JP5708058B2 - Fiber reinforced plastic molding method - Google Patents

Description

  The present invention relates to a molding method for producing a molded body of fiber reinforced plastic (FRP) having a closed cross section by heating and pressurizing a prepreg in which fibers are impregnated with a resin using a core.

  Fiber reinforced plastic moldings with closed cross-sections are widely used, ranging from large molded bodies such as aircraft fuselage and wings to small molded bodies such as bicycle frames, tennis rackets, fishing rods and golf shafts. Yes. In addition, as a fiber reinforced plastic molded body having an open cross section, it is widely used in helmets and the like.

  As a core for forming a closed cross section, a core formed by wrapping a powder body with a packaging film and vacuum-packaging and forming a predetermined shape, a core formed by blow molding, or the like is used. As a core in which a vacuum packed packaged powder body is formed in a desired shape, a multilayer plastic molded body and its manufacturing method (see Patent Document 1) have been proposed, and as a core formed by blow molding, A multilayer plastic molding and its manufacturing method (see Patent Document 2) have been proposed.

  The invention described in Patent Document 1 will be described as Conventional Example 1 of the present invention with reference to FIGS. FIG. 8 shows a state in the middle of manufacturing a molded product having a hollow portion which is a kind of closed section by the molding die 30. That is, a sheet-like fiber reinforced thermoplastic resin material (FRTP) 34 that has been preheated to a molten state is placed on the lower mold 31 of the molding die 30. Since the FRTP 34 is in a molten state, the FRTP 34 hangs down due to its own weight and sinks into the recess of the lower mold 31.

  The core 33, in which the powder 33a is wrapped with a packaging material 33b and solidified into a predetermined shape by vacuum pack packaging, is placed in the recess of the FRTP 34. A new sheet-like FRTP 35 heated to a molten state is placed on the FRTP 34 on which the core 33 is placed. In this state, the periphery of the core 33 is surrounded by FRTP 34 and FRTP 35.

  From this state, the upper mold 32 of the molding die 30 is lowered and the FRTP 34 and FRTP 35 are heated and cured between the lower mold 31 and the FRTP 34 and FRTP 35 with the core 33 contained therein. It can be molded integrally. In order to discharge the core 33 from the finished semi-molded product, a small hole is made in the semi-molded product. When a hole is made in the semi-molded product, air enters between the powder particles 33a of the core 33 vacuum-packed, and the binding between the powder particles 33a is loosened.

  And the granular material 33a which comprised the core 33 can be discharged | emitted out of a semi-molded product through the hole formed in the semi-molded product, and a molded product can be completed. At this time, if the packaging material 33b in which the powder 33a is vacuum-packed is made of a material having good peelability with respect to the molded product, the packaging material 33b can also be removed from the molded product.

  The invention described in Patent Document 2 will be described as Conventional Example 2 with reference to FIG. FIG. 10 shows a state in which the core 43 molded by blow molding is set between the molding dies 41a and 41b for forming the outer layer. As shown in FIG. 10, the molding dies 41a and 41b are configured to accommodate the core 43, and when the molding dies 41a and 41b are clamped, the molding dies 41a and 41b are formed. A cavity serving as a hollow portion for filling the molten resin is formed between the mating surfaces 42a and 42b and the core 43.

  The molten resin 45 plasticized by the extruder 44 is supplied into the cavity. By supplying the molten resin 45 into the cavities of the molding dies 41a and 41b in the clamped state, a product having a hollow portion can be shaped into a desired shape. However, when the product is shaped, if the heat resistance of the core 43 is low with respect to the temperature of the molten resin, or if the thickness of the core 43 is thin, the pressure applied to the core 43 during shaping As a result, the core 43 may be deformed. Further, if there is a wide flat portion in the shape of the core 43, the flat portion is insufficient in rigidity, and the core 43 may be similarly deformed.

  In order to prevent the deformation of the core 43, the invention described in Patent Document 2 is configured such that the internal pressure of the core 43 can be increased. For this purpose, a pressurizing unit 46 communicating with the core 43 is provided. By introducing pressurized gas or liquid into the core 43 from the pressurizing unit 46, the internal pressure of the core 43 is reduced. Can be raised.

JP-A-2-238912 JP-A-7-1000085

  In the invention of Patent Document 1, the upper die 32 is lowered with the core 33 sandwiched between the FRTP 34 and the FRTP 35, and the FRTP 34 and the FRTP 35 are pressurized between the upper die 32 and the lower die 31. However, when the core 33 is placed in the recess formed in the FRTP 34 by sinking into the recess of the lower mold 31, or when the FRTP 35 is placed over the core 33, the corners of the recess of the lower mold 31 are reduced. A gap is generated between the part and the FRTP 34, or between the core 33 and the FRTP 34 and FRTP 35.

  If the upper mold 32 and the lower mold 31 are heated and pressurized with this gap remaining, the FRTP 34 and FRTP 35 cannot be sufficiently supported from the inside by the core 33, and in particular, the upper mold 32 In the part of FRTP34 molded in the same direction as the vertical direction in which the metal moves, that is, in the vertical part, the thickness changes, and further, the outer peripheral surface shape of FRTP34 is changed to the corner shape in the recess of the lower mold 31. It cannot be formed in a shape along the line, and is formed into a shape that is wrinkled on the outer surface or buckled in the vertical direction. Or the length dimension in a vertical part is shape | molded in the state compressed into the length dimension shorter than a regular length dimension, and the dimensional accuracy of a product will fall.

  In particular, when FRTP34 and FRTP35 are made of a long fiber reinforced resin material using long fibers, between the core 33 and FRTP34 and FRTP35, or between the upper mold 32 and lower mold 31 and FRTP34 and FRTP35. When pressure molding is performed with the voids present, the fiber orientation of the long fibers is disturbed and bending occurs, leading to a decrease in strength as a fiber-reinforced plastic and a deterioration in the appearance of the molded product.

This will be described in more detail with reference to FIG. 9 schematically showing the configuration of Conventional Example 1. In FIG. 9, the vertical portion described above is indicated by reference numeral 37. An annular prepreg 36 in which a fiber having a core 33 disposed therein is impregnated with resin is housed in a recess formed in the lower mold 31, and the upper mold 32 is lowered toward the lower mold 31. ing.

  As shown in FIG. 9, a semi-molded product can be manufactured by sandwiching a prepreg 36 between an upper mold 32 and a lower mold 31 and applying heat and pressure. Then, a hole is formed in the completed semi-molded product, and the particles forming the core 33 are discharged out of the hole formed in the semi-molded product, whereby a hollow molded product is completed.

