JP2001101940A - Method and apparatus for recycling covering material of electric cable - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a recycling method and recycling apparatus for obtaining recycled product by a process, that is, an apparatus from waste material of covering part of electric cable after cutting cross-links by means of mixing fusion of cross-linked polyethylene. SOLUTION: In two axial screw extrusion machine (10), the recycling method and recycling apparatus of covering material of electric cable of this invention comprises a mixing fusion part (17) with at least 24.5 times diameter of screw (16) on the upstream of a volatilization hole 13, a cooling part (18) with at least 7 times the diameter of switch (16) on the downstream of the above volatilization hole, and a molding apparatus directly connected to the front end, thereby melting waste material of covering part of electric cable is volatilized, cooled and pressed directly to the molding apparatus.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for recycling an electric wire covering material, that is, a crosslinked polyethylene, and further relates to a method and an apparatus for directly shaping a crosslinked polyethylene waste material into a recycled product.

[0002]

2. Description of the Related Art In general, crosslinked polyethylene is flexible without adding a plasticizer, does not become brittle even at low temperatures below freezing, and has a low product price. Used as a coating. However, when used for a long period of time in a natural environment where the climate and weather change, the coating material is weathered and deteriorated, and the function as the coating material is deteriorated. Through such replacement, a large amount of used electric wire is generated and becomes waste. However, the metal material constituting the electric wire is easy to regenerate, and has been reused or recycled. However, the crosslinked polyethylene of the coating material has almost no melt flowability as it is, and it is difficult to recycle and reuse it. Therefore, most of the crosslinked polyethylene as the coating material is discarded, landfilled or incinerated, and it is desired to recycle and reuse, that is, recycle.

[0003] The recycling method and the recycling apparatus for crosslinked polyethylene, which are partially performed, firstly, mechanically separate the coating material from the waste electric wire. Next, the separated coating material is pulverized by a pulverizer. Next, the pulverized coating material is mechanically cut by a kneading extruder to form crosslinks, and is granulated into pellets by a granulator. Next, the pellet is formed into a product by a forming apparatus. Through the processing steps described above, waste crosslinked polyethylene is recycled and processed into a recycled product.

[0004]

The conventional method and apparatus for recycling a wire covering material have the following problems because they are configured as described above. That is, in the conventional kneading extruder, the cross-linking of the cross-linked polyethylene was mechanically cut, and the viscosity was greatly reduced. For example, in normal sheet molding, the viscosity coefficient MI is 10 to 1
Molding is possible in the range of 00 (g / 10 minutes), but the viscosity falls below this upper limit. Therefore, it is difficult to continuously form a low-viscosity state after kneading and melting. First, granulation must be performed by a granulating device provided at the tip of a kneading extruder. That is, a kneading extruder provided with a granulating device and a molding device are individually required until a regenerated product is obtained from a waste material of the wire covering material.

[0005] The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to reduce the amount of waste materials for electric wire covering materials.
It is an object of the present invention to provide a recycling method and a recycling apparatus for obtaining a recycled product in one step, that is, one apparatus.

[0006]

SUMMARY OF THE INVENTION According to the present invention, there is provided a method of recycling an electric wire covering material, which comprises melting and kneading waste materials of the electric wire covering material, devolatilizing, and cooling the mixture in a twin-screw kneading extruder. Is a method of extrusion molding to a molding device directly connected to the downstream of the apparatus. Further, the recycling apparatus of the wire covering material according to the present invention is a twin-screw kneading extruder in which at least 24.
A kneading / melting section having a length of 5 times is provided, a cooling section having a length of at least 7 times the diameter of the screw is provided downstream of the devolatilization hole, and a molding device is directly connected to the tip. It is a device provided.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a method and an apparatus for recycling wire covering materials according to the present invention will be described in detail with reference to the drawings. FIG. 1 is a cross-sectional view in the axial direction of a twin-screw kneading extruder constituting a main part of an electric wire covering material recycling apparatus according to the present invention. In FIG. 1, what is indicated by reference numeral 10 is a twin-screw kneading extruder 10, which comprises a long cylindrical cylinder 11 (only the upper part is shown in FIG. 1). And two screws 16 rotatably inserted into the inner hole of the cylinder 11. FIG. 1 is a configuration diagram viewed from the side, and shows only one screw 16 on the front side of the screws 16 arranged in parallel.

