JP2003170428A - Thermoplastic resin pieces - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide thermoplastic resin pieces of which the corners are made round and the surface coating films or the like are removed, to mix them with an unused thermoplastic resin granulated article, and to reutilize them as a thermoplastic resin composition. <P>SOLUTION: A recovered thermoplastic resin product is crushed to form crushed pieces which are, in turn, supplied to a washing device, wherein at least a part of the inner surface of a container 1 and/or the surface of a rotary body 2 is roughened by uneven parts or the like with a depth of 40-2,000 μm, along with water and washed by rotating the rotary body. Water is continuously supplied to the washing device from one or more places and drained so that the water level in the washing device becomes constant to preferably wash the crushed pieces, while keeping the mass ratio of the crushed pieces and water constant. It is more preferable to control the mass ratio of the broken pieces and water in the washing device to 1:0.3-5 to wash the broken pieces while continuously supplying water so that the temperature of the resin in the washing device becomes the softening temperature thereof or lower to discharge the same. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a recovered thermoplastic resin product (hereinafter also referred to as “resin product”).
It is a resin piece for crushing and reusing it, and the foreign material such as coating film, plating film applied on the product, and the attached label, seal, or other dirt has been removed. And a thermoplastic resin piece having a smooth surface. INDUSTRIAL APPLICABILITY The present invention is applicable to home appliances such as televisions and electric refrigerators, or to personal computers, printers and the like.
It can be used in a variety of resin products such as the casing of equipment A and interior / exterior parts of automobiles.

[0002]

2. Description of the Related Art At present, resin products made of various synthetic resins are used in large amounts in a wide range of applications with the diversification of life. However, various problems have been raised as to the treatment of these various resin products after use, as follows.

Most of the synthetic resins have sufficient water resistance, weather resistance and the like, and have excellent features such as corrosion resistance. However, when the resin product is incinerated when it is discarded, a large amount of smoke and harmful gas are generated, which is not preferable from the environmental viewpoint. There is also a problem that the molten resin may adhere to the furnace wall and damage the incinerator itself. On the other hand, when it is buried in the ground, it is not corroded or decomposed and remains as it is for a long period of time, which is also considered to be a cause of environmental damage. Furthermore, the raw material of the synthetic resin itself tends to be depleted year by year, and it is necessary to reuse the used resin product without discarding it.

Therefore, crushing a resin product with a crusher or the like and reusing this resin piece has been studied. In addition, the physical properties of the recovered resin products have deteriorated due to heat history during molding or during use.Therefore, it is possible to mix unused resin with resin pieces to reduce the physical properties after reuse. It is also held down. However, a crushed piece obtained by crushing a resin product with a crusher or the like has many sharp edges, and when used by mixing with an unused resin, it is not easy to uniformly mix the crushed piece with the unused resin. In addition, it is difficult to drop the hopper from the hopper into the barrel during molding, resulting in poor workability.

Further, the recovered resin product may be painted, labeled, or have various stains on it. When mixed with crushed pieces and reused, there is a problem that the appearance and physical properties of the resin product are significantly impaired. Therefore, at present, it is not normally performed to reuse the resin after treating the recovered resin product for the same purpose as it is.

Removal of foreign substances on the surface of resin products has been attempted by mechanical methods or various methods such as separation and removal with a solvent, but all have problems. For example, even if a crushing device such as a ball mill is used to remove a coating film, a label, etc., the resin softens due to the heat generated by the friction of crushing, making it difficult to remove, or the foreign matter once removed reattaches. There's a problem. Also,
There is also a method of dissolving and separating and removing with a solvent, but there is a difficult problem of recycling or discarding the solvent used, and the processing equipment itself becomes complicated and various problems such as not preferable from the economical aspect have.

Further, as another method for removing the coating film, the label, etc., a so-called dry blast treatment has been proposed in which foreign matter on the surface of the resin product is scraped off with an abrasive composed of sand or metal particles. However, in this method, the abrasive may dig into the surface of the resin product and remain as new foreign matter in the resin product. Further, there is a problem that the resin is softened by the heat generated by the friction caused by the abrasive and the foreign matter once removed is reattached.

[0008]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned conventional problems, and when recovering and reusing a resin product, foreign matter such as a coating film and a label is sufficiently removed, Moreover, the object is to provide a thermoplastic resin piece having a smooth surface and easy to reuse.

