JP4325542B2 - Polymer compound treatment method and apparatus - Google Patents

Description

  TECHNICAL FIELD The present invention relates to a processing method and apparatus for a polymer compound which is a thermoplastic resin or wax obtained by modifying a polymer compound into a modification reaction, a decomposition reaction, a crosslinking point or a molecular chain of a crosslinked polymer, and an extruder for supplying a material. The present invention relates to a method and apparatus for treating a polymer compound in which a polymer compound is reacted with a supercritical drug.

  In recent years, waste disposal costs are increasing year by year as environmental issues become important. The momentum of recycling and recycling is also increasing for polymers. In such a movement, material recycling is progressing because thermoplastic resin can be molded again with increased fluidity when heated. However, on the other hand, thermosetting resins, cross-linked polymers, elastomers, and the like are difficult to recycle materials because they are not fluidized due to the three-dimensional network of molecules and cannot be molded even when heated. For this reason, except for some thermal recycling, in many cases, it is disposed of by landfill or the like.

  Regarding such thermosetting resins and cross-linked polymers, the movement to carry out material recycling has increased, and various studies have been reported. For example, the three-dimensional network structure in the molecule is destroyed to make it thermoplastic, and this can be reused, or it can be waxed by cutting the polymer main chain to make it low molecular, and this can be added to resins, building materials, etc. It is considered to be reused as an agent.

  In order to make such an approach practical, a process for continuously processing the polymer is essential, and the use of an extruder is suitable for this. Heat and pressure are required to break down the three-dimensional network in the molecule of a stable thermosetting resin or cross-linked polymer, and heat and pressure are required. Obtainable. The same applies to waxing. In the case of thermoplasticizing, a thermoplastic resin or a chemical is often added together with a thermosetting resin or a crosslinked polymer, but such an additive can be easily introduced by using an extruder.

  For example, in Patent Document 1, crosslinked polyethylene and water are supplied to a material supply extruder, and water is supercritical or subcritical in the material supply extruder, that is, a temperature of 200 to 1000 ° C. and a pressure of 2 to 100 MPa. Shows a method of extruding to a thermoplastic material.

  In Patent Document 2, a cross-linked polymer is extruded from a material supply extruder and introduced into a reactor together with a high-temperature and high-pressure fluid to produce a reactant, and the reactant is introduced into a separator to separate the reactant into a high-temperature fluid. It is shown that the reaction product is discharged to the outside by a degassing extruder.

JP 2001-253967 A Japanese Patent Laid-Open No. 2002-249618

  In Patent Document 1, water acts as an agent for thermoplasticizing a thermosetting resin or a crosslinked polymer by a chemical reaction. On the other hand, in patent document 2, in order to isolate | separate them after mixing a reactive agent and a thermosetting resin, the separation tank for isolate | separating the mixture of a polymer and gas is provided, and in order to maintain a high-pressure state, A pressure regulating valve is used upstream.

  In these conventional examples, although a high pressure is held by an extruder, there is no effective means for countermeasures when such high-pressure water, gas, chemicals, etc. flow backward to the hopper side of the extruder. Therefore, there is a problem in industrially processing a large amount of polymer.

  In examining the practical application of the device of Patent Document 2, we have found that depending on the conditions, gas may flow backward to the upstream side of the material supply extruder and may be ejected from the hopper.

  The object of the present invention is to inject gas into the material supply extruder while extruding a polymer compound using the material supply extruder, when the gas flows back to the hopper upstream of the material supply extruder. The mixture of the polymer compound and the drug into a high-temperature and high-pressure container while kneading the polymer compound and the drug in the material supply extruder while preventing the gas from diffusing around. It is to provide a method and an apparatus for producing a polymer processed product by discharging and reacting.

  In view of the above-described problems, the present invention provides a mixture of a reaction agent and a resin in a material supply extruder, and even when the drug gas flows back to the hopper on the upstream side of the material supply extruder, The present invention has been made by examining various techniques for realizing a device capable of preventing gas from being diffused.

According to the first aspect of the present invention, a polymer compound is charged from a hopper into a material supply extruder, and a drug is injected into the material supply extruder while the polymer compound is being extruded. In a method of producing a polymer processed product by discharging the mixture of the polymer compound and the drug into a high-temperature and high-pressure high-pressure vessel while kneading in the material supply extruder Attach a drug diffusion prevention box for preventing the diffusion of the drug flowing back from the material supply extruder to the hopper of the material supply extruder, and supply the drug gas flowing back from the material supply extruder to the drug diffusion prevention box A method for treating a polymer compound, wherein a trap is connected via an open / close valve, and local exhaust is performed by a local exhaust apparatus in which a vacuum pump is connected to the trap .

