JP2012176567A - Apparatus and method for shaping resin sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an apparatus for shaping a resin sheet, capable of quickly heating a body to be shaped and capable of quickly cooling it as needed, in a process from shaping using thermoforming to die releasing, particularly capable of quickly, efficiently and continuously carrying out hot shaping in which heat processing at a temperature higher than a preheat temperature of the resin sheet before the shaping is carried out and the shaping die is released, and capable of obtaining a good-state shaped-product.SOLUTION: A compressed gas box 4 includes: a distributing send-out section 40 for performing distributing send-out of high-temperature compressed gas; a cooling section equipped with jetting nozzles 41 for jetting cooling gas toward a shaping die-placing box 3. The distributing send-out section 40 sends out the compressed gas to a thermoplastic resin sheet through an interspace formed between a shell of the compressed gas box 4 and the jetting nozzles 41. The apparatus for shaping the resin sheet further includes a heating section 50 for heating the compressed gas to be supplied to the distributing send-out section 40.

Description

  The present invention relates to a resin sheet molding apparatus and molding method. For example, 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 a high speed. In the process of thermoforming, heat treatment at a temperature higher than the preheating temperature of the sheet is performed, and in particular, for the production of thermoformed products with high properties such as heat resistance, transparency, and mechanical strength at high speed, stretching of the crystalline resin is especially important. It relates to performing this thermoforming using a 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 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.
(6) The method disclosed in Japanese Patent No. 4057487 relates to thermoforming of a crystalline resin. A sheet preheated by contacting a porous heating plate is formed into high-pressure air passing through the porous plate and a heated molding die. However, the temperature of the heating plate is adjusted to an appropriate sheet preheating temperature and is significantly lower than the heat treatment temperature. Also, such a hot plate is not intended for air heating, and therefore the temperature of the air passing through the hot plate is low and cannot contribute to a heat treatment above the preheated sheet temperature. The heat treatment temperature depends exclusively on the high temperature of the mold, but for mold release, cooling must be more drastically and efficient production is not possible.
In addition, the disclosure of (7) Japanese Patent No. 4044876 relates to thermoforming of a resin material in which sag (sag 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.

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. 4057487 Japanese Patent No. 4044876

  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 resin sheet molding apparatus and a molding method capable of continuously and efficiently performing mold release at high speed and obtaining a molded product in a good state.

(1) A resin that is configured so that a thermoplastic resin sheet can be sandwiched between a compressed air box and a mold storage box having a mold, and a thermoplastic gas sheet is molded by introducing compressed gas into the compressed air box A sheet forming apparatus,
The compressed air box is provided with a dispersion delivery unit that distributes and delivers high-temperature compressed gas, and a cooling unit that has an injection nozzle that injects a cooling gas toward the mold storage box.
The dispersion delivery unit is configured to send compressed gas to the thermoplastic resin sheet through a gap formed between the outer shell of the compressed air box and the injection nozzle,
Furthermore, the present invention provides a resin sheet molding apparatus including a heating unit that heats the compressed gas supplied to the dispersion delivery unit.
The dispersion delivery unit is a mechanism having a function capable of uniformly delivering the compressed gas toward the entire molding die of the molding die storage box. There is.
A) A method in which the gas flow is spatially divided and sent out, B) A method in which the gas flow is sent out while statically stirring and dispersing, C) A method in which the gas flow is sent out while dynamically stirring and dispersing, and D) There is a method of sending a gas flow while colliding and dispersing it. Any of these methods can be suitably used alone or in combination.
In addition, it is preferable that this dispersion | distribution delivery part is added with the heating mechanism, and the temperature is 255 degreeC or more, Furthermore, it is the structure which can be hold | maintained to the arbitrary temperature of 300 degrees C or more and below the temperature possible as an apparatus. It is preferred that
The heating unit is arranged at any appropriate place not limited to the inside of the compressed air box, and the introduced compressed gas having a gauge pressure of 0.02 MPa or more and 2.0 MPa or less is 255 ° C. or more, and preferably Has a function of heating to an arbitrary temperature of 300 ° C. or higher and lower than the temperature realizable as a device. And what has the mechanism which can discharge the high temperature compressed gas of predetermined temperature substantially instantaneously in the arbitrary intermittent for 30 seconds or less is preferable.
The spray nozzle preferably has a mechanism for spraying with a diffusion angle, and preferably has a diffusion angle of 20 ° or more.
The outer shell of the compressed air box is a housing portion that houses the dispersion delivery unit and the injection nozzle.
In addition, it is preferable that the shaping | molding die storage box which has the said shaping | molding die is comprised so that vacuum suction is possible.

(2) The compressed air box according to (1), wherein the compressed air box has a discharge hole that communicates with the outside a closed space formed between the mold storage box and the compressed air box in a sandwiched state of the thermoplastic resin sheet. A resin sheet molding apparatus is provided.
The external communication hole can be opened and closed at any necessary time in the molding cycle.

(3) Molding of the resin sheet according to (1) or (2), wherein the heating unit includes a heat accumulator having a large number of gaps serving as compressed air flow paths and a heater for heating the heat accumulator. Providing equipment.
In addition, this heating part is provided with the mechanism which sends high temperature compressed air to the said dispersion | distribution delivery part intermittently according to a molding cycle in the upstream or downstream.
In addition, the heater of this heating part has a capacity | capacitance which can always heat-maintain this heat storage body to 255-1300 degreeC, the suitable temperature of 300-650 degreeC desirably.
In addition, the gas contact area of the heat storage body of this heating part has a contact surface area of 3 times or more, preferably 10 times or more of the effective projection area of the compressed air box.
In addition, this heating part may be attached to either the inside or outside of the compressed air box, or may be arranged at a location away from the heating box and connected to the pipe.

(4) The said heating part provides the molding apparatus of the resin sheet in any one of said (1) to (3) integrated with the said dispersion | distribution delivery part.
In this case, the term “integral” means that both of them are fixed to the compressed air box, and there may be a space between the heating part and the dispersed gas delivery part, and the whole surface is in close contact with each other. Also good. The latter is more preferable.
In addition, it is also possible to select the heat storage body of the heating unit and the distributed delivery case to be the same object, which is also preferable.

(5) The resin sheet molding apparatus according to any one of (1) to (4), wherein an infrared emissivity of a surface of the compressed air box facing the mold storage box is 0.8 or more. .
The infrared emissivity is preferably 0.9 or more, and more preferably 0.95 or more.
In addition, when a reflective object is used as this gas dispersion | distribution delivery part, a reflective object is also contained in the object prescribed | regulated here. However, when the reflector is a mirror surface, the rear surface to be projected includes such an infrared emissivity.

(6) A molding apparatus for a resin sheet according to any one of (1) to (5), further including a liquid spraying unit that sprays a volatile liquid toward the thermoplastic resin sheet after shaping.
In addition, this spraying part may be in the inside of a compressed air box, and may be in the exterior. In addition, the spray unit may be a mechanism that also serves as the cooling gas spray nozzle, and may perform the spray and the spray alternately, or spray while mixing the liquid into the gas before spraying. You may make it do. This mechanism is also preferably used.

(7) From the above (1) to (6), the mold has a heat permeability (kJ / m ² s ^1/2 K) of a material constituting the molding surface of the thermoplastic resin sheet of 0.01 to 15. 3) a resin sheet molding apparatus according to any one of the above.
Note that the heat permeability of the material constituting the molding surface of this mold is preferably 10 or less, and more preferably 5 or less.
The mold may be made of a single material, or the back layer may be formed of two or more layers made of different materials.
The heat penetration of the material of the back layer is more preferably a two-layer or multi-layer structure made of a material higher than that of the surface layer. In that case, the heat penetration rate is preferably 2 times or more, preferably 10 times or more. It is particularly preferred. The back layer is preferably temperature-controlled. The thermal permeability of the back layer is preferably 3 or more, more preferably 6 or more, and even more preferably 10 or more. Further, the thickness of the molding 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 addition, it is preferable that the shaping | molding die is provided with the fine hole so that the evacuation at the time of vacuum shaping or shaping is possible.

