Base paper for metallized paper, metallized paper, packaging bag, and method for manufacturing base paper for metallized paper

Abstract

An object of the present invention is to provide a metal-deposited paper having excellent barrier properties and excellent adhesion between layers, a base paper for metal-deposited paper, a metal-deposited paper and a packaging bag using the base paper for metal-deposited paper, and a method for manufacturing the base paper for metal-deposited paper. The base paper for metallized paper of the present invention is a base paper for metallized paper having a clay coating layer and two or more resin layers, in that order, on at least one surface of a paper substrate, and the two or more resin layers each have a thickness of 0.1 μm or more and 4 μm or less, and a total thickness of 0.2 μm or more and 5 μm or less.

Description

[Technical field]

[0001] The present invention relates to a base paper for metallized paper, metallized paper, a packaging bag, and a method for manufacturing a base paper for metallized paper. [Background technology]

[0002] Conventionally, packaging materials having a paper base material imparted with water vapor barrier properties that provide a barrier against water vapor, gas barrier properties that provide a barrier against gases other than water vapor, and in particular, oxygen barrier properties that provide a barrier against oxygen, have been used in packaging foods, medical products, electronic components, and the like to prevent deterioration of the contents.

[0003] Metal-deposited paper is made by forming a metal-deposited layer on a paper base material. Taking advantage of its glossy appearance, it is widely used for label paper with excellent design for alcoholic beverages, soft drinks, etc., and wrapping paper for confectionery.

[0004] For example, Japanese Patent No. 6958757 discloses a base paper for metallized paper having a clay coat layer and a resin layer, in that order, on at least one side of a paper substrate, for forming a metallized layer by vapor deposition, with the aim of providing a base paper for metallized paper that can provide metallized paper with excellent barrier properties, wherein the surface of the resin layer has a wetting tension of 50 mN / m or more as measured in accordance with JIS K 6768:1999 and a print-surf surface roughness of 2.5 μm or less as measured in accordance with JIS P 8151:2004. Summary of the Invention

[0005] Metal-deposited paper used as a packaging material for food is required to have further improved barrier properties (oxygen barrier property, water vapor barrier property) from the viewpoint of protecting the flavor of food. Through studies by the present inventors, it has been found that there is room for further improvement in the barrier properties of metal-deposited paper using the base paper for metal-deposited paper described in Japanese Patent No. 6958757. In addition, in order to suppress deterioration due to use of packaging bags made of metal-deposited paper, it is desired that the base paper for metal-deposited paper has excellent adhesion between the layers constituting the base paper for metal-deposited paper. Thus, an object of the present invention is to provide a metal-deposited paper having excellent barrier properties, and to provide a base paper for metal-deposited paper having excellent adhesion between the layers, a metal-deposited paper and a packaging bag using the base paper for metal-deposited paper, and a method for manufacturing the base paper for metal-deposited paper.

[0006] The inventors discovered that the above problem can be solved by making the resin layer constituting the base paper for metallized paper two or more layers and setting the thickness of each layer within a specific range, and thus completed the present invention.

[0007] That is, the present invention provides the following: <1> ~ <14> Regarding. <1> A base paper for metallized paper having a clay coating layer and two or more resin layers in this order on at least one surface of a paper substrate, A base paper for metallized paper, in which the thickness of each of the two or more resin layers is 0.1 μm or more and 4.0 μm or less, and the total thickness is 0.2 μm or more and 5.0 μm or less. <2> The 75° specular gloss of the surface having two or more resin layers is 75.0% or more as measured in accordance with JIS P 8142:2005. <1> 2. A base paper for metallized paper according to claim 1. <3> Each resin layer contains a resin having a glass transition temperature of 50° C. or higher. <1> or <2> 2. A base paper for metallized paper according to claim 1. <4> Each resin layer contains a water-suspendable polymer, and the water-suspendable polymer contains one or more resins selected from the group consisting of polyurethane-based resins and polyester-based resins. <1> ~ <3> 10. A base paper for metallized paper according to claim 9. <5> In cases where there are two or more resin layers, the outermost layer is thicker than the innermost layer. <1> ~ <4> 10. A base paper for metallized paper according to claim 9. <6> <1> ~ <5> 2. A metal-deposited paper having a metal-deposited layer on two or more resin layers of the base paper for metal-deposited paper described in any one of 1 to 11. <7> A heat seal layer is provided on the deposition layer. <6> The metallized paper described in <8> An overcoat layer is provided between the deposition layer and the heat seal layer. <7> The metallized paper described in <9> The overcoat layer contains at least one resin selected from the group consisting of a polyurethane-based resin, a polyester-based resin, and a vinyl alcohol-based resin. <8> The metallized paper described in <10> The 20° specular gloss of the heat seal layer surface measured in accordance with JIS P 8142:2005 is 40.0% or more; <7> ~ <9> 13. The metallized paper according to claim 12, <11> Oxygen permeability at 23℃ and 50% RH is 0.30mL / (m 2 ·day·atm) or less, and the water vapor permeability at 40°C and 90% RH is 0.60g / (m 2 ·day) or less, <6> ~ <10> 13. The metallized paper according to claim 12, <12> A pigment coating layer is provided on the opposite side to the surface having the deposition layer. <6> ~ <11> 13. The metallized paper according to claim 12, <13> <6> ~ <12> A packaging bag made using the metallized paper described in any one of the above. <14> The method comprises the following steps 1 and 2 in this order: <1> ~ <5> 10. A method for producing a base paper for metallized paper according to any one of the above items. Step 1: A step of forming a clay coat layer by applying a coating liquid for a clay coat layer containing an inorganic pigment and a binder to at least one surface of a paper substrate and drying the coating liquid. Step 2: A step of forming two or more resin layers by applying a resin layer coating liquid containing a water-dispersible polymer onto the clay coat layer and drying the coating liquid. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] The base paper for metallized paper of this embodiment has a clay coat layer and two or more resin layers in this order on at least one side of a paper substrate, and the two or more resin layers each have a thickness of 0.1 μm to 4.0 μm and a total thickness of 0.2 μm to 5.0 μm. The base paper for metallized paper of this embodiment can provide metallized paper with excellent barrier properties, and also has excellent adhesion between each layer (specifically, between the resin layers and between the resin layer, clay coat layer and paper substrate). The mechanism by which this effect is achieved is unknown, but is presumed to be as follows.

[0009] The base paper for metallized paper of this embodiment has two or more resin layers, each of which has a thickness of 0.1 μm to 4.0 μm and a total thickness of 0.2 μm to 5.0 μm, thereby ensuring the flexibility of the resin layer and maintaining the adhesion between the resin layers while maintaining the adhesion between the paper base material and the resin layer. Furthermore, the base paper for metallized paper of this embodiment has two or more resin layers on a clay coat layer, each of which has a thickness of 0.1 μm to 4.0 μm and a total thickness of 0.2 μm to 5.0 μm, thereby reducing fine irregularities on the surface of the resin layer and increasing the glossiness, thereby forming a metallized layer with a uniform thickness on the resin layer, and the metallized paper manufactured using the base paper for metallized paper can exhibit excellent barrier properties. It should be noted that the above mechanism is merely speculation, and the present invention is not limited thereto.

[0010] The base paper for metallized paper of this embodiment has excellent adhesion between resin layers and between the resin layer, clay coat layer and paper substrate, and therefore, it is considered that the metallized paper obtained using this base paper for metallized paper can suppress the decrease in barrier properties caused by peeling between the resin layers and / or between the resin layer and the paper substrate during processing, bag making, and use of the packaging bag made from the metallized paper. In addition, due to the excellent adhesion, it is considered that the packaging bag can maintain its easy-openability while preventing opening due to the peeling, and can maintain its sealability during bag making.

[0011] The configuration and physical properties of the base paper for metallized paper of this embodiment will be described in more detail below. In this specification, the numerical range represented by "X to Y" means a numerical range including X as the lower limit and Y as the upper limit. When the numerical range is described in stages, the upper and lower limits of each numerical range can be arbitrarily combined. In addition, "(meth)acrylic" is a generic term including both acrylic and methacrylic.

[0012] The base paper for metallized paper of this embodiment may have a clay coat layer and two or more resin layers in this order on one side of the paper substrate, or may have a clay coat layer and two or more resin layers in this order on both sides of the paper substrate. From the viewpoint of production efficiency, it is preferable to have a clay coat layer and two or more resin layers in this order on one side of the paper substrate, and in this case, a pigment coating layer described later may be provided on the other side of the paper substrate.

[0013] <Paper base material> The pulp constituting the paper base material in this embodiment is preferably mainly composed of plant-derived pulp, and more preferably mainly composed of wood pulp. Examples of wood pulp include hardwood pulp and softwood pulp. Examples of non-wood pulp include cotton pulp, hemp pulp, kenaf pulp, bamboo pulp, etc. Materials other than pulp fibers, such as synthetic fibers such as rayon fibers and nylon fibers, may also be blended as secondary paper materials as long as they do not impair the effects of the present invention.

[0014] The proportion of hardwood pulp in the pulp constituting the paper base material is preferably 65% ​​by mass or more, more preferably 80% by mass or more, even more preferably 90% by mass or more, and even more preferably 95% by mass or more, and may be 100% by mass. When the proportion of hardwood pulp in the pulp constituting the paper base material is within the above range, the formation of the metallized paper and its suitability for bag making are excellent.

[0015] Specific examples of the paper substrate used for the base paper for metallized paper in this embodiment include bleached kraft paper, unbleached kraft paper, fine paper, paperboard, liner paper, coated paper, one-sided glossy bleached paper, glassine paper, graphene paper, etc. Among these, bleached kraft paper, unbleached kraft paper, fine paper, and one-sided glossy bleached paper are preferred, and one-sided glossy bleached paper is more preferred.

[0016] (Stockigt size) The Stockigt sizing degree of the paper base material is not particularly limited, but from the viewpoint of improving the barrier properties, it is preferable that the Stockigt sizing degree according to JIS P 8122:2004 is 1 second or more on at least the side on which the resin layer described later is provided. There is no particular upper limit, but it is preferably 100 seconds or less, more preferably 30 seconds or less. The Stockigt sizing degree of the paper base material can be controlled by the type and content of the internal sizing agent, the type of pulp, smoothing treatment, etc.

