Mount for skin pack and skin pack package

Abstract

To provide a mount for a skin pack which highly achieves both of suppression of curling in a severe environment such as a high-temperature and high-humidity environment and suppression of generation of paper powder during punching processing.SOLUTION: The mount for skin packaging has the thermoplastic-resin layer, the paper base material layer, and a protection layer in this order, the ash content in the paper base material layer of the mount for skin packaging is 1.0 to 10.0 mass%, and the weight coarseness of pulp contained in the paper base material layer is 0.045 to 0. 150mg / m.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present disclosure relates to a skin pack liner and a skin pack packaging body. [Background technology]

[0002] In the food packaging field, skin packs are used to maintain the freshness and extend the shelf life of food. The food is placed on a tray, and the tray and food are vacuum-packed using a barrier film. Skin packs, especially when used to package meat, can suppress dripping (water that escapes from food during storage), which can extend the shelf life and reduce food waste, and are therefore increasingly being used. In addition, because the food can be fixed in the center of the base material, it can be hung, allowing more products to be displayed in a small space.

[0003] Patent Document 1 discloses a skin pack mount having, in this order, a base material, a release layer containing a release agent, and an adhesive layer containing an adhesive. In Patent Document 1, the release layer allows the skin pack film to be easily peeled off. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-181075 [Patent Document 2] Patent Publication No. 2021-191690 Summary of the Invention [Problem to be solved by the invention]

[0005] Skin pack liner paper can curl in high-temperature, high-humidity environments, which can reduce operability during processing steps such as printing and film lamination. Furthermore, friction on the backside of the skin pack liner paper during punching and transportation can generate paper powder, which can adhere to the film and cause problems during food packaging. Patent Document 2 describes that a skin pack liner having a thermoplastic resin layer on one side of a paper base layer and a specific Taber stiffness can suppress curling and the generation of paper dust. However, the present inventors recognized that the effect of suppressing curling and the generation of paper dust described in Patent Document 2 may not be sufficient in some cases.

[0006] The present disclosure provides a skin pack liner that more effectively suppresses curling in harsh environments such as high-temperature, high-humidity environments, and also more effectively suppresses the generation of paper dust during punching. [Means for solving the problem]

[0007] As a result of extensive research, the present inventors have found that the above-mentioned problems can be solved by setting the ash content of the skin pack liner and the coarseness of the pulp within specific ranges in the liner, which has a thermoplastic resin layer, a paper base layer, and a protective layer in this order.

[0008] [1] A skin pack mount having a thermoplastic resin layer on at least one surface of a paper base layer, The skin pack mount has the thermoplastic resin layer, the paper base layer, and a protective layer in this order, The ash content of the skin pack mount is 1.0 to 10.0% by mass, The coarseness of the pulp contained in the paper base layer is 0.045 to 0.150 mg / m A skin pack mount characterized by: [2] The fiber orientation ratio A of the paper base layer measured from the thermoplastic resin layer side is 1.25 to 1.75, The skin pack mount according to [1], wherein the fiber orientation ratio B of the paper base layer measured from the protective layer side is 1.25 to 1.75. [3] [1] or [2], wherein the kink index of the pulp contained in the paper base layer is 3000 [1 / m] or less. [4] The mass per unit area of ​​the protective layer is 0.10 to 25.00 g / m 2 The skin pack mount according to any one of [1] to [3], [5] The skin pack mount according to any one of [1] to [4], wherein the paper base layer is a laminate consisting of a paper base layer A, an adhesive layer, and a paper base layer B from the thermoplastic resin layer side. [6] The skin pack mount according to any one of [1] to [5], wherein the protective layer contains at least one selected from the group consisting of starch and modified starch. [7] A skin pack packaging body having the skin pack mount according to any one of [1] to [6], a contained item, and a resin film, The skin pack mount has, in order from the side where the contained item is placed, the thermoplastic resin layer, the paper base layer, and the protective layer, A skin pack packaging body in which the stored item is stored between the skin pack mount and the resin film. [Effects of the Invention]

[0009] According to the present disclosure, it is possible to provide a skin pack liner that more effectively suppresses curling in harsh environments such as high-temperature, high-humidity environments, and also more effectively suppresses the generation of paper dust during punching. DETAILED DESCRIPTION OF THE INVENTION

[0010] In this specification, unless otherwise specified, the expressions "X or more and Y or less" and "X to Y" representing a numerical range mean a numerical range including the lower and upper limits, which are the endpoints. When the lower limit and upper limit of a numerical range are stated separately, the numerical range can be a combination of any lower limit and any upper limit. Furthermore, for example, a description such as "at least one selected from the group consisting of X, Y, and Z" means any of X, Y, Z, a combination of X and Y, a combination of X and Z, a combination of Y and Z, or a combination of X, Y, and Z. When X is a group, multiple Xs may be selected, and the same applies to Y and Z.

[0011] The "machine direction" refers to the machine direction (MD) of the paper substrate, which is the direction in which the fibers are oriented, and the "cross direction" refers to the direction perpendicular to the machine direction (CD).

[0012] <Skin pack mount> The skin pack liner of the present disclosure has a thermoplastic resin layer on at least one surface of a paper substrate. The inventors have found that when the skin pack liner has a thermoplastic resin layer, a paper substrate layer, and a protective layer in this order and satisfies both of the following requirements (A) and (B), it is possible to more effectively suppress curling in harsh environments such as high-temperature and high-humidity environments and to more effectively suppress the generation of paper dust during punching. Requirement (A): The ash content of the skin pack mount is 1.0 to 10.0% by mass. Requirement (B): The coarseness of the pulp contained in the paper base layer is 0.045 to 0.150 mg / m.

[0013] Each requirement is explained below. First, the skin pack liner has a thermoplastic resin layer, a paper base layer, and a protective layer in this order. The protective layer in the skin pack liner can suppress the generation of paper dust during punching and other processes.

[0014] Next, regarding requirement (A), the ash content of the skin pack liner must be 1.0 to 10.0% by mass. By keeping the ash content within this range, curling and the generation of paper dust can be suppressed. If the ash content is 1.0% by mass or more, the ash can suppress moisture expansion and contraction of the fibers of the entire paper base material, thereby suppressing curling. If the ash content is 10.0% by mass or less, the generation of paper dust can be suppressed.

[0015] Regarding requirement (B), the coarseness of the pulp contained in the paper base layer must be 0.045 to 0.150 mg / m. Coarseness is the mass of fiber per 1m. When the pulp's coarseness value is high, the fibers become rigid and the pulp is less likely to be crushed. When the pulp's coarseness value is 0.045mg / m or more, the moisture expansion and contraction of the paper base material can be reduced, and curling can be suppressed. On the other hand, when the pulp's coarseness value is low, it indicates that the pulp contains many fibers with large voids. When the pulp's coarseness value is 0.150mg / m or less, the pulp is crushed moderately, reducing the distance between fibers, allowing paper dust to be trapped between the fibers and suppressing the generation of paper dust.

[0016] As described above, by having a skin pack liner that has a thermoplastic resin layer, a paper base layer, and a protective layer in that order and satisfying both of the following requirements (A) and (B), it is possible to highly effectively suppress curling in harsh environments such as high-temperature, high-humidity environments, and to highly effectively suppress the generation of paper dust during punching.

[0017] The ash content of the skin pack mount is preferably 2.0 to 9.5% by mass, more preferably 3.0 to 8.5% by mass, and even more preferably 4.0 to 8.0% by mass. The ash content can be controlled by the amount of material that can become ash, such as calcium carbonate, added. The method for measuring the ash content will be described later.

[0018] The coarseness of the pulp contained in the paper base layer is preferably 0.045 to 0.100 mg / m, more preferably 0.055 to 0.090 mg / m, and even more preferably 0.060 to 0.080 mg / m. The coarseness of the pulp can be controlled by the type of pulp used, etc. The method for measuring the coarseness will be described later. When the paper base layer is an interleaf paper, it is preferable that the weighted average value of the coarseness according to the basis weight of each paper base layer included in the interleaf paper satisfies the above range, and it is more preferable that the coarseness of all the paper base layers included in the interleaf paper satisfies the above range. In other words, it is more preferable that the coarseness of the pulp included in each of the paper base layers in the interleaf paper satisfies the above range.

[0019] The fiber orientation ratio A of the paper base layer measured from the thermoplastic resin layer side is preferably 1.25 to 1.75, more preferably 1.25 to 1.70, and even more preferably 1.30 to 1.60. The smaller the fiber orientation ratio, the more moisture-induced expansion and contraction in the CD direction can be suppressed, making it easier to suppress curling.

