JP2003164819A - Method for cleaning extruder or its part - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for cleaning an extruder and its parts, by which a resin stuck to the part of the extruder is removed without damaging the part. <P>SOLUTION: A liquid solvent 10 is injected into an airtight vessel 1 which is connected to a pressurizing pump 3, disposed in a thermostatic bath 2. The part 20 of the extruder to which the residual resin A is stuck is placed in the vessel 1. The vessel 1 is shut tightly and the pump 3 and the bath 2 are started. The inside of the vessel 1 is kept under the conditions equal to or higher than the supercritical temperature and supercritical pressure of the solvent 10 so that the solvent 10 is transformed into a supercritical fluid by phase transition, namely, the inside of the vessel 1 is kept in the atmosphere of the supercritical fluid. The part 20 is brought into contact with the supercritical fluid so that the residual resin stuck to the part 20 is decomposed and the decomposed component is diffused in the supercritical fluid. After that, the temperature and pressure inside the vessel 1 are lowered so that the decomposed component-diffused supercritical fluid is transformed into the liquid by phase transition and the decomposed component-containing solvent 10 is retained at the bottom of the vessel 1. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for cleaning an extruder or parts thereof.

[0002]

2. Description of the Related Art As an extruder used for molding a resin such as plastic, there is known an extruder provided with a component having a complicated structure (for example, a breaker plate, a cross head, a die, etc.). FIG. 5 shows an extruder 100 for coating a resin layer on the outer circumference of the conductor. The resin material supplied from the hopper 101 is caused to flow in the cylinder 103 while being agitated by the rotation of the screw 102, and the heater 104 is also provided. The inside of the cylinder 103 is heated by the above to soften and dissolve the resin material, and the molten resin from which impurities are removed by the breaker plate 105 provided at the inlet of the head 106 is supplied to the running conductor at a right angle (cross head 106 ), The surface of the resin layer coated on the outer periphery of the conductor is processed by the die 107 at the tip of the head.

When the above-mentioned extruder 100 is repeatedly used, it is necessary to remove the residual resin A attached to the parts of the extruder (for example, the breaker plate 105, the crosshead 106, the die 107, etc.) and clean the parts. Becomes If the parts are not cleaned, the resin material used last time (residual resin A) adheres to the parts, causing defective products.

As a conventional cleaning method, after using an extruder, a cleaning resin containing a styrene resin, a silicone resin, and a fluororesin is flowed into the extruder, and a resin flow path in the extruder, particularly in the cylinder 103. Residual resin A attached to
In addition to removing the parts, a metal brush or the like is used for cleaning the parts having a complicated structure of the extruder (for example, the breaker plate 105, the crosshead 106, the die 107, etc.), and after removing each part from the extruder. ,
The residual resin A adhering to the details of each part was removed by rubbing the metal brush.

[0005]

However, when the conventional cleaning method, that is, when the parts are cleaned using the metal brush, it is difficult to remove the residual resin A adhering to the details of the parts, and even after the cleaning. There are problems that the residual resin A cannot be completely removed, that the surface of the component is finely scratched by frictional cleaning of the metal brush, and that the surface coating is peeled off.

[0006]

Therefore, in the method of cleaning the extruder or parts thereof according to the present invention, when removing the residual resin A adhering to the parts, fine scratches are formed on the surface of the parts or the coating on the surface is peeled off. The residual resin adhering to the parts of the extruder is decomposed by contacting it with the supercritical fluid and diffusing the decomposed components into the supercritical fluid atmosphere. Residual resin is removed.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment according to the present invention will be described with reference to the drawings.

In the method of cleaning the extruder and its parts according to the present invention, the residual resin A adhering to the parts 20 of the extruder and the resin flow path 21 of the extruder is decomposed and diffused using the supercritical fluid 10 '. It is to be removed and cleaned.

1 to 3 show a preferred embodiment of the present invention, which has a complicated structure and parts of an extruder (eg, breaker plate 105, cloth, etc.) which are difficult to clean the details. A method for cleaning the head 106, the die 107, etc. will be described. In this example, a part 20 having residual resin A adhered from the extruder used
(For example, breaker plate 105, cross head 0
16, the die 107, etc.) are removed, and the residual resin A
The residual resin A adhering to the parts 20 is decomposed and diffused by the supercritical fluid 10 'to remove the parts 20 by adhering the parts 20 having adhered thereto to the container 1 filled with the supercritical fluid 10'. It is something to clean.

