JP2009101553A - Apparatus and method for manufacturing hollow molding - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus for manufacturing a hollow molding by which the hollow molding can be suitably manufactured without reducing productivity by suppressing damage due to steam generated during heating molding. <P>SOLUTION: The manufacturing apparatus of the hollow molding has a molding mold 2 which has a cavity 20 inside, a core material 3 which is inserted in the cavity 20, an opening/closing means 4 which opens and closes a gate 21 of the molding mold 2 and a molding material supply means 5 which supplies a molding raw material in the cavity 20 through the gate 21. A top end part 30 of the core material 3 and/or a cross section of a gate 22 of the core material 3 in the molding mold 2 have a shape which gradually narrows towards an insertion direction of the core material 3. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a hollow molded body, in particular, a manufacturing apparatus and a manufacturing method for a hollow molded body suitable for a casting mold or structure (hereinafter, also referred to as a mold).

  When casting a hollow casting in a general casting manufacturing method, a core is formed with foundry sand, the core is set in a main mold, molten metal is cast, and the mold is opened after cooling. After demolding the casting, the core is disintegrated and removed to obtain the desired casting.

  By the way, since the core is shaped by curing casting sand obtained by adding a binder to normal sand, there is a problem that a decomposition gas such as amine is generated during casting. Moreover, since it was fragile, when it set to the main type | mold, or when kelen was mounted | worn, the point which was easy to break at the time of pouring was a subject. Furthermore, when sand is reused, a regeneration process is required. However, there is a problem that waste such as dust is generated during the regeneration process.

  The applicant has proposed the technique described in Patent Document 1 below. In this technique, a mold or the like used for casting is formed of a molded body containing organic fibers, inorganic fibers, and a thermosetting resin. The molded body by this technique is thin and lightweight and excellent in workability as compared with a mold using conventional casting sand. Further, there is no problem that the above-mentioned waste is generated. However, since this molded body is manufactured by papermaking, a technique capable of manufacturing the molded body by a simpler method has been desired. Moreover, in the manufacture by papermaking, it has been difficult to form a complicated shape in which the thickness of the molded body varies greatly.

  On the other hand, Patent Documents 2 and 3 propose techniques for forming a molded body by injection molding a raw material. However, these techniques are suitable from the viewpoint of molding a complicated shape in which the thickness of the molded body changes greatly, but there is no disclosure about the manufacturing technology of the hollow molded body, and it is due to the generation of steam caused by the raw material. The breakage of the hollow molded body could not be suppressed.

JP 2004-181472 A JP-A-11-280000 JP 2003-71897 A

  Accordingly, the present invention has been made in view of the above problems, and a hollow molded body that can be suitably manufactured without reducing the productivity by suppressing damage caused by steam generated during the heat molding. It aims at providing the manufacturing apparatus and manufacturing method of a molded object.

  The present invention provides a molding die having a cavity therein, a core material inserted into the cavity, an opening / closing means for opening and closing the gate of the molding die, and a molding raw material for supplying the molding raw material into the cavity through the gate. An apparatus for manufacturing a hollow molded body comprising a supply means, wherein a cross-section of a distal end portion of the core material and / or an entrance / exit of the core material in the molding die is gradually narrowed in an insertion direction of the core material. The object is achieved by providing an apparatus for producing a hollow molded body having a form.

  Further, the present invention uses the above-described hollow molded body manufacturing apparatus of the present invention, and press-fills the molding raw material into the cavity through the gate with the core material inserted into the cavity of the mold. Then, while the gate is closed and the forming raw material is heat-molded, the core material is pulled out from the mold, and steam is evacuated from the gap between the core material and the inlet / outlet, and then the forming raw material is The object is achieved by providing a method for producing a hollow molded body that is subsequently heated and dried.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing apparatus and manufacturing method of a hollow molded object which can suppress the damage by the vapor | steam which generate | occur | produces at the time of the thermoforming, and can be manufactured suitably are provided.

  Hereinafter, the present invention will be described based on preferred embodiments thereof.

  First, the manufacturing apparatus of the hollow molded object of this invention is demonstrated, referring drawings based on the preferable embodiment.

  1 to 5 are schematic views of an embodiment of a hollow molded body manufacturing apparatus (hereinafter also simply referred to as a manufacturing apparatus) according to the present invention. In these drawings, reference numeral 1 is a manufacturing apparatus, 10 is a hollow molded body (hereinafter also simply referred to as a molded body), and 100 is a raw material for molding (prepared by adding a dispersion medium to a composition for manufacturing a molded body described later). Raw material).