[0017] Examples of the internal sizing agent include rosin-based, alkyl ketene dimer-based, alkenyl succinic anhydride-based, styrene-unsaturated carboxylic acid-based, higher fatty acid-based, petroleum resin-based, etc. The content of the internal sizing agent is not particularly limited, but is preferably 0 to 3 parts by mass relative to 100 parts by mass of the pulp of the paper base material.

[0018] In addition to the internal sizing agent, other known internal additives may be added to the paper base material, such as fillers, paper strength agents, retention aids, pH adjusters, drainage improvers, water resistance agents, softeners, antistatic agents, defoamers, slime control agents, dyes, and pigments.

[0019] Examples of fillers include titanium dioxide, kaolin, talc, calcium carbonate (heavy calcium carbonate, light calcium carbonate), calcium sulfite, gypsum, calcined kaolin, white carbon, amorphous silica, delaminated kaolin, diatomaceous earth, magnesium carbonate, aluminum hydroxide, calcium hydroxide, magnesium hydroxide, zinc hydroxide, and the like.

[0020] The paper base material is obtained by making paper from a papermaking raw material containing a pulp slurry as a main component. The pulp slurry is obtained from wood or non-wood raw material chips through processes such as cooking, washing, bleaching, etc. There are no particular limitations on the methods used in the cooking, washing, bleaching, etc. The pulp slurry obtained through these processes is further beaten in the presence of water.

[0021] In the papermaking of the paper base material, a known wet papermaking machine can be appropriately selected and used. Examples of the papermaking machine include a fourdrinier papermaking machine, a gap former type papermaking machine, a cylinder papermaking machine, and a short wire papermaking machine. The paper layer formed by the papermaking machine is preferably conveyed, for example, by a felt and dried by a dryer. A multi-stage cylinder dryer may be used as a pre-dryer before drying by the dryer.

[0022] The paper base material obtained as described above may be subjected to a surface treatment using a calendar to uniformize the paper thickness and gloss profile. A known calendaring machine can be appropriately selected and used for the calendaring.

[0023] (Basic weight) The basis weight of the paper substrate is not particularly limited, but is preferably 20 g / m 2 More than 500g / m 2 More preferably, it is 30 g / m or less. 2 More preferably, 40 g / m 2 More preferably, it is 400 g / m or more. 2 More preferably, 200 g / m 2 More preferably, 100 g / m 2 The basis weight of the paper base material is preferably equal to or more than the lower limit from the viewpoint of strength when used as a packaging bag, and is preferably equal to or less than the upper limit from the viewpoint of economy and ease of production. The basis weight of the paper base material is measured in accordance with JIS P 8124:2011.

[0024] (Thickness) The thickness of the paper substrate is not particularly limited, but is preferably 20 μm or more and 500 μm or less, more preferably 30 μm or more, even more preferably 40 μm or more, and more preferably 400 μm or less, even more preferably 200 μm or less, and even more preferably 100 μm or less. From the viewpoint of strength when used as a packaging bag, the thickness of the paper substrate is preferably the above lower limit value or more, and from the viewpoint of economy and ease of production, it is preferably the above upper limit value or less. The thickness of the paper substrate is measured in accordance with JIS P 8118:2014.

[0025] (density) The density of the paper substrate is not particularly limited, but from the viewpoint of moldability, it is preferably 0.5 g / cm 3 More than 1.2g / cm 3 More preferably, it is 0.6 g / cm or less. 3 More preferably, it is 1.0 g / cm or more. 3 The density of the paper base material is calculated from the basis weight and thickness of the paper base material measured by the above-mentioned method.

[0026] (Oken type smoothness) From the viewpoint of obtaining a vapor deposition layer with a uniform thickness, the paper substrate has an Oken smoothness of at least 5 seconds, more preferably 10 seconds or more, on at least the surface on which the vapor deposition layer is to be formed. The upper limit is not particularly limited, but is preferably, for example, 1000 seconds or less. The Oken smoothness of the paper substrate is measured in accordance with JIS P 8155:2010.

[0027] <Clay court layer> The base paper for metallized paper of this embodiment has a clay coat layer between the paper substrate and a resin layer described later. This forms a resin layer that seals the paper substrate and has excellent surface gloss. It is believed that the higher the gloss of the resin layer surface, the more the fine irregularities on the resin layer surface are suppressed, and as a result, a metallized layer with a uniform thickness can be formed on the resin layer, improving the barrier properties of the metallized paper.

[0028] The clay coat layer preferably contains an inorganic pigment and a binder, and more preferably is mainly composed of an inorganic pigment and a binder. The phrase "the clay coat layer is mainly composed of an inorganic pigment and a binder" means that the total content of the inorganic pigment and the binder in the clay coat layer is, for example, 50% by mass or more, preferably 60% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, even more preferably 90% by mass or more, and particularly preferably 95% by mass or more. The upper limit is not particularly limited, but is 100% by mass or less. The clay coat layer may further contain other components in addition to the inorganic pigment and the binder.

[0029] (Inorganic pigments) The inorganic pigment contained in the clay coat layer is not particularly limited, but includes kaolin, talc, mica, etc., and preferably contains kaolin. In order to increase the gloss of the resin layer surface, it is preferable to suppress the unevenness of the clay coat layer surface, and for this purpose, it is preferable to use a plate-shaped inorganic pigment. The inorganic pigment may be used alone or in combination of two or more types. The content of the inorganic pigment in the clay coat layer is preferably 30% by mass or more and 90% by mass or less, more preferably 40% by mass or more, even more preferably 50% by mass or more, and more preferably 80% by mass or less, even more preferably 70% by mass or less.

[0030] Aspect ratio The aspect ratio of the inorganic pigment is preferably 50 or less from the viewpoint of suppressing fine irregularities on the resin layer surface, forming a vapor deposition layer with a uniform thickness on the resin layer, enhancing the barrier properties, and from the viewpoint of finely dispersing the inorganic pigment in the clay coat layer and improving the disintegration properties of the base paper for vapor deposition paper during recovery. The lower limit is not particularly limited, but is preferably 1 or more. The aspect ratio can be measured by observation with an electron microscope or X-ray diffraction measurement.

[0031] ≪Average particle size≫ The average particle size of the inorganic pigment is preferably 5 μm or less, more preferably 3 μm or less, and even more preferably 1 μm or less, from the viewpoint of suppressing fine irregularities on the resin layer surface, forming a vapor deposition layer with a uniform thickness on the resin layer, enhancing the barrier properties, and from the viewpoint of finely dispersing the inorganic pigment in the clay coat layer. The lower limit is not particularly limited, but is preferably 0.05 μm or more. The average particle size means the median diameter (d50) measured by laser diffraction scattering type particle size distribution measurement.

[0032] (binder) The binder contained in the clay coat layer is not particularly limited, and examples thereof include styrene-butadiene resins; (meth)acrylic (co)polymers; styrene-(meth)acrylic resins; olefin-unsaturated carboxylic acid copolymers such as ethylene-acrylic acid copolymers and ethylene-methacrylic acid copolymers; and polylactic acid. The binder may be used alone or in combination of two or more. The binder preferably contains one or more selected from the group consisting of styrene-butadiene resins, styrene-(meth)acrylic resins, olefin-unsaturated carboxylic acid copolymers, and polylactic acid, more preferably contains one or more selected from the group consisting of styrene-(meth)acrylic resins, ethylene-(meth)acrylic acid copolymers, and polylactic acid, even more preferably contains one or more selected from styrene-acrylic resins, ethylene-acrylic acid copolymers, and polylactic acid, and even more preferably contains styrene-acrylic resins.

[0033] The (meth)acrylic (co)polymer is a (co)polymer of one or more monomers selected from (meth)acrylic acid and (meth)acrylic acid esters. The (meth)acrylic acid ester is not particularly limited, but is preferably an alkyl ester of (meth)acrylic acid having 1 to 12 carbon atoms.

[0034] The styrene-(meth)acrylic resin is a copolymer of styrene and a monomer containing at least one selected from (meth)acrylic acid and (meth)acrylic acid ester, preferably a styrene-acrylic resin, more preferably a styrene-acrylic acid copolymer or a styrene-acrylic acid ester copolymer. As for the above monomer, an example of a monomer other than (meth)acrylic acid and (meth)acrylic acid ester is acrylonitrile. As the styrene-(meth)acrylic resin, a commercially available product may be used, specifically, Acronal S504 manufactured by BASF is exemplified.

[0035] The binder content in the clay coat layer is preferably 10% by mass or more and 70% by mass or less, more preferably 20% by mass or more, even more preferably 30% by mass or more, and more preferably 60% by mass or less, even more preferably 50% by mass or less.

[0036] (Other Ingredients) Components other than the inorganic pigment and the binder that may be contained in the clay coat layer include adhesives, dispersants, thickeners, water retention agents, defoamers, water resistance agents, colorants, surfactants, etc. Adhesives include proteins such as casein, soy protein, synthetic protein, etc. Starches such as oxidized starch, cationic starch, urea phosphate esterified starch, etherified starch such as hydroxyethyl etherified starch, dextrin, etc. Cellulose derivatives such as carboxymethyl cellulose, hydroxyethyl cellulose, hydroxymethyl cellulose, etc.

[0037] The coating amount of the clay coating layer is not particularly limited, but is preferably 5 g / m2 in terms of solid content. 2 More than 30g / m 2 More preferably, it is 7 g / m or less. 2 More preferably, it is 20 g / m or more. 2 The following is the result.

[0038] The thickness of the clay coat layer is not particularly limited, but is preferably 1 μm or more and 20 μm or less, more preferably 3 μm or more, even more preferably 5 μm or more, and more preferably 15 μm or less, even more preferably 10 μm or less. The thickness of the clay coat layer is measured in accordance with JIS P 8118:2014 by measuring the thickness before and after forming the clay coat layer on the paper base material and calculating the difference.

[0039] The method for forming the clay coat layer is not particularly limited, but it is preferable to form the clay coat layer by applying a dispersion containing an inorganic pigment and a resin binder onto a paper substrate and drying it. The dispersion containing an inorganic pigment and a resin binder is preferably one that uses an aqueous medium such as an aqueous dispersion as a solvent.

