Skin pack mount and skin pack packaging body

Abstract

To provide a skin pack mount having cushioning properties capable of protecting a stored article, which is a packaging body to be packaged, from impact such as falling down, with excellent packaging suitability.SOLUTION: Provided is a skin pack mount with a thermoplastic resin layer on at least one surface of a paper base layer, the skin pack mount including, in the following order, the thermoplastic resin layer, a curl control layer, and the paper base layer. The curl control layer contains a pigment and has a coating weight of 4.0 g / m2 or more. The skin pack mount is curled such that the paper base layer is disposed on an inner side relative to the curl control layer. In a compression test on the skin pack mount, when a thickness dimension under a load of 0.49 hPa is T0 and a thickness dimension of a sample under a load of 49.03 hPa is Tm, the value of T0-Tm ranges from 0.10 to 3.00 mm.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] Skin pack packaging is often stored frozen to extend the edible period of food. In a low-temperature environment such as a freezer, the food itself hardens and the packaging material may become brittle. In addition, water droplets due to condensation or the like may adhere to the packaging, making it slippery and causing it to fall when picked up by a consumer. Regarding the strength of packaging materials in low-temperature environments, for example, Patent Document 1 discloses a film that is less likely to become brittle even under low-temperature conditions. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2022-145152 Summary of the Invention [Problem to be solved by the invention]

[0005] However, even if a film such as that disclosed in Patent Document 1 is used, the problem of damage to the contents due to an impact such as dropping the skin pack package still remains. Furthermore, the backing used in the skin pack packaging is also required to have packaging suitability. The present disclosure provides a skin pack liner that has cushioning properties that can protect the packaged item from impacts such as being dropped, and also has excellent packaging suitability. [Means for solving the problem]

[0006] The present disclosure is as follows. [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 curl control layer, and the paper base layer in this order; The curl-controlling layer contains a pigment and has a coating weight of 4.0 g / m 2 That's all, the skin pack mount is curled so that the paper base layer is on the inside with respect to the curl control layer, A sample cut from the center of the skin pack mount was measured using a KES compression property tester, and the compression area was 2.0 cm 2 When the thickness dimension of the sample under a load of 0.49 hPa is T0, and the sample is further compressed at a pressure rate of 0.02 mm / sec until it is under a load of 49.03 hPa, and the thickness dimension of the sample under a load of 49.03 hPa is Tm, A skin pack mount characterized in that the value of T0-Tm is 0.10 to 3.00 mm. [2] The skin pack mount according to [1], wherein the Runkel ratio of the pulp fibers constituting the paper base layer is 0.50 to 1.50. [3] The skin pack mount according to [1] or [2], wherein the ash content of the paper base layer is 10.0% by mass or less. [4] The skin pack mount according to any one of [1] to [3], wherein the glossiness of the skin pack mount measured from the paper base layer side is 5% or more. [5] The paper base layer is an interleaving paper including, from the curl control layer side, a paper base layer A, an adhesive layer, and a paper base layer B, The skin pack liner according to any one of [1] to [4], wherein when the basis weight of the paper base layer A is basis weight A and the basis weight of the paper base layer B is basis weight B, the ratio of the basis weight A to the basis weight B (basis weight A / basis weight B) is 3.0 to 7.0. [6] The skin pack mount according to any one of [1] to [5], wherein the curl amount of the skin pack mount equivalent to a length (MD) of 280 mm x width (CD) of 180 mm is 2 to 22 mm. [7] The skin pack mount according to any one of [1] to [6], wherein the thickness of the skin pack mount is 400 to 900 μm. [8] A skin pack packaging body having the skin pack mount according to any one of [1] to [7], a contained item, and a resin film, the skin pack mount has, in order from the side where the stored item is placed, the thermoplastic resin layer, the curl adjusting layer, and the paper base 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]

[0007] According to the present disclosure, it is possible to provide a skin pack liner that has cushioning properties that can protect the packaged item from impacts such as being dropped, and also has excellent packaging suitability. DETAILED DESCRIPTION OF THE INVENTION

[0008] 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.

[0009] 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).

[0010] <Skin pack mount> The present inventors have investigated ways to impart cushioning properties to a backing sheet that can protect the packaged items from impacts such as dropping, etc. They have found that by curling the skin pack backing sheet so that the paper base layer faces inward relative to the curl control layer, i.e., so that it is convex toward the packaged items, and by providing a compression amount within a specific range, not only cushioning properties but also packaging suitability can be improved.

[0011] The skin pack liner of the present disclosure has a thermoplastic resin layer on at least one side of a paper base layer. The skin pack liner has a thermoplastic resin layer, a curl control layer, and a paper base layer, in this order. For example, a contained item is placed on the thermoplastic resin layer side of the skin pack liner. The inventors have found that by satisfying all of the following requirements (A) to (C), a skin pack liner can be obtained that has cushioning properties that can protect the contained item, that is, the packaged object, from impacts such as being dropped, and also has excellent packaging suitability.

[0012] Requirement (A): The curl control layer contains a pigment, and the coating weight of the curl control layer is 4.0 g / m 2 That's all. Requirement (B): The skin pack mount is curled so that the paper base layer is on the inside relative to the curl control layer. Requirement (C): When a sample cut from the center of the skin pack mount is measured using a KES compression property tester, the compression area must be 2.0 cm 2When the thickness dimension of the sample under a load of 0.49 hPa is defined as T0, the sample is further compressed at a pressure rate of 0.02 mm / sec until it is under a load of 49.03 hPa, and the thickness dimension of the sample under a load of 49.03 hPa is defined as Tm, the value of T0-Tm is 0.10 to 3.00 mm.

[0013] Each requirement is explained below. Regarding requirement (A), the curl control layer is also a pigment coating layer containing pigment. When moisture is applied to one side of paper, the coated side curls inward. The curl control layer can prevent moisture from reaching the paper base from the thermoplastic resin layer side of the skin pack liner. Therefore, the effect of moisture on the skin pack liner is concentrated on the paper base layer side, allowing the paper base layer to expand and contract due to moisture to impart the appropriate curl.

[0014] The moisture here includes moisture from processes that can add moisture to paper, such as offset printing and flexographic printing. In offset printing, dampening water is applied to the paper, so if printing is done on only one side, the printed side will curl inward. On the other hand, if the paper has a pigment coating layer and the coating amount is sufficiently high, the dampening water will not reach the paper, preventing curling due to the dampening water.

[0015] Therefore, for example, a laminate having a pigment coating layer on one side of a paper base layer is used, and printing is performed from the pigment coating layer side where the contents will be placed. This allows for the production of a mount that is flat on the pigment coating layer side immediately after printing, and curls on the paper base layer side once printing on the opposite side of the paper base layer is completed.

[0016] Such curling can be achieved by incorporating a pigment into the curl-controlling layer and setting the coating weight of the curl-controlling layer at 4.0 g / m 2 This can be achieved by setting the coating weight to 4.0 g / m or more. 2 If the thickness is less than this, it is not possible to prevent moisture from reaching the paper substrate from the thermoplastic resin layer side, making it difficult to curl the skin pack mount and reducing the cushioning properties. In addition, such a curl-regulating layer is flat and not curled before moisture is added by printing or the like, and therefore has excellent printability.

