JP2003335997A - Method for producing copper phthalocyanine pigment composition for printing ink and method for producing printing ink - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a copper phthalocyanine pigment composition for printing ink, having a greenish clear color, easily dispersible in a varnish for printing ink, economically advantageous from industrial viewpoint and having high safety and provide a printing ink containing the pigment composition. <P>SOLUTION: The copper phthalocyanine pigment composition for printing ink is produced by crushing crude copper phthalocyanine in dry state together with a resin for printing ink having a softening point of ≥165°C. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing a copper phthalocyanine pigment composition for printing ink and a method for producing printing ink.

[0002]

2. Description of the Related Art There is known a method for directly producing a printing ink by dry-milling a crude copper phthalocyanine and then directly heat-treating it in a printing ink resin and a printing ink solvent.

Although this method is a very effective means for supplying an inexpensive β-type copper phthalocyanine pigment ink,
The pulverized product obtained by dry pulverizing the crude copper phthalocyanine is a very strong aggregate and is a mixture of α-type crystals and β-type crystals and contains a large amount of α-type crystals. Dispersion in water and crystal conversion of α-type crystals to β-type are not smooth with offset printing ink with a small amount of aromatic organic solvent, and it is very difficult in a solvent with a small amount of aromatic components (AF solvent, etc.). is there.

As a technique for improving the above-mentioned drawbacks, Japanese Patent Laid-Open No. Hei 9-90
In JP-A-272833 and JP-A No. 11-35841, a resin for printing ink such as a rosin-modified phenol resin having a softening point of 160 ° C. is added in an amount of 20 to 80% by mass when dry crushing crude copper phthalocyanine. The method is described.

These methods are very effective in that they prevent the aggregation of copper phthalocyanine particles by the effect of the added resin and that the added resin can be the same as the printing ink resin used later. Although a β-type copper phthalocyanine pigment having a ratio close to 1 and a clear hue and a high tinting strength can be obtained, the amount of resin necessary for imparting desired printing ink characteristics is large and the final printing ink is The degree of freedom of the addition amount of various additives such as resins is limited in the adjusting stage.

Further, Japanese Patent Laid-Open No. 2-294365 discloses that
When dry pulverizing the crude copper phthalocyanine, the resin for printing ink such as rosin-modified phenol resin is converted to 0.5 by mass conversion.
A method of adding 0 to 10% is described.

This method can be said to be very effective in that it is similar to the above-mentioned JP-A-9-272833 due to the effect of the added printing ink resin, but the type of printing ink resin used is described. However, it is not suggested what kind of characteristics are preferable. Moreover, the pulverized product after pulverization requires a large amount of energy in the process of forming aggregates in a part and dispersing it in the varnish for printing ink, because the amount of resin required to impart ink properties is small. , Inferior to the conventional dry pigment printing ink manufacturing process.

In any case, in the prior art,
It has not been known at all what properties are suitable as the resin for the printing ink used in the dry pulverization.

[0009]

The problem to be solved by the present invention is that the hue is vivid, the color is easily dispersed in a varnish for printing ink, and it is industrially economical and highly safe. It is intended to provide a copper phthalocyanine pigment composition for printing ink and a printing ink of the pigment composition.

[0010]

Means for Solving the Problems The inventors of the present invention have made earnest studies in view of the above situation, and as a result, dry pulverization of crude copper phthalocyanine in the presence of a resin for printing ink having a softening point higher than that of a conventional one is carried out. The inventors have found that the above problems can be solved, and have completed the present invention.

That is, the present invention provides crude copper phthalocyanine
The present invention relates to a method for producing a copper phthalocyanine pigment composition for printing ink, which comprises dry pulverizing with a resin for printing ink having a softening point of 165 ° C. or higher.

