JP2000303400A - Production of pulp mold - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a pulp mold, capable of readily producing a hollow molding product having an opening part with a small cross- sectional area. SOLUTION: A pressing member 8 equipped with a central element 81 and a core 82, in a state in which the central element 81 is twisted on the core 82 is inserted into a cavity 4 of a mold 1 provided with a pulp layer 7. A pressurized fluid is fed into the central element 81 and the pulp layer 7 is pressed to the inside of the cavity 4 by the central element 81 to produce a pulp mold molding product.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a pulp molded article, and more particularly to a method for producing a pulp molded article particularly suitable for producing a hollow molded article having a small cross-sectional area of an opening. It relates to a pressing member to be used.

[0002]

2. Description of the Related Art In the production of a pulp molded article, a pair of split molds comprising a male mold and a female mold is used, and a pulp slurry is introduced between the two molds. A method of manufacturing a shallow tray or dish by dewatering the slurry, or forming a splitter using a pair of split dies, and bonding two splitters together to form a hollow molded body such as a bottle. A method for producing is known.

However, in the method using a male type and a female type,
It is not easy to manufacture a molded article having a complicated shape having a so-called undercut portion, and in the laminating method, a seam due to laminating occurs on the surface, and the strength and appearance are impaired. It is not easy to manufacture a hollow molded article having a small cross-sectional area. For example,
When a pulp is pressed to produce a pulp compact having a small opening, it is conceivable to insert a core smaller than the opening, flow a fluid, expand the pressing, and press the pulp. But,
When a small core is used, there is a problem in durability of the core due to excessive expansion. In particular, in the drying step, the core becomes hot, so that the durability is remarkably reduced. In addition, when a small core is expanded, there is also a problem that the pulp is broken or wrinkled due to shear on the pulp surface in the process of expanding the core.

Accordingly, the present invention provides a pulp molded article which can easily produce a complicated shaped article, particularly a hollow molded article having a small cross-sectional area of an opening, without causing a seam to be formed on the surface by bonding. It is an object of the present invention to provide a method for producing the same. Another object of the present invention is to provide a pressing member suitably used in the method for producing a pulp molded article of the present invention.

[0005]

SUMMARY OF THE INVENTION The present invention relates to a method of manufacturing a pulp molded article having a pulp layer formed on an inner surface of a cavity of a mold and drying the pulp layer to obtain a pulp molded article having an opening. The pulp layer is made smaller in advance so as to have a cross-sectional shape smaller than the cross-sectional shape of a portion corresponding to the opening in the pulp layer. After the formation of the core, the reduced core is inserted into the cavity, a pressurized fluid is supplied into the inserted core, and the pulp layer is pressed against the inner surface of the cavity by the core. The above object has been achieved by providing a method for producing a pulp molded article. Further, the present invention is used in the method for producing a pulp molded article according to any one of claims 2 to 6, wherein the pressing member presses the pulp layer against the inner surface of the cavity, and is scalable. And a core which is hollow and comes into contact with the pulp layer by the pressurized fluid supplied therein, and a core inserted into the core, wherein the core is in an inserted state of the core. The above object has been achieved by providing a pressing member which is disposed around the core in a freely twistable manner.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a method for producing a pulp molded article of the present invention will be described based on preferred embodiments with reference to the drawings. The pulp mold manufacturing method of the present embodiment is an example of manufacturing a hollow molded body having an opening, and FIG. 1 shows a paper making step of such a manufacturing step. In FIG. 1, (a) is a papermaking process, (b) is a pressing member insertion process, (c) is a pressure / dehydration process, and (d) is a process of opening a papermaking mold and taking out an intermediate of a molded product. is there.

First, as shown in FIG. 1A, a papermaking mold 1 in which a cavity 4 having a predetermined shape is formed by abutting a pair of split molds 2 and 3 is prepared. Split type 2,
In a state where 3 is abutted, as shown in FIG.
At the upper part of the papermaking mold 1, an opening 5 is formed from the outer surface to the cavity 4. Each of the split dies 2 and 3 is provided with a plurality of communication holes 6 for communicating the outside with the cavity 4. 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, pulp slurry is injected into the cavity 4 through the mouth 5. At the same time, the split dies 2 and 3 are sucked from the outside through the communication holes 6 to depressurize the inside of the cavity 4, suck moisture in the pulp slurry and deposit pulp fibers on the net covering the inner surface of the cavity 4. As a result, a pulp layer 7 on which pulp fibers are deposited is formed on the net. In the pulp layer 7, a portion 7a corresponding to the opening in the molded article to be formed (hereinafter, this portion is referred to as an opening corresponding portion) 7a is formed near the mouth 5 of the papermaking mold 1. The cross-sectional shape of the opening corresponding portion 7a is circular.

