JP4929618B2 - Method for producing rubbery polymer - Google Patents

Description

  The present invention relates to a method for producing a rubbery polymer by adding a coagulant to a polymer latex and coagulating a rubbery polymer component.

  In the process of producing a rubbery polymer from the polymer latex obtained by emulsion polymerization, for example, as shown in FIG. The rubber-like polymer component is deposited by the washing device 1 and washed, then dehydrated by the squeezer 8, and then dried by a drying device such as a band dryer, an air dryer or an extrusion dryer. Have gained. In addition, a baler is usually connected to the downstream side of the drying apparatus, and the rubber-like polymer after drying is finally processed into a bale-like product in many cases.

  However, in the process of producing a rubber-like polymer as shown in FIG. 7, a coagulation / cleaning apparatus comprising a large coagulation tank and a washing tank is required, so that the operation is complicated, the operability is poor, and A large amount of installation space is required, which increases equipment costs and manufacturing costs.

  In order to solve this problem, for example, in Patent Document 1, in a method for producing a rubber-like polymer by adding a coagulating liquid to a cement-like rubber solution, a cement-like pump is used to produce a cement-like rubber solution. A method is disclosed in which a rubber-like polymer component is precipitated by bringing a rubber solution into contact with a coagulation liquid. According to the invention described in this document, it is described that the operability is improved, the manufacturing process and the manufacturing equipment can be reduced, and the equipment cost and the manufacturing cost can be reduced. However, the method disclosed in this document is a method for producing a rubber-like polymer from a cement-like rubber solution obtained by solution polymerization. Further, in this document, the dehydration and drying of the rubber-like polymer is performed. However, there is a problem that the manufacturing cost becomes high.

JP-A-10-100135

  The present invention was made in view of such a situation, and in a method for producing a rubbery polymer by adding a coagulant to a polymer latex and coagulating a rubbery polymer component, an improvement in operability and a production process In addition, it is possible to reduce manufacturing equipment, and to reduce facility costs and manufacturing costs.

  The present inventors use a mixer with a stirring / crushing function having a predetermined stirring power for a crumb slurry obtained by adding a coagulant to a polymer latex, and a rubber-like polymer contained in the crumb slurry. It was found that the above-mentioned object can be achieved by stirring and crushing, and the present invention has been completed.

That is, the method for producing the rubber-like polymer of the present invention comprises:
Contacting the polymer latex with a coagulating liquid containing a coagulant to coagulate the rubbery polymer component to obtain a crumb slurry containing a crumb-like rubbery polymer;
The crumb slurry is discharged into a tank having a mixer with a stirring / crushing function whose stirring power is 1 kW / m ³ or more, and in the tank, the rubber-like polymer contained in the crumb slurry is discharged by the mixer. And a step of stirring and crushing.

In the present invention, the crumb slurry obtained by adding a coagulant to the polymer latex is stirred and retained in a tank using a mixer with a stirring and crushing function whose stirring power is 1 kW / m ³ or more. Thus, the contact of the coagulant can be promoted, and the solidification of the rubber-like polymer component can be almost completely advanced. In particular, in the present invention, since a mixer with a stirring / crushing function having a stirring power of 1 kW / m ³ or more is used, the contact of the coagulant with the rubber-like polymer component can be promoted, and the rubber-like polymer. The components can be solidified efficiently. Therefore, the tank can be downsized. Accordingly, since a coagulating apparatus composed of a large tank that has been conventionally used is not required, it is possible to reduce the manufacturing process and the manufacturing equipment, thereby reducing the equipment cost and the manufacturing cost. Further, in the present invention, since the above mixer with stirring and crushing function is used, the dispersibility of the rubber-like polymer can be improved, and further, the rubber-like polymer adheres to the inside of the mixer or the tank. It can also be effectively prevented.

In addition, although it does not specifically limit as such a mixer with stirring power of 1 kW / m < ³ > or more, The high shear mixer which has a stirring and crushing part provided with the rotary blade and the fixed blade is preferable.

  In the present invention, it is preferable that the agitation / crushing part of the mixer with agitation / crushing function is formed on the side wall or bottom of the tank. There is no need to place them. Therefore, adhesion of the rubber-like polymer to the stirring blade, which has been a problem in the past, can be prevented. The agitation / crushing part may be arranged on either the tank side wall part or the bottom part, but considering the convection of the slurry during the agitation, it is more preferable that the agitation / crushing part is arranged on the bottom part. In addition, the said bottom part means the part below TL (tangent line) of a tank, and in the case of a flat bottom tank, it means the bottom horizontal with respect to the ground.