The invention of claim 2 comprises a hopper for charging a polymer compound,
A material supply extruder for kneading the polymer compound and the polymer compound injected in the middle while extruding the polymer compound charged from the hopper;
In an apparatus for treating a polymer compound comprising a high-pressure vessel for producing a polymer-treated product by reacting the mixture of the polymer compound discharged from the material supply extruder and the drug at a high temperature and a high pressure,
Attach a drug diffusion prevention box for preventing diffusion of the drug flowing back from the material supply extruder to the hopper of the material supply extruder, and a trap is connected to the drug diffusion prevention box via an open / close valve, The polymer compound processing apparatus is characterized in that a vacuum pump is connected to the trap, and a local exhaust device for discharging the chemical gas flowing backward from the material supply extruder is connected.

The invention of claim 3 is for degassing for separating the reaction product of the polymer processed product and the drug from the high-pressure vessel connected to the material supply extruder into the polymer processed product and the drug. An extruder,
Pressure adjusting means for introducing the reaction product of the polymer-treated product and the chemical from the high-pressure vessel into the degassing extruder in a state where the pressure is lower than the pressure of the high-pressure vessel;
In order to introduce the chemical separated from the reaction product in the degassing extruder, connected to the introduction portion of the degassing extruder on the side opposite to the discharge portion of the degassing extruder Vent box and
3. The apparatus for treating a polymer compound according to claim 2, wherein the separated polymer processed product is extruded by the degassing extruder and the separated drug is exhausted from the vent box through a trap and a vacuum pump. It is.

The invention according to claim 4 is the polymer compound processing apparatus according to claim 3 , wherein the trap connected to the vent box is connected to the drug diffusion prevention box.

In the invention of claim 5 , a gas sensor is attached to the drug diffusion prevention box of the material supply extruder, and when the drug flows back into the drug diffusion prevention box, the drug diffusion prevention box and trap automatically. The apparatus for treating a polymer compound according to any one of claims 2 to 4 , wherein a valve in between is opened.

  The present invention preferably further includes the following features.

  It has an impurity separation process for separating impurities from the drug after separating the drug by a degassing extruder, and a drug storage process for storing the drug from which the impurities have been separated and introducing the drug into the material supply extruder. preferable.

  In order to separate the drug by the degassing extruder, the degassing extruder preferably has a vent mechanism.

  In order to separate the drug by the degassing extruder, it is preferable that the vent mechanism of the degassing extruder is connected to a vacuum pump through a trap.

  The trap to which the vent mechanism is connected is preferably connected to the drug diffusion prevention box.

  It is preferable to have a cooling step for cooling the polymer-treated product and a cutting step for cutting the cooled polymer-treated product.

  The reaction is, for example, any one of a modification reaction, a decomposition reaction, and a cross-linking cleavage reaction.

  The polymer compound is preferably a crosslinked polymer, and the drug is preferably an alcohol or a mixture containing alcohols.

  It is preferable to mix and stir the polymer compound pulverized inside the material supply extruder and the agent to be reacted with the polymer compound at high temperature and high pressure.

  A gas sensor is attached to the drug diffusion prevention box of the material supply extruder so that when the drug flows back into the drug diffusion prevention box, the valve between the drug diffusion prevention box and the trap automatically opens. It is preferable to do.

  As described above, while extruding the polymer compound using the material supply extruder, the drug is injected into the cylinder of the material supply extruder, and the polymer compound and the drug are injected into the cylinder of the material supply extruder. In the method of producing a polymer-treated product by discharging and reacting the mixture of the polymer compound and the drug into a high-temperature and high-pressure high-pressure vessel while kneading in, injecting with a screw into the high-pressure vessel during normal operation The backflow of gas is prevented by the resin that is used. Therefore, there is a problem that when the supply of the material stops or the supply amount varies, the gas flows backward and is ejected from the hopper.

  On the other hand, if a drug diffusion prevention box is attached, a polymer-processed product can be obtained without diffusing gas even when the drug gas flows backward to the hopper located upstream of the material supply extruder. Is possible.

