JP7481827B2 - Packaging - Google Patents

Description

The present invention relates to a package, particularly a package suitable for packaging soft products such as paper products.

Conventionally, packages are known that contain rolled paper products such as toilet paper and kitchen paper, and layered paper products such as tissue paper and wipes as packaged items.

For example, Patent Document 1 discloses a package for wrapping rolled paper products, in which a gusset is folded symmetrically into a cylindrical film such as polyethylene to form a main body, and the top of the main body is folded flat to form a handle.

On the other hand, paper cartons made of high-weight paperboard are commonly used as packaging for layered paper products. As an alternative to paper cartons, for example, Patent Document 2 discloses a film packaging body in which a perforation is provided in the center of the top surface of a packaging bag made of a flexible resin film.

However, there has been a demand for new packaging materials that can be used to package soft products such as the paper products mentioned above. In particular, with the growing awareness of environmental issues in recent years, there is a desire to reduce the use of plastics (synthetic resins), and even in paper packaging materials, there is a desire to reduce the amount of packaging materials used, but this has been difficult to achieve when packaging soft products such as paper products.

JP 2004-269010 A JP 2016-188092 A

The present invention was made in consideration of these circumstances, and its purpose is to provide a new packaging body that is particularly suitable for packaging soft products such as paper products.

The inventors of the present invention have conducted intensive research in view of the above-mentioned problems. As a result, they have found that when a paper product, for example a soft product such as tissue paper, is packaged and a paper-based material is selected as the packaging base material, even if the paper-based packaging base material is inherently difficult to package soft products with, by setting the bending stiffness in the MD direction of the packaging base material within a specific numerical range, it is possible to practically package soft products well, thereby solving the above-mentioned problems, and have completed the present invention. Specifically, the present invention provides the following.

(1) A first aspect of the present invention is a packaging body for packaging one or more packaged items, comprising a packaging base material including at least a paper base material, and characterized in that the bending stiffness of the packaging base material in the MD direction is 20 μN·m or more and 330 μN·m or less.
(2) A second aspect of the present invention is the packaging body described in (1), characterized in that the ratio of the basis weight of the paper base material to the basis weight of the packaging base material is 51% or more and 100% or less.
(3) A third aspect of the present invention is the packaging body according to (1) or (2), characterized in that the basis weight of the packaging base material is 30 g/ ^m2 or more and 105 g/ ^m2 or less.
(4) A fourth aspect of the present invention is the packaging body according to any one of (1) to (3), characterized in that the packaging base material further comprises a heat seal layer.
(5) A fifth aspect of the present invention is the packaging body according to (4), characterized in that the heat seal layer contains a polyolefin resin.
(6) A sixth aspect of the present invention is the packaging body according to (4) or (5), characterized in that the paper base material has a basis weight of 25 g/ ^m2 or more and 85 g/ ^m2 or less, and the heat seal layer has a basis weight of 5 g/ ^m2 or more and 50 g/ ^m2 or less.
(7) A seventh aspect of the present invention is the packaging body according to any one of (1) to (6), characterized in that the packaging base material further comprises an adhesive layer.
(8) An eighth aspect of the present invention is a packaging body according to any one of (1) to (7), characterized in that the paper base material is produced using pulp having a softwood kraft pulp content of 50% by weight or more and 100% by weight or less.
(9) A ninth aspect of the present invention is a packaging body according to any one of (1) to (8), characterized in that the packaged item is tissue paper.
(10) A tenth aspect of the present invention is the packaging body described in (9), characterized in that the tissue paper is a laminated or rolled tissue paper.
(11) An eleventh aspect of the present invention is a packaging body according to any one of (1) to (10), characterized in that the packaging body is a caramel packaging body.

The present invention provides a novel package that is particularly suitable for packaging soft products such as paper products.

FIG. 1 is a schematic plan view showing an example of a manufacturing process for the packaging body of the present invention. FIG. 2 is a schematic plan view showing another example of the process for producing the package of the present invention.

The following describes in detail the form for carrying out the present invention (hereinafter, "embodiment") with reference to the drawings. However, these are presented for illustrative purposes and are not intended to limit the present invention.

