DE2131617B2 - Pigment composition and its preparation - Google Patents

Description

The suitability of a pigment for dispersion in a particular medium for a particular application can in the form of theological properties that Color strength, gloss, transparency, color tone and the wettability or dispersion properties, showing the pigment in the medium. In general, all of these values can be related to the crystallographic properties of the pigment and too the surface properties of the pigment particles that are to a considerable extent interdependent, are related.

It is known that the surface of organic Pigment particles can be modified by adding a wide variety of surface-active agents to the particles Agents or solvents adsorbed or added such compounds during pigment formation available. It has been found that it is possible in this way to express the theological properties of the Pigments and thus the degree of dispersion in printing inks and color media to change, whereby one Obtains improvements in the transparency and gloss of the pigment.

The invention relates to a pigment composition which is characterized in that it contains fine particles of a monoazo pigment of the acetoacetarylide series or a disazo pigment of 1 Mol 6ΪΠ «tetrazolated diaminodiphenyl and 2 moles of an acetoacetarylide made from a different monoazo pigment of the acetoacetarylide series or disazo pigment of the acetoacetarylide series of a tetrazotized diaminodiphenyl and 2 moles of an acetoacetarylide are coated.

The pigment composition according to the invention

is obtained by preparing a slurry from a monoazo pigment of the acetoacetarylide series or from a disazo pigment from 1 Mo) of a tetrazotized diaminodiphenyl and 2 mol of an acetoacetarylide and therein precipitation of a different monoazo pigment of the acetoacetarylide series or disazo pigment from 1 mol of a tetrazotized diaminodiphenyl and 2 mol of an acetoacetarylide by coupling the first pigment

DE-OS 14 44 274 discloses a pigment composition composed of an organic pigment and a basic one Pigment derivative known, the production of which by joint grinding, by aqueous precipitation of both components from acidic solution, by treating

is treatment of the pigment with a solution of the pigment derivative or by incorporating the mixture of pigment and pigment derivative into a non-aqueous one Application medium, in which the pigment deficiency is soluble is done. The pigment derivative, which is soluble in a non-aqueous medium, draws the pigment and is intended to do so Piement composition improved: resistance confer against flocculation and crystallization in non-aqueous media. In contrast, according to the invention em first insoluble pigment coated with a second insoluble pigment, which increases The luster and transparency of the pigment composition fOhn. In addition, the inventive Pigment composition easily by coupling and precipitating the second pigment in the slurry the first pigment, d. H. in the same reaction vessel, manufacture, while the manufacture of said pigment mass requires additional operations before the basic pigment derivative precipitated from the solution and is deposited on the first pigment.

The invention is for arylide and diarylide pigments applicable, which are prepared by, for example, a diazotized nitralinine or a tetrazotized 3,3'-dichlorobenzidine, which is found in the aromatic The nucleus may contain further substituents, it generally couples with an acetoacetarylamide 3'3-dichlorobenzidine used itself, but you can also use tetrachlorobenzidine, for example. Examples of coupling agents that are used are acetoacetanilid, acetoacet-o-toluidid, acetoacet-p-toluidid, Acetoacet-o-anisidide and acetoacet-2,4-xylidide.

Monoazo and disazo pigments are generally used produced by the diazotized or tetrazotized component with the coupling agent in

so acidic aqueous medium coupling. After coupling, the reaction mixture is heated to the boil, and that Pigment is being worked up Two parameters of the resulting pigment are important: the average primary particle size and the average

«Average Kf! Manipulated variable within each particle, and it has been found that better rheological properties can be obtained if the pigments are used in printing ink media are incorporated, have a large average crystal size, which in fact differs from the approximates average primary particle size with this on average for all primary particle sizes of the pigment applies. In the present invention, a first pigment is used for an internal Core taken, the surface of which with a full stänhi present or partial coating of another pigment similar structure is modified. For example, the pigment that can be obtained by coupling Acetoacet-o-anisidide with tetrazotized 3.3'-DiChIOr-

benzidine in the form of small crystals (amorphous in X-ray powder photography), bad Flow properties in printing inks, whereas the pigment, which is obtained by coupling acetoacet-m-xylidide obtained with tetrazotized 3ß'-dichlorobenzidine in the form of large crystallites, good flow properties possesses a pigment composition of particles of acetoacet-o-anisidide coupled with tetrazotized a ^ '- dichlorobenzidine, coated with particles from Acetoacet-m-xylidide, coupled with tetrazotized 3,3'-dichlorobenzidine, combines the desirable properties of both pigments.

