JPH09296399A - Production of pulp fiber molded product - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a pulp fiber molded product, capable of suppressing the strength decrease and breakage of the molded product on an after-press process. SOLUTION: A pulp fiber molded product 100 is adsorbed so as to give a shape wherein a standing surface 112 is extended only by a prescribed length dD in the demolding direction on the basis of a desired shape after dried. In an after-press process, the projected part 100c of the standing surface 112 is thereby brought into contact with the bottom surface 78 of the depressed part 76 of a mold 62a in a state that a bottom surface (back surface 100d) continued to the standing surface 112 is separated from the tip surface of the projected part 80 of the mold 62a only by a distance corresponding to the prescribed length dD in addition to the thickness of the pulp fiber molded product 100. Thereby, a tension generated on the standing surface 112 by pressing a pulp fiber aggregation formed in the projected part 100c of the pulp fiber molded product 100 with the projected part 84 of a mold 62b is reduced with a compression force (p) generated on the standing surface 112 by pressing the bottom part 100b.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a manufacturing method for manufacturing 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 with a package or cushioning material having a recess corresponding to the shape of the product or the like. As such a packaging and cushioning material, expanded polystyrene or the like is usually used. However, it has recently become a serious problem that these materials cause environmental pollution upon disposal.

[0003] On the other hand, pulp fiber molding called pulp mold is made from pulp (raw material for papermaking) obtained from waste paper such as corrugated cardboard or newsprint which can be easily disposed of for the purpose of effective use of collected resources. Manufacture of a body is performed, and such a pulp fiber molded body is used as a packaging material with low 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, when the pulp fiber molded body 120 is adsorbed to the papermaking mold 122 and its shape is relatively complicated, as shown in FIGS. 1 (a) to 1 (c),
A pool 126 of pulp fibers is likely to be formed on the back surface 124 side of the pulp fiber molded body 120. That is, as shown in (a), for example, the width w of the opening is about 15 (mm) or less and the opening area is small 128, the radius of curvature R is about 10 (mm) or less, or the height is small. In the case where h is about 30 (mm) or higher, the bottom portion 134 of the standing surface 132 and the like are likely to be entangled with each other, and the suction holes are provided with the same surface density as other portions. In addition, due to the fact that the suction amount per volume increases, the accumulation 126 of pulp fibers is likely to occur. Here, the “standing surface” means a surface having an angle θ of 45 ° or less with respect to the releasing direction which is the upper direction in the figure. Further, in the drawing, the suction hole of the papermaking mold 122 is omitted.

The portion where the pulp fiber pool 126 is formed is extremely thick with respect to the desired shape of the pulp fiber molding 120, but as shown in FIG.
A pair of molding dies 136a, 13 for applying after-press
6b has a shape of its molding surface 138 so as to be fitted to each other in a state where a gap corresponding to the thickness of the desired shape of the pulp fiber molded body 120 is formed. Therefore, when the pulp fiber molded body 120 is dried and after-pressed, the pair of molding dies 136a, 13a
Due to the fact that the tip portion of the convex portion 140 of the upper mold 136b of 6b compresses the above-mentioned pulp fiber pool 126,
A tensile force as shown by an arrow T is generated on the standing surface 142 located above the pulp fiber pool 126. As a result, there is a problem that the wall thickness of the standing surface 142 becomes thin or breaks, which lowers the strength and impairs the aesthetic appearance.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a method for producing a pulp fiber molded body which suppresses strength reduction and breakage during afterpressing. is there.

[0008]

In order to achieve such an object, the gist of the present invention is that a pulp having a predetermined shape having a standing surface that forms an angle of 45 ° or less with respect to the mold release direction from the pulp slurry. A method for producing a fiber molded body, which comprises (a)
At least a part of the standing surface is obtained by immersing the papermaking mold having a suction surface formed on the surface of the base material in which a large number of suction holes are opened, into the pulp slurry, and sucking the pulp slurry from the suction holes. Is an adsorption step of adsorbing the pulp fibers in the pulp slurry onto the adsorption surface so that the shape is extended by a predetermined length in the releasing direction with respect to the predetermined shape after drying, (b) A drying step of removing the pulp fiber molded body adsorbed on the adsorption surface from the adsorption surface and drying it, and (c) providing the dried pulp fiber molded body with a molding surface formed into the predetermined shape. And an after-pressing step of obtaining a pulp fiber molded body having a predetermined shape by applying pressure from both sides with a pair of molding dies.

