Kneading apparatus

Abstract

The present invention suppresses heat generation of a material in a rotor capable of applying high stress to the material. A first outer peripheral part (50e) of a first rotor (50) comprises a first arc part (51) and a first non-arc part (53). The first arc part (51) continuously extends in the circumferential direction of the first rotor (50) by one third or more of the length of the entire circumference of a first virtual circle (50c). A second outer peripheral part (60e) of a second rotor (60) comprises a second arc part (61) and a second non-arc part (63). The second arc part (61) continuously extends in the circumferential direction of the second rotor (60) by one third or more of the length of the entire circumference of a second virtual circle (60c). At a predetermined timing, the first non-arc part (53) and the second arc part (61) face each other in a space (A) between a first rotating shaft (50a) and a second rotating shaft (60a).

Description

Mixing equipment

[0001] The present invention relates to a kneading device for kneading materials.

[0002] For example, a conventional kneading device is described in Patent Document 1. The kneading device described in this document has a rotor with blades.

[0003] Patent No. 4542605

[0004] When materials are mixed using a supercritical or subcritical working fluid, the viscosity of the material is lower than when mixed at atmospheric pressure. As a result, the stress that the mixer can apply to the material is reduced, which can lead to insufficient dispersion of the material. On the other hand, when using a conventional rotor that can apply high stress to the material, heat generation from the material can become a problem.

[0005] An object of the present invention is to provide a kneading device that can apply high stress to a material and suppress heat generation from the material.

[0006] A kneading device according to one aspect of the present invention comprises a kneading chamber that accommodates a material together with a working fluid in a supercritical or subcritical state in order to knead the material, a first rotor that is disposed inside the kneading chamber and rotates around a first rotation axis, and a second rotor that is disposed inside the kneading chamber, is disposed parallel to and adjacent to the first rotor, and rotates around a second rotation axis in a direction opposite to the rotation direction of the first rotor. The first rotor includes a first outer peripheral portion that constitutes the outer periphery of the first rotor in a cross section of the first rotor perpendicular to the direction in which the first rotating shaft extends, and the first outer peripheral portion has a first arc portion and a first non-arc portion that is a portion of the first outer peripheral portion that is different from the first arc portion, and when a virtual circle that passes through the first arc portion and is centered on the first rotating shaft when viewed along the direction in which the first rotating shaft extends is defined as a first virtual circle, the first arc portion has an arc shape centered on the first rotating shaft, is positioned radially outermost of the first rotor, and extends circumferentially of the first rotor continuously for at least one-third of the total circumference of the first virtual circle. The second rotor includes a second outer peripheral portion that constitutes the outer periphery of the second rotor in a cross section of the second rotor perpendicular to the direction in which the second rotation shaft extends, and the second outer peripheral portion has a second arc portion and a second non-arc portion that is a portion of the second outer peripheral portion that is different from the second arc portion, and when a virtual circle that passes through the second arc portion when viewed along the direction in which the second rotation shaft extends and is centered on the second rotation shaft is defined as a second virtual circle, the second arc portion has an arc shape centered on the second rotation shaft, is positioned radially outermost on the second rotor, and extends circumferentially of the second rotor continuously for at least one-third of the total circumference of the second virtual circle, and the first rotor and the second rotor rotate between the first rotation shaft and the second rotation shaft at a predetermined timing so that the first non-arc portion and the second arc portion face each other.

[0007] FIG. 1 is a cross-sectional view of the kneading device 1 as viewed along the axial direction Z. FIG. 2 is a view of the first rotor 50 and the second rotor 60 as viewed along the axial direction Z at a moment when the first rotor 50 and the second rotor 60 shown in FIG. 1 are in opposite phases. FIG. 3 is a view of the first rotor 50 and the second rotor 60 as viewed along the axial direction Z at a moment when the first rotor 50 and the second rotor 60 shown in FIG. 1 are in normal phases. FIG. 4 is a perspective view showing the rotor 40 and the like as shown in FIG. 1. FIG. 5 is a graph showing the torque of the rotor 40 when the phases of the first rotor 50 and the second rotor 60 shown in FIG. 1 are changed. FIG. 6 is a development view of the first rotor 50 shown in FIG. 1. FIG. 7 is a cross-sectional view of a kneading device 201 of a second embodiment as viewed along the axial direction Z.

[0008] First Embodiment A kneading device 1 according to a first embodiment will be described with reference to FIGS. 1 to 6. FIG.

[0009] As shown in FIG. 1 , the kneading apparatus 1 (kneader) is an apparatus that kneads materials using a working fluid in a supercritical state or a subcritical state. Hereinafter, the "supercritical state or subcritical state" may also be referred to as a "supercritical state, etc." The kneading apparatus 1 is, for example, a batch-type kneading apparatus. In the kneading apparatus 1, the working fluid in a supercritical state, etc., swells in the material, melts (plasticizes) the material, and the material is kneaded in a state where the viscosity of the material is reduced.

[0010] The materials kneaded by this kneading device 1 include, for example, a main material and a secondary material. The main material includes, for example, a polymer material, specifically, for example, rubber (such as tire rubber) or resin. The secondary material is an additive (compounding agent) that is added (blended) to the main material. The secondary material may include an inorganic substance or an organic substance. Specifically, for example, if the main material is rubber, the secondary material may include silica, a coupling agent, a vulcanizing agent, etc.

[0011] The working fluid used in this kneading apparatus 1 is a fluid in a supercritical state (supercritical fluid) or a fluid in a subcritical state (subcritical fluid). The kneading apparatus 1 is a supercritical kneading apparatus or a subcritical kneading apparatus. The temperature of the supercritical fluid is equal to or higher than the critical temperature (Tc), and the pressure of the supercritical fluid is equal to or higher than the critical pressure (Pc). The supercritical fluid has the properties of both a liquid and a gas. The supercritical fluid has the ability to melt a solute (solubility) like a liquid and the ability to diffuse a solute (diffusibility) like a gas. The properties of a subcritical fluid (solubility and diffusibility) are almost the same as those of a supercritical fluid. The temperature (T) and pressure (P) of the subcritical fluid satisfy, for example, one of the following conditions. The units of the temperature (T) and critical temperature (Tc) in each of the following examples are Celsius. [Example 1 of Subcritical State] Satisfy T≧Tc and P<Pc. [Example 2 of subcritical state] T<Tc, P<Pc, T is sufficiently higher than room temperature, and P is sufficiently higher than normal pressure (atmospheric pressure). [Example 3 of subcritical state] 0.5<T / Tc<1.0, and 0.5<P / Pc are satisfied. [Example 4 of subcritical state] 0.5<T / Tc, and 0.5<P / Pc<1.0 are satisfied. [Example 5 of subcritical state] When the critical temperature (Tc) is 0°C or lower, 0.5<P / Pc is satisfied.

[0012] The substance constituting the working fluid is preferably a substance that can be brought into a supercritical state or a subcritical state as easily as possible. The difference between the polarity of the working fluid and the polarity of the material is small enough that the material can be dissolved in the working fluid. The substance constituting the working fluid is, for example, carbon dioxide. The critical temperature (Tc) of carbon dioxide is 31°C. The critical pressure (Pc) of carbon dioxide is 7.4 MPa. Carbon dioxide is in a subcritical state, for example, at 31°C or higher and 7.1 MPa or higher. Carbon dioxide is in a subcritical state, for example, at 20°C, if it is 15 MPa or higher. Note that the substance constituting the working fluid does not have to be carbon dioxide, and may be, for example, nitrogen. It is preferable that the working fluid be in a supercritical state rather than a subcritical state. When the working fluid is in a supercritical state, the material is kneaded more than when the working fluid is in a subcritical state.

[0013] The kneading device 1 includes a chamber 10 and a plurality of (a pair of) rotors 40 .

