WO2013015253A1 - Thermoforming device and forming method - Google Patents

Abstract

A thermoforming device whereby, in the process from thermoform shaping to mold release, a shaped article can be only rapidly heated or both rapidly heated and then subjected to a cooling step, making it possible, in particular, to rapidly, efficiently, and continuously carry out thermoforming in which mold release is performed by carrying out a heat treatment at a high temperature equal to or greater than a pre-heating sheet temperature prior to shaping, the thermoforming device being characterized in comprising: a male/female forming die which is provided with a gas injection hole on a forming surface of either a male die or a female die and comprises a die (hereinafter referred to as an "injection die") endowed with a function for injecting a cooling gas and/or a heating gas and a space-shaping function for diffusing the injected gas over the entire surface of a shaped article, as well as another die (hereinafter referred to as a "holding die") corresponding thereto; and a means for introducing compressed gas into the injection die. The thermoforming device is further characterized by being configured such that the introduced gas is injected from the injection-die-forming surface, which is at a distance away from the shaped article, following the shaping of a resin sheet, and the shaped article held by the holding die is heated or cooled.

Description

Apparatus and method for thermoforming

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

The thermoforming method is a method in which a preheated thermoplastic resin sheet or film is formed on a mold by pressing or vacuuming and then released, but in normal thermoforming, the shaped body is cooled by a low-temperature mold. It is released in the state. As a mold material, a material such as aluminum or zinc alloy that is lightweight and has good workability and good thermal conductivity is used, and it is often continuously formed by natural heat dissipation. However, in particular, if it is desired to adjust the temperature, the jacket provided inside the mold is cooled through a heat medium. On the other hand, cheap and easy-to-process materials such as wood and plastic may be used, but these are not durable and difficult to control temperature, causing problems such as heat accumulation, making them suitable for continuous mass production. However, its use is limited to sample trial production or small-scale production on a single-wafer molding machine.

And as a special molding method, when you want to heat or cool the shaped body arbitrarily during the molding cycle, change the heating medium in the middle of the heating medium passed through the jacket, or adjust the temperature of the shaped body separately It is performed to move to the mold. However, with such a method, a molded product that has been subjected to a desired heat treatment cannot be produced continuously at high speed and efficiently.

As a specific thermoforming method that requires special heating or cooling, (1) Japanese Examined Patent Publication No. 56-7855 is a method of thermoforming a polyester sheet by uniaxially stretching and heat-shrinking the sheet, Although a method of heat setting by using hot air at the time of molding is disclosed, the heat treatment takes a very long time and is not practical.

Also, (2) Japanese Patent Publication No. 5-45412 discloses a method of performing thermoforming and heat treatment using a biaxially stretched and heat-shrinked sheet under specific conditions. 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 operation.

In addition, (5) Japanese Patent Publication No. 7-102608 shows a method of molding with a high-temperature female mold, taking it into a low-temperature male mold fitted to the mold, cooling it, and releasing the mold. It may be said that the method is the same as (4), and deformation and wrinkling of the molding become a problem as well, and it is difficult to apply to a molded product having an offset or undercut. In addition to these examples, in the molding of so-called CPET as in (4) and (5), if molding is performed with a high-temperature mold from the beginning, the molding material does not slide smoothly on the mold surface, and thus unevenness such as waves and unevenness is generated. There is also a problem that a pattern is likely to appear. To avoid this problem, a process of forming with a low temperature mold and then shifting to a high temperature mold is known, but this is also complicated.

Further, (6) Japanese Patent Laid-Open No. 06-166099 also discloses a method of molding a specific molding material by molding one of the male and female molds at a high temperature and fitting another cold mold to cool the molded body. . However, this method causes problems such as wrinkle generation and mold removal related to molding shrinkage, and a molded product having an offset portion cannot be obtained.

Further, (7) A method disclosed in Japanese Patent No. 4057487 relates to thermoforming of a crystalline resin, and a sheet preheated in contact with a heating plate is compressed and shaped with hot air passing through the heating plate and a molding die. Then, cooling air jetting means prepared separately is carried in and cooled, but this heating plate is adjusted to an appropriate temperature for sheet preheating, and heated air is supplied from behind to produce heated and compressed air. In this case, the heated gas is cooled in a conduit passing through the hot plate, and a very high temperature gas must be passed through the heat treatment, in which case the hot plate temperature is localized and non-uniform, and the material sheet is Local overheating tends to hinder good molding. Further, the disclosed cooling means cannot cool a large area uniformly and efficiently. Also, heat from the high temperature gas is easily dissipated into the mold, and the sheet cannot be easily heated to a high temperature in a short time, and high speed molding cannot be performed.

Further, (8) US Pat. No. 5,119,176 proposes a method in which a resin sheet once biaxially stretched is heated and thermally contracted on a male mold. Although this method may improve the formability, a sufficient orientation effect cannot be used, and there are many molding restrictions such as a shape having an offset portion. There is no disclosure of rapid heat setting and cooling mold release.

Note that (9) JP2011-245443, JP2011-245644,
Japanese Patent Application Laid-Open No. 2011-245650 and Japanese Patent Application Laid-Open No. 2011-245651 relate to a molding method and a mold that are related to the present application, and are made by the same inventors as the present invention. The present inventor has further filed 10 applications mainly for the molding apparatus and the like for carrying out these methods. This application is based on the priority of some applications related to these molding apparatuses and the like.

Non-Patent Documents 1 and 2 below show known typical fitting molds and plug assist molds that are compared with the male and female molds of the novel structure that constitute the present invention.

Japanese Patent Publication No.56-7855 Japanese Patent Publication No. 5-45412 Japanese Patent Publication No. 60-031651 Patent 2532730 Japanese Patent Publication No. 7-102608 Japanese Patent Laid-Open No. 6-166099 Japanese Patent No. 4057487 US Patent 519176 JP2011-245643 JP2011-245644 JP2011-245650 JP2011-245651

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 molding apparatus and a molding method that can perform thermoforming for releasing at high speed and efficiently continuously, and obtain a molded product in a uniform and good state.

(1) In a resin sheet thermoforming apparatus, a function of injecting at least one of a cooling gas and a heating gas by providing an injection hole on a molding surface of either a female mold or a male mold that can be fitted; A male-male mold comprising a mold (hereinafter referred to as an injection mold) having a space forming function for diffusing gas over the entire shaped body, and another mold (hereinafter referred to as a holding mold) corresponding thereto, and the gas injection A means for introducing compressed gas into the mold, and heating or cooling the shaped body held by the holding mold by injecting the gas from the injection molding surface at a distance away from the shaped body after shaping the resin sheet A molding apparatus for a thermoplastic resin sheet configured as described above is provided.

The male and female molds do not necessarily need to be closely fitted, and may be fitted so as to have a space even through a shaped body. Further, the molding surface for injecting the gas does not necessarily come into contact with the resin sheet in the molding process, and even when there is no contact process, it is referred to as a molding surface.
In the present invention, “molding” indicates the entire molding process from preheating to mold release, and “compressed air molding” indicates a molding method including a “compressed air forming” process using compressed air. In addition, compressed air is providing a gas pressure. Further, the “shaped body” indicates a molded product before release in a state of being held in the mold.

(2) The molding apparatus according to (1) is provided, which has means for holding the shaped body in close contact with the molding surface of the holding mold.

(3) The holding mold has at least a molding surface made of a material having a thermal permeability (b value) (kJ / m ² s ^1/2 K) of 0.01 to 25. The thermoforming mold according to the above (1) or (2) is provided.
The definition of the molding surface here excludes a coating agent for lubrication, mold release, etc., paint or plating of 50 μm or less applied to the molding surface.
The heat permeability of the surface layer forming material is preferably 20 or less, more preferably 15 or less, and still more preferably 10 or less.

(4) The shaped body holding mold comprises a surface layer made of a material having a heat permeability (b value) of 20 or less and a back body made of a material having a heat permeability (b value) larger than that of the surface layer. The thermoforming mold according to any one of the above (1) to (3), which is characterized in that it is provided.

(5) The molding apparatus according to any one of (1) to (4) above, wherein the holding mold is provided with means for controlling the temperature of itself.
More preferably, the temperature control means is added to the back body to control the surface layer temperature.