  In the present invention, when the rubber-like polymer contained in the crumb slurry is stirred and crushed in the tank having the mixer with the stirring and pulverizing function, the liquid phase portion in the tank has a rubber-like shape. It is preferable to blow 15 to 250 parts by weight of steam with respect to 100 parts by weight of the polymer supplied. By blowing steam into the tank and performing steam coagulation in this way, the contact of the coagulant with the rubbery polymer component can be further promoted, and the rubbery polymer component remaining in the crumb slurry can be coagulated. Can proceed almost completely in a shorter time.

  In the present invention, it is preferable that the polymer latex and the coagulation liquid are supplied to a pump having a crushing function, and the polymer latex and the coagulation liquid are brought into contact with each other inside the pump. By making the contact between the polymer latex and the coagulating liquid using such a pump having a crushing function, it is possible to further reduce the manufacturing process and equipment.

  The pump with a crushing function may be any pump that can coagulate the polymer by bringing the polymer latex into contact with the coagulating liquid and crush the crumb slurry obtained thereby. Moreover, what is equipped with the rotary blade which has a function which discharges | emits the said crumb slurry outside a pump is preferable.

  In the present invention, for example, when using a pump equipped with the rotor blades, the polymer latex and the coagulant are supplied to the rotor blades in the flow direction, and the polymer latex and the coagulation liquid rotate. It is preferable to contact before contacting the wing. With such a configuration, the rubber-like polymer is solidified before the flow direction with respect to the rotor blades, and the rubber-like polymer obtained by coagulation is crushed by the rotor blades to an appropriate size outside the pump. It becomes possible to discharge into In addition, the distance from the position where the polymer latex and the coagulating liquid contact to the rotor blade is preferably 50 cm or less, and particularly preferably 40 cm or less. If the distance is too large, clogging may occur in the pump.

In the present invention, preferably, the pump with the crushing function, a first blade for crushing the solidified rubbery polymer component,
A second wing provided on an outer periphery of the first wing;
A through-hole disposed between the first blade and the second blade for discharging the rubber-like polymer component crushed by the first blade from the first blade toward the second blade. And a fixed frame.

  The first blade and the second blade are rotatable rotor blades and have a function of discharging the crumb slurry to the outside of the pump. In the present invention, preferably, together with the first blade, the discharge blade of the pump can be improved by providing the second blade on the outer periphery of the first blade, and the rubber-like polymer component is clogged inside the pump. Can be effectively prevented. Furthermore, by forming a fixed frame between the first blade and the second blade, the rubber-like polymer component crushed to a certain size by the first blade is moved out of the pump by this fixed frame. It can be of an appropriate size for discharging. In addition, a through hole for discharging from the first blade to the second blade is formed in the fixed frame, and the size of the rubbery polymer component obtained by crushing is adjusted by adjusting the size of the through hole. You can control it.

In the present invention, preferably, the crumb slurry is further released into the atmosphere through a pipe from a discharge port of the pump having the crushing function, and then the crumb slurry released into the atmosphere is further discharged to the tank. Have
The ratio (L / D) between the length L of the pipe and the inner diameter D of the discharge port of the pump with the crushing function is 20 or less.

  The dispersibility of the rubber-like polymer crumb in the slurry can be improved by opening the crumb slurry to the atmosphere through the pipe and then discharging the crumb slurry to a tank having a mixer with a stirring and crushing function. Furthermore, it is preferable that the length L of the pipe is such that the ratio (L / D) to the inner diameter D of the discharge port of the pump is 20 or less. It is possible to effectively prevent clogging of the rubbery polymer crumb.

  In this invention, Preferably, it has further the washing | cleaning process which wash | cleans the crumb slurry stirred and crushed with the said mixer with water, and removes the said coagulant | flocculant from a crumb-like rubber-like polymer. In this washing process, the coagulant adhering to the surface of the crumb-like rubbery polymer is removed by supplying washing water to the crumb slurry with a spray nozzle, and moisture and the crumb-like rubbery polymer are removed on the screen. Solid-liquid separation with. Various apparatuses can be used as the apparatus for solid-liquid separation, but it is preferable to use a vibration type screen or a rotary type screen.

  In the present invention, preferably, a dehydration step of removing water from the crumb slurry stirred and crushed by the mixer to obtain a crumb-like rubber polymer, and the crumb-like rubber polymer from which the water has been removed, And a step of heat-drying.

