JPH1036697A - Microparticulate isoindoline pigment and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a microparticulate pigment undergoing less agglomeration by which a conventional isoindoline organic pigment is troubled when it is dispersed. SOLUTION: This pigment has a specific surface area of 80-130m<2> /g and surface-coated with a fatty acid with a 4-20 C alkyl chain. This is produced by subjecting a mixture comprising an isoindoline organic pigment, a water-soluble inorganic salt, a 5-20 C fatty acid and a water-soluble solvent to salt milling and removing the water-soluble inorganic salt and the water-soluble solvent from the mixture by washing with water.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a pigment having fine particles and little secondary aggregation.

[0002]

2. Description of the Related Art In general, the degree of dispersion of pigments in paints and inks is increased by increasing the degree of dispersion in a disperser. Ordinary dispersing machines such as sand mills, three rolls and ball mills can disperse pigments to primary particles by increasing the dispersing time by increasing the dispersing time, increasing the amount of filler, or narrowing the clearance. . However, even if it is further dispersed, the transparency and the like do not change. This is because the dispersion process in a normal disperser is mainly composed of secondary particles (primary particles are weakly aggregated)
The primary particles are only broken by breaking the primary particles. In order to further improve the transparency, it is necessary to further reduce the primary particles. In a high-speed sand mill, it is also possible to make the primary particles fine depending on the pigment used. However, it is difficult to make the primary particles fine even by applying a large amount of energy with a general pigment, and if it is desired to obtain desired fine particles, a large amount of energy is required, leading to an increase in cost. Conventionally, as a method of forming primary particles of pigment into fine particles, a method of dissolving a pigment in a strong acid such as concentrated sulfuric acid or polyphosphoric acid and injecting the same into cold water to precipitate fine particles of the pigment is known. The pigment to be used is limited in terms of solubility and stability of the pigment in strong acids. In addition, since the finely divided pigment obtained by this method causes strong secondary agglomeration when dried, a large amount of energy is required in the dispersion process when manufacturing ink, paint, and the like using this pigment. Often.

[0003] As another method, a method is known in which a pigment and a solid resin are heated and kneaded with a two-roll mill or a Banbury mixer while heating. However, since pigments generally grow at high temperatures, this method ends when the mechanical crushing force and crystal growth reach an equilibrium state, and there is a limit to the fineness of the pigment. In addition, as a method of finely dividing the primary particles of the pigment, a mixture of the pigment and a water-soluble inorganic salt such as sodium chloride or sodium sulfate is moistened with a small amount of a water-soluble solvent such as polyethylene glycol, and then ground with a strong force such as a kneader. ,
There is a method in which a water-soluble inorganic salt and a water-soluble solvent are washed away with water and dried to obtain a fine pigment. Even in this method, when dried, strong secondary aggregation occurs, and dispersion is often difficult.

Japanese Patent Application Laid-Open No. 58469/1985 discloses that a mixture of two types of isoindoline compounds is dry-pulverized into ultra-fine particles and then heated in an organic liquid or the like to obtain excellent color density and transparency. A method for producing a new yellow-red pigment suitable for coloring a synthetic resin, a printing ink or the like is described. In this method, fine particles obtained by dry pulverization are heated with a solvent (DMF), thereby compensating for the disadvantage that fine particles cause strong secondary agglomeration during drying, resulting in poor dispersion. JP-A-60-69165 discloses a method for producing an easily dispersible isoindoline pigment preparation by suspending a specific isoindoline pigment in an aqueous medium and adding a natural or modified natural resin to the offset printing varnish or varnish. Although a surface treatment method for isoindoline that can be easily dispersed in a thermoplastic resin is described, it is possible to easily disperse but not to make fine particles.

[0005]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems of the conventional method, and relates to a method for producing a pigment which is fine, uniform and less agglomerated (fine particle pigment).

[0006]

According to the present invention, the specific surface area is 8
0 to 130 m ² / g, and the carbon number of the aliphatic chain is 4 to ²
The present invention relates to an isoindoline-based pigment whose surface is coated with 0 fatty acid. Further, the present invention provides an aliphatic chain having 16 to 1 carbon atoms.
And 8.

Further, the present invention provides a method for producing a mixture of an isoindoline-based organic pigment, a water-soluble inorganic salt, a fatty acid having 5 to 20 carbon atoms and a water-soluble solvent, which is then subjected to salt milling. The present invention relates to a method for producing a particulate isoindoline-based pigment, wherein the water-soluble solvent is removed by washing with water. Further, the present invention provides a salt milling solution containing a water-soluble inorganic salt in a weight ratio of 2 to a water-soluble solvent.
The present invention relates to a method for producing the above-mentioned fine particle isoindoline pigment used up to 20 times.

