Mount for skin pack and skin pack package

Abstract

To provide a mount for skin pack which suppresses folding and curling even if impact due to falling is applied thereto.SOLUTION: A mount for skin pack has a thermoplastic resin layer on at least one surface of a paper base material, wherein Z-axis strength of the mount for skin pack is 280 kN / m2 or more, compressive strength in a longitudinal direction of the mount for skin pack is 23.0 kN / m or less, and Taber stiffness in the longitudinal direction of the mount for skin pack is 95.0 mN m or less.SELECTED DRAWING: None

Description

[Technical field]

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

[0002] In the field of food packaging, skin pack packaging is used to maintain the freshness and extend the shelf life of food, in which the food is placed on a tray and the tray and food are vacuum-packed using a barrier film. Skin pack packaging, particularly when used to package meat and other foods, can suppress dripping (water that escapes from food during storage), which can extend the expiration date and reduce food waste, and so is increasingly being used.

[0003] In this situation, in consideration of design based on printability and reduction of environmental load, skin pack packages have been developed in which food is placed on a paper-based mount instead of a resin tray such as polystyrene or polypropylene, and then packed with a film. Such skin pack packages have attracted attention from the viewpoint of space saving, since many products can be stored and displayed in a hanging or standing state by fixing the contents in the center of the mount. Here, when the skin pack package is stored or displayed in a hanging or standing state, the skin pack package may fall during the storage and display work, storage, or display of the skin pack package.

[0004] Therefore, Patent Document 1 proposes a multilayer film for use as a skin pack packaging base material, which has an outermost layer (a) made of a propylene-based resin, a core layer (b) made of a gas barrier resin, and an innermost layer (c) made of a heat-sealable resin selected from an ionomer, a copolymer of ethylene and a vinyl carboxylate or a (meth)acrylic acid ester, as a skin pack film resistant to the impact of being dropped. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 11-310265 Summary of the Invention [Problem to be solved by the invention]

[0006] However, even if the film has sufficient resistance to the impact of being dropped, the skin pack mount may be bent or curled.

[0007] An object of the present disclosure is to provide a mount for a skin pack that is less likely to fold or curl even when subjected to an impact from being dropped. [Means for solving the problem]

[0008] As a result of intensive research, the present inventors have found that the above problems can be solved by setting the Z-axis strength, compressive strength, and Taber stiffness of the mount within specific ranges.

[0009] [1] A skin pack mount having a thermoplastic resin layer on at least one surface of a paper substrate, The Z-axis strength of the skin pack mount is 280 kN / m 2 That's all. The skin pack mount has a longitudinal compressive strength of 23.0 kN / m or less; The Taber stiffness of the skin pack mount in the longitudinal direction is 95.0 mN·m or less. Mounting paper for skin packs. [2] The skin pack mount according to [1], wherein the ash content of the skin pack mount is 4.5% by mass or more. [3] The skin pack mount according to [1] or [2], wherein the amount (number) of fine fibers having a fiber length of 0.2 mm or less in the pulp contained in the paper base material is 5.0 to 20.0%. [4] The mount for skin packs according to any one of [1] to [3], wherein the mount for skin packs has a thickness of 450 μm to 800 μm. [5] The skin pack mount has a basis weight of 650 g / m 2 The skin pack mount according to any one of [1] to [4] below. [6] The mount for skin packs according to any one of [1] to [5], wherein the paper base material includes a paper base material layer having a multilayer structure. [7] A skin pack mount according to any one of [1] to [6], a storage item, and a resin film, A skin pack packaging body, in which the item to be contained is contained between the skin pack backing and the resin film. Effect of the Invention

[0010] According to the present disclosure, it is possible to provide a backing sheet for a skin pack that is less likely to fold or curl even when subjected to an impact from being dropped. [Brief description of the drawings]

[0011] [Figure 1] FIG. 2 is a schematic diagram illustrating a method for evaluating folds and curls of a skin pack mount. [Diagram 2] FIG. 2 is a schematic diagram illustrating a method for evaluating the strength of a skin pack mount. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] In the present disclosure, the descriptions "X to Y" and "X to Y" representing a numerical range mean a numerical range including the lower and upper limits, which are the endpoints, unless otherwise specified. When the lower limit and the upper limit of a numerical range are described separately, the numerical range can be a combination of any lower limit and any upper limit.

[0013] In this disclosure, a statement such as "one or more 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.

[0014] In this disclosure, the "machine direction" of the skin pack liner and paper substrate refers to the papermaking 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 papermaking direction (CD).

[0015] In the present disclosure, the "crease" of the skin pack mount means that the skin pack mount is creased by the impact of being dropped and is visually noticeable. Therefore, whether or not the mount is creased is judged by visual observation, as shown in the examples described later.

[0016] In the present disclosure, "curl" means that the mount is torn from the edge due to the impact of dropping, and the part is turned up. When the paper substrate has a multi-layer structure, the curl occurs mainly due to delamination of the paper substrate. On the other hand, when the paper substrate has a single-layer structure, the curl occurs mainly due to a tear in one of the layers constituting the paper substrate, and intra-layer delamination occurs. In addition, when the inter-layer strength between the paper substrate and the thermoplastic resin layer is weaker than the intra-layer strength of the paper substrate with a single layer structure or the inter-layer strength of the paper substrate with a multi-layer structure, the curl may occur due to delamination between the paper substrate and the thermoplastic resin layer.

[0017] As shown in the examples described later, the curling of the skin pack mount is evaluated by cutting out a part of the skin pack mount after a drop impact test, observing and analyzing it under a microscope, and measuring the length of the tear in the skin pack mount. For the microscope observation and analysis, for example, a laser microscope "VK-X3000 / 3100" manufactured by Keyence Corporation was used. can be used.

[0018] <Skin pack mount> The first embodiment of the present disclosure is a skin pack mount having a thermoplastic resin layer on at least one surface of a paper base material, and the Z-axis strength of the skin pack mount is 280 kN / m 2 The skin pack mount has a longitudinal compressive strength of 23.0 kN / m or less, and a longitudinal Taber stiffness of 95.0 mN·m or less. By setting the Z-axis strength, compressive strength, and Taber stiffness within the above ranges, the skin pack mount according to this embodiment can suppress the occurrence of folding and curling when subjected to an impact from being dropped.

[0019] In the past, it has been considered effective to improve the Z-axis strength in order to suppress curling due to delamination, etc. In order to improve the Z-axis, it is common to increase the press pressure during papermaking. However, the present inventors noticed that if the press pressure is increased during papermaking to increase the Z-axis strength of the skin pack mount, the compression strength increases accordingly, making it impossible to absorb the drop impact, and the impact energy is concentrated in the weak parts of the skin pack mount, making it more likely to break. Furthermore, the present inventors thought that by suppressing the Taber stiffness of the skin pack mount to a certain value or less, the mount will bend to absorb the drop impact, thereby suppressing the occurrence of breakage. Then, after investigating the Z-axis strength, compression strength, and Taber stiffness that can simultaneously suppress the occurrence of breaks and curling during a drop, they found that if all of these are adjusted within the above ranges, not only will the film be less likely to break when subjected to a drop impact, but it will also be less likely to curl. Each requirement will be described below.

[0020] (Z-axis strength of skin pack backing paper) Z-axis strength is the strength in the direction perpendicular to the paper surface. If the paper base material has a single layer structure, it is the strength of the internal bonds of the paper base material. If the paper base material has a multi-layer structure, it is the strength of the internal bonds between each layer.