(8) The resin according to any one of (1) to (7), wherein the compressed air box includes an infrared thermometer that continuously measures a surface temperature change of the thermoplastic resin sheet in a molding cycle in a non-contact manner. A sheet forming apparatus is provided.
Specifically, 1) this can be carried out by placing an infrared temperature measurement probe housed in a temperature-controllable shell structure and protected against heat inside the compressed air box.
Alternatively, 2) this can be done by deriving the infrared radiation from the back of the shaped body out of the compressed air box and placing an infrared temperature measurement probe there.

 (9) A resin sheet molding method using the resin sheet molding apparatus according to any one of (1) to (8) above, wherein a shaping step of shaping a thermoplastic resin sheet, and the shaping There is provided a resin sheet molding method including a heat treatment step of heat treatment at a higher temperature than the step.

  According to the present invention, in the process from thermoforming to mold release, the shaped body is heated at a high speed and, if necessary, is cooled at a high speed, and heat treatment is performed at a temperature higher than the preheating sheet temperature before shaping. It is possible to provide a molding apparatus and a molding method for a resin sheet that can be efficiently and continuously subjected to thermoforming to release molds and that can obtain a molded product in a good state.

It is sectional drawing which shows the principal part of the shaping | molding apparatus of this invention. It is the reverse view which looked at the compressed air box which is a part of apparatus shown in FIG. 1a from the downward direction. It is a top view which shows the example of a dispersion | distribution transmission part. It is a schematic cross section which shows the example of a dispersion | distribution delivery part. It is sectional drawing which shows a part of shaping | molding apparatus of this invention. It is sectional drawing which shows a part of shaping | molding apparatus of this invention. It is sectional drawing which shows a part of shaping | molding apparatus of this invention. It is sectional drawing which shows a part of shaping | molding apparatus of this invention. It is sectional drawing which shows a part of shaping | molding apparatus of this invention. It is a figure which shows the model temperature pattern of the thermoforming process using the shaping | molding apparatus of this invention. It is a figure which shows the model temperature pattern of the thermoforming process using the shaping | molding apparatus of this invention.

<Configuration of molding apparatus and its function>
The molding apparatus of the present invention constitutes a pressure forming machine or a vacuum / pressure forming machine that is a thermoforming machine, or a vacuum forming machine. Since the pressure forming machine or the vacuum pressure forming machine has a press mechanism, the thermoforming machine can be configured by mounting the portion of the present invention. A vacuum forming machine or the like that originally does not have a press mechanism can be configured by adding a press mechanism. Further, these thermoforming machines usually have a sheet preheating mechanism, and those having this can be suitably used. In addition, there are an indirect heating method such as an infrared oven and a hot air oven and a direct heating method in contact with a heated metal body, both of which can be used, but the former is more preferable. However, in the present invention, the material sheet need not have a preheating mechanism that is preheated by such a method, and can be preheated in the configuration of the present invention. In the present invention, a molding die storage box and a compressed air box opposite thereto are disposed between the top plate and the bottom plate of the press machine. In the example described later, a mold storage box is disposed on the bottom plate, and a compressed air box is disposed on the lower side of the upper plate. Each of them rises and descends to create a closed space with the molding material sheet interposed therebetween, and compressed air is started. It is a mechanism. In this case, only the top plate or the bottom plate may be movable. Moreover, these box mountings may be turned upside down, and a mold storage box may be disposed on the top plate side, and a compressed air box may be disposed on the bottom plate side. In addition, as a peculiar aspect, a press machine may be rolled over, and the above-mentioned heavy boxes can be opened and closed easily and used as a preferable method.
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 compressed air box is provided with a dispersion delivery section for delivering high-temperature compressed gas in a distributed manner so that the compressed gas can be delivered substantially uniformly and relatively gently toward the entire surface of the resin sheet and the mold. To. Further, a cooling unit having an injection nozzle is provided so that the cooling gas can be injected toward the mold storage box. Further, a heating unit for heating the compressed gas to be supplied to the dispersion delivery unit is provided at any appropriate place, and the high temperature compressed gas is sent to the dispersion unit.
And the high temperature compressed gas from the said dispersion | distribution delivery part is sent to a thermoplastic resin sheet to compressed gas through the clearance gap formed between the outer shell of the said compressed air box, and the said injection nozzle.
This heating unit is not limited to the above-described compressed air box, and may be disposed at an arbitrary place and connected to the pipe, but may be disposed in the compressed air box together with the dispersion unit.
The heating unit is a material having a heat and pressure resistance so that the introduced compressed gas having a gauge pressure of 0.02 MP or more can be heated to an arbitrary temperature of 255 ° C. or higher, preferably 300 ° C. or higher and below an allowable limit as an apparatus. And a heating means such as a heater. In addition, an open / close bubble or the like is provided so that a high-temperature compressed gas having a predetermined temperature can be ejected substantially instantaneously at an arbitrary interval of 30 seconds or less.
In addition, it is preferable that this dispersion | distribution delivery part is comprised so that the temperature can be hold | maintained at the arbitrary temperature which can be implement | achieved as an apparatus at 255 degreeC or more, and also 300 degreeC or more. For this reason, it is preferable to attach a heat insulating material to an appropriate place to prevent heat dissipation, and it is more preferable to attach a heating mechanism to the gas dispersion delivery unit.
The molding apparatus is preferably equipped with a vacuum suction function so that the resin sheet can be vacuum-sucked through a vacuum-type vacuum exhaust hole housed in the molding die storage box.