(6) The holding mold is provided with means for controlling or automatically adjusting the surface layer temperature by being in close contact with or behind the surface layer made of a material having a thermal permeability (b value) of 15 or less. The molding apparatus according to any one of the above 1) to (5) is provided.

(7) In the injection type, in addition to a mechanism for injecting gas from the injection hole, a mechanism for injecting the injected gas from a suction hole provided separately from the injection hole and exhausting it to the outside is provided. The molding apparatus according to any one of (1) to (6) above is provided.

(8) In the above injection mold, injection can be performed by changing the type of gas during one molding step, and the above “injecting mechanism” functions as a mechanism for exhausting from the middle, and the above “exhaust mechanism” The molding apparatus according to any one of the above (1) to (7), which is configured to function as a mechanism for injecting from the middle.

(9) The above-described male and female molds are formed so as to form a compressed air space that is closed when the resin sheet is sandwiched between them, and gas can be ejected from the above-mentioned ejection mold so that compressed air shaping can be performed. The molding apparatus according to any one of (1) to (8) above is provided.

(10) A resin sheet molding method using the molding apparatus according to any one of (1) to (9) above, wherein the resin sheet is preheated, shaped, and heat treated at a temperature higher than the sheet preheat temperature. The present invention provides a method for forming a thermoplastic resin sheet that performs a heat treatment step and a cooling step as necessary.

(11) As a method for heat-treating the shaped body at a high temperature, at least one of 1) a method of ejecting a heated gas from the gas ejection mold, or 2) a method of heating and using the holding mold is used. The molding method according to (10) is provided.

The apparatus configuration using the special male and female mold of the present invention has the following effects.
1) Molding can be performed by combining press shaping or male assist (plug assist) shaping capable of powerful shaping, and high-speed heating and / or cooling.

2) A specific simple mechanism can be added to enable pneumatic forming or vacuum forming, and it is also possible to form a molded product having an offset portion that cannot be achieved by a known male and female mold.

3) By performing gas injection at a position close to the shaped body, the shaped body can be subjected to strong blow heating and / or blow cooling, and the molding cycle with heat treatment can be shortened.

4) Gas injection can be performed at a uniform distance from each part of the shaped body, uniform blow heating or blow cooling is possible, and a uniform molded product can be obtained.

5) By using a specific material or a specific structure using a specific material for either of the male and female dies, heating or cooling of the shaped body with air having a small heat capacity can be performed efficiently.

6) Due to the effects described above, the process of pre-heating and releasing the resin sheet at a high temperature, which is significantly higher than the pre-heating temperature of the resin sheet, and then cooling and releasing at a very high speed. Can be run continuously, efficiently and stably.

7) The shortening of the molding cycle and the efficiency increase the energy-saving production, and the applicable molding material objects can be expanded.
Specific applications include: a) molding involving heat setting of a stretched sheet of a crystalline resin such as PET, b) molding involving crystallization of a crystalline resin sheet such as a crystal nucleating agent-added PET (CPET), or In addition, c) heat treatment molding can be proposed in which the residual stress distortion associated with SPPF molding (solid phase high pressure molding) of polypropylene is relaxed. d) Residual distortion is eliminated even by thermoforming of amorphous (amorphous) resin, and a product with high dimensional accuracy can be obtained.

8) In addition, products that have been limited to special applications can be made into general-purpose products. For example, stretched PET efficiently produces thermoformed products having excellent mechanical strength such as heat resistance, transparency, and rigidity. Here, it is possible to use the rigidity to reduce the thickness of the molded product to save material, and to replace the commercially available normal molded product by high-speed molding equivalent to the normal molding obtained above.

It is sectional drawing which shows the structural example of the shaping | molding apparatus of this invention. It is sectional drawing which shows the example of the male-and-male shaping | molding die used for this invention. It is sectional drawing which shows another example of the male-and-male shaping | molding die used for this invention. It is sectional drawing which shows another example of the male-and-male shaping | molding die used for this invention. It is sectional drawing which shows another example of the male-and-male shaping | molding die used for this invention. It is sectional drawing which shows an example different from the upper figure of the holding | maintenance type | mold used for this invention. It is sectional drawing which shows another example from the upper figure of the holding | maintenance type | mold used for this invention. It is sectional drawing which shows another example from the upper figure of the holding | maintenance type | mold used for this invention.

<Overall configuration of molding apparatus>
The thermoplastic resin sheet molding apparatus of the present invention is configured by incorporating a male and female molding die having a specific configuration into a thermoforming machine. The thermoforming machine is equipped with male and female mold separating means such as a press machine, preheating means for resin sheet of molding material, compressed gas introducing means, vacuum suction means, molding material conveying means, molded product unloading means, etc. use. Note that it is preferable that both the compressed gas introducing means and the vacuum suction means are aligned, but there are cases where only one of them is sufficient. The resin sheet preheating means may employ any known method such as indirect heating using a heating oven or the like, or direct heating in contact with a heating plate. In the thermoforming method, a mold called a male and female mold (also called a fitting mold or a matched die) is sometimes used. However, in the present invention, a male and female mold having a new specific configuration is used. .

As a first invention belonging to the present invention, in a thermoforming apparatus for a resin sheet, at least one of a cooling gas and a heating gas is provided by providing an injection hole in a molding surface of either a female mold or a male mold that can be fitted. A male and female consisting of a mold (hereinafter referred to as an injection type) having a function of injecting a gas and a space forming function for diffusing the injected gas over the entire shaped body (hereinafter referred to as an injection type) and a corresponding other type (hereinafter referred to as a holding type) Using a molding die, and equipped with a compressed gas introduction means to the gas injection mold, and after the resin sheet is shaped, the gas is injected from the injection molding surface at a distance away from the shaped body, and the holding mold is used. It is comprised so that the shaped body currently hold | maintained may be heated or cooled.

There are several methods for providing the above space forming function. For example, as method A , the gap between the female and male molds is approximately the thickness of the molding material sheet, and the gas injection mold is slightly separated after shaping. Thus, it can be provided by forming a molded body shape that can form a space for gas injection between substantially the entire surface of the shaped body. In Method B , the gap between the male mold and the mold is made larger than the thickness of the molding material sheet, the female mold is brought close to the male mold with the molding material sheet sandwiched, and the vacuum shaping action from the shaped object holding mold side is also shared. Actuate to form a space for gas injection. In Method C , the gap between the female male mold is made larger than the thickness of the molding material sheet, and a bank (closed wall) is provided so that a closed space is formed when the female male mold is joined, and gas injection is performed. The shaping action by the compressed air from the mold is caused to work together to form a space for heating or cooling injection. Note that the closed space forming bank or the like may be provided in any of the female and male molds, or may be inserted as an independent member when both molds are approaching.

In addition, in the case of the method B and the method C, it may carry out by vacuum shaping and may be made to approach a gas injection type | mold later, and this is also contained in the method of this invention.
The compressed gas introducing means is a gas compressor, a compressed gas heating device, and the like arranged outside the mold, and equipment that introduces the gas and appropriately supplies it into the mold. One of the female mold and the male mold is fixed to the top plate of the press machine, the other is fixed to the bottom plate directly below it, and at least one of the top plate and the bottom plate is movable up and down. Allows the mold and female molds to be separated.

The resin sheet for molding is preheated and brought between the female mold and the male mold, and the sheet is sandwiched by lowering one side or the other, and is subjected to shaping, heat treatment, cooling, and release.
The heat treatment of the shaped body is performed by 1) jetting of heated gas from the injection mold, or 2) heating by the preheated temperature-controlled shaped body holding mold. The shaped body is cooled by 1) a relatively low temperature gas injection from the injection mold, or 2) a holding mold that is controlled to a relatively low temperature.
The shaped body is released when the gas injection mold and the holding mold are largely separated after the cooling step.

As the above-mentioned injection gas, any one can be used as long as it is harmless to the human body and the molded product such as air, nitrogen, carbon dioxide, etc., and water is mixed into these in order to enhance the heating effect or the cooling effect. In order to enhance the cooling effect, fine droplets of a volatile substance, for example, a volatile substance such as alcohol may be mixed therein.
In addition, even if the said injection gas is a gas for cooling or a gas for heating, you may utilize the same thing for compressed air shaping.

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 structure and operation of the above-described injection type will be described in detail in the subsequent <About injection type> column, and the structure and operation of the holding type will be described in detail in the subsequent <About holding type> column.