  However, when the core 33 is placed in the recess formed in the prepreg 36 housed in the lower mold 31, when the semi-molded product is shaped into a shape having a corner, the core 33 at the corner A gap is generated between the outer peripheral surface and the inner peripheral surface of the prepreg 36. In particular, in order to smoothly put the prepreg 36 into the molding die, there will be some space between the molding die and the prepreg 36, and similarly between the corners on the molding surface and the prepreg 36. A void is likely to occur.

  Then, when the upper mold 32 is lowered toward the lower mold 31 and the prepreg 36 is heated and pressurized, due to the influence of this gap, wrinkles and bending may occur in the vertical portion 37 of the prepreg 36, or the prepreg 36 In this case, the corners on the outer surface side are not formed in a desired right-angled shape, and are not filled.

  In particular, the amount of the powder that constitutes the core 33 is small, a gap is formed between the prepreg 36 and the core 33, and bending occurs in the vertical portion 37 of the prepreg 36. As a result, as shown in FIG. 9, a part of the vertical portion 37 is deformed into a shape curved toward the core 33 side. In addition, when the powder particles constituting the core 33 have low fluidity, the influence of deformation becomes significant. And as shown in FIG. 9, even if a part of the vertical part 37 is not deformed into a shape curved toward the core 33 side, the length dimension in the vertical part 37 is shorter than the prescribed length dimension. It will be compressed to the length dimension.

  In the invention of Patent Document 1, in order to prevent generation of defective products, the preform accuracy of the prepreg 36 is improved or the core 33 is prevented so that no gap is formed between the prepreg 36 and the core 33. It is necessary to form such that the desired shape becomes a desired shape. However, it is configured by accurately measuring the amount of powder and particles constituting the core 33, forming the shape into a desired shape, closely contacting the prepreg 36 with the core 33, and further forming the outer shape of the prepreg 36. Aligning the inner shape of the molding die with the powder is not completely fixed or the prepreg is not hardened, which requires a lot of labor and a long time. become.

  In the invention described in Patent Document 2, the internal pressure of the core 43 can be increased by introducing a pressurized gas or liquid. In a pressurized gas or liquid, the pressure at an arbitrary point has the physical property of being the same pressure in all directions. For this reason, when a part of the gas or liquid pressurized to increase the internal pressure leaks from the core 43, the leaked gas or liquid becomes a high-speed, high-pressure jet flow, and the high-temperature state As it is, it will be ejected from the gap between the molding dies 41a and 41b. In particular, when liquid is ejected, there is a risk of causing serious damage around the molding die or causing harm to the worker, so equipment with sufficient safety measures is required. .

  Thus, as in the inventions described in Patent Documents 1 and 2, for example, hydraulic cylinders that can withstand the required internal pressure are normally used for opening and closing operations of the upper molds 32 and 41b, which are movable, and the expansion / contraction distance is as follows. It is controlled to keep the distance between the upper die and the lower die constant during molding. However, it is possible to withstand the increase in the pressing force by the outer surface of the prepreg with respect to the inner surface of the upper mold accompanying the increase in the inner pressure of the core during molding, and to maintain the position of the upper mold constant, that is, between the upper mold and the lower mold. It becomes difficult to keep the interval constant. As a result, the molded product as a product does not have a predetermined size, and there are many dimensional variations, leading to a decrease in yield.

  The present invention solves the above-mentioned conventional problems and can uniformly increase the pressure between the prepreg and the core without using gas or liquid when molding a molded product having a closed cross section by a molding die. In addition, even if pressure is applied to the core, or even when a normal molding die is used, a part of the medium constituting the core does not leak from the molding die. It aims at providing the molding method of the fiber reinforced plastic excellent in dimensional accuracy.

To achieve the above object, in the method of molding a fiber reinforced plastic of the present invention, the deformable core into a desired shape a large number of the granules were housed in a flexible bag having fluidity, fibers Interposing inside the prepreg impregnated with resin , arranging the prepreg containing the core between the upper mold and the lower mold of the molding mold, and clamping with the molding mold Alternatively, at the time of pressure molding, holding the mold interval holding means so that the distance between the upper mold and the lower mold does not widen, and pressing means protruding and retracting toward the cavity between the upper mold and the lower mold, Adhesiveness between the prepreg, the mold and the core by pressing a part of the outer peripheral surface of the core to increase the inner pressure in the core to be deformed and by pressing deformation of the core Is the main component.

  Further, according to a preferred embodiment of the present invention, a fitting protrusion for fitting into the cavity is provided on the mold surface opposite to the side where the pressing means is disposed across the prepreg, The core is sandwiched between the fitting protrusion and the pressing means constituting a part of the molding surface of the molding die at the time of mold clamping or pressure molding by the molding die. Pressing a part of the outer peripheral surface of each.

  More preferably, the mold interval holding means is arranged on the left and right sides of the upper mold, and the mold interval holding means arranged on the left and right sides of the upper mold is moved by a predetermined amount in a direction approaching each other. To completely restrict the upward movement of the upper mold. It is preferable that the left and right side surfaces of the upper mold and the contact surface of the mold interval holding means are relatively wedge-shaped sliding surfaces. Preferably, the pressing means includes a hydraulic cylinder, and a part of the outer peripheral surface of the core is pressed so as to sandwich the core by an expansion and contraction operation of a piston rod of the hydraulic cylinder.

  In the present invention, a core in which a large number of granules having a high fluidity are formed in a desired shape is used. In addition, a depression is formed on the outer peripheral surface of the core by pressing a part of the outer peripheral surface of the core through the prepreg or not through the prepreg during the compression molding by the molding die. The internal pressure is forcibly increased. Then, by increasing the internal pressure of the core, slip is generated between the particles constituting the core, and the core is deformed.

  Thereby, even if a gap is formed between the prepreg enveloping the core and the core, the gap can be filled and eliminated by deformation of the core. In particular, even if a gap is formed between the corner of the molding surface of the molding die and the prepreg, the prepreg can be moved in the direction of filling the gap by deformation of the core due to the movement of the particles. And voids can be eliminated. That is, the adhesion between the prepreg, the mold and the core can be improved.

  The gap formed between the prepreg and the core due to the deformation of the core is crushed by the deformation of the core, or the air constituting the gap is released from the molding die through the prepreg into the atmosphere. Will be. The passage formed when the air passes through the prepreg is naturally blocked by the molten prepreg after the air passes through.