[0040] <Resin layer> The base paper for metallized paper of this embodiment has two or more resin layers arranged on a clay coat layer. By providing two or more resin layers, the adhesion between the metallized layer of the metallized paper and the paper base material is improved, and the barrier properties are improved. In addition, since the two or more resin layers have oxygen barrier properties and water vapor barrier properties, they also have the function of improving the barrier properties when made into metallized paper.

[0041] The two or more resin layers each have a thickness of 0.1 μm or more and 4.0 μm or less, and the total thickness is 0.2 μm or more and 5.0 μm or less. The number of resin layers is not particularly limited and can be, for example, 2 to 6 layers, preferably 2 to 5 layers, more preferably 2 to 4 layers, and from the viewpoints of productivity and barrier properties, still more preferably 2 or 3 layers.

[0042] From the viewpoints of adhesion between the resin layers and between the resin layer and the paper substrate, and barrier properties, the thickness of each of the two or more resin layers is preferably 0.2 μm or more and 3.6 μm or less, more preferably 0.3 μm or more, even more preferably 0.4 μm or more, and more preferably 3.2 μm or less, even more preferably 2.8 μm or less, and even more preferably 2.4 μm or less.

[0043] From the viewpoint of ease of forming the resin layers, it is preferable that the outermost layer (the resin layer furthest from the paper base material) of two or more resin layers is thicker than the innermost layer (the resin layer in contact with the paper base material), and it is preferable that the thickness increases from the innermost layer to the outermost layer.

[0044] From the viewpoint of adhesion between the resin layers and between the resin layer and the paper substrate, and barrier properties, the total thickness of two or more resin layers is preferably 0.3 μm or more and 4.6 μm or less, more preferably 0.6 μm or more, even more preferably 0.9 μm or more, and more preferably 4.2 μm or less, even more preferably 3.8 μm or less, and even more preferably 3.2 μm or less.

[0045] The coating amount per layer of two or more resin layers is preferably 0.2 g / m2 in terms of solid content from the viewpoints of adhesion between the resin layers and between the resin layer and the paper substrate, and barrier properties. 2 More than 3.6g / m 2 More preferably, it is 0.3 g / m or less. 2 More preferably, 0.4 g / m 2 More preferably, it is 3.2 g / m or more. 2 Less than 2.8 g / m, more preferably 2.8 g / m 2 Less than 2.4 g / m 2 The method for forming each resin layer is not particularly limited, but it is preferable to coat an aqueous medium such as an aqueous solution or an aqueous dispersion of a water-dispersible polymer according to the number of layers, and then dry the layers.

[0046] Each resin layer preferably contains a resin having a glass transition temperature of 50° C. or higher. By forming each resin layer using a resin having a glass transition temperature of 50° C. or higher, the glossiness of the resin layer surface can be maintained even when exposed to high-temperature steam during deposition, that is, fine irregularities on the resin layer surface can be suppressed, and a deposition layer with a uniform thickness can be formed on the resin layer. This is thought to enable the obtained deposition paper to exhibit excellent barrier properties. The upper limit of the glass transition temperature of the resin is not particularly limited, but is, for example, 200° C. or lower. As described below, when each resin layer contains a polyurethane resin and a polyester resin, the glass transition temperature is preferably 150° C. or lower, more preferably 140° C. or lower, and even more preferably 135° C. or lower. The glass transition temperature of the resin contained in each resin layer is measured by scraping off a part of each resin layer of the base paper for deposition paper, and measuring the glass transition temperature in accordance with JIS K 7121:1987. If the glass transition temperature is 50° C. or higher, it can be said that each resin layer contains a resin having a glass transition temperature of 50° C. or higher. In other words, each resin layer has a glass transition temperature measured in accordance with JIS K 7121:1987 of preferably 50° C. or higher, and the upper limit is not particularly limited, but is, for example, 200° C. or lower. The resins contained in each resin layer may be the same or different, but are preferably the same.

[0047] Each resin layer preferably contains a water-suspendable polymer, more preferably contains mainly a water-suspendable polymer. The water-suspendable polymer preferably has a glass transition temperature of 50° C. or higher, and the glass transition temperature of the water-suspendable polymer is synonymous with the glass transition temperature of the resin described above. Here, "each resin layer mainly contains a water-suspendable polymer" means that the content of the water-suspendable polymer in each resin layer is, for example, 50% by mass or more, preferably 60% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, even more preferably 90% by mass or more, and particularly preferably 95% by mass or more. The upper limit is not particularly limited, but is 100% by mass or less. Each resin layer may further contain any component other than the water-suspendable polymer.

[0048] (Water-suspended polymer) The water-suspendable polymer contained in each resin layer is not particularly limited. Examples of the water-suspendable polymer include alkyd resins; (meth)acrylic (co)polymers, styrene-(meth)acrylic resins; olefin-unsaturated carboxylic acid copolymers such as ethylene-acrylic acid copolymers and ethylene-methacrylic acid copolymers; vinyl alcohol resins such as polyvinyl alcohol resins, ethylene-vinyl alcohol copolymer resins, and ethylene-modified polyvinyl alcohol resins; cellulose resins; polyurethane resins; and polyester resins. The water-suspendable polymer may be used alone or in combination of two or more. The water-suspendable polymer preferably contains one or more selected from the group consisting of vinyl alcohol resins, polyurethane resins, and polyester resins, and from the viewpoint of improving the barrier properties, it is more preferable to contain one or more selected from the group consisting of polyurethane resins and polyester resins, and it is even more preferable to contain a polyurethane resin.

[0049] <Polyurethane resin> The polyurethane-based resin contained in each resin layer is not particularly limited, and is preferably, for example, one or more selected from the group consisting of polyurethane-based resin dispersions and emulsions, more preferably one that can be prepared into a polyurethane-based resin dispersion or emulsion, and even more preferably one that can be prepared into a polyurethane-based resin dispersion.

[0050] The polyurethane resin contained in each resin layer preferably contains at least one selected from the group consisting of a constituent unit derived from meta-xylylene diisocyanate and a constituent unit derived from hydrogenated meta-xylylene diisocyanate. When the polyurethane resin contains at least one of a constituent unit derived from meta-xylylene diisocyanate and a constituent unit derived from hydrogenated meta-xylylene diisocyanate, the total content of the constituent units derived from meta-xylylene diisocyanate and the constituent units derived from hydrogenated meta-xylylene diisocyanate relative to the total amount of the constituent units derived from polyisocyanate is preferably 50 mol% or more. Such a polyurethane resin exhibits high cohesive strength due to hydrogen bonds and the stacking effect between xylylene groups, and therefore has excellent gas barrier properties. The above content is 1 The identification can be performed using known analytical techniques such as H-NMR.

[0051] The polyurethane resin may have a hydroxyl group, and the hydroxyl value is preferably 50 mgKOH / g or more and 1000 mgKOH / g or less, more preferably 100 mgKOH / g or more, even more preferably 150 mgKOH / g or more, and more preferably 800 mgKOH / g or less, even more preferably 600 mgKOH / g or less. If the hydroxyl value of the polyurethane resin is within the above range, it is preferable because it has excellent oxygen barrier properties.

[0052] -Oxygen permeability- The polyurethane resin contained in each of the resin layers preferably has an oxygen permeability of 100 mL / (m) at 23° C. and 50% RH when converted into a sheet having a thickness of 25 μm. 2 ·day·atm) or less, and more preferably 50mL / (m 2 ·day·atm) or less, and more preferably 25mL / (m 2 ·day·atm) or less, and even more preferably 10 mL / (m 2 ·day·atm) or less. In this specification, the oxygen permeability is measured using an oxygen permeability measuring device (OX-TRAN2 / 22, manufactured by MOCON) under conditions of 23°C and 50% RH.

[0053] As the polyurethane resin, a synthetic product may be used, for example, the polyurethane resin described in International Publication No. 2015 / 016069. As the polyurethane resin, a commercially available product may be used, for example, "Takelac W series (trade name)", "Takelac WPB series (trade name)", "Takelac WS series (trade name)" manufactured by Mitsui Chemicals, Inc., and specifically, Takelac WPB-341 and Takelac WPB-341M are exemplified. Other commercially available products include "HPU W-003" (hydroxy polyurethane, hydroxyl value 235 mg KOH / g) manufactured by Dainichiseika Chemicals Co., Ltd.

[0054] <Polyester resin> The polyester-based resin contained in each resin layer is not particularly limited, and is preferably, for example, one or more selected from the group consisting of polyester-based resin dispersions and emulsions, more preferably one that can be prepared into a polyester-based resin dispersion or emulsion, and even more preferably one that can be prepared into a polyester-based resin dispersion.

[0055] As the polyester-based resin, commercially available products may be used, such as the "ELITEL KT Series (product name)" manufactured by Unitika Ltd. and the "LANDY PL Series (product name)" manufactured by Miyoshi Oil & Fats Co., Ltd., and specific examples thereof include ELITEL KT-8803 and LANDY PL-3000.

[0056] (optional ingredient) Optional components that may be contained in the resin layer include resins other than the water-dispersible polymer and additives, such as silane coupling agents, antifoaming agents, surfactants, pigments, antioxidants, antistatic agents, dyes, plasticizers, lubricants, and mold release agents.

[0057] <Pigment coating layer> The base paper for metallized paper of this embodiment may have a pigment coating layer on the side opposite to the side of the paper substrate having two or more resin layers. By providing a pigment coating layer, the base paper for metallized paper of this embodiment can be used to obtain metallized paper with excellent printability. The pigment coating layer is preferably composed mainly of a pigment and a binder. Note that "the pigment coating layer is mainly composed of a pigment and a binder" means that the total content of the pigment and binder in the pigment coating layer is, for example, 50% by mass or more, preferably 60% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, even more preferably 90% by mass or more, and particularly preferably 95% by mass or more. The upper limit is not particularly limited, but is 100% by mass. Note that the pigment coating layer may further contain any component other than the pigment and binder. From the viewpoint of the above effect, it is preferable to perform a calendar treatment on the pigment coating layer.