[0014] (Directions Related to the Kneading Apparatus 1) Directions related to the kneading apparatus 1 include the lateral direction X, the vertical direction Y, and the axial direction Z. The axial direction Z is the direction in which the first rotation shaft 50a and the second rotation shaft 60a described below extend. The lateral direction X is a direction perpendicular to the axial direction Z, and is the direction in which a straight line passing through the first rotation shaft 50a and the second rotation shaft 60a extends when viewed along the axial direction Z. The lateral direction X may be a horizontal direction, but does not have to be a horizontal direction unless otherwise specified. In the lateral direction X, the direction from the second rotation shaft 60a toward the first rotation shaft 50a is referred to as a first lateral direction X1, and the direction opposite to the first lateral direction X1 is referred to as a second lateral direction X2. The vertical direction Y is a direction perpendicular to both the axial direction Z and the lateral direction X. The vertical direction Y may be a vertical direction, but does not have to be a vertical direction unless otherwise specified. One side of the vertical direction Y is referred to as a downward direction Y2. As described below, the first rotor 50 and the second rotor 60 rotate in opposite directions. The direction of movement of the first rotor 50 in the second horizontal direction X2 and the second rotor 60 in the first horizontal direction X1 is downward Y2. In the vertical direction Y, the direction opposite to the downward Y2 is upward Y1. The upward Y1 may be an upward direction along the vertical direction, and does not have to be an upward direction along the vertical direction unless otherwise specified. The radial direction of a first imaginary circle 50c centered on the first rotation shaft 50a, which will be described below, is referred to as the first radial direction. The circumferential direction of the first imaginary circle 50c is referred to as the first circumferential direction. The radial direction of a second imaginary circle 60c centered on the second rotation shaft 60a, which will be described below, is referred to as the second radial direction. The circumferential direction of the second imaginary circle 60c is referred to as the second circumferential direction.

[0015] The chamber 10 is a container for kneading materials and includes a kneading chamber 10a.

[0016] The kneading chamber 10a is a section where materials are kneaded. In order to knead the materials, the kneading chamber 10a accommodates the materials together with a working fluid in a supercritical or subcritical state. The kneading chamber 10a is a section where materials are kneaded in the presence (atmosphere) of a working fluid such as a supercritical state. In other words, the kneading chamber 10a is disposed inside the chamber 10. The kneading chamber 10a includes a space (kneading space) where the materials are kneaded and an inner surface of the chamber 10 that forms (surrounds) the kneading space. The kneading chamber 10a is sealed so that the working fluid inside the kneading chamber 10a can maintain a state such as a supercritical state. The kneading chamber 10a includes a rotor accommodating chamber 20 and an upper rotor shaft chamber 30.

[0017] The rotor accommodating chamber 20 is a portion that accommodates the rotor 40. The rotor accommodating chamber 20 includes a space (rotor accommodating space) that accommodates the rotor 40 and the inner surface of the chamber 10 that forms the rotor accommodating space. When two rotors 40 are provided, the rotor accommodating chamber 20 includes a first rotor accommodating chamber 21 and a second rotor accommodating chamber 22.

[0018] The first rotor accommodating chamber 21 accommodates the first rotor 50. The first rotor accommodating chamber 21 has an inner circumferential surface centered on a first rotation shaft 50a (described later). When viewed along the axial direction Z, the inner circumferential surface of the first rotor accommodating chamber 21 has an arc shape centered on the first rotation shaft 50a.

[0019] The second rotor accommodating chamber 22 is a portion that accommodates the second rotor 60. The second rotor accommodating chamber 22 has an inner circumferential surface that is centered on the second rotation shaft 60a (described below). When viewed along the axial direction Z, the inner circumferential surface of the second rotor accommodating chamber 22 is arc-shaped with the second rotation shaft 60a as its center. The space of the first rotor accommodating chamber 21 and the space of the second rotor accommodating chamber 22 (i.e., the rotor accommodating space of the rotor accommodating chamber 20) are generally eyeglass-shaped when viewed along the axial direction Z.

[0020] The inter-rotor-shaft upper chamber 30 increases the amount of material that can be placed in the kneading chamber 10a (e.g., the production volume of the kneading apparatus 1). The inter-rotor-shaft upper chamber 30 extends upward Y1 (here, upward along the vertical direction) from the first rotor accommodating chamber 21 and the second rotor accommodating chamber 22. The inter-rotor-shaft upper chamber 30 is arranged in the inter-rotor-shaft region A. The inter-rotor-shaft region A is the region between the first rotation shaft 50a and the second rotation shaft 60a in the lateral direction X. The inter-rotor-shaft region A is the region further in the lateral second direction X2 than the first rotation shaft 50a and further in the lateral first direction X1 than the second rotation shaft 60a. At least a portion of the inter-rotor-shaft upper chamber 30 is arranged in the inter-rotor-shaft region A. A portion of the inter-rotor-shaft upper chamber 30 may be arranged outward in the lateral direction X than the inter-rotor-shaft region A.

[0021] The shape of the rotor-shaft upper chamber 30 can be set in various ways (arbitrarily). In the example shown in FIG. 1 , the inner surface of the rotor-shaft upper chamber 30 in the first horizontal direction X1 (referred to as the "left side surface") extends upward in the Y1 direction from an upper portion (e.g., an upper end) of the first rotor accommodating chamber 21. The left side surface of the rotor-shaft upper chamber 30 extends upward in the Y1 direction from a position in the first rotor accommodating chamber 21 directly above the first rotating shaft 50a. The left side surface of the rotor-shaft upper chamber 30 is inclined with respect to the up-down direction Y so as to extend more in the horizontal second direction X2 as it progresses upward in the Y1 direction. The left side surface of the rotor-shaft upper chamber 30 may extend in the same direction as the up-down direction Y. The inner surface of the rotor-shaft upper chamber 30 in the second horizontal direction X2 (right side surface) may or may not be symmetrical (e.g., bilaterally symmetrical) with the left side surface of the rotor-shaft upper chamber 30 in the horizontal direction X.

[0022] The rotor 40 kneads the material by rotating relative to the kneading chamber 10a. The rotor 40 is disposed (housed) inside the kneading chamber 10a, and disposed (housed) in the rotor housing chamber 20. A plurality of rotors 40 are provided, for example, two, or three or more may be provided. Of the plurality of rotors 40, two adjacent rotors 40 are referred to as a first rotor 50 and a second rotor 60.

[0023] The first rotor 50 is one of the multiple rotors 40. The first rotor 50 rotates around a first rotation axis 50a. The first rotor 50 is disposed (housed) inside the kneading chamber 10a and disposed (housed) inside the first rotor housing chamber 21. As shown in FIG. 4, the first rotor 50 is provided so as to extend in the direction in which the first rotation axis 50a extends (axial direction Z). Note that in FIG. 4, the chamber 10 is indicated by an imaginary line (two-dot chain line). As shown in FIG. 1, the first rotation axis 50a is the rotation axis of the first rotor 50 relative to the kneading chamber 10a (relative to the chamber 10). When viewed along the axial direction Z, a virtual circle passing through a first arc portion 51 (described later) and centered on the first rotation axis 50a is defined as a first virtual circle 50c. The first virtual circle 50c is a virtual circle perpendicular to the axial direction Z. The first rotor 50 has a first outer circumferential portion 50e. When the first outer peripheral portion 50e includes a first protrusion 53a (described later), the first rotor 50 includes a first base portion 55 (see FIG. 2).

[0024] 2, the first outer peripheral portion 50e is the outer peripheral portion of a cross section of the first rotor 50 seen along the axial direction Z (a cross section perpendicular to the axial direction Z). The first outer peripheral portion 50e is a peripheral portion on the first radially outer side of the cross section of the first rotor 50 seen along the axial direction Z. The first outer peripheral portion 50e includes a first arc portion 51 and a first non-arcuate portion 53.

