JPH0372934A - Apparatus for homogenizing dispersoid - Google Patents

Abstract

PURPOSE:To rapidly homogenize dispersoid in a medium by mounting an inert gas introducing pipe and a jet dispersing accelerating apparatus to a mixing tank. CONSTITUTION:A paint raw solution is supplied into a pressure-resistant container 1 from a supply pipe 3. Subsequently, nitrogen gas is supplied into the pressure-resistant container 1 from an inert compressed gas cylinder 4 through an inert compressed gas introducing pipe 5 and injected in the paint raw solution of the pressure-resistant container 1 from a blow-in nozzle 6. The injected nitrogen gas is dissolved in the paint raw solution to be dispersed as gas bubbles. A part of the undissolved nitrogen gas is discharged to the outside from a gas venting exhaust pipe 9. The pressure of the nitrogen gas is adjusted by a pressure reducing valve 7 and, the higher this pressure, the more the dispersing effect of the paint raw solution is enhanced. By this method, a dissolving speed is increased.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to an apparatus for homogenizing dispersoids used as pigments in paints, inks, cosmetics, foods, etc. in a medium.

<Prior Art> The constituent components of a paint are mixed and homogenized in an appropriate blending ratio depending on the intended use.

Among these, pigmented paints require a pigment dispersion step in which the pigment is uniformly mixed into a vehicle and the aggregated particles are separated into separate independent particles. Conventionally, ball mills, sand mills, and colloid mills are known as homogenizers used in this pigment dispersion process, that is, devices for uniformly dispersing pigments.

A ball mill is a rotating cylinder in which a large number of ceramic balls, steel balls, etc. are placed together with a pigment as a grinding medium, and the grinding of these balls is carried out. This is a device for crushing, mixing and dispersing pigments by blowing. A sand mill is a device in which 20 to 40 meshes of spherical sand are placed together with a pigment in a cylindrical container with an agitator separated by several plates, and the pigment is dispersed by the flow of the sand. Furthermore, a colloid mill is a device that supplies and disperses pigment into the gap between two discs that have different rotations.

<Problems to be Solved by the Invention> Such conventional dispersoid homogenizing devices have problems in that the homogenizing speed of pigments is slow and it takes a long time.

That is, in a ball mill or a sand mill, a grinding medium collides with pigment aggregates, and the impact force causes the aggregates to be broken and homogenized. However, the pigment concentration is usually about 30% by weight, which is not so high, and furthermore, since some of the pigment is aggregated, the actual concentration of pigment aggregates is even lower.

Therefore, if a pigment in such a state is to be homogenized by a ball mill or a sand mill, the grinding medium must collide with a low concentration of pigment, that is, with a small number of aggregates, and the probability of this is extremely low. Therefore, it is necessary to lengthen the residence time of the pigment in the container or to reduce the amount of treatment in one cycle, which slows down the homogenization speed of the pigment and takes a long time.

Furthermore, in a colloid mill, aggregates are destroyed and homogenized by supplying pigment to the gap between discs with different rotations, so the gap between the discs must be set very narrow. In fact, the diameter of the pigment particles is about 15 μm, and it takes a very long time to supply the pigment into this gap, and as mentioned above, the homogenization speed of the pigment becomes slow.
This will take a long time. In particular, for pigments with high viscosity, the homogenization speed becomes even slower.

Furthermore, it has been considered to use a mesh filter with very small openings, but the aggregation of particles would block the openings during processing, making continuous processing impossible.

Further, in each of the above-mentioned homogenizing devices, cleaning the device after use is troublesome and takes a long time. In particular, in recent years, there has been a need for common equipment that can be used repeatedly due to the demand for production of a wide variety of products in small quantities. Therefore, there is a need for a homogenizing device to homogenize different types of pigments one after another quickly using a common device.

