JP2013107301A - Thermoforming device, and forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermoforming device and a forming method capable of performing such a thermoforming that a shaping material body is quickly heated or the shaping material body is quickly heated and is subjected to cooling process and, in particular, the shaping material body is subjected to heat treatment at a temperature of a preheated sheet temperature before shaping or higher, then the shaping material body is shaped and released from molds, these processes being efficiently and continuously carried out at a high speed.SOLUTION: The thermoforming device of a thermoplastic resin sheet which performs pressure gas forming of the resin sheet, a gas compression unit having such mechanisms that at least cooling compressed gas is sent from a gas supply opening to an upper part of a forming mold and the sent gas is discharged to the outside through a suction opening on the upper part of the forming mold, such that (1) at least the gas supply from the gas supply opening is performed by distributing and sending the gas from a distribution space disposed behind the plurality of gas supply openings or (2) the gas discharge is performed by collecting the gas in a gas collection space disposed behind the plurality of gas collection openings, wherein the mechanisms are integrated with each other.

Description

  The present invention relates to a method for producing a thermoformed article 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 released in a cooled state with a low-temperature mold. Typed. As a mold material, a material such as aluminum or zinc alloy that is lightweight and has good workability and good thermal conductivity is used, and it 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 molding of so-called CPET as in (4) and (5), if molding is performed with a high-temperature mold from the beginning, the molding material does not slide smoothly on the mold surface, and thus unevenness such as waves and unevenness is generated. There is also a problem that a pattern is likely to appear. To avoid this problem, a process of forming with a low temperature mold and then shifting to a high temperature mold is known, 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 11 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 purpose is to heat the shaped body at high speed and cool it as necessary at high speed in the process from thermoforming to mold release, especially heat treatment at a temperature higher than the preheating sheet temperature before shaping. It is an object of the present invention to provide a thermoforming apparatus that can perform thermoforming for releasing at high speed and efficiently and obtain a molded product in a uniform and good state.

(1) In a thermoforming apparatus that performs pressure air molding of a resin sheet, as a pressure air box, at least a cooling compressed gas is sent from an air supply opening to the upper part of the mold, and the sent gas passes through an intake opening at the upper part of the mold. A mechanism for exhausting to the outside, and at least 1) gas delivery from the air supply openings is performed by distributing from a distribution space provided behind the plurality of air supply openings, or 2) the exhaust is made plural The present invention provides a molding apparatus for a thermoplastic resin sheet that uses a gas collecting space that is provided behind the air collecting opening and that is integrated with the mechanism.
The compressed air box does not have to have a box-shaped compressed air space as it is, and may be a structure that can form a substantial compressed air space without going through contact with the resin sheet. .
In the present invention, molding indicates the entire molding process from preheating to mold release, and compressed air molding indicates a molding method including a compressed air process. In addition, compressed air is to give gas pressure, compressed air shaping indicates a shaping process by compressed air in the whole molding process, and the “shaped body” is held in the mold before release. The molded product shall be indicated.

(2) The conduits leading to the air supply opening or the intake opening are respectively provided through the air collection space or the distribution space or between the spaces. The molding apparatus according to 1) is provided.

(3) The molding apparatus according to (1) or (2) above, wherein either the air supply opening or the air intake opening is provided at a position closer to the molding die surface. To do.

(4) In order for the compressed air box to change the gas to be supplied in the middle of one molding process to a different temperature and send it out, the mechanism for sending the gas from the air supply opening exhausts the gas from the middle Any one of (1) to (3) above, wherein the mechanism for sucking and exhausting air from the intake opening is configured to function as a mechanism for sending a gas at a different temperature from the middle. Is provided.

(5) 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 25. ) To (4).
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.
The heat permeability of the surface layer forming material is preferably 20 or less, more preferably 15 or less, and still more preferably 10 or less.
This mold may be composed of the above-mentioned material as a single unit, but it may be a back layer or a back body formed of any material with the above material as a surface layer.
In addition, when providing a surface layer, it is preferable to provide a temperature control means closely to the whole back surface.

(6) The mold is characterized by comprising a surface layer made of a material having a thermal permeability (b value) of 20 or less and a back body made of a material having a thermal permeability (b value) larger than that of the surface layer. The molding apparatus according to any one of (1) to (5) is provided.
In such a mold, it is preferable that a heating means is provided in close contact with the entire surface behind the surface layer, or a heating means is provided on the back body.

(7) As means for heating the shaped body held in the mold, 1) means for sending heated gas from the compressed air box, or 2) at least one means for heating and using the mold is used. The molding apparatus according to any one of the above (1) to (6) is provided.

(8) A resin sheet molding method using the molding apparatus according to any one of (1) to (7) above, wherein the resin sheet is preheated, shaped, and heat treated at a temperature higher than the sheet preheat temperature. The present invention provides a method for forming a thermoplastic resin sheet comprising a heat treatment step and a cooling step.