[0025] The first arc portion 51 has an arc shape centered on the first rotating shaft 50a when viewed along the axial direction Z. The first arc portion 51 is a portion of the first rotor 50 that is located at the outermost part in the first radial direction (maximum outer diameter portion). The first arc portion 51 has a function of applying high stress to the material (described later). The first arc portion 51 is arranged along the first imaginary circle 50c. The first arc portion 51 extends continuously in the first circumferential direction for at least one-third of the entire circumferential length of the first imaginary circle 50c (the length of the first arc portion 51 will be described in detail later).

[0026] The first non-arc portion 53 is a portion of the first outer peripheral portion 50e that is different from the first arc portion 51 (a portion other than the first arc portion 51). The portion of the first outer peripheral portion 50e that is not the first arc portion 51 is the first non-arc portion 53. The first non-arc portion 53 has a function of suppressing heat generation of the material (described below). The first non-arc portion 53 can have various shapes (structures). The first non-arc portion 53 may have only a concave shape (see, for example, the first recess 253b shown in FIG. 7). The first non-arc portion 53 may have an uneven shape as in the example shown in FIG. 2. The first non-arc portion 53 may have a wing shape (see, for example, the first convex portion 53a). For example, the first non-arc portion 53 includes a first convex portion 53a, a first recess 53b, and a first twisted portion 53c (see FIG. 4).

[0027] The first protrusion 53a is a portion (protrusion, wing portion) protruding outward in the first radial direction from the first base 55. Only one first protrusion 53a may be provided, or multiple first protrusions 53a may be provided. In the example shown in FIG. 2, two first protrusions 53a are provided, but three or more first protrusions 53a may be provided. The first rotor 50 is a hybrid rotor having both a substantially cylindrical (substantially roll-shaped) first base 55 and wing-shaped first protrusions 53a. When multiple first protrusions 53a are provided, the configurations of the multiple first protrusions 53a may be identical to each other, substantially identical to each other, or different from each other. In the example shown in FIG. 2, the configurations of the two first protrusions 53a are symmetrical to each other in the first circumferential direction. The width of the first protrusions 53a in the first circumferential direction may be narrower toward the outside in the first radial direction (may be tapered), or may be constant.

[0028] The first recess 53b is a portion for better distribution of the material (reducing uneven distribution of the material and uneven mixing). The first recess 53b is a portion for taking in the material from the upper rotor gap Ay1 (see FIG. 1) and moving the material to the lower rotor gap Ay2 (see FIG. 1). The first recess 53b has a shape recessed toward the first radially inward direction (inward in the radial direction of the first rotor 50). The first recess 53b is disposed further toward the first radially inward direction than the first imaginary circle 50c. The "recessed shape" of the first recess 53b is, for example, a groove shape (see FIG. 4). When viewed along the axial direction Z, the first recess 53b may include a straight line or a curved line, and may include, for example, an arc shape (a circular arc shape or a non-circular arc shape). For example, the first recess 53b includes a first inter-convex recess 53b1 and a first inter-convex outer recess 53b2.

[0029] The first inter-convex portion recess 53b1 is formed by two first convex portions 53a adjacent to each other in the first circumferential direction. Here, when the first rotor 50 has two first convex portions 53a, the region between the two first convex portions 53a includes a region with a shorter distance in the first circumferential direction and a region with a longer distance in the first circumferential direction. In this case, the first inter-convex portion recess 53b1 is formed (disposed) in the region between the two first convex portions 53a with a shorter distance in the first circumferential direction.

[0030] The first inter-convex portion outer recess 53b2 is disposed on the "first inter-convex portion outer side" of the first convex portion 53a. The "first inter-convex portion outer side" is the opposite side of the first convex portion 53a from the first inter-convex portion recess 53b1 (opposite side in the first circumferential direction) with respect to the first convex portion 53a. The first inter-convex portion outer recess 53b2 is formed by the first convex portion 53a. In the example shown in FIG. 2 , the first inter-convex portion outer recess 53b2 is disposed in the region between the first convex portion 53a and the first arc portion 51. The first inter-convex portion outer recess 53b2 is provided on the first inter-convex portion outer side of each of the two first convex portions 53a (two in total).

[0031] The first twisted portion 53c (see FIG. 4) is a portion for distributing the material in the axial direction Z. The first twisted portion 53c is a portion for inducing a flow of the material in the axial direction Z and promoting distribution of the material in the axial direction Z. As shown in FIG. 4, when the first rotor 50 is viewed radially, the first twisted portion 53c has a shape twisted about the first rotation shaft 50a so as to extend in a direction inclined relative to the first rotation shaft 50a. The first twisted portion 53c has a shape twisted in a "predetermined twisted direction" about the first rotation shaft 50a. That is, the cross-sectional shape of the first twisted portion 53c viewed along the axial direction Z is a shape that rotates in the "predetermined twisted direction" as the position in the axial direction Z changes. The "predetermined twisted direction" is a clockwise or counterclockwise direction when viewed from one side in the axial direction Z. Specifically, the first convex portion 53a and the first concave portion 53b are spiral-shaped with the first rotation shaft 50a as the central axis. The first twisted portion 53c is provided over the entirety (or substantially the entirety) of the first rotor 50 in the axial direction Z. Note that the first twisted portion 53c may be provided over only a portion of the first rotor 50 in the axial direction Z.

[0032] 2, the first base portion 55 is a portion of the first rotor 50 other than the first protruding portion 53a. The first base portion 55 includes, for example, the first rotating shaft 50a.

[0033] As shown in Fig. 1, the second rotor 60 is one (the other) of the multiple rotors 40 and is provided separately from the first rotor 50. The second rotor 60 rotates around a second rotation axis 60a. The second rotation axis 60a is the rotation axis of the second rotor 60 relative to the kneading chamber 10a (relative to the chamber 10). When viewed along the axial direction Z, a virtual circle that passes through a second arc portion 61 (described later) and has its center at the second rotation axis 60a is defined as a second virtual circle 60c. The second virtual circle 60c is a virtual circle that is perpendicular to the axial direction Z.

[0034] The second rotor 60 rotates in the opposite direction to the rotation direction of the first rotor 50. Specifically, for example, when viewed from one side in the axial direction Z, if the first rotor 50 rotates clockwise, the second rotor 60 rotates counterclockwise. The magnitude of the rotation speed (number of rotations) of the second rotor 60 is equal to or approximately equal to the magnitude of the rotation speed of the first rotor 50. Note that the magnitude of the rotation speed of the second rotor 60 may be different from the magnitude of the rotation speed of the first rotor 50.

[0035] The second rotor 60 is disposed (housed) inside the kneading chamber 10a, and is disposed (housed) inside the second rotor housing chamber 22. As shown in Fig. 4, the second rotor 60 is disposed parallel to the first rotor 50. Specifically, the extending direction of the first rotation shaft 50a and the extending direction of the second rotation shaft 60a are parallel to each other. As shown in Fig. 1, the second rotor 60 is disposed adjacent to the first rotor 50. The second rotor 60 is disposed so that a small gap is formed in the lateral direction X between the first imaginary circle 50c and the second imaginary circle 60c.

[0036] The configuration (structure, shape, etc.) of the second rotor 60 is, for example, the same as the configuration of the first rotor 50. However, the configuration of the second rotor 60 may be different from the configuration of the first rotor 50. The configuration of the second rotor 60 may be substantially the same as the configuration of the first rotor 50, or may be completely different from the configuration of the first rotor 50. Below, a case where the configurations of the first rotor 50 and the second rotor 60 are the same will be described. As shown in FIG. 2 , the second rotor 60 has a second outer circumferential portion 60e. When the second outer circumferential portion 60e has a second convex portion 63a, the second rotor 60 has a second base portion 65.

[0037] The second outer periphery 60e (corresponding to the first outer periphery 50e of the first rotor 50) is the outer periphery of the cross section of the second rotor 60 as viewed along the axial direction Z. The second outer periphery 60e includes a second arc portion 61 and a second non-arc portion 63.