When a predetermined amount of the pulp slurry is injected into the cavity 4, the injection of the pulp slurry is stopped and the inside of the cavity 4 is completely sucked and dehydrated. Continuing with FIG.
As shown in (b), the inside of the cavity 4 is suctioned and depressurized, and the pressing member 8 is inserted into the cavity 4 through the mouth 5 of the papermaking mold 1.

The pressing member 8 has a core 81 which is scalable and hollow and has a hollow shape and which comes into contact with the inner surface of the pulp layer 7 by a pressurized fluid supplied therein, and a core 82 inserted into the core 81. Is provided. The core 81 is disposed so as to be twisted around the core 82 when the core 82 is inserted.
The core 81 is twisted around the core 82 in advance, and the pressing member 8 is set in a state in which the cross-sectional shape is smaller than the cross-sectional shape of the opening corresponding portion 7a (hereinafter, this state is referred to as a twisted state). Then, the pressing member 8 in the twisted state is inserted into the cavity 4.

FIGS. 2A and 2B are a side view and an enlarged longitudinal sectional view of a main part of the pressing member 8, respectively. Core 81
Is formed with a flange 81 'at its opening. Then, the flange 81 ′ has the upper fixed plate 9 a and the lower fixed plate 9
The core 81 is fixed to these fixing plates by being sandwiched between the fixing plates 81 and b. The core 81 used in the present embodiment 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.

The core 82 is constituted by a cylindrical pipe. As shown in FIGS. 2A and 2B, a large number of openings 83 are formed on the side surface of the core. A number of annular idle rings 84 are fitted around the core 82 made of this pipe. There is a predetermined clearance between the core 82 and the idling ring 84 so that the idling ring 84 can rotate.

As shown in FIG. 2A, a lower end 82 'of the core 82 is open, and the core 8 is attached to the lower end 82'.
The lower end 82 'is fixed to the core 81 by fitting a projection 81 "having a predetermined shape formed on the inner surface of the lower end of the core 1. The cross-sectional shape of the projection 81" is more elliptical than circular. A polygon or a polygon is preferable because the rotational torque can be increased. The upper end of the core 82 is also open. This upper end is connected to one end of a tubular joint 9c fixed to the upper fixing plate 9a via a ball bearing (not shown). Joint part 9c
Is connected to driving means (not shown) such as a motor,
By the driving means, the joint portion 9c is rotatable around its central axis. The joint 9c
Is connected via a ball bearing (not shown) to a connection portion 9d used for supplying a pressurized fluid described later. As a result, the connection portion 9d moves to the joint portion 9c.
A communication passage for supplying a pressurized fluid to the opening 83 through the inside of the core 82 is formed.

In order to twist the core 81 around the core 82, the joint 9c is rotated by the driving means. Since the core 82 is directly connected to the joint 9c, the core 82 rotates with the rotation of the joint 9c. However, the connecting portion 9d does not rotate because it is connected to the joint portion 9c via the ball bearing. On the other hand, in the core 81, the flange 81 'of the opening is sandwiched and fixed by the upper and lower fixing plates 9a and 9b and the lower end inner surface is fixed to the lower end 82' of the core 82. As the core 82 rotates under the state, the core 82 is gradually twisted. An idle ring 84 is provided on the core 82.
Is fitted, the core 81 is twisted along the surface of the idling ring 84. In this case, since the idling ring 84 is rotatable, it does not rotate with the rotation of the core 82 but idles. As a result, the core 81 twists very smoothly starting from the fixing point with the core 82. Although it depends on the shapes of the core 81 and the core 82, the core 82 is about 2 to 2..
The core 81 is twisted around the core 82 by making five rotations.

