JP7249070B1 - thermoforming equipment - Google Patents

Abstract

A thermoforming apparatus capable of improving trimming accuracy and reducing environmental load is provided. A radiant heating device 6 and a base 52 facing the radiant heating device 6 with a resin film 4 therebetween are provided, and the radiant heating device 6 heats the resin film 4 to a predetermined temperature C21 at which the resin film 4 can be molded. and a bonding step of bonding the radiantly heated resin film 4 to the pulp mold 10 placed on the base 52. And before performing the adhesion step, the resin film 4 is adhered to the flange portion 103 of the adhesion surface 104 of the pulp mold 10, and cut into a shape along the outer shape of the flange portion 103. [Selection drawing] Fig. 1

Description

The present invention includes a radiant heating device and a base that faces the radiant heating device with a resin film sandwiched therebetween, 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 a bonding step of bonding a radiantly heated resin film to a fiber molded body placed on a base.

Conventionally, plastic containers have been used as food packaging containers, but plastic containers are considered to cause environmental pollution because they do not naturally decompose when discarded. Under such circumstances, fiber moldings such as pulp molds, which are naturally decomposed even if discarded, are expected to reduce environmental pollution, and are increasingly being used as packaging containers for food. .

When the fiber molded body is used as a packaging container for food, if the food is filled as it is, water and oil contained in the food may permeate the fiber molded body and cause leakage. For this reason, it is common to adhere a thermoplastic resin film to the surface of the fiber molding that comes into contact with food, thereby imparting water resistance and oil resistance to the fiber molding. For example, Patent Literature 1 discloses a paper container to which a resin film is adhered.

Adhesion of the resin film to the fiber molded body is performed by, for example, a radiation heating device 6 for heating the resin film 4 and a pulp mold 10 (an example of a fiber molded body) for placing thereon, as shown in FIG. A thermoforming apparatus 100 having a lower mold 5 is used.

The thermoforming apparatus 100 heats the resin film 4 to a predetermined moldable temperature by the radiation heating device 6, and bonds the resin film 4 softened by the radiation heating to the pulp mold 10 placed on the lower mold 5. It is a device for The process of radiantly heating the resin film 4 to a predetermined moldable temperature by the radiant heating device 6 is called a heating process. The process of adhering is called an adhering process.

The shape of the pulp mold 10 is, for example, an oval bottom 101 in a plan view (viewed from above in FIG. 6), a peripheral wall 102 rising from the peripheral edge 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. The inner surface of the pulp mold 10 on the radiant heating device 6 side (upper side in FIG. 6) is a bonding surface 104 to which the resin film 4 is bonded.

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.degree. The surface of the resin film 4 facing the pulp mold 10 is provided with an adhesive layer (not shown) made of a heat sealing agent or the like in order to improve adhesion with the pulp mold 10 .

The lower mold 5 is composed of a formwork 51 , a pedestal 53 and a base 52 . The formwork 51 has a frame 512 and a peripheral wall 511 erected on the frame 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-suck the inside of the mold 51 through the vent 512a.

A pedestal 53 for mounting the base 52 is fixed above the pedestal 512 , surrounded by the peripheral wall 511 . The pedestal 53 has a plurality of communication paths 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 formed in the shape of the pulp mold 10 on the end face on the side of the radiation heating device 6 (upper side in the vertical direction VT). Furthermore, the base 52 has a plurality of vacuum vents 522 opening to the mounting surface 521 . When the inside of the formwork 51 is vacuum-sucked by the vacuum pump 7 , the mounting surface 521 side can be vacuum-sucked through the communicating passage 531 and the vacuum vent 522 . In the state shown in FIG. 6, the resin film 4 can be adhered to the adhesion surface 104 of the pulp mold 10 without gaps by vacuum-sucking the mounting surface 521 side. Since the pulp mold 10 has air permeability, even if the pulp mold 10 is mounted on the mounting surface 521, pressurization and vacuum suction on the mounting surface 521 side are not hindered.

