TWI466956B - Process of preparing copper phthalocyanine particles exhibiting alpha crystallographic form - Google Patents

Description

Method for preparing copper phthalocyanine particles exhibiting an alpha crystal form

This application claims the benefit of European Application No. 09155545.8, filed on March 18, 2009, which is incorporated herein by reference.

The present invention generally relates to copper phthalocyanine (CuPc) and methods of making same. More particularly, the present invention relates to a new and effective and economical method for preparing CuPc pigments having better dispersibility for filters, and CuPc pigments prepared therefrom for displaying color images .

An organic pigment-based phthalocyanine is excellent in terms of non-fading property and performance. Therefore, it is typically used as a blue dye for paints or plastics. Among the pigments, copper phthalocyanine is very stable and is further desirable because it has various non-fading properties. In addition, copper phthalocyanine has a plurality of crystal forms. Among the crystal forms, those known to have practical applications include α, β and ε crystal forms of copper phthalocyanine. A common practice is to use a beta crystal form to produce a light green blue color and an alpha crystal form to produce a reddish blue color. In addition, when a blue color which is more reddish than a color produced using an alpha crystal form is required, an epsilon crystal form is used.

Different methods have been proposed for producing a phthalocyanine pigment having various crystal forms. A typical method for producing epsilon crystal form copper phthalocyanine is a solvent salt milling method in which copper phthalocyanine particles exhibiting an alpha crystal form and copper phthalocyanine particles exhibiting an epsilon crystal form are ground in an organic solvent. Regarding a method of preparing α-form copper phthalocyanine from β-form copper phthalocyanine, a coloring method using sulfuric acid (one of inorganic acids) is known in the art. That is, using an acid paste method (which is treated when the crude copper phthalocyanine is dissolved in a large amount of concentrated sulfuric acid) and an acid slurry method (using a large amount of sulfuric acid having a concentration of sulfuric acid which is insufficient to dissolve the pigment) Copper to form a sulfate).

Products obtained by acid paste or slurry processes generally have poor crystal quality and are produced in the form of agglomerates which do not exhibit desirable performance characteristics. In order to subsequently achieve optimum application characteristics, the so-called final treatment is carried out, for example, under a solvent (during the addition of the surfactant). In addition, in order to improve performance characteristics, it has been proposed in the art to produce a pigment preparation by using a phthalocyanine derivative substituted with a polar group such as sulfuric acid, a carboxylic acid or a sulfonamide group.

For example, U.S. Patent No. 3,024,247 describes a general method of acid blushing phthalocyanine after chlorinated phthalocyanine and blending a monosulfonate phthalocyanine with an acid paste aqueous slurry to produce A non-crystalline phthalocyanine coloring matter.

In addition, U.S. Patent No. 5,534,055 discloses a process for the preparation of alpha phase metal phthalocyanine pigments from crude metal phthalocyanine pigments. Such a method comprises the steps of: (a) subjecting a crude metal phthalocyanine pigment to acid paste or acid swelling; (b) subjecting the metal phthalocyanine pigment subjected to acid paste or acid swelling to dry grinding; c) final processing of the ground metal phthalocyanine pigment by intimately mixing the ground metal phthalocyanine pigment with a final treatment solvent mixture; and (d) separating the alpha phase metal phthalocyanine pigment. After acid-pastering the β CuPc to produce precipitated CuPc, the precipitated CuPc and the stabilizer are dry-milled in the presence of a sulfonamide derivative of CuPc as a stabilizer to produce α CuPc.

U.S. Patent No. 6,031,030 also discloses a method of preparing a coating concentrate comprising the steps of: (a) grinding or acidifying a crude metal phthalocyanine to reduce its particle size, thereby forming a modified crude metal phthalocyanine; and (b) kneading a mixture of the modified crude metal phthalocyanine and a coating vehicle comprising one or more coating solvents to provide a coating concentrate comprising A metal phthalocyanine in the form of a pigment dispersed in a coating vehicle. It is described that the crude CuPc is ground in the presence of a refining agent such as a sulfonated CuPc to produce α CuPc.

However, the above methods for preparing α-form copper phthalocyanine have a plurality of problems because they generate very large particles, thereby requiring a large amount of time for particle size reduction and phase transformation to ε-form in the subsequent kneading step. . In addition, the performance (e.g., contrast ratio) of filter pigments prepared from prior art acid paste processes has certain disadvantages due to the poor dispersibility of the resulting pigments. Accordingly, there is a strong desire in the art to develop a process for efficiently preparing alpha crystalline copper phthalocyanine which is suitable for kneading in a more efficient manner and which is suitable for improving the performance of a final pigment for a filter. .

