Treatment apparatus for highly viscous fluid

Abstract

 A treatment apparatus for production of solid/liquid type treatment materials in chemistry, medicines, electronics, ceramics, foods, feed or the like, which conducts a mixing and kneading, kneading or dispersion treatment of a highly viscous paste preliminaxily mixed and kneaded having a viscosity range of 10 to 2,500 dPa · s, without using dispersion media or beads. This treatment apparatus comprises a vessel having a supply port and a discharge port of treatment materials, and a rotating body rotatably disposed in the vessel. An annular fine gap is formed between an inner face of the vessel and an outer periphery face of the rotating body for passage of the treatment materials, while being subject to the treatment by the rotating body. The surface of the rotating body which faces the fine gap is provided with notches formed by a knurling process.

Description

FIELD OF THE INVENTION

[0001] The present invention relates to a treatment apparatus for a highly viscous fluid, by which solid/liquid-type treatment materials in various fields such as chemistry, medicines, electronics, ceramics, foods or feed, can be pulverized by a liquid-passing treatment without using dispersion media or beads.

BACKGROUND INFORMATION

[0002] When solid/liquid-type highly viscous fluid of from a low viscosity to a high viscosity (10 to 2,500 dPa · s) regardless of oiliness or aqueousness is subjected to a mixing and kneading, kneading or dispersion treatment, particularly in a system to which nanopowder is incorporated, formation of a so-called hard agglomerate or agglomerate as partial aggregation of powder is observed. Accordingly, such a treatment is often conducted through a dispersion step by a bead mill using dispersion media or beads as described in, for example, JP-A-3-178326. Since the bead mill has such a structure that treating materials are mixed with dispersion media or beads in a vessel, the mixture is stirred by a rotator which rotates in the vessel, and dispersion is carried out by a shearing or impact action caused by the dispersion media, the dispersion media may sometimes be abraded or damaged by impact or friction caused by stirring motion. Contamination thereby caused may be incorporated into the treatment materials, and undesired result in view of quality may possibly be caused. In addition, large power is needed to move the dispersion media, and it is also required to pass the mixture through a media-separating apparatus (separator) to separate the dispersion media from the treatment materials after the treatment, whereby internal resistance is increased. As the results, high energy has been demanded to drive the bead mill. Here, JP-A-2007-125518 proposes a treatment apparatus using no beads. In the treatment apparatus described in this publication, the surface of a rotator is formed to be smooth, the treatment materials cause slippage when the treatment materials are a highly viscous fluid, whereby it becomes difficult to apply high shearing stress to the materials and it is sometimes difficult to conduct sufficient dispersion treatment.

SUMMARY OF THE INVENTION

[0003] It is an object of the present invention to provide a treatment apparatus for a highly viscous fluid which is capable of conducting a mixing and kneading, kneading or dispersion treatment of a highly viscous fluid at low energy without using dispersion media or beads, securely conducting the treatment without causing slippage, and uniformly dispersing them without hard agglomerate or agglomerate.

[0004] In view of such circumstances, the present inventors have focused on a wet-type media dispersing machine or bead mill of a so-called annular type as described in, for example, the above-mentioned JP-A-3-178326, found such a structure that is possible to conduct pulverization of particles without forming hard agglomerate or agglomerate even when no dispersion media or beads are used, and accomplished the treatment apparatus as explained below.

[0005] That is, the treatment apparatus of the present invention is a treatment apparatus for production of solid/liquid type treatment materials, which conducts a mixing and kneading, kneading or dispersion treatment of treatment materials of a highly viscous fluid preliminarily mixed and kneaded having a viscosity range of 10 to 2, 500 dPa · s, without using dispersion media. This treatment apparatus comprises a vessel having a supply port and a discharge port of treatment materials, a rotating body rotatably disposed in the vessel, and an annular fine gap formed between an inner face of the vessel and an outer periphery face of the rotating body for passage of the treatment materials, while being subject to the treatment by the rotating body, wherein the rotating body has a surface on which notches are formed.

[0006] The notches are formed on the surface of the rotating body by preferably applying a knurling process. When the rotating body is formed in a tubular body having a circular cross-section, the notches are formed over the outer periphery face in its entirety. When the rotating body is formed in a tubular body with a modified cross-section by providing groove potions at intervals in a circumferential direction on the outer periphery face to form tooth-like projections extending in a longitudinal direction, the notches are formed on the outer periphery face of the tooth-like projections.

