JP7187945B2 - Packaging material, packaging bag using the packaging material, and method for manufacturing the packaging material - Google Patents

Description

TECHNICAL FIELD The present invention relates to a packaging material, a packaging bag using the packaging material, and a method for manufacturing the packaging material.

In recent years, a large number of easy-open packaging bags have been commercialized. Such a packaging bag is easy to tear in any one direction (generally, one of the width direction and the direction perpendicular to the width direction), but has the property of being hard to tear in other directions.

As a packaging material for a packaging bag having easy-openability as described above, for example, as in Patent Document 1, a uniaxially oriented plastic film such as a uniaxially oriented polyester film and a uniaxially oriented polypropylene film is laminated with a sealant layer. A packaging material is proposed.

Moreover, from the viewpoint of design, there are cases in which packaging materials that make the most of the texture of paper are used (for example, Patent Literature 2). In packaging materials using paper as a base material, a uniaxially oriented plastic film is laminated as an intermediate base material between the paper base material and the sealant layer. By applying a uniaxially stretched plastic film, it is possible to impart the property of easily tearing in one direction to a paper-based packaging material. Therefore, it is possible to make the packaging bag easy to open while making the most of the texture of the paper.
A dry lamination method is employed as a method for laminating the paper base material, the intermediate base material, and the sealant layer. In the dry lamination method, it is common to apply a heat-resistant plastic film as an intermediate substrate and form an adhesive layer on the intermediate substrate.

JP 2017-222393 A JP 2008-265854 A

However, packaging materials using conventional paper substrates have a problem of increasing the number of processes and production costs due to the large number of layers.

An object of the present invention is to provide a packaging material having excellent tearability, a packaging material using the packaging material, and a method for producing the packaging material.

In order to realize easy-openability without using a uniaxially stretched plastic film, for example, a method of using a packaging material in which a low-density paper and a sealant layer are laminated via an adhesive layer is conceivable. However, since such a paper base material has large unevenness on the surface, when the paper base material and the sealant layer are adhered, a portion where the intermediate base material and the paper base material are not adhered (unbonded portion) is generated. Cheap. Due to the influence of the unbonded portion, the tearability of the packaging material is poor, and even when used for packaging bags, the opening performance is not necessarily good.

As a result of intensive research by the present inventors to solve the above-mentioned problems, the use of a paper base material that has a direction dependency in the surface of the paper base material, that is, a paper base material that has orientation in the fibers, enables uniaxial It has been found that a packaging material having directional tearability can be obtained even without a stretched plastic film. Then, the inventors found that a tearable packaging bag can be easily obtained by applying the packaging material, thereby solving the above problems.

In order to solve the above problems, the present invention provides the following [1] to [10].
[1] A packaging material in which a paper substrate, an adhesive layer in contact with the paper substrate, and a sealant layer are laminated in this order, wherein the tensile strength in the first direction of the packaging material is σ ₁ , when the tensile strength in the second direction orthogonal to the first direction is defined as σ ₂ , the packaging material satisfies the conditional expression (1), and the adhesion of the paper base material in the first direction When the arithmetic mean roughness of the surface of the adhesive layer side is defined as Ra ₁ and the arithmetic mean roughness of the surface of the adhesive layer side of the paper base in the second direction is defined as Ra ₂ , the paper base is A packaging material that satisfies conditional expression (2).
σ ₁ /σ ₂ ≧2.0 (1)
(Ra ₁ +Ra ₂ )/2≦3.0 μm (2)
[2] The packaging material according to [1], in which the adhesive layer and the sealant layer are in contact with each other.
[3] The method according to [1], wherein a gas barrier layer is provided between the adhesive layer and the sealant layer, the gas barrier layer and the sealant layer are in contact with each other, and the gas barrier layer and the adhesive layer are in contact with each other. packaging material.
[4] Ra ₃ is the arithmetic mean roughness of the surface of the paper base opposite to the adhesive layer in the first direction, and the surface of the paper base opposite to the adhesive layer in the second direction; The packaging material according to any one of [1] to [3], wherein the paper substrate satisfies the following conditional expressions (3) and (4) when the arithmetic mean roughness of Ra is defined as Ra ₄ .
Ra ₃ >Ra ₁ (3)
Ra ₄ >Ra ₂ (4)
[5] The packaging material according to any one of [1] to [4], wherein the paper substrate has a density of 0.67 g/cm ³ or less.
[6] Any one of [1] to [5], wherein the ratio B/A of the thickness B (μm) of the adhesive layer to the thickness A (μm) of the paper substrate satisfies the following conditional expression (5): 1. The packaging material according to item 1.
0.02≤B/A≤0.50 (5)
[7] The packaging material according to any one of [1] to [6], wherein the adhesive layer has a thickness of 1 μm or more and 15 μm or less.
[8] The packaging material according to any one of [1] to [7], wherein the paper substrate has an air permeability of 20 s/100 ml or less according to JIS P8117:2009.
[9] A packaging bag formed of the packaging material according to any one of [1] to [8], wherein the sealant layer is the inner layer.
[10] A method for manufacturing the packaging material according to any one of [1] to [8],
forming the adhesive layer on one surface of the sealant layer by either a non-solvent lamination method or a dry lamination method; and laminating the paper substrate on the surface of the sealant layer facing the adhesive layer. and bonding the adhesive layer and the paper substrate.

According to the present invention, even when a paper base material is used, a packaging material having excellent tearability can be obtained. By using the packaging material, an easily openable packaging bag can be obtained.

