MXPA97002997A - Process for preparation of pigment composition, pigment composition and its - Google Patents

Abstract

In accordance with the present invention, a resin is added to a crude copper phthalocyanine comprising crystals of an alpha form and a beta form in combination, and dry grinding is carried out in a deoxygenated atmosphere, to provide a composition of superior copper phthalocyanine pigment that reduces the considerable time and labor expense associated with the pigment process of the crude copper phthalocyanine, and the printing ink production process comprising the copper phthalocyanine pigment of beta form, super quality

Description

- "PROCESS FOR PREPARATION OF COMPOSITION OF PIGMENT, COMPOSITION OF PIGMENT AND ITS USE" BACKGROUND OF THE INVENTION FIELD OF THE INVENTION The present invention relates to a process for preparing a copper phthalocyanine pigment composition of beta form from crude copper phthalocyanine, and to the pigment composition and its use. More specifically, the present invention relates to a process for preparing a copper phthalocyanine pigment of beta form by treating the crude copper phthalocyanine with a printing ink resin or a printing ink resin containing a solvent, a the pigment composition itself and the process for preparing the printing ink from this composition.

DESCRIPTION OF THE PREVIOUS TECHNIQUE The production of printing ink containing a pigment, usually requires the following two processes: The first process is known as the pigmentation process. Copper phthalocyanine, as synthesized, is called crude copper phthalocyanine and is not suitable as a printing ink pigment without additional treatment, since its beta-shaped glass particles have large diameters within the 10-fold scale. at 200 micrometers. The process to reduce the particle size of this crude copper phthalocyanine to a size (from 0.02 to 0.1 micrometer) appropriate for printing ink is called pigmentation. The technique is known various methods for pigmentation. The most commonly employed method is called the solvent salt grinding method. This method involves adding to the crude copper phthalocyanine a combination of the grinding agent such as sodium chloride and organic solvents that activate the transformation of the crystal into the beta form and then carry out the grinding process. The beta-form copper phthalocyanine pigment obtained by this method has an elongation (ratio of primary diameter to secondary diameter of a primary particle) of 1 to 3, is appropriate for printing ink due to its greenish tone, cla and high strength to color and therefore it is widely used. In this method, however, the amount of milling agent that is required is several times greater than that of the pigment and a considerable amount of time, labor and energy are invested to recover the milling agent and the organic solvents. Another conventional method involves dry milling of crude copper phthalocyanine before it is treated with an organic solvent or other chemical substances. In this method a part of the beta-shaped crystal undergoes transformation to the alpha form as a result of mechanical stress during grinding. To restore the beta form, therefore, the ground material must undergo thermal treatment with an organic solvent. Although this method has a cost advantage in relation to the solvent salt milling method, there are some problems such as a large particle ratio as a consequence of its acicular growth during heat treatment with an organic solvent, resulting in a reddish tone and inadequate fluidity of the product. There is a method to suppress this growth of particles by adding pigment derivatives and growth inhibitors. These additives, however, are often not desirable as components of the printing ink. The second process is known as an ink manufacturing process. Generally, there are two methods for preparing the printing ink from a pigment, one employing a dry pigment and the other a wet cake pigment usually containing 40 percent to 70 percent water. The method of making ink using a dry pigment is one in which a dry pigment is first mixed with a varnish of the printing ink, the solvent and other additives and then the pigment is dispersed by a device such as a bead mill or a three-cylinder mill. Since the primary particles of the dry pigment have an intense tendency to agglomerate, a considerable amount of energy is invested in an effort to disperse the pygmy. The method using a wet cake pigment is called the washing method. It is a method in which the wet cake pigment is mixed with a varnish of the printing ink, the solvent and other additives to change the phase of the pigment from the water phase to the varnish phase. Although this method does not require energy as opposed to the dry ink manufacturing process, a large-scale apparatus such as a kneader is required and discharges the water produced by the washing process, which imposes some difficulty. As described in the previous section, both the pigmentation process and the ink manufacturing process require the investment of considerable time and energy for the preparation of the printing ink containing the copper phthalocyanine form beta. To provide printing ink at low cost, therefore, it would be desirable and efficient to produce the ink directly from the raw copper phthalocyanine without having to go through the handling of the pigments. A method is known in which crude copper phthalocyanine is mixed with the printing ink varnish and both pigmentation and ink manufacturing processes are simultaneously achieved in a bead mill. However, since the pigmentation process in the printing ink varnish has low milling efficiency, it requires the use of a dipserion mill with ultrafine beads and therefore, one has to face problems associated with energy efficiency and the quality of the final product. The publication of the Patent Application Japanese Number (JP-B) 55-6670 proposes a method in which crude copper phthalocyanine is first ground dry and then ink is produced without additional steps. Even when dry milling is an effective method since it is inherently efficient, the milled material obtained in this way is a mixture of crystals of alpha form and beta form. The crystal of alpha form in the mixture must then be converted to the beta form in the ink. Shape transformation from the alpha form to the beta form advances in the presence of heat and organic solvents and / or effectively continues in gravure ink that is rich in aromatic organic solvents. It is not effective, however, in "offset" printing ink where it contains only a small amount of the solvent. The transformation to the beta form is very difficult in solvents that do not contain an aromatic compound (the AF solvent) that are becoming increasingly popular. In this regard, it is known that the reduction of agglomeration of ground copper phthalocyanine is an effective means to achieve the ink manufacture of this milled material efficiently. Several methods have been proposed. For example, British Patent Number 1224627 proposes a method in which the dry milling of crude copper phthalocyanine, a part is achieved with the addition of 1 to 8 parts of resin. Japanese Patent Specification Number (JP-A) 2-294365 proposes a method in which 0.5 percent to 10 percent resin is added, such as a rosin-modified phenolic resin for the dry milling of the phthalocyanine raw copper. These methods are effective in preventing the agglomeration of copper phthalocyanine particles in the presence of the added resin. The phenol resin modified with rosin, however, is known due to its tendency to degrade by oxidation even when maintained at room temperature. For the methods proposed in these patents, it is still impossible under cooling to prevent the oxidation of the resin additives during grinding, since grinding causes increases in the surface area and the collision shock generates thermal hooks. Since oxidation changes the solubility, color tone and other properties of resins, the selection of resins conventionally used for this purpose can not yield products with characteristics comparable to conventional ink. In addition, the primary particles of the ink obtained by these methods are characterized by their acicular configuration unlike those obtained by the solvent salt milling method. In this way, the problems of reddish hue and fluidity are not solved. There is a known method to suppress this growth of the particle. Involves the addition of pigment derivatives and growth inhibitors. These additives, however, are often not desirable as the components of the final printing ink.