The cylinder 11 has a raw material inlet 12 on the upper surface of the upstream end portion on the left side of the drawing, a devolatilization hole 13 on the upper surface of the intermediate portion,
Each is provided. A suction devolatilizer (not shown) is connected to the devolatilization hole 13. The cylinder 11
A not-shown forming device, for example, a sheet forming die, is connected to the front end opening 14. The cylinder 11
Is provided with a temperature control device (not shown) over the entire length, and is configured to be able to set a different temperature for each section of the cylinder 11.

In the screw 16, screw pieces such as a full flight screw 21 for transporting raw materials, a kneading screw 22 for mixing and kneading raw materials, a reverse flight screw 23, and a seal ring 24 for sealing are appropriately arranged in the axial direction. It is configured in combination. The seal ring 24
Is provided on the upstream side immediately before the devolatilization hole 13, and the screw 16 is formed of a screw piece mainly composed of kneading on the upstream side from the devolatilization hole 13 to the material input port 12. The downstream side up to the tip is composed of transport-oriented screw pieces. Note that the upstream end of the screw 16 is connected to a rotation driving device (not shown).

Further, the twin screw kneading extruder 1
As 0, the cylinder 11 from the devolatilization hole 13 to the raw material inlet 12 is temperature-controlled so as to heat the raw material in the inner hole, and forms a kneading / melting unit 17. The cylinder 11 from the devolatilization hole 13 to the tip
The temperature is controlled so as to cool the raw material in the inner hole, and constitutes a cooling unit 18.

The method of recycling the wire covering material by the recycling apparatus configured as described above will be described below. That is, each section of the cylinder 11 is adjusted to an appropriate predetermined temperature by the temperature adjustment device, and
Is sucked into the suction devolatilizer, and the screw 16 is separated from the waste electric wire in the twin-screw kneading extruder 10 which is rotationally driven at a predetermined rotation speed by the rotary driving device.
The coating material made of the crushed crosslinked polyethylene is supplied to the cylinder 1 through the raw material input port 12 of the twin screw kneading extruder 10.
1 into the inner hole.

The coating material supplied to the twin-screw kneading extruder 10 is sequentially moved downstream, that is, to the tip opening 14 via the devolatilization hole 13 by the transport action of the screw 16. In the kneading and melting portion 17 from the raw material inlet 12 to the devolatilizing hole 13, the coating material is kneaded and melted by the kneading screw piece of the screw 16 while being heated from the cylinder 11. By the kneading, the coating material is mechanically cut in the cross-linking chain, the viscosity is reduced in a molten state, and fluidity is generated.

The coating material in the molten state that has passed through the kneading and melting section 17, that is, has passed through the seal ring 24, immediately passes through the devolatilization hole 13, and the volatile components are sucked and exhausted. Next, in the cooling section 18 up to the tip opening 14, the coating material is transported to the tip opening 14 by the screw piece for transport of the screw 16 while being cooled from the cylinder 11. The cooling increases the viscosity of the coating material by cooling, so that the coating material has an appropriate viscosity for molding. Thereafter, the coating material is extruded from the tip opening 14 into a sheet forming die, and a polyethylene sheet of a formed product is continuously produced from the sheet forming die.

[0014]

EXAMPLE TEX65αII-42PW-V (69 mm in diameter of screw) manufactured by Nippon Steel Works Co., Ltd. was used as a screw-type twin-screw kneading extruder 10, and a crosslinked polyethylene coating of a waste wire pulverized to a particle size of about 2 cm or less was used. A test was conducted to recycle the material. The operation data during the test processing is shown in Table 1 below, and the viscosity coefficient MI with respect to the rotation speed in the data is shown in Table 1.
2 is shown in FIG. As a result of the test, in an operation up to a processing capacity of 300 kg / h, the viscosity that enables continuous molding to kneading and melting (in the case of the test,
At a processing capacity of 300 kg / h, an MI of 43) was obtained.

