JP3436798B2 - Pressure molding method of molding precursor - 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 for pressure-molding a molding precursor, and more specifically, to a molding precursor which has no bubbles inside and can be molded into a molded article having a beautiful surface. The present invention relates to a pressure molding method.

[0002]

2. Description of the Related Art Conventionally, a hydrostatic pressure molding method has been known as a method for pressure molding a powder or prepreg. In this hydrostatic pressure molding method, an object to be molded is housed or filled in a molding die formed of a flexible member such as rubber, and then the molding die is loaded into a pressurized chamber of a pressurizing device. This is a method of filling a pressurized chamber with a pressurized fluid such as a liquid at high pressure.

In such a hydrostatic pressure molding method, in order to achieve a highly depressurized state or a vacuum state inside the molding die at the time of pressure molding, the exhaust gas provided to the molding die before the pressure molding. The inside of the mold is exhausted from the mouth.

The reason for exhausting the inside of the molding die is as follows. That is, if the mold is pressed while gas remains in the mold, the surface of the molded body obtained after pressure molding may not be molded into a desired shape, or bubbles may be present in the molded body. Even if the surface of the molded body is apparently molded into a predetermined shape, if there are air bubbles inside the molded body, the molded body cannot maintain the predetermined strength,
In short, the strength is weak. Further, when the mold is pressurized while gas remains in the mold, the surface of the laminated sheet after pressure molding may not be molded into a desired shape when the object to be pressed is a laminated sheet, or , Bubbles may be present between the layers. When air bubbles are present between the layers in the laminated sheet, not only the strength is lowered, but also delamination occurs when the laminated sheet is used. Therefore, pressure molding is performed after the inside of the molding die is in a highly depressurized state or a vacuum state before pressurizing.

However, even if the inside of the mold is exhausted to a high degree before the pressure molding, the surface of the molded product obtained by the pressure molding is deformed and the bubbles are contained therein. Was not resolved as before.

The reason for this is that even if it is said that the molding die in which the object to be molded is loaded or filled is highly evacuated before the pressure molding, the gas trapped inside the object to be molded within a short time. It is extremely difficult to completely remove it, and in order to completely remove the gas trapped inside the object to be molded, it is necessary to continue exhausting the mold for an extremely long time, Even if it is possible to completely remove the gas in the mold, gas such as solvent vapor and decomposition gas contained in the object to be molded and decomposition gas of the binder are newly generated during pressure molding. It is thought that this is due to things.

In order to solve such a problem, for example, as described in Japanese Patent Publication No. 3-58525,
Before the pressure molding, the mold is highly exhausted, and the mold is highly depressurized or vacuumed, then the mold is pressed, and the mold is pressed even while the mold is being pressed. A new technology was developed to keep exhausting the inside.

However, according to the study by the inventors of the present application, even if the inside of the forming die is continuously evacuated during forming, it remains in the object to be formed when the forming die is made of a flexible member. The above problems due to gas are not yet solved, the exhaust port in the mold is blocked by the molding method that is a flexible member or the molding precursor itself, and the exhaust pipe is crushed when the pressure is particularly high. It was found that the exhaust was incomplete due to blockage.

The present invention has been made based on the above circumstances.
That is, an object of the present invention is to eliminate the above problems. Another object of the present invention is to completely exhaust the exhaust gas in the mold in which the object to be molded is loaded or filled. Another object of the present invention is to form a molded product having a desired surface condition without a recessed portion on the surface of the molded product, and without the occurrence of voids or cracks inside, and therefore,
An object of the present invention is to provide a pressure molding method capable of producing a molded product without delamination or reduction in strength. Another object of the present invention is to provide a pressure molding method capable of producing a pressure molded product with good yield.

[0010]

The invention according to claim 1 for solving the above-mentioned problems is provided in a mold comprising an air-impermeable flexible membrane and an exhaust port directed to the side. The molding precursor is accommodated, the inside of the molding die is maintained under reduced pressure, and the flexible fluid is pressurized by a pressurized fluid having a pressure fluctuation caused by repeating pressurization and pressure reduction to a minimum pressure value equal to or lower than atmospheric pressure at predetermined intervals. A method for press-molding a molding precursor, which comprises pressurizing the molding precursor in a vertical direction through a flexible film, wherein the pressurized fluid is a liquid.
A method for press-molding a molding precursor according to claim 1, wherein the invention according to claim 3 is the method for adding the molding precursor according to claim 1 or 2 , wherein the molding precursor is a ceramic green sheet. It is a pressure molding method.

The structure of the present invention will be described in more detail below.

