JP2013067063A - Device for thermoforming and forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermoforming device that can continuously carry out thermoforming to release mold rapidly, and efficiently by rapidly heating a forming body, or allocating the forming body in a cooling stroke while rapidly heating, and especially carrying out heat treatment at a high temperature more than a preheated sheet temperature before forming, in a process from forming to demolding of the thermal forming, and to provide a forming method.SOLUTION: In a thermoforming device of a thermoplastic resin sheet that performs pressure forming by a heating plate of the resin sheet, the heating plate used is composed by (1) heating compressed gas or introducing heated compressed gas, and while sending out this gas to the compressed air space from a plurality of holes prepared at the one surface in the compressed air box, and (2) absorbing the sent out gas to the compressed air space from a plurality of holes prepared separately in the same surface of the heating plate and discharging it to the outside.

Description

  The present invention relates to a method for producing a thermoformed product using a thermoplastic resin sheet or film, and relates to heating and / or cooling a shaped body during thermoforming at high speed, and further to a crystalline thermoplastic resin. In the process of thermoforming, the heat treatment at a temperature higher than the preheating temperature of the sheet is performed, and regarding the high-speed and efficient production of thermoformed products with high mechanical properties such as heat resistance and transparency, the crystalline resin It relates to performing this thermoforming using a stretched sheet.

The thermoforming method is a method in which a preheated thermoplastic resin sheet or film is formed on a mold by pressing or evacuation and then released. Usually, the shaped body is cooled in a low-temperature mold. Mold is released. As the mold material, a material such as aluminum or zinc alloy that is lightweight and has good workability and good thermal conductivity is used, and is often continuously formed by natural heat dissipation. However, in particular, if it is desired to adjust the temperature, the jacket provided inside the mold is cooled through a heat medium. On the other hand, cheap and easy-to-process materials such as wood and plastic may be used, but these are not durable and difficult to control temperature, causing problems such as heat accumulation, making them suitable for continuous mass production. However, its use is limited to sample trial production or small-scale production on a single-wafer molding machine.
And as a special molding method, when you want to heat or cool the shaped body arbitrarily during the molding cycle, change the heating medium in the middle of the heating medium passed through the jacket, or adjust the temperature of the shaped body separately It is performed to move to the mold. However, with such a method, a molded product that has been subjected to a desired heat treatment cannot be produced continuously at high speed and efficiently.

As a specific thermoforming method that requires special heating or cooling, (1) Japanese Examined Patent Publication No. 56-7855 is a method of thermoforming a polyester sheet by uniaxially stretching and heat-shrinking the sheet, Although a method of heat setting by using hot air at the time of molding is disclosed, the heat treatment takes a very long time and is not practical. In addition, (2) Japanese Patent Publication No. 5-45412 discloses a method of performing thermoforming and heat treatment using a sheet biaxially stretched under specific conditions and thermally contracted. Here, a method of transferring to a heating type, a heating method using hot air, hot water, infrared rays, etc. has been proposed, but it is not specifically described, and even if these are simply executed, there is no effect. And, if at all, it is not a fast, efficient and practical method. (3) Japanese Patent Publication No. 60-031651 also shows that a specific stretched polyester sheet is thermoformed and heat treated, and it is shown that it is molded with a heated mold, but the mold or molded product is cooled and separated. There is no mention of typing. However, for heat treatment molding of such materials, it is desirable to cool the molded body to at least a temperature lower than the heat treatment temperature and release the mold. However, if this is done by a known method, the mold itself is electrically heated. And a method of cooling in advance by passing water through a mold jacket immediately after molding, or a method of alternately passing a high temperature heat medium and a low temperature heat medium through the mold manifold. However, such a method cannot perform continuous molding at high speed. Also, (4) Patent 2532730 shows a method in which a non-stretched crystalline PET sheet is molded with a heated female mold, transferred to a low-temperature female mold, cooled, and released. At that time, deformation of the molded product, displacement, and generation of wrinkles become problems, and it is necessary to create a special dedicated molding apparatus capable of such operations.
In addition, (5) Japanese Patent Publication No. 7-102608 shows a method of forming with a high-temperature female mold, taking it into a low-temperature male mold fitted thereto, cooling it, and releasing the mold. It may be said that the method is the same as (4), and deformation and wrinkling of the molding become a problem as well, and it is difficult to apply to a molded product having an offset or undercut. In addition to these examples, in the so-called CPET molding as in (4) and (5), when molding is performed with a high-temperature mold from the beginning, the molding material does not slip on the mold surface, resulting in uneven patterns such as waves and irregularities. In order to avoid this problem, there is known a process in which a low-temperature mold is first molded and then transferred to a high-temperature mold, but this is also complicated.
In addition, the disclosure of (6) Japanese Patent No. 4044876 relates to thermoforming of a resin material in which sag (hanging of the sheet during heating) is likely to be a problem during sheet preheating. In such a material, a material sheet is usually used as a porous heating plate. After adsorbing for a short time, it is shaped away from it. In the case of this method, it is intended to avoid scratches at the time of adsorption of the hot plate, and the sheet is heated while supporting the sheet with the pressure of weak heated air, and then additional preheating is performed with the air passed through the hot plate. However, it does not require heat treatment at a temperature equal to or higher than the preheating temperature after shaping, nor does it require active cooling and mold release, and there is no suggestion to do this. In addition, since the stretched sheet formed by the apparatus of the present invention causes a shrinkage effect on preheating, if the sheet is fixed and this is done, it becomes a tension state and no sag problem occurs, and the working mechanism of the reference is not required.
(7) The method disclosed in Japanese Patent No. 4057487 relates to thermoforming of a crystalline resin, and a sheet preheated in contact with a heating plate is compressed and shaped with hot air passing through the heating plate and a molding die. Then, cooling air jetting means prepared separately is carried in and cooled, but this heating plate is adjusted to an appropriate temperature for sheet preheating, and heated air is supplied from behind to produce heated and compressed air. In this case, the heated gas is cooled in a conduit passing through the hot plate, and a very high temperature gas must be passed through the heat treatment, in which case the hot plate temperature is localized and non-uniform, and the material sheet is Local overheating tends to hinder good molding. In addition, the disclosed cooling means makes a wide area uniform. It cannot be cooled efficiently. Also, heat from the high temperature gas is easily dissipated into the mold, and the sheet cannot be easily heated to a high temperature in a short time, and high speed molding cannot be performed.
(8) The inventor of the present invention (hereinafter referred to as the present inventor) has filed at least eight prior applications related to the present invention. These will be introduced and explained as appropriate in the relevant parts of the text.

Japanese Patent Publication No. 56-7855 Japanese Patent Publication No. 5-45412 Japanese Patent Publication No. 60-031651 Japanese Patent No. 2532730 Japanese Examined Patent Publication No. 7-102608 Japanese Patent No. 4044876 Japanese Patent No. 4057487

  The present invention has been made in view of such problems of the prior art. Its main, and if necessary, can be cooled at high speed, and heat forming at a high temperature above the preheated sheet temperature before shaping can be performed continuously at high speed and efficiently. A thermoforming apparatus capable of obtaining a molded product is provided.

(1) In a thermoforming apparatus that performs compressed air molding using a heating plate of a resin sheet, as a heating plate, 1) heated compressed gas or introduced heated compressed gas, and compressed air from a plurality of holes provided on one side 2) Thermoplastic using a structure in which the gas sent to the compressed air space is absorbed in a plurality of holes separately provided on the same surface of the heating plate and discharged to the outside simultaneously. Resin sheet molding equipment.
In the present invention, “shaping” and “shaping process” indicate a part of the operations in the molding process, and the “shaped body” is the molding before release in a state of being held in the mold. Product. In addition, compressed air forming indicates a forming method including a compressed air process, and compressed air forming indicates a method of the forming process in the entire forming process. Note that compressed air means applying a gas pressure.