  The polymer latex that can be applied to the method of the present invention is not particularly limited. For example, a homopolymer composed only of a conjugated diene such as a butadiene polymer or an isoprene polymer; only an acrylate such as an ethyl acrylate polymer. In addition to latexes of various homopolymers such as copolymers, copolymers composed only of conjugated dienes such as butadiene / isoprene copolymers; acrylonitrile / butadiene copolymers, acrylonitrile / butadiene / isoprene copolymers Polymer, copolymer composed of unsaturated nitrile such as acrylonitrile / isoprene copolymer, acrylonitrile / styrene / butadiene copolymer, acrylonitrile / styrene / isoprene copolymer and conjugated diene; styrene / butadiene copolymer, Styrene / isoprene copolymer weight Copolymer composed of directional group vinyl and conjugated diene, etc .; composed only of acrylate such as ethyl acrylate / n-butyl acrylate copolymer, ethyl acrylate / n-butyl acrylate / 2-methoxyethyl acrylate copolymer And latexes of various copolymers such as

  Of these, a copolymer composed of an unsaturated nitrile and a conjugated diene, or a polymer latex composed of an acrylate alone or a copolymer is preferred, and a copolymer composed of an unsaturated nitrile and a conjugated diene is preferred. A combined latex is preferably applicable to the present invention.

  The solid content concentration of the polymer latex applicable to the present invention is usually about 5 to 50% by weight, preferably about 10 to 40% by weight.

  The polymer latex applicable to the present invention can be obtained, for example, by emulsion polymerization or fine suspension polymerization. Particularly preferred is an emulsion polymer latex obtained by emulsion polymerization. The particle size of the polymer fine particles obtained by emulsion polymerization and the type and amount of the emulsifier are not particularly limited.

  In the present invention, the coagulant is not particularly limited. For example, inorganic acids such as sulfuric acid and hydrochloric acid; organic acids such as acetic acid; inorganic salts such as calcium chloride, magnesium chloride, magnesium sulfate, aluminum sulfate, and barium chloride; and A mixture of these may be used, but may be determined as appropriate depending on the type of emulsifier used in the polymer latex. Among these, as the coagulant, inorganic salts are preferable, and calcium chloride, magnesium sulfate, and aluminum sulfate are more preferable.

  According to the present invention, a crumb slurry obtained by adding a coagulant to a polymer latex is converted into a rubbery polymer contained in the crumb slurry using a mixer having a stirring and crushing function having a predetermined stirring power. Since the contact of the coagulant is promoted, the rubber-like polymer component can be coagulated efficiently and in a short time. Therefore, it is possible to reduce the size of the manufacturing equipment, and it is possible to reduce equipment costs and manufacturing costs.

Hereinafter, the present invention will be described based on embodiments shown in the drawings.
FIG. 1 is a schematic view of an apparatus for producing a rubbery polymer according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view of a main part of a pump with a crushing function according to an embodiment of the present invention,
FIG. 3 is a schematic view showing a part of a rubber-like polymer production apparatus according to an embodiment of the present invention, and FIG. ,
FIG. 5 (A) is a perspective view of the agitation unit of the mixer with agitation / crushing function according to one embodiment of the present invention, and FIG. 5 (B) is the agitation unit of the mixer with agitation / crushing function according to one embodiment of the present invention. Sectional view of
FIG. 6 is a perspective view of a stirring unit of a mixer with a stirring and crushing function according to another embodiment of the present invention,
FIG. 7 is a schematic view of an apparatus for producing a rubbery polymer according to a conventional example.

  As shown in FIG. 1, the rubber polymer manufacturing apparatus according to an embodiment of the present invention includes a pump 10 with a crushing function, a stirring device 12, a vibrating screen 14, and a squeezer 16.

  As shown in FIG. 2, in the pump 10 with the crushing function, a circular rotating body 30 having a first blade 32 and a second blade 34 is rotatable in a pump casing 24 having a suction port 26 and a discharge port 28. It is attached to. The rotating body 30 is rotationally driven together with the first blade 32 and the second blade 34 by a motor (not shown) connected to the rotating shaft 36. Further, a stator (fixed frame) 38 is disposed between the first blade 32 and the second blade 34 so as to cover the first blade 32.

  A plurality of the first blades 32 and the second blades 34 are provided on the rotating body 30, and rotate together with the rotating body 30 to suck fluid from the suction port 26 and crush and disperse crumbs contained in the fluid. The crushed crumb can be discharged from the discharge port 28 together with the fluid.

  The first blade 32 is a rotary blade for crushing crumbs contained in the fluid sucked from the suction port 26. The first blade 32 only needs to have a structure capable of pulverizing the crumb. Preferably, the shear rate (share rate) applied to the crushed crumb is 200 [1 / s] or more. To do.

  The second blade 34 is a rotary blade for dispersing and discharging the crumb crushed by the first blade 32. The second blade 34 may have a structure that can disperse and discharge the crushed crumb, and is not particularly limited, but crumbs are clogged in the gap between the stator 38 and the pump casing 24. It is preferable that the structure does not occur. That is, it is preferable that the second blades 34 have a structure that allows the crumbs discharged between the stator 38 and the pump casing 24 to be almost completely dispersed by rotating the outer periphery of the stator 38.