  If the drug diffusion prevention box is not equipped with a mechanism for discharging the drug gas that has flowed back to the inside, there is a possibility that gas will stay in the drug diffusion prevention box or overflow from the drug diffusion prevention box. . In the case of combustible gas, there is a problem of igniting, so a local exhaust device is attached.

  In addition, if the drug diffusion prevention box is connected to the trap of the vacuum pump via a valve and the gas flows backward, the gas can be collected by opening this valve. Are more preferable because they can be recovered and reused.

  It is desirable that the drug diffusion prevention box is attached so as to surround the shooter generally attached to the hopper portion of the extruder so that the gas which seems to overflow from the shooter in the case of backflow does not diffuse around.

  Moreover, it is desirable that the trap size Vt of the vacuum pump to which the drug diffusion prevention box is connected is at least as large as the size V of the high-pressure vessel. More preferably, if Vt = P × V from the pressure P (atm), it is possible to collect the backflowed gas more reliably.

  Also, it is better to attach a filter to the entrance of the local exhaust fan to which the drug diffusion prevention box is connected so as not to suck the powder of the polymer material that may be ejected at the same time as the gas is ejected. .

  In the case where a polymer-treated product and a drug are introduced into a degassing extruder, the polymer-treated product and the drug are separated, and the separated polymer-treated product is molded by a degassing extruder, the drug diffusion If the prevention box and the vent mechanism of the degassing extruder are connected to the same trap, the trap and the vacuum pump can be used for two purposes.

  The polymer compound referred to in the present invention is a cross-linked polymer, a synthetic polymer of a thermosetting resin such as a plastic or an elastomer, a natural polymer such as lignin, cellulose, or protein, and a synthetic polymer and a natural polymer. Contains a mixture. Further, a material mainly composed of a polymer, such as shredder dust, mixed with other materials may be used.

  In particular, when a cross-linked polymer is used as the polymer compound and an alcohol or a mixture containing alcohol is used as the drug, such a device configuration functions effectively. In addition, such an apparatus configuration is particularly effective when chemically treating a polymer compound continuously in a high pressure state such as a supercritical condition in order to facilitate a reaction by a drug.

  While extruding the polymer compound using the material supply extruder, the drug is injected into the cylinder of the material supply extruder, and the polymer compound and the drug are kneaded in the cylinder of the material supply extruder. However, in the method of generating a polymer processed product by discharging the polymer compound and the drug mixture into a high-temperature and high-pressure high-pressure vessel and reacting them, the hopper of the material supply extruder also served as a local exhaust device If a drug diffusion prevention box is attached, it will be possible to prevent gas from diffusing to the surroundings even when high-pressure water, gas, chemicals, etc., flow backward to the hopper side of the extruder, and the polymer processed product can be safely removed. A method and apparatus for generating can be provided.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

  FIG. 1 is a flowchart showing an embodiment of a method and apparatus for treating a polymer compound of the present invention, and particularly showing an example of a crosslinking and cutting treatment of a crosslinked polyethylene as a polymer compound.

  The cross-linked polyethylene pulverized into pellets is fed into the material supply extruder 1 through a hopper 13.

  A drug diffusion prevention box 21 is attached to the hopper 13, and a local exhaust fan 22 is attached to the box 21. When a small amount of gas constantly flows backward, the fan 22 exhausts the gas. Further, the trap 16 and the vacuum pump 19 are connected via the valve 23, and when a large amount of gas flows backward at once, the valve 23 is opened and the gas is collected in the trap 16 together with the polymer. The valve 23 includes a mechanism 25 that is automatically opened when alcohol is detected by a gas sensor 24 attached to the hopper 13.

  The material supply extruder uses 30 mm L / D = 66. On the other hand, ethanol required for the reaction passes through the drug tank valve 17 from the drug tank 18 and is pressurized by the drug injection pump 15 and heated by the drug heater 14 and injected into the material supply extruder 1 at a pressure of 5 MPa. The The injection position is downstream of the position where the cross-linked polyethylene is pressurized to 1 MPa or higher in the material supply extruder 1 and densified, and the length of the pressure part is L / D = 5 or more. , Thereby preventing upstream leakage due to vaporization of the drug. As the material supply extruder 1, a biaxial extruder was used in order to feed cross-linked polyethylene which is difficult to be discharged. The drug injection pump 15 needs to be pressurized to a pressure higher than the internal pressure of the material supply extruder 1, and the drug heater 14 lowers the temperature of the polymer compound heated by the material supply extruder 1. It is desirable to raise the temperature to the extent that

In the material supply extruder 1, the charged cross-linked polyethylene and the injected chemical are mixed and stirred by a screw. At this time, if at least a part of the material supply extruder 1 is set to a temperature and pressure conditions at which ethanol as a drug is in a supercritical state, the cross-linking polyethylene reaction sufficiently proceeds, and a good polymer treatment is achieved. Things are obtained. Here, in order to ensure sufficient reaction time, a flow reaction vessel 100 having a volume of 50 L was connected to the extruder 1 as a high-pressure vessel .

