JP3519210B2 - Mold for after press of pulp fiber molding - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a forming die and an after-pressing method for applying an after-press when producing a pulp fiber molding from pulp slurry.

[0002]

2. Description of the Related Art When a predetermined product or the like is transported, the product or the like is packed by a packaging / cushioning material having a recess corresponding to the shape of the product or the like. Foamed polystyrene and the like are usually used as such packaging and cushioning materials, but these have recently become a major problem in causing environmental pollution upon disposal.

On the other hand, pulp fiber molding called pulp mold is made from pulp (paper-making raw material) fibers obtained from waste paper such as corrugated cardboard and newspaper for easy use of recovered resources. A body is manufactured, and such a pulp fiber molded body is used as a packaging material with less environmental pollution. Such a pulp fiber molded body usually uses a papermaking mold having a base material having a surface of a shape corresponding to that and having a large number of suction holes opened on the surface thereof, and the papermaking mold is a pulp slurry. It is formed by sucking from the suction hole in the state of being immersed in the tank and adsorbing the pulp fiber on the surface of the base material or on the adsorption surface composed of a mesh provided on the surface of the base material, outside the pulp slurry tank. By further suctioning and dewatering the adsorbed pulp fiber molded body to obtain a water content that allows the shape to be maintained, and then releasing from the papermaking mold and further drying with hot air in a drying furnace. Manufactured by.

[0004]

By the way, in the pulp fiber molded body manufactured as described above, the surface on the side of the recess for fitting the material to be packed such as a product, that is, the surface is adsorbed by the papermaking mold. Since it is in contact with the suction surface at this time, it is formed with a relatively high shape, size, and surface accuracy (hereinafter, simply referred to as accuracy) following the shape of the suction surface. On the other hand, the back surface which is not in contact with the suction surface at the time of suction is formed with relatively low accuracy because large unevenness is generated due to nonuniformity of the suction amount and density of pulp fibers. Also,
Generally, when a pulp fiber molded body is dried, deformation may occur due to nonuniformity of drying shrinkage. Therefore, when a highly accurate pulp fiber molded body is desired,
So-called after-pressing is performed in which pressure is applied from both sides with a pair of molding dies each having a molding surface having a shape corresponding to a desired pulp fiber molded body.

However, in order to obtain a pulp fiber molded body having a desired uniform thickness, the pair of molding dies for performing the after-pressing have molding surfaces formed with relatively high dimensional accuracy. Therefore, when the pair of molding dies are separated from each other after the pressurization is completed, the pulp fiber molded body is brought into close contact with the molding surface of one of the molding dies, and the mold releasing work from the molding dies becomes difficult. There was a problem. Moreover, since this mold releasing work is generally performed manually by the operator, when performing afterpressing, heating is performed at the same time as pressurization in order to facilitate deformation following the molding surface of the pulp fiber molded body. When this is done, there is a possibility that an operator is likely to get burned due to time-consuming demolding.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a molding die for an afterpress and an afterpressing method which facilitate the releasing work after pressing. is there.

[0007]

[Means for Solving the Problems] In order to achieve such an object, the gist of a molding die for afterpressing of the first invention is that a pulp fiber molding formed from pulp fibers in pulp slurry. In order to pressure-mold into a predetermined shape, an after-pressing mold having a molding surface formed in a shape corresponding to one of the front surface and the back surface of the pulp fiber molded body having the predetermined shape, to inject air from a) the forming surface, seen including a plurality of air injection holes which open at one end on at least one of the recesses of the corners and predetermined small opening width of the forming surface, the plurality of Each of the air injection holes
The openings on the molding surface side of the
It consists of a number of slit holes .