The radiation heating device 6 is positioned to face the lower die 5 with the resin film 4 interposed therebetween. The position of the radiation heating device 6 shown in FIG. 1 is the heating position for performing radiation heating of the resin film 4 in the heating step. The distance D11 of the radiation heating device 6 from the base 52 at the heating position is determined based on the output of the radiation heating device 6, the material of the resin film 4, the target time required 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 with reference to FIG. 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 of the pumping speed of the vacuum pump 7 in the bonding process and the heating process. FIG. 7(c) is a time chart for the position of the radiation heating device 6 (the distance of the radiation heating device 6 from the base 52) in the bonding process and the heating process. FIG. 7(d) is a graph showing how the temperature of the resin film 4 changes during the bonding process and the heating process.

As shown in FIG. 7(a), the output of the radiation heating device 6 is started at time t1, and the heating process is started. The output of the radiation heating device 6 is constant at temperature C11 throughout the heating process and the bonding process. Although the value of the temperature C11 is arbitrarily set depending on the performance of the radiation heating device 6, the material of the resin film 4 to be heated, etc., the temperature of the radiation heating device 6 is set to 600° C. here. . Further, the distance of the radiation heating device 6 to the base 52 is constant at a distance D11 through 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 rises in proportion to the passage of time from time t1 when heating by the radiation heating device 6 is started. Then, the temperature of the resin film 4 reaches the moldable temperature C21 (160° C.) at time t2, and the heating process is completed. The time required for the heating process (the time from time t1 to time t2) depends on the output of the radiation heating device 6, the distance of the radiation heating device 6 from the base 52, the thickness and material of the resin film 4, and the like. about 8 seconds.

After completing the heating process, the thermoforming apparatus 100 performs the bonding process. Specifically, as shown in FIG. 7(b), vacuum suction by the vacuum pump 7 is performed at a maximum pumping speed S11 corresponding 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 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 from the base 52, the material of the resin film 4, and the like. seconds.

The pulp mold 10 to which the resin film 4 is adhered is carried out from the thermoforming apparatus 100 by feeding 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 . Since the resin film 4 is continuously adhered to the pulp mold 4 in this way, a plurality of pulp molds 10 are aligned in the horizontal direction HZ and hung from the resin film 4 fed out along the horizontal direction HZ. state. The pulp molds 10 are conveyed to the trimming process while hanging from the resin film 4 , and in the trimming process, the pulp molds 10 lined up in the horizontal direction HZ are cut off from the resin film 4 one by one.

Japanese Patent Application Laid-Open No. 2001-233317

When the resin film 4 is shaped along the shape of the pulp mold 10 in the bonding step after the heating step, as shown in FIG. A green portion 42 is formed around the portion 41 . This unmolded portion 42 is a portion of the resin film 4 that remains without being shaped. However, due to the heating by the radiant heating device 6 in the heating process and the bonding process and the removal from the thermoforming apparatus 100, the unformed portion 42 may be slightly deformed or changed in physical properties. In this case, the pitch between the pulp molds 10 arranged in front and behind in the horizontal direction HZ is shifted, which may adversely affect the accuracy of trimming performed after the resin film 4 is adhered.

Also, when trimming, it is difficult to cut only the resin film 4 with high accuracy, so the tip of the flange portion 103 is cut as shown by a cutting line 15 that virtually indicates the position to be trimmed. Thus, the pulp mold 10 is separated from the resin film 4 . The resin film 4 after the pulp mold 10 is cut off is wound up and discarded, but since the tip of the cut flange portion 103 remains adhered, separation is difficult. If the sorting is difficult, it becomes difficult to reuse as a material, and the environmental load at the time of disposal is large.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a thermoforming apparatus capable of improving the trimming accuracy and reducing the 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 sandwiched therebetween, and radiantly heating the resin film to a predetermined temperature at which the resin film can be molded by the radiant heating device. and a bonding step of bonding the radiantly heated resin film to the fiber molded body placed on the base, wherein the resin film undergoes the heating step and the bonding step. Before performing, the fiber molded body is cut into a shape along the outer peripheral edge in a state of being adhered to the outer peripheral edge of the adhesive surface for bonding the resin film, and the fiber molded body and the resin decompressing means for vacuum-sucking a film, and an exhaust speed adjusting section for adjusting the exhaust speed for performing the vacuum suction of the decompressing means, wherein the exhaust speed adjusting unit performs the heating step. adjusting the exhaust speed between the first exhaust speed for performing the vacuum suction and the second exhaust speed for performing the vacuum suction in the bonding step, and the second exhaust speed is the resin The first exhaust speed is slower than the second exhaust speed.

