JP2021094814A - Paper packaging bag, paper packaging material for the same, and method of producing the same - Google Patents

Abstract

To provide a paper packaging material capable of improving recyclability and design printing reproducibility, a paper packaging bag using the same, and a method of producing the same.SOLUTION: A method of producing a paper packaging material of this invention includes the steps of: coating a releasing agent on a base material film 21 to form a surface protective layer 22 made of a cured film of the releasing agent; printing on the surface protective layer 22 a design layer 23, a design of which is formed of ink, to form a transfer film 25; forming on one surface of a paper base material 28 a heat adhesive resin layer 29 on which a heat adhesive resin is printed; bonding the other surface of the paper base material 28 and the design layer 23 of the transfer film 25 with an adhesive agent 24 made of an adhesive; and releasing the base material film 21.SELECTED DRAWING: Figure 2

Description

The present invention relates to a paper packaging material having a thermosetting resin layer and a method for producing the same. The present invention also relates to a paper packaging bag that is sealed by thermal adhesion.

A conventional paper packaging bag is disclosed in Patent Document 1. This paper wrapping bag is formed of a paper wrapping material having a thermosetting resin layer provided on one surface of a paper base material. A printing layer for printing a pattern is provided on the other surface of the paper base material. The thermosetting resin layer is formed by dry-laminating a resin film on one surface of a paper base material. A paper packaging bag is formed by arranging the thermosetting resin layer on the inner surface side and heat-bonding the opposing thermosetting resin layers.

Japanese Unexamined Patent Publication No. 2019-38546 (pages 4 to 8, FIG. 6)

However, according to the conventional paper packaging bag, there is a problem that the recyclability is poor because the thermosetting resin layer is formed of the resin film. Further, since the surface smoothness of the paper base material is low, there is a problem that the print reproducibility of a pattern such as a gradation formed by the print layer on the paper base material is deteriorated. This makes it difficult to obtain a paper packaging bag with a high aesthetic appearance.

An object of the present invention is to provide a paper wrapping material capable of improving recyclability and print reproducibility of a pattern, and a method for manufacturing a paper wrapping bag and a paper wrapping material using the same.

In order to achieve the above object, the method for producing a paper packaging material of the present invention includes a step of applying a release agent on a base film to form a surface protective layer made of a cured film of the release agent, and the surface protection. A step of printing a pattern layer for forming a pattern with ink on a layer to form a transfer film, a step of printing a heat-adhesive resin on one surface of a paper base material, and a step of printing the other surface of the paper base material and the transfer film. It is characterized in that it includes a step of adhering the design layer to the design layer with an adhesive and a step of peeling off the base film.

Further, the present invention is characterized in that, in the method for producing a paper packaging material having the above structure, the adhesive layer penetrates between the design layers and is adhered to the surface protective layer.

Further, the present invention is characterized in that, in the method for producing a paper packaging material having the above structure, the surface protective layer is formed by an acrylic release agent.

Further, the present invention is characterized in that the thermosetting resin layer is formed of an aqueous resin film in the method for producing a paper packaging material having the above structure.

Further, the paper packaging material of the present invention includes a heat-adhesive resin layer in which a heat-adhesive resin is printed on one surface of a paper base material, an adhesive layer composed of an adhesive arranged on the other surface of the paper base material, and an ink. It is characterized by having a design layer formed on the adhesive layer and arranged on the adhesive layer, and a surface protective layer made of a cured film of a release agent arranged on the design layer.

Further, the present invention is characterized in that, in the paper packaging material having the above structure, the adhesive layer penetrates between the design layers and is adhered to the surface protective layer.

Further, the paper packaging bag of the present invention is characterized in that it is formed in a bag shape by thermal adhesion of the heat-adhesive resin layer facing the paper packaging material having the above structure.

According to the method for producing a paper packaging material of the present invention, the base film is peeled off after adhering the paper base material to the transfer film provided with the surface protection layer and the design layer made of the cured film of the release agent on the base film. Will be done. As a result, the design layer formed on the highly smooth base film is transferred to the paper base material, so that the print reproducibility of the design layer can be improved. Further, since the thermosetting resin layer is formed by printing and the extruded resin is not provided in the lower layer of the design layer, the amount of resin used in the paper packaging material can be reduced. Thereby, the recyclability of the paper wrapping material and the paper wrapping bag can be improved. At this time, the decrease in the air permeability resistance of the paper packaging material can be suppressed by the adhesive layer and the surface protective layer.

Further, according to the paper wrapping material and the paper wrapping bag of the present invention, a heat-adhesive resin layer is printed on one surface of a paper base material, and the other surface is composed of a design layer and a cured film of a release agent via an adhesive layer. A surface protective layer is arranged. Therefore, the design layer can be formed on the highly smooth base film and transferred to the paper base material, and the print reproducibility of the design layer can be improved. In addition, it is possible to suppress a decrease in air permeability resistance, reduce the amount of resin used in the paper wrapping material, and improve the recyclability of the paper wrapping material and the paper wrapping bag.

