JP2001070775A - Mixing machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To uniformize a rubber plasticity and a dispersibility of an additive, thereby shortening a kneading time as well as enhancing operating property. SOLUTION: A mixing machine is provided with a first and a second bodies 6 and 21 arranged for the first and the second opening parts 2 and 20 in a mixing chamber 3. A rubber flow part 14 comprised of push-fit parts 13 and 26 extending to the length direction and protruding towards the approximate intermediate position of the rotor axis and an escape part 14 equipped at the both sides of the push-fit parts 13 and 26 is formed on substrates 12 and 25 capable of closing the opening parts 2 and 20 of at least one of the first and the second cover bodies 6 and 21.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mixer capable of shortening the kneading time of rubber and plastic materials and improving the operability of the apparatus.

[0002]

2. Description of the Related Art In order to impart desired physical properties to a vulcanized rubber material, it is necessary to knead the rubber material by cutting the rubber molecules to plasticize the raw rubber and uniformly disperse the additives. Closed mixers are frequently used.

As shown in FIG. 9 (A), the mixer a has a mixing chamber b having a first opening b1 into which a raw rubber g to be kneaded and an additive are charged. In the mixing chamber b, a pair of screw shaft-shaped rotor shafts c is provided, and a weight-shaped first cover d1 (so-called floating weight) for closing the opening is provided in the first opening b1. It is arranged to be able to move up and down. Kneading is performed by rotating the rotor shafts c in opposite directions. Reference numeral b2 in the drawing denotes a second opening for taking out the kneaded mixture, and d2 denotes a stopper-shaped second cover (a so-called drop door) for closing the same.

Looking at the kneading process, a low-temperature raw material rubber g having long and solid rubber molecules is charged into a mixing chamber b, and then is ground between the rotor shafts c and c to form chips. It is finely sheared (shearing process). Thereafter, the fluidity increases with an increase in temperature, and the raw rubber g
(B) circulates in the direction of arrow f, that is, the raw rubber g is wound around each rotor shaft c and moves in the axial direction, and at the outer end of the rotor shaft c, sequentially moves to the next rotor shaft side, Dispersion of the additives takes place (flow process).

[0005] At this time, in the above-mentioned shearing process, conventionally, in order to increase the shearing efficiency by pushing the raw rubber g between the rotor shafts c, a pressurized state in which the first covering body d1 (floating weight) is pushed down. The rotor shaft c is driven (shown by a dashed line in FIG. 9A) to shorten the plasticization time. For this reason, the first cover body d1 (floating weight) has a push-in portion e protruding substantially in a V-shape on the lower surface thereof.
Is provided over the entire length in the axial direction. Similarly, a substantially V-shaped push-in portion e projects from the upper surface of the second cover d2 (drop door).

On the other hand, in the flow process,
When the first cover d1 (floating weight) is pushed down, the pushed-in portion e acts as a wall between the rotor shafts c and c to prevent rubber transfer between the rotor shafts c and c. Smooth flow is impaired, and the dispersing effect of the additive is reduced.

Therefore, conventionally, the first cover d1
(Floating weight) pushed up (Fig. 9
(The solid line is shown in (A)), and the flow process is performed.

[0008]

However, in such a conventional method, since the flow process is carried out in a non-pressurized state, flow unevenness such as partial lifting of the raw rubber g from the rotor shaft c causes plasticity. In addition, this causes non-uniform dispersibility of the additives. In addition, operability is impaired, such as the need to push up the first cover d1 (floating weight) between the shearing process and the flow process.

Accordingly, the present invention is based on the fact that at least one of the first and second cover bodies is formed with a relief portion having a height lower than that of the pushed-in portion by removing both sides of the pushed-in portion. The rubber can flow smoothly while maintaining the pressurized state, the plasticity of the rubber and the dispersibility of the additives can be made uniform, the kneading time can be shortened, and the operation of pushing up the first cover body during operation is unnecessary. It is intended to provide a mixer capable of improving operability.

