JPH11138556A - Molding method of plastic - Google Patents

Abstract

PROBLEM TO BE SOLVED: To develop a simple molding device and a molding method, with which waste plastics such as waste PET bottles or the like are molded into lumps. SOLUTION: This method is performed by a device, in which an extruder 1 is combined with a conveyor device 7 having a large number of cavity side molds 4 installed thereon so as to fill continuously melted waste plastic material in cavities and, after being pressed with a roller-like presser 10 or without being pressed, to cool filled resin by cold air and finally discharge a molding with an ejector pin 5 annexed to the mold so as to be further cooled in a water tank, in order to mold a natural stone-shaped matter.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the reuse of waste plastic for final use.

[0002]

2. Description of the Related Art A part of waste plastic is recycled as a molding material, but most of the other flammable ones are disposed of in incineration plants and non-combustible ones are disposed of in landfills. It is the current situation. Moreover, in incineration, the heat generated by the plastic is large, which greatly reduces the service life of the incinerator.In the latter landfill, the shape of the molded product is not uniform, and it does not collapse for many years. There was a problem that the solidification of the ground was not performed and the land could not be used.

[0003]

In recent years, a large amount of PET bottles have been used as containers for seasonings and beverages, but as described above, recycling has hardly been performed. Even if a new product is formed, the new product will eventually be discarded again, eventually requiring final disposal.

[0004] Ideally, the final treatment should be assimilated into the natural environment without polluting the environment. In addition, it is natural that it is desirable that the form be used as an effective one, and it is an object to treat the waste plastic along this.

[0005]

According to the present invention, waste plastic is formed into a shape close to natural stone or crushed stone, and this is used as a substitute for natural stone such as crushed stone and ballas, on the foundation of a building, or on various machines. It is used as the basic material of the device.

[0006] In order to be used as a substitute for natural stone, it is necessary that the forming process be performed at low cost. In the present invention, an extruder is used instead of a general injection molding machine, a plurality of molds each having a cavity are continuously mounted on a conveyor, and the molten resin is continuously fed from the extruder into the cavity. And press the filled resin against the cavity surface with a separate pressing jig (roller etc.) or cool without pressing, and discharge the molded product out of the cavity with the rotation of the conveyor, The cooling is further performed in a water tank to obtain a natural stone-shaped molded product.

In the mold having the cavity formed therein, a projecting pin having a large diameter is inserted at the center of the bottom surface of the cavity in a penetrating manner from the cavity surface to the mold back surface.
The large-diameter end surface is always kept the same as the cavity surface by the bias of the spring inserted into the pin. While this mold is mounted on the conveyor and rotating, the small-diameter end of the push pin abuts against the attached roller and is pressed, protruding from the cavity surface against the bias of the spring, and the molded product is removed from the cavity. It is configured to be discharged outside.

[0008]

In the molding method according to the present invention, the molten resin continuously extruded from the extrusion molding machine is continuously filled into a plurality of molds moving in a circular shape by the conveyor, and the molding time is reduced because the mold is cooled. Be shortened. Furthermore, unlike the normal injection molding, the mold does not require the core side mold and only the cavity side mold (half mold) is used. Is inexpensive, so that molded articles can be produced at low cost.

[0009] All of the molded articles formed in the cavity of such a mold are massive, and therefore exhibit the same hydrophobic performance as natural stone when buried in the soil, It will be useful for stable solidification.

[0010]

Embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a side view showing a plastic molding apparatus according to the present invention in a partial cross section, and comprises an extruder, a nozzle thereof, a molding die, and a circulating transfer device thereof.

The extruder 1 may have a single screw or a single screw 1a, and a cylinder 1c preferably has a vent device (not shown).

A needle valve 3 for adjusting the discharge amount of molten resin is inserted in the center of the nozzle 2 mounted on the tip of the cylinder 1c so as to freely move back and forth in the direction of the nozzle hole. A fixing screw is provided.