[0009]

As described above, in this way, in the adsorption step,
Pulp fibers are adsorbed on the adsorption surface so that at least a part of the standing surface is extended by a predetermined length in the releasing direction with respect to the predetermined shape after drying, and in the drying step, the pulp fiber is adsorbed on the adsorption surface. The pulp fiber molded body is removed and dried, and in the after-pressing step, the pulp fiber molded body is pressed from both sides by a pair of molding dies having the molding surface of the predetermined shape, whereby the pulp fiber of the predetermined shape is obtained. A molded body is obtained. Therefore, in the afterpressing step, the bottom surface (the back surface corresponding to the convex portion of the papermaking mold) that continues from the standing surface formed by extending a predetermined length in the releasing direction.
Is separated from the top surface of the convex portion of one of the molds by a distance corresponding to the predetermined length of the pulp fiber molded body in addition to the top surface of the standing surface (corresponding to the concave portion of the papermaking mold). Surface) is brought into contact with the bottom surface of the concave portion of the one mold.

According to the above, the tensile force generated on the standing surface by pressing the convex portion of the other molding die against the pool of pulp fibers formed on the back surface side of the pulp fiber molding extends a predetermined length in the mold releasing direction. When the bottom surface following the standing surface formed by pressing is pressed, it is relieved by the compressive force generated on the standing surface. Therefore, it is suppressed that the tensile force reduces the thickness of the standing surface, lowers the strength, and breaks.

The above "adsorption surface" is formed by the surface of the reticulated body when the preform of the papermaking die is dense and has a reticulated body on the surface thereof. When is porous, it is formed by the surface of the base material itself.

Further, in order to make the suction shape extend a predetermined length in the releasing direction, for example, a portion of the surface of the base material or the surface of the mesh body corresponding to the above-mentioned standing surface is released from the die. By forming the suction surface by extending it by a predetermined length in the direction, the suction surface shape may be a shape in which a portion corresponding to the standing surface is extended by a predetermined length. In this way, when the pulp fiber molded body is placed on one of the pair of molding dies during afterpressing, the convex portion of the one molding die and the surface corresponding to the convex portion of the pulp fiber molded body A gap corresponding to the predetermined length is formed between and. Therefore, when the pair of molding dies are brought close to each other, the bottom portion of the extending surface formed by extension, that is, the convex portion is crushed, and the compressive force acts on the standing surface continuous to the convex portion. At the same time, the convex portion is formed in the predetermined shape by following the forming die.

Further, instead of making the shape of the suction surface extended by a predetermined length as described above, for example, the surface density of the suction holes is made higher than usual to increase the suction force. The adsorption thickness of the pulp fiber at the bottom of the extending standing surface (the top of the convex portion of the papermaking mold) may be increased by a predetermined length with respect to the predetermined shape. By doing so, the bottom portion of the standing surface thickened by the predetermined length is crushed during afterpressing and compressed to a predetermined thickness, so that a compression force is applied to the standing surface continuous to the bottom portion. Will work.

[0014]

Other Embodiments Here, preferably, the after-pressing step corresponds to the peripheral portion of the pulp fiber molded body in the pressing direction in order to suppress outward movement of the peripheral portion. The molding die having a movement suppressing surface formed toward the pulp fiber molding on the outside of its peripheral edge so as to form an acute angle in the opposite direction to the molding surface presses the pulp fiber molding. . With this configuration, the movement suppressing surface suppresses the outward spreading of the peripheral edge portion following the standing surface of the pulp fiber molded body due to the compressive force acting on the standing surface. Therefore, a pulp fiber molded body with higher accuracy can be obtained.

Also, preferably, the predetermined length is made thicker than the thickness of the pulp fiber pool formed on the back surface of the pulp fiber molded body. By doing this, before the pool of pulp fibers is pressed and the tensile force acts on the standing surface, the bottom portion that is continuous with the standing surface is pressed so that the compressive force acts on the standing surface. . Therefore, it is possible to more reliably prevent the thickness of the standing surface from becoming thin due to the tensile force and the strength from lowering or breaking.

As described above, the pool of pulp fibers has, for example, an opening width of 15 (mm) in the papermaking mold.
It is likely to be formed on the standing surface at the time of after-pressing because it is easily formed on a small depression with an opening area of about 10 mm or less, a concave corner with a radius of curvature of about 10 (mm) or less, and a standing surface with a height of about 30 (mm) or more. In order to appropriately relax the obtained tensile force, it is desirable to form these portions by extending them in the releasing direction.

The above-mentioned predetermined length is within the range of 2 to 10 (mm) and within 3 times the thickness of the pulp fiber molding, that is, within the range of 1 to 10 (mm) before drying. It is preferable that the size is within 3 times the thickness of the pulp fiber adsorbed on the adsorbing surface of the papermaking mold. Regardless of the variation in the adsorption thickness of the pulp fiber, in order to reliably suppress tearing due to tension during afterpressing, it is preferable that the length before drying is 1 (mm) or more. This is because the length before drying is preferably 10 (mm) or less in order to accurately position the pulp fiber molded body on the molding die. Further, even if a pulp fiber pool having a thickness three times or more the thickness of the pulp fiber molded body is formed, the pulp fiber molded body having a desired thickness cannot be obtained because the amount of pulp fiber in the pulp fiber pool is large. It is desirable that the predetermined length is 3 times or less. It should be noted that, in order to prevent the positional displacement during afterpressing more reliably, it is more preferable that the predetermined length is 5 (mm) or less, that is, the length before drying is 5 (mm) or less.

