Kneading device

Abstract

To provide a kneading device capable of improving a measurement accuracy when measuring properties of resin in-line between a first extruder and a second extruder, and stabilizing a quality of recycled resin.SOLUTION: A kneading device has a first extruder and a second extruder connected in series to the first extruder so that a resin extruded from the first extruder is input to the second extruder. An in-line measuring device is disposed in a flow path connecting the first extruder and the second extruder; and the first extruder has at least one of a vent mechanism and a compression dewatering mechanism.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a kneading device. [Background technology]

[0002] Various methods have been investigated for recovering and processing so that reuseable resin components that are not put to practical use, such as resin components recovered from waste products (consumer materials) and resin components that do not meet the standards for products for sale (off-grade materials) that are inevitably produced in the manufacturing process (hereinafter, the recovered resin components are also simply referred to as "recovered resins," and resin components obtained by processing recovered resins into a form suitable for reuse are also simply referred to as "recycled resins").

[0003] For example, Patent Document 1 describes a granulator having a first extruder into which waste plastics are fed and kneaded, a second extruder that feeds peroxide into the molten plastic extruded from the first extruder, and a molding device that pelletizes the molten plastic extruded by the second extruder. The granulator measures the MFR of the molten plastic extruded from the first extruder inline and adjusts the amount of peroxide fed into the second extruder based on the measured MFR of the molten plastic, thereby producing pellets with a predetermined MFR. The granulator also includes, between the first and second extruders, a filter that removes impurities from the molten plastic, a flow regulator that adjusts the flow rate of the molten plastic to measure the MFR, and an MFR meter, in that order. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2019-65092 Summary of the Invention [Problem to be solved by the invention]

[0005] The granulator described in Patent Document 1 measures the MFR after removing impurities with a filter in the flow path between the first extruder and the second extruder. However, according to new findings by the inventors, the configuration described in Patent Document 1 does not allow for accurate measurement of the MFR, and the quality of the resulting recycled resin is sometimes unstable. Furthermore, for example, when waste plastics are sorted in advance using a float-sink separator or the like, the water content of the waste plastics after sorting may be high, making it difficult to accurately measure the MFR and resulting in unstable quality of the recycled resin.

[0006] In view of the above problems, the present invention aims to provide a kneading device that can improve the measurement accuracy when measuring resin properties in-line between a first extruder and a second extruder, and stabilize the quality of recycled resin. [Means for solving the problem]

[0007] One aspect of the present invention for solving the above problems relates to the following kneading devices [1] to

[16] . [1] a first extruder; a second extruder connected in series to the first extruder so as to receive the resin extruded from the first extruder; an in-line measuring device is disposed in a flow path connecting the first extruder and the second extruder; The first extruder has at least one of a vent mechanism and a compression dewatering mechanism. Kneading equipment. [2] The first extruder has the compression dewatering mechanism, The first extruder melts and kneads the resin compressed and dehydrated in the compression and dehydration mechanism without melting it. [1] The kneading device according to the present invention. [3] A first filter, a gear pump, and a second filter are arranged in this order on the upstream side of the in-line measuring device in the flow path. The kneading device according to [1] or [2]. [4] a first extruder; a second extruder connected in series to the first extruder so as to receive the resin extruded from the first extruder; A flow path connecting the first extruder and the second extruder, A first filter, a gear pump, a second filter, and an in-line measuring device are arranged in this order. Kneading equipment. [5] The second filter has a higher filtering accuracy than the first filter. The kneading device according to [3] or [4]. [6] The first filter has a flat filter. The kneading device according to any one of [3] to [5]. [7] The first filter has a perforated metal filter. The kneading device according to any one of [3] to [6]. [8] The second filter is a screen changer. The kneading device according to any one of [3] to [7]. [9] The gear pump adjusts the pressure of the recovered resin introduced into the in-line measuring device through the second filter to 1 MPa or more and 35 MPa or less. The kneading device according to any one of [3] to [8].