However, in the ball mills and sand mills mentioned above, it is necessary to take out and wash the glass balls and sand as the grinding media supplied in the container each time they are used, and even in colloid mills, there is a relatively large amount of sand in the disk. It was necessary to clean a wide surface that came into contact with the liquid, making the work extremely troublesome.

The present invention is intended to solve these problems, and an object of the present invention is to provide a homogenization device that speeds up the homogenization work of dispersoids.

Means for Solving the Problems> A dispersoid homogenizing device of the present invention for achieving the above-mentioned object comprises: a mixing tank in which a liquid dispersion medium and a dispersoid are accommodated as a mixed liquid; An inert pressurized gas introduction pipe connected to the pipe and having a tip thereof protruding into the mixed liquid, and an ejection dispersion promoting device that communicates with the mixing tank and ejects the mixed liquid into a low-pressure space. That is.

Effect〉 Inert pressurized gas is blown into the mixture of the liquid dispersion medium and the dispersoids dispersed in a coagulated state in the liquid from the inert pressurized gas introduction pipe, and this gas is dissolved in the mixture, Alternatively, it is dispersed as bubbles. After that, it enters the jet dispersion accelerator,
It is ejected into a low pressure space. Due to the rapid pressure reduction at this time, the inert gas that was dissolved or present as bubbles rapidly expands, shearing and crushing the aggregated particles of the dispersoid.

Embodiments Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

Fig. 1 is a schematic diagram of a dispersoid homogenizing device according to an embodiment of the present invention, Fig. 2 is an enlarged cross-sectional view of the part ■ in Fig. 1, and Fig. 3 is a state of homogenization by the homogenizing device of the present invention. This is a graph representing

As shown in FIG. 1, 1 is a pressure-resistant container serving as a mixing tank, and a lid 2 is attached to the upper part of the container. A supply pipe 3 to which a dispersion system in which a dispersoid and a liquid dispersion medium are mixed is connected to the pressure vessel 1 of B. 4 is an inert pressurized gas cylinder, and the inside thereof is filled with nitrogen gas as an inert pressurized gas.

The base end of an inert pressurized gas introduction pipe 5 is connected to the inert pressurized gas cylinder 4, and the tip thereof is connected to the pressure container 1 and enters the inside, and a blowing nozzle 6 is attached thereto.

A pressure reducing valve 7 and an on-off valve 8 are installed in the middle of the inert pressurized gas introduction pipe 5. Further, a gas discharge pipe 9 is connected to the pressure vessel 1 .

The bottom of the pressure vessel 1 is connected to the base end of a discharge pipe 10 through which the above-mentioned dispersed system is discharged, and the tip of the discharge pipe 10 is connected to the bottom of the pressure vessel 1 to inject the dispersed system containing the dispersoids in the pressure vessel 1 to the outside through an on-off valve 11. A dispersion promoting bag [12] is connected to the dispersion promotion bag [12].

As shown in FIG. 2, this jet dispersion promoting device 12 has a cylindrical main body 13, an orifice plate 14, a collided member 15, etc. It has an injection hole 16 on the side of the main body 131f,
Its upper outer periphery is screwed into the lower part of the discharge pipe 10. The orifice plate 14 is fixed to the upper part of the main body 13, and has a nozzle 17 formed in the center. The collided member 15 is the main body 13
It is inserted into the interior of the orifice plate 14 with a gap between it and the inner wall thereof and close to the nozzle 17 of the orifice plate 14, and its lower part is screwed into the lower inner periphery of the main body 13. An operating section 18 is attached to the lower part of the collided member 15, and by moving the operating section 18 together, the distance between the collided member 15 and the orifice plate 14 can be adjusted.

An injection nozzle 19 is provided in the injection hole 16 of the injection dispersion promoting device 12.
is connected. A container 20 is arranged below the tip of the injection nozzle 19.

The operation of the dispersoid homogenizing device of the present embodiment described above will be explained by taking as an example the case where pigments in a paint are homogenized.

