Regenerated resin manufacturing equipment

Abstract

To provide a recycled resin manufacturing apparatus that can adjust for variance in MI of a waste plastic caused by a difference in standard, a difference in deterioration, etc.SOLUTION: A recycled resin manufacturing apparatus 1 that molds a waste resin and obtains a granular recycled resin pellet includes: an extruder 2 that melts and kneads the waste resin; a viscosity measuring instrument 9 that measures a viscosity of the waste resin in a molten state; a granulation unit 3 that converts the waste resin whose viscosity has been measured into a solid granule; and a separation mechanism 11 that separates the granule into a standard pellet within a predetermined viscosity range and a non-standard pellet outside the predetermined viscosity range, based on measurement information of the viscosity measuring instrument 9. As a result, it is possible to continuously determine whether the granules molded by the granulation unit are within or outside the standard during a production process of the recycled resin pellets, and to obtain the recycled resin pellets with good moldability.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a technology for melting and kneading waste resin and recycling it as recycled resin pellets. [Background technology]

[0002] Traditionally, waste plastics have been collected and recycled. PET bottles, food trays, and other waste materials are already collected from consumers and recycled as recycled resin pellets. However, currently, only a portion of plastic products are recycled, and much of the waste resin is not recycled but is instead disposed of by incineration or landfill. From the perspective of reducing plastic waste and conserving resources, it is necessary to be able to recycle a variety of items.

[0003] Examples of resin products that need to be recycled include tarps and flexible containers. Tarps are used as temporary covers at construction sites and as emergency repairs for roofs damaged by typhoons, and are often discarded once the construction is complete. Flexible containers are large bags used to store resin raw materials, agricultural products, etc., and many of them are one-way (disposable) items.

[0004] Many blue tarps and flexible containers commonly use a woven fabric made from thread known as flat yarn. Flat yarn is a thread made by slitting a film into narrow widths and stretching it longitudinally. A method for producing recycled flat yarn using recycled resin pellets is described, for example, in Patent Document 1, in which two types of thermoplastic waste plastic materials with different MI (melt index) are mixed together to form recycled material pellets with an MI value of 0.6 g / 10 min to 0.8 g / 10 min, enabling stable production of tension and elongation. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-105742 Summary of the Invention [Problem to be solved by the invention]

[0006] In terms of recycling, horizontal recycling, in which used waste materials are recycled back into the original products, is the ideal approach from the perspective of reducing waste emissions. It is also necessary to recycle waste materials such as blue tarps and flexible containers into recycled flat yarn.

[0007] However, the degree of deterioration of waste materials such as blue tarps and flexible containers varies greatly from piece to piece due to differences in the length of use, the environment in which they are used, and the design specifications. In pieces that have been deteriorated by ultraviolet light, the molecular chains in the resin are cut, resulting in an extremely high MI.

[0008] Additionally, especially in blue tarps and some flexible containers, a resin layer is often laminated using extrusion lamination to achieve waterproofing. It is extremely difficult to forcibly separate the laminated resin layer from the flat yarn. For this reason, the flat yarn and resin layer must be mixed together rather than forcibly separated. However, since the MI of the resin layer is generally higher than that of the flat yarn, when they are mixed together the MI increases depending on the proportion of the resin layer. Furthermore, products widely collected from the general public naturally have inconsistent manufacturers and specifications, which also causes variations in MI.

[0009] To produce recycled flat yarn as in Patent Document 1, it is necessary to select and use waste thermoplastic plastics with MI within a certain range. When using waste plastics such as blue tarps or flexible containers, it is first necessary to identify the MI of each individual plastic. However, the weight of blue tarps and flexible containers is less than a few kilograms, so it is not practical to measure the MI of each individual plastic. Therefore, to produce recycled flat yarn as in Patent Document 1, it has been necessary to use factory scrap with a known origin, such as waste from the edges of single-layer film.

