JPH07124950A - Molding comprised of thermosetting waste plastic and waste polystyrene and its manufacture - Google Patents

Abstract

PURPOSE:To make use of thermosetting plastic being a major part of a waste plastic which is used conventionally only in a limited use as a concrete shuttering for a concrete shuttering work. CONSTITUTION:Thermosetting waste plastic powder is radiation treated, then the obtained thermosetting waste plastic powder is heat-treated by styrene or a polymerizable styrene derivative, then an obtained product is pulverized, a pulverized matter obtained in this manner is mixed with waste polystyrene, heated and molded.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for effectively utilizing waste plastic and using it as a frame material for manufacturing a formwork used for concrete formwork construction. The present invention is particularly characterized in that a thermosetting waste plastic powder or pulverized product whose surface is at least treated with styrene or a polymerizable styrene derivative is mixed with waste polystyrene and is heat-molded. The present invention relates to a molded product composed of curable waste plastic and waste polystyrene. In particular, the present invention relates to a molded product composed of waste thermosetting plastic having a thermosetting waste plastic content of 20% or more, and waste polystyrene, and further manufacturing a formwork used for concrete formwork construction. To their utilization technology as frame material for

According to the present invention, the thermosetting waste plastic powder is further subjected to radiation treatment, the thermosetting waste plastic powder obtained is then heat treated with styrene or a polymerizable styrene derivative, and the resulting product is then produced. The present invention relates to a method for producing a molded product comprising thermosetting waste plastic and waste polystyrene, which comprises crushing the product, mixing the crushed product thus obtained with waste polystyrene, and heat-molding. More specifically, the present invention is to subject the thermosetting waste plastic powder to radiation treatment in air, and then subject the resulting thermosetting waste plastic powder to styrene or a polymerizable styrene derivative in an oxygen-free atmosphere. Heat treatment, for example to 80 ° C. or higher, then the product obtained is ground, the ground product thus obtained is mixed with waste polystyrene powder or ground product,
The present invention relates to a method for producing a molded article composed of waste thermosetting plastic and waste polystyrene, which is characterized by being heat-molded.

[0003]

2. Description of the Related Art In recent years, concrete formwork has been widely used in construction work. However, in order to manufacture a formwork used for the concrete formwork, As the frame material, raw trees of tropical forests such as Lauan are often used as raw materials. In fact, about 60% of the formwork material used for concrete formwork is plywood manufactured from Lauan. This plywood is made by laminating thin wood logs and adhering them together.
The fibers of wood are continuous, and they have the characteristics of being strong against bending and pulling forces when used as a formwork, being harder and having less bending deformation. However, it is hard to say that it still has sufficient strength and elastic modulus.
It is required to develop those having better properties. In addition, using raw wood obtained from tropical forests such as Lauan preserves the global environment and reduces the use of it even if it is unavoidable or unavoidable in order to prevent further deterioration of the environment. Is strongly demanded. From this point of view, the development of alternative formwork using new materials replacing wooden formwork has been strongly promoted.

The following are examples of such alternative molds. 1. 1. Particleboard reinforced with mesh-like fibers by using the residual materials from the sawmill and the demolition materials of the house as wood pieces. Utilizing a large amount of plant fiber contained in low-grade waste paper,
2. The waste paper is dried and defibrated, chemically treated, admixed with additives, and the resulting material is heat-compressed and molded to produce a board, and Polypropylene board reinforced with fiber made of virgin material. Some of these alternative forms have been used,
The mainstream of these alternative formwork is to recycle waste wood and used paper as materials. In recent years, of the amount of waste that is discharged, the amount of waste that is discharged is increasing significantly, and the amount is about 500 per year.
The amount is up to 10,000 tons, and the amount tends to increase more and more. Of the waste plastic, the amount of waste plastic discharged as industrial waste is about 2 million tons, and the amount of waste plastic discharged from homes amounts to about 3 million tons.