According to the thermoforming apparatus described in (1), before the heating step and the bonding step, the resin film is adhered to the outer periphery of the bonding surface of the fiber molded body to which the resin film is bonded. Since the resin film is characterized by being cut into a shape along the outer shape of the peripheral edge, the resin film is cut before being heated by the radiant heating device. That is, the resin film can be cut in a state in which the resin film is not slightly deformed or changed in physical properties due to heating by the radiant heating device. Therefore, it is possible to improve the trimming accuracy.

Further, if it is possible to improve the trimming accuracy, it will be possible to cut only the resin film with high accuracy when performing trimming, and the resin film after cutting the fiber molded body will be a part of the fiber molded body. does not remain. Therefore, it is easy to recycle the resin film as a material after cutting off the fiber molded body, and even if recycling as a material is abandoned, it is possible to reduce the environmental load at the time of disposal.

(4) In the thermoforming apparatus described in ( 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 reduced pressure is The heating step is performed by performing the vacuum suction at the first exhaust speed by the means, and the bonding step is performed by performing the vacuum suction at the second exhaust speed by the decompression means after the completion of the heating step. characterized by comprising a control program for performing

Since the resin film is in a state of being adhered to the outer peripheral edge of the adhesive surface of the fiber molded body to which the resin film is bonded before performing the heating process and the bonding process, air is present between the fiber molded body and the resin film. trapped. Therefore, if the heating process is performed as it is, the air trapped between the fiber molding and the resin film expands due to the heating of the radiant heating device, and the resin film expands toward the radiant heating device. As a result, the distance between the radiant heating device and the resin film is narrowed, the resin film is excessively heated, and there is a possibility that a defect such as a hole is generated.

According to the thermoforming apparatus described in (1) or (4), the space between the fiber molded body and the resin film is vacuum-sucked to bring the resin film into close contact with the fiber molded body; and an exhaust speed adjustment unit that adjusts the exhaust speed for performing suction. , the resin film can be prevented from swelling toward the radiant heating device. This can prevent the resin film from being excessively heated. The first exhaust speed depends on the output of the radiant heating device, the volume of the fiber molding, etc., but the speed at which the resin film does not swell toward the radiant heating device is determined in advance by experiment. It is something that can be done.

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

While showing the structure of the thermoforming apparatus which concerns on this embodiment, it is a figure showing the state in which a thermoforming apparatus exists in a heating process. It is a figure showing the state in which the thermoforming apparatus which concerns on this embodiment is in a bonding process. It is an enlarged view which expanded the flange part (an example of an outer peripheral edge) of a pulp mold (an example of a fiber molding). It is the top view seen from the thermal radiation part side of the radiation heating apparatus. (a) is a time chart of the output of the radiant heating device in the bonding process and the heating process. (b) is a time chart of the pumping speed of the vacuum pump in the bonding process and the heating process. (c) is a time chart for the position of the radiant heating device in the bonding process and the heating process. (d) is a graph showing the temperature change of the resin film in the bonding process and the heating process. It is a figure which shows the structure of the thermoforming apparatus based on a prior art. (a) is a time chart of outputs of a radiation heating device in a conventional bonding process and a heating process. (b) is a time chart of exhaust speed of a vacuum pump in a bonding process and a heating process according to the prior art; (c) is a time chart for the position of the radiant heating device in the bonding process and the heating process according to the prior art; (d) is a graph showing temperature changes of a resin film in a bonding process and a heating process according to the prior art. FIG. 3 is an enlarged view of the flange portion 103 of the pulp mold 10 to which the resin film is adhered by the conventional thermoforming apparatus.

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 apparatus 1 according to this embodiment and showing a state in which the thermoforming apparatus 1 is in a heating process. FIG. 2 is a diagram showing a state in which the thermoforming apparatus 1 according to this embodiment is in a bonding process. FIG. 3 is an enlarged view of the flange portion 103 (an example of the outer peripheral edge) of the pulp mold 10 (an example of the fiber molding). The resin film 4 in FIG. 3 is before trimming along the outer shape of the flange portion 103 . A cutting line 14 in FIG. 3 is a line that virtually indicates the position for trimming. FIG. 4 is a plan view of the radiation heating device 6 as viewed from the heat radiating portion 6a side.

