JP3145683B2 - How to increase the bulk density of waste plastic - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to sheets, films, bags, bottles, and the like, which are disposed of as general wastes such as household garbage and disposed of as business wastes from factories, supermarkets, department stores, and companies. The present invention relates to a method for increasing the bulk specific gravity of a waste plastic article having a relatively small thickness and processed into various shapes by granulation.

[0002]

2. Description of the Related Art In recent years, waste plastic processed into various shapes with relatively thin wall thickness such as styrene foam, sheet, film, bag, bottle, etc., which is discarded as general waste or business waste. Articles have been recycled as raw materials for plastics, processed into molded articles such as rods and piles, and used as raw materials for recycled solid fuels and recycled oils. To promote such resource reuse, plastic waste has been discriminated and collectively collected. If there are many containers such as bottles, the average specific gravity of the discarded plastic articles may be somewhat reduced by crushing with a roller press,
It was very small, about 0.03 to 0.07.

[0003] Transporting with the above specific gravity not only has poor transport efficiency and adversely affects the cost of recycled products, but also makes it difficult to handle in the next step and transport on a conveyor or the like. there were. Attempts to cut and mass transport were also made, but only slightly increased transport volume.
Only by cutting, the bulk specific gravity (weight per volume including voids) is still small, and a significant improvement in transport efficiency cannot be achieved. In addition, when cut, there is a risk that it will be scattered by wind during transportation or storage, and management is difficult.

[0004] Therefore, a melting device called an agglomerated granulator has been developed. The device rotates a plurality of horizontal blades at high speed at the bottom in a cylindrical container, puts plastic waste into it, cuts it, and melts it by frictional heat. It was supplied and finally turned into granules.

[0005]

However, this granulator has a small processing capacity in a batch system and a high running cost. In addition, plastic materials have different melting temperatures depending on the material, so that it is difficult to operate, there is a problem that a certain amount of molten material cannot be obtained, or if the operation method corresponding to the plastic material is not well known, operation becomes impossible. . The present invention has been proposed in view of the above, and a large amount of processing is required to continuously form plastic waste such as sheet, film, bag, and bottle into granules having a large bulk specific gravity. Depending on the purpose of reuse, granulation can be performed even when various materials are mixed, and it can be easily transported by a conveyor, etc., and storage space can be reduced. It is an object of the present invention to provide a method for increasing the bulk specific gravity of waste plastic, in which a pressing roller of a machine can efficiently take in a crushed material while preventing slipping and efficiently produce a granular material.

[0006]

In order to achieve the above object, a method for increasing the bulk specific gravity of waste plastic according to the first aspect of the present invention includes a method for increasing the bulk specific gravity of a waste plastic such as a sheet, a film, a bag, and a bottle. A coarse crushing process for coarsely crushing waste plastic articles processed into various shapes with a relatively small thickness, and a foreign matter removing process for removing material other than plastic materials such as metal caps as foreign matter by a sorting machine. A pulverizing step of pulverizing a plastic article from which foreign matter has been removed by a pulverizer, a drying step of drying the pulverized material, a horizontal rotating cylinder having a large number of die holes in a peripheral wall, and rolling along the inner surface of the peripheral wall in the inside thereof. And a granulating step of continuously supplying the dried pulverized material of the plastic material to a pellet mill granulator composed of a moving intruding roller and continuously producing granules. Since the granulator is characterized by forming a large number of grooves on the outer peripheral surface of the pushing roller, pulverized plastic material from which foreign matter has been removed and dried can be obtained without resorting to melting. Even if various materials remain mixed or the materials are unified for mainly compacting and granulation (may be partially melted due to mutual adhesion by compaction) by the pellet mill granulator Stable and continuously large bulk specific gravity (for example, 0.03 to
It is formed into granules (of about 0.07 to about 0.25 to 0.45) and processed in a large amount. The granular material can be easily transported by a conveyor or the like, and the storage space can be reduced. Further, at the time of granulation, a large number of grooves on the outer peripheral surface of the pushing roller can prevent slipping and efficiently take in the pulverized material, so that a granular material can be efficiently manufactured. Preferably, in the drying step, the pulverized material is dried such that the moisture content of the pulverized material is about 5% on average with respect to the total weight of the pulverized material.

According to a second aspect of the present invention, there is provided the method for increasing the bulk specific gravity of waste plastic according to the first aspect, further comprising a cooling step of cooling the granulated granules after the granulating step, In the next step, it can be transported on a conveyor or the like so that it can be immediately mixed with another material and regenerated.

[0008]

[0009]

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of a method for increasing the bulk specific gravity of waste plastic according to the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a flowchart of a process of a method for increasing the bulk specific gravity of waste plastic according to one embodiment of the present invention, FIG. 2 is a side view of a grinding rotor of a grinding machine used in a grinding process of the same method, and FIG. It is a principal part perspective view for explanation of the granulator used for the granulation process of the method.

