CS208644B1 - Method of preparation of the stabilized aqueous dispersions of the ftalocyanine pigments - Google Patents

Description

Process for preparing stabilized aqueous dispersions of phthalocyanine pigments

The invention relates to a process for the preparation of stabilized aqueous dispersions of phthalocyanine pigments having properties of true solutions, which are suitable for both spectrophotometric and objective color measurement. These stabilized dispersions can be prepared from raw and pure phthalocyanine pigments and from their commercial application forms regardless of their crystallographic modifications and finishes.

The non-metallic phthalocyanine of the formula ^{C 3} 3216''8 derived therefrom metallic ftalocytaniny c ₂ ^H ig g ^{N Me Me} 3 ^e Μθ ^{Cu »Co» Fe} or ^IR # ^ s and derivatives in which 1 hydrogen atoms replaced by halogen (Cl, Br) are practically insoluble in conventional inorganic and organic liquid solvents. They dissolve well only in concentrated 90 to 100% sulfuric acid, resulting in solutions of a color complementary to that of the original powder pigment. For example, solutions of copper phthalocyanine in sulfuric acid are yellow to yellow-brown depending on the concentration, while the pigment is blue in all its application forms. However, solutions of phthalocyanines in concentrated sulfuric acid are used for spectrophotometric determination of their content. For less pure products, impurities absorbing also at the wavelength used (eg 440 nm) cause positive errors. The preparation of dilute solutions for measurement requires relatively large amounts of pure concentrated sulfuric acid, and continuous work also poses a risk to work. In addition, solutions are obtained

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208 844 are completely different in color from the respective pigments and do not allow a comparison of color values - color tone and purity - in the area corresponding to the actual color of the pigments.

These disadvantages are eliminated and new possibilities of evaluation and monitoring of the coloring of phthalooyanine pigments are made possible by the method of preparation of stabilized aqueous dispersions, which consists in that the solution of pigment in 90 to 100% sulfuric acid at a concentration of 0.5 to 1.0 g / l is slowly added. to 1 to 3% of an aqueous dispersant solution, in particular nonionic, wherein the concentration of the oigment in the prepared dispersion is 0.01 to 0.05 g / l. The dispersions added in the ponsan manner have the same color shade as the original pigments, i.e. they are blue in the case of copper phthalocyanine, are stable, do not sediment even after tens of hours, and are reproducible in color, e.g. Dispersions are optically isotropic and are governed by Lambert-Beer law. They meet the requirements for objective color measurement and for calculating the color difference of the oroti standard. Due to the method of preparation, the original crystallographic modification of the oigment does not affect the properties of the dispersion, so that the color of the dispersion is dependent on the purity of phthalocyanine and the presence of colored impurities.

The following examples are provided to further illustrate the invention.

Example 1

Accurate weighings of a sample of pure copper phthaloyanine of about 0.050 g were dissolved in 100 ml volumetric flasks in about 60 to 70 ml of 95% sulfuric acid. After 30 minutes complete dissolution was achieved and the solutions were made up to 100 ml. After 2 ml of each solution, 15 ml of a 3.3% aqueous solution of non-ionic dispersant and 10 ml of distilled water in 50 ml volumetric flasks were added from the burette to the flasks and cooled to room temperature with water to 50 ml.

After 1 hour, it was measured by spectradispersion in the range of 400 to 700 nm by 10 nm, and the compolementary trichromatic coordinates (x, * y ') characterizing the color of the dispersion were calculated from the absorbance values. They were used to estimate the instantaneous reproducibility for the four narral assays, expressed as the standard deviation s.

. * *

Oigment concentration in dispersion (g / l) x y

0.019 552 0,526 470 0,441 122 0.019 392 0,527 195 0,441 380 0.019 564 0.527 401 0.441 258 0.019 452 0,527 960 0.441 533 rf 0,527 190 0,441 338 $ + 0.000 522 and 0.000 184 in + 0,10% + 0,04 g

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Long-term reproducibility for 5 pairs of parallel measurements measured over 6 months was assessed equally.

