Packing material and method of manufacturing the same

Abstract

To provide a packing material that has superior laminate strength, easy-to-tear properties and superior recyclability.SOLUTION: There is provided a packing material that has a base material, a print layer, an adhesive layer, and a sealant. The packing material contains 80 mass% or more of polyolefin resin for the total mass of the packing material. The print layer includes pigment and binder resin, the adhesive layer is made of a cured body of a reactive adhesive including 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 producing the same. [Background technology]

[0002] In recent years, there has been an increasing demand for packaging materials to be recycled not only for their traditional functions such as lamination strength and tearability, but also from the perspective of environmental friendliness and effective use of resources. For example, since multi-layer packaging materials that contain multiple different materials are difficult to separate and sort, mono-material packaging materials that are suitable for material recycling are being considered (Patent Document 1).

[0003] Generally, packaging materials are provided with patterns such as pictures, and a printed layer made of ink is provided to make the contents invisible. An adhesive layer and a thermoplastic substrate are further laminated on the printed layer in order to form a laminate for packaging materials. The laminate is then heat-sealed to form a packaging bag by heat-sealing the thermoplastic substrates of the outermost layers. Such packaging bags are often used in the food packaging field, and if the adhesion between the layers is low, peeling occurs between the layers during filling or transportation of the contents, resulting in problems such as a decrease in design and leakage of the contents, so that laminates in the food packaging field are required to have good adhesion strength.

[0004] In addition, in the case of food packaging bags, the packaging bag is often directly torn by hand to open it in order to take out the contents. In this case, if the packaging bag has poor tearability, problems such as excessive force being applied or the bag being torn in an unexpected direction causing the contents to spill out occur, so good tearability is required.

[0005] For example, Patent Document 2 describes a technology in which an isocyanate-based curing agent is used in an ink containing a polyurethane resin to increase laminate strength and thereby exhibit easy tearability. Patent Document 3 describes a technology in which a silane coupling agent is used in addition to an isocyanate-based curing agent. However, both of these relate to packaging materials composed of different substrates, and there remain issues in terms of recyclability. For these reasons, no technology has been disclosed to date that combines recyclability with physical properties suitable for packaging materials, such as laminate strength and easy tearability. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2021-160258 A [Patent Document 2] JP 2017-031298 A [Patent Document 3] JP 2019-199509 A Summary of the Invention [Problem to be solved by the invention]

[0007] An object of the present invention is to provide a packaging material which has excellent lamination strength, easy tearability, and excellent recyclability. [Means for solving the problem]

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

[0009] That is, the present invention provides a packaging material having a substrate, a printing layer, an adhesive layer, and a sealant, the packaging material containing a polyolefin resin in an amount of 80% by mass or more based on the total mass of the packaging material, the printing layer contains a pigment and a binder resin, The packaging material relates to the above-mentioned adhesive layer, which is made 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 above-mentioned polyol compound (D) is 1.5 to 10.0.

[0010] The present invention also relates to the above packaging material, wherein the polyol compound (D) contains a structural unit 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 a constituent unit 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 binder resin has a chlorine content of 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 that 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 comprises 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 based on the total mass of the printed layer.

[0018] The present invention also relates to the above packaging material, wherein the printed layer further contains an isocyanate-based curing agent having a weight average molecular weight of 800 to 8,000.

[0019] The present invention also relates to the above packaging material, wherein the substrate 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 mass % or less based on the total mass of the packaging material.

[0022] The present invention also provides a method for producing a packaging material having a substrate, a printing layer, an adhesive layer, and a sealant, and containing an olefin resin in an amount of 80% by mass or more based on the total mass of the packaging material, comprising the steps of: The method includes the steps of printing a gravure ink containing a polyester-based urethane resin (B) on a substrate to form a printed layer, and then printing a reaction mixture containing a polyol compound (D) and an isocyanate compound (I) on the substrate to form a printed layer. The method includes applying a reactive adhesive to form an adhesive layer, The polyol compound (D) has a molecular weight distribution (Mw / Mn) of 1.5 to 10.0. Effect of the Invention

[0023] The present invention makes it possible to provide a packaging material that has excellent laminate strength, easy tearability, and excellent recyclability. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] The following describes in detail the embodiments of the present invention. However, the description of the components described below is one example (representative example) of the embodiment of the present invention, and the present invention is not limited to these contents as long as it does not go beyond the gist of the present invention.

[0025] In the present invention, "gravure ink" is one embodiment of ink. In addition, ink consisting of a mixture of "gravure ink" and "isocyanate-based curing agent" is also "gravure ink". The ink constituting the printing layer may be "gravure ink" or any other ink form. The printing layer formed by printing may be simply referred to as "ink layer", but this has the same meaning.

[0026] In the following description, the polyester-based urethane resin (B) used as the binder resin of the printed layer refers to a urethane resin containing structural units derived from polyester, preferably an embodiment of a urethane resin further having a urea bond. On the other hand, polyester polyol, polyether polyol, and other polyols used in reactive adhesives are in the form of having hydroxyl groups at multiple ends. The polyol compound (D) is preferably in the form of having a urethane bond, and preferably in the form of having no urea bond. In addition, even a very small amount of urea bond unintentionally formed due to the inclusion of moisture during the production of the polyol compound (D) is not excluded.

[0027] The packaging material of the present invention will be described in detail below. The present invention relates to a packaging material having a substrate, a printing layer, an adhesive layer, and a sealant, The packaging material contains 80% or more by mass of polyolefin resin, the printing layer contains a pigment and a binder resin, The packaging material, wherein the adhesive layer is made 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 including 80% by mass or more of polyolefin resin in the total mass of the packaging material, it is possible to obtain a molding material that exhibits recyclability, has good moldability after recycling, and can be used for various applications. In addition, by using an adhesive containing a polyol compound (D) with a molecular weight distribution (Mw / Mn) of 1.5 to 10.0, the leveling property during adhesive application and the adhesion between each layer are improved, and easy tearing properties can be imparted to the packaging material. Easy tearing properties contribute to improving recyclability not only in terms of convenience, which makes it easier to open 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 substrate, a printing layer, an adhesive layer, and a sealant are laminated. Specific examples of the structure include, but are not limited to, the following structures. In the structure descriptions (1) to (3) below, " / " indicates the boundary between layers. Specific examples of the laminate structure include, starting from the outer layer side (left side), the following laminate structures: (1) Substrate / printed layer / adhesive layer / sealant (2) Substrate / printed layer / adhesive layer / intermediate substrate / adhesive layer / sealant (3) Substrate / printed layer / adhesive layer / first intermediate substrate / adhesive layer / second intermediate substrate / adhesive layer / sealant

[0029] The packaging material contains a polyolefin resin in an amount of 80% by mass or more based on the total mass of the packaging material. The content is more preferably 85% by mass or more, and even more preferably 90% by mass or more. By containing the polyolefin resin in the above range, a molding material can be obtained that has a high degree of ease in the separation process, a high degree of recyclability, good moldability, and can be used for various applications. From the viewpoint of recyclability and easy tearing, the substrate, the sealant, and the intermediate substrate used as needed are preferably made of the same material. The substrate, the sealant, and the intermediate substrate used as needed preferably contain a polyolefin resin. Furthermore, of the total mass of the substrate and sealant, and the intermediate substrate used as needed, the polyolefin resin preferably accounts for 50 mass% or more, more preferably 60 mass% or more, even more preferably 70 mass% or more, even more preferably 80 mass% or more, and particularly preferably 90 mass% or more. Moreover, the polyolefin resin is more preferably a polypropylene-based resin and / or a polyethylene-based resin, further preferably a polypropylene-based resin, and particularly preferably a polypropylene-based resin that is a copolymer with ethylene and / or butene.

[0030] <Chlorine content in packaging materials> Due to halogen elements that may be contained in the packaging material, halogen gas or hydrogen chloride, an acidic gas, may be generated during pellet production, which may damage equipment or endanger human health. Furthermore, if bubbles are generated during pellet production, when the produced pellets are used to produce a molded product, the surface is likely to become uneven, which may deteriorate the surface condition of the molded product. Therefore, the chlorine content in the packaging material is preferably 0.4 mass% or less, more preferably 0.2 mass% or less, even more preferably 0.1 mass% or less, and particularly preferably 0.05 mass% or less, based on the total mass of the packaging material.

