JP2023168858A - Thermoforming device - Google Patents

Abstract

To provide a thermoforming device which can improve trimming accuracy and reduce environmental loads.SOLUTION: A thermoforming device 1 includes a radiation heating device 6, and a base 52 opposite to the radiation heating device 6 across a resin film 4, and performs a heating step of radiation heating the resin film 4 to a predetermined moldable temperature C21 by the radiation heating device 6, and a bonding step of bonding the resin film 4 subjected to the radiation heating to a pulp mold 10 mounted on the base 52, wherein the resin film 4 is cut into a shape along the contour of a flange part 103 of a bonded surface 104 to which the resin film 4 is bonded of the pulp mold 10, in a state of being bonded to the flange part 103, before the heating step and the bonding step.SELECTED DRAWING: Figure 1

Description

The present invention includes a radiant heating device, a base that faces the radiant heating device with a resin film in between, and a heating step for radiantly heating the resin film to a predetermined temperature at which the resin film can be molded by the radiant heating device; The present invention relates to a thermoforming apparatus for performing an adhesion process of adhering a radiation-heated resin film to a fiber molded article placed on a base.

Plastic containers have conventionally been used as food packaging containers, but plastic containers do not decompose naturally when discarded, and are therefore considered to be a cause of environmental pollution. Under these circumstances, fiber molded products such as pulp molds, which naturally decompose even when discarded, are expected to reduce environmental pollution and are increasingly being used as food packaging containers. .

When a fibrous molded body is used as a food packaging container, if the food is filled as is, water and oil contained in the food may penetrate into the fibrous molded body, causing leakage. For this reason, it is common to adhere a thermoplastic resin film to the surface of the fibrous molded product that will come into contact with food, thereby imparting water resistance and oil resistance to the fibrous molded product. For example, Patent Document 1 discloses a paper container to which a resin film is adhered.

The adhesion of the resin film to the fiber molded article is carried out using, for example, a radiant heating device 6 for heating the resin film 4 and a pulp mold 10 (an example of the fiber molded article) as shown in FIG. This is carried out using a thermoforming apparatus 100 that includes a lower mold 5.

The thermoforming device 100 uses a radiation heating device 6 to radiantly heat the resin film 4 to a predetermined temperature at which it can be molded, and adheres the radiantly heated and softened resin film 4 to a pulp mold 10 placed on a lower mold 5. It is a device for Note that the process of radiant heating the resin film 4 by the radiant heating device 6 to a predetermined temperature at which it can be molded is called a heating process, and the resin film 4 softened by radiation heating is placed in the pulp mold 10 placed on the lower mold 5. The process of bonding is called the bonding process.

The shape of the pulp mold 10 is, for example, an elliptical bottom 101 in a plan view (viewed from above in FIG. 6), a peripheral wall 102 rising from the periphery of the bottom 101, and a pulp mold extending from the upper end of the peripheral wall 102. 10 and a flange portion 103 projecting outward. Further, the inner surface of the pulp mold 10 on the radiant heating device 6 side (upper side in FIG. 6) is an adhesive surface 104 to which the resin film 4 is adhered.

The resin film 4 is, for example, a thermoplastic film made of polypropylene (PP). The thickness is, for example, 80 μm. The melting point of the resin film 4 is, for example, 167° C., and in the heating step, it is heated to 160° C. (temperature C21 (see FIG. 7(d))), which is a predetermined temperature at which it can be molded. An adhesive layer (not shown) made of a heat sealant or the like is provided on the surface of the resin film 4 facing the pulp mold 10 in order to improve adhesiveness with the pulp mold 10.

The lower mold 5 includes a mold 51, a pedestal 53, and a base 52. The formwork 51 includes a pedestal 512 and a peripheral wall 511 erected on the pedestal 512. The pedestal 512 has a vent 512a penetrating in the vertical direction VT, and the vacuum pump 7 is connected to the vent 512a. The vacuum pump 7 can vacuum the inside of the formwork 51 through the vent 512a.

A pedestal 53 on which the base 52 is mounted is fixed above the pedestal 512 and surrounded by a peripheral wall 511 . The pedestal 53 has a plurality of communication passages 531 passing through the pedestal 53 in the vertical direction VT. A base 52 on which the pulp mold 10 is placed is mounted on the upper end surface of the base 53 in the vertical direction VT, surrounded by a peripheral wall 511.

The base 52 has a mounting surface 521 that matches the shape of the pulp mold 10 on the end surface on the radiant heating device 6 side (upper side in the vertical direction VT). Further, the base 52 includes a plurality of vacuum vents 522 that open to the mounting surface 521. When the inside of the mold 51 is vacuum-suctioned by the vacuum pump 7, the mounting surface 521 side can be vacuum-suctioned through the communication path 531 and the vacuum vent 522. By applying vacuum suction to the mounting surface 521 side in the state shown in FIG. 6, it becomes possible to adhere the resin film 4 to the adhesive surface 104 of the pulp mold 10 without any gaps. Since the pulp mold 10 has air permeability, even if the pulp mold 10 is placed on the placement surface 521, pressurization and vacuum suction on the placement surface 521 side will not be hindered.

The radiant heating device 6 is located opposite the lower mold 5 with the resin film 4 interposed therebetween. The position of the radiation heating device 6 shown in FIG. 1 is a heating position for performing radiation heating of the resin film 4 in the heating process. The distance D11 of the radiant heating device 6 with respect to the base 52 at the heating position is determined based on the output of the radiant heating device 6, the material of the resin film 4, the target time for the heating process and the bonding process, and the like.

