JP3289017B2 - Dry mold for pulp mold - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drying mold for drying a wet molded product formed by a pulp molding method.

[0002]

2. Description of the Related Art A drying die used for drying a wet molded product formed by a pulp molding method has a ventilation passage for discharging steam out of the die. Have been. Various types are known as a drying type having such an air passage. For example, (1) those using a porous mold material as described in JP-A-8-260400, (2) those having a net formed on the surface of the porous mold material, and (3) Japanese Patent No. 2,579,875. As described above, there is a type in which a core vent is arranged in a mold exhaust path.

[0003] However, in the dry type (1), since the inside of the mold is formed with minute voids, the passage resistance of steam is large and the escape of steam is not large. In addition, pulp fibers are likely to adhere to the mold material and cause clogging, which requires a great deal of maintenance. Further, the cost of the mold material increases the production cost. In the drying mold of (2), traces of the net are transferred to the surface of the molded body, and the appearance of the molded body is impaired. Further, since the contact between the mold member and the net is a line contact, the heat transfer efficiency is insufficient and sufficient heat supply cannot be performed.
In the dry mold of (3), it takes time to attach and adjust the core vent member to the exhaust path, and it is difficult to attach the core vent to a portion having a small curvature or a thread portion. In addition, traces of the outer contour of the core vent member remain on the surface of the molded product, which is not preferable in appearance.

[0004] Accordingly, an 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.

[0005]

SUMMARY OF THE INVENTION The present invention is directed to a drying mold for a pulp molded article used for drying a wet molded article formed by a pulp molding method. A mold block having a plurality of fine exhaust holes in the housing portion, and a portion in which a collective exhaust passage leading to the exhaust hole is provided inside the mold block. Propelled by one a site collecting exhaust passage is not provided, the exhaust hole, the yield
A predetermined pattern is set so that the compartment is divided into an exhaust section and a heat transfer section.
Turn is drilled, the collective exhaust path is provided
The above object has been attained by providing a dry mold of a pulp molded article, characterized in that the exhaust hole is not formed in a portion not provided.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described based on preferred embodiments with reference to the drawings. FIG. 1 shows an 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 molds 1 are used as a pair, and are used for drying a cylindrical bottle-shaped molded body having a mouth and a neck.

As shown in FIG. 1, a drying mold 1 includes a mold block 2 having a housing portion 20 corresponding to the outer shape of a molded body.
It has. The accommodating portion 20 has a large number of fine exhaust holes 21 and the inside of the mold block 2 has the exhaust holes 2.
1 has a portion where the collective exhaust passage 22 is provided and a portion where the collective exhaust passage 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 thereof. The upper surface of the peripheral portion of the housing portion 20 is flat, and the upper surface is a dividing surface (butting surface) of the drying mold 1.
Becomes

The diameter D of the exhaust hole 21 (the distance from the surface of the housing in the exhaust portion to the collective exhaust passage, see FIG. 2B)
Makes it easy for steam to escape and prevents clogging by pulp fibers. Furthermore, from the viewpoint of durability and processability of the exhaust hole 21,
0.1 to 1 mm, preferably 0.2 to 0.8
mm is more preferable. Further, the depth d of the exhaust hole 21 (see FIG. 2B) is 1 in terms of easiness of escape of steam, prevention of clogging by fibers, and easiness of maintenance.
It is preferably from 10 to 10 mm, more preferably from 2 to 8 mm. Here, the depth of the exhaust hole 21 refers to the distance from the storage section 20 to the collective exhaust path 22. Exhaust hole 2
The ratio d / D of the hole diameter D to the depth d of 1 is 0.5 to 15 in view of 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 more preferably 3 to 10.

The exhaust hole 21 is formed in a manner that the opening area ratio of the exhaust hole 21 in the accommodation portion 20 and the exhaust hole 2 are increased in view of the balance between the ease of vapor escape and the thermal conductivity and the securing of the strength of the accommodation portion 20.
The pitch of 1 can be appropriately determined.

