JP7287191B2 - Synthetic rubber manufacturing method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing synthetic rubber, and more particularly to a method for producing synthetic rubber suitable for producing acrylic rubber sheets and veils.

Synthetic rubber, such as acrylic rubber, is a polymer whose main component is acrylic acid ester, and is generally known as a rubber with excellent heat resistance, oil resistance, and ozone resistance, and is widely used in automobile-related fields. .

Such synthetic rubbers are usually prepared by emulsion polymerization of monomer components constituting the rubber, bringing the obtained emulsion polymerization solution into contact with a coagulant, drying the resulting water-containing crumbs to a predetermined water content or less, and then baling them. It is shipped as a product in a state of being made.

As a conventional method for producing this type of synthetic rubber, for example, in Patent Document 1, in order to cut out a cut sheet-shaped rubber of a predetermined length from a continuous sheet having adhesiveness, cutting is performed above and below a predetermined conveying position of a roller conveyor. It is disclosed that a blade and a blade receiver are provided, and a rubber sheet is cut while being sandwiched between the cutting blade and the blade receiver.

Further, in Patent Document 2, among a plurality of conveyors that convey sheet-like unvulcanized rubber continuously supplied from an unvulcanized rubber supply device, a cutter is arranged at the upper end of the conveyor on the upstream side, A movement distance sensor for measuring the movement distance of the rubber sheet is arranged at the upstream end of the conveyor, and a rubber bale of a specified weight range is cut out for each predetermined movement distance of the continuously supplied rubber sheet. there is

JP-A-3-117595 JP-A-6-201440

However, in the conventional method of manufacturing synthetic rubber as described above, when the cutting blade descends so as to cut into the upper surface of the rubber sheet, the cutting force changes greatly in the middle of the descent of the cutting blade and the rubber sheet bends, resulting in the cut surface. There is a possibility that the rubber sheet will be tilted or twisted or the rubber sheet will be misaligned.

On the other hand, it is conceivable to stop the transportation of the front end portion of the synthetic rubber sheet to be cut into a cut sheet of a predetermined length when the cut sheet is cut, but simply stop the transportation of the front end portion. However, there remains the problem that distortion in the conveying direction is likely to occur on the upstream side (upstream side), and that the surface of the synthetic rubber sheet cut by the cutting blade is likely to be inclined or twisted.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to realize a synthetic rubber manufacturing method capable of effectively suppressing tilting and twisting of a cut surface of a rubber sheet and obtaining a good cut surface.

In order to achieve the above object, the method for producing a synthetic rubber of the present invention comprises a coagulation step of supplying a polymer latex, a coagulant and water into a coagulation tank at a set temperature and agitating them to produce water-containing crumbs; and washing water are supplied to a washing tank and stirred to wash the water-containing crumbs, and the water-containing crumbs after washing are supplied to the material supply zone of an extrusion dryer, and compressed and dehydrated by the extrusion dryer, Extrusion drying process in which moisture is evaporated by heating and kneading, and synthetic rubber with a water content below a predetermined level is extruded into a sheet form. Conveyance cooling in which the extruded sheet-shaped synthetic rubber is conveyed on a conveyor and cooled to a predetermined cooling temperature. a step of intermittently conveying the sheet-like synthetic rubber cooled to the predetermined cooling temperature on the downstream side in the conveying direction, and speed absorption for absorbing the conveying speed difference of the sheet-like synthetic rubber on the upstream side of the intermittent conveying section; and a cutting step of setting a region and cutting the front end portion of the sheet-like synthetic rubber in a stopped state into cut sheets of a predetermined length with a cutting blade.

With this configuration, in the present invention, when the sheet-shaped synthetic rubber stops due to intermittent transportation on the downstream side in the transportation direction, the speed difference between the intermittent transportation section and the transportation section on the upstream side is used to determine the transportation of the sheet-shaped synthetic rubber. It can be absorbed by the change in posture, and it is possible to prevent unnecessary force from acting on the front end portion of the sheet-shaped synthetic rubber in the stopped state. Therefore, tilting and twisting of the cut surface of the rubber sheet during the cut sheet cutting process can be effectively suppressed, and stable cutting can be performed to obtain a good cut surface.

In the synthetic rubber manufacturing method of the present invention, a registration roller (pressing roller for registering the cutting position and a driving roller) is provided in front of a predetermined conveying position where the sheet-like synthetic rubber is cut by the cutting blade. Note) is characterized in that the sheet-shaped synthetic rubber is repeatedly conveyed and conveyed at predetermined timings.

In this case, it becomes possible to control the length of the sheet-like synthetic rubber supplied to the predetermined conveying position where the sheet-like synthetic rubber is cut by the cutting blade.

In the synthetic rubber manufacturing method of the present invention, the conveying speed V of the sheet-shaped synthetic rubber in the conveying and cooling step, the conveying operation time T1 during which the registration rollers convey the sheet-shaped synthetic rubber, and the registration rollers V=V1×T1/(T1+T2, where V=V1×T1/(T1+T2 ) can be set so as to satisfy the expression

In this manner, the sheet-like synthetic rubber can be supplied at an appropriate timing to the predetermined transfer position where the sheet-like synthetic rubber is cut by the cutting blade according to the transfer speed of the sheet-like synthetic rubber in the transfer cooling step. Thus, a series of processes can be performed continuously for a long time while preventing abnormal bending and abnormal tension of the sheet-like synthetic rubber. Here, the conveying speed is the tip speed of the sheet-shaped synthetic rubber extruded from the extrusion dryer, and is approximately the same value as the extrusion speed, and the average conveying speed is the average value of the conveying speed of the registration rollers during the conveying operation time. .

In the synthetic rubber manufacturing method of the present invention, when the cut sheet-like synthetic rubber has a predetermined length L, it may be set so as to satisfy the formula of L=V1×T1. In this case, the transfer speed or transfer operation time of the synthetic rubber sheet by the registration rollers can be set according to the predetermined length of the synthetic rubber cut sheet.