<About the above distributed sending unit>
The temperature of the hot compressed gas handled in the apparatus of the present invention is the melting point of many types of resins expected to be applied to the present invention or higher than that, and the high temperature compressed gas is not sufficiently dispersed. If the material comes into contact with the material before or during shaping, the molding becomes non-uniform, and in extreme cases, melt breakage progresses from a part and the molding becomes impossible. In addition, the heat treatment temperature rise after shaping is non-uniform, which is inconvenient. In order to solve such inconvenience, the dispersion delivery section is provided downstream of the high-temperature compressed gas introduction port, and the compressed gas is distributed substantially uniformly and gently toward the entire mold surface of the mold storage box. It can be so.
Any mechanism can be adopted as long as it has such a function as a distributed delivery unit. Specifically, although not limited to these, A) a method in which a gas flow is spatially divided and sent out, B) a method in which the gas flow is sent while being statically stirred and dispersed, and C) a gas flow is moved A method of sending while stirring and dispersing and D) a method of sending while dispersing and colliding the gas flow can be adopted, and each can be used alone or in combination.
If these are described in more detail,
Examples of belonging to A) include, for example, a) a structure in which high-temperature compressed gas is distributed and sent out from a plurality of openings (referred to as outlets);
b) A structure having one or a plurality of openings, the opening shape being a long slit shape, or a narrow detail in at least a part of the opening shape.
c) having one or a relatively small number of gas delivery centers, the centers delivering gas with a diffusion angle;
For example, as belonging to the above B), d) an obstacle that is permeable to the body is disposed downstream of the high-temperature compressed gas inlet. In addition, such an obstruction may be arrange | positioned so that a downstream may be closed, and may be arrange | positioned only in the place which faces the strong airflow just under a gas inlet, without closing.
e) One or a relatively small number of large delivery ports are provided in the dispersion delivery unit, and a mechanism for dispersing the gas in or around the opening hole is provided.
For example, f) a jet outlet is provided with a movable disturbing member such as a rotary blade downstream of the high-temperature compressed gas inlet.
g) A movable disturbing member such as a rotor blade is mounted at or just below the opening of the dispersion delivery section.
For example, h) having a structure in which gas jetted from one or a relatively small number of small openings provided in the compressed air box is reflected by a reflector and distributed and sent, as belonging to D) above,
i) A mechanism for colliding and dispersing gas flows ejected from a relatively small number of small openings In the case of a), the shape of the openings is arbitrary, but a plurality of openings must be provided. And more preferably 10 or more, and particularly preferably 30 or more and innumerable. In the case where the opening shape is simple and the number is less than 10 and is small, it is desirable that the hole diameter (long dimension of the opening passing) is relatively large such as 10 mm or more. It is desirable that the gas flow is homogenized to some extent by means based on the method D. It should be noted that the opening is a hole or hole outlet, but it may or may not match the shape and number of upstream inlets. In addition, the entrance and exit portions may pass directly through the inside of the diffuser, and may be via branches or air. Specific examples of usable objects include, for example, perforated metal plates, thin sintered metal plates, and glass. Alternatively, carbon or metal fiber woven fabric, wire mesh, and the like can be given. As a representative of this method, an example of a perforated plate perforated is shown in FIG. In addition,
Instead of closing the downstream of the hot gas with such an opening plate, a pipe with an opening may be inserted into the compressed air box, and the hot gas may be fed into the pipe, and the form is arbitrary.
In the case of the above b), if the number of slit portions is increased or lengthened in one opening, it is easy to disperse and send out regardless of the number. For example, if a slit-like opening is provided so as to go around the entire surface of the dispersion delivery section, even if there is only one opening, the substantial effect is the same as that obtained by sufficiently dividing the gas flow. As an example of this method, FIG. 2B shows an example in which a flat plate is formed from a continuous slit, that is, a single opening.
In the case of c), specifically, a gas injection nozzle capable of diffusion injection is used at the center of gas delivery, or a dispersion mechanism is formed inside a relatively large opening. For example, as shown in FIG. 5, the former injection nozzle can be manufactured by arranging a large number of small holes by changing the inclination angle little by little. Specific examples of the latter dispersion mechanism include “a hole that increases toward the outlet encloses a static mixer that increases along the hole”, “discharges a gas in a cyclone (around the hole wall surface)”, “ Give a mechanism such as “provide a spiral groove in a hole or enclose a spiral rib”, “provide a large number of inclined sub-injection ports at the back of the hole”, “provide multiple divergent slits concentrically in individual holes”, etc. Can do.
In the case of d), specific examples of such obstacles include the following substances and objects.
It is made of highly heat-resistant materials such as metal, glass, ceramics, graphite, etc., and these rods, needles, granules, amorphous, filaments, filaments, fibers, etc. Each aggregate, a porous body, a perforated body, etc. can be mentioned. In the case of the former assembly, individual objects may be joined or simply entangled, and may be woven or knitted if they are filamentous, linear or fibrous. . If the objects dissipate apart, they can be used as an aggregate by using a gas-permeable material such as a wire mesh.
In the case of e), if a specific example is given, for example, a method of placing a gas permeable obstacle inside or in the vicinity of the outlet, a specific object as mentioned in d) above is used. Use it. Alternatively, mention may be made of the methods exemplified in the above c) (design without a dispersion angle) such as “providing a spiral groove or rib in the opening, or on the inner wall of the opening”, “attaching a static mixer in the opening”, etc. Can do.
In the case of the above f) and g), it may be independently operated by a gas flow, or power may be applied from the outside.
Specific examples include a rotary blade and a rotary pendulum.
In the case of h), the number of reflectors is not limited, but the number and shape of the ejection ports can be arbitrarily designed, and the number or form of the reflectors can be arbitrarily designed.
The reflector may be a flat plate, may be concave or convex, may have a bent shape, or may have complex irregularities, and does not limit the shape, so that uniform gas delivery is possible. Can be designed arbitrarily. A typical example of this method is shown in the schematic cross-sectional view (h) of FIG. 3 and the cross-sectional view of FIG. (H) is a method in which the jet gas from the opening of the jet reflection plate 91 serving both as jet and reflection is reflected by the target reflector 92 and the reflected gas is further reflected by the jet reflector 91 and dispersed. FIG. 4 will be described later.
In the case of i), a typical example of this method is shown in the schematic cross-sectional view (i) of FIG. In this example, a high-temperature compressed gas A ′ sent via a conduit 95 is ejected from 96 slits and collided with a plurality of slit pipes 96 arranged opposite to each other in the compressed air box. Is.

<About the heating unit>
The heating unit introduces compressed gas generated by a known gas compressor or the like, heats it to a desired temperature, which will be described later, and substantially instantaneously at an arbitrary interval of 30 seconds or less. It is necessary to provide a mechanism capable of discharging a high-temperature compressed gas having a desired constant temperature. Specific examples thereof will be described later. Here, “constant temperature” means that the temperature rise profile is not shown over time after the start of discharge.
The pressure of the hot compressed gas generated by heating needs to be a gauge pressure of 0.02 MPa or more. If the pressure is lower than this, sufficient shaping cannot be performed, preferably 0.1 MPa or more, and further 0.2 MPa. The above is desirable. Although the upper limit is not specified, there is a limit due to the strength of the device. In addition, when this pressure is less than 0.02 MPa, it is not possible to perform sufficient pressure forming, and it is not possible to send heated gas quickly, so it takes a long time to raise the temperature of the heat treatment. Interferes with efficient production.
The temperature of the high-temperature compressed gas is mainly related to the rate of temperature rise to the heat treatment temperature, needs to be 255 to 1300 ° C, and preferably 300 to 650 ° C. When the temperature is 255 ° C. or lower, the shaped body that is in close contact with the mold cannot be heated at a high speed and heat-treated, and is preferably 300 ° C. or higher. When the upper limit of 1300 ° C. is exceeded, the device manufacturing cost is large and impractical, and it is desirable that the temperature be 650 ° C. or lower.
The above high-temperature compressed gas requires 1) preheating to the forming temperature if necessary, 2) performing pressure forming if necessary, 3) higher heat treatment temperature in the process following shaping. 4) If necessary, it can be continuously performed without interruption, such as preventing the deformation of the shaped article by continuously pressing the material during the heat treatment to the mold. In the present invention, 3) is an essential function that cannot be replaced by other means.

<About the above cooling unit>
The above-mentioned compressed air box is equipped with a mechanism that can inject cooling gas toward the mold surface, optionally opening part of the closed space of the compressed air box and finally opening the cooling gas. Try to spray. This gas injection has the function of 1) cooling the shaped body to a moldable temperature and 2) pressing and fixing the shaped body to the mold to prevent deformation. The latter is particularly effective when a part of the closed space is opened.
The effect of 2) is also effective in evacuation from behind the mold, and the use of this evacuation is more preferable for fixing the shaped body. The injection mechanism may also be movable within the box to the desired horizontal or vertical position during its operation, which is desirable. This is because a part of the molded product often needs to be exaggerated for cooling according to its shape and the like. The number of injection nozzles is not limited, but it is preferable that each nozzle has a structure capable of diffusing injection. Also, when a large mold or a plurality of molds are used, a plurality of injection nozzles may be used. preferable.
The low-temperature compressed gas is a compressed gas having a normal temperature at which heating is not performed or a temperature lower than the high-temperature compressed gas used.
In addition, it is desirable that the injection nozzle has a mechanism that performs diffusion injection with a diffusion angle. The diffusion angle is desirably 20 ° or more, and desirably 180 ° or less.
In addition, the said injection | spray nozzle is made so that it may serve as the plug which pushes down a resin sheet, and plug assist shaping can also be performed by moving this up and down, and provides one useful aspect.

In relation to the above-described apparatus of the present invention, (2) of “Means for Solving Problems” will be described in detail. In the molding apparatus described in detail above, the compressed air box is provided with a discharge hole that arbitrarily communicates the closed space in the compressed air box formed with the thermoplastic resin sheet sandwiched with the outside. An opening / closing mechanism is provided in the middle of the pipe communicating with the external communication hole so that the opening / closing mechanism can be opened and closed at any necessary time in the molding cycle.
By using such an apparatus, it is possible to exhaust the air staying inside the compressed air box somewhere in the compressed air shaping process and the subsequent heat treatment process, and to send new hot gas from behind, This is very desirable because heat treatment can be performed by raising the temperature of the shaped body quickly by heat transfer with high birth efficiency. Further, it is desirable that the cooling gas can be continuously fed in, and cooling can be performed while preventing the deformation by pressing the shaped body against the mold in a certain pressure state. Further, if the pressure box is pulled away from such a state, a desirable operation can be performed without causing rapid pressure fluctuation and without causing the shaped body to shift. In addition, in the process from shaping to mold release, the combined use of evacuation from the back of the mold is very desirable. In addition, the mechanism does not use a high-temperature compressed gas in the shaping step, but also facilitates vacuum-only shaping or pressure shaping with room temperature gas, and provides a preferred molding method.