The present invention further relates to a method for producing a printing ink, which comprises mixing the pigment composition obtained by the above-mentioned production method with a solvent for a printing ink and a resin for a printing ink and dispersing the mixture.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below. The pulverized product obtained by dry pulverization in the present invention is a pigment composition consisting only of β-type copper phthalocyanine,
Both a pigment composition containing β-type copper phthalocyanine as a main component and a small amount of α-type copper phthalocyanine are included. The α-type crystal content in the pigment composition can be determined by a known and commonly used method. For example, the peak height at which the peculiar Bragg angle 2θ is 6.8 ° ± 0.2 ° in the diffraction pattern by powder X-ray diffraction analysis. (Lα) and the peak height (Lβ) of 9.2 ° ± 0.2 ° (Lα / Lβ).

The crude copper phthalocyanine used in the present invention is
Any known and conventional one can be used. The manufacturing method is not particularly limited, but the manufacturing method is as follows, for example. (1) Phthalodinitrile and copper and / or a compound thereof,
180 to 300 in an organic solvent or in the absence thereof
The reaction is carried out by heating at 0 ° C under normal pressure or under pressure. (2) 180 to phthalic anhydride and / or a derivative thereof, copper and / or a compound thereof, urea and / or a derivative thereof in the presence of a catalyst, in an organic solvent or in the absence thereof.
The mixture is heated and reacted at 300 ° C. under normal pressure or pressure.

In any of the above cases, for example, when an organic solvent is used, the solvent is distilled off, and in order to remove inorganic and organic impurities, it is dispersed in an alkaline aqueous solution and / or an acidic aqueous solution, filtered and washed. It can be dried and manufactured.

In obtaining the pigment composition of the present invention and a printing ink using the pigment composition, the crude copper phthalocyanine is dispersed in the above alkaline aqueous solution and / or acid aqueous solution to remove impurities, and then filtered. It is preferable to use a highly pure product that has been thoroughly washed with hot water and dried. Among them, as the crude copper phthalocyanine, a purity of 97 to 9 in which both organic and inorganic impurities are removed by washing with an aqueous alkali solution and / or an aqueous acid solution is used.
If 9% of crude copper phthalocyanine is used, the effect of the present invention will be fully exhibited.

The printing ink resin used in the dry pulverization of the present invention is a printing ink resin having a softening point of 165 ° C. or higher. In the present invention, the softening point means a value measured based on ASTM E 28 (ring and ball method) defined by the American Society for Testing and Materials. Examples of the printing ink resin having a softening point of 165 ° C. or higher include rosin-modified phenol resin, rosin-modified maleic acid resin, petroleum resin, and alkyd resin, and these can be used alone or in combination of two or more kinds.

The softening point of the printing ink resin used during dry pulverization may be 165 ° C. or higher, but in particular, it is preferably in the range of 165 to 185 ° C. from the viewpoint of exhibiting excellent dispersibility in an appropriate amount. When a resin for printing ink with a low softening point is used, the internal temperature of the dry crushing device rises above the softening point due to the frictional heat during dry crushing and the resin melts, causing adhesion and sticking phenomenon on the inner wall of the device. There is a risk of inducing ignition due to abnormal heating.

When a rosin-modified resin that does not contain a metal salt as a functional group is used as the resin for the printing ink, the resin for the printing ink coated on the surface of the pigment easily dissolves in the solvent for the printing ink. It is preferable because the progress of dispersion of the particles in the varnish is promoted and the crystal conversion to the β type is easily performed.

Further, in comparison with the rosin-modified resin at the same high softening point, the smaller the acid value of the resin, the higher the solubility of the resin in the solvent for the printing ink and the final printing ink having excellent dispersibility. To be The acid value in the present invention means the number of mg of potassium hydroxide (KOH) necessary to neutralize 1 g of the printing ink resin.

Therefore, the rosin-modified resin has an acid value of 0 to
The rosin-modified resin of 35 is preferable, and of these, the rosin-modified resin having a metal salt as a functional group and an acid value of 0 to 35 is particularly preferable.

As such a resin for printing ink, a rosin-modified resin is preferable, and a rosin-modified phenolic resin is particularly preferable. Examples of the rosin-modified phenol resin include, as a main component, a resin obtained by reacting a rosin with a phenol resin obtained by a condensation reaction of alkylphenol and formaldehyde, and a polyhydric alcohol as a constituent component of the resin. Can be used.
Examples of the alkylphenol that can be used in this case include p-tertiary butylphenol, p-octylphenol, p-nonylphenol and the like.

