JPH0696679B2 - Pigmentation of organic pigments - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for pigmenting an organic pigment.

Specifically, in the presence of caustic alkali and water in an aprotic polar solvent, a nonionic surfactant is co-dissolved with an organic pigment, and this is neutralized and reprecipitated with an acid for purification and micronization, and dispersion at the same time. The present invention relates to a pigmenting method for an organic pigment, which is characterized by imparting properties such as stability and dispersion stability.

[Conventional technology]

As a method for modifying an organic pigment using a surfactant, there have been many proposals in the past, but any of them has a process of refining and refining a crude pigment in advance by means such as pulverization or dissolution / reprecipitation. After that, a contact operation with a surfactant is performed to improve the pigment characteristics. That is, since the operation for refining and refining and the operation for modifying the pigment characteristics are performed in two steps, even the pigment particles once refined have already formed aggregates at the time of contact operation with the surfactant. , After all,
In this method, it becomes impossible to bring the surfactant into contact with the primary particles, and the effect of modifying the obtained pigment is not sufficient. Further, the whole process is long and complicated, and it takes a long time, so that it is not an advantageous method from the viewpoints of economy and workability.

[Problems to be solved by the invention]

INDUSTRIAL APPLICABILITY The present invention provides effective pigment modification by performing finer and refinement of a crude pigment and contact treatment of a primary particle with a surfactant in a single step at the same time, and makes the pigment into a simpler step. It provides the law.

[Means for solving problems]

That is, the present invention relates to (a) quinacridone pigment, (b)
A quinacridone pigment and an azo pigment or (c) a quinacridone pigment and a thioindigo pigment, together with a nonionic surfactant selected from the group consisting of polyoxyethylene alkyl ethers and polyoxyethylene alkylphenol ethers, and caustic alkali and water. Dissolved in an aprotic polar solvent in the presence, neutralized and reprecipitated with an acid, then a method for pigmenting an organic pigment, characterized by adding a heteropolyacid or tannic acid, and refining, purification and At the same time, pigment performance such as dispersibility and dispersion stability can be imparted.

The present invention will be described in more detail.

The quinacridone-based pigment used in the present invention is premised to form a salt with a caustic alkali and dissolve in an aprotic polar solvent. Examples thereof include quinacridone, 2,9-dimethylquinacridone, 3,10 or 4,11-dichloroquinacridone. An azo pigment or a thioindigo pigment may be used in combination with these quinacridone pigments.

As the aprotic polar solvent used in the present invention, dimethylsulfoxide, dimethylimidazolidinone, N-
Methyl-2-pyrrolidone and the like are available, but dimethyl sulfoxide is preferable in terms of solubility, solvent recovery, and the like. It is difficult for these solvents to completely dissolve the pigment in the completely non-aqueous state, but by mixing a little water, the solubility is increased and the complete dissolution is facilitated. However, if the water content exceeds 20%, the solubility will decrease again and the solution will not be completely dissolved. Usually, the most effective condition is about 10 to 15% water content. This is because caustic has poor solubility in these solvents in the completely non-aqueous state,
This is because salt formation with the pigment is hindered. The caustic alkali used in this dissolving operation is preferably potassium hydroxide or sodium hydroxide.

In the present invention, the nonionic surfactants that provide the beneficial effects are soluble in the polar solvent system, such as dimethylsulfoxide containing caustic and water as described above, so that they are soluble in the system and, after neutralization with acid, Those having an insoluble or poorly soluble property are suitable for the solvent system.

Examples of nonionic surfactants satisfying such conditions include polyoxyethylene alkyl ethers such as polyoxyethylene lauryl ether, polyoxyethylene cetyl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, and polyoxyethylene oleyl ether. Ethylene alkylphenol ethers such as polyoxyethylene octylphenol ether,
Examples include polyoxyethylene nonylphenol ether, especially HLB (Hydrophile-Lipophile Balance) 15-20
It is desirable that it has a high hydrophilicity. One or two of these
More than one species can be used. These nonionic surfactants effectively act to improve the fineness, dispersibility, dispersion stability, fluidity, transparency and tinting strength of the pigment. In addition, the viscosity of the slurry at the time of neutralization and reprecipitation is reduced, stirring is facilitated, and the reaction system is made uniform. The amount of these nonionic surfactants used is 0.5 to 3 with respect to the crude organic pigment used.
0% by weight, preferably 2-15% by weight is more effective.