[0020] The fiber orientation ratio B of the paper base layer measured from the protective layer side is preferably 1.25 to 1.75, more preferably 1.25 to 1.70, and even more preferably 1.30 to 1.60. The smaller the fiber orientation ratio, the more moisture-induced expansion and contraction in the CD direction can be suppressed, making it easier to suppress curling.

[0021] The fiber orientation ratio indicates the tendency for fibers to align in the machine direction (longitudinal direction) as the pulp slurry flows onto the wire of a paper machine, is dewatered, and forms a paper layer. In other words, the fiber orientation ratio indicates the degree of fiber orientation and is a value greater than or equal to 1. A low fiber orientation ratio indicates that the fibers are randomly oriented, while a high fiber orientation ratio indicates that the fibers are oriented in the machine direction.

[0022] The fiber orientation ratio can be controlled by adjusting the ratio between the discharge speed of the pulp-containing paper stock and the wire speed of the paper machine during papermaking of the paper base layer. This ratio is also called the J / W ratio (jet / wire ratio). Methods for increasing the fiber orientation ratio include increasing the J / W ratio.

[0023] Furthermore, the difference between fiber orientation ratio A and fiber orientation ratio B is preferably 0.30 or less. The difference between fiber orientation ratio A and fiber orientation ratio B is the absolute value of the difference. A difference in the above range indicates that the difference in fiber orientation ratio is small, and it is thought that curling can be further suppressed because the degree of shrinkage of the paper base layer due to moisture is the same for paper base layer A and paper base layer B.

[0024] There is no particular lower limit to the difference between the fiber orientation ratio A and the fiber orientation ratio B, as it is preferable that it is smaller. The difference between the fiber orientation ratio A and the fiber orientation ratio B is preferably 0.00 to 0.20, more preferably 0.00 to 0.10, and even more preferably 0.00 to 0.06.

[0025] Furthermore, it is preferable that the kink index of the pulp contained in the paper base layer is 3000 [1 / m] or less. The kink index is an index of the amount of bent fibers in the pulp fibers, and a higher kink index indicates that there are more bent fibers in the pulp fibers of the paper base layer. A kink index of 3000 [1 / m] or less indicates that there are few bent fibers, and the moisture expansion rate is small, making it easier to suppress curling. The smaller the kink index, the better, so there is no particular lower limit, but it is preferably 1700 [1 / m] or more.

[0026] The kink index of the pulp contained in the paper base layer is preferably 1700 to 3000 [1 / m], more preferably 1800 to 2500 [1 / m], and even more preferably 1900 to 2350 [1 / m].

[0027] The kink index can be controlled by the temperature when beating the pulp. The higher the temperature during beating, the smaller the kink index, making it easier to control it within the above range. It can also be controlled by the pulp consistency when beating the pulp. Specifically, the higher the pulp consistency during beating, the higher the kink index tends to be. The method for measuring the kink index will be described later. When the paper base layer is a slip sheet, it is preferable that the weighted average value of the kink index according to the basis weight of each paper base layer included in the slip sheet satisfies the above range, and it is more preferable that the kink index of all the paper base layers included in the slip sheet satisfies the above range. In other words, it is more preferable that the kink index of the pulp included in each of the paper base layers in the slip sheet satisfies the above range.

[0028] The mass per unit area of ​​the protective layer is, for example, 0.10 to 25.00 g / m 2 and 0.10 to 5.00 g / m 2 It is preferable that the density is 0.40 to 3.00 g / m 2 More preferably, it is 0.80 to 2.00 g / m 2 It is more preferable that the mass per unit area of ​​the protective layer is equal to or greater than the lower limit, thereby more sufficiently suppressing the generation of paper dust. Furthermore, the mass per unit area of ​​the protective layer is equal to or less than the upper limit, thereby making it more difficult for curling to occur.

[0029] The paper substrate layer may be a single layer, or may be a multi-layer paper substrate with adhesive layers between them. In the case of a slip sheet, the number of paper base layers is, for example, 2 to 5, preferably 2 or 3, and more preferably 2. The paper base layers are preferably a slip sheet consisting of a paper base layer A, an adhesive layer, and a paper base layer B from the thermoplastic resin layer side. When the paper base layer is an interleaf paper, the paper base layer on the thermoplastic resin layer side is referred to as paper base layer A. When the basis weight of paper base layer A is basis weight A and the basis weight of paper base layer B is basis weight B, the ratio of basis weight A to basis weight B (basis weight A / basis weight B) is preferably 2.0 to 7.0, more preferably 3.0 to 5.0. Having the ratio (basis weight A / basis weight B) in the above range can further suppress curling. Because the paper base layer A is in contact with the thermoplastic resin layer, it is less likely to absorb and release moisture than the paper base layer B. Therefore, by making the basis weight of the paper base layer A equal to or greater than that of the paper base layer B, the paper base is less susceptible to the effects of moisture, and curling can be further suppressed.

[0030] The basis weight A of the paper base layer A is preferably 200 to 1000 g / m 2 , more preferably 250 to 700 g / m 2 , and more preferably 300 to 600 g / m 2 , and even more preferably 300 to 500 g / m 2 is. The basis weight B of the paper base layer B is preferably 30 to 300 g / m 2 , more preferably 40 to 250 g / m 2 , and more preferably 50 to 200 g / m 2 , and even more preferably 60 to 150 g / m 2 is.

[0031] The basis weight of the skin pack mount is not particularly limited, but is preferably 250 to 1000 g / m 2 , more preferably 300 to 800 g / m 2 , and more preferably 350 to 700 g / m 2 is. Basis weight is measured in accordance with JIS P 8124:2011 ("Paper and paperboard -- Determination of basis weight," revised March 22, 2011). The specific procedure is described below.

[0032] The thickness of the skin pack mount is not particularly limited, but is preferably 0.30 to 0.90 mm, more preferably 0.40 to 0.85 mm, and even more preferably 0.50 to 0.80 mm. The density of the skin pack mount is not particularly limited, but is preferably 0.60 to 1.10 g / cm 3 and more preferably 0.70 to 1.00 g / cm 3 and more preferably 0.80 to 1.00 g / cm 3 is. When the thickness and density are within the above ranges, the basis weight of the skin pack mount described above is more likely to be satisfied.

[0033] The content of the paper base layer in the mount is, for example, 50 to 99% by mass, preferably 60 to 97% by mass, more preferably 70 to 95% by mass, even more preferably 80 to 93% by mass, and even more preferably 85 to 90% by mass. This range not only provides an appropriate curl suppression effect, but is also preferred from the viewpoint of reducing environmental impact.

[0034] <Paper base layer> As long as the above ash content and coarseness are satisfied, the constituent material and layer structure of the paper base layer in the skin pack liner are not particularly limited. As mentioned above, the paper base layer may be a laminated paper containing two or more paper base layers, or may be a single paper consisting of a single paper base layer.

[0035] When the paper base layer is a slip sheet, there are no particular limitations on the number of paper base layers included in the slip sheet, the lamination method of each paper base layer, the physical properties of each paper base layer, etc. The paper base layer preferably has a paper base layer A, an adhesive layer, and a paper base layer B in this order. The slip sheet having a paper base layer A, an adhesive layer, and a paper base layer B in this order may be a slip sheet consisting of only the paper base layer A, the adhesive layer, and the paper base layer B, or may be a slip sheet in which another paper layer is laminated via an adhesive layer. In this case, the paper base layer B As the other paper layer, a paper layer different from or the same as the paper base layer A may be used. Furthermore, as the other paper layer, a paper layer different from or the same as the paper base layer A or paper base layer B may be used.

[0036] As mentioned above, the fiber orientation ratio A measured from the thermoplastic resin layer side and the fiber orientation ratio B measured from the protective layer side contribute to further suppressing curling, and it is thought that the same applies when the paper base layer has three or more layers. This is because it is not the inner paper base layer that affects curling, but the paper base layer on the thermoplastic resin layer side and the protective layer side.

[0037] The paper base layer may have a single-layer structure obtained by single-layer papermaking, or a multi-layer structure obtained by multi-layer papermaking. From the viewpoint of being able to freely adjust the raw material composition, basis weight, papermaking conditions, etc. of each layer, the paper base layer preferably has a multi-layer structure. When the paper base layer has a multi-layer structure, the number of layers constituting the paper base layer is usually 2 to 10, preferably 3 to 9, more preferably 4 to 8, and even more preferably 4 to 6.

