JP2002054100A - Method for producing pulp mold formed product - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a pulp mold formed product, capable of preventing occurrence of scratch caused by pulling formed product from a mold. SOLUTION: This method for producing a pulp mold formed product 7 comprises carrying out paper-making forming of the pulp mold formed product 7 on the inner surface of a paper-making mold 1, packing the formed product 7 in a cavity of dried mold 20 in which the cavity having a shape different from a cavity of the paper-making mold 1 is formed and heat-drying the formed product 7. In the method, a prescribed part in the formed product 7 subjected to paper-making forming is deformed toward the interior of the formed product 7 by a prescribed means and a shape of the formed product 7 is formed in a shape capable of packing into the cavity of the dried mold 20 or the formed product 7 is packed into the cavity of the dried mold 20 while deforming the formed product 7.

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 capable of producing a molded article having a complicated shape with a papermaking mold and a papermaking facility having a simple structure. In addition, the present invention prevents the deformation and bottoming out of the bottom after filling the contents,
Also, the present invention relates to a pulp molded article having high mounting stability.

[0002]

2. Description of the Related Art As a method for producing a deep pulp molded body having a rising angle of a side wall of 90 degrees or close thereto, the present applicant has previously disclosed in Japanese Patent Application Laid-Open No. H11-314267. A method for producing a pulp molded article using a papermaking mold and a drying mold composed of a pair of split molds was proposed. According to this method, a molded article having a so-called undercut portion can be easily manufactured.

[0003] However, depending on the shape of the molded article, from the viewpoint of making it easier to remove the molded article from the mold, a papermaking mold must be constructed by combining a large number of split molds, and the structure of the papermaking mold and the papermaking equipment become complicated. Would. In particular, when the papermaking mold is composed of a large number of split dies, there is a high possibility that the pulp slurry leaks from the butted surface of each split mold during papermaking. Further, a method of taking out the molded body from the mold by so-called forcible removal is also conceivable, but in that case, the degree of freedom of the shape of the molded body is limited, and further, there is a possibility that the molded body may be scratched.

Accordingly, an object of the present invention is to provide a method for producing a pulp molded article which can prevent the occurrence of abrasion caused by removing the molded article from a mold. Another object of the present invention is to provide a method for producing a pulp molded article capable of producing a molded article having a complicated shape with a papermaking mold and a papermaking facility having a simple structure.

[0005]

SUMMARY OF THE INVENTION The present invention provides a water-containing pulp mold formed by depositing pulp fibers on an inner surface of a papermaking mold comprising a set of split molds and having a cavity of a predetermined shape formed therein. After the papermaking of the body, the pulp molded article taken out of the papermaking mold is a dry mold in which a cavity formed of a set of split molds and having a shape different from the cavity of the papermaking mold is formed. A method for producing a pulp molded article which is loaded into the cavity and heat-drys the pulp molded article, wherein a predetermined portion of the pulp molded article formed by papermaking is moved into the molded article by predetermined means. After drying, or while deforming the shaped body into a shape that can be loaded into the cavity of the drying mold. It is obtained by achieving the above object by providing a method for producing a pulp molded article which is loaded into the cavity.

Further, the present invention provides a pulp molded article having an opening, a body and a bottom, wherein the bottom has a central recess recessed toward the inside of the molded article and a heel located around the center recess. The present invention also provides a pulp molded article in which the thickness of the central concave portion is larger than the thickness of other portions at the bottom.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described based on preferred embodiments with reference to the drawings. The present embodiment is an example of manufacturing a bottle-shaped pulp molded article (hereinafter, also simply referred to as a molded article) having an open mouth and neck and a trunk having a diameter larger than that of the mouth and neck. FIG. 1 shows a paper making and dewatering step in a first embodiment of a method for producing a pulp molded article of the present invention, wherein (a) is a pulp slurry injection and suction dewatering step, and (b) is a bag. (C) is a pressure dehydration step, and (d) is a step of opening a papermaking mold.

In the present embodiment, a pulp slurry is supplied into the cavity of a papermaking mold comprising a set of mold dies, and a cavity having a predetermined shape is formed by combining the mold dies. After forming a water-containing molded body, the expandable and contractible bag-like body is inserted into the molded body, and then a predetermined fluid is supplied into the bag-like body to expand the bag-like body. The molded body is pressed against the inner surface of the cavity by the bag-like body to dehydrate.