-Molding Precursor- The molding precursor in the present invention can be contained or filled in a molding die, and as long as it can be formed into a molded product by pressurizing the molding die with a pressurized fluid. There is no particular limitation on the type. Preferable examples of this molding precursor include a prepreg comprising a reinforcing fiber, a semi-cured (sometimes referred to as B stage) thermosetting resin, and a solvent optionally used, a reinforcing fiber and a thermoplastic resin. And prepreg composed of a solvent optionally used, reinforcing fibers, ceramic particles, uncured resin, prepreg composed of a curing agent and a solvent, a powder containing ceramic as a main component, and a ceramic green sheet.

Examples of the reinforcing fibers in the prepreg include carbon fibers such as PAN-based carbon fibers and pitch-based carbon fibers, ceramic fibers, vapor-grown carbon fibers, and the like.

Preferable examples of the thermosetting resin include epoxy resin, unsaturated polyester resin, vinyl ester resin and phenol resin. As the thermoplastic resin, polyethylene, polypropylene, polystyrene, nylon, polybutylene terephthalate,
Examples thereof include ABS resin, polysulfone resin, polyphenylene sulfide resin, polyether sulfone, polyether ether ketone, and thermoplastic polyimide.

When the thermosetting resin is used, it is desirable to use a curing agent together.

The form of the prepreg is not particularly limited and may be a sheet form.

Examples of the ceramic include Al ₂ O ₃ and A
_{l 2 O 3 -TiC (TiN)} , BeO, MgO, lead zirconate titanate (PZT), Mn-Zn ferrite, Y _{3
Fe 5 O 12, ZrB 2,} Si 3 N 4, may be mentioned zirconia, mullite, SiO _2, aluminum nitride, or the like.

The ceramic-based powder may optionally contain known additives such as a solvent and a binder.

As the ceramic green sheet,
For example, an organic polymer or an inorganic polymer that changes into a ceramic by firing is added as a binder to a ceramic powder and / or a raw material for producing a ceramic, and if necessary, a solvent is added to a flexible sheet or film. The sheet formed by can be mentioned. Further, as the ceramic green sheet, a sheet having a small flexibility, which is formed using a raw material for producing ceramic powder and / or ceramic without using the binder or the solvent, can be mentioned. The ceramic green sheet may contain a reinforcing agent such as ceramic fiber.

-Molding die-The molding die according to the present invention is capable of accommodating an object to be molded therein, is provided with an exhaust port for removing the gas therein, and applies the pressure of the pressurized fluid to the inside of the molding die. There is no particular limitation as long as it is formed with a non-breathable flexible film that can be transferred to the molding precursor.

As a mold that can be used in the method of the present invention, for example, the molds described in Japanese Patent Publication No. 3-58524 and Japanese Patent Publication No. 3-58525 can be used. Further, a molding die as shown in FIG. 1 which is devised based on the molding die described in these publications can also be used. The molding die 1 shown in FIG. 1 is a bag formed of a plate-shaped frame body 3 having a rectangular opening 2 penetrating from the front side to the back side and a flexible member capable of housing the plate-shaped frame body 3. And a through hole 5 penetrating from the outer surface into the opening portion is provided on the short side of the plate-like frame body 3, and the bag body 4 has an exhaust port 6 corresponding to the through hole 5. And a large opening (not shown) for receiving the plate-shaped frame 3 therein.

A molding precursor is stored in the molding die 1 as follows. That is, for example, a thin plate (not shown) having the same plane area as the plate-shaped frame body 3 is inserted into the lower surface of the plate-shaped frame body 3 taken out from the bag body 4. By inserting this thin plate into the lower surface of the plate-shaped frame body 3, a bottom surface is formed in the opening 2. The ceramic green sheets 7 are housed one by one in the opening 2 having the bottom surface. After a predetermined number of ceramic green sheets 7 are accommodated in the opening 2, the plate-shaped frame body 3 together with the thin plates is inserted into the bag body 4 from the large opening portion (not shown) of the bag body 4. At the time of this insertion, it is essential to position and insert the plate-shaped frame body 3 so that the through hole 5 provided in the plate-shaped frame body 3 faces the exhaust port 6 in the bag body 4. Then, if necessary, the thin plate is pulled out from the bag body 4 so that the plate-shaped frame body 3 accommodating the ceramic green sheet 7 in the opening 2 remains in the bag body 4. The large opening of the bag body 4 is hermetically closed by an appropriate means.

As described above, a hermetically sealed body composed of the plate-shaped frame body 3 and the bag body 4 and having the ceramic green sheets 7 stacked and accommodated in the opening 2 of the plate-shaped frame body 3 is formed.

As is clear from the above description, the plate-shaped frame body having a sufficient space for housing the sheet-shaped molding precursor and the plate-shaped frame body can be housed in an airtight manner, A molding die including a bag body having a structure capable of highly exhausting the above is suitable for pressure molding a sheet-shaped molding precursor such as a green sheet.
In this molding die, the pressure at the time of pressure molding is such that the bag portion that covers the opening in the plate-shaped frame body becomes a flexible film, and the pressure is applied to the internal ceramic green sheet through this flexible film. Will be applied.

