JPH0662885B2 - Preparation method of particle slurry - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for preparing a particle slurry in which particles are dispersed in a liquid medium.

[Prior art and its problems]

In recent years, the progress in the production technology of inorganic fine particles has been remarkable, and so-called submicron-sized ultrafine particles have been industrially produced. However, in general, the smaller the particle size of the solid particles, the higher the surface energy and the cohesive force between the particles, and therefore it is also well known that it is difficult to finely disperse fine solid particles into primary particles. ing. In order to disperse solid particles in a liquid medium, a dispersion device such as a colloid mill, a high-speed stirrer, or an ultrasonic disperser is used. However, there is a problem that the aggregated particles remain even when the dispersion treatment is performed for a long time because the aggregated particles cannot be released.

On the other hand, as a method of dispersing a pigment in a liquid medium or reducing the particle size, for example, US Pat.
A so-called sand mill is proposed in No. 156.

This method can give strong shearing energy during dispersion, and can disperse fine solid particles in a liquid medium, but a large number of aggregated particles remain, and the aggregated particles can be filtered by a method such as slurry. However, in this case, there is a problem that a large filtration area is required for filtering the slurry.

Further, if the dispersion time is increased to reduce the number of agglomerated molecules as much as possible, there is a problem that the primary particles are pulverized, the particle size distribution is widened, and the stirring blades are worn, so that the slurry is contaminated. .

[Object of the Invention]

The object of the present invention is to improve the above-mentioned drawbacks of the prior art, to deagglomerate the fine particles in the slurry while suppressing the crushing of primary particles, and to efficiently prepare a slurry of good color tone. It is about.

[Structure of Invention]

The above-described object of the present invention is to disperse particles in a liquid to prepare a particle slurry, which has an average primary particle diameter of 10 to 5000 times the average primary particle diameter of dispersed particles (A), and an average particle diameter. With a particle (B) having a particle size of 1.0 mm or less at a stirring speed represented by the following formula (I), and then separating from the slurry of the particle (B) and the particle (A). .

100 ≦ V / D ≦ 4000 (I) [wherein V represents the maximum peripheral velocity (m / sec) of stirring, and D represents the average diameter (mm) of the particles (B). ] It can be achieved by

The solid particles (A) used in the present invention include metal oxides such as titanium dioxide, silica, alumina, zirconia and titanium monoxide, complex oxides such as kaolinite, talc and zeolite, calcium carbonate, magnesium carbonate and the like. Phosphates such as carbonates, calcium phosphates, lithium phosphates,
Examples thereof include sulfates such as calcium sulfate and barium sulfate, nitrides such as titanium nitride, metal powders such as cobalt, iron and nickel, inorganic compounds such as activated carbon and pigments.

The slurry solvent used in the present invention, water, methanol, ethanol, alcohol such as ethylene glycol,
Examples thereof include ketones such as acetone and methyl ethyl ketone, hydrocarbons such as toluene, xylene, pentane and hexane, and esters such as ethyl acetate and butyl butyrate.

The concentration of the slurry is preferably 0.5 to 50% by weight, more preferably 2 to 40% by weight, most preferably 3 to 30% by weight. When the concentration of the slurry is too high, the viscosity of the slurry becomes large and the stirring power becomes high, which is not preferable. On the other hand, if the slurry concentration is too low, the dispersion efficiency will decrease, which is not preferable.

In the present invention, the solid particles (A) to be dispersed are stirred together with the particles (B) having a particle diameter 10 to 5000 times the average primary particle diameter of the solid particles and having an average particle diameter of 1.0 mm or less to form a slurry. Prepare.

As the particles (B), ceramics such as alumina, zirconia and titania, and particles such as glass and steel are used. Of these, ceramics and glass spheres are preferable.

The particle size of the particles (B) is required to be 10 to 5000 times the average primary particle size of the solid particles (A) to be dispersed, and 1.0 mm or less.

