JP3960723B2 - Method for producing pulp molded article - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing a pulp mold product that can produce a pulp mold product with high production efficiency.
[0002]
[Prior art and problems to be solved by the invention]
In Japanese Patent No. 2614695, in a method of producing a pulp mold molded body by a dipping method, a mold is immersed in pulp slurry to introduce moisture into the mold, and water is further introduced from the inside of the mold. In addition, it is described that the suction holes of the mold are cleaned by injecting compressed air.
[0003]
According to this method, pulp fibers clogged in the suction holes of the mold can be removed. However, since the clogged pulp fiber removal process is required separately from the molding process, the production cycle becomes longer. Efficiency will decrease.
[0004]
Therefore, an object of this invention is to provide the manufacturing method of the pulp mold molded object which can manufacture a pulp mold molded object with high production efficiency, removing the clogging of a pulp fiber.
Moreover, an object of this invention is to provide the manufacturing method of the pulp mold molded object which can manufacture a pulp mold molded object with high production efficiency, without complicating an apparatus structure.
[0005]
[Means for Solving the Problems]
The present invention injects a predetermined amount of water into a cavity of a predetermined shape formed inside a papermaking mold composed of a set of split molds, and then injects a predetermined amount of high-concentration pulp slurry into the cavity. In addition, while the pulp slurry is being injected or after the pulp slurry is injected, the inside of the cavity is agitated by a predetermined means to dilute the concentration of the high-concentration pulp slurry to the concentration at the time of papermaking, and then opens on the inner surface of the cavity. The diluted water in the pulp slurry is sucked and discharged to the outside of the papermaking mold through a large number of communicating holes, and a shaped fiber having a predetermined shape is formed by depositing pulp fibers on the inner surface of the cavity. The object is achieved by providing a method for producing a pulp molded article.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
The present invention will be described below based on preferred embodiments with reference to the drawings. This embodiment is an example of manufacturing a bottle-shaped pulp mold molded body (hereinafter, also simply referred to as a molded body) having an open mouth-neck portion and a trunk portion having a diameter larger than that of the mouth-neck portion. In FIG. 1, the paper making process of the manufacturing method of the pulp mold molding in this embodiment is shown sequentially, (a) is a water injection process, (b) is a high concentration pulp slurry injection process, (c). Is a stirring step of pulp slurry, and (d) is a suction step.
[0007]
First, the papermaking mold used for the manufacturing method of this embodiment will be described. As shown in FIG. 1, the papermaking mold 1 is composed of two split molds 2 and 3 that form a set of two. The papermaking mold 1 is formed by combining the split molds 2 and 3 to form a cavity 4 having a predetermined shape. The inner surface of the cavity 4 is covered with a papermaking net 5 having a mesh of a predetermined size.
[0008]
Each of the split molds 2 and 3 has a hollow structure having a manifold portion 6. The manifold portion 6 communicates with a connecting pipe 7 that opens toward the outside at the lower part of each split mold 2, 3. A hose 8 is connected to the connecting pipe 7. The hose 8 is connected to an air supply source, a water supply source, and a suction means (all not shown) via a flow path switching valve (not shown). The inner surfaces of the split molds 2 and 3 are surfaces that define the cavity 4, and a plurality of open communication holes 9 are formed on the inner surfaces. The communication hole 9 communicates with the manifold portion 6. Accordingly, in each of the split molds 2 and 3, the communication hole 9, the manifold portion 6, and the connecting pipe 7 communicate with each other. A communication path communicating with the outside of the mold 1 is formed.
[0009]
The cavity 4 communicates with the outside of the papermaking mold 1 through a slurry inlet 10 that opens toward the top of the papermaking mold 1. Further, the papermaking mold 1 has a wall portion 11 standing upright so as to surround the slurry inlet 10, and a buffer tank 12 is formed by the wall portion 11.
[0010]
The production method of the present embodiment using the papermaking mold 1 having the above configuration will be described. First, as shown in FIG. 1 (a), after forming / demolding the molded body in the previous papermaking process, the papermaking is performed through the hose 8. A predetermined amount of water is injected into the cavity 4 from the outside of the mold 1. Thereby, the pulp fiber adhering to and clogging the papermaking net 5 and the communication hole 9 in the cavity 4 by the papermaking process before or before is washed back and removed.
[0011]
This water is also used for diluting a high-concentration pulp slurry described later. Accordingly, it is not necessary to discharge this water out of the papermaking mold 1 prior to the injection of the pulp slurry, so that the production cycle is shortened.
