JPH0911229A - Hermetically closed kneading apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain homogenous kneading without reducing rubber housing vol. by spirally extending respective rotors around the center axes thereof and providing long blades to each of the rotors having an almost triangular cross-sectional shape in the circumferential direction thereof at an equal angle interval. SOLUTION: Each of rotors 3, 4 has three long blades 18, 19, 20 arranged in the circumferential direction thereof at an equal 120 deg.-interval. The apexes of the respective long blades 18, 19, 20 of each of the rotors having an almost triangular cross-sectional shape become tips 21 keeping a predetermined interval with respect to the inner wall of a chamber 2. The area from the end 18a of the tip 21 of the long blade 18 to the end 19a of the tip 21 of the long blade 19 is the back surface 26 in a rotary direction on the basis of the tip 21 of the long blade 18 and divided into the counteraction surface 22 to the tip 21 of the long blade 18 and the action surface 23 to the tip 21 of the long blade 19 and the action surface 23 is a sump part for guiding kneaded matter to the tip 21 and usually formed into a protruding curved surface.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a batch-type closed kneading apparatus suitable for kneading a rubber-like material, which has improved productivity.

[0002]

2. Description of the Related Art Generally, a rubber used for a tire or the like is a mixture of raw rubber and sulfur, carbon, and additives such as a filler. A closed kneader is used for mixing the raw rubber and the additive, and the closed kneader lowers the plasticity of the rubber and makes the dispersion of the additive uniform. By the way, since rubber used for a radial tire of an automobile is hard, it is difficult to uniformly disperse the additive as compared with ordinary rubber.

[0003] Therefore, as a closed kneading apparatus capable of uniformly dispersing additives, those disclosed in Japanese Patent Publication Nos. 58-4567 and 58-5094 are used.

In the hermetic kneading apparatuses disclosed in these publications, a pair of counter-rotating rotors are arranged in parallel in a non-meshing manner in a closed chamber with a cross section of a cocoon shape. As with the long wings, 2 at equal circumferential angles
It has a total of four wings consisting of a plurality of short wings, and the wing length ratio, thrust ratio, and the like of the long wing and the short wing are appropriately set. That is, the kneading function is improved by increasing the total number of blades from two to four.

[0005] In recent years, in order to improve the quality of tires, the hardness of rubber has become higher and the degree of dispersion by kneading has been required more severely. Then, even in the above-described four-bladed rotor, the additives are not uniformly dispersed during the predetermined kneading time, and long-time kneading is required. If kneading is performed for a long time, the temperature of the rubber to be kneaded rises, and deterioration such as a vulcanization reaction occurs. Therefore, when the temperature of the rubber has risen to a certain degree, it has been necessary to carry out kneading a plurality of times, such as once taking out the rubber from the chamber, cooling it, and kneading the cooled rubber again. When the kneading is performed a plurality of times, the productivity of the closed kneading device per unit time is significantly reduced.

[0006] Japanese Patent Application Laid-Open No. 63-47107 (US Pat. No. 4,871,259) discloses a closed type kneading apparatus for reducing the number of times of kneading a plurality of times or improving kneading performance.
Has been proposed. In this closed type kneading device, a pair of counter-rotating rotors are arranged in parallel in a closed chamber having a cocoon-shaped cross section, and each rotor is continuous with three long blades at equal angles in the circumferential direction. It has three short blades, and in order to increase the accommodation volume of rubber, the cutting angle at which the back surface in the rotational direction of each blade and the tangent line at the radially outer end of each blade is set to 40 degrees or more and 140 degrees or less. It is a thing. In order to prevent stagnation of the material at the cut existing on the reaction surface on the back side in the rotation direction, the central axes of the pair of rotors are narrowed so that the blades mesh with each other, and the long blade and the short blade are formed as continuous blades. ing.

