JP3807912B2 - Method for producing pulp molded article - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing a pulp mold molded body that can stably pressurize and dehydrate a water-containing pulp mold molded body.
[0002]
[Prior art and problems to be solved by the invention]
The applicant previously disclosed in Japanese Patent Application Laid-Open No. 11-31267, by inserting a hollow core made of an elastic body into a pulp mold molded body formed by papermaking, expanding the core, and pressing the molding by the pressing force. A method for producing a pulp molded body that pressurizes and dehydrates the body was proposed. According to this method, there is an advantage that it is possible to manufacture a deep-bottomed molded body whose side walls rise almost vertically or a molded body having a so-called undercut portion without causing a joint.
[0003]
However, when a bottle-shaped molded body having a small opening is manufactured using the above manufacturing method, for example, in the core insertion step prior to pressure dehydration, a part of the core is in a water-containing state. May come into contact with the body. Since the molded body in a water-containing state is fragile and does not have sufficient shape retention, there is a risk that the pulp fibers constituting the molded body may be peeled off due to contact with the core.
[0004]
By the way, in Japanese Patent Publication No. 35-9669, a core that can be expanded and contracted is inserted into a cavity of a papermaking mold in advance with a support member supported, and pulp slurry is supplied into the cavity under this condition. Then, after forming the molded body by making paper, the pulp mold molded body is formed by expanding the core, depressurizing and dehydrating the molded body with the pressing force, and then pulling out the core from the molded body. The manufacturing method is described.
[0005]
In this method, when the core is pulled out from the molded body, the core may come into contact with the molded body. However, the molded body has already been dehydrated and has sufficient shape retention. In addition, the core pulling-out operation is an operation in which the molded body is less likely to be damaged than the core inserting operation. Therefore, unlike this method proposed by the present applicant, this method is less likely to damage the molded body even if the core contacts. However, in this method, since the core is inserted in the cavity in advance, the flow of the pulp slurry supplied into the cavity is disturbed, and the pulp fibers are not uniformly deposited.
[0006]
Therefore, an object of the present invention is to provide a method for producing a pulp mold molded body that can stably perform pressure dehydration without damaging the water-containing pulp mold molded body.
[0007]
[Means for Solving the Problems]
In the present invention, a hollow core that can be expanded and contracted is inserted into a water-containing pulp mold molded body formed in a papermaking mold by a wet papermaking method, and then the core is expanded and the pressing force is used to In the manufacturing method of a pulp mold molded body for pressurizing and dehydrating a molded body, a molded body main body including the molded body having an opening and an extending portion having a projecting portion extending outward from an end surface of the opening. forming a said core and under a state of being contracted by sucking the is supported and the tang by a support rod inserted therein, the insert into the molded body the body through the extension portion and the opening By providing a method for producing a pulp mold molded body by cutting the molded body main body at a connecting portion between the extended portion and the molded body after pressurization and dehydration of the molded body main body. Achieving purpose Those were.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
The present invention will be described below based on preferred embodiments with reference to the drawings. This embodiment is an example of manufacturing a bottle-shaped pulp mold molded body (hereinafter, also simply referred to as a molded body) having an open mouth-neck portion and a trunk portion having a diameter larger than that of the mouth-neck portion. 1 (a) to 1 (d) sequentially show a paper making process and a dewatering process of the method for producing a pulp molded product of the present invention, and FIG. 1 (a) shows a pulp slurry injection and suction dewatering process. 1 (b) is a core insertion process, FIG. 1 (c) is a pressure dehydration process, and FIG. 1 (d) is a process for opening a papermaking mold. Moreover, FIG.1 (e) is the cutting process of the molded object main body after drying.
[0009]
First, as shown in FIG. 1 (a), a papermaking mold 1 is composed of two split molds 2 and 3 that form a pair, and a cavity 4 having a predetermined shape is formed inside by combining the split molds. prepare. The cavity 4 communicates with the outside of the papermaking mold 1 via a slurry inlet 5 that opens toward 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 split mold 2, 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.
[0010]
The cavity 4 includes a molded body corresponding cavity portion 4a which is a portion corresponding to a pulp mold molded body having an opening, and an extended portion corresponding cavity portion 4b which is a portion corresponding to an extended portion extending from an end surface of the opening. It is composed of
[0011]
Under this condition, a predetermined amount of pulp slurry is injected into the cavity 4 through the slurry inlet 5. At the same time, the inside of the cavity 4 is sucked under reduced pressure toward the outside of the papermaking mold 1 through the communication path 6, and moisture in the pulp slurry is sucked and pulp fibers are put on the papermaking net covering the papermaking surface, that is, the inner surface of the cavity 4. Deposit. As a result, a molded body 7 in a water-containing state in which pulp fibers are deposited is formed on the papermaking net. As shown in FIG. 1A, the molded body 7 is composed of a pulp mold molded body 7a having an opening and an extending portion 7b extending from the end face of the opening.
