known methods described above.

[0080] (Second middle class) The second intermediate layer 15 is in contact with the surface 11b of the first layer 11 and the surface 14a of the printed layer 14, and is laminated with the first layer 11 and the printed layer 14.

[0081] The second intermediate layer 15 can be formed from the same materials as those exemplified as the materials for forming the first intermediate layer 13. The materials for forming the second intermediate layer 15 and the first intermediate layer 13 may be the same.

[0082] The thickness of the second intermediate layer 15 is preferably 10 μm or more and 500 μm or less.

[0083] The surface 15a of the second intermediate layer 15 facing the printed layer 14 has been subjected to an oxidation treatment, typically an ozone treatment. If the first layer 11 has a barrier coating layer on the other surface 11b, the surface 15b of the second intermediate layer 15 facing the first layer 11 has also been subjected to an oxidation treatment, typically an ozone treatment.

[0084] (packaging container) 2 is a schematic diagram showing a packaging container 50 formed using the above-described resin laminate 1. In the packaging container 50, the second layer 12 of the resin laminate 1 faces the inside of the container, and the printed layer 14 is exposed to the outside of the container.

[0085] The packaging container 50 is obtained by overlapping two resin laminates 1 cut to a predetermined size with their second layers 12 facing each other and heat-sealing three sides. In Fig. 2, the heat-sealed portion is indicated by the symbol A.

[0086] The packaging container 50 may also be a self-standing pouch manufactured by a known method.

[0087] (Method of manufacturing resin laminate) 3 is a process diagram showing a method for producing the resin laminate 1 of this embodiment. The resin laminate 1 described above is produced by laminating a first film and a second film without using an adhesive or anchor coating agent.

[0088] In the following description, examples will be shown in which atmospheric pressure plasma treatment and ozone treatment are used as oxidation treatments.

[0089] The base film 10F is a laminate of a first film 11F formed in a strip shape and having the same configuration as the first layer 11, a printed layer 14F formed in a strip shape and having the same configuration as the printed layer 14, and a second intermediate layer 15F formed in a strip shape and having the same configuration as the second intermediate layer 15. When the base film 10F is cut into sheets, it becomes the above-mentioned base material 10.

[0090] First film 11F may have a barrier coating layer on its surface. In this case, first film 11F has a laminated structure of a main layer made of thermoplastic resin or cellophane and a barrier coating layer provided on the surface of the main layer.

[0091] The first film 11F may be made of the above-mentioned barrier material.

[0092] The base film 10F is sequentially unwound from a winding roll 10L wound into a roll, and is carried into the plasma processing device 110 via a transport roll 101.

[0093] The plasma processing apparatus 110 includes a chamber 111, a roll 112, a plasma generator 113, and transport rolls 114 and 115. The chamber 111 houses the roll 112, the plasma generator 113, and the transport rolls 114 and 115.

[0094] The substrate film 10F carried into the plasma processing apparatus 110 is wound around a roll 112 via a transport roll 114. In the chamber 111, an atmosphere suitable for generating plasma is formed.

[0095] The plasma generator 113 is disposed opposite the roll 112 and generates plasma in the space between the plasma generator 113 and the roll 112. The generated plasma oxidizes one surface of the base film 10F (one surface 11a of the first film 11F).

[0096] For example, plasma treatment is performed at an output of 60 W·min / m 2 The process can be carried out under atmospheric pressure conditions, with a conveying speed of 50 m / min and an atmospheric gas of a mixture of nitrogen and hydrogen.

[0097] The substrate film 10F, one surface 11a of which has been subjected to the oxidation treatment, is carried out of the plasma treatment device 110 via the transport rolls 115.

[0098] The oxidation treatment of the one surface 11a of the base film 10F may be carried out continuously during the transport process as described above, or may be carried out in advance.

[0099] The substrate film 10F is fed between cooling nip rolls 103 and 104 via a transport roll 102.

[0100] Further, a second film 12F wound in a roll is disposed near the cooling nip rolls 103 and 104. The second film 12F has the same configuration as the second layer 12 and is formed in a strip shape.

[0101] The second film 12F is preferably one selected from the group consisting of unstretched polyethylene resin film, unstretched polypropylene resin film, cyclic polyolefin resin film, co-extruded film of unstretched polyethylene and unstretched polypropylene, and biodegradable resin film.

