JP4928315B2 - Continuous mixing equipment - Google Patents

Description

  The present invention relates to a continuous mixing apparatus that can continuously and efficiently produce a kneaded body in which rubber and chemicals are uniformly dispersed by combining a closed rubber mixer and a continuous mixer.

  A kneading step in which rubber is kneaded with various chemicals such as a reinforcing agent (carbon, silica, etc.), a vulcanizing agent (sulfur), a softening agent (oil, etc.) to form a kneaded body that is a raw rubber for vulcanization. Then, as shown in FIG. 8, it is performed in two steps, a master kneading step a1 and a final kneading step a2.

  Specifically, in the master kneading step a1, conventionally, a closed rubber mixer b such as a Banbury mixer is used to knead the first chemical containing the reinforcing agent and not containing the vulcanizing agent and the raw rubber. Here, the reason why the reinforcing agent is separated from the vulcanizing agent and kneaded first in a separate process is because the reinforcing agent such as carbon and silica is in the form of fine powder and is particularly difficult to disperse, For this reason, it is necessary to use the hermetic rubber mixer b and knead in a closed system at a high temperature exceeding the vulcanization temperature with sufficient time. The rubber g1 discharged from the hermetic rubber mixer b is in the form of a lump, so that it is inferior in handleability. Therefore, the rubber g1 is managed in a state of being processed (sheeted) by, for example, a roller head extruder c. At this time, when the sheeted rubber g1 is stored at a high temperature, the rubber g1 adheres to each other, so that it is cooled in the cooling step d and an anti-adhesive agent is applied.

  In contrast, in the final kneading step a2, a sealed rubber mixer b is used to vulcanize the cooled sheet-like rubber g1 together with a second chemical containing a vulcanizing agent and no reinforcing agent. Re-kneading on a lower temperature group. The discharged rubber g2 is sheeted and stored through the cooling step d as in the master kneading step a1.

  However, in such a conventional method, when the rubber k1 kneaded with the master is put into the final kneading step a2, it is necessary to apply sheeting, cooling, and an anti-adhesive agent. Invite. In addition, since the master-kneaded rubber g1 is generated as an intermediate stock, there arises a problem that the storage space is increased and the management work is increased. In addition, there is a problem that energy efficiency is poor, for example, the high-temperature rubber g1 kneaded at the master is once cooled and then heated again at the vulcanization temperature or lower in the final kneading step a2.

  Therefore, the present invention can suppress the increase in work time, cost increase, generation of intermediate stock, increase in storage space, and increase in management work as described above, and also improve energy efficiency, and provide a reinforcing agent and a vulcanizing agent. An object of the present invention is to provide a continuous mixing apparatus that can uniformly knead a chemical and rubber contained therein without causing rubber burn (scorch).

JP 2005-53190 A

In order to achieve the above object, the invention of claim 1 of the present application is provided with a mixing chamber provided with a stirring rotor, and the raw rubber to be put into the mixing chamber is masticated, or the raw rubber to be added simultaneously with the first A hermetic rubber mixer that kneads the above chemicals and discharges them in bulk from the openable outlet provided in the mixing chamber as a primary rubber,
The primary rubber discharged from the discharge port is received by a primary rubber hopper, and the received primary rubber is kneaded together with a second chemical charged from a chemical supply port that opens downstream from the primary rubber hopper. And a single screw type first continuous mixer that continuously extrudes from the extrusion port at the front end as a secondary rubber,
The secondary rubber extruded from the extrusion port is received by a secondary rubber hopper, and the received secondary rubber is further kneaded and continuously discharged from the discharge port at the front end as a tertiary rubber. 2 continuous mixers,
In addition, the first continuous mixer is supported in a non-contact manner between the closed rubber mixer and the second continuous mixer, and the first continuous mixer has a weight of the first continuous mixer. A weight meter capable of measuring the weight of the primary rubber received from the sealed rubber mixer by measuring
The second continuous mixer intersects with a long main screw shaft housed in a main flow channel leading from the secondary rubber hopper to the discharge port, and inclined to the main flow channel behind the discharge port. The main screw shaft and the sub screw shaft are different from each other in the rotation direction and the winding direction of the screw.

