DE2933896A1 - Readily dispersible pigment form with high colouring strength - prepd. by grinding crude copper phthalocyanine and heating in organic solvent - Google Patents

Abstract

Copper phthalocyanine (CuPc) was converted to a form suitable for colouring use by grinding the crude prod. until it consisted of agglomerates composed of particles whose mean size was 0.05 microns or less, suspending the ground material in the 0.8-10 fold (pref. 2-8 fold) amt. by wt. of an organic solvent (1), and heating to 20-180 deg.C (pref. 50-150 deg.C) until the desired colouring strength was attained. Crude CuPc-prepd. e.g. by fusing a mixt. of o-phthalodinitrile and CuCl in anhyd. Na2SO4, and freed from salt by H2O treatment prior to grinding (10-40 hours in a ball mill, pref. 25-35 hours) - has a chlorine content of 2-4 wt.%. (1) may be amino-2-8C-alkanols (pref. 3-aminopropanol), mono- or bi-nuclear 6-membered aromatic nitrogen heterocycles (pref. pyridine), N,N-di(1-8C alkyl) amides of 1-3C carboxylic acids, N-methyl(or cyclohexyl)pyrrolid-2-one, or mixts. of these solvents. Depending on the organic solvent used, the pigment form was isolated from the mixt. either by direct filtration at 80-120 deg.C (or after treatment with H2O or aq. mineral acid) or by first removing the solvent by steam distn. and then filtering the resulting aq. suspension. The CuPc pigment forms have excellent dispersibility and high colouring strength.

Description

Process for the preparation of easily dispersible and

strongly colored pigment forms of copper phthalocyanine The present The invention relates to a process for the production of easily dispersible and strongly colored Pigment forms of copper phthalocyanine.

Usually copper phthalocyanine is synthesized in a coloristic manner received worthless form. The crude copper phthalocyanine is mostly coarsely crystalline and has a small BET specific surface area. The crude product - in the following also referred to as crude pigment - also has a very heterogeneous particle size distribution on. For a coloristic application, the crude product must therefore be used for the application suitable forms are transferred. This is done in a so-called finishing process. For this Usually two steps are required: 1. Crushing the raw pigment, e.g. by dissolving in concentrated sulfuric acid and precipitating by discharging into water, by swelling in sulfuric acid of certain concentrations or by milling in the presence or absence of grinding aids, preferably in ball mills and the like acting crushers; 2. Recrystallization of the crushed particles to defined well-formed particles. Recrystallization generally takes place in organic liquids in the presence or absence of water. Usually the organic liquid is removed, leaving the pigments at the end of the process be in the form of an aqueous suspension from which the pigments are isolated, dried and the dry material is ground.

In these treatments, reagglomeration of the pigment particles occurs on, i.e. the pigments become grain-hard and can only be used with a great deal of energy be dispersed. In order to prevent or reduce this agglomeration, are the pigment particles on the surface before isolation with surfactants Agents or with resins that become insoluble by changing the pH. There for Occupancy mostly amounts between 5 and 20%, based on the pigment, required are, these coated pigments are only for a narrowly defined area of application suitable.

The object of the present invention was to find a method after the strongly colored and easily dispersible pigment forms of copper phthalocyanine are obtained that are free of occupancy funds.

It has been found that raw copper phthalocyanine is readily dispersible and strongly colored pigment forms by grinding raw copper phthalocyanines in the presence or absence of grinding aids until the grist consists of agglomerates, composed of particles with a mean primary particle size of <0.05 / µm are, suspending the millbase in organic liquids, heating to temperatures between 20 and 1800C and isolating the pigment if Ban as raw pigment raw copper phthalocyanine with a chlorine content of 2 to 4 wt .-% is used and than organic liquids Amino-C2- to C8-alkanols, mononuclear or binuclear 6-membered aromatic heterocycles with basic nitrogen as Ring member, N, N-di (01- to C8-alkyl) -amides of C1- to C3-carboxylic acids, pyrrolidone, N-methylpyrrolidone, N-cyclohexylpyrrolidone or mixtures thereof are used.