<Regarding the configuration of the thermoforming device>
The thermoforming apparatus 1 according to the first embodiment, as shown in FIG. It is an apparatus for radiant heating and bonding the resin film 4 softened by the radiant heating to the pulp mold 10 placed on the lower mold 5 . The process of radiantly heating the resin film 4 to a predetermined moldable temperature by the radiant heating device 6 is called a heating process. The process of adhering is called an adhering process.

The pulp mold 10 is a packaging container for food, for example, which is molded from a pulp material to have a thickness of about 0.5 to 3 mm. The shape of the pulp mold 10 is not particularly limited. and a flange portion 103 projecting outward from the pulp mold 10 from the upper end of the . Further, the inner surfaces of the bottom portion 101 and the peripheral wall portion 102 of the pulp mold 10 on the radiation heating device 6 side (upper side in FIG. 1) are bonding surfaces 104 to which the resin film 4 is bonded. As the pulp material, wood pulp (limited to virgin materials) and non-wood pulp (limited to virgin materials) made from reeds, sugar cane, bamboo, etc. are used. However, if the pulp mold 10 is not used for food, as the pulp material, in addition to the above, recycled wood pulp and non-wood pulp, and waste paper pulp using waste paper such as newspapers, magazines, and cardboard may be used. good. Since the pulp mold 10 is an assembly of fibers using pulp material as described above, it has air permeability. Air can pass between

The resin film 4 is a thermoplastic film made of polypropylene (PP). However, the material is not limited to polypropylene (PP) as long as it conforms to food sanitation standards (for example, standards stipulated in the Food Sanitation Law). For example, olefin-based resins such as polyethylene (PE), polyester-based resins such as polyethylene terephthalate (PET), ethylene-vinyl acetate copolymers, and the like can be used.

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

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

In addition, before being shaped by the thermoforming apparatus 1, the resin film 4 is cut in advance along the outline of the pulp mold 10 in a plan view (viewed from above in FIG. 1). Specifically, as shown in FIG. 1, it is cut in advance along the outer periphery of the flange portion 103 while being adhered only to the flange portion 103 of the pulp mold 10 . In other words, the resin film 4 is cut before being heated by the radiation heating device 6, and the resin film 4 is not slightly deformed or changed in physical properties due to the heating of the radiation heating device 6. Film 4 can be cut. Therefore, it is possible to improve the trimming accuracy.

Also, if the trimming accuracy can be improved, only the resin film 4 can be cut with high accuracy when trimming. Specifically, conventionally, 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 indicated by the cutting line 15 in FIG. However, since the thermoforming apparatus 1 according to the present embodiment can improve the trimming accuracy, as shown by the cutting line 14 in FIG. It is possible to cut only the resin film 4 with high precision by aiming at the boundary portion between the surrounding resin film 4 and the portion where the resin film 4 is not adhered. Therefore, part of the pulp mold does not remain on the resin film after the fiber molded body (pulp mold 10) is separated. Therefore, it is easy to recycle as a resin film material after separating the fiber molded body (pulp mold 10), and even if recycling as a material is abandoned, the environmental load can be reduced when discarding. be able to.

The bonding and cutting of the resin film 4 only to the flange portion 103 may be performed as a preliminary process by a device separate from the thermoforming device 1, or the thermoforming device 1 may be provided with a cutting device such as a Thomson blade. Alternatively, the resin film 4 may be adhered only to the flange portion 103 by the thermoforming apparatus 1 and cut along the outer circumference of the flange portion 103 by the cutting device.

The resin film 4 as described above is heated to about 160° C. by the radiant 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. and adhered to the adhesion surface 104 . The pulp mold 10 is provided with water resistance, oil resistance, and heat resistance by adhering the resin film 4 thereto.