(2) The molding according to (1) above, wherein the heating plate has heating temperature adjusting means and is configured to preheat by adsorbing or pressing a resin sheet on the surface of the heating plate. A device is provided.

(3) Cooling means for injecting the cooling medium is arranged around the mold, and after the heating plate is separated from the mold, the cooling means is advanced with respect to the upper part of the mold, or the molding is performed. The molding apparatus according to any one of (1) and (2) above, wherein the mold is advanced to the lower part of the cooling means to cool the shaped body.

(4) The above cooling means (1) to (3) are characterized in that the cooling means comprises a cooling gas injection nozzle and a passage for rectifying the injected gas and exhausting it in the lateral direction. A molding apparatus according to any one of the above is provided.
In addition, the passage here may be partitioned by a solid object, or may be formed by fluid injection different from cooling injection.
In addition, it is preferable that the cooling means is provided with means for sucking exhaust gas passing through the passage and promoting exhaust gas.

(5) From the above (1) to (4), wherein a molding die is used in which at least a molding surface is formed of a material having a thermal permeability (kJ / m2s1 / 2K) of 0.01 to 15. ) Is provided.
The definition of the molding surface here excludes a coating agent for lubrication, mold release, etc., paint or plating of 50 μm or less applied to the molding surface.
As a specific configuration of this mold, it may be composed of the above material as a single unit, but 1) it is in close contact with the surface layer by a surface layer made of the predetermined material and a material having a higher heat permeability than that of the surface layer. It is preferable that the back layer is provided, and 2) it is preferable that the heating means is provided in close contact with the entire surface behind the surface layer, or the heating means is provided on the back body.
In this case, the heat permeability of the surface layer forming material is preferably 10 or less, and more preferably 5 or less.
In addition, it is preferable to use what comprised the surface layer for shaping | molding and the means which heat-heats this surface layer from the back regularly and uniformly as said shaping | molding die.

(6) A resin sheet molding method using the molding apparatus according to any one of (1) to (5) above, wherein the resin sheet is preheated, shaped, and at a temperature higher than the preheat temperature of the sheet. A method for forming a thermoplastic resin sheet comprising a heat treatment step for heat treatment and a cooling step is provided.

Thermoforming using the molding apparatus of the present invention has the following effects.
1) The apparatus of the present invention is a process at which the resin sheet is heat-treated at a temperature substantially exceeding the preheating temperature of the resin sheet in the process of preheating and releasing, and then cooled and released at a very high speed. It can be executed continuously, efficiently and stably.
2) In particular, the use of the heating plate in the configuration of the present invention facilitates the continuation and control of high-temperature gas injection. As a result, a) a strong and uniform heating temperature of the shaped body can be achieved, and the heat treatment time can be shortened. b) Since a strong heating temperature can be raised, the temperature setting of the mold can be lowered and the cooling time can be shortened. c) Since the heating temperature can be increased strongly, the design flexibility of the mold configuration is increased, and a durable and inexpensive mold can be manufactured.
3) By using the specific molding die as described above, molding with heating and cooling of the shaped body can be performed efficiently at high speed. And the object of the molding material which can be applied can be expanded and the production which saved energy consumption can be performed.
4) With a wide range of resins, it became possible to manufacture various molded products that were easily heat-treated.
Specific applications include: a) molding involving heat setting of a stretched sheet of a crystalline resin such as PET, b) molding involving crystallization of a crystalline resin sheet such as a crystal nucleating agent-added PET (CPET), or In addition, c) heat treatment molding can be proposed in which the residual stress distortion associated with SPPF molding (solid phase high pressure molding) of polypropylene is relaxed.
In particular, stretched PET can efficiently produce a thermoformed product having excellent mechanical strength such as heat resistance, transparency, and rigidity. Further, a material-saving molded product can be obtained by utilizing rigidity.

It is sectional drawing which shows the principal part of the structural example of the shaping | molding apparatus of this invention. It is sectional drawing which shows a well-known heating plate. It is sectional drawing which shows another well-known heating plate. It is sectional drawing which shows the detail of the example of a heating plate used for the shaping | molding apparatus structure of this invention. It is a top view of the heating plate shown in FIG. 4 used for the apparatus structure of this invention. It is sectional drawing which shows the example of a special structure of the shaping | molding apparatus of this invention. It is sectional drawing which shows the example of the cooling means which comprises the shaping | molding apparatus of this invention. It is sectional drawing which shows the example of the shaping | molding die of the shaping | molding apparatus of this invention.

<Overall configuration of molding apparatus>
The molding apparatus of the present invention constitutes a vacuum molding machine, a pressure molding machine or a vacuum / pressure molding machine which is a thermoforming machine. In the case of a pneumatic molding machine or the like that does not have a vacuum shaping function, it is preferable to add a mechanism for sucking and fixing the shaped body to the mold at least in the cooling step. In the molding method using the apparatus of the present invention, the preheating of the resin sheet, which is a molding material, is usually performed by a direct heating method in contact with a heating plate. However, as a special method, an indirect heating method using a heating oven or the like may be used.
The heating plate used in the apparatus configuration of the present invention 1) heats compressed gas or introduces heated compressed gas and sends it to a compressed air space through a plurality of holes provided on one side, and 2) sends it to this compressed air space. The formed gas is configured to be absorbed from a plurality of holes separately provided on the same surface of the heating plate and discharged to the outside. By adopting such a configuration, it is possible to heat or cool the shaped body by continuing the flow of the delivery gas, and it is possible to raise the temperature particularly efficiently.
In addition, although a heating plate is utilized for compressed air shaping and vacuum compressed air shaping as a shaping means, you may utilize a vacuum shaping as a shaping means. In the case of vacuum shaping, it suffices to perform compressed air with a heating plate after vacuum shaping, and the compressed air in this case is used for heating and heating the shaped body by jetting high temperature gas. Details of the heating plate will be described in the section <About heating plate>.
As an example of the device configuration, the heating plate is fixed to the top plate of the press machine, a forming die is fixed to the bottom plate directly below, and at least one of the top plate and the bottom plate is movable up and down to form heating plate means and forming Enables mold separation and separation.
Then, cooling means for injecting the cooling medium is arranged around the mold, and after the heating plate is separated from the mold, the cooling means is advanced with respect to the upper part of the mold holding the shaped body. Alternatively, the shaping mold is advanced to the lower part of the cooling means so that the cooling process of the shaped body can be performed. As a special aspect of the apparatus configuration of the present invention, no special cooling means is provided, and one of the two types of porous groups of the heating plate is used for jetting the cooling medium. You can also.
The resin sheet for molding is preheated, shaped, heat treated, cooled by the approaching cooling means, and released. After completion of molding, the cooling means or mold is returned to the initial position.
In the configuration of the present invention, it is necessary to be able to set conditions that allow heat treatment of the shaped body, which is a) a method using a high-temperature gas delivered toward the shaped body, and b) to the shaped body. C) a method using infrared rays emitted toward the surface, and c) a method using a heating temperature-controlled mold. In the present invention, the heat treatment temperature rise may be performed only by the method a) or may be performed together with the method b) or c). A) will be described in detail in the section <About heating plate>. As for b), the heating plate surface is configured to increase the infrared radiation efficiency, and can be implemented as a special mode described later. The mold for c) will be described in detail in <Column for mold>.