[0008]

More specifically, the salt milling method is described in more detail by adding a small amount of a water-soluble solvent as a wetting agent to a mixture of an organic pigment, a fatty acid having 5 or more carbon atoms, and a water-soluble inorganic salt. After kneading strongly with
It is poured into water to dissolve a water-soluble inorganic salt and a water-soluble solvent to form a slurry. Next, the slurry is repeatedly filtered and washed with water to remove the inorganic salt and the solvent. The wet cake containing water is dried at 80 ° C. for 18 hours to obtain a dry pigment.

The pigment used in the present invention is an isoindoline type C.I. I. Pig. Yellow 139, 18
5, C.I. I. Pig. Orange 66, 69, C.I.
I. Pig. Red 260 and the like.

The fatty acid used in the present invention is a linear or branched carboxylic acid having a saturated or unsaturated aliphatic hydrocarbon chain having 4 to 20, preferably 16 to 18, carbon atoms. The group may have one or more groups in the molecule. Specific examples of fatty acids include caproic acid, caprylic acid, capric acid, myristic acid, lauric acid, palmitic acid, stearic acid, oleic acid, linoleic acid, linolenic acid, and the like. The amount of the fatty acid added during salt milling is 0.5 to 20% by weight, more preferably 1 to 5% by weight, based on the pigment. If the amount is small, the effect is not sufficient and secondary agglomeration occurs, making dispersion difficult. If the amount is large, the coloring power is reduced.

The water-soluble inorganic salt used in the present invention includes sodium chloride, potassium chloride, sodium sulfate and the like. The water-soluble solvent used in the present invention is not particularly limited as long as it is water-soluble. However, a solvent having a high boiling point is preferable from the viewpoint of safety because the temperature rises during salt milling and the solvent is easily evaporated. . The amount of the water-soluble solvent is 2 to 20 times the weight of the water-soluble solvent with respect to the water-soluble solvent, since the water-soluble solvent is added for the binder and the effect of preventing crystallization. More preferably, it is 3 to 10 times.

For example, 2- (methoxymethoxy) ethanol, 2-butoxyethanol, 2- (isopentyloxy) ethanol, 2- (hexyloxy) ethanol, diethylene glycol, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether , Triethylene glycol, triethylene glycol monomethyl ether, liquid polyethylene glycol, 1-methoxy-2-propanol, 1-ethoxy-2-propanol, 1-ethoxy-2-propanol, dipropylene glycol, dipropylene glycol monomethyl ether, diethylene glycol Propylene glycol monoethyl ether, low molecular weight polypropylene glycol and the like are used.

In addition to the above compounds, additives such as a dispersant and a plasticizer may be used in combination during salt milling, or two or more pigments may be mixed and treated. By this method, a treated pigment containing a finely divided fatty acid is obtained. By using the treated pigment, paints, inks, resist inks for color filters, etc., with significantly improved transparency can be produced. When this treated pigment is used for a pigment dispersion type ink jet recording liquid, a transparent recording liquid having excellent ejection stability can be produced.

The specific surface area of the fine particle pigment can be measured by multi-sorb 12 (manufactured by Yuasa Ionics) which is a BET method (gas adsorption method) after washing the fatty acid adsorbed on the fine particle pigment with a solvent.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on embodiments. In the examples, "parts" indicates parts by weight. [Example 1] Paliotor Yellow D # 1819 (BA
Made by SF C.I. I. Pig. Yellow 139): 2
50 parts, sodium chloride: 2500 parts, oleic acid: 1
0 parts and 200 parts of diethylene glycol were charged into a 1 gallon stainless steel kneader and kneaded for 3 hours. Next, the mixture was poured into 2.5 liters of warm water, heated to about 80 ° C., and stirred. After stirring for about 1 hour to form a slurry, filtration and washing were repeated five times to remove sodium chloride and the solvent, thereby obtaining a wet cake pigment. This was dried in a dryer at 90 ° C. for 18 hours to evaporate water,
A dried pigment (treated pigment) was obtained. When the specific surface area of this treated pigment was measured, it was 100 m ² / g.
From 0 m ² / g, it was confirmed that the fine particle pigment was produced.

Comparative Example 1 Paliotor Yellow D # 1
819 (CI Pig. Yellow manufactured by BASF)
139): 250 parts, sodium chloride: 2500 parts, and 200 parts of diethylene glycol were charged into a 1 gallon stainless steel kneader and kneaded for 3 hours. Next, the mixture was poured into 2.5 liters of warm water, heated to about 80 ° C., and stirred. After stirring for about 1 hour to make a slurry,
Filtration and water washing were repeated five times to remove sodium chloride and the solvent to obtain a wet cake pigment. This was dried in a drier at 90 ° C. for 18 hours to evaporate the water and obtain a dried pigment. When the specific surface area of this pigment was measured, it was 95 m
² / g.