The molding die 4 according to the present invention is a so-called half mold in which a cavity 4c for obtaining a natural stone-shaped molded product is formed, and is a so-called half mold. No mold). A protruding pin 5 having a slightly larger tip is provided on the molding die 4.
Is slidably inserted through the cavity surface from the cavity surface to the back surface of the mold, and is fitted to a spring seat 5s formed at the other end of the protruding pin 5 on the mold back surface. By the biasing of 6, the tip end surface of the pin is kept flush with the cavity surface. When the back surface of the spring seat 5s of the protruding pin 5 is pressed, the large diameter side protrudes from the cavity surface.

One edge of the mold 4 is higher than the edge 4b on the symmetrical side, and a wide edge 4a is formed to protrude outward. Although the upper surface of the wide edge 4a is not shown, it is desirable that the cross section be formed in a mountain shape for cutting the molten resin described later.

The conveyor device 7 installed immediately below the extruder moves in the horizontal direction, turns downward and returns, and is composed of a chain or a belt. Although not shown, a rotary driving device (electric motor or the like) Driven continuously or intermittently.

A plurality of the dies 4 are arranged on the conveyor device 7 over the entire periphery thereof, and the wide edges 4a of the dies are located on the downstream side of the rotation of the conveyor, and the wide edges 4a are formed.
To cover the symmetrical side edge 4b of the subsequent mold. FIG. 1 shows a conveyor device 7 formed by a chain, in which each mold is mounted on both side surfaces thereof using one pin link of the chain, but the mounting method is not limited to this. Absent.

In the vicinity of the nozzle 2 attached to the extruder, the outer peripheral surface thereof contacts the upper surface of the wide edge 4a of the mold 4 at a position downstream and above the rotation of the conveyor 7. As shown in FIG.
A pressure receiving table 9 (a roller is used in the embodiment) whose upper surface is in contact with the bottom of the mold immediately below the roller 8 is attached to a predetermined bearing (not shown) or the like of the conveyor device (FIG. 2). .

An injection device Ar (indicated by an arrow) for blowing cold air or cold water is provided further downstream of the roller 8 to cool the resin filled in the cavity.

At least the lower surface of the molten resin is formed along the inner surface of the cavity before being cooled by cold air or the like in the cavity 4c. To further shape the upper surface, as shown in FIG. The embossing roller 10 formed with several projecting surfaces 10a for pressing the molten resin P in the mold 4c is set above the conveyor 7, and is rotated at a peripheral speed synchronized with the moving speed of the mold 4, and each cavity is rotated. The inner melt may be pressed from the upper surface. In this case, it is necessary to provide a cooling water circuit inside the embossing roller 10 and cool the protruding surface 10a through the cooling water.

Further, in order to make the large-diameter end of the protruding pin of the mold protrude from the cavity surface, a pin driving roller 11 is provided on the main shaft of the downstream drive wheel 7a of the conveyor 7 or a shaft directly below the mold passage near the main shaft. Supported.

A water tank W is provided below the conveyor device 7. The molded product discharged from the mold falls into the water tank, and is further sufficiently cooled. The mold from which the molded product has been discharged is circulated by a conveyor.
During the return of the mold, that is, the nozzle 2 of the extruder 1
An injection device (indicated by an arrow in FIG. 1) for spraying cooling water onto the cavity surface to perform cleaning and cooling is mounted under the conveyor until immediately below the conveyor.

The plastic molding apparatus of the present invention has the above-described structure, and a unique molding is performed by a half mold. The embodiment will be described below.

[0023]

[Embodiment] An equal amount of crushed pellets of a PET resin crushed from a used PET bottle and a phenol resin molded product (printed circuit board) which is a thermosetting resin was captured by an electric dust collector installed in an incinerator of municipal solid waste. What mixed 10% of ash was used as the molding material.

A nozzle 2 having a nozzle hole diameter of 6 mm at the tip was mounted on an extruder having a screw diameter of 60 mm, and the above-mentioned material was melt-kneaded at a cylinder temperature of 200 to 300 ° C. to extrude a molten resin. In this case, the needle valve 3 did not limit the discharge amount from the nozzle.