[0058] (Pigments) The pigment contained in the pigment coating layer is not particularly limited, and examples thereof include inorganic pigments such as kaolin, clay, engineered kaolin, delaminated clay, calcined clay, heavy calcium carbonate, light calcium carbonate, talc, titanium dioxide, barium sulfate, calcium sulfate, zinc oxide, silicic acid, silicate salts, colloidal silica, and satin white; and organic pigments such as solid, hollow, and core-shell types. These may be used alone or in combination of two or more. Among these, at least one selected from the group consisting of kaolin and calcium carbonate is preferred, and it is more preferred to use kaolin and calcium carbonate in combination, and it is even more preferred to use kaolin, heavy calcium carbonate, and light calcium carbonate in combination.

[0059] From the viewpoint of printability, the pigment content in the pigment coating layer is preferably 50% by mass or more and 98% by mass or less, more preferably 60% by mass or more, even more preferably 70% by mass or more, and more preferably 90% by mass or less, even more preferably 85% by mass or less.

[0060] (binder) The binder contained in the pigment coating layer is not particularly limited, and examples thereof include styrene-butadiene resins; acrylic resins such as methyl (meth)acrylate copolymers and styrene-(meth)acrylic copolymers; olefin-unsaturated carboxylic acid copolymers such as ethylene-(meth)acrylic acid copolymers; dextrin, mannan, chitosan, arabinogalactan, glycogen, inulin, pectin, hyaluronic acid, hydroxyethylated starch, oxidized starch, etherified starch, phosphate esterified starch, enzyme-modified starch, and modified starch obtained by flash drying thereof, as well as natural polysaccharides and their oligomers and modified products. The binder may be used alone or in combination of two or more kinds. Among these, it is preferable that the resin is one or more selected from the group consisting of an acrylic resin, a styrene-butadiene resin, and modified starch, it is more preferable that the resin is one or more selected from the group consisting of a styrene-(meth)acrylic copolymer, a styrene-butadiene resin, and oxidized starch, it is even more preferable that the resin is one or more selected from the group consisting of a styrene-butadiene resin and oxidized starch, and it is even more preferable that the two are used in combination.

[0061] The content of the binder in the pigment coating layer is preferably 2% by mass or more and 50% by mass or less, more preferably 5% by mass or more, even more preferably 10% by mass or more, even more preferably 15% by mass or more, and more preferably 45% by mass or less, even more preferably 40% by mass or less, and even more preferably 35% by mass or less. The content of the binder in the pigment coating layer is preferably the above-mentioned lower limit or more from the viewpoint of increasing the strength of the pigment coating layer and suppressing defects and facility stains in the pigment coating layer, and is preferably the above-mentioned upper limit or less from the viewpoint of increasing the ink absorption and fixation properties, suppressing deterioration of operability due to blocking, and from the viewpoint of economy. When oxidized starch is contained as the binder, the content of oxidized starch in the pigment coating layer is preferably 1% by mass or more and 10% by mass or less, more preferably 3% by mass or more, and more preferably 7% by mass or less, from the same viewpoints as above.

[0062] (optional ingredient) Optional components that may be contained in the pigment coating layer include adhesives, dispersants, thickeners, water retention agents, defoamers, water resistance agents, colorants, surfactants, etc. Adhesives include proteins such as casein, soy protein, synthetic protein, etc. Starches such as cationic starch, urea phosphate esterified starch, etherified starch such as hydroxyethyl etherified starch, dextrin, etc. cellulose derivatives such as carboxymethyl cellulose, hydroxyethyl cellulose, hydroxymethyl cellulose, etc.

[0063] The coating amount of the pigment coating layer is not particularly limited, but is preferably 3 g / m2 in terms of solid content. 2 More than 30g / m 2 More preferably, it is 5 g / m or less. 2 More preferably, 7 g / m 2 More preferably, it is 20 g / m or more. 2 Less than 15 g / m, more preferably 2 The coating amount of the pigment coating layer is preferably equal to or more than the above lower limit from the viewpoint of printability, and is preferably equal to or less than the above upper limit from the viewpoints of economy and ease of production.

[0064] The method for forming the pigment coating layer is not particularly limited, but a method of forming the pigment coating layer by coating a dispersion containing a pigment and a binder on a paper substrate and drying the same is preferred. The dispersion containing a pigment and a binder is preferably one that uses an aqueous medium containing water as a main component as a solvent.

[0065] <Physical properties of base paper for metallized paper> (Glossiness) In order to enhance the barrier properties (particularly the water vapor barrier properties) of the base paper for metallized paper of this embodiment, the surface having two or more resin layers (the surface on which the metallized layer described below is provided) has a 75° specular gloss measured in accordance with JIS P 8142:2005 of preferably 70.0% or more and 100.0% or less, more preferably 75.0% or more, and even more preferably 80.0% or more. The upper limit of the gloss of the base paper for metallized paper may be 95.0% or less or 90.0% or less. The higher the gloss of the resin layer surface, the more the unevenness of the resin layer surface is suppressed, and the more a metallized layer with a uniform thickness can be formed on the resin layer. The gloss of the base paper for metallized paper can be controlled by the type of resin contained in the resin layer, the thickness of the resin layer, the type of coating solvent, and the like.

[0066] (Thickness) The thickness of the base paper for metallized paper of this embodiment is preferably 10 μm or more and 100 μm or less, more preferably 30 μm or more, and more preferably 80 μm or less. The thickness of the base paper for metallized paper of this embodiment is preferably the above-mentioned lower limit or more from the viewpoint of strength when used as a packaging bag, and is preferably the above-mentioned upper limit or less from the viewpoints of bag making suitability, economic efficiency, and ease of production.

[0067] There is no limitation on the method for producing the base paper for metallized paper of this embodiment, but for example, as a method for producing a base paper for metallized paper having a clay coat layer and two or more resin layers in this order on at least one side of a paper substrate, it is preferable to coat and dry a clay coat layer coating liquid containing an inorganic pigment and a binder on at least one side of the paper substrate to form a clay coat layer (step 1), and then coat and dry a resin layer coating liquid containing a water-dispersible polymer on the clay coat layer to form two or more resin layers (step 2). The resin layer coating liquid may be coated and dried sequentially, or the resin layer coating liquid may be simultaneously coated and dried, and sequential coating and drying are preferred. That is, it is preferable to coat and dry the resin layer coating liquid containing a water-dispersible polymer on the clay coat layer two or more times, and from the viewpoint of increasing the gloss of the resin layer surface, it is preferable to form the second and subsequent resin layers in step 2 by performing a calendar treatment after forming the first resin layer. From the same viewpoint, it is preferable to subject the two or more resin layers obtained in step 2 to a calendar treatment. When a clay coating layer and two or more resin layers are formed on one side of the paper base material by steps 1 and 2, a step A may be included in which a coating liquid for a pigment coating layer is applied to the other side of the paper base material and dried to form a pigment coating layer. Step A may be performed before step 1, between steps 1 and 2, or after step 2. From the viewpoints of printability and bag-making suitability, it is preferable to perform a calendar treatment on the pigment coating layer obtained in step A.

[0068] In preparing the resin layer coating liquid, water, an organic solvent, or a mixed solvent of water and an organic solvent may be used as the medium (solvent or dispersion medium), but it is more preferable to use water or a mixed solvent of water and an organic solvent. Examples of organic solvents include ethyl acetate, ethanol, and isopropanol. Examples of mixed solvents of water and an organic solvent include a water / ethanol mixed solvent and a water / isopropanol mixed solvent. From the viewpoint of improving the barrier property, it is preferable to use a resin layer coating liquid in step 2 in which a water-suspendable polymer is dispersed in water, a water / ethanol mixed solvent, or a water / isopropanol mixed solvent. When water is used as the medium, the solid content in the coating liquid for the resin layer is, from the viewpoint of facilitating the formation of the resin layer, for example, 1 mass % or more and 30 mass % or less, preferably 2 mass % or more and 25 mass % or less, more preferably 3 mass % or more and 20 mass % or less, and even more preferably 5 mass % or more and 15 mass % or less. When a mixed solvent of water and an organic solvent is used as the medium, the solid content in the resin layer coating fluid is, for example, from 1% by mass to 30% by mass, from the viewpoint of facilitating the formation of the resin layer.

[0069] In the case of a two-layer resin layer, from the viewpoint of improving the barrier property, it is preferable to use water or a water / isopropanol mixed solvent as a medium in the preparation of the coating liquid for the first resin layer, and to use ethyl acetate, a water / ethanol mixed solvent, or a water / isopropanol mixed solvent as a medium in the preparation of the coating liquid for the second resin layer. It is more preferable to use water or a water / isopropanol mixed solvent as a medium in the preparation of the coating liquid for the first resin layer, and to use a water / ethanol mixed solvent or a water / isopropanol mixed solvent as a medium in the preparation of the coating liquid for the second resin layer. The content (mass%) of the organic solvent in the water / organic solvent (ethanol or isopropanol) mixed solvent used for the second layer is preferably equal to or greater than the content (mass%) of isopropanol in the water / isopropanol mixed solvent used for the first layer, and it is more preferable that the content (mass%) of the organic solvent in the water / organic solvent (ethanol or isopropanol) mixed solvent used for the second layer is greater than the content (mass%) of isopropanol in the water / isopropanol mixed solvent used for the first layer. From the viewpoints of practicality and economy, it is preferable that the coating liquids for the first and second layers have the same composition. When the resin layer has three or more layers, from the viewpoint of improving the barrier property, it is preferable to use water or a water / isopropanol mixed solvent as a medium in preparing the coating liquid for the first resin layer, to use a water / ethanol mixed solvent or a water / isopropanol mixed solvent as a medium in preparing the coating liquid for the second resin layer, and to use a water / ethanol mixed solvent or a water / isopropanol mixed solvent in preparing the coating liquid for the third or more resin layers.

[0070] The mass ratio of water to the organic solvent (water / organic solvent) in the mixed solvent of water and an organic solvent is, for example, 50 / 50 to 99 / 1, preferably 55 / 45 to 95 / 5, and more preferably 60 / 40 to 90 / 10.