[0031] (Method for measuring chlorine content in packaging materials) The chlorine content of the packaging material can be measured by known methods such as ion chromatography (IC) and ICP mass spectrometry (ICP-MS). Specifically, it can be determined by the same method as the analytical method for the chlorine content described below.

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

[0033] The substrate containing polyolefin resin is simply a substrate made of polyolefin resin. The substrate may be laminated, or a substrate 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" may be a film having properties different from the substrate made of polyolefin resin, and may be of any type. In addition, in the case of a laminated substrate, it may be in a form including an adhesive layer. The method of laminating the substrate is not particularly limited, and may be a conventionally known method such as coextrusion, heat fusion, or pressure bonding via an adhesive layer.

[0034] The substrate made of the polyolefin resin has higher resistance to alkaline aqueous solutions and heat during the molding process than the ester substrate, and is less susceptible to thermal decomposition and hydrolysis, so that the molecular weight can be maintained high during recycling. Furthermore, from the viewpoint of ease of recovery after recycling, examples of the polyolefin substrate include polyethylene such as biaxially oriented polypropylene (OPP), non-oriented polypropylene (CPP), low density polyethylene (LDPE), linear low density polyethylene (LLDPE), medium density polyethylene (MDPE), high density polyethylene (HDPE), acid-modified polyethylene, acid-modified polypropylene, copolymer polypropylene, and films laminated with these. The thickness of the substrate is not particularly limited, and is preferably 5 μm or more and 150 μm or less, more preferably 10 μm or more and 70 μm or less, in consideration of processability into packaging containers. Among them, a film having heat sealability is preferably used, and CPP, heat sealable OPP, etc. correspond to them.

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

[0036] The substrate is preferably in a form containing additives such as antistatic agents, antifogging agents, and ultraviolet protection agents (coated or kneaded), in a form having an easily adhesive coating layer (e.g., a layer containing polyvinyl alcohol and its derivatives), in a form in which the surface of the substrate is corona-treated or low-temperature plasma-treated, etc. The above-mentioned additions 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 suitably 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] <Print layer> The printed layer in the packaging material is a layer that displays any design, pattern, character, symbol, etc. for the purpose of providing decoration or aesthetics; displaying the contents, expiration date, and manufacturer or seller, and is not particularly limited. The printed layer may be a solid printed layer. The method for forming the printed layer is not particularly limited, and the printed layer is formed using a printing ink containing a pigment and a binder resin. The printed layer may be a single layer or a multi-layer structure, and may be formed on the surface layer. The thickness of the printed 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] (Pigments) The printed layer in the packaging material preferably contains a pigment and is formed using a printing ink containing the pigment. In consideration of quality deterioration due to coloring after recycling, the content of the colorant containing the pigment is preferably 30% by mass or less, more preferably 25% by mass or less, and even more preferably 23% by mass or less, based on the total mass of the printed layer. The pigment may be any of organic pigments, inorganic pigments, and extender pigments, but inorganic pigments containing titanium oxide are preferred, and extender pigments such as silica, barium sulfate, kaolin, clay, calcium carbonate, and magnesium carbonate are preferred. Organic pigments made of organic compounds and organometallic complexes are preferred. Colorants such as pigments may be used alone or in combination. Any pigment with a CI pigment number may be used.

[0039] [Organic pigments] Examples of the organic pigment include, but are not limited to, soluble azo pigments, insoluble azo pigments, azo pigments, phthalocyanine pigments, halogenated phthalocyanine pigments, anthraquinone pigments, anthanthrone pigments, dianthraquinonyl pigments, anthrapyrimidine pigments, perylene pigments, perinone pigments, quinacridone pigments, thioindigo pigments, dioxazine pigments, isoindolinone pigments, quinophthalone pigments, azomethine azo pigments, flavanthrone pigments, diketopyrrolopyrrole pigments, isoindoline pigments, indanthrone pigments, and carbon black pigments. Further examples include carmine 6B, lake red C, permanent red 2B, disazo yellow, pyrazolone orange, carmine FB, chromophthalic yellow, chromophthalic 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, and daylight fluorescent pigments.

[0040] The hue of the organic pigment is preferably at least one selected from the group consisting of black pigments, cyan pigments, green pigments, red pigments, purple pigments, yellow pigments, orange pigments, and brown pigments.More preferably, at least one selected from the group consisting of black pigments, cyan pigments, red pigments, and yellow pigments.Specific examples of organic pigments are shown by CI numbers of the Colour Index International (CI). Preferably CI Pigment Red 57:1, CI Pigment Red 48:1, CI Pigment Red 48:2, CI Pigment Red 48:3, CI Pigment Red 146, CI Pigment Red 242, CI Pigment Yellow 83, CI Pigment Yellow 14, CI Pigment Orange 38, CI Pigment Orange 13, CI Pigment Yellow 180, CI Pigment Yellow 139, CI Pigment Red 185, CI Pigment Red 122, CI Pigment Red 178 , CI Pigment Red 149, CI Pigment Red 144, CI Pigment Red 166, CI Pigment Violet 23, CI Pigment Violet 37, CI Pigment Blue 15, CI Pigment Blue 15:1, CI Pigment Blue 15:2, CI Pigment Blue 15:3, CI Pigment Blue 15:4, CI Pigment Blue 15:6, CI Pigment Green 7, CI Pigment Orange 34, CI Pigment Orange 64, CI Pigment Black 7.

[0041] [Inorganic pigments] Examples of inorganic pigments include titanium oxide, zinc oxide, zinc sulfide, barium sulfate, calcium carbonate, chromium oxide, silica, aluminum particles, mica, bronze powder, chrome vermilion, yellow lead, cadmium yellow, cadmium red, ultramarine, Prussian blue, red iron oxide, yellow iron oxide, iron black, titanium oxide, and zinc oxide. Aluminum can be either leafing or non-leafing type, with the non-leafing type being preferred.

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

[0043] The binder resin is preferably a thermoplastic resin soluble in an organic solvent. The binder resin is preferably a combination of a resin having a glass transition temperature of -60°C or more and less than 40°C and a resin having a glass transition temperature of 40°C or more and 200°C or less. More preferably, a combination of a resin having a glass transition temperature of -50°C or more and 0°C or less and a resin having a glass transition temperature of 50°C or more and 190°C or less is used. In this specification, the glass transition temperature means The values ​​are measured by a differential scanning calorimeter (DSC). The resin is mainly a urethane resin. The resin is preferably a polyvinyl acetal resin, a cellulose ester resin, a rosin resin, or the like, and more preferably a polyvinyl acetal resin.

[0044] Examples of binder resins 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 a mixture 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 structural units derived from polyester, preferably having a urea bond. It is preferable that the polyester-based urethane resin (B) contains polyester-derived structural units in a total mass of 40 mass% or more, more preferably 50 mass% or more, even more preferably 60 mass% or more, and particularly preferably 65 mass% or more. The polyester-based urethane resin (B) is not limited to the following, but may be, for example, a polyester-based urethane resin obtained by reacting a urethane prepolymer obtained by reacting a polyisocyanate with a polyol including a polyester polyol, and then reacting the urethane prepolymer with a polyamine (chain extender) and, if necessary, a reaction terminator. To obtain a urethane resin having a polyester-derived structural unit, for example, the above-mentioned urethane resin synthesis method may be used in which a polyester polyol is used as the polyol, but is not particularly limited thereto.

[0046] <Polyester polyol> The number average molecular weight of the polyester polyol is preferably 500 to 10,000, more preferably 1,000 to 5,000. Here, the number average molecular weight is calculated from the hydroxyl value, which is a value calculated by esterifying or acetylating the hydroxyl groups in the resin, back titrating the remaining acid with an alkali, converting the amount of hydroxyl groups in 1 g of the resin into mg of potassium hydroxide, and is measured according to JIS K0070. When the number average molecular weight of the polyester polyol is 10,000 or less, the printing layer has excellent blocking resistance against the plastic film. In addition, when the number average molecular weight of the polyester polyol is 500 or more, the flexibility of the printing layer is improved, and the adhesion to the plastic film is excellent.

