JP3857758B2 - Plastic waste material recycling molding method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a plastic waste material recycling molding method in which a waste material mainly composed of plastic is reused to form a useful molded product.
[0002]
[Prior art]
Large amounts of plastic waste from used plastic packaging containers or scrap car bumpers, battery cases, and other plastic products are polyvinyl chloride, polyethylene, polypropylene, nylon, acrylonitrile, polystyrene, polyamide, polyester, urethane, epoxy. , Various thermoplastic or thermosetting plastic materials such as phenol, or copolymer resins of these materials are mixed, and metal, wood pieces, glass pieces, fiber scraps, and other contaminants are mixed. . Conventionally, since such plastic waste materials have different melting temperatures for each material, it has been difficult to supply a plastic injection material to, for example, a known injection molding machine to form a recycled molded product. Therefore, it was considered impossible to recycle unless sorted by material.
However, since a high level of separation technology is required for separation and the cost is high, conventionally, most of such plastic waste materials are dumped in a disposal site as industrial waste. In addition, even when such plastic waste is incinerated, there is a problem that harmful gases with a strong odor are generated and the atmosphere is polluted.
[0003]
[Problems to be solved by the invention]
Therefore, the present invention provides a method that can be recycled into a useful molded product as it is without separation even with plastic waste mixed with various plastic materials, reducing the cost required for such separation, etc. It aims to promote recycling and solve the above problems.
[0004]
[Means for Solving the Problems]
For this purpose, the plastic waste recycling method of the present invention is a method in which a plastic waste material in which a plurality of types of plastic materials are mixed is loaded into a mixing device provided with blades rotating at high speed by a motor in the chamber, and the waste material is stirred. The plastic waste material is discharged from the chamber after a certain period of time after the load current of the power source reaches a peak, so that the plastic waste material is melted into a gel state by frictional heat accompanying stirring, and this is molded as it is. The molded product is formed by loading into a machine.
[0005]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a process chart of this recycling molding method. The first step a is a step in which various plastic waste materials obtained from waste are pulverized to an appropriate size to form chips, granules, or powders. And it measures (process b) in order to adjust a component according to the physical property requested | required as a molded article. At that time, if necessary, a material other than plastic (for example, rubber, wood powder, paper, fiber, etc.) may be added for the purpose of reinforcing, improving elasticity or increasing the amount. Furthermore, coloring, agents, new plastic materials, reinforcing agents, etc. can be added.
[0006]
The plastic waste thus weighed is put into the mixing apparatus 1 illustrated in FIG. This mixer 1 forms a horizontal cylindrical chamber 3 on a machine base 2, and a rotating shaft 5 supported horizontally by bearings 4 and 4 is guided to the center of the chamber 3, and one end of the rotating shaft 5 is connected to the mixer 1. The motor 7 is connected via a joint 6. The rotary shaft 5 is hollow, and a rotary joint 8 and a coupling 9 are provided at the end of the rotary shaft 5, and cooling water is supplied to a water supply pipe 10 provided at the inner center of the rotary shaft 5 through the rotary joint 8. The cooling water is reciprocated in the rotary shaft 5 and discharged from the coupling 9.
[0007]
As shown in FIGS. 2 to 4, a total of six blades 11 a to 11 f protrude from the outer periphery of the rotating shaft 5 penetrating the chamber 3. The blades 11a and 11f at both ends of the blades 11a and 11f are rotated at an angle of about 15 degrees so that the leading edges thereof are in sliding contact with the inner surfaces of both end walls 12 and 12 of the chamber 3 with almost no gap when rotated in the direction indicated by the arrows. Inclined and fixed to the outer peripheral surface of the rotary shaft 5. Further, the four blades 11b, 11c, 11d, and 11e in the middle portion are fixed in a staggered manner on the outer peripheral surface of the rotating shaft 5, and the leading end portion of each outer blade is in a direction in which the leading edge during rotation faces both ends of the chamber 3. Each is beaten at an angle of about 15 degrees.
[0008]
Further, 12 is a material supply port provided in one end wall of the chamber 3, 13 is a spiral material supply screw formed on the outer periphery of the rotating shaft 5, and 14 is a material surrounding the supply screw 13. A supply box 15 is a hopper provided above the supply box. The hopper is provided with a lid 16 that can be hermetically closed. Reference numerals 17 and 17 denote balance wheels fixed to the rotary shaft 5.