[0009]

The thermoplastic resin piece of the present invention is derived from crushed pieces of a thermoplastic resin product, has rounded corners, and has no foreign matter attached to the surface. . According to the present invention, a container and a rotating body incorporated in the container are provided, and the container is provided with a resin crushed piece inlet provided at an upper portion of one end edge and a resin crushed piece discharge provided at a lower portion of the other end edge. An outlet, a water supply port, and a drainage port, a drainage channel for adjusting the water level is connected to the drainage port, and the rotating body has a rotating shaft, screw blades provided around the rotating shaft, and a plurality of cleaning plates and A cleaning device having at least one of cleaning pins, wherein at least a part of the inner surface of the container and / or the screw blade, at least one surface of the cleaning plate and the cleaning pin is roughened. Can be used as a thermoplastic resin piece obtained by washing the crushed pieces with water as a medium. Further, it comprises a container and a stirring blade, the container has a resin crushed piece input port and a water supply port provided in the upper part, and a resin crushed piece discharge port and a drain port provided in the lower part, the drain port Uses a cleaning device in which a water level adjusting drainage channel is connected and at least part of the inner surface of the container and / or the surface of the stirring blade is roughened, and the crushed pieces are washed with water as a medium. A thermoplastic resin piece obtained in this way can also be used.

[0010]

EFFECT OF THE INVENTION The thermoplastic resin piece of the present invention has rounded corners, and a coating film applied to a thermoplastic resin product,
Since the plating film and the attached label, seal, or other foreign matter such as stains do not remain, the unused thermoplastic resin granulated product can be easily blended and uniformly mixed. Therefore, it is possible to sufficiently suppress deterioration of the physical properties of the resin product molded by reuse. Also,
If it is a thermoplastic resin piece obtained by washing crushed pieces obtained by crushing a resin product with a specific washing device, it is easy to handle when reused, and the physical properties of the resin product molded by reuse can be reduced. It can be suppressed more reliably. Furthermore, the thermoplastic resin piece of the present invention can be uniformly mixed with an unused thermoplastic resin granulated product, and even though it contains the recovered resin, it has sufficient physical properties. It can be a resin product.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention is described in detail below. [1] A thermoplastic resin product that can be recovered as a crushed piece of thermoplastic resin is not particularly limited, and any thermoplastic resin product molded by various methods such as extrusion molding, compression molding, injection molding, and blow molding can be used. The resin product for the purpose can be used. These resin products may be molded using a molding die, or may be molded using a molding die or the like without using the mold. Specific examples of this resin product include housings for home appliances such as televisions, audio equipment, and electric refrigerators, housings for office automation equipment such as personal computers and printers, and automobiles such as instrument panels and bumpers. In addition to the interior / exterior parts, etc., the parts of these products, and further the damaged parts of these products and parts, etc.

As described above, the type and shape of the resin product are not particularly limited, but it is preferable not to mix products made of a plurality of different resins. The reason is that, in general, when different types of resins are mixed, the original characteristics of the respective resins are significantly impaired, and it is preferable to separate and use the products made of the same type of resin in advance. Further, it is preferable that the color tones are previously sorted by the same or similar products. It is preferable not to mix products having greatly different color tones, such as a light and light gray product and a dark and dark gray product. The color tone of the resin to be reused can be easily adjusted without mixing products having greatly different color tones. The size of the resin product is not particularly limited as long as it can be crushed to an appropriate size by an ordinary device.

Further, the resin product may be painted or plated, and when it is painted, the material of the coating film may be any of those usually used for resin painting. Good. Further, when plated, the material of the plating may be any metal usually used for plating of resin.

Since the thermoplastic resin pieces have rounded corners, they are easy to handle when reused. "Rounded corners"
The term "means that there are almost no sharp corners such as crushed pieces obtained by crushing a resin product with an ordinary crusher such as a crusher, a hammer mill and a cutter mill. More specifically, it means that the corners of the edge between the flat surface and the end surface of the resin piece are rounded. Such resin pieces having rounded corners have excellent handleability in reuse and can be uniformly mixed when mixed with an unused thermoplastic resin granulated product. It is possible to suppress deterioration of quality such as physical properties of a resin product obtained by using.

Further, when the resin product is coated, plated, etc., or has a label, a seal, etc. attached,
On the thermoplastic resin piece, no foreign matter such as paint, plating, label, seal, etc., especially foreign matter having a maximum length exceeding 0.25 mm remains. Furthermore, dirt and the like attached during use hardly remain on the crushed pieces. That is, the thermoplastic resin piece is composed of a resin, blended pigments, dyes and various additives. As described above, since the resin piece does not contain any foreign matter, it is possible to sufficiently suppress the deterioration of the quality of the resin product manufactured by reusing the resin piece.

Regarding the size of the thermoplastic resin piece, the maximum length thereof is 1 to 30 mm, particularly 2 to 20 mm, and further 3 to 10 mm.
Is preferred. Fine resin pieces having a maximum length of less than 1 mm are not preferable because they tend to scatter during handling. On the other hand, when the maximum length exceeds 30 mm, it is not preferable because it is difficult to handle and it is not easy to supply it to a molding machine or the like at the time of reuse. Further, the shape of the resin piece is not particularly limited as long as there is no problem in handleability, but an elongated shape is not preferable, and a circular shape or a rectangular shape having no great difference in dimension in each direction of the plane is preferable. If necessary, when the resin product is crushed, crushed pieces having a maximum length of about 1 mm or less, metal powder, dust and the like can be removed in advance by a vibrating screen or the like.

