JP2002256100A - Disposing device of waste plastic containing flame- retardant - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a disposing device to efficiently separate a flame-retardant component and a resin component for the disposal and reuse of a waste plastic containing a flame-retardant. SOLUTION: This disposing device comprises a wet means to allow at least a part of the flame-retardant contained in the waste plastic to be dissolved therein and a kneading means.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a processing apparatus for separating a flame retardant and a resin component from waste plastic containing a flame retardant, which is used for a housing of a monitor such as a television or a computer. It is.

[0002]

2. Description of the Related Art At present, styrene resin and ABS are used as housings for televisions, computer monitors and videos.
Thermoplastic resins such as (acrylonitrile-butadiene-styrene) resin and high impact polystyrene resin (such as a blend of polybutadiene and polystyrene) having improved impact resistance are generally used. However, there is a problem that the thermoplastic resin alone has high flammability. Therefore, from the viewpoint of preventing the spread of fire during a fire, a resin composition in which a flame retardant such as a flame retardant or a flame retardant aid is blended with a resin to make the resin flame retardant is widely used. Halogenated flame retardants have a high flame retardant effect on various plastic resins and are inexpensive, so they are used on a world level.

[0003]

Halogen-based flame retardants, particularly bromine-based flame retardants, have an excellent flame-retardant effect on aromatic resins represented by styrene-based resins. It has been used in large quantities in body and component materials. Therefore, a large amount of the resin composition containing a brominated flame retardant is disposed of together with the disposal of these home electric appliances.

[0004] In general, the method of treating resin waste is mainly incineration and landfill, and only a part is reused by heating and melting. Considering the tightness of landfill sites, it is desirable to incinerate waste plastics. However, resin compositions containing flame retardants are difficult to incinerate because of their high degree of flame retardancy. Is getting harder.

[0005] In addition, awareness of environmental problems has increased, and the harmfulness of halogenated organic substances to the environment has been pointed out, and the use of halogenated organic substances is being regulated. Currently, manufacturers are considering switching from halogen-based flame retardants to flame-retardants that do not contain halogenated organic substances, such as phosphorus-based compounds.However, phosphorus-based compounds are more flame-retardant than halogenated organic substances. Conversion from halogenated organic matter is weak
It is difficult to progress.

Furthermore, in recent years, there has been a strong demand for recycling petrochemical-derived resources, and the establishment of methods for treating and recycling resin waste has become an important issue. Various studies have been made on a method of treating a resin composition containing a flame retardant. However, acid treatment (Japanese Unexamined Patent Publication No.
No. 57812) and high-temperature treatment (Japanese Unexamined Patent Publication No. 8-29975).
9, JP-A-9-262565, JP-A-2000-19
No. 8874), which mainly focuses on thermal recycling methods such as complete decomposition of the resin and the flame retardant, and there has been almost no effort aimed at material recycling of the resin. Also, JP-A-10-1952
No. 34 proposes a method of modifying and separating a resin out of resins containing a flame retardant. Although it is intended to use the resin for another purpose by functionalizing the resin, we judge that it is more urgent to establish a recycling law mainly for recycling for general purpose use.

[0007] The present invention has been proposed in view of such a situation, and in a waste plastic containing a flame retardant, a flame retardant component and a resin component can be efficiently, easily, quickly, and continuously. The aim is to provide a processable method.

[0008]

Means for Solving the Problems The present inventors have conducted intensive studies on the above-mentioned problems, and as a result, in a kneading process before re-molding waste plastics containing a flame retardant, before or after or during a specific process. The present inventors have found a method of separating the flame retardant component from the resin component by positively dissolving only the flame retardant component by contact with a solvent, and completed the present invention.

The first invention (corresponding to claim 1) is an apparatus for treating waste plastic containing a flame retardant having a kneading means after a wet means for dissolving at least a part of the flame retardant contained in the waste plastic. is there.

A second aspect of the present invention (corresponding to claim 2) is an apparatus for treating a waste plastic containing a flame retardant having means for kneading while dissolving at least a part of the flame retardant contained in the waste plastic.

The third invention (corresponding to claim 3) provides a waste plastic containing a flame retardant having a wet means comprising an organic solvent for dissolving at least a part of the flame retardant contained in the waste plastic after the kneading means. Processing device.

According to a fourth aspect of the present invention (corresponding to claim 4), the wet means comprising an organic solvent for dissolving at least a part of the flame retardant contained in the waste plastic is maintained at a temperature higher than the heat deformation temperature of the resin. A third aspect of the present invention is an apparatus for treating waste plastic containing the flame retardant of the present invention.