FIG. 1 shows a container 1 in which a component to be cleaned (a component to which residual resin A is attached) 20 is provided. The container 1 is filled with a supercritical fluid 10 '. The container 1 can be hermetically sealed, is installed in a constant temperature bath 2, and a pressurizing pump 3 is connected to the container 1 to operate the constant temperature bath 2 to adjust the temperature in the container 1. ,
The pressure pump 3 is operated to adjust the pressure in the container 1. The container 1 is made of stainless steel having excellent corrosion resistance, durability, heat resistance, and rigidity (pressure resistance). Further, a thermometer 4 and a pressure gauge 5 for monitoring the temperature and pressure inside the container 1 are provided so that the temperature and pressure inside the container 1 can be adjusted and set to predetermined values.

Further, in the embodiment shown in FIG. 1, a container 1 provided with a lid 11 is used, the lid 11 is opened to put a component 20 in the container 1, and the opening is closed by the lid 11 to close the container. 1 can be sealed. Further, a placement table 6 is provided in the container 1, and the component 20 is placed on the placement table 6 so that the component 20 does not come into contact with the liquid solvent 10 injected into the bottom of the container 1. It can be placed. In this example, the liquid solvent 10
As a result, water (H ₂ O) is injected into the container 1.

FIG. 2 shows that after the component 20 having the residual resin A attached thereto is placed in the container 1 in which water (H ₂ O) 10 is injected, the lid 11 of the container 1 is closed to seal the container 1. In addition, a constant temperature bath 2 for accommodating the closed container 1 therein,
By operating the pressure pump 3 connected to the closed container 1 and maintaining the inside of the container 1 at a critical temperature (Tc) / critical pressure (Pc) or more, water (H ₂ O) in the container 1 Shows a state in which the container 1 is filled with supercritical water (supercritical fluid) 10 '.

In this embodiment, the constant temperature bath 2 and the pressure pump 3
To operate the inside of the container 1 at a temperature of 400 ° C. and a pressure of 250 kg.
By setting / maintaining f / m ² and changing the state of the water (H ₂ O) in the container 1, the supercritical water (supercritical fluid) 10 in the container 1 is changed.
Fill with ´.

In the container 1, the part 20 to which the residual resin A is attached is exposed to a supercritical water (supercritical fluid) atmosphere,
The entire part comes into contact with supercritical water (supercritical fluid). That is, the supercritical water (supercritical fluid) uniformly contacts the details of the component 20. Such supercritical water (supercritical fluid) 10 '
Residual resin A adhering to the component 20 due to contact with
Is decomposed, and the decomposed component A ′ is diffused into the atmosphere of supercritical water (supercritical fluid) 10 ′, and the residual resin A attached to the component 20 is removed.

In the embodiment shown in FIG. 2, the constant temperature tank 2 and the pressure pump 3 are operated to maintain the inside of the container 1 at a critical temperature (Tc) / critical pressure (Pc) or higher for 20 minutes, so that the residual resin A The attached component 20 is placed in a supercritical water (supercritical fluid) atmosphere 10 '.
20 minutes and exposed to this supercritical water (supercritical water) for 20 minutes to remove the residual resin A adhering to the component 20 and clean the component.

Then, the residual resin A adhering to the component 20 is completely decomposed by the supercritical water (supercritical fluid) filled in the container 1 (that is, the residual resin A adhered to the details is also decomposed uniformly. Then, after the decomposition component A ′ is diffused into the supercritical water atmosphere 10 ′, the critical temperature (T
c) -By lowering the temperature and pressure in the container 1 set to a critical pressure (Pc) or higher and returning to normal temperature / normal pressure, the supercritical water (supercritical fluid) in which the decomposition component A'is diffused is removed. The state is changed to a liquid, and the water (liquid solvent) 10 containing the decomposition component A ′ is retained at the bottom of the container. (See Figure 3)

Since the component 20 from which the residual resin A attached has been removed is placed on the placement table 6, the sewage (the liquid solvent 10 containing the decomposed component A ') remaining at the bottom is placed.
There is no risk of being contaminated by.

Further, the lid 11 of the container 1 is opened to take out the component 20 (the component from which the residual resin A attached has been removed) 20 placed in the container, and the sewage remaining at the bottom of the container 1 By discharging (the liquid solvent 10 containing the decomposition component A ′), the container 1 is repeatedly used, and the component 2
It can be used for zero cleaning work.

