Packaging bag and sheet packaging body

Abstract

A packaging bag for accommodating a sheet laminate in which a plurality of sheets are laminated, the density of the sheet laminate being 0.09 g / cm3 or more and 0.50 g / cm3 or less, the packaging bag being configured from a base material containing a paper component, the first static friction coefficient of the inner surface of the base material disposed on the inner side of the packaging bag being 0.25 or more and 0.5 or less, and the second static friction coefficient of the inner surface of the base material being 0.25 or more and 0.5 or less. The second coefficient of static friction of the outer surface of the base material disposed on the outside of the packaging bag is 0.3 or more and 0.65 or less, and the ratio of the first coefficient of static friction to the second coefficient of static friction is 0.5 or more and 0.9 or less.

Description

Technical Field

[0001] The invention relates to a packaging bag and a sheet packaging body. Background Art

[0002] Sheet material packages containing sheet materials such as tissues or toilet paper are circulated and used in a state where a plurality of sheets are contained in a packaging bag made of resin film (e.g., Patent Documents 1 and 2). In recent years, from the viewpoint of suppressing environmental loads such as global warming associated with CO2 emissions and marine pollution such as microplastics, there has been an active trend to change the packaging bag used for sheet material packages from resin to paper to reduce the amount of resin used in the packaging bag.

[0003] <Prior Art Literature>

[0004] <Patent Documents>

[0005] Patent Document 1: Japanese Patent Application Publication No. 2008-183034

[0006] Patent Document 2: Japanese Patent Application Publication No. 2018-177364 Summary of the invention

[0007] <Problems to be Solved by the Invention>

[0008] However, since paper packaging bags are less flexible than resin packaging bags, when holes for opening are provided, the holes are difficult to tear and opening is difficult.

[0009] An object of the present invention is to provide a paper packaging bag that is easy to open.

[0010] <Methods used to solve the problem>

[0011] A packaging bag according to one embodiment of the present invention is a packaging bag for accommodating a sheet stack formed by stacking a plurality of sheets, wherein the density of the sheet stack is 0.09 g / cm 3 Above and 0.50g / cm 3 Below, the packaging bag is composed of a substrate containing a paper component, the first static friction coefficient of the inner surface of the substrate arranged on the inner side of the packaging bag is greater than 0.25 and less than 0.5, the second static friction coefficient of the outer surface of the substrate arranged on the outer side of the packaging bag is greater than 0.3 and less than 0.65, and the ratio of the first static friction coefficient to the second static friction coefficient is greater than 0.5 and less than 0.9.

[0012] <Effects of the Invention>

[0013] According to one aspect of the present invention, a paper packaging bag that is easy to open can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a figure which shows the sheet material package which accommodates a sheet material in a packaging bag.

[0015] Figure 2 It is a figure which shows the sheet material accommodated in the packaging bag.

[0016] Figure 3 Viewed from the top side Figure 1 Figure 2. Sheet packaging body.

[0017] Figure 4 Viewed from the bottom side Figure 1 Figure 2. Sheet packaging body.

[0018] Figure 5 Observed from the front side Figure 1 Figure 2. Sheet packaging body.

[0019] Figure 6 Observed from the back side Figure 1 Figure 2. Sheet packaging body.

[0020] Figure 7 Viewed from the left side Figure 1 Figure 2. Sheet packaging body.

[0021] Figure 8 Viewed from the right side Figure 1 Figure 2. Sheet packaging body.

[0022] Fig. 9 This is a diagram showing an example of a cross section of a base material of a packaging bag.

[0023] Fig.10 This is a diagram showing a state where the packaging bag of the sheet packaging body is opened.

[0024] Fig.11 It is a figure which shows the usage state of a sheet material package. DETAILED DESCRIPTION

[0025] <Packaging>

[0026] The embodiments of the present invention are described in detail with reference to the accompanying drawings. In each figure, the same symbols are sometimes marked on common parts and the description is omitted. In addition, in each figure, the scale of each part may be different from the actual one. It should be noted that in each figure, a three-dimensional orthogonal coordinate system of three-axis directions (X direction, Y direction, Z direction) is used, the length direction of the packaging bag is set to the X direction, the width direction is set to the Y direction, and the height direction (up and down direction or thickness direction) is set to the Z direction.

[0027] Figure 1It is a figure which shows the sheet material package which accommodated the sheet material in the packaging bag of embodiment. Figure 2 It is a figure which shows the sheet material accommodated in the packaging bag of embodiment. Figure 3 , Figure 4 , Figure 5 , Figure 6 , Figure 7 , Figure 8 Observe from the top, bottom, front, back, left, and right sides Figure 1 Figure 2. Sheet packaging body.

[0028] like Figure 1 and Figure 2 As shown, the sheet package 100 has a packaging bag 10 and a sheet stack 20 (sheet S). The sheet package 100 is an example of a sheet package according to the present embodiment. In addition, the packaging bag 10 is an example of a packaging bag constituting the sheet package according to the present embodiment. The sheet stack 20 is an example of a sheet stack contained in the packaging bag according to the present embodiment.

[0029] like Figure 2 As shown in FIG. 1 , a plurality of stacked sheets S (a sheet stack 20) ​​are contained in the packaging bag 10. The sheet stack 20 is contained in the packaging bag 10 in such a manner that the stacking direction (SD direction) of the sheets S is the height direction (Z direction). The sheet stack 20 can be pulled out one by one through a take-out port (opening OP) formed in the packaging bag 10 to be described later (see FIG. 1 ). Fig.11 ).

[0030] There is no particular limitation on the form of the sheet stack 20, and for example, the form may be a form in which the sheets S are stacked in a folded state, a form in which the sheets S are stacked alternately in a folded state (a so-called pop-up sheet stack), a form in which a plurality of sheets S are simply stacked, etc.

[0031] In addition, regarding the size of the sheet S (sheet stack 20), when the sheet S is folded, the length L2 of the packaging bag 10 in the longitudinal direction (X direction) can be set to about 150 to 250 mm, the width W2 in the width direction (Y direction) perpendicular to the longitudinal direction (X direction) of the packaging bag 10 can be set to about 70 to 150 mm, and the height H2 in the height direction (Z direction) can be set to about 20 to 100 mm (see Figure 2 , Figure 3 ). Such laminated sheets of paper can be produced, for example, by means of a rotary or multi-station interfolding machine.

[0032] The density of the sheet stack is 0.09 g / cm 3 Above and 0.50g / cm 3Below, preferably 0.13 g / cm 3 Above and 0.40g / cm 3 Below, more preferably 0.15g / cm 3 Above and 0.30g / cm 3 The density of the sheet laminate was measured in accordance with the provisions of JIS P8118 (2014).

[0033] The form of the sheet S is not particularly limited, and the sheet S may be applied to, for example, tissue paper, kitchen paper, toilet paper, toilet paper, and other sanitary thin papers, including sanitary thin papers containing moisturizing ingredients (such as lotion tissues).

[0034] The use of the sheet material S is not particularly limited, and the sheet material S may be used for any of industrial, household, and portable uses. It should be noted that the sheet material S in the present embodiment is preferably used for household or portable paper towels.

[0035] There is no particular limitation on the number of layers of sheet material S, which can be more than one layer, preferably one or two layers (two overlapping sheets). In addition, there is no particular limitation on the shape of sheet material S, and preferably, for example, the contour shape of a two-layer sheet in a folded state is a quadrilateral (rectangular, square, etc.).

[0036] There is no particular limitation on the material of the sheet material S. For example, a sheet material such as paper, nonwoven fabric or cloth can be used, preferably paper (paper sheet material). It should be noted that when the sheet material S is a paper sheet material, base paper with pulp as the main raw material is used. The pulp composition can use a known composition in paper sheets. For example, the mixing ratio of the pulp can be 50% by mass or more, preferably 90% by mass or more, and more preferably 100% by mass.