1. Package The package of the present invention is a package for packaging one or more packaged items, and is provided with a packaging base material including at least a paper base material.

The package of the present invention preferably has an opening for removing the packaged item. In addition, this opening is preferably provided by forming a tear line, such as a perforation, in the packaging base material so that the opening can be opened by cutting the tear line when in use.

2. Packaging Substrate (1) Paper Substrate The packaging substrate has at least a paper substrate. When the paper substrate is formed into a package, printing may be applied to the outer surface side of the paper substrate. In addition, the paper substrate may be an overcoated paper that is overcoated to ensure waterproofing.

The paper base material is manufactured using wood pulp as the main raw material. The pulp used here may be any of the conventionally known pulps used alone or in any mixture ratio, such as softwood kraft pulp, hardwood kraft pulp, groundwood pulp, thermomechanical pulp, chemi-thermomechanical pulp, or recycled paper pulp used in newspapers, flyers, rough magazines, coated magazines, thermal recording paper, pressure-sensitive recording paper, imitation paper, colored wood-free paper, copy paper, computer output paper, or a mixture of these recycled paper.

In the paper base material of the packaging body of the present invention, the pulp used is preferably 50 to 100% by weight of softwood kraft pulp and 0 to 50% by weight of hardwood kraft pulp, more preferably 70 to 100% by weight of softwood kraft pulp and 0 to 30% by weight of hardwood kraft pulp, and even more preferably 90 to 100% by weight of softwood kraft pulp and 0 to 100% by weight of hardwood kraft pulp. Unbleached pulp is also preferred. By setting the proportion of softwood kraft pulp to 50% or more and 100% or less by weight, it becomes easier to adjust the bending stiffness of the packaging base material to the required range.

The pulp slurry may contain materials other than pulp fiber as secondary materials. In this packaging material, the pulp fiber content is generally preferably 70% by weight or more and 100% by weight or less, more preferably 80% by weight or more and 100% by weight or less, and even more preferably 90% by weight or more and 100% by weight or less.

The cooking and bleaching methods used in pulp production are not particularly limited.

In addition, various commonly used additives, such as wet strength agents, fillers, sizing agents, dry strength agents, retention agents, color pigments, etc., may be added to the paper base material in appropriate amounts as needed.

The wet strength improver can be selected from among those commonly used and known. For example, it is preferable to select from polyamide-polyamine resins, polyacrylamide resins, melamine resins, etc. The amount of wet strength improver (mass in bone dry state) is usually 0.01% by weight to 0.7% by weight, preferably 0.02% by weight to 0.5% by weight, more preferably 0.03% by weight to 0.3% by weight, based on the pulp (mass in bone dry state). If the amount of wet strength improver exceeds 0.7% by weight, it is difficult to obtain an effect commensurate with the amount, resulting in increased costs and reduced disintegration properties, which may make it difficult to reuse the packaging of the present invention later. If the amount of wet strength improver is less than 0.01% by weight, it is difficult to obtain sufficient wet strength, and the packaging may be easily torn when wet with water, resulting in poor functionality.

In the packaging body of the present invention, these raw materials can be made into paper using a normal papermaking process to obtain the paper base material for the packaging substrate.

The basis weight of the paper base material of the packaging substrate is preferably 25 g/m ² or more and 85 g/m ² or less, more preferably 32 g/m ² or more and 70 g/m ² or less, and even more preferably 40 g/m ² or more and 55 g/m ² or less. By having the basis weight of the paper base material within the above range, it becomes easier to achieve all of the required flexibility, softness, and strength of the packaging substrate while suppressing the amount of paper base material used.