SUMMARY OF THE INVENTION The object of the present invention is to provide a high quality copper phthalocyanine pigment composition that reduces the considerable time and labor associated with the pigmentation process of crude copper phthalocyanine and the production process of printing ink of a pigment, and to provide printing ink containing a copper phthalocyanine pigment of beta form of superior quality. The present invention provides a method for preparing a pigment composition, wherein crude copper phthalocyanine is added to the resin, and dry-milled in a deoxygenated atmosphere. As a means to carry out dry milling in the deoxygenated atmosphere, the interior of a dry mill can be filled with an inert gas. This is usually achieved by flowing nitrogen gas. A completely oxygen-free environment is not required. Under some conditions of dry milling, it is sufficient to only reduce the oxygen concentration to a desired level. The present invention further provides a method for preparing a pigment composition as described above, wherein the resin referred to above is a phenol resin modified with rosin. The preferred resins to be added to the crude copper phthalocyanine are those resins used in the printing ink, such as the rosin-modified phenol resin, the rosin-modified maleic acid resin, the petroleum resin and the alkyd resin . Each can be used by itself or in combination with two or more of them. These resins are very effective to activate the transformation of form from a crystal of alpha form to beta form of crude copper phthalocyanine. The present invention further provides a method for preparing the aforementioned pigment composition, wherein the amount of the resin to be added is from 1 percent to 200 percent by weight of the crude copper phthalocyanine. When an excessive amount of the resin is added to the raw copper phthalocyanine, there is a considerable risk of causing adhesion and bonding of the resin inside the dry grinding apparatus. Since this phenomenon is influenced in part by the softening temperature of the resin and by the milling temperature, the amount of resin to be added has been brought to the optimum as specified above. The present invention further provides a method for preparing the aforementioned pigment composition wherein the amount of resin to be added is from 5 percent to 100 percent by weight of the crude copper phthalocyanine. This scale is the result of more specifically adjusting the softening temperatures of commonly used resins. The present invention further provides a method for preparing the aforementioned pigment composition by dry grinding at a temperature between 60 ° C and 200 ° C. Since the phthalocyanine copper component of alpha form of crude copper phthalocyanine is converted to a copper phthalocyanine beta form when heated, dry grinding is carried out at relatively high temperatures to reduce the fraction of the form alpha. On the other hand, since grinding at too high a temperature detrimentally affects the copper phthalocyanine pigment, the dry milling of the present invention is carried out at a temperature within 60 ° and 200 ° C. The present invention further provides a method for preparing the aforementioned pigment composition by dry milling at a temperature between 80 ° C and 170 ° C. This temperature scale is preferred taking into account the two competing factors, ie the detrimental effect of oxidation and the activation of the shape transformation.