Of these waste plastics, thermoplastic waste plastics can be melted and returned to their original state when heat is applied, so that they can be remolded by heating. Utilizing this property, about 27% of industrial waste is recycled. It is used as a raw material and is reprocessed into the original product, or is used as a building civil engineering material such as piles, rods, and boards, and a material cycle is performed. However, thermosetting plastics are such that the molecules have a three-dimensional network structure, and once a raw material is molded into a product, it does not deform even if heat is applied again, and therefore it is discarded. The only way to recycle what has been recovered as plastic is to use the waste in finely crushed form, mixed and used as a filler for the same type of plastic. Although it can be used only for limited applications like this, its mixing ratio is about 20.
It has a problem that it can be blended only up to about%.
For this reason, most of the waste plastics consisting of thermosetting plastics must be landfilled at the waste disposal site or incinerated at present.
It is an urgent and important issue to promote the development of such thermosetting waste plastics in order to protect the global environment and effectively use resources.

Typical examples of thermosetting plastics are phenolic resins and urea resins. However, as shown in Table 1 below, they have a higher mechanical strength than thermoplastics, so if they are recycled materials. If it could be reused for alternative formwork, its utility value would be very high. Of the thermoplastics, polystyrene has a relatively high mechanical strength, and if it can be reused as a recycled material in the production of alternative molds, its utility value is considered to be very high.

[0007]

[Table 1]

However, until now, no alternative form made of recycled waste plastic has been provided. The present inventors have examined the use of waste polystyrene among thermosetting waste plastics and thermoplastics, and utilize the crushed thermosetting waste plastics as a filler for the waste polystyrene to obtain the recycled material thus obtained. If it could be used to manufacture alternative formwork, it would be possible to manufacture formwork used for concrete formwork construction with excellent properties, and I think that it would be possible to expand the use of thermosetting waste plastic. Diligently developed. However, if the thermosetting waste plastic powder is mixed as it is with the waste polystyrene pellets of the thermoplastic and the content of the thermosetting waste plastic powder is 20% or more, the thermosetting waste plastic powder A mixture consisting of plastic waste plastic powder and waste polystyrene pellets cannot be made into a uniform mixture and cannot be heat-molded. In fact, injection molding and extrusion molding were not possible, and it was not possible to manufacture a mold having excellent properties that could be used for mold construction. Further, generally, when different types of plastics are mixed to produce a product, there is a problem in that the mechanical strength of the product is reduced and the shape is irregular.

[0009]

The present inventors have completed the present invention as a result of earnest research and development for solving the above-mentioned obstacles or problems by a simple method. That is,
The present invention is characterized in that a thermosetting waste plastic powder or pulverized product having at least the surface thereof modified with styrene or a polymerizable styrene derivative is mixed with waste polystyrene and then heat-molded. The present invention relates to a molded product composed of waste thermosetting plastic and waste polystyrene. In particular, the present invention relates to a molded product composed of a thermosetting waste plastic having a thermosetting waste plastic content of 20% or more and a waste polystyrene. The present invention further irradiates the thermosetting waste plastic powder with radiation, then heat-treats the obtained thermosetting waste plastic powder with styrene or a polymerizable styrene derivative, and then pulverizes the obtained product. Then, the pulverized product thus obtained is mixed with waste polystyrene, and a molded product comprising thermosetting waste plastic and waste polystyrene characterized by being heat-molded is provided. More specifically, the present invention is to subject the thermosetting waste plastic powder to radiation treatment in air, and then subject the resulting thermosetting waste plastic powder to styrene or a polymerizable styrene derivative in an oxygen-free atmosphere. Characterized in that it is heat-treated, for example, heat-treated at 80 ° C. or higher, and then the obtained product is crushed Also provided is a molded article composed of waste thermosetting plastic and waste polystyrene.

The present invention is characterized in that a thermosetting waste plastic powder or pulverized product having at least the surface thereof modified with styrene or a polymerizable styrene derivative is mixed with waste polystyrene and then heat-molded. The present invention relates to a method for producing a molded product composed of waste thermosetting plastic and waste polystyrene. Particularly, in the present invention, when the thermosetting waste plastic content is 20% or more, for example, 50
% Or more, it also relates to a method for producing a molded article composed of waste thermosetting plastic and waste polystyrene. The present invention further irradiates the thermosetting waste plastic powder with radiation, then heat-treats the obtained thermosetting waste plastic powder with styrene or a polymerizable styrene derivative, and then pulverizes the obtained product. Then, the pulverized product thus obtained is mixed with waste polystyrene and the mixture is heat-molded to provide a method for producing a molded product comprising thermosetting waste plastic and waste polystyrene. More specifically, the present invention is to subject the thermosetting waste plastic powder to radiation treatment in air, and then subject the resulting thermosetting waste plastic powder to styrene or a polymerizable styrene derivative in an oxygen-free atmosphere. Thermosetting, characterized in that it is heat treated, for example to 80 ° C. or higher, the product obtained is then crushed, and the crushed product thus obtained is mixed with waste polystyrene powder or crushed product and heat molded. The present invention relates to a method for producing a molded article made of waste plastic and polystyrene.