It is a schematic sectional view showing one embodiment of the packaging material of the present invention. FIG. 4 is a schematic cross-sectional view showing another embodiment of the packaging material of the present invention; 1 is a rear view showing one embodiment of a packaging bag of the present invention; FIG.

[Packaging material]
The present invention relates to a packaging material in which a paper substrate, an adhesive layer in contact with the paper substrate, and a sealant layer are laminated in this order, wherein the tensile strength of the packaging material in the first direction is When the tensile strength in the second direction orthogonal to the first direction is defined as σ ₁ and the tensile strength in the second direction orthogonal to the first direction is defined as σ ₂ , the packaging material satisfies the conditional expression (1), and the paper base material in the first direction When the arithmetic mean roughness of the adhesive layer side surface is defined as Ra ₁ and the arithmetic mean roughness of the adhesive layer side surface of the paper base in the second direction is defined as Ra ₂ , the paper base satisfies conditional expression (2).
σ ₁ /σ ₂ ≧2.0 (1)
(Ra ₁ +Ra ₂ )/2≦3.0 μm (2)

FIG. 1 is a schematic cross-sectional view showing one embodiment of the packaging material of the present invention.
The packaging material 100 has a paper substrate 110, an adhesive layer 120, and a sealant layer 130 laminated in this order. A pattern layer 140 may be formed on the surface of the paper substrate 110 opposite to the adhesive layer 120 .

Adhesive layer 120 contacts paper substrate 110 . Also, in the example of FIG. 1, adhesive layer 120 contacts sealant layer 130 .

FIG. 2 is a schematic cross-sectional view showing another embodiment of the packaging material of the present invention.
The packaging material 200 has a gas barrier layer 232 between the sealant layer 230 and the adhesive layer 220 . Adhesive layer 220 contacts paper substrate 210 . Gas barrier layer 232 contacts sealant layer 230 and adhesive layer 220 . The packaging material 200 may also have a pattern layer 240 formed on the surface of the paper substrate 210 opposite to the adhesive layer 220 .

Specifically, the packaging material of the present invention can be exemplified by the following laminated structures in order. In addition, "/" means the boundary of each layer.
(1) Picture layer/paper base layer/adhesive layer/sealant layer (2) Paper base layer/adhesive layer/sealant layer (3) Picture layer/paper base layer/adhesive layer/gas barrier layer/sealant Layer (4) paper base layer/adhesive layer/gas barrier layer/sealant layer

In the packaging material of the present invention, when the tensile strength in the first direction of the packaging material is defined as σ ₁ and the tensile strength in the second direction orthogonal to the first direction is defined as σ ₂ , conditional expression (1) are required to meet
σ ₁ /σ ₂ ≧2.0 (1)

The "first direction" and the "second direction" are determined by the orientation direction of the fibers of the paper base material when the paper base material contained in the packaging material is viewed from the plane. The first direction is the orientation direction of the fibers, and the second direction is the direction perpendicular to the orientation direction of the fibers of the paper substrate.

When the fibers of the paper substrate are oriented in one direction, the tensile strength in the orientation direction tends to be high and the tensile strength in the direction perpendicular to the orientation direction tends to be low. That is, as will be described later, the paper substrate has directional dependence of tensile strength. Conditional expression (1) indicates that the directional dependence of the tensile strength of the paper substrate itself also affects the tensile strength of the packaging material (laminate), and the packaging material of the present invention has directional dependence on the tensile strength. indicates that As will be described later, when a non-oriented film is applied to the sealant layer, the directional dependence of the tensile strength of the packaging material is greatly affected by the paper substrate.
In the packaging material of the present invention, the tensile strength σ1 in the _first direction is greater than the tensile strength σ2 in the _second direction. σ ₁ /σ ₂ (tensile strength ratio) is preferably 2.5 or more, more preferably 3.0 or more. Note that if σ ₁ /σ ₂ is too large, the handling of the packaging material tends to deteriorate. Therefore, σ ₁ /σ ₂ is preferably 10.0 or less, more preferably 8.0 or less.
The tensile strength is a tensile strength measured according to JIS K7127:1999.

If the fibers of the paper base material are oriented, the paper base material is easy to tear in the orientation direction of the fibers and difficult to tear in directions other than the orientation direction (for example, perpendicular to the orientation direction or diagonal direction). there is
In the case of conventional packaging materials using paper substrates, it has been thought necessary to laminate a uniaxially stretched plastic film between the paper substrate and the sealant layer in order to impart the property of being easy to tear in one direction. . On the other hand, the paper base material used in the present invention has directional dependence of tearability due to the orientation of the fibers. Therefore, the packaging material of the present invention has excellent tearability in a specific direction even without a uniaxially stretched plastic film. As a result, the number of uniaxially stretched films can be reduced, leading to a reduction in the number of manufacturing steps and production costs. Moreover, the effect of volume reduction of packaging can also be produced.

<Paper substrate>
The paper substrate used in the present invention has an arithmetic mean roughness Ra ₁ of the adhesive layer side surface in the first direction of the paper substrate, and an adhesive layer side surface in the second direction orthogonal to the first direction. is defined as Ra ₂ , the conditional expression (2) must be satisfied.
(Ra ₁ +Ra ₂ )/2≦3 μm (2)

The above Ra ₁ and Ra ₂ are the arithmetic mean roughness measured in accordance with JIS B0601:2001, with a cutoff value of 0.8 mm. As used herein, the cutoff value refers to the cutoff value (λc) for the roughness curve.