[10] The second extruder has a water injection degassing mechanism. The kneading device according to any one of [1] to [9].

[11] The second extruder has two or more of the water injection degassing mechanisms.

[10] The kneading device according to

[10] .

[12] The water injection and degassing mechanism has a water injection hole and a vent port.

[10] or

[11] .

[13] The first extruder is a single-screw extruder; The second extruder is a twin-screw extruder. The kneading device according to any one of [1] to

[12] .

[14] The in-line measuring instrument is an in-line viscometer. The kneading device according to any one of [1] to

[13] .

[15] The second extruder has a feeder for adding additives to the second extruder. The kneading device according to any one of [1] to

[14] .

[16] The feeder adds an amount of resin to the second extruder that makes the viscosity of the resin extruded by the second extruder uniform.

[15] The kneading device according to

[15] . [Effects of the Invention]

[0008] According to the present invention, a kneading device is provided that can improve the measurement accuracy when measuring resin properties in-line between a first extruder and a second extruder, and can stabilize the quality of recycled resin. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic diagram showing the configuration of a kneading device according to one embodiment of the present invention. [Figure 2] FIG. 2 is an exploded view of the first filter. [Figure 3] Fig. 3A is a schematic perspective view of the second filter, and Fig. 3B is a schematic cross-sectional view of the second filter taken along line 3B-3B in Fig. 3A. [Figure 4] 4A is a schematic cross-sectional view of a first compression and dehydration mechanism, and FIG. 4B is a schematic cross-sectional view of a second compression and dehydration mechanism and a cylinder. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, the kneading device of the present invention will be described with reference to several embodiments.

[0011] FIG. 1 is a schematic diagram showing the configuration of a kneading device according to one embodiment of the present invention.

[0012] 1 includes a first extruder 110, a first filter 120, a gear pump 130, a second filter 140, an in-line viscometer 150, a second extruder 160, a cooling water tank 170, a draining section 180, and a pelletizer 190, which are arranged in this order in the direction of movement of the recovered resin. The first extruder 110, the first filter 120, the gear pump 130, the second filter 140, the in-line viscometer 150, and the second extruder 160 are connected by a resin flow path 100a, which is a pipe.

[0013] The first extruder 110 is an extruder that melts and kneads the recovered resin.

[0014] The recovered resin may be washed, crushed, and sorted before being fed into the first extruder 110. These processes can be performed by known methods. For example, the recovered resin is washed and crushed, and then wet-sorted by float-sink sorting. The resin is then dehydrated and dry-polished, and then dry-sorted by air sorting, color sorting, or optical sorting using infrared spectroscopy. These sorting processes can separate the recovered resin into different resin types and also remove foreign matter and impurities. These sorting processes may be performed for only one type or multiple types. The same type of sorting may also be performed multiple times, for example, optical sorting using different wavelengths may be performed multiple times.

[0015] The first extruder 110 has a feeder 112 and a cylinder 114. The cylinder 114 has a heating mechanism (not shown) that heats and melts the recovered resin fed from the feeder 112. A single screw 116 (not shown in FIG. 1) is disposed inside the cylinder 114, and the screw 116 rotates to knead the melted recovered resin.

[0016] The first extruder 110 has a vent mechanism 118, a first compression and dehydration mechanism 112a, and a second compression and dehydration mechanism 112b. The first extruder 110 shown in Figure 1 has two vent mechanisms 118. In Figure 1, the feeder 112 of the first extruder 110 has a first compression and dehydration mechanism 112a and a second compression and dehydration mechanism 112b. In Figure 1, the first compression and dehydration device is arranged from the front to the back of Figure 1.

