JP2006088363A - Method and apparatus for molding thermoplastic resin sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a molded product having a good appearance shape by preventing a resin sheet from lowering in temperature at the time of shaping, and to enhance the production yield of the molded product. <P>SOLUTION: This molding apparatus is constituted of upper and lower molds provided in a mutually opposed state, the heater parts provided to the almost central parts of the upper and lower molds and a sheet holding part for holding an upper sheet in the upward direction of the heater part so as to make the same almost parallel to the upper heating surface of the heater part in the upper direction of the heater part and holding the lower sheet so as to make the same almost parallel to the under heating surface of the heater part in the downward direction of the heater part. The first space formed between the upper mold and the upper resin sheet, the second space formed between the upper resin sheet and the lower resin sheet and the third space formed between the lower mold and the lower resin sheet are held airtightly. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a thermoplastic resin sheet molding apparatus and a thermoplastic resin sheet molding method.

  When a resin material is applied to an automobile part, it is required to be lightweight, high rigidity and high strength. As means for solving this problem, development of parts having hollow portions inside the resin has been performed. By providing a hollow portion in the resin, the rigidity and strength of the component can be improved in a lightweight manner.

  As a method for producing a resin molded body having such a hollow portion, two resin sheets facing each other are arranged in parallel in a mold and the periphery is fixed, and the resin sheet is preliminarily used using a heat generator. After heating, blown air between a pair of resin sheets to expand the inside and press-bond to the mold, or place a suction port that can be evacuated on the inner wall surface of the mold cavity, and preheated resin sheet and Examples thereof include a vacuum forming method in which a mold cavity inner wall surface is formed while being vacuumed, and a manufacturing method by a vacuum / pressure forming method in which a pressure forming method and a vacuum forming method are combined.

  Specifically, molding of a synthetic resin hollow molded body that has a high reproducibility of a thermoplastic resin sheet molded shape, has high joint strength, and can obtain a large, large area, flat plate shaped hollow molded body. As a method, a vacuum / pressure forming apparatus (Japanese Patent Laid-Open No. 2003-27605) using a structure having a drive means for sliding at least one of the sheet holders to reduce the interval between the resin sheets, or heating the molded product An example is a vacuum forming apparatus (Japanese Patent Laid-Open No. 2002-67137) for vacuum heating and bonding a softened thermoplastic synthetic resin sheet to a molded product.

  However, in the conventional molding method as described above, since the pressure is reduced by the upper and lower molds after preheating, the heating state of the resin sheet changes due to changes in the outside air temperature and other various conditions. However, there is a problem in that a defective shape of a molded product obtained by an actual narrow pressure is generated, and a production yield of a target molded product is lowered.

  Further, in the case of decorating the outer surface of the molded product, even if an attempt is made to attach a decorative sheet for decorating to the outer surface of the molded product in the above-described shaping operation, Since the temperature of the resin sheet is lowered in the shaping process, the decorative sheet is not attached to the molded product (resin sheet), and a good decorative molded product cannot be obtained. There is a problem that the yield decreases.

  In view of such problems, in order to increase the vacuuming speed at the time of shaping, the diameter or number of vacuuming holes in the mold cavity is increased, the surface roughness of the mold cavity is increased, Vacuum pressure forming apparatus using a structure having a driving means for reducing the degree of freedom of the cavity shape of the molding die and further sliding at least one of the sheet holders to reduce the interval between the resin sheets No. 2003-276075). According to this apparatus, since the shaping speed can be increased, there is no problem caused by the decrease in the temperature of the resin sheet in the shaping process as described above.

  However, this method has a problem in that a large number of traces of vacuum holes remain in the molded product, which deteriorates the appearance quality of the molded product. In addition, since the degree of freedom of the cavity shape of the mold is lowered, the degree of freedom of shape design is reduced. Furthermore, when manufacturing a decorative molded product, there is a problem that even if the apparatus as described above is used, the attachment cannot be sufficiently improved, and a sufficient manufacturing yield cannot be realized yet. It was.

  An object of the present invention is to prevent a temperature drop of a resin sheet during shaping, to provide a molded product having a good appearance shape, and to improve the production yield.