[0038] The second arc-shaped portion 61 (corresponding to the first arc-shaped portion 51) has an arc-shaped shape centered on the second rotating shaft 60a when viewed from the axial direction Z. The second arc-shaped portion 61 is the portion of the second rotor 60 that is located at the outermost part in the second radial direction (the portion with the largest outer diameter). The second arc-shaped portion 61 is arranged along the second imaginary circle 60c. The second arc-shaped portion 61 extends continuously in the second circumferential direction for at least one-third of the entire circumference of the second imaginary circle 60c (details will be described later). As shown in FIG. 1 , when each rotor rotates, there is a timing when the first non-arc-shaped portion 53 and the second arc-shaped portion 61 face each other between the first rotating shaft 50a and the second rotating shaft 60a (rotor shaft region A) (details will be described later).

[0039] As shown in FIG. 2 , the second non-arc portion 63 (corresponding to the first non-arc portion 53) is a portion of the second outer peripheral portion 60e that is different from the second arc portion 61 (a portion other than the second arc portion 61). For example, the second non-arc portion 63 includes a second convex portion 63a, a second concave portion 63b, and a second twist portion 63c (see FIG. 4) (corresponding to the first twist portion 53c). The second convex portion 63a (corresponding to the first convex portion 53a) is a portion (protrusion, wing portion) that protrudes outward in the second radial direction from the second base portion 65. The second concave portion 63b (corresponding to the first concave portion 53b) has a shape that is concave inward in the second radial direction and is disposed more inward in the second radial direction than the second imaginary circle 60c.

[0040] As shown in Fig. 4, the second twisted portion 63c has a shape twisted in a "predetermined twisted direction" around the second rotation shaft 60a. This "predetermined twisted direction" is the same direction as the twisted direction ("predetermined twisted direction") of the first twisted portion 53c. The second twisted portion 63c is provided over the entire (or substantially the entire) axial direction Z of the second rotor 60. Note that the second twisted portion 63c may be provided over only a portion of the second twisted portion 63c in the axial direction Z.

[0041] (Function of Twisted Portion) The first twisted portion 53c and the second twisted portion 63c distribute the material in the axial direction Z. Specifically, as described above, the first rotor 50 and the second rotor 60 rotate in opposite directions. Furthermore, the first twisted portion 53c and the second twisted portion 63c have the same twist direction. Therefore, the direction of material movement in the axial direction Z associated with the rotation of the first rotor 50 is opposite to the direction of material movement in the axial direction Z associated with the rotation of the second rotor 60. Therefore, the first twisted portion 53c and the second twisted portion 63c make it easier for the material to be distributed in the axial direction Z (improving the distribution performance in the axial direction Z of the kneading device 1).

[0042] Note that if the twist directions of the first twist portion 53c and the second twist portion 63c are opposite, the direction of material movement in the axial direction Z associated with the rotation of the first rotor 50 and the direction of material movement in the axial direction Z associated with the rotation of the second rotor 60 will be the same. As a result, the material may be biased to one side in the axial direction Z, resulting in insufficient distribution in the axial direction Z. Here, a seal for sealing the kneading chamber 10a is usually provided at the end of the rotor 40 in the axial direction Z within the kneading chamber 10a. If the material is biased to one side in the axial direction Z, the material may press against this seal with a large force, potentially affecting the seal. Therefore, it is preferable that the twist directions of the first twist portion 53c and the second twist portion 63c are the same (predetermined twist direction).

[0043] The second base portion 65 (see FIG. 2) (corresponding to the first base portion 55) is the portion of the second rotor 60 other than the second protrusion portion 63a.

[0044] (Operation) The kneading device 1 shown in FIG. 1 is configured to operate as follows. The material and working fluid are placed in a sealed kneading chamber 10a. In this state, the rotor 40 rotates relative to the kneading chamber 10a. The material moves from the upper rotor gap Ay1 to the lower rotor gap Ay2, passes through the gap between the inner surface of the rotor housing chamber 20 and the rotor 40, and returns to the upper rotor gap Ay1. As the rotor 40 continues to rotate, the material repeats this movement. As a result, the material is distributed (distributed and mixed, and distribution progresses), reducing uneven distribution of the material (uneven mixing). Specifically, uneven distribution of the secondary material in the main material is reduced. Furthermore, the material is dispersed and finely scattered. Specifically, the secondary material of the material is finely scattered in the main material.

[0045] (Effects of using a working fluid in a supercritical state or the like) Here, an internal mixer that does not use a working fluid in a supercritical state or the like is referred to as a "conventional internal mixer." When a working fluid in a supercritical state or the like is used, materials can be mixed at low temperatures compared to conventional internal mixers, and heat generation from the materials can be suppressed. Furthermore, when a working fluid in a supercritical state or the like is used, the viscosity of the materials is reduced and the fluidity of the materials is improved compared to conventional internal mixers, resulting in better distribution of the materials. Furthermore, because the viscosity of the materials is reduced and the fluidity of the materials is improved, the power required to mix the materials in the mixer 1 is reduced.

[0046] (Function of the arc section) When a working fluid such as a supercritical fluid is used, the fluidity of the material is improved compared to conventional internal mixers, but the stress applied to the material is reduced. Therefore, with materials that require physical force to disperse (such as highly cohesive fillers), dispersion may be hindered (dispersibility may decrease).

[0047] Therefore, the first rotor 50 includes a first arc portion 51, and the second rotor 60 includes a second arc portion 61. The first arc portion 51 and the second arc portion 61 can impart high stress to the material. Specifically, the material in the upper rotor gap Ay1 passes through the gap between the first rotor 50 and the second rotor 60. As shown in FIG. 3 , when the first arc portion 51 and the second arc portion 61 face each other, the gap between the first arc portion 51 and the second arc portion 61 is referred to as the arc portion gap A1. When the material passes through the arc portion gap A1, an elongational flow occurs in the material in the vertical direction Y, and an elongational stress is imparted to the material (high stress acts on the material). As a result, the dispersibility of the material is improved.

[0048] (Function of Non-Circular Arc Portion) When a material is kneaded using the first circular arc portion 51 and the second circular arc portion 61, high stress can be applied to the material, but heat generation from the material during kneading can become a problem. For example, if heat generation from the material causes excessive (or insufficient) chemical reaction in the material, heat generation from the material can become a problem. Specifically, for example, there is a process (kneading process B) in which a crosslinking agent (secondary material) such as sulfur or a vulcanization accelerator is kneaded into a rubber material (main material). In this kneading process B, if the material generates too much heat during kneading, scorching (excessive vulcanization) occurs in the material, in which crosslinking progresses during kneading, and the material properties may be reduced.

[0049] To suppress the heat generation of this material, rearranging the rotors 40 requires time and effort and costs. Specifically, rearranging the rotors 40 between a rotor that generates a lot of heat when kneading a material that requires physical force to disperse and a rotor that generates little heat when kneading a material for which heat generation is a problem requires time and effort and costs.

[0050] (Opposite of the First Non-Circular Arc Portion 53 and the Second Circular Arc Portion 61) Therefore, the kneading device 1 is configured to apply high stress to the material and suppress heat generation of the material (enabling kneading at low temperatures). Specifically, in the kneading device 1, as shown in FIG. 1 , there is a timing when the first non-circular arc portion 53 and the second arc portion 61 face each other (more specifically, face each other in the lateral direction X) between the first rotating shaft 50a and the second rotating shaft 60a (inter-rotor shaft region A). Hereinafter, when an element of the first rotor 50 (here, the first non-circular arc portion 53) and an element of the second rotor 60 (here, the second arc portion 61) "face each other," this means that they face each other in the lateral direction X in the inter-rotor shaft region A. When the first non-circular arc portion 53 and the second arc portion 61 face each other, the range of the second arc portion 61 in the vertical direction Y (vertical range) is included in at least a part of the vertical range of the first non-circular arc portion 53.