[0047] The polyester polyol is preferably a polyester diol, and the polyester diol is preferably a polyester diol that is a condensation product of a diol and a dicarboxylic acid (also called a dibasic acid). The polyester polyol may be used alone or in combination of two or more kinds.

[0048] Suitable 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-cyclohexyldicarboxylic acid, dimer acid, and hydrogenated dimer acid. Among these, adipic acid, succinic acid, and sebacic acid are preferred. Furthermore, as a raw material for polyester polyol, Polyols and polyvalent carboxylic acids having three or more carboxyl groups can also be used in combination.

[0049] Suitable 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-monoglycerin ether, 2-monoglycerin ether, dimer diol, and hydrogenated dimer diol. Among these, polyester diol, which is a condensation product of a diol containing a branched diol and a dicarboxylic acid, is preferred. Furthermore, polyester diols obtained by ring-opening reaction of cyclic esters (lactones, etc.) may also be used.

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

[0051] Since the linear diol imparts crystallinity and the branched diol imparts flexibility, the polyurethane resin as a binder resin can provide a strong ink film and high lamination strength and easy tearability to the ink film by achieving a good balance between them. It is considered that the polyurethane resin containing a branched diol structure and / or a linear diol structure is effective in improving the efficiency of recycling packaging materials. As described below, 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 (hereinafter also referred to as MPD), neopentyl glycol (hereinafter 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, and the like. At least one branched diol selected from NPG and PG is particularly preferred.

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

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

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

[0056] Among these, preferred examples of polyester polyols include those containing adipic acid, succinic acid, sebacic acid or other dibasic acid, and both a branched diol and a linear diol, which improves the laminate strength of the packaging material.

[0057] Other polyols The polyol may include polyols other than polyester polyols. For example, polyether polyols, polycarbonate polyols, and polyolefin polyols can be used.

[0058] <Polyisocyanate> The polyisocyanate is preferably a diisocyanate, 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-trimethylsilyl diisocyanate, 1,3,4-trimethylsilyl diisocyanate, 1,4,5 ...4,5-trimethylsilyl diisocyanate, 1,4,5-trimethylsilyl diisocyanate, 1,4,5-trimethylsilyl diisocyanate, 1,4,5-trimethylsilyl diisocyanate, 1,4,5-trimethylsilyl diisocyanate, Representative examples include methylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, cyclohexane-1,4-diisocyanate, xylylene diisocyanate, isophorone diisocyanate, lysine diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, 1,3-bis(isocyanatemethyl)cyclohexane, methylcyclohexane diisocyanate, m-tetramethylxylylene diisocyanate, and dimer diisocyanate in which the carboxyl group of a dimer acid is converted to an isocyanate group. These can be used alone or in a mixture of two or more kinds. Among them, isophorone diisocyanate, tolylene diisocyanate, and 4,4'-diphenylmethane diisocyanate are preferred, and isophorone diisocyanate is more preferred from the viewpoint of solubility.

[0059] Chain extender The chain extender is preferably a polyamine. The polyamine is preferably an organic diamine, and includes, but is 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-hydroxyethylpropylenediamine, 2-hydroxypropylethylenediamine, di-2-hydroxypropylethylenediamine, etc., can also be used. These organic diamines can be used alone or in a mixture of two or more, but isophoronediamine is preferred. In addition, diethylenetriamine, iminobispropylamine: (IBPA, 3,3'-diaminodipropylamine), N-(3-aminopropyl)butane-1,4-diamine: (spermidine), 6,6-iminodihexylamine, 3,7-di Polyfunctional amines having three or more amino groups, such as azanonane-1,9-diamine and N,N'-bis(3-aminopropyl)ethylenediamine, can also be used in combination with the above organic diamines.

[0060] <Reaction stopper> In the case of a urethane resin that can be produced only by the urethanization step, it is preferable to use a monoalcohol or a monoamine as the reaction terminator, and in the case of a urethane resin that is produced by carrying out a urethanization reaction step in addition to the urethanization step, it is preferable to use a monoamine. The monoalcohol is preferably a substituted or unsubstituted alcohol, and suitable examples thereof include methanol, ethanol, n-propanol, isopropyl alcohol, 1-butanol, etc. The monoamine is preferably a substituted or unsubstituted monoamine, and suitable examples thereof include n-butylamine, n-dibutylamine, octylamine, diethylamine, monoethanolamine, monopropanolamine, diethanolamine, dipropanolamine, etc. In addition, the compounds listed as the chain extenders can also be used as the reaction terminator, and at least one of them may be used, or two or more of them may be used in combination.

[0061] In the above-mentioned production of a urethane prepolymer having an isocyanate group at its terminal obtained by reacting a polyisocyanate with a 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 1.3 to 3, and more preferably 1.5 to 2.

[0062] The polyester-based urethane resin (B) and other urethane resins preferably have active hydrogen groups such as hydroxyl groups and / or amino groups. When the resin has a hydroxyl group, the hydroxyl value is preferably 0.5 to 30 mgKOH / g, more preferably 1 to 20 mgKOH / g, and even more preferably 2 to 15 mgKOH / g. When the resin has an amino group, the amine value is preferably 0.1 to 15 mgKOH / g, and even more 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 even more 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 20,000 to 100,000, more preferably 25,000 to 90,000, and even more preferably 30,000 to 80,000, in order to make the printed layer into a strong film by crosslinking with an isocyanate-based curing agent described later, and to 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). For example, Water2690 (manufactured by Waters) or HLC-8220 (manufactured by Tosoh Corporation) can be used as the GPC device, and PLgel, 5 μm, MIXED-D (manufactured by Polymer Laboratories), TSKgelSuperAW series (manufactured by Tosoh Corporation), TSKgelSuperH series (manufactured by Tosoh Corporation), etc. can be used as the column. Tetrahydrofuran, 1,2,4-trichlorobenzene, N,N-dimethylformamide (with 0.01N lithium bromide added), etc. can be used as the developing solvent, and the flow rate is preferably 0.5 to 1.5 milliliters / minute. An RI detector or the like can be used for detection, and the measurement can be performed under conditions such as a sample injection concentration of 0.5 to 1.5 milligrams / milliliter and an injection amount of 0.1 to 1.0 microliter. The weight average molecular weight can be determined as a polystyrene equivalent value.

[0064] The molecular weight distribution (Mw / Mn) of the polyester urethane resin (B) and other urethane resins is preferably 2.0 to 8.0, more preferably 2.5 to 7.0, and even more preferably 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 believed that the cohesive force and adhesive force are strengthened by crosslinking with the isocyanate curing agent described below, resulting in easy tearing. 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, the selection of urethane synthesis raw materials, the solid content mass ratio, the dripping speed of reactive raw materials such as polyisocyanate in the synthesis reaction, the stirring speed and the shape of the stirring blade, and the reaction temperature can be appropriately set in the synthesis of the urethane resin. In addition, when a chain extension reaction is performed, it is effective to set the dripping speed and temperature range control in a certain range when reacting polyamine with urethane prepolymer in order to make the molecular weight distribution fall within a predetermined range. Reaction temperature control is important, and it is preferable to control it between 50 and 130 ° C in the synthesis of urethane prepolymer, and it is preferable to control it to the range of 10 to 50 ° C when reacting polyamine with urethane prepolymer. In addition, setting the charging ratio of the reaction raw materials to an appropriate ratio is also effective in keeping the molecular weight distribution within a predetermined range. Examples of the charging ratio include the NCO / OH ratio, which is the ratio of the hydroxyl groups of the polyol and hydroxy acid, and the isocyanate groups of the polyisocyanate, and the amino group / NCO ratio, which is the ratio of the amino groups of the polyamine and the isocyanate groups of the urethane prepolymer. In order to control the molecular weight distribution, it is preferable to use a reaction terminator such as the above for the purpose of preventing excessive polymerization reaction.

[0066] [Resin L] When the binder resin contains a urethane resin, it is preferable that the binder resin 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 resin, cellulose-based resin, rosin-based resin, and acrylic resin. More preferably, it is a resin having a ring structure, even 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, and 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 substituent.