  In the present embodiment, since the second blade is formed on the outer peripheral side of the first blade together with the first blade 32, the discharge head of the pump is preferably increased to 10 m or more, more preferably 12 m or more. It is possible to effectively prevent clogging of the rubber-like polymer component inside the pump. In particular, in the present embodiment, since the second blades 34 are provided on the outer periphery of the stator 38, it is possible to effectively prevent crumb clogging in the gap between the stator 38 and the pump casing 24.

  The stator 38 is disposed between the first blade 32 and the second blade 34 so as to cover the first blade 32. The stator 38 has a suction hole 38a on the suction port 26 side and a side surface portion. A through hole 38b is provided. The suction hole 38 a is a through hole for sending the fluid sucked from the suction hole 26 toward the first blade 32. On the other hand, the through hole 38b is a through hole for discharging the crumbs crushed by the first blade 32 and having a size of a certain size or less from the first blade 32 toward the second blade 34. By adjusting the size, the size of the crumb discharged can be controlled. The shape and size of the through-hole 38b are not particularly limited, but it is preferable to adjust the maximum width of the crumbs crushed by the first blade 32 and discharged in the direction of the second blade 34 to 3 to 20 mm. . If the through-hole 38b is too small, the time required for crushing the crumb becomes longer, and the productivity tends to decrease. On the other hand, if it is too large, the crumb may be clogged in the pump 10.

  An adapter 40 is attached to the suction port 26. The adapter 40 is formed with a latex transport pipe 42 as a latex feeding means for feeding a polymer latex in a solution state, and a coagulating liquid transport pipe 44 as a coagulating liquid feeding means for feeding a coagulating liquid containing a coagulant. It is.

  The latex transport pipe 42 directly transports the polymer latex containing the rubber-like polymer polymerized in the polymerization tank or the like to the suction port 26 of the pump 10. A transportation pump is disposed in the middle of the pipe 42.

  The coagulation liquid transported by the coagulation liquid transport pipe 44 is a mixed solution of a coagulant such as calcium chloride and water, and the concentration of the coagulant in the coagulation liquid is 5 to 35% by weight with respect to the entire coagulation liquid. To the extent. The supply amount of the coagulation liquid is not particularly limited, but is preferably about 0.5 to 20 parts by weight with respect to 100 parts by weight of the polymer latex. When the supply amount of the coagulating liquid is too small, the precipitation of the rubber-like polymer component in the pump 10 tends to be insufficient. Further, when the supply amount of the coagulating liquid is too large, it tends to be difficult to remove the coagulant in the cleaning process.

  The adapter 40 is in contact with the polymer latex and the coagulating liquid sent by the latex transporting pipe 42 and the coagulating liquid transporting pipe 44 before being mixed by the first blade 32 and the second blade 34, respectively. It is inserted into the suction port 26.

  In the present embodiment, the polymer latex and the coagulation liquid are separately supplied through the suction port 26 via the latex transport pipe 42 and the coagulation liquid transport pipe 44, respectively, in front of the flow direction of the first blade 32, The polymer latex and the coagulating liquid are brought into contact with each other in the flow direction of the first blade 32. For this reason, the rubber-like polymer is coagulated in the vicinity of the first blade 32, and the solidified rubber-like polymer is suitable for being crushed and dispersed by the first blade 32 and the second blade 34 and transported. A slurry (crumb slurry) containing a rubber-like polymer crumb having a large size is discharged from the discharge port 28.

  In this embodiment, in addition to the polymer latex and the coagulation liquid, 0 to 95 ° C. dilution water can be used as necessary. As the dilution water, overflow water from the tank 18 described later is used. It is preferable to use cleaning wastewater collected in the cleaning step. The dilution water is put into the pump 10 with a crushing function in a state of being mixed with polymer latex or coagulation liquid in advance.

  As shown in FIGS. 2 and 3, the pump 10 has a discharge port 28 for discharging the crumb slurry upward, and an inner diameter (diameter) D of the discharge port 28 is 50 to 200 mm. Is preferred. As shown in FIG. 3, a slurry supply pipe 46 is connected to the discharge port 28, and the crumb slurry discharged from the discharge port 28 is once released into the atmosphere through the slurry supply pipe 46. Then, it is made to collide with the side wall 50 formed at the connecting portion between the slurry supply pipe 46 and the stirring device 12, falls, and is supplied into the tank 18. The slurry supply pipe 46 has a pipe length L that is the length from the discharge port 28 of the pump 10 to the open portion, and this pipe length L is the sum of L1 and L2 shown in FIG. L = L1 + L2), and L = about 200 to 2000 mm. However, depending on the arrangement, such as when the pump can be installed sideways or when the pump outlet is installed in the pump casing lateral direction or lateral tangential direction, the piping length L is 0, that is, the piping The pump discharge port may be directly connected to the stirring device 12 without being interposed. Further, the length ratio between L1 and L2 in FIG. 3 is not particularly limited, and can be appropriately adjusted according to the installation space of the equipment.