[0017] The coating amount of the curl control layer is 5.0 to 30.0 g / m 2 is preferable, and 8.0 to 25.0 g / m 2 More preferably, 8.0 to 22.0 g / m 2 Within the above range, a more sufficient curl can be imparted to the skin pack mount.

[0018] Regarding requirement (B), the skin pack liner is curled so that the paper base layer faces inward relative to the curl control layer. In other words, the curl is formed so that it is convex toward the thermoplastic resin layer (convex toward the contained article). By having such a curl, the skin pack packaging can be easily folded down from the liner. If there is no curl or if the paper base layer curls outward (i.e., the curl is concave toward the thermoplastic resin layer), the skin pack package may not be able to provide sufficient cushioning when dropped horizontally with the backing facing downwards.

[0019] To impart such curl, a skin pack mount having a thermoplastic resin layer, a curl control layer, and a paper base layer in this order can be prepared, and the coating weight of the curl control layer can be set within the above-mentioned range. In addition to these layers, the skin pack mount may further include other layers, such as a pigment coating layer or a thermoplastic resin layer. For example, the skin pack mount may have a thermoplastic resin layer, a curl control layer, a paper base layer, and a pigment coating layer in this order. However, from the perspective of controlling curl, it is preferable that the coating weight of the curl control layer be greater than that of the pigment coating layer, and it is preferable that the coating weight of the pigment coating layer be less than the lower limit of the above-mentioned range. Thus, when there are multiple layers capable of controlling curl, such as pigment coating layers, in the present disclosure, the layer with the greatest coating weight is considered to be the curl control layer.

[0020] In order to induce curl after providing a curl control layer, for example, printing such as the offset printing can be used. Another method is to add moisture to the paper base layer. After laminating the curl control layer and the paper base layer, water is applied using various coaters (bar coater, blade coater, etc.) before cutting to induce curl. Furthermore, offset printing without ink causes dampening water to be applied to the paper base layer, which induces curl. Furthermore, curl can also be induced by spraying water on the back side using a spray bottle or the like after skin pack packaging.

[0021] Regarding requirement (C), when a sample cut out from the center of the skin pack mount is measured using a KES compression property tester, the compression area is 2.0 cm 2 The thickness of the sample under a load of 0.49 hPa is defined as T0. Next, the sample is further compressed at a rate of 0.02 mm / sec until it is under a load of 49.03 hPa, and the thickness of the sample under a load of 49.03 hPa is defined as Tm. At this time, the value of T0 - Tm is 0.10 to 3.00 mm.

[0022] The load for the T0 measurement was 75g and had a base area of ​​150cm 2 This corresponds to the force applied when a (15cm x 10cm) object is placed on the backing. This is the load assumed when the stored item is placed on the backing. The sample is compressed from this load until it reaches a load of 49.03 hPa, and Tm is measured. Therefore, the value of T0 - Tm represents the cushioning performance of the skin pack backing itself, including cushioning due to curl.

[0023] When the T0-Tm value is 0.10 to 3.00 mm, sufficient cushioning properties can be obtained while also achieving packaging suitability. When the T0-Tm value is less than 0.10 mm, cushioning properties cannot be obtained. When the T0-Tm value exceeds 3.00 mm, curling becomes too strong. When curling becomes too strong, misalignment of the contents or poor film adhesion due to misalignment of the backing sheet during transport is likely to occur, impairing packaging suitability.

[0024] The value of T0-Tm is preferably 0.12 to 2.60 mm, more preferably 0.50 to 2.60 mm, even more preferably 1.00 to 2.00 mm, and even more preferably 1.40 to 1.90 mm. The T0-Tm value can be controlled by the basis weight, thickness, amount of curl, Taber stiffness, etc. of the paper base layer. Increasing the thickness of the paper base layer and decreasing the density tends to increase the T0-Tm value. Increasing the amount of curl also tends to increase the T0-Tm value. Increasing the Taber stiffness reduces the amount of curl that occurs when contents are placed on the paper, so the T0-Tm value tends to increase.

[0025] The value of T0 is preferably 0.70 to 3.50 mm, more preferably 1.00 to 3.30 mm, and even more preferably 2.00 to 2.55 mm. The value of Tm is preferably 0.30 to 1.00 mm, and more preferably 0.50 to 0.80 mm.

[0026] The Taber stiffness of the skin pack mount is preferably 25 mN·m or more to provide strength to the mount. Specifically, the Taber stiffness in the lateral direction of the skin pack mount 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.

[0027] Furthermore, the Taber stiffness of a skin pack mount in the longitudinal direction is usually greater than the Taber stiffness in the transverse direction. Therefore, the range of the Taber stiffness of the skin pack mount in the longitudinal direction is not particularly limited, but 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. 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 methods - Part 2: Taber type testing machine method", established on March 21, 2017).

[0028] The Runkel ratio of the pulp fibers that make up the paper base layer is preferably 0.50 to 1.50, and more preferably 0.55 to 1.45. The Runkel ratio is calculated by dividing twice the fiber wall thickness by the lumen diameter. If the Runkel ratio is small, the fibers are more likely to be crushed during papermaking, the moisture expansion rate increases, and shrinkage upon drying increases, resulting in a larger amount of curl. If the Runkel ratio is within the above range, the amount of curl increases, further improving cushioning properties. The Runkel ratio can be controlled, for example, by selecting the pulp.

[0029] In the present disclosure, the paper base layer may be a single sheet of paper, but may also be, for example, a laminated paper having a paper base layer A, an adhesive layer, and a paper base layer B. When the paper base layer is a laminated paper, the effect of moisture on the paper base layer A is limited, so the Runkel ratio of the paper base layer B is measured from the perspective of the cushioning effect due to curl. In other words, the Runkel ratio of the pulp fibers that make up the paper base layer is the Runkel ratio of the paper base layer that is located farthest from the curl control layer.

[0030] The ash content in the paper base layer is preferably 10.0% by mass or less. The ash content in the paper base layer is more preferably 1.0 to 10.0% by mass, even more preferably 3.0 to 10.0% by mass, and even more preferably 5.0 to 9.0% by mass. When the ash content is 10.0% by mass or less, the fiber content in the paper base layer increases, which increases the moisture expansion rate and the amount of curl. This further improves cushioning properties. The ash content can be controlled by the amount of material that can become ash, such as calcium carbonate, added. If the paper base layer is an interleaf paper, the ash content is also measured in the paper base layer B from the perspective of the cushioning effect against curling. In other words, the ash content of the paper base layer is the ash content of the paper base layer located farthest from the curl control layer.

[0031] The glossiness measured from the paper substrate layer side of the skin pack mount is preferably 5% or more. The glossiness is preferably 5 to 30%, more preferably 8 to 25%, even more preferably 10 to 25%, and even more preferably 15 to 25%. A glossiness of 5% or more makes it easier to suppress printing unevenness and improves printing workability. The glossiness can be controlled by coating or the drying process during papermaking. For example, it can be easily increased by using a Yankee dryer. Drying using a Yankee dryer causes residual strain in the paper, which reduces curling. The amount can be increased.