[0021] The Z-axis strength of the skin pack backing is 280kN / m 2The upper limit is not particularly limited, but it is preferable that it is not too high in order to make it easier to control the compressive strength. Specifically, the Z-axis strength of the skin pack mount is preferably 280 to 550 kN / m 2 , more preferably 300 to 500 kN / m 2 More preferably, 320 to 480 kN / m 2 , particularly preferably 350 to 460 kN / m 2 It is.

[0022] By setting the Z-axis strength of the skin pack mount to the above lower limit or higher, high intralayer strength and interlayer strength can be obtained, which can suppress curling when dropped. Also, by setting the Z-axis strength of the skin pack mount to the upper limit or lower, it becomes easier to adjust the compression strength of the skin pack mount to within the range described below.

[0023] The Z-axis strength of the skin pack backing is measured in accordance with JAPAN TAPPI No. 18-1:2007 ("Paper and paperboard -- Test methods for internal bond strength -- Part 1: Z-axis tensile test method").

[0024] (Compressive strength of skin pack backing paper) The compressive strength of a skin pack liner is an index of the bond strength between the fibers that make up the paper base material, and the higher the bond strength between the fibers, the higher the compressive strength.

[0025] The compressive strength of the skin pack mount in the longitudinal direction is 23.0 kN / m or less, and although there is no particular lower limit, it is preferable that the compressive strength is a certain value or more in order to suppress curling when dropped and to make it easier to control the Z-axis strength. Specifically, the compressive strength of the skin pack mount in the longitudinal direction is preferably 13.0 to 23.0 kN / m, more preferably 14.0 to 20.0 kN / m, even more preferably 14.5 to 18.0 kN / m, and particularly preferably 15.0 to 17.0 kN / m.

[0026] By setting the longitudinal compressive strength of the skin pack mount to the above lower limit or more, sufficient intralayer strength and interlayer strength can be obtained, which can prevent curling when dropped and makes it easier to control the Z-axis strength. Also, by setting the longitudinal compressive strength of the skin pack mount to the upper limit or less, the part that receives the impact when dropped buckles and becomes like a cushion to absorb the impact, which can prevent breakage.

[0027] The horizontal compressive strength of the skin pack mount is usually smaller than the vertical compressive strength, and therefore the range of the horizontal compressive strength of the skin pack mount is not particularly limited, but is preferably 7.0 to 20.0 kN / m, more preferably 7.5 to 18.0 kN / m, even more preferably 8.0 to 15.0 kN / m, and particularly preferably 8.5 to 14.5 kN / m, from the viewpoint of suppressing curling when dropped and from the viewpoint of making it easier to control the Z-axis strength.

[0028] In addition, the geometric mean of the compressive strength in the vertical direction and the compressive strength in the horizontal direction of the skin pack mount ((compressive strength in the vertical direction × compressive strength in the horizontal direction) 1 / 2 ) is preferably 9.5 to 21.5 kN / m, more preferably 10.0 to 19.0 kN / m, still more preferably 10.5 to 16.5 kN / m, and particularly preferably 11.0 to 16.0 kN / m, from the viewpoint of suppressing curling when dropped and from the viewpoint of making it easier to control the Z-axis strength.

[0029] The compressive strength of the skin pack backing paper in the longitudinal and transverse directions is measured in accordance with JIS P 8156-2012 ("Paper and paperboard - Compressive strength test method - Short span method", established on April 20, 2012).

[0030] (Taber stiffness of skin pack backing paper) The Taber stiffness of a skin pack backing is the resistance to bending (bending load). The higher the Taber stiffness value, the stronger the material is, but the harder it is to bend when subjected to a load, i.e., the harder it is to absorb shock when dropped.

[0031] The longitudinal Taber stiffness of the skin pack mount is 95.0 mN·m or less, and although there is no particular lower limit, it is preferable that the stiffness be a certain value or more in order to provide strength to the mount. Specifically, the longitudinal Taber stiffness of the skin pack mount is preferably 49.0 to 95.0 mN·m, more preferably 55.0 to 90.0 mN·m, even more preferably 60.0 to 85.0 mN·m, and particularly preferably 65.0 to 80.0 mN·m.

[0032] By setting the longitudinal Taber stiffness of the skin pack mount to the above lower limit or more, it becomes easier to ensure a strength sufficient to withstand the weight of the packaged items. Also, by setting the longitudinal Taber stiffness of the skin pack mount to the above upper limit or less, the skin pack mount can bend and absorb the shock when dropped, making it easier to prevent the skin pack mount from breaking when dropped.

[0033] The Taber stiffness in the horizontal direction of the skin pack mount is usually smaller than that in the vertical direction. Therefore, the Taber stiffness in the horizontal direction of the skin pack mount is not particularly limited, but is preferably 25.0 to 50.0 mN·m, more preferably 28.0 to 45.0 mN·m, even more preferably 30.0 to 42.0 mN·m, and particularly preferably 35.0 to 40.0 mN·m, from the viewpoint of preventing folding when dropped while maintaining sufficient strength.

[0034] In addition, the geometric mean of the Taber stiffness in the vertical direction and the Taber stiffness in the horizontal direction of the skin pack mount ((Taber stiffness in the vertical direction × Taber stiffness in the horizontal direction) 1 / 2 ) is preferably 35.0 to 65.0 mN·m, more preferably 38.0 to 60.0 mN·m, even more preferably 42.0 to 58.0 mN·m, and particularly preferably 48.0 to 55.0 mN·m, from the viewpoint of preventing breakage when dropped while maintaining sufficient strength.

[0035] The Taber stiffness in the longitudinal and transverse directions of the skin pack backing paper is measured in accordance with JIS P 8125-2:2017 ("Paper and paperboard-Bending resistance test method-Part 2: Taber type testing machine method", enacted on March 21, 2017).

[0036] In a skin pack package, the backing is usually arranged so that the vertical direction, which has the greater strength, is the direction of fall. Therefore, the skin pack backing according to the present embodiment has a compressive strength and Taber stiffness set on the assumption that the vertical direction will be the direction of fall when the skin pack package is made by packaging the contents.

[0037] Hereinafter, a method for controlling the Z-axis strength, compressive strength, and Taber stiffness of the skin pack mount within the above ranges will be described.

[0038] As described above, in order to improve the Z-axis strength, it is common to increase the press pressure during papermaking, but increasing the press pressure increases the density of the paper and the compressive strength, so it is difficult to control the Z-axis strength and compressive strength within the above ranges by adjusting the press pressure. In addition, a method of improving the Z-axis strength by increasing the amount of paper strength enhancer added is also known, but if this method is used alone, the Z-axis strength, compressive strength, and Taber stiffness all become too high, making it difficult to control all of the Z-axis strength, compressive strength, and Taber stiffness within the above ranges. Therefore, the present inventors have investigated the content of the paper strength enhancer in the paper base material, as well as the ash content of the skin pack mount and the amount of fine fibers in the pulp in the paper base material, and have found that by adjusting the content of one or more of these, it is possible to easily control all of the Z-axis strength, compressive strength, and Taber stiffness within the above ranges.