[0009]
A water passage 18 is formed in the peripheral wall of the chamber 3, a water supply pipe 19 and a drain pipe 20 communicating with the water passage 18 are disposed, and the cooling water is circulated through the water passage 18 so that the wall of the chamber 3 is formed. It can be cooled. Reference numeral 26 denotes an optical thermometer, 21 denotes an optical thermometer measuring head provided on a part of the peripheral wall of the chamber 3, and the measuring head 21 and the optical thermometer 26 are connected via a connection cable. Has been. Reference numeral 22 denotes a water passage provided so that cooling water is passed through a water supply pipe 23 and a drain pipe 24 in order to prevent the measurement head 21 from overheating. Reference numeral 25 denotes a digital panel meter that displays the temperature measured by the optical thermometer 26. Thus, by passing cooling water through the measurement head 21 to prevent overheating, the resin can be prevented from sticking to the light receiving surface, and the accuracy of the measurement temperature can be expected.
[0010]
Reference numeral 27 denotes a gel discharge door provided on the bottom wall portion of the chamber 3. The door 27 is rotatably supported by a shaft 28, and a gear 29 provided on the shaft 28 meshes with the rack 30. By moving the cylinder 28 forward and backward by the operation of the cylinder 32, the shaft 28 rotates and the door 27 can be opened and closed. Reference numeral 31 denotes a gel receiving tray disposed immediately below the door 27.
[0011]
Further, a gas vent pipe 33 is connected to one side wall of the chamber 3, and the pipe 33 is disposed in the vacuum exhaust gas device 34.
Reference numeral 40 denotes a control panel. The control panel 40 is connected to an inverter for controlling the rotational speed of the motor 7, and includes an ammeter for measuring the load current of the motor 7 and a timer. The door 27 can be opened and closed by issuing a command to
[0012]
In the mixing apparatus 1 configured as described above, cooling water is circulated in the rotating shaft 5 and the wall of the chamber 3, and the blades 11 a to 11 f are rotated at high speed via the rotating shaft 5 by the motor 7. For example, the blades 11a to 11f are rotated at a high speed so that the tip speed of the blades 11a to 11f can be increased to about 20 to 50 m / s. Then, plastic waste material crushed into chips, granules, etc. of a certain size in advance is put into the hopper 15, and the plastic waste material is supplied into the chamber 3 from the material supply port 12 by the guide of the supply screw 13, and the blades 11 a to 11 a. This is stirred from 11f.
[0013]
FIG. 6 shows the measurement with the optical thermometer 26 when the plastic waste material composed of 50% polypropylene and 50% acrylonitrile / ethylene propylene rubber / styrene copolymer resin is filled in the chamber 3 and stirred as described above. The temperature change of the plastic waste material in the chamber 3 (indicated by the symbol A) and the change in the load current of the motor 7 at that time (indicated by the symbol B) are respectively shown in a chart with the horizontal axis as the time axis. is there. As described above, the plastic waste material in the chamber 3 generates frictional heat as it is agitated, and the temperature gradually increases due to the frictional heat. When indicated by a point a in FIG. To melt. Further, the load current of the motor 7 reaches a peak at a point b in the figure, and the temperature of the plastic waste material becomes an appropriate gel state within a few seconds thereafter. By detecting the time point when the load current of the motor 7 reaches a peak in this way, it can be detected that the plastic waste material in the chamber 3 has started to melt. That is, when the plastic waste material starts to melt, the stirring resistance increases most and the load current reaches its peak at the same time. For this reason, the control panel 40 detects that the load current peaks and operates the timer to operate the cylinder 32 a few seconds later (the timer setting time varies slightly depending on the amount and composition of the plastic waste thrown in). If the plastic waste material in the chamber 3 is discharged by opening the door 27, the plastic waste material can be discharged when it is always melted into a gel state with an appropriate softness. For this reason, by taking such a discharge timing, it is possible to adjust the viscosity so that the softness is always optimum for the convenience of molding in the next molding step.