A configuration example of the molding apparatus is shown in FIG. In this example, the mold configuration 60 is arranged on the bottom plate of the press, the heating plate 20 is fixed to the top plate of the press, and the cooling means 40 is arranged in the vicinity of the mold so as to be horizontally movable. Reference numeral 100 denotes a resin sheet of a molding material. The press, the preheating means, and the hot compressed gas generator are omitted from the figure. The heating plate 20 in this figure is composed of a low-temperature air supply / exhaust main body (air supply function is not essential) 21, a high-temperature air supply main body 31, and a contact preheating surface (gas delivery surface) 26. Adjusted to temperature.
The simplest operation setting using this configuration is to preheat the resin sheet with the contact preheating surface (gas delivery surface) 26 set to the preheating temperature, and then send the hot gas through the 35 heat-insulating air feed pipe, This is an operation for increasing the temperature of the heat treatment. At this time, the temperature of the heat treatment can be efficiently increased continuously by taking in the gas in the compressed air space through the gas feed / discharge hole 25 and exhausting it outside.
As another operation setting, first, a low-temperature compressed gas is sent out from the gas feed / discharge hole 25 to perform low-temperature compressed-air shaping, and then the gas in the compressed-air space is taken in through this 25 and exhausted to the outside while 35 feeds. The temperature of the heat treatment can also be increased by sending a hot compressed gas through the trachea to the compressed air space.
This heating plate has a high degree of freedom in operation, and various other conditions can be set.
In this figure, valves and the like are omitted, but each air supply or exhaust can be performed by controlling an arbitrary amount at an arbitrary time. As the mold configuration 60 and the rejecting means 40, any of those described later can be used. Details of the heating plate will be described in the section <About heating plate>.

It should be noted that the movement of the heating plate means or the mold does not necessarily have to be vertically moved up and down, and may be arbitrarily separated from each other by joining from an oblique direction, or may be separated and joined by a specific track. Good. Note that the positional relationship between the shaping means and the molding die is relative, and raising the shaping means is synonymous with lowering the molding die, and the molding die may be lowered. The shaping means may be inverted on the mold below. Further, as a unique aspect, the press machine may be rolled over, and a heavy mold or the like can be opened and closed easily and used as a preferred method. Both are included in the present invention.
Instead of moving the cooling means to the upper part of the mold as described above, the mold may be moved to the lower part of the cooling means. In that case, the shaping | molding die containing a shaping body may be moved, and the press machine holding the heating plate and the shaping | molding die may be moved.
The thermoforming machine constituting the present invention may be a single-wafer forming machine that forms short material sheets one by one, or may be a continuous molding machine that sequentially forms long material sheets. However, the latter is particularly preferable, and the characteristics of the present invention are exhibited to enable high-speed and efficient repetitive molding.

Such a configuration of the present invention is based on the prior application, the Japanese Patent Application No. 2010-118555, the Japanese Patent Application No. 2010-118490, the Japanese Patent Application No. 2010-118489, the Japanese Patent Application No. 2010-118562, the Japanese Patent Application No. 2011-41294, the inventor as the inventor. Japanese Patent Application No. 2011-165067, Japanese Patent Application No. 2011-165068, Japanese Patent Application No. 2011-165069
Etc. were further improved to improve product quality, improve productivity, and expand application fields. And it is made in order to show those concrete forms.

<About the heating plate>
A known and commonly used heating plate is usually configured to contact a resin sheet directly and preheat it, and at that position, a cold compressed gas is introduced from the outside and compressed air is formed. It is not the structure which heats an air body to specific temperature. A typical example is as shown in FIG. 2, and the heating plate 20 includes a low-temperature feed / exhaust body 21, a heater 22, a compressed gas introduction pipe 23, a distribution gas passage 24, a gas feed / discharge hole 25, and contact preheating. It consists of a surface (also a gas feed / discharge surface) 26. The heater 22 is provided for adjusting the temperature of the contact preheating surface (also serving as a gas delivery surface) 26. Such a heating plate is used for adsorbing and preheating a resin sheet against a material in which heat sag (sagging) or the like becomes a problem due to indirect heating of an oven or the like. This heating plate is not usually an internal mechanism with a gas heating purpose, and low-temperature pressure forming that does not reach the preheating temperature is performed. In addition, a temperature other than the preheating proper temperature cannot be set, and even if a high temperature gas is introduced, inconvenience such as disproportionation of the preheating surface temperature occurs, and arbitrary high temperature pressure forming cannot be performed.
FIG. 3 shows a known and slightly different one from the above. This is disclosed in Japanese Patent No. 4057487, in which the resin sheet is directly preheated with a heating plate, and pressure forming is performed with a high-temperature compressed gas introduced from the outside. Here, the heating plate 20 includes a low-temperature gas supply main body 21, a heater 22, and a compressed gas introduction pipe 2.
3, a gas distribution passage 24, a gas delivery hole 25, and a gas delivery surface (contact preheating surface) 26. In this heating plate, the resin sheet is preheated in contact with the gas delivery surface (contact preheating surface) 26, and is then pressure-formed by high-temperature compressed gas introduced from the outside.
In this heating plate, the temperature becomes non-uniform in the vicinity of the delivery hole due to the high-temperature compressed gas introduced from the outside, leading to preheating unevenness in the resin sheet, and if the hole is enlarged to avoid this, an opening mark is added. . Above all, there is a problem that a closed space by compressed air is born and the air supply is stopped, and the temperature of the shaped body cannot be continuously and effectively increased.
On the other hand, the heating plate used in the present invention 1) introduces or generates heated compressed gas, distributes it through a plurality of holes provided on one side, and sends it out in parallel. The gas is accommodated inside and discharged from the plurality of holes on the one surface. By doing so, the temperature of the heat treatment can be efficiently and continuously increased by sending a high-temperature gas while exhausting the gas from the compressed air space to the outside, and various operation settings and conditions can be set. Can be.