The process according to the invention gives copper phthalocyanine (CuPc) pigments, which deliver very strong colors in the white blend and which are very easily dispersible in the application medium. The pigments obtained are universally applicable.

The process according to the invention is generally carried out so that the millbase is poured into the organic liquid presented at room temperature enters and, depending on the liquid, heated to temperatures of up to 1800C. If the the desired color strength is achieved, the suspension is worked up in the usual way and isolate the CuPc pigment.

Raw CuPc, which has a chlorine content of approx 2 to 4% by weight. Such products are made e.g. after the baking process a mixture of o-phthalonitrile and cupric chloride in anhydrous sodium sulfate or from a mixture of phthalic anhydride, 4-chlorophthalic acid (anhydride), urea, Obtained copper-I-chloride and anhydrous sodium sulfate.

The process product can be ground directly. But it can also first coarsely ground and freed from salt by adding to warm water, filtered, washed and dried and used as salt-free crude CuPc for grinding. A corresponding crude CuPc can also be synthesized in solvents from o-phthalonitrile and cuprous chloride can be produced in the absence of bases. The raw products be in the present or preferably in the absence of grinding aids such as rock salt, sodium sulfate, calcium chloride, in ball or vibrating mills 10 to Ground dry for 40, preferably 25 to 35 hours. After this time it is CuPc in the ground stock in the form of agglomerated particles, the mean particle size of which is 0.05 µm and below.

The CuPc in the regrind of 80% by weight and above is in the i-modification before.

If the process product containing sodium sulfate is direct or salt-free Crude CuPc ground in the presence of grinding aids in a ball or vibration mill, so the CuPc is only agglomerated to a small extent. When grinding salt-free raw CuPc on the other hand, a very strongly agglomerated grist is obtained, in which the agglomerates are composed of primary particles of the size indicated above.

As organic liquids come for the method according to the invention into consideration: a) amino-C2- to C8-alkanols, such as ethanolamine, 3-aminopropanol, i-ethylaminobutanol-2; b) mononuclear and binuclear 6-membered aromatic heterocycles with basic nitrogen as a ring member such as pyridine, the picolines, quinoline, quinaldine, lepidine; c) N, N-Di- (C1- to C8-alkyl) amides of C1- to C3-carboxylic acids such as N, N-dinethylformamide, N, N-diethylformamide, N, N-dimethylpropionamide, N, N-dipropylpropionamide, pyrrolidone, N-methylpyrrolidone and N-cyclohexyl pyrrolidone.

Mixtures of these liquids can also be used.

Organic liquids are N-methylpyrrolidone, 3-aminopropanol, Pyridine and 1-cyclohexylpyrrolidone-2 are preferred.

The concentration of grist in the liquid is chosen so that the suspension is still stirrable and flowable. On the formulation, i.e. on the concentration has no recrystallization of the millbase into the pigment form Influence. It is expedient to use the 0.8 to 10, preferably the 2 to 8 fold Amount by weight, based on the regrind, of organic liquid.

The formulation is based on the liquid used Temperatures between room temperature (approx.

200C) and 1800C, preferably between 50 and 1500C.

The duration of the temperature treatment depends mainly on the one used Liquid dependent. It is also true that the duration of the temperature treatment of the Temperature is dependent. The temperature treatment continues until the desired Color strength is reached.

The mixture of the pigment and the organic liquid is in usually worked up depending on the liquid used. So can the pigment e.g.

filtered off from the liquid at 80 to 120 0C, the mother liquor displaced by suitable washing liquid and, if necessary, the latter displaced by water and so washed free of the organic liquid.

In the case of liquids soluble in water, the suspension can diluted with water and the pigment tared and washed will.

In the case of basic liquids soluble in dilute mineral acids like quinoline and quinaldine, these can be made water-soluble by adding dilute mineral acid made, the pigment separated and washed out with water.

