GB2039290A

GB2039290A - Conversion of copper phthalocyanine to an easily dispersible deeply colored pigmentary form

Info

Publication number: GB2039290A
Application number: GB7941178A
Authority: GB
Original assignee: BASF SE
Current assignee: BASF SE
Priority date: 1978-11-30
Filing date: 1979-11-29
Publication date: 1980-08-06
Also published as: IT1127265B; DE2851769A1; JPS5575454A; IT7927569A0; FR2449709B1; GB2039290B; AU5330579A; FR2449709A1

Abstract

An easily dispersible deeply colored pigmentary form of copper phthalocyanine (CuPc) is obtained from crude CuPc, when the crude CuPc is milled in the absence of assistants but in the presence of from 0.5 to 15% by weight of one or more acids which have a pK of <4.9 and are non-oxidizing under the milling conditions, until a milled material is obtained in which the primary particles haves size of up to 0.1 mu m, and the milled material is then converted to the pigmentary form by heating in water in the presence of from 3 to 30% by weight of a surfactant. On isolating the product, a CuPc pigment is obtained which gives very deep colorations and is very easily dispersible in surface coatings, printing inks and plastics.

Description

SPECIFICATION Conversion of crude copper phthalocyanine to an easily dispersible deeply colored pigmentary form The present invention relates to a process for converting crude copper phthalocyanine (hereinafter referred to as CuPc) into an easily dispersible, deeply colored pigmentary form.

As a rule, CuPc as obtained from its process of synthesis is in a tinctorially valueless form. The crude CuPcs are in most cases coarsely crystalline and have a low specific surface area, when measured by the BET method. Furthermore, the crude pigments have a very heterogeneous particle size distribution. Hence, the crude pigments must be converted to tinctorially useful forms. This as a rule required special process steps.

Comminution may be effected, for example, by dissolving the crude pigment in concentrated sulfuric acid and precipitating it from water, by swelling the crude pigment in sulfuric acid of a certain concentration, or by milling it in the presence or absence of assistants. Recrystallization is in general carried out in organic fluids in the presence or absence of water. For economic and ecological reasons, the organic fluids must be recovered or worked up again, and this entails additional costs.

The present invention seeks to provide a process by means of which an easily dispersible, deeply colored CuPu pigment may be obtained without use of a solvent, preferably by means of a process which is technically simple and does not pollute the environment.

We have found that crude CuPu can be converted into an easily dispersible deeply colored pigmentary form by milling the crude pigment in the absence of assistants until the milled material consists of agglomerates which are composed of primary particles of < 0.1 um in size, followed by heating the milled material in water in the presence of from 3 to 30 percent by weight, based on the milled material, of a surfactantto recrystallize the pigment, and isolating the pigment, if a milled material is used which has been obtained by milling a mixture of crude CuPc and from 0.5 to 15 percent by weight, based on crude pigment, of one or more acids which have a pK of < 4.9 and are non-oxidizing under the milling conditions.

The pigments obtained by the process according to the invention have in general a high tinctorial strength and very good dispersibility in surface coatings, printing inks and plastics.

Compared to the CuPc pigments obtainable by the process of German Laid-Open Application DOS 2,745,893, which is to be regarded as the closest prior art, the pigments obtained by the process according to the invention are in general more deeply colored and more easily dispersible, and give more brilliant, purer colorations.

The crude CuPc can be prepared by conventional methods, for example from phthalic anhydride and urea or from phthalodinitrile or in accordance with conventional variants of these methods.

The milled material to be used for process according to the invention is obtained by milling a mixture of crude CuPc and from 2 to 15 percent by weight, based on the crude pigment, of one or more acids of the stated type. Ball mills, vibratory mills or other units having a similar action are suitable for use. The milling process is terminated when the agglomerates in the milled material are composed of primary particles whose size (length) is < 0.1 lim, preferably from 0.01 to 0.05 1lem.

Depending on the crude CuPc used, this primary particle size is usually achieved after a milling time of from 10 to 50 hours, in most cases after from 20 to 35 hours.

The amount of acid of the stated type is from 0.5 to 15, preferably from 1 to 10, especially from 2 to 7, percent by weight, based on crude Cups.