In relation to the above-described apparatus of the present invention, (3) of “Means for Solving Problems” will be described in detail. That is, in any one of the molding apparatuses described in detail above and above, the heating unit includes a heat accumulator having a large number of gaps serving as compressed gas flow paths introduced from the outside, and a heater for heating the heat accumulator. Consists of. An opening / closing mechanism is provided somewhere upstream or downstream of the heating unit so that the high-temperature compressed air can be intermittently sent to the dispersion delivery unit in accordance with the molding cycle.
Moreover, this heater uses the thing of the capacity | capacitance which can always heat-maintain this thermal storage body to 255-1300 degreeC, the suitable temperature of 300-650 degreeC desirably. In addition, since the gas temperature produced | generated is low at the temperature which is less than 255 degreeC at this temperature, rapid temperature rising heat processing cannot be performed, and it is desirable that it is 300 degreeC or more. If the upper limit of 1300 ° C. is exceeded, the device manufacturing cost is high and impractical.
The gas contact surface area of such a heat storage body needs to be 3 times or more, preferably 10 times the effective projected area of the compressed air box. In addition, when this magnification is less than 3 times, it will hinder high-speed continuous repetitive molding.
This heating device may be installed in or adjacent to the compressed air box, or may be arranged separately and connected by piping. The compressed gas may be generated by a known method such as a compressor.
For heating the heat accumulator, any of known methods such as electric heater heating, dielectric heating, fuel combustion, and the like can be used.
The molding apparatus using this heating apparatus can be suitably used for high-speed and stable continuous molding. It also provides a way to minimize energy consumption.
The high-temperature gas as described above can be easily obtained by directly contacting air or the like with a heating element or flame such as an electric heater, or by burning a combustible material. Is commercially available. However, there is a problem in using any of these. For example, there are many types such as an electric heat blower. However, when these apparatuses attempt to generate a heated gas intermittently in accordance with a pressure forming cycle, the following problems occur. 1) If compressed air is introduced intermittently to a heater that is always energized and heated, the heater is likely to be overheated and damaged in the intermittent period when there is no air flow, and 2) it is energized intermittently. If this is done, it takes time to heat up each time electricity is applied, and efficient heat treatment molding is not possible. 3) Always conduct current to generate high-temperature gas, use it whenever necessary, and let it escape to the outside when not needed. This will solve these problems, but it will cause a significant loss of energy. On the other hand, a method by direct contact with a flame and a method of generating and using a high-temperature combustion gas are also conceivable, but the apparatus becomes complicated and undesirably expensive due to a large cost for ensuring safety.
Note that a high temperature cannot be obtained with a general heat exchanger, and it is difficult to realize a stable high temperature that is instantaneously heated and repeatedly with a small air contact area of the medium. In the case of the present invention, a large amount of high-temperature gas is required instantaneously for each molding cycle, and it is necessary to provide a device having a sufficient air contact area of the heat medium required for the molding die area.

In relation to the above-described apparatus of the present invention, (4) of “Means for Solving the Problems” will be described in detail. That is, in any one of the molding apparatuses described in detail above and above, the heating unit is integrated with the dispersion delivery unit. That is, in this case, the term “integrated” means that both are fixedly present in the compressed air box, and there may be a space between the heating part and the dispersed gas delivery part, or the two may be in close contact with each other. . However, the latter is more preferred. By doing so, it is possible to produce a molded product with no waste as a whole apparatus, good operability, efficiency, and low energy loss.
In addition, it is possible to select the same material for the heat storage body of the heating unit and the dispersion delivery case, which is a case where the heat storage body can be fixed in a porous and constant shape as a whole, for example, a sintered body such as metal, Alternatively, it can be realized by metal particles fixed to a wire mesh basket.

In relation to the above-described apparatus of the present invention, (5) of “Means for Solving Problems” will be described in detail. That is, in any of the molding apparatuses described in detail above and above, the infrared emissivity of the surface of the compressed air box facing the storage box is set to 0.8 or more. Desirably, the infrared emissivity is 0.9 or more, and more desirably 0.95 or more. Specifically, it can be easily carried out by application of a commercially available black body paint for infrared radiation.
In many embodiments, the “opposing surface” is formed by the distributed delivery unit. However, depending on the embodiment, the “opposing surface” may be simply the back bottom surface of the compressed air box. Moreover, when a reflective object etc. are used for a dispersion | distribution transmission part, these are also contained in the opposing surface prescribed | regulated here. However, when the reflector is a mirror surface, it is also effective to make the projected rear surface have such an infrared emissivity. Specifically, it can be easily carried out by application of a commercially available black body paint for infrared radiation, etc. Note that the above-described facing surface is at a high temperature of 255 ° C. or higher, preferably 300 ° C. or higher in order to be effective in the present invention. It is necessary to be. In order to maintain the high temperature, a mechanism for heating the surface may be attached to the facing surface, or a heat insulating material may be kept warm where necessary.
The infrared rays radiated here function to 1) preheat or preheat the molding material to the shaping temperature, and 2) promote the temperature rise to the heat treatment temperature in the process following the shaping. When this surface temperature is less than 255 ° C. and the infrared emissivity is less than 0.8, the remarkable effects of 1) and 2) are not exhibited.
When this apparatus is used, a thermoforming device such as an oven or the like that does not have a preheating mechanism may be used, and even a material that is not sufficiently or not preheated at the time of the compressed air box of the present invention will have a slight preheating time or preheating. It is possible to adopt a method of shaping at almost the same time. When molding a crystalline resin or a stretched material of a crystalline resin, if preheating is sufficiently preheated in an oven or the like, crystallization and heat setting may progress during that time, which may hinder shaping. Since there are many, this apparatus can be utilized suitably.

In relation to the above-described apparatus of the present invention, (6) of “Means for Solving Problems” will be described in detail. That is, in any of the molding apparatuses described above and in detail above, a liquid spraying section for spraying a volatile liquid toward the thermoplastic resin sheet after shaping is provided.
In addition, this spraying part may be in the inside of a compressed air box, and may be in the exterior. Moreover, this spraying part may be a mechanism that also serves as the cooling gas injection nozzle, and this method is also preferably used. In this case, liquid spraying and gas injection may be performed alternately, or a volatile liquid may be mixed into the gas and sent to the injection nozzle.
By spraying a volatile liquid simultaneously with or before and after the emission of a reject gas by such a device, the shaped body is rapidly cooled by the liquid itself and its latent heat of vaporization, and can be released in a short time. Thus, the molding cycle is significantly shortened.
The volatile liquid to be sprayed works to effectively lower the temperature of the shaped body and the cooling gas by the latent heat of vaporization. Examples of such a liquid include water, alcohol and the like, and the former can be preferably used.

(7) of “Means for Solving the Problems” will be described in detail in relation to the above-described detailed apparatus of the present invention. That is, in any one of the molding apparatuses described in detail above and above, the above-described molding die to be used is the thermal permeability b value (kJ / value) of the material constituting the molding surface of the thermoplastic resin sheet. m ² s ^1/2 K) is 0.01-15. This makes it possible to perform molding with heat treatment quickly and suitably.
The heat permeability b value of this molding surface layer material is preferably 10 or less, and more preferably 5 or less.
This mold may be composed of a single material as long as the above surface layer is the above material, and the back layer may be formed of two or more layers made of different materials. The heat penetration of the material of the back layer is preferably made of a material higher than that of the surface layer, which is preferably 2 times or more, particularly preferably 10 times or more. The back layer is preferably temperature controlled.
However, the mold is preferably composed of a surface layer and a back layer made of a material having higher heat penetration, and the back layer is preferably temperature-controlled.
The thermal permeability of the back layer is preferably 3 or more, more preferably 6 or more, and even more preferably 10 or more. Further, the thickness of the molding 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.
The heat permeability b value will be described in detail later, but when a surface material having a large value is used, heat is easily dispersed from the shaped body to the back, so the heat capacity is relatively small. Heated air or cooling air cannot easily heat and cool the shaped body, and when this value is a material exceeding 10, molding that efficiently performs heat treatment cannot be performed. 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.

