JPH02132162A - Dispersion of pigment by very small ball of calcined zirconia - Google Patents

Abstract

PURPOSE:To shorten time of pigment dispersion process and to make it uniform by dispersing pigment with very small calcined ball of zirconia having high sphericity. CONSTITUTION:For example, (A) zirconia powder is blended with (B) 6-15wt.% water, stirred at 1,500-2,500rpm of stirring shaft at <=70 deg.C for 25-40 minutes, dried and heat-treated to give calcined ball of zirconia having 200-500mum particle diameter. Pigment is uniformly dispersed into vehicle with a ball mill, peddle mill or sand mill by using the calcined ball of zirconia.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for dispersing pigments into a vehicle using a ball mill, a bevel mill or a sand mill. [Prior Art] In the field of paint manufacturing, one of the central operations is the process of dispersing pigments into a vehicle consisting of a resin, a solvent, etc., and various methods are used to effectively carry out this dispersion process. method should be adopted.

Specifically, ball mills using metal balls or pebble mills using ceramic particles are widely used, and a dispersion process using a high-speed stirring mill called a sand mill is also becoming more widely used.

Each of these consists of a mill and an appropriate amount of balls placed inside it, into which the pigment and vehicle are placed and dispersed by rotation. Conventionally, metal balls, ceramic balls, or glass poles (also called glass beads) have been used as balls. Metal balls, mainly made of steel, are made by mixing small amounts of molybdenum, chromium, Ni-Nokel, manganese, etc. High carbon steel is used, and stainless steel balls are used for special applications.These metal balls come in various sizes, the smallest having an average diameter of 200 to 30 mm.
It has a high sphericity of 0 μm. However, conventional metal holes have the disadvantage that the metal holes are mixed into the vehicle due to wear during use, and cannot be used in products where contamination is a concern. Ceramic balls are also often used, especially those with high hardness and density such as alumina and zirconia. Ceramic balls have high hardness and excellent wear resistance, and have a longer service life than metal balls.
Furthermore, when ceramic balls are used, the shell and mill wall are lined with the same ceramic material, so there is significantly less contamination of the product due to abrasion, which is the case with metal balls. However, compared to metal balls, ceramic balls require a VJ manufacturing process of Wm and are therefore more expensive. Glass pole (or glass beads) is 500μ01~5
Hard glass beads or lead-containing glass beads with a diameter of about mm, and are mainly used in sand mills. However, glass poles have lower hardness than metal balls or ceramic balls, and they also have the disadvantage of being easily crushed during the dispersion process. [Problem to be solved by the invention] In the conventional ball mill, bevel mill or sand mill,
Each ball used has many drawbacks as mentioned above.
There are still points that need to be improved for effective dispersion. The object of the present invention is to use fired zirconia balls, which have high hardness, high toughness, and high density and have a spherical diameter of 500 μm or less, to be effective in dispersing pigments in a vehicle using a ball mill, pebble mill, or sand mill. It provides a method for dispersing pigments. [Means for Solving the Problems] The most dominant factors for the dispersion of the face H in the dispersion process using a ball mill, bevel mill or sand mill are the operative impact force and shear stress applied to the face H. In order to increase the impact force and shear stress, it is important to (1) increase the rotation speed of the mill, (2) increase the density of the ball and reduce its diameter, and (3) select an appropriate ratio of jaw and vehicle. become. Regarding the density and diameter of the balls, in a ball mill, when the balls that are lifted up in the container by the rotation of the container fall and come into contact with each other, the impact force and shear stress on the pigment at the point of contact are ( 4r - Dispersion takes place.The smaller the diameter of the ball, the more impact forces and shear stresses are applied per unit revolution of the mill, and within a given volume the dispersion (number of contact points made for F and In addition, as the diameter of the balls decreases, the gaps between the balls become smaller, which limits the size of paint lumps that can get into those gaps and prevent good dispersion.These impact forces and Shear stress is caused by the gravitational force acting on the ball, and the gravitational force is directly proportional to the density of the ball. Conversely, if the diameter of the ball is large, more impact force and shear stress will be applied than necessary, resulting in wasted power and damage to the ball. therefore,
The higher the density of the ball and the smaller the diameter, the better the dispersion effect. For example, when comparing a fired zirconia ball with a diameter of 250 μm and a hard glass pole with a diameter of 500 μIn, the number of contact points during a unit break is 500 for the 250 μm ball.
This is 8 times the μm ball. Furthermore, if we take into account the difference in the specific gravity of the two strands, the increase in dispersion is thought to be 48 times greater. It is also 24 times more powerful than a lead glass pole with a diameter of 500 Bm. From these things, the diameter is 25
Having confirmed the pigment dispersion effect of zirconia balls with a diameter of around 0 μm, the present inventor conducted research on the production and use of fired zirconia balls, and found that zirconia balls with a diameter of 250 μm
’ of the zirconia fired ball of m! I succeeded in meeting A and would like to apply for a patent.Patent Application No. 32754/1982. Furthermore, we were able to invent an effective method for dispersing pigments using the microparticle fired zirconia balls produced by this method. That is, in the present invention, in a pigment dispersion process using a ball mill, beflu mill, or sand mill, particles with a diameter of 200
This is a method for dispersing a pigment in a vehicle, which is characterized by using fired zirconia balls with a diameter of 500 to 500 μm. Next, we will discuss the manufacturing method of zirconia fired balls. The stirring device used for granulating zirconia balls (green balls, i.e. balls before firing) was manufactured by the Japanese Patent Publication No. 39-21502.
Publication No. 4-19507, Publication No. 4-19507, Publication No. 4-19507
8-4 Publication No. 1284 and Utility Model Publication No. 53-39737
This is the granulation device described in the publication. The granulation method begins with zirconia powder, an organic solvent, and water.
By placing the binder in a granulating device and stirring under certain conditions, the zirconia powder becomes small spheres with high sphericity.
In particular, under the following specific conditions, diameters of 500 μm or less,
Preferably, the particles are microparticles (green balls) with a diameter of around 250 μm. Zirconia ball (green ball) @ 拉拉子原体 powder...Commercially available regular zirconia powder mixed with a small amount of stabilizer. As a stabilizer, for example, the content of yttria and the content of other mixed components are not particularly limited as long as they are within normal levels.