[0007] The effective or apparent surface area of the rotating body is expanded by the notches than the surface area of a smooth face. The roughening rate of this instance i.e. the ratio of the effective or apparent surface area to a projected surface area on a horizontal face is preferably about. 1.05 to 2.35. The above annular fine gap is preferably about 1.0 to 10 mm.

[0008] In the above-mentioned structure, an annular fine gap is formed between an inner face of the vessel and an outer periphery face of the rotating body for passage of the treatment materials, while being subject to the treatment by the rotating body, and notches are formed on the surface of the rotating body which faces the annular fine gap, whereby the effective surface area of the rotating body can be substantially increased and at the same time, its friction coefficient can be increased. Therefore, a high shearing stress can be applied to the treatment materials being under passing between the annular fine gap without slippage of the rotating body, and the shearing rate can be lowered. Further, since no dispersion media or beads are used, the internal pressure of the vessel can be lowered and there is no influence of contamination by abrasion of dispersion media or the like. Since there is no necessity of the media-separating apparatus or separator, it is possible to conduct the dispersion treatment efficiently at low energy.

[0009] By providing groove portions at intervals in a circumferential direction on the outer periphery face of the rotating body to form tooth-like projections extending in a longitudinal direction, the treatment materials are subjected to compression and shearing actions at the notches formed on the tooth-like projections and to release and expansion actions at the groove portions between the projections at which no notches are provided. And, the treatment materials are repeatedly subjected to the compression and shearing actions and the release and expansion actions while the materials flow from the supply port towards the discharge port side. Accordingly, a dispersion treatment by compression, shearing and expansion can be made as if the materials are treated by a dispersion treatment with a roll mill, and uniform pulverization can be further securely made.

[0010] The roughening rate (r) on the surface of the rotating body on which the notches are provided, is adjusted to be about 1.05 to 2.35, preferably about 1.15 to 1.55. If the roughening rate is higher than 2.35, the stirring resistance becomes high, large power is required, a phenomenon of sticking of the treatment materials to the surface of the rotating body is seen, and it becomes difficult to control the temperature of the treatment materials. If the roughening rate is lower than 1.05, in a case where the treatment materials are of the upper limit side of the viscosity range of the highly viscous fluid as the subject of the present invention, a slippage phenomenon or an accompanying rotation phenomenon by clogging is seen, whereby it becomes difficult to conduct the dispersion treatment efficiently. Further, the annular fine gap is formed to be about 1.0 to 10 mm, preferably about 2.0 to 5.0 mm. If this gap is too small, the flow resistance becomes large, large driving power is required, whereas if the gap is too large, it becomes impossible to prevent formation of hard agglomerate or agglomerate.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011] 

Fig.1 shows an example of the present invention and is a front view showing a vessel portion in cross-section.

Fig.2 shows an example of a rotating body and is a side view of a rotating body with a circular cross-section.

Fig.3 shows another example of a rotating body and is a side view of a rotating body having tooth-like projections.

Fig.4 is an explanatory plane view showing an example of notches.

Fig.5 is an explanatory plane view showing another example of notches.

Fig.6 is an explanatory plane view showing a further example of notches.

Fig.7 is an enlarged explanatory cross-section of notched portion.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] The present invention can be applied to pulverization of solid/liquid-type treatment materials in various fields such as chemistry, medicines, electronics, ceramics, foods or feed. As shown in Fig.1, the treatment apparatus of the present invention has a vessel 1 and a rotating body or rotor 2 which rotates in the vessel. The vessel 1 communicates to a supply port 3 and a discharge port 4 for the treatment materials such as highly viscous slurry, and is provided with a jacket 5 through which temperature-controlling media such as cooling water are flown around the vessel, and the jacket 5 is provided with a flow inlet 6 and a flow outlet 7 for the temperature-controlling media. The rotating body 2 is rotated by a driving shaft 9 which is connected to a driving motor (not shown) through a mechanical seal 8.