A fifth invention (corresponding to claim 5) provides a waste plastic containing the flame retardant of any of the first to fourth inventions, wherein the flame retardant is a bromine-based flame retardant. Processing device.

According to a sixth aspect of the present invention (corresponding to claim 6), the waste plastic is a polymer having a styrene structure, comprising the flame retardant of any one of the first to fourth aspects of the present invention. It is a processing device for waste plastic.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention relates to a method for continuously and easily removing a resin from which at least a part of a flame retardant has been removed by bringing a waste plastic containing a flame retardant into contact with a solvent and simultaneously or simultaneously kneading the resin. The invention relates to a device obtained in a method and in a short time.

The waste plastic described here refers to an unnecessary plastic material or plastic scrap generated in a process at a manufacturing site or the like, or a resin recovered after being used for a housing of a home electric appliance. It means both a plastic resin and a thermosetting resin. Further, these waste plastics contain at least a flame retardant for imparting flame retardancy, and in addition to the above, according to the use of the resin composition, a flame retardant auxiliary, a stabilizer, a colorant, a flow modifier. And a plastic formed by mixing a resin and various additives with an additive such as a release agent. Further, the surface may be coated with an acrylic coating.

Examples of the flame retardant include phenyl ether flame retardants such as decabromodiphenyl ether, octabromodiphenyl ether, and tetrabromodiphenyl ether; bisphenol A-type flame retardants such as tetrabromobisphenol A (TBA); and hexabromocyclododecane. , Bistribromophenoxyethane, tribromophenol, ethylenebistetrabromophthalimide, brominated flame retardants such as TBA polycarbonate oligomers, brominated polystyrene, and TBA epoxy oligomers; and chlorine based flame retardants such as chlorinated paraffin, perchlorocyclopentadecane, and chlorendic acid Flame retardants, phosphorus-based flame retardants, flame retardants containing nitrogen compounds, and inorganic flame retardants are known.

The flame retardant contained in the waste plastic composition may be a single type or a mixture of plural types, and the content thereof may be any. Although it depends on the required flame retardant grade, it is generally mixed in an amount of 10 to 20% by weight based on the weight of the resin.

On the other hand, plastics can be applied to any plastics, but are particularly effective for styrenic polymers. Examples of the styrene-based polymer include polymers composed of polystyrene, poly-α-methylstyrene, styrene-butadiene, styrene-acrylonitrile, styrene-butadiene-acrylonitrile, styrene-maleic anhydride, and high-impact high-impact polystyrene. .

The above-mentioned styrene-based polymers may be used alone or as a mixture of two or more. Further, a mixture with another polymer may be used. The molecular weight of the styrenic polymer is also arbitrary, but is preferably 3,000 to 1,000,000.
About 00 is preferable.

Among brominated flame retardants, a group of compounds called non-decatype generally show good solubility in general-purpose solvents, whereas decabromodiphenyl ether (commonly known as decabro) is used as a solvent. Insoluble. According to the present invention, regardless of the type and content of the flame retardant in the resin,
It is possible to separate the flame retardant component from the resin component by the same treatment method, which is also an important feature of the present invention.

The kneading means as used herein means a device capable of continuous kneading, such as an extruder, injection molding machine, blow molding machine or the like having a single or twin screw. Also includes those that have been improved accordingly.

The solvent used for dissolving the flame retardant of the present invention can be used repeatedly by performing a distillation operation, and the amount of use can be suppressed. Further, the flame retardant and other additives recovered as a residue after the removal of the solvent can be recovered without diffusing into the atmosphere. Further, these have a very small bulk as compared with the initial weight of the entire resin composition, and can be handled under special management.

As described above, according to the present invention, it is possible to carry out processing in a form that is environmentally friendly, such as proper processing, recovery and recycling of substances that may cause environmental pollution, and reduction in the amount of solvent used.

Hereinafter, the processing method of the present invention will be described in detail.

The apparatus for treating waste plastic containing a flame retardant in the present invention has a kneading means after a wet means for dissolving at least a part of the flame retardant contained in the waste plastic. As a wet method for dissolving at least a part of the flame retardant contained in the waste plastic, a method in which the waste plastic containing the flame retardant is poured into a solvent and agitated, an extraction method, and the like are considered. At this time, a heating treatment or the like may be performed to increase the solubility of the flame retardant. Thereafter, the waste plastic from which at least a part of the flame retardant has been removed is separated from the solution, and the separated plastic is placed in an extruder equipped with a hopper or the like and kneaded, whereby a recycled resin can be obtained.
Regarding this dissolving operation and the subsequent kneading operation, it is desirable that a desired recycled resin product can be obtained by one treatment.
There is no problem even if it is performed twice or more from the viewpoint of the removal rate of the flame retardant and the operability.