In order to achieve the above object, the present invention provides:
An upper mold and a lower mold provided so as to face each other;
A heater portion provided at a substantially central portion of the upper mold and the lower mold;
The upper resin sheet is held in the upward direction of the heater portion so as to be substantially parallel to the upper heating surface of the heater portion, and is substantially parallel to the lower heating surface of the heater portion in the downward direction of the heater portion. And a sheet holding part adapted to hold the lower resin sheet,
A first space formed between the upper mold and the upper resin sheet, a second space formed between the upper resin sheet and the lower resin sheet, and between the lower mold and the lower resin sheet The present invention relates to a thermoplastic resin sheet molding apparatus characterized in that the third space to be formed is kept airtight.

  According to the molding apparatus of the present invention, a heater part is provided at a substantially central part of the molding apparatus, an upper resin sheet is provided so as to be substantially parallel to the upper heating surface of the heater part, A lower resin sheet is provided so as to be substantially parallel, and when the upper resin sheet and the lower resin sheet are formed by the upper mold and the lower mold, the upper resin sheet and the lower resin sheet are heated and softened. I can leave. Therefore, these resin sheets can always be kept at a desired temperature during shaping, and the heat-softened state of the resin sheet can be kept in a desired state.

  Therefore, it becomes possible to suppress molding defects of the molded product due to a decrease in the temperature of the resin sheet and a decrease in manufacturing yield associated therewith during shaping. Furthermore, when the decorative molded product is manufactured, the attachment of the decorative sheet to the molded product (resin sheet) can also be improved, and the shape defect and the manufacturing yield of the decorative molded product can be sufficiently improved. Can do.

  In actual production of a molded product using the molding apparatus of the present invention described above, the upper resin sheet is removed from the upper mold by evacuating the first space and the third space. A resin molded product having a hollow part can be produced by bringing the lower resin sheet into contact with the molding surface and shaping the lower resin sheet with the molding surface of the lower mold. At this time, the second space is preferably in a pressurized state. Thereby, the shapeability of the upper resin sheet and the lower resin sheet can be improved.

  As described above, according to the present invention, it is possible to prevent a decrease in the temperature of the resin sheet during shaping, to provide a molded product having a good appearance shape, and to improve the production yield.

  Details of the present invention, as well as other features and advantages, are described in detail below.

(Molding equipment)
FIG. 1 is a configuration diagram showing an example of the molding apparatus of the present invention. A molding apparatus 10 shown in FIG. 1 includes an upper mold 11 and a lower mold 12 provided so as to face each other, and a heater unit 13 provided at a substantially central portion of the upper mold 11 and the lower mold 12. , And a pair of sheet holding portions 14 provided on both sides of the heater portion 13. The sheet holding unit 14 holds the upper resin sheet S1 in the upward direction of the heater unit 13 so as to be substantially parallel to the upper heating surface of the heater unit 13, and below the heater unit 13 in the downward direction of the heater unit 13. The lower resin sheet S2 is held so as to be substantially parallel to the heating surface.

  The sheet holding portion 14 engages with the outer peripheral wall 111 of the upper mold 11 and the outer peripheral wall 121 of the lower mold 12 to form a first space A1, upper resin formed between the upper mold 11 and the upper resin sheet S1. The second space A2 formed between the sheet S1 and the lower resin sheet S2 and the third space A3 formed between the lower mold 12 and the lower resin sheet S2 are kept airtight. In order to further improve the airtightness from the first space A1 to the third space A3, at least a portion of the sheet holding portion 14 that engages with the upper mold 11 and the lower mold 12 is a rubber sheet or a sponge material. It is preferable to improve the sealing characteristics.

  In addition, a valve 15 is provided continuously to the upper mold 11 so that a predetermined gas is introduced into the first space A1 through the valve and the fine holes 18 formed in the upper mold 11. In addition, the first space A1 can be evacuated to a vacuum by a suction mechanism (not shown). Further, a valve 17 is provided continuously to the lower mold 12 so that a predetermined gas is introduced into the first space A1 through the valve and the fine holes 19 formed in the upper mold 12. The third space A3 is configured to be evacuated to a vacuum by a suction mechanism (not shown).

  The positions where the pores 18 and 19 are formed are not particularly limited as long as they do not affect the appearance of the target resin molded product, and can be formed at arbitrary positions. However, it is preferable that the openings of the pores 18 and 19 are provided so that the portions exposed to the molding surfaces of the molding dies 11 and 12 are located at the ends or corners of the molding surfaces. Further, the diameters of the pores 18 and 19 are not particularly limited, but are preferably 1 mm or less so as not to affect the external shape of the resin molded product. Furthermore, the number of openings of the pores 18 and 19 is also set to an arbitrary number that does not affect the appearance of the resin molded product.