Conditional expression (2) is an index representing the smoothness of the surface of the paper substrate that is in contact with the adhesive layer. The paper substrate used in the present invention has directional dependence in surface roughness due to the orientation of the fibers. Therefore, smoothness is expressed as the average value of Ra ₁ and Ra ₂ ((Ra ₁ +Ra ₂ )/2). When the surface roughness of the paper substrate is large, when the adhesive layer to be described later is formed, portions where the paper substrate and the adhesive layer are not adhered tend to occur. If (Ra ₁ +Ra ₂ )/2 exceeds 3.0 μm, the region where the paper base material and the adhesive layer do not come into contact with each other increases, so that the ease of tearing of the paper base material is difficult to propagate to the sealant layer. , it becomes a tear-resistant packaging material. By satisfying the conditional expression (2), a packaging material with excellent tearability can be obtained.
(Ra ₁ +Ra ₂ )/2 is more preferably 2.5 μm or less. Also, (Ra ₁ +Ra ₂ )/2 is preferably 1.2 μm or more.

The paper substrate used in the present invention has a higher tensile strength in the first direction than in the second direction. The ratio of the tensile strength in the first direction to the tensile strength in the second direction is preferably 4.0 or more, more preferably 5.0 or more, and even more preferably 6.0 or more. . If the tensile strength ratio of the paper base material is too large, the paper base material tends to be easily torn during the manufacturing process of the packaging material, resulting in poor handleability. Therefore, the tensile strength ratio is preferably 10.0 or less, more preferably 8.0 or less.
The tensile strength is a tensile strength measured according to JIS P8113:2006.

For the paper substrate, the arithmetic mean roughness of the surface opposite to the adhesive layer in the first direction is Ra ₃ , and the arithmetic mean roughness of the surface opposite to the adhesive layer in the second direction is Ra ₄ . In addition, it is preferable that the paper substrate satisfy the following conditional expressions (3) and (4).
Ra ₃ >Ra ₁ (3)
Ra ₄ >Ra ₂ (4)

It is known that the two sides of a paper substrate have different surface roughnesses. Conditional expressions (3) and (4) mean that the surface of the paper substrate facing the adhesive layer is smoother than the surface opposite to the adhesive layer. By providing the adhesive layer on the smooth surface side of the paper substrate, the adhesion between the paper substrate and the adhesive layer can be enhanced.

The paper substrate preferably has a density of 0.67 g/cm ³ or less. The low density of the paper base means that there are many voids in the paper base. Therefore, by setting the density to 0.67 g/cm ³ or less, the paper base material itself is more easily torn, resulting in a packaging material with excellent tearability. In addition, an advantageous effect in terms of design can be obtained in that a bulky and excellent paper base material can be easily obtained. The density of the paper substrate is more preferably 0.65 g/cm ³ or less, still more preferably 0.63 g/cm ³ or less, and particularly preferably 0.60 g/cm ³ or less.
In addition, when the density is too low, the strength of the paper substrate tends to decrease. In addition, the unevenness of the surface of the paper substrate tends to increase, and the area of the portion not in contact with the adhesive layer tends to increase. Therefore, the density of the paper substrate is preferably 0.50 g/cm ³ or more, more preferably 0.53 g/cm ³ or more, and even more preferably 0.55 g/cm ³ or more.
The above density is the density measured according to JIS P8118:2014.

Further, the paper substrate preferably has a basis weight of 15 g/m ² or more and 30 g/m ² or less. By setting the basis weight to 15 g/m ² or more, it is possible to easily suppress a decrease in the strength of the paper substrate. Furthermore, an advantageous effect in terms of design can be obtained in that a bulky and excellent paper base material can be easily obtained. Also, by setting the basis weight to 30 g/m ² or less, the packaging material can be easily torn. The basis weight is more preferably 17 g/m ² or more and 27 g/m ² or less, and even more preferably 20 g/m ² or more and 25 g/m ² or less.
In addition, the said basis weight is the basis weight measured based on JIS P8124:2011.

The paper substrate preferably has an air permeability of 20 s/100 ml or less according to JIS P8117:2009. By setting the air permeability to 20 s/100 ml or less, it is possible to obtain an advantageous effect in terms of design that a paper base material having excellent texture can be easily obtained. The air permeability is more preferably 15 s/100 ml or less, even more preferably 10 s/100 ml or less.
In addition, if the air permeability is too low, the strength of the paper substrate tends to decrease. Therefore, the air permeability is preferably 3 s/100 ml or more, more preferably 5 s/100 ml or more.

<Adhesive layer>
An adhesive layer is formed in contact with the paper substrate.
Examples of adhesives include polyvinyl acetate adhesives, polyacrylate adhesives, cyanoacrylate adhesives, ethylene copolymer adhesives, cellulose adhesives, polyester adhesives, polyamide adhesives, and polyimide adhesives. Adhesives, amino resin adhesives such as urea resins and melamine resins, phenol resin adhesives, epoxy adhesives, polyurethane adhesives (for example, cured products of polyols and isocyanate compounds), reactive (meth) acrylics Acid-based adhesives, rubber-based adhesives such as chloroprene rubber, nitrile rubber and styrene-butadiene rubber, silicone-based adhesives, inorganic adhesives such as alkali metal silicate and low-melting glass, and the like. The adhesive may be one of the above, or may be a mixture of two or more.
It is preferable to use an adhesive having gas barrier properties as the adhesive because the gas barrier properties (oxygen barrier properties, water vapor barrier properties) of the packaging material can be further enhanced. Adhesives having gas barrier properties include adhesive compositions containing a polyester polyol, an isocyanate compound, and a plate-like inorganic compound. Specific examples of such adhesives include trade names "PASLIM" and "PASLIM VM" manufactured by DIC Corporation.