As such a suitable resin for printing ink, for example, Hariphenol P- manufactured by Harima Kasei Co., Ltd.
222, Hariphenol T3120, Hariphenol P-160, Hariphenol G2900, Hariphenol S-420 and the like.

By using a printing ink resin having such a high softening point as the printing ink resin, the temperature during dry pulverization can be set high, and a dry pulverized product having less α-type crystals can be obtained. This is to increase the productivity of the printing ink per unit time in the step of mixing and dispersing the printing ink solvent and the printing ink resin, which is the step of manufacturing the printing ink, and the energy required for the production. Also leads to reduction.

The addition amount of the resin for printing ink which is dry-ground with the crude copper phthalocyanine is preferably more than 10% and less than 20% in terms of mass with respect to the crude copper phthalocyanine.

When the amount of the resin added is 10% or less with respect to the crude copper phthalocyanine, the dispersibility of the pulverized product and the kneading property as the printing ink when mixed with the solvent for the printing ink, the resin for the printing ink and others. It is not preferable because it tends to deteriorate. On the other hand, when the addition amount of the resin is 20% or more with respect to the crude copper phthalocyanine, the risk of adhesion and sticking of the resin inside the dry crushing device becomes higher. Moreover, the degree of freedom in the amount of addition of various additives such as resins is limited at the stage of adjusting the final printing ink, which is not preferable.

Dry grinding in the production method of the present invention is
Crude copper phthalocyanine is crushed in the presence of crushing media in a dry crusher. That is, this crushing is substantially free of, and not intervening with, a liquid substance. The crushing is performed under the condition that the printing ink resin does not dissolve or melt.

The crude copper phthalocyanine is dry pulverized by adding it to the following dry pulverizer together with the resin for printing ink. The crude copper phthalocyanine and the resin for printing ink may be added to this apparatus, respectively, or the crude copper phthalocyanine and the resin for printing ink may be mixed in advance and this mixture may be added to the dry crushing apparatus described below.

The temperature of the dry pulverization is usually 60 to 180 ° C., and the α-type crystal content of the pulverized product is further lowered to obtain more β.
In order to accelerate the crystal conversion into the mold in a short time, pulverization at a higher temperature is desirable, and it is preferable to carry out at a temperature as high as possible so that the resin for printing ink having a softening point of 165 ° C. or higher does not melt.

The higher the α-type crystal content of the pulverized product is, the more α-type crystals cause the pigment particles to grow like needles during the subsequent crystal conversion into β-type in the presence of the solvent for printing ink. Therefore, the color characteristics of the pigment are not preferable because they cause problems such as deterioration in fluidity and dispersibility in the reddish hue.

Therefore, it is preferable to carry out dry pulverization so that the content of α-type crystals in the pulverized product is reduced as much as possible. The α-type crystal content of the crushed product was fixed to constant crushing conditions except the crushing time including selection of the crushing device to be used, and an appropriate amount of the crushed product was sampled at each crushing time, and the X-ray diffraction A calibration curve of α-type crystal content-milling time can be prepared by measurement and can be determined from it. Specifically, this dry crushing has an α-type crystal content of 35 to 65%.
It is preferable to carry out so as to be within the range.

The dry crushing is preferably carried out so that the crushed product has a primary particle diameter of 0.001 to 0.1 μm. When the primary particle size is within this range, deagglomeration is easily performed by mixing a strong aggregate of primary particles with a solvent for printing ink and a resin for printing ink, and β excellent in coloring power, dispersibility, etc. A printing ink containing a type copper phthalocyanine pigment can be easily obtained.

The dry pulverization can be carried out by utilizing, for example, impact force, shearing force or the like due to collision between the pulverizing media or between the pulverizing media and the inner wall of the pulverizing apparatus. As the dry crushing device, a known and commonly used device such as an attritor, a ball mill, a vibration mill and a hammer mill can be used. As media, beads or rods of various materials and of various sizes can be used.

