Pressing and dewatering machine for water-containing rubber wet masterbatches and method for manufacturing rubber wet masterbatches
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- MITSUBISHI CHEM CORP
- Filing Date
- 2024-11-11
- Publication Date
- 2026-05-21
AI Technical Summary
Conventional conical twin-screw extruders for dehydrating water-containing rubber wet masterbatches face issues with clogging of the drain port due to the accumulation of water-containing raw material, leading to operational interruptions and reduced yield and quality stability.
A press dewatering machine design with a casing, conical screws, and a drain port positioned behind a seal ring, where the inlet is located ahead of the seal ring, and the drain port's lowest end is above the casing's lowest point, without solid-liquid separation means, preventing raw material from entering the seal ring-rear end wall gap and ensuring efficient water discharge.
The design effectively prevents drain port clogging, maintaining or improving water discharge efficiency by allowing accumulated water to overflow from the drain port, thus ensuring continuous operation and high-quality dewatering.
Smart Images
Figure 2026084483000001_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a squeezing dehydrator for a water-containing rubber wet masterbatch and a method for producing a rubber wet masterbatch.
Background Art
[0002] A water-containing rubber wet masterbatch (hereinafter sometimes simply referred to as a water-containing raw material) often has a shape such as powder, pellet, spherical, etc., and the water-containing raw material often has viscosity. Therefore, when trying to squeeze and dehydrate a water-containing rubber wet masterbatch with a conventional conical twin-screw extruder, a parallel twin-screw extruder, etc., the drain port is clogged with the water-containing raw material, and it is necessary to frequently stop the operation and perform cleaning. In addition, the water-containing raw material may be discharged from the drain port, which may lead to a decrease in yield and deterioration of quality stability.
[0003] A conical twin-screw extruder for squeezing and dehydrating a water-containing raw material aimed at solving such problems is described in Patent Document 1.
[0004] The conical twin-screw extruder of Patent Document 1 includes a casing having a discharge port for a kneaded product at the tip and an inlet for a water-containing raw material at the rear, and two conical screws installed in the casing, and a drain port is provided in the casing. In the conical twin-screw extruder for squeezing a water-containing raw material, the lowermost end of the drain port is provided above the lowermost end in the casing. This drain port is provided in the rear end wall of the casing or in the rear part of the casing.
[0005] In one aspect of Patent Document 1, no solid-liquid separation means is provided at the drain port. Further, the inlet is separated from the rear end wall of the casing toward the tip side of the casing.
[0006] In one aspect of Patent Document 1, a seal ring is provided on the screw behind the rear end position of the inlet.
[0007] In the conical twin-screw extruder described in Patent Document 1, the seal ring is positioned slightly forward of the rearmost end of the screw flight, and the screw flight is located behind the seal ring. [Prior art documents] [Patent Documents]
[0008] [Patent Document 1] International Publication No. 2020 / 189500 [Overview of the project] [Problems that the invention aims to solve]
[0009] In the conical twin-screw extruder described in Patent Document 1, flights are present behind the seal ring. Therefore, if water-containing raw material (water-containing rubber wet masterbatch) or its dewatered material (dewatered rubber wet masterbatch) enters the space between the seal ring and the rear end wall, the water-containing raw material will attempt to be pushed forward by the flights behind the seal ring. However, this forward movement is blocked by the seal ring, causing the water-containing raw material to accumulate behind the seal ring, potentially clogging the drain port and making continuous operation of the conical twin-screw extruder difficult.