As will be described later, the adhesive layer can be formed by either a non-solvent lamination method (solvent-free lamination) or a dry lamination method. The adhesive layer is formed by directly applying the above adhesive to the sealant layer or the gas barrier layer formed on the sealant layer. In the present invention, the uniaxially oriented plastic film as an intermediate substrate can be eliminated and the paper substrate and the adhesive layer can be brought into contact.

As the thickness of the adhesive layer increases, the adhesive strength increases and the tearability can be easily improved. On the other hand, if the thickness of the adhesive layer is too thick relative to the thickness of the paper substrate, tearing of the paper substrate will be difficult to propagate to the sealant layer.
Therefore, it is preferable that the ratio B/A of the thickness B (μm) of the adhesive layer to the thickness A (μm) of the paper substrate satisfies the following conditional expression (5).
0.02≤B/A≤0.50 (5)
B/A is more preferably 0.025 or more and 0.40 or less.

<Sealant layer>
The sealant layer is located in the innermost layer when the packaging bag is formed, and the surface of the inner layer side of the packaging bag comes into contact with the items to be packaged and protects the items to be packaged. When the material to be packaged is liquid, the sealant layer preferably has permeation resistance to the liquid.
In addition, the sealant layer preferably has heat-sealability on the inner layer side in order to make the packaging material easy to shape into a packaging bag.

The thickness of the sealant layer is not particularly limited, and is appropriately set according to the use of the packaging material and the type and properties of the items to be packaged. Usually, it is preferably about 10 to 200 μm. When a packaging bag is formed from the packaging material, the thickness of the sealant layer is more preferably 15-150 μm, still more preferably 20-100 μm.

Materials constituting the sealant layer include, for example, low density PE (LDPE), linear low density PE (LLDPE), medium density PE (MDPE), high density PE (HDPE), ethylene-vinyl acetate copolymer, Polyolefin resins such as propylene homopolymers, ethylene-propylene block copolymers, ethylene-propylene random copolymers, etc. may be mentioned, and one or more of these resins may be used. The sealant layer may be composed of a single layer or multiple layers of two or more layers. The sealant layer is preferably an unstretched film. For example, the sealant layer is preferably unstretched propylene film (CPP).

<Gas barrier layer>
The gas barrier layer blocks permeation of oxygen, water vapor, and the like between the packaged item and the external environment of the packaging material. In addition, it may also have a light-shielding property that blocks the transmission of visible light, ultraviolet rays, and the like. The gas barrier layer may be composed of one layer, or may be composed of multiple layers of two or more layers.

The gas barrier layer can be composed of known materials. For example, a vapor deposition film or a coating film having gas barrier properties may be formed on the surface of the sealant layer. In the case of the packaging material of the present invention, a configuration in which a vapor-deposited film as a gas barrier layer is provided on the sealant layer is preferable.
In addition, from the viewpoint of improving the adhesiveness of the deposited film and the coating film, the sealant layer may be subjected to a surface treatment in advance. Examples of the surface treatment include corona discharge treatment, ozone treatment, low-temperature plasma treatment using oxygen gas, nitrogen gas, glow discharge treatment, oxidant treatment, application of an anchor coating agent, and the like.

The vapor deposition film can be formed of, for example, inorganic substances such as silicon, aluminum, magnesium, calcium, potassium, tin, sodium, boron, titanium, lead, zirconium, yttrium, or oxides thereof.
Examples of methods for forming a deposited film include physical vapor deposition (PVD) methods such as vacuum deposition, sputtering, and ion plating, and chemical vapor deposition (CVD) methods such as plasma chemical vapor deposition, thermal chemical vapor deposition, and photochemical vapor deposition. law, etc.

The film thickness of the deposited film varies depending on the film-forming material, the required gas barrier performance, etc., but it is generally preferably about 5 to 200 nm, more preferably 5 to 150 nm, still more preferably 10 to 100 nm. In the case of inorganic oxides such as silicon oxides and aluminum oxides, the thickness is preferably about 5 to 100 nm, more preferably 5 to 50 nm, still more preferably 10 to 30 nm.

As the coating film, for example, the general formula R ¹ _n M (OR ² ) _m (wherein R ¹ and R ² are organic groups having 1 to 8 carbon atoms, M is a metal atom, n is an integer of 0 or more) , m represents an integer of 1 or more, and n+m is the valence of M.), a polyvinyl alcohol resin and/or an ethylene-vinyl alcohol copolymer, and a sol- A coating solution obtained by polycondensation by a sol-gel method in the presence of a gel method catalyst, acid, water and an organic solvent is applied onto the sealant layer and heated at 50 to 300° C. for 0.05 to 60 minutes. A coating film can be formed by heat treatment.

Also, the coating film may be an ethylene-vinyl alcohol copolymer. A coating film can be formed by applying a coating solution in which an ethylene-vinyl alcohol copolymer is dissolved in a solvent onto the sealant layer and then evaporating the solvent.