  In the invention of claim 2, the first chemical includes at least a reinforcing agent and does not include a vulcanizing agent, and the second chemical includes at least a vulcanizing agent and does not include a reinforcing agent. It is a feature.

  According to a third aspect of the present invention, the chemical supply port is provided with non-contact chemical supply means for charging the second chemical into the chemical supply port. The chemical supply amount is set based on the measured value.

  As described above, the continuous mixing apparatus of the present invention includes a hermetic rubber mixer, a single screw type first continuous mixer, and a twin screw type second continuous mixer. . The first continuous mixer includes a primary rubber hopper that receives the high temperature primary rubber discharged from the hermetic rubber mixer in a lump. Therefore, it is not necessary to manage the primary rubber in the form of a sheet, and there is no need for sheeting, cooling, and application of an anti-adhesive agent, which increases work time, increases costs, generates intermediate inventory, increases storage space, and performs management work. The increase in the amount can be suppressed.

  In addition, the first continuous mixer includes a second chemical supply port for charging chemicals on the downstream side of the hopper for primary rubber. Accordingly, the primary rubber can be cooled while the high temperature primary rubber that has been fed is transferred from the primary rubber hopper to the chemical supply port. The first continuous mixer is non-sealed and does not receive high pressure, so that the temperature rise can be suppressed. In combination with the cooling, the first continuous mixer can be kneaded at a temperature lower than the vulcanization temperature. The second chemical containing the vulcanizing agent can be kneaded and dispersed without causing scorching.

  However, a single-screw type continuous mixer is continuously extruded while being stirred by a screw shaft in a single cylinder. Therefore, although it is dispersed to some extent in a cross section perpendicular to the axial direction, The uniformity of the dispersion is inferior, for example, the density appears in the mixing ratio with respect to the direction.

  Therefore, in the present invention, a twin screw type second continuous mixer is connected downstream of the first continuous mixer to improve uniformity. This second continuous mixer combines a long main screw shaft and a short sub screw shaft. Therefore, rubber stays in the region where the screw shafts are arranged in parallel, and the dispersibility of the chemicals in the axial direction can also be improved, such as kneading of the rubber charged first and the rubber charged later. . In addition, since the extrusion pressure is strongly applied to the rubber at the tip side portion where only the main screw shaft is provided, it is possible to perform extrusion molding with a predetermined cross-sectional shape as required.

The first continuous mixer is provided with a weigh scale for measuring the weight of the first continuous mixer in a non-contact manner with the hermetic rubber mixer and the second continuous mixer. Therefore, the weight of the primary rubber received from the hermetic rubber mixer can be measured, and the supply amount of the second chemical can be accurately set based on the measured value. In the first continuous mixer, the rubber extrusion amount (extrusion speed) is considered to be basically constant, but is not strictly constant because of variations such as the degree of rubber biting. However, by using the weighing scale, it is possible to capture a temporal change in the weight of the first continuous mixer, that is, a change in the rubber extrusion amount. As a result, based on the change in the rubber extrusion amount, for example, It is possible to accurately supply chemicals, for example, by adjusting the time interval for charging the chemicals 2 and the amount of one chemical charged.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a schematic side view conceptually showing the continuous mixing apparatus of the present invention.

  As shown in FIG. 1, the continuous mixing apparatus 1 of the present embodiment includes a hermetic rubber mixer 2, a single screw type first continuous mixer 3, and a twin screw type second continuous mixer 4. With.

  As shown schematically in FIG. 2, the sealed rubber mixer 2 is a small Banbury mixer having a kneading capacity of 300 liters or less, for example, and is provided with a pair of agitating rotors 5 and 5 arranged in parallel. Provided in the mixing chamber 6 as a primary rubber G1 comprising a mixing chamber 6 for kneading the raw rubber put into the mixing chamber 6 or kneading the raw rubber and the first chemical charged simultaneously. It is discharged in a lump form from the openable discharge port 7. In this example, the case where the master-kneading process which knead | mixes the said raw material rubber and the 1st chemical | medical agent which contains a reinforcing agent and does not contain a vulcanizing agent by the sealed rubber mixer 2 is illustrated. Examples of the reinforcing agent include carbon (carbon black) and silica as described above.

