JP2014141272A - Paper container for liquid and production method of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a paper container for liquid capable of being produced by using a production line of a paper container in which conventional normal skive hemming processing is performed, or a production line in which only an end surface of an inside is folded and a base material end surface toward the inside is not exposed, and capable of protecting a cross section of the base material end surface from moisture from an outside and osmosis of surfactant easily at low cost.SOLUTION: In a paper container for liquid, an inside to which a paper end surface is exposed is subjected to edge protect, and an outside paper end surface to which the paper end surface is exposed is covered with thermoplastic resin.

Description

  The present invention mainly relates to a liquid paper container that contains a liquid containing a surfactant, such as shampoo, body soap, and house detergent, and uses paper as a base material.

Conventionally, laminated sheets used for liquid paper containers have a configuration in which paper is used as a base material, and the inner side surface and outer side surface are made of polyolefin resin having excellent heat sealability. Depending on the components of the contents, gas barrier properties can be used. The layer which gives was added. For example, in juice and liquor, it is composed of a laminated sheet 5 such as [container outside] polyethylene / paper / polyethylene / inorganic oxide vapor deposition layer / polyethylene terephthalate (hereinafter abbreviated as PET) film / polyethylene [container inside]. Such a structure is widely used as a container filled with a liquid requiring fragrance retention or a liquid that easily oxidizes.
The paper containers used for these foods have been subjected to edge protection treatment that covers and protects the end face represented by skive hemming so that the base paper does not enter the inner surface. However, in order to use as a container for storing a highly permeable content such as a surfactant as a content, there has been a serious problem only by treating the inner end face of the substrate.
That is, if the paper end surface of the base material is exposed, the base material end surface may be swollen due to the adhesion of moisture, and by this, moisture penetrates deeper into the interior from the end surface. There has been a problem that the strength such as rigidity deteriorates.
In particular, when the content containing the surfactant adheres to the end face, the permeability is much higher than that of water alone, and the paper fibers are separated to significantly reduce the strength and the strength of the container. If the strength of the container is reduced in this way, even if you try to grab the torso, it will become too soft and you will not be able to tilt the container with one hand or make it impossible to stand the container. Had occurred.

On the other hand, in Document 1, the base material layer punched end surface of the laminated material pasted inside the container of the back pasting portion, the synthetic resin layer laminated on the outside of the base material layer and the synthetic resin layer laminated on the inside We propose an edge-protected liquid paper container covered with
However, this method requires a thick low melting point thermoplastic resin layer on both sides. Further, when a resin layer having a high melting temperature such as PET is put in the laminated synthetic resin layer, a problem that it is difficult to flow easily occurs. In addition, in this document, it is assumed that only the end surface on the inner surface side is covered, and there are problems that cannot be solved with respect to the problems of the present invention, such as a reduction in strength due to moisture penetrating from the outside or penetration of a surfactant.

In the literature 2, in the skive and hemming process of the edge of the laminated sheet, as the edge moves inward from the tip by a predetermined width from the tip, the depth of removing the outer side of the laminate has a slope that becomes continuously shallower. A method for forming a deleted portion having a trapezoidal cross-sectional shape is described.
This method requires special equipment dedicated to skive and hemming processing. Also, when a layer with high thermal conductivity such as metal foil is laminated on the laminated sheet, the thermal conductivity at the time of thermal fusion is not uniform. There was a problem with the stability of the sealing process.
Also in this document, it is assumed that only the end surface on the inner surface side is covered. It is because applying this processing to the entire periphery where the substrate end face occurs, the connection between the peripheral part of the roll paper of the equipment and the use part becomes very weak, and it can not be practically used in the process, There was a problem that it was not possible to cope with the problems of the present invention, such as moisture permeating from the outside and a decrease in strength due to penetration of the surfactant.

