JP2001145920A - Method and apparatus for recovering resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for recovering a resin which can obtain a quality recycled resin which can be used as a molding material equivalent to a virgin resin and an apparatus for the method. SOLUTION: In a method for recovering a resin, the recovered resin is supplied together with a polishing/cooling material and polished so that foreign materials adherent to the surface of the resin are peeled off and separated by a separator. In a polishing apparatus, cylinders fitted with rotary shafts on which impact pins and screw flights are arranged alternately are connected horizontally in parallel. A polishing apparatus is constituted of a vertical cylindrical container and a rotary disk fitted with the impact pins which is arranged in the bottom part of the container through a clearance between it and the bottom part of the side of the container.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for removing foreign matters on the surface of a collected resin when the resin product is collected, reprocessed, and made into a recyclable resin. More specifically, the present invention collects resin products, regenerates them, removes foreign substances on the resin surface when making the resin recyclable, and as a highly purified resin, can be used again for similar applications. TECHNICAL FIELD The present invention relates to a resin recovery method and a device capable of recovering a recycled resin material.

[0002]

2. Description of the Related Art In general, resin products formed by molding resin molding materials such as various synthetic resins are used in a large number of types for a wide range of applications in accordance with diversification of daily life. However, at present, the following various problems have been raised regarding treatment after use in such resin products.

[0003] Many of the resin molding materials constituting resin products have excellent characteristics such as excellent water resistance, weather resistance, and decay resistance. However, incineration of resin products by incineration incinerators generates a large amount of toxic gas and smoke, which is unfavorable for the social environment, and the resin melted during incineration adheres to the furnace itself. There is a problem that may damage the On the other hand, burying in the ground to avoid the problem of incineration is considered to also contribute to environmental destruction because the resin remains without decay for a long period of time. Further, such resin molding materials tend to be depleted year by year in terms of resources, and there is a strong demand for reusing, instead of discarding used resin products.

[0004] However, the recovered resin product contains adhering dirt, foreign substances other than the resin such as labels and seals, coating films and plating films, and denatured and deteriorated layers of the resin material itself. There is a problem that these foreign substances are mixed and contaminated to significantly impair the properties of the recycled resin. Therefore, at present, it is almost impossible to reuse the recovered resin as it is as a raw material for similar uses. As described above, the coating film or the plating film formed on the surface of the resin product is relatively thin and has a strong adhesive force, so it cannot be easily peeled off from the resin, and a known mechanical peeling,
The use of sorting means is likely to cause various undesirable obstacles. For example, when using a crushing means such as a ball mill to separate and separate them, if crushing is continued until the coating film etc. can be separated, the coating film to be peeled is melted due to frictional heat generated at the time of crushing. However, it has a drawback that it cannot be peeled off. Further, as another means, a method of dissolving the coating film on the resin surface with a solvent and performing a separation treatment is also considered, but the processing apparatus itself is increased in size, which is not preferable in terms of economy, and
There are also many problems with recycling or disposal of used solvents.

As another means for removing the coating film and the plating film, there has been proposed a so-called blasting method in which a resin surface is polished with sand or a metal abrasive. However, in such a blasting process using a known abrasive, there is a problem that the blasting material is eroded into the resin, is mixed into the resin as new foreign substances without being separated, and contaminates the resin. It is a problem to adopt as technology.

[0006]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned problems and, when collecting and regenerating a resin product to make it a recyclable resin, removes foreign substances on the surface of the recovered resin and highly purifies it. It is an object of the present invention to provide a resin recovery method and a device capable of recovering a recycled resin material that can be used again for the same purpose as a recycled resin.

[0007]

