JP3253213B2 - Pulp mold manufacturing method and apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for manufacturing a pulp mold, and more particularly to an improvement in a dewatering method after pulp adsorption.

[0002]

2. Description of the Related Art When a predetermined product or the like is transported, the product or the like is packed in a state of being fitted with a packing material having a recess corresponding to the shape of the product or the like. Such a packing material is usually made of a relatively expensive material such as expanded polystyrene, which increases the cost and makes the disposal process difficult.

[0003] On the other hand, packing materials are manufactured from waste paper pulp such as corrugated cardboard or newsprint for the purpose of effective use of collected resources, and such packing materials are called pulp molds. I have. Such a pulp mold usually uses a molding die having a molding surface of a corresponding shape and formed with a large number of suction holes opened in the molding surface, and the molding surface of the molding die is put into pulp slurry. It is formed by sucking the pulp from the suction hole in the immersed state and adsorbing the pulp to the molding surface, and after the adsorbed pulp is dehydrated to a water content enough to maintain the shape, the pulp is removed from the mold. It is manufactured by releasing the mold and drying it with hot air in a drying furnace.

[0004]

By the way, the dehydration of the pulp is conventionally carried out by using a suction means such as a vacuum pump for adsorbing the pulp in the pulp slurry on the molding surface, and pulling up a molding die from the pulp slurry. Even after that, the suction was continuously performed by sucking from the inside of the mold. The dehydration by suction absorbs moisture contained in the pulp layer adsorbed on the molding surface together with air. However,
Since the pulp layer that is adsorbed has low airtightness, for example, when the vacuum pump has a reduced pressure of about 600 mmHg, the reduced pressure of about 100 to 150 mmHg is the limit inside the mold, and the pressure with the atmosphere is low. There is a problem that it takes a relatively long time to release the mold by dehydration to such an extent that the pressure difference is small and the shape of the pulp mold can be maintained, and the molding efficiency of the apparatus cannot be sufficiently obtained. Further, when a part of the pulp layer comes off by suction, the pressure inside the mold does not decrease sufficiently, and dehydration within a predetermined time becomes insufficient. Non-defective products were sometimes generated.

The present invention has been made in view of the above circumstances, and an object of the present invention is to reduce the time required for dewatering a pulp mold and improve the molding efficiency. Another object of the present invention is to prevent the occurrence of defective products due to insufficient dehydration.

[0006]

In order to achieve the above object, the gist of the first invention is to immerse a mold in which a number of suction holes are opened in a molding surface in pulp slurry and A method of manufacturing a pulp mold from the pulp slurry, including an adsorption step of adsorbing pulp in the pulp slurry on the molding surface by suction from the suction hole, and a dehydration step of dehydrating the adsorbed pulp. The dehydration step includes: (a) a cover step of air-tightly covering the pulp adsorbed on the adsorption surface of the molding die with a non-permeable membrane, and (b) pulp adsorbed on the molding surface of the molding die. By sucking from the suction hole while being covered by the non-permeable membrane,
The non-vented film is formed on the basis of the pressure difference between the atmospheric pressure and the negative pressure.
In close contact with the flop, and a suction step of nipping the pulp between its air-impermeable film and the mold is to contain.

[0007]

In this way, when dewatering the pulp adsorbed on the molding surface, the pulp is sucked from the inside of the molding die in a state where the pulp is air-tightly covered with the air -impermeable membrane. Therefore, the impermeable membrane is brought into close contact with the pulp surface based on the pressure difference between the pressure inside the mold and the atmospheric pressure on the surface of the impermeable membrane by suction. After the non-permeable membrane is adhered in this way, since the non-breathable membrane has a squeezing effect by being suctioned toward the molding surface based on the differential pressure, it is higher than when simply suctioning. Dehydration ability is obtained. Therefore, the dewatering time of the pulp mold on the mold is reduced and the molding efficiency is improved.
In addition, since the local removal of the pulp mold due to the suction of the mold is eliminated, the occurrence of defective products due to insufficient dehydration within a predetermined time is prevented.