[0012]
In the molding of the molded body 7, the pulp mold molded body 7 a constituting one of the molded bodies is molded so as to have a bottle shape having an opened neck and neck, a trunk, and a bottom. Further, as shown in FIG. 2 which is an enlarged view of the main part of FIG. 1 (a), an extension part 7b constituting the other side of the molded body 7 is extended outward from the opening end face of the mouth and neck part. Molding is performed so as to have a rising portion 7d rising from the periphery of the portion 7c and the protruding portion 7c.
[0013]
The formed molded body 7 is subjected to a pressure dehydration step. First, as shown in FIG. 1 (b), a hollow elongated bag-like core 8 having a rounded lower end is inserted into the molded body 7. The core 8 is used for pressure dehydration of the molded body 7.
[0014]
A support rod 10 for the core 8 is inserted into the core 8. The support rod 10 is composed of a cylindrical pipe. A large number of apertures 10 a are formed on the side surface of the support bar 10. The lower end 10b of the support bar 10 is open, and the core 8 is supported by the support bar 10 by inserting a projection 8b having a predetermined shape formed on the inner surface of the lower end of the core 8 into the lower end 10b. It is fixed. By supporting the core 8 on the support rod 10, even when the core 8 contacts the molded body 7 when the core 8 is inserted into the molded body 7, Deformation can be stopped only at the contacted part. If the core 8 is not supported by the support rod 10, the entire core 8 will be deformed, making it difficult to insert. In particular, by supporting the core 8 on the support rod 10 at the lower end portion thereof, partial elongation during expansion of the core can be suppressed, and the expanded state can be easily controlled. Further, the insertion of the core 8 is facilitated.
[0015]
The core 8 and the support rod 10 are inserted into the molded body 7 while being fixed to the fixing portion 9 as shown in FIG. FIG. 3 shows the detailed structure of the fixing portion 9. As shown in FIG. 3, the fixing portion 9 includes a driving plate 9a, a pressure bush 9b, and a holder 9c. The driving plate 9a has a flat plate shape, and a through hole is formed in the center thereof. The diameter of the through hole is substantially the same as the diameter of the support rod 10. A support bar 10 is inserted and fixed in the through hole. An annular groove is recessed in the side wall of the through hole, and an O-ring 9d is attached in the annular groove. Airtightness between the through hole and the support rod 10 is maintained by the O-ring 9d. The pressure bush 9b has a cylindrical shape, and a flange portion 9e projecting laterally is formed on the upper portion thereof. And the upper part which the hollow bag-shaped core 8 opened is clamped and fixed by the upper surface of the flange part 9e, and the lower surface of the driving board 9a. The holder 9c holds the flange portion 9e of the pressure bush 9b by being fixed to the driving plate 9a by a fixing screw 9f.
[0016]
The core 8 is inserted into the molded body main body 7 through the opening of the extending portion 7b and the molded body 7a while being supported by the support rod 10 inserted therein. Prior to insertion, the core 8 supported by the support bar 10 is extended to a predetermined length by the support bar 10. Further, the core 8 is sucked in a state where the core 8 is stretched to contract the core 8 to reduce its volume. As a result, the core 8 has a flat shape as shown in FIG. Then, the core 8 that has been drawn and flattened is inserted into the molded body 7 while being supported by the support rod 10. As a result, the portion where the core 8 comes into contact with the molded body 7 is reduced as compared with that before the suction, and the core 8 is stably formed without causing deformation or damage to the pulp molded body 7a. 7 can be inserted. Further, by making the core 8 into a flat shape by suction, the tip of the core 8 can be inserted into the molded body 7 by touching the extending portion 7 b when inserted into the molded body 7. It becomes easy to deform. As the insertion of the core 8 further proceeds, the portion of the core 8 other than the tip is also deformed, so that the contact resistance is reduced, and the core 8 can be inserted very smoothly. Less susceptible to damage. Further, by sucking and contracting the core 8 under the stretched state, the lower end portion of the core becomes thinner and insertion becomes easier. Further, the core 8 described later can be expanded uniformly, and the compact body 7 can be uniformly pressure dehydrated. In addition, the expansion behavior of the core 8 can be stabilized by extending the core 8. The reason for this is that the stress-strain curve of the core 8 which is an elastic body is different between the initial elongation and the stable elongation thereafter, and by stretching the core 8 in advance, a stable elongation region is obtained. It is because it can be expanded by.