The present invention further provides a method for preparing the aforementioned pigment composition wherein the solvent is added to the resin in an amount ranging from 0.5 percent to 20 percent by weight of the resin. The present invention further provides a method for preparing the aforementioned pigment composition in which a resin containing a solvent is used. The present invention further provides a method for preparing the aforementioned pigment composition in which the solvent is a printing ink solvent. The resin and the organic solvent can be added separately or the solvent can be mixed in the resin before being added to the pigment. The present invention provides a pigment composition obtained by the aforementioned method for preparing a pigment composition. The present invention provides a pigment composition obtained by adding a resin to the crude copper phthalocyanine, and achieving dry milling in a deoxygenated atmosphere or an atmosphere having an inert gas. The present invention further provides a pigment composition in which the aforementioned resin is a phenol resin modified with rosin. The present invention provides a pigment composition in which the amount of the aforementioned resin to be added is from 1 percent to 200 percent by weight of the aforementioned crude copper phthalocyanine. The present invention provides a pigment composition in which the amount of the aforementioned resin to be added is from 5 percent to 100 percent by weight of the aforementioned crude copper phthalocyanine. The present invention provides a pigment composition in which the temperature of an atmosphere for dry milling is between 60 ° C and 200 ° C. The present invention provides a pigment composition in which the temperature of an atmosphere for dry milling is between 80 ° C and 170 ° C. The present invention is a pigment composition in which a solvent in an amount ranging from 0.5 percent to 20 percent by weight of the aforementioned resin is added to the aforementioned crude copper phthalocyanine to which is added the above-mentioned resin. The present invention in a pigment composition in which a solvent is first added to the resin in an amount ranging from 0.5 weight percent to 20 weight percent of the aforementioned resin, which is then added to the phthalocyanine raw copper previously mentioned.

The present invention further provides a pigment composition in which the aforementioned solvent is a printing ink solvent. It provides a superior copper phthalocyanine pigment composition that reduces the considerable time and labor required to prepare copper phthalocyanine for printing ink. The present invention further provides a method for preparing the printing ink wherein the aforementioned pigment composition is first added to a solvent or varnish of the printing ink and then the mixture is processed. The process disclosed in the present invention considerably simplifies the conventional pigmentation process. Even when the oxidation of the added resin detrimentally affects the performance of the ink in the other similar methods, the resin of the present invention is not degraded and therefore it is possible to prepare the printing ink of the same quality even when the resins used are those used in the prior art. The other objects of the present invention will become more apparent as the modalities that will be described below are understood, and those skilled in the art should be able to easily obtain the advantages to which reference is not explicitly made but which is imply in this exhibition.

DETAILED DESCRIPTION OF THE INVENTION The object of the present invention is to provide a copper phthalocyanine pigment composition of superior quality thereby reducing the time and labor associated with the crude copper phthalocyanine pigmentation process and the "ink production process". printing of the copper phthalocyanine, and providing a printing ink containing a copper phthalocyanine pigment of beta form of superior quality In accordance with the present invention, a resin is added to the crude copper phthalocyanine, and it is dry milling in a deoxygenated atmosphere When the printing ink is conventionally prepared by adding the crude copper phthalocyanine of the dry-ground beta form to an ink solvent or varnish without any previous processing, the ground material exhibits intense agglomeration. As a result, it becomes difficult to disperse the pigment particles with ease and induce form transformation a of the crystal of alpha form in the ground material back to the beta form.

