Title of Invention	PIGMENT DISPERSANTS PIGMENT DISPERSIONS, AND WRITING OR RECORDING PIGMENT INKS
Abstract	A pigments dispersion for the production of writing. A dispersant for organic pigments, comprising a compound represented by the following formula (I): Wherein X and X' each independently represent a hydrogen atom, a hydroxyl group, an alkoxy group, a primary, secondary or tertiary amino group, or an acylamino group; Y represents an anthraquinonylamino, phenylamino or phenoxy group having a hydrogen atom, a hydroxyl group, an alkoxy group, a primary, secondary or tertiary amino group, or an acylamino group at the 4-position or 5- position thereof; A and B each independently represent an alkyl group, a cycloalkyl group or an aryl group, and at least one of A and B has at least one substituent group containing a basic nitrogen atom; and Z represents a hydrogen atom, a cyano group, a halogen atom, an alkyl group, an alkoxy group, a nitro group, a benzoylamino group or a 3-benzoyl group, and said 3-benzoyl group may be fused together with X to form an acridone ring.

Title of Invention

PIGMENT DISPERSANTS PIGMENT DISPERSIONS, AND WRITING OR RECORDING PIGMENT INKS

Abstract

A pigments dispersion for the production of writing. A dispersant for organic pigments, comprising a compound represented by the following formula (I): Wherein X and X' each independently represent a hydrogen atom, a hydroxyl group, an alkoxy group, a primary, secondary or tertiary amino group, or an acylamino group; Y represents an anthraquinonylamino, phenylamino or phenoxy group having a hydrogen atom, a hydroxyl group, an alkoxy group, a primary, secondary or tertiary amino group, or an acylamino group at the 4-position or 5- position thereof; A and B each independently represent an alkyl group, a cycloalkyl group or an aryl group, and at least one of A and B has at least one substituent group containing a basic nitrogen atom; and Z represents a hydrogen atom, a cyano group, a halogen atom, an alkyl group, an alkoxy group, a nitro group, a benzoylamino group or a 3-benzoyl group, and said 3-benzoyl group may be fused together with X to form an acridone ring.

Full Text	PIGMENT DISPERSANTS, PIGMENT DISPERSIONS AND WRITING OR RECORDING PIGMENT INKS BACKGROUND OF THE INVENTION a) Field of the Invention This invention relates to dispersants for organic pigments (hereinafter simply referred to as "pig- ments"), pigment dispersions and writing or recording pigment inks, and more specifically to pigment dis- persants and also to pigment dispersions making use of the pigment dispersants, having excellent fluidity, dispersion stability, storage stability and the like and suited especially for the production of writing or recording pigment inks. b) Description of the Related Art Marking inks for use in writing instruments, which make use of bundled fiber tips or felt tips, have conventionally been made of resins, pigments and sol- vents, and as the pigments, dyes have been employed. As the solvents, ester or aromatic solvents have been used from the standpoint of solubility for the resins and also solubility for the dyes. It is however desired to avoid use of aromatic solvents, because they give deleterious effects on the health of workers (organic solvent intoxication) and they themselves are air pollutants. Although there is a move toward water-based writing inks, solvent-based maker pens are still employed widely. This can be at- tributed to the excellent writing performance of solvent-based inks on plastic films such as poly- ethylene films and also to the superb drying character- istics of the solvent-based inks shortly after written on plastic films. Ink-jet printing, on the other hand, is a digital printing controlled by a computer. Printing informa- tion signals are supplied to a printer directly from the computer, so that no plate-making is needed. Ink- jet printing is therefore suited particularly for the printing of various images in small numbers of copies, and recent advancements in ink-jet printers have made it possible to perform printing of a variety of highly- detailed large images. Ink-jet printing inks are required to have low viscosity and excellent stability. There are organic- solvent-based inks making use of dyes, but as pigment- type inks, water-based inks are used because ink-jet printing inks making use of pigments involve technical difficulties. However, water-based inks contain, as vehicles, resins at extremely low concentrations so that good color developments are not available. Water- based inks are also accompanied by a problem of adhe- sion to plastic films. Under these circumstances, there is a strong desire for