  The stirring rotor 5 has a well-known configuration in which a stirring blade is provided, for example, spirally around a base shaft that is rotatably supported, and is disposed in a mixing chamber 6 provided in the mixer body 8. Each agitating rotor 5 is rotationally driven in the same direction or in the opposite direction via drive means (not shown) including a motor attached to the mixer main body 8. The mixing chamber 6 has a cross-sectional gourd shape connecting two circumferential surfaces concentric with the pair of stirring rotors 5, 5, and the constricted portion includes the raw rubber and the first chemical (collectively, The lower end of the vertical hole 10 leading to the insertion port 9 through which the material rubber (which may be referred to as raw rubber or the like) is introduced is connected. The vertical hole 10 is provided with a floating weight 11 supported by a cylinder or the like so as to be movable up and down. The floating weight 11 pressurizes the raw rubber or the like put into the mixing chamber 6 and improves the stirring efficiency and kneading efficiency by the stirring rotor 5. The loading port 9 is provided with a carry-in conveyor 12 for carrying the raw rubber and the like next to it.

  The mixer main body 8 is provided with a drop door 13 that opens and closes the discharge port 7 formed in the lower portion of the mixing chamber 6, and the kneaded primary rubber G 1 is lumped from the discharge port 7 by opening the drop door 13. Eject and drop with.

  Next, the first continuous mixer 3 receives the primary rubber G1 discharged from the discharge port 7 by the primary rubber hopper 15 and receives the received primary rubber G1 from the primary rubber hopper 15. It kneads | mixes with the 2nd chemical | medical agent thrown in from the chemical | medical agent supply port 16 opened in the downstream, and continuously extrudes from the extrusion port 17 of the front end as secondary rubber G2.

  Specifically, the first continuous mixer 3 has a cylinder 18 having the primary rubber hopper 15 on the rear end side and the opening 17 opened on the front end, and is rotatable in the cylinder 18. The cylinder 18 is provided with a second chemical supply port 16 for charging chemicals between the hopper 15 and the extrusion port 17. The screw shaft 19 is connected to driving means including a motor, and the screw shaft 19 is rotationally driven, whereby the second chemical containing the vulcanizing agent and not containing the reinforcing agent is added. The rubber is pushed while being kneaded with the primary rubber G1, and discharged from the extrusion port 17 as a secondary rubber G2. Examples of the vulcanizing agent include sulfur.

At this time, between the hopper 15 and the chemical supply port 16, the first continuous mixer 3 has a temperature lower than the vulcanization temperature while pushing the high temperature primary rubber G <b> 1 charged. A cooling region for cooling is formed, and a kneading region for mixing the primary rubber G1 and the second chemical at a temperature lower than the vulcanization temperature is formed between the chemical supply port 16 and the extrusion port 17. Yes. For this purpose, the cylinder 18 includes a cooling means (not shown) using, for example, cooling water for cooling the primary rubber G1 at least in the cooling region, and a thermometer for measuring the temperature of the cooled primary rubber G1 (not shown). (Not shown).

  Next, the first continuous mixer 3 measures the weight (input weight Wg1) of the primary rubber G1 received from the hermetic rubber mixer 2 by measuring the weight of the first continuous mixer 3. A possible weight scale 21 is provided, and a chemical supply means 22 for supplying the second chemical is disposed in the chemical supply port 16.

  And in the said chemical | medical agent supply means 22, while supplying the chemical | medical agent supply amount wg2 based on the measured value of the said weighing scale 21, this set chemical | medical agent supply amount wg2 is the said 1st continuous mixer 3 in this example. Is supplied in a plurality of divided portions at a rate corresponding to the rubber extrusion speed (the weight of rubber extruded per unit time).