  In the present embodiment, the ratio (L / D) between the inner diameter D of the discharge port 28 and the length L of the slurry supply pipe 46 is preferably 20 or less, more preferably 18 or less. By effectively setting the ratio (L / D) of the inner diameter D of the discharge port 28 to the length L of the slurry supply pipe 46 within the above range, clogging of the rubber-like polymer crumb in the pipe 46 is effectively prevented. As a result, the dispersibility of the rubber-like polymer crumb in the slurry at the time of opening can be improved.

  Next, the crumb slurry released into the atmosphere from the slurry supply pipe 46 is stirred and retained by the stirring device 12. By stirring and retaining the crumb slurry, the contact of the coagulant with the rubber-like polymer component in the crumb slurry can be promoted, and the solidification of the rubber-like polymer component can proceed almost completely.

  As shown in FIG. 4, the stirring device 12 includes a tank 18 and a mixer 20 with a stirring / crushing function including a stirring unit 21 at the bottom of the tank 18. A perspective view and a cross-sectional view of the stirring unit 21 of the mixer 20 with the stirring / crushing function are shown in FIGS. 5 (A) and 5 (B). As shown in FIGS. 5 (A) and 5 (B), the stirring unit 21 is disposed on the outer peripheral side of the plurality of rotary blades 211 formed on the rotary body 214 and the rotary blades 211, and on the side surface portion. And a fixed blade 212 having a plurality of through holes 213. The rotating blade 211 is freely rotatable by a motor (not shown) connected via the rotating shaft 215, and the rotating blade 211 rotates to generate a circulating flow in the crumb slurry. In this embodiment, the rubber-like polymer in the crumb slurry sucked into the rotary blade 211 is crushed by the rotary blade 211 and the fixed blade 212 of the stirring unit 21 by this circulation flow. In the present embodiment, by adjusting the size of the through hole formed in the fixed blade 211, the size of the discharged crumb can be controlled to be constant. The size of the through hole 213 is not particularly limited, but it is preferable to adjust the maximum width of the crumb to be, for example, about 3 to 20 mm. When the crumb diameter becomes too small, the fixed blade 212 may be removed and the crumb may be crushed and dispersed by the crushing effect of the rotary blade 211 alone. Further, the through-hole 213 may be circular as shown in FIG. 5A, or may be rectangular as shown in FIG.

In this embodiment, as the mixer 20 with the stirring / crushing function, the stirring power is 1 kW / m ³ or more, preferably 2 kW / m ³ or more, more preferably 5 kW / m ³ or more, and particularly preferably 15 kW / m ³ or more. Use a mixer that is By using a mixer whose stirring power is in the above range, the contact of the coagulant with the rubbery polymer component can be promoted, and the coagulation of the rubbery polymer component is allowed to proceed almost completely in a short time. be able to. Therefore, the size of the stirring device 12 can be reduced. Specifically, 900～1300Mm the internal diameter _{D M} of the tank 18, even when the height _{H M} of the tank 18 was 1300～2000Mm, a large-sized manufacturing facility that has been used conventionally (conventionally, at least _D M = 3000 mm and H _M = 3000 mm are necessary.) It is possible to ensure the same productivity. Furthermore, by using such a mixer 20 with a stirring and crushing function, adhesion of the rubber-like polymer to the mixer 20 and the side wall of the tank 18 can be effectively prevented. In particular, the use of the stirring device 12 of this embodiment eliminates the need to use equipment such as the coagulation tank 4 having stirring blades as shown in FIG. The adhesion of the rubber-like polymer to the side wall can be prevented.

Moreover, as for the rotation speed of the mixer 20 with a stirring and crushing function, 850-5000 rpm is preferable and it is especially preferable to set it as 900-3500 rpm. By setting the rotation speed in such a range, the stirring power can be set in the above range. In particular, in the solidification tank 4 having a conventional stirring blade, the rotational speed of the stirring blade can be increased only up to about 80 to 100 rpm at the highest because of the structure thereof. It could only be increased to about 6 kW / m ³ . On the other hand, according to the mixer 20 with the stirring / crushing function of the present embodiment, the rotational speed can be increased as described above, and the stirring power can be set within the predetermined range described above.

  Furthermore, in the present embodiment, as shown in FIG. 4, it is preferable to perform steam coagulation by blowing steam from the steam supply pipe 48 into the liquid phase portion of the tank 18. By blowing steam into the liquid phase portion of the tank 18, the contact of the coagulant with the crumb-like rubbery polymer component already coagulated and the rubber-like polymer component remaining in the serum water is promoted. The rubber-like polymer component can be solidified almost completely in a shorter time. Therefore, according to the present embodiment, the solidification of the rubber-like polymer component proceeds almost completely even when the stirring and residence time of the crumb slurry in the stirring device 12 is relatively short as 30 to 180 seconds. Can be made.