Examples of acids which have a pK of < 4.9 and are non-oxidizing under the milling conditions are sulfuric acid, phosphoric acid, C1-C20-alkanesulfonic acids, alk-1-enesulfonic acids and 2-hydroxyalkanesulfonic acids of 8 to 20 carbon atoms in the alkene or alkane radical, benzenesulfonic acid and the naphthalenesulfonic acids, in which the benzene or naphthalene radical may be substituted by 1 or 2 C1-C20-alkyl groups and,or by one hydroxyl group, sulfuric acid half-esters of C1-C20-alkanols, C1-C4-alkanoic acids, monochloroacetic, dichloroacetic and trichloroacetic acids, trifluoroacetic acid, maleic acid, dihydroxymaleic acid, tartaric acid, dihydroxytartaric acid and mixtures of two or more of the above.

Specific examples of acids, in addition to those mentioned, are: a) as C1-C20-alkanesulfonic acids: methane-, ethane-, propane-, butane-, hexane-, octane-, decane-, dodecane-, tetradecane-, hexadecane- and octadecanesulfonic acid; b) as alk-1-ene-1-sulfonic acids and 2-hydroxyalkane-1-sulfonic acids; tetradec-1-ene-1-, octadec-1-ene-1-, 2-hydroxy-tetradecane-1 - and 2-hydroxy-octadecane-1 -sulfonic acid; c) as sulfuric acid half-esters of C1-C20-alkanols: the sulfuric acid half-esters of methanol, ethanol, propanol, butanol, hexanol, octanol, decanol, dodecanol, tetradecanol, hexadecanol and octadecanol; d) as benzenesulfonic and naphthalenesulfonic acids which may be substituted by alkyl and,or hydroxyl: benzenesulfonic acid, phenolsulfonic acid, o- and p-toluene-sulfonic acid, xylenesulfonic acid, o- and p-ethylbenzene-sulfonic acid, p-tert.-butylbenzenesulfonic acid, o-hydroxy-tert.-butylbenzenesulfonic acid, p-hexylbenzenesulfonic acid, p-octylbenzenesulfonic acid, p-nonylbenzenesulfonic acid, pdodecylbenzenesulfonic acid, p-hexadecylbenzene-sulfonic acid, p-octadecylbenzenesulfonic acid, o hydroxy-m,m-bis-dodecylbenzenesuifonic acid, o-hydroxy-nonylbenzene-sulfonic acid, ohydroxydodecylbenzenesulfonic acid, o-hydroxy-hexadecylbenzenesulfonic acid, o-hydroxy-octadecylbenzenesulfonic acid, a- and lS-naphthalenesulfonic acid, butylnaphthalenesulfonic acid, dodecylnaphthalenesulfonic acid, didodecylnaphthaienesulfonic acid, octylnaphthalenesulfonic acid, dioctylnaph thalenesulfonic acid, dodecyinaphthol-1-sulfonic acid, didodecyinaphthol-1-sulfonic acid, octylnaphthol-1 - sulfonic acid and dioctylnaphthol-1-sulfonic acid.

For economic reasons, preferred non-oxidizing acids are concentrated (from 90 to 100 % strength by weight) sulfuric acid, concentrated (from 85 to 100% strength by weight) phosphoric acid, formic acid, glacial acetic acid, trichloroacetic acid, methanesulfonic acid, the toluenesulfonic acids, the naphthalenesulfonic acids, propionic acid and mixtures of two or more of these.

After milling, the milled material is introduced into water. The surfactants required for finishing the pigment may be added to the water beforehand, or may be added to the suspension of milled material in water, or may be added conjointly with the milled material to the water. The amount of water is not critical provided the suspension can be mixed thoroughly before, during and after the heat treatment. For economic reasons, the concentration of milled material is kept as high as is possible if the mixture is to remain stirrable and mixable. Advantageously, the amount by weight of water is from 2 to 10, preferably from 3 to 5, times the amount by weight of the milled material.

In the aqueous suspension, the recrystallization of the primary particles to the pigmentary form in general takes place at above 50"C, especially at from 80 to 700C. Preferably, the temperature used is from 80"C to the boiling point of the mixture; more especially, carrying out the treatment at the boil is preferred.