In the synthetic rubber manufacturing method of the present invention, the weight of the cut sheet-shaped synthetic rubber is measured, and the cut sheet-shaped synthetic rubber is measured according to the deviation of the measured weight value from the specified weight value. The predetermined length L can be adjusted. In this case, the synthetic rubber bale can be manufactured efficiently while suppressing weight variations.

In the synthetic rubber manufacturing method of the present invention, it is preferable that a deflection allowance section for allowing deflection of the sheet-shaped synthetic rubber in the conveying direction is provided in front of the registration rollers. By doing so, the bending of the sheet-like synthetic rubber is allowed at the front stage of the registration rollers, and the registration rollers can temporarily stop the conveying operation.

In the synthetic rubber manufacturing method of the present invention, the synthetic rubber may be an acrylic rubber. In this case, synthetic rubber suitable for various rubber products requiring oil resistance at high temperatures can be efficiently produced.

ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the synthetic rubber which can suppress the inclination and twist of the cut surface of a rubber sheet effectively, and can obtain a favorable cut surface can be implement|achieved.

1 is a schematic configuration diagram of a synthetic rubber production system according to one embodiment of the present invention; FIG. It is a figure which shows the conveyance type cooling device and cutting device in the synthetic rubber manufacturing system which concerns on one Embodiment of this invention. FIG. 4 is an explanatory diagram of a deflection allowance part, which is a part of the transport-type cooling device in the synthetic rubber manufacturing system according to one embodiment of the present invention; BRIEF DESCRIPTION OF THE DRAWINGS It is a flowchart which shows the outline|summary procedure of the synthetic-rubber manufacturing method which concerns on one Embodiment of this invention.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the drawings.

First, a synthetic rubber manufacturing system according to an embodiment of the present invention that can be used for manufacturing synthetic rubber will be described.

The synthetic rubber production system according to the present embodiment can be suitably used, for example, in the production of acrylic rubber. In the following, acrylic rubber will be described as an example, but the same applies to the production of synthetic rubbers other than acrylic rubber. can be used for

Other synthetic rubbers include, for example, styrene-butadiene rubber (SBR), butadiene rubber (BR), isoprene rubber (IR), styrene-isoprene block polymer (SIS), styrene-butadiene block polymer (SBS), nitrile butadiene rubber. (NBR), chloroprene rubber (CR), butyl rubber (IIR), ethylene-propylene-diene terpolymer rubber (EPDM), chlorosulfonated polyethylene rubber, olefinic rubber such as fluororubber, silicone rubber, urethane rubber and the like.

As shown in FIG. 1, the synthetic rubber production system 1 according to the present embodiment includes an emulsion polymerization device, a coagulation device 3, a cleaning device 4, a screw-type extrusion dryer 5, a conveying cooling device 6, and a cutting device 7 (not shown). , and a baling device 8 . The screw-type extrusion dryer 5 of this embodiment corresponds to the extrusion dryer of the present invention. Further, as will be described later in detail, the synthetic rubber manufacturing method according to the embodiment of the present invention includes an emulsion polymerization process, a coagulation process, a washing process, an extrusion drying process, a transport cooling process, a cutting process, and a bale process. contains. Each of the devices used in these steps will be described below.

[Emulsion polymerization device]
An emulsion polymerization apparatus (not shown) is an apparatus used for processing related to the emulsion polymerization step in the synthetic rubber manufacturing method according to the present embodiment. Specifically, the emulsion polymerization apparatus mixes water and an emulsifier with a monomer component for forming an acrylic rubber in a reactor, emulsifies while appropriately stirring with a stirrer, and in the presence of a polymerization catalyst. An emulsion polymerization liquid is obtained by emulsion polymerization. The reactor of the emulsion polymerization apparatus according to the present embodiment is a continuous type in which the charging of raw materials into the reactor, the reaction, and the recovery of the product are all performed at the same time. good. Further, the reactor of the emulsion polymerization apparatus according to the present embodiment is a tank reactor, but may be a tubular reactor.

[Coagulation device]
The coagulating device 3 is a device used for processing related to the coagulating step in the synthetic rubber manufacturing method according to the present embodiment. Specifically, the coagulation device 3 is adapted to bring the emulsion polymerization liquid obtained in the emulsion polymerization device into contact with a coagulation liquid as a coagulant to coagulate the water-containing crumbs. As shown in FIG. 2, the coagulation apparatus 3 according to the present embodiment includes a coagulation tank 30 containing the emulsion polymerization liquid and the coagulation liquid obtained by the emulsion polymerization apparatus, and heats the inside of the coagulation tank 30 and maintains a desired temperature. A heating device 31 for heating and a stirring device 34 for stirring the emulsion polymerization liquid and the coagulation liquid contained in the coagulation tank 30 are provided.

The coagulation tank 30 is composed of, for example, a closed bottom and a cylindrical side wall, and is capable of storing the emulsion polymerization liquid and the coagulation liquid. The heating device 31 includes a heating section 32 that heats the inside of the solidification tank 30 and a temperature control section (not shown) that controls the temperature inside the solidification tank 30 . The stirring device 34 includes a stirring blade 35 which is a member which is arranged in the coagulation tank 30 and rotates around a predetermined axis, a motor 36 which rotates the stirring blade 35, and a rotation speed and rotation speed of the stirring blade 35 (not shown). drive control unit.

In the coagulation device 3 of the present embodiment, the contact between the emulsion polymerization liquid and the coagulation liquid adopts a method of adding the emulsion polymerization liquid to the coagulation liquid being stirred. That is, the coagulation tank 30 of the coagulation device 3 is filled with a coagulation liquid, and the emulsion polymerization liquid is added to and brought into contact with the coagulation liquid to solidify the emulsion polymerization liquid, thereby producing water-containing crumbs.

The heating device 31 of the coagulation device 3 is configured to heat the coagulation liquid filled in the coagulation tank 30 . Specifically, the heating device 31 sends steam to a jacket serving as a heating unit 32 provided on the outer periphery of the coagulation tank 30, and heat is exchanged between the steam and the coagulation tank 30 or the coagulation liquid in the coagulation tank 30. The coagulation liquid is heated.