Table 1 shows a conventional cleaning method for the die and breaker plate which are parts of the extruder, that is, a case where the parts are cleaned using a metal brush (comparative example), and a cleaning method according to the present invention, that is, a container. The time required for cleaning work, the adhesion of residual resin after cleaning, surface scratches, and coating peeling were compared for the case where the parts were cleaned by contacting with supercritical water filled inside (Example). It is a thing.

[0020]

[Table 1]

As shown in Table 1, the conventional cleaning method, that is, the removed parts (die and breaker plate) are friction-cleaned with a metal brush and then with a solvent to remove the residual resin adhering to the parts. If removed,
Even after cleaning for 60 minutes, the residual resin that adhered to the details of each part could not be completely removed, and the adhesion of the residual resin was confirmed even after cleaning, and the friction of the metal brush rubbed the surface of the part. Scratches and coating peeling were confirmed.

On the other hand, like the cleaning method according to the present invention, the removed parts (die and breaker plate)
In a method of filling supercritical water in a container accommodating the above and contacting the supercritical water to decompose and disperse and remove the residual resin adhering to the parts, it takes 3 minutes of the cleaning time in the conventional cleaning method. By treating with supercritical water for 1 hour, that is, for 20 minutes, the residual resin A attached to each component is evenly removed over the details of the component, and after cleaning, the adhesion of the residual resin to the component is not confirmed, and the surface There were no scratches or coating peeling.

Therefore, according to the cleaning method of this embodiment, the inside of the closed container 1 containing the component 20 to which the residual resin A is adhered and filled with the liquid solvent 10 has a critical temperature (Tc).
By maintaining the critical pressure (Pc) or higher, the container 1
The state of the liquid solvent 10 injected into the inside is changed to fill the inside of the container 1 with the supercritical fluid 10 ', and the supercritical fluid atmosphere 10' is exposed to the parts 20 to which the residual resin A is attached. 'Residual resin A is decomposed by contact with
Since the residual resin A attached to the component 20 is removed by diffusing the decomposed component A ′ into the supercritical fluid atmosphere, the residual resin can be removed evenly over the details of the component 20, and by the metal brush. Since it is not friction cleaning, there is no concern about scratches on the surface or peeling of the coating, and the time required for cleaning work can be shortened.

Further, water (H ₂ O) is used as the liquid solvent 10.
, The cost of liquid solvent (that is, water) is low, the cost of cleaning can be kept low,
Further, since the residual resin is not decomposed by using, for example, chemicals, the safety is high and the handling is easy.

Next, another embodiment of the present invention will be described with reference to FIG. According to this embodiment, the residual resin A adhering to the resin flow passage 21 of the extruder is removed and the extruder is cleaned without removing the parts from the extruder. By sealing the passage and filling the inside of the resin passage 21 with the supercritical fluid 10 ',
The residual resin A adhering to the resin flow path 21 is transferred to the supercritical fluid 10 '.
It disassembles and removes it and cleans the extruder.

In FIG. 4, the resin flow path 21 has a supercritical fluid 10 '.
It is sectional drawing which shows the extruder 100 filled with. Figure 4
The heater 104 uses the resin material supplied from the hopper 101.
1 shows an extruder 100 that is heated and melted by a method of extruding and molding a molten resin from a die 107 at the tip, and a residue attached to a resin flow path 21 from a hopper 101 of this extruder 100 to a die 107. When removing and cleaning the resin A, a sealing member 1 capable of sealing the resin flow path 21 from the hopper 101 to the die 107.
2 and a pressure pump 31 that is connected to the resin flow channel 21 and adjusts the pressure in the resin flow channel 21. After the liquid solvent 10 is injected into the resin flow channel 21, the resin flow channel 21 And the pressurizing pump 31 and the heater 1 of the extruder.
04 to activate a critical temperature (Tc)
By maintaining the pressure above the critical pressure (Pc), the liquid solvent 10 injected into the resin flow path 21 is prevented from flowing into the supercritical fluid 10
The state is changed to 'and the resin flow path 21 is filled with the supercritical fluid atmosphere 10'.

