JP2015074479A - Paper container and production method of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tray-shaped or cup-shaped paper container which can be produced with comparatively simple equipment in spite of having a structure that the end face of paper is not at all exposed at the inner and outer surfaces of the container and enabling retort sterilization and to provide a production method of the same.SOLUTION: A paper container comprises: a bottom plate (3); a side plate (4) continued to the bottom plate; a paper-made body (7) having an opening wider than the bottom plate; an outer surface layer (8) being made of a thermoplastic resin and covering the outer surface of the paper-made body; and an inner surface layer (9) being made of a thermoplastic resin and covering the inner surface of the paper-made body. The outer surface layer and the inner surface layer are extended from the upper end part of the side plate and thermally bonded and then form the flange part (10) of the container at the peripheral edge of the opening.

Description

  The present invention relates to a paper container, and more particularly to a tray-shaped or cup-shaped paper container in which the front and back surfaces and end surfaces of the paper are protected by a synthetic resin layer and a method for manufacturing the same.

  Tray-shaped or cup-shaped paper containers are often used mainly for temporary use such as selling foods in stores. Since the paper tray used for these uses is not required to have a high degree of storage stability and durability, a cardboard having one synthetic resin film layer provided on the inner surface side of the container, for example, as shown in FIG. Many of them had a simple structure that was simply punched into a blank shape and assembled by attaching tongue pieces (flaps) (6) at the four corners.

  However, with such a structure, not only is there concern about the water tightness of the container, but the end face of the paper is exposed inside the container, so that the content that contains a lot of moisture or oil soaks in from the end face. Water or oil becomes a stain, which is undesirable in appearance. In addition, there is a hygienic problem that paper dust generated during punching may adhere to the inside of the container when stacked.

  Therefore, as shown in FIG. 11, the side plate (4) and the side plate (4) constituting the side surface are connected to each other without being formed as a tongue piece, and are folded outside the container. A structure in which the end face of the paper is not exposed at all is performed inside.

  However, with the structure shown in FIG. 11, there is no risk of water leakage, but in the corner folding part, three sheets of cardboard overlap, so the side walls become thick and the appearance as a container is not only bad. The problem of poor stackability when stacked is caused. Also, the water tightness of the inner surface of the container is good, but even if a film layer is provided on the front and back surfaces of the paper, the paper will be exposed on the end surface of the flange part, so that the entire container is immersed in water. It could not be used for various purposes.

  The method for assembling a paper tray-shaped container described in Patent Document 1 shows another method for ensuring the watertightness of the tray-shaped container. In the method described in Patent Document 1, a film layer is formed on the inner surface side of a pre-assembled tray-like paper container using a vacuum forming method.

  According to the method for assembling a paper tray-like container described in Patent Document 1, the paper tray does not become unnecessarily thick and is not restricted by the shape of the tray, and is connected to the inner surface of the tray. A layer can be formed.

Japanese Patent Laid-Open No. 11-138663

  Even in the tray-like paper container according to the method described in Patent Document 1, the problem of the paper dust still exists. In addition, even if a synthetic resin film layer is provided on the front side of the paper, the paper is exposed on the end face of the flange part, and should be used for applications that involve water treatment on the entire container such as retort sterilization. I could not.

  On the other hand, various methods for protecting all the end surfaces of the paper exposed to the inside and outside of the container have been proposed. However, since the end surface processing must be performed after making a paper tray blank, the process is very complicated. In addition, since it takes a lot of labor to change the equipment when changing the container shape, it is not suitable for practical use except when a large number of standard-shaped containers are continuously produced.

  The problem to be solved by the present invention has a structure in which the end face of the paper is not exposed at all on the inner and outer surfaces of the container, and can be retort sterilized, but can be manufactured with a relatively simple facility. A cup-shaped paper container and a manufacturing method thereof are proposed.

As means for solving the above problems, the invention according to claim 1 is a paper-made paper having a bottom plate and a side plate connected to the bottom plate, and having an opening wider than the bottom plate. A main body, a thermoplastic resin outer surface layer covering the outer surface of the paper main body, and a thermoplastic resin inner surface layer covering the inner surface of the paper main body, the outer surface layer and the inner surface layer being The paper container is characterized in that it extends from the upper end of the side plate and is heat-sealed to form a flange portion of the container at the periphery of the opening.