[0039] The ash content of the skin pack mount has the effect of suppressing the increase in compressive strength and Taber stiffness that occurs with the improvement of Z-axis strength. Therefore, by adjusting the ash content of the skin pack mount within a specific range, the cushioning properties of the skin pack mount are improved and it becomes easier to absorb the impact of being dropped, so that the occurrence of breakage when dropped can be effectively suppressed.

[0040] The ash content relative to the total mass of the skin pack mount is preferably 4.5% by mass or more, and although there is no particular upper limit, if it is too high, it may adversely affect operability, so it is preferably below a certain value. Specifically, the ash content of the skin pack mount is preferably 4.5 to 20.0% by mass, more preferably 5.0 to 18.0% by mass, even more preferably 6.0 to 17.0% by mass, and particularly preferably 6.5 to 15.0% by mass.

[0041] The ash content of the skin pack liner can be easily controlled by adjusting the content of inorganic fillers commonly used in the papermaking field. Examples of inorganic fillers include ground calcium carbonate, light calcium carbonate, clay, calcined kaolin, delaminated kaolin, light calcium carbonate-silica composite, magnesium carbonate, barium carbonate, titanium dioxide, zinc oxide, acid Examples of the hydroxide include silicon dioxide, amorphous silica, aluminum hydroxide, calcium hydroxide, magnesium hydroxide, and zinc hydroxide.

[0042] The ash content of the skin pack backing paper is measured in accordance with JIS P 8251:2003.

[0043] The fine fibers in the paper base material penetrate into the gaps between the pulp fibers to increase the number of bonding points between the fibers, improving the Z-axis strength and Taber stiffness, and suppressing the occurrence of breakage and curling when dropped. Furthermore, according to the present method of controlling the amount of fine fibers in the pulp in the paper base material, the impact on the compressive strength and Taber stiffness is smaller than that of the method of improving the Z-axis strength by adjusting the press pressure during papermaking, so the Z-axis strength, compressive strength, and Taber stiffness of the skin pack liner can be easily controlled within the above ranges. In the present disclosure, the term "fine fibers" refers to fibers having a fiber length of 0.2 mm or less.

[0044] The amount (number) of fine fibers in the pulp contained in the paper base material is preferably 5.0 to 20.0%, more preferably 6.0 to 19.0%, still more preferably 7.0 to 18.0%, and particularly preferably 8.0 to 17.0%.

[0045] The amount of fines was measured using a fiber length measuring instrument (e.g. Valmet's New Valmet FS5 laboratory pulp analyzer with UHD image analysis unit) according to ISO 16065-2:2014 ("Pulp - Determination of fiber length by automated optical analysis - Part 2: Non-polarized method"). The fiber length is calculated from the results of the measurement, which is performed by taking pictures in a measurement cell with a depth of field of 0.5 mm in accordance with the "Fiber Length Measurement Method" (issued on January 15, 2007). A more specific measurement procedure will be explained in the Examples section.

[0046] The strength enhancer in the paper base material is a component that increases the number of bond points between fibers, thereby improving the intralayer strength and interlayer strength. Therefore, by adjusting the content of the strength enhancer in the paper base layer, the Z-axis strength, compressive strength, and Taber stiffness of the skin pack liner can be improved. The strength enhancer may be contained in one of the paper base layers that make up the paper base material, or may be contained in two or more paper base layers. In addition, the strength enhancer may be applied between each layer during papermaking by multi-layer papermaking, as described below, and may be contained between each layer of the paper base layer by combining the layers.

[0047] Examples of the paper strength agent in the paper base material include starch, cationic starch, polyacrylamide, polyamide amino epichlorohydrin, etc., and preferably one or more selected from the group consisting of starch and cationic starch.

[0048] The content of the paper strength agent in the paper base material varies depending on the type of paper strength agent and the desired Z-axis strength, but is preferably 0.10 to 1.00 mass %, more preferably 0.15 to 0.75 mass %, even more preferably 0.20 to 0.70 mass %, and particularly preferably 0.20 to 0.60 mass %, in one paper base layer contained in the paper base material.

[0049] (Thickness of skin pack backing paper) The thickness of the skin pack mount is not particularly limited, but is preferably 450 to 800 μm, more preferably 500 to 750 μm, even more preferably 550 to 720 μm, and particularly preferably The average thickness is 600 to 700 μm.

[0050] By making the thickness of the skin pack mount at or above the lower limit, the cushioning properties are improved and the shock of being dropped can be easily absorbed, so that the occurrence of folding when dropped can be more effectively prevented. Also, by making the thickness of the skin pack mount at or below the upper limit, the stiffness does not become too high, so that the occurrence of folding when dropped can be sufficiently prevented.

[0051] The thickness of the skin pack backing paper is measured in accordance with JIS P 8118:2014 ("Paper and paperboard -- Test methods for thickness, density and specific volume", revised on November 20, 2014). The thickness of 10 samples is measured, and the arithmetic mean value is adopted as the thickness of the paper base layer. When the skin pack mount has layers other than paper, such as an adhesive layer and a thermoplastic resin layer described below, the thickness of each layer is measured from an observation image of the cross section of the skin pack mount under an electron microscope (SEM), and the thickness of the skin pack mount is calculated from the measurement results. In other words, when the skin pack mount has layers other than paper, such as an adhesive layer and a thermoplastic resin layer described below, the thickness of the skin pack mount includes the thickness of those layers.

[0052] (Skin pack backing paper basis weight) The basis weight of the skin pack mount is not particularly limited, but is preferably 450 to 650 g / m 2 , more preferably 480 to 620 g / m 2 , and more preferably 500 to 600 g / m 2 , particularly preferably 550 to 600 g / m 2 It is.

[0053] By setting the basis weight of the skin pack mount to the lower limit or more, sufficient Z-axis strength and Taber stiffness can be ensured, and the occurrence of folding and curling when dropped can be suppressed. Also, by setting the basis weight of the skin pack mount to the upper limit or less, the compressive strength does not become excessively high, and the occurrence of folding when dropped can be suppressed.

[0054] The basis weight of the skin pack liner is measured in accordance with JIS P 8124:2011 ("Paper and paperboard -- Determination of basis weight", revised on March 22, 2011).

[0055] (Density of skin pack backing paper) The density of the skin pack mount is the value obtained by dividing the basis weight by the thickness, and is not particularly limited, but is preferably 0.650 to 1.000 g / cm 3 , more preferably 0.700 to 0.950 g / cm 3 , and more preferably 0.750 to 0.900 g / cm 3 , particularly preferably 0.800 to 0.900 g / cm 3 It is.

[0056] By setting the density of the skin pack mount to the above lower limit or more, sufficient Z-axis strength and Taber stiffness can be ensured, and the occurrence of folding and curling when dropped can be suppressed. Also, by setting the density of the skin pack mount to the above upper limit or less, it becomes easier to control the compressive strength and Taber stiffness within suitable ranges, and the occurrence of folding when dropped can be effectively suppressed.

[0057] (Paper base material) The skin pack mount according to the present embodiment is not particularly limited in terms of the constituent material and layer structure of the paper base material, as long as it satisfies the above Z-axis strength, compressive strength, and Taber stiffness. The paper base material may be a slip sheet containing two or more paper base layers, or a single paper consisting of one paper base layer, but in terms of ease of control of the Z-axis strength, compressive strength, and Taber stiffness, it is preferable that the paper base material is a slip sheet having a multilayer structure, a single paper consisting of a paper base layer having a multilayer structure obtained by multilayer papermaking, or a slip sheet containing a paper base layer having a multilayer structure obtained by multilayer papermaking.

