Packaging material and method for producing the same

Abstract

To provide a packaging material which is excellent in laminate strength, has easy tearability, and is excellent in recyclability.SOLUTION: A packaging material has a base material, a printed layer, an adhesive layer, and a sealant, and contains 80 mass% or more of a polyolefin resin in the total mass of the packaging material, wherein the printed layer contains a pigment and a binder resin, the adhesive layer is formed of a cured product of a reactive adhesive containing a polyol compound (D) and an isocyanate compound (I), and the molecular weight distribution (Mw / Mn) of the polyol compound (D) is 1.5 to 10.0.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a packaging material and a method for manufacturing the same.

Background Art

[0002] In recent years, there has been an increasing demand for recycling of packaging materials from the viewpoints of environmental protection and effective utilization of resources, in addition to the functions as conventional packaging materials such as laminate strength and tearability. For example, since it is difficult to separate and classify a packaging material having a multilayer structure including a plurality of different materials, a single-material packaging material suitable for material recycling has been studied (Patent Document 1).

[0003] Generally, a pattern such as a design may be attached to a packaging material, and a printing layer made of ink is provided to make the contents invisible. On the printing layer, an adhesive layer, a thermoplastic base material, and the like are further laminated in order to form a laminate for a packaging material. The laminate is heat-sealed between the outermost thermoplastic base materials to form a packaging bag. Such a packaging bag is widely used in the food packaging field. If the adhesion strength between the layers is low, peeling between the layers occurs during filling and transportation of the contents, causing problems such as a decrease in design and leakage of the contents. Therefore, good adhesion strength is required for laminates in the food packaging field.

[0004] In addition, in the case of a packaging bag for food packaging, the packaging bag is often directly torn open by hand to take out the contents. At this time, if the tearability of the packaging bag is poor, problems such as excessive force being applied or the contents being spilled due to tearing in an unexpected direction may occur. Therefore, good tearability is required.

[0005] For example, Patent Document 2 describes a technique for expressing easy tearability by increasing the laminate strength by using an isocyanate-based curing agent in an ink containing a polyurethane resin. Further, Patent Document 3 describes a technique of using a silane coupling agent in addition to the isocyanate-based curing agent. However, both are related to packaging materials composed of different base materials, and problems remain in terms of recyclability. From the above, a technique that achieves both recyclability and physical properties suitable for packaging materials such as laminate strength and easy tearability has not been disclosed so far.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0007] The problem to be solved by the present invention is to provide a packaging material having excellent laminate strength, easy tearability, and excellent recyclability.

Means for Solving the Problems

[0008] As a result of intensive studies, the inventors have found that the above problems can be solved by using the packaging material of the present invention, and have completed the present invention.

[0009] That is, the present invention is a packaging material having a base material, a printing layer, an adhesive layer, and a sealant, containing 80% by mass or more of a polyolefin resin in the total mass of the packaging material, wherein the printing layer contains a pigment and a binder resin, The adhesive layer is composed of a cured product of a reactive adhesive containing a polyol compound (D) and an isocyanate compound (I), and the molecular weight distribution (Mw / Mn) of the polyol compound (D) is 1.5 to 10.0, relating to a packaging material.

[0010] The present invention also relates to the above packaging material, wherein the polyol compound (D) contains structural units derived from a polyether polyol, and the molecular weight distribution (Mw / Mn) of the polyol compound (D) is 3.0 to 10.0.

[0011] The present invention also relates to the above packaging material, wherein the polyol compound (D) contains structural units derived from a polyester polyol, and the molecular weight distribution (Mw / Mn) of the polyol compound (D) is 1.5 to 5.0.

[0012] The present invention also relates to the above packaging material, wherein the chlorine content of the binder resin is 5% by mass or less.

[0013] The present invention also relates to the above packaging material, wherein the binder resin contains a polyester-based urethane resin (B), and the molecular weight distribution (Mw / Mn) of the polyester-based urethane resin (B) is 2.0 to 8.0.

[0014] The present invention also relates to the above packaging material, wherein the polyester-based urethane resin (B) contains structural units derived from a polyester which is a condensate of a dibasic acid and a diol, and the dibasic acid includes sebacic acid and / or succinic acid.

[0015] The present invention also relates to the above packaging material, wherein the diol includes a branched diol and a linear diol.

[0016] The present invention also relates to the above packaging material, wherein the binder resin contains a urethane resin and at least one resin selected from the group consisting of a polyvinyl acetal resin, a cellulose-based resin, a rosin-based resin, and an acrylic resin.

[0017] The present invention also relates to the above packaging material, wherein the content of the pigment is 30% by mass or less in the total mass of the printing layer.

[0018] The present invention also relates to the above packaging material, wherein the printing layer further contains an isocyanate curing agent having a weight average molecular weight of 800 to 8000.

[0019] The present invention also relates to the above packaging material, wherein the base material and the sealant contain a polyolefin resin.

[0020] The present invention also relates to the above packaging material, wherein the polyolefin resin is a polypropylene-based resin.

[0021] The present invention also relates to the above packaging material, wherein the chlorine content is 0.4% by mass or less in the total mass of the packaging material.

[0022] The present invention also relates to a method for manufacturing a packaging material having a base material, a printing layer, an adhesive layer, and a sealant, and containing 80% by mass or more of an olefin resin in the total mass, a step of printing a gravure ink containing a polyester-based urethane resin (B) on the base material to form a printing layer, and a step of applying a reactive adhesive containing a polyol compound (D) and an isocyanate compound (I) to form an adhesive layer, The present invention relates to a method for manufacturing a packaging material, wherein the molecular weight distribution (Mw / Mn) of the polyol compound (D) is 1.5 to 10.0.

Advantages of the Invention

[0023] According to the present invention, it is possible to provide a packaging material having excellent laminate strength, easy tearability, and excellent recyclability.

Embodiments for Carrying Out the Invention

[0024] Hereinafter, embodiments of the present invention will be described in detail. However, the description of the constituent elements described below is an example (representative example) of an embodiment of the present invention, and the present invention is not limited to these contents unless it exceeds the gist thereof.

[0025] In the present invention, "gravure ink" is an embodiment of ink. Further, an ink composed of a mixture of "gravure ink" and an "isocyanate curing agent" is also "gravure ink". The ink constituting the printing layer may be "gravure ink" or any other arbitrary ink form. The printed printing layer may sometimes be simply referred to as an "ink layer", which is synonymous.

[0026] In the following description, the polyester-based urethane resin (B) used for the binder resin of the printing layer refers to a urethane resin containing structural units derived from polyester. Preferably, it is an embodiment of a urethane resin further having a urea bond. On the other hand, the polyester polyol, polyether polyol, and other polyols used for the reactive adhesive are in a form having hydroxyl groups at a plurality of terminals. The polyol compound (D) preferably has a urethane bond, and preferably does not have a urea bond. Note that even a very small amount of urea bond unintentionally formed due to the mixing of moisture or the like during the production of the polyol compound (D) is not excluded.

[0027] Hereinafter, the packaging material of the present invention will be described in detail. The present invention is a packaging material having a base material, a printing layer, an adhesive layer, and a sealant, containing 80% by mass or more of a polyolefin resin in the total mass of the packaging material, wherein the printing layer contains a pigment and a binder resin, the adhesive layer is composed of a reactive adhesive containing a polyol compound (D) and an isocyanate compound (I), and the molecular weight distribution (Mw / Mn) of the polyol compound (D) is 1.5 to 10.0. By containing 80% by mass or more of a polyolefin resin in the total mass of the packaging material, recyclability is exhibited, and a molding material having good moldability after recycling and usable for various applications can be obtained. Further, by using an adhesive containing a polyol compound (D) having a molecular weight distribution (Mw / Mn) of 1.5 to 10.0, the leveling property during adhesive coating and the adhesion between layers become good, and easy tearability can be imparted to the packaging material. Easy tearability contributes to the improvement of recyclability not only in terms of the convenience of simplifying the opening of the packaging material but also in terms of shortening and streamlining the process of crushing and pulverizing the packaging material during material recycling.

[0028] <Packaging material> The packaging material of the present invention is a packaging material having a structure in which at least a base material, a printing layer, an adhesive layer, and a sealant are laminated. Specifically, the structure can be exemplified by the following structures, but is not limited thereto. In the structure representations of the following (1) to (3), " / " means the boundary of each layer. Specifically, the laminated structure can be exemplified by the following laminated structures in order from the outer layer side (left side). (1) Base material / Printing layer / Adhesive layer / Sealant (2) Base material / Printing layer / Adhesive layer / Intermediate base material / Adhesive layer / Sealant (3) Base material / Printing layer / Adhesive layer / First intermediate base material / Adhesive layer / Second intermediate base material / Adhesive layer / Sealant

[0029] The packaging material contains 80% by mass or more of a polyolefin resin in the total mass of the packaging material. The content is more preferably 85% or more, and still more preferably 90% by mass or more. When the packaging material contains a polyolefin resin within the above range, the simplicity of the separation process and the recyclability are high, and a molding material having good moldability and usable for various applications can be obtained. Also, from the viewpoints of recyclability and easy tearability, it is preferable that the base material, the sealant, and the intermediate base material used as required are made of the same material. Further, it is preferable that the base material, the sealant, and the intermediate base material used as required contain a polyolefin resin. Furthermore, in the total mass of the base material, the sealant, and the intermediate base material used as required, it is preferable that the polyolefin resin accounts for 50% by mass or more, more preferably 60% by mass or more, still more preferably 70% by mass or more, further preferably 80% by mass or more, and particularly preferably 90% by mass or more. Moreover, it is more preferable that the polyolefin resin is a polypropylene-based resin and / or a polyethylene-based resin, still more preferably the polyolefin resin is a polypropylene-based resin, and particularly preferably the polypropylene-based resin is a copolymer with ethylene and / or butene.

[0030] <Chlorine content of the packaging material> Due to the halogen elements that may be contained in the packaging material, hydrogen chloride, which is a halogen gas or an acidic gas, may be generated during pellet production, which may damage the equipment or pose a threat to human health. Moreover, when bubbles are generated during pellet production, when using the produced pellets to manufacture molded products, unevenness is likely to occur on the surface, and the surface state of the molded products may deteriorate. Therefore, in the packaging material, the chlorine content is preferably 0.4% by mass or less, more preferably 0.2% by mass or less, still more preferably 0.1% by mass or less, and particularly preferably 0.05% by mass or less in the total mass of the packaging material.

[0031] (Method for measuring the chlorine content of the packaging material) The chlorine content of the above-mentioned packaging material can be measured using known methods such as ion chromatography (IC) or an ICP mass spectrometer (ICP-MS). Specifically, it can be specified by the same method as the analysis method for chlorine content described later.

[0032] <Base material> The substrate preferably has a film or sheet form for use as a packaging material. Further, the substrate preferably contains a polyolefin resin. Furthermore, in the total mass of the substrate, the polyolefin resin is preferably 50% by mass or more, more preferably 60% by mass or more, still more preferably 70% by mass or more, further preferably 80% by mass or more, and particularly preferably 90% by mass or more. Moreover, it is more preferable that the polyolefin resin is a polypropylene-based resin and / or a polyethylene-based resin, still more preferable that the polyolefin resin is a polypropylene-based resin, and particularly preferable that the polypropylene-based resin is a copolymer with ethylene and / or butene.

[0033] As the substrate containing a polyolefin resin, substrates made of only polyolefin resin may be simply laminated, or substrates different from the substrate made of polyolefin resin may be laminated via adhesion or the like. The "substrate different from the substrate made of polyolefin resin" includes films having properties different from those of the substrate made of polyolefin resin, regardless of the type. Also, in the case of a laminated substrate, it may be in a form including an adhesive layer. The method for laminating the above substrates is not particularly limited, and examples include conventionally known methods such as coextrusion manufacturing method, heat fusion, and pressure bonding via an adhesive layer.