In relation to the above-described apparatus of the present invention, (8) of “Means for Solving Problems” will be described in detail. That is, in any of the molding apparatuses described in detail above and above, the compressed air box includes an infrared thermometer that continuously measures the surface temperature change of the thermoplastic resin sheet in the molding cycle in a non-contact manner.
Specifically, this is performed by 1) placing an infrared temperature measurement probe housed in a temperature-controllable shell structure and protected against heat, inside the compressed air box.
Alternatively, 2) this is accomplished by directing the infrared radiation from the back of the shaped body out of the compressed air box and placing an infrared temperature measurement probe there.
There are no commercially available infrared thermometers that can be used in the pressure box of the apparatus of the present invention and can withstand use, and those that can withstand use are rare. For this purpose, the above-described device is required.
By such temperature measurement, the preheating, shaping, temperature rising heat treatment temperature and temperature change of the cooling process of the thermoplastic resin sheet can be measured continuously and seamlessly for control and process management. Highly preferred.
In the conventional thermoforming method, it is sufficient that the preheating temperature is measured in an oven and the shaped body temperature is replaced with a mold temperature having a large heat capacity or the cooling process of the shaped body is measured from an open space. In addition, each measurement was not continuous. Further, in the conventional normal pressure forming, it is not necessary or performed to measure the sheet temperature or the shaped body temperature in a closed pressure box.
In the apparatus of the present invention, instead of the above temperature measuring method, an extremely delicate measuring 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 measured. can do. However, this method has the disadvantages that the temperature of the resin sheet before shaping cannot be achieved and the durability of the measurement probe is small.
The above methods 1) and 2) will be described in more detail. First, as a method of 1), an infrared measurement probe is accommodated in a water cooling holder, and a cooling body such as water is circulated from outside the compressed air box to be cooled, so that it can be used at a high temperature and can be used. Further, instead of the water cooling holder, a holder equipped with a heat pipe may be used to cool the outside. The infrared measurement probe preferably uses an infrared voltage conversion element. The method 2) is a method in which radiant infrared light is guided to the outside of the compressed air box via a reflecting object or a refracting object and measured. More specifically, a specular reflector, a prism, an optical glass fiber, or the like can be used. A method using an optical fiber is also conceivable, and can be used when an instrument is developed at a low cost.

Regarding the molding method using the apparatus of the present invention, (9) of “Means for Solving Problems” will be described in detail. That is, using any of the molding apparatuses described in detail above and above, molding a resin sheet comprising a shaping step for shaping a thermoplastic resin sheet and a heat treatment step for heat treatment at a higher temperature than the shaping step. Can be implemented. In the method of the present invention, this molding can be performed efficiently at high speed, and is particularly suitable for high-speed continuous molding using a long resin sheet.
Thermoforming is usually performed through a process of preheating, shaping, cooling, and releasing a resin sheet.
It is usually done using a relatively low temperature mold, and shaping and cooling are almost simultaneously performed and no other means for cooling is required.
On the other hand, in the present invention, the molding is characterized by performing a heat treatment at a temperature higher than that at the time of shaping the resin sheet between shaping and cooling, and is usually preheating, shaping, and high-temperature heat treatment of the resin sheet. , Cooling and mold release process.
In the present invention, the preheating of the resin sheet can be performed in a heating oven or the like at a place away from shaping as in a normal method. In such a preheating method, the sheet temperature is lowered during the movement of the resin sheet or the oven, and the target resin sheet of the present invention is often inconvenient. However, in the apparatus of the present invention, preheating in a heating oven or the like is intentionally made insufficient, and the preheating is substantially replenished with heated gas or radiant infrared rays at the shaping position, and immediately pressurized and shaped. And provides a preferred method. Moreover, without preheating in such a heating oven or the like, a preferred method can be provided in which preheating can be performed in the same manner at the forming position, and the compressed air can be immediately formed. Furthermore, in the present invention, by adjusting the pneumatic pressure speed, preheating and shaping can be performed simultaneously, and a preferable method is provided.
In the present invention, compressed air shaping may be performed by the above-described high-temperature compressed gas used for heat treatment temperature rise, but alternatively, vacuum shaping or compressed-air shaping by room temperature compressed gas is performed without using this, and then the above high-temperature compressed gas is used. You may perform the heat processing temperature rise by compressed gas.
In the present invention, the temperature rise to the heat treatment temperature is performed mainly by bringing the heated gas into contact with the back surface of the shaped body (the surface not in contact with the mold). At this time, infrared heating can also be applied to the back of the shaped body, and it is particularly effective and preferable if used together with high-temperature gas heating. Further, the cooling after the heat treatment is mainly performed by spraying a cooling gas on the back surface of the shaped body.
Certain types of crystalline resins, or stretched materials of crystalline resins, are very sensitive to heating. Usually, oven preheating causes crystallization or heat setting in a short time during preheating, which hinders shaping. Resulting in. In the apparatus and method of the present invention, it is significant that the material can be shaped while being instantaneously preheated or auxiliary preheated at a fixed position, and molding with high temperature heat treatment can be continuously repeated at high speed. Is commercially useful.
A more detailed description of the molding method using the apparatus of the present invention will be described later with reference to the drawings. A molding material suitable for the method of the present invention will also be described later.

One specific example of the present invention is shown in FIG. FIG. 1a shows a cross section of a device mounted on a top plate and a bottom plate of a press machine arranged downstream of the oven preheating process of a sheet of a continuous vacuum / pressure forming machine as a main part of the apparatus of the present invention, and an arrangement outside thereof. A part of the device is shown. Specifically, a pressure box outer shell 4 equipped with various components is incorporated under the top plate 1 of the press machine, and a mold containing the mold and equipment is stored on the bottom plate 2. Box 3 is assembled. FIG. 1b is a bottom view of the compressed air box of FIG. 1a looking up from below.
The heating unit 50 arranged outside further heats the compressed gas A introduced from the outside to a predetermined temperature here, and is intermittently sent to the compressed air box according to the molding cycle.
The pressure box outer shell (hereinafter also referred to simply as “pressure box”) 4 is equipped with a dispersion delivery unit 40 composed of a perforated aluminum perforated plate to disperse the high-temperature compressed gas A ′ sent from the outside. Thus, the resin sheet 100 is fed uniformly and relatively gently toward the resin sheet 100. A cooling injection nozzle 41 is further arranged inside the compressed air box 4, and a cooling gas C such as compressed air is introduced from the outside via a control valve 43, and the timing of heat treatment completion of the molding material is confirmed. It is designed to spray cool toward the back of the shape. In the figure, one injection nozzle is arranged corresponding to the position of each mold. In addition, each injection nozzle is provided with a large number of openings so as to cover each type of cooling-necessary portion and enable diffusion injection. The number of injection nozzles is not limited and may be provided as necessary.
As an option, an exhaust slit pipe 44 is disposed in the compressed air box, and the control valve 46 can be opened and exhausted to any degree at any time during or after shaping. The slits of the exhaust slit pipe 44 may be continuous or intermittent, and may not be tubular, and those having an arbitrary opening shape are appropriately dispersed. Also good. Thereby, the heating temperature of the shaped body can be rapidly raised by the high-temperature gas flow that is replenished by escaping the staying gas.
Further, as an option, the emissivity of the compressed air box is made close to 1.0 by applying a black body paint to the mold facing surface, that is, the surface of the perforated plate 40 of the gas dispersion portion.
As an option, the pressure air box is further provided with a spray nozzle 13 for spraying the volatile liquid fed from outside while controlling the back of the shaped body and the sky above it. The volatile liquid is sprayed after compressed air shaping and heat treatment, immediately before, simultaneously with, or before and after the emission of the cooling gas, thereby promoting cooling of the shaping material. Note that the number of spray nozzles is not limited to one and may be appropriately plural. The spray nozzle may not necessarily be provided in the compressed air box but may be provided outside. In this case, the compressed air box is raised and sprayed toward the exposed back surface of the shaped body or above.
A plurality of molds as shown in FIG. 8 (those without the heat medium passage 65) are accommodated in the mold storage box 3, and the mold is a heater 34 (here, a cartridge type containing an electric resistance wire). ) Is fixed by a mold heating temperature control plate provided with a temperature control, and the heating temperature is adjusted, and 31 vacuum suction is possible from the vacuum exhaust hole 63 via the passages 64 and 35. Although not shown in FIG. 8, the temperature sensor of the fine core exposes the tip of the molding surface of the mold, and the temperature of the molding surface and the interface temperature with the shaped material of the molding material can be measured. ing. In addition, the surface which contacts the shaping | molding die of a resin sheet is called a molding surface, and the opposite surface shall be called a back surface below.
The heating unit 50 in the figure heats compressed air having a gauge pressure of 0.03 MPa or more introduced from the outside, and sends high-temperature compressed gas A ′ having a temperature of 255 to 1300 ° C., preferably 300 to 650 ° C., to the compressed air box 4. It has become. Uniform delivery is performed from the perforated plate 55 for delivery toward the mold. Specifically, a heating unit as shown in FIG. 6 may be used.
With this molding apparatus, the preheated crystalline resin sheet can be heated to a temperature equal to or higher than the preheating temperature almost simultaneously with or immediately after the pressure forming, and can be cooled and released. This molding process can be carried out stably at high speed and continuously. This process can be preferably used for a stretched material, and particularly preferably for a stretched PET sheet. With a stretched PET sheet, a preferable molded product that is transparent and has high heat resistance and rigidity can be obtained.
In addition, in this apparatus, following the vacuum shaping, the temperature increasing heat treatment using the high-temperature compressed gas can also be performed. The latter method is suitable when the resin sheet is thin and too sensitive to heat.