When the core 81 is twisted around the core 82,
The cross-sectional shape of the pressing member 8 is smaller than the cross-sectional shape of the opening corresponding portion 7a. More preferably, the inside of the core 81 is depressurized and suctioned through a large number of openings 83 provided in the core 82 so that the air can be almost uniformly and quickly degassed, and even if one opening 83 is closed, the other opening is closed. Since the air can be degassed from 83, the twisted state of the pressing member 8 can be further reduced. Accordingly, the pressing member 8 is inserted into the cavity 4 without coming into contact with the opening corresponding portion 7a, thereby preventing the pulp from falling off the opening corresponding portion 7a and enabling high-speed operation. In addition, the shape of the core 81 (shape in an untwisted state) is substantially the same as or larger than the shape of the cavity 4, so that the expansion ratio of the core 8 can be reduced. It is preferable because durability can be improved.

Returning to FIG. 1 again, as shown in FIG. 1C, the joint 9c is inserted with the pressing member 8 inserted into the cavity 4 and the mouth 5 closed with the lower fixing plate 9b. The core 81 is released from the twisted state by the reverse rotation.
Along with this operation, a predetermined pressurized fluid is supplied from the supply source of the pressurized fluid into the core 82 through the connection portion 9d. The supplied pressurized fluid is supplied to the opening 8 formed in the side surface of the core 82.
3 and further into the core 81 through the clearance between the core 82 and the idle ring (not shown) and the gap between the two idle rings. The split dies 2 and 3 are sucked from the outside together with the supply of the pressurized fluid. This makes core 8
The pulp layer 7 is pressed against the inner surface of the cavity 4 by the expanded core 8. Further, by forming a large number of openings 83 on the side surface of the core 82, the core 81 can expand as a whole and simultaneously, and the pulp layer 7 can be uniformly pressed against the inner surface of the cavity 4, which is preferable. Expanded core 8
1 is similar to the shape of the cavity 4. As the pressurized fluid used to expand the core 81, for example, compressed air (heated air), oil (heated oil), and other various liquids are used. Supply pressure of pressurized fluid is 0.01-5M
Pa, particularly preferably 0.1 to 3 MPa.

The pulp layer 7 is pressed by the core 81.
Then, the inner surface shape of the cavity 4 is transferred to the cavity, and the dehydration further proceeds. Thus, since the pulp layer 7 is pressed against the inner surface of the cavity 4 from the inside 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 pulp layer 7.
Further, since the shape of the expanded core 81 is similar to the shape of the cavity 4 as described above, the pulp layer 7 is pressed with almost the same pressure at any part thereof. As a result, the thickness of the pulp layer 7 becomes uniform. In addition, unlike the conventional manufacturing method, there is no need to use a bonding step, so that the obtained molded article does not have a seam or a thick portion due to bonding. As a result, the strength of the obtained pulp molded article is increased and the appearance impression is improved.

After the shape of the inner surface of the cavity 4 is sufficiently transferred to the pulp layer 7 and the pulp layer 7 can be dehydrated to a predetermined moisture content, as shown in FIG. Pull out. Along with this operation, the joint part 9 c is rotated to rotate the core 82, and the core 81 is twisted around the core 82. As a result, the core 81 returns to the twisted state before insertion. Next, the pressing member 8 is taken out of the cavity 4.
Since the pressing member 8 has the same size as that before being inserted into the cavity 4, the pressing member 8 is taken out of the cavity 4 without contacting the opening corresponding portion 7 a, and
The pulp of a is prevented from falling off. Next, together with the removal of the pressing member 8, the papermaking mold 1 is opened, and a wet pulp molded article 7 'having a predetermined moisture content is removed.

The removed intermediate 7 'is then subjected to a heating and drying step. In the heating / drying step, substantially the same operation as in the paper making step shown in FIG. 1 is performed except that the papermaking / dehydration is not performed and a heated heating mold is used.
That is, first, a heating mold in which a cavity having a shape corresponding to the outer shape of a pulp molded article to be molded is formed by abutting a pair of split molds is heated to a predetermined temperature. Then, the intermediate body in a wet state is loaded into the cavity of the heated heating mold, and the pressing member 8 is pressed.
After pressing and heating and drying the intermediate by using the same pressing member under the same twisting condition, the molded pulp molded product is taken out. After the heating and drying, when the core is taken out of the molded body, even if the core and the pulp layer of the molded body come into contact with each other, the pulp layer has such a high strength that the moldability is not affected. When the core is obtained, the core can be taken out only by suction without taking the core into a twisted state before insertion in the molded body.