Another embodiment of the mold that can be used in the present invention is shown in FIG.

As shown in FIG. 2, another embodiment of the molding die is a plate-like frame body 13 having a rectangular opening 12 penetrating from the front to the back as shown in FIG. The plate-shaped frame body 13 is composed of a first flexible film 14a that covers the back side surface of the plate-shaped frame body 13 so as to close the opening 12, and a second flexible film 14b that covers the front side surface. Is the opening 12 and the first and second flexible films 14a, 1
Exhaust port 16 for exhausting the space formed by 4b
And the first and second flexible films 14a and 14b.
Is airtightly adhered to the side of the plate frame 13.

A molding precursor is attached to a molding die having a structure as shown in FIG. 2 as follows.

That is, as shown in FIG.
The first flexible film 14a on the back side of the plate-shaped frame 13 in FIG.
Is completely adhered so that no gap is formed on the adhesion surface between the first flexible film 14a and the plate-shaped frame body 13. As a result, the first flexible film 14 is formed in the opening 12 of the plate frame 13.
A bottom surface formed by a is formed. Next, the sheet-shaped molding precursor 17 is loaded into the opening 12 of the plate-shaped frame 13 to fill the opening 12. The second flexible film 14b is provided on the upper side surface of the plate-shaped frame body 13, and the plate-shaped frame body 13 and the second flexible film 14 are provided.
Adhere completely so that there is no gap on the surface to be adhered to b. As a result, the molding precursor 17 is hermetically sealed in the opening 12. The sealing is performed by pressing the flexible films 14a and 14b from the outside with a pressing tool (not shown). Alternatively, the outer side may be airtightly wrapped with a thin film leaving the exhaust port 16. This mold 1
Also in the first example, the pressure at the time of pressure molding is the first and second flexible films 1 that cover the openings 12 in the plate-shaped frame body 13.
Pressure will be applied to the molding precursor 17 inside via 4a and 14b.

Another embodiment of the mold which can be used in the present invention is shown in FIG.

The molding die 21 shown in FIG. 3 is arranged on the bottom surface of the base 24 having a concave portion 23 capable of accommodating a plurality of sheet-shaped molding precursors 22, and on the bottom surface of the concave portion 23. A first flexible film 25 that covers the bottom surface thereof in a liquid-tight manner, a second flexible film 26 that covers the upper opening of the recess 23 in a liquid-tight manner, and a second flexible film 26. A lid 27 for covering the upper opening of the concave portion 23 via
The bottom surface of the recess 23 and the first
First pressure fluid introducing channel 28 for introducing pressure fluid between the flexible membrane 25 and the second pressure fluid introducing channel 29 for introducing pressure fluid for applying pressure to the second flexible membrane 26.
And the first flexible film 25 and the lid 27 in the recess 23.
An opening 30 that opens to the inner wall surface of the recess 23 between
Air exhaust passage 3 for exhausting the air in the recess 23 from
1 and.

A pressure molding method using this molding die will be described later.

As another embodiment of the molding die which can be used in the present invention, "Reinforced Plastic Technology Association", "Reinforced Plastic Handbook", page 201, lines 1 to 13, and FIG. The molding die described in Kogyo Shimbun Publishing Co., Ltd. can be mentioned.

This mold has a male and female mold made of gypsum, FRP or sheet metal, a flexible film for covering the surface of the mold, and a space between the flexible film and the mold. And an exhaust port for exhausting.

A molding precursor is attached to the molding die as follows. That is, the molding precursor is arranged on the surface of either of the male and female molds, the molding precursor is covered with a soft film having a larger area than the molding precursor, and the end of the flexible film is clamped airtightly, Exhaust from the exhaust port.

As another embodiment of the molding die that can be used in the present invention, "Composite Material Engineering", edited by Takeshi Hayashi, No. 31
Figure 6.41 on page 1, page 312 lines 2 to 8
Molds, published by Nikkan Giren Publishing Co., Ltd., 7th edition, April 20, 1979 ”.

This molding die contains a mold having a recess for arranging a molding precursor arranged in a predetermined shape, a flexible member fitted in the recess, for example, a pressing plate made of silicone rubber, and the mold as a whole. And a flexible membrane bag.

A molding precursor is attached to the molding die as follows. That is, a predetermined number or a predetermined number of molding precursors having a predetermined shape are arranged in the concave portion of the mold, a pressing plate is arranged thereon, and the entire mold formed by mounting the pressing plate is placed in a bag of a flexible film. Accommodate.

The molding die described above is suitable mainly for pressure-molding a sheet-shaped or film-shaped molding precursor, and when the molding precursor is a powder, granules, etc., the molding described below. Molds are preferred.