The temperature control unit of the solidification device 3 is configured to control the temperature in the solidification tank 30 by controlling the heating operation of the heating unit 32 while monitoring the temperature in the solidification tank 30 measured by the thermometer. ing. The temperature of the coagulation liquid in the coagulation bath 30 is controlled by the temperature control section to be generally 40°C or higher, preferably 40 to 90°C, more preferably 50 to 80°C.

In order to control the temperature of the liquid phase in the coagulation tank 30 to a set temperature, for example, a control system for controlling the temperature and flow rate of steam that heats the coagulation tank 30, and the hot water supplied to the coagulation tank 30. A liquid phase temperature control system of a cascade control method may be configured in which the other control system for controlling the temperature is also used.

The stirring device 34 of the coagulation device 3 is configured to stir the coagulation liquid filled in the coagulation tank 30 . Specifically, the stirring device 34 includes a motor 36 that generates rotational power and stirring blades 35 that extend in a direction perpendicular to the rotating shaft of the motor 36 . The stirring impeller 35 rotates around a rotating shaft by the rotational power of the motor 36 in the coagulation liquid filled in the coagulation tank 30 to cause the coagulation liquid to flow. The shape, size, and number of the stirring blades 35 are appropriately determined in consideration of the required strength of stirring.

The drive control section of the coagulation device 3 is configured to control the rotational drive of the motor 36 of the stirring device 34 to set the rotational speed and rotational speed of the stirring blades 35 of the stirring device 34 to predetermined values. The rotation of the stirring blades 35 is controlled by the drive control unit so that the stirring speed of the coagulated liquid is usually 100 rpm or more, preferably 200 to 1000 rpm, more preferably 300 to 900 rpm, and particularly preferably 400 to 800 rpm. be done. The peripheral speed of the coagulation liquid is usually 0.5 m/s or higher, preferably 1 m/s or higher, more preferably 1.5 m/s or higher, particularly preferably 2 m/s or higher, and most preferably 2.5 m/s or higher. Rotation of the stirring blade 35 is controlled by the drive control unit so that Furthermore, the driving control unit stirs so that the upper limit of the peripheral speed of the coagulation liquid is usually 50 m/s or less, preferably 30 m/s or less, more preferably 25 m/s or less, and most preferably 20 m/s or less. Rotation of wings 35 is controlled.

The coagulation device 3 overflows the produced water-containing crumbs together with hot water from the coagulation tank 30, takes them out of the coagulation tank 30, and supplies them to the cleaning device 4 which performs the cleaning process. Between the coagulation device 3 and the washing device 4 there is arranged a drainer 39 capable of separating free water from the wet crumbs, through which the wet crumbs are fed to the washing device 4. It's like The water separated by the drainer 39 is collected in the tank. The water stored in the tank is pumped to the coagulation tank 30 and reused.

[Washing equipment]
The cleaning device 4 is a device used for processing related to the cleaning step in the synthetic rubber manufacturing method according to the present embodiment. Specifically, the washing device 4 is adapted to wash the water-containing crumbs produced by the coagulating device 3 with washing water. As shown in FIG. 1, the cleaning apparatus 4 according to the present embodiment includes a cleaning tank 40 containing the water-containing crumbs produced by the coagulating apparatus 3 and cleaning water, and heats the interior of the cleaning tank 40 and maintains a desired temperature. A heating device 41 and a stirring device 44 for stirring the wet crumbs contained in the washing tank 40 and the washing water are provided.

The washing tank 40 is composed of, for example, a closed bottom and a cylindrical side wall, and is capable of storing wet crumbs and washing water. The heating device 41 includes a heating unit 42 that heats the inside of the cleaning tank 40 and a temperature control unit (not shown) that controls the temperature inside the cleaning tank 40 . The stirring device 44 includes a stirring blade 45 which is a member that is arranged in the cleaning tank 40 and rotates around a predetermined axis, a motor 46 that rotates the stirring blade 45, and a rotation speed and rotation speed of the stirring blade 45 (not shown). drive control unit. In the washing device 4, the water-containing crumbs produced in the coagulating device 3 are mixed with a large amount of water and washed to effectively reduce the amount of ash in the finally obtained acrylic rubber sheet or acrylic rubber veil. can be done.

The heating device 41 of the cleaning device 4 is configured to heat the inside of the cleaning tank 40 . Further, the temperature control unit of the cleaning device 4 controls the heating operation of the heating unit 42 while monitoring the temperature in the cleaning tank 40 measured by the thermometer, thereby controlling the temperature in the cleaning tank 40. It is configured. As described above, the temperature of the washing water in the washing tank 40 is usually controlled to be 40°C or higher, preferably 40 to 100°C, more preferably 50 to 90°C, and most preferably 60 to 80°C. be.

The washing device 4 overflows the washed wet crumbs together with the washing water from the washing tank 40 to take them out of the washing tank 40, and supplies them to the screw-type extrusion dryer 5 that performs the dehydration process and the drying process. . A drainer 49 capable of separating free water from the washed wet crumbs is arranged between the washing device 4 and the screw-type extrusion dryer 5, and the wet crumbs pass through the drainer 49 to the screw. It is supplied to the die extrusion dryer 5 . A screen is used for the water drainer 49 of the present embodiment, but a wire mesh, an electric sieve, or the like can also be used. Free water separated by the drainer 49 is collected in a tank (not shown). The water stored in the tank is pumped to the coagulation tank 30 and reused.

When the washed wet crumbs are supplied to the screw-type extrusion dryer 5, the temperature of the wet crumbs is preferably 40°C or higher, more preferably 60°C or higher. For example, by setting the temperature of the water used for washing in the washing device 4 to 40° C. or higher, preferably 60° C. or higher (for example, 70° C.), the temperature of the water-containing crumbs when supplied to the screw-type extruder dryer 5 is reduced to It may be possible to maintain the temperature at 40° C. or higher, preferably 60° C. or higher, and the temperature of the water-containing crumb is 40° C. or higher, preferably 60° C. or higher when conveyed from the washing device 4 to the screw-type extruder dryer 5. It may be heated to As a result, dehydration in the subsequent dehydration step and drying in the drying step can be effectively performed, and the moisture content of the finally obtained dry rubber can be significantly reduced.