Examples of the coating method include roll coating such as a gravure roll coater, spray coating, spin coating, dipping, brush coating, bar coating, and coating means such as an applicator. It is preferable that the dry film thickness of the coating film is about 0.01 to 30 μm, more preferably 0.05 to 20 μm, and still more preferably 0.1 to 10 μm by one or more coatings.

Alternatively, a metal foil such as an aluminum foil may be used as the gas barrier layer, and the metal foil and the sealant layer may be bonded together. The thickness of the metal foil is usually about 4-12 μm.
Also, the gas barrier layer may be an ethylene-vinyl alcohol copolymer film. In this case, the sealant layer can be provided with the gas barrier layer by co-extrusion of the gas barrier layer and the sealant layer.

<Pattern layer>
The packaging material may further have a pattern layer for the purpose of enhancing the design of the packaging material. The pattern layer is located on the outer layer side of the paper substrate when the packaging bag is formed.

The picture layer is a broad concept that includes, for example, characters (product names, product indications, quality indications, etc.), figures, photographs, symbols, designs, patterns, and the like. Further, the pattern layer may be solid printing.
The pattern layer can be formed, for example, by printing. The pattern layer may be a single layer as shown in FIGS. 1 and 2, or may be formed from two or more layers.

The ink used to form the pattern layer (ink for forming the pattern layer) is obtained by appropriately mixing a binder resin with a pigment, a coloring agent such as a dye, an extender pigment, a solvent, a stabilizer, a plasticizer, a catalyst, a curing agent, and the like. is used. As the pigment, in addition to general-purpose colored pigments, luster pigments such as pearl pigments and metal flakes may be used.
The binder resin is not particularly limited, and examples include acrylic resins, styrene resins, polyester resins, urethane resins, chlorinated polyolefin resins, vinyl chloride-vinyl acetate copolymer resins, polyvinyl butyral resins, and alkyd resins. , petroleum-based resins, ketone resins, epoxy-based resins, melamine-based resins, fluorine-based resins, silicone-based resins, cellulose derivatives, rubber-based resins, and the like. These resins can be used alone or in combination of two or more.

The pattern layer can be formed by preparing a pattern layer-forming ink containing each component constituting the pattern layer, applying the ink, and drying and curing as necessary. The pattern layer-forming ink is preferably solventless in order to suppress solvent odor.
Gravure printing, offset printing, and flexographic printing are preferable as means for applying the pattern layer, and gravure printing is more preferable.

Although the total thickness of the pattern layer is not particularly limited, it is generally preferably about 1 to 10 μm, more preferably 1.5 to 5 μm.

<Other layers>
The packaging material may have other layers such as a surface protective layer and an antistatic layer as long as the effects of the present invention are not impaired.

[Method for manufacturing packaging material]
In the present invention, the adhesive layer can be formed by either a non-solvent lamination method (solvent-free lamination) or a dry lamination method.
First, the above-described adhesive or a solution containing the above-described adhesive and a solvent is applied on the sealant layer to form an adhesive layer. When forming a gas barrier layer on the sealant layer, an adhesive layer is formed on the gas barrier layer. A known method can be used to apply the adhesive.
After that, a paper base material is laminated on the adhesive layer, and the adhesive layer and the paper base material layer are laminated to bond the adhesive layer and the paper base material. At this time, the smooth surface of the paper substrate (the surface having arithmetic mean roughness Ra ₁ and Ra ₂ ) is arranged on the adhesive layer side.
Since it can be applied directly to the sealant layer, it is possible to eliminate the need for a uniaxially stretched plastic film as an intermediate substrate. Therefore, the number of steps and production cost can be reduced, and the volume of packaging can be reduced.
In the present invention, it is particularly preferable to form the adhesive layer by a non-solvent lamination method. In the non-solvent lamination method, since the adhesive does not contain a solvent, the solvent in the adhesive is not dried at a high temperature, so shrinkage of the sealant layer can be suppressed. In addition, it becomes possible to solve the problem of odor due to residual solvent.

[Packaging bag]
The packaging bag of the present invention is formed from the packaging material of the present invention described above.
More specifically, the packaging bag of the present invention is formed by sealing at least part of the packaging material of the present invention described above. It is preferable that the seal part utilizes the heat-sealing property of the sealant layer.

The forms of packaging bags are pillow bags with back seals and top and bottom seals on a cylindrical body (joint palm bags), three-sided seal bags with three side seals, four side seal bags with four side seals, and bags. Standing pouches with a three-dimensionally secured bottom that can stand on their own, and gusseted pouches with both sides or the bottom folded into a V shape.

FIG. 3 is a rear view showing one embodiment of the packaging bag. The packaging bag 300 is a pillow bag.
The packaging bag (pillow bag) 300 is made, for example, by sealing the sealant layer of one rectangular sheet-like packaging material 100 (or 200). The outer layer of the packaging bag 300 is the paper base material 110 (and the pattern layer 140).
The sealing portion of the packaging bag 300 includes a lower sealing portion 310 , an upper sealing portion 320 and a back sealing portion 330 . The lower seal portion 310 and the upper seal portion 320 are positioned on the sides of the packaging bag 300 . In the case of the pillow bag of FIG. 3 , the lower seal portion 310 and the upper seal portion 320 are substantially parallel, and the back seal portion 330 is substantially perpendicular to the lower seal portion 310 and the upper seal portion 320 .