As a second invention belonging to the present invention, it is preferable to provide means for holding the shaped body in close contact with the molding surface of the holding mold.
As specific means, a) a vacuum exhaust hole penetrating from the molding surface of the shaped body holding mold to the back is provided for vacuuming, and b) a vacuum exhaust narrow groove is provided on the molding surface of the shaped body holding mold for vacuum suction. C) Providing a partial offset portion of the molded product, d) Maintaining a certain level of compressed air pressure through the heat treatment process and the cooling process, e) Making the male mold a holding mold, and utilizing molding shrinkage There is a method of holding. a) and b) are the simplest methods.

A ninth invention belonging to the present invention, wherein the male and female molds are formed so as to form a compressed air space that is closed when the resin sheet is sandwiched, and a gas is ejected from the ejection mold to form a compressed air To be able to Specifically, a closed wall (bank) may be provided around either type of male or female. Details will be described with reference to FIG.

A specific example of the apparatus configuration of the present invention will be described with reference to FIG. Reference numeral 40 denotes an injection type (male type), 60 denotes a holding type (female type), 50 denotes an injection space (gap), and 110 denotes a shaped body. Although not shown in the drawing, the injection mold (male mold) 40 and the holding mold (female mold) 60 are respectively fixed to the top plate and the bottom plate of the press machine and are vertically movable. The resin sheet preheated in the preheating oven is guided between both molds, and can be shaped by bringing both molds close to each other.

The injection type (male and female) 40 is configured to inject compressed gas or heated compressed gas introduced from an external device into the injection space (gap) 50 from the spout injection hole 45 provided in the molding surface 44. In this drawing, the other parts of the molding machine, the compressed gas or heated compressed gas generating device, etc. are not shown. The holding mold (female mold) 60 heats a plurality of main bodies composed of a surface layer 61 made of a material having a relatively small heat permeability and a back layer (back body) 62 made of a material having a relatively large heat permeability. This is fixed to a collecting plate 66 provided with a medium passage 65. *

In this figure, the injection mold 40 has a shape similar to that of the molded product and is smaller than that. When combined with the injection mold, the injection mold 40 has a dimension that forms a gap larger than the resin sheet thickness. In addition, gas is injected into the space 50 and the injected gas is exhausted through the exhaust passage 46 in a state where the shaped body is formed and held by evacuation from the holding die (female die) 60 side. .

At least two molding methods are possible using the male and female molds of this mechanism. One method is to raise the temperature of the surface layer 61 or the molding surface of the holding die (female die) 60 to a necessary heat treatment temperature and inject non-heated low-temperature gas from the injection holes 45 after the shaping heat treatment. Then, the shaped body is cooled and released. The other is that the back body 62 of the holding mold (female mold) 60 is adjusted to a temperature not higher than the upper limit of mold release capability, and a high-temperature gas heated from the gas injection hole 45 at the same time as shaping or after shaping. This is a method in which the shaped body is heated and heated, the injection is stopped, and the shaped body is cooled and released by heat transfer from the back body 62 via the surface layer 61.

The heater 47 warms the molding surface 42 to about the preheating temperature of the resin sheet so as not to cool the preheated sheet. However, for this purpose, there is a method in which the molding surface 44 is covered with a heat insulating material such as cloth without using the heater 47.
In addition, when injecting heating gas with this apparatus, you may heat the whole injection body 40 with the heater 47 at high temperature so that introduction gas may not be cooled. In this case, it is preferable to cover the molding surface 44 with a heat insulating material such as cloth so as not to overheat the resin sheet.

A known method using a male and female mold to be compared with the present invention is disclosed in Japanese Patent Publication No. 7-102608 (Patent No. 2141026) and Japanese Patent Publication No. 06-16609. The details are as described in the “Technical Background” section. However, if further described, none of the above methods has the gas injection mechanism as described above. It does not have a structure that uniformly contacts the entire shaped body.

The inventor of the present invention has filed a prior application for a mold and a molding method in Japanese Patent Application Laid-Open Nos. 2011-245463, 2011-245644, 2011-245650, and 2011-245651 in almost the same field as the present invention. 5) Japanese Patent Application No. 2011-41294, 6) Japanese Patent Application No. 2011-165067, 7) Japanese Patent Application No. 2011-165068, 8) Japanese Patent Application No. 2011-165069, 9) Application for Japanese Patent Application No. 2011-20614, 10) Japanese Patent Application No. 2011-206515, 11) Japanese Patent Application No. 2011-206516, 12) Japanese Patent Application No. 2011-254541, 13) Japanese Patent Application No. 2011-254640. This application is made on the basis of the priority of 8), 11) and 13).
Further details of the invention will now be described for each component of the invention.

<About injection type>
As described above, the injection type is provided with a gas injection hole, an injection space forming function, and compressed gas introduction means for injecting and diffusing at least one of the cooling gas and the heating gas on the surface. The injection space forming function and the gas injection means are described above. Although not limited to these injection-type mechanisms, the following four modes will be sequentially described.

In the first embodiment , gas is injected from the injection mold surface, and the injected gas is exhausted along the injection space (gap). In this case, the method for forming the injection space may be a male / female complete fitting method or an incomplete fitting (hereinafter also referred to as loose fitting) method.
This embodiment has been described above with reference to FIG.

The second form is a seventh invention belonging to the present invention . That is, in the injection type, in addition to the mechanism for injecting gas from the injection hole, a mechanism for inhaling the gas injected into the injection space (gap) from the intake hole separately provided on the injection surface and exhausting it to the outside is provided. To the configuration.
In this case as well, as in the first embodiment, the method for forming the injection space may be a male and female complete fitting method or a loose fitting method. With this configuration, a wider target area can be efficiently and uniformly heated or cooled so that it can be used preferably.

An example of the gas injection type of the second embodiment will be described with reference to FIG. The injection mold 40 in this figure is similar in shape to the molded product and slightly smaller than that, and when combined with the holding mold (female mold) 60 side, the injection mold 40 has dimensions that allow fitting and shaping with a gap close to the thickness of the coarse resin sheet. It has been. Further, when only 40 is lifted slightly after shaping, it is formed into a shape that can form an injection space 50 having a substantially uniform gap. This figure shows a state in which the injection mold 40 is lifted slightly after the resin sheet is fitted and shaped by the male and female molds, gas is injected from the injection mold 40, and the injected gas is exhausted through the exhaust passage 46. Yes. The shaped body is vacuum-sucked and held by the holding mold (female mold) 60. The holding mold (female mold) 60 in this figure will be described later separately.
In the configuration of this figure, the non-heated gas may be injected as in the case of FIG. 1, or the heating high-temperature gas can be similarly used.

FIG. 3 shows another example of the above injection type. In this example, in addition to the gas ejection holes, a plurality of suction holes are provided for external exhaust of the ejection gas. The relationship between the female type and the male type may be the case of complete fitting as shown in FIG. 1 or the case of loose fitting as shown in FIG. FIG. 3 shows a state in which the gas is injected into the injection space 50 formed after shaping and the gas is exhausted to the outside. The injection mold 40 of this figure is composed of an injection port 41 and an exhaust port 51. The injection body injects the introduced compressed gas from injection holes 45 provided in the molding surface 44, and the exhaust body is provided separately in the same surface layer 44. From the suction hole 55, the injected gas is sucked, led to the outside, and exhausted. The heater 47 is for preheating the molding surface 44 to an appropriate shaping temperature. The holding mold (female mold) in this figure is the same as that described in FIGS. 1 and 2 and will be described later.
It is also possible to change the configuration so that the upper injection port 41 is an exhaust port and the lower exhaust port 51 is an injection port while leaving the basic structure as it is.

The third embodiment is an eighth invention belonging to the present invention . That is, in the above injection mold, it is possible to perform injection by changing the type of gas during one molding step, and the above “injecting mechanism” functions as a mechanism for exhausting from the middle, and the above “exhaust mechanism” Is configured to function as a mechanism for injecting from the middle.