  The amount of steam introduced is preferably 15 to 250 parts by weight, more preferably 50 to 200 parts by weight, with respect to 100 parts by weight of the rubber-like polymer supplied. If the amount of steam introduced is too small, the above effect will be difficult to obtain. On the other hand, if the amount is too large, (a) the crumb will be too fine and the vibrating screen will be clogged, or The rate is too high, resulting in poor biting and (c) energy loss due to excessive steam. Further, the temperature of the steam to be introduced may be appropriately determined according to the type of rubber polymer to be produced and the organic solvent to be used, but is preferably 120 to 190 ° C. The pressure is preferably a gauge pressure of 0.1 to 1.2 MPa.

In the present embodiment, the steam supply pipe 48 may be installed at a position where it can be directly blown into the liquid phase part of the tank, and is not particularly limited, but is preferably arranged in the vicinity of the slurry supply pipe 46. Specifically, d _M / D _M = 0.1 to 0.6 in relation to d _M that is the distance between the slurry supply pipe 46 and the steam supply pipe 48 in relation to the inner diameter D _{M of the} tank 18. range or, in relation to the height _{H M} of the tank _18, is preferably in the range of d _M / H _M = 0.1~0.5. In addition, the shape of the nozzle for blowing the steam formed to protrude into the tank 18 is not particularly limited, but in particular, the shape of the tip portion narrowed from the inner diameter of the base end portion is narrowed. Is preferred.

  Next, using the vibrating screen 14, the coagulant adhering to the surface of the crumb-like rubbery polymer is removed to obtain a hydrated crumb. Specifically, washing water is supplied to the crumb slurry with a spray nozzle to remove the coagulant adhering to the surface of the rubber-like polymer, and the liquid and the crumb-like rubber-like polymer are separated from each other on a screen. By doing so, hydrated crumbs are obtained. Various types of spray nozzles can be used as the spray nozzle, and the spray nozzle is not particularly limited.

  By using the vibrating screen 14, the concentration of the coagulant remaining in the crumb is reduced to about 1000 ppm or less. The amount of water used for washing is preferably 1 to 500 parts by weight, more preferably 1 to 100 parts by weight, with respect to 100 parts by weight of the rubber-like polymer. In addition, it is preferable to collect | recover about the washing | cleaning waste_water | drain with a comparatively low coagulant | flocculant density | concentration among washing | cleaning waste_water | drain generate | occur | produced by a washing | cleaning process, and to supply to the pump 10 with a crushing function again as dilution water.

  Subsequently, the squeezer 16 is used to dehydrate the washed hydrated crumb. The squeezer 16 has a rotatable screw 22 inside, and dewatering is performed by squeezing out moisture from the crumb, thereby obtaining a crumb having a moisture content adjusted to about 10% by weight.

  Next, the dehydrated crumb is heat-dried with a band dryer to obtain a crumb that is substantially free of moisture (moisture moisture content is 0.5 wt% or less). The temperature at which the crumb is dried is about 40 to 100 ° C.

  The crumb dried above is discharged, for example, in the form of flakes, then introduced into a baler (not shown), compressed, made into an appropriate size and made into a product (bale).

  In the present embodiment, the rubber-like polymer is coagulated using the pump 10 with a crushing function and the stirring device 12 having the mixer 20 with a stirring / crushing function. This eliminates the need for a coagulation apparatus consisting of a large tank that has been used in the prior art, thereby enabling a reduction in manufacturing processes and manufacturing equipment, thereby reducing equipment costs and manufacturing costs. In this embodiment, the rubbery polymer component can be coagulated at a high crumb concentration, so that the amount of washing water and coagulant used can be reduced. Further, the operation is simplified, the loss of the product is reduced even when the type of the rubbery polymer to be produced is switched, and the switching time can be shortened, so that the operability is improved.

The present invention is not limited to the above-described embodiments, and can be variously modified within the scope of the present invention.
For example, in the above-described embodiment, the mixer 20 with the stirring / crushing function is provided near the bottom of the tank 18, but the mixer 20 with the stirring / crushing function may be provided in the side wall portion of the tank 18. good. Moreover, when introducing steam into the tank 18, it is good also as a structure which introduces steam from several places using several steam supply piping.

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

Example 1
First, an NBR (acrylonitrile-butadiene rubber) latex was prepared as a polymer latex, and an aqueous calcium chloride solution was prepared as a coagulant.
Next, using a NBR latex, a calcium chloride aqueous solution and dilution water, a production apparatus having a pump 10 with a crushing function shown in FIGS. 1 to 4 and a stirring device 12 having a mixer 20 with a stirring / crushing function. Thus, NBR was manufactured. The amounts of NBR latex, calcium chloride aqueous solution and dilution water were adjusted so that the crumb concentration in the entire slurry was 9.1% by weight.