[0058] When the paper substrate is a slip sheet, the number of paper substrate layers included in the slip sheet, the lamination method of each paper substrate layer, the physical properties of each paper substrate layer, etc. are not particularly limited. The paper substrate is preferably a paper substrate layer A and an adhesive layer. and a paper base layer B in this order. The interleaf paper having a paper base layer A, an adhesive layer, and a paper base layer B in this order may be an interleaf paper consisting of only the paper base layer A, the adhesive layer, and the paper base layer B, or may be an interleaf paper in which another paper layer is laminated via an adhesive layer. In this case, the same paper layer as the paper base layer A may be used as the paper base layer B. Also, the same paper layer as the paper base layer A or the paper base layer B may be used as the other paper layer.

[0059] The paper substrate is preferably a laminate having, in order from the surface in contact with the thermoplastic resin layer, a paper substrate layer A, an adhesive layer, and a paper substrate layer B. The paper substrate may further have other paper substrate layers as long as the effects of the present disclosure are not impaired. The constituent materials and layer configurations of the paper substrate layer A and the paper substrate layer B (hereinafter sometimes simply referred to as "paper substrate layers") are not particularly limited. Of the paper base layers, the one in contact with the thermoplastic resin layer is referred to as paper base layer A, but the thermoplastic resin layers may be provided on both sides of the paper base. In that case, the paper base layer with the larger basis weight is referred to as paper base layer A. If the basis weights are the same, one of them is referred to as paper base layer A and the other is referred to as paper base layer B.

[0060] The paper base layer may be a single-layer paper base layer made by single-layer papermaking, or a multi-layer paper base layer made by multi-layer papermaking. The paper base layer preferably has a multi-layer structure from the viewpoint of easily controlling the Z-axis strength, compressive strength, and Taber stiffness, and from the viewpoint of arbitrarily adjusting the raw material composition, basis weight, and papermaking conditions of each layer. 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.

[0061] 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.

[0062] Specific examples of the paper base layer include kraft paper, fine paper, (white) paperboard, base paper for paper containers, milk carton base paper, cup base paper, liner paper, coated paper, one-sided gloss paper, glassine paper, and graphene paper. Among these, the paper base layer A and the paper base layer B are preferably selected from the group consisting of kraft paper, fine paper, (white) paperboard, base paper for paper containers, cup base paper, and one-sided gloss paper, and from the viewpoint of rigidity, among the (white) paperboards, it is more preferable that the paper be selected from the group consisting of high-grade paperboard, special paperboard, cup base paper, and kraft paper. Examples of the kraft paper include bleached kraft paper, unbleached kraft paper, and one-sided gloss bleached kraft paper. Among these, the kraft paper is preferably selected from the group consisting of bleached kraft paper and one-sided gloss bleached kraft paper from the viewpoint of printability and hygiene.

[0063] As described above, the pulp constituting the paper base layer is preferably wood pulp, and more preferably kraft pulp. Kraft pulp includes hardwood kraft pulp (LKP) and softwood kraft pulp (NKP) based on the difference in raw materials. As hardwood kraft pulp (LKP), hardwood bleached kraft pulp (LBKP) is preferable, and as softwood kraft pulp (NKP), softwood bleached kraft pulp (NBKP) is preferable. In addition, as the difference in processing state, bleached kraft pulp (BKP), unbleached kraft pulp (UKP), and oxygen bleached kraft pulp (OKP) are mentioned, and from the viewpoint of printability, bleached kraft pulp (BKP) is preferable.

[0064] 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 more preferably a mixture of hardwood kraft pulp (LKP) and softwood kraft pulp (NKP). 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. Without limitation, the ratio is preferably 1 / 99 to 99 / 1, more preferably 30 / 70 to 99 / 1, further preferably 40 / 60 to 99 / 1, particularly preferably 50 / 50 to 95 / 5, and most preferably 60 / 40 to 95 / 5. When the pulp is made of hardwood kraft pulp (LKP) and / or softwood kraft pulp (NKP), the content of hardwood kraft pulp (LKP) relative to the total amount of pulp is usually 0 to 100% by mass, preferably 1 to 99% by mass, more preferably 30 to 99% by mass, even more preferably 40 to 99% by mass, particularly preferably 50 to 95% by mass, and most preferably 60 to 95% by mass, while the content of softwood kraft pulp (NKP) relative to the total amount of pulp is usually 0 to 100% by mass, preferably 1 to 99% by mass, more preferably 1 to 70% by mass, even more preferably 1 to 60% by mass, particularly preferably 5 to 50% by mass, and most preferably 5 to 40% by mass. In addition, the fine fibers contained in the pulp are preferably fine fibers of hardwood kraft pulp (LKP).

[0065] 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 1,000 seconds or less. From the viewpoint of printability, the 75° gloss of the paper base layer is preferably 5% or more, more preferably 10% or more and 70% or less.

[0066] The basis weight, thickness, and density of the paper base layer are preferably within the ranges that allow the basis weight, thickness, and density of the skin pack mount to be adjusted within the above-mentioned ranges, and the specific values ​​are as follows:

[0067] The basis weight of the paper base layer A is preferably 300 to 1,000 g / m 2 , more preferably 350 to 900 g / m 2 , and more preferably 400 to 800 g / m 2 It is. The thickness of the paper base layer A is preferably 300 to 1,200 μm, more preferably 400 to 1,000 μm, and even more preferably 450 to 800 μm. The density of the paper base layer A is preferably 0.500 to 1.200 g / cm 3, more preferably 0.700 to 1.000 g / cm 3 It is.

[0068] The basis weight of the paper base layer B is preferably 50 to 400 g / m 2 , more preferably 60 to 360 g / m 2 , and more preferably 70 to 240 g / m 2 It is. The thickness of the paper base layer B is preferably 50 to 600 μm, more preferably 60 to 400 μm, and even more preferably 70 to 200 μm. The density of the paper base layer B is preferably 0.500 to 1.200 g / cm 3 , more preferably 0.700 to 1.000 g / cm 3 It is.

[0069] The basis weight, density and thickness of the paper base layer are measured by the same methods as those for the basis weight, density and thickness of the skin pack mount, respectively.

[0070] In addition, it is preferable that the basis weight of the paper base layer A and the basis weight of the paper base layer B satisfy the relationship of basis weight of paper base layer A ≧ basis weight of paper base layer B. Since 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 the basis weight of the paper base layer B, the paper base is less susceptible to the effects of moisture, and curling can be suppressed.

[0071] When the pulp in the paper base material contains fine fibers, the fine fibers may be contained in either the pulp constituting paper base layer A or the pulp constituting paper base layer B, or may be contained in both, but it is preferable that the fine fibers are contained in at least the pulp constituting paper base layer A.

[0072] The amount (number) of fine fibers contained in the pulp constituting the paper base layer may be appropriately selected so that the amount of fine fibers in the pulp contained in the entire paper base layer falls within the above-mentioned range, and preferably is 5.0 to 25.0%, more preferably 10.0 to 20.0%.

[0073] When the paper base layer is a single sheet, the above-mentioned paper base layer A is preferably used as the single sheet.

[0074] (adhesive layer) The adhesive layer that bonds the paper base layer A and the paper base layer B may be a layer made of a material having adhesive properties, but preferably contains a thermoplastic resin. By using a thermoplastic resin, it is possible to easily obtain an interleaving paper by coating at least one of the paper base layers with a heat-melted adhesive layer and laminating the other paper base layer.