[0010]

According to a first aspect of the present invention, there is provided a mixer according to the first aspect of the present invention, wherein a first opening for introducing a material to be kneaded and a second opening for removing the kneaded material are provided. A mixer body having a mixing chamber having an opening formed therein, two parallel rotor shafts arranged in the mixing chamber and having screw blades for kneading, and a second closing the first and second openings. A first cover and a second cover;
At least one of the covering members is provided on a base capable of closing the opening, and has a projecting shape protruding toward a substantially intermediate position between two rotor shafts between both side edges of the base and extending in a longitudinal direction of the rotor shaft. It is characterized in that a rubber flowing portion comprising a pushing portion and a relief portion provided on both sides of the pushing portion and having a height smaller than that of the pushing portion is formed.

Further, in the invention according to claim 2, the rubber flow portion is provided on both the first and second covers.

According to a third aspect of the present invention, in the first cover, the pushed-in portion of the rubber flowing portion has a length of 30 to 50% of the length of the base.

According to a fourth aspect of the present invention, in the second cover, the pushing portion of the rubber flowing portion has a length of 50 to 80% of the length of the base.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. In FIG. 1, a mixer 1 includes a mixer main body 4 having a mixing chamber 3 having a first opening 2 into which a material to be kneaded is charged and a second opening 20 to take out the kneaded material. It comprises two parallel rotor shafts (5L, 5R) arranged in the mixing chamber (3) and first and second covers (6, 21) capable of closing the first and second openings (2, 20).

The material to be kneaded contains, for example, a basic material such as raw rubber and a powdery additive such as carbon and sulfur. The material to be kneaded is subjected to a shearing action, a rolling action and the like by rotation of the rotor shafts 5L and 5R. It is kneaded.

The mixer body 4 is, as shown in FIG.
The mixing chamber 3 is formed in a block shape having a mixing chamber 3 therein, and the mixing chamber 3 is formed in a substantially cocoon shape in which two cylindrical spaces H having the same diameter are overlapped and arranged in parallel. That is, the mixing chamber 3 has upper and lower substantially triangular protrusions 7U and 7L in which the inner wall surfaces Hs of the cylindrical spaces H protrude inward at the center in the juxtaposition direction.

The first opening 2 is formed by opening the upper protruding portion 7U, and the second opening 20 is formed by opening the lower protruding portion 7L. I have. In the present example, the first and second openings 2, 20 are formed over substantially the entire width of each of the projections 7U, 7L, so that substantially the entirety of the projections 7U, 7L is cut off. Although the case of such a configuration is illustrated, it may be formed narrower than the protruding portions 7U and 7L, that is, leaving a part of the protruding portions 7U and 7L.

The length L1 of the first opening 2 in the longitudinal direction F of the rotor shaft is 90 to 90 times the length L2 of the mixing chamber 3.
If it is 100% and less than 90%, the material to be kneaded is difficult to spread over the entire mixing chamber 3 and may cause air to remain or impair the kneading efficiency. Therefore, it is preferable to be closer to 100%.

Next, the rotor shafts 5L and 5R are shown in FIGS.
As shown in FIG. 2, the mixer body 4 is rotatably supported on the mixer body 4 via, for example, a well-known bearing means 9 (not shown in FIG. 2), and a spiral shaft formed around the shaft 10. And a screw wing 11 of the above. Each rotor shaft 5L,
5R is a well-known drive / conduction means (not shown) which is arranged concentrically with the cylindrical spaces H, H and includes a motor.
Are driven to rotate in directions opposite to each other.

In this embodiment, the screw blade 11 extends continuously from one end of the base shaft 10 to the other end. However, a discontinuous portion may be provided in the middle. The direction of the spiral, the pitch of the spiral, and the like can be different between the one wing portion and the other wing portion divided by the break.

In this embodiment, for convenience, the rotor shaft 5
Pitch circle EL of each screw wing 11 of L, 5R,
Although the tangent type ER is illustrated as being close to each other, a meshing type in which the pitch circles EL and ER overlap may be used, and further, a double wing type in which a plurality of screw wing portions 11 are provided. Various known rotor shaft configurations can be employed. Alternatively, the clearance between the rotor shafts 5L and 5R may be changed in the axial direction to enhance the dispersion effect.

The present invention is characterized in that a rubber flowing portion 19 is formed on at least one of the first and second cover members 6 and 21. In this example, the case where the rubber flow portion 19 is formed on the first cover 6 which is a so-called floating weight is illustrated.

