Thermoforming device

Abstract

A thermoforming apparatus (1) has a radiation heating device (6) and a base (52) facing the radiation heating device (6) with a resin film (4) interposed therebetween, for performing a heating process for radiantly heating the resin film (4) to a prescribed temperature (C21) capable of being formed by the radiation heating device (6), and a bonding process for bonding the resin film (4) after being radiantly heated to a pulp molded article (10) loaded on the base (52). Before the heating process and the bonding process are performed, the resin film (4) is cut in a shape along the outer shape of a flange portion (103) of a bonding surface (104) of the resin film (4) bonded to the pulp molded article (10) in a state where the resin film (4) is bonded to the flange portion (103).

Description

Technical Field

[0001] The present invention relates to a thermoforming apparatus comprising a radiant heating device and a base facing the radiant heating device with a resin film in between, for performing a heating process and a bonding process. The heating process is used to radiate heat the resin film to a predetermined temperature at which it can be formed by means of the radiant heating device, and the bonding process is used to bond the radiantly heated resin film to a fiber molded body placed on the base. Background Technology

[0002] Plastic containers have traditionally been used for food packaging, but they do not degrade naturally after disposal, leading to concerns about environmental pollution. In this context, fibrous materials such as molded pulp, which degrade naturally even after disposal, are increasingly being used as food packaging containers, with the expectation that they can mitigate environmental pollution.

[0003] When fiber-molded bodies are used as food packaging containers, there is a risk of leakage if food is directly filled into them, as moisture or oil contained in the food may seep into the fiber-molded body. Therefore, the following treatment is usually performed: a thermoplastic resin film is bonded to the food-contacting surface of the fiber-molded body, thereby imparting water and oil resistance to the fiber-molded body. For example, Patent Document 1 discloses a paper container with a resin film bonded to it.

[0004] For example, using Figure 5 The thermoforming apparatus 100 shown is used to bond the resin film onto the fiber molded body. The thermoforming apparatus 100 includes a radiant heating device 6 for heating the resin film 4 and a lower mold 5 for placing the pulp molded part 10 (an example of the fiber molded body).

[0005] The thermoforming apparatus 100 is used to radiate heat the resin film 4 to a predetermined temperature suitable for molding using a radiant heating device 6, and to bond the radiantly heated and softened resin film 4 to the pulp molded part 10 placed on the lower mold 5. Furthermore, the process of radiantly heating the resin film 4 to the predetermined temperature suitable for molding using the radiant heating device 6 is called the heating process, and the process of bonding the radiantly heated and softened resin film 4 to the pulp molded part 10 placed on the lower mold 5 is called the bonding process.

[0006] The shape of the pulp molded part 10, for example, has a top view (from...) Figure 6 (Viewed from above) The molded pulp part 10 consists of an elongated oval bottom 101, a peripheral wall portion 102 rising from the periphery of the bottom 101, and a flange portion 103 extending from the upper end of the peripheral wall portion 102 toward the outside of the pulp molded part 10. Furthermore, the radiant heating device 6 side of the pulp molded part 10 ( Figure 6 The inner surface of the middle (top side) is the bonding surface 104 of the adhesive resin film 4.

[0007] The resin film 4 is, for example, a thermoplastic film made of polypropylene (PP). Its thickness is, for example, 80 μm. The melting point of the resin film 4 is, for example, 167°C, and it is heated to 160°C (temperature C21, reference) during the heating process, which is a predetermined temperature for molding. Figure 6 (d))) An adhesive layer (not shown) formed by a heat sealant or the like is provided on the surface of the resin film 4 facing the pulp molded part 10 to improve adhesion to the pulp molded part 10.

[0008] The lower mold 5 consists of a mold box 51, a base 53, and a platform 52. The mold box 51 has a frame 512 and a peripheral wall 511 erected on the frame 512. The frame 512 has a vent 512a extending in the vertical direction VT, and a vacuum pump 7 is connected to the vent 512a. The vacuum pump 7 can perform vacuum suction inside the mold box 51 through the vent 512a.

[0009] A base 53, surrounded by a peripheral wall 511, is fixed above the frame 512 for mounting the base 52. The base 53 has multiple connecting channels 531 that extend through the base 53 in the vertical direction VT. The base 52, surrounded by a peripheral wall 511, is mounted on the upper end face of the base 53 in the vertical direction VT for placing the pulp molded part 10.

[0010] The base 52 has a mounting surface 521, with a shape identical to that of the pulp molding part 10, passing through its end face on the side of the radiant heating device 6 (the upper side of VT in the vertical direction). Furthermore, the base 52 has multiple vacuum vents 522 formed on the mounting surface 521. When a vacuum is applied to the mold box 51 using the vacuum pump 7, vacuum can be applied to the mounting surface 521 side via the connecting channel 531 and the vacuum vents 522. Figure 5 In the state shown, vacuum suction is applied to the mounting surface 521 side, which can bond the resin film 4 to the bonding surface 104 of the pulp molded part 10 without gaps. The pulp molded part 10 is breathable, so even if the pulp molded part 10 is mounted on the mounting surface 521, it will not hinder the vacuum suction on the mounting surface 521 side.

[0011] The radiant heating device 6 is positioned facing the lower mold 5 through the resin film 4. Figure 5 The position of the radiant heating device 6 shown is the heating position used for radiant heating of the resin film 4 in the heating process. The distance D11 of the radiant heating device 6 relative to the base 52 at this heating position is determined based on the output of the radiant heating device 6, the raw material of the resin film 4, the target time required for the heating process and the bonding process, etc.