the development of alcohol-based ink-jet printing inks making use of pig- ments and assuring good color developments. Incidentally, as is observed from paints and the like, the conventional technology expects much on the dispersing power of a resin for a pigment upon dispers- ing the pigment on a resin solution. When the dispers- ing power of the resin is insufficient for the pigment, a pigment dispersant (pigment treatment) (hereinafter simply referred to as "a pigment dispersant) has been employed. In general paints, sufficient dispersion of pigments is feasible with conventional dispersants. Compared with paints, however, writing or record- ing pigment inks are required to have extremely low viscosity and in addition, to have an extremely high degree of dispersion of pigments. Despite these re- quirements, use of conventional resins and dispersants is unable to achieve sufficient dispersion of pigments or leads to changes in the viscosity of pigment disper- sions along the passage of time due to desorption of the dispersant from the pigments and insufficient com- patibility between the pigments and the resins, thereby making it extremely difficult to obtain pigment disper- sions which meet the property and performance require- ments . If an alcoholic solvent such as ethanol can be used as a solvent in an organic-solvent-based pigment ink, deleterious effects on the health of users of writing instruments and people studying or working in the same environment as the users can be reduced, the problem of air pollution can be lessened owing to the avoidance of an organic solvent, and further, the prob- lems of drying characteristics and wetting to plastic films, said problems being inherent to water-based inks, can also be eliminated. Moverover, alcoholic solvents are resources reproducible in the natural world so that use of such solvents is preferred. None- theless, with resins soluble in conventionally-known alcoholic solvents, it is still extremely difficult to obtain pigment inks satisfactory in the requirements for low viscosity, high dispersion and high dispersion stability even if dispersants are used. SUMMARY OF THE INVENTION An object of the present invention is therefore to provide a dispersant which is excellent in the dis- persibility of pigments and permits production of a pigment dispersion excellent in the stability of vis- cosity. Another object of the present invention is to provide a pigment dispersion, writing ink or recording ink, which is using a pigment as a coloring matter, contains a resin - which is soluble in an organic sol- vent, especially an alcoholic solvent - in a sufficient amount relative to the pigment, has a low viscosity, good pigment dispersibility and excellent viscosity stability, and gives less deleterious effects on the health of a user of a writing instrument or recording apparatus and people studying or working in the same environment as the user. To achieve the above-described objects, the pres- ent invention provides an dispersant for organic pig- ments, comprising a compound represented by the follow- ing formula (I): wherein X and X' each independently represent a hydrogen atom, a hydroxyl group, an alkoxy group, a primary, secondary or tertiary amino group, or an acylamino group; Y represents an anthraquinonylamino, phenylamino or phenoxy group having a hydrogen atom, a hydroxyl group, an alkoxy group, a primary, secondary or tertiary amino group, or an acylamino group at the 4- position or 5-position thereof; A and B each indepen- dently represent an alkyl group, a cycloalkyl group or an aryl group, and at least one of A and B has at least one substituent group containing a basic nitrogen atom; and Z represents a hydrogen atom, a cyano group, a halogen atom, an alkyl group, an alkoxy group, a nitro group, a benzoylamino group or a 3-benzoyl group, and the 3-benzoyl group may be fused together with X to form an acridone ring; a pigment dispersion comprising an organic pigment, a dispersant, a film-forming resin and an organic solvent, wherein the dispersant is the above-described dispersant; a writing or recording pig- ment ink comprising the dispersion; and a writing in- strument or recording apparatus comprising the ink (the pigment dispersion and the writing ink or recording ink will hereinafter be collectively called "the ink"). The term "at least one substituent group contain- ing a basic nitrogen atom" as used herein may mean a primary, secondary or tertiary amino group, a quaternary ammonium group or a pyridinium group, with a tertiary amino group being particularly preferred. The dispersant according to the present invention is useful as a dispersant for