In order to solve the problems in the conventional preparation method (for example, longer processing time, relatively low dispersibility, contrast ratio from the generated filter pigment, etc.), the inventors of the present invention found that when in use When some additives (for example, CuPc derivatives) are added from the acid paste step of the phase inversion of the β to α crystal form, the performance of the final filter pigment and the entire processing time for producing the blue pigment can be improved.

The invention is described in detail below.

Accordingly, the object of the present invention is to prepare CuPc particles having an alpha crystal form as an intermediate for producing copper phthalocyanine particles having an ε shape, the particle size of which is very small and its dispersibility is better. This provides better performance of the filter produced from the CuPc pigment. Further, another object of the present invention is to provide a process for producing α-form copper phthalocyanine having a reduced particle size, which requires a shorter time to obtain an epsilon crystal form copper phthalocyanine having a high crystal purity. In this regard, the present invention is directed to the development of a new and more efficient method of preparing copper phthalocyanine that satisfies the above features.

Acid pasteification means that at least a portion of the crude CuPc is dissolved in a suitable acid (dissolution step) and the dissolved CuPc is precipitated in a suitable medium (precipitation step).

In the dissolving step, it is preferred to use a mineral acid such as sulfuric acid, chlorosulfonic acid and polyphosphoric acid, in particular concentrated sulfuric acid or sulfuric acid monohydrate. These acids are usually used in the form of an aqueous solution. If sulfuric acid is used, its concentration should be equal to or greater than 90% by weight, preferably equal to or greater than 95% by weight. It is preferred to use about 96% by weight of concentrated sulfuric acid. The amount of the aqueous solution to be used in the dissolution step is not limited. However, for economic reasons, the concentration of the ground crude copper phthalocyanine may be maintained within a range in which the resulting mixture may be stirred or ground and incorporated. Specifically, the amount of the aqueous solution used is 2 to 20 times, preferably 5 to 15 times, based on the weight of the crude pigment. The temperature of the dissolution step is usually from 0 ° C to 100 ° C, preferably from 5 ° C to 60 ° C, more preferably from 10 ° C to 40 ° C, such as room temperature. The duration of the dissolution step is generally from 30 minutes to 5 hours, especially from 1 hour to 3 hours, with a duration of about 2 hours being suitable.

In the precipitation step, the precipitation medium used may include water, an organic solvent or a mixture thereof, preferably water, particularly distilled water. The ratio of the precipitation medium to the acid/CuPc of the mixture formed from the dissolution step is generally from 1 to 50, preferably from 5 to 20, for example about 10. The temperature of the precipitation step may be from 0 ° C to 100 ° C, especially from 5 ° C to 60 ° C, more particularly from 10 ° C to 50 ° C, and operation at room temperature is also suitable. The mixture acid/CuPc formed from the dissolution step is usually added to the precipitation medium in a ratio of 1 g to 100 g of the mixture acid/CuPc per kg of the precipitation medium in 1 minute to 1 hour, preferably 5 minutes to 30 minutes. The inside is added in a ratio of 1 g to 100 g (mixed acid/CuPc) / kg (precipitating medium), for example, in a ratio of about 10 g (mixed acid / CuPc) / kg (precipitating medium) in about 10 minutes. Precipitation can occur under turbulent conditions.

The mixture resulting from the dissolution step is then filtered, washed with water, and dried. Preferably, the washing is carried out with distilled water, more preferably with distilled water having a pH of at least 6. For the filtration and drying steps, any filtration or drying method known in the art can be used. For example, a gravity system can be used to complete the filtration and can be dried in an oven at a temperature of, for example, 120 °C.

Such acid paste treatments are described, for example, in Ullmann's Encyclopedia of Industrial Chemistry, Fifth Completely Revised Edition, 1992, Vol. A20, pages 225-226.

In a first embodiment of the invention, copper phthalocyanine (CuPc) particles exhibiting an alpha crystalline form are prepared by:

(a) mixing coarse copper phthalocyanine particles comprising at least 50 wt% of the particles in a beta crystal form with an acid in the presence of CuPc particles substituted with at least one functional group such that at least a portion of the crude CuPc is dissolved in the acid Medium; and

(b) precipitating at least a portion of the dissolved CuPc in a medium. In a specific embodiment, the average number of functional groups per CuPc molecule is from 0.5 to 2, preferably about one.