[0010] The present invention solves the above-mentioned problems and aims to provide a recycled resin manufacturing device that can adjust the variations in MI of waste plastics that arise due to differences in specifications, deterioration, etc. [Means for solving the problem]

[0011] In order to achieve the above-mentioned object, the present invention provides a recycled resin manufacturing apparatus that molds waste resin to obtain granular recycled resin pellets, and is characterized by comprising an extruder that melts and kneads the waste resin, a viscosity measuring device that measures the viscosity of the molten waste resin, a granulation unit that converts the waste resin whose viscosity has been measured into solid granules, and a sorting mechanism that sorts the granules into standard pellets that are within a predetermined viscosity range and non-standard pellets that are outside the predetermined viscosity range based on the measurement information of the viscosity measuring device.

[0012] According to this configuration, in the recycled resin pellet manufacturing process, the granules formed in the granulation unit can be sorted into standard and non-standard pellets based on the viscosity at the extrusion temperature. Viscosity is a different index from the MI used in the conventional technology, but MI is an index that indicates the fluidity of the molten state, and MI and viscosity are closely related. By utilizing viscosity information that is easy to measure in-line, it is possible to continuously determine whether the granules formed in the granulation unit are within the standard or not, and to obtain recycled resin pellets with good moldability.

[0013] The recycled resin manufacturing apparatus preferably includes a waste material input section for inputting waste resin into the extruder, and a re-input path for re-inputting non-standard pellets separated by the sorting mechanism into the waste material input section as waste resin.

[0014] According to this configuration, non-standard pellets can be re-introduced and recycled as standard pellets, thereby increasing the yield of standard pellets.

[0015] The recycled resin manufacturing apparatus preferably includes an adjuster input section for inputting a viscosity adjuster for adjusting the viscosity of the waste resin.

[0016] According to this configuration, viscosity adjustment can be easily performed, making it easier to recycle the pellets into standard pellets.

[0017] The recycled resin manufacturing device is equipped with a gear pump that discharges a constant amount of molten waste resin, and can adjust the supply amount of the viscosity adjuster based on rotation information of the gear pump.

[0018] According to this configuration, it is possible to adjust the viscosity of the waste resin based on the rotation information of the gear pump, and the yield of pellets within the standard can be further increased. [Effects of the Invention]

[0019] By using the recycled resin manufacturing apparatus of the present invention, recycled resin pellets with stable viscosity characteristics can be obtained. Non-standard pellets that do not meet the viscosity characteristics can be separated. Viscosity can be adjusted by re-introducing non-standard pellets, and recycled resin pellets with stable viscosity characteristics can be obtained in high yield. [Brief explanation of the drawings]

[0020] [Figure 1] 1 is a schematic diagram showing an example of a recycled resin manufacturing apparatus according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0021] The following describes a preferred embodiment for carrying out the present invention with reference to the drawings. The present invention is not limited to this embodiment, and can be modified as appropriate within the scope of the technical concept of the present invention.

[0022] As shown in FIG. 1, the recycled resin manufacturing apparatus 1 of the present invention includes an extruder 2 that melts and kneads waste resin, and a granulation unit 3 that turns the melted and kneaded waste resin into solid granules.

[0023] The waste resin used in the recycled resin manufacturing apparatus 1 of the present invention is not particularly limited as long as it is of a type and shape that can be fed into the extruder 2, but it is preferably a thermoplastic resin such as polyolefin, polyamide, or polyester, and is preferably a pulverized or powdered material thereof.

[0024] In Fig. 1, waste resin is sent to waste material input section 4 from path A. In addition to opening 4a for path A, waste material input section 4 in Fig. 1 is equipped with hopper 4b, weighing device 4c, feeder 4d, and opening 4e for path E, and waste resin sent from path A is collected in hopper 4b, weighed by weighing device 4c, and then sent towards extruder 2 through feeder 4d.