[0010] The object of the present invention is to provide a press dewatering machine for a water-containing rubber wet masterbatch and a method for manufacturing a rubber wet masterbatch that can maintain or improve the efficiency of water extraction and discharge from the water-containing raw material while preventing the water-containing raw material from clogging the drain port. [Means for solving the problem]
[0011] The gist of this invention is as follows:
[0012] [1] A casing having a discharge port for kneaded material at the front and an input port for water-containing raw materials on the upper surface of the rear, A rear end wall provided at the rear end of the casing, Two conical screws are installed inside the casing, A drainage port provided on the rear end wall or the lower surface of the rear of the casing and A press dewatering machine for a water-containing rubber wet masterbatch, having the following features: The screw comprises a rotor shaft, helical flights rising from the outer surface of the rotor shaft, and a seal ring rising from the rotor shaft behind the flights. The aforementioned loading port is located above the flight, A press dewatering machine for a water-containing rubber wet masterbatch, wherein the drain port is located behind the seal ring, and the lowest end of the drain port is positioned above the lowest end inside the casing.
[0013] [2] The water-containing rubber wet masterbatch pressing dewatering machine according to [1], characterized in that the drain port is provided in the rear end wall.
[0014] [3] The water-containing rubber wet masterbatch pressing dewatering machine according to [2], characterized in that the lowest end of the drain port is located in a range of 5 to 200 mm above the point where the inner surface of the rear end wall and the rearmost and lowest part of the inner surface of the casing intersect.
[0015] [4] The water-containing rubber wet masterbatch press dewatering machine according to [1], characterized in that the drain port is provided on the lower surface of the rear of the casing.
[0016] [5] A water-containing rubber wet masterbatch pressing machine according to any of [1] to [4], characterized in that the lower part of the inner surface of the casing has an upward slope from the rear end wall toward the discharge port.
[0017] [6] A water-containing rubber wet masterbatch pressing dewatering machine according to any of [1] to [5], characterized in that the drain port is not provided with a solid-liquid separation means.
[0018] [7] A method for manufacturing a rubber wet masterbatch, comprising a step of dewatering a rubber wet masterbatch containing water using a squeezing and dewatering machine for the rubber wet masterbatch containing water according to any one of [1] to [6].
Advantages of the Invention
[0019] According to the squeezing and dewatering machine of the present invention, while maintaining or improving the water discharge efficiency from the rubber wet masterbatch containing water, clogging (including suppression) of the water discharge port with the raw material containing water is prevented.
[0020] That is, in the squeezing and dewatering machine of the present invention, since the inlet is located in front of the seal ring, the raw material containing water (rubber wet masterbatch containing water) introduced into the casing from the inlet is suppressed from entering between the seal ring and the rear end wall. Further, in the squeezing and dewatering machine of the present invention, the water discharge port is provided such that the lowermost end of the water discharge port is located above the lowermost end of the casing, and the water accumulated at the rearmost part of the casing is discharged by overflowing from the water discharge port.
[0021] In the squeezing and dewatering machine of the present invention, a seal ring is provided on the rear side of the rear end of the screw, and no flight is provided behind this seal ring. Therefore, even if the raw material containing water or the like enters between the seal ring and the rear end wall, this raw material containing water or the like is not pressed against the seal ring by the flight and deposited. As a result, the water discharge port is prevented from being blocked by the rubber wet masterbatch containing water or the rubber wet masterbatch.
[0022] Even if a fine rubber wet masterbatch containing water or a rubber wet masterbatch enters between the seal ring and the rear end wall, it is discharged through the water discharge port, so the water discharge port is not blocked.
[0023] In one aspect of the present invention, since no solid-liquid separation means is provided at the water discharge port, clogging of the water discharge port is more sufficiently prevented.
Brief Description of the Drawings
[0024] [Figure 1] This is a longitudinal cross-sectional view of a compression dewatering machine according to an embodiment of the present invention. [Figure 2] Figure 1 is a horizontal cross-sectional view of the dewatering press. [Figure 3] This is a longitudinal cross-sectional view of a compression dewatering machine according to another embodiment of the present invention. [Figure 4] Figure 3 is a horizontal cross-sectional view of the compression dewatering machine. [Figure 5] Figures 3 and 4 are partial cross-sectional views perpendicular to the screw axis, illustrating the shape of the casing and screw of the press dewatering machine. [Modes for carrying out the invention]
[0025] [First Embodiment] A first embodiment of a dewatering press will be described with reference to Figures 1 and 2.
