JP6638481B2 - Elastomer drying method, elastomer production method, elastomer drying apparatus and elastomer production apparatus - Google Patents

Description

  The present invention relates to a method for drying an elastomer, a method for producing an elastomer, an apparatus for drying an elastomer, and an apparatus for producing an elastomer.

  In the process of producing an elastomer, a slurry containing an elastomer that has been polymerized and coagulated contains a large amount of water. In order to ship an elastomer as a product, it is necessary to dehydrate and dry it. As an apparatus for drying an elastomer in a manufacturing process, for example, an apparatus disclosed in Patent Document 1 is known.

  However, the conventional elastomer drying apparatus and the conventional drying method have a problem that the elastomer fine powder adheres and deposits on the inner surface of the wall of the drying chamber. If the sediment of the fine powder of the elastomer adhering to the inner surface of the wall of the drying chamber is left as it is, the sediment may be peeled off and fall, mixed into the elastomer product being dried, and become a foreign substance.

JP-A-11-198137

  The present invention has been made in view of such circumstances, and a first object of the present invention is to provide a method and an apparatus for drying an elastomer which can prevent adhesion of elastomer fine powder to an inner surface of a wall of a drying chamber. . Further, a second object of the present invention is to provide a method and an apparatus for producing an elastomer, in which foreign matter is less mixed in a step of drying the elastomer.

  The present inventors have found that fine particles of the elastomer may adhere to even the inner surface of the fluororesin-coated wall to form deposits, and that the deposits are formed in water droplets on the hydrophobic surface. And completed the present invention.

  That is, in order to achieve the first object, the method for drying an elastomer according to the present invention comprises drying the elastomer in a state where the inner surface of a wall constituting a drying chamber for drying the elastomer in a manufacturing process is wetted with water. It is characterized by making it.

In order to achieve the first object, the elastomer drying device of the present invention comprises:
A drying chamber into which the elastomer in the manufacturing process is charged and the elastomer is dried inside,
A dew-water generating means for generating dew-water on the inner surface of a wall constituting the drying chamber and wetting the inner surface of the wall with water.

  According to the method and apparatus for drying an elastomer of the present invention, since the inner surface of the wall constituting the drying chamber is wet with water, during the drying of the elastomer, the fine powder of the elastomer that is to adhere to the inner surface of the wall is Falls down with the water present on the inner surface of the. Therefore, it is possible to prevent the fine powder of the elastomer from gradually adhering and depositing on the inner surface of the wall, and it is possible to reduce the possibility that the deposit is peeled off and mixed into the elastomer being dried.

  In the present invention, the state in which the inner surface of the wall is wetted with water does not mean a state in which water droplets are scattered on a hydrophobic surface such as a fluororesin-coated surface and then is dried. Is always present in a hydrophilic state.

  Conventionally, in the early stage of the drying operation, water droplets are formed on a hydrophobic surface such as a fluororesin coating surface, and the fine powder of the elastomer adheres to the water droplets. Fine particles of the elastomer are pulled to the inner surface. Thereafter, it is considered that the fine particles of the elastomer attracted to the inner surface of the wall are thermally deformed and adhere to the inner surface of the wall, and the fine particles of the elastomer further accumulate thereon. If the deposit of the accumulated and thermally deformed and deteriorated elastomer falls and mixes with the elastomer being dried, it becomes a foreign substance in the elastomer product.

  In the present invention, for example, by cooling the inner surface of the wall from the outside of the wall, dew condensation water can be constantly generated on the inner surface of the wall to wet the inner surface of the wall. Since the elastomer in the manufacturing process originally contains moisture, if the moisture evaporated from the elastomer in the manufacturing process is generated as dew condensation on the inner surface of the wall, the moisture is always supplied to the inner surface of the wall during the drying process. be able to. Thus, in the present invention, the fine particles of the elastomer that are to adhere to the inner surface of the wall fall down with the water present on the inner surface of the wall. Therefore, it is possible to prevent the fine powder of the elastomer from gradually adhering and depositing on the inner surface of the wall, and it is possible to reduce the possibility that the deposit is peeled off and mixed into the elastomer being dried.

  As an example of a method for drying the elastomer, inside the drying chamber, the crumb of the elastomer may be blown out of the extruder at a temperature of 100 to 180 ° C., guided on a conveyor, and dried.

  Preferably, the inner surface of the wall is made of a hydrophilic material or has been subjected to a hydrophilic treatment. With this configuration, the inner surface of the wall is easily wetted with water, and the possibility that the fine powder of the elastomer adheres to the inner surface of the wall can be reduced.