[0008]

A second aspect of the present invention to achieve the above object is an apparatus for producing a pulp mold from pulp slurry,
(a) A mold having a large number of suction holes opened in a molding surface, and the mold is immersed in pulp slurry and sucked from the suction holes to adsorb pulp in the pulp slurry to the molding surface. A molding device to be provided, (b) a cover device having an impermeable membrane, and a cover device for airtightly covering the pulp adsorbed on the molding surface of the molding die with the impermeable membrane, and (c) a molding surface of the molding die. By sucking the pulp adsorbed to the air through the suction hole in a state where the pulp is covered by the non-permeable membrane ,
The non-vented film is adhered to the pulp based on the pressure difference from the negative pressure
Is allowed, and sandwiches and presses the suction means between the pulp and the air-impermeable film and the mold is to contain.

[0009]

In this manner, the pulp adsorbed on the molding surface by the molding device is sucked from the suction hole by the suction means in a state where the pulp is air-tightly covered by the air -impermeable membrane of the cover device. Is done. Therefore, the pulp adsorbed on the molding surface of the mold is sucked and dehydrated by the same operation as the first invention, and at the same time, the pulp layer is compressed by the air-impermeable membrane adsorbed on the molding surface. Is further dewatered, so that the dewatering time of the pulp mold on the mold is reduced and the molding efficiency is improved. In addition, since the local removal of the pulp mold due to the suction of the mold is eliminated, the occurrence of defective products due to insufficient dehydration within a predetermined time is prevented.

Preferably, the cover device comprises: (a) a suction surface having a shape substantially corresponding to the molding surface and having a predetermined number of suction holes formed therein, and a through hole communicating with the suction holes; (B) when the suction period within the mold is completed by the suction means, the pulp mold on the mold is set to a negative pressure when the suction means is closed by the suction means. And negative pressure means for releasing the mold by adsorbing. In this way, when the dehydration of the pulp mold is completed, the suction from the inside of the mold is stopped, and the pulp mold is sucked to the suction surface by sucking the suction from the suction hole opened in the suction surface of the housing. Release. At this time, a through hole is provided in the non-permeable membrane, but since the suction surface has a shape substantially corresponding to the molding surface, when the non-permeable membrane is covered with the pulp mold, the suction surface is formed on the molding surface. By making the close contact, the portion other than the vicinity of the through hole is adsorbed to the pulp mold surface, and is brought into close contact with the whole to obtain a squeezing effect. On the other hand, since the through hole is communicated with the suction hole opened on the suction surface, when the dewatered pulp mold is sucked on the suction surface, it is impermeable by sucking through the through hole. Adsorbed through the membrane. Therefore, the molding efficiency is further improved, and it is not necessary to separately provide the cover device and the release device.

[0011]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram illustrating an example of a pulp mold manufacturing apparatus to which the pulp mold manufacturing method of the present invention is applied. This pulp mold manufacturing apparatus includes a forming apparatus 10, a release apparatus 12, and a drying apparatus (not shown).

In the pulp mold forming apparatus 10, for example, a pulp slurry 14 in a slurry state in which pulp is dispersed in water at a concentration of about 1% by weight is stored in a liquid tank 16, and in the pulp slurry 14, A pair of molding dies 18a and 18b having the same configuration are alternately immersed. That is, the molds 18a and 18b are
20b are integrally attached to the upper surface, respectively.
Support arms 22a and 22b are integrally provided on the surfaces of the bases 20a and 20b opposite to the molds 18a and 18b.

A rotary shaft 24 is rotatably supported above the liquid tank 16 by a supporting device (not shown) with its axis positioned at right angles to the plane of FIG.
a and 18b are fixed to the rotating shaft 24, respectively, so that the molds 18a and 18b are fixed.
Are supported by the rotating shaft 24 in a state of being shifted from each other by 180 degrees. The molding dies 18a and 18b are alternately positioned at an upper position and a lower position by being rotated by 180 degrees by a driving device (not shown). In FIG. 1, the molding dies are positioned at a lower position. The mold 18b is immersed in the pulp slurry 14 in the liquid tank 16.