Specific examples of the heating plate constituting the present invention are shown in FIGS. These drawings show the heating plate shown as a part of FIG. 1 in more detail. FIG. 4 is a sectional view, and FIG. 5 is a plan view showing the lower surface of the sectional view. Here, the heating plate 20 includes a low-temperature air supply / exhaust main body (the air supply function may not be used) 21 and a high-temperature compressed gas air supply main body 31, and the heater 22 has a contact preheating surface (gas supply / discharge surface) 26. The heater 32 supplementarily heats the hot compressed gas introduced by heating the air supply body 31 at a high temperature. The high-temperature compressed gas introduced to the gas distribution space 34 through the high-temperature compressed gas introduction pipe 33 passes through the air supply heat insulating pipe 35 and is sent out from the gas delivery hole 38 to perform pressure forming and heat treatment temperature rise of the resin sheet 100. . The high-temperature gas used for pressure forming and heat treatment temperature rise is accommodated in the gas passage space 24 through a gas feed / discharge hole (also a vacuum suction hole) 25 and used as an exhaust pipe (introducing pipe for normal temperature compressed gas). Exist) 23 is exhausted to the outside. The air supply heat insulating pipe 35 is formed of a heat insulating and heat resistant material such as ceramics, and further provided with a heat insulating space 35b to eliminate the temperature influence on the contact preheating surface (gas supply / discharge surface) 26 as much as possible. The heat insulating material 27 and the heat insulating material 37 are for eliminating temperature effects on or from other portions, respectively.
In addition, such a heating plate can also be used by changing the mode of details as described below.
1) A compressed gas at normal temperature may be introduced from the outside, and the compressed gas may be heated to a high temperature inside the high-temperature air supply main body 31 and can be used as a preferable configuration. In that case, the capacity of the heater may be increased and the internal space may be subdivided to increase the contact area with the air.
2) A normal temperature compressed gas is introduced into the low-temperature air supply / exhaust body 21 and supplied from the gas supply / exhaust hole 25 to perform low-temperature compressed air shaping, and then exhausted via the gas supply / discharge hole 25 as described above. While performing the above process, the high temperature gas may be sent from the air supply hole 38 to heat-treat the shaped body. It can be preferably used for molding a heat sensitive material such as a thin material.
3) After shaping by the heating plate in the above figure and heat treatment, the operation valve (not shown in the figure) connected to the exhaust pipe 23 is switched, non-heated compressed gas is introduced, and ejected from the feed / discharge hole 25 The cooling process of the shaped body can also be performed. In this case, the heating plate may be lifted slightly for exhausting from the compressed air space, but the operation valve (not shown in the figure) connected to the conduit 33 is switched so that the air can be exhausted by suction from the gas delivery hole 38. It is preferable to provide a suction / exhaust device connected to the conduit 33. Even if the introduced gas may be slightly heated by the exhaust body 21 adjusted to the preheating temperature, it is sufficient in a field where strong cooling is not required.
4) In the heating plate of the above figure, the intake air from the hole group 25 of the low-temperature air supply / exhaust body 21 is collected in the passage 24 and exhausted to the side, but the intake air from the hole group 25 is sent by a narrow tube or a collecting tube. You may comprise so that it can penetrate to the back of the gas 31 and can exhaust, and the structure of this invention is not impaired.
5) In the heating plate of the above figure, the basic structure is left as it is, and the functions of the upper high-temperature air supply body 31 and the lower low-temperature air supply / exhaust body 21 are exchanged. The high-temperature air supply main body 31 may be used. The heated gas may be introduced from the outside, or may be generated inside the heating plate body. In this case, another device for reducing the temperature influence of the heated gas temperature on the preheated surface of the resin sheet is possible. Even if the heated gas temperature is limited to a temperature that does not greatly differ from the preheated surface temperature, the compressed air by the gas at that temperature has a certain convenience effect. Furthermore, if this heating plate is not used for preheating the resin sheet, the gas temperature can be set freely. This specific method will be described later.
6) The heating plate of the present invention is preheated by bringing a resin sheet into contact therewith, but this may not be performed and only preheating may be left to other means such as indirect heating. This is a special aspect and will be described in detail in the next section.

FIG. 6 shows a specific example of the above 6). The heating plate 20 has almost the same structure as that shown in FIG. Further, the molding die configuration 60 is obtained by housing the molding die shown in FIG. The storage box 67 has a height higher than the upper surface of the mold. This figure shows a state in which the resin sheet 100 is preheated in another place and is transported to this position, and further, evacuation from the mold side is performed prior to the pressure forming.
If a structure and operation like this figure are performed, compressed air shaping and heat processing can be performed, without contacting the principal part of a resin sheet with the contact preheating surface of a heating plate. Accordingly, the delivery surface of the heating plate may be at any temperature, and there is no problem with the temperature of the delivery gas, and a high-temperature gas having an arbitrary temperature can be generated and delivered internally.
Note that there is no problem even if the functions of the high-temperature air supply main body 31 and the low-temperature air supply / exhaust main body 21 are exchanged as in 5) above.

In addition, it is desirable that the temperature of the heated gas that is introduced for heat treatment temperature rise and is sent out by compressed air is much higher than the preheating temperature of the resin sheet. Specifically, the temperature of the introduced compressed gas is 250 to 600 ° C. It is desirable that For example, a hot plate preheating of about 90 to 100 ° C. is appropriate for preheating the stretched PET sheet, whereas the gas temperature from the nozzle 35 is preferably 250 to 500 ° C. Since the heat capacity of the gas is small, the amount of heat dissipates to the mold through the shaped body, so if the temperature of the injection gas is below this temperature, the temperature cannot be raised quickly, and it easily reaches the 150 to 180 ° C required for heat setting. do not do.
In addition, as the high-temperature compressed gas, air, nitrogen, carbon dioxide or the like compressed and heated by another apparatus is used. In particular, dry superheated steam containing water can be preferably used.

<About cooling means>
The cooling means of the present invention resides in the periphery of the mold, has a size and shape that covers substantially the entire upper surface of the mold or group of molds, and proceeds with respect to the upper part of the mold after the heating plate is lifted and separated. Then, the shaped body may be cooled and retreated. Any cooling means that can cool the shaped body by injecting a cooling heat medium can be used.
For example, as disclosed in Japanese Patent No. 4057487, a structure in which a large number of holes are provided in the box and the cooling gas introduced into the box is ejected can be used.
However, with the known cooling means, it has been difficult to uniformly and strongly cool a large area in a short time by gas injection in a narrow space. For this reason, it is preferable that the cooling means includes a cooling gas injection nozzle and a passage that rectifies the injected gas and exhausts it in the lateral direction. In addition, the passage here may be partitioned by a solid object, or may be formed by fluid injection different from cooling injection.
In addition, it is preferable that the cooling means is provided with means for sucking exhaust gas passing through the passage and promoting exhaust gas.

A specific example of the cooling means will be described with reference to FIG. In the cooling means 40 of this example, the compressed gas is introduced from the introduction path 42 and is injected from the nozzles 43 to cool the shaped body 110 and reflect it. The reflected gas is guided by the airflow guide surface 44, guided to the vertical passage 45, and further exhausted through the horizontal passage 46.
Even in this configuration, uniform and efficient cooling can be performed. However, if a nozzle that injects a strong straight air flow from one end of the horizontal passage to the inside or from the center to the outside is arranged, the above reflected gas is sucked from the vertical passage 45 to promote exhaust. can do. This injection nozzle is one of means for promoting exhaust. As another method, for example, a vacuum pump or a vacuum blower may be used for exhaust.
Note that the cooling medium used in the present invention is not limited to this example, and a volatile liquid such as water or alcohol, or a compressed gas (in some cases, a liquid) such as air, nitrogen or carbon dioxide is used alone or in combination. Can be used. In the case of a volatile liquid, it may be sprayed alone or may be sprayed into a gas before jetting. The cooling gas may be at a normal temperature, but a cooled gas can be preferably used, and a gas jet in which dry ice particle mass is submerged and cooled, or a gas jet in which dry ice powder particles are mixed is also preferable.
In addition, as another special aspect of the cooling means used in the present invention, it is preferable to have a configuration provided with means for spraying volatile liquid in addition to the gas injection means. By spraying the volatile liquid, it is possible to effectively cool by the specific heat of the liquid and the latent heat of evaporation.

Here, a supplementary description will be given of the passage that rectifies the jet gas and exhausts it in the side surface direction.
After being injected from a large number of injection nozzles in a large area and reflected by the shaped body surface, it collides with the subsequent injection gas, or closes the gas passage in other parts, preventing uniform and effective cooling. Therefore, it is useful to create an exhaust passage that rectifies the injected gas and exhausts it in the lateral direction. This passage can be formed by an object that guides or defends the reflected airflow, or it can be formed by a strong linear jet of gas flow. More specifically, 1) a method of creating a passage that draws behind the nozzle tip and escapes in the lateral direction, 2) a method of drawing into a horizontal passage that is substantially the same as or higher than the nozzle tip, and 3) horizontal separately from the cooling injection. There is a method of creating a powerful gas jet flow in the direction and drawing the reflected air flow to escape. The last 3) method does not necessarily require a section passage by an object. For example, if this is performed downstream of the cooling jet, a passage is substantially formed.