[0007]

However, in the above-mentioned closed kneading apparatus using a rotor having three long blades and a notch at equal angles in the circumferential direction, the distance between the center axes of the rotors is reduced. In order to engage with each other, the volume in the chamber was reduced, and the increase in the rubber storage volume due to the cut was limited. The reduction in the rubber storage volume was inevitable as compared with the one having two long blades. In addition, if the cut is deepened in order to reduce the reduction of the rubber accommodation volume, there is a problem that free carbon is likely to be generated due to the retention of the rubber in this portion.

[0008] The inventions of claims 1 to 3 have been made in view of such problems of the prior art, and an object thereof is to provide three long blades at equal angles in the circumferential direction. It is an object of the present invention to provide a closed kneading apparatus capable of obtaining a homogeneous kneading without reducing a rubber accommodation volume by disposing a pair of rotors having no engagement.

[0009]

The invention according to claim 1 of the present invention which achieves the above object, comprises: a case member forming a closed chamber having a cocoon-shaped cross section; and a case member arranged in parallel in the chamber in a reverse direction. In a closed-type kneading device including a pair of rotating rotors, each rotor has three long blades extending spirally around a central axis at equal angles in the circumferential direction, and the central axis of each rotor is the long blade. Are separated from each other so as not to mesh with each other, and the rotor cross-sectional shape of the long blade portion corresponds to at least one of the following (a) to (d). (A) The cross-sectional shape of the rotor is substantially triangular. (B) In the rotor cross-section, the reaction surface on the back side in the rotation direction includes a straight line starting from the end of the blade tip. (C) When the back surface in the rotation direction of the rotor cross-sectional shape is formed by one smooth concave approximation, convex approximation, or linear approximation curved surface, and the maximum diameter of the rotor cross-section shape is Dr and the minimum diameter is Dd, It is within the range of 0.5 <Dd / Dr <0.75. (D) When the back surface in the rotational direction of the rotor cross-sectional shape is formed by one smooth concave approximation, convex approximation, or linear approximation curved surface, and the maximum diameter of the rotor cross-sectional shape is Dr and the minimum diameter is Dd, It falls within the range of 0.6 <Dd / Dr <0.70.

When the number of long blades becomes three, the surface area of the rotor increases, so that the kneaded material is cooled and the kneading time can be lengthened.
If the center axes of the rotors are separated from each other so that the long blades do not engage with each other, the volume in the chamber does not decrease. Because of the non-meshing rotor, it is necessary to take in sufficient kneaded material on the working surface in the direction of rotation of the rotor as viewed from the blade tip, of the rotor cross-sectional shape. Of particular importance is the shape of the reaction surface on the rear side in the rotational direction (the surface in the anti-rotation direction of the rotor when viewed from the blade tip). It has been experimentally confirmed that, when the reaction surface is formed into a normal convex shape or, conversely, a concave shape, the kneaded material taken in front of the working surface is reduced. In particular,
It is necessary to have a relatively flat reaction surface that satisfies at least one of the above (a) and (b). Here, the reaction surface is defined as the tip of the tip of the tip of the blade of the blade in the rotation direction, which is opposite to the tip of the blade in the direction of rotation (opposite to the rotation direction). It refers to a plane that exists between points that are separated in the rotation direction.

According to a second aspect of the present invention, in the first aspect of the present invention, the rotor has three short blades having a cross section similar to the rotor cross section of the long blade portion. The short wing is discontinuous.

If the long blades and the short blades are discontinuous, an active flow of the kneaded material in the chamber occurs in the chamber, so that the dispersion of the degree of dispersion in the chamber is reduced.

According to a third aspect of the present invention, in the second aspect of the invention, the rotor blade length ratio of the discontinuous blade is in the range of 0.1 to 0.67.

[0014] When the blade length ratio of the short blades to the long blades of the discontinuous blades is 0.1 to 0.67, the axial flow in the chamber is surely generated. Variation is reduced.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view of a main part of a closed kneading apparatus, and FIG. 2 is a developed view of a rotor.