[0032] The paper base layer may be a single-layer paper base layer, or may be a slip sheet having multiple paper base layers and 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 layer is preferably a slip sheet consisting of, from the curl control layer side, a paper base layer A, an adhesive layer, and a paper base layer B. When the basis weight of the paper base layer A is basis weight A and the basis weight of the 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 3.0 to 7.0, more preferably 3.2 to 6.5. By using a slip sheet, the paper base layer on the curl control layer side is less susceptible to the effects of moisture, making it easier to control the amount of curl.

[0033] By keeping the grammage A / grammage B ratio at 7.0 or less, the proportion of paper base layer B, which is more likely to contribute to curling, increases, which tends to increase the amount of curl and improves cushioning.By keeping the grammage A / grammage B ratio at 3.0 or more, more sufficient packaging suitability is obtained.

[0034] The curl amount of the skin pack mount equivalent to 280 mm in length (MD) × 180 mm in width (CD) is preferably 2 to 22 mm, more preferably 5 to 20 mm, even more preferably 10 to 18 mm, and even more preferably 12 to 15 mm. By keeping it within the above range, better cushioning properties can be achieved while also improving packaging suitability.

[0035] The curl amount here is the average value of the lifting at the four corners when a sample cut out from the skin pack mount to a length (MD) of 280 mm and a width (CD) of 180 mm is placed flat on a horizontal hard surface with the curl control layer side facing down relative to the paper base material (i.e., the paper base layer side facing up).The numerical value is a positive value, and if lifting is observed at the four corners, it can be said that the paper base layer is curling inward. On the other hand, if no lifting occurs, the paper is placed flat in the same manner with the paper base layer side facing downwards, and the average lifting at the four corners is measured, but the curl amount value in this case will be a negative value.

[0036] As mentioned above, the amount of curl can be controlled by the coating weight of the curl control layer, the Runkel ratio, the ash content, etc. In addition, by using a slip sheet consisting of a paper base layer A, an adhesive layer, and a paper base layer B as the paper base layer and adjusting the basis weight ratio of paper base layer A and paper base layer B, the amount of curl after printing can be adjusted. Furthermore, by using a Yankee dryer during papermaking of the paper base layer, it is possible to increase the amount of curl due to residual strain, and by creating a glossy surface on one side, printing workability can also be improved.

[0037] The basis weight of the skin pack mount is not particularly limited, but is preferably 400 to 1000 g / m 2 , more preferably 450 to 800 g / m 2 , and more preferably 500 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.

[0038] The thickness of the skin pack mount is not particularly limited, but is preferably 400 to 900 μm, more preferably 500 to 800 μm, and even more preferably 600 to 700 μm. In addition to the T0-Tm being in the above-mentioned range, a thickness in the above range provides even better cushioning properties. The density of the skin pack mount is not particularly limited, but is preferably 0.60 to 1.10 g / cm 3and 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.

[0039] (Paper base layer) The skin pack mount is not particularly limited in terms of the constituent material and layer structure of the paper base layer, as long as it satisfies the above curl and T0-Tm. The paper base layer may be a slip sheet containing two or more paper base layers, or may be a single sheet consisting of one paper base layer. From the viewpoint of curling, it is preferable that the paper base layer be a slip sheet.

[0040] When the paper substrate layer is a slip sheet, there are no particular limitations on 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. The paper substrate layers preferably have a paper substrate layer A, an adhesive layer, and a paper substrate layer B in this order. A slip sheet having a paper substrate layer A, an adhesive layer, and a paper substrate layer B in this order may be a slip sheet consisting of only the paper substrate layer A, the adhesive layer, and the paper substrate layer B, or may be a slip sheet in which another paper layer is laminated via an adhesive layer. In this case, the paper substrate layer B may be the same paper layer as the paper substrate layer A. Furthermore, the other paper layer may be the same paper layer as the paper substrate layer A or the paper substrate layer B.

[0041] When the paper base layer is an interleaf paper, the side of the paper base layer that contacts the curl control layer is referred to as paper base layer A, but pigment coating layers that can serve as curl control layers may be provided on both sides of the paper base layer. In that case, as described above, the pigment coating layer with the largest coating weight is referred to as the curl control layer. For example, in the case of a skin pack mount, there may be an embodiment in which there is no pigment coating layer on the side of the paper base layer opposite the side facing the curl control layer, or there is an embodiment in which there is a pigment coating layer with a coating amount smaller than the coating amount of the curl control layer on the side of the paper base layer opposite the side facing the curl control layer. The coating amount of the pigment coating layer on the side of the paper base layer opposite to the curl control layer is preferably 0 g / m 2 More than 4.0g / m 2More preferably, it is 0 to 2.5 g / m 2 and more preferably 0 to 2.0 g / m 2 is.

[0042] The overall basis weight of the paper base layer included in the skin pack mount is preferably 200 to 1000 g / m 2 , more preferably 300 to 700 g / m 2 , and more preferably 400 to 600 g / m 2 , particularly preferably 450 to 600 g / m 2 is.

[0043] The basis weights of the paper base layers A and B preferably satisfy the above-mentioned ratio (basis weight A / basis weight B), but are not particularly limited. 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 , particularly preferably 350 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 200 g / m 2 , and more preferably 50 to 150 g / m 2 , particularly preferably 60 to 130 g / m 2 is.

[0044] 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.

[0045] 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.

[0046] 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, and from the standpoint 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 standpoint of printing workability 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.

[0047] 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 printing workability, bleached kraft pulp (BKP) is preferred.

[0048] 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 of hardwood kraft pulp (LKP) to softwood kraft pulp (NKP) (LKP / NKP) is not particularly limited as long as it is a ratio used in general paper, and is preferably 1 / 99 to 99 / 1, more preferably 30 / 70 to 70 / 30.

[0049] When the paper base layer is an interleaving paper, for example, when paper base layer A and paper base layer B are used, the mass ratio (LKP / NKP) can be calculated for each paper base material. The calculation of the mass ratio (LKP / NKP) does not include ultrafine fibers, which will be described later.

[0050] The paper base layer may be made of either hardwood kraft pulp (LKP) or softwood kraft pulp (NKP). For example, the pulp may be selected depending on the Runkel ratio in order to impart a desired curl.

[0051] For example, the average fiber width of the pulp excluding microfibers, which will be described later, 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 excluding microfibers, which will be described later, is preferably 0.40 to 2.50 mm, and more preferably 0.50 to 2.40 mm.

[0052] 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 device also uses an attached camera to detect and measure individual fibers, capturing images in a measurement cell with a depth of field of 0.5 mm in accordance with the ISO 16505-2:2014 standard. The device captures fiber lengths between 0.01 mm and 10.00 mm. For the measurement of "fiber length" and "fiber width," fibers between 0.2 mm and 7.0 mm in length shall be selected. The average fiber width shall be the arithmetic mean value of the fiber widths of all the fibers obtained.

[0053] The pulp may contain ultrafine fibers. By including ultrafine fibers in the pulp, the gaps between the fibers can be filled, improving the density. As a result, it becomes easier to maintain the Taber stiffness required for the backing paper. In this specification, "ultra-fine fibers" refers to fibers with a fiber length of 0.2 mm or less. The fiber length of pulp is measured using a fiber length measuring device (Valmet FS-5 with UHD base unit, manufactured by Valmet Co., Ltd.) in accordance with ISO 16065-2:2014.

