KR101298068B1 - Apparatus of recycling for polymer - Google Patents

Abstract

PURPOSE: An apparatus for recycling collected waste polymer is provided to save a large amount of energy and rapidly recycle waste polymer without an additional apparatus. CONSTITUTION: An extruder (20) comprises a mixed area (II) in which inert gas is injected and mixed with molten resin in order to maximize a surface area for removing impurities and a pressure reducing and degassing section (III) which is connected to the mixed area and removes impurities at sub atmospheric pressure. A porous plate part (250) equipped with multiple holes in which the molten resin mixed with the inert gas passes to the pressure reducing and degassing section on transfer in the part connected to the pressure reducing and degassing section at the mixed area. [Reference numerals] (AA) Inserting flakes (f); (BB) Heating a heater; (CC) Inserting nitrogen; (DD) Filter; (EE) Gear pump

Description

Apparatus for recycling recovered waste polymer {APPARATUS OF RECYCLING FOR POLYMER}

The present invention relates to an apparatus for recycling waste polyethylene terephthalate (PET) recovered after being used in beverage containers, food containers, etc., including bottled water,

More specifically, the removal of impurities including moisture for high quality can be carried out with the extrusion of the resin, while simplifying the recycling process.

During the extrusion process, an inert gas is added and mixed with the molten resin, and then foamed in the decompression zone while passing through the porous plate portion before transporting into the decompression and degassing zone to maximize the surface area, and then melted through the screw under reduced pressure in the decompression and degassing zone. As the resin is transferred, the first gear formed on the first screw, the second gear formed around the first screw and engaged with the rotating and revolving gears, and the inner gear formed on the cylinder are engaged and melted in the gear gap. Resin is rolled to form a thin film film to expand the surface area and by each of these gear engagements to propose an extruder that is continuously or repeatedly rolled and extended thousands of times to facilitate or enable the removal of impurities,

Finally, it relates to an apparatus for recycling recovered waste polymers that does not require predrying for water removal and raises the degree of polymerization of the polycondensation polymer to enable high quality polymer molding suitable for food containers.

PET (PTE) materials are polymer resins that are widely used for a wide range of applications, especially in beverage containers or bottles, and as food packaging containers.

Polycondensation polymers represented by such PET (PET, polyethylene terephthalate) resin has the characteristics of excellent heat resistance, weather resistance, mechanical properties, transparency and the like, the use area is increasing recently.

On the other hand, as environmental problems arise, recycling of many materials, especially plastics, is being demanded.In order to meet these social demands, recycling of PET containers used for beverage containers, bottles, and food packaging containers is in progress.

Moreover, in the case of recycled PET material, recycling for the manufacture of a PET container which can be applied in the same manner as the PET before use even if recycled is preferable, and it is also preferable that the recycled resin can be suitably used for food. And the impurity is strictly limited for this application.

Therefore, discussions on the recycling apparatus or method of the PET material which can remove impurities to ensure stability during recycling are in full swing.

The recycling process of the PET material proceeds to collecting and melting the used PET, and then removing impurities from the molten resin and regenerating the resin into a reusable resin. It can be divided into treatment processes.

It is an object of the present invention to provide a recycling apparatus for obtaining a high quality polymer suitable for a food container while efficiently removing impurities such as moisture, which is an impediment to the production of high quality polymer in the recovered waste polymer. It is done.

Back to the recycling process of PET material,

The pretreatment process is a step of preparing to the state before the collection and melting of the used PET material usually means a process of collecting the used PET material, then crushed into small flakes, washed and dried.

The flakes that have been pretreated are melted in the main treatment, extruded (degassed), and extruded.

In particular, the flakes that have been pretreated should be sufficiently dried before the main treatment.

Due to the hygroscopic properties, polyester flakes that have undergone pretreatment must be dried because they combine moisture during storage and transportation.They must be dried in a dryer at a temperature of 160 ° C to 180 ° C to remove moisture and the drying time is approximately 6 hours. More residence time is required.