[0017] FIG. 4A is a schematic cross-sectional view of the first compression and dehydration mechanism 112a. FIG. 4B is a schematic cross-sectional view of the second compression and dehydration mechanism 112b and the cylinder 114. The compression and dehydration mechanisms shown in FIGS. 4A and 4B have a barrel 112d, a compression screw 112e, and multiple drainage ports 112f. The compression and dehydration mechanism 112a in FIG. 4A also has a first hopper 112c and a discharge port 112g. The compression and dehydration mechanism 112b in FIG. 4B also has a second hopper 112h. The groove depth H and screw pitch W of the compression screw 112e both gradually decrease from the upstream portion to the downstream portion. As a result, the recovered resin introduced from the hopper 112c is compressed and dehydrated as it is transported from the upstream portion to the downstream portion. At this time, water generated by dehydration is discharged from the drainage port 112f. In Fig. 4A, the dewatered recovered resin is discharged from a discharge port 112g and sent to a second hopper 112h, while in Fig. 4B, the dewatered recovered resin is sent directly to a cylinder 114 of a first extruder 110.

[0018] 1 shows a configuration in which the first extruder 110 has a vent mechanism 118, a first compressing and dehydrating mechanism 112a, and a second compressing and dehydrating mechanism 112b, but the kneading apparatus 100 according to this embodiment may have only the vent mechanism 118 or one compressing and dehydrating mechanism. Specifically, in FIG. 1, the kneading apparatus 100 may have at least one of the vent mechanism 118, the first compressing and dehydrating mechanism 112a, and the second compressing and dehydrating mechanism 112b. In order to facilitate the removal of moisture from the recovered resin, the first extruder 110 preferably has a vent mechanism 118, more preferably has the vent mechanism 118 and the first compression dehydration mechanism 112a or the second compression dehydration mechanism 112b, even more preferably has the vent mechanism 118 and the second compression dehydration mechanism 112b, and most preferably has the vent mechanism 118, the first compression dehydration mechanism 112a, and the second compression dehydration mechanism 112b.

[0019] The recovered resin may contain moisture that was mixed in during recovery or moisture from cleaning. This moisture may evaporate in the first extruder 110 and become water vapor, which may cause foaming in the recovered resin. When foaming occurs, the flow resistance of the kneaded recovered resin decreases, and the viscosity measured by the in-line viscometer 150 tends to decrease. In contrast, in this embodiment, the first extruder 110 uses the vent mechanism 118, the first compression and dewatering mechanism 112a, and the second compression and dewatering mechanism 112b to remove moisture from the recovered resin, thereby suppressing foaming and enabling more accurate viscosity measurement by the in-line viscometer 150.

[0020] The provision of the vent mechanism 118, first compression and dehydration mechanism 112a, and second compression and dehydration mechanism 112b is preferable because sufficient dehydration can be performed, allowing accurate viscosity measurement without the need to heat and dry the recovered resin at 100°C or higher before feeding it into the first extruder. By not heating and drying the recovered resin at 100°C or higher, deterioration of the material due to chemical reactions caused by heating can be suppressed, thereby improving the quality of the recycled resin.

[0021] From the viewpoint of easily suppressing deterioration of the material caused by heating, it is preferable that the first compressing and dehydrating mechanism 112a and the second compressing and dehydrating mechanism 112b compress and dehydrate the recovered resin without melting it.

[0022] Similarly, the inclusion of the vent mechanism 118, the first compression and dehydration mechanism 112a, and the second compression and dehydration mechanism 112b allows for sufficient dehydration, making it easier to achieve the effects of the present invention when recovered resin that has been previously sorted using a float-sink separator or the like is fed into the first extruder. Specifically, this is suitable when the water content of the recovered resin before being fed into the first extruder is 10% or more, more suitable when the water content of the recovered resin is 25% or more, and even more suitable when the water content of the recovered resin is 40% or more.

[0023] The recovered resin thus melted and kneaded is extruded by the first extruder 110. The extruded recovered resin flows through the resin flow path 100a and is transported to the first filter 120.