A heating process and a bonding process performed using the thermoforming apparatus 100 having the above configuration will be described using FIG. 7. FIG. 7(a) is a time chart of the output of the radiation heating device 6 in the bonding process and the heating process. FIG. 7(b) is a time chart regarding the pumping speed of the vacuum pump 7 in the bonding process and the heating process. FIG. 7C is a time chart regarding the position of the radiant heating device 6 (distance of the radiant heating device 6 with respect to the base 52) in the bonding process and the heating process. FIG. 7(d) is a graph showing the temperature change of the resin film 4 during the adhesion process and the heating process.

As shown in FIG. 7(a), the output of the radiation heating device 6 is started from time t1, and the heating process is started. The output of the radiation heating device 6 is constant at the temperature C11 throughout the heating process and the bonding process. Note that the value of the temperature C11 is arbitrarily set depending on the performance of the radiant heating device 6, the material of the resin film 4 to be heated, etc., but here, the temperature of the radiant heating device 6 is set to 600°C. . Further, the distance between the radiant heating device 6 and the base 52 is constant at a distance D11 throughout the heating process and the bonding process, as shown in FIG. 7(c).

As shown in FIG. 7(d), the temperature of the resin film 4 increases in proportion to the passage of time from time t1 when heating by the radiation heating device 6 starts. Then, the temperature of the resin film 4 reaches a moldable temperature C21 (160° C.) at time t2, and the heating process is completed. The time required for the heating process (time from time t1 to time t2) depends on the output of the radiant heating device 6, the distance of the radiant heating device 6 from the base 52, the thickness and material of the resin film 4, etc. It takes about 8 seconds.

After the heating process is completed, the thermoforming apparatus 100 performs a bonding process. Specifically, as shown in FIG. 7B, vacuum suction by the vacuum pump 7 is performed at a maximum pumping speed S11 according to the capacity of the vacuum pump 7 from time t2. By performing this vacuum suction, the resin film 4 is shaped along the shape of the pulp mold 10 and is adhered to the pulp mold 10. The time required for the bonding process (time from time t2 to time t6) depends on the output of the radiant heating device 6, the distance of the radiant heating device 6 to the base 52, the material of the resin film 4, etc. Seconds.

Then, the pulp mold 10 with the resin film 4 adhered thereto is carried out from the thermoforming apparatus 100 by sending out the resin film 4 along the horizontal direction HZ (for example, from the left side to the right side in the figure). Then, the thermoforming apparatus 100 adheres the resin film 4 to the next pulp mold 10. In order to continuously bond the resin film 4 to the pulp molds 4 in this way, a plurality of pulp molds 10 are lined up one after the other in the horizontal direction HZ and hang from the resin film 4 that is sent out along the horizontal direction HZ. The state will be as follows. The pulp molds 10 are transported to the trimming process while hanging from the resin film 4, and in the trimming process, the pulp molds 10 lined up one after the other in the horizontal direction HZ are sequentially separated from the resin film 4.

Japanese Patent Application Publication No. 2001-233317

When the resin film 4 is shaped along the shape of the pulp mold 10 in the adhesion process after the heating process, as shown in FIG. An unshaped portion 42 is formed around the portion 41 . This unshaped portion 42 is a portion of the resin film 4 that remains without being shaped. However, due to the heating by the radiation heating device 6 in the heating process and the bonding process, and the unmolded portion 42 being carried out from the thermoforming device 100, there is a possibility that minute deformation or change in physical properties may occur in the unformed portion 42. In this case, the pitch between the pulp molds 10 arranged one after the other in the horizontal direction HZ may shift, which may adversely affect the accuracy of trimming performed after the resin film 4 is bonded.

Furthermore, when trimming, it is difficult to cut only the resin film 4 with high precision, so the tip of the flange portion 103 is cut as shown by a cutting line 15 that hypothetically indicates the position to be trimmed. By doing so, the pulp mold 10 is separated from the resin film 4. After the pulp mold 10 is cut off, the resin film 4 is wound up and discarded, but since the tip of the cut flange portion 103 remains glued, it is difficult to separate it. If it is difficult to separate, it will be difficult to reuse it as a material, and the environmental burden will be large when it is disposed of.

The present invention has been made in view of the current situation, and an object of the present invention is to provide a thermoforming device that can improve trimming accuracy and reduce environmental load.

In order to solve the above problems, the thermoforming apparatus of the present invention has the following configuration.

(1) A heating step comprising a radiant heating device and a base facing the radiant heating device with a resin film in between, and radiant heating the resin film to a predetermined temperature at which the resin film can be molded by the radiant heating device. and an adhesion step of adhering the radiation-heated resin film to the fiber molded article placed on the base, in which the resin film undergoes the heating step and the adhesion step. Before this process, the fiber molded article is cut into a shape along the outer shape of the outer periphery while being adhered to the outer periphery of the adhesive surface to which the resin film is attached.

According to the thermoforming apparatus described in (1), the resin film is bonded to the outer periphery of the bonding surface of the fiber molded article to which the resin film is bonded before the heating step and bonding step are performed. Since the resin film is characterized by being cut into a shape that follows the outer shape of the periphery, the resin film is cut before being heated by the radiant heating device. In other words, the resin film can be cut in a state where the resin film does not undergo minute deformation or change in physical properties due to heating by the radiant heating device. Therefore, trimming accuracy can be improved.

In addition, if we can improve the trimming accuracy, it will be possible to cut only the resin film with high precision when trimming, and after the fiber molded object is separated, a part of the fiber molded object will be attached to the resin film. will not remain. Therefore, it is easy to recycle the resin film as a material after separating the fiber molded body, and even if recycling as a material is abandoned, it is possible to reduce the environmental burden when disposing of the resin film.

(2) In the thermoforming apparatus according to (1), a pressure reduction means for vacuum suction between the fiber molded body and the resin film, and an exhaust speed for performing the vacuum suction of the pressure reduction means are adjusted. and an exhaust speed adjustment section.