[0026] This dewatering press 1 has two screws 7 arranged inside a casing 2. A rear end wall 11 is provided at the rear end of the casing 2. A water-containing raw material inlet 3 for supplying water-containing raw material consisting of a water-containing rubber wet masterbatch is provided on the upper rear side of the casing 2, and a discharge port 4 for pushing out the dewatered rubber wet masterbatch is provided at the front end.
[0027] The input port 3 is located in front of the seal ring 8 of the screw 7 and above the flight 6 of the screw 7.
[0028] The distance between the rear end of the inlet 3 and the front surface of the seal ring 8 (the distance parallel to the axis of the screw 7) is preferably 10 mm or more, particularly 15 mm or more, and especially 20 mm or more. There is no particular upper limit to this length, but since it is necessary to secure an area in which the water-containing raw material is compressed between the screw 7 and the casing 2, it is preferably 1000 mm or less for a conical twin-screw extruder with a screw diameter of 200 mm.
[0029] The preferred distance between the rear end of the input port 3 and the front surface of the seal ring 8 depends on the size of the casing 2; a longer distance is preferable when the casing 2 is large, and a shorter distance is preferable when the casing 2 is small, etc.
[0030] The lower part of the inner surface of the casing 2 (specifically, the line segment projected onto the inner surface of the casing 2 when the axis of the rotor shaft 5 of the screw 7 is projected vertically downward) has an upward slope from the rear end wall 11 toward the discharge port 4.
[0031] The screw 7 is a conical screw 7 that transports and compresses the water-containing raw material fed in from the inlet 3. Each screw 7 has a rotor shaft 5, a helical flight 6 that rises from the outer circumference of the rotor shaft 5, and a seal ring 8 that rises from the outer circumference of the rotor shaft 5 and is connected to the rear end of the flight 6.
[0032] The two rotor shafts 5 are arranged such that the distance between them gradually decreases from the inlet 3 side to the discharge port 4 side. The outer diameter of the rotor shafts 5 and the outer diameter of the flights 6 are formed to decrease from the rearmost end to the discharge port 4 side. As a result, the screw 7 is a conical screw.
[0033] The rotor shafts 5 of the two screws 7 are positioned such that the angle between their axis lines is in the range of 10 to 40 degrees. The two screws 7 are positioned so that the flights 6 are meshed together.
[0034] The seal ring 8 is a ring-shaped plate that encircles the outer circumference of the rotor shaft 5, and its surface is approximately perpendicular to the axis of the rotor shaft 5. In this embodiment, the seal ring 8 is connected to the rearmost end of the flight 5, but it does not have to be connected. Not being connected prevents interference with the other flight.
[0035] No flight is provided between the seal ring 8 and the rear end wall 11.
[0036] It is preferable that the gap between the outer circumference of the seal ring 8 and the inner surface of the casing 2 be smaller than the diameter of most of the water-containing raw material. Specifically, the gap between the outer circumference of the seal ring 8 and the inner surface of the casing 2 is preferably 5 mm or less, more preferably 3 mm or less, even more preferably 1 mm or less, and particularly preferably 0.5 mm or less. This suppresses the movement of water-containing raw material behind the seal ring 8. Even if water-containing raw material passes through the gap between the flight 6, the seal ring 8, and the inner surface of the casing 2 and enters the portion between the seal ring 8 and the rear end wall 11, since there is no flight 6 in this portion, the water-containing raw material will not be pressed against the rear surface of the seal ring 8 and accumulate. Fine water-containing raw material that enters the space between the seal ring 8 and the rear end wall 11 flows out from the drain port 10 along with the compressed water.
[0037] The preferred range of the gap between the outer circumference of the seal ring 8 and the inner surface of the casing 2 depends on the size of the dewatering press 1 and the diameter of the water-containing raw material. A wider gap is preferable when the dewatering press 1 is large or the diameter of the water-containing raw material is large, and a smaller gap is preferable when the dewatering press 1 is small or the diameter of the water-containing raw material is small.