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

A pedestal 53 for mounting the base 52 is fixed above the pedestal 512 , surrounded by the peripheral wall 511 . The pedestal 53 has a plurality of communication paths 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 formed in the shape of the pulp mold 10 on the end face on the side of the radiation heating device 6 (upper side in the vertical direction VT). Furthermore, the base 52 has a plurality of vacuum vents 522 opening to the mounting surface 521 . When the inside of the formwork 51 is vacuum-sucked by the vacuum pump 7 , the mounting surface 521 side can be vacuum-sucked through the communicating passage 531 and the vacuum vent 522 . Since the pulp mold 10 has air permeability, even if the pulp mold 10 is mounted on the mounting surface 521, pressurization and vacuum suction on the mounting surface 521 side are not hindered. Therefore, in the state shown in FIG. 1, by vacuum-sucking the placement surface 521 side, the space between the pulp mold 10 and the resin film 4 is vacuum-sucked, and the resin film 4 is moved to the gap between the adhesive surface 104 of the pulp mold 10. It becomes possible to bond without

A vacuum pump 7 is connected to the air vent 512a of the lower die 5 via a first pipe 11A and a second pipe 11B which 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, when the first on-off valve 8 is closed, the first pipe 11A is shut off.

A second on-off valve 9 and a flow control valve 13 are arranged in this order from the vacuum pump 7 side on the second pipe 11B. 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, closing the second on-off valve 9 shuts off the second pipe 11B. In addition, the flow control valve 13 is adjustable in valve opening degree, and by adjusting the valve opening degree, it is possible to adjust the exhaust speed during vacuum suction by the second pipe 11B.

The vacuum pump 7 is always in operation while the thermoforming apparatus 1 is in operation. Vacuum suction can be performed at the maximum pumping speed S11 (see FIG. 5B (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 exhaust speed (for example, a predetermined Vacuum suction can be performed at the exhaust speed S12 (see FIG. 5B (an example of the first exhaust speed))). In other words, the first pipe 11A, the second pipe 11B, the first on-off valve 8, the second on-off valve 9, and the flow control valve 13 function as an exhaust speed adjusting section that adjusts the exhaust speed of the vacuum pump 7.

The radiation heating device 6 is positioned to face the lower die 5 with the resin film 4 interposed therebetween. The radiation heating device 6 has a heat radiating portion 6a at the end face on the side of the lower die 5, and the heat radiating portion 6a is formed of a plurality of heater elements 61 as shown in FIG. Specifically, in the radiation heating device 6, rows of heater elements 61 in which six heater elements 61 (octagonal in plan view) are arranged adjacent to each other in the X direction are arranged in five rows adjacent to each other in the Y direction. , with a total of 30 heater elements 61 . These 30 heater elements 61 constitute a heat radiation portion 6a. It should be noted that the X direction in FIG. 4 is a direction parallel to the horizontal direction HZ in FIGS. Also, the number of heater elements 61 is not limited to the above, and is merely an example.

4, the radiation heating device 6 is provided with a temperature sensor 62 so as to be surrounded by four heater elements 61 located in the central region of the radiation 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 in the heating process and the bonding process.

The radiation heating device 6 can be vertically moved along the vertical direction VT by an elevating means 12 (for example, an air cylinder), and can be moved between a first heating position and a second heating position. . The position of the radiation heating device 6 shown in FIG. 1 is the first heating position for performing radiation heating of the resin film 4 in the heating process. The position of the radiation heating device 6 shown in FIG. 2 is the second heating position for performing radiation heating of the resin film 4 in the bonding process. A distance D12 from the radiation heating device 6 to the base 52 at the second heating position is set smaller than D11 from the radiation heating device 6 to the base 52 at the distance first heating position. Since the radiation heating device 6 is movable between the first heating position and the second heating position in this way, the distance of the radiation heating device 6 to the resin film 4 is variable. The distance D11 of the radiation heating device 6 to the base 52 at the first heating position and the distance D12 of the radiation heating device 6 to the base 52 at the second heating position depend on the output of the radiation heating device 6 and the thickness of the resin film 4. It is determined based on the material, the target time required for the heating process and the bonding process, and the like.

<Regarding the heating process and the bonding process>
A heating process and a bonding process performed using the thermoforming apparatus 1 having the above configuration will be described with reference to FIG. FIG. 5(a) 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 of the pumping speed of the vacuum pump 7 in the bonding process and the heating process. FIG. 5(c) is a time chart for the position of the radiation heating device 6 (the distance of the radiation heating device 6 from the base 52) in the bonding process and the heating process. FIG. 5(d) is a graph showing how the temperature of the resin film 4 changes during the bonding process and the heating process.