Further, preferably, the angle of the movement suppressing surface is 45 ° or less, more preferably 30 ° or less with respect to the releasing direction. In order to make the trim line clear by crushing burrs etc. on the movement restraint surface at the time of pressing, it is preferably 45 ° or less, and further to make the trim line more clear, it is 30 ° or less. This is because it is preferable.

Further, the height of the movement restraining surface is preferably about 5 to 50 (mm) from the tip of the peripheral edge portion of the pulp fiber molding, and more preferably about 20 to 50 (mm). . That is,
Compared with the case where the movement suppressing surface is not formed, the mating surfaces of the pair of molding dies are about 5 to 50 (mm), and more preferably 20 to
It is formed with a shift of about 50 (mm) toward the upper mold side. In order to reliably suppress the movement of the pulp fiber molded body to the outside of the peripheral portion,
At least a height of 5 (mm) or more is required, and considering the deformation of pulp fiber moldings and variations in adsorption thickness, etc.
This is because 10 (mm) or more is preferable. Further, in order to facilitate the rubbing at the time of pressing, it is preferably 50 (mm) or less.

[0020]

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

FIG. 3 is a diagram showing a main configuration of a pulp fiber molded body manufacturing apparatus to which a method for manufacturing a pulp fiber molded body 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 a dried machine 54. Afterpress device 6 for increasing the accuracy of the pulp fiber molding 100
It has 0 and.

Papermaking mold 10 provided in the molding machine 50.
As shown in an enlarged view of a main part in FIG. 4, a base material 14 made of, for example, an aluminum alloy having a surface 12 formed in a shape corresponding to the pulp fiber molded body 100 to be molded, and the base material surface 12 A net-like body 16 which is formed in a similar shape and is provided in a state of covering the same to form a suction surface,
The base material 1 so that both ends are opened to the front surface 12 and the back surface 17.
4 and a plurality of suction holes 18 penetrating therethrough.

The base material 14 is a so-called standing surface 20 having an angle θ of 45 ° or less with respect to the releasing direction (vertical direction in the drawing).
It is provided with. Bottom surface 2 continuous with this standing surface 20
1 is formed at a position recessed by a predetermined length d of, for example, about 5 (mm) from the virtual bottom surface 21i indicated by the broken line in the figure, that is, the bottom surface determined based on the drying shrinkage of the pulp fiber molded body 100. There is. Therefore, the standing surface 20 is formed to extend by a predetermined length d in the mold release direction, and the recess formed by the standing surface 20 is formed deep by the predetermined length d.

The mesh 16 fixed to the papermaking mold 10 so as to cover the surface 12 of the base material 14 is made of, for example, polyester or polypropylene having a basis weight of about 20 to 50 (g / m ² ). Non-woven fabric, tricot, # 20 ~ # 200
A metal mesh such as stainless steel or brass having a wire diameter of 0.10 to 0.32 [mm] or a synthetic fiber mesh such as nylon or tetron, which is preformed into a shape along the surface 12 by using a press or the like. As shown in FIG. 5, the peripheral edge portion is fixed by the mesh body pressing frame 27.

When the mesh body 16 is made of a non-woven fabric, for example, a non-woven fabric having a predetermined thickness is hot-pressed to obtain a desired shape. At this time, the basis weight is 50 (g / m ² ).
20 (g)
/ m ² ) in some cases, resulting in an incomplete mesh. Therefore, a predetermined basis weight is secured by using only that portion as a multilayer. At this time, the superimposed nonwoven fabrics are attached to each other and to the surface 12 by bonding at appropriate positions to each other with an adhesive or the like, and the nonwoven fabrics are fixed to the peripheral edge portion by the mesh holding frame 27 to prevent peeling. You. The purpose of forming the multilayer is to secure a predetermined basis weight. For example, in the case of a complicated shape, a thick nonwoven fabric having a basis weight of about 100 (g / m ² ) may be used. In FIG. 1 and the like, the mesh holding frame 27 is omitted.

When the mesh body 16 is composed of a metal wire or a mesh of synthetic fiber, a part of the mesh body is fixed to the suction hole 18 at an appropriate position by using a wire or the like, and The contour (trim line) of the pulp fiber molded body 100 fixed to the peripheral portion by the body pressing frame 27.
Is clearly defined, and at the same time, peeling of the mesh 16 is prevented. In addition, the net-like body 16 may be integrally molded and configured, or may be configured by being molded in each of a plurality of divided parts and assembling the respective parts.

