JP3125992B2 - Pulp mold container mold - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold for forming a pulp mold container having a mouth and neck, and a method for manufacturing a pulp mold container having a mouth and neck using the mold.

[0002]

2. Description of the Related Art Plastic containers are generally used for packaging containers such as containers and bottles having a lid because they have excellent moldability and are advantageous in terms of productivity. I have. However, since plastic containers have various problems in terms of disposal, a pulp mold container molded by a pulp mold method is considered as an alternative. The pulp mold container can be manufactured at low cost because it can be manufactured using waste paper and recycled paper in addition to being easily disposed of.

As one method of manufacturing a pulp mold container, for example, Japanese Patent Application Laid-Open No.
A method is described in which pulp slurry is injected from a special nozzle into a mesh-shaped mold, high-pressure air is further blown to remove a considerable amount of water, the mold is released, and drying is performed using hot air, infrared rays, or the like.

[0004] However, in the above method, since the pulp fibers do not adhere sufficiently to the surface of the mold, complicated shapes cannot be provided, and variations in product shape and dimensional accuracy are large.
This variation in product shape and dimensional accuracy is particularly noticeable in the mouth and neck of a pulp mold container.

Accordingly, an object of the present invention is to provide a molding die and a neck and neck suitable for manufacturing a pulp mold container having a mouth and neck having a uniform thickness without variation in product shape and dimensional accuracy. It is an object of the present invention to provide a method for producing a pulp mold container having the same.

[0006]

SUMMARY OF THE INVENTION The present invention comprises a pair of split dies having a communication passage for communicating the inside and the outside, and by joining the split dies, the mouth and neck portion to be molded is formed. shape of the cavity corresponding to the outer shape of a container having have been made as a pulp slurry inlet port which is open toward the outside from the neck corresponding cavity in said cavity is formed is formed into the interior, the communicating
The passage has a communication hole formed in the inner surface of the cavity,
A manifold formed inside the split mold and a suction port
Are formed in communication with each other, a molding die of a pulp mold container having a mouth-neck portion, wherein a cross-sectional area of the pulp slurry inflow portion is larger than a cross-sectional area of the mouth-neck portion corresponding cavity portion. The above object has been achieved by providing a mold for a pulp mold container having a reduced size.

Further, the present invention provides a method of manufacturing a pulp mold container having a mouth and a neck using the above-mentioned molding die, wherein the above-mentioned molding die comprising a pair of split dies is abutted on the above-mentioned pulp slurry flow. The pulp slurry is immersed in the pulp slurry with the inlet facing downward, the pulp slurry is sucked through the pulp slurry inlet to deposit pulp fibers on the inner surface of the cavity, thereby forming a pulp molded body, After the mold is pulled up from the pulp slurry, the inside of the cavity is suctioned to dehydrate the pulp molded body, and then the mold is opened to take out the pulp molded body. It is intended to provide a manufacturing method.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First, a preferred embodiment of a mold for forming a pulp mold container (hereinafter, simply referred to as a mold) of the present invention will be described with reference to the production of a bottomed hollow container having a mouth and a neck as an example. It will be described with reference to FIG. Here, FIG. 1 is a view showing one embodiment of the molding die of the present invention.

A molding die 1 shown in FIG.
By abutting the two, a cavity 4 having a shape corresponding to the outer shape of the container having the mouth and neck to be molded is formed inside, and from the mouth and neck corresponding cavity 5 in the cavity 4 to the outside. An open pulp slurry inflow port 6 is formed.

A plurality of communication holes 3 are regularly formed in the inner surface of the cavity 4 over the entire surface. On the other hand, no communication hole is formed in the pulp slurry inlet 6.
The communication holes 3 communicate with respective manifold portions 7 formed inside the split mold 2. The manifold 7 communicates with a suction port 8 provided on the molding die 1 on the side opposite to the side where the pulp slurry inlet 6 is formed. The suction port 8 is connected to a suction device (not shown). As a result, a communication path in which the cavity 4, the communication hole 3, the manifold 7, and the suction port 8 communicate with each other is formed in each of the split dies 2, 2.
Then, as described later, suction is performed from the inside of the cavity 4 to the outside of the molding die 1 through this communication path, and pulp fibers are deposited on the inner surface of the cavity 4 and dewatered of the deposited pulp fibers. Is performed. The formation of the communication hole 3 and the manifold portion 7 in the split mold 2 can be easily performed by means known to those skilled in the art.