  The apparatus of the present invention using the cooling means as described above has the following effects. 1) Powerful cooling is possible, the mold can be set at a high temperature, and as a result, the degree of freedom in designing the mold configuration that can be used increases, and a low-cost mold can also be used. In addition, the molding materials that can be applied are widened, and the use of products is widened, and it is possible to produce inexpensive and high-performance products. 2) Powerful cooling is possible and the cooling time can be shortened. 3) Uniform cooling is possible, and not only the accuracy of the product and the efficiency of good products are improved, but also the cooling time can be shortened as a result.

<About molds>
The mold used as the apparatus constituent element of the present invention is not particularly limited as long as it includes necessary elements for known thermoforming such as a vacuum exhaust hole.
However, it is preferable to use a mold having at least a molding surface formed of a material having a thermal permeability (kJ / m2s1 / 2K) of 0.01 to 15 as a molding die used as an apparatus component of the present invention.
Examples of materials having a thermal permeability within this range include plastics, ceramics, and a small number of selected metal materials. These include aluminum materials and zinc alloys that are commonly used as thermoforming molds. The value is smaller than that of the material. Examples of materials having a preferred range of heat permeability can also be selected from Table 1. However, the notation is shown for reference to general substances or objects, and what can be used is not limited to these.
The thermal permeation rate and the significance of the numerical limitation will be described later in the section “Supplemental explanation about the contents of the present invention”.
In addition, the mold shown as a desirable aspect for the configuration of the present invention is a prior application in which the present inventor is an inventor, Japanese Patent Application Nos. 2010-118555, 2010-118490, 2010-118489, Japanese Patent Application No. 2010-118562, and This is disclosed in Japanese Patent Application No. 2001-065069.

As a further special aspect of the mold used as the apparatus component of the present invention, it is composed of a surface layer having the predetermined heat permeability and means for constantly and uniformly heating and controlling the surface layer from behind. It is preferable to use those prepared.
As a more specific and preferable method for this purpose, 1) a method in which a back layer close to the surface layer is provided by a material having a thermal permeability higher than that of the surface layer, and the back layer is heated and temperature-controlled, and 2) the surface layer There can be mentioned a method in which a heating means is provided in close contact with the substantially entire surface behind.
In this case, the heat permeability of the surface layer forming material is preferably 10 or less, and more preferably 5 or less. Further, the thickness of the surface layer is required to be 0.04 mm or more, preferably 0.06 mm or more, and more preferably 0.1 mm or more. The thickness is preferably 30 mm or less, more preferably 10 mm or less, and even more preferably 5 mm or less.

In the case of the above 1), it is necessary to make the thermal permeability of the back layer larger than that of the surface layer and to add a heating temperature adjusting means to the back layer. This heating means may be a known method, may be provided in the back layer, or may be provided outside. The surface layer is constantly heated by the conduction heat from the back layer.
The heat permeability of the back layer is preferably 3 or more, more preferably 6 or more, and even more preferably 10 or more. The thermal permeability of the back layer is preferably 2 times or more, and more preferably 10 times or more than that of the surface layer.
Note that the thickness of the back layer is not limited, and is not limited to a certain thickness or shape. Further, this layer is not limited to a single material layer, and may be an arbitrary multilayer.
FIG. 8 shows an example of the structure 1). The mold 60 includes a surface layer 61 and a back layer 62, 63 is a vacuum exhaust hole, 64 is an exhaust passage, and 65 is a heat medium passage for temperature control. With the configuration shown in this figure, for example, an epoxy resin layer (thermal permeability 0.67) of 0.5 mm is formed on the back layer of aluminum material A5052 (thermal permeability 17.4), and the back layer and the surface layer are passed through. Molds produced by exposing fine thermocouples on the molding surface have high performance. In addition, temperature control means, such as this heat-medium channel | path, are not provided here, You may make it provide arbitrary heating means for the fixing plate which fixes a shaping | molding die. The mold configuration shown in FIG. 1 is the latter.

The “molding die in which at least the molding surface is formed of the material having the above-mentioned heat permeability” used as a preferable component of the present invention has the following typical aspects, and has the following effects. is there.
a) A back body having a high heat permeability is provided behind the surface layer having the predetermined low heat permeability, and temperature control means is attached to the back body. This mold is most preferable because the temperature behavior of the surface layer can be controlled through the back body.
b) A back layer having a very low heat permeability is provided behind a surface layer having a predetermined moderate or relatively low heat permeability. In this mold, the temperature of the surface layer forms a specific temperature profile by repeated heating and cooling of the shaped body.
c) A temperature control means provided directly on the entire surface behind the surface layer having the predetermined low heat permeability.
d) The surface layer itself having the predetermined low heat permeability can self-heat.
Such a mold in which at least the molding surface is formed of a material having the above-described heat permeability, that is, a relatively low material compared to the most commonly used mold material, has the following effects.
B) The thermal diffusion to the deep part of the mold is reduced, and heating and cooling of the shaped body by gas blow having a small heat capacity is facilitated.
B) The temperature control of the surface layer from the back is supported, the heating and cooling burden due to the gas blow having a small heat capacity is reduced, and the molding cycle can be shortened by controlling in a balanced manner.
C) Uniform temperature unevenness generated and accumulated by repeated heating and cooling gas blow, uniform molded product, and shorten molding cycle.

<About molding method>
Using the apparatus of the present invention described above, a method for molding a thermoplastic resin sheet comprising a resin sheet preheating step, a shaping step, a heat treatment step for heat treatment at a temperature higher than the preheating step, and a cooling step can be performed. it can. Moreover, these processes can be advanced at high speed, and efficient continuous molding can be performed using a long molding material resin sheet.
In the preheating process, a long resin sheet is guided and stopped under the heating plate that is heated and adjusted to the preheating temperature, and the heating plate and the mold are moved close to each other to sandwich the heated sheet. Preheating is performed while vacuum-adsorbing from the plate side or air-pressing from the mold side. In the subsequent shaping step, pressure shaping with air discharged from the heating plate and / or vacuum shaping by vacuum suction from the mold side are instantaneously performed on the temperature-controlled mold. In the subsequent heat treatment step, the temperature of the shaped body is raised above the preheating temperature on the surface of the high-temperature mold and / or by the high-temperature gas released from the heating plate. In the cooling step next to this, the heating plate is raised, the cooling means is inserted between the opened heating plate and the mold, and the cooling medium is injected to cool and release the shaped body. In order to prevent deformation of the shaped body, it is necessary to fix the shaped body by evacuating the molding die at least through the cooling process, and it is desirable to do this through each process after shaping. .
In addition, in this apparatus, the temperature raising heat processing by the said high temperature compressed gas can also be performed following the pressure air shaping by a low temperature gas. This method is suitable when the resin sheet is thin and too sensitive to heat.
In addition, in this apparatus, following the vacuum shaping, the temperature increasing heat treatment using the high-temperature compressed gas can also be performed. Similar to the above, this method is also suitable when the resin sheet is thin and too sensitive to heat.