[0024] FIG. 2 is an exploded view of the first filter 120. In this embodiment, a filter device with a continuous foreign matter discharge mechanism is used as the first filter 120. Specifically, the first filter 120 has a pair of flat filters 122a and 122b arranged opposite each other inside a housing 121 having an inlet 121a through which the recovered resin flows. The recovered resin that flows into the housing 121 through the inlet 121a is introduced into the space between the intermediate ring 123 and the filters 122a and 122b. The introduced recovered resin passes through one of these filters and flows between the filter 122a and the side cover 124a or between the filter 122b and the connecting holder 124b, and is then discharged from the outlet 121b located on the opposite side of the inlet 121a. Both the filters 122a and 122b are metal filters obtained by laser drilling holes in a metal plate.

[0025] The first filter 120 has scrapers 125a and 125b arranged on the inner surfaces of filters 122a and 122b, respectively (the side facing the other filter). Scrapers 125a and 125b are coaxially supported by a rotating shaft 126, and both are rotated by a motor 127 along the surfaces of filters 122a and 122b. As the recovered resin passes through filters 122a and 122b, foreign matter is removed from the filter surfaces. The removed foreign matter is then discharged from a discharge flow path 128 below. With the above-described configuration, the first filter 120 continuously discharges foreign matter while filtering the recovered resin. Although not shown in FIG. 2, the first filter 120 may also include shims, bearings, a heater for heating the recovered resin, a reducer, and the like.

[0026] The first filter 120 removes large foreign matter contained in the recovered resin upstream of the gear pump 130. This prevents the gear pump 130 from stopping or overtorque due to foreign matter. In this case, by using perforated metal plates as filters 122a and 122b and increasing the area of ​​filters 122a and 122b, the recovered resin can be filtered at low pressure. This makes it difficult for foreign matter to pass through the filters, thereby improving the efficiency of foreign matter removal. In other words, the first filter 120 is preferably a filter that filters the recovered resin at a lower pressure than the second filter 140. Furthermore, metal filters are less likely to be damaged by foreign matter, such as metal fragments, which are often contained in recovered resin, reducing the frequency of filter replacement. Furthermore, since foreign matter can be removed from the filter surface using a scraper, continuous filtration is possible without stopping the production of recovered resin. Using perforated metal plates as filters 122a and 122b allows for efficient removal of foreign matter from the filter surface using a scraper.

[0027] In order to increase the efficiency of removing foreign matter from the recovered resin, the opening diameter of the filters 122a and 122b is preferably 74 μm or more and 840 μm or less, and more preferably 105 μm or more and 420 μm or less.

[0028] In this way, the recovered resin is filtered through the first filter 120. The filtered recovered resin flows through the resin flow path 100a and is transported to the gear pump .

[0029] Any known gear pump may be used as the gear pump 130. For example, a gear pump having a pair of gears that are arranged in a housing and rotate while meshing with each other can be used.

[0030] The gear pump 130 increases the flow pressure of the recovered resin flowing into the second filter 140 and the in-line viscometer 150. For example, the gear pump 130 preferably adjusts the flow pressure of the recovered resin flowing into these to 1 MPa or more and 35 MPa or less, and more preferably to 2 MPa or more and 20 MPa or less.

[0031] The recovered resin, whose flow pressure has been adjusted by the gear pump 130, flows through the resin flow path 100a and is transported to the second filter 140.

[0032] FIG. 3A is a schematic perspective view of second filter 140. FIG. 3B is a schematic cross-sectional view of second filter 140 taken along line 3B-3B in FIG. 3A. Second filter 140 has two hollow metal pillars 143a and 143b, each with numerous openings on its surface, wrapped with filters 142a and 142b, inside housing 141, which has inlet 141a through which recovered resin flows. The recovered resin that flows into housing 141 from inlet 141a passes through filter 142a or 142b, enters metal pillar 143a or 143b, flows through flow path 144a or 144b, and is discharged from outlet 141b.

[0033] The second filter 140 is a dual-piston screen changer. When replacing one of the filters 142a and 142b, the metal column is pushed into the replacement chamber 145 to replace the filter. At this time, the other filter can continue to be used for filtration. This allows for continuous filtration without stopping the production of recovered resin when replacing the filter.