[0067] Resin L contains structural units having a ring structure in an amount of preferably 40 to 95 mass %, and more preferably 50 to 90 mass %, based on the mass of resin L. When the resin L contains a structural unit having a ring structure in the above range, the pigment dispersion in the printing ink is promoted. In addition, the laminate strength of the packaging material is excellent and deterioration over time can be suppressed. Furthermore, blocking resistance is excellent. 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 content of structural units derived from α-methylstyrene is 50% by mass and the content of structural units derived from butyl methacrylate, 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 according to the following formula. Formula: Content of structural units having a ring structure (% by mass) = Mass of monomer having ring structure × 100 / Total mass of all monomers constituting resin L

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

[0070] <Polyvinyl acetal resin> The polyvinyl acetal resin is an acetal cyclized product of reacting polyvinyl alcohol with an aldehyde such as butyraldehyde and / or formaldehyde, and preferably contains vinyl alcohol units, vinyl acetate units, and an acetal ring group. 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 is more preferably 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, and more preferably 10,000 to 80,000.The glass transition point of the polyvinyl acetal resin is preferably 50 to 80°C, and more preferably 60 to 75°C.

[0071] <Cellulose ester resin> The cellulose ester resin is preferably a cellulose acetate alkylate resin, and for example, cellulose acetate propionate and cellulose acetate butyrate are suitably used. The cellulose ester resin preferably has an alkyl group. The 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, or a hexyl group is 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 10,000, and further preferably 15,000 to 80,000. The glass transition point of the cellulose ester resin is preferably 120°C to 180°C, and more preferably 130 to 170°C. The combined use of urethane resin and cellulose ester resin improves printability, blocking resistance, and the like.

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

[0073] <Rosin ester> Rosin resin is an ester of low molecular weight polyol with a molecular weight of 1,000 or less and rosin acid. Rosin ester, which is a terephthalic acid condensation resin, is preferred. The low molecular weight polyol preferably has 2 to 4 hydroxyl groups in one molecule (hereinafter, may be abbreviated as bifunctional to tetrafunctional) and a molecular weight of 50 to 500. As such low molecular weight polyol, for example, bifunctional low molecular weight polyols such as ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,10-decanediol, etc.; trifunctional low molecular weight polyols such as glycerin, trimethylolpropane, etc.; tetrafunctional low molecular weight polyols such as erythritol, pentaerythritol, etc. are preferably used. Among them, trifunctional and / or tetrafunctional low molecular weight polyols are preferred. The weight average molecular weight of the rosin ester is preferably 500 to 2,000, and 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, "acrylic resin" refers to a polymer having an acrylic monomer as a constituent unit. Furthermore, "acrylic monomer" refers to a monomer having an acrylic group or a methacryloyl group, and "methacrylic and acrylic" may be collectively abbreviated as "(meth)acrylic". Furthermore, "methacrylate and acrylate" may be collectively abbreviated as "(meth)acrylate".

[0076] Acrylic monomers constituting the acrylic resin are listed below, but are not particularly limited as an example of an embodiment. The acrylic monomers may be used alone or in combination of two or more.

[0077] Examples of alkyl (meth)acrylates include 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. Among these, methyl (meth)acrylate is preferred.

[0078] For example, in order to obtain an 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, and 2-hydroxy-3-phenoxypropyl (meth)acrylate.

[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 binder resin] The chlorine content of the binder resin in the present invention is preferably 5% by mass or less, and may be 0. The chlorine content is more preferably 4% by mass or less, and even more preferably 0. Preferably, the content is 3% by mass or less, and more preferably 2% by mass or less. Also, it is particularly preferably 1% by mass or less or 0.5% by mass or less. The chlorine content is the content (% by mass) of chlorine atoms based on the mass of the binder resin. If the chlorine content is 5% by mass or less, the composition is excellent in environmental safety and is less likely to generate free chlorine.

[0082] The chlorine content can be measured by known methods such as ion chromatography (IC) and ICP mass spectrometry (ICP-MS). Measuring instruments include, for example, Shimadzu Corporation's LC-20ADsp for IC and Agilent Technologies' Agilent 7700x for ICP-MS. The chlorine content of the printed layer can be calculated simply from the chlorine content of each raw material constituting the printed layer using the following formula. The same applies to each of the other layers. Formula: Chlorine content (%) in total mass of binder resin solids = mass of chlorine in total mass of binder resin solids / total mass of binder resin solids (%) Formula: Chlorine content (%) in total mass of solids in printed layer = mass of chlorine in total mass of solids in printed layer / total mass of solids in printed layer (%)

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

[0084] [Degree of nitrification of binder resin] The binder resin in the present invention preferably has a degree of nitration of 1 mass % or less, including the case where it is 0. By having a degree of nitration of 1 mass % or less, NOx gas generation can be suppressed, and a safer recycled material can be provided. The degree of nitrification is the degree of esterification of nitric acid ester expressed as the nitrogen content (mass %), and for example, commercially available nitrocellulose usually has a nitrogen content of 10 to 12 mass %. The degree of nitration of the binder resin is more preferably 0.6% by mass or less, further preferably 0.4% by mass or less, and particularly preferably 0.2% by mass or less. The nitrification degree of the urethane resin is preferably 0.3% by mass or less, more preferably 0.2% by mass or less, and even more preferably 0.1% by mass or less. The nitrification degree of the resin L is preferably 0.8% by mass or less, more preferably 0.6% by mass or less, and even more preferably 0.4% by mass.

[0085] (Isocyanate-based hardener) In the packaging material of the present invention, in order to improve the laminate properties and tearability, the printing ink used to form the printed layer preferably contains an isocyanate-based curing agent. When the binder resin has a hydroxyl group, an amino group, or other active hydrogen group, the isocyanate-based curing agent crosslinks with the active hydrogen group, and when the binder resin does not have the active hydrogen group, the isocyanate-based curing agent crosslinks with itself only with the isocyanate-based curing agent, which is considered to improve the laminate strength, tearability, etc.

[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 even more preferably 1500 to 4000. The molecular weight distribution (Mw / Mn) of the isocyanate-based curing agent is 2.0 to 5.0. It is preferably 2.2 to 4.5, more preferably 2.5 to 4.0. When the weight average molecular weight and furthermore the Mw / Mn are within the above ranges, it is believed that the cohesive strength and adhesive strength of the printing ink are strengthened by the action with the urethane resin, resulting in good laminate strength and easy tearability.

[0087] The isocyanate-based curing agent is preferably a polyisocyanate including an adduct type polyisocyanate (adduct body), a biuret type polyisocyanate (biuret body), an isocyanurate type polyisocyanate (isocyanurate body), a bifunctional polyisocyanate, and the like. Examples of the adduct body, biuret body, and isocyanurate body include an adduct body obtained by reacting trimethylolpropane or other polyol with a diisocyanate, a biuret body in which a diisocyanate is dimerized and linked by a biuret bond, and an isocyanurate body obtained by a cyclic trimerization reaction of a diisocyanate. The diisocyanate may be selected from the above diisocyanates and used, and among them, preferred examples include 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. Adduct type polyisocyanates, biuret type polyisocyanates, and isocyanurate type polyisocyanates may be used in combination, and may also be used in combination with other polyisocyanates.

[0088] In order to set the weight average molecular weight and molecular weight distribution (Mw / Mn) of the isocyanate-based curing agent within the above range, it is possible to set the range by appropriately selecting diisocyanate, polyol, etc., the solid content mass ratio, the dripping speed of reactive raw materials such as polyisocyanate in the synthesis reaction, the stirring speed, the shape of the stirring blade, and the reaction temperature in the synthesis reaction. It is also effective to set the dripping speed and temperature range in a certain range when reacting polyamine and polyisocyanate to a certain range in order to set the molecular weight distribution within the specified range. In addition, it is effective to set the molecular weight distribution within a predetermined range by setting the charging ratio of the reaction raw materials to an appropriate ratio. Examples of the charging ratio include the NCO / OH ratio, which is the ratio of the isocyanate group of the polyol and the polyisocyanate, and the amino group / NCO ratio, which is the ratio of the amino group of the polyamine and the isocyanate group of the polyisocyanate. Reaction temperature control is important, and in synthesis using polyol and polyisocyanate, it is preferable to control it between 50 and 130°C, and when reacting polyamine and polyisocyanate, it is preferable to control it in the range of 10 to 50°C. In addition, the solid content is also important, and it is preferable to set the solid content during the reaction to 40 to 80 mass%. The reaction solvent is also important, and it is preferable to use ethyl acetate, normal propyl acetate, or 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 even more preferably 95:5 to 70:30. In the case where 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 even more preferably 95:5 to 70:30. This is because it is considered that within this range, the effects of the crosslinking and substrate adhesion become good, and good laminate properties and easy tearing properties are exhibited.