The types of resin forming the resin product include
Polyolefin resin such as polyethylene, polypropylene and ethylene-propylene copolymer, polystyrene (PS), rubber modified polystyrene and acrylonitrile-butadiene-styrene copolymer (ABS resin), acrylonitrile-styrene copolymer, styrene-methylmethacrylate copolymer Examples thereof include styrene resins such as polymers, polyester resins such as polybutylene terephthalate (PBT), polyethylene terephthalate and polyethylene naphthalate.

Polycarbonate (PC) resin, polysulfone resin, polyethersulfone resin, polyarylsulfone resin, polyphenylene ether (PPE)
Resin, vinyl chloride resin, vinylidene chloride resin, halogen-containing resin such as chlorinated polyethylene, 6 nylon, 6,6
In addition to polyamide-based resins such as nylon and polyamide-imide resins, thermoplastic elastomers such as polyolefin-based, polystyrene-based, polyester-based, polyamide-based, polyurethane-based and the like can be mentioned. Further, various polymer blends or polymer alloys containing these thermoplastic resins, for example, PC / ABS alloy, PC / PS alloy,
Modified PPE, PBT / ABS alloy and the like can be subjected to washing treatment without any problem as long as they are resin products made of the same alloy.

[2] Apparatus and Method for Obtaining Thermoplastic Resin Pieces The method for preparing the thermoplastic resin pieces using the crushed pieces obtained by crushing the resin product is not particularly limited, but the following specific washing is performed. A method of using an apparatus and washing with water as a medium is preferable.

The cleaning device may be of a horizontal type or a vertical type, and may be of a continuous type or a batch type. Also, this cleaning device
Usually, the respective devices for washing, dehydrating and drying the washed resin pieces are provided in combination. Further, if necessary, a vibrating screen, a wind power sorter, a metal detector, etc. may be arranged in combination. As a result, foreign matter such as paint films, labels, and dirt can be removed more reliably,
Can easily be a resin piece with no foreign matter attached,
This resin piece can be reused without any problem in the intended use. Hereinafter, one example of each of the horizontal continuous cleaning apparatus and the batch type cleaning apparatus that can be used for preparing the thermoplastic resin piece of the present invention will be described in detail.

The resin pieces are dried by, after washing, collecting slurry containing foreign matters such as paper seals that did not pass through the slit provided at the drain port, and then, using a vibrating screen with an appropriate opening. Scatter in water and sprinkle with water to separate and remove fragments such as paper seals and dust, and dehydrate with a dehydrator.
It is preferable to carry out. The drying temperature and drying time are not limited, but may be 0.2 to 10 hours at 50 to 100 ° C. Further, by drying under reduced pressure, it is possible to dry at a lower temperature and in a shorter time. Further, if necessary, a foreign matter having a small specific gravity, which could not be removed by water spraying, can be separated and removed by an air classifier or the like.

(1) Horizontal Continuous Cleaning Device FIG. 1 is a schematic view showing a horizontal cross section of the horizontal continuous cleaning device, and FIG. 2 is a schematic view showing a vertical cross section. Container In FIGS. 1 and 2, the container 1 can be formed of a metal such as stainless steel. A crushed piece input port 11 is provided above the one end edge of the container 1, and a crushed piece discharge port 12 is provided below the other end edge. Also, at least one water supply port 13 is usually provided at the upper part of the container 1, and the drainage port 1 is provided at the lower part.
4 is provided, and this drain port 14 has a drainage channel 1 for adjusting the water level.
Five are connected.

A predetermined amount of crushed pieces are continuously charged from the crushed piece input port 11, conveyed in the container 1, and discharged from the crushed piece discharge port 12. At this time, it is preferable that the rate of charging the crushed pieces and the rate of discharging the crushed pieces are approximately the same, and these rates are substantially constant. In addition, the water supplied from the water supply port 13 takes into account the drainage speed from the opening end of the water level adjusting drainage channel 15 connected to the drainage port 14, and the water level adjusting pipe 15
It is preferable to supply at a rate such that the water level set by b is maintained. In this way, by adjusting the rates of charging and discharging the crushed pieces and supplying and discharging water, a fixed amount of crushed pieces and water are always conveyed in the container 1 and discharged.

The water continuously supplied at the time of cleaning acts as a lubricant between the surface of the crushed pieces and the portion roughened by the uneven portions, and the surface of the crushed pieces may be scraped off excessively. Absent. In addition, the cooling action of water suppresses the temperature rise of the shredded pieces and prevents them from softening.At the same time, the removed foreign matter such as paint films and labels is promptly discharged from the washing device to the outside and reattached to the shredded pieces. Is also prevented. Furthermore, water is continuously supplied and discharged so that the water level in the device is kept constant, and the amount of crushed pieces input is kept constant, so that the mass ratio of crushed pieces to water is kept constant during washing. This is preferable because each of the continuously charged crushed pieces can be washed more uniformly.