In Document 3, when the container is molded, the base material portion that becomes the end face of the paper base material layer is perforated by a printing long hole drilling process, and a polyethylene tape and a molten polyethylene resin film covering the long hole are covered, A method for manufacturing an edge-protected blank in which the long holes are divided and a protective film protrudes from the end face of the laminated paper is proposed.
Although this method can reliably cover the end face of the substrate, there is a problem that the container forming part falls off from the roll paper of the base material when trying to cover the entire end face. There is a problem that only a part of can be used. For this reason, there is a problem in that mass productivity is lost when the entire end face is protected. For this reason, in the prior art, in order to ensure mass productivity, there has been a problem that cannot be coped with the problem of the present invention because it must be used only on the end face on the inner surface side that is particularly required.

Japanese Utility Model Publication No. 7-26318 Japanese Patent No. 4122822 Japanese Patent No. 4325309

  Therefore, using a conventional paper container production line that can perform normal skive hemming processing, or a production line that only bends the inner end face and does not expose the end face to the inside, the base material can be easily and inexpensively It is an object of the present invention to obtain a liquid paper container capable of protecting the cross section of the end face from moisture and surfactant penetration from the outside.

  The invention according to claim 1 is a paper container for storing liquid, wherein the inner side where the paper end face is exposed is edge-protected, and the outer paper end face where the paper end face is exposed is covered with a thermoplastic resin. It is.

  The invention according to claim 2 is a liquid paper container characterized in that the thermoplastic resin is a hot melt resin.

  According to a third aspect of the present invention, in the method of manufacturing a paper container for storing a liquid, the inner side where the paper end surface is exposed is edge-protected, and after forming into a container shape, the outer paper end surface where the paper end surface is exposed is covered with a thermoplastic resin This is a method for manufacturing a liquid paper container.

The liquid paper container of the present invention covers the cross section of the base material, both inside and outside the container, even if the content contains a highly penetrating surfactant, so that the base paper permeates and burns. In addition, since there is no strength reduction such as rigidity, the container can be used without any change in handling.
In addition, since a normal paper container line can be used, the function of the present invention can be easily added only by adding an injection gun that covers the thermoplastic resin.

It is the external view seen from the back seal side of the liquid paper container of this invention. It is the external view seen from the mouth side of the liquid paper container of this invention. It is the external view seen from the bottom face side of the liquid paper container of this invention. It is the shape of the blank seen from the surface side of the main-body part which carried out the skive process in the manufacturing process of the liquid paper container of this invention. FIG. 7 is a cross-sectional view of a trunk back seal portion subjected to skive hemming treatment at the time of forming the container in the manufacturing process of the liquid paper container of the present invention. FIG. 5 is a cross-sectional view showing a state in which a thermoplastic resin is applied to an end surface of a liquid paper container of the present invention after container formation of a trunk back seal portion that has been skived and hemmed; In the manufacturing process of the liquid paper container of the present invention, the shape of the blank is viewed from the surface side of the main body portion that is edge-protected by bending the end surface. In the manufacturing process of the liquid paper container of this invention, it is sectional drawing at the time of container shaping | molding of the trunk | drum back seal part which bent the end surface and edge protected. FIG. 5 is a cross-sectional view showing a state in which a thermoplastic resin is applied to the end face of the liquid paper container according to the present invention after forming the container of the trunk back seal portion where the end face is bent and edge-protected. It is sectional drawing in the gable top of the liquid paper container of this invention. It is sectional drawing in the bottom face seal part of the liquid paper container of this invention. It is sectional drawing of the stopper vicinity in the gable top of the liquid paper container of this invention. It is an external view of the shape which employ | adopted the flat top of the liquid paper container of this invention. It is the shape of the blank seen from the surface side used for the flat top of the liquid paper container of this invention. It is sectional drawing of the stopper vicinity in the flat top of the liquid paper container of this invention.