[0034] The above-mentioned substrate made of polyolefin resin has higher resistance to alkaline aqueous solutions and heat during the molding process compared to ester-based substrates, and is less likely to undergo thermal decomposition or hydrolysis, etc. Therefore, during recycling, the molecular weight can be maintained at a high level. Furthermore, from the perspective of ease of recovery after recycling, examples of such polyolefin substrates include polyethylene such as biaxially oriented polypropylene (OPP), unoriented polypropylene (CPP), low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), medium-density polyethylene (MDPE), high-density polyethylene (HDPE), etc., acid-modified polyethylene, acid-modified polypropylene, copolymerized polypropylene, and films laminated with these, etc. The thickness of the substrate is not particularly limited, and considering the processability into packaging containers, it is preferably 5 μm or more and 150 μm or less, more preferably 10 μm or more and 70 μm or less. Among them, films having heat-sealability are preferably used, and CPP, heat-sealable OPP, etc. correspond to this.

[0035] The substrate is preferably in the form of a gas barrier substrate, for example, a plastic substrate having an inorganic vapor deposition layer such as aluminum, silica, alumina, etc.; a plastic substrate having an organic layer such as ethylene-vinyl alcohol copolymer, polyvinyl alcohol, etc.

[0036] The substrate is preferably in a form containing (coating or kneading) additives such as antistatic agents, antifogging agents, ultraviolet absorbers, etc., or having an easy-adhesion coating layer (for example, a layer containing polyvinyl alcohol and its derivatives), or a form in which the surface of the substrate is subjected to corona treatment or low-temperature plasma treatment. The above-mentioned addition and processing are also carried out for the purpose of improving the wettability of printing inks and other coating agents, or for the purpose of imparting specific functionality to the film, and are also preferably used, for example, to provide a packaging material with excellent visibility of the contents by preventing the packaging material from fogging due to moisture.

[0037] <Printing layer> The printing layer in the packaging material is a layer that displays any pattern, design, characters, symbols, etc. for the purpose of imparting decoration or aesthetic sense, indicating the contents, expiration date, and the manufacturer or seller, etc., and is not particularly limited. The printing layer may be a solid printing layer. The method for forming the printing layer is not particularly limited and is formed using printing ink containing a pigment and a binder resin. Further, the printing layer may have a single-layer structure or a multi-layer structure and may be formed on the surface layer. The thickness of the printing layer is preferably 0.1 to 8 μm, more preferably 0.5 to 4 μm, and particularly preferably 0.8 to 2.5 μm.

[0038] (Pigment) The printing layer in the packaging material preferably contains a pigment and is formed using printing ink containing a pigment. Considering the quality deterioration due to coloring after recycling, the content of the colorant containing the pigment is preferably 30% by mass or less, still more preferably 25% by mass or less, and even more preferably 23% by mass or less in the total mass of the printing layer. The pigment can be any of organic pigments, inorganic pigments, and extender pigments. As the inorganic pigment, those containing titanium oxide are preferred, and as the extender pigment, silica, barium sulfate, kaolin, clay, calcium carbonate, magnesium carbonate, etc. are preferred. As the organic pigment, those composed of organic compounds and organometallic complexes are preferably used. Colorants such as pigments may be used alone or in combination of two or more. Any of the C.I. Pigment Numbers can be used for the pigment.

[0039] [Organic pigment] Examples of the organic pigment include, but are not limited to, the following pigments: soluble azo-based, insoluble azo-based, azo-based, phthalocyanine-based, halogenated phthalocyanine-based, anthraquinone-based, ansanthrone-based, dianthraquinonyl-based, anthrapyrimidine-based, perylene-based, perinone-based, quinacridone-based, thioindigo-based, dioxazine-based, isoindolinone-based, quinophthalone-based, azomethine azo-based, flavanthrone-based, diketopyrrolopyrrole-based, isoindoline-based, indanthrone-based, carbon black-based pigments, etc. Further, for example, carmine 6B, lake red C, permanent red 2B, disazo yellow, pyrazolone orange, carmine FB, chromophthal yellow, chromophthal red, phthalocyanine blue, phthalocyanine green, dioxazine violet, quinacridone magenta, quinacridone red, indanthrone blue, pyrimidine yellow, thioindigo Bordeaux, thioindigo magenta, perylene red, perinone orange, isoindolinone yellow, aniline black, diketopyrrolopyrrole red, daylight fluorescent pigments can be mentioned.

[0040] As the hue of the organic pigment, at least one selected from the group consisting of black pigment, blue pigment, green pigment, red pigment, purple pigment, yellow pigment, orange pigment, and brown pigment is preferable. Further, at least one selected from the group consisting of black pigment, blue pigment, red pigment, and yellow pigment is preferable. Specific examples of the organic pigment are indicated by the C.I. number of the Color Index International (abbreviation C.I.). Preferably, they are C.I. Pigment Red 57:1, C.I. Pigment Red 48:1, C.I. Pigment Red 48:2, C.I. Pigment Red 48:3, C.I. Pigment Red 146, C.I. Pigment Red 242, C.I. Pigment Yellow 83, C.I. Pigment Yellow 14, C.I. Pigment Orange 38, C.I. Pigment Orange 13, C.I. Pigment Yellow 180, C.I. Pigment Yellow 139, C.I. Pigment Red 185, C.I. Pigment Red 122, C.I. Pigment Red 178, C.I. Pigment Red 149, C.I. Pigment Red 144, C.I. Pigment Red 166, C.I. Pigment Violet 23, C.I. Pigment Violet 37, C.I. Pigment Blue 15, C.I. Pigment Blue 15:1, C.I. Pigment Blue 15:2, C.I. Pigment Blue 15:3, C.I. Pigment Blue 15:4, C.I. Pigment Blue 15:6, C.I. Pigment Green 7, C.I. Pigment Orange 34, C.I. Pigment Orange 64, C.I. Pigment Black 7.

[0041] [Inorganic Pigment] Examples of the inorganic pigment include titanium oxide, zinc oxide, zinc sulfide, barium sulfate, calcium carbonate, chromium oxide, silica, aluminum particles, mica, bronze powder, chrome vermilion, lead yellow, cadmium yellow, cadmium red, ultramarine, dark blue, red iron oxide, iron black, titanium oxide, zinc oxide, etc. Aluminum has a leafing type or a non - leafing type, and the non - leafing type is preferred.

[0042] (Binder Resin) The binder resin refers to the binding resin in the printing layer of the packaging material. As described later, the chlorine content is preferably 5% by mass or less, more preferably 3% by mass or less, and still more preferably 1% by mass or less in the total binder resin.

[0043] Further, the binder resin is preferably a thermoplastic resin soluble in an organic solvent. It is preferable to use in combination a resin having a glass transition temperature of -60°C or higher and lower than 40°C and a resin having a glass transition temperature of 40°C or higher and 200°C or lower. More preferably, a resin having a glass transition temperature of -50°C or higher and 0°C or lower and a resin having a glass transition temperature of 50°C or higher and 190°C or lower are used in combination. In the present specification, the glass transition temperature is a measured value in a differential scanning calorimeter (DSC). The above resin mainly includes urethane resins. Examples of the above resin include polyvinyl acetal resins, cellulose ester resins, rosin resins, etc., and polyvinyl acetal resins are preferred.

[0044] Examples of the binder resin include, but are not limited to, polyether-based urethane resins, polyester-based urethane resins, cellulose-based resins, polyamide resins, rosin-based resins, ethylene-vinyl acetate copolymer resins, vinyl chloride-vinyl acetate copolymer resins, vinyl acetate resins, acrylic resins, styrene resins, dammar resins, styrene-maleic acid copolymer resins, polyester resins, alkyd resins, terpene resins, phenol-modified terpene resins, ketone resins, cyclized rubbers, polyvinyl acetal resins, petroleum resins, and modified resins thereof. These resins can be used alone or in combination of two or more. Among the above, it is preferable that the binder resin does not substantially contain a vinyl chloride-vinyl acetate copolymer resin, more preferably contains a urethane resin, and even more preferably contains a polyester-based urethane resin (B).

[0045] [Polyester-based urethane resin (B)] The polyester-based urethane resin (B) used in the present invention refers to a urethane resin having a structural unit derived from polyester. Preferably, it is in a form having a urea bond. It is preferable that the polyester-based urethane resin (B) has 40% by mass or more, more preferably 50% by mass or more, still more preferably 60% by mass or more, and particularly preferably 65% by mass or more of the structural units derived from polyester in the total mass. The polyester-based urethane resin (B) is not limited to the following, and examples thereof include a polyester-based urethane resin obtained by reacting a polyisocyanate with a polyol containing a polyester polyol to obtain a urethane prepolymer, and further reacting the prepolymer with a polyamine (chain extender) and, if necessary, a reaction terminator. In order to obtain a urethane resin having a structural unit derived from polyester, for example, in the above-described method for synthesizing a urethane resin, a method of using a polyester polyol as the polyol can be used, but it is not particularly limited.

[0046] ≪Polyester Polyol≫ The number average molecular weight of the above polyester polyol is preferably 500 to 10,000, and more preferably 1,000 to 5,000. Here, the above number average molecular weight is calculated from the hydroxyl value, and the hydroxyl value is the amount of hydroxyl groups in 1 g of the resin calculated by esterifying or acetylating the hydroxyl groups in the resin and back-titrating the remaining acid with an alkali, converted to the number of milligrams of potassium hydroxide, and measured according to JIS K0070. When the number average molecular weight of the polyester polyol is 10,000 or less, the anti-blocking property of the printed layer with respect to the plastic film is excellent. Further, when the number average molecular weight of the polyester polyol is 500 or more, the flexibility of the printed layer is improved, and the adhesion to the plastic film is excellent.

[0047] The above polyester polyol is preferably a polyester diol, and the polyester diol is preferably a polyester diol which is a condensate of a diol and a dicarboxylic acid (also referred to as a dibasic acid). The polyester polyol can be used alone or in combination of two or more.

[0048] Examples of the dicarboxylic acid include adipic acid, phthalic anhydride, isophthalic acid, terephthalic acid, maleic acid, fumaric acid, succinic acid, oxalic acid, malonic acid, pimelic acid, azelaic acid, sebacic acid, suberic acid, glutaric acid, 1,4-cyclohexyl dicarboxylic acid, dimer acid, hydrogenated dimer acid, etc. Among them, adipic acid, succinic acid, sebacic acid, etc. are preferable. Further, a polyol having three or more hydroxyl groups and a polyvalent carboxylic acid having three or more carboxyl groups can be used in combination as raw materials for the polyester polyol.

[0049] Examples of the diol include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,3-butanediol, 1,6-hexanediol, 1,8-octanediol, 1,9-nonanediol, neopentyl glycol, 3-methyl-1,5-pentanediol, 2-methyl-1,3-propanediol, 3,3,5-trimethylpentanediol, 2,4-diethyl-1,5-pentanediol, 1,12-octadecanediol, 1,2-alkanediol, 1,3-alkanediol, 1-monoglyceride, 2-monoglyceride, 1-monoglycerol ether, 2-monoglycerol ether, dimer diol, hydrogenated dimer diol, etc. Among them, it is preferably a polyester diol which is a condensate of a diol containing a branched diol and a dicarboxylic acid. Further, it may be a polyester diol obtained by subjecting a cyclic ester (such as lactone) to a ring-opening reaction.

[0050] The above diol can be classified into a linear diol and a branched diol. Here, the linear diol is a diol having two or more atoms, and refers to alkylene glycol, dialkylene glycol, trialkylene glycol and other diols. The branched diol refers to a diol in which at least one hydrogen atom of the hydrocarbon group of alkylene glycol is substituted with an atom other than a hydrogen atom.

