JP2003313359A - Apparatus for recycling plastic and producing method of recycled plastic - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus and a method for obtaining recycled plastic using plastic wastes containing an insoluble substance as a material. <P>SOLUTION: The plastic recycling apparatus 1 comprises producing recycled plastic using plastic wastes containing an insoluble substance as a material. The apparatus is provided with a heating part 3 for heating the material and a crushing part 5 for finely crushing the insoluble substance contained in the material heated and melted by the heating part 3. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plastic recycling apparatus for producing recycled plastic using plastic waste containing insoluble substances such as paper / wood chips and thermosetting resin, and the production of recycled plastic. It is about the method.

[0002]

2. Description of the Related Art When reusing plastic waste, if the plastic waste is only a thermoplastic resin, it is melted by heating and kneaded and granulated to obtain an injection molding raw material. Can be reused as. However, in the actual plastic waste, foreign matter is mixed, and it is very difficult to use it as recycled plastic. Examples of foreign matter include wood chips (split chopsticks, etc.), paper, aluminum vapor-deposited sheet, thermosetting resin, and other insoluble substances. If granulation is performed with such insoluble substances mixed, The piece causes nozzle clogging, gate clogging, or die clogging during injection molding or extrusion molding. Moreover, if the foreign matter remains mixed, the foreign matter will make the pellets and molded articles brittle. Therefore, it is not possible to obtain the quality that enables reuse of plastic.

For these reasons, plastic waste has not been recycled and is currently disposed of by incineration or landfill. The present invention has been made in view of the above problems, and an object of the present invention is to provide an apparatus and a method for obtaining a recycled plastic using a plastic waste containing an insoluble substance as a material.

[0004]

SUMMARY OF THE INVENTION The present invention is a plastic recycling apparatus for producing recycled plastic using plastic waste containing an insoluble substance as a material, and a heating unit for heating the material. And a crushing unit for crushing the insoluble substance contained in the material heated and melted by the heating unit to make it finer. The infusible substance contained in the plastic waste heated and melted by the heating part is finely divided by the crushing part and dispersed in the material in the molten state. The waste can be used as recycled plastic.

Further, the present invention comprises a screw for transferring the material to the crushing section, wherein the crushing section comprises a fixed body and a rotating body rotated by a rotational force of the screw, and the fixed body. It is preferable that the insoluble substance is miniaturized by a shearing action with the rotating body. By providing such a configuration, the crushing section can miniaturize the insoluble substance by utilizing the rotation of the screw, and the structure can be simplified.

As a more specific structure of the crushing portion, an inner cylinder, an outer cylinder coaxially arranged outside the inner cylinder and relatively rotatable, an outer peripheral surface of the inner cylinder and an inner peripheral surface of the outer cylinder. A shear irregularity portion formed on at least one of the surfaces,
The insoluble substance contained in the material sent between the inner cylinder and the outer cylinder is sheared by the shear uneven portion by relatively rotating the inner cylinder and the outer cylinder. Then, it is preferable to make it finer.

The present invention relating to a method for producing recycled plastic is a method for producing recycled plastic using plastic waste containing an insoluble substance as a material.
It is characterized in that recycled plastic is obtained by crushing the insoluble substance contained in the melted material into fine particles in a state where the plastic waste contained in the material is heated and melted. By refining the insoluble substance contained in the plastic waste that has been heated and melted, even if it contains a certain amount of insoluble substance, it is possible to use the plastic waste as recycled plastic. .

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings. 1 to 4 show a plastic recycling apparatus according to the first embodiment. The plastic recycling apparatus 1 has a basic configuration substantially similar to that of a normal kneading extruder, and includes a cylinder (barrel) 2 and a cylinder 2
Heating unit (heater) 3 installed on the outer periphery of the cylinder and the cylinder 2
It has a single-screw screw 4 arranged therein, a material supply unit (hopper) (not shown) arranged at the upstream end of the cylinder 2, and a drive device (not shown) for driving the screw 4. In addition to the above configuration, the plastic recycling apparatus 1 further includes a crushing section 5 arranged at the downstream end of the cylinder 2 (left side in FIG. 1).

