JP2001032199A - Production of pulp-molded body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing pulp-molded body that can readily form a deeply drawn molded body having the side wall rising up almost perpendicularly or having a complicated shape. SOLUTION: The pulp slurry is fed into the cavity 4 of the pulp-screening mold 1 in which the cavity 4 and the pulp slurry inlet 5 allowing the cavity 4 to communicate with the outside are formed by combining the split molds 2, 3 to form a moistening molded body 10 and the wet molded body is drained and dried with heat to give the objective pulp-molded body 10. In this case, a pulp slurry injection pipe 9 is inserted into the pulp slurry inlet 5 and the pulp slurry is injected through the injection pipe 9.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for producing a pulp molded article.

[0002]

2. Description of the Related Art Pulp molded articles are generally produced by the following method. First, a pulp slurry is poured into a female mold having a concave portion of a predetermined shape with a wire mesh, and the female mold is sucked from the outside to deposit pulp fibers on the metal mesh. Then, the deposited pulp fiber is pressed by using a male mold having a shape that can be fitted into the concave portion to give a female concave shape, thereby forming a wet, undried molded body. A pulp molded article is obtained by releasing and drying the undried molded article.

[0003] In this method, however, it is easy to produce a molded product such as a dish or a tray having a shallow bottom, but it is also necessary to produce a molded product having a deep bottom or a complex shape in which a side wall rises almost vertically. It is difficult to do. Also, it is not easy to selectively increase the thickness of a desired portion of the molded body.

Accordingly, an object of the present invention is to provide a method of manufacturing a pulp molded article which can easily produce a molded article having a deep bottom having a substantially vertical side wall and a molded article having a complicated shape. It is another object of the present invention to provide a method for producing a pulp molded article capable of selectively and easily increasing the thickness of a desired portion of the molded article.

[0005]

According to the present invention, there is provided a papermaking mold in which a cavity having a predetermined shape and a pulp slurry inlet for communicating the cavity with the outside are formed by combining a set of split dies. A pulp slurry is supplied into the cavity, and the cavity is sucked from the inside to the outside to form a wet wet compact on the inner surface of the cavity, and then the wet compact is dehydrated and heated and dried. A method of manufacturing a pulp molded article, comprising: inserting a pulp slurry injection pipe into the pulp slurry injection port, and injecting the pulp slurry through the pulp slurry injection pipe to provide a method of manufacturing a pulp molded article. The purpose has been achieved.

Further, the present invention provides a pulp slurry injection pipe preferably used in the above-mentioned production method, wherein a cavity having a predetermined shape is formed by combining a pair of split dies, and a pulp slurry injection port for communicating the cavity with the outside. A pulp slurry injection pipe used to supply pulp slurry into the cavity of the papermaking mold to be formed, wherein the pulp slurry injection pipe has, at a lower end thereof, an outlet closing means for the pulp slurry and the cavity. Pulp slurry injection pipe provided with a partitioning means for partitioning the pulp slurry into two upper and lower chambers in a substantially water-tight manner, and an opening formed on the side surface of the pulp slurry injection pipe to open and close in conjunction with the operation of the partitioning means. Things.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described based on preferred embodiments with reference to the drawings. FIG. 1 is a process diagram schematically showing a paper making / dewatering step in the first embodiment of the method for producing a pulp molded article of the present invention. In FIG. 1, (a) shows a mold assembling step, b) is a papermaking step, (c) is a step of inserting a core, (d) is a pressurization / dehydration step, and (d) is a step of removing a wet undried molded body.