[0017]
In addition, since the extended portion 7b of the molded body 7 is formed with the protruding portion 7c protruding outward as described above, for example, the insertion position of the core 8 is shifted and the core 8 is molded. Even if it is inserted into the molded body 7 while being in contact with any part of the body body 7, the overhanging portion 7 c that projects outwardly exerts the pulp fiber locking action and contacts the core 8. It is effectively prevented that the pulp fiber at the portion thus pressed is pushed down together with the core 8. As a result, the core 8 can be efficiently inserted into the molded body main body 7 without further deforming or damaging the pulp mold molded body 7a. The locking action by the overhanging portion 7c becomes more effective when the rising portion 7d is formed on the periphery of the overhanging portion 7c.
[0018]
When the core 8 is flattened by suction, the width becomes larger than before suction (for example, when the cross section of the core 8 is circular, the width of the core 8 after suction is π before suction). ), The core 8 tends to come into contact with the molded body 7 and the molded body 7a may be easily damaged. However, as described above, the contact area between the core 8 and the pulp molded body 7a is reduced by being flattened, the core 8 is easily deformed and the contact resistance is reduced, and the extending portion 7b is present. For example, the possibility that the molded body 7a is damaged by the insertion of the core 8 is smaller when the core 8 is sucked than when the core 8 is not sucked.
[0019]
Although not shown in the figure, the support rod 10 only needs to have a predetermined expansion / contraction mechanism in order to extend the core 8 to a predetermined length by the support rod 10. The extent of extension of the core is 1.1 to 3 times, particularly 1.2 to 2 times in the longitudinal direction (insert direction of the core). From the viewpoint of maintaining the property.
[0020]
For suction in the core 8, the upper end of the support rod 10 is connected to a predetermined suction means, and the suction means is operated so that air in the core 8 is opened on the surface of the support rod 10. This is done by exhausting outside through the hole 10a and the support rod 10.
[0021]
When inserting the core, it is preferable that the cavity 4 of the papermaking mold 1 is further sucked outward so that the compact body 7 is in close contact with the papermaking mold. In this case, at least a portion corresponding to the extended portion 7b in the cavity 4 is sucked and the extended portion 7b is brought into close contact with the papermaking mold 1, so that deformation or damage of the molded body 7a due to contact with the core 8 is further reduced. Become.
[0022]
A core 8 that can be enlarged or reduced is used. In the present invention, expansion / contraction refers to a case where the volume of the core 8 changes due to expansion / contraction, and a case where the core 8 itself does not expand / contract, but by supplying fluid to the inside or removing fluid from the inside thereof, It includes both cases in which changes. Examples of the former include cores composed of elastic materials such as natural rubber, urethane, fluorine rubber, silicone rubber, or elastomer, and examples of the latter include plastic materials such as polyethylene and polypropylene, and these plastic materials. Films in which aluminum or silica is vapor-deposited on these films, films in which aluminum foil is laminated on films of these plastic materials, and cores made of flexible materials such as papers and cloths. In the present embodiment, a bag-like (balloon-like) member made of an elastic material that can be expanded and contracted is used as the core 8.
[0023]
Particularly preferable as a constituent material of the core 8 from the viewpoint of suppressing damage to the molded body 7a is a thickness of 0.5 to 2 mm, particularly 0.7 to 1.5 mm, and a hardness (JIS K 6253) of 15 -50 °, in particular 20-30 °.
[0024]
As shown in FIG. 1 (c), the lower end of the core 8 is positioned near the bottom of the molded body 7 when the insertion of the core 8 is completed. In this state, as shown in the figure, a predetermined pressurized fluid is supplied into the support member 10 from a pressurized fluid supply source (not shown). The supplied pressurized fluid is supplied to the inside of the core 8 through an opening 10 a formed in the side surface of the support member 10. Thereby, the core 8 is expanded. At this time, the state of sucking the cavity 4 of the papermaking mold 1 toward the outside is continued.