[0071] When the resin layer and the pigment coating layer are subjected to a calendar treatment, the line pressure is, from the viewpoint of smoothing the surface while maintaining the barrier properties of the resin layer, preferably from 5 kg / cm to 200 kg / cm, more preferably from 10 kg / cm to 15 kg / cm, and more preferably from 100 kg / cm to 50 kg / cm, even more preferably from 30 kg / cm to 50 kg / cm. Furthermore, when adjusting the temperature in the calendaring process, the temperature is not particularly limited, but from the viewpoint of preventing deterioration of the paper base material and the pigment coating layer due to heat while enhancing the effect of the process, and from the viewpoint of preventing the resin layer and the pigment coating layer from sticking to the roll, the temperature is preferably from 20°C to 80°C, more preferably from 30°C to 35°C, even more preferably from 35°C to 70°C, even more preferably from 60°C to 70°C. The calendaring may be performed in either one stage or multiple stages. From the viewpoint of further improving the gloss of the resin layer surface and further improving the printability and / or automatic packaging suitability of the vapor-deposited paper, it is preferable to perform the calendaring in multiple stages (two or more stages), more preferably five or more stages, and even more preferably ten or more stages. Although there is no particular upper limit, it is preferably 15 stages or less.

[0072] [Metal-deposited paper] The present invention also provides a metal-deposited paper having a metal-deposited layer on two or more resin layers of the base paper for the metal-deposited paper. From the viewpoint of improving printability and packaging suitability, the metal-deposited paper of this embodiment may have a pigment coating layer on the side of the paper substrate opposite to the side having the metal-deposited layer. That is, the metal-deposited paper of this embodiment may have a pigment coating layer, a paper substrate, a clay coat layer, two or more resin layers, and a metal-deposited layer in this order. The preferred embodiment of the pigment coating layer is as described above. <Vapour-deposited layer> The vapor-deposited layer has at least one of a layer made of metal and a layer made of ceramic. That is, the vapor-deposited layer may be any of a layer made of metal, a layer made of ceramic, and a laminate of a metal layer and a ceramic layer. When the vapor-deposited layer is a laminate of a metal layer and a ceramic layer, the metal layer may be on the resin layer side of the base paper for vapor-deposited paper, and the ceramic layer may be on the resin layer side of the base paper for vapor-deposited paper, and there is no particular limitation.

[0073] The vapor-deposited layer may be a layer made of a metal, a layer made of ceramic, or a laminate of these, but a layer made of a metal is preferred. When the vapor-deposited layer is a layer made of a metal, specific examples of the metal include aluminum and titanium. These may be used alone or in combination of two or more. Among these, aluminum is preferred. When the vapor-deposited layer is a layer made of ceramic, specific examples of the ceramic include silicon oxide, titanium oxide, aluminum oxide, etc. These may be used alone or in combination of two or more. Among these, silicon oxide and aluminum oxide are preferred.

[0074] The vapor deposition layer is preferably a layer made of one or more materials selected from the group consisting of aluminum, aluminum oxide, silicon oxide, and diamond-like carbon, and from the viewpoint of ease of production, is more preferably a layer made of one or more materials selected from the group consisting of aluminum, aluminum oxide, and diamond-like carbon, and is even more preferably a layer made of one or more materials selected from the group consisting of aluminum and aluminum oxide.

[0075] (Thickness) The thickness of the deposition layer is preferably 1 nm or more and 1000 nm or less, more preferably 2 nm or more, even more preferably 3 nm or more, and more preferably 500 nm or less, and even more preferably 100 nm or less. From the viewpoint of barrier properties and cost, the thickness of the deposition layer is preferably 10 nm or more and 80 nm or less, more preferably 25 nm or more, and more preferably 70 nm or less. From the viewpoint of adhesion to other layers and cost, the thickness of the deposition layer is preferably 4 nm or more and 100 nm or less, more preferably 5 nm or more, more preferably 70 nm or less, and even more preferably 60 nm or less.

[0076] <Overcoat layer> The metallized paper of this embodiment may have an overcoat layer between the metallized layer and the heat seal layer. The overcoat layer is a layer for protecting the metallized layer. The metallized paper of this embodiment has a certain level of barrier property due to the metallized layer, but the barrier property can be further improved by having an overcoat layer on the metallized layer. In addition, the metallized layer is less likely to be damaged by processing such as bending, and even if it is damaged, the barrier property can be guaranteed by the overcoat layer, so that excellent barrier property can be maintained.

[0077] The overcoat layer is not particularly limited and may contain an organic compound, an inorganic compound, or both. That is, the overcoat layer may be any of an organic layer, an inorganic layer, and an organic-inorganic hybrid layer. Examples of the organic compound include vinyl alcohol resins such as ethylene-vinyl alcohol copolymer resin, polyvinyl alcohol, and ethylene-modified polyvinyl alcohol, polyurethane resins, (meth)acryloyl compounds, and reaction products of (meth)acryloyl compounds. Examples of the inorganic compound include oxides of silicon, aluminum, and the like.

[0078] Among these, the overcoat layer is preferably one of the resins exemplified as being contained in the resin layer of the base paper for metallized paper, more preferably contains at least one selected from the group consisting of polyurethane-based resins, polyester-based resins, and vinyl alcohol-based resins, even more preferably contains at least one selected from the group consisting of polyurethane-based resins and vinyl alcohol-based resins, even more preferably is capable of being prepared into one or more selected from the group consisting of a water / alcohol solution of a vinyl alcohol-based resin (a solution containing a vinyl alcohol-based resin, water, and alcohol), a polyurethane-based resin dispersion, and an emulsion, even more preferably is capable of being prepared into a polyurethane-based resin dispersion or emulsion, and even more preferably is capable of being prepared into a polyurethane-based resin dispersion.

[0079] The polyurethane resin, polyester resin, and vinyl alcohol resin that the overcoat layer may contain may be the same type as the resin contained in the resin layer of the base paper for metallized paper described above, or may be a different type. In addition, the synthetic products and commercially available products listed as usable for the resin layer of the base paper for metallized paper may be used.

[0080] The content of the polyurethane-based resin, polyester-based resin, and vinyl alcohol-based resin in the overcoat layer is preferably 80% by mass or more, more preferably 90% by mass or more, even more preferably 95% by mass or more, and even more preferably 99% by mass or more, and the upper limit is not particularly limited, but is 100% by mass.

[0081] The overcoat layer may contain other resins and additives within the range that does not impair the effects of the present invention. Examples of additives include surfactants, pigments, antioxidants, antistatic agents, dyes, plasticizers, lubricants, and release agents. When the polyurethane resin is used as an aqueous dispersion, it is preferable to use a dispersant to disperse the polyurethane resin in an aqueous medium and obtain a uniform overcoat layer film.

[0082] The coating amount of the overcoat layer is preferably 0.1 g / m2 in terms of solid content. 2 More than 10g / m 2 More preferably, it is 0.2 g / m or less. 2 More preferably, 0.3 g / m 2 More preferably, it is 7 g / m or more. 2 Less than 4 g / m, more preferably 2 The coating amount of the overcoat layer is preferably equal to or more than the above-mentioned lower limit from the viewpoint of protecting the vapor-deposited layer, and is preferably equal to or less than the above-mentioned upper limit from the viewpoint of recyclability of the vapor-deposited paper.

[0083] The thickness of the overcoat layer is preferably 0.1 μm or more and 10 μm or less, more preferably 0.2 μm or more, even more preferably 0.3 μm or more, and more preferably 7 μm or less, even more preferably 4 μm or less. From the viewpoint of protecting the deposition layer, the thickness of the overcoat layer is preferably the lower limit value or more, and from the viewpoint of recyclability of the deposition paper, the thickness of the overcoat layer is preferably the upper limit value or less.

[0084] The method for forming the overcoat layer is not particularly limited, but it is preferable to form the overcoat layer by coating an aqueous medium containing an organic compound or an inorganic compound that constitutes the overcoat layer and drying it.

[0085] In the metallized paper of this embodiment, the overcoat layer may be the outermost layer. Even if the overcoat layer is the outermost layer, it does not impair the design of the glossy metallized layer. In addition, when the metallized layer is present on both sides, the overcoat layer may be present on one or both sides. Among these, it is preferable to have an overcoat layer on one side. By having an overcoat layer on one side, production efficiency is excellent.

[0086] <Heat seal layer> The metallized paper of the present embodiment preferably has a heat seal layer on the metallized layer, and more preferably has a heat seal layer on the overcoat layer. The heat seal layer is a layer that is melted and bonded by heating, ultrasonic waves, etc. The method for forming the heat seal layer and the resin used for the heat seal layer are as described below.

[0087] The thickness of the heat seal layer is not particularly limited, but is preferably 1 μm or more and 25 μm or less, and may be 10 μm or less, or 5 μm or less. If it is 1 μm or more, sufficient heat sealability can be ensured. Also, if it is 25 μm or less, it is possible to impart maceration properties and obtain a metal-deposited paper with excellent recyclability.

[0088] The basis weight of the heat seal layer (the amount of coating when the heat seal layer is formed by coating) is preferably 0.5 g / m2 in terms of solid content. 2 More than 25g / m 2 More preferably, it is 1.0 g / m or less. 2 More preferably, 2.5 g / m 2 More preferably, it is 10 g / m or more. 2 Less than 5.0 g / m, more preferably 5.0 g / m 2 The basis weight of the heat seal layer is preferably equal to or more than the above lower limit from the viewpoint of ensuring sufficient heat sealability, and is preferably equal to or less than the above upper limit from the viewpoint of providing a metal-deposited paper that is capable of being provided with releasability and has excellent recyclability.

[0089] [Method of manufacturing metallized paper] The method for producing the metal-deposited paper of this embodiment is not limited, but preferably includes the steps of forming a metal-deposited layer by depositing at least one of metal and ceramic on the resin layer of the base paper for metal-deposited paper, which has a clay coat layer and two or more resin layers in this order on at least one side of the paper substrate, and applying a coating liquid for a heat-sealing layer onto the deposition layer and drying to form a heat-sealing layer. In this case, an overcoat layer may be formed by coating on the deposition layer before forming the heat-sealing layer.

[0090] The method for depositing metal or ceramic is preferably a method in which the metal or ceramic is directly deposited in vacuum on the surface of two or more resin layers of the base paper for metallized paper.

[0091] It is preferable to form the overcoat layer directly on the deposition layer from the viewpoint of efficiently protecting the deposition layer and enhancing the barrier property. The overcoat layer is preferably formed by applying a coating liquid for the overcoat layer and drying it. By using the method of applying a coating liquid for the overcoat layer to form the overcoat layer, it is possible to form an overcoat layer having a relatively thin film of 10 μm or less. By forming such a relatively thin overcoat layer, it is possible to impart excellent disintegration properties and obtain a deposition paper having excellent recyclability.