[0038] From the viewpoint of controlling the ash content in the paper base layer, it is preferable to include an ash source in the paper base layer. Examples of the ash source include at least one selected from the group consisting of calcium carbonate, talc, kaolin, titanium dioxide, silicon dioxide, etc. The ash source preferably includes calcium carbonate. The content of these ash sources may be within a range that achieves the above-mentioned ash content. For example, the content may be 1 to 20 parts by mass or 2 to 17 parts by mass per 100 parts by mass of pulp.

[0039] The ash content of the paper base material in the skin pack mount is preferably 2.0 to 12.0% by mass. The content is more preferably 3.0 to 11.0 mass %, even more preferably 4.0 to 9.0 mass %, and even more preferably 5.0 to 8.0 mass %.

[0040] The paper base layer is not particularly limited as long as it is a commonly used paper, and is preferably paper whose main component is plant-derived pulp, and more preferably paper whose main component is wood pulp. Specific examples of the paper substrate layer include kraft paper, fine paper, (white) paperboard, paper container base paper, milk carton base paper, cup base paper, liner paper, coated paper, one-side glazed paper, glassine paper, and graphene paper. Among these, the paper substrate layer is preferably a paper selected from the group consisting of kraft paper, fine paper, (white) paperboard, paper container base paper, cup base paper, and one-side glazed paper. From the perspective of rigidity, among (white) paperboard, a paper selected from the group consisting of high-quality paperboard, special paperboard, cup base paper, and kraft paper is more preferred. Examples of kraft paper include bleached kraft paper, unbleached kraft paper, and one-side glazed bleached kraft paper. Of these, from the perspective of print reproducibility and hygiene, the kraft paper is preferably a paper selected from the group consisting of bleached kraft paper and one-side glazed bleached kraft paper.

[0041] As mentioned above, the pulp constituting the paper base layer is preferably wood pulp, and more preferably kraft pulp. Kraft pulp is classified into hardwood kraft pulp (LKP) and softwood kraft pulp (NKP) based on the difference in raw materials. Hardwood kraft pulp (LKP) is preferably bleached hardwood kraft pulp (LBKP), and softwood kraft pulp (NKP) is preferably bleached softwood kraft pulp (NBKP). Furthermore, based on the difference in processing state, bleached kraft pulp (BKP), unbleached kraft pulp (UKP), and oxygen-bleached kraft pulp (OKP) are examples, and from the viewpoint of print reproducibility, bleached kraft pulp (BKP) is preferred.

[0042] Among these, the pulp is preferably one or more selected from the group consisting of hardwood kraft pulp (LKP) and softwood kraft pulp (NKP), and the hardwood kraft More preferably, it is a mixture of pulp (LKP) and softwood kraft pulp (NKP).

[0043] In the mixture, the mass ratio (LKP / NKP) of hardwood kraft pulp (LKP) to softwood kraft pulp (NKP) is not particularly limited as long as it is a ratio used in general paper, and is, for example, 50 / 50 to 100 / 0, preferably 70 / 30 to 98 / 2, and more preferably 80 / 20 to 97 / 3. By setting the mass ratio (LKP / NKP) within the above range, it becomes easier to control the coarseness within the above range.

[0044] When the paper base layer is an interleaf paper, for example, when paper base layer A and paper base layer B are used, the mass ratio (LKP / NKP) may be calculated for each paper base layer.

[0045] For example, the average fiber width of the pulp is preferably 12.0 μm to 30.0 μm, and more preferably 15.0 μm to 29.0 μm. The length-weighted average fiber length of the pulp is preferably 0.40 to 2.50 mm, and more preferably 0.50 to 2.40 mm.

[0046] The length-weighted average fiber length and average fiber width can be measured using a fiber length measuring instrument (Valmet FS-5 with UHD base unit, manufactured by Valmet Ltd.) in accordance with ISO 16065-2:2014. The instrument also uses an attached camera to detect and measure each individual fiber, capturing images within a measurement cell with a depth of field of 0.5 mm in accordance with the ISO 16505-2:2014 standard. The instrument captures images of fibers with lengths between 0.01 mm and 10.00 mm. Fibers between 0.2 mm and 7.0 mm are selected for "fiber length" and "fiber width" measurements. The average fiber width is calculated by taking the arithmetic mean of the fiber widths of all fibers measured.

[0047] The Oken smoothness (JIS P 8155:2010) of the paper base layer is preferably 5 seconds or more, more preferably 10 seconds or more and 2,000 seconds or less. From the viewpoint of print reproducibility, the 75° gloss of the paper base layer is preferably 5% or more, more preferably 10% or more and 70% or less.

[0048] (adhesive layer) When the paper base layer is a slip sheet, the adhesive layer that bonds the paper base layers, such as paper base layer A and paper base layer B, is preferably a layer made of a material with adhesive properties, and preferably contains a thermoplastic resin. By using a thermoplastic resin, slip sheets can be easily obtained by coating at least one paper base layer with a heat-melted adhesive layer and laminating the other paper base layer.

[0049] The thermoplastic resin preferably contains one or more selected from the group consisting of polyolefin-based resins, polyester-based resins, polylactic acid, styrene-based resins, and acrylic-based resins, and more preferably contains a polyolefin-based resin. Examples of polyolefin resins include polyethylene (low-density polyethylene (LDPE), medium-density polyethylene (MDPE), high-density polyethylene (HDPE), linear low-density polyethylene (LLDPE), etc.), polypropylene (PP), and polymethylpentene. Examples of polyester resins include polyethylene terephthalate and polybutylene terephthalate. Examples of the styrene resin include polystyrene, acrylonitrile styrene, and acrylonitrile butadiene styrene. Examples of acrylic resins include polymers and copolymers of acrylic monomers such as acrylic acid esters. Among these, the polyolefin resin is preferably one or more selected from the group consisting of polyethylene and polypropylene, more preferably one or more selected from the group consisting of LDPE and MDPE, and even more preferably MDPE.

[0050] The following adhesives may be used for the adhesive layer. The adhesive is not particularly limited, and may be a water-based adhesive, a solvent-based adhesive, a UV-based adhesive, or the like. Among these, the adhesive used for the adhesive layer is preferably a water-based adhesive. The water-based adhesive is preferably one or more selected from the group consisting of an acrylic adhesive, a polyurethane adhesive, and an isocyanate adhesive, and an acrylic adhesive is more preferred because of its ease of controlling adhesive strength and excellent heat resistance.

[0051] The amount of the adhesive layer per unit area is not particularly limited, but is preferably 1.0 g / m 2 More than 50.0g / m 2 or less, more preferably 1.0 g / m 2 More than 20.0g / m 2 When forming the adhesive layer, it is preferable to coat the adhesive on the paper base layer A and / or the paper base layer B so that the solid content is in this amount.

[0052] The adhesive layer may be formed as a single layer of a single resin, or as a single layer of a mixture of multiple resins, or as multiple layers of the same or different types of resins. The thickness of the adhesive layer is not particularly limited, but is preferably 5 to 100 μm, and more preferably 10 to 50 μm.

[0053] <Protective layer> The skin pack liner has a protective layer. The skin pack liner has a protective layer, which can suppress the generation of paper dust during punching and other processes. The protective layer is not particularly limited as long as it is made of a material that can suppress the generation of paper dust. The protective layer preferably contains a resin. For example, the protective layer is a resin layer.

[0054] The resin in the protective layer may be any of starches such as starch and modified starch (oxidized starch, cationized starch, esterified starch, hydrophobized starch, and dextrin); polyolefin resin (polyethylene, polypropylene, etc.), vinyl chloride resin, styrene resin, styrene / butadiene copolymer, acrylonitrile / styrene copolymer, acrylonitrile / butadiene copolymer, ABS resin, AAS resin, AES resin, vinylidene chloride resin, polyurethane resin, poly-4-methylpentene-1 resin, polybutene-1 resin, vinylidene fluoride resin, vinyl fluoride resin, fluororesin, polycarbonate resin, polya Examples of synthetic resins include amide resins, acetal resins, polyphenylene oxide resins, polyester resins (polyethylene terephthalate, polybutylene terephthalate, etc.), polyphenylene sulfide resins, polyimide resins, polysulfone resins, polyethersulfone resins, aromatic polyester resins, polyarylate resins, olefin / unsaturated carboxylic acid copolymers, styrene-acrylic copolymers (styrene / unsaturated carboxylic acid copolymers, styrene / unsaturated carboxylic acid ester copolymers), acrylic resins, polyvinyl alcohol and modified resins thereof, polyacrylic acid and salts thereof, and the like.

[0055] The protective layer preferably contains starches, that is, at least one selected from the group consisting of starch and modified starch, and more preferably contains oxidized starch. The starch raw material in the starches preferably includes at least one selected from the group consisting of corn starch, waxy corn starch, potato starch, tapioca starch, wheat starch, sweet potato starch, rice starch, etc., and more preferably includes corn starch.