More specifically, as shown in FIG. 1A, first, as shown in FIG. 1A, a papermaking mold 1 comprising two split molds 2 and 3 and forming a cavity 4 having a predetermined shape by combining the split molds. Prepare The cavity 4 communicates with the outside of the papermaking mold 1 through a slurry injection port 5 opened to the outside. The inner surface of the cavity 4 is covered with a papermaking net (not shown) having a mesh of a predetermined size. Each of the split dies 2 and 3 is formed with a plurality of communication passages 6 communicating from the inside (ie, the inner surface of the cavity 4) to the outside. Each communication path 6 is connected to suction means (not shown) such as a suction pump.

In this state, a predetermined amount of pulp slurry is injected into the cavity 4 through the slurry injection port 5.
At the same time, the inside of the cavity 4 is
The pulp fibers are deposited on the papermaking surface, that is, on the papermaking net covering the inner surface of the cavity 4, by suctioning the water under reduced pressure toward the outside of the pulp slurry. As a result, pulp fibers are deposited on the papermaking net, and the water-containing molded body 7 is formed into a paper. This papermaking is performed so that the molded body 7 has an open mouth and neck, a trunk, and a bottom, and the bottom protrudes outward.

The formed compact 7 is subjected to a pressure dehydration step. First, as shown in FIG. 1 (b), an expandable and contractable bag-like body 8 is inserted into a molded body 7 in a contracted state while the papermaking mold 1 is sucked from inside to outside. In the present invention, the expansion and contraction means that the bag-shaped body 8 expands and contracts to change its volume, and the bag-shaped body 8 itself does not expand and contract, but by supplying a fluid to the inside or removing the fluid from the inside, Both cases where the volume changes are included. Examples of the former include bags made of elastic materials such as natural rubber, urethane, fluorine-based rubber, silicone-based rubber or elastomer, and examples of the latter include plastic materials such as polyethylene and polypropylene, and plastics such as these. Examples of the material include a film in which aluminum or silica is deposited on a film of the material, a film in which aluminum foil is laminated on a film of such a plastic material, and a bag made of a flexible material such as paper or cloth. In the present embodiment, a balloon-like one made of an elastic material that can expand and contract is used as the bag-like body 8. If there is no problem in papermaking, the bag-like body 8 may be inserted into the cavity 4 in advance before the supply of the pulp slurry and the molding of the compact 7.

Next, as shown in FIG.
A predetermined fluid is supplied to the inside to expand the bag-like body 8, and the expanded bag-like body 8 presses the hydrated molded body 7 toward the papermaking surface, that is, the inner surface of the cavity 4. As a result, the pressurized dehydration of the molded body 7 proceeds, and the inner surface shape of the cavity 4 is transferred to the molded body 7. As the fluid used for expanding the bag-like body 8, for example, air (pressurized air), a gas such as various inert gases, or a liquid such as oil is used.
In particular, it is preferable to use air in terms of operability and the like. The pressure for supplying the fluid is preferably 0.01 to 5 MPa, particularly preferably 0.1 to 3 MPa.

When the molded body 7 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 7, the fluid in the bag-like body 8 is removed as shown in FIG. Unplug. The bag 8 contracts due to its own contracting force.
Next, the reduced bag-shaped body 8 is taken out of the molded body 7.
Further, the suction in the split mold 3 which is one of the split molds 2 and 3 constituting the paper making mold 1 is stopped, and the paper making mold 1 is opened. When the mold is opened, the problem of removing the molded body 7 does not occur. By this mold opening, the molded body 7 is brought into a state in which the vertical half is held by the other split mold 2 in the suction state. The molded body 7 in this state is in a state where the bottom 9 protrudes outward (downward).

Next, as shown in FIGS. 2A and 2B, the molded body 7 is subjected to a step of inverting and deforming the bottom 9. First, as shown in FIG. 2A, the pressing deformation member 10 is raised from below the bottom 9 toward the bottom 9 while the molded body 7 is held in the split mold 2. The pushing deformation member 10 has an upwardly convex curved surface shape. The pushing deformation member 10 is a rod 11
, And the rod 11 is connected to the cylinder mechanism 12. The pushing deformation member 10 can be moved up and down by the operation of the cylinder mechanism 12.

The push-in deforming member 10 comes into contact with the bottom 9 of the molded body 7 as it rises. The contact position is substantially at the center of the bottom 9. When the push-in deformation member 10 is further raised, FIG.
(B) As shown in FIG.
Is pushed in, and reversely deforms toward the inside of the molded body 7. Thereby, the bottom 9 is formed in a convex shape facing the inside of the molded body 7. In this case, the bottom 9 is deformed so that the top of the bottom of the cavity of the drying mold, which will be described later, is higher than the top of the convex shape, so that the bottom 9 can be easily loaded into the drying mold. That is, a deformation is performed that is more than simply reversing the bottom 9 protruding downward symmetrically.