The amount of water continuously supplied and discharged is controlled so that the mass ratio of crushed pieces to water is 1: 0.3 to 5, and the temperature in the cleaning device is softened by the resin. It is preferable that the temperature is not higher than the temperature. If the amount ratio of water is less than 0.3, the inside of the cleaning device may not be sufficiently cooled, and the temperature may exceed the temperature at which the resin softens, and the crushed pieces may soften and melt, which may prevent cleaning. On the other hand, if the amount ratio of water exceeds 5, crushed pieces will
The frequency of contact with the inner surface of the container and the surface of the rotating body, especially with roughened parts such as irregularities, decreases, and even if they come into contact, sufficient pressing force is not applied to the crushed pieces, coating films, labels, etc. In some cases, the foreign matter cannot be removed sufficiently and efficiently.

A slit, a punching plate, or the like is formed in the drain port 14 provided in the lower portion such as the bottom of the container 1. Further, the water level adjusting drainage channel 15 connected to the drainage port 14 is connected to the drainage port 14 and is slidable in the drainage pipe 15a which is erected on the side of the container 1 and the drainage pipe 15a. It is formed by an inverted U-shaped water level adjusting pipe 15b fitted in the. A sealing O-ring 15c is interposed between the inner peripheral surface of the drainage pipe 15a and the outer peripheral surface of the water level adjusting pipe 15b to keep it watertight. By moving the water level adjusting pipe 15b up and down, The water level can be adjusted to maintain a predetermined water level.

The open end of the water level adjusting pipe 15b is opened to the atmosphere so that the water level in the container 1 becomes substantially equal to the height of the open end of the water level adjusting pipe 15b. As a result, the water level is maintained constant even when the amount of water supplied changes, and excess water is discharged from the open end of the water level adjusting pipe 15b. The discharged water may be stored in a water storage tank, pumped up by a pump, filtered with a filter to remove foreign matters such as dust, and circulated for reuse.

On the rotary shaft 21 of the rotating body, screw blades 22 for conveying the crushed pieces from the input port to the discharge port in the length direction thereof, and scraping off the foreign matter on the surface while giving an impact to the crushed pieces, or Cleaning plates 23 and cleaning pins 24 for scraping are alternately provided around the periphery. Either one of the cleaning plate 23 and the cleaning pin 24 may be provided, but it is preferable that the cleaning plate 23 and the cleaning pin 24 are circumferentially provided in combination.

The diameter of the screw blades 22 and the cleaning plate 23
The thickness and length of the cleaning pin 24 are not particularly limited as long as they can be cleaned efficiently. These are a screw blade 22 having substantially the same diameter, a cleaning plate 23 having substantially the same diameter and thickness, and a cleaning pin 23 having substantially the same length.
Can also be Moreover, it is preferable to provide two to three screw blades 22 for conveying the crushed pieces per one location, and the axial length per one location is 0.5 to 3 with respect to the diameter. preferable. The screw blades 22, the cleaning plate 23, and the cleaning pin 24 are alternately provided around each other, but the number or the number of the blades provided at one place may be the same. May be.

The pitch of the screw blades 22 needs to be set according to the number of rotations, but it is necessary to rotate at a relatively high speed in order to efficiently convey the crushed pieces, and one pitch is (0.3 to 3) × D (diameter of the screw blade 22) is preferable. If the pitch is less than 0.3D, the gap between adjacent screw blades is too small, and the crushed pieces may rotate together with the screw blade while being held in the gap, resulting in insufficient conveyance. Further, there are cases where the crushed pieces that have been sandwiched between the blades melt and the cleaning process cannot be continued. On the other hand, when the pitch exceeds 3D, the transfer efficiency decreases.

The number of rotations of the rotary shaft 21 is not particularly limited because the proper range varies depending on the size of the apparatus, the type of resin to be cleaned even in the same apparatus, the required degree of cleaning, and the like. Although the cleaning can be performed at any rotation speed, generally, the rotation speed at which the linear velocity of the tips of the cleaning plate 23 and the cleaning pin 24 is 0.5 to 40 m / sec, particularly 1 to 20 m / sec is preferable. At the rotation speed at which the linear velocity is less than 0.5 m / sec, it is not easy to sufficiently clean the surface of the crushed pieces even if the treatment time is extended. On the other hand, the linear velocity is 40m
If it exceeds / sec, the temperature in the cleaning device rises, the crushed pieces are softened and easily melted, and a large driving force is required.