  Further, the seat holding portion 14 is also provided with a valve 16 so that a predetermined gas is introduced into the second space A2. As described above, the first space A1 to the third space A3 are configured to be adjusted to an arbitrary pressure by introducing and exhausting the gas through the valves 15 to 18. Therefore, the valves 15 to 18 function as a pressure variable mechanism.

  Examples of the gas include air, nitrogen gas, and carbon dioxide gas that do not affect the resin sheets S1 and S2 to be molded.

  The upper mold 11 and the lower mold 12 can be produced using, for example, ferrous and non-ferrous metals, ceramic materials, and thermosetting resin materials.

  The heater unit 13 may be a far infrared heater having a maximum energy wavelength in the vicinity of 4 μm, a short wavelength or medium wavelength heater having a maximum energy wavelength in the vicinity of 1 to 3 μm, or the like. Preferably, a far infrared heater whose absorption wavelength matches that of a general thermoplastic resin is used.

  FIG. 2 is a block diagram showing a modification of the molding apparatus shown in FIG. The molding apparatus 20 shown in FIG. 2 basically has the same configuration as the molding apparatus shown in FIG. 1, but differs in that a pressure variable pump 21 is provided continuously with the valves 15 to 17. Therefore, by evacuating the first space A1 to the third space A3 with the variable pressure pump 21 via the valves 15 to 17, the pressures in these spaces can be made equal. The pressure variable pump 21 functions as an additional pressure variable mechanism for the valves 15 to 17 described above.

  FIG. 3 is a block diagram showing another modification of the molding apparatus shown in FIG. The molding apparatus 30 shown in FIG. 3 basically has the same configuration as the molding apparatus shown in FIG. 1, but a decorative sheet holding portion 31 is provided at the center of the lower mold 12, and the decoration is performed at this portion. The difference is that the sheet S3 is held. The decorative sheet holding unit 31 can be configured to provide pores (not shown) in the lower mold 12 and hold the decorative sheet S3 by exhausting through the pores. Further, the lower mold 12 can be provided with a recess, and the decorative sheet S3 can be fixed in the recess, or the decorative sheet S3 can be fixed using a predetermined fixing jig.

  In addition, in the shaping | molding apparatus 30 shown in FIG. 3, although the decorating sheet holding | maintenance part 31 is provided in the lower shaping | molding die 12, it arrange | positions a decorating sheet only in this part, It can also be provided in the mold alone or in both molds.

  1 to 3 includes a driving means (not shown) for moving the heater portion 13 substantially in parallel with the upper resin sheet S1 and the lower resin sheet S2, and the upper resin sheet S1 and the lower resin sheet. The heater unit 13 can be excluded from the second space A2 to the outside by the driving means after the heat softening of S2 or during the heat softening process.

  Furthermore, a narrow pressure means for narrowing the resin molded product is provided when the resin molded product is shaped, and the resin molded product is narrowed via at least one of the upper mold 11 and the lower mold 12. It can be formed by pressing.

(Molding method)
Next, the shaping | molding method using the shaping | molding apparatus mentioned above is demonstrated. First, the basic molding method of the present invention using the apparatus shown in FIG. 1 will be described.

  In the molding method using the molding apparatus 10 shown in FIG. 1, first, the upper resin sheet is made to be substantially parallel to the upper heating surface of the heater unit 13 in the upward direction of the heater unit 13 by the sheet holding unit 14. S1 is held, and the lower resin sheet S2 is held in the downward direction of the heater unit 13 so as to be substantially parallel to the lower heating surface of the heater unit 13.

  Next, a first space A1 formed between the upper mold 11 and the upper resin sheet S1 by engaging the outer peripheral wall 111 of the upper mold 11 and the outer peripheral wall 121 of the lower mold 12 with the sheet holding portion 14, The second space A2 formed between the upper resin sheet S1 and the lower resin sheet S2 and the third space A3 formed between the lower mold 11 and the lower resin sheet S2 are kept airtight.