  The core is configured to be deformable into a desired shape in which a large number of particles are accommodated in a flexible bag. For this reason, even if the outer peripheral surface of the core is pressed to form a depression on the outer peripheral surface and deformed, the internal pressure in the core is normally all the parts as in the case of using liquid or gas. In the same pressure state. That is, even if pressure is applied to the particles, a pressure smaller than the pressure at the portion where the pressure is applied is generated at the other portion. And when the applied pressure exceeds a certain value, slip occurs between the particles.

  Therefore, when the outer peripheral surface of the core is pressed, the outer peripheral surface of the core away from this portion even if the internal pressure there is greatly increased in the portion where the depression is formed in the outer peripheral surface of the core by pressing. The pressure increase at the site on the side is lower than the pressure increase at the site where the depression is formed.

  In particular, the pressure transferability within the core and the fluidity of the particles are affected by the roughness of the particle surface and the particle diameter of the particles. When particles having a uniform particle diameter are used, the particles are packed most closely in the core, the fluidity of the particles is hindered, and the pressure transferability is impaired. Therefore, considering the particle size distribution in the core and the particle surface roughness distribution, or using a combination of particles with different particle sizes, the fluidity and pressure of the particles in the core Improves transmission.

  As a core, if it has the above-mentioned function, a raw material will not be limited. That is, the flexible bag may be selected from materials that can be appropriately deformed without being broken at a required pressure. In addition, as for the granule, a material that can flow appropriately without being deformed or broken at a necessary pressure may be selected and used. In addition, it is preferable to form a core by wrapping a large number of particles with a flexible packaging film and performing vacuum pack packaging because the shape accuracy of the core can be improved.

  Even in the part away from the part where the depression is formed by the pressing, the core is deformed by the sliding of the granule. As a result, the prepreg can be pressed along the molding surface of the molding die, and for example, the pressure between the core portion supporting the vertical portion as described above and the prepreg can be increased. it can. Further, it is possible to prevent the vertical portion as described above from being bent and deformed during pressurization by the upper die and the lower die.

  At this time, the pressing force by the prepreg on the mold surface increases, but when the pair of left and right mold interval holding means is moved horizontally by a predetermined distance in the approach direction, the upper mold comes into contact with the upper mold in the middle. Further upward movement is prevented, and a predetermined distance is maintained between the upper mold and the lower mold in the vertical portion described above. In this way, the clamping position of the molding die is fixed, and an increase in pressing force between the outer peripheral surface of the core and the inner surface of the prepreg is ensured. As a result, it is possible to avoid the occurrence of a situation in which the length dimension in the vertical direction at the vertical portion as described above is shortened by being compressed to a predetermined dimension or less, and the prepreg can be formed to a desired thickness. At this time, if there is no means for holding the mold interval and the vertical movement of the upper mold is controlled only by the hydraulic cylinder, the pressure rise due to expansion of the core becomes more than specified, and the upper mold is moved up against the cylinder. As a result, the distance between the upper and lower molds is increased, and a product having a height higher than a prescribed dimension is manufactured.

  Incidentally, as a suitable example of the mold interval holding means, it is preferable to employ a wedge surface. According to a specific aspect, the upper end shoulders of the left and right side surfaces of the upper mold are formed on the lower inclined surface facing outward, while the lower end corners of the opposing surfaces of the pair of left and right mold interval holding means are also facing outward. Formed on the lower inclined surface. For example, after moving the mold interval holding means horizontally in the approaching direction, the facing inclined surfaces of the upper mold and the mold interval holding means are in contact with each other, and then the left and right mold interval holding means are further moved in the approaching direction. If it does, the inclined surface of a metal mold | die space | interval holding means will push the inclined surface of an upper mold | type according to the movement amount, and will move an upper mold | type downward. Here, when the left and right mold interval holding means are stopped, the upper limit movement position of the upper mold is determined, and the upper mold is restricted from moving further upward. Therefore, the upper mold maintains the movement limit position even when the pressing force against the cavity surface of the upper mold received from the core via the prepreg is increased.

Therefore, even when there are corners on the outer peripheral surface of the prepreg, for example, when forming a right-angled corner, it is possible to move a sufficient amount of the prepreg to the corner of the molding die for molding the corner. Therefore, the outer shape of the prepreg can be surely formed.
Here, when the internal pressure of the core is increased, each granule moves while sliding in the front-rear and left-right directions, but the flexible bag containing each granule, such as a packaging film, is made of a material that can be extended. It is configured. Therefore, the bag body can permit deformation of the outer shape of the core accompanying the movement of each particle.

  Temporarily, when the pressure of the granule is increased by clamping the molding die or pressing to form a depression, the flexible bag is not strong enough to hold the granule against the pressure. The flexible bag may be broken. If the gap between the molding dies is smaller than the diameter of the particles, it will not leak out of the molding dies unless the particles are crushed.

  As a means for pressing a part of the outer peripheral surface of the core, a piston rod that can be freely moved into and out of the molding surface of the molding die can be used. Here, piston rods that can freely move in and out of the molding surface of the molding die can be arranged at a plurality of portions, and a plurality of pressing portions can be provided.

  In the present invention, when the outer peripheral surface of the core is pressed, a part of the outer peripheral surface of the core can be pressed through the prepreg or without the prepreg. When pressing through a prepreg at a portion having a substantially planar shape, a recess is formed in the prepreg. When pressing through the prepreg at the convex portion, the prepreg becomes flat. Except for the depressions and flat portions, which are the pressing parts, and the pressing part, a discharge hole for discharging the particles constituting the core from the molded product can be provided.

  In addition, when pressing a part of the outer peripheral surface of the core without going through the prepreg, a hole corresponding to a pressing portion such as a rod is opened in the prepreg and pressed directly on the core, The flexible bag is broken from the hole position, and the particles are discharged. The flexible bag body can be removed by performing a release treatment such as applying a release material, or by forming a double package, so that the flexible bag body can be removed.

It is a schematic diagram which shows the time of pressure molding in Example 1 of this invention. FIG. 3 is a schematic diagram showing an internal structure of a prepreg and a core in Example 1. It is a schematic diagram which shows an example of the shaping | molding process of a hollow molded product. 6 is a schematic diagram showing the time of pressure molding in Example 2. FIG. 6 is a schematic diagram showing the time of pressure molding in Example 3. FIG. It is a schematic diagram which shows the structural example of the metal mold | die space | interval holding | maintenance means in this invention. It is explanatory drawing which shows the relationship between an internal pressure and a stroke. It is explanatory drawing which shows the state at the time of shaping | molding of the molded article which has the hollow unusual cross section using the conventional core. It is a schematic diagram which shows the time of pressure molding of FIG. It is sectional drawing which shows a state when a core is set between the conventional molds.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be specifically described with reference to the accompanying drawings by way of typical examples. Here, the molding method of the fiber reinforced plastic according to the present invention is not limited to the examples described below, and a constant interval is maintained without increasing the interval between the upper die and the lower die at the time of molding. Any structure can be applied to the present invention as long as the core can be deformed with a pressure of 2 mm.