As shown in FIG. 1, it is reused as a raw material for plastics such as pellets, is processed into molded articles such as rods and piles, is used for solid fuel or oil conversion, and is used for pet waste. The method of increasing the bulk specific gravity by making plastic granules that can be mixed into cat sand as a processing material,
Sheets, films, bags, bottles, etc., processed into various shapes with a relatively small thickness, and have a bulk specific gravity of 0.03-0.
A crushing step 11 for roughly crushing about 07 plastic articles W by a crusher 12, a foreign matter removing step 13 for removing material other than plastic materials such as a metal cap of a bottle as foreign matter by a sorter 14, and a foreign matter removal. A pulverizing step 15 for pulverizing the pulverized plastic article with a pulverizer 16 and a drying step 1 for drying the pulverized material to an average of about 5% by weight in a drier 18
7, a granulating step 19 of continuously supplying a dried pulverized plastic material to a granulator 50 to continuously produce granules having a bulk specific gravity of about 0.25 to 0.45; And a cooling step 21 for cooling at 22.

In the crushing step 11, the plastic waste W
Is crushed to about several tens cm by a crusher 12 which rotates a helical rotating body having a number of blades provided at intervals on an outer peripheral edge in a casing having a lattice-shaped fixed blade at the bottom. The material is decomposed and the plastic material and the non-plastic material are separated, and the metal cap part is separated in the bottle. The sorter 14 used in the foreign matter removing step 13 includes a sorter that sorts by weight and size, such as a vibrating wire mesh sieve having a mesh and a rotating roller sorter, a magnetic separator, an Arimi separator, a stainless steel separator, and the like. Combined with a sorting machine that sorts materials with different materials, using magnetic force for magnetic metal foreign matter other than plastic materials such as bases, crowns, corner fittings, etc., and using magnetic field repulsion for non-magnetic metal foreign matter And can be accurately selected and excluded.

In the crushing step 15, the crushed material from which the foreign matter has been removed is crushed by the crusher 16 into a crushed material having a size of about 25 mm square or less. As the crusher 16, for example, there is a crusher using a crushing rotor R shown in FIG. The crushing rotors R are provided in pairs so as to be driven to rotate at different speeds from top to bottom at different speeds. The crushing rotors R are axially shifted so as to mesh with each other, and are bolted to the rotating shaft via a key. Blades 26 (halves) and spacing pieces 30 alternately mounted by
(Dichotomy). The shearing blade 26 has bolts to which a shearing blade C supported by a rear portion 26A is attached to six recesses 27 in the outer peripheral portion by bolts. Since the shearing blades C of the opposing crushing rotor R are close to each other on the side surface, it is necessary to secure an accurate position.
However, a groove 37 ′ that fits into the projection 37 is formed on the shearing blade C. A ring 36 </ b> A having teeth formed thereon for performing shearing based on a difference in peripheral speed from the approaching edge of the opposing shear blade C is attached to the outer peripheral portion of the spacing piece 30.

In the drying step 17, a horizontal or oblique kiln type dryer using hot air is used as the dryer 18 to dry the pulverized material so that the moisture content becomes an average of about 5% by weight with respect to the whole. Is done. In the next granulation step 19, the dried pulverized plastic material is continuously supplied to the granulator 50, and is mainly consolidated without relying on melting (of course, it is partially melted for mutual adhesion by consolidation). May occur). Granules are produced continuously. Even if various materials of the plastic material remain mixed due to the consolidation, even if the materials are unified, the bulk specific gravity is stably and continuously large (for example, from about 0.03 to 0.07 to about 0.25 to 0.25). 0.4
It is formed into granules (about 5) and processed in a large amount. The use of granules facilitates transportation by a conveyor or the like, and can reduce the storage space.

As a granulator, there is a pellet mill 50 as shown in FIG. 3, which is rotatably supported in a horizontal state and is rotatably driven as shown by an arrow Y1. A dried pulverized material is supplied as shown in Y2. In the ring 51, 2
The rolling wheels 52, 52 of the pushing rollers are rolled in the direction of the arrow Y3, the mixture is collected in the rear space S in the direction of rotation, and compressed by the rolling wheels 52 to form a die forming the peripheral wall of the ring 51, for example. It is compacted and extruded from many die holes 53 having a diameter of 5 mm. When it is extruded by about 5 to 7 mm, it is cut by a cutter blade 54 provided outside the ring 51 to obtain a granular material. Rolling wheel 5
A large number of grooves are formed on the outer peripheral surface of 2 to prevent slippage of the pulverized material and facilitate the incorporation.