The dry pulverization can be carried out in the air, but if necessary, an inert gas such as nitrogen gas or helium gas may be circulated in the dry pulverization apparatus so that the inside of the apparatus is in a deoxygenated atmosphere. You may go. This method is also effective in terms of safety.

The pulverization time during the dry pulverization depends on the pulverization temperature and the apparatus used, or the desired particle size of the pulverized product, the pigment composition comprising the pulverized product after the dry pulverization, or the final printing ink using the pigment composition. It is appropriately adjusted according to the target ink characteristics. This crushing time is usually 30 minutes to 5 hours at the above-mentioned crushing temperature.

During the dry pulverization, if necessary, a copper phthalocyanine pigment derivative may be used together with the printing ink resin. Such a copper phthalocyanine pigment derivative has, for example, a substituent on one or more of four benzene nuclei of copper phthalocyanine, and examples of the substituent include a halogen atom, a sulfonic acid group, a carboxylic acid group or a metal salt thereof, Examples thereof include salts with ammonium salts and cationic surfactants, and also various derivatives having a methylene group, a carbonyl group, a sulfonyl group, an imino group or the like.
The amount of the copper phthalocyanine pigment derivative used is not particularly limited, but is 0.1 to 20 parts per 100 parts by mass of the crude copper phthalocyanine.

The pigment composition composed of the pulverized product thus obtained is completely crystallized into β type by mixing with a solvent for printing ink and a resin for printing ink and dispersion treatment to obtain a printing ink easily. be able to.

In the production method of the present invention, since the pulverized product obtained by dry pulverization in the presence of the resin for printing ink is used as the pigment composition, the pulverized product of copper phthalocyanine in the process of preparing the printing ink is crystallized into β type. Conversion is easier.
Since the resin in the pigment composition is dissolved in the solvent for the printing ink to promote the dispersion of the pigment particles, even if the dispersion treatment is performed in the solvent for the printing ink containing no aromatic component, for example, Crystallization of copper phthalocyanine to β type is possible.

Examples of the solvent for the printing ink at this time include high boiling point petroleum solvents, aliphatic hydrocarbon solvents, aromatic hydrocarbon solvents, higher alcohol solvents, and the like. Specific examples include n-paraffin. , Isoparaffin, aromatic, naphthene, α-olefin and the like. These may be used alone or in any combination of two or more.

As a solvent for printing ink, an aromatic compound component is 1% by mass or less, preferably 0.5% by mass, in an aliphatic hydrocarbon such as a naphthene-based component or a paraffin-based component, in that it is less affected by environmental load. % Or less organic solvent can be used as a suitable solvent for printing ink. The content of the aromatic compound can be estimated by, for example, the aniline point.
The printing ink solvent preferably used in the present invention has an aniline point of 65 to 100 ° C.

As such a solvent for printing ink, for example, AF Solvent No. 4 (content of aromatic component: 0.1% by mass) manufactured by Nippon Oil Co., Ltd., AF Solvent No. 5 (No.
2% by mass), AF Solvent 6 (0.2% by mass),
AF solvent No. 7 (same as 0.3% by mass) and the like can be mentioned.

As the printing ink resin used when preparing the printing ink, there are used rosin-modified phenol resin, rosin-modified maleic acid resin, petroleum resin, in addition to the printing ink resin having a softening point of 165 ° C. or higher which can be used in dry pulverization. Examples thereof include alkyd resins and resins such as drying oil modified resins. However, as the resin for the printing ink used when preparing the printing ink, it is preferable to use a resin having excellent compatibility with the resin used during the dry pulverization. The printing ink resin used in preparing the printing ink is selected so that the mixture of the resin and the printing ink resin used in the dry pulverization has excellent fixability to the printed material when used as the printing ink. It

Various kinds of printing ink varnishes are commercially available as a mixture containing a printing ink solvent and a printing ink resin as essential components. In the present invention, this commercially available printing ink varnish may be used, or a printing ink varnish may be prepared by mixing a printing ink solvent and a printing ink resin in advance. It is also possible to simultaneously mix and disperse the pigment composition consisting of the pulverized product, the solvent for printing ink, and the resin for printing ink.