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

[0091] (Additives) The printing ink used to form the printed layer may further contain any additives as necessary, such as a leveling agent, an antifoaming agent, a wax, a silane coupling agent, a filler, a stabilizer, a plasticizer, an antioxidant, a light stabilizer such as an ultraviolet absorber, a dispersant, a thickener, a drying agent, a lubricant, an antistatic agent, and a crosslinking agent.

[0092] (gravure printing) The printing ink used to form the printed layer is preferably a gravure ink or a flexographic ink, more preferably a gravure ink. The printed layer is preferably formed by a gravure printing method or a flexographic printing method, more preferably by a gravure printing method.

[0093] (Photogravure version) In the gravure printing method, the gravure plate is a cylindrical metal plate, and recesses are made for each color by engraving, etching, or laser. There are no restrictions on the use of engraving and laser, and they can be set arbitrarily according to the pattern. Lines per page are appropriately set at 100 to 300 lines, and the higher the line count, the finer the printing. The thickness of the printing layer is preferably 0.1 μm to 100 μm.

[0094] (gravure printing machine) In the gravure printing method, one printing unit in the gravure printing machine is equipped with the gravure plate and doctor blade. There are many printing units, and printing units corresponding to organic solvent-based printing inks and picture inks can be set, and each unit has an oven drying unit. Printing is performed by rotary printing, and a roll-up printing method is used. The type of plate and the type of doctor blade are appropriately selected according to the specifications.

[0095] <Adhesive layer> The adhesive layer in the present invention comprises 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, and examples thereof include polyester polyols, polyether polyols, polyurethane polyols, polyesteramide polyols, acrylic polyols, polycarbonate polyols, polycaprolactone polyols, polyvalerolactone polyols, polyolefin polyols, polyhydroxyalkanes, castor oil, and mixtures thereof, as well as ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 3-methyl-5-pentanediol, 1,6-hexanediol, neopentanediol, and the like. Glycols such as butyl glycol, methylpentane glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, bishydroxyethoxybenzene, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, and triethylene glycol; polyalkylene glycols having a number average molecular weight of 200 to 3,000; trifunctional or tetrafunctional aliphatic alcohols such as glycerin, trimethylolpropane, and pentaerythritol; and polyols obtained by adding the above-mentioned glycols or polyols to the above-mentioned trifunctional or tetrafunctional aliphatic alcohols. These may be used alone or in combination of two or more kinds.

[0097] The polyol compound (D) is preferably one containing a structural unit derived from a polyester polyol or a structural unit derived from a polyether polyol. It may also be a polyester polyol or a polyether polyol itself. Among these, the polyol compound (D) is preferably a urethane polyol containing a urethane structure.

[0098] The polyester polyol may be 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 ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, triethylene glycol, butylene glycol, neopentyl glycol, dineopentyl glycol, trimethylolpropane, glycerin, 1,6-hexanediol, 1,4-butanediol, 1,5-dimethylphenylsilyl, 1,6-dimethylphenylsilyl, 1,7-dimethylphenylsilyl, 1,8-dimethylphenylsilyl, 1,9-dimethylphenylsilyl, 1,10-dimethylphenylsilyl, 1,2-dimethylphenylsilyl, 1,3-dimethylphenylsilyl, 1,4-dimethylphenylsilyl, 1,5-dimethylphenylsilyl, 1,6 ... ,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) is subjected to an esterification reaction; polyester polyol obtained by ring-opening polymerization of lactones such as polycaprolactone, polyvalerolactone, and poly(β-methyl-γ-valerolactone); the above 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 diols and polyether triols. Examples of the polyether polyol include polyether diols obtained by polymerizing an oxirane compound such as ethylene oxide, propylene oxide, butylene oxide, or tetrahydrofuran with a bifunctional low molecular weight polyol such as water, ethylene glycol, or propylene glycol as an initiator; and polyether triols obtained by polymerizing an oxirane compound such as ethylene oxide, propylene oxide, butylene oxide, or tetrahydrofuran with a low molecular weight triol such as trimethylolpropane or glycerin as an initiator.

[0100] The polyol compound (D) containing a structural unit derived from a polyester polyol or a structural unit derived from a polyether polyol may be a polyester urethane polyol or a polyether urethane polyol obtained by further reacting the polyester polyol or the polyether polyol with a diisocyanate, or may be a compound obtained by further reacting the polyester polyol or the polyether polyol with an acid anhydride. Examples of the 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 acid anhydride include pyromellitic anhydride, mellitic anhydride, trimellitic anhydride, and trimellitic ester anhydride. Examples of the trimellitic 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 further preferably from 10,000 to 60,0000. In addition, when a polyol compound (D) having a molecular weight distribution (Mw / Mn) of 1.5 to 10 is used, This can improve the leveling property during application of the adhesive and the adhesion between layers. In particular, when the polyol compound contains a structural unit derived from a polyether polyol, the molecular weight distribution (Mw / Mn) is preferably 3.0 to 10.0, and more preferably 3.0 to 8.0. When the polyol compound contains a structural unit derived from a polyester polyol, the molecular weight distribution (Mw / Mn) is preferably 1.5 to 5.0, and more preferably 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 as long as it is for use in a normal two-liquid reactive adhesive and contains a functional group reactive with a hydroxyl group. By having an isocyanate group, the adhesive strength and cohesive force of the adhesive are increased, and the adhesive can be cured at a low temperature around room temperature.

[0104] As the isocyanate compound (I), diisocyanates or urethane prepolymers which are reaction products of diisocyanates and polyols are preferred, and 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-trimethylsilyl diisocyanate, tetra ... Representative examples include methylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, cyclohexane-1,4-diisocyanate, xylylene diisocyanate, isophorone diisocyanate, lysine diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, 1,3-bis(isocyanatemethyl)cyclohexane, methylcyclohexane diisocyanate, m-tetramethylxylylene diisocyanate, and dimer diisocyanate in which the carboxyl group of a dimer acid is converted to an isocyanate group. These can be used alone or in combination of two or more kinds. Among these, from the viewpoints of preventing yellowing and imparting flexibility for improving adhesion, it is preferable to use aliphatic diisocyanates such as hexamethylene diisocyanate and xylylene diisocyanate, and alicyclic diisocyanates such as isophorone diisocyanate, and from the viewpoints of compatibility with retort resistance, it is preferable to use an adduct such as trimethylolpropane, an isocyanurate, a biuret, or another polyisocyanate compound having three or more functional groups.

[0105] In one embodiment, the polyol compound (D) and the isocyanate compound (I) are preferably used so 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 the reactive adhesive, other components known for use in adhesives can be blended in the base agent or curing agent.

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

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

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

[0109] (Leveling agent, defoamer) The reactive adhesive may contain a known leveling agent or defoaming agent for the purpose of improving the appearance of the laminate. Examples of the leveling agent include polyether-modified polydimethylsiloxane, polyester-modified polydimethylsiloxane, aralkyl-modified polymethylalkylsiloxane, polyester-modified hydroxyl-containing polydimethylsiloxane, polyetherester-modified hydroxyl-containing polydimethylsiloxane, acrylic copolymer, methacrylic copolymer, polyether-modified polymethylalkylsiloxane, acrylic acid alkyl ester copolymer, methacrylic acid alkyl ester copolymer, and lecithin. Examples of the defoaming agent include silicone resins, silicone solutions, and copolymers of alkyl vinyl ethers, alkyl acrylates, and alkyl methacrylates. 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 mass %, more preferably 0.005 to 0.5 mass %, based on the solid content of the reactive adhesive.