[0012] use Figure 7 The heating and bonding processes performed using the thermoforming apparatus 100 with the above configuration will be described. Figure 7(a) is a time diagram of the output of the radiant heating device 6 in the bonding and heating processes. Figure 7 (b) is a time graph showing the exhaust speed of vacuum pump 7 in the bonding and heating processes. Figure 7 (c) is a time diagram related to the position of the radiant heating device 6 (distance D11 of the radiant heating device 6 relative to the base 52) in the bonding and heating processes. Figure 7 (d) is a graph showing the temperature changes of the resin film 4 during the bonding and heating processes.

[0013] like Figure 7 As shown in (a), the heating process begins at time point t1 with the output of the radiant heating device 6. The output of the radiant heating device 6 is fixed at temperature C11 throughout the entire heating and bonding process. Furthermore, the value of temperature C11 is arbitrarily set based on the performance of the radiant heating device 6, the raw material of the resin film 4 to be heated, etc. Here, the temperature of the radiant heating device 6 is set to 600°C. Additionally, as... Figure 7 As shown in (c), the distance between the radiant heating device 6 and the base 52 is fixed at distance D11 throughout the heating and bonding processes.

[0014] like Figure 7 As shown in (d), the temperature of the resin film 4 increases over time from the starting point t1 when heating begins using the radiant heating device 6. Then, the temperature of the resin film 4 reaches a molding temperature C21 (160°C) at time t2, completing the heating process. The time required for the heating process (from time t1 to time t2) is affected by the output of the radiant heating device 6, the distance of the radiant heating device 6 relative to the base 52, and the raw material of the resin film 4, for example, approximately 8 seconds.

[0015] When the heating process is completed, the thermoforming device 100 performs the bonding process. Specifically, as follows: Figure 7 As shown in (b), vacuum suction is performed using vacuum pump 7 from time point t2 at a maximum exhaust speed S11 corresponding to the capacity of vacuum pump 7. Through this vacuum suction, the resin film 4 is bonded to the pulp molded part 10 while being shaped along its contour. The time required for the bonding process (from time point t2 to time point t6) is affected by the output of the radiant heating device 6, the distance of the radiant heating device 6 relative to the base 52, the thickness of the resin film 4, and the raw materials, etc., and is, for example, approximately 15 seconds.

[0016] Then, along the horizontal direction HZ (e.g., from Figure 6The resin film 4 is fed from left to right in the thermoforming apparatus 100, thereby removing the pulp molded part 10 with the resin film 4 bonded to it from the thermoforming apparatus 100. Then, the thermoforming apparatus 100 bonds the resin film 4 to the next pulp molded part 10. Because the resin film 4 is bonded to the pulp molded parts 4 continuously, multiple pulp molded parts 10 are suspended in a horizontal direction (HZ) on the resin film 4 fed in the horizontal direction. The pulp molded parts 10 are conveyed to the trimming process while suspended on the resin film 4, where the pulp molded parts 10 arranged in a horizontal direction (HZ) are sequentially cut off from the resin film 4.

[0017] [Existing technical documents]

[0018] [Patent Literature]

[0019] [Patent Document 1] Japanese Patent Application Publication No. 2001-233317 Summary of the Invention

[0020] [The problem the invention aims to solve]

[0021] When the resin film 4 is shaped along the form of the pulp molded part 10 in the bonding process after the heating process, such as Figure 8 As shown, an unformed portion 42 is formed around the molded portion 41 of the resin film 4, which is shaped along the shape of the pulp molded part 10. This unformed portion 42 is the remaining part of the resin film 4 before it is shaped. However, the heating performed by the radiant heating device 6 in the heating and bonding processes, and the removal from the thermoforming device 100, may cause slight deformation and changes in the physical properties of the unformed portion 42. As a result, there is a risk that the spacing between the pulp molded parts 10 arranged in the horizontal direction HZ may deviate, which could adversely affect the accuracy of the trimming performed after the resin film 4 is bonded.

[0022] Furthermore, during trimming, it is difficult to precisely cut only the resin film 4. Therefore, the top end of the flange 103 is cut as shown by the cutting line 15, which hypothetically indicates the trimming position, thereby cutting the pulp molded part 10 from the resin film 4. The resin film 4 after cutting off the pulp molded part 10 is rolled up and discarded, but it is difficult to separate because the cut-off top end of the flange 103 remains adhered. If it is difficult to separate, it is difficult to reuse as material, and the environmental burden when discarded is significant.

[0023] The present invention was made in view of the current situation, and its purpose is to provide a thermoforming apparatus that can improve trimming accuracy while reducing environmental impact.

[0024] [Technical means to solve the problem]

[0025] To solve the above problems, the thermoforming apparatus of the present invention has the following configuration.

[0026] (1) A thermoforming apparatus comprising a radiant heating device and a base facing the radiant heating device with a resin film as a barrier, for performing a heating process and a bonding process, wherein the heating process is used to radiantly heat the resin film to a predetermined temperature suitable for molding by means of the radiant heating device, and the bonding process is used to bond the radiantly heated resin film to a fiber molded body placed on the base, characterized in that, before performing the heating process and the bonding process, the resin film, while bonded to the outer periphery of the bonding surface of the resin film on the fiber molded body, is cut into a shape along the outer periphery. The thermoforming apparatus includes: a pressure reduction unit for performing vacuum suction between the fiber molded body and the resin film; and an exhaust speed adjustment unit for adjusting the exhaust speed for performing the vacuum suction of the pressure reduction unit; the exhaust speed adjustment unit adjusts the exhaust speed between a first exhaust speed and a second exhaust speed, the first exhaust speed being used for performing the vacuum suction in the heating process, the second exhaust speed being used for performing the vacuum suction in the bonding process, the second exhaust speed being the exhaust speed for adhering the resin film to the fiber molded body, and the first exhaust speed being slower than the second exhaust speed.