(9) As a method for heat-treating the shaped body at a high temperature, at least one of 1) a method of sending heated gas from the compressed air box, or 2) a method of heating and using the holding mold is used. The molding method according to 8) 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) A thermoforming machine capable of normal pressure forming, particularly by using the above-described pressure forming box in the configuration of the present invention, and without adding special cooling means or a device for generating heated compressed gas, etc. It is possible to easily form the resin sheet by shaping and heat treatment. Further, it is possible to uniformly heat the large molding area and uniformly cool it. Further, since uniform heating and cooling can be performed, the molding cycle can be shortened.
3) It is not necessary to provide a cooling means separately, and it is not necessary to move the cooling means, so that the molding cycle can be shortened and high speed molding can be performed.
4) By using the 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.
5) It became possible to manufacture various molded products that were 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. d) Residual distortion is eliminated even by thermoforming of amorphous (amorphous) resin, and a product with high dimensional accuracy can be obtained.
6) In particular, stretched PET can efficiently produce a thermoformed product having excellent mechanical strength such as heat resistance, transparency, and rigidity, and can obtain a material-saving shaped product using rigidity. .

It is sectional drawing which shows the principal part of the molding apparatus structural example of this invention. It is a top view which shows the lower surface of the compressed air box of FIG. It is sectional drawing of a shaping | molding apparatus structure using a well-known compressed air box. It is sectional drawing which shows another example of the aspect of the compressed air box used for this invention. It is sectional drawing which shows another example of an aspect of the shaping | molding apparatus structure of this invention. It is sectional drawing which shows the shaping | molding die which comprises the shaping | molding apparatus of this invention.

<Overall configuration of molding apparatus>
The molding apparatus of the present invention constitutes a pressure forming machine or a vacuum / pressure forming machine that is a thermoforming machine. For the preheating of the resin sheet as the molding material, any known method such as indirect heating using a heating oven or direct heating in contact with a heating plate may be employed.
In a thermoforming apparatus that performs pressure forming of a resin sheet, as a compressed air box, at least cooling compressed gas is sent from the air supply opening to the upper part of the mold, and the sent gas is exhausted to the outside through the air intake opening at the upper part of the mold. Or at least 1) gas delivery from the air supply openings is performed by distributing from a distribution space provided behind the plurality of air supply openings, or 2) the exhaust air is collected from the plurality of air collections. This is performed by collecting air in an air collecting space provided behind the opening, and this is an integrated structure of the above mechanism.
In the compressed air box, it is preferable that a conduit reaching the air supply opening or the intake opening passes through the air collection space or the distribution space, or penetrates between the spaces.
In the above-described compressed air box, either the air supply opening or the air intake opening may be provided at a position closer to the mold surface, which is preferable.
As the compressed gas for cooling, a compressed gas having a temperature equal to or lower than the preheating temperature of the resin sheet is sent to the compressed air space. If only the cooling gas is sent out and the heating gas is not sent out, the temperature of the shaped body is increased by heat treatment using a mold whose surface temperature is adjusted to a temperature higher than the preheating temperature of the resin sheet. . A mode in which a high-temperature gas for heat treatment is sent in addition to the use of the compressed compressed gas will be described later.
The above-mentioned compressed air box is fixed to the top plate of the press machine, the mold is fixed to the bottom plate directly below it, and at least one of the top plate and the bottom plate is movable up and down so that the pressure box and mold are joined and separated. to enable.
The resin sheet for molding is preheated and brought into the upper part of the mold, sandwiched by the lowering of the compressed air box or the rising of the mold, shaped by air supply from the compressed air hox, heat treated by molding, Cooling is performed by supplying air from the compressed air hox, and the compressed air box and the mold are separated to release the shaped body. It should be noted that it is desirable to suck and fix the shaped body to the mold until release.
By adopting such a configuration, the shaped body is heated and heated from the surface of the molding die almost simultaneously with the compressed air shaping, and then the shaped body is effectively cooled by continuing to send the compressed gas. Can do.
In addition, the compressed gas used for compressed air can use arbitrary things as long as it is harmless to a human body, a molded object, etc., such as air, nitrogen, a carbon dioxide. Further, in order to enhance the cooling effect as necessary, moisture may be mixed into these gases, or fine droplets of volatile substances such as volatile substances such as alcohol may be mixed.
The specific shape, deformation mode, etc. of the above-mentioned compressed air box can be arbitrarily used after this and in the section <About compressed air box>, and the mold used can be arbitrarily used as long as it is used for thermoforming. The desirable mold will be described in detail in <Column for Mold>.

An example of the overall configuration is shown in FIG. In this example, a molding die configuration 60 is fixed on a press machine bottom plate, and a compressed air box 30 including an exhaust port (exhaust body) 21 and an air supply port (air supply body) 31 is fixed and arranged on a press machine top plate. is there. Reference numeral 100 denotes a resin sheet of a molding material. The molding machine itself, the press machine, the preheating means, the compressed gas generating device, etc. are omitted from this figure.
This figure shows a state in which the preheated resin sheet 100 has been introduced into the upper part of the mold 60. After this, the compressed air box 30 descends and pressure forming with compressed gas and heat treatment with a heated mold are performed. The temperature is raised successively, followed by cooling with compressed gas. Compressed gas is sent out from the delivery port 31. When the exhaust valve of the exhaust port 21 is opened at the same time as shaping or immediately after shaping, the gas in the compressed air space is renewed and the shaped body can be cooled efficiently. it can.
After the cooling process is finished, the compressed air box is raised and the shaped body is released.
The mold configuration 60 is a mold in which a surface layer 61 and a back layer (back body) 62 are fixed to an integrated plate 66 having a heating heat medium passage 65 and stored in a storage box 67. The surface layer 61 is made of a material having a low heat permeability, and the back layer 62 is made of a material having a high heat permeability.