In FIG. 1, the case member 1 includes a casing 13 having a floating weight 11 and a drop door 12, and end plates (not shown) provided at both ends of the casing 13 in the thickness direction of the drawing. Inside the case member 1, a chamber 2 having a cross-sectional eyebrows type as shown in the figure is formed. The shape of the cross section of the chamber 2 is a bridge 1 as a communicating part with the left chamber 14 and the right chamber 15.
6 A pair of left and right rotors 3 and 4 have a central shaft 17.
It is rotatably supported at a and 17b. Center shaft 17a, 1
7b is larger than the maximum diameter Dr of the rotors 3 and 4, the rotors 3 and 4 are not engaged with each other and the arrows a and b shown
Rotate in the opposite direction. The rubber-like material is put into the chamber 2 by pushing the floating weight 11, kneaded by the rotors 3 and 4, and then discharged by opening the drop door 12.

As shown in the figure, the rotors 3 and 4 are
It has three long wings 18, 19, 20 which are equally spaced at 20 degrees. The top of each of the long blades 18, 19, and 20 is a chip 21 that maintains a predetermined distance from the inner wall of the chamber 2. From the end 18a of the tip 21 of the long wing 18 to the end 19a of the tip 21 of the long wing 19, the tip 21 of the long wing 18
, And is divided into a reaction surface 22 for the tip 21 of the long wing 18 and an operation surface 23 for the tip 21 of the long wing 19. Working surface 23
Is a pool portion for guiding the kneaded material to the chip 21,
Usually, it is formed with a convex curved surface. Reaction surface 22 is bridge 1
This is a part that plays an important role in taking in the six parts of the kneaded material on the working surface side, and is a straight line starting from the end 18a of the tip 21 of the long wing 18. Since the reaction surface 22 is longer than the operation surface 23, the whole of the rotors 3 and 4 has a substantially triangular shape, and a rotational saw tooth shape as shown in FIG.
Is clearly distinguished from the plump shape.

FIG. 2 shows a developed shape of the rotors 3 and 4. The long blades 18, 19, and 20 at every 120 degrees in the circumferential direction spirally extend from one axial end of the rotors 3 and 4 at an inclination angle θ so as to move the kneaded material toward the center of the rotors 3 and 4. Is interrupted on the way. The breaks 18b, 19
Short wings 30, 31, and 32 are provided extending from b and 20b to the other axial ends of the rotors 3 and 4. Long wing 1
Since the 8, 19, 20 and the short blades 30, 31, 32 are discontinuous, the kneaded material moves while meandering in the direction of the rotor axis as shown by the arrow c. The discontinuous portions 18b, 19b, 20b of the long wings 18, 19, 20 and the discontinuous portions 30b, 31b, 32b of the short wings 30, 31, 32 are arranged in a line in the circumferential direction. When the short wings 30, 31, and 32 are extended to form an overlap portion, the number of wings at the overlap portion increases, so that the kneading function further increases. In addition, the overlapping portions and the broken portions 18b, 19b, 20b, 30b, 31b, 32b of the long and short blades.
However, the cross-sectional shape of the rotor in the portion arranged in the circumferential direction is a shape approximating a hexagon. That is, the rotor cross-sectional shape in FIG. 1 shows a cross section of only the long blades 18, 19, 20 and the short blades 30, 31, 32.

[0019]

Next, an experimental example relating to the performance of the closed kneading apparatus described in FIG. 1 will be described below. The performance of the non-meshing 6 blade rotors 3 and 4 as shown in FIG.
The description will be made in comparison with the blade rotors 51 and 52. As shown in FIG. 3, the non-meshing four-blade rotors 51 and 52 used in the experiment have convex shapes on both the working surface and the reaction surface, and have an oval cross section as a whole. A two-dimensional testing machine was used for the experiment,
After kneading with the same rotation speed and the same amount of input material for the same time, both material temperatures were measured.

As shown in the graph of FIG. 3, it can be seen that the material temperatures at the end of kneading vary considerably, and that the six-bladed rotors 3 and 4 have a higher cooling capacity than the four-bladed rotors 51 and 52. Also, as shown in FIG. 4, the degree of plasticization indicated by the Mooney viscosity reduction efficiency is higher for the six-bladed rotors 3 and 4 than for the four-blade rotors 51 and 52, and for the six-bladed rotors 3 and 4, the plastic surface is higher. It can be seen that the kneading function is excellent.