At least a part of the inner surface of the container 1 and / or the surface of the screw blades 22, the cleaning plate 23 and the cleaning pin 24 that come into contact with the roughened crushed pieces are roughened, whereby the surface of the crushed pieces is Foreign matter is efficiently scraped off or scraped off. This rough surface is 40 to 2000 μm, especially 50 to 1000 μm.
m, and further, it can be formed by an uneven portion having a depth of 60 to 500 μm. If the depth of the irregularities is less than 40 μm, the foreign matter cannot be sufficiently removed, and the depth is 2000 μm.
If it exceeds, the surface of the crushed pieces is excessively scraped off including the resin, and the recovery rate of the resin decreases.

The size of the apparatus and the internal volume of the structure cleaning apparatus can be arbitrary depending on the amount of treatment, etc., but the size in the direction orthogonal to the rotary shaft 21 inside the container 1 is provided on the rotary shaft 21. Screw blade 2
It is preferable to appropriately set the diameter of 2 and the required gap between the inner surface of the container 1 and the tip of the screw blade 22. Further, the axial dimension of the rotary shaft 21 is preferably 5 to 30 times the diameter of the screw blades 22, and more preferably about 10 to 30.

If the dimension in the axial direction is less than 5 times the diameter of the screw blade 22, the action of conveyance and the action of washing cannot be sufficiently separated, and a part of the crushed pieces remains insufficiently washed. When the crushed pieces are conveyed to the discharge port and are insufficiently washed, the quality of the resin pieces for reuse may deteriorate. On the other hand, if it exceeds 30 times, the number of crushed pieces discharged without being washed can be reduced, but unless the strength of the rotating shaft 21 is increased or the supporting method thereof is modified, the container 1 is not cleaned. It is not easy to prevent contact between the inner surface and the screw blades 22 and the like, and the cost of the device increases significantly.

(2) Vertical batch type cleaning apparatus FIG. 4 is a schematic view showing a cross section of the vertical batch type cleaning apparatus. The container 1 is preferably cylindrical and can be formed of a metal such as stainless steel. This container 1
A crushed piece input port 11 is provided on the upper surface and a crushed piece discharge port 12 is provided on the lower surface. At the crushed piece discharge port 12, a piston type valve 121 in which the bottom surface of the container main body and the valve form the same surface when closed is provided, and after cleaning, the piston type valve 121 is opened to remove crushed pieces (resin pieces). The structure can be taken out.

Further, a water supply port 13 is provided at an upper portion of the side surface of the container 1, and a drain port 14 is provided at a lower portion of the side surface. The drain port 14 is connected to a water level adjusting drain passage 15 shown in FIG. ing. The water supply port 13 is provided on the upper surface of the container 1, and the drain port 14 is provided.
Can also be provided on the lower surface of the container 1. Further, in FIG. 4, the drain port 14 is formed over the entire circumference of the lower side surface of the container 1, but it may be provided in a part of the peripheral surface of the lower side surface. Further, the mutual positional relationship between the crushed piece input port 11 and the crushed piece discharge port 12 is not particularly limited, but it is preferable to provide them on a diagonal line in the cross section of the container 1.
By doing so, all the crushed pieces can be uniformly and efficiently washed.

The shape of the stirring blade 3 is not particularly limited, but it is preferable to use a paddle blade having a large surface area, a lattice blade, or the like. The stirring blade 3 is arranged at the center of the container 1,
At least a part of the inner surface of and the surface of the stirring blade 3 are roughened. In addition to the degree of this roughening, the ratio of the amount of crushed pieces in the container 1 to water, the openings of the slits or punching plates forming the drainage port 14, etc. are the same as in the horizontal continuous cleaning device of (1). It is the same.

[3] Application of Thermoplastic Resin Piece The thermoplastic resin piece can be mixed with an unused thermoplastic resin granulated product which is of the same kind as the thermoplastic resin forming the resin piece. The thermoplastic resin of the same kind means that the same or similar monomers, particularly polymers composed of the same monomers are used as the base resin. Further, when the copolymer is composed of two or more kinds of monomers, it is preferable that all the monomers are the same or similar, and the content of the repeating unit composed of each monomer is similar. Is more preferable. Further, this base resin is usually blended with a predetermined amount of various kinds of additives required for each resin product, and the types of these additives are also blended at the time of molding the recovered resin product. It is more preferable that they are of the same kind as those of (1) and (2) and their compounding amounts are almost the same. However, additives and the like are not essential, and may be a thermoplastic resin composition in which only unused base resin is mixed with a thermoplastic resin piece.

In the present invention, in addition to unused thermoplastic resin granulated products, non-standard products generated during molding of resin products, burrs, etc. may be used as they are or in an appropriate manner to collect unused thermoplastic resin. It can be used with granulated products. Also,
A thermoplastic resin composition containing a thermoplastic resin piece and an unused thermoplastic resin granulated product can also be provided for reuse as it is, and the thermoplastic resin composition is pre-melted and granulated, It can also be reused after it is made into pellets or other granulated products.

