JP2012071595A - Method of manufacturing composite molded object - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing a composite molded object by which a discontinuous fiber reinforced resin molding and a long fiber or continuous fiber reinforced resin molding and even a molding having a large surface area and thin thickness can be integrally molded in a desired shape precisely and easily at a low pressure without using a specific process while suppressing the deformation such as warpage.SOLUTION: In the method of manufacturing the composite molded object, a mold is arranged in a press end of a vertical press, a pre-molding comprising a reinforcing fiber and a thermoplastic resin is arranged in a cavity of the mold, a molten thermoplastic resin containing discontinuous reinforcing fiber is injected in the remaining space of the cavity, the cavity is pressed by the vertical press to reduce the cavity into a prescribed volume to press the pre-molding to the prescribed inner surface of the cavity while filling the discontinuous reinforcing fiber-containing thermoplastic resin in the cavity and the discontinuous reinforcing fiber-containing thermoplastic resin and the pre-molding are integrated to form the composite molded object.

Description

  The present invention relates to a method for producing a composite molded body, and more particularly to a method for efficiently and easily producing a composite molded body of a fiber reinforced thermoplastic resin having a desired form and mechanical properties.

  As a method for producing a fiber-reinforced thermoplastic resin molded article, injection molding is generally used. Usually, the thermoplastic molten resin is injected into a mold as a molding die in a state in which reinforcing fibers of short fibers are contained in the thermoplastic molten resin. The resin is cooled and solidified to obtain a molded product having a predetermined shape. However, in such normal injection-molded products, the thermoplastic resin is reinforced only with the reinforcing fibers of short fibers, and there is a limit to the reinforcing effect, so the use is limited from the viewpoint of mechanical properties such as rigidity. .

  In order to overcome such limitations, a method of reinforcing with a long fiber reinforced resin or a continuous fiber reinforced resin having higher strength and rigidity can be considered. However, in order to efficiently manufacture the entire molded product, it is desirable to integrally form the injection-molded short woven fiber reinforced resin and the long fiber or continuous fiber reinforced resin. However, it is difficult to easily integrally mold the molded product. there were. In other words, the normal injection molding method requires a considerably high molten resin supply pressure. Therefore, particularly when the molded product to be molded has a relatively large area and a thin wall thickness, the entire large area is short. A considerable high pressure is required to fill the fiber reinforced resin. In this state, the molding machine is required to have a very high clamping force, and at the same time, when trying to combine and integrate long fibers or continuous fiber reinforced resin, A preformed body made of a thermoplastic resin is likely to have a problem that the intended arrangement or the shape of the preformed body itself cannot be maintained. In addition, in order to perform molding with little residual distortion and small deformation such as warping, it is desirable to apply almost uniform pressure over the entire surface of the molded product, but high pressure is required as described above. It becomes difficult to lift large areas and apply uniform pressure. Furthermore, a normal injection molding machine is installed in a horizontal mold, and a mold is provided at the injection end of the injection machine. By using such an apparatus, the above-mentioned long fiber or continuous fiber reinforced resin preform is injection molded short. When it is going to be inserted in advance into the mold as an insert body for fiber reinforced resin reinforcement, special measures are required for the insertion method of the insert body, the gripping method to the mold, etc. There is a problem of complexity.

  Thus, it is not easy in the prior art to reinforce the injection-molded short fiber reinforced resin molded body by integral molding with long fibers or continuous fiber reinforced resin. Although a technique for integrating a thermoplastic resin sheet and a thermoplastic resin member in a die of a press molding apparatus is known (for example, Patent Documents 1 and 2), these conventional techniques are thermoplastic. It is intended only for resin molding, and is not capable of molding structures that require high mechanical properties (strength, rigidity), especially composite moldings of fiber reinforced thermoplastic resins. .

JP 2004-276257 A JP 2001-121561 A

  Therefore, in view of the above circumstances, the object of the present invention is to combine a special means with the conventional injection molding technique, and to form a discontinuous fiber reinforced resin molded body, particularly a short fiber reinforced resin molded body and a long fiber or continuous fiber reinforced resin. Even for molded products with a large area, and molded products with a small wall thickness, the molded body can be easily shaped at a low pressure without any special technique, and can be accurately deformed to a desired shape without warping. An object of the present invention is to provide a method for producing a composite molded body that can be integrally molded.