SUMMARY OF THE INVENTION The present invention relates to a method for recovering a resin product, regenerating the resin product, and making the resin recyclable, at least one selected from the group consisting of dry ice pellets, dry ice crushed products and ice blocks. As a polishing and cooling material, together with the recovered resin consisting of the recovered resin product or a crushed product thereof, is supplied to a polishing apparatus, and is polished while cooling the recovered resin, thereby removing foreign matter on the resin surface, The present invention relates to a method for recovering a resin, comprising separating polishing dust containing a resin and foreign matter by a separation device separately installed in a downstream side. The polishing apparatus is a polishing apparatus having a container in which one or more cylinders are horizontally connected in parallel and a rotating shaft provided in the container. The container has a supply port at one end and a discharge port at the other end. It has an outlet, a rotation axis is arranged at the center of the cylindrical portion of the container, and a plurality of sets of impact pins or impact plates and screw flights are alternately arranged on the rotation axis. Is preferred. Further, the polishing apparatus is a polishing apparatus composed of a vertical cylindrical container and a rotating disk having a plurality of impact pins or impact plates disposed at the bottom thereof, and the rotating disk is arranged with a gap between the bottom of the container side surface and a gap. Preferably, the rotating disk has a structure in which the rotating disk is externally rotated from the upper or lower part of the container via a rotating shaft.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be specifically described below, but the present invention is not limited to these embodiments.
Further, in the following description, expressions for terms and the like indicate preferable examples of the present invention, and do not limit the meaning and technical scope of the terms of the present invention.

The resin that can be recovered by the resin recovery method of the present invention may be any resin as long as it is used for home appliances, office automation, communication equipment, and the like. Examples of the type of resin include polyolefin resins such as polyethylene, polypropylene and copolymers thereof, polystyrene, rubber-modified polystyrene, acrylonitrile-butadiene-styrene copolymer (ABS resin), and acrylonitrile-styrene copolymer (AS). Resin), styrene
Styrene polymers such as methyl methacrylate copolymer, polyester resins such as polybutylene terephthalate, polyethylene terephthalate, polyethylene naphthalate, polycarbonate (PC) resin, polysulfone resin, polyphenylene ether (PPE) resin, polypropylene-based polyolefin resin, vinyl chloride Resin, vinylidene chloride resin, halogen-containing polymer such as chlorinated polyethylene, polyamide resin such as 6 nylon, 6,6 nylon, polyether sulfone resin, polyaryl sulfone resin, polyamide imide resin, polyester, polyamide, polyurethane And polyolefin-based and polystyrene-based thermoplastic elastomers. Further, various polymer blends or polymer alloys composed of these thermoplastic resins, for example,
PC / ABS alloy, PC / PS alloy, modified PPE,
A PBT / ABS alloy or the like can be used without any problem as long as it is a product made of the same alloy.

The "resin product" used in the present invention is a general term for all resin products obtained by molding a resin molding material into a required shape using a mold, a die, and the like. For example, any method such as molding and forming may be used. Examples of the resin product include molded products such as television and electric refrigerator housings and OA equipment housings, parts and members, resin fragments as crushed products thereof, and resin powder as crushed products thereof. And the like, including all molded resin products and deformed resin products.

It is preferable that the resin product used in the present invention is not mixed with products composed of a plurality of different resins. The reason for this is that, when different resins are mixed, the inherent properties of the resin are significantly impaired. Therefore,
It is desirable to sort only products molded from the same resin type. Further, it is desirable that the color tone of the resin product is selected in advance to only products having the same color tone.
By avoiding mixing products having greatly different color tones, for example, a light light gray color product and a dark dark gray color product, it is easy to adjust the color tone of the obtained recycled resin. The size of the resin product is not particularly limited as long as it can be crushed.

[0012] The resin product used in the present invention may be painted or plated. If painted, the material of the coating film may be any of those commonly used. Further, when plated, the plating material may be any commonly used metal.

The recovered resin used in the resin recovery method of the present invention may be a recovered resin product or a product obtained by previously pulverizing them. The pulverization can be performed using a commercially available pulverizer.As the pulverizer, for example, a hammer mill, a cutter mill, or any other pulverizer that can pulverize a resin product to a predetermined size can be used. Such a thing may be used. When the pulverization treatment is performed, it is preferable to perform the pulverization while cooling by passing air forcibly so that the resin does not melt. After crushing, use a vibrating sieve for 1.0
Fine plastic powder, metal powder, dust and the like having a size of about mm or less may be removed. The size of the recovered resin used in the resin recovery method of the present invention is preferably a maximum length of 1 to 3.
0 mm, more preferably 2 to 20 mm, particularly preferably 3 to 10 mm. If the maximum length is less than 1 mm, the amount of fine powder increases, so that the loss during the separation process increases, and the yield decreases. On the other hand, if it exceeds 30 mm, workability will be reduced. The shape of the resin piece may be any shape such as a spherical shape, a flake shape, a block shape, a powder shape, and a pellet shape as long as there is no problem in handling properties.

