JP3729668B2 - Manufacturing method of recycled resin - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing a clean recycled resin by removing and separating dirt from a used resin molded product to which dirt such as contents and labels adheres.
[0002]
[Prior art and problems to be solved by the invention]
A method of collecting and washing a resin molded body such as a used polyethylene terephthalate (hereinafter referred to as PET) bottle and manufacturing a recycled resin includes a wet method for removing dirt from the molded body by washing with water and a metal pin. There is known a dry method for removing dirt on a molded body by collision or friction. However, since the wet method has many sorting / separation processes, the efficiency cannot be increased, and the dry method requires cleaning by a wet method as a pretreatment, and is performed in a batch process. The manufacturing price becomes high.
[0003]
In addition to these methods, methods for injecting dry ice particles onto an object to be cleaned are known (Japanese Patent Laid-Open Nos. 61-15749, 5-318710, and 6-182306, (Kaihei 8-202269, JP-A-10-13814). However, the methods described in these publications are not suitable for cleaning an object to be cleaned having a small specific gravity, such as a resin molded body, because the object to be cleaned is a fixed surface and an externally exposed surface. .
[0004]
Accordingly, an object of the present invention is to provide a method capable of producing a clean recycled resin by removing and separating dirt from a used resin molded product to which dirt such as contents and labels adheres.
[0005]
[Means for Solving the Problems]
The present invention relates to a clean resin in which deposits are removed by crushing a used resin molded body into resin pieces, and then causing the resin pieces to collide with dry ice particles in a flowing state to wash the resin pieces. A method for producing a recycled resin as a piece ,
Using a separation apparatus having a chamber having an upper inlet, a lower inlet, an upper outlet and a lower outlet, the resin piece is introduced from the upper inlet and the dry ice particles are introduced from the lower inlet by the carrier fluid. Transporting and introducing, causing the resin pieces to collide with the dry ice particles in the chamber, removing the deposits from the resin strips to form the clean resin strips, and removing the deposits by the transport fluid. The above object is achieved by providing a method for producing a recycled resin that is transported and taken out from the upper outlet, and the clean resin piece is taken out from the lower outlet, and the deposit and the clean resin piece are separated and individually recovered. Is achieved.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the manufacturing method of the recycled resin of this invention is demonstrated with reference to drawings based on the preferable embodiment.
[0007]
The method for producing a recycled resin according to this embodiment is roughly divided into (1) a pretreatment step, (2) a deposit cleaning / separation step, and (3) a posttreatment step.
[0008]
In the pretreatment step, first, the used resin molded bodies that have been compressed and collected after collection are individually separated. A bale demolition machine or the like is used for this separation. Next, foreign matters such as glass and metal are removed by gravity sorting using jet air. Further, a near-infrared spectroscopic analysis is performed on the used resin molded body by a sorting device equipped with a near-infrared sensor, and the molded body is sorted for each type of resin. This separation improves the efficiency of resin reuse. The used resin moldings sorted for each type of resin are further sorted for each color as necessary. Visible light spectroscopic analysis is used for color separation. The used resin moldings thus sorted are crushed by a flaking crusher to form a flaky resin piece having a side of about 1 to 10 cm.
[0009]
The obtained resin piece is subjected to a cleaning / separation process of the deposit. A separation apparatus 1 shown in FIG. 1 is used for this cleaning / separation process. The separation device 1 includes a first chamber 2 and a second chamber 3. The first chamber 2 has an upper inlet 4, a lower inlet 5, an upper outlet 6 and a lower outlet 7. The second chamber 3 has an upper inlet 8, a lower inlet 9, an upper outlet 10, and a lower outlet 11. The upper outlet 6 of the first chamber 2 communicates with the upper inlet 8 of the second chamber 3.
[0010]
The resin piece with the attached matter such as the contents and the label attached thereto is introduced into the first chamber 2 from the upper introduction port 4 of the first chamber 2 by a conveying means such as a belt conveyor and falls in the first chamber 2. . At the same time, dry ice particles are introduced into the chamber by the carrier fluid from the lower inlet 5 of the first chamber 2 and ascend in the chamber. Then, in the first chamber 2, the resin pieces are opposed to and collided with the dry ice particles in a fluid state to separate and remove the deposits adhering to the surface of the resin pieces. As a result, a clean resin piece from which deposits have been removed is obtained. Since this collision is performed at a low temperature in the presence of dry ice, when the label is affixed to the resin piece via an adhesive, the adhesive becomes in the state below its glass transition point and loses its viscosity. Separation and removal of the resin piece, the label and the adhesive can be easily performed. In addition, even when a high-viscosity liquid that is not usually easy to remove is attached to the resin piece, the liquid is solidified, so that it can be easily separated and removed.
[0011]
The clean resin piece settles in the first chamber 2 and is discharged from the lower outlet 7 of the first chamber 2 according to the balance between the terminal settling velocity due to gravity and the velocity of the carrier fluid moving upward from the lower inlet 5.・ Recovered. On the other hand, the deposit separated from the resin piece is transported by the transport fluid, moves up in the first chamber 2, is discharged from the upper outlet 6 of the first chamber 2, and communicates with the upper outlet 6. It is introduced into the second chamber 3 through the upper inlet 8 of the chamber 3. The deposits are further separated and collected for each type in the second chamber 3. In this way, the resin piece with the attached matter is separated into the clean resin piece and the attached matter with a very high degree of separation and collected individually.