The exhaust hole 21 is provided in the housing portion 20.
Part 23 and exhaust hole 21 formed unevenly at high density
Are bored in the pattern such that divided into a heat transfer section 24 roast Gana. The boundary between the exhaust portion and the heat transfer portion, specifically, collectively in patterns defined by the outermost connecting it contour outer edge each other of the exhaust holes of the exhaust hole 21 drilled in the housing portion 20, forming Drying by heat supply to the body is mainly performed through the heat transfer unit 24 where the collective exhaust passage 22 is not provided, but heat transfer is also performed from a portion other than the exhaust holes 21 in the exhaust unit 23.

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 1/19 from the viewpoint of the balance between the ease with which steam can escape and the thermal conductivity. ~ 1 /
It is preferably 1. The width of the exhaust portion 23 (the interval between the adjacent heat transfer portions 24) is preferably 1 to 20 mm, more preferably 2 to 15 mm,
More preferably, it is 4 to 10 mm. If the width of the exhaust portion 23 is too large, heat transfer in the exhaust portion 23 becomes insufficient and drying unevenness occurs. If the width is too narrow, the exhaust portion 23 and the corresponding collective exhaust passage become large or complicated. In addition, the mold becomes complicated, and the mold strength cannot be secured. For a reason opposite to the width of the exhaust unit, the width of the heat transfer unit 24 (the interval between the adjacent exhaust units 23) is 5 to 50 mm.
Is preferably 8 to 40 mm, more preferably 10 to 30 mm.
Regarding the relationship between the width of the exhaust portion 23 and the depth of the exhaust hole 21, (the width of the exhaust portion 23) / (the depth of the exhaust hole 21) is 5 or less from the viewpoint of heat transfer in the exhaust portion 23. Preferably, it is 4 or less, more preferably, 3 or less. In the present embodiment, the mouth of the molded body,
Exhaust holes 21 are formed in a portion corresponding to the central portion of the torso in a row pattern at a predetermined interval therearound, and in a portion corresponding to the shoulder and the lower portion of the torso in a ring-shaped pattern. ing. In this embodiment, as shown in FIG. 2A, the individual exhaust holes 21 forming each pattern are formed adjacent to each other in a staggered pattern. As described above, the accommodation portion 20 is separated from the exhaust portion 23 and the heat transfer portion 2 by the drilling pattern of the exhaust hole 21.
By dividing into three, a large number of exhaust holes 21 can be gathered in one collective exhaust passage 22, and efficient exhaust is possible even if there are few collective exhaust passages that are difficult to process. It is preferable that the exhaust portion is provided with the exhaust hole 21 so that the area ratio in the accommodation portion 20 is 5 to 50% from the viewpoint of the balance between the ease of escape and the thermal conductivity and the strength of the accommodation portion 20. . In particular, drilled vents 21 from opening ratio of the exhaust portion when the array of exhaust holes 21 was staggered (sequence exhaust hole 21 is located at the apex angle of the regular triangle), the intensity point It is necessary to secure the pitch P at least twice the hole diameter D. Therefore, the opening ratio of the exhaust portion in the case of the staggered lattice shape is 22.7% at the maximum from Expression (1), and the exhaust hole 21
Is preferably 1.1 (22.7 × 5) to 11.3 (22.7 × 5) from the area ratio described above.
0)%.

[0014]

(Equation 1)

As shown in FIG. 2B, the exhaust hole 21 is
It is preferable that the hole diameter D is formed so as to increase toward the opening end on the accommodation section 20 side. Thereby, the edge 21a of the opening edge becomes gentle, clogging of the pulp fiber hardly occurs, and maintenance is easy. The exhaust hole 22 can be formed by electron beam processing, laser beam processing, or the like. When drilling the exhaust holes 22, collective exhaust is performed from the side of the accommodation portion 20 that contacts the molded body.
Preferably, it is drilled toward the airway 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. The exhaust holes 21 are formed 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 includes 22A to E and 25B,
25D.

The cross-sectional area (cross-sectional area in the length direction) of the collective exhaust passage 22 is preferably 30 to 400 mm ² ,
More preferably, it is 0 to 300 mm ² . If the cross-sectional area is small, the exhaust resistance increases, and processing becomes difficult. On the other hand, if it is too large, the heat capacity of the block will decrease,
The stability of the block heat supply is reduced.