The first direction of the paper substrate (the orientation direction of the fibers of the paper substrate) substantially coincides with the direction in which the user tears the packaging bag 300 to open it (tear direction).
In the case of the pillow bag of FIG. 3, the arrangement direction of the lower seal portion 310 and the upper seal portion 320 (direction of arrow D in FIG. 3) substantially coincides with the first direction of the packaging material 100 (or 200). The user opens the packaging bag 300 from the upper seal portion 320 toward the lower seal portion 310 (or from the lower seal portion 310 to the upper seal portion 320).

It should be noted that the packaging bag 300 may have a cut portion such as a notch portion (not shown). It is preferable that the cut portion is provided at an arbitrary location of the seal portion. It is particularly preferable to have a notch extending in a direction substantially parallel to the first direction of the paper substrate at an arbitrary location of the upper seal portion or the lower seal portion. By having the said structure, it can become easy to open a packaging bag along a tearing direction (1st direction of a paper base material) from a slit part as a starting point.

The packaging bag shown in FIG. 3 is merely an example, and even in the case of the three-side-sealed bag, the four-sidedly-sealed bag, the standing pouch, the gusset bag, etc., the tearing direction substantially coincides with the first direction of the paper substrate.

EXAMPLES The present invention will be described in detail below with reference to examples, but the present invention is not limited by these examples.

1. Measurements and Evaluations Paper substrates, packaging materials, and packaging bags were subjected to the following measurements and evaluations. The atmosphere during the measurement was set at a temperature of 23° C.±5° C. and a humidity of 40 to 65%. Moreover, the sample was exposed to the above atmosphere for 30 minutes or more before starting the measurement.

1-1. Surface shape of paper substrate Regarding both sides of the paper substrate 1 and the glossy surface of the paper substrate 2, the arithmetic mean roughness Ra when the cutoff value (λc) in accordance with JIS B0601: 2001 is 0.8 mm It was measured. In the measurement of the paper base material 1, the orientation direction of the fibers on each surface (hereinafter sometimes simply referred to as the "orientation direction") and the direction perpendicular to the orientation direction (hereinafter sometimes simply referred to as the "perpendicular direction") ). In the measurement of the paper substrate 2, each surface was scanned in the longitudinal direction (MD direction) and transverse direction (TD direction). Measurement was performed using SE-340 (trade name) manufactured by Kosaka Laboratory Co., Ltd. under the following measurement conditions, and the average value of 10 measurement results was defined as "arithmetic mean roughness Ra".
For the paper base material 1, the average value of the arithmetic mean roughness in the orientation direction and in the orthogonal direction was calculated. Also, for the paper base material 2, the average value of the arithmetic mean roughness in the vertical direction and the horizontal direction was calculated. The results are shown in Tables 1 and 2.
[Stylus of surface roughness detector]
Trade name SE2555N manufactured by Kosaka Laboratory (tip curvature radius: 2 μm, apex angle: 90 degrees, material: diamond)
[Measurement conditions of surface roughness measuring instrument]
・Measurement length: 10 mm
・Measurement speed: 0.03mm/s
・Measurement range: ±32 μm
・λs: 0.25 μm
・Vertical magnification: 2000 times ・Horizontal magnification: 15.98 times

1-2. Tensile Strength of Paper Base Material Paper base material 1 was cut into a size of 15 mm long by 220 mm wide, and a sample B cut into a size of 220 mm long by 15 mm wide was prepared. made.
A sample C cut into a size of 15 mm long×220 mm wide and a sample D cut into a size of 220 mm long×15 mm wide were prepared from the paper base material 2 .
According to JIS P8113: 2006, using a single column type material testing machine STA-1150 manufactured by Orientec Co., Ltd., under the conditions of a test length of 180 mm and a tensile speed of 300 mm / min, the tensile strength of each sample A to D was measured. did. The average value of 10 measurement results was defined as "tensile strength".
For the paper substrate 1, the ratio of the tensile strength in the orientation direction to the tensile strength in the orthogonal direction (tensile strength ratio) was calculated. For the paper base material 2, the ratio of tensile strength in the machine direction to tensile strength in the transverse direction (tensile strength ratio) was calculated. The results are shown in Tables 1 and 2.

1-3. Tensile strength of packaging material Regarding the packaging material using the paper base material 1, sample E cut into a size of 15 mm long × 70 mm wide with the orientation direction of the fibers as horizontal, and cut into a size of 70 mm long × 15 mm wide A sample F was prepared.
The paper base material 2 was cut into a size of 15 mm long×70 mm wide, and a sample H was cut into a size of 70 mm long×15 mm wide.
According to JIS K7127: 1999, using a single column type material testing machine STA-1150 manufactured by Orientec Co., Ltd., the tensile strength of each sample E to H was measured under the conditions of a test length of 50 mm and a tensile speed of 300 mm / min. did. The average value of the five measurement results was defined as "tensile strength".
For the packaging material using the paper base material 1, the ratio of the tensile strength in the orientation direction to the tensile strength in the orthogonal direction (tensile strength ratio) was calculated. For the packaging material using the paper base material 2, the ratio of tensile strength in the longitudinal direction to tensile strength in the transverse direction (tensile strength ratio) was calculated. The results are shown in Tables 1 and 2. The measurement of the tensile strength of the packaging materials of Comparative Examples 1 to 3 was omitted because the adhesion was poor.