  The paper container according to the present invention has a thermoplastic resin layer on the outer surface and the inner surface of the paper body, and the inner and outer surface thermoplastic resin layers extend from the opening and are heat-sealed. The paper layer is not exposed at all. For this reason, it can use also for the use etc. with a retort sterilization process which water takes on the front and back of a paper container.

  According to a second aspect of the present invention, there is provided a paper having a bottom plate, a side plate connected to the bottom plate, a paper flange portion connected to the side plate, and an opening wider than the bottom plate. An outer surface layer made of a thermoplastic resin that covers the outer surface of the paper body, and an inner surface layer made of a thermoplastic resin that covers the inner surface of the paper body, and the outer surface layer and the inner surface layer Is a paper container that extends from the front end of the paper flange part and is heat-sealed to form a flange part of the container together with the paper flange part at the periphery of the opening.

  The invention according to claim 3 is characterized in that the outer surface layer and the inner surface layer made of the thermoplastic resin are heat-sealed to the paper body. It is a container.

  The invention according to claim 4 is characterized in that an air layer is formed between the paper main body and the outer surface layer and / or between the paper main body and the inner surface layer. The paper container according to claim 1 or 2.

  Further, in the invention according to claim 5, the outer surface layer and / or the inner surface layer made of the thermoplastic resin is partially heat-sealed to the paper body, and is heat-sealed. 3. The paper container according to claim 1, wherein an air layer is formed between the unexposed portion and the paper main body. 4.

  The invention according to claim 6 is the paper container according to any one of claims 1 to 5, wherein the paper body is made of corrugated paper.

  The invention according to claim 7 is characterized in that a metal plate is inserted between the bottom surface plate and the outer surface layer or between the bottom surface plate and the inner surface layer. It is a paper container given in any 1 paragraph.

Moreover, invention of Claim 8 is a manufacturing method of the paper container of any one of Claims 1-7 including the following processes. That is, a step of forming a paper body having at least a bottom plate and a side plate connected to the bottom plate and having an opening wider than the bottom plate. A step of heating the thermoplastic resin sheet to form the paper body into a shape that can be accommodated, thereby creating the outer surface layer. A step of heating the thermoplastic resin sheet to form a shape that can be stored in the paper main body, thereby forming the inner surface layer. A method for manufacturing a paper container, comprising: a step of forming a flange portion of a container by placing three layers of an outer surface layer, a paper main body, and an inner surface layer on each other in a mold. It is.

  Moreover, invention of Claim 9 is a manufacturing method of the paper container of any one of Claims 1-7 characterized by including the following processes. That is, a step of forming a paper body having at least a bottom plate and a side plate connected to the bottom plate and having an opening wider than the bottom plate. An outer surface layer configured to heat the one thermoplastic resin sheet to store the paper main body, and an inner surface layer configured to be stored in the paper main body, the orientation of the top and bottom being reversed. A process of forming a set as a set. The paper body is placed on the outer surface layer, and the inner surface layer formed on the paper body is folded back so that the outer surface layer, the paper body, and the inner surface layer are superposed on each other. The method of manufacturing a paper container includes the steps of forming the flange portion of the container.

  According to a tenth aspect of the present invention, in the step of forming the flange portion of the container by superposing the three layers of the outer surface layer, the paper body, and the inner surface layer and placing them in a mold, The method for producing a paper container according to claim 8 or 9, wherein the three layers are heat-sealed over the entire surface or partly at the same time as forming the portion.

  A paper container according to the present invention includes a bottom plate and a side plate connected to the bottom plate, and covers a paper body having an opening wider than the bottom plate, and an outer surface of the paper body. Since it has an outer surface layer made of thermoplastic resin and an inner surface layer made of thermoplastic resin that covers the inner surface of the paper main body, the outer surface and inner surface of the paper main body are covered with the thermoplastic resin layer, and The outer surface layer and the inner surface layer extend from the upper end portion of the side plate and are heat-sealed to form a flange portion of the container at the periphery of the opening portion, so that the end surface of the paper is not exposed at all. ing.