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 on a lower surface side of the mold block 2 by a predetermined means. 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 (not shown) such as an electric heater can be inserted into the through hole 30. There is something. When the heating means is provided in the heat generating block 3, by sharing the heat generating block with another dry type heat generating block according to the shape of the molded body, the mold parts can be shared and the production cost of the mold can be reduced. In addition, it is possible to easily change the mold.

In the drying mold 1 of this embodiment, the mold block 2 can be divided into five blocks 2A to 2E in the longitudinal direction, and each block can be fixed by a predetermined fixing means. . By configuring the mold block with a plurality of blocks in this manner, processing 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 is provided so that five collecting exhaust passages 22A communicating with the exhaust holes 21A surround the accommodating portion 20A. ing. Block 2 shown in FIGS. 1 and 4
B is a block corresponding to the shoulder of the molded body, and an exhaust hole 21B having a ring-shaped pattern is formed in the accommodation portion 20B.
These exhaust holes 21B communicate with a collective exhaust passage 22B in a wide space. The block 2B includes a collective exhaust passage 22.
Ru through valve exhaust passage 22C of the B and below the block 2C
Exhaust passage 25B is bored. A 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 a row pattern at a predetermined interval in the accommodating portion 20C. Are connected to the five collective exhaust passages 22C for each row. 1 and 6
The block 2D shown in FIG.
D is drilled in the housing portion 20D, and these exhaust holes 21D communicate with a collective exhaust passage 22D in a wide space. Further, the block 2D, the exhaust passage 25D which Ru through valve exhaust passage 22C of the joint exhaust passage 22D and block 2C is bored. A block 2E shown in FIGS. 1 and 7 is a block corresponding to the bottom of the molded body. Exhaust holes 21E are drilled in a row pattern corresponding to the bottom of the housing portion 20E. Exhaust passage 22E in a large space
Leads to. Block. 2E, also, the block leads to a 2D collecting exhaust passage 22D, the exhaust passage 25E to face before Sharing, ABS air path 25D is bored. And
The collective exhaust passage 22E and the exhaust passage 25E communicate with the exhaust chamber 26E, and communicate from the exhaust chamber 26E to an exhaust port 27E formed at the lower end of the block 2E.

The drying molds 1 of the present embodiment are used in pairs, and in a state in which a molded body in a wet state is accommodated in a cavity formed by two accommodating portions, the divided surfaces are abutted on each other to form the molded body. Is dried.

Next, a preferred method for drying a molded article 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 mold are simplified for simplicity. First, as shown in FIG. 8A, the divided surfaces of the two drying dies 1 and 1 were abutted against each other to be molded into a cavity formed by the two storage portions 20 by a predetermined papermaking method. The pulp molded article 4 is accommodated. The two drying dies 1 are preheated to a predetermined temperature by the heating element arranged on the mold block 2.

Next, as shown in FIG. 8B, a 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 made of urethane, fluorine-based rubber, silicone-based rubber, elastomer, or the like having excellent tensile strength, rebound resilience, and elasticity.

Next, as shown in FIG. 8C, a pressurized fluid is supplied into the core 5 to expand the core 5, and the molded body 4 in a wet state is accommodated by the expanded core 5. 20 on the inner surface. The molded body 4 is pressed against the inner surface of the housing portion by the expanded core 5, and the drying of the molded body 4 proceeds, and the inner surface shape of the housing portion 20 is transferred to the molded body 4. As described above, since the molded body 4 is pressed against the housing from the inside of the molded body 4 to the outside, even if the inner surface shape of the housing is complicated, the molded body 4 is dried with high drying efficiency, and The inner surface shape of the storage section 20 is accurately transferred to the molded body 2. Further, by setting the diameter of the exhaust hole 21 formed in the housing portion 20 within the above-described range, the surface of the housing portion 20 of the drying mold 1 is less likely to be deformed by the pressing by the core 5. Examples of the pressurized fluid used to expand the core 5 include compressed air (heated air), oil (heated oil),
Other various liquids are used. The pressure for supplying the pressurized fluid is 0.01 to 5 MPa, particularly 0.1 to 3 MPa.
It is preferred that

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

As described above, the drying mold 1 of the present embodiment has good steam escape efficiency and good heat supply to the compact.
High drying efficiency. In particular, since the accommodating portion 20 is divided into an exhaust portion and a heat transfer portion by the exhaust holes 21 formed in a predetermined pattern, drying can be performed efficiently even with a small number of collective exhaust passages. That is,
Since the number of the collective exhaust passages is small, the heat conducting portion is large, sufficient heat supply is possible, and the heat capacity is large, so that the temperature stability of the drying mold is high. Further, since minute exhaust holes 21 are densely formed in the collective exhaust passage, the exhaust efficiency is very high. Further, since the mold block 2 can be divided in the longitudinal direction, maintenance work such as cleaning can be easily performed.