The basis weight of the paper substrate can be determined, for example, as follows.
First, prepare a 0.1 M acetic acid solution and a 0.1 M sodium acetate solution. Mix about 830 g of the 0.1 M acetic acid solution and about 160 g of the 0.1 M sodium acetate solution to make the pH 4, and use this as an acetate buffer solution. Add Cellulase Onozuka P1500 (manufactured by Yakult Co., Ltd.) to this acetate buffer solution so that the amount added is 1 wt %.
50 ml of acetate buffer containing cellulase Onozuka P1500 and 0.5 g of packaging substrate (paper substrate with heat seal layer) are placed in a vial and tightly capped. After shaking for 24 hours at 180 rpm and 40°C, the heat seal layer is sampled from the vial and the mass of the heat seal layer is measured. The basis weight of the paper substrate is calculated from the mass of the packaging substrate (0.5 g) and the mass of the sampled heat seal layer according to the following formula.
Basis weight of paper base material =
Basis weight of packaging substrate × [(mass of packaging substrate − mass of heat seal layer) / mass of packaging substrate]

(2) Heat seal layer In the package of the present invention, the packaging base material is usually preferably provided with a heat seal layer. The heat seal layer may be formed on the entire surface of the paper base material, or may be formed only on a part of the surface, for example, on the part where the paper base materials are laminated and joined together. The position, size, and proportion of the heat seal layer on the surface of the paper base material can be appropriately set.

The material constituting the heat seal layer is not particularly limited, and any of various materials exhibiting heat sealability can be used, such as polyolefin resins and other thermoplastic resins. Among these, it is preferable to use polyolefin resins. Examples of such materials include low-density polyethylene, linear low-density polyethylene, high-density polyethylene, ethylene-α-olefin copolymers, ethylene-vinyl acetate copolymers, ethylene-acrylic acid copolymers, ethylene-ethyl acrylate copolymers, ethylene-methyl acrylate copolymers, ethylene-methacrylic acid copolymers, ionomers, amorphous polyesters, polypropylene, styrene-acrylic copolymers, propylene-ethylene copolymers (preferably copolymers with an ethylene content of 10 mol% or less), or polypropylene-based resins obtained by graft-polymerizing or copolymerizing unsaturated carboxylic acids, unsaturated carboxylic anhydrides, ester monomers, etc. with polypropylene, medium-density polyethylene, high-density polyethylene, etc. The materials constituting the heat seal layer may be used alone or in combination of two or more.

The heat seal layer can be formed by a commonly used method, for example, a method of forming a film of a thermoplastic resin such as a polyolefin resin or a composition containing a thermoplastic resin on a paper substrate by an extrusion method, a method of attaching a film made of a thermoplastic resin or containing a thermoplastic resin to a paper substrate using a known heat seal processing device (lamination processing device), a method of applying a water-based heat seal agent in which a thermoplastic resin or a thermoplastic resin composition is dissolved or dispersed in water, or a solvent-based heat seal agent in which a thermoplastic resin or a thermoplastic resin composition is dissolved or dispersed in a solvent, to the paper substrate by a known method such as roll coating, gravure roll coating, kiss coating, etc.

The basis weight of the heat seal layer is preferably 50 g/m ² or less, more preferably 5 g/m ² or more and 50 g/m ² or less, more preferably 5 g/m ² or more and 35 g/m ² or less, and even more preferably 10 g/m ² or more and 20 g/m ² or less. When the basis weight of the heat seal layer is within the above range, the required bending stiffness in the MD direction of the packaging base material can be achieved, and there is a tendency that the sealing property and heat seal strength of the package can be easily ensured.

As described above, the package of the present invention is preferably provided with a take-out opening for taking out the packaged item, and preferably the take-out opening is formed with a tear line such as a perforation, and the take-out opening can be opened by cutting along the tear line. The take-out opening is required to be easy to open and difficult to tear, but a package that packages a soft packaged item may be difficult to open or may tear depending on the force applied when opening the take-out opening. By setting the basis weight of the heat seal layer to a range of 3 g/m ² to 50 g/m ² , preferably 5 g/m ² to 35 g/m ² , and more preferably 10 g/m ² to 20 g/m ² , it is possible to achieve both ease of opening the take-out opening and difficulty of tearing.