[0075] The thermoplastic resin preferably contains one or more resins 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.

[0076] 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), polymethylpentene, etc. Among these, from the viewpoints of extrusion lamination properties and ease of application to the paper base layer, it is more preferable to use one or more types selected from the group consisting of LDPE and MDPE, and more preferably MDPE.

[0077] Examples of polyester resins include polyethylene terephthalate and polybutylene terephthalate.

[0078] Examples of the styrene-based resin include polystyrene, acrylonitrile styrene, and acrylonitrile butadiene styrene.

[0079] Examples of the acrylic resin include acrylic acid ester polymers.

[0080] The following adhesives may be used as 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 in 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 is more preferably an acrylic adhesive in terms of ease of control of adhesive strength and excellent heat resistance.

[0081] 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 Less than 1.0 g / m, 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.

[0082] The adhesive layer may be formed as a single layer of a single resin, or may be formed as a single layer of a mixture of multiple resins, or may be formed as multiple layers made of the same or different types of resins. The thickness of the adhesive layer is not particularly limited, but is preferably 1 to 100 μm, and more preferably 5 to 50 μm.

[0083] (thermoplastic resin layer) The skin pack mount has a thermoplastic resin layer on at least one surface of a paper base material. The paper base material layer in contact with the thermoplastic resin layer is paper base material layer A. The thermoplastic resin layer is It has the role of protecting the surface of the paper from the stored items such as food, and protecting the stored items from external stimuli such as oxygen, etc. In addition, for example, when the stored items are sandwiched between the skin pack mount and a resin film, the thermoplastic resin layer has the role of adhering to the resin film.

[0084] 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 is 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.

[0085] 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 be a layer of a single layer structure or a layer of a multilayer structure of two or more layers.

[0086] Specifically, the resin forming the barrier layer is preferably one or more selected from the group consisting of polyamide resins, polyvinyl alcohol (PVOH), 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. As the polyamide resin, aromatic polyamide is preferable, and polyamide MXD6 is more preferable. 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.

[0087] The thickness of the barrier layer is not particularly limited, but is preferably 1 to 100 μm, more preferably 3 to 50 μm, and further preferably 5 to 30 μm.

[0088] The thermoplastic resin used in the thermoplastic resin layer is preferably one that can be laminated to the paper base layer. The thermoplastic resin may be appropriately selected from known thermoplastic resins.

[0089] Examples of known thermoplastic resins include polyester-based resins such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polylactic acid, and polybutylene succinate; polyolefin-based resins such as polyvinyl chloride, polyvinylidene chloride, polybutene, polybutadiene, ethylene-vinyl acetate copolymer, polyethylene, polypropylene, ethylene-propylene copolymer, and polymethylpentene; polycarbonate; polyurethane; polyamides such as nylon 6; polyacrylonitrile; and poly(meth)acrylate.

[0090] Among these thermoplastic resins, the thermoplastic resin is preferably one or more selected from the group consisting of polyethylene (PE) and polypropylene (PP) because of its excellent extrusion lamination properties and barrier properties. In addition, the 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 extrusion lamination properties.

[0091] 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.

[0092] Commercially available resin laminates (laminated films) suitable for use in the thermoplastic resin layer include a three-layer film (product name: ECO-B, film thickness 20 μm) of PP (polypropylene) / PVOH (polyvinyl alcohol) / PP manufactured by Futamura Chemical Industry Co., Ltd., and a three-layer film (product name: NY6 (nylon 6) / EVOH (ethylene-vinyl alcohol copolymer) / NY6 manufactured by Gunze Co., Ltd. Examples include a film (product name: Heptax HP, thickness 17 μm) manufactured by Unitika Ltd., and a three-layer film of NY6 / MXD6 (polyamide MXD6) / NY6 (product name: Embron M, thickness 15 μm) manufactured by Unitika Ltd.

[0093] (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 substrate. However, in order to prevent peeling during production, transportation, and display of the skin pack packaging, it is preferable to have an adhesive layer between the paper substrate and the thermoplastic resin layer.

[0094] 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 may be of a water-based, solvent-based, UV-based, or other type, and among these, a water-based adhesive is preferred. Among the water-based adhesives, at least one selected from the group consisting of an acrylic adhesive, a polyurethane adhesive, and an isocyanate adhesive is preferred, and an acrylic adhesive is more preferred.

[0095] The amount of adhesive layer per unit area is 1 to 50 g / m 2 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 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, and it is more preferable to use a mixed coating liquid in which a curing agent is mixed into a coating liquid containing the pressure-sensitive adhesive.

[0096] The thickness of the pressure-sensitive adhesive layer is not particularly limited, but from the viewpoint of moldability, it is preferably 5 to 100 μm, more preferably 8 to 30 μm.

[0097] (other layers) The skin pack mount according to the present embodiment may have other layers as long as the effects of the present disclosure are not impaired. For example, the skin pack mount may have a printed layer made of ink formed by offset printing on one or both sides of a paper substrate. When the skin pack mount has a printed layer, it is preferable to provide a thermoplastic resin layer on the surface of the printed layer via an adhesive layer.

[0098] <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 method such as a known method or a method similar thereto can be used. An example of the production method is shown below.

[0099] (Preparation of paper substrate) First, a paper base layer having a single layer or multi-layer structure is obtained by single-layer or multi-layer papermaking of a paper material containing pulp. The obtained paper base layer can be used as a paper base material as a single sheet. The paper base layer can also be used as a paper base material as an interleaving paper by bonding the paper base layer with an adhesive layer as necessary.

[0100] When a specific amount of fine fibers is to be contained in the pulp, it is preferable to add fine fibers obtained by pulping hardwood kraft pulp such as bleached hardwood kraft pulp with a known pulverizing device such as a cutter mill when preparing the pulp, since this makes it easier to control the amount of fine fibers in the pulp.

[0101] During the preparation of the pulp, it is preferable to add the above-mentioned inorganic filler to the pulp. Since the majority of the ash content of the skin pack backing paper is derived from the inorganic filler in the paper base material, By adjusting the content of the inorganic filler, it becomes possible to more easily control the ash content of the skin pack mount.

[0102] When preparing the pulp, internal additives other than the inorganic fillers may be added to the pulp, such as sizing agents, fillers, paper strength agents, retention aids, pH adjusters, drainage improvers, water resistance agents, softeners, antistatic agents, defoamers, slime control agents, dyes, and pigments.

[0103] For example, a rosin-based sizing agent, a paper strength agent, aluminum sulfate, etc. can be used. The amount of the rosin-based sizing agent is preferably 0.05 to 0.50 parts by mass relative to 100 parts by mass of pulp. The amount of the paper strength agent is preferably 0.05 to 0.50 parts by mass relative to 100 parts by mass of pulp.

[0104] The obtained pulp is added with an internal additive as necessary to obtain a paper stock, which is then made into paper. In the paper making process, a known wet paper machine can be appropriately selected and used. Examples of the paper machine include a twin wire paper machine, a fourdrinier paper machine, a gap former type paper machine, a cylinder paper machine, and a short wire paper machine.