Examples of the thermosetting waste plastic include crushed products of epoxy resin, silicone resin, unsaturated polyester resin, phenol resin, urea resin and the like, and those having relatively high mechanical strength are preferred. Use. These thermosetting waste plastics may be composed of a miscellaneous mixture classified as thermosetting plastics among industrial wastes or waste plastics collected as waste from households. It may include waste plastics other than those classified, and most of the constituents of which are thermosetting plastics. Preferable examples of the thermosetting waste plastic that can be used here include crushed molded products such as phenol resin and urea resin. The phenol resin refers to a resin obtained by a condensation reaction of phenols and aldehydes, and as the phenols, for example, phenol,
Examples include meta-paracresol, xylenol, bisphenol A, bisphenol F, meta-tertiary butylphenol, resorcin, and the like. Examples of aldehydes include formaldehyde, paraformaldehyde, acetaldehyde, propionaldehyde, and the like. Ingredients may be included. The urea resin refers to one obtained by a condensation reaction of ureas and aldehydes, and the ureas include unsubstituted urea, mono- or dialkyl-substituted ureas, mono- or diaryl-substituted ureas, and the like. Examples thereof include formaldehyde, paraformaldehyde, acetaldehyde, propionaldehyde, and the like, but constituent components other than these may be contained. As the thermosetting waste plastic, a crushed product of a phenol resin or a crushed product of a urea resin may be used singly or may be used by mixing them at an appropriate ratio. . The thermosetting waste plastics used here include those derived from phenol resin molded products or those derived from urea resin molded products in as uniform a form as possible. preferable.

In the present invention, the pulverized product obtained by pulverizing the thermosetting waste plastic powder or the molded product is subjected to radiation treatment in air. This radiation irradiation process can be performed by using cobalt 60, an electron beam irradiation device, high-level radioactive waste, or the like.
Further, those irradiation sources can perform irradiation of, for example, about 3 kGy or more, and further irradiation of about 5 kGy or more, for example, irradiation of 10 to 100 kGy. These radiation irradiation sources can be appropriately selected according to the type and composition of the thermosetting waste plastic, and the irradiation amount can be appropriately selected. When the thermosetting waste plastic is irradiated with radiation, radicals are generated in the plastic molecules, and then oxygen in the air reacts with the generated radicals to form peroxide. Therefore, as long as this irradiation treatment is carried out so that a peroxide that can be sufficiently used in the next treatment is formed, an appropriate radiation irradiation source,
The irradiation amount can be selected.

The radiation-treated thermosetting waste plastic is then treated with styrene or a polymerizable styrene derivative. The term "polymerizable" as used herein means to have a group capable of reacting with radicals generated by thermal decomposition such as a peroxide molecule, and having a group capable of being easily polymerized by heat or the like.
Therefore, the polymerizable monomer having the same function is not limited to styrene or a polymerizable styrene derivative, and can be used without departing from the object of the present invention. Examples of styrene and polymerizable styrene derivatives include styrene monomers, alkyl-substituted styrenes, halogen-substituted styrenes, and the like, and styrene monomers are preferably used. When styrene monomer is used as the treating agent, the thermosetting waste plastic is immersed in the styrene monomer and heat-treated. This heating causes the peroxides in the treated thermosetting waste plastic to decompose and generate radicals, which then react with the polymerizable styrene moieties to cause graft polymerization and at the same time the polymerizable styrene moieties. Any substance capable of causing the thermal polymerization of (1) to form a mixed solid material composed of thermosetting waste plastic and polystyrene. It is preferably carried out by heating to a temperature of 80 ° C. or higher. The heating temperature can be appropriately selected without departing from the object of the present invention. In treating the thermosetting waste plastic that has been subjected to radiation irradiation, it is desirable that the treating agent such as styrene monomer removes oxygen dissolved therein in advance.