The back surface 17 of the base material 14
The suction holes 18 from the surface to the surface 12 are 2.0 to 3.5 (m
m) with an opening diameter of about 5 to 30 (m
It is provided at a plurality of places so as to open to the surface 12 at intervals of about m). The suction hole 18 is formed in a stepped hole shape such that the opening diameter on the back surface 17 side is sufficiently larger than that on the front surface 12 side, for example, about 5 to 10 (mm). The clogging by the pulp fibers inside is prevented. In addition, as shown in FIG.
Is inclined with respect to the surface 12 at an inclination angle of about 30 °, that is, at an inclination angle of about 60 ° with respect to the normal line of the surface 12. The arrangement density and diameter of the openings of the suction holes 18 are experimentally obtained so that the pulp fiber molded body 100 formed on the mesh body 16 has a uniform thickness.

Incidentally, FIG. 4 is a diagram schematically showing a mounting state of the papermaking mold 10 in the molding machine 50. In the figure, a chamber 23 is fixed to the tip of a support arm 22, and a flange surface 23 a of the chamber 23 is fixed.
Further, a base 24 to which the papermaking mold 10 is attached by bolts 26 is fixed by bolts 25a and nuts 25b. The base material 14 of the papermaking mold 10 has a recess 28 having a thickness of, for example, about 2 cm and having a shape along the front surface 12 of the base material 14 on the back surface 17. The closed space 30 is formed, and the suction hole 1 is formed.
8 communicates with this recess 28.

The closed space 30 formed by the recess 28 and the chamber 23 is connected to the switching valve 34 through the vertical hole 32 of the support arm 22. The switching valve 34 is switched between a suction position connected to the suction pump 38 via the drain tank 36 and a jetting position connected to the compressor 40 in accordance with a command from a control device such as a sequence controller (not shown). . Therefore, according to the switching position, the suction pump 38 is used to close the closed space 30.
The inside is made a negative pressure and is sucked from the suction hole 18, or air is ejected from the suction hole 18 by the compressor 40. The water stored in the drain tank 36 is appropriately discharged by a discharge pump 42.

Returning to FIG. 3, the molding machine 50 to which the papermaking mold 10 configured as described above is attached is rotatably supported by a supporting device (not shown) so as to be rotatable about an axis perpendicular to the paper surface. A shaft 94 is provided, and a pair of support arms 22 (22a, 22b) are attached to the rotation shaft 94 at rotation angle positions different from each other by 180 °. The papermaking dies 10a, 10a are attached to the tips of the support arms 22a, 22b.
10b are attached respectively. A pulp slurry tank 98 storing a pulp slurry 96 is provided below the rotating shaft 94. The papermaking dies 10a and 10b attached to the tips of the support arms 22a and 22b respectively have pulp slurry 96 at the lower end position. It is immersed inside. That is, the papermaking dies 10a and 10b are
Are provided on opposite sides of the pulp slurry tank 98 by being rotated about the axis thereof.
Is located inside the pulp sludge 96 and is sucked from the suction holes 18 while being immersed in the pulp sludge 96, whereby the pulp is adsorbed on the mesh body 16 and is sucked and dehydrated outside the pulp sludge 96. As a result, the pulp fiber molded body 100 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 indicated by a broken line. A release mold 102 that is movable in the direction is provided. The releasing mold 102 has a receiving surface 58 having a shape substantially corresponding to the shape of the back surface 100d of the pulp fiber molded body 100 that is adsorbed on the adsorption surface of the papermaking die 10, but other configurations are not shown. Since it is substantially the same as the papermaking mold 10 shown in FIG. 4, detailed description will be omitted. When the mold release tool 102 is located at the left end portion shown by the solid line, the mold release machine 52 is located at the lower end position lower than the position shown in the drawing, on the adsorption surface, that is, the pulp fiber molded body 100 on the mesh body 16. Of the pulp fiber molded body 100 on the carry-in conveyor 56 provided in the dryer 54 at the lower end position of the right end portion indicated by the broken line.
By lowering, the pulp fiber molded body 100 is conveyed from the molding machine 50 to the dryer 54.

The dryer 54 is provided in a box-shaped container 104 which is 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 and 62b, and heaters 64 and 64 are provided on the surfaces located on the opposite sides thereof. Molding die 62a,
Reference numeral 62b is made of, for example, an aluminum alloy, and molding surfaces 66a and 66b corresponding to the front surface 100a shape and the back surface 100d shape of the pulp fiber molded body 100 are formed at positions facing each other. . As shown in detail in FIG. 5, this molding surface 6
6a and 66b are mating surfaces 68a provided on the peripheral edge,
In a state where the 68b are in contact with each other (that is, in a state where they are closer to each other than the positions shown in the figure), a gap corresponding to the thickness of the pulp fiber molded body 100 after drying is generated between them. Is formed.

