WO2001068984A1

WO2001068984A1 - Drying mold for pulp mold formed body

Info

Publication number: WO2001068984A1
Application number: PCT/JP2001/000789
Authority: WO
Inventors: Akira Nonomura; Keiji Eto; Yasushi Yamada; Toshio Kobayashi; Kenichi Otani
Original assignee: Kao Corporation
Priority date: 2000-03-13
Filing date: 2001-02-05
Publication date: 2001-09-20

Abstract

A mold used for drying a formed body in the status of being wetted formed using a pulp mold method, comprising a metal mold block (2) having a three-dimensional storage part (20) therein matching the outside shape of the formed body, wherein a plurality of fine exhaust holes (21) are drilled in the storage part (20) and a collective exhaust path (22) leading to the exhaust holes (21) is disposed inside the metal mold block (2).

Description

Description Dry mold for pulp molding

The present invention relates to a dry mold for drying a wet molded product formed by a pulp molding method, and a pulp molded product having a reduced contact area and reduced frictional resistance.

Background art

The drying mold used for drying the wet compact formed by the pulp molding method has an air passage for discharging steam out of the mold. Various types are known as a drying type having such an air passage. For example, (1) a device using a porous mold material as described in Japanese Patent Application Laid-Open No. 8-260400, (2) a material having a net formed on the surface of a porous mold material, (3) As in Patent No. 2,579,875, there is one in which a core vent is arranged in a mold exhaust path.

However, in the dry mold of (1), since the inside of the mold material has minute voids, the steam passage resistance is large, and the escape of steam is not large. In addition, pulp fibers tend to adhere to the mold material and cause clogging, requiring a great deal of maintenance. In addition, the high cost of the molds adds to the manufacturing costs. With the dry mold of (2), traces of the net are transferred to the surface of the molded body, which impairs the appearance of the molded body. Also, since the contact between the mold and the net is line contact, the heat transfer efficiency is insufficient and sufficient heat supply cannot be performed. In the dry type (3), it takes time to attach and adjust the core vent member in the exhaust passage, and it is difficult to attach the core vent to a portion having a small curvature or a screw portion. Also, traces of the outer peripheral contour of the core vent member remain on the surface of the molded product, which is not preferable in appearance. Also, as a technology relating to a dry mold for a pulp molded product, a technology disclosed in UK Patent No. 9394420 is known. In this dry mold, a groove is formed on the surface of the mold body, and a perforated cover is provided on the surface of the mold. Then, heat is supplied from the inner surface on the back side of the mold body by a burner to supply heat.

However, due to the low heat capacity of the dry mold, the temperature stability of the mold could not be said to be good. In other words, when wet moist pulp comes into contact with the molded body, the temperature of the molded body rapidly drops, so that high drying efficiency cannot be obtained. As a countermeasure, if the initial heating temperature of the mold body was raised, the molded product was burnt and discolored. In addition, since the heat capacity of the mold is small, if the thickness of the molded body to be dried is partially different, the temperature of the molded body becomes partially non-uniform and the molded body has uneven drying. Had occurred. Furthermore, since the heat capacity is small, the temperature fluctuation of the mold body is easily influenced by the temperature fluctuation of the burner, and a molded body cannot be obtained stably.

Accordingly, a first object of the present invention is to provide a drying mold for a pulp molded article having high drying efficiency, in which both the efficiency of steam escape and the supply of heat to the molded article are good.

On the other hand, the pulp molded body is subjected to post-processing such as printing, labeling, and coating on the surface after molding, or by a conveyor or other transport line for stocking. Conveyed. However, since the pulp molded product has a higher frictional resistance than the plastic molded product, the pulp molded product comes into contact with the molded product or the molded product and the transport guide during transportation, and the surface of the molded product becomes In some cases, the molded product may be damaged or clogged or caught on the transfer line, causing the line to stop.

In addition, food trays made of pulp molded articles are stacked (stacked). When separating one by one from the stored condition, the trays may not be separated one by one due to the close contact of the trays.

Accordingly, it is a second object of the present invention to provide a pulp molded article which is prevented from being clogged or caught on a transfer line, is hardly damaged, and is hardly damaged.

Disclosure of the invention

The present invention relates to a dry mold of a pulp molded article used for drying a wet molded article formed by a pulp molding method, comprising: a mold having an accommodating portion corresponding to an outer shape of the molded article. A block having a large number of fine exhaust holes in the housing portion, and a portion in which a collective exhaust passage leading to the exhaust holes is provided inside the mold block; The first object has been attained by providing a dry mold of a pulp molded article characterized by having a portion where a collective exhaust passage is not provided.

The present invention has a concave portion or a convex portion having a shape that can be fitted to a wet molded product formed by a pulp molding method, and a large number of concave portions or convex portions are provided on the surface of the concave portion or the convex portion. The first object has been attained by providing a dry mold of a pulp molded article in which a vapor escape groove is formed in a recess and a perforated metal plate is arranged in close contact with the surface.

The present invention relates to a pulp molding de formation feature that many projections are formed at a predetermined position, the individual areas of the convex portion in plan view ^{1. 9 X 1 0- 3 ~} 3. 2 mm ² , a pulp molded article having a pitch of 0.1 to 5 mm and a total area of the projections of 0.5 to 40% with respect to an outer surface area of the pulp molded article. Thus, the second object has been achieved.

BRIEF DESCRIPTION OF THE FIGURES FIG. 1 is a schematic view showing one embodiment of a drying mold for a pulp molded article of the present invention, wherein (a) is a plan view and (b) is a front view.

FIGS. 2A and 2B are views showing a main part of the drying mold according to the embodiment, wherein FIG. 2A is an enlarged plan view of the housing section, and FIG. 2B is an enlarged sectional view of the housing section.

FIG. 3 is a cross-sectional view (an end view corresponding to the arrow a—a in FIG. 1) of the block constituting the dry mold block of the embodiment.