The granular material may be cooled by natural cooling.
In the next step, a cooling step 21 for cooling the granular material after the granulation step 19 is prepared in order to immediately mix with another material to start the regenerating process or to transport by a conveyor or the like. The granular material G is cooled by cold air from a refrigerator or cooler as the cooler 22, or is cooled by water cooling. Each of the above steps 11 and 2
The material treated in 1 is sent to the next step by a transport device such as a belt conveyor or a wind conveyor. After the processing in each step is performed, it can be temporarily stored in a silo. The silo is equipped with a device to prevent bridging, and the silo outlet can be connected to an automatic meter when mixing with other materials.

[0017]

As is apparent from the above description, according to the method for increasing the bulk specific gravity of waste plastic according to the first aspect of the present invention, it is possible to compare sheet-like, film-like, bag-like, bottle-like, etc. Crushing process of coarsely crushing waste plastic articles processed into various shapes with thin wall thickness, crushing process of removing material other than plastic materials such as metal caps as foreign material with a crusher, Pulverizing the removed plastic article with a pulverizer, a drying step of drying the pulverized material, a horizontal rotating cylinder having a number of die holes in the peripheral wall, and rolling along the inner surface of the peripheral wall in the inside thereof. And a granulating step of continuously supplying the pulverized material of the dried plastic material to a pellet mill granulator comprising a pressing roller and continuously producing granules. The machine is characterized in that a large number of grooves are formed on the outer peripheral surface of the pushing roller, so that the crushed material of the plastic material from which the foreign matter has been removed and dried can be pellet milled without relying on melting. Mainly compacted by the granulator to granulate (may be partially melted due to mutual consolidation during compaction). Even if various materials remain mixed, even if the materials are unified, stable It is continuously formed into a granular material having a large bulk specific gravity (for example, about 0.03 to 0.07 to about 0.25 to 0.45) and is processed in a large amount. The granular material can be easily transported by a conveyor or the like, and the storage space can be reduced. Further, at the time of granulation, a large number of grooves on the outer peripheral surface of the pushing roller can prevent slipping and efficiently take in the pulverized material, so that a granular material can be efficiently manufactured.

According to a second aspect of the present invention, there is provided the method for increasing the bulk specific gravity of waste plastic according to the first aspect, further comprising a cooling step of cooling the granulated material after the granulating step. Therefore, in the next step, the material can be immediately mixed with another material and transported by a conveyor or the like so as to start the regeneration process.

[0019]

[0020]

[Brief description of the drawings]

FIG. 1 is a flowchart of steps of a method for increasing the bulk specific gravity of waste plastic according to one embodiment of the present invention.

FIG. 2 is a side view of a pulverizing rotor of a pulverizer used in a pulverizing step of the method.

FIG. 3 is a perspective view for explaining a main part of a granulator used in a granulating step of the method.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 System for increasing bulk specific gravity of waste plastic 11 Crushing step 12 Crusher 13 Foreign matter removing step 14 Sorter 15 Crushing step 16 Crusher 17 Drying step 18 Dryer 19 Granulation step 21 Cooling step 22 Cooler 50 Granulator (Pellet mill) 51 Horizontal rotating cylinder (ring) 52 Push-in roller (rolling wheel) 53 Die hole G Granular material W Plastic waste

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-10-244536 (JP, A) JP-A-9-170009 (JP, A) JP-A-10-86155 (JP, A) JP-A-10- 225932 (JP, A) JP-A-10-296225 (JP, A) JP-A-10-211444 (JP, A) JP-A 9-234455 (JP, A) JP-A 8-216149 (JP, A) JP-A-10-46165 (JP, A) JP-A-10-235645 (JP, A) JP-A-10-225675 (JP, A) JP-A-6-320112 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) B09B 3/00-5/00 B29B 9/00 B29B 17/00-17/02

Claims (3)

(57) [Claims] 1. A crushing step of coarsely crushing a waste plastic article processed into various shapes with a relatively small thickness, such as a sheet, a film, a bag, and a bottle, using a crusher. A foreign matter removing step of removing material other than plastic materials as foreign matter by a sorter, a pulverizing step of pulverizing a plastic article from which foreign matter has been removed by a pulverizer, a drying step of drying the pulverized material, and a large number of dies on a peripheral wall. Pulverized dried plastic material is continuously supplied to a pellet mill granulator consisting of a horizontal rotating cylindrical body having holes and a pushing roller that rolls along the inner surface of the peripheral wall inside the cylindrical body, and continuously granulates. In the method for increasing the bulk specific gravity of the waste plastic, which comprises the granulating step of producing the granules, the granulator has a large number of grooves formed on the outer peripheral surface of the pushing roller. A method of increasing the bulk specific gravity of waste plastic. 2. The method according to claim 1, further comprising a cooling step of cooling the granulated granules after the granulating step. 3. The method according to claim 1, wherein in the drying step, the pulverized material is dried such that the moisture content of the pulverized material is about 5% by weight based on the total weight of the pulverized material.