Each of the cavity 5 corresponding to the mouth and neck and the pulp slurry inlet 6 in the molding die 1 shown in FIG. 1 has a circular cross-sectional shape, and the diameter of the pulp slurry inlet 6 has a diameter of the mouth and neck. The diameter is smaller than the diameter of the corresponding cavity portion 5. That is, the cross-sectional area of the pulp slurry inlet 6 is smaller than the cross-sectional area of the mouth-and-neck cavity 5. As a result of detailed studies by the present inventors, as shown in FIG. 4, the pulp slurry inlet 6 and the mouth-and-neck cavity 5 have the same cross-sectional shape and the same cross-sectional area. When the container is formed (papermaking) using a mold, the pulp slurry is suctioned to form a pulp fiber layer.
The inflow causes the layer of pulp fiber corresponding to the mouth and neck of the container to be molded to be disturbed, and as a result, the thickness of the mouth and neck in the molded container becomes uneven. It was found to happen. On the other hand, in the present invention, by making the cross-sectional area of the pulp slurry inlet 6 smaller than the cross-sectional area of the mouth-and-neck cavity 5, the pulp fiber layer is effectively prevented from being disturbed. Thus, the thickness of the mouth and neck in the obtained container becomes uniform.

A cross-sectional area of the pulp slurry inlet 6,
The ratio to the cross-sectional area of the mouth-and-neck cavity 5 depends on the size and shape of the container to be molded or the degree to which the pulp slurry is sucked.
0.99, particularly preferably 0.30 to 0.70, is preferable because the thickness of the entire container obtained can be made uniform and the papermaking efficiency can be increased.

In the molding die of the present embodiment, as shown in FIG.
0 is arranged. Thereby, the cross-sectional area of each communication hole 3 formed in each split mold 2 can be increased, and the number thereof can be reduced. This is advantageous in that the split mold 2 can be manufactured at low cost.

In particular, the papermaking net is constituted by a first net layer and a second net layer finer than the first net layer, and the cavity 4 is formed so that the first net layer faces the inner surface side of the cavity 4. It is preferable to adhere along the inner surface. As the first net layer and the second net layer, for example,
A net made of a natural material, a synthetic resin or a metal, or a net made of a combination thereof is used. Plant fibers, animal fibers and the like are used as natural materials, and thermoplastic resins, thermosetting resins, recycled resins, and semi-synthetic resins are used as synthetic resins. Further, in order to improve the slipperiness, heat resistance and durability of these net layers, these net layers may be subjected to a surface modification coating.

The first net layer has an average maximum opening width of 1 to 50 mm, particularly 5 to 5 mm when disposed on the inner surface of the cavity 4.
It is preferably 10 mm. Average maximum opening width is 1m
If it is less than m, the suction efficiency will be poor, and pulp fibers may not be easily deposited on the surface of the papermaking net. 50m
If it is more than m, the second net layer may pass through the line between the first net layers and adhere to the inner surface of the cavity 4, as a result, the suction efficiency may be locally deteriorated, and the thickness of the pulp fiber layer may be reduced. May be uneven. In addition, in this specification, the opening width of the net layer refers to a distance between lines of a linear body constituting the net layer.

The first net layer includes a cavity 4
Has an average open area ratio of 30 to 95 when arranged on the inner surface of
%, Particularly preferably 75 to 90%. When the average open area ratio is less than 30%, the suction efficiency is deteriorated, and a pulp fiber layer is hardly formed. When the average hole area ratio is more than 95%, the second net layer may adhere to the inner surface of the cavity 4 in some cases. As a result, the suction efficiency is locally deteriorated, and the thickness of the pulp fiber layer may be uneven.

On the other hand, the second net layer has an average maximum opening width of 0.05 to 1.0 when arranged on the inner surface of the cavity 4.
mm, particularly preferably 0.2 to 0.5 mm.
When the average maximum opening width is less than 0.05 mm, the suction efficiency is deteriorated, so that the pulp fiber layer may not be easily formed. When the average maximum opening width is more than 1.0 mm, the pulp fiber may easily pass through. In some cases, it may be difficult to form a pulp fiber layer.