Schematic cross-sectional view showing a layer structure showing a paper packaging material according to an embodiment of the present invention. Schematic cross-sectional view showing the manufacturing process of the paper packaging material of the embodiment of the present invention. Front view showing a paper wrapping bag formed by the paper wrapping material of the embodiment of the present invention.

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic cross-sectional view showing a layer structure of the paper packaging material 20 of one embodiment. The paper wrapping material 20 makes a paper wrapping bag 1 (see FIG. 3). In the paper packaging material 20, the thermosetting resin layer 29 is arranged on one surface of the paper base material 28, and the design layer 23 and the surface protective layer 22 are arranged on the other surface via the adhesive layer 24.

The paper base material 28 is not particularly limited, but high-quality paper, thin imitation paper, bleached kraft paper, unbleached kraft paper, single-gloss kraft paper, heavy-duty kraft paper, pure white roll paper, glassin paper, white paperboard, paper tube base paper, Liner base paper, clay coated paper, recycled paper and the like can be used. The paper base material 28 may be a single-layer paper or a multi-layer paper.

The basis weight of the paper base material 28 is preferably ^{25 to 125 g / m 2.} If the basis weight of the ^{paper base material 28 is smaller than 25 g / m 2} , the paper packaging material 20 is easily torn, and if it ^{is larger than 125 g / m 2,} it becomes difficult to form a bag shape.

The heat-adhesive resin layer 29 is composed of a printed coating film of the heat-adhesive resin, and is formed by printing a water-based heat-adhesive resin on a paper base material 28. As a result, the thermosetting resin layer 29 is formed of the water-based resin film.

The aqueous resin film is a resin film obtained by drying a liquid in which a resin is dissolved or dispersed in an aqueous medium or a hydrophilic medium. Specifically, a resin film in which a surfactant for dissolving or dispersing the resin remains in the medium, a resin containing highly hydrophilic carboxylic acid, sulfonic acid, etc. in the resin skeleton and which can be dissolved or dispersed in the medium. Examples thereof include a resin film formed of (1) and a resin film in which these coexist.

The printing liquid of the thermosetting resin may be a water-soluble type or a water-dispersed type (colloidal dispersion type, emulsion type). The paper packaging bag 1 (see FIG. 3) is formed by superimposing the opposing thermosetting resin layers 29 on top of each other, pressurizing and heating them to heat-bond them.

Specific examples of the water-based thermosetting resin include water-based acrylic emulsions, water-based polyolefins (polyethylene, EMA, EMAA, EVA, ionomer, etc.) and the like.

Since the heat-adhesive resin layer 29 is made of a printed coating film, the amount of resin used in the paper packaging material 20 can be reduced and recyclability can be improved. Further, since the thermosetting resin layer 29 is formed of the water-based resin film, the releasability of the paper packaging material 20 at the time of recycling is improved. Thereby, the recyclability of the paper packaging material 20 can be further improved.

Further, the aqueous resin film does not contain a so-called oily organic solvent (toluene, MEK, ethyl acetate, etc.) when formed. As a result, it is possible to prevent the odor due to the residual solvent of the thermosetting resin layer 29 arranged on the inner surface side of the paper packaging bag 1 (see FIG. 3). Therefore, the paper packaging material 20 can be used as a food paper packaging material suitable for food packaging. The thermosetting resin layer 29 may be formed of a non-aqueous resin, although the dissociation property is lowered in the case of an application in which a residual solvent is allowed.

The surface protective layer 22 and the design layer 23 are provided on the base film 21 (see FIG. 2) described later, and are adhered to the paper base material 28 by the adhesive layer 24. The adhesive layer 24 is formed of an adhesive such as an acrylic adhesive or a urethane adhesive.

The surface protective layer 22 is formed by a cured film of a transparent release agent. As the release agent for forming the surface protective layer 22, a silicone-based release agent, a fluorine-based release agent, an acrylic-based release agent, an alkyd-based release agent, a long-chain alkyl-based release agent, or the like can be used. The acrylic resin used for the acrylic release agent is more desirable because it can be designed with a wide degree of polymerization and can be designed and used according to the base material and the release property.

The design layer 23 is composed of a printed coating film in which ink is printed on the surface protective layer 22, and forms a desired design (including characters). The plurality of inks forming the design layer 23 are mainly composed of urethane-based resin, nitrified cotton resin, and the like, and contain colored pigments such as cyan, magenta, yellow, and black, and white pigments, respectively.