[0054] The amount of ultrafine fibers in the pulp is preferably 1 to 20% by mass, more preferably 5 to 15% by mass. When a specific amount of ultrafine fibers is to be contained in the pulp, ultrafine fibers obtained by pulping hardwood kraft pulp such as bleached hardwood kraft pulp using a known pulping device such as a cutter mill may be added during the preparation of the pulp.

[0055] 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 printability, the 75° gloss of the paper base layer is preferably 5% or more, more preferably 10% or more and 70% or less.

[0056] (adhesive layer) When the paper base material is a slip sheet, the adhesive layer that bonds the paper base layer A and the 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 of the paper base layers with a heat-melted adhesive layer and then laminating the other paper base layer.

[0057] 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.

[0058] The adhesive layer may be formed using the following adhesives. 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 selected from the group consisting of an acrylic adhesive, a polyurethane adhesive, and an isocyanate adhesive. It is preferable to use one or more of these adhesives, and more preferable to use an acrylic adhesive because the adhesive strength can be easily controlled and it has excellent heat resistance.

[0059] 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.

[0060] 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.

[0061] (Curl adjustment layer) The skin pack mount has a curl-control layer containing a pigment. The pigment is not particularly limited, and examples thereof include inorganic pigments such as heavy calcium carbonate, light calcium carbonate, titanium dioxide, calcium sulfite, gypsum, barium sulfate, talc, kaolin, clay, calcined kaolin, white carbon, amorphous silica, delaminated kaolin, diatomaceous earth, magnesium carbonate, aluminum hydroxide, calcium hydroxide, magnesium hydroxide, zinc hydroxide, zinc oxide, magnesium oxide, bentonite, sericite, papermaking sludge, and recycled particles made from deinking floss, as well as organic pigments such as urea-formalin resin microparticles and hollow microparticles. These can be used alone or in combination of two or more.

[0062] The pigment is preferably at least one selected from the group consisting of heavy calcium carbonate, titanium dioxide, and kaolin.The average particle size of the pigment is preferably 0.2 to 2.0 μm, more preferably 0.3 to 1.5 μm.

[0063] Among these, it is preferable to use heavy calcium carbonate having an average particle size of 0.50 to 1.50 μm for the curl-control layer, and more preferably 0.80 to 1.20 μm. The heavy calcium carbonate preferably accounts for 50% by mass or more of all pigments contained in the curl-controlling layer, more preferably 55 to 75% by mass, and even more preferably 60 to 70% by mass.

[0064] The curl control layer preferably further contains kaolin as a pigment having an average particle size of 1.2 μm or less. The average particle size is preferably 0.2 to 0.8 μm. The average particle size is measured by a light scattering method and is the particle size at which the cumulative mass is 50%. The content of the pigment in the curl adjusting layer is preferably 50 to 99% by mass, and more preferably 75 to 95% by mass.

[0065] When the curl adjustment layer contains titanium oxide, the curl adjustment layer can also serve as the laser printable layer described below. When the curl adjustment layer contains titanium oxide and also serves as the laser printable layer, the content of titanium oxide in the curl adjustment layer is the same as the content of titanium oxide in the laser printable layer described below, and the preferred embodiments are also the same.

[0066] The curl control layer may contain a binder resin. The binder resin is not particularly limited, but it is preferable to use a copolymer latex. The glass transition temperature of the copolymer latex is preferably within the range of -40 to 5°C. The glass transition temperature is more preferably -40 to -30°C. The average particle size of the copolymer latex in the curl control layer is about 70 to 300 nm. The range is preferably 110 to 200 nm.

[0067] The copolymer latex in the curl control layer is not particularly limited, and examples thereof include conjugated diene polymer latexes such as styrene-butadiene copolymers and methyl methacrylate-butadiene copolymers; acrylic acid polymer latexes such as acrylic acid ester and / or methacrylic acid ester polymers or copolymers; vinyl polymer latexes such as ethylene-vinyl acetate copolymers; and alkali-soluble or alkali-insoluble polymer latexes obtained by modifying these polymer latexes with a functional group-containing monomer such as a carboxyl group. One or more of these may be selected and used. It is preferable to use a styrene-butadiene copolymer latex.

[0068] The content of the polymer latex in the curl control layer is not particularly limited, but is preferably 5 to 25 parts by mass, more preferably 7 to 15 parts by mass, in solids content, per 100 parts by mass of the pigment contained in the curl control layer. When the content is within this range, good coating layer strength can be obtained.

[0069] The curl control layer may further contain a binder resin other than latex. Examples of the binder resin other than latex include water-soluble binder resins such as at least one selected from the group consisting of polyvinyl alcohol, oxidized starch, cationized starch, esterified starch, and starches such as dextrin. The content of the water-soluble binder resin is preferably 1 to 5 parts by mass per 100 parts by mass of the pigment.

[0070] The curl control layer may contain a dispersant such as sodium polyacrylate and other additives as appropriate. The coating means for the curl-regulating layer is not particularly limited, and a known coating device such as a rod coater may be used. The solvent may be water, ethyl acetate, or the like.

[0071] As mentioned above, pigment coating layers may be provided on both sides of the paper substrate layer, and in this case, the pigment coating layers may contain the same materials as those mentioned above for the curl control layer.

[0072] (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.

[0073] 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.

[0074] 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.

[0075] 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. As the polyamide resin, aromatic polyamides are preferred. Polyamide MXD6 is more preferred. 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.

[0076] 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.

[0077] 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. Specific examples include polyester resins such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polylactic acid, and polybutylene succinate; polyolefin resins such as polyvinyl chloride, polyvinylidene chloride, polybutene, polybutadiene, ethylene-vinyl acetate copolymer, polyethylene, polypropylene, ethylene-vinyl alcohol copolymer, ethylene-propylene copolymer, and polymethylpentene; polycarbonate; polyurethane; polyamides such as nylon 6; polyacrylonitrile; and poly(meth)acrylate.

[0078] 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 extrusion lamination properties 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 extrusion lamination properties.

[0079] 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.

[0080] 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, an unstretched multilayer film made of a nylon-ethylene-vinyl alcohol copolymer (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.

[0081] (Adhesive layer) If the surface of the thermoplastic resin layer has adhesive properties, the thermoplastic resin layer may be directly adhered to the surface of the curl control layer, but it is preferable to have an adhesive layer between the curl control 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.

[0082] 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 curl-regulating 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 adhesive, and it is more preferable to use a mixed coating liquid in which a curing agent is mixed with a coating liquid containing the adhesive.

[0083] 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.

[0084] (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 be present between the thermoplastic resin layer, the curl control layer, and the paper substrate layer. It may also include a laser printable layer that can be printed by ultraviolet laser printing.

[0085] (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.

[0086] The laser printing layer can be provided on the surface of the thermoplastic resin layer opposite to the surface in contact with the paper substrate, between the thermoplastic resin layer and the paper substrate, on the pigment coating layer, etc. Alternatively, the curl control layer, pigment coating layer, or paper substrate may contain titanium oxide, so that the curl control layer, pigment coating layer, or paper substrate also serves as a laser printing layer.

[0087] 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.

[0088] 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.

[0089] 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.

[0090] Furthermore, when a laser printing layer is provided between the thermoplastic resin layer and the paper substrate, the thermoplastic resin layer functions as a protective 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 this tends to result in a printed image with high print density and excellent print clarity for each point, which is even more effective.