Binder: 6 to 1 per tap water and raw material powder used
5%, preferably 9-11% by weight. Granulation conditions: Stirring shaft rotation speed: 1500-25
0(l rpm preferably 1800-2000 rpm
Temperature: 70°C or less, preferably 45°C or less. Time: 25-40 minutes, preferably 30-35 minutes. The above-mentioned green balls are dried at 60°C for 24 hours and then subjected to high temperature treatment in an electric furnace to produce the final zirconia fired balls. The particles thus obtained have a diameter of 200 to 500μ.
Pigment dispersion using fired zirconia balls having a diameter of approximately 240 to 350 μm is carried out as follows. Mix the pigment, resin liquid, solvent, and additives to make a mill base: AH. This mill base and a fired zirconia ball having approximately the same volume as the mill base were placed in a dispersion mill and heated at a rotational speed of 500 to 200 rpm for 15 minutes to 2 hours.
Allow time to disperse the pigment into the vehicle. A ball mill, pebble mill, or sand mill can be used as a dispersion mill. As pigments, both inorganic blood and DA pigments can be used. The application is not limited to paints, but can be applied to any process that involves dispersing fine powder into a highly viscous liquid, such as ink and dyes. Next, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited thereto. Example 1 A fired zirconia ball was manufactured as follows. In a cylindrical granulation container with an internal volume of 3000 ml, 80 g of zirconia powder mixed with a small amount of a commercially available partial stabilizer (average particle diameter 0.49 μm, specific surface area 7.5 rr?/(1) Imparaffin solvent 2 80 0 ml and 10 g of water was added and granulation was carried out for 30 minutes at a rotation speed of 1800 rpm and a cylinder temperature of 40°C to 45°C.Draw the maximum diameter (L) of the obtained green ball and the maximum diameter (1) perpendicular to it. Fifty samples were measured using an even analyzer (LUZEX500 manufactured by Nireco Co., Ltd.), and the L/I was determined to determine the sphericity.The measurement results are shown in Table 1.Then, the green ball described above was measured. After drying at 60°C for 24 hours, it was placed in an electric furnace and heated through a step-by-step heating process until it reached 1500°C, and then held at 1500°C for an additional 2 hours. The size and pearliness of the fired zirconia balls were measured using the same figurine analyzer.The density was also measured using the Archimedes method.
The measurement results are shown in Tables 2 and 3.

