Packaging material and manufacturing method thereof

Abstract

To provide a packaging material excellent in wet friction resistance, surface glossiness, releasability, stab resistance, and heat sealability.SOLUTION: A packaging material has a heat seal layer, a paper base material containing a sizing agent, and a printing layer in this order. The paper base material is in contact with the printing layer. The printing layer contains a styrene-acrylic copolymer resin and / or a styrene-maleic acid copolymer resin. The sizing agent contains at least one selected from the group consisting of a rosin resin, an alkenyl succinate, an alkyl ketene dimer, a polyvinyl alcohol resin, and a starch resin.SELECTED DRAWING: None

Description

Technical Field

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

Background Art

[0002] In recent years, it has been common for product packages and other packaging materials (packages) to be provided with a printed layer and surface protection. The printed layer imparts design, cosmetic, and luxuriousness, etc., and the surface protection layer protects the packaging material from physical contact, so the industrial value is great.

[0003] Generally, plastic films are mainly used in the configuration of packages, and in particular, laminated packaging materials have been often used. For example, Patent Document 1 describes an invention of a laminated packaging material composed of a base material, a printed layer, an adhesive layer, and a sealant layer, in which a biomass resin is used in the printed layer and the adhesive layer. However, in the first place, laminated packaging materials use a large amount of plastic films made of petroleum-derived materials. Therefore, there is a demand for a paper-based packaging material that is environmentally friendly, carbon neutral, and can further reduce the amount of plastic used, and technical development has been carried out.

[0004] Patent Document 2 describes an invention related to a laminate having a paper base material containing a sizing agent, a printed layer containing a styrene-acrylic copolymer resin, an anchor coat layer, and a heat seal layer in this order. However, in the laminate, the opposite surface of the printed layer of the paper base material is exposed, and the laminate cannot be protected from water, oil, etc. In addition, there is no description at all about surface glossiness, releasability, and puncture resistance.

[0005] Therefore, a packaging material that can satisfy as a packaging material excellent in water friction resistance, surface glossiness, releasability, puncture resistance, and heat sealability in a paper-based packaging material has not yet been found.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0007] An object of the present invention is to provide a packaging material excellent in water-resistant friction, surface gloss, releasability, puncture resistance, and heat sealability.

Means for Solving the Problems

[0008] As a result of intensive studies on the above problems, the present inventor has found that the above problems can be solved by using the packaging material described below, and has thus completed the present invention.

[0009] That is, the present invention is a packaging material having a heat-sealing layer, a paper base material containing a sizing agent, and a printing layer in this order, wherein the paper base material is in contact with the printing layer, and the printing layer contains a styrene-acrylic copolymer resin and / or a styrene-maleic acid copolymer resin, and relates to a packaging material.

[0010] Further, the present invention relates to the above packaging material, wherein the sizing agent contains at least one selected from the group consisting of a rosin resin, an alkenyl succinate, an alkyl ketene dimer, a polyvinyl alcohol resin, and a starch resin.

[0011] Further, the present invention relates to the above packaging material, wherein the gloss value measured by JIS Z 8741 of the printing layer is 15 to 60.

[0012] Further, the present invention relates to the above packaging material, wherein the printing layer further contains a sugar-derived resin and / or a rosin resin.

[0013] Further, the present invention relates to the above packaging material, wherein the printing layer contains an ink layer and / or a surface protection layer.

[0014] The present invention also relates to the packaging material, wherein the heat-sealing layer contains at least one selected from the group consisting of ethylene vinyl acetate copolymer resin, acrylic resin, and ethylene-based ionomer.

[0015] The present invention also relates to the packaging material, wherein the content of the sizing agent per unit area in the paper base material is 0.3 to 1.0 g / m 2 as described above.

[0016] The present invention also relates to a method for manufacturing a packaging material having a heat-sealing layer, a paper base material containing a sizing agent, and a printing layer, Step 1 of papermaking a mixture of plant fibers and a sizing agent to obtain a paper base material containing the sizing agent, and at least one of Step 2 of applying a coating agent containing a sizing agent onto the paper base material to obtain a paper base material containing the sizing agent, Step 3 of forming a printing layer by printing a printing ink or an overcoat agent containing a styrene acrylic copolymer resin and / or a styrene maleic acid copolymer resin on one surface of the paper base material containing the sizing agent, The present invention relates to a method for manufacturing a packaging material, which includes Step 4 of applying a heat-sealing agent onto the other surface of the paper base material to form a heat-sealing layer.

Effects of the Invention

[0017] According to the present invention, it has become possible to provide a packaging material excellent in water-resistant friction, surface gloss, releasability, puncture resistance, and heat-sealing properties.

Modes for Carrying Out the Invention

[0018] Hereinafter, embodiments of the present invention will be described in detail. However, the description of the constituent elements described below is an example of an embodiment of the present invention, and the present invention is not limited to these contents unless it exceeds the gist thereof.

[0019] In the following description, "parts" means "parts by mass" and "%" means "% by mass" unless otherwise specified. In addition, the packaging material may be simply abbreviated as "laminate", which has the same meaning. In the following description of the present invention, the "printing ink" refers to an ink containing a pigment or other colorant for forming a printing layer, and the overcoat agent refers to a coating agent that does not contain a pigment or other colorant for forming a surface protection layer, but does not exclude a small amount of colorant or the like that is inadvertently mixed in.

[0020] [Packaging material] A packaging material having a heat-sealing layer, a paper substrate containing a sizing agent, and a printing layer in this order, wherein the paper substrate is in contact with the printing layer, and the printing layer contains a styrene-acrylic copolymer resin and / or a styrene-maleic acid copolymer resin. In the packaging material of the present invention, since the paper substrate contains a sizing agent, the affinity between the sizing agent in the paper substrate and the styrene-acrylic copolymer resin and / or the styrene-maleic acid copolymer resin is increased. As a result, the adhesion between the paper substrate and the printing layer is improved, and further, the styrene-acrylic copolymer resin and / or the styrene-maleic acid copolymer resin are suppressed from excessively penetrating into the paper substrate. Furthermore, by providing a heat-sealing layer on the opposite side of the printing layer, the fibers of the paper are filled and the bleeding of the printing layer is prevented, so that the printing layer becomes smooth. Due to the above synergistic effect, it is excellent in water resistance to friction, surface gloss, releasability, puncture resistance, and heat sealability. However, the above is based on scientific considerations, and the present invention is not limited only to the above actions.

[0021] As examples of the laminated structure of the above packaging material, the following can be preferably cited. In the following examples, " / " means the boundary of each layer. In this specification, sized paper means a paper substrate containing a sizing agent. Also, the printing layer may be an ink layer and / or a surface protection layer, and the printing layer is laminated so as to be in contact with the paper substrate. The printing layer preferably includes at least one of an ink layer or a surface protection layer. Also, a form in which an ink layer and a surface protection layer are laminated and the paper substrate is in contact with the ink layer is also preferable. Heat-sealing layer / Sized paper / Ink layer Heat-sealing layer / Sized paper / Surface protection layer Heat-sealing layer / Sized paper / Ink layer / Surface protection layer Note that the configuration of the laminate is not limited to the above. In this specification, the surface of the printing layer that comes into contact with air is referred to as the printing layer surface or the outermost surface of the printing layer.