  As shown in FIG. 1, the manufacturing apparatus 1 includes a molding die 2 having a cavity 20 therein, a core 3 inserted into the cavity 20 of the molding die 2, and a gate of the molding die 2 (hereinafter also referred to as a gate hole). 21) the opening / closing means 4 and the molding raw material supply means 5 for supplying the molding raw material into the cavity 20.

  The mold 2 is composed of a pair of split molds 2A and 2B. By combining these split molds, the mold 2 has a cavity 20 formed therein, and a gate hole (gate) 21 leading to the cavity 20 and an entrance / exit 22 of the core material 3 are formed. The formation surface of the cavity 20 formed by the inner surface of each split mold corresponds to the outer shape of the molded body 10. In the split mold 2 </ b> B, a forming raw material inlet 23 leading to the gate hole 21 is formed. The split mold is made of a metal such as an aluminum alloy or stainless steel. The mold 2 is attached to a platen of mold clamping means (not shown), and is opened and closed in the vertical direction. Each split mold is heated to a predetermined temperature by a heating means (not shown).

  The cross-section of the distal end portion 30 of the core material 3 has a form that gradually narrows in the insertion direction of the core material 3. The ridge line 31 of the tip 30 may be a curve or a straight line, but in the present embodiment, the core material 3 has a rod-like form having a taper portion 32 (the ridge line 31 is a straight line) at the tip 30. ing. The outer surface of the core material 3 corresponds to the shape of the inner surface of the hollow portion of the molded body 10. The core material 3 is driven back and forth (in the left-right direction in FIG. 1) by driving means (not shown), and is put into and out of the cavity 20 through the entrance / exit 22 of the mold 2.

  The gate opening / closing means 4 includes a gate pin 40 that slides in the gate hole 21. The gate pin 40 is driven back and forth (left and right direction in FIG. 1) by a driving means (not shown), and the tip portion slides inside the gate hole 21 of the mold 2.

  The molding material supply means 5 is constituted by a so-called fluid pressure cylinder / piston unit. The molding material supply means 5 includes a cylinder 50 in which the molding material is accommodated, a piston 51 that slides in the cylinder 50, and a nozzle 52 that discharges the molding material pressed by the piston 51. The molding material supply means is configured such that when the nozzle 52 is inserted into the molding material inlet 23 and a fluid such as pressurized air is supplied into the cylinder 50, the piston 51 rises, The forming material 100 is supplied to the gate hole 21 through the nozzle 52.

  The manufacturing apparatus 1 includes control means (not shown) including a sequencer that operates the mold 2, the core material 3, the gate opening / closing means 4, and the forming raw material supply means 5 according to a procedure described later.

  Next, referring to FIGS. 1 to 5, based on an embodiment in which the manufacturing method of the hollow molded body of the present invention is applied to the manufacturing method of a hollow core used for casting using the manufacturing apparatus 1. While explaining.

  In the method for producing a hollow molded body of the present embodiment, first, a forming raw material is prepared. In the preparation of the forming raw material, inorganic powder is a main component, and inorganic fibers, a thermosetting resin, and a water-soluble binder are mixed in advance by a dry method. When the thermally expandable particles are included, they are included at the time of this dry mixing. And these mixtures (composition for molded object manufacture) are disperse | distributed to a dispersion medium, and it knead | mixes with a kneader, and prepares a shaping | molding raw material in dough shape. Here, having inorganic powder as a main component means that the inorganic powder is the largest in mass ratio among all components contained in the molded body.

  Here, preparing the forming raw material in a dough shape means that the powder, the fiber composition, and the dispersion medium are kneaded gently, and the powder, the fiber composition, and the dispersion medium are easily separated while having fluidity. It means to prepare in the state without.

  Examples of the dispersion medium include water, a solvent such as ethanol and methanol, and an aqueous dispersion medium such as a mixed system thereof. Water is particularly preferable from the viewpoints of molding stability, stability of the quality of the molded body, cost, ease of handling, and the like.

  Examples of the inorganic powder include graphite (for example, scaly graphite), obsidian, mica, talc, mullite, silica, magnesia, and the like. One or more inorganic powders can be selected and used. From the viewpoint of moldability and cost, it is preferable to use graphite.