The third embodiment has substantially the same structure as the second embodiment, and injects and exhausts the heated high-temperature gas introduced from the outside in the preceding process in the same manner, and the relatively low temperature in the subsequent process. Injects and exhausts air from the injection holes. In this case, it is preferable that the preceding process is performed in the same manner, and the gas injection mechanism is switched to perform the work of the intake and exhaust and the mechanism of the intake and exhaust is performed to perform the work of gas injection in the subsequent process. It is preferable to adjust the temperature of each contact member so as to be suitable for low-temperature gas injection. However, this does not preclude injecting heated high-temperature gas and low-temperature gas from the same injection hole, and intake and exhaust from the gas intake hole. Also in this case, the method for forming the injection space may be a male / female complete fitting method or a loose fitting method. *

The injection type of the third form will be further described. In this aspect, the molding surface has a heating gas injection hole and a cooling gas injection hole, and during the heating gas injection, the cooling gas injection hole operates as the intake hole, and the cooling gas During the injection, the one configured such that the injection hole for the heating gas operates as the intake hole is used. A specific example is shown in FIG. In the configuration of this figure, as in the case of FIG. 3, both the complete fitting and the loose fitting are included. FIG. 3 shows a state in which the gas is injected into the injection space 50 formed after shaping and the gas is exhausted to the outside.

4 includes an injection port) 41 and an exhaust port 51. The hot compressed gas introduced by the injection port 41 is injected into the injection space 50 from the injection hole 45, and the exhaust port 51 sucks the injection space 50 gas. The air is sucked from the hole 55 and led to the outside to be discharged. Then, at any appropriate time, these functions are changed, the non-heated compressed gas introduced into the exhaust port 51 is injected from the intake hole 55, and the injected gas is sucked and guided from the injection hole 45 and exhausted to the outside. It is a mechanism to do.
The above basic structure can be left as it is, and the upper injection port 41 can be used as an exhaust port and the lower exhaust port 51 can be used as an injection port.

By this mechanism, it is possible to efficiently heat-treat the shaped body held by the shaped body holding mold by injecting the high-temperature compressed gas, and then efficiently cool the shaped body by injecting the non-heated compressed gas.
In addition, vacuum shaping may be used in combination with vacuum shaping, or may be used in combination with compressed air shaping. When using compressed air shaping, injection of hot compressed gas may be used, or unheated compressed gas may be used. However, it goes without saying that it is desirable to close the valve on the exhaust side when using compressed air shaping.

The fourth embodiment is the ninth invention belonging to the present invention . That is, the above-described male and female molds are configured to form a compressed air space that is closed when the resin sheet is sandwiched between them, and to perform compressed air shaping by ejecting gas from the ejection mold.
The injection mechanism and the form of exhaust may be any of the first to third. A bank (closed wall) is provided so that a closed space is formed when the female and male dies are joined. In this embodiment, male and female loose fitting is performed, and compressed air shaping can be performed. In addition, when this is performed by the injection / exhaust mechanism of the first aspect, the female / male mold is separated again to perform gas injection / exhaust. In addition, this bank (closing wall) does not necessarily need to be provided in the injection type, and may be provided in the holding type. Further, it may be inserted in the middle of molding as an independent member without being attached to the mold. Alternatively, the injection type or the holding type may be stored in a storage box having a high outer wall, and the outer wall may be a bank (closing wall). In addition, it is preferable to use a sealing material such as silicone rubber for a part of the bank.

FIG. 5 shows a specific example of the fourth embodiment. The configuration of this figure includes a bank (closing wall) 51b, and other names and operation mechanisms are the same as those in FIG. When the bank 51b joins the female mold and the male mold with the resin sheet in between, a closed space is formed. This figure shows that either the high-temperature gas or the non-heated gas is compressed and shaped, and either the high-temperature gas or the non-heated gas can be injected.
Note that the bank (closing wall) 51b does not necessarily have to be able to be completely closed, and it is sufficient if the pressure can be maintained to the extent that compressed air shaping is possible.
In addition, in the structure of this aspect, you may perform vacuum shaping not only in compressed air shaping. Moreover, you may comprise so that either heating injection or cooling injection may be performed independently.
The above basic structure can be left as it is, and the upper injection port 41 can be used as an exhaust port and the lower exhaust port 51 can be used as an injection port.
The formation of the bank (closing wall) as described above can be applied to any injection type as long as it is loosely fitted regardless of the injection or exhaust mechanism.

Apart from the above, various modes of the injection type are shown . Either can be used suitably.
1) An exhaust enhancement means for suction exhaust such as a flower may be added to the injection type exhaust body of each aspect described above, which can be suitably used.

2) When using heated compressed gas, you may make it the structure which introduces normal temperature compressed gas and heats inside an injection type, and it can use it suitably.

3) It is also preferable to spray or spray a volatile liquid such as water or alcohol in combination with the compressed gas injection for cooling the shaped body. In this case, the injection hole may be used also as the gas injection hole, or another independent injection or spray nozzle may be provided, which can be suitably used.

4) The compressed gas used in the cooling step of the shaped body is preferably lower than room temperature, and the compressed gas may be cooled by immersing it in the dry ice lump, or mixed with dry ice powder. You may spray, or you may make it the structure which cools using the means of adiabatic expansion, and these can be used suitably.

5) In the above aspects 2 and 3, not only one kind of injection gas but also different temperatures are prepared. For example, the apparatus is configured to inject a high temperature gas first and then a low temperature gas. May be.

6) It is possible to carry out the three steps of shaping heat treatment cooling at once with compressed gas injection at one temperature. Note that a mechanism may be employed in which a specific amount of exhaust is always performed without providing a valve. In that case, there is no problem if the apparatus is set in anticipation of the pressure drop when accompanied by compressed air shaping.

7) In the case where a foamable resin sheet is used, the male and female molds may be configured with a gap thicker than the material sheet, or the structure may be configured such that the gas injection mold is evacuated temporarily in the shaping process. Can be configured.

8) As a special mode of the injection mold, the molding surface is heated to a high temperature of 200 ° C. or higher, preferably 250 ° C. or higher, more preferably 300 ° C. or higher to emit infrared rays, which is preferably used for heating the shaped article. be able to. Therefore, it is desirable to set the infrared emissivity to 0.8 or more by a method such as application of black body paint on the molding surface. In this case, the resin sheet must be shaped without contact on the molding surface.

The injection type used in the configuration of the present invention has the following effects.
1) Gas can be sent out continuously at any time, and the process can proceed quickly from shaping to the next heating or cooling process. 2) Heating or cooling by gas injection can be uniformly and powerfully applied to all molding surfaces. 3) The entire molding apparatus can be simply configured.

<Holding type>
The holding mold used as the apparatus component of the present invention is not particularly limited as long as it includes necessary elements for known thermoforming such as a vacuum exhaust hole.
However, as a third invention belonging to the present invention, as the holding mold used as a component of the apparatus, at least molding is performed with a material having a thermal permeability (kJ / m ² s ^1/2 K) of 0.01 to 25. It is preferable to use one having a working surface formed. However, plating or coating of 50 μm or less for the purpose of protection or lubrication is not subject to the restrictions on the forming material of the molding surface.

The molding die may have a single structure made of the above material, or a composite structure having the above material as a surface layer. In the case of being composed of a single material, when it is composed of a single material having a thermal permeability of 0.01 to 10, it can be suitably used without adding a temperature control means. Further, when it is composed of a single material having a heat permeability of 2 to 25, it can be suitably used by adding a temperature control means.

Examples of materials having a thermal permeability within the above range include plastics, ceramics, and a small number of selected metal materials. These include aluminum materials and zinc alloy materials that are commonly used as thermoforming molds. Is a value smaller than. Examples of materials having a preferred range of heat permeability can also be selected from Table 1. However, the notation is shown for reference to general substances or objects, and what can be used is not limited to these.
The thermal permeation rate and the significance of the numerical limitation will be described later in the section “Supplemental explanation about the contents of the present invention”.

As a fourth invention belonging to the present invention, a holding mold includes a surface layer made of a material having a heat permeability (b value) of 20 or less and a back body made of a material having a heat permeability (b value) larger than that of the surface layer. It is particularly preferable to use a configuration consisting of
In this case, the heat permeability of the surface layer forming material is more preferably 15 or less, and still more preferably 10 or less. Further, the thickness of the surface layer is required to be 0.04 mm or more, preferably 0.06 mm or more, and more preferably 0.1 mm or more. The thickness is preferably 30 mm or less, more preferably 10 mm or less, and even more preferably 5 mm or less. Moreover, it is preferable that this thickness is substantially uniform.