FIG. 4 is an end view (an end view corresponding to the arrow b—b in FIG. 1) of the block constituting the dry mold block of the embodiment.

FIG. 5 is a cross-sectional view (a cross-sectional view corresponding to the arrow c-c in FIG. 1) of a block constituting the dry mold block of the same embodiment.

FIG. 6 is an end view (an end view corresponding to the arrow d--d in FIG. 1) of a block constituting the dry mold block of the embodiment.

FIG. 7 is a cross-sectional view (a cross-sectional view taken along the line e—e in FIG. 1) of the block constituting the dry mold block of the embodiment.

FIG. 8 is a process diagram showing a preferred method of drying a wet pulp molded article using the drying mold of the present embodiment, and (a) is a view showing a state in which the molded article is contained; b) is a diagram showing a state in which the core is inserted, (c) is a diagram showing a pressed state by the core, and (d) is a diagram showing a detached state. FIG. 9 is an exploded perspective view of one embodiment of a dry mold for a pulp molded article of the present invention.

FIGS. 10 (a) and (b) are a front view and a cross-sectional view taken along the line b--b of the drying mold shown in FIG. 9 with the porous metal plate and the holding plate removed, respectively. FIG. 10 is a cross-sectional view (corresponding to FIG. 9 (b)) showing another embodiment (with the multi-hole metal plate removed) of the dry mold of the pulp molded article of the present invention.

FIG. 12 is a perspective view showing one embodiment of the pulp molded article of the present invention. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the present invention will be described based on preferred embodiments with reference to the drawings.

FIG. 1 shows a first embodiment of a dry mold (hereinafter, also simply referred to as a dry mold) of a pulp molded article of the present invention. In the figure, reference numeral 1 indicates a dry type.

The drying mold 1 of the present embodiment is used for drying a wet molded article formed by a pulp molding method. The drying mold 1 is used as a pair, and is used to dry a cylindrical bottle-shaped formed body having a mouth and a neck. As shown in FIG. 1, the drying mold 1 includes a mold block 2 having a housing portion 20 corresponding to the outer shape of a molded body. The accommodating part 20 partially has a large number of fine exhaust holes 21, and gathers with the part where the collective exhaust passage 22 leading to the exhaust holes 21 is provided inside the mold block 2. And a portion where the exhaust path 22 is not provided.

The mold block 2 is formed of a rectangular parallelepiped metal block, and an accommodation portion 20 is recessed on the upper surface side. The upper surface of the peripheral portion of the housing portion 20 is flat, and the upper surface is the dividing surface (butting surface) of the drying mold 1.

The diameter D of the exhaust hole 21 (the distance from the surface of the housing in the exhaust section to the collective exhaust passage, see Fig. 2 (b)) facilitates the escape of steam and prevents clogging by pulp fibers. From the viewpoint of durability and workability of 21, the thickness is preferably from 0.1 to 1 mm, and more preferably from 0.2 to 0.8 mm.

Further, the depth d of the exhaust hole 21 (see FIG. 2 (b)) should be 1 to 10 mm in terms of easy escape of steam, prevention of clogging by fiber, and ease of maintenance. More preferably, it is 2 to 8 mm. This Here, the depth of the exhaust hole 21 refers to the distance from the storage section 20 to the collective exhaust path 22.

The ratio d ZD between the hole diameter D and the depth d of the exhaust hole 21 is the workability of the exhaust hole 21, the deformation of the mold block 2 due to the processing of the exhaust hole 21, and the finishing accuracy of the exhaust hole 21. And preferably from 0.5 to 15, more preferably from 3 to 10.

The exhaust hole 21 has an opening area ratio of the exhaust hole 21 in the accommodation portion 20 and an exhaust hole 21 1 in view of a balance between ease of escape of steam and heat conductivity, and securing strength of the accommodation portion 20. The pitch can be determined as appropriate.

The exhaust holes 21 are patterned so that the accommodating portion 20 is divided into an exhaust portion 23 in which the exhaust holes 21 are formed at a high density and a heat transfer portion 24 having few exhaust holes 21. It is drilled in. The boundary between the exhaust portion and the heat transfer portion is, specifically, a contour connecting the outer edges of the outermost exhaust holes of the exhaust holes 21 formed in the accommodation portion 20 in a pattern arrangement. As defined, drying by heat supply to the molded body is mainly performed through the heat transfer portion, but heat transfer is also performed from a portion other than the exhaust hole 21 in the exhaust portion.

The ratio of the area of the exhaust part 23 to the area of the heat transfer part 24 (the area of the exhaust part) / (the area of the heat transfer part) is 1 Z from the viewpoint of the balance between the ease with which steam can escape and the thermal conductivity. It is preferably from 19 to 11.

The width of the exhaust portion 23 (the interval between adjacent heat transfer portions 24) is preferably 1 to 20 mm, more preferably 2 to 15 mm, and more preferably 4 to 10 mm. Is more preferable. If the width of the exhaust portion 23 is too wide, heat transfer in the exhaust portion 23 will be insufficient and uneven drying will occur.If it is too narrow, the exhaust portion 23 and the corresponding collective exhaust path will become large or complicated. Therefore, processing becomes complicated.

For the opposite reason to the width of the exhaust section, the width of the heat transfer section 24 (adjacent exhaust section 2 (Interval between 3) is preferably 5 to 5 Omm, more preferably 8 to 40 mm, and even more preferably 10 to 3 Omm.

The relationship between the width of the exhaust portion 23 and the depth of the exhaust hole 21 is, from the viewpoint of heat transfer in the exhaust portion 23, (width of the exhaust portion 23) / (depth of the exhaust hole 21). It is preferably 5 or less, more preferably 4 or less, and even more preferably 3 or less.