The present embodiment relates to the production of a hollow container (pulp molded article) in the form of a cylindrical bottle having an open mouth and neck. First, as shown in FIG. A papermaking mold 1 in which a cavity 4 having a predetermined shape is formed by bringing the split molds 2 and 3 into contact with each other at their divided surfaces and combining them. In the present embodiment, two split molds 2,
3 make up a set of papermaking molds 1. Cavity 4
Is the part corresponding to the mouth and neck of the molded article to be molded
4a). Split type 2,3
1, a pulp slurry injection port 5 for communicating the cavity 4 with the outside is formed in the upper part of the papermaking mold 1 as shown in FIG. A plurality of communication holes 6 are formed in the inner surface of each of the split dies 2 and 3, and the communication holes 6 are hollow manifolds 7 formed inside the split dies 2 and 3.
Is in communication with The manifold 7 is in communication with a suction port 8 opened to the outside. Thus, a communication path formed by the communication hole 6, the manifold 7, and the suction port 8 is formed in each of the split dies 2 and 3. The communication path communicates the cavity 4 with the outside of the papermaking mold 1. The inner surfaces of the split dies 2 and 3 are covered with nets (not shown) each having a mesh of a predetermined size.

Next, as shown in FIG. 1 (b), a pulp slurry injection pipe 9 is inserted into the pulp slurry injection port 5,
The pulp slurry is supplied into the cavity 4 through the pulp slurry injection pipe 9. In this case, the degree of insertion of the pulp slurry injection pipe 9 is adjusted so that the lower end of the pulp slurry injection pipe 9 is positioned below the mouth-neck portion 4a of the cavity 4. With the supply of the pulp slurry, the split molds 2 and 3 are sucked from the outside through the suction port 8 to decompress the inside of the cavity 4, and the moisture in the pulp slurry is sucked and the pulp fiber is put on the net covering the inner surface of the cavity 4. Deposit. As a result, a molded body 10 formed by depositing pulp fibers is formed on the net. The molded body 10 has an open mouth-neck portion 10 a formed in the mouth-neck portion 4 a in the cavity 4. By supplying the pulp slurry into the cavity 4 through the pulp slurry injection pipe 9 in this manner, the pulp fibers deposited on the net are more effectively exfoliated than when the pulp slurry injection pipe 9 is not used. And the molding 10
Can be formed stably. In particular, the lower end of the pulp slurry injection pipe 9 is connected to the mouth-and-neck portion 4 of the cavity 4.
By locating it below a, it is possible to stably form the mouth and neck portion 10a where the pulp fibers are likely to peel off.

FIG. 2 is an enlarged sectional view showing a main part of a lower end portion of the pulp slurry supply pipe 9. The pulp slurry supply pipe 9 is provided with a pulp slurry outflow closing means and a partition means for dividing the cavity 4 into two upper and lower chambers in a substantially watertight manner. In the present embodiment, the pulp slurry supply pipe 9 has an expandable and contractible annular hollow elastic body 11 surrounding the pulp slurry supply pipe 9.
Function as the outflow closing means together with the partition means.

The hollow elastic body 11 has a part 11b sandwiched between the pulp slurry supply pipe 9 and the ring-shaped fixing member 12, and is fixed to the lower end of the pulp slurry supply pipe 9. The hollow elastic body 11 has a substantially rectangular longitudinal sectional shape, and the lower end 11 a thereof is connected to the pulp slurry supply pipe 9.
Overhangs in the direction of the central axis. Hollow elastic body 11
Is formed of a material having elasticity and capable of expanding and contracting. For example, it is formed of a material such as urethane, fluorine-based rubber, silicone-based rubber, or elastomer having excellent tensile strength, rebound resilience, and stretchability. Further, these materials can be formed by coating a stretchable cloth or the like.

An air supply pipe 13 having a smaller diameter is inserted into the pulp slurry supply pipe 9. The air supply pipe 13 communicates with the hollow elastic body 11 via a communication passage 14 at a lower end thereof. An opening 15 is formed in the side surface of the pulp slurry supply pipe 9 near the position where the hollow elastic body 11 is fixed. The opening 15 opens and closes in accordance with the operation of the hollow elastic body 11 as the partitioning means, that is, expansion and contraction, as described later.