[0008]

According to the first aspect of the invention, the after-press molding die has one end at least at one of the corner of the molding surface and the recess having a predetermined small opening width in order to inject air from the molding surface. Is configured to include a plurality of air injection holes that are open. Therefore, when the pulp fiber molded body is released from the molding surface of the afterpress molding die after the completion of pressurization, the pulp adhered to the molding surface by injecting air from the plurality of air injection holes. The fiber molding can be separated from the molding surface. Therefore, as compared with the conventional after press molding die, which requires manual release of the pulp fiber molded product from the close contact state because the air injection hole is not provided, the mold releasing work can be performed easily. A mold for afterpress that can be performed is obtained. The corners of the mold and the recesses having a small opening width are relatively hard to be deformed corresponding to the corners and the protrusions having a small width of the pulp fiber molded body, and therefore the deformation due to the air injection hardly occurs. Further, the air injection hole does not necessarily have to be provided in both of the pair of molds for pressurizing the pulp fiber molded body from both sides, and when the pair of molds are separated from each other, the molding of one mold is always performed. When the pulp fiber molded body is brought into close contact with the surface, it is sufficient if only one of the molding dies is provided. Moreover, according to the first invention,
Openings on the molding surface side of each of the plurality of air injection holes
Consists of a plurality of slit-shaped holes arranged in parallel along one direction.
Since the slit-shaped holes are pulp,
Since it is relatively inconspicuous even if it is formed into a fiber molded body,
Of the fiber molded body without significantly impairing its appearance.
The air injection amount is increased by making the opening area of the air ejection hole relatively large.
It is possible to increase the number of molds and to further facilitate mold release.

[0009]

[Other Aspects of the First Aspect of the Invention] Here, it is preferable that the recess having the predetermined small opening width has, for example, a width of about 3 to 30 (mm) and a depth.
It has a dimension of about 10 (mm) or more. That is,
The predetermined small opening width is preferably in the range of 3 to 30 (mm). Width 3
In the portion of (mm) or less, it is difficult to form an air injection hole while maintaining a predetermined molding surface shape, and in the portion of 30 (mm) or more, at the top of the convex portion of the pulp fiber molded body during air injection. This is because the flat portion provided is deformed.

Preferably, the air injection hole has a size of, for example, φ 0.5 to 30 (mm), for example, 1/9 to 1 /
The density is preferably about 20000 (pieces / mm ² ). In order to inject a sufficient amount of air for releasing the pulp fiber molded body, it is preferable that the size is φ0.5 (mm) or more, and in order to make the traces of holes remaining after pressurization inconspicuous. , Φ
This is because a size of 30 (mm) or less is preferable. Further, in the hole of this size, when the density is higher than 1/9 (pieces / mm ² ), the surface roughness of the pulp fiber molded article is significantly reduced,
This is because if the density is lower than 20000 (pieces / mm ² ), the amount of air injected will be insufficient and release will be difficult.

Further, preferably, the afterpress molding die is (b) provided on the back surface side of the molding surface, and the other ends of the plurality of air injection holes are opened and the plurality of air injection holes are opened. It further includes a groove-shaped closed space connected to an air supply port for supplying air to the hole. By doing so, the closed space is partitioned into a groove shape, so that the rigidity of the molding die is enhanced as compared with the case where there is no partition.
The grooved closed space has a width of 3 to 20 (mm) and a depth of 3
It is preferably formed to about 20 (mm).

[0012]

Also, preferably, the groove-shaped closed space occupies less than half of the total area in a cross section passing through the closed space perpendicular to the pressing direction of the pulp fiber molded body. It is formed in. By doing so, since the proportion of the groove-shaped closed space occupied in the cross section perpendicular to the pressurizing direction is made small, when a heater for heating the pulp fiber molded body is provided on the back side of the molding die. In addition, the heat conductivity to the molding surface is relatively high, and the pulp fiber molded body can be heated easily.

Further, preferably, the molding surface is subjected to a surface treatment for enhancing the slipperiness with the pulp fiber molded body. By doing so, the molding surface becomes slippery, and the adhesion between the molding surface and the pulp fiber molded body after the completion of pressurization is lowered, and the mold release is further facilitated. The above-mentioned surface treatment is, for example, to fix a fluororesin layer or a plating layer to the surface of the base material of the molding die to form the molding surface, or to form the base material surface with R _max = 1.
It is processed to have a surface roughness of 00S or less. When the fluororesin is fixed, its thickness is 10 to 800 (μm).
The thickness is preferably about 5 to 200 (μm) when the molding surface is composed of the plated layer.