[0012]
The carrier fluid used for transporting the dry ice particles is not particularly limited as long as it does not adversely affect the cleaning of the resin piece, but it is preferable to use air from the viewpoint of handleability and economy. The size of the dry ice particles is preferably 100 to 5000 μm, particularly 150 to 1000 μm from the viewpoint that the resin piece can be washed even if part of the ice is vaporized during the transfer and can be transferred with the transfer fluid. Such dry ice particles can be obtained, for example, by the method described in JP-A-6-182306, column 4, lines 7 to 16 described above.
[0013]
If the total pressure of the dry ice particles and the carrier fluid introduced into the first chamber 2 is too low, the adhered matter such as the label pieces peeled off from the resin pieces or the dry ice particles themselves will fall, and if too high, the resin From the point that it is difficult to introduce the piece into the first chamber 2, it is preferably 0.05 to 0.8 MPa [gage], particularly preferably 0.1 to 0.5 MPa [gage]. The amount of the dry ice particles introduced into the first chamber 2 is 0.1 to 10 kg / h, particularly 0.3 to 5 kg with respect to the resin piece 10 kg / h in relation to the amount of the resin piece to be processed. / H is preferable.
[0014]
In the second chamber 3, the deposits separated in the first chamber 2 are introduced through the upper inlet 8 as described above. At the same time, dry ice particles are introduced into the chamber from the lower introduction port 9 of the second chamber 3 by the carrier fluid, and rise in the chamber. Then, in the second chamber 3, the deposit is opposed to and collided with the dry ice particles in a fluid state to separate the deposit into a label piece and other dirt components (for example, a liquid synthetic detergent).
[0015]
The separated label piece settles in the second chamber 3 due to the balance between the terminal settling velocity due to gravity and the velocity of the carrier fluid moving upward from the lower inlet 9 to the lower outlet 11 of the second chamber 3. It is discharged and collected from. On the other hand, other dirt components separated from the label pieces rise in the second chamber 3 and are discharged and collected from the upper outlet 10 of the second chamber 3. In this way, the deposits adhering to the resin pieces are finely separated for each type in the second chamber 3 and collected individually.
[0016]
Since the label piece taken out from the lower outlet 11 of the second chamber 3 is clean and separated from other dirt components, it can be collected and recycled. As a result, the recycling rate of the used resin molding is further increased. Further, the dry ice particles discharged from the upper outlet 10 of the second chamber 3 are sublimated to become a gas and then collected, cooled, and again become dry ice particles. Therefore, unlike the above-described wet method and dry method of cleaning a resin molded body, the method of this embodiment also has an advantage that it can be cleaned in a closed system. Furthermore, since the sublimation of dry ice occurs spontaneously, there is also an advantage that the final soil component remains without any other special operation.
[0017]
As the transport fluid used for transporting the dry ice particles in the second chamber 3, the same fluid as that used in the first chamber 2 can be used. Also, the size of the dry ice particles can be the same as that used in the first chamber 2.
[0018]
The total pressure of the dry ice particles and the carrier fluid introduced into the second chamber 3 can be generally lower than in the case of the first chamber 2, and is 0.001 to 0.1 MPa [gage], particularly 0.01 to It is preferably 0.1 MPa [gage]. The amount of dry ice particles introduced into the second chamber 3 is 0.01 to 1 kg with respect to the amount of deposit of 10 kg / h in relation to the amount of deposit on the resin piece introduced into the first chamber 2. / H, particularly preferably 0.03 to 0.5 kg / h.
[0019]
In the post-treatment process, a clean resin piece as a recycled resin is pelletized or consolidated and used as a raw material resin for a new resin product.
[0020]
As mentioned above, although the manufacturing method of the recycled resin of this invention was demonstrated based on the preferable embodiment, this invention is not restrict | limited to the said embodiment, A various change is possible.
For example, although the separation device above Symbol embodiments are those having two chambers, may be used, equipped with a chamber of only one instead of this, or three or more depending on the fractionation the number You may use what provided the chamber of this.
Moreover, you may use as a recycled resin in the state as it is, without performing the pelletization thru | or compacting of the clean resin piece in a post-processing process.
Further, when a cap or the like is attached to the used resin molded body, a step of separating the cap or the like from the molded body may be performed before crushing the molded body in the pretreatment step.
[0021]
[Example 1]
As a used PET bottle container, a container of Family Fresh Compact (trade name of detergent manufactured by Kao Corporation) with a cap removed in advance was prepared. The container was crushed into 3-4 cm square flakes to obtain flake resin pieces. The flake-shaped resin piece has a label adhered to the container as well as the rest of the contents. Then, a recycled resin was produced using the separation apparatus shown in FIG. 1 under the following operating conditions.
