Drying systems, venting systems and manufacturing systems

Abstract

A manufacturing system according to the present invention includes a drying system, a vent system, and an injection molding machine. The drying system includes a dehumidifier, a heater for heating dehumidified gas, a drying tank that stores a resin material and into which heated drying gas is blown, a catalyst tank for decomposing impurities contained in exhaust gas, and a cooler that cools the gas and sends the gas to the dehumidifier. The vent system includes: a melting part in which the resin material is heated and melted, the melting part having a vent port; a pump for reducing the pressure at the vent port; and a catalyst tank provided between the pump and the vent port to decompose impurities.

Description

[Technical field]

[0001] The present invention relates to drying systems, vent systems and manufacturing systems. [Background technology]

[0002] Resin containers, such as polyethylene terephthalate (PET) containers known as PET bottles, are widely used. Recycling of such resin containers is carried out by collecting used containers and reusing them as materials to manufacture containers. When using recycled resin materials as materials, it is necessary to remove contaminants contained in the recycled materials. In mechanical recycling, collected used containers are sorted, crushed, and washed to remove dirt and foreign matter from the surface, and then contaminants remaining inside the resin are exposed to high temperatures to be decontaminated.

[0003] For example, Japanese Patent Publication No. 2019-514728 (International Publication No. 2017 / 183048) discloses a preform manufacturing apparatus that removes contaminants in resin flakes using a decontamination machine, supplies the decontaminated resin material to an injection molding machine connected to the decontamination machine, and manufactures preforms using the injection molding machine.

[0004] For example, when PET is reused as recycled material (regenerated PET) by mechanical recycling, a part of the PET is depolymerized or thermally decomposed by decontamination treatment at high temperatures, generating sublimable or volatile low molecular weight components such as monohydroxyethyl terephthalate (MHET), bishydroxyethyl terephthalate (BHET), cyclic trimer (CT), acetaldehyde, etc. If such low molecular weight components are contained in large amounts in the recycled material or are attached to the recycled material and supplied to injection molding, etc., problems such as contamination of the injection molding die and peripheral equipment and reduced productivity of the product can occur. Summary of the Invention

[0005] It is preferable that impurities contained in the resin material, such as the above-mentioned low molecular weight components contained in the recycled material, are removed before use.

[0006] An object of the present invention is to remove impurities contained in a resin material.

[0007] According to one aspect of the present invention, a drying system for drying a resin material using a circulating gas includes a dehumidifier configured to dehumidify a gas to obtain a dehumidified gas, a heater configured to heat the dehumidified gas to obtain a dry gas, a drying tank configured to accommodate the resin material and to blow in the dry gas, a catalyst tank configured to circulate exhaust gas from the drying tank and containing a catalyst for decomposing low molecular weight impurities derived from the resin material contained in the exhaust gas, and a cooler configured to cool the gas that has passed through the catalyst tank to obtain a cooling gas. The cooling gas is configured to be sent to the dehumidifier for the dehumidification.

[0008] According to one aspect of the present invention, a vent system for removing impurities from a molten resin material includes a melting section having a vent port configured to heat and melt the resin material, a pump configured to reduce pressure at the vent port, and a catalyst tank provided in a flow path between the pump and the vent port, the catalyst tank containing a catalyst for decomposing low molecular weight impurities derived from the molten resin material that are generated as a gas from the resin material.

[0009] According to one aspect of the present invention, a manufacturing system includes the above-mentioned drying system, the above-mentioned vent system configured to use the resin material dried by the drying system, and an injection molding machine that performs injection molding using the molten resin material.

[0010] According to the present invention, impurities contained in a resin material can be removed. [Brief description of the drawings]

[0011] [Figure 1]FIG. 1 is a diagram illustrating an outline of a configuration example of a manufacturing system according to an embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] An embodiment will be described with reference to the drawings. This embodiment relates to a manufacturing system used for manufacturing resin products. An example of a finished resin product is a container made of polyethylene terephthalate (PET), known as a PET bottle. As an example of a method for manufacturing such a container, a method of biaxially stretching and blow molding a resin preform is known. This embodiment relates to a manufacturing system equipped with an injection molding machine for molding a preform for manufacturing a PET bottle. The manufacturing system of this embodiment is configured to efficiently remove impurities contained in a resin material. For example, a recycled material of PET by mechanical recycling may contain a large amount of impurities such as low molecular weight components compared to a virgin material. For this reason, this manufacturing system is a suitable system especially when a PET recycled material is used.