The thermoplastic resin pieces and the unused thermoplastic resin granulated product are mixed with each other by a device generally used for resin mixing such as a Banbury mixer, a pressure kneader, and a kneading roll. It can be carried out at the usual kneading temperature and kneading time of the resin. The thermoplastic resin composition can be granulated into pellets such as pellets by a general method such as pelletizing the molten composition extruded by extrusion molding or the like. Further, resin products using the obtained thermoplastic resin composition, by various methods such as extrusion molding, compression molding, injection molding, blow molding,
It can be manufactured under normal molding conditions.

The ratio of the thermoplastic resin pieces to the unused thermoplastic resin granulated product is not particularly limited, but when the total of these is 100% by mass, the unused thermoplastic resin granulated product is 5%. ~ 85% by mass, especially 10-80% by mass, and further 1
It is preferably 5 to 75% by mass. When the content of the unused thermoplastic resin granulated product is less than 5% by mass, it becomes difficult to reliably maintain the quality of the obtained resin product.
On the other hand, if the amount exceeds 85% by mass, there is no problem in terms of the quality of the resin product, but it is not preferable from the viewpoint of reuse of the used resin. In addition to thermoplastic resin pieces, non-standard products,
When burrs and the like are reused, it is preferable that the total amount of them be within the above range.

[0042]

The present invention will be described in more detail with reference to the following examples. The OA equipment collected from the market is disassembled, the casing made of ABS resin is sorted and sorted, and this is crushed using a commercially available crusher (Horai Co., model "UG-280", 10 mm screen), It was subjected to washing as crushed pieces. A paper sticker was attached to a part of the housing, and the surface was contaminated by long-term use, collection, disassembly, and handling during sorting. Hereinafter, this is referred to as a crushed piece (A). In addition, it was collected in the same way and the surface was painted.
A casing made of BS resin was similarly crushed. Hereinafter, this is referred to as a crushed piece (B). In addition, these crushed pieces have a flat plate shape, the maximum length in the plane direction is 2 to 15 mm, and the thickness is 1
It was ~ 4 mm, and its planar shape was rectangular.

Example 1 (Cleaning by the horizontal continuous cleaning device shown in FIGS. 1 and 2) (1) Cleaning device used The diameter of the screw blade provided on the rotary shaft of the cleaning device was 1
The length of the device is 2 mm of the diameter of the screw blade.
5 times, that is, 2.5 m. In addition, a slit with an opening of 1.2 mm is provided at the drainage port, the water level is set to a position slightly higher than the rotation axis by a water level adjusting pipe, and the mass of the fragment (A) and the washing water in the container are approximately the same. Was set.

Further, on the rotating shaft, screw blades and a plurality of cleaning plates formed by arranging semicircular discs with a phase shift of 90 ° at intervals of 40 mm are formed in each axial direction. The lengths and diameters are alternately arranged at a dimensional ratio of 2 to 4. Further, a part of the screw blade is cut out so that the transportability is adjusted, and 100 to 100 is formed on the entire inner surface of the container and the surface of the screw blade and the cleaning plate.
The surface is roughened by providing unevenness having a depth of 200 μm.

(2) Washing operation 50 k of crushed pieces (A) are put into the crushed piece input port of this cleaning device.
Charged at a rate of g / hour. On the other hand, water was supplied at a rate of 30 kg / hour from the crushed piece charging port, and was also supplied from two water supply ports provided in the middle portion in the length direction of the apparatus. The amount of water supplied is 1 from the open end of the drainage channel.
It was adjusted to be 00 kg / hour.

Then, the rotation speed of the rotary shaft is set to 400 rpm.
(The linear velocity at the tip of the cleaning plate is 2.1 m / sec.), And the crushed piece discharge port does not pass through the slit provided in the drainage port to the crushed piece (A) after the treatment. A recovered product in the form of a slurry in which dust such as a paper seal was mixed was obtained. The recovered product is scattered on a vibrating sieve having a mesh of 2 mm, and while water is sprinkled, fragments of paper seals and dust are separated and removed, and then dehydrated by a dehydrator, and dried by a dryer under normal pressure at 80 After drying at 0 ° C. for 2 hours, foreign matters having a small specific gravity which could not be completely removed by water spray were separated by an air classifier and removed to collect thermoplastic resin pieces.

(3) Inspection of foreign matter after cleaning 10 g of a thermoplastic resin piece was placed between clean aluminum foils sandwiched between stainless steel plates at a temperature of 220 ° C.
About 200 mm in diameter by compression molding under a pressure of 4 MPa
And the sheet. Then, the aluminum foil was peeled off from this sheet, and both surfaces of the sheet were observed with a magnifying glass to count foreign matters. The corners of the edges of the flat surface and the end surface were rounded. The results are shown in Table 1.

Comparative Example 1 In order to wash in the same manner as in Example 1 except that water was not used, the crushed pieces (A) were started to be charged, but after a while, the crushed pieces began to melt and the load of power was applied. Became too large and it became impossible to operate.