[0022] <Gloss value of the packaging material> The printing layer of the packaging material of the present invention preferably has a gloss value of 15 to 60. More preferably, it is 50 or less, still more preferably 40 or less, and particularly preferably 15 to 35. The above gloss value is the 60-degree gloss value (Gs(60)) measured in accordance with JIS Z 8741:1997. When it is 60 or less, fine irregularities occur on the surface of the printing layer, and the contact area with water can be reduced, so the water-resistant friction resistance is excellent. Note that the above gloss value does not refer to the glossiness (specular reflection) of a metal layer such as an aluminum vapor deposition layer inside the packaging material, but refers to the gloss value of the outermost surface of the printing layer.

[0023] From the viewpoint of setting the gloss value of the printing layer within the above range, in addition to the printing layer containing a styrene-acrylic copolymer resin and / or a styrene-maleic acid copolymer resin, the coating amount of the printing layer is 1 to 16 g / m 2 It is preferably, 2.5 to 12 g / m 2 It is more preferably, 4 to 8 g / m 2 It is particularly preferably.

[0024] [Paper substrate containing a sizing agent] The paper substrate containing a sizing agent used in the present invention only needs to contain a sizing agent in the paper substrate, and the manufacturing method is not limited. For example, it can be obtained by adhering a mixture of plant fibers and the sizing agent described below to make paper by the method described in JP-A-2021-075827, etc., or it can also be obtained by coating a coating agent containing a sizing agent on the paper substrate and removing the volatile components. The content of the sizing agent per unit area in the paper substrate is preferably 0.01 to 5% by mass, more preferably 0.05 to 2% by mass, and still more preferably 0.1 to 1% by mass. When it is in the above range, the puncture resistance, surface glossiness, releasability, and water-resistant friction resistance are improved. The mass ratio of the content per unit area of the sizing agent in the paper base material to the content per unit area of the styrene-acrylic copolymer resin and / or styrene-maleic resin in the printing layer is preferably from 0.1:99.9 to 30:70, more preferably from 0.2:99.8 to 10:90, and still more preferably from 0.3:99.7 to 5:95. When within the above range, the puncture resistance, surface gloss, releasability, and water friction resistance are improved. When the printing layer has an ink layer and a surface protection layer, the content of each component in the printing layer is calculated from the total amount of the ink layer and the surface protection layer.

[0025] <Sizing agent> Examples of the sizing agent used in the present application include rosin resin, alkenyl succinic anhydride, alkyl ketene dimer, styrene-acrylic copolymer resin, styrene-maleic copolymer resin, maleic resin, polyvinyl alcohol resin, starch resin, casein resin, vinyl acetate resin, vinyl chloride resin, vinyl chloride-vinyl acetate copolymer resin, urethane resin, acrylic resin, epoxy resin, polysaccharide ester, styrene elastomer resin such as styrene-butadiene copolymer resin, etc. One kind of the above sizing agents may be used alone, or two or more kinds may be used in combination at an arbitrary ratio. Among them, it is preferably at least one selected from the group consisting of rosin resin, alkenyl succinate, alkyl ketene dimer, polyvinyl alcohol resin, and starch resin, more preferably rosin resin, alkenyl succinic acid, and alkyl ketene dimer salt, and still more preferably rosin resin.

[0026] <Coating agent containing sizing agent> The coating agent containing a sizing agent used in the present invention contains a sizing agent and a solvent, and is preferably aqueous from the viewpoint of environmental load. As the coating method of the coating agent containing a sizing agent, known methods can be used. For example, a sizing press machine such as a vertical two-roll size press coater, a horizontal two-roll size press coater, an inclined two-roll size press coater, a gate roll coater, or a rod metering size press can be used for coating.

[0027] <Additives other than the sizing agent> The paper base material containing a sizing agent used in the present invention may contain additives other than the sizing agent. For example, known additives such as yield improvers such as aluminum sulfate and polyacrylamide, paper strength enhancers such as urea formaldehyde resin and melamine formaldehyde resin, and fillers such as talc and kaolin can be used.

[0028] <Paper base material> The paper base material is not particularly limited, and known ones can be used. The paper base material made by the method described in JP-A-2021-075827 can be used, and a commercially available paper base material can also be used. Examples of commercially available paper base materials include medium paper, high-quality paper, newsprint, cardboard, art paper, cast paper, kraft paper, and the like. The basis weight of the paper base material is preferably 50 to 150 g / m 2 , more preferably 55 to 120 g / m 2 , still more preferably 60 to 90 g / m 2 . When it is within the above range, the puncture resistance, surface gloss, releasability, and water rubbing resistance are improved.

[0029] [Printing layer] The printing layer used in the present invention contains a styrene-acrylic copolymer resin and / or a styrene-maleic acid copolymer resin. The ink layer contains a colorant, and the surface protective layer does not contain a colorant. However, the surface protective layer does not exclude a small amount of colorant that has been inadvertently mixed in. From the viewpoint of water resistance, it is preferable that the printing layer includes a surface protective layer.

[0030] The printing layer can contain the [ink layer] described below, <other resins contained in the ink layer>. The mass ratio of the styrene-acrylic copolymer resin and / or styrene-maleic acid copolymer resin to other resins in the printing layer is preferably 99:1 to 15:85, more preferably 97:3 to 25:75, still more preferably 95:5 to 50:50, and particularly preferably 93:10 to 70:30. When within the above range, the packaging material is excellent in puncture resistance, releasability, and water friction resistance.

[0031] [Ink layer] The ink layer in the present invention is a layer containing a colorant, a styrene-acrylic copolymer resin and / or a styrene-maleic acid copolymer resin, and can be formed by printing, for example, on the surface opposite to the surface having the heat-sealing layer of a paper substrate using the printing ink described below. The printing layer is formed using printing ink, and the printing method can be appropriately selected from known printing methods such as the gravure printing method and the flexographic printing method, and preferably the gravure printing. The coating amount of the printing layer is preferably 0.1 to 12 g / m 2 and more preferably 0.3 to 7.2 g / m 2 and particularly preferably 0.5 to 3.6 g / m 2 When within the above range, the puncture resistance, surface glossiness, releasability, and water friction resistance of the packaging material are good. In this specification, the "ink layer" includes not only a single ink layer but also a layer formed by laminating a plurality of ink layers, and ink layers having different hues can be arbitrarily combined.

[0032] <Styrene-acrylic copolymer resin contained in the ink layer> The styrene-acrylic copolymer resin is preferably an aqueous resin. The aqueous resin may be a water-soluble resin or an aqueous emulsion resin, but an aqueous emulsion resin is preferred. Note that the water-soluble resin refers to a resin in which the styrene-acrylic copolymer resin itself dissolves in water alone.

[0033] The styrene-acrylic copolymer resin preferably has an acid group, and in that case, the acid value is preferably 20 to 200 mgKOH / g, more preferably 30 to 150 mgKOH / g, and even more preferably 80 to 120 mgKOH / g. When the styrene-acrylic copolymer resin has an acid group and the acid value is within the above range, the releasability and water-resistant friction resistance of the packaging material are good.