In the embodiment shown in FIG. 4, the resin flow path 21
A pressure gauge 51 for monitoring the internal pressure is provided,
The heater 104 is designed so that the pressure in the resin flow passage 21 can be set and maintained at a predetermined value, and
There is provided a temperature adjusting mechanism (not shown) that operates according to the temperature inside 1 to adjust the temperature inside the resin passage 21 to a predetermined value.

In this embodiment, water (H ₂ O) is injected into the resin passage 21 as the liquid solvent 10 and the pressure pump 31
And the heater 104 are operated to set the temperature in the resin flow passage 21 to 40
Supercritical water (supercritical fluid) 10 is set in the sealed resin flow passage 21 by setting and maintaining 0 ° C. and a pressure of 250 kgf / m ² to change the state of water (H ₂ O) in the resin flow passage 21. Fill with ´. As a result, the inside of the resin flow passage 21 is exposed to the supercritical water (supercritical fluid) atmosphere, and the entire resin flow passage (over the details of the parts) comes into contact with the supercritical water (supercritical fluid).

By the contact with the supercritical water (supercritical fluid) 10 ', the residual resin A adhering in the resin passage 21 is decomposed, and the decomposed component A'is supercritical water (supercritical fluid). ) The residual resin A diffused in the 10 'atmosphere and attached inside the resin flow path 21 is removed.

In the embodiment shown in FIG. 4, the pressure pump 3
1 and the heater 104 are activated to set the temperature in the resin flow passage 21 to 40
The temperature is maintained at 0 ° C. and a pressure of 250 kgf / m ² for 20 minutes, and the inside of the resin flow path 21 to which the residual resin A is attached is exposed to a supercritical water (supercritical fluid) atmosphere 10 ′ for 20 minutes, and the supercritical water (supercritical water The residual resin A adhering to the resin flow channel 21 is decomposed by contacting with the (critical fluid) for 20 minutes, and the decomposition component A ′
Is diffused into the supercritical water (supercritical fluid) atmosphere 10 'to remove the residual resin adhering to the resin flow path 21.

Critical temperature (Tc) and critical pressure (Pc)
By lowering the temperature / pressure in the resin flow path 21 set / maintained above and returning to normal temperature / normal pressure, the supercritical fluid 1
By changing the state of 0 ′ into a liquid, the liquid solvent 10 containing the decomposition component A ′ can be retained in the resin flow path 21, and by discharging this sewage (the liquid solvent 10 containing the decomposition component A ′). The inside of the resin flow path 21 is cleaned.

Therefore, in this embodiment, after sealing the resin channel 21 into which the liquid solvent 10 is injected, the resin channel 21 is sealed.
By maintaining the inside of the liquid at a critical temperature (Tc) / critical pressure (Pc) or higher, the state of the liquid solvent 10 is changed and the resin flow path 2
1 is filled with the supercritical fluid 10 ′, and the entire resin flow passage 21 to which the residual resin A is attached is exposed (contacted) to the supercritical fluid atmosphere 10 ′ to remove the residual resin A attached to the resin flow passage 21. Disassemble, diffuse and remove. by this,
The residual resin A adhering to the details in the resin passage 21 can be evenly and easily removed. Further, since it is not a friction cleaning with a metal brush, there is no fear of scratching the surface or peeling of the coating, and the cleaning time is short.

Furthermore, when water (H ₂ O) is used as the liquid solvent, the cost of the liquid solvent (that is, water) is low, and the cost for cleaning work can be kept low.
For example, since the residual resin is not decomposed by using chemicals or the like, the safety is high and the handling is easy.

[0034]

As described above, in the method for cleaning the parts of the extruder according to the present invention, the resin adhered to the parts of the extruder is decomposed by the supercritical fluid and the decomposed components are diffused into the supercritical fluid. The residual resin can be removed evenly in every detail, and since it is not friction cleaning with a metal brush, there is no risk of scratches on the surface or peeling of the coating, and the time required for cleaning work is short. is there. Further, in the cleaning method of contacting with supercritical water to remove the residual resin adhering to the resin flow path or parts of the extruder, the cost of the liquid solvent (that is, water) is low, so the cost of cleaning work can be kept low. Moreover, since the residual resin is not decomposed by using, for example, a chemical agent, the safety is high and the handling is easy.

[Brief description of drawings]

FIG. 1 is a diagram illustrating a method of cleaning parts of an extruder according to an embodiment of the present invention.

FIG. 2 is a diagram showing a state where the inside of the container is filled with supercritical water.