The heat permeability of the back body is preferably 3 or more, more preferably 6 or more, and even more preferably 10 or more. Further, the thermal permeability of the back body is preferably 2 times or more than that of the surface layer, and particularly preferably 10 times or more.
The thickness of the back body is not limited and is not limited to a certain thickness or shape. Further, this layer is not limited to a single material layer, and may be an arbitrary multilayer.

As a fifth invention belonging to the present invention, it is preferable that the holding mold is provided with means for adjusting its own temperature (temperature control).
The temperature control means may be provided at any position in the single-material mold. When the molding die has the configuration of the fourth invention, it is preferable that the temperature adjusting means is provided on the back body. As the temperature control means, any known method such as a liquid heat medium, a gas heat medium, an electric heater, or infrared irradiation can be used. For example, the temperature may be adjusted by ventilating the porous material mold. Further, when it is provided in the back layer, it may be provided anywhere inside or outside, and the front surface layer can be temperature-controlled uniformly and constantly by good heat conduction from the back layer, and is particularly preferably used. can do.

Figure 2 shows an example of the holding type. The holding mold 60 includes a surface layer 61 and a back body 62, 63 is a vacuum exhaust hole, 64 is an exhaust passage, and 65 is a heat medium passage for temperature control. With the structure shown in this figure, a PEEK resin layer having a thickness of 0.1 to 2 mm is formed on the back body of the aluminum material 5052, and a fine thermocouple is exposed on the molding surface through the back layer and the surface layer. The mold is high performance. In addition, temperature control means, such as this heat-medium channel | path, are not provided here, You may make it provide arbitrary heating means for the fixing plate which fixes a shaping | molding die.

As a sixth invention belonging to the present invention, the holding mold has a heat permeability (b value) of 15
It is preferable that a means for controlling or automatically adjusting the surface layer temperature is added to the surface layer itself made of the following material or in close contact with the surface layer. Specific examples of the temperature control and automatic adjustment means include the following methods.
1) A method of providing a heating temperature control close to the entire surface behind the surface layer, 2) a method of heating the surface layer itself, 3) a method of providing a temperature uniformizing layer close to the back of the surface layer, 4) a back of the surface layer The method of providing the heat storage body layer closely_contact | adhered to can be mentioned. When these methods are used, the existence of a back body is not always necessary. When a back body is required for holding or fixing the mold, the material preferably has a heat permeability of 15 or less and preferably has a low thermal insulation rate or is not in close contact with the above means.

FIG. 6 shows a specific example of the holding type using the method 1) above. The mold main body 60 having a heating element on the back is composed of a surface layer 61, a heating element 65, and a rear body 62, 63 is a vacuum exhaust hole, 64 is an exhaust passage, and 69 is a lead wire. More specifically, for example, ceramic or the like may be used as a back body, and a sheet heating element may be laid and pasted thereon, and a surface layer may be formed thereon with a material having the predetermined heat permeability. Instead of sticking the sheet heating element, a nickel resistor metal may be plated on the back body and etched to form the heating element. Preferable surface layer materials include heat-resistant resins such as epoxy resin, fluorine resin, polyimide, and PEEK. Although not shown, a mold manufactured by exposing a fine thermocouple tip to the molding surface through the back body and the surface layer is convenient for management of the molding process. An example of manufacturing this type will be described in Examples.

A specific example of the holding type using the method 2) is shown in FIG. The mold 60 having a heat generating surface layer includes 61 heat generating surface layers, 62 a back body, 63 vacuum exhaust holes, 74 exhaust passages, and 69 lead wires. More specifically, for example, a ceramic or the like is used as a back body, and a planar heating element having the predetermined heat permeability is attached as a surface layer thereon, or can be produced by forming it thereon. .
Examples of commercially available planar heating elements include an impregnated body and a composite resin body containing graft carbon (Nippon Pioneix Corporation). An example of manufacturing this type will be described in Examples.

Specific example of holding type using the above method 3) is shown in FIG. The mold 60 includes a surface layer 61, vacuum exhaust holes of heat storage uniform layers 67 and 63, an exhaust passage of 64, and a back body of 55. For the surface layer 61, the aforementioned material may be used. As the material of 67, a material such as copper (b value 33.9), aluminum (b value 23.3), silicon carbide (b value 16 to 21) may be used. The back body of 62 may be made of a material having a small b value such as engineering plastic or selected ceramics. An example of manufacturing this type will be described in Examples.

<About molding method>
Using the above-described molding apparatus of the present invention, thermoforming involving heat treatment of a resin sheet can be carried out efficiently at high speed. Efficient continuous molding can be performed using a long molding material resin sheet. Although the shaping | molding method using the shaping | molding apparatus of this invention is not limited, the method of the following invention is a particularly preferable method.

As a tenth invention belonging to the present invention, using the molding apparatus of the above invention, using a thermoplastic resin sheet, a preheating step, a shaping step, a heat treatment step for heat treatment at a temperature higher than the preheating temperature of the sheet, and if necessary A molding method for performing the cooling step can be preferably used.

As an eleventh invention belonging to the present invention, as a method of heat-treating a shaped body at a high temperature, 1) a method of ejecting a heated gas from the gas ejection mold, or 2) a method of heating and using the holding mold, the above method is used. Molding can be preferably performed.

In the above molding process, the resin sheet is preheated with a preheating oven or a heating plate, then guided to the female mold and the male mold, and the female mold or the male mold is moved up and down, and both molds are fitted by mixing the resin sheets. Then, it is formed by heating and cooling the shaped body by gas injection, separating both molds and releasing the shaped body.

Methods for heating the shaped body include 1) a method of ejecting heated gas from the injection mold, and 2) a method of heating and using the holding mold, both of which may be used. You can also use one or the other.
Methods for cooling the shaped body include 1) a method of ejecting a relatively low temperature gas from the ejection mold, and 2) a method of using the holding mold while maintaining it at a relatively low temperature. However, it can also be performed using any one of them. Among these cooling methods, at least a method of ejecting a relatively low temperature gas from the above injection mold is preferably used.

As a shaping method, a) a method by completely mating male and female dies, b) a method using both male and female dies incomplete fitting and vacuum, and c) using both male and female dies incomplete fitting and compressed air. Method, d) Any of the respective methods of vacuum shaping (vacuum shaping is preceded and male and female molds are incompletely fitted) can be adopted. However, in the method in which gas is injected from the above injection type and combined with compressed air shaping, the cooling gas can be used as it is, or the heating gas can be used as it is, which is convenient. Can be preferably employed.
In addition, without using an oven or other device for preheating the resin sheet, the unheated resin sheet is guided between the injection mold and the holding mold, and slowly fitted while injecting heated gas from the injection mold. It can be shaped by a predetermined method. In this case, the molding apparatus may not include a preheating device such as an oven.

The condition setting of the above molding method can be explained by dividing it into three patterns. The molding process with heat treatment can draw a continuous molding cycle like a sine curve when looking at changes in the surface temperature (T) of the mold and the internal temperature (S) of the mold. As an example, consider the case of using a mold consisting of a surface layer and a back layer as described above. The back layer temperature is S, the mold surface temperature is T, the maximum temperature is Tt, and the minimum temperature Tb.

Pattern A is a pattern for adjusting S to a constant temperature between Tt and Tb of the surface temperature cycle. In this case, Tt is a temperature reached by high-temperature gas injection, and Tb is a temperature reached by the cooling means. Direct temperature control of the back layer may or may not be performed. If the molding is continued continuously for a long time in a state in which heat does not escape from the back feeding, the back layer temperature S settles between Tt and Tb of the surface temperature cycle. In this case, if the thermal permeability of the back layer is not so large, S is not linear in time in the vicinity of the surface layer, but draws a small temperature cycle following the surface layer. It is desirable to adjust the temperature of the back layer to an appropriate temperature, and the heating means and the cooling means can be set to the optimum shortest time depending on the temperature.

Pattern B is a pattern for adjusting S to a constant temperature equal to or lower than Tb. In this case, Tb is reached mainly by heat transfer at the temperature of S in the back layer. The cooling means is not essential, but if used, the cycle can be shortened. Tt is reached by high temperature gas injection.