[0034] The second filter 140 filters the recovered resin with higher filtration accuracy than the first filter 120. It is desirable to precisely remove foreign matter from the recovered resin flowing into the in-line viscometer 150 to prevent a decrease in measurement accuracy due to the inclusion of foreign matter. Therefore, the second filter 140 filters the recovered resin using a filter with a smaller mesh size than the first filter. However, passing the recovered resin through a filter with a smaller mesh size results in a large pressure loss during passage. In contrast, in this embodiment, by providing a gear pump 130 upstream of the second filter 140, a constant amount of recovered resin is sent to the in-line viscometer 150 and the second extruder 160, even if the pressure loss in the second filter 140 increases. Therefore, viscosity measurement errors due to fluctuations in the amount of recycled resin sent to the in-line viscometer 150 are unlikely to occur, and reduced production efficiency of recycled resin, such as strand breakage, is also unlikely to occur.

[0035] Filters 142a and 142b may be flat filters or three-dimensional filters. Filters 142a and 142b may be made of metal woven into a mesh (woven wire mesh) or may be perforated metal filters. From the viewpoint of reducing the frequency of filter replacement, these filters are preferably sintered filters made by sintering metal.

[0036] The recovered resin is filtered in this manner by the second filter 140. The filtered recovered resin flows through the resin flow path 100a and is transported to the in-line viscometer 150.

[0037] Any known in-line viscometer may be used as the in-line viscometer 150. For example, an in-line viscometer having a slit-type pipe with a rectangular cross-sectional shape of the flow path, or a capillary-type pipe with a circular cross-sectional shape of the flow path, or an in-line viscometer having a combination of these pipes may be used.

[0038] The in-line viscometer 150 measures the melt viscosity of the recovered resin flowing through the flow path. In this embodiment, the amount of recovered resin to be fed into the first extruder 110 and the amount of additives to be fed into the second extruder 160 are adjusted based on the viscosity measured by the in-line viscometer 150 and the melt flow rate (MFR) calculated from the viscosity. This makes it possible to stabilize the quality of the recycled resin obtained. In this embodiment, the viscosity of the recovered resin from which foreign matter has been precisely removed by the second filter 140 is measured, so the accuracy of viscosity measurement by the in-line viscometer 150 can also be improved. As a result, the quality of the recycled resin obtained can be more highly stabilized.

[0039] The in-line viscometer 150 may be any known viscometer that extracts a portion of the recovered resin and measures its viscosity. For example, devices for measuring in-line viscosity are introduced in R. Gendron, L.E. Daigneault, J. Cell. Plast., 35, 221 (1999) and M. Lee, C.B. Park, and C. Tzoganakis, Polym. Eng. Sci., 39, 99 (1999). Alternatively, a viscometer having a viscosity measurement pipe, as described in International Publication No. 2023 / 214528 by the present inventors, may be used.

[0040] The recovered resin, whose viscosity has been measured by the in-line viscometer 150, flows through the resin flow path 100a and is transported to the second extruder 160.

[0041] The second extruder 160 is an extruder connected in series with the first extruder 110. The second extruder 160 is an extruder that further kneads the recovered resin that has been melt-kneaded in the first extruder 110.

[0042] The second extruder 160 has a feeder 162, a cylinder 164, and water injection and degassing mechanisms 166a to 166c. The cylinder 164 has a heating mechanism (not shown) and heats the recovered resin introduced from the resin flow path 100a and the additives introduced from the feeder 162 to melt and knead them. A twin screw (not shown) is arranged inside the cylinder 164, and the screw rotates to knead the melted recovered resin and the additives.