The pulp fiber molding 10 is provided on the peripheral portion of the lower mold 62a, which is one of the pair of molding dies 62a and 62b.
At a position outside the standing surface 70 corresponding to the standing surface 112 formed on the peripheral portion of 0, an acute angle of, for example, about 15 ° is formed in the direction opposite to the standing surface 70 with respect to the pressing direction indicated by the arrow P in the figure. An outer peripheral inclined surface 72 is formed so as to form an angle ψ. That is, the outer peripheral inclined surface 72 is formed so as to form a substantially V shape with the standing surface 70 and face the upper die 62b. The mating surfaces 68a and 68b are formed continuously from the end of the outer peripheral inclined surface 72. Therefore, the height H is closer to the upper die 62b side than when the outer peripheral inclined surface 72 is not formed. It is located in a displaced position. In addition,
A mating surface 68 is provided at a slightly inner position on the peripheral edge of the upper mold 62b.
The outer peripheral inclined surface 72 in the state where a and 68b are brought into contact with each other.
A protruding portion 74 for forming a gap corresponding to the thickness of the pulp fiber molded body 100 is formed between the raised surface 70 and the standing surface 70.

A method for manufacturing the pulp fiber molded body 100 using the pulp fiber molded body manufacturing apparatus configured as described above will be described with reference to FIG. 3 and FIG. 6 showing the molding process for one papermaking mold 10a. explain. First, by operating a starter (not shown), the suction pump 38 and the compressor 40 of the molding machine 50, the suction pump (not shown) of the mold release machine 52, the heat source of the dryer 54, etc. are started. In addition,
The suction pump 38, the compressor 40, and the like may be started and stopped in accordance with the switching operation of the switching valve 34 and the like in each step described later.

After the above-mentioned start-up operation, the rotary shaft 94 is rotated in the dipping step of step 1, whereby the papermaking mold 10a located on the upper side is rotated downward as shown by the arrow A in FIG. The papermaking mold 10b located on the side is rotated upward. Next, in the suction step of step 2, during the rotation, the switching valve 34 connected to the papermaking mold 10a is switched to the suction position while operating the suction pump 38, so that the suction hole 18 of the papermaking mold 10a is changed.
Start suction from.

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 sludge 96 is held for a predetermined predetermined adsorption time. The pulp fibers therein are adsorbed on the mesh 16. At this time, as shown in FIG. 4, the bottom surface 21 of the surface 12 of the base material 14 is provided at a position recessed by a predetermined length d from the virtual bottom surface 21i in which only the amount of drying shrinkage is taken into consideration. The pulp fiber is adsorbed in a shape in which the length in the vertical direction (that is, the releasing direction) of FIG. 4 is extended by a predetermined length d of, for example, about 5 (mm), following the shape thereof.

The above predetermined adsorption time is set to a relatively short time of, for example, about 2 seconds, and the adsorption time of the pulp fiber molding 100 is taken into consideration in consideration of the compression amount at the time of after-pressing described later. The adsorption thickness is set to be about 1 to 10 times, preferably about 2 to 5 times, more preferably about 2 to 3 times the desired product thickness after the after-pressing. When the above predetermined time has elapsed, in the pulling up step of step 4,
While the suction from the suction hole 18 is continued, the papermaking mold 10a is taken out of the pulp slurry 96, and in the dehydration step of step 5, suction is continued on the mesh body 16 by continuing suction for a predetermined time of, for example, about 10 seconds. The pulp fiber thus formed is dehydrated to form the pulp fiber molded body 100. Since the suction from the suction holes 18 is continuously performed, the dehydration step is executed immediately after the papermaking mold 10a is taken out of the pulp slurry 96 in the pulling up step.

After the dehydration is completed as described above, in the releasing step of step 6, the releasing die 102 is lowered so as to be located at the left end position thereof, and the papermaking die 10a is inserted through the pulp fiber molding 100. , The switching valve 34 on the side of the papermaking mold 10a is switched to the ejection position to eject the air from the suction hole 18, and at the same time, the air is sucked from the suction hole (not shown) of the receiving surface 58 of the release mold 102. Then, the pulp fiber molded body 100 is adsorbed to the receiving surface 58 by raising the mold release mold 102 while continuing the ejection from the suction hole 18 and the suction of the mold release mold 102. It is released from the papermaking mold 10a.

Subsequently, after the mold 102 for releasing the pulp fiber molded body 100 adsorbed thereon is raised to the 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
After descending to the lower end position shown in the figure, air is ejected from the suction hole to form the pulp fiber molded body 10
0 is peeled off from the receiving surface 58 and dropped onto the carry-in conveyor 56 of the dryer 54.

