JP2006123210A - Method and apparatus for molding thermoplastic resin sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enhance the manufacturing yield of a molded product especially a hollow molded product having a hollow part by suppressing the formation of an air sump between resin sheets or the partial welding of the resin sheets in the molded product, especially the hollow molded product having the hollow part. <P>SOLUTION: A first space formed between an upper resin sheet S1 and a lower resin sheet S2, both of which are held almost in parallel to heating surfaces of heaters 13 and 14, are airtightly held by a sheet holding part and the upper and lower resin sheets are heated and softened by the heaters. Subsequently, the heaters are replaced with an upper mold 11 and a lower mold 12 and the upper and lower molds are arranged so as to hold the upper and lower resin sheets. Next, the first space is set to a pressurized state not only to bring the upper resin sheet into contact with the molding surface of the upper mold to shape it but also to bring the lower resin sheet into contact with the molding surface of the lower mold to shape it and one-side ends parts of the upper and lower resin sheets are cooled and solidified by cooling parts 17 and 18 to manufacture a resin molded product having a hollow part. <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 of manufacturing a resin molded product having such a hollow portion, two resin sheets that face each other are arranged in parallel in a mold, and the periphery is fixed. 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 thermoplastic resin sheet molding shape is highly reproducible, the joint strength is high, and a synthetic resin hollow molding product capable of obtaining a large-sized, large-area, flat-plate-shaped hollow molding product. 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, when trying to produce a flat, hollow, molded product having a large size, a large area, and a narrow space, the cavity shape of the mold and the vacuuming speed in the cavity Depending on the surface roughness of the cavity and the like, air accumulation (including fine irregularities on the surface of the resin sheet) between the heat-softened resin sheets, or partial welding in the narrow space of the hollow molded product may occur. There was a problem that the yield of molded products could not be increased.

  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.

JP 2003-27605 A JP 2002-67137 A Japanese Patent Laid-Open No. 2003-276075

  The present invention is a molded product, particularly a hollow molded product having a hollow portion, and it is possible to perform an air reservoir or partial welding between resin sheets without depending on the size, area, narrow internal space, and shape. It aims at suppressing and improving the manufacture yield of the said molded article.

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 located at a substantially central portion of the upper mold and the lower mold;
A sheet holding unit configured to hold the upper resin sheet and the lower resin sheet so as to be substantially parallel to the heating surface of the heater unit;
A cooling unit for cooling and solidifying the upper resin sheet and an end of the lower resin sheet, provided on the outside of the upper mold and the lower mold;
The sheet holding portion holds at least a first space formed between the upper resin sheet and the lower resin sheet in an airtight manner, and the upper mold and the lower mold are arranged before and after the heating operation with the heater portion. In the case of shaping, the airtightness of the first space is maintained by cooling and solidifying the end portions of the upper resin sheet and the lower resin sheet by the cooling portion. The present invention relates to a thermoplastic resin sheet molding apparatus.

  The present inventors diligently studied to find out the cause of the above-described air accumulation and partial welding during molding of a molded product, particularly a hollow molded product. As a result, the following facts have been discovered. In the case where two resin sheets are processed by softening with heat, and a hollow molded product is produced, the space formed between the two resin sheets is kept airtight, and is appropriately added to the space. The desired hollow is formed by introducing a pressurized gas or evacuating the space formed on the back surface of the two resin sheets to bring the two resin sheets into contact with a mold. A molded product is produced.

  However, the airtightness of the space is reduced to some extent, particularly at the stage of the shaping operation. Therefore, when the hollow molded product becomes large and wide, and the internal space is narrowed or the ratio of the flat plate portion is increased, air accumulation and partial welding between the resin sheets frequently occur. I found.

  In view of the discovery of such facts, as described above, the present inventors have provided a cooling portion outside the upper mold and the lower mold, and at the time of shaping, the end portion of the resin sheet is used as the cooling portion. By contacting, the part is cooled and solidified, and as a result, the space formed between the two resin sheets can sufficiently retain its airtightness even during shaping, It has been found that the above-described air accumulation and partial welding can be prevented. The present invention has been made based on the discovery of such facts.

  According to the present invention, in a molded product, particularly a hollow molded product having a hollow portion, an air reservoir or partial welding between resin sheets is not dependent on the size, area, narrow internal space, and shape. The production yield of the molded product can be improved.