[0014] In the resin recovery method of the present invention, the recovered resin comprising the recovered resin product or a crushed product thereof is formed by removing at least one abrasive / cooling material selected from the group consisting of dry ice pellets, dry ice crushed products, and ice blocks. Together with the polishing equipment, and grind the recovered resin to separate dirt, foreign matter such as paint film and plating film, and degraded layers of the resin itself, which are attached to the resin surface, and separately installed in the downstream. The separation device separates the collected resin from the polishing dust containing the foreign matter and the degraded resin. Hereinafter, “polishing” and “separation” may be collectively referred to as “washing”. Dry ice pellets, crushed dry ice, and at least one selected from the group of ice blocks are used as a coolant to absorb and remove heat generated by rotation inside the polishing apparatus, thereby softening the resin. Melting can be prevented. Furthermore, if dry ice or ice is used as an abrasive, even if it digs into the recovered resin, it will not remain as a new foreign substance due to sublimation or melting, resulting in a highly purified recycled resin. It becomes possible.

The polishing apparatus of the present invention may be any of a continuous processing system and a batch processing system, and can be appropriately employed. Examples of the polishing apparatus of the present invention are shown in FIGS.

1 and 2 show an example of a continuous polishing apparatus according to the present invention. The polishing apparatus 10 shown in FIGS. 1 and 2 has a supply port 1 at one end and a discharge port 2 at the other end of a container 3 in which two cylinders are connected horizontally in parallel. Rotation shafts 4 and 4 'are provided at the centers of the respective cylindrical portions.
The container of the present invention has a shape in which one or more cylinders are horizontally connected in parallel, and may have a shape in which one or more cylinders having a flat surface in one part are horizontally connected in parallel, as shown in FIG. A cylinder that does not include a plane may be used. However, when a plane portion is included as in the example of FIG. 1, the structure is simple, the inside is not easily filled with resin, heat generation due to excessive friction with the container wall surface can be prevented, and softening and melting of the resin can be suppressed. It is possible and preferable.
Although FIG. 1 shows an example of two axes, the rotation axis does not necessarily have to be two axes, and may be a single axis or two or more axes. However, with a single shaft, the polishing effect is small, and with three or more shafts, the structure is complicated and the equipment cost is high.

The plurality of impact pins 6 or impact plates arranged on the rotating shaft shown in FIGS.
It has a function, and a plurality of sets of screw flights 5 having a material feeding (transporting) function are alternately arranged. Because of the above-described structure, the polishing apparatus shown in FIGS. 1 and 2 can increase the polishing time while maintaining the feed function (piston flow property) in the apparatus, and exhibit an excellent polishing effect. It is possible.

As the shape of the impact pin 6, any of a prism such as a triangular prism and a quadratic prism, a cylinder, and the like can be used, but it is preferable to use a prism having an edge rather than a cylinder because the polishing ability is large. When using a shock plate (not shown),
The impact plate can be provided with a feeding function by being slightly inclined with respect to the axis. Further, by combining an impact plate inclined in the direction of the supply port 1 or the direction of the discharge port 2, the mixing effect of the impact plates can be enhanced, and the impact / polishing effect can be improved. The length of one impact pin 6 or impact plate does not need to be uniform, and may be arranged and installed so as not to apply an excessive offset load to the rotating shaft. The preferred length is
For the screw diameter D provided on the rotating shaft and the rotating shaft diameter d,
1/6 to 1/2 of (Dd), more preferably 1/4
１ ／. If it is less than 1/6, the mixing and polishing ability is small, and it is difficult to achieve sufficient polishing.

The screw flight 5 has a function of efficiently sending the polishing material from the supply port 1 to the discharge port 2. The axial length (A, A ', A "...) Of the screw flight portion (feed portion) 5 and the portion where a plurality of impact pins 6 or impact plates are installed (mixing (impact / polishing) portion) The axial lengths (B, B ', B "...) Can be freely and alternately combined. However, the mixing (impact / polishing) function is very small in the screw flight section,
On the other hand, since the impact pin or the impact plate has almost no feedability, the axial length l [(A, A ', A "...) Or (B, B') ,
B ″ ...)] is 1 / D, preferably 0.5 to 4, more preferably 1 to 3, with respect to the screw diameter D provided on the rotating shaft. In the case of, the screw feeding ability cannot be sufficiently exhibited, while in the case of a combination exceeding 4, the length of the entire apparatus becomes long, which is not economical.