[0051] Since linear diols impart crystallinity and branched diols impart flexibility, depending on the balance between them, the polyurethane resin as a binder resin can make the ink film tough and impart high laminate strength and easy tearability to the ink film. It is considered that the inclusion of a branched diol structure and / or a linear diol structure in the polyurethane resin is also effective in the efficiency of recycling the packaging material. As will be described later, it is more preferable that the polyurethane resin contains both a branched diol structure and a linear diol structure.

[0052] Examples of the branched diol include 2-butyl-2-ethyl-1,3-propanediol (hereinafter also referred to as BEPG), 2-methyl-1,3-propanediol (hereinafter also referred to as MPO), 3-methyl-1,5-pentanediol (also referred to as MPD), neopentyl glycol (also referred to as NPG), 1,2-propylene glycol (hereinafter also referred to as PG), 2,4-diethyl-1,5-pentanediol, 1,3-butanediol, dipropylene glycol, etc. At least one branched diol selected from NPG and PG is particularly preferable.

[0053] The linear diol is preferably an alkylene glycol, and examples thereof include ethylene glycol (also referred to as EG), diethylene glycol, 1,3-propanediol (also referred to as 1,3PD), 1,4-butanediol (also referred to as 1,4BD), 1,5-pentanediol, 1,6-hexanediol, 1,8-octanediol, 1,9-nonanediol, 1,4-butynediol, 1,4-butylene glycol, diethylene glycol, triethylene glycol, etc. Among them, linear diols having 8 or less carbon atoms, preferably 6 or less carbon atoms are preferable, and EG, 1,3PD, 1,4BD, 1,5-pentanediol, 1,6-hexanediol, 1,8-octanediol, etc. are preferable. Further, from the viewpoint of physical properties, 1,3PD is particularly preferable.

[0054] When the polyester polyol contains a branched diol and a linear diol, from the viewpoint of the laminate strength, the mass ratio of the branched diol and the linear diol in all the diols of the polyester polyol (branched diol: linear diol) is preferably from 10:90 to 90:10, more preferably from 20:80 to 80:20, and still more preferably from 30:70 to 70:30.

[0055] In addition, the branched diol unit and the linear diol unit may each be present in one polyester polyol, or a polyester polyol containing only the branched diol unit and a polyester polyol containing only the linear diol unit may be used as a mixture raw material to obtain a biomass urethane resin. Approximately the same effect can be obtained.

[0056] Among these, as a preferred specific example of the polyester polyol, those containing both a branched diol and a linear diol together with adipic acid, succinic acid, sebacic acid and other dibasic acids are preferred. Thereby, the laminate strength in the packaging material becomes better.

[0057] ≪Other polyols≫ The above polyol may contain polyols other than the polyester polyol. For example, polyether polyols, polycarbonate polyols, and polyolefin polyols can be used.

[0058] ≪Polyisocyanate≫ As the above polyisocyanate, diisocyanate is preferable, and various known aromatic, aliphatic or alicyclic diisocyanates can be used. For example, 1,5-naphthylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 4,4'-diphenyldimethylmethane diisocyanate, 4,4'-dibenzyl isocyanate, dialkyldiphenylmethane diisocyanate, tetraalkyldiphenylmethane diisocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, tolylene diisocyanate, butane-1,4-diisocyanate, hexamethylene diisocyanate, isopropylene diisocyanate, methylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, cyclohexane-1,4-diisocyanate, xylylene diisocyanate, isophorone diisocyanate, lysine diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, 1,3-bis(isocyanatomethyl)cyclohexane, methylcyclohexane diisocyanate, m-tetramethylxylylene diisocyanate, and dimer diisocyanate obtained by converting the carboxyl group of dimer acid into an isocyanate group are representative examples. These can be used alone or in admixture of two or more. Among them, isophorone diisocyanate, tolylene diisocyanate, and 4,4'-diphenylmethane diisocyanate are preferable, and isophorone diisocyanate is more preferable from the viewpoint of solubility.

[0059] <<Chain extender>> The above chain extender is preferably a polyamine. As the polyamine, an organic diamine is preferred, and examples include, but are not limited to, ethylenediamine, propylenediamine, hexamethylenediamine, isophoronediamine, dicyclohexylmethane-4,4'-diamine, etc. In addition, amines having a hydroxyl group in the molecule, such as 2-hydroxyethylethylenediamine, 2-hydroxyethylpropyldiamine, 2-hydroxyethylpropylenediamine, di-2-hydroxyethylethylenediamine, di-2-hydroxyethylenediamine, di-2-hydroxyethylpropylenediamine, 2-hydroxypyrropylethylenediamine, di-2-hydroxypyrropylethylenediamine, etc., can also be used. These organic diamines can be used alone or in combination of two or more, and isophoronediamine is preferred. Furthermore, polyfunctional amines having 3 or more amino groups, such as diethylenetriamine, iminobispropylamine: (IBPA, 3,3'-diaminodipropylamine), N-(3-aminopropyl)butane-1,4-diamine: (spermidine), 6,6-iminodihexylamine, 3,7-diazanonane-1,9-diamine, N,N'-bis(3-aminopropyl)ethylenediamine, etc., can also be used in combination with the above organic diamines.

[0060] ≪Reaction terminator≫ In the case of a urethane resin that can be produced only in the urethanization step, it is preferable to use a monoalcohol or a monoamine. In the case of a urethane resin produced by performing a ureidation reaction step in addition to the urethanization step, it is preferable to use a monoamine. As the monoalcohol, a substituted or unsubstituted alcohol is preferred, and methanol, ethanol, n-propanol, isopropyl alcohol, 1-butanol, etc. are preferably mentioned. As the monoamine, a substituted or unsubstituted monoamine is preferred, and n-butylamine, n-dibutylamine, octylamine, diethylamine, monoethanolamine, monopropanolamine, diethanolamine, dipropanolamine, etc. are preferably mentioned. Further, as the reaction terminator, the compounds mentioned as the chain extender can also be used, and at least one kind can be used, and two or more kinds can be used in combination.

[0061] In the production of the urethane prepolymer having an isocyanate group at the terminal obtained by reacting the above polyisocyanate and polyol, the molar equivalent ratio of NCO of the polyisocyanate to OH of the polyol (molar equivalent of NCO of the polyisocyanate / molar equivalent of OH of the polyol compound) is preferably reacted at 1.3 to 3, and more preferably reacted at 1.5 to 2.

[0062] The polyester-based urethane resin (B) and other urethane resins preferably have an active hydrogen group such as a hydroxyl group and / or an amino group. When the above resin has a hydroxyl group, the hydroxyl value is preferably 0.5 to 30 mgKOH / g, more preferably 1 to 20 mgKOH / g, and still more preferably 2 to 15 mgKOH / g. When the above resin has an amino group, the amine value is preferably 0.1 to 15 mgKOH / g, and still preferably 1 to 12 mgKOH / g. On the other hand, the acid value of the urethane resin is preferably 5 mgKOH / g or less, and still preferably 3 mgKOH / g or less. This is because the acid value does not contribute to the reaction with the isocyanate-based curing agent described later.

[0063] The weight average molecular weight of the polyester-based urethane resin (B) and other urethane resins is preferably from 20,000 to 100,000, more preferably from 25,000 to 90,000, and even more preferably from 30,000 to 80,000. This is to form a strong film for the printed layer by crosslinking with the isocyanate-based curing agent described later and impart easy tearability. In the present invention, the weight average molecular weight and the molecular weight distribution (Mw / Mn) described later can be measured by gel permeation chromatography (GPC). As an example, as the GPC apparatus, Water2690 (manufactured by Waters), and as the columns, PLgel, 5 μm, MIXED-D (manufactured by Polymer Laboratories), TSKgel Super AW series (manufactured by Tosoh Corporation), TSKgel Super H series (manufactured by Tosoh Corporation), etc. can be used. As the developing solvent, tetrahydrofuran, 1,2,4-trichlorobenzene, N,N-dimethylformamide (added with 0.01N lithium bromide), etc. can be used, and the flow rate is preferably from 0.5 to 1.5 milliliters / minute. For detection, an RI detector or the like can be used, and the measurement can be carried out under conditions such as a sample injection concentration of 0.5 to 1.5 milligrams / milliliter and an injection volume of 0.1 to 1.0 microliters. The weight average molecular weight can be determined as a polystyrene equivalent value.

[0064] The molecular weight distribution (Mw / Mn) of the polyester-based urethane resin (B) and other urethane resins is preferably from 2.0 to 8.0, more preferably from 2.5 to 7.0, and even more preferably from 3.0 to 6.0. Mw represents the weight average molecular weight, and Mn represents the number average molecular weight. When Mw / Mn is within the above range, it is considered that the cohesive force and adhesion are strengthened by crosslinking with the isocyanate-based curing agent described below, and easy tearability is exhibited. Note that Mw, Mn, and Mw / Mn can be determined by gel permeation chromatography (GPC) as described above.

[0065] In order to make the molecular weight distribution (Mw / Mn) of the polyester-based urethane resin (B) and other urethane resins fall within the above range, in the synthesis of urethane resins, methods such as selecting urethane synthesis raw materials, setting the solid content mass ratio, controlling the dropping rate of reactive raw materials such as polyisocyanates in the synthesis reaction, the stirring rate and the shape of the stirring blades, and appropriately setting the reaction temperature can be selected. In addition, when further performing a chain extension reaction, in particular, setting a certain range for the dropping rate and temperature range control when reacting polyamine with a urethane prepolymer is effective in making the molecular weight distribution fall within a predetermined range. Controlling the reaction temperature is important. In the synthesis of the urethane prepolymer, it is preferably controlled between 50 and 130 °C, and when reacting polyamine with the urethane prepolymer, it is preferably controlled within the range of 10 to 50 °C. In addition, setting the charging ratio of the reaction raw materials to an appropriate ratio is also effective in making the molecular weight distribution fall within a predetermined range. The charging ratio refers to, for example, the ratio of the hydroxyl groups of polyol and hydroxy acid, and further the isocyanate groups of polyisocyanate, such as the NCO / OH ratio, and the ratio of the amino groups of polyamine to the isocyanate groups of the urethane prepolymer, such as the amino group / NCO ratio. In addition, in order to control the molecular weight distribution, it is preferable to use a reaction terminator as described above for the purpose of preventing excessive polymerization reaction.

[0066] [Resin L] When the binder resin contains a urethane resin, the binder resin preferably further contains a resin other than the urethane resin (referred to as resin L). Resin L is preferably at least one resin selected from the group consisting of polyvinyl acetal resins, cellulose-based resins, rosin-based resins, and acrylic resins. More preferably, it is a resin having a ring structure, and still more preferably, it is a resin having at least one ring structure selected from the group consisting of an acetal ring structure, an aromatic ring structure, an alicyclic ring structure, and a pyranose ring structure. Particularly preferably, it is a resin having an acetal ring structure. These ring structures may have a double bond or may have an alkyl group or other substituents.

[0067] Resin L contains a structural unit having a ring structure, preferably in the range of 40 to 95% by mass, more preferably in the range of 50 to 90% by mass, based on the mass of Resin L. When Resin L contains a structural unit having a ring structure within the above range, pigment dispersion in the printing ink is promoted. Also, it has excellent laminate strength for the packaging material and can suppress deterioration over time. Furthermore, it becomes excellent in blocking resistance. In this specification, the mass of the monomer having a ring structure includes groups substituted or adjacent to the ring structure such as a methyl group or a nitro group. For example, when Resin L is a styrene-acrylic resin, and the structural unit derived from α-methylstyrene is 50% by mass and the structural unit derived from butyl methacrylate which is an acrylic monomer is 50% by mass, the content of the ring structure is 50% by mass.

[0068] The content of the structural unit having a ring structure may be calculated by the following formula. Formula: Content of the structural unit having a ring structure (% by mass) = Mass of the monomer having a ring structure × 100 / Total mass of all monomers constituting Resin L

[0069] Examples of the resin having a ring structure include polyvinyl acetal resin, cellulose ester resin, rosin resin, polystyrene resin, polyester resin having a ring structure, acrylic resin having a ring structure, and copolymer resins thereof. More preferably, it contains at least one selected from the group consisting of polyvinyl acetal resin, cellulose ester resin, rosin resin, and acrylic resin having a ring structure. Even more preferably, it contains polyvinyl acetal resin.