[0013] [Manufacturing system configuration overview] FIG. 1 is a diagram showing a schematic overview of a configuration example of a manufacturing system 1 according to the present embodiment. The manufacturing system 1 includes an injection molding machine 10, a drying system 20, and a vent system 30. The drying system 20 circulates high-temperature air (dry circulating gas) to remove moisture, impurities, and the like contained in the flake-shaped or pellet-shaped resin material, which is the material to be fed into the injection molding machine 10. In particular, low-molecular-weight components attached to or adsorbed on the surface of the resin material can be removed as impurities. The resin material dried and decontaminated by the drying system 20 is supplied to the injection molding machine 10. The injection molding machine 10 molds a preform by injection molding. The vent system 30 is a system that removes impurities from the molten resin material using a vent port at the melting unit site that melts the resin material in the injection molding machine 10. In particular, low-molecular-weight components trapped in the resin material can also be removed as impurities.

[0014] [Injection molding machine configuration] Injection molding machine 10 includes a melting unit 120, an injection unit 130, and a mold 140.

[0015] The melting unit 120 has a cylindrical cylinder 121 and a screw 122 inserted into the cylinder 121. A heater (not shown) is provided in the cylinder 121. The resin material in the form of flakes or pellets is stored in a drying tank 211 called a hopper. The resin material in the drying tank 211 is stored in a dried state by the operation of a drying system 20, which will be described later.

[0016] The resin material is supplied from the drying tank 211 into the cylinder 121 of the melting unit 120. The melting unit 120 heats and melts the supplied resin material with heat from a heater, and kneads the resin material by rotating the screw 122. In this manner, the melting unit 120 functions as a melting section configured to heat and melt the resin material. The temperature inside the cylinder 121 is, for example, approximately 300°C. The screw 122 stirs and melts the resin material in the cylinder 121, makes the temperature uniform, and sends the molten resin material to the injection unit 130. The cylinder 121 is provided with a vent port 123 between the resin material supply section and the resin supply section to the injection unit 130, as will be described in detail later.

[0017] The injection unit 130 injects a predetermined amount of molten resin material into the clamped mold 140. The molten resin injected into the mold 140 is cooled and solidified, completing the molding of the preform. The mold 140 is opened, and the molded preform is removed.

[0018] [Drying system configuration] The drying system 20 includes a drying tank 211 connected to the above-mentioned injection molding machine 10. The drying tank 211 contains a flake-shaped or pellet-shaped resin material. In this embodiment, in particular, a resin material containing a recycled material is used. The recycled material is prepared by crushing and cleaning used resin containers. The PET recycled material is mainly composed of PET, but may contain moisture and low molecular weight impurities derived from the resin material.

[0019] Heated dry circulating gas is blown into the drying tank 211. The temperature of the dry circulating gas is, for example, about 130-200° C., for example, about 160° C. The temperature of the resin material that comes into contact with the high-temperature dry circulating gas in the drying tank 211 increases, and moisture and impurities contained in the resin material or attached or adsorbed to the surface of the resin material move into the dry circulating gas.

[0020] The dry circulation gas containing moisture, impurities, etc. is discharged from the drying tank 211. The exhaust gas is dehumidified and heated, and is reused as the dry circulation gas. For this reason, the drying system 20 includes a first heater 213, a first catalyst tank 215, a first filter 217, a first heat exchanger 219, a first blower 221, an adsorption tower 223, and a drying heater 225, which are provided in this order in the flow path of the exhaust gas (gas). The blower for circulating the gas is not limited to the first blower 221, and other blowers may be appropriately added to the flow path. The amount of gas flowing through this flow path is adjusted by a first valve 251, which is a control valve.