As the flight pitch C of the screw,
Although it is necessary to select in consideration of the rotation speed range of the rotating shaft, since a relatively high-speed rotation is required for the purpose of the present invention, 1 is selected.
When the pitch is represented by a screw diameter D provided on the rotating shaft, it is preferably 0.3 to 1.5 D, more preferably 0.4 to 1.5 D.
1.0D, particularly preferably 0.4 to 0.8D. If the flight pitch C is less than 0.3D, the interval between flights is small, the screw and the resin rotate together, and the feeding capacity is reduced, and the resin clogged between the flights sometimes melts, making it impossible to continue operation. On the other hand, if the flight pitch is 1.
If it exceeds 5D, the feeding efficiency of the screw is reduced, which is not efficient. The material feeding ability by screw is large,
When the residence time of the material in the mixing section (impact / polishing section) provided with the impact pin 6 or the impact plate is insufficient, it is also possible to cut off a part of the flight to make the screw flight discontinuous and adjust. is there.

The rotation speed of the rotating shaft of the polishing apparatus shown in FIGS.
The preferred range varies depending on the size of the apparatus, the type of the target resin, and the desired degree of cleaning, and is not particularly limited, and can be operated at any rotational speed. Generally, the linear velocity at the tip of the impact pin is 0.5 to 50 m
/ Sec is preferable. Linear velocity 0.5m
If it is less than / sec, a sufficient polishing effect cannot be obtained even if the processing time is prolonged. On the other hand, 50m / se
When c exceeds c, heat generation is large, the resin is easily softened and melted, a large driving force is required, and the amount of dry ice required for suppressing heat generation increases, which is not economical.

The size of the polishing apparatus shown in FIGS. 1 and 2 can be arbitrarily designed in view of the required processing time for the desired degree of polishing. L is preferably about 5 to 40 times (hereinafter, this numerical value is referred to as “L / D”), and more preferably 8 to 30. If the L / D is less than 5, the feeding mechanism and the polishing mechanism cannot be sufficiently separated, and a short path of the resin material that is not sufficiently polished occurs. Deterioration of resin quality occurs. On the other hand, when the L / D exceeds 40, the piston flowability of the resin in the apparatus increases, and highly purified recycled resin without the risk of a short path can be recovered. Therefore, it is extremely difficult to increase the strength of the rotating shaft, to devise a method of supporting the rotating shaft, and to prevent contact between the screw blades, the impact pins, and the like and the inner wall of the container.

The method for polishing the recovered resin using the polishing apparatus shown in FIGS. 1 and 2 includes dry ice pellets,
At least one selected from the group consisting of a crushed dry ice product and an ice block is supplied to the container 3 from the supply port 1 together with the recovered resin as a polishing and cooling material. At this time, the recovered resin and the polishing / cooling material can be quantitatively charged into the container 3 using a feeder having a sealing function such as a rotary valve. With the rotation of the rotating shafts 4 and 4 ′ of the polishing apparatus, the supplied recovered resin and the polishing / cooling material are sent to the screw flight 5 and mixed by the impact pin 6 or the impact plate, and are mixed with the resin and the polishing / cooling material. Due to the mutual impact and frictional force of the resin, dirt adhered to the resin surface, foreign substances such as a coating film and a plating film, and a deteriorated layer of the resin itself are peeled off and polished.

In the present invention, dry ice pellets, crushed dry ice products, and ice blocks are used as polishing and cooling materials. Among them, dry ice pellets are preferred. The size (average diameter) of the polishing and cooling material is preferably about 1 to 20 mm, more preferably 2 to 10 mm, and particularly preferably 3 to 7 mm. If it is less than 1 mm, it is not preferable because it is vaporized before exhibiting a sufficient polishing function. On the other hand, if it exceeds 20 mm, the frequency of contact with the resin per weight decreases, and the polishing effect decreases.