[0070] ≪Polyvinyl acetal resin≫ The above polyvinyl acetal resin is obtained by reacting polyvinyl alcohol with an aldehyde such as butyraldehyde and / or formaldehyde to cause acetal cyclization, and preferably contains vinyl alcohol units, vinyl acetate units and acetal ring groups. The polyvinyl acetal resin preferably contains 60 to 90% by mass of acetal rings, 5 to 30% by mass of vinyl alcohol units, and 0.5 to 10% by mass of vinyl acetate units, and more preferably is a polyvinyl butyral resin having a butyral ring as the acetal ring. The weight average molecular weight of the polyvinyl acetal resin is preferably 10,000 to 100,000, more preferably 10,000 to 80,000. The glass transition point of the polyvinyl acetal resin is preferably 50 to 80°C, more preferably 60 to 75°C.

[0071] ≪Cellulose ester resin≫ Preferably, the cellulose ester resin is a cellulose acetate alkynate resin, and for example, cellulose acetate propionate and cellulose acetate butyrate are preferably used. The cellulose ester resin preferably has an alkyl group. The above alkyl group is preferably an alkyl group having 10 or less carbon atoms, and for example, a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a pentyl group, and a hexyl group are preferably used. The alkyl group may have a substituent. The weight average molecular weight of the cellulose ester resin is preferably 5,000 to 200,000, more preferably 10,000 to 100,000, and still more preferably 15,000 to 80,000. The glass transition point of the cellulose ester resin is preferably 120°C to 180°C, more preferably 130 to 170°C. By using the urethane resin and the cellulose ester resin in combination, printability, blocking resistance, etc. are improved.

[0072] ≪Rosin resin≫ A rosin resin refers to a resin having, as a main component, a structural unit derived from rosin acid (e.g., abietic acid, neoabietic acid, palustric acid, pimaric acid, isopimaric acid, dehydroabietic acid). Here, the main component means 50% by mass or more. The rosin acid or rosin resin may be hydrogenated. Preferably, the rosin resin is at least one selected from the group consisting of rosin-modified phenol resins, rosin ester resins, rosin-modified maleic acid resins, and polymerized rosin resins. The acid value of the rosin resin is preferably 350 mgKOH / g or less, more preferably 250 mgKOH / g or less, and even more preferably 150 mgKOH / g or less. In one embodiment, the acid value is preferably 100 mgKOH / g or less, and more preferably 50 mgKOH / g or less. The softening point of the rosin resin is preferably 60 to 180°C, more preferably 70 to 150°C. In this specification, the softening point is a measured value by the ring and ball method and can be measured in accordance with JIS K2207.

[0073] ≪Rosin Ester≫ As the rosin resin, a rosin ester which is an ester condensation resin of a low molecular polyol having a molecular weight of 1,000 or less and rosin acid is preferable. The low molecular polyol preferably has 2 to 4 hydroxyl groups in one molecule (hereinafter may be abbreviated as 2 to 4 functional) and a molecular weight of 50 to 500. Examples of such low molecular polyols include bifunctional low molecular polyols such as ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,10-decanediol; trifunctional low molecular polyols such as glycerin, trimethylolpropane; tetrafunctional low molecular polyols such as erythritol, pentaerythritol; are preferably used. Among them, trifunctional and / or tetrafunctional low molecular polyols are preferable. The weight average molecular weight of the rosin ester is preferably 500 to 2,000, more preferably 500 to 1,500.

[0074] ≪Acrylic Resin≫ As the acrylic resin, an acrylic resin having a glass transition temperature of 40 to 100°C is preferably used.

[0075] In this specification, the “acrylic resin” means a polymer having an acrylic monomer as a constituent unit. Further, the “acrylic monomer” means a monomer having an acrylic group or a methacryloyl group, and “methacrylic and acrylic” may be collectively referred to as “(meth)acrylic” for short. Also, “methacrylate and acrylate” may be collectively referred to as “(meth)acrylate” for short.

[0076] Hereinafter, the acrylic monomers constituting the acrylic resin are listed, which is an example of the embodiment and is not particularly limited. The acrylic monomers may be used alone or in combination of two or more.

[0077] For example, as the alkyl (meth)acrylate, methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, cyclohexyl (meth)acrylate, cyclopentyl (meth)acrylate, methylcyclohexyl (meth)acrylate, bornyl (meth)acrylate, isobornyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentanyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isooctyl (meth)acrylate, decyl (meth)acrylate, dodecyl (meth)acrylate, tetradecyl (meth)acrylate, hexadecyl (meth)acrylate, octadecyl (meth)acrylate, etc. may be mentioned. Among these, methyl (meth)acrylate is preferable.

[0078] For example, in order to obtain the acrylic resin having the above ring structure, an aromatic ring-containing acrylic monomer can be used. Examples of the aromatic ring-containing acrylic monomer include phenyl (meth) acrylate, benzyl (meth) acrylate, phenoxymethyl (meth) acrylate, phenoxyethyl (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, and the like.

[0079] The glass transition temperature (Tg) of the acrylic resin is in the range of 40 to 100°C, preferably 40 to 90°C, and more preferably 40 to 80°C.

[0080] The weight average molecular weight (Mw) of the acrylic resin is preferably 20,000 to 300,000.

[0081] [Chlorine content of the binder resin] In the present invention, the chlorine content of the binder resin is preferably 5% by mass or less, including the case of 0. The above chlorine content is more preferably 4% by mass or less, still more preferably 3% by mass or less, and particularly preferably 2% by mass or less. Also, forms of 1% by mass or less or 0.5% by mass or less are particularly preferred. The above chlorine content is the content rate (mass%) of chlorine atoms based on the mass of the binder resin. When the chlorine content is 5% by mass or less, the environmental safety is excellent and the generation of free chlorine is difficult.

[0082] The above chlorine content can be measured using known methods such as ion chromatography (IC) and ICP mass spectrometer (ICP-MS). Examples of the measuring instrument include LC-20ADsp manufactured by Shimadzu Corporation for IC and Agilent 7700x manufactured by Agilent Technologies for ICP-MS. Also, the chlorine content of the printing layer can be simply calculated from the chlorine contents of the respective raw materials constituting the printing layer by the following formula. The same applies to other layers. Formula: Chlorine content rate (%) in the total solid mass of the binder resin = Mass of chlorine in the total solid mass of the binder resin / Total solid mass of the binder resin (%) Formula: Chlorine content rate (%) in the total solid mass of the printing layer = Mass of chlorine in the total solid mass of the printing layer / Total solid mass of the printing layer (%)

[0083] In the present invention, the chlorine content rate is preferably measured in accordance with JIS K0127 (2013). In this measurement method, a sample pretreated by a combustion method is quantified by ion chromatography.

[0084] [Degree of nitration of the binder resin] In the binder resin of the present invention, the degree of nitration is preferably 1 mass% or less, including the case of 0. By having a degree of nitration of 1 mass% or less, generation of NOx gas can be suppressed, and a more safe recycling material can be provided. Note that the degree of nitration is the degree of esterification of the nitrate ester represented by the nitrogen content (mass%), and for example, commercially available nitrocellulose is usually 10 to 12 mass%. The degree of nitration of the binder resin is more preferably 0.6 mass% or less, still more preferably 0.4 mass% or less, and particularly preferably 0.2 mass% or less. Note that the degree of nitration of the urethane resin is preferably 0.3 mass% or less, still preferably 0.2 mass% or less, and even more preferably 0.1 mass% or less. Also, the degree of nitration of the resin L is preferably 0.8 mass% or less, still preferably 0.6 mass%, and even more preferably 0.4 mass%.

[0085] (Isocyanate curing agent) In the packaging material of the present invention, in order to improve the laminate physical properties and tearability, the printing ink used for forming the printing layer preferably contains an isocyanate-based curing agent. When the binder resin has a hydroxyl group, an amino group, or other active hydrogen groups, the isocyanate-based curing agent crosslinks with the active hydrogen groups. When the binder resin does not have the active hydrogen groups, it is considered that the laminate strength, easy tearability, etc. are improved by self-crosslinking only with the isocyanate-based curing agent.

[0086] Preferred embodiments of the isocyanate-based curing agent are shown below. The weight average molecular weight of the isocyanate-based curing agent is preferably 800 to 8000, more preferably 1000 to 4500, and still more preferably 1500 to 4000. Further, the molecular weight distribution (Mw / Mn) of the isocyanate-based curing agent is preferably 2.0 to 5.0, still more preferably 2.2 to 4.5, and even more preferably 2.5 to 4.0. When the weight average molecular weight, and further Mw / Mn, are within the above ranges, it is considered that the cohesive force and adhesion of the printing ink are enhanced by the action with the urethane resin, and good laminate strength and easy tearability are exhibited.

[0087] As the isocyanate-based curing agent, polyisocyanates including adduct-type polyisocyanates (adducts), biuret-type polyisocyanates (biurets), isocyanurate-type polyisocyanates (isocyanurates), bifunctional polyisocyanates, etc. are preferable. Examples of the adducts, biurets, and isocyanurates include adducts obtained from the reaction of trimethylolpropane or other polyols with diisocyanates, biurets in which diisocyanates are dimerized and linked by biuret bonds, isocyanurates obtained from the cyclic trimerization reaction of diisocyanates, and the like. As the diisocyanate, any of the above-described diisocyanates may be arbitrarily selected and used. Among them, tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), hydrogenated diphenylmethane diisocyanate (hydrogenated MDI), hexamethylene diisocyanate (HDI), isophorone diisocyanate, xylylene diisocyanate (XDI), hydrogenated xylylene diisocyanate (hydrogenated XDI), etc. are preferably mentioned. The adduct-type polyisocyanate, biuret-type polyisocyanate, and isocyanurate-type polyisocyanate may be used in combination, and may further be used in combination with other polyisocyanates.

[0088] In order to make the weight average molecular weight and molecular weight distribution (Mw / Mn) of the isocyanate-based curing agent fall within the above ranges, in the synthesis of the isocyanate-based curing agent, the selection of diisocyanates, polyols, etc., the solid content mass ratio, the dropping rate of reactive raw materials such as polyisocyanates in the synthesis reaction, the stirring rate, the shape of the stirring blades, and further the reaction temperature can be set appropriately to be within the ranges. In addition, setting the dropping rate and temperature range control when reacting polyamine and polyisocyanate within a certain range is effective for making the molecular weight distribution fall within a predetermined range. In addition, it is effective to set the charging ratio of the reaction raw materials to an appropriate ratio to make the molecular weight distribution within a predetermined range. The charging ratio refers to, for example, the ratio of isocyanate groups of polyol and polyisocyanate, such as the NCO / OH ratio, and the ratio of amino groups of polyamine and isocyanate groups of polyisocyanate, such as the amino group / NCO ratio. Controlling the reaction temperature is important. In the synthesis using polyol and polyisocyanate, it is preferably controlled between 50 and 130 °C, and when reacting polyamine and polyisocyanate, it is preferably controlled within the range of 10 to 50 °C. Also, the solid content is important, and it is preferably 40 to 80% by mass of the solid content during the reaction. The reaction solvent is also important, and it is preferable to use ethyl acetate, normal propyl acetate and other ester-based organic solvents.

[0089] In addition, when the binder resin contains a urethane resin, the mass ratio of the urethane resin to the isocyanate-based curing agent (urethane resin: isocyanate-based curing agent) is preferably 99:1 to 60:40, more preferably 98:2 to 65:35, and still more preferably 95:5 to 70:30. When the binder resin contains resin L in addition to the urethane resin, the mass ratio of the total amount of the urethane resin and resin L to the isocyanate-based curing agent is preferably 99:1 to 60:40, and still more preferably 95:5 to 70:30. This is because within this range, the effects of the above cross-linking and substrate adhesion are good, and it is considered that good laminate physical properties and easy tearability are exhibited.