[0102] The second film 12F may have a barrier coating layer on the surface that contacts the surface 13a of the molten resin film 13F (described later). In this case, the second film 12F has a laminated structure of a main layer made of at least one material selected from the group consisting of polyolefins and biodegradable resins, and a barrier coating layer provided on the main layer facing the molten resin film 13F.

[0103] The second film 12F may be made of the above-mentioned barrier material.

[0104] The second film 12F is continuously unwound from the unwinding roll 12L and fed between the cooling nip rolls 103 and 104.

[0105] Between the cooling nip rolls 103 and 104, and between the base film 10F and the second film 12F, a film-shaped molten resin film 13F is continuously extruded from an extruder 130 via a T-die.

[0106] The processing temperature of the molten resin film 13F by the extruder 130 is preferably 280° C. or higher, more preferably 290° C. or higher, and even more preferably 300° C. or higher. The processing temperature of the molten resin film 13F is preferably 350° C. or lower, more preferably 340° C. or lower, and even more preferably 320° C. or lower.

[0107] The upper and lower limits of the processing temperature can be combined in any manner, i.e., the processing temperature of the molten resin film may be 280°C or higher and 350°C or lower, 290°C or higher and 340°C or lower, or 300°C or higher and 320°C or lower.

[0108] An ozone treatment device 140 is disposed at a position facing the surface 13a of the molten resin film 13F. The ozone treatment device 140 continuously oxidizes the surface 13a of the molten resin film 13F with ozone.

[0109] In FIG. 3, only the surface 13a is oxidized using the ozone treatment device 140, but the present invention is not limited to this.

[0110] When second film 12F has a barrier coating layer or when second film 12F is made of a barrier material, ozone treatment device 140 may be provided at positions facing both sides of molten resin film 13F, respectively, to oxidize both sides of molten resin film 13F. Furthermore, if both sides of molten resin film 13F can be oxidized, ozone treatment device 140 may be an apparatus configured to oxidize both sides with a single device, rather than being provided at positions facing both sides of molten resin film 13F.

[0111] In this way, the base film 10F, second film 12F, and molten resin film 13F supplied between the cooling nip rolls 103 and 104 are continuously bonded together by passing between the cooling nip rolls 103 and 104 without applying any adhesive or anchor coating agent to the interfaces between them. In this way, the raw sheet 1F of the resin laminate 1 described above is obtained.

[0112] The raw web 1F is transported to the winding roll 1L via transport rolls 105 and 106 and wound up into a roll.

[0113] The raw web 1F is appropriately cut into sheets to form the above-mentioned resin laminate 1. The raw web 1F may also be cut downstream in the process without being wound into a roll.

[0114] In this embodiment, the resin laminate 1 is obtained in the manner described above.

[0115] According to the resin laminate 1 having the above-mentioned configuration, it is possible to provide a resin laminate that exhibits sufficient peel strength without using an adhesive or an anchor coating agent.

[0116] Furthermore, according to the packaging container having the above-mentioned configuration, by using the above-mentioned resin laminate as a material, the packaging container exhibits sufficient peel strength and suppresses VOC emissions.

[0117] Furthermore, according to the method for producing a resin laminate as described above, it is possible to produce a resin laminate without generating VOCs while ensuring peel strength.

[0118] As one aspect, the present invention also includes the following embodiment.

[0119] <1-1> A laminated laminate having at least a first layer, a second layer, and an intermediate layer laminated in contact with the first layer and the second layer, wherein the surface of the first layer that contacts the intermediate layer is an oxidized surface, and the surface of the intermediate layer that contacts the first layer is an oxidized surface, the first layer is a layer made of a thermoplastic resin or a layer made of cellophane, and the intermediate layer has a density of 0.850 g / cm 3 More than 0.915g / cm 3 A resin laminate comprising the following polyethylene:

[0120] <1-2> A laminated laminate having at least a first layer, a second layer, and an intermediate layer laminated in contact with the first layer and the second layer, wherein the surface of the first layer that contacts the intermediate layer is an oxidized surface, and the surface of the intermediate layer that contacts the first layer is an oxidized surface, the first layer is a layer made of a thermoplastic resin or a layer made of cellophane, and the intermediate layer has a density of 0.880 g / cm 3 More than 0.910g / cm 3 A resin laminate comprising the following polyethylene:

[0121] <2-1> A method for producing a resin laminate in which a first film and a second film are laminated together without the use of an adhesive or an anchor coating agent, the method comprising the steps of: subjecting a surface of the first film to atmospheric pressure plasma treatment in a nitrogen atmosphere or a mixed atmosphere of nitrogen and hydrogen; and sandwiching a molten resin film between the first film and the second film to bond the first film and the second film together, wherein the first film is a thermoplastic resin film or a cellophane film, and the molten resin film has a density of 0.850 g / cm. 3 More than 0.915g / cm 3 The method for producing a resin laminate is made of the following polyethylene, and the laminating step comprises: facing the surface of the first film that has been subjected to the atmospheric pressure plasma treatment to the second film; and melt-extruding the molten resin film between the first film and the second film while performing ozone treatment on the surface of the molten resin film that comes into contact with the first film, thereby continuously laminating the film.

[0122] <2-2> A method for producing a resin laminate in which a first film and a second film are laminated without an adhesive or an anchor coating agent, the method comprising the steps of: performing atmospheric pressure plasma treatment on a surface of the first film in a nitrogen atmosphere or a mixed atmosphere of nitrogen and hydrogen; and sandwiching a molten resin film between the first film and the second film to bond the first film and the second film together; wherein the first film is a thermoplastic resin film or a cellophane film, and the molten resin film has a density of 0.880 g / cm. 3 More than 0.910g / cm 3 The method for producing a resin laminate is made of the following polyethylene, and the laminating step comprises: facing the surface of the first film that has been subjected to the atmospheric pressure plasma treatment to the second film; and melt-extruding the molten resin film between the first film and the second film while performing ozone treatment on the surface of the molten resin film that comes into contact with the first film, thereby continuously laminating the film.

[0123] <2-3> The method for producing a resin laminate according to <2-1> or <2-2>, wherein the processing temperature of the molten resin film is 290°C or higher and 340°C or lower.

[0124] <2-4> The method for producing a resin laminate according to <2-3>, wherein the processing temperature of the molten resin film is 300°C or higher and 320°C or lower.

[0125] While the preferred embodiments of the present invention have been described above with reference to the accompanying drawings, the present invention is not limited to these examples. The shapes and combinations of the components shown in the above examples are merely examples, and various modifications can be made based on design requirements, etc., without departing from the spirit of the present invention. [Example]

[0126] The present invention will be described below with reference to examples, but the present invention is not limited to these examples.

[0127] (Examples 1 to 9, Comparative Example 1) A laminate was prepared as the base film, in which a printed layer, a second intermediate layer, and a first layer were laminated in this order. The base film was a strip-shaped molded body, as described in the manufacturing method of the resin laminate described above. Each component is shown below. (Configuration of base film) Printing layer: Layer made of PET. Thickness: 12 μm. Second intermediate layer: low density polyethylene layer, 20 μm thick. First film: A laminated film (VM-PET, manufactured by Toray Advanced Film Co., Ltd.) in which aluminum was vapor-deposited onto a film layer made of PET. Thickness: 12 μm. The aluminum vapor-deposited layer was laminated facing the second intermediate layer.

[0128] While the base film was being transported in the longitudinal direction, the surface of the first layer of the base film (the surface facing the film layer made of PET) was continuously subjected to atmospheric pressure plasma treatment under the following conditions. (Processing conditions) Output: 60W·min / m 2 Atmospheric gas: A mixture of nitrogen and hydrogen. The concentration of hydrogen in nitrogen is 500 ppm. Conveying speed: 50m / min

[0129] The atmospheric pressure plasma-treated surface of the base film was placed opposite a strip-shaped second film, and a film-shaped molten resin (molten resin film) was extruded between the base film and the second film to form an extrusion laminate. The second film used was a 90 μm-thick molded product made of linear low-density polyethylene (LLDPE).

[0130] During the extrusion lamination, the surface of the molten resin film facing the substrate film was subjected to ozone treatment.

[0131] The molten resin film became the first intermediate layer described above. In the obtained resin laminate, the first intermediate layer had a thickness of 20 μm.

[0132] The thickness of the first intermediate layer was calculated by measuring the thickness (total thickness) of the resin laminate using a film thickness meter (constant pressure thickness measuring device) and subtracting the known thicknesses (standard values ​​for purchased films) of the base film and the second film from the total thickness.