[Screw type extrusion dryer]
The screw-type extrusion dryer 5 is a device used for processing related to the extrusion drying process (dehydration process and drying process) in the synthetic rubber manufacturing method according to the present embodiment. Specifically, the screw-type extrusion dryer 5 dehydrates the wet crumbs washed by the washing device 4 using a dewatering slit, and dries the dehydrated wet crumbs to obtain dry rubber having a predetermined water content or less. It's becoming Further, the screw-type extrusion dryer 5 is configured to mold the dried rubber obtained by the dehydration process and the drying process into a predetermined shape and discharge it.

Specifically, the screw-type extrusion dryer 5 includes a dehydrating barrel portion functioning as a dehydrator for dehydrating the wet crumbs washed by the washing device 4, and a dryer functioning as a dryer for drying the wet crumbs. A barrel portion and a die portion 11 having a forming function of forming a wet crumb on the downstream side of the screw type extrusion dryer 5 are provided.

Although the screw-type extrusion dryer 5 is used in the present embodiment, a centrifugal separator, a squeezer, or the like may be used as the dehydrator for performing the dehydration process. A hot air drier, a reduced pressure drier, an expander drier, a kneader type drier, or the like may be used as the dryer. Below, a screw type extrusion dryer may be called an extrusion dryer.

Here, an example of operating conditions of the screw-type extruder dryer 5 according to this embodiment will be given.

The rotation speed (N) of the pair of screws in the barrel unit may be appropriately selected according to various conditions, and is usually 10 to 1000 rpm, from the viewpoint of efficiently reducing the water content and gel amount of the acrylic rubber. , preferably 50-750 rpm, more preferably 100-500 rpm, most preferably 120-300 rpm.

The extrusion rate (Q) of the acrylic rubber is not particularly limited, but is usually 100 to 1500 kg/hr, preferably 300 to 1200 kg/hr, more preferably 400 to 1000 kg/hr, and more preferably 500 to 800 kg/hr. Most preferred.

The ratio (Q/N) between the extrusion rate (Q) of the acrylic rubber and the number of revolutions (N) of the screw is not particularly limited, but is usually 1 to 20, preferably 2 to 10, more preferably 3 to 8, with 4 to 6 being particularly preferred.

[Conveyor type cooling device]
The transport-type cooling device 6 is a device used for processing related to the transport cooling step in the synthetic rubber manufacturing method according to the present embodiment. Specifically, the conveying cooling device 6 is a device used for cooling the dried rubber obtained by the screw-type extrusion dryer 5 . As shown in FIG. 2, the conveying-type cooling device 6 according to the present embodiment conveys the sheet-like synthetic rubber 15 extruded from the die part 11 of the screw-type extrusion dryer 5 by the conveyer 61, and cools the cooling means. By blowing cooling air from 65, it cools down to a predetermined cooling temperature. The conveying type cooling device 6 has a structure in which a conveyer 61 for conveying the sheet-like synthetic rubber 15 and a cooling means 65 for sending cooling air are arranged in a cooling tank 66 .

More specifically, the conveyor 61 conveys the sheet-like synthetic rubber 15 discharged from the die part 11 of the screw-type extrusion dryer 5 in the direction of arrow A in FIG. The conveyor 61 has rollers 62 and 63 and a conveyor belt 64 wound around the rollers 62 and 63 and on which the sheet-like synthetic rubber 15 is placed. The conveyor 61 is configured to continuously convey the sheet-like synthetic rubber 15 discharged from the die portion 11 of the screw-type extrusion dryer 5 onto the conveyor belt 64 to the downstream side.

The cooling means 65 blows cooling air sent from a cooling air generating means (not shown) onto the surface of the sheet-like synthetic rubber 15 on the uppermost conveyor 61 .

The length of the conveyor 61 and the cooling means 65 of the transport-type cooling device 6 (the length of the portion to which the cooling air can be blown) is not particularly limited, but is, for example, 2 to 100 m, preferably 5 to 50 m. In addition, the conveying speed of the sheet-shaped synthetic rubber 15 in the conveying type cooling device 6 is determined by the length of the conveyor 61 and the cooling means 65, It may be appropriately adjusted according to the discharge rate, target cooling rate, cooling time, etc., and is, for example, 10 to 100 m/hr, more preferably 15 to 70 m/hr.

In addition, the transport type cooling device 6 is not particularly limited to a configuration including two conveyors 61, 61 and one cooling means 65 as shown in FIG. It may be configured to have one or three or more corresponding cooling means 65 . In that case, the total length of each of one or more of the conveyors 61 and the cooling means 65 should be within the above range.

The conveying cooling device 6 shown in FIG. 2 is directly connected to the die section 11 of the screw-type extrusion dryer 5 shown in FIG. 1, or installed near the die section 11 for use.

The transport-type cooling device 6 according to the present embodiment is an air-cooling system, but is not limited to this, and various systems including a water-spraying system in which water is sprayed, an immersion system in which water is immersed, and the like can be adopted. be. Alternatively, the dried rubber may be cooled by leaving it at room temperature.

[Cutting device]
The cutting device 7 is configured to perform processing related to the cutting step in the synthetic rubber manufacturing method according to the present embodiment. Specifically, the cutting device 7 is a device used for cutting the sheet-shaped synthetic rubber 15 after cooling. As shown in FIG. 5, the cutting device 7 according to the present embodiment cuts the front end portion of the sheet-like synthetic rubber 15 cooled to a predetermined cooling temperature by the conveying cooling device 6 into a pair of adjacent roller conveyors 74 . The synthetic rubber 16 is cut at a predetermined conveying position between the rollers 75 and 75 to obtain a cut sheet-like synthetic rubber 16 of a predetermined length.

With this configuration, the front end portion of the sheet-shaped synthetic rubber 15 (dry rubber) cooled to a predetermined cooling temperature is cut into cut sheets between the adjacent rollers 75, 75 of the roller conveyor 74. The sheet-shaped synthetic rubber 15 can be cut into a constant size while being stably supported on the roller conveyor 74, and excellent processing stability is achieved.