The amount of the polishing / cooling material used depends on the desired degree of cleaning the recycled resin and the number of rotations of the rotating shafts 4 and 4 'of the polishing apparatus, and can be arbitrarily selected from the required heat removal amount. Generally, when the polishing / cooling agent is dry ice, it is preferably about 1 to 200 parts by weight, more preferably 5 to 150 parts by weight, based on 100 parts by weight of the resin. To 5 to 300 parts by weight, more preferably 10 to 300 parts by weight.
２００200 parts by weight. If the amount of the abrasive / coolant used is less than the lower limit of the above range, the cost of the abrasive / coolant will decrease, but the temperature rise of the resin cannot be suppressed, and the desired polishing effect cannot be obtained. On the other hand, when the amount of use exceeds the upper limit of the above range, the temperature rise of the resin can be suppressed, but the cost of polishing and cooling material increases, which is not economical.

When dry ice is used as a polishing / cooling material, the polishing apparatus has a closed structure for efficiently collecting carbon dioxide gas generated by sublimation of dry ice, and the supply port 1 and the discharge port 2 of the polishing apparatus are provided. Equipped with a sealing function such as a rotary valve, the exhaust gas in the gas phase in the container is recovered from the exhaust pipe 7 installed at the upper part of the container 3, compressed, liquefied, and again made into dry ice for circulating use. . When using ice blocks as a polishing and cooling material, a slit (not shown) for discharging water can be provided at the lower portion of the cylindrical portion of the container 3 of the polishing apparatus, and draining can be appropriately performed during the polishing process. .

When the polishing apparatus shown in FIGS. 1 and 2 is used, a space must always be secured in the upper part of the container 3 and the container must not be filled with materials (resin and polishing / cooling material). When the material is charged until the container is filled, the flow space of the resin particles is lost, the resin is melted, the power load for rotating the rotating shafts 4, 4 'becomes excessive, and the operation becomes impossible. The standard container filling rate for the steady operation is preferably in a range from the extent that the center of the rotating shaft is visible to the extent that the upper end of the screw blade is partially visible.

Next, FIGS. 3 and 4 show an example of the batch type polishing apparatus of the present invention. The polishing apparatus 20 shown in FIGS. 3 and 4 is composed of a vertical cylindrical container 12 and a rotating disk 13 on the bottom of which a plurality of impact pins 14 or impact plates are arranged. It is arranged with a gap 21 therebetween. And, although not shown,
The rotating disk 13 is configured to be rotated from the outside from the upper or lower part of the container via the rotating shaft 15. The upper part of the vertical cylindrical container 12 is provided with a material inlet 11 and the lower part is provided with a discharge port 18. The discharge port 18 is provided with a piston-type valve 19. The wall forms a smooth surface. The container 12 has a sealing structure of the inlet 11 for the resin and the polishing / cooling material, and an exhaust pipe 16 is mounted on the upper portion of the container 12 to collect carbon dioxide gas generated when dry ice is used as the polishing / cooling material. You can also.

The lower portion of the container 12 has a smaller inner diameter than the upper portion, and has a structure in which a flange 22 is provided on the outside. A gap 21 between the flange 22 and the outside of the rotating disk 13
Are close through. Although not shown, the gap 21
, The sealing gas is blown (purged) from the outside to the inside of the container. The distance of the gap 21 is not particularly limited as long as the resin gas can be blown (purged) from the outside of the container into the inside so that the resin fine powder generated by polishing during the polishing process does not enter the gap 21. May be something. As the sealing gas injected for purging from the gap 21, air or the exhaust pipe 1
The carbon dioxide gas recovered through 6 can be used.

The shape of the impact pin 14 is the same as that of the above-mentioned continuous polishing apparatus, and preferably has a prismatic structure having an edge.
The size and length of the impact pin 14 or the impact plate vary depending on the amount of polishing treatment, the range of the number of rotations of the rotating shaft, and the like, but need not be uniform, and may be disposed symmetrically from the rotating shaft center. .

