CS236324B1 - Method of phthalocyanine pigments treatment - Google Patents

Abstract

Method for treating beta-modified phthalocyanine pigments by grinding copper phthalocyanine in a glycol environment of the general formula H0(CH2CH20)Q Η I where η = 1 to 200, in the presence of sodium chloride at a temperature of 20 to 150 °C, such that after grinding and separation of the pigment by filtration and washing, the pigment is treated with a surfactant of the general formula R CO NH(CH2)m OH I where R is a saturated or unsaturated aliphatic residue with a number of carbon atoms of 12 to 22, m = 2 or 5, dissolved in ethanol or acetic acid, in an amount of 6 to 25% by weight per pigment and the product is isolated. The obtained beta-modified phthalocyanine pigments have maximum color strength, minimum energy during dispersion and suitable flow properties and are applicable especially for gravure printing.

Description

The present invention relates to a process for the treatment of phthalocyanine pigments of the beta modification, particularly suitable for gravure printing.

Developments in the gravure printing technique have led to fast-working printing machines which, on the one hand, allowed work to be rationalized, but on the other hand, the requirements for the quality of the inks, i.e. the individual components and in particular the pigments, were considerably tightened. These requirements relate in particular to color strength and flow parameters, which are difficult to improve for pigment manufacturers at the same time; higher color strength can be achieved by reducing the particle size of the pigment, resulting in an undesirable increase in ink viscosity. By decreasing the particle size, their free surface energy increases and the result is the formation of secondary particles - aggregates that impair the dispersibility of the pigment in printing systems.

These issues are constantly addressed, as evidenced by a number of work on pigment treatment methods (mainly based on the use of adjuvants that reduce particle aggregation and which have an affinity for a given application environment, such as abietic acid compounds). (Brit. Pat. 1 100 103; 900 757; 978 242; Jap. Pat. 51-54620), aliphatic acid salts (US Pat. 2 305-379) aliphatic amines (Jap. Pat. 45 - 209S1; 46 - 32343 ; 48--1821) etc, Phthalocyanine pigments modified by prior art (suitable for less demanding applications, but no longer meet the requirements for pigments for illustrative gravure printing. Such pigments (pigment preparations) must provide maximum color strength, require minimal energy when dispersed, the inks must have a suitable rheology and the prints must have acceptable stability.

- 2 23b 324

These requirements meet the beta modification phthalocyanine pigments prepared according to the invention. Process for their treatment by grinding copper phthalocyanine in the environment of glycols of the general formula

HO (CH ₂ CH ₂ O) _n H where η = 1 20 to 150 after grinding the formula up to 200, in the presence of sodium chloride at a temperature of 0 ° C, according to the invention consists in treating the pigment and separation with a surfactant

R C OH (OH ₂ ) _m OH, where R is a saturated or unsaturated aliphatic residue having a carbon number of 12 to 22, m = 2 or 3, dissolved in ethanol or acetic acid, in an amount of 6 to 25% wt per pigment and the product is isolated.

The process according to the invention starts from a crude copper phthalocyanine beta modification which has been produced by a solvent-free or solvent-based process. Crude phthalocyanine is milled in a malaxer in the presence of glycols and sodium chloride, for example diethylene glycol, triethylene glycol and various polyethylene glycols up to a molecular weight of 6000, and mixtures of polyglycols may be used. The grinding is carried out at a temperature of 20 to 20 ° C.

150 [deg.] C.

Upon completion of grinding, i.e., reaching an average particle size of about 0.05 µm, the malaxer mixture is diluted with water, the pigment is filtered off and washed to remove residual polyglycols and sodium chloride. The filter cake was then suspended in water and the pigment particles is adjusted surfactant RC0HH _{(CH2) n} 0H, which may be for example monoetanolahiid stearic acid · palmitic, oleic etc. · The compound of this invention added to the slurry in an amount of 6 to 25% per pigment and applied from a solution in ethanol or acetic acid.

236 324

The aliphatic carboxylic acid alkanoamide is used to treat the surface of the phthalocyanine pigment particles, suppressing the formation of secondary particles (aggregates) and obtaining hydrophobic properties. After application of the alkanolamide solution, it is preferable to heat the slurry to 80-100 ° C with stirring, after which the treated pigment is isolated very well (filtered). The product is dried in a hazel, spray or vortex dryer.

The treated phthalocyanine pigment prepared by the process of the invention is very well wetted and dispersed in toluene, resulting in maximum utilization of the pigment's coloring ability. The intaglio inks based on this preparation also have favorable flow properties

The process for preparing the treated phthalocyanine pigments of the invention is demonstrated in the following examples.

Example 1

To the malaxer was added 90 g of crude copper phthalocyanine produced by a solvent-free process and 360 g finely. 113 g of diethylphinglycol were then added and dispersion of copper phthalocyanine was carried out at 70 [deg.] C. for 5 hours. Further, 57 g of diethylene glycol was added to the malaxer, and the mixture was heated to 115 ° C. After 2 hours of malaxing, 450 g of water was added to the malaxer. After mixing, the suspension was transferred to a stirrer, stirred with water and filtered. The pigment was washed with water at ca 70 ° C until a negative reaction on the Clve filtrates. 195 g of pigment paste with a dry matter content of 40.0% by weight were obtained. The paste was slurried in 1400 g of water, and a solution of 8 g of monoethanolamide oleic acid in 32 g of glacial acetic acid was added to the suspension with stirring over 15 minutes. The mixture was then heated to 80 ° C and stirred at this temperature for 45 minutes. The suspension was filtered on a Bttchner suction and washed with warm water at 40 ° C. The product was dried at 80 ° C and ground.

The treated phthalocyanine pigment disperses well in toluene using a high speed stirrer. The intaglio ink prepared using toluene paste has good flow properties and provides quality test prints.

- 4 Example 2 _{23β 324}

The same results as in Example 1 were achieved with 8 to 20 wt% palmitic acid monoethanolamide, stearic acid monoethanolamide, oleic acid monoethanolamide or mixtures of these alkanolamides dissolved in ethanol or glacial acetic acid.

Claims (1)

Process for treating phthalocyanine pigments of beta modification by grinding copper phthalocyanine in glycol environment II0 (CH ₂ CH ₂ 0) _r H wherein η = 1 to 200, in the presence of sodium chloride at a temperature 20-150 ° C, _being characterized in that after grinding and separation of pigment ρονϊ? Ρ1ιογΘ filtration and washing, the pigment is adjusted akíivm ^ 'compound of formula R CO UH (CH ₂ ) _m OH | wherein R is a saturated or unsaturated aliphatic residue having a carbon number of 12 to 22, ik = 2 or 3, dissolved in ethanol or acetic acid, in an amount of 6 to 25 wt% per pigment and the product isolated.