The basis weight of the heat seal layer can be determined, for example, as follows.
First, prepare a 0.1 M acetic acid solution and a 0.1 M sodium acetate solution. Mix about 830 g of the 0.1 M acetic acid solution and about 160 g of the 0.1 M sodium acetate solution to make the pH 4, and use this as an acetate buffer solution. Add Cellulase Onozuka P1500 (manufactured by Yakult Co., Ltd.) to this acetate buffer solution so that the amount added is 1 wt %.
50 ml of acetate buffer containing cellulase Onozuka P1500 and 0.5 g of packaging substrate (paper substrate with heat seal layer) are placed in a vial and tightly capped. After shaking for 24 hours at 180 rpm and 40°C, the heat seal layer is sampled from the vial and the mass of the heat seal layer portion is measured. The basis weight of the heat seal layer is calculated from the mass (0.5 g) of the packaging substrate (paper substrate with heat seal layer) and the mass of the sampled heat seal layer according to the following formula.
Basis weight of heat seal layer =
Basis weight of packaging substrate × (mass of heat seal layer / mass of packaging substrate)

(3) Adhesive layer In the package of the present invention, the packaging substrate may be provided with an adhesive layer instead of or in addition to the heat seal layer. The packaging substrate of the present invention may have a layer structure such as paper substrate/adhesive layer, paper substrate/heat seal layer/adhesive layer, paper substrate/adhesive layer/heat seal layer, etc. The adhesive layer may also be formed on the entire surface of the paper substrate or the heat seal layer formed on the paper substrate, or may be formed only on a part of the surface, for example, the part where the paper substrates are laminated and joined together. The position, size, and proportion of the adhesive layer on the surface of the paper substrate can be appropriately set.

The adhesive constituting the adhesive layer is not particularly limited, and any known adhesive can be used, such as an ethylene-based adhesive, a two-component curing urethane-based adhesive, a polyester urethane-based adhesive, a polyether urethane-based adhesive, an acrylic-based adhesive, a styrene-acrylic-based adhesive, a polyester-based adhesive, a polyamide-based adhesive, a polyvinyl acetate-based adhesive, an epoxy-based adhesive, or a rubber-based adhesive. Among these, ethylene-based adhesives such as ethylene-vinyl acetate copolymer and ethylene-ethyl acrylate copolymer, which can be used as hot melt adhesives, are preferred.

The adhesive layer can be formed by applying the adhesive to the paper substrate or to a heat seal layer formed on the paper substrate by a known method such as roll coating, gravure roll coating, kiss coating, etc.

The basis weight of the adhesive layer (dry coating amount of adhesive) is usually preferably 2 g/ ^m2 or more and 30 g/ ^m2 or less, more preferably 3 g/ ^m2 or more and 25 g/ ^m2 or less, and even more preferably 5 g/ ^m2 or more and 20 g/ ^m2 or less.

As mentioned above, in the packaging substrate of the present invention, an adhesive layer may be provided instead of a heat seal layer, but a heat seal layer, particularly a heat seal layer containing a polyolefin resin, usually has better adhesiveness than an adhesive layer, and providing a heat seal layer, particularly a heat seal layer containing a polyolefin resin, may make it easier to package the packaged item.

(4) Other layers The packaging substrate of the present invention may have other layers in addition to the paper substrate, the heat seal layer and/or the adhesive layer. Examples of the other layers include a water vapor barrier layer, an oxygen barrier layer, a printing layer, a printability improving layer, an overprint layer, a light shielding layer, etc. These other layers can be provided, for example, between the paper substrate and the heat seal layer or the adhesive layer, or on the uppermost surface of the packaging substrate, and may be one layer or two or more layers.

(5) Physical properties, shape, etc. of the entire packaging substrate In the package of the present invention, the bending stiffness of the packaging substrate in the MD direction is 20 μN·m or more and 330 μN·m or less. Conventionally, there has been no package using a packaging substrate that contains such a paper substrate and has a specific bending stiffness in the MD direction, and by using this specific packaging substrate, it is possible to achieve all of the required flexibility, softness, and strength of the packaging substrate, and as a result, it has become possible to practically and satisfactorily package soft products (packaged items) such as paper products.
For example, when packaging a tissue paper laminate, the density of the tissue paper laminate is preferably 0.04 g/ ^cm3 or more and 0.30 g/ ^cm3 or less, more preferably 0.07 g/ ^cm3 or more and 0.25 g/ ^cm3 or less, and even more preferably 0.10 g/ ^cm3 or more and 0.20 g/ ^cm3 or less. Within this range, packaging becomes easier when the tissue paper laminate is packaged using the packaging base material of the present application. The density of the tissue paper laminate is measured as follows. First, the tissue paper laminate is taken from the package, and the mass of the tissue paper laminate is measured with an electronic balance after humidity control at 23°C and 50%. Then, the size (width, depth, height) of the tissue paper laminate is measured with a ruler, and the density is calculated by the following formula. Density of tissue paper laminate (g/ ^cm3 ) = Mass of tissue paper laminate (g) / (Width of tissue paper laminate (cm) x Depth of tissue paper laminate (cm) x Height of tissue paper laminate (cm))