Hereinafter, embodiments of the spout stopper used for the liquid paper container of the present invention will be described in detail with reference to the drawings.
The paper container body used in the embodiment has a shape as shown in FIGS. 1 to 3, uses paper as a base material, and heats the inner surface fusion layer 51 and the outer surface fusion layer 53 with excellent heat sealability. A laminated sheet 5 is used as a plastic resin. The body part is bonded with the side adhesive part 41, and the top part and the bottom part are joined together to form a quadratic container body 3 and a gable roof-shaped gable top. 31 is a liquid paper container in which a spigot attachment hole 2 is opened in 31 and a spout spout 1 is projected from the spigot attachment hole portion. The end surface covering portion 54 is a portion where the end surface is exposed to the outside, and covers the exposed end surface to prevent penetration of the surfactant.
FIG. 2 is an external view as viewed from the opposite side of FIG. 1, and there is also an end face covering portion 54 around the inner surface of the plug attachment hole 2. FIG. 3 is an external view at an angle at which the bottom surface side can be seen, and the end surface covering portion 54 is provided continuously along the side surface seal portion at the corner of the side surface from the bottom surface.

The container as shown in FIGS. 1 to 3 is obtained by punching the laminated sheet 5, bending it, and fusing it.
FIG. 4 shows an example of a blank subjected to skive treatment, and has edge portions such as skive portions 411, 421, and 431 formed by scraping the substrate.
The skived portion is folded back so that the cut portion is inside, and the end surface of the substrate is covered with a thermoplastic resin.
The top surface portion 323 is provided with a stopper mounting hole 2 for fusing the spout stopper 1.
The bottom surface is folded back so that the end surface of the laminated sheet 5 does not appear on the inner surface.
A paper container is shape | molded by each folding the mountain fold line 6 and the valley fold line 7, and fuse | melting a mating surface.

FIG. 5 is an enlarged view of the side seal portion of the container formed with the blank of FIG.
The skived side skive processing part 411 is fused to the inner surface fusion layer 51 inside the side part 311 and covers the substrate end face of the side adhesion part 41.
However, in this state, the end surface of the side surface portion 311 that is on the outside is exposed, and water or the like is expected to permeate from the base material layer 52 on the end surface.

FIG. 6 is a cross-sectional view in which the end surface of the side surface portion 311 exposed in FIG. 5 is covered with a thermoplastic resin 54. The thermoplastic resin may be a thermoplastic resin such as a polyethylene resin, an ethylene / vinyl acetate copolymer resin, or a hot melt resin.
To cover, an injection gun such as a hot melt gun can be used for easy coating. A portion where the end face is exposed to the outside of the molded paper container is arranged upward, and a thermoplastic resin melted in a string shape is injected and dropped from above. At this time, it is necessary to cover the molten thermoplastic resin so that the end surface of the base material layer 52 is not exposed to the outside even if it covers both the end surface of the inner surface fusion layer 51 and the end surface of the outer layer fusion layer 53 on the end surface of the laminated sheet. . Immediately after dropping, it is preferable to compress and cool while pressing with a pressing roll.

FIG. 7 shows a blank that does not skive and folds the fused part to protect the inner edge.
The side surface fusion part 41 is bent 180 degrees along the valley fold line 7 on the edge side, and is fused to the inner surface fusion layer 51 of the side part 311 with the innermost inner surface fusion layer 51 facing outward.

FIG. 8 is a cross-sectional view of the vicinity of the side folded portion 412 of the paper container formed by folding the blank of FIG. 7 along the mountain fold line 6 and the valley fold line 7 and fusing the mating surfaces.
In the folded side surface folding processing portion 412, the outer surface fusion layers 53 are fused to each other, the inner surface fusion layer 51 is turned over to face the outside, and the side surface portion is turned to the inverted inner surface fusion layer 51. The base material end surface of the side surface bonding portion 41 is covered by being fused to the inner surface fusion layer 51 inside 311.
However, in this state, the end surface of the side surface portion 311 that becomes the outer side and the end surface of the side surface folded-back fusion portion 412 are exposed, and water or the like is expected to permeate from the base material layer 52 on the end surface.