[0025] The mechanism for sending waste resin to route A is optional. When using resin products crushed using a crushing device such as a cutter compactor as the waste resin, route A and the cutter compactor may be connected via a screw feeder or the like and sent into the waste material input section 4. The resin may be crushed in a different location and then sent by connecting a pneumatic transport mechanism to route A. The work of sending waste resin to the waste material input section 4 may be done manually, or the opening of hopper 4b may be used as route A and the waste resin may be sent directly to hopper 4b.

[0026] The recycled resin manufacturing apparatus 1 in Fig. 1 is equipped with a waste material input section 4 and an adjuster input section 5. The adjuster input section 5 supplies a viscosity adjuster. The viscosity adjuster referred to in the present invention is a material that can adjust the viscosity of the waste resin by mixing it with the waste resin, and may be an additive that is generally known to have a viscosity adjusting effect, such as a thickener, a rheology adjuster, or a peroxide. However, viscosity adjustment is also possible by mixing a low-viscosity resin with a high-viscosity resin, and a resin of the same type but with a different viscosity from the waste resin can also be used as a viscosity adjuster.

[0027] In Fig. 1, the viscosity adjuster is sent to the adjuster charging section 5 from the path B. In addition to the opening 5a of the path B, the adjuster charging section 5 in Fig. 1 is equipped with a hopper 5b, a measuring device 5c, and a feeder 5d, and the viscosity adjuster sent from the path B is stored in the hopper 5b, and then measured, and the amount required to adjust the viscosity of the waste resin is sent to the extruder 2 according to the control of the feeder 5d.

[0028] The method of sending the viscosity adjusting material to path B is arbitrary, and the viscosity adjusting material may be sent by connecting a pneumatic transport mechanism to path B, or the viscosity adjusting material may be sent directly to hopper 5b using the opening of hopper 5b as path B.

[0029] In FIG. 1, waste resin sent from waste material input section 4 and viscosity adjuster sent from adjuster input section 5 are mixed in mixer 6 and then sent into extruder 2. In extruder 2, the resin sent into extruder 2 is melted and kneaded at a temperature set arbitrarily. The screw and cylinder structure of extruder 2 are arbitrary and are selected appropriately taking into account the waste resin. From the viewpoint of using waste resin, it is preferable to select an extruder 2 with a vent.

[0030] The recycled resin manufacturing apparatus 1 shown in Figure 1 is equipped with a screen changer 7 (7a, 7b), a gear pump 8, a viscosity measuring instrument 9, and a die 10. In the apparatus of Figure 1, waste resin that has been molten by the extruder 2 passes through the first screen changer 7a, the gear pump 8, the second screen changer 7b, the viscosity measuring instrument 9, and the die 10, and is then turned into granules by the granulation unit 3.

[0031] The screen changer 7 in Figure 1 is equipped with a mesh filter to remove foreign matter. It is included to facilitate easy replacement of the mesh filter, considering the use of recycled resin. While the installation of the screen changer 7 is optional, especially when recycling recycled resin from waste materials used outdoors, such as blue tarps, washing the recycled resin before use does not necessarily remove all foreign matter. Therefore, a mesh filter that is easy to replace is preferable, and the use of the screen changer 7 is preferred. In particular, when recycled resin is used in flat yarn, the flat yarn is a narrow tape stretched to a high magnification. If foreign matter is not sufficiently removed, the tape will break during stretching, making production difficult. Therefore, Figure 1 shows a first screen changer 7a and a second screen changer 7b, separated by a gear pump 8. After passing through the mesh filter of the first screen changer 7a, the gear pump 8 discharges the resin with sufficient pressure to pass it through the mesh filter of the second screen changer 7b, thereby removing foreign matter more efficiently than using multiple mesh filters in a single screen changer 7.