The screw 4 is constructed by providing a spiral flight portion 8 on the outer peripheral surface of the shaft portion 7, and the distance between the outer periphery of the shaft portion 7 and the inner periphery of the cylinder 2 is set to 3 to 4 mm. Has been done. The crushing section 5 is arranged near the tip 4a of the screw 4. The crushing portion 5 is fixed to the inner cylinder 10 that is a rotating body that is attached to the screw 4 and rotates integrally with the screw 4, and is fixedly attached to the inner peripheral surface of the cylinder 2, and the outer peripheral side of the inner cylinder 10 And an outer cylinder 11 which is a fixed body arranged coaxially.

The inner cylinder 10 is mounted on the inner peripheral side in the vicinity of the screw tip portion 4a in an externally fitted shape, and integrally rotates with the rotation of the screw 4. The outer diameter of the inner cylinder 10 is formed larger than the outer diameter of the screw shaft portion 7, and specifically, is substantially the same as the inner diameter of the cylinder 2. The screw tip portion 4a located inside the inner cylinder 10 is formed in a tapered shape, and a spiral groove 4b is formed on the outer peripheral surface. The tip portion 4a has a function of further pushing the material discharged from the crushing portion 5 in the discharging direction by the rotation thereof.

As shown in FIG. 2, the inner cylinder 10 has a plurality of first grooves 13 and a plurality of second grooves 14 on its outer peripheral surface.
The first groove 13 and the second groove 14 are each formed long in the axial direction of the inner cylinder 10, and the first groove 13 and the second groove 14 are
Each of them has an arcuate concave cross-sectional shape and is alternately arranged in the circumferential direction of the inner cylinder 10. The first groove 13 and the second groove
The total number of the grooves 14 is preferably about 8 to 10 in order to secure the discharge amount.

The first groove 13 is formed at both axial end portions 1 of the inner cylinder 10.
0a, 10b is formed up to the upstream end (right side in FIG. 2) end 10a which is one end of the first groove 13 and the end 13a of the first groove 13 extends outward in the groove longitudinal direction. It is open. Therefore, the material pressure-fed in the cylinder 2 by the rotation of the screw 4 is pushed into the first groove 13 through the end opening 13a. The first groove 1
The other end 13b of 3 is formed apart from the other end of the inner cylinder 10 in the axial direction (left side in FIG. 2),
The groove does not open outward in the longitudinal direction. The depth of the first groove 13 is set to about 3 to 4 mm, and is formed so that the outer circumference of the screw shaft portion 4 and the bottom portion of the first groove 13 are substantially aligned with each other. Therefore, the material can enter the first groove 13 relatively smoothly.

The second groove 14 includes both end portions 14a in the groove longitudinal direction,
14b are both axial end portions 10a of the inner cylinder 10,
It is formed apart from 10b and does not open outward in the longitudinal direction of the groove. Therefore, the material pressure-fed in the cylinder 2 does not directly enter the second groove 14. The bottom of the second groove 14 is formed with a through hole 16 that penetrates to the inner side of the inner cylinder 10. A plurality of through holes 16 are formed in each second groove 14. Multiple through holes 16
Are arranged side by side in the longitudinal direction of the groove. The diameter of each through hole 16 is 4
It is about 5 mm.

As shown in FIG. 3, the inner peripheral surface 11 of the outer cylinder 11
A spiral groove 18 is formed in a. The groove 18 has a rectangular transverse cross-sectional shape and a groove width of 4 to 5 mm.
A shallow groove having a groove depth of about 1 mm.