As shown in FIG. 2, a registration roller 76 and a clamper 77 are provided on the upstream side of the cutting device 7, and a weight measuring device 78 is arranged on the downstream side of the cutting device 7. As shown in FIG. The registration rollers 76 function as pressure rollers and drive rollers for registering the cutting position.

The registration rollers 76 rotate in close contact with the sheet-shaped synthetic rubber 15 on the roller conveyor 74, and based on the amount of rotation, feed from a predetermined conveying position where the sheet-shaped synthetic rubber 15 is cut to the tip of the synthetic rubber. It is designed to measure quantity. Further, the weight measuring instrument 78 measures the weight of the synthetic rubber 16 cut in the form of a cut sheet. Then, the predetermined length L of the cut sheet-shaped synthetic rubber 16 is adjusted according to the deviation of the measured weight value from the specified weight value. With this configuration, variations in the weight of the synthetic rubber 16 in the form of cut sheets can be checked one by one, and variations in manufactured products can be suppressed.

In this embodiment, a clamper 77 provided on the upstream side of the cutting device 7 holds the sheet-like synthetic rubber 15 on the roller conveyor 74 when cutting the sheet-like synthetic rubber 15 . . With this configuration, the cooled sheet-like synthetic rubber 15 can be stably supported on the roller conveyor 74 and held by the clamper 77 for cutting, so that processing stability is further improved.

In this embodiment, the sheet-shaped synthetic rubber 15 cooled to a predetermined cooling temperature is intermittently conveyed downstream in the conveying direction, and the sheet-shaped synthetic rubber 15 is intermittently conveyed upstream of the intermittent conveying section (deflection allowance portion 79 in FIG. 5). The conveying height of the synthetic rubber 15 is changed, and the front end portion of the sheet-like synthetic rubber 15 in the stopped state is cut into cut sheets of a predetermined length by the cutting blade 70 . With this configuration, when the sheet-shaped synthetic rubber 15 stops due to intermittent transportation on the downstream side in the transportation direction, the speed difference between the intermittent transportation section and the transportation section on the upstream side is used as the transportation attitude change of the sheet-shaped synthetic rubber 15 . , it is possible to prevent excessive force from acting on the front end portion of the sheet-like synthetic rubber 15 in the stopped state. Therefore, tilting and twisting of the cut surface of the rubber sheet during the cut sheet cutting process can be effectively suppressed, and stable cutting can be performed to obtain a good cut surface.

In this embodiment, a roller conveyor 74 or a registration roller 76 provided upstream of a predetermined conveying position where the sheet-like synthetic rubber 15 is cut by the cutting blade 70 conveys and stops conveying the sheet-like synthetic rubber 15 . It is designed to be repeated at a predetermined timing. This makes it possible to control the length of the sheet-like synthetic rubber 15 supplied to the predetermined conveying position where the sheet-like synthetic rubber 15 is cut by the cutting blade 70 .

Since the sheet-like synthetic rubber 15 is extruded from the screw-type extrusion dryer 5 at a constant extrusion speed (conveyance speed), the roller conveyor 74 or the registration roller 76 is not conveying the sheet-like synthetic rubber 15 during the conveyance stop time. When the conveyance is stopped, the sheet-like synthetic rubber 15 is temporarily bent. Therefore, as shown in FIGS. 2 and 3, a deflection allowance portion 79 is provided on the upstream side of the roller conveyor 74 to allow deflection of the sheet-like synthetic rubber 15 in the conveying direction.

For example, as shown in FIG. 3, the bending allowance portion 79 allows bending of the sheet-shaped synthetic rubber 15 by loosening the sheet-shaped synthetic rubber 15, thereby allowing the roller conveyor 74 or the registration rollers to move. 76 can temporarily stop the transport operation. A container 179 may be provided in the lower portion of the bending-allowing portion 79 so that the sheet-like synthetic rubber 15 can be safely accommodated even if it bends excessively.

[Bale forming device]
The baling device 8 is a device used in the baling step in the synthetic rubber manufacturing method according to the present embodiment. Specifically, the baling device 8 is adapted to process the dried rubber extruded from the screw-type extruder dryer 5 into bales, which are one-piece blocks.

The baling device 8 according to the present embodiment is configured to be capable of manufacturing a synthetic rubber veil 83, which is a single block, by laminating cut sheet-like synthetic rubber 16 cut by the cutting device 7, for example. ing. The baling device 8 sequentially stacks the cut sheet-shaped synthetic rubber 16 cut by the cutting device 7 on the downstream side of the roller conveyor 74 until it reaches a predetermined thickness or weight to form a block of synthetic rubber. A rubber veil 83 is manufactured. As a result, the synthetic rubber veil 83, which is easy to handle and to process such as cutting, can be efficiently manufactured.

Although the weight and shape of the synthetic rubber veil 83 manufactured by the bale forming device 8 are not particularly limited, for example, a substantially rectangular parallelepiped synthetic rubber veil 83 weighing about 20 kg is manufactured.

In this embodiment, the sheet is extruded by the screw-type extrusion dryer 5 to sufficiently reduce the moisture content, and then laminated to form a rubber veil. Compared to , not only is the ease of handling significantly improved, but also the contamination of impurities can be effectively suppressed, and the quality as a material for rubber products can be improved.

When manufacturing an acrylic rubber veil by laminating cut sheet-shaped acrylic rubber, it is preferable to laminate cut sheet-shaped acrylic rubber at 40° C. or higher, for example. By laminating the cut sheet-shaped acrylic rubber at 40°C or higher, good air release is realized by further cooling and compression by its own weight.

<Method for manufacturing synthetic rubber>
Next, a method for manufacturing synthetic rubber such as acrylic rubber using the synthetic rubber manufacturing system 1 described above will be described.

FIG. 4 is a flow chart of a synthetic rubber manufacturing method according to one embodiment of the present invention. As shown in FIG. 4, the synthetic rubber manufacturing method according to the present embodiment includes an emulsion polymerization step S1, a solidification step S2, a washing step S3, an extrusion drying step S4, a conveying cooling step S5, a cutting step S6, and a bale forming step S7. contains. Each step will be described below.