[0027] According to the thermoforming apparatus described in (1), the resin film is characterized in that, before the heating and bonding processes, the resin film is cut into a shape along the outer periphery of the bonding surface of the adhesive resin film bonded to the fiber molded body, so that the resin film is cut before being heated by the radiant heating device. In other words, the resin film can be cut without the resin film undergoing minor deformation or changes in physical properties caused by the heating of the radiant heating device. Therefore, it is possible to improve the trimming accuracy.

[0028] Furthermore, if the trimming precision can be improved, only the resin film can be precisely cut during trimming, avoiding the situation where part of the fiber molded body remains on the resin film after cutting off the fiber molded body. Therefore, the resin film after cutting off the fiber molded body is easy to recycle as a material, and even if recycling as a material is not pursued, the environmental burden at the time of disposal can be reduced.

[0029] (2) In the thermoforming apparatus described in (1), it is preferable to have a control program that controls the output of the radiant heating device to the heating temperature required for the resin film to reach the specified temperature within a specified time, and performs the heating process by means of the decompression unit at the first exhaust speed. After the heating process is completed, the bonding process is performed by means of the decompression unit at the second exhaust speed.

[0030] Before the heating and bonding processes, the resin film is bonded to the outer periphery of the adhesive surface of the fiber molded body, thus trapping air between the fiber molded body and the resin film. Therefore, if the heating process is performed directly, the heating from the radiant heating device will cause the air trapped between the fiber molded body and the resin film to expand, resulting in the resin film bulging towards the radiant heating device. This narrows the distance between the radiant heating device and the resin film, potentially leading to overheating of the resin film and the formation of holes or other defects.

[0031] According to the thermoforming apparatus described in (1) or (2), since it is equipped with a pressure-reducing unit and an exhaust speed adjustment unit, the pressure-reducing unit is used to perform vacuum suction between the fiber molded body and the resin film to make the resin film adhere tightly to the fiber molded body, and the exhaust speed adjustment unit adjusts the exhaust speed used for vacuum suction in the pressure-reducing unit. Therefore, for example, vacuum suction can be performed in the heating process at a first exhaust speed that is slower than the second exhaust speed in the bonding process, thereby preventing the resin film from bulging toward the radiant heating device. Thus, it is possible to prevent the resin film from being overheated. Furthermore, the first exhaust speed is affected by the output of the radiant heating device, the volume of the fiber molded body, etc., and the speed at which the resin film will not bulge toward the radiant heating device can be determined in advance through experiments.

[0032] [The effects of the invention]

[0033] The thermoforming apparatus according to the present invention can improve trimming accuracy while reducing environmental impact. Attached Figure Description

[0034] Figure 1 This diagram illustrates the configuration of the thermoforming apparatus in this embodiment and shows the thermoforming apparatus in the heating process state.

[0035] Figure 2 This diagram illustrates the state of the thermoforming apparatus in the bonding process according to this embodiment.

[0036] Figure 3 This is an enlarged view of the flange (outer periphery) of a pulp molded part (an example of a fiber molded part).

[0037] Figure 4 This is a plan view of the radiant heating device as seen from the heat dissipation section side.

[0038] Figure 5 (a) is a time diagram showing the output of the radiant heating device in the bonding and heating processes. Figure 5 (b) is a time graph showing the exhaust speed of the vacuum pump during the bonding and heating processes. Figure 5(c) is a time diagram showing the location of the radiant heating device in the bonding and heating processes. Figure 5 (d) A chart showing the temperature changes of the resin film during the bonding and heating processes.

[0039] Figure 6 A diagram illustrating the configuration of a prior art thermoforming apparatus.

[0040] Figure 7 (a) is a time diagram related to the output of the radiant heating device in the bonding and heating processes of the prior art. Figure 7 (b) is a time graph showing the relationship between the exhaust speed of the vacuum pump and the bonding and heating processes in the prior art. Figure 7 (c) A timeline showing the location of the radiant heating device in the bonding and heating processes of the prior art. Figure 7 (d) A graph showing the temperature changes of the resin film in the bonding and heating processes of the prior art.

[0041] Figure 8 This is an enlarged view of the flange of a pulp molded part after the resin film has been bonded using a thermoforming device with existing technology. Detailed Implementation

[0042] The thermoforming apparatus of the first embodiment of the present invention will be described with reference to the accompanying drawings. Figure 1 This diagram illustrates the configuration of the thermoforming apparatus 1 in this embodiment and shows the thermoforming apparatus 1 in the heating process state. Figure 2 This diagram illustrates the state of the thermoforming apparatus 1 in the bonding process according to this embodiment. Figure 3 This is an enlarged view of the flange portion 103 (an example of the outer periphery) of the pulp molded part 10 (an example of a fiber molded part). Furthermore, Figure 3 The resin film 4 is the resin film before trimming along the outline of the flange portion 103. Furthermore, Figure 3 The cutting line 14 in the figure is a line that imaginarily indicates the position where the trimming is performed. Figure 4 This is a plan view of the radiant heating device 6 as seen from the heat dissipation section 6a.

[0043] <Regarding the composition of the thermoforming apparatus>

[0044] like Figure 1As shown, the thermoforming apparatus 1 of the first embodiment consists of a lower mold 5 and a radiant heating device 6. It is an apparatus for radiantly heating a resin film 4 to a predetermined temperature suitable for molding using the radiant heating device 6, and then bonding the softened resin film 4 to a pulp molded part 10 (an example of a fiber molded body) placed on the lower mold 5. Furthermore, the process of radiantly heating the resin film 4 to the predetermined temperature suitable for molding using the radiant heating device 6 is called the heating process, and the process of bonding the softened resin film 4 to the pulp molded part 10 placed on the lower mold 5 is called the bonding process.