[0034] The weight average molecular weight of the styrene-acrylic copolymer resin is preferably 2000 to 600000, more preferably 50000 to 600000, and particularly preferably 70000 to 600000.

[0035] The glass transition temperature of the styrene-acrylic copolymer resin is preferably -20 to 80 °C, more preferably -10 to 60 °C, and even more preferably 0 to 40 °C.

[0036] When the weight average molecular weight and the glass transition temperature of the styrene-acrylic copolymer resin are within the above ranges, both the toughness and flexibility of the printing layer can be achieved, so the releasability and puncture resistance are good.

[0037] Commercially available products may be used as the styrene-acrylic copolymer resin. For example, X-1, YL-1098, PE-1304, KE-1060 manufactured by Starlight PMC, and Joncryl 60J, Joncryl PDX-6137A manufactured by BASF can be used.

[0038] <Styrene maleic acid copolymer resin contained in the ink layer> The styrene maleic acid copolymer resin is preferably used as a water-soluble resin. The styrene maleic acid copolymer resin preferably has an acid group, and in that case, the acid value is preferably 100 to 180 mgKOH / g, more preferably 120 to 160 mgKOH / g. When the styrene maleic acid copolymer resin has an acid group and the acid value is within the above range, the releasability and water-resistant friction resistance of the packaging material are good.

[0039] The weight average molecular weight of the styrene maleic acid copolymer resin is preferably from 1,500 to 50,000, more preferably from 4,000 to 30,000.

[0040] The glass transition temperature of the styrene maleic acid copolymer resin is preferably from 40 to 120°C, more preferably from 60 to 100°C.

[0041] When the weight average molecular weight and the glass transition temperature of the styrene maleic acid copolymer resin are within the above ranges, the water friction resistance and the puncture resistance of the packaging material are good.

[0042] As the styrene maleic acid copolymer resin, commercially available products may be used. For example, M-30 manufactured by Starlight PMC Co., Ltd. and Alaster series manufactured by Arakawa Chemical Co., Ltd. can be used.

[0043] <Other resins contained in the ink layer> The ink layer used in the present invention can further contain resins other than styrene-acrylic copolymer resin and / or styrene-maleic acid copolymer resin. For example, polylactic acid resin, urethane resin, polyamide resin, vinyl chloride resin, vinyl chloride-vinyl acetate copolymer resin, vinyl chloride-acrylic copolymer resin, sugar-derived resin, rosin resin, vinyl acetate resin, ethylene-vinyl acetate copolymer resin, vinyl acetate resin, acrylic resin, urethane-acrylic resin, styrene resin, styrene-allyl alcohol resin, maleic anhydride resin, maleic acid resin, rosin-modified maleic acid resin, cycloolefin resin, dammar resin, polyester resin, alkyd resin, terpene resin, phenol-modified terpene resin, ketone resin, cyclized rubber, chlorinated rubber, butyral, polyacetal resin, silicone resin, and modified resins thereof can be mentioned. Among them, it is preferably contains at least one selected from the group consisting of urethane resin, polyamide resin, and acrylic resin, and more preferably contains a sugar-derived resin and / or a rosin resin. As the sugar-derived resin and / or rosin resin, for example, the resins described in JP-A-2021-46522 and JP-A-2019-108529 can be used. The solid content mass ratio of the styrene-acrylic copolymer resin and / or styrene-maleic acid copolymer resin to the sugar-derived resin and / or rosin resin is preferably 80:20 to 20:80, and more preferably 60:40 to 30:70.

[0044] <Colorant contained in the ink layer> The ink layer preferably contains a colorant. The content of the colorant is preferably 1 to 60% by mass, more preferably 30 to 50% by mass, based on the total mass of the ink layer.

[0045] A pigment is preferably used as the colorant, and either an organic pigment or an inorganic pigment can be used as the pigment. As the organic pigment, it is preferable to use a pigment composed of an organic compound and / or an organometallic complex. As the inorganic pigment, those containing titanium oxide are preferable.

[0046] Specific examples of the organic pigment are indicated by the C.I. number of the Colour Index International (abbreviated as C.I.). Preferably, C.I. Pigment Red 57:1, C.I. Pigment Red 48:1, C.I. Pigment Red 48:2, C.I. Pigment Red 48:3, C.I. Pigment Red 146, C.I. Pigment Red 242, C.I. Pigment Yellow 83, C.I. Pigment Yellow 14, C.I. Pigment Orange 64, C.I. Pigment Orange 38, C.I. Pigment Orange 34, C.I. Pigment Orange 13, C.I. Pigment Yellow 180, C.I. Pigment Yellow 139, C.I. Pigment Red 185, C.I. Pigment Red 122, C.I. Pigment Red 178, C.I. Pigment Red 149, C.I. Pigment Red 144, C.I. Pigment Red 166, C.I. Pigment Violet 23, C.I. Pigment Violet 37, C.I. Pigment Blue 15, C.I. Pigment Blue 15:1, C.I. Pigment Blue 15:2, C.I. Pigment Blue 15:3, C.I. Pigment Blue 15:4, C.I. Pigment Blue 15:6, C.I. Pigment Green 7, C.I. Pigment Orange 34, C.I. Pigment Orange 64, C.I. Pigment Black 7. These may be used alone or in combination of two or more.

[0047] (Inorganic pigment) Examples of the inorganic pigment include titanium oxide, zinc oxide, zinc sulfide, barium sulfate, calcium carbonate, chromium oxide, silica, aluminum particles, mica, bronze powder, chrome vermilion, lead yellow, cadmium yellow, cadmium red, ultramarine, indigo, red iron oxide, iron black, titanium oxide, and zinc oxide. Aluminum has a leafing type or a non-leafing type, and the non-leafing type is preferred.

[0048] Titanium oxide may be of any of anatase type, rutile type, and brookite type in crystal structure. Among them, rutile type titanium oxide is preferably used because of its good pigment dispersibility. In the industrial production of titanium oxide, rutile ore or ilmenite ore (FeTiO3) is used as a raw material. There are two main production methods, namely the chlorine method and the sulfuric acid method, and either method may be used. In addition, in order to improve the printability in flexographic printing or gravure printing, titanium oxide is preferably surface-treated. Particularly preferred is that which is surface-treated with at least one metal selected from Si, Al, Zn, Zr, and their oxides.

[0049] In addition, titanium oxide preferably has an oil absorption amount of 14 to 35 ml / 100 g, more preferably 17 to 32 ml / 100 g, as measured by the measurement method specified in JIS K5101. Further, titanium oxide preferably has an average particle diameter (median particle diameter) of 0.2 to 0.3 μm as measured by a transmission electron microscope. Also, the total content of titanium oxide is preferably 1 to 60% by mass, more preferably 10 to 45% by mass, in 100% by mass of the printing ink. Note that a plurality of types of titanium oxide may be used in combination.