  Specifically, from the measured value of the weigh scale 21, in addition to the input weight Wg 1, as shown schematically in FIG. 6, the time change of the weight of the first continuous mixer 3, that is, “weight-time "Curve f can be obtained, and from the slope of this" weight-time "curve f, the rubber extrusion amount per unit time from the first continuous mixer 3 and the change in the rubber extrusion amount can be known. . Therefore, for example, when the rubber extrusion amount ΔWg1 per unit time Δt of the first continuous mixer 3 is obtained from the slope of the “weight-time” curve f, the primary rubber G1 charged in a lump is (Wg1 / It is discharged in a time of ΔWg1) × Δt. Therefore, by supplying the chemical supply amount wg2 set from the input weight Wg1 at a rate of wg2 × ΔWg1 / Wg1 per unit time Δt, uniform supply to the primary rubber G1 is possible. Also, when the rubber extrusion amount ΔWg1 changes during the extrusion, the second chemical supply amount per unit time Δt or the second chemical injection time interval can be adjusted according to this change, It becomes possible to perform uniform supply more reliably. The setting of the chemical supply amount wg2 based on the measurement value of the weighing scale 21, and the supply of the set chemical supply amount wg2 according to the rubber extrusion amount ΔWg1 (adjustment of the charging time interval and per unit time Δt) (Including the adjustment of the supply amount) is performed using a control means 22A such as a computer provided in the chemical supply means 22. Further, the first continuous mixer 3 includes the hermetic rubber mixer 2, the second continuous mixer 4, and the chemical supply means 22 so that the measurement by the weighing scale 21 is accurately performed. Arranged without contact.

  In this example, the medicine supply means 22 includes a storage hopper 23 that stores the second medicine for each type, and a medicine that is transported from each storage hopper 23 via a transport pipe 24 as shown in FIG. For example, a weighing hopper 25, a measuring means 26 for measuring the weight of the medicine sent to the weighing hopper 25, and a feeding pipe 27 for feeding the weight-measured medicine into the medicine supply port 16. The measuring means 26 is a weigh scale, measures the weight of the chemical transferred to the weighing hopper 25, and outputs it to the control means 22A. And the control means 22A, until the chemical weight reaches the supply amount per unit time Δt of the second chemical set from the input weight Wg1 of the primary rubber G1, or until the supply amount for one predetermined time, The feeder of the conveyance pipe 24 is operated. Similarly to the transfer tube 24, the feeding tube 27 is provided with a feeder such as an electromagnetic vibration type and a screw type, and a predetermined second chemical transferred to the weighing hopper 25 is instructed from the control means 22A. The medicine is fed into the chemical supply port 16 at a charging time interval.

  Next, the second continuous mixer 4 receives the secondary rubber G2 extruded from the extrusion port 17 by the secondary rubber hopper 30, and further kneads the received secondary rubber G2 to obtain the tertiary rubber. G3 is continuously discharged from the discharge port 31 at the front end. The reason why the second continuous mixer 4 is provided is that the single screw type first continuous mixer 3 is inferior in stirring effect, and in the cross section perpendicular to the axial direction, the primary rubber G1 and the second chemical Is distributed uniformly to some extent, but in the axial direction, the mixing ratio becomes coarse and dense, and the dispersion becomes non-uniform compared to a closed rubber mixer. Therefore, in the present invention, the second continuous mixer 4 is continuously provided to improve the uniformity of dispersion.

  As shown in the sectional view of the second continuous mixer 4 in a top view in FIG. 4, the second continuous mixer 4 is separated from the main flow path 32 leading from the secondary rubber hopper 30 to the discharge port 31 and from the discharge port 31 to the rear. A housing 36 provided with a sub-flow path 34 inclined and intersecting with the main flow path 32 at the intersection position Q, a long main screw shaft 33 housed in the main flow path 32, and housed in the sub-flow path 34. A short screw shaft 35 is provided. The secondary rubber hopper 30 has a large opening across both the main flow path 32 and the sub flow path 34. In this example, the front end of the housing 36 is attached with an extrusion head 37 having an extrusion die that molds and extrudes the tertiary rubber G3 into a desired cross-sectional shape. Then, it forms as a nozzle opening of the base. A drive means 39 such as a gear box including a motor for rotating the main screw shaft 34 and the sub screw shaft 35 in opposite directions is attached to the rear end of the housing 36.

  In the present example, the main screw shaft 33 is a so-called taper screw shaft whose thickness gradually increases from the front end portion toward the rear, the thickness including the screw blade 33A, and the base shaft portion 33B excluding the screw blade 33A. Both thicknesses are formed in a tapered shape. In this example, the protrusion height of the screw blade 33A from the base shaft portion 33B is constant over the entire length, and the helical pitch of the screw blade 33A gradually increases toward the rear.