[0045] The pulp molded part 10 is a food packaging container, for example, formed from pulp material to a thickness of approximately 0.5–3 mm. The shape of the pulp molded part 10 is not particularly limited; for example, it may have a top view (from…) Figure 1 (Viewed from above) The molded pulp 10 consists of an elongated oval bottom 101, a peripheral wall portion 102 rising from the periphery of the bottom 101, and a flange portion 103 extending from the upper end of the peripheral wall portion 102 toward the outside of the pulp molded part 10. Furthermore, the bottom 101 and peripheral wall portion 102 of the pulp molded part 10 are located on the side of the radiant heating device 6. Figure 1 The inner surface (top side) is the bonding surface 104 of the adhesive resin film 4. Furthermore, the pulp material can be wood pulp (virgin material only) or non-wood pulp (virgin material only) such as reeds, sugarcane, or bamboo. However, if the pulp molded part 10 is not used in the food industry, the pulp material can be recycled wood pulp, non-wood pulp, or recycled paper pulp such as newspapers, magazines, or corrugated cardboard, in addition to the materials mentioned above. The pulp molded part 10 is an aggregate of fibers made from the pulp material described above, therefore it is breathable, allowing air to pass through before the adhesive resin film 4 is bonded. Figure 1 It passes between the upper and lower surface sides.

[0046] The resin film 4 is a thermoplastic film made of polypropylene (PP). However, the material is not limited to polypropylene (PP). For example, if the pulp molded part 10 is used in the food industry, it can be used as long as it meets food hygiene standards (such as those stipulated in the Food Hygiene Law). For example, olefin resins such as polyethylene (PE), polyester resins such as polyethylene terephthalate (PET), and ethylene-vinyl acetate copolymers can be used.

[0047] The surface of the resin film 4 facing the pulp molded part 10 is the bonding surface 104 to which it is bonded to the pulp molded part 10, and an adhesive layer (not shown) is provided thereon to improve adhesion to the pulp molded part 10. This adhesive layer is provided by coating a heat-adhesive resin such as a heat sealant or by extruding a heat-adhesive resin.

[0048] Ideally, the thickness of the resin film 4 should be less than 100 μm to reduce manufacturing costs; in this embodiment, a thickness of, for example, 80 μm is used. Furthermore, the accompanying drawings show the resin film 4 as having a thickness approximately half that of the pulp molded part 10, but this is for ease of observation and does not reflect the actual thickness. Additionally, the melting point of the resin film 4 depends on its material and is not particularly limited, but is, for example, 167°C. During the heating process, it is heated to a predetermined temperature suitable for molding. This molding temperature, for example, is 160°C in this embodiment (temperature C21 (reference)). Figure 5 (d)).

[0049] Furthermore, before the resin film 4 is shaped by the thermoforming apparatus 1, it is viewed from the top of the pulp molded part 10 (from...). Figure 1 The shape (as seen from above) has been pre-cut. Specifically, as... Figure 1 As shown, the resin film 4 is pre-cut along the outer periphery of the flange portion 103, for example, using a trimming device, while only bonded to the flange portion 103. In other words, the resin film 4 is cut before being heated by the radiant heating device 6, allowing the resin film 4 to be cut without experiencing the minor deformation or changes in its properties caused by the heating of the radiant heating device 6. Therefore, it is possible to improve the trimming accuracy.

[0050] Furthermore, if the trimming precision can be improved, it will be possible to cut only the resin film 4 with high accuracy during trimming. Specifically, it has been difficult to cut only the resin film 4 with high precision in the past, so it is like... Figure 8 As shown by the cutting line 15, the tip of the flange portion 103 is trimmed. However, the thermoforming apparatus 1 of this embodiment can improve the trimming accuracy, thus enabling it to achieve the following: Figure 3 As shown by the cutting line 14, the resin film 4 is precisely cut only at the boundary between the portion of the resin film 4 bonded to the flange 103 and the surrounding unbonded portion of the resin film 4. Therefore, there will be no residue of the pulp molded part on the resin film after the fiber molded body (pulp molded part 10) is cut off. Therefore, the resin film after the fiber molded body (pulp molded part 10) is cut off can be easily recycled as a material, and even if recycling as a material is not pursued, the environmental burden at the time of disposal can be reduced.

[0051] Furthermore, the bonding and cutting of the resin film 4 only on the flange portion 103 can be performed by a device other than the thermoforming device 1 in the form of a pre-process, or the resin film 4 can be bonded only to the flange portion 103 by the thermoforming device 1 equipped with a cutting device such as a Thomson blade, and then cut along the outer periphery of the flange portion 103 by means of the cutting device.

[0052] The resin film 4 described above is heated to approximately 160°C by the radiant heating device 6 within the thermoforming apparatus 1, and then... Figure 2 As shown, the pulp molded part 10 is shaped along the bonding surface 104 and bonded to the bonding surface 104. The pulp molded part 10 acquires water resistance, oil resistance, and heat resistance through the bonding of the resin film 4.

[0053] The lower mold 5 consists of a mold box 51, a base 53, and a platform 52. The mold box 51 is made of metal components such as stainless steel and has a frame 512 and a peripheral wall 511 erected on the frame 512. The frame 512 has a vent 512a extending vertically VT, and a vacuum pump 7 (an example of a pressure reducing unit) is connected to the vent 512a. The vacuum pump 7 can perform vacuum suction inside the mold box 51 through the vent 512a.

[0054] A base 53, surrounded by a peripheral wall 511, is fixed above the frame 512 for mounting the base 52. The base 53 has multiple connecting channels 531 that extend through the base 53 in the vertical direction VT. The base 52, surrounded by a peripheral wall 511, is mounted on the upper end face of the base 53 in the vertical direction VT for placing the pulp molded part 10.