Comparative Example 2 In Comparative Example 1, the number of revolutions at which the crushed pieces did not melt was examined, and the number of revolutions of the rotary shaft was reduced to 50 rpm (the linear velocity at the tip of the cleaning plate was 0.26 m / sec). Other than that, it was washed in the same manner as in Comparative Example 1 without using water. Crushed pieces after treatment (A) discharged from the crushed piece discharge port after washing
Was subjected to post-treatment in the same manner as in Example 1 to separate and remove foreign matter, and the foreign matter in the washed resin piece was counted by the same method as in Example 1 to observe the shape and the like. The results are shown in Table 1.

Example 2 Using the crushed pieces (B), the amount of washing water supplied from the middle portion was increased so that the drainage amount from the open end of the drainage channel was 200.
Washing was performed in the same manner as in Example 1 except that the concentration was adjusted to kg / hour. After washing, the treated crushed pieces (B) discharged from the crushed piece discharge port were post-treated in the same manner as in Example 1 to separate and remove foreign matter, and washed in the same manner as in Example 1. The foreign matters on the resin pieces were counted, and the shape and the like were observed. The results are shown in Table 1.

Comparative Example 3 Cleaning was performed in the same manner as in Example 2 except that the rotation speed of the rotary shaft was reduced to 50 rpm. After washing, the treated crushed pieces (B) discharged from the crushed piece discharge port were post-treated in the same manner as in Example 1 to separate and remove foreign matter, and washed in the same manner as in Example 1. The foreign matters on the resin pieces were counted, and the shape and the like were observed. The results are shown in Table 1.

Example 3 (Washing by the vertical batch type washing apparatus shown in FIG. 4) A cylindrical container has an inner diameter of 400 mm and a height of 500 mm.
At the center, a lattice blade with an outer diameter of 360 mm is arranged,
200 to 300 on the entire inner surface of the container and the surface of the lattice wing
Roughness having a depth of μm is provided and roughened.

22 kg of crushed pieces (A) were added to this washing device.
And 20 kg of water were charged, the height of the water level adjusting tube was adjusted to the liquid level at this point, the lattice vanes were rotated at 300 rpm, and water was supplied at a rate of 20 liters / hour and discharged while 20 Washed for minutes. After washing, the piston type discharge valve was opened to take out the crushed pieces (A) after the treatment, and the same post-treatment as in Example 1 was carried out to separate and remove foreign matters.
The foreign matters on the washed resin pieces were counted in the same manner as in (1), and the shape and the like were observed. The results are shown in Table 1.

Comparative Example 4 Cleaning was performed in the same manner as in Example 3 except that a cleaning device in which the entire inner surface of the container and the surface of the stirring blade were not roughened was used. After washing, the piston type discharge valve was opened to take out the crushed pieces (A) after the treatment, and the same post-treatment as in Example 1 was carried out to separate and remove foreign matters, and the crushed pieces were washed in the same manner as in Example 1. The foreign matters on the resin pieces were counted, and the shape and the like were observed. The results are shown in Table 1.

[0055]

[Table 1]

According to the results shown in Table 1, by roughening the portion of the cleaning device that comes into contact with the crushed pieces, the corners of the edges between the flat surface and the end surface of the washed resin piece were rounded. . Further, it can be seen that the resin piece has very few foreign matters, and in particular, there is no foreign matter having a maximum length exceeding 0.25 mm. On the other hand, in Comparative Example 1, it was impossible to operate due to melting of the crushed pieces, and in Comparative Examples 2 to 4, most of the corners of the edges between the flat surface and the end surface of the resin piece had an acute angle. Furthermore, in Comparative Examples 2 and 4, especially Comparative Example 2, a large number of large and small foreign matters were present, and in Comparative Example 3, the foreign matter could not be counted because of a large amount of coating film residue, and both were extremely inferior. I know that

It should be noted that the present invention is not limited to the above-mentioned embodiment, but can be variously modified according to the purpose, application, etc. For example, in the horizontal continuous cleaning apparatus, each of the water supply port 13 and the drainage port 14 may be provided at one place, but may be provided at a plurality of places. In particular, by providing a plurality of water supply ports 13 from one end side to the other end side of the container 1, dust and the like generated by the cleaning is quickly flowed to the drain port 14, and the cleaning device is supplied through the water level adjusting drain channel 15. Can be discharged outside. Furthermore, it is possible to sufficiently prevent dust and the like from reattaching to the crushed pieces, which is preferable.

Further, the openings of the slits, punching plates, etc. provided in the drainage port 14 may be of a size that allows water and dust to pass through, but does not allow crushed pieces to pass through. It is preferable in terms of strength that the slits have a size of about 3 to 2 mm. Further, the drain port 14 can be provided on the bottom surface or the side surface of the container 1, but it is preferably provided on the bottom surface for adjusting the water level, and when it is provided on the side surface, it is preferably provided at a low position. Also,
When the screw blade 22 provided on the rotating body has a large carrying capacity and the residence time in the portion where the cleaning plate 23 and the cleaning pin 24 are provided is insufficient, a part of the screw blade is cut out to perform the carrying capacity and the cleaning action. You can also adjust the balance with.