  The mixture of the polymerized product of crosslinked polyethylene plasticized with the material supply extruder 1 and the flow-type reaction vessel 100 and the ethanol as a medicine is reduced in pressure by the pressure reducing valve 11, and a plurality of steps are used to lower the pressure stepwise. A breaker plate 31 is attached as a resistor having a hole in order to decompress the resin stepwise. Further, a degassing extruder 2 is connected to the subsequent stage. Here, the viscous liquid polymer processed product is extruded by a screw in the discharge direction of the extruder 2, and the gas is a back vent vent box 8 having a low pressure. The polymer processed product and the drug are separated by flowing into The vent box 8 is heated by a heater 10 that is an electric heater, and the polymer processed product is maintained at a temperature at which the polymer processed product exhibits fluidity. The inside of the vent box 8 is maintained at a pressure slightly higher than the normal pressure and lower than that of the reaction vessel 100, whereby the polymer processed product is easily discharged out of the vent box 8.

  In the vent box 8, the light gas is separated from the upper part of the tank, and even when the polymer processed material flows backward, the polymer processed substance is accumulated under the tank, and the degassing extrusion is carried out by its own weight from the hole provided in the lower part of the tank. It is sent to the machine 2 and molded by the die 3 at the tip. The degassing extruder 2 can be a single-screw or twin-screw extruder. Here, it is formed as a thread-like strand 5, and is cooled and solidified to substantially normal temperature by the cooler 4. The strand 5 becomes a pellet 7 by the strand cutter 6.

  The molding extruder 2 is provided with a vent 9 in order to completely remove the drug from the resin. Here, the pipe from the vent 9 is connected to the vacuum pump 19 via the adjustment valve 91, but may be connected to the trap 16, for example.

  On the other hand, ethanol, which is a drug separated from the polymer-treated product in the vent box 8, becomes normal pressure via the tank pressure adjusting valve 12 and is sent to the trap 16. In the trap 16, impurities such as polyethylene mixed in ethanol are separated by a filter, and at the same time, fractionated using the difference in boiling points. Ethanol is returned to the chemical tank 18, and impurities are sucked by the vacuum pump 19 and incinerated by the combustion device 20.

  Such an apparatus configuration is particularly effective in the case where the vaporized chemical flows backward to the upstream side when performing the process of mixing the polymer compound and the gaseous chemical at a high temperature and high pressure in an extruder in a high temperature and high pressure state. . When there is no gas diffusion prevention mechanism when backflowing as in Patent Documents 1 and 2, if the resin supply becomes unstable, etc., and the sealing with the polymer treatment product becomes insufficient, it leaked into the hopper There is a problem because high temperature gas or resin is blown around the hopper and diffuses around.

  On the other hand, if a drug diffusion prevention box is attached and the gas is exhausted or collected, high temperature gas or resin is not diffused around and can be operated safely.

  In the polymer processed product thus obtained, when the polymer processed product in the molten state and the gaseous chemical agent are not continuously released via the pressure reducing valve 11, but the gas is discharged intermittently, In order to expand, the polymer processed material which is a liquid is entrained and ejected vigorously. In this case, since the volume of the vent box 8 is sufficiently large, a buffering action is exerted against a change in pressure, and pressure fluctuation in the resin discharge direction is suppressed. Thus, even when the gas flows backward to the hopper 13 side, it is possible to continuously and smoothly form a polymer processed product by a safe method.

  Here, alcohol was injected at 5 MPa. When the supply amount of the raw material exceeds 50% with respect to the injection amount of alcohol, a mist of alcohol is generated in the hopper 13 located upstream from the injection position and backflowed. Did not spread. Furthermore, as a result of continuing the operation by reducing the supply amount of the raw material, a large amount of alcohol spouted from the hopper 13 side. However, when the valve 23 is opened, the alcohol and the polymer processed product can be recovered in the trap 16. It was possible to drive without splashing hot alcohol around.