[0090] (organic solvent) The printing ink used for forming the printing layer preferably contains an organic solvent as a liquid medium. As the organic solvent used in the ink, it is preferably used as a mixed solvent, and known organic solvents such as aromatic organic solvents such as toluene and xylene, ketone organic solvents such as methyl ethyl ketone and methyl isobutyl ketone, ethyl acetate, n-propyl acetate, isopropyl acetate, isobutyl acetate, ester organic solvents, and alcohol organic solvents such as methanol, ethanol, n-propanol, isopropanol, and n-butanol can be used. Among them, an organic solvent (non-toluene-based organic solvent) that does not contain aromatic organic solvents such as toluene and xylene is more preferable. More preferably, it is an organic solvent that does not contain aromatic organic solvents and / or ketone organic solvents such as methyl ethyl ketone (hereinafter referred to as "MEK"), and it is preferable that the ester organic solvent is contained as a main component (50% or more) in the organic solvent. In particular, those containing an ester organic solvent and an alcohol organic solvent are preferable.

[0091] (Additive) In the printing ink used for forming the printing layer, furthermore, if necessary, for example, any additives such as leveling agents, defoamers, waxes, silane coupling agents, fillers, stabilizers, plasticizers, antioxidants, light stabilizers such as ultraviolet absorbers, dispersants, thickeners, desiccants, lubricants, antistatic agents, and crosslinking agents can be added.

[0092] (Gravure printing) The printing ink used for forming the printing layer is preferably gravure ink or flexo ink, and still more preferably gravure ink. Also, the printing layer is preferably formed by a gravure printing method or a flexo printing method, and more preferably formed by a gravure printing method.

[0093] (Gravure plate) In the above gravure printing method, the gravure plate is a cylindrical metal one, and recesses for each color are formed by engraving, etching, or laser. There are no restrictions on the use of engraving and laser, and they can be arbitrarily set according to the pattern. As the line count, those with 100 to 300 lines are appropriately used, and the larger the line count, the finer the printing can be. As the thickness of the printing layer, 0.1 μm to 100 μm is preferable.

[0094] (Gravure printing machine) In the above gravure printing method, one printing unit in the gravure printing machine is equipped with the above gravure plate and doctor blade. There are multiple printing units, and printing units corresponding to organic solvent-based printing ink and pattern ink can be set, and each unit has an oven drying unit. Printing is performed by rotation and is a roll-to-roll printing method. The type of plate and the type of doctor blade are appropriately selected, and those corresponding to the specifications can be selected.

[0095] (Adhesive layer) The adhesive layer in the present invention is composed of a cured product of a reactive adhesive containing a polyol compound (D) and an isocyanate compound (I).

[0096] (Polyol compound (D)) The polyol compound (D) is not particularly limited. For example, in addition to polyester polyols, polyether polyols, polyurethane polyols, polyester amide polyols, acrylic polyols, polycarbonate polyols, polycaprolactone polyols, polyvalerolactone polyols, polyolefin polyols, polyhydroxyalkanes, castor oil, or mixtures thereof, glycols such as ethylene glycol, propylene glycol, 1,3 - propanediol, 1,4 - butanediol, 1,5 - pentanediol, 3 - methyl - 5 - pentanediol, 1,6 - hexanediol, neopentyl glycol, methylpentanediol, triethylene glycol, tetraethylene glycol, dipropylene glycol, bishydroxyethoxybenzene, 1,4 - cyclohexanediol, 1,4 - cyclohexanedimethanol, triethylene glycol; polyalkylene glycols with a number - average molecular weight of 200 to 3,000; trifunctional or tetrafunctional aliphatic alcohols such as glycerin, trimethylolpropane, pentaerythritol; polyols obtained by adding the above - mentioned glycol or polyol to the above - mentioned trifunctional or tetrafunctional aliphatic alcohol can be used. These can be used alone or in combination of two or more.

[0097] Preferably, the polyol compound (D) contains structural units derived from polyester polyols or structural units derived from polyether polyols. It may also be a polyester polyol or a polyether polyol itself. Among them, it is preferable that the polyol compound (D) is a urethane polyol containing a urethane structure.

[0098] Examples of the polyester polyol include a polyester polyol obtained by subjecting a dibasic acid such as terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, phthalic anhydride, adipic acid, azelaic acid, sebacic acid, succinic acid, glutaric acid, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, maleic anhydride, itaconic anhydride or a dialkyl ester thereof or a mixture thereof (hereinafter also referred to as a carboxyl group component) and a diol such as ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, triethylene glycol, butylene glycol, neopentyl glycol, dineopentyl glycol, trimethylolpropane, glycerin, 1,6 - hexanediol, 1,4 - butanediol, 1,4 - cyclohexanedimethanol, 3 - methyl - 1,5 - pentanediol, 3,3'-dimethylolheptane, 1,9 - nonanediol, polyoxyethylene glycol, polyoxypropylene glycol, polytetramethylene ether glycol, polyether polyol, polycarbonate polyol, polyolefin polyol, acrylic polyol, polyurethane polyol or a mixture thereof (hereinafter also referred to as a hydroxyl group component) to an esterification reaction; and a polyester polyol obtained by ring - opening polymerization of lactones such as polycaprolactone, polyvalerolactone, poly(β - methyl - γ - valerolactone). The above - mentioned carboxyl group component and hydroxyl group component may be used in combination of two or more kinds.

[0099] Examples of the polyether polyol include polyether diol, polyether triol and the like. For example, a polyether diol obtained by polymerizing an oxirane compound such as ethylene oxide, propylene oxide, butylene oxide, tetrahydrofuran using water, a bifunctional low - molecular - weight polyol such as ethylene glycol, propylene glycol as an initiator; and a polyether triol obtained by polymerizing an oxirane compound such as ethylene oxide, propylene oxide, butylene oxide, tetrahydrofuran using a low - molecular - weight triol such as trimethylolpropane, glycerin as an initiator.

[0100] The polyol compound (D) containing a structural unit derived from the above polyester polyol or a structural unit derived from the polyether polyol may be a polyester urethane polyol or a polyether urethane polyol obtained by further reacting the above polyester polyol or polyether polyol with a diisocyanate, or may be a product obtained by further reacting an acid anhydride. Examples of the above diisocyanate include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, xylylene diisocyanate, diphenylmethane diisocyanate, isophorone diisocyanate, 1,5-naphthalene diisocyanate, hexamethylene diisocyanate, and hydrogenated diphenylmethane diisocyanate. Examples of the above acid anhydride include pyromellitic anhydride, mellitic anhydride, trimellitic anhydride, and trimellitic acid ester anhydride. Examples of the trimellitic acid ester anhydride include ethylene glycol bisanhydrotrimellitate and propylene glycol bisanhydrotrimellitate.

[0101] The weight average molecular weight (Mw) of the polyol compound (D) is preferably from 2,000 to 80,000, more preferably from 5,000 to 60,000, and still more preferably from 10,000 to 60,000. Also, by using a polyol compound (D) having a molecular weight distribution (Mw / Mn) of 1.5 to 10, the leveling property during adhesive coating and the adhesion between layers can be improved. In particular, when the polyol compound contains a structural unit derived from a polyether polyol, its molecular weight distribution (Mw / Mn) is preferably from 3.0 to 10.0, more preferably from 3.0 to 8.0. When it contains a structural unit derived from a polyester polyol, its molecular weight distribution (Mw / Mn) is preferably from 1.5 to 5.0, more preferably from 2.0 to 4.0.

[0102] The acid value of the polyol compound (D) is not particularly limited, but is preferably 0 to 50 mgKOH / g, more preferably 0 to 40 mgKOH / g. The hydroxyl value of the polyol compound (D) is not particularly limited, but is preferably 1 to 200 mgKOH / g, more preferably 3 to 150 mgKOH / g.

[0103] (Isocyanate compound (I)) The isocyanate compound (I) functions as a curing agent in the reactive adhesive and can be used without limitation for ordinary two-component reactive adhesives as long as it contains a functional group having reactivity with a hydroxyl group. By having an isocyanate group, the adhesive strength and cohesion of the adhesive are increased, and curing can be carried out at a low temperature near room temperature.

[0104] As the isocyanate compound (I), a diisocyanate or a urethane prepolymer which is a reaction product of a diisocyanate and a polyol is preferable. As such diisocyanates, various known aromatic, aliphatic or alicyclic diisocyanates can be used. For example, 1,5-naphthylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 4,4'-diphenyldimethylmethane diisocyanate, 4,4'-dibenzyl isocyanate, dialkyldiphenylmethane diisocyanate, tetraalkyldiphenylmethane diisocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, tolylene diisocyanate, butane-1,4-diisocyanate, hexamethylene diisocyanate, isopropylene diisocyanate, methylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, cyclohexane-1,4-diisocyanate, xylylene diisocyanate, isophorone diisocyanate, lysine diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, 1,3-bis(isocyanatomethyl)cyclohexane, methylcyclohexane diisocyanate, m-tetramethylxylylene diisocyanate, and dimer diisocyanate obtained by converting the carboxyl group of dimer acid into an isocyanate group are mentioned as typical examples. These can be used alone or in admixture of two or more. Among these, from the viewpoints of yellowing and imparting flexibility for improving adhesion, the use of aliphatic diisocyanates such as hexamethylene diisocyanate and xylylene diisocyanate, and alicyclic diisocyanates such as isophorone diisocyanate is preferable. From the viewpoint of compatibility with retort resistance, it is preferably used as a polyisocyanate compound having three or more functional groups such as an adduct body of trimethylolpropane or an isocyanurate body or a biuret body.

[0105] In one embodiment, the polyol compound (D) and the isocyanate compound (I) are preferably used such that the functional group equivalent ratio NCO / OH of the hydroxyl group derived from the polyol and the isocyanate group derived from the isocyanate is 1.5 to 8.0, and more preferably 2.0 to 5.0. In addition, components known as adhesive components can be incorporated into the main agent or the curing agent of the reactive adhesive.

[0106] (Reaction accelerator) The reactive adhesive can contain, for example, a reaction accelerator. Examples of the reaction accelerator include metal catalysts such as dibutyltin diacetate, dibutyltin dilaurate, dioctyltin dilaurate, and dibutyltin dimaleate; tertiary amines such as 1,8-diazabicyclo(5,4,0)undecene-7, 1,5-diazabicyclo(4,3,0)nonene-5, and 6-dibutylamino-1,8-diazabicyclo(5,4,0)undecene-7; reactive tertiary amines such as triethanolamine; and titanium-based, zinc-based, and bismuth-based compounds. These can be used alone or in any combination of two or more. Among them, the use of titanium-based, zinc-based, and bismuth-based compounds is preferred because the aging effect and the resistance to the contents of the adhesive are excellent.

[0107] (Silane coupling agent) From the viewpoint of improving the adhesive strength to metal-based materials such as inorganic vapor deposition layers and metal foils, the reactive adhesive can contain a silane coupling agent. Examples of the silane coupling agent include trialkoxysilanes having a vinyl group such as vinyltriethoxysilane; trialkoxysilanes having an amino group such as 3-aminopropyltriethoxysilane and N-(2-aminoethyl)-3-aminopropyltrimethoxysilane; and trialkoxysilanes having a glycidyl group such as 3-glycidoxypropyltrimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, and 3-glycidoxypropyltriethoxysilane. These can be used alone or in any combination of two or more. The content of the silane coupling agent is preferably 0.01 to 5% by mass, more preferably 0.02 to 3% by mass, based on the total polyol component. By setting it within the above range, the adhesive strength to the inorganic vapor deposition layer or the metal foil can be improved.