FIG. 9 is a cross-sectional view in which the end surface of the side surface portion 311 and the end surface of the side surface folded fusion portion 412 formed and exposed in FIG. 8 are covered with the thermoplastic resin 54.
At this time, the melted thermoplastic resin is applied to both the end surface of the outer layer fusion layer 53 of the folded portion 312 and the end surface of the outer layer layer 53 of the side surface portion 311, and the folded portion 312 and the side surface portion 311 therebetween. It is necessary to cover so that the end face of the base material layer 52 is not exposed to the outside.

FIG. 10 is a view showing a cross section of the pull top.
The top surface portions 322 and 324 are valley-folded, wrap around the inside of the top surface portions 321 and 323, and the inner surface fusion layer 51 of the top surface portions 322 and 324 and the inner surface fusion layer 51 of the top surface portions 321 and 323 are fused. .
Although the end surface of the base material layer 52 of the top surface portions 322 and 324 is covered with the inner surface fusion layer 51 of the top surface portions 321 and 323, the end surface of the base material layer 52 of the top surface portions 321 and 323 is exposed. It will be covered with a thermoplastic resin 54.

FIG. 11 shows the fused state of the bottom surface.
The bottom surface portions 332 and 334 are valley-folded, and are sandwiched between the bottom surface portions 331 and 333 to move the end surfaces to the outside, and the inner surface fusion layer 51 of the bottom surface portions 332 and 334 and the inner surface fusion layer 51 of the bottom surface portions 331 and 333. And fuse.
Although the end surface of the base material layer 52 of the bottom surface portions 332, 333, and 334 is covered with the inner surface fusion layer 51 of the top surface portion 331, the end surface of the base material layer 52 of the top surface portion 321 is exposed. The portion 54 is covered with a thermoplastic resin.

FIG. 12 is a cross-sectional view of the vicinity of the spout stopper 1 with a hinge cap and a pull-top spout spout 1 fused thereto.
Usually, the flange 11 of the spout stopper 1 is fused to the inside of the paper container, and the spout stopper 1 is fused so as to protrude from the spigot attachment hole 2.
The periphery of the plug attachment hole 2 is also covered with the thermoplastic resin of the end surface covering portion 54 so that the base material is not exposed.

FIG. 13 shows a paper container employing a flat top.
As for the top surface, the top surface portions 321 and 323 protrude left and right by mountain folding, the inner surfaces where the tips meet are fused, the inner surfaces of the top surface portion 322 and the top surface portion 324 are fused together, and the fusion start line of the top surface portion 322 Folded into a valley fold at position 3220, the top surface 324 tip is fused to the outer surface fusion surface of the top surface 322, and the top halves of the top surfaces 321 and 323 are fused to the side portions 311 and 313, respectively.
Since the top half portions of the top surfaces 321 and 323 and the top surface portion 324 are also exposed, the exposed portions are covered with the thermoplastic resin of the end surface covering portion 54.

  FIG. 14 is a blank of the paper container of FIG. In the case of a flat top, the hole position of the fold and the mouth has changed from the gable top.

  FIG. 15 shows a cross section of the top surface portion of the flat top, which is considerably simpler than that of the gable top. The end surface covering portion 54 covers not only the inner surface of the plug attachment hole 2 but also the end surface of the top surface portion 324 having the hole, and the top end portion 321 and the top end surface of the top surface portion 323.

Although the present invention is as described above, the configuration of the laminated sheet 5 forming the container is that the outermost surface and the innermost surface are made of thermoplastic resin, and if paper is used as the intermediate layer, it is deposited on the paper. A film having a high barrier property may be a lower intermediate layer, and the material is not particularly limited.
For example, polyethylene / paper / polyethylene,
Polyethylene / paper / polyethylene / inorganic oxide vapor-deposited polyethylene terephthalate / polyethylene,
Polyethylene / paper / polyethylene / aluminum-deposited polyethylene terephthalate / polyethylene,
Polyethylene / paper / polyethylene / aluminum foil / polyethylene terephthalate / polyethylene,
Examples include polyethylene / paper / polyethylene / ethylene vinyl acetate copolymer saponified product / polyethylene, polyethylene / paper / polyethylene / adhesive resin / polyamide / adhesive resin / polyethylene, and the like.