Then, in the drying step of step 7, the pulp fiber molding 100 dropped on the carry-in conveyor 56 is sequentially fed into the box-shaped container 104 of the dryer 54 and transferred onto the table 106, The box-shaped container 104 is rotated clockwise in FIG. 3 while being mounted 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. 5, and the right lower end position in the box-shaped container 104. At, the transfer conveyor 110 is moved.

In the after-pressing step of the following step 8, the pulp fiber molded body 100 conveyed by the carry-out conveyor 110 is used to form the molding surface 66a of the molding die 62a (lower die).
, The heaters 64, 64 are actuated and the molding die 62b (upper die) is lowered, so that the pulp fiber molding 100 is moved from the heater 64 to the pair of molding dies 62a, 62b. At the same time, it is heated by the conduction heat of and is pressure-molded. As a result, the molding surface 66
A pulp fiber molded body 100 molded into a desired shape and thickness according to the shape of the gap formed between a and 66b.
Is obtained.

At this time, as described above, since the bottom surface 21 of the base material 14 of the papermaking mold 10 is provided at a position recessed from the shape taking dry shrinkage into consideration, the pulp fiber molded body 100 after dry shrinkage is formed. The height in the pressing direction is higher than the original height by a predetermined length d _D of, for example, about 1 to 10 (mm). Therefore, in the recess 76 of the molding die 62a, the bottom portion 100c of the pulp fiber molding 100 is the bottom surface 78.
On the other hand, in the convex portion 80 of the molding die 62a, a gap 82 having a height d _D (= 1 to 10 [mm]) is formed between the surface 100a of the pulp fiber molding 100 and the molding surface 66a. It is formed. That is, in the adsorption step described above, the standing surface 20 of the pulp fiber molded body 100 on the molding surface is shown in FIG. 5 in the releasing direction with respect to the desired shape of the pulp fiber molded body 100 after drying. It is adsorbed so as to have a deformed shape extended by a predetermined length d _D (= d × dry shrinkage ratio = 1 to 10 [mm]).

Therefore, when the molding die 62b is lowered after the pulp fiber molding 100 is placed on the molding die 62a, the surface 100a of the convex portion 80 is changed to the molding die 62.
The bottom portion 100b continuous with the standing surface 112 is pressed by the molding surface 66b of the molding die 62b so as to come into contact with the molding surface 66a of a. As a result, the molding surface 66a
The compressive force p acts on the standing surface 112 between the molding surface 66b and the molding surface 66b.

By the way, when the pulp fiber molded body 100 is molded by adsorbing the pulp fibers on the adsorption surface of the papermaking mold 10, the papermaking mold is caused by the entanglement of pulp fibers and the nonuniformity of suction force. An accumulation of pulp fibers occurs in the convex portion 100c of the pulp fiber molded body 100 (that is, the bottom portion viewed from the back surface 100d side of the pulp fiber molded body 100) corresponding to the concave portion of 10. Since the convex portion 100c in which the pulp fiber is accumulated is thicker than the other portions, the molding dies 62a, 62 in the afterpressing step.
When the pressure is applied between b, the convex portion 100c becomes
A tensile force acts on the standing surface 112 due to being compressed by the convex portion 84 of b. However, in this embodiment, since the compression force p based on the pressing of the bottom portion 100b is applied to the standing surface 112 as described above, the thickness of the standing surface 112 is thin due to the action of the tensile force. It is possible to suppress the occurrence and the breakage.

In this embodiment, as is apparent from FIG. 5, in the initial stage when the bottom 100b is pressed, the pulp fiber pool formed in the projection 100c is not pressed by the projection 84. . Therefore, the tensile force resulting from the compression of the pulp fiber pool substantially does not act on the standing surface 112 at all, so that the above-mentioned problems caused by the tensile force are more reliably suppressed. That is, in this embodiment, the predetermined length d
Is set so that the predetermined length d _D after drying is larger than the amount of increase in thickness due to the formation of pulp fiber pools in the convex portions 100c.

Outside the standing surface 70 corresponding to the standing surface 112 formed on the peripheral portion of the pulp fiber molded body 100, an outer peripheral inclined surface 72 having a substantially V shape with the standing surface 70 is provided. Therefore, due to the compressive force acting on the standing surface 112 as described above, the pulp fiber molded body 10
The outer peripheral inclined surface 72 is that the peripheral edge portion of 0 spreads outward.
Is suppressed by

In summary, in this embodiment, when the pulp fiber molded body 100 having a predetermined shape is obtained, in the adsorption step of step 3, the standing surface 112 is dried by a predetermined length in the releasing direction with respect to the predetermined shape after drying. pulp fibers suction surface such that the d _D only extended shape (mesh body 16
In the drying step of step 7, the pulp fiber molding 100 on the adsorption surface is dried after being removed from the papermaking mold 10, and the pulp fiber molding 100 is heated in the afterpress step of step 8. At the same time, the pulp fiber molded body 100 having the predetermined shape is obtained by being pressed from both sides by the pair of molding dies 62a and 62b having the molding surfaces 66a and 66b having the predetermined shape.