[0105] In papermaking, for example, a method can be used in which a paper stock is cast onto a wire or the like, dehydrated to obtain a wet paper, and multiple wet papers are stacked as necessary, and this single-layer or multi-layer wet paper is pressed and dried. In this case, if multiple wet papers are not stacked, a single-layer base paper is obtained, and if multiple wet papers are stacked, a multi-layer base paper is obtained. When a multi-layer base paper is obtained, the above-mentioned paper strength agent may be applied between each layer during papermaking to increase the interlayer strength, and the layers may be stacked together.

[0106] When applying the adhesive component, the amount of the adhesive component (e.g., the amount of coating after drying) is 0.10 to 5.00 g / m 2 It is preferable that the thickness is 0.40 to 2.00 g / m 2 It is more preferable that:

[0107] The paper produced by the papermaking machine is preferably transported on a felt and dried in a dryer. A multi-stage cylinder dryer may be used as a pre-dryer before drying in the dryer.

[0108] The obtained paper may be surface-treated by calendaring to make the thickness and profile uniform. For the calendaring, a known calendaring machine can be appropriately selected and used.

[0109] When the paper base material is a single sheet, the obtained paper base material layer can be used as the paper base material and a thermoplastic resin layer can be provided to obtain a skin pack mount.

[0110] When the paper base material is a slip sheet, there is no particular restriction on the procedure for forming the skin pack liner after obtaining the paper base material layer A and the paper base material layer B. The paper base material layer A and the paper base material layer B may be bonded together via an adhesive layer to obtain a paper base material, and then a thermoplastic resin layer may be provided to obtain the skin pack liner. The skin pack liner may be obtained by providing a thermoplastic resin layer on the paper base material layer A, and providing an adhesive layer and the paper base material layer B on the side of the paper base material layer A opposite to the side in contact with the thermoplastic resin layer, thereby obtaining the skin pack liner.

[0111] It is preferable to first carry out the lamination step of the paper base layer A and the paper base layer B. For example, the surface of one of the paper base layers can be coated with the resin contained in the heat-melted adhesive layer, and the other paper base layer can be laminated to the coated surface to obtain a paper base that is a laminate.

[0112] Alternatively, a paper substrate layer as a laminate can be obtained by applying an adhesive coating liquid 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 one of the paper substrate layers, removing some or all of the moisture as necessary, and laminating the other paper substrate layer on the applied surface. In this case, for example, a blade coater, an air knife coater, a roll coater, a bar coater, a gravure coater, a rod blade coater, a lip coater, a die coater, or a curtain coater can be used as a method for applying the adhesive coating liquid. For removing moisture, it is preferable to use drying with hot air or drying with infrared radiation. If necessary, a printing step of printing on the surface of the paper base layer or a printing layer lamination step of providing a printed layer may be performed either before or after the lamination step of each paper base layer.

[0113] (Formation of Thermoplastic Resin Layer) When a thermoplastic resin layer is provided on one or both surfaces of the paper substrate, the thermoplastic resin layer may be directly adhered to the paper substrate, or may be adhered to the paper substrate via an adhesive layer. In the latter case, it is preferable to apply a coating liquid containing an adhesive onto the surface of the paper substrate, and then laminate the thermoplastic resin layer onto the surface of the paper substrate via the adhesive layer. In this case, a film may be attached to the paper substrate as the thermoplastic resin layer.

[0114] (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 stored, 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 carrying out the punching process 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, an ellipse, and the like can be easily and efficiently obtained.

[0115] <Skin pack packaging> A second embodiment of the present disclosure is a skin pack package having the above-mentioned skin pack mount, a stored item, and a resin film, with the stored item being stored between the skin pack mount and the resin film. The skin pack package according to this embodiment is preferably one that hermetically stores the stored item.

[0116] The resin film can be appropriately selected depending on the type and shape of the stored item, but preferably has excellent adhesiveness and is peelable when the stored item is removed, since it needs to be adhered to the thermoplastic resin layer of the skin pack mount to store the stored item. Therefore, the resin film is preferably made of the thermoplastic resin used in the above-mentioned thermoplastic resin layer, and more preferably has a barrier layer when the contents are food, etc. As the barrier layer, the barrier layer used in the above-mentioned thermoplastic resin layer is preferably used.

[0117] When the skin pack packaging according to the present embodiment is hung for display, the skin pack packaging is provided with a hanging part. The hanging part is not particularly limited as long as it allows the skin pack packaging to be hung from a hanging rod, and may be, for example, a through hole opened in the skin pack packaging so that the skin pack packaging can be passed through a hanging rod, a part of the skin pack packaging cut into a hook shape so that the skin pack packaging can be hung on a hanging rod, or a hanging tool such as a hook and a suction cup attached to the skin pack packaging.

[0118] There is no limitation on the stored items, and examples of the stored items include food and daily necessities. However, the stored items are preferably Since it can be sealed and stored, it is suitable for storing fresh foods such as vegetables, meat, and fish, as well as processed foods made from these foods. EXAMPLES

[0119] The present disclosure will be described 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 disclosure. Therefore, the scope of the present disclosure should not be interpreted as being limited by the specific examples shown below.

[0120] [Preparation of Paper Base Layer A-1] Pulp slurry was obtained by mixing 85 parts by mass of hardwood bleached kraft pulp (LBKP) beaten to 450 mL Canadian Standard Freeness (CSF), 5 parts by mass of softwood bleached kraft pulp (NBKP) beaten to 500 mL CSF, and 10 parts by mass of fine fibers. The fine fibers were obtained by mechanically crushing a dry sheet of LBKP with a cutter mill (HORAI Corporation, "HA8 2542 30E"; screen 0.24 mm) and then separating the fraction with a pulp fiber length of 0.2 mm or less using a fiber classifier (Aikawa Iron Works, Inc., "MAX-F700"). To 100 parts by mass (converted into pulp solids) of the obtained pulp slurry, 0.80 parts by mass (converted into solids) of aluminum sulfate (liquid aluminum sulfate manufactured by Asahi Chemical Industry Co., Ltd.), 5.0 parts by mass of calcium carbonate, and 0.20 parts by mass of cationized starch ("Kate F" manufactured by Oji Cornstarch Co., Ltd.) were added to prepare five layers of paper stock for the top layer, the underside layer, the middle layer, the underside layer, and the underside layer. Using this paper stock, paper was made on a five-layer short-wire papermaking machine with the same set basis weight for all five layers. When the layers were overlapped, 2.00 g / m of cationized starch was added between each layer. 2 In addition, by adjusting the press thickness during papermaking, the basis weight was 450 g / m 2 Thus, a paper base layer A-1 having a thickness of 528 μm was obtained.

[0121] [Preparation of Paper Base Layer A-2] A paper base layer A-2 was obtained in the same manner as the paper base layer A-1, except that the amount of cationic starch added to the pulp slurry when preparing the paper stock was changed to 0.40 parts by mass.

[0122] [Preparation of Paper Base Layer A-3] A paper base layer A-3 was obtained in the same manner as the paper base layer A-1, except that the amount of cationic starch added to the pulp slurry when preparing the paper stock was changed to 0.60 parts by mass.

[0123] [Preparation of Paper Base Layer A-4] Paper base layer A-4 was obtained in the same manner as paper base layer A-1, except that the amount of calcium carbonate added to the pulp slurry when preparing the paper stock was changed to 3.0 parts by mass, and the amount of cationic starch was changed to 0.00 parts by mass.