[0043] The feeder 162 is an inlet for introducing viscosity-adjusting additives, viscosity-adjusting resins, and other additives for adjusting the quality of the recycled resin (e.g., additives such as crosslinking agents, peroxides, chain extenders, colorants, deodorizers, fragrances, stabilizers, antioxidants, and crystal nucleating agents; fillers such as rubber, talc, and calcium carbonate; and reinforcing fiber materials such as glass fiber, carbon fiber, and organic fiber) into the cylinder 164. Only one feeder 162 may be provided, or multiple feeders 162 may be provided. In this embodiment, the feeder 162 adds an amount of resin to uniformize the viscosity of the recycled resin extruded by the second extruder 160 under the control of a control unit (not shown), depending on the viscosity measured by the in-line viscometer 150. The added resin may be virgin material or recycled resin with a known viscosity.

[0044] The feeder 162 may have a dry blender such as a tumble mixer, a V-blender, a ribbon blender, a two-roll mixer, a shaker, or a buffer tank with a rotor inside, to mix the additives to be added.

[0045] Each of the water injection and degassing mechanisms 166a to 166c has a water injection hole 167 and a vent port 168. Water is injected into the cylinder 164 through the water injection hole 167 and degassed through the vent port 168. The recovered resin may contain residual substances that could not be removed by the first filter 120 and the second filter 140, such as beverage residue, food residue, and cleaning residue. If these substances (odor-causing substances) remain, the recycled resin may emit an odor. Furthermore, the recycled resin may contain impurities such as chlorine. These impurities may cause the recycled resin to discolor. In this embodiment, two or more water injection and degassing mechanisms (three in this embodiment) are used to remove these odor-causing substances and impurities, preventing them from being mixed into the recycled resin.

[0046] The vent port 168 may have a mechanism such as a side vent stuffer for returning the resin component to the inside of the cylinder 164 and releasing only the volatilized gas component to the outside.

[0047] The second extruder 160 can uniformly disperse additives by kneading with twin screws. In addition, because the extruder with twin screws has high degassing properties, it also has a high performance in removing odorous substances and impurities using a water injection degassing mechanism.

[0048] The second extruder 160 extrudes the melted and kneaded recovered resin. The extruded recovered resin is cooled in a cooling water tank 170, dehydrated in a draining section 180, and cut into pellets of a predetermined size in a pelletizer 190. In this way, recycled resin pellets can be produced.

[0049] The pelletizing method is not particularly limited, and known pelletizers such as strand cut type, watering hot cut type, and underwater cut type can be used.

[0050] By carrying out these treatments, recycled resin can be produced from recovered resin.

[0051] In the above-described kneading apparatus 100, the first extruder 110 has at least one of a vent mechanism 118, a first compression dewatering mechanism 112a, and a second compression dewatering mechanism 112b, or a flow path connecting the first extruder 110 and the second extruder 160 has a first filter 120, a gear pump 130, a second filter 140, and an in-line measuring device 150 arranged in this order. This reduces impurities such as moisture and foreign matter, suppresses the generation of bubbles due to moisture contamination, and improves the efficiency of removing foreign matter from the recovered resin, thereby improving the accuracy of viscosity measurement by the in-line viscometer 150.

[0052] In particular, when two-stage filtration is performed using the first filter 120 and the second filter 140, the first filter 120 removes foreign matter from the recovered resin with low filtration accuracy, and then the gear pump 130 increases the flow pressure to allow the second filter 140 to remove the foreign matter more precisely with high filtration accuracy. This increases the efficiency of foreign matter removal and improves the accuracy of viscosity measurement by the in-line viscometer 150.

[0053] From the viewpoint of making it easier to improve the accuracy of viscosity measurement by the in-line viscometer 150, it is preferable that the first extruder 110 of the kneading apparatus 100 has at least one of a vent mechanism 118, a first compression dehydration mechanism 112a, and a second compression dehydration mechanism 112b, and that the first filter 120, a gear pump 130, a second filter 140, and an in-line measuring instrument 150 are arranged in this order in the flow path connecting the first extruder 110 and the second extruder 160.

