JPH0470440B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to containers such as paper boxes whose side walls are substantially upright with respect to the bottom, particularly paper products made by forming paper into a shape that substantially corresponds to the container. It concerns a container and its manufacturing method.

[Prior Art] Attempts have been made to integrally form paper containers such as paper boxes, especially three-dimensional paper containers whose side walls are substantially upright relative to the bottom, by papermaking, and the present inventors have (2013) also proposed that paper should be made into a shape that approximately corresponds to the final product using a paper mold that corresponds to the shape of the container, and then a certain amount of moisture would be removed and the product would be completely dried by press molding and then formed into the final shape ( (Special Application No. 1983-57575).

[Problems to be Solved by the Invention] In the method proposed above, the fibrous paper stock in the paper stock solution is suctioned and adhered to the papermaking mesh of one papermaking mold, and after papermaking, it is dehydrated and molded. It is something.

In this case, the side of the adhered stock layer that is attached to the papermaking net becomes relatively flat and is finished quite beautifully by press forming after papermaking, but on the side opposite to the attached side, the fiber content is They become intertwined with each other and harden into a core-like state, and the surface of the paper stock layer becomes uneven, like "welts", over the entire surface. These irregularities become larger as the thickness of the deposited stock layer increases. When these irregularities become large, even if the paper is pressed and molded very strongly during the press stage after papermaking, the unevenness marks become wrinkle-like because paper is a fibrous material that does not flow like resin. This creates patterns and stains on the surface, which greatly impairs the beauty of the product and makes it look less luxurious. Furthermore, attaching other thin paper or the like to the surface in order to cover this requires time and effort in manufacturing and increases costs.

Furthermore, if the container is made using a convex paper mesh as shown in FIG. On the other hand, the fibers tend to be difficult to collect at the corner 6' which is a continuous curved part with the side wall 1' around the bottom of the container, that is, at the boundary between the end surface and the side surface of the convex part. Therefore, although the fiber density at the container opening 5' increases, the fiber density decreases at the corner 6' around the container bottom 2', making it impossible to obtain the intended inner thickness, resulting in weakened strength and stiffness. This resulted in the occurrence of cuts, which caused problems in practical application.

Furthermore, when papermaking is carried out using a concave papermaking net as shown in FIG. It tends to be difficult to gather. Therefore, the corner 6' around the bottom of the container has a high fiber density and has a relatively firm finish, but the container opening 6' has a low fiber density, resulting in a thin and stiff finish.

Therefore, no matter which type of papermaking mesh is used, trial and error is required in various papermaking techniques to make the paper quality uniform, and it is also necessary to adjust the shape of the papermaking mesh and the suction pressure. .

In view of the above, the present invention provides a paper container formed by paper making and molding so that the side wall is substantially upright with respect to the bottom, in which a particularly thick inner paper layer and an outer paper layer are separated. By making paper and laminating it, it has the necessary and sufficient thickness for use as paper boxes, etc., and has a beautiful appearance without wrinkles or shading caused by high or low fiber density on either the inside or outside surfaces. In addition, the present invention provides a paper container that can uniformize the fiber density at the opening and bent portions and has sufficient shape-retaining strength as a whole, and also provides a manufacturing method that allows the paper container to be manufactured efficiently and reliably. A method is also provided.

[Means for Solving the Problems] In order to solve the above problems, the present invention provides a paper container formed by paper making and molding so that the side walls are substantially upright with respect to the bottom. The inner paper layer was made with the surface to be attached to the paper-making mesh, and the outer paper layer was made with the outer surface to the surface to be attached to the paper-making mesh, and the surfaces opposite to the surfaces to be attached to the paper-making mesh were It is characterized by being formed by fitting and bonding so as to face each other and molding them.

The second aspect of the present invention relates to a method for manufacturing the above-mentioned paper container, in which, in the papermaking process, an inner paper mold having a convex paper mesh having a shape substantially corresponding to the inner surface of the container to be manufactured; Using an outside paper mold having a concave paper mesh having a shape that roughly corresponds to the outer surface of the container, both of the paper molds are immersed in a paper stock solution and the paper stock is attached to the surface of each paper mesh using suction means. In the dehydration process after papermaking, the paper stock layer adhering to the surface of the convex papermaking mesh and the paper adhering to the surface of the concave papermaking mesh are separated by the fitting of the two papermaking dies. The material layer is brought together with the surfaces opposite to the surfaces to be attached to the paper making mesh facing each other, and further, after a certain amount of moisture has been removed, the material layer is removed from the mold, press-formed, and dried. shall be.