As shown in FIG. 2, the molding dies 18a and 18b each have a recess 26 on the surface on the base 20 side, and a space between the molding surface 28 and the recess 26 is formed. It has a number of suction holes 30 to communicate with each other. The suction holes 30 are formed by drilling at a rate of one per 1 cm ² , for example. The recesses 26 of the molds 18a and 18b are
0, the holes 34 of the support arms 22a and 22b, a passage (not shown) provided in the rotary shaft 24, and pipes 36a, which are rotatably communicated with the passage in the rotary shaft 24.
36b, the suction device 40 via the switching valves 38a and 38b.
And the compressor 42. The suction holes 3 are formed on the molding surfaces 28 of the molding dies 18a and 18b.
In order to prevent clogging of the pulp at 0, a mesh member 43 such as a wire mesh is integrally provided so as to cover the molding surface 28, and the pulp is adsorbed to the molding surface 28 via the mesh member 43. Is done.

On the other hand, the release device 12 has a suction surface 44 having a shape substantially corresponding to the molding surface 28 of the molding die 18, and a housing 46 formed of, for example, FRP and fixed to a base 45. A rubber film 48 having a thickness of, for example, about 5 mm is fixed to the suction surface 44 so as to cover the suction surface 44 from below, and an upper end is fixed to a side surface of the housing 46 so as to surround the suction surface 44. And a hanging film 50 extending downward, and attached to a carrier device (not shown) on a support shaft 52 so as to be movable in the vertical direction in the figure. The pulp mold 54 released from the mold 18 is dried. Convey to the device. Absorption surface 44 and membrane 4
8 has a predetermined number (sufficiently smaller than the number of suction holes 30) of suction holes 56 and through holes 58 that communicate with each other in a state where the film 48 is substantially in contact with the suction surface 44. For example, a hole 62 provided in the support shaft 52 and an on-off valve 64
A suction device 68 is connected via a passage 66 provided with a suction device. The on-off valve 64 functions as an atmospheric pressure introducing means for introducing the atmospheric pressure into the recess 60 through the passage 66. In the present embodiment, the rubber film 48 corresponds to a non-permeable film, and the release device 12 also functions as a cover device.

The operation of the pulp mold manufacturing apparatus configured as described above will be described with reference to the time chart of FIG. 3 for the pulp mold 54 formed by the forming die 18a. At time t ₀ , the rotating shaft 24 of the molding apparatus 10 is rotated by 180 degrees from the state of FIG. 1, and the molding die 1 which is one of the pair of molding dies 18a and 18b is formed.
The switching valve 38a is switched to the suction device 40 side in a state where the suction device 8a is located on the lower side and is immersed in the pulp slurry 14 of the liquid tank 16, and the suction device 40 sucks the switching valve 38a. By making the recess 26 have a negative pressure for a predetermined time (that is, between times t _{0 and} t ₁ corresponding to the adsorption step), the pulp in the pulp slurry 14 is sucked from the suction holes 30 and is placed on the molding surface 28. Adsorbed. Therefore, a pulp mold 54 having a shape corresponding to the uneven shape of the molding surface 18 and a thickness of, for example, about 2 mm is formed on the molding die 18a. Then, at time t ₁ ~t _3, the mold while continuing the suction of the molding die 18a 18
a, 18b are rotated 180 degrees to position the other mold 18b at the lower position (ie, in the state shown in FIG. 1),
By sucking through the suction hole 30 of the mold 18b in the same manner as described above, the pulp mold 54 is also placed on the mold 18b.
Is started. During this time, at time t _2, the switch valve 64 is opened and the recess 60 is the atmospheric pressure.

On the other hand, when the rotation is completed at time t ₃ , the housing 46 is approached from above to the mold 18 a located at the upper position, and the film is transferred to the pulp mold 54 on the molding surface 28 at time t ₄ . 48 is overlaid. At this time, as described above, the membrane 48 has only a peripheral portion fixed to the suction surface 44, and is separated from the suction surface 44 by a small distance (for example, about 5 mm) inside in the non-approaching state. In addition, even when the film 48 is covered with the pulp mold 54, the suction surface 44 and the film 48 are slightly separated from each other. Further, as a result of the housing 46 being brought close to the molding die 18a, the lower portion of the dripping film 50 covers the side surface of the molding die 18a. In the present embodiment, the time t ₃ ~t ₄ corresponds to covering step.