When the average particle size of the particles (B) is larger than 5000 times the average primary particle size of the solid particles (A) to be dispersed, the dispersibility of the solid particles (A) is not sufficient, and the solid particles (A) cannot be pulverized. This causes problems such as broadening of the primary particle size distribution. When the average diameter of the particles (B) is smaller than 10 times the average primary particle diameter of the dispersed solid particles (A), it becomes difficult to separate the particles (B) from the slurry of the solid particles (A), and This is not preferable because it causes a problem such that particles (B) are mixed in the particles. The average diameter of the particles (B) is preferably 15 to 4000 times, more preferably 20 to 3000 times, the average primary particle diameter of the dispersed solid particles (A).

Furthermore, the average diameter of the particles (B) must be 1.0 mm or less. 50 of the solid particles (A) in which the particles (B) are dispersed
If the average diameter is larger than 1.0 even if it has an average diameter smaller than 00 times, the dispersed solid particles (A) are broken, and ultrafine particles are generated, which results in a wide particle size distribution. However, there is a problem that the stirring blades are worn and the slurry is contaminated, which is not preferable.

The average diameter of the particles (B) is preferably less than 0.4 mm, more preferably less than 0.3 mm, most preferably less than 0.1 mm. The amount of the particles (B) used is preferably 5 to 0.1 times, more preferably 4 to 0.3, and most preferably 3 to 0.5 times the volume of the slurry. If the amount of particles (B) used is less than 0.1 times the capacity of the slurry,
Not enough dispersibility. On the other hand, if it exceeds 5 times by volume, the fluidity at the time of stirring becomes poor and stirring becomes difficult, which is not preferable.

In the method of the present invention, the particles (B) used are agitated at the maximum peripheral speed V represented by the formula (I) with respect to the average diameter D.

100 ≦ V / D ≦ 4000 (I) [wherein D represents the average diameter (mm) of the particles (B), and V represents the maximum peripheral speed (m / sec) of stirring. When the V / D is less than 100, the dispersibility of the solid particles (A) is insufficient, and when the V / D is more than 4000, the effect of improving the dispersibility of the particles is no longer small, while the stirring blade It is not preferable because it causes abrasion and causes problems such as contamination of the slurry. A preferable V / D is 150 <V / D ≦ 3100, more preferably 200 <V / D ≦ 2200.

The time required for dispersion is arbitrary depending on the characteristics of the solid particles (A) to be dispersed and the dispersion conditions, but is usually 20 minutes to 20 hours, preferably 30 minutes to 10 hours.

When the dispersion time is shorter than 20 minutes, the dispersibility is insufficient and a large number of aggregated particles remain.On the other hand, when the dispersion time is longer than 20 hours, the effect of improving the dispersibility is no longer observed, and on the contrary, the dispersion particles are This is not preferable because problems such as aggregation and pulverization occur. After the dispersion treatment, the particles (B) are separated from the slurry by a method such as filtration or sedimentation separation.

After the separation, the slurry can be further filtered as necessary to remove coarse primary particles.

〔The invention's effect〕

By the method of the present invention, target particles can be finely dispersed to almost primary particles, and a uniformly dispersed slurry containing no coarse aggregated particles can be obtained.

When the slurry obtained by the method of the present invention is added to the polyester production step, a polyester having no agglomerated particles and uniformly dispersed particles can be produced, and a surface-smooth fiber, film,
A molded product such as an injection molded product can be obtained.

Furthermore, since there are no agglomerated particles and the particles are dispersed uniformly, there are few troubles during molding such as yarn breakage and increase in the filtration pressure of the polymer filter, and the resulting molded products also have defects such as coarse protrusions and fisheyes. Is extremely small.

Hereinafter, the present invention will be described in more detail with reference to examples.

The parts in the examples represent parts by weight. The particle size of the slurry is a value measured using a centrifugal sedimentation type particle sizer CP-2 manufactured by Shimadzu Corporation.