[0133] After the extrusion lamination, the resulting laminate was cut into sheets to obtain a resin laminate.

[0134] (Examples 10 and 11) A laminate in which a printed layer and a first layer were laminated in this order was prepared as the base film. The base film was a strip-shaped molded body, as described in the manufacturing method of the resin laminate above. Each component is shown below. (Configuration of base film) First film: High density polyethylene film, 25 μm thick. Printed layer: Ink layer printed directly onto the first film using the gravure method

[0135] While the base film was being transported in the longitudinal direction, the surface of the base film on the side of the printed layer was continuously subjected to atmospheric pressure plasma treatment under the following conditions. (Processing conditions) Output: 80W·min / m 2 Atmospheric gas: Nitrogen Conveying speed: 50m / min

[0136] The atmospheric pressure plasma-treated surface of the base film was placed opposite a strip-shaped second film, and a film-shaped molten resin (molten resin film) was extruded between the base film and the second film to form an extrusion laminate. The second film used was a molded product made of LLDPE and 90 μm thick.

[0137] During the extrusion lamination, the surface of the molten resin film facing the substrate film was subjected to ozone treatment.

[0138] The molten resin film became the first intermediate layer described above. In the obtained resin laminate, the first intermediate layer had a thickness of 20 μm.

[0139] After the extrusion lamination, the resulting laminate was cut into sheets to obtain a resin laminate.

[0140] Example 12 The second film was a laminate consisting of a 90 μm thick LLDPE film and a PVOH coating layer on one side. The coating layer was a thin film below the measurement limit.

[0141] A resin laminate was obtained in the same manner as in Example 10, except that in extrusion lamination, the coating layer of the second film was placed on the molten resin side and both sides of the molten resin film were subjected to ozone treatment.

[0142] The resins used in extrusion lamination in Examples 1 to 9 and Comparative Example 1, i.e., the resins constituting the first intermediate layer, are shown in Table 1. The melt flow rate (MFR) and density of each resin are the manufacturer's nominal values. The significant figures of each value are adjusted to the manufacturer's nominal value.

[0143] [Table 1]

[0144] The obtained resin laminates were evaluated as follows: For each of Examples 1 to 9 and Comparative Example 1, resin laminates were produced under processing conditions in which the processing temperatures of the molten resin during extrusion lamination were 300°C and 320°C, and evaluations were performed.

[0145] (peel strength) The peel strength of the interface between the first intermediate layer and the substrate was measured in accordance with the measurement method specified in JIS K 6854-1 "Adhesives - Peel adhesion strength test method, Part 1: 90 degree peel."

[0146] The evaluation results are shown in Tables 2 and 3. The temperatures listed in the "Peel Strength" columns in Tables 2 and 3 refer to the processing temperatures of the molten resin. In the tables, "-" indicates that data was not available.

[0147] [Table 2]

[0148] [Table 3]

[0149] When the first intermediate layer was a composition of two types of resin, the density of the resin constituting the first intermediate layer was determined by dividing the density of each of the two types of resin proportionally based on the volume ratio of the resins used.

[0150] As a result of the evaluation, it was found that the resin laminates of Examples 1 to 12 had peel strengths of 5 N / inch or more, which were sufficiently high peel strengths.

[0151] In contrast, the density of the resin that makes up the first intermediate layer is 0.915 g / cm 3 It was found that the resin laminate of Comparative Example 1, which exceeded this value, had a peel strength that was weak and did not reach 5 N / inch.

[0152] The above tendency was also observed when the processing temperature was changed from 300°C to 320°C.

[0153] Furthermore, in Examples 3 to 5 and 9, the resin constituting the first intermediate layer had a density of 0.915 g / cm 3 Although the resin contained in the first intermediate layer exceeds 0.915 g / cm, the density of the entire resin composition constituting the first intermediate layer is 0.915 g / cm 3 The peel strength was also high in the resin laminates of Examples 3 to 5 and 9. Therefore, when the material of the first intermediate layer is a composition in which a plurality of resins is mixed, it is considered that the density of the entire composition is 0.915 g / cm 3 It was found that the following was sufficient.