[0015]

[0016]

[0017]

[0018]

[0019]

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing the essential structure of a pulp fiber molded body manufacturing apparatus to which a molding die for afterpressing according to an embodiment of the present invention is applied. In the figure, a pulp fiber molded body manufacturing apparatus includes a pair of papermaking molds 10a and 10b for molding a pulp fiber molded body 100 from a pulp slurry 96 prepared by a raw material apparatus (not shown) A molding machine 50 having a papermaking mold 10)
A mold release machine 52 for removing the pulp fiber molded body 100 from the papermaking mold 10, a dryer 54 for drying the pulp fiber molded body 100, and an increase in accuracy of the dried pulp fiber molded body 100. The after-press device 60 of FIG.

Papermaking mold 10 provided in the molding machine 50.
Has a suction surface 12 having a shape corresponding to the pulp fiber molding 100 to be molded. For example, the molding surface 1
Adsorption surface 1 formed in the same shape on the surface of the base material made of an aluminum alloy having the surface formed in the same shape as 2
A mesh-like body (not shown) forming 2 is provided so as to cover it. The base material of the papermaking mold 10 is provided with a plurality of suction holes penetrating the base material so that both ends are opened on the front surface and the back surface. The reticulated body is a non-woven fabric such as polyester or polypropylene, a metal mesh such as tricot, stainless steel or brass, a synthetic fiber mesh such as nylon or tetron, and is formed into a shape along the surface of the base material using a press or the like. After being preformed, the mesh holding frame 1 is provided at the peripheral edge.
It is fixed by 4 etc.

The molding machine 50 has a rotating shaft 94 supported by a supporting device (not shown) so as to be rotatable about an axis perpendicular to the plane of the drawing, and the rotating shaft 94 has a pair of supporting arms 22a. , 22b are mounted at rotational angle positions different from each other by 180 °. And those support arms 2
Papermaking dies 10a and 10b are attached to the tips of 2a and 22b, respectively. A pulp sludge tank 98 storing pulp sludge 96 is provided below the rotating shaft 94, and the papermaking molds 10a and 10b attached to the tips of the support arms 22a and 22b, respectively, and the pulp sludge 96 at their lower end positions. It is supposed to be immersed in it. That is, the papermaking molds 10a and 10b are provided on the opposite sides of the rotary shaft 94, and are rotated in the pulp sludge tank 98 so that they are alternately positioned in the pulp sludge 96 in the pulp sludge tank 98. Then, the pulp is adsorbed on the adsorption surface 12 by being sucked from a suction hole (not shown) while being immersed in the pulp sludge 96.
The pulp fiber molded body 10 is sucked and dehydrated outside.
0 is molded.

Further, the mold releasing machine 52 provided above the rotating shaft 94 is movable in the left-right direction in the drawing, and is vertically moved at the left end portion (that is, immediately above the rotating shaft 94) and the right end portion shown by a broken line. A release mold 102 that is movable in the direction is provided. The mold 102 for release is the suction surface 1 of the papermaking mold 10.
Back surface 100 of pulp fiber molded body 100 adsorbed on 2
The receiving surface 58 has a shape substantially corresponding to the shape of d, and a large number of suction holes (not shown) are opened in the receiving surface 58. The mold release machine 52 sucks the pulp fiber molded body 100 on the suction surface 12 at the lower end position lower than the position shown in the figure when the mold for release 102 is at the left end shown by the solid line. While removing from the suction surface 12, at the lower end position of the right end portion shown by the broken line,
The pulp fiber molded body 100 is transferred from the molding machine 50 to the dryer 54 by lowering the pulp fiber molded body 100 onto the carry-in conveyor 56 provided in the dryer 54.

The dryer 54 is provided in a box-shaped container 104 kept at a predetermined temperature by a heat source (not shown).
A plurality of pedestals 10 for mounting the pulp fiber molded body 100
6, an elevating device 108, a conveyor 56 for carrying the pulp fiber molded body 100 toward the elevating device 108, and a dryer for drying the pulp fiber molded body 100 lowered in the box container 104. The conveyor 110 for carrying out from 54 and sending to the next process is provided. The elevating device 108 raises the plurality of platforms 106 from the left side and lowers them from the right side in the figure, and the pulp fiber molded body 10 placed on the platform 106.
0 is dried quickly while being revolved in the box container 104.

