JP2002240037A - Method for reusing plastic parts, plastic raw materials and plastic molded parts produced using the method - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To provide a method capable of obtaining a high-quality recycled product, having a wide range of uses of the recycled product, and reusing waste plastic at a high rate. SOLUTION: The same parts made of plastic having the same composition are separated and collected from discarded products, and the separated and collected plastic parts are crushed, melted, molded and reused.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for separating and recovering plastic parts from discarded products for reuse, and a plastic raw material and a plastic molded part produced from discarded plastic parts.

[0002]

2. Description of the Related Art Due to the high degree of freedom in design, the ability to impart various characteristics, the durability and resistance to deterioration, etc., office appliances such as refrigerators, washing machines, televisions, etc., printers, personal computers, fax machines, etc. 2. Description of the Related Art Plastic components are used in large quantities in equipment for use or toys.

[0003] In many cases, plastic parts are produced using crude oil as a basic raw material, and effective utilization of such limited resources has recently been strongly demanded. Reuse of waste is an important and urgent issue due to environmental destruction such as global warming and acid rain, environmental pollution such as generation and scattering of dioxin, and shortage of garbage incineration plants. Under such circumstances, the Home Appliance Recycling Law is scheduled to take effect in April this year.

In view of the above, various methods of recycling plastic parts have been proposed. Most of the conventionally proposed recycling methods involve roughly grasping the composition of plastic parts, separating the parts, and reusing them. However, no consideration was given to the deterioration of the composition due to the difference in the use environment of the plastic parts or the deterioration of the appearance quality such as discoloration or fading. For this reason, the quality of molded parts made of waste plastic parts as raw materials (hereinafter, may be simply referred to as “recycled products”) is low, and their usable applications are limited.

[0005] In order to improve the quality of recycled products, for example, Japanese Patent Application Laid-Open No. 2000-159900 proposes that a recycled material be mixed with a virgin material and used.
According to this method, the quality of recycled products is certainly improved, but in order to obtain high quality, the ratio of virgin raw materials must be increased. Was not along.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of such conventional problems, and an object of the present invention is to provide a method of reusing a plastic part capable of obtaining a high-quality recycled product. It is assumed that.

Another object of the present invention is to provide a method in which recycled plastics can be reused at a high rate with a wide range of applications in which recycled products can be used.

It is a further object of the present invention to provide high quality plastic raw materials and plastic molded parts made from waste plastic.

[0009]

According to the present invention, the same parts made of plastic having the same composition are separated and collected from discarded products, and the separated and collected plastic parts are pulverized, melted, molded, and reprocessed. There is provided a method of recycling a plastic part characterized by utilizing.

Here, the plastic part is preferably made of a thermoplastic resin from the viewpoint of ease of reuse.

From the viewpoint of further improving the quality of the recycled product, it is preferable to further separate the plastic component depending on the presence or absence of surface decoration and / or the color tone of the plastic component.

It is preferable that the discarded product is a washing machine from the viewpoint of easy separation and collection of plastic parts.

Further, according to the present invention, there is provided a plastic raw material characterized by being produced by pulverizing, melting and molding the same parts made of the same composition of plastic, which are separated and recovered from discarded products.

Further, according to the present invention, there is provided a plastic molded part characterized by being produced by crushing, melting and molding the same part made of plastic having the same composition, which is separated and recovered from a discarded product. .

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION The inventors of the present invention have conducted intensive studies as to whether the recycle rate of discarded plastic parts can be increased and the quality of molded parts made of discarded plastic can be increased, and as a result, the same composition is obtained. The present invention has been made based on a new finding that even a plastic part has a completely different deterioration state depending on the place where it is used in the product.

That is, even if plastic parts have the same composition, exterior parts which are directly exposed to sunlight or rain and wind have a high degree of deterioration, while interior parts have a low degree of deterioration. Therefore, if these are mixed and reused, a high-quality recycled product cannot be obtained. Therefore, in the recycling method of the present invention, the same parts made of plastic having the same composition are separately collected from discarded products and reused. FIG. 1 is a process chart showing an example of the recycling method of the present invention.