The preferred range of the number of rotations of the rotating shaft 15 of the polishing apparatus shown in FIGS. 3 and 4 varies depending on the size of the apparatus, the type of the target resin, and the desired cleaning degree, and is not particularly limited. , Can be operated at any rotational speed. Generally, the linear velocity at the tip of the impact pin is 0.5 to
A rotation speed of 50 m / sec is preferable. If the linear velocity is less than 0.5 m / sec, the polishing power is small, and a sufficient polishing effect cannot be obtained even if the processing time is lengthened. On the other hand, 50
If it exceeds m / sec, the heat generation is large, the resin is easily softened and melted, a large driving force is required, and the amount of dry ice required to suppress the heat generation increases, which is not economical.

The size of the polishing apparatus shown in FIGS. 3 and 4 can be arbitrarily designed in accordance with the desired cleaning degree, the amount of recovered resin to be processed per batch, and the processing time.
When polishing, usually the inner diameter of the container is 500 to 1,100 m
m, inner diameter of container bottom 300-800mm, rotating disk diameter 4
00-900mm, height from the rotating disk in the container 400-
800 mm. Within the above range, the contact efficiency between the resin and the polishing / cooling material is good, and the resin can be suitably polished.

As a method of polishing the recovered resin by using the polishing apparatus shown in FIGS. 3 and 4, a polishing and cooling material similar to that of the continuous polishing apparatus is used together with the pulverized recovered resin together with the inlet 11. The container 12 is charged. While blowing the sealing gas through the gap 21 into the container, the rotating shaft 1
5 was rotated from the outside, and the recovered resin and the abrasive / cooling agent which were charged were mixed by the impact pin 14 or the impact plate, and adhered to the resin surface by mutual impact and frictional force with the resin and the abrasive / cooling agent. Dirt, foreign matter such as a coating film and a plating film, and a denatured and deteriorated layer of the resin itself are peeled off.

FIGS. 3 and 4 show the amounts of polishing and cooling materials used.
Can be arbitrarily selected in the same manner as in the continuous polishing apparatus described above. Generally, when the polishing / cooling material is dry ice, for 100 parts by weight of the resin,
Preferably about 1 to 200 parts by weight, more preferably about 5 parts by weight.
The amount is preferably about 5 to 300 parts by weight, more preferably 10 to 200 parts by weight, based on 100 parts by weight of the resin.

When the polishing apparatus shown in FIGS. 3 and 4 is used, the amount of the charged resin per batch is determined by the amount of the recovered resin and the polishing / cooling material. A suitable range is from the degree of hiding to about 30 cm above the tip of the impact pin or impact plate. If the charged amount is less than the above range, it is not economical. On the other hand, when the charged amount exceeds the above range, the mixing performance and the polishing performance are poor, and even if the processing time of one batch is extended, the entire film cannot be uniformly polished, and the resin which does not peel off the coating film and the plating film remains. However, the quality of the obtained resin is reduced. When ice blocks are used as a polishing / cooling material in the polishing apparatus shown in FIGS. 3 and 4, the resin after the polishing treatment contains water, is collected through the outlet 18, and is appropriately separated from water.

By using the polishing apparatus and the polishing / cooling material of the present invention as shown in FIGS. 1 to 4, dirt adhering to the resin surface, foreign substances such as coating films and plating films, and denaturation and deterioration of the resin itself are obtained. The layer and the like are peeled off, and the collected resin and the polishing debris containing foreign matter can be collected from the outlet of the polishing apparatus. In the resin recovery method of the present invention, the mixture of the resin and the polishing dust obtained by the polishing treatment is separated by a separation device (not shown) installed separately in the downstream. As the sorting device, a washing device, a vibrating sieve, an air-flow or water-flow cyclone, a specific gravity separator, a wind classifier, a magnetic separator, a metal separator, and the like can be appropriately combined and used.

The vibrating sieve uses a dynamic sieve, and the resin and the foreign matter are separated by moving the granular material. In the air-flow or water-flow cyclone, the resin and the foreign matter are separated by moving the granular material by the air flow or the water flow. Furthermore, the specific gravity sorter is performed in water using the true density difference between the resin and the foreign matter, and the true density difference between the resin and the foreign matter is preferably 0.3 or more.
Furthermore, the air classifier utilizes the difference between the particle size and the true density between the resin and the foreign matter. Further, the magnetic separation utilizes a magnetic force, and it is preferable to use a magnet having a residual magnetic flux density of 1 Tesla or more, and bring a resin and a foreign substance into contact with the magnetic pole portion of the magnet. Further, the metal separator utilizes eddy current, and is effective for removing metallic foreign substances other than ferromagnetic substances. As the sorting device, preferably, a metal radar MG500 manufactured by Horai Co., Ltd. is used.