The above-mentioned after-pressing device 60 is provided with a pair of molding dies 62 movably provided in the vertical direction of FIG.
a, 62b (hereinafter, unless otherwise specified, simply the molding die 6
2). FIG. 2 is an enlarged view showing a state in which the pulp fiber molded body 100 is subjected to afterpressing by the pair of molding dies 62a and 62b. In the figure, a molding die 62 includes molding surfaces 66a and 66b having shapes corresponding to the front surface 100a and the back surface 100d of the pulp fiber molded body 100, and a base material 68 made of, for example, an aluminum alloy or the like. 68,
A fluororesin layer 7 having a shape that follows the surface 64 of the base material 68 and is provided so as to cover the pulp fiber molded body 100 in order to enhance the slidability with the pulp fiber molded body 100 and has a thickness of, for example, about 10 to 800 (μm).
0, the base material 68 is fixed to one surface, and the base 7 is attached to the tip end portions of the pressure shafts 72, 72 on the other surface side.
4, 74 and the heater 7 fixed to the other surface of the base 74
6, 76 and. In this embodiment, the molding die 62 corresponds to a molding die for afterpressing, and the molding surface 66a,
66b is formed by the surface of the fluororesin layer 70.

The molding surfaces 66a and 66b are the mating surfaces 4 provided on the peripheral portions of the pair of molding dies 62a and 62b.
8 and 48 are in contact with each other (that is, closer to each other than the position shown in the drawing), the pulp fiber molded body 100 after drying is placed between the molding surfaces 66a and 66b. It is formed so that a gap slightly smaller than the thickness is generated. Therefore, the pulp fiber molded body 100 placed on the molding die 62a is pressed between the molding die 62b and the molding die 62b, and has a uniform thickness of about the size of the gap and follows the molding surface 66 satisfactorily. Is formed into a flat surface state.

The back surface 78 of the base material 68 located on the base 74 side is, for example, 10 to 10 along one direction as shown in FIG. 3 in which only the base material 68 is viewed from the back surface 78 side.
Widths of 3 to 20 (m
A plurality of grooves 80 having a depth of approximately m) and a depth of approximately 3 to 20 (mm) are provided. The groove 80 is not continuous with the outer peripheral surface 82 of the base material 68, but is communicated with the adjacent grooves 80 at both longitudinal end portions and the central portion,
Therefore, when the base material 68 is fixed to the base 74, one closed space 84 including a plurality of grooves 80 is formed between them. Further, this groove 80 is, for example,
It is formed at the same time when the base material 68 is cast to form the shape of the surface 64 or the like, but a separately molded block may be assembled with the base, or the base material 68 is difficult to deform. In some cases, it may be formed by cutting after casting. In addition, a plurality of grooves 8 are formed on the back surface 78.
The ratio of 0 as a whole is about 1/2 of the total area of the back surface 78.

Then, both ends of the base material 68 are opened on the front surface 64 and the back surface 78, for example, a diameter of 0.5 to 30.
(mm) about a plurality of air injection holes 86, for example 1/9 to 1 /
It is provided with a density of about 20000 (pieces / mm ² ), but on the back surface 78 side thereof, in the groove 80 (that is, the closed space 8
4), while on the surface 64 side,
The corners and the bottom surface 64a of the predetermined recess are opened. It should be noted that, of the recess bottom surface 64a, the air injection hole 86 is opened only in a recess having a depth of 10 (mm) or more and a small opening width of about 3 to 30 (mm), for example. Is.
The air injection hole 86 is formed, for example, in the fluororesin layer 70.
Is formed and then perforated, and penetrates through the fluororesin layer 70 and is opened in the molding surface 66.

Further, the base 74 is provided with a through hole 88 penetrating in the thickness direction, and the closed space 84 is provided with a switching valve 90 provided in the afterpress device 60 through the through hole 88. It is connected to the compressor 92.
Therefore, the compressor 92 is operated and the switching valve 9
When 0 is in the connection position shown in the drawing, the pressure air sent from the compressor 92 is jetted from the opening of the air jet hole 86 on the molding surface 66 side through the closed space 84. That is, in this embodiment, the through hole 88 corresponds to an air supply port for supplying air to the air injection hole 86.

A method of manufacturing a pulp fiber molded body 100 using the pulp fiber molded body manufacturing apparatus configured as described above will be described with reference to FIG. 1 and FIG. 4 showing a molding process for one papermaking mold 10a. explain.