[Function] According to the method of the present invention described above, each paper making mold is made by using an inner making mold having a convex paper making mesh and an outer making mold having a concave paper making mesh approximately corresponding to the outer surface of the container. The paper material is suctioned and adhered to the surface of the paper making net, and is made into layers. After this paper making, the two paper material layers adhering to the surface of each paper making net are combined and formed, so that the paper stock layer which becomes the inner paper layer and the outer paper material layer are formed. The thickness of the stock layer serving as the paper layer may be, for example, approximately half the thickness of the container. Therefore, the surfaces of both paper stock layers attached to the convex papermaking mesh and the concave papermaking mesh, respectively, have less unevenness due to fiber lumps and density differences, and in other words, the thickness of the container can be adhered to one papermaking mesh. The surface irregularities are smaller than when paper is made by hand. In addition, by fitting these two stock layers together and bringing the surfaces opposite to the surfaces that are attached to the papermaking net into contact with each other, the unevenness on the surface of the paper stock layer is contained within the thick wall. Therefore, both the inner and outer surfaces of the container become molded surfaces from the surfaces attached to the papermaking net, and wrinkle-like patterns due to differences in fiber density do not occur. A paper container with a flat and beautiful surface can be obtained.

In addition, the paper stock layer, which becomes the inner paper layer that adheres to the convex paper mesh of the inner papermaking mold, becomes thicker at the openings as more fibers gather, but it becomes thinner at the corners around the bottom where fibers are less likely to gather. On the contrary, the paper stock layer, which is the outer paper layer that adheres to the concave paper mesh of the outer papermaking mold, is thin because it is difficult for fibers to collect at the openings, and there is a large amount of fibers at the corners around the bottom. It tends to gather and become thick. Therefore, in order to combine and press-form these two paper stock layers, the defects of both paper stock layers are compensated for, and the fiber density is insufficient even in the corners and openings around the bottom. It is possible to maintain substantially uniform fiber density and thickness as a whole without becoming excessive.

Furthermore, after the above-mentioned two paper stock layers are joined together, suction dehydration is performed on one of the paper mold sides, so that the fibers of both paper stock layers become intertwined, and together with the fact that the fibers are tightened by press molding, they are firmly attached. Unify.

Although the paper container of the present invention obtained as described above is made of paper, it not only has no folds or adhesive parts, but also has a convex paper mesh on the inner surface. The inner paper layer was made with the surface to be attached to the paper-making mesh, and the outer paper layer was made with the outer surface to the surface to be attached to the paper-making mesh. Because they are fitted and bonded so that they are in contact with each other and molded, both the inner and outer surfaces are relatively flat, and the molding surface is from the surface attached to the papermaking net, and there are no irregularities or wrinkle-like patterns due to the high or low fiber density. The paper has a flat and beautiful surface with no blemishes, and even in the corners and openings around the bottom, the fiber density is uniform without too much or too little, and the necessary and sufficient thickness is ensured, giving it a moderate waist. It retains strength and shape retention.

[Example] Hereinafter, embodiments of the present invention will be described based on the drawings.

Figures 1 and 2 show a paper container A according to the present invention which is formed into a final shape by paper making so that the four circumferential side walls 1 are substantially upright with respect to the bottom 2, and the inner surface is placed on a paper making net. Inner paper layer 3 made with paper facing side to which it is attached
and an outer paper layer 4, which has been made with the outer surface facing the paper-making mold, are bonded together and molded.

Next, a method for manufacturing the paper container A as described above will be described.

As shown in FIGS. 3 and 4, the paper-making device includes an inner paper mold 10 having a convex papermaking mesh 11 formed to approximately correspond to the inner surface of the container A to be manufactured, and an inner paper making mold 10 that approximately corresponds to the outer surface of the container. An outside papermaking die 20 having a concave papermaking net 21 formed in such a manner as to be used is used.

The convex papermaking net 11 of the inside papermaking mold 10 and the concave papermaking net 21 of the outside papermaking mold 20 are both made of relatively fine mesh nets, and the inside thereof is usually made of copper, brass or other metal. A mold member (not shown) having a large number of suction holes is provided on substantially the entire surface to hold it in a predetermined shape. In addition, in consideration of press forming after papermaking, the convex papermaking net 11 is usually slightly smaller than the inner dimension of the container, and the concave papermaking net 2
1 is formed to be slightly larger than the outer dimensions of the container.

These inside mold 10 and outside mold 2
0 has a hollow interior with paper-making nets 11 and 21 fixed to paper-making net fixing frames 12 and 22, respectively, as shown in the drawings. Then, suction pipes 13 are attached to the paper-making net fixing frames 12 and 22, respectively.
and 23 are connected to each other, and are also connected to suction means (not shown) such as a pump through the suction pipes 13 and 23, whereby the paper stock solution a supplied to the paper stock solution tank 30 is transferred to each papermaking network. 11,2
It is designed so that suction can be carried out at part 1.
Furthermore, the two papering dies 10 and 20 are respectively provided so as to be movable up and down with respect to the paper stock solution tank 30 by appropriate means, and the paper stock solution a in the paper stock solution tank 30 is
It is provided so that it can be freely immersed in the water. Fig. 3 shows the state in which both the papering molds 10 and 20 are taken out upwards, and Fig. 4 shows the state in which only the outer papering mold 20 is removed from the paper stock solution a.
It shows the state immersed in.