[0050] <Additives contained in the ink layer> Various additives can be contained in the ink layer of the present invention as needed. For example, a dispersant, wax, extender pigment, leveling agent, defoaming agent, and film-forming aid. Specifically, in order to improve abrasion resistance, a wax resin fine particle dispersion such as polyethylene wax, and in order to improve drying properties and coating film hiding properties, extender pigments such as calcium carbonate, kaolin, barium sulfate, aluminum hydroxide, clay, talc, etc., and in order to impart anti-slip properties, inorganic fine particles and adhesive resins (acrylic resin, vinyl acetate resin), a leveling agent in order to improve leveling properties, a defoaming agent in order to impart defoaming properties, basic compounds such as sodium hydroxide and potassium hydroxide in order to impart redissolubility, and various additives such as film-forming aids can be added.

[0051] <Printing ink> The ink layer is preferably formed of a printing ink containing the colorant, the binder resin, and a liquid medium (organic solvent, water, etc.).

[0052] (Aqueous medium) The printing ink preferably contains an aqueous medium. The aqueous medium refers to a liquid medium in which the water content is 50% by mass or more in the total mass. It is preferable that the main component (50% by mass or more) of the aqueous medium is water, and it can further contain a water-soluble organic solvent. Specifically, depending on the printing conditions (speed, plate depth, design, drying temperature), an alcohol-based organic solvent, a glycol-based organic solvent, etc. can be contained as the water-soluble organic solvent. The content of the aqueous medium is preferably 30% by mass or less, more preferably 20% by mass or less, based on the total amount of the overcoat agent. Here, the water-soluble organic solvent refers to a substance that is liquid at 25°C and does not phase-separate when mixed with water at 25°C in a 1:1 ratio. Examples of the water-soluble organic solvent preferably include ethanol, isopropanol, propylene glycol, etc.

[0053] Examples of the alcohol-based organic solvent include methanol, ethanol, propanol, isopropanol, isobutanol, normal butanol, tertiary butanol, hexanol, octanol, decanol, etc.

[0054] Examples of the glycol-based organic solvents include ethylene glycol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, ethylene glycol monooctyl ether, diethylene glycol, diethylene glycol monoethyl ether, diethylene glycol monopropyl ether, diethylene glycol monobutyl ether, triethylene glycol, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, triethylene glycol monopropyl ether, triethylene glycol monobutyl ether, propylene glycol, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, dipropylene glycol, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monopropyl ether, dipropylene glycol monobutyl ether, tripropylene glycol, tripropylene glycol monomethyl ether, tripropylene glycol monoethyl ether, tripropylene glycol monopropyl ether, tripropylene glycol monobutyl ether, dibutyl glycol, and the like. These may be used alone or in combination of two or more.

[0055] (Organic solvent) It is also preferable that the printing ink contains an organic solvent as a main component (50% by mass or more) of the liquid medium. As the organic solvent to be used, a mixed solvent composed of two or more organic solvents is preferable, and known organic solvents such as aromatic organic solvents such as toluene and xylene, ketone organic solvents such as methyl ethyl ketone and methyl isobutyl ketone, ethyl acetate, n-propyl acetate, isopropyl acetate, isobutyl acetate, ester organic solvents, and alcohol organic solvents such as methanol, ethanol, n-propanol, isopropanol, and n-butanol can be used. Among them, an organic solvent (non-toluene-based organic solvent) that does not contain aromatic organic solvents such as toluene and xylene is more preferable, and an organic solvent that does not contain aromatic organic solvents and / or ketone organic solvents such as methyl ethyl ketone (hereinafter referred to as "MEK") is even more preferable. In addition, in order to improve printing suitability, it is preferably a mixed solvent of an ester organic solvent and an alcohol organic solvent. The preferable mass ratio of the ester organic solvent to the alcohol organic solvent (ester organic solvent / alcohol organic solvent) is 50 / 50 to 90 / 10.

[0056] <Method for manufacturing printing ink> The printing ink used for forming the ink layer can be manufactured, for example, by dispersing a pigment in an organic solvent using a dispersing machine with a resin or the like, and then mixing a resin, various additives, an organic solvent, etc. into the obtained pigment dispersion. As the dispersing machine, generally used ones such as a roller mill, a ball mill, a pebble mill, an attritor, and a sand mill can be used. The particle size distribution of the pigment in the pigment dispersion can be adjusted by appropriately adjusting the size of the grinding media of the dispersing machine, the filling rate of the grinding media, the dispersion treatment time, the discharge rate of the pigment dispersion, the viscosity of the pigment dispersion, etc. The viscosity of the printing ink at 25°C is preferably in the range of 50 mPa·s or more from the viewpoint of preventing sedimentation of the pigment and appropriately dispersing it, and 300 mPa·s or less from the viewpoint of work efficiency during ink production and printing. As the method for manufacturing the printing ink, for example, the method described in JP-A-2018-158986 can be used.

[0057] <Formation of ink layer> The ink layer can be formed, for example, by printing printing ink on the paper base material surface on the side opposite to the heat seal layer and then removing the volatile components. As the printing method, a flexographic printing method or a gravure printing method is preferable. For example, it is diluted with a diluting solvent to a viscosity and concentration suitable for flexographic printing or gravure printing, and is supplied to each printing unit alone or in combination and applied. Then, the ink layer can be obtained by fixing the coating film by drying with an oven or the like.

[0058] [Surface protection layer] The surface protection layer contains a styrene-acrylic copolymer resin and / or a styrene-maleic acid copolymer resin. In the surface protection layer, the total content of the styrene-acrylic copolymer resin and / or the styrene-maleic acid copolymer resin is preferably 50% by mass or more, more preferably 70% by mass or more, and particularly preferably 90% by mass or more in the total mass of the surface protection layer. When the total content is within the above range, the toughness of the surface protection layer is increased, and the releasability and puncture resistance of the packaging material are improved. Further, the film thickness of the surface protection layer is preferably 0.3 to 10 μm, more preferably 1 to 7 μm, and still more preferably 3 to 5 μm. The releasability of the above-mentioned packaging material means that when the packaging material is taken out from the wound packaging material in printing, there is no transfer of the ink layer and / or the surface protection layer to the back surface (heat seal layer) of the paper base material.

[0059] <Styrene-acrylic copolymer resin contained in the surface protection layer> The styrene-acrylic copolymer resin contained in the surface protection layer can adopt the mode of the <styrene-acrylic copolymer resin contained in the ink layer> described in the above [Ink layer].

[0060] <Styrene-maleic acid copolymer resin contained in the surface protection layer> The styrene-maleic acid copolymer resin contained in the surface protection layer can adopt the mode of the <styrene-maleic acid copolymer resin contained in the ink layer> described in the above [Ink layer].

[0061] <Other resins contained in the surface protective layer> For the other resins contained in the surface protective layer, the modes of <the other resins contained in the ink layer> described in the above [Ink layer] can be adopted. More preferably, the other resins contained in the surface protective layer contain sugar-derived resins and / or rosin resins. These resins can be used alone or in combination of two or more. The solid content mass ratio of the styrene acrylic copolymer resin and / or styrene maleic acid copolymer resin to the sugar-derived resin and / or rosin resin is preferably 80:20 to 20:80, and more preferably 60:40 to 30:70.

[0062] <Additives contained in the surface protective layer> For the additives contained in the ink layer, the modes and preferred forms of <the additives contained in the ink layer> described in the above [Ink layer] can be adopted.