[0032] The gear pump 8 in Figure 1 is provided for the purpose of stabilizing and maintaining a constant discharge rate in the event of pressure changes in the molten waste resin. While the installation of the gear pump 8 is optional, since the gear rotation speed of the gear pump 8 changes in response to pressure changes in the waste resin, by transmitting information about the rotation change to the adjusting material input section 5, the amount of viscosity adjusting material supplied can be adjusted, thereby adjusting the viscosity of the waste resin. The waste resin may be passed through the gear pump 8 immediately after it has been molten in the extruder 2, but it is preferable to install at least one screen changer 7 before the gear pump 8, which also helps prevent breakdowns of the gear pump 8.

[0033] The viscosity meter 9 in FIG. 1 measures the viscosity of the molten waste resin. This viscosity is not limited to measurements in Pascal seconds or poises; any measurement that can quantify the viscosity at the extrusion temperature of the extruder 2 is acceptable. It is also possible to estimate and convert values ​​such as MI (melt index) and MFR (melt flow rate) into the viscosity. When using MI or MFR, it is important to note that while viscosity values ​​measured in Pascal seconds or poises increase with increasing viscosity, MI and MFR decrease with increasing viscosity. Furthermore, while measuring MI and MFR typically requires extrusion at a predetermined measurement temperature, this viscosity measurement is performed to standardize the viscosity based on the viscosity at the extrusion temperature in the recycled resin manufacturing apparatus 1. Therefore, when processing recycled resin pellets produced by the recycled resin manufacturing apparatus 1 of the present invention, it is preferable to extrude and mold them based on the extrusion temperature of the recycled resin manufacturing apparatus 1. This allows for particularly stable molding during processing of the recycled resin pellets. The viscosity meter 9 only needs to be installed in a location where the waste resin is in a molten state, and may be installed before or after the screen changer 7 or gear pump 8. However, it is preferable to measure in a state where foreign matter has been removed as much as possible, as this makes the viscosity meter 9 less likely to break down and the measured values ​​more reliable, and therefore the viscosity meter 9 is preferably installed after the screen changer 7.

[0034] The molten waste resin is sent to a die 10 and processed into granules (pellets) by a granulation unit 3. The granulation unit 3 shown in Figure 1 uses a hot-cut method in which the resin is cut with a rotary blade immediately after being extruded from a hole, and then cooled to form granules. The granulation method is not limited to this, and any conventionally known method can be used, such as a strand-cut method in which the resin is extruded into a long, thin strand, cooled, and then cut to form granules.

[0035] The resulting granules are sent to a sorting mechanism 11. Based on the measurement information from the viscosity measuring instrument 9, the sorting mechanism 11 separates the resulting granules into pellets that meet the specified viscosity range and pellets that fall outside the specified viscosity range. The sorting mechanism 11 in Figure 1 is equipped with a diverter-type air transport valve linked to the viscosity measuring instrument 9. This sorting mechanism 11 predicts the time it will take for the waste resin to solidify and turn into granules after passing through the viscosity measuring instrument 9, and can allocate the granules to a different route based on the viscosity measurement results when the waste resin passes through this valve. In Figure 1, pellets with a viscosity within the specified range are sent to route C as pellets that meet the specified viscosity range, and pellets with a viscosity outside the specified range are sent to route D.

[0036] In Figure 1, the routes for in-spec and out-spec pellets are divided into two, but additional routes may be added to allow for multiple sorting of out-spec pellets. For example, out-spec pellets may be further divided into three categories: high viscosity, low viscosity, and ultra-low viscosity. In this case, the viscosity of out-spec pellets sorted into the high viscosity or low viscosity categories can be adjusted by mixing them with other out-spec pellets or by mixing them with waste resin or a viscosity adjuster. Therefore, it is considered possible to adjust the viscosity of out-spec pellets to in-spec pellets by re-introducing them into the waste material input section 4 as waste resin. On the other hand, out-spec pellets sorted into the ultra-low viscosity category may be too deteriorated and difficult to reuse as recycled resin. In this case, it is desirable to discard them or repurpose them for another purpose rather than reuse them. If pellets are sorted into in-spec and out-spec pellets according to their viscosity characteristics as described above, or if out-spec pellets are sorted into multiple categories, these pellets can be used according to their characteristics.