  For this reason, the packaging body that contains the contents and heat-sealed the lid to the flange portion can be given suitability for applications such as retort sterilization treatment or hot water immersion treatment where the whole is immersed in water. Is possible.

  According to a second aspect of the present invention, the paper body has a bottom plate, a side plate connected to the bottom plate, a paper flange portion connected to the side plate, and an outer surface layer and an inner surface layer. And extending from the front end portion of the paper flange portion and heat-sealing, and forming the flange portion of the container together with the paper flange portion on the periphery of the opening, the same effect as the invention of claim 1 is obtained. In addition to having the effect, the strength of the flange portion of the container is enhanced.

  When the outer surface layer and the inner surface layer made of the thermoplastic resin are heat-sealed to the paper body as in the invention described in claim 3, since the entire paper container is integrated, a thin material is used. Even if it is used, it tends to exhibit rigidity and strength as a container.

  Further, as in the invention according to claim 4, when an air layer is formed between the paper main body and the outer surface layer and / or between the paper main body and the inner surface layer, the heat insulating property is reduced. Since it is used, it has the advantage that it is difficult to cool when used for applications such as pouring hot water and cooking, and it is not hot when the container is held by hand.

As in the invention described in claim 5, the outer surface layer and / or the inner surface layer made of thermoplastic resin are partially heat-sealed to the paper body and are not heat-sealed. In the case where an air layer is formed between the portion and the paper body, it is possible to achieve both heat insulation and rigidity of the container by appropriately designing the pattern of the fused portion.

  When the paper main body is made of corrugated paper as in the invention described in claim 6, it can be a paper container having both heat insulation and rigidity.

  When a metal plate is inserted between the bottom surface plate and the outer surface layer or between the bottom surface plate and the inner surface layer as in the invention described in claim 7, an electromagnetic induction heating type cooking utensil is used. The paper container can directly heat cook the contents.

  According to the invention described in claim 8, since the paper main body, the outer surface layer, and the inner surface layer are separately formed and integrated by superimposing the three layers, each material configuration can be independently selected. . For this reason, it is possible to easily select a material configuration most suitable for the application.

In addition, since each process is a relatively simple process, the capital investment is small, and the setup can be easily changed when the shape of the paper container is changed.

  According to the ninth aspect of the invention, since the outer surface layer and the inner surface layer can be molded simultaneously from a single thermoplastic resin sheet, the number of steps is reduced and the production efficiency is good.

  According to the invention described in claim 10, in the step of forming the flange portion of the container by placing the outer surface layer, the paper body, and the inner surface layer on top of each other and placing them in the mold. Simultaneously with the formation of the flange portion, the three layers are heat-sealed over the entire surface or partially, so that the production efficiency is increased as compared with the case of dividing the process.

FIG. 1 is a perspective view showing an embodiment of a paper container according to the present invention. FIG. 2 is a schematic cross-sectional view showing the A-A ′ cross section of the paper container shown in FIG. 1. FIG. 3 is a schematic sectional view showing an embodiment of a paper container according to claim 2 of the present invention. FIG. 4 is a schematic cross-sectional view showing an embodiment of a paper container according to claim 4 of the present invention. FIG. 5 is a schematic sectional view showing an embodiment of a paper container according to claim 5 of the present invention. FIG. 6 is a schematic cross-sectional view showing an embodiment of a paper container according to claim 6 of the present invention. FIG. 7 is a schematic cross-sectional view showing an embodiment of a paper container according to claim 7 of the present invention. FIG. 8 is an explanatory view showing a paper container manufacturing method according to claim 8 of the present invention. FIG. 9 is an explanatory view showing a paper container manufacturing method according to claim 9 of the present invention. FIG. 10 is a blank view showing an example of a conventional paper container. FIG. 11 is a blank view showing another example of a conventional paper container.

  Hereinafter, a paper container and a manufacturing method thereof according to the present invention will be described in detail with reference to the drawings. FIG. 1 is a perspective view showing an embodiment of a paper container according to the present invention. FIG. 2 is a schematic cross-sectional view showing the A-A ′ cross section of the paper container shown in FIG. 1.