[0108] (Phosphoric acid or a phosphoric acid derivative) The reactive adhesive can contain phosphoric acid or a phosphoric acid derivative from the viewpoint of improving the adhesive strength to a metal-based material such as a metal foil. The phosphoric acid may be any one having at least one free oxyacid, for example, phosphorous acids such as hypophosphorous acid, phosphorous acid, orthophosphoric acid, and metaphosphoric acid; condensed phosphoric acids such as metaphosphoric acid, pyrophosphoric acid, tripolyphosphoric acid, polyphosphoric acid, and ultraphosphoric acid; may be mentioned. Further, examples of the derivative of phosphoric acid include those obtained by partially esterifying the above-mentioned phosphoric acid with alcohols while leaving at least one free oxyacid. Examples of the alcohols include aliphatic alcohols such as methanol, ethanol, ethylene glycol, and glycerin; aromatic alcohols such as phenol, xylenol, hydroquinone, catechol, and phloroglucinol; These can be used alone or in any combination of two or more. The content of phosphoric acid or its derivative is preferably 0.01 to 10% by mass, more preferably 0.05 to 5% by mass, still more preferably 0.05 to 1% by mass, based on the solid content of the reactive adhesive.

[0109] (Leveling agent, defoaming agent) The reactive adhesive can contain known leveling agents or defoaming agents for the purpose of improving the laminate appearance. Examples of the leveling agent include polyether-modified polydimethylsiloxane, polyester-modified polydimethylsiloxane, aralkyl-modified polymethylalkylsiloxane, polyester-modified hydroxyl group-containing polydimethylsiloxane, polyether ester-modified hydroxyl group-containing polydimethylsiloxane, acrylic copolymers, methacrylic copolymers, polyether-modified polymethylalkylsiloxane, alkyl acrylate copolymers, alkyl methacrylate copolymers, and lecithin. Examples of the defoaming agent include silicone resins, silicone solutions, and copolymers of alkyl vinyl ether, alkyl acrylate, and alkyl methacrylate. These can be used alone or in any combination of two or more. The content of the leveling agent and the defoaming agent is preferably 0.001 to 1% by mass, more preferably 0.005 to 0.5% by mass, based on the solid content of the reactive adhesive.

[0110] (Other additives) In the reactive adhesive, various additives may be blended as long as the effects of the present invention are not impaired. Examples of the additives include inorganic fillers such as silica, alumina, mica, talc, aluminum flakes, and glass flakes, layered inorganic compounds, stabilizers (antioxidants, heat stabilizers, ultraviolet absorbers, hydrolysis inhibitors, etc.), rust inhibitors, thickeners, plasticizers, antistatic agents, lubricants, anti-blocking agents, colorants, fillers, crystal nucleating agents, and catalysts for adjusting the curing reaction.

[0111] (Organic solvents) The reactive adhesive may be diluted with a solvent to adjust its viscosity to an appropriate level. As the organic solvent used in the reactive adhesive, those inert to the polyisocyanate component, such as ester-based ones like ethyl acetate, ketone-based ones like methyl ethyl ketone, and aromatic hydrocarbon-based ones like toluene and xylene, are preferably used and can be appropriately selected and used.

[0112] <Intermediate substrate> The packaging material of the present invention may further have an intermediate substrate layer. The intermediate substrate preferably contains a polyolefin resin. Furthermore, in the total mass of the intermediate substrate, it is preferable that the polyolefin resin is 50% by mass or more, more preferably 60% by mass or more, still more preferably 70% by mass or more, further preferably 80% by mass or more, and particularly preferably 90% by mass or more. Moreover, it is more preferable that the polyolefin resin is a polypropylene-based resin and / or a polyethylene-based resin, still more preferably that the polyolefin resin is a polypropylene-based resin, and particularly preferably that the polypropylene-based resin is a copolymer with ethylene and / or butene. Examples of the intermediate substrate include polyolefin resins such as low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), medium-density polyethylene (MDPE), high-density polyethylene (HDPE), ethylene-vinyl acetate copolymer, propylene homopolymer, and ethylene-propylene copolymer. A form that is a gas barrier substrate, for example, a plastic substrate having an inorganic vapor deposition layer such as aluminum, silica, or alumina, or a plastic substrate having a layer in which organic and inorganic components are mixed, is preferable.

[0113] <Sealant> The sealant has a role of protecting the packaged product with the inner layer side surface directly contacting the packaged product. In order to make the laminate into a bag shape, it is preferable that the innermost layer of the sealant has heat sealability. The sealant preferably contains a polyolefin resin. Furthermore, in the total mass of the sealant, it is preferable that the polyolefin resin is 50% by mass or more, more preferably 60% by mass or more, still more preferably 70% by mass or more, further preferably 80% by mass or more, and particularly preferably 90% by mass or more. Moreover, it is more preferable that the polyolefin resin is a polypropylene-based resin and / or a polyethylene-based resin, still more preferably that the polyolefin resin is a polypropylene-based resin, and particularly preferably that the polypropylene-based resin is a copolymer with ethylene and / or butene. Examples of the material constituting the sealant include polyolefin resins such as low density polyethylene (LDPE), linear low density polyethylene (LLDPE), medium density polyethylene (MDPE), high density polyethylene (HDPE), ethylene-vinyl acetate copolymer, propylene homopolymer, and ethylene-propylene copolymer, and one or more of these resins can be used. The sealant may be composed of a single layer or multiple layers of two or more layers. In addition, the sealant is preferably an unstretched film made of the above-mentioned resin in order to suppress shrinkage during heat sealing.

[0114] The thickness of the sealant is not particularly limited and is appropriately set according to the use of the laminate and the type and properties of the packaged product, etc., but usually it is preferably 10 to 200 μm. Also, in the case of a pouch (especially a retort pouch), the thickness of the sealant is preferably 20 to 150 μm, more preferably 25 to 130 μm.

[0115] The sealant may be, for example, a sealant having an inorganic vapor deposition layer such as aluminum, silica, and alumina, or an organic layer such as ethylene-vinyl alcohol copolymer and polyvinyl alcohol. It may also be an opacified base material kneaded with a pigment or the like, or a composite base material by coextrusion.

[0116] <Method for manufacturing packaging material> The method for manufacturing the packaging material of the present invention preferably includes a step of printing a gravure ink containing a polyester-based urethane resin (B) on a substrate to form a printed layer, and a step of applying a reactive adhesive containing a polyol compound (D) and an isocyanate compound (I) to form an adhesive layer. The adhesive layer may be formed by applying it on the printed layer or on the sealant.

[0117] As a suitable embodiment, for example, an adhesive is applied and formed on the above printing layer, and then a sealant is laminated. In addition, when the packaging material further has an intermediate base material layer, it is preferable to include a step of once laminating the printing layer and the intermediate base material with an adhesive, and then laminating the intermediate base material and the sealant. Note that the above configuration is arbitrary and not particularly limited.

[0118] The method for applying and forming the adhesive is not particularly limited. Examples of the apparatus for applying the adhesive composition include a comma coater, a dry laminator, a roll knife coater, a die coater, a roll coater, a bar coater, a gravure roll coater, a reverse roll coater, a blade coater, a gravure coater, and a micro gravure coater. The solid content coating amount of the adhesive composition is not particularly limited and can be appropriately selected according to the use. Usually, it is in the range of 0.5 to 6.0 g / m 2 When the adhesive composition is a solvent-free type, it is 1.0 to 3.0 g / m 2 When it is a solvent type, a range of 1.0 to 5.0 g / m 2 is preferably used.

[0119] The packaging material thus obtained is cut into a predetermined size, and the edge portions are heat-sealed in a form where the sealants are aligned with each other to form a bag shape. The heat-sealing temperature is preferably 50 to 250 °C, and more preferably 80 to 180 °C. The heat-sealing pressure may be conditions such as 1 to 5 kg / cm 2 or the like. One packaging material may be bent and the edge heat-sealed, or two or more packaging materials may be heat-sealed. Also, the bag made of the packaging material may be one in which all openings are heat-sealed after packaging the contents.

Example

[0120] Hereinafter, the present invention will be described in detail with reference to examples, but the present invention is not limited to these examples. In the present invention, "parts" and "%" represent parts by mass and mass%, respectively, unless otherwise specified.

[0121] <Method for Measuring Amine Value> The amine value was determined according to the following method in accordance with JIS K0070 as the number of mg of potassium hydroxide equivalent to the amount of hydrochloric acid required to neutralize the amino groups contained in 1 g of the resin. A sample was accurately weighed at 0.5 to 2 g (sample solid content: S g). 50 mL of a mixed solution of methanol / methyl ethyl ketone = 60 / 40 (mass ratio) was added to the accurately weighed sample and dissolved. Bromophenol blue was added as an indicator to the resulting solution, and the resulting solution was titrated with a 0.2 mol / L ethanolic hydrochloric acid solution (titer: f). The point at which the color of the solution changed from green to yellow was taken as the end point, and using the titration volume (A mL) at this time, the amine value was determined by the following (Equation 1). (Equation 1) Amine value = (A × f × 0.2 × 56.108) / S [mg KOH / g]

[0122] <Weight-Average Molecular Weight Mw, Number-Average Molecular Weight Mn, and Molecular Weight Distribution Mw / Mn> The weight-average molecular weight Mw, number-average molecular weight Mn, and molecular weight distribution Mw / Mn were determined as the converted molecular weights using a GPC (gel permeation chromatography) apparatus (HLC-8220 manufactured by Tosoh Corporation) with polystyrene as the standard substance. The measurement conditions are shown below. Column: The following columns were connected in series and used. TSKgel SuperHM-L manufactured by Tosoh Corporation TSKgel SuperHM-L manufactured by Tosoh Corporation TSKgel SuperHM-M manufactured by Tosoh Corporation TSKgel guard column SuperH-H manufactured by Tosoh Corporation Detector: RI (differential refractometer) Measurement conditions: Column temperature 40°C Eluent: Tetrahydrofuran Flow rate: 1.0 mL / min

[0123] <Method for measuring hydroxyl value> It was determined according to the method described in JIS K0070.

[0124] <Method for measuring acid value> It was determined according to the method described in JIS K0070.

[0125] [Synthesis Example 1-1] (Synthesis of polyester polyol A1) Into a round-bottom flask equipped with a stirrer, thermometer, water separator and nitrogen gas inlet tube, 26 parts of 1,3-propanediol (hereinafter also abbreviated as 1,3-PD), 26 parts of neopentyl glycol (hereinafter also abbreviated as NPG), 48 parts of sebacic acid, and 0.002 part of tetrabutyl titanate were charged, and esterification was carried out for 8 hours while removing the water generated by condensation at 230 °C under a nitrogen stream. After confirming that the acid value of the polyester was 15 or less, the degree of vacuum was gradually increased by a vacuum pump to terminate the reaction. Thus, a polyester polyol A1 having a number average molecular weight of 2000, a hydroxyl value of 56.1 mg KOH / g, and an acid value of 0.3 mg KOH / g was obtained.

[0126] [Synthesis Examples 1-2 and 1-3] (Synthesis of polyester polyols A2 and A3) Polyester polyols A2 to A3 were obtained in the same manner as in Synthesis Example 1-1 except that the raw materials and charging ratios shown in Table 1 were used. The abbreviations shown in the table represent the following. NPG: Neopentyl glycol, PG: 1,2-propylene glycol, 1,3-PD: 1,3-propanediol

[0127] [Table 1]

[0128] [Synthesis Example 2-1] (Synthesis of polyester urethane resin B1) Into a four-necked flask equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen gas inlet tube, 23.6 parts of polyester polyol A1, 4.68 parts of isophorone diisocyanate (hereinafter also abbreviated as IPDI), 7.5 parts of ethyl acetate, and 0.003 part of tin 2-ethylhexanoate were charged, and the mixture was reacted at 120 °C for 6 hours under a nitrogen stream. Then, 7.5 parts of propyl acetate was added and the mixture was cooled to obtain a solution of a terminal isocyanate prepolymer. Next, 1.60 parts of isophoronediamine (hereinafter also abbreviated as IPDA), 0.12 part of dibutylamine (hereinafter also abbreviated as DBA), 34 parts of ethyl acetate, and 21 parts of isopropyl alcohol (hereinafter also abbreviated as IPA) were mixed, and the obtained solution of the terminal isocyanate prepolymer was gradually added thereto at room temperature. Then, the mixture was reacted at 50 °C for 1 hour to obtain a polyester-based urethane resin B1 solution having a solid content of 30%, a mass average molecular weight of 70,000, and an amine value of 4 mg KOH / g. The molecular weight distribution is shown in Table 2.