[0013] An annular fine gap 10 is formed between an inner wall face of the vessel 1 and an outer periphery face of the rotating body 2. Treatment materials supplied into the vessel 1 from the supply port 3 by use of a supply pump (not shown) are flown towards the discharge port and stagnate in the annular fine gap 10. The size of the annular fine gap 10 is about 1.0 to 10 mm, preferably about 2.0 to 5.0 mm. The treatment materials to be supplied into the vessel are optimally a highly viscous paste within a viscosity range of about 10 to 2,500 dPa · s. If it is less than 10 dPa · s, the viscosity is too low and brings about insufficient shearing stress unless the rotation rate of the rotating body is maximized. If it is a highly viscous paste with a viscosity higher than 2,500 dPa · s, the viscous resistance is too high, large driving power for driving the rotating body is required and heat generation becomes high, whereby it becomes impossible to conduct normal temperature control.

[0014] In the apparatuses shown in Fig.1 and Fig.2, the rotating body 2 is formed in a tubular shape of a circular cross section. In this structure, the treatment materials continuously receive compression and shearing actions by the rotation of the rotating body. Further, in the example shown in Fig.3, the rotating body is formed in a tubular body with a modified cross-section by providing groove portions 11 at intervals in a circumferential direction on the outer periphery face to form tooth-like projections 12 extending in a longitudinal direction of the rotating body. In this structure, the treatment materials are subjected to compression and shearing at the tooth-like projections and release and expansion at the groove portions, and receive these actions repeatedly and then are discharged from the discharge port.

[0015] Notches 13 are formed on the outer periphery face in its entirety when the rotating body 2 is formed to have a circular cross section or on the surface of the tooth-like projections 12 when the rotating body is formed to have a modified cross section. The notches 13 are preferably formed by a knurling process. The shape of the notches 13 is formed to have horizontal lines as shown in Fig.1, a parallel knurl such as oblique lines as shown in Fig.4, or a twill knurl form such as rectangular, cross or diagonal as shown in Fig.5 and Fig.6. Further, fine projections 14 formed by the notches are formed to have a height of about 1.0 to 0.1 mum, preferably about 0.6 to 0.3 mm. The height depends on the size of secondary aggregation contained in the solid/liquid type treatment materials, but when the height is about 1.0 mm or higher, large driving power is required and temperature control becomes difficult. Moreover, when the height is about 0.1 mm or lower, accompanying rotation phenomenon by clogging is seen at the upper limit side of the viscosity range. The fine projections 14 formed by the notches 13 are formed in various shapes.. For example, in the case of rectangular fine projections as shown in Fig.7, an angle α of a slope of a dent defined by the fine projections 14 is about 90 degrees, the distance d between peaks of the projections is about 1 mm, and the height is about 0.5 mm.

[0016] By forming the notches 13 on the surface of the rotating body 2, the effective surface area of the rotating body 2 becomes larger than the surface area of a rotating body of a smooth face on which no notches are formed. The degree of increment of the surface can be represented by a roughening rate (r) i.e. the ratio of the effective or apparent surface area to a projected surface area on a horizontal face. And, in the present invention, the notches are formed so that the roughness rate (r) of the surface of the rotating body would become r>1, preferably r = about 1.05 to 2.35, particularly preferably r = about 1.15 to 1.55. By doing so, the effective or apparent surface area of the rotating body is increased by r times as compared with the surface area of a conventional rotating body having a smooth face, the contact area with the treatment materials can be increased, and the shearing stress can securely be applied reflecting the increase. In a case where the powder particles contained in the treatment materials are particles of a high hardness, when the inner wall face of the vessel and the rotating body which are used in contact with the treatment materials are ceramics, the ceramics may be of a coarse-surface ceramic material for which surface treatment has not been made. Particularly, the surface of the rotating body has a roughening rate (r) of about 1.05 to 2.35 as compared with the surface of normal ceramics for which a surface treatment has been made, and therefore such a coarse-surface ceramic material may be used as it is.

[0017] The circumferential velocity rotational speed of the rotating body is desirably within a range of about 3 to 30 m/sec, preferably about 5 to 25 m/sec. It is advisable to operate the rotating body under such condition that the temperature of the treatment materials is 60°C or lower to the utmost. If the circumferential velocity is less than 3 m/sec, the shearing stress is insufficient, the treatment materials pass through the annular fine gap without treatment by the rotating body, and no dispersion action is applied, thereby receiving substantially no dispersion effect. Further, if the circumferential velocity is 30 m/sec or higher, large driving force is required and heat generation becomes high, and it becomes difficult to keep the temperature of the treatment materials at 60°C or lower even if the viscosity is adjusted, thereby bringing about deterioration of properties of the treatment materials and adverse influence on the product quality.