In the dissolution step (a), the crude CuPc is preferably completely dissolved in the acid. In the dissolving step (a), the weight ratio of copper phthalocyanine and crude copper phthalocyanine substituted by at least one functional group is generally higher than or equal to 0.01, preferably higher than or equal to 0.03, and More preferably, it is higher than or equal to 0.05. Such a ratio is generally lower than or equal to 0.3, preferably lower than or equal to 0.2, and most preferably lower than or equal to 0.15.

In some specific embodiments, the functional group is selected from the group consisting of -SO ₃ M, -SO ₂ NR ₁ R ₂ , and at least one of -R ₃ -NR ₄ R ₅ , wherein R ₁ and R ₂ are independent of each other and may Selected from: hydrogen, alkyl, alkenyl, aryl or cycloalkyl; M may be a proton, ammonium cation or metal cation; R ₃ may be a single bond, an alkylene group, or an arylene group, wherein The alkylene group and the arylene group may be substituted with at least one substituent; and R ₄ and R ₅ are independent of each other and may be hydrogen, an alkyl group, an alkenyl group, an aryl group, a cycloalkyl group, or a condensed structure. The condensation structure contains at least one of -CO-, -SO ₂ - or -N=N-.

More specifically, the copper phthalocyanine particles may be selected from the group consisting of -SO ₃ H, -SO ₂ NHR ₁ and Substituted by at least one functional group, wherein R ₁ is hydrogen, alkyl, alkenyl, aryl, or cycloalkyl. More specifically, the functional group is -SO ₃ H, Or a mixture of them. In another embodiment, the CuPc particles substituted with one functional group are a mixture of at least two different substituted CuPc particles, such as CuPc particles substituted with -SO ₃ H and A mixture of substituted CuPc particles.

In another embodiment, copper phthalocyanine particles exhibiting an epsilon crystal form to be used as a blue pigment are prepared by: copper phthalocyanine particles exhibiting an alpha crystal form prepared according to the first embodiment in an organic liquid Heating at a temperature higher than or equal to 50 ° C in the presence of, and optionally grinding in the presence of beads. As defined herein, grinding means a method in which a solid is subjected to abrasion, milling, etc. to achieve a reduction in particle size. As defined herein, dry milling means a method in which the solid is subjected to wear, milling, etc., to achieve particle size reduction, substantially without liquid. However, a low level of solvent can be added.

In yet another embodiment, crystal phase transformation and particle size reduction can occur simultaneously. In this embodiment, the kneading is carried out in the presence of at least one liquid and at least one inorganic salt. Preferably, the kneading is carried out under certain temperature conditions such that the temperature profile as a function of time exhibits at least two derivatives with respect to the temperature at which time (dT/dt) is equal to zero. These two temperatures are related to a derivative equal to 0, differing by at least 10 °C. In another embodiment, the kneading is performed under a temperature profile that is constantly changing (or at least once, segmented).

Specific conditions for the kneading or heating step (eg, duration, organic liquid, liquid, beads, inorganic salts, etc.) are described in PCT Application No. PCT/EP2008/065448 and PCT/EP2008/062266, the entire contents of which are It is hereby incorporated by reference.

By adding a CuPc derivative during acid paste formation, the process of the present invention can produce an alpha crystalline copper phthalocyanine having a smaller average primary particle size, the particle size being no greater than 140 nm, preferably no greater than 100 nm. . In addition, when such a CuPc derivative is added during the acid paste process, better dispersibility of the pigment particles can be obtained, which produces an improved contrast ratio of the filter produced from the preparation of the pigment particles.

Further, in another embodiment, the CuPc particles substituted with at least one functional group are added during the kneading or heating step and during the acid paste step. For example, selected from -SO ₃ H, -SO ₂ NHR ₁ and At least one functional group-substituted CuPc particle (wherein R ₁ is hydrogen, alkyl, alkenyl, aryl, or cycloalkyl, preferably It may be present in the dissolution step (a), and the CuPc particles substituted with -SO ₃ H may be further added during the kneading or heating step, particularly during the kneading step.

The invention further relates to alpha crystalline copper phthalocyanine particles obtainable by the process according to the invention. This embodiment is directed to the use of copper phthalocyanine particles available for the process according to the invention for the preparation of copper phthalocyanine particles exhibiting an epsilon crystal form. It also relates to a filter comprising copper phthalocyanine particles exhibiting an epsilon crystal form obtainable by the process according to the invention.