In the present invention, the preferred resins include that which is to be added to the crude copper phthalocyanine in the dry milling, a resin used in the printing ink such as a phenol resin modified with rosin, a resin of maleic acid modified with rosin, petroleum resin and alkyd resin. These can each be used by themselves or in combination of two or more thereof, but the phenol resin modified with rosin is particularly preferred. These resins are effective for dispersing the ground material and for activating the crystal transformation from the alpha form to the beta form. When an excessive amount of resin is added, there is a risk of causing adhesion and bonding of the resin inside the dry mill. This is naturally influenced also by the softening temperature of the resin and by the temperature at which the grinding is carried out. The optimum amount of resin must therefore be determined taking into account these factors. The amount of resin to be added is within the range of 1 percent to 200 percent by weight of crude copper phthalocyanine. The grinding duration is adjustable and is determined by the selection of the apparatus and the desired particle size of the ground material. The dry milling process according to the present invention involves grinding the crude copper phthalocyanine without any presence of a liquid medium using a mill loaded with the milling medium such as beads. The grinding is achieved by grinding force and destructive force that are generated by collision between the elements of the grinding media. Dry milling can be carried out by conventional means known in the art such as a dry grinder, a ball mill and a vibration mill. Dry grinding can be carried out in a deoxygenated environment as needed, by cleaning the inside of the dry grinding apparatus with a flow of nitrogen gas. The dry milling according to the present invention is carried out in a deoxygenated atmosphere to prevent degradation of the resin added during milling and in this way develop attributes designed for the ink. Negative oxidation effects of the added resin include poor solution of the ink in a fountain solution in the case of an "offset" printing ink. This is probably caused by the reduction in the surface tension of the resin by its oxidation. This adversely affects the properties of an offset printing ink. As means for carrying out dry milling in a deoxygenated atmosphere, the interior of the dry mill can be filled with an inert gas. This is most commonly accomplished by introducing a flow of nitrogen gas. A completely oxygen-free environment is not required. Under some conditions of dry milling, it is sufficient only to reduce the oxygen concentration to a desired level. The deoxygenated condition according to the present invention, therefore, should not be understood as the oxygen concentration of less than 10 percent. Reducing oxygen in this way also improves safety. Although crude copper ground phthalocyanine is a mixture of alpha-form and beta-form crystals, a complete conversion to the beta form is required, either in an organic solvent or mixed with a solvent or printing ink varnish. Even though it is possible to select the optimum organic solvent for this purpose and this selection of the printing ink solvent does not require any specific difficulty for the aromatic compound containing the solvent such as the gravure printing ink, it is significantly more difficult to carry the optimum Solvents that do not contain an aromatic compound. In the present invention, however, transformation to the beta form is facilitated by using the treated pigment which has already been dry milled in the presence of a resin. Specifically, since the particle dispersion is accelerated by dissolving the resin treated in the solvent, the transformation to the beta form continues easily even for the printing ink solvents containing an aromatic compound. On the other hand, when the transformation of the crystals from alpha form to beta form takes place in the presence of an organic solvent, some of the particles dissolve and result in the acicular growth of the pigment particles, with undesirable consequences such as tone or reddish hue and poor fluency. It is therefore preferred to restrict the crystal fraction of alpha form in the dry milled material. It is generally known that the transformation of the alpha form to the beta form takes place in the presence of heat and / or an organic solvent. Therefore, a means by which the crystal fraction of alpha form is reduced in dry milling is to carry out dry milling at a relatively high temperature. Since the excessively high temperature detrimentally affects the copper phthalocyanine pigment itself, the dry grinding of the present invention should preferably be carried out at a temperature between 60 ° and 200 ° C.

The addition of an organic solvent is also effective to decrease the crystal fraction of alpha form in dry milling. In the present invention, an organic solvent may also be added together with a resin. Since excessive solvent addition is not recommended for dry milling, the fraction to be added is within the range of 0.5 percent to 20 percent by weight of the resin. In the present invention, when a solvent and a resin are added in the dry milling of crude copper phthalocyanine, a resin and an organic solvent can either be added separately or an organic solvent can be incorporated into the resin beforehand. Organic solvents capable of inducing the transformation of the crystal from alpha to beta form are preferred. Examples of these solvents include aromatic compounds such as toluene, xylene, chlorobenzene and nitrobenzene, aliphatic hydrocarbon compounds such as mineral essence, emesin and ligroin, alcohol compounds such as isopropanol, butanol, isobutanol, ethyl cellosolve, butyl cellosolve and cyclohexanol ester compounds such as ethyl acetate, butyl acetate, and butyl cellosolve acetate, and acetone compounds such as acetone and methylethyl ketone. These compounds can each be used by themselves or in combination of two or more. When printing ink is prepared directly, it is possible to use printing ink solvents that do not require any process for solvent removal. As printing ink solvents, solvents that do not contain an aromatic compound can also be used alone or in combination of two or more as long as they are the appropriate solvents for printing inks such as petroleum type solvents having a high temperature of boiling, aliphatic hydrocarbon solvents and solvent of the higher alcohol type. Since the milled material obtained is a mixture of crystals of alpha form and beta form, all of them must be changed to the beta form by treatment with an organic solvent. There are two methods to achieve this task: one method involves the transformation of the beta form that is carried out in a printing ink solvent followed by the direct preparation of the printing ink and the other involves the conversion to the beta form being treated in one of the aforementioned organic solvents with the capacity to induce transformation to the beta form. When the transformation to the beta form is effected in a printing ink solvent, the transformation is continued to a suitable regime by mild agitation and there is no specific need for any dispersion medium. The dispersion of the ground material and the transformation to the beta form are completed in several tens of minutes up to three hours, depending on the selection of the printing ink solvent. The preparation of the ink base is then completed by passing the material through a simple dispersion machine. The procedure at an elevated temperature increases the efficiency of the beta transformation. When shortened processing time is desired, the use of a conventional dispersing machine such as a bead mill can produce a dramatic reduction in processing time. When the printing ink is to be prepared directly using the pigment composition obtained in the process described in the previous section, solvents not containing an aromatic compound such as the solvents of the printing ink or the solvents in a varnish can also be used. themselves or in combination of two or more as long as they are suitable solvents for a printing ink, such as petroleum type solvents, which have a high boiling temperature, aliphatic hydrocarbon solvents and higher alcohol type solvents.