The polyester flakes absorb moisture due to the hygroscopic property, so that the moisture content is 1% by weight. When the flakes are introduced into the extruder for the main treatment process, hydrolysis may occur, which may cause a large viscosity loss.

Therefore, it is usually required to go through the pre-drying process before the addition to the extruder through which the drying to make the water content of the flakes up to 0.01% by weight. Moreover, predrying is important because it leads to an increase in viscosity rather than a decrease in the intrinsic viscosity (IV) of the polymer in the next step of the process.

Next, referring to the main treatment process or the apparatus used in the main treatment process proposed in relation to the main treatment process,

Patent No. 10-0866356 (2008.10.27) Recycling method of polycondensation polymer recovered product, Patent No. 10-2010-0058572 (2010.06.03) Degassing extruder for degassing the polymer material, and the polymer using a degassing extruder And a method of degassing a syrup composed of a solvent and / or a monomer.

Patent No. 10-0866356 discloses the recovered product of the polycondensation polymer in a molten state to a polymerizer having a porous plate, discharged from the hole of the porous plate, and then falls along the support, under the reduced pressure or under a reduced pressure inert gas atmosphere. It relates to a method for recycling a polycondensation polymer recovered product comprising the step of increasing the degree of polymerization of the polycondensation polymer,

Published patent application 10-2010-0058572 discloses a degassing extruder for degassing a polymeric material comprising an extruder cylinder having one or more rotationally driven extruder screws.

However, in the case of Patent No. 10-0866356, the impurity removal process is fundamentally different from the invention described below, and furthermore, there is a problem in that an extruder for extruding a resin from which impurities are removed must be separately provided.

Korean Patent Laid-Open Publication No. 10-2010-0058572 has a degassing zone by increasing the diameter at a specific position of the extruder barrel, there is a problem that there is a limit in the smooth removal of impurities only by forming a degassing zone by changing the diameter.

Moreover, for fibers and films the intrinsic viscosity (IV) of the resin should generally be between 0.6 and 0.75 dl / g, but higher values are required for forming containers or tires and materials.

In addition, higher intrinsic viscosities, such as 0.75 dl / g or more, are intended to be achieved through the polycondensation process of the dissolved pets disclosed in the prior art mentioned above, but there is a limit to increasing the viscosity with only the devices or methods disclosed in the prior art mentioned. In addition, there is a limitation that predrying must be preceded by the main treatment process.

Therefore, the present invention is designed to solve the problems of the above-described prior art in the main processing process or to overcome the limitations,

For the purpose of providing a recycled waste PET material, that is, a device that can save as much energy and recycle as quickly as possible without additional equipment in recycling waste polymers, PET products produced through this recycling process have high viscosity. In particular, it is an object to provide a device for recycling waste polymers to high quality recycled polymers by having a viscosity comparable to that of existing PET materials to be recycled.

Moreover, compared to the existing recycling process, the equipment required for the process or the process is simplified, and the recycled waste polymer can be recycled to increase the degree of polymerization of the polycondensation polymer and to form a high quality polymer suitable for food containers even if the predrying operation is not essential. It is an object of the present invention to provide an apparatus for doing so.

Apparatus for recycling the waste polymer according to the present invention to achieve the above object,

The extruder is a molten resin is extruded, the impurities are removed in the molten resin in the process of extruding,

The extruder includes a mixing zone in which an inert gas is mixed to mix with the molten resin to maximize the surface area for removing impurities, and a decompression and degassing zone in which impurities are removed at sub-atmospheric pressure, which is formed in connection with the mixing zone. Compartmentalized,

The extruder is made of a screw unit which rotates in one direction in the decompression and degassing zone, and comprises a cylinder in which the screw unit is accommodated,

The screw part is located at the center of the cylinder and includes a first screw having a first gear formed on an outer circumferential surface thereof, and a second screw having two or more second gears positioned around the first screw and engaged with the first gear on an outer circumferential surface thereof. Done by

An inner gear is formed on an inner circumferential surface of the cylinder to engage with the second gear.