[0021] Drying system 20 also includes a nitrogen enrichment membrane 233 for additionally supplying nitrogen gas to this flow path. The outlet of nitrogen enrichment membrane 233 is connected downstream of first heat exchanger 219. The amount of nitrogen gas supplied to the above-mentioned flow path is adjusted by a second valve 252, which is a control valve.

[0022] The exhaust gas from the drying tank 211 is heated and kept warm by the first heater 213. The first heater 213 maintains the temperature of the exhaust gas at approximately the same temperature as the temperature of the drying gas in the drying tank 211, for example, at approximately 130-200°C, for example, at approximately 160°C. In this way, liquefaction (condensation) or solidification of impurities due to a drop in the temperature of the exhaust gas is prevented, and contamination of the pipelines and the like is suppressed. Instead of arranging the first heater 213, a heat-insulating material may be provided in the exhaust flow path to keep the exhaust gas warm.

[0023] The exhaust gas is sent to a first catalyst tank 215. The first catalyst tank 215 contains, for example, an active metal Pt / Pd catalyst. The first catalyst tank 215 is provided with a heater 216, and the first catalyst tank 215 is heated to 150-550°C, more preferably 200-300°C, so as to promote an oxidation-reduction reaction. In the first catalyst tank 215, impurities contained in the exhaust gas are oxidized and decomposed by catalytic action, and at the same time, oxygen in the dry circulation gas is consumed.

[0024] The exhaust gas that has passed through the first catalyst tank 215 is sent to a first heat exchanger 219 via a first filter 217. The first heat exchanger 219 cools the gas. The cooled gas is sent to an adsorption tower 223 by a first blower 221. The first heat exchanger 219 is provided with a drain valve 258 for discharging condensed liquid.

[0025] The adsorption tower 223 adsorbs moisture contained in the cooled gas and dehumidifies it. By sufficiently cooling the gas in the first heat exchanger 219 before introducing it into the adsorption tower 223, a sufficiently dehumidified gas is obtained in the adsorption tower 223. The gas dehumidified in the adsorption tower 223 is sent to the drying heater 225.

[0026] The dry heater 225 heats the dehumidified exhaust gas for use as a dry circulating gas. The dry circulating gas heated by the dry heater 225 is circulated and supplied again to the drying tank 211 as described above.

[0027] Drying system 20 includes a second blower 235 and a regeneration heater 237 for regenerating adsorption tower 223. Drying system 20 also includes a third valve 253, a fourth valve 254, a fifth valve 255, and a sixth valve 256 for switching the flow path between a drying process for supplying a dry circulating gas to drying tank 211 and a regeneration process for regenerating adsorption tower 223.

[0028] The third valve 253 is provided between the first blower 221 and the adsorption tower 223, and the fourth valve 254 is provided between the adsorption tower 223 and the drying heater 225. A branch path is provided between the third valve 253 and the adsorption tower 223, and a fifth valve 255 is provided therein. The second blower 235 and the regeneration heater 237 are connected to the adsorption tower 223 via the fifth valve 255. A branch path is provided between the adsorption tower 223 and the fourth valve 254, and one end of a sixth valve 256 is connected thereto. The other end of the sixth valve 256 is open to the outside.

[0029] In the drying process in which the dry circulating gas is supplied to the drying tank 211, the third valve 253 and the fourth valve 254 are opened to open the circulation flow path, while the fifth valve 255 and the sixth valve 256 are closed.

[0030] In contrast, in the adsorption tower drying / dehumidification process for regenerating the adsorption tower 223, the third valve 253 and the fourth valve 254 are closed and the above-mentioned circulation flow path is blocked. Meanwhile, the fifth valve 255 and the sixth valve 256 are opened. At this time, the outside air taken in by the second blower 235 is heated by the regeneration heater 237, and the heated gas is sent to the adsorption tower 223 via the fifth valve 255. The moisture adsorbed in the adsorption tower 223 is taken away by the gas heated by the regeneration heater, and the gas containing moisture is discharged to the outside air from the open end of the sixth valve 256. The adsorption tower 223 is provided with a drain valve 259 for discharging liquid.