[0091] In addition, for example, the skin pack mount has a side of the curl adjusting layer facing the thermoplastic resin layer. A printed layer may be provided on at least one of the surfaces of the paper substrate layer facing the curl control layer and the surface opposite the curl control layer, and it is preferable to have a printed layer on both surfaces (i.e., both surfaces of the skin pack mount). The printed layer is preferably a printed layer made of ink printed by offset printing. As described above, the presence of the curl control layer can impart good curl with moisture from printing. 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.

[0092] <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.

[0093] (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.

[0094] Next, the pulp-containing paper stock is made into a paper base layer. The obtained paper base layer can be used as a single sheet to form a paper base. If necessary, the obtained paper base layers can also be bonded together with an adhesive layer to form a paper base.

[0095] 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.

[0096] 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 50 to 60°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.

[0097] Preferably, calcium carbonate is added to the pulp. The amount of calcium carbonate is preferably 3 to 20 parts by mass, more preferably 5 to 12 parts by mass, per 100 parts by mass of pulp. The ash content can be controlled by the amount of calcium carbonate. 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. 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.

[0098] 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. When making paper, it is preferable to use a paper machine equipped with a Yankee dryer.

[0099] In addition, the obtained paper base layer is subjected to a surface treatment using a calendar to adjust the thickness and profile. For the calendering, a known calendering machine can be appropriately selected and used.

[0100] When the paper base layer is a single sheet, a curl control layer may be provided on the obtained paper base layer. When the paper base layer is a laminated paper, the procedure for forming the curl control layer after obtaining the paper base layer A and the paper base layer B is not particularly limited. The paper base layer A and the paper base layer B may be bonded together via an adhesive layer to obtain a laminated paper base layer, and then the curl control layer may be provided. Alternatively, a curl control layer may be provided on the paper base layer A, and an adhesive layer and the paper base layer B may be provided on the side of the paper base layer A opposite to the side in contact with the curl control layer.

[0101] It is preferable to first provide a curl control layer on paper base layer A, and then perform the lamination step of paper base layer B. For example, the surface of paper base layer A or B can be coated with the resin contained in the heat-melted adhesive layer described above, and the other paper base layer can be laminated onto the coated surface to obtain a laminated paper base layer.

[0102] 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 laminating another paper substrate layer to the coated surface. In this case, the adhesive coating solution 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 infrared radiation. 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.

[0103] (Formation of curl adjustment layer) The method for manufacturing a skin pack mount includes a step of obtaining a laminate in which a curl control layer is formed on a paper base layer. The curl control layer can be formed, for example, by preparing a curl control layer coating liquid containing a pigment and, if necessary, an adhesive and additives such as calcium carbonate, applying the coating liquid by a known method, and then appropriately drying the liquid. The amount of coating liquid applied should be such that the above-mentioned coating amount is achieved. As described above, the curl control layer may be formed after obtaining the slip sheet, or the curl control layer may be formed on paper base layer A and then paper base layer B may be laminated to obtain a laminate in which the curl control layer is formed on the paper base layer.

[0104] (Printing process) A laminate having a curl control layer formed on a paper substrate layer may be printed as needed. Preferably, printing is performed on the curl control layer side, and then printing is performed on the opposite side of the paper substrate layer from the curl control layer side. By printing in this order, the paper substrate layer is less likely to curl when printing on the curl control layer side, which improves the workability of the next printing on the opposite side.

[0105] (Formation of thermoplastic resin layer) Next, a step of providing a thermoplastic resin layer on the laminate is carried out. A skin pack mount can be obtained by providing a thermoplastic resin layer on at least the curl control layer side of the laminate. When a thermoplastic resin layer is provided on one or both surfaces of the paper substrate layer, the thermoplastic resin layer may be directly adhered to the paper substrate layer, or may be adhered to the paper substrate layer via an adhesive layer. In the latter case, it is preferable to apply a coating liquid containing an adhesive to the surface of the paper substrate layer, and then laminate the thermoplastic resin layer on the surface of the paper substrate layer via the adhesive layer. In this case, a film may be attached to the paper substrate as the thermoplastic resin layer.

[0106] (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.

[0107] <Skin pack packaging> The present disclosure relates to a skin pack packaging body having the 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 curl control layer, and a paper base 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.

[0108] 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.

[0109] 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]

[0110] 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.

[0111] 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. A nonionic surfactant (Noigen LF-100X (polyoxyethylene alkyl ether) manufactured by Daiichi Kogyo Seiyaku Co., Ltd., HLB: 14.5) was dispersed in the obtained cooking white liquor at a concentration of 2.1% based on the bone dry mass of the wood chips, and the resulting mixture was added to the wood chips in an autoclave, followed by kraft cooking at a cooking temperature of 165°C for 2 hours.

[0112] 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.

[0113] 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.

[0114] [Table 1]

[0115] Paper base layer A and laminate A were obtained by the following procedure. (Preparation of Paper Base Layer A-1 and Laminate A-1) 85 parts by mass of beaten hardwood bleached kraft pulp 1 (LBKP1) was mixed with 450 mL of CSF, 5 parts by mass of beaten softwood bleached kraft pulp 1 (NBKP1) was mixed with 500 mL of CSF, and 10 parts by mass of ultrafine fibers to obtain a pulp slurry. The ultrafine fibers were prepared by mechanically crushing dry LBKP sheets using a cutter mill (HORAI Corporation's "HA8 2542 30E", screen 0.24 mm) and then separating pulp fibers with a length of 0.2 mm or less using a fiber classifier (Aikawa Iron Works Co., Ltd.'s "MAX-F700"). To 100 parts by mass of the obtained pulp slurry, 0.80 parts by mass (solid content equivalent) of aluminum sulfate (manufactured by Asahi Chemical Industry Co., Ltd.), 10 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 stock for the surface layer, the undersurface layer, the middle layer, the under-back layer, and the back layer. Using this stock, paper was made on a five-layer short wire paper machine with the same set basis weight for all five layers. When the layers were overlapped, 2 g / m of cationic starch was added between each layer. 2 The basis weight was 515 g / m 2 The press pressure was adjusted so that the paper thickness was 609 μm, and a paper base layer A was obtained.

[0116] (Preparation of Coating Liquid for Curl Adjusting Layer) A pigment dispersion with a solids concentration of 68% by mass was prepared using 30 parts of kaolin (Thiele Kaolin "Kaofine", average particle size 0.5 μm), 65 parts of heavy calcium carbonate (Fimatec Corporation "FMT90", average particle size 1.06 μm), and 5 parts of titanium dioxide (Cosmo Chemical Co., Ltd. "KA-100") as pigments, with 0.1% sodium polyacrylate added per 100 parts of pigment as a dispersant, using a Coles disperser. The solvent for the dispersion was water. Next, 2 parts of oxidized starch ("Ace Y" manufactured by Oji Cornstarch Co., Ltd.) and styrene-butadiene copolymer latex I ("T2548A" manufactured by JSR Corporation, glass transition temperature -34°C, average viscosity 10 ... 10 parts of the pigment having a particle diameter of 140 nm was added to obtain a coating liquid for the curl adjusting layer having a final solid content of 60% by mass.