The second net layer preferably has an average open area ratio of 30 to 90%, particularly preferably 50 to 80% when arranged on the inner surface of the cavity 4. If the average open area ratio is less than 30%, the suction efficiency becomes poor, so that a pulp fiber layer may not be easily formed. If it is more than 90%, the pulp fiber may easily pass through.
It may be difficult to form a pulp fiber layer.

Next, a preferred method of manufacturing a pulp mold hollow container having a mouth and a neck and having a bottom using the above-described molding die 1 will be described with reference to FIGS. Here, FIG. 2 is a process chart sequentially showing the first half of the process of manufacturing a pulp mold container, (a) is a dipping process of a molding die, (b) is a suction and papermaking process of a pulp slurry, (c)
Is a step of dewatering the pulp compact, and (d) is a step of opening the molding die and removing the pulp compact. FIGS. 3A and 3B are process diagrams sequentially showing the latter half of the process of manufacturing the pulp mold container, wherein FIG. 3A is a process of placing the pulp molded body in a drying mold, and FIG. Insertion step, (c)
Is a pressure / dehydration / drying step of the pulp molded body, (d) is a step of opening the drying mold, and (e) is a step of taking out the pulp mold container.

First, as shown in FIG. 2 (a), a pair of split molds 2, 2 are abutted, and a forming mold 1 in which a papermaking net 20 is arranged along the inner surface of the cavity 4 is pulp-pulled. It is immersed in the pulp slurry 21 with the slurry inlet 6 facing downward. In addition, this papermaking net 20 is
It is composed of the above-mentioned first net layer and a second net layer finer than the first net layer, and the first net layer is in close contact with the inner surface of the cavity 4. In this embodiment, as the first net layer, the average maximum opening width in the state of being disposed on the inner surface of the cavity 4 is 3 to 6 mm, the average opening area ratio is 80 to 92%, and the line width is 0.3 mm. A certain net was used. On the other hand, as the second net layer, the average maximum opening width in a state of being disposed on the inner surface of the cavity 4 is 0.22.
A net having an average opening area ratio of 58 to 69% and a line width of 0.06 to 0.07 mm was used.

Next, as shown in FIG. 2 (b), the inside of the cavity 4 is evacuated using a suction device (not shown) connected to the suction port 8, and the pulp slurry inlet 6 Then, the pulp slurry 21 is sucked and the pulp fibers are deposited on the papermaking net 20 arranged along the inner surface of the cavity 4. Thereby, the pulp molded body 22 is formed on the papermaking net 20. In this case, as described above, since the cross-sectional area of the pulp slurry inlet 6 is smaller than the cross-sectional area of the mouth-neck corresponding cavity 5, the pulp deposited in the mouth-neck corresponding cavity 5 is formed. The fibers are effectively prevented from being disturbed by the inflow of the pulp slurry 21, and the thickness of the mouth and neck in the container to be molded becomes uniform. The degree of suction depends on the size and shape of the container to be molded, but generally ranges from -0.13 to -10.
It is preferably 1.3 kPa, particularly preferably -13.3 to -80.0 kPa.

When a pulp compact 22 having a predetermined thickness is formed, the suction is temporarily stopped, and the mold 1 is pulled up from the pulp slurry 21 as shown in FIG. Then, suction is further performed, and the formed pulp molded body 22 is dehydrated. The degree of dehydration is such that the moisture content of the pulp molded body 22 is 10 to 95% by weight of the pulp molded body 22, especially 40 to 80% by weight.
This is preferred from the viewpoint of shape retention and productivity.

After the pulp compact 22 has been dehydrated to a predetermined moisture content, the mold is opened and the pulp compact 22 is taken out as shown in FIG. 2 (d). In this case, since the pulp molded body 22 has been dehydrated to an extent having sufficient shape-retaining property, there is no possibility that the pulp molded body 22 will lose its shape when taken out.