[0063] <Overcoat agent> The surface protective layer is formed by an overcoat agent. The overcoat agent may contain a styrene acrylic copolymer resin and / or a styrene maleic acid copolymer resin, and further a liquid medium (organic solvent, water, etc.), additives, etc.

[0064] The solid content of the styrene acrylic copolymer resin and / or styrene maleic acid copolymer resin in the overcoat agent is preferably 25 to 100% by mass, more preferably 25 to 75% by mass, and particularly preferably 25 to 45% by mass in the total mass of the overcoat agent.

[0065] (Aqueous medium) For the aqueous medium contained in the overcoat agent, the modes and preferred forms of <the aqueous medium> described in the above [Ink layer] can be adopted.

[0066] (Organic solvent) For the organic solvent contained in the overcoat agent, the modes and preferred forms of <the organic solvent> described in the above [Ink layer] can be adopted.

[0067] <Method for manufacturing overcoat agent> The overcoat agent can be obtained by charging a resin solution in which a resin is dissolved or dispersed in an organic solvent and a solvent into a stirrer equipped with stirring blades, rotating blades, etc., and mixing and stirring them. The stirring speed is not particularly limited and can be carried out at 50 to 2000 rpm. In order to improve the handling properties, coatability, etc. of the overcoat agent, the solvent can be further added as appropriate. From the viewpoint of printing suitability, etc., the viscosity of the overcoat agent is preferably 50 to 300 mPa·s.

[0068] <Formation of surface protection layer> The surface protection layer can be formed, for example, by printing an overcoat agent on the ink layer of a packaging material provided with an ink layer on a substrate and then removing the volatile components. Examples of the printing method include the gravure printing method and the flexographic printing method. For example, the overcoat agent is diluted with a diluting solvent to a viscosity and concentration suitable for each printing method, and is supplied to each printing unit alone or in combination and applied. Then, the surface protection layer can be obtained by fixing the film by drying with an oven or the like.

[0069] [Heat seal layer] In the present invention, the heat seal layer is located on the surface opposite to the surface of the paper substrate having the printing layer. As the resin contained in the heat seal layer, ethylene vinyl acetate copolymer resin, acrylic resin, ethylene-based ionomer, urethane resin, polyethylene resin, polypropylene resin, etc. may be included. These may be used alone or in combination of two or more. Among these, the heat seal layer is preferably an ethylene vinyl acetate copolymer resin, an acrylic resin, and an ethylene-based ionomer, more preferably an ethylene vinyl acetate copolymer resin and an ethylene-based ionomer, and even more preferably an ethylene vinyl acetate copolymer resin.

[0070] <Ethylene vinyl acetate copolymer resin> Ethylene vinyl acetate copolymer resin is a copolymer composed of ethylene and vinyl acetate. The vinyl acetate content in the ethylene vinyl acetate copolymer resin is preferably 5 to 50% by mass, more preferably 10 to 40% by mass, and particularly preferably 20 to 30% by mass in 100% by mass of the ethylene vinyl acetate copolymer resin. The minimum film-forming temperature of the ethylene vinyl acetate copolymer resin is preferably 40 to 120 °C, and more preferably 60 to 100 °C. When the vinyl acetate content and the minimum film-forming temperature are within the above ranges, the heat sealability is good. The glass transition temperature of the ethylene vinyl acetate copolymer resin is preferably -60 to 20 °C, and more preferably -25 to 5 °C.

[0071] For example, the above ethylene vinyl acetate copolymer resin can be Aquatex EC series manufactured by Japan Coating Resin Co., Ltd., Sumika Flex S-201HQ, S-305, S-305HQ, S-400HQ, S-401HQ, S-408HQE, S-450HQ, S-455HQ, S-456HQ, S-460HQ, S-467HQ, S-470HQ, S-480HQ, S-510HQ, S-520HQ, S-752, S-755 manufactured by Sumitomo Chemical Co., Ltd.

[0072] <Acrylic resin> An acrylic resin is a resin containing structural units derived from (meth)acrylic monomers. The acrylic resin preferably has a carboxyl group or other acidic groups. The acid value of the acrylic resin is preferably 20 to 120 mgKOH / g, more preferably 30 to 100 mgKOH / g, and particularly preferably 40 to 80 mgKOH / g. When the acid value of the acrylic resin is 20 mgKOH / g or more, the recyclability is good, and when it is 120 mgKOH / g or less, the releasability is good. The glass transition temperature of the acrylic resin is preferably -40 to 90 °C, more preferably -30 to 70 °C, and particularly preferably -20 to 50 °C. When the glass transition temperature of the acrylic resin is within the above range, the releasability and heat sealability are good. Further, the acrylic resin preferably includes a polymer composed of (meth)acrylic monomers, a copolymer composed of (meth)acrylic monomers and vinyl compounds having acid groups, a copolymer composed of ethylene and acrylic monomers, and the like.

[0073] Examples of the (meth)acrylic monomer include alkyl ester compounds of (meth)acrylic acid such as methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, n-butyl (meth)acrylate, n-hexyl (meth)acrylate, n-octyl (meth)acrylate, decyl (meth)acrylate, lauryl (meth)acrylate, (meth)acrylic acid amide derivatives containing at least one N-substituted methylol group such as N-methylol (meth)acrylamide, aminoalkyl esters of (meth)acrylic acid such as dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, dipropylaminoethyl (meth)acrylate, dimethylaminopropyl (meth)acrylate, diethylaminopropyl (meth)acrylate, dipropylaminopropyl (meth)acrylate, mono- or diesters of (meth)acrylic acid with glycols such as diethylene glycol and dipropylene glycol, Hydroxyalkyl ester compounds of (meth)acrylic acid such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, Examples include acrylic acid, methacrylic acid, and the like. As other monomers, Styrene derivatives such as styrene and α-methylstyrene, Vinyl compounds having acid groups such as maleic acid and itaconic acid are included. From the viewpoint of heat sealability, the acrylic resin preferably has a carboxyl group and / or a hydroxyl group. When the acrylic resin has a hydroxyl group, it preferably contains a hydroxyalkyl ester compound of (meth)acrylic acid as a monomer constituting the acrylic resin.

[0074] Commercially available products may be used as the acrylic resin. For example, JONCRYL PDX7356, PDX-7326, PDX-7430 manufactured by BASF, PE-1126, JE-1113, KE1148 manufactured by Xingguang PMC, etc. can be used.

[0075] <Polyethylene-based ionomer> The polyethylene-based ionomer refers to an ionized polyethylene resin, preferably an ionized ethylene (meth)acrylic copolymer. For example, metal salts of ethylene-methacrylic acid copolymers, metal salts of ethylene-acrylic copolymers, metal salts of ethylene-urethane copolymers, metal salts of ethylene-fluorine-based polymers, etc. are preferred. Examples of the metal ions forming the salt include alkali metal ions and alkaline earth metal ions, specifically, ions of sodium, potassium, calcium, magnesium, zinc, etc. The minimum film-forming temperature of the polyethylene-based ionomer resin is preferably 20 to 100 °C, more preferably 40 to 80 °C. When the minimum film-forming temperature is within the above range, the heat sealability is good.