It should be noted that the movement of the compressed air box 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 by being joined by a specific track. . 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.
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.

  The present invention is a prior application in which the inventor is the inventor, Japanese Patent Application No. 2010-118555, Japanese Patent Application No. 2010-118490, Japanese Patent Application No. 2010-118489, Japanese Patent Application No. 2010-118562, Japanese Patent Application No. 2011-41294, and Japanese Patent Application No. 2011-165067. , Japanese Patent Application No. 2011-165068, Japanese Patent Application No. 2011-165069, Japanese Patent Application No. 2011-206514, Japanese Patent Application No. 2011-206515, Japanese Patent Application No. 2011-206516, and improved the product quality of thermoforming with heat treatment, and productivity It was made to improve the application field and expand the application field. It is also intended to present a new and specific device form that embodies them. The device configuration of Japanese Patent Application No. 2011-206514 is very similar to that of the present invention on the drawing, but this device is provided with cooling means such as injection of cooling gas separately according to the necessity of the cooling means. It has a configuration to be added. On the other hand, according to the present invention, at least the cooling gas is delivered (injected), and when the heating gas needs to be delivered (injected), the same structure can also be used.

<About the compressed air box>
The concept of a well-known commonly used compressed air box is to sandwich a resin sheet and cover a mold or a group of molds, create a closed space between the resin sheet, and perform compressed air molding by sending compressed gas into this closed space. It is a tool. Usually, compressed air is performed by a normal temperature compressed gas.
In order to compare with the apparatus configuration of the present invention, an apparatus configuration in which a cooling means by a separate gas injection or the like is arranged outside the compressed air box considered in the above known knowledge, and this is moved after compressed air shaping. Is shown in FIG. The compressed air box includes an air supply port 31, a compressed gas introduction path 33, a distribution space 34, an air supply port 35, an air supply / exhaust surface 36, and a compressed air space (a space formed by the box) 39. As in the case of FIG. 1, the compressed air box descends, the resin sheet 100 that has been preheated and introduced is sandwiched, and compressed air shaping is performed with high-temperature compressed gas, and cooling such as gas injection that has entered after the pressurized air box has been raised Cooling can be performed by means 40 to release the mold.
However, such a compressed air box is not efficient because it requires time for moving the cooling means. A similar configuration in which a pressure plate is used instead of a compressed air box to perform compressed air shaping and the cooling means is moved during molding is also disclosed in Japanese Patent No. 4057487. However, such a cooling means reduces the total molding area. It cannot be cooled uniformly and quickly.

In contrast to the above, the compressed air box used in the configuration of the present invention (1) sends at least the cooling compressed gas from the air supply opening to the upper part of the mold, and sends the sent gas through the intake opening at the upper part of the mold. A mechanism for exhausting to the outside, and at least 1) gas delivery from the air supply openings is performed by distributing from a distribution space provided behind the plurality of air supply openings, or 2) the exhaust is made plural This is performed by collecting air in the air collecting space provided behind the air collecting opening, which is an integral structure of the mechanism.
And at least the normal temperature or the compressed gas below the preheating temperature of a resin sheet is sent out, so that the resin sheet can be shaped and the shaped body can be cooled effectively.
Further, it is preferable that the compressed air box is provided such that (2) the conduit leading to the air supply opening or the air intake opening passes through the air collection space or the distribution space, or passes between the spaces.
Further, the compressed air box may be (3) provided so that either the air supply opening or the air intake opening is located at a distance closer to the mold surface. The air supply opening and the air intake opening do not necessarily have to be formed on a flat surface, and it is preferable that cooling can be performed effectively or uniformly by providing a height difference.
Further, in the above-described compressed air box, (4) in order to change the gas to be supplied in the middle of the molding process to a different temperature and send it out, the mechanism for sending the gas from the air supply opening exhausts the gas from the middle. A mechanism that functions as a mechanism and sucks and exhausts air from the intake opening may function as a mechanism that sends a gas at a different temperature from the middle, and this can be suitably used.

A specific example of (1) including the above (2) will be described in detail with reference to FIG. 1 and FIG. FIG. 2 is a plan view of the lower surface of the compressed air box in FIG.
FIG. 1 shows a state in which the preheated resin sheet 100 is introduced into the upper part of the mold 60. After this, the compressed air box 30 descends and presses the periphery of the resin sheet 100 against the molding storage box 67. A closed compressed air space 39 is formed. The compressed gas introduced from the outside is sent out from the air supply opening 35 via the introduction path 33 and the distribution space 34, and is subjected to compressed air shaping. The temperature increasing heat treatment of the shaped body is performed by heat transfer from the mold 60 that is heated and held above the heat treatment temperature by the heat medium. When the exhaust operation valve 29 is opened at the same time as shaping or after a while, the gas in the compressed air space 39 is exhausted to the outside via the air collection pipe 28, the exhaust passage 23, etc. The compressed gas is delivered, and the shaped body can be effectively cooled.
It is also possible to use the upper stage as an air supply body and the lower stage as an exhaust body, with the structure of FIG. 1 almost unchanged.