EHe pigment compositions according to the invention are prepared in the following manner: prepares a slurry of the first pigment and then falls in that slurry the second pigment by coupling off, so that part of the second pigment on the already existing nuclei of the the first pigment is precipitated and Ms? assumes part of the second organic pigments in formation during the Precipitation process on existing crystallites of the first pigment at high-energy active sites, such as at Dislocation sites, grows This peeling occurs even if the second pigment is only in The first pigment can be prepared in a coupling solution, and is present in small proportions then the second pigment is made in the same solution without the need for the first Isolate pigment. For the two pigments one can use the same or different coupling agents.

Proof that. the pigment core is withdrawn, can be produced as follows: If a pigment core made of acetoacet-m-xylidide, coupled with tetrazo-S ^ '- dichlorobenzene, is treated in such a way that one must assume, according to the present invention, that a pigment coating made of acetoaceto- anisidide, coupled with tetrazo 3,3'-dichlorobenzidine, is produced, and if one mung stage the system in Aufschläm- * n heated to boiling, the crystal growth of the nuclei is inhibited by the pigment coating This is shown by X-ray crystal structure analysis if on the other hand a physical mixture of the slurries obtained by mixing freshly made acetoacet-m-xylidide coupled with tetrazo-33'-dichlorobenzidine and freshly made acetoacet-o-anisidide coupled with tetrazo-3,3'-dichlorobenzidine , ie a slurry which has not been obtained by coprecipitation is heated to the boil, there is no inhibition of the growth of the crystalline parts hen watch in the core.

The effect of the present invention is that a coating or a partial coating of the further. Pigment is formed on the core of the first pigment. The optical properties of the pigment core are not changed much because the optical properties of the composition are somewhere lie between the properties of both pigments. A composition is obtained which has the optical Properties of the first pigment, but has the surface properties of the second pigment, when the pigment used for the practice drawing is only present in small quantities.

The disazo core pigment can be found by the formula

B-N = N-A-N = N-B

represent, wherein A is the tetrazo component and B is the coupling component. You can do this cover with:

1. D-N = N-A-N = N-D, where D is a coupling component means that differs from that used for the core pigment, or

2. B-N = N-E-N = N-B, where E is a tetra-ozone component means different from that used in the core pigment, or

3. D-N = N-E-N = N-D, in which both the Tetrazo and the coupling component of Ίεη corresponding components in the Core pigment were used, differentiate. ·

It is also possible to use a disazo pigment kerosene a monoazo pigment of the acetoacetanilide series, which is derived from the same or a different coupling component derives to cover.

Another point to consider is that that the core pigment causes the upper coating pigment adopts a special crystal modification, which differs from that which the coating pigment usually takes In such a case, the pigment that forms the core, only forms a small proportion of the composite finished pigment. In this case, the nucleus-forming pigment acts as a nucleus, which regulates the way in which the coating pigment is precipitated. The properties of the emerging Pigment composition can be controlled in this way.

The pigment compositions of the present invention can be used at any stage with any of the known ones Solvents or surfactants that are used to improve the surface properties of Modify pigments, treated. The core pigment can thus be used in the presence of conventional additives be formed or treated with this after formation. The coating pigment can also be used in Presence of known additives. Known treatments include: those with surfactants Agents, solvents, resins, amines and dyes

In the examples below, all parts and proportions are based on weight, unless otherwise stated.

example 1

A tetrazo solution was made from 19.0 parts of 3,3'-dichlorobenzidine made in 450 parts of water

164 parts of acetoacet-o-anisidide were in 225 parts Water containing 3.2 parts of sodium hydroxide in solution. Dilute acetic acid was added to this solution until the pH was below 7.

The tetrazo solution slowly became the anisidide solution added so that there was no substantial excess of the tetrazo compound present at any time. By adding a 10% sodium hydroxide solution, the pH was kept at 4.0 to 4.5 until the entire coupling component had reacted.

16.5 parts of acetoacet-m-xylidide were dissolved in 225 parts of water containing 3.2 parts of sodium hydroxide, and this solution was added to the coupling reaction mixture keeping the pH below 7.0 held.

The remainder of the tetrazo solution was then allowed to run in slowly, with an excess of

Example 3

ίο

15th

Tetrazo compound avoided and the pH by adding 10% sodium hydroxide solution above 4.0 held

The resulting slurry was boiled for 1 hour and the pigment composition was then isolated by filtration. The filter cake was washed until free of water-soluble ones Impurities was. upd then dried at 50 "C

The pigment composition was found to have an average crystal size of 0.06 μ, determined by X-ray powder diffraction spectra, and that they have excellent flux, transparency, Possessed gloss and dispersibility in ink media that were better than a simple one physical mixture of both pigments.