In the present embodiment, a portion corresponding to the central portion of the mouth portion and the body portion of the molded body, a line pattern with a predetermined interval around the portion, and a portion corresponding to the shoulder portion and the lower portion of the body portion. Exhaust holes 21 are formed in the ring pattern. In this embodiment, the exhaust holes 21 forming each pattern are formed adjacent to each other in a staggered lattice pattern as shown in FIG. 2 (a). In this way, by dividing the housing portion 20 into the exhaust portion 23 and the heat transfer portion 23 according to the drilling pattern of the exhaust holes 21, a large number of exhaust holes 2 are formed in one collective exhaust passage 22. 1 can be assembled, so that efficient exhaust can be achieved even if there are few collective exhaust passages that are difficult to process.

The exhaust port is provided with an exhaust hole 21 such that the area ratio in the storage section 20 is 5 to 50% from the viewpoint of the balance between ease of escape of steam and thermal conductivity and securing the strength of the storage section 20. It is preferable to provide them. In particular, in the case where the pattern arrangement of the exhaust holes 21 is a staggered pattern (the exhaust holes 21 are arranged at the apex of a regular triangle), the opening ratio of the exhaust portion is determined from the point of strength. It is necessary to secure the drilling pitch P of 1 at least twice the hole diameter D. Therefore, staggered

Two

4 ^U (V The open area ratio of the exhaust portion in the case of the element shape is a maximum of 22.7% from the equation (1), and the open area ratio of the exhaust hole 21 in the accommodation portion 20 is preferable from the above area ratio. Or 1.1 (22.7 × 5) to 11.3 (22.7 × 50)%. As shown in FIG. 2 (b), it is preferable that the exhaust hole 21 is formed such that the hole diameter D increases toward the opening end on the housing portion 20 side. As a result, the edge 21a of the opening edge becomes gentle, and clogging of the pulp fiber is less likely to occur, and maintenance is easy. The exhaust hole 21 can be formed by electron beam machining, laser single beam machining, or the like. When drilling the exhaust hole 21, it is preferable to drill it from the side in contact with the molded body in the storage part 20 toward the collecting drainage channel 22.

The collective exhaust passage 22 surrounds the housing portion 20 at a predetermined distance from the housing portion 20 and is formed to penetrate the inside of the mold block 2 in the longitudinal direction. Exhaust holes 21 are drilled so as to be concentrated in the collective exhaust passage 22. In the drying mold 1 of the present embodiment, the collective exhaust passage 22 is formed of 22 A to E, 25 B, and 25 D as described later.

The cross-sectional area (cross-sectional area in the length direction) of the collective exhaust path 22 is preferably from 30 to 400 mm ² , more preferably from 50 to 300 mm ² . If the cross-sectional area is small, the exhaust resistance increases and machining becomes difficult. On the other hand, if it is too large, the heat capacity of the block becomes small, and the stability of the block heat supply decreases.

As shown in FIG. 1, a metal heating block 3 having the same shape as the mold block 2 is fixed to the mold block 2 by a predetermined means on the lower surface side of the mold block 2. Is defined. A plurality of through holes 30 are formed in the heat generating block 3 along its longitudinal direction, and a predetermined heating means, for example, a heating element such as an electric heater (not shown) is formed in the through hole 30. ) Can be inserted. If a heating means is provided in the heat generating block 3, other drying molds may be used depending on the shape of the compact. By sharing with a heating block, mold parts can be shared and mold production costs can be reduced. In addition, the mold exchange can be facilitated.

In the drying mold 1 of the present embodiment, the mold block 2 is divided into five blocks in the longitudinal direction into blocks 2A to 2E so that each block can be fixed by a predetermined fixing means. It has become. By forming the mold block with a plurality of blocks in this way, machining and maintenance are facilitated.

The block 2A shown in FIGS. 1 and 3 is a block corresponding to the mouth of the molded body, and five collecting exhaust passages 22A communicating with the exhaust holes 21A surround the housing portion 20A. It is arranged to be. The block 2B shown in FIGS. 1 and 4 is a block corresponding to the shoulder of the molded body, and a ring-shaped pattern exhaust hole 21B is drilled in the housing portion 20B. These exhaust holes 21B communicate with the collective exhaust passage 22B of a large space. The block 2B is provided with a collective exhaust passage 22B and a collective exhaust passage 25B communicating with a collective exhaust passage 22C of the block 2C described later. Block 2C shown in FIGS. 1 and 5 is a block corresponding to the body of the molded body. Exhaust holes 21C are formed in the housing portion 20C in a row pattern at a predetermined interval. These exhaust holes 21 C lead to five collective exhaust passages 22 C for each row. The block 2D shown in FIG. 1 and FIG. 6 has a ring-shaped pattern of exhaust holes 21D formed in the accommodating portion 20D. Leads to 2D. The block 2D is provided with a collective exhaust passage 22D and a collective exhaust passage 25D communicating with the collective exhaust passage 22C of the block 2C. Block 2E shown in FIGS. 1 and 7 is a block corresponding to the bottom of the molded body, and exhaust holes 21E are punched in the accommodating portion 20E in a line pattern corresponding to the bottom. These exhaust holes 21 E communicate with a collective exhaust passage 22 E in a wide space. Block 2E also communicates with the collective exhaust passage 22D of block 2D, An exhaust path 25E is formed so as to face the collective exhaust path 25D.The collective exhaust path 22E and the exhaust path 25E communicate with an exhaust chamber 26E. The exhaust chamber 26E communicates with an exhaust port 27E formed at the lower end of the block 2E.

The dry molds 1 of the present embodiment are used as a pair, and in a state in which a wet molded body is housed in a cavity formed by two housing sections, the divided surfaces of the molds are abutted with each other to form the molded body. Perform drying.