When the hollow elastic body 11 is not operated, it is in a contracted state as shown in FIG. 2 and closes the opening 15. Further, the lower end 9a of the pulp slurry injection pipe 9
Are opened to allow the supply of the pulp slurry into the cavity 4. And the pulp slurry supply pipe 9
The pulp slurry is supplied into the cavity 4 through the pulp slurry supply pipe 9 in this state, while the hollow elastic body 11 is inserted into the cavity in a non-operating state, that is, in a contracted state. This state is a state corresponding to FIG. 1B described above.

A molded body 1 having a predetermined thickness is formed on the inner surface of the cavity 4.
After 0 is formed, the hollow elastic body 11 as the outflow closing means and the partition means is operated. Specifically, as shown in FIG. 3, the hollow elastic body 11 is expanded and deformed through the air supply pipe 13. Thereby, the lower end 1 of the hollow elastic body 11
1 a protrudes further toward the central axis of the pulp slurry supply pipe 9, closes the lower end 9 a of the pulp slurry injection pipe 9, and stops the supply of pulp slurry from the lower end of the pulp slurry injection pipe 9.

Further, due to the expansion deformation of the hollow elastic body 11, the hollow elastic body 11 also projects outwardly and comes into close contact with the molded body 10, thereby partitioning the cavity 4 into two upper and lower chambers almost watertight. Further, in conjunction with the expansion deformation of the hollow elastic body 11, the opening 15 of the pulp slurry injection pipe 9 is released and the opening 15 is opened. As a result, the pulp slurry supplied to the pulp slurry injection pipe 9 is
Is supplied only to the upper chamber 4a of the cavity 4 partitioned into the two chambers. During these series of operations, the interior of the cavity 4 is suctioned under reduced pressure, so that pulp fibers are selectively deposited on the portion of the molded body 10 corresponding to the upper chamber 4a, that is, on the mouth and neck 10a, and the mouth and neck 10a Is formed thick. As a result, the strength of the mouth and neck portion 10a, which is the portion that receives the most load when the molded body is used, is improved.

When the mouth and neck portion 10a is selectively thickened to a predetermined thickness, the supply of the pulp slurry is stopped, and the inside of the hollow elastic body 11 is suctioned under reduced pressure through an air supply pipe to remove the hollow elastic body 11. Reduce the size and release the upper and lower compartments.
Next, the pulp slurry injection pipe 9 is pulled out of the cavity 4.

Referring again to FIG. 1, next, as shown in FIG. 1 (c), the inside of the cavity 4 is sucked under reduced pressure, and the core 16 which is scalable and hollow is inserted into the molded body 10. I do. The core 16 is preferably formed of a material having elasticity and capable of expanding and contracting. The specific material is the same as the material of the hollow elastic body 11 described above.

Next, as shown in FIG.
The pressurized fluid is supplied to the inside to expand the core 16, and the wet molded body 10 wet by the expanded core 16 is pressed against the inner surface of the cavity 4. The molded body 10 has an expanded core 16.
Is pressed against the inner surface of the cavity 4 by the
0, the inner surface shape of the cavity 4 is transferred, and the pressure dehydration proceeds. As described above, since the molded body 10 is pressed from the inside of the cavity 4 to the inner surface of the cavity 4, even if the shape of the inner surface of the cavity 4 is complicated, the shape of the inner surface of the cavity 4 is accurately transferred to the molded body 10. Will be done. Further, it is possible to easily manufacture a deep-bottom molded body whose side wall rises almost vertically. As the pressurized fluid used to expand the core 16, for example, compressed air (heated air), oil (heated oil), and other various liquids are used. The pressure for supplying the pressurized fluid is 0.01 to 5
It is preferable that it is MPa, especially 0.1-3 MPa.

When the shape of the inner surface of the cavity 4 is sufficiently transferred to the molded body 10 and the molded body 10 can be dehydrated to a predetermined moisture content, the pressurized fluid in the core 16 as shown in FIG. And the core 16 is reduced. Next, the reduced core 16 is taken out of the cavity 4, and the papermaking mold 1 is further opened to form the wet molded body 1 having a predetermined moisture content.
Take out 0.