  The inorganic fiber mainly forms a skeleton of a molded body, and maintains its shape without being burned by the heat of molten metal during casting, for example. Examples of the inorganic fibers include artificial mineral fibers such as carbon fibers and rock wool, ceramic fibers, and natural mineral fibers. One or two or more inorganic fibers can be selected and used. Among these, it is preferable to use pitch-based or polyacrylonitrile (PAN) -based carbon fibers having high strength even at high temperatures from the viewpoint of effectively suppressing shrinkage associated with carbonization of the thermosetting resin.

  The inorganic fiber preferably has an average fiber length of 0.5 to 15 mm, particularly 1 to 8 mm, from the viewpoint of moldability and uniformity of a mold or the like.

  The thermosetting resin is necessary for maintaining the normal temperature strength and hot strength of the molded body, improving the surface properties of the molded body, and improving the surface roughness of the casting when the molded body is used as a mold. Is an essential ingredient. Examples of the thermosetting resin include a phenol resin, an epoxy resin, and a furan resin. Among these, in particular, there is little generation of combustible gas, there is a combustion suppressing effect, the residual carbon ratio after pyrolysis (carbonization) is as high as 25% or more, and a carbonized film is formed when the molded body is used as a mold. It is preferable to use a phenol resin from the viewpoint that a good casting surface can be obtained. As the phenol resin, a novolak phenol resin that requires a curing agent or a resol type phenol resin that does not require a curing agent is used. The said thermosetting resin can select and use 1 type, or 2 or more types.

  Examples of the water-soluble binder include thickening polysaccharides, polyvinyl alcohol, and polyethylene glycol. Examples of the polysaccharide include gum agents such as xanthan gum, tamarind gum, gellan gum, guar gum, locust bean gum and tara gum, cellulose derivatives such as carboxymethyl cellulose and hydroxyethyl cellulose, carrageenan, pullulan, pectin, alginic acid and agar. Among these polysaccharides, non-natural products such as cellulose derivatives and chemically modified products such as carboxymethyl cellulose are used in a small amount of the water-soluble binder in the composition for producing molded products, rather than natural products such as agar. It is favorable from the viewpoint of exhibiting performance.

  In the composition for manufacturing a molded body, the mixing ratio (mass ratio) of each component is based on the total mass of the inorganic powder, the inorganic fiber, the thermosetting resin, and the water-soluble binder (solid content). Inorganic powder / inorganic fiber / thermosetting resin / water-soluble binder (solid content) = 40 to 90/1 to 20/1 to 30/1 to 10 (mass ratio) is preferable, and 50 to 85/2 16/2 to 25/1 to 5 (mass ratio) is more preferable, and 50 to 85/2 to 16/2 to 20/1 to 5 (mass ratio) is more preferable. (However, the sum of the mass ratios is 100.)

  When the blending ratio of the inorganic powder is within the above range, the shape retention at the time of casting and the surface property of the molded product are good, and the releasability after molding is also suitable. When the blending ratio of the inorganic fibers is within the above range, moldability and shape retention during casting are good. When the blending ratio of the thermosetting resin is within the above range, moldability, shape retention after casting, and surface smoothness are good. When the blending ratio of the water-soluble binder is within the above range, when the molding raw material is filled in the molding die, the molding raw material can be filled with good fluidity, and the moldability of the molded body is improved. .

  When heat-expandable particles are included in the forming raw material, the heat-expandable particles are preferably microcapsules in which an expansion agent that expands by vaporization is encapsulated in the shell wall of a thermoplastic resin. When the microcapsule is heated at 80 to 200 ° C., the diameter preferably expands to 3 to 5 times, the volume preferably expands to 50 to 100 times, and the average particle diameter before expansion is preferably 5 to 80 μm, more preferably Particles of 20-50 μm are preferred. When the expansion of the thermally expandable particles is within such a range, the effect of addition can be sufficiently obtained while suppressing the adverse effect on the molding accuracy due to the expansion. The thermally expandable particles preferably have an average diameter before expansion of 5 to 80 μm, more preferably 20 to 50 μm.

  Examples of the thermoplastic resin constituting the shell wall of the microcapsule include polystyrene, polyethylene, polypropylene, polyacrylonitrile, acrylonitrile-vinylidene chloride copolymer, ethylene-vinyl acetate copolymer, or combinations thereof. Examples of the expanding agent contained in the shell wall include low-boiling organic solvents such as propane, butane, pentane, isobutane, and petroleum ether.