Next, a preferred method for drying a formed body using the drying mold 1 of the present embodiment will be described with reference to FIG. In FIG. 8, the structure and shape of the dry type are simplified for simplicity. First, as shown in FIG. 8 (a), a predetermined papermaking process is performed in a cavity formed by the two storage portions 20 by abutting the divided surfaces of the two drying dies 1, 1. The pulp molded body 4 formed by the method is accommodated. Both drying dies 1 are previously heated to a predetermined temperature by the heating element arranged in the mold block 2.

Next, as shown in FIG. 8 (b), the hollow bag-shaped core 5 is inserted into the molded body 4. It is preferable that the core 5 has elasticity and can expand and contract. The core 5 is preferably formed of urethane, fluorine-based rubber, silicone-based rubber, elastomer, or the like having excellent tensile strength, rebound resilience, elasticity and the like.

Next, as shown in FIG. 8 (c), a pressurized fluid is supplied into the core 5 to expand the core 5, and the molded body 4 in a wet state by the expanded core 5 is placed in the storage section 2. Press on the inner surface of 0. The molded body 4 is pressed against the inner surface of the housing by the expanded core 5, and the drying of the molded body 4 proceeds, and the shape of the inner surface of the housing 20 is transferred to the molded body 4. As described above, the molded body 4 is pressed against the housing from the inside of the molded body 4 to the outside, so that the molded body 4 is dried with high drying efficiency even if the inner surface shape of the housing is complicated, and The accommodation section of 20 The inner surface shape is transferred to the molded body 2 with high accuracy. Further, by setting the diameter of the exhaust hole 21 drilled in the housing portion 20 within the above-described range, the surface of the housing portion 20 of the drying mold 1 is not easily deformed by the pressing by the core 5. It becomes bad. As the pressurized fluid used to expand the core 5, for example, compressed air (heated air), oil (heated oil), and various other liquids are used. Further, the pressure for supplying the pressurized fluid is preferably from 0.01 to 5 MPa, particularly preferably from 0 :! to 3 MPa.

When the molded body 4 has been sufficiently dried to a predetermined moisture content, as shown in FIG. 8 (d), the pressurized fluid in the core 5 is drained, and the core 5 is reduced. Next, the reduced core 5 is taken out of the molded body 4, and the drying molds 1, 1 are opened to take out the molded body 4.

As described above, the drying mold 1 of the present embodiment has good steam escaping efficiency and good heat supply to the molded body, and has high drying efficiency. In particular, since the accommodating portion 20 is divided into the exhaust portion and the heat transfer portion by the exhaust hole 21 formed in a predetermined pattern, efficient drying can be performed even if the number of collective exhaust passages is small. it can. In other words, since the number of collective exhaust passages is small, the heat conduction part is large, sufficient heat can be supplied, and the heat capacity is large, so that the temperature stability of the dry type is high. In addition, since minute exhaust holes 21 are densely formed in the collective exhaust passage, the exhaust efficiency is extremely high. Further, since the mold block 2 can be divided in the longitudinal direction, maintenance work such as cleaning can be easily performed.

FIG. 9 is an exploded perspective view of a second embodiment of the drying mold of the present invention, and FIGS. 10 (a) and (b) show the porous metal plate and the holding plate from the drying mold shown in FIG. The front view and the cross section taken along the line b-b are shown respectively.

As shown in FIG. 9 and FIG. 10, the dry mold 101 has a concave portion 111. Perforated metal plate that fits into the recessed portion of the back plate 120 and the cavity plate 110 located on the lower surface side of the cavity plate 110 and the cavity plate 110 And a holding plate 140 for fixing the porous metal plate 130 to the cavity plate 110.

In the present embodiment, two dry molds 101 shown in FIGS. 9 and 10 are used, and a molded body in a wet state is accommodated in a cavity formed by two concave portions 111. Then, the molded body is dried by abutting the divided surfaces.

The cavity plate 110 is composed of a rectangular parallelepiped metal block, and the upper surface of the cavity plate is fitted with a vertical half of a wet molded body formed by a predetermined method. A recessed portion 1 11 having a shape that can be formed is provided, and the molded body is accommodated in the recessed portion 1 11. The upper surface of the cavity plate 110 is flat, and this surface becomes the dividing surface (butting surface) of the dry mold 101.

On the inner surface of the concave portion 111, a large number of steam escape grooves 112 are formed in a lattice shape. The steam escape groove 112 is formed in the concave portion 111 in a portion corresponding to the body and bottom of the molded body to be dried. The portion surrounded by the vapor escape groove 1 1 2 forms a truncated quadrangular pyramid-shaped convex portion 1 1 3 having a prismatic shape or a nearly right-angled rising angle.

The width of the steam escape groove 1 1 2 is 0.5 to 30 mm, especially from the viewpoint of improving the steam escape efficiency and preventing uneven steam escape, uneven heating of the pulp fiber and deformation of the perforated metal plate. It is preferably about 10 mm. The pitch of the steam escape grooves 112 is determined from the width of the steam escape grooves 112 and a desired contact ratio with the porous metal plate 130. The greater the depth of the steam escape groove 1 12, the higher the steam escape efficiency. However, from the point of view of the machining process, 1 mm or more, especially 3 mm or more, is sufficient. At the vertical and horizontal intersections of the steam escape grooves 1 12, steam escape holes 114 are formed radially and regularly in the normal direction of the concave portion 111. The steam escape holes 114 are preferably formed with a pitch that is at least twice the pitch of the steam escape grooves 112. Note that the steam escape hole 114 is also formed in the concave portion 111 in a portion corresponding to the mouth and neck of the molded article to be dried.

Inside the cavity plate 110, a through hole 115 is formed along the longitudinal direction thereof so as to communicate with the steam escape hole 114. As a result, the inside of the cavity plate 110 is a communication passage that connects the steam escape groove 1 12 to the outside of the drying mold 101 by the steam escape hole 114 and the through hole 115. Is formed. Then, the steam generated by drying the wet compact is discharged to the outside of the drying mold 101 through the communication passage.