The solution in which the pigment and the nonionic surfactant are dissolved is then subjected to neutralization and reprecipitation with an acid. As the acid used for neutralization, inorganic acids such as sulfuric acid and hydrochloric acid and various organic acids can be used, but sulfuric acid, hydrochloric acid and acetic acid are preferably used in consideration of the performance of the resulting organic pigment.

As the conditions for neutralization reprecipitation, it is necessary to carry out the neutralization reprecipitation while controlling the temperature at the time of neutralization reprecipitation to a temperature suitable for obtaining the target particle size because the temperature at the time of neutralization reprecipitation greatly affects Is.

Nonionic surface activity is obtained by adding an aqueous solution of heteropolyacid or tannic acid to the precipitate slurry obtained by neutralization reprecipitation, or gradually adding a precipitate slurry of pigment to the aqueous solution of heteropolyacid or tannic acid. The agent is deposited as a water-insoluble or sparingly water-soluble substance.

The heteropolyacid is selected from phosphotungstic acid, phosphomolybdic acid, silicotungstic acid and silicomolybdic acid. When tannic acid is used, the effect of modifying fluidity is particularly great. The reaction between the nonionic surfactant and the heteropoly acid or tannic acid is not always stoichiometric, and the addition amount of the heteropoly acid or tannic acid is preferably 1 to 5 times by weight with respect to the used nonionic surfactant, Particularly, 2 to 4 times by weight produces more preferable results.

The pigment slurry obtained by the above operation is then subjected to repeated washing with water and repeated drying by ordinary means to be recovered as an organic pigment excellent in fine dispersibility and dispersion stability.

〔The invention's effect〕

As is clear from the above description, according to the pigmenting method of the present invention, it is possible to effectively improve the pigment performance such as dispersibility, dispersion stability, transparency, and tinting strength at the same time as refining and refining. Since it is possible and the process is simple, it is an economically and workably excellent method that is industrially advantageous.

〔Example〕

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

Example 1 30 parts of crude unsubstituted quinacridone was added to 300 parts of dimethyl sulfoxide containing 10% of water, and the mixture was stirred at room temperature to form a homogeneous slurry, and 13.5 parts of potassium hydroxide and 18 parts of water were added. Continue stirring for 1 hour to dissolve the pigment.

Next, polyoxyethylene lauryl ether (HLB16.3)
After adding 1.5 parts and further stirring for 1 hour to dissolve it, 23.6 parts of 50% sulfuric acid is slowly added dropwise over 30 minutes while cooling to 0 ° C. for neutralization and reprecipitation.

The precipitate slurry thus obtained is poured into 500 parts of water in which 4.5 parts of phosphotungstic acid is dissolved, and stirred for 30 minutes. The pigment cake obtained was redispersed in 1,000 parts of water and passed again. This operation was repeated 3 times, and then dried in a warm air dryer at 60 ° C for 16 hours to obtain a fine dark reddish purple pigment. A substituted quinacridone pigment was obtained.

The powder of the unsubstituted quinacridone-based pigment obtained as described above was blended in a melamine alkyd resin varnish for baking coating so that the pigment content was 10%, and ball mill-dispersed to prepare a coating. At this time, the dispersibility of the pigment is good, the pigment particles do not aggregate even after the film formation, and the good dispersion state is maintained. The dispersion state of the pigment crystal particles in the coating film section shown in FIG. It was confirmed by the electron micrograph shown (magnification 20,000). Furthermore, this pigment has excellent transparency and coloring power,
It had a clear hue.