Instance Example 1 (acid paste β-CuPc and phthaloimidomethyl-CuPc)

20 g of crude copper phthalocyanine and 1 g of copper phthalocyanine substituted with quinone imine methyl (PIM) were added to 200 g of 95 wt% sulfuric acid in a 1 L glass beaker. Further, the resulting mixture was stirred by a stirring impeller (Teflon centrifuge at 300 rpm) at 30 ° C for 2 hours to prepare a suspension or solution of sulfate in sulfuric acid. This suspension or solution was poured into 2 L of water to obtain an α-form copper phthalocyanine, which was then washed twice with distilled water and dried under hot air. After the resulting solid powder was ground, it was confirmed by XRD studies that an almost quantitative α-form copper phthalocyanine was obtained in terms of crystal yield.

Example 2 (acid paste β-CuPc and monosulfonate-CuPc)

Copper phthalocyanine particles exhibiting an alpha crystal form were obtained in the same manner as in Example 1 except that 1 g of monosulfonate-CuPc particles were added instead of the quinone imine methyl-CuPc particles.

Example 3 (acid paste of β-CuPc and monosulfonate- and quinone imine methyl-CuPc particles)

Except for the addition of 0.5 g of monosulfonate-CuPc particles and 0.5 g of quinone imine methyl-CuPc particles instead of 1 g of quinone imine methyl-CuPc particles, the appearance of α was obtained in the same manner as in Example 1. Crystalline copper phthalocyanine particles.

Comparative Example 1 (acid paste only β-CuPc)

Copper phthalocyanine particles exhibiting an alpha crystal form were obtained in the same manner as in Example 1 except that the CuPc derivative was not added. When analyzed by transmission electron microscopy (TEM) of some of the dried samples of copper phthalocyanine particles exhibiting alpha crystal form, they were shown to have an average particle size of greater than 140 μm (Fig. 3).

As shown in the TEM images of Figures 1-3, the average particle size (i.e., about 97 nm) of the α-CuPc particles produced using the methods of the present invention (Examples 1 and 2) was significantly lower than by conventional acids. The average particle size (i.e., greater than 140 μm) of the α-CuPc particles prepared by the paste method (Comparative Example 1). By reducing the size of the α-CuPc particles to be kneaded, the kneading time can be remarkably reduced, and the dispersibility of the resulting particles can be improved.

Example 4 (transformation of copper phthalocyanine from crystal form of α crystal form to epsilon crystal form)

To a laboratory-grade kneader, 50 g of copper phthalocyanine particles derived from Example 1 or 2 and an α crystal form and 12 g of ε-type copper phthalocyanine were added together with 80 g of diethylene glycol and 400 g of sodium chloride. The mixture was kneaded at 130 ° C for 2 hours at a rotational speed of 50 rpm (first stage) and then kneaded at 80 ° C for 8 hours at the same rotational speed (second stage). After kneading, the obtained granules were purified by filtration and dried at a temperature of 80 ° C and a pressure of 10 ⁴ Pa.

Example 5 (transformation of copper phthalocyanine from the alpha crystal form to the crystal form of the epsilon crystal form in the presence of monosulfonate-CuPc)

Copper phthalocyanine particles exhibiting an epsilon crystal form were obtained from α-CuPc (obtained from Example 3) in the same manner as in Example 4. However, before the kneading step, the α-form copper phthalocyanine and the ε-type copper phthalocyanine were treated in diethylene glycol at 130 ° C for 2 hours (instead of the first stage) and 6.2 g of MS- was added during the kneading step. CuPc.

Example 6 (transformation of copper phthalocyanine from the alpha crystal form to the crystal form of the epsilon crystal form in the presence of monosulfonate-CuPc)

Copper phthalocyanine particles exhibiting an epsilon crystal form were obtained from α-CuPc (obtained from Example 1) in the same manner as in Example 4. However, before the kneading step, the α-form copper phthalocyanine and the ε-type copper phthalocyanine were treated in diethylene glycol at 130 ° C for 2 hours (instead of the first stage) and 6.2 g of MS- was added during the kneading step. CuPc.

Example 7 (transformation of copper phthalocyanine from the alpha crystal form to the crystal form of the epsilon crystal form in the presence of monosulfonate-CuPc)

Copper phthalocyanine particles exhibiting an epsilon crystal form were obtained from α-CuPc (obtained from Example 1) in the same manner as in Example 4 except that 6.2 g of MS-CuPc was added during the kneading step.