Pattern C is a pattern for adjusting S to a constant temperature equal to or higher than Tt. In this case, Tt is reached mainly by the heat transfer from the back layer, that is, the temperature of S. Therefore, the heating temperature control of the back layer is essential. Although heating by high-temperature gas injection is not essential, the cycle can be shortened if used. Note that Tb is reached by cooling gas injection.
In the configuration of the molding apparatus of the present invention, molding with heat treatment can be performed at a high speed corresponding to any of the A, B, and C patterns.

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

(1) <About heat penetration rate>
The thermal permeation rate (b value) used as the specified value of the present invention is a characteristic value of an object related to the amount of heat moving through the interface and the contacting object, and is obtained by the following equation.
b = (λρC) ^1/2 (1)
Where λ: thermal conductivity (Js ⁻¹ m ⁻¹ K ⁻¹ ), ρ; density (kgm ⁻³ ),
C; Specific heat (Jkg ^-1 K ^-1 )

An object with a small b value allows only a small amount of heat to flow through the interface and does not give a large temperature change to the counterpart object, and is subject to a large temperature effect from 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.

[Supplement under rule 26 31.08.2012]
For example, the b value is about 17 to 23 for an aluminum material, about 13 to 16 for an iron material, about 34 copper, 8.0 for a non-rust steel (SUS306), and 0.0 for many synthetic resins. About 2 to 0.8, many ceramics fall between 1 and 20.
Table 1 illustrates the b values of some materials. The b value also shows a slightly different value depending on the measurement temperature, but in the present application, strictly, it is defined by a measurement value of 20 ° C. However, in the case of a composite material with a material having no linearity in a change between 20 ° C. and 200 ° C., for example, a heat storage agent accompanied by a phase change, an average value of 100 ° C. and 150 ° C. should be adopted. To do. It should be noted that even if the same material is used, if the shape changes to a foam or a porous body, this value will change greatly.

(2) <Significance of numerical limitation of mold configuration>
When a surface material having a large thermal permeability b value is used as the surface layer of the mold, heat is easily dispersed from the shaped body to the back, so that heated air or cooling air having a relatively small heat capacity is used. Then, it becomes impossible to heat and cool the shaped body easily, and when this value is more than 25, it is not possible to efficiently perform the heat treatment. This value is preferably small, but if it is smaller than 0.01, there is no material that can withstand use such as strength.

The above mold has a structure of two or more layers, the back layer of the surface layer is controlled to a constant temperature, and the molding surface temperature of the surface layer that changes in temperature by the heating gas and the cooling gas through the shaped body is set to a desired level. Quick return to the reference temperature.
In this case, if the thickness of the surface layer exceeds 30 mm, the control of the back layer takes too much time to reach a steady state in response to the surface temperature, which is not practically effective. Moreover, when this thickness is less than 0.03 mm, the influence of the temperature of a back layer is received greatly, and the effect which accelerates | stimulates temperature rising / falling of a quick shaping body loses. For example, in a known molding method, even if a mold such as a fluorine resin is temporarily formed on the mold for lubrication and release, the coating thickness is as thin as 30 μm or less. There is no need to do this, and it is difficult to apply a thick and smooth coating.

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, a material composed of a single material having a thermal permeability b value (kJ / m ² s ^1/2 K) of 0.01 to 3 preferably has no heating temperature control mechanism, As for those composed of three or more single materials, those equipped with a heating temperature control mechanism can be used more preferably.
In addition, it is desirable that the above-mentioned mold has a fine hole that enables vacuum forming or evacuation at the time of forming, and is housed in the above-mentioned mold storing box so that it can be evacuated.

(3) <Temperature measurement of shaped body>
In the apparatus of the present invention, it is important to measure the change in the surface temperature of the mold or the interface temperature between the mold and the shaped body or the temperature change of the shaped body by some method. Specifically, for example, an extremely delicate measurement probe, for example, a thermocouple tip having a wire diameter of about 0.1 mm is projected on the molding surface of the mold, and this can be measured. As another method, there is a method of measuring the shaped body from the opposite surface without contact with an infrared thermometer. However, there are points to note.

In the patterns A and C, the temperature of the S-line is actively controlled to control the temperature of the mold itself. However, depending on the distance from the molding surface or the distance from the heat source, the molding cycle is repeated with a temperature gradient. It is also a value that stabilizes at.
When strictly considering the heat treatment temperature or mold release temperature of the shaping material, it should be noted that these temperatures are considerably different from the surface temperature or interface temperature shown here. This is because when heating and cooling are performed in units of seconds or less, a large temperature gradient occurs in the thickness direction of the shaped body. Also, temperature measurement from the back of the shaped body with infrared rays or the like does not accurately represent the material temperature. In the present invention, it is expressed by the surface temperature (interface temperature), but there is a difference from this temperature and it is necessary to consider it as a relative value.

Using the mold shown in FIG. 2, the stretched PET sheet was molded with heat treatment.
1) Molding material A 2.3 times uniaxially stretched sheet of homopolyethylene terephthalate resin (though not heat-fixed) having a thickness of 0.23 mm was used.

2) Molding equipment
The molding machine used was a single wafer vacuum / pneumatic molding machine with a pneumatic capacity of 10 tons.
As the forming die , a male and female forming die having a completely fitting shape for forming a circular dish having a depth diameter of 90 mm and a depth of 30 mm was used.
The injection type (male type) has the structure shown in FIG. 2 and is provided with five gas injection holes having a diameter of 1.5 mm centering on the top of the molding surface of the injection port 41 made of aluminum A5052. The molding surface was coated with 30 μm of tetrafluoroethylene resin. It should be noted that when the gas injection mold is lifted slightly after fitting and shaping, the molded product shape design is such that a gap is formed that allows the gas to freely flow away from any part of the shaped body.
The holding mold is of the surface layer / back body type shown by 60 in FIG. 2, and has aluminum A5052 (b value 17.4) as a back layer, and PEEK resin (b value 0.35) 0.14 mm on it. The surface layer was formed by a coating baking method. The outer dimension of the mold was 110 mm square, and the surface layer was indirectly heated through the heating medium in the heating medium passage of the back body.
The temperature measurement was performed by exposing the tip of the thin wire thermocouple to the molding surface so that the molding surface temperature and the shaped body interface temperature could be measured.

3) Molding method and molding conditions First, the resin sheet was preheated and moved for 9 seconds in a preheating oven set at 550 ° C. and placed on the upper part of the mold. The sheet preheating temperature is 95 ° C. The injection mold surface was preheated to 95 ° C, and the holding mold surface was preheated to 185 ° C.
In the shaping process , the holding mold was vacuum-operated simultaneously with shaping by mold fitting for 0.4 seconds. The holding mold molding surface instantaneously decreased to 163 ° C. Next, the gas injection mold was immediately lifted and held as it was, and a heat treatment step by temperature increase by heat transfer from the mold surface was performed for 0.8 seconds. The surface (interface) temperature reached approximately 180 ° C.
The mold floated 6 mm, and a gas injection space (gap) of 3 to 6 mm was formed.
The subsequent cooling process was performed by gas injection for 3.2 seconds. The injected gas used was introduced by introducing compressed air of about 30 ° C. and an original pressure of 0.7 MPa. The injection gas was exhausted from the peripheral part of the flow mold along the gas injection space (gap). After the air injection, the injection mold was further separated to release the mold. The surface temperature at the time of mold release was about 170 ° C. In addition, the vacuum holding of the shaped body was continued until release.

4) Molding result;
The obtained molded product had a good shape. A heat resistance test was conducted by immersing in silicon oil at 130 ° C. for 2 minutes. There was no deformation or conspicuous shrinkage, and it was excellent in heat resistance. It was found that this mechanism can perform powerful jet cooling in combination with the use of a mold having a surface layer with a relatively low thermal permeability, which can be cooled and released in a short time.

Using the mold shown in FIG. 3, the material-stretched PET sheet was changed to perform molding with heat treatment.
1) Molding material A 2.5-fold uniaxially stretched sheet of homopolyethylene terephthalate resin (those not heat-fixed) having a thickness of 0.23 mm was used.