[0037] The pulp composition of the sheet S (paper sheet) is not particularly limited. For example, conifer pulp such as NBKP (conifer kraft pulp) or NUKP (conifer unbleached pulp) and broadleaf pulp such as LBKP (broadleaf kraft pulp) or LUKP (broadleaf unbleached pulp) may be used in any ratio.

[0038] It should be noted that the ratio of broadleaf pulp to coniferous pulp in the sheet S (paper sheet) is not limited, but is preferably 10:90 to 80:20, and more preferably a pulp composition in which the ratio of coniferous pulp to broadleaf pulp is larger. In addition, the pulp contained in the sheet S (paper sheet) may also be waste paper pulp.

[0039] The basis weight of the sheet S is not particularly limited, but depends on the number of layers. In the case of paper, it is 5 g / m 2 Above and 80g / m 2 Below, preferably 10g / m2 Above and 60g / m 2 Below, more preferably 10g / m 2 Above and 45g / m 2 In addition, in the case of nonwoven fabric, it is preferably 20 g / m 2 Above and 100g / m 2 The basis weight is measured in accordance with the provisions of JIS P8124 (2011).

[0040] In addition, the thickness of the sheet material S (paper sheet material) is not particularly limited, and the paper thickness measured under the environment of JIS P 8111 (1998) can be used. For example, when the sheet material S is paper, the paper thickness of each two layers is 50 μm or more and 600 μm or less, preferably 60 μm or more and 500 μm or less, and more preferably 130 μm or more and 400 μm or less.

[0041] In addition, the sheet S (paper sheet) may be embossed. Such embossing can be performed by a known embossing method.

[0042] There is no particular limitation on the shape of the packaging bag 10. The packaging bag 10 of the present embodiment has a top surface 11, a bottom surface 12, a side surface 13, a side surface 14, a short side surface 15, and a short side surface 16 when the sheet S (sheet stack 20) ​​is contained therein. It should be noted that in the packaging bag 10, the top surface 11 and the bottom surface 12 are opposite to each other in the vertical direction (Z direction), the side surface 13 and the side surface 14 are opposite to each other in the width direction (Y direction), and the short side surface 15 and the short side surface 16 are opposite to each other in the length direction (X direction). In addition, the short side surfaces 15 and 16 are continuous with any one of the top surface 11, the bottom surface 12, the side surface 13, and the side surface 14 ( Figure 1 , Figure 3 to Figure 8 ).

[0043] There is no particular limitation on the size of the packaging bag 10. For example, the length L1 of the packaging bag 10 in the longitudinal direction (X direction) can be set to about 150 to 250 mm, the width W1 in the width direction (Y direction) perpendicular to the longitudinal direction (X direction) of the packaging bag 10 can be set to about 70 to 150 mm, and the height H1 in the height direction (Z direction) can be set to about 20 to 100 mm ( Figure 1 , Figure 3 It should be noted that the dimensions of the packaging bag 10 represent the dimensions when the sheet stack 20 is contained in the packaging bag 10 ( Figure 1 , Figure 2 ).

[0044] A take-out opening extending in the longitudinal direction (X direction) of the packaging bag 10 is formed on the top surface 11 of the packaging bag 10, the top surface 11 side of the short side surface 15, and the top surface 11 side of the short side surface 16. Specifically, the take-out opening is formed by a tearing cut line 30. The tearing cut line 30 is a cut line in which the cut portions C and the connecting portions T (the uncut portion between the two cut portions C and C) are alternately arranged, and when the connecting portion T is broken, two adjacent cut portions C become a continuous cut portion ( Figure 1 , Figure 3 , Figure 7 , Figure 8 ).

[0045] In this embodiment, the cleavage cut line 30 is composed of a linear eyelet M ( Figure 1 , Figure 3 , Figure 7 , Figure 8 The ratio of the connecting portion T to the cutting portion C of the cleavage incision line 30 (eyelet) is arbitrary, and may be, for example, 1:1 to 1:7, preferably 1:1.3 to 1:5, and more preferably 1:1.5 to 1:3.

[0046] In the packaging bag 10 of the present embodiment, the cleavage cut line 30 (perforations M) is cleaved, thereby forming a take-out port (opening OP) for pulling out the sheet S on the top surface 11 of the packaging bag 10 ( Figure 1 , Fig.10 ).

[0047] It should be noted that although Figure 1 , Figure 3 , Figure 7 , Figure 8 In the example shown, the removal opening (cleavage cut line 30) is formed on the top surface 11 and continuously extends from the top surface 11 to the top surface 11 side of the short side surface 15 and the top surface 11 side of the short side surface 16, but the invention is not limited to this form. As other forms of the removal opening 30, for example, it may be a form extending from the end edge of the short side surface 15 side of the top surface 11 to the end edge of the short side surface 16 side of the top surface 11 (not shown), or it may be a form continuously extending from the inner side of the end edge of the short side surface 15 side of the top surface 11 to the inner side of the end edge of the short side surface 16 side of the top surface 11 (not shown).

[0048] It should be noted that the method for making the cleavage line 30 is arbitrary. For example, although not shown, the cleavage line 30 can be formed by placing a base material BS of the packaging bag 10 described later between the needle and the platform, and inserting the tip of the needle into the receiving groove of the platform.

[0049] Ventilation holes (not shown) may be formed in the packaging bag 10. The vents may function as air holes in the packaging bag 10. There is no particular limitation on the position of the vents. In the present embodiment, the vents may be provided on the side 13, the side 14, and the short sides 15 and 16 of the packaging bag 10. There is no limitation on the number of vents. In addition, there is no limitation on the shape of the vents, for example, they may be circular in a top view. In addition, there is no limitation on the size of the vents, for example, the diameter may be approximately 2 mm.

[0050] It should be noted that the method for making the vent hole is arbitrary. For example, similar to the above-mentioned cleavage incision line 30, the vent hole can be formed by placing the base material BS of the packaging bag 10 between the needle part and the platform part, and inserting the tip of the needle part toward the receiving groove of the platform part. It should be noted that when forming the vent hole, a device without a receiving groove on the platform part can also be used.

[0051] By providing such vent holes in the packaging bag 10 , the packaging bag is less likely to be broken when the sheet package 100 is stored or transported.

[0052] There is no particular limitation on the packaging form of the packaging bag 10. For example, a packaging bag (pillow-type packaging bag) may be used in which the base material BS of the packaging bag 10 is processed into a cylindrical shape and the open end of the cylindrical base material BS is sealed (closed), a packaging bag (candy-type packaging bag) may be used in which both ends of the sheet of the cylindrical packaging bag 10 are folded and sealed (closed), or a packaging bag formed by combining the above, etc. It should be noted that in the case of a pillow-type packaging bag, the cylindrical base material BS may be folded into a gusseted shape.

[0053] In this embodiment, the packaging bag 10 is composed of a pillow-type packaging bag having at least one sealing portion. Specifically, sealing portions (end seals) 40 and 50 are formed on the short sides 15 and 16 of the packaging bag 10, and a sealing portion (bottom seal) 60 is formed on the bottom surface 12 of the packaging bag 10, so as to perform pillow packaging on the sheet S (sheet stack 20).

[0054] In the packaging bag 10 according to the present embodiment, the seals 40, 50, 60 are heat-fused. Here, heat-fusion means that parts of the packaging bag sheet are fused to each other by heating a part of the base material BS. Specifically, the seals 40, 50, 60 are heat-fused in a state where an inner layer (resin layer) 10B of the base material BS described later is arranged inside the packaging bag 10.