  In a preferred embodiment of the present invention, the cooling part includes at least one of an upper cooling part and a lower cooling part, the upper cooling part is provided in the upper mold, and the lower cooling part is provided in the lower mold. It can be provided. In this case, the configuration and operability of the entire apparatus can be simplified, and the outer peripheral portion of the molded product body where the molding die is located can be effectively cooled and solidified.

  The upper cooling part and the lower cooling part can be provided movably or fixedly depending on the shape of the molded product, the shape of the mold, and the narrow pressure operation that can be appropriately provided later. You can also.

  Moreover, it is preferable that the said upper cooling part and the said lower cooling part have an inclination part in the side which contacts the said upper resin sheet and the said lower resin sheet, respectively. Thus, the cooling unit can be easily detached from the resin sheet after the upper resin sheet and the lower resin sheet are cooled and solidified by the upper cooling unit and the lower cooling unit.

  According to the present invention, the upper resin sheet and the lower resin sheet can be shaped by bringing them into contact with the upper mold and the lower mold, respectively, to obtain a desired molded product. The molded product can be obtained by performing a pressure operation.

  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 a concave upper mold 11 and a convex lower mold 12 provided so as to face each other, and a substantially central portion of the upper mold 11 and the lower mold 12. An upper heater portion 13 and a lower heater portion 14 provided, and a sheet holding portion 15 provided so as to be positioned on both sides of the heater portions 13 and 14 are provided. The sheet holding portion 15 holds the upper resin sheet S1 so as to be substantially parallel to the lower heating surface of the upper heater portion 13, and supports the lower resin sheet S2 so as to be substantially parallel to the upper heating surface of the lower heater portion 14. In addition, the first space A1 between the upper resin sheet S1 and the lower resin sheet S2 is kept airtight.

  Further, the upper mold 11 and the lower mold 12, and the upper heater section 13 and the lower heater section 14 are provided to be exchangeable, and the upper resin sheet S1 and the lower resin sheet S2 are heated and softened by the heater sections 13 and 14. Then, the heater parts 13 and 14 are moved and removed, and the upper mold 11 and the lower mold 12 are arranged facing each other as shown in the figure so as to sandwich the resin sheets S1 and S2, and will be described in detail below. It can be made to use for the shaping operation described.

  Further, the sheet holding unit 15 is provided with a gas pipe 16 with a valve constituting a pressurizing mechanism, and a predetermined pressurization gas is fed into the first space A1 to bring it into a pressurized state. It is used for the shaping operation described below.

  Further, upper cooling portions 17 are provided on both side surfaces of the upper mold 11, and lower cooling portions 18 are provided on both side surfaces of the lower mold 12. The upper cooling part 17 and the lower cooling part 18 are provided on the entire side surfaces of the upper mold 11 and the lower mold 12, and in the shaping operation described below, the upper resin sheet S1 and the lower resin sheet are provided. The entire outer periphery of S2 is configured to be cooled and solidified.

  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. Further, it is preferable that at least a portion of the sheet holding portion 15 that engages with the upper resin sheet S1 and the lower resin sheet S2 is made of a rubber-based sheet or a sponge material to improve the sealing characteristics.

  The heater units 13 and 14 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 1-3 μm, or the like. Preferably, a far infrared heater whose absorption wavelength matches that of a general thermoplastic resin is used. Moreover, a hot air heater etc. can be used instead of such a hot wire heater.

  The upper cooling unit 17 and the lower cooling unit 18 are made of a material having high thermal conductivity such as (steel material for mold: SCM) and (aluminum material for mold: ZAS), and the upper resin sheet S1 and Since the area of the portion in contact with the lower resin sheet S2 is kept large to some extent, such an end portion is brought into contact with the heat softened upper resin sheet S1 and the lower resin sheet S2 in the shaping operation. Can be rapidly cooled and solidified in comparison with other parts, for example, the molded article body. Therefore, even during shaping, the airtightness of the first space A1 between the upper resin sheet S1 and the lower resin sheet S2 is sufficiently maintained, and air production, partial welding, etc. are suppressed, and the production yield of the molded product is increased. Can be improved.

  Further, the upper cooling unit 17 and the lower cooling unit 18 can be provided movably or fixedly according to the shape of the molded product, the shape of the molding die, and the narrow pressure operation that can be appropriately provided later. It can also be provided.