The recrystallization can also be carried out at from 100 to 170C under pressure. When carried out at the boil, the recrystallization is as a rule complete after from 2 to 15 hours. The time required depends not only on the temperature but also on the nature and amount of the surfactant.

Suitable surfactants are anionic, cationic or non-ionic. The amount of surfactant is from 3 to 30 percent by weight, preferably from 5 to 15 percent by weight, based on the milled material. It would also be possible to use more than 30 percent by weight of surfactant, but this increased amount would offer no advantages, for example no improvement in the pigmentary form obtained.

Examples of anionic surfactants for use in the process are half-esters of sulfuric acid with C6-C20-alkanols, 2-hydroxyalkanesulfonic acids of 8 to 20 carbon atoms, sulfuric acid half-esters of C8-C20-alkylphenol polyglycol ethers and C6-C20-alkylbenzenesulfonic acids, in the form of the alkali metal, ammonium, monoethanol-ammonium or diethanolammonium salts.

Examples of cationic surfactants are C8-C20-alkylamines, salts of C,5-C20-fatty acids with monoethanolamine, diethanolamine and triethanolamine, esters of C8-C20-fatty acids with ethanolamine, esters of oleic acid with monoethanolamine, diethanolamine and triethanolamine, and water-soluble polymers of ethyleneimine.

Examples of non-ionic surfactants are amides, hydroxy-C2-C3-alkylamides and bis-(hydroxy-C2-C3-alkyl)amides of C8-C20-fatty acids, C8-C20-alkanols, polyethylene oxide, polyalkylene oxides obtained from propylene oxide and ethylene oxide, adducts of ethylene oxide, propylene oxide or propylene oxide and ethylene oxide with C8-C20-fatty acids, with C8-C20-fatty acid amides, with C8-C20-alkanols, with C6-C20alkylphenols, with C8-C20-fatty acid ethanolamides, with C8-C20-fatty acid ethanolamine esters, with C8-C20-alkylamines, with oleylamine, with aliphatic diamines and polyamines, with cycloaliphatic monoamines and diamines and with benzenearomatic monoamines and diamines, or mixtures of the above.

Specific examples of surfactants, in addition to those already mentioned, are: a) amongst anionic surfactants: octyl sulfate, nonyl sulfate, decyl sulfate, lauryl sulfate, tetradecyl sulfate, hexadecyl sulfate and octadecyl sulfate; 2-hydroxytetra-decanesulfonic acid and 2hydroxyoctadecanesulfonic acid; p-hexylbenzenesulfonic acid, p-octylbenzenesulfonic acid, pnonylbenzenesulfonic acid, p-decylbenzenesu Ifonic acid, p-dodecylbenzenesulfonic acid, phexadecylbenzenesulfonic acid and p-octadecylbenzenesulfonic acid in the form of the salts, and octylphenol, nonylphenol, decylphenol, dodecylphenol and tetradecylphenol polyglycol ether sulfate in the form of the salts.

b) Amongst cationic surfactants; octylamine, nonylamine, decylamine, dodecylamine, hexadecylamine and octadecylamine, diethanolamine salts of stearic acid, palmitic acid and oleic acid, and monoethanolamine, diethanolamine and triethanolamine esters of caprylic, capric, lauric, myristic, palmitic and stearic acid.

c) Non-ionic surfactants: am ides, hydroxyethylamides and bis-(hydroxyethyl)-amides of caprylic, capric, lauric, myristic, palmitic and stearic acid; C8-C20-alkanols, eg. octanol, 2-ethylhexanol, nonanol, decanol, dodecanol, tetradecanol, hexadecanol and octadecanol; adducts of from 2 to 30 miles of ethylene oxide with the above C8-C20-alkanols, with the above fatty acid amides and hydroxyethylamides, with C8-C20-fafly acids, eg. caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid or oleic acid, with C6-C20-alkylphenols, eg. 4-hexyl-phenol, 4-octylphenyl, 4-nonylphenol, 4-decyiphenol, 4-dodecyiphenol, 4-tetradecylphenol, 4-hexadecylphenol and 4-octadecylphenol, with ethanolamine, diethanolamine and triethanolamine esters of the above fatty acids, with C8-C20-alkylamines, eg. octylamine, 2-ethylhexylamine, nonylamine, decylamine, dodecylamine, tetradecylamine, hexadecylamine and octadecylamine, with aliphatic diamines and polyamines, eg. ethylenediamine, diethylenetriamine, triethylenetetramine, propylenediamine, dipropylenetriamine and tripropylenetetramine, with aniline, with m- or p-phenylene diamine, with cyclohexylamine and with bis-aminocyclohexane.