[0022]
As an evaluation of the degree of cleaning of the obtained recycled resin, 10 pieces of resin pieces before washing and 10 pieces of resin pieces obtained from the lower outlet of the first chamber are cut into 1 to 2 cm squares, and 100 ml of tap water is contained. Each was placed in a glass bottle with a lid, and vigorously vibrated by hand for 30 seconds, and the amount of foaming after 10 seconds was measured. In addition, as an evaluation of the degree of separation, the ratio of the number of objects obtained from the lower outlet of the first chamber, the lower outlet of the second chamber, and the upper outlet of the second chamber, respectively, and other solids Asked. These results are shown below.
[0023]
[Operating conditions]
・ Flake resin piece supply amount: 10 kg / hr
・ Size (average) of dry ice particles: 520 μm
・ Carrying fluid; air <first chamber>
・ Total pressure of dry ice particles and carrier fluid; 0.3 MPa [gage]
・ Dry ice particle introduction amount: 3 kg / hr
<Second chamber>
・ Total pressure of dry ice particles and carrier fluid; 0.04 MPa [gage]
・ Dry ice particle introduction amount: 0.1 kg / hr
[0024]
〔result〕
<Evaluation of cleanliness (foaming amount)>
-Resin piece before washing; 14 cm ³
-Resin piece obtained from the lower outlet of the first chamber; 0 cm ³
<Separation degree evaluation>
・ Lower outlet of the first chamber; (label piece + resin piece with label) / resin piece without label = 13 pieces / 3897 pieces ・ Lower outlet of the second chamber; (resin piece with label + resin piece without label) / Label piece = 14 pieces / 1581 pieces-Upper outlet of the second chamber; (label piece + resin piece with label + resin piece without label) = 13 pieces [0025]
As is clear from the above results, it can be seen that the resin piece obtained from the lower outlet of the first chamber has no detergent attached and is clean. Furthermore, it can be seen that the target product can be obtained with a very high degree of separation from each extraction section in the separation apparatus.
[0026]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to this invention, the method which removes and isolate | separates dirt from the used resin molded object to which dirt, such as a content and a label, adhered, and can manufacture clean recycled resin easily is provided. According to the method of the present invention, an extremely clean recycled resin can be obtained with a high degree of separation. The method of the present invention is particularly effective when a recycled resin is produced from a used resin container to which a high-viscosity liquid or the like that is usually not easily removed is attached.
[Brief description of the drawings]
FIG. 1 is a schematic view showing a separation apparatus preferably used in the method for producing a recycled resin of the present invention.
[Explanation of symbols]
1 Separator 2 First chamber 3 Second chamber

Claims (3)

After the used resin molding is crushed into resin pieces, the resin pieces are collided with dry ice particles in a fluidized state to wash the resin pieces and regenerate them into clean resin pieces from which deposits have been removed. A resin manufacturing method comprising :
Using a separator having a chamber having an upper inlet, a lower inlet, an upper outlet, and a lower outlet, the resin piece is introduced from the upper inlet and the dry ice particles are introduced from the lower inlet by the carrier fluid. After transporting and introducing, causing the resin pieces to collide with the dry ice particles in the chamber, the deposits are removed from the resin pieces to form the clean resin pieces, and the removed deposits are removed by the transport fluid. A method for producing a recycled resin, which is transported and taken out from the upper outlet, and the clean resin piece is taken out from the lower outlet, and the deposit and the clean resin piece are separated and collected individually . The separation device is composed of a first chamber and a second chamber,
The first chamber has an upper inlet, a lower inlet, an upper outlet and a lower outlet, and the second chamber has an upper inlet, a lower inlet, an upper outlet and a lower outlet, The upper outlet of one chamber communicates with the upper inlet of the second chamber,
The resin piece is introduced from the upper introduction port of the first chamber, and the dry ice particles are carried and introduced by the carrier fluid from the lower introduction port of the first chamber, and the resin piece is put into the dry ice in the first chamber. Colliding with particles to remove the deposits from the resin pieces to form the clean resin pieces, the removed deposits are transported by the transport fluid, and discharged from the upper outlet of the first chamber. Introducing into the second chamber through the upper inlet of the second chamber communicating with the outlet and taking out the clean resin piece from the lower outlet of the first chamber;
The deposit introduced into the second chamber is caused to collide with dry ice particles transported and introduced by the transport fluid from the lower inlet of the second chamber in the second chamber, and the deposit is separated from the label pieces. 2. The regeneration according to claim 1, wherein the label piece is separated from other dirt components and discharged and collected from the lower outlet of the second chamber, and the other dirt components are discharged and collected from the upper outlet of the second chamber. Manufacturing method of resin. The total pressure of the dry ice particles and the transport fluid introduced into the first chamber is 0.05 to 0.8 MPa. [gage] The amount of the dry ice particles introduced into the first chamber is 0.1 to 10 kg / h with respect to 10 kg / h of the resin piece,
The total pressure of the dry ice particles and the transport fluid introduced into the second chamber is 0.001 to 0.1 MPa.  [gage] The method for producing a recycled resin according to claim 1, wherein the amount of the dry ice particles introduced into the second chamber is 0.01 to 1 kg / h with respect to 10 kg / h of the deposit.

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