JP2005238463A - Fire retardant separating method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize a fire retardant separating method for efficiently separating a bromine type fire retardant from a bromine type fire retardant-containing olefinic thermoplastic resin. <P>SOLUTION: A viscosity regulator being an amorphous olefinic resin, which has compatibility with respect to the fire retardant-containing olefinic thermoplastic resin and can lower the viscosity at the time of softening of the fire retardant-containing olefinic thermoplastic resin, is mixed with the fire retardant-containing olefinic thermoplastic resin and the resulting mixture is heated to the softening point of the fire retardant-containing olefinic thermoplastic resin or above to be kneaded while melting both of them. The kneaded fire retardant-containing olefinic thermoplastic resin and the viscosity regulator are sorted into a first layer high in specific gravity and a second layer low in specific gravity and the second layer is taken out to be utilized as an olefinic thermoplastic resin from which the bromine type fire retardant is separated. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a flame retardant separation method for separating a flame retardant from a flame retardant-containing thermoplastic resin used in housings such as refrigerators, copiers, televisions, and computers.

  Various thermoplastic resins such as olefin resins, styrene resins, and ABS (acrylonitrile-butadiene-styrene) resins have been widely used as housing materials for refrigerators, copiers, televisions, computers, and the like.

  However, the thermoplastic resin is highly flammable and may cause fire spread in the event of a fire. Therefore, a flame retardant is added to the thermoplastic resin to prevent the spread of fire. And such a flame retardant containing thermoplastic resin is currently employ | adopted as the material of said various housing | casing.

  For example, halogen-based flame retardants are used worldwide because they have a high anti-combustion effect on various resins and are inexpensive. However, the thermoplastic resin to which the halogen-based flame retardant is added has high flame retardancy, so that it is difficult to incinerate at the time of disposal. Therefore, most of the halogenated flame retardant-containing thermoplastic resins have been disposed of in landfills.

  However, the shortage of landfill sites has become a social problem. For example, with the aim of reducing the amount of landfill disposal, in Japan, the Act on the Recycling of Specified Household Appliances (the Home Appliance Recycling Law) was enacted and entered into force in April 2001. According to this law, recycling (re-commercialization) is mandatory for four household electric appliances such as TVs, refrigerators, washing machines, and air conditioners.

  Well, the waste recycling method includes thermal recycling, which recovers the thermal energy generated when the waste is burned, and combustion or thermal decomposition of the waste to produce valuable materials such as fillers, oil components, and plastic raw materials. There are chemical recycling to collect, material recycling to pulverize, melt and reprocess various molded products. From the viewpoint of prevention of environmental pollution and effective use of resources, material recycling that requires a small amount of landfill disposal is most desirable.

  Therefore, in order to realize material recycling of the flame retardant-containing thermoplastic resin, various methods for separating the flame retardant from the flame retardant-containing thermoplastic resin have been devised.

  For example, in the following Patent Document 1, a flame retardant-containing thermoplastic is obtained by dissolving a flame retardant in an organic solvent by bringing a styrene-based flame retardant-containing thermoplastic resin into contact with an organic solvent such as glycol or glycol ether. A method for separating the flame retardant from the resin is shown.

  Patent Document 2 below discloses a method of separating a flame retardant from a flame retardant-containing thermoplastic resin by dissolving the flame retardant-containing styrene resin in an organic solvent such as cyclohexane.

  Moreover, in the following patent document 3, a flame retardant containing styrene resin is dissolved in an organic solvent such as toluene, and the flame retardant is adsorbed and removed by adding an adsorbent such as a lower alkoxide to the solution. A method for separating a flame retardant from a thermoplastic resin is shown.

  Further, in Patent Document 4 below, after a thermoplastic resin containing a flame retardant is dissolved in a first organic solvent that dissolves both the flame retardant and the thermoplastic resin, the flame retardant dissolves but the thermoplastic resin. A method of separating a flame retardant from a flame retardant-containing thermoplastic resin by adding a second organic solvent that does not dissolve to this solution to precipitate a thermoplastic resin is shown.

  Moreover, in the following patent document 5, a flame retardant-containing polystyrene resin is dissolved in an organic solvent such as methyl ethyl ketone, and the flame retardant and antimony compound dispersed in the solution are centrifuged to remove the flame retardant-containing thermoplastic resin. A method for separating the flame retardant is shown.

  Moreover, in the following patent document 6, a method of separating a flame retardant from a flame retardant-containing thermoplastic resin by continuously bringing a supercritical carbon dioxide gas into contact with the flame retardant-containing thermoplastic resin is shown.

JP 2001-151930 A JP 2003-82154 A JP 2001-131334 A JP 2003-73499 A Japanese Patent Laid-Open No. 2001-19794 JP 2001-19792 A

  According to the techniques of Patent Documents 1 to 5, an organic solvent is used to separate the flame retardant from the flame retardant-containing thermoplastic resin. However, in the method of separating the flame retardant by dissolving the flame retardant-containing thermoplastic resin in an organic solvent, the flame retardant cannot be sufficiently separated in the case of an olefin-based thermoplastic resin (particularly polypropylene resin) that is difficult to dissolve in the organic solvent. There was a problem.

  Moreover, according to the technique of the above-mentioned Patent Document 6, although an organic solvent is not used, expensive equipment is required to generate supercritical carbon dioxide. Further, there is a problem that the processing capability of the flame retardant separation by this technique is low and the cost required for the separation treatment is high.

  The present invention has been made in view of the above circumstances, and even when a flame retardant is contained in an olefin-based thermoplastic resin that is difficult to dissolve in an organic solvent, the flame retardant component and the thermoplastic resin component It is an object of the present invention to provide a flame retardant separation method that can efficiently separate the components at low cost.

  The invention according to claim 1 is compatible with (a) a flame retardant-containing olefinic thermoplastic resin containing a brominated flame retardant and the flame retardant-containing olefinic thermoplastic resin, and contains the flame retardant. A step of preparing a viscosity modifier as an amorphous olefin resin capable of reducing the viscosity at the time of softening of the olefin thermoplastic resin; and (b) the flame retardant-containing olefin thermoplastic resin and the viscosity. A step of kneading the modifier with heating above the softening point of the flame retardant-containing olefinic thermoplastic resin, and (c) the kneaded flame retardant-containing olefinic thermoplastic resin and the viscosity modifier. Are separated into a first layer having a high specific gravity and a second layer having a low specific gravity, and (d) a step of taking out the second layer. The taken out second layer is used as the brominated flame retardant. Olef isolated Flame retardants separation method to obtain a down-based thermoplastic resin.

  The invention according to claim 3 is compatible with (a) a flame retardant-containing olefinic thermoplastic resin containing a brominated flame retardant and the flame retardant-containing olefinic thermoplastic resin, and contains the flame retardant. A step of preparing a viscosity modifier as an amorphous olefin resin capable of reducing the viscosity at the time of softening of the olefin thermoplastic resin; and (b) the flame retardant-containing olefin thermoplastic resin and the viscosity. A step of kneading the modifier with heating above the softening point of the flame retardant-containing olefinic thermoplastic resin, and (c) the kneaded flame retardant-containing olefinic thermoplastic resin and the viscosity modifier. And a step of filtering with an activated carbon filter, and the filtered resin is obtained as an olefinic thermoplastic resin from which the brominated flame retardant has been separated.

  Invention of Claim 4 has compatibility with (a) the flame retardant containing olefinic thermoplastic resin containing a brominated flame retardant, and the said flame retardant containing olefinic thermoplastic resin, and contains the said flame retardant A step of preparing an amorphous olefin-based resin viscosity modifier and activated carbon capable of reducing the viscosity of the olefin-based thermoplastic resin during softening; and (b) the flame retardant-containing olefin-based thermoplastic resin. And a step of kneading together with the activated carbon while heating and melting above the softening point of the flame retardant-containing olefin thermoplastic resin, and (c) the kneaded flame retardant-containing olefin Filtering the thermoplastic resin, the viscosity modifier, and the activated carbon with a filter, and collecting the activated carbon with the filter. The brominated flame retardant is separated from the filtered resin. And a flame retardant separation method for obtaining the olefin thermoplastic resin.

  According to the first aspect of the present invention, the flame retardant-containing olefinic thermoplastic resin and the viscosity modifier are kneaded while melting, and the second layer having a small specific gravity is taken out. Since the specific gravity of the brominated flame retardant is greater than that of the olefinic thermoplastic resin, the brominated flame retardant concentrates in the first layer having a large specific gravity in the flame retardant-containing olefinic thermoplastic resin softened by the viscosity modifier. Therefore, the second layer having a small specific gravity can be obtained as the olefinic thermoplastic resin from which the brominated flame retardant is separated. That is, even when a flame retardant is contained in an olefin-based thermoplastic resin that is difficult to dissolve in an organic solvent, it is difficult to efficiently separate the flame retardant component and the thermoplastic resin component at low cost. A fuel separation method can be realized.

  According to the invention described in claim 3, the flame retardant-containing olefin thermoplastic resin and the viscosity modifier are kneaded while being melted, and filtered through an activated carbon filter. Since brominated flame retardants are easily adsorbed on activated carbon, it is possible to adsorb brominated flame retardants on activated carbon filters by filtering the flame retardant-containing olefinic thermoplastic resin softened with a viscosity modifier through activated carbon filters. . Therefore, the resin after filtration can be obtained as an olefinic thermoplastic resin from which a brominated flame retardant has been separated. That is, even when a flame retardant is contained in an olefin-based thermoplastic resin that is difficult to dissolve in an organic solvent, it is difficult to efficiently separate the flame retardant component and the thermoplastic resin component at low cost. A fuel separation method can be realized.

  According to the fourth aspect of the invention, the flame retardant-containing olefin thermoplastic resin and the viscosity modifier are melted and kneaded including activated carbon, the kneaded material is filtered through a filter, and the activated carbon is captured by the filter. Gather. Since the brominated flame retardant is easily adsorbed on the activated carbon, it is possible to adsorb the brominated flame retardant on the activated carbon by adding activated carbon to the flame retardant-containing olefin thermoplastic resin softened by the viscosity modifier. Therefore, the resin after filtration can be obtained as an olefinic thermoplastic resin from which a brominated flame retardant has been separated. That is, even when a flame retardant is contained in an olefin-based thermoplastic resin that is difficult to dissolve in an organic solvent, it is difficult to efficiently separate the flame retardant component and the thermoplastic resin component at low cost. A fuel separation method can be realized.

  The present invention is a flame retardant separation method for efficiently separating a brominated flame retardant from a flame retardant-containing olefinic thermoplastic resin containing a brominated flame retardant at a low cost.

  Specific examples of the olefin thermoplastic resin in the flame retardant-containing olefin thermoplastic resin in the present invention include polypropylene (PP) resin, polyethylene (PE) resin, polyethylene-polypropylene copolymer (EPDM) resin, and the like. It is done.

  The olefin-based thermoplastic resin may be a single type of composition, for example, only a polypropylene resin, or a mixture of a plurality of types, for example, a mixed composition of a polypropylene resin and a polyethylene resin. It may be a composition.

  The molecular weight of the olefinic thermoplastic resin generally has a weight average molecular weight of 3,000 to 1,000,000, but preferably 10,000 to 8,000,000 in the present invention. Here, when the weight average molecular weight is less than 3000, the thermal properties and mechanical properties of the obtained molded product are lowered, which is not preferable. Moreover, there is no restriction | limiting about molecular weight distribution.

  Examples of the object corresponding to the flame retardant-containing olefinic thermoplastic resin of the present invention include, for example, unnecessary plastic scraps produced in the manufacturing process, resins recovered as waste after being used in housings of home appliances, etc. There are cases that became defective in the process.

  In addition to brominated flame retardants, these flame retardant-containing olefinic thermoplastic resins include non-brominated flame retardants, antioxidants, weathering stabilizers, colorants, plasticizers, flow modifiers, release agents. Various additives such as molds and coating agents may be contained, but the inclusion of these various additives in the present invention does not affect the separation of brominated flame retardants.

  On the other hand, brominated flame retardants in the flame retardant-containing olefin thermoplastic resin in the present invention include bromophenyl ethers such as decabromodiphenyl ether (DeBPE, commonly known as decabro), octabromodiphenyl ether (OBPE), tetrabromodiphenyl ether (TeBPE) and the like. Flame retardants, bromobisphenol A type flame retardants such as tetrabromobisphenol A (TBA), brominated polymers such as brominated polystyrene and brominated syndiotactic polystyrene, hexabromocyclodecane, bistribromophenoxyethane, tri Examples thereof include bromophenol, ethylenebistetrabromophthalimide, TBA polycarbonate oligomer, and TBA epoxy oligomer.

  The brominated flame retardant may be a single type such as only decabromodiphenyl ether as a composition, or may be a mixture of multiple types such as a mixed composition of decabromodiphenyl ether and octabromodiphenyl ether. There may be. In general, the brominated flame retardant is mixed in an amount of about 10 to 30% by weight with respect to the weight of the olefinic thermoplastic resin, but the content of the brominated flame retardant is not limited in the present invention.

  In general, among brominated flame retardants, so-called non-deca types other than decabromodiphenyl ether show good solubility in general-purpose organic solvents (toluene, etc.), whereas decabromodiphenyl ether is insoluble in organic solvents. is there. Olefin-based thermoplastic resins are also insoluble in general-purpose organic solvents.

  Therefore, the flame retardant separation method using an organic solvent as described in Patent Documents 1 to 5 described above is a bromine insoluble in an organic solvent such as decabromodiphenyl ether from a brominated flame retardant-containing olefin thermoplastic resin. Not suitable for separation of flame retardants.

  In the present invention, instead of using an organic solvent, it has compatibility with the flame retardant-containing olefin thermoplastic resin, and may reduce the viscosity when the flame retardant-containing olefin thermoplastic resin is softened. A possible viscosity modifier as an amorphous olefin resin is used. And such a viscosity regulator is grind | pulverized with a flame retardant containing olefin type thermoplastic resin, the mixture of both is heated above the softening point of a flame retardant containing olefin type thermoplastic resin, and it kneads | mixes, making it melt.

  If the flame retardant-containing olefinic thermoplastic resin is heated above the softening point, it softens. However, if a viscosity modifier as described above is added at this time, the viscosity of the flame retardant-containing olefinic thermoplastic resin will decrease. The flame retardant-containing olefin-based thermoplastic resin is dissolved in a semi-liquid state.

  In a flame retardant-containing olefinic thermoplastic resin that has become semi-liquid, if the selection is performed based on the difference in specific gravity, a layer with a small specific gravity can be reused as an olefinic thermoplastic resin from which a brominated flame retardant has been separated. It is possible (Example 1 below). This is because the brominated flame retardant has a higher specific gravity than the olefin thermoplastic resin, and therefore concentrates in a layer having a higher specific gravity in the flame retardant-containing olefin thermoplastic resin softened by the viscosity modifier.

  At this time, the selection by specific gravity may be performed by applying vibration or centrifugal force (for example, applying ultrasonic vibration or centrifugal separation) to the flame retardant-containing olefin-based thermoplastic resin that has become semi-liquid. This is because the selection into a layer having a large specific gravity and a layer having a low specific gravity can be performed with higher accuracy, and the flame retardant component and the thermoplastic resin component can be separated with higher accuracy.

  Brominated flame retardants are easily adsorbed on activated carbon. Therefore, using this property, the flame retardant-containing olefinic thermoplastic resin that has become semi-liquid is filtered through an activated carbon filter, the brominated flame retardant is adsorbed onto the activated carbon filter, and the resin after filtration is brominated. It can be reused as an olefinic thermoplastic resin from which the flame retardant has been separated (Example 2 below).

  Alternatively, activated carbon is added when the viscosity modifier and the flame retardant-containing olefin thermoplastic resin are crushed, and the flame retardant-containing olefin thermoplastic resin and the viscosity modifier are softened. While being heated and melted above the point, the mixture is kneaded while adding activated carbon. Then, the kneaded flame retardant-containing olefin thermoplastic resin, the viscosity modifier and the activated carbon are filtered through a filter, and the activated carbon is collected by the filter. And it is also possible to reuse the filtered resin as an olefinic thermoplastic resin from which brominated flame retardants have been separated by utilizing the property that brominated flame retardants are easily adsorbed on activated carbon (see below). Example 3).

  According to the flame retardant separation method as described above, the flame retardant component and the thermoplastic resin component can be reduced in cost even if the olefin thermoplastic resin that is difficult to dissolve in the organic solvent contains the flame retardant. Can be separated efficiently. In this case, the brominated flame retardant and the olefinic thermoplastic resin can be separated regardless of the type and content of the brominated flame retardant and the type of the olefinic thermoplastic resin.

  In addition, as a viscosity regulator as mentioned above, it has compatibility (complete compatibility) with a flame retardant-containing olefin thermoplastic resin, and lowers the viscosity when the flame retardant-containing olefin thermoplastic resin is softened. An amorphous olefin resin that can be used may be employed. Such an amorphous olefin resin can dramatically reduce the viscosity when the olefin thermoplastic resin is softened.

  Specific examples of the amorphous olefin resin that functions as a viscosity modifier include an amorphous polypropylene resin and an ethylene / α-olefin copolymer having a molecular weight distribution lower than that of a crystalline olefin thermoplastic resin. Specific examples of the amorphous polypropylene resin include atactic polypropylene resin, and specific examples of the ethylene / α-olefin copolymer include ethylene / α-propylene copolymer.

  For example, when the flame retardant-containing olefin-based thermoplastic resin is a polypropylene resin, a low-molecular weight amorphous polypropylene resin having a weight average molecular weight of 10,000 or less, for example, containing atactic polypropylene as a main component may be used. In addition, amorphous polypropylene resin mainly composed of atactic polypropylene is homotype composed of polypropylene alone, block type in which polypropylene is block copolymerized with ethylene, and random copolymerization of polypropylene in ethylene. There are random types.

  For example, when the olefinic thermoplastic resin is a polypropylene resin, the viscosity of the polypropylene resin is about 40,000 to 800,000 St at 180 ° C. The viscosity of the amorphous polypropylene resin mainly composed of atactic polypropylene is about 500 to 2500 cSt at 180 ° C.

  And the viscosity of the mixture which knead | mixed the crystalline polypropylene resin and the amorphous polypropylene resin which has atactic polypropylene as a main component in the weight ratio of 1: 1 will be 1000-10000 cSt at 200 degreeC. Therefore, when a polypropylene resin is dissolved together with an amorphous polypropylene resin mainly composed of atactic polypropylene as a viscosity modifier, the viscosity is dramatically reduced as compared with the case where a polypropylene resin is dissolved alone. I understand.

  The brominated flame retardant particles contained in the flame retardant-containing olefin thermoplastic resin are not dissolved in the olefin thermoplastic resin, but are chemically bonded to the olefin thermoplastic resin. Do not mean. That is, the brominated flame retardant particles are kneaded when the olefinic thermoplastic resin is melted, dispersed in the resin matrix, and entangled with the molecular chain of the olefinic thermoplastic resin.

  Therefore, if a viscosity modifier is added to the flame retardant-containing olefin thermoplastic resin as described above to bring the flame retardant-containing olefin thermoplastic resin into a molten state and the viscosity is lowered, the brominated flame retardant particles are removed from the olefin-based heat. The molecular chain of the plastic resin can be free from entanglement. At this time, if the difference in specific gravity is utilized as described above, or if it is adsorbed on an activated carbon filter or activated carbon, it becomes possible to separate the brominated flame retardant from the flame retardant-containing olefin thermoplastic resin. It is.

  For example, an amorphous polypropylene resin mainly composed of atactic polypropylene is soluble in an organic solvent. Therefore, when a non-crystalline polypropylene resin mainly composed of atactic polypropylene is mixed with a crystalline polypropylene resin, which is a flame retardant-containing olefin thermoplastic resin, as a viscosity modifier, an organic solvent insoluble in an organic solvent is converted into an organic solvent. An amorphous polypropylene resin soluble in a solvent can be separated by centrifugation or the like.

  That is, after separating the brominated flame retardant, an organic solvent such as toluene or ethyl acetate is added to the crystalline polypropylene resin / amorphous polypropylene resin mixture, and the crystalline polypropylene resin and the amorphous are separated by centrifugation. And separated into an organic solvent in which a soluble polypropylene resin is dissolved. The organic solvent may be subjected to steam stripping with a solvent recovery device to deposit the amorphous polypropylene resin in hot water. At this time, the amorphous polypropylene resin is recovered as a hydrated product, but can be reused as atactic polypropylene by being sufficiently dried.

  Moreover, in addition to the flame retardant separation method using the viscosity modifier as described above, a flame retardant separation method using an organic solvent may be used in combination. That is, for example, in the flame retardant separation method using the difference in specific gravity, a flame retardant separation method using an organic solvent is further used in combination with a layer having a large specific gravity after separation (a resin layer containing a large amount of brominated flame retardant). The separation accuracy may be increased.

  The amorphous polypropylene resin and the non-deca type brominated flame retardant are soluble in organic solvents such as toluene and ethyl acetate. Therefore, when a non-deca type brominated flame retardant migrates from a crystalline polypropylene resin as a flame retardant-containing olefin thermoplastic resin into an amorphous polypropylene resin as a viscosity modifier, the amorphous polypropylene resin and It is possible to extract the brominated flame retardant from the crystalline polypropylene resin.

  Since non-deca type brominated flame retardants are soluble in water and non-crystalline polypropylene resin is insoluble in water, amorphous polypropylene resin and non-deca type bromine using water. It is possible to deposit an amorphous polypropylene resin from a mixture of flame retardants.

  In addition, decabro bromine flame retardants are insoluble in organic solvents, but crystalline polypropylene resins (also insoluble in organic solvents) that are flame retardant-containing olefinic thermoplastic resins come into contact with organic solvents. At the time of crystallization, the decabro type brominated flame retardant which is a foreign substance is excluded, and at this point, the decabro type brominated flame retardant and the crystalline polypropylene resin are crystallized separately. Therefore, the crystallized decabro-type brominated flame retardant and the crystallized crystalline polypropylene resin can be separated by, for example, sorting based on the difference in specific gravity using water.

  For example, when the amorphous polypropylene resin is mixed with the crystalline polypropylene resin after removing the brominated flame retardant, the viscosity remains low even after cooling. Therefore, a high-viscosity resin is added to regenerate the viscosity, or a crystalline polypropylene resin mixed with an amorphous polypropylene resin is used as an elastomer as it is, or a modifier that improves the toughness of the crystalline polypropylene resin ( Since amorphous polypropylene resin has high toughness, it may be used as

  Further, in the present invention, when the olefinic thermoplastic resin after removing the brominated flame retardant is recovered and material recycled, the plasticizer, mold release agent, antioxidant, flame retardant, flame retardant aid, Additives such as dyes, pigments and antistatic agents can be blended in the olefinic thermoplastic resin. In addition, about each said additive, you may use only the 1 type individually or in combination of 2 or more types.

  As a plasticizer, for example, polyethylene glycol, polyamide oligomer, ethylene bisstearoamide, phthalic acid ester, adipic acid ester, polystyrene oligomer, polyethylene wax, silicone oil, mineral oil, etc. Can do.

  As the release agent, for example, a known one such as polyethylene wax, silicone oil, long chain carboxylic acid, long chain carboxylic acid metal salt and the like can be selected and used.

  Examples of antioxidants include 2,6-di-t-butyl-p-cresol, tetrakis- [methylene-3- (3 ′, 5′-di-t-butyl-4′-hydroxyphenyl) propionate] methane , Stearyl-β- (3,5-di-t-butyl-4-hydroxyphenyl) propionate, 1,3,5-trimethyl-2,4,6-tris (3,5-cy-t-butyl-4 Phenols such as -hydroxybenzyl) benzene, triethylene glycol-bis [3- (3-t-butyl-5-methyl-4-hydroxyphenyl) propionate], tris (2,4-di-t-butylphenyl) It can be arbitrarily selected from known ones such as phosphorous such as phosphite and sulfur such as dilauryl-3,3′-thiodipropionate.

  As the flame retardant, for example, a known flame retardant such as tricresyl phosphate, triphenyl phosphate, tris-3-chloropropyl phosphate and the like can be arbitrarily selected and used. Although it is possible to add the brominated flame retardant again, the brominated flame retardant is separated for the purpose of environmental protection, and therefore it is not desirable to add it again.

  The flame retardant aid can be arbitrarily selected from antimony compounds such as antimony trioxide and other known materials.

  This example is a flame retardant separation method in which a brominated flame retardant is separated by a difference in specific gravity in a flame retardant-containing olefin thermoplastic resin that has become semi-liquid.

  FIG. 1 is a flowchart showing a flame retardant separation method according to the present embodiment. Moreover, FIG. 2 is a figure which shows the flame retardant separation apparatus used in the flame retardant separation method based on a present Example.

  As shown in FIG. 1 and FIG. 2, in this example, it was difficult to add decabromodiphenyl ether (specific gravity: 3.02, addition amount of 20% by weight to the weight of the olefin thermoplastic resin) as a brominated flame retardant. Polypropylene resin (resin weight average molecular weight 35000) as a flame retardant-containing olefin-based thermoplastic resin FP and atactic polypropylene resin (resin weight average molecular weight 1000 to 5000 as a viscosity modifier VS) The amount of 40 wt% based on the weight of the thermoplastic resin) was prepared, and decabromodiphenyl ether was separated from the polypropylene resin.

  First, the flame retardant-containing polypropylene resin and the atactic polypropylene resin are crushed so as to have a diameter of about 8 to 15 mm, and the crushed pieces are mixed (step S1 in FIG. 1). At this time, in order to improve the dispersibility of the atactic polypropylene resin pulverized piece in the flame retardant-containing polypropylene resin pulverized piece, a tumbler or a three-hands mixer (both have devices manufactured by Nihon Seam Co., Ltd.), etc. It may be used.

  Next, a mixture of the atactic polypropylene resin pulverized piece and the flame retardant-containing polypropylene resin pulverized piece is supplied to the inlet of the hopper HP of the flame retardant separating apparatus of FIG. The supplied mixture is fed into the kneading tank KD connected to the hopper HP.

  In the kneading tank KD, by adjusting the cylinder temperature to 200 to 220 ° C. and rotating the screw SC, the atactic polypropylene resin crushed pieces and the flame retardant-containing polypropylene resin crushed pieces are softened. Kneading while heating and melting above the point (step S2 in FIG. 1).

  The viscosity of the flame retardant-containing polypropylene resin is about 50,000 to 550000 St at 200 to 220 ° C. The viscosity of the atactic polypropylene resin is about 10 to 100 cSt at 200 to 220 ° C. As described above, when the temperature of the cylinder is adjusted to 200 to 220 ° C. in the kneading tank KD, the viscosity of the mixture of the flame retardant-containing polypropylene resin and the atactic polypropylene resin becomes about 2000 cSt, and a dramatic decrease in viscosity is obtained. The mixture of the flame retardant-containing polypropylene resin and the atactic polypropylene resin became semi-liquid.

  As the kneading tank KD, an apparatus capable of continuous melting and kneading, such as an extruder having a single or biaxial screw, an injection molding machine, and a blow molding machine (for example, an apparatus manufactured by Nippon Steel Works, Ltd.). Existing).

  A mixture of the flame retardant-containing polypropylene resin and atactic polypropylene resin melted and kneaded in the kneading tank KD is sent to a sorting tank ST connected to the kneading tank KD.

  In the sorting tank ST, vibration (for example, ultrasonic vibration) or centrifugal force is applied to the mixture to sort into a first layer having a high specific gravity and a second layer having a low specific gravity (step S3 in FIG. 1). Specifically, for example, the mixture is vibrated to cause decabromodiphenyl ether, which is a brominated flame retardant having a large specific gravity, to settle in the lower layer of the sorting tank ST, and a polypropylene resin having a low specific gravity and an atactic polypropylene resin are floated on the upper layer. .

  As an apparatus capable of applying a vibration, for example, an apparatus manufactured by Chiyoda Electric Co., Ltd. exists, and as an apparatus capable of performing centrifugal separation by applying a centrifugal force, an apparatus manufactured by Beckman Coulter, for example, exists.

  Each mixture of the upper layer and the lower layer sorted in the sorting tank ST is sent to the separation tank SP. And the upper layer component (it becomes resin component RS1 from which the flame retardant was removed) with a small specific gravity was taken out by extrusion of the screw SC from the upper layer outlet OT1 provided in the separation vessel SP, and provided in the separation vessel SP. A lower layer component having a large specific gravity (resin component RS2 containing a large amount of flame retardant) is taken out from the lower layer outlet OT2 by pushing out the screw SC (step S4 in FIG. 1).

  And the resin component RS1 of the upper layer from which the flame retardant has been removed is cooled and recovered to obtain pellets (step S5 in FIG. 1). The upper layer resin component RS1 taken out in this way is reused as an olefinic thermoplastic resin from which the brominated flame retardant has been separated. In addition, as an apparatus which can be cooled and pelletized, for example, there is an apparatus manufactured by Seiwa Iron Works.

  When the residual amount of the flame retardant in the resin thus obtained was measured with a fluorescent X-ray analyzer, it was found that it was removed to about 12% when the initial flame retardant content was 100%. And it turned out that a flame retardant can be removed to about 4% by repeating the flow of said step S1-S5 once more.

  For the lower layer resin component RS2 containing a large amount of brominated flame retardant, an organic solvent is used to precipitate decabromodiphenyl ether and polypropylene resin insoluble in the organic solvent. Then, the crystallized decabromodiphenyl ether and the crystallized polypropylene resin are separated by performing sorting based on the difference in specific gravity using water. The atactic polypropylene resin dissolved in the organic solvent is precipitated from the organic solvent using water.

  In this way, decabromodiphenyl ether which is a brominated flame retardant is recovered, and the separated polypropylene resin which is an olefinic thermoplastic resin and atactic polypropylene resin which is an amorphous polypropylene resin are reused.

  Thus, since the specific gravity of the brominated flame retardant is larger than that of the olefinic thermoplastic resin, the brominated flame retardant concentrates in the first layer having a large specific gravity in the flame retardant-containing olefinic thermoplastic resin softened by the viscosity modifier. Therefore, the second layer having a small specific gravity can be obtained as the olefinic thermoplastic resin from which the brominated flame retardant is separated. That is, even when a flame retardant is contained in an olefin-based thermoplastic resin that is difficult to dissolve in an organic solvent, it is difficult to efficiently separate the flame retardant component and the thermoplastic resin component at low cost. A fuel separation method can be realized.

  This example is a modification of the flame retardant separation method according to Example 1, and is not a difference in specific gravity, but a flame retardant separation method in which a brominated flame retardant is separated by adsorbing a brominated flame retardant on an activated carbon filter. It is.

  FIG. 3 is a flowchart showing the flame retardant separation method according to the present embodiment. Moreover, FIG. 4 is a figure which shows the flame retardant separation apparatus used in the flame retardant separation method based on a present Example.

  As shown in FIG. 3 and FIG. 4, even in this example, it was difficult to add decabromodiphenyl ether (specific gravity: 3.02, addition amount of 20 wt% with respect to the weight of the olefin thermoplastic resin) as a brominated flame retardant. Polypropylene resin (resin weight average molecular weight 35000) as a flame retardant-containing olefin-based thermoplastic resin FP and atactic polypropylene resin (resin weight average molecular weight 1000 to 5000 as a viscosity modifier VS) The amount of 40 wt% based on the weight of the thermoplastic resin) was prepared, and decabromodiphenyl ether was separated from the polypropylene resin.

  3 and 4, until the step of kneading the atactic polypropylene resin pulverized piece and the flame retardant-containing polypropylene resin pulverized piece while heating and melting them above the softening point of the flame retardant-containing polypropylene resin, FIG. 1 and FIG. This is the same as the case of 2.

  However, the sorting tank ST and the separation layer SP are not connected to the kneading tank KD of this embodiment, but instead, an activated carbon filter AF is provided near the take-out port OT3 of the kneading tank KD. As such an activated carbon filter AF, for example, an activated carbon filter sheet (manufactured by Unitika Ltd.) combined with a screen mesh filter (manufactured by Higashida Wire Mesh Co., Ltd.) or activated carbon fibers (manufactured by Unitika Ltd.) may be employed. .

  A mixture of the atactic polypropylene resin kneaded in the kneading tank KD and the flame retardant-containing polypropylene resin is filtered by the activated carbon filter AF. At this time, decabromodiphenyl ether, which is a brominated flame retardant, is adsorbed to the activated carbon filter AF (step S3a in FIG. 3).

  Then, the filtered resin from which decabromodiphenyl ether has been separated is taken out by extrusion of the screw SC from the take-out port OT3 of the kneading tank KD (step S4 in FIG. 3).

  Thereafter, the resin component taken out is cooled and collected to obtain pellets (step S5 in FIG. 3). The resin component thus taken out is reused as an olefinic thermoplastic resin from which the brominated flame retardant has been separated.

  When the residual amount of the flame retardant in the resin thus obtained was measured with a fluorescent X-ray analyzer, it was found that when the initial flame retardant content was 100%, it could be removed to about 20%. Further, it was found that the flame retardant can be removed to about 6% by repeating the flow of each of the above steps once more.

  The activated carbon filter that adsorbs brominated flame retardants can be removed from brominated flame retardants without burning brominated dioxins by burning at a temperature of 1000 ° C or higher. be able to.

  In this way, brominated flame retardants are easily adsorbed on activated carbon, so if the flame retardant-containing olefinic thermoplastic resin softened with a viscosity modifier is filtered through an activated carbon filter, the brominated flame retardant can be adsorbed on the activated carbon filter. Is possible. Therefore, the resin after filtration can be obtained as an olefinic thermoplastic resin from which a brominated flame retardant has been separated. That is, even when a flame retardant is contained in an olefin-based thermoplastic resin that is difficult to dissolve in an organic solvent, it is difficult to efficiently separate the flame retardant component and the thermoplastic resin component at low cost. A fuel separation method can be realized.

  This example is a modification of the flame retardant separation method according to Example 2, and a screen mesh filter that does not contain activated carbon is provided instead of activated carbon filter, and activated carbon is used as a flame retardant-containing olefin-based thermoplastic resin and viscosity modifier. This is a flame retardant separation method in which a brominated flame retardant is separated by first mixing and pulverizing, adsorbing the brominated flame retardant on activated carbon, and collecting the activated carbon with a screen mesh filter.

  FIG. 5 is a flowchart showing the flame retardant separation method according to the present embodiment. Moreover, FIG. 6 is a figure which shows the flame retardant separation apparatus used in the flame retardant separation method based on a present Example.

  As shown in FIG. 5 and FIG. 6, even in this example, it was difficult to add decabromodiphenyl ether (specific gravity: 3.02, addition amount of 20 wt% with respect to the weight of the olefin thermoplastic resin) as a brominated flame retardant. Polypropylene resin (resin weight average molecular weight 35000) as a flame retardant-containing olefin-based thermoplastic resin FP and atactic polypropylene resin (resin weight average molecular weight 1000 to 5000 as a viscosity modifier VS) The amount of 40 wt% based on the weight of the thermoplastic resin) was prepared, and decabromodiphenyl ether was separated from the polypropylene resin.

  As shown in FIG. 5 and FIG. 6, activated carbon AC (addition amount of 10% by weight with respect to the weight of the olefinic thermoplastic resin) is mixed with the flame retardant-containing olefinic thermoplastic resin and the viscosity modifier, and hopper HP is mixed. In

  5 and 6, until the step of kneading the atactic polypropylene resin pulverized piece and the flame retardant-containing polypropylene resin pulverized piece while heating and melting above the softening point of the flame retardant-containing polypropylene resin, FIG. 3 and FIG. This is the same as the case of 4. However, since the activated carbon AC is also put into the hopper HP, the kneading tank KD is kneaded including the activated carbon AC. At this time, decabromodiphenyl ether, which is a brominated flame retardant, is adsorbed on the activated carbon AC.

  In the kneading tank KD of this embodiment, a screen mesh filter FT is provided in the vicinity of the take-out port OT3 of the kneading tank KD instead of the activated carbon filter AF. Then, the kneaded atactic polypropylene resin, the flame retardant-containing polypropylene resin and the activated carbon are filtered by the screen mesh filter FT, and the activated carbon is collected by the screen mesh filter FT (step S3b in FIG. 5).

  Since the activated carbon has a particle size of about 2.36 to 0.50 mm, the mesh width of the screen mesh filter FT may be smaller than this. As such a screen mesh filter FT, for example, a product manufactured by Higashida Wire Mesh Co., Ltd. exists.

  Then, the filtered resin from which decabromodiphenyl ether has been separated is taken out by extrusion of the screw SC from the take-out port OT3 of the kneading tank KD (step S4 in FIG. 5).

  Thereafter, the resin component taken out is cooled and collected to obtain pellets (step S5 in FIG. 5). The resin component thus taken out is reused as an olefinic thermoplastic resin from which the brominated flame retardant has been separated.

  When the residual amount of the flame retardant in the resin thus obtained was measured with a fluorescent X-ray analyzer, it was found that it was removed to about 22% when the initial flame retardant content was 100%. Further, it was found that the flame retardant can be removed to about 10% by repeating the flow of the above steps once more.

  Note that brominated flame retardant removal treatment can be performed on brominated flame retardant adsorbed activated carbon collected by the screen mesh filter FT without burning brominated dioxins by burning at a temperature of 1000 ° C. or higher. It can be used again as activated carbon.

  In this way, brominated flame retardants are easy to adsorb on activated carbon, so if activated carbon is added to a flame retardant-containing olefin thermoplastic resin softened by a viscosity modifier, brominated flame retardant can be adsorbed on activated carbon. is there. Therefore, the resin after filtration can be obtained as an olefinic thermoplastic resin from which a brominated flame retardant has been separated. That is, it is difficult to efficiently separate the flame retardant component and the thermoplastic resin component at low cost even when the flame retardant is contained in the olefinic thermoplastic resin that is difficult to dissolve in the organic solvent. A fuel separation method can be realized.

2 is a flowchart illustrating a flame retardant separation method according to Example 1. It is a figure which shows the flame retardant separation apparatus used with the flame retardant separation method which concerns on Example 1. FIG. 6 is a flowchart illustrating a flame retardant separation method according to a second embodiment. It is a figure which shows the flame retardant separation apparatus used with the flame retardant separation method which concerns on Example 2. FIG. 6 is a flowchart illustrating a flame retardant separation method according to a third embodiment. It is a figure which shows the flame retardant separation apparatus used with the flame retardant separation method which concerns on Example 3. FIG.

Explanation of symbols

FP Flame retardant-containing olefin thermoplastic resin, VS viscosity modifier, HP hopper, KD kneading tank, SC screw, ST sorting tank, SP separation tank, AF activated carbon filter, AC activated carbon, FT filter.

Claims (4)

(A) having compatibility with a flame retardant-containing olefinic thermoplastic resin containing a brominated flame retardant and the flame retardant-containing olefinic thermoplastic resin, and at the time of softening of the flame retardant-containing olefinic thermoplastic resin Preparing a viscosity modifier that is an amorphous olefin resin capable of lowering the viscosity;
(B) a step of kneading the flame retardant-containing olefinic thermoplastic resin and the viscosity modifier while heating and melting them above the softening point of the flame retardant-containing olefinic thermoplastic resin;
(C) selecting the kneaded flame retardant-containing olefinic thermoplastic resin and the viscosity modifier into a first layer having a large specific gravity and a second layer having a small specific gravity;
(D) removing the second layer,
A flame retardant separation method for obtaining the extracted second layer as an olefinic thermoplastic resin from which the brominated flame retardant has been separated. The flame retardant separation method according to claim 1,
The selection in the step (c) is a flame retardant separation method in which vibration or centrifugal force is applied to the kneaded flame retardant-containing olefin thermoplastic resin and the viscosity modifier. (A) having compatibility with a flame retardant-containing olefinic thermoplastic resin containing a brominated flame retardant and the flame retardant-containing olefinic thermoplastic resin, and at the time of softening of the flame retardant-containing olefinic thermoplastic resin Preparing a viscosity modifier that is an amorphous olefin resin capable of lowering the viscosity;
(B) a step of kneading the flame retardant-containing olefinic thermoplastic resin and the viscosity modifier while heating and melting them above the softening point of the flame retardant-containing olefinic thermoplastic resin;
(C) filtering the kneaded flame retardant-containing olefinic thermoplastic resin and the viscosity modifier with an activated carbon filter,
A flame retardant separation method for obtaining a resin after filtration as an olefin thermoplastic resin from which the brominated flame retardant has been separated. (A) having compatibility with a flame retardant-containing olefinic thermoplastic resin containing a brominated flame retardant and the flame retardant-containing olefinic thermoplastic resin, and at the time of softening of the flame retardant-containing olefinic thermoplastic resin A step of preparing a viscosity modifier, which is an amorphous olefin resin, capable of lowering the viscosity, and activated carbon;
(B) a step of kneading the flame retardant-containing olefinic thermoplastic resin and the viscosity modifier together with the activated carbon while heating and melting the softener above the flame retardant-containing olefinic thermoplastic resin; ,
(C) filtering the kneaded flame retardant-containing olefin-based thermoplastic resin, the viscosity modifier, and the activated carbon with a filter, and collecting the activated carbon with the filter,
A flame retardant separation method for obtaining a resin after filtration as an olefin thermoplastic resin from which the brominated flame retardant has been separated.

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