  The auxiliary screw shaft 35 is also a taper screw shaft whose thickness gradually increases from the tip portion toward the rear, and like the main screw shaft 33, the protruding height of the screw blade 35A from the base shaft portion 35B is as follows. The spiral pitch of the screw blade 35A is constant over the entire length and gradually increases toward the rear. In the parallel region Y where the auxiliary screw shaft 35 and the main screw shaft 33 are arranged in parallel, in this example, the auxiliary screw shaft 35 has a smaller diameter than the main screw shaft 33, and the screw blade 35A and the screw blade 33A. Means that the winding direction of the spiral (screw) is reversed and the spiral pitch is the same, and the phase of the spiral pitch is shifted in the length direction by a half pitch so as not to interfere with each other during rotation. .

  Further, the main flow path 32 and the sub flow path 34 are tapered holes for accommodating the main screw shaft 33 and the sub screw shaft 35 concentrically with a predetermined clearance, respectively, and are cross sections taken along line AA in FIG. As shown in FIG. 5, in the parallel region Y, there is no partition partitioning the flow paths 32, 34 between the screw shafts 33, 35, and they are connected to each other by a smooth bottom surface S. Further, at the intersection position Q, as shown in FIG. 4, the tip of the sub-channel 34 intersects the main channel 32 in a stepped manner via a planar front wall portion 38 in this example.

  In such a second continuous mixer 4, the secondary rubber G <b> 2 to be charged is caught between the screw shafts 33 and 34 and stirred, whereby the dispersibility of the second chemical is increased. In addition, the secondary rubber G2 pushed by the screw shafts 33 and 34 has a cross-sectional area of the rubber flow path that decreases stepwise from the intersection position Q. Occurs. In particular, the front wall portion 38 is highly effective in the retention of rubber, and this retention increases the opportunity for kneading between the rubber that is introduced first and the rubber that is introduced later, and the second direction also in the axial direction. Dispersibility of chemicals can be increased.

In the second continuous mixer 4, an extrusion pressure is strongly applied to the secondary rubber G <b> 2 by the main screw shaft 33 at a portion on the tip side from the intersecting position Q where only the main screw shaft 33 is provided. It becomes possible to perform extrusion molding into a predetermined cross-sectional shape using the head 37.

  Thus, in the continuous mixing apparatus 1 of the present invention, since the closed rubber mixer 2 is provided, a reinforcing agent such as carbon, silica, etc., which is particularly difficult to disperse, has a high temperature exceeding the vulcanization temperature in a closed system. The mixture can be kneaded at a low pressure and under a high pressure and for a sufficient time, and the dispersibility of the first chemical can be ensured as in the conventional master kneading. In addition, if it is a chemical | medical agent which is powdery and is hard to disperse | distribute, it can knead | mix at this stage as a 1st chemical | medical agent.

  Further, since the first continuous mixer 3 receives the high temperature primary rubber G1 discharged from the hermetic rubber mixer 2 in a lump form, there is no need to manage the primary rubber G1 in a sheet form as in the prior art. . This eliminates the need for sheeting, cooling, and application of an anti-adhesive agent, and can suppress an increase in work time, an increase in cost, generation of intermediate inventory, an increase in storage space, and an increase in management work. Moreover, the first continuous mixer 3 includes a chemical supply port 16 at a distance from the downstream side of the primary rubber hopper 15. Therefore, the primary rubber G1 can be cooled while the high temperature primary rubber G1 is moved from the primary rubber hopper 15 to the chemical supply port 16. Moreover, since the first continuous mixer 3 is non-sealed and high pressure does not act, the temperature rise can be suppressed, and in combination with the cooling, kneading can be performed at a temperature lower than the vulcanization temperature, The second chemical containing the vulcanizing agent can be kneaded and dispersed without causing rubber burn (scorch).