Further, a six-blade rotor and a four-blade rotor were compared in a three-dimensional test using a rotor as shown in FIG. A 6-blade rotor having a circumferential shift angle α = 60 ° of the long and short blades and a blade length ratio of 0.1,
FIG. 5 shows an experimental example comparing the distribution performance of a long-short blade with a 4-blade rotor having a circumferential deviation angle α = 90 ° and a blade length ratio of 0.2. According to FIG. 5, the distribution performance indicated by the dispersion of the degree of dispersion throughout the chamber is higher for the six-bladed rotor than for the four-bladed rotor, and it is understood that the six-bladed rotor has a better kneading function on the distribution surface.

Next, the influence of the shape of the reaction surface of the rotor exerted will be described with reference to the rotor shape of FIG. 1 and FIGS. 6 (first comparative example) and FIG.
A description will be given in comparison with the rotor shape of the second comparative example.
Note that the two-dimensional testing machine described above was used for the experiment.

In the rotors 61 and 62 of FIG. 6 (first comparative example), the portion from the tip end to the tip end on the back surface 67 in the rotational direction is substantially equally divided into the reaction surface 63 and the operation surface 64, and the reaction surface 63 is recessed. The working surface 64 is formed in a convex shape. In the rotors 71 and 72 in FIG. 7 (second comparative example), the portion from the tip end to the tip end on the back surface 76 in the rotation direction is substantially equally divided into a reaction surface 73 and an operation surface 74, and the reaction surface 73 is made convex. The working surface 74 is also made convex.

The concave reaction surface 6 shown in FIG. 6 (first comparative example)
In the rotors 61 and 62 of No. 3, relatively large voids are generated, such as the void 65 on the reaction surface of the rotor 62 and the void 66 near the bridge 16. This means that the amount of material taken into the working surface from near the bridge 16 is reduced. Further, generation of free carbon, which is assumed to be caused by the void 65 on the reaction surface, was confirmed.

The reaction surface 7 having a convex shape shown in FIG. 7 (second comparative example)
In the rotors 71 and 72 having the number 3, relatively large voids are generated like the void 75 near the bridge 16.
This means that the amount of material taken into the working surface from near the bridge 16 is reduced.

However, in the rotors 3 and 4 having the reaction surfaces 22 formed by the straight lines in FIG.
Although voids 25 are generated in the vicinity, the degree thereof is smaller than those in FIG. 6 (first comparative example) and FIG. 7 (second comparative example). This means that the material taken into the working surface from near the bridge 16 does not decrease so much.
That is, even if the rotors 3 and 4 are not meshed with each other, it is possible to ensure that the reaction surfaces of the rotors 3 and 4 have appropriate shapes so that the material can be taken into the working surface equivalent to the meshing state.

This is clearly shown by the difference in Mooney viscosity reduction efficiency based on the rotor shape difference in FIG. The Mooney viscosity reduction efficiency is improved in the order of the reaction surface shape of the straight line (example of the present invention), the convex shape (second comparative example), and the concave shape (first comparative example). That is, if the reaction surface shape on the back side in the rotational direction is a linear approximation and is rather flat, which is rather convex, the material taken in the operation surface increases, and the chance of kneading with the chip can be increased. .

The case where the reaction surface shape on the back side in the rotation direction of the rotor in FIG. 1 is a straight line or the whole rotor is substantially triangular has been described. In short, it is important that the reaction surface on the back side in the rotation direction of the rotor cross-sectional shape is formed by one smooth concave approximation, convex approximation, or linear approximation curved surface, and is smoothly connected to the convex shape of the operation surface. From this point of view, the results of verification of rotor shapes having reaction surfaces of various flatnesses will be described below.