  As shown in FIG. 1, the prepreg 3 containing the core 4 is formed into a shape substantially the same as the inner peripheral surface shape of the molding die 15 at room temperature, and this is heated in advance to form the molding die 15. It is placed in the recess 1a formed in the lower mold 1.

  The prepreg 3 is formed in a sheet shape in which carbon fiber, glass fiber, aramid fiber, silicon carbide fiber or the like is impregnated with uncured thermosetting resin or thermoplastic resin. In the illustrated example, the prepreg 3 is formed in a cylindrical shape in cross section, and a core 4 is interposed inside. For example, the core 4 is wrapped between two sheet-like prepregs. Then, by heating the molding die, the prepreg 3 containing the matrix resin in a flowable state is cured by pressure molding in the molding die 15 composed of the lower mold 1 and the upper mold 2. Various shaped fiber reinforced plastic (FRP) molded articles having hollow portions having a desired shape can be formed. When impregnated with a thermoplastic resin instead of a thermosetting resin, the preform formed by preheating the prepreg 3 is pressure-cooled with a molding die, and an FRP molded product having a desired shape is obtained. Can be manufactured.

As a molded product of fiber reinforced plastic (FRP), in the illustrated example, the cross-sectional shape has a rectangular shape, but the molded product of fiber reinforced plastic (FRP) is not limited to such a shape, and is curved. It can be formed into a cross-sectional shape combined with a shape or the like.
As the thermosetting resin impregnated into the fiber, epoxy resin, urea resin, vinyl ester resin, unsaturated polyester, polyurethane, phenol resin, etc. can be used, and as thermoplastic resin, polypropylene, polyethylene, polystyrene, chloride, etc. Vinyl, polyamide resin, etc. can be used.

  The core 4 is formed in a desired outer shape by packaging the particles 4a with a packaging film 4b and vacuum-packing them. The granules 4a constituting the core 4 are made of particles such as ceramics such as alumina and zirconia, glass, hard heat-resistant resin, metal, foundry sand, quartz, etc., and the packaging film 4b used for maintaining the shape of the core 4 For example, a nylon film, a polyethylene film, a fluororesin film, or silicone can be used. In particular, when zirconia or quartz is used as the particles 4a, these materials have a low thermal conductivity, and therefore are suitable materials for the particles 4a of the core 4.

  According to the illustrated example, a cylinder 5 having a piston rod 5 a that can be projected and retracted in the cavity of the molding die 15 is provided in the recess 1 a of the lower mold 1. In FIG. 1, the piping for supplying and discharging the working fluid to and from the pressure chamber of the cylinder 5 for sliding the piston rod 5a is omitted. The upper mold 2 and the lower mold 1 can be moved in directions close to each other to clamp the mold, and the prepreg 3 placed in the recess 1a of the lower mold 1 can be heat-cured. At this stage, the pressure is not high. In the next stage, the piston rod 5a is extended to increase the internal pressure while deforming the core 4, and at the same time, the prepreg 3 is also deformed along the molding surface of the molding die 15. . At this time, in order to increase the pressure between the core 4 and the molding die 15, it is only necessary to provide an opening / closing mechanism for the upper and lower molds 2, 1 as the mold clamping machine, and no special high-pressure press machine is required.

  When the upper mold 2 and the lower mold 1 are clamped, or when the prepreg 3 is pressurized with the upper mold 2 and the lower mold 1 with a predetermined pressure, the upper mold 2 and Make sure that the distance from the lower mold 1 does not increase further. Therefore, according to the illustrated example, the upper mold 2 is provided with mold interval holding means 20 for holding the distance between the upper and lower molds 2 and 1 constant. As shown in FIG. 1, when the core 4 is pressed and deformed by the piston rod 5a, the upper die 2 is increased by the increase in the pressing force due to the deformation of the prepreg 3 relative to the upper die 2. The configuration that does not lift is adopted.

In the example shown in FIG. 1 and FIG. 6 (A), the mold interval holding means 20 includes lower inclined surfaces 2a, 2a formed on left and right side upper ends (upper left and right shoulders in FIG. 1) of the upper die 2. A pair of left and right pressers that have wedge surfaces 21b, 21b that are in sliding contact with the lower inclined surfaces 2a, 2a in a surface contact state and are slidable in a direction (horizontal direction) perpendicular to the moving direction (vertical direction) of the upper mold 2 The members 21a, 21a and a drive unit (not shown) for moving the pressing members 21a, 21a in the horizontal direction and driving them in the approaching and separating directions are provided. As shown in FIG. 6A, the shape of the opposing wedge surfaces 21b, 21b of the pair of left and right pressing members 21a, 21a is such that the distance between the opposing wedge surfaces 21b, 21b expands downward. Has been.

  In a state where the upper mold 2 and the lower mold 1 are clamped or pressurized, the pair of pressing members 21a and 21a are brought closer to the lower inclined surface formed at the upper end of the left and right side surfaces of the upper mold 2. By moving horizontally, the wedge action by the lower inclined surfaces 2a, 2a and the wedge surfaces 21b, 21b formed at the upper ends of the left and right side surfaces of the upper mold 2 works. Here, the separation distance between the upper and lower molding surfaces of the upper and lower molds 2, 1 is determined by the movement stop position of the presser member 21 a in the left-right direction, and further upward movement of the upper mold 2 is prevented. In other words, since the distance between the upper mold 2 and the lower mold 1 is determined by the stop position of the holding member 21a, the distance between the upper mold 2 and the lower mold 1 can be arbitrarily adjusted by adjusting the stop position. can do. Once this stop position is determined, even if a large force is applied to the upper mold 2 from below, the upper mold 2 remains stationary and the stationary position is securely held, so that a molded product with high dimensional accuracy can be obtained. Can be obtained.

  With this position determined, the piston rod 5a, which is a pressing means, is projected into the cavity of the molding die 15, and a part of the outer peripheral surface of the prepreg 3 is pressed, so that the inside of the prepreg 3 is contained. A recessed portion 6 is formed on a part of the outer peripheral surface of the child 4. Thus, when the piston rod 5a presses a part of the outer peripheral surface of the core 4 via the prepreg 3, the volume of the core 4 is forced to be the volume of the piston rod 5a that has entered the volume of the granule 4a. Since it is in the added state, the internal pressure in the core 4 can be increased.