  FIG. 4 shows a mode different from that shown in FIG. The dispersion delivery unit 40 includes a reflection plate 71, a high-temperature compressed gas injection slit 75, and an introduction pipe 74 of the same gas. The reflection plate 71 is controlled by a heater 72 to an arbitrary temperature between 255 and 1000 ° C. The reflective surface 73 is coated with a black body paint and radiated with infrared rays, and the surface is directed toward the mold. A high-temperature compressed gas generated by a generator as shown in FIG. 6 is introduced into the introduction pipe 74 at a controlled time, and is sent to the mold direction via 75 and 73. The temperature rise of the shaped body can be promoted by the infrared radiation of the reflecting surface 73. In addition, in this apparatus, the temperature raising heat treatment with the same gas can be performed following the pressurized air shaping with the high-temperature compressed gas. Subsequent to the shaping, a temperature raising heat treatment with the above-mentioned high-temperature compressed gas can also be performed. The latter method is suitable when the resin sheet is thin and too sensitive to heat.

   FIG. 5 shows still another aspect of the high-temperature gas dispersion and delivery unit different from those shown in FIGS. 1 and 5. This mode is an additional nozzle type dispersion delivery unit 40 comprising a high-temperature gas distribution board 81, a manifold 83 and a dispersion nozzle 85. The distribution plate 81 is controlled to an arbitrary temperature between 255 and 1000 ° C. by a heater 84. Further, a black body paint is applied to the surfaces of the distribution board 81 and the dispersion nozzle 85 facing the mold, and infrared rays are emitted. The high-temperature and high-pressure gas generated by the generator as shown in FIG. 6 is introduced into the introduction path 82 at a controlled time, and is sent out toward the resin sheet via 83 and 85. The compressed air box is not provided with a high-temperature gas exhaust mechanism, but the temperature rise on the back of the shaped body is promoted by infrared radiation.

  FIG. 6 shows an example of a heating unit 50 of compressed gas. Inside the housing 56, a cartridge type heater 53 containing an aluminum particle 54 and an electric resistance wire as a heat storage body is inserted, and the outside is a heat insulating material. 59 is kept warm. A high-temperature compressed gas A ′ of 255 to 650 ° C. generated by instantaneously heating the compressed air A having a gauge pressure of 0.03 MPa or more introduced from the outside can be sent out toward the compressed air box. Then, by opening / closing the added opening / closing valve 58, A is intermittently introduced in accordance with the molding cycle, and A 'is sent out.

Further, the cross-sectional view of FIG. 7 shows an example in which the heating unit and the dispersion delivery unit are in close contact with each other and attached to the compressed air box.
A part of the compressed air outer shell 4 and a large number of holes are perforated. A box-shaped space in which the bottom is formed by the dispersion and delivery unit 40 of a metal plate incorporates an aluminum particle heat storage body 54 and a heater 53. Compressed air with a gauge pressure of 0.03 MPa or more introduced from is heated to 255 to 600 ° C., and is uniformly and relatively gently delivered from the dispersed delivery part 40 of the perforated plate toward the resin sheet. ing. In addition, a sintered body such as a metal can be used instead of the aluminum particles, and in this case, the parts of the dispersion delivery unit can be omitted, and the heat storage body such as the sintered body can also have the function.

FIG. 8 shows a specific example of the mold. The molding die 60 has a two-layer structure of a molding surface layer 61 and a back layer 62 thereof, 63 is a vacuum exhaust hole, 64 is a vacuum exhaust passage, and 65 is a heat medium passage for temperature control. Note that the temperature control means such as the heat medium passage is not provided here, and an arbitrary means may be provided for the fixing plate for fixing the molding die.
The molding surface layer of this mold is formed of an arbitrary material having a thermal permeability (kJ / m ² s ^1/2 K) of 0.01 to 15 and an arbitrary thickness of 5 to 30 mm, The heat permeability of the material of the back layer is larger than that of the surface layer and is made of any material of 3 or more and with any thickness. By providing such a back layer and adjusting the temperature from the back layer, the temperature of the surface layer can be adjusted quickly, effectively, and uniformly, so that the most preferable configuration is obtained. The heat permeability and specific materials will be described later.

<Detailed explanation of additional devices, materials, etc.>
(1) The thermal permeability (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.

(2) As the high-temperature and high-pressure gas used in the present invention, air, nitrogen, carbon dioxide and the like can be used, and those heated using compressed air with particularly low cost are preferable. In addition, water containing moisture, that is, dried superheated steam, can be suitably used because it has a large specific heat and can effectively heat the object.
(3) As the cooling gas used in the present invention, air, nitrogen, carbon dioxide and the like can be used, and those heated using compressed air with particularly low cost are preferable.
Moreover, the thing containing water | moisture content, ie, the thing of high humidity, can be used suitably. Furthermore,
If a droplet of a volatile liquid such as water is added to the cooling gas immediately before or during the spraying, the gas temperature is effectively lowered.

<Other modified embodiments>
(1) As a special aspect of the apparatus of the present invention, the target molded article can be manufactured by omitting a sheet preheating mechanism such as an oven by specially devising the operation of the apparatus of the present invention. As a specific method, a non-preheated molding material sheet is sandwiched between a compressed air box and a mold storage box (hereinafter referred to as box closing), and preheated by infrared radiation from the back of the compressed air box. It is possible to perform molding with control setting so that compressed air shaping is started after a certain time. As another method, it is equipped to send out hot gas gradually before closing the box or at first after closing the box, and the compressed sheet is compressed while the sandwiched sheet is preheated or preheated to an appropriate temperature. There is a method to set it so that it is shaped. When pressure forming is performed almost simultaneously with the closing of the box as in normal pressure forming, the material is damaged and a molded product cannot be obtained.
(2) As another special aspect of the apparatus of the present invention, a method of transferring to a heat treatment step with the high-temperature and high-pressure gas after pressure forming with a normal-temperature gas is also possible. Specifically, this may be done by providing an opening for sending air at a normal temperature into the compressed air box, and the compressed air gas can also be temporarily released from the cooling gas-like nozzle provided as a necessary element of the present invention. You can also do this by equipping
(3) As another special aspect of the apparatus of the present invention, it may be equipped to use dry superheated steam as the high-temperature and high-pressure gas. Specifically, a small amount of water or water vapor may be injected into the high-temperature gas generator of the present invention together with high-pressure air or the like.
<Details of application field of the apparatus of the present invention and molding method using the same>

The apparatus of the present invention can efficiently perform a process of heat-treating at a high temperature substantially exceeding the preheating temperature of the resin sheet and then cooling and releasing it in the process of preheating and releasing the resin sheet. .
Specific applications requiring such heat treatment are as follows: (1) It can be particularly suitably used for heat-fixing molding of stretched polyester. Besides, thermoplastic polyester resin, PLA resin, polypropylene, polyamide, PEEK, etc. It is possible to utilize a stretched sheet of crystalline resin by heat-fixing molding. Of these, the stretched polyethylene terephthalate resin sheet can be particularly suitably used for thermoforming with heat setting, and is heated to a preheating temperature of 80 to 100 ° C. and quickly heated to 160 to 190 ° C. suitable for heat setting. And it can take the process of quick cooling and mold release.
Also, it is applied to materials that have not been particularly stretched, such as (1) molding of normal crystalline PET (CPET), or (3) polypropylene SPPF molding (solid phase high pressure molding). It is possible to propose a novel method for solving (relaxing residual stress strain and improving heat-resistant dimensional stability).

