JPH11342550A - Paper-making mold for pulp mold molding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable manufacturing of moldings at a low cost and simple change of molds to be performed by providing a paper-marking part and a manifold part, which have plural communicating holes and are changeable in accordance with the kind of moldings. SOLUTION: This paper-making mold comprises a paper-making part 1 with a cavity part 3 and a manifold part 6. A hollow chamber encircled by the back part of the paper-making part 1 and the side wall 7 and the nozzle part side wall 8 of the manifold part 6 is formed by fitting the manifold part 6 into the back part of the cavity part 3. In addition, plural communicating holes 12 which communicate with the hollow chamber from the cavity part 3 are formed in the block 5 of the paper-making part 1. Further, the paper-making part 1 has a hook part 10, on which a ring part 11 provided on the manifold part 6 is hooked to lock the paper-making part 1 into the manifold part 6 in such a manner that these two parts 1, 6 are changeable. When the products are switched for manufacturing, only the paper-making part 1 is changed. Thus it is possible to manufacture the product at a low cost and at the same time, change the mold easily.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold for producing a pulp molded product used as a packaging member such as a container or a cushion material.

[0002]

2. Description of the Related Art Plastic containers have various problems in disposal. Therefore, a pulp mold container formed by a pulp mold method is attracting attention.

[0003] A papermaking mold used in the manufacture of a pulp mold container is modeled by casting or the like for each shape of the container, and is known to have a plurality of fine holes formed in the surface of a cavity.

Further, the papermaking mold has a vent hole communicating with the surface thereof, a hollow chamber is provided inside the papermaking mold, and a uniform thickness pulp laminate is formed on the papermaking mold surface by uniformly sucking the hollow chamber. And the like are disclosed.

[0005] However, the number of processing steps is increased and the manufacturing cost of the mold is increased. Since the mold is manufactured for each container shape, a large storage space is required for the entire papermaking mold. Further, it is difficult to provide a desired strength in accordance with each part of the pulp laminate, and the thickness of the entire pulp laminate must be more than necessary in accordance with the part requiring the most strength.

SUMMARY OF THE INVENTION An object of the present invention is to provide a papermaking mold of a pulp molded article which can be manufactured by an inexpensive method without requiring complicated processing and can be easily changed in form. It is still another object of the present invention to provide a method for producing a pulp molded article that can be provided with a desired thickness at a necessary portion of a pulp laminate and have a desired strength.

[0007]

According to the first aspect of the present invention,
The above object has been achieved by providing a papermaking mold for a pulp molded article having a plurality of communication holes and a papermaking section and a manifold section which can be exchanged according to the pulp molded article.

According to a second aspect of the present invention, there is provided a papermaking mold according to the first aspect, wherein a rough and dense net layer is applied to the surface of the cavity of the papermaking section. Thereby, the above object has been achieved.

According to a third aspect of the present invention, there is provided the papermaking mold according to the first or second aspect, further comprising a plurality of hollow chambers formed by fitting the manifold section and the papermaking section. The above object has been achieved by providing a method for producing a pulp molded article controlled by each pressure.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific embodiments of the present invention will be described in detail. Embodiment 1 As shown in FIGS. 1 and 2, a papermaking mold for molding a pulp mold hollow container of the present embodiment communicates with a papermaking section 1 having a cavity 3 for forming a pulp mold laminate and the outside. It is constituted by a manifold section 6 provided with a suction port 9 to be used. When the manifold 6 is fitted to the back of the cavity, a hollow chamber 15 is formed which is surrounded by the back of the paper making unit 1, the side wall 7 of the manifold 6, and the nozzle side wall 8. In the block 5 of the paper making section 1 in which the cavity section 3 is formed, a plurality of communication holes 12 communicating from the cavity section 3 to the hollow chamber 15 are formed.

[0011] The ring 11 provided on the manifold 6 is hooked on the hook 10 provided on the paper making unit 1, whereby
The paper making section 1 and the manifold section 6 can be fixed exchangeably. Since the papermaking section 1 varies depending on the type and shape of the pulp molded product, only the papermaking section is replaced and used when the production type is switched. When the paper making section 1 and the manifold section 6 are fitted to each other, by providing the sealing member 19 on the top surface of the side wall 7 of the manifold section 6, it is possible to prevent a reduction in suction efficiency in the hollow chamber.