In the process diagram of FIG. 1, first, a discarded product is disassembled (step S101), and plastic parts having the same composition are separated and collected for each part (step S1).
02). Here, the same composition means, for example, that the classification of polypropylene resin, polyethylene resin, polystyrene resin, thermoplastic polyester resin and the like is the same, and the same component means a member having the same function and effect, For example, it means a lid, a washing tub, a dehydration tub, a housing, and the like. Next, the separated and collected plastic parts are crushed into several mm to several cm (step S103). Then, the pulverized and pulverized plastic is melt-kneaded using an extruder (step S104) to form pellets (step S105). The extruder used here is a single screw extruder,
Either a twin-screw extruder or a multi-screw extruder may be used. In order to prevent the deterioration of the plastic, the heating temperature of the extruder is from the melting temperature of the plastic (T) to (T + 120).
C) is desirable. Any of sheet cutting, strand cutting, hot air cutting, under water cutting, etc. may be used for the production of pellets. Is particularly preferred. Next, the pellets are put into an injection molding machine to produce a molded body (Step S106).

In the process diagram shown in FIG. 1, waste plastic is melt-kneaded by an extruder to obtain a pellet-shaped plastic raw material. However, the form of the plastic raw material is not limited to this. For example, it may be in any form such as a sheet, a film, a pipe, and the like, and may be appropriately determined based on the type of the molding machine.

Here, in order to further simplify the recycling process, it is of course possible to add a pulverized and granulated plastic to a molding machine without producing pellets to produce a molded body. . In addition, conventionally known additives such as a heat stabilizer, a light stabilizer, an antistatic agent, a lubricant, a filler, a copper damage inhibitor, an antibacterial agent, and a coloring agent are added as necessary within a range that does not impair the effects of the present invention. May be. The step of adding these additives is preferably at the time of charging the raw materials to an extruder or an injection molding machine.

Hereinafter, a washing machine will be described as an example. The housing made of the same polypropylene resin (propylene-ethylene block copolymer), the water tank, and the dehydrator were removed from the discarded washing machine, washed with running water, and then washed with running water to obtain an average particle size of 0.
The mixture was pulverized to about 5 to 3 cm, and melt-kneaded at 230 ° C. using a twin-screw kneading extruder having a screw diameter of 25 mm to obtain pellet-shaped plastic raw materials. PP-1 (casing), PP-2 (water tank), P
P-3 (dehydrator).

Next, these plastic raw materials were put into a hopper of a 10-ton injection molding machine, and test specimens for measuring physical properties compliant with ASTM were prepared under injection conditions of a molding temperature of 230 ° C. and a mold temperature of 40 ° C. The physical properties of the test piece were measured.
Table 1 shows the measurement results. The tensile strength and tensile modulus are JIS K7113, the bending strength and flexural modulus are JIS K7203, and the Izod impact strength is JIS K7.
It measured according to 110.

[0022]

[Table 1]

As can be seen from Table 1, the physical properties of tensile strength, bending strength, flexural modulus, and Izod impact strength differ greatly depending on the plastic part of the raw material. Therefore, in the conventional recycling method, all the plastic parts having the same composition were mixed and molded. As a result, the quality of the obtained recycled product was reduced uniformly. Since the same parts that have the same degree of deterioration due to use are separated and collected and reused, high-quality, medium-grade, and low-quality recycled products can be obtained. The recycled product can be used in a wider range than in the case of.

For confirmation, the washing machines of the respective manufacturers were collected, the water tub was taken out, and the composition of the plastic used was investigated. As a result, the washing machines of the respective manufacturers had the same resin composition. Therefore, the water tubs were separately collected from the discarded washing machines of the respective companies, and a pellet-shaped plastic raw material was produced in the same manner as described above, and this was molded to produce a test piece. Then, the physical properties of the test pieces of each company were measured. Table 2 shows the measurement results. In addition, plastic raw materials from various manufacturers were mixed and molded to prepare test pieces, and the physical properties of the test pieces were measured. Table 3 shows the measurement results.

[0025]

[Table 2]

[0026]

[Table 3]

As is clear from Table 2, there is no superiority in the physical properties among the test specimens of the respective companies, and according to Table 3, the physical properties of the test specimens formed by mixing the plastic raw materials of the respective manufacturers are as follows.
It was almost the same as that of the test piece molded from a single plastic raw material. Therefore, it was found that the same parts can be separated and collected and reused regardless of the manufacturer.

Further, plastic materials to be reused may be appropriately mixed and used according to the required physical properties.
Of course, virgin materials may be mixed. The present inventors set the above-mentioned PP-1 which is considered to be deteriorated by irradiation with sunlight or the like and the above-mentioned PP-2 which is considered to have a small degree of deterioration in internal parts in an equal weight ratio. The mixed raw material PP-4 was prepared by mixing, and a test piece was prepared in the same manner as described above. The prepared test pieces (PP-1, PP-2, PP-4)
Was placed in an oven at 140 ° C., and a thermal oxidation deterioration test was performed as an accelerated life test. The results are shown in FIG. FIG.
The vertical axis indicates the tensile strength, and the horizontal axis indicates the time, showing the temporal change of the tensile strength. As is clear from this figure, PP
-2 (water tank) did not deteriorate until 1,800 hours, whereas PP-1 (housing) deteriorated in about 650 hours.
On the other hand, PP-4, which is a mixture of the two, had a longer life than PP-1, and did not deteriorate to about 800 hours. Therefore, it can be seen that by adjusting the mixing ratio of PP-1 and PP-2, a recycled product having a desired life can be obtained.