The present invention is not limited to the above embodiment. For example, 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 as in the present embodiment, but depending on the size and shape of the molded body, one or both of them may be used. It can also be composed of one block. In addition, the pattern formed from the set of exhaust holes should be arranged in a pattern such as a lattice, a stripe, a dot, a wave, a wavy line, a broken line, etc., according to the size and shape of the molded body to be dried. Can also. Further, the collective exhaust passage provided inside the mold block can be penetrated so as to open above and below the mold block, or can be penetrated so as to open at one of the upper and lower sides. Also, by changing the pattern of the exhaust portion 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 may be disposed inside the mold block. Further, the collective exhaust path is not limited to this embodiment, and can be configured to correspond to the pattern of the exhaust unit. In this case, the mold block can be divided in the thickness direction in order to facilitate processing and maintenance of the collective exhaust passage.

Further, the cross-sectional shape of the exhaust hole in the storage section may be rectangular, elliptical, or oval. In this case, the open area ratio is treated as a hole shape viewed from the surface in contact with the molded body. When the cross-sectional shape of the exhaust hole is other than circular, the equivalent diameter is a value converted by (opening area / perimeter of exhaust hole) × 4. Further, the processing of the porous metal plate 130 may be a cutting processing.

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 can be used.

[0031]

According to the present invention, there is provided 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.

[Brief description of the drawings]

FIG. 1 is a schematic view showing an embodiment of a drying mold of a pulp molded article of the present invention, wherein (a) is a plan view and (b) is a front view.

FIG. 2 is a diagram showing a main part of a drying mold according to the embodiment;
(A) is an enlarged plan view of an accommodation part, (b) is an enlarged sectional view of an accommodation part.

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

FIG. 4 is an end view (an end view equivalent to the arrow bb in FIG. 1) of a block constituting the dry mold block of the embodiment.

FIG. 5 is a cross-sectional view (corresponding to a cross-sectional view taken along the line cc in FIG. 1) of a block constituting the dry mold block of the embodiment.

FIG. 6 is an end view (an end view corresponding to the arrow dd 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 ee in FIG. 1) of a 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, wherein (a) is a view showing a state in which the molded article is stored;
(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.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Drying type 2 Die block 20 Housing part 21 Exhaust hole 22 Collective exhaust path 23 Exhaust part 24 Heat transfer part

──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Toshio Kobayashi 2606 Kabane-cho, Akaga-cho, Haga-gun, Tochigi Prefecture Inside Kao Co., Ltd. References JP-A-2000-34699 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) D21J 3/00-7/00

Claims (4)

(57) [Claims] 1. A dry mold for a pulp molded article used for drying a wet molded article formed by a pulp molding method, comprising a mold block having a housing portion corresponding to the outer shape of the molded article. The housing has a large number of fine exhaust holes, and a portion where a collective exhaust passage leading to the exhaust hole is provided inside the mold block, and the collective exhaust passage is provided. and a free portion <br/> Contact is, the exhaust hole, said housing portion and the exhaust portion and the heat transfer portion
It is drilled in a predetermined pattern so that it is divided into
The exhaust hole is provided at a portion where the collective exhaust passage is not provided.
A dry mold for a pulp molded article, characterized in that no pulp is formed. 2. The dry mold for a pulp molded article according to claim 1, wherein the diameter of the exhaust hole is 0.1 to 1 mm, and the depth of the exhaust hole is 1 to 10 mm. 3. A dry-type pulp molded article according to claim 1 or 2 is increased in diameter toward the open end of the pore size of the exhaust holes the housing part side. 4. The method according to claim 1, wherein the exhaust holes are striped, lattice-shaped, dot-shaped,
Drying type pulp molded article according to any one of claims 1 to 3 which is formed in the wavy pattern.