The method of manufacturing a pulp molded article according to the present embodiment comprises the steps of:
After covering the rough and dense net layers 13 on the respective surfaces of No. 3, the papermaking sections are butted to form a pulp molded product forming section, and a suction port communicating each hollow chamber 15, 15 to the outside. The pulp slurry is injected into the cavities 3 and 3 while the net layers 13 and 13 are brought into close contact with the cavities 3 and 3 by suction from the 9 and 9 to form a pulp laminate 14. Next, the pair of abutted papermaking units 1 and 1 are opened to take out the pulp mold laminate.

The coarse and dense net layers will be described in detail. The net layer is constituted by a first net layer and a second net layer finer than the first net layer, and the first net layer is formed by a cavity portion. 3 and cover the second net layer on the first net layer. Alternatively, a first net layer and a second net layer finer than the first net layer are formed, and the first net layer is placed in close contact with the cavity portion 3 and the second net layer is covered with the first net layer. It is formed on the layer. As described above, the number of the communication holes 12 formed in the block 5 can be reduced by covering or forming the fine second net layer on the coarse first net layer.

For the first net layer and the second net layer, one or more materials made of natural materials, synthetic resins, or metals are used in combination. Further, it is also possible to perform a surface modification coating for improving the slip property, heat resistance and durability of the net layer. Natural materials include plant fibers and animal fibers, and synthetic resins include thermoplastic resins, thermosetting resins, recycled resins, and semi-synthetic resins, and metals include stainless steel.

The first net layer has an average maximum aperture width of 1 to 5
It is preferably 0 mm, more preferably 5 to 10 mm. The opening width indicates a distance between lines of the first net layer. When the average maximum opening width is less than 1 mm, the suction efficiency is deteriorated, and pulp fibers are hardly deposited on the surface of the net layer. As a result, a pulp laminate is hardly formed.
When it is more than m, the second net layer may pass through the space between the first net layers and adhere to the surface of the papermaking mold, and the suction efficiency is locally deteriorated, and the thickness of the pulp laminate becomes uneven.

Further, the first net layer preferably has an average open area ratio of 30 to 95%, more preferably 75 to 90%. If the average open area ratio is less than 30%, the suction efficiency is deteriorated, and a pulp laminate is difficult to be formed. If the average open area ratio is more than 95%, the second net layer may adhere to the surface of the cavity portion 3 in some cases. In addition, the suction efficiency is locally deteriorated, and the thickness of the pulp laminate becomes uneven.

On the other hand, the second net layer preferably has an average maximum opening width of 0.05 to 1.0 mm, more preferably 0.2 to 1.0 mm.
More preferably, it is 0.5 mm. The opening width refers to the inner diameter of each wire of the second net layer. If the average maximum opening width is less than 0.05 mm, the suction efficiency becomes poor,
A pulp laminate is not easily formed, and if it is more than 1.0 mm, pulp fibers are likely to pass through, making it difficult to form a pulp laminate.

The second net layer preferably has an average open area ratio of 30 to 90%, more preferably 50 to 80%. When the average open area ratio is less than 30%, the suction efficiency is deteriorated, so that the pulp laminate is difficult to be formed. It can be difficult.

In this embodiment, the first net layer has an average maximum opening width of 3 to 6 mm, an average opening area ratio of 80 to 92%, and a line width of the first net layer in a state where the first net layer is mounted on the cavity portion 3. A 0.3 mm net was used. The first net layer has an average maximum aperture width of 0.08 to 0.25 m before being attached to the papermaking molds 2 and 3, respectively.
m, the average open area ratio is 46%, and the line width is 0.12 mm. The second net layer has an average maximum aperture width of 0.22 to 0.35 when mounted on the cavity 3.
mm, average hole area ratio is 58 to 69%, and line width is 0.06.
Stockings that were ~ 0.07 mm were used. The second net layer has an average maximum opening width of 0.38 to 0.42 before being attached to the papermaking molds 2 and 3, respectively.
mm, average hole area ratio is 75 to 75%, and line width is 0.05.
０．０0.06 mm. The second net layer only needs to have such a rigidity that it does not come into contact with the surface of the cavity portion 3 through the opening of the first net layer by sucking the hollow chamber 15.