Example 8 (transformation of copper phthalocyanine from the crystal form of the α crystal form to the crystal form of the epsilon crystal form in the presence of cetyltrimethyl ammonium monosulfo CuPc)

A ruthenium exhibiting an epsilon crystal form was obtained from α-CuPc (obtained from Example 1) in the same manner as in Example 4 except that 6.2 g of cetyltrimethylammonium monosulfoCuPc was added during the kneading step. Cyanite particles.

Comparative Example 2 (transformation of copper phthalocyanine from crystal form of α crystal form to epsilon crystal form when PIM-CuPc and MS-CuPc were added)

Copper phthalocyanine particles exhibiting an epsilon crystal form were obtained from α-CuPc (obtained from Comparative Example 1) in the same manner as in Example 4 except that PIM-CuPc and MS-CuPc were sequentially added during the kneading step.

Example 9. Test of particles in a filter

A filter was produced using the ε-shaped copper phthalocyanine pigment particles prepared according to Examples 4 to 8 and Comparative Example 2 as a pigment. The contrast ratio and brightness of the resulting filters are summarized in Table 1 below. These results show that Examples 4 to 8 produced an improvement of about 4% to 21% in the contrast ratio as compared with the contrast ratio of Comparative Example 2, as shown in Table 1. In addition, when a filter was prepared from Example 5 in which PIM-CuPc and MS-CuPc were added in the acid paste step, and MS-CuPc was further added in the kneading step, and Example 6 (in which the acid paste was used) In the step of adding only PIM-CuPc, and further adding MS-CuPc in the kneading step, they produced better effects in contrast ratio and brightness. The filter made from Example 7 (using MS-CuPc) also produced an improved effect compared to Example 8 (using cetyltrimethylammonium monosulfoCuPc).

Industrial application

It will be apparent to those skilled in the art that various modifications and changes can be made in the present invention without departing from the spirit and scope of the invention. Thus, it is intended that the present invention cover the modifications and

In the event that any of the patents, patent applications, and publications disclosed herein are inconsistent with the disclosure, the disclosure is intended to be preferred.

1 is an image from a transmission electron microscope (TEM) of copper phthalocyanine particles exhibiting an alpha crystal phase prepared by the method according to Example 1.

2 is an image from TEM for copper phthalocyanine particles exhibiting an alpha crystalline phase prepared by the method according to Example 2.

3 is an image from TEM for copper phthalocyanine particles exhibiting an α crystal phase prepared by the method according to Comparative Example 1.

Claims (6)

A method for preparing copper phthalocyanine (CuPc) particles exhibiting an epsilon crystal form, comprising: copper phthalocyanine particles, wherein more than or equal to 50% by weight of the particles exhibit an alpha crystal form, and kneaded under a certain temperature condition, thereby A temperature characteristic curve of a function of time shows that the derivative of at least two temperatures with respect to time (dT/dt) is equal to 0, and the at least two temperatures associated with the at least two derivatives equal to 0 differ by at least 10 ° C, wherein: In the presence of a liquid and at least one inorganic salt; the copper phthalocyanine particles exhibiting an alpha crystal form are prepared in the following manner, comprising: (a) a crude copper phthalocyanine particle comprising at least 50% by weight of the particles presenting a beta crystal form Blending with an acid in the presence of CuPc particles substituted with at least one functional group such that at least a portion of the crude CuPc is dissolved in the acid; and (b) precipitating at least a portion of the dissolved CuPc in a medium; Further adding to the CuPc particles substituted by the at least one functional group in the step (a) during the kneading step, including Substituted CuPc particles or CuPc particles substituted with -SO ₃ H. The method of claim 1, wherein the acid is at least one selected from the group consisting of sulfuric acid, chlorosulfonic acid, and polyphosphoric acid. The method of claim 1 or 2, wherein the medium is at least one selected from the group consisting of water, an organic solvent, or a mixture thereof. The method of claim 1 or 2, wherein the average number of functional groups per CuPc molecule is 0.5 to 2. The method of claim 1 or 2, wherein the CuPc particles substituted by one functional group in the step (a) are CuPc particles substituted with -SO ₃ H and A mixture of substituted CuPc particles. A filter comprising copper phthalocyanine particles exhibiting an epsilon crystal form obtainable by the method of any one of claims 1 to 5.