[0092] The overcoat layer coating liquid used here may be an aqueous medium of an organic compound or an inorganic compound constituting the overcoat layer. Among these, a water / alcohol solution of a vinyl alcohol resin, a solution using an organic solvent to dissolve a polyurethane resin, a dispersion using an organic solvent to disperse a polyurethane resin, and a dispersion using an aqueous medium to disperse a polyurethane resin are preferred, and from the viewpoints of coatability and environmental load, a water / alcohol solution of a vinyl alcohol resin and a dispersion using an aqueous medium to disperse a polyurethane resin are more preferred.

[0093] Examples of methods for applying the coating solution for the overcoat layer include bar coating, blade coating, squeeze coating, air knife coating, roll coating, gravure coating, and transfer coating, and a coating machine such as a fountain coater or a slit die coater may be used.

[0094] The coating liquid for the overcoat layer is applied and then dried to remove the organic solvent or aqueous medium, thereby obtaining a metal-deposited paper having an overcoat layer on the metal-deposited layer.

[0095] A heat seal layer containing a thermoplastic resin may be formed on the deposition layer or the overcoat layer. Methods for forming the heat seal layer include a method of applying a thermoplastic resin solution or a thermoplastic resin dispersion and drying it, a method of extrusion laminating a thermoplastic resin, and a method of dry laminating a thermoplastic resin film. Among these, it is preferable to apply a thermoplastic resin solution or a thermoplastic resin dispersion and dry it to obtain a heat seal layer, or to dry laminate a thermoplastic resin film to obtain a heat seal layer. The thermoplastic resin used to form the heat seal layer may be one type alone or two or more types.

[0096] The thermoplastic resin solution or thermoplastic resin dispersion used here may be a solution using an organic solvent that dissolves the thermoplastic resin, a dispersion using an organic solvent that disperses the thermoplastic resin, or a dispersion using an aqueous medium, and from the standpoint of coatability and environmental load, a dispersion using an aqueous medium is preferred. Thermoplastic resins suitable for dispersions using aqueous media may be either natural resins or synthetic resins, and examples thereof include starch derivatives, casein, shellac, polyvinyl alcohol and its derivatives, acrylic resins, ionomer resins, maleic acid resins, urethane resins, polyester resins, styrene-butadiene resins, vinyl chloride resins, and polyolefin resins. More specifically, examples of the acrylic resin include an acrylic resin copolymerized with (meth)acrylic acid and its alkyl ester or styrene as a monomer component, a styrene-maleic acid resin, a styrene-acrylic acid-maleic acid resin, a water-soluble polyurethane resin, and a water-soluble polyester resin. As the ionomer resin, for example, an ethylene-acrylic acid copolymer ionomer or an ethylene-methacrylic acid copolymer ionomer is preferable. Here, an ionomer is a polymer neutralized with a cation, and the cation may be a metal ion or an ammonium ion (NH4 + ), and organic ammonium ions. Metal ions include lithium ions (Li + ), sodium ion (Na+ ), potassium ion (K + ), magnesium ions (Mg 2+ ), calcium ion (Ca 2+ ), alkaline earth metal ions such as zinc ions (Zn 2+ ), copper ions (Cu 2+ Among these, sodium ions are preferred as the metal ions from the viewpoint of availability and the like. Among these, from the viewpoints of the stability of the coating liquid and the solvent resistance of the coating layer, at least one selected from starch derivatives, casein, shellac, polyvinyl alcohol and its derivatives, ionomer-based resins, acrylic resins, and maleic acid-based resins is preferred, at least one selected from starch derivatives, polyvinyl alcohol, polyvinyl alcohol derivatives, ionomer-based resins, acrylic resins, and maleic acid-based resins is more preferred, at least one selected from starch derivatives, polyvinyl alcohol, polyvinyl alcohol derivatives, ionomer-based resins, and acrylic resins is even more preferred, at least one selected from polyvinyl alcohol, polyvinyl alcohol derivatives, and ionomer-based resins is even more preferred, and ionomer-based resins are particularly preferred.

[0097] Methods for applying the thermoplastic resin solution or thermoplastic resin dispersion include a bar coating method, a blade coating method, a squeeze coating method, an air knife coating method, a roll coating method, a gravure coating method, and a transfer coating method, and a coating machine such as a fountain coater or a slit die coater may be used.

[0098] The metallized paper coated with the thermoplastic resin solution or thermoplastic resin dispersion can be dried to remove the organic solvent or aqueous medium, to obtain a metallized paper having a heat seal layer on the overcoat layer.

[0099] Next, examples of the thermoplastic resin constituting the thermoplastic resin film in the dry laminate include polyolefin resins, polyamide resins, polyester resins, and polyvinylidene chloride resins.

[0100] From the viewpoint of heat sealability and barrier property, the polyolefin resin is more preferably at least one selected from the group consisting of polyethylene, polypropylene and an ethylene-propylene copolymer, and even more preferably at least one of polyethylene and polypropylene. The polyolefin resin film used for dry lamination may be unstretched, uniaxially stretched or biaxially stretched, but from the viewpoint of heat sealability, it is preferably unstretched. The polyethylene may be low density polyethylene (LDPE), linear low density polyethylene (LLDPE), medium density polyethylene (MDPE), or high density polyethylene (HDPE).

[0101] Examples of polyamide resins include nylon 6, nylon 11, nylon 12, nylon 66, nylon 610, and nylon 612.

[0102] Examples of polyester resins include polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polybutylene terephthalate (PBT), and derivatives thereof.

[0103] Polyvinylidene chloride resin (PVDC) is a synthetic resin obtained by polymerizing vinylidene groups containing chlorine, and may be a copolymer with vinyl chloride, acrylonitrile, or the like.

[0104] The adhesive used in dry lamination is not particularly limited, and may be any of solvent-free, organic solvent-based, and water-based types, but from the viewpoint of ensuring the shape stability of the paper substrate, it is preferable to use an organic solvent-based or solvent-free adhesive. Examples of the main component constituting the adhesive include (meth)acrylic acid ester copolymers, α-olefin copolymers, ethylene-vinyl acetate copolymers, polyvinyl alcohol, polyurethane, styrene-butadiene copolymers, polyvinyl chloride, epoxy resins, melamine resins, silicone resins, natural rubber, casein, starch, etc. Among these, from the viewpoints of easy availability and obtaining good adhesive properties, (meth)acrylic acid ester copolymers, ethylene-vinyl acetate copolymers, and polyurethanes are preferred, and polyurethanes are more preferred. As the adhesive, a commercially available adhesive may be used as appropriate, for example, a combination of Nipporan ID-816 (manufactured by Tosoh Corporation) and HARDENER 300 (manufactured by Tosoh Corporation), or a combination of Dickdry LX-500 (manufactured by DIC Corporation) and Dickdry KW-75 (manufactured by DIC Corporation).

[0105] The method for applying the adhesive may be appropriately selected from conventionally known methods, and is not particularly limited. Examples of the method include a roll coater, a die coater, a gravure coater, and a spray coater.

[0106] <Physical properties of metallized paper> (Thickness) The thickness of the metallized paper in this embodiment is preferably 20 μm or more and 200 μm or less, more preferably 50 μm or more, and more preferably 150 μm or less. The thickness of the metallized paper is measured in accordance with JIS P 8118:2014.

[0107] (Glossiness) In the metallized paper of this embodiment, the 20° specular gloss of the heat seal layer surface measured in accordance with JIS P 8142:2005 is preferably 40.0% or more and 100.0% or less, more preferably 44.0% or more. When the gloss of the resin layer surface of the base paper for metallized paper is high, the metallized paper having a metallized layer on the resin layer has a gloss of the above-mentioned lower limit or more and has excellent barrier properties (particularly water vapor barrier properties). The upper limit of the gloss of the metallized paper may be 95.0% or less, and when the heat seal layer is provided by coating, it may be 70.0% or less, 60.0% or less, or 50.0% or less. The gloss of the metallized paper can be controlled by the type of resin contained in the resin layer, the thickness of the resin layer, the type of resin contained in the heat seal layer, the type of coating solvent, etc.

[0108] (Heat seal peel strength) The metallized paper of this embodiment preferably has a maximum load heat seal peel strength of 2 N / 15 mm or more when the heat seal layers are heat sealed together under conditions of 140°C, 0.2 MPa, and 1 second, and a test piece having a width of 15 mm is T-peeled at a tensile speed of 300 mm / min. If the heat seal peel strength is within the above range, the paper is excellent in suitability as a barrier packaging. The upper limit of the heat seal peel strength is not particularly limited, but is, for example, 20 N / 15 mm or less.

[0109] (Oxygen permeability) The oxygen permeability of the metallized paper of this embodiment at 23° C. and 50% RH is preferably 1.00 mL / (m 2 ·day·atm) or less, preferably 0.60mL / (m 2 ·day·atm) or less, and more preferably 0.30mL / (m 2 ·day·atm) or less, and even more preferably 0.23 mL / (m 2 ·day·atm) or less (lower limit: 0mL / (m 2 The oxygen permeability of the metallized paper is measured by the method described in the examples.

[0110] (Water vapor permeability) The water vapor transmission rate of the metallized paper of this embodiment at 40° C. and 90% RH is preferably 1.00 g / (m2 ·day) or less, more preferably 0.80g / (m 2 ·day) or less, and more preferably 0.60 g / (m 2 ·day), and even more preferably 0.40 g / (m 2 ·day) or less, and particularly preferably 0.30 g / (m 2 ·day) or less (Lower limit: 0g / (m 2 The water vapor permeability of the metallized paper is measured by the method described in the examples.

[0111] Taking advantage of the excellent barrier properties described above, the metallized paper of this embodiment can be suitably used as a packaging material (particularly, packaging bags) for foods such as coffee, confectionery, and milk, medicines, medical products, electronic components, etc., and also has excellent recyclability. Therefore, packaging bags made of the metallized paper of this embodiment can be used for various purposes.