In the present invention, the resin and the polishing waste collected from the polishing apparatus are purified by a separating apparatus to become a high-quality recycled resin material with little foreign matter. Then, the obtained recycled resin material can be recycled for the same application as the product member as the raw material.

[0039]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples. In addition, various evaluations were performed as follows.

10 g of the resin obtained by polishing and sorting (washing) the number of foreign substances was sandwiched between stainless steel plates on which a clean film was spread, and heated at 220 ° C. using a hot plate press manufactured by Kansai Roll Co., Ltd.
Pressed at a pressure of 0 kg / cm ² , about 200 mm in size
It was made into a φ film. Film thickness is 0.3-0.7
mm. The film was peeled from the plate, and the number of foreign substances on both sides of the film was visually inspected.

Reference Example 1 (Preparation of Resin Sample) Resin parts of OA equipment collected from the market were manually sorted, parts were separated, and ABS resin members were selected.
This is a commercially available crusher [UG280, manufactured by Horai Co., Ltd.]
Was used to pulverize to a size of 3 to 7 mm to obtain a resin sample (A-1) for washing. In addition, a paper sticker (label) was attached to a part of the above-mentioned members, and dirt adhered to the surface during a long-term use, collection, manual sorting, and component separation processes. Reference Example 2 (Preparation of a resin sample with a coating film) In the same manner as in Reference Example 1, the coated ABS resin member was selected and crushed in the same manner to obtain a resin sample with a coating film for cleaning (B-1).

Example 1 The resin sample (A-1) prepared in Reference Example 1 was fed to the continuous polishing apparatus shown in FIGS. 1 and 2 at a rate of 50 kg / hr.
Dry ice pellets with an average diameter of 3-5 mm
At a rate of hr, a fixed amount was continuously put together, and a polishing treatment was performed. Polishing device, screw outer diameter 80mm, L / D
Was used. A screw and a triangular impact pin were alternately arranged on the rotating shaft so that l / D became 2 to 4 in length, and a part of the screw flight was cut out to adjust the feeding ability. The number of rotations of the rotating shaft is 500 rpm
(The linear velocity of the impact pin was 2.1 m / sec). The resin is collected from the outlet of the polishing device, poured into a separate washing tank with a stirrer, and the polishing debris attached to the resin surface is floated. After that, the polishing debris and paper seal (label pieces) are passed through a wet vibration type sieve. ) And the like were separated and removed, and dried to obtain a recycled resin. Table 1 shows the evaluation results of the obtained recycled resins.

COMPARATIVE EXAMPLE 1 Except that no dry ice pellets were used, all the operations were performed under the same conditions as in Example 1.
The power load became excessive, and the operation of the polishing apparatus became impossible. Table 1 shows the results. Comparative Example 2 After removing the molten resin in the polishing apparatus used in Comparative Example 1 and washing the inside of the apparatus, the rotation speed of the rotating shaft was set to 50 rpm, and all were the same as Example 1 except that dry ice pellets were not used. Performed under the same conditions. Table 1 shows the evaluation results.

Example 2 Polishing treatment was performed using the batch type polishing apparatus shown in FIGS. The container of the polishing apparatus has an upper inner diameter of 800 mm, a lower part narrowed to an inner diameter of 500 mm, and a flange projecting 50 mm outward. The rotating disk disposed at the bottom of the container has an outer diameter of 600 mm,
0 mm was close to the flange at the bottom of the container with a gap of 0.5 mm. The rotating disk has a length of 60 to 10
A combination of a total of 24 0 mm impact pins and arranged symmetrically was used. 20 kg of the same resin sample (A-1) as Example 1, 5 kg of dry ice pellets having an average diameter of 3 to 5 mm, and 3 kg of ice blocks having an average diameter of 30 to 50 mm were put into a batch-type polishing apparatus. At 400 rpm for 15 minutes. Thereafter, the resin was taken out, the foreign matter was separated and removed in the same manner as in Example 1, and dried to obtain a recycled resin. Table 1 shows the evaluation results of the obtained recycled resins.