  As the internal pressure of the core 4 increases, the particles 4a accommodated in the packaging film 4b move in the front-rear and left-right directions due to slippage between the particles. Moreover, since the packaging film 4b wrapping each grain 4a is made of a material that can be extended, the packaging film 4b is deformed to allow movement of each grain 4a.

  In this way, by increasing the internal pressure of the core 4 and causing slippage between the particles 4a, the core 4 is deformed, and the gap between the core 4 and the prepreg 3 as shown in FIG. In addition, no gap is formed between the molding surface of the molding die 15 and the prepreg 3.

  That is, as the internal pressure of the core 4 increases, the particles 4a in the core 4 slip and deform the core 4. Then, the core 4 is deformed so that it is bent from the four corners on the inner surface of the prepreg 3 to a region along the inner surface of the vertical portion formed along the wall surface of the recess 1a of the lower mold 1 so that wrinkles and voids do not occur. Can be brought into close contact with the inner surface of the prepreg 3.

  When the prepreg 3 is placed in the molding die 15, even if a gap is formed between the prepreg 3 and the core 4 encapsulating the core 4, the gas constituting the gap Is subjected to an internal pressure due to the pressing of the core, and is released into the atmosphere through a small gap in the molding die 15 through the prepreg 3. The passage formed when air passes through the prepreg 3 is blocked by the molten resin of the prepreg 3 due to the pressure of the core 4 after the passage of air, and does not cause voids.

  In addition, when the prepreg 3 is placed in the molding die 15, there is a gap between the molding die 15 and the prepreg 3 at the corner of the molding die 15. Also, the prepreg 3 is deformed to the gap side by the pressing of the granule 4a moving inside the core 4. Then, the air forming the gap is pushed out from the molding die 15 into the atmosphere. The prepreg 3 moves to the space where the air is discharged, and the prepreg 3 is formed in a shape along the corner shape of the molding die 15. As a result, a molded product formed by pressure-molding the prepreg 3 becomes, for example, a high-quality molded product having corners that follow the shape of the mold.

As the internal pressure of the core 4 increases, the particles 4a slip and move in four directions between the particles. Moreover, since the packaging film 4b wrapping each grain 4a is made of a material that can be stretched, the packaging film 4b is expanded to allow movement of each grain 4a.

In this way, the internal pressure of the core 4 can be increased and slippage between the particles 4a can be caused, so that the core can be deformed. As shown in FIG. 2, the core 4 and the prepreg 3 and It is possible to prevent the formation of voids. Moreover, even if a gap is generated when the prepreg 3 is placed in the molding die 15, the deformation of the core 4 occurs at a portion where the pressure between the prepreg 3 and the prepreg 3 is low. When the mold is clamped with the lower mold 1, no gap is formed, and the thickness of the prepreg 3 can be maintained at a predetermined thickness.
Thus, the prepreg 3 can be pressure-molded into a shape having a predetermined thickness and a desired outer peripheral surface shape.

  In each drawing used in the description of the examples, the thickness of the packaging film 4b is shown in an exaggerated state in order to easily explain the packaging film 4b. Actually, the packaging film 4b is formed in a thin film shape, and its thickness is usually 1 mm or less.

  FIG. 3A shows a state in which the semi-molded product 10 a that has been subjected to pressure molding by the molding die 15 is taken out from the molding die 15. A recessed portion 6 is formed in a portion of the prepreg 3 pressed by the piston rod 5a.

As shown in FIG. 3 (b), when a discharge hole is formed in the bottom surface of the recessed portion 6, air flows between the particles 4a constituting the core 4 from the hole, and between the particles 4a. The combined state is broken. Then, the granule 4a in which the coupled state is broken can be discharged to the outside from the discharge hole formed in the recessed portion 6. And as shown in FIG.3 (c), the molded article 10 which has the hollow part 10b can be completed.
Here, when the packing material 4b is used to vacuum-pack the granules 4a, if the packaging film 4b is made of a material that has good peelability with respect to the molded product 10, the packaging film 4b is also molded. Can be removed from item 10. If the packaging film 4b is doubled, the packaging film 4b in contact with the granules 4a can be removed from the molded product 10.

  As described above, since pressure molding can be performed on the prepreg 3 in a state where there is no gap between the core 4 and the prepreg 3, the molded product 10 has a desired thickness with a desired thickness without bending or wrinkles. Products with quality and outer peripheral shape can be produced. Even if the internal pressure in the core 4 is low with the molding die closed, increasing the amount of protrusion of the piston rod 5a increases the internal pressure in the core 4, so that the molded product 10 Can be manufactured into a product having a desired thickness and a desired outer peripheral surface shape.

Next, the relationship between the change in internal pressure in the prepreg 3 and the movement stroke of the upper mold 2 and the extension stroke of the piston rod 5a will be described with reference to FIG. Before explaining FIG. 7, some assumptions will be described.
For example, it is assumed that the pressing surface for pressing the prepreg 3 with the upper mold 2 shown in FIG. 1 is rectangular, the lateral width W of the pressing surface is 100 mm, and the depth is 300 mm. At this time, the area of the pressing surface is 10 cm × 30 cm = 300 cm ² . Further, the diameter of the piston rod 5a is assumed to be φ38 mm, and the cylinder diameter of the cylinder 5 is assumed to be φ130 mm. The cylinder diameter of the hydraulic cylinder in the press device that presses the upper die 2 is set to φ252 mm.

At this time, assuming that the press pressure of the press device is 25 kg / cm ² , the load that can be applied to the upper die 2 at this time is: press pressure × area of hydraulic cylinder = 25 kg / cm ² × 25.2 cm × 25.2 cm × 3.14 / 4 = about 12.5 tons. Then, when the press pressure at the pressing device is 50 kg / cm ² which is twice the 25 kg / cm ^2, a load can be added to the upper mold 2 is pressed pressure described above at a 25 kg / cm ² You can add about 25ton which is double of 12.5ton.

When a load of 12.5 tons is applied to the upper mold 2, the stress per unit area when the prepreg 3 is pressed by the pressing surface of the upper mold 2 is the load / (pressed area of the upper mold 2) = 12,500 kg / 300 cm ² = approximately 42 kg / cm ² When a load of 25 tons, which is twice that of 12.5 tons, is applied to the upper die 2, the stress per unit area when pressing the prepreg 3 with the pressing surface of the upper die 2 is 12.5 tons. This is approximately 84 kg / cm ² , which is double that of the upper mold 2.