Before starting the heating process and the bonding process, the resin film 4 is adhered only to the flange portion 103 of the pulp mold 10, and the resin film 4 is placed along the outline of the pulp mold 10 in plan view. to cut. Then, as shown in FIG. 1, the pulp mold 10 is placed on the placement surface 521 of the base 52 . The operation 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 conveying device or the like.

Further, before starting the heating process and the bonding process, the first on-off valve 8 and the second on-off valve 9 are closed, and the first pipe 11A and the second pipe 11B are shut off, and the vacuum pump 7 is operated. back. Furthermore, the valve opening degree of the flow control 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. Details of the predetermined exhaust speed S12 will be described later.

First, the heating process will be described. As shown in FIG. 5(a), the output of the radiation heating device 6 is started at time t1, and the heating process is started. The output of the radiation heating device 6 is constant at temperature C11 throughout the heating process and the bonding process. The value of the temperature C11 is arbitrarily set depending on the performance of the radiation heating device 6, the material of the resin film 4 to be heated, etc., and is not particularly limited, but in the present embodiment, the radiation heating device 600° C., which is the maximum output of No. 6. Further, the distance of the radiation heating device 6 to the base 52 is a distance D11 as shown in FIG. 5(c). This means that the radiation heating device 6 is in the first heating position.

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

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 the resin film 4 is heated by the radiant heating device 6 as it is, the air trapped between the pulp mold 10 and the resin film 4 expands, causing the resin film 4 to swell toward the radiant heating device 6 (upward in FIG. 1). put away. As a result, the distance between the radiation heating device 6 and the resin film 4 is narrowed, and the resin film 4 is excessively heated, which may cause defects such as holes. Therefore, as described above, vacuum suction is performed at the predetermined exhaust speed S12 to prevent the resin film 4 from swelling toward the radiation heating device 6 and prevent the resin film 4 from being excessively heated. ing.

The predetermined exhaust speed S12 depends on the output of the radiation heating device 6, the volume of the pulp mold 10, and the like. keep asking Then, the valve opening degree of the flow control valve 13 is adjusted according to the predetermined exhaust speed S12 obtained by experiment. It is desirable that the resin film 4 is kept as horizontal as possible by performing vacuum suction at a predetermined exhaust speed S12. This is for uniformly heating the entire resin film 4 . However, it does not necessarily have to be kept horizontal, and it is sufficient if the resin film 4 does not swell toward the radiant heating device 6 side. For example, the resin film 4 may be deformed concavely toward the pulp mold 10 to the extent that the resin film 4 is not shaped by performing vacuum suction at a predetermined exhaust speed S12. Also, the vacuum suction at the predetermined exhaust speed S12 is performed from time t1 at the same time as the heating process is started, but it is not necessarily at the same time. For example, the timing at which the air confined between the pulp mold 10 and the resin film 4 begins to expand after the start of heating is experimentally confirmed in advance, and vacuum suction is performed at a predetermined exhaust speed S12 in accordance with this timing. It's okay 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 is started, as shown in FIG. 5(d). Then, the temperature of the resin film 4 reaches the 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 this embodiment is about 8 seconds.

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

At time t2, the distance of the radiation heating device 6 from the base 52 is shifted to the distance D12 as shown in FIG. 5(c). This means that the radiation 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 brought into contact with the pulp mold 10, so that the temperature drops to 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 the temperature C21 at time t3.

At the second heating position, since the distance between the radiation heating device 6 and the resin film 4 is shorter than at the first heating position, the amount of heat given to the resin film 4 by the radiation heating device 6 can be increased. Therefore, the time (time from time t2 to time t3) required for radiantly heating the resin film 4, which has cooled by contacting the pulp mold 10, to reach the temperature C21 again has conventionally been required. shorter than the time (the time from time t2 to time t5 in FIG. 7(d)). Specifically, it is about 20 to 60% shorter than the time required conventionally.