First, in the dipping step of step 1, the rotating shaft 9
By rotating 4, the papermaking mold 10a located on the upper side is rotated downward and the papermaking mold 10b located on the lower side is rotated upward according to the arrow A in FIG. Next, in the suction step of step 2, during the rotation, suction is started from a suction hole (not shown) of the papermaking mold 10a. Then, by further rotating, the papermaking mold 10a is put into the pulp sludge 96 in the pulp sludge tank 98, so that in the adsorption step of step 3, the pulp in the pulp sludge 96 is held for a predetermined adsorption time. The fibers are adsorbed on the adsorption surface 12. This predetermined adsorption time is, for example, 2
It is set to a relatively short time such as seconds.

After the lapse of the predetermined time, in the pulling up step of step 4, the papermaking mold 10a is taken out of the pulp sludge 96 while continuing the suction from the suction hole, and in the dehydrating step of step 5, for example, about 10 seconds. By further continuing suction for a predetermined time, the pulp fibers adsorbed on the adsorption surface 12 are dehydrated and the pulp fiber molded body 100 is molded.

After the dehydration is completed as described above, in the releasing step of step 6, the releasing die 102 is lowered while being positioned at the left end position thereof, and the papermaking die 10a is inserted through the pulp fiber molding 100. And spraying air from a suction hole (not shown) of the suction surface 12 of the papermaking mold 10a,
Suction is performed from a suction hole (not shown) of the receiving surface 58 of the release mold 102. Then, the mold for mold release 102 is raised while continuing the injection and suction of the air, whereby the pulp fiber molded body 100 is adsorbed to the receiving surface 58 and released from the papermaking mold 10a.

Subsequently, the mold 102 for releasing the pulp fiber molded body 100 adsorbed thereon is lifted to its upper end position,
It is moved to the right in the figure and is lowered again at the right end position indicated by the broken line. In this way, the release mold 102
Is lowered to the lower end position shown in the figure, and then air is jetted from the suction hole, so that the pulp fiber molded body 10
0 is peeled off from the receiving surface 58 and lowered onto the carry-in conveyor 56 of the dryer 54.

Then, in the drying step of step 7, the pulp fiber molded body 10 lowered onto the carry-in conveyor 56.
0 is sequentially fed into the box-shaped container 104 of the dryer 54 and transferred onto the table 106, and the box-shaped container 104 is rotated clockwise in FIG. 3 while being placed on the table 106. . The inside of the box-shaped container 104 of the dryer 54 is maintained at a predetermined temperature as described above. Therefore, during the above-described rotation, the pulp fiber molded body 100 is sufficiently dried to obtain a dried product of the pulp fiber molded body 100 as shown in FIG. At, the transfer conveyor 110 is moved. Incidentally, the residual water content of the pulp fiber molded body 100 after drying is usually 6 to 8
Although it is about (wt%), in this embodiment, the temperature and the drying time are set so that the moisture content after drying is 10 to 15 (wt%).

In the after-pressing step of the following step 8, the pulp fiber molded body 100 conveyed by the carry-out conveyor 110 is the molding surface 66a of the molding die 62a (lower die).
, The heaters 76, 76 are operated and the molding die 62b (upper mold) is lowered, so that the pulp fiber molding 100 is removed from the heater 76 between the pair of molding dies 62a, 62b. With the conduction heat of
It is heated to a temperature of about 100 to 250 (° C) and pressed at the same time. As a result, the pulp fiber molded body 100 molded into a desired shape and thickness is obtained by following the shape of the gap formed between the molding surfaces 66a and 66b.

At this time, as described above, since the residual water content of the pulp fiber molded body 100 is relatively large at about 10 to 15 (wt%), the residual water content can evaporate as described above. When heated to a temperature of ~ 250 (℃),
Moisture in the pulp fiber molded body 100 is evaporated. Therefore, the residual moisture content of the pulp fiber molded body 100 is reduced to 6 to 8 (wt%) after ordinary drying, while the pulp fiber molded body 100 and the molding surface 66 of the molding die 62 are separated from each other. , A water vapor layer is formed.