Example 1

[0018] A high viscosity paste having a white pigment mixed and kneaded into an epoxy type adhesive was treated by an apparatus using no beads as shown in Fig.1. The annular fine gap between the inner wall face of the vessel and the outer periphery face of the rotating body was 2 mm. On the surface of the rotating body, notches having fine projections as shown in Fig.7 of which the angle of slopes was 90 degrees, the shape was square in plan view and the height was 0.5 mm, were formed by twill knurling. The roughening rate of the rotating body was about 1.45. The viscosity of the paste was 2,000 dPa · s, and when the circumferential velocity of the rotating body was 10 m/sec, the particle size of the obtained paste was 10 µm.

Example 2

[0019] A high viscosity paste having fillers mixed and kneaded into an epoxy type adhesive was treated by an apparatus using no beads as shown in Fig.1. The mean particle diameter at this time was 60 to 70 µm (rough particle diameter: 90 µm). The annular fine gap between the inner wall face of the vessel and the outer periphery face of the rotating body in this apparatus was 5 mm. On the surface of the rotating body, notches having fine projections of which the angle of slopes was 60 degrees, the shape was square in plan view and the height was 0.5 mm, were formed by twill knurling. The roughening rate of the rotating body was about 2.00. The viscosity of the paste was 2,020 dPa · s, and when the circumferential velocity of the rotating body was 10 m/sec, the particle size was 10 µm, and the treatment time was about a half of a conventional bead mill.

Example 3

[0020] A high viscosity paste having a plastic colorant and a white pigment mixed and kneaded was treated by an apparatus using no beads as shown in Fig.1. The annular fine gap between the inner wall face of the vessel and the outer periphery face of the rotating body was 5 mm. On the surface of the rotating body, notches having fine projections as shown in Fig.7 of which the angle of slopes was 90 degrees, the shape was square in plan view and the height was 0.5 mm, were formed by twill knurling. The roughening rate on the surface of the rotating body was about 1.45. The viscosity of the paste was 260 dPa · s, and when the circumferential velocity of the rotating body was 15 m/sec, the particle grain size was 30 µm.

[0021] As mentioned above, in the apparatus of the present invention, fine notches are formed on the surface of the rotating body by a knurling process, by which the roughening rate (r) of the surface of the rotating body which is used in contact with the treatment materials is made more than 1. By doing so, the effective or apparent surface area of the rotating body becomes r times the surface area of a rotating body having a smooth face, by which the contact area is increased and at the same time, the friction coefficient can be increased to prevent slippage, whereby the shearing stress from the rotating body can be sufficiently transmitted to the treatment materials and efficient dispersion can be conducted.

Claims

1. A treatment apparatus for a highly viscous fluid for production of solid/liquid type treatment materials, which conducts a mixing and kneading, kneading or dispersion treatment of treatment materials of a highly viscous fluid preliminarily mixed and kneaded having a viscosity within a range of 10 to 2,500 dPa · s, without using dispersion media, which comprises a vessel having a supply port and a discharge port of treatment materials, a rotating body rotatably disposed in the vessel, and an annular fine gap formed between an inner face of the vessel and an outer periphery face of the rotating body for passage of the treatment materials, while being subject to the treatment by the rotating body, wherein the rotating body has a surface on which notches are formed.

2. The treatment apparatus for a highly viscous fluid according to Claim 1, wherein the rotating body is formed in a tubular shape having a circular cross section, and the notches are formed on the surface of the rotating body by applying a knurling process.

3. The treatment apparatus for a highly viscous fluid according to Claim 1, wherein the rotating body is formed in a tubular shape on which groove portions are provided at intervals in a circumferential direction on the outer periphery face to form tooth-like projections extending in a longitudinal direction, and the notches are formed on the outer periphery face of the tooth-like projections by a knurling process.

4. The treatment apparatus for a highly viscous fluid according to any one of Claims 1 to 3, wherein the surface of the rotating body has a roughening rate of 1.05 to 2.35.

5. The treatment apparatus for a highly viscous fluid according to any one of Claims 1 to 4, wherein the annular fine gap is 1.0 to 10 mm.

6. The treatment apparatus for a highly viscous fluid according to any one of Claims 1 to 5, wherein the circumferential velocit.y of the rotating body is 3 to 30 m/sec.

Drawing