As shown in FIG. 9, to define the flatness, the minimum diameter of the rotor cross-sectional shape is set to Dd, and the maximum diameter is set to Dr.
And the ratio of Dd / Dr was used. In the example shown,
The back surface in the rotational direction is formed by one smooth concave approximation, convex approximation, or linear approximation surface, and more than half and up to about 9/10 of the back surface in the rotation direction are reaction surfaces with high flatness, and the rest are convex shapes. Alternatively, it is a flat working surface. In this case, as shown, 0.5 <Dd / Dr <0.
75 is an allowable range, which is a range in which a clear difference in the degree of kneading from that of FIGS. 6 and 7 occurs. However, 0.6 <Dd / D
It is preferable to keep r <0.70 and make the reaction surface as close to a straight line as possible.

Since the above-mentioned test is mainly based on the result of the two-dimensional test, the result of examining the influence of the blade in the axial direction by the test using the three-dimensional shape will be described below. FIG.
As shown in FIG. 2, the result of the kneading test of the pseudo material in the case of the discontinuous wing of the long wing and the short wing is shown in the continuous wing (in FIG.
This will be described in comparison with the case where b is matched). FIG. 10 shows the results of 6 blades continuous or discontinuous, and FIG. 11 shows the results of 4 blades continuous or discontinuous. In any of the six blades and the four blades, the discontinuous blade has less variation in the degree of dispersion throughout the chamber than the continuous blade, and the discontinuous blade is superior to the continuous blade.

Further, as shown in FIG. 2, the influence of the blade length ratio between the long blade and the short blade, which is a discontinuous blade, is kneaded with the pseudo material when the blade length ratio is changed by using the 6-blade rotor shown in FIG. The test results will be described with reference to FIG. In FIG. 12, the smaller the blade length ratio, the better the distribution performance, but the blade length ratio is 0.
Even in the case of 67, the distribution performance can be used, and when the blade length ratio is less than 0.1, it is difficult to form the rotor morphologically. Therefore, the appropriate blade length ratio is 0.1 to 0.67. It is a range.

From the above description of the embodiment, it has been clarified that the six-blade long and short wing discontinuity of the sectional shape according to the present invention is excellent. This is explained with reference to FIGS. 13 and 14 because it is better and within the scope of the invention. First, the developed shape of the rotors 3 ', 4' having a continuous length of 6 blades and short blades used in the test is shown in FIG.
This will be described below. Continuous wing 18 'every 120 degrees in the circumferential direction,
Numerals 19 'and 20' extend helically from one axial end of the rotors 3 'and 4' at an inclination angle θ so as to move the kneaded material toward the inside of the rotors 3 'and 4'. ,
At 19b 'and 20b', they extend spirally at an inclination angle in the opposite direction to the ends. The spiral portion having the inclination angle θ is a long blade, and the reverse spiral portion is a short blade, and the blade length ratio between long and short is the same as that in FIG. For comparison with such a six-blade long and short continuous rotor, a four-blade long and short discontinuous rotor was used. In this four-blade long / short discontinuous rotor, the set of long and short blades in FIG. 2 is reduced by one to two sets, and two sets of long and short blades are arranged with a phase difference of 180 °.

FIG. 14 shows the degree of variation in the case of the above-mentioned four-bladed-short rotor and the six-bladed short-blade continuous rotor. As is clear from FIG. 14, when compared with the four-blade short-continuous rotor, not only the six-blade short-short rotor but also the six-blade short-continuous rotor have excellent characteristics. That is, it is important that the rotor has six blades and is a non-interlocking rotor having a predetermined cross-sectional shape as shown in FIG. 1. It is merely a difference of the embodiment.

[0034]

As described above, the first aspect of the present invention has three long blades which are not meshed with each other and are equiangular in the circumferential direction. By making the shape relatively flat, the cooling capacity was increased, the number of kneadings was reduced, and the decrease in the effective volume in the chamber was reduced as much as possible. There is an effect that the production efficiency can be improved as compared with a kneading apparatus using a three-bladed rotor. Further, there is an effect that the appearance of free carbon can be prevented, which is likely to occur in a continuous three-bladed rotor with a notched mesh.