  In order to solve the above-mentioned problems, a method for producing a composite molded body according to the present invention includes a metal mold comprising an upper mold and a lower mold that are movable relative to the press end of a vertical press machine according to the operation of the press machine. A mold is placed, a preform made of reinforcing fibers and thermoplastic resin is placed in the cavity of the mold, and a molten thermoplastic resin containing discontinuous reinforcing fibers is injected into the remaining space of the cavity. The preform is pressed against a predetermined inner surface of the cavity while the cavity is filled with the molten thermoplastic resin containing discontinuous reinforcing fibers by reducing the cavity to a predetermined volume by pressing with the vertical press. The discontinuous reinforcing fiber-containing thermoplastic resin and the preformed body are integrated and molded into a composite molded body.

  In such a method for producing a composite molded body according to the present invention, in the step of supplying (injecting) the discontinuous reinforcing fiber-containing molten thermoplastic resin into the cavity, a space may remain in the cavity. Therefore, the supply pressure is much lower than the injection (supply) pressure in the conventional injection molding (for example, a low pressure of about 1/2 to 1/10 is sufficient). The discontinuous reinforcing fiber-containing molten thermoplastic resin supplied into the cavity is filled into the cavity by pressing with a vertical press, and the clamping pressure (molding pressure) at this time is also a counter pressure. Since the supply pressure into the cavity is low, it can be much lower than the clamping pressure in conventional injection molding (for example, a low pressure of about 1/3 to 1/6 is sufficient). In this way, it becomes possible to integrally mold the discontinuous reinforcing fiber-containing thermoplastic resin and the preform at a low pressure. As a result of the low-pressure molding, even a molded product having a large area, or even a molded product having a thin wall thickness, is easily filled with a molten thermoplastic resin containing discontinuous reinforcing fibers over the entire large area. Therefore, a desired integral molding can be performed. Also, the discontinuous reinforcing fiber-containing molten thermoplastic resin is filled into the cavity using the vertical press pressure by the vertical press, but the direction in which the resin is spread is the horizontal direction or the equivalent direction. Therefore, compared with the case of the vertical direction in the conventional injection molding or the equivalent direction, the resin easily spreads uniformly over the entire surface of the molded product, and it is easy to apply a uniform pressure over the entire cavity. Distribution is obtained and residual strain is reduced, thereby enabling molding with small deformation such as warpage. That is, a molded article having uniform physical properties and mechanical characteristics can be obtained in a desired form with high accuracy. As a result, discontinuous fiber reinforced resin moldings and preforms can be easily and accurately applied to molded products with large areas and even molded products with a small thickness without using a special technique. The reinforcing resin molded body for reinforcement using the body can be integrally molded, and the target composite molded body can be efficiently manufactured.

  In the method for producing a composite molded body according to the present invention, the reinforcing fiber of the preform is preferably a continuous fiber, but a long fiber having an average fiber length longer than that of the discontinuous reinforcing fiber may be used. In any case, it can be used to reinforce the discontinuous fiber reinforced resin molding. When long fibers are used as the reinforcing fibers of the preform, the weight average fiber length is preferably 1 to 50 mm. The preform is preferably flexible so as to be integrated along a predetermined shape in the mold cavity during molding. In addition to the case where the preform itself is flexible at room temperature, the preform can be integrated into the cavity after being adjusted to a flexible state by a preheating method.

  In particular, as a preform in a preferable form in the present invention, a sheet-shaped or tape-shaped preform in which the reinforcing fibers made of the continuous fibers or the long fibers are arranged in parallel in one direction, or a plurality of the preforms. A laminate may be mentioned. If the preform in such a form is used, the preform can be easily placed in a desired position in the cavity, and thus with respect to the final molded body.