[0055] The base 52 has a mounting surface 521, identical in shape to the pulp molding part 10, passing through its end face on the side of the radiant heating device 6 (the upper side in the vertical direction VT). Furthermore, the base 52 has multiple vacuum vents 522 formed on the mounting surface 521. When a vacuum is applied to the mold box 51 using the vacuum pump 7, vacuum suction can be applied to the mounting surface 521 side via the connecting channel 531 and the vacuum vents 522. The pulp molding part 10 is permeable, so even if the pulp molding part 10 is mounted on the mounting surface 521, it will not hinder vacuum suction on the mounting surface 521 side. Therefore, by… Figure 1 Vacuum attraction is performed on the mounting surface 521 side in the state shown, so that vacuum attraction can be performed between the pulp molding part 10 and the resin film 4, thereby bonding the resin film 4 to the bonding surface 104 of the pulp molding part 10 without gaps.

[0056] A vacuum pump 7 is connected to the vent 512a of the lower mold 5 by parallel first pipe 11A and second pipe 11B.

[0057] A first on / off valve 8 is provided on the first pipe 11A. If the first on / off valve 8 is opened, the first pipe 11A is open, 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 cut off.

[0058] Starting from the vacuum pump 7 side, a second on / off valve 9 and a flow regulating valve 13 are sequentially installed on the second pipe 11B. When the second on / off valve 9 is opened, the second pipe 11B is open, allowing the vacuum pump 7 to perform vacuum suction via the second pipe 11B. Conversely, when the second on / off valve 9 is closed, the second pipe 11B is cut off. Furthermore, the flow regulating valve 13 can adjust the valve opening, thereby adjusting the exhaust speed during vacuum suction via the second pipe 11B.

[0059] Vacuum pump 7 operates continuously during the operation of thermoforming apparatus 1. If the first on / off valve 8 is opened and the second on / off valve 9 is closed, the maximum exhaust speed S11 (reference) corresponding to the capacity of vacuum pump 7 can be achieved via the first pipe 11A. Figure 5 (b) (An example of the second exhaust speed)) Vacuum suction is performed. On the other hand, if the first on / off valve 8 is closed and the second on / off valve 9 is opened, an exhaust speed corresponding to the valve opening of the flow regulating valve 13 (e.g., the specified exhaust speed S12 described later) can be achieved via the second pipe 11B. Figure 5 (b) (An example of the first exhaust speed))) Vacuum suction is performed. That is, the first pipe 11A, the second pipe 11B, the first on / off valve 8, the second on / off valve 9, and the flow regulating valve 13 function as an exhaust speed regulating unit to adjust the exhaust speed of the vacuum pump 7.

[0060] The radiant heating device 6 is positioned facing the lower mold 5 through the resin film 4. In the radiant heating device 6, the end face of the lower mold 5 is a heat dissipation part 6a, as shown below. Figure 4 As shown, the heat dissipation section 6a is formed by a plurality of heater elements 61. Specifically, the radiant heating device 6 has a total of 30 heater elements 61, arranged in five rows along the Y direction, with six heater elements 61 (octagonal in top view) arranged adjacently along the X direction. These 30 heater elements 61 constitute the heat dissipation section 6a. Furthermore, Figure 4 The so-called X direction in the text is related to... Figure 1 and Figure 2 The horizontal direction HZ is parallel to the direction mentioned above. Furthermore, the number of heater elements 61 is just one example and is not limited to the number mentioned above.

[0061] In addition, such as Figure 4 As shown, a temperature sensor 62 is provided on the radiant heating device 6, surrounded by four heater elements 61 located in the central region of the radiant heating device 6. The temperature sensor 62 is, for example, a radiation thermometer. This temperature sensor 62 is capable of measuring the temperature of the surface of the resin film 4 facing the radiant heating device 6. Thus, the thermoforming apparatus 1 can detect the temperature of the resin film 4 during the heating and bonding processes.

[0062] The radiant heating device 6 can move up and down in the vertical direction VT by means of the lifting unit 12 (e.g., cylinder), so that it can move between the first heating position and the second heating position. Figure 1 The position of the radiant heating device 6 shown is the first heating position used for radiant heating of the resin film 4 in the heating process. Figure 2 The position of the radiant heating device 6 shown is the second heating position for radiant heating of the resin film 4 during the bonding process. Furthermore, the distance D12 between the radiant heating device 6 at the second heating position and the base 52 is set smaller than the distance D11 between the radiant heating device 6 at the first heating position and the base 52. Thus, by moving the radiant heating device 6 between the first and second heating positions, the distance between the radiant heating device 6 and the resin film 4 can be changed. Moreover, the distances D11 between the radiant heating device 6 at the first heating position and the base 52, and D12 between the radiant heating device 6 at the second heating position and the base 52 are determined based on the output of the radiant heating device 6, the raw material of the resin film 4, and the target time required for the heating and bonding processes.

[0063] <Regarding the heating and bonding processes>

[0064] use Figure 5 The heating and bonding processes performed using the thermoforming apparatus 1 with the above configuration will be described. Figure 5 (a) is a time diagram of the output of the radiant heating device 6 in the bonding and heating processes. Figure 5 (b) is a time graph showing the exhaust speed of vacuum pump 7 in the bonding and heating processes. Figure 5 (c) is a time diagram related to the position of the radiant heating device 6 (distance of the radiant heating device 6 relative to the base 52) in the bonding and heating processes. Figure 5 (d) is a graph showing the temperature changes of the resin film 4 during the bonding and heating processes.

[0065] Before starting the heating and bonding processes, the resin film 4 is positioned so that it is only bonded to the flange 103 of the pulp molded part 10, and the resin film 4 is cut along the top view of the pulp molded part 10. Then, as... Figure 1 As shown, the pulp molded part 10 is placed on the mounting surface 521 of the base 52. Furthermore, the operation of placing the pulp molded part 10 on the mounting surface 521 can be performed manually by an operator or by an automatic conveying device or the like.