Further, coarse particles were evaluated by observing a grind gauge and a slurry made by Yoshimitsu Seiki under a microscope.

Example 1 40 parts of titanium oxide having an average primary particle diameter of 0.25 μm measured with an electron microscope, 200 parts of ethylene glycol, and 0.2 parts of phosphoric acid.
6 parts and 0.26 parts of triethylamine are mixed, 300 volume parts of glass beads having an average particle diameter of 0.09 mm (glass beads / titanium oxide particle size ratio = 360) are added to this, and 2 at 3000 rpm using a cross blade with a blade diameter of 16 cm ^Φ. Stir for hours. (V / D = 279.3) After dispersion, filter with 400 mesh gold steel to remove the glass beads and separate the titanium oxide slurry by 2 μm.
It was filtered with an m filter. The average diameter of titanium oxide in the obtained slurry was 0.26 μm, and the coarse particles measured by a grind gauge were 1 μm or less. Further, the slurry was sandwiched between cover glasses and evaluated by a microscope. As a result, aggregated particles of 1 μm or more were not observed, and a good dispersion state was shown.

Comparative Example 1 Dispersion was carried out in exactly the same manner as in Example 1 except that glass beads of 1.5 mm were used instead of glass beads of 0.09 mm in Example 1,
Adjusted the slurry. Glass beads / titanium oxide particle size ratio =
6000 and V / D = 16.8.

The average particle size of the obtained slurry was 0.30 μm, and the number of coarse particles measured with a grind gauge was 3 μm. Also, when observing the dispersed state of particles with a microscope,
There were many agglomerated particles of ˜3 μm. Further, the obtained slurry was colored in grayish white.

Example 2, Comparative Example 2 100 parts of dimethyl terephthalate and 60 parts of ethylene glycol
And 0.04 parts of manganese acetate were added, and transesterification was carried out at 150 to 240 ° C. for 4 hours while removing methanol.

Then add 0.02 parts phosphoric acid and 0.03 parts antimony trioxide,
1m after adding 6 parts of ethylene glycol slurry
Polycondensation reaction was performed for 3 hours at a high vacuum of mHg or less to obtain polyethylene terephthalate containing 1.0% by weight of titanium oxide.

A film obtained by extruding this polymer into a sheet with an extruder and stretching it in the width and length by 3 times each has a good grain with no coarse protrusion of 30.75 μm or more as measured by a microwave interferometer. It showed the dispersibility of On the other hand, when the slurry obtained in Comparative Example 1 was similarly used for film formation and measured, a large number of coarse protrusions of 1 μm or more were observed and the dispersibility of the particles was poor.

Comparative Example 3 Dispersion was performed in the same manner as in Example 3 except that the number of revolutions of the cross blade was changed from 3000 rpm to 1000 rpm in Example 1, and the slurry was adjusted. V / D is 93.1.

The obtained slurry had an average particle size of 0.4 μm, and coarse particles measured with a grind gauge were 4 μm. Further, when observing the dispersed state of the particles with a microscope, a large number of aggregated particles of 2 to 4 μm were present.

Example 3 15 parts of synthetic calcium carbonate having an average particle size of 0.50 μm measured with an electron microscope, 100 parts of ethylene glycol, 1 part of phosphoric acid and 1 part of triethylamine were mixed, and glass beads having an average particle size of 0.05 mm (glass Add beads / calcium carbonate particle size ratio = 100) 1.2 times the volume equivalent to 100 parts of ethylene glycol and use a cross blade with a diameter of 30 cm ^Φ to
Stir at 000 rpm for 3 hours. (V / D = 942) 5 after dispersion
The calcium carbonate slurry obtained by removing the glass beads by filtering with a 00 mesh gold steel was further filtered through a 3 μm filter. The average particle size of calcium carbonate in the obtained slurry was 0.52 μm, and the coarse particles measured by a grind gauge were 2 μm or less. Further, the slurry was pinched on the cover glass and evaluated by a microscope. As a result, no aggregated particles of 2 μm or more were observed. Further, the color tone of the slurry was white.