  The thermally expandable particles preferably include 0.5 to 10% (% by mass) with respect to the total mass of the inorganic powder, the inorganic fiber, the thermosetting resin, and the water-soluble binder. It is more preferable to contain 1 to 5% (mass%). When the thermally expandable particles are contained in such a range, the molding raw material is filled in the details of the mold by expansion, and the shape of the mold can be faithfully transferred, and the effect of addition can be sufficiently obtained. In the case of the above range, since a large amount of thermally expandable particles is not included, overexpansion can be prevented and no extra cooling time is required, so that high productivity can be maintained.

  In addition to the components described above, other components such as a colorant, a release agent, and colloidal silica can be added to the molded body of the present embodiment at an appropriate ratio. Moreover, the molded object of this embodiment can contain a tree fiber in the range which does not exert a bad influence on the effect. Examples of the organic fiber include paper fiber (pulp fiber), fibrillated synthetic fiber, and regenerated fiber (for example, rayon fiber). One or two or more organic fibers can be selected and used. Paper fiber is preferable from the viewpoints of moldability, strength after drying, and cost.

  Next, as shown in FIG. 1, the mold 2 is clamped and the core material 3 and the gate pin 40 are set. The temperature of the molding die at this time is preferably 120 to 250 ° C. in consideration of evaporation of the dispersion medium, curing rate of the thermosetting resin, expansion rate of the thermally expandable particles, burning of the forming raw material, and the like. Then, as shown in FIG. 2, the molding material 100 is filled into the molding die 2 while being pressurized from the molding material inlet 23 by raising the piston 51 of the molding material supply means 5. When air is used for the pressurized fluid of the forming raw material supply means 5, the air pressure is preferably 0.5 to 3 MPa. Further, the filling pressure of the forming raw material into the mold 2 changes while filling, but the maximum filling pressure is equal to the air pressure.

  Next, as shown in FIG. 3, the gate pin 40 is moved forward by the driving means so that the cavity 20 is sealed.

  After the heating for a predetermined time, the core material 3 is once retracted by the driving means during the molding in order to remove the vapor from the inside of the molded body 10, and as shown in FIG. The drawing of the core material 3 is stopped. Then, steam is vented to prevent damage to the molded body 10 due to rapid deaeration.

  The steam is generated because the forming raw material contains the dispersion medium. Even if a gas other than the dispersion medium vapor is generated, the steam can be discharged from the mold by performing the steam removal. As a gas other than the vapor of the dispersion medium, when phenol resin is used as the thermosetting resin, formalin gas, free phenol gas, etc. are generated, and further, the thermally expandable particles are used for the particles. The hydrocarbon gas inside the microcapsule is generated.

  After performing necessary steam removal, the molded body is dried by continuing heating for a predetermined time. Then, as shown in FIG. 5, the gate pin 40 is retracted, the mold 2 is opened, and the molded body 10 is taken out. The molded body 10 is post-cooled and subjected to post-processing such as trimming, chemical application, and reheating as necessary after completion of cooling.

  In the manufacturing method of the hollow molded body of the present embodiment, the core material 3 is pulled out after the molded body 10 is heat-molded, and steam is extracted from the inside of the molded body 10 through the gap between the inner periphery of the entrance / exit 22 and the tapered portion 32. Thereafter, since the molded body 10 is continuously heated and dried, damage to the molded body due to vapor explosion or the like can be suppressed and the molded body 10 can be manufactured at high speed.

  FIG. 6 is a schematic view of a molded body manufactured in this manner. The front end 101 of the molded body 10 is closed and the rear end 102 is open. Moreover, the molded object 10 has a part where an outer diameter becomes thick, and in this embodiment, the outer diameter of the rear-end part 102 is formed thicker than another part.

  Moreover, when the molded object 10 is manufactured from the shaping | molding raw material containing water, 5% or less is preferable and the moisture content before using of this molded object (before using for casting) is preferable, and 2% or less is more preferable. . The lower the moisture content, the lower the amount of gas generated due to thermal decomposition (carbonization) of the thermosetting resin during casting.