[0055] In the packaging bag 10 , the joining pitches of the seals 40 , 50 , and 60 are each preferably 0.5 mm to 2 mm, more preferably 0.8 mm to 1.8 mm, and even more preferably 1.0 mm to 1.5 mm.

[0056] Here, the joining pitch refers to the spacing between the portions (not shown) bonded in a convex shape in a predetermined direction (the width direction (Y direction) of the packaging bag 10 for the sealing portions 40 and 50 and the length direction (X direction) of the packaging bag 10 for the sealing portion 60) when viewed from one side of the sealing portions 40, 50, and 60 (for example, the bottom surface 12 side of the packaging bag 10).

[0057] In the present embodiment, as described above, by setting the bonding pitch of the sealing portion (sealing portions 40, 50, 60) to be greater than 0.5 mm and less than 2 mm, the bonding function of the inner layer (resin layer 10B) provided on the base layer (paper layer) 10A described later can be improved, thereby obtaining a packaging bag 10 (pillow-type packaging bag) with higher sealing properties.

[0058] The packaging bag 10 is made of a base material BS containing a paper component. Here, the paper component is a component (pulp) formed by gluing plant fibers. There is no limitation on the composition of the pulp in the paper component. For example, the ratio of broadleaf pulp to coniferous pulp is 0:100 to 70:30, and preferably the pulp composition has a larger ratio of coniferous pulp to broadleaf pulp. In addition, waste paper pulp may be used.

[0059] The base material BS constituting the packaging bag 10 of the first embodiment is composed of a base layer 10A, an inner layer 10B, and an outer layer 10C. The base material BS in the first embodiment has a three-layer structure in which the inner layer 10B and the outer layer 10C are stacked on each side of the paper layer 10A. Fig. 9 ).

[0060] The base layer 10A constitutes the base of the substrate BS. In addition, the base layer 10A constitutes a paper layer containing the above-mentioned paper component. That is, the substrate BS includes the base layer 10A containing the paper component.

[0061] The material of the paper component included in the base layer (paper layer) 10A is not particularly limited, and may be formed of, for example, kraft paper or rayon paper.

[0062] Here, kraft paper is paper made of kraft pulp as a raw material. In addition, rayon paper is made by mixing rayon fibers produced by chemical synthesis of wood pulp and the like with kraft pulp. It should be noted that from the viewpoint of taking both the softness and strength of the packaging bag 10 into consideration, it is preferred that the blending ratio of rayon fibers is 20% or less by mass.

[0063] The basis weight of the base layer (paper layer) 10A is not limited, but is preferably 10 g / m 2 Above and 70g / m 2 Below, more preferably 15g / m 2 Above and 60g / m 2 Below, more preferably 20g / m 2 Above and 50g / m 2 The basis weight is measured in accordance with the provisions of JIS P 8124 (2011).

[0064] The thickness of the base layer (paper layer) 10A is not limited, but is preferably 20 μm to 300 μm, more preferably 30 μm to 200 μm, and further preferably 40 μm to 180 μm. The thickness is measured according to JIS P 8118 (2014).

[0065] There is no limitation on the tensile strength of the base layer (paper layer) 10A. For example, it is 500 cN / m or more and 20,000 cN / m or less in the longitudinal direction of the fiber (flow direction or MD direction), preferably 1,000 cN / m or more and 15,000 cN / m or less, and more preferably 1,500 cN / m or more and 12,000 cN / m or less.

[0066] In addition, in the transverse direction of the fiber (direction orthogonal to the flow direction or CD direction), it is 100 cN / m or more and 10000 cN / m or less, preferably 300 cN / m or more and 7000 cN / m or less, and more preferably 500 cN / m or more and 4000 cN / m or less. It should be noted that the tensile strength is measured according to the provisions of JIS P 8113 (2006).

[0067] There is no limitation on the elongation of the base layer (paper layer) 10A, for example, in the longitudinal direction (MD direction) of the fiber, it is 0.5% or more and 30% or less, preferably 1% or more and 25% or less, and more preferably 2% or more and 20% or less. In addition, in the transverse direction (CD direction) of the fiber, it is 0.5% or more and 20% or less, 1% or more and 10% or less, and 2% or more and 5% or less. It should be noted that the elongation is measured in accordance with the provisions of JIS P 8113 (2006).

[0068] The tear strength of the base layer (paper layer) 10A is not limited, but is, for example, 50 mN to 500 mN in the longitudinal direction (MD direction) of the fiber, preferably 80 mN to 480 mN, and more preferably 100 mN to 450 mN.

[0069] In the transverse direction (CD direction) of the fiber, it is 50 mN to 1000 mN, preferably 80 mN to 900 mN, and more preferably 100 mN to 800 mN. The tear strength is measured in accordance with JIS P8116 (2000).

[0070] The inner layer 10B is laminated on one surface of the base layer (paper layer) 10A and constitutes a resin layer containing a thermoplastic resin. The inner layer (resin layer) 10B is arranged on the inner side of the packaging bag 10. Here, the inner side of the packaging bag 10 refers to the side where the base material BS of the packaging bag 10 contacts the sheet material S contained in the packaging bag 10 (that is, the side where the sheet material S is contained in the packaging bag 10 or the side of the base material BS where the inner layer 10B is formed).

[0071] The inner surface IS of the base material BS arranged on the inner side of the packaging bag 10 (the side where the sheet material S is contained in the packaging bag 10) is formed on the inner layer 10B. It should be noted that the inner surface IS of the base material BS arranged on the inner side of the packaging bag 10 corresponds to the surface on the side where the base material BS and the sheet material S contained in the packaging bag 10 are in contact (that is, the side of the base material BS where the inner layer 10B is formed or the side opposite to the side of the base material BS where the outer layer is formed).

[0072] The material of the thermoplastic resin contained in the inner layer (resin layer) 10B is not particularly limited, but is preferably low-density polyethylene. The low-density polyethylene may be high-pressure low-density polyethylene (LDPE) or linear low-density polyethylene (L-LDPE).

[0073] The thickness of the inner layer (resin layer) 10B is not limited, but is preferably 5 μm to 40 μm, more preferably 7 μm to 35 μm, and further preferably 9 μm to 30 μm. The paper thickness is measured according to JIS P8118 (2014).

[0074] The thermoplastic resin contained in the inner layer (resin layer) 10B contains a slip agent. Here, the slip agent is an additive that reduces the friction coefficient of the surface (inner face) of the inner layer 10B. In the present embodiment, the slip agent is added to the thermoplastic resin contained in the inner layer (resin layer) 10B, but it may also be applied to the inner face IS of the base material BS.

[0075] There is no particular limitation on the composition of the lubricant, and for example, ethylene homopolymer, fatty acid amide, vegetable oil, etc. can be used as the main component. It should be noted that there is no particular limitation on the content of the lubricant relative to the thermoplastic resin. In addition, in addition to the main component, the lubricant may also contain additives for the purpose of maintaining the stability of the lubricant.

[0076] In this embodiment, since the base material BS of the packaging bag 10 includes a base layer 10A containing a paper component and an inner layer 10B laminated on one surface of the base layer 10A and arranged on the inner side of the packaging bag 10, and the inner layer 10B contains a thermoplastic resin containing a slip agent, the friction force (static friction coefficient) between the base material BS and the sheet S can be reduced. Therefore, since the base material BS slides easily relative to the sheet S, when the perforations M are provided on the paper packaging bag 10, the perforations M are easily torn, and even the paper packaging bag 10 is easy to open ( Figure 1 , Fig.10 ).

[0077] The outer layer (printed layer) 10C is provided on the other side of the paper layer 10A and constitutes a printed layer printed on the surface of the packaging bag. The outer layer (printed layer) 10C is arranged on the outside of the packaging bag 10. Here, the outside of the packaging bag 10 refers to the side of the base material BS of the packaging bag 10 that is not in contact with the sheet material S contained in the packaging bag 10 (that is, the side opposite to the side where the sheet material S is contained in the packaging bag 10 or the side of the base material BS where the inner layer 10B is formed).