(3) In the thermoforming apparatus according to (2), the evacuation speed adjusting section is configured to set a first evacuation speed for performing the vacuum suction in the heating step and a first evacuation speed for performing the vacuum suction in the bonding step. 2, the second exhaust speed is an exhaust speed for bringing the resin film into close contact with the fiber molded body, and the first exhaust speed is the second exhaust speed. It is characterized in that the pumping speed is slower than the pumping speed.

(4) In the thermoforming apparatus according to (3), the output of the radiation heating device is controlled to a heating temperature necessary for the resin film to reach the predetermined temperature within a predetermined time, and the pressure reduction The means performs the heating step by performing the vacuum suction at the first evacuation speed, and after the completion of the heating step, the decompression means performs the vacuum suction at the second evacuation speed, thereby performing the bonding step. The present invention is characterized by comprising a control program that performs the following.

Since the resin film is adhered to the outer periphery of the adhesive surface of the fiber molded body to which the resin film is to be bonded before the heating process and the bonding process are performed, there is no air between the fiber molded body and the resin film. Trapped. Therefore, if the heating step is performed as is, the air trapped between the fiber molded body and the resin film will expand due to the heating by the radiant heating device, and the resin film will swell toward the radiant heating device. Then, the distance between the radiation heating device and the resin film becomes narrower, and the resin film is heated excessively, which may cause defects such as holes.

According to the thermoforming apparatus described in (2), (3), or (4), a decompression means for applying vacuum suction between the fiber molded body and the resin film to bring the resin film into close contact with the fiber molded body; and an evacuation speed adjustment section that adjusts the evacuation speed for performing vacuum suction of the decompression means, so that, for example, in the heating process, the vacuum suction is performed at a first evacuation speed that is slower than the second evacuation speed in the bonding process. By doing this, it is possible to prevent the resin film from swelling toward the radiation heating device. This can prevent the resin film from being excessively heated. The first pumping speed depends on the output of the radiant heating device, the volume of the fiber molded body, etc., but the speed at which the resin film does not swell toward the radiant heating device is determined in advance through experiments. It is something that can be done.

According to the thermoforming apparatus of the present invention, it is possible to improve trimming accuracy and reduce environmental load.

1 is a diagram illustrating the configuration of a thermoforming device according to the present embodiment and illustrating a state in which the thermoforming device is in a heating process. FIG. FIG. 2 is a diagram illustrating a state in which the thermoforming apparatus according to the present embodiment is in a bonding process. FIG. 2 is an enlarged view of a flange portion (an example of an outer peripheral edge) of a pulp mold (an example of a fiber molded object). FIG. 3 is a plan view of the radiant heating device as seen from the heat radiation section side. (a) is a time chart regarding the output of the radiation heating device in the bonding process and the heating process. (b) is a time chart regarding the pumping speed of the vacuum pump in the bonding process and the heating process. (c) is a time chart regarding the position of the radiation heating device in the bonding process and the heating process. (d) is a graph showing the temperature change of the resin film in the adhesion process and the heating process. FIG. 1 is a diagram showing the configuration of a thermoforming apparatus according to the prior art. (a) is a time chart regarding the output of the radiation heating device in the bonding process and the heating process according to the prior art. (b) is a time chart regarding the pumping speed of the vacuum pump in the bonding process and the heating process according to the prior art. (c) is a time chart regarding the position of the radiation heating device in the bonding process and the heating process according to the prior art. (d) is a graph showing the temperature change of the resin film in the bonding process and heating process according to the prior art. FIG. 2 is an enlarged view of a flange portion 103 of a pulp mold 10 to which a resin film is bonded using a conventional thermoforming device.

A thermoforming apparatus according to a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing the configuration of a thermoforming device 1 according to the present embodiment, and also showing a state in which the thermoforming device 1 is in a heating process. FIG. 2 is a diagram showing a state in which the thermoforming apparatus 1 according to the present embodiment is in a bonding process. FIG. 3 is an enlarged view of the flange portion 103 (an example of the outer periphery) of the pulp mold 10 (an example of a fiber molded object). Note that the resin film 4 in FIG. 3 is before trimming along the outer shape of the flange portion 103 is performed. Further, a cutting line 14 in FIG. 3 is a line that virtually indicates a position where trimming is to be performed. FIG. 4 is a plan view of the radiation heating device 6 viewed from the heat radiation section 6a side.

<About the configuration of the thermoforming device>
As shown in FIG. 1, the thermoforming apparatus 1 according to the first embodiment includes a lower mold 5 and a radiation heating device 6, and the radiation heating device 6 reaches a predetermined temperature at which the resin film 4 can be molded. This is a device for radiant heating and bonding a resin film 4 softened by the radiant heat to a pulp mold 10 placed on a lower mold 5. Note that the process of radiant heating the resin film 4 by the radiant heating device 6 to a predetermined temperature at which it can be molded is called a heating process, and the resin film 4 softened by radiation heating is placed in the pulp mold 10 placed on the lower mold 5. The process of bonding is called the bonding process.

The pulp mold 10 is, for example, a food packaging container molded from pulp material to a thickness of about 0.5 to 3 mm. The shape of the pulp mold 10 is not particularly limited, but includes, for example, a bottom portion 101 that is oval in plan view (viewed from above in FIG. 1), a peripheral wall portion 102 rising from the periphery of the bottom portion 101, and a peripheral wall portion 102. The pulp mold 10 has a flange portion 103 extending outward from the upper end of the pulp mold 10. Further, the inner surfaces of the bottom portion 101 and the peripheral wall portion 102 of the pulp mold 10 on the radiant heating device 6 side (upper side in FIG. 1) are adhesive surfaces 104 to which the resin film 4 is adhered. Note that as the pulp material, wood pulp (limited to virgin materials) and non-wood pulp (limited to virgin materials) using reeds, sugar cane, bamboo, etc. are used. However, if the pulp mold 10 is not used for food, in addition to the above, recycled wood pulp and non-wood pulp, and waste paper pulp made from waste paper such as newspapers, magazines, or cardboard may also be used as the pulp material. good. Since the pulp mold 10 is an aggregate of fibers made of pulp material as described above, it has air permeability, and before the resin film 4 is bonded, the upper surface side and the lower surface side in FIG. Air can pass between them.