Another example of the above (1) will be described with reference to FIG. This configuration does not include the configuration (2). The compressed air box 30 includes an exhaust port 21, an exhaust path 23, an air collection space 24, an intake opening 25, an operation valve 29, an air supply port 31, a compressed gas introduction path 33, a distribution space 34, an air supply opening 35, an air supply / exhaust. The surface 36, the compressed air space 39, and the operation valve 41 are configured.
In this configuration, the exhaust port 21 and the air supply port 31 are not in a relationship of upper and lower stages, and each has a comb shape, and each main part is nested in a plane. As in the case of FIG. 1, the gas introduced into the air supply port 31 is supplied to the compressed air space 39, and the supplied gas is collected into the exhaust port 21 and exhausted to the outside.
In addition, the section between the air supply port 31 and the exhaust port 21 in the figure may be eliminated, and both may be formed of an integral material, or a heat insulating material may be inserted between the two. In addition, if necessary, a heater may be attached to the air supply port 31 or the like so that the air supply port 31 can be heated, and the air supply gas temperature may be appropriately set.
Note that the functions of the air supply port 31 and the exhaust port 21 may be interchanged in the configuration of this figure, or gases having different temperatures and the like may be sent out sequentially from different ports. This is achieved by switching the operation valves 29 and 41. Easy to implement.

An example of the above (3) and (4) will be described with reference to FIG. The compressed air box 30 in this figure has an exhaust port 21, an exhaust path 23, an air collection space 24, an air collection pipe 28, an intake opening 25, an operation valve 29, an air supply port 31, a heater 32, a high temperature, as in FIG. It is composed of a compressed gas introduction path 33, a distribution space 34, an air supply opening 35, an air supply / exhaust surface 36, a heat insulating material 37, a compressed air space 39, and an operation valve 41. Here, the height of the inflow opening 25 at the tip of the air collecting tube 28 protrudes from the air supply / exhaust surface 36. This height is adapted to the depth of the depression of the mold. By doing so, the gas sent from the air supply opening 35 reaches the surface of the shaped body sufficiently, and an effective and uniform heat treatment temperature rise is achieved. it can. The heater 32 is for keeping or heating the introduced high-temperature gas. In the configuration of this figure, the operation valves 29 and 41 are switched during the molding cycle, and the exhaust port 21 is used as the air supply port. The air supply port 31 can be used as an exhaust port. In this case, if normal temperature compressed air is introduced into the exhaust port 21 and exhausted from the air supply port 31, the supplied air reaches the surface of the shaped body sufficiently and can be effectively cooled.
The inner surface of the air supply port 21 or its distribution space 34 may be formed of ceramics having a low heat permeability, which can reduce heat loss due to the cooling gas.
In this example, since the tip of the exhaust inflow pipe protrudes higher than the pressure box wall, the resin sheet is pierced when the pressure box is lowered. However, this phenomenon is not a problem at all if the vacuum shaping is preceded by the descent of the compressed air box.
In addition, such an aspect may be desirable because a portion including the air supply opening 35 may be formed individually or in a plurality of groups instead of the air collecting tube 28 and may be formed. Further, the structure shown in FIG. 5 may be left as it is, and the upper stage may be configured as an air supply port and the lower stage may be configured as an exhaust port.

Next, a special embodiment of the compressed air box will be described. The apparatus configuration of this aspect uses a structure that is a single plate and does not form a box shape as a compressed air box used in the present invention, and forms a box-shaped space, that is, a compressed air space, together with other members.
This example will be described with reference to FIG. The compressed air box 30 in this figure is composed of an air supply port 31 and an exhaust port 21, but unlike those shown so far in FIGS. It is a single plate shape with no part to be formed, and does not have a box shape. In the configuration shown in this figure, the mold is stored in a storage box having a side wall higher than that of the mold, and the pre-heated resin sheet is evacuated from the mold side, and then the compressed air box 30 is lowered, A space 39 is formed. Each subsequent process may be performed in the same manner as the compressed air box in FIG.
The compressed air box 30 in this figure is a compressed air box constituting the present invention although the space forming function as a box has been transferred to a part of the mold storage box.
In this case as well, the structure shown in FIG. 6 may be left as it is, and the upper stage may be configured as an air supply port and the lower stage may be configured as an exhaust port.