The apparatus setting or the condition setting in the molding as described above can be roughly described in three patterns. When looking at the change in the surface temperature (T) of the mold and the internal temperature (S) of the mold, a sine curve-like continuous molding cycle can be drawn. As an example, consider the case of using a mold consisting of a surface layer and a back layer as described above. The back layer temperature is S, the mold surface temperature is T, and the maximum temperature is Tt and the minimum temperature Tb.
Pattern A is a pattern in which S is adjusted to a constant temperature between Tt and Tb of the surface temperature cycle. In this case, Tt is a temperature reached by high-temperature gas or infrared irradiation, and Tb is a temperature reached by the cooling means. Direct temperature control of the back layer may or may not be performed. If the molding is continued continuously for a long time in a state where heat does not escape so much from the back side, the back layer temperature S settles at Tt and Tb of the surface temperature cycle. In this case, if the thermal permeability of the back layer is not so large, S is not linear in time in the vicinity of the surface layer, but draws a small temperature cycle following the surface layer. It is desirable to positively and arbitrarily adjust the temperature of the back layer, and the heating means and the cooling means can be set to the optimum shortest time depending on the temperature.
Pattern B is a pattern for adjusting S to a constant temperature equal to or lower than Tb. In this case, Tb is reached mainly by heat transfer from the back layer, that is, the temperature of S. The cooling means is not essential, but if used, the cycle can be shortened. Tt is reached by the heating means.
Pattern C is a pattern for adjusting S to a constant temperature equal to or higher than Tt. In this case, Tt is reached mainly by heat transfer from the back layer, that is, the temperature of S. Therefore, the heating temperature control of the back layer is essential. The heating means is not essential, but the cycle can be shortened if used. Tb is reached by the cooling means.

Normal thermoforming is performed through the process of preheating, shaping, cooling and releasing the resin sheet. On the other hand, the present invention is characterized in that a heat treatment at a temperature higher than that at the time of shaping of the resin sheet is performed from shaping to cooling, and this can be carried out continuously at high speed.
The method of the present invention makes it possible to produce various molded products that are easily heat-treated with a wide range of resins. Specific applications include: a) molding involving heat setting of a stretched sheet of a crystalline resin such as PET, b) molding involving crystallization of a crystalline resin sheet such as a crystal nucleating agent-added PET (CPET), or In addition, c) heat treatment molding can be proposed in which the residual stress distortion associated with SPPF molding (solid phase high pressure molding) of polypropylene is relaxed.
In particular, stretched PET can efficiently produce a thermoformed product having excellent mechanical strength such as heat resistance, transparency, and rigidity. Further, a material-saving molded product can be obtained by utilizing rigidity.
(Supplementary explanation about the contents of the present invention)

(1) <About heat penetration rate>
The thermal permeation rate (b value) used as the specified value of the present invention is a characteristic value of an object related to the amount of heat moving through the interface and the contacting object, and is obtained by the following equation.
b = (λρC) 1/2 (1)
λ; thermal conductivity (Js-1m-1K-1)
ρ; density (kgm-3)
C; Specific heat (Jkg-1K-1)
An object having a small b value flows only a small amount of heat to the interface and does not give a large temperature change to the counterpart object, and is greatly influenced by the counterpart object near the interface. Therefore, when the material having a small b value is used as the mold surface material, the heat from the shaped body is not diffused, so that the shaped body can be easily heated and cooled by the high-temperature gas and the cooling gas. However, since the heat of the back layer is not easily transferred to the surface layer surface (interface with the shaped body), the surface temperature is highly uniform, and the surface layer thickness is reduced for fast and stable condition setting. Or by increasing this b value to some extent, it can be optimized in accordance with the molding material.
In addition, as a reference example of the b value, for example, the aluminum material is about 17 to 23, the iron material is about 13 to 16, the copper is about 34, the non-rust steel (SUS306) is 8.0, and many synthetic resins are 0.0. About 2 to 0.8, many ceramics fall between 1 and 20.
Table 1 illustrates the b values of some materials. The b value also shows a slightly different value depending on the measurement temperature, but in the present application, strictly, it is defined by a measurement value of 20 ° C. However, in the case of a composite material with a material having no linearity in a change between 20 ° C. and 200 ° C., for example, a heat storage agent accompanied by a phase change, an average value of 100 ° C. and 150 ° C. should be adopted. To do. It should be noted that even if the same material is used, if the shape changes to a foam or a porous body, this value will change greatly.

(2) <Significance of numerical limitation of mold configuration>
When a surface material having a large thermal permeability b value is used as the surface layer of the mold, heat is easily dispersed from the shaped body to the back, so that heated air or cooling air having a relatively small heat capacity is used. Then, it becomes impossible to heat and cool the shaped body easily, and when this value is a material exceeding 10, it is impossible to efficiently perform the heat treatment. This value is preferably small, but if it is smaller than 0.01, there is no material that can withstand use such as strength.
The above mold has a structure of two or more layers, the back layer of the surface layer is controlled to a constant temperature, and the molding surface temperature of the surface layer that changes in temperature by the heating gas and the cooling gas through the shaped body is set to a desired level. Quick return to the reference temperature.
In this case, if the thickness of the surface layer exceeds 30 mm, the control of the back layer takes too much time to reach a steady state in response to the surface temperature, which is not practically effective. Moreover, when this thickness is less than 0.03 mm, the influence of the temperature of a back layer is received greatly, and the effect which accelerates | stimulates temperature rising / falling of a quick shaping body loses. For example, in a known molding method, even if a mold such as a fluorine resin is temporarily formed on the mold for lubrication and release, the coating thickness is as thin as 30 μm or less. There is no need to do this, and there is a difficulty, and no device that can achieve the effects of the present invention has been produced.
As described above, a single material may be used, but in this case, there may or may not be direct temperature control on the mold, and in either case, the desired surface temperature may be stabilized to some extent. If the time is taken, the desired molding is possible. However, in this case, it is preferable that the heat permeation rate b value (kJ / m2s1 / 2K) is made of a single material having a temperature of 0.01 to 3 without a heating temperature control mechanism, and it is 3 or more. Those composed of a single material are more preferably those having a heating temperature control mechanism.
In addition, it is desirable that the above-mentioned mold has a fine hole that enables vacuum forming or evacuation at the time of forming, and is housed in the above-mentioned mold storing box so that it can be evacuated.

(3) <Temperature measurement of shaped body>
In the apparatus of the present invention, it is important to measure the change in the surface temperature of the mold or the interface temperature between the mold and the shaped body or the temperature change of the shaped body by some method. Specifically, for example, an extremely delicate measurement probe, for example, a thermocouple tip having a wire diameter of about 0.1 mm is projected on the molding surface of the mold, and this can be measured. As another method, there is a method of measuring the shaped body from the opposite surface without contact with an infrared thermometer. However, there are points to note.
In the patterns A and C, the temperature of the S-line is actively controlled to control the temperature of the mold itself. However, depending on the distance from the molding surface or the distance from the heat source, the molding cycle is repeated with a temperature gradient. It is also a value that stabilizes at.
When strictly considering the heat treatment temperature or mold release temperature of the shaping material, it should be noted that these temperatures are considerably different from the surface temperature or interface temperature shown here. This is because when heating and cooling are performed in units of seconds or less, a large temperature gradient occurs in the thickness direction of the shaped body. Also, temperature measurement from the back of the shaped body with infrared rays or the like does not accurately represent the material temperature. In the present invention, it is expressed by the surface temperature (interface temperature), but there is a difference from this temperature and it is necessary to consider it as a relative value.