For the purpose of reducing volatile organic compounds as much as possible, the printing ink solvent may be used in combination with a drying oil such as linseed oil, tung oil or soybean oil, or a vegetable oil such as a semi-drying oil. If necessary, a non-drying oil can be used in combination with the drying oil or the semi-drying oil.

When preparing the printing ink varnish, the mixing ratio of the resin for printing ink, the vegetable oil and the solvent for printing ink is
In terms of mass, resin: vegetable oil: solvent = 20 to 50 parts: 0
30 parts: The range of 10 to 60 parts is preferable.

The conditions for mixing and dispersing the pigment composition consisting of the pulverized product obtained by dry pulverization, the printing ink solvent and the printing ink resin are not particularly limited, but the above pigment composition is used. In order to achieve complete crystal conversion of the copper phthalocyanine into the β-form and stable dispersion in the product, it is preferable to carry out, for example, at 60 to 180 ° C. for 10 minutes to 4 hours.

In the method for producing a printing ink of the present invention, the above-mentioned printing ink resin and printing ink are used so that the pigment concentration required for the printing ink finally used (referred to as the final printing ink) is obtained. The final printing ink may be prepared in one step using a solvent, or a concentrated printing ink with a higher pigment concentration than the final printing ink (referred to as premix ink) may be prepared in advance and then printed with a printing ink resin. The final printing ink may be prepared in multiple stages by diluting with an ink solvent.

For this dispersion treatment, a known disperser or the like is used. As the disperser used for kneading, any of known dispersers may be used, and examples thereof include known dispersers such as a disper, a homomixer, a bead mill, a ball mill, a bead mill, a two roll, a three roll and a kneader. To be Of course, these may be used in combination.

In the method for producing the printing ink of the present invention, since the surface of the copper phthalocyanine is coated with the resin for the printing ink in the step of producing the pigment composition in the first stage, this dispersion according to the method for producing the printing ink in the second stage is performed. The treatment can be performed by kneading with gentler stirring than in the past. Therefore, in the above-mentioned disperser, this dispersal treatment can be carried out even by a disperser kneading with a weak stress. However, if it is desired to shorten the dispersion time, it is possible to further shorten the time by carrying out dispersion processing using a disperser in which kneading is performed with a strong stress.

In the case where the final printing ink is prepared through a multi-step process, the premix ink is obtained as described above, and the resin for printing ink and the solvent for printing ink are further used in combination to prepare 10 The final printing ink can be obtained by kneading the meat with a two-roll or three-roll roll at -60 ° C 1 to 5 times.

In the method for producing a printing ink of the present invention, various additives such as a curing accelerator (dryer) and a release agent (wax) for the resin for the printing ink may be included in any step of the method. Can be done.

Thus, in the present invention, a printing ink can be directly produced from a dry pulverized product of crude copper phthalocyanine without going through the form of powder of the β-type copper phthalocyanine pigment.

[0053]

EXAMPLES The present invention will be described in detail below with reference to production examples, examples and comparative examples. Unless otherwise specified, "%" and "parts" are based on mass.

In the following, as the printing ink varnish of this example, 47% of a commercially available rosin-modified phenolic resin, which is different from that used in dry pulverization but has excellent compatibility with it, AF Solvent No. 7 (manufactured by Nippon Oil Co., Ltd.) The one composed of 47% and linseed oil 6% was used.

[Production Example 1] (Production of Crude Copper Phthalocyanine) 1218 parts of phthalic anhydride, 1540 parts of urea, 200 parts of anhydrous cuprous chloride, 5 parts of ammonium molybdate, and an alkyl having 5 to 8 carbon atoms as a solvent. 4000 parts of a mixture of alkylbenzene having a group was charged into a reactor, heated with stirring to raise the temperature to 200 ° C., and then reacted at the same temperature for 2.5 hours. After completion of the reaction, the solvent was distilled off under reduced pressure, the remaining reaction product was added to 8000 parts of a 2% aqueous sodium hydroxide solution, the mixture was stirred at 70 ° C. for 1 hour, and suction filtered to obtain a cake. Then, the cake obtained is 2
% Hydrochloric acid (aqueous solution), and the mixture was stirred at 70 ° C. for 1 hour, neutralized, and suction filtered. The cake thus obtained was thoroughly washed with warm water at 80 ° C. and then dried to obtain crude copper phthalocyanine (purity 98%).