The above compressed air box may further have the following modes, and these modes can be preferably used.
1) In the middle of one molding cycle, the same gas supply body may be used to change the supply gas to a gas having a different temperature or the like. In the case of changing to a greatly different temperature, it is preferable to use a heat insulating material having a low heat permeability in at least the inside of the air supply body, and it is preferable to set the passage to an appropriate temperature between the two gas temperatures. With this configuration, the heat treatment temperature of the shaped body may be raised with a heated gas, and then cooled with a low temperature gas. The compressed air shaping may be performed with a heated gas or a low temperature gas.
2) The basic structure shown in each of the above drawings may be substantially unchanged, and the upper stage 21 may be configured as an air supply port and the lower stage 31 may be configured as an exhaust port.
3) It is preferable that the gas preheated in compressed air shaping can be used. The preheated compressed gas having a temperature equal to or lower than the predetermined temperature is supplied to perform the shaping step, and then the heat supply temperature is increased or the cooling step can be performed by supplying the gas at an appropriate predetermined temperature. By doing so, the preheated sheet can be shaped without cooling, and is particularly suitable for a stretched crystalline resin sheet material that is easily heat-set by excessive preheating. In order to supply the preheated gas, a heater may be provided in the corresponding air supply port, and the introduced compressed gas may be heated.
4) The resin sheet can be preheated by air supply from a compressed air box. That is, it is preferable to perform this in a configuration in which the resin sheet is heated immediately before shaping or during shaping and gas is gradually fed.
5) When supplying a high-temperature gas, it is possible to introduce a normal-temperature compressed gas and heat and supply it in the mechanism of the compressed air box. For example, it can be realized by making the internal air passage into a space having a large air contact area with a heated metal or the like, and passing the introduced gas therethrough.
6) It is also preferable to spray or spray a volatile liquid such as water or alcohol together with the delivery of the compressed gas for cooling the shaped body. In this case, a nozzle for spraying or spraying the shaped object from the inside of the compressed air box or the like may be provided.
6) The cooling gas is preferably at a temperature lower than room temperature, and may be cooled by immersing the compressed gas in a dry ice lump, or the dry ice powder may be mixed and jetted with gas, Or you may cool using the means of adiabatic expansion.
7) It is preferable that the exhaust from the compressed air box has no resistance, and it is preferable that the exhaust through the intake port is promoted by providing a suction means. As a specific example of such means, for example, a suction exhaust blower may be provided, or an aspirator mechanism using a strong straight jet flow may be used.

The above-described compressed air box is a further improvement of the one disclosed in Japanese Patent Application Nos. 2011-165067 and 2011-41294, the inventors of which are the inventors. Further, it supplements what is disclosed in Japanese Patent Application No. 2011-206514, and the empty means and the cooling means are made identical.
The compressed air box used in the configuration of the present invention has the following effects. 1) The gas can be sent out continuously as desired, and the process can proceed to the cooling process quickly, and the molding cycle can be shortened. 2) The entire molding surface can be cooled uniformly and efficiently, and a uniform and highly accurate molded product can be obtained. 3) The entire molding apparatus can be simply configured. 4) Powerful cooling can be performed. As a result, the design flexibility of the mold configuration that can be used can be greatly expanded, and a simple and low-cost mold can be used.

<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 the mold used as the apparatus component of the present invention, a mold having at least a molding surface formed of a material having a thermal permeability (kJ / m ² s ^1/2 K) of 0.01 to 25 is used. That is preferred.
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.

As a further special aspect of the mold used as the device component of the present invention,
It is preferable to use a surface layer having the above-mentioned predetermined heat permeability and a means for adjusting the surface temperature of the surface layer constantly and uniformly from the back.
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 20 or less, more preferably 15 or less, and still more preferably 10 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. 6 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, the mold made by forming an epoxy resin layer of 0.5 mm on the back layer of the aluminum material 5052 and exposing a fine thermocouple on the molding surface through the back layer and the surface layer is a high performance. It is. 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.

In the case of 2), the heating means is provided in close contact with substantially the entire back surface of the surface layer having the predetermined heat permeability. The structure of the surface layer in this case is the same as that in 1) above in terms of material and dimensions, and the desirable structure is also the same. The formation of the heating means is not limited to the following. For example, there is a method in which a) a planar heating layer is formed behind the surface layer, and b) a planar high heat transfer layer is formed to conduct heat from a specific position. There is no particular restriction on the presence, material, or shape of the back layer.
In the configuration of the above 2), the back layer 72 is not particularly limited as long as the surface layer or the layer of the heating unit can be held without hindering the function of the heating unit, and the shape of the surface layer can be maintained. It should be possible to fix it somewhere.

<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 above molding process, the resin sheet is preheated with a preheating oven or a heating plate, and then guided to the upper part of the mold, and the compressed air box or the mold is moved up and down to sandwich the resin sheet. It is performed by cooling and separating the shaped body by separating the compressed air box and the mold. At this time, the compressed air shaping is performed by sending compressed gas at normal temperature or a preheat suitable temperature of the resin sheet or a temperature lower than that, and the shaped body is heated from a mold that is heated and adjusted to a temperature higher than the preheat optimum temperature of the resin sheet. The shaped body is cooled by continuously sending compressed gas to the compressed air space. The continuous delivery of the compressed gas to the compressed air space is performed by starting the exhaust from the exhaust body while continuing the compressed air. Exhaust from the exhaust body can be started at an arbitrary time, may be exhausted from the time of shaping, may be started immediately after shaping, or may be started after a short time immediately after shaping. Also good. These optimum times vary depending on the mold used and the set temperature conditions.
In addition, said thermoforming may change the following concrete aspects, and can utilize it preferably. For example, 1) shaping may be performed by feeding a preheat temperature of a resin sheet or heated compressed gas close to this temperature, and then cooling may be performed by a gas at a lower temperature such as room temperature. Alternatively, 2) shaping may be performed while preheating the resin sheet while slowly feeding the preheat temperature of the resin sheet or heated compressed gas close to this temperature at the molding position, and 3) in the compressed air box It may be shaped while preheating the resin sheet with infrared irradiation means, so as to prevent deformation of the shaped body, it is necessary to fix the shaped body by vacuuming the mold until release. Is desirable.

