JPH05279998A - Cup produced directly by paper making and its production - Google Patents

Abstract

PURPOSE:To produce a deep cup produced directly by paper making, having both the smooth surface and the smooth back surface and excellent in mechanical strength by collecting the pulp component from a pulp stock solution according to the paper making technique. CONSTITUTION:From a pulp stock solution, the pulp component is collected on a cup-shaped papermaking wire 7 and a force piston 9 made of an elastic material is pressed thereto from the upper surface side. Thereby, the pulp raw material collected on the wire 7 is dehydrated and an intermediate 10 of the objective cup is obtained. The resultant intermediate cup 10 is heat-pressed, thus producing the objective cup produced directly by paper making, involving the side wall having >=45 deg. rising angle and having >=15mm depth and >=0.3g/cm<3> density.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a papermaking container and a method for producing the same.

[0002]

2. Description of the Related Art In recent years, foamed synthetic resin materials, papers made into a predetermined shape from pulp raw material liquids, etc. have been used for packaging home electric appliances, precision instruments, foods and the like. .. Of these, those made from pulp are mainly used as containers for packaging small electric products and food such as eggs.

[0003] Conventionally, when a deep-bottomed container is manufactured by a papermaking method, the pulp component in the pulp raw material liquid is simply taken out on a papermaking net formed into a predetermined container shape and dehydrated to form a paper having a predetermined shape. The method of obtaining the container was adopted.

[0004]

However, in the conventional deep-bottomed container manufactured by such a papermaking method, the surface on the side in contact with the papermaking net is relatively smooth,
The surface on the opposite side (upper surface side during container making) is an irregular uneven surface with pulp components still being taken out, and when the paper is made so that this uneven surface becomes the product storage side, There is a drawback that it is difficult to store the product in the obtained container in a stable manner.
The external appearance of the container was poor, and the product value was lowered.

Further, the conventional papermaking container has a drawback that its strength is remarkably lower than that of a plastic container. The present invention has been made in view of the above points and provides a deep-bottomed papermaking container having a smooth surface on both front and back sides, and a method for producing the deep-bottomed papermaking container having excellent strength. The purpose is to

[0006]

[Means for Solving the Problems] That is, the papermaking container of the present invention is formed by extracting a pulp component from a pulp raw material liquid and having a side wall having a rising angle of 45 degrees or more and a predetermined shape having a depth of 15 mm or more. The deep-bottomed papermaking container is characterized in that the surface on the upper surface side during the papermaking is formed smooth and has a density of 0.3 g / cm ³ or more. The papermaking container of the present invention includes a container having at least one convex portion formed at the bottom by papermaking.

Further, according to the method for producing a papermaking container of the present invention, a pulp component is taken out from a pulp raw material liquid on a papermaking net formed into a container shape, and papermaking is carried out on the papermaking net. The upper surface side of the pulp component is pressed by a pressing die made of an elastic material formed into a container shape, and the water in the pulp component taken out on the papermaking net is dehydrated to obtain a papermaking container intermediate, and then This papermaking container intermediate is characterized in that it is pressed under heating by a pressing die having a container shape.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a longitudinal sectional view of an embodiment of the papermaking container of the present invention. As shown in the drawing, the papermaking container 1 of the present invention has a rising angle α of the side wall 2 of 45 degrees or more. There is a deep bottom papermaking container having a depth of 15 mm or more. The papermaking container 1 of the present invention has a density of 0.3 g / cm ³ or more, and has a very high density as compared with the conventional papermaking container.

The papermaking container 1 of the present invention is made by making pulp components from a pulp raw material liquid to form a predetermined shape. As shown in FIG. 1, the bottom portion 3 has a convex portion 4 formed by papermaking. And a concave portion 5 is formed. As shown in the drawing, the convex portion 4 may be formed at only one place of the bottom portion 3, at a plurality of places, or may not be formed at all, but as the container 1 of the present invention, the bottom portion is formed. A container in which the convex portion 4 is formed at one or more places of 3 is suitable. At this time, it is desirable that the height of the convex portion is formed to be approximately 5 mm to the depth of the container.

The container 1 of the present invention has a smooth surface (for example, the outer surface side of the container) which is in contact with the net during the later-described papermaking, and an upper surface which is not in contact with the net during papermaking ( The inner surface of the container) is also smooth. In the present invention, the fact that the inner surface of the container is smooth means that there is no unevenness due to the protrusion of the pulp component extracted on the surface side, and a fine uneven pattern or the like is formed on the surface. It does not exclude things.