[0124] [Preparation of Paper Base Layer A-5] Paper base layer A-5 was obtained in the same manner as paper base layer A-1, except that the amount of calcium carbonate added to the pulp slurry when preparing the paper stock was changed to 10.0 parts by mass, and the amount of cationic starch was changed to 0.50 parts by mass.

[0125] [Preparation of Paper Base Layer A-6] Paper base layer A-6 was obtained in the same manner as paper base layer A-1, except that the amount of calcium carbonate added to the pulp slurry when preparing the paper stock was changed to 15.0 parts by mass, and the amount of cationic starch was changed to 0.70 parts by mass.

[0126] [Preparation of Paper Base Layer A-7] In preparing the pulp slurry, the amount of LBKP was 80 parts by mass, the amount of fine fibers was 15 parts by mass, A paper base layer A-7 was obtained in the same manner as the paper base layer A-6, except that the above-mentioned part was changed.

[0127] [Preparation of Paper Base Layer A-8] Paper base layer A-8 was obtained in the same manner as paper base layer A-6, except that in the preparation of the pulp slurry, the amount of LBKP was changed to 75 parts by mass and the amount of fine fibers was changed to 20 parts by mass.

[0128] [Preparation of Paper Base Layer A-9] The amount of paper material and press pressure during papermaking were adjusted to a basis weight of 400 g / m 2 A paper base layer A-9 was obtained in the same manner as the paper base layer A-2, except that the thickness was 469 μm.

[0129] [Preparation of Paper Base Layer A-10] Paper base layer A-10 was obtained in the same manner as paper base layer A-9, except that the amount of calcium carbonate added to the pulp slurry when preparing the paper stock was changed to 15.0 parts by mass, and the amount of cationic starch was changed to 0.70 parts by mass.

[0130] [Preparation of Paper Base Layer A-11] A paper base layer A-11 was obtained in the same manner as the paper base layer A-1, except that the cationic starch added to the pulp slurry during the preparation of the paper stock was not mixed.

[0131] [Preparation of Paper Base Layer A-12] A paper base layer A-12 was obtained in the same manner as the paper base layer A-1, except that the amount of cationic starch added to the pulp slurry when preparing the paper stock was changed to 0.80 parts by mass.

[0132] [Preparation of Paper Base Layer A-13] The amount of paper material and press pressure during papermaking were adjusted to a basis weight of 300 g / m 2 A paper base layer A-13 was obtained in the same manner as the paper base layer A-7, except that the thickness was 352 μm.

[0133] [Preparation of Paper Base Layer A-14] The amount of paper material and press pressure during papermaking were adjusted to a basis weight of 500 g / m 2 A paper base layer A-14 was obtained in the same manner as the paper base layer A-7, except that the thickness was 587 μm.

[0134] [Preparation of Paper Base Layer B-1] 50 parts by mass of hardwood bleached kraft pulp (LBKP) beaten into 520 mL of CSF and 50 parts by mass of softwood bleached kraft pulp (NBKP) beaten into 570 mL of CSF were mixed to obtain a pulp slurry. 0.75 parts by mass (solids content equivalent) of cationic starch ("Kate F" manufactured by Oji Cornstarch Co., Ltd.), 1.0 part by mass of rosin emulsion ("SPN-817" manufactured by Arakawa Chemical Industries Co., Ltd.), and 0.33 parts by mass of anion-modified polyacrylamide ("Polystron 1430" manufactured by Arakawa Chemical Industries Co., Ltd.) were added to 100 parts by mass (pulp solids content equivalent) of the obtained pulp slurry to prepare a paper stock. This sample was used to make paper on a twin-wire papermaking machine. The obtained paper was smoothed with a calendar to obtain a paper with a basis weight of 70 g / m. 2 Thus, a paper base layer B-1 having a thickness of 75 μm was obtained.

[0135] Example 1 One side of the paper base layer A-1 was coated with MDPE ("8010" manufactured by ENEOS NUC Corporation) by melt extrusion coating to a dry thickness of 20 μm, and the paper base layer B-1 was laminated to the coated surface to obtain a two-layered backing. After that, the outermost surface of the paper base layer A-1 was coated with a coating amount of 10 g / m2 after heat drying. 2 A coating liquid was applied in which 100 parts by mass of a water-based acrylic adhesive ("EM-575" manufactured by Arakawa Paint Co., Ltd.) was mixed with 3 parts by mass of a curing agent ("EM-550K" manufactured by Arakawa Paint Co., Ltd.) to form a backing with an adhesive layer. This backing with an adhesive layer and Film A (manufactured by Mitsubishi Chemical Corporation) with a three-layer structure of PE / PVOH / PP were mixed. A skin pack mount was prepared by dry laminating the adhesive layer and the PP layer together using a 40 μm thick polyester film ("Diamiron YF1966" by Epson Corporation) with the adhesive layer and the PP layer side by side.

[0136] <Examples 2 to 10 and Comparative Examples 1 to 4> A skin pack mount was prepared in the same manner as in Example 1, except that the paper base layer A was changed to that shown in Table 1.

[0137] The physical properties of the paper base layer and the skin pack mount were measured and evaluated by the following methods. The results are shown in Tables 1 and 2.

[0138] [Basic weight] The basis weights of the paper base layer and the skin pack liner were measured in accordance with JIS P 8124:2011 ("Paper and paperboard -- Determination of basis weight," revised on March 22, 2011). The measurement device used was the "Sartorius Cubis MSU524S" manufactured by Sartorius Japan Co., Ltd.

[0139] [Thickness] The thickness of the paper base layer and the skin pack backing paper were measured in accordance with JIS P 8118:2014 ("Paper and paperboard -- Test methods for thickness, density and specific volume", revised on November 20, 2014). The thickness of 10 samples was measured, and the arithmetic mean value was adopted as the thickness of the paper base layer. The measuring device used was a paper thickness gauge "No. 132 Digital Thickness Gauge" manufactured by Toyo Seiki Seisakusho Co., Ltd.

[0140] 〔density〕 The density of the paper base layer and the skin pack mount was calculated by dividing the basis weight measured by the above method by the thickness.

[0141] [Z-axis strength] The Z-axis strength of the skin pack backing paper was measured in accordance with JAPAN TAPPI No. 18-1:2007 ("Paper and paperboard -- Test method for internal bond strength -- Part 1: Z-axis tensile test method"). The measurement device used was a Tensilon universal material testing machine "RTC-1250A" manufactured by A&D Co., Ltd.

[0142] [Compressive strength] The compressive strength of the skin pack backing paper in the longitudinal and transverse directions was measured in accordance with JIS P 8156-2012 ("Paper and cardboard - Compressive strength test method - Short span method", established on April 20, 2012). The measurement device used was a short span compression tester "SE-052" manufactured by Lorentzen & Wettre.

[0143] [Taber stiffness] The Taber stiffness in the longitudinal and transverse directions of the skin pack backing paper was measured in accordance with JIS P 8125-2:2017 ("Paper and paperboard-Bending resistance test method-Part 2: Taber type testing machine method", enacted on March 21, 2017). The measuring device used was a "Digital Taber Stiffness Tester" manufactured by Toyo Seiki Seisakusho Co., Ltd.

[0144] [Ash content] The ash content of the skin pack mount was measured in accordance with JIS P 8251:2003. . The mount was incinerated using a muffle furnace "FO610" manufactured by Yamato Scientific Co., Ltd. The amount of ash was quantified using a "Sartorius Cubis MSU524S" manufactured by Sartorius Japan Co., Ltd.