a variety of conventionally-Known pigments, especially as a dis- persant for various pigments used as coloring matters in inks, various paints, various printing inks, various pigment printing agents and synthetic resins. In par- ticular, use of the dispersant according to the present invention by adding it as a dispersant to red, green yellow and purple inks makes it possible to stably pro- duce low-viscosity inks and eventually to obtain ex- cellent inks. DETAILED DESCRIPITION OF THE INVENTION AND PREFERRED EMBODIMENTS The present invention will hereinafter be de- scribed in further detail based on certain preferred embodiments. Dispersants according to the present in- vention are useful as dispersants for a variety of conventionally-known pigments used as coloring matters in various paints, various printing inks, various pig- ment printing agents and synthetic resins. An espe- cially useful application is an application as dis- persants for pigments in inks. Accordingly, the pres- ent invention will hereinafter be described by taking inks as representative examples. The dispersants according to the present inven- tion can be prepared by the preparation process dis- closed, for example, in JP 46-33232 B, JP 46-332 33 B. or JP 46-34518 B. or a process similar to the preparation process. As an example, a dispersant can be obtained by reacting 1 mole of l-amino-5-benzoylaminoanthra- quinone, 1 mole of aniline or phenol and 1 mole of cyanuric chloride at 130 to 160°C for 2 to 6 hours in an inert solvent such as o-dichlorobenzene, adding 1 mole of a polyamine containing at least one secondary amino group and at least one tertiary amino group and containing no primary amino group, and then reacting them at 150 to 170°C for 3 to 4 hours. Illustrative of the "polyamine containing at least one secondary amino group and at least one tertiary amino group and containing no primary amino group" employed in the above-described process are: N, N, N'-trimethy1-ethylenediamine, N,N-dimethyl-N'-ethyl-ethylenediamine, N, N-diethyl-N'-methyl-ethylenediamine, N,N-dimethyl-N'-ethyl-propylenediamine, N,N,N'-trimethy1-propylenediamine, N,N,N'-triethyl-propylenediamine, N, N, N ' -trimethy1-hexamethylenediamine, N, N-diethyl-N"-methyl-p-phenylenediamine, Among the dispersants according to the present invention available by the above-described processes, preferred dispersants are compounds represented by the following formula (1), more preferred dispersants are compounds represented by the formula (2) , and particu- larly preferred dispersants are compounds represented by the following formula (3): wherein X, X', Y and Z have the same meanings as defined above; Rx to R4 may be the same or different and each independently represent a substituted or un- substituted alkyl or cycloalkyl group, and R1 and R2 and/or R3 and R4 may be fused together with the ad- jacent nitrogen atom thereof to form a heterocyclic ring which may additionally contain a further nitrogen atom, an oxygen atom or a sulfur atom; and R5 and R6 each independently represent an alkylene group, a cycloalkylene group or an arylene group. wherein X, X', Y, Z and R1 to R4 have the same meanings as defined above; and n and m each independently stand for an integer of from 2 to 30. Incidentally, the aminoacyl groups in the above- described formula (I) and the above-described formulas (1) to (2), are groups represented by -NHCOR, in which R is a phenyl group, a methyl group, an ethyl group, a propyl group, a butyl group, or the like. wherein X and X' each independently represent a hydrogen atom or a benzoylamino group; Z represents a hydrogen atom; R1 to R4 may be the same or different and each independently represent a methyl group or an ethyl group; and n and m each independently stand for 2 or 3. Specific examples of preferred dispersants in the present invention can include, but are not limited to, the followings in which X represents a benzoylamino and the quaternary ammonium compounds of Specific Exam- ples 1-6, 9-14 and 17-19 and the pyridinium compounds of Specific Examples 7-8 and 15-16. Inks according to the present invention are formed of the above-described dispersants, pigments, film-forming resins and organic solvents. Conventionally-known pigments are all usable as pig- ments in the present invention. For example, pigments such as azo pigments, condensed azo pigments, anthra- quinone pigments, perylene/perinone pigments, indigo- thioindigo pigments, isoindolinone pigments, azomethine pigments, azomethineazo pigments, quinacridone pig- ments, phthalocyanine blue, dioxazine violet, aniline black and carbon black can be used. Particularly preferred pigments can