A molding die as an example suitable for molding powder or the like is a metal cylindrical wire mesh body or a large number of through holes formed in the peripheral surface thereof, which is arranged in the cylindrical inner space of a pressure container for pressure resistance. Lids arranged above and below a metal cylinder provided with,
The metal cylindrical wire mesh body or a cylindrical flexible film disposed inside the metal cylinder body, and one or both of the pair of upper and lower lid bodies is provided with an exhaust port, The pressure vessel is provided with pressure medium introducing means for pressurizing the pressure medium into the cylindrical internal space.

In this molding die, a powdery or granular molding precursor is loaded into a cylindrical space formed by the lid and the flexible film.

-Pressure-Molding Method-In the pressure-molding method of the present invention, the molding precursor is contained in a molding die provided with an air-impermeable flexible membrane and an exhaust port, and the inside of the molding die is depressurized. The molding precursor is pressed through the flexible membrane with a pressurized fluid that is maintained below and has pressure fluctuations.

In the present invention, as described above, it is important to pressurize the forming precursor through the flexible film with a pressurized fluid having a pressure fluctuation while maintaining the inside of the forming die under reduced pressure. Is. If pressure is applied unilaterally without pressure fluctuation, the exhaust port and exhaust pipe communicating with the mold may be blocked, whereas if pressure force applied to the flexible membrane is fluctuated, low pressure is applied. Occasionally, the blockage is released, the blockage is not continuously blocked, and even if gas is generated by pressure molding of the molding precursor, for example, it is prevented that the exhaust port provided in the mold is blocked. The gas is completely exhausted, and a molded body free of voids, cracks, and bubbles can be obtained.

At the time of pressure molding, it is preferable to heat the molding precursor. The heating temperature varies depending on the type of the molding precursor, and for example, for a ceramic green sheet, it is usually 70 to 140 ° C., preferably 80 to 9 ° C.
0 ° C., usually 120 to 180 ° C. for normal epoxy prepregs, usually 20 to 80 ° C. for room temperature curable prepregs, uncured resin-containing ceramic reinforced ceramic prepregs or reinforcing fibers, ceramic particles, The prepreg consisting of uncured resin, curing agent, solvent and the like is usually at 150 to 220 ° C., the ceramic powder is at room temperature to 140 ° C., and the thermoplastic resin prepreg is at or above the flow temperature of the resin.

As for the heating time, when the molding precursor is a prepreg, it may take 30 minutes or more to cure the B-stage resin under pressure. When the molding precursor is a thermoplastic resin prepreg, the heating time may be shorter than 30 minutes.

The degree of exhaust pressure reduction in the molding die during pressure molding is preferably as high as possible, and is 1 Torr or less, preferably 0.1 Torr or less for ceramic green sheets and ceramic powder, but has high fluidity. Prepreg doesn't need to be very high vacuum, at least 20
Torr or less, preferably 5 Torr or less.

The fluid pressure at the time of molding is 1 to 5 atm, usually 1.5 to 3 atm for the prepreg containing the uncured resin, and 200 to 2,000 atm for the ceramic green sheet.
The pressure is preferably 350 to 400 atm, and the ceramic powder is 500 to 5,000 atm, preferably 1,000 to
It is 4,200 atm. Thermoplastic resin prepreg depends on the temperature, so high pressure does not require much pressure,
The higher the flow temperature, the higher the pressure required. However, up to 10 atm is sufficient.

For a prepreg containing an uncured resin, it is usual to continue heating and pressurizing for 30 minutes or more until it is cured. Other than that, it is within the range of 3 to 30 minutes, usually about 10 minutes for the ceramic powder and about 20 minutes for the green sheet.

The pressure fluctuation during the pressure molding is that the pressure in the molding die reaches a predetermined decompression degree, and the pressure applied to the molding die reaches a predetermined pressure, and then a predetermined pressure reduction is performed every predetermined period. It is possible to exemplify and perform predetermined pressurization and predetermined pressurization by a predetermined number of times. Also, after the pressure applied to the flexible membrane reaches a predetermined high pressure, it is maintained at that pressure for a predetermined time, then the applied pressure is reduced to a predetermined pressure, and the reduced pressure is maintained for a predetermined time. May be.

The fluid pressure at the time of depressurization is a pressure not lower than the mold internal pressure and higher than it, and not higher than 2 atm, preferably a pressure not lower than the mold internal pressure and higher than it, not higher than 1 atm. is there. However, normally, the fluid pressure during pressure reduction is returned to normal pressure. Also, it should be avoided that the pressure is equal to or lower than the pressure in the mold. This is because the sealing effect may be destroyed.

The pressure reduction time during pressure molding is usually 1 to 2 minutes.

The pressure applied to the molding die is usually a pressurized fluid.

Next, various aspects of pressure molding will be described.

For example, when the molding die having the structure shown in FIG. 1 is used, it is preferable to carry out pressure molding using a hydrostatic pressing device. As shown in FIG. 1, a molding die in which a plurality of ceramic green sheets are stacked and housed in an opening is housed in a pressurizing chamber of a hydrostatic pressing device. Here, the hydrostatic pressing apparatus includes, for example, a pressurizing chamber provided in a pressure resistant container, and a depressurizing unit that communicates with an exhaust port of a mold held in the pressurizing chamber to reduce the pressure in the mold. , Where the pressure medium is introduced into the pressurizing chamber, for example, a pressure medium introducing port opening into the pressurizing chamber, a pressure medium introducing passage continuous to the pressure medium introducing port, and a pressure medium in the pressure medium introducing passage. And a pressure medium introduction unit including a pressure medium supply pump. The forming die is housed in the pressurizing chamber of such a hydrostatic pressing apparatus, and the exhaust port of the forming die is connected to the pressure reducing means. And
The inside of the opening of the molding die in the pressurizing chamber is depressurized by the exhaust means, and the pressure medium is introduced into the pressurizing chamber by the pressure medium introducing means. After reaching a predetermined high pressure in the pressurizing chamber and reaching a predetermined depressurization in the molding die, after a predetermined time has elapsed, the pressure is cured, and the original pressure is further reduced in the state where the pressure is cured. Then, the pressure drop is repeated a predetermined number of times. At the time of this pressure molding, the ceramic green sheet may be heated to a predetermined temperature if necessary. At the time of pressure molding, a high pressure by a pressurized fluid is applied to the ceramic green sheet through a bag body formed of a flexible film to form a molded body. Even if gas is generated in the ceramic green sheet during this pressure molding, the generated gas is exhausted from the exhaust port by repeating the pressure drop.

After the elapse of a predetermined time, the pressure medium in the pressurizing chamber is discharged, and the depressurization inside the molded body is returned to normal pressure, whereby the pressure molding operation is completed.

The mold shown in FIG. 2 can also be pressure-molded by using the hydrostatic pressing device. In this case, in the molding die shown in FIG. 2, a pressure is applied to the molding precursor through the first flexible film and the second flexible film.

In the molding die shown in FIG. 3, a plurality of sheet-shaped molding precursors 22 are placed on the first flexible film 25 in the recessed portion 23 of the substrate 24 so as to overlap each other. The upper opening of the concave portion 23 accommodating a large number of molding precursors 22 is
It is covered with the flexible film 26 of FIG. The upper opening of the recess 23 covered with the second flexible film 26 is further covered by the lid 2
Cover with 7. The lid 27 is fixed by the fixing member 32. The fixing by the fixing member 32 fixes the lid 27 to the base body by the fixing member 32 so as to prevent the lid 27 from protruding from the upper opening portion when the molding precursor 22 such as the green sheet is pressure-molded. Alternatively, it can be realized by disposing the fixing member 32 on the upper end surface of the lid 27.

Next, the recessed portion 2 is removed from the air exhaust passage 31.
The air in 3 is exhausted to bring the inside of the recess 23 into a highly depressurized state. Simultaneously with the exhaust of the air or after the exhaust of the air is completed, the molding precursor 22 is
Pressure molding is performed.

That is, the pressure fluid is press-fitted between the first flexible film 25 and the bottom surface of the recessed portion 23 by the first pressure fluid introduction passage 28, and the second flexibility is made by the second pressure fluid introduction passage 29. A pressure fluid is press-fitted between the flexible film 26 and the lid 27.
As a result, the pressure applied by the pressure fluid introduced via the first flexible film 25 and the second flexible film 26 becomes
It is applied to a plurality of stacked molding precursors 22 to integrate the plurality of molding precursors 22. At this time, since the lid 27 is fixed to the plurality of stacked molding precursors 22 by the fixing member 32, the vectors facing each other by the first flexible film 25 and the second flexible film 26. Directional force acts.

During pressure molding with a pressure fluid, pressure reduction is repeated at predetermined intervals to cause pressure fluctuations due to the pressure fluid. After the pressure molding for a predetermined time is completed, the pressure of the pressurized fluid between the lid 27 and the second flexible film 26 is returned to the normal pressure, and at the same time, the bottom surface of the concave portion 23 and the first The pressure of the pressurized fluid with the flexible membrane 25 of No. 1 is returned to normal pressure. The fixation of the lid 27 by the fixing member 32 is released, and the lid 27 is removed from the upper opening of the recess 23. By the pressure fluid being pressed between the first flexible film 25 and the bottom surface of the recessed portion 23 by the first pressure fluid introduction flow path 28, the ceramic laminate, which is a molded body, is pushed out from the recessed portion 23. The extruded ceramics laminate is taken out from the recess 23.

Even when the molding precursor such as powder is pressure-molded, the inside of the molding die is essentially depressurized and the pressure is applied to the molding precursor in the molding die through the flexible film. By applying and varying the applied pressure, the pressure molding of the method of the present invention can be performed.

The pressure molding method of the present invention can also be carried out using the pressure molding apparatus shown in FIG.