The perforated metal plate 130 is formed by pressing a thin plate-shaped metal plate with a large number of holes 131 formed by punching, electron beam processing, laser processing, etc., and has a cavity plate. It has a recessed portion 132 shaped to fit into the recessed portion 111 of 110 and a flange 133 extending horizontally from the periphery of the recessed portion 132. The hole 13 1 is formed at least over the entire area of the recess 1 32. Drilling of the perforated metal plate 130 is facilitated by making it thinner.

The perforated metal plate 130 has a thickness of 0.1 to 10 mm, particularly 0.4 to 5 mm, and especially 0.8 to 3 mm. Securing, easy formation of holes 131, difficulty in clogging of pulp fibers into holes 131, perforated metal plate 130 ease of press working, easy release of steam, etc. Preferred from the point. When the molded body is pressed by a core described later in the drying step, by setting the thickness in the above range, the porous metal plate 130 is easily deformed, and the porous metal plate 130 and the cavity are formed. The surface of the concave portion 111 of the plate 110 adheres well to the layer, and the efficiency of heat conduction is improved. Also, porous metal By smoothing the surfaces of the plate 130 and the concave portion 111, the efficiency of heat conduction is further improved.

The perforated metal plate 130 has a hole area ratio of the hole 131 in the recessed portion 132 of 0.5 to 70%, particularly:! It is preferable that the content be within a range of from 40% to 40% in terms of the balance between the ease with which steam can escape and the thermal conductivity, and the strength of the porous metal plate 130.

The perforated metal plate 130 having a pore diameter of 0.05 to 2 mm, particularly 0.1 to 0.6 mm facilitates the escape of steam and prevents clogging of pulp fibers. Further, it is preferable in that the marks of the holes 13 1 are prevented from being transferred to the surface of the molded article in a convex shape.

The pitch of the holes 13 1 is determined from the hole area ratio and the hole diameter described above. The apparent contact area between the concave portion 111 of the cavity plate 110 and the porous metal plate 130 is 10 to 90% of the apparent area of the concave portion 111, especially 30 to 6%. 0% is preferable from the viewpoint of the balance between ease of vapor escape and thermal conductivity. Here, the “apparent contact area between the concave portion 111 of the cavity plate 110 and the perforated metal plate 130” means that the perforated metal plate 130 has no holes. Means the contact area between the porous metal plate 130 and the surface of the concave portion 111, and in the present embodiment, corresponds to the total area of the upper surface of the convex portion 113 in the concave portion 111. The “apparent area of the concave portion 111” refers to the surface area of the concave portion 111 before the vapor escape groove 112 is formed in the concave portion 111.

When the concave portion 1 32 of the porous metal plate 130 is fitted into the concave portion 1 1 1 of the cavity plate 110, the concave portion 1 32 is in surface contact with the concave portion 1 1 1. It is in close contact. Thereby, the heat transfer efficiency is improved, and the drying efficiency of the molded body is improved.

The perforated metal plate 130 has a concave plate 132 that has a cavity plate 110. It is pressed by a holding plate 140 of the same shape as the flange 133 of the perforated metal plate 130 in a state of being fitted to the concave portion 111 of the perforated metal plate 130. In detail, the flange 13 is clamped by the holding plate 140 and the stepped portion 116 formed on the periphery of the concave portion 111 of the cavity plate 110. The holding plate 140 and the perforated metal plate 130 are detachably fixed to the cavity plate 110 by means of 141. Since the perforated metal plate 130 is detachably fixed in this manner, even if clogging of the pulp fiber occurs in the perforated metal plate 130, it can be easily removed and washed, and the dry mold 1 0 1 is excellent in its maintainability.

On the underside of the cavity plate 110, a back plate 120 made of the same metal block as the cavity plate 110 is fixed to the cavity plate 110 by predetermined means. Have been. A plurality of through holes are formed in the knock plate 120 along its longitudinal direction, and a predetermined heating means, for example, a heating element 121 such as an electric heater is inserted into the through hole. Have been. When a heating means is provided on the back plate 120, by sharing it with another dry mold back plate according to the shape of the compact, the mold parts can be shared and the production cost of the mold can be reduced. I can do it. It is also possible to easily change the mold.

A preferred method for drying a molded body using the drying mold 101 of the present embodiment will be described with reference to FIG.

First, as shown in FIG. 8 (a), the divided surfaces of the two drying dies 101, 101 are abutted against each other to form a cavity formed by the two concave portions 111. Next, a pulp molded article 4 molded by a predetermined papermaking method is accommodated. Both drying dies 101 are previously heated to a predetermined temperature by a heating element arranged on the back plate.

Next, as shown in FIG. 8 (b), a hollow bag-shaped core 5 is placed in the molded body 4. insert. It is preferable that the core 5 has elasticity and can expand and contract. The core 5 is preferably formed of urethane, fluorine-based rubber, silicone-based rubber, elastomer, or the like having excellent tensile strength, rebound resilience, elasticity and the like.

Next, as shown in FIG. 8 (c), a pressurized fluid is supplied into the core 5 to expand the core 5, and the molded body 4 in a wet state is expanded by the expanded core 5. 11 Press against the perforated metal plate (not shown) arranged on the inner surface of 1. The molded body 4 is pressed against the inner surface of the porous metal plate by the expanded core 5, and the shape of the porous metal plate is transferred to the molded body 4 as drying of the molded body 4 proceeds. As described above, since the compact 4 is pressed against the porous metal plate from the inside to the outside of the compact 4, the compact 4 is dried with high drying efficiency even if the shape of the porous metal plate is complicated. In addition, the shape of the perforated metal plate is transferred to the molded body 4 with high accuracy. In addition, since the porous metal plate is deformed by the pressing by the core 5 and comes into close contact with the inner surface of the concave portion 111, the heat transfer efficiency is further improved. As the pressurized fluid used to expand the core 5, for example, compressed air (heated air), oil (heated oil), and other various liquids are used. Further, the pressure for supplying the pressurized fluid is preferably from 0.01 to 5 MPa, particularly preferably from 0.1 to 3 MPa.