2) Molding apparatus molding machine: the same as in Example 1 was used.
Molding die: The structure shown in FIG. 3 was used as a fully-fitting male-female molding die for molding a round dish having a diameter of 90 mm and a depth of 30 mm.
Injection type (male type); the structure shown in FIG. 3 composed of a gas supply 41 and an exhaust 51 made of aluminum A5052. The molding surface was coated with 30 μm of tetrafluoroethylene resin. It should be noted that when the gas injection mold is lifted slightly after fitting and shaping, the molded product shape design is such that a gap is formed that allows the gas to freely flow away from any part of the shaped body.
Holding type (female type): A structure of FIG. 3 constituted by a single body of S45C (b value 14.0) was used. The outer dimension of the mold was 110 mm square, and the surface layer was indirectly heated through a heating medium on the back body.

3) Molding method and molding conditions The resin sheet was preheated in the same manner as in Example 1 and preheated to 95 ° C. The injection mold surface was preheated to 95 ° C, and the holding mold surface was preheated to 198 ° C.
Forming step : Holding mold was vacuumed simultaneously with mold fitting, and fitting shaping vacuum was performed for 0.4 seconds. The surface temperature instantaneously became about 175 ° C. almost simultaneously with shaping.
Heating and heating step (heat treatment step) : Immediately after shaping, the injection mold was floated and held for 0.3 as it was, and the temperature of the shaped body was increased by heat transfer from the holding mold. The surface temperature remained at about 175 ° C. The mold float was 6 mm, and a gas injection space (gap) of 3 to 6 mm was formed.
Cooling step : Air was injected from the injection mold for 3.7 seconds. The jet air was used after introducing compressed air of about 30 ° C. and an original pressure of 0.7 MPa. Valve operation was performed so that the gas injected into the injection space (gap) was accommodated in the exhaust body through the suction hole and exhausted to the outside. The surface temperature at the time of mold release was about 170 ° C. In addition, the vacuum holding of the shaped body was continued until release.

4) Molding result As in Example 1, a good molded product was obtained. Despite the use of a mold with a relatively high thermal permeability, it was found that mold release was possible in a short time, and that powerful jet cooling was possible with this mechanism.
In this example, the surface temperature did not change greatly during the heat treatment and cooling, but with strong cooling injection, there was a cooling effect with a large temperature gradient in the shape of the shaped body, and good mold release was possible. It is thought that.

Using the mold shown in FIG. 4, the stretched PET sheet was molded with heat treatment.
1) Molding material A 2.5-fold uniaxially stretched sheet of homopolyethylene terephthalate resin (those not heat-fixed) having a thickness of 0.21 mm was used.

2) Molding apparatus The same molding machine as in Example 1 was used.
The molding die was a male and female molding die of incomplete fitting (loose fitting) for molding a round dish shape having a depth of 90 mm and a depth of 30 mm and having a structure shown in FIG.
The injection type is made smaller than the shaped body holding type, and when fitted, a uniform gap space of about 6 mm is formed.
The injection type (male type) has the structure shown in FIG. 4, consisting of an air supply 41 made of aluminum A5052, and an exhaust body 51. The molding surface was coated with 30 μm of tetrafluoroethylene resin. The gas supply 41 injects a high-temperature gas and then takes in and exhausts a low-temperature gas. The exhaust body 51 first takes in and exhausts the high-temperature injection gas, but in the next step, it has a mechanism for injecting the low-temperature gas.
The holding mold is of the surface layer / back body type shown in 60 of FIG. 4 and has aluminum A5052 (b value 17.4) as a back layer and 0.3 mm of PEEK resin (b value 0.35) thereon. The surface layer was formed by a coating baking method. The outer dimension of the mold was 110 mm square, and the surface layer was indirectly heated through the heating medium in the heating medium passage of the back body.

3) Molding method and molding conditions
The resin sheet was preheated in the same manner as in Example 1 to 95 ° C. The injection mold surface was preheated to 95 ° C., and the holding mold surface was preheated to 130 ° C.
Forming step : Performed by simultaneous vacuum operation of fitting and holding mold. The shaping was completed instantly. The surface temperature was about 130 ° C. and there was no significant change.
In addition, since the mold fitting was fitted to the position where the horizontal plane of the gas injection mold floated leaving a gap of 6 mm, the process moved to the next step.
Heating and heating step (heat treatment step): High-temperature air was jetted for 2.8 seconds from an injection-type gas supply. The jet gas was contained in an exhaust body and exhausted. The jet gas temperature was 310 ° C., and the surface temperature was raised to 180 ° C.
Cooling step : Low temperature air was injected from an injection type exhaust body for 1.5 seconds. The jet gas was contained in a gas feed and exhausted. The injected low-temperature air was used after introducing compressed air having an original pressure of about 0.4 MPa at 30 ° C. After gas injection, mold release was performed by further separating the gas injection mold. In addition, the vacuum holding of the shaped body was continued until release. The surface temperature at the time of mold release was 135 ° C.

4) Molded product with good molding results was obtained. The molded product was resistant to silicon oil heat of about 130 ° C., and the heat treatment was effective.

Using the mold shown in FIG. 5, the stretched PET sheet was molded with heat treatment.
1) Molding material : The same material as in Example 2 was used.

2) Molding apparatus The same molding machine as in Example 1 was used.
The molding die was a male and female molding die of incomplete fitting (loose fitting) for molding a circular dish having a diameter of 90 mm and a depth of 30 mm and having a structure shown in FIG. Note that the gas injection type is smaller than the shaped object holding type, and when fitted, a closed space is formed with a uniform gap of about 6 mm.
Injection type (male type) : The structure shown in FIG. 5 comprising an injection port 41 and an exhaust port 51 made of aluminum A5052. The molding surface was coated with 30 μm of tetrafluoroethylene resin. As in the case of the third embodiment, the gas supply 41 injects a high-temperature gas, then takes in a low-temperature gas and exhausts it, and the exhaust body 51 first takes in the high-temperature injection gas and exhausts it. It is a mechanism to inject. This mold is provided with a bank (closing wall) for forming a closed space.
Holding type ; surface layer / back body type 60 shown in FIG. 5, with aluminum A5052 (b value 17.4) as the back body, and PEEK resin (b value 0.35) 0.14 mm above it What formed the surface layer by the coating baking method was used. The outer dimension of the mold was 110 mm square, and the surface layer was indirectly heated through the heating medium in the heating medium passage of the back body.

3) Molding method and molding conditions ;
The resin sheet was preheated to 95 ° C. in the same manner as in Example 1. The injection-type gas supply set temperature was 270 ° C., and the injection-type exhaust body set temperature was 95 ° C. The molding surface of the holding mold was preheated to 160 ° C. to perform molding.
Forming step : After fitting the molds, high-pressure gas injection and vacuum / pneumatic forming using vacuum were activated. The high temperature gas was injected for 0.3 seconds from the gas injection type gas supply, which led to the next step of opening the exhaust valve of the exhaust body. The introduced high temperature gas is the same as the next step. The surface temperature temporarily decreased slightly to 158 ° C.
Heating temperature raising step : Heating air was jetted from a gas jet type gas supply for 2.8 seconds. The valve of the exhaust body was opened, and the jet gas was accommodated in the exhaust body and exhausted. The jet gas temperature was 265 ° C. The surface temperature was raised to 181 ° C.
Cooling step : Low-temperature air injection was performed from an injection-type exhaust body for 0.8 seconds.
The jet gas was contained in a gas feed and exhausted. The injected low-temperature air injection was performed by introducing compressed air having an original pressure of 0.4 MPa at about 30 ° C. After gas injection, the gas injection mold was separated again to perform release. In addition, the vacuum holding of the shaped body was continued until release. The surface temperature at the time of mold release was 135 ° C. The surface temperature at the time of mold release was 158 ° C.

4) Molded product with good molding results was obtained. The molded product withstood at least about 140 ° C. silicone oil, and heat treatment was effective.

Machin (Ishihara Pharmaceutical Co., Ltd., b value 1.7), which is an easy-to-cut ceramic material describing the manufacturing example of the holding mold shown in Fig. 6 , is cut to produce a back body, and a nickel alloy thin film is patterned on it. A PEEK resin film (Victrex, thickness 0.2 mm, b value) pre-heated as a surface layer was spread with a sheet-like heating element sandwiched between PEEK resin thin films and spotted with an adhesive. 0.35) was pressure-air shaped, fixed in vacuum, and baked at 380 ° C. together with the main body. By this baking, adhesion between the respective layers was achieved, and crystallization of the PEEK resin progressed, so that the heat resistance became high.