[Emulsion polymerization step]
In the emulsion polymerization step S1, in an emulsion polymerization apparatus, a monomer component for forming a synthetic rubber is mixed with water and an emulsifier, emulsified while appropriately stirred with a stirrer, and emulsion polymerized in the presence of a polymerization catalyst. Thus, an emulsion polymerization liquid (polymer latex) is obtained.

[Coagulation step]
In the coagulation step S2, a polymer latex, a coagulant, and water are each supplied into the coagulation tank 30 at a set temperature and stirred by the stirrer 34 to produce water-containing crumbs. The set temperature (the temperature of the coagulant aqueous solution) in the coagulation tank 30 is controlled by the temperature controller 33 to be usually 40°C or higher, preferably 40 to 90°C, more preferably 50 to 80°C.

Specifically, in the coagulation step S2, the polymer latex, the coagulant, and the water are continuously supplied into the coagulation tank 30 at respective supply temperatures and set supply amounts, and are made to flow under agitation, and the set supply amounts are and produce wet crumbs in the coagulation tank 30 depending on the strength of the agitation and the supply and set temperatures. In this embodiment, an emulsion polymerization liquid (polymer latex) is added to the coagulant aqueous solution being stirred in the coagulation tank 30 . The produced water-containing crumbs are allowed to overflow from the coagulation tank 30 together with hot water and taken out of the coagulation tank 30 .

The strength of the stirring is determined by the number of revolutions, rotational speed, etc. of the stirring blades 35 of the stirring device 34 . Strong stirring, that is, vigorous stirring is preferable because the grain size of the water-containing crumbs can be made small and uniform. If the strength of stirring is excessively strong, crumb particles having large and small crumb particle sizes will be produced. If the shape and crumb particle size of the produced water-containing crumbs are uniform and aggregated within a desired range, the removal of emulsifiers and coagulants during washing and dehydration is significantly improved, which is preferable.

In the present embodiment, in the coagulation step S2, the polymer latex, the coagulant, and the water are continuously supplied into the coagulation tank 30 at their respective supply temperatures and set supply amounts, and stirred. Water-containing crumbs can be continuously produced in the coagulation tank 30 according to the supply temperature and the set temperature, and the produced water-containing crumbs can be overflowed from the coagulation tank 30 together with hot water to be efficiently taken out of the tank. can.

Also, the supply water overflowing from the coagulation tank 30 is separated from the water-containing crumb, stored in a tank, and circulated so as to be supplied to the coagulation tank 30 again. As a result, the water used in coagulating the polymer latex to form a water-containing crumb can be reused, and the amount of waste water during the production of synthetic rubber can be reduced. In this case, the overflowed hot water can be recirculated to the coagulation tank 30 side. It is also possible to adopt a configuration in which hot water is returned to the retention tank.

[Washing process]
In the washing step S3, the wet crumbs and washing water are supplied to the washing tank 40 at a set washing temperature, and stirred by the stirring device 44 to wash the wet crumbs. The temperature of the cleaning water in the cleaning tank 40 is controlled by the temperature control unit to be generally 40°C or higher, preferably 40 to 100°C, more preferably 50 to 90°C, and most preferably 60 to 80°C. do.

Further, in the washing step S3, the washed wet crumbs are allowed to overflow from the washing tank 40 together with the washing water to be taken out of the washing tank 40, and the water-containing crumbs within a predetermined temperature range with respect to the set washing temperature are removed by the drainer 49. It is supplied to the material supply zone 150 of the die extrusion dryer 5 (crumb supply step). The temperature of the wet crumbs supplied to the screw-type extruder dryer 5 is preferably 60° C. or higher. The temperature of the wet crumbs is adjusted by directly heating the wet crumbs using the heating device 41, but the temperature of the washing water may be adjusted, or the heating device 41 may be used to heat the wet crumbs directly. It may be adjusted by heating, and the temperature of the washing water may be adjusted. By setting the set washing temperature to a temperature suitable for the washing and extrusion drying steps, for example, 40° C. or higher, the effect of washing the wet crumbs can be enhanced, and the efficiency of dehydration and extrusion drying can be enhanced.

[Extrusion drying process]
In the extrusion drying step S4, the washed water-containing crumbs are taken into the material supply zone 150 of the screw-type extrusion dryer 5, compressed and dewatered by the screw-type extrusion dryer 5, and then heated and kneaded to evaporate the water content, thereby obtaining a predetermined content. Synthetic rubber with less water content is extruded into a sheet.

Specifically, in the extrusion drying step S4, the water-containing crumbs supplied to the material supply zone 150 are compressed and dehydrated by the screw-type extrusion dryer 5, and then heated and kneaded to evaporate the water content, and the water content is reduced to a predetermined water content or less. The synthetic rubber is continuously extruded into a sheet having a thickness of 50 mm or less, for example.

Also, the water separated from the water-containing crumbs by compression dehydration in the extrusion drying step S4 is supplied to a tank (not shown). As a result, water with a low coagulant concentration generated for dehydrating the wet crumbs can be reused, and the amount of wastewater can be sufficiently reduced.

Note that the dehydration step and the drying step may be performed as different steps. For example, the dehydration step may be performed using a dehydrator such as a centrifugal separator or a squeezer, and the drying step may be performed using a dryer such as a hot air dryer, a reduced pressure dryer, an expander dryer, or a kneader dryer.

[Conveyance cooling process]
In the transport cooling step S5, the sheet-like synthetic rubber 15 extruded from the screw-type extrusion dryer 5 is transported by the conveyor 61 of the transport-type cooling device 6 and cooled to a predetermined cooling temperature.

Specifically, in the transport cooling step S5, the sheet-shaped synthetic rubber 15 extruded from the screw-type extrusion dryer 5 is transported by the conveyor 61 of the transport cooling device 6, and the temperature at the time of extrusion is reduced to 60°C or less. is preferably cooled to a predetermined cooling temperature set between 20°C and 50°C at a cooling rate of 40°C/hr or more. As a result, the sheet-like synthetic rubber 15 can be more stably cut at the front end side of the sheet-like synthetic rubber 15 .