As the pump 10 with a crushing function, a pump in which a second blade 34 was formed on the outer periphery of the first blade 32 as shown in FIG. 2 was used in an Inline Mixer (model 450LS manufactured by Silverson). The pump rotation speed was 3000 rpm, the flow rate was 25 m ³ / h, and the discharge head was 15 m. Also, the inner diameter (D) of the discharge port 28 of the pump 10 shown in FIG. 3 and the pipe length (L = L1 + L2) from the discharge port 28 to the open portion of the slurry supply pipe 46 are D = 48 mm, L = 800 mm, L / D = 16.67 mm.

Further, a bottom mixer (Silverson model BE275) is used as the mixer 20 with stirring and crushing function constituting the stirring device 12, and a 70L tank (tank inner diameter D _M = 400 mm, tank height) is used as the tank 18. It is using the _H M = 670mm). The rotation speed of the mixer 20 with the stirring / crushing function was set to 3000 rpm, and steam was blown from the steam supply pipe 48 under the condition of 160 parts by weight with respect to 100 parts by weight of rubber. The distance d _M between the slurry supply pipe 46 and the steam supply pipe 48 was 200 mm.

Reference example 1
NBR was produced in the same manner as in Example 1 except that the amount of steam blown was 10 parts by weight with respect to 100 parts by weight of rubber.

Comparative Example 1
NBR was produced in the same manner as in Example 1 except that the rotation speed of the mixer 20 with the stirring and crushing function was 800 rpm.

Comparative Example 2
NBR was produced in the same manner as in Example 1 except that the coagulation tank 4 having the stirring blades shown in FIG. 7 was used instead of the stirring device 12 shown in FIG. In Comparative Example 2, the rotation speed of the stirring blade was 80 rpm.

表１において、クラム分散性については、タンク内で、クラム同士の付着等がなく分散している場合を良好とした。
また、セラム水の白濁の有無は、撹拌装置にて撹拌した後のセラム水を透明な容器に採取し、目視観察することにより評価した。具体的には、以下の基準で評価した。
○ … セラム水が透明である
△ … セラム水が若干白濁している
× … セラム水が完全に白濁している
セラム水が透明（白濁がない）な場合は凝固が完結しており、凝固性は良好であると評価でき、一方、セラム水が白濁している場合は、セラム水中にゴム重合体成分が残留しており、凝固性は不十分であると評価できる。
なお、実施例１、参考例１、比較例１，２のいずれも、撹拌装置で撹拌する前の（すなわち、ポンプから吐出した後の）クラムスラリーにおけるセラム水は、白濁していた。

In Table 1, regarding the crumb dispersibility, the case where the crumbs were dispersed without any adhesion between crumbs in the tank was considered good.
Further, the presence or absence of white turbidity of the serum water was evaluated by collecting the serum water after stirring with a stirrer in a transparent container and visually observing it. Specifically, evaluation was performed according to the following criteria.
○… Serum water is transparent △… Serum water is slightly cloudy ×… Serum water is completely cloudy If the serum water is transparent (no cloudiness), coagulation is complete and solidification On the other hand, when the serum water is cloudy, it can be evaluated that the rubber polymer component remains in the serum water and the coagulation property is insufficient.
In all of Example 1, Reference Example 1, and Comparative Examples 1 and 2, the serum water in the crumb slurry before being stirred by the stirring device (that is, after being discharged from the pump) was cloudy.

From Evaluation Table 1, in Example 1 and Reference Example 1 where the stirring power was 15.7 kW / m ³ , the residence time (treatment time) in the stirring device 12 was a relatively short time of 105 seconds. Nevertheless, the crumbs did not adhere to each other, and the dispersibility of the crumbs after stirring and staying could be improved. In particular, in Example 1 in which the stirring power is within the range of the present invention, and steam is blown into the tank 18 constituting the stirring device 12 at a ratio of 160 parts by weight with respect to 100 parts by weight of the rubber, steam coagulation is performed. As a result, the white turbidity of the serum water disappeared and it was completely solidified.

On the other hand, in Comparative Example 1, as a result of setting the rotation speed to 800 rpm, the stirring power was as low as 0.4 kW / m ³ , and the crumbs adhered to each other, resulting in poor crumb dispersibility. Moreover, in Comparative Example 1, although the amount of steam blown was the same as in Example 1, the serum water became cloudy. The reason for this is that since the stirring power is reduced, the circulation flow of the crumb slurry is weakened. As a result, the effect of steam coagulation, that is, the effect of adhesion of the coagulant to the rubber polymer component in the crumb slurry becomes insufficient. It is thought that

Further, in Comparative Example 2 in which the crumb slurry was stirred and retained using the conventional coagulation tank 4 having stirring blades, the stirring power was as low as 0.4 kW / m ³ and the crumb dispersibility was poor. Met. In particular, in Comparative Example 2, a large amount of the rubber-like polymer adhered to the stirring blade and the wall surface of the tank. In the solidification tank 4 having a conventional stirring blade, the stirring power could only be increased to about 0.6 kW / m ^{3 due} to the characteristics of the apparatus.