Acetoacet-oanisidide pigment suspension was used coupled with 3,3'-dichlorobenzidine, and of acetoacet-m-xylidide coupled with 3,3'-dichlorobenzidine, made in separate vessels and then mixed, heated to the boil and worked up, so lies the average crystal size of the particles below 0.03 μ and the connection is according to the R- = 5ntgen.itrahlbestetermung amorphous. The on! pigment composition prepared by mixing the slurries in such a manner has poor Theological Properties when incorporated into ink media is

Example 2

The procedure of Example 1 was repeated except that the ratio of coupling agents of equal parts by weight was changed to a 4: 1 molar ratio of acetoacet-o-anisidide to aeetoacet-m-xylidide Slurry of the pigment composition heated to boiling with 5% by weight of dibenzyl ether

The pigment composition was isolated by filtering the slurry, the filter cake freed from water-soluble impurities by washing and dried at 50 ° C.

The pigment composition was made into a letterpress color medium incorporated, its theological properties were found to be better than either known pigment that has been formed by coupling acetoaceto-anisidide and 3,3'-dichlorobenzidine with the same solvent treatment being applied. As in Example 1, the pigment composition possessed superior properties compared to a pigment obtained by mixing the slurries had been formed.

40

45

50

The procedure described in Example 2 was repeated except that the ratio of Coupling agent has been changed, using a 1: 4 molar ratio of acetoacet-o-anisidide too Acetoacet-m-xylidide used.

The resulting pigment composition had better gloss and transparency when incorporated into letterpress ink media as compared to a known pigment formed by coupling acetoamide-xylidide and 33'-dichlorobenzidine with the same solvent treatment. A physical mixture of the two pigments, which were prepared in separate vessels, were comparable μ mixed and worked, did not show the same gloss and transparency when they were incorporated into printing color media.

Bet game 4

The procedure of Example 2 was repeated except that acetoacetanilidide was used in place of Acetoacet-m-xylidide was used and that the ratio of coupling agents to a molar ratio from 4: t from acetoacet-o-anisidide to acetoacetaniliJ was changed.

The pigment composition formed had better rheological properties when incorporated into a Letterpress ink medium was incorporated, as the well-known pigment that by coupling of acetoacet-oanisidid and 3,3'-dichlorobenzidine was formed with the same solvent treatment. As in In Example 1, the pigment composition had superior properties as compared with a pigment obtained by mixing the prepared slurries.

. .,. · Example 5

The procedure of Example 2 .v / was repeated with the exception that acetoacet-m-xyndide is replaced by an equal molar proportion of acetoacet-o-toluidide was replaced.

The pigment composition formed had better rheological properties when incorporated into a Letterpress ink medium was incorporated, as a well-known pigment, produced by coupling of acetoaceto-anisidide and 33'-dichlorobenzidine was obtained with the same solvent treatment. As in Example 1, the pigment composition obtained had properties similar to those of a pigment which by Mixing of the prepared slurries was superior.

Example 6

a) The diazonium salt of m-nitro-p-toIuidine was prepared from 44 parts of m-nitro-p-toluidine in the usual way

52 pound parts of acetoacetanilide were divided into 1200 parts Slurried water at 5 to 6 ° C and 13.5 parts of sodium acetate were added to the pH was then adjusted to 4.8-5.0 with dilute acetic acid

The diazo solution was dripped into the slurry with stirring over 45 minutes, the pH being kept constant by the addition of dilute sodium hydroxide and no substantial excess of the diazo compound being present at any time. The slurry was then heated to 8O ⁰ C with hot steam and filtered. The product obtained in this way was washed free of salt and dried at 50 to 55.degree
When this pigment composition was incorporated into a medium for decorative paints, the color strength of the paint decreased. if the color was kept at 6O ⁰ C.

b) The procedure of a) was repeated with the exception that 10% of the Acetoacetaniüds replaced by aeetoacet-o-toluidid and the two Coupling agent mixed before coupling. The pigment composition was placed in a medium for decorative colors as in a) incorporated, and it was found that "the color strength of the color at 60 ° C only decreased slightly less than the color produced in a).

c) 44 parts of the Diazosab.es of m-nitro-p-toluidine

were made in a known manner.
4 parts of acetoacet-o-toluidide were dissolved in 0.9 parts of sodium hydroxide in 50 parts of water in a coupling vessel. Another 450 parts of water were then added at 5 to 6 ° C and the pH was adjusted to 5.0 with dilute acetic acid. Over 15 minutes, the theoretical amount of diazo salt solution of m-nitro-p-toluidine was added to to couple the toluidide completely.

48.25 parts of acetoacetanilide and 13.25 parts of sodium acetate were added to 1200 parts of water at 5 Slurried up to 6 ° C and placed in the coupling vessel. The rest of the diazo solution was then im Added over the course of 45 minutes, and the resulting pigment was, as above in a) described, worked up.