[0051] Furthermore, in the kneading device 1, there is a timing (not shown) when the first arc-shaped portion 51 and the second non-arcuate portion 63 face each other in the inter-rotor axis region A. When the first arc-shaped portion 51 and the second non-arcuate portion 63 face each other, the range (vertical range) of the first arc-shaped portion 51 in the vertical direction Y is included in at least a part of the vertical range of the second non-arcuate portion 63. Hereinafter, unless otherwise specified, a description of the first rotor 50 may be read as a description of the second rotor 60, and a description of the second rotor 60 may be read as a description of the first rotor 50.

[0052] When the first non-arc portion 53 and the second arc portion 61 face each other, the material passes through the arc portion-non-arc portion gap A3. The arc portion-non-arc portion gap A3 is the gap between the first non-arc portion 53 and the second arc portion 61 when the first non-arc portion 53 and the second arc portion 61 face each other. This arc portion-non-arc portion gap A3 is larger than the arc portion gap A1 (see FIG. 3 ). Therefore, the amount of heat generated by the material passing through the arc portion-non-arc portion gap A3 is smaller than the amount of heat generated by the material passing through the arc portion gap A1.

[0053] The circumferential lengths of the arc-shaped and non-arcuate portions can be adjusted as needed. As an example, in the configuration shown in FIG. 2 , the following states occur in sequence. In the state shown in FIG. 2 , the rotational center of the first non-arcuate portion 53 faces the rotational center of the second arc-shaped portion 61. When each rotor rotates 90 degrees from this state, the upstream end of the first non-arcuate portion 53 faces the rotational center of the second arc-shaped portion 61. In other words, the downstream end of the first arc-shaped portion 51 faces the rotational center of the second non-arcuate portion 63. When each rotor rotates 90 degrees further, the rotational center of the first arc-shaped portion 51 faces the rotational center of the second non-arcuate portion 63. When each rotor rotates 90 degrees further, the rotational center of the first arc-shaped portion 51 faces the rotational center of the second non-arcuate portion 63. In other words, the downstream end of the first non-arcuate portion 53 in the rotational direction faces the downstream end of the second arcuate portion 61. When each rotor rotates by another 90 degrees, the rotors return to the state shown in FIG.

[0054] Note that there may be times when the first non-arcuate portion 53 and the second arcuate portion 61 do not face each other. For example, the first non-arcuate portion 53 and the second arcuate portion 61 may face each other at certain times and not face each other at other times. The first non-arcuate portion 53 and the second arcuate portion 61 may face each other periodically. For example, there may be times when the first non-arcuate portion 53 and the second arcuate portion 61 face each other while at least one of the first rotor 50 and the second rotor 60 makes one rotation.

[0055] Furthermore, the first non-arcuate portion 53 and the second arcuate portion 61 do not necessarily have to face each other at another position in the axial direction Z at the same time that they face each other at a certain position in the axial direction Z.

[0056] (Relationship between the effect of applying high stress and the effect of suppressing heat generation) The time during which the first arc-shaped portion 51 and the second arc-shaped portion 61 face each other as shown in Fig. 3 is compared with the time during which the first non-arcuate portion 53 and the second arc-shaped portion 61 face each other as shown in Fig. 2. The longer the time during which the first non-arcuate portion 53 and the second arc-shaped portion 61 face each other, the greater the effect of suppressing the heat generation of the material (heat generation suppression effect). On the other hand, as shown in Fig. 3, the longer the time during which the first arc-shaped portion 51 and the second arc-shaped portion 61 face each other, the greater the effect of applying high stress to the material (high stress application effect).

[0057] As shown in Fig. 4, there is a case where the first rotor 50 has a first twisted portion 53c and the second rotor 60 has a second twisted portion 63c. In this case, as shown in Fig. 2, the more the area where the first non-arcuate portion 53 and the second arcuate portion 61 face each other in the axial direction Z, the more the heat generation suppression effect is obtained. Also, as shown in Fig. 3, the more the area where the first arcuate portion 51 and the second arcuate portion 61 face each other in the axial direction Z, the more the high stress application effect is obtained.

[0058] (Difference in Effects Due to Phase) The balance between the effect of applying high stress and the effect of suppressing heat generation (low-temperature kneading) changes depending on the difference in phase between the first rotor 50 and the second rotor 60. For example, as shown in FIG. 3 , a phase in which the first arc-shaped portion 51 and the second arc-shaped portion 61 face each other directly, and the first non-arcuate portion 53 and the second non-arcuate portion 63 face each other directly (not shown) is defined as a "positive phase." Furthermore, as shown in FIG. 2 , a phase in which the first non-arcuate portion 53 and the second arc-shaped portion 61 face each other directly, and the first arc-shaped portion 51 and the second non-arcuate portion 63 face each other directly (not shown) is defined as a "negative phase." When the positive phase and the negative phase are defined in this way, the closer the first rotor 50 and the second rotor 60 are to the positive phase (see FIG. 3 ), the greater the effect of applying high stress, and the closer they are to the negative phase (see FIG. 2 ), the greater the effect of suppressing heat generation.

[0059] (Adjusting the Effect by Adjusting the Phase) When kneading materials or processes that require high stress, it is preferable that the first rotor 50 and the second rotor 60 be in positive phase or a phase close to the positive phase, as shown in Fig. 3. When kneading materials or processes that do not require high stress, it is preferable that the first rotor 50 and the second rotor 60 be in opposite phase or a phase close to the opposite phase, as shown in Fig. 2. By adjusting the phase in this way, it is possible to achieve both the effect of applying high stress in the positive phase (see Fig. 3) and the effect of suppressing heat generation in the opposite phase (see Fig. 2) without rearranging the rotor 40.

[0060] (Specific example of differences in effect depending on phase) FIG. 5 shows the average torque and maximum torque of the rotor 40 during kneading when the first rotor 50 and the second rotor 60 are in positive phase (see FIG. 3) and when they are in negative phase (see FIG. 2). In this specific example, the first rotor 50 and the second rotor 60 have the same rotation speed and opposite rotation directions. In this specific example, as shown in FIG. 2, the cross-sectional shape of the first rotor 50 and the cross-sectional shape of the second rotor 60 are the same when viewed along the axial direction Z. In this specific example, the length of the first arc-shaped portion 51 in the first circumferential direction is ½ of the circumference of the first virtual circle 50c, and the length of the first non-arcuate portion 53 in the first circumferential direction is ½ of the circumference of the first virtual circle 50c.

[0061] The results shown in FIG. 5 indicate that when the first rotor 50 and the second rotor 60 are in opposite phase (see FIG. 2), the average torque is reduced by approximately 6% and the maximum torque is reduced by approximately 40% compared to when the rotor is in forward phase (see FIG. 3). Here, a small torque of the rotor 40 (see FIG. 2) indicates a small amount of heat generated from the material. Therefore, in the opposite phase (see FIG. 2), the facing of the arc portion and the non-arc portion (the first arc portion 51 and the second non-arc portion 63, and the second arc portion 61 and the first non-arc portion 53) suppresses heat generation from the material during kneading. Furthermore, a large torque of the rotor 40 (see FIG. 3) indicates a high stress applied to the material. Therefore, in the forward phase (see FIG. 3), the facing of the arc portions (the first arc portion 51 and the second arc portion 61) can apply a high stress to the material during kneading.

[0062] (Differences in Effects Due to the Shape of the Rotor 40) The balance between the effect of applying high stress and the effect of suppressing heat generation (low-temperature kneading) changes depending on the length of the first arc-shaped portion 51 in the first circumferential direction relative to the length of the entire circumference of the first virtual circle 50c shown in Fig. 2. Furthermore, the balance between the effect of applying high stress and the effect of suppressing heat generation (low-temperature kneading) changes depending on the length of the second arc-shaped portion 61 in the first circumferential direction relative to the length of the entire circumference of the second virtual circle 60c. Here, the description will mainly focus on the first rotor 50.