  Next, the upper resin sheet S1 and the lower resin sheet S2 are heated and softened by the heater unit 13. When the upper resin sheet S1 and the lower resin sheet S2 reach a predetermined temperature and show a predetermined softened state, the first space A1 and the third space A3 are evacuated to a vacuum by a suction mechanism (not shown). Then, as shown in FIG. 4, the upper resin sheet S <b> 1 is brought into contact with the molding surface of the upper molding die 11, and the lower resin sheet S <b> 2 is brought into contact with the molding surface of the lower molding die 12 to be shaped. As a result, a predetermined resin molded product S4 having a hollow portion can be produced.

  Note that the first space A1 and the third space A3 can be evacuated, and at the same time, a predetermined gas can be introduced into the second space A2 to make the inside of the space pressurized. Thereby, the shapeability of the upper resin sheet S1 and the lower resin sheet S2 can be improved. At this time, the pressure in the second space A2 is set to 1 MPa or less, for example.

  Further, at the time of shaping shown in FIG. 4, the heater unit 13 is discharged out of the second space A2 by driving means (not shown) so that the heating and softening operation of the upper resin sheet S1 and the lower resin sheet S2 is completed. I have to. In this case, excessive heat softening of the upper resin sheet S1 and the lower resin sheet S2 can be prevented in advance, and breakage and drawdown of these resin sheets can be prevented in advance. However, instead of excluding the heater part 13 to the outside, the driving of the heater part 13 itself can be stopped and the heat softening operation of the upper resin sheet S1 and the lower resin sheet S2 can be ended. However, in this case, the above-described operational effects cannot be obtained.

  Furthermore, when the upper resin sheet S1 and the lower resin sheet S2 reach a predetermined temperature, taking out of the heater unit 13 to the outside is too slow, and these sheets are heated to a desired temperature or more and are softened. There is. Therefore, in consideration of preliminary heating efficiency in advance, the heater unit 13 takes out the upper resin sheet S1 and the lower resin sheet S2 before reaching a predetermined temperature, heats these sheets with residual heat, and heats the desired sheet. It can be heated to a temperature.

  Further, the same operation can be applied even when the heater unit 13 is not taken out. In this case, the heater unit 13 is driven before the upper resin sheet S1 and the lower resin sheet S2 reach a predetermined temperature. And the sheets are heated by the residual heat to be heated to the desired temperature.

  In addition, depending on the type of thermoplastic resin constituting the upper resin sheet S1 and the lower resin sheet S2, the mechanical strength in the softened state is not sufficient by the heat softening operation by the heater unit 13, and the drawdown is performed as it is. May occur. In this case, the draw-down is prevented by injecting a predetermined gas into the first space A1 to the third space A3 via the valves 15 to 17 and appropriately controlling the pressure in these spaces. be able to. Specifically, in the first space A1 to the third space A3, the drawdown is prevented by maintaining a high pressure on the drawdown side of the upper resin sheet S1 and the lower resin sheet S2.

  For example, in the case where the apparatus shown in FIG. 1 is arranged vertically as shown in the drawing, if the upper resin sheet S1 is drawn down, the draw down occurs downward, so that the inside of the second space A2 The pressure is made higher than the pressure in the first space A3 to prevent the drawdown. Further, when the lower resin sheet S2 is drawn down, the drawdown in this case also occurs downward, so that the pressure in the third space A3 is made higher than the pressure in the second space A2, and the drawdown is performed. To prevent.

  Further, when the thermoplastic resin constituting the upper resin sheet S1 and the lower resin sheet S2 has sufficient mechanical strength in the softened state by the heat softening operation by the heater unit 13, before the resin sheets are shaped In order to prevent unnecessary deformation and to perform the above-described shaping operation satisfactorily, the pressure in the first space A1 to the third space A3 is made equal by using a molding apparatus 20 as shown in FIG. The unnecessary deformation can be prevented.

  Further, when decorating the resin molded product S4, the molding sheet 30 shown in FIG. 3 is used to link the decorative sheet S3 to the resin molded product S4 in conjunction with the shaping operation shown in FIG. It is possible to form a decorated resin molded product S5 as shown in FIG.

  In any of the above cases, after forming the resin molded product S4, at least one of the upper mold 11 and the lower mold 12 is narrowed by a press machine (not shown) or the like, as shown in FIG. It is also possible to form the resin molded product S6. Note that the pressure at the narrow pressure is preferably 400 hPa or less.