When the molded body 4 has been sufficiently dried to a predetermined moisture content, as shown in FIG. 8 (d), the pressurized fluid in the core 5 is drained, and the core 5 is reduced. Next, the reduced core 5 is taken out of the molded body 4, and the drying molds 101 and 101 are further opened to take out the molded body 4.

FIG. 13 is a perspective view of an embodiment of the pulp molded article of the present invention. As shown in FIG. 13, the pulp molded article 201 of the present embodiment is in the form of a hollow cylinder having a cylindrical shape. The molded body 201 has an open mouth and neck part 202, a trunk part 203 and a bottom part 204, These parts are connected smoothly and seamlessly.

The diameter of the mouth and neck portion 202 is smaller than the diameter of the torso portion 203. In addition, a screw thread 205 is formed on the outer peripheral surface of the mouth and neck portion 202, and the screw thread 205 is adapted to be screwed with a cap (not shown).

The molded body 201 is formed using pulp as a main raw material. Of course, it may be formed from 100% of pulp. When another material is used in addition to the pulp, the amount of the material is preferably 1 to 70% by weight, particularly preferably 5 to 50% by weight. Other materials include inorganic substances such as talc and kaolinite, inorganic fibers such as glass fiber and carbon fiber, synthetic resin powder such as polyolefin, synthetic fiber, non-wood or vegetable fiber, and polysaccharides. Can be Thus, in the molded body 201 of the present embodiment, a large number of projections 206 are formed on the body 203. Each of the projections 206 has an independent dot shape when viewed in a plan view. Each convex portion 206 has a hemispherical three-dimensional shape, and is circular in plan view.

Individual areas of the projections 2 0 6 in a plan view, 1. 9 X 1 0- is ³ ~ ^3. ² mm 2, preferably 0. 0 3~ 0. 8 mm ^2, further favored properly 0 . a 0 7 1 X~ 0. 2 8 mm 2. The area 1. 9 X 1 0- ³ when mm Ru ² below der, the height of the convex portion 2 0 6 is too low it is difficult to form the protrusions 2 0 6, also the convex portions 2 0 There is no significant difference from the case without 6. If it is more than 3.2 mm ² , the shape of the convex portion 206 is too large, so that it is difficult to mold with high accuracy, and the appearance of the molded body 201 is impaired.

The convex portion 206 is formed regularly in the body portion 203 of the molded body 1. The pitch of the projections 206 in the height direction of the molded body 201 is 0.1 to 5 mm, and preferably 0.4 to 3 mm. If the pitch is less than 0.1 mm, the protrusions 206 are formed too densely, and the frictional resistance is no different from that without the protrusions 206. If the pitch is more than 5 mm, the compact 2 01 When the molded products 201 come into contact with each other or when the molded product 201 comes into contact with the guide of the transfer line, contact is likely to occur at a part other than the convex portion 206 of the molded product 201. In other words, the frictional resistance is no different from the case without the convex portion 206. The pitch in the case where the protrusions 206 are irregularly formed means that, when focusing on a certain protrusion 206, the pitch around the protrusion 206 and the periphery of the protrusion 206 is as follows. The distance between each existing convex part is measured, this operation is performed for many convex parts 206, and the obtained distance is averaged.

The total area of the projections 206 in the molded body 1 in plan view is 0.5 to 40% with respect to the outer surface area of the molded body 201, and preferably:! -30%, more preferably 5-25% (this value is hereinafter referred to as a convex area ratio). Generally, when the molded body comes into contact with the guide or when the curved surface of the molded body comes into contact with the curved surface, the contact area is limited to a small area. In this case, it is necessary that the pitch of the projections 206 is small and that the projections 206 are present at the contacting portions. Therefore, if the area ratio of the projections is less than 0.5%, the pitch of the projections 206 becomes relatively larger than the size of the projections 206, and the area other than the projections 206 is formed. And the frictional resistance is the same as when there is no protrusion 206. On the other hand, when the planar portions of the molded body 201 come into contact with each other, a small area of the convex portion 206 is effective in reducing the contact area. Therefore, when the convex area ratio is 40% or more, the effect of reducing the contact area is reduced, and the frictional resistance is the same as when there is no convex 6.

The height of the projections 206 does not become a particularly significant factor in preventing the compact 210 from being clogged or caught on the transport line, and the individual areas, pitches and projections of the projections 206 are not particularly large. If the area ratio is within the above-mentioned range, the clogging and catching can be effectively prevented even if the projections 206 are extremely low. Specifically, if the height of the convex portion 206 is 0.01 mm or more, particularly 0.05 mm or more, the clogging is performed. Rolling and snagging can be effectively prevented. There is no particular upper limit on the height of the convex portion 206, but if it is too high, the appearance of the molded body 201 may be impaired, or molding of the molded body 201 may be difficult. The upper limit is about mm.

The molded body 201 can be molded by a conventionally known pulp molding method. In order to form a large number of projections 206 on the body 203 of the molded body 201, for example, the correspondence of the body 203 to the mold surface used for the molding of the molded body 201 and the forming surface thereof A multi-hole plate (punch plate) or the like in which a large number of through-holes having a predetermined diameter are regularly formed may be arranged at the site.

In particular, pulp fibers are deposited on the papermaking surface of a mold that is composed of a set of split molds and has a cavity of a predetermined shape inside to form a water-containing molded body, which can then be expanded and contracted into the molding. Then, a predetermined fluid is supplied into the core to expand the core, and the expanded core is used to expand the molded body on the papermaking surface. Forming the molded body 201 by the pressing method allows the protrusions 206 to be formed with high accuracy, and in particular, the protrusions having a height of 0.01 mm or more can be formed. Is preferred. In this case, the pressing by the core is used for a step of dehydrating the water-containing molded article and / or a step of heating and drying the molded article after dehydration.