[0031] [Drying system function] According to the drying system 20, for example, moisture and impurities in the resin material contained in the recycled PET material are removed by the high-temperature dry circulation gas passing through the drying tank 211. In particular, low-molecular-weight impurities attached or adsorbed on the surface of the resin material and vaporized at the temperature of the dry circulation gas (for example, about 130-200°C) can be removed. In addition to water, low-molecular-weight impurities such as acetaldehyde, monohydroxyethyl terephthalate (MHET), bishydroxyethyl terephthalate (BHET), etc. are released from the resin material, and are collected in the dry circulation gas and removed from the resin material. In the drying system 20 of this embodiment, these impurities are decomposed by an oxidation-reduction reaction in the first catalyst tank 215.

[0032] The dry circulating gas from which impurities have been removed by decomposition and from which the oxygen concentration has been reduced by the oxidation-reduction reaction is supplied to the drying tank 211. In this case, oxygen has been consumed in the oxidation reaction, and the oxygen concentration of the dry gas is low, so that oxidative deterioration of the resin material is more effectively prevented. It is known that a similar effect can be obtained by using an inert gas as the drying gas, but the drying system 20 of the present invention can obtain the same effect as when an inert gas is supplied, without the need for an inert gas supply device.

[0033] Even though dry circulating gas is used, impurities in the gas are continuously removed, accelerating the removal of impurities from the resin material in the drying tank 211. In this way, the amount of impurities contained in the resin material is reduced, which reduces mold contamination caused by impurities occurring in the mold 140 of the injection molding machine 10, and also improves the quality of the manufactured preforms.

[0034] If the drying system 20 does not have the first catalyst tank 215, impurities contaminate the flow path of the drying system 20 by condensation, solidification, precipitation, etc. due to a drop in temperature. In particular, a lot of dirt may precipitate on the first filter 217 and the first heat exchanger 219, which may cause problems. When a lot of dirt precipitates due to impurities, frequent cleaning is required. Since product production stops during cleaning, frequent cleaning reduces the system's operating rate. In contrast, the present embodiment has the first catalyst tank 215, and impurities are removed by the oxidation-reduction reaction of the first catalyst tank 215, reducing the frequency of cleaning or replacement of the first filter 217 and the frequency of cleaning of the first heat exchanger 219, thereby lengthening the operating time. As a result, the productivity of preforms in this manufacturing system 1 is increased.

[0035] In contrast, when the drying system 20 does not include the first catalyst tank 215, the temperature of the dry gas in the drying tank 211 may have to be suppressed to, for example, 130°C or less due to the above-mentioned problem of impurity precipitation and the number of times of cleaning. On the other hand, according to the present embodiment, since the impurities can be decomposed in the first catalyst tank 215, the temperature of the dry gas can be made high, for example, 150-200°C. As a result, the efficiency of drying the resin material and removing impurities can be improved. For example, the amount of impurities such as acetaldehyde, MHET, and BHET generated as gas from the resin material is small at a low temperature, for example, 130°C, but is relatively large at a high temperature, for example, 160°C. Therefore, impurities that cannot be removed when the dry circulation gas is low can be removed by using a high-temperature dry circulation gas.

[0036] By being able to remove more of the impurities contained in the recycled resin material, dirt on the mold 140 of the injection molding machine 10 can be reduced and the frequency of cleaning of the mold can be reduced, which can result in improved productivity of preforms in the manufacturing system 1.

[0037] [Vent system configuration] The vent system 30 is a mechanism for removing impurities contained in the resin material melted in the melting unit 120 of the injection molding machine 10 through a vent port 123 provided in the melting unit 120. The low molecular weight impurities that can be removed include cyclic trimers (CT), BHET, MHET, acetaldehyde, water, and the like that come out of the resin material as gas.

[0038] Vent system 30 includes vacuum pump 311 to reduce the pressure at vent port 123 to lower the boiling point of impurities and recover gas from within melting unit 120. An eighth valve 341 is provided between vent port 123 and vent system 30, and the connection between melting unit 120 and vent system 30 is switched by opening and closing eighth valve 341.