The pulp slurry is obtained by dispersing pulp fibers in water. The pulp fibers are preferably wood pulp such as softwood or hardwood or non-wood pulp such as bamboo or straw. The length and thickness of the pulp fiber are preferably 0.1 mm or more and 10 mm or less, and 0.01 mm or more and 0.05 mm or less. In the present embodiment, in order to manufacture a cylindrical bottle in which the diameter of the nozzle portion is smaller than the diameter of the body portion, the cavity portion 3 having a cavity shape corresponding to the shape of the bottle is used.

Embodiment 2 In the second embodiment, only points different from the above-described first embodiment will be described, and the detailed description of the first embodiment will be applied as appropriate.

In this embodiment, as shown in FIG. 3, a papermaking mold for forming a hollow pulp mold container has partition walls 17 and 17 in a manifold section 20 and a hollow chamber 3
It is divided into two hollow chambers (a first hollow chamber 24, a second hollow chamber 25, and a third hollow chamber 26), and the cavity 3 and each hollow chamber have a plurality of communication holes 12 communicating with each other. A sealing material is provided on an end face (a portion in contact with the paper making section 2) of each of the partition walls 17. Each of the hollow chambers 24, 25, and 26 has a first suction port 21, a second suction port 22, and a third suction port 23 communicating with the outside, respectively, and each suction port can perform independent suction control. It is.

Next, when the pulp molded article of the present embodiment is made of paper, the suction pressure of each of the hollow chambers 24, 25, and 26 is controlled, so that each of the hollow chambers 24, 25, and 26 is provided with a cavity 3 through each communication hole. The suction at the surface can be varied. By this suction control, it is possible to increase the thickness of a desired portion where the strength of the pulp molded article is required. For example, when the suction pressure of only the first hollow chamber is increased, the amount of fibers deposited on the surface of the cavity 3 communicating with the first hollow chamber is made larger than that of the cavity communicating with the other hollow chamber. As a result, it is possible to increase the thickness of the pulp molded article.

Further, by shifting the suction start or suction stop timing for each hollow chamber, it is possible to more accurately control the thickness of the pulp molded product. For example, a pressure gauge (vacuum gauge) is installed at each suction port, and each of the hollow chambers 24, 25, and 26 is independently suctioned at each pressure. When the degree of vacuum drops to a certain set pressure due to the accumulation of pulp fibers in the cavity, the suction of the respective hollow chambers 24, 25, 26 is stopped. As a result, unnecessary suction energy can be saved.

Further, by checking the pressure gauges installed in the respective hollow chambers, it is possible to monitor suction control defects such as breakage of the net layer 13, clogging of the communication holes 12, and suction defects due to a suction device defect.

[0026]

According to the present invention, it is possible to provide a papermaking mold of a pulp molded article which can be manufactured by an inexpensive method without requiring complicated processing and which can be easily changed. Thus, it is possible to provide a method of manufacturing a pulp molded article which can be provided with a desired thickness at a necessary portion of the pulp laminate and have a desired strength.

[Brief description of the drawings]

FIG. 1 shows a mold used in the present embodiment.

FIG. 2 is a diagram in which a rough and dense net layer is covered on a surface of a mold used in the present embodiment to form a pulp mold laminate.

FIG. 3 shows a mold used in the second embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Paper-making part 3 Cavity part 6 Manifold part 9 Suction port 12 Communication hole 13 Net layer 14 Pulp laminated body 15 Hollow chamber 19 Sealing material

Claims (3)

[Claims] 1. A papermaking mold for a pulp molded article having a plurality of communication holes and having a papermaking section and a manifold section which can be exchanged according to the pulp molded article. 2. A papermaking mold for a pulp molded article according to claim 1, wherein a coarse and dense net layer is applied to the surface of the cavity portion of the papermaking portion. 3. The papermaking mold according to claim 1, further comprising a plurality of hollow chambers formed by fitting the manifold section and the papermaking section, and controlling the hollow chambers with respective pressures. Method of manufacturing pulp molded product