[0110] (Other additives) Various additives may be blended into the reactive adhesive as long as they do not impair the effects of the present invention. Examples of 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, antiblocking agents, colorants, fillers, crystal nucleating agents, and catalysts for adjusting the curing reaction.

[0111] (Organic solvent) The reactive adhesive may be diluted with a solvent to adjust the viscosity to an appropriate level. As the organic solvent used in the reactive adhesive, those that are inactive against the polyisocyanate component, such as esters such as ethyl acetate, ketones such as methyl ethyl ketone, and aromatic hydrocarbons such as 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 comprise an intermediate substrate layer. The intermediate substrate preferably comprises a polyolefin resin. Furthermore, of the total mass of the intermediate substrate, the polyolefin resin preferably accounts for 50 mass% or more, more preferably 60 mass% or more, even more preferably 70 mass% or more, even more preferably 80 mass% or more, and particularly preferably 90 mass% or more. Moreover, the polyolefin resin is more preferably a polypropylene-based resin and / or a polyethylene-based resin, further preferably a polypropylene-based resin, and particularly preferably a polypropylene-based resin that is a copolymer with ethylene and / or butene. Examples of intermediate substrates 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. Gas barrier substrates, for example, plastic substrates having an inorganic vapor deposition layer of aluminum, silica, alumina, or the like, or plastic substrates having a layer of a mixture of organic and inorganic components, are preferred.

[0113] <Sealant> The inner layer of the sealant is in direct contact with the packaged item and serves to protect the packaged item. In order to form the laminate into a bag, it is preferable that the innermost layer of the sealant has heat sealability. The sealant preferably contains a polyolefin resin. Furthermore, of the total mass of the sealant, the polyolefin resin preferably accounts for 50 mass% or more, more preferably 60 mass% or more, even more preferably 70 mass% or more, even more preferably 80 mass% or more, and particularly preferably 90 mass% or more. Moreover, the polyolefin resin is more preferably a polypropylene-based resin and / or a polyethylene-based resin, further preferably a polypropylene-based resin, and particularly preferably a polypropylene-based resin that is a copolymer with ethylene and / or butene. Examples of materials that make up the sealant include low density polyethylene (LDPE), linear low density polyethylene (LLDPE), medium density polyethylene (MDPE), high density polyethylene (HDPE), and Examples of the sealant include polyolefin resins such as 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 may be composed of two or more layers. In order to suppress shrinkage during heat sealing, the sealant is preferably a non-stretched film made of the above-mentioned resin.

[0114] The thickness of the sealant is not particularly limited and is appropriately set depending on the application of the laminate and the type and properties of the packaged goods, but is usually preferably 10 to 200 μm. In addition, in the case of a pouch (particularly 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 a sealant having an inorganic layer such as aluminum, silica, and alumina, or an organic layer such as ethylene-vinyl alcohol copolymer, polyvinyl alcohol, etc. It may also be a composite substrate by coextrusion or a blended opalescent substrate such as a pigment.

[0116] <Manufacturing method of packaging materials> The method for producing a 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 may be formed by applying it to a sealant.

[0117] A preferred embodiment is, for example, a mode in which an adhesive is applied onto the printed layer, and then a sealant is attached. When the packaging material further has an intermediate substrate layer, a preferred embodiment includes a step of first attaching the printed layer and the intermediate substrate with an adhesive, and then attaching the intermediate substrate and the sealant. The above configuration is optional and is not particularly limited.

[0118] The method for applying the adhesive is not particularly limited, and examples of devices 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 microgravure coater. The coating amount of the solid content of the adhesive composition is not particularly limited and can be appropriately selected depending on the application, and is usually 0.5 to 6.0 g / m 2 In the case where the adhesive composition is a solventless type, the adhesive composition is in the range of 1.0 to 3.0 g / m 2 , and 1.0 to 5.0 g / m for solvent-based 2 The range is preferably used.

[0119] The packaging material thus obtained is cut to a predetermined size, and the edges are heat-sealed with the sealants joined together to form a bag. The heat-sealing temperature is preferably 50 to 250°C, more preferably 80 to 180°C. The heat-sealing pressure is 1 to 5 kg / cm. 2The conditions are as follows. One sheet of packaging material may be folded and the edges heat sealed, or two or more sheets of packaging material may be heat sealed. Also, a bag made of packaging material may be one in which all openings are heat sealed after the contents are packed. EXAMPLES

[0120] The present invention will be described in detail below 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 % by mass unless otherwise noted.

[0121] <Method for measuring amine value> The amine value was calculated by the following method in accordance with JIS K0070, in terms of the equivalent amount of hydrochloric acid and the equivalent amount of potassium hydroxide required to neutralize the amino groups contained in 1 g of resin. 0.5 to 2 g of sample was precisely weighed out (sample solid content: Sg). 50 mL of a mixed solution of methanol / methyl ethyl ketone = 60 / 40 (mass ratio) was added to the precisely weighed sample to dissolve it. Bromophenol blue was added to the obtained solution as an indicator, and the obtained solution was titrated with 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 set as the endpoint, and the titration amount (A mL) at this point was used to calculate the amine value according to the following (Equation 1). (Formula 1) Amine value = (A x f x 0.2 x 56.108) / S [mgKOH / 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 by measuring the molecular weight distribution using a GPC (gel permeation chromatography) device (HLC-8220 manufactured by Tosoh Corporation) and calculating the molecular weight converted using polystyrene as a standard substance. The measurement conditions are shown below. Columns: The following columns were used in series connection: Tosoh Corporation's TSKgel Super HM-L Tosoh Corporation's TSKgel Super HM-L Tosoh Corporation's TSKgel Super HM-M Tosoh Corporation's TSK gelguard column Super H-H Detector: RI (differential refractometer) Measurement conditions: Column temperature 40℃ Eluent: Tetrahydrofuran Flow rate: 1.0mL / min

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

[0124] <Acid value measurement method> It was determined according to the method described in JIS K0070.

[0125] [Synthesis Example 1-1] (Synthesis of polyester polyol A1) In a round-bottom flask equipped with a stirrer, a thermometer, a water divider and a 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 parts of tetrabutyl titanate were charged, and esterification was carried out for 8 hours at 230°C under a nitrogen stream while removing water generated by condensation. After confirming that the acid value of the polyester was 15 or less, the degree of vacuum was gradually increased using a vacuum pump to terminate the reaction. As a result, polyester polyol A1 with a number average molecular weight of 2000, a hydroxyl value of 56.1 mgKOH / g and an acid value of 0.3 mgKOH / 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-based urethane resin B1) In a four-neck 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 parts of tin 2-ethylhexanoate were charged, and reacted for 6 hours at 120 ° C under a nitrogen stream, 7.5 parts of propyl acetate were added, and the mixture was cooled to obtain a solution of a terminal isocyanate prepolymer. Next, the solution of the terminal isocyanate prepolymer obtained was gradually added at room temperature to a mixture of 1.60 parts of isophorone diamine (hereinafter also abbreviated as IPDA), 0.12 parts of dibutylamine (hereinafter also abbreviated as DBA), 34 parts of ethyl acetate, and 21 parts of isopropyl alcohol (hereinafter also abbreviated as IPA), and then reacted for 1 hour at 50 ° C to obtain a polyester urethane resin B1 solution with a solid content of 30%, a mass average molecular weight of 70,000, and an amine value of 4 mgKOH / 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) Solutions of polyester-based urethane resins B2 to B5 were obtained in the same manner as in Synthesis Example 2-1, except that the raw materials and their charging ratios were used as shown in Table 2. The molecular weight distributions are shown in the same table. The abbreviations in the table stand for the following: IBPA: Iminobispropylamine

[0130] [Table 2]

