JPS61118460A - Production of pigment composition - Google Patents

Abstract

PURPOSE:To obtain a pigment composition for lacquer, etc., economically, without lowering the pigment characteristics such as light-resistance, heat-resistance, etc., nor causing the clouding of the color, by dissolving two or more kinds of organic pigments in an aprotic polar organic solvent in the presence of a caustic alkali. CONSTITUTION:The objective pigment composition can be produced by dissolving (A) two or more kinds of soluble organic pigments (e.g. composed of quinacridone-, azo- or thioindigo-based pigments) in (B) an aprotic polar organic solvent (e.g. dimethyl sulfoxide) in the presence of (C) a caustic alkali (e.g. sodium hydroxide, potassium hydroxide, etc.), neutralizing and reprecipitating the solute with (D) an acid (e.g. sulfuric acid, hydrochloric acid, organic acid, etc.), and subjecting the precipitate to filtration, washing, etc.

Description

[Detailed description of the invention] Ru.

In the case of pigments of the same type that are similar in chemical structure, for example, quinacridone and its derivatives, it is known that they can be co-precipitated and made into a solid solution by dissolving them in concentrated sulfuric acid and introducing them into the draining process (Japanese Patent Publication No. 1973-1999). 28014).

Furthermore, a method for producing a pigment alloy by thoroughly subjecting a mixture of at least two types of pigments of different genera to wet milling is also disclosed (Japanese Patent Laid-Open No. 57-50765).

In the former case, the color gamut is limited because it is possible only between pigments of the same type that are similar in chemical structure.
There are limits to how K can respond to market needs.

In addition, in the latter case, from the point of view of forming a pigment alloy with different pigments, there is no restriction that the color gamut is limited;
In the end, it is impossible to go beyond mechanical blending,
It should be considered that transparency, dispersibility, etc. were improved because each pigment was ground into smaller pieces. Therefore, in order to expect an effect, a strong grinding force and the aid of a grinding aid will be necessary.

This means that it is not possible to prevent the ground media from being mixed into the product.
It is almost impossible to remove by post-processing.

Therefore, the purity of the product eventually decreases, and the color saturation, brightness, etc. are adversely affected. This thing is paint.

InΦ, when used in the field of resin coloring, it appears as a dull color or lack of transparency. Further, as major drawbacks of the mechanical trituration method, non-uniformity of particle size and reduction in light resistance and heat resistance due to crystal crushing cannot be avoided.

In fact, in JP-A-57-50765, referring to the X-Ray diffraction results of the pigment alloy produced, there is even an expression that it is similar to an amorphous material, and it has more favorable physical properties and application performance, especially more How much more effort was required to bring out such characteristics as brighter and more uniform hues, higher color strength and transparency and higher gloss and better dispersion in plastics and lacquers, and how This suggests that other important properties of the pigment are impaired.

The present inventors have studied and investigated a method for producing a pigment composition that improves these defects without using mechanical grinding, and have found
It was confirmed that many organic pigments dissolve in the presence of caustic alkali, and a new method for producing pigment compositions by chemical pigmentation was discovered.

That is, the present invention provides a method for producing a pigment composition by dissolving two or more types of organic pigments soluble in an aprotic polar organic solvent in the presence of a caustic alkali, and neutralizing and reprecipitating with an acid. .

In manufacturing such a pigment composition, the combination of raw pigments forms and dissolves caustic alkali and salt in the solvent, but a solvent with such ability is used. Examples include dimethyl sulfoxide, dimethylimidazolidinone, N-methylpyrrolidone, etc., but dimethyl sulfoxide is better in terms of solubility, solvent recovery, etc. It is difficult for these solvents to completely dissolve the pigment in a completely non-aqueous state, but when a small amount of water is mixed in, the solubility increases and the dissolution becomes easier. However, the moisture content is 20
When the temperature exceeds 1, the solubility decreases again and dissolution becomes difficult.

Usually, a water content of about 10 to 15 cm allows for most effective dissolution.

As the caustic alkali used in this dissolution operation, caustic soda and caustic potash are preferably used.

The obtained pigment mixed solution is converted into a pigment by setting neutralization and reprecipitation conditions according to the intended use of the pigment. At this time, as acids used for neutralization, inorganic acids such as sulfuric acid and hydrochloric acid and various organic acids can be used, but in consideration of the performance of the resulting pigment composition, it is preferable to use sulfuric acid, hydrochloric acid, and acetic acid.

Regarding the neutralization and reprecipitation conditions, since the temperature during neutralization and reprecipitation greatly affects the particle size, it is necessary to carry out neutralization and reprecipitation while controlling the temperature to obtain the desired particle size. be. Usually at 80~90℃ (L4~(L5 Miku e7
, 1lL3-14 microy at 70-80℃, 40-60
12-cL5 micron at °C, (L1-l
Since L2 micron changes from 1 LO5 to α1 micron at 0 to 10''C, the desired particle size can be selected within this range.

The precipitate slurry obtained by neutralization and reprecipitation is filtered and washed by conventional means and subjected to surface treatment, etc., if necessary, to obtain a pigment composition that is clear and has excellent heat and light resistance.