[0112] A packaging bag according to another embodiment of the present disclosure is a packaging bag made using the above-mentioned vapor-deposited paper. Examples of the packaging bag include a standing pouch type, a side seal type, a two-sided seal type, a three-sided seal type, a four-sided seal type, an envelope seal type, a joint seal type (pillow seal type), a pleated seal type, a flat bottom seal type, a square bottom seal type, and a gusset type. The packaging bag of the present embodiment may be formed by folding one of the above-mentioned vapor-deposited papers having a heat seal layer or by overlapping two sheets of the paper together so that the heat seal layers face each other and heat-sealing the peripheral edges of the paper to form the above-mentioned shape, or by folding the above-mentioned vapor-deposited paper or by overlapping two sheets of the paper together and bonding the peripheral edges of the paper together with an adhesive to form the above-mentioned shape.

[0113] The vapor-deposited paper of the present embodiment may be used for purposes other than packaging bags, for example, soft packaging materials such as lids and labels, liquid containers such as milk cartons (hereinafter also referred to as liquid paper containers), packaging containers such as cups, trays, plates, lids, laminated tubes, etc. In this case, the contents to be packaged may be liquids, solids (granular materials, powdery materials, etc.), or gels. EXAMPLES

[0114] The features of the present invention will be explained in more detail below with reference to examples and comparative examples. The materials, amounts used, ratios, processing contents, processing procedures, etc. shown in the following examples can be appropriately changed without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be interpreted as being limited by the specific examples shown below. Furthermore, the operations of the examples and comparative examples were carried out under the conditions of room temperature (20-25°C) and normal humidity (40-50% RH (relative humidity 40-50%)) unless otherwise specified.

[0115] <Example 1> A coating solution for the clay coat layer was prepared by mixing 60 parts by mass (solid content) of kaolin (Imerys, Contour Xtreme, aspect ratio 33, average particle size d50: 0.26 μm) and 40 parts by mass (solid content) of a styrene-acrylic copolymer binder ("styrene-acrylic resin" listed in Tables 1 to 3, BASF, Acronal S504). 2 The above clay-coat layer coating solution was applied onto the highly smooth (glossy) surface of a 100-m2 PET bottle (thickness: 62 μm, Oken-type smoothness of glossy surface: 470 seconds, manufactured by Oji F-Tex Co., Ltd.) with a Mayer bar, and dried at 120° C. for 1 minute to form a clay-coat layer (coating amount: 12.0 g / m2). 2 A 7 μm thick film was formed. Next, a 25 μm thick film with an oxygen permeability (23° C., 50% RH) of 2.0 mL / (m 2 A coating solution for the first resin layer (solid concentration 10% by mass) was prepared by diluting an aqueous dispersion of a polyurethane resin binder (solid concentration 30% by mass, Mitsui Chemicals, Takelac WPB-341: glass transition temperature 110°C) having a molecular weight of 1.0001 / day atm with water, and the coating solution was applied with a Mayer bar and dried at 120°C for 1 minute to form a first resin layer (coating amount 1.0 g / m 2 A 1.0 μm thick film was formed. Next, the first resin layer surface was contacted with a chilled roll and the opposite surface (the less smooth surface of the paper base material) with a cotton roll at a linear pressure of 20 kg / cm, and the rolls were heated to 40°C to perform a 12-stage supercalendering process. Furthermore, the oxygen permeability (23°C, 50% RH) of a 25 μm thick film is 2.0 mL / (m 2 To 40 parts by mass of an aqueous dispersion of a polyurethane resin binder (solid concentration 25% by mass, Mitsui Chemicals, Takelac WPB-341M: glass transition temperature 110°C), 30 parts by mass of water and 30 parts by mass of isopropyl alcohol (Fujifilm Wako Pure Chemical Industries, Ltd.) were added to adjust the solid concentration to 10% by mass to obtain a coating liquid for the second resin layer (isopropyl alcohol content in the coating liquid: 30% by mass). The coating liquid was applied onto the first resin layer with a Mayer bar and dried at 120°C for 1 minute to form a second resin layer (coating amount 1.0 g / m 2 A metallized paper base sheet (thickness: 1.0 μm) was formed.

[0116] <Example 2> A base paper for vapor-deposited paper was obtained in the same manner as in Example 1, except that instead of the coating liquid for the second resin layer prepared in Example 1, a coating liquid for the second resin layer (isopropyl alcohol content in the coating liquid: 15% by mass) was used, which was obtained by adding 45 parts by mass of water and 15 parts by mass of isopropyl alcohol to 40 parts by mass of an aqueous dispersion of a polyurethane resin binder (solid concentration: 25% by mass, Takelac WPB-341M manufactured by Mitsui Chemicals, Inc.: glass transition temperature: 110°C) to adjust the solid concentration to 10% by mass.

[0117] <Example 3> A base paper for vapor-deposited paper was obtained in the same manner as in Example 1, except that instead of the coating liquid for the second resin layer prepared in Example 1, a coating liquid for the second resin layer (isopropyl alcohol content in the coating liquid: 0 mass%) was used, which was obtained by adding 60 mass parts of water to 40 mass parts of an aqueous dispersion of a polyurethane resin binder (solid concentration: 25 mass%, Mitsui Chemicals, Inc., Takelac WPB-341M: glass transition temperature: 110°C) to adjust the solid concentration to 10 mass%.

[0118] <Example 4> A base paper for metallized paper was obtained in the same manner as in Example 2, except that the thickness of the second resin layer was 0.5 μm.

[0119] <Example 5> A base paper for metallized paper was obtained in the same manner as in Example 2, except that the thickness of the second resin layer was 2.0 μm.

[0120] <Example 6> A base paper for metallized paper was obtained in the same manner as in Example 2, except that the thickness of the second resin layer was 3.0 μm.

[0121] <Example 7> The same procedures as in Example 2 were carried out up to forming the second resin layer. A third resin layer (thickness: 1.0 μm) was further provided on the second resin layer in the same manner as for the second resin layer, to obtain a base paper for metallized paper.

[0122] <Example 8> A base paper for metallized paper was obtained in the same manner as in Example 2, except that in the preparation of the coating liquid for the second resin layer in Example 2, the polyurethane resin was changed to a polyester resin, and the coating liquid for the second resin layer was changed to a solid content of 25% by mass, and the content of isopropyl alcohol in the coating liquid was 15% by mass. Note that as the polyester resin, an aqueous dispersion of polyester resin (Unitika, Elitel KT-8803: glass transition temperature 65°C, solid content of 30% by mass) was used, and a predetermined amount of water and isopropyl alcohol was added to dilute it to the above solid content concentration.

[0123] <Example 9> A base paper for metallized paper was obtained in the same manner as in Example 2, except that the coating method for the first resin layer coating liquid and the second resin layer coating liquid was gravure coating.

[0124] <Example 10> A base paper for metallized paper was obtained in the same manner as in Example 2, except that the thicknesses of the first resin layer and the second resin layer were both 0.2 μm.

[0125] <Example 11> A base paper for metallized paper was obtained in the same manner as in Example 2, except that the thickness of the first resin layer was 0.5 μm.

[0126] <Example 12> A base paper for metallized paper was obtained in the same manner as in Example 2, except that the thickness of the first resin layer was 3.0 μm.

[0127] <Example 13> A base paper for vapor-deposited paper was obtained in the same manner as in Example 2, except that instead of the coating liquid for the first resin layer prepared in Example 2, a coating liquid for the first resin layer (isopropyl alcohol content in the coating liquid: 15% by mass) was used, which was obtained by adding 51.7 parts by mass of water and 15 parts by mass of isopropyl alcohol to 33.33 parts by mass of an aqueous dispersion of a polyurethane resin binder (solid concentration: 30% by mass, Takelac WPB-341 manufactured by Mitsui Chemicals, Inc.: glass transition temperature: 110°C) to adjust the solid concentration to 10% by mass.

[0128] <Example 14> A base paper for vapor-deposited paper was obtained in the same manner as in Example 2, except that ethanol was added instead of isopropyl alcohol to prepare a coating liquid for the second resin layer (solid concentration: 10% by mass, ethanol content in the coating liquid: 15% by mass).

[0129] <Example 15> To an aqueous solution containing 100 parts by mass of kaolin (Imerys, Contour Xtreme, aspect ratio 33, average particle size d50: 0.26 μm) and 0.1 parts by mass of sodium polyacrylate (Toagosei, Aron T-50) as a dispersant, 30 parts by mass of fine kaolin (BASF, Milagros J), 40 parts by mass of light calcium carbonate (Okutama Kogyo Co., Ltd., TP-123CS), and 30 parts by mass of heavy calcium carbonate (Bihoku Powder Industry Co., Ltd., Hydrocarb 90) were added and dispersed using a Coles disperser to prepare a pigment slurry. The pigment (solid content) content of this pigment slurry was set to 70 parts by mass, and 5 parts by mass (solid content) of oxidized starch (Oji Ace A) and 25 parts by mass (solid content) of styrene-butadiene copolymer latex (OJ1000H, manufactured by JSR Corporation) were added as binders to the pigment slurry to prepare a paint for a pigment coating layer with a final solid content concentration of 60% by mass. The second resin layer was formed in the same manner as in Example 2. A paint for a pigment coating layer was applied to the surface of the paper base opposite to the surface on which the first and second resin layers were formed in an amount of 10 g / m2 in terms of solid content. 2 After coating with a Mayer bar so that the coating was as follows, the mixture was dried for 1 minute with a 120°C air dryer to form a pigment coating layer. Next, the second resin layer surface was brought into contact with a chilled roll and the pigment coating layer surface was brought into contact with a cotton roll at a linear pressure of 20 kg / cm, and the rolls were heated to 40°C to perform a 12-stage supercalendering process, thereby obtaining a base paper for metallized paper.

[0130] <Example 16> A base paper for metallized paper was obtained in the same manner as in Example 1, except that instead of the coating liquid for the second resin layer prepared in Example 1, a coating liquid for the second resin layer (ethyl acetate content in the coating liquid: 90% by mass) was used, which was obtained by adding ethyl acetate to an ethyl acetate dispersion of polylactic acid resin (glass transition temperature: 55-60°C, solid concentration: 15% by mass) to adjust the solid concentration to 10% by mass.

[0131] <Example 17> In the same manner as in Example 2, a base paper for metallized paper was obtained.