Preferably, non-ionic surfactants are used for the process according to the invention.

Preferred surfactants, because of their advantageous effect on the recrystallization of the particles, are oleic acid amide, monoethanolamide and diethanolamide and oxyethylated oleic acid amide or ethanola mide (with from 5 to 15 moles of ethylene oxide (EO)); the diethanolamine and triethanolamine esters of oleic acid; oxyethylated C8C20-alkylphenols, eg. oxyethylated octylphenol, nonylphenol, decylphenol, dodecylphenol, tetradecylphenol and hexadecylphenol (with from 10 to 25 moles of EO), oxyethylated C8-C20-alkanols, eg. octanol, decanol, nonanol, dodecanol, tetradecanol, hexadecanol, octadecanol and oleyl alcohol (with from 5 to 20 EO); C8-C18-alkylphenol polyglycol ether sulfates, eg. octylphenol, nonylphenol, decylphenyl, dodecylphenol and tetradecylphenol polyglycol ether sulfate (with from 2 to 6 moles of EO per phenol), and C8-C16-alkanols, eg. octanol, 2-ethylhexanol, nonanol, decanol, tetradecanol and hexadecanol, or mixtures of these compounds.

Where a sulfuric acid half-ester of a C8-C20-alkanol is used as the acid for milling the crude CuPc, the addition of a surfactant to the aqueous phase is unnecessary, since under these conditions, especially at above 80"C, the free sulfuric acid half-ester hydrolyzes to the alkanol and sulfuric acid, thereby producing a non-ionic surfactant.

When using a C8-C20-alkylbenzenesulfonic acid as the acid during milling, the addition of a surfactant for the heat treatment in water is again not necessary. By adding preferred and hence more effective surfactants the recrystallization of the fine particles can however be accelerated.

The Examples additionally illustrate the process according to the invention.

Example 1 a) 1,140 g of crude CuPc and 60 g of concentrated sulfuric acid are milled for 35 hours in a ball mill (capacity 10 liters, filled with 15.5 kg of iron balls of 2-3 cm diameter). A dry dark blue milled product, having a slight metallic luster and possessing an increased bulk density, is obtained. According to an X-ray diagram, more than 70 % of the milled material is in the form of the a-modification. The milled material consists of agglomerates of up to 250 Ltm in size, composed of primary particles of from 0.01 to 0.05 um in size.

b) 10 g of oleic acid diethanolamide are stirred into 300 g of water and 105 g of the milled material from a) are introduced, The mixture is heated to the boil and kept in this temperature for 4 hours. The product is then filtered off and washed, and the press cake is dried at 80"C. Yield: 105 g of CuPc pigment in the B-modification. After milling in a pin-disk mill, the pigment exhibits excellent dispersibility in printing inks, surface coatings and plastics.

Examples 2 to 5 The procedure followed is as described in Example I b), except that the surfactant shown in the Table is used. The milled material employed is that obtained as described in Example 1a).

Example Surfactant (g) 2 10 oleic acid amide 3 10 oleic acid amide + 10 miles of ethy lene oxide per mole of amide 4 10 sodium salt of the sulfuric acid half-ester of n-nonanol 5 10 sodium salt of the sulfuric acid half-ester of n-dodecanol.

The CuPc pigments obtained have virtually the same properties as the pigment obtained as described in Example 1 b).

Example6 105 g of the CuPc milled product prepared as described in Example 1 a) are added to a solution of 10 g of oxyethylated nonylphenol (20 moles of ethylene oxide per mole of phenol) in 500 g of water. The suspension is then heated to the boil and kept at this temperature for 6 hours, with stirring. It is then filtered and the filter residue is washed with water and dried at 800C. Yield: 98 g of a CuPc pigment which has virtually the same properties as that obtained as described in Example 1 b).