The bending stiffness of the packaging substrate in the MD direction is preferably 30 μN·m or more and 225 μN·m or less, and more preferably 60 μN·m or more and 170 μN·m or less. The bending stiffness of the packaging substrate can be measured in accordance with ISO 2493. Note that bending stiffness is strongest when a load is applied in the longitudinal direction of the fibers, so when the fiber orientation ratio is close to 1.0, the bending stiffness in the MD direction tends to be smaller.

The thickness of the packaging substrate of the present invention is preferably 40 μm or more and 135 μm or less, more preferably 48 μm or more and 110 μm or less, and even more preferably 70 μm or more and 90 μm or less. The thickness of the packaging substrate can be measured in accordance with JIS P 8118:1998. The pressure condition of the pressurized surface was 100 kPa.

The density of the packaging substrate is preferably 0.6 g/cm ³ or more and 0.95 g/cm ³ or less, more preferably 0.65 g/cm ³ or more and 0.9 g/cm ³ or less, and even more preferably 0.7 g/cm ³ or more and 0.85 g/cm ³ or less. When the density of the packaging substrate is within the above range, the required strength, flexibility and softness of the packaging substrate are easily achieved, and the air permeability is easily maintained. The density of the packaging substrate can be measured and calculated in accordance with JIS P 8118:1998.

In addition, when packaging soft items, the length/height ratio along the MD direction of the packaging substrate of the shape of the packaged item may be set to a range of preferably 0.5 to 5, more preferably 1 to 4, and even more preferably 1.5 to 3, making it easier to package the packaged item.

The ratio of the basis weight of the paper base material to the basis weight of the packaging base material (e.g., the total basis weight of the paper base material and the heat seal layer and/or adhesive layer) may be 51% or more and 100% or less, but is usually more preferably 60% or more and 95% or less, and even more preferably 70% or more and 90% or less. By keeping it in the above range, it is possible to ensure ease of packaging for soft packaged items, and also to ensure good heat sealability or adhesion.

The basis weight of the packaging substrate (for example, the total basis weight of the paper substrate and the heat seal layer and/or adhesive layer) is preferably 30 g/m ² or more and 105 g/m ² or less, more preferably 37 g/m ² or more and 90 g/m ² or less, and even more preferably 50 g/m ² or more and 75 g/m ² or less. When the basis weight of the packaging substrate is within the above range, it becomes easier to achieve all of the required flexibility, softness, and strength of the packaging substrate. In addition, it becomes easier to adjust the bending stiffness of the packaging substrate to the above range.

As described above, in the packaging body of the present invention, the packaging substrate may have a heat seal layer and/or adhesive layer formed only on a portion of the surface of the paper substrate, and the layer structure may not be the same over the entire surface of the packaging substrate. In this case, the physical properties of the packaging substrate, the basis weight of the paper substrate, the basis weight of the heat seal layer, etc. are taken as the overall average value.

3. Packaged Item The packaging of the present invention is suitable for packaging paper products, particularly soft products such as tissue paper. Examples of tissue paper include, but are not limited to, rolled tissue paper such as toilet paper and kitchen paper, and laminated tissue paper such as tissue paper, wipers, wet tissue, and paper hand towels. Among these, the packaging of the present invention is particularly suitable for packaging laminated tissue paper.

4. Packaging Format Examples of the packaging format of the package according to the present invention include caramel packaging, pillow packaging, and gusset packaging.