Example 2 The same operation as in Example 1 was carried out except that the same amount of tannic acid was used instead of phosphotungstic acid, to obtain an unsubstituted quinacridone pigment.

The obtained unsubstituted quinacridone pigment was subjected to a paint test in the same manner as in Example 1. As a result, the pigment was excellent in dispersibility, dispersion stability, transparency and tinting strength, and the paint had excellent flowability. Showed sex.

Example 3 An unsubstituted quinacridone pigment was obtained by performing the same operation as in Example 1 except that the same amount of phosphotungstic acid was used instead of phosphotungstic acid.

In the same paint test as in Example 1, this pigment was excellent in dispersibility, dispersion stability, tinting strength and transparency.

Example 4 30 parts of crude unsubstituted quinacridone is added to 300 parts of dimethyl sulfoxide containing 10% of water, and the mixture is stirred at room temperature to obtain a homogeneous slurry. 13.5 parts of potassium hydroxide and 18 parts of water are added and stirring is continued for 1 hour to completely dissolve the pigment. Next, add 1.5 parts of polyoxyethylene nonylphenol ether (HLB18.9), stir for an additional 1 hour to dissolve it, then heat to 50 ° C and add 23.6 parts of 50% sulfuric acid in 30 minutes to re-neutralize. Sink. The resulting precipitate slurry was poured into 500 parts of water in which 4.5 parts of phosphotungstic acid was dissolved,
Stir for a minute and pass.

Thereafter, in the same manner as in Example 1, washing with water and passing were repeated and drying was performed to obtain a deep red fine unsubstituted quinacridone pigment.

When the same paint test as in Example 1 was conducted, this pigment was excellent in dispersibility and dispersion stability, and had a clear hue.

Example 5 The same operation as in Example 4 was carried out except that 4.5 parts of phosphotungstic acid was changed to 3.0 parts of tannic acid to obtain a fine dark red unsubstituted quinacridone pigment.

The same paint test as in Example 1 was conducted to find that the pigment had dispersibility,
It was confirmed that the dispersion stability was excellent and the fluidity was good.

Example 6 Polyoxyethylene lauryl ether was added to the same amount of polyoxyethylene oleyl ether (HLB16), and the neutralization temperature was 0.
The same operation as in Example 2 was carried out except that the temperature was changed to 20 ° C. to obtain a fine red unsubstituted quinacridone pigment.

A paint test was conducted in the same manner as in Example 1, and it was confirmed that the obtained pigment had excellent dispersibility, dispersion stability and fluidity, and had a clear hue.

Example 7 The same amount of polyoxyethylene nonylphenol ether as polyoxyethylene octylphenol ether (HLB1
The same operation as in Example 5 was performed except that the neutralization temperature of 50 ° C. was changed to 5 ° C. in 8) to obtain a fine unsubstituted quinacridone pigment.

When a paint test was conducted in the same manner as in Example 1, this pigment had excellent dispersibility, dispersion stability and fluidity.

Example 8 A fine quinacridone pigment having a strong blue tint was obtained in the same manner as in Example 2 except that the crude unsubstituted quinacridone was replaced with the same amount of crude 2,9-dimethylquinacridone.

As a result of a paint test conducted in the same manner as in Example 1, this pigment was
It was excellent in dispersibility, dispersion stability and fluidity.

Example 9 A fine quinacridone pigment having a strong yellow tint was obtained in the same manner as in Example 2 except that the crude unsubstituted quinacridone was changed to crude 3,10-dichloroquinacridone in the same amount.

As a result of a paint test conducted in the same manner as in Example 1, this pigment was
It was excellent in dispersibility, dispersion stability and fluidity.

Example 10 24 parts crude unsubstituted quinacridone and CI Pigment Red 170
Dimethyl sulfoxide 300 containing 6 parts 10% water
Add to the mixture and stir at room temperature to obtain a homogeneous slurry. Thereafter, the same operation as in Example 1 was carried out to obtain a fine magenta pigment.