[0117] (Preparation of laminate) The coating amount of the curl control layer was 5.0 g / m2 on one side of the paper base layer A using a rod coater. 2The curl control layer was formed by coating and drying the coated film so that the curl control layer was -3 mm. The dryer conditions were adjusted so that the final curl amount was -3 mm. The paper base layer A on which the curl control layer was formed was subjected to a paper feed process using a two-nip soft calender with a metal roll surface temperature of 200°C, to obtain a laminate A-1 in which a curl control layer was formed on the paper base layer A-1.

[0118] (Paper base layer A-2, laminate A-2) The paper base layer has a basis weight of 510 g / m 2 The paper thickness was set to 604 μm, and the coating weight of the curl control layer was set to 10.0 g / m 2 A paper base layer A-2 and a laminate A-2 were produced in the same manner as in A-1, except that:

[0119] (Paper base layer A-3, laminate A-3) The paper base layer has a basis weight of 500 g / m 2 The paper thickness was 593 μm, and the coating weight of the curl control layer was 20.0 g / m 2 A paper base layer A-3 and a laminate A-3 were produced in the same manner as in A-1, except that the above was used.

[0120] (Paper base layer A-4, laminate A-4) Paper base layer A-4 and laminate A-4 were prepared in the same manner as A-2, except that in the pulp preparation process, the amount of LBKP2 beaten to 450 mL of CSF was changed to 5 parts by mass and the amount of NBKP2 beaten to 500 mL of CSF was changed to 95 parts by mass.

[0121] (Paper base layer A-5, laminate A-5) A paper base layer A-5 and a laminate A-5 were produced in the same manner as A-2, except that the amount of calcium carbonate added in the pulp preparation step was changed to 5 parts by mass.

[0122] (Paper base layer A-6, laminate A-6) The paper base layer has a basis weight of 508 g / m 2 The press pressure was adjusted so that the paper thickness would be 599 μm. In the coating process, single-sided coating was changed to double-sided coating, and the coating amount on one side was 10.0 g / m2. 2 (Curl control layer), coating amount on the opposite side: 2.0 g / m2 (Pigment coating layer). Furthermore, in the drying process after coating, the dryer conditions were adjusted so that curl was -3 mm. Other conditions were the same as for A-1, and a paper base layer A-6 and a laminate A-6 were produced.

[0123] (Paper base layer A-7, laminate A-7) A paper base layer A-7 and a laminate A-7 were produced in the same manner as A-2, except that in the papermaking process, a long-rod paper machine equipped with a Yankee dryer was used for papermaking.

[0124] (Paper base layer A-8, laminate A-8) The paper base layer has a basis weight of 440 g / m 2 A paper base layer A-8 and a laminate A-8 were prepared in the same manner as in A-2, except that the paper thickness was changed to 509 μm.

[0125] (Paper base layer A-9, laminate A-9) The paper base layer has a basis weight of 410 g / m 2 A paper base layer A-9 and a laminate A-9 were prepared in the same manner as in A-2, except that the paper thickness was changed to 487 μm.

[0126] (Paper base layer A-10, laminate A-10) The paper base layer has a basis weight of 390 g / m 2 The paper thickness is 464 μm, but it is the same as A-2. A paper base layer A-10 and a laminate A-10 were prepared by this method.

[0127] (Paper base layer A-11, laminate A-11) The paper base layer has a basis weight of 500 g / m 2 The press pressure was adjusted so that the paper thickness would be 593 μm. In the coating process for the curl control layer, single-sided coating was changed to double-sided coating, and the coating amount on both sides was 10.0 g / m. 2 Furthermore, in the drying process after coating, the dryer conditions were adjusted so that curling was -3 mm. Other conditions were the same as for A-1, and a paper base layer A-11 and a laminate A-11 were produced.

[0128] (Paper base layer A-12, laminate A-12) The paper base layer has a basis weight of 518 g / m 2 The paper thickness was set to 612 μm, and the coating weight of the curl control layer was set to 2.0 g / m 2 A paper substrate layer A-12 and a laminate A-12 were produced in the same manner as in A-1, except that the above was used.

[0129] (Paper base layer A-13, laminate A-13) The paper base layer has a basis weight of 520 g / m 2 A paper base layer A-13 and a laminate A-13 were prepared in the same manner as A-1, except that the paper thickness was changed to 614 μm and no curl control layer was applied.

[0130] (Paper base layer A-14, laminate A-14) The paper base layer has a basis weight of 460 g / m 2 A paper base layer A-14 and a laminate A-14 were prepared in the same manner as in A-2, except that the paper thickness was changed to 541 μm.

[0131] (Paper base layer A-15, laminate A-15) The paper base layer has a basis weight of 250 g / m 2 A paper base layer A-15 and a laminate A-15 were prepared in the same manner as in A-2, except that the paper thickness was changed to 315 μm.

[0132] (Paper base layer A-16, laminate A-16) The paper base layer has a basis weight of 260 g / m 2 A paper base layer A-16 and a laminate A-16 were prepared in the same manner as in A-2, except that the paper thickness was changed to 326 μm.

[0133] The paper base layer B was prepared in the following manner. (Preparation of Paper Base Layer B-1) Pulp slurry was obtained by mixing and beating 50 parts by mass of beaten hardwood bleached kraft pulp 1 (LBKP1), 20 parts by mass of LBKP2, and 30 parts by mass of beaten softwood bleached kraft pulp 1 (NBKP1) in 520 mL of CSF. To 100 parts by mass of the resulting pulp slurry, 0.75 parts by mass (solids equivalent) of cationic starch ("Kate F" manufactured by Oji Cornstarch Co., Ltd.), 1.0 part by mass of rosin emulsion ("SPN" manufactured by Arakawa Chemical Industries, Ltd.), and 0.33 parts by mass of anion-modified polyacrylamide ("Polystron" manufactured by Arakawa Chemical Industries, Ltd.) were added, and paper was made using a Fourdrinier paper machine equipped with 6 parts by mass of calcium carbonate and a multi-cylinder dryer. The basis weight was 70 g / m. 2 The paper was then smoothed with a calendar to a thickness of 75 μm, to obtain a paper base layer B-1.

[0134] (Preparation of paper base layer B-2) Basis weight: 100g / m 2 Next, a paper base layer B-2 was prepared in the same manner as B-1, except that the paper thickness was 107 μm.

[0135] (Preparation of paper base layer B-3) Basis weight: 120g / m 2 Next, a paper base layer B-3 was prepared in the same manner as B-1, except that the paper thickness was 130 μm.

[0136] (Preparation of paper base layer B-4) Paper base layer B-4 was prepared in the same manner as B-3, except that in the pulp preparation process, the amount of LBKP2 beaten to 450 mL of CSF was changed to 5 parts by mass and the amount of NBKP2 beaten to 500 mL of CSF was changed to 95 parts by mass.

[0137] (Preparation of paper base layer B-5) Paper base layer B-5 was prepared in the same manner as B-3, except that in the pulp preparation process, 5 parts by mass of LBKP1 beaten to 450 mL of CSF and 95 parts by mass of NBKP1 beaten to 500 mL of CSF were used.

[0138] (Preparation of paper base layer B-6) A paper base layer B-6 was produced in the same manner as B-4, except that in the pulp preparation step, the amount of calcium carbonate added was changed to 5 parts by mass.