Similarly, when the printing ink is producedExamples of printing ink varnish resins include resins suitable for printing ink such as phenolic resins modified with rosin, colony-modified maleic acid resins, petroleum resins and alkyd resins. They can be used in combination of a drying oil and a polymerized drying oil compatible with the printing ink such as soybean oil, tung oil and linseed oil and with other additives for the printing ink. Each one can be used by itself or in combination of two or more. On the other hand, when the copper phthalocyanine pigment of beta form is prepared by solvent treatment of the milled material obtained, the solvent treatment is usually carried out in an organic solvent by itself or in a mixture of an organic solvent and water. In the case of the mixture, it is used without any modification when the solvent has great affinity to water. When the solvent has little or no affinity for water, the mixture normally used is emulsified with a surfactant. The aforementioned organic solvent that activates the transformation of the beta form can be used as the organic solvent in this process.

The ink samples produced by these methods were compared with those that were prepared by an ink manufacturing process from a dry pigment obtained by the conventional solvent salt milling method, and with those that were prepared by the process of ink manufacture employing the cleaning method from a wet cake pigment containing water. It was confirmed that the ink produced by the methods of the present invention has quality equivalent to the ink prepared by the solvent salt milling method and by the cleaning method with respect to color, gloss or luster resistance or flowability.

DESCRIPTION OF THE PREFERRED MODALITIES The practical details of the present invention will be described in terms of examples and comparative examples which will be given below: The normal ink referred to in the following examples is the beta-form copper phthalocyanine pigment ink, prepared by the cleaning method using the wet cake pigment obtained from pigmentation of the crude copper phthalocyanine by the solvent salt milling method (5 parts of sodium chloride to a part of the source material). The composition of the varnish used to prepare the ink is 47 percent phenol resin modified with rosin, 47 percent of the printing ink solvent (a solvent identical to that added separately) and 6 percent linseed oil. All ink samples prepared as standard, Examples and Comparison Examples were first adjusted to the same tack value (reading from an ink meter) and then 0.3 cubic centimeters in each case were printed on an art paper (250 x 270 centimeters) using an Rl tester (type RI-2, Hikari Seisakusho K.K.). The color strength was evaluated using a PRESSMATE densitometer model 110 (Koser Corp.) and gloss or luster was evaluated by a digital deformation luster meter (Suga Shikenkisha K.K.). The crystal structure of copper phthalocyanine was determined by an X-ray diffractometer.

[Example 1] A dry grinder was charged with 70 parts by weight of crude copper phthalocyanine and 7 parts by weight of modified phenol resin with rosin having a softening point of 160 ° C. The mixture was milled for one hour at 160 ° C in flowing nitrogen. The resin was extracted from the pigment composition obtained in this manner and the properties of the extracted resin were measured not revealing significant changes compared to those before milling. 18 parts by weight of the resulting milled material were added to 44 parts by weight of a printing ink varnish and 5 parts by weight of solvent NUMBER 7 (Nippon Oil Co., Ltd.). The resulting mixture was stirred slightly for 4 hours at 120 ° C. The mixture was then kneaded by a three cylinder mill at 60 ° C for three passes to yield dispersed pigment particles of a size smaller than 7.5 micrometers. Then 22 parts by weight of a varnish and 11 parts by weight of the solvent NUMBER 7 (Nippon Oil Co., Ltd.) were added to the paste ink obtained in this way to prepare the ink, the final product. It was compared with normal ink containing the same pigment fraction. The ink in the example had qualities equivalent to normal ink in terms of color strength, luster, hue and dispersibility in water. The crystal fraction of alpha form was less than 1 percent.

[Example 2] A dry grinder was charged with 70 parts by weight of the crude copper phthalocyanine and 35 parts by weight of the modified phenol resin with rosin having a softening point of 160 ° C. They were ground for one hour at 130 ° C under nitrogen. The resin was extracted from the pigment composition obtained in this manner and the properties were measured to reveal that there were no significant changes compared to that prior to milling. Then 32 parts by weight of a printing ink varnish and 11 parts by weight of the solvent NUMBER 7 (Nippon Oil Co., Ltd.) to 24 parts by weight of the resulting milled material. The resulting mixture was stirred slightly for 2 hours at 100 ° C. The mixture was then kneaded by a three cylinder mill at 60 ° C in a single pass to yield the dispersed pigment particles of a size of less than 7.5 microns. Then 22 parts by weight of a varnish and 11 parts by weight of the solvent NUMBER 7 (Nippon Oil Co., Ltd.) were added to the grass ink obtained in this way to prepare the ink, the final product. It was compared with normal ink containing the same pigment fraction. The ink of the example had qualities equivalent to normal ink in strength or firmness of color, luster, hue and water dispersibility. The crystal fraction of alpha form was less than 1 percent.