[0066] Furthermore, before starting the heating and bonding processes, the vacuum pump 7 is operated with the first on / off valve 8 and the second on / off valve 9 closed, thus cutting off the first pipe 11A and the second pipe 11B. This ensures that a predetermined exhaust speed S12 is achieved when the second on / off valve 9 is opened (see reference). Figure 5 (b) Adjust the valve opening of the flow regulating valve 13 in the manner described. Furthermore, the details of the specified exhaust speed S12 will be described later.

[0067] First, the heating process will be explained. For example... Figure 5 As shown in (a), the heating process begins at time point t1, starting with the output of the radiant heating device 6. The output of the radiant heating device 6 is fixed at temperature C11 throughout the entire heating and bonding process. Furthermore, the value of temperature C11 is arbitrarily set based on the performance of the radiant heating device 6 and the raw material of the resin film 4 being heated, and is not particularly limited. In this embodiment, it is set to the maximum output of the radiant heating device 6, i.e., 600°C. Additionally, as... Figure 5 As shown in (c), the distance between the radiant heating device 6 and the base 52 is distance D11. This indicates that the radiant heating device 6 is in the first heating position.

[0068] Regarding the vacuum suction using vacuum pump 7, such as Figure 5 As shown in (b), vacuum suction begins at a predetermined exhaust rate S12 starting from time point t1. This vacuum suction is performed by keeping the first on / off valve 8 closed and opening the second on / off valve 9 to open the second pipe 11B.

[0069] Since the resin film 4 is already bonded to the flange 103 of the pulp molding part 10, air is trapped between the pulp molding part 10 and the resin film 4. Therefore, if heating is performed directly by the radiant heating device 6, the air trapped between the pulp molding part 10 and the resin film 4 will expand, causing the resin film 4 to tilt towards the radiant heating device 6. Figure 1 The resin film 4 bulges upwards (at the top). As a result, the distance between the radiant heating device 6 and the resin film 4 narrows, and the resin film 4 is overheated, potentially leading to defects such as voids. Therefore, as described above, vacuum suction at a predetermined exhaust speed S12 is used to prevent the resin film 4 from bulging towards the radiant heating device 6, thereby preventing overheating of the resin film 4.

[0070] The specified exhaust speed S12 is affected by factors such as the output of the radiant heating device 6 and the volume of the pulp molding part 10. The speed at which the resin film 4 will not bulge towards the radiant heating device 6 is determined experimentally in advance. Furthermore, the opening of the flow regulating valve 13 is adjusted based on the specified exhaust speed S12 determined experimentally. Ideally, the resin film 4 should be kept as horizontal as possible by vacuum suction at the specified exhaust speed S12. The aim is to heat the entire resin film 4 uniformly. However, it is not necessary to keep it horizontal; it is sufficient as long as the resin film 4 does not bulge towards the radiant heating device 6. For example, vacuum suction at the specified exhaust speed S12 can also cause the resin film 4 to deform concavely towards the pulp molding part 10 to a degree that does not require shaping. Furthermore, the vacuum suction at the specified exhaust speed S12 is performed from time point t1 at the start of the heating process, but it does not necessarily have to be simultaneous. For example, the moment when the air between the pulp molded part 10 and the resin film 4 begins to expand after heating can be determined in advance through experiments, and vacuum suction at a specified exhaust speed S12 can be performed according to that moment.

[0071] Return to Figure 5 The explanation, such as Figure 5 As shown in (d), the temperature of the resin film 4 increases proportionally with time from the time point t1 when heating begins using the radiant heating device 6. Furthermore, the temperature of the resin film 4 reaches a molding temperature C21 (160°C) at time point t2, and the heating process is completed. The time required for the heating process (from time point t1 to time point t2) is affected by the output of the radiant heating device 6, the distance of the radiant heating device 6 relative to the base 52, the raw material of the resin film 4, etc., and is approximately 8 seconds in this embodiment.

[0072] Next, the bonding process will be explained. When the heating process is complete, as follows... Figure 5 (b) shows that vacuum suction is performed using vacuum pump 7 at the maximum exhaust speed S11. This vacuum suction is achieved by closing the second on / off valve 9 to cut 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 membrane 4... Figure 2 It is shaped along the shape of the pulp molded part 10 as shown.

[0073] Furthermore, at time point t2, the distance image of the radiant heating device 6 relative to the base 52 is... Figure 5 (c) shows a change in direction towards distance D12. This indicates that the radiant heating device 6 is in the second heating position. At this time, as shown... Figure 5 As shown in (a), the output of the radiant heating device 6 is in a fixed state.

[0074] Because the resin film 4 is shaped and comes into contact with the pulp molding part 10, the temperature of the resin film 4 is cooled by the pulp molding part 10, so like Figure 5 As shown in (d), the temperature drops to C22. However, the radiant heating device 6 continues to heat the resin film 4 at the second heating position, so the temperature of the resin film 4 recovers to temperature C21 at time t3.

[0075] The distance between the radiant heating device 6 at the second heating position and the resin film 4 is closer than that at the first heating position, thus increasing the heat supplied to the resin film 4 by the radiant heating device 6. Therefore, the time required for the resin film 4, which has cooled down due to contact with the pulp molded part 10, to reach temperature C21 again through radiant heating (the time from time point t2 to time point t3) is shorter than the time previously required. Figure 7 (d) The time from time point t2 to time point t5 is shorter. Specifically, it is about 20-60% shorter than the time required in the past.