[Example 1] (Production of copper phthalocyanine dry pulverized product and final printing ink) 500 parts of the above-mentioned crude copper phthalocyanine and "Hariphenol P-222" (Harima Kasei Co., Ltd., rosin-modified phenol resin, softened) Point 172 ° C., acid value 22.1, weight average molecular weight Mw = 10459. 75 parts of an attritor having an internal volume of 5 liters (13 kg of a steel ball having a diameter of 3/8 inch) is used. Rotation speed 300 rpm, internal temperature 90-110
Crushing was performed at 60 ° C. for 60 minutes to obtain 568 parts of a dry crushed product. This pulverized product contains 59% α-type crystals of copper phthalocyanine and β
It was composed of 41% of the mold crystals. In addition, this α
Type crystal content is powder X-ray diffractometer manufactured by Rigaku Corporation
Using LINT1100, Japanese Patent Application Laid-Open No. 10-101955
According to the method described in the publication, Lα / Lβ was determined and determined (the same applies hereinafter). Next, 175 parts of this pulverized product, 230 parts of the above printing ink varnish and 95 parts of AF Solvent No. 7 were added and stirred at 120 ° C. for 2 hours to obtain a premix ink. Further, 19 parts of the above printing ink varnish and 4 parts of AF Solvent No. 7 were added to 27 parts of the obtained premix ink, stirred and adjusted, and then kneaded twice with a three-roll roller at 40 ° C. to obtain a final printing ink. .

[Example 2] (Production of copper phthalocyanine dry pulverized product and production of final printing ink) Instead of "Hariphenol P-222", "Hariphenol T3120" (Harima Kasei Co., Ltd., rosin-modified phenol resin) , Softening point 170 ° C., acid value 30.4,
Weight average molecular weight Mw = 65,000. Does not have a functional group consisting of a metal salt. Was carried out in the same manner as in Example 1 except that) was used to obtain 565 parts of dry pulverized product. The pulverized product was composed of 52% of α-type crystals of copper phthalocyanine and 48% of β-type crystals. Using this pulverized product, the same operations as in Example 1 were performed to obtain the final printing ink.

[Comparative Example 1] (Production of copper phthalocyanine dry pulverized product and production of final printing ink) Instead of "Hariphenol P-222", "Hariphenol 145G" (Harima Kasei Co., Ltd., rosin-modified phenol resin) The same operation as in Example 1 was carried out except using a softening point of 147 ° C. and an acid value of 12.7) to obtain 566 parts of dry pulverized product. This pulverized product was composed of 63% of α-type crystals of copper phthalocyanine and 37% of β-type crystals. Using this pulverized product, the same operations as in Example 1 were performed to obtain the final printing ink.

[Comparative Example 2] (Production of copper phthalocyanine dry pulverized product and production of final printing ink) Instead of "Hariphenol P-222", "Harimac R-120AH" (Harima Kasei Co., Ltd., rosin modified malein) Acid resin, softening point 118 ° C, acid value 25.7)
The same operation as in Example 1 was carried out except that was used to obtain 547 parts of dry pulverized product. The pulverized product was composed of 67% of α-type crystals of copper phthalocyanine and 33% of β-type crystals. Using this pulverized product, the same operation as in the following examples was performed to obtain the final printing ink.

[Test Example] << Lithographic ink spread test >> This test method is based on JIS K-51.
01-4 According to the Ko method (1985). (Dark Color Ink) The final printing inks obtained in Examples 1 and 2 and Comparative Examples 1 and 2 were used as they were as dark color inks.