The apparatus setting or the condition setting in the molding as described above can be roughly described in three patterns.
The molding process involving heat treatment can draw a sine curve-like continuous molding cycle when looking at changes in the surface temperature (T) of the mold and the internal temperature (S) of the mold. 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
Although it is not essential, if it is used, the cycle can be shortened. Tb is reached by the cooling means.
In the configuration of the molding apparatus of the present invention, the patterns C and A can be molded particularly efficiently.

Normal thermoforming is performed through the process of preheating, shaping, cooling and releasing the resin sheet. On the other hand, the molding method of the present invention is characterized by performing a heat treatment at a temperature higher than that at the time of shaping of the resin sheet between shaping and cooling, and is characterized by being able to be performed at high speed continuously. .
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 mold used in 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 ⁻¹ m ⁻¹ K ⁻¹ )
ρ; density (kgm ⁻³ )
C; Specific heat (Jkg ⁻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.

(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 permeability b value (kJ / m ² s ^1/2 K) is made of a single material having a temperature of 0.01 to 3 without a heating temperature adjustment mechanism. As for those composed of three or more single materials, those equipped with a heating temperature control mechanism can be used more preferably.
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.

With the apparatus configuration shown in FIGS. 1 and 2, the stretched PET sheet was molded with heat treatment.
1) Molding material: Homopolyethylene terephthalate resin 2.3 times uniaxially stretched sheet (however, not heat-set), thickness 0.23 mm was used.
2) Molding equipment
Molding machine: A single-wafer vacuum / pressure forming machine having a pressure capacity of 10 tons was used.
1 and 2 In the structure shown in FIGS. 1 and 2, a compressed air box composed of an air supply port 31 and an exhaust port 21 made of aluminum was mounted in a box body 67 made of aluminum and having an effective inner size of 330 × 550 mm. The gas feed surface 36 was provided with a high-temperature gas delivery port 35 having a diameter of 1 mm at every intersection of a grid lattice with an interval of 30 mm, and a gas collection tube 28 was provided in the arrangement shown in FIG. The exhaust port 21 and the air collecting pipe 28 have a function of exhausting from the compressed air space. The air supply port 31 and the delivery opening 35 have a function of delivering compressed gas to the compressed air space.
Molding die: Surface layer / back layer system 60 shown in FIG. 1, with aluminum A 5052 (b value 17.4) as the back layer, and PEEK resin (b value 0.35) 0.14 mm on it The surface layer was formed by a coating baking method.
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 a fixed plate of the heater's inner package and stored in a storage box with an inner dimension of 332 x 552 mm. It was. 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 to allow measurement of the molding surface temperature and the shaped body interface temperature.
3) Molding method and molding conditions;
Preheating of the resin sheet: The resin sheet was preheated and moved for 9 seconds in a preheating oven set at 550 ° C. and placed on the upper part of the mold. The sheet preheating temperature is 95 ° C.
Mold surface preheating temperature; 185 ° C
Air introduced into the compressed air box; approx. 30 ° C, original pressure 0.4 MPa
Vacuum pressure forming and heat treatment; 3.0 seconds, pressure pressure 0.4 MPa,
Exhaust from the exhaust main body 21 was activated and air was supplied from the air supply main body 31.
Heat treatment temperature (maximum temperature during shaping); 180 ° C,
The surface temperature instantaneously dropped to about 160 ° C during shaping,
It became this temperature.
Air cooling; 1.5 seconds, pneumatic pressure 0.1 MPa,
Exhaust from the exhaust port 21 was activated, and normal temperature gas was continuously supplied from the air supply port 31. At the time of mold release, the surface (interface) temperature again decreased to about 160 ° C.
4) Comparative test a) A test was conducted in which the exhaust from the exhaust port 21 was not performed under the above conditions, and only the air supply (compressed air) from the air supply port 31 was continued.
b) A test was conducted in which the exhaust from the exhaust port 21 was not performed under the above conditions, and the compressed air box was instantaneously raised about 2 mm to continue air supply from the air supply port 31.
5) Molding result;
The obtained molded product had a good shape and transparency. A test of immersion for 2 minutes in a silicon oil having a heat resistance of 140 ° C. was conducted, 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 high-temperature gas.
In the comparative test a), there was no cooling effect, and the product was contracted and deformed at the time of mold release, so that the molded product did not have a good shape. In comparison test b), it was found that the entire molding surface could not be cooled uniformly, and in particular, the shrinkage deformation due to insufficient cooling of the molded product particularly located inside was found.