[0014]
The blades 11a and 11f prevent the molten plastic waste material from adhering to the inner surfaces of both end walls. Further, since the blades 11b to 11e guide the plastic waste material toward the center in the chamber 3 by its inclination, the plastic waste material melted in the chamber 3 can be made into a lump-like lump without being dispersed. The wall of the chamber 3 is cooled by the cooling water, and the rotating shaft 5 and the blades 11a to 11f are cooled by the cooling water circulating in the rotating shaft 5, so that the temperature difference from the molten plastic waste is sufficiently maintained. Adhesion can be prevented. Therefore, if the door 27 is opened, the plastic waste material in the gel state is discharged onto the tray 31 by centrifugal force without difficulty. (Steps c and d).
[0015]
The plastic waste discharged in this way is loaded into a molding machine (not shown) such as a pressure molding machine or an extrusion molding machine while it is in its molten state, and is in the form of a plate, rod, granule, chip, box, etc. Mold into a desired shape. (Step e). FIG. 7 shows an example of a pressure molding machine 42 composed of a lower mold 40 and an upper mold 41 for that purpose. The plastic waste material 50 melted in a gel state is loaded into the lower mold 40, and the upper mold 41 is pressed down and pressed to form the plastic waste material 50 into a plate shape.
[0016]
In this way, the plastic waste material melted by the frictional heat of stirring is immediately loaded into the next molding machine as it is without being reheated, so that the various plastic materials in the waste material can be integrated as a unitary product without separation. Can be molded. For this reason, although various plastic materials are mixed, it is possible to mold a molded product having excellent material properties such as strength and elasticity.
Incidentally, the plastic waste material having the above composition was able to obtain high properties such as a flexural modulus of 1700 kg · f / cm ² or more, a bending strength of 300 kg · f / cm ² or more, and a tensile strength of 150 kg · f / cm ² or more. For this reason, the use of the molded product is also very wide without any damage from new materials. The plastic waste material that can be recycled here is not limited to the above composition, and various waste plastic products such as automobile bumpers, automobile interior parts, PET bottles, polystyrene foam containers, chemical containers, and battery cases can be mixed and used.
[0017]
If the gas in the chamber 3 is sucked by the vacuum exhaust gas device 34 through the pipe 33, harmful gas generated as plastic waste such as vinyl chloride melts can be discharged to the outside. Can keep good. Further, by closing the lid 16 of the hopper 15 in an airtight manner and reducing the pressure in the chamber 3, the ratio of air, gas, etc. mixed into the molten resin with stirring can be reduced as much as possible. More desirable to improve.
[0018]
In this way, the plastic waste material melted by the frictional heat of stirring is immediately loaded into the next molding machine as it is without being reheated. Can be molded. For this reason, it is possible to mold materials with excellent material properties such as strength and elasticity, despite the presence of various plastic materials such as thermoplasticity and thermosetting properties, and the range of uses of the molded products is wide. .
[0019]
【The invention's effect】
As described above, according to the recycling molding method of the present invention, the plastic waste material can be melted into an appropriate gel state by frictional heat accompanying stirring, and a useful molded product can be molded by integrally dissimilar plastic materials. For this reason, plastic waste can be recycled at low cost without requiring separation, and resources can be effectively used, and it is extremely effective in solving the problem of processing plastic waste.
[Brief description of the drawings]
FIG. 1 is a process diagram of a plastic waste material recycling molding method according to the present invention.
FIG. 2 is a longitudinal sectional view of a mixer for carrying out the plastic waste recycling method according to the present invention.
FIG. 3 is an enlarged view of the blades of the mixer of FIG. 2;
4 is a plan view of FIG. 3. FIG.
5 is a cross-sectional view taken along line AA in FIG.
FIG. 6 is a diagram showing a change in temperature and a change in load current of a motor accompanying stirring of plastic waste material.
FIG. 7 is a longitudinal sectional view of a molding machine for carrying out the plastic waste recycling method of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Mixing apparatus 3 Chamber 5 Rotating shaft 11a-11f Blade | wing 12 Material supply port 42 Molding machine

Claims (1)

A plastic waste material mixed with a plurality of types of plastic materials is loaded into a mixing device provided with blades that rotate at high speed by a motor in the chamber, and the waste material is agitated. By discharging the plastic waste material from the chamber after a period of time, the plastic waste material is melted by frictional heat accompanying stirring into a gel state, and this is directly loaded into a molding machine to form a molded product. Characterized plastic waste material recycling molding method.

Images