The material of the spout 1 is a material that has good adhesion to the sealant layer used in the container body, has high resistance to stress cracking, is hardly affected by the contents, and has a moderate rigidity. There must be something easy to capping.
Furthermore, when a pull ring is formed, the tensile strength needs to be high, and the annular thin-walled fragile wire needs to have various characteristics that break at a constant tensile strength. In particular, when a spout plug integrated with a cap such as a hinge cap is used, the fluidity (MIF) upon melting must be high.
Therefore, materials that can be used for the spout stopper 1 are low-density polyethylene of high pressure method, linear low-density polyethylene, medium-density polyethylene, mixed resin of low-density and high-density polyethylene, ionomer resin, ethylene vinyl acetate copolymer A resin in which a coalescence is added to and mixed with the above. Among these, linear low density polyethylene is preferable. When actually used, after molding using various resins, it is fused to the paper container body, and the content to be filled is used to conduct an environmental stress cracking test and make a judgment.

  Specific examples of the present invention will be described below.

<Example 1>
As the laminated sheet 5, create a sheet having the configuration shown in the table below,
A blank was formed into a blank shape shown in FIG. 7 with a paper container having a square bottom with a side of 70 mm and a capacity of 500 ml.

An ethylene / vinyl acetate copolymer hot melt agent was used for the top seal part, bottom seal part, side seal part and spout weld part, and the end face was covered with an injection gun to prevent the end face from being exposed.

<Comparative Example 1>
As the laminated sheet 5, a sheet having the same configuration as the example is created,
A blank was formed into a blank shape shown in FIG. 7 with a paper container having a square bottom with a side of 70 mm and a capacity of 500 ml.
The top seal part, the bottom seal part, the side seal, and the plug hole part with the exposed end surfaces were left exposed as they were.

  The evaluation results of Examples and Comparative Examples are as shown in the following table.

The liquid paper container of the present invention is as described above. Even if a liquid containing a surfactant such as a shampoo is put in or leaked to the outer surface, the liquid sheet container can be used. This is an effective method in that the physical properties of the container do not deteriorate and the appearance does not change.
In recent years, robots have become cheaper and can be used at lower prices, so liquid paper containers created with conventional molding lines can be exposed to the outside with simple teaching, whether they are paper-belt paper containers or flat-top paper containers. The end face can be covered with a hot melt gun or the like. The present invention has a great merit because the paper container can be easily improved in such a manner and can maintain a strength that can be used in a high humidity environment for a long period of time.

1 ... Spout plug 11 ... Flange 12 ... Hinge cap 2 ... Plug attachment hole 3 ················································································································· Gable-top fused portion 311 ...... Side portion 313 ........ Side portion 314 ........ Side portion 321 ........ Top portion 322 ........ Top portion 3220 .. ··· Fusion start line 323 ····················································································· ······························································.
411 ····· Side surface skive treatment portion 412 ····· Side-turned fused portion 42 ·········· Top surface adhesive portion 421 ·········· Portion 422... Top folded portion 43... Bottom adhesive portion 432... Bottom folded portion 5. Laminated sheet 51... Inner surface fusion layer 52... Base material layer 53... Outer surface fusion layer 54. Cover 6 ... Yamaori Line 7 ... Taniori Line

Claims (3)

  A liquid paper container for storing liquid, wherein the inner side where the paper end face is exposed is edge-protected, and the outer paper end face where the paper end face is exposed is covered with a thermoplastic resin.   The liquid paper container according to claim 1, wherein the thermoplastic resin is a hot melt resin.   In a method for manufacturing a paper container for storing liquid, the inner side where the paper end surface is exposed is edge protected, and after forming into a container shape, the outer paper end surface where the paper end surface is exposed is covered with a thermoplastic resin Container manufacturing method.