According to the second aspect of the invention, in addition to the effect of the first aspect, since the long blades and the short blades are discontinuous, the degree of dispersion in the chamber becomes uniform, and the kneading quality can be improved. This has the effect.

According to a third aspect of the present invention, in addition to the effect of the second aspect, the long wing and the short wing are discontinuous and the length ratio of the long wing to the short wing is 0.1 to 0.67. In particular, the degree of dispersion in the axial direction becomes uniform, and the kneading quality can be further improved.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part of a closed kneading apparatus of the present invention.

FIG. 2 is a development view of a rotor of the device of the present invention.

FIG. 3 is a graph showing a material temperature at the end of kneading by a rotor of the apparatus of the present invention.

FIG. 4 is a graph showing Mooney viscosity reduction efficiency by a rotor of the apparatus of the present invention.

FIG. 5 is a graph showing the degree of dispersion in a chamber by a rotor of the apparatus of the present invention.

FIG. 6 is a sectional view of a main part of a closed kneading apparatus of a first comparative example.

FIG. 7 is a sectional view of a main part of a closed kneading apparatus of a second comparative example.

FIG. 8 is a graph showing Mooney viscosity reduction efficiencies according to the device of the present invention and first and second comparative examples.

FIG. 9 is a view showing another rotor shape of the device of the present invention.

FIG. 10 is a graph showing a degree of dispersion in a chamber by a rotor of the apparatus of the present invention.

FIG. 11 is a graph showing the degree of dispersion in a chamber by a four-bladed rotor.

FIG. 12 is a graph showing the degree of dispersion in a chamber of a device according to the present invention, particularly by a 6-blade short / short rotor.

FIG. 13 is a development view of a 6-blade long-short continuous rotor of the device of the present invention.

FIG. 14 is a graph showing the degree of dispersion in a chamber due to a 6-blade long / short continuous rotor of the apparatus of the present invention and a 4-blade short / short discontinuity of a comparative example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Case member 2 Chamber 3, 4 A pair of rotor 16 Bridge 17a, 17b Central axis 18, 19, 20 Long blade 21 Chip 22 Reaction surface 23 Working surface 26 Rotation back surface

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Yoshinori Kurokawa 2-3-1, Shinhama, Arai-cho, Takasago-shi, Hyogo Inside Kobe Steel, Ltd. Takasago Works

Claims (3)

[Claims] 1. A hermetic-type kneading apparatus comprising: a case member forming a hermetically closed chamber having a cocoon-shaped cross section; and a pair of rotors arranged in parallel in the chamber and rotating in opposite directions. There are three long blades that extend spirally around the axis at equal angles in the circumferential direction, the central axes of the rotors are separated from each other to the extent that the long blades do not mesh with each other, and the rotor cross-sectional shape of the long blade portion is (a) ) To (d), at least one of the closed type kneading apparatus is characterized. (A) The cross-sectional shape of the rotor is substantially triangular. (B) In the rotor cross-section, the reaction surface on the back side in the rotation direction includes a straight line starting from the end of the blade tip. (C) When the back surface in the rotation direction of the rotor cross-sectional shape is formed by one smooth concave approximation, convex approximation, or linear approximation curved surface, and the maximum diameter of the rotor cross-section shape is Dr and the minimum diameter is Dd, It is within the range of 0.5 <Dd / Dr <0.75. (D) When the back surface in the rotational direction of the rotor cross-sectional shape is formed by one smooth concave approximation, convex approximation, or linear approximation curved surface, and the maximum diameter of the rotor cross-sectional shape is Dr and the minimum diameter is Dd, It falls within the range of 0.6 <Dd / Dr <0.70. 2. The hermetic seal according to claim 1, wherein the rotor has three short blades having a cross section similar to the rotor cross section of the long blade portion, and the long blade and the short blade are discontinuous. Mold kneading device. 3. The long / short blade length ratio of the rotor is 0.1 to 10.
The closed type kneading device according to claim 2, wherein the range is 0.67.