  In the present invention, the discontinuous reinforcing fiber of the discontinuous reinforcing fiber-containing molten thermoplastic resin in the composite molded body after injection is preferably a short fiber as used in conventional injection molding. In particular, it is preferable that the fiber length contained in the discontinuous reinforcing fiber-containing molten thermoplastic resin in the composite molded body is a weight average fiber length of 0.4 mm to 3 mm. The fiber length of the melted thermoplastic resin containing discontinuous reinforcing fibers is easy to express high mechanical properties as a whole structure, and is compared in terms of matching of linear expansion coefficient with the preform. Longer fiber length is desirable. Specifically, the use of long fiber pellets for injection can be exemplified. In this case, it is particularly desirable that the fiber length after injection, that is, the fiber length contained in the discontinuous reinforcing fiber-containing molten thermoplastic resin is in the range of 0.4 mm to 3 mm in terms of weight average fiber length. When the weight average fiber length is less than 0.4 mm, the properties of the reinforcing fiber cannot be drawn out as in the case of using an ordinary compound pellet, and the molding shrinkage increases and the linear expansion coefficient also increases. Such difficulty can be suppressed when the weight average fiber length is 0.4 mm or more. When the weight average fiber length exceeds 3 mm, it is advantageous in terms of mechanical properties and the like, but the fiber length is too long for injection molding, resulting in problems in moldability such as a decrease in fluidity. The weight average fiber length of the reinforcing fibers contained in the pellets before injection is preferably in the range of about 2 to 15 mm, and preferably in the range of about 5 to 8 mm. As described above, it is desirable that the weight average fiber length is 0.4 mm to 3 mm when injected by a kneading machine.

  Further, in the present invention, the type of the reinforcing fiber is not particularly limited, and various reinforcing fibers such as carbon fiber, glass fiber, aramid fiber, or a hybrid reinforcing fiber including a plurality of these can be used. From the aspect of obtaining a composite molded body having excellent rigidity, at least one of the reinforcing fiber and the discontinuous reinforcing fiber of the preform preferably includes carbon fibers, and more preferably includes both carbon fibers.

  Further, as a connecting form of the vertical press machine and the mold, the press end can be connected to the upper mold of the mold, and the upper mold is moved up and down by the operation of the vertical press machine. It can be set to a form that is clamped and opened, but in this case, a preform is placed on the lower mold in the cavity, and the discontinuous reinforcing fiber is contained in the cavity from the cavity forming surface of the lower mold. By injecting the molten thermoplastic resin, a desired series of molding operations can be started with an extremely simple operation of simply placing the preform on the lower mold. In addition, it is not limited to arrange | positioning a (flexible) preforming body on the lower mold | type in the said cavity, It is also possible to arrange | position and shape | mold a preforming body to an upper mold | type with a certain method.

  The type of thermoplastic resin used in the present invention is not particularly limited. Examples of usable resins include polyamide (nylon 6, nylon 66, etc.), polyolefin (polyethylene, polypropylene, etc.), polyester (polyethylene terephthalate, polybutylene). Terephthalate, etc.), polycarbonate, polyamideimide, polyphenylene sulfide, polyphenylene oxide, polysulfone, polyethersulfone, polyetheretherketone, polyetherimide, polystyrene, ABS, liquid crystal polyester, and a copolymer of acrylonitrile and styrene. it can. A mixture of these may also be used. Moreover, what was copolymerized like the copolymer nylon of nylon 6 and nylon 66 may be used. Furthermore, depending on the required properties of the molded product to be obtained, flame retardants, weather resistance improvers, other antioxidants, heat stabilizers, UV absorbers, plasticizers, lubricants, colorants, compatibilizers, conductive fillers, etc. It can be added.

  Thus, according to the method for producing a composite molded body according to the present invention, the discontinuous fiber reinforced resin molded body and the long fiber or continuous fiber reinforced resin molded body can be integrally molded accurately without requiring any special device, Even for molded products with a large area, and even for molded products with a small wall thickness, the mechanical properties such as the target rigidity can be expressed uniformly, and the lightness that is the original characteristic is also provided. A composite molded body of a desired fiber-reinforced thermoplastic resin can be efficiently produced.

It is process drawing which shows the main steps of the manufacturing method of the composite molded object which concerns on one embodiment of this invention. It is process drawing which shows an example of the basic step of press molding using a saddle type press. It is explanatory drawing which shows the example of an integrated structure in the case of applying this invention to shaping | molding of a panel member. It is a top view of the cavity which shows the arrangement | positioning position of the preform in Example 1, 2 and a test piece cut-out position. FIG. 3 is a process diagram showing the main steps of a method for producing a composite molded body in Example 1. It is a figure which shows the result of having observed the cross section of the test piece of the composite molded object obtained in Example 1. FIG. FIG. 10 is a process diagram showing the main steps of a method for producing a composite molded body in Example 2.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 schematically shows the state of main steps in a method for producing a composite molded body according to an embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a mold composed of an upper mold 2 and a lower mold 3 that can be moved relative to each other. In this embodiment, the upper mold 2 is connected to a press end of a vertical press 4. Then, it is moved up and down according to the press operation of the press 4. The upper die 2 and the lower die 3 form a cavity 5 having a predetermined shape whose volume is changed according to the press operation of the press 4. A supply path 6 for injecting and supplying the material to be injected into the cavity 5 is provided in the lower mold 3. In this embodiment, the supply path 6 has an introduction end on the side surface side of the lower mold 3. The lower mold 3 is bent and extended from there, and is opened at the center of the upper surface of the lower mold 3 as the cavity 5 forming surface of the lower mold 3 as a supply end of the material to be injected.