By cooling to a predetermined cooling temperature at a cooling rate of 40° C./hr or more, scorching during processing of the sheet-like synthetic rubber 15 is effectively suppressed, and excellent processing stability can be achieved. In addition, by setting the predetermined cooling temperature between 20° C. and 50° C., for example, the sheet-like cutting process at the front end side of the sheet-like synthetic rubber can be performed in the latter stage of the conveying cooling step S5. The processing of the synthetic rubber 15 can be easily and stably executed.

In addition, the conveying and cooling step S5 may include a conveying step of conveying the synthetic rubber sheet 15 continuous with a predetermined width by a roller conveyer 14 or the like.

[Cutting process]
In the cutting step S6, the sheet-like synthetic rubber 15 cooled by the conveying cooling device 6 is cut by the cutting device 7 to obtain a cut sheet-like synthetic rubber 16. FIG. Specifically, the front end portion of the sheet-shaped synthetic rubber 15 cooled to a predetermined cooling temperature of 60° C. or less by the conveying cooling device 6 is conveyed between the pair of rollers 75 adjacent to each other on the roller conveyor 74 . At the position, the cutting device 7 cuts into cut sheets of a predetermined length.

As a result, while the extrusion temperature in the extrusion drying step S4 is set relatively high to ensure a sufficient extrusion rate, the sheet-like synthetic rubber 15 can be stably cut into cut sheets on the front end side thereof. can. Further, since the front end portion of the sheet-like synthetic rubber 15 cooled to a predetermined cooling temperature is cut into cut sheets between the adjacent rollers 75 of the roller conveyor 74, the cooled sheet-like synthetic rubber 15 can be cut into a constant size while being stably supported on the roller conveyer 74, resulting in excellent processing stability.

In addition, the synthetic rubber veil 83 in which a plurality of cut sheets are substantially integrated can be obtained by simply laminating the cut sheet-like synthetic rubber 16 that is sufficiently cooled on the sheet to stabilize its shape. Since it can be easily produced, it becomes a production method capable of providing a rubber product excellent in shape stability.

In this embodiment, the cooled sheet-like synthetic rubber 15 is stably supported on the roller conveyor 74 and held by the clamper 77 while the cutting operation is performed, so that the processing stability is further improved. .

Further, in the cutting step S6, based on the amount of rotation of the registration rollers 76 rotating while being in close contact with the sheet-like synthetic rubber 15 on the roller conveyor 74, the synthetic rubber is cut from a predetermined conveying position for cutting the sheet-like synthetic rubber 15. Measure the feed amount to the tip. At the same time, a weight measuring device 78 provided on the downstream side of the cutting device 7 measures the weight of the cut synthetic rubber 16 in the form of a cut sheet. Then, according to the deviation of the measured weight value from the specified weight value, the predetermined length L (the length in the conveying direction) of the cut sheet-like synthetic rubber 16 is adjusted. In this way, variations in the weight of the synthetic rubber 16 in the form of cut sheets can be checked one by one, and variations in manufactured products can be suppressed. As a result, the synthetic rubber veil 83 can be manufactured efficiently while suppressing variations in weight.

Further, in the cutting step S6, the sheet-like synthetic rubber 15 cooled to a predetermined cooling temperature is intermittently conveyed downstream in the conveying direction and intermittently conveyed downstream of the intermittently conveyed section. A speed absorbing region is set on the upstream side to absorb the difference in the conveying speed of the sheet-like synthetic rubber 15, and the tip side portion of the sheet-like synthetic rubber 15 in the stopped state is cut into a sheet of a predetermined length by a cutting blade 70. cut to

As a result, when the sheet-shaped synthetic rubber 15 stops due to intermittent transportation on the downstream side in the transportation direction, the speed difference between the intermittent transportation section and the transportation section on the upstream side is reduced by the change in the transportation attitude of the sheet-shaped synthetic rubber 15. It can be absorbed, and it is possible to prevent unnecessary force from acting on the front end portion of the sheet-shaped synthetic rubber 15 in the stopped state. Therefore, tilting and twisting of the cut surface of the rubber sheet during the cut sheet cutting process can be effectively suppressed, and stable cutting can be performed to obtain a good cut surface.

Further, in the cutting step S6, the registration rollers 76 provided in front of a predetermined conveying position where the sheet-like synthetic rubber 15 is cut by the cutting blade 70 cause the sheet-like synthetic rubber 15 to be conveyed and conveyed to be stopped at a predetermined timing. Do it repeatedly. This makes it possible to control the length of the sheet-like synthetic rubber 15 supplied to the predetermined conveying position where the sheet-like synthetic rubber 15 is cut by the cutting blade 70 .

Further, the conveying speed V of the sheet-like synthetic rubber 15 in the conveying cooling step S5, and the roller conveyor 74 or registration roller 76 provided upstream from the predetermined conveying position where the sheet-like synthetic rubber 15 is cut by the cutting blade 70 are Conveyance operation time T1 for conveying the sheet-shaped synthetic rubber 15, conveying average speed V1 for conveying the sheet-shaped synthetic rubber 15 by the roller conveyor 74 or the registration rollers 76 during the conveyance operation time T1, the roller conveyor 74 or the registration rollers 76 is the conveyance stop time T2 for stopping the conveyance of the sheet-shaped synthetic rubber 15,
V=V1×T1/(T1+T2)
Set to satisfy the following formula.

Here, the conveying speed V is the tip speed of the sheet-like synthetic rubber 15 extruded from the screw-type extrusion dryer 5, and is substantially the same as the extrusion speed. Alternatively, it is the average value of the conveying speed of the registration rollers 76 . For example, a control device (not shown) provided with the synthetic rubber manufacturing system 1, the cutting device 7, etc., controls the driving conditions (conveyance operation time T1, conveyance stop time T2, conveying speed, etc.) may be set.