That is, as shown in FIG. 3, the first cover 6 is a base 12 capable of closing the first opening 2.
A protruding push-in portion 13 and relief portions 14, 14 provided on both sides thereof and having a height less than that of the push-in portion 13.
Is formed.

The base 12 has a block shape with a rectangular cross section substantially the same as the opening shape of the first opening 2.
For example, it is attached to the lower end of the rod 15 of the lifting means such as a cylinder so as to be able to move up and down. The mixer body 4 has a guide path 16 having a lower end connected to the first opening 2 and an upper end provided with an inlet (not shown) for the material to be kneaded. The base 12 is guided up and down via a path 16.

The pushing portion 13 has a protruding shape protruding downward toward a substantially intermediate position between the rotor shafts 5L, 5R between the side edges 12e, 12e of the base 12, and extends in the longitudinal direction F. Is done. The push-in portion 13 preferably has a substantially triangular cross section substantially the same shape as the protrusion 7U,
In this example, the case where the hypotenuse 13A is formed by, for example, a concave arc having the same diameter as the inner wall surface Hs of the mixing chamber 3 is illustrated. Note that the hypotenuse 13A may be formed as a straight line.

The relief portion 14 is provided with the pushing portion 1.
3 is smaller than FIG. 3, and in FIG.
An example is shown in which the relief portion 14 is formed by cutting along the entire height with a plane 22 substantially parallel to the lower surface of the base 12.

The escape portion 14 is formed by cutting the pushing portion 13 obliquely by a slope 23 as shown in FIG. 4, or the tip of the pushing portion 13 as shown in FIG. Various shapes such as those formed by cutting the side by a plane 22, and those formed by cutting the press-in portion 13 by a plane 22 together with a part of the base 12 as shown in FIG. 6. Can be formed. Instead of the flat surface 22 and the inclined surface 23, a smooth arc surface having a large radius of curvature may be used.

Here, as in the present embodiment, the first cover 6
In the case where the rubber flowing portion 19 is formed only on the base, the pushing portion 13 preferably has a length L4 of 30 to 50% of the length L3 of the base. If it exceeds 50%, it is not possible to sufficiently exert the effect of smoothing the flow, such as the resistance of the material to be kneaded moving between the rotor shafts 5L and 5R in the flow process. On the other hand, if it is less than 30%, in the shearing process, the material to be kneaded is removed from the rotor shafts 5L, 5R.
There is a possibility that the effect of pushing into the space is reduced and the kneading time is prolonged.

The second cover 21 which is a so-called drop door is, as shown in FIG.
A push-in portion 26 projects over the substantially entire length of the upper surface of the base 25 that can close the second opening 20.

The base 25 has a rectangular block shape having substantially the same shape as the opening of the second opening 20, and the second opening 20 is supported so as to be openable and closable. The pushing portion 26 is, similarly to the pushing portion 13, provided with the rotor shafts 5L, 5R between the side edges 25e, 25e of the base 25.
Is formed in a protruding shape protruding upward toward a substantially intermediate position, and is preferably formed in a substantially triangular cross section having substantially the same shape as the protruding portion 7L. Although the hypotenuse 26A is formed by a concave arc having the same diameter as the inner wall surface Hs in this example, the hypotenuse 26A may be formed by a straight line.

Next, another embodiment of the mixer 1 in which the rubber flowing portion 19 is formed only on the second cover 21 will be described with reference to FIG.
An example is shown below.

In the figure, the first cover 6 is provided on a lower surface of the base 12 with a pushing portion 13 over substantially the entire length thereof.
Is protruding. The second cover 21 has a rubber flow portion 19 on the upper surface of the base body 25, which includes the pushing portion 26 and relief portions 27 provided on both sides thereof and having a height smaller than that of the pushing portion 26. Is formed.

The relief portion 27 can be formed in various shapes similar to the relief portion 14 illustrated in FIGS.

When the rubber flowing portion 19 is formed only on the second cover 21, the length L6 of the pushing portion 26 is set to 50 to 80 of the length L5 of the base 25 for the same reason. % Is preferable. If it exceeds 80%, the effect of smoothing the flow cannot be sufficiently exerted.
The effect of pushing between L and 5R is reduced, which tends to prolong the kneading time.

As shown in FIG. 8, rubber flow portions 19 can be provided on both the first and second cover members 6 and 21.