  With the apparatus configuration up to this point, an apparatus for press molding using the vertical press 4 is configured. The basic operation will be described first with reference to FIG. In a state where the upper mold 2 is opened so that the volume of the cavity 5 is larger than the target volume of the molded product (a state where the mold is opened), the substance 7 (for example, molten resin) is injected into the cavity 5 through the supply path 6. And the fiber-containing molten resin) is started to be supplied, and the upper die 2 is lowered with respect to the lower die 3 by the press operation by the vertical press 4 while the volume of the cavity 5 is reduced. The injected material 7 that has been supplied or is still being supplied is pushed into the cavity 5 and the clamping is completed, and the injected material 7 is put into the cavity 5 that has been reduced to a predetermined volume. It is filled and press-molded into a molded product of a predetermined shape. This is one of the possible forming methods, but the forming device is not limited to such operation, and if the upper and lower operation control of the press can be freely set according to the shape of the mold and other requirements. Good.

  In press molding using such a vertical press machine 4, as described above, the supply pressure of the substance 7 to be injected is compared with the injection (supply) pressure in the conventional injection molding as compared with the normal injection molding method. A low pressure of about 1/2 to 1/10 is sufficient, and the mold clamping pressure P (molding pressure) can be a pressure of about 1/3 to 1/6 compared with the mold clamping pressure in the conventional injection molding. In addition, a uniform pressure is easily applied throughout the cavity 5, a uniform distribution of the resin is obtained, a residual strain is reduced, and a molding with a small deformation such as a warp becomes possible.

  In the present invention, the composite molded body is molded while taking full advantage of the advantages of press molding using the vertical press 4. Referring to FIG. 1 again, in the cavity 5 of the mold 1, in the illustrated example, on the upper surface which is the cavity forming surface of the lower mold 3, it is composed of continuous fibers or continuous fibers and thermoplastic resin. A sheet-shaped preform 10 is disposed. In this arrangement, for example, the edge of the preform 10 may be gripped between the lower edge of the upper mold 2 and an appropriate gripper 11. In the illustrated example, the gripping tool 11 is provided at the upper end of a telescopic guide member 12. In this state, the molten thermoplastic resin 13 containing discontinuous reinforcing fibers is supplied and injected into the cavity 5 through the supply path 6. The supply path 6 is opened at the center of the upper surface of the lower mold 3, and the preformed body 10 swells upward by the supply of the discontinuous reinforcing fiber-containing molten thermoplastic resin 13, and eventually the cavity forming surface of the upper mold 2. Along the inner surface. At the same time, the upper die 2 is lowered with respect to the lower die 3 by the operation of the vertical press 4, and at the same time, the molding pressure P (press pressure) is loaded into the cavity 5. When the upper die 2 is lowered, the guide member 12 is contracted, and the lowering operation is stopped when the predetermined cavity height is reached. However, it is desirable that a target molding pressure is applied throughout the cavity 5 at the descending end.

  By such a series of operations, the preformed body 10 is filled with the predetermined inner surface of the cavity 5 (in the illustrated example, in the illustrated example) while the discontinuous reinforcing fiber-containing molten thermoplastic resin 13 is filled into the cavity 5 reduced to a predetermined shape. Pressed against the inner surface of the upper mold 2, the discontinuous reinforcing fiber-containing thermoplastic resin 13 and the preformed body 10 are integrated into a composite molded body 14. After molding, the upper mold 2 may be opened by the operation of the vertical press 4 to take out the composite molded body 14.

  In this way, the target composite molded body 14 can be efficiently manufactured with an extremely simple operation and at a low pressure and a uniform pressure. Because it is molded at low pressure and uniform pressure, even if it has a relatively large area, even for molded products with thin wall thickness, desired mechanical properties such as rigidity are uniformly expressed. It is possible to easily perform the target composite molding.