[0129] [Synthesis Examples 2-2 to 2-5] (Synthesis of Polyester-based Urethane Resins B2 to B5) Polyester-based urethane resin B2 to B5 solutions were obtained in the same manner as in Synthesis Example 2-1 except that the raw materials and charging ratios described in Table 2 were used. The molecular weight distributions are shown in the same table. The abbreviations described in the table represent the following. IBPA: Iminobispropylamine

[0130] [Table 2]

[0131] In the ink adjustment example, the following were used. · Polyvinyl butyral resin solution: A polyvinyl butyral resin having vinyl alcohol units, vinyl acetate units, and vinyl butyral units and containing 73% by mass of butyral cyclic groups (glass transition point 70 °C, weight average molecular weight 50,000, chlorine content 0% by mass, nitration degree 0% by mass), a 30% by mass solid content solution in a mixed solvent of ethyl acetate / isopropanol = 1 / 1 · Vinyl chloride-vinyl acetate copolymer resin solution: A 30% solids ethyl acetate solution of vinyl chloride-vinyl acetate copolymer resin (Solvaine TA3 manufactured by Nissin Chemical Co., chlorine content 47.1% by mass, nitrification degree 0% by mass). · Cellulose resin solution: DLX5-8: Nitrocellulose manufactured by ICI Novel enterprises, weight average molecular weight 50,000, nitrogen content 12.0%, glass transition temperature 150 °C (30% solids isopropanol solution). · Rosin resin solution: Harester P, a rosin-modified pentaerythritol ester manufactured by Harima Kasei Co., 30% solids ethyl acetate solution. · Acrylic resin solution: BR-105, an acrylic resin manufactured by Mitsubishi Chemical Co., weight average molecular weight 60,000, glass transition point 50 °C, acid value 3.5 mgKOH / g, 30% solids ethyl acetate solution. · C.I. Pigment Yellow 14: Manufactured by Toyo Color Co., Ltd. (chlorine content 10.8% by mass, nitrification degree 0% by mass).

[0132] [Ink Preparation Example 3-1] (Preparation of Ink C1) 5 parts of C.I. Pigment Blue 15:3 (manufactured by Toyo Color Co., product name: LIONOL BLUE FG-7330, chlorine content 0% by mass, nitrification degree 0% by mass), 10 parts of polyester-based urethane resin B1 solution, 15 parts of polyvinyl butyral resin (PVB) solution, 10 parts of a mixed solvent (propyl acetate / IPA = 70 / 30 (mass ratio)) were stirred and mixed, and after kneading with a sand mill, 30 parts of polyester-based urethane resin (B) and 30 parts of a mixed solvent (normal propyl acetate / isopropyl alcohol = 70 / 30 (mass ratio)) were stirred and mixed to obtain Ink C1.

[0133] [Ink Preparation Examples 3-2 to 3-11] (Preparation of Inks C2 to C11) Inks C2 to C11 were obtained in the same manner as in Preparation Example 3-1, except that the raw materials and charging ratios shown in Table 3 were used.

[0134]

Table 3

[0135] [Synthesis Example of Isocyanate Curing Agent] (Isocyanate Curing Agent F1) In a reaction vessel with a stirring blade under a nitrogen gas atmosphere, 15 parts of trimethylolpropane, 60.3 parts of toluene-2,4-diisocyanate, and 32.3 parts of ethyl acetate that had been dehydrated in advance were reacted at 50 °C and a stirring speed of 150 rpm for 3 hours to obtain isocyanate curing agent F1. F1 had a weight average molecular weight of 1200, Mw / Mn of 2.5, and a solid content of 70 mass%.

[0136] In the examples described below, in addition to the above isocyanate curing agent F1, the following F2 was also used. (Isocyanate Curing Agent F2) ·E402-80B, manufactured by Asahi Kasei Corporation Weight average molecular weight: 4100 Mw / Mn: 3.4 Solid content 70 mass%

[0137] [Adhesive Synthesis Example 4-1] (Synthesis of Polyol Compound D1) Into a reaction vessel equipped with a stirrer, thermometer, reflux condenser, dropping funnel, and nitrogen gas inlet tube, 40 parts of a bifunctional polypropylene glycol with a number average molecular weight of about 2,000, 30 parts of a bifunctional polypropylene glycol with a number average molecular weight of about 400, 10 parts of a trifunctional polypropylene glycol with a number average molecular weight of about 400, 20 parts of a bifunctional polyether polyol ECOPROL 2000 with a number average molecular weight of about 2000, and 26 parts of tolylene diisocyanate were charged into the reaction vessel. While stirring under a nitrogen gas stream, it was heated at 80 to 90 °C for 5 hours to carry out a urethanization reaction. During the urethanization reaction, 0.1% of dibutyltin dilaurate (DBTDL) was added as a reaction catalyst to promote the reaction, and a polyether urethane polyol was obtained. 0.02 part of phosphoric acid was added to the obtained polyether urethane polyol, and it was adjusted to a solid content concentration of 75% with ethyl acetate to obtain a polyol compound D1 solution. The weight average molecular weight of the polyol compound D1 was 36000, and the molecular weight distribution (Mw / Mn) was 3.5.

[0138] [Adhesive Synthesis Example 4-2] (Synthesis of Polyol Compound D2) Into a reaction vessel equipped with a stirrer, a thermometer, a reflux condenser, a dropping funnel, and a nitrogen gas inlet tube, 10 parts of a bifunctional polypropylene glycol having a number average molecular weight of about 2,000, 90 parts of a bifunctional polypropylene glycol having a number average molecular weight of about 400, and 35 parts of tolylene diisocyanate were charged into the reaction vessel, and heated at 80 to 90 °C for 5 hours with stirring under a nitrogen gas stream to carry out a urethanization reaction. During the urethanization reaction, 0.1% of dibutyltin dilaurate (DBTDL) was added as a reaction catalyst to promote the reaction, and a polyether urethane polyol was obtained. To the obtained polyether urethane polyol, 0.01 part of phosphoric acid and 0.02 part of DYNASYLAN GLYMO were added, and adjusted to a solid content concentration of 75% with ethyl acetate to obtain a polyol compound D2 solution. The weight average molecular weight of the polyol compound D2 was 25,000, and the molecular weight distribution (Mw / Mn) was 1.9.

[0139] [Adhesive Synthesis Example 4-3] (Synthesis of Polyol Compound D3) Into a reaction vessel equipped with a stirrer, a thermometer, a reflux condenser, a dropping funnel, and a nitrogen gas inlet tube, 15 parts of a bifunctional polypropylene glycol having a number average molecular weight of about 2,000, 70 parts of a bifunctional polypropylene glycol having a number average molecular weight of about 400, 15 parts of a trifunctional polypropylene glycol having a number average molecular weight of about 400, and 35 parts of tolylene diisocyanate were charged into the reaction vessel, and heated at 80 to 90 °C for 5 hours with stirring under a nitrogen gas stream to carry out a urethanization reaction. During the urethanization reaction, 0.2% of Organic TC-100 was added as a reaction catalyst to promote the reaction, and a polyether urethane polyol was obtained. To the obtained polyether urethane polyol, 0.01 part of phosphoric acid and 0.02 part of DYNASYLAN GLYMO were added, and adjusted to a solid content concentration of 75% with ethyl acetate to obtain a polyol compound D3 solution. The weight average molecular weight of the polyol compound D3 was 58,000, and the molecular weight distribution (Mw / Mn) was 6.2.

[0140] [Adhesive Comparative Synthesis Example 4-1] (Synthesis of Polyol Compound E1) Into a reaction vessel equipped with a stirrer, a thermometer, a reflux condenser, a dropping funnel, and a nitrogen gas inlet tube, 15 parts of a bifunctional polypropylene glycol with a number average molecular weight of about 2,000, 65 parts of a bifunctional polypropylene glycol with a number average molecular weight of about 400, 20 parts of a trifunctional polypropylene glycol with a number average molecular weight of about 400, and 36 parts of tolylene diisocyanate were charged. While stirring under a nitrogen gas stream, the mixture was heated at 80 - 90 °C for 5 hours to carry out a urethanization reaction. During the urethanization reaction, 0.2% of Organic TC-100 was added as a reaction catalyst to promote the reaction, and a polyether urethane polyol was obtained. To the obtained polyether urethane polyol, 0.01 part of phosphoric acid and 0.02 part of DYNASYLAN GLYMO were added, and the solid content concentration was adjusted to 75% with ethyl acetate to obtain a polyol compound E1 solution. The weight average molecular weight of the polyol compound E1 was 80,000, and the molecular weight distribution (Mw / Mn) was 10.2.

[0141]

Table 4

[0142] [Adhesive Synthesis Example 5-1] (Synthesis of Polyol Compound D4) Into a reaction vessel equipped with a stirrer, a thermometer, a reflux condenser, a dropping funnel, and a nitrogen gas inlet tube, 20 parts of 1,6-hexanediol (1,6HG), 20 parts of neopentyl glycol (NPG), 30 parts of isophthalic acid, and 30 parts of sebacic acid were charged, and an esterification reaction was carried out at 240 °C. After a predetermined amount of water was distilled off, the pressure was gradually reduced, and a deglycolization reaction was carried out at 250 °C under 1 mmHg or less for 5 hours to obtain a polyester polyol. Then, 1 part of isophorone diisocyanate was added, and the reaction was carried out at 150 °C for 2 hours to obtain a polyester polyurethane polyol. To this polyester polyol, 1 part of trimellitic anhydride (TMA) was added, and the reaction was carried out at 180 °C for 2 hours. Then, 0.2 part of DYNASYLAN GLYMO was added, and it was diluted with ethyl acetate to a non-volatile content of 60% to obtain a polyol compound D4 solution. The weight average molecular weight of the polyol compound D4 was 26,000, and the molecular weight distribution (Mw / Mn) was 2.8.

[0143] [Adhesive Synthesis Example 5-2] (Synthesis of Polyol Compound D5) Into a reaction vessel equipped with a stirrer, thermometer, reflux condenser, dropping funnel, and nitrogen gas inlet tube, 15 parts of ethylene glycol (EG), 10 parts of 1,6-hexanediol, 20 parts of neopentyl glycol, 0.5 part of trimethylolpropane (TMP), 32 parts of isophthalic acid, and 20 parts of succinic acid were charged, and an esterification reaction was carried out at 240°C. After a predetermined amount of water had distilled off, the pressure was gradually reduced, and a deglycolization reaction was carried out at 250°C under 1 mmHg or less for 4.5 hours to obtain a polyester polyol. Thereafter, 2 parts of isophorone diisocyanate were added, and the reaction was carried out at 150°C for 2 hours to obtain a polyester polyurethane polyol. 1 part of trimellitic anhydride was added to this polyester polyol, and the reaction was carried out at 180°C for 2 hours. Thereafter, 0.2 part of DYNASYLAN GLYMO was added, and then it was diluted with ethyl acetate to a nonvolatile content of 60% to obtain a solution of polyol compound D5. The weight average molecular weight of polyol compound D5 was 24,000, and the molecular weight distribution (Mw / Mn) was 4.2.