The second screw is characterized by extending the surface area of the molten resin while removing the impurities in the molten resin while rotating with the revolution around the first screw.

In addition, the technical region is characterized in that the portion leading to the decompression and degassing zone in the mixing zone is provided with a porous plate portion formed with a plurality of small holes through which the molten resin mixed with the inert gas passes when transported to the decompression and degassing zone.

In addition, the porous plate portion is connected to the first screw is characterized in that it is rotated together with the first screw.

In addition, a space is formed between each of the second screws, and a gear gap between the second screw and the first screw or a gear gap between the second screw and the inside of the cylinder or molten resin from both of these gaps and the molten resin in the space It is characterized in that it is mixed and conveyed back between the gears so that the molten resin is rolled and expanded into a thin film in the gear gap.

According to the recycling apparatus according to the present invention having the above-described configuration,

Impurity removal can be performed together with the extrusion molding in the extruder can be expected to simplify the device compared to the existing devices, it is possible to save energy and have the effect of expecting the speed of the recycling operation.

Furthermore, by mixing with an inert gas and vacuum suction in the extruder, efficient impurity treatment is possible, so that an eco-friendly recycled material can be obtained and the pre-drying process is not required. By increasing the degree of polymerization has the effect that it is possible to produce a high-quality polycondensation polymer.

More specifically, the molten resin mixed with the inert gas is foamed in the depressurization zone by passing through the porous plate portion having a plurality of small holes to maximize the surface area, and the first rotating screw and the rotating and revolving agent The gear gap between the two screws and the gear gap of the second screw gear and the inner tooth cylinder are formed and the respective gears are engaged, through which the molten resin is rolled and formed into a thin film for further surface area expansion. The molten resin from the gap and the yongwoong resin contained in the formed space between the second screw and the second screw are mixed and transferred again to roll-expand the molten resin in each gear gap,

Each gear engagement is continuously and repeatedly performed in the extruder until the molten resin is finally discharged from the depressurization and degassing zones, thereby allowing the molten resin to expand its surface area to a thin film and to efficiently remove impurities. ,

Ultimately, it is expected that 100% of the waste polymer can be used and meet the FDA's approval requirements, resulting in high quality recycled polymer materials.

1 is a schematic diagram illustrating a recycling process incorporating the present invention.
2 shows an extruder device according to the invention.
Figures 3 and 4 are views for the structure of the screw in the depressurization and degassing zone according to the invention.

Hereinafter, an apparatus for recycling the waste polymer according to the present invention will be described in more detail with reference to the accompanying drawings.

FIG. 1 schematically shows a pretreatment process and an extrusion process in a recycling process. As described above, the pretreatment process is made of flakes through collecting and pulverizing waste polymers, that is, PET materials, and proceeds to washing and drying processes. Then, the extrusion process is carried out, in particular, according to the recycling apparatus according to the present invention has a technical feature that does not require the pre-drying process itself, which is essentially required in the existing main treatment process.

Accordingly, the extrusion process of the recycling apparatus of the present invention heat-melts the flakes subjected to the pretreatment without predrying, removes impurities during the extrusion of the molten resin, and the extrusion of the recycled polymer proceeds to form a flat sheet or pellet. The process of extracting polymer for recycling.

Next, the impurity used in the present invention is a generic term for substances that not only lower the viscosity when forming recycled materials but also have a harmful effect on the human body.

Means a variety of harmful substances including water, the above hazardous substances include acetaldehyde, cyclic or linear oligomers, monomers such as dimethyl terephthalic acid (DMT), terephthalic acid (TPA), ethylene glycol (EG) and various additives Etc.,

Hereinafter, in the description of the present invention, it will be referred to collectively as impurities.

In particular, acetaldehyde is a serious harmful substance that changes the taste of water when irradiated with ultraviolet rays and is an essential substance to be removed in the recycling process.