According to the same paint test as in Example 1, this pigment showed dispersibility,
It was confirmed that the dispersion stability and transparency were excellent.

Example 11 A fine dark reddish-purple pigment was obtained in the same manner as in Example 10 except that the same amount of CIPigment Orange 170 was used instead of CIPigment Red 170.

The same paint test as in Example 1 was conducted, and it was confirmed that the obtained pigment was excellent in dispersibility, dispersion stability and transparency.

Example 12CIPigment Red 170 was changed to the same amount of CIPigmgnt Red 88, and phosphotungstic acid was changed to the same amount of tannic acid, except that
By the same operation as in Example 10, a fine dark reddish purple pigment was obtained.

A paint test was conducted in the same manner as in Example 1 and it was confirmed that this pigment had excellent dispersibility, dispersion stability and fluidity.

Example 13 21 parts of crude unsubstituted quinacridone and 9 parts of 2,9-dimethylquinacridone are added to 300 parts of dimethyl sulfoxide containing 10% of water and stirred at room temperature to obtain a homogeneous slurry. 10 parts of sodium hydroxide and 15 parts of water are added, and stirring is continued for 1 hour to completely dissolve the pigment. Next, add 1.8 parts of polyoxyethylene nonylphenol ether (HLB18.9), stir for an additional 1 hour to dissolve, then heat to 50 ° C and add 24.5 parts of 50% sulfuric acid dropwise over 30 minutes to neutralize. Re-sink. To the obtained precipitate slurry, 18 parts of 20% phosphotungstic acid aqueous solution is added dropwise, stirred for 30 minutes and then passed.
Thereafter, in the same manner as in Example 1, washing with water, repeated washing, and drying were carried out to obtain a red solid solution pigment.

As a result of a paint test conducted in the same manner as in Example 1, it was confirmed that this pigment had excellent dispersibility and dispersion stability.

Comparative Example The same operation as in Example 1 was carried out except that polyoxyethylene lauryl ether and phosphotungstic acid were removed to obtain a dark reddish purple unsubstituted quinacridone pigment.

A paint test was conducted in the same manner as in Example 1, and the dispersion state of the pigment crystal particles in the obtained coating film section is as shown in FIG. 2 as an electron micrograph (magnification: 20,000 times). It can be seen that aggregates are formed.

[Brief description of drawings]

FIG. 1 is an electron micrograph (magnification: 20,000 times) showing a dispersed state of pigment crystal particles in a coated film section of a pigment obtained in one example of the present invention, and FIG. 2 was obtained in a comparative example. 1 is an electron micrograph (magnification: 20,000 times) showing a dispersed state of pigment crystal particles in a coating film section of a pigment.

Claims (6)

[Claims] 1. A quinacridone pigment, (b) a quinacridone pigment and an azo pigment, or (c) a quinacridone pigment and a thioindigo pigment, which are composed of polyoxyethylene alkyl ethers and polyoxyethylene alkylphenol ethers. Dissolved in an aprotic polar solvent in the presence of a caustic and water together with a nonionic surfactant selected from the group, neutralized and reprecipitated with an acid, and then added a heteropolyacid or tannic acid Method for pigmenting organic pigments. 2. The pigmentation method according to claim 1, wherein the quinacridone pigment is unsubstituted quinacridone, 2,9-dimethylquinacridone, 3,10 or 4,11-dichloroquinacridone. 3. The pigmentation method according to claim 1, wherein the caustic alkali is potassium hydroxide or sodium hydroxide. 4. The aprotic polar solvent is dimethyl sulfoxide, dimethyl imidazolidinone or N-methyl-2-.
The pigmentation method according to any one of claims (1) to (3), which is pyrrolidone. 5. The pigmentation method according to any one of claims (1) to (4), wherein the acid is sulfuric acid, hydrochloric acid or an organic acid. 6. The heteropoly acid is phosphotungstic acid, phosphomolybdic acid or silicotungstic acid, or silicomolybdic acid, as claimed in any one of claims 1 to 5.
Item 6. The pigmentation method according to any one of items.