  Preferably, the dew condensation water generating means is a cooling means for cooling an inner surface of the wall from outside the wall. Since water is contained in the elastomer in the manufacturing process, if the moisture evaporated from the elastomer in the manufacturing process is generated as dew condensation on the inner surface of the wall, the water is always supplied to the inner surface of the wall during the drying process. Can be.

The drying device for the elastomer of the present invention,
An extruder for flipping the elastomer into the drying chamber;
A conveyor that conveys the elastomer ejected from the extruder.

  In order to achieve the second object of the present invention, a method for producing an elastomer of the present invention includes a step of drying an elastomer by any of the above-described methods for drying an elastomer.

  In order to achieve the second object of the present invention, an apparatus for producing an elastomer of the present invention has the above-described apparatus for drying an elastomer.

  ADVANTAGE OF THE INVENTION In the manufacturing method and manufacturing apparatus of the elastomer of this invention, in the drying process of an elastomer, the mixture of the sediment from the inner surface of the wall of the drying chamber can be prevented, and a high-quality elastomer with less mixture of foreign substances can be manufactured. it can.

FIG. 1 is a schematic diagram of an apparatus for drying an elastomer according to an embodiment of the present invention.

  Hereinafter, the present invention will be described based on embodiments shown in the drawings.

  As shown in FIG. 1, the elastomer drying device 2 according to the present embodiment includes a dehydrator 4, an extruder 6, and a drying chamber 20.

  The dehydrator 4 is not particularly limited. For example, a dehydrator that squeezes the water to the outside of the barrel while feeding the elastomer slurry containing the water in the axial direction with a screw is used. The elastomer containing a large amount of water supplied from the polymerization tank is supplied to a dehydrator after water is removed by, for example, a vibrating screen. The water separated by the screen is returned as hot water.

  As a result of the separation of water by the second vibrating screen, the water content of the elastomer before being supplied to the dehydrator 4 is about 50% by weight. In the dehydrator 4, the water can be dried to about 8 to 12% by weight. The elastomer dehydrated by the dehydrator 4 is supplied to the hopper of the extruder 6.

The hopper of the extruder 6 has a drain hole, and a part of the water contained in the elastomer is discharged from the drain hole. Conveyed to the center and not discharged on the way. The die part 9, and the die roll and the orienter 10 is disposed in pairs.

  The number of dies and orienters 10 is not particularly limited, but is about 5 pairs in the present embodiment. The elastomer fed to the die portion 9 by the screw 8 is discharged from the orienter 10 through a hole in the die. Since there is no discharge port other than the die in the middle of the barrel 7 and in the die portion 9, the pressure of the elastomer in the die portion 9 is 4 to 9 MPa.

  In this extruder 6, the temperature of the elastomer is raised by viscous heating of the elastomer by rotation of the screw 8 and heating by the barrel jacket. The temperature of the elastomer is controlled by controlling the temperature of the heating fluid flowing inside the barrel jacket. The temperature at the die section 9 (outlet temperature) depends on the type, molecular weight, Mooney viscosity, etc. of the elastomer. For example, in the case of butadiene rubber (BR), the styrene- In the case of butadiene rubber (SBR), the temperature is generally controlled to 130 to 170 ° C. That is, inside the drying chamber 20, the elastomer crumb is ejected from the orienter 10 at a temperature of 100 to 180 ° C.

  These temperatures are determined so that the water content of the elastomer discharged from the extruder 6 is 4 to 7% by weight, and differs depending on the kind of the elastomer to be obtained. As described above, the temperature of the die portion 9 is high and high, and the pressure of the die portion 9 is always higher than the water vapor pressure of the water in the elastomer. When the elastomer and water in the die portion are released from the die, the moisture becomes vapor, and the elastomer is ejected from the die in a porous state. The orienter 10 has an orienting passage of a predetermined length, and is adapted to orient the direction in which the crumb-like elastomer discharged from the discharge hole of the die projects.

  The orienter 10 mounted on the outlet side of the extruder 6 extends to the inside of the drying chamber 20. In the inside of the drying chamber 20, a chin cap member 22 as a dispersing member is provided in front of the outlet of the orienter 10. It is arranged. The chin cap member 22 has a conical shape in the present embodiment. The kin cap member 22 is arranged such that its axis is inclined at a predetermined angle with respect to a horizontal axis substantially parallel to the axis of the extruder. The adjustment of the angle is performed by adjusting the lengths and mounting positions of two or more adjustment rods that suspend the chin cap member 22 from the ceiling.