[0063] As described above, the longer the time that the first non-circular arc portion 53 and the second arc portion 61 face each other relative to the time that the first arc portion 51 and the second arc portion 61 face each other, the greater the heat generation suppression effect. Therefore, by reducing the number of first arc portions 51, which generate a lot of heat, and increasing the number of first non-circular arc portions 53 in the first outer peripheral portion 50e, the time that the first non-circular arc portion 53 and the second arc portion 61 face each other is increased, thereby enhancing the heat generation suppression effect. However, if the number of first arc portions 51, which generate a lot of heat, is reduced too much, the effect of applying high stress is limited. Furthermore, if the number of first arc portions 51, which generate a lot of heat, is increased too much, heat generation during kneading becomes a problem. Therefore, by appropriately adjusting (setting) the length of the first arc portions 51 in the first circumferential direction relative to the total circumferential length of the first virtual circle 50c in the first rotor 50, it is possible to achieve both the effect of applying high stress and the effect of suppressing heat generation.

[0064] (Conditions for the Length of the Circular Arc Portion) [Condition α1] The first arc portion 51 extends continuously in the first circumferential direction (the circumferential direction of the first rotor 50) for at least one-third or more of the length of the entire circumference of the first imaginary circle 50c. In this case, the effect of applying high stress by the first arc portion 51 can be ensured. Note that even if a portion of the first outer peripheral portion 50e extends along the first imaginary circle 50c, a portion whose length in the first circumferential direction is not continuous for one-third or more of the length of the entire circumference of the first imaginary circle 50c is not included in the first arc portion 51. For example, in the example shown in FIG. 2 , the tip of the first convex portion 53a is a portion that extends along the first imaginary circle 50c. However, the length in the first circumferential direction of the tip of the first convex portion 53a is not continuous for one-third or more of the length of the entire circumference of the first imaginary circle 50c. Therefore, the tip of the first convex portion 53a is not included in the first arc portion 51.

[0065] The first rotor 50 is provided to extend in the axial direction Z (see FIG. 4 ), and the above-mentioned [Condition α1] is satisfied at least in part of the axial direction Z positions (positions in the axial direction Z) of the first rotor 50. The above-mentioned [Condition α1] may be satisfied in part of the axial direction Z of the first rotor 50. It is preferable that the above-mentioned [Condition α1] is satisfied over the entire axial direction Z of the first rotor 50.

[0066] The second arc-shaped portion 61 of the second rotor 60 satisfies the same condition as the above-mentioned [Condition α1]. That is, the second arc-shaped portion 61 extends continuously in the first circumferential direction for at least one-third or more of the entire circumferential length of the second imaginary circle 60c.

[0067] [Condition α2] The length of the first arc-shaped portion 51 that extends continuously in the first circumferential direction is preferably ¾ or less of the total circumferential length of the first imaginary circle 50c. In this case, the length of the first non-arcuate portion 53 in the first circumferential direction is longer than ¼ of the total circumferential length of the first imaginary circle 50c. This ensures the effect of suppressing heat generation by the first non-arcuate portion 53. Note that the "length of the first non-arcuate portion 53 in the first circumferential direction" refers to the length of the projected first non-arcuate portion 53 in the first circumferential direction when the first non-arcuate portion 53 is projected radially outward onto the first imaginary circle 50c.

[0068] Since the first rotor 50 is provided so as to extend in the axial direction Z (see FIG. 4), it is preferable that the above-mentioned [Condition α2] be satisfied at least at a portion of the first rotor 50 in the axial direction Z.

[0069] It is preferable that the second arc-shaped portion 61 of the second rotor 60 satisfy the same condition as the above-mentioned [Condition α2]. That is, the length of the second arc-shaped portion 61 that extends continuously in the second circumferential direction is preferably ¾ or less of the entire circumferential length of the second virtual circle 60c. When the first arc-shaped portion 51 satisfies the above-mentioned [Condition α2], it is preferable that the second arc-shaped portion 61 satisfy the same condition as the above-mentioned [Condition α2]. When the first arc-shaped portion 51 satisfies the above-mentioned [Condition α2], the second arc-shaped portion 61 does not have to satisfy the same condition as the above-mentioned [Condition α2].

[0070] (Twist Angle Conditions) FIG. 6 shows a development of the first rotor 50 (of the first outer peripheral portion 50e). This development of the first rotor 50 is a development of an imaginary cylinder (not shown) around the first rotor 50 shown in FIG. 2, in which the first outer peripheral portion 50e is projected onto the imaginary cylinder. Specifically, an imaginary cylinder is defined as a cylinder whose center is the first rotation axis 50a and whose cross section viewed from the axial direction Z overlaps with the first imaginary circle 50c. The first outer peripheral portion 50e is projected outward in the first radial direction onto this imaginary cylinder. The imaginary cylinder onto which the first outer peripheral portion 50e is projected is opened by a straight line on the outer peripheral surface of this imaginary cylinder that extends in the axial direction Z, resulting in a planar view. The view shown in this planar view is the development of the first rotor 50 shown in FIG. 6.

[0071] The length of the first rotor 50 in the axial direction Z (the direction in which the first rotating shaft 50a (see FIG. 4) extends) is defined as a first axial length L. The radius of the first imaginary circle 50c (see FIG. 2) is defined as a first radius R. The angle formed by the axial direction Z and the direction in which the first non-arc portion 53 extends (more specifically, the direction in which the center line C53 of the first non-arc portion 53 extends) is defined as a first twist angle θ. The center line C53 is a line connecting the center positions of the first non-arc portion 53 in the first circumferential direction (in the example shown in FIG. 2, the center positions of the first inter-convex portion concave portions 53b1 in the first circumferential direction).

[0072] As the first twist angle θ increases, the region in the first circumferential direction where only the first arc portion 51 exists (arc portion region E1) becomes smaller, and the region in the first circumferential direction where the first non-arc portion 53 exists (non-arc portion region E3) becomes larger. Therefore, the heat generation suppression effect becomes greater. On the other hand, as the first twist angle θ decreases, the non-arc portion region E3 becomes smaller and the arc portion region E1 becomes larger, and the effect of applying high stress becomes greater.

[0073] Specifically, the first twist angle θ preferably satisfies the following formula (1): Furthermore, the first twist angle θ preferably satisfies formula (2): The first twist angle θ more preferably satisfies formula (3): Formula (3) satisfies the conditions of both formulas (1) and (2).

[0074] Tan －１ (πR / 4L)≦θ...(1) θ≦tan －1 (πR / 2L)...(2) tan－1 (πR / 4L)≦θ≦tan －1 (πR / 2L)...(3)

[0075] When the first helix angle θ satisfies formula (1), a non-arcuate region E3 is secured. When formula (1) is satisfied, the length (L tan θ) of the center line C53 of the first non-arcuate portion 53 in the first circumferential direction in the developed view of the first rotor 50 is equal to or greater than πR / 4. In this case, a heat generation suppression effect is obtained compared to when the first helix angle θ does not satisfy formula (1).

[0076] When the first helix angle θ satisfies formula (2), the arc region E1 is secured. When formula (2) is satisfied, the length (L tan θ) of the center line C53 of the first non-arcuate portion 53 in the first circumferential direction in the developed view of the first rotor 50 is equal to or less than πR / 2. In this case, a high stress application effect can be obtained compared to when the first helix angle θ does not satisfy formula (2).

[0077] When formula (3) is satisfied for the first helix angle θ, an arc region E1 and a non-arcuate region E3 are ensured. When formula (3) is satisfied, in a developed view of the first rotor 50, the length (L tan θ) in the first circumferential direction of the center line C53 of the first non-arcuate portion 53 is equal to or greater than πR / 4 and equal to or less than πR / 2. In this case, it is possible to achieve both the effect of suppressing heat generation and the effect of applying high stress.