As a result, the recycling apparatus according to the present invention is to obtain a high-quality recycled polymer capable of efficiently removing the above-mentioned impurities in the apparatus to reach the target viscosity.

In addition, the recycling apparatus according to the present invention can be applied to the recycling process of various polymers as well as pets, and it does not mean that only the pets are referred to as a representative of the polymer resin, but only to the PET recycling. Therefore, hereinafter, Petra is intended to be collectively referred to as a polymer rather than a specific material.

Figure 2 schematically shows a recycling apparatus according to the present invention used for the extrusion process,

The recycling apparatus according to the present invention includes a supply hopper 10 into which the flake f for recycling is introduced, and an extruder 20 in which impurities are removed while the flake f provided from the supply hopper is heated, melted and extruded. It is done by

In particular, the flake (f) passing through the feed hopper is injected into the extruder and heated and melted to a molten resin state, the molten resin is extruded while removing impurities in the course of passing through the extruder 20,

The extruder 20 is configured to include a screw portion that is rotated in one direction for the transfer of the molten resin, and a cylinder 230 accommodated in the screw portion,

Depending on the action performed in the extruder, it can be divided into a melting zone (I), a mixing zone (II), a reduced pressure and degassing zone (III), and an improved zone (IV),

The decompression and degassing zones may be divided into a decompression zone (III-1) in which decompression is performed and a degassing zone (III-2) in which degassing is performed.

For reference, the cylinder 230 is provided with an inner gear 235 on the inside for inter-gear engagement with the second screw 220. Hereinafter, the cylinder 230 is referred to as an inner cylinder.

In addition, the screw portion mentioned above also refers to a screw located in the decompression and degassing zone (III), and is distinguished from the screw 200 located in the melting zone (I) and the mixing zone (II).

Next, the improved zone (IV) is a section in which the correct amount is transferred to the die and is not the core of the present invention, and thus detailed description thereof will be omitted.

Next, the melting zone (I) is a section in which the flakes introduced through the feed hopper 10 are heated and melted.

The molten resin passing through the melting zone (I) passes through the mixing zone (II).

The mixing zone (II) is a zone where the molten resin is mixed with the inert gas (N), and the recycling apparatus according to the present invention is characterized in that an inert gas is introduced into the extruder to maximize the surface area for removing impurities. do.

For reference, nitrogen may be considered as the inert gas. In addition to the advantage of lowering the partial pressure of by-products generated during the polycondensation reaction and shifting the equilibrium by inert gas, the molten resin may be used in the extruder. By causing the foaming phenomenon to appear violently, the surface area of the molten resin can be drastically increased to extract impurities and to increase the degree of polymerization. Finally, efficient impurities are removed by inert gas injection.

In addition, the removal of impurities through the action of the inert gas is performed in the decompression and degassing zone (III) formed after the mixing zone (II). The decompression and degassing zone is a section in which the pressure is set below atmospheric pressure.

That is, the surface area of the molten resin is drastically increased in the depressurization and degassing zone (III), thereby increasing the degree of polymerization and expanding and increasing the surface area according to nitrogen injection in the mixing zone, thereby easily removing impurities including moisture. .

As will be described later in particular, the extruder in the present invention is provided with a porous plate portion 250 having a plurality of small holes through-hole 255 in the portion leading from the mixing zone (II) to the decompression and degassing zone (III), inert The molten resin in which the gas is mixed is exposed to the reduced pressure zone (III-1) below atmospheric pressure while passing through the through hole 255 to form a foam, thereby maximizing the surface area and removing impurities.

Next, the temperature for polymerizing the polymer in the extruder is preferably set to near the melting point temperature of the polymer material to be recycled. In the case of PET, the temperature inside the extruder is preferably set to about 285 ° C.

A vacuum pump P is connected to one side of the decompression and degassing zone III, more specifically, the degassing zone III-2, and impurities including moisture degassed from the molten resin through the vacuum pump are transferred to the vacuum pump. Inhaled and discharged.