[0038] The distance between the outer circumference of Flight 6 and the inner surface of Casing 2 is preferably 5 mm or less, more preferably 1 mm or less, and even more preferably 0.5 mm or less. This prevents the water-containing raw material from moving from the inlet 3 to the drain outlet 10 and is transported to the discharge outlet 4 by the screw 7.
[0039] In this embodiment, the height of the seal ring 8 from the outer circumferential surface of the rotor shaft 5 is approximately equal to the height of the last flight 6 from the outer circumferential surface of the rotor shaft 5, but the embodiment is not limited to this.
[0040] The rotor shaft 5 of each screw 7 is cantilevered at its large-diameter rear end to the rear end wall 11 of the casing 2, and the drive unit 9 is connected to it. The front surface of the rear end wall 11 is perpendicular to the axis of the rotor shaft 5 supported by the rear end wall 11.
[0041] The drive unit 9 rotates the two rotor shafts 5 in opposite directions. The direction of rotation of the rotor shafts 5 is such that the water-containing raw material fed in from the inlet 3 is fed between the two screws 7, 7.
[0042] In this embodiment, one screw 7 is driven directly by the drive device 9, and the other screw 7 is connected by a bevel gear 9g and rotated in the opposite direction. However, the drive method is not limited to this configuration.
[0043] A drain port 10 is provided in the rear end wall 11 for discharging water generated by pressing the water-containing raw material to the outside of the casing 2. This drain port 10 has an opening of a size that allows some of the water-containing raw material to pass through. The drain port 10 is preferably a circular hole, and its diameter is preferably 5 mm or more, and particularly preferably 10 mm or more.
[0044] In this embodiment, the drain port 10 is provided above the lowest point inside the casing 2 on the front surface of the rear end wall 11 (the intersection point where the front surface of the rear end wall 11 and the rearmost and lowest part of the inner surface of the casing 2 intersect). That is, the lowest point of the drain port 10 is located above the lowest point of the rear end wall 11. Preferably, the lowest point of the drain port 10 is located 5 mm or more, more preferably 10 mm or more, even more preferably 15 mm or more above the lowest point of the rear end wall 11, and preferably within a range of 200 mm or less, more preferably 100 mm or less.
[0045] If the height of the drain port 10 is too high, the water level of the compressed water accumulated in the casing 2 will reach the lower edge of the discharge port 4, and water will be discharged from the discharge port 4 along with the water-containing raw material. Therefore, it is preferable that the level of the lower edge of the opening of the drain port 10 be lower than the level of the lower edge of the discharge port 4. The above applies when the axis is horizontal. It is also preferable to tilt the entire conical twin-screw extruder so that the tip of the axis is pointed somewhat upward.
[0046] The preferred positioning height of the drain outlet 10 depends on the size of the casing 2; a higher position is preferred when the casing 2 is large, and a lower position is preferred when the casing 2 is small or when the diameter of the water-containing raw material is small.
[0047] In conventional conical twin-screw extruders, the drain port is typically equipped with a wedge wire screen, a perforated plate, a mesh, or a cloth; however, in this embodiment, no such solid-liquid separation means is installed at the drain port 10.
[0048] The compression dewatering machine of this embodiment can be suitably used with screw diameters (rear end diameters) ranging from 100 mm to 500 mm.
[0049] In a conical twin-screw extruder configured in this way, the water-containing raw material (water-containing rubber wet masterbatch) is fed in through the inlet 3 and transported toward the discharge port 4 while being compressed by the screw 7. The water-containing raw material accumulated on the lower rear surface inside the casing 2 is scraped up by the flights 6 of the rotating conical screw 7 and compressed as it is transported forward within the casing 2. The compressed water flows backward along the slope of the lower surface of the casing 2 and is discharged from the drain port 10 on the rear end wall 11. In this way, the water-containing raw material can be efficiently dewatered by reversing the flow of the water produced by compression and the water-containing raw material.