  The paper container (1) according to the present invention has a bottom plate (3) and a side plate (4) connected to the bottom plate (3), and has an opening wider than the bottom plate (3). A paper main body (7), a thermoplastic resin outer surface layer (8) covering the outer surface of the paper main body (7), and a thermoplastic resin inner surface layer covering the inner surface of the paper main body (7) The outer surface layer (8) and the inner surface layer (9) are extended from the upper end portion of the side plate (4) and thermally fused, and the flange portion (10 ).

  In a paper container (1) according to the present invention, a paper body (7) is covered with an outer surface layer (8) and an inner surface layer (9) made of a thermoplastic resin, and the outer surface layer and the inner surface layer are on the side. The paper is not exposed to the outside because it extends from the upper end of the face plate and is heat-sealed. Therefore, the paper container (1) according to the present invention can be used for applications where the entire container is splashed with water. For example, although not shown, after the contents are stored, a synthetic resin lid is heat-sealed on the flange portion (10) of the container, and then subjected to retort sterilization treatment or hot water immersion treatment, which can be stored for a long time. Container.

  The paper body (7) has at least a bottom plate (3) and a side plate (4) connected to the bottom plate (3), and a tray having an opening wider than the bottom plate (3). It has a shape or a cup shape. The paper main body (7) may have a paper flange portion (5) connected to the side plate (4) as shown in FIG. In this case, the outer surface layer (8) and the inner surface layer (9) are extended from the front end portion of the paper flange portion (5) and heat-sealed, and the container together with the paper flange portion (5) at the periphery of the opening portion. The flange portion (10) is formed.

  Since the paper body (7) has the paper flange portion (5), the rigidity of the flange portion (10) of the container is increased, so that the thickness of the outer surface layer and the inner surface layer can be reduced.

  The paper body (7) and the outer surface layer (8), or the paper body (7) and the inner surface layer (9) may be in close contact with each other or may be in close contact with each other. It is good, and it does not need to adhere at all.

  When the entire surface is in close contact, the entire paper container is solid and highly rigid, so that the thickness of each material can be reduced. On the other hand, when there is no close contact, a certain degree of rigidity is required for each layer, and thus a corresponding thickness is required.

  FIG. 4 is a schematic sectional view showing an embodiment of a paper container according to claim 4 of the present invention. The paper container (1) shown in FIG. 4 has an air layer (11) between the paper main body (7) and the outer surface layer (8) and between the paper main body (7) and the inner surface layer (9). Is formed.

  The presence of the air layer (11) increases the heat insulation of the paper container (1), making it difficult to cool the contents and has the advantage of not being hot when held by hand. The air layer (11) may be partially formed as shown in FIG. In this example, the inner surface layer (9) is formed with irregularities in advance, and the paper body (7) and the inner surface layer (9) are partially heat-sealed and are not heat-sealed. An air layer (11) is formed.

In the example of FIG. 5, the air layer is formed only on the inner surface side of the paper container, but it may be formed on the outer surface side or on both surfaces. By taking such a structure, the heat insulation and rigidity of the container can be well balanced.

  FIG. 6 is a schematic cross-sectional view showing an embodiment of a paper container (1) according to claim 6 of the present invention. In the example shown in FIG. 6, the paper body (7) is made of corrugated paper. Corrugated paper contains an air layer inside, and therefore has high heat insulation and high rigidity.

  FIG. 7 is a schematic sectional view showing an embodiment of a paper container (1) according to claim 7 of the present invention. In the example shown in FIG. 7, the metal plate (12) is inserted between the bottom plate (3) and the inner surface layer (9). The paper container (1) shown in FIG. 7 can be placed on an induction heating type cooking utensil and the contents can be cooked directly. The insertion position of the metal plate (12) may be between the bottom plate (3) and the outer surface layer (8). As a material of the metal plate (12), a thin plate or foil made of soft iron that can be used in common with a general induction heating cooker is suitable.

  There is no restriction | limiting in particular as a material of the paper-made main body (7) used for the paper container (1) based on this invention, Various paper can be used. For example, paperboard such as corrugated cardboard, Manila cardboard, white ball, chip ball, double-sided card paper, back white cardboard, ivory paper, carton base paper, cup base paper, and the like can be used.