As shown in FIG. 4, the inner cylinder 10 is inserted inside the outer cylinder 11 to form a crushing portion. Outer cylinder 11
A minute gap 20 is secured between (the portion other than the groove 18 of) the inner peripheral surface of 1 and the outer peripheral surface of the inner cylinder 10 (the portion other than the first and second grooves 13 and 14 thereof). . This minute gap 2
0 may be set according to the required degree of miniaturization of the insoluble substance, and is preferably about 0.2 mm, for example.

A screen (stainless wire mesh) 22 and a breaker plate 23 are provided on the downstream side of the crushing section 5, and a die plate 25 having a discharge port 24 is further provided.

A method for producing recycled plastic using the plastic recycling apparatus 1 and the like will be described below. As the plastic waste, for example, plastic waste for container packaging can be targeted.

First, as an initial treatment, a step of removing metal from a plastic waste and a step of removing adhering dust are performed. Metal removal is performed using magnetic force selection and a metal sensor. Further, the removal of adhered dust is performed by using high pressure air agitation and a cyclone. Even after initial treatment, plastic waste may contain insoluble substances such as wood chips (split chopsticks, etc.), paper, aluminum vapor deposition sheet, thermosetting resin, etc., in addition to thermoplastic resin. However, together with these insoluble substances, the plastic waste is put into the material supply section of the plastic recycling apparatus 1 as a material. A compatibilizer is added to the material. As the compatibilizer, those containing glycidyl methacrylate or N-methylolamide are preferable.

When the screw 4 in the cylinder 2 rotates, the material in the material supply section is transferred in the cylinder. Of the materials being transferred, the thermoplastic resin is heated and melted by the heating unit 3 and kneaded. It should be noted that a plurality of types of resins having different melting temperatures may be included. Even if there are plural kinds of resins, they can be melted by heating and kneaded.

The molten material is pressure-fed to the crushing section 5 by the rotation of the screw 4, and enters the first groove 13 from the end 13a of the first groove 13. The material that has entered the first groove 13 moves to the second groove 14 through the minute gap 20 between the inner cylinder 10 and the outer cylinder 11, and from the through hole 16 of the second groove 14 of the inner cylinder 10. It is ejected inward.

At this time, the grooves 13 and 14 of the inner cylinder and the groove 18 of the outer cylinder function as a rugged portion for shearing, and the shearing action of both grooves crushes the insoluble substance to make it finer and kneads it. It is dispersed in the material. Here, the insoluble substance cannot be moved from the first groove 13 to the second groove 14 through the minute gap 20 and is discharged from the crushing section 5 unless it is made fine to the size of the minute gap 20. Nor. Therefore, the insoluble substance can be surely miniaturized. In addition,
The crushing of the insoluble substance is performed in a wide area between the inner cylinder 10 and the outer cylinder 11, so that the fine processing capacity can be increased.
Moreover, in the crushing section 5, since only the insoluble substance is to be crushed and the thermoplastic resin is molten, there is almost no need to crush, and the crushing can be efficiently performed with a small force.

The material discharged from the crushing section 5 is further
It is discharged from the discharge port 24 of the die plate 25 through the screen 22 and the breaker plate 23 and cut by a cutter (not shown) to form pellets of a predetermined shape made of recycled plastic. In addition, a part of the injection molding machine may be configured by the plastic recycling device to perform injection molding with recycled plastic.

According to the present embodiment, by making the insoluble substance finer in the crushing section 5, even if a small amount of the insoluble substance is contained, the recycled plastic is acceptable in terms of quality. 1.5m thick with this recycled plastic as raw material
When a thin molded product of m (20 L poly bucket) was molded by a conventional molding machine, it was confirmed that molding could be performed without problems. In addition, as a molded product made from this recycled plastic, for example, a storage box for medical waste such as used injection needles and disposable diapers is suitable. Moreover, by making the insoluble substance finer to obtain adhesiveness with the compatibilizing agent, the insoluble substance is made into a reinforcing agent, and it is acceptable even if a certain amount of the insoluble substance is mixed in the material. In addition, since the insoluble substance that has been made fine in the crushing unit 5 is kneaded into the material, the amount of the compatibilizer added can be reduced and the cost can be reduced.