The solid mixture of thermosetting waste plastic and polystyrene is pulverized by a usual method to obtain a powder or a pulverized product. The mixed solid material composed of the pulverized thermosetting waste plastic and polystyrene is mixed with the waste polystyrene. Mixing can be done well. The mixing of the solid mixture of the pulverized thermosetting waste plastic and polystyrene and the waste polystyrene can be uniformly mixed with the waste polystyrene even if the content of the thermosetting waste plastic is 50% or more. It is possible and does not cause a substantial problem in the distribution of both components in the molded product of the recycled product in the subsequent heat molding treatment. When this mixture of solid waste consisting of pulverized thermosetting waste plastic and polystyrene and waste polystyrene is heat-treated, the pulverized thermosetting waste plastic functions as a filler, and the polystyrene part acts as an adhesive. However, the thermosetting waste plastics can also be bonded together and molded. In the mixture of the thermosetting waste plastic and the waste polystyrene, styrene is radiation-grafted on or around the thermosetting waste plastic molecule as shown in FIG. 1 and also around the thermosetting waste plastic powder. It is believed that they are chemically bound by polymerization, whereby the thermosetting waste plastic and the waste polystyrene become compatible and form a thermoformable mixture. Therefore, it will be appreciated that the starting raw materials used are not limited as long as such a mechanism is utilized.

Examples of the waste polystyrene include those obtained by crushing polystyrene molded products such as multipurpose polystyrene and impact polystyrene, and those having relatively large mechanical strength are preferably used. These waste polystyrenes may contain a styrene resin composed of acrylonitrile / styrene, a styrene resin composed of acrylonitrile / butadiene / styrene, or the like. These polystyrenes may consist of miscellaneous mixtures classified as thermoplastic waste plastics among waste plastics recovered as industrial waste or household waste, and most of the constituents are polystyrene. You may include things. Preferable examples of the waste polystyrene that can be used here include crushed polystyrene molded products such as waste polystyrene pellets. As the waste polystyrene, a product obtained by crushing a molded product of multipurpose polystyrene or a product obtained by crushing a molded product of impact polystyrene may be used alone, or may be used by mixing them at an appropriate ratio. As the waste polystyrene used here, those obtained by containing polystyrene in a uniform form as much as possible from those derived from resin molded products are used.
It is more preferable that they give the final product having constant properties.

As for the mixing ratio of the thermosetting waste plastic and the waste polystyrene, it is desirable to use a large amount of the thermosetting waste plastic whose use has been limited so far. The amount can be 20% or more by weight. According to the present invention, as long as the mechanical properties of the obtained heat-molded product are not deteriorated or the heat-molding process is not adversely affected, the mixing amount of the thermosetting waste plastic can be increased, and the thermosetting waste plastic can be used as a whole. The amount of waste plastic can be blended in 50% or more by weight. Even if the amount of the thermosetting waste plastic is 50% or more by weight with respect to the whole, there is no problem in the heat molding process, and a molded product having excellent properties can be obtained. As the heat molding method, a usual plastic molding method can be applied, and for example, a compression molding method, an injection molding method, an extrusion molding method or the like can be used. In the compression molding method, a multi-stage press is used, and continuous molding such as using a rotary table, impact compression molding, ultrasonic compression molding, hydraulic molding, etc. are appropriately selected and processed according to the purpose. . Among injection molding methods, there are those that use a plunger type injection molding machine such as an in-line screw type.
A method using a program-controlled injection molding machine can be mentioned. Further, in injection molding, it is also possible to perform heat molding as a composite material such as FRP. Foam molding can also be performed when heat molding is applied.

According to the present invention, the mixture of the pulverized material obtained from the mixed solid material of thermosetting waste plastic and polystyrene and the waste polystyrene is heat-molded and used for the concrete formwork. The frame can be manufactured. The formwork thus obtained may be a simple flat plastic plate, may be a flat plate obtained by laminating simple flat plates in multiple layers, or may be a flat plate having a corrugated cardboard-like cross-sectional structure composed of plastic plates. It may be a ribbed plastic plate having a flat plate. According to the present invention, a plate suitable for a formwork used for concrete formwork construction is prepared by using a mixture of a pulverized product obtained from a solid mixture of thermosetting waste plastic and polystyrene and waste polystyrene. It can be manufactured easily and inexpensively and on an industrial scale. It is also possible to add a foaming agent at the time of heat-molding the plastic plate and heat-foam it after molding to obtain a lightweight plastic plate.