[0054] In this case, the first filter 120 uses flat, perforated metal filters 122a and 122b. This allows filtration to be performed at low flow pressure, improving the efficiency of removing large contaminants. The first filter 120 also has a continuous contaminant discharge mechanism that uses scrapers 125a and 125b to remove contaminants from filters 122a and 122b. This allows for continuous, stable production of recycled resin and also prevents sudden pressure increases in the first filter 120.

[0055] Furthermore, filtration is performed by a screen changer in the second filter 140. This allows for continuous and stable production of recycled resin, and also prevents foreign matter from being mixed in during filter replacement.

[0056] By increasing the measurement accuracy of the in-line viscometer 150 in this way, it is possible to appropriately control the type and amount of additives added from the feeder 162 in the second extruder 160, thereby improving the quality of the recycled resin. Furthermore, although the quality of recovered resin varies greatly depending on its source (recovery source), it is possible to standardize the quality of the recycled resin by appropriately controlling the type and amount of additives added in the second extruder 160.

[0057] Furthermore, the second extruder 160 has two or more water injection / deaeration mechanisms 166a to 166c, which remove odorous substances and impurities from the recovered resin, suppress odor and coloration, and improve the quality of the recycled resin.

[0058] In this embodiment, the first extruder 110 is a single-screw extruder having a conical screw 116, and the second extruder 160 is a twin-screw extruder. The first extruder 110 can thoroughly knead coarsely pulverized materials such as fluff and flakes. The second extruder 160 can thoroughly knead the recycled resin and additives that have already been kneaded, and uniformly disperse them.

[0059] In this embodiment, the first extruder 110 and the second extruder 160 are connected by a resin flow path 100a, which is a pipe, and the space between them is a closed system that is not open to the outside air. This makes it possible to prevent deterioration in the quality of the recycled resin due to the intrusion of sand and dust from the outside air. In this embodiment, the gear pump 130 can adjust the flow pressure and flow rate of the recovered resin to a constant level, so fluctuations in these factors are minimal, enabling stable operation even in a closed system.

[0060] [Other embodiments] It should be noted that the above-described embodiments are merely examples of the present invention, and the present invention is not limited to the above-described embodiments. It goes without saying that various other embodiments are possible within the scope of the concept of the present invention.

[0061] For example, in each of the above-described embodiments, the types and numbers of screws of the first extruder and the second extruder are not limited to those described above and may be changed as appropriate depending on the production conditions of the recycled resin. The types of the first filter and the second filter may also be changed as appropriate. When continuous operation is not essential, a filter that stops operation and filters the material may be used. Furthermore, the number of filters is not limited to two, and additional filters may be used.

[0062] In the above-described embodiment, the viscosity of the recycled resin is uniformed by changing the amount of resin added to the second extruder according to the viscosity measured by the in-line viscometer. However, other in-line measuring devices may be used instead of or in addition to the in-line viscometer. Examples of other in-line measuring devices include an in-line foreign object detector, a metal detector, etc.

[0063] The information on the recovered resin measured by these inline measuring devices may be used to adjust the quality of the recycled resin in the second extruder, or may be stored in a storage unit (not shown) and used as training data for machine learning together with the source of the recovered resin, etc. By learning these as training data, a predictor that predicts the properties of the recovered resin can be created.

[0064] The extruder described above is described as adding polyethylene or polypropylene additive resin to recycled resin containing polyethylene and polypropylene in a second extruder. However, the resin types are not limited to these, including off-grade materials and separated and sorted recycled materials, such as polyethylene alone, polypropylene alone, and polyester alone. The recycled resin and the added resin can be a combination of various resins, including polyamide, polystyrene, acrylonitrile-butadiene-styrene copolymer (ABS), polyvinyl chloride (PVC), polycarbonate, polyurethane, and polyester. The polyester can be polylactic acid, polyethylene terephthalate, etc.

[0065] The second extruder may extrude the recycled resin into any known shape, including a sheet, a film, a rod, a plate, a pipe, a modified cross-section molded product, a strand, etc. Alternatively, a known molding machine may be disposed downstream of the extrusion section, and the extruded recycled resin may be molded into a predetermined shape.