[Example 3] A dry mill was charged with 70 parts by weight of crude copper phthalocyanine and 70 parts by weight of phenol resin modified with rosin having a softening temperature of 160 ° C. The mixture was milled for one hour at 80 ° C in flowing nitrogen. The resin was extracted from the pigment composition obtained in this manner and its properties were measured to reveal that there were no significant changes compared to those before the treatment. Then 16 parts by weight of the printing ink varnish and 19 parts by weight of solvent NUMBER 7 (Nippon Oil Co., Ltd.) were added to 32 parts by weight of the ground material obtained in this way. The resulting mixture was stirred slightly for 2 hours at 100 ° C. The mixture was then kneaded by a three cylinder mill at 60 ° C in a single pass to yield dispersed pigment particles of a size less than 7.5 microns. 22 parts by weight of a varnish and 11 parts by weight of the solvent NUMBER 7 (Nippon Oil Co., Ltd.) were added to the resulting paste ink to prepare the ink, the final product. It was compared with normal ink containing the same pigment fraction. The ink in the example had qualities equivalent to normal ink in color fastness, luster and water dispersibility. The crystal fraction of alpha form was less than 1 percent.

[Comparison Example 1] A dry grinder was charged with 70 parts by weight of crude copper phthalocyanine and the filler was ground for one hour at 130 ° C in air. Then 48 parts by weight of the printing ink varnish and 3 parts by weight of the solvent NUMBER 7 (Nippon Oil Co., Ltd.) were added to 16 parts by weight of the resulting ground material. The resulting mixture was stirred slightly for 4 hours at 110 ° C. It was then kneaded by a three-roll mill at 60 ° C for three passes to yield a pigment particle with a maximum size of 12.5 micrometers. 22 parts by weight of a varnish and 11 parts by weight of the solvent NUMBER 7 (manufactured by Nippon Oil Co., Ltd) were added to the resulting paste ink to prepare the ink, the final product. It was compared with the normal ink that contains the same fraction of the pigment. The ink of this comparison example had a reddish hue and the crystal fraction of alpha form was 6 percent.

[Comparison Example 2] A dry mill was charged with 70 parts by weight of crude copper phthalocyanine and 35 parts by weight of modified phenol resin with rosin having a softening point of 160 ° C and ground for one hour at 160 ° C in air. The resin was extracted from the pigment composition obtained in this way and its properties were measured. The reduction in solubility was observed. Then 32 parts by weight of the printing ink varnish and 11 parts by weight of the solvent NUMBER 7 (Nippon Oil Co., Ltd.) were added to 24 parts by weight of the milled material obtained in this manner. The resulting mixture was stirred slightly for 3 hours at 90 ° C. The mixture was then kneaded by a 3-cylinder mill at 60 ° C during a single pass to yield the pigment particle with a maximum size of 7.5 microns. 22 parts by weight of a varnish and 11 parts by weight of the solvent NUMBER 7 were added (Nippon Oil Co., Ltd.) to the resulting paste ink to prepare the ink, the final product and compared with the normal ink containing the same pigment fraction. The ink of this comparison example had lower dispersibility in water compared to normal ink.

[Comparison Example 3] A dry grinder was charged with 70 parts by weight of crude copper phthalocyanine and 70 parts by weight of modified phenol resin with rosin having a softening point of 160 ° C. They were milled for 1 hour at 80 ° C in air. The resin was extracted from the pigment composition obtained in this manner and its properties were tested. A reduction in solubility was observed. Then 16 parts by weight of the printing ink varnish and 19 parts by weight of the solvent NUMBER 7 (Nippon Oil Co., Ltd.) to 32 parts by weight of the ground material obtained in this way. The resulting mixture was stirred slightly for 2 hours at 100 ° C. The mixture was then kneaded by a three cylinder mill at 60 ° C during a single pass, to yield a dispersed pigment particle of size less than 7.5 microns. Then 22 parts by weight of a varnish and 11 parts by weight of the solvent NUMBER 7 (Nippon Oil., Ltd.) were added to the paste ink obtained in this way to prepare the ink, the final product. It was compared with normal ink containing the same pigment fraction. The ink of this comparison example had lower dispersibility in water, compared to normal ink. The crystal fraction of alpha form was less than 1 percent.

[Example 4] A dry grinder was charged with 70 parts by weight of crude copper phthalocyanine and 35 parts by weight of rosin modified phenolic resin and ground for one hour at 80 ° C in a deoxygenated atmosphere. Then 32 parts by weight of the printing ink varnish and 11 parts by weight of the solvent NUMBER 7 (Nippon Oil Co., Ltd.) were added to 24 parts by weight of the ground material obtained in this way. The resulting mixture was stirred slightly for 2 hours at 90 ° C and then kneaded by a three cylinder mill at 60 ° C during a single pass to yield a pigment particle size of less than 7.5 microns. Then 22 parts by weight of a varnish and 11 parts by weight of the solvent NUMBER 7 (Nippon Oil Co., Ltd.) were added to the resulting paste ink to prepare the ink, the final product. It was compared with the normal ink that contains the same fraction of the pigment. The ink of this example had the crystal fraction of alpha form of less than 1 percent. His hue, however, was slightly reddish.