The pressure molding device 50 shown in FIG. 4 is an end plug member having a pressure-resistant cylindrical body 51 having a circular horizontal cross section and a protrusion 52 which can be fitted into the lower opening of the cylindrical body 51. 53,
A pressure vessel main body 55, which is mounted in an upper opening of the tubular body 51 and includes a cover lid member 54 having an opening on the lower surface that has the same size as the horizontal opening of the tubular body.
The pressure container main body 55 is accommodated and a fixing member 56 having an opening portion for restricting the downward movement of the end plug member 53 at the time of pressure molding and at the same time regulating the upward movement of the cover lid member is provided.

The cylindrical body 5 on which the cover member 54 is mounted.
A non-breathable flexible film 57 is stretched over the upper opening of No. 1. A pressure medium passage 58 for introducing or discharging a pressure medium is opened on the inner peripheral surface of the cover lid member 54 in the opening or on the surface facing the flexible film 57 in the opening. The pressure medium is press-fitted into the opening of the cover member 54 from the pressure medium passage 58. The closed space formed by the opening of the cover member 54 and the flexible film 57 is also the pressure medium accommodation space 59 because the pressure medium is press-fitted from the pressure medium passage 58.

The cover member 54 and the tubular body 51 are usually integrally combined. In addition, the cover member 5 integrally connected
4 and the tubular body 51 are maintained in a fixed state without moving vertically or horizontally.

When the projecting portion 52 is fitted in the lower opening of the tubular body 51, the projecting portion 52 in the tubular body 51 is fitted.
A molding precursor 60 is provided in a space sandwiched between the flexible film 57 and the flexible film 57.
Is housed. Therefore, the inner space of the cylindrical body sandwiched by the flexible film 57 and the protruding portion 52 forms the molding precursor accommodating space 61.

Although not shown, an O-ring is fitted to the peripheral surface of the protruding portion 52 to ensure the liquid tightness of the protruding portion 52 fitted in the lower opening. The molding precursor accommodating space 6 is provided at an appropriate position on the peripheral surface of the protruding portion 52 above the position where the O-ring is fitted.
A gas introduction / exhaust passage 62 for exhausting the gas in 1 or for injecting the gas is opened. Even though the protrusion 52 is fitted in the lower opening of the tubular body 51, there is an extremely small clearance between the peripheral surface of the protrusion 52 and the inner peripheral surface of the tubular body 51. Even if the gas introduction / exhaust passage 62 is opened on the peripheral surface of the protrusion 52, the gas in the molding precursor accommodating space 61 can be sufficiently exhausted or the gas can be press-fitted. The opening where the gas introduction / exhaust path 62 opens is the exhaust port in the present invention.

The end plug member 53 is vertically movable and horizontally movable by a driving means (not shown). For example, the end plug member 53 starts from the state in which the protruding portion 52 is fitted in the lower opening of the tubular body, and
Is moved downward to move to a state in which it is arranged at an appropriate position below the lower opening, and further horizontal movement allows the end plug member 53 to move to a state retracted from the lower opening of the tubular body. You can do it.

On the other hand, the fixing member 56 is in contact with the upper horizontal member 56A having a lower surface in contact with the upper surface of the pressure vessel body 55, that is, the upper surface of the cover member 54, and the lower surface of the pressure vessel body 55, that is, the lower surface of the end plug member 53. And a lower horizontal member 56B having an upper surface,
It has a working opening 63 for housing 5. This fixing member 5
6 is horizontally movable so that the pressure vessel main body 55 can be accommodated in the working opening 63, or the working opening 63 can stand by at a position retracted from the pressure container main body 55.

A pressure molding method using this pressure molding apparatus 50 will be described. In the initial state, the fixing member 5
6 stands by at a position retracted from the pressure vessel main body 55. Further, the end plug member 53 stands by at a position retracted from the lower opening of the tubular body 51.

In this state, the molding precursor 60 is placed on the upper surface of the protrusion 52. When the end plug member 53 is horizontally rotated and the projecting portion 52 is located directly below the lower opening portion of the tubular body 51, the end plug member 53 is raised to move the projecting portion 52 into the lower opening portion of the tubular body 51. To fit.

When the protrusion 52 is fitted into the lower opening, if the pressure inside the molding precursor accommodating space 61 is reduced through the gas introduction / exhaust passage 62, the protrusion 52 is fitted into the lower opening. Is performed quickly (it may be said that the fitting is performed instantly). After the protrusion 52 is fitted in the lower opening, the fixing member 56 is moved horizontally, and the action opening 63 is formed.
The pressure vessel main body 55 is accommodated therein.