Therefore, in the afterpressing process,
The bottom surface (the back surface 100d of the bottom portion 100b corresponding to the convex portion of the papermaking mold 10) following the standing surface 112 formed by extending the mold release direction by a predetermined length d _D has the convex portion 80 of the one molding die 62a. In addition to the thickness of the pulp fiber molded body 100 from the top surface (the molding surface 66a on the convex portion 80), the standing surface 112 thereof is separated by a distance corresponding to the predetermined length d _D thereof.
Convex part (surface 100a corresponding to the concave part of the papermaking mold 10) 1
00c is the bottom surface 78 of the concave portion 76 of the one molding die 62a.
To abut.

As described above, when the convex portion 84 of the other molding die 62b presses the pool of pulp fibers formed on the back surface 100d side of the convex portion 100c of the pulp fiber molded body 100, the tensile force generated on the standing surface 112 is increased. , The bottom surface (the back surface 100d of the bottom portion 100b) following the standing surface 112 formed by extending the predetermined length d _D in the releasing direction is pressed, and is relaxed by the compressive force p generated on the standing surface 112. Therefore, it is suppressed that the tensile force reduces the thickness of the standing surface 112, which lowers the strength and causes breakage.

Further, in this embodiment, the after-pressing step of step 8 corresponds to the peripheral portion of the pulp fiber molded body 100 in the pressing direction in order to suppress outward movement of the peripheral portion. In the direction opposite to the standing surface 70 of the molding surface 66a
By the forming dies 62a and 62b having the outer peripheral inclined surface 72 that functions as a movement restraining surface formed toward the pulp fiber molded body 100 outside the peripheral edge thereof so as to form a predetermined angle ψ of an acute angle of about 15 °. , Its pulp fiber molding 1
00 is pressurized. In this way, the outer peripheral inclined surface 72 prevents the peripheral edge portion following the standing surface 112 from spreading outward due to the compressive force p acting on the standing surface 112 of the pulp fiber molded body 100. Therefore, the pulp fiber molded body 100 with higher accuracy can be obtained.

Further, in the present embodiment, the predetermined length d _D is such that the pulp fiber molding 100 is formed in the convex portion 100c.
It is made thicker than the thickness of the pool of pulp fibers formed on the back surface 100d (that is, the amount of increase in thickness due to the formation of the pool). By doing so, before the pool of pulp fibers is pressed and the tensile force acts on the standing surface 112, the bottom portion 100b continuous to the standing surface 112 is pressed, so that the compressive force p is applied to the standing surface 112. Will work. Therefore, it is possible to more reliably prevent the thickness of the standing surface 112 from being thinned due to the tensile force, resulting in a decrease in strength and breakage.

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

For example, in the above-mentioned embodiment, the papermaking mold 10 and the molding mold 62 were made of a light alloy such as an aluminum alloy. However, general steel, tool steel, metal such as brass, resin such as epoxy resin, etc. It may be manufactured. If the papermaking mold 10 has a porous structure that is made porous by binding inorganic particles such as resin spheres, glass spheres, and ceramic spheres with an adhesive, a suction hole is not necessary. Becomes

Further, in the papermaking mold 10, the suction hole 18
Was formed in a stepped hole whose opening diameter on the back surface 17 side was larger than the opening diameter on the front surface 12 side. However, for example, it was formed in a conical shape whose cross-sectional area gradually increased from the front surface 12 side to the back surface 17 side. May be. If clogging is unlikely to occur, the entire structure may have the same cross-sectional area.

Further, in the above-mentioned embodiment, the suction hole 18 is inclined with respect to the normal line of the surface 12, but it may be formed in parallel with the normal line, that is, in the direction perpendicular to the surface 12.

Further, in the embodiment, all the bottom surfaces 21 continuous with the standing surface 20 in the papermaking mold 10 are formed to be recessed from the virtual bottom surface 21i in consideration of drying shrinkage.
It is not always necessary to form all the recesses, and the effect of the present invention can be obtained if the portion where the pulp fiber pool is formed is recessed.

When the bottom surface 21 is formed so as to be recessed from the virtual bottom surface 21i, the predetermined distance d is not necessarily the papermaking mold 10.
Need not be uniform on the surface 12. That is, for example, the thickness of the pulp fiber pool that can be formed in each part is experimentally obtained in advance, and the tensile force T shown in FIG. 2 is sufficiently relaxed according to the thickness of the pool. The predetermined distance d may be determined.