The stretched PET sheet was molded with heat treatment using the apparatus configuration of FIG. 1 using the heating plate shown in FIGS. 4 and 5 and the cooling means shown in FIG.
1) Molding material: A 2.3 times uniaxially stretched sheet of homopolyethylene terephthalate resin (but not heat-set) and a non-heat-fixed product having a thickness of 0.23 mm were used.
2) Molding equipment
Molding machine: A single-wafer vacuum / pressure forming machine having a pressure capacity of 10 tons was used.
4 and 5, with a preheated surface made of carbon steel and having an effective dimension of 330 × 550 mm, with a gas feed hole 25 having a diameter of 1 φmm at each intersection of a grid with a spacing of 30 mm. A gas delivery hole 38 for high-temperature gas was provided in the arrangement shown in FIG. The low-temperature air supply / exhaust main body 21 and the gas supply / discharge hole 25 have the functions of suction and fixing during preheating of the resin sheet, pressurized air shaping by the low-temperature gas, and exhaust from the compressed air space. The high-temperature air supply body 31 and the gas delivery hole 38 have a function of delivering the high-temperature compressed gas to the compressed air space.
The air supply function of the low-temperature air supply / exhaust main body 21 is used for compressed air shaping, but this is not essential, and if this is not used, the high temperature air supply body 31 performs pressure air shaping and heat treatment temperature rise.
Cooling means: the structure shown in FIG. 7, that is, a method in which a reflected flow of the injected cooling gas is sucked from a passage 45 provided between the injection nozzles 43 and exhausted in the horizontal direction, with an effective size of 330 × 550 mm. I used something.
Molding die: Surface layer / back layer system shown by 60 in FIG. 8, with aluminum A 5052 as the back layer, and a zirconia (b value is 2.8) 0.3 mm surface layer formed by thermal spray coating What was let to use was used.
The molded product is a round dish shape with a diameter of 90 mm and a depth of 30 mm, and 15 molds with an outer dimension of 110 mm square are fixed to the fixing plate of the heater inclusion, and placed in a storage box with an inner dimension of 332 x 552 mm. I stored it. The upper surface of the mold was 5 mm lower than the side wall of the storage box, and a 1 mm gap was provided from the side wall.
Temperature measurement: The tip of the thin wire thermocouple was exposed on the molding surface, and the molding surface temperature and the interface temperature of the shaped body could be measured. Similarly, a thin wire thermocouple was placed through the back of the heating plate so that the pressure temperature could be measured.
3) Molding method and molding conditions;
Preheating of the resin sheet; preheating by adsorbing to a heating plate set at 95 ° C. for 2 seconds.
Mold surface preheating temperature; 160 ° C
Air introduced into the heating plate; about 330 ° C, original pressure 0.4 MPa
Vacuum pressure shaping; 1.5 seconds, pneumatic pressure 0.4 MPa
The high temperature air supply body 31 was used.
Heat treatment temperature rise: 2.5 seconds Exhaust from the low-temperature air supply / exhaust body 21 was activated, and high-temperature gas was continuously supplied from the high-temperature air supply body 31. The pressure temperature reached 288 ° C.
Heat treatment temperature (interface temperature); 187 ° C.
The surface temperature instantaneously dropped to about 160 ° C. or lower during shaping, but the temperature was raised to this temperature.
Cooling means operating time: 5 seconds
The surface (interface) temperature dropped to about 140 ° C. during mold release.
4) Comparative test: When the shaping and heat treatment by the air supply from the high-temperature air supply body 31 was performed without exhausting from the low-temperature air supply / exhaust body 21 under the above conditions, the interface temperature reached temperature was about 165 ° C. Prolonging the air pressure time had no effect. Further, it was deformed at the time of mold release and did not become a molded product having a good shape. This condition setting means that the heat treatment effect is insufficient.
5) Molding result;
The obtained molded product had a good shape and transparency. A test of immersion in silicon oil having a heat resistance of 140 ° C. for 2 minutes was performed, and there was no deformation or noticeable shrinkage, and the heat resistance was excellent. It was found that the heating plate used was easy to heat-treat with a high-temperature gas.
It was found that efficient heat treatment effect is difficult to achieve under the conditions of the comparative test, that is, the condition setting possible with a known heating plate.

In the configuration of Example 1, the stretched PET sheet was molded by heat treatment by the operation method of FIG. Here, the preheating of the resin sheet was performed in a heating oven prepared separately.
1) Molding material: the same as in Example 1 was used.
2) Molding apparatus: the same as in Example 1 was used. However, a separately prepared heating oven was used for preheating the resin sheet.
3) Molding method and molding conditions;
Mold surface preheating temperature; 160 ° C
Air introduced into the heating plate; about 330 ° C, original pressure 0.4 MPa
Preheating of resin sheet: The resin sheet was preheated and moved for 9 seconds in a preheating oven at 550 ° C. and placed on the upper part of the mold. The sheet preheating temperature is 95 ° C.
Prior to vacuum shaping; 0.3 seconds Immediately before the heating plate was lowered, the vacuum shaping by the mold was activated in advance.
Pneumatic shaping; 1.5 seconds, Pneumatic pressure 0.4 MPa
Simultaneously with the lowering of the heating plate, the hot gas was fed from the hot gas feed body 31.
Heat treatment temperature rise: 2.5 seconds or less In the same manner as in Example 1, molding was performed in the same manner.
4) Molding result;
The obtained molded product had a good shape and was as high as heat resistant Example 1. Since there was no contact with the heating plate, there was also an advantage that many exhaust hole traces, air supply hole traces, surface scratch marks, etc. were not copied.
It was found that even with such a unique configuration, it is easy to raise the temperature of the heat treatment with a high-temperature gas.
This configuration can also have the following advantages.
1) Since it is not related to preheating, any temperature can be set, greatly expanding the possible conditions.
2) Since it does not involve preheating, the possible structural configuration can be greatly expanded.

In the apparatus configuration shown in Example 1, the molding die and the operating conditions were changed, and molding with heat treatment of the CPET sheet was performed. Here, no cooling means was used.
1) Molding material: CPET sheet for molding containing a crystal nucleating agent (Toyobo, thickness 0.5 mm)
2) Molding method and molding conditions;
Preheating of the resin sheet: The resin sheet was preheated and moved in a preheating oven set at 550 ° C. for 18 seconds and placed on the upper part of the mold. The sheet preheating temperature is about 100 ° C.
Mold temperature: The temperature of the back body was adjusted to 100 ° C. with a heat transfer oil. The mold surface temperature at this time was about 95 ° C.
Air introduced into the heating plate; approx. 250 ° C, original pressure 0.4 MPa
The air supply body 31 was adjusted to substantially the same temperature as the introduced gas.
Vacuum pressure forming and heat treatment: 12 seconds, pressure pressure 0.2 MPa
Lower the heating plate, press the preheated resin sheet against the upper part of the mold storage box wall, operate the exhaust from the low temperature air supply / exhaust body 21, and continue the supply of high temperature gas from the high temperature air supply body 31. This process was carried out. The preheated resin sheet did not come into contact with the preheated surface of the heating plate due to the heat sag. The compressed air temperature was about 200 ° C.
Heat treatment temperature (interface temperature); 166 ° C.,
Cooling means operating time: 0 seconds
The mold was released immediately after shaping without operating the cooling means.
After mold release, the mold surface temperature dropped to the original set temperature in a short time, and the next molding became possible.
3) Reference test;
In order to shorten the heat treatment temperature increase time, when the mold surface temperature was set to 160 ° C. close to the heat treatment temperature, thermoforming was performed, and unevenness of unevenness occurred in the molded product. In order to obtain a clean molded product with CPET, it was necessary to shape with a low-temperature mold at least about the preheating temperature and then heat up and heat treatment.
4) Molding result;
A molded product that was precisely and satisfactorily molded was obtained. The fact that the heat treatment has been performed effectively is also understood from the fact that the molded body could be released from the mold without contraction and deformation even though the shaped body was still at a high temperature of 166 ° C. or higher.
In the conventional thermoforming of CPET, a complicated and time-consuming method such as transferring a molded product molded with a low-temperature mold to a high-temperature mold and performing a heat treatment is adopted, but this method is simple and short. It has been found that it is possible to perform molding with heat treatment at a temperature higher than the preheating temperature over time.