Next, the molded body 7 is taken out of the split mold 2 by a predetermined means and subjected to a heating and drying step. In the heating and drying step, substantially the same operation as the pressure and dehydration step shown in FIG. 1 is performed, except that the papermaking and dehydration are not performed and a drying mold in a heated state is used. That is, first, a drying mold in which a cavity having a shape corresponding to the outer shape of the pulp molded article to be produced by combining a set of split molds is separately prepared, and the drying mold is heated to a predetermined temperature. .
The cavity corresponding to the bottom of the pulp molded article to be manufactured has a convex shape directed toward the inside of the cavity in the drying mold. Then, into the heated cavity of the drying mold, the compact 7 whose bottom 9 is inverted and deformed to be convex toward the inside is loaded. In this case, as described above, the convex bottom portion 9 is deformed such that the top is higher than the convex top at the bottom of the cavity of the drying mold. 7 is easily loaded into the cavity. Further, since the molded body 7 is still in a water-containing state, it can be slightly deformed, and easily deformed along the shape of the dry mold cavity.

Next, a bag similar to the bag 8 used in the pressure dehydration step shown in FIGS. 1B and 1C is inserted into the molded body, and a fluid is supplied into the bag. The bag is expanded to press the molded body toward the inner surface of the cavity of the drying mold by the expanded bag. The material of the bag and the supply pressure of the fluid can be the same as in the pressurized dehydration step. In this state, the molded body is dried by heating.

When the molded body is sufficiently dried, the fluid in the bag is drained, and the bag is reduced and taken out. Further, the drying mold is opened to take out the target pulp molded article. At the time of removal, the molded body may be slightly forcibly removed, but at this point, the molded body is sufficiently dried and has sufficiently high strength and shape retention properties. Hard to scratch. When the central concave portion 9a (see FIG. 3 described later) at the bottom of the molded body 7 is deep, the drying mold may be replaced with a pair of side part mold and bottom part mold as shown in FIG. It can also be constituted by the following three split molds.

By producing a pulp molded article by the above method, it is possible to effectively prevent the occurrence of scratches due to the removal of the molded article from the mold. Further, it is not necessary to form a papermaking mold used for papermaking of a molded article having a complicated shape from a large number of split molds, and the papermaking mold can be formed from a minimum number of split molds. Reducing the number of split dies is advantageous in that leakage of pulp slurry from the mating surfaces of each split die can be minimized, and that mechanical operations in manufacturing equipment can be simplified. Further, according to the above method, a papermaking mold having a simple structure can be used for papermaking of a molded article having a complicated shape.

As shown in FIG. 3, the molded body 7 obtained in this manner has an open mouth and neck 14, a trunk 15 and a bottom 9 as shown in FIG.
Further, the bottom portion 9 has a central concave portion 9a recessed toward the inside of the molded body 7, and a heel portion 9b located around the central concave portion 9a. The thickness of the central concave portion 9a and the heel portion 9b in the bottom portion 9 is larger than the thickness of other portions in the bottom portion 9. This prevents the bottom 9 from being deformed or falling out after the molded body 7 is filled with the granular material, liquid, or the like. Furthermore, the mounting stability of the compact 9 is also improved. Although it depends on the type of the filler and the size of the molded body, the central recess 9a
And the thickness of the heel portion 9b is 0.1 to 5 mm, particularly 0.1 mm.
It is preferable that the thickness is 3 to 3 mm from the viewpoint of further preventing deformation of the bottom portion 9 and bottoming out. In this case, the thickness of the central concave portion 9a and the thickness of the heel portion 9b may be the same or different. For the same reason, the ratio (former / latter) of the thickness at the minimum thickness portion of the bottom portion 9 to the thickness of the central concave portion 9a is preferably 1 to 50, particularly 3 to 30. When the thickness of the central recess 9a is different from that of the heel 9b, it is preferable that the heel 9b be thicker than the central recess 9a. In this case, it is preferable that the wall thickness gradually decreases or gradually decreases from the heel portion 9b toward the central concave portion 9a. Further, it is preferable that the thickness of the body portion 15 is smaller than the thickness of the central concave portion 9a.

The thickness of the central concave portion 9a refers to the thickness at the position of the central concave portion 9a when the central concave portion 9a has a vertex.
It refers to the average value of any number of positions in the central recess 9a. The thickness of the heel portion 9b refers to the thickness at the position of the vertex when the heel has a vertex in the vertical cross-sectional shape, and is flat when the heel has a flat vertical cross-sectional shape. Means the average value of the position at any number of locations. In addition, it also means the average value of several arbitrary positions on the bottom surface. For example, in the case of a cylindrical molded body, 90
The measurement is performed at four points for each °, and the average value is taken.

