KR101278570B1 - Apparatus and method of recycling for polymer - Google Patents

Abstract

PURPOSE: A device and a method for recycling a collected waste polymer are provided to obtain an environment-friendly recycled material by efficiently processing impurities by passing through a process including a vacuum suction and a mixing with an inert gas inside an extruder. CONSTITUTION: A device for recycling a collected waste polymer includes an extruder(20). The extruder comprises a mixing area(II),and a reduced pressure and degassing area(III). The reduced pressure and degassing area is formed by connecting with the mixing area and is a sub atmospheric pressure state. An inert gas is put into the mixing area and is mixing with a molten resin in order to maximizing a surface for eliminating impurities. In the reduced pressure and degassing area, impurities are eliminated. [Reference numerals] (AA) Feed flake; (BB) Heater; (CC) Inject nitrogen; (DD) Filter; (EE) Gear pump

Description

An apparatus for recycling the recovered waste polymer and a recycling method using the apparatus {APPARATUS AND METHOD OF RECYCLING FOR POLYMER}

The present invention relates to an apparatus and method for recycling waste polyethylene terephthalate (PET) recovered after use 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, the inert gas is mixed with the molten resin and foamed while passing through the through-hole of the screw to maximize the surface area, and then the molten resin is transferred by the screw shape under reduced pressure in the decompression and degassing zone to further maximize the surface area. We propose an extruder for extracting impurities to carry out polycondensation and polymerization,

Finally, it relates to an apparatus for recycling the recovered waste polymer which 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.

These, including moisture, are impurity that inhibits the manufacture of high quality polymers in the recovered waste polymer, and the present invention seeks to provide a recycling apparatus and method for obtaining high quality polymers suitable for food containers while efficiently removing impurities. For the purpose of

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.

Polyester flakes that have undergone pretreatment must be dried due to their moisture-absorbing properties because they bind moisture during storage and transportation.They must be heated in a dryer at a temperature of 160 to 180 to remove moisture. I need time.

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) A method for recycling polycondensation polymer recovered product, a degassing extruder for degassing the polymer material, and a 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 a recovered product of a polycondensation polymer in a molten state to a polymerizer having a porous plate, discharges it from a hole in the porous plate, and then drops it along a support under an inert gas atmosphere under reduced pressure or reduced pressure. 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,

PET articles manufactured through this recycling process, with the intention of providing a device and method for the recycling of recovered waste PET materials, ie waste polymers, as much as possible and saving as much energy as possible without additional equipment. It is an object of the present invention to provide an apparatus and a recycling method for recycling waste polymers to high quality recycled polymers by allowing them to have a viscosity comparable to that of existing PET materials to be recycled, in particular high quality.

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 and method for performing the same.

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

It includes an extruder in which the heated and molten resin is extruded, the impurities in the molten resin is removed in the extrusion process,

The extruder is formed in front of the mixing zone, the mixing zone is formed to include a reduced pressure zone and a degassing zone of sub-atmospheric pressure,

In the mixing zone, an inert gas is added to mix with the resin to maximize the surface area for removing impurities,

It is a technical feature that impurities are removed in the degassing zone.

In addition, the extruder according to the present invention is made of a resin movement along the outer circumferential surface is made of a screw portion that is rotated in one direction for the resin movement, and the cylinder containing the screw portion,

The screw portion includes a screw drum positioned in the depressurization zone, and a molten resin flow passage for allowing resin mixed with the inert gas to flow into the screw drum.

The screw drum is formed with a plurality of through holes for discharging the resin transferred into the screw drum through the molten resin flow passage to the outside of the screw drum to maximize the surface area,

As the foamed resin discharged to the outside through the through hole is transferred by a screw shape, the surface area is further maximized to degas the impurities.

In addition, the degassing zone is connected to a vacuum pump,

It is a technical feature that the discharge of impurities degassed from the resin is made through the vacuum pump.

In addition, the extruder according to the present invention is provided with a viscometer, it is characterized in that the reduced pressure in the pressure reduction zone adjustment is made so that the pressure can be changed according to the viscosity measured by the viscometer.

On the other hand to recover the waste polymer according to the present invention to achieve the above object,

After the molten resin for recycling is mixed with an inert gas and the impurities in the molten resin are removed in the extrusion process and the degree of polymerization is increased, the extrusion of the recycled polymer is performed through the extruder.

According to the recycling apparatus and method which concerns on this invention by the above-mentioned structure,

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 of producing a high-quality polycondensation polymer,

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 and 3 show an extruder device according to the invention.
4 shows another embodiment of a screw in a recycling apparatus according to the invention.

Hereinafter, an apparatus and method for recycling waste polymers 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. After the extrusion process, the recycling apparatus according to the present invention has a technical feature that the pre-drying process itself, which is essentially required in the existing main treatment process, is not required.

Accordingly, the extrusion process performed through the recycling apparatus and method 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 the flat sheet or pellet. It refers to the process of extracting polymer for recycling in form.

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.

After all, the recycling apparatus and method according to the present invention is to obtain a high-quality recycled polymer that can efficiently remove the 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.

2 and 3 schematically show a recycling apparatus according to the present invention used for the progress of 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, when the flake (f) passed through the feed hopper is introduced into the extruder is heated and melted into 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 the 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.

First, the improved zone (IV) is a section for feeding and feeding the correct amount, which is not the core of the present invention, so a 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, melted, 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 the by-products generated during the polycondensation reaction and shifting the equilibrium, the molten resin inside the extruder may be advantageously added. The phenomena of foaming can be shown violently, and the surface area of the molten resin can be dramatically increased and the surface improvement state can be improved.

Eventually an inert gas input results in efficient removal of impurities.