The resin film 4 is a thermoplastic film made of polypropylene (PP). However, the material is not limited to polypropylene (PP), and may be any material that meets food hygiene standards (for example, standards set by the Food Sanitation Act). For example, olefin resins such as polyethylene (PE), polyester resins such as polyethylene terephthalate (PET), ethylene vinyl acetate copolymers, etc. can be used.

The surface of the resin film 4 facing the pulp mold 10 is the surface that is adhered to the adhesive surface 104 of the pulp mold 10, and an adhesive layer (not shown) is provided to improve the adhesiveness with the pulp mold 10. ing. This adhesive layer is provided by applying a heat-adhesive resin such as a heat-sealing agent, or by extrusion coating a heat-adhesive resin.

The thickness of the resin film 4 is desirably less than 100 μm for the purpose of reducing manufacturing costs, and in this embodiment, for example, a thickness of 80 μm is used. In addition, although the thickness of the resin film 4 is shown to be about half the thickness of the pulp mold 10 in the drawing, this is to make the drawing easier to read, and is different from the actual thickness. Further, the melting point of the resin film 4 is not particularly limited, but is, for example, 167° C., and in the heating step, it is heated to a predetermined moldable temperature. The moldable temperature is, for example, 160° C. (temperature C21 (see FIG. 5(d))) in this embodiment.

Further, before being shaped by the thermoforming device 1, the resin film 4 is cut in advance along the outer shape of the pulp mold 10 in a plan view (viewed from above in FIG. 1). Specifically, as shown in FIG. 1, it is adhered only to the flange portion 103 of the pulp mold 10 and is cut in advance along the outer periphery of the flange portion 103. In other words, the resin film 4 is cut before being heated by the radiant heating device 6, and the resin film 4 is cut without any slight deformation or change in physical properties due to heating by the radiant heating device 6. Film 4 can be cut. Therefore, trimming accuracy can be improved.

Moreover, if the trimming precision can be improved, only the resin film 4 can be cut with high precision when trimming. Specifically, in the past, it was difficult to cut only the resin film 4 with high precision, so trimming was performed at the tip of the flange portion 103, as shown by the cutting line 15 in FIG. However, since the thermoforming apparatus 1 according to the present embodiment can improve trimming accuracy, as shown by the cutting line 14 in FIG. It becomes possible to cut only the resin film 4 with high accuracy, aiming at the boundary with the surrounding resin film 4 that is not bonded. Therefore, no part of the pulp mold remains on the resin film after the fiber molded body (pulp mold 10) is separated. Therefore, it is easy to recycle the resin film as a material after cutting off the fiber molded body (pulp mold 10), and even if recycling as a material is abandoned, the environmental burden at the time of disposal is reduced. be able to.

Note that adhesion and cutting of only the flange portion 103 of the resin film 4 may be performed as a preliminary step by a device different from the thermoforming device 1, or the thermoforming device 1 may be equipped with a cutting device such as a Thomson blade. Alternatively, the thermoforming device 1 may adhere the resin film 4 only to the flange portion 103, and the cutting device may cut the resin film 4 along the outer periphery of the flange portion 103.

The resin film 4 as described above is heated to about 160° C. by the radiation heating device 6 in the thermoforming device 1, and then shaped along the adhesive surface 104 of the pulp mold 10, as shown in FIG. At the same time, it is adhered to the adhesive surface 104. The pulp mold 10 has water resistance, oil resistance, and heat resistance because the resin film 4 is adhered thereto.

The lower mold 5 includes a mold 51, a pedestal 53, and a base 52. The formwork 51 is made of a metal member such as stainless steel, and includes a pedestal 512 and a peripheral wall 511 erected on the pedestal 512. The pedestal 512 has a vent 512a penetrating in the vertical direction VT, and a vacuum pump 7 (an example of a pressure reducing means) is connected to the vent 512a. The vacuum pump 7 can vacuum the inside of the formwork 51 through the vent 512a.

A pedestal 53 on which the base 52 is mounted is fixed above the pedestal 512 and surrounded by a peripheral wall 511 . The pedestal 53 has a plurality of communication passages 531 passing through the pedestal 53 in the vertical direction VT. A base 52 on which the pulp mold 10 is placed is mounted on the upper end surface of the base 53 in the vertical direction VT, surrounded by a peripheral wall 511.

The base 52 has a mounting surface 521 that matches the shape of the pulp mold 10 on the end surface on the radiant heating device 6 side (upper side in the vertical direction VT). Further, the base 52 includes a plurality of vacuum vents 522 that open to the mounting surface 521. When the inside of the mold 51 is vacuum-suctioned by the vacuum pump 7, the mounting surface 521 side can be vacuum-suctioned through the communication path 531 and the vacuum vent 522. Since the pulp mold 10 has air permeability, even if the pulp mold 10 is placed on the placement surface 521, pressurization and vacuum suction on the placement surface 521 side will not be hindered. Therefore, by vacuum suctioning the mounting surface 521 side in the state shown in FIG. This makes it possible to bond without any problems.

The vacuum pump 7 is connected to the vent 512a of the lower mold 5 through a first pipe 11A and a second pipe 11B that are arranged in parallel.

A first on-off valve 8 is arranged on the first pipe 11A. When the first on-off valve 8 is opened, the first pipe 11A is opened, and the vacuum pump 7 can perform vacuum suction through the first pipe 11A. On the other hand, if the first on-off valve 8 is closed, the first pipe 11A is shut off.