[0078] When the first rotor 50 (with respect to the first helix angle θ) satisfies formula (1), formula (2), or formula (3), it is preferable that the second rotor 60 (see FIG. 2) also satisfies the same condition as formula (1), formula (2), or formula (3) above. When the first rotor 50 (with respect to the first helix angle θ) satisfies formula (1), formula (2), or formula (3), the second rotor 60 does not have to satisfy formula (1), formula (2), or formula (3) above.

[0079] The effects of the kneading device 1 shown in FIG. 1 are as follows. The kneading device 1 includes a kneading chamber 10a, a first rotor 50, and a second rotor 60. The kneading chamber 10a is a section where materials are kneaded in the presence of a working fluid in a supercritical or subcritical state. The first rotor 50 is disposed inside the kneading chamber 10a and rotates around a first rotation shaft 50a. The second rotor 60 is disposed inside the kneading chamber 10a, is disposed parallel to the first rotor 50, is disposed adjacent to the first rotor 50, and rotates around the second rotation shaft 60a in the direction opposite to the rotation direction of the first rotor 50.

[0080] [Configuration 1-1] The first rotor 50 has a first outer circumferential portion 50e. The first outer circumferential portion 50e is the outer circumferential portion of the cross section of the first rotor 50 as viewed from the direction in which the first rotating shaft 50a extends (axial direction Z). The first outer circumferential portion 50e has a first arc-shaped portion 51 and a first non-arc-shaped portion 53. The first non-arc-shaped portion 53 is a portion of the first outer circumferential portion 50e that is different from the first arc-shaped portion 51. When viewed along the direction in which the first rotating shaft 50a extends (axial direction Z), a virtual circle that passes through the first arc-shaped portion 51 and has its center at the first rotating shaft 50a is defined as a first virtual circle 50c.

[0081] [Configuration 1-2] The first arc portion 51 has an arc shape centered on the first rotating shaft 50a, and is disposed at the radially outermost portion of the first rotor 50.

[0082] [Configuration 1-3] The first arc portion 51 extends continuously in the circumferential direction (first circumferential direction) of the first rotor 50 over at least one-third of the total circumferential length of the first imaginary circle 50c.

[0083] [Configuration 1-4] The second rotor 60 includes a second outer periphery 60e. The second outer periphery 60e is the outer periphery of the cross section of the second rotor 60 as viewed from the direction in which the second rotation shaft 60a extends (axial direction Z). The second outer periphery 60e includes a second arc-shaped portion 61 and a second non-arc-shaped portion 63. The second non-arc-shaped portion 63 is a portion of the second outer periphery 60e that is different from the second arc-shaped portion 61. When viewed from the direction in which the second rotation shaft 60a extends (axial direction Z), a virtual circle that passes through the second arc-shaped portion 61 and has its center at the second rotation shaft 60a is defined as a second virtual circle 60c.

[0084] [Configuration 1-5] The second arc portion 61 is arc-shaped with its center at the second rotary shaft 60a, and is disposed at the radially outermost portion of the second rotor 60.

[0085] [Configuration 1-6] The second arc portion 61 extends continuously in the circumferential direction of the second rotor 60 (second circumferential direction) for at least one-third of the length of the entire circumference of the second imaginary circle 60c.

[0086] [Configuration 1-7] Between the first rotating shaft 50a and the second rotating shaft 60a (rotor shaft area A), there is a timing when the first non-circular portion 53 and the second circular portion 61 face each other.

[0087] With the above [Configuration 1-2] and [Configuration 1-5], when the first arc portion 51 and the second arc portion 61 face each other, the gap (arc portion gap A1) between the first arc portion 51 and the second arc portion 61 tends to become narrow, as shown in FIG. 3 . Furthermore, with the above [Configuration 1-3] and [Configuration 1-6], the lengths of the first arc portion 51 and the second arc portion 61 are ensured. Therefore, when the first arc portion 51 and the second arc portion 61 face each other, high stress can be applied to the material as it passes through the arc portion gap A1. Therefore, the first rotor 50 and the second rotor 60 can apply high stress to the material.

[0088] The above-mentioned [Configuration 1-7] provides the following effect. As shown in Fig. 1, when the second arc portion 61 and the first non-arc portion 53 face each other, the gap between the second arc portion 61 and the first non-arc portion 53 (arc portion-non-arc portion gap A3) is wider than the arc portion gap A1 (see Fig. 3). Therefore, heat generation from the material passing through the arc portion-non-arc portion gap A3 can be suppressed.

[0089] Therefore, the kneading device 1 can suppress heat generation from the material in the rotors 40 (the first rotor 50 and the second rotor 60) that can apply high stress to the material.

[0090] As shown in Fig. 4, the first non-arcuate portion 53 has a shape (first twist portion 53c) twisted around the first rotation shaft 50a so as to extend in a direction inclined relative to the first rotation shaft 50a. As shown in Fig. 6, the length of the first rotor 50 in the direction in which the first rotation shaft 50a extends (axial direction Z) is defined as a first axial length L. The radius of the first imaginary circle 50c (see Fig. 1) is defined as a first radius R. The angle between the direction in which the first rotation shaft 50a extends (axial direction Z) and the direction in which the first non-arcuate portion 53 extends is defined as a first twist angle θ. In this case, the following formula is satisfied.

[0091] [Configuration 2] tan －1 (πR / 4L)≦θ≦tan －1 (πR / 2L)

[0092] The above-described [Configuration 2] makes it possible to ensure, in the first outer peripheral portion 50e, a region in the first circumferential direction where only the first arc-shaped portion 51 exists (arc-shaped portion region E1), and a region in the first circumferential direction where the first non-arc-shaped portion 53 exists (non-arc-shaped portion region E3). Therefore, it is possible to obtain a good balance between the effect of applying high stress to the material and the effect of suppressing heat generation from the material.

[0093] [Configuration 3] As shown in Figure 1, the length of the first arc portion 51 that extends continuously in the circumferential direction (first circumferential direction) of the first rotor 50 is 3 / 4 or less of the length of the entire circumference of the first virtual circle 50c.

[0094] The above [Configuration 3] provides the following effect. In the above [Configuration 1-3], the first arc portion 51 extends continuously in the first circumferential direction for at least one-third of the total circumferential length of the first imaginary circle 50c. If the first arc portion 51 is too long, the first non-arc portion 53 becomes too small, limiting the effect of suppressing heat generation in the material. Therefore, in the above [Configuration 3], the length of the first arc portion 51 that extends continuously in the first circumferential direction is no more than three-quarters of the total circumferential length of the first imaginary circle 50c. This ensures the size of the first non-arc portion 53. This ensures the effect of suppressing heat generation in the material.

[0095] Second Embodiment A kneading device 201 of a second embodiment will be described with reference to Fig. 7, with respect to differences from the first embodiment. Note that, among the kneading device 201 of the second embodiment, a description of commonalities with the first embodiment will be omitted.

[0096] In the example shown in Fig. 2, the first non-arcuate portion 53 includes a first convex portion 53a and a first concave portion 53b. On the other hand, as shown in Fig. 7, the first non-arcuate portion 253 may include a first concave portion 253b and not include the first convex portion 53a (see Fig. 2). As with the first rotor 50, the second rotor 60 may also include a second non-arcuate portion 263 including a second concave portion 263b and not include the second convex portion 63a (see Fig. 2).

[0097] The first recess 253b may have any shape (the same applies to the second recess 263b). In the example shown in Fig. 9, the first recess 253b has an arc shape recessed inward in the first radial direction, and is an arc shape or a substantially arc shape.