  In the above-described example, the discontinuous reinforcing fiber-containing molten thermoplastic resin 13 supplying machine is not particularly shown, but the injection machine used in normal injection molding, the discontinuous reinforcing fiber and the molten thermoplastic resin are used. An extruder or the like that can be mixed together can be used as appropriate. In addition, although the mold attached to the press from the injection unit and the flow path to the cavity are also simplified in FIGS. 1 and 2, existing injection mold technology such as a hot runner can be freely applied. Is possible.

  In the illustrated example, the preform 10 is disposed so as to be pressed against the inner surface side of the upper mold 2, but may be disposed so as to be pressed against the inner surface side of the lower mold 3. Further, a preformed body 10 pressed against the inner surface side of the upper mold 2 and a preformed body 10 pressed against the inner surface side of the lower mold 3 are arranged, and a discontinuous reinforcing fiber-containing molten thermoplastic resin is disposed between the two preformed bodies 10. It is also possible to adopt a form in which 13 is injected and filled.

  As described above, the present invention is suitable for molding a composite molded body having a relatively large area, and further a composite molded body having a thin wall thickness.For example, a panel member having a composite structure (for example, main rigidity It is suitable for forming a panel member [for example, a panel member for automobiles] in which an interior material is provided on the inner surface side of a structural material and a exterior material on the outer surface side. FIG. 3 shows an example of an integrated configuration of the structural material 21, the interior material 22, and the exterior material 23 in such a panel member. In this case, the structural material 21 is a discontinuous reinforcing fiber-containing thermoplastic resin in the present invention, the interior material 22 or the exterior material 23 is a preformed body in the present invention, or vice versa. The integrated structure of can also be molded.

  As a preform, a tape-shaped unidirectional reinforcing fiber substrate (width) in which nylon fibers are impregnated with carbon fiber (Toray Industries, Inc., “Treca” (registered trademark) T700S-12K) aligned in one direction. : 50 mm, thickness: 0.3 mm). The thermoplastic resin containing discontinuous reinforcing fibers for injection is a nylon resin (TLP1060, manufactured by Toray Industries, Inc.) containing carbon fibers as reinforcing fibers inside, and the fiber length of the carbon fibers at the pellet stage Of about 7 mm and carbon fiber weight content Wf = about 30%.

[Example 1]
The upper mold and the lower mold provided in the vertical press machine (Amino Press, 1000t press machine) are opened, and the preforms are shown in FIGS. The preformed body 32 was arranged by two methods in which the attachment position of 32 was changed. As shown in FIGS. 5A, 5B, and 5C, with the cavity 31 open, the cylinder temperature in the injection apparatus is 270 ° C., and the mold temperature 80 of the mold including the upper mold 34 and the lower mold 35 is set. The above-described discontinuous reinforcing fiber-containing thermoplastic resin 36 is injected at 0 ° C., and after the injection is completed, the upper die 34 is pressed (clamped) with a molding machine at a molding pressure of 150 t. Then, a molded product having a thickness of 2 mm was formed.

  From the obtained molded product, the rectangular (40 mm × 25 mm) cutting positions shown in FIGS. 4 (A) and 4 (B) (41 and 43 are cut out at the portion where the preform 32 (UD tape) is arranged) The positions 42 and 44 are adjacent to the cut-out positions 41 and 43, and the cut-out positions at the portions where the preforms 32 are not arranged, and 45 are for injecting the discontinuous reinforcing fiber-containing thermoplastic resin 36 into the cavity 31. A test piece was cut out along each of the gate positions and subjected to a bending test (a bending test based on ISO178) to measure strength and elastic modulus. The results are shown in Table 1.

  The test piece of the portion where the unidirectional reinforcing fiber base material (preliminary body 32 made of the UD tape) is pasted on both sides has a strength of about 2.5 compared to the test piece of the portion without the unidirectional reinforcing fiber base material. The elastic modulus was strengthened by about 3 to about 3 times, and the elastic modulus was about 4 to 6 times. Moreover, when the cross section of the test piece 51 which affixed the unidirectional reinforcement fiber base material (UD tape) on both surfaces as shown in FIG. 6 was observed with the microscope, the preformed body 32 and the fiber reinforced resin 52 by which injection molding was carried out are carried out. Were confirmed to be well bonded at their interface. Moreover, as a molding pressure, it was able to mold well at a low pressure of 150 t.