The pulp molded body 22 taken out is shown in FIG.
As shown in (a), a cavity 32 having a shape corresponding to the outer shape of the container to be molded is formed in the interior thereof by abutting. It is placed in the cavity 32.
The drying mold 30 may be heated or at room temperature, but is preferably heated from the viewpoint of shortening the molding cycle. When the drying mold 30 is heated,
The temperature is preferably from 20 to 300C, particularly preferably from 150 to 250C.

Next, as shown in FIG. 3 (b), a bag-shaped core 33 having elasticity and elasticity is inserted into the pulp molded body 22. The core 33 is inflated like a balloon in the pulp molded body 22, and presses the pulp molded body 22 against the inner surface of the cavity 32 to give the inner surface shape of the cavity 32 and dewater the pulp molded body 22.
Used to dry. Therefore, the core 33 is made of urethane, fluorine, and the like having excellent tensile strength, rebound resilience, and elasticity.
It is preferably formed of a silicone rubber, an elastomer or the like.

Next, as shown in FIG.
A fluid (preferably a heating fluid) is supplied into the
Is expanded, and the pulp molded body 2 is expanded by the expanded core 33.
2 is pressed against the inner surface of the cavity 32. As a result, the pulp molded body 22 is pressed against the inner surface of the cavity 32 by the expanded core 33, and the shape of the inner surface of the cavity 32 is transferred and dehydrated and dried. The pressing time by the core 33 depends on the pressure and temperature of the fluid, the temperature of the drying mold 30, and the like.
Preferably, it is seconds. As the fluid, for example, compressed air, oil, and other various liquids are used. When the supply pressure of the fluid is 9.8 kPa to 4.9 MPa, the pulp compact 22 can be sufficiently pressed against the inner surface of the cavity 32 by the core 33, and the pulp compact 22 is crushed by the core 33. It is preferable because there is no fear. When a heating fluid is used, the temperature is 20 to 300.
It is preferable that it is 150 degreeC, especially 150-250 degreeC.

When the drying of the pulp compact 22 is completed, the fluid in the core 33 is drained as shown in FIG. Then, the core 33 contracts due to the elastic force. Next, the contracted core 33 is taken out from the pulp molded body 22 and the split mold 3 is removed.
The pulp mold container 34 formed as shown in FIG. In addition, depending on the material of the core 33, it may be used as an inner layer of the pulp molded body 22 without taking out the core 33. Thereby, a highly waterproof container can be obtained.

The container 34 thus obtained is shown in FIG.
(E) As shown in (e), a bottomed hollow container having a mouth-neck portion, wherein the thickness of each of the mouth-neck portion 35, the body portion 36, and the bottom portion 37, particularly the thickness of the mouth-neck portion 35, is uniform. Becomes Further, the inner and outer surfaces of the container have good surface properties, and the inner and outer surfaces are beautiful.

Further, according to the method for manufacturing a pulp mold container using the above-described molding die, the container height is high (60 m).
m), a hollow container having a complicated shape, such as one having a cubic curved surface, one having a bottomed or no bottom, as well as one having no draft angle.
For example, a straight shape with no taper angle and a height of 6
Forming a hollow container without a bottom as high as 0 mm or more, a hollow container without a bottom having a tertiary curved surface with a concave body, and a hollow container without a bottom having a tertiary curved surface with a plurality of projections formed on the outer surface of the lower end of the container. Can be. Further, a straight bottomed hollow container having a mouth and neck diameter substantially equal to the bottom diameter and having no taper angle, and a bowl-shaped bottomed hollow container having a mouth and neck diameter larger than the bottom diameter. Can also be formed. Furthermore, a bottomed or non-bottomed container in which the diameter of the mouth and neck is smaller than the diameter of the trunk, a bottomed hollow container having a cylindrical shape with a convex pattern formed on the surface, and a bottomed hollow container in which the trunk is concave , Forming a bottomed hollow container having an outer diameter gradually decreasing toward the bottom side from the mouth and neck side, and a bottomed hollow container having an outer diameter gradually increasing toward the bottom side from the mouth and neck side. Can also.