[0025]
The molded body body 7 in a water-containing state is pressed toward the paper making surface, that is, the inner surface of the cavity 4 by the expanded core 8. Thereby, the pressure dehydration of the molded body 7 proceeds and the shape of the inner surface of the cavity 4 is transferred to the molded body 7. Further, since the molded body 7 is pressed from the inside toward the inner surface of the cavity 4, the shape of the inner surface of the cavity 4 is accurately transferred to the molded body 7 even if the shape of the cavity 4 is complicated. It will be. Furthermore, it is possible to easily manufacture a deep bottom molded body in which the body side wall rises substantially vertically. Examples of the fluid used for expanding the core 8 include air (pressurized air), hot air (heated pressurized air), superheated steam, oil (heated oil), and other various liquids. In particular, air, hot air, and superheated steam are preferably used from the viewpoint of operability. The pressure for supplying the fluid is preferably 0.01 to 5 MPa, particularly preferably 0.1 to 3 MPa.
[0026]
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 core 8 is drained, and the core 8 is reduced to the original size. Let Next, as shown in FIG. 1 (d), the reduced core 8 is taken out together with the support member 10 from the molded body 7, and the papermaking mold 1 is further opened to dehydrate the molded body 7 to a predetermined moisture content. Take out.
[0027]
The removed molded body is then subjected to a heat drying step. In the heat drying process, papermaking and dehydration are not performed, a heated heating mold is used, and another core having higher heat resistance and durability than the core used in the pressure dehydration process is used. Are substantially the same as those in the pressure dehydration step shown in FIGS. The reason why the core having higher heat resistance and durability than the core used in the pressure dehydration process is used is that the core is expanded and contracted under severer conditions in the heat drying process than in the pressure dehydration process. It is.
[0028]
First, a heating mold in which a cavity having a shape corresponding to the outer shape of the molded body to be molded is formed by combining a pair of split molds, and the heating mold is heated to a predetermined temperature. In this embodiment, the cavity shape of the heating mold and the cavity shape of the papermaking mold are the same. The molded body main body in a water-containing state dehydrated to a predetermined water content is loaded into the heated mold cavity.
[0029]
Next, a core different from the core 8 used in the pressure dehydration step shown in FIGS. 1B to 1D is inserted into the molded body, and a fluid is supplied into the core to supply the core. The core is expanded, and the molded body is pressed against the inner surface of the cavity by the expanded core. When the core is inserted, as in the paper making / dehydrating step described above, the pulp fiber molded body is effectively prevented from being deformed or damaged by the locking action of the pulp fiber by the protruding portion 7c. The material of the core and the supply pressure of the fluid can be the same as those in the pressure dehydration step. Under this condition, the molded body is heated and dried.
[0030]
When inserting the core, it is preferable to reduce the inside of the core by suction, as in the above-described pressure dehydration step, but the core may be inserted without suction. This is because the molded body after dehydration has sufficient shape retention, so that even if it comes into contact with the core to some extent, the molded body is hardly damaged. For the same reason, the core need not be stretched.
[0031]
When the molded body is sufficiently dry, the fluid in the core is drained, and the core is reduced and removed. Further, the heating mold is opened and the molded body is taken out.
[0032]
Next, as shown in FIG.1 (e), the molded object main body 7 taken out from the heating type | mold is a predetermined means in the connection part of the extension part 7b in the molded object main body 7, and the pulp mold molded object 7a. And the extended portion 7b and the pulp mold molded body 7a are separated. As a result, a pulp mold molded body 7a which is a target product is obtained. The separated extended portion 7b is reused as a raw material of the molded body.
[0033]
The present invention is not limited to the embodiment. For example, in the above-described embodiment, the protruding portion 7c of the extending portion 7b has a rising portion 7d formed on the periphery thereof. However, if the pulp fiber locking action by the protruding portion 7c is sufficient, the rising portion 7d may not be formed. Further, the overhanging portion 7c may be inclined and extended upward as in the present embodiment, or may be extended in the horizontal direction.
[0034]
Moreover, the overhang | projection part 7c may be formed discontinuously, if the latching effect | action of the pulp fiber fully expresses.
[0035]
Further, in the heat drying step, a core larger than the opening of the molded body may be used in order to improve the repeated use durability of the core. Also in this case, since the molded body main body dehydrated to a predetermined moisture content has high strength, deformation or damage of the pulp mold molded body can be suppressed even if the core touches the flange.
[0036]
In the above embodiment, a pair of papermaking molds 1 is composed of two split molds 2 and 3, but a papermaking mold is composed of three or more split molds according to the shape of the molded body. May be. The same applies to the heating mold.