The present invention is not limited to the above embodiment. For example, as in the first embodiment, the mold block and the heat-generating block are preferably configured so as to be able to be divided into a plurality in the longitudinal direction, but depending on the size and shape of the molded body, etc. Either or both can be composed of one block. Also, the pattern formed from the set of exhaust holes may be arranged in a lattice, stripe, dot, wave, dashed pattern, or the like, depending on the size and shape of the molded article to be dried. it can. Also, the collective exhaust passage provided inside the mold block can be penetrated so as to open above and below the mold block. It can also be penetrated so as to open at one of the following. In addition, by changing the size of the exhaust portion pattern and the size of the exhaust hole 21, a pattern formed from a set of exhaust holes can be used as a logo, a pattern, and the like.

Further, instead of disposing the heating means in the heat generating block, the heating means can be disposed inside the mold block. Also, the collective exhaust path is not limited to this embodiment, but can be configured to correspond to the pattern of the exhaust section. In this case, the mold block can be divided in the thickness direction in order to facilitate the processing and maintenance of the collective exhaust passage.

In addition, the cross-sectional shape of the exhaust hole in the storage section can be rectangular, elliptical, or oval. In this case, the open area ratio is treated as the hole shape as viewed from the surface in contact with the compact.

In the first and second embodiments, two drying dies are used in abutting relationship.However, depending on the shape of the molded body, only one drying die or a combination of three or more drying dies may be used. Can also.

Further, the steam escape groove 112 formed in the surface of the concave portion 111 may have various patterns according to the shape of the molded article to be dried.

In addition, depending on the shape of the molded article to be dried, the cavity plate 110 of the drying mold 1 may have a convex portion 11 that can be fitted with the molded article to be dried as shown in FIG. The protrusion 1 1 ′ may be used, and a vapor escape groove 1 12 may be provided on the surface of the protrusion 11 1 ′.

Further, instead of disposing a heating means on knock plate 120, a heating means may be disposed on cavity plate 110.

Further, the shape of the hole 131 in the porous metal plate 130 may be a square, an ellipse, or a slit shape, and the size of the hole 131 may be different on the front and back of the porous metal plate 130. good. The opening area ratio in that case was viewed from the surface where the molded body was in contact. Handle with hole shape. The equivalent diameter when the cross-sectional shape of the exhaust hole is other than circular is

(Open area Exhaust hole circumference) X 4 The processing of the perforated metal plate 130 may be cutting.

Further, in the above embodiment, two drying dies are used in abutment, but depending on the shape of the molded article, one drying die alone or a combination of three or more drying dies may be used.

In a preferred embodiment of the present invention, the porous metal plate has a thickness of 0.1 to 10 mm, a hole diameter of 0.05 to 2 mm, and a pore area ratio of 0.5 to 70%. Type.

In addition, the shape of the convex portion 206 of the pulp molded article according to the embodiment is circular when viewed in plan. Instead, the shape in plan view may be a polygon such as a triangle, a rectangle, or a hexagon. May be used.

Further, in the above-described embodiment, each of the protrusions 206 has an independent dot shape, but may have a shape of a ridge or the like instead. Further, in the above-described embodiment, the convex portion 206 is formed on the body portion 203. However, a large number of convex portions may be formed on the bottom portion 204 instead or together with this. In this case, the shape, arrangement, and the like of the convex portion formed on the trunk portion 203 and the convex portion formed on the bottom portion 204 may be the same or different. Further, in the above-described embodiment, the convex portion 206 is formed over substantially the entire region of the trunk portion 203. Instead, a convex portion is formed intermittently on the trunk portion 203. You may. Further, depending on the use and shape of the molded body 201, a convex portion may be formed on the entire surface of the molded body 201, or a convex portion may be formed on a portion other than the body portion 203 and the bottom portion 204. A part may be formed.

Further, the pulp molded article of the present invention can be applied to various shapes such as a box-shaped carton-shaped container, a spoon, a lid, and a stone box, in addition to a pot-shaped hollow container. Hereinafter, the present invention will be described in more detail with reference to examples.

(Example 1 and Comparative Example 1)

Using the drying molds shown in FIGS. 9 and 10, a molded body produced by the pulp molding method was heated and dried by the method shown in FIG. 8 (Example 1). Further, in Example 1, the steam escape groove 1 1 1 was not formed, and only the steam escape hole 1 1 4 (hole diameter 1 mm, pitch 1 O mm) and the through hole 1 1 5 were formed, and a porous metal plate was used instead. The same operation as in Example 1 was performed except that a copper net was used (Comparative Example 1). In both Example 1 and Comparative Example 1, the initial water content of the molded article used was 77% by weight. The details of the drying conditions of Example 1 and Comparative Example 1 and the moisture content of the dried compact are shown in Table 1 below.

Tab.l Example 1 Comparative Example 1 Aluminum punch metal

Pore diameter: 0.6 nun

Hole bite; length 0.9 mm

Perforated plate 1.2 mm wide, 30 mesh copper

Open area ratio: 29%

Thickness; 0.5 mm

Holes are staggered. Width: 2 ；

Depth; 3 咖 without groove

Steam: f-groove hitch; length 5 mm

Contact rate with punch metal; 36% Heater temperature; 194 ° C Heater 194 ^e C

Actual value on dry punch metal; 182. C Observed value on net; C

Pressing force by elastic body; 0.4 MPa Pressing force by elastic body; 0.4 MPa Heating time: 30 seconds Heating time: 30 seconds Molded body Water content: 12.2% by weight Water content: 32.2% by weight As is evident from the results shown in Table 1, Example 1 using a drying mold in which a number of vapor escape grooves were formed in the surface of the concave portion and a perforated metal plate was arranged so as to be in close contact with the surface. In Fig. 7, it can be seen that the surface temperature of the porous metal plate is high and the heat transfer efficiency is high. It can also be seen that the moisture content of the compact after drying is low and the escape of steam is good. And, since the heat transfer efficiency is high and the steam escape is good, it can be seen that the drying efficiency of the compact is high.