[0056] The protective layer is preferably formed so as to have the above-mentioned mass per unit area. The method for forming the protective layer is not particularly limited, and known methods such as coating and lamination can be used.

[0057] In the case of the coating method, for example, a coating liquid containing an aqueous solution or emulsion in which a resin is dissolved or dispersed in water is applied to a paper substrate layer, and if necessary, some or all of the water is removed to obtain a protective layer. In this case, the coating liquid can be applied using, for example, a blade coater, air knife coater, roll coater, bar coater, gravure coater, rod blade coater, lip coater, die coater, or curtain coater. The water is preferably removed by drying with hot air or drying with infrared radiation.

[0058] In the case of lamination, the method of laminating to the paper substrate layer is not particularly limited and may be appropriately selected from known methods. For example, the paper substrate layer and the protective layer may be laminated by a thermal lamination method, a dry lamination method, a wet lamination method, an extrusion lamination method, etc. Alternatively, the protective layer and the paper substrate layer may be attached via an adhesive layer.

[0059] <Thermoplastic resin layer> The skin pack liner has a thermoplastic resin layer on at least one surface of a paper base layer. The thermoplastic resin layer protects the surface of the skin pack liner from the contents, such as food, and protects the contents from external stimuli, such as oxygen. Furthermore, for example, when the contents are sandwiched between the skin pack liner and a resin film, the thermoplastic resin layer adheres to the resin film.

[0060] The thermoplastic resin layer may be a single layer of a thermoplastic resin or a laminate containing a thermoplastic resin, but is preferably a laminate containing a barrier layer, and particularly preferably a laminate having a barrier layer between thermoplastic resin layers, such as "thermoplastic resin layer / barrier layer / thermoplastic resin layer." The thermoplastic resin layer may also be a laminate layer.

[0061] When the thermoplastic resin layer is a laminate having a barrier layer, the barrier layer is not particularly limited as long as it is a layer that can barrier oxygen and / or water vapor, and may have a single-layer structure or a multi-layer structure of two or more layers.

[0062] Specifically, the resin forming the barrier layer is preferably one or more selected from the group consisting of polyamide resins, polyvinyl alcohol, ethylene-vinyl alcohol copolymers (EVOH), and polyvinylidene chloride resins, and more preferably one or more selected from the group consisting of polyamide resins, polyvinyl alcohol, and ethylene-vinyl alcohol copolymers. The polyamide resin is preferably an aromatic polyamide, and more preferably polyamide MXD6. The barrier layer may further contain one or more other resins, such as biomass resins and biodegradable resins. Alternatively, the barrier layer may be a metal layer.

[0063] The thickness of the barrier layer is not particularly limited, but is preferably 1 to 100 μm, more preferably 3 to 50 μm, and even more preferably 5 to 30 μm.

[0064] The thermoplastic resin used in the thermoplastic resin layer is preferably one that can be laminated onto the paper substrate layer, and may be appropriately selected from known thermoplastic resins. Specifically, polyester resins such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polylactic acid, and polybutylene succinate; polyvinyl chloride, polyvinylidene chloride, polybutene, polybutadiene, ethylene vinyl acetate, Examples include polyolefin resins such as ethylene-vinyl alcohol copolymers, polyethylene, polypropylene, ethylene-vinyl alcohol copolymers, ethylene-propylene copolymers, and polymethylpentene; polycarbonate; polyurethane; polyamides such as nylon 6; polyacrylonitrile; and poly(meth)acrylate.

[0065] Among these thermoplastic resins, the thermoplastic resin used for the laminate layer is preferably one or more selected from the group consisting of polyethylene (PE) and polypropylene (PP) because of its excellent lamination and barrier properties. PE is preferably one or more selected from the group consisting of low-density polyethylene (LDPE) and medium-density polyethylene (MDPE) because of its excellent lamination properties.

[0066] The total thickness of the thermoplastic resin layer is not particularly limited, but is preferably 1 to 200 μm, more preferably 1 to 100 μm, even more preferably 5 to 50 μm, and even more preferably 10 to 40 μm.

[0067] Commercially available resin laminates (laminate films) suitable for use in the thermoplastic resin layer include a PE (polyethylene) / EVOH (ethylene-vinyl alcohol copolymer) / PP (polypropylene) film (trade name: Diamiron YF1966, 40 μm thick) manufactured by Mitsubishi Chemical Corporation, a PE (polyethylene) / EVOH (ethylene-vinyl alcohol copolymer) / PP (polypropylene) film (trade name: Diamiron MF F903, 40 μm thick) manufactured by Mitsubishi Chemical Corporation, a PP (polypropylene) / PVOH (polyvinyl alcohol) / PP three-layer film (trade name: ECO-B, 20 μm thick) manufactured by Futamura Chemical Industry Co., Ltd., a NY6 (nylon 6) / EVOH (ethylene-vinyl alcohol copolymer) / NY6 three-layer film (trade name: Heptax HP, 17 μm thick) manufactured by Gunze Limited, and a NY6 / MXD6 (polyamide MXD6) / NY6 three-layer film (trade name: Embron M, 15 μm thick) manufactured by Unitika Ltd.

[0068] (Adhesive layer) When the surface of the thermoplastic resin layer has adhesive properties, the thermoplastic resin layer may be directly adhered to the surface of the paper base layer, but it is preferable to have an adhesive layer between the paper base layer and the thermoplastic resin layer to prevent peeling during production, transportation, and display of the skin pack packaging. The adhesive constituting the adhesive layer is not particularly limited, but is preferably a resin-based adhesive suitable for dry lamination and wet lamination. Specifically, the adhesive constituting the adhesive layer can be of various types, such as water-based, solvent-based, and UV-based adhesives, among which water-based adhesives are preferred. Among the water-based adhesives, at least one selected from the group consisting of acrylic adhesives, polyurethane adhesives, and isocyanate adhesives is preferred, with acrylic adhesives being more preferred.

[0069] The amount of adhesive layer per unit area is 1 to 50 g / m 2 is preferable, and more preferably 1 to 20 g / m 2 It is preferable to coat the pressure-sensitive adhesive layer on the surface of the paper substrate layer or the surface of the thermoplastic resin layer so that the solid content is within this range. For coating, it is preferable to use a coating liquid containing the pressure-sensitive adhesive.

[0070] The thickness of the pressure-sensitive adhesive layer is not particularly limited, but from the viewpoint of moldability, it is preferably 5 μm or more and 100 μm or less, more preferably 8 μm or more and 30 μm or less.

[0071] <Other layers> The skin pack mount according to this embodiment may include other layers as long as the effects of the present disclosure are not impaired. For example, the skin pack mount may have thermoplastic resin layers on both sides. Furthermore, other layers may exist between the thermoplastic resin layers and the paper substrate layer. It may also have a laser printable layer that can be printed by printing.

[0072] (Laser printable layer) The laser printing layer is a printing layer containing titanium oxide. When the laser printing layer is irradiated with an ultraviolet laser, the titanium oxide in the printing layer changes color from white to black, and characters, patterns, etc. are printed. The discoloration of titanium oxide is thought to occur when the ionic valence of the titanium oxide contained in the printing layer changes from tetravalent to trivalent, causing oxygen defects.

[0073] The laser printing layer can be provided on the surface of the thermoplastic resin layer opposite the paper substrate layer, between the thermoplastic resin layer and the paper substrate, etc. Alternatively, the paper substrate layer may contain titanium oxide, so that the paper substrate layer also serves as the laser printing layer.

[0074] The method for forming the laser printing layer is not particularly limited, and may be a coating method or a lamination method. However, a coating method is preferred because it is easy to provide the printing layer only in the desired locations and is easy to manufacture.

[0075] The content of titanium oxide in the laser printing layer is usually 0.1 g / m from the viewpoint of obtaining sufficient printing density. 2 or more, preferably 0.2 g / m 2 More preferably, 0.3 g / m 2 More preferably, 0.4 g / m 2 From the viewpoint of obtaining a print spot with excellent print clarity, suppressing cost increases due to the inclusion of more titanium oxide than necessary when print density reaches a plateau, and suppressing the amount of smoke generated during ultraviolet laser irradiation (during printing), it is preferable that the content be 10 g / m 2 Less than 7.5 g / m 2 or less, more preferably 5 g / m 2 or less, and even more preferably 3.5 g / m 2 The following is the result.

[0076] If smoke occurs during irradiation with an ultraviolet laser, which is thought to be due to the scattering of titanium oxide, there is a risk that the discolored titanium oxide will fall off from the laser-printed layer, and if the discolored titanium oxide falls off from the laser-printed layer, the print clarity will tend to decrease. However, by setting the content of titanium oxide in the laser-printed layer to the above-mentioned upper limit or less, such smoke generation tends to be suppressed.