It is particularly advantageous for the two paper dies 10 and 20 to be arranged in vertically corresponding positions as in the illustrated embodiment for the purpose of joining together after suction papermaking.

If the stock solution a in the paper stock solution tank 30 is configured to be circulated and supplied, the paper stock solution a in the paper stock solution tank 30 will be agitated and the fibers will harden or become uneven. It is preferable because it can prevent the above-mentioned problems and paper-making by suction can be performed well. Of course, other stirring means may also be provided.

In order to make and manufacture the paper container A using the above-mentioned paper making apparatus, as shown in FIG.
0 and 20 are lowered in the separated state into the paper stock solution tank 30 and submerged in the paper stock solution a. In this state,
By activating the suction means and sucking the paper stock solution a from the outside of the paper making nets 11 and 21 of the two strainers 10 and 20, the paper stock solution a is forcibly filtered by suction, and the paper stock solution a is separated from each other. It adheres to the surface of the papermaking nets 11 and 21 in a layered manner. The thickness of the adhered paper stock layers a1 and a2 is adjusted by adjusting the paper stock concentration in the paper stock solution, the suction time, etc., and is approximately half the thickness of the container to be manufactured before press forming.
The paper is made to a thickness corresponding to . Therefore, this paper making time is halved compared to the case where the entire wall thickness is paper made.

After papermaking is carried out in this manner, the two paper molds 10 and 20 are lifted up in their separated state and taken out into the air, and in this state the suction action is continued to dehydrate them together with the air (FIG. 6). Although unevenness occurs on the surface of the paper stock layers a1 and a2 that are skived in this way due to the stiffness of the fibers and the difference in density, since the thickness is equivalent to approximately 1/2 of the container wall thickness,
The unevenness is not so large.

During the dewatering step, as shown in FIG. Adhered paper stock layer a1
and the paper stock layer a2 attached to the surface of the concave papermaking net 21.
and the surfaces of both stock layers a1 and a2 are joined together.

Thereafter, the suction action of the outer mold 20 is stopped, and at the same time the inner mold 10 is raised while the suction dewatering action is being performed (FIG. 8). This results in
Not only the paper stock layer a1 but also the paper stock layer a2 attached to the surface of the concave papermaking net 21 is removed by the above-mentioned suction.
The mold is transferred to the inside mold 10 while remaining bonded to the top of the mold 1. Further, in this state, suction dehydration is further continued on the side of the inner skiving mold 10 to perform dehydration. As a result, the fibers of both stock layers a1 and a2 are entangled with each other at the joint.

After a certain amount of moisture has been removed in this way, both stock layers a1 and a2 are separated from the cutting mold 10,
This is heated and press-molded from the inside and outside using a molding device having a predetermined mold, such as the molding device disclosed in Japanese Patent Application No. 62-122279 filed by the present applicant, and is completely dried into the final product shape. Just mold it.

In the paper container A manufactured as described above, the inner paper layer 3 made of the paper stock layer a1 and the outer paper layer 4 made of the paper stock layer a2 are bonded together by fibers entwined with each other and compressed by press molding as described above. , this is paper stock solution a
Combined with the solidification of the glue contained therein, it becomes a strongly bonded and integrated product.

In particular, the paper making nets 11 and 2 of the paper stock layers a1 and a2
Since the surface opposite to the surface to which paper-making nets 11 and 21 are attached is sealed inside the thick wall, unevenness caused by lumps of fibers does not appear on the inner and outer surfaces. A paper container A is obtained which exhibits a flat and beautiful surface without wrinkle-like patterns due to differences in fiber density or the like.

Further, the inner paper layer 3 formed by the paper stock layer a1 attached to the convex papermaking net 11 of the inner papermaking die 10 is formed at the opening 5.
On the other hand, the paper stock layer a2 that adheres to the concave papermaking net 21 of the outer papermaking die 20 tends to become thinner because the fibers are less likely to collect at the corner 6 around the bottom. The outer paper layer 4 tends to become thinner at the opening 5 because it is difficult for the fibers to collect therein, while it tends to become thicker at the corners 6 around the bottom where more fibers collect. As shown in the enlarged view of FIG. 2, by arranging the fibers, the defects of each other are compensated for, and the fiber density is neither insufficient nor excessive in the opening 5 and the corner 6 around the bottom. Therefore, the fiber density and thickness are substantially uniform as a whole, and sufficient stiffness and strength can be obtained.