On the second pipe 11B, a second on-off valve 9 and a flow rate adjustment valve 13 are arranged in order from the vacuum pump 7 side. When the second on-off valve 9 is opened, the second pipe 11B is opened, and the vacuum pump 7 can perform vacuum suction through the second pipe 11B. On the other hand, if the second on-off valve 9 is closed, the second pipe 11B is shut off. Further, the flow rate adjustment valve 13 has an adjustable valve opening degree, and by adjusting the valve opening degree, it is possible to adjust the exhaust speed when vacuum suction is performed by the second pipe 11B.

The vacuum pump 7 is always in operation while the thermoforming apparatus 1 is in operation, and when the first on-off valve 8 is opened and the second on-off valve 9 is closed, the vacuum pump 7 is turned off by the first piping 11A. Vacuum suction can be performed at the maximum pumping speed S11 (see FIG. 5(b) (an example of the second pumping speed)) according to the capacity. On the other hand, if the first on-off valve 8 is closed and the second on-off valve 9 is opened, the second piping 11B will control the exhaust speed according to the opening degree of the flow rate adjustment valve 13 (for example, at a predetermined rate described below). Vacuum suction can be performed at the pumping speed S12 (see FIG. 5(b) (an example of the first pumping speed)). In other words, the first piping 11A, the second piping 11B, the first on-off valve 8, the second on-off valve 9, and the flow rate adjustment valve 13 function as an evacuation speed adjustment section that adjusts the evacuation speed of the vacuum pump 7.

The radiant heating device 6 is located opposite the lower mold 5 with the resin film 4 interposed therebetween. The end surface of the radiation heating device 6 on the side of the lower mold 5 is a heat radiation part 6a, and the heat radiation part 6a is formed of a plurality of heater elements 61, as shown in FIG. Specifically, the radiant heating device 6 has a configuration in which six rows of heater elements 61 (octagonal in plan view) are arranged adjacent to each other in the X direction, and five rows of heater elements 61 are arranged adjacent to each other in the Y direction. There are a total of 30 heater elements 61. These 30 heater elements 61 constitute a heat radiation section 6a. Note that the X direction in FIG. 4 is a direction parallel to the horizontal direction HZ in FIGS. 1 and 2. Further, the number of heater elements 61 is not limited to the above, but is merely an example.

Further, the radiant heating device 6 is provided with a temperature sensor 62 surrounded by four heater elements 61 located in the central region of the radiant heating device 6, as shown in FIG. The temperature sensor 62 is, for example, a radiation thermometer. This temperature sensor 62 can measure the temperature of the surface of the resin film 4 facing the radiation heating device 6 . Thereby, the thermoforming apparatus 1 can detect the temperature of the resin film 4 during the heating process and the bonding process.

The radiant heating device 6 is movable up and down along the vertical direction VT by a lifting means 12 (for example, an air cylinder, etc.), and is movable between a first heating position and a second heating position. . The position of the radiant heating device 6 shown in FIG. 1 is a first heating position for radiant heating of the resin film 4 in the heating process. The position of the radiant heating device 6 shown in FIG. 2 is a second heating position for radiant heating the resin film 4 in the bonding process. The distance D12 between the radiant heating device 6 and the base 52 at the second heating position is set smaller than the distance D11 between the radiant heating device 6 and the base 52 at the first distance heating position. In this way, since the radiant heating device 6 is movable between the first heating position and the second heating position, the distance of the radiant heating device 6 with respect to the resin film 4 is variable. Note that the distance D11 of the radiant heating device 6 to the base 52 at the first heating position and the distance D12 of the radiant heating device 6 to the base 52 at the second heating position are determined by the output of the radiant heating device 6 and the distance of the resin film 4. It is determined based on the material, target time for heating process and bonding process, etc.

<About the heating process and adhesion process>
The heating process and adhesion process performed using the thermoforming apparatus 1 having the above configuration will be explained using FIG. 5. FIG. 5A is a time chart of the output of the radiation heating device 6 in the bonding process and the heating process. FIG. 5(b) is a time chart regarding the pumping speed of the vacuum pump 7 in the bonding process and the heating process. FIG. 5C is a time chart regarding the position of the radiant heating device 6 (distance of the radiant heating device 6 with respect to the base 52) in the bonding process and the heating process. FIG. 5(d) is a graph showing the temperature change of the resin film 4 during the adhesion process and the heating process.

Before starting the heating step and the bonding step, the resin film 4 is bonded only to the flange portion 103 of the pulp mold 10, and the resin film 4 is attached along the outer shape of the pulp mold 10 in a plan view. Cut. Then, as shown in FIG. 1, the pulp mold 10 is placed on the placement surface 521 of the base 52. Note that the work of placing the pulp mold 10 on the placing surface 521 may be performed manually by an operator, or may be performed by an automatic conveyance device or the like.

Moreover, before starting the heating process and the bonding process, the vacuum pump 7 is operated with the first on-off valve 8 and the second on-off valve 9 closed and the first piping 11A and the second piping 11B cut off. put. Further, the opening degree of the flow rate regulating valve 13 is adjusted so that a predetermined exhaust speed S12 (see FIG. 5(b)) is obtained when the second on-off valve 9 is opened. Note that details of the predetermined pumping speed S12 will be described later.

First, the heating process will be explained. As shown in FIG. 5(a), the output of the radiation heating device 6 is started from time t1, and the heating process is started. The output of the radiation heating device 6 is constant at the temperature C11 throughout the heating process and the bonding process. Note that the value of the temperature C11 is arbitrarily set depending on the performance of the radiant heating device 6, the material of the resin film 4 to be heated, etc., and is not particularly limited; however, in this embodiment, the value of the radiant heating device The temperature is set at 600°C, which is the maximum output of 6. Further, the distance between the radiant heating device 6 and the base 52 is a distance D11, as shown in FIG. 5(c). This means that the radiant heating device 6 is in the first heating position.