FIGS. 5 and 6 show a plastic recycling apparatus 31 according to the second embodiment. In the second embodiment, the same parts as those in the first embodiment are designated by the same reference numerals. In this plastic recycling apparatus 31, the structure of the crushing unit 5 is different from that of the first embodiment. In the second embodiment, the rotating body forming the crushing section 5 is formed on the tip 4a of the screw 4, and the fixed body forming the crushing section 5 is formed on the breaker plate 23. The tip portion 4a of the screw 4 is formed in a conical shape, and a plurality of grooves 33 are formed radially from the center of the tip.

Further, the breaker plate 23 is attached to the screw 4
As shown in FIG. 6, the surface 23a facing the tip portion 4a of the blade is circular and has a V-shaped cross section corresponding to the shape of the screw tip portion 4a so as to have a concave shape. There is. Also, a plurality of grooves 34 are radially formed on the surface 23 of the breaker plate 23 facing the screw 4. Further, breaker plate discharge holes 35 are formed between the grooves 34. In the second embodiment, the grooves 33,
34 functions as a shear uneven portion, and the screw tip portion 4a, which is a rotating body, rotates so that the groove 3 that is a shear uneven portion is formed.
The insoluble substance is finely divided by the shearing action of 3,34. The present invention is not limited to the above embodiment.

[0026]

According to the present invention, the infusible substance contained in the plastic waste that has been heated and melted is finely divided and dispersed in the molten material, so that even if a certain amount of the insoluble substance is contained. Acceptable and qualitatively acceptable recycled plastics can be produced from plastic waste.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a plastic recycling device according to a first embodiment.

FIG. 2 is a side view of an inner cylinder of a crushing section.

FIG. 3 is a cross-sectional view of an outer cylinder of a crushing section.

FIG. 4 is a cross-sectional view of a crushing unit.

FIG. 5 is a cross-sectional view of a plastic recycling device according to a second embodiment.

FIG. 6 is a plan view of a breaker plate which is a fixed body of a crushing section.

[Explanation of symbols]

1 plastic recycling equipment 3 heating section 4 screws 5 crushing section 10 Inner cylinder (rotating body) 11 Outer cylinder (fixed body) 13 1st groove (shear uneven part) 14 Second groove (shear irregularity) 18 grooves (shear irregularities)

Claims (4)

[Claims] 1. A plastic recycling apparatus for producing recycled plastic using plastic waste containing an insoluble substance as a material, the heating section heating the material, and the heating section melted by heating. And a crushing unit for crushing the insoluble substance contained in the material into fine particles, and a plastic recycling apparatus. 2. A screw for transferring the material to the crushing section, wherein the crushing section includes a fixed body and a rotating body which is rotated by a rotating force of the screw, and the fixed body and the rotating body. The plastic recycling apparatus according to claim 1, wherein the insoluble material is made into fine particles by a shearing action between them. 3. The crushing section includes at least one of an inner cylinder, an outer cylinder coaxially arranged outside the inner cylinder and rotatable relative to the inner cylinder, an outer peripheral surface of the inner cylinder and an inner peripheral surface of the outer cylinder. A shear irregularity portion formed on one surface, and the insoluble substance contained in the material sent between the inner cylinder and the outer cylinder, the inner cylinder and the outer cylinder. The plastic recycling apparatus according to claim 1 or 2, wherein the plastic recycling apparatus is configured to be sheared by the sheared uneven portion and finely divided by relative rotation. 4. A method for producing a recycled plastic using a plastic waste containing an insoluble substance as a material, wherein the plastic waste contained in the material is heated and melted and contained in the melted material. A method for producing a recycled plastic, characterized in that a recycled plastic is obtained by crushing the insoluble substance to be finely divided.