Furthermore, in place of the titanium oxide slurry in Example 2,
Polymerization and film formation were performed in exactly the same manner as in Example 2 except that the synthetic calcium carbonate slurry was added such that the synthetic calcium carbonate was 0.5% with respect to the polymer. A large number of uniform protrusions were formed on the film surface, and no coarse protrusions of 1 μm or more were observed, indicating that the film had good particle dispersibility.

Example 4 20 parts of kaolinite having an average primary particle size of 1.20 μm measured with an electron microscope and 100 parts of ethylene glycol were mixed, and glass beads having an average particle size of 0.08 mm (glass beads / kaolinite particle size ratio = 66.7) were mixed therein. ) 1.5 volume doubling example of capacity corresponding to 100 parts of ethylene glycol and stirred for 2 hours at 3500rpm using the cross blade of the blade diameter 50 cm ^[Phi. (V / D = 1145)
After the dispersion was completed, the glass beads were removed by filtering with a 200 mesh metal rope, and the average particle size of kaolinite in the slurry obtained by separation was 1.24 μm, which was measured by a grind gauge.
In the evaluation by a microscope, no aggregated particles having a size of 3 μm or more were observed, showing a good dispersion state.

Example 5 30 parts of barium sulfate having an average primary particle diameter of 0.21 μm measured by an electron microscope and 100 parts of water were mixed, and an average particle diameter of 0.0
3 mm glass beads (glass beads / barium sulfate particle size ratio of 143) were added 0.8 times the volume corresponding to 100 parts of water, and the mixture was stirred at 3000 rpm for 1 hour and 20 minutes using a perforated disc blade with a blade diameter of 50 cm. (V / D = 2618) After the dispersion was completed, the glass beads were removed and separated by a 15 μm metal sintered filter, and barium sulfate slurry obtained was further filtered through a 3 μm filter. The average particle size of barium sulfate in the obtained slurry is 0.22 μm.
According to the measurement by the grind gauge and the evaluation by the microscope, there were few agglomerated particles of 1 μm or more and fine particles of 0.05 μm or less, and a good dispersion state was shown. Furthermore, the color tone of the slurry showed a good white color.

Comparative Example 4 Dispersion was performed in the same manner as in Example 3 except that glass beads of 1.5 mm were used instead of the glass beads of 0.05 mm in Example 3, and the slurry was adjusted. Glass beads / calcium carbonate ratio = 3000, V / D = 31.4.

The average particle size of calcium carbonate in the obtained slurry was 0.68.
The size of the coarse particles measured with a grind gauge was 5 μm. Also, when observing the dispersed state of particles with a microscope, it is 1
Many agglomerated particles of ˜3 μm and ultrafine particles of 0.1 μm or less were scattered, and the particle sizes were uneven. Further, the obtained slurry was colored in grayish white.

Comparative Example 5 Dispersion was performed in the same manner as in Example 4 except that the number of revolutions of the disk blade with holes was changed from 3000 rpm to 5000 rpm in Example 5, and the slurry was adjusted. V / D = 4363.

The average particle size of the obtained slurry was 0.18 μm. When the dispersed state of the particles was observed with a microscope, many pulverized fine particles of 0.05 μm or less were scattered and the particle diameters were not uniform.

Further, the obtained slurry was colored in grayish white.

Claims (1)

[Claims] 1. Dispersing particles in a liquid to prepare a particle slurry, which has an average primary particle diameter of 10 to 5000 times the average primary particle diameter of dispersed particles (A), and the average particle diameter is 1.0m
A method for preparing a particle slurry, which comprises stirring particles (B) having a size of m or less at a stirring speed represented by the following formula (I), and thereafter separating particles (B) from a slurry of particles (A). 100 ≦ V / D ≦ 4000 (I) [wherein V represents the maximum peripheral velocity (m / sec) of stirring, and D represents the average diameter (mm) of the particles (B). ]