To obtain the pigment composition of the present invention, dimethyl sulfoxide, dimethylimidasilidinone, N
- It must be an organic pigment that can be dissolved in an aprotic polar organic solvent such as methylpyrrolidone and neutralized and reprecipitated with an acid; examples of these pigments include quinacridone, azo, and thioindigo pigments. I can do it.

According to the production method of the present invention, the pigment composition between different pigments is
It can be realized economically without deteriorating important properties of pigments such as light resistance and heat resistance, and without causing color turbidity.

There are no particular restrictions on the composition range of the pigments to be combined, and it can be realized arbitrarily.

Furthermore, by adjusting the neutralization and reprecipitation conditions, the particle size of the pigment can be arbitrarily controlled within the range of cL05 to (L5 microns), and the particle size is also uniform.

In addition to the above characteristics, a major feature of the present invention is that a pigment composition having a color tone that cannot be obtained by mechanical blending of pigments can be obtained.

Hereinafter, the present invention will be explained in more detail with reference to examples. Hereinafter, "part" means part by weight, and "chi" means percent by weight.

Example 1 24 parts of unsubstituted Nacridone and ON Pig Orang
Weigh out 300 parts of dimethyl sulfoxide containing 566 parts of water and 10 parts of water into a flask, and add 155 parts of caustic potassium with stirring to form a homogeneous slurry.

As stirring continued at room temperature, the system gradually turned blue-purple, changing from a slurry to a deep blue-purple solution.

After continuing stirring for about 1 hour, the mixture was neutralized by slowly adding 50% sulfuric acid while cooling to 0°C. Once the prayer is complete,
After stirring for 1 hour and then aging, dilute with 150 parts of water and pass through a filter. The obtained cake-like material was redispersed and washed with about 16 ml of water and filtered again. This operation was repeated three times and dried for 12 hours in a hot air dryer at 60°C. ~(obtained the desired product with a particle size of 11 microns.

Example 2 Replace CX Pig Orange 56K with C engineering P
Re(L170) was also replaced with dimethyl sulfoxide containing 10% water as the solvent to obtain a reddish-purple object with a particle size of 10% micron.

Example 5 24 parts of 410 dichloroquinacridone and C-P1gOra
Weigh out 50.0 parts of N-methyl 2-pyrrolidone containing 6 parts of Nge 56 and 10 parts of water into a 7 flask and add 10 parts of caustic soda with stirring to form a homogeneous slurry. After continuing Kq stirring at room temperature for about 1 hour,
0"CK While cooling, neutralize with 15% hydrochloric acid.Hereafter, by performing the same operation as in Example 1, 105~
A deep red-orange object with a particle size of 11 microns was obtained.

Example 4 27 parts of unsubstituted Nacridone and C Pig Red 88
Weigh out 500 parts of dimethyl sulfoxide containing 5 and 10 parts of water into a flask, and add 10 parts of caustic soda while stirring. After stirring for about 1 hour to dissolve, the mixture was cooled to 0°C and neutralized with 50 thiacetic acid. Hereinafter, by performing the same operation as in Example 1, 105 to I
A dark reddish-purple object with a particle size of IL1 micron was obtained.

Example 5 27 parts of unsubstituted quinacridone and C-Pig Orange
Weigh out 500 parts of dimethyl sulfoxide containing 365 parts and 10 g of water into a flask, and add 155 parts of caustic potash while stirring. After stirring for about 1 hour to dissolve, heat to 70°C and neutralize with 50% sulfuric acid. Hereinafter, when the same operation as in Example 1 is performed, II.
A red-orange object with a particle size of L2-13 microns was obtained.

Example 6 27 parts of 2.9-dimethylquinacridone and C engineering P electric, -1
N-methyl 2 containing 1753 parts of M and 10 t of water
Weigh out 300 parts of pyrrolidone into a flask, and add 155 parts of caustic potash while stirring.

After stirring for about 1 hour to dissolve, heat to 70 ° C.
Neutralize with ob sulfuric acid. Thereafter, the same operation as in Example 1 was carried out to obtain a purple target product having a particle size of about 1 liter and 5 microns.

Example 7 By repeating the same procedure as in Example 1 except that 24 parts of unsubstituted Nacridone was changed to 15 parts and 6 parts of 0171g Orange S 6 was changed to 15 parts, a dark reddish-purple object having a particle size of about 105 microns was obtained. I got something.

Claims (6)

[Claims] (1) A method for producing a pigment composition, which comprises dissolving two or more soluble organic pigments in an aprotic polar organic solvent in the presence of a caustic alkali, and neutralizing and reprecipitating with an acid. (2) The manufacturing method according to claim (1), in which a quinacridone, azo, or thioindigo pigment is used as the organic pigment. (3) The production method according to claim (2), wherein the quinacridone pigment is linear unsubstituted quinacridone, 2,9-dimethylquinacridone, 3,10- and 4,11-dichloroquinacridone. (4) The manufacturing method according to any one of claims (1) to (3), in which caustic soda or caustic potash is used as the caustic alkali. (5) A statement in any one of claims (1) to (4) in which dimethyl sulfoxide, dimethylimidazolidinone, or N-methyl 2-pyrrolidone is used as the aprotic polar organic solvent. manufacturing method. (6) The manufacturing method according to any one of claims (1) to (5), using sulfuric acid, hydrochloric acid, or an organic acid as the acid.