The molded body 10 taken out is then subjected to a heating and drying step. In the heating and drying process, except for using a heating mold in a heated state without performing papermaking and dehydration,
Almost the same operation as the paper making / dewatering step shown in FIG. 1 is performed. That is, first, a heating mold in which a cavity having a shape corresponding to the outer shape of the pulp molded article to be molded is formed by combining a set of split molds is separately prepared, and the heating mold is heated to a predetermined temperature. Heat it. In the present embodiment, the cavity shape of the heating mold and the cavity shape of the papermaking mold are the same. The wet molded body 10 in a wet state is loaded into the cavity of the heated heating mold.

Next, a core similar to the core 16 used in the pressure dehydration step shown in FIG. 1D is inserted into the molded body 10, and a pressurized fluid is supplied into the core to The core is expanded, and the molded body 10 is pressed against the inner surface of the cavity by the expanded core. The material of the core and the supply pressure of the pressurized fluid can be the same as in the pressurized dehydration step. In this state, the compact 1
0 is dried by heating. When the molded body is sufficiently dried, the pressurized fluid in the core is drained, and the core is reduced and taken out. Further, the heating mold is opened, and the pulp molded product is taken out.

Next, a second embodiment of the present invention will be described with reference to FIG. In the second embodiment, only the points different from the first embodiment will be described, and as for the points which are not particularly described, the detailed description regarding the first embodiment will be appropriately applied. In FIG. 4, the same members as those in FIGS. 1 to 3 are denoted by the same reference numerals.

The second embodiment is different from the first embodiment in the structure of the lower end of the pulp slurry supply pipe 9. Pulp slurry supply pipe 9 used in this embodiment
4A, a mushroom valve mechanism 17 as a pulp slurry outflow closing means, a hollow elastic body 11 as a partitioning means, and an opening 15 which opens and closes in conjunction with expansion and contraction of the hollow elastic body 11, as shown in FIG. Have.

The state shown in FIG. 4A is the mushroom valve mechanism 1.
7 and 7 show a non-operating state of the hollow elastic body 11,
This is a state corresponding to FIG. 2 in the first embodiment. In this state, the mushroom valve mechanism 17 is open, and the pulp slurry flows out from the lower end of the pulp slurry supply pipe 9 into the cavity. In this state, the hollow elastic body 11 is in a contracted state and closes the opening 15. The hollow elastic body 11 is different from the hollow elastic body used in the first embodiment, and the lower edge thereof is located at substantially the same position as the lower end 9a of the pulp slurry supply pipe 9 or above the lower end 9a. Does not project toward the center axis of the pulp slurry supply pipe 9.

FIG. 4B shows the operating state of the mushroom valve mechanism 17 and the hollow elastic body 11, and this state corresponds to FIG. 3 in the first embodiment. In this state, the mushroom valve mechanism 17 closes the lower end 9a of the pulp slurry supply pipe 9, whereby the supply of the pulp slurry from the lower end of the pulp slurry injection pipe 9 is stopped. Further, due to the expansion deformation of the hollow elastic body 11, the hollow elastic body 11 projects outward and partitions the cavity into two upper and lower chambers almost watertight. However, unlike the first embodiment, the hollow elastic body 11 does not protrude toward the center axis of the pulp slurry supply pipe 9 even when expanded and deformed. In conjunction with the expansion and deformation of the hollow elastic body 11, the opening 15 of the pulp slurry injection pipe 9 is released and the opening 15 is opened, and the pulp slurry supplied to the pulp slurry injection pipe 9 is opened. Through the section 15, the water is supplied only to the upper chamber of the two-partitioned cavity.

The present invention is not limited to the above embodiment. For example, when a thick part is not formed on the molded body, a pipe having both ends simply opened can be used as the pulp slurry injection pipe 9.

The position at which the cavity is divided into the upper and lower chambers by the partitioning means can be appropriately selected according to which part of the molded body is to be made thicker.

In the above-described embodiment, different molds are used for the paper making / dewatering step and the heating / drying step. However, the paper making / dewatering step and the heating / drying step may be performed by one mold if necessary.