[0139] (Preparation of paper base layer B-7) A paper base layer B-7 was prepared in the same manner as B-4, except that in the pulp preparation step, the amount of calcium carbonate added was changed to 7 parts by mass.

[0140] (Preparation of paper base layer B-8) Paper base layer B-8 was produced in the same manner as B-1, except that in the pulp preparation process, 5 parts by mass of LBKP2 beaten to 450 mL of CSF and 95 parts by mass of NBKP2 beaten to 500 mL of CSF were used, and in the papermaking process, a long rope paper machine equipped with a Yankee dryer was used.

[0141] (Preparation of paper base layer B-9) A paper base layer B-9 was produced in the same manner as B-4, except that the paper was made using a long-rod paper machine equipped with a Yankee dryer in the papermaking process.

[0142] (Preparation of paper base layer B-10) Basis weight: 50g / m 2 Next, a paper base layer B-10 was prepared in the same manner as B-1, except that the paper thickness was set to 53 μm.

[0143] (Preparation of paper base layer B-11) Basis weight: 260g / m 2 Next, a paper base layer B-11 was prepared in the same manner as B-1, except that the paper thickness was set to 279 μm.

[0144] Example 1 The paper base layer A-1 was cut to a size of 550 mm in length x 880 mm in width, and printed using an offset printing machine (Komori Corporation's "L-644") from the side of the curl control layer where the contents will be placed to the opposite side. After printing, the coating weight on the outermost surface on which the contents are placed is 10 g / m after heat drying. 2A coating liquid prepared by mixing 100 parts by mass of an aqueous acrylic adhesive ("EM-575" manufactured by Arakawa Paint Co., Ltd.) with 3 parts by mass of a curing agent ("EM-550K" manufactured by Arakawa Paint Co., Ltd.) was applied so that the thickness of the coating liquid would be as follows: A film ("Diamilon YF1966" manufactured by Mitsubishi Chemical Corporation) that would become the thermoplastic resin layer was then dry-laminated onto the surface, with the PE layer facing outward, to obtain a film-attached mount 1 as a skin pack mount 1.

[0145] <Examples 2 to 7 and Comparative Examples 1 to 3> Examples 2 to 7 and Comparative Examples 1 to 3 were prepared in the same manner as in Example 1, except that the laminates shown in Table 2 were used. The skin pack mounts No. 3 were obtained. These skin pack mounts are examples in which the paper base layer is a single layer.

[0146] Example 8 An example in which the paper base layer is an interleaf paper will be described. One side of the laminate A-8 (the side not coated with the curl control layer) was melt-extrusion coated with MDPE ("8010" manufactured by ENEOS NUC Corporation) to a dry film thickness of 20 μm, and a paper layer B-1 was laminated to the coated surface to obtain a two-layer backing sheet. Thereafter, the sheet was cut into a size of 550 mm length x 880 mm width, and printed on the paper base layer A side and then the paper base layer B side using an offset printing machine ("L-644" manufactured by Komori Corporation). After printing, the coating weight on the outermost surface of the paper base layer A side after heat drying is 10 g / m 2 A coating liquid prepared by mixing 100 parts by mass of an aqueous acrylic adhesive ("EM-575" manufactured by Arakawa Paint Co., Ltd.) with 3 parts by mass of a curing agent ("EM-550K" manufactured by Arakawa Paint Co., Ltd.) was applied so that the thickness of the coating liquid would be as follows: A film ("Diamilon YF1966" manufactured by Mitsubishi Chemical Corporation) that would become the thermoplastic resin layer was dry-laminated on top of the coating liquid with the PE layer facing outward, to obtain a skin pack mount of Example 8.

[0147] <Examples 9 to 16 and Comparative Examples 4 to 6> The same procedures as in Example 8 were carried out except that the laminate A and paper base layer B shown in Table 2 were used, to obtain liners for skin packs of Examples 9 to 16 and Comparative Examples 4 to 6.

[0148] 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 Tables 2 and 3.

[0149] <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 work, the paper base layers A and B are used to measure the basis weight after the xylene has been sufficiently evaporated in a draft or the like and the humidity has been conditioned in a humidity-controlled environment as specified in JIS P 8111:1998.

[0150] <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.

[0151] <density> From the measured basis weight and thickness, the basis weight value (g / m 2 Calculate the density using the formula: ) ÷ paper thickness (μm).

[0152] <Ash content> The ash content was measured in accordance with JIS P 8251:2003. The paper substrate layer was ashed 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. When measuring the ash content of the paper base layer from the skin pack mount, the thermoplastic resin layer can be removed using the procedure described above. If the separated paper base layer has a pigment coating layer such as a curl control layer, the pigment coating layer was ground using an industrial razor (Feather Safety Razor Co., Ltd., "099769") until the paper surface was completely exposed. The resulting paper base layer was ashed in the same manner, and the ash content was calculated.

[0153] <Runkel ratio> The paper base layer to be measured is used after conditioning under a humidity-controlled environment specified in JIS P 8111:1998. The paper base layer is cut into 40 cm square pieces, immersed in ion-exchanged water to a concentration of 2%, and soaked for 24 hours. After 24 hours of soaking, the pulp is disintegrated into fibers using a standard disintegrator (manufactured by Kumagai Riki Kogyo Co., Ltd.) in accordance with JIS P8220-2:2012 until no undisintegrated fibers remain. The disintegrated slurry (pulp fiber dispersion) is adjusted to a solids concentration of 0.1% by mass, and the pulp solids concentration is calculated in accordance with JIS P8225:2003. The slurry after disintegration is 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 the slurry taken are used to calculate the dry weight of the sample. The resulting slurry is used to calculate the "Runkel ratio" using a fiber length measuring device ("Kajaani Fiber Lab Ver. 4.0" manufactured by Metso Automation). Using the above fiber length measuring device, the fiber wall thickness (μm) and lumen diameter (μm) are measured, and the Runkel ratio is calculated according to the following formula. (Runkel ratio) = (fiber wall thickness) x 2 / (lumen diameter) When measuring the Runkel ratio of pulp fibers constituting the paper base layer from the mount for skin packs, the paper base layer separated by the above-described procedure can be used.

[0154] <Taber stiffness> The Taber stiffness in the longitudinal and transverse directions of the mount for skin packs was measured in accordance with JIS P 8125-2:2017 (``Paper and paperboard - Test method for bending resistance - Part 2: Taber-type tester method'', established on March 21, 2017). As the measuring device, the ``Digital Taber Stiffness Tester'' manufactured by Toyo Seiki Seisakusho Co., Ltd. can be used. The sample is measured at 10 points, and the arithmetic mean value is adopted.

[0155] <Measurement of T0 and Tm by KES Compression Property Tester> The T0 value and Tm value by the KES compression property tester are measured using a commercially available compression tester, the KES-FB3-AUTO-A compression tester (manufactured by Kato Tech Co., Ltd.). Specifically, a region in the central part of the mount for skin packs is cut out to a size of 30 mm × 30 mm to obtain a sample, and the center of the measurement sample is gently sandwiched between disks positioned vertically, and the compression area (the area of the disk) is 2.0 cm 2 The thickness dimension T0 of each sample under a load of 0.49 hPa is measured. Next, the measurement sample is compressed at a pressure application rate of 0.02 mm / second until a load of 49.03 hPa is reached, and the thickness dimension Tm under a load of 49.03 hPa is measured. The sample is measured at 10 points, and the arithmetic mean value is adopted.