Also, assuming that the cylinder pressure in the φ5 mm cylinder 5 is 7 kg / cm ² , the pressing force that can be applied to the piston rod 5a at this time is: cylinder pressure × area of cylinder 5 = 7 kg / cm
cm ² × 13.0cm × 13.0cm × 3.14 / 4 = about 929Kg. The stress per unit area when the core 4 is pressed with the piston rod 5a is: pressing force / area of the piston rod 5a = 929 kg / 3.8 cm × 3.8 cm × 3.14 / 4 = about 82 kg / cm ² .
FIG. 7 will be described using the numerical values calculated above.

In FIG. 7, the vertical axis indicates stress (kg / cm ² ), and the horizontal axis indicates the stroke (cm) of the piston rod 5a. The figure is for explaining the relationship between stress and stroke in an easy-to-understand manner, and the scale and the like are shown reduced or exaggerated.
When the pressing device is operated, the upper die 2 comes into contact with the prepreg 3 at the point A and can press the prepreg 3. The broken line in the figure shows the case where the prepreg 3 is pressed only by the upper mold 2. The thick line shows the case where the pressing of the prepreg 3 by the upper mold 2 and the pressing of the core 4 by the piston rod 5a are used in combination according to the present invention. Note that the broken line and the thick line overlap each other until the stress increases from zero to the stress II.

First, the broken line will be described. When the stress is increased to the state II as shown by the broken line, the margins generated between the molding die 15 and the prepreg 3 and between the prepreg 3 and the core 4 are eliminated. Shall be able to. In this case, for example, if the pressing pressure in the pressing device is 25 kg / cm ² , the upper die 2 can be moved from the point A to the point B, and the stress can be further increased to the stress I. . The stress I at this time is 42 kg / cm ² which is obtained by the above calculation. Thereafter, by continuing the operation of the press device, the point C is reached as shown by the broken line in FIG. The stress at this time is the magnitude of the stress I.

Next, the thick line will be described. As described above, the piston rod is not operated until the upper die 2 reaches the point B, and a single pressurization is performed by the press device so that the press pressure in the press device is 25 kg / cm ² The mold 2 can be moved from the point A to the point B, and the stress can be increased to the stress II. The stress II at this time is 42 kg / cm ² obtained by the above calculation. When the upper mold 2 moves from the point A to the point B, the mold interval holding means 20 is operated to hold the position so that the upper mold 2 does not move away from the lower mold 1.

  From this holding state, the piston rod 5a is projected into the cavity. At this time, the piston rod 5a comes into contact with the core 4 to increase the internal pressure of the core 4. However, when the amount of the particles 4a constituting the core 4 is smaller than the volume of the package, While deforming the core 4, the piston rod 5 a is extended to the point C in order to increase the internal pressure to a desired internal pressure and return the core 4 to its original shape. The stress at this time remains II. In order to eliminate the gap generated between the molding die 15 and the prepreg 3 and between the prepreg 3 and the core 4, the piston rod 5a is moved to any point from the point C to the point E. By extending to the point, the internal pressure in the core 4 is increased to a desired internal pressure.

At this time, the internal pressure in the core 4 increases, and if the particles 4a flow in the core 4 to deform the core 4, the pressure between the core 4 and the prepreg 3 also increases. To do. As indicated by the thick line, the stress between the upper mold 2 and the prepreg 3 increases from the stress II state toward the stress I ′ state. Here, in the state of the stress II, when the particles 4a are not sufficiently distributed over the entire core 4, the piston rod 5a is further extended. At this time, the upper mold 2 receives a reaction force and tries to escape upward to open the mold.

In the present invention, as described above, the upper mold 2 is provided with the mold interval holding means 20. The upper mold 2 that tries to move in the opening direction of the mold is kept stationary by the mold interval holding means 20, and the upper mold 2 does not move in the opening direction. High-quality reinforced fiber plastic that has the desired shape and quality by positively exhausting the air that existed between the prepreg 3 and the mold cavity surface. A molded body is obtained. As a result, as determined by the above calculation, an appropriate stress of 82 kg / cm ² or more can be applied to the prepreg 3 via the core 4 by the pressing force from the piston rod 5a.

Thus, to obtain the pressing force of the 84 kg / cm ² and substantially equal to the stress 82 kg / cm ² of the stress caused when the upper die 2 is moved from the point A to the further point D from the piston rod 5a Can do. That is, by pressing a part of the core 4 with the piston rod 5a, for example, even if a load of 25 tons is not applied to the upper mold 2, a pressing force of 929 kg is applied after applying a load of 12.5 tons to the upper mold 2. The air gap can also be eliminated by pressing the core 4 with a piston rod 5a having

  The relationship between stress and stroke is affected by the volume change based on the extension length of the piston rod, so it is actually a complicated curve rather than a straight line. The relationship between stress and stroke will be explained in an easy-to-understand manner. Therefore, the graph is described using a straight line graph.

  Thus, in the present invention, even when the upper die 2 is not pressed with a large press device, the small press device and the cylinder 5 that presses the core 4 are used as in the case where the large press device is used. It is possible to eliminate gaps generated between the molding die 15 and the prepreg 3 and between the prepreg 3 and the core 4.

  In FIG. 7, the configuration in which a load is applied to the upper die 2 has been described. However, as shown in the above calculation, the pressing force by the piston rod 5a is substantially the same as the stress generated by the large press device. Can act on prepreg 3. Therefore, even when the piston rod 5a is applied to the core 4 after the molding die 15 is clamped, the stress can be increased to the state of stress I. That is, even when the piston rod 5a is operated after applying a load of 12.5 tons to the upper mold 2, it occurs between the molding die 15 and the prepreg 3 and between the prepreg 3 and the core 4. The voids that have been lost can be eliminated.

  Thus, although the high pressure as described above can be obtained by the protruding amount of the piston rod 5a, an attempt is made to further increase the pressure applied to the prepreg 3 during molding in order to make the overall thickness of the prepreg 3 thinner and uniform. If the upper die 2 is pushed upward beyond the limit of the pressing force of the pressing device as described above, the interval between the molding surface of the upper die 2 and the molding surface of the lower die 1 may be larger than the desired interval. There is.