In particular, the vacuum pump (P) sucks the impurities by vacuum suction and is discharged to the outside.

Next, as described above, the extruder 20 according to the present invention includes a screw unit in which rotation in one direction is performed for resin movement, and an inner tooth cylinder 230 in which the screw is accommodated. 230 is located in the depressurization and degassing zone III.

And the inner diameter of the inner tooth cylinder 230 is preferably formed to extend than the inner diameter of the cylinder 200 in the melting zone (I) and mixing zone (II).

This is one of methods for maximizing the surface area of the molten resin. The molten resin and the inert gas are mixed and foamed in the reduced pressure zone while passing through the porous plate part 250 having a plurality of small holes. This is to increase the volume in the decompression zone (III-1) (increasing the inner diameter and ultimately increase the volume) so that the molten resin can be sufficiently expanded when the foam is foamed and can be more deformed. .

And with respect to the size of the inner diameter of the inner cylinder, it is preferable to form the inner diameter of the cylinder in the mixing zone (II) and the inner diameter of the inner cylinder in the decompression and degassing zone (III) in the range of 1: 1 to 1:10.

Next, the molten resin mixed with the inert gas in the mixing zone (II) passes through the porous plate part 250 located at the portion leading from the mixing zone (II) to the decompression and degassing zone (III), followed by the decompression and degassing zone (III). Flows into.

This is because the molten resin conveyed through the mixing zone (II) passes through the through holes 255, which are a plurality of small holes formed in the porous plate part 250, and is then foamed while being exposed to the reduced pressure zone (III-1) below atmospheric pressure. This is to maximize the surface area and to remove impurities including moisture in the degassing zone (III-2).

In addition, the porous plate part 250 may be fixed to the cylinder 230 and may be installed to be fixed to a screw part, that is, the first screw 210.

Next, the structure of the screw and the inner cylinder 230 located in the decompression and degassing zone III will be described in more detail.

2 to 4, the screw portion is located in the center of the cylinder 230 (hereinafter referred to as the first screw 210) and the main screw while a plurality of the main screw is located along the circumference of the outer peripheral surface It includes a planetary screw (hereinafter referred to as a second screw 220) that is engaged with the main screw during rotation and rotation and rotation together.

That is, the first gear 215 is formed on the outer circumferential surface of the first screw 210, the inner gear 235 is formed on the inner side of the inner tooth cylinder 230, and the outer circumferential surface of the second screw 220 The second gear 225 is formed.

The second gear 225 meshes with the first gear 215 on one side and the inner gear 235 on the other side, and the second screw rotates while the first screw 210 rotates. In this case, the first screw is idled around.

Therefore, the molten resin foamed while passing through the through-holes 255, which are a plurality of small holes formed in the porous plate part 250, maximizes the surface area and then removes impurities.

In the gear gap between the second screw 220 and the first screw 210 or in the gear gap of the second screw 220 and the inner cylinder 230 or both, the respective gears are engaged, which causes the molten resin to roll and become thin. The surface area is extended to the membrane to allow easy removal of impurities afterwards (for reference, although the term thin film is used, the term film itself is meant to be a thin layer, which may be collectively referred to as a film, and the present invention provides such a film. Aim to form as thin as possible to expand the surface area).

In addition, as shown in the figure, each of the second screws is not positioned to be engaged with each other outside the first screw, it is preferable to provide a space (S) between each of the second screw.

By providing the space S, each of the gears described above is engaged and the molten resin is rolled and thinned in the gear gap (the gear gap between the second screw and the first screw, and the gear gap between the second screw and the inner tooth cylinder). After the surface area is extended to the membrane, the molten resin from the gap between the gears is mixed with the molten resin located in the space S, and then each gear is engaged again to roll the molten resin to form a thin film, through which This is to expand more.

In addition, the molten resin having an extended surface area is transferred to the gaps between the gears again, and the above-described operation is continuously repeated, thereby ultimately maximizing the surface area to easily remove impurities. That is, this process repeats the engagement of each gear thousands of times by screw rotation, which eventually makes it easy to remove impurities in the molten resin.