[0076] As the above-mentioned polyethylene-based ionomer, for example, ChemPearl S100, S111, S120, S650, S200, S300, S420, S500 manufactured by Mitsui Chemicals, Inc. can be used.

[0077] <Formation of Heat Seal Layer> The heat seal layer can be formed, for example, by printing a heat sealant on the paper base material surface on the side opposite to the surface protection layer and then drying and removing the volatile components. As the printing method, a gravure printing method or a flexographic printing method is preferable. For example, in gravure printing, it is diluted with a diluting solvent to a suitable viscosity and concentration as required, supplied to each printing unit alone or in a mixture, then coated, and the heat seal layer can be obtained by fixing the coating by drying with an oven. The resin content of the heat seal layer is preferably 80 to 100% by mass, more preferably 90 to 100% by mass in 100% by mass of the heat seal layer. When it is in the above range, the heat sealability becomes good. The film thickness of the heat seal layer is preferably 0.1 to 10 μm, still more preferably 2 to 7 μm.

[0078] <Additives Contained in Heat Seal Layer> The heat seal layer can further contain any additives such as an antifoaming agent, an emulsifier, a preservative, a plasticizer, an amide wax, a hydrocarbon wax, and a chelating crosslinking agent.

[0079] <Heat Sealant> In the present application, the heat sealant contains a heat seal resin and further contains a solvent. It may also contain the above-mentioned additives. From the viewpoint of environmental load, the heat sealant is preferably aqueous.

[0080] [Barrier Layer] The packaging material of the present invention may further have a barrier layer. The barrier layer is preferably disposed between the paper base material layer and the heat seal layer, and preferably contains an inorganic compound such as aluminum, alumina, or silica. The purity of the inorganic compound is preferably 99% or more, and more preferably 99.9% or more. The method for forming the barrier layer is not particularly limited, and an inorganic compound layer can be formed on the paper base material by a known method such as vacuum evaporation or sputtering. Also, an aluminum layer can be formed as the barrier layer by laminating an aluminum foil on the paper base material by a dry lamination method or an extrusion lamination method.

[0081] <Vacuum evaporation method> The vacuum evaporation method is a method of evaporating a metal such as aluminum at 1200 to 1500 ° C under conditions of about 10 -1 ~10 -2 Pa by high-frequency induction heating, direct current heating, or electron beam heating. The object to be evaporated can be subjected to a treatment for improving adhesion, such as corona discharge treatment on the surface, before vacuum evaporation. The thickness of the metal film formed by vacuum evaporation is preferably 10 to 300 nm from the viewpoints of barrier property, light shielding property, and economy.

[0082] <Sputtering method> The sputtering method is carried out by introducing an inert gas such as Ar and applying a voltage under conditions of about 10 -1 ~10 -2 Pa. The thickness of the metal film formed is preferably 10 to 300 nm from the viewpoints of barrier property, light shielding property, and economy.

[0083] [Adhesive layer] The packaging material of the present invention may further have an adhesive layer. The adhesive layer can be formed by applying the following adhesives. As the adhesive, a two-component reactive adhesive, an acrylic adhesive, an anchor coat agent, a molten polyolefin resin, etc. can be preferably used, and are not limited. Among them, it is preferably formed by a dry lamination method using a two-component reactive adhesive or an extrusion lamination method using an anchor coat agent and a molten polyolefin resin.

[0084] <Dry lamination method> The dry lamination method is a method of applying a two-component reactive adhesive composed of a polyol and a polyisocyanate. The adhesive is diluted with an organic solvent to an appropriate viscosity, applied to the printed surface of the obtained printed matter, dried, and then laminated by pressure bonding with a sealant. Examples of the adhesive include TM-250HV / CAT-RT86L-60, TM-550 / CAT-RT37, and TM-314 / CAT-14B manufactured by Toyo Morton Co., Ltd.

[0085] <Extrusion lamination method> The extrusion lamination method is a method of extruding a molten polyolefin resin in a film shape from a slit-shaped device called a T-die, laminating it on a base material, and bonding it to another base material. In the case of a printed matter, an anchor coat agent is usually applied in advance on the printing layer and then extrusion laminated. Also, the molten polyolefin resin can be extruded onto the printed surface of the printed matter and at the same time bonded with a sealant. As the anchor coat agent, imine-based, butadiene-based, and isocyanate-based anchor coat agents can be used. Specifically, EL-420 (imine-based), EL-452 (butadiene-based), EL-530A / B (isocyanate-based), EL-540 / CAT-RT32 (isocyanate-based), etc. manufactured by Toyo Morton Co., Ltd. can be mentioned. As the molten polyolefin resin, low-density polyethylene, polypropylene, ethylene-vinyl acetate copolymer, etc. can be used. Specifically, Novatech LD LC600A (low-density polyethylene) manufactured by Nippon Polyethylene Co., Ltd. can be mentioned.

[0086] [Packaging bag] The packaging material in the present invention is cut to a predetermined size, and the edge portions are heat-sealed in a form where the heat-sealing layers are aligned with each other to form a packaging bag. The heat-sealing temperature is preferably 50 to 250 °C, more preferably 80 to 180 °C. The heat-sealing pressure may be conditions such as 1 to 5 kg / cm 2 etc. One piece of the packaging material may be folded and the edges heat-sealed, or two or more pieces of the packaging material may be heat-sealed. Also, the packaging bag may be one in which all the openings are heat-sealed after the contents are packaged. This packaging bag can be widely used as a packaging bag for foods, pharmaceuticals, etc.

Examples

[0087] Hereinafter, the present invention will be described in detail with reference to examples, but the present invention is not limited to these examples. In the present invention, parts and % represent parts by mass and mass %, respectively, unless otherwise noted. Also, "NV." represents the mass % of the non-volatile content.

[0088] <Preparation Example 1> (Preparation of urethane resin solution PU1) While introducing nitrogen gas into a reactor equipped with a reflux cooling pipe, a dropping funnel, a gas introduction pipe, a stirring device, and a thermometer, 227.0 parts of a polyester polyol, which is a condensate of adipic acid and 3-methyl-1,5-pentanediol, 9.6 parts of PEG (polyethylene glycol with a number average molecular weight of 2000), 30.1 parts of 2,2-dimethylolpropanoic acid (DMPA), and 250 parts of methyl ethyl ketone (MEK) were mixed, and 90.6 parts of isophorone diisocyanate (IPDI) was added dropwise over 1 hour while stirring, and reacted at 80 °C for 4 hours to obtain a terminal isocyanate prepolymer, and a terminal isocyanate prepolymer solution was obtained. To the obtained terminal isocyanate prepolymer solution, a mixture of 2.7 parts of 2-aminoethylethanolamine (AEA) and 150 parts of isopropanol (IPA) was gradually added at room temperature and reacted at 40 °C for 2 hours to obtain a solvent-type polyurethane resin solution. Next, 38.1 parts of 10% aqueous ammonia and 801.4 parts of ion-exchanged water were gradually added to the solvent-type polyurethane resin solution for neutralization to make it water-soluble, and further 0.5 part of an antifoaming agent was added. After distilling off MEK and IPA under reduced pressure, water was added to adjust the solid content, and a urethane resin solution PU1 with a solid content of 28% and a weight average molecular weight of 38,000 was obtained.