[0077] Furthermore, when a laser printing layer is provided between the thermoplastic resin layer and the paper base layer, the thermoplastic resin layer functions as a print protection layer, which suppresses the generation of smoke associated with ultraviolet laser irradiation and also suppresses the detachment of titanium oxide associated with the generation of smoke, and tends to result in a printed image with high print density and excellent print clarity for each point, which is even more effective.

[0078] Furthermore, for example, the skin pack mount may have a printed layer on at least one of the surfaces of the paper base layer facing the thermoplastic resin layer and the surface of the paper base layer facing the protective layer, or may have a printed layer on both surfaces (i.e., both surfaces of the skin pack mount). When the skin pack mount has a printed layer, a thermoplastic resin layer may be provided on the surface of the printed layer via an adhesive layer.

[0079] <Manufacturing method for skin pack mount> The method for producing the skin pack mount according to the present embodiment is not particularly limited, and any known method can be used. An example of the production method is shown below.

[0080] (Preparation of paper substrate layer) The method for producing a skin pack liner includes a step of obtaining a paper base layer. First, wood chips are digested to obtain the desired pulp. The wood chips may be appropriately selected depending on the desired pulp. The digestion method is not particularly limited, and known methods may be used.

[0081] Next, the pulp-containing paper stock is made into a paper base layer. The obtained paper base layer can be used as a single paper base layer. If necessary, the obtained paper base layers can be bonded together with an adhesive layer to obtain a paper base layer for an interleaving paper.

[0082] The freeness (freeness) of the pulp during papermaking is preferably 300 to 700 mL, more preferably 350 to 600 mL, and even more preferably 400 to 600 mL. The freeness here refers to the Canadian standard freeness (CSF) measured in accordance with JIS P8121:2012. Known methods can be used to beat the pulp to adjust the freeness.

[0083] From the viewpoint of controlling the kink index, the temperature during beating is preferably 30 to 70°C, more preferably 40 to 60°C, and even more preferably 45 to 55°C. Furthermore, when preparing the pulp, internal additives may be added to the pulp, such as sizing agents, fillers, paper strength agents, retention aids, pH adjusters, drainage aids, water-resistant agents, softeners, antistatic agents, antifoaming agents, slime control agents, dyes, and pigments.

[0084] From the viewpoint of controlling the ash content, as described above, calcium carbonate is preferably added to the pulp as an ash source. Other internal additives that can be used include, for example, rosin-based sizing agents, paper strength agents, aluminum sulfate, etc. The amount of paper strength agent is preferably 0.05 to 1.20 parts by mass per 100 parts by mass of pulp.

[0085] The paper base layer may contain a sizing agent. The content of the sizing agent in the paper base is preferably 0.03 to 1.20 parts by mass per 100 parts by mass of the pulp that constitutes the paper base layer. The sizing agent is not particularly limited and known sizing agents can be used. Examples of sizing agents include rosin-based sizing agents, alkyl ketene dimers, alkenyl succinic anhydrides, and styrene-containing polymers such as styrene-(meth)acrylate copolymers. The sizing agent is preferably a rosin-based sizing agent. Examples of rosin-based sizing agents include acidic papermaking sizing agents, weakly acidic papermaking sizing agents, neutral papermaking sizing agents, and reinforced rosin-based sizing agents.

[0086] The resulting pulp is optionally added with internal additives to prepare a paper stock, which is then made into paper. A known wet paper machine can be appropriately selected and used for the paper making. Examples of the paper machine include a twin-wire paper machine, a Fourdrinier paper machine, a gap former paper machine, a cylinder paper machine, and a short-wire paper machine.

[0087] The resulting paper substrate layer may be subjected to a surface treatment using a calendar to achieve uniform thickness and smoothness. A known calendaring machine can be appropriately selected and used for the calendaring treatment.

[0088] A skin pack liner can be obtained by forming a thermoplastic resin layer and a protective layer on the obtained paper base layer. When the paper base layer is a single sheet, the obtained paper base layer can be provided with a thermoplastic resin layer and a protective layer. When the paper base layer is a laminated paper, the procedure for forming the thermoplastic resin layer and the protective layer is not particularly limited. Paper base layer A and paper base layer B can be bonded together via an adhesive layer to obtain a paper base layer of laminated paper, and then a thermoplastic resin layer and a protective layer can be formed. Alternatively, a protective layer can be formed on paper base layer B, and then the paper base layer A can be bonded to the paper base layer B.

[0089] The lamination process of the paper base layer A and the paper base layer B is carried out, for example, by coating the surface of the paper base layer A or B with the resin contained in the adhesive layer that has been heated and melted, and then applying the other By laminating the paper base layer, a paper base layer that is an interleaving paper can be obtained.

[0090] Alternatively, a laminated paper substrate layer can be obtained by applying an adhesive coating solution containing an aqueous solution or emulsion in which the resin contained in the adhesive layer is dissolved or dispersed in water to the surface of the paper substrate layer A or B, removing some or all of the water as necessary, and then laminating another paper substrate layer to the coated surface. If necessary, a printing step of printing on the surface of the paper base layer or a printing layer laminating step of providing a printed layer may be performed either before or after the laminating step of each paper base layer.

[0091] (processing) The skin pack mount obtained as described above may be cut to an appropriate size taking into consideration the size and shape of the contents to be contained, and suitability for transportation and display. From the viewpoint of efficiently obtaining skin pack mounts of the same shape, cutting is preferably performed by punching. The punching process is preferably carried out using a high-speed automatic punching machine, a flat-bed punching machine, or a rotary punching machine, and more preferably a high-speed automatic punching machine. By performing punching using a high-speed automatic punching machine or a flat-bed punching machine, skin pack mounts having shapes such as a rectangle, a rounded rectangle, and an oval can be easily and efficiently obtained.

[0092] <Skin pack packaging> The present disclosure relates to a skin pack packaging body having the above-mentioned skin pack liner, a stored item, and a resin film, with the stored item being stored between the skin pack liner and the resin film. The skin pack liner has, in order from the side where the stored item is placed, a thermoplastic resin layer, a paper base layer, and a protective layer. The skin pack packaging body according to this embodiment is preferably one that hermetically stores the stored item. Skin pack packaging may be performed by a known means.

[0093] The resin film can be appropriately selected depending on the type and shape of the stored items, but preferably has excellent adhesiveness and is releasable when the stored items are removed, since it must be adhered to the thermoplastic resin layer of the skin pack mount to store the stored items. Therefore, the resin film is preferably made of the thermoplastic resin used in the thermoplastic resin layer described above, and more preferably has a barrier layer when the contents are food, etc. The barrier layer used in the thermoplastic resin layer described above is preferably used as the barrier layer.

[0094] There are no restrictions on the items that can be stored, and examples include food, daily necessities, etc., but since the items can be sealed and stored, it is preferably suitable for storing fresh foods such as vegetables, meat, fresh fish, and processed foods made from these. [Example]

[0095] The present disclosure will be explained in more detail below with reference to examples and comparative examples. The materials, amounts used, ratios, processing details, processing procedures, etc. shown in the following examples can be changed as appropriate without departing from the spirit of the present disclosure. Therefore, the scope of the present disclosure should not be interpreted as being limited by the specific examples shown below.

[0096] First, pulp was obtained by the following procedure. <Cooking> Using the wood chips listed in Table 1, cooking white liquor was prepared with a liquor ratio of 4, a sulfidity of 30%, and an effective alkali amount (as Na2O) such that the kappa number was 20 for hardwood pulp and 30 for softwood pulp. The liquor ratio is the ratio of the mass of white liquor (sodium sulfide (Na2S) + caustic soda (NaOH)) to the mass of pulp. The sulfidity is calculated by the formula: sodium sulfide concentration / {(caustic soda concentration) + sodium sulfide concentration} × 100. The resulting cooking white liquor was added to wood chips in an autoclave, and then kraft cooking was carried out at a cooking temperature of 165°C for 2 hours.

[0097] After cooking, the black liquor was separated, and the resulting pulp was defibrated using a high-consistency disintegrator, followed by three cycles of centrifugal dehydration and water washing. Undigested material was then removed using a screen, and the pulp was centrifuged to obtain unbleached hardwood or softwood pulp containing sterol ester compounds at a content of 0.012% by mass based on the bone-dry pulp mass. The hardwood pulp was then bleached using a bleaching sequence of oxygen bleaching, chlorine dioxide bleaching, alkaline peroxide bleaching, and chlorine dioxide bleaching, while the softwood pulp was bleached using a bleaching sequence of oxygen bleaching, chlorine dioxide bleaching, alkaline peroxide bleaching, peroxide bleaching, and chlorine dioxide bleaching, to obtain the bleached pulps LBKP and NBKP.