[0012]
As water injected into the cavity 4, it is preferable to use water discharged to the outside of the papermaking mold 1 by suction in the previous or previous papermaking process from the viewpoint of reducing manufacturing costs and shortening the manufacturing cycle. .
[0013]
The amount of water injected into the cavity 4 is appropriately selected according to the injection amount and concentration of the high-concentration pulp slurry subsequently injected into the cavity 4. In the present embodiment, an amount of water larger than the volume of the cavity 4 is injected so that the liquid level of the injected water is located in the buffer tank 12.
[0014]
Next, as shown in FIG. 1B, a high-concentration pulp slurry is poured into the cavity 4 filled with water by the slurry injection tube 13 inserted into the cavity 4 through the slurry injection port 10 of the papermaking mold 1. A predetermined amount is injected. By injecting a high-concentration pulp slurry in this way and diluting it into a low-concentration pulp slurry suitable for papermaking, it is possible to inject a pulp slurry compared to injecting a low-concentration pulp slurry from the beginning. The amount can be reduced. As a result, the time for injecting the pulp slurry is shortened, and the production cycle is shortened. This is particularly effective when manufacturing a molded body having a large volume. Moreover, since it is not necessary to attach a large tank for diluting the pulp slurry to the papermaking mold 1, the apparatus configuration is simplified. As a result, the manufacturing cost can be reduced.
[0015]
The concentration of the high-concentration pulp slurry is generally 1 to 20% by weight, particularly 5 to 15% by weight, although it depends on the injection amount and the amount of water previously injected. Is preferable, and the thickness of the molded body 14 in the paper making process is made uniform.
[0016]
After the high concentration pulp slurry is injected, compressed air is introduced into the cavity 4 from the outside of the papermaking mold 1 through the hose 8 as shown in FIG. Then, the inside of the cavity 4 and the buffer tank 12 are agitated by bubbling of the introduced compressed air, and the injected high-concentration pulp slurry is uniformly diluted to the concentration at the time of papermaking. The introduced compressed air rises in the cavity 4, rises in the buffer tank 12 through a gap between the slurry inlet 10 and the slurry inlet pipe 13, and is discharged to the outside.
[0017]
Next, as shown in FIG. 1 (d), pulp that has been diluted to a predetermined concentration by suctioning the inside of the cavity 4 toward the outside of the papermaking mold 1 through a communication hole 9 that opens to the inner surface of the cavity 4. Water in the slurry is sucked and discharged, and pulp fibers are deposited on the papermaking net 5 covering the papermaking surface, that is, the inner surface of the cavity 4. As a result, a water-containing molded body 14 in which pulp fibers are deposited is formed on the papermaking net 5. Part or all of the discharged water is backwashed with pulp fibers adhering to or clogging the papermaking net 5 or the communication hole 9 in the next or subsequent papermaking process and dilution of high-concentration pulp slurry. Used for.
[0018]
The formed body 14 is then subjected to a pressure dehydration step shown in FIGS. First, as shown in FIG. 2 (a), a hollow core 15 that can be expanded and contracted is inserted into the molded body 14 in the contracted state with the papermaking mold 1 sucked from the inside to the outside. To do. In the present invention, expansion / contraction refers to the case where the volume of the core 15 is expanded and contracted and the volume of the core 15 itself is not expanded or contracted, but the volume of the core 15 is reduced by supplying fluid to the inside or removing the fluid from the inside. It includes both cases in which changes. Examples of the former include cores composed of elastic materials such as natural rubber, urethane, fluorine rubber, silicone rubber, or elastomer, and examples of the latter include plastic materials such as polyethylene and polypropylene, and these plastic materials. Films in which aluminum or silica is vapor-deposited on these films, films in which aluminum foil is laminated on films of these plastic materials, and cores made of flexible materials such as papers and cloths. In the present embodiment, a bag-like (balloon-like) member made of an elastic material that can be expanded and contracted is used as the core 15.
[0019]
Next, as shown in FIG. 2B, a predetermined fluid is supplied into the core 15 to expand the core 15, and the expanded core 15 causes the molded body 14 in a water-containing state to be made into a paper surface, that is, a cavity. Press toward the inner surface of 4. Thereby, the pressure dehydration of the molded body 14 proceeds, and the inner surface shape of the cavity 4 is transferred to the molded body 14. Further, since the molded body 14 is pressed from the inside toward the inner surface of the cavity 4, even if the shape of the cavity 4 is complicated, it is accurately transferred to the molded body 14 on the inner surface of the cavity 4. . As the fluid used for expanding the core 15, for example, air (pressurized air), hot air (heated pressurized air), superheated steam, oil (heated oil), and other various liquids are used. In particular, air, hot air, and superheated steam are preferably used from the viewpoint of operability. The pressure for supplying the fluid is preferably 0.01 to 5 MPa, particularly preferably 0.1 to 3 MPa.