[0037] The non-standard pellets sorted to route D can be stored in a container and manually transferred to the waste material input section 4, but in the recycled resin manufacturing apparatus 1 of Figure 1, route D and route E are connected by a pipe (not shown) to form a re-feeding route. The non-standard pellets sorted to route D are sent from route E via the re-feeding route to the waste material input section 4, where they can be re-input as waste resin.

[0038] The recycled resin manufacturing apparatus 1 in FIG. 1 is equipped with an adjuster feed section 5, which allows viscosity adjustment. However, when re-feeding non-standard pellets into the waste feed section 4, a viscosity adjuster may be mixed in between route D and route E to adjust the viscosity, and the non-standard pellets may then be re-feeded into the waste feed section 4. This allows the viscosity of the non-standard pellets to be adjusted based on the measured viscosity information before the viscosity is adjusted by the adjuster feed section 5, thereby more reliably adjusting the viscosity. One method of re-feeding is to install a second adjuster feed section in the re-feed path and add the viscosity adjuster at the timing when the non-standard pellets are sorted based on the viscosity measurement results of the viscosity meter 9.

[0039] The standard pellets obtained by the recycled resin manufacturing apparatus 1 of the present invention can be processed as recycled resin pellets into any plastic product in a separate process. In this case, the standard pellets may be used alone or mixed with other resins or other additives. [Example]

[0040] The present invention will be explained in more detail below with reference to examples, but these are merely examples and the present invention is not limited to the following examples.

[0041] Example 1 Used blue tarps were collected, washed, crushed, and then put into a cutter compactor to obtain crushed blue tarp waste. The collected blue tarps included Tarpee Sheet #3000, Tarpee Sheet #4000, and OS Sheet #2500 manufactured by Hagiwara Kogyo Co., Ltd., as well as a large number of blue tarps from unknown manufacturers, the duration of use of which was unknown.

[0042] In the recycled resin manufacturing apparatus 1 shown in FIG. 1, the crushed material of the blue tarp waste material obtained as described above was sent to the waste material input section 4 via route A. In the waste material input section 4, the crushed material was collected in a hopper 4b, weighed with a scale, and then sent to a mixer 6 by a feeder 4d. In addition, high-density polyethylene (density: 0.957 kg / m) was used as a viscosity modifier. 3 , MFR: 0.4g / 10min) was used, and this was sent to the adjuster feeding section 5 via route B. In the adjuster feeding section 5, the viscosity adjuster was stored in a hopper 5b, weighed, and sent to the mixer 6 under the control of a feeder 5d. The adjuster feeding section 5 was linked to the rotation of a gear pump 8, and the amount of viscosity adjuster sent to the mixer 6 changed according to the rotation of the gear pump 8.

[0043] The pulverized material and viscosity modifier were stirred in a mixer 6 and then melt-kneaded in an extruder 2. The extrusion temperature at this time was set to 220°C. The extruder 2 was first connected to a first screen changer 7a, and the mixture passed through its mesh filter. After the discharge was adjusted by a gear pump 8, the mixture passed through a mesh filter of a second screen changer 7b. The viscosity of the mixture of pulverized material and viscosity modifier was measured by a viscosity measuring instrument 9 (a CMR4 online rheometer manufactured by Dynisco), and then the mixture was sent to a die.

[0044] The mixture of the pulverized material and viscosity modifier was extruded in a molten state through a die 10 and turned into granules through a hot-cut granulation unit 3. After drying, the granules were sent to a diverter-type pneumatic conveying valve 11, which resulted in recycled resin pellets X being separated into route C and recycled resin pellets X' being separated into route D. The diverter-type pneumatic conveying valve 11 was adjusted to be linked to the measurement results of the viscosity meter 9. The measured viscosity was set to estimate and display the MFR, and it was set so that when the measurement value from the viscosity meter 9 indicated an MFR of less than 4, the material would be separated into route C, and when it was an MFR of 4 or more, the material would be separated into route D.