As described above, when the housing 46 is
The suction by the suction device 40 is continued before and after being approached. When the membrane 48 is covered with the pulp mold 54, the inside of the membrane 48 (that is, the recess Since the pressure 60) is set to the atmospheric pressure, the film 48 is sucked toward the molding die 18a and deformed based on the pressure difference, and is brought into close contact with the pulp mold 54.
At this time, the hanging film 50 covering the side surface of the molding die 18a is formed.
The outside is also at atmospheric pressure, and the recess 26 is under negative pressure, that is, the space between the molding surface 28a and the membrane 48 is under negative pressure. It is brought into close contact with the side surface of the pulp mold 54 that has been adsorbed. FIG. 2 shows the membrane 48 and the sagging membrane 50 in this manner.
Shows the state after is adsorbed. In addition,
In the present embodiment, the suction device 40 and the switching valve 38 correspond to suction means.

[0019] Then, to continue the aspiration In yet time t ₄ ~t _5, after the water content of the pulp mold 54 has been lowered sufficiently, the switching valve 38 at time t ₅ is switched to the compressor 42 side, closing by the valve 64 is closed, the film 48 and the molded pulp 54 by the suction device 68 by the suction surface 44 of the housing 46, is caused to release from the mold 18a with increasing housing 46 at time t ₆ ~t ₇ followed . When increase of the housing 46 is completed, the rotary shaft 2 at time t ₇
4 of rotation is started, the period in time t ₈ for rotation together with the opening and closing valve 64 is opened, the rotation at time t ₉ is 1 cycle ends is terminated. In the present embodiment, the time t ₄ ~t ₅ described above corresponds to a suction process. The time of the suction step is set to, for example, about 10 seconds so that the moisture content becomes lower than 70%, for example, so that the pulp mold 54 is less likely to deform and can be easily handled. The released pulp mold 54 is sent to a drying device by a transport device (not shown), and further dried to a water content of about 10%. Since it is not necessary for understanding, a detailed description is omitted. Note that, in this embodiment, the suction device 68 uses the negative pressure means to start the rotation of the rotating shaft 24 and start the time from t _{1 to} t ₅ including the cover step and the suction step.
Corresponds to the dehydration step, respectively.

According to this embodiment, the pulp mold 54 on the molding surface 28 formed from the pulp slurry 14 by the molding die 18 has a negative pressure in the concave portion 26 and a negative pressure in the concave portion 60. In this state, the film 48 is covered by the film 48 provided on the suction surface 44, so that the film 48 is brought into close contact with the pulp mold 54 based on the pressure difference between the recess 26 and the recess 60. Then, since the film 48 is sucked toward the molding surface 28 by continuing the suction, the pulp mold 54 is squeezed by the film 48. For this reason, when the mold 18a comes out of the pulp slurry 14 while the suction is continued, the pulp mold 54 is dehydrated by the suction as in the conventional case, but the film 48 is adhered. Thereafter, the water contained in the pulp mold 54 is squeezed out by the squeezing effect, and a high dewatering ability is obtained. Therefore, the dewatering time until the moisture content is reduced to a level that facilitates handling is shortened, and high molding efficiency is obtained. Further, since the film 48 is brought into close contact with the pulp mold 54, the pulp mold 54 does not locally lose its shape due to the suction of the molding die 18, and the occurrence of defective products due to insufficient dehydration is eliminated. .

It is possible to perform the dewatering in a relatively short time even when it is desired to lower the water content, as in the case of dewatering the pulp mold 54 having a complicated shape.
% Moisture can be obtained by dewatering for about 1 minute. Further, when the same dehydration time as in the related art is used, the pulp mold 54 has an extremely low water content, and the pulp mold 54 is less likely to be deformed, and handling is further facilitated.

On the other hand, in the conventional pulp mold manufacturing apparatus, the pulp mold 54 adsorbed on the molding surface 28 is dehydrated only by suction from the recess 26. When the pressure is about 600 mmHg, the recess 26 is 1 in the suction step.
The pressure was reduced only to about 00 to 150 mmHg. Therefore, the dewatering efficiency is low, and it takes a long time (for example, 2 to 70%) to sufficiently lower the water content.
For about 10 minutes to reach a water content of about 65% for 1 minute)
This time, the pulp mold 54
Is longer than the adsorption time (for example, about 2 seconds), the molding speed is limited by the dehydration speed, and high molding efficiency cannot be obtained.