A more preferred apparatus for treating waste plastic containing the flame retardant of the present invention has means for kneading while dissolving at least a part of the flame retardant contained in the waste plastic. As described above, there are cases where the kneading work and the work to convert the flame retardant using a solvent are performed separately, but by performing them at the same time, it is possible to promote reduction of energy loss, shortening of work time, etc. Becomes The equipment can be handled by improving the hopper part and vent part, and while extracting and removing the flame retardant component with the solvent while coexisting with the solvent, kneading as waste plastic from which at least a part of the flame retardant component has been removed can do.

As a further preferred apparatus for treating waste plastic containing the flame retardant of the present invention, there is provided, after the kneading means, wet means comprising an organic solvent for dissolving at least a part of the flame retardant contained in the waste plastic. .
Usually, the resin after passing through the extruder once passes through a cooling water tank or the like before being cut, and there is a work of lowering the temperature, but in the present invention, apart from cooling with water, from the surface of the kneaded resin with an organic solvent, A means for removing the flame retardant is provided. In the case of the present apparatus, since the improvement of the apparatus is the easiest compared with the above two cases, the investment cost can be reduced. This may have a function of cooling means, or may have a structure provided with a separate cooling water tank.

In a further preferred aspect of the present invention, the wet means provided after the kneading means is maintained at a temperature not lower than the heat deformation temperature of the resin. By increasing the temperature of the organic solvent, particularly by maintaining the temperature at or above the heat deformation temperature of the resin, the flame retardant is more easily released from the kneaded resin.

When the solubility of decabro and various other brominated flame retardants themselves were separately examined, it was found that the solubility was 100 ° C. to 150 ° C.
By increasing the temperature of the solvent to about ° C, it was confirmed that any flame retardant could be completely dissolved at a concentration of about 5%. Increasing the solvent temperature not only makes the resin softer, but also improves the solubility of the flame retardant contained in the resin in the solvent, enabling the same treatment regardless of the type of flame retardant. Which is also an important feature of the present invention.

The conditions necessary for the solvent used in the processing apparatus of the present invention include: 1. The flame retardant is relatively easily dissolved or dispersed. This means that the resin component does not melt or hardly melts. As a result of studying various solvents, it was found that a glycol ether compound group was most suitable for this condition. In the case of a glycol ether-based dialkyl compound in which both terminal groups are methyl groups, the resin component is also easily dissolved. Therefore, when used as a treatment for a flame retardant having good solubility, the flame retardant and the resin are separated again. A process is required.

It is considered that these solvents are preferable because many of them have a relatively high flash point and are more safe as a working environment.

Specific examples of the glycol ether compound include ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol,
Diethylene glycol methyl ether, diethylene glycol ethyl ether, diethylene glycol propyl ether, diethylene glycol butyl ether, dipropylene glycol methyl ether, dipropylene glycol ethyl ether, dipropylene glycol propyl ether, dipropylene glycol butyl ether,
Triethylene glycol methyl ether, triethylene glycol ethyl ether, triethylene glycol propyl ether, triethylene glycol butyl ether, tripropylene glycol methyl ether, tripropylene glycol ethyl ether, tripropylene glycol propyl ether, tripropylene glycol butyl ether, and the like. .

Further, the higher the concentration of these glycol ether compounds, the more the solvent used in the treatment apparatus of the present invention can increase the insolubility in the styrene polymer and the solubility in the flame retardant. It is desirable to make the concentration of the glycol ether compound as high as possible. The concentration is preferably contained as a main component, and is preferably at least 50% by weight or more of the total weight of the composition.

As the solvent used in the treatment apparatus of the present invention, a powder or a solution of a known additive can be added as needed, to the extent that the dissolving ability of the solvent is not significantly impaired.
For example, antioxidants, antibacterial / antifungal agents, pest repellents, coloring agents, foaming agents, surfactants, powder fluidity improvers, and the like are appropriately used.

The recovered resin is molded again to form a TV.
It can be reused for products that use various thermoplastic resins, such as monitor housings. Note that components such as a colorant may be mixed as long as they do not significantly affect the recycled resin.

Hereinafter, the present invention will be specifically described. FIG. 1 shows a schematic view of the apparatus used in the present invention. This apparatus is formed by a wet means for dissolving at least a part of the flame retardant and a kneading means. The simplest structure comprises a container containing an organic solvent and an extruder. A container (A) 1 for wet-processing waste plastic containing a flame retardant has a resin inlet 2, a resin outlet 3, a solvent inlet (A) 4, and a solution recovery port (A) 5. In addition, a deaeration port, a stirrer, and the like may be provided. After the solvent is removed from the container 1, the resin after the wet processing is sequentially supplied to the hopper 7 of the extruder 6 through the resin outlet 3. The resin is conveyed while being melted and kneaded finely by shearing friction and heating caused by rotation of a single-screw or twin-screw 8, extruded through a die 9, cooled in a cooling water tank 10, cut by a cutting machine 11, and pelletized. And collected in the collection container 12. This time, a device having a vent at 13 was used, but this is not always necessary. It is also desirable to insert a screen mesh or the like depending on the degree of resin contamination. It is desirable that the extruder 6 can set at least two different temperature settings, preferably about four different temperature settings including the die section 9.

In the present invention, as shown in FIG. 2 and FIG. 3, there is a wet processing means for removing a flame retardant from waste plastics in a kneader, or a wet processing means disposed after a kneader. Can be used. In the drawing, the solvent put in the container (B) 14 for wet processing and the resin kneaded in the screw are designed to come into contact with each other, and the solvent is injected from the solvent injection port (B) 15. A pipe is provided so as to be recovered from the solution recovery port (B) 16. Container (C) 17 for wet processing
Is provided after the die 9 of the extruder 6, and extracts the high-temperature resin coming out of the die in a solvent.
At this time, it is desirable to increase the surface area in contact with the solvent by reducing the diameter of the dice or increasing the number of dice. It is also possible to increase the removal efficiency by heating the temperature of the container (C) 17 for wet processing by providing a separate cooling water tank or the like.

Needless to say, the treatment may be performed by combining a plurality of these kneading means and wet means.

[0040]

(Example 1) In this example, a resin composition (weight average molecular weight of resin: 35,000) composed of a flame retardant component: tetrabromobisphenol A and a resin component: polystyrene was prepared as waste plastic. The flame retardant component and the resin component contained in the resin composition were separated. At this time, the flame retardant was adjusted so as to be contained at 10 parts by weight with respect to the resin composition.

First, the resin composition was roughly crushed into a block of about 5 mm square, added to a wet processing vessel as shown in FIG. 1 together with dipropylene glycol methyl ether, and stirred at about 100 ° C. for 10 minutes. Thereafter, the solution was first recovered from the solution recovery port, and then the resin was moved from the resin removal port to the hopper and supplied to the extruder that had been operated with preheating. The supplied resin was melt-kneaded at a die temperature of 200 ° C. to obtain pellets.

The residual amount of the flame retardant of the obtained resin was measured by GPC.
%. Further, when the weight average molecular weight of the polystyrene before and after the treatment was examined, no significant difference was found in the change in the molecular weight, and it was found that the recovered polystyrene could be used again as a raw material. Further, it was found that 98% of the initial weight of the solvent used at the beginning can be reused by separately collecting and distilling the solvent.

Example 2 In this example, as waste plastic, a flame retardant component: decabromodiphenyl ether,
Resin component: A resin composition (weight average molecular weight of resin: 35,000) composed of polystyrene was prepared, and a flame retardant component and a resin component contained in the resin composition were separated. At this time, the flame retardant was adjusted so as to be contained at 10 parts by weight with respect to the resin composition.

First, the resin composition was roughly crushed into blocks of about 5 mm square, and a study was conducted using an apparatus in which wet processing and kneading processing were integrated as shown in FIG. First, the crushed waste plastic is arranged so as to be stably supplied to the hopper, the temperature of the container (B) for wet processing is set to 180 ° C., and dipropylene glycol is supplied from the solvent injection port (B). The solution containing at least a part of the flame retardant extracted into the solvent during the kneading and kneading was recovered from the solution recovery port (B). The temperature of the die at this time was set to 200 ° C., and pellets were obtained.

The residual amount of the flame retardant of the obtained resin was measured by GPC.
It was found that up to 2.5% could be removed. When the weight average molecular weight of the polystyrene before and after the treatment was examined,
No significant difference was found in the change in molecular weight, indicating that the recovered polystyrene could be used again as a raw material. In addition, it was found that 99% of the initial weight of the used solvent can be reused by separately collecting and distilling.

Example 3 In this example, as a waste plastic, a HIPS resin composition (weight average molecular weight of resin: 36,000) containing 10 parts by weight of a flame retardant mainly composed of decabromodiphenyl ether was used. The flame retardant component and the resin component contained in the resin were separated.

First, the resin composition to be treated, which was roughly crushed into blocks having a size of 10 mm square or less, was examined using an apparatus shown in FIG. 3 in which a wet treatment means was arranged after the kneading means. First, the crushed waste plastic was arranged so as to be stably supplied to the hopper, the temperature of the die was set to 200 ° C., and the resin was kneaded. The resin exiting the dice is treated with a solvent, dipropylene glycol n-, in a container (C) for once wet treatment.
After contact with propyl ether at room temperature to extract the flame retardant, the mixture was passed through a cooling water tank and a cutter as usual to obtain pellets.

The residual amount of the flame retardant of the obtained resin was measured by GPC.
It was found that up to 5% could be removed. Further, when the weight average molecular weight of the polystyrene before and after the treatment was examined, no significant difference was found in the change in the molecular weight, and it was found that the recovered polystyrene could be used again as a raw material.
It was also found that 99% of the initial weight of the used solvent can be reused by separately collecting and distilling the solvent.

Example 4 In this example, a HIPS resin composition (weight average molecular weight of resin: 36,000) containing 10 parts by weight of a flame retardant containing tetrabromobisphenol A as a main component was used as waste plastic. The flame retardant component and the resin component contained in this resin were separated.

First, the resin composition to be treated, which was roughly crushed into blocks having a size of 10 mm square or less, was examined using an apparatus shown in FIG. 3 in which a wet treatment means was disposed after the kneading means. First, the crushed waste plastic was arranged so as to be stably supplied to the hopper, the temperature of the die was set to 200 ° C., and the resin was kneaded. The resin exiting the dice is brought into contact with an ethylene glycol solvent heated to 150 ° C. once in a container (C) for wet processing, and after extracting the flame retardant, it is passed through a cooling water tank and a cutting machine as usual. To obtain pellets.

The residual amount of the flame retardant of the obtained resin was measured by GPC.
%. Further, when the weight average molecular weight of the polystyrene before and after the treatment was examined, no significant difference was found in the change in the molecular weight, and it was found that the recovered polystyrene could be used again as a raw material. It was also found that 99% of the initial weight of the used solvent can be reused by separately collecting and distilling the solvent.

[0052]

As described above, by using the treatment method of the present invention, waste plastic containing a flame retardant, which is considered to be a problem in a large amount in the future and becomes a problem, can be easily converted into the original flame retardant and resin. Can be separated. Further, by reusing the resin, the amount of waste can be reduced, and the solvent used for the regeneration can be reused, thereby helping to solve environmental problems required recently.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of the apparatus of the present invention formed by wet means and kneading means.

FIG. 2 is a schematic diagram of the apparatus of the present invention in which a wet processing means is present in a kneader.

FIG. 3 is a schematic view of the apparatus of the present invention in which the wet processing means is disposed after the kneading machine.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 Container for wet processing (A) 2 Resin input port 3 Resin take-out port 4 Solvent injection port (A) 5 Solvent recovery port (A) 6 Extruder 7 Hopper 8 Screw 9 Dice 10 Cooling water tank 11 Cutting machine 12 Collection container 13 Vent 14 Container for wet processing (B) 15 Solvent injection port (B) 16 Solution recovery port (B) 17 Container for wet processing (C)

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hiroshi Onishi 1006 Kazuma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. 72) Inventor Takahiko Terada 1006 Kazuma Kadoma, Kadoma-shi, Osaka Matsushita Electric Industrial Co., Ltd. F-term (reference) 4F301 AA15 AB01 CA04 CA12 CA41 CA62 CA63 CA68 CA72

Claims (6)

[Claims] An apparatus for treating waste plastic containing a flame retardant has a kneading means after a wet means for dissolving at least a part of the flame retardant contained in the waste plastic. Processing equipment. 2. An apparatus for treating waste plastic containing a flame retardant, comprising: means for kneading while dissolving at least a part of the flame retardant contained in the waste plastic. . 3. A flame retardant, wherein the apparatus for treating waste plastic containing a flame retardant has, after the kneading means, wet means comprising an organic solvent for dissolving at least a part of the flame retardant contained in the waste plastic. Waste plastic processing equipment including. 4. The method according to claim 3, wherein the wet means made of an organic solvent for dissolving at least a part of the flame retardant contained in the waste plastic is kept at a temperature not lower than the heat deformation temperature of the resin. Equipment for treating waste plastics containing fuel. 5. The apparatus for treating waste plastic containing a flame retardant according to claim 1, wherein the flame retardant is a bromine-based flame retardant. 6. The apparatus for treating waste plastic containing a flame retardant according to claim 1, wherein the waste plastic is a polymer having a styrene structure.