  The distance between the orienter 10 and the chin cap member 22 (the distance until the elastomer discharged from the orienter 10 collides with the chin cap member 22) is preferably about 500 to 1500 mm. The crumb-like elastomer (elastomer in the manufacturing process) discharged from the orienter 10 collides with the peripheral surface of the rinsing member 22, and travels to the conveyor porous belt 24 disposed in the drying chamber 20, and is placed thereon. , Are uniformly dispersed and deposited.

  The drying chamber 20 has a perforated belt 24 that is moved in the transport direction A by a roller. The porous belt 24 is made of, for example, a stainless steel plate having holes formed with an aperture ratio of about 30 to 40%. The size of the holes is such that the crumb-like elastomer 12 deposited on the belt 24 does not drop. A nozzle (not shown) is arranged below the belt 24, and drying air is blown from the nozzle from the back surface of the belt 24 on which the elastomer 12 is deposited. In this embodiment, the temperature of the drying air is about 50 to 95 ° C.

  In the present embodiment, as shown in FIG. 1, the belt 24 on which the elastomer 12 is deposited, the kinshasa member 22, and the orienter 10 are configured to be covered by a housing wall 30. The temperature is kept constant, and the drying efficiency in the drying chamber 20 is improved.

  At least a part of the housing wall 30, in particular, the outside of the housing wall 30 a facing the orienter 10, is provided with a heat exchanger 40 as cooling means. The heat exchanger 40 is configured to cool the housing wall 30a from the outside, cool the inner surface of the wall 30a, and generate dew condensation on at least the inner surface of the wall 30a. That is, the heat exchanger 40 functions as dew condensation water generating means.

  The heat exchanger 40 may be provided at least partially outside the housing wall 30, but may be configured to cover the entire housing wall 30 from outside. The reason that at least the dew condensation water is generated on the inner surface of the housing wall 30a facing the orienter 10 is to prevent the elastomer fine powder from adhering to this portion most easily.

  A cooling device 42 for cooling the refrigerant is connected to the heat exchanger 40, and the cooled refrigerant passes through the heat exchanger 40 to cool at least the wall 30a from the outside. Therefore, when the elastomer 12 is dried inside the drying chamber 20, dew condensation water can always be generated on the inner surface of the wall 30a.

  Note that the inner surface of the housing wall 30a that generates dew condensation water is made of a hydrophilic material or has been subjected to a hydrophilic treatment, so that the wettability with water is improved. For example, the housing wall 30a is preferably made of a metal such as stainless steel, iron, nickel, aluminum, chromium, copper, and various other metal alloys. With such a metal, the wettability to water is improved, and the thermal conductivity is improved. By cooling from the outside of the housing wall 30a, dew condensation water is easily generated on the inner surface of the wall 30a.

  The housing wall 30a may be made of a material other than metal, for example, a ceramic material such as alumina or zirconia, a glass material such as borosilicate glass or quartz glass, a resin material such as epoxy resin, ABS, or PET. The inner surface of the housing wall 30a may be subjected to a treatment such as silanol treatment, alkali treatment, application of a hydrophilic paint, adhesion of a hydrophilic film, corona discharge, or the like to perform a hydrophilic treatment. Further, the surface roughness of the inner surface of the housing wall 30 may be controlled so that the wettability to water is improved, and the control of the surface roughness may be used in combination with the hydrophilic treatment, and the surface roughness control alone may be used. The wettability with water may be improved. Note that the entire housing wall 30 may be constituted by a housing wall 30a in which dew condensation water is generated.

  The dried elastomer 12 deposited on the belt 24 is peeled off from the surface of the belt 24, crushed, and discharged to the measuring section. The dried elastomer is weighed by a weighing unit, molded, subjected to an appearance inspection, and then packed and shipped. Alternatively, the dried elastomer (for example, rubber) 12 is compressed, formed into, for example, a rubber veil, and then packed and shipped.

  As described above, the water content of the elastomer supplied to the dehydrator 4 shown in FIG. 1 is about 50% by weight. This elastomer is dehydrated by the dehydrator 4, and the water content of the elastomer becomes about 8 to 12% by weight. This elastomer is supplied into the extruder 6 and fed by the screw 8 inside, whereby the elastomer containing water is compressed to a pressure higher than the water vapor pressure. For this reason, when the elastomer containing water is released into the atmosphere from a die (not shown), it expands and ruptures, and the moisture becomes steam, and the elastomer becomes a porous crumb-like elastomer.