FIG. 3 is a view showing a state in which supercritical water filled in a container is changed into a liquid state.

FIG. 4 is a diagram illustrating a method for cleaning an extruder according to another embodiment of the present invention.

FIG. 5 is a sectional view of the extruder.

[Explanation of symbols]

1 Container 2 Constant Temperature Bath 3,31 Pressurizing Pump 4 Thermometer 5,51 Pressure Gauge 6 Placement Table 10 Water (H ₂ O) 10 'Supercritical Water A Residual Resin A' Decomposition Component

Claims (5)

[Claims] 1. A residual resin (A) attached to a part of an extruder.
Is decomposed by contacting it with a supercritical fluid (10 '), and the decomposed component (A') in a supercritical fluid atmosphere (10
A method for cleaning an extruder or its parts, characterized in that residual resin (A) attached to parts of the extruder is removed by diffusing it into ′). 2. A liquid solvent (10) is injected into a container (1), which is connected to a pressurizing pump (3) and is placed in a constant temperature bath (2), and which can be sealed. ), After placing the parts (20) of the extruder to which the residual resin (A) has adhered, the container (1) is sealed, and the constant temperature tank (2) and the pressure pump (3) are operated. ,
By maintaining the inside of the container (1) at or above the critical temperature (Tc) and the critical pressure (Pc), the state of the liquid solvent (10) is changed and the inside of the container (1) is in the supercritical fluid atmosphere (10 ′). The residual resin (A) adhering to the component (20) is decomposed by contacting the supercritical fluid (10 ′) with the supercritical fluid (10 ′) and the decomposed component (A ′) in the supercritical fluid atmosphere (10).
′) To remove the residual resin (A) adhering to the part (20), and then lower the temperature and pressure in the container (1) to decompose the decomposition component (A ′) into a supercritical state. The fluid (10A) is changed into a liquid state, and the liquid solvent (1 containing the decomposition component (A ′) is used.
0) is retained at the bottom of the container (1), a method for cleaning extruder parts. 3. Water (H ₂ O) as a liquid solvent (10) is injected into the container (1), and the thermostatic chamber (2) and the pressure pump (3) are operated to make the inside of the container (1) critical. The extruder part according to claim 2, wherein the container (1) is filled with a supercritical water atmosphere (10 ') by maintaining the temperature (Tc) and the critical pressure (Pc) or higher. Cleaning method. 4. A resin flow path (21) of an extruder for heating and melting a resin material supplied from a hopper (101) by a heater (104) and extruding the molten resin from a die (107) at the tip to perform molding. ) Residual resin (A)
A method of removing and cleaning the resin flow path (21) from the hopper (101) to the die (107), and a sealing member (12) capable of sealing the resin flow path (21). A pressure pump (31) for adjusting the pressure in the resin flow channel (21) is provided, and after the liquid solvent (10) is injected into the resin flow channel (21), the resin flow channel (21) is sealed. Then, the pressure pump (31) and the heater (104) are further operated to maintain the inside of the resin flow path (21) at a critical temperature (Tc) / critical pressure (Pc) or higher, whereby the liquid solvent (1)
0) is changed to a supercritical fluid (10 ′), the resin flow channel (21) is filled with a supercritical fluid atmosphere (10 ′), and the supercritical fluid (10 ′) is brought into contact with the resin to form a resin. The residual resin (A) adhering to the inside of the flow channel (21) is decomposed, and this decomposition component (A ′) is diffused into the supercritical fluid atmosphere (10 ′), so that the resin flow channel (21) is The residual resin (A) that has adhered is removed, and then the temperature and pressure inside the resin flow channel (21) are lowered to turn the supercritical fluid (10 ') in which the decomposition component (A') is diffused into a liquid state. After changing the liquid solvent (10) containing the decomposition component (A ′) and allowing it to stay in the resin flow channel (21), the liquid solvent (10) containing the decomposition component (A ′) is changed into the resin flow channel. (21) A method for cleaning an extruder, which comprises discharging from inside. 5. Water (H ₂ O) as a liquid solvent (10) is injected into the resin channel (21), and the pressure pump (31) and the heater (104) are operated to activate the resin channel (21). By maintaining the internal temperature above the critical temperature (Tc) and critical pressure (Pc),
The method for cleaning an extruder according to claim 4, wherein the resin flow channel (21) is filled with a supercritical water atmosphere (10 ').