  As a feature of the paper container (1) according to the present invention, since the paper main body (7) is completely covered by the outer surface layer (8) and the inner surface layer (9), it can be used even in low quality paper that is not normally used. It has the advantage of being able to. When porous paper with low density is used, the paper container (1) has good heat insulation properties because it contains a lot of air inside the paper.

  As the material for the outer surface layer (8) and the inner surface layer (9), a thermoformable sheet-like material can be used. The sheet-like material may be a single layer or a laminate composed of a plurality of layers. Materials used for the sheet-like material include low density polyethylene resin (LDPE), high density polyethylene resin (HDPE), linear low density polyethylene resin (LLDPE), polypropylene resin (PP), polyolefins such as polyolefin elastomers Resin, polyethylene terephthalate resin (PET), amorphous polyethylene terephthalate resin (A-PET), ethylene-vinyl acetate copolymer resin (EVA), ionomer resin, polybutene resin, polyacrylonitrile resin, polyamide resin ( Ny), polystyrene resin (PS), polyvinyl chloride resin (PVC), polyvinylidene chloride resin (PVDC), and the like. Films made of these materials can be used in a single layer or in a suitable combination as a laminate.

  The thickness of the outer surface layer (8) and the inner surface layer (9) depends on the material and shape, but from the viewpoint of moldability and handling suitability, it is 0.05 mm or more and 1 mm or less, preferably 0.1 mm or more, 0.5 mm or less.

  Next, the manufacturing method of the paper container based on this invention is demonstrated. FIG. 8 is an explanatory view showing a paper container manufacturing method according to claim 8 of the present invention. FIG. 8A shows a blank (2) of a paper body (7). The blank (2) is formed using a normal box making machine to produce a paper body (7) as shown in FIG. 8 (b).

  On the other hand, as shown in FIGS. 8C and 8D, after setting the thermoplastic resin sheet (16) on a molding machine and heating with a heating device (15), the outer surface layer mold (13) An outer surface layer (8) having a shape capable of accommodating a paper main body (7) is formed. The figure shows a general vacuum forming apparatus, but the forming method may be a vacuum / pressure forming method or a forming method using male and female dies.

Similarly, as shown in FIGS. 8 (e) and 8 (f), an inner surface layer (9) having a shape that can be accommodated in a paper body (7) is formed by the inner surface layer forming die (14). Next, as shown in FIG. 8 (g), the outer surface layer (8), the paper body (7), and the inner surface layer (9) are stacked to form a heat welding type (female type) (17) and heat. The flange part of a container is shape | molded by inserting between welding type | molds (male type | mold) (18), and pressing and welding.

  The three layers may be thermally welded entirely or partially at the same time as the flange portion of the container is formed. The molding method may be thermocompression bonding using a heating mold, but an ultrasonic welding method using ultrasonic waves can also be used.

  The paper container (1) of FIG. 8 (h) is obtained by trimming the flange portion of the finally formed container.

  FIG. 9 is an explanatory view showing a paper container manufacturing method according to claim 9 of the present invention. 9A and 9B for creating the paper main body 7 are the same, but in this method, as shown in FIGS. 9C and 9D, one sheet The thermoplastic resin sheet (16) is heated and stored in an outer surface layer (8) having a shape capable of storing a paper body (7), and in a paper body (7) in which the direction of the top and bottom is reversed. The difference is that the inner surface layer (9) having a possible shape is simultaneously molded as a set.

  Next, as shown in FIG. 9 (e), a paper main body (7) is placed on the outer surface layer (8), and the inner surface layer (9) molded thereon is folded back to thereby form the outer surface. Three layers of a layer (8), a paper body (7), and an inner surface layer (9) are stacked and placed in a mold to form a flange portion of the container.

  The three layers may be thermally welded entirely or partially at the same time as the flange portion of the container is formed. The molding method may be thermocompression bonding using a heating mold, but an ultrasonic welding method using ultrasonic waves can also be used.

  The paper container (1) finally obtained in FIG. 9 (f) is the same as that obtained by the method shown in FIG. 8, but in this method, the outer surface layer (8) and the inner surface layer (9) are simultaneously formed. Therefore, there is an advantage that the number of processes is reduced.