  The upper resin sheet S1 and the lower resin sheet S2 can be made of any thermoplastic resin. Specific examples include polyolefin resins such as polyethylene and polypropylene, polystyrene, polycarbonate, acrylonitrile / styrene / butadiene block copolymers, general thermoplastic resins such as nylon, ethylene / propylene block copolymers, and styrene / butadiene blocks. Examples thereof include thermoplastic elastomers such as copolymers, or polymer alloys thereof.

  In addition, in such a resin sheet, a nano combo containing various fillers such as talc and glass fiber, or a fine particle material on the order of several tens of nm much smaller than the wavelength of visible light <380 to 77 Onm>. Jit material may be used. Examples of the fine particle material include clay, talc, and silica. Various commonly used additives such as pigments, lubricants, antistatic agents, and antioxidants may be blended.

  Further, the decorative sheet S3 is made of a material having good adhesiveness with the above-described thermoplastic resin. Further, when the decorative sheet S3 does not have direct adhesiveness, an adhesive layer having adhesiveness with respect to the thermoplastic resin can be interposed therebetween.

  Next, a coating film will be described as a specific example of the decorative sheet S3. As an example of the coating film, there is one configured by laminating a coating film having an acrylic resin composition as a clear layer and a resin base material. Since the acrylic resin composition is transparent, it can be used, for example, as a clear coating film for automobile outer panels.

  Moreover, it is preferable that the said coating film consists of the said clear layer, a colored layer, and a packing material layer, and is integrally molded. Further, the coating film may be laminated in the order of the clear layer, the acrylic colored layer, and the packing material, and may be formed by melt multilayer extrusion film molding or heat lamination molding, or may be laminated in the order of the clear layer, the colored film, and the packing material. Then, the film may be formed by heat lamination.

  On the other hand, the material selection method with good adhesion is appropriately selected from the well-known thermosetting resin-based or thermoplastic resin-based decorative sheet, or for adhesive materials, with an adhesive. Just do it.

  EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention further in full detail, this invention is not limited by this.

(Examples 1-8)
The upper resin sheet S1 and the lower resin sheet S2 are each made of a polycarbonate resin sheet (Iupilon sheet NF-2000 (manufactured by Mitsubishi Engineering Plastics)) with a thickness of 3 mm and an acrylic resin sheet (acrylic L (made by Mitsubishi Rayon)) with a thickness of 3 mm. The decorative sheet S3 was composed of a coating film (AVLOY dry paint film (Mitsubishi Chemical MKV) laminated in the order of a clear layer, an acrylic colored layer, and a backing material) using an acrylic resin composition.

  The upper mold 11 and the lower mold 12 are made of aluminum (ZAS), the heater unit 13 is composed of a far infrared heater, and the far infrared heater set temperature is heated to 400 ° C. and softened at the temperature shown in Table 1. . The pressure at the time of narrow pressure was 133 Pa, and air (Air) was introduced into the second space A2 at 0.2 MPa when the first space A1 and the third space A3 were evacuated. In addition, specific operation followed the operation demonstrated in relation to FIGS.

(Comparative Examples 1-4)
The resin molded product was manufactured using the conventional molding apparatus shown in FIG. In the molding apparatus shown in FIG. 7, after the upper resin sheet S1 and the lower resin sheet S2 held by the sheet holding unit 44 are heated in advance by the heater unit (far infrared heater) 43, the heater unit 43 is moved backward to perform non-heating. In the state, the upper mold 41 and the lower mold 42 were clamped to form a desired resin molded product. When manufacturing the resin molded product, the upper resin sheet S1 and the lower resin sheet S2 are adhered to the molding surfaces of the upper mold 41 and the lower mold 42 by a suction mechanism (not shown), and air is being molded by the needle 45. Introduced into the resin molded product, the upper resin sheet S1 and the lower resin sheet S2 are shaped into the upper mold 41 and the lower mold 42, and the mold is clamped as described above to achieve the desired resin molding Formed an article.

(Performance evaluation)
The evaluation results of the hollow molded body obtained in each example are shown in Tables 1 and 2. The evaluation items are exemplified below.

<Shaping property of hollow molded body>
The appearance of the flat portion and the R portion of the hollow molded body was visually observed. When the shape of the mold cavity was correctly reflected in the appearance of the hollow molded body, the symbol was indicated as “good”, and when it was not reflected, it was indicated as “x”.

<The hollow molding body>
The irregularities generated on the front surface or the back surface of the hollow molded body were visually observed. The symbol was indicated as “good” when there was no irregularity, and the symbol “X” when the irregularity occurred.