  2 and 3 are enlarged views of the upper cooling unit 17 and the lower cooling unit 18 shown in FIG. As is apparent from FIGS. 1 to 3, in the molding apparatus 10 in this example, the upper cooling unit 17 and the lower cooling unit 18 have the inclined portions 17 </ b> A and 18 </ b> A on the side in contact with the upper resin sheet S <b> 1 and the lower resin sheet S <b> 2. Have. Thereby, after the upper resin sheet S1 and the lower resin sheet S2 are cooled and solidified by the upper cooling unit 17 and the lower cooling unit 18, the cooling unit can be easily detached from the resin sheet.

  The inclination angles θ and φ of the inclined portions 17A and 18A are preferably 4 degrees or more with respect to the upper resin sheet S1 and the lower resin sheet S2, respectively. Thereby, the above-described operational effects can be further increased.

  Moreover, the shaping | molding apparatus 10 shown in FIG. 1 can be provided with narrow pressure means, such as a press machine which is not shown in figure. In this case, the upper resin sheet S1 and the lower resin sheet S2 are brought into contact with the upper molding die 11 and the lower molding die 12, and a predetermined shaping operation is performed by narrowing the pressure by the narrowing means, and the target molded product Will get.

  FIG. 4 is a block diagram showing another example of the molding apparatus of the present invention. In the molding apparatus shown in this example, the same or similar components as those of the molding apparatus shown in FIG.

  In the molding apparatus 20 shown in FIG. 4, the upper mold 11 and the lower mold 12 are provided with pores 21 and 23, respectively, and suction pipes 22 and 24 with valves constituting the suction mechanism are provided at the rear thereof. Unlike the molding apparatus 10 shown in FIG. 1, the other components are basically the same as those of the molding apparatus 10 shown in FIG.

  In the molding apparatus 20 shown in FIG. 4, in the shaping operation shown below, the second space A2 formed between the upper mold 11 and the upper resin sheet S1, and the lower mold 12 and the lower resin sheet S2 are formed. The inside of the third space A3 is kept airtight, and the inside of the second space A2 and the third space A3 is evacuated by the exhaust means (not shown) through the pores 21 and 23 and the suction pipes 22 and 24. Then, it is used for the shaping operation described in detail below.

  Although not clear from the figure, the airtight maintenance of the second space A2 and the third space A3 is achieved by the upper mold 11 and the lower mold 12 engaging with the sheet holding part 15, respectively. Can do. From this point of view, it is preferable that at least a portion of the sheet holding portion 15 that comes into contact with the upper mold 11 and the lower mold 12 is made of a rubber-based sheet or a sponge material to improve its sealing characteristics.

  The installation positions of the suction pipes 22 and 24, that is, the installation positions of the pores 21 and 23 are not particularly limited as long as they do not affect the external shape of the target resin molded product. It can be formed in the position. However, it is preferable that the openings of the pores 21 and 23 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 21 and 23 are not particularly limited, but are preferably 1 mm or less so as not to affect the appearance of the molded product. Furthermore, the number of openings of the pores 21 and 23 is also set to an arbitrary number that does not affect the appearance of the molded product.

  In addition, in the shaping | molding apparatus 20 shown in FIG. 4, since the gas piping 16 is left in addition to the suction piping 22 and 24, in the shaping operation explained in full detail below, suction operation and pressurization operation were utilized. Shaping can be performed. However, in the molding apparatus 20 shown in FIG. 4, it is not always required to pressurize in the shaping operation, so the gas pipe 16 can be omitted.

  FIG. 5 is a configuration diagram showing a modification of the molding apparatus shown in FIG. In the molding apparatus shown in this example, the same or similar components as those of the molding apparatus shown in FIG.

  In the molding apparatus 10 shown in FIG. 1, a concave-shaped upper molding die 11 and a convex-shaped lower molding die 12 are provided. As a result, a molded product having a narrow internal space by a shaping operation described in detail below. Will be completed. On the other hand, in the molding apparatus 30 shown in FIG. 5, since both the upper molding die 11 and the lower molding die 12 have a concave shape, compared with the molding apparatus 10 shown in FIG. It will be completed. However, even in this case, the cooling portions 17 and 18 can cool and solidify the end portions of the upper resin sheet S1 and the lower resin sheet S2, so that the airtightness of the first space A1 can be improved during shaping. It can hold | maintain sufficiently and can suppress an air pool and partial welding in resin sheet S1 and S2.