  On the other hand, in the method shown in FIG. 8, the layer configuration of the outer surface layer (8) and the inner surface layer (9) can be set independently, whereas in the method shown in FIG. 9, the outer surface layer (8) and the inner surface layer are configured. (9) is the same material.

  Both the method shown in FIG. 8 and the method shown in FIG. 9 can be realized by a combination of known relatively simple equipments, and can be easily replaced by changing the shape of the paper container.

DESCRIPTION OF SYMBOLS 1 ... Paper container 2 ... Blank 3 ... Bottom board 4 ... Side board 5 ... Paper flange part 6 ... Flap 7 ... Paper-made main body 8 ... Outer surface layer 9 ... Inner layer 10 ... Flange portion 11 ... Air layer 12 ... Metal plate 13 ... Outer surface layer forming die 14 ... Inner layer forming die 15 ... Heating device 16 ...・ Thermoplastic resin sheet 17 ... heat fusion type (female type)
18 ... Thermal fusion type (male type)

Claims (10)

  A paper body having a bottom plate and a side plate connected to the bottom plate and having an opening wider than the bottom plate; and an outer surface layer made of a thermoplastic resin covering the outer surface of the paper body. An inner surface layer made of a thermoplastic resin that covers the inner surface of the paper body, and the outer surface layer and the inner surface layer are extended from the upper end portion of the side plate and thermally fused, and the periphery of the opening A paper container characterized in that a flange portion of the container is formed.   A bottom plate, a side plate connected to the bottom plate, a paper flange portion connected to the side plate, a paper body having an opening wider than the bottom plate, and the paper body It has an outer surface layer made of a thermoplastic resin that covers the outer surface, and an inner surface layer made of a thermoplastic resin that covers the inner surface of the paper body, and the outer surface layer and the inner surface layer are formed from the tip of the paper flange portion. A paper container which is extended and heat-sealed to form a flange portion of the container together with the paper flange portion on the periphery of the opening.   3. The paper container according to claim 1, wherein the outer surface layer and the inner surface layer made of the thermoplastic resin are thermally fused to the paper main body.   The paper container according to claim 1, wherein an air layer is formed between the paper main body and the outer surface layer and / or between the paper main body and the inner surface layer. .   The outer surface layer and the inner surface layer made of the thermoplastic resin, or any one of them is partially heat-sealed to the paper body, and the portion not heat-sealed is the paper body. The paper container according to claim 1, wherein an air layer is formed between the two.   The paper container according to any one of claims 1 to 5, wherein the paper main body is made of cardboard paper.   The paper container according to any one of claims 1 to 6, wherein a metal plate is inserted between the bottom plate and the outer surface layer, or between the bottom plate and the inner surface layer. The method for producing a paper container according to claim 1, comprising the following steps.
A step of forming a paper body having at least a bottom plate and a side plate connected to the bottom plate and having an opening wider than the bottom plate.
A step of heating the thermoplastic resin sheet to form the paper body into a shape that can be accommodated, thereby creating the outer surface layer.
A step of heating the thermoplastic resin sheet to form a shape that can be stored in the paper main body, thereby forming the inner surface layer.
A process of forming a flange portion of a container by superposing three layers of an outer surface layer, a paper body, and an inner surface layer and placing them in a mold. The method for producing a paper container according to claim 1, comprising the following steps.
A step of forming a paper body having at least a bottom plate and a side plate connected to the bottom plate and having an opening wider than the bottom plate.
An outer surface layer configured to heat the one thermoplastic resin sheet to store the paper main body, and an inner surface layer configured to be stored in the paper main body, the orientation of the top and bottom being reversed. A process of forming a set as a set.
The paper body is placed on the outer surface layer, and the inner surface layer formed on the paper body is folded back so that the outer surface layer, the paper body, and the inner surface layer are superposed on each other. The process which mounts in and forms the flange part of a container.   In the step of forming the flange portion of the container by superimposing the outer surface layer, the paper body, and the inner surface layer on the three layers, and forming the flange portion of the container, The method for producing a paper container according to claim 8 or 9, wherein heat fusion is performed over a part or part of the paper container.