[0039] When the eighth valve 341 is open and the vacuum pump 311 is operating, the vacuum level at the vent port 123 is, for example, 0.01 kPa-4 kPa, preferably 0.1 kPa-3 kPa. The pressure at the vent port 123 is monitored using a first pressure gauge 361.

[0040] In the vent system 30, between the vent port 123 and the vacuum pump 311, a second heater 313 for maintaining the gas temperature, a second catalyst tank 315 for decomposing impurities, and a second heat exchanger 321 for cooling are provided in this order from the vent port 123. An oxygen generator 317 for supplying oxygen is connected to the second catalyst tank 315 via a mass flow meter 319 for adjusting the amount of oxygen. The second catalyst tank 315 contains, for example, an active metal Pt / Pd-based catalyst.

[0041] Between the second heat exchanger 321 and the vacuum pump 311, there are provided a recovery tank 323 for recovering liquid generated by cooling by the second heat exchanger 321, and a cold trap 325 for further removing impurities from the cooled gas. The gas flow path via the recovery tank 323 and the cold trap 325 is connected to the vacuum pump 311 via a second filter 329. With this configuration, impurities in the gas are completely removed before it reaches the vacuum pump 311.

[0042] The temperature in the cylinder 121 of the melting unit 120 is, for example, about 300°C, and the temperature of the vent port 123 is also about this temperature. The gas containing impurities generated from the vent port 123 is led to the second catalyst tank 315 while being maintained at a temperature of about 300°C by the second heater 313. By maintaining the temperature in this manner, it is possible to effectively prevent the impurities from liquefying (condensing) or solidifying, and the impurities can be led to the second catalyst tank 315 in the gas phase as is. This prevents contamination of the path leading to the second catalyst tank 315. The second catalyst tank 315 is supplied with oxygen generated by an oxygen generator 317 and the amount of which is adjusted using a mass flow meter 319. The pressure in the second catalyst tank 315 is measured and adjusted by a second pressure gauge 362. The second catalyst tank 315 is heated and maintained at, for example, 150-550° C., more preferably 200-300° C., by a heater 316. In the second catalyst tank 315, the main impurities contained in the gas are oxidatively decomposed and removed.

[0043] The gas that has passed through the second catalyst tank 315 is cooled by the second heat exchanger 321. The liquid recovered product resulting from the cooling by the second heat exchanger 321 is recovered in the recovery tank 323. The recovery tank 323 is connected to the vacuum pump 311 via the second filter 329, and the degree of vacuum is maintained. In order to maintain the degree of vacuum, the recovery tank 323 is provided with a plurality of valves. That is, a ninth valve 342 is provided between the recovery tank 323 and the second heat exchanger 321, and a tenth valve 343 is provided between the recovery tank 323 and the vacuum pump 311. The recovery tank 323 is also connected to the outside via an eleventh valve 344, and is also connected to the outside via a twelfth valve 345. When the ninth valve 342 is opened to connect the second heat exchanger 321 to the recovery tank 323 in order to recover the liquid produced in the heat exchanger, the tenth valve 343 connected to the vacuum pump 311 is opened, and the eleventh valve 344 and the twelfth valve 345 are closed. In this manner, a necessary degree of vacuum is maintained in the recovery tank 323. When disposing of the liquid in the recovery tank 323, the ninth valve 342 and the tenth valve 343 are closed to cut off the connection to the main piping of the vent system 30, and the eleventh valve 344 and the twelfth valve 345 are opened.

[0044] The gas that has passed through the second heat exchanger 321 is sucked by the vacuum pump 311 through the cold trap 325. Moisture, resin components, impurities, and the like contained in the gas that has passed through the second heat exchanger 321 are further removed by the cold trap 325 so as not to flow into the vacuum pump 311. The cold trap 325 is a multiple type having a first cold trap 326 with a thirteenth valve 346 at its inlet and a fourteenth valve 347 at its outlet, and a second cold trap 327 with a fifteenth valve 348 at its inlet and a sixteenth valve 349 at its outlet. The multiple cold trap 325 allows the vent system 30 to operate continuously while maintaining the vacuum level of the main piping. For maintenance of the cold trap that has collected the impurities, a method of removing the trap device itself from the piping, disassembling and cleaning it, and then restoring it to its original state may be adopted, or a method of replacing the trap may be adopted.