[0045] Example 2 Route D and route E of the waste material input section 4 were connected by a tube conveyor, and the recycled resin pellets X' were sent to the waste material input section 4. As a result, a mixture of crushed blue tarp waste and recycled resin pellets X' was sent to the mixer 6, and the same procedure as in Example 1 was carried out to obtain recycled resin pellets Y from route C.

[0046] (Comparative Example 1) The viscosity meter 9, screen changer 7, and gear pump 8 were removed from the recycled resin manufacturing apparatus 1 shown in Figure 1, and an apparatus was used in which the extruder 2 and die 10 were directly connected. As in Example 1, blue tarp waste was added to obtain recycled resin pellets Z. In this apparatus, the gear pump 8 does not control the operation of the adjuster feeding section 5, and no viscosity adjuster is added. There is also no operation control of the diverter-type pneumatic transport valve 11 based on the measurement results of the viscosity meter 9, so all of the granules formed by the granulation unit 3 are discharged from route C.

[0047] The recycled resin pellets X obtained in Example 1, the recycled resin pellets Y obtained in Example 2, and the recycled resin pellets Z obtained in Comparative Example 1 were each made of high-density polyethylene (density: 0.949 g / cm 3 The mixture was mixed at a ratio of 40% by weight with a cellulose ester (MFR: 0.8g / 10min) and fed into an extruder set at 220°C. It was then formed into a tubular film using a round die, which was then slit into tape and stretched on a hot plate to produce a flat yarn (fineness 1,000dt, tape width 3mm).

[0048] The flat yarns obtained using the recycled resin pellets X of Example 1 and the recycled resin pellets Y of Example 2 had sufficient strength properties and could be woven into fabrics. On the other hand, when the recycled resin pellets Z of Comparative Example 1 were used, the film was difficult to stabilize in a tubular shape and the yarn was prone to breakage during the stretching process, making it difficult to obtain a flat yarn. [Explanation of symbols]

[0049] 1 Recycled resin manufacturing equipment 2. Extruder 3 Granulation unit 4 Waste material input section 5 Adjustment material input section 6. Mixer 7 Screen Changer 8 Gear Pump 9 Viscosity measuring instruments 10 dice 11. Diverter

Claims

1. A recycled resin manufacturing apparatus for molding waste resin to obtain granular recycled resin pellets, an extruder that melts and kneads the waste resin; a viscosity measuring device for measuring the viscosity of the molten waste resin; a granulation unit for converting the waste resin whose viscosity has been measured into solid granules; a sorting mechanism that sorts the granular material into standard pellets that are within a predetermined viscosity range and non-standard pellets that are outside the predetermined viscosity range based on measurement information from the viscosity measuring device, Further, a waste material input section for inputting waste resin into the extruder; a viscosity adjusting material input unit for inputting a viscosity adjusting material for adjusting the viscosity of the waste resin; The extruder is provided with a gear pump that discharges a constant amount of molten waste resin, the adjusting material input unit has a feeder that can adjust the supply amount of the viscosity adjusting material, The mixture of the waste resin and the viscosity adjuster can be adjusted to have a viscosity within a certain range based on the viscosity at the extrusion temperature of the extruder. A recycled resin manufacturing device characterized by:

2. A recycled resin manufacturing apparatus as described in Claim 1, which is provided with a re-injection path for re-injecting non-standard pellets separated by the separation mechanism into the waste material feeding section as waste resin.

3. A recycled resin manufacturing apparatus as described in claim 1 or 2, which adjusts the supply amount of the viscosity adjusting material based on rotation information of the gear pump.

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