Next, the pressure medium is pressed into the pressure medium accommodation space 59 from the pressure medium passage 58. By press-fitting the pressure medium, pressure is applied to the molding precursor 60 via the flexible film 57. The pressure generated by the pressure medium acts on the end plug member 53 as a force that pushes down the end plug member 53, but the end plug member 53 is regulated by the lower horizontal member 56B of the fixing member 56, so the end plug member 53 is restricted. Since 53 cannot descend downward and the one end plug member 53 cannot descend, the pressure of the pressure medium acts as a force to raise the cover lid member 54, but the cover lid member 54 cannot rise. Since the upper horizontal member 56A of the fixing member 56 is restricted, the cover lid member 54 cannot rise. As a result, the molding precursor 6 is formed by the flexible film 57 and the upper surface of the protrusion 52.
0 is pressurized to high pressure.

By exhausting the gas in the molding precursor accommodating space 61 through the gas introducing / exhausting path 62,
The inside of the molding precursor accommodating space 61 is highly depressurized.

The pressure medium, which is press-fitted into the pressure medium housing space, is discharged or press-fitted from the pressure medium passage 58 to change the pressure of the pressure medium. The mode of this pressure fluctuation is as described above.

After the pressurization by the pressure medium and the depressurization in the molding precursor accommodating space 61 are maintained for a predetermined time, a gas is introduced into the molding precursor accommodating space 61 through the gas introduction / exhaust passage 62. While returning to normal pressure, the pressure medium accommodation space 59
The pressure medium press-fitted inside is discharged through the pressure medium passage 58 to remove the pressing force.

As a result, the fixing member 56 is horizontally moved to retract the pressure vessel main body 55 from the working space 63 in a state where the pressure applied by the pressure medium is substantially zero.

By driving the driving means (not shown) while pressurizing the gas into the molding precursor accommodating space 61 through the gas introducing / exhausting path 62, the end plug member 53 is lowered and the projecting portion 52 is pulled out from the lower opening. . At this time, the gas is press-fitted into the molding precursor accommodating space 61, so that the protrusion 52 can be pulled out from the lower opening very smoothly and quickly.

Further, preferably, when the protrusion 52 is pulled out from the lower opening, gas is pressed into the molding precursor accommodating space 61 and the pressure medium in the pressure medium accommodating space 59 is passed through the pressure medium passage 58. And remove by suction. That is, the inside of the molding precursor accommodating space 61 is brought into a pressurized state and the inside of the pressure medium accommodating space 59 is depressurized. In the pressurized state and the depressurized state, the flexible film 57 that has expanded to the side of the molding precursor containing space 61 during the pressure molding is pushed back to the original state. As a result, the flexible film 57 returns to the original flat state, and the next pressure molding can be started as it is. Moreover, when the protrusion 52 is pulled out from the lower opening of the tubular body 51, the flexible film 57 is not damaged by the tensile force.

The pressure molding apparatus shown in FIG.
Is attached to the lower opening of the tubular body 51, and the cover lid member 54 is coupled to the upper opening of the tubular body 51. As a modified example of the pressure molding apparatus shown in FIG. An example of the pressure molding device has a structure in which the end plug member 53 is attached to the upper opening and the cover lid member 54 is coupled to the lower opening of the tubular body 51. That is, a pressure molding device in which the pressure molding device shown in FIG. 4 is turned upside down can be cited as a modification. The pressure molding apparatus as this modification can achieve the same effects as the pressure molding apparatus shown in FIG.

In addition to the hydrostatic pressing device, the pressure molding device may be, for example, a "powder molding handbook",
For example, the rubber press device described in "Japanese Powder Industrial Technology Research Group" can be used.

In the above description, for simplicity, only the periphery of the mold is shown as a flat surface, but the present invention can be effectively applied even if the mold has a curved surface, and the spherical molded body and dome having no defect can be applied. Shaped body, lattice shaped body, pipe shaped body,
It is possible to mold a twisted surface molded body and the like.

-Molded Articles-According to the method of the present invention, various molded articles are manufactured depending on the structure of the mold. Molded articles manufactured by the method of the present invention include ceramic capacitors, large radar domes for aircraft, other aircraft parts, radar domes for submarines, sonar domes for submarines, IC packages, valve valve bodies, pump impellers, turbine blades, Examples include jet engine exhaust plugs and furnace materials. A known FRP molded product can also be molded by the method of the present invention.

[0083]

EXAMPLE A ceramic green sheet (140 mm × 140 mm × 2) having internal electrodes formed on a part of its surface
mm), that is, a laminated body formed by laminating 100 molding precursors 22 was loaded in the concave portion 23 of the molding die 21 having the structure shown in FIG. In this example,
The recess 23 in FIG. 3 has a horizontal cross section of 140 mm ×
A 140 mm square is formed, the depth of which is 10 mm, and one such recess 23 is provided in the base body 24.

After the laminated body was loaded in the recess 23, the opening of the recess 23 was closed by the second flexible film 26, and the lid 27 was attached to the base opening. The press device main body including the base body 24 and the lid body 27 was positioned at the opening of the frame yoke, that is, the fixing member 32.