Next, a paint test was conducted on the above pigment. (Dispersion prescription) Pigment 6 parts Phthalkid 133-60 (alkyd resin) 20 parts Xylene 10 parts Dispersion media 3 mm steel ball 300 g Dispersion time Paint conditioner 60 minutes (Additional prescription) Phthalkid 133-60 (alkyd resin) 36 parts Melan 20 (melamine) Resin) 28 parts A paint test was conducted on the pigments of Example 1 and Comparative Example 1 to obtain a table.
1 Since the pigment of Example 1 had little coagulation, the dispersion proceeded, and the gloss, density, and transparency were improved.

TABLE 1 Viscosity (cps) I. Value Gloss Density Transparency 6/60 rpm (60 °) 例 Example 1 150 / 148 1.01 80 1.2 large 比較 Comparative Example 1 140/135 1.04 65 0.8 Small ──────────────────────────────────

Example 2 Paliotor Yellow D # 1
155 (CI Pig. Yellow manufactured by BASF)
185): 250 parts, sodium chloride: 2500 parts, linoleic acid: 20 parts and diethylene glycol 200 parts were charged into a stainless steel 1 gallon kneader and kneaded for 3 hours. Next, the mixture was poured into 2.5 liters of warm water, heated to about 80 ° C., and stirred. After stirring for about 1 hour to form a slurry, filtration and washing with water were repeated 5 times to remove sodium chloride and the solvent to obtain a wet cake pigment. This was dried in a drier at 90 ° C. for 18 hours to evaporate the water to obtain a dried pigment (treated pigment). When the specific surface area of this treated pigment was measured, it was 105 m ² / g,
The fact that the untreated pigment was 38 m ² / g confirmed that a fine particle pigment was produced.

Example 3 Irgazine Orange 3G
L (manufactured by CGY, CI Pig. Orange 66):
250 parts, sodium chloride: 2,000 parts, stearic acid: 15 parts and diethylene glycol 200 parts were charged into a stainless steel 1 gallon kneader and kneaded for 3 hours. Next, the mixture was poured into 2.5 liters of warm water,
The mixture was heated to 0 ° C. and stirred. After stirring for about 1 hour to form a slurry, filtration and washing with water were repeated 5 times to remove sodium chloride and the solvent to obtain a wet cake pigment. This was dried in a drier at 90 ° C. for 18 hours to evaporate the water to obtain a dried pigment (treated pigment). When the specific surface area of the treated pigment was measured, it was 108 m ² / g, and the untreated pigment was 35 m ² / g. Thus, it was confirmed that a fine particle pigment was produced.

Example 4 Pariogen Red L35
85 HD (CI Pig. Red 2 manufactured by BASF)
60): 250 parts, sodium chloride: 2500 parts, palmitic acid: 25 parts and diethylene glycol 250 parts were charged into a stainless steel 1 gallon kneader and kneaded for 3 hours. Next, the mixture was poured into 2.5 liters of warm water, heated to about 80 ° C., and stirred. After stirring for about 1 hour to form a slurry, filtration and washing with water were repeated 5 times to remove sodium chloride and the solvent to obtain a wet cake pigment. This was dried in a drier at 90 ° C. for 18 hours to evaporate the water to obtain a dried pigment (treated pigment). When the specific surface area of the treated pigment was measured, it was 120 m ² / g.
The fact that the untreated pigment was 43 m ² / g confirmed that a fine particle pigment was produced.

According to the present invention, fine particles having a carbon number of 5 obtained by a process requiring a great amount of time and energy by a usual dispersing machine such as a sand mill, a three-roll mill and a ball mill are obtained.
By containing the above fatty acid at the time of salt milling, it was possible to produce it inexpensively and in a short time.

Claims (4)

[Claims] 1. A fine-particle isoindoline pigment having a specific surface area of 80 to 130 m ² / g and a surface coated with a fatty acid having an aliphatic chain having 4 to 20 carbon atoms. 2. The isoindoline pigment according to claim 1, wherein the aliphatic chain has 16 to 18 carbon atoms. 3. After salt-milling a mixture comprising an isoindoline-based organic pigment, a water-soluble inorganic salt, a fatty acid having 5 to 20 carbon atoms and a water-soluble solvent, the water-soluble inorganic salt, and the water-soluble inorganic salt are mixed. A method for producing a finely divided isoindoline-based pigment, wherein the solvent is removed by washing with water. 4. The salt milling uses a water-soluble inorganic salt in a weight ratio of 2 to 20 times the water-soluble solvent.
A method for producing the fine particle isoindoline pigment according to the above.