A paint stock solution as a dispersion system is produced by mixing a dispersoid, that is, a pigment such as calcium carbonate, titanium white, barium sulfate, etc., with a liquid dispersion medium such as Fes, toluene, or xylene. The primary particle size of this pigment is originally very small, for example, 1 μm or less, but secondary agglomerated Ili, Is forms of the pigment are present in the paint stock solution, and the particle size is 1 μm or less. For example, some particles exceed 100 μm, and it is necessary to disperse and homogenize them to maintain product quality.

Therefore, as shown in FIG. 1, first, a roughly mixed paint stock solution is supplied from the supply pipe 3 into the pressure spring mold 1. next,
Nitrogen gas is supplied from an inert pressurized gas cylinder 4 into the pressure container 1 through an inert pressurized gas introduction pipe 5, and is injected into the paint stock solution in the pressure container 1 from a blow nozzle 6 at the tip. The injected nitrogen gas is dissolved in the paint stock solution, and a portion is dispersed in the form of bubbles.

Then, this partially undissolved nitrogen gas is discharged to the outside from the gas extraction exhaust pipe 9. In this way, by continuously injecting nitrogen gas into the paint stock solution, the paint stock solution is stirred and the dissolution rate can be increased.

The pressure of the nitrogen gas supplied from the inert pressurized gas cylinder 4 is regulated by the pressure reducing valve 7, and the higher the pressure, the better the dispersion effect of the paint stock solution. However, the increase in pressure above the necessary equipment leads to an increase in nitrogen consumption and the need for heavier equipment in the pressure vessel 1.
0 kg/at7 is appropriate, but it is not limited to this.

Further, although nitrogen gas is used as the inert pressurized gas, any inert gas that does not react with the liquid dispersion medium such as varnish, toluene, xylene, etc. may be used.

The raw paint solution in the pressure container 1 stirred by nitrogen gas is discharged into the discharge pipe 1 by operating the on-off valve 11.
0 to the jet dispersion promoting device 12. As shown in FIG. 2, the paint solution supplied to the jet dispersion accelerator 12 is increased in flow velocity by the orifice plate 14, passes through the nozzle 17, and collides with the upper part of the collided member 15.

This collision force destroys the secondary aggregates in the stock solution and homogenizes it.

In addition, at this time, nitrogen gas is dissolved or dispersed as bubbles in the paint stock solution under high pressure, so when this paint stock solution is injected into the main body 13, it is released to the atmosphere and the liquid is instantly released. Nitrogen gas expands and dissipates, impacting the paint solution. By effectively applying a shearing force to the secondary agglomerated aggregates by this fighting force, dispersion by breaking the aggregates in the stock solution is promoted.

Then, the homogenized paint stock solution is then transferred to the injection hole 16.
It is supplied to the injection nozzle 19 from the injection nozzle 19, and is discharged from the tip of the injection nozzle 19 into the container 20.

The results of homogenization of the paint stock solution by the homogenization device of this example will be explained with reference to FIG.

A stock solution of a white paint, which is a mixed solution of calcium carbonate, titanium white, and barium sulfate as pigments and Fes as a liquid medium, contains secondary aggregates with a maximum diameter of 100 μm or more. Then, this paint stock solution was subjected to dispersion treatment five times in succession using the homogenization device of this example described above. In this case, the pressure of nitrogen gas supplied into the pressure vessel 1 is 100 kg/cd, and the orifice plate 1 is
1) The diameter of the nozzle 17 of No. 4 was 0.65 mm.

As shown in Figure 3, one secondary aff whose maximum diameter was 100 μm or more before treatment had a diameter of 3 μm after one treatment.
By increasing the number of treatments, it was further reduced to 15 μm after five treatments.

In addition, Figure 3 shows the results of homogenization in a comparative example in which the same equipment as in the previous example was used, the blow nozzle 6 was shortened, and nitrogen gas was supplied to the top of the paint stock solution filled in the pressure container 1. Shown below.