[0131] In the ink preparation examples, the following were used: Polyvinyl butyral resin solution: A 30% solids solution of polyvinyl butyral resin (glass transition point 70°C, weight average molecular weight 50,000, chlorine content 0% by mass, degree of nitration 0% by mass) having vinyl alcohol units, vinyl acetate units, and vinyl butyral units and containing 73% by mass of butyral ring groups in a 1 / 1 ethyl acetate / isopropanol mixed solvent. Vinyl chloride-vinyl acetate copolymer resin solution: Vinyl chloride-vinyl acetate copolymer resin (Solvin TA3, manufactured by Nisshin Chemical Industry Co., Ltd., chlorine content 47.1% by mass, nitrification degree 0% by mass) in ethyl acetate solution with a solid content of 30% Cellulose-based 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 (solid content 30% isopropanol solution) Rosin resin solution: Hariestar P, manufactured by Harima Chemicals, rosin modified pentaerythritol ester, 30% solids in ethyl acetate solution Acrylic resin solution: BR-105, Mitsubishi Chemical Corporation Acrylic resin, weight average molecular weight 60,000, glass transition point 50°C, acid value 3.5mgKOH / g, ethyl acetate solution with 30% solid content CI Pigment Yellow 14: Toyo Color Co., Ltd. (chlorine content 10.8% by mass, nitrification rate 0% by mass)

[0132] [Ink Preparation Example 3-1] (Preparation of Ink C1) 5 parts of CI Pigment Blue 15:3 (manufactured by Toyo Color Co., Ltd., 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, and 10 parts of mixed solvent (propyl acetate / IPA = 70 / 30 (mass ratio)) were stirred and mixed and ground in a sand mill, and then 30 parts of polyester-based urethane resin (B) and 30 parts of mixed solvent (normal propyl acetate / isopropyl alcohol = 70 / 30 (mass ratio)) were stirred and mixed to prepare Ink C. I got 1.

[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] [Isocyanate-based hardener synthesis example] (Isocyanate-based hardener F1) In a nitrogen gas atmosphere, 15 parts of trimethylolpropane, 60.3 parts of toluene-2,4-diisocyanate, and ethyl acetate that had been dehydrated in advance were mixed in a reactor equipped with an agitator. The mixture was stirred at 50° C. for 3 hours at a stirring speed of 150 rpm to obtain an isocyanate-based curing agent F1. F1 had a weight average molecular weight of 1200, Mw / Mn of 2.5, and a solid content of 70% by mass.

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

[0137] [Adhesive Synthesis Example 4-1] (Synthesis of Polyol Compound D1) A reaction vessel equipped with a stirrer, a thermometer, a reflux condenser, a dripping tank and a nitrogen gas inlet tube was charged with 40 parts of a bifunctional polypropylene glycol having a number average molecular weight of about 2,000, 30 parts of a bifunctional polypropylene glycol having a number average molecular weight of about 400, 10 parts of a trifunctional polypropylene glycol having a number average molecular weight of about 400, 20 parts of a bifunctional polyether polyol ECOPROL 2000 having a number average molecular weight of about 2000, and 26 parts of tolylene diisocyanate, and the mixture was heated at 80 to 90 ° C for 5 hours while stirring under a nitrogen gas flow to perform a urethane reaction. During the urethane 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 parts of phosphoric acid was added to the obtained polyether urethane polyol, and the solid concentration was adjusted to 75% with ethyl acetate to obtain a polyol compound D1 solution. The weight average molecular weight of the polyol compound D1 was 36,000, and the molecular weight distribution (Mw / Mn) was 3.5.

[0138] [Adhesive Synthesis Example 4-2] (Synthesis of Polyol Compound D2) In a reaction vessel equipped with a stirrer, a thermometer, a reflux condenser, a dropping tank 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 the reaction was carried out by heating at 80 to 90 ° C for 5 hours while stirring under a nitrogen gas flow. 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. 0.01 parts of phosphoric acid and 0.02 parts of DYNASYLAN GLYMO were added to the obtained polyether urethane polyol, and the solid concentration was adjusted to 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) A reaction vessel equipped with a stirrer, a thermometer, a reflux condenser, a dropping tank and a nitrogen gas inlet tube was charged with 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, and the reaction was carried out by heating at 80 to 90 ° C for 5 hours while stirring under a nitrogen gas flow. During the urethanization reaction, 0.2% of Orgatics TC-100 was added as a reaction catalyst to promote the reaction, and a polyether urethane polyol was obtained. 0.01 parts of phosphoric acid and 0.02 parts of DYNASYLAN GLYMO were added to the obtained polyether urethane polyol, and the solid concentration was adjusted to 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] [Comparative adhesive synthesis example 4-1] (Synthesis of polyol compound E1) Into a reaction vessel equipped with a stirrer, a thermometer, a reflux condenser, a dropping tank, and a nitrogen gas inlet tube, 15 parts of bifunctional polypropylene glycol having a number average molecular weight of about 2,000, 15 parts of 65 parts of bifunctional polypropylene glycol, 20 parts of trifunctional polypropylene glycol with a number average molecular weight of about 400, and 36 parts of tolylene diisocyanate were charged into a reaction vessel, and the mixture was heated at 80 to 90 ° C for 5 hours while stirring under a nitrogen gas flow to carry out a urethane reaction. During the urethane reaction, 0.2% of Orgatics TC-100 was added as a reaction catalyst to promote the reaction, and a polyether urethane polyol was obtained. 0.01 parts of phosphoric acid and 0.02 parts of DYNASYLAN GLYMO were added to the obtained polyether urethane polyol, and the solid 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) In a reaction vessel equipped with a stirrer, a thermometer, a reflux condenser, a dropping tank 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 esterification reaction was carried out at 240 ° C. After a predetermined amount of water was distilled off, the pressure was gradually reduced to 1 mmHg or less and a deglycolization reaction was carried out at 250 ° C. 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. 1 part of trimellitic anhydride (TMA) was added to this polyester polyol and reacted at 180 ° C. for 2 hours, after which 0.2 parts of DYNASYLAN GLYMO was added and 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) A reaction vessel equipped with a stirrer, a thermometer, a reflux condenser, a dropping tank and a nitrogen gas inlet tube was charged with 15 parts of ethylene glycol (EG), 10 parts of 1,6-hexanediol, 20 parts of neopentyl glycol, 0.5 parts of trimethylolpropane (TMP), 32 parts of isophthalic acid and 20 parts of succinic acid, and an esterification reaction was carried out at 240°C. After a predetermined amount of water was distilled off, the pressure was gradually reduced to 1 mmHg or less and a deglycolization reaction was carried out at 250°C for 4.5 hours to obtain a polyester polyol. Then, 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, after which 0.2 parts of DYNASYLAN GLYMO was added, and the mixture was diluted with ethyl acetate to a non-volatile content of 60%, to obtain a polyol compound D5 solution. The weight average molecular weight of the 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) In a reaction vessel equipped with a stirrer, a thermometer, a reflux condenser, a dropping tank and a 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 esterification reaction was carried out at 240°C. After a predetermined amount of water was distilled off, the pressure was gradually reduced to 1 mmHg or less and a deglycolization reaction was carried out at 250°C for 5 hours to obtain a polyester polyol. Then, 1 part of tolylene diisocyanate was added and reacted at 150°C for 2 hours to obtain a polyester polyurethane polyol. 1 part of trimellitic anhydride was added to this polyester polyol and reacted at 180°C for 2 hours, 0.2 parts of DYNASYLAN GLYMO was added to this polyester polyurethane polyol, and then it was diluted with ethyl acetate to a non-volatile content of 60%, to obtain a polyol compound D6 solution. The weight average molecular weight of the polyol compound D6 was 26000 and the molecular weight distribution (Mw / Mn) was 2.2.

[0145] [Adhesive synthesis example 5-4] (Synthesis of polyol compound D7) In a reaction vessel equipped with a stirrer, a thermometer, a reflux condenser, a dropping tank and a 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 esterification reaction was carried out at 240°C. After a predetermined amount of water was distilled off, the pressure was gradually reduced to 1 mmHg or less and a deglycolization reaction was carried out at 250°C for 5 hours to obtain a polyester polyol. 0.5 parts of DYNASYLAN AMEO was added to this polyester polyol, and then the mixture was diluted with ethyl acetate to a non-volatile content of 60%, to obtain a polyol compound D7 solution. The weight average molecular weight of the polyol compound D7 was 22000 and the molecular weight distribution (Mw / Mn) was 1.9.