Further, the height difference between the central recess 9a and the heel portion 9b is 0.1 to 40 mm, particularly 0.5 to 20 m, in view of preventing deformation of the molded body 7 and prevention of bottoming out, and formability.
m, particularly preferably 1 to 5 mm.

The molded body 7 manufactured by the above-mentioned method has smooth inner and outer surfaces. The degree of smoothness of the molded body 7 is
The center line average roughness (Ra) is 10 μm or less, and the maximum height (R
y) is 50 μm or less (a value measured based on the surface roughness specified in JIS B 0601). Since the inner and outer surfaces are smooth, there is an advantage that when the content such as powder is poured out from the molded body 7, the content hardly remains on the molded body 7. In addition, there is also an advantage that, when a paint is applied to the molded body 7, application is easy. Surfcom 120A (manufactured by Tokyo Seimitsu Co., Ltd.) was used to measure the surface roughness. The measurement conditions were cutoff: 0.80 mm, measurement length: 10.00 mm, filter: 2CR, measurement magnification: 5
00, inclination correction: linear, polarity: standard.

Next, second and third embodiments of the present invention will be described with reference to FIGS. In the second and third embodiments, only the points different from the first embodiment will be described, and the same points will not be particularly described. However, the detailed description of the first embodiment is appropriately applied. . 4 and 5, the same members as those in FIGS. 1 to 3 are denoted by the same reference numerals.

In the second embodiment shown in FIG. 4, the step of reversing the bottom of the molded body 7 is performed without opening the papermaking mold 1. Specifically, after the pressure dehydration step shown in FIG. 1C is completed, the bag 8 is taken out of the molded body 7. Then, while keeping the closed state of the papermaking mold 1, as shown in FIG. 4, a closing hole 13 provided at the bottom of the papermaking mold 1 is opened to communicate the outside of the papermaking mold 1 with the molded body 7. Let it. The closing hole 13 is closed in the paper making / dewatering step of the molded body 7. Next, air is blown from the outside of the papermaking mold 1, that is, the outside of the molded body 7 to the molded body 7 through the closing hole 13. At the same time, air is sucked from the inside of the molded body 7 to the outside of the molded body 7 through the slurry injection port 5. In this case, the communication path 6 of the papermaking mold 1 is set so that no air flows. By blowing and sucking the air, the bottom 9 is formed into a convex shape directed toward the inside of the molded body 7, and the molded body 7 is made to have a shape close to the shape of the cavity of the drying mold and can be loaded into the drying mold.

After the step of reversing the bottom is completed, the papermaking mold 1 is opened, and the hydrated compact 7 is subjected to the same heating and drying process as in the first embodiment.

In the third embodiment shown in FIG. 5, the compact 7 is loaded into a drying mold while performing the step of reversing the bottom of the compact 7. In detail, after opening the papermaking mold 1 shown in FIG. 1D, the molded body 7 is loaded into the drying mold 20 as shown in FIG. Drying mold 20 in the present embodiment
Are composed of three split molds, ie, side split molds 21 and 22 and bottom split mold 23. The cavity forming surface 23a, which is the upper surface of the bottom split mold 23, has a convex shape toward the inside of the cavity corresponding to the bottom of the molded body to be manufactured.

First, the side split molds 21 and 22 are closed, and the mouth, neck and body of the molded body 7 are surrounded by the split molds. Next, when the bottom split mold 23 is raised, the cavity forming surface 23 comes into contact with the bottom 9 of the molded body 7. Bottom split mold 2
When 3 rises, the bottom 9 projecting downward is pushed in, and reversely deforms toward the inside of the molded body 7. Thereby, the bottom 9 is formed in a convex shape toward the inside of the molded body 7 and the closing of the drying mold 20 is completed.

When the closing of the drying mold 20 is completed, the water-containing molded body 7 is subjected to the same heating and drying process as in the first embodiment.

In the second and third embodiments, the same effects as in the first embodiment can be obtained.

The present invention is not limited to the above embodiment. For example, in the above-described embodiment, in the papermaking molding step, the molded body was formed into a paper so that a portion to be deformed in the molded body 7 protrudes outward of the molded body 7.
Depending on the amount of deformation, the molded body does not have to be paper-formed so as to protrude outward.

In the above-described embodiment, the bottom of the molded body is deformed. However, the part to be deformed is not limited to this, and other parts, such as the body, may be deformed according to the shape and use of the molded body. May be.