  In the second continuous mixer 4, the long main screw shaft 33 and the short sub screw shaft 35 are combined. Therefore, in the parallel region Y, the secondary rubber G 2 stays and is put in first. The opportunity for kneading between the rubber to be added and the rubber to be introduced later increases, and the dispersibility of the second chemical can be enhanced also in the axial direction. Moreover, since this 2nd continuous mixer 4 is also non-hermetic, a temperature rise (heat generation) can be suppressed. Furthermore, since the second continuous mixer 4 can strongly apply an extrusion pressure to the rubber, it is possible to perform extrusion using an extrusion head. In order to further improve dispersibility, the second chemical is preferably added in the form of granules or pellets instead of powder.

  In addition, the first continuous mixer 3 is provided with a weighing scale 21. Accordingly, the weight of the primary rubber G1 received from the sealed rubber mixer 2 can be measured, and the chemical supply amount wg2 of the second chemical can be accurately set based on the measured value, and the chemical supply amount wg2 It becomes possible to supply with high precision at a rate corresponding to the rubber extrusion speed of the first continuous mixer 3.

  As described above, the particularly preferred embodiment of the present invention has been described in detail. For example, in the sealed rubber mixer 2, it may be used for mastication of only the raw rubber without introducing the first chemical, etc. The present invention is not limited to the illustrated embodiment, and can be implemented in various forms.

It is sectional drawing which shows notionally one Example of the continuous mixing apparatus of this invention. . It is sectional drawing which expands and shows a sealing-type rubber mixer. It is sectional drawing which shows the 1st, 2nd continuous mixer schematically. It is sectional drawing which looked at the 2nd continuous mixer from the top. FIG. 5 is a cross-sectional view taken along line AA in FIG. 4. It is a graph of the "weight-time" curve which shows the time change of the weight of a 1st continuous mixer. It is a conceptual diagram which shows an example of a chemical | medical agent supply means. It is a conceptual diagram explaining a prior art.

Explanation of symbols

2 Sealed Rubber Mixer 3 Single Screw Type First Continuous Mixer 4 Twin Screw Type Second Continuous Mixer 5 Stirring Rotor 6 Mixing Chamber 7 Discharge Port 15 Primary Rubber Hopper 16 Chemical Supply Port 17 Extrusion Port 21 Weight meter 22 Chemical supply means 30 Secondary rubber hopper 31 Discharge port 32 Main flow path 33 Main screw shaft 34 Sub flow path 35 Sub screw shaft G1 Primary rubber G2 Secondary rubber G3 Tertiary rubber

Claims (3)

A mixing chamber provided with a stirring rotor is provided, and the raw rubber to be put into the mixing chamber is masticated, or the raw rubber and the first chemical added simultaneously are kneaded and provided as the primary rubber in the mixing chamber. A sealed rubber mixer that discharges in bulk from an openable discharge port;
The primary rubber discharged from the discharge port is received by a primary rubber hopper, and the received primary rubber is kneaded together with a second chemical charged from a chemical supply port that opens downstream from the primary rubber hopper. And a single screw type first continuous mixer that continuously extrudes from the extrusion port at the front end as a secondary rubber,
The secondary rubber extruded from the extrusion port is received by a secondary rubber hopper, and the received secondary rubber is further kneaded and continuously discharged from the discharge port at the front end as a tertiary rubber. 2 continuous mixers,
In addition, the first continuous mixer is supported in a non-contact manner between the closed rubber mixer and the second continuous mixer, and the first continuous mixer has a weight of the first continuous mixer. A weight meter capable of measuring the weight of the primary rubber received from the sealed rubber mixer by measuring
The second continuous mixer intersects with a long main screw shaft housed in a main flow channel leading from the secondary rubber hopper to the discharge port, and inclined to the main flow channel behind the discharge port. A continuous mixing apparatus comprising: a short auxiliary screw shaft housed in the auxiliary flow path, wherein the main screw shaft and the auxiliary screw shaft have different rotation directions and screw winding directions.   The first chemical includes at least a reinforcing agent and does not include a vulcanizing agent, and the second chemical includes at least a vulcanizing agent and does not include a reinforcing agent. Continuous mixing device.   The chemical supply port is provided with a chemical supply means for introducing the second chemical into the chemical supply port in a non-contact manner, and the chemical supply means determines the chemical supply amount based on the measurement value of the weighing scale. The continuous mixing apparatus according to claim 1, wherein: is set.

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