[0144] [Adhesive Synthesis Example 5-3] (Synthesis of Polyol Compound D6) Into a reaction vessel equipped with a stirrer, thermometer, reflux condenser, dropping funnel, and nitrogen gas inlet tube, 20 parts of 1,6-hexanediol, 20 parts of neopentyl glycol, 30 parts of isophthalic acid, and 30 parts of sebacic acid were charged, and an esterification reaction was carried out at 240°C. After a predetermined amount of water had distilled off, the pressure was gradually reduced, and a deglycolization reaction was carried out at 250°C under 1 mmHg or less for 5 hours to obtain a polyester polyol. Thereafter, 1 part of tolylene diisocyanate was added, and the reaction was carried out at 150°C for 2 hours to obtain a polyester polyurethane polyol. 1 part of trimellitic anhydride was added to this polyester polyol, and the reaction was carried out at 180°C for 2 hours. 0.2 part of DYNASYLAN GLYMO was added to this polyester polyurethane polyol, and then it was diluted with ethyl acetate to a nonvolatile content of 60% to obtain a solution of polyol compound D6. The weight average molecular weight of polyol compound D6 was 26,000, and the molecular weight distribution (Mw / Mn) was 2.2.

[0145] [Adhesive Synthesis Example 5-4] (Synthesis of Polyol Compound D7) Into a reaction vessel equipped with a stirrer, thermometer, reflux condenser, dropping funnel, and nitrogen gas inlet tube, 20 parts of ethylene glycol, 30 parts of diethylene glycol (DEG), 35 parts of isophthalic acid, and 15 parts of sebacic acid were charged, and an esterification reaction was carried out at 240 °C. After distilling off a predetermined amount of water, the pressure was gradually reduced, and a deglycolization reaction was carried out at 250 °C for 5 hours under a pressure of 1 mmHg or less to obtain a polyester polyol. To this polyester polyol, 0.5 part of DYNASYLAN AMEO was added, and then it was diluted with ethyl acetate to a nonvolatile content of 60% to obtain a solution of polyol compound D7. The weight average molecular weight of polyol compound D7 was 22,000, and the molecular weight distribution (Mw / Mn) was 1.9.

[0146] [Table 5]

[0147] [Isocyanate Compound] (Isocyanate Compound I1) 23 parts of a bifunctional polypropylene glycol with a number average molecular weight of about 2,000, 18 parts of a bifunctional polypropylene glycol with a number average molecular weight of about 400, 2 parts of a trifunctional polypropylene glycol with a number average molecular weight of about 400, and 30 parts of 4,4'-diphenylmethane diisocyanate were charged into a reaction vessel, and heated at 70 - 80 °C for 7 hours with stirring under a nitrogen gas stream to carry out a urethanization reaction. After completion of the reaction, 7 parts of a trimethylolpropane adduct of tolylene diisocyanate were mixed. It was diluted with ethyl acetate to a solid content concentration of 75% to obtain a solution of a polyisocyanate containing a polyether urethane polyisocyanate. 80 parts of the above polyisocyanate solution and 20 parts of Desmodur L75 (manufactured by Sumika Covestro Urethane Co., Ltd., trimethylolpropane adduct of toluene diisocyanate, NCO group content 13%, solid content concentration 75%) were mixed to obtain an isocyanate compound I1 solution.

[0148] (Isocyanate Compound I2) A solution of hexamethylene diisocyanate biuret with a nonvolatile content of 95% by mass (ethyl acetate) was used as the isocyanate compound I2 solution.

[0149] [Example 1] (Production of packaging material G1) In a propyl acetate / IPA mixed solvent (mass ratio 70 / 30), Ink C1 was diluted and adjusted so that the viscosity in a Zahn cup #3 (manufactured by a separate company) was 15 seconds (at 25°C), and it was printed on the corona-treated surface of a one-sided corona-treated polypropylene film using a gravure printing machine equipped with a gravure plate with a plate depth of 35 μm and dried at 50°C to obtain a printed product (OPP). The coating amount after drying of the printed layer was 2.5 g / m 2 was obtained. On the printed layer of the above printed product, a solution prepared by adding 1 part of a polyol compound D1 solution, 1 part of an isocyanate compound F3 solution, and ethyl acetate to adjust the nonvolatile content to 30% was applied using a gravure roll coater, dried for the solvent in an oven, and 2.5 g / m 2 of an adhesive layer was formed, and it was laminated with an unstretched polypropylene (CPP) film (thickness 30 μm, surface corona discharge treatment) using a laminator and kept warm at 40°C for 3 days to produce packaging material G1. Composition: Biaxially stretched polypropylene (OPP) film (thickness 20 μm) / printed layer / adhesive layer / unstretched polypropylene (CPP) film (thickness 30 μm, surface corona discharge treatment)

[0150] In the following examples and comparative examples, the following were used. NY: Biaxially stretched nylon film with surface corona discharge treatment (thickness 15 μm) LLDPE 30 μm: Linearly low-density polyethylene film with surface corona discharge treatment (thickness 30 μm) LLDPE 150 μm: Linearly low-density polyethylene film with surface corona discharge treatment (thickness 150 μm)

[0151] [Examples 2 to 21] (Production of packaging materials G2 to 21) In the same manner as in Example 1, packaging materials G2 to 21 were obtained according to the compositions in Table 6, respectively. In Examples 18 and 19, after adjusting the viscosity of the ink with a propyl acetate / IPA mixed solvent (mass ratio 70 / 30), 3 parts each of isocyanate-based curing agents F1 and F2 were added to 100 parts of the ink.

[0152] [Comparative Examples 1 to 3] (Preparation of Packaging Materials H1 to 3) In the same manner as in Example 1, packaging materials H1 to 3 were obtained according to the compositions in Table 6.

[0153] The following property evaluations were performed using the above packaging materials. The results are shown in Table 6.

[0154] (Lamination Strength) For the packaging materials obtained in the above Examples and Comparative Examples, samples were cut out to a length of 150 mm and a width of 15 mm, opened at the ink / OPP film or ink / NY film interface, and the lamination strength in the 90° direction was measured using a tensile tester. [Evaluation Criteria] A (Excellent): 1.5 N / 15 mm or more B (Good): 1.0 N / 15 mm or more and less than 1.5 N / 15 mm C (Passable): 0.8 N / 15 mm or more and less than 1.0 N / 15 mm D (Unacceptable): 0.5 N / 15 mm or more and less than 0.8 N / 15 mm E (Poor): Less than 0.5 N / 15 mm Note that the evaluations for practical usability are A to C.

[0155] (Ease of Tearing) For the packaging materials obtained in the above Examples and Comparative Examples, samples were prepared according to JIS K7128-1:1998 and evaluated by the resistance when torn with a Toyo Seiki 201 universal tensile tester. [Evaluation Criteria] A (Excellent): Less than 0.5 N B (Good): 0.5 N or more and less than 1.0 N C (Passable): 1.0 N or more and less than 1.5 N D (Unacceptable): 1.5 N or more and less than 2.0 N E (Poor): 2.0 N or more Note that the evaluations for practical usability are A to C.

[0156] (Recyclability evaluation) The packaging materials obtained in the above Examples and Comparative Examples were cut into a size of 4 cm × 4 cm, washed with water and dried. The pieces of packaging material were put into a single-screw extruder, melted and kneaded at a screw rotation speed of 250 rpm and 220 °C, and a 150-mesh filter was used to extrude from the discharge part of the extrusion device at a pressure of 4 MPa. Then, it was immediately cut with a pelletizer and immersed in cold water for cooling. In this way, pellets of recycled plastic recycled from the packaging material were obtained. Then, the pellets of recycled plastic were each extruded at 220 °C using a T-die extruder to produce a film-shaped molded body with a thickness of 50 μm. Regarding the obtained film, at 0.5 m 2 The number of foreign matters and foams distinguishable by visual inspection per square meter was counted and evaluated according to the following criteria. [Evaluation criteria] A (Excellent): The number of foreign matters and foams is less than 40 B (Good): The number of foreign matters and foams is 40 or more and less than 80 C (Passable): The number of foreign matters and foams is 80 or more and less than 120 D (Unacceptable): The number of foreign matters and foams is 120 or more and less than 200 E (Poor): The number of foreign matters and foams is 200 or more. The evaluations of being practically applicable are A to C.

[0157] [Table 6]

[0158] [Table 6]

Claims

1. A packaging material having a base material, a printing layer, an adhesive layer, and a sealant, containing 80% by mass or more of a polyolefin resin in the total mass of the packaging material, wherein the printing layer contains a pigment and a binder resin, and the binder resin contains a polyester-based urethane resin (B) and a polyvinyl acetal resin, wherein the molecular weight distribution (Mw / Mn) of the polyester-based urethane resin (B) is 2.0 to 8.0, wherein the adhesive layer is composed of a cured product of a reactive adhesive containing a polyol compound (D) and an isocyanate compound (I), and the molecular weight distribution (Mw / Mn) of the polyol compound (D) is 1.5 to 10.0 (however, at least a packaging material having a configuration in which a first base material, a printing layer, a polyurethane-based adhesive layer, and a second base material are laminated in this order from the outer layer side, and the polyurethane-based adhesive layer is provided in contact with the second base material, and the polyurethane-based adhesive layer is used to remove the second base material).

2. The packaging material according to claim 1, wherein the reactive adhesive contains phosphoric acid and / or a phosphoric acid derivative.

3. The packaging material according to claim 1, wherein the reactive adhesive contains a silane coupling agent.

4. The packaging material according to any one of claims 1 to 3, wherein the polyol compound (D) contains structural units derived from polyester polyol and / or polyether polyol, and structural units derived from an acid anhydride.

5. The packaging material according to any one of claims 1 to 4, wherein the polyol compound (D) contains structural units derived from polyether polyol, and the molecular weight distribution (Mw / Mn) of the polyol compound (D) is 3.0 to 10.

0.

6. The packaging material according to any one of claims 1 to 4, wherein the polyol compound (D) contains structural units derived from polyester polyol, and the molecular weight distribution (Mw / Mn) of the polyol compound (D) is 1.5 to 5.

0.

7. The packaging material according to any one of claims 1 to 6, wherein the chlorine content of the binder resin is 5% by mass or less.

8. The packaging material according to claim 1, wherein the polyester-based urethane resin (B) contains structural units derived from a polyester that is a condensate of a dibasic acid and a diol, and the dibasic acid contains sebacic acid and / or succinic acid.

9. The packaging material according to claim 8, wherein the diol contains a branched diol and a linear diol.

10. The packaging material according to any one of claims 1 to 9, wherein the content of the pigment is 30% by mass or less in the total mass of the printing layer.

11. The packaging material according to any one of claims 1 to 10, wherein the printing layer further contains an isocyanate-based curing agent having a weight average molecular weight of 800 to 8000.

12. The packaging material according to any one of claims 1 to 11, wherein the base material and the sealant contain a polyolefin resin.

13. The packaging material according to claim 12, wherein the polyolefin resin is a polypropylene-based resin.

14. The packaging material according to any one of claims 1 to 13, wherein the chlorine content is 0.4% by mass or less in the total mass of the packaging material.

15. A method for manufacturing a packaging material having a base material, a printing layer, an adhesive layer, and a sealant, and containing 80% by mass or more of an olefin resin in the total mass (however, at least a first base material, a printing layer, a polyurethane-based adhesive layer, and a second base material are laminated in this order from the outer layer side, and the polyurethane-based adhesive layer is provided in contact with the second base material, and the packaging material used to separate the second base material is excluded), including a step of printing a gravure ink containing a polyester-based urethane resin (B) and a polyvinyl acetal resin on the base material to form the printing layer, and a step of applying a reactive adhesive containing a polyol compound (D) and an isocyanate compound (I) to form the adhesive layer, wherein the molecular weight distribution (Mw / Mn) of the polyester-based urethane resin (B) is 2.0 to 8.0, The method for manufacturing a packaging material, wherein the molecular weight distribution (Mw / Mn) of the polyol compound (D) is 1.5 to 10.0.

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