In the present invention, the mold interval holding means 20 is provided on the upper die 2 in order to keep the vertical interval between the upper and lower dies 2 and 1 constant as described above.
When the pair of left and right holding members 21a, 21a of the mold interval holding means 20 are moved horizontally so as to approach the lower inclined surfaces 2a, 2a formed at the upper ends of the left and right side surfaces of the upper die 2, the upper die The wedge action by the lower inclined surfaces 2a, 2a and the wedge surfaces 21b, 21b formed at the upper end portions of the left and right side surfaces of 2 works. Here, the separation distance between the upper and lower molding surfaces of the upper and lower molds 2, 1 is determined by the movement stop position of the presser member 21 a in the left-right direction, and further upward movement of the upper mold 2 is prevented. That is, when the approaching movement of the presser members 21a and 21a is stopped, the upper mold 2 does not move further upward and remains in an immobile state, no matter how strong force is applied to the upper mold 2 from below. A molded product with high dimensional accuracy can be obtained.

  In the above description, the configuration in which the piston rod 5a is provided in the lower die 1 has been described. However, a configuration in which the piston rod 5a is provided in the upper die 2 can be employed. At this time, the piston rod 5a is provided on the upper mold 2 side, and the lower mold 1 is placed on a base or the like to restrict movement. The upper mold 2 is movable up and down as usual. Therefore, a configuration similar to that shown in FIG. 1 can be adopted as the configuration of the mold interval holding means 20 for preventing the upper mold 2 from lifting when the core 4 is pressed by the piston rod 5a.

In Example 1, a core 4 in which zirconia particles (mixed with a diameter of 1 mm and 3 mm) were vacuum packed with a nylon film as shown in FIG. 1 was produced. Carbon fiber reinforced epoxy resin prepreg 3 (TR3110 391IMU manufactured by Mitsubishi Rayon Co., Ltd.) is encapsulated in 5 plies, and the preform is formed at room temperature in the same shape as the inner peripheral surface of the mold 15 for molding. did. The preform is placed in the recess 1a formed in the lower mold 1 of the molding die 15 heated to 140 ° C. in advance, the upper mold 2 and the lower mold 1 are clamped, and then the mold interval holding means 20 Was operated to hold the position so that the upper mold 2 did not move away from the lower mold 1, and then a part of the outer peripheral surface of the core 4 was pressed at 82 kg / cm ² with the piston rod 5 a. After 10 minutes, the mold was opened and the molded product was taken out. A hollow for discharging is formed in the recessed portion 6 (FIG. 3 (a)) formed by pressing the piston rod, and the particles 4a are discharged to the outside through the hole for discharging (FIG. 3 (b)) to obtain a hollow molded product. (FIG. 3C). This molded product had high dimensional accuracy and was excellent in appearance without defects such as wrinkles on the outer surface.

A second embodiment according to the present invention will be described with reference to FIGS. 4 and 6B. In the first embodiment, an example in which a pair of presser members 21a and 21a having wedge surfaces 21b and 21b that are simply inclined is used as a presser member of the mold interval holding means 20 is described. A pair of pressing members 22a and 22a each having saw-toothed wedge surfaces 22b and 22b are used for the mold interval holding means 20. Further, in order to come into sliding contact with the sawtooth wedge surfaces 22b, 22b formed on the holding members 22a, 22a, sawtooth surfaces are formed at both ends of the upper die 2, respectively.
The other configuration has the same configuration as that of the first embodiment, and the same reference numerals as those used in the first embodiment are used for the same components, and the description of the members is omitted.

  As shown in FIG. 6 (B), the sawtooth wedge surfaces 22b, 22b formed on the pair of pressing members 22a, 22a are the horizontal planes 22c, 22c formed in the horizontal direction and the base ends of the horizontal planes 22c, 22c. The configuration including the lower inclined surfaces 22d and 22d continuously inclined downward is repeated. Then, as shown in FIG. 4, when the upper mold 2 descends toward the lower mold 1 and reaches a position where a preset pressure is applied to the prepreg 3, the mold interval holding means 20 is operated. When the pair of pressing members 22a, 22a are brought close to each other, the horizontal surface of the saw-toothed surface formed on the upper mold 2 and the horizontal surfaces 22c, 22c of the pressing members 22a, 22a are in surface contact. As a result, the upper mold 2 can be reliably prevented from moving upward.

  By operating the piston rod 5a from this state, the core 4 can be forcibly pressed and deformed by the piston rod 5a. That is, the core 4 can be deformed by pressing with the piston rod 5a, and a gap can be eliminated between the core 4 and the prepreg 3. Thus, the prepreg 3 can be pressure-molded so that a high-quality molded product having a desired thickness and a desired outer peripheral surface shape can be manufactured.

  In the second embodiment, as shown in FIG. 4, a pair of presser members 22a and 22a each having saw-toothed wedge surfaces 22b and 22b are used as the mold interval holding means 20, respectively. Molding was performed in the same manner. The mold is opened, the molded product is taken out, a hole for discharging is formed in the recessed portion 6 (FIG. 3A) formed by pressing the piston rod, and the granule 4a is discharged from the hole for discharging to the outside (FIG. 3). (B)), a hollow molded product was obtained (FIG. 3 (c)). This molded product had high dimensional accuracy and was excellent in appearance without defects such as wrinkles on the outer surface.

  The configuration of the third embodiment according to the present invention will be described with reference to FIGS. 5 and 6C. In the first embodiment, the configuration using the pair of pressing members 21a and 21a having the wedge surface 21b that is simply inclined as the mold interval holding means 20 has been described. However, in the third embodiment, the mold interval holding means 20 is described. A pair of pressing members 23a, 23a having wedge portions 23b, 23b having an upper inclined surface formed on the lower surface extending in the horizontal direction and vertical portions 23f, 23f extending vertically downward from the outer end portions thereof, The left and right ends of the upper mold 2 are formed in a surface shape in which the opposing surfaces of the pressing members 23a and 23a are in close contact with each other when the pair of pressing members 23a and 23a are brought into contact with the both ends.

In the third embodiment, the upper cavity surface of the upper mold 2 is not a mere flat surface but a protruding portion 8 is formed.
Other configurations are the same as those in the first embodiment, and the same components are denoted by the same reference numerals as those used in the first embodiment, and the description of the members is omitted.