In addition, in the above embodiment, a case was shown in which the inside papermaking mold 10 and the outside papermaking mold 20 were suction-formed in the same stock solution tank 30, but these papermaking molds 10 and 20 were separated into separate paper stock solutions. It is also possible to carry out suction papermaking in a solution tank and form a bonded structure in the same manner as above.
The inner and outer paper layers 3, using paper stock solutions of different materials,
4 can be easily made different, and it is also easy to make them different colors. For example, if an inexpensive material is used for one of the inner and outer paper layers 3 and 4, such as the inner paper layer, and a high-quality paper material is used for the other, it is possible to increase the commercial value and reduce costs. Further, it is also possible to sandwich other substances in the inner and outer paper layers 3 and 4.

Furthermore, if high-quality thin paper such as Japanese paper is pasted on the surface of the paper stock layer before press forming after papermaking and dehydration, this will integrate the thin paper and eliminate the risk of peeling. , the appearance will be even better.

Further, the container A to be paper-formed may be any container shape consisting of a bottom and a side wall.
For example, the same method as described above can be applied to a container-shaped lid having a top part and a side part. Furthermore, the container A is not limited to a container having a planar quadrilateral shape as shown in the figure, such as a pentagonal shape, other polygonal shape, or a container having a circular shape.
Similarly to the above, this can be carried out by making the paper mold into a shape that substantially corresponds to the shape of the product, and it is also possible to easily make a container with a curved bottom and continuous sides.

[Effects of the Invention] As described above, according to the present invention, a paper container whose side wall is substantially upright with respect to the bottom is produced by separating the particularly thick inner paper layer and outer paper layer. By having a bonded structure, it has the necessary and sufficient thickness for use as a paper box, etc., and the wrinkle pattern and shading due to the high and low fiber density are contained between the inner and outer paper layers and appear on both the inner and outer surfaces. It has a flat and beautiful surface appearance. In addition, the fiber density at the openings and bends is uniform, with just the right amount and no shortage, and has appropriate stiffness and shape-retaining strength, and no cuts occur. Therefore, it is possible to obtain a paper container that has a good appearance and excellent shape retention.

Further, according to the manufacturing method of the present invention, a paper container exhibiting the above-mentioned effects can be easily manufactured and provided efficiently. In particular, since the inner and outer paper layers are bonded together, it is easy to insert other substances between the two paper layers or to change the materials of the two paper layers.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway perspective view showing an embodiment of the present invention, FIG. 2 is an enlarged sectional view taken along the line taken from the front figure,
FIG. 3 is a perspective view of the papermaking apparatus used in the production of the present invention, FIG. 4 is a longitudinal sectional view of the same, FIGS. 5 to 8 are sectional views showing the manufacturing process, and FIG. Cross-sectional view showing the state of papermaking in the case of only
The figure is a cross-sectional view showing the state of papermaking by concave papermaking. A...paper container, 1...side wall, 2...bottom, 3...inner paper layer, 4...outer paper layer, 5...opening, 6...corner around the bottom, 10...inner mold, 11...convex shape Paper making net, 12... paper making net fixing frame, 20... outside making mold,
21...Concave papermaking net, 22...Papermaking net fixing frame, 30...
Paper stock solution tank, a...Paper stock solution, a1, a2...Adhered paper stock layers.

Claims (1)

[Scope of Claims] 1. A paper container made of paper and formed so that the side wall is substantially upright with respect to the bottom, the inner side of which is made of paper with the inner surface facing the convex paper mesh. The paper layer and the outer paper layer, which is made with the outer surface facing the concave paper mesh, are fitted and bonded together so that the surfaces opposite to the surfaces that are bonded to the paper mesh are in contact with each other. A paper container characterized by being formed by molding. 2. In the papermaking process, an inner papermaking mold having a convex paper mesh having a shape that approximately corresponds to the inner surface of the container to be manufactured and an outer papermaking mold having a concave paper mesh having a shape approximately corresponding to the outer surface of the container are used. The two paper-making molds are immersed in a paper stock solution, and the paper stock is applied to the surface of each paper-making net using suction means, and the paper stock is made into a layer of the required thickness. By fitting them together, the paper stock layer attached to the surface of the convex papermaking net and the paper stock layer attached to the surface of the concave papermaking net are brought into contact with the surfaces opposite to the surfaces attached to the papermaking net. 1. A method for manufacturing a paper container, which comprises the steps of: removing the moisture to some extent, removing the water from the mold, press-forming, and drying. 3. A claim characterized in that after the paper stock layer attached to the surface of the convex papermaking net and the paper stock layer attached to the surface of the concave papermaking net are combined, the paper material is suction-dehydrated to one of the papermaking mold sides. 2. The method for manufacturing a paper container according to 2.