[Example 5] A dry grinder was charged with 70 parts by weight of crude copper phthalocyanine and 7 parts by weight of rosin-modified phenolic resin and ground for one hour at 90 ° C in a deoxygenated atmosphere. Then 22 parts by weight of the resulting ground material was added to 100 parts by weight of water and 60 parts by weight of isobutanol. The resulting mixture was stirred slightly for one hour under azeotropic conditions and subsequently isobutanol was removed by distillation. Then, 8 parts by weight of 35 percent hydrochloric acid was added for acid purification. The purified mixture was then filtered and dried. The ink obtained in this way had the crystal fraction of alpha form of less than 1 percent. His hue, however, was slightly reddish.

[Example 6] A dry grinder was charged with 70 parts by weight of crude copper phthalocyanine, 30 parts by weight of the modified phenolic resin with rosin and 5 parts by weight of the solvent NUMBER 7 (Nippon Oil Co., Ltd.) and ground during a hour at 80 ° C in a deoxygenated atmosphere. Then 24 parts by weight of the resultant ground material was added to 36 parts by weight of a printing ink varnish and 7 parts by weight of the solvent NUMBER 7 (Nippon Oil Co., Ltd.) and the resulting mixture was stirred gently for 2 hours. hours at 90 ° C. The mixture was then kneaded by a three cylinder mill at 60 ° C during a single pass, to yield the dispersed pigment of a particle size of less than 7.5 microns. Then 22 parts by weight of a varnish and 11 parts by weight of the solvent NUMBER 7 (Nippon Oil Co., Ltd.) were added to the resulting paste ink to obtain the ink, the final product. It was compared with normal ink containing the same pigment fraction. The ink in the example had qualities equivalent to the normal ink in firmness in color, luster and hue. The crystal fraction of alpha form was less than 1 percent.

[Example 7] A dry grinder was charged with 70 parts by weight of crude copper phthalocyanine, 63 parts by weight of a modified phenol resin with rosin and 7 parts by weight of solvent NUMBER 7 (Nippon Oil Co., Ltd.) and ground during a hour at 70 ° C in a deoxygenated atmosphere.

Then 22 parts by weight of a printing ink varnish and 13 parts by weight of the solvent NUMBER 7 were added.

(Nippon Oil Co., Ltd.) to 32 parts by weight of the resulting milled material. The resulting mixture was stirred slightly for 2 hours at 90 ° C and then kneaded by a three cylinder mill at 60 ° C during a single pass to yield a dispersed pigment particle of size less than 7.5 microns. Then 22 parts by weight of a varnish and 11 parts by weight of the solvent NUMBER 7 (Nippon Oil Co., Ltd.) were added to a paste ink obtained in this manner to obtain the ink, the final product was compared with the normal ink that contains the same fraction of the pigment. The ink in the example had qualities equivalent to the normal ink in firmness in color, luster and hue. The crystal fraction of alpha form was less than 1 percent.

[Example 8] One hundred parts by weight of the same phenol resin modified with rosin as used in Example 7 were heated to the softening temperature. Then 10 parts by weight of the solvent NUMBER 7 (Nippon Oil Co., Ltd.) was added to this preparation so that the solvent remained in the resin. A dry mill was charged with 70 parts by weight of crude copper phthalocycin and 70 parts by weight of the modified phenol resin with rosin where the solvent was contained and ground for one hour at 70 ° C in a deoxygenated atmosphere. Then 32 parts by weight of the resulting milled material were added to 22 parts by weight of a printing ink varnish and 13 parts by weight of the solvent NUMBER 7 (Nippon Oil Co., Ltd.). The resulting mixture was stirred slightly for 2 hours at 90 ° C. The mixture was then kneaded by a three cylinder mill at 60 ° C during a single pass to yield a dispersed pigment particle of size less than 7.5 microns. Then 22 parts by weight of a varnish and 11 parts by weight of the solvent NUMBER 7 (Nippon Oil Co., Ltd.) were added to the resulting paste ink to obtain the ink, the final product. It was compared with the normal ink that contains the same fraction of the pigment. The ink in the example had qualities equivalent to the normal ink in firmness in color, luster and hue. The crystal fraction of alpha form was less than 1 percent.