In this case, according to actual measurements, the amount of nitrogen gas dissolved in the paint stock solution was 1/10 of that in the above-mentioned example, and the secondary R aggregate was 1/10.
Its diameter is 50 Itm after 5 treatments, and 3 Itm after 5 treatments.
It was reduced only to 0 μm. This means that the efficiency of reducing secondary aggregates is reduced compared to the previous embodiments. This shows that dissolving nitrogen gas in the paint stock solution and dispersing it as bubbles is more effective for homogenization.

In the above embodiment, only one nozzle 17 is provided on the orifice plate 14 of the ejection dispersion promoting device 12 attached to the bottom of the pressure vessel 1, but a plurality of nozzles 17 may be provided to speed up the processing. .

FIG. 4 is a schematic diagram of a dispersoid homogenization device according to another embodiment of the present invention, FIG. 5 is an enlarged sectional view of the v section of FIG. 4, and FIG. 6 is a homogenization by the homogenization device of the present invention. It is a graph representing the state. Note that the same members as those in the previous embodiment are given the same reference numerals and redundant explanations will be omitted.

As shown in FIG. 4, a discharge pipe 10 is provided at the bottom of the pressure vessel 1.
The proximal end of the pressure vessel 1 is connected to the dispersion promotion device 3°, which injects and disperses the dispersion system inside the pressure vessel 1 to the outside via an on-off valve 11.

As shown in detail in FIG. 5, this jet dispersion promoting device 30 includes a nozzle 31, a cylindrical body 32, and a needle valve 3.
It has 3. The nozzle 31 is screwed into the tip of the discharge pipe 10. The main body 32 has an injection hole 34 on the side, and the inner circumference of the upper part thereof is screwed into the lower part of the nozzle 31. The needle valve 33 has a tapered tip and is inserted into the discharge port of the nozzle 31, and its lower part is screwed into the lower part of the main body 32.

An operating section 35 is attached to the lower part of the needle valve 33, and by rotating the operating section 35 and moving the needle valve 33 up and down, the needle valve 33 and the nozzle 3
The gap 36 between the discharge port 1 and the discharge port 1 can be adjusted.

Next, the operation of the dispersoid homogenizing device of this embodiment described above will be explained.

As shown in FIG. 4, first, similarly to the above-mentioned embodiment,
The paint stock solution is supplied from the supply pipe 3 into the pressure container 1, and nitrogen gas is supplied from the inert pressurized gas cylinder 4 into the pressure container 1 via the inert pressurized gas introduction pipe 5, and from the blow nozzle 6 at the tip. Spray into the paint solution. The injected nitrogen gas is dissolved in the paint stock solution, and a portion is dispersed in the form of bubbles.

By continuously injecting nitrogen gas into the paint stock solution in this way, the paint stock solution is stirred and the dissolution rate can be increased.

Next, the paint stock solution in the pressure container 1, which has been stirred by nitrogen gas, is supplied to the ejection dispersion promoting device 30 via the discharge pipe 10. As shown in FIG. 5, the paint stock solution supplied to the jet dispersion promoting device 30 is injected into the main body 32 through the gap 36 between the outlet of the nozzle 31 and the needle valve 33. At this time, the flow rate of the paint solution passing through the gap 36 increases and the nozzle 3
By being injected from 1, secondary agglomerated aggregates in the stock solution are destroyed and homogenized by this particle shearing force.

In addition, when the nitrogen gas dissolved or dispersed as bubbles in the paint stock solution is released to the atmosphere during injection, the nitrogen gas in the liquid instantly expands and dissipates, giving an impact to the paint stock solution, and this impact force causes By effectively applying shear force to the secondary aggregates, the dispersion of the aggregates in the stock solution is promoted.