[0132] <Example 18> In the same manner as in Example 2, a base paper for metallized paper was obtained.

[0133] <Comparative Example 1> A clay coating layer was formed on a paper substrate in the same manner as in Example 1. A resin layer coating liquid obtained in the same manner as in the second resin layer coating liquid of Example 2 was applied onto the clay coating layer with a Mayer bar and dried at 120° C. for 1 minute to form a resin layer (coating amount 1.0 g / m 2 A metallized paper base sheet (thickness: 1.0 μm) was formed.

[0134] <Comparative Example 2> A base paper for metallized paper was obtained in the same manner as in Comparative Example 1, except that the thickness of the resin layer was 2.0 μm.

[0135] <Comparative Example 3> A base paper for metallized paper was obtained in the same manner as in Example 13, except that the thickness of the second resin layer was 5.0 μm.

[0136] <Comparative Example 4> A base paper for metallized paper was obtained in the same manner as in Example 13, except that the thickness of the first resin layer was 5.0 μm.

[0137] <Evaluation of base paper for metallized paper> The base papers for metallized paper obtained in the examples and comparative examples were evaluated as follows. [Seropic test] We thoroughly applied cellophane tape (manufactured by Nichiban Co., Ltd.) to the resin layer surface of the base paper for metallized paper, and investigated how it peeled off when it was forcefully peeled off. Note that with base paper for metallized paper that has excellent adhesion between the resin layers, and between the paper base material, clay coat layer, and resin layer, no peeling from the resin surface was observed, and the paper base material was torn. A: The paper base material was torn and peeled off over the entire surface of the cellophane tape. B: Part of the cellophane tape had torn and peeled off the paper base. C: The paper base material was not torn, and the resin layer was attached to the cellophane tape.

[0138] [Glossiness] The gloss (75° specular gloss) of the base paper for metallized paper was measured in accordance with JIS P 8142:2005 using a gloss meter (GM26-PRO / TOUCH75°, manufactured by Murakami Color Research Laboratory Co., Ltd.).

[0139] <Preparation of metallized paper> In Examples 1 to 18 and Comparative Examples 1 to 4, an aluminum vapor-deposited layer (thickness: 50 nm) was formed on the second resin layer of the base paper for the metallized paper. In Examples 1 to 16 and Comparative Examples 1 to 4, the oxygen permeability (23°C, 50% RH) of a 25 μm-thick sheet on the deposition layer was 2.0 mL / (m 2 An aqueous dispersion of a polyurethane resin binder (Mitsui Chemicals, Takelac WPB-341) was applied by Mayer bar coating and dried at 120 °C for 1 minute to form an overcoat layer (coating amount 0.5 g / m 2 Further, on the overcoat layer, an aqueous dispersion of ethylene-methacrylic acid copolymer ammonium salt (active content 35% by mass, Chemipearl S-300, manufactured by Mitsui Chemicals, Inc.) was diluted with water so that the active content was 20% by mass, and then coated with a Mayer bar and dried at 120°C for 1 minute to form a heat seal layer (coating amount 3.0 g / m 2 The thickness was 3.2 μm, and a metallized paper was obtained. In Example 17, instead of forming a heat seal layer on the overcoat layer by coating, a non-oriented polypropylene film (Rensol GP-32, 20 μm, basis weight 18 g / m, manufactured by Hokuetsu Chemical Industry Co., Ltd.) was used. 2 A polyurethane adhesive for dry lamination (DIC Corporation, DiCdry LX-500, KW-75) was applied to the overcoat layer, and a heat seal layer was formed by attaching it to the overcoat layer, thereby obtaining a vapor-deposited paper (thickness: 92.0 μm). For Example 18, a 4 μm-thick sheet was applied onto the deposition layer, and the oxygen permeability (23° C., 50% RH) was 3.0 mL / (m 2A water / alcohol solution of ethylene-vinyl alcohol copolymer resin (Ebersolve #10, manufactured by Nippon Cima Co., Ltd.) having a molecular weight of 1.0001 / day atm was applied using a Mayer bar and dried at 120 °C for 1 minute to form an overcoat layer (coating amount 0.5 g / m 2 Thereafter, a heat seal layer was formed in the same manner as in Examples 1 to 16, to obtain a metallized paper.

[0140] <Evaluation of Metallized Paper> [Heat seal peel strength] A pair of metallized papers was stacked with the heat seal layers facing each other, and heat sealed at 140°C, 0.2 MPa, and 1 second using a heat seal tester (TP-701-B, manufactured by Tester Sangyo Co., Ltd.) Subsequently, the heat-sealed test piece was cut to a width of 15 mm, and T-peeled at a tensile strength of 300 mm / min using a tensile tester, and the maximum load recorded was taken as the heat seal peel strength.

[0141] [Glossiness] The gloss (20° specular gloss) of the metallized paper was measured in accordance with JIS Z 8741:1997 using a gloss meter (GM26-PRO / TOUCH20°·60°, manufactured by Murakami Color Research Laboratory Co., Ltd.).

[0142] [Oxygen permeability] The oxygen permeability of the metallized paper was measured at a temperature of 23°C and a relative humidity of 50% in accordance with JIS K 7126-2:2006 using an oxygen permeability measuring device (OX-TRAN2 / 22, manufactured by MOCON). Specifically, an isocyanate-based adhesive (a mixture of 10 parts by mass of DIC Dry LX-500 and 1 part by mass of DIC Dry KW-75, manufactured by DIC Corporation) was applied at a rate of 5 g / m2 to the surface of the heat seal layer of the metallized paper obtained in the examples and comparative examples. 2 After coating, a 20 μm thick non-oriented polypropylene film (CPP film) (GP-32, manufactured by Hokuetsu Chemical Industry Co., Ltd.) was laminated to form a laminate sheet. The oxygen permeability of the laminate sheet was measured at a temperature of 23° C. and a relative humidity of 50% in accordance with JIS K7126-2:2006. The lower the oxygen permeability value, the better the oxygen barrier property.

[0143] [Water vapor permeability] The water vapor permeability of the metallized paper was measured in accordance with JIS Z 0208:1976 (cup method) Method B (40°C±0.5°C, relative humidity 90%±2%) with the heat seal layer facing inward (low humidity side). The lower the water vapor permeability value, the better the water vapor barrier property.

[0144] [Table 1]

[0145] [Table 2]

[0146] [Table 3]

[0147] (Table Notes) "Organic solvent content": the content of the organic solvent in the coating liquid for the resin layer. IPA: Isopropyl alcohol EtOH: Ethanol Heat seal layer of Example 17: The thickness is shown instead of the coating amount. Overcoat layer in Table 2: Polyurethane resin (Examples 10 to 17), ethylene-vinyl alcohol copolymer resin (Example 18)

[0148] As can be seen from the results in Tables 1 and 2, the metallized papers (Examples 1 to 18) made using base paper for metallized paper, which had a clay coat layer and two or three resin layers, in that order, on one side of the paper substrate, and each of the two or three resin layers had a thickness of 0.1 μm or more and 4.0 μm or less, and a total thickness of 0.2 μm or more and 5.0 μm or less, had excellent barrier properties and also excellent adhesion between the resin layers and between the resin layer and the paper substrate. In contrast, the metal-deposited papers (Comparative Examples 1 and 2) made using base papers for metal-deposited paper with one resin layer had poor barrier properties, as can be seen from the results in Table 3. Also, the metal-deposited papers (Comparative Examples 3 and 4) made using base papers for metal-deposited paper that had two resin layers but had a resin layer with a thickness of more than 4.0 μm and a total thickness of the resin layers exceeding 5.0 μm had poor adhesion between the resin layers and between the resin layer and the paper substrate.

Claims

1. A base paper for vapor deposition paper having a clay coating layer and two or more resin layers in this order on at least one surface of a paper base material, wherein the two or more resin layers have a thickness per layer of 0.1 μm or more and 4.0 μm or less, and a total thickness of 0.2 μm or more and 5.0 μm or less, the base paper for vapor deposition paper.

2. The base paper for vapor deposition paper according to Claim 1, wherein the 75° specular glossiness measured in accordance with JIS P 8142:2005 of the surface having two or more resin layers is 75.0% or more.

3. The base paper for vapor deposition paper according to Claim 1 or 2, wherein each resin layer contains a resin having a glass transition temperature of 50°C or more.

4. The base paper for vapor deposition paper according to Claim 1 or 2, wherein each resin layer contains a water-suspended polymer, and the water-suspended polymer contains one or more selected from the group consisting of polyurethane-based resins and polyester-based resins.

5. The base paper for vapor deposition paper according to Claim 1 or 2, wherein the two or more resin layers are thicker in the outermost layer than in the innermost layer.

6. A vapor deposition paper having a vapor deposition layer on two or more resin layers of the base paper for vapor deposition paper according to Claim 1 or 2.

7. The vapor deposition paper according to Claim 6, having a heat seal layer on the vapor deposition layer.

8. The vapor deposition paper according to Claim 7, having an overcoat layer between the vapor deposition layer and the heat seal layer.

9. The vapor deposition paper according to Claim 8, wherein the overcoat layer contains at least one selected from the group consisting of polyurethane-based resins, polyester-based resins, and vinyl alcohol-based resins.

10. The vapor deposition paper according to Claim 7, wherein the 20° specular glossiness measured in accordance with JIS P 8142:2005 of the surface of the heat seal layer is 40.0% or more.

11. The oxygen permeability at 23°C and 50% RH is 0.30 mL / (m ２ ·day·atm) or less, and the water vapor permeability at 40°C and 90% RH is 0.60 g / (m ２ ·day) or less, the vapor deposition paper according to claim 6.

12. The vapor deposition paper according to Claim 6, having a pigment coating layer on the opposite surface of the paper base material having the vapor deposition layer.

13. A packaging bag made using the vapor deposition paper according to Claim 6.

14. A method for manufacturing a base paper for vapor deposition paper according to Claim 1 or 2, having the following steps 1 and 2 in this order. Step 1: A step of applying and drying a coating liquid for a clay coating layer containing an inorganic pigment and a binder on at least one surface of a paper base material to form a clay coating layer Step 2: A step of applying and drying a coating liquid for a resin layer containing a water-suspended polymer on the clay coating layer to form two or more resin layers