Thus, for example, the raw rubber and the additive are charged into the mixing chamber 3 through the guide path 16 and the first opening 2, while the first cover 6 is lowered by the extension of the rod 15. Then, the first opening 2 is closed and the inside of the mixing chamber 3 is pressurized at a predetermined pressure.

In this pressurized state, the rotor shafts 5L, 5R are driven to rotate in opposite directions. At this time, as long as the raw rubber is in a solid state or has a high viscosity and is not plasticized, the raw rubber is pushed between the rotor shafts 5L and 5R by the pushing portions 13 and 26, as in the conventional case, and the plasticized plastic is formed. Is promoted. In addition, since the material rubber is pressed down at the predetermined pressure also in the relief portion 14 and / or the relief portion 27, there is no escape of the chips at the time of chewing and the shearing action can be sufficiently exerted.

When plasticization proceeds and fluidity occurs,
The raw rubber circulates in the direction of arrow f as shown in FIG.
At this time, since the raw rubber is wound around each of the rotor shafts 5L and 5R and moves in the length direction F, the pushing portions 13 and 26 do not become a resistance to the movement.

The raw rubber which has moved to the outer ends of the rotor shafts 5L, 5R is supplied to the relief portion 14 and / or the relief portion 2.
7, the transition to the adjacent rotor shaft side does not hinder the transition, and a smooth flow along the arrow f can be performed. In addition, since the first cover 6 pressurizes during the flow process, the flow unevenness such as the raw rubber being partially lifted from the rotor shafts 5L and 5R can be suppressed. As a result, the effect of dispersing the additive is enhanced, and more uniform dispersion can be performed within a shorter time.

In addition, the operability can be improved, for example, by eliminating the need to push up the first cover 6 as in the conventional case.

When a conventional mixer was used to knead a rubber compounded with 50 phr of an additive (carbon black), it took 2.5 minutes. It was confirmed that the kneading time was reduced by about 8%, for example, rubber having the same degree of dispersion could be obtained in 2.3 minutes.

[0042]

As described above, according to the present invention, since at least one of the first and second covering members is provided with a rubber flowing portion having relief portions formed on both sides of the pushing portion, the pressurized state is maintained. While the rubber can flow smoothly, the plasticity of the rubber and the dispersibility of the additives can be made uniform, and the kneading time can be shortened. In addition, operability can be improved, for example, by eliminating the need to push up the cover during operation.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a main part of a mixer according to one embodiment of the present invention.

FIG. 2 is a cross-sectional view thereof.

FIG. 3 is an exploded perspective view showing a mixer body and a cover.

FIG. 4 is a perspective view showing another embodiment of the cover.

FIG. 5 is a perspective view showing still another embodiment of the cover.

FIG. 6 is a perspective view showing still another embodiment of the cover.

FIG. 7 is an exploded perspective view showing another embodiment of the mixer.

FIG. 8 is an exploded perspective view showing still another embodiment of the mixer.

FIGS. 9A and 9B are a longitudinal sectional view and a transverse sectional view illustrating a conventional mixer.

[Explanation of symbols]

 2, 20 First and second openings 3 Mixing chamber 4 Mixer main body 5L, 5R Rotor shaft 6, 21 First and second cover 11 Screw wing 12, 25 Base 13, 26 Push-in part 14, 27 Evacuation part 19 Rubber flow part

Claims (4)

[Claims] 1. A mixer main body having a mixing chamber having a first opening into which a material to be kneaded is introduced and a second opening to take out a kneaded material to be kneaded; Two parallel rotor shafts having screw wings, and first and second covering members for closing the first and second openings. At least one of the bases capable of closing the opening, a protruding push-up portion protruding toward a substantially intermediate position between the two rotor shafts between both side edges of the base and extending in the longitudinal direction of the rotor shafts, A mixing machine characterized by forming a rubber flowing portion comprising a relief portion provided on both sides thereof and having a height smaller than that of the pushing portion. 2. The mixer according to claim 1, wherein said rubber flow section is provided on first and second covers. 3. The mixer according to claim 1, wherein the first cover has a pressing portion of the rubber flowing portion having a length of 30 to 50% of a length of the base. 4. The mixer according to claim 1, wherein said second covering body has a pressing portion of said rubber flowing portion having a length of 50 to 80% of a length of said base.