[0098] [Table 1]

[0099] Example 1 (Paper base layer A) The paper base layer A was obtained by the following procedure. 95 parts by mass of hardwood bleached kraft pulp 1 (LBKP1) and 5 parts by mass of softwood bleached kraft pulp 1 (NBKP1) were mixed and beaten at 50°C to obtain 450 mL of CSF, yielding a pulp slurry. To the resulting pulp slurry, 0.80 parts by mass (solids equivalent) of aluminum sulfate (liquid aluminum sulfate manufactured by Asahi Chemical Industries, Ltd.), 0.20 parts by mass of a polyacrylamide-based paper strength agent (Polystron 1430 manufactured by Arakawa Chemical Industries, Ltd.), 0.10 parts by mass of an internal rosin sizing agent (Sizepine N-817 manufactured by Arakawa Chemical Industries, Ltd.), and 5 parts by mass of calcium carbonate were added per 100 parts by mass of pulp solids to prepare a paper stock. Using this paper stock, the set basis weight of all five layers (surface layer, undersurface layer, middle layer, undersurface layer, and undersurface layer) was set to be equal, and the total set basis weight was 400 g / m 2 The paper was made using a five-layer short wire paper machine with the J / W ratio adjusted so that the fiber orientation ratio was 1.50±0.05, to obtain paper base layer A.

[0100] (Paper base layer B and protective layer) A paper base layer B having a protective layer formed thereon was obtained by the following procedure. 95 parts by mass of hardwood bleached kraft pulp 1 (LBKP1) and 5 parts by mass of softwood bleached kraft pulp 1 (NBKP1) were mixed and beaten at 50°C to a CSF of 450 mL to obtain a pulp slurry. To the resulting pulp slurry, 0.80 parts by mass (solids equivalent) of aluminum sulfate (liquid aluminum sulfate manufactured by Asahi Chemical Industries, Ltd.), 0.20 parts by mass of a polyacrylamide-based paper strength agent (Polystron 1430 manufactured by Arakawa Chemical Industries, Ltd.), and 0.00 parts by mass of an internal rosin sizing agent (Sizepine N-817 manufactured by Arakawa Chemical Industries, Ltd.) were added per 100 parts by mass of pulp solids. 10 parts by mass of pulp and 5 parts by mass of calcium carbonate were added to prepare a paper stock. Using this paper stock, the set basis weight of all five layers (surface layer, undersurface layer, middle layer, undersurface layer, and undersurface layer) was set to be equal, and the total set basis weight was 120 g / m 2 The paper was made using a five-layer short wire paper machine with the J / W ratio adjusted so that the fiber orientation ratio was 1.50±0.05. Furthermore, a 10% by mass aqueous solution of oxidized starch (Oji Cornstarch Co., Ltd.'s "Ace A") was applied to the surface at a solids coating amount of 1.01 g / m 2 The paper substrate layer B was then coated with a bar coater so that the protective layer was formed.

[0101] (Skin pack mount) One side of paper base layer A was melt-extrusion coated with MDPE ("8010" manufactured by ENEOS NUC Corporation) as an adhesive layer to a dry film thickness of 20 μm, and paper base layer B was laminated to the coated surface to obtain a laminate of two paper base layers and a protective layer. Then, a thermoplastic resin layer was formed on one side of a PE / EVOH / PP three-layer film (Mitsubishi Chemical Corporation's "Diamilon YF1966", film thickness 40 μm) with a coating weight of 6.0 g / m after heat drying. 2 A water-based acrylic adhesive ("Polystick EM-575" manufactured by Arakawa Paint Industries Co., Ltd.) was applied using a reverse roll coater so that the thickness of the three-layer film was 1 / 4. The paper base layer A side of the laminate obtained as described above was attached to the adhesive-coated surface of the three-layer film, and the resulting surface was dry-laminated to obtain a skin pack mount.

[0102] <Example 2> A paper base layer A was obtained in the same manner as in Example 1, except that the amount of calcium carbonate added was changed to 10 parts by mass. In addition, a paper base layer B having a protective layer formed thereon was obtained in the same manner as in Example 1, except that the amount of calcium carbonate added was changed to 10 parts by mass. The amount of the protective layer was adjusted to the values ​​shown in Table 2. Using the obtained paper base layer, a skin pack mount was obtained in the same manner as in Example 1.

[0103] Example 3 A paper base layer A was obtained in the same manner as in Example 1, except that the amount of calcium carbonate added was changed to 15 parts by mass. In addition, a paper base layer B having a protective layer formed thereon was obtained in the same manner as in Example 1, except that the amount of calcium carbonate added was changed to 15 parts by mass. The amount of the protective layer was adjusted to the values ​​shown in Table 2. Using the obtained paper base layer, a skin pack mount was obtained in the same manner as in Example 1.

[0104] Example 4 In the same manner as in Example 2, a paper base layer A was obtained. In addition, the coating amount of starch was 0.50 g / m 2 A paper base layer B having a protective layer formed thereon was obtained in the same manner as in Example 2, except for changing the above. Using the obtained paper base layer, a skin pack mount was obtained in the same manner as in Example 1.

[0105] <Example 5> In the same manner as in Example 2, a paper base layer A was obtained. In addition, the coating amount of starch was 1.52 g / m 2 A paper base layer B having a protective layer formed thereon was obtained in the same manner as in Example 2, except for changing the above. Using the obtained paper base layer, a skin pack mount was obtained in the same manner as in Example 1.

[0106] Example 6 A paper base layer A was obtained in the same manner as in Example 2, except that the J / W ratio was adjusted so that the fiber orientation ratio was 1.70±0.05. In addition, a paper base layer B having a protective layer formed thereon was obtained in the same manner as in Example 2, except that the J / W ratio was adjusted so that the fiber orientation ratio was 1.70±0.05. The amount of the protective layer was the same as that in Table 2. I made it so that. Using the obtained paper base layer, a skin pack mount was obtained in the same manner as in Example 1.

[0107] Example 7 A paper base layer A was obtained in the same manner as in Example 2, except that the J / W ratio was adjusted so that the fiber orientation ratio was 1.35±0.05. A paper base layer B with a protective layer formed thereon was obtained in the same manner as in Example 2, except that the J / W ratio was adjusted so that the fiber orientation ratio was 1.35±0.05. The amount of the protective layer was adjusted to the values ​​shown in Table 2. Using the obtained paper base layer, a skin pack mount was obtained in the same manner as in Example 1.

[0108] Example 8 A paper base layer A was obtained in the same manner as in Example 2, except that the beating temperature was changed to 45°C. In addition, a paper base layer B having a protective layer formed thereon was obtained in the same manner as in Example 2, except that the beating temperature was changed to 45° C. The amount of the protective layer was adjusted to the value shown in Table 2. Using the obtained paper base layer, a skin pack mount was obtained in the same manner as in Example 1.

[0109] Example 9 A paper base layer A was obtained in the same manner as in Example 2, except that the beating temperature was changed to 55°C. In addition, a paper base layer B having a protective layer formed thereon was obtained in the same manner as in Example 2, except that the beating temperature was changed to 55° C. The amount of the protective layer was adjusted to the value shown in Table 2. Using the obtained paper base layer, a skin pack mount was obtained in the same manner as in Example 1.

[0110] Example 10 Regarding the pulp used, a paper base layer A was obtained in the same manner as in Example 2, except that LBKP2 was used in an amount of 100 parts by mass. Regarding the pulp used, a paper base layer B having a protective layer formed thereon was obtained in the same manner as in Example 2, except that LBKP2 was used in an amount of 100 parts by mass. The amount of the protective layer was adjusted to the value shown in Table 2. Using the obtained paper base layer, a skin pack mount was obtained in the same manner as in Example 1.

[0111] Example 11 A paper base layer A was obtained in the same manner as in Example 2, except that the pulp used was changed to 95 parts by mass of LBKP3 and 5 parts by mass of NBKP2. Furthermore, regarding the pulp used, a paper base layer B with a protective layer formed thereon was obtained in the same manner as in Example 2, except that the amounts of LBKP3 and NBKP2 were changed to 95 parts by mass and 5 parts by mass, respectively. The amounts of the protective layer were adjusted to the values ​​in Table 2. Using the obtained paper base layer, a skin pack mount was obtained in the same manner as in Example 1.