As shown in FIG. 5(b), vacuum suction by the vacuum pump 7 starts from time t1 at a predetermined pumping speed S12. This vacuum suction is performed by opening the second on-off valve 9 and opening the second pipe 11B while the first on-off valve 8 remains closed.

Since the resin film 4 is adhered to the flange portion 103 of the pulp mold 10, air is trapped between the pulp mold 10 and the resin film 4. Therefore, if heating is performed directly using the radiant heating device 6, the air trapped between the pulp mold 10 and the resin film 4 will expand, causing the resin film 4 to swell toward the radiant heating device 6 (upper side in FIG. 1). Put it away. Then, the distance between the radiant heating device 6 and the resin film 4 becomes narrower, and the resin film 4 is heated excessively, which may cause defects such as holes. Therefore, as described above, by performing vacuum suction at a predetermined pumping speed S12, the resin film 4 is prevented from swelling toward the radiation heating device 6 side, and the resin film 4 is prevented from being excessively heated. ing.

The predetermined pumping speed S12 depends on the output of the radiant heating device 6, the volume of the pulp mold 10, etc., but the speed at which the resin film 4 does not swell toward the radiant heating device 6 is determined in advance through experiments. I'll ask for it. Then, the opening degree of the flow rate regulating valve 13 is adjusted in accordance with the predetermined exhaust speed S12 determined through experiments. Note that it is desirable that the resin film 4 be kept as horizontal as possible by performing vacuum suction at a predetermined pumping speed S12. This is to uniformly heat the entire resin film 4. However, it is not necessarily necessary to keep it horizontal, and it is sufficient as long as the resin film 4 does not swell toward the radiation heating device 6 side. For example, by performing vacuum suction at a predetermined pumping speed S12, the resin film 4 may be deformed into a concave shape toward the pulp mold 10 to such an extent that shaping is not performed. Further, although vacuum suction at a predetermined pumping speed S12 is performed from time t1 at the same time as the heating process is started, it does not necessarily have to be done at the same time. For example, the timing at which the air trapped between the pulp mold 10 and the resin film 4 starts to expand after heating starts is confirmed in advance through an experiment, and vacuum suction is performed at a predetermined pumping speed S12 in accordance with the timing. It is also good to do.

Returning to the description of FIG. 5, the temperature of the resin film 4 increases in proportion to the passage of time from time t1 when heating by the radiation heating device 6 starts, as shown in FIG. 5(d). Then, the temperature of the resin film 4 reaches a moldable temperature C21 (160° C.) at time t2, and the heating process is completed. The time required for the heating process (time from time t1 to time t2) depends on the output of the radiant heating device 6, the distance of the radiant heating device 6 from the base 52, the material of the resin film 4, etc., but in this embodiment In this case, it is about 8 seconds.

Next, the adhesion process will be explained. When the heating process is completed, as shown in FIG. 5(b), vacuum suction by the vacuum pump 7 is performed at the maximum pumping speed S11. This vacuum suction is performed by closing the second on-off valve 9 to cut off the second pipe 11B, and at the same time opening the first on-off valve 8 to open the first pipe 11A. By performing vacuum suction at the maximum pumping speed S11, the resin film 4 is shaped along the shape of the pulp mold 10, as shown in FIG.

Further, at time t2, the distance of the radiant heating device 6 to the base 52 is shifted to a distance D12, as shown in FIG. 5(c). This means that the radiant heating device 6 is in the second heating position. At this time, the output of the radiation heating device 6 is in a constant state as shown in FIG. 5(a).

The temperature of the resin film 4 is cooled by the pulp mold 10 when it is shaped and comes into contact with the pulp mold 10, so that the temperature of the resin film 4 decreases to a temperature C22 as shown in FIG. 5(d). However, since the radiation heating device 6 continues to heat the resin film 4 at the second heating position, the temperature of the resin film 4 recovers to temperature C21 at time t3.

Since the second heating position is closer to the radiant heating device 6 and the resin film 4 than the first heating position, the amount of heat that the radiant heating device 6 gives to the resin film 4 can be increased. Therefore, the time required (time from time t2 to time t3) to radiantly heat the resin film 4, which has cooled down by contacting the pulp mold 10, until it reaches the temperature C21 again is conventionally required. (the time from time t2 to time t5 in FIG. 7(d)). Specifically, this is approximately 20 to 60% shorter than the time required in the past.

Moreover, when bonding the resin film 4 to the pulp mold 10, the amount of heat given by the radiation heating device 6 to the resin film 4 can be increased. Therefore, the amount of temperature decrease (the amount of decrease from temperature C21 to temperature C22) of the resin film 4 due to contact with the pulp mold 10 can be suppressed. Specifically, compared to the conventional temperature decrease amount (the decrease amount from temperature C21 to temperature C22 in FIG. 7(d)), the decrease amount was about 20 to 60%. This makes it possible to reduce the temperature difference that occurs between the part of the resin film 4 that is in contact with the pulp mold 10 and the part that is not in contact with the fiber molded body, and stabilizes the adhesion of the resin film 4 to the pulp mold 10. It becomes possible to do this by

Returning to the explanation of FIG. 5, after the bonding process is started, heating by the radiation heating device 6 and vacuum suction by the vacuum pump 7 are continued until time t4. This is to more reliably adhere and adhere the resin film 4 to the pulp mold 10.