include C.I. pigment red (hereinafter abbreviated as "P-R.") 177, P.R. 254, P.R. 242, C.I. pigment green (hereinafter abbreviated as "P.G.") 36, C.I. pigment blue (hereinafter abbreviated as "P.B.") 15:2, P.B. 15:6, P.B. 60, C.I. pigment yel- low (hereinafter abbreviated as "P.Y.") 138, P.Y. 185, P.Y. 150, P.Y. 139, C.I. pigment violet 23, C.I. pig- ment black (hereinafter abbreviated as "P.BL." 6, P.BL. 7. Conventionally-known organic solvents employed in various paints, coating formulations, printing inks and the like are all usable as organic solvents in the present invention. When using inks according to the present invention as inks for writing instruments or recording apparatuses, use of alcoholic solvents is preferred. As alcoholic solvents, solvents containing alcohols the boiling points of which are 150°C or lower are preferred. Alcohols amount to at least 10 wt.%, preferably to 50 to 100 wt.% of alcoholic solvents. Preferred examples of alcohols can include ethanol, propanol, methoxypropanol, ethoxypropanol, and propyloxyethanol. They can be used either singly or in combination. Solvents other than these alcohols can also be used to extents not contrary to the spirit of the present invention. For example, ethyl acetate, propyl acetate, cyclohexane, methylcyclohexane, ethyl- cyclohexane, methyl ethyl ketone, methyl propyl ketone and the like can be used in combination. The film-forming resin (hereinafter simply referred to as a "resin") employed in the present in- vention is required to be soluble in the above- described organic solvent, especially the alcoholic solvent descried above. Such a resin comprises, as constituent monomers, an addition-polymerizing monomer containing a carboxyl group, a hydroxy1 group or an amido group and a monomer addition-polymerizable with the addition-polymerizing monomer. A description will hereinafter be made about the monomers which make up the resin for use in the present invention. Examples of the carboxyl-containing monomer can include acrylic acid and methacrylic acid; fumaric acid, maleic acid, itaconic acid, alkyl monoesters thereof, and hydroxyalkyl monoesters thereof; and monoesters between hydroxyalkyl (meth)acrylates, such as hydroxyethyl (raeth)acrylate and hydroxypropyl (meth)acrylate, and dibasic acids, for example, suc- cinic anhydride, phthalic anhydride and cyclohexane- dicarboxylic acid anhydride. Incidentally, acrylic acid and methacrylic acid will be called (meth) acrylic acid in the present invention. Examples of the hydroxy1-containing monomer can include hydroxyalkyl (meth)acrylates, for example, hydroxyethyl (meth)acrylate and hydropropyl (meth)acrylate; esters of monoesters between the above- described hydroxyalkyl (meth)acrylates and dibasic aqids with dihydroxyalkyl compounds, for example, monoesters of monoesters between hydroxyethyl (meth) acrylate and hydroxypropyl (meth) acrylate and succinic acid, phthalic acid and cyclohexanecarboxylic acid with dihydroxyalkyl compounds such as ethylene glycol and propylene glycol. The carbon numbers of the alkyl groups in the above-described carboxyl- and hydroxyl-containing monomers range from about 1 to 12. Examples of the amido-containing monomer can in- clude (meth)acrylamides and N-substituted (meth)acryl- amides, for example, (meth)acrylic butoxymethylamide, N-tert-butylacrylamide, N-tert-butylmethacrylamide, diacetoneacrylamide, N-isopropylacrylamide, N,N- dimethylacrylamide, N,N-diethylacrylaraide, N-methylol- (meth)acrylamide, and N-alkyloxyethyl (meth)acrylamide. In addition to the above-described monomers, addition-polymerizing monomers copolymerizable with the above-described respective monomers can be used to ex- tents soluble in the alcoholic solvent in order to im- part waterproofness, flexibility and/or other physical properties to the resin. Examples of such monomers can include (meth)acrylate esters, for example, methyl (meth)aerylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, octyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, cyclohexyl (meth)acrylate, benzyl (meth)acrylate, isobornyl (meth)acrylate, and tetraful- furyl (meth)acrylate; styrene and styrene derivatives, for example, a-methylstyrene; dialkyl esters of dibasic acids, for example, dialkyl maleates, dialkyl fumarates, and dialkyl itaconates; and vinyl acetate, and (roeth)acrylonitrile. The resin for use in the present invention can be obtained by using the above-described monomers and copolymerizing them, for example, by suspension polymerization or solution polymerization, which uses an alcoholic solvent, in the presence or absence of a conventionally-known radical polymerization initiator. As a resin for