In the apparatus configuration shown in Example 1, a partial change of the compressed air box and a used stretched PET sheet were changed to perform molding with heat treatment. Here, compressed air shaping was performed so as not to cool the preheating temperature of the resin sheet.
1) Molding material: A 2.7-fold uniaxially stretched sheet of homopolyethylene terephthalate resin (those not heat-fixed) having a thickness of 0.21 mm was used.
2) Molding device Molding machine: The same one as in Example 1 was used.
Air pressure box: A heater is attached to the air supply port 31 of FIG. 1, the air supply port is heated slightly, and a slightly heated compressed gas is introduced, so that the gas can be delivered at the same temperature as the resin sheet preheating optimum temperature. I did it.
Mold: The same mold as in Example 1 was used.
3) Molding method and molding conditions;
Preheating of resin sheet; 95 ° C
The same operation as in Example 1 was performed.
Preheating temperature on the mold surface; 190 ° C Gas delivered to the compressed air space; Pressure 0.4 MPa
The delivery port of the compressed air box was preheated to 95 ° C., and heated compressed gas at about 95 ° C. was introduced to deliver the compressed air.
2. Vacuum pressure forming and heat treatment; 0 seconds, pneumatic pressure 0.4 MPa,
This was carried out by supplying normal temperature compressed gas from the air supply port.
Heat treatment temperature (maximum temperature during shaping); 180 ° C,
The surface temperature instantaneously dropped to about 170 ° C. at the time of shaping, but soon rose to this temperature.
Cooling time: 4 seconds
Exhaust from the exhaust body 21 was activated and the same gas was continuously supplied from the air supply body 31. The surface (interface) temperature dropped to about 160 ° C. during mold release.
4) Comparative test;
(A) With the exhaust from the exhaust port 21 stopped, compressed air was supplied from the air supply body 31 by air supply. The airflow will stop immediately.
(B) Molding was performed in the same manner as in the above 3) except that the compressed air at normal temperature was introduced and sent out without operating the heater of the compressed air box.
(C) Molding was performed in the same manner as 3) above except that the preheating in the preheating oven was 10 seconds (about 106 ° C.).
5) Molding result;
In the molding performed under the condition 3), a good molded product was obtained as in Example 1. It shows that cooling is possible even at a gas temperature suitable for shaping.
The comparative test (a) shows that the molded product has been deformed and has not been cooled. In (b), it looked good, but the details were not well formed and the corners were rounded. In the case of a material having a large stretch ratio and poor moldability, it is indicated that it is better to shape the preheated sheet without cooling it with compressed air. Also in (c), the molded state of the details was similarly inferior. This also indicates that if the preheating is performed excessively in anticipation of cooling by gas pressure air at about room temperature, the heat setting of the stretched sheet proceeds and it is inconvenient for molding.

In the apparatus configuration shown in Example 1, the molding die and the operating conditions were changed, and the same stretched PET sheet as in Example 1 was molded with heat treatment.
1) Molding material: Homopolyethylene terephthalate resin 2.5 times uniaxially stretched sheet (however, not heat-set), thickness 0.22 mm was used.
2) Molding device;
Mold: The same shape and dimensions as those of Example 1 except that S45C (b value 16.1) is used as a steel material as the mold material. It was configured using.
3) Molding method and molding conditions;
Preheating of resin sheet; 95 ° C
The same operation as in Example 1 was performed.
Preheating temperature of mold surface; 195 ° C
Gas introduced into the pressure box; normal temperature, original pressure 0.4 MPa
Shaping, heat treatment, cooling; 5 seconds, pneumatic pressure 0.15 MPa,
While operating the exhaust from the exhaust main body 21, it was performed by supplying normal temperature compressed gas from the exhaust main body. A vacuum operation from the mold side was also performed from the time of shaping. Exhaust was done through a pressure control valve. Mold surface (interface) temperature: about 175 ° C. (average of differences depending on the site) This temperature was instantaneously reached during molding, and a substantially constant temperature was exhibited until release.
In this method, a clear boundary between the shaping, heat treatment, and cooling steps is not known.
4) Comparative test Under the above conditions, the exhaust from the exhaust body 21 was stopped and compressed air was used.
5) Molding result;
A good molded product was obtained. The molded product was resistant to hot water at about 100 ° C., and heat treatment was effective.
In the comparative test, the molded product contracted and deformed at the time of mold release, and a molded product having a good shape was not obtained. This indicates that cooling has not been performed by the time of mold release.
In this example, the same surface temperature is shown in the process of heat treatment and cooling. However, it can be considered that the temperature gradient in the thickness direction of the shaped body has a cooling effect and that good mold release is possible.

In the apparatus configuration shown in Example 1, the molding die and the operating conditions were changed, and molding with heat treatment of the stretched PET sheet was performed. The same molding material as in Example 3 was used.
1) Molding material: The same material as in Example 3 was used.
2) Molding device Molding machine: The same one as in Example 1 was used.
Compressed air box; the same as in Example 1 was used.
Molding die: of the surface layer / back layer system shown in 60 of FIG. 1 and the like, with aluminum A 5052 (b value 17.4) as the back layer, and SUS304 (b value 8.0) 5.0 mm What formed the surface layer was used. The shape, dimensions, number, etc. of the molded product were the same as those in Example 1, and the same fixed plate and storage box were used.
3) Molding method and molding conditions Preheating of resin sheet; 95 ° C
The same operation as in Example 1 was performed.
Preheating temperature of mold surface; 188 ° C
Gas introduced into the pressure box; normal temperature, original pressure 0.4 MPa
Shaping, heat treatment, cooling; 4 seconds, pneumatic pressure 0.15 MPa,
While exhaust from the exhaust port 21 was activated, air was sent from the air supply port at room temperature compressed gas. A vacuum operation from the mold side was also performed from the time of shaping. Exhaust was performed through a pressure control valve.
Mold surface (interface) temperature: about 171 ° C. (average of differences depending on parts)
This temperature was instantaneously at the time of shaping, and was almost constant until release.
In this method, a clear boundary between the shaping, heat treatment, and cooling steps is not known.
4) Comparative test: Exhaust from the exhaust port 21 was stopped under the above conditions, and compressed air was used.
5) Molding result A good molded product was obtained. The molded product was resistant to hot water at about 100 ° C., and heat treatment was effective.
In the comparative test, there was no cooling effect, shrinkage deformation at the time of mold release, and the molded product did not have a good shape.