The through-hole 58 is provided in the membrane 48. Since the suction surface 44 has a shape substantially corresponding to the molding surface 28, when the film 48 is covered with the pulp mold 54, the suction surface 44 is formed. By making the film 48 substantially close to the molding surface 28 (that is, the distance between the suction surface 44 and the film 48 in a state where the film 48 is covered with the pulp mold 54 is relatively small), a portion other than the vicinity of the through hole 58 is formed. It is adsorbed on the pulp mold 54 surface. Therefore, the entire body is brought into close contact with each other, so that the compression ability due to the through hole 58 is hardly reduced, so that a sufficient compression effect can be obtained as described above.

Further, in this embodiment, the housing 4
6, since the release device 12 also functions as a cover device by providing the film 48 on the suction surface 44, as described above, when dehydration of the pulp mold 54 is completed, suction from the recess 26 is stopped, and Housing 46 as it is
The pulp mold 5 is sucked through the suction holes 56 of the pulp mold 5.
4 is adsorbed on the adsorbing surface 44 and released. Suction surface 4
A membrane 48 is provided between the pulp mold 4 and the pulp mold 54, and the membrane 48 is provided with a through hole 58 that communicates with a suction hole 56 provided on the suction surface 44.
The pulp mold 54 is sucked into the housing 46 through the membrane 48 by being sucked through the through hole 58. Therefore, according to this embodiment, there is no need to separately provide a cover device.

According to the present embodiment, the film 48 adsorbed on the surface of the pulp mold 54 is made of rubber, which is an elastic material, and the film 48 is deformed according to the shape of the pulp mold 54. It is not necessary to manufacture the mold 48 specifically according to the shape of the molding surface 28, and the molds 18a and 18b
Can have different shapes, and the same squeezing effect can be obtained on substantially the entire surface of the pulp mold 54. For example, a pulp mold 54 that cannot be squeezed by uniaxial pressing.
The squeezing effect is obtained even on a surface substantially perpendicular to the base 20, and the substrate 20 is sufficiently dehydrated.

In addition, the suction surface 44 of the housing 46 is separated from the pulp mold 54 in the dewatering step, and the pulp mold 54 must maintain a sufficient shape when it is sucked and released. Since it is dehydrated to the extent possible, it is not necessary to manufacture it particularly in accordance with the shape of the molding surface 28, and it is possible to correspond to a large number of molding dies 18 with a relatively simple shape.

Further, according to the present embodiment, the hanging film 50 that covers the side surface of the molding die 18 is provided in the dewatering process, so that the airtightness between the surface of the pulp mold 54 and the film 48 is kept high. At the same time, in the case of the molding die 18 in which pulp is also adsorbed on the side surface, the squeezing effect can be obtained by the dripping film 50.

Further, even when a hole is formed in a part of the pulp mold 54 in the suction step, the surface is covered with the film 48, so that the dewatering ability does not decrease. On the other hand, according to the conventional manufacturing method, the pulp mold 5
When a hole is formed in a part of the mold 4, the recess 26 and the pulp mold 54 are formed.
Since no pressure difference was generated between the surface and the surface, the dewatering ability was greatly reduced.

Further, according to the present embodiment, the surface of the pulp mold 54 at the time of molding (that is, the surface that normally becomes the outside during use) is pressed by the film 48, so that the surface is relatively smooth.

While the embodiment of the present invention has been described in detail with reference to the drawings, the present invention can be embodied in still another embodiment.

For example, as the non-permeable membrane, in addition to the rubber membrane 48, a resin sheet or a resin film, paper powder integrated with the pulp mold 54 by suction, glue, liquid resin, etc. May be used in the form of a sheet. The membrane 48 may be any material that is impermeable to air and generates a pressure difference between both surfaces of the membrane 48 by being sucked from the inside of the molding die 18 so as to be in close contact with the surface of the pulp mold 54. It is more preferable that the pulp mold 54 has elasticity to be deformed according to the shape of the pulp mold 54 adsorbed on the molding surface 28.