[0145] [Amount of fine fibers] The paper base layer or the skin pack mount was cut into 40 cm squares, soaked in ion-exchanged water, adjusted to a solid content concentration of 2% by mass, and left to stand for 24 hours. After that, a standard disintegrator (manufactured by Kumagai Riki Kogyo Co., Ltd.) was used to disintegrate the pulp for 20 minutes to disintegrate the pulp into fibers. If undisintegrated pulp was present, disintegration was performed again for 20 minutes to disintegrate the pulp into fibers. The disintegration was performed in accordance with JIS P 8220-2:2012 ("Pulp - Disintegration methods - Part 1: Disintegration of chemical pulp", enacted on April 20, 2012). When measuring the amount of fine fibers in the pulp contained in the paper base material of the skin pack mount, the skin pack mount was subjected to a defibration process while still having the thermoplastic resin layer, and the slurry (dispersion of pulp fibers) was separated.

[0146] The slurry obtained by defibration was adjusted to a solid content of 0.1% by mass, and the pulp solid content was calculated in accordance with JIS P 8225:2003 ("Method of measuring solid content of pulp-paper material", established on May 20, 2003). The slurry was adjusted to a solid content of 0.004% by mass and 500 g, and the amount taken was recorded.

[0147] Using the obtained fiber sample, fibers with fiber lengths of 0.01 to 10.00 mm or less were photographed in a measurement cell with a depth of field of 0.5 mm in accordance with ISO 16065-2:2014 ("Pulp - Determination of fiber length by automated optical analysis - Part 2: Non-polarized method", published on January 15, 2007) using a fiber length measuring device (Valmet Ltd.'s "New Valmet FS5" laboratory pulp analyzer with UHD image analysis unit). Each fiber was detected and its fiber length was measured, and the content of fine fibers with a fiber length of 0.2 mm or less in the paper base layer was calculated from the results.

[0148] [Evaluation of folding of skin pack mount] The skin pack mount was punched to obtain rectangular pieces of paper measuring 280 mm in length and 180 mm in width. The punching process was carried out using an automatic flat-plate punching machine (Asahi Machinery Co., Ltd.'s "Carton Master AP-1300-TSG-8") at a rate of 6,000 sheets / hour.

[0149] As shown in FIG. 1A, a weight 13 weighing 200 g (oval shape with a long axis of 150 mm and a short axis of 100 mm) was attached to the center of a piece of paper 11 with cloth tape 15 so as to prevent it from coming off due to the impact of being dropped, thereby preparing an evaluation sample 10.

[0150] As shown in FIG. 1A, the evaluation sample 10 was placed at a height of 500 mm from the vinyl chloride floor 17 so that the short side would touch the ground when dropped. The evaluation sample 10 was then vertically dropped freely onto the vinyl chloride floor 17, and the presence or absence of creases was visually observed. This drop impact test was repeated, and the number of tests until the evaluation sample 10 was creased was counted. The above operation was performed for five evaluation samples, and the average number of tests until a crease was formed (rounded off to the first decimal place) was calculated and evaluated according to the following criteria. 4 to 2 were considered to be practical levels, and 1 was considered to be poor.

[0151] Evaluation criteria 4: 7.0 or more tests before a crease appears 3: The number of tests required before a crease appears is 5.0 to 6.0 2: The number of tests required to produce a crease is 3.0 to 4.0 times. 1: Fewer than 3.0 tests required before a crease appears

[0152] [Evaluation of curling of skin pack mounts] As shown in FIG. 1A, the evaluation sample 10, which is the same as the sample for evaluating the folding of the skin pack, was placed at a height of 500 mm from the vinyl chloride floor 17 so that the short side would touch the ground when dropped. Then, the evaluation sample 10 was allowed to fall vertically and freely onto the vinyl chloride floor 17. This drop impact test was performed seven times, and as shown in FIG. 1B, the end of the skin pack mount was cut out in three places (10 mm from both ends and the center), and the cross section of this cutout portion 19 was observed and analyzed using a laser microscope (Keyence Corporation's "VK-X3000 / 3100"). For each drop impact test, the extent to which the delamination had extended from the end was measured, the average value was calculated, and the following criteria were used for evaluation. 4 to 2 were considered to be practical levels, and 1 was considered to be poor.

[0153] Evaluation criteria 4: Delamination less than 1.00mm 3: Delamination is 1.00 mm or more but less than 1.25 mm 2: Delamination between 1.25mm and 1.50mm 1: Delamination is 1.50mm or more

[0154] [Evaluation of strength of skin pack mount] The skin pack mount was punched to obtain rectangular evaluation paper pieces measuring 280 mm in length and 180 mm in width. The punching was performed using an automatic flat-plate punching machine (Asahi Machinery Co., Ltd.'s "Carton Master AP-1300-TSG-8") at a speed of 6,000 sheets / hour.

[0155] As shown in FIG. 2A, the evaluation paper piece 21 was fixed on four square stands. Specifically, as shown in FIG. 2A, the evaluation paper piece 21 was placed on four square stands 23 so that the four corners of the evaluation paper piece 21 were placed on each stand by 1 cm×1 cm. Then, as shown in FIG. 2B and FIG. 2C, one weight 25 of 200 g (oval shape with major axis 150 mm×minor axis 100 mm) was placed on the center of the evaluation paper piece 21 to check the degree of bending. The number of centimeters that the evaluation paper piece 21 sunk was measured from both the vertical and horizontal directions, and the evaluation was made based on the larger bending according to the following criteria. 4 to 2 was a practical level, and 1 was a poor evaluation.

[0156] Evaluation criteria 4: Deflection is less than 1.00 cm 3: Deflection is 1.00 cm or more but less than 1.50 cm 2: Deflection is 1.50 cm or more but less than 2.50 cm 1: Deflection is 2.50 cm or more

[0157] [Table 1]

[0158] [Table 2] [Explanation of symbols]

[0159] 10 Evaluation sample 11 piece of paper 13 weight 15 Cloth Packing Tape 17 PVC flooring 19 Cut-out section 21 Evaluation Sheet 23 units 25 Weight

Claims

1. A skin pack mount having a thermoplastic resin layer on at least one surface of a paper substrate, The Z-axis strength of the skin pack mount is 280 kN / m ２ That's all. The skin pack mount has a compressive strength in the longitudinal direction of 23.0 kN / m or less, The Taber stiffness of the skin pack mount in the longitudinal direction is 95.0 mN m or less. Mounting paper for skin packs.

2. 2. The skin pack mount according to claim 1, wherein the ash content of the skin pack mount is 4.5% by mass or more.

3. 2. The skin pack mount according to claim 1, wherein the amount (number) of fine fibers having a fiber length of 0.2 mm or less in the pulp contained in the paper base material is 5.0 to 20.0%.

4. 2. The skin pack mount according to claim 1, wherein the thickness of the skin pack mount is 450 μm to 800 μm.

5. The skin pack mount has a basis weight of 650 g / m ２ 2. The skin pack mount according to claim 1, which is as follows:

6. The skin pack mount according to claim 1 , wherein the paper substrate comprises a paper substrate layer having a multi-layer structure.

7. A skin pack comprising the skin pack mount according to any one of claims 1 to 6, a storage item, and a resin film, A skin pack packaging body, in which the item to be contained is contained between the skin pack backing and the resin film.

Images