The above-described papermaking container 1 of the present invention can be manufactured as follows.

In FIG. 2, reference numeral 6 denotes a papermaking apparatus for the container 1 of the present invention. The apparatus 6 is a netting 7 for papermaking formed in a predetermined shape (in the example of FIG. 2, the outer surface shape of the container to be made into paper).
And a mold (not shown) for holding the net 7, which has an inner shape that substantially matches the outer shape of the net 7, and has a plurality of through holes through which water can permeate the wall surface and the bottom surface thereof, and A supporting frame 8 for supporting the mold and a predetermined shape (in the example of FIG. 2, a shape that substantially matches the inner surface shape of the container to be manufactured)
And a pressing die 9 made of an elastic material.

When the papermaking container 1 of the present invention is manufactured in the above apparatus 6, first, the pulp components in the pulp raw material liquid are taken out onto the papermaking net 7. As a method for extracting pulp components from the pulp raw material liquid, a method for pouring the pulp raw material liquid onto the papermaking net 7 to extract the pulp components on the net, and the entire frame 8 with the net 7 attached to the pulp raw material After immersing in a liquid tank and vacuum sucking from below the net as needed to let a part or most of the water content of the pulp raw material liquid flow out through the net 7, the frame 8 is raised to raise the pulp component in the pulp raw material liquid. There is a method of extracting paper on the net 7.

In the present invention, as the above pulp raw material liquid, a conventionally known pulp raw material liquid, a liquid obtained by adding various additives thereto, or the like is used. It should be noted that there is no problem with the pulp raw material liquid, whether the recycled pulp raw material liquid using recovered paper occupies all the components or a part thereof.

As the papermaking net 7, a material which allows water in the pulp raw material to pass but not the pulp component 9 is used, and the water in the pulp raw material is removed by passing through the papermaking net 7, resulting in papermaking. The pulp component 8 is made on the net 7. The amount of the pulp component 9 to be drawn on the papermaking net 7 can be adjusted by the fiber concentration in the pulp raw material and the vacuum suction time, which is performed as needed when the paper is drawn on the net.

As described above, the paper making net 7 can be used as long as it has a mesh that allows the moisture in the pulp raw material to pass through but does not allow the pulp component 9 to pass therethrough. There is a possibility that the traces of the net will be clearly left on the surface of the net 7 on the side of 1 to deteriorate the appearance, and conversely, if the mesh of the net 7 is too fine, clogging easily occurs,
It is preferable to use one having a mesh of about 15 to 80 mesh.

After the pulp components in the pulp raw material liquid are thus drawn on the papermaking net 7, the paper is pressed by the pressing die 9 from the upper surface side, and the lower surface side of the papermaking net 7 is depressurized. The water in the pulp material that has been scraped off is dehydrated to obtain a papermaking container intermediate 10 having a water content of about 30 to 70%.

As the pressing die 9, an elastic material formed into a predetermined shape is used, and as the elastic material, for example, rubber, elastic synthetic resin, synthetic resin foam or the like can be used. Further, the pressing by the pressing die 9 has an apparent thickness of 1 when the pulp component is taken out on the net.
When it is set to 00, the thickness is preferably about 10 to 40, and when the lower surface side of the papermaking net 7 is depressurized, the depressurization condition is preferably about 700 to 10 mmHg.

Papermaking container intermediate 10 thus obtained
Are then transferred to the hot pressing process. In the hot pressing step, for example, as shown in FIG. 3, the container intermediate 10 is sandwiched and heated by a female mold 11 having an outer surface shape of the papermaking container intermediate 10 and a male mold 12 having an inner surface shape of the papermaking container intermediate 10. Press down. The heating and pressing conditions are preferably a heating temperature of 100 to 250 ° C. and a pressing time of about 5 to 200 seconds. The hot pressing step is not limited to one time, but it is also preferable to perform the heating press step several times. When the heating and pressing process is performed several times, the male mold 12 and the female mold 11 are moved to the later heating and pressing process.
It is preferable that the clearance (gap) between and is gradually decreased. And when the apparent thickness of the final product is 100 when the pulp component is drawn on the net,
It is preferable to perform hot pressing so as to be about 5 to 30. Further, it is possible to form a plurality of fine through holes through which moisture can pass in these molds, and it is also possible to suck the inside of the mold through the through holes.