  However, air accumulation and partial welding are more likely to occur as the internal space of the molded product to be formed becomes narrower. Specifically, the accumulation using the molding apparatus 10 having the convex mold shown in FIG. In shape operation, air accumulation and partial welding are more likely to occur. Therefore, the effect of maintaining the airtightness of the first space A1 by cooling and solidifying the upper resin sheet S1 and the lower resin sheet S2 by the cooling units 17 and 18 is more effective in the shaping operation using the molding apparatus 10 shown in FIG. Will come out.

  FIG. 6 is a configuration diagram showing a modification of the molding apparatus shown in FIG. In the molding apparatus shown in this example, the same or similar components as those of the molding apparatus shown in FIG.

  In the shaping | molding apparatus 40 shown in FIG. 6, the decorating sheet holding | maintenance part 41 is provided in the recessed part of the upper shaping | molding die 11, and the decorating sheet S3 is hold | maintained in the holding | maintenance part. In this case, in the shaping operation described in detail below, the decorative sheet S3 is attached to the outer surface of the molded product body, and the intended molded product is decorated.

(Molding method)
Next, the shaping | molding method using the shaping | molding apparatus mentioned above is demonstrated. Initially, the shaping | molding method using the apparatus shown in FIG. 1 is demonstrated. 7-10 is a figure for demonstrating the shaping | molding procedure in the shaping | molding method at the time of using the shaping | molding apparatus shown in FIG.

  First, as shown in FIG. 7, the upper resin sheet S <b> 1 and the lower resin sheet S <b> 2 are made substantially parallel to the heating surface of the upper heater unit 13 and the heating surface of the lower heater unit, respectively, so that the sheet holding unit 15 In addition, the first space A1 formed between the resin sheets is hermetically maintained. Next, the upper resin sheet S1 and the lower resin sheet S2 are heated to a predetermined temperature by the upper heater portion 13 and the lower heater portion 14, respectively, and are softened. Next, as shown in FIG. 8, the upper heater portion 13 and the lower heater portion 14 are replaced with the upper forming die 11 and the lower forming die 12, respectively, and the upper forming die 11 and the lower forming die 12 are sandwiched between the resin sheets S1 and S2. Thus, it arrange | positions so that it may mutually oppose.

  Next, as shown in FIG. 9, the upper mold 11 and the lower mold 12 are brought close to each other, and pressurized gas is introduced into the first space A1 from the gas pipe 16 to bring the first space A1 into a pressurized state. The upper resin sheet S1 is brought into contact with the molding surface of the upper mold 11 and the lower resin sheet S2 is brought into contact with the molding surface of the lower mold 12 to shape these resin sheets. At this time, since the end portions of the upper resin sheet S1 and the lower resin sheet S2 are cooled and solidified by the upper cooling portion 17 and the lower cooling portion 18, the first space A1 has its airtightness even during the shaping operation. It will be able to hold enough. Therefore, it is possible to improve the production yield of the molded product by suppressing the air accumulation or partial welding of the resin sheets S1 and S2.

  The pressurized gas is not particularly limited, and representative examples include compressed air, nitrogen, carbon dioxide gas and the like discharged from the compressor. Nitrogen gas is preferred. In order to increase the cooling rate of the molded product after shaping and shorten the molding cycle, it is preferable to use carbon dioxide gas.

  Next, as shown in FIG. 10, if necessary, the upper mold 11 and the lower mold 12 are narrowed by a narrow pressure means such as a pressing machine (not shown), and shaped by contacting the molding surface of the mold. The surface can be further compacted.

  FIG. 11 is a schematic view showing an example of a hollow molded product obtained in this manner. In this example, since the shaping is carried out using the convex upper mold 11 and the concave lower mold 12, the hollow interior A4 of the obtained hollow molded product S4 is extremely narrowed. Has been. However, since the end portions of the resin sheets S1 and S2 are cooled and solidified by the cooling units 17 and 18 during shaping, the airtightness of the first space A1 can be sufficiently maintained. Therefore, even when a molded product having a narrow hollow interior as shown in FIG. 11 is produced, air accumulation, partial welding, and the like are suppressed, and the production yield of the molded product is improved.

  In addition, in the shaping | molding apparatus 10 shown in FIG. 1, since the inclination parts 17A and 18A are provided in the side which contacts the upper resin sheet S1 and the lower resin sheet S2 in the upper cooling part 17 and the lower cooling part 18, respectively, shaping Even when the end portions of these resin sheets are cooled and solidified at the time, the cooling portions 17 and 18 can be easily detached from the resin sheet.