<Air trap marks between the surface of the hollow molded body and the mold>
The air accumulation marks generated during the molding of the front or back surface of the hollow molded body were visually observed. When there was no air stagnation mark, the symbol was marked as “good”, and when the air stagnation mark was generated, it was marked as “x”.

<Air trap marks in the gap between the decorative sheet and the resin sheet>
The air accumulation trace which generate | occur | produced in the clearance gap between the decorating sheet and the hollow molded object in the decorative surface of a hollow molded object was observed visually. When there was no air stagnation mark, the symbol was marked as “good”, and when the air stagnation mark was generated, it was marked as “x”.

<Comprehensive judgment>
If all of the evaluation results for the shape of the hollow molded body, the hollow molded body, the air pocket trace between the surface of the hollow molded body and the mold, and the air pocket trace between the decorative sheet and the resin sheet are all good, mark the symbol. A circle is displayed. If any one is defective, a circle is displayed.

  As is apparent from Tables 1 and 2, the hollow molded body and the decorative hollow molded body obtained by the molding apparatus and molding method of the present invention have good shapeability of the hollow molded body, and the hollow molded body has a good shape and hollow molding. It can be seen that there is no air accumulation trace between the body surface and the mold, and no air accumulation trace between the decorative sheet and the resin sheet, the appearance quality is excellent, and the molding method is improved dramatically.

  As described above, the present invention has been described in detail based on the embodiments of the present invention with specific examples. However, the present invention is not limited to the above contents, and all modifications and changes are made without departing from the scope of the present invention. It can be changed.

  For example, in the above specific examples, only the case of forming a hollow molded product has been described. However, the present invention is not limited to other molded products such as a windshield, a side glass, a back door glass, a sunroof, and the like. It can also be used for parts that do not have hollow parts, such as resin outer plates for automobiles that do not have hollow parts such as roof panels, automobile back doors, and side doors.

It is a block diagram which shows an example in the shaping | molding apparatus of the thermoplastic resin sheet of this invention. It is a block diagram which shows the modification of the shaping | molding apparatus shown in FIG. It is a block diagram which shows the other modification of the shaping | molding apparatus shown in FIG. It is a figure which shows one process in the shaping | molding method of the thermoplastic resin sheet of this invention. It is an external view which shows an example of the resin molded product obtained with the shaping | molding apparatus and molding method of this invention. It is a figure which shows one process in the shaping | molding method of the thermoplastic resin sheet of this invention. It is a block diagram which shows an example in the shaping | molding apparatus of the conventional thermoplastic resin sheet. It is a figure which shows one process in the shaping | molding method of the conventional thermoplastic resin sheet.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10,20,30 Molding apparatus 11 Upper mold 12 Lower mold 13 Heater part 14 Sheet holding part 15, 16, 17 Valve 18, 19 Pore 21 Pressure variable pump 31 Decorating sheet holding part
S1 Upper resin sheet
S2 Lower resin sheet
S3 decorative sheet
S4 resin molded product
S5 Decorated resin molded product
S6 Narrow pressure plastic molded product

Claims (16)