[0154] From the above results, it was found that the present invention is useful. [Industrial Applicability]

[0155] According to the present invention, the film exhibits sufficient peel strength and is therefore suitable for use in stand-up pouches, particularly stand-up pouches for liquids. [Explanation of symbols]

[0156] 1...resin laminate, 11...first layer, 11a, 11b, 13a, 15a...surfaces, 11F...first film, 12...second layer, 12F...second film, 13F...molten resin film, 14, 14F...printed layer, 50...packaging container

Claims

1. At least a first layer; A second layer; an intermediate layer laminated in contact with the first layer and the second layer, a surface of the first layer that is in contact with the intermediate layer is an oxidation-treated surface; At least a surface of the intermediate layer that is in contact with the first layer is an oxidation-treated surface, the first layer is a layer made of a thermoplastic resin or a layer made of cellophane, The intermediate layer has a density of 0.915 g / cm ３ It consists of the following polyethylene: The second layer is a resin laminate made of linear low-density polyethylene.

2. At least a first layer, A second layer; an intermediate layer laminated in contact with the first layer and the second layer, a surface of the first layer that is in contact with the intermediate layer is an oxidation-treated surface; At least a surface of the intermediate layer that is in contact with the first layer is an oxidation-treated surface, the first layer is a layer made of a thermoplastic resin or a layer made of cellophane, the intermediate layer is made of polyethylene having a density of 0.915 g / cm 3 or less; The second layer is a resin laminate that functions as a sealant layer.

3. 3. The resin laminate according to claim 1, wherein the thermoplastic resin is at least one selected from the group consisting of polyethylene terephthalate, polyamide, polyethylene naphthalate, polyacrylonitrile, polycarbonate, polyimide, polyethylene, polypropylene, and cyclic polyolefin.

4. The resin laminate according to claim 1 , wherein the second layer has a barrier coat layer on the side of the intermediate layer.

5. The resin laminate according to claim 1 , wherein the second layer is a layer made of a barrier material.

6. The first layer comprises a main layer made of a thermoplastic resin or cellophane; The resin laminate according to claim 1 , further comprising a barrier coat layer provided on a surface of the main layer.

7. The resin laminate according to claim 1 , wherein the first layer is a layer made of a barrier material.

8. The resin laminate according to claim 1 , further comprising a printed layer laminated on the first layer.

9. The resin laminate according to claim 8 , wherein the printed layer is provided between the first layer and the intermediate layer.

10. A packaging container made from the resin laminate according to any one of claims 1 to 9, A packaging container in which the second layer faces the inside of the container.

11. A method for producing a resin laminate in which a first film and a second film are laminated together without using an adhesive or an anchor coating agent, a step of subjecting a surface of the first film to atmospheric pressure plasma treatment in a nitrogen atmosphere or a mixed atmosphere of nitrogen and hydrogen; a step of sandwiching a molten resin film between the first film and the second film to bond the first film and the second film together, the first film is a thermoplastic resin film or a cellophane film, The molten resin film has a density of 0.915 g / cm ３ It consists of the following polyethylene: the second film is a film made of linear low-density polyethylene, The bonding step is a method for manufacturing a resin laminate, in which the surface of the first film that has been subjected to the atmospheric pressure plasma treatment faces the second film, and the molten resin film is melt-extruded between the first film and the second film to continuously bond them together while performing ozone treatment on at least the surface of the molten resin film that comes into contact with the first film.

12. The method for producing a resin laminate according to claim 11, wherein the processing temperature of the molten resin film is 280°C or higher and 350°C or lower.

13. The method for producing a resin laminate according to claim 11 or 12, wherein the thermoplastic resin film is made of at least one material selected from the group consisting of polyethylene terephthalate, polyamide, polyethylene naphthalate, polyacrylonitrile, polycarbonate, polyimide, polyethylene, polypropylene, and cyclic polyolefin.

14. The method for producing a resin laminate according to claim 11 , wherein the second film has a barrier coating layer on a surface that comes into contact with the molten resin film.

15. The method for producing a resin laminate according to claim 11 , wherein the second film is made of a barrier material.

16. The first film includes a main layer made of a thermoplastic resin or cellophane; The method for producing a resin laminate according to any one of claims 11 to 15, further comprising: a barrier coat layer provided on a surface of the main layer.

17. The method for producing a resin laminate according to claim 11 , wherein the first film is made of a barrier material.

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