[0098] (Modifications) The above embodiments may be modified in various ways. For example, components (including modifications) of different embodiments may be combined with each other. For example, modifications of the above embodiments may be combined with each other in various ways. For example, the number of components (including modifications) of the above embodiments may be changed, or some of the components may not be provided. For example, the arrangement of the components may be changed. For example, the inclusion relationships of the components may be changed in various ways. For example, a component described as a lower-level component included in a higher-level component may not be included in this higher-level component, but may be included in another component. For example, what is described as multiple different components or parts may be combined into a single component or part. For example, what is described as a single component or part may be provided as multiple different components or parts. For example, each component may have only a portion of its respective feature (function, arrangement, shape, operation, etc.).

[0099] 2 may include only one first protrusion 53 a. Alternatively, the first rotor 50 may include two first non-arcuate portions 53 (at two locations).

[0100] In another embodiment, the kneading device 1 may be switchable between the rotor arrangement shown in Fig. 2 and the rotor arrangement shown in Fig. 3. Specifically, the kneading device 1 is capable of switching the relative rotational phase of the first rotor 50 and the second rotor 60 between a first rotor arrangement (Fig. 2) in which the first rotor 50 and the second rotor 60 rotate between the first rotation shaft 50a and the second rotation shaft 60a at a predetermined timing so that the first non-circular portion 53 and the second arc portion 61 face each other, and a second rotor arrangement (Fig. 3) in which the first rotor 50 and the second rotor 60 rotate between the first rotation shaft 50a and the second rotation shaft 60a at a predetermined timing so that the first arc portion 51 and the second arc portion 61 face each other. As an example, the rotor arrangement can be switched by temporarily disengaging a part (e.g., a gear) of a drive transmission path of at least one of the first rotor 50 and the second rotor 60, rotating one rotor 180 degrees around its axis, and then restoring the drive transmission path. As a result, it is possible to adjust the phase depending on the material to be kneaded and the process conditions. The effects of each phase (rotor arrangement) are the same as those described above.

[0101] A kneading device according to a first aspect of the present invention includes a kneading chamber that accommodates a material together with a working fluid in a supercritical or subcritical state in order to knead the material, a first rotor that is disposed inside the kneading chamber and rotates around a first rotation axis, and a second rotor that is disposed inside the kneading chamber and is disposed adjacent to and parallel to the first rotor and rotates around a second rotation axis in a direction opposite to the rotation direction of the first rotor. The first rotor includes a first outer peripheral portion that constitutes the outer periphery of the first rotor in a cross section of the first rotor perpendicular to the direction in which the first rotating shaft extends, and the first outer peripheral portion has a first arc portion and a first non-arc portion that is a portion of the first outer peripheral portion that is different from the first arc portion, and when a virtual circle that passes through the first arc portion and is centered on the first rotating shaft when viewed along the direction in which the first rotating shaft extends is defined as a first virtual circle, the first arc portion has an arc shape centered on the first rotating shaft, is positioned radially outermost of the first rotor, and extends circumferentially of the first rotor continuously for at least one-third of the total circumference of the first virtual circle. The second rotor includes a second outer peripheral portion that constitutes the outer periphery of the second rotor in a cross section of the second rotor perpendicular to the direction in which the second rotation shaft extends, and the second outer peripheral portion has a second arc portion and a second non-arc portion that is a portion of the second outer peripheral portion that is different from the second arc portion, and when a virtual circle that passes through the second arc portion when viewed along the direction in which the second rotation shaft extends and is centered on the second rotation shaft is defined as a second virtual circle, the second arc portion has an arc shape centered on the second rotation shaft, is positioned radially outermost on the second rotor, and extends circumferentially of the second rotor continuously for at least one-third of the total circumference of the second virtual circle, and the first rotor and the second rotor rotate between the first rotation shaft and the second rotation shaft at a predetermined timing so that the first non-arc portion and the second arc portion face each other.

[0102] A kneading device according to a second aspect of the present invention is the kneading device according to the first aspect, wherein, when the first rotor is viewed along a radial direction, the first non-circular portion has a shape twisted around the first rotation axis so as to extend in a direction inclined with respect to the first rotation axis, and when a length of the first rotor in the extending direction of the first rotation axis is defined as a first axis length L, a radius of the first virtual circle is defined as a first radius R, and an angle formed between the extending direction of the first rotation axis and the extending direction of the first non-circular portion is defined as a first twist angle θ, －1 (πR / 4L)≦θ≦tan －1 (πR / 2L) is satisfied.

[0103] A kneading device according to a third aspect of the present invention is a kneading device according to the first or second aspect, wherein the length of the first arc portion that extends continuously in the circumferential direction of the first rotor is 3 / 4 or less of the length of the entire circumference of the first virtual circle.

[0104] A kneading device according to a fourth aspect of the present invention is the kneading device according to the first to third aspects, wherein the relative rotational phase of the first rotor and the second rotor is switchable between a first rotor arrangement in which the first rotor and the second rotor rotate at a predetermined timing between the first rotating shaft and the second rotating shaft so that the first non-circular portion and the second arc portion face each other, and a second rotor arrangement in which the first rotor and the second rotor rotate at a predetermined timing between the first rotating shaft and the second rotating shaft so that the first arc portion and the second arc portion face each other.

Claims

1. A kneading device comprising: a kneading chamber that accommodates a material together with a working fluid in a supercritical or subcritical state in order to knead the material; a first rotor that is disposed within the kneading chamber and rotates about a first rotation axis; and a second rotor that is disposed within the kneading chamber, disposed adjacent to the first rotor in parallel with the first rotor, and rotates about a second rotation axis in a direction opposite to the rotation direction of the first rotor, wherein the first rotor includes a first outer periphery that constitutes the outer periphery of the first rotor in a cross section of the first rotor perpendicular to the extension direction of the first rotation axis, the first outer periphery having: a first arc portion; and a first non-arc portion that is a portion of the first outer periphery that is different from the first arc portion, the first arc portion has an arc shape centered on the first rotation shaft, is disposed radially outermost of the first rotor, and extends continuously in the circumferential direction of the first rotor for at least ⅓ of the total circumference of the first virtual circle; the second rotor includes a second outer circumferential portion constituting an outer circumferential portion of the second rotor in a cross section of the second rotor perpendicular to the direction in which the second rotation shaft extends, the second outer circumferential portion having a second arc portion and a second non-arc portion that is a portion of the second outer circumferential portion different from the second arc portion; and when a virtual circle that passes through the second arc portion when viewed along the direction in which the second rotation shaft extends and is centered on the second rotation shaft is defined as a second virtual circle, the second arc portion has an arc shape centered on the second rotation shaft, is disposed radially outermost of the second rotor, and extends continuously in the circumferential direction of the second rotor for at least ⅓ of the total circumference of the second virtual circle; A kneading device, wherein the first rotor and the second rotor rotate at a predetermined timing between the first rotating shaft and the second rotating shaft such that the first non-circular portion and the second circular portion face each other.

2. A kneading device according to claim 1, wherein, when the first rotor is viewed along a radial direction, the first non-circular portion has a shape twisted around the first rotation axis so as to extend in a direction inclined relative to the first rotation axis, and when a length of the first rotor in the extension direction of the first rotation axis is defined as a first axis length L, a radius of the first virtual circle is defined as a first radius R, and an angle between the extension direction of the first rotation axis and the extension direction of the first non-circular portion is defined as a first twist angle θ, then tan －1 (πR / 4L)≦θ≦tan －1 A kneading device that satisfies (πR / 2L).

3. A kneading device as claimed in claim 1 or 2, wherein the length of the first circular arc portion which extends continuously in the circumferential direction of the first rotor is 3 / 4 or less of the total circumference of the first imaginary circle.

4. A kneading device as described in claim 1 or 2, wherein the relative rotational phase of the first rotor and the second rotor can be switched between a first rotor arrangement in which the first rotor and the second rotor rotate at a predetermined timing between the first rotating shaft and the second rotating shaft so that the first non-circular portion and the second arc portion face each other, and a second rotor arrangement in which the first rotor and the second rotor rotate at a predetermined timing between the first rotating shaft and the second rotating shaft so that the first arc portion and the second arc portion face each other.

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