[0050] In this embodiment, a seal ring 8 is provided at the rearmost part of the screw 7 (immediately in front of the front surface of the rear end wall 11). By not providing a flight behind the seal ring 8, the compressed water flows between the seal ring 8 and the front surface of the rear end wall 11 through the space between the outer circumference of the seal ring 8 and the lower inner surface of the casing 2. However, the water-containing rubber wet masterbatch and the compressed and dewatered rubber wet masterbatch hardly move behind the seal ring 8. Furthermore, even if fine water-containing rubber wet masterbatch or rubber wet masterbatch enters the space between the seal ring 8 and the rear end wall 11, there is no flight in this area, so it is not pressed against the seal ring and accumulates, but is discharged from the drain port 10 along with the water. As a result, clogging of the drain port 10 by water-containing rubber wet masterbatch or rubber wet masterbatch is prevented.
[0051] In this embodiment, by not providing a solid-liquid separation means at the drain port 10, blockage of the drain port 10 is more reliably prevented.
[0052] In this embodiment, because the inlet 3 is positioned forward of the seal ring 8, the water-containing raw material introduced into the casing 2 from the inlet 3 is prevented from directly entering the space between the seal ring 8 and the rear end wall 11 and reaching the drain port 10, thereby enabling efficient dewatering of the water-containing raw material.
[0053] In one aspect of the present invention, the distance between the rear end of the inlet 3 and the front surface of the seal ring 8 is such that, for a flight 6 having N strands, there is enough space for a 360 / N° screw flight to exist between the rear end of the inlet 3 and the front surface of the seal ring 8. This ensures that the water-containing raw material comes into contact with the screw flight and is transported to the discharge port 3 before reaching the drain port. The number of strands in N refers to the number of helices constituting the screw flight being N sets.
[0054] In the embodiments shown in Figures 1 and 2, the drain port 10 is provided on the rear end wall 11, but it may also be provided on the casing 2. An example of such a compression dewatering machine 1' is shown in Figures 3 to 5.
[0055] In this compression dewatering machine 1', drain ports 10', 10' are provided on the lower rear surface of the casing 2, slightly above the lowest part of the casing 2. As shown in Figure 5, in a cross section perpendicular to the axis X of the rotor shaft 5 and including the drain port 10', if P is the intersection point between the downward-sloping surface V, which is drawn vertically downward from the axis X of the rotor shaft 5, and the inner surface of the casing 2, then the drain port 10' is located above the intersection point P.
[0056] In Figure 5, h indicates the difference in height within the cross-section between the intersection P and the inner peripheral edge E on the intersection P side of the drain outlet 10'.
[0057] The distance between the rear edge of the drain port 10' on the inner surface of the casing 2 and the front surface of the rear end wall 11 is preferably 1 mm or more, and particularly preferably 3 mm or more. Also, the front edge of the drain port 10' is located behind the rear edge of the inlet port 3. In this way, by not having a drain port below the inlet port 3, it is possible to prevent the problem of watery raw material flowing directly into the drain port and blocking it when watery raw material is introduced. Furthermore, since the watery raw material moves along the bottom surface of the casing 2 in the direction of the rotor shaft 5, in this invention, a drain port is not provided on the bottom surface of the casing 2 at a position vertically below the axis of the rotor shaft 5, even if not at the very bottom of the casing 2.
[0058] The preferred size of the drain opening 10' is the same as the preferred size of the drain opening 10. The drain opening 10' is located behind the seal ring 8.
[0059] In this embodiment as well, it is preferable to provide the drain port 10' such that its lowest end (near the inner peripheral edge E of the drain port 10' on the inner surface of the casing 2) is located preferably 5 mm or more, more preferably 10 mm or more, and even more preferably 15 mm or more above the lowest end of the rear end wall 11 (the part where the front surface of the rear end wall 11 and the rearmost and lowest part of the inner surface of the casing 2 intersect), and preferably 200 mm or less, more preferably 100 mm or less. This ensures that water-containing raw materials with a high specific gravity sink into the compressed water, and only the compressed water is selectively discharged from the drain port 10'.