The following is possible for thermoforming according to the present invention.
(1) A molding process involving heat treatment and cooling mold release for heating the shaped body above the preheating temperature for shaping can be carried out at a very high speed, continuously, efficiently and stably.
(2) A specific application that requires such heat treatment is thermoforming that involves heat setting of a stretched crystalline resin sheet. Examples of the material include stretched sheets such as PLA, thermoplastic resin such as PET, crystalline resin such as polypropylene, polyamide, and PEEK.
(3) Among them, in particular, by performing thermoforming that performs the above heat treatment using a stretched PET sheet, it is possible to efficiently produce thermoformed products having excellent mechanical strength such as heat resistance, transparency, and rigidity. Can do. Further, it is possible to obtain a material-saving molded product using rigidity, and to meet the social needs of resource saving.
(4) A crystalline resin sheet that has not been subjected to stretching treatment, for example, can be used for molding involving crystallization of PET (CPET) to which a crystal nucleating agent is added, and this can be performed at a higher speed than before. it can.
(5) In addition, expecting a new method, etc. that can be applied to SPPF molding of polypropylene (solid phase high pressure molding) to solve the disadvantages of this molding method (reducing residual stress distortion and improving heat-resistant dimensional stability). Can do.
(6) Molding with heat treatment can be performed precisely, uniformly, without variation, at high speed and with energy saving, and the improvement in strength and rigidity due to orientation and crystallization has been converted to a material with reduced thickness, It is possible to contribute to the social needs for resource conservation.

20 Heating plate 21 Low temperature air supply / exhaust body (air supply function is not essential)
22 Heating heater
23 Exhaust pipe (also introduced as compressed gas introduction pipe)
24 Gas branch passage 25 Gas feed / discharge hole (also vacuum suction hole)
26 Contact preheating surface (gas feed / discharge surface)
27 Heat insulation material 29 Heat insulation material 31 High-temperature air supply body
32 Heating heater
33 High-temperature compressed gas introduction pipe
34 Compressed gas distribution space 35 Air supply heat insulation pipe 35b Heat insulation space 37 Heat insulation material 38 Gas delivery hole 39 Pressure air space 40 Cooling means
41 Cooling body (flat plate)
42 Compressed gas introduction path
43 Cooling gas injection nozzle
44 Airflow guide surface
45 Vertical exhaust passage
46 Horizontal exhaust passage
60 Mold 61 Surface layer
62 Back layer (back body)
63 Vacuum exhaust hole
64 Exhaust passage 65 Heating medium passage
66 Mold collection plate 67 Mold storage box
67b Storage box notch 68 Cartridge heater
100 Thermoplastic resin sheet (resin sheet)
A compressed gas
A 'exhaust V evacuation HA high temperature compressed gas

(6) The above-mentioned (1), wherein a molding die is used in which at least a molding surface is formed of a material having a thermal permeability (kJ / m ² s ^1/2 K) of 0.01 to 15. ) To (5). The thermoforming apparatus according to any one of (5) is provided.

<About molds>
The mold used as the apparatus constituent element of the present invention is not particularly limited as long as it includes necessary elements for known thermoforming such as a vacuum exhaust hole.
However, as a special aspect of the mold used as the apparatus component of the present invention, at least a molding surface is formed of a material having a thermal permeability (kJ / m ² s ^1/2 K) of 0.01 to 15. It is preferable to use the same.
Examples of materials having a thermal permeability within this range include plastics, ceramics, and a small number of selected metal materials. These include aluminum materials and zinc alloys that are commonly used as thermoforming molds. The value is smaller than that of the material. Examples of materials having a preferred range of heat permeability can also be selected from Table 1. However, the notation is shown for reference to general substances or objects, and what can be used is not limited to these.
The thermal permeation rate and the significance of the numerical limitation will be described later in the section “Supplemental explanation about the contents of the present invention”.
In addition, the mold shown as a desirable aspect for the configuration of the present invention is a prior application in which the inventor is the inventor, Japanese Patent Application Nos. 2010-118555, 2010-118490,
This is disclosed in any one of Japanese Patent Application Nos. 2010-118489, 2010-118562 and 2001-0665069.

(1) <About heat penetration rate>
The thermal permeation rate (b value) used as the specified value of the present invention is a characteristic value of an object related to the amount of heat moving through the interface and the contacting object, and is obtained by the following equation.
b = (λρC) ^1/2 (1)
λ; thermal conductivity (J s ⁻¹ m ⁻¹ K ⁻¹ )
ρ; density (kg m ⁻³ )
C; Specific heat (J kg ⁻¹ K ⁻¹ )
An object having a small b value flows only a small amount of heat to the interface and does not give a large temperature change to the counterpart object, and is greatly influenced by the counterpart object near the interface. Therefore, when the material having a small b value is used as the mold surface material, the heat from the shaped body is not diffused, so that the shaped body can be easily heated and cooled by the high-temperature gas and the cooling gas. However, since the heat of the back layer is not easily transferred to the surface layer surface (interface with the shaped body), the surface temperature is highly uniform, and the surface layer thickness is reduced for fast and stable condition setting. Or by increasing this b value to some extent, it can be optimized in accordance with the molding material.
In addition, as a reference example of the b value, for example, the aluminum material is about 17 to 23, the iron material is about 13 to 16, the copper is about 34, the non-rust steel (SUS306) is 8.0, and many synthetic resins are 0.0. About 2 to 0.8, many ceramics fall between 1 and 20.
Table 1 illustrates the b values of some materials. The b value also shows a slightly different value depending on the measurement temperature, but in the present application, strictly, it is defined by a measurement value of 20 ° C. However, in the case of a composite material with a material having no linearity in a change between 20 ° C. and 200 ° C., for example, a heat storage agent accompanied by a phase change, an average value of 100 ° C. and 150 ° C. should be adopted. To do.
It should be noted that even if the same material is used, if the shape changes to a foam or a porous body, this value will change greatly.

Claims (6)

In a thermoforming apparatus that performs compressed air molding using a heated plate of a resin sheet, as a heated plate, 1) heating compressed gas or introducing heated compressed gas, and sending this to a compressed air space from a plurality of holes provided on one side However, 2) a thermoplastic resin sheet that is configured to absorb the gas sent to the compressed air space from a plurality of holes separately provided on the same surface of the heating plate and discharge it to the outside in parallel. Molding equipment. The molding apparatus according to claim 1, wherein the heating plate has heating temperature adjusting means and is configured to preheat by adsorbing or pressing a resin sheet on the surface of the heating plate. Cooling means for spraying the cooling medium is arranged around the mold, and after the heating plate is separated from the mold, the cooling means is advanced with respect to the upper part of the mold, or the mold is The molding apparatus according to claim 1, wherein the shaped body is cooled by being advanced to a lower portion of the cooling means. 4. The cooling means according to claim 1, wherein the cooling means comprises a cooling gas injection nozzle and a passage for rectifying the injected gas and exhausting it in the lateral direction. Molding equipment. The mold according to any one of claims 1 to 4, wherein a mold having at least a molding surface formed of a material having a thermal permeability (kJ / m2s1 / 2K) of 0.01 to 15 is used. Molding equipment. A resin sheet molding method using the molding apparatus according to any one of claims 1 to 5, wherein the resin sheet is preheated, shaped, and heat treated at a temperature higher than the preheat temperature of the sheet; And the molding method of a thermoplastic resin sheet provided with a cooling process.