  Further, the molded body 10 is mainly composed of inorganic powder, contains inorganic fibers, a thermosetting resin, and a water-soluble binder, is lightweight, has high normal temperature strength, and uses kelen or the like. Excellent handling when used as a child. Moreover, since there is little generation | occurrence | production of the gas accompanying thermal decomposition at the time of use, the bad influence on an environment can be restrained low. In addition, since the dimensional accuracy is high and the hot strength is high, a highly accurate casting can be stably manufactured. In particular, when the thermally expandable particles are included, since the molded body has high molding accuracy over the details, a casting with higher accuracy can be manufactured. Also, the inside is hollow, and the gas generated during casting can be efficiently discharged from the hollow part to the outside, and it is lighter and can be easily made fine by blasting after use. Also excellent in handling.

  The present invention is not limited to the above-described embodiment, and can be modified as appropriate without departing from the spirit of the present invention.

  In the above-described embodiment, the cross section of the tip of the core material is gradually narrowed toward the insertion direction of the core material (the taper portion is provided at the tip), but the cross section of the tip of the core material is used. Instead of the shape, the cross-section of the core material entrance and exit may be gradually narrowed in the direction of insertion of the core material, and both the cross-section of the tip of the core material and the cross-section of the core material It can also be made into the form which narrows gradually toward the insertion direction of a core material.

  In addition to the core used for casting as in the above-described embodiment, the hollow molded body manufacturing apparatus and manufacturing method of the present invention include a mold (main mold), a runner, a hot water stop, a receiving port, a gate, a gate bottom, It is suitable for the use of structures such as cough, degassing, frying, and hot water, and other incidental structures. Further, it can be applied to uses other than the casting field requiring heat resistance, and high molding accuracy can be achieved over the details of the shape according to the use.

Further, the manufacturing apparatus and the manufacturing method of the present invention are the same as in the embodiment described above, in which the inorganic powder, the inorganic fiber, the thermosetting resin, the water-soluble binder (solid content), and the thermally expandable particles. Although it is suitable for the manufacture of a hollow molded body using a molding raw material containing, it can also be applied to the manufacture of a hollow molded body using other molding raw materials.
For example, the present invention can also be applied to the production of a molded body using a mixture of organic fiber and starch kneaded with water as a dispersion medium.

  Hereinafter, the present invention will be described more specifically with reference to examples. In addition, this invention is not restrict | limited to a present Example at all.

  As in the following Examples and Comparative Examples 1 to 3, a molded body was molded from a molding raw material having the following composition using a molding die having a cavity with the following dimensions and shape, and whether or not molding was possible was obtained. The appearance of the molded body was evaluated, and the results are shown in Table 1.

〔Example〕
<Preparation of molding composition and molding raw material>
After preparing the composition for manufacturing a molded body having a blending ratio (mass ratio) of inorganic powder, inorganic fiber, thermosetting resin, water-soluble binder and thermally expandable particles as follows, this composition for manufacturing the molded body Water as a dispersion medium was added to the product to prepare a forming raw material having a moisture content of about 45% (water was 45% by mass with respect to the total mass of inorganic powder, inorganic fiber, thermosetting resin and water-soluble binder).

[Compositional components of the composition for forming a molded body]
Inorganic powder: Graphite Inorganic fiber: PAN carbon fiber (manufactured by Toray Industries, Inc., trade name “Treka chop”), fiber length: 3 mm, shrinkage: 0.1%)
Thermosetting resin: Phenolic resin ("S890" manufactured by Air Water Bell Pearl Co., Ltd.)
Water-soluble binder: Carboxymethyl cellulose (Serogen HE-1500F manufactured by Daiichi Kogyo Seiyaku Co., Ltd.)
Thermally expandable particles: Thermally expandable microcapsules (manufactured by Matsumoto Yushi Seiyaku Co., Ltd., trade name “Matsumoto Microsphere F-105D”)
Component mass blending ratio (%): inorganic powder / inorganic fiber / thermosetting resin / water-soluble binder / heat-expandable particles = 82/4/10/2/2
Dispersion medium: water

[Molding conditions of molded body]
Air pressure of forming raw material supply means: 1 MPa
Mold temperature: 200 ° C
Heating time: 150 seconds Steam venting time: 10 seconds Heating and drying time: 20 seconds

[Dimensional shape of the molded body]
As shown in FIG. 6, a hollow rod-shaped molded body having a closed tip was obtained.
Outer diameter = 14 mm (excluding the rear end portion 102), total length = 300 mm, hollow portion diameter = 8 mm, hollow portion length = 290 mm
[Molding status]
As a result of molding according to the molding conditions described above, as shown in Table 1, a desired molded body having a good appearance of the molded body could be obtained.