[0045] [Vent system function] The vent system 30 can remove high-boiling point or sublimable low molecular weight impurities from the molten resin material in the melting unit 120 by lowering the boiling point at high temperature (e.g., about 280-320°C) and reduced pressure (e.g., about 0.01 kPa-4 kPa) and recovering the gas. The impurities mainly include CT, but may also include BHET, MHET, etc. By removing these impurities, mold contamination is reduced and the quality of the manufactured preforms is improved. In other words, the impurities removed here are substances that cause contamination of the mold 140, so by removing these impurities, the contamination of the mold 140 is suppressed. As a result, the interval between cleaning of the mold 140 is extended, and the productivity of preforms by the manufacturing system 1 is improved.

[0046] [Gas Reuse] A part of the gas that has passed through the catalyst tank of the drying system 20 may be added to the molten resin material in the melting unit 120 of the injection molding machine 10. For example, the gas obtained (gas obtained from the position indicated as (A) in the figure) may be introduced into the melting unit 120 (indicated as (C) in the figure) via the seventh valve 257 that is provided by branching downstream of the first catalyst tank 215 of the drying system 20. Also, the gas (gas obtained from the position indicated as (B) in the figure) that has been sucked into the vent system 30 and processed in the second catalyst tank 315 or the like may be introduced into the melting unit 120 (indicated as (C) in the figure). In this case, since this gas is decompressed, it is necessary to pressurize it.

[0047] [Gas reuse effect] The gas that has undergone oxidation-reduction reactions in these catalyst tanks has a low oxygen concentration, so by introducing this gas into the injection molding machine unit, the oxygen concentration in the molten resin part of the injection molding machine 10 is further reduced, making it possible to produce high-quality preforms with reduced levels of acetaldehyde and formaldehyde contained in the preforms.

[0048] [About the manufacturing system] The manufacturing system 1 including the combination of the drying system 20 and the vent system 30 of this embodiment can significantly reduce impurities contained in the resin material compared to a case without these mechanisms. The impurities can include low molecular weight substances derived from the resin material in particular. The substances derived from the resin material can include substances that can be generated during the synthesis process of the synthetic resin or during the depolymerization and decomposition process of the synthetic resin. As a result of reducing the impurities, it becomes possible to produce high-quality preforms. In addition, dirt in the system derived from impurities is reduced. As a result, the frequency of system maintenance work such as cleaning and replacement of the mold and drying system is reduced, the system operating time is extended, and production efficiency is improved.

[0049] It is noted that a part of the manufacturing system 1 may not be included. For example, only one or two of the drying system 20, the vent system 30, and the gas reuse system may be used. However, the vaporization temperature differs depending on the type of impurity, and the types of impurities that may be contained in the gas in the drying system 20 differ from the types of impurities that may be contained in the gas in the vent system 30 in the melting process. For this reason, in order to remove more impurities, it is preferable to use both the drying system 20 and the vent system 30.

[0050] Although the present invention has been described above by showing preferred embodiments, it goes without saying that the present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the present invention.

[0051] For example, the above embodiment has been described as a manufacturing system for preforms for PET bottles, but the manufacturing system 1 is not limited to the manufacture of preforms and can be used for the manufacture of various resin products using recycled PET materials. In addition, in the above embodiment, the resin material has been described as polyester mainly composed of polyethylene terephthalate or its recycled material, but this is not limited. It can of course be used for the manufacture of resin products using virgin materials as well as recycled materials. In addition, the above technology may be applied to a manufacturing system using other resin materials such as polyethylene furanoate (PEF), polyethylene naphthalate (PEN), polyethylene (PE), polypropylene (PP), nylon (Ny), polylactic acid (PLA), etc., not limited to PET. In this case, the temperature of the drying gas, the melting temperature, the pressure of the vent port, etc. can be appropriately changed.

[0052] The adsorption towers in the above-described embodiments may be replaced with various dehumidifiers, and the heat exchangers may be replaced with various coolers.