2 (a) to 2 (d) are schematic cross-sectional views showing a manufacturing process of the paper packaging material 20. The paper packaging material 20 is manufactured by a release agent coating step, a pattern printing step, a heat-adhesive resin layer forming step, an bonding step, and a peeling step.

As shown in FIG. 2A, the release agent coating step applies a release agent on a resin base film 21 such as polyethylene terephthalate, and cures the film by drying, heating, irradiating with ultraviolet rays, or the like. The amount of the release agent applied is, for example, 1 to 3 g / m ² . As a result, the surface protective layer 22 made of a cured film of the release agent is formed.

In the symbol printing step, as shown in FIG. 2B, the symbol layer 23 forming the symbol is printed on the surface protective layer 22. As a result, the transfer film 25 having the surface protective layer 22 and the design layer 23 provided on the base film 21 is formed. The design layer 23 is dispersedly provided at a desired position on the base film 21, but may be provided on the entire surface.

As shown in FIG. 2C, the thermosetting resin layer forming step is performed by printing a water-based thermosetting resin having a ^{solid content of, for example, 1 to 20 g / m 2 on one surface of the paper base material 28.} Form layer 29. If the amount of the thermosetting resin ^{is less than 1 g / m 2} , the sealing strength of the heat-bonded portion of the paper packaging bag 1 (see FIG. 3) described later cannot be obtained. If the amount of resin in the thermosetting resin layer 29 is ^{more than 20 g / m 2} , the amount of resin used increases and the printing characteristics deteriorate.

In the bonding step, as shown in FIG. 2D, an adhesive is applied to the other surface of the paper base material 28 (the surface opposite to the thermosetting resin layer 29) at, for example, ² to 5 g / m 2, and the transfer film is formed. The adhesive layer 24 is formed by adhering to the design layer 23 of 25. When the symbol layers 23 are provided in a dispersed manner, the adhesive layer 24 enters between the symbol layers 23 and is adhered to the surface protective layer 22.

In the peeling step, the base film 21 is peeled off after the bonding step. As a result, the design layer 23 and the surface protection layer 22 are transferred onto the paper base material 28, and the paper packaging material 20 (see FIG. 1) is obtained.

The design layer 23 is printed on the highly smooth base film 21 via the surface protective layer 22. Therefore, the print reproducibility of a symbol such as a gradation formed by the symbol layer 23 can be improved.

Even if a base layer such as an extruded resin or a resin film is provided on the paper base material 28 and the design layer 23 is printed on the base layer, the printed surface of the design layer 23 can be formed with high smoothness. However, the amount of resin used increases depending on the base layer, and the dissociation property of the paper packaging material 20 at the time of recycling deteriorates. Therefore, by printing the design layer 23 on the base film 21 removed in the peeling step and transferring it to the paper base material 28, the amount of resin used in the paper packaging material 20 can be reduced and the dissociation property can be improved. .. Thereby, the recyclability of the paper wrapping material 20 and the paper wrapping bag 1 (see FIG. 3) formed by the paper wrapping material 20 can be improved.

FIG. 3 shows a front view of the paper packaging bag 1 formed of the paper packaging material 20. The paper packaging bag 1 is formed in a pillow shape having a back seal portion 2 and an edge seal portion 3. A storage unit 9 for storing the contents 10 is provided inside the paper packaging bag 1. The content 10 is composed of individually wrapped (primary packaging) foods (confectionery, etc.), chemicals, etc., and the paper packaging bag 1 secondary wraps the content 10.

The back seal portion 2 is formed by heat-bonding the heat-adhesive resin layers 29 (see FIG. 1) facing each other on both side ends of the body portion 5 in which the paper packaging material 20 is arranged in a tubular shape. The edge sealing portions 3 and 4 are formed by thermally adhering a thermosetting resin layer 29 facing both ends of the body portion 5 in the axial direction. Both ends of the body portion 5 in the axial direction are formed in a sawtooth shape, for example, for opening.

The contents 10 are filled in the storage portion 9 and the heat-adhesive resin layers 29 facing each other are heat-bonded, so that the contents 10 are enclosed in the paper packaging bag 1.

In the paper packaging material 20, the adhesive layer 24 and the surface protective layer 22 are arranged on the paper base material 28. Therefore, the decrease in the air permeation resistance of the paper packaging material 20 due to the formation of the thermosetting resin layer 29 by printing is suppressed. The air permeation resistance is the time for 100 mL of air to permeate per unit area and unit pressure difference, as defined in JIS P8117: 2009. Therefore, the outflow of air filling the inside of the paper packaging bag 1 is suppressed, and the contents 10 can be protected during transportation and storage of the paper packaging bag 1 in which the contents 10 are enclosed.