In the apparatus configuration shown in FIG. 5, the same stretched PET sheet as in Example 1 was used, and thermoforming with heat treatment was performed.
1) Molding material: The same material as in Example 1 was used.
2) Molding device Molding machine: the same as in Example 1 was used.
Compressed air box; the structure shown in FIG. The dimensions were the same as in Example 1.
Mold: The same mold as in Example 1 was used.
3) Molding method and molding conditions
Preheating of resin sheet; 95 ° C
The same operation as in Example 1 was performed.
Preheating temperature of mold surface; 165 ° C
Air supplied from the pressure box; 275 ° C (original pressure 0.4 MPa)
Shaping process; 0.5 seconds, pneumatic pressure 0.4 MPa,
The compressed air box was lowered and joined to the mold, and at the same time, heated air was supplied from the air supply port 31. In addition, the vacuum suction from the mold was activated when the pressure box started to descend.
Heat treatment step: 2.3 seconds The operation valve 29 was opened and exhausted with a delay of 0.5 seconds from the compressed air shaping, thereby continuing to supply heated air to the compressed air space.
The mold surface (interface) temperature reached 185 ° C.
Cooling step: 0.8 seconds The operation valves 29 and 41 were switched, and the introduced normal temperature compressed air was continuously sent out from the exhaust port 21, and the sent air was collected in the air supply port 31 so that the exhaust continued. The vacuum operation from the mold side was also continued.
The mold surface (interface) temperature at the time of mold release dropped to about 160 ° C.
4) Results A clean molded product can be obtained in any part of the mold contained in the storage box, and a uniform heat treatment can be performed without changing any part of one molded product. I was able to.

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.
(5) 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 is converted into a material with reduced thickness, It is possible to contribute to the social needs for resource conservation.

30 Pneumatic box 21 Exhaust port (exhaust body)
22 Heating heater
23 Exhaust passage
24 Air collection space 25 Air intake opening 27 Heat insulating material 28 Air collection pipe 29 Operation valve 31 Air supply port (air supply body)
32 Heating heater 33 Compressed gas introduction path 34 Distribution space 35 Air supply opening 36 Air supply / exhaust surface
37 Box outer wall 38 Air pipe
39 Air pressure space
41 Operation valve 50 Cooling means 60 Mold (or mold group structure)
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
100 Thermoplastic resin sheet (resin sheet)
110 Shaped body A of thermoplastic resin sheet Compressed gas (gas for cooling)
A 'Exhaust HA High-temperature compressed gas (heating gas)
HA 'Exhaust of hot gas

Claims (9)

In a thermoforming apparatus that performs pressure forming of a resin sheet, as a compressed air box, at least cooling compressed gas is sent from the air supply opening to the upper part of the mold, and the sent gas is exhausted to the outside through the air intake opening at the upper part of the mold. Or at least 1) gas delivery from the air supply openings is performed by distributing from a distribution space provided behind the plurality of air supply openings, or 2) the exhaust air is collected from the plurality of air collections. An apparatus for molding a thermoplastic resin sheet, which is performed by collecting air in an air collecting space provided behind an opening, and using an integrated structure of the mechanism. The conduit leading to the air supply opening or the intake opening is provided to penetrate the air collection space or the distribution space, or to penetrate between the spaces, respectively. Molding equipment. 3. The molding apparatus according to claim 1, wherein either the air supply opening or the air intake opening is provided at a position closer to the molding die surface. 4. In order to change the gas sent in the middle of the molding process to one having a different temperature, and send out the gas, the mechanism for sending the gas from the air feed opening works as a mechanism for exhausting the gas from the middle, The molding apparatus according to any one of claims 1 to 3, wherein the mechanism for sucking and exhausting air from the intake opening is configured to function as a mechanism for sending a gas at a different temperature from the middle. 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 / m ² s ^1/2 K) of 0.01 to 25 is used. The molding apparatus according to any one of the above. The molding die comprises a surface layer made of a material having a thermal permeability (b value) of 20 or less and a back body made of a material having a thermal permeability (b value) larger than that of the surface layer. To 5. The molding apparatus according to any one of 5 to 5. As means for heating the shaped body held in the mold, at least one of 1) means for sending heated gas from the compressed air box, or 2) means for heating and using the mold is used. The molding apparatus according to any one of claims 1 to 6, wherein A resin sheet molding method using the molding apparatus according to claim 1, wherein the resin sheet is preheated, shaped, heat treated at a temperature higher than the sheet preheat temperature, and cooled. A method for forming a thermoplastic resin sheet comprising the steps. The method for heat-treating the shaped body at a high temperature uses at least one of 1) a method of sending heated gas from the compressed air box, or 2) a method of heating and using the holding mold. Molding method.

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