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, in the decompression and degassing zone (III), the surface area of the molten resin is dramatically increased and the surface improvement state is improved, thereby increasing the polymerization rate, and the impurities including moisture as the expansion and surface area are increased due to nitrogen injection. It is easy to remove.

In particular, as will be described later, the through-hole 225 or the second through-hole 255 is foamed while allowing the surface area to be maximized while removing impurities.

Furthermore, the molten resin that has passed through the through hole is transferred by a screw shape to be described later to further maximize the surface area to efficiently remove 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.

In addition, 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 a cylinder 230 in which the screw is accommodated.

The screw portion includes a screw 210 located in the melting zone I and the mixing zone II and a screw drum 220 located in the decompression and degassing zone III.

In addition, at the boundary between the mixing zone (II) and the depressurization and degassing zone (III), a molten resin flow path 240 is formed to allow molten resin mixed with the inert gas to flow into the screw drum 220.

The screw drum 220 is formed with a plurality of through holes 225 for discharging the molten resin moved into the screw drum 220 through the molten resin flow path 240 to the outside of the screw drum.

As a result, the molten resin mixed with nitrogen flowing into the screw drum through the molten resin flow passage 240 is discharged out of the screw drum again through the through hole 225 to maximize the surface area, and to reduce the pressure and degassing zone (III). Exposure will result in the removal of impurities, including moisture.

Furthermore, between the screw drum 220 and the molten resin flow path 240 is provided with a connecting member 250 formed with a plurality of second through holes to the outer periphery of the cylinder (see enlarged cross-sectional view of Figure 2),

As the molten resin transferred through the mixing zone (II) passes through the plurality of second through holes (255) formed in the connecting member 250, the surface area is also maximized, and moisture is exposed to the decompression and degassing zone (III). Including impurity removal is made.

Depending on the application of the device may be provided only the second through hole 255 formed in the connecting member 250 without forming the through hole 225 in the screw drum 220,

By forming only the through hole 225 in the screw drum 220 without the connecting member 250, it is possible to maximize the surface area of the molten resin,

In addition, all can be formed as shown in the figure.

Next, the screw drum shape may be designed as shown in FIG. 4, and the molten resin mixed with the inert gas is transferred by the screw drum shape under the reduced pressure and degassing zone (III) to maximize the surface area once more. In addition, the impurity extraction is more efficient than the existing recycling apparatuses.

That is, as shown in FIG. 4, the incision 220c is formed in the blade of the screw, and the molten resin having passed through the through hole 225 or the second through hole 255 is formed through the incision 220c. As it flows through the gaps, the process of thin and long stretching is continuously performed by melt viscosity, maximizing the surface area.

Therefore, the incision width of the incision 220c is preferably wide and the depth of the incision is formed shallow.

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, the method for recycling the recovered waste polymer according to the present invention uses the recycling apparatus described above.

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

In the above description of the present invention, the "apparatus and method for recycling the recovered waste polymer having a specific shape and structure" have been described with reference to the accompanying drawings, but the present invention does not change the claims described below. Various modifications and variations are possible by those skilled in the art, and such 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: screw 220: screw drum 230: cylinder
240: molten resin flow path 225: through hole
250: connecting member 255: second through hole
I: melting zone II: mixing zone III: decompression and degassing zone
P: vacuum pump

Claims (9)

The extruder is a molten resin is extruded, the impurities are removed in the molten resin in the process of extruding,
The extruder is formed in front of the mixing zone and the mixing zone is formed to include a reduced pressure and a degassing zone of sub-atmospheric pressure,
In the mixing zone, an inert gas is added to mix with the molten resin to maximize the surface area for removing impurities,
And removing impurities from the depressurization and degassing zones. The method of claim 1,
The extruder is made of a screw unit that is rotated in one direction for the molten resin movement, and the cylinder containing the screw portion,
The screw unit includes a screw drum positioned in the depressurization and degassing zone, and a molten resin flow path for allowing molten resin mixed with the volatile gas in the mixing zone to flow into the screw drum.
And said screw drum is formed with a plurality of through-holes for discharging molten resin moved into the screw drum through the molten resin flow passage to the outside of the screw drum. The method of claim 1,
The extruder is made of a screw unit that is rotated in one direction for the molten resin movement, and the cylinder containing the screw portion,
The screw portion is formed in the front of the screw drum and the screw drum located in the decompression and degassing zone, and the second through hole is formed so that the molten resin mixed with inert gas in the mixing zone flows into the decompression and degassing zone. Apparatus for recycling the recovered waste polymer, characterized in that it comprises a connecting member. The method of claim 1,
The vacuum pump is connected to the decompression and degassing zone,
And the degassed impurities from the resin are discharged through the vacuum pump. The method of claim 1,
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. 3. The method of claim 2,
And an incision is formed on an outer circumferential surface of the screw portion. In the recycling method of the recovered waste polymer using an extruder,
After mixing the molten resin for recycling with an inert gas to remove impurities in the molten resin during the extrusion process,
And the molten resin flows into the screw drum provided in the extruder and is foamed while passing through the through hole formed in the drum to maximize surface area and remove impurities in the molten resin. In the recycling method of the recovered waste polymer using an extruder,
After mixing the molten resin for recycling with an inert gas to remove impurities in the molten resin during the extrusion process,
In the flow of the molten resin into the screw drum of the extruder, it is foamed while passing through the through hole of the connecting member provided in front of the screw drum to maximize the surface area and to remove impurities in the molten resin, characterized in that the recovered waste polymer Recycling method. 9. The method according to claim 7 or 8,
The molten resin having passed through the through hole is transferred to the screw drum shape to maximize the surface area to remove impurities in the molten resin, characterized in that the recycled waste polymer recycling method.

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