[0076] Furthermore, the heat supplied to the resin film 4 by the radiant heating device 6 can be increased when bonding the resin film 4 to the pulp molding part 10. Therefore, the amount of temperature drop of the resin film 4 caused by contact with the pulp molding part 10 (the amount of temperature drop from temperature C21 to temperature C22) can be suppressed. Specifically, compared with the conventional temperature drop ( Figure 7 Compared to the decrease in temperature from C21 to C22 in (d), the decrease becomes about 20-60%. As a result, the temperature difference between the part of the resin film 4 that has contacted the pulp molded part 10 and the part that has not contacted the fiber molded body can be mitigated, thereby enabling stable bonding of the resin film 4 to the pulp molded part 10.

[0077] Return to Figure 5 As explained, from the start of the bonding process until time point t4, heating using the radiant heating device 6 and vacuum suction using the vacuum pump 7 continue. The purpose is to more reliably bond and adhere the resin film 4 to the pulp molded part 10.

[0078] At time t4, the radiation heating device 6 images Figure 5 The output stops as shown in (a). Simultaneously, the radiant heating device 6... Figure 5 (c) Returns to the first heating position as shown. Alternatively, it is not necessary to return to the first heating position; it can be moved to a position further away from the base 52 than the first heating position. Then, at time t4, the first on / off valve 8 is closed, cutting off the first pipe 11A, thereby... Figure 5 (b) shows that the vacuum suction stops. The bonding process is now complete. The time required for the bonding process (from time point t2 to time point t4) is affected by the output of the radiant heating device 6, the distance between the radiant heating device 6 and the base 52, the thickness of the resin film 4, and the density (air permeability) of the raw materials and the pulp molded part 10, etc. In this embodiment, it is about 6 to 10 seconds.

[0079] As described above, the time required for the resin film 4, which has cooled down due to contact with the pulp molded part 10, to reach temperature C21 again through radiant heating (the time from time point t2 to time point t3) is longer than the time previously required. Figure 7 (d) The time from time point t2 to time point t5 is shorter, so the time required for the bonding process (from time point t2 to time point t4) is shorter than the time required for the previous bonding process. Figure 7 The time from time point t2 to time point t6 is shortened by about 20-60%, in order to improve manufacturing efficiency.

[0080] After the bonding process is completed, the pulp molded part 10 with the bonded resin film 4 is removed from the base 52. This removal of the pulp molded part 10 with the bonded resin film 4 can be performed manually by an operator or by an automatic conveying device.

[0081] The heating and bonding processes described above are performed automatically by a control program stored in a control device (not shown) connected to the thermoforming apparatus 1.

[0082] <Second Embodiment>

[0083] The differences between the thermoforming apparatus of the second embodiment and the thermoforming apparatus 1 of the first embodiment will be described only for the thermoforming apparatus of the second embodiment.

[0084] The thermoforming apparatus of the second embodiment has the same Figure 1 The thermoforming apparatus 1 shown in the first embodiment has the same configuration, but the second heating position of the radiant heating device 6 is different. Figure 1 In the second heating position of the thermoforming apparatus 1 shown in the first embodiment, the distance between the radiant heating device 6 and the base 52 at the second heating position of the thermoforming apparatus in the second embodiment is set farther than that at the first heating position. That is, the radiant heating device 6 moves away from the resin film 4 during the transition from the heating process to the bonding process.

[0085] During the bonding process, when the radiant heating device 6 radiates heat to the resin film 4, the pulp molded part 10 may be overheated and scorched due to its different material. Therefore, by moving the radiant heating device 6 away from the resin film 4 during the bonding process, the heat supplied to the pulp molded part 10 by the radiant heating device 6 can be reduced. This prevents the pulp molded part 10 from being overheated.

[0086] As explained above, according to the thermoforming apparatus 1 of this embodiment, (1) a thermoforming apparatus 1, which includes a radiation heating device 6 and a base 52 facing the radiation heating device 6 with a resin film 4 in between, for performing a heating process and a bonding process, wherein the heating process is used to radiate heat the resin film 4 to a predetermined temperature C21 that can be formed by means of the radiation heating device 6, and the bonding process is used to bond the radiated heated resin film 4 to a fiber molded body (pulp molded part 10) placed on the base 52. The thermoforming apparatus 1 is characterized in that, before performing the heating process and the bonding process, the resin film 4 is cut into a shape along the outer periphery (flange portion 103) of the bonding surface 104 of the bonding resin film 4 bonded to the fiber molded body (pulp molded part 10) in a state where it is bonded to the fiber molded body (pulp molded part 10).

[0087] According to the thermoforming apparatus 1 described in (1), the resin film 4 is characterized in that, before the heating and bonding processes, the resin film 4 is cut into a shape along the outer periphery (flange 103) of the bonding surface 104 of the adhesive resin film 4 bonded to the fiber molding body (pulp molding part 10). Therefore, the resin film 4 is cut before being heated by the radiant heating device 6. In other words, the resin film 4 can be cut without the slight deformation or change in physical properties caused by the heating of the radiant heating device 6. Therefore, it is possible to improve the trimming accuracy.

[0088] Furthermore, if the trimming precision can be improved, only the resin film 4 can be cut with high accuracy during trimming, and there will be no residue of the pulp molded part on the resin film after the fiber molded body (pulp molded part 10) is cut off. Therefore, the resin film after the fiber molded body (pulp molded part 10) is cut off can be easily recycled as a material, and even if recycling as a material is not pursued, the environmental burden at the time of disposal can be reduced.

[0089] (2) In the thermoforming apparatus 1 described in (1), it is characterized by having a pressure reducing unit (vacuum pump 7) and an exhaust speed adjustment unit (first pipe 11A, second pipe 11B, first on / off valve 8, second on / off valve 9, flow adjustment valve 13), wherein the pressure reducing unit (vacuum pump 7) is used to perform vacuum suction between the fiber molded body (pulp molded part 10) and the resin film 4, and the exhaust speed adjustment unit (first pipe 11A, second pipe 11B, first on / off valve 8, second on / off valve 9, flow adjustment valve 13) adjusts the exhaust speed used for vacuum suction by the pressure reducing unit (vacuum pump 7).