  As shown in FIG. 6 (C), wedge portions 23b, 23b formed on the pair of left and right holding members 23a, 23a include upper inclined surfaces 23c, 23c extending laterally toward the upper mold 2, It consists of wedge portions 23b, 23b and vertical portions 23f, 23f having a shape with vertical surfaces 23d, 23e extending vertically from both ends of the inclined surfaces 23c, 23c. As shown in FIG. 5, the upper mold 2 is reliably moved upward by the surface contact between the inclined surfaces of the left and right ends of the upper mold 2 and the upper inclined surfaces 23c, 23c of the pressing members 23a, 23a. Can be blocked. Further, by sliding the pair of pressing members 23a, 23a in the direction of approaching / separating each other, the upper mold 2 is moved in the direction of approaching / separating from the lower mold 1, and the upper mold 2 is moved away from the lower mold 1. The interval can be adjusted.

  As shown in FIG. 5, when the upper die 2 is lowered toward the lower die 1 to press-mold the prepreg 3, the core 4 is forcibly pressed by the protruding portion 8 provided on the upper die 2. In this pressurized state, when the mold interval holding means 20 is operated to bring the pair of pressing members 23a, 23a closer, the inclined surface formed on the upper mold 2 and the upper inclined surfaces of the pressing members 23a, 23a By making surface contact with the surfaces 23c and 23c, it is possible to reliably prevent the upper mold 2 from moving upward and keep it in place.

  From this state, the piston rod 5a is operated to forcibly deform the core 4 between the protruding portion 8 and the piston rod 5a. As a result, as described above, the core 4 can be deformed, and the gap between the core 4 and the prepreg 3 can be eliminated. Thus, even in this embodiment, a high-quality hollow reinforced fiber plastic molded product having a desired wall thickness and a desired outer peripheral surface shape can be manufactured.

In the third embodiment, as shown in FIG. 5, the upper cavity surface of the upper mold 2 is not a mere flat surface but formed with a protruding portion 8, and the lower surface extending in the lateral direction is provided on the mold interval holding means 20. Using the pair of pressing members 23a and 23a having wedge portions 23b and 23b each having an upper inclined surface formed thereon and vertical portions 23f and 23f extending vertically downward from the outer end portions thereof, molding is performed in the same manner as in the first embodiment. It was. The mold is opened, the molded product is taken out, a hole for discharging is formed in the recessed portion 6 (FIG. 3A) formed by pressing the piston rod, and the granule 4a is discharged from the hole for discharging to the outside (FIG. 3). (B)), a hollow molded product was obtained (FIG. 3 (c)). This molded product had high dimensional accuracy and was excellent in appearance without defects such as wrinkles on the outer surface.

  Various configurations as shown in FIG. 6 can be adopted as the configuration of the pair of pressing members in the mold interval holding means 20. 6 (A) to 6 (C) have been described as the first to third embodiments described above, but a modification of the pressing member of the second embodiment shown in FIGS. 2 and 6 (B) This will be described with reference to FIG. In the pair of pressing members 24a and 24a shown in FIG. 6 (D), the wedge surfaces 24b and 24b are formed in a sawtooth shape, but the single teeth as shown in FIG. 6 (B) shown in the second embodiment. This is not a sawtooth shape but a double-toothed sawtooth shape. In this example, although not shown, wedge surfaces corresponding to the shapes of the wedge surfaces 24b, 24b are formed at the left and right ends of the upper mold 2.

  With this configuration, when the mold interval holding means 20 is operated, the wedge surfaces 24b, 24b of the pair of pressing members 24a, 24a are engaged with the wedge surfaces formed at both ends of the upper die 2, and the upper die 2 The movement in both the up and down directions is completely prevented.

  The present invention can be suitably applied in molding using a core.

DESCRIPTION OF SYMBOLS 1 Lower mold | type 1a Recessed part 2 Upper mold | type 2a Lower inclined surface 3 Prepreg 4 Core 4a Granule 4b Packaging film 5 Cylinder 5a Piston rod 6 Recessed part 8 Projection part 10 Molded article 10a Semi-molded article 10b Hollow part 15 Molding die 20 Die interval holding means 21a Holding member 21b Wedge surface 22a Holding member 22b Wedge surface 22c Horizontal surface 22d Lower inclined surface 23a Holding member 23b Wedge portion 23c Upper inclined surface
23d, 23e Vertical surface 23f Vertical portion 24a Holding member 24b Wedge surface 30 Molding die 31 Lower die 32 Upper die 33 Core 33a Powder 33b Packaging material 34, 35 Fiber reinforced thermoplastic resin (FRTP)
36 Prepreg 37 Vertical part
41a, 41b Mold for molding
42a, 42b Mating surface 43 Core 44 Extruder 45 Molten resin 46 Pressure unit

Claims (6)

Interposing a core capable of being deformed into a desired shape containing a large number of particles having fluidity in a flexible bag inside a prepreg in which fibers are impregnated with a resin ;
Arranging the prepreg containing the core between the upper mold and the lower mold of the molding die;
Holding with a mold interval holding means so that the interval between the upper mold and the lower mold does not widen at the time of mold clamping or pressure molding with the molding mold,
With a pressing means that protrudes and protrudes toward the cavity between the upper mold and the lower mold, the inner pressure in the core is increased and deformed by pressing a part of the outer peripheral surface of the core, and the pressing of the core A method for molding a fiber reinforced plastic, comprising improving adhesion between the prepreg and the mold and the core by deformation.   The mold interval holding means is disposed on the left and right side portions of the upper mold, and the mold interval holding means disposed on the left and right side portions of the upper mold is moved by a predetermined amount in a direction approaching each other. The method for molding a fiber reinforced plastic according to claim 1, comprising completely regulating upward movement of the upper mold.   3. The method for molding fiber-reinforced plastic according to claim 1, further comprising forming the left and right side surfaces of the upper mold and the contact surfaces of the mold interval holding means on a wedge-shaped sliding surface.   The pressing means includes a cylinder, and includes pressing a part of the outer peripheral surface of the core via the prepreg so as to sandwich the core by an expansion and contraction operation of a piston rod of the cylinder. Item 4. A method for molding a fiber-reinforced plastic according to any one of Items 1 to 3.   On the mold surface opposite to the side on which the pressing means is arranged with the prepreg in between, a fitting protrusion is provided that fits tightly into the cavity, and at the time of mold clamping or pressure molding by the molding mold And pressing the partial surface of the outer peripheral surface of the core so as to sandwich the core with the fitting protrusion and the pressing means of the molding die, respectively. 5. A method for molding a fiber-reinforced plastic according to any one of 4 above.   After compression molding, a hole communicating with the inside of the core is formed in a part of the outer peripheral surface of the core through the prepreg in the recess formed by the pressing means, and the particles are discharged from the hole. The molding method of the fiber reinforced plastic in any one of Claims 1-5 which consists of these.

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