When the above-mentioned pressurization and heating are continued for a predetermined time of, for example, about 3 to 10 seconds to complete the molding of the pulp fiber molding 100, the molding dies 62a and 62b are separated from each other. At this time, for example, 1 to 3 after the rising of the molding die 62b (upper die) (or the lowering of the molding die 62a) is started.
After a short time of about a second, the compressor 92 on the molding die 62b side is operated and the switching valve 90 is switched to the connecting position shown in the drawing, so that the pressure air is ejected from the air ejection hole 86 of the molding die 62b. To be Therefore, the pulp fiber molded body 100 is left on the molding die 62a without being pulled up by the molding die 62b while being in close contact with the molding surface 66b. The above-mentioned pressure air injection is performed at a pressure of, for example, about 0.5 to 5 (kgf / cm ² ).
It is performed for about 3 seconds.

After the separation between the molding dies 62a and 62b is completed, the compressor 92 on the molding dies 62a side is operated and the switching valve 90 is switched to the connecting position shown in the drawing, so that the air of the molding dies 62a is turned on. Injection hole 86
From which pressurized air is jetted. The air pressure and the injection time at this time are the same as in the case of the molding die 62b.
As a result, the pulp fiber molded body 100 that has been in close contact with the molding surface 66a of the molding die 62a is not deformed at all, and the pressure due to the jet of compressed air and the fluororesin layer 70 and the water vapor layer formed on the surface Due to the high slipperiness, it can be easily lifted from the molding surface 66a. Then, the after-pressing step of step 8 is completed by picking up the pulp fiber molded body 100 on the molding surface 66a. At this time, the molding dies 62a,
The time required from the end of opening 62b to picking up the pulp fiber molding 100, that is, the mold release time is, for example, 1 to
It takes about 3 seconds.

Here, in the present embodiment, the molding die 62 for after-pressing has a corner portion of the molding surface 66 and, for example, 3 to 30 (m) for injecting air from the molding surface 66.
It is configured to include a plurality of air injection holes 86 having one end opened in a recess (recess bottom surface 64a) having a predetermined small opening width of about m). Therefore, when the pulp fiber molded body 100 is released from the molding surface 66 of the molding die 62 after the completion of pressurization, air is ejected from the plurality of air ejection holes 86 to be brought into close contact with the molding surface 66. Pulp fiber molding 10
0 can be separated from the molding surface 66. Therefore, as compared with the conventional molding die that requires manual release of the pulp fiber molding 100 from the close contact state because the air injection hole 86 is not provided,
It is possible to obtain a molding die for after-pressing that can easily perform the releasing work. For example, the mold release time is about 1 to 3 seconds in this embodiment, whereas the conventional mold requires about 15 seconds.

Moreover, since the corners and the bottom surface 64a of the concave portion of the molding die 62 are relatively hard to be deformed in correspondence with the corners and the convex portions of the narrow width of the pulp fiber molding 100, as described above, the air is jetted. Almost no deformation occurs.

In the present embodiment, the bottom surface 64a of the recess, that is, the recess having a predetermined small opening width, has a width of, for example, 3
It has a dimension of about 30 (mm) and a depth of 10 (mm) or more. Therefore, the air injection hole 86 can be formed while maintaining the shape of the molding surface 66, and the pulp fiber molding 100 is not deformed during air injection.

In this embodiment, the air injection hole 8
6 has a size of, for example, φ 0.5 to 30 (mm), and is provided with a density of, for example, 1/9 to 1/20000 (pieces / mm ² ). Therefore, a sufficient amount of air is ejected to release the pulp fiber molded body 100, and the traces of the holes left after the pressurization are not conspicuous and the surface roughness is kept good.

Further, in this embodiment, the molding die 62 is used.
Is provided on the rear surface side (rear surface 78 side) of the molding surface 66, the other ends of the plurality of air injection holes 86 are opened, and the through holes 8 for supplying air to the plurality of air injection holes 86 are provided.
8 further includes a groove-shaped closed space 84 connected to 8. In this way, the closed space 84 is partitioned into a groove shape, so that the rigidity of the molding die 62 is enhanced as compared with the case where there is no partition.

Further, in this embodiment, the groove-shaped closed space 84 is entirely in a cross section (that is, in the plane of the back surface 78) passing through the closed space 84 perpendicular to the pressurizing direction of the pulp fiber molded body 100. It is formed to occupy about half of the area. In this way, the proportion of the groove-shaped closed space 84 in the cross section perpendicular to the pressurizing direction is made small, so that the back surface side of the molding die 62 is provided for heating the pulp fiber molding 100. Heater 7
Since the heat generated by 6 is efficiently conducted to the molding surface 66, the pulp fiber molded body 100 is easily heated.