On the other hand, in Comparative Example 1 using the drying type in which the steam escape groove is not provided and the net is arranged, the surface temperature of the net is low and the heat transfer efficiency is low. It can also be seen that the moisture content of the compact after drying is high and the escape of steam is poor. Further, since the heat transfer efficiency is low and the escape of steam is poor, it can be understood that the drying efficiency of the compact is low.

(Examples 2 to 5 and Comparative Example 2)

The bottle-shaped molded body shown in Fig. 14 was manufactured by the pulp molding method. <Many hemispherical projections were regularly formed on the body of this molded body. Table 2 shows the area, arrangement pitch, and area ratio of the projections in plan view.

Tab.2

Height direction in plan view Lateral direction

Convex area ratio Friction coefficient Scratch resistance Convex area Pitch Pitch

(Lot2) (mm; dm) (¾)

Example 2 0.283 1.1 0.9 29 0.77 No surface damage Example 3 0.126 0.69 0.8 23 0.71 No surface damage Example 4 0.071 0.26 0.6 23 0.67 No surface damage Example 5 0.031 0.35 0.4 23 0.78 No surface damage Comparative Example 2 0.785 10 10 0.8 0.85 Surface scratched Comparative Example 3 0 0.85 Surface scratched (Comparative Example 3)

A port-like molded body was manufactured in the same manner as in Example 2 except that no convex portion was formed on the body.

(Performance evaluation)

With respect to the molded bodies obtained in the examples and comparative examples, the friction coefficient of the molded body surface was measured by the following method, and the scratch resistance was evaluated. The results are shown in Table 2.

(Method of measuring friction coefficient)

A 10 × 50 mm test piece was cut from the body of the bottle-shaped molded body and fixed to a measuring stand. While applying a point pressure to the test piece with a 20 g pole indenter, the pole indenter was slid at a moving speed of 50 Omm / min, and the load at that time was measured. The friction coefficient was calculated by dividing the load (g) by the weight (20 g) of the pole indenter.

[Evaluation method for scratch resistance]

The bottle-shaped compacts were held in both hands and rubbed while applying a load of about 200 to 300 g, and the scratches generated on the surface were observed.

As is evident from the results shown in Table 2, the molded article of the example has a convex area having a specific area and a pitch formed with a specific area ratio of the convex section, and is therefore smaller than the molded article of the comparative example. It can be seen that the frictional resistance has been reduced. Also, it can be seen that the molded article of the example is less likely to be damaged than the molded article of the comparative example, and that the damage is less noticeable.

Industrial applicability

ADVANTAGE OF THE INVENTION According to this invention, both the escape efficiency of steam and the heat supply to a molded object are favorable, and the drying die of a pulp mold molded object with high drying efficiency is provided.

Further, according to the present invention, there is provided a dry mold for a pulp molded article which is inexpensive and excellent in maintainability.

ADVANTAGE OF THE INVENTION According to this invention, the clogging and the pulp A single molded body is provided.

Further, according to the present invention, there is provided a pulp molded article that is hardly scratched and hardly noticeable.

Claims

The scope of the claims

1. In a dry mold for a pulp molded article used for drying a wet molded article formed by a pulp molding method, a mold block having an accommodating portion corresponding to the outer shape of the molded article is provided. A portion having a large number of fine exhaust holes in the housing portion, a portion in which a collective exhaust passage leading to the exhaust holes is provided inside the mold block, and the collective exhaust passage. A dry mold of a pulp molded article, characterized by having a portion where no is disposed.

2. The drying mold for a pulp molded article according to claim 1, wherein the exhaust hole is formed so as to divide the storage portion into an exhaust portion and a heat transfer portion.

3. The dry mold for a pulp molded article according to claim 1, wherein a diameter of the exhaust hole is 0.1 to 1 mm, and a depth of the exhaust hole is 1 to 10 mm. .

4. The dry mold for pulp molded articles according to claim 1, wherein the diameter of the exhaust hole is increased toward the opening end on the storage section side.

5. The drying mold for a pulp molded article according to claim 1, wherein the exhaust holes are arranged in a stripe, lattice, dot, or wavy pattern.

6. The dry mold for a pulp molded article according to claim 1, wherein the exhaust hole is partially formed in the housing portion.

7. It has a concave or convex portion that can be fitted to the wet molded product formed by the pulp molding method, and a large number of vapor escapes are provided on the surface of the concave or convex portion. A dry mold of a pulp molded article in which a groove is formed and a perforated metal plate is arranged in close contact with the surface.

8. The cavity plate and the lower surface of the cavity plate Having a back plate and

The concave portion is recessed on the upper surface side of the cavity plate, or the convex portion is protruded,

8. The dry mold for a pulp molded article according to claim 7, wherein a heating means is provided on the cavity plate or the back plate.

9. Numerous pulp molding de moldings der connexion convex portions are formed at a predetermined position, in the individual areas of the convex portion in plan view 1. 9 X 1 0 one ³ ~ 3. ² mm 2 A pulp molded article having a pitch of 0.1 to 5 mm and a total area of the projections of 0.5 to 40% with respect to an outer surface area of the pulp molded article.

10. The pulp molded body is a bottle-shaped hollow container having a mouth, a neck, a body, and a bottom, and the protrusion is formed on the body, the Z, or the bottom. 9. The pulp molded article according to item 8.

11. The molded pulp molded article according to claim 9, wherein the height of the convex portion is 0.01 to 1 mm.