  Next, a molding method using the apparatus shown in FIG. 4 will be described. 12-14 is a figure for demonstrating the shaping | molding procedure in the shaping | molding method at the time of using the shaping | molding apparatus shown in FIG.

  First, similarly to the case of using the molding apparatus shown in FIG. 1, as shown in FIG. 7, the upper resin sheet S1 and the lower resin sheet S2 are heated to the heating surface of the upper heater portion 13 and the lower heater portion, respectively. The sheet is held by the sheet holding unit 15 so as to be substantially parallel to the surface, and the first space A1 formed between the resin sheets is held airtight. Next, the upper resin sheet S1 and the lower resin sheet S2 are heated to a predetermined temperature by the upper heater portion 13 and the lower heater portion 14, respectively, and are softened. Next, as shown in FIG. 12, the upper heater part 13 and the lower heater part 14 are respectively replaced with an upper mold 11 and a lower mold 12 provided with pores and suction pipes. 12 are arranged opposite to each other so as to sandwich the resin sheets S1 and S2.

  Next, as shown in FIG. 13, the upper mold 11 and the lower mold 12 are engaged with the sheet holding portion 15, and the second mold formed between the upper mold 11 and the upper resin sheet S <b> 1 held airtight. The space A2 and the third space A3 formed between the lower mold 12 and the lower resin sheet S2 are evacuated to a vacuum by an evacuation unit (not shown) through the pores 21 and 23 and the suction pipes 22 and 24. Then, the upper resin sheet S1 comes into contact with the molding surface of the upper mold 11 and the lower resin sheet S2 comes into contact with the molding surface of the lower mold 12 so that these resin sheets are shaped.

  Also in this case, since the end portions of the upper resin sheet S1 and the lower resin sheet S2 are cooled and solidified by the upper cooling portion 17 and the lower cooling portion 18 during the shaping, the first space A1 is subjected to the shaping operation. In this case, the airtightness can be sufficiently maintained. Therefore, it is possible to improve the production yield of molded products by suppressing the air accumulation and partial welding of the resin sheets S1 and S2.

  Next, as shown in FIG. 14, if necessary, the upper mold 11 and the lower mold 12 are narrowed by a narrow pressure means such as a pressing machine (not shown), and are shaped by contacting the molding surface of the mold. The surface can be further compacted.

  In the molding apparatus 20 shown in FIG. 4, since the gas pipe 16 remains, the pressurized gas as described above is supplied to the first space simultaneously with the evacuation of the second space A2 and the third space A3. It is possible to combine the shaping operation by introducing the space A1 into a pressurized state. In this case, the shapeability of the resin sheets S1 and S2 is further increased.

  Even when the molding apparatus 30 shown in FIG. 5 is used, a molded product can be produced according to the same molding method as described above. Moreover, also when using the shaping | molding apparatus 40 shown in FIG. 6, only a decoration is given to a molded article main body and the basic shaping | molding method follows the content as mentioned above.

  Note that the pressure in the first space A1 due to the introduction of the pressurized gas can be appropriately set based on, for example, 1 MPa. Moreover, when performing narrow pressure shaping, the pressure of the space formed in the resin sheets S1 and S2, the upper mold 11 and the lower mold 12 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.

  Further, in such a resin sheet, a nano combo in which 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 770 nm> is blended. 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. Moreover, when decorating sheet S3 does not have direct adhesiveness, it can be made to interpose the adhesive layer which has adhesiveness with respect to the said thermoplastic resin.

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

(Examples 1-4)
Upper resin sheet S1 and lower resin sheet S2 are made from a polycarbonate resin sheet (Iupilon sheet NF-2000 (manufactured by Mitsubishi Engineering Plastics)) having a thickness of 3 mm and an acrylic resin sheet (acrylite L (made by Mitsubishi Rayon)) having a thickness of 3 mm. Configured. In Examples 1 and 3, molding was performed using the molding apparatus shown in FIG. 1 according to the procedure shown in FIGS. In Examples 2 and 4, molding was performed using the molding apparatus shown in FIG. 4 according to the procedure shown in FIGS. Moreover, the pressure in the 1st space formed between resin sheets was 0.5 Mpa, and the pressure of the narrow pressure was suitably controlled using a 10-ton press so that a predetermined | prescribed hollow molded product could be obtained.