Comparative Example 3 Except that no dry ice pellets and ice blocks were used,
All were performed under the same conditions as in Example 2. Table 1 shows the evaluation results.

Example 3 Using the same batch-type polishing apparatus as in Example 2, the resin sample (B-1) with a coating film prepared in Reference Example 2 (20 k)
g, dry ice pellets 10k with an average diameter of 3-5 mm
g, 4 kg of an ice block having an average diameter of 30 to 50 mm was charged, and the polishing treatment was performed for 20 minutes at a rotation speed of the rotation shaft of 600 rpm. Thereafter, the resin was taken out, the foreign matter was separated and removed in the same manner as in Example 1, dried, and the remaining coating film was separated by an air classifier to obtain a recycled resin. Table 1 shows the evaluation results of the obtained recycled resins.

Comparative Example 4 Except that no dry ice pellets and ice blocks were used,
All were performed under the same conditions as in Example 3. In the obtained recycled resin, the end of the resin piece was melted, softened and covered so as to wrap around the coating film even with the naked eye, and the coating film was still included. Therefore, the coating film could not be completely peeled off and separated without needing to evaluate the number of foreign substances, and the coating film was poor in cleaning and could not be recycled for the same application as the raw material product member. Table 1 shows the evaluation results.

[0048]

[Table 1]

*: Judgment was made as acceptable if the material could be recycled for the same application as the raw material product, and rejected if not. **; "Innumerable" indicates that it cannot be counted due to the large amount of foreign matter.

As is clear from Table 1, the recycled resin obtained by the recovery method of the present invention had a small amount of foreign substances, and could be recycled for the same application as the product member as the raw material. On the other hand, Comparative Examples 1 to 4 which did not use the polishing / cooling material of the present invention all had a large amount of foreign matters, and were not recyclable.

[0051]

According to the present invention, the recovered resin is softened and melted by using at least one selected from the group consisting of dry ice pellets, crushed dry ice, and ice blocks as a polishing and cooling material. In addition, it is possible to peel off and separate the resin surface foreign matter and the degraded layer of the resin itself, and obtain a high-quality recycled resin material with little foreign matter, and it can be recycled for the same application as the raw material product parts. is there. Further, by using the polishing apparatus of the present invention, the above-mentioned cleaning treatment can be efficiently and economically performed.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view perpendicular to a rotation axis of an example of a polishing apparatus according to the present invention.

FIG. 2 is a schematic sectional view parallel to a rotation axis of an example of the polishing apparatus of the present invention.

FIG. 3 is a schematic longitudinal sectional view of another example of the polishing apparatus of the present invention.

FIG. 4 is a schematic plan view of a rotating disk and a rotating shaft of another example of the polishing apparatus of the present invention.

[Explanation of symbols]

 Reference Signs List 3 container 4, 4 'rotating shaft 5 screw flight 6 impact pin 12 container 13 rotating disk 14 impact pin 15 rotating shaft 21 gap

Claims (3)

[Claims] 1. A method for recovering and recycling a resin product to obtain a recyclable resin, wherein at least one selected from the group consisting of dry ice pellets, dry ice crushed products and ice blocks is used as a polishing / cooling material. A separation device is supplied to a polishing device together with the recovered resin made of the recovered resin product or its crushed product, and the cooled resin is polished while cooling, thereby removing foreign matters on the resin surface, and then separately installed in the downstream. The method for recovering a resin, comprising: separating polishing dust containing the resin and the foreign matter. 2. A polishing apparatus having a container having a shape in which one or more cylinders are connected horizontally in parallel and a polishing apparatus having a rotating shaft provided in the container. The container has a supply port at one end and a discharge port at the other end. An outlet is provided, and a rotating shaft is arranged at the center of the cylindrical portion of the container, and a plurality of sets of impact pins or plates and a plurality of screw flights are alternately arranged on the rotating shaft. Item 4. The polishing apparatus according to Item 1. 3. A polishing apparatus comprising a vertical cylindrical container and a rotating disk having a plurality of impact pins or impact plates disposed at the bottom thereof, wherein the rotating disk is disposed with a gap between the bottom of the container side surface and a gap. 2. The polishing apparatus according to claim 1, wherein the rotating disk has a structure in which the rotating disk is externally rotated from an upper or lower part of the container via a rotating shaft.