[0078] The outer layer (printed layer) 10C forms the outer surface OS of the base material BS arranged on the outer side of the packaging bag 10 (the side opposite to the side where the sheet material S is contained in the packaging bag 10). It should be noted that the outer surface OS of the base material BS arranged on the outer side of the packaging bag 10 corresponds to the surface on the side that is not in contact with the sheet material S contained in the packaging bag 10 (that is, the surface of the base material BS on the side where the outer layer 10C is formed or the surface of the base material BS on the side opposite to the side where the inner layer 10B is formed).

[0079] The outer layer (printed layer) 10C contains an anti-slip agent. Here, the anti-slip agent is an additive that increases the friction coefficient of the surface (outer surface) of the outer layer 10C. In this embodiment, the anti-slip agent is applied to the outer surface OS of the base material BS, but it can also be contained in the outer layer (printed layer) 10C.

[0080] There is no particular limitation on the composition of the anti-slip agent, and for example, colorless ink (synthetic resin), oily primer, etc. can be used as the main component. It should be noted that there is no particular limitation on the amount of the anti-slip agent used in the outer layer (printing layer) 10C. In addition, in addition to the main component, the anti-slip agent may also contain an auxiliary agent or a solvent for the purpose of maintaining the stability of the anti-slip agent.

[0081] In the present embodiment, since the base material BS of the packaging bag 10 includes a base layer 10A containing a paper component and an outer layer 10C laminated on the other surface of the base layer 10A and arranged on the outside of the packaging bag 10, and the outer layer 10C contains an anti-slip agent, it is possible to increase the friction generated between the outer layer 10C of the base material BS and the finger of a person touching the outer layer 10C of the base material BS (hereinafter referred to as the finger). As a result, since the finger touching the base material BS becomes less likely to slide relative to the base material BS, and the base material BS becomes more likely to slide relative to the sheet stack 20 (sheet S), when the sheet S is provided on the paper packaging bag 10, the sheet S is easily torn, and even the paper packaging bag 10 is easy to open ( Figure 1 , Fig.10 ).

[0082] In the present embodiment, the ratio of the paper component in the packaging bag 10 (base material BS) is 50% or more.

[0083] The basis weight of the packaging bag 10 (base material BS) is not limited, but is preferably 20 g / m 2 Above and 100g / m 2 Below, more preferably 25g / m 2 Above and 70g / m 2 Below, more preferably 30g / m 2 Above and 60g / m 2 The basis weight is measured in accordance with the provisions of JIS P 8124 (2011).

[0084] The thickness (paper thickness) of the packaging bag 10 (substrate BS) is not limited, and is, for example, 25 μm to 350 μm, preferably 30 μm to 250 μm, and more preferably 45 μm to 200 μm. The thickness may be measured in accordance with JIS P 8118 (2014).

[0085] The tensile strength of the packaging bag 10 (base material BS) is not limited, and is, for example, 1000 cN / m to 20000 cN / m in the longitudinal direction (MD direction) of the fiber, preferably 1500 cN / m to 18000 cN / m, and more preferably 2000 cN / m to 15000 cN / m.

[0086] In addition, in the transverse direction (CD direction) of the fiber, it is 500 cN / m or more and 10000 cN / m or less, preferably 1000 cN / m or more and 8000 cN / m or less, and more preferably 1500 cN / m or more and 5000 cN / m or less. It should be noted that the tensile strength is measured according to the provisions of JIS P 8113 (2006).

[0087] The elongation of the packaging bag 10 (base material BS) is not limited, and is, for example, 0.5% to 30% in the longitudinal direction (MD direction) of the fiber, preferably 1% to 25%, and more preferably 2% to 20%. In addition, in the transverse direction (CD direction) of the fiber, it is 0.5% to 20%, 1% to 10%, or 1.5% to 5%. It should be noted that the elongation is measured in accordance with the provisions of JIS P 8113 (2006).

[0088] The tear strength of the packaging bag 10 is not limited, but is, for example, 50 mN to 500 mN, preferably 80 mN to 450 mN, and more preferably 100 mN to 400 mN in the longitudinal direction (MD direction) of the fiber.

[0089] In the transverse direction (CD direction) of the fiber, it is 200 mN to 1000 mN, preferably 250 mN to 900 mN, and more preferably 300 mN to 800 mN. The tear strength is measured in accordance with JIS P8116 (2000).

[0090] The Taber stiffness of the packaging bag 10 (base material BS) is not limited, and is, for example, 0.01 mN / m to 0.20 mN / m in the longitudinal direction (MD direction) of the fiber, preferably 0.02 mN / m to 0.17 mN / m, and more preferably 0.03 mN / m to 0.15 mN / m.

[0091] In the transverse direction (CD direction) of the fiber, it is 0.001 mN / m to 0.2 mN / m, preferably 0.01 mN / m to 0.15 mN / m, and more preferably 0.02 mN / m to 0.13 mN / m. The Taber rigidity is measured in accordance with JIS P 8125 (2000).

[0092] In the packaging bag 10 of the present embodiment, the inner surface IS of the base material BS disposed inside the packaging bag 10 (the inner surface IS of the base material BS on the side where the inner layer 10B is formed) has a first static friction coefficient A. The first static friction coefficient A is 0.25 or more and 0.5 or less, preferably 0.27 or more and 0.48 or less, and more preferably 0.3 or more and 0.45 or less.

[0093] In this specification, the static friction coefficient refers to the ratio of the friction force generated on the contact surface of two objects in a state of no relative motion to the force acting on the contact surface at right angles. The static friction coefficient is measured according to the horizontal method specified in JIS P 8147 (2010).

[0094] The first static friction coefficient A can be defined as the coefficient of friction between the inner surface IS of the substrate BS and the sheet S (basic weight 33 g / m 2 In this case, the static friction coefficient A1 is greater than or equal to 0.3 and less than or equal to 0.5, preferably greater than or equal to 0.33 and less than or equal to 0.48, and more preferably greater than or equal to 0.35 and less than or equal to 0.45.

[0095] The first static friction coefficient A can be defined as the static friction coefficient A2 generated between the inner surface IS of the substrate BS and the aluminum foil (thickness 20 μm). In this case, the static friction coefficient A2 is 0.25 to 0.5, preferably 0.27 to 0.48, and more preferably 0.3 to 0.45.

[0096] The outer surface OS of the substrate BS disposed outside the packaging bag 10 (the outer surface OS of the substrate BS on the side where the outer layer 10C is formed) has a second static friction coefficient B. The second static friction coefficient B is 0.3 to 0.65, preferably 0.35 to 0.63, and more preferably 0.4 to 0.6.

[0097] The second static friction coefficient B can be defined as the coefficient of friction between the outer surface OS of the substrate BS and the sheet S (basic weight 33g / m 2 In this case, the static friction coefficient B1 is greater than or equal to 0.5 and less than or equal to 0.65, preferably greater than or equal to 0.52 and less than or equal to 0.6, and more preferably greater than or equal to 0.54 and less than or equal to 0.57.

[0098] The second static friction coefficient B can be defined as the static friction coefficient B2 generated between the outer surface OS of the substrate BS and the aluminum foil (thickness 20 μm). In this case, the static friction coefficient B2 is 0.3 to 0.54, preferably 0.35 to 0.53, and more preferably 0.4 to 0.52.

[0099] In the packaging bag 10 of the present embodiment, the ratio of the first static friction coefficient A to the second static friction coefficient B is 0.5 or more and 0.9 or less, preferably 0.55 or more and 0.89 or less, and more preferably 0.6 or more and 0.87 or less. Here, the ratio of the first static friction coefficient A to the second static friction coefficient B represents the ratio of the first static friction coefficient A to the second static friction coefficient.