Example 2 A mill base was prepared using titanium oxide as a pigment, an alkinoto resin as a 1M fat, a sorbitan surfactant as a dispersant, and toluene as a solvent. The composition of this mill base is as follows. Titanium oxide 2
0% by weight Alkyd resin 30 1.Dispersant II.Solvent 49.2
Using a 01 Lenotre ball mill, rotation speed 1300r
As a result of dispersion treatment at pm for 1 hour, it was observed that the pigment was completely uniformly dispersed. Example 3 A millbase was prepared using monoarsenic acid as a hematologist, an acrylic resin as a resin, a sorbitan surfactant as a dispersant, and xylene as a solvent. The composition of this Milhose is as follows.

Iron oxide 20% by weight Acrylic resin 30 1 No. dispersant
1 Nono}Container 4QJ7 Using zirconia fired balls with an average particle diameter of 250/lm having the same capacity as the above-mentioned millhose, dispersion was carried out for 1 hour using a 20 liter ball mill with a four-wheel rotation at 1300 rpm. As a result of the treatment, it was observed that the blood was almost completely uniformly dispersed. Example 1 A fired silconia ball was manufactured as follows. In a cylindrical granulation container with an internal volume of 3000 ml, 40 g of zirconia powder (average particle diameter 0.75 μm, specific surface area approximately 7 nf/g) mixed with a small amount of a commercially available partial stabilizer was placed in a normal isoparaffin solvent 2 800 mi and 2 g of yk was added and granulation was carried out for 77 minutes at a rotational speed of 1800 rpm and a cylinder temperature of 40"C to 45°C.Then, the above green balls were dried at 60°C for 24 hours, and then placed in an electric furnace. -i heating process to reach 1500°C, and then held at 1500°C for 2 hours. The average maximum diameter of the obtained zirconia fired balls was 345 μm, L, / The I value was 1.052.Implementation P
A5 Prepare a mill base using carbon as the pigment, alkylide {A resin as the resin, ethylene oxide surfactant as the dispersion milling agent, and toluene as the solvent. The composition of this mill base is as follows. Carphone 23% by weight Alkyd resin 30 9 Dispersant I g Solvent 46tt - Using the same volume of Milhose as described in E, fired zirconia poles with an average particle diameter of 345 μm manufactured in Example 4,
Using a 20 liter ball mill, rotation speed 1500 r
As a result of processing with PM for 1 hour, it was found that the face 1 was completely evenly distributed! I got hit twice.

[Effects of the Invention] It was possible to effectively disperse face [■] in a vehicle using a pono reminole, a pefno reminole, or a sand mill using fired zirconia balls with a particle diameter of 200 to 500 μm, which had a high nacre content that could not be produced conventionally. As a result, the dispersion process time can be shortened or the uniformity of dispersion can be increased. Table 1 Size and sphericity of green balls Sphericity δ Makishi average value <: 8f Table 3 Density of fired balls Immersion Liquid: Purified water measurement temperature = 30°C Vacuum conditions: 2 0sn}Igx l 5 Amount of sample per hour: Approximately log wiping ``L Star-''Density'' work/pressure 10.0134 6.007210.0944 5.9660 9.9650 5.9873 Average value 5.9868

Claims (1)

[Claims] A method for dispersing a pigment in a vehicle, which comprises using fired zirconia balls having a particle diameter of 200 to 500 μm in a pigment dispersion step using a ball mill, pebble mill or sand mill.