FIG. 1 is a schematic view of an apparatus for producing a rubbery polymer according to an embodiment of the present invention. FIG. 2 is a cross-sectional view of a main part of a pump with a crushing function according to an embodiment of the present invention. FIG. 3 is a schematic view showing a part of an apparatus for producing a rubbery polymer according to an embodiment of the present invention. FIG. 4 is a cross-sectional view of a main part of a stirring device having a stirring and crushing function according to an embodiment of the present invention. FIG. 5 (A) is a perspective view of the agitation unit of the mixer with agitation / crushing function according to one embodiment of the present invention, and FIG. 5 (B) is the agitation unit of the mixer with agitation / crushing function according to one embodiment of the present invention. FIG. FIG. 6 is a perspective view of a stirring unit of a mixer with a stirring / crushing function according to another embodiment of the present invention. FIG. 7 is a schematic view of an apparatus for producing a rubbery polymer according to a conventional example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Pump with crushing function 12 ... Stirrer 14 ... Vibrating screen 16 ... Squeezer 18 ... Tank 20 ... Mixer with stirring / crushing function 21 ... Stirring part 211 ... Rotary blade 212 ... Fixed blade 213 ... Through hole 214 ... Rotating body 215 Rotating shaft 22 ... Screw 24 ... Pump casing 26 ... Suction port 28 ... Discharge port 30 ... Rotating body 32 ... First blade 34 ... Second blade 36 ... Rotating shaft 38 ... Stator 40 ... Adapter 42 ... Latex transport piping 44 ... Solidification Liquid transport pipe 46 ... Slurry supply pipe 48 ... Steam supply pipe 50 ... Side wall

Claims (9)

Contacting the polymer latex with a coagulating liquid containing a coagulant to coagulate the rubbery polymer component to obtain a crumb slurry containing a crumb-like rubbery polymer;
The crumb slurry is discharged into a tank having a mixer with a stirring / crushing function whose stirring power is 1 kW / m ³ or more, and in the tank, the rubber-like polymer contained in the crumb slurry is discharged by the mixer. A step of stirring and crushing;
I have a,
A method for producing a rubber-like polymer , wherein the agitation / crushing part of the mixer with agitation / crushing function is formed on the side wall or bottom of the tank . When the rubber-like polymer contained in the crumb slurry is stirred and crushed in the tank having the mixer with the stirring / crushing function, the supply amount of the rubber-like polymer to the liquid phase portion in the tank The method for producing a rubber-like polymer according to claim 1 , wherein 15 to 250 parts by weight of steam is blown into 100 parts by weight. The rubber-like polymer according to claim 1 or 2 , wherein the polymer latex and the coagulation liquid are supplied to a pump having a crushing function, and the polymer latex and the coagulation liquid are brought into contact with each other inside the pump. Production method. A pump having the crushing function, a first blade for crushing the solidified rubbery polymer component;
A second wing provided on an outer periphery of the first wing;
A through-hole disposed between the first blade and the second blade for discharging the rubber-like polymer component crushed by the first blade from the first blade toward the second blade. Having a fixed frame;
The method for producing a rubbery polymer according to claim 3 , comprising: The crumb slurry is further released to the atmosphere through a pipe from the discharge port of the pump with the crushing function, and then the crumb slurry released to the atmosphere is further discharged to the tank,
The method for producing a rubber-like polymer according to claim 3 or 4 , wherein a ratio (L / D) between the length L of the pipe and the inner diameter D of the discharge port of the pump with the crushing function is 20 or less. The crumb slurry was stirred and crushed by the stirring and crushing function mixer, by washing with water, according to claim 5 having a cleaning process for removing the coagulant from the crumb rubber-like polymer, further A method for producing a rubbery polymer according to any one of the above. A dehydration step of removing water from the crumb slurry stirred and crushed by the mixer with the stirring and crushing function to obtain a crumb-like rubber polymer;
The method for producing a rubbery polymer according to any one of claims 1 to 6 , further comprising a step of heating and drying the crumb-like rubbery polymer from which water has been removed. The method for producing a rubbery polymer according to any one of claims 1 to 7 , wherein the polymer latex is a latex of an unsaturated nitrile-conjugated diene copolymer obtained by emulsion polymerization. The method for producing a rubbery polymer according to any one of claims 1 to 8 , wherein the coagulant is at least one selected from the group consisting of calcium chloride, magnesium sulfate, and aluminum sulfate.

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