Caramel packaging is a packaging format in which the product is wrapped around a packaging base material that extends in one direction of the product in a direction that crosses this direction, or the product is placed into one axial end of a packaging base material that has been previously formed into a cylindrical shape. Then, of the packaging base material that protrudes from both ends of the product, two opposing flap-shaped sides are folded together, and then another two opposing flap-shaped sides are similarly folded together, and these folded parts are sealed by heat sealing or the like. Caramel packaging is suitable for packaging 2 to 9 pieces, preferably 2 to 6 pieces, and more preferably 4 pieces of rolled tissue paper, or for packaging laminated tissue paper. This caramel packaging can be performed using known equipment.

Pillow packaging is a packaging format in which the packaging substrate is overlapped at both ends in the width direction with the inner faces facing each other so as to encase the packaged item placed on or under a sheet-like packaging substrate in a cylindrical shape, the overlapped portion is formed into a cylindrical shape by heat sealing or the like, the bottom portion or the mouth portion is sealed in a horizontal line by heat sealing or the like to match the length (height) of the bag, and the sealed portion is cut into individual bags. This pillow packaging can be performed using a known device.
There are two types of pillow packaging: vertical pillow packaging, in which the packaging base is fed vertically to wrap the packaged item while filling it from above, and horizontal pillow packaging, in which the packaging base is fed horizontally to wrap the packaged item. When packaging tissue paper, horizontal pillow packaging is preferred from the perspective of packaging speed and the shape of the tissue paper.

Gusset packaging is a packaging format in which the packaging substrate is overlapped at both ends in the width direction with the inner faces facing each other so as to encase the packaged item placed on or under the sheet-like packaging substrate in a cylindrical shape, and the overlapped parts are formed into a cylindrical shape by heat sealing or the like, and the bottom or mouth parts are woven in to match the length (height) of the bag and sealed in a horizontal line by heat sealing or the like, and the sealed parts are cut into individual bags. This gusset packaging can be performed using known equipment.

1 is a schematic plan view showing an example of the manufacturing process of the packaging body 1 of the present invention. As shown in FIG. 1, first, the packaging base material 1a is transported from the upstream of the conveying direction in the form of a continuous sheet. The packaged item 1b is placed on the packaging base material 1a, and when passing the position of the folding, sealing and cutting device 30, the leading end of the packaging base material 1a in the conveying direction (MD direction) is returned over the packaged item 1b, overlapped on the packaging base material 1a, and folded by the folding, sealing and cutting device 30 so that the top and bottom of the packaged item 1b are covered with the packaging base material 1a. Next, both end portions where the packaging base material 1a is overlapped are sealed by heat sealing or the like along the width direction (CD direction) perpendicular to the manufacturing line direction, and the overlapped portion of the packaging base material 1a is sealed by heat sealing or the like along the conveying direction (MD direction) and cut to form the packaging body 1. Sealing and cutting may be performed simultaneously or separately. For example, after the packaged item 1b is placed on the packaging base material 1a, the packaging base material 1a can be cut to a predetermined size, the packaged item 1b can be wrapped in the packaging base material 1a, and sealed by heat sealing or the like. Alternatively, before the packaged item 1b is placed on the packaging base material 1a, the packaging base material 1a can be cut to a predetermined size, and then the packaged item can be placed, wrapped, and sealed by heat sealing or the like. The above caramel packaging can adopt a format in which the packaged item is wrapped while being packaged from the MD direction.

2 is a schematic plan view showing another example of the manufacturing process of the packaging body 1 of the present invention. As shown in FIG. 2, first, the packaging base material 1a is transported from the upstream of the conveying direction in the form of a continuous sheet. The packaged item 1b is placed on the packaging base material 1a, and when passing the position of the folding device 10, the packaging base material 1a is folded from the width direction (CD direction) perpendicular to the conveying direction (MD direction) by the folding device 10. Next, when passing the position of the sealing and cutting device 20, both ends where the packaging base material 1a is overlapped are sealed with heat seal or the like along the conveying direction (MD direction), and the packaging base material 1a is overlapped along the width direction (CD direction) perpendicular to the manufacturing line direction, and the overlapped part of the packaging base material 1a is sealed with heat seal or the like and cut to form the packaging body 1. Sealing and cutting may be performed simultaneously or separately. Also, the packaged item 1b may be placed under the packaging base material 1a, and packaging may be performed in that state, that is, in a state where the up-down direction is reversed from that in FIG. 2. Also, before placing the packaged item 1b on the packaging base 1a, the packaging base 1a may be cut to a predetermined size, and then the packaged item may be placed, wrapped, and sealed by heat sealing or the like. The above-mentioned gusset packaging and pillow packaging correspond to the packaging format in which the packaged item is wrapped from the CD direction. The above-mentioned caramel packaging can also adopt a packaging format in which the packaged item is wrapped from the CD direction.