The pigment composition was incorporated into a medium for decorative colors, as described γϊ s.) , And it was found that the color strength of the color remained stable on storage at 60 ° C.

Example 7

The procedure described in Example 2 was repeated except that acetoacetanilide instead of acetoacet-m-xylidide was used and that the molar ratio of the coupling agents in 1: 3 of Acetoacet-o-aniside was changed to acetoacetanilide.

The resulting pigment composition had better gloss and transparency when used in letterpress media was incorporated in comparison with a known pigment obtained by coupling Acetoacet-o-anisidide and 33'-dichlorobenzidine have been prepared with the same solvent treatment was.

Example 8
Clutch A

A tetrazo solution was made from 27.4 parts of 33'-dichlorobenzidine in 600 parts of water.

19.4 parts of acetoacetanilide were in a coupling vessel containing 300 parts of water and 4.4 parts Sodium hydroxide contained dissolved. Dilute acetic acid was added to this solution until the pH was below 7.0 lay.

The tetrazo solution slowly became the acetoacetanilide suspension added so that there is not a substantial excess of the tetrazo compound at any time was present, the pH by adding a 10% sodium hydroxide solution at 4.0 to 4.5 was held until all of the coupling component had reacted.

22.7 parts of acetoacet-o-anisidide were in 300 parts Water containing 4.4 parts of sodium hydroxide dissolved. This solution was dissolved simultaneously with the rest of the Tetrazo solution was added to the slurry in the coupling vessel, the pH being maintained during the Kuppeins by adding the required amount of IO% sodium hydroxide solution at 4.0 to 4.5 was held. At no time was there any substantial excess on during this second dome Tetrazo compound present.

The resulting pigment slurry was then heated to boiling for 1 hour and the pigment became then isolated by filtration. The filter cake was

ίο washed free of water-soluble impurities and dried ^{at 50 0 C.}

Clutch B

A tetrazo solution was made from 27.4 parts of 33'-Difs chlorobenzidine made in 600 parts of water. Separate pigment slurries were made as follows manufactured:

Slurry 1

19.4 parts of acetoacetanilide were in 300 parts

Dissolved water containing 4.4 parts of sodium hydroxide Dilute acetic acid was added to the solution until

the pH was below 7.

300 parts of tetrazo solution slowly became the

y, acetoacetanilide suspension added so that no substantial excess of tetrazo compound was present at any point in time, the pH being be ^; * .0 to 4.5 was maintained by adding a 10% sodium hydroxide solution until the

) o had implemented the entire coupling component.

Slurry 2

22.7 parts of acetoacet-o-anisidide were dissolved in 300 parts of water containing 4.4 parts of sodium hydroxide 5.0 parts of sodium acetate were added to the coupling kettle and 250 parts of water.

The remaining 300 parts of the tetrazo solution were slowly added to the coupling vessel with the anisidide suspension given so that at no time was a substantial excess of tetrazo compound present and the pH value by adding IO% iger Sodium hydroxide solution was kept at 4.0 to 4.5, until all of the coupling component had reacted.

Slurries 1 and 2 were mixed and the resulting pigment slurry then became 1 Heated to boiling hour then the pigment was isolated by filtration, the filter cake from water-soluble Washed free of impurities and stored at 50 ° C

so dried

Was the pigment composition that was created in domes A (according to the invention Process), incorporated into a letterpress ink medium, so this was more transparent than if the pigment was obtained by coupling method B. (a process that only creates a physical mixture of the pigments)

Claims (3)

Patent claims: 1. pigment composition, characterized in that it contains fine particles of a Monoazo pigments of the acetoacetaryUd series or of a disazo pigment from 1 mol of a tetrazotized diaminodiphenyl and 2 mol of an acetoacetarylide contains those with a different monoazo pigment the acetoacetarylid series or disazo pigment from 1 mol of a tetrazotized diaminodiphenyl and 2 moles of an acetoacetarylide are coated. 2. Process for the preparation of a pigment composition according to claim 1, characterized in that a slurry is monoazo pigment the acetoacetarylid series or from a disazo pigment from 1 mol of a tetrazotized Diaminodiphenyls and 2 moles of an acetoacetarylide is prepared and a different thereof therein Monaazo pigment of the acetoacetarylide series or Disazo pigment from 1 mol of a tetrazotized diaminodiphenyl and 2 mol of an acetoacetarylide is precipitated on the first pigment by coupling. 3. The method according to claim 2, characterized in that that before the precipitation of the second azo pigment, the first or second azo pigment with an organic solvent, a surface active agent or a resin will.