[0029]

According to the method for producing a pulp molded article of the present invention, a molded article having a deep bottom having a side wall rising almost vertically or a molded article having a complicated shape can be easily produced. According to the method for producing a pulp molded article of the present invention, the pulp slurry injection pipe includes the outflow closing means, the partition means, and the opening, so that a desired portion of the molded article can be selectively and easily filled. Can be thick.

[Brief description of the drawings]

FIG. 1 is a process diagram schematically showing a paper making / dewatering step in a first embodiment of a method for producing a pulp molded article of the present invention.

FIG. 2 is an enlarged sectional view showing a main part of a lower end portion of a pulp slurry supply pipe used in the first embodiment of the present invention.

FIG. 3 is a schematic diagram showing a state in which the mouth and neck portion of the pulp molded body is selectively formed to be thick.

FIG. 4 is an enlarged cross-sectional view (corresponding to FIGS. 2 and 3) of a main part of a lower end portion of a pulp slurry injection pipe used in a second embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF REFERENCE NUMERALS 1 papermaking mold 2, 30 split mold 4 cavity 5 pulp slurry injection port 9 pulp slurry injection pipe 10 molded product

Claims (5)

[Claims] A pulp slurry is supplied into a cavity of a papermaking mold in which a cavity having a predetermined shape and a pulp slurry injection port for communicating the cavity with the outside are formed by combining a pair of molds. A method of manufacturing a pulp molded article by suctioning the cavity from the inside to the outside to form a wet undried molded article on the inner surface of the cavity, and then dehydrating and heating and drying the undried molded article. Then, a pulp slurry injection pipe is inserted into the pulp slurry injection port, and the pulp slurry is injected through the pulp slurry injection pipe. 2. The pulp slurry injection pipe, means for closing outflow of pulp slurry, partitioning means for partitioning the cavity into two upper and lower chambers in a substantially watertight manner, and opening and closing in conjunction with the operation of the partitioning means. An opening formed in a side surface of a pipe, and after the molded body having a predetermined thickness is formed on the inner surface of the cavity, the outflow closing means is operated to operate the pulp slurry from a lower end of the pulp slurry injection pipe. And simultaneously operating the partitioning means to partition the cavity into two upper and lower chambers almost watertight, and opening the opening in conjunction with the operation of the partitioning means, through the opening The pulp slurry is supplied only to the upper chamber of the cavities divided into the two chambers, and a portion of the molded body corresponding to the upper chamber is selectively formed into a thick wall. Method for producing a pulp molded article according to claim 1, wherein. 3. The partitioning means is made of a scalable hollow elastic body surrounding the pulp slurry injection pipe, and the opening is formed near the hollow elastic body, and when the hollow elastic body is not operated. When the hollow elastic body is in operation, the hollow elastic body expands and deforms to divide the cavity into two upper and lower chambers, and the hollow elastic body is substantially watertightly closed. The method for producing a pulp molded article according to claim 2, wherein the opening of the opening is opened by closing the blockage. 4. The hollow elastic body also functions as the outflow closing means together with the partitioning means. When the hollow elastic body is not operating, the hollow elastic body is in a contracted state, and a lower end of the pulp slurry injection pipe is provided. 4. The hollow elastic body expands and deforms during operation of the hollow elastic body to close the lower end of the pulp slurry injection pipe.
A method for producing the pulp molded article according to the above. 5. A pulp slurry is supplied into a cavity of a papermaking mold in which a cavity having a predetermined shape is formed by combining a pair of split dies, and a pulp slurry inlet for communicating the cavity with the outside is formed. A pulp slurry injection pipe used for: a pulp slurry injection pipe, at a lower end thereof, an outflow closing means for the pulp slurry, a partition means for partitioning the cavity into upper and lower two chambers in a substantially watertight manner, and A pulp slurry injection pipe that opens and closes in conjunction with the operation and has an opening formed on a side surface of the pulp slurry injection pipe.