Further, the shape of the cleaning plate 23 is not particularly limited, and the planar shape as viewed from the axial direction of the rotary shaft 21 may be a circle, a triangle, a polygon such as a quadrangle, or the like. The cleaning plate 23 does not necessarily have to have a target shape with respect to the rotating shaft 21, and may be inclined with respect to the rotating shaft 21 so as to have a transporting function. Further, by combining the one inclined in the conveying direction and the one inclined in the opposite direction, the surface of the crushed pieces can be more strongly rubbed or scraped, and the cleaning efficiency can be improved. Furthermore, the cross-sectional shape of the cleaning pin 24 can be circular or polygonal, such as triangular or quadrangular, but it is preferable that the cross-sectional shape is polygonal because the cleaning efficiency is high. The cleaning pin 24 does not necessarily have to stand upright with respect to the rotary shaft 21, and may have an appropriate angle.

Further, when either the inner surface of the container or the surface of the rotating body is roughened, it is more preferable that the inner surface of the container is roughened because foreign substances can be easily removed. Furthermore, a cleaning device in which both the inner surface of the container and the surface of the rotating body are roughened can remove foreign matter more easily, which is particularly preferable. Further, the roughening due to the uneven portion or the like may be the same or different between the inner surface of the container and the surface of the rotating body. Furthermore, the entire surface of each of the roughened portions of the inner surface of the container and the surface of the rotating body may be roughened to the same degree, or the degree of roughening may be different depending on the location. . For example, on the inner surface of the container 1 or the like, it is not necessary to make constant from the inlet to the outlet of the crushed pieces, it is rough on the inlet side and relatively smooth on the outlet side, and so on. The cleaning efficiency can also be adjusted. Further, if necessary, the cleaning efficiency can be improved by blending water with various abrasives and the like.

Although a two-axis cleaning device is illustrated in FIG. 1, this device is not necessarily a two-axis type.
A single axis may be used, or a multi-axis device having three or more axes may be used. However, with a single shaft, the movement of the crushed pieces in the apparatus becomes monotonous, and the cleaning efficiency tends to decrease. On the other hand, 3
Above the axis, the structure becomes complicated and it becomes an expensive device,
Considering cleaning efficiency and cost, a biaxial device is most preferable.

[Brief description of drawings]

FIG. 1 is a schematic view showing a cross section of an example of a horizontal continuous cleaning apparatus.

FIG. 2 is a schematic diagram showing a vertical cross section of the cleaning apparatus shown in FIG.

FIG. 3 is a schematic view showing a cross section of a water level adjusting drainage channel.

FIG. 4 is a schematic view showing a cross section of an example of a vertical batch type cleaning apparatus.

[Explanation of symbols]

1; container, 11; crushed piece input port, 12; crushed piece discharge port,
121; piston type valve, 13; water supply port, 14; drainage port, 15; water level adjusting drainage channel, 15a; drainage pipe, 15
b; water level adjusting pipe, 15c; O-ring for sealing, 2; rotating body, 21; rotating shaft, 22; screw blade, 23; cleaning plate, 24; cleaning pin, 3; stirring blade, 4; drive motor.

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 4F201 AA50 AC01 AM10 BA04 BA09                       BC25 BL47 BN31 BQ53 BR38                 4F301 AA12 AA13 AA14 AA15 AA17                       AA25 AA26 AA27 AA28 AA29                       AD03 BF04 BF05 BF09 BF27                       BF29 BF31

Claims (3)

[Claims] 1. A crushed piece of a thermoplastic resin product,
A thermoplastic resin piece having rounded corners and no foreign matter adhering to the surface. 2. A container and a rotating body mounted inside the container, wherein the container has a resin crushed piece inlet provided at an upper part of one edge and a resin crushed piece provided at a lower part of the other edge. Vent,
A water supply port and a drain port are provided, and a drainage channel for adjusting the water level is connected to the drain port. The rotating body includes a rotating shaft, screw blades provided around the rotating shaft, a plurality of cleaning plates, and cleaning pins. And at least one of the inner surface of the container and / or
Alternatively, using a cleaning device in which at least a part of the surface of at least one of the screw blade, the cleaning plate, and the cleaning pin is roughened, and the crushed pieces are washed with water as a medium. The thermoplastic resin piece according to claim 1. 3. A container and a stirring blade are provided, and the container has a resin crushed piece input port and a water supply port provided in an upper part, and a resin crushed piece discharge port and a drain port provided in a lower part, A water level adjusting drainage channel is connected to the drainage port, and a washing device in which at least a part of the inner surface of the container and / or the surface of the stirring blade is roughened is used, and the crushing is performed using water as a medium. The thermoplastic resin piece according to claim 1, which is obtained by washing the piece.