Example 7 105 g of the CuPc milled product described in Example 1a) are added, whilst stirring, to a mixture of 300 g of water and 10 g of a mixture of 1 mole of stearic acid and 2 moles of diethanolamine. The suspension is then heated to the boil and kept at this temperature for 10 hours. It is then filtered and the filter residue is washed with water and dried at 80"C. Yield: 106 g of a CuPe pigment which has the same properties as that obtained as described in Example 1 b).

Example 8 105 g of the milled product described in Example 1 a) are introduced into a solution of 10 g of nonylphenol polyglycol ether sulfate (4 moles of ethylene oxide per mole of phenol; the compound is used as the sodium salt) in 300 g of water. The mixture is heated to the boil, whilst stirring, and kept at this temperature for 6 hours. It is then brought to pH 2 with hydrochloric acid and the suspension is boiled for a further 2 hours.

Thereafter it is filtered and the filter residue is washed with water and dried at 80'C. Yield: 104 g of a pigment which has virtually the same tinctorial properties as that obtained as described in Example 1 b).

Example 9 a) 900 g of crude CuPc and 10 g of methanesulfonic acid are milled for 35 hours in the ball mill described in Example 1 a). A dry, dark blue milled product, having a slight metallic luster and possessing an increased bulk density, is obtained.

b) 10 g of oleic acid diethanolamide are stirred into 400 g of water and 100 g of the milled material obtained in a) are then introduced. The mixture is heated to 100 C whilst stirring, and is kept at this temperature for 10 hours. It is then filtered and the filter residue is washed with water and dried at 80"C. Yield: 105 g of CuPc pigment, which is very easily dispersible in printing inks, surface coatings and plastics, and possesses high tinctorial strength.

Example 10 a) 850 g of crude CuPc and 150 g of the sulfuric acid half-ester of dodecanol are milled for 30 hours in the ball mill described in Example 1 a). A dry dark blue product having a slight metallic luster is obtained, which consists for the mort part of agglomerates composed of primary particles of from 0.01 to 0.05 ttm in size.

b) 5 g of concentrated sulfuric acid are dissolved in 400 g of water and 100 g of the milled material obtained as described in a) are then introduced. The mixture is heated to the boil, whilst stirring, and is kept at this temperature for 8 hours. The product is then filtered off, washed with hot water (80CC) and dried at 80"C.

Yield: 90 parts of a CuPc pigment which has virtually the same tinctorial properties as that obtained as described in Example 9.

Example 77 105 g of the milled product prepared as described in Example 1 a) are added, whilst stirring, to a mixture of 300 g of water and 15 g of the triethanolamine ester of oleic acid. The pigment suspension is heated to the boil and kept at this temperature for 8 hours. The product is then filtered off, washed with water and dried at 80-C. Yield: 108 g of a CuPc pigment which in printing inks exhibits a high tinctorial strength and very good dispersibility.

Example 12 105 g of the milled product obtained as described in Example 1a) are introduced into a mixture of 400 g of water and 12 g of the triethanolamine salt of dodecylbenzenesulfonic acid. The mixture is heated to the boil, whilst stirring, and kept at this temperature for 6 hours. It is then filtered and the press cake is washed and dried at 80;. A pigment in the lA-modification is obtained, which exhibits very good dispersibility in printing inks, surface coatings and plastics. (Yield: 99 g).

Claims

1. A process for converting crude copper phthalocyanine into an easily dispersible deeply colored pigmentary form by milling the crude pigment in the absence of assistants until the milled material consists of agglomerates which are composed of primary particles of < 0.1 um in size, followed by heating the milled material in water in the presence of at least 3 /0 by weight, based on the milled material, of a surfactant to recrystallize the pigment, and isolating the pigment, wherein a milled material is used which has been obtained by milling a mixture of crude copper phthalocyanine and from 0.5 to 15 percent by weight, based on crude pigment, of one or more acids which have a pK of < 4.9 and are non-oxidizing under the milling conditions.

2. A process as claimed in claim 1, wherein a milled material comprising crude copper phthalocyanine and from 1 to 10 percent by weight, based on crude pigment, of one or more of the acids defined in claim 1 is used.

3. A process as claimed in claim 1, wherein a milled material comprising crude copper phthalocyanine and from 2 to 7 percent by weight, based on crude pigment, of one or more of the acids defined in claim 1 is used.