In this manner, the sheet-like synthetic rubber can be supplied at an appropriate timing to the predetermined transfer position where the sheet-like synthetic rubber is cut by the cutting blade according to the transfer speed of the sheet-like synthetic rubber in the transfer cooling step. Thus, a series of processes can be performed continuously for a long time while preventing abnormal bending and abnormal tension of the sheet-like synthetic rubber.

Further, when the predetermined length (the length in the conveying direction) of the cut sheet-shaped synthetic rubber 16 is L,
L=V1×T1
Set to satisfy the following formula. As a result, according to the predetermined length L of the cut sheet-shaped synthetic rubber 16, the sheet-shaped synthetic rubber 15 is cut by a roller conveyor 74 or a registration roller 76 provided upstream from a predetermined transport position where the sheet-shaped synthetic rubber 15 is cut. The transfer speed or transfer operation time of the synthetic rubber 15 can be set.

Further, on the upstream side of the roller conveyor 74, a deflection allowance portion 79 is provided to allow deflection of the sheet-like synthetic rubber 15 in the conveying direction. The deflection allowance portion 79, which is a speed absorbing area, allows the sheet-shaped synthetic rubber 15 to sag by loosening it. The bending of the synthetic rubber 15 is allowed, and the roller conveyor 74 or the registration roller 76 can temporarily stop the conveying operation.

[Bale process]
In the baling step S7, dry rubber having a predetermined water content or less is baled. Specifically, the cut sheet-like synthetic rubber 16 cut by the cutting device 7 is sequentially stacked in the bale forming device 8 on the downstream side of the roller conveyer 74 until it reaches a predetermined thickness or weight to form a bale. do. As a result, the synthetic rubber veil 83, which is easy to handle and to process such as cutting, can be efficiently manufactured. The baling can also be performed by putting the dried rubber obtained through the drying process into a baler and compressing it.

In the present embodiment, the sheet is extruded by the screw-type extrusion dryer 5 to sufficiently reduce the water content, and then laminated to form the synthetic rubber veil 83. Therefore, the adhesive rubber-like polymer is baled as it is as a crumb. Compared to the case of using rubber, not only is the easiness of handling significantly improved, but also the contamination of impurities can be effectively suppressed, and the quality as a material for rubber products can be improved.

According to the method for producing synthetic rubber according to the present embodiment, it is possible to efficiently produce synthetic rubber such as acrylic rubber that is suitable for various rubber products that require high-temperature oil resistance, water resistance, storage stability, and the like. In particular, when an emulsion polymerization liquid obtained by emulsion polymerization of a monomer component containing a reactive group-containing monomer in the presence of a divalent phosphoric acid emulsifier is coagulated with a magnesium salt, an acrylic rubber having excellent storage stability and water resistance can be obtained. can be manufactured.

INDUSTRIAL APPLICABILITY As described above, the present invention has the effect of effectively suppressing the tilting and twisting of the cut surface of a rubber sheet and obtaining a good cut surface, and is useful in general synthetic rubber manufacturing methods. be.

1 Synthetic rubber manufacturing system 3 Coagulating device 4 Washing device 5 Screw type extrusion dryer (extrusion dryer)
6 Transport-type cooling device 7 Cutting device 8 Baling device 11 Die part 15 Sheet-like synthetic rubber 16 Cut sheet-like synthetic rubber 30 Solidification tank 40 Cleaning tank 61 Conveyor 65 Cooling means 70 Cutting blade 74 Roller conveyor 75 Roller 76 Registration roller 77 Clamper 78 Weight measuring instrument 79 Deflection allowance (velocity absorption area)
83 Synthetic rubber bale 150 Material supply zone

Claims (3)

a coagulation step of supplying a polymer latex, a coagulant and water into a coagulation tank at a set temperature and agitating them to produce water-containing crumbs;
a washing step of supplying the water-containing crumbs and washing water to a washing tank and agitating them to wash the water-containing crumbs;
The wet crumbs after washing are supplied to the material supply zone of an extrusion dryer, and after being compressed and dehydrated by the extrusion dryer, the moisture is evaporated by heating and kneading, and a synthetic rubber having a predetermined moisture content or less is extruded in the form of a sheet. an extrusion drying process;
a conveying cooling step of conveying the extruded sheet-shaped synthetic rubber by a conveyor and cooling it to a predetermined cooling temperature;
The sheet-like synthetic rubber cooled to the predetermined cooling temperature is intermittently conveyed on the downstream side in the conveying direction, and a speed absorption region is set on the upstream side of the intermittent conveying section for absorbing the conveying speed difference of the sheet-like synthetic rubber. and a cutting step of cutting the front end side portion of the sheet-shaped synthetic rubber in the stopped state into a cut sheet of a predetermined length with a cutting blade ,
A registration roller provided in front of a predetermined conveying position where the sheet-like synthetic rubber is cut by the cutting blade repeatedly conveys and stops conveying the sheet-like synthetic rubber at a predetermined timing,
A conveying speed V of the sheet-shaped synthetic rubber in the conveying and cooling step, a conveying operation time T1 during which the registration rollers convey the sheet-shaped synthetic rubber, and the sheet-shaped synthetic rubber during the conveying operation time T1 of the registration rollers and the transport stop time T2 during which the registration roller stops transporting the synthetic rubber sheet,
V=V1×T1/(T1+T2)
is set to satisfy the expression of
When the cut sheet-like synthetic rubber has a predetermined length L,
L=V1×T1
is set to satisfy the expression of
Based on the amount of rotation of the registration rollers, the amount of feed from a predetermined conveying position for cutting the sheet-like synthetic rubber to the tip of the synthetic rubber is measured, and the weight of the cut sheet-like synthetic rubber is measured. and adjusting the predetermined length L of the cut sheet-like synthetic rubber in accordance with the deviation of the measured weight value from a specified weight value. 2. The method of manufacturing synthetic rubber according to claim 1 , wherein a deflection allowance portion is provided in front of the registration rollers to allow deflection of the sheet-like synthetic rubber in the conveying direction. 3. The method for producing synthetic rubber according to claim 1, wherein the synthetic rubber is acrylic rubber.

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