At time t4, the radiant heating device 6 stops outputting, as shown in FIG. 5(a). At the same time, the radiation heating device 6 returns to the first heating position, as shown in FIG. 5(c). Note that it is not necessarily necessary to return to the first heating position, and it may be moved to a position farther away from the base 52 than the first heating position. Further, at time t4, the first on-off valve 8 is closed and the first pipe 11A is cut off, thereby stopping the vacuum suction as shown in FIG. 5(b). With this, the adhesion process is completed. The time required for the bonding process (time from time t2 to time t4) depends on the output of the radiant heating device 6, the distance of the radiant heating device 6 from the base 52, the thickness and material of the resin film 4, and the density (transparent) of the pulp mold 10. In this embodiment, the time is approximately 6 to 10 seconds, although it depends on the weather (temperature) and the like.

As mentioned above, the time required to radiantly heat the resin film 4 that has cooled down by contacting the pulp mold 10 until it reaches the temperature C21 again (the time from time t2 to time t3) is conventionally required. The time required for the bonding process (from time t2 to time t4) is shorter than the time required for the conventional bonding process (time from time t2 to time t5 in FIG. 7). This is about 20 to 60% shorter than the time (from t2 to time t6), which improves manufacturing efficiency.

After the bonding process is completed, the pulp mold 10 to which the resin film 4 is bonded is removed from the base 52. This work of removing the pulp mold 10 to which the resin film 4 is adhered may be performed manually by an operator, or may be performed by an automatic conveyance device or the like.

The heating process and bonding process described above are automatically performed by a control program stored in a control device (not shown) connected to the thermoforming device 1.

<Second Embodiment> Regarding a thermoforming apparatus according to a second embodiment, only the points different from the thermoforming apparatus 1 according to the first embodiment will be described.

The thermoforming device according to the second embodiment has the same configuration as the thermoforming device 1 according to the first embodiment shown in FIG. 1, but the second heating position of the radiant heating device 6 is as shown in FIG. The second heating position of the thermoforming apparatus 1 according to the first embodiment is different from the second heating position of the thermoforming apparatus 1 according to the first embodiment, and the second heating position of the thermoforming apparatus according to the second embodiment is closer to the radiant heating apparatus 6 than the first heating position. The distance from the base 52 is set far. That is, the radiation heating device 6 moves away from the resin film 4 at the stage of transition from the heating process to the bonding process.

When the radiant heating device 6 radiantly heats the resin film 4 in the bonding process, the pulp mold 10 may be excessively heated and burnt depending on its material. Therefore, in the bonding process, by moving the radiant heating device 6 away from the resin film 4, the amount of heat that the radiant heating device 6 gives to the pulp mold 10 is reduced. Thereby, it is possible to prevent the pulp mold 10 from being heated excessively.

As explained above, according to the thermoforming apparatus 1 according to the present embodiment,
(1) Includes a radiant heating device 6 and a base 52 facing the radiant heating device 6 with the resin film 4 in between, and the radiant heating device 6 radiantly heats the resin film 4 to a predetermined temperature C21 at which it can be molded. In the thermoforming apparatus 1 for performing a heating process for heating the resin film 4 and a bonding process for bonding the radiation-heated resin film 4 to the fiber molded body (pulp mold 10 ) placed on the base 52 , the resin film 4 is bonded to the outer periphery (flange portion 103) of the adhesive surface 104 of the fiber molded body (pulp mold 10) to which the resin film 4 is bonded before performing the heating process and the bonding process. It is characterized by being cut in a shape that follows the outer shape of the portion 103).

According to the thermoforming apparatus 1 described in (1), the resin film 4 is attached to the outside of the adhesive surface 104 of the fiber molded article (pulp mold 10) to which the resin film 4 is attached before performing the heating process and the adhesive process. Since the resin film 4 is cut into a shape along the outer shape of the outer circumferential edge (flange portion 103) while being adhered to the outer circumferential edge (flange portion 103), the resin film 4 is heated by the radiant heating device 6. It will be cut off before it can be used. That is, the resin film 4 can be cut in a state where the resin film 4 is not subjected to minute deformation or change in physical properties due to heating by the radiant heating device 6. Therefore, trimming accuracy can be improved.

Furthermore, if trimming accuracy can be improved, only the resin film 4 can be cut with high precision when trimming, and the resin film after the fiber molded body (pulp mold 10) has been separated can be No part of the pulp mold remains. Therefore, it is easy to recycle the resin film as a material after cutting off the fiber molded body (pulp mold 10), and even if recycling as a material is abandoned, the environmental burden at the time of disposal is reduced. be able to.

(2) In the thermoforming apparatus 1 described in (1), a pressure reducing means (vacuum pump 7) for vacuum suction between the fiber molded body (pulp mold 10) and the resin film 4; 7) includes an exhaust speed adjustment section (first piping 11A, second piping 11B, first on-off valve 8, second on-off valve 9, flow rate adjustment valve 13) that adjusts the evacuation speed for performing vacuum suction. It is characterized by.

(3) In the thermoforming apparatus 1 described in (2), the exhaust speed adjustment section (first piping 11A, second piping 11B, first on-off valve 8, second on-off valve 9, flow rate adjustment valve 13) The exhaust speed is adjusted between a first exhaust speed (predetermined exhaust speed S12) for performing vacuum suction in the process and a second exhaust speed (maximum exhaust speed S11) for performing vacuum suction in the bonding process. The second pumping speed (maximum pumping speed S11) is the pumping speed for bringing the resin film 4 into close contact with the fiber molded body (pulp mold 10), and the first pumping speed (predetermined pumping speed S12) is , the pumping speed is slower than the second pumping speed (maximum pumping speed S11).

(4) In the thermoforming apparatus 1 described in (3), the output of the radiation heating device 6 is heated to the extent necessary for the resin film 4 to reach a predetermined temperature C21 within a predetermined time (from time t1 to time t2). The heating process is performed by controlling the temperature (temperature C11) and vacuum suction at the first pumping speed (predetermined pumping speed S12) by the pressure reducing means (vacuum pump 7), and after the completion of the heating step, the pressure reducing means The present invention is characterized in that it includes a control program that performs the bonding process by performing vacuum suction using the vacuum pump 7 at a second pumping speed (maximum pumping speed S11).