[Comparative Example 1]
Molded bodies were produced by changing the molding conditions using the same molding raw materials as in the examples. Specifically, the molding was performed under the condition that the core material was not retracted and the steam venting operation was not performed.

[Molding conditions of molded body]
Heating time: 180 seconds Steam venting time: 0 seconds Drying time: 0 seconds [Situation of molding]
After the predetermined heating time, when the mold was opened, the molded body exploded due to the pressure of the internal steam, and the molded body could not be obtained.

[Comparative Example 2]
Molded bodies were produced by changing the molding conditions using the same molding raw materials as in the examples. Specifically, after the same heating time as in the example, the core material 3 was pulled out at a stretch without stopping the drawing where the tapered portion 32 hits the entrance 22.

[Molding conditions of molded body]
Heating time: 150 seconds [Situation of molding]
When the core material was pulled out after the above-mentioned predetermined heating time, the molding raw material in the molding was ejected from the inlet / outlet 22 as the internal steam was released, and a molded body could not be obtained.

[Comparative Example 3]
Molded bodies were produced by changing the molding conditions using the same molding raw materials as in the examples. Specifically, the molding was carried out by extending the heating time under the condition that the core material was not retracted and the steam venting operation was not performed.

[Molding conditions of molded body]
Heating time: 600 seconds [Situation of molding]
As a result of molding according to the molding conditions described above, as shown in Table 1, a desired molded article having a good appearance could be obtained. However, the heating time required 4 times as long as the Example.

<Result>
As shown in Table 1, in Comparative Examples 1 and 2, a desired molded product could not be obtained. In addition, a molded body can be obtained by significantly increasing the heating time as in Comparative Example 3, but the productivity is significantly reduced, and the effectiveness of the apparatus and method of the present invention is confirmed. .

  The method for producing a molded article of the present invention is particularly suitable for producing the molded article when the molded article is used as a mold or the like, and in addition to that, for producing various molded articles such as containers, tools and parts. It can also be applied.

It is a fragmentary sectional view which shows typically one Embodiment of the manufacturing apparatus of the hollow molded object of this invention. It is a fragmentary sectional view which shows typically the supply process of the shaping | molding raw material in one Embodiment of the manufacturing method of the hollow molded object of this invention using the manufacturing apparatus. It is a fragmentary sectional view which shows typically the formation process in one Embodiment of the manufacturing method of the hollow molded object of this invention using the manufacturing apparatus. It is a fragmentary sectional view which shows typically the heat drying process in one Embodiment of the manufacturing method of the hollow molded object of this invention using the manufacturing apparatus. It is a fragmentary sectional view which shows typically the demolding process in one Embodiment of the manufacturing method of the hollow molded object of this invention using the manufacturing apparatus. It is a half sectional view showing one embodiment of the hollow fabrication object manufactured by the manufacturing method of the hollow fabrication object of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Manufacturing apparatus of molded object 2 Mold 2A, 2B Split mold 20 Cavity 21 Gate hole (gate)
22 Entrance / Exit 3 Core Material 30 Tip Part 31 Ridge Line 32 Tapered Part 4 Gate Opening / Closing Means 40 Gate Pin 5 Molding Raw Material Supply Means 50 Cylinder 51 Piston 52 Nozzle 10 Molded Body

Claims (3)

A molding die having a cavity inside; a core material inserted into the cavity; an opening / closing means for opening and closing a gate of the molding die; and a molding raw material supply means for supplying a molding raw material into the cavity through the gate. An apparatus for manufacturing a hollow molded body, comprising:
An apparatus for producing a hollow molded body, wherein a tip end portion of the core material and / or a cross section of an entrance / exit of the core material in the molding die gradually narrows in an insertion direction of the core material.   The manufacturing apparatus of the hollow molded object of Claim 1 which has a taper part in the front-end | tip part of the said core material. Using the hollow molded body manufacturing apparatus according to claim 1,
While the core material is inserted into the cavity of the molding die, the molding material is pressurized and filled into the cavity through the gate, and the molding material is heated and molded while the gate is closed. A method for producing a hollow molded body in which a core material is pulled out from the mold and subjected to vapor removal from a gap between the core material and the inlet / outlet, and then the molding material is continuously heated and dried.

Images