In order to obtain a higher quality recycled product, it is desirable to further separate the plastic component depending on the presence or absence of surface decoration and / or the color tone of the plastic component. Acrylic resin painted (ABS-1) and unpainted (ABS-) on the front cabinet (made of acrylic nitrile-butadiene-styrene resin) of the TV
2) was separated and collected, a test piece was prepared in the same manner as described above, and the physical properties were measured. Table 4 shows the results.

[0030]

[Table 4]

As is clear from Table 4, although the tensile strength, the bending strength, and the flexural modulus are not superior in both cases,
Tensile elongation and Izod impact strength are AB with surface coating
S-1 is a remarkably low value. Therefore, the quality of reclaimed products formed from a mixture of these materials will be low due to the effect of surface decoration, but if waste components are further separated based on the presence or absence of surface decoration, higher quality reclaimed products will be obtained. Can be

Further, regarding a color tone of a plastic part, when a dark colored part is melt-kneaded, the color tone generally approaches black. For this reason, the use of recycled products is limited to parts that cannot be seen from the outside. On the other hand, if light-colored components are mixed, they can be colored with a coloring agent even if a uniform color is not obtained, and can be used as exterior components. Therefore, if the plastic parts are further classified according to the color tone, the recycled products can be developed into various colors, and the usable range is expanded.

The plastic molded part that can be produced from the discarded plastic part is not particularly limited, and includes all plastic parts including those that have been produced only from virgin materials.

[0034]

According to the method of reusing plastic parts of the present invention, the same parts made of plastic having the same composition are separated and collected, melted, molded and reused, so that a high-quality recycled product can be obtained. In addition, recycled plastic can be used in a wide range of applications, and waste plastic can be reused at a high rate.

Here, if the plastic part is a thermoplastic resin, it can be easily reused.

Further, if the plastic parts are further classified according to the presence or absence of surface decoration and / or the color tone of the plastic parts, the quality of the recycled product can be further improved.

When the discarded product is a washing machine, it is easy to separate and collect plastic parts.

In the plastic raw material of the present invention, the same parts made of plastic having the same composition, which are separated and recovered from discarded products, are produced by pulverizing, melting and molding, so that recycled products of high quality and versatility are used. Is obtained.

Further, in the plastic molded part of the present invention, since the same part made of plastic having the same composition, which is separated and recovered from the discarded product, is produced by pulverizing, melting and molding, it has high quality and wide application.

[Brief description of the drawings]

FIG. 1 is a process chart showing an example of a recycling method of the present invention.

FIG. 2 is a diagram showing a change over time in tensile strength of each part by a thermal oxidation deterioration test.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Tetsuya Kadoma 22-22 Nagaikecho, Abeno-ku, Osaka-shi, Osaka Inside Sharp Corporation (72) Inventor Yoko Fukushima 22-22 Nagaikecho, Abeno-ku, Osaka-shi, Osaka (72) Inventor Motohide Nishio 22-22 Nagaikecho, Abeno-ku, Osaka City, Osaka F-term (reference) 4F301 AA11 AA21 BA21 BF03 BF08 BF12 BF15 BF27 BF31

Claims (7)

[Claims] 1. A plastic part characterized in that the same part made of plastic of the same composition is separated and collected from the discarded product, and the separated and collected plastic part is crushed, melted, molded and reused. Reuse method. 2. The method according to claim 1, wherein the plastic component is a thermoplastic resin. 3. The recycling method according to claim 1, wherein the plastic component is further classified based on whether or not surface decoration is applied. 4. The recycling method according to claim 1, wherein the plastic part is further classified according to a color tone of the plastic part. 5. The recycling method according to claim 1, wherein said discarded product is a washing machine. 6. The same part made of plastic of the same composition, which is separated and recovered from the discarded product, is crushed and melted.
A plastic raw material characterized by being molded and produced. 7. The same part made of plastic having the same composition, which is separated and recovered from the discarded product, is pulverized and melted.
Plastic molded parts characterized by being molded.