Various types of foaming agents are known, and decomposition type foaming agents and volatile type foaming agents are known.
As the decomposition-type foaming agent, decomposition temperature, amount of generated gas, diffusibility into the base material, selected from among preferable conditions such as corrosiveness of decomposition gas, sodium bicarbonate, ammonium carbonate, ammonium bicarbonate, Ammonium nitrite,
Azide compounds, sodium borohydride, light metals (magnesium, zinc, aluminum, etc.), azodicarbonamide, azobisformamide, azobisisobutylnitrile, diazoaminobenzene, N, N'-dinitron pentamethylenetetramine, N, N '. -Dimethyl N, N '
-Dinitron terephthalamide, benzene sulfonyl hydrazide, paratoluene sulfonyl hydrazide, oxybis benzene sulfonyl hydrazide, etc. are mentioned.
As the volatile foaming agent, pentane, neopentane, hexane, isohexane, heptane, isoheptane, benzene, toluene, dichloromethylene, trichloroethylene, dichloroethane, dichlorotetrafluoroethane,
Examples thereof include trichlorofluoromethane. These foaming agents can be appropriately selected and used from commercially available products or known general-purpose products depending on the intended use of the final product.

[0019]

EXAMPLES Next, the present invention will be specifically described by way of examples. Example 1: A molded product of phenol resin and urea resin collected as industrial waste was crushed and used as a thermosetting waste plastic. Phenol resin powder, urea resin powder, and a mixture of phenol resin powder and urea resin powder as thermosetting waste plastics were irradiated with radiation by an electron beam irradiation device so that the irradiation dose was 10 kGy in air. Next, the radiation-treated phenol resin powder, urea resin powder, and a mixture of the phenol resin powder and urea resin powder were each immersed in a styrene monomer solution that had been sufficiently treated to remove dissolved oxygen. , Urea resin powder and a mixture of phenol resin powder and urea resin powder,
Place in a furnace and heat to about 110 ° C. for about 30 minutes.
The obtained solid matter was crushed by a crusher into pieces having a size of about 1 mm or less, and polystyrene molded articles collected as industrial waste were crushed and mixed with waste polystyrene obtained. It was observed that the mixture was a uniform mixture of small pieces derived from thermosetting waste plastic and waste polystyrene pellets.

Example 2: The thermosetting waste plastic-derived small pieces obtained in Example 1 and waste polystyrene pellets were uniformly mixed, and the mixture was heated up to about 200 ° C. with a small manual injection molding machine. Heat treatment for about 3 minutes, thickness 4mm
Injection molded into a plastic plate. From this plastic plate, a plastic plate test body having a length of 80 mm, a width of 10 mm and a thickness of 4 mm was prepared. Bending tests were conducted on the plastic plates when phenol resin powder, urea resin powder and a mixture of phenol resin powder and urea resin powder were used as the thermosetting waste plastics, and the results are shown in Table 2. For comparison, plywood was prepared according to Japanese agricultural standards. The size of the plywood test piece is 80 mm long x 10 width
mm × thickness 4 mm was cut out and made the same size as the test piece of the plastic plate. A bending test was conducted in the same manner, and the results are shown in Table 2.

[0021]

[Table 2]

Bending strength is a very important physical property for the function of the formwork used for concrete formwork construction. As a result of the above, not only is the mechanical strength of the molded product of thermosetting waste plastic and waste polystyrene according to the present invention superior to that of thermoplastics, but it is also comparable to that of plywood. It was shown to be a level. In this way, it was confirmed that the plastic plate, which is a molded product of thermosetting waste plastic and waste polystyrene, can be replaced with plywood. Further, different kinds of thermosetting waste plastics can be treated and molded according to the present invention, and the resulting product does not have a decrease in mechanical strength, and its shape is not uneven, and plywood can be formed. The advantage is that you can get a comparable board.

Example 3: A mixture of the small pieces derived from the thermosetting waste plastic obtained in Example 1 and the waste polystyrene pellets was uniformly heated to about 300 ° C. for about 10 minutes and extruded. By processing, a simple flat plastic plate having a thickness of 15 mm was prepared. Similarly, a piece obtained by uniformly mixing the small pieces derived from the thermosetting waste plastic obtained in Example 1 and the waste polystyrene pellets is treated at about 300 ° C.
Was heat-treated for about 10 minutes, and then extrusion-molded to prepare a flat plate having a corrugated cardboard-shaped cross-sectional structure composed of a plastic plate having a thickness of 4 mm. In addition, the thermosetting waste plastic-derived small pieces obtained in Example 1 and the waste polystyrene pellets were uniformly mixed at about 300 ° C.
Heat treatment for about 10 minutes, then press molding,
A plastic plate with ribs having a flat plate with a thickness of 10 mm was prepared. The shape of the plastic plate thus obtained is shown in FIG.