Thermoforming performed using the apparatus of the present invention has wide versatility, and various molding patterns that involve heat treatment at or above the molding material sheet preheating temperature can be employed. As one of the typical patterns, FIG. 9 shows a pattern (pattern A) schematically representing the surface temperature trajectory of the mold associated with the continuous molding. Here, a constant steady temperature (S-line), indicated by the back layer of the mold or the surface layer deep near the back layer, is arbitrarily set to be between the highest point and the lowest point of the surface temperature. It is a method of controlling and performing heated gas or heated gas blow and cooling blow. The thick line portion in this figure indicates the state where the shaped body is in contact with the surface of the mold, and the thin line portion indicates the state where the shaped body is removed. Here, although the preheating temperature of the sheet is not shown, it is naturally lower than the highest point, and if an example of a stretched PET material is given, the preheating optimum temperature is about 80 to 100 ° C., and the heat treatment optimum temperature is the surface temperature (shaped body). Interface temperature) of about 160-190 ° C., which is a big difference.
In the a zone shown in the figure, shaping and heating with a high-temperature gas are performed, in the b zone, cooling blow is performed, and in the c zone, release of the shaped body and placement of a new molding material are performed simultaneously. In addition, the a zone shaping and the high temperature gas contact may be performed by performing high pressure gas blowing while performing compressed air shaping with high temperature gas or vacuum shaping.
In the figure, further details of one cycle from a to c are shown separately as 1 to 5, but in 1 the surface temperature is naturally recovered by the high temperature of the back layer, and in 2 the back layer temperature. The surface temperature is increased only by the high temperature gas in 3 and 4 by the high temperature gas. 4 The surface temperature is cooled only by the cooling blow by both the back layer temperature and the cooling blow. Become.

  The modified pattern B (not shown) of the above method is a method of performing heating gas pressure air or heating gas blow by setting the steady-state temperature (S line) of the back layer to be the lowest point or below the surface temperature. It is. In this case, considerable cooling proceeds without performing cooling blow, but cooling blow can also be performed to perform cooling release in a short time. In this case, since the temperature rise to the heat treatment temperature depends exclusively on the heated gas, the heat treatment temperature may be relatively low, and it is suitable for molding in which cooling must be strengthened. Specifically, for example, it is not necessary to improve the heat resistance of the molded product so much. As the mold, a mold made of a surface layer material having a relatively small b value is suitable.

  In the modified pattern C (not shown) of the above method, the steady-state temperature (S line) of the back layer is set to be the highest point of the surface temperature or higher, and the cooling blow is performed after the pressure forming and heat treatment. How to do it. The temperature rise to the heat treatment temperature can be entrusted to heat transfer from below the surface of the mold, but the temperature can be raised in a short time by contacting the heated gas with the shaped body. On the other hand, since cooling depends exclusively on the cooling blow, it is suitable for molding in which the heat treatment temperature is increased and the cooling need not be so strong. Specifically, for example, the improvement of the heat resistance of the molded product is increased, the thickness of the molded product is large, and cooling is not so necessary for mold release. As the mold, the b value of the surface layer material may be relatively large, but when the surface layer material is relatively small, a material having a small layer thickness is suitable.

A representative pattern D different from the above method is shown in FIG. The method of this pattern is to irradiate the surface and / or the back of the shaped body by contacting heated gas with the molding surface and / or the back of the shaped body (the surface not in contact with the mold). To reach the top (T) of the molding cycle, and then bring the cooling gas flow into contact with the back of the shaped body and / or the surface to reach the bottom (B) point of the cycle. In this cycle, the material supply, shaping, heat treatment, cooling, and mold removal are continuously repeated at any appropriate point in the cycle. The feature of this method that is different from the above methods is that the measurement and management of the steady temperature inside the mold is not necessarily required, but is that the T and B points are controlled and managed to be constant. This is a method in which the surface temperature (or interface temperature, or the shaped object back surface temperature changed to this, etc. is measured, and the heating means and / or cooling means are adjusted.
Referring to FIG. 7 in detail, shaping and contact with a hot gas are performed in the zone a, cooling blow is performed in the zone b, and release of the shaped body and arrangement of new materials are continuously performed in the zone c. Is called. In addition, the shaping of the a zone and the high temperature gas contact may be performed by pressure forming with a high temperature gas or feeding a high temperature gas while performing vacuum shaping. In addition, the shaping may be performed with a gas pressure air at room temperature, and then a high temperature gas contact may be performed.
As another modification, for example, the heating means may be directly applied to the back surface (bare surface) to bring the temperature to a considerably high temperature, and then the material may be carried in, shaped, and further heated. Further, the cooling of the back surface may be stopped halfway, and the mold may be released, and further cooling means may be applied to the surface (bare surface).

  These patterns are categorized as representative examples, and the method is not limited and various modifications are possible. For example, (1) shaping or releasing is limited to the highest point or the lowest point of the temperature trajectory. You may start shaping at a point higher than the lowest point, release before reaching the highest point, start shaping after the highest point, or release before the lowest point. (2) A heating gas or a cooling gas can be blown directly on the mold surface in the absence of the shaped body to promote temperature regression. Alternatively, (3) the heating means application or cooling blow application after the shaping may be temporarily stopped at any point in time, and heat transfer from the mold may be used. It suffices if the T point and B point can be made constant.

<Supplementary information on temperature measurement>
In the patterns A to C, the temperature of the S-line is positively controlled for controlling 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. In the pattern D as well, the temperature of the mold becomes steady during repeated molding cycles without direct heating and cooling, and the value generally has a temperature gradient depending on the distance from the molding surface.
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 shown here. When shortening the molding cycle in units of seconds or less, it is necessary to increase the flow rate of the contact gas to increase the heat transfer coefficient as much as possible, and a large temperature gradient occurs in the thickness direction of the shaped body. It is. In addition, it is possible to control the above process by measuring the temperature from the back of the shaped body with infrared rays or the like, but it is not absolutely the temperature of the material. 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.

<Example 1>
<Molding device part of the present invention>
Use a pneumatic box equipped as shown in FIG. 7 (the heating part is attached to the pneumatic box with the dispersion delivery unit in close contact), combined with a mold storage box as shown in FIG. Mounted on top and bottom plates.
1) Gas heating device
A SUS box (effective projection size: 330 × 550 mm) was manufactured, and an aluminum perforated plate was pasted on the bottom to form a dispersion delivery unit, and the inside of the box was filled with aluminum particles. The aluminum porous plate had a thickness of 8 mm and had about 1100 through-holes with a diameter of 1.0 mm arranged in a uniform arrangement. In addition, the infrared radiation coating material (made by Okitsumo Co., Ltd.) was apply | coated to the lower surface.
The aluminum particles were substantially cylindrical and filled with a length of 3 mm and a diameter of 3 mm. The total area of contact with the compressed air body inside the box is 58800 cm ² , which is 30 times the projected area of the compressed air box.
2) Pressure Air Box A pressure air box having the same internal dimensions as the above gas heating device was made of carbon steel, and fixed and integrated with a high temperature gas generator via a heat insulating material as shown in the figure.
Inside, 12 cooling gas injection nozzles were arranged so as to be directly above the center of the arranged mold so that gas could be introduced from the outside. In addition, the exhaust slit pipe is arranged along the boundary line of the mold arrangement at a position close to the mold, and gas can be discharged to the outside by control. In addition, temperature sensors were placed in several spatial positions so that the air temperature could be measured.
3) Mold storage box and mold The mold storage box is made of carbon steel, and a fixed plate is provided inside the effective storage size 330 × 550 mm (area 1815 cm ² ) to fix the mold. An electric heater was attached. The mold is an aluminum base with a 0.3 mm epoxy resin coating (b value is 0.7) and a surface layer is formed. The molded product is a round dish with a diameter of 90 mm and a depth of 30 mm. Twelve sized 110 mm squares were stored. A thin wire thermocouple was exposed on the molding surface of the molding die, and the molding surface temperature (also the molding surface temperature of the shaped body) was measured.
<Overall configuration of molding apparatus>
The above apparatus is arranged and fixed between the top plate and the bottom plate of a press machine of a single wafer vacuum / pressure forming machine (pressure capacity 10 tons) having a sheet preheating oven, and compressed air for heating gas and cooling blow is controlled from the outside. I introduced it.
<Molding test and results>
Molding material Homopolyethylene terephthalate IV extrusion uniaxial
Stretched sheet (stretching ratio 2.3 times, non-heat-fixed product, thickness 2.3 mm)
Molding method and molding conditions