[0089] (Paper substrates S1 to S7 containing a sizing agent) Basis weight 65 g / m 2 Using a tabletop size press machine (manufactured by Kumagai Riki Kogyo Co., Ltd.) capable of simultaneously coating both sides of a paper substrate S with an equal amount of coating on both sides, a coating agent containing a sizing agent was coated so that the total dry coating amount on both sides would be the value described in Table 3, and dried in a 60 °C oven to obtain the following paper substrates S1 to S7 containing a sizing agent. S1a to S1e: Paper substrates containing a sizing agent of rosin resin (manufactured by Arakawa Chemical Industries, Ltd., Polymeron 351T, solid content 20%) S2: Paper substrate containing a sizing agent of alkenyl succinate (manufactured by Arakawa Industries, Ltd., SP864, solid content 20%) S3: Paper substrate containing a sizing agent of alkyl ketene dimer (manufactured by Starlight PMC Co., Ltd., SE2360, solid content 20%) S4: Paper substrate containing a sizing agent of polyvinyl alcohol resin (manufactured by Nippon Gosei Chemical Industry Co., Ltd., Gosenal T-350, solid content 20%) S5: Paper substrate containing a sizing agent of starch resin (manufactured by Nippon Corn Starch Co., Ltd., SK-20, solid content 20%) S6: Paper substrate containing a sizing agent of urethane resin (PU1) S7: Paper substrate without a sizing agent

[0090] <Production Example 1> Production of printing ink K1 A mixture of 15 parts of water, 15 parts of Pigment Blue 15:3 (manufactured by Toyo Color Co., Ltd., blue pigment C.I. Pigment Blue 15:3 (Lionol Blue FG7330)), 2 parts of PEG-PPG (copolymer resin of polyethylene glycol (PEG) and polypropylene glycol (PPG), weight average molecular weight 2800, PEG:PPG = 40:60, solid content 100%), and 1 part of acetylene glycol (Surfinol SE manufactured by Nissin Chemical Industry Co., Ltd., solid content 80%) was kneaded and dispersed in a bead mill, and then 32.3 parts of styrene-acrylic copolymer resin (acid value 50 mgKOH / g, glass transition temperature 40 °C, solid content 50% by mass), 32.3 parts of sugar-derived resin (styrene-acrylic resin emulsion with an average particle diameter of 150 μm containing 28% by mass of polysaccharide-derived components, hydroxyl value 300 mgKOH / g, acid value 50 mgKOH / g, solid content 50% by mass), 2 parts of Chem Pearl W400 (manufactured by Mitsui Chemicals, polyethylene wax, penetration: 3, density: 920 Kg / m 3 , particle size: 4 μm), and 0.4 part of BYK-024 (defoaming agent manufactured by BYK) were added and stirred and mixed to obtain printing ink K1.

[0091] <Production Examples 2 to 15, Comparative Production Examples 1 and 2> Production of printing inks K2 to 17 Printing inks K2 to 17 were obtained in the same manner as in Production Example 1 except that the raw materials and compounding ratios described in Table 2 were used. The abbreviations in the table represent the following. Styrene-maleic acid copolymer resin: acid value 150 mgKOH / g, glass transition temperature 80 °C, solid content 50% by mass Rosin resin: (Rosin resin emulsion, glass transition temperature 100 °C, hydroxyl value 0 mgKOH / g, acid value 120 mgKOH / g, solid content 50 mass%)

[0092] <Production Example 16> Production of Overcoat Agent V1 48.8 parts of styrene-acrylic copolymer resin (acid value 50 mgKOH / g, glass transition temperature 40 °C, solid content 50 mass%), 48.8 parts of sugar-derived resin (styrene-acrylic resin emulsion with an average particle diameter of 150 μm containing 28 mass% of polysaccharide-derived components, hydroxyl value 300 mgKOH / g, acid value 50 mgKOH / g, solid content 50 mass%), 2 parts of Chem Pearl W400 (manufactured by Mitsui Chemicals, polyethylene wax, penetration: 3, density: 920 Kg / m 3 , particle size: 4 μm), 0.4 part of BYK-024 (manufactured by BYK, defoaming agent) were stirred and mixed to obtain Overcoat Agent V1.

[0093] <Production Examples 17 to 30, Comparative Production Examples 3 and 4> Production of Overcoat Agents V1 to V17 Overcoat Agents V2 to V17 were obtained in the same manner as in Production Example 16, except that the raw materials and compounding ratios described in Table 3 were used.

[0094]

Table 1

[0095]

Table 2

[0096] (Heat Seal Agents H1 to H4) H1: Heat seal agent containing ethylene-vinyl acetate copolymer resin (manufactured by Japan Coating Resin, Aquatex MC3800, minimum film-forming temperature: 100 °C, solid content 50 mass%) H2: Heat seal agent containing ethylene-acrylic resin (acid value 100 mgKOH / g, glass transition temperature 20 °C, solid content 48 mass%) H3: Heat sealant containing ethylene-based ionomer (manufactured by Mitsui Chemicals, Chem Pearl S100, minimum film-forming temperature: 65 °C, solid content 27 mass%) H4: Heat sealant containing urethane resin (PU1)

[0097] <Example 1> (Manufacture of laminate P1) Next, using a gravure printing machine equipped with a gravure plate with a plate depth of 50 μm, heat sealant H1 was printed on paper substrate S1 containing a sizing agent under the conditions of a printing speed of 50 m / min and an in-line oven of 70 °C to obtain an intermediate laminate p1 having a structure of a heat seal layer / paper substrate containing a sizing agent. On the opposite side of the heat seal layer of the substrate in the intermediate laminate p1, using a small flexo printer (flexographic printer) equipped with an anilox roll of 250 lines / inch and a solid plate made of photosensitive resin, after printing printing ink K1 under the condition of a printing speed of 50 m / min, it was dried with a 1200W dryer for 10 seconds to form an ink layer. On the said ink layer, using a small flexo printer (flexographic printer) equipped with an anilox roll of 200 lines / inch and a solid plate made of photosensitive resin, after printing overcoat agent V1 under the condition of a printing speed of 50 m / min, it was dried under the conditions of 25 °C for 12 hours to obtain a packaging material P1 having a structure of a heat seal layer / paper substrate containing a sizing agent / ink layer / surface protection layer.

[0098] <Examples 2 to 50, Comparative Examples 1 to 3> (Manufacture of packaging materials P2 to 50, P'1 to 3) Except for using the heat sealant, paper substrate containing a sizing agent, printing ink, and overcoat agent shown in Table 3, packaging materials P2 to 22 and P'1 to 3 having the same configuration were produced in the same procedure as the production of the above packaging material. In Examples 43 to 46, the number of lines of the anilox roll was adjusted to change the film thickness of the surface protection layer. In Comparative Example 1, the same anilox as in Example 1 was used, but since it does not have an HS layer, the penetration of the printing layer into the paper is large and the film thickness is thin.