The packaging body of the present invention uses a packaging substrate having a specific bending stiffness in the MD direction, and is particularly suitable for use when, for example, the packaging substrate is transported in the form of a continuous sheet, the packaged item is placed on it, the packaged item is wrapped and wrapped in the transport direction (manufacturing line direction; MD direction), and the packaged item is cut to a predetermined dimension in the width direction (CD direction) perpendicular to the transport direction, i.e., when the wrapping direction is the MD direction of the packaging substrate. Note that the packaged item may be placed on the packaging substrate after being cut to a predetermined size, or the packaging substrate may be cut to a predetermined size after the packaged item is placed on it.

For the packaging of the present invention, it is preferable to select caramel packaging as the packaging format.

Although the present invention has been described above using embodiments, it goes without saying that the technical scope of the present invention is not limited to the scope described in the above embodiments and examples. It will be clear to those skilled in the art that various modifications and improvements can be made to the above embodiments. Furthermore, it is clear from the claims that forms incorporating such modifications or improvements can also be included in the technical scope of the present invention.

The present invention will be described in detail below with reference to examples. Note that the present invention is not limited to the examples shown below.

In the examples and comparative examples, the physical properties of the packaging substrates prepared were measured using the following methods.

(Basis weight of packaging substrate)
The basis weight of the packaging substrate (total basis weight of the paper substrate and the heat seal layer and/or adhesive layer) was measured in accordance with JIS P 8124.

(Basis weight of paper base material and basis weight of heat seal layer)
First, 0.1 M acetic acid aqueous solution and 0.1 M sodium acetate aqueous solution were prepared. Approximately 830 g of the 0.1 M acetic acid aqueous solution and approximately 160 g of the 0.1 M sodium acetate aqueous solution were mixed to a pH of 4, and this was used as an acetate buffer solution. Cellulase Onozuka P1500 (manufactured by Yakult Co., Ltd.) was added to this acetate buffer solution so that the amount added was 1 wt %.
50 ml of acetate buffer containing cellulase Onozuka P1500 and 0.5 g of packaging substrate (paper substrate with heat seal layer) were placed in a vial and tightly capped. After shaking for 24 hours at 180 rpm and 40°C, the heat seal layer was sampled from the vial and the mass of the heat seal layer was measured. The basis weight of the paper substrate and the basis weight of the heat seal layer were calculated from the mass (0.5 g) of the packaging substrate (paper substrate with heat seal layer) and the mass of the sampled heat seal layer according to the following formula.
Basis weight of paper base material =
Basis weight of packaging substrate × [(mass of packaging substrate − mass of heat seal layer) / mass of packaging substrate]
Basis weight of heat seal layer =
Basis weight of packaging substrate × (mass of heat seal layer / mass of packaging substrate)

(Basis weight of adhesive layer (amount of adhesive applied))
The basis weight of the adhesive layer was calculated according to the following formula from the basis weight of the packaging base material determined as above and the basis weight of the paper base material measured in accordance with JIS P 8124 before providing the adhesive layer.
Basis weight of adhesive layer = grammage of packaging substrate - grammage of paper substrate

(Thickness of packaging substrate)
The thickness of the packaging substrate was measured using an automatic elevating paper thickness gauge standard model TM-600 (manufactured by Kumagai Riki Kogyo Co., Ltd.) in accordance with JIS P 8118: 1998. The pressure condition of the pressing surface was 100 kPa.

(Density of packaging substrate)
The density of the packaging base material was measured and calculated in accordance with JIS P 8118:1998.