As described above, first, the upper surface side of the pulp raw material made by the papermaking net 7 is pressed by a pressing die made of an elastic material to dehydrate the water in the pulp raw material so that the intermediate product of the papermaking container is dehydrated. Then, by further hot pressing this papermaking container intermediate, the surface on the upper surface side during papermaking becomes a smooth surface, and the density is 0.3 g / cm ³ , preferably 0.35 to 0.5.
The papermaking container 1 of the present invention having 9 g / cm ³ is obtained.

The present invention will be described in more detail with reference to specific examples.

Example 1 Depth: d = 4.5 cm, Side wall rising angle: α = 85 °
1 of the same shape as shown in FIG. 1 (height of the convex portion 3.
5 cm, width 2.5 cm) were produced by the same equipment as shown in FIG. 4 as the paper making net 7 of the apparatus used
A 0-mesh net was used, and the pressing die 9 was made of silicone rubber. A pulp raw material liquid having a fibrin concentration of 0.5% was used, and the papermaking net 7 was immersed in this pulp raw material liquid for 5 seconds while being attached to the frame 8 via a net holding mold. Next, the net 7 was pulled up from the raw material liquid. The apparent thickness of the pulp component removed at this time was about 4.5 mm. Then, while pressing the upper surface side of the pulp component cut off on the net 7 by the pressing die 9, the lower surface side of the net 7 is 200 mmHg.
The pressure was reduced to. The thickness of this intermediate was about 3 mm.

Papermaking container intermediate 10 thus obtained
Was sandwiched between a female mold 11 and a male mold 12 similar to those shown in FIG. 3 and hot-pressed for 10 seconds. At this time, the temperature of the female mold 11 and the male mold 12 was 170 ° C., and the thickness after pressing was about 2 mm. Further, the same hot-pressing step was continuously performed in two steps. The thickness of the papermaking container after pressing is about 1.2 after the second pressing.
mm, and about 0.7 mm after the third press. The papermaking container thus obtained had a density of 0.4 g / cm ³ , and was excellent in smoothness on the inner and outer surfaces of the container. Next, when an iron plate having a weight of 15 kg was gently placed on the upper surface of the container so as to cover the entire surface of the container opening, the container was able to withstand this weight sufficiently.

Comparative Example 1 A papermaking container was obtained in the same manner as in Example 1 except that hot pressing was not performed. This container was excellent in smoothness on the surface pressed by the silicone rubber mold, but the trace of the net was clearly left on the surface in contact with the net. The density of the obtained container was 0.28 g / cm ³ , and Example 1 was placed on the upper surface of the container.
When an iron plate with a weight of 15 kg was placed gently in the same manner as in, the container was crushed, and the strength was found to be inferior to that of the container of Example 1.

[0026]

As described above, the papermaking container of the present invention is a deep-bottomed container having a side wall rising angle of 45 degrees or more and a depth of 15 mm or more, and both sides of the container are formed smooth. Therefore, the product can be stably stored in the container and the appearance of the container is excellent, and the product has a high commercial value. In addition, the density of the container of the present invention is 0.3 g / cm ³ or more, which is higher than that of the conventional papermaking container, and therefore is excellent in mechanical strength such as bending strength and rigidity.

Further, according to the manufacturing method of the present invention, it is possible to manufacture a papermaking container having a smooth inner and outer surface as described above and having a high density.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing an example of a papermaking container of the present invention.

FIG. 2 is a vertical sectional view showing one step in the method for producing a papermaking container of the present invention.

FIG. 3 is a vertical cross-sectional view showing another step in the method for manufacturing a papermaking container of the present invention.

[Explanation of symbols]

 1 Papermaking container 2 Side wall 3 Bottom part 4 Convex part 7 Papermaking net 9 Pressing type 10 Papermaking container intermediate 11 Female type 12 Male type

Claims (3)

[Claims] 1. A pulp component is extracted from a pulp raw material liquid and has a sidewall having a rising angle of 45 degrees or more and a depth of 1
A deep-bottomed papermaking container having a predetermined shape of 5 mm or more, characterized in that the container has a smooth upper surface during papermaking and has a density of 0.3 g / cm ³ or more. Papermaking container to be. 2. The papermaking container according to claim 1, which has at least one convex portion formed by papermaking on the bottom of the container. 3. A papermaking net formed into a container shape is used to make pulp components from the pulp raw material liquid, and the upper surface side of the pulp components made to the papermaking net is
Pressed by a pressing die made of an elastic material formed into a container shape to dehydrate the water in the pulp component taken out on the papermaking net to obtain a papermaking container intermediate, and then this papermaking container intermediate A method for producing a papermaking container, comprising pressing under heating with a press die having a shape.