Further, in this embodiment, the molding surface 6 is used.
6 is composed of a fluororesin layer 70. In this way, the molding surface 66 and the pulp fiber molding 100
Since the slipperiness of the molding surface 66 after the pressurization is completed,
The adhesiveness between the pulp fiber molded body 100 and the pulp fiber molded body 100 is lowered, and the mold release is further facilitated.

Further, in this embodiment, the after-press of the pulp fiber molding 100 has a residual water content of 10 to 15 (wt).
%), The pulp fiber molded body 100 is heated to a molding die 62 heated to a predetermined temperature at which the residual moisture can evaporate.
It is performed by applying pressure. Therefore, since the pulp fiber molded body 100 is heated at the same time as being pressed, the pulp fiber molded body 100 is pressed during the pressing.
Moisture contained therein is evaporated to form a water vapor layer between the molding surface 66 and the pulp fiber molded body 100. Therefore, the adhesiveness between the pulp fiber molding 100 and the molding surface 62 is further reduced, and the releasability is enhanced.

Further, in this embodiment, the above-mentioned predetermined temperature is 100 to 250 (° C.). By doing so, since the temperature is relatively high, the pulp fiber molded body 1
Most of the water in 00 is evaporated, and the shape retention of the pulp fiber molded body 100 after afterpressing is enhanced.

Further, in this embodiment, the base material 68 of the molding die 62 is made of cast aluminum alloy. Therefore, hot pressing, in which heating and pressing are performed, is preferably performed.

Next, another embodiment of the present invention will be described. In the following description, the description of the same parts as those in the above-described embodiment will be omitted.

FIG. 5 is a view showing another shape of the air injection hole 38 provided in the molding die 62. This air injection hole 38
On the surface 64 side (molding surface 66 side) has a diameter of 3 to 20 (m
m) while opening on the back surface 78 side, for example with a diameter of 2-18
It is formed in a stepped shape with an opening of about (mm). On the surface 64 side, the opening of the air injection hole 38 is formed by a large number of crosspieces as shown in the figure, and is constituted by a plurality of slit-shaped holes 40 arranged along one direction. Has become.

Therefore, the surface 6 of the air injection hole 38 described above is
The opening area on the 4 side becomes relatively large, and the pulp fiber molded body 100 is formed on the surface 64 side as in the above-described embodiment.
After pressure molding, a sufficiently large amount of air is jetted when the pressurized air is jetted for mold release. It should be noted that at the time of pressure molding, a trace of the air injection hole 38 is left on the surface of the pulp fiber molded body 100, but the trace corresponds to the plurality of slit-shaped holes 40 and a plurality of thin and low ridges. Therefore, it is hardly noticeable.

Although one embodiment of the present invention has been described in detail with reference to the drawings, the present invention can be implemented in still another mode.

For example, in the above-described embodiment, the forming die 62 was made of a light alloy such as an aluminum alloy, but it may be made of a zinc alloy, stainless steel, iron or the like, and when it is not heated. It may be made of resin such as epoxy resin.

Further, in the embodiment, a fluororesin layer 70 is formed on the surface 64 of the base material of the molding die 62 as a surface treatment for improving the slidability with the pulp fiber molding 100, and the molding surface 66 is formed. Although it is composed of the fluororesin layer 70, the surface treatment may be, in addition to forming the fluororesin layer 70, forming a plating layer or improving the surface roughness to, for example, about 100S. Further, the surface treatment does not necessarily have to be performed.

Further, in the embodiment, the water vapor layer is formed between the molding surface 66 and the molding surface 66 at the time of after-pressing by increasing the residual water content after the drying step of the pulp fiber molding 100, but, for example, In the drying process, the pulp fiber molded body 1 is dried as usual by a residual water content of about 6 to 8 (wt%) and sprayed before being subjected to afterpressing.
The same effect can be obtained by moistening 00. Further, the water vapor layer does not necessarily have to be formed, and the pulp fiber molded body 100 dried as usual may be subjected to after-pressing as it is.