Moreover, when the resin film 4 is adhered to the pulp mold 10, the amount of heat given to the resin film 4 by the radiation heating device 6 can be increased. Therefore, the amount of temperature drop (the amount of drop from temperature C21 to temperature C22) due to contact of the resin film 4 with the pulp mold 10 can be suppressed. Specifically, the amount of decrease was about 20 to 60% of the conventional amount of temperature decrease (the amount of decrease from temperature C21 to temperature C22 in FIG. 7(d)). As a result, the temperature difference between the portion of the resin film 4 that is in contact with the pulp mold 10 and the portion that is not in contact with the fiber molding can be reduced, and the adhesion of the resin film 4 to the pulp mold 10 is stabilized. It is possible to do

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

At time t4, the radiation 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). In addition, it is not always necessary to return to the first heating position, and it may be moved to a position further away from the base 52 than the first heating position. Further, at time t4, the first on-off valve 8 is closed to cut off the first pipe 11A, thereby stopping the vacuum suction as shown in FIG. 5(b). This completes the bonding process. The time required for the bonding process (the 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 (transparency) of the pulp mold 10. In the present embodiment, it is about 6 to 10 seconds, although it depends on factors such as temperature.

As described above, the time (time from time t2 to time t3) required for radiantly heating the resin film 4, which has cooled by contacting the pulp mold 10, to reach the temperature C21 again is conventionally required. 7D), the time required for the bonding process (time t2 to time t4) is shorter than the time required for the conventional bonding process (time t5 in FIG. 7). It is about 20 to 60% shorter than the time from t2 to time t6), and the manufacturing efficiency is improved.

After the bonding step is completed, the pulp mold 10 with the resin film 4 bonded thereto is removed from the base 52 . The operation 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 conveying 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 apparatus 1 .

<Second Embodiment> Only points of a thermoforming apparatus according to a second embodiment that are different from the thermoforming apparatus 1 according to the first embodiment will be described.

The thermoforming apparatus according to the second embodiment has the same configuration as the thermoforming apparatus 1 according to the first embodiment shown in FIG. It differs 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 more connected to the radiant heating device 6 than the first heating position. The distance from the base 52 is set long. That is, the radiant heating device 6 moves away from the resin film 4 at the stage of moving from the heating process to the bonding process.

When the radiation heating device 6 radiates and heats the resin film 4 in the bonding step, the pulp mold 10 may be excessively heated and scorched depending on the material of the pulp mold 10 . Therefore, in the bonding step, the amount of heat given to the pulp mold 10 by the radiation heating device 6 is reduced by moving the radiation heating device 6 away from the resin film 4 . Thereby, it is possible to prevent the pulp mold 10 from being excessively heated.

As described above, according to the thermoforming apparatus 1 according to this embodiment,
(1) A radiation heating device 6 and a base 52 facing the radiation heating device 6 with the resin film 4 therebetween are provided, and the radiation heating device 6 radiates and heats the resin film 4 to a predetermined temperature C21 at which the resin film 4 can be molded. and a bonding step of bonding the radiantly heated resin film 4 to the fiber molding (pulp mold 10) placed on the base 52. In the thermoforming apparatus 1, the resin film 4 is bonded to the outer peripheral edge (flange portion 103) of the adhesive surface 104 for bonding the resin film 4 of the fiber molded body (pulp mold 10) before performing the heating step and the bonding step. It is characterized by being cut into a shape along the outer shape of the portion 103).

According to the thermoforming apparatus 1 described in (1), the resin film 4 is formed on the outside of the bonding surface 104 of the fiber molding (pulp mold 10) to which the resin film 4 is bonded before performing the heating step and the bonding step. Since the resin film 4 is characterized by being adhered to the peripheral edge (flange portion 103) and cut into a shape along the outer shape of the peripheral edge (flange portion 103), the resin film 4 is heated by the radiant heating device 6. It is cut before the That is, the resin film 4 can be cut in a state in which the resin film 4 is not slightly deformed or changed in physical properties due to heating by the radiant heating device 6 . Therefore, it is possible to improve the trimming accuracy.

Further, if it is possible to improve the trimming accuracy, it will be possible to cut only the resin film 4 with high accuracy when performing trimming. No part of the pulp mold remains. Therefore, it is easy to recycle as a resin film material after separating the fiber molded body (pulp mold 10), and even if recycling as a material is abandoned, the environmental load can be reduced when discarding. be able to.