(Measurement of bending stiffness in MD direction of packaging substrate)
The bending stiffness of the packaging substrate in the MD direction was measured using an L&W bending tester (manufactured by Lorentzen & Wettre) in accordance with the method described in ISO 2493. The packaging substrate was a test piece with a width of 38 mm and a length of 100 mm, and the measured value when the bending angle was 15 degrees and the bending length (span of the sample table) was 10 mm was taken as the bending resistance (load), and the bending stiffness (μN·m) was calculated using the following formula.
Bending stiffness (μN·m) = 60 × bending resistance (mN) × bending length 10 (mm) ² ÷ (π × bending angle 15 (°) × sample width 38 (mm))
If it is not possible to obtain a test specimen with a length of 100 mm, the length of the test specimen may be shortened. The test specimen should not include the perforation of the opening for taking out the test specimen, but if it is necessary to include the perforation in order to ensure the size of the test specimen, the perforation may be included.

Example 1
(Packaging substrate)
A paper base material was prepared using 100% by weight of softwood unbleached kraft pulp (NUKP) as the pulp raw material. A polyethylene layer was then formed as a heat seal layer on the paper base material by extrusion to prepare a packaging base material. The basis weight of the prepared packaging base material, the basis weight of the paper base material, and the basis weight of the heat seal layer, as well as the thickness, density, and bending stiffness in the MD direction of the packaging base material were measured and the results are shown in Table 1.

(Tissue paper packaging)
Using the prepared packaging base material, a package was prepared with dimensions of 12 cm in the MD direction of the packaging base material, 16 cm in the CD direction of the packaging base material, and 4 cm in height. Then, 50 sets of 2-ply tissue paper were placed in this package as the packaged item, and the package was sealed with caramel packaging to obtain a tissue paper package. The packaged item was wrapped in the MD direction while being packaged.

(Evaluation of ease of packaging)
The ease of packaging (productivity) of the present packaging when producing tissue paper packaging was evaluated. The evaluation criteria were as follows. For the following evaluation items, A to C were considered to be favorable levels, and D and E were considered to be unacceptable levels.
A: It was very easy to package and had excellent productivity.
B: Easy to package and excellent productivity.
C: A slight decrease in productivity was observed, but it was not noticeable.
D: Productivity has decreased significantly.
E: The productivity was difficult to apply to actual operation.
The evaluation results are shown in Table 1.

(Example 2) to (Example 10) and (Comparative Example 1) to (Comparative Example 3)
A packaging substrate having the physical properties shown in Table 1 was prepared in the same manner as in Example 1, and a tissue paper package was prepared using this in the same manner as in Example 1, and its ease of packaging (productivity) was evaluated. However, in Example 2, instead of providing a polyethylene layer as a heat seal layer on the paper substrate, a styrene-acrylic adhesive layer (adhesive coating amount: 10 g/m ² ) was provided.

As is clear from the results shown in Table 1, the packages of Examples 1 to 10, in which the bending stiffness in the MD direction of the packaging substrate was 20 μN·m or more and 330 μN·m or less, were excellent in terms of ease of packaging soft items (tissue paper).

REFERENCE SIGNS LIST 1 Package 1a Packaging base material 1b Packaged item 10 Folding device 20 Sealing and cutting device 30 Folding and sealing and cutting device

Claims (1)

A pillow package for packaging one or more packaged items,
A packaging substrate including at least a paper substrate,
The packaging substrate does not have a heat seal layer and further comprises an adhesive layer;
The adhesive layer has a basis weight of 3 g/m2 ^or more and 25 g/m2 ^or less ,
The paper base material has a basis weight of 32 g/m ² or more and 70 g/m ² or less ,
The bending stiffness of the packaging substrate in the MD direction is 60 μN · m or more and 170 μN · m or less ,
The length/height ratio in the MD direction of the packaging substrate is 1.5 or more and 3 or less;
The basis weight of the packaging substrate is 37 g/m ² or more and 90 g/m ² or less,
The packaged item is a laminated thin paper that is a tissue paper laminate having a density of 0.07 g/cm3 ^or more and 0.25 g/cm3 ^or less,
A packaging body, characterized in that the paper base material is produced using pulp in which the proportion of softwood kraft pulp is 50% by weight or more and 100% by weight or less.

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