[0037]
The production method of the present invention is particularly effective for the production of a bottle-shaped molded body, but can be similarly applied to the production of a box-shaped carton-shaped molded body and other shaped molded bodies. Furthermore, in addition to the shape of the container used to store the contents, the present invention can also be applied to the production of shaped articles having various shapes such as objects such as figurines.
[0038]
As another example of the present invention, the core is supported by a support rod inserted therein, and the inside of the core is sucked and contracted and inserted into the cavity of the papermaking mold. In addition, there may be mentioned a method of forming a molded body by supplying pulp slurry into the cavity and performing wet papermaking. According to this method, since it is not necessary to perform an operation of inserting the core 8, the molded body 7 is not deformed or damaged even in a state where the moisture content immediately after papermaking is high and easily damaged. I do not receive it. Furthermore, the mechanical operation of inserting the core 8 after paper making becomes unnecessary (can be performed in parallel with another operation), and there is an advantage that the entire molding cycle can be shortened.
[0039]
Further, since the slurry is supplied in a state in which the inside of the core 8 is sucked and contracted, the fluctuation of the slurry behavior in the papermaking mold can be reduced, and the uneven thickness of the pulp mold molded body 7a can be suppressed. it can. When the slurry is supplied without contraction due to suction in the core 8, the core 8 pulsates due to the flow of the slurry, and the flow of the slurry in the papermaking mold is disturbed and unstable. Therefore, there is a high possibility that the thickness of the pulp molded body 7a is uneven.
[0040]
Furthermore, in addition to the inside of the core 8 being sucked and contracted, the slurry is supplied in a state in which the core 8 is further contracted by twisting the core 8 around the support rod, etc. The state can be made more stable.
[0041]
According to this alternative method, the moisture content of the molded body 7 dehydrated by pressing the core 8 in the papermaking mold is sufficiently reduced. Therefore, the molded body 7 is moved from the papermaking mold to the drying mold, and another core is used in the drying mold, and this is sucked and shrunk in the same manner as in the heating drying process described above, and then inserted into the molded body 7. By doing so, generation | occurrence | production of the inferior goods by a deformation | transformation and damage of the molded object main body 7 can be made smaller.
[0042]
【The invention's effect】
According to the method for producing a pulp molded article of the present invention, pressure dehydration can be stably performed without damaging the water-containing pulp mold molded article.
[Brief description of the drawings]
BRIEF DESCRIPTION OF DRAWINGS FIG. 1 (a) to FIG. 1 (d) are process diagrams sequentially showing papermaking and dehydration steps of a method for producing a pulp mold molded body of the present invention, and FIG. 1 (e) is a molded body after drying. It is a main body cutting process.
FIG. 2 is an enlarged view of a main part of the molded body main body shown in FIG.
FIG. 3 is a diagram illustrating details of a fixing unit.
FIG. 4 is a schematic diagram showing a cross section of the core in a state of being reduced by suction.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Paper-making type | mold 2, 3 Split type | mold 4 Cavity 4a Molded object corresponding | compatible cavity part 4b Extension part corresponding | compatible cavity part 5 Communication path 6 Slurry inflow path 7 Molded body main body 7a Pulp mold molded object 7b Extension part 7c Overhang | projection part 7d Rising part 8 Core 9 Fixed part 10 Support rod 8 Core

Claims (4)

A hollow core that can be expanded and contracted is inserted into a water-containing pulp mold molded body formed in a paper mold by a wet papermaking method, and then the core is expanded and the molded body is applied by the pressing force. In the method for producing a pulp mold molded body to be pressure-dehydrated , a molded body body is formed which includes the molded body having an opening and an extending portion having an overhang portion extending outward from an end surface of the opening, said core to under a state of being contracted by sucking the is supported and the tang by a support rod inserted therein, the insert into the molded body the body through the extension portion and the opening, the molded article A method for producing a pulp mold molded body, wherein the molded body body is cut at a connecting portion between the extended portion and the molded body in the molded body body after pressure dehydration of the body .
Method.   The pulp according to claim 1, wherein the core is inserted in a state in which at least a portion corresponding to the extending portion in the papermaking mold is sucked outward and the extending portion is in close contact with the papermaking mold. A method for producing a molded body. The manufacturing method of the pulp mold molded object of Claim 1 or 2 with which the said extension part has the said overhang | projection part and the standing | starting-up part which rose upwards from the periphery of this overhang | projection part. The method for producing a pulp mold product according to any one of claims 1 to 3 , wherein the core is sucked and contracted in a state where the core is extended to a predetermined length by the support rod.

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