The cavity is engraved with a semicircular cross section having a radius of 9 mm, a length of 30 mm and a depth of 15 mm.
The outer dimensions of the mold 4 are 40 × 40 × 25, and the wide edge 4a
Was 15 mm in width. Further, the projecting pin 5 having the large diameter at the tip is inserted through the center of the cavity from the cavity side to the back surface, and a spring 6 is fitted to the outside of the projecting pin. Was formed. As a result, the surface of the large-diameter portion at the tip of the pin 5 is kept flush with the cavity surface. This mold was supported by a chain conveyor 4d (FIG. 2) without interruption on a chain conveyor in which the distance between the drive shafts 7c, 7c was 1 m.

The resin melt-kneaded under the above-mentioned molding conditions was extruded without interruption into the mold while the conveyor having the mold attached was driven at a constant speed. The resin is loaded not only on the cavity but also on the wide edge 4a. This wide edge 4a
The upper molten resin is rolled and cut by the contact rotation between the cutting roller 8 and the wide edge 4a. In addition, when the cavity 4c arrives immediately below the nozzle, the rotation of the conveyor 7 is stopped for a predetermined time, and when the cavity is filled with the molten resin, the molding may be performed by so-called intermittent driving, in which the molding is re-driven. is there.

Thereafter, the mold 4 is rotated by the conveyor 7, and the resin reaches the pin driving roller 11 while being cooled by the cool air jet device Ar, and protrudes from the roller 11 and the end face of the lower end of the pin 5 on the spring seat 5 s side. Gets up and the pin goes up. As a result, the molded product in the cavity is discharged. In addition, when it was pressed from the upper surface of the cavity by the embossing roller 10 before the discharge, a molded product with a glossy surface was obtained.

The molded article is cooled in a water tank W immediately below,
The mold is further cooled by the cooling water injection device C, and proceeds under the nozzle of the extruder to be refilled with the molten resin.

In the molded product manufactured by the above-described molding process, the surface in contact with the cavity had a shape obtained by transferring the cavity, and the upper surface was porous. However, not only dust ash but also thermosetting resin crushed pieces are made of thermoplastic PET.
It was not covered with the resin and was not exposed.

[0030]

The plastic molding apparatus according to the present invention has a low equipment cost and can be manufactured continuously, so that a molded product can be obtained at a low cost.

On the ground, it is possible to knead a polluting substance into plastic and form it into a lump at low cost, so that this molding method can be used for permanent treatment of burying underground as a substitute for natural stone. .

A dissolution test was performed on the molded article intended to be buried underground, but no pollutant was eluted. It is necessary to observe the long-term progress of the solidification stability of the ground, but there is no problem at present three months after the burial.

[Brief description of the drawings]

FIG. 1 is a side view showing an outline of a molding apparatus according to the present invention in a partial cross section.

FIG. 2 is a front view showing a partial cross section of a rolling and cutting roll device for cutting a molten resin continuously placed on an upper edge of a mold.

FIG. 3 is a side view showing a cross section of a pressing roller for pressing a molten resin filled in a cavity.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 Extrusion molding machine 2 Nozzle 3 Needle valve 4 Mold for molding 5 Protruding pin 6 Spring 7 Conveyor device 8 Roller for resin cutting 9 Pressure receiving table 10 Press roller 11 Roller for pin driving

Claims (2)

[Claims] 1. A conveyor equipped with a plurality of (female) molds on a cavity side is continuously or intermittently rotated, and a molten resin extruded from an extruder is continuously filled in the mold cavities. Then, the filled resin is pressed into the cavity or cooled without being pressed, and the protruding pin formed in the mold and inserted into the mold is provided with the protruding end surface on the back side of the mold for driving the pin in the conveyor device. A plastic molding method characterized by discharging the cooled resin by bringing the pin into contact with a roller and projecting the pin from the cavity to the upper surface. 2. A protruding pin having a slightly large diameter at the center of a cavity of a female mold is inserted through the cavity surface from the cavity surface to the mold rear surface, and is biased by a spring fitted to the pin. 2. The plastic molding method according to claim 1, wherein the tip surface is a mold held on the same plane as the cavity surface.