[0100] It should be noted that when the first static friction coefficient A is static friction coefficient A1 and the second static friction coefficient B is static friction coefficient B1, the ratio of static friction coefficient A1 to static friction coefficient B1 is greater than 0.6 and less than 0.85, preferably greater than 0.65 and less than 0.83, and more preferably greater than 0.7 and less than 0.8.

[0101] In addition, when the first static friction coefficient A is the static friction coefficient A2 and the second static friction coefficient B is the static friction coefficient B2, the ratio of the static friction coefficient A2 to the static friction coefficient B2 is 0.5 or more and 0.9 or less, preferably 0.55 or more and 0.89 or less, and more preferably 0.6 or more and 0.87 or less.

[0102] It should be noted that the base material BS having such a static friction coefficient may be formed on the entire surface of the packaging bag 10 or may be formed only on the surface where the holes M are formed (eg, the top surface 11 of the packaging bag).

[0103] In this embodiment, as described above, for a density of 0.09 g / cm 3 Above and 0.50g / cm 3 In the following sheet laminate 20, the first static friction coefficient A of the substrate inner surface IS is 0.25 or more and 0.5 or less, the second static friction coefficient B of the substrate outer surface OS is 0.3 or more and 0.65 or less, and the ratio of the first static friction coefficient A to the second static friction coefficient is 0.5 or more and 0.9 or less. Thus, a certain friction force is generated on the inner surface IS of the substrate BS constituting the packaging bag 10, and a friction force greater than the friction force generated on the inner surface IS of the substrate BS is generated on the outer surface OS of the substrate BS.

[0104] Therefore, the friction force generated on the inner surface IS of the substrate BS is relatively small on the inner surface IS of the substrate and relatively large on the outer surface OS of the substrate, based on the same sheet stack 20 ( Fig. 9 In such a structure, since the finger touching the substrate BS does not easily slide relative to the substrate BS, when the perforations M are provided on the paper packaging bag 10, the perforations M are easily torn, and even the paper packaging bag 10 is easy to be opened ( Figure 1 , Fig.10 ).

[0105] It should be noted that in this embodiment, since the first static friction coefficient A of the inner surface IS of the substrate BS disposed inside the packaging bag 10 is 0.25 or more and 0.5 or less, the inner surface IS of the substrate BS containing a paper component is in a state where it is easy to slide relative to the sheet S. Therefore, the perforations M provided on the paper packaging bag 10 are easier to tear, making it easier to open the packaging bag 10 ( Figure 1 , Fig.10 ).

[0106] In addition, since the ratio of the first static friction coefficient A to the second static friction coefficient B is set to 0.5 or more and 0.9 or less, the difference between the friction coefficient of the inner surface IS of the substrate BS with respect to the sheet S contained in the packaging bag 10 and the friction coefficient of the outer surface OS of the substrate BS becomes larger. Therefore, the perforations M provided in the paper packaging bag 10 are more likely to be torn, making it easier to open the packaging bag 10.

[0107] It should be noted that, in a paper packaging bag, in order to improve the opening property, the difference between the first static friction coefficient A and the second static friction coefficient B is preferably as large as possible. On the other hand, if the second static friction coefficient B is too large relative to the first static friction coefficient A, the perforations M provided on the paper packaging bag 10 may be torn before the packaging bag 10 is opened (for example, during the manufacture, circulation, storage, etc. of the sheet packaging body 100 using the packaging bag 10).

[0108] Therefore, in this embodiment, the second static friction coefficient B is set to be greater than or equal to 0.3 and less than or equal to 0.65, so that the second static friction coefficient B is adjusted so as not to make the outer surface OS of the substrate BS too difficult to slide, thereby preventing the packaging bag 10 from accidentally breaking without reducing the opening property of the packaging bag 10.

[0109] In the packaging bag 10 of the present embodiment, the first static friction coefficient A and the second static friction coefficient B correspond to the static friction coefficients between the base material BS in the CD direction and the sheet S in the MD direction.

[0110] It should be noted that, in the present embodiment, the MD direction of the substrate BS corresponds to the length direction (X direction) of the packaging bag 10, and the CD direction of the substrate BS corresponds to the width direction (Y direction) of the packaging bag 10 ( Figure 1 , Figure 3 to Figure 8 ). In addition, the MD direction of the sheet S corresponds to the width direction (Y direction) of the packaging bag 10 or the sheet stack 20, and the CD direction of the sheet S corresponds to the length direction (X direction) of the packaging bag 10 or the sheet stack 20 ( Figure 1 , Figure 2 ).

[0111] In this embodiment, the static friction coefficient between the CD direction of the inner surface IS of the substrate and the MD direction of the sheet is set to the first static friction coefficient, so that the CD direction of the inner surface of the substrate becomes easy to slide relative to the MD direction of the sheet. In addition, the static friction coefficient between the CD direction of the outer surface OS of the substrate and the MD direction of the sheet is set to the second static friction coefficient, so that the CD direction of the outer surface OS of the substrate becomes difficult to slide relative to the finger touching the substrate.

[0112] Thus, when the sheet S is contained in the packaging bag 10 so that the MD direction of the sheet is along the CD direction of the base material and the perforations M are formed in the MD direction of the base material, when the surface of the packaging bag on which the perforations M are formed is pressed with the thumbs of both hands and the thumbs are moved in a separated manner in the CD direction of the base material, the perforations M are ruptured. At this time, since the perforations M are easily ruptured with a small force, it becomes easier to open the packaging bag 10.

[0113] In the packaging bag 10 of the present embodiment, as described above, the cleavage cut lines 30 (perforations M) are formed on the top surface 11 of the packaging bag 10 along the MD direction of the base material BS.

[0114] In the present embodiment, since a tearing cut line 30 (hole M) is formed on the top surface 11 of the packaging bag 10 along the MD direction of the base material BS, the tearing cut line 30 (hole M) can be torn by simply pressing the top surface 11 of the packaging bag 10 with the thumbs of both hands and moving the thumbs in a separate manner in the CD direction of the base material BS, so that the packaging bag 10 can be easily opened.

[0115] In addition, in the present embodiment, the cleavage cut line 30 (perforations M) formed on the top surface 11 of the packaging bag 10 can constitute a take-out port (opening OP) for the sheet S ( Figure 1 , Fig.10 ). Therefore, it is possible to take out the sheet S from the top surface 11 of the packaging bag 10.

[0116] It should be noted that, in the present embodiment, although the splitting incision line 30 (eyelet M) is formed along the MD direction of the substrate BS and the CD direction of the sheet S, and the static friction coefficient is measured in the direction orthogonal to the direction in which the eyelet M extends (the CD direction of the substrate BS and the MD direction of the sheet S), there is no limitation on the direction of the sheet S and the substrate BS used to measure the static friction coefficient. For example, the splitting incision line 30 (eyelet M) may be formed along the CD direction of the substrate BS and the MD direction of the sheet S, and the static friction coefficient may be measured in the direction orthogonal to the direction in which the eyelet M extends (the MD direction of the substrate BS and the CD direction of the sheet S).

[0117] In addition, in the present embodiment, as described above, the case where the sheet S is contained in the packaging bag 10 in such a manner that the MD direction of the sheet S is along the CD direction of the base material BS is described, but the relationship between the MD direction of the sheet S and the CD direction of the base material BS is not limited. That is, there is no limitation on the direction in which the sheet S is contained in the packaging bag 10. For example, the sheet S may be contained in the packaging bag 10 in such a manner that the MD direction of the sheet S is along the MD direction of the base material BS.