(Comparative Examples 1-4)
Molding was performed according to the procedure shown in FIGS. 7 to 10 and FIGS. 12 to 14 using a molding apparatus having no cooling section as shown in FIGS. Also in this case, Comparative Examples 1 and 3 were carried out according to the procedure shown in FIGS. 7 to 10, and Comparative Examples 2 and 4 were carried out according to the procedure shown in FIGS.

(Performance evaluation)
Table 1 shows the evaluation results of the hollow molded articles obtained in each example. The evaluation items are exemplified below.

<Rupture of cooling solidification part>
During the molding process, the cooling solidified portion was visually observed for rupture. In the case where no rupture occurred, the symbol was indicated as “Good” as “Good”, and in the case where rupture occurred, “×” is shown in Table 1.
<Sink>
The appearance of the upper and lower flat portions of the molded product was visually observed. When there is no sink mark, the symbol is indicated as “good”, and when sink mark is generated, “×” is shown in Table 1.
<Welding of hollow part>
The hollow part was visually observed. When there is no welding in the hollow portion, the symbol is shown as “Good” as “Good”, and when welding has occurred, “×” is shown in Table 1.
<Comprehensive judgment>
When all the evaluation results of the sink marks and hollow ridges of the molded product were good, the symbol was indicated with a circle, and when any of them was defective, the symbol was indicated with a cross.

  As is apparent from Table 1, the molded product obtained according to the molding apparatus and molding method of the present invention is free from rupture, sink marks, and welding of the hollow portion, and is excellent in appearance quality. Therefore, it can be seen that the production yield of the desired molded product can be dramatically improved.

  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-described specific example, the upper heater portion and the lower heater portion are provided so as to be exchangeable with the upper mold and the lower mold, but these may be integrally provided. In this case, after the resin sheet is heated and softened by the heater unit, the heater unit may be detached from the mold, that is, the molding apparatus.

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 figure which expands and shows the cooling part of the shaping | molding apparatus shown in FIG. Similarly, it is a figure which expands and shows the cooling part of the shaping | molding apparatus shown in FIG. It is a block diagram which shows the other 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 an example of the shaping | molding method of the thermoplastic resin sheet of this invention. FIG. 8 is a diagram showing a step subsequent to the step shown in FIG. 7. FIG. 9 is a diagram showing a step subsequent to the step shown in FIG. 8. FIG. 10 is a diagram showing a step subsequent to the step shown in FIG. 9. 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 other example of the shaping | molding method of the thermoplastic resin sheet of this invention. FIG. 13 is a diagram showing a step subsequent to the step shown in FIG. 12. FIG. 14 is a diagram showing a step subsequent to the step shown in FIG. 13.

Explanation of symbols

10, 20, 30, 40 Molding device 11 Upper mold 12 Lower mold 13 Upper heater section 14 Lower heater section 15 Sheet holding section 16 Gas piping 17 Upper cooling section 18 Lower cooling section 17A Upper cooling section inclined section 18A Lower cooling Inclined part 21, 22 Fine pores 23, 24 Suction piping 41 Decorating sheet holding part S1 Upper resin sheet S2 Lower resin sheet S3 Decorating sheet S4 Resin molded product

Claims (15)