[0112] Example 12 Basis weight 520g / m 2 A single-layer paper base layer was prepared in the same manner as in Example 5, except that the amount of paper stock and the pressing pressure during papermaking were adjusted so that the paper base layer was 1.51 g / m2. Oxidized starch (Oji Cornstarch Co., Ltd., "Ace A") prepared as a 10% by mass aqueous solution was applied to the surface of the paper base layer at a coating amount of 1.51 g / m2 solids. 2 The paper substrate layer was then coated with a bar coater so that the protective layer was formed. The thermoplastic resin layer was a PE / EVOH / PP three-layer film (Mitsubishi Chemical Corporation's "Diamilon YF1966", film thickness 40 μm) coated on one side with a coating weight of 6.0 g / m2 after heat drying. 2 A water-based acrylic adhesive ("Polystick EM-575" manufactured by Arakawa Paint Industries Co., Ltd.) was applied using a reverse roll coater so that the surface was smooth. The side of the three-layer film on which the protective layer was not formed was attached to the adhesive-coated side, and the surface was dry-laminated. I got a mount for Kinpack.

[0113] <Comparative Example 1> A paper base layer A was obtained in the same manner as in Example 1, except that calcium carbonate was not added. In addition, a paper base layer B having a protective layer formed thereon was obtained in the same manner as in Example 1, except that calcium carbonate was not added. The amount of the protective layer was adjusted to the values ​​shown in Table 2. Using the obtained paper base layer, a skin pack mount was obtained in the same manner as in Example 1.

[0114] <Comparative Example 2> The paper base layer was prepared in the same manner as in Example 1, except that the amount of calcium carbonate added was changed to 20 parts by mass. I got an A. In addition, the same procedure as in Example 1 was repeated except that the amount of calcium carbonate added was changed to 20 parts by mass. A paper base layer B having a protective layer formed thereon was obtained. The amount of the protective layer was adjusted to the values ​​shown in Table 2. Using the obtained paper base layer, a skin pack mount was obtained in the same manner as in Example 1.

[0115] <Comparative Example 3> In the same manner as in Example 2, a paper base layer A was obtained. Furthermore, a paper base layer B was obtained in the same manner as in Example 2, except that no starch was applied. Using the obtained paper base layer, a skin pack mount was obtained in the same manner as in Example 1.

[0116] <Comparative Example 4> A paper base layer A was obtained in the same manner as in Example 2, except that the amount of pulp used was changed to 100 parts by mass of LBKP4. Regarding the pulp used, a paper base layer B having a protective layer formed thereon was obtained in the same manner as in Example 2, except that the amount of LBKP4 was changed to 100 parts by mass. The amount of the protective layer was adjusted to the values ​​shown in Table 2. Using the obtained paper base layer, a skin pack mount was obtained in the same manner as in Example 1.

[0117] <Comparative Example 5> A paper base layer A was obtained in the same manner as in Example 2, except that the pulp used was changed to 65 parts by mass of LBKP3 and 35 parts by mass of NBKP2. Furthermore, regarding the pulp used, a paper base layer B with a protective layer formed thereon was obtained in the same manner as in Example 2, except that the amounts of LBKP3 and NBKP2 were changed to 65 parts by mass and 35 parts by mass, respectively. The amounts of the protective layer were adjusted to the values ​​in Table 2. Using the obtained paper base layer, a skin pack mount was obtained in the same manner as in Example 1.

[0118] <Comparative Example 6> A paper base layer A was obtained in the same manner as in Example 1, except that the pulp used was changed to 90 parts by mass of LBKP1 and 10 parts by mass of NBKP1, and calcium carbonate was not added. In addition, regarding the pulp used, the amount of LBKP1 was changed to 90 parts by mass and the amount of NBKP1 to 10 parts by mass, and a paper base layer B was obtained in the same manner as in Example 1, except that calcium carbonate was not added and starch was not coated. Using the obtained paper base layer, a skin pack mount was obtained in the same manner as in Example 1.

[0119] The physical properties of the skin pack mounts and paper base layers produced in the Examples and Comparative Examples were measured and evaluated by the following methods. The results are shown in Table 2.

[0120] <Basic weight> The basis weights of the skin pack liner and paper base layer were measured in accordance with JIS P 8124:2011 ("Paper and paperboard -- Determination of basis weight," revised March 22, 2011). When measuring the basis weight of the paper base layer (paper base layer A and paper base layer B in the case of an interleaf paper) from the skin pack mount, the paper base layer can be separated by the following procedure. The skin pack backing is placed in a beaker containing xylene heated to 100°C and left to stand in the xylene for 30 minutes to dissolve the thermoplastic resin. Any thermoplastic resin remaining on the surface of the paper base layer is wiped off with a cloth, and if any thermoplastic resin remains, it is immersed in xylene again and the process is repeated until the thermoplastic resin is completely removed. If the paper base layer is a laminated paper, the xylene treatment will also separate paper base layer A and paper base layer B. After the process, the xylene from the paper base layers A and B is allowed to evaporate sufficiently in a draft or similar place. Furthermore, if the protective layer contains starch, after the xylene treatment, the surface of the protective layer is immersed in water at 100°C, then in an amylase solution, and the protective layer is removed by wiping with a rag until the surface of the paper base layer is no longer slimy. The paper base layer after the above treatment is conditioned in a humidity-controlled environment as specified in JIS P 8111:1998 and then used to measure the basis weight.

[0121] <Thickness> In accordance with JISP8118:2014, the thickness of the skin pack backing paper is measured after humidity conditioning in the humidity-controlled environment specified in JISP8111:1998. The measuring device can be a paper thickness meter ("No. 132 Digital Thickness Meter" manufactured by Toyo Seiki Seisakusho Co., Ltd.) Ten points of the sample are measured, and the arithmetic average value is used.

[0122] <density> From the measured basis weight and thickness, the basis weight value (g / m 2Calculate the density using the formula: ) ÷ paper thickness (μm).

[0123] <Ash content> The ash content was measured in accordance with JIS P 8251:2003. The skin pack backing was incinerated using a muffle furnace "FO610" manufactured by Yamato Scientific Co., Ltd. The ash was quantified using a "Sartorius Cubis MSU524S" manufactured by Sartorius Japan Co., Ltd.

[0124] <Mass per unit area of ​​protective layer (amount of protective layer)> First, the type of resin in the protective layer is identified by surface analysis of the skin pack mount. The method for identifying the type of resin is not particularly limited, but for example, when the resin is starch, a method using iodine / starch reaction can be used. Next, the thermoplastic resin layer and paper substrate are removed using a grinding device (e.g., a device manufactured by Sagawa Corporation; grinding wheel dimensions: φ50.8 × 12.7 mm) so that the protective layer of the skin pack mount remains. Thereafter, the resin content is measured using the paper piece with the protective layer remaining after grinding. The method for measuring the resin content is not particularly limited, and known methods can be used. For example, when the resin is starch, the resin content can be measured by a biosensor method. More specifically, the protective layer-attached paper piece is treated with an amylase solution containing glucoamylase, and the treated solution is filtered through a filter ("Ekicrodisc 13" manufactured by Nippon Pall Corporation), and the starch concentration in the obtained filtrate is measured with a biosensor ("BF-2" manufactured by Oji Scientific Instruments Co., Ltd.), whereby the starch amount can be calculated.

[0125] In addition, when the paper strength agent and the resin in the protective layer are the same type of resin, for example, when the paper strength agent and the resin in the protective layer are both starch-based resins, the amount of resin protection is measured by the following method. First, when the paper substrate is a laminated paper, the skin pack liner is ground using a grinding device so that the protective layer and the paper layer adjacent to the protective layer remain. When the paper substrate is a monolithic paper, the skin pack liner is ground using a grinding device so that the protective layer and the monolithic paper remain. Then, after grinding, The amount of starch-based resin contained in the remaining paper piece with the protective layer is measured.

[0126] Next, if the paper substrate is an interleaf paper, the skin pack liner is ground using a grinding device so that the protective layer does not remain and only the paper layer adjacent to the protective layer remains. If the paper substrate is a single sheet, the skin pack liner is ground using a grinding device so that the protective layer does not remain and only the single sheet remains. The amount of starch-based resin contained in the paper pieces remaining after grinding is then measured. At this time, a substantially constant concentration of starch-based resin per pulp is detected near the center of the paper piece. This starch-based resin is the starch-based resin added as a paper strength enhancer to the paper substrate layer or single sheet, and it can be said that this concentration of starch-based resin is uniformly distributed throughout the entire paper substrate layer or single sheet. Using this, the amount of starch-based resin added as a paper strength enhancer to the paper layer or single sheet of the paper piece with the protective layer is calculated. The amount of resin protection is calculated by subtracting the "amount of starch-based resin added as a paper strength enhancer to the paper layer or single sheet of the paper piece with the protective layer" from the "amount of starch-based resin contained in the paper piece with the protective layer."