Because the resin film 4 is in a state of being adhered to the outer periphery (flange portion 103) of the adhesive surface 104 to which the resin film 4 is adhered of the fiber molded body (pulp mold 10) before the heating process and the adhesion process are performed. Air is trapped between the fiber molded body (pulp mold 10) and the resin film 4. Therefore, if the heating process is performed as it is, the air trapped between the fiber molded body (pulp mold 10) and the resin film 4 will expand due to the heating by the radiant heating device 6, and the resin film 4 will move toward the radiant heating device 6 side. It swells up. Then, the distance between the radiant heating device 6 and the resin film 4 becomes narrower, and the resin film 4 is heated excessively, which may cause defects such as holes.

According to the thermoforming apparatus 1 described in (2), (3), or (4), vacuum suction is applied between the fiber molded product (pulp mold 10) and the resin film 4, and the resin film 4 is transformed into the fiber molded product ( A depressurizing means (vacuum pump 7) for bringing the pulp mold 10 into close contact with the pulp mold 10) and an evacuation speed adjustment section (first piping 11A, second piping 11B, the first on-off valve 8, the second on-off valve 9, and the flow rate adjustment valve 13). By performing vacuum suction at the first pumping speed (predetermined pumping speed S12), it is possible to prevent the resin film 4 from swelling toward the radiation heating device 6 side. This can prevent the resin film 4 from being excessively heated.

Note that this embodiment is merely an example, and does not limit the present invention in any way. Therefore, it goes without saying that various improvements and modifications can be made to the present invention without departing from the spirit thereof. For example, in the thermoforming device 1, one pulp mold 10 is placed on the base 52 and the resin film 4 is bonded thereto. It's good as well. Furthermore, although the thermoforming apparatus 1 is such that the radiant heating device 6 is located above the lower mold 5, the vertical position may be reversed.

1...Thermoforming device 4...Resin film 6...Radiation heating device 10...Pulp mold (an example of fiber molded product)
104...Adhesive surface 103...Flange part (example of outer periphery)

(1) A heating step comprising a radiant heating device and a base facing the radiant heating device with a resin film in between, and radiant heating the resin film to a predetermined temperature at which the resin film can be molded by the radiant heating device. and an adhesion step of adhering the radiation-heated resin film to the fiber molded article placed on the base, in which the resin film undergoes the heating step and the adhesion step. Before doing so, the fiber molded body is cut into a shape along the outer shape of the outer peripheral edge while being adhered to the outer peripheral edge of the adhesive surface to which the resin film is bonded, and the fiber molded body and the resin are comprising a pressure reducing means for vacuum suction between the film and an evacuation speed adjustment section for adjusting an evacuation speed of the pressure reduction means for performing the vacuum suction; adjusting the evacuation speed between a first evacuation speed for performing the vacuum suction in the bonding step and a second evacuation speed for performing the vacuum suction in the bonding step; The first pumping speed is characterized in that the pumping speed is for bringing the film into close contact with the fiber molded body, and the first pumping speed is slower than the second pumping speed.

(4) In the thermoforming apparatus according to ( 1 ), the output of the radiation heating device is controlled to a heating temperature necessary for the resin film to reach the predetermined temperature within a predetermined time, and the pressure reduction The means performs the heating step by performing the vacuum suction at the first evacuation speed, and after the completion of the heating step, the decompression means performs the vacuum suction at the second evacuation speed, thereby performing the bonding step. The present invention is characterized by comprising a control program that performs the following.

According to the thermoforming apparatus described in (1) or (4), there is provided a pressure reducing means for applying vacuum suction between the fiber molded body and the resin film and bringing the resin film into close contact with the fiber molded body, and a vacuum of the pressure reducing means. and an exhaust speed adjustment section that adjusts the exhaust speed for performing suction. , it is possible to prevent the resin film from swelling toward the radiation heating device. This can prevent the resin film from being excessively heated. The first pumping speed depends on the output of the radiant heating device, the volume of the fiber molded body, etc., but the speed at which the resin film does not swell toward the radiant heating device is determined in advance through experiments. It is something that can be done.

Claims (4)

a heating step for radiant heating the resin film to a predetermined temperature at which the resin film can be molded by the radiation heating device; In a thermoforming device for performing an adhesion step of adhering the heated resin film to the fiber molded body placed on the base,
Before performing the heating step and the bonding step, the resin film is adhered to the outer periphery of the bonding surface of the fiber molded article to which the resin film is bonded, and is shaped into a shape that follows the outer shape of the outer periphery. being severed;
A thermoforming device featuring: The thermoforming device according to claim 1,
a pressure reducing means for vacuum suction between the fiber molded body and the resin film;
an exhaust speed adjustment section that adjusts an exhaust speed for performing the vacuum suction of the pressure reducing means;
to have
A thermoforming device featuring: The thermoforming apparatus according to claim 2,
The evacuation speed adjustment unit adjusts the evacuation speed between a first evacuation speed for performing the vacuum suction in the heating step and a second evacuation speed for performing the vacuum suction in the bonding step. thing,
the second exhaust speed is an exhaust speed for bringing the resin film into close contact with the fiber molded body;
the first pumping speed is slower than the second pumping speed;
A thermoforming device featuring: The thermoforming apparatus according to claim 3,
The output of the radiation heating device is controlled to a heating temperature necessary for the resin film to reach the predetermined temperature within a predetermined time, and the vacuum suction is performed at the first pumping speed by the pressure reducing means. The heating step is performed by
comprising a control program that performs the bonding step by performing the vacuum suction at the second pumping speed by the depressurizing means after the heating step is completed;
A thermoforming device featuring:

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