(Light color ink) 0.20 parts of the above dark color ink and 4.00 parts of white ink (New Champion AT White 179 [white pigment 30 manufactured by Dainippon Ink and Chemicals, Inc.]
%]) Was subjected to kneading by repeating 50 times under a load of 50 lbs using a Hoover Mahler to prepare a lithographic printing ink (light color ink).

<< Evaluation Criteria for Hue, Saturation, and Dispersibility >> Hue, Saturation: The light-colored ink prepared in the above test is spread on a general color-developing paper with a spatula, and the upper color (flesh color) is measured with a colorimeter. (SPM50 manufactured by GRETAG MACBETH). Hue is h value, Saturation is C * value (L * a *
The performance of the final printing inks of Examples 1 and 2 and Comparative Examples 1 and 2 was evaluated using (b * display color system) as an index.

The hue is indicated by the hue angle h. It means that the smaller the h value, the more green the hue is. Saturation is indicated by C *. The larger the C * value, the sharper the image.

Dispersibility: A small amount of the dark ink of the above test was rubbed on a glass plate and observed with an optical microscope (TMM-100D manufactured by TOPCON Co., Ltd.) at a magnification of 100 times, and a large number of large pigment particles were observed. Those having poor dispersibility were judged to have good dispersibility when the particles were fine or the particles were difficult to see. In the table below, those having very good dispersibility are indicated by ◯, those having good dispersibility are indicated by Δ, and those having poor dispersibility are indicated by x.

Table 1 shows the measurement results concerning the hue, saturation and dispersibility of the final printing inks of Examples 1 and 2 and Comparative Examples 1 and 2.

[0066]

[Table 1] Table 1

As is clear from the results in Table 1, the final printing inks obtained from the copper phthalocyanine pulverized products of Examples 1 and 2 obtained by dry pulverization in the presence of a printing ink resin having a high softening point were: As a result of comparison with the final printing ink obtained from the pulverized products of Comparative Examples 1 and 2 obtained by similarly dry pulverizing using a conventional resin for printing ink having a low softening point, the hue is vivid and excellent. It can be seen that it has excellent dispersibility.

[0068]

According to the production method of the present invention, by subjecting crude copper phthalocyanine to dry pulverization together with a resin for printing ink having a high softening point, finer and excessive aggregation suitable for the preparation of printing ink is achieved. Thus, primary particles of copper phthalocyanine having the above-mentioned properties can be obtained. As a result, the solubility of the resin in the solvent is high at the stage of preparing the printing ink, and because of easy dispersion, the crystal conversion to β type becomes smooth in any solvent system,
A final printing ink having a clearer hue and excellent dispersibility can be easily obtained.

Furthermore, since a resin for printing ink having a high softening point is used, it is safe that it does not adhere in the apparatus during dry pulverization, and the amount of resin added is in the optimum range. There is a wide range of tolerances that give the characteristics of the individual purpose required. Further, a printing ink can be directly produced from crude copper phthalocyanine without going through the form of producing only a pigment once, which is excellent in industrial and productivity.

That is, the present invention exerts a particularly remarkable effect that a copper phthalocyanine pigment composition for a printing ink and a printing ink having a clear hue with a greenish hue, easy dispersion and high safety can be produced more easily than the conventional method.

Claims (5)

[Claims] 1. A crude copper phthalocyanine having a softening point of 16
A method for producing a copper phthalocyanine pigment composition for a printing ink, which comprises dry-milling with a resin for a printing ink at 5 ° C or higher. 2. The production method according to claim 1, wherein the resin for printing ink is a rosin-modified resin having no metal salt as a functional group. 3. The method according to claim 1, wherein the printing ink resin is a rosin-modified resin having no metal salt as a functional group, and the resin has an acid value of 0 to 35. 4. The production method according to claim 1, wherein the amount of the printing ink resin added is more than 10% and less than 20% in terms of mass with respect to the crude copper phthalocyanine. 5. A method for producing a printing ink, which comprises mixing the pigment composition obtained by the method according to claim 1, 2, 3 or 4 with a solvent for the printing ink and a resin for the printing ink and subjecting the mixture to a dispersion treatment.