The pulp molded article 20 obtained in this manner has an opening 21 and a body 2 as shown in FIG.
2 and a bottom 23, and the cross-sectional area of the opening 21 is
A cylindrical bottle-shaped hollow body smaller than the cross-sectional area of No. 2 is used as a hollow container suitable for storing various contents. Further, in this pulp molded body 20,
The angle between the ground surface of the bottom portion 23 and the outer surface of the side wall of the body portion 22 is substantially 90 °. The height is 50 mm or more, preferably 100 mm or more. Although the container is a deep-bottomed container and has a small cross-sectional area of the opening 21, it is manufactured by the above-described method. In addition, there is no seam in the body 22 by bonding.
In addition, the outer surface and the inner surface are smooth. In particular, the center line average roughness (Ra) is 50 μm or less (JIS B 0
601) and the maximum height (R
y) is 500 μm or less (a value measured according to JIS B 0601). Surfcom 120A (manufactured by Tokyo Seimitsu Co., Ltd.) was used to measure the surface roughness, and the measurement conditions were cutoff: 0.8 mm, measurement length: 10 mm, filter: 2CR, measurement magnification: 500, and tilt correction: Straight line,
Polarity: Standard.

The present invention is not limited to the embodiments described above,
For example, the manufacturing method of the present invention is suitable for manufacturing a bottle-shaped molded body in which the cross-sectional area of the opening is smaller than the cross-sectional area of the body, but a molded body having other shapes, such as a wide opening, The present invention may be applied to the production of a box-shaped carton-shaped molded article. Further, when a molded body having a wide opening and having a shape that does not require much expansion and contraction of the core 81 is formed, the core 81 only needs to have flexibility that can be expanded and contracted. Sex) is not required. Examples of such a material include polyethylene and polypropylene. The pressing members (core, core, etc.) used in the papermaking step and the heating and drying step may have different shapes and materials from each other. In addition, after molding of the molded body 20, a plastic layer or a coating layer is provided on the outer surface and / or the inner surface thereof to further enhance the strength of the molded body 20, effectively prevent leakage of contents, and the like. Or you may give decoration. Further, a reinforcing member made of plastic or the like may be disposed in a portion to which a load is applied when the molded body 20 is used, for example, the opening 21 or the bottom 23 to improve the durability of the molded body 20. Further, some of these parts may be formed of plastic or the like. The opening 21 of the molded body 20
May be a polygon. Further, the manufacturing method of the present invention may be applied to a method of manufacturing an object such as an ornament, in addition to a method of manufacturing a hollow body (hollow container) used for storing contents. In the pressing member according to the present invention, the core is fixed by the fixing plate as in the above-described embodiment, and a projection is provided inside the lower end to be inserted into the lower end of the core. By fixing, it is preferable to arrange the core so that the core can be twisted around the core. For example, when the inside of the core is suctioned under reduced pressure, the lower end of the core is drawn by the suction force. May be sucked and fixed to the lower end of the core, and the core may be disposed so as to be freely twisted around the core.

[0022]

According to the method for producing a pulp molded article of the present invention, a molded article having a complicated shape can be produced without causing a seam due to bonding on the surface. In particular, in the production method of the present invention, when manufacturing a hollow molded body having a small cross-sectional area of the opening, the core is inserted without dropping the pulp at the opening, the pulp is pressed, and the durability of the core is reduced. It is particularly effective because it can be enhanced.
Further, according to the pressing member of the present invention, the method for producing a pulp molded article of the present invention can be suitably performed.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a paper making process in a manufacturing process according to an embodiment of the present invention.

FIG. 2A is a side view of a pressing member, and FIG.
FIG. 2B is an enlarged vertical sectional view of a main part in FIG.

[Explanation of symbols]

 DESCRIPTION OF REFERENCE NUMERALS 1 mold 2, 30 split mold 4 cavity 5 mouth 6 communication hole 7 pulp layer 8 pressing member 81 core 82 core 83 opening 84 84 idle ring 9c joint

────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] July 14, 2000 (2007.1.
4)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claims

[Correction method] Change

[Correction contents]

[Claims]

2. After the core was vacuum aspirated in turn and tang twisted into the core, the manufacturing method of the pulp molded article according to claim 1 wherein the insert within the cavity.