In addition, the clearance between the gears is 0.05 mm to 3 mm, and it is preferable that the melt resin is an optimal condition for making a thin film by expanding the surface area due to the engagement between the gears and the gear clearance.

Next, the decompression and degassing zone (III) is followed by the improvement zone (IV), which is a section for feeding and supplying the correct amount, and at the end of the cylinder, a filtration device, a viscometer (V), a gear pump, and a die are sequentially located. The recycled polymer is then extruded into a flat sheet S (or extruded into pellets, depending on the device installed).

In the present invention, the viscosity is adjusted by controlling the pressure valve installed in the vacuum pump line so as to change the decompression degree in accordance with the viscosity measured through the viscometer (V).

And the extruded sheet (S) is made of a container to be applied in a vacuum molding machine, thereby completing a recycled food container.

As a result, an apparatus for recycling the recovered waste polymer according to the present invention,

In the process of extruding the molten resin for recycling and mixing with an inert gas extruder, it is characterized in that to increase the degree of polymerization by removing impurities,

In particular, the surface area is maximized by foaming in the depressurization zone through the porous plate portion 250 having a plurality of small holes before the transfer to the decompression and degassing zone (III). The surface of the molten resin is expanded to a thin film by the second screw and the inner cylinder, thereby easily removing impurities including water.

In the above description of the present invention, the "apparatus for recycling recycled waste polymers" having a specific shape and structure has been described with reference to the accompanying drawings. However, the present invention is well known to those skilled in the art without changing the claims described below. Various modifications and variations are possible, and the variations and modifications should be construed as falling within the protection scope of the present invention.

Description of the Related Art [0002]
10: feed hopper 20: extruder
210: first screw 220: second screw 230: inner cylinder
215; First gear 225; Second gear 235: inner gear
250: porous plate portion 255: through hole
I: melting zone II: mixing zone III: decompression and degassing zone
S: space P: vacuum pump

Claims (6)

The extruder is a molten resin is extruded, the impurities are removed in the molten resin in the process of extruding,
The extruder includes a mixing zone in which an inert gas is injected to mix with the molten resin to maximize the surface area for removing impurities, and a pressure reduction and degassing zone in which impurities are removed at sub-atmospheric pressure, which is formed in connection with the mixing zone. Compartmentalized,
Recycling the recovered waste polymer, characterized in that the portion leading to the decompression and degassing zone in the mixing zone is provided with a porous plate portion having a plurality of holes through which the molten resin mixed with the inert gas passes to the decompression and degassing zone. Device for. The method of claim 1,
The extruder is made of a screw portion that is rotated in one direction in the decompression and degassing zone, and comprises an inner cylinder in which the screw portion is accommodated,
The screw part is located at the center of the inner cylinder, and includes a first screw having a first gear formed on an outer circumferential surface thereof, and two or more positioned around the first screw and engaged with an inner gear of the inner gear of the inner gear and the first gear on an outer circumferential surface thereof. It comprises a second screw formed gear,
And the second screw rotates with the idler around the first screw to expand the surface area to the molten resin film and to remove impurities in the molten resin. 3. The method of claim 2,
A space is formed between each of the second screws to form a gap between the second screw and the first screw, or a gear gap between the second screw and the inner cylinder or a film from both, and the molten resin in the space. Is mixed and again formed into a film by said gear gap. 3. The method of claim 2,
And said porous plate portion is connected to said first screw and rotates together. 5. The method according to any one of claims 1 to 4,
The vacuum pump is connected to the decompression and degassing zone,
And an exhaust of the impurities extracted from the molten resin through the vacuum pump. 5. The method according to any one of claims 1 to 4,
The extruder is provided with a viscometer,
And adjusting the decompression degree in the depressurization and degassing zones to maintain the target viscosity of the viscosity measured by the viscometer.

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