Next, the concave portion 2 is removed from the air exhaust flow path 31.
The inside of 3 was evacuated to 0.1 Torr, and then the evacuation operation was stopped, but the inside of the concave portion 23 was maintained at the above-mentioned degree of pressure reduction. Under such a condition, the temperature of 80 ° C. is reached via the first pressure fluid introduction flow passage 28 and the second pressure fluid introduction passage 29.
The pressure fluid of No. 3 was injected under pressure to apply a pressure of 300 atm to the first flexible film 25 and the second flexible film 26. The pressure of the pressure medium was maintained at 300 atm for 15 minutes, and then the pressure was released to obtain a pressure molded product (hereinafter, referred to as one cycle pressure molded product). The cycle of pressurization and depressurization at this time is one cycle.

Separately, pressurization and depressurization were repeated for two cycles in the same manner as above to take out a pressure-molded product (hereinafter referred to as 2-cycle pressure-molded product), and separately, exactly the same as above. Then, pressurization and depressurization were repeated for 3 cycles to take out a press-formed product (hereinafter referred to as a 3-cycle press-formed product).

As described above, the two 1-cycle pressure-molded products, the two 2-cycle pressure-molded products and the two 3-cycle pressure-molded products were each cut into a product of about 5 mm □ and 100 A sample was taken and baked in a baking furnace at 450 ° C. for 3 days and then at 1,300 ° C. for 4 hours. The laminated cross section of each sample was examined with an optical microscope for the presence of cracks between layers. If even one crack was found, the laminate was evaluated as a defective product.

There are 19 defective products out of 100 samples for the 1-cycle pressure molded product, and 7 defective products out of 100 samples for the 2-cycle pressure molded product.
2 out of 100 samples for 3-cycle pressure molded products
There were defective products. From these results, by repeating pressurization and depressurization when press-molding the molding precursor,
In other words, it is understood that when pressure fluctuation is caused during pressure molding, defective products can be prevented from being produced and products can be manufactured with high yield.

[0089]

According to the present invention, even if a gas is generated from a molding precursor or a binder during pressure molding, it is possible to manufacture a pressure-molded article having no bubbles or cracks.

[Brief description of drawings]

FIG. 1 is a partially cutaway perspective view showing an exemplary mold used in the method of the present invention.

FIG. 2 is a cross-sectional view showing an example molding die used in the method of the present invention.

FIG. 3 is an explanatory view showing a pressure molding apparatus as an example used in the method of the present invention.

FIG. 4 is an explanatory view showing a pressure molding apparatus as an example used in the method of the present invention.

[Explanation of symbols]

1 ... Mold, 2 ... Opening part, 3 ... Plate-shaped frame,
4 ... bag body, 5 ... through hole, 6 ... exhaust port, 7 ...
..Ceramic green sheets, 11 ... Molds, 1
2 ... Opening part, 13 ... Plate-shaped frame body, 14a ... 1st flexible film, 14b ... 2nd flexible film, 16 ...
・ Exhaust port, 17 ... Molding precursor, 21 ... Mold,
22 ... Molding precursor, 23 ... Recessed portion, 24 ...
Substrate, 25 ... First flexible film, 26 ... Second flexible film, 27 ... Lid, 28 ... First pressure fluid introduction channel, 29 ... Second pressure fluid Introducing channel, 30 ... Opening section, 31 ... Air exhaust channel, 32 ... Fixing member,
50 ... Pressure molding device, 51 ... Cylindrical body, 52 ...
・ Projection part, 53 ... End plug member, 54 ... Cover member,
55 ... Pressure vessel main body, 56 ... Fixing member, 57 ...
..Flexible membrane, 58 ... Pressure medium passage, 59 ... Pressure medium containing space, 60 ... Molding precursor, 61 ... Molding precursor containing space, 62 ... Gas introduction / discharge passage, 63.
..Working openings.

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hisao Matsuno 3-43-2 Ebisu, Shibuya-ku, Tokyo Inside Nikkiso Co., Ltd. (56) Reference JP-A-51-103910 (JP, A) JP-A-1-123702 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) B29C 43/12 B28B 3/00 102

Claims (3)

(57) [Claims] 1. A non-breathable flexible membrane and sideways
The molding precursor is housed in a molding die having an exhaust port, the inside of the molding die is maintained under reduced pressure, and pressurization and pressure reduction to a minimum pressure value below atmospheric pressure are repeated every predetermined period. A method for press-molding a molding precursor, which comprises pressurizing the molding precursor in the up-down direction through the flexible film with a pressurized fluid having a pressure fluctuation. Wherein said pressurized fluid is a liquid claim 1
The method for pressure-molding a molding precursor according to item 1. 3. A press-molding method of the molded precursor wherein the molded precursor to claim 1 or 2 is a ceramic green sheet.