Gas delivery perforated plate 425 ° C
High temperature gas generator internal temperature 390 ℃
Mold base temperature 170 ° C
Mold surface temperature 155 ° C
Material sheet preheating temperature 85 ℃

2 seconds pressure forming, 2 seconds heat treatment (attainable surface temperature is 183 ° C)
4-second cooling blow (surface temperature at mold release 145 ° C)
Air temperature reached 280 ℃ in the compressed air box

Pneumatic forming pressure (static pressure) 0.35 MPa (gauge pressure)
Temperature rise (dynamic pressure) 0.15 MPa (gauge pressure)
Molded product performance Heat resistance of at least 150 ° C, high rigidity, transparency
A molded product with a high height was obtained. The heat resistance test was performed by immersing the molded product in rapeseed oil at 150 ° C. for 2 minutes, and there was no noticeable deformation.
Continuous molding simulation test
Assuming continuous molding, the heat-resistant molded product is fixed to the mold, and repeated for 2 hours by heating and air pressure, 2 seconds of heating blow, 4 seconds of cooling blow, and 2 seconds of rest for 1 cycle. However, stable and constant T values (maximum surface temperature reached) and B values (minimum surface temperature reached) were obtained. In addition, it confirmed that T value and B value could be arbitrarily set by changing each temperature of a shaping | molding die base temperature and a high temperature gas production | generation apparatus. Moreover, it was confirmed that it can be arbitrarily set by changing each process time and each blow strength in the cycle.

<Example 2>
<Molding device part of the present invention>
A gas heating section having the structure shown in FIG. 6 was manufactured, and the high-temperature compressed gas generated here was sent to a compressed air box containing a reflection-type dispersion delivery section having the structure shown in FIG. The compressed air box, the mold storage box, the heating unit, and the like were arranged in the same manner as in FIG.
1) Gas heating device A stainless steel-covered electric heater is housed in a carbon steel cylindrical container having an inner diameter of 300 mm and a length of 500 mm, and a band heater covered with stainless steel is also placed on the outside. A product filled with grains was produced, and compressed air was intermittently introduced and discharged from the outside in accordance with the molding cycle.
The total contact area with the air inside the apparatus is 203000 cm ² , which is 110 times the compressed air box projection area.
2) Reflector-type gas dispersion delivery unit The reflector is made of SUS, and a cartridge heater is provided inside so that it can be controlled to an arbitrary high temperature of 255 ° C. or higher. Further, as in Example 1, a heat-resistant black body paint having good infrared radiation efficiency was applied to the lower surface.
A high-temperature and high-pressure gas was introduced from the outside into the inside of the compressed air box, and jetted from four openings (slits) 300 mm long and 1 mm wide toward the ceiling reflector. In addition, the dimension of the reflecting plate was 330 * 550 mm which is the same as the inner dimension of the compressed air box.
3) The same structure as that of the previous example was used except that a high temperature gas introduction path was provided on the outer side of the compressed air box, and it was connected and fixed to the reflector.
4) It was comprised with the same thing as a shaping | molding die storage box and a shaping | molding die previous Example.
<Overall configuration of molding apparatus>
Each apparatus was arranged according to the previous example except that the same molding machine as in the previous example was used and the gas heating apparatus was placed outside the press machine.
<Molding test and results>
Temperature setting of gas heating device 440 ° C
Reflector temperature setting 440 ° C
The other settings were the same as in the previous example, and almost the same results were obtained.
Similar results were obtained in the continuous simulation test.

(Utility using this molding equipment)
Thermoforming using the mold of the mechanism of the present invention has the following effects.
(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 thermoformed product having excellent mechanical strength such as heat resistance, transparency, and rigidity can be efficiently obtained by thermoforming a crystalline resin stretched sheet, for example, a stretched PET sheet material as described above. Can be produced. Further, a material-saving molded product can be obtained by utilizing rigidity.
(3) By reflecting the measurement result of the fluctuating temperature and adjusting or controlling the heating condition and the cooling condition, the optimum product and the shortest cycle can be easily realized and stable control can be performed. Moreover, it can shift to stable production conditions in a short time.
(4) Uniform molded products and molded products with few variations can be efficiently produced by molding many pieces.
(5) A wide variety of molds or molding materials can be selected and used for molding.
(6) Production can be performed while saving energy consumption.
(7) The apparatus of the present invention can be applied to a wide range of materials other than a stretched sheet of crystalline resin, such as an unstretched material, such as a CPET material.

1 Press machine top plate 2 Press machine bottom plate
3 Mold storage box 4 Pressure box
A cold compressed gas A 'hot compressed gas
B Exhaust C Cooling gas
DESCRIPTION OF SYMBOLS 11 Heat insulating material 12 Heat insulating material 13 Volatile liquid injection nozzle 14 Infrared temperature measurement probe 31 Vacuum suction exhaust port 32 Cavity 33 Molding type fixed temperature control board 34 Heater
35 Vacuum exhaust passage 40 Dispersion delivery part of gas 41 Gas injection nozzle for cooling
42 Cooling gas inlet tube
43 Control valve
44 Exhaust slit tube 45 Exhaust conduit 46 Control valve
50 Gas heating section
51 Compressed gas inlet
52 Manifold 53 Heater
54 Metal Grain or Metal Porous Material 56 Cylindrical Outer Shell 57 Discharge Port 58 Opening / closing Valve 59 Heat Insulating Material 60 Mold 61 Molding Surface Layer 62 Back Layer 63 Vacuum Exhaust Hole 64 Vacuum Exhaust Passage 65 Heating Medium Passage 71 Reflector
72 Heater 73 Reflecting surface 74 of reflector Reflective gas introduction pipe 75 Injection slit pipe 76 Introduction compressed gas selection valve 77 Introduction compression gas selection valve 81 High temperature compressed gas distribution panel 82 High temperature gas introduction pipe 83 Manifold 84 Heater 85 Dispersing nozzle 91 Injection Reflector 92 Target reflector 95 High-temperature gas introduction tube 96 Slit tube 100 Thermoplastic resin sheet (resin sheet)

Claims (9)

Molding of a resin sheet configured to sandwich a thermoplastic resin sheet between a compressed air box and a mold storage box having a mold, and molding a thermoplastic resin sheet by introducing compressed gas into the compressed air box A device,
The compressed air box is provided with a dispersion delivery unit that distributes and delivers high-temperature compressed gas, and a cooling unit that has an injection nozzle that injects a cooling gas toward the mold storage box.
The dispersion delivery unit sends compressed gas to the thermoplastic resin sheet through a gap formed between the outer shell of the compressed air box and the injection nozzle,
Furthermore, the resin sheet shaping | molding apparatus provided with the heating part which heats the compressed gas supplied to the said dispersion | distribution delivery part.   2. The molding of a resin sheet according to claim 1, wherein the compressed air box has a discharge hole that communicates with the outside a closed space formed between the mold storage box and the compressed air box in a sandwiched state of the thermoplastic resin sheet. apparatus.   The said heating part is a resin sheet shaping | molding apparatus of Claim 1 or 2 provided with the thermal storage body which has many clearance gaps used as the flow path of compressed air, and the heating heater which heats the said thermal storage body.   The said heating part is a shaping | molding apparatus of the resin sheet in any one of Claim 1 to 3 integrated with the said dispersion | distribution delivery part.   The apparatus for molding a resin sheet according to any one of claims 1 to 4, wherein an infrared emissivity of a surface of the compressed air box facing the mold storage box is 0.8 or more.   The molding apparatus of the resin sheet in any one of Claim 1 to 5 provided with the liquid spraying part which sprays a volatile liquid toward the thermoplastic resin sheet after shaping. The said mold is a heat | fever permeability (kJ / m < ² > s < ^1/2 > K) of the material which comprises the molding surface of a thermoplastic resin sheet, and is 0.01-15. Resin sheet molding equipment.   The said compressed air box is a resin sheet shaping | molding apparatus in any one of Claim 1 to 7 provided with the infrared thermometer which measures the surface temperature change of the thermoplastic resin sheet in a shaping | molding cycle continuously without contact. A resin sheet molding method using the resin sheet molding apparatus according to any one of claims 1 to 8, wherein a shaping step for shaping a thermoplastic resin sheet, and a heat treatment at a temperature higher than the shaping step. And a heat treatment step for forming a resin sheet.

Images