  The crumb-like elastomer discharged from the die is adjusted in the discharge direction by the orienter 10 and collides with the chin cap member 22. The crumb-shaped elastomer that has collided with the peripheral surface of the kinkasa member 22 is uniformly scattered on the porous belt 24 of the drying chamber 20. As the porous belt 24 moves, the crumb-like elastomer 12 scattered thereon and having a predetermined thickness moves in the transport direction A, and is exposed to drying air blown up from below during the movement. The drying air passes through the crumb-like elastomer 12 having a predetermined thickness from the porosity of the belt, and dries the elastomer.

  According to the elastomer drying method and the drying apparatus 2 of the present embodiment, the inner surface of the housing wall 30a constituting the drying chamber 20 is wet with the dew condensation water. The fine particles of the elastomer to be attached fall down together with the dew water present on the inner surface of the wall 30a.

  Therefore, it is possible to prevent the fine powder of the elastomer from gradually adhering and depositing on the inner surface of the wall 30a, and to reduce the possibility that the deposits (including the thermally denatured and deteriorated products of the elastomer) are peeled off and mixed into the elastomer 12 being dried. Can be. In addition, there is no problem that the fine powder of the elastomer that drops together with the dew condensation water is mixed into the elastomer 12 during drying. Even if the fine powder of the elastomer before deterioration is mixed into the elastomer 12 or dried together with the elastomer 12, it does not become a foreign substance.

  In the present embodiment, the state in which the inner surface of the wall 30a is wetted with water does not mean a state in which water droplets are scattered on a hydrophobic surface such as a fluororesin-coated surface and then is dried. Means that water is always present in a hydrophilic state on the inner surface of.

  Conventionally, in the early stage of the drying operation, water droplets are formed on a hydrophobic surface such as a fluororesin coating surface, and the fine powder of the elastomer adheres to the water droplets. Fine particles of the elastomer are pulled to the inner surface. Thereafter, it is considered that the fine particles of the elastomer attracted to the inner surface of the wall are thermally deformed and adhere to the inner surface of the wall, and the fine particles of the elastomer further accumulate thereon. If the deposit of the accumulated and thermally deformed and deteriorated elastomer falls and mixes with the elastomer being dried, it becomes a foreign substance in the elastomer product.

  In the present embodiment, for example, by cooling the inner surface of the wall 30a from the outside of the wall 30a, dew condensation water can be constantly generated on the inner surface of the wall 30a to wet the inner surface of the wall. Since moisture is originally contained in the elastomer 12 during the manufacturing process, if the moisture evaporated from the elastomer 12 during the manufacturing process is generated as dew condensation on the inner surface of the wall, the moisture is constantly applied to the inner surface of the wall during the drying process. Can be supplied. Therefore, in the present embodiment, the fine powder of the elastomer that is going to adhere to the inner surface of the wall 30a falls down together with the water existing on the inner surface of the wall 30a. Therefore, it is possible to prevent the fine powder of the elastomer from gradually adhering and accumulating on the inner surface of the wall 30a, and it is possible to reduce the possibility that the sediment is peeled off and mixed into the elastomer 12 during drying.

  The elastomer to be dried using the drying method of the present embodiment is not particularly limited as long as it is a polymer having rubber elasticity, and examples thereof include a so-called synthetic rubber and a thermoplastic elastomer, which can be widely applied to these elastomers. Specifically, synthetic rubber such as styrene-butadiene rubber (SBR), nitrile-butadiene rubber (NBR), butadiene rubber (BR), isoprene rubber (IR), acrylic rubber, polyether rubber, hydrin rubber; Widely applicable to general synthetic rubbers and thermoplastic elastomers such as isoprene-styrene block polymer (SIS), thermoplastic elastomers such as styrene-butadiene-styrene block polymer (SBS), and hydrogenated block polymers thereof. .

  In the elastomer manufacturing method and the manufacturing apparatus according to the present embodiment, in the elastomer drying step, it is possible to prevent the sediment from being mixed from the inner surface of the wall 30a of the drying chamber 20 and to prevent the foreign matter from being mixed into a high-quality elastomer (for example, Rubber veil).

  Note that the present invention is not limited to the above-described embodiment, and can be variously modified within the scope of the present invention. For example, the dew condensation water generating means used to wet the inner surface of the wall 30a with water is not limited to the heat exchanger 40, but may be Peltier element cooling or the like. In addition, as a method for wetting the inner surface of the wall 30a with water, a method of spraying mist or fog, a method of continuously flowing water from the upper part of the wall, or the like is used as a method other than generating dew condensation water. is there.