Another possibility is given when using the liquid Water vapor is highly volatile. In this case, the liquid can with water vapor removed and the pigment isolated from the aqueous residue. The pigment is filtered off and washed.

The filter material can either be used directly or - which is the rule is - to be dried. This is advantageously done under gentle conditions, e.g. at 50 to 800C.

The following exemplary embodiments are intended to implement the method according to FIG Explain the invention additionally. The percentages given below relate to focus on the weight.

Example 1 a) 100 g of the milled product described under b) registered in 500 g of N-methylpyrrolidone. The suspension is 1 hour at 16o0C stirred, the pigment is filtered off at 800C, free of N-methylpyrrolidone with water washed and dried. After grinding, powdery pigment is obtained which is excellently dispersible.

t) In a ball mill (volume: 10 m3, filled with 15.5 t iron balls, Diameter between 2 and 3 cm) 1,200 kg parts of raw copper phthalocyanine (3.5 % Chlorine) ground for 30 hours. The result is a dark blue, partly metallic shiny powder with increased bulk density. There is a high proportion in the X-ray diagram (> 80%) can be recognized by the i-modification.

Example 2 100 g of the millbase obtained according to Example Ib) registered in 600 g of 3-aminopropanol and the suspension stirred at 150.degree. C. for 8 hours. The liquid is then distilled off by introducing steam. The pigment is filtered, washed, dried and ground.

In the white blend, the pigment gives very strong colorations and is very easy to disperse.

Example 3 100 g of the millbase obtained according to Example lb) registered in 500 g of quinoline and stirred the suspension at 1200C for 6 hours. at 800C, 1,500 g of water are then added and 400 g of concentrated hydrochloric acid are added. The suspension is stirred for 1 hour at 80 to 90 ° C., then filtered with warm Water washed neutral and dried.

A CuPc pigment is obtained which is very readily dispersible and has colorations with high color strength.

Example 4 100 g of the millbase obtained according to Example lb) entered in 600 g of pyridine. The suspension is heated to boiling while stirring (Duration: 1 hour). The mixture is then allowed to cool and diluted with 1200 g of water at approx. 80 ° C.

The pigment suspension is filtered, free of pyridine with warm water washed and dried the filter material.

A CuPc pigment is obtained which is very easily dispersible and in the white blending gives very strong colorations.

Example 5 100 g of the milled product obtained according to Example lb) entered in 200 g of dimethylformamide and the mixture was stirred at 155 ° C. for 8 hours. It is then cooled to approx. 800 ° C., diluted with 500 g of H20 and filtered off with suction. The filter material is washed DMF-free with water and dried.

A pigment with very good and high dispersibility is obtained Color strength.

Example 6 In 500 g of N-cyclohexylpyrrolidone, 75 g of the according to Example lb) received grist registered. The mixture is heated to 1400C with stirring and held at this temperature for 2 hours. It is then cooled to 80 ° C. and with 1000 g of water diluted. The pigment suspension is filtered off, the filter material with warm water solution Washed medium-free and dried at 800C.

One obtains an easily dispersible in solutions of coating resins and strong pigment.

Claims (2)

Claims 1. Process for the preparation of easily dispersible and strongly colored pigment forms of copper phthalocyanine by grinding raw copper phthalocyanines in the presence or absence of grinding aids, until the grist has agglomerated consists of particles with a primary particle size of # 0.05 µm, Suspending the millbase in organic liquids, heating the suspension to temperatures between 20 and 180 0c and isolating the pigment, characterized in that that as a crude pigment, crude copper phthalocyanine with a chlorine content of 2 to 4% by weight and, as organic liquids, amino-C2- to C8-alkanols, mono- or binuclear 6-membered aromatic heterocycles with basic nitrogen as ring member, N, N-dibis to C8-alkyl) amides from Gi to C3-carboxylic acids, pyrrolidone, N-methylpyrrolidone, N-cyclohexylpyrrolidone or mixtures thereof are used. 2. The method according to claim 1, characterized in that as organic liquids quinoline, quinaldine, N, N-dimethylformamide or N-methylpyrrolidone applies.