[0118] The sheet package 100 of this embodiment can use the packaging bag 10 described above. Specifically, the sheet package 100 includes a packaging bag (the packaging bag of the first embodiment) 10 and a sheet S ( Figure 1 , Figure 2 ).

[0119] The sheet package 100 of the present embodiment is configured as a sheet package in which the sheet S is contained in the packaging bag 10 described above, so that the same effect as the packaging bag 10 described above can be obtained. That is, in the sheet package 100 of the present embodiment, even when the packaging bag 10 constituting the sheet package 100 is made of paper, the perforations M provided on the paper packaging bag 10 are easily torn, and even the paper packaging bag is easy to open ( Figure 1 , Fig.10 ).

[0120] In the packaging bag 10 of the present embodiment, as described above, the inner layer (resin layer) 10B containing a thermoplastic resin is provided on one surface of the base layer (paper layer) 10A containing a paper component, so that the texture of the packaging bag 10 becomes soft. As a result, the stiffness of the packaging bag 10 is suppressed, and the packaging bag 10 can be given a followability. Therefore, even when the material of the packaging bag is changed from resin to paper, it is possible to provide a packaging bag 10 that is not easily broken during manufacturing or transportation.

[0121] In the present embodiment, since the packaging bag 10 having conformability provided by laminating the inner layer (resin layer) 10B on the base layer (paper layer) 10A is provided with the cleavage line 30 , cleavage of the cleavage line 30 is easily achieved.

[0122] In addition, in the present embodiment, since the inner layer (resin layer) 10B provided on one surface of the base layer (paper layer) 10A contains a thermoplastic resin, when the packaging bag 10 is sealed (or closed), the inner layer (resin layer) 10B is heated, so that the melted inner layer (resin layer) 10B can act as an adhesive (have an adhesive function), thereby facilitating the sealing of the packaging bag 10.

[0123] In addition, in this embodiment, since the ratio of the paper component in the packaging bag 10 is 50% or more, the amount of paper in the packaging bag 10 is larger than the amount of resin, so the packaging bag 10 as paper can be recycled. In addition, since the amount of plastic used is reduced, the environmental load can be suppressed.

[0124] In this embodiment, as described above, by setting the thickness of the inner layer (resin layer) 10B to be 5 μm or more and 40 μm or less, it is easy to maintain the ratio of the paper component in the packaging bag to be 50% or more. In addition, the stiffness of the packaging bag can be suppressed while maintaining the adhesive function of the inner layer (resin layer) 10B when the packaging bag is sealed.

[0125] In this embodiment, as described above, by using low-density polyethylene as the thermoplastic resin contained in the inner layer (resin layer) 10B, the stiffness of the packaging bag 10 can be further suppressed and the adhesive function of the inner layer (resin layer) 10B when sealing the packaging bag 10 can be improved.

[0126] In this embodiment, as described above, when the packaging bag 10 is a pillow-type packaging bag and the inner layer (resin layer) 10B is arranged inside the packaging bag 10, the resin layers 10B can be bonded to each other by heat-melting at least one sealing portion. Thus, since the bonding function of the inner layer (resin layer) 10B can be effectively utilized, a packaging bag 10 with high sealing performance can be obtained.

[0127] Example

[0128] The present invention will be described in more detail below using examples. Examples and comparative examples were evaluated by the following tests.

[0129] [Test subject]

[0130] As a test body, a sheet package 100 (sheet package 100) in which a plurality of sheets S (sheet stack 20) ​​are packaged in a pillow-shaped package in a paper packaging bag 10 was prepared. Figures 1 to 8 ).

[0131] The packaging bag 10 is composed of a base material BS, and the base material BS is composed of a base layer 10A, an inner layer 10B, and an outer layer 10C ( Fig. 9 ). The material of the inner layer 10B is low-density polyethylene (PE). The outer layer 10C is a printed layer obtained by gravure printing. On the top surface 11 of the packaging bag 10, a cleavage cut line 30 (perforation M) is formed extending from the sealing portion 40 through the top surface 11 to the sealing portion 50 in the longitudinal direction (MD direction) of the packaging bag 10. In the embodiment and the comparative example, the ratio of the connecting portion T to the cutting portion C of the perforation M is 1:2.

[0132] The sheet stack 20 of the sheet material S uses tissue paper 1 (trade name "Elleair tissue paper double layer (medium size)", manufactured by Daio Paper Co., Ltd., double layer (2 layers), 200 sets (400 sheets), height H1: 70 mm, length L1: 210 mm, width (depth) W1: 115 mm, basis weight 23 g / m 2, density 0.293g / cm 3 ), tissue 2 (product name "Hervale tissue Eco-Dry (medium size)", manufactured by Daio Paper Co., Ltd., single layer (1 layer), 200 sheets, height H1: 67 mm, length L1: 210 mm, width (depth) W1: 115 mm, basis weight 33 g / m 2 , density 0.194g / cm 3 ), and toilet paper (trade name "Elleair i:na toilet paper soft package", manufactured by Daio Paper Co., Ltd., double layer (2 layers), 150 sets (300 sheets), height H1: 43mm, length L1: 181mm, width (depth) W1: 103mm, basis weight 10.7g / m 2 , density 0.171g / cm 3 ).

[0133] [Weight per square meter]

[0134] According to JIS P 8124 (2011), the weight per square meter (basis weight) of the base material (all layers) BS and the base layer 10A of the packaging bag 10 in the test body (sheet packaging body 100) is measured. The unit of weight per square meter is g / m 2 .

[0135] [Paper thickness]

[0136] The paper thickness (thickness) of the substrate (all layers) BS and the base layer 10A of the packaging bag 10 in the test body (sheet packaging body 100) was measured using an ISO paper thickness meter (CITIZEN, MEI-11) in accordance with JIS P 8118 (2014). The unit of thickness is μm.

[0137] [Tensile strength]

[0138] The tensile strength (mN) of the base material (all layers) BS and the base layer 10A of the packaging bag 10 in the test body (sheet packaging body 100) in the longitudinal direction (MD direction) and the transverse direction (CD direction) was measured using a Tensilon universal testing machine (RTG-1210 manufactured by A&D Co., Ltd.) in accordance with JIS P 8113 (2006).

[0139] [Elongation]

[0140] For the base material (all layers) BS and the base layer 10A of the packaging bag 10 in the test body (sheet packaging body 100), the elongation (%) in the longitudinal direction (MD direction) and the transverse direction (CD direction) was measured using a Tensilon universal testing machine (RTG-1210 manufactured by A&D Co., Ltd.) in accordance with JIS P 8113 (2006).

[0141] [Tear strength]

[0142] For the base material (all layers) BS and the base layer 10A of the packaging bag 10 in the test body (sheet packaging body 100), the tear strength in the longitudinal direction (MD direction) and the transverse direction (CD direction) of the fiber was measured using a tear strength tester (Elmendorf tear strength tester (digital display type) manufactured by Kumagai Riki Kogyo Co., Ltd.) in accordance with the provisions of JIS P 8116 (2000).

[0143] [Taber stiffness]

[0144] The Taber rigidity of the base material (all layers) BS of the packaging bag 10 in the test body (sheet packaging body 100) was measured in accordance with JIS P 8125 (2000). A Taber rigidity tester (manufactured by Toyo Seiki Seisaku-sho, Ltd.) was used for the measurement of the Taber rigidity.

[0145] [Static friction coefficient]

[0146] The static friction coefficient was measured in accordance with the horizontal method of JIS P 8147 (2010). A dynamometer tensile tester (AGS-500B manufactured by Shimadzu Corporation) was used for the measurement of the static friction coefficient.

[0147] Specifically, the static friction coefficient A1 between the inner surface IS (inner layer 10B) of the base material BS of the packaging bag 10 in the CD direction and the sheet S in the MD direction, and the static friction coefficient A2 between the inner surface IS (inner layer 10B) of the base material BS in the CD direction and the sheet S in the MD direction are measured.