Note that the gap 36 between the discharge port of the nozzle 31 and the needle valve 33
The larger the particle diameter, the greater the throughput, but large particle size aggregates also pass through this gap 36, making it impossible to homogenize them. Therefore, the smaller the gap 36 is, that is, the closer it is to the primary particle diameter of the pigment, the better the screening effect will be and the more uniform the treatment can be.
A value of about m is effective. However, the paint undiluted solution
Conventionally, when passing through the gap 36, aggregates larger than the gap 36 may not be able to pass through and end up blocking this gap. However, in this example, as mentioned above, the nitrogen gas dissolved or dispersed as bubbles in the paint stock solution is exposed to the atmosphere and instantly swells and dissipates, giving an impact to the paint stock solution and causing the condensation. Disperse the agglomeration. Therefore, the gap 36
The large-diameter aggregates blocking the gap 36 will be broken and passed through, and the gap 36 will be unblocked.

Then, the homogenized paint stock solution is discharged into the container 20 by the injection nozzle 19.

The results of homogenization of the paint stock solution by the homogenization device of this example will be explained with reference to FIG.

Note that the pressure of nitrogen gas supplied into the pressure vessel 1 is set to 50
kg/crl, and the gap 36 was 36 μm.

As shown in Figure 6, secondary aggregates with a large diameter of 100 μm or more before treatment have a diameter of 30 μm after one treatment.
m, which was further reduced by increasing the number of treatments, and was reduced to 20 μm after three treatments. Note that during this process, the aggregate did not block the gap 36, and the process could be performed continuously.

In addition, using the same equipment as in the previous embodiment, the blowing nozzle 6 is shortened and nitrogen gas is supplied to the top of the paint stock solution filled in the pressure container 1, immediately after the start of the treatment. The aggregates blocked the gaps 36, making it impossible to homogenize the paint layer. This shows that dissolving nitrogen gas in the paint stock solution and dispersing it as bubbles is more effective for homogenization.

In the above-described embodiment, one ejection dispersion promoting device 30 attached to the bottom of the pressure vessel 1 is provided, but a plurality of devices may be provided to speed up the processing.

<Effects of the Invention> Hereinafter, as described in detail with reference to Examples, according to the dispersoid homogenizing apparatus of the present invention, a mixing tank in which a liquid dispersion medium and a dispersoid are accommodated as a mixed liquid. An inert pressurized gas introduction pipe connected to the mixing tank and having a tip protruding into the mixed liquid, and an ejection dispersion promoting device that injects the mixed liquid in the mixing tank into a low-pressure space, and is equipped with a liquid dispersion medium. The inert pressurized gas is dissolved or dispersed in the form of bubbles inside the mixed liquid of the dispersoid in the agglomerated state and is injected into the low-pressure space by the jet dispersion accelerator.
When the mixed liquid is injected into the low-pressure space, the inert pressurized gas that was dissolved or existed as bubbles expands and breaks up the aggregated particles of the dispersoid, which increases the homogenization processing speed and makes the dispersoid homogeneous. It is possible to speed up the conversion work.

Furthermore, as a result, the device becomes extremely simple and compact, and it becomes easy to clean, making it possible to use the device with different types of paints.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram of a dispersoid homogenizing device according to an embodiment of the present invention, Fig. 2 is an enlarged cross-sectional view of the part ■ in Fig. 1, and Fig. 3 is a state of homogenization by the homogenizing device of the present invention. Graph representing 4th
The figure is a schematic diagram of a dispersoid homogenizing device according to another embodiment of the present invention, FIG. 5 is an enlarged sectional view of the V section of FIG. 4, and FIG. This is a graph representing In the drawing, 1 is a pressure container (mixing tank), 4 is an inert pressurized gas cylinder, 5 is an inert pressurized gas introduction pipe, 6 is a blowing nozzle, and 12.30 is an ejection dispersion promoting device.

Claims (1)

[Claims] a mixing tank containing a liquid dispersion medium and a dispersoid as a mixed liquid; an inert pressurized gas introduction pipe connected to the mixing tank and having a tip end protruding into the mixed liquid; and communicating with the mixing tank. and a jet dispersion promoting device which jets the liquid mixture into a low pressure space.