  Hereinafter, the present invention will be described based on more detailed examples, but the present invention is not limited to these examples.

Example 1
As the elastomer of Example 1, SBR produced by solution polymerization, having an average molecular weight of 20.0 × 10 ⁴ and a Mooney viscosity (JIS K6300) of 50 was used. This SBR was dried using the apparatus shown in FIG. The water content of the rubber supplied to the dehydrator 4 was 50% by weight.

  The water content of the rubber after dehydration by the dehydrator 4 was 10% by weight. The rubber having a water content of 10% by weight was dried by the extruder 6. The outlet temperature of the extruder 6 was set at 130 ° C.

  When the water content of the rubber discharged from the die was examined, it was 5% by weight. The rubber having a water content of 5% by weight was caused to collide with the kinshade member 22 shown in FIG. 1 to be uniformly dispersed and deposited on the porous belt 24 of the drying chamber 20.

  The water content of the rubber after drying in the drying chamber 20 was 0.2% by weight. The water content of the rubber was measured in accordance with JIS-K-6383 according to JIS-K-6383. The crumb was dried at 105 ° C. ± 5 ° C. for 1 hour, and then allowed to cool in a desiccator. (Water content) / (water content + polymer before and after drying) was calculated in percentage.

  Visual observation of the rubber thus dried confirmed that no thermal degradation was observed and that the rubber was a porous rubber that did not powder. No foreign matter was observed in the 20,000 kg rubber. No accumulation of rubber fine powder was observed on the inner surface of the wall 30a after the operation for 10 hours.

Comparative Example 1
Rubber was produced under the same conditions as in Example 1 except that the heat exchanger 40 was not attached, and the same evaluation was performed. The rubber was observed to be contaminated with foreign substances, which are considered to be fine powder deposits. Further, accumulation of rubber fine powder was observed on the inner surface of the wall 30a.

Example 2 and Comparative Example 2
The same evaluation was performed as in Example 1 and Comparative Example 1 except that the type of the elastomer was changed to NBR (Nipol DN3350 manufactured by Zeon Corporation, manufactured by emulsion polymerization, Mooney viscosity: 50), and similar results were obtained.

Example 3 and Comparative Example 3
When the same evaluation was performed as in Example 1 and Comparative Example 1 by changing the type of the elastomer to BR (Nipol BR1220 manufactured by Zeon Corporation, manufactured by solution polymerization, Mooney viscosity: 44), similar results were obtained.

Example 4 and Comparative Example 4
When the same evaluation was performed as in Example 1 and Comparative Example 1 except that the type of the elastomer was changed to IR (Nipol IR2200 manufactured by Zeon Corporation, manufactured by solution polymerization, Mooney viscosity: 82), similar results were obtained.

2. Drying device 4 Dehydrator 6 Extruder 10 Orienter 12 Elastomer 20 Drying room 22 Jinkasa member 24 Porous belt 30, 30a Wall 40 Heat exchanger (cooling means, dew water generating means)

Claims (9)

  A method for drying an elastomer, characterized in that the elastomer is dried while the inner surface of a wall constituting a drying chamber for drying the elastomer in a manufacturing process is wetted with water.   The method for drying an elastomer according to claim 1, wherein the inner surface of the wall is cooled from the outside of the wall to generate dew condensation on the inner surface of the wall to wet the inner surface of the wall.   3. The method for drying an elastomer according to claim 1, wherein, inside the drying chamber, the elastomer crumb is blown out of the extruder at a temperature of 100 to 180 [deg.] C., guided on a conveyor, and dried.   The method for drying an elastomer according to any one of claims 1 to 3, wherein an inner surface of the wall is made of a hydrophilic material or is subjected to a hydrophilic treatment.   A method for producing an elastomer, comprising a step of drying the elastomer by the method for drying an elastomer according to claim 1. A drying chamber into which the elastomer in the manufacturing process is charged and the elastomer is dried inside,
An apparatus for drying an elastomer, comprising: dew water generating means for generating dew water on an inner surface of a wall constituting the drying chamber to wet the inner surface of the wall with water.   The drying apparatus for an elastomer according to claim 6, wherein the dew condensation water generating unit is a cooling unit that cools an inner surface of the wall from outside the wall. An extruder for flipping the elastomer into the drying chamber;
The apparatus for drying an elastomer according to claim 6 or 7, further comprising: a conveyor for conveying the elastomer ejected from the extruder.   An apparatus for producing an elastomer, comprising the apparatus for drying an elastomer according to claim 6.

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