Wherein said core is a hollow body having a plurality of openings on the sides, claim 1 or the pressurized fluid in the core is supplied through the open holes from the interior of the core 2
A method for producing the pulp molded article according to the above.

4. The core is formed of a cylindrical pipe, and a number of annular idle rings are rotatably fitted to the pipe, and the lower end of the core is fixed to the core. The method for producing a pulp molded article according to any one of claims 1 to 3 , wherein the core is twisted around the core by rotating the core.

5. The pulp mold molding according to claim 1 , wherein a projection having a predetermined shape is formed on an inner surface of a lower end of the core, and the projection is fitted into a lower end of the core. How to make the body.

6. used in the production method of the pulp molded article according to any one of claims 1 to 5, a pressing member that presses the pulp layer on the inner surface of the cavity, freely scaling And a core having a hollow shape and abutting on the pulp layer by the pressurized fluid supplied therein, and a core inserted into the core, wherein the core is in an inserted state of the core. A pressing member disposed around the core so as to be twisted freely.

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0005

[Correction method] Change

[Correction contents]

[0005]

SUMMARY OF THE INVENTION The present invention relates to a method of manufacturing a pulp molded article having a pulp layer formed on an inner surface of a cavity of a mold and drying the pulp layer to obtain a pulp molded article having an opening. there are, in advance, to name a and hollow freely scaling, insertion of the core inside
The core thus formed is twisted around the core so as to have a smaller cross-sectional shape than a cross-sectional shape of a portion corresponding to the opening in the pulp layer, and forming the pulp layer A pulp mold that inserts the core in a reduced state into the cavity, supplies a pressurized fluid into the inserted core, and presses the pulp layer against the inner surface of the cavity by the core. The above object has been achieved by providing a method for producing a molded article. Also, the present invention provides any one of claims 1 to 5.
Used in the method of manufacturing a pulp molded article according to the item,
A pressing member for pressing the pulp layer against the inner surface of the cavity, the core being scalable and hollow, and contacting the pulp layer with a pressurized fluid supplied inside, and inserted into the core The above object has been attained by providing a pressing member having a core which is provided so that the core can be twisted around the core in an inserted state of the core. .

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Tokuo Tsuura 2606 Akabane, Kaigamachi, Haga-gun, Tochigi Pref.

Claims (7)

[Claims] 1. A method for manufacturing a pulp molded article, comprising: forming a pulp layer on an inner surface of a cavity of a mold; and drying the pulp layer to obtain a pulp molded article having an opening. The hollow core is made smaller so as to have a smaller cross-sectional shape than the cross-sectional shape of a portion corresponding to the opening in the pulp layer, and the core is reduced after the pulp layer is formed. A method for manufacturing a pulp molded article, wherein the core is inserted into the cavity, a pressurized fluid is supplied into the inserted core, and the pulp layer is pressed against the inner surface of the cavity by the core. 2. The method for producing a pulp molded article according to claim 1, wherein the core is twisted around a core inserted into the core to reduce the core. 3. The method for producing a pulp molded article according to claim 2, wherein the core is twisted around the core, the core is suctioned under reduced pressure, and then the core is inserted into the cavity. 4. The pressurized fluid is supplied to the core from the inside of the core through the openings, the core being a hollow body having a large number of openings on the side surface. 3
A method for producing the pulp molded article according to the above. 5. The core is formed of a cylindrical pipe, and a number of annular idle rings are rotatably fitted to the pipe so that the lower end of the core is fixed to the core. The method for producing a pulp molded article according to any one of claims 2 to 4, wherein the core is twisted around the core by rotating the core. 6. The pulp molding according to claim 2, wherein a projection having a predetermined shape is formed on an inner surface of a lower end of the core, and the projection is inserted into a lower end of the core. How to make the body. 7. A pressing member used in the method for producing a pulp molded article according to claim 2, wherein the pressing member presses the pulp layer against an inner surface of the cavity, and is a scalable and scalable member. And a core having a hollow shape and abutting on the pulp layer by the pressurized fluid supplied therein, and a core inserted into the core, wherein the core is in an inserted state of the core. A pressing member disposed around the core so as to be twisted freely.