Although the present invention has been described based on the preferred embodiments, the present invention is not limited to the above embodiments.
For example, depending on the size and number of the communication holes 3 formed in the split mold 2, a papermaking net may not be used. Further, the core 33 may be inserted into the pulp molded body 22 without removing the formed pulp molded body 22 from the papermaking mold 1, and the pulp molded body 22 may be dehydrated and dried. As the split mold 2, a manifold section 7 divided into a plurality of independent sections is used, and the degree of suction of the pulp slurry is adjusted for each manifold section so that the thickness of the pulp molded body 22 is more uniform. It may be made to become.

[0031]

According to the present invention, it is possible to obtain a pulp mold container having a variation in product shape and dimensional accuracy, particularly having a mouth-neck portion having a uniform thickness. In addition, a pulp mold container having good inner and outer surface properties and excellent appearance can be obtained.
Further, a container having a complicated shape such as a tall container, a container having no draft angle, a container having a cubic curved surface, a container with or without a bottom can be formed.

[Brief description of the drawings]

FIG. 1 is a view showing one embodiment of a molding die of the present invention.

FIG. 2 is a process chart sequentially showing a first half of a process of manufacturing a pulp mold container, wherein (a) is a dipping process of a molding die,
(B) is a pulp slurry suction / papermaking step, (c) is a pulp molded article dewatering step, and (d) is a step of opening a molding die and taking out the pulp molded article.

FIG. 3 is a process diagram sequentially showing the latter half of a process of manufacturing a pulp mold container, wherein (a) is a process of putting a pulp compact into a drying mold, and (b) is a core inserting process into a pulp compact. , (C) is a pressurization / dehydration / drying step of the pulp molded body
(D) is a step of opening the drying mold, and (e) is a step of removing the pulp mold container.

FIG. 4 is a schematic diagram showing a comparative molding die.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Molding mold 20 Split mold 3 Communication hole 4 Cavity 5 Cavity part corresponding to mouth and neck part 6 Pulp slurry inflow part 7 Manifold part

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) D21J 3/00-7/00

Claims (6)

(57) [Claims] 1. A shape corresponding to the outer shape of a container having a mouth-and-neck portion to be molded, comprising a pair of split dies having a communication passage communicating between the inside and the outside, and abutting the split dies. And a pulp slurry inflow port opening outward from the mouth-and-neck corresponding cavity portion of the cavity is formed therein, and the communication passage is formed inside the cavity.
Communication hole drilled in the surface, and formed inside the split mold
The manifold section and the suction port section are formed so as to communicate with each other.
Is, a casting mold for pulp molded container having a neck, the cross-sectional area of the pulp slurry inlet port, the molding of the molded pulp container smaller than the cross-sectional area of the port neck corresponding cavity portion Type. 2. A mold for forming a pulp mold container according to claim 1, wherein a papermaking net is arranged along an inner surface of said cavity. 3. A method for producing a pulp mold container having a mouth and a neck using the mold for molding a pulp mold container according to claim 1, wherein the mold for forming a pair of split molds is abutted. ,
A pulp molded body is immersed in pulp slurry with the pulp slurry inlet facing downward, sucking the pulp slurry through the pulp slurry inlet and depositing pulp fibers on the inner surface of the cavity to form a pulp molded body. After forming, the mold is pulled up from the pulp slurry, and the inside of the cavity is suctioned to dehydrate the pulp molded body. After that, the mold is opened to take out the pulp molded body. Manufacturing method of pulp mold container. 4. The inside of the dewatered pulp molded body,
Alternatively, the removed pulp molded body is dried in a mold for drying.
Inside the pulp compact after being placed in the
And insert a core of 9.8 kPa to 4.9 MPa into the core.
The pulp is expanded by supplying a fluid at a supply pressure to expand the core.
The molded body is dried in the cavity of the molding die or the drying.
The mold is pressed into the cavity of the mold and dried.
4. The method for producing a pulp mold container according to 3. 5. The pressing time by said core is 30 to
5. Manufacture of the pulp mold container according to claim 4, which is 300 seconds .
Construction method. 6. The apparatus according to claim 1, wherein said manifold section has a plurality of independent sections.
Pulp slurry for each manifold section.
Claim 1 or Claim 2 in which the degree of suction of Lee is adjustable.
3. A mold for molding the pulp mold container according to 2.