(2) In the thermoforming apparatus 1 described in (1), pressure reduction means (vacuum pump 7) for vacuum suction between the fiber molded body (pulp mold 10) and the resin film 4, pressure reduction means (vacuum pump 7) An exhaust speed adjustment unit (first pipe 11A, second pipe 11B, first on-off valve 8, second on-off valve 9, flow rate adjustment valve 13) that adjusts the exhaust speed for performing vacuum suction. characterized by

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

(4) In the thermoforming apparatus 1 described in (3), the output of the radiation heating device 6 is set to the heating required for the resin film 4 to reach a predetermined temperature C21 within a predetermined time (from time t1 to time t2). While controlling the temperature (temperature C11), the heating step is performed by performing vacuum suction at the first exhaust speed (predetermined exhaust speed S12) by the pressure reducing means (vacuum pump 7), and after the heating step is completed, the pressure reducing means (Vacuum pump 7) is characterized by having a control program for performing a bonding process by performing vacuum suction at a second exhaust speed (maximum exhaust speed S11).

Since the resin film 4 is in a state of being adhered to the outer peripheral edge (flange portion 103) of the adhesion surface 104 of the fiber molding (pulp mold 10) to which the resin film 4 is adhered before the heating step and the adhesion step are performed. , air is trapped between the fiber molding (pulp mold 10) and the resin film 4; Therefore, if the heating process is performed as it is, the air trapped between the fiber compact (pulp mold 10) and the resin film 4 expands due to the heating of the radiant heating device 6, and the resin film 4 moves toward the radiant heating device 6 side. It swells up. As a result, the distance between the radiation heating device 6 and the resin film 4 is narrowed, and the resin film 4 is excessively heated, which may cause defects such as holes.

According to the thermoforming apparatus 1 described in (2) or (3) or (4), vacuum suction is performed between the fiber molded body (pulp mold 10) and the resin film 4, and the resin film 4 is removed from the fiber molded body ( A decompression means (vacuum pump 7) for bringing the pulp mold 10 into close contact with the decompression means (vacuum pump 7), and an exhaust speed adjustment unit (first pipe 11A, second pipe 11B, the first on-off valve 8, the second on-off valve 9, and the flow regulating valve 13), for example, in the heating step, the exhaust speed is slower than the second exhaust speed (maximum exhaust speed S11) in the bonding step. By performing vacuum suction at the first exhaust speed (predetermined exhaust speed S12), it is possible to prevent the resin film 4 from swelling toward the radiation heating device 6 side. Thereby, it is possible to prevent the resin film 4 from being excessively heated.

It should be noted that this embodiment is merely an example, and does not limit the present invention in any way. Therefore, the present invention can naturally be improved and modified in various ways without departing from the scope of the invention. For example, in the thermoforming apparatus 1, one pulp mold 10 is placed on the base 52 and the resin film 4 is adhered. It is good as Furthermore, although the thermoforming apparatus 1 has the radiant heating apparatus 6 positioned above the lower mold 5, the upper and lower positions may be reversed.

DESCRIPTION OF SYMBOLS 1... Thermoforming apparatus 4... Resin film 6... Radiation heating apparatus 10... Pulp mold (an example of fiber molding)
104... Adhesion surface 103... Flange part (an example of the outer peripheral edge)

Claims (2)

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, comprising a radiant heating device and a base facing the radiant heating device with a resin film therebetween; A thermoforming apparatus for performing a bonding step of bonding 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 peripheral edge of the adhesive surface of the fiber molded body to which the resin film is attached, and is shaped along the outer shape of the outer peripheral edge. being disconnected,
decompression means for vacuum suction between the fiber molded body and the resin film;
an exhaust speed adjustment unit that adjusts an exhaust speed for performing the vacuum suction of the decompression means;
to provide
The exhaust speed adjustment unit adjusts the exhaust speed between a first exhaust speed for performing the vacuum suction in the heating step and a second exhaust speed for performing the vacuum suction in the bonding step. matter,
The second exhaust speed is an exhaust speed for adhering the resin film to the fiber molded body,
the first pumping speed is slower than the second pumping speed;
A thermoforming apparatus characterized by: The thermoforming apparatus of claim 1 , wherein
The output of the radiation heating device is controlled to a heating temperature required for the resin film to reach the predetermined temperature within a predetermined time, and the decompression means performs the vacuum suction at the first exhaust speed. The heating step is performed by
Having a control program for performing the bonding step by performing the vacuum suction at the second exhaust speed by the decompression means after the completion of the heating step;
A thermoforming apparatus characterized by:

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