1-4. Easy Openability The packaging bags (pillow bags) obtained in Examples and Comparative Examples were opened from the notch portion. "A" indicates that it was easily torn linearly along the cut direction of the notch (hereinafter referred to as the opening direction), and "A" indicates that the tear direction was oblique and difficult to tear, and not easily torn. "C". Evaluation results are shown in Tables 1 and 2. Since the packaging materials of Comparative Examples 1 to 3 exhibited poor adhesion, packaging bags were not prepared and evaluation of easy-openability was omitted.

2. Paper Base Material As the paper base material 1, special paper having a density of 0.59 g/cm ³ , a basis weight of 23.1 g/m ² and an air permeability of 6.4 s/100 ml was used.
Plain paper having a density of 0.73 g/cm ³ , a basis weight of 23.5 g/m ² and an air permeability of 36.4 s/100 ml was used as the paper base material 2 .

3. Preparation of packaging material and packaging bag (pillow bag) (Example 1)
A packaging material used in Example 1 was produced by a non-solvent lamination method.
An adhesive containing a polyester resin and a polyurethane compound (adhesive for non-solvent lamination, labeled "for non-sol" in Tables 1 and 2 on a sealant layer (CPP, monolayer film of ethylene-propylene block copolymer, thickness 25 μm). described) was applied to form an adhesive layer having a thickness of 3 μm. Next, the adhesive layer and the glossy surface of the paper substrate 1 were laminated to prepare the packaging material of Example 1.
A pillow bag of Example 1 was produced by heat-sealing the sealant layer using the resulting packaging material, with the tearing direction aligned with the orientation direction of the paper substrate 1 (see FIG. 3). A notch in the longitudinal direction (the orientation direction of the paper substrate 1 coincides) was formed in the upper seal portion of the pillow bag of Example 1.

(Example 2)
A packaging material used in Example 1 was produced by a non-solvent lamination method.
Using a sealant layer (CPP, monolayer film of ethylene-propylene block copolymer, thickness 25 μm) on which a 50 nm-thick aluminum vapor deposition film is formed, the same adhesive as in Example 1 is applied on the aluminum vapor deposition film, and the thickness A 3 μm adhesive layer was formed. Next, the adhesive layer and the glossy surface of the paper base material 1 were laminated to prepare the packaging material of Example 2.
A pillow bag of Example 2 was produced by heat-sealing the sealant layer of the resulting packaging material with the tearing direction aligned with the orientation direction of the paper substrate 1 . A notch in the longitudinal direction (the orientation direction of the paper substrate 1 coincides) was formed in the upper seal portion of the pillow bag of Example 2.

(Example 3)
A packaging material used in Example 3 was produced by a dry lamination method.
On the sealant layer (CPP, monolayer film of ethylene-propylene block copolymer, thickness 25 μm) gas barrier adhesive (adhesive for dry lamination, manufactured by DIC Corporation, trade name "PASLIM", in Tables 1 and 2 described as “for dry use”) was applied to form an adhesive layer with a thickness of 3 μm. Next, the adhesive layer and the glossy surface of the paper base material 1 were laminated to prepare the packaging material of Example 3.
Using the resulting packaging material, the sealant layer was heat-sealed with the tearing direction aligned with the orientation direction of the paper substrate 1 to prepare a pillow bag of Example 3. A notch in the longitudinal direction (the orientation direction of the paper base material 1 coincides) was formed in the upper seal portion of the pillow bag of Example 3.

(Comparative example 1)
A packaging material of Comparative Example 1 was produced in the same steps as in Example 1, except that the adhesive layer and the rough surface of the paper substrate were laminated.

(Comparative example 2)
A packaging material of Comparative Example 2 was produced in the same process as in Example 2, except that the adhesive layer and the rough surface of the paper substrate were laminated.

(Comparative Example 3)
A packaging material of Comparative Example 3 was produced in the same process as in Example 3, except that the adhesive layer and the rough surface of the paper substrate were laminated.

(Comparative Example 4)
A packaging material used in Comparative Example 4 was produced by a non-solvent lamination method.
An adhesive (adhesive for non-solvent lamination) containing a polyester resin and a polyurethane compound is applied on the sealant layer (CPP, monolayer film of ethylene-propylene block copolymer, thickness 25 μm) to form an adhesive layer with a thickness of 3 μm. formed. Next, the adhesive layer and the glossy surface of the paper base material 2 were laminated to prepare a packaging material of Comparative Example 4.
A pillow bag of Comparative Example 4 was prepared by heat-sealing the sealant layer of the resulting packaging material with the tearing direction aligned with the longitudinal direction of the paper base material 2 . A notch in the longitudinal direction (coincident with the longitudinal direction of the paper base material 2) was formed in the upper seal portion of the pillow bag of Comparative Example 4.

(Comparative Example 5)
A pillow bag of Comparative Example 5 was produced in the same process as Comparative Example 4 except that the sealant layer was heat-sealed with the tearing direction aligned with the lateral direction of the paper substrate 2 . A notch portion was formed in the vertical direction (coincident with the horizontal direction of the paper substrate 2) in the upper seal portion of the pillow bag of Comparative Example 5.

(Comparative Example 6)
A packaging material used in Comparative Example 6 was produced by a non-solvent lamination method.
Using a sealant layer (CPP, monolayer film of ethylene-propylene block copolymer, thickness 25 μm) on which a 50 nm-thick aluminum vapor deposition film is formed, the same adhesive as in Comparative Example 4 is applied on the aluminum vapor deposition film, and the thickness A 3 μm adhesive layer was formed. Next, the adhesive layer and the glossy surface of the paper base material 2 were laminated to prepare a packaging material of Comparative Example 6.
A pillow bag of Comparative Example 6 was produced by heat-sealing the sealant layer of the resulting packaging material with the tearing direction aligned with the longitudinal direction of the paper base material 2 . A notch in the longitudinal direction (coincident with the longitudinal direction of the paper substrate 2) was formed in the upper seal portion of the pillow bag of Comparative Example 6.