[0148] It should be noted that the sheet S has a basis weight of 33 g / m 2 tissue paper (product name "Hervale tissue paper Eco-Dry single layer (medium size)", manufactured by Daio Paper Mfg. Co., Ltd., 200 sheets, height H1: 65 mm, length L1: 210 mm, width (depth) W1: 115 mm).

[0149] In addition, the static friction coefficient B1 between the CD direction of the outer surface OS (outer layer 10C) of the base material BS of the packaging bag 10 and the MD direction of the sheet S, and the static friction coefficient B2 between the CD direction of the outer surface OS (outer layer 10C) of the base material BS of the packaging bag 10 and the glossy surface of the aluminum foil (also called aluminum foil paper) were measured.

[0150] In addition, the aluminum foil used had a size of 30 cm in width, 7 m in length, and 20 μm in thickness (manufactured by UACJ Foil Co., Ltd., My Foil (registered trademark)).

[0151] In the measurement of static friction coefficients A1, A2, B1, and B2, the substrate BS is fixed on the horizontal plate side of the friction tester in such a way that the CD direction of the inner surface of the substrate BS (inner layer 10B) becomes the surface side, and the sheet S is fixed on the weight side of the friction tester in such a way that the MD direction of the surface of the sheet S becomes the surface side.

[0152] In addition, the ratio of the static friction coefficient A1 to the static friction coefficient B1 and the ratio of the static friction coefficient A2 to the static friction coefficient B2 were calculated.

[0153] [Ease of opening of the eyelet]

[0154] The ease of opening of the perforations M (tear cut lines 30) formed on the top surface 11 of the packaging bag 10 in the test body (sheet packaging body 100) was confirmed. The test was conducted for the case where a single-layer type sheet S (paper web) was contained in the packaging bag 10 and the case where a double-layer type tissue sheet was contained in the packaging bag 10. In the evaluation of the ease of opening of the perforations on the sheet package 100, when 10 users pressed the surface (top surface 11) on which the perforations M were formed on the packaging bag 10 with the thumbs of both hands and moved the thumbs in a separated manner in the CD direction of the substrate BS, the evaluation was 5 (excellent) when 0 to 2 people answered that it was difficult to open the package, 4 (good) when 3 to 4 people answered that it was difficult to open the package, 3 (pass) when 5 to 6 people answered that it was difficult to open the package, 2 (poor) when 7 to 8 people answered that it was difficult to open the package, and 1 (poor) when 9 to 10 people answered that it was difficult to open the package. The evaluation criteria are as follows.

[0155] 5: Very easy to open

[0156] 4: Easy to open

[0157] 3: Can be opened

[0158] 2: It can be opened but it is difficult to open

[0159] 1: Unable to open

[0160] Examples and comparative examples are described below.

[0161] [Example 1]

[0162] The inner layer 10B of the base material BS of the packaging bag 10 uses PE added with a lubricant, and the outer layer 10C is coated with an anti-slip agent (primer). The static friction coefficient A1 is 0.44, the static friction coefficient A2 is 0.31, the static friction coefficient B1 is 0.56, the static friction coefficient B2 is 0.42, the ratio of the static friction coefficient A1 to the static friction coefficient B1 is 0.786, and the ratio of the static friction coefficient A2 to the static friction coefficient B2 is 0.738. The conditions of the packaging bag 10, the conditions of the sheet (paper web), and the evaluation results are shown in Table 1.

[0163] [Example 2]

[0164] A test piece was prepared and evaluated in the same manner as in Example 1 except that the static friction coefficient A1 was 0.45, the static friction coefficient A2 was 0.44, the static friction coefficient B1 was 0.56, the static friction coefficient B2 was 0.51, the ratio of the static friction coefficient A1 to the static friction coefficient B1 was 0.804, and the ratio of the static friction coefficient A2 to the static friction coefficient B2 was 0.863. The conditions of the packaging bag 10, the conditions of the sheet (paper web), and the evaluation results are shown in Table 1.

[0165] [Example 3]

[0166] A test piece was prepared and evaluated in the same manner as in Example 1 except that the friction coefficient A1 was 0.38, the static friction coefficient A2 was 0.31, the static friction coefficient B1 was 0.55, the static friction coefficient B2 was 0.51, the ratio of the static friction coefficient A1 to the static friction coefficient B1 was 0.691, and the ratio of the static friction coefficient A2 to the static friction coefficient B2 was 0.608. The conditions of the packaging bag 10, the conditions of the sheet (paper web), and the evaluation results are shown in Table 1.

[0167] [Comparative Example 1]

[0168] A test piece was prepared and evaluated in the same manner as in Example 1 except that the friction coefficient A1 was 0.53, the static friction coefficient A2 was 0.47, the static friction coefficient B1 was 0.51, the static friction coefficient B2 was 0.50, the ratio of the static friction coefficient A1 to the static friction coefficient B1 was 1.039, and the ratio of the static friction coefficient A2 to the static friction coefficient B2 was 0.940. The conditions of the packaging bag 10, the conditions of the sheet (paper web), and the evaluation results are shown in Table 1.

[0169] [Table 1]

[0170]

[0171] As shown in Table 1, the density of the sheet laminate is 0.171 to 0.293 g / cm 3Below, in the test bodies with static friction coefficient A1 of 0.38-0.45, static friction coefficient A2 of 0.31-0.44, static friction coefficient B1 of 0.55-0.56, static friction coefficient B2 of 0.42-0.51, ratio of static friction coefficient A1 to static friction coefficient B1 of 0.691-0.804, and ratio of static friction coefficient A2 to static friction coefficient B2 of 0.608-0.863, the hole opening is good (Examples 1-3).

[0172] In contrast, in the test body with a friction coefficient A1 of 0.53, a static friction coefficient A2 of 0.47, a static friction coefficient B1 of 0.51, a static friction coefficient B2 of 0.50, a ratio of the static friction coefficient A1 to the static friction coefficient B1 of 1.039, and a ratio of the static friction coefficient A2 to the static friction coefficient B2 of 0.940, the hole opening ease was poor (Comparison Example 1).

[0173] Although the embodiment of the present invention has been described above, the present invention is not limited to the specific embodiment, and various modifications and changes can be made within the scope of the invention described in the claims.

[0174] Preferred aspects of the present invention are described below.

[0175] In a first aspect of the present invention, there is provided a packaging bag for accommodating a sheet stack formed by stacking a plurality of sheets, wherein the density of the sheet stack is 0.09 g / cm 3 Above and 0.50g / cm 3 Below, the packaging bag is composed of a substrate containing a paper component, the first static friction coefficient of the inner surface of the substrate arranged on the inner side of the packaging bag is greater than 0.25 and less than 0.5, the second static friction coefficient of the outer surface of the substrate arranged on the outer side of the packaging bag is greater than 0.3 and less than 0.65, and the ratio of the first static friction coefficient to the second static friction coefficient is greater than 0.5 and less than 0.9.

[0176] In this specification, the paper component is a component formed by gluing plant fibers. The density of the sheet laminate is the density measured in accordance with the provisions of JIS P 8118 (2014). The static friction coefficient represents the ratio of the friction force generated on the contact surface of two objects in a state of no relative motion to the force acting on the contact surface at right angles.

[0177] The outside of the packaging bag refers to the side of the packaging bag substrate that is not in contact with the sheet material contained in the packaging bag (i.e., the side opposite to the side where the sheet material is contained in the packaging bag or the side where the outer layer of the substrate is formed). The inside of the packaging bag refers to the side of the packaging bag substrate that is in contact with the sheet material contained in the packaging bag (i.e., the side where the sheet material is contained in the packaging bag or the side where the inner layer of the substrate is formed).