[0053] The contents of the documents cited in this specification and the Japanese application which is the basis of the Paris priority of this application are incorporated herein in their entirety by reference. [Explanation of symbols]

[0054] 1. Manufacturing System 10 injection molding machine 120 Melting Unit 121 Cylinder 122 Screw 123 Vent 130 Launch unit 140 Mold 20 Drying System 211 Drying Tank 213 First Heater 215 First catalyst tank 216 Heater 217 First Filter 219 First Heat Exchanger 221 First Fan 223 Adsorption tower 225 Drying heater 233 Nitrogen-enriched membrane 235 Second Blower 237 Regenerative Heater 251 First Valve 252 Second Valve 253 Third Valve 254 The Fourth Valve 255 The Fifth Valve 256 The Sixth Speech 257 Seventh Speech 258 Drain valve 259 Drain valve 30 Vent System 311 Vacuum Pump 313 Second Heater 315 Second catalyst tank 316 Heater 317 Oxygen Generator 319 Mass Flow Meter 321 Second Heat Exchanger 323 Recovery Tank 325 Cold Trap 326 First Cold Trap 327 Second Cold Trap 329 Second Filter 341 The Eighth Speech 342 The 9th Speech 343 The Tenth Speech 344 The 11th Speech 345 The 12th Speech 346 The 13th Speech 347 The Fourteenth Speech 348 The 15th Speech 349 16th Speech 361 First Pressure Gauge 362 Second Pressure Gauge

Claims

1. 1. A vent system for removing impurities from a molten resin material, comprising: a melting portion having a vent configured to heat and melt the resin material; a pump configured to reduce pressure at the vent; a catalyst tank provided in a flow path between the pump and the vent port, the catalyst tank containing a catalyst for decomposing impurities derived from the molten resin material that are generated as a gas from the molten resin material in the melting portion; an oxygen supply unit configured to supply oxygen to the catalyst tank while maintaining the reduced pressure state; A vent system comprising:

2. the resin material is a resin material containing polyethylene terephthalate as a main component, The temperature of the molten resin material at the vent port is 280-320° C. The pressure at the vent port is 0.01 kPa-4 kPa; The vent system of claim 1 .

3. The vent system according to claim 1 or 2, which is configured to maintain a temperature and pressure at which the impurities remain in a gaseous state from the vent port to at least the inside of the catalyst tank.

4. The vent system according to claim 1 , wherein the oxygen supply unit comprises an oxygen generator and a mass flow meter.

5. 5. The vent system according to claim 1, further comprising a heat exchanger having a liquid recovery tank and a cold trap disposed between the catalyst tank and the pump.

6. A drying system for drying a resin material using a circulating gas; a vent system for removing impurities from the molten resin material, the vent system being configured to use the resin material dried by the drying system; an injection molding machine that performs injection molding using the molten resin material; A manufacturing system comprising: The drying system comprises: a dehumidifier configured to dehumidify the gas to produce a dehumidified gas; a heater configured to heat the dehumidified gas to form a dry gas; A drying tank configured to accommodate a resin material and to blow the dry gas into the drying tank; a catalyst tank configured to circulate exhaust gas from the drying tank, the catalyst tank containing a catalyst for decomposing impurities attached to or adsorbed on the surface of the resin material placed in the drying tank, the impurities being included in the exhaust gas and originating from the resin material placed in the drying tank by vaporizing at the temperature of the drying gas; a cooler configured to cool the gas that has passed through the catalyst tank to produce a cooled gas, the cooled gas being configured to be sent to the dehumidifier for dehumidification; Equipped with The vent system comprises: a melting section having a vent port configured to heat and melt the resin material dried by the drying system; a pump configured to reduce pressure at the vent; a catalyst tank provided in a flow path between the pump and the vent port, the catalyst tank containing a catalyst for decomposing impurities derived from the molten resin material that are generated as gas from the molten resin material in the melting portion; Equipped with A manufacturing system configured such that gas after passing through the catalyst tank of the drying system and before reaching the cooler is introduced into the melting section.

7. A manufacturing system as described in claim 6, configured to introduce gas after passing through the catalyst tank of the vent system into the interior of the melting section.

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