[Example 2]
In the first embodiment, at the same position as shown in FIGS. 4A and 4B, as shown in FIGS. 7A, 7 </ b> B, and 7 </ b> C, on the lower mold 35 in the cavity 31. A molded product was molded in the same manner as in Example 1 except that the preformed body 32 was installed only (except for the zygomatic, single-sided application form), and a test piece was cut out.

  As a result of performing a bending test in the same manner as in Example 1, as compared with a test piece without a unidirectional reinforcing fiber base (preliminary body 32 made of the UD tape), a portion where the unidirectional reinforcing fiber base is pasted on one side The test piece was strengthened about twice as much in strength and about 2.5 times in elasticity. The results are shown in Table 2. Further, as a result of cross-sectional observation similar to that shown in FIG. 6, it was confirmed that the preform and the injection-molded fiber reinforced resin were well bonded at the interface between them.

[Comparative Example 1]
Using a conventional horizontal press machine, a preshaped object was placed in both molds (left and right opening) in the same manner as in Example 1 and molding was performed under the same molding conditions as in Example 1. Even when the molding pressure was increased to 350 t, the fiber reinforced resin could not be sufficiently injected.

  The method for producing a composite molded body according to the present invention can be applied to the production of any composite molded body using a fiber reinforced resin, and is particularly suitable for the production of a molded body having a large area and a small thickness. .

DESCRIPTION OF SYMBOLS 1 Mold 2 Upper mold 3 Lower mold 4 Vertical press machine 5 Cavity 6 Supply path 7 Injected material 10 Preliminary molded body 11 Gripping tool 12 Guide member 13 Discontinuous reinforcing fiber containing molten thermoplastic resin 14 Composite molded body 21 Structural material 22 Interior material 23 Exterior material 31 Cavity 32 Preliminary molded body 33 Vertical press machine 34 Upper mold 35 Lower mold 36 Discontinuously reinforced fiber-containing thermoplastic resins 41, 43 Cutting positions 42, 44 at the portion where the preformed body is arranged Cut-out position 45 at the portion where the preform is not arranged Injection gate position 51 Test piece 52 Injection-molded fiber reinforced resin

Claims (8)

  A mold composed of an upper mold and a lower mold which can be moved relative to each other according to the operation of the press machine is arranged at the press end of the vertical press machine, and the reinforcing fiber and the thermoplastic resin are placed in the mold cavity. By arranging a preformed body, injecting a molten thermoplastic resin containing discontinuous reinforcing fibers into the remaining space of the cavity, and reducing the cavity to a predetermined volume with a press by the vertical press The preform is pressed against a predetermined inner surface of the cavity while filling the discontinuous reinforcing fiber-containing molten thermoplastic resin into the cavity, and the discontinuous reinforcing fiber-containing thermoplastic resin and the preform are integrated to form a composite A method for producing a composite molded body, comprising molding into a molded body.   The method for producing a composite molded body according to claim 1, wherein the reinforcing fibers of the preform are made of continuous fibers.   The method for producing a composite molded body according to claim 1, wherein the reinforcing fibers of the preform are made of long fibers.   The method for producing a composite molded body according to claim 3, wherein the long fibers are made of fibers having a weight average fiber length of 1 to 50 mm.   The preform according to any one of claims 1 to 4, wherein the preform comprises a sheet-like or tape-like preform in which reinforcing fibers are arranged in parallel in one direction, or a laminate of a plurality of the preforms. The manufacturing method of the composite molded object of description.   The composite molded body according to any one of claims 1 to 5, wherein the discontinuous reinforcing fiber-containing molten thermoplastic resin in the composite molded body contains a fiber length of 0.4 to 3 mm in weight average fiber length. Method.   The manufacturing method of the composite molded object in any one of Claims 1-6 in which at least one of the reinforced fiber of the said preforming body and the said discontinuous reinforced fiber contains carbon fiber.   A press end of the vertical press is connected to the upper die, the preform is arranged on the lower die in the cavity, and the discontinuous reinforcing fiber-containing melt is inserted into the cavity from the cavity forming surface of the lower die. The method for producing a composite molded body according to any one of claims 1 to 7, wherein a thermoplastic resin is injected.

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