An upper mold and a lower mold provided so as to face each other;
A heater portion located at a substantially central portion of the upper mold and the lower mold;
A sheet holding unit configured to hold the upper resin sheet and the lower resin sheet so as to be substantially parallel to the heating surface of the heater unit;
A cooling unit for cooling and solidifying the upper resin sheet and an end of the lower resin sheet, provided on the outside of the upper mold and the lower mold;
The sheet holding portion holds at least a first space formed between the upper resin sheet and the lower resin sheet in an airtight manner, and the upper mold and the lower mold are arranged before and after the heating operation with the heater portion. In the case of shaping, the airtightness of the first space is maintained by cooling and solidifying the end portions of the upper resin sheet and the lower resin sheet by the cooling portion. An apparatus for molding a thermoplastic resin sheet, characterized in that   The cooling unit includes at least one of an upper cooling unit and a lower cooling unit, the upper cooling unit is provided in the upper mold, and the lower cooling unit is provided in the lower mold. The apparatus for molding a thermoplastic resin sheet according to claim 1.   The apparatus for molding a thermoplastic resin sheet according to claim 2, wherein the upper cooling part and the lower cooling part are provided movably with respect to the upper mold and the lower mold, respectively.   The apparatus for molding a thermoplastic resin sheet according to claim 2, wherein the upper cooling part and the lower cooling part are fixedly provided to the upper mold and the lower mold, respectively.   The heat according to any one of claims 2 to 4, wherein the upper cooling part and the lower cooling part have an inclined part on the side in contact with the upper resin sheet and the lower resin sheet, respectively. Plastic resin sheet forming equipment.   The thermoplasticity according to claim 5, wherein an inclination angle of the inclined part of the upper cooling part and the lower cooling part is 4 degrees or more with respect to the upper resin sheet and the lower resin sheet. Resin sheet molding equipment.   The first space is configured to provide a sealing function to the sheet holding portion, and to hold the sheet holding portion in an airtight manner by engaging the sheet holding portion with the upper mold and the lower mold. The molding apparatus of the thermoplastic resin sheet as described in any one of Claims 1-6.   The molding apparatus includes a pressure mechanism, pressurizes the first 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 surface. The molding of the thermoplastic resin sheet according to any one of claims 1 to 7, wherein a molded resin product having a hollow portion is produced by contacting with a molding surface of a molding die. apparatus.   The molding apparatus has a suction mechanism, and the second space formed by the upper mold and the upper resin sheet and the third space formed by the lower mold and the lower resin sheet are airtight. The suction mechanism is used to evacuate the second space and the third space through the upper mold and the lower mold, and the upper resin sheet is removed from 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 molding apparatus of the thermoplastic resin sheet as described in any one of Claims 1-8.   The molding of the thermoplastic resin sheet according to any one of claims 1 to 9, further comprising a narrowing 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 1 to 10, wherein the apparatus is configured as described above. A method for producing the resin molded product having the hollow portion using the molding apparatus according to claim 8,
A step of holding the upper resin sheet and the lower resin sheet by the sheet holding unit so as to be substantially parallel to a heating surface of the heater unit;
The first mold formed between the upper resin sheet and the lower resin sheet is hermetically sealed by engaging the upper mold and the lower mold provided so as to face each other with the sheet holding portion. A step of holding
A step of heating and softening the upper resin sheet and the lower resin sheet by the heater unit;
After heating and softening the upper resin sheet and the lower resin sheet, the heater portion is replaced with the upper mold and the lower mold, and the upper mold and the lower mold are replaced with the upper resin sheet and the lower resin. A step of placing the sheet so as to sandwich it;
The pressure mechanism causes the first space to be in a pressurized state, the upper resin sheet is brought into contact with the molding surface of the upper mold, and the lower resin sheet is molded into the molding surface of the lower mold. Forming the resin molded product having the hollow part by cooling and solidifying the end part of the upper resin sheet and the lower resin sheet in the cooling part,
A method for forming a thermoplastic resin sheet, comprising: A method for producing the resin molded article having the hollow portion using the molding apparatus according to claim 9,
A step of holding the upper resin sheet and the lower resin sheet by the sheet holding unit so as to be substantially parallel to a heating surface of the heater unit;
The first mold formed between the upper resin sheet and the lower resin sheet is hermetically sealed by engaging the upper mold and the lower mold provided so as to face each other with the sheet holding portion. A step of holding
A step of heating and softening the upper resin sheet and the lower resin sheet by the heater unit;
After heating and softening the upper resin sheet and the lower resin sheet, the heater portion is replaced with the upper mold and the lower mold, and the upper mold and the lower mold are replaced with the upper resin sheet and the lower resin. While sandwiching the sheet, the second space formed by the upper mold and the upper resin sheet and the third space formed by the lower mold and the lower resin sheet are hermetically maintained. And arranging the process,
The suction mechanism evacuates the second space and the third space through the upper mold and the lower mold and brings the upper resin sheet into contact with the molding surface of the upper mold. And shaping the lower resin sheet by bringing it into contact with the molding surface of the lower mold, and cooling and solidifying the ends of the upper resin sheet and the lower resin sheet in the cooling part, Producing the resin molded product having a portion;
A method for forming a thermoplastic resin sheet, comprising:   A 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 by the narrowing means; The method for forming a thermoplastic resin sheet according to claim 12 or 13. 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 12 to 14, characterized by comprising:

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