Pair nigment concentration x * y * in dispersion (g / 1)

1 0.019 392 0,527 195 0.441 258 0.019 564 0.527 401 0.441 438 2 0.019 576 0,526 246 0,440 333 0.019 553 0,526 425 0.441 344 3 0.019 688 0,527 424 0.438 017. 0.019 796 0,527 914 0.438 082 4 0.019 468 0.525 354 0.439 783 0.019 384 0,526 285 0.439 976 5 0.019 576 0,527 099 0.438 682 0.019 468 0,528 250 0.439 293 and 0,526 959 0.439 821 ³ ± 0.000 501 0.000 383 v + 0,10% + 0.09%

The indicated values show that the short and long term reproducibility of the preparation of the stabilized dispersion is good.

Example 2

Accurate weighings n ^ = 0,04856 g and n? = 0.04832 g of nickel phthalocyanine were dissolved in a 100 ml volumetric flask in 98% sulfuric acid as in Example 1. After addition to the mark, certain volumes of solutions were measured dropwise from both solutions into 50 ml volumetric flasks in which 30 ml of a 1% aqueous solution of non-ionic dispersants. After cooling to 20 ° C, the dispersions were made up to 50 ml with a 1% dispersant solution. Absorbances were measured at 600 nm in 1 cm cuvettes for all dispersions.

From the given values of concentrations and absorbances ⁿ l ⁿ 2

c (g / 1) ^A 600 c (g / 1) ^A 600 0,009 712 0.498 0,009 664 0.490 0.012 625 0,621 0,012 563 0,621 0,014 568 0.715 0,014 496 0,718 0,016 510 0.810 0,016 428 0.810 0,019 424 0,940 0,019 328 O.94Ó

linear regression o = 0.019 * 667 · Αζθθ (1) was calculated

208 844 where c is the concentration of nickel phthalocyanine in g / l

The Agoo '3® absorbance of the dispersion at 600 nm in 1 cm nod.

The dependence is strictly linear with correlation coefficient ř = 0.9996.

Example 3

The batch and 0.099982 g of pure copper phthalocyanine were dissolved in a 100 ml volumetric flask in 100 ml of 100% sulfuric acid and a stabilized aqueous dispersion was prepared in 50 ml of a 1% aqueous solution of non-ionic dispersants as described in Examples 1 and 2. .

Balance b 0.05075 g of chlorinated copper phthalocyanine with an average content of about 9 Cl atoms per molecule was dissolved in a 100 ml volumetric flask over 1 hour in 100% sulfuric acid. The solution was slowly added dropwise from the burette (3 ml) to a mixture of 15 ml of a 3.3 ml aqueous solution of non-ionic dispersants with 15 ml of water and, after cooling to 20 ° C, made up to the mark with water.

The spectra of both dispersions - copper phthalocyanine and chlorinated copper phthaloyanine - in the 400 to 700 nm range at 10 nm were measured and calculated from the absorbances of the complementary trichromatic coordinate x ', yf characterizing the color of the dispersions. Dispersion of copper phthalocyanine is visually blue, in chlorinated oroduct it is blue-green. The color difference is clearly evident from the x, * y coordinate changes. *

Substance c (g / 1) x 'y' phthalocyanine Cu 0.019 39 0.527 195 0.441 380 chlorinated phthalocyanine Cu 0.030 05 0.558 134 0.372 379

Claims (1)

SUBJECT OF THE INVENTION Process for the preparation of stabilized aqueous dispersions of phthaloyanine pigments suitable for spectrophotometric measurements, characterized in that a pigment solution in 90 to 100% sulfuric acid of a concentration of 0.5 to 1.0 g / l is slowly introduced into a 1-3% aqueous dispersant solution, in particular nonionic, wherein the cohesentation of the nigment in the prepared disoere is 0.01 to 0.05 g / l. Price: 2,40 Kčs Printed by Moravian Printing Works, plant 12, Leninova 21, Olomouc