An upper mold and a lower mold provided so as to face each other;
A heater portion provided at a substantially central portion of the upper mold and the lower mold;
The upper resin sheet is held in the upward direction of the heater portion so as to be substantially parallel to the upper heating surface of the heater portion, and is substantially parallel to the lower heating surface of the heater portion in the downward direction of the heater portion. And a sheet holding part adapted to hold the lower resin sheet,
A first space formed between the upper mold and the upper resin sheet, a second space formed between the upper resin sheet and the lower resin sheet, and between the lower mold and the lower resin sheet An apparatus for molding a thermoplastic resin sheet, characterized in that the third space to be formed is kept airtight.   The first space, the second space, and the third space provide a sealing function to the sheet holding unit, and by engaging the sheet holding unit with the upper mold and the lower mold, The apparatus for molding a thermoplastic resin sheet according to claim 1, wherein the apparatus is hermetically maintained.   The molding apparatus has a suction mechanism, and exhausts the first space and the third space to a vacuum via the upper mold and the lower mold, and the upper resin sheet is evacuated to the upper mold. And forming the resin molded product having a hollow part by bringing the lower resin sheet into contact with the molding surface of the lower mold and shaping the resin sheet. The apparatus for molding a thermoplastic resin sheet according to claim 1 or 2.   The molding apparatus includes a pressure mechanism, pressurizes the second space, shapes the upper resin sheet by bringing it into contact with a molding surface of the upper mold, and moves the lower resin sheet to the lower 4. The apparatus for molding a thermoplastic resin sheet according to claim 3, wherein the molding is performed by contacting with a molding surface of a molding die to produce a resin molded product having a hollow portion.   The molding apparatus has a pressure variable mechanism, and controls the respective pressures in the first space, the second space, and the third space to complete the heat softening process or in the heat softening process. The apparatus for molding a thermoplastic resin sheet according to any one of claims 1 to 4, wherein drawing of the sheet and the lower resin sheet is prevented.   The molding apparatus has an additional pressure variable mechanism, and is configured to equalize the pressures in the first space, the second space, and the third space, respectively. The thermoplastic resin sheet forming apparatus according to any one of 5.   The molding apparatus includes a driving unit that moves the heater portion substantially parallel to the upper resin sheet and the lower resin sheet, and after the heat softening of the upper resin sheet and the lower resin sheet is completed or during the heat softening process. The apparatus for molding a thermoplastic resin sheet according to any one of claims 1 to 6, wherein the heater is excluded from the third space to the outside by the driving means.   The molding of the thermoplastic resin sheet according to any one of claims 3 to 7, further comprising a narrow pressure means for narrowing the resin molded product during shaping of the resin molded product. apparatus.   A decorative sheet holding part is provided in at least one of the upper mold and the lower mold, and the decorative sheet held in the decorative sheet holding part is attached to the outer surface of the resin molded product having the hollow part. The apparatus for molding a thermoplastic resin sheet according to any one of claims 3 to 7, characterized in that the apparatus is configured as described above. A method for producing the resin molded article having the hollow portion using the molding apparatus according to claim 3,
The upper resin sheet is held by the sheet holding portion in the upward direction of the heater portion so as to be substantially parallel to the upper heating surface of the heater portion, and the heater portion is heated downward in the downward direction of the heater portion. A step of holding the lower resin sheet so as to be substantially parallel to the surface;
The first space formed between the upper mold and the upper resin sheet by engaging the upper mold and the lower mold provided to face each other with the sheet holding portion, Maintaining the second space formed between the upper resin sheet and the lower resin sheet, and the third space formed between the lower mold and the lower resin sheet in an airtight manner;
A step of heating and softening the upper resin sheet and the lower resin sheet by the heater unit;
The suction mechanism evacuates the first space and the third space through the upper mold and the lower mold, and contacts the upper resin sheet with the molding surface of the upper mold. And forming the resin molded product having the hollow portion by shaping the lower resin sheet by bringing it into contact with the molding surface of the lower mold, and
A method for forming a thermoplastic resin sheet, comprising:   The pressurizing mechanism brings the second space into a pressurized state, the upper resin sheet is brought into contact with the molding surface of the upper molding die, and the lower resin sheet is molded into the molding surface of the lower molding die. The method for forming a thermoplastic resin sheet according to claim 10, further comprising a step of forming the resin molded product having the hollow portion by forming the resin by contacting with a resin.   The pressure variable mechanism controls the respective pressures in the first space, the second space, and the third space, and after the heat softening is finished or in the process of the heat softening, The method for molding a thermoplastic resin sheet according to claim 10 or 11, further comprising a step of preventing drawing of the resin sheet.   13. The method according to claim 10, further comprising the step of equalizing each pressure in the first space, the second space, and the third space by an additional pressure variable mechanism. The molding method of the thermoplastic resin sheet as described in 2.   The driving unit moves the heater part substantially parallel to the upper resin sheet and the lower resin sheet, and the driving of the upper resin sheet and the lower resin sheet after the heat softening is completed or during the heat softening process. The method for molding a thermoplastic resin sheet according to any one of claims 10 to 13, wherein the heater portion is excluded from the third space to the outside by means.   The step of narrowing at least one of the upper resin sheet in contact with the upper molding surface and the lower resin sheet in contact with the lower molding surface during the shaping is characterized by the above-mentioned. The method for forming a thermoplastic resin sheet according to any one of 14.   The process of holding a decorating sheet in the decorating sheet holding part provided in at least one of the upper mold and the lower mold, and attaching the decorating sheet to the outer surface of the resin molded product during the shaping The method for forming a thermoplastic resin sheet according to any one of claims 10 to 15, comprising:

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