[0146] [Table 5]

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

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

[0149] [Example 1] (Preparation of packaging material G1) Ink C1 was diluted with a propyl acetate / IPA mixed solvent (mass ratio 70 / 30) so that the viscosity in a Zahn cup #3 (manufactured by Rigo) was 15 seconds (at 25°C), and printed on the corona-treated surface of a single-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 matter (OPP). The coating amount of the printed layer after drying was 2.5 g / m 2 It was decided. A solution prepared by adding 1 part of polyol compound D1 solution, 1 part of isocyanate compound F3 solution, and ethyl acetate to adjust the non-volatile content to 30% was applied onto the printed layer of the above printed matter using a gravure roll coater, and the solvent was dried in an oven to obtain a coating of 2.5 g / m 2 An adhesive layer was formed, and the resultant was laminated with an unstretched polypropylene (CPP) film (thickness: 30 μm, surface corona discharge treated) using a laminator, and the resulting mixture was kept at 40° C. for 3 days to prepare packaging material G1. Composition: Biaxially oriented polypropylene (OPP) film (thickness 20 μm) / Printing layer / Adhesive layer / Unoriented polypropylene (CPP) film (thickness 30 μm, surface corona discharge treatment)

[0150] In the following examples and comparative examples, the following were used. NY: Surface corona discharge treated biaxially oriented nylon film (thickness 15μm) LLDPE30μm: Surface corona discharge treatment linear low density polyethylene film (thickness 30μm) LLDPE150μm: Surface corona discharge treatment Linear low density polyethylene film (thickness 150μm)

[0151] [Examples 2 to 21] (Preparation of packaging materials G2 to 21) In the same manner as in Example 1, packaging materials G2 to G21 were obtained according to the compositions shown in Table 6. In Examples 18 and 19, the viscosity of the ink was adjusted with a propyl acetate / IPA mixed solvent (mass ratio 70 / 30), and then 3 parts each of isocyanate-based hardeners F1 and F2 were added per 100 parts of ink.

[0152] [Comparative Examples 1 to 3] (Preparation of Packaging Materials H1 to H3) In the same manner as in Example 1, packaging materials H1 to H3 were obtained according to the compositions shown in Table 6.

[0153] The following characteristics were evaluated using the above packaging material, and the results are shown in Table 6.

[0154] (Laminate strength) The packaging materials obtained in the above Examples and Comparative Examples were cut into pieces 150 mm long and 15 mm wide, opened at the ink / OPP film or ink / NY film interface, and the laminate strength in the 90° direction was measured using a tensile tester. [Evaluation Criteria] A (excellent): 1.5N / 15mm or more B (Good): 1.0N / 15mm or more, less than 1.5N / 15mm C (Acceptable): 0.8N / 15mm or more, less than 1.0N / 15mm D (unacceptable): 0.5N / 15mm or more, less than 0.8N / 15mm E (poor): less than 0.5N / 15mm The evaluation of practical use is A to C.

[0155] (Easy tearability) Samples were prepared from the packaging materials obtained in the above Examples and Comparative Examples in accordance with JIS K7128-1:1998, and evaluated for tear resistance using an Intesco 201 universal tensile tester. [Evaluation Criteria] A (Excellent): Less than 0.5N B (Good): 0.5N or more and less than 1.0N C (Acceptable): 1.0N or more and less than 1.5N D (unacceptable): 1.5N or more and less than 2.0N E (poor): 2.0N or more The evaluation of practical use is A to C.

[0156] (Recyclability evaluation) The packaging materials obtained in the above Examples and Comparative Examples were cut to a size of 4 cm x 4 cm, washed with water and dried. The pieces of packaging material were fed into a single-screw extruder, melted and kneaded at a screw speed of 250 rpm and 220°C, and extruded from the discharge part of the extrusion device using a 150 mesh filter at a pressure of 4 MPa. Thereafter, the pieces were immediately cut with a pelletizer and immersed in cold water to cool. In this way, pellets of recycled plastic recycled from the packaging material were obtained. Then, the recycled plastic pellets were extruded at 220°C using a T-die extruder to produce a film-shaped molded product with a thickness of 50 μm. The obtained film was cut into 0.5 m pieces. 2 The number of foreign objects and bubbles that could be visually identified per unit area was counted and evaluated according to the following criteria. [Evaluation Criteria] A (Excellent): The number of foreign objects or bubbles is less than 40. B (Good): The number of foreign objects or bubbles is between 40 and 80. C (Acceptable): Foreign matter, number of bubbles: 80 or more but less than 120, D (Not acceptable): Foreign matter, bubbles number 120 or more but less than 200, E (poor): The number of foreign bodies or bubbles is 200 or more. The evaluation of practical use is A to C.

[0157] [Table 6]

[0158] [Table 6]

Claims

1. A packaging material having a substrate, a printing layer, an adhesive layer, and a sealant, The packaging material contains 80% by mass or more of polyolefin resin in the total mass of the packaging material, the printed layer contains a pigment and a binder resin, and the binder resin contains a polyester-based urethane resin (B); The molecular weight distribution (Mw / Mn) of the polyester-based urethane resin (B) is 2.0 to 8.0, the polyester-based urethane resin (B) contains a structural unit derived from a polyester that is a condensation product of a dibasic acid and a diol, the diol contains a branched diol and a linear diol, A packaging material, in which the adhesive layer is made 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, excluding a packaging material having a configuration in which at least a first substrate, a printed layer, a polyurethane-based adhesive layer and a second substrate are laminated in this order from the outer layer side, the polyurethane-based adhesive layer is provided in contact with the second substrate, and the polyurethane-based adhesive layer is used to remove the second substrate).

2. The packaging material according to claim 1, wherein the polyol compound (D) contains a structural unit derived from a polyether polyol, and the molecular weight distribution (Mw / Mn) of the polyol compound (D) is 3.0 to 10.

0.

3. The packaging material according to claim 1, wherein the polyol compound (D) contains a structural unit derived from a polyester polyol, and the molecular weight distribution (Mw / Mn) of the polyol compound (D) is 1.5 to 5.

0.

4. The packaging material according to any one of claims 1 to 3, wherein the binder resin has a chlorine content of 5 mass% or less.

5. A packaging material described in any one of claims 1 to 4, wherein the reactive adhesive contains phosphoric acid and / or a phosphoric acid derivative.

6. A packaging material described in any one of claims 1 to 5, wherein the dibasic acid includes sebacic acid and / or succinic acid.

7. A packaging material described in any one of claims 1 to 6, wherein the reactive adhesive includes a silane coupling agent.

8. The packaging material according to any one of claims 1 to 7, 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.

9. The packaging material according to any one of claims 1 to 8, wherein the content of the pigment is 30 mass % or less based on the total mass of the printed layer.

10. The packaging material according to any one of claims 1 to 9, wherein the printed layer further contains an isocyanate-based curing agent having a weight average molecular weight of 800 to 8,000.

11. The packaging material according to any one of claims 1 to 10, wherein the substrate and the sealant comprise a polyolefin resin.

12. The packaging material according to claim 11, wherein the polyolefin resin is a polypropylene-based resin.

13. The packaging material according to any one of claims 1 to 12, wherein the chlorine content is 0.4 mass% or less based on the total mass of the packaging material.

14. A method for producing a packaging material having a substrate, a printing layer, an adhesive layer, and a sealant, and containing 80% by mass or more of an olefin resin in the total mass (excluding packaging materials having a configuration in which at least a first substrate, a printing layer, a polyurethane-based adhesive layer, and a second substrate are laminated in this order from the outer layer side, the polyurethane-based adhesive layer is provided in contact with the second substrate, and the polyurethane-based adhesive layer is used to remove the second substrate), comprising: The method includes a step of printing a gravure ink containing a polyester-based urethane resin (B) on a substrate 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 molecular weight distribution (Mw / Mn) of the polyester-based urethane resin (B) is 2.0 to 8.0, the polyester-based urethane resin (B) contains a structural unit derived from a polyester that is a condensation product of a dibasic acid and a diol, the diol contains a branched diol and a linear diol, The polyol compound (D) has a molecular weight distribution (Mw / Mn) of 1.5 to 10.0.