4. A process as claimed in claim 1,2 or 3, wherein a milled material is used which contains, as the acid which is non-oxidizing under the milling conditions and has a pK of < 4.9, concentrated sulfuric acid, concentrated phosphoric acid, a C1-C20-alkanesulfonic acid, an alk-1-enesulfonic acid or 2hydroxyalkanesulfonic acid of 8 to 20 carbon atoms in the alkene or alkane radical, benzenesulfonic acid or a naphthalenesulfonic acid, in which the benzene radical or naphthalene radical may be substituted by 1 or 2 C1-C20-alkyl groups and our by one hydroxyl group, a sulfuric acid half-ester of a C,-C20-alkanol, a C1-C4-alkanoic acid, monochloroacetic acid, dichloroacetic acid or trichloroacetic acid, trifluoroacetic acid, maleic acid, dihydroxymaleic acid, tartaric acid, dihydroxytartaric acid or a mixture of two or more of these.

5. A process as claimed in claim 1, 2 or 3, wherein a milled material is used which contains, as the acid which is non-oxidizing under the milling conditions and has a pK of < 4.9, to 100 % strength by weight sulfuric acid, 85 to 100 % strength by weight phosphoric acid, formic acid, glacial acetic acid, propionic acid, trichloroacetic acid, methanesulfonic acid, a toluenesulfonic acid, a naphthalenesulfonic acid or a mixture oi two or more of these.

6. A process as claimed in any of claims 1 to 5, wherein the recrystallization is carried out at from 80 to 1 70DC.

7. A process as claimed in any of claims 1 to 5, wherein the recrystallization is carried out at from 800C to the boiling point of the mixture.

8. A process as claimed in any of claims 1 to 7, wherein the heat treatment is carried out in the presence of from 5 to 15 percent by weight, based on crude pigment, of one or more surfactants.

9. A process as claimed in any of claims 1 to 8, wherein the heat treatment is carried out in the presence of one or more non-ionic surfactants.

10. A process as claimed in claim 9, wherein the nonionic surfactant(s) used are selected from amides of C8-C20-fatty acids, their hydroxyethylamides, their hydroxy-propylamides, their bis-(hydroxyethyl)-amides and their bis-(hydroxypropyl)-amides; C8-C20-alkanols; polyethylene oxide and polyalkylene oxides obtained from propylene oxide and ethylene oxide; adducts of ethylene oxide, propylene oxide or propylene oxide and ethylene oxide with C8-C20-fatty acids, with C8-C20-fatty acid amides, with C8-C20-alkanols, with C6-C20-alkylphenols, with C8-C20-fatty acid ethanolamine esters, with C8-C20-alkylamines, with oleylamine, with aliphatic diamines and polyamines, with cycloaliphatic monoamines or diamines and with benzenearomatic monoamines or diamines, and mixture of the above.

11. A process as claimed in claim 9, wherein the non-ionic surfactant(s) used are selected from oleic acid amide; oleic acid monoethanolamide; oleic acid diethanolamide; oleic acid amide and oleic acid ethanolamide oxyethylated with from 5 to 15 moles of ethylene oxide; the diethanolamine ester of oleic acid; the triethanolamine ester of oleic acid; a C8-C20-alkylphenol oxethylated with from 10 to 25 moles of ethylene oxide; a C8-C20-alkanol oxyethylated with from 10to 15 moles of ethylene oxide; oleyl alcohol oxyethylated with from 5 to 20 moles of ethylene oxide; a sulfuric acid half-ester of a C8-CX8-alkylphenol oxyethylated with from 2 to 6 moles of ethylene oxide; a C8-C16-alkanol; or a mixture of these.

12. A process as claimed in any of claims 1 to 11, wherein the heat treatment is carried out in the presence of from 2 to 10 times the weight of water relative to the milled material.

13. A process for converting crude copper phthalocyanine into an easily dispersible deeply colored pigmentaryform carried out substantially as described in any of the foregoing Examples 1 to 12.

14. A pigmentary form of copper phthalocyanine, when obtained by a process as claimed in any of claims 1 to 13.

15. Surface coatings, printing inks and plastics when colored with a pigment as claimed in claim 14.