Further, in the embodiment, the molding dies 62a and 62b of the afterpress device 60 are provided with heaters 64,
Although the heater 64 is provided, the heater 64 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, since the molding die 62a is provided with the outer peripheral inclined surface 72, the outward expansion of the pulp fiber molded body 100 at the time of pressurization is suppressed, but the size of the gap 82 is large. If the (predetermined distance d _D ) is relatively small and it is difficult for the outward spread to occur, the outer peripheral inclined surface 72 does not necessarily have to be provided.

Further, in the embodiment, the bottom surface 21 of the papermaking mold 10 is formed so as to be recessed downward by a predetermined distance d from the virtual bottom surface 21i in consideration of drying shrinkage.
0 was extended, but on the contrary, the tip end surface of the convex portion of the papermaking mold 10 which is convex upward in FIG.
The standing surface 20 may be extended by forming only the height. That is, the effect of the present invention can be obtained if the standing surface 20 is extended in at least one of the upper and lower sides of the mold releasing direction (vertical direction in the drawing).

Further, in the embodiment, the suction surface is extended by changing the shape of the base material surface 12 of the papermaking mold 10 and providing the standing surface 20, but for example, the papermaking mold 10 is The pulp fiber molded body 100 is formed into a shape (shape shown by a broken line in FIG. 4) in consideration of drying shrinkage, and the net body 16 provided on the surface 12 is formed thick on the tip end surface of the convex portion, thereby standing. The suction surface of the papermaking mold 10 corresponding to the surface 112 may be extended.

In the embodiment, the gap 82 is formed between the dried pulp fiber molding 100 and the molding die 62a as shown in FIG. In FIG. 4, in the papermaking mold 10 having a virtual bottom surface 21i instead of the bottom surface 21, the papermaking mold 10
The pulp fiber molded body 100 in which the gap 82 in FIG. 5 is solid may be molded by increasing the suction force on the tip end surface of the convex portion. Even with this,
Since the solidified portion is crushed to a predetermined thickness, the compressive force p is generated as in the embodiment,
Similar effects can be obtained.

In addition, although not illustrated one by one, the present invention is
Various changes can be made without departing from the spirit of the invention.

[Brief description of drawings]

1 (a) to 1 (c) are views for explaining a mode of pulp fiber accumulation that occurs when pulp fibers are adsorbed to a papermaking mold.

FIG. 2 is a diagram illustrating a problem when the after-pressing is performed on the pulp fiber molded body in which the pulp fiber pool is formed as shown in FIG.

FIG. 3 is a diagram showing a configuration of a pulp fiber molded body manufacturing apparatus to which the manufacturing method of one embodiment of the present invention is applied.

FIG. 4 is an enlarged view showing an attached state of a papermaking mold used in the molding machine of the pulp fiber molded body manufacturing apparatus of FIG.

5 is a diagram illustrating a forming die of an afterpress device of the pulp fiber molded body manufacturing apparatus of FIG.

FIG. 6 is a process diagram illustrating a method for manufacturing a pulp fiber molded body using the pulp fiber molded body manufacturing apparatus in FIG.

[Explanation of symbols]

 62: Mold 66: Molding surface 70: Standing surface 82: Gap 100: Pulp fiber molding

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kazutoshi Shimojo No. 1-36 Noritake Shinmachi, Nishi-ku, Nagoya, Aichi Prefecture Noritake Company Limited Limited (72) Inventor Masakatsu Kibuchi Sanori Noritake, Nishi-ku, Nagoya, Aichi Prefecture No. 1-36 Noritake Company Limited Limited

Claims (2)

[Claims] 1. A method for producing a pulp fiber molding having a predetermined shape, which has a standing surface forming an angle of 45 ° or less with respect to the mold release direction from the pulp slurry, the surface of a base material having a large number of suction holes opened. By dipping a papermaking mold having a suction surface formed above in the pulp slurry and sucking the pulp slurry through the suction hole, at least a part of the standing surface is separated from the predetermined shape after drying. An adsorption step of adsorbing the pulp fibers in the pulp slurry onto the adsorption surface so that the pulp fiber has a shape elongated by a predetermined length in the mold direction; A drying step of removing from the adsorption surface and drying, and a step of pressing the dried pulp fiber molded body from both sides with a pair of molding dies having a molding surface formed in the predetermined shape. Pulp fiber Method for producing a pulp fiber molding, characterized in that the after-pressing to obtain a form, comprising. 2. The afterpressing step comprises forming an acute angle in a direction opposite to a molding surface corresponding to the peripheral portion with respect to the pressing direction in order to suppress outward movement of the peripheral portion of the pulp fiber molded body. 2. The pulp fiber molded body is pressed by a molding die having a movement suppressing surface formed toward the pulp fiber molded body on the outer side of the peripheral edge portion so as to be formed.
Of the pulp fiber molding of the above.