[0015]

[Table 1]

In Table 1, C1 to C12 are shown in FIG.
2 shows the positions of C1 to C12 of the cylinder 11 shown in FIG. In the kneading and melting sections 17 from C2 to C9, the temperature of the cylinder 11 is adjusted to a heated state in each section. In the cooling units 18 from C10 to C12, the temperature of the cylinder 11 is set so as to cool the coating material in a molten state in each section. The screw type twin-screw kneading extruder 10 used in this test has a cylinder 10, that is, a screw 16 having a total length of 42 times the diameter of the screw 16. The length of the kneading and melting portion 17 is the same as that of the screw 1 except for the constituting cylinder portion.
The cooling unit 18 is 24.5 times the diameter of the screw 6 and the cooling unit 18 is 7 times the diameter of the screw 16.

First, the temperature of each section of the cylinder 11 was initially set to the temperature of the test No., and then the operation was performed to obtain the test results in columns 1 to 4 and 5. As a result of the test, in the twin-screw kneading extruder 10 configured as described above, by performing sufficient kneading and melting and sufficiently adjustable cooling, it is possible to continuously form the kneading and melting. It has been confirmed that a viscosity that enables the following is obtained.

FIG. 2 shows the relationship between the rotational speed of the twin-screw kneading extruder 10 and the viscosity coefficient MI in the data shown in Table 1. From this graph, the change is linear, indicating that the test was successful. Further, since the inclination of the graph is gentle, the configuration of the twin-screw kneading extruder 10 used in this test is as follows.
This shows that a viscosity that enables continuous molding after kneading and melting can be obtained over a wide range of rotation speeds.

[0019]

The method and apparatus for recycling wire covering materials according to the present invention are configured as described above, so that the following effects can be obtained. That is, by the recycling device according to the present invention, it is possible to cut the cross-linking by kneading and melting, to obtain a viscosity after kneading and melting, and to obtain a viscosity that enables molding continuously to kneading and melting.
Granulation is no longer necessary, and continuous molding from kneading and melting has become possible. Therefore, a kneading extruder and a molding device are not individually required until a regenerated product is obtained from the waste material of the wire covering material, and the regenerated product can be obtained from the waste material in one step, that is, by one device.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view in the axial direction of a twin-screw kneading extruder that constitutes a main part of a wire coating material recycling apparatus according to the present invention.

FIG. 2 shows a viscosity coefficient M with respect to the number of rotations in the data of Table 1.
6 is a graph showing a change in I.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Twin screw-type kneading extruder 11 Cylinder 16 Screw 17 Kneading / melting part 18 Cooling part

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) B29K 105: 24 B29K 105: 24 (72) Inventor Hiroaki Shintani 1-6-1, Funakoshi-minami, Aki-ku, Hiroshima-shi, Hiroshima Stock (72) Inventor Nobuhisa Kobayashi 1-6-1, Funakoshi-minami, Aki-ku, Hiroshima City, Hiroshima Prefecture Inside Japan Steel Works, Ltd. (72) Inventor Kazuyuki Nakamura 1-6-1, Funakoshi-minami, Aki-ku, Hiroshima City, Hiroshima Prefecture No. 1 F Term in Japan Steel Works, Ltd. (Reference) 4F207 AA04 AA50 AK01 KA01 KA17 KK13 KK44 KL04 KL22 KL41 KL99 KW41 4F301 AA13 AC17 BA01 BA02 BA21 BC13 BC26 BC36 BC38 BE11 BE29 BF12 BF16 BF31

Claims (2)

[Claims] 1. In a twin-screw kneading extruder (10), waste materials of an electric wire coating material are melt-kneaded, devolatilized, cooled, and extruded to a molding device directly connected downstream of the kneading extruder. A method of recycling an electric wire covering material. 2. In a twin-screw kneading extruder (10), a kneading and melting section (17) having a length at least 24.5 times the diameter of the screw (16) is provided upstream of the devolatilization hole (13). ), A cooling unit (18) having a length of at least seven times the diameter of the screw (16) is provided downstream of the devolatilization hole (13), and a forming device is directly connected to the tip of the cooling unit (18). An electric wire covering material recycling apparatus, characterized in that: