JP4685728B2 - Raw material recovery method for lead-containing soft polyvinyl chloride material - Google Patents

Description

  The present invention relates to a raw material recovery method for a lead-containing soft polyvinyl chloride material, and more particularly, for example, separation of a polyvinyl chloride resin, a plasticizer, and a lead compound from a lead-containing soft polyvinyl chloride material containing a lead component. The present invention relates to a raw material recovery method for a lead-containing soft polyvinyl chloride material that can be recovered.

  Examples of a method for recovering the raw material from the polyvinyl chloride-based recovered material that has become a waste material include the methods described in Patent Document 1 and Patent Document 2.

The invention described in Patent Document 1 states that “in the method for recovering lead contained in plastic waste containing chlorine-based polymer, a residue obtained by pyrolyzing the plastic waste, or the residue and the residue After extracting lead from an oil produced by pyrolysis with an aqueous solution of acid or chelating agent that forms a salt or complex with high solubility with lead, an alkali is added to the extract and the carbonate reacts with lead to react with it. A method for recovering lead in plastic waste, wherein the gas to be formed is blown, and the extracted lead is precipitated as basic lead carbonate and separated and recovered (see claim 1 of Patent Document 1). According to the invention described in Patent Document 1, “In the lead recovery method of the present invention, dry distillation and thermal decomposition of plastic waste containing polyvinyl chloride and the like used in home appliances such as air conditioner indoor units and refrigerators” The lead in the residue is extracted with an aqueous solution of acid or chelating agent (in some cases, water), and this extract is reacted with lead such as carbon dioxide in the presence of alkali to form carbonate. By blowing in the gas, lead can be precipitated as basic lead carbonate that is stable and highly useful in water, and can be recovered at a very high rate. By doing so, it is possible to drastically improve the environment for disposal or reuse of residues and the safety for workers. ” See Effect column the invention of Patent Document 1).

  The method described in Patent Document 1 requires the use of an “acid or chelating agent that forms a highly soluble salt or complex with lead”, and also thermally decomposes plastic waste containing chlorinated polymers. It is considered that chlorinated polymers such as polyvinyl chloride resin cannot be recovered to the extent that they can be used.

  On the other hand, the invention described in Patent Document 2 is “dissolving the waste coating material of the vinyl chloride coated electric wire in a solvent, removing calcium and lead from the solution as a precipitate by centrifugation, and removing the solution from which the precipitate has been removed. Distillation to separate the solvent and the vinyl chloride resin, and the vinyl chloride resin is pyrolyzed in a pyrolysis furnace at 300 ° C to 450 ° C to remove chlorine. Chlorine treatment method ”(see claim 1 of Patent Document 2). According to this Patent Document 2, there is a description that “the coated waste material made of vinyl chloride resin is finely cut and dissolved in a solvent” (see Paragraph No. 0006 of Patent Document 2). There is only a description that “this sample is finely pulverized and dissolved in 10 times the amount of THF relative to the sample amount” (see Example 1 of Patent Document 2). There is no. With chemical common sense, it will take a very long time to dissolve polyvinyl chloride resin in THF at room temperature, and it may be necessary to heat it to near the boiling point of THF to shorten the dissolution time. It is done. Furthermore, this patent document 2 does not describe the recovery of the plasticizer from the waste coating material of the vinyl chloride coated electric wire.

JP-A-9-234447 JP 2000-285766 A

  The problem to be solved by the present invention is to provide a method for recovering a lead component, a plasticizer, and a polyvinyl chloride resin not containing them from a recovered product of a lead-containing soft polyvinyl chloride product.

As means for solving the problems,
Claim 1
And lead-containing soft polyvinyl chloride le Material, the lead-containing soft poly and carbon dioxide in a supercritical state above 100 parts by weight with respect to the vinyl chloride material 100 parts by mass, the lead-containing soft polyvinyl chloride material 100 parts by weight The solid obtained by contacting 20 to 100 parts by mass with an aliphatic alcohol having 1 to 3 carbon atoms , recovering the plasticizer from the liquid component in the supercritical state, and releasing the supercritical state a raw material recovery how the lead-containing soft polyvinyl chloride le-containing material and recovering a lead compound by adding a surfactant to the object.

Raw material recovery method of a lead-containing soft polyvinyl chloride le Material of the present invention (hereinafter, simply referred to as "raw material recovery method of the invention".), The carbon dioxide under supercritical conditions, lead-containing soft and polyvinyl chloride le material, separated from contacting the aliphatic alcohols having 1 to 3 carbon atoms in a liquid component and a solid in a supercritical state. By releasing the supercritical state of the liquid component in the supercritical state, the liquid component is taken out and the plasticizer is separated from the liquid component. If a liquid substance remains together with the solid substance, solid content including a polyvinyl chloride resin and a lead compound is obtained by solid-liquid separation. The lead compound can be separated from the liquid obtained by mixing the obtained solid content and the surfactant and performing solid-liquid separation. The remaining solid component is a polyvinyl chloride resin component from which the plasticizer and lead compound have been removed. Thus, according to the present invention, a lead-containing soft polyvinyl chloride le Material, high purity and a polyvinyl chloride resin and a lead compound and a plasticizer can be easily separated in the lead-containing soft polyvinyl chloride Le Material A raw material recovery method can be provided.

  In addition, since the raw material recovery method of the present invention is not an incineration process, dioxins are not generated, and since it is not a landfill disposal, there is no soil contamination, and the environment is not adversely affected.

  Furthermore, according to the present invention, since the recovered polyvinyl chloride resin, plasticizer and lead compound can be reused, the amount of waste generated is reduced, and the cost increases due to disposal of waste and secondary Environmental pollution can be prevented.

  The object to be processed by the raw material recovery method of the present invention is a lead-containing soft polyvinyl chloride material. This lead-containing soft polyvinyl chloride material is a lead-containing soft polyvinyl chloride resin composition containing a lead compound, a plasticizer and a polyvinyl chloride resin, which is recovered without being used as a product, Collected half-finished products such as burrs and punching residues produced as a by-product when molding using lead-containing soft polyvinyl chloride resin composition, molding using the lead-containing soft polyvinyl chloride resin composition The lead-containing soft polyvinyl chloride product obtained in this way is collected and discarded, or the lead-containing soft polyvinyl chloride product is combined with a resin product obtained using another resin. Examples of the product include lead-containing soft polyvinyl chloride-based materials that are assembled products that have been discarded and separated from the collected products of the assembled products.

  Further, the lead-containing soft polyvinyl chloride material can be provided to the raw material recovery method of the present invention as it is when recovered. If the purpose is to recover additives such as plasticizers and lead compounds from lead-containing soft polyvinyl chloride materials in a short time, the lead-containing soft polyvinyl chloride material was crushed or crushed. Then, it is good to use for the raw material collection | recovery method of this invention as a ground material or a crushed material.

  As the vinyl chloride resin in the lead-containing soft polyvinyl chloride resin composition, vinyl chloride resin, vinyl chloride vinyl acetate copolymer resin, vinyl chloride vinylidene chloride copolymer resin, vinyl chloride acrylate ester, vinyl chloride methacrylate copolymer Examples thereof include resins, vinyl chloride acrylonitrile copolymers, ethylene vinyl chloride copolymers, and propylene vinyl chloride copolymers. Among these, a lead-containing soft vinyl chloride resin having a large content of additives such as a plasticizer and a lead compound is suitable as an application target of the raw material recovery method of the present invention.

  The various vinyl chloride resins may be linear polymers or branched polymers.

  In this invention, among the lead-containing soft polyvinyl chloride resin compositions containing various vinyl chloride resins and various additives, a lead-containing soft polyvinyl chloride resin composition having an elongation at break of at least 50%. preferable. In order to make the elongation at break the above-mentioned value, a large amount of additive must be added to the resin, and the recovered material of the lead-containing soft polyvinyl chloride resin composition containing such a large amount of additive is this. By applying the raw material recovery method of the invention, additives, particularly plasticizers, and lead compounds can be advantageously recovered.

  Examples of additives contained in the lead-containing soft polyvinyl chloride resin composition include plasticizers, waxes, stabilizers, ultraviolet absorbers, reinforcing agents, flame retardants, antistatic agents, colorants, lubricants, foaming agents, etc. Can be mentioned.

  The plasticizer is not particularly limited. For example, phthalate ester plasticizer, phosphate ester plasticizer, adipate ester plasticizer, sebate ester plasticizer, azelaate ester plasticizer, citrate ester plasticizer Glycolic acid ester plasticizer, trimellitic acid ester plasticizer, phthalic acid isomer ester plasticizer, ricinol ester plasticizer, polyester type plasticizer, epoxy plasticizer and the like. Among these plasticizers, if the purpose is to efficiently recover the plasticizer with high purity, the plasticizer contained in the lead-containing soft polyvinyl chloride composition is a phthalate plasticizer. Good. Examples of the phthalate ester plasticizer include dimethyl phthalate, diethyl phthalate, dibutyl phthalate, dihexyl phthalate, di (n-octyl) phthalate, di (2-ethylhexyl) phthalate, diisooctyl phthalate, dicapryl phthalate, dinonyl phthalate, Diisononyl phthalate, didecyl phthalate, diisodecyl phthalate, diundecyl phthalate, ditridecyl phthalate, dibenzyl phthalate, dicyclohexyl phthalate, butyl benzyl phthalate, octyl decyl phthalate, butyl octyl phthalate, octyl benzyl phthalate, (n-hexyl) (n-decyl) ) Phthalate, (n-octyl) (n-decyl) phthalate, and the like.

  Since the lead-containing soft polyvinyl chloride resin composition usually contains an additive in a proportion of 30 parts by mass or more and 100 parts by mass or less with respect to 100 parts by mass of the vinyl chloride resin, the lead-containing soft polyvinyl chloride resin composition When the vinyl chloride resin composition is applied to the raw material recovery method of the present invention, the additive can be recovered advantageously, and the object of the raw material recovery method of the present invention can be sufficiently achieved.

  Examples of the lead compound contained in the lead-containing soft polyvinyl chloride resin composition include a lead stabilizer. Examples of the lead stabilizer include lead stearate, dibasic lead stearate, and lead naphthenate. These lead stearate, dibasic lead stearate, lead naphthenate and the like may be contained in the soft polyvinyl chloride resin composition under a name other than the lead-based stabilizer.

  In the raw material recovery method of the present invention, an alcohol solvent is used. As the alcohol solvent, methanol and ethylene glycol are preferable because the extraction efficiency of the plasticizer is increased. The selection of the alcohol solvent is not particularly limited as long as the object of the present invention can be achieved, but is preferably an aliphatic alcohol solvent and a polyhydric alcohol, and is preferably a lower group having 1 to 5 carbon atoms. An aliphatic alcohol solvent and a glycol having 2 to 5 carbon atoms are more preferable. Examples of the lower aliphatic alcohol solvent having 1 to 5 carbon atoms include methanol, ethanol, propanol, butanol, and pentanol. Examples of polyhydric alcohols having 2 to 5 carbon atoms include ethylene glycol and propylene glycol.

  The amount of the alcohol solvent used is not particularly limited as long as the plasticizer can be extracted. For example, the alcohol solvent is 20 parts by mass or more and 50 parts by mass with respect to 100 parts by mass of the lead-containing soft polyvinyl chloride material. It is preferable that it is below mass parts. However, the amount of the alcohol solvent is not limited to 20 parts by mass or more and 50 parts by mass or less as long as it is within the range of 20 parts by mass or more and 100 parts by mass or less. If used in less than 20 parts by mass of alcohol solvent, the plasticizer may not be extracted efficiently. If used in excess of 100 parts by mass of alcohol solvent, the solubility of the alcohol solvent in carbon dioxide in a supercritical state decreases, leading to In some cases, it does not function sufficiently as a solvent that can efficiently extract the additive from the contained soft polyvinyl chloride material.

  Although the usage-amount of a carbon dioxide is not specifically limited, For example, 100 mass parts or more of carbon dioxide and 500 mass parts or less are suitable with respect to 100 mass parts of lead containing soft polyvinyl chloride-type raw materials. However, the amount of carbon dioxide is not limited to an amount of 100 parts by mass or more and 500 parts by mass or less as long as the amount of carbon dioxide is in the range of 100 parts by mass or more and 1000 parts by mass or less. If used in less than 100 parts by mass of carbon dioxide, the plasticizer may not be extracted efficiently. If used in excess of 1000 parts by mass of carbon dioxide, the mass ratio between the lead-containing soft polyvinyl chloride material and carbon dioxide becomes too large. As a result, the equipment cost increases due to the increase in the size of the processing equipment, and the plasticizer may not be recovered at low cost from the lead-containing soft polyvinyl chloride material.

  First, in the raw material recovery method of the present invention, the lead-containing soft polyvinyl chloride material and the alcohol solvent are brought into contact under a supercritical state of carbon dioxide. In the raw material recovery method of the present invention, the method of bringing the lead-containing soft polyvinyl chloride material and the alcohol solvent into contact with each other under the supercritical state of carbon dioxide is particularly suitable as long as the object of the present invention can be achieved. It is not limited. As a method of contacting, for example, in the supercritical state of carbon dioxide, the alcohol solvent is brought into contact with the lead-containing soft polyvinyl chloride material, and the solvent is brought into a fresh solvent or the like every time one or more times of extraction. A batch-type contact method that can be replaced can be used. After a single tank is installed, carbon dioxide, lead-containing soft polyvinyl chloride material and an alcohol solvent are introduced into the tank, and the tank is brought to a supercritical state. You may make it contact, and you may provide the some tank, and may separate the tank made to contact with the tank which makes a carbon dioxide and alcoholic solvent a supercritical state.

  The conditions for bringing the lead-containing soft polyvinyl chloride material and the alcohol solvent into contact with each other under the supercritical state of carbon dioxide are adjusted to the conditions under which carbon dioxide becomes a supercritical state. Also, the conditions can be adjusted so as to be in a supercritical state. Conditions for carbon dioxide to be in a supercritical state may be adjusted to a temperature and pressure higher than the conditions of a temperature of about 31 ° C. and a pressure of about 7.3 MPa in the vicinity of the critical point. It is preferable that the pressure is adjusted to 7.3 MPa or more and 20 MPa or less at 70 ° C. or less.

  In the raw material recovery method of the present invention, as long as the object of the present invention can be achieved, it may be adjusted to the temperature and pressure in the vicinity thereof, even if it is not above the critical point of the carbon dioxide.

  The means for bringing the carbon dioxide into a supercritical state is not particularly limited as long as it is a heating and pressurizing means that enables the temperature and the pressure. For example, an electric heater or a heat medium can be used for the heating. In order to efficiently heat in a short time, it is preferable to use microwave heating means, for example, a high-frequency heating device. For pressurization, it is preferable to use a pressure-resistant airtight container, for example.

  While the lead-containing soft polyvinyl chloride material and the alcohol-based solvent are in contact with each other under the supercritical state of carbon dioxide, the system may be kept stationary, and the system may be moved by stirring means such as a stirring blade. The inside may be stirred. It is preferable to stir the system because the extraction efficiency of the plasticizer and the lead compound is increased.

  The time for bringing the lead-containing soft polyvinyl chloride material and the alcohol solvent into contact with each other under the supercritical state of carbon dioxide varies depending on the type of the alcohol solvent. It is preferably 2 hours or less.

  When adopting the batch contact method, measure the concentration of the plasticizer in the supercritical liquid component recovered for each batch, until the measured concentration falls below the detection limit. repeat. Examples of the means for measuring the plasticizer concentration include known compound identification methods and quantitative methods such as infrared absorption spectrum (IR), high performance liquid chromatograph (HPLC), and gel permeation chromatograph (GPC). Can do.

  In this way, when the lead-containing soft polyvinyl chloride material and the alcohol solvent are brought into contact with each other under the supercritical state of the carbon dioxide, the carbon dioxide in the supercritical state has high diffusibility and high solubility. Therefore, the plasticizer can be efficiently extracted from the lead-containing soft polyvinyl chloride material into carbon dioxide in a supercritical state.

A supercritical liquid component obtained by extracting a plasticizer into carbon dioxide in a supercritical state is separated from the solid. When the liquid component is released from the supercritical state, the plasticizer is separated. When the alcohol solvent is contained in the liquid component, a solution containing the alcohol solvent and the plasticizer is obtained by releasing the supercritical state. The plasticizer is recovered by removing the solvent from the solution. Thus, the plasticizer is recovered from the liquid component.
On the other hand, the solid material includes a soft polyvinyl chloride resin and a lead compound. However, when the alcoholic solvent is contained in the residue from which the liquid component has been removed, a solid-liquid residue containing the solid is obtained.

  Next, the solid-liquid residue is separated into solid and liquid components by solid-liquid separation means. The solid-liquid separation means is not particularly limited, and examples thereof include known means such as filtration means and centrifugal separation means. The solid matter separated by the solid-liquid separation means is a mixture containing a soft polyvinyl chloride resin and a lead compound.

  By mixing this mixture with a surfactant such as an anionic surfactant, the lead compound in the mixture can be extracted into the surfactant. In this extraction, the lead compound and the surfactant may react to produce a compound that is soluble in the surfactant, for example, a chelate compound, and in some cases, the lead compound may be eluted into the surfactant. is there. Thus, the mixture and the surfactant are mixed to be separated into a solid and a liquid. The separated solid is a polyvinyl chloride resin, and a lead-containing compound such as the chelate compound or the lead compound is recovered from the liquid.

  Next, a raw material recovery apparatus for lead-containing soft polyvinyl chloride material used in the raw material recovery method of the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic explanatory view showing a raw material recovery apparatus for a lead-containing soft polyvinyl chloride material as an example capable of carrying out the raw material recovery method of the present invention. The raw material recovery apparatus shown in FIG. 1 is an example of a batch type apparatus.

  As shown in FIG. 1, the raw material recovery apparatus 1 for lead-containing soft polyvinyl chloride material includes a tank 2.

  The tank 2 is made of pressure-resistant because it needs to bring carbon dioxide into a supercritical state, and is formed so as to be hermetically sealed. Further, the tank 2 is provided with a stirring device 2A, a heating device 2B, an alcohol solvent supply device 8, and a liquefied carbon dioxide supply device 9. The alcohol-based solvent supply device 8 includes an alcohol-based solvent storage tank 8A, and fluid transfer means 8B for connecting the storage tank 8A and the tank 2, for example, piping. A pump 8C that sucks and discharges the alcohol solvent in the storage tank 8A and a manual valve 8D are interposed between the storage tank 8A and the tank 2 in the fluid transfer means 8B. . The liquefied carbon dioxide supply device 9 includes a cylinder 9A filled with liquefied carbon dioxide, and a fluid transfer means 9B, for example, a pipe, that couples the cylinder 9A and the tank 2. A manual valve 9C is interposed between the cylinder 9A and the tank 2 in the fluid transfer means 9B.

  The tank 2 is provided with a filtration device 4, a detection device 10, and a surfactant supply device 11. The filtration device 4 includes a discharge pipe 5 provided at the bottom of the tank 2, a manual valve 5A interposed in the middle of the discharge pipe, a filter 4A installed downstream of the discharge pipe 5, A storage tank 4B for storing the filtrate separated by the filter 4A is provided. The detection device 10 includes, for example, an IR measuring device. The surfactant supply device 11 includes a surfactant storage tank 11 </ b> A, and a manual valve 11 </ b> B provided between the storage tank 11 </ b> A and the tank 2. Moreover, the said tank 2 and the said detection apparatus 10 are couple | bonded through the fluid transfer means 7, for example, piping. A back pressure valve 7A is interposed in the middle of the fluid transfer means 7, and carbon dioxide and alcohol solvent are discharged from the tank 2 to the detection device 10 by opening and closing the back pressure valve 7A. The detection device 10 is provided with a plasticizer-containing solvent storage tank 12 in addition to the fluid transfer means 7, and the plasticizer-containing solvent storage tank 12 is provided with an open valve (not shown).

  This lead-containing soft polyvinyl chloride material raw material recovery apparatus 1 operates as follows.

  First, the first plasticizer extraction operation is performed. The manual valve 5A is closed, and the crushed or crushed material of the lead-containing soft polyvinyl chloride material P is put into the tank 2. Next, the back pressure valve 7A and the manual valve 9C are opened, and the inside of the tank 2 and the fluid transfer means 7 are replaced with liquefied carbon dioxide.

  Subsequently, after the back pressure valve 7A is closed, the manual valve 8D and the manual valve 9C are opened, so that a predetermined amount of alcohol solvent and a predetermined amount of carbon dioxide are brought to a predetermined pressure. Until it becomes, it is supplied to the tank 2. When a predetermined amount of alcohol solvent and carbon dioxide are supplied to the tank 2, the manual valve 8D and the manual valve 9C are closed.

  Next, the stirring device 2A and the heating device 2B of the tank 2 are started, carbon dioxide is brought into a supercritical state, and the alcohol solvent and the carbon dioxide in the supercritical state are mixed with lead-containing soft polyvinyl chloride material P. To touch. The contact is performed for a predetermined time, and the plasticizer is extracted from the lead-containing soft polyvinyl chloride material P into carbon dioxide and an alcohol solvent in a supercritical state. Carbon dioxide and alcohol solvents in the supercritical state and the plasticizer extracted in these form a liquid component in the supercritical state.

  Next, the back pressure valve 7A is opened. Even if the back pressure valve 7A is opened, the pressure in the tank 2 is adjusted so that carbon dioxide maintains a supercritical state. The liquid component in the supercritical state derived from the back pressure valve 7A flows into the detection device 10. In the detection device 10, the type and content of the plasticizer contained in the liquid component are monitored. The monitored liquid component is stored in the plasticizer-containing solvent storage tank 12.

  Until the amount of the plasticizer detected by the detection device 10 reaches a predetermined amount or less or a detection limit amount or less, carbon dioxide in a supercritical state in the tank 2, an alcohol solvent, and a lead-containing soft polyvinyl chloride system The materials P are repeatedly brought into contact with each other.

  The alcohol solvent and carbon dioxide in a supercritical state are brought into contact with the lead-containing soft polyvinyl chloride material P for a predetermined time. Thereafter, the plasticizer is detected by the detection device 10, and all the liquid components in the tank 2 are transferred to the plasticizer-containing solvent storage tank 12. When the amount of the plasticizer does not reach the predetermined amount or below the detection limit amount, the batch operation of the plasticizer extraction is performed n times for the second time and the third time until the amount of the extracted plasticizer reaches the target amount. . The operation of extracting the plasticizer from the second time is the same as the first extraction operation.

  When the amount of the plasticizer detected by the detection device 10 reaches a predetermined amount or less or a detection limit or less, an opening valve (not shown) of the plasticizer-containing solvent storage tank 12 is opened. As a result, the supercritical state in the tank 2 and the plasticizer-containing solvent storage tank 12 is released, so that the carbon dioxide in the tank 2 and the plasticizer-containing solvent storage tank 12 becomes gaseous and is released outside the apparatus. The Moreover, a plasticizer can be collect | recovered if the alcohol-type solvent in the liquid component in the plasticizer containing solvent storage tank 12 is removed by distillation.

  The lead compound in the solid matter remaining in the tank 2 is extracted by the surfactant.

  Regarding the extraction operation of the lead compound, since the alcohol solvent and carbon dioxide are not necessary, the manual valve 8D and the manual valve 9C are closed and the liquid component in the tank 2 is removed.

  Extraction of the lead compound from the solid material is performed by opening the manual valve 11B, putting a predetermined amount of the surfactant in the storage tank 11A into the tank 2, and transferring the lead compound contained in the solid material into the surfactant. Do that. Thereby, when a lead compound is extracted in the tank 2, the lead compound is transferred to the surfactant as a lead chelate compound, which is a reaction product of the lead compound and / or the surfactant and the lead compound, and becomes a liquid component. Polyvinyl chloride remains as a solid content. Therefore, the inside of the tank 2 is in a solid-liquid separation state. Next, the manual valve 5A is opened, the contents in the tank 2 are supplied to the filter 4A through the discharge pipe 5 and separated into solid and liquid, the solid content remains on the filter 4A, and the liquid component is stored in the storage tank. Stored in 4B. A lead compound and / or a lead chelate compound can be recovered by removing the surfactant from the liquid component in the storage tank 4B by a known removal means or the like.

  As the surfactant, a cationic surfactant, an anionic surfactant, an amphoteric surfactant and / or a nonionic surfactant can be used. Of the surfactants, anionic surfactants and / or nonionic surfactants are preferably used. Examples of suitable anionic surfactants include fatty acid soaps, ether carboxylic acids and salts thereof, and higher fatty acids. Sulfonates such as condensates with amino acids, higher alkyl sulfonates, α-olefin sulfonates, higher fatty acid ester sulfonates, dialkyl sulfosuccinates, and higher fatty acid amide sulfonates Examples of suitable nonionic surfactants include, for example, single chain length polyoxyethylene ether type, polyoxyethylene alkyl and alkyl allyl ether type, and ethylene oxide of alkylphenol formalin condensate. Ether type nonionic surfactants such as derivatives , Polyoxyethylene ether type containing an ester bond, and ether ester type nonionic surfactants such as natural fats and waxes polyoxyethylene derivatives, polyoxyethylene fatty acid esters, and ester type nonions such as polyhydric alcohol esters Examples thereof include block surfactants such as block surfactants, pluronic types, tetronic types, and block polymer types containing an alkyl group, and nitrogen-containing nonionic surfactants. A commercially available surfactant can be used in the raw material recovery method of the present invention. Further, the surfactant used in the raw material recovery method of the present invention is particularly preferably an alkaline anionic surfactant and a nonionic surfactant used in admixture because the extraction efficiency is good.

  Another embodiment of the raw material recovery method of the present invention is shown in FIG.

  As shown in FIG. 2, the raw material recovery device 1 for lead-containing soft polyvinyl chloride-based material is different from the device 1 shown in FIG. 1 in that the second tank 3 is located upstream of the tank 2, And an on-off valve 6A. The apparatus 1 shown in FIG. 1 has one tank to be contacted, and every time the plasticizer is extracted, carbon dioxide and an alcohol solvent are injected into the tank 2 to bring the inside of the tank 2 into a supercritical state. 2 is provided, the apparatus 1 shown in FIG. 2 is provided with the second tank 3 to extract the plasticizer necessary for the next extraction in the second tank 3 while extracting the plasticizer in the tank 2. Since the carbon and alcohol solvent can be brought into a supercritical state, the time required for extraction of the plasticizer can be shortened.

  The tank 2 and the second tank 3 are brought into communication with each other by a fluid transfer means 6, and an opening / closing valve 6 </ b> A is interposed in the fluid transfer means 6.

  Since the supercritical carbon dioxide and the alcohol solvent are transferred to the second tank 3, the second tank 3 is made of a pressure-resistant product and can be sealed. The second tank 3 is provided with a stirring device 3A. The second tank 3 is coupled with a fluid transfer means 8B for supplying an alcohol solvent and a fluid transfer means 9B for supplying carbon dioxide.

  This lead-containing soft polyvinyl chloride material raw material recovery apparatus 1 operates as follows.

  First, the plasticizer extraction operation is performed as follows.

  The manual valve 5A is closed, and the crushed material P or crushed material P of the lead-containing soft polyvinyl chloride material is charged into the tank 2. Subsequently, the on-off valve 6A, the back pressure valve 7A and the manual valve 9C are opened, and the tank 2, the fluid transfer means 6, the second tank 3 and the fluid transfer means 7 are replaced with carbon dioxide.

  Next, the back pressure valve 7A is closed and the on-off valve 6A is opened, the manual valve 8D of the alcohol solvent supply device 8 is opened, and a predetermined amount of the alcohol solvent and carbon dioxide are supplied to the second. It is press-fitted into the tank 3 and the tank 2. Furthermore, the stirring devices 2A and 3A and the heating devices 2B and 3B are activated, and the alcohol solvent and carbon dioxide in the tank 2 and the second tank 3 are stirred and heated to a predetermined temperature. At least carbon dioxide is brought to a supercritical state. In the tank 2, the lead-containing soft polyvinyl chloride material P is in contact with carbon dioxide and alcohol solvent in a supercritical state.

  After contacting the lead-containing soft polyvinyl chloride material P with the supercritical carbon dioxide and alcohol solvent in the tank 2 for a certain period of time, the back pressure valve 7A is opened while the open / close valve 6A is open. To do. Thereby, the liquid component containing the alcohol solvent and carbon dioxide in the supercritical state is discharged from the tank 2 through the fluid transfer means 7, and the content of the plasticizer in the discharged liquid component is detected by the detection device 10. Detected by. The liquid component that has passed through the detection device 10 is stored in the plasticizer-containing solvent storage tank 12.

  By leaving the back pressure valve 7 and the on-off valve 6A open, the inside of the tank 2A is replaced with fresh carbon dioxide and an alcohol solvent. Completion of replacement can be confirmed by the detection device 10 when the plasticizer content falls below the detection limit.

  After the inside of the tank 2A is replaced with fresh carbon dioxide and an alcohol solvent, the back pressure valve 7A is closed, and the supercritical state in the plasticizer-containing solvent storage tank 12 is released to thereby remove the alcohol solvent and the plasticizer. To obtain a solution having The plasticizer is recovered from this solution.

  On the other hand, in the tank 2 replaced with fresh carbon dioxide and alcohol solvent, the plasticizer is further extracted with fresh carbon dioxide and alcohol solvent in a supercritical state. When the extraction operation is completed over a predetermined time, the back pressure valve 7A is opened again, and the liquid component in the supercritical state is transferred to the plasticizer-containing solvent storage tank 12 and stored.

  As described above, the supercritical carbon dioxide and alcohol solvent are continuously transferred from the second tank 3 to the tank 2 while the on-off valve 6A is opened, and the back pressure valve 7A is opened intermittently. Thus, the liquid component containing the carbon dioxide and alcohol solvent in a supercritical state in the tank 2 and the plasticizer extracted by these is transferred to the plasticizer-containing solvent storage tank 12 and stored.

  Each time the liquid component is intermittently transferred, the detection device 10 detects the plasticizer. When the detection device 10 determines that the plasticizer is no longer than the detection limit, the on-off valve 6A is closed and the back pressure valve 7A is turned on. The liquid component in the tank 2 is transferred to the plasticizer-containing solvent storage tank 12 to leave a solid content in the tank 2.

  The lead compound is extracted by the surfactant from the solid matter containing the polyvinyl chloride and the lead compound remaining in the tank 2.

  Extraction of the lead compound from the solid material is performed by opening the manual valve 11B, putting a predetermined amount of the surfactant in the storage tank 11A into the tank 2, and transferring the lead compound contained in the solid material into the surfactant. Do that. Thus, when the lead compound is extracted in the tank 2, the lead compound is transferred to the surfactant as a lead compound and / or as a lead chelate compound which is a reaction product of the surfactant and the lead compound, and is liquid. It becomes a component, and the polyvinyl chloride remains as a solid content. Therefore, the inside of the tank 2 is in a solid-liquid separation state. Next, the manual valve 5A is opened, the contents in the tank 2 are supplied to the filter 4A through the discharge pipe 5 and separated into solid and liquid, the solid content remains on the filter 4A, and the liquid component is stored in the storage tank. Stored in 4B. By removing the surfactant from the liquid component in the storage tank 4B, the lead compound and / or the lead chelate compound can be recovered.

  As described in detail, in the raw material recovery method of the present invention, since the lead-containing soft polyvinyl chloride material and the alcohol solvent are brought into contact with each other in the supercritical state of carbon dioxide, carbon dioxide in the supercritical state is brought into contact. With its high diffusivity and high solubility, it is possible to efficiently extract plasticizers from lead-containing soft polyvinyl chloride materials, and to remove polyvinyl chloride resin and lead compounds from solids remaining after plasticizer extraction. Can be separated. Therefore, according to this invention, it is possible to provide a raw material recovery method for a lead-containing soft polyvinyl chloride material capable of recovering a soft polyvinyl chloride resin, a plasticizer, and a lead compound from a lead-containing soft polyvinyl chloride material. it can.

  In addition, since the raw material recovery method of the present invention is not an incineration process, it does not generate dioxins, and since it is not a landfill process, there is no soil contamination and does not adversely affect the environment.

  The carbon dioxide used for extraction can be reused by attaching carbon dioxide recovery means to an open valve (not shown) provided in the plasticizer-containing solvent storage tank 12 of the apparatus 1 shown in FIGS. .

  Furthermore, in the raw material recovery method of the present invention, when the used alcoholic solvent is distilled off, the alcoholic solvent can be recovered and reused, so that the amount of waste is reduced as a whole, and the waste is treated. Cost increase and secondary environmental pollution can be prevented.

  The separated polyvinyl chloride can be reused as a raw material for soft polyvinyl chloride products.

  The following examples are experimental examples of the present invention.

Example 1
The apparatus shown in FIG. 1 was used. In a tank 2 made of SUS having an internal capacity of 1000 mL equipped with a heating device and a stirring device, 5 g of a sample obtained by pulverizing a lead-containing soft polyvinyl chloride resin composition to an appropriate size and 20 mL of methanol were charged. At this time, the back pressure valve 7A was closed.

  The sample contains 23 parts by mass of di-isononyl-phthalate (DINP) and 1.7 parts by mass of lead stearate with respect to 100 parts by mass of vinyl chloride for wire coating, according to information from the sample supplier. Was.

  Next, as a first operation, carbon dioxide gas was injected into the tank 2 while maintaining the internal temperature at 55 ° C., and the internal pressure was adjusted to 10 MPa. By stirring the inside of the tank 2, the inside of the tank 2 was brought into a supercritical state of carbon dioxide, and the lead-containing soft polyvinyl chloride sample, methanol and carbon dioxide were brought into contact with each other for 20 minutes.

  Subsequently, the back pressure valve 7A was opened, and the liquid component in the supercritical state in the tank 2 was transferred to the plasticizer-containing solvent storage tank 12 via the fluid transfer means 7. During the transfer, the detection device 10 inspects the presence or absence of the plasticizer contained in the liquid component. Since the plasticizer contained in the liquid component was detected by the detection device 10, it was determined that the next second operation was necessary.

  The second operation was performed as follows. First, the back pressure valve 7A was closed. 20 mL of methanol was newly supplied into the tank 2. Similarly to the first operation, carbon dioxide gas was injected into the tank 2 while maintaining the temperature in the tank 2 at 55 ° C. again, so that the internal pressure was 10 MPa. By stirring the inside of the tank 2, the inside of the tank 2 was brought into a supercritical state of carbon dioxide, and the sample, methanol, and carbon dioxide were brought into contact with each other for 20 minutes. Then, the liquid component which exists in the tank 2 was transferred to the plasticizer containing solvent storage tank 12 like the 1st operation.

  The same operation as the first and second operations was repeated 21 times thereafter. As a result, a solid was obtained in the tank 2. In the 23rd operation, DINP is detected in the liquid component transferred from the tank 2 to the plasticizer-containing solvent storage tank 12 via the fluid transfer means 7 according to the FT-IR which is the detection device 10. There wasn't. Since it was no longer detected, it was judged that the plasticizer was substantially completely extracted from the lead-containing soft polyvinyl chloride sample.

  The treated sample remaining in the tank 2 was subjected to the required treatment and then measured with a GC-MS apparatus to determine the content of the plasticizer remaining in the sample. As a result, 9.9 ppm of DINP was observed in the treated sample.

  Similarly, the recovered liquid component was subjected to a required treatment and then measured with a GC-MS apparatus to quantify DINP and hexanol present in the liquid portion. As a result, the DINP separation and recovery rate was 99%, and hexanol was not detected. As a result, it was confirmed that the raw material recovery method of the present invention can recover DINP with high purity. In addition, the fact that hexanol was not detected indicates that DINP was not decomposed while the sample was brought into contact with carbon dioxide and methanol in a supercritical state.

  In addition, a mixture of an anionic surfactant and a nonionic surfactant supplied from the surfactant supply device 11 to the solid matter remaining in the tank 2 (product name “White 7-L” manufactured by UI Chemical Co., Ltd.) In this case, the solid is separated into liquid and solid components, and the filtration device 4 collects polyvinyl chloride from the solids and contains a mixture of anionic surfactant and nonionic surfactant as liquid components. The lead compound was recovered from the washed washing liquid.

(Comparative Example 1)
A Teflon (registered trademark) beaker having an internal volume of 100 ml was charged with 0.5 g of a sample composed of a lead-containing soft polyvinyl chloride film and 50 ml of an alkaline aqueous solution prepared by dissolving 8M caustic soda in water.

  A Teflon (registered trademark) beaker containing a soft polyvinyl chloride film and an alkaline aqueous solution is placed in a high-frequency heating device (microwave heating device), and the contents of the beaker are 150 by irradiating high-frequency waves. Heated to a predetermined temperature of 30 ° C. for 30 minutes.

  After heating for a predetermined time, the beaker was taken out from the high-frequency heating apparatus, and the soft polyvinyl chloride sample was washed with water to remove caustic soda.

  The content of DINP in the soft polyvinyl chloride film after the heat treatment was measured with an ion chromatograph apparatus. DINP remaining in the soft polyvinyl chloride film after the treatment was 22 pm, and 205 ppm of hexanol was contained in the alkaline aqueous solution. The fact that hexanol was contained in the alkaline aqueous solution indicates that DINP was decomposed during the heat treatment.

FIG. 1 is a schematic explanatory view showing a raw material recovery apparatus for a lead-containing soft polyvinyl chloride material as an example capable of carrying out the raw material recovery method of the present invention. FIG. 2 is a schematic explanatory view showing a raw material recovery apparatus for a lead-containing soft polyvinyl chloride material as another example capable of carrying out the raw material recovery method of the present invention.

Explanation of symbols

1 Raw material recovery device for lead-containing soft polyvinyl chloride material 2 Tank 2A, 3A Stirrer 2B, 3B Heating device 3 Second tank 4 Filtration device 4A Filter 4B Reservoir 5 Discharge pipe 5A, 6A, 8D, 9C, 11B Manual valve 6 Fluid transfer means 7, 8B, 9B Fluid transfer means 7A Back pressure valve 8 Alcohol solvent supply device 8A, 11A Reservoir 8C Pump 9 Liquefied carbon dioxide supply device 9A Cylinder 10 Detection device 11 Surfactant supply device 12 Plastic Agent-containing solvent storage tank P Lead-containing soft polyvinyl chloride material

Claims (1)

And lead-containing soft polyvinyl chloride le Material, the lead-containing soft poly and carbon dioxide in a supercritical state above 100 parts by weight with respect to the vinyl chloride material 100 parts by mass, the lead-containing soft polyvinyl chloride material 100 parts by weight The solid obtained by contacting 20 to 100 parts by mass with an aliphatic alcohol having 1 to 3 carbon atoms , recovering the plasticizer from the liquid component in the supercritical state, and releasing the supercritical state raw material recovery method of a lead-containing soft polyvinyl chloride le-containing material and recovering a lead compound by adding a surfactant to the object.

Images