The molded product was a 75 × 150 mm square and 30 mm deep tray-shaped product, and the outer dimension of the mold was a 84 × 168 mm square and a height of 55 mm.
The thickness of the surface layer was about 0.2 mm. The b-value of the PEEK resin in the surface layer seems to have increased somewhat due to crystallization, but it does not exceed the most preferred range of the present invention.
This type of temperature rise test was conducted, and it was found that the variation was within several degrees when the surface temperature was 180 ° C., which was very preferable.
Although not shown in the drawings, the thermocouple tip was made to be exposed on the molding surface through the back body and the surface layer.

An example of manufacturing the mold shown in FIG. 7 will be described .
A back body (back layer) is made of the same material as in 1) above, and a tape-like graft carbon-impregnated glass cloth (made by Nippon Pioninics, a material that generates heat when energized from both ends) is placed side by side, and then PEEK powder A suspension (manufactured by Okitsumo) was applied, soaked and dried, and the whole was fired at 380 ° C. Although the value of the thermal permeability of the formed surface layer is not accurately measured, it is estimated to be about 0.5 to 2.0 in view of the material used, and does not exceed the most preferable range of the present invention. .
The dimensional shape of the molded product and the mold was the same as 1) above. This type of temperature rise test was conducted, and it was found that when the surface temperature was 180 ° C., the variation was within several ° C., which was very favorable.

A back body is manufactured by cutting a polyimide resin block material (DuPont Vespel, b value 0.36) describing a manufacturing example of the holding mold of FIG. 8 and a molding test using the holding mold, and copper-plated thereon. (Thickness 0.2 mm) was applied to form a temperature uniform layer, and a heat-resistant epoxy resin coating (b value 0.7, thickness 0.25 mm) was further formed thereon to form a surface layer. The coating unevenness was corrected by cutting by machining.
Further, a delicate temperature sensor tip was provided in contact with the temperature uniformizing layer and the molding surface. The dimensional shape of the molded product and the mold was the same as 1) above.

Since this holding mold is not equipped with a heating means, a molding test was performed by combining the injection mold of the present invention capable of injecting heated gas with infrared radiation. First, without heating the molding material, heating gas injection, heating by infrared rays and cooling by room temperature air injection are repeated at intervals of the molding cycle, and the temperature uniformizing layer is heated to a certain steady temperature and accompanied by actual heat treatment. A molding test was conducted. Even when the molding test was repeated continuously, uneven portions such as whitening, cracks, and partial transparency reduction did not occur at the edge of the molded product.
In this molding result, the heat storage homogenization layer not only corrects the temperature non-uniformity of the surface layer, but also stores heat from the heat treatment of the previous molding cycle and supplies it to the surface layer in the next cycle. Indicates that you have been able to continue.

The following is possible for thermoforming according to the present invention.
(1) A molding process involving heat treatment and cooling mold release for heating the shaped body above the preheating temperature for shaping can be carried out at a very high speed, continuously, efficiently and stably.

(2) A specific application requiring such heat treatment is thermoforming that involves heat-fixing of a stretched crystalline resin sheet. Examples of the material include stretched sheets such as PLA, thermoplastic resin such as PET, crystalline resin such as polypropylene, polyamide, and PEEK.

(3) Among them, in particular, by performing thermoforming that performs the above heat treatment using a stretched PET sheet, it is possible to efficiently produce thermoformed products having excellent mechanical strength such as heat resistance, transparency, and rigidity. Can do. Further, it is possible to obtain a material-saving molded product using rigidity, and to meet the social needs of resource saving.

(4) A crystalline resin sheet that has not been subjected to stretching treatment, for example, can be used for molding involving crystallization of PET (CPET) to which a crystal nucleating agent is added, and this can be performed at a higher speed than before. it can.

(5) In addition, expecting a new method, etc. that can be applied to SPPF molding of polypropylene (solid phase high pressure molding) to solve the disadvantages of this molding method (reducing residual stress distortion and improving heat-resistant dimensional stability). Can do.

(6) Molding with heat treatment can be performed precisely, uniformly, without variation, at high speed and with energy saving, and the improvement in strength and rigidity due to orientation and crystallization has been converted to a material with reduced thickness, It is possible to contribute to the social needs for resource conservation.

11 Press machine top plate 12 Press machine bottom plate 13 Insulation material 40 Injection mold (part of male and female mold)
41 Injection port (takes the function of the exhaust port from the middle of the process depending on the molding mode)
42 Air supply passage (changes to exhaust passage from the middle of the process depending on the molding mode)
43 branch passage (changes to the air collection passage from the middle of the process depending on the molding mode)
43b Relay space 44 Molding surface 45 Injection hole (changes from the middle of the process to the intake hole depending on the molding mode)
46 Gas introduction passage 47 Heater 48 Air supply board 49 Operation valve 50 Injection space (gap)
51 Exhaust port (responsible for the function of the air supply port from the middle of the process depending on the molding mode)
52 Exhaust passage (changes to the air supply passage from the middle of the process depending on the molding mode)
53 Air collection passage (changes to a branch passage from the middle of the process depending on the molding mode)
53b Relay space 54 Heater 55 Intake hole (changes to gas injection hole from the middle of the process depending on the molding mode)
56 Exhaust passage 57 Heater 58 Heat insulation material 59 Operation valve 51b Bank (closing wall)
60 Holding mold (part of male and female mold)
61 Surface layer
62 Back layer (back body)
63 Vacuum exhaust hole
64 Vacuum exhaust passage 65 Temperature control means (heat medium passage or heater)
66 Stacking plate
67 Soaking means or heat storage means
68 Self-heating surface layer
69 Lead wire
110 Shaped body of thermoplastic resin sheet A Compressed gas
A 'Exhaust HA High-temperature compressed gas HA' High-temperature exhaust

Claims (11)

1. In a resin sheet thermoforming apparatus, a gas injection hole is provided on the molding surface of either a female mold or a male mold to inject at least one of a cooling gas and a heating gas, and the injection gas is applied to the entire surface of the shaped body. A male / male mold comprising a mold having a space forming function for diffusion (hereinafter referred to as an injection mold) and another mold corresponding thereto (hereinafter referred to as a holding mold), and means for introducing compressed gas into the injection mold A thermoplastic resin configured to heat or cool the shaped body held by the holding mold by injecting the introduced gas from the injection mold surface at a distance away from the shaped body after shaping the resin sheet Resin sheet molding equipment.
2. The molding apparatus according to claim 1, further comprising means for holding the shaped body in close contact with the molding surface of the holding mold.
3. The holding mold is characterized in that at least the molding surface is made of a material having a thermal permeability (b value) (kJ / m ² s ^1/2 K) of 0.01 to 25. The molding apparatus according to claim 1 or 2.
4. The holding mold includes a surface layer made of a material having a heat permeability (b value) of 20 or less and a back body made of a material having a heat permeability (b value) larger than that of the surface layer. The molding apparatus according to any one of 1 to 3.
5. The molding apparatus according to any one of claims 1 to 4, wherein the holding mold includes means for controlling its own temperature.
6. The holding mold is provided with a means for controlling or automatically adjusting the surface layer temperature by being in close contact with or behind the surface layer made of a material having a thermal permeability (b value) of 15 or less. The molding apparatus according to claim 1, wherein the molding apparatus is provided.
7. In the injection type, in addition to a mechanism for injecting gas from the gas injection hole, a mechanism for inhaling and exhausting the injected gas from an intake hole provided separately from the injection hole is provided. The molding apparatus according to any one of claims 1 to 6.
8. In the above injection mold, injection can be performed by changing the type of gas in the middle of one molding process. The molding apparatus according to any one of claims 1 to 7, wherein the molding apparatus is configured to function as a mechanism for injecting from the inside.
9. The male and female molds are configured to form a compressed air space that is closed when they are joined with a resin sheet interposed therebetween, and to perform compressed air shaping by injecting gas from the above injection mold. The molding apparatus according to any one of claims 1 to 8, wherein
10. A resin sheet molding method using the molding apparatus according to claim 1, wherein the resin sheet is preheated, shaped, heat treated at a temperature higher than the sheet preheat temperature, and necessary A method for forming a thermoplastic resin sheet, wherein the cooling step is performed.
11. The method for heat-treating a shaped body at a high temperature uses at least one of 1) a method of injecting heated gas from the injection mold, or 2) a method of heating and using the holding mold. Molding method

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