[0099] [Evaluation of packaging material] For the packaging materials P1 to P22 and P'1 to P'3 obtained in Examples 1 to 22 and Comparative Examples 1 to 3, the evaluations described below were conducted. The results are shown in Table 3.

[0100] <Water-resistant friction resistance> The obtained packaging materials were cut into pieces of 25 mm × 150 mm in size, and the water-resistant friction resistance was evaluated using a Kagaku-shin-kou type friction fastness tester manufactured by Tester Sangyo Co., Ltd. according to the following criteria. Note that A, B, and C are within the range where there are no practical problems. <Test conditions> Load: 200 g, number of reciprocations: 2 times, rubbing paper: Kanakin cloth with 5 drops of water dripped <Evaluation criteria> A. The printing layer is not removed, and the exposed area ratio of the base paper is less than 1%. B. Ink adheres slightly to the rubbing paper. The printing layer is slightly removed, and the exposed area ratio of the base paper is 1% or more and less than 10%. C. Ink adheres thinly over the entire rubbing paper. The printing layer is slightly removed, and the exposed area ratio of the base paper is 10% or more and less than 20%. D. Ink adheres thickly over the entire rubbing paper. The printing layer is almost completely removed, and the exposed area ratio of the base paper is 20% or more.

[0101] <Surface glossiness> The surface of the printing layer of the obtained packaging materials was measured for the 60-degree gloss value using a Micro-TRI-gross meter manufactured by BYK-Gardner. At the same time, visual observation was carried out and evaluated according to the following criteria. Note that the gloss value measurement was carried out in accordance with JIS Z8741:1997, 60-degree specular gloss (Gs(60)). Note that A, B, and C are within the range where there are no practical problems. <Evaluation criteria> A. The gloss value is 40 or more. B. The gloss value is 25 or more and less than 40. C. Those with a slightly matte appearance visually. D. Those with a strong matte appearance visually.

[0102] <Release property> The obtained packaging material was cut into two pieces with a size of 40 mm square. The heat-sealing layer and the surface protection layer of the cut packaging material were overlapped, and using a small hot press machine H30-10D manufactured by AS ONE Corporation, at a temperature of 40 °C and a load of 100 Kg / cm 2 (The load means a significantly excessive condition.) Pressurization was carried out under these conditions. After standing in that state for 12 hours, the two printed materials stacked together were peeled off, and the peeling state of the printed layer was visually observed and evaluated according to the following criteria. Note that A, B, and C are within the range where there are no practical problems. 《Evaluation Criteria》 A. The transfer amount of the printed layer to the back surface of the base paper is less than 1 area%. B. The transfer amount of the printed layer to the back surface of the base paper is 1 area% or more and less than 10 area%. C. The transfer amount of the printed layer to the back surface of the base paper is 10 area% or more and less than 20 area%. D. The transfer amount of the printed layer to the back surface of the base paper is 20 area% or more.

[0103] <Impact Resistance> The obtained laminate was cut into a 70 mm square, and using a method compliant with JIS 1707, a test was carried out under the following test conditions and evaluated according to the following criteria. Note that A, B, and C are within the range where there are no practical problems. 《Puncturing Test Conditions》 Puncturing speed: 50 mm / min, diameter of the needle: 1 mm, Puncturing surface of the needle: the printed layer surface of the laminate 《Evaluation Criteria》 A. The puncturing strength is 15 N or more. B. The puncturing strength is 13 N or more and less than 15 N. C. The puncturing strength is 5 N or more and less than 13 N. D. The puncturing strength is less than 5 N.

[0104] <Heat Sealability> The obtained packaging material was cut into a size of 15 mm × 100 mm, bent so that the heat-sealing layer surfaces overlapped each other, heat-sealed under the following apparatus and conditions, and the unsealed both ends were fixed to a small tensile tester to evaluate the heat-sealing strength. Note that A, B, and C are within the range where there are no practical problems. 《Heat Sealing Conditions》 Apparatus: Heat Sealing Tester manufactured by Tester Sangyo Co., Ltd., Seal width: 10 mm from the bent part Heater temperature: 160 °C, Seal pressure: 2 kg / cm 2 , Seal time: 1 sec 《Heat Sealing Strength Measurement Conditions》 Apparatus: Small Tensile Tester (Model; IM-20) manufactured by Inesco Co., Ltd., Test piece width: 15 mm Peeling mode: 90° peeling, Tensile speed: 300 mm / min 《Evaluation Criteria》 A. The heat sealing strength is 5.0 N or more. B. The heat sealing strength is 3.5 N or more and less than 5.0 N. C. The heat sealing strength is 1.0 N or more and less than 3.5 N. D. The heat sealing strength is less than 1.0 N.

[0105]

Table 3

[0106]

Table 3

[0107] According to the present invention, a packaging material excellent in water friction resistance, surface gloss, releasability, puncture resistance, and heat sealability can be provided. In particular, in Comparative Example 1 without a heat seal layer, the heat sealability did not meet the standard. In Comparative Example 2 where the paper base material did not contain a sizing agent, the water friction resistance, surface gloss, and releasability did not meet the standard. In Comparative Example 3 where the printing layer did not contain a styrene-acrylic copolymer resin and / or a styrene-maleic acid copolymer resin, the water friction resistance, surface gloss, releasability, and puncture resistance did not meet the standard.

Claims

1. A packaging material having a heat-sealing layer, a paper substrate containing a sizing agent, and a printing layer in that order, wherein the paper substrate is in contact with the printing layer, and the printing layer contains a styrene-acrylic copolymer resin and / or a styrene-maleic acid copolymer resin.

2. The packaging material according to claim 1, wherein the sizing agent contains at least one selected from the group consisting of rosin resin, alkenyl succinate, alkyl ketene dimer, polyvinyl alcohol resin, and starch resin.

3. The packaging material according to claim 1 or 2, wherein the gloss value measured by JIS Z 8741 of the printing layer is 15 to 60.

4. The packaging material according to claim 1 or 2, wherein the printing layer further contains a sugar-derived resin and / or a rosin resin.

5. The packaging material according to claim 1 or 2, wherein the printing layer contains an ink layer and / or a surface protection layer.

6. The packaging material according to claim 1 or 2, wherein the heat-sealing layer contains at least one selected from the group consisting of ethylene-vinyl acetate copolymer resin, acrylic resin, and ethylene-based ionomer.

7. The content per unit area of the sizing agent in the paper substrate is 0.3 to 1.0 g / m ２ The packaging material according to claim 1 or 2, wherein the content is as described above.

8. A method for manufacturing a packaging material having a heat-sealing layer, a paper substrate containing a sizing agent, and a printing layer, Step 1 of papermaking a mixture of plant fibers and a sizing agent to obtain a paper substrate containing the sizing agent, and at least one of Step 2 of coating a coating agent containing a sizing agent on the paper substrate to obtain a paper substrate containing the sizing agent, Step 3 of printing a printing ink or an overcoat agent containing a styrene-acrylic copolymer resin and / or a styrene-maleic acid copolymer resin on one surface of the paper substrate containing the sizing agent to form a printing layer, A method for manufacturing a packaging material, including Step 4 of coating a heat-sealing agent on the other surface of the paper substrate to form a heat-sealing layer.

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