[0020]
When the molded body 14 can be dehydrated to a predetermined moisture content and the shape of the inner surface of the cavity 4 is sufficiently transferred to the molded body 14, the fluid in the core 15 is drained as shown in FIG. 15 is reduced. Next, the reduced core 15 is taken out from the molded body 14, and the papermaking mold 1 is further opened to take out the wet molded body 14 having a predetermined moisture content.
[0021]
The taken-out molded product in the water-containing state is then dried by warm air, infrared rays, or other known heat drying means to obtain a desired pulp molded product.
[0022]
As described above, according to the present embodiment, since the water used for cleaning the papermaking mold 1 is used for diluting the high-concentration pulp slurry, (1) it is necessary to discharge the cleaning water prior to the injection of the high-concentration pulp slurry. (2) Since the injection amount of the high-concentration pulp slurry is small, the production cycle is shortened. In addition, (3) the manufacturing cost is reduced by using the water discharged to the outside of the papermaking mold 1 by suction in the papermaking process before or before the washing water. Further, (4) since it is not necessary to attach a large dilution tank to the papermaking mold 1, the apparatus configuration is simplified, which also reduces the manufacturing cost.
[0023]
The present invention is not limited to the embodiment. For example, in the above-described embodiment, after the high concentration pulp slurry is injected, the compressed air is introduced into the cavity 4 and the inside of the cavity 4 is stirred. Instead, the cavity is injected while the high concentration pulp slurry is injected. Compressed air may be introduced into 4.
[0024]
Further, in order to more efficiently perform the stirring in the cavity 4 by the compressed air, the paper making mold 1 having a structure in which the compressed air is selectively introduced into the cavity 4 from the communication hole 9 positioned below the cavity 4. May be used.
[0025]
Moreover, in the said embodiment, although compressed air was used as a stirring means of the cavity 4, it replaces with this and you may use other stirring means, such as a rotary stirring blade.
[0026]
【The invention's effect】
According to the method for producing a pulp mold product of the present invention, a pulp mold product can be produced with high production efficiency while removing clogging of pulp fibers.
Moreover, according to the manufacturing method of the pulp mold molding of this invention, a pulp mold molding can be manufactured with high production efficiency, without complicating an apparatus structure.
In particular, as the water used for cleaning the papermaking mold, the manufacturing cost is further reduced by using the water discharged to the outside of the papermaking mold by suction in the previous or previous papermaking process.
[Brief description of the drawings]
BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a process chart sequentially illustrating a papermaking process of a method for producing a pulp mold product in the present embodiment.
FIG. 2 is a process chart sequentially showing a pressure dehydration process of a method for producing a pulp mold product in the present embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Papermaking type | mold 2, 3 Split type | mold 4 Cavity 9 Communication hole 10 Slurry injection hole 11 Wall part 12 Buffer tank 13 Slurry injection pipe 14 Molded object 15 Core

Claims (5)

A predetermined amount of water is injected into a cavity of a predetermined shape formed inside a papermaking mold constituted by a set of split molds, and then a predetermined amount of high concentration pulp slurry is injected into the cavity and the pulp is injected. While the slurry is being injected or after the pulp slurry is injected, the inside of the cavity is agitated by a predetermined means to dilute the concentration of the high-concentration pulp slurry to the concentration at the time of papermaking, and then a large number of communication openings that open to the inner surface of the cavity A pulp mold molded body that sucks and discharges the diluted water in the pulp slurry to the outside of the papermaking mold through holes and deposits pulp fibers on the inner surface of the cavity to form a molded body of a predetermined shape. Manufacturing method. After molding and demolding of the molded body, by passing water from the outside of the papermaking mold into the cavity through the communication hole and backwashing, the pulp fibers adhered and clogged in the cavity are removed. The method for producing a pulp molded article according to claim 1, wherein the predetermined amount of water is injected into the cavity while being removed. The method for producing a pulp mold product according to claim 1 or 2, wherein the water injected into the cavity is water discharged to the outside of the papermaking mold by the suction performed before or before. The method for producing a pulp mold product according to claim 1, wherein air is introduced into the cavity to stir the inside of the cavity. The cavity communicates with the outside of the papermaking mold through a slurry inlet opening toward the top of the papermaking mold, and the papermaking mold has a wall on the top so as to surround the slurry inlet. The method for producing a pulp molded article according to claim 4, wherein the buffer tank is formed by the wall portion.

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