[0156] <Measurement of curl amount> The mount for skin packs is punched out into a rectangle of longitudinal (MD) 280 mm × transverse (CD) 180 mm, and the obtained sample for curl measurement is placed flat on a horizontal hard surface with the side of the curl adjustment layer facing down with respect to the paper base material (that is, the side of the paper base layer facing up). Then, the respective floats at the four corners of the mount are measured, and the average value thereof is taken as the numerical value. The amount of curl measured with the curl control layer side facing down is a positive (+) value. If no lifting occurs, measure the lifting by placing the paper base layer side (paper base layer B side in the case of interleaving paper) flat on a hard surface, and the amount of curl in this case is a negative (-) value.

[0157] In the examples, measurements were taken of the curl amount of the skin pack mount, as well as the curl amount of the paper substrate layer A, the curl control layer side (front side) after printing, and the paper substrate side (back side) after printing. The measured value on the paper substrate side (back side) after printing corresponds to the measured value of the skin pack mount. The curl amount is measured for a skin pack liner equivalent to 280mm length (MD) x 180mm width (CD). Therefore, when measuring a skin pack liner smaller than 280mm length (MD) x 180mm width (CD), multiply the measurement by the length-to-width ratio. Specifically, when measuring a skin pack liner that is 140mm length x 90mm width, double the value.

[0158] <Gloss measurement> The glossiness of the skin pack mount and paper base layer was measured in accordance with JIS P 8142:2005 ("Paper and paperboard - Measuring method for 75 degree specular glossiness", revised July 20, 2005). A digital gloss meter (GM-26PRO manufactured by Murakami Shikisai Giken Co., Ltd.) can be used as the measuring device. Ten samples are measured, and the arithmetic mean value is used.

[0159] <Measurement of coating amount of curl control layer on skin pack backing paper> When measuring the coating amount of the curl control layer from the mount, the following procedure is carried out. (1) Removal of the thermoplastic resin layer The mount, cut into 10cm squares, is left to stand in xylene heated to 100°C for 30 minutes to dissolve the thermoplastic resin layer. Any thermoplastic resin remaining on the surface is wiped off with a cloth, and if any remains, it is immersed in xylene again, and the process is repeated until the thermoplastic resin is completely removed. If the mount is a laminated paper, the xylene treatment separates it into laminate A, which contains the curl control layer, and paper base layer B. After this process, the xylene from laminate A is allowed to evaporate sufficiently in a draft or similar environment. (2) Removal of the paper base layer The curl control layer is ground off using an industrial razor (Feather Safety Razor Co., Ltd., model number 099769), and the coating weight is calculated from the collected mass of the curl control layer. Grinding is repeated until the paper surface is completely exposed.

[0160] The following evaluations were carried out for the Examples and Comparative Examples. (1. Printing unevenness) The paper substrate layer produced in each example and comparative example was cut to a size of 550 mm length (MD) x 880 mm width (CD), and 100 sheets of the resulting planographic samples were printed using an offset printing machine (Komori Corporation "L-644"), and the printed surface after printing was observed and evaluated according to the following criteria. 3: Fewer than 4 laminates with uneven printing 2: Print unevenness was observed on 4 or more but less than 10 laminates 1: 10 or more laminates with uneven printing

[0161] (2. Packaging suitability) The skin pack mounts produced in the Examples and Comparative Examples were punched into rectangles measuring 280 mm in length (MD) x 180 mm in width (CD). A wooden board measuring 150 mm in length x 100 mm in width x 10 mm in height was placed on 100 sheets of the skin pack mounts, and the skin packs were packaged using barrier film (manufactured by Sealed Air). In this case, packages that were not neatly packaged due to misalignment of the contents or poor adhesion of the film caused by misalignment of the mount during transportation were not packaged properly. The number of cases that were considered good was counted and evaluated according to the following criteria. 3: Fewer than 3 defective packages 2: The number of defective packages is between 3 and 5 1: 5 or more defective packages

[0162] <Buffering properties> The skin pack mounts produced in the Examples and Comparative Examples were punched into rectangles measuring 280 mm in length (MD) × 180 mm in width (CD). A 100 g square glass plate (a rectangular parallelepiped measuring 150 mm in length × 100 mm in width × 30 mm in thickness) was fixed to the center of the processed skin pack mount with packing tape, and the plate was allowed to freely drop horizontally from a height of 40 cm onto a vinyl chloride floor with the glass plate facing upward and the mount facing downward. If the glass plate was broken after the drop, the height was recorded; if it was not broken, the plate was dropped from a height 5 cm higher and again. This procedure was repeated until the glass plate broke, and the height at which it broke was recorded. The test was carried out five times, and the cushioning property was evaluated based on the average height (rounded to the nearest decimal place) according to the following criteria. 5: Will not break even if dropped from a height of 80cm or more 4: The height at the time of damage is between 70cm and 80cm 3: The height at the time of breakage is between 60cm and 70cm 2: The height at the time of damage is between 50cm and 60cm 1: The height at the time of breakage is less than 50cm

[0163] [Table 2] The "front" is the side on which the thermoplastic resin layer is formed, that is, the side on which the stored article is placed, and the "back" is the opposite side.

[0164] [Table 3] In the table, the curl amount of the mount is the same as the curl amount after back printing.

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 curl control layer, and the paper base layer in this order; The curl adjusting layer contains a pigment and has a coating weight of 4.0 g / m ２ That's all, the skin pack mount is curled so that the paper base layer is on the inside with respect to the curl control layer, A sample cut out from the center of the skin pack mount was measured using a KES compression property tester, and the compression area was 2.0 cm ２ The thickness dimension of the sample under a load of 0.49 hPa is defined as T0, and the sample is further compressed at a pressure rate of 0.02 mm / sec until it is under a load of 49.03 hPa. The thickness dimension of the sample under a load of 49.03 hPa is defined as Tm. A skin pack mount characterized in that the value of T0-Tm is 0.10 to 3.00 mm.

2. 2. The skin pack mount according to claim 1, wherein the Runkel ratio of the pulp fibers constituting the paper base layer is 0.50 to 1.

50.

3. The skin pack mount according to claim 1, wherein the paper base layer has an ash content of 10.0% by mass or less.

4. 2. The skin pack mount according to claim 1, wherein the glossiness of the skin pack mount measured from the paper base layer side is 5% or more.

5. The paper base layer is an interleaving paper including, from the curl control layer side, a paper base layer A, an adhesive layer, and a paper base layer B, The skin pack liner according to claim 1, wherein when the basis weight of the paper base layer A is basis weight A and the basis weight of the paper base layer B is basis weight B, the ratio of the basis weight A to the basis weight B (basis weight A / basis weight B) is 3.0 to 7.

0.

6. 2. The skin pack mount according to claim 1, wherein the amount of curl of the skin pack mount equivalent to a length (MD) of 280 mm and a width (CD) of 180 mm is 2 to 22 mm.

7. 2. The skin pack mount according to claim 1, wherein the thickness of the skin pack mount is 400 to 900 μm.

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