[0127] When the resin of the protective layer is a thermoplastic resin, for example, the amount of resin can be determined by FTIR. The amount of resin is measured by grinding the skin pack mount in the same manner as above so that the protective layer remains, obtaining a paper piece with the protective layer, and then immersing the paper layer in an enzyme such as cellulase to dissolve the paper layer, thereby measuring the weight of the resulting protective layer, and then calculating the amount of resin.

[0128] <Content ratio of paper base layer in skin pack liner> From the measured basis weights of the skin pack mount and paper base material, the basis weight of the paper base material (g / m 2 ) ÷ Basis weight of skin pack backing paper (g / m 2 The ratio of the paper substrate was calculated using the formula: ) × 100.

[0129] <Fiber orientation ratio> The fiber orientation ratio of the paper base layer is determined by measuring the ultrasonic propagation velocity in the longitudinal direction (Vmd) and the ultrasonic propagation velocity in the transverse direction (Vcd) of the paper base layer using a SONIC SHEET TESTER (SST) manufactured by Nomura Shoji Co., Ltd. The ratio (Vmd / Vcd) is then calculated as the fiber orientation ratio. Ten samples are measured, and the arithmetic average value is used. In the examples, the fiber orientation ratio A of the obtained paper substrate was measured from the thermoplastic resin side, and the fiber orientation ratio B was measured from the protective layer side. When measuring the fiber orientation ratio A and the fiber orientation ratio B from the skin pack mount, the thermoplastic resin can be removed by the above-mentioned xylene treatment before measurement.

[0130] <Coarseness and Kink Index> The coarseness and kink index of the pulp contained in the base paper are measured in accordance with ISO 16065-2: 2014. First, the thermoplastic resin layer is removed from the skin pack liner by the xylene treatment described above to obtain a paper base material. The resulting paper base layer was cut into 4 cm squares, immersed in ion-exchanged water to a solids concentration of 2% by mass, and then soaked for 24 hours. After 24 hours of soaking, the pulp was disintegrated into fibers using a standard disintegrator (manufactured by Kumagai Riki Kogyo Co., Ltd.) in accordance with JIS P8220-1:2012 until no undisintegrated fibers remained.

[0131] The disintegrated slurry is adjusted to a solids concentration of 0.1% by mass, and the pulp solids concentration is calculated in accordance with JIS P8225:2003. This is then adjusted to a solids concentration of 0.004% by mass, and 500 g of slurry is obtained, and the amount taken is recorded. The solids concentration and the amount of slurry taken are used to calculate the dry weight of the sample.

[0132] The obtained slurry is used to measure the "coarseness" and "kink index" using a fiber length measuring device (model Valmet FS-5 with UHD base unit, manufactured by Valmet). The coarseness is the gravimetric coarseness, which is the fiber coarseness measured by applying the sum of fiber lengths determined by image analysis and the dry weight of the sample input into the device.

[0133] The kink index (1 / m) referred to in this disclosure is Kibblewhite's kink index calculated by the following formula (1): The kink index is calculated by weighting the number of kinks in each angle range according to the increase in angle and dividing the weighted result by the sum of the fiber lengths. The device can detect and measure each fiber using an attached camera, capturing images within a measurement cell (flow cell) with a depth of field of 0.5 mm in accordance with the ISO 16505-2:2014 standard. The device can capture images of fibers with lengths between 0.01 mm and 10.00 mm. The pulp weight coarseness and kink index for the entire backing paper are measured from all separated paper base layers. If the paper base is a slip sheet, the coarseness and kink index of each paper base layer are measured after separation, and the weighted average values ​​according to the basis weight of the paper base layer are used as the coarseness and kink index. For example, if the paper base has paper base layer A and paper base layer B, they are calculated using the following formula. Coarseness (mg / m) when the paper substrate is interleaving paper = Coarseness of paper base layer A × (basis weight of paper base layer A / sum of basis weight of paper base layer A and basis weight of paper base layer B) + Coarseness of paper base layer B × (basis weight of paper base layer B / sum of basis weight of paper base layer A and basis weight of paper base layer B) Kink index (1 / m) when the paper substrate is a slip sheet = Kink index of paper base layer A × (basis weight of paper base layer A / sum of basis weight of paper base layer A and basis weight of paper base layer B) + Kink index of paper base layer B × (basis weight of paper base layer B / sum of basis weight of paper base layer A and basis weight of paper base layer B)

[0134]

number

[0135] The symbols in formula (1) represent the following: n1 = Number of kinks (bends) between 21° and 45° in the measurement sample n2 = Number of kinks (bends) between 46° and 90° in the measurement sample n3 = Number of kinks (bends) between 91° and 180° in the measurement sample L c = Total fiber length of the measured sample (m)

[0136] [Curl Evaluation] Each skin pack mount produced in the Examples and Comparative Examples was punched into a rectangle measuring 280 mm long x 180 mm wide. An automatic flat-plate punching machine (Carton Master AP-1300-TSG-8, manufactured by Asahi Machinery Co., Ltd.) was used for punching. The obtained sample was left to stand for 24 hours in a high-temperature, high-humidity environment (40°C, constant temperature and humidity tester PR-3KP, manufactured by Espec Corporation) at a relative humidity of 90%. The mount was then taken out into an environment with a temperature of 23°C and a relative humidity of 50%, and the curl state of the mount was checked 5 minutes later. The mount was placed flat on a horizontal hard surface, and the lifting of each of the four corners of the mount was measured, and the average value was used and evaluated according to the following criteria. When placing the mount flat on a horizontal hard surface, the paper base layer B side was placed on the hard surface and the lifting was measured. If no lifting occurred, the mount was placed flat with the paper base layer A side placed on the hard surface and the lifting was measured, and the result was used. S to B was considered good. Evaluation criteria S: The average of the four corners is less than 4 mm A: The average of the four corners is between 4mm and 7mm B: The average of the four corners is 7 mm or more and less than 10 mm C: The average of the four corners is 10 mm or more

[0137] [Paper dust evaluation] Using an automatic flat-bed die-cutter, rectangular pieces of paper measuring 280 mm in length (MD) x 180 mm in width (CD) were punched out from 100 sheets of skin pack liner (550 mm length x 800 mm width) at a rate of 6,000 sheets per hour. The last 10 skin pack liner sheets punched out were checked for the presence or absence of paper powder adhering to the thermoplastic resin layer and evaluated according to the following criteria: S to B was considered good. Evaluation criteria The number of skin pack liner sheets with paper powder attached to the thermoplastic resin layer S: 0 pieces A: 1 piece B: 2 pieces C:3 or more

[0138] [Table 2]

[0139] In Table 2, the paper base layer A in Example 12 is a paper base layer with a protective layer. In the case of a paper base layer with a protective layer, the basis weight of the paper layer excluding the protective layer is the basis weight of the paper layer. The amount of the protective layer indicates the mass per unit area of ​​the protective layer.

Claims

1. A skin pack mount having a thermoplastic resin layer on at least one surface of a paper base layer, The skin pack mount has the thermoplastic resin layer, the paper base layer, and a protective layer in this order, The ash content of the skin pack mount is 1.0 to 10.0% by mass, The skin pack liner, characterized in that the coarseness of the pulp contained in the paper base layer is 0.045 to 0.150 mg / m.

2. The fiber orientation ratio A of the paper base layer measured from the thermoplastic resin layer side is 1.25 to 1.75, The skin pack mount according to claim 1, wherein the fiber orientation ratio B of the paper base layer measured from the protective layer side is 1.25 to 1.

75.

3. 2. The skin pack liner according to claim 1, wherein the kink index of the pulp contained in the paper base layer is 3000 [1 / m] or less.

4. The mass per unit area of ​​the protective layer is 0.10 to 25.00 g / m ２ The skin pack mount according to claim 1,

5. The skin pack mount according to claim 1, wherein the paper base layer is a laminate consisting of a paper base layer A, an adhesive layer, and a paper base layer B from the thermoplastic resin layer side.

6. The skin pack liner according to claim 1, wherein the protective layer comprises at least one selected from the group consisting of starch and modified starch.

7. A skin pack packaging body comprising the skin pack mount according to any one of claims 1 to 6, a contained item, and a resin film, The skin pack mount has, in order from the side where the contained item is placed, the thermoplastic resin layer, the paper base layer, and the protective layer, A skin pack packaging body in which the stored item is stored between the skin pack mount and the resin film.

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