In the molded article obtained in the above embodiment, the thickness of the central recess at the bottom and the thickness of the heel are:
Although it is larger than the thickness of other parts at the bottom, the thickness of only the central concave part is larger than the thickness of other parts at the bottom, depending on the type of filler and the size of the molded body, etc. If so, the deformation and the detachment of the bottom can be sufficiently prevented.

In the second embodiment, the bottom portion 9 may be reversely deformed by using only one of the air suction and the air blowing according to the shape of the molded body.

[0035]

According to the method for producing a pulp molded article of the present invention, it is possible to effectively prevent the occurrence of abrasion caused by the removal of the molded article from the mold. Further, according to the method for producing a pulp molded article of the present invention, the papermaking mold used for papermaking of a molded article having a complicated shape does not need to be composed of a large number of split dies. A papermaking mold can be configured, the leakage of pulp slurry from the mating surface of each split mold can be minimized, and the mechanical operation in the manufacturing equipment can be simplified. Further, according to the method for producing a pulp molded article of the present invention, a papermaking mold having a simple structure can be used for papermaking of a molded article having a complicated shape.

[Brief description of the drawings]

FIG. 1 is a process diagram sequentially showing a paper making and dewatering step in a first embodiment of a method for producing a pulp molded article according to the present invention. FIG. 1 (a) is a pulp slurry injection and suction dewatering step, and FIG. Fig. 1 (b) shows a step of inserting a bag, Fig. 1 (c) shows a pressure dehydration step, and Fig. 1 (d) shows a step of opening a papermaking mold.

FIG. 2 is a process diagram sequentially showing a step of inverting and deforming the bottom of the molded article in the first embodiment of the method for producing a pulp molded article of the present invention.

FIG. 3 is a longitudinal sectional view of a molded article manufactured according to the first embodiment of the method for producing a pulp molded article of the present invention.

FIG. 4 is a diagram showing a step of inverting and deforming the bottom of a molded article in a second embodiment of the method for producing a pulp molded article of the present invention.

FIG. 5 is a view showing a step of inverting and deforming the bottom of the molded body in the third embodiment of the method for producing a pulp molded body of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Paper making mold 2, 30 split mold 4 Cavity 5 Slurry injection port 6 Communication path 7 Pulp molded article 8 Bag-like body 9 Bottom part 9a Central concave part 9b Heel part 10 Push deformation member 11 Rod 12 Cylinder mechanism 13 Closure hole 14 Neck and neck 15 Body 20 Drying mold 21, 22 Side mold 23 Bottom mold 23a Cavity forming surface

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Minoru Goto, Inventor 2606, Akabane, Kaigamachi, Haga-gun, Tochigi Pref.

Claims (6)

[Claims] 1. A pulp molded article in a water-containing state, in which pulp fibers are deposited, is formed on the inner surface of a papermaking mold comprising a set of split molds and having a cavity of a predetermined shape formed therein. The pulp molded article taken out of the papermaking mold is loaded into the cavity of a drying mold which is formed of a set of split molds and has a cavity having a shape different from the cavity of the papermaking mold, A method for producing a pulp molded article, wherein the pulp molded article is heated and dried, wherein a predetermined portion of the pulp molded article formed by papermaking is deformed toward the inside of the molded article by a predetermined means. After forming the shape of the body into a shape that can be loaded into the cavity of the drying mold, or while deforming, the molded body is loaded into the cavity of the drying mold. Method for producing a pulp molded article to be. 2. The method according to claim 1, wherein the pulp molded article is formed by papermaking so that the predetermined portion protrudes outward, and then the protruding predetermined portion is reversely deformed toward the inside of the molded body. A method for producing a pulp molded article. 3. The pulp molded article is formed into a sheet so as to have an opening, a body, and a bottom, and the bottom is projected outward. The method for producing a pulp molded article according to claim 2, wherein the pulp molded article is reversely deformed. 4. After the deformation by the indentation by the indentation deforming member, or the suction by the air from the molded body to the outside of the molded body and / or the blowing of the air from the outside of the molded body to the molded body. Loading the molded body into the cavity of the drying mold, or deforming the molded body by pushing the molded body into the cavity of the drying mold while pressing the molded body into the cavity of the drying mold. The method for producing a pulp molded article according to any one of claims 1 to 3, which is loaded. 5. A pulp molded product having an opening, a body, and a bottom, wherein the bottom has a central concave portion recessed toward the inside of the molded product and a heel portion located around the central concave portion. A pulp molded article in which the thickness of the recess is larger than the thickness of the other portion at the bottom. 6. The pulp molded article according to claim 5, wherein the thickness of the heel portion is larger than the thickness of another portion of the bottom portion.