[0090] (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 adjustment valve 13) adjusts the exhaust speed between a first exhaust speed (prescribed exhaust speed S12) and a second exhaust speed (maximum exhaust speed S11). The first exhaust speed (prescribed exhaust speed S12) is used for vacuum suction in the heating process, and the second exhaust speed (maximum exhaust speed S11) is used for vacuum suction in the bonding process. The second exhaust speed (maximum exhaust speed S11) is the exhaust speed used to tightly bond the resin film 4 to the fiber molded body (pulp molded part 10). The first exhaust speed (prescribed exhaust speed S12) is slower than the second exhaust speed (maximum exhaust speed S11).

[0091] (4) In the thermoforming apparatus 1 described in (3), the feature is that it has a control program that controls the output of the radiation heating device 6 to the heating temperature (temperature C11) required for the resin film 4 to reach the specified temperature C21 within a specified time (from time point t1 to time point t2), and simultaneously performs a vacuum suction at a first exhaust speed (specified exhaust speed S12) by means of a decompression unit (vacuum pump 7) to perform a heating process, and after the heating process is completed, performs a vacuum suction at a second exhaust speed (maximum exhaust speed S11) by means of a decompression unit (vacuum pump 7) to perform a bonding process.

[0092] Before the heating and bonding processes, the resin film 4 is bonded to the outer periphery (flange 103) of the bonding surface 104 of the adhesive resin film 4 on the fiber molding body (pulp molding part 10), thus trapping air between the fiber molding body (pulp molding part 10) and the resin film 4. Therefore, if the heating process is performed directly, the heating from the radiant heating device 6 will cause the air trapped between the fiber molding body (pulp molding part 10) and the resin film 4 to expand, causing the resin film 4 to bulge towards the radiant heating device 6. Consequently, the distance between the radiant heating device 6 and the resin film 4 narrows, potentially leading to overheating of the resin film 4 and the appearance of defects such as holes.

[0093] According to the thermoforming apparatus 1 described in (2), (3), or (4), since it is equipped with a pressure reducing unit (vacuum pump 7) and an exhaust speed adjustment unit (first pipe 11A, second pipe 11B, first on / off valve 8, second on / off valve 9, flow adjustment valve 13), the pressure reducing unit (vacuum pump 7) is used to perform vacuum suction between the fiber molded body (pulp molded part 10) and the resin film 4 to make the resin film 4 tightly bonded to the fiber molded body (pulp molded part 10). The exhaust speed adjustment unit (first pipe 11A, second pipe 11B, first on / off valve 8, second on / off valve 9, flow adjustment valve 13) adjusts the exhaust speed used for vacuum suction by the pressure reducing unit (vacuum pump 7). Therefore, for example, vacuum suction can be performed in the heating process at a first exhaust speed (specified exhaust speed S12) that is slower than the second exhaust speed (maximum exhaust speed S11) in the bonding process, thereby preventing the resin film 4 from bulging toward the radiant heating device 6. As a result, it is possible to prevent the resin film 4 from being overheated.

[0094] Furthermore, this embodiment is merely an example and does not limit the invention in any way. Therefore, the invention can naturally be modified and varied in various ways without departing from its spirit. For example, the thermoforming apparatus 1 uses a single pulp molded part 10 placed on the base 52 for bonding the resin film 4, but multiple pulp molded parts can also be bonded simultaneously. Furthermore, in the thermoforming apparatus 1, the radiant heating device 6 is located above the lower mold 5, but the vertical position can be reversed. Additionally, the resin film 4 is described as having an adhesive layer, but a resin film without an adhesive layer can also be used.

[0095] Symbol Explanation

[0096] 1…Thermoforming apparatus

[0097] 4…Resin film

[0098] 6…Radiant heating device

[0099] 10… Pulp molded parts (an example of fiber-molded parts)

[0100] 104… Adhesive surface

[0101] 103…Flange (an example of the outer periphery).

Claims

1. A thermoforming apparatus comprising a radiant heating device and a base facing the radiant heating device across a resin film, for performing a heating process and a bonding process, wherein the heating process is used to radiantly heat the resin film to a predetermined temperature suitable for molding using the radiant heating device, and the bonding process is used to bond the radiantly heated resin film to a fiber molded body placed on the base, characterized in that... Before the heating and bonding processes, the resin film, while bonded to the outer periphery of the bonding surface of the fiber molded body, is cut into a shape following the outer periphery. This thermoforming apparatus has the following features: A pressure-reducing unit is used to perform vacuum suction between the fiber molded body and the resin film; and An exhaust speed adjustment unit adjusts the exhaust speed used for vacuum suction in the pressure reduction unit; The exhaust speed adjustment unit adjusts the exhaust speed between a first exhaust speed and a second exhaust speed. The first exhaust speed is used for vacuum suction in the heating process, and the second exhaust speed is used for vacuum suction in the bonding process. The second exhaust speed is the exhaust speed used to ensure close contact between the resin film and the fiber molded body. The first exhaust speed is slower than the second exhaust speed.

2. The thermoforming apparatus according to claim 1, characterized in that, The device includes a control program that controls the output of the radiant heating device to the heating temperature required for the resin film to reach the specified temperature within a specified time. Simultaneously, the vacuum suction is performed at the first exhaust velocity using the decompression unit, thereby carrying out the heating process. After the heating process is completed, the vacuum suction is performed at the second exhaust speed by means of the decompression unit, thereby performing the bonding process.

Images