[0066] The kneading device may also have a second measuring device that measures the viscosity and other properties of the recycled resin extruded from the second extruder in a molten state. The second measuring device may be an in-line viscometer similar to the in-line viscometer 150 described above, or another measuring device. [Industrial Applicability]

[0067] The kneading device of the present invention can obtain recycled resin with a predetermined viscosity from recovered resin.The kneading device of the present invention can homogenize the viscosity of recycled resin obtained from consumer materials and off-grade materials and regenerate them into recycled resin that can be easily used for a variety of applications.This is expected to expand the range of reuse of these resins and contribute to improving the efficiency of resin recycling. [Explanation of symbols]

[0068] 100 kneading device 100a Resin flow path 110 First Extruder 112 Feeder 112a First compression and dehydration mechanism 112b Second compression dehydration mechanism 112c First Hopper 112d barrel 112e compression screw 112f drain 112g outlet 112h Second hopper 114 cylinders 116 Screw 118 Vent mechanism 120 First Filter 121 Case 121a Inlet 121b Outlet 122a, 122b filters 123 Intermediate Ring 124a Side cover 124b Connecting Holder 125a, 125b scraper 126 Rotation Axis 127 Motor 128 Discharge flow path 130 Gear Pump 140 Second Filter 141 Case 141a Inlet 141b Outlet 142a, 142b filters 143a, 143b metal pillar 144a, 144b flow channel 145 Exchange room 150 In-line Viscometer 160 Second Extruder 162 Feeder 164 cylinders 166a~166c Water injection and degassing mechanism 167 Water injection hole 168 Vent port 170 Cooling Water Tank 180 draining section 190 Pelletizer

Claims

1. a first extruder; a second extruder connected in series to the first extruder so as to receive the resin extruded from the first extruder; an in-line measuring device is disposed in a flow path connecting the first extruder and the second extruder; the first extruder has at least one of a vent mechanism and a compression dewatering mechanism; Kneading equipment.

2. the first extruder has the compression dewatering mechanism, the first extruder melts and kneads the resin compressed and dehydrated in the compression and dehydration mechanism without melting it; The kneading device according to claim 1 .

3. A first filter, a gear pump, and a second filter are arranged in this order on the upstream side of the in-line measuring device in the flow path. The kneading device according to claim 1 .

4. a first extruder; a second extruder connected in series to the first extruder so as to receive the resin extruded from the first extruder; A flow path connecting the first extruder and the second extruder, A first filter, a gear pump, a second filter, and an in-line meter are arranged in this order. Kneading equipment.

5. The second filter has a higher filtering accuracy than the first filter. The kneading device according to claim 3 or 4.

6. The first filter has a flat filter. The kneading device according to claim 3 or 4.

7. The first filter comprises a perforated metal filter. The kneading device according to claim 3 or 4.

8. The second filter is a screen changer. The kneading device according to claim 3 or 4.

9. The gear pump adjusts the pressure of the recovered resin introduced into the in-line measuring device through the second filter to 1 MPa or more and 35 MPa or less. The kneading device according to claim 3 or 4.

10. The second extruder has a water injection degassing mechanism. The kneading device according to any one of claims 1 to 4.

11. The second extruder has two or more of the water injection degassing mechanisms. The kneading device according to claim 10.

12. The water injection and degassing mechanism has a water injection hole and a vent port. The kneading device according to claim 10.

13. the first extruder is a single-screw extruder; The second extruder is a twin-screw extruder. The kneading device according to any one of claims 1 to 4.

14. The in-line measuring instrument is an in-line viscometer. The kneading device according to any one of claims 1 to 4.

15. The second extruder has a feeder for adding additives to the second extruder. The kneading device according to any one of claims 1 to 4.

16. The feeder adds to the second extruder an amount of resin that makes the viscosity of the resin extruded by the second extruder uniform. The kneading device according to claim 15.

Images