[0060] The other components of this dewatering press 1' are the same as those of the dewatering press 1, and other reference numerals in Figures 3 and 4 indicate the same parts as in Figures 1 and 2.
[0061] Figure 3 is a longitudinal cross-sectional view of the same section as in Figure 1, and Figure 4 is a horizontal cross-sectional view of the same section as in Figure 2. In Figures 3 and 4, screws 6 and 7 are shown with a portion of the base end cut out to clearly indicate the drain port 10', but the actual screws 6 and 7 do not have such a cutout. The actual shape of screws 6 and 7 in Figures 3 and 4 is the same as that of screws 6 and 7 in Figures 1 and 2.
[0062] [Water-containing raw materials] The rubber component of the hydrated rubber wet masterbatch used in the present invention is not particularly limited, but examples include solution-polymerized SBR (styrene-butadiene rubber), emulsion-polymerized SBR, and natural rubber. As the hydrated raw material, compositions of rubber components, carbon black, antioxidants, oils and fats, and other components are preferably used. Other components are not particularly limited, but examples include silica, carbon nanotubes, carbon nanofibers, graphene, cellulose, and cellulose nanofibers. The specific gravity of the hydrated raw material is preferably greater than 1.0, more preferably 1.05 or higher, and even more preferably 1.1 or higher, because it facilitates separation from water (pressed water). The size of the hydrated raw material is not particularly limited, but is usually spherical with a diameter of 1 to 50 mm, particularly 1 to 10 mm.
[0063] The moisture content of the water-containing rubber wet masterbatch is preferably 10% by weight or more, particularly 20% by weight or more, and 70% by weight or less, particularly 50% by weight or less, but is not limited thereto. The moisture content of the rubber wet masterbatch after dewatering by pressing is preferably 10% by weight or less, particularly 5% by weight or less. [Explanation of Symbols]
[0064] 1.1' Compression and dehydration machine 2 Casing 3 Inlet 4 outlet 5. Rotor shaft 6 Flights 7 Screw 8 sealing rings 9. Drive unit 10,10' drain 11 Back end wall
Claims
1. A casing having a discharge port for kneaded material at the front and an input port for water-containing raw materials on the upper surface of the rear, A rear end wall provided at the rear end of the casing, Two conical screws are installed inside the casing, A drainage port provided on the rear end wall or the lower surface of the rear of the casing and A press dewatering machine for a water-containing rubber wet masterbatch, having the following features: The screw comprises a rotor shaft, helical flights rising from the outer surface of the rotor shaft, and a seal ring rising from the rotor shaft behind the flights. The aforementioned loading port is located above the flight, A press dewatering machine for a water-containing rubber wet masterbatch, wherein the drain port is located behind the seal ring, and the lowest end of the drain port is positioned above the lowest end inside the casing.
2. The water-containing rubber wet masterbatch pressing and dewatering machine according to claim 1, characterized in that the drain port is provided in the rear end wall.
3. The water-containing rubber wet masterbatch pressing dewatering machine according to claim 2, characterized in that the drain port is located in a range of 5 to 200 mm above the point where the inner surface of the rear end wall and the rearmost and lowest part of the inner surface of the casing intersect.
4. The water-containing rubber wet masterbatch pressing dewatering machine according to claim 1, characterized in that the drain port is provided on the lower surface of the rear of the casing.
5. The water-containing rubber wet masterbatch pressing dewatering machine according to claim 1, characterized in that the lower part of the inner surface of the casing has an upward slope from the rear end wall toward the discharge port.
6. The water-containing rubber wet masterbatch compression dewatering machine according to claim 1, characterized in that the drain port is not provided with a solid-liquid separation means.
7. A method for producing a rubber wet masterbatch, comprising the step of dewatering a water-containing rubber wet masterbatch using a water-containing rubber wet masterbatch press dewatering machine described in any one of claims 1 to 6.