[0178] In the first scheme, for a density of 0.09 g / cm 3 Above and 0.50g / cm 3 In the following sheet laminate, the first static friction coefficient of the inner surface of the substrate is 0.25 or more and 0.5 or less, the second static friction coefficient of the outer surface of the substrate is 0.3 or more and 0.65 or less, and the ratio of the first static friction coefficient to the second static friction coefficient is 0.5 or more and 0.9 or less. Thus, a certain friction force is generated on the inner surface of the substrate constituting the packaging bag, and a friction force greater than the friction force generated on the inner surface of the substrate is generated on the outer surface of the substrate.

[0179] Therefore, the friction force generated on the inner surface of the substrate becomes relatively smaller on the inner surface of the substrate and relatively larger on the outer surface of the substrate, based on the same sheet stack. In such a structure, since the finger of a person touching the substrate (hereinafter referred to as the finger) becomes less likely to slide relative to the substrate, and on the other hand, the substrate becomes easier to slide relative to the sheet stack (sheet), if a perforation is provided on a paper packaging bag, the perforation is easy to tear, and even a paper packaging bag becomes easy to open.

[0180] In a second aspect of the present invention, there is provided a packaging bag according to the first aspect, wherein the substrate comprises a base layer containing the paper component; and an inner layer laminated on one surface of the base layer and arranged inside the packaging bag, the inner layer comprising a thermoplastic resin, the thermoplastic resin containing a slip agent. In this specification, the slip agent is an additive that reduces the friction coefficient.

[0181] In the second embodiment, since the base material of the packaging bag includes a base layer including a paper component, and an inner layer laminated on one surface of the base layer and arranged on the inner side of the packaging bag, the inner layer includes a thermoplastic resin containing a lubricant, and thus the static friction coefficient between the inner surface of the base material and the sheet stack can be reduced. As a result, since the inner surface of the base material becomes easy to slide relative to the sheet material, when a perforation is provided on the paper packaging bag, the perforation is easy to tear, and even a paper packaging bag becomes easy to open.

[0182] In a third aspect of the present invention, there is provided a packaging bag according to the first or second aspect, wherein the substrate comprises a base layer containing the paper component; and an outer layer laminated on the other side of the base layer and arranged on the outside of the packaging bag, the outer layer containing an anti-slip agent. In this specification, the anti-slip agent is an additive that increases the friction coefficient.

[0183] In the third embodiment, since the base material of the packaging bag includes a base layer including a paper component and an outer layer, which is laminated on the other surface of the base layer and arranged on the outside of the packaging bag, and the outer layer contains an anti-slip agent, it is possible to increase the friction generated between the outer layer of the base material and the finger touching the outer layer of the base material. As a result, since the finger touching the base material becomes less likely to slide relative to the base material, if a perforation is provided on the paper packaging bag, the perforation is easily torn, and even a paper packaging bag is easy to open.

[0184] In a fourth aspect of the present invention, there is provided a packaging bag according to any one of the first to third aspects, wherein the first static friction coefficient and the second static friction coefficient are static friction coefficients between a CD direction of the substrate and an MD direction of the sheet.

[0185] In the fourth embodiment, the static friction coefficient between the inner surface of the substrate in the CD direction and the MD direction of the sheet is used as the first static friction coefficient, so that the inner surface of the substrate in the CD direction becomes easy to slide relative to the MD direction of the sheet. The static friction coefficient between the outer surface of the substrate in the CD direction and the MD direction of the sheet is used as the second static friction coefficient, so that the outer surface of the substrate in the CD direction becomes difficult to slide relative to the finger touching the substrate.

[0186] Thus, when the sheet is placed in the packaging bag so that the MD direction of the sheet is along the CD direction of the base material and holes are formed in the MD direction of the base material, the holes are torn apart when the thumbs of both hands are pressed on the surface of the packaging bag where the holes are formed and the thumbs are moved in a separated manner in the CD direction of the base material. At this time, the holes are easily torn apart with a small force, so that the packaging bag is opened more easily.

[0187] In a fifth aspect of the present invention, there is provided a packaging bag according to any one of the first to fourth aspects, wherein a tearing cut line is formed on the top surface of the packaging bag along the MD direction of the substrate. In this specification, the tearing cut line is a cut line (e.g., a perforation) in which cut portions and connecting portions (uncut portions between two cut portions) are alternately arranged and two adjacent cut portions become continuous cut portions when the connecting portion is broken.

[0188] In the fifth embodiment, a tearing cut line is formed on the top surface of the packaging bag along the MD direction of the substrate, so that the tearing cut line can be torn by simply pressing the top surface of the packaging bag with the thumbs of both hands and moving the thumbs in a separated manner in the CD direction of the substrate, thereby making it easy to open the packaging bag. In addition, the torn tearing cut line can constitute a take-out port for the sheet material formed on the top surface of the packaging bag.

[0189] According to a sixth aspect of the present invention, there is provided a sheet material package, comprising: the packaging bag according to any one of the first to fifth aspects; and a sheet material contained in the packaging bag. In the sixth aspect, by constituting a sheet material package in which a sheet material is contained in the packaging bag, the same effects as those of the packaging bag described above can be obtained. That is, according to the sixth aspect, there can be provided a sheet material package, which can be easily opened even when the packaging bag constituting the sheet material package is made of paper.

[0190] This application claims priority based on Japanese patent application No. 2022-056679 filed on March 30, 2022, and incorporates its entire contents herein.

[0191] Explanation of symbols

[0192] 100 sheets packaging

[0193] 10 packing bags

[0194] BS substrate

[0195] IS inner surface

[0196] OS outside

[0197] 10A base layer (paper layer)

[0198] 10B inner layer (resin layer)

[0199] 10C outer layer (printing layer)

[0200] 11 Top

[0201] 12 Bottom

[0202] 13, 14 side

[0203] 15, 16 short side

[0204] 20 sheets laminate

[0205] S Sheet

[0206] 30 Split with incision line

[0207] M eyelet

[0208] OP outlet (opening)

[0209] 40, 50 sealing part (end sealing)

[0210] 60 Sealing part (bottom sealing)

[0211] L1, L2 length

[0212] W1, W2 width

[0213] H1, H2 heights.

Claims

1. A packaging bag for containing a sheet stack formed by stacking a plurality of sheets, The density of the sheet stack is 0.09 g / cm 3 Above and 0.50g / cm 3 the following, The packaging bag is composed of a substrate containing a paper component. The first static friction coefficient of the inner surface of the substrate disposed inside the packaging bag is 0.25 or more and 0.5 or less, The second static friction coefficient of the outer surface of the substrate arranged outside the packaging bag is 0.3 or more and 0.65 or less, A ratio of the first static friction coefficient to the second static friction coefficient is greater than or equal to 0.5 and less than or equal to 0.

9.

2. The packaging bag according to claim 1, wherein: The substrate comprises a substrate comprising the paper component; and an inner layer, laminated on one surface of the base layer and arranged on the inner side of the packaging bag, The inner layer comprises a thermoplastic resin, The thermoplastic resin contains a slip agent.

3. The packaging bag according to claim 1 or 2, wherein: The substrate comprises a substrate comprising the paper component; and an outer layer, which is laminated on the other side of the base layer and arranged on the outside of the packaging bag, The outer layer contains an anti-slip agent.

4. The packaging bag according to any one of claims 1 to 3, wherein: The first static friction coefficient and the second static friction coefficient are static friction coefficients between the CD direction of the substrate and the MD direction of the sheet.

5. The packaging bag according to any one of claims 1 to 4, wherein: A cleavage line is formed on the top surface of the packaging bag along the MD direction of the substrate.

6. A sheet material package, comprising: The packaging bag according to any one of claims 1 to 5; and The sheet is contained in the packaging bag.

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