  FIG. 2 shows another embodiment of the present invention.

  In the present embodiment, as shown in FIG. 2, a valve 11a is introduced between the material supply extruder 1 in FIG. 1 and the high-pressure vessel 100 composed of a flow-type reaction tube.

  As a result of the operation in the same manner as in the embodiment of FIG. 1, by closing this valve 11a when alcohol mist is generated, it is possible to prevent all the alcohol in the high-pressure vessel 100 from being ejected to the hopper 13 and to make it safer. It becomes possible to drive.

  FIG. 3 is a flowchart showing a cross-linked polyethylene cross-linking treatment apparatus as a comparative example of the present invention.

  In this comparative example, an apparatus without the drug diffusion preventing box in the embodiment of FIG. 1 was used.

  In the case of using this apparatus, when alcohol was injected at 5 MPa, alcohol mist was generated in the hopper 13 located upstream from the injection position, and the alcohol flowed back. As a result of continuing the operation, a large amount of alcohol spouted from the hopper 13 side, and the alcohol was scattered up to about 10 m in the periphery, so that the continuous operation could not be continued.

1 is a system diagram showing one embodiment of a polymer compound treatment apparatus of the present invention. FIG. It is a system diagram which shows other embodiment of this invention. It is a system diagram which shows the whole structure of the processing apparatus of the high molecular compound as a comparative example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Material supply extruder 2 Deaeration extruder 3 Die 4 Cooler 5 Strand 6 Strand cutter 7 Pellet 8 Vent box 9 Vent 10 Vent box heater 11 Depressurization valve 12 Tank pressure adjustment valve 13 Raw material hopper 14 Chemical heating heater 15 Chemical Pressure pump 16 Trap 17 Drug tank valve 18 Drug tank 19 Vacuum pump 20 Combustion device 31 Breaker plate 100 Flow-type reaction vessel

Claims (5)

A polymer compound is fed from a hopper into a material supply extruder, and while the polymer compound is being extruded, a chemical is injected into the material supply extruder, and the polymer compound and the drug are injected into the material supply extruder. In a method of producing a polymer processed product by discharging the mixture of the polymer compound and the drug into a high-temperature and high-pressure high-pressure vessel while kneading in A drug diffusion prevention box is installed to prevent the diffusion of the drug that has flowed back from the material supply extruder, and the gas of the drug flowing back from the material supply extruder is trapped in the drug diffusion prevention box via an open / close valve. A method for treating a polymer compound, characterized in that a local exhaust is performed by a local exhaust apparatus that is connected and a vacuum pump is connected to the trap . A hopper for charging the polymer compound;
A material supply extruder for kneading the polymer compound and the polymer compound injected in the middle while extruding the polymer compound charged from the hopper;
In an apparatus for treating a polymer compound comprising a high-pressure vessel for producing a polymer-treated product by reacting the mixture of the polymer compound discharged from the material supply extruder and the drug at a high temperature and a high pressure,
Attach a drug diffusion prevention box for preventing diffusion of the drug flowing back from the material supply extruder to the hopper of the material supply extruder, and a trap is connected to the drug diffusion prevention box via an open / close valve, A polymer compound processing apparatus , wherein a vacuum pump is connected to the trap, and a local exhaust device for discharging a drug gas flowing backward from the material supply extruder is connected. A degassing extruder for separating the reaction product of the polymer-treated product and the drug from the high-pressure vessel connected to the material supply extruder into the polymer-treated product and the drug;
Pressure adjusting means for introducing the reaction product of the polymer-treated product and the chemical from the high-pressure vessel into the degassing extruder in a state where the pressure is lower than the pressure of the high-pressure vessel;
In order to introduce the chemical separated from the reaction product in the degassing extruder, connected to the introduction portion of the degassing extruder on the side opposite to the discharge portion of the degassing extruder Vent box and
3. The apparatus for treating a polymer compound according to claim 2, wherein the separated polymer processed product is extruded by the degassing extruder and the separated drug is exhausted from the vent box through a trap and a vacuum pump. . The polymer compound processing apparatus according to claim 3 , wherein the trap connected to the vent box is connected to the drug diffusion prevention box. A gas sensor is attached to the drug diffusion prevention box of the material supply extruder so that when the drug flows back into the drug diffusion prevention box, the valve between the drug diffusion prevention box and the trap automatically opens. processor of the polymer compound according to any one of claims 2-4 that.

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