(Comparative Example 7)
A pillow bag of Comparative Example 7 was produced in the same process as in Comparative Example 6 except that the sealant layer was heat-sealed with the tearing direction aligned with the lateral direction of the paper substrate 2 . A notch portion was formed in the vertical direction (coincident with the horizontal direction of the paper base material 2) in the upper seal portion of the pillow bag of Comparative Example 7.

(Comparative Example 8)
A packaging material used in Comparative Example 8 was produced by a dry lamination method.
A gas barrier adhesive (adhesive for dry lamination, manufactured by DIC Corporation, trade name “PASLIM”) was applied onto the sealant layer (CPP, monolayer film of ethylene-propylene block copolymer, thickness 25 μm) to a thickness of 3 μm. to form an adhesive layer. Next, the adhesive layer and the glossy surface of the paper base material 2 were laminated to prepare a packaging material of Comparative Example 8.
A pillow bag of Comparative Example 8 was produced by heat-sealing the sealant layer using the resulting packaging material with the tearing direction aligned with the longitudinal direction of the paper base material 2 . A notch in the longitudinal direction (coincident with the longitudinal direction of the paper substrate 2) was formed in the upper seal portion of the pillow bag of Comparative Example 8.

(Comparative Example 9)
A pillow bag of Comparative Example 9 was produced in the same process as in Comparative Example 8 except that the sealant layer was heat-sealed with the tearing direction aligned with the lateral direction of the paper base material 2 . A notch portion was formed in the vertical direction (coincident with the horizontal direction of the paper base material 2) in the upper seal portion of the pillow bag of Comparative Example 9.

4. result

All of the packaging bags of Examples had good openability. On the other hand, all of Comparative Examples 4 to 7 using plain paper showed poor opening properties.
In addition, the packaging materials of Comparative Examples 1 to 3, in which the rough surface was used as the adhesive surface, could not apply the adhesive uniformly, resulting in poor adhesion, and did not satisfy the quality as a packaging material.

INDUSTRIAL APPLICABILITY The present invention is useful in that, unlike conventional products, it is possible to obtain a packaging bag excellent in tearability in one direction, and a packaging material used for the packaging bag.

100, 200 packaging material 110, 210 paper substrate 120, 220 adhesive layer 130, 320 sealant layer 140, 240 pattern layer 232 gas barrier layer 300 packaging bag 310 lower seal portion 320 upper seal portion 330 back seal portion

Claims (8)

A packaging material for an easy-open packaging bag , comprising a paper substrate, an adhesive layer in contact with the paper substrate, and a sealant layer laminated in this order,
The paper substrate has a density of 0.50 g/cm ³ or more and 0.67 g/cm ³ or less,
The sealant layer is a non-stretched film,
When the tensile strength of the packaging material in the first direction is defined as σ ₁ and the tensile strength in the second direction perpendicular to the first direction is defined as σ ₂ , the packaging material satisfies conditional expression (1). ,
Ra ₁ is the arithmetic mean roughness of the adhesive layer side surface of the paper base material in the first direction, and Ra is the arithmetic mean roughness of the adhesive layer side surface of the paper base material in the second direction. ₂ , the paper substrate satisfies conditional expression (2),
A packaging material in which the ratio B/A of the thickness B (μm) of the adhesive layer to the thickness A (μm) of the paper substrate satisfies the following conditional expression (5) .
σ ₁ /σ ₂ ≧2.0 (1)
(Ra ₁ +Ra ₂ )/2≦3.0 μm (2)
0.02≤B/A≤0.50 (5) 2. The packaging material of claim 1, wherein the adhesive layer and the sealant layer are in contact. The packaging material according to claim 1, further comprising a gas barrier layer between the adhesive layer and the sealant layer, the gas barrier layer and the sealant layer being in contact with each other, and the gas barrier layer and the adhesive layer being in contact with each other. Ra ₃ is the arithmetic mean roughness of the surface of the paper base opposite to the adhesive layer in the first direction, and the arithmetic mean of the surface of the paper base opposite to the adhesive layer in the second direction 4. The packaging material according to any one of claims 1 to 3, wherein the paper substrate satisfies the following conditional expressions (3) and (4) when the roughness is defined as Ra ₄ .
Ra ₃ >Ra ₁ (3)
Ra ₄ >Ra ₂ (4) The packaging material according to any one of claims 1 to 4 , wherein the adhesive layer has a thickness of 1 µm or more and 15 µm or less. The packaging material according to any one of claims 1 to 5 , wherein the paper substrate has an air permeability of 20 s/100 ml or less according to JIS P8117:2009. A packaging bag formed of the packaging material according to any one of claims 1 to 6 , wherein the sealant layer is an inner layer. A method for manufacturing the packaging material according to any one of claims 1 to 7 ,
forming the adhesive layer on one surface of the sealant layer by either a non-solvent lamination method or a dry lamination method;
A method for producing a packaging material, comprising: laminating the paper substrate on the adhesive layer side surface of the sealant layer, and bonding the adhesive layer and the paper substrate.

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