JP3300652B2 - Method for recovering expanded polystyrene - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for recovering expanded polystyrene, which is obtained by processing an expanded polystyrene molded article frequently used as a packing material or the like into pellets and recovering the pellet.

[0002]

2. Description of the Related Art Compared with pulp molding materials made from recycled milk cartons, cardboards, newsprints, etc., foamed polystyrene moldings have good appearance, excellent impact relaxation properties, and can be easily processed into arbitrary shapes. Not to mention products and AV equipment, they are often used as packing materials for various products, but on the other hand, they generate high heat during incineration, shorten the life of the incinerator, and do not decompose in the soil. It is also a cause of pollution.

[0003] Therefore, there has been proposed a method for recovering expanded polystyrene in which the expanded polystyrene molded body is recovered and reused as described below.

(A) Heating the expanded polystyrene molded body
A heat shrinking method in which a block is melted and reduced in volume, and the block is processed into pellets by a pelletizer and collected.

(B) A method in which a foamed polystyrene molded body is dissolved in a general-purpose organic solvent such as a benzene-based or ketone-based solvent, and then the organic solvent and the polystyrene are separated and recovered.

(C) The expanded polystyrene molded body is brought into contact with a shrinking agent comprising at least one selected from limonene, isoamyl acetate, benzyl propionate, and ethyl butyrate to shrink the volume thereof, and then the shrinking agent and polystyrene And separating and recovering the same (JP-A-5-26306)
No. 5).

[0007]

Among the above prior arts, the heat shrinking method (a) involves heating at a high temperature when heating and melting the expanded polystyrene molded body, so that the polystyrene is thermally decomposed. Odor is generated and the molecular weight of the recovered polystyrene is reduced, making it difficult to reuse.

On the other hand, in the method (b) of dissolving in a general-purpose organic solvent, since this organic solvent has a considerable adverse effect on the human body and the environment, it is necessary to separate and recover the organic solvent for reuse. Separation equipment is indispensable, resulting in high costs. In the method (c), in which the expanded polystyrene is brought into contact with a shrinking agent to reduce the volume, the shrinking agent itself is safe for the human body and the environment. A separating device for reusing the waste is indispensable, and there is a problem that the cost is increased.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and has no fear of generating an odor or reducing the molecular weight of polystyrene, and can reduce the cost of recovery. It is intended to realize a method for recovering polystyrene.

[0010]

Means for Solving the Problems To achieve the above object, a method for recovering expanded polystyrene according to the present invention comprises the steps of: crushing a foamed polystyrene molded product into crushed pieces of a predetermined size by a crusher; For air transport by airflow
While transferring from one end of the pipe to the other end, the outer wall of the pipe
Before and heated to a predetermined temperature by the disposed a heating means
The volume of the shredded pieces is shrunk, and the shrunk shrunken pieces whose volume shrinks are subsequently processed into pellets by a pelletizer equipped with a screw type extruder.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A method for recovering expanded polystyrene according to one embodiment of the present invention will be described with reference to FIG.

(1) The foamed polystyrene molded article 1 is supplied to a crusher 3 through a crusher supply port 2 and crushed into crushed pieces 18 of a predetermined size.

(2) The crushed pieces 18 crushed by the above (1) are fed into a pipe supply port 4 of a pipe 6 for pneumatically transporting the crushed pieces 18 to a screw type extruder 9 described later.

(3) After the above (2), the crushed pieces 18
Is pneumatically transported in the pipe 6 by the airflow generated by the blower 5 disposed at one end of the pipe 6,
While being transferred to the other end of the pipe 6, the volume is shrunk by heating to a predetermined temperature by the heating means 7 disposed on the outer wall of the pipe 6, and the shrunk crushed pieces 19 whose volume has shrunk are Are separated by a gas-solid separator 21 disposed at the other end of the extruder, and subsequently supplied to the screw type extruder 9 from the extruder supply port 8.

On the other hand, the gas separated by the gas-solid separator 21 is discharged into the atmosphere or returned to the suction side of the blower 5 and circulated.

[0016]

(4) After the above (3), the contracted crushed pieces 19 whose volume supplied into the screw type extruder 9 has contracted.
Is kneaded and melted by heating by a heating means (not shown) provided on the outer wall of the cylinder 10 and shearing heat generated by the screw 11 while being transferred to the downstream side by the screw 11 rotating in the cylinder 10. Dice 1
It is extruded as a strand 13 from 2.

On the other hand, the foaming agent contained in the shrunk crushed pieces is removed from the machine in a gaseous state by a method such as vacuum suction through a vent port 20 through a vacuum pump 22.

(5) After the above (4), the extruded strand 13 is cooled by a cooling liquid 15 in a strand bath 14 and then sequentially cut into a predetermined length by a cutting means 16 to form a pellet 17. .

The pelletizer provided with the screw type extruder includes the die 1 of the screw type extruder 9 described above.
The strand 13 extruded by 2 is cooled by a strand bath 14 and then sequentially cut to a predetermined length by a cutting means 16 into pellets 17. The pellets 17 are arranged close to the die discharge side. A pelletizer equipped with another known screw type extruder such as one equipped with a rotary blade or the like can be used.

[0021]

Since the present invention is configured as described above, the following effects can be obtained.

[0022] The crushed pieces of expanded polystyrene moldings, air flow
Is transferred from one end to the other end of the pipe for pneumatic transport
In the meantime, the volume is shrunk by being heated to a predetermined temperature by a heating means disposed on the outer wall of the pipe, and the shrunk crushed pieces having the shrunk volume are continuously supplied to the screw type extruder. Therefore, the throughput of the expanded polystyrene molded article in the screw extruder can be increased. Further, the amount of heat required for kneading and melting in the screw type extruder is reduced. As a result, the length of the cylinder of the screw-type extruder can be shortened, and the recovery cost is reduced. Also,
Since the crushed pieces of the expanded polystyrene are not unnecessarily heated, good-quality pellets can be obtained without generating a bad odor or reducing the molecular weight due to thermal decomposition.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a method for collecting expanded polystyrene according to an embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Expanded polystyrene molded body 2 Crusher supply port 3 Crusher 4 Pipe supply port 5 Blower 6 Pipe 7 Heating means 8 Extruder supply port 9 Screw type extruder 10 Cylinder 11 Screw 12 Die 13 Strand 14 Strand bath 15 Coolant 16 Cutting Means 17 Pellets 18 Crushed pieces 19 Shrinked crushed pieces 20 Vent port 21 Gas-solid separator 22 Vacuum pump

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-5-92429 (JP, A) JP-A-5-92428 (JP, A) JP-A-5-162136 (JP, A) JP-A Sho 62- 121018 (JP, A) Japanese Utility Model 3-103709 (JP, U) Japanese Utility Model 3-39512 (JP, U) Japanese Utility Model 5-53909 (JP, U) Japanese Utility Model 51-156066 (JP, U) (58) Field surveyed (Int.Cl. ⁷ , DB name) B29B 17/00-17/02 C08J 11/00-11/28 B09B 3/00-5/00

Claims (1)

(57) [Claims] 1. A foamed polystyrene molded body is crushed by a crusher into crushed pieces of a predetermined size, and then the crushed pieces are air- crushed.
Transfer from one end to the other end of pipes that pneumatically transport by flow
In the meantime, the volume of the shredded pieces is shrunk by heating to a predetermined temperature by a heating means disposed on the outer wall of the pipe, and the shrunk pieces of shrunk volume are continuously extruded by screw-type extrusion. A method for recovering expanded polystyrene, comprising processing into pellets by a pelletizer equipped with a machine.