In the above-described embodiment, the release device 12 also serves as the cover device, but the cover device may be provided separately. For example, a film 48 made of rubber or the like having an area sufficiently larger than the molding surface 28 may be held by a frame or the like, and may be alternately moved up and down at the same position as the housing 46. In this case, since the pulp mold 54 is not adsorbed via the film 48 when the pulp mold 54 is released, it is not necessary to provide the through hole 58 in the film 48. Further, when a film integrated with the pulp mold 54 as described above is used, for example, when the mold 18 is rotated around the rotation axis 24, the film is temporarily stopped at a position rotated by 90 degrees, and a large number of films are removed. It is also possible to cover one of the membranes on the surface of the pulp mold 54 with a covering device provided.

The sagging film 50 is for improving airtightness and is not necessarily used. When provided, the hanging film 50 may be used integrally with the film 48.

In the above-described embodiment, the suction by the suction device 40 is continuously performed from the suction step to the end of the dehydration step. However, the suction may be temporarily stopped after the end of the suction step. That is, for example, even if suction is started again after the covering step is completed, the effect of the present invention can be obtained if suction is performed in a state where the pulp mold 54 is covered with the film 48 or the like. is there.

Further, in the above-described embodiment, the suction holes 3 perforated at a rate of one per cm ^{2 by} a drill or the like.
Although the molding die 18 provided with 0 is used, for example, a molding die made of a porous resin to which plastic particles are bonded may be used.

In the above-described embodiment, the molding die 1
Forming device 10 in which two are provided at positions 180 degrees different from each other
Was used, but a molding device 10 provided with only one molding die 18 and a molding device 10 provided with a large number of
May be used.

Although not specifically exemplified, the present invention can be variously modified without departing from the gist thereof.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a configuration of a pulp mold manufacturing apparatus according to one embodiment of the present invention.

FIG. 2 is an enlarged view showing a cross section of a molding die and a housing of the pulp mold manufacturing apparatus of FIG.

FIG. 3 is an example of a time chart when a pulp mold is manufactured using the pulp mold manufacturing apparatus of FIG. 1;

[Explanation of symbols]

 10: Molding device 12: Release device (also serves as cover device) 14: Pulp slurry 18: Mold 28: Molding surface 30: Suction hole 40: Suction device 44: Suction surface 46: Housing 48: Membrane (non-permeable membrane) 54: Pulp mold 56: Suction hole 58: Through hole

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-51-116212 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) D21J 3/00-7/00

Claims (3)

(57) [Claims] 1. An adsorption step of immersing a mold having a large number of suction holes opened in a molding surface into pulp slurry and sucking the pulp in the pulp slurry onto the molding surface by suction from the suction holes; A dewatering step of dewatering the adsorbed pulp, comprising the steps of: producing a pulp mold from the pulp slurry, wherein the dewatering step comprises, using a non-breathable membrane, the pulp adsorbed on the adsorption surface of the mold. A cover step for airtightly covering, and a pulp adsorbed on the molding surface of the mold is sucked from the suction hole in a state of being covered with the air-impermeable membrane , based on a differential pressure between atmospheric pressure and negative pressure. The non-ventilated film
A suction step of bringing the pulp into close contact with the pulp and pressing the pulp between the impermeable membrane and a mold. 2. An apparatus for producing a pulp mold from pulp slurry, comprising a mold having a plurality of suction holes opened in a molding surface, immersing the mold in the pulp slurry and suctioning through the suction holes. A molding device for adsorbing the pulp in the pulp slurry on the molding surface, and a cover device for airtightly covering the pulp adsorbed on the molding surface of the mold with the impermeable membrane. By sucking the pulp adsorbed on the molding surface of the molding die from the suction hole while being covered with the non-permeable membrane, the non-permeable membrane is formed based on the pressure difference between the atmospheric pressure and the negative pressure.
An apparatus for producing a pulp mold, comprising: suction means for bringing the pulp into tight contact with the pulp and for pressing the pulp between the air-impermeable membrane and a mold. 3. The non-ventilating device, wherein the cover device has a suction surface having a shape substantially corresponding to the molding surface and having a predetermined number of suction holes formed therein, and a through hole communicating with the suction holes is formed. When the suction period of the inside of the molding die by the suction means ends with the housing having the suction surface covered with the conductive film, the pulp mold on the molding die is released by sucking the pulp mold on the molding die by applying a negative pressure to the inside of the housing. 3. The pulp mold manufacturing apparatus according to claim 2, further comprising a negative pressure means.