Further, in the embodiment, the groove 80 in which the air injection hole 86 is opened is formed in the back surface 78 of the base material 68 of the molding die 62, so that the groove-like closed space 84 is formed between the groove 80 and the base 74. However, if the rigidity of the molding die 62 is sufficiently high, a rectangular closed space 84 that is not partitioned in a groove shape may be provided. However, when a heater 76 is provided on the back surface of the molding die 62 to heat at the same time as pressurization, the cross-sectional area of the portion in which the closed space 84 is formed is increased as much as possible in order to enhance heat transfer to the molding surface. Since it is desired to be large, it is desirable to form it in a groove shape so that the area occupied by the closed space 84 becomes 1/2 or less.

Further, in the embodiment, the molding dies 62a and 62b of the afterpress device 60 are provided with heaters 76 and 62, respectively.
Although the heater 76 is provided, the heater 76 does not necessarily have to be provided. That is, in the after-pressing step, the pulp fiber molded body 100 may be simply pressurized.

Further, in the embodiment, the compressor 9
Although the through-hole 88 that functions as an air supply port for sending the pressure air from 2 to the air injection hole 86 is provided in the base 74, it may be provided in the side surface of the base material 68.

Although not specifically exemplified, the present invention is
Various changes can be made without departing from the spirit of the invention.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a pulp fiber molded body manufacturing apparatus to which a molding die according to an embodiment of the present invention is applied.

FIG. 2 is an enlarged view showing a configuration of a molding die used in the afterpress device of the pulp fiber molded body manufacturing apparatus of FIG.

FIG. 3 is a diagram illustrating the shape of the back surface of the base material of the molding die of FIG.

FIG. 4 is a process diagram illustrating a method for manufacturing a pulp fiber molded body by the pulp fiber molded body manufacturing apparatus in FIG.

FIG. 5 is a view showing a molding die according to another embodiment of the present invention.

[Explanation of symbols]

62: Mold 66: Molding surface 86: Air injection hole 100: Pulp fiber molding

Front page continuation (72) Inventor Ichitoshi Shimojo 1-36 Noritake Shinmachi, Nishi-ku, Nagoya-shi, Aichi Prefecture Noritake Company Limited Limited (72) Inventor Masakatsu Kibuchi 3-chome, Noritake Shincho, Nishi-ku, Aichi Prefecture Aichi Prefecture No. 36 Noritake Company Limited (56) Reference JP 7-42100 (JP, A) JP 7-3700 (JP, A) JP 53-147802 (JP, A) JP 63-165600 (JP, A) JP-A 7-70997 (JP, A) JP-A 8-232199 (JP, A) JP-A 6-316900 (JP, A) JP-A 7-292599 (JP , A) JP-A-7-292598 (JP, A) JP-A-8-49200 (JP, A) JP-A-53-65406 (JP, A) JP-A-8-302597 (JP, A) (58) Fields surveyed (Int.Cl. ⁷ , DB name) D21J 1/00-7/00

Claims (4)

(57) [Claims] 1. In order to press-mold a pulp fiber molded body molded from pulp fibers in pulp slurry into a predetermined shape,
A molding die for afterpressing, comprising a molding surface formed in a shape corresponding to either the front surface or the back surface of the pulp fiber molded body of the predetermined shape, for injecting air from the molding surface, corners and predetermined small on at least one end of the opening recess width seen including a plurality of air injection holes are opened, the opening portion of the molding surface side of each of the air injection holes of several plurality of molding surfaces
Consists of a plurality of slit-shaped holes arranged in parallel along one direction.
After-press mold, characterized in that that. 2. A groove-shaped closure provided on the back surface of the molding surface.
A space, and the other ends of the plurality of air injection holes are the closed space.
To the plurality of air jets.
The afterpress molding die according to claim 1, wherein the molding die is connected to an air supply port for supplying air to the hole . 3. The groove-shaped closed space is formed so as to occupy an area of 1/2 or less of the total area in a cross section passing through the closed space perpendicular to the pressing direction of the pulp fiber molded body. The molding die for after-pressing according to claim 2, which is present. 4. The afterpress molding die according to claim 1, wherein the molding surface is subjected to a surface treatment for enhancing the slipperiness with the pulp fiber molding.