As an example, the air permeability resistance of the paper wrapping paper 20 was measured and found to be 15,000 seconds. The paper base material 28 of the paper wrapping paper 20 was single-gloss kraft paper (basis weight 64 g / m ² ). The thermosetting resin layer 29 was printed with a printing solution of an aqueous polyolefin dispersion having a solid content of 4 g / m ^{2 to a thickness of about 3 to 4 μm.} The surface protective layer 22 was formed by applying acrylic nitrocellulose cotton at 3 g / m ² , and the adhesive layer 24 was formed by applying an acrylic adhesive on a paper base material 28 at 3 g / m ² .

For comparison, the design layer 23 was printed on the paper base material 28 to omit the adhesive layer 24 and the surface protective layer 22, and the air permeability resistance of the other paper wrapping paper formed in the same manner as above was 50 seconds. It was.

Although the paper packaging bag 1 is formed in a pillow shape, it may be formed in another form such as a self-standing bag, a sealed four-sided sticker bag, or a three-way sticker bag before sealing. Further, although the paper packaging bag 1 is used for the secondary packaging, it may be used for the primary packaging.

According to the present embodiment, the base film 21 is peeled off after the transfer film 25 provided with the surface protective layer 22 and the design layer 23 made of a cured film of the release agent on the base film 21 and the paper base material 28 are adhered to each other. To. As a result, the design layer 23 formed on the highly smooth base film 21 is transferred to the paper base material 28, so that the print reproducibility of the design layer 23 can be improved.

Further, a thermosetting resin layer 29 is printed on one surface of the paper base material 28, and a surface protective layer 22 composed of an adhesive layer 24, a design layer 23, and a cured film of a release agent is arranged in this order on the other surface. Therefore, by forming the design layer 23 on the highly smooth base film 21 and transferring it to the paper base material 28 by the adhesive layer 24, the print reproducibility of the design layer 23 can be improved.

Further, since the thermosetting resin layer 29 is formed by printing and the extruded resin or the like is not provided in the lower layer of the design layer 23, the amount of resin used in the paper packaging material 20 can be reduced. Thereby, the recyclability of the paper wrapping material 20 and the paper wrapping bag 1 can be improved. At this time, the adhesive layer 24 and the surface protective layer 22 can suppress a decrease in the air permeability resistance of the paper packaging material 20. Therefore, the content 10 can be protected during transportation and storage of the paper packaging material 20 in which the content 10 is enclosed.

Further, since the adhesive layer 24 enters between the design layers 23 and is adhered to the surface protective layer 22, it is possible to prevent the surface protective layer 22 from peeling off.

Further, since the surface protective layer 22 is formed of an acrylic release agent, it can be designed and used according to the base film 21 and the release property, and the paper packaging material 20 can be easily formed.

Further, since the heat-adhesive resin layer 29 is formed of the water-based resin film, the releasability of the paper packaging material 20 can be improved and the recyclability can be further improved. In addition, the paper packaging bag 1 for food can be easily formed by preventing the odor caused by the residual solvent.

According to the present invention, it can be used as a packaging bag for foods and the like.

1 Paper packaging bag 2 Back seal part 3, 4 Edge seal part 5 Body part 9 Storage part 10 Contents 20 Paper packaging material 21 Base film 22 Surface protection layer 23 Design layer 24 Adhesive layer 25 Transfer film 28 Paper base Material 28a Coat layer 29 Heat-adhesive resin layer

Claims (7)

A step of applying a release agent on a base film to form a surface protective layer made of a cured film of the release agent, and
A step of printing a pattern layer for forming a pattern with ink on the surface protective layer to form a transfer film, and a process of forming a transfer film.
The process of printing thermosetting resin on one side of the paper substrate,
A step of adhering the other surface of the paper base material and the design layer of the transfer film with an adhesive,
The step of peeling the base film and
A method for manufacturing a paper packaging material, which is characterized by being provided with. The method for producing a paper packaging material according to claim 1, wherein the adhesive layer penetrates between the design layers and is adhered to the surface protective layer. The method for producing a paper packaging material according to claim 1 or 2, wherein the surface protective layer is formed of an acrylic release agent. The method for producing a paper packaging material according to any one of claims 1 to 3, wherein the heat-adhesive resin layer is formed of an aqueous resin film. A heat-adhesive resin layer in which a heat-adhesive resin is printed on one surface of a paper base material, an adhesive layer composed of an adhesive arranged on the other surface of the paper base material, and a pattern formed by ink on the adhesive layer. A paper packaging material comprising a design layer arranged on the pattern layer and a surface protective layer made of a cured film of a release agent arranged on the design layer. The paper packaging material according to claim 5, wherein the adhesive layer penetrates between the design layers and is adhered to the surface protective layer. A paper packaging bag according to claim 5 or 6, wherein the paper packaging material is formed into a bag shape by thermal adhesion of the heat-adhesive resin layers facing each other.

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