[Example 9] One hundred parts by weight of the same phenol resin modified with rosin as used in Example 7 was heated to the softening temperature. Then 20 parts by weight of the solvent NUMBER 7 (Nippon Oil Co., Ltd.) was added thereto so that the solvent would be contained in the resin. A dry grinder was charged with 70 parts by weight of crude copper phthalocyanine and 7 parts by weight of the modified phenol resin with rosin, where the solvent was contained and ground for one hour at 90 ° C in a deoxygenated atmosphere. Then 22 parts by weight of the resulting ground material were added to 100 parts by weight of water and 60 parts by weight of isobutanol. The resulting mixture was stirred slightly for one hour under azeotropic condition and then the isobutanol was removed by distillation. Then 8 parts by weight of 35 percent hydrochloric acid were added to achieve acid purification. The product was then filtered and dried. The ink obtained in this way had an alpha crystal fraction of less than 1 percent. When this pigment was compared with the normal pigment, the pigment of the example had a hue equivalent to that of the normal pigment.

[Comparison Example 4] A dry grinder was charged with 70 parts by weight of crude copper phthalocyanine and ground for one hour at 80 ° C in a deoxygenated atmosphere. Then, 16 parts by weight of the resulting milled material were added to 48 parts by weight of the printing ink varnish and 3 parts by weight of the solvent NUMBER 7 (Nippon Oil Co., Ltd.). The resulting mixture was stirred slightly for 2 hours at 90 ° C. The mixture was then kneaded by a three cylinder mill at 60 ° C for three passes to yield a dispersed pigment particle of size not less than 10.0 microns. then 22 parts by weight of a varnish and 11 parts by weight of the solvent NUMBER 7 (Nippon Oil Co., Ltd.) were added to the resulting paste ink to obtain the ink, the final product. It was compared with the normal ink that contains the same fraction of the pigment. The ink of this comparison example had the crystal fraction of alpha form of less than 1 percent. His hue, however, was reddish. The present invention can be practiced in other modalities than those previously described. The terms and terms used in this specification are intended for explanation purposes only and in no way should be construed as limiting the scope of the present invention. Therefore, any variation within the scale of the appended claims and equivalents as to the essence of the invention should be considered as within the claims and scope of this invention.

Claims (20)

R E I V I N D I C A C I O N E S:

1. A method for preparing a pigment composition related to the milling of crude copper phthalocyanine comprising the steps of: adding a resin to the crude copper phthalocyanine, and carrying out the dry milling in an atmosphere that is selected from a group which consists of a deoxygenated atomsphere and an atmosphere containing inert gas.

2. The method for preparing a pigment composition according to claim 1, wherein the resin is a phenol resin modified with rosin.

3. The method for preparing a pigment composition according to claim 2, wherein the amount of the resin to be added is from 1 percent to 200 percent by weight of the crude copper phthalocyanine.

4. The method for preparing a pigment composition according to claim 2, wherein the amount of the resin to be added is from 5 percent to 100 percent by weight of crude copper phthalocyanine.

5. The method for preparing a pigment composition according to claim 1, wherein the atmosphere temperature for dry milling is between 60 ° C and 200 ° C.

6. The method for preparing a pigment composition according to claim 1, wherein the atmosphere temperature for dry milling is between 80 ° C and 170 ° C. The method for preparing a pigment composition according to claim 1, wherein the resin and a solvent in an amount ranging from 0.5 percent to 20 percent by weight of the resin, are added to the copper phthalocyanine . The method for preparing a pigment composition according to claim 1, wherein the solvent is added to the resin an amount ranging from 0.5 percent to 20 percent of the resin before the addition of the resin to the resin. phthalocyanine crude copper. 9. The method for preparing a pigment composition according to claim 7, wherein the solvent is a printing ink solvent. 10. A pigment composition, wherein a resin is added to the crude copper phthalocyanine and dry milled in an atmosphere that is selected from the group consisting of a deoxygenated atmosphere and an atmosphere containing inert gas. 11. The pigment composition according to claim 10, wherein the resin is a phenolic resin modified with rosin. 12. The pigment composition according to claim 11, wherein the amount of the resin to be added is within the range of 1 percent to 200 percent by weight of the crude copper phthalocyanine. The pigment composition according to claim 11, wherein the amount of the resin to be added is within the range of 5 percent to 100 percent by weight of the crude copper phthalocyanine. 14. The pigment composition according to claim 10, wherein the atmosphere temperature for dry milling is between 60 ° C and 200 ° C. 15. The pigment composition according to claim 10, wherein the atmosphere temperature for dry milling is between 80 ° and 170 ° C. 16. The pigment composition according to claim 10, wherein the resin and a solvent in an amount ranging from 0.5 percent to 20 percent by weight of the resin, are added to the crude copper phthalocyanine. The pigment composition according to claim 10, wherein the solvent is added to the resin in an amount ranging from 0.5 percent to 20 percent by weight of the resin, before the addition of the resin to the resin. phthalocyanine crude copper. 18. The pigment composition according to claim 16, wherein the solvent is a printing ink solvent. 19. A method for preparing a printing ink, wherein the pigment composition of claim 10 is added to a printing ink solvent to produce the printing ink. 20. A method for preparing a printing ink, wherein the pigment composition of claim 10 is added to a printing ink varnish to produce the printing ink.