[0024]

EFFECTS OF THE INVENTION Thermosetting plastics, which can be used only for a limited number of purposes and which occupy most of what is discharged as waste plastic waste, can be heated and remolded, and by utilizing this property, it can be used as a recycled raw material or construction civil engineering. It is used as a formwork used for concrete formwork construction, and a material cycle is performed. Since it has greater mechanical strength than thermoplastics such as phenolic resin or urea resin, it can be used to manufacture formwork used for concrete formwork with excellent properties, and use of thermosetting waste plastic Can be expanded. By opening the way to use the thermosetting waste plastic by injection molding or extrusion molding, it is possible to manufacture a mold having excellent properties that can be used for mold construction. In addition, it becomes possible to mix different types of plastics to produce a product, and there is no problem that the mechanical strength of the product is lowered or the shape is irregular.

[Brief description of drawings]

1 schematically shows the micromolecular structure of a mixture of thermosetting waste plastic and waste polystyrene according to the invention.

FIG. 2 shows a typical example of the shape of a plastic plate which is a molded product of thermosetting waste plastic and waste polystyrene according to the present invention. (A) A simple flat plate, (b) a flat plate having a corrugated cardboard-shaped cross-sectional structure, and (c) a ribbed plastic plate.

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Claims (11)

[Claims] 1. A thermosetting waste plastic powder or pulverized product whose surface is at least modified with styrene or a polymerizable styrene derivative is mixed with waste polystyrene, and the mixture is heat-molded. A molded product composed of waste thermosetting plastic and waste polystyrene. 2. The molded product according to claim 1, wherein the molded product comprises a thermosetting waste plastic having a thermosetting waste plastic content of 20% or more and waste polystyrene. 3. The molded product according to claim 1, wherein the molded product comprises thermosetting waste plastic having a thermosetting waste plastic content of 50% or more and waste polystyrene. 4. The molded product according to claim 1, wherein the molded product is a concrete formwork construction formwork. 5. A thermosetting waste plastic powder is irradiated with radiation, and the resulting thermosetting waste plastic powder is then heat treated with styrene or a polymerizable styrene derivative,
The molded product according to claim 1, which is obtained by crushing the obtained product, mixing the crushed product thus obtained with waste polystyrene, and heat-molding the mixture. 6. A thermosetting waste plastic powder is irradiated with radiation in air, and the resulting thermosetting waste plastic powder is heated to 80 ° C. or higher with styrene or a polymerizable styrene derivative in an oxygen-free atmosphere. 2. Molding according to claim 1, characterized in that the product is treated, then the product obtained is ground, and the ground product thus obtained is mixed with waste polystyrene powder or ground product and thermoformed. object. 7. Thermosetting waste plastic powder or pulverized product having at least its surface modified with styrene or a polymerizable styrene derivative is mixed with waste polystyrene and heat-molded. A method for producing a molded product composed of waste plastic and waste polystyrene. 8. The molded product according to claim 7, wherein the molded product is composed of the thermosetting waste plastic and the waste polystyrene when the content of the thermosetting waste plastic is 20% or more. A method for producing the described molded article. 9. A molded product produced from a thermosetting waste plastic and a waste polystyrene when the content of the thermosetting waste plastic is 50% or more. The method for producing a molded article according to item. 10. A thermosetting waste plastic powder is subjected to radiation treatment, then the obtained thermosetting waste plastic powder is heat treated with styrene or a polymerizable styrene derivative, and then the obtained product is ground. The method for producing a molded article according to claim 7, wherein the pulverized product thus obtained is mixed with waste polystyrene and the mixture is heat-molded. 11. A thermosetting waste plastic powder is irradiated with radiation in air, and the resulting thermosetting waste plastic powder is then treated with styrene or a polymerizable styrene derivative in an oxygen-free atmosphere. Heat treatment to 80 ℃ or higher,
8. The method for producing a molded product according to claim 7, wherein the obtained product is then crushed, and the crushed product thus obtained is mixed with a waste polystyrene powder or a crushed product and heat-molded.