use in the present invention, it is preferred to use a resin in which a monomer between an alkyl (meth) acrylate and a dibasic acid - said monomer being represented by the following formula: CH2=C(R1)- COO-R2-0-CO-R3-COOH in which R1 represents a hydrogen atom or a methyl group, R2 represents an alkylene chain which contains 2 to 6 carbon atoms and may contain a branched chain, R3 represents an alkylene group which may contain a branched chain or unsaturated group - is copolymerized at least a part of a copolymer. A blend of the copolymer with a copolymer free of the above- described specific monomers may also be used. Whichever resin is used, it is preferred to contain units of a monoester monomer between hydroxyalkyl (meth) acrylate and a dibasic acid in a proportion of from 1 to 50 wt.%, preferably from 3 to 4 0 wt.% based on the whole resin. If the content of the monomer units is too low, the resin is not very effective for dispersing pigments. If the content of the monomer units is too high, on the other hand, writing matter or printed matter has lowered alkali resistance. It is therefore not preferred to contain the monomer units outside the above range. To obtain the resin by copolymerizing a mixture of the above-described monomers, the monoester of the hydroxyalkyl (meth)acrylate and the dibasic acid may account preferably for 1 to 50 wt.%, more preferably for 3 to 40 wt.% of the monomer mixture. The propor- tion (s) of other monomer(s) can be suitably determined such that the resulting resin is soluble in the al- coholic solvent and can satisfy its performance re- quirements, and no particular limitation is imposed on their proportions. The number average molecular weight of the resin (the number average molecular weight as obtained by measuring the resin by GPC and converting the data with reference to the corresponding data of standard polystyrene) ranges generally from 2,000 to 100,000, preferably from 2,000 to 50,000. The acid value of the resin ranges generally from 0.5 to 300 mgKOH/g, preferably from 5 to 180 mgKOH/mg. The ink according to the present invention can be produced in a similar manner as in the production of conventional inks and paints by using the above- described pigment, dispersant, film-forming resin and organic solvent, and no particular limitation is im- posed on the production method itself. Illustrative productions methods can include a method in which the pigment, subsequent to its advance treatment with the dispersant, is dispersed in a solution of the resin in an alcoholic solvent; and a method in which the un- treated pigment and the dispersant are mixed with the resin solution and the pigment is subjected to disper- sion processing in a disperser. When the method that the pigment, subsequent to its advance treatment with the dispersant, is dispersed in the solution of the resin in the alcoholic solvent is adopted, the treatment of the pigment can be prac- ticed, for example, as will be described next. (1) Subsequent to dissolution of the pigment and the dis- persant in sulfuric acid or the like, the resultant solution is poured into water. The thus-obtained mix- ture is alkalinized to have both of the pigment and dispersant precipitated as a solid solution. The solid solution is collected by filtration, washed with water, dried and then ground, whereby the pigment is obtained in a treated form. (2) The dispersant is converted into a salt with sulfuric acid, hydrochloric acid, acetic acid or the like. The salt is mixed with the pigment in water and, if necessary, the resultant mix- ture is subjected to dispersion processing in a dis- perser to have the dispersant adsorbed on pigment sur- faces. The thus-treated pigment is caused to precipitate under alkaline condition, collected by fil- tration, washed with water, dried and then ground, whereby the pigment is obtained in the treated form. (3) The dispersant is dissolved in a liquid organic acid such as acetic acid, followed by the addition of the pigment. After the dispersant is allowed to be ad- sorbed on pigment surfaces with optional dispersing processing in a disperser, the thus-treated pigment is collected by filtration, washed with an alkaline solu- tion, washed with water, dried and then ground, whereby the pigment is obtained in the treated form. The treated pigment obtained as described above is dis- persed in the solution of the resin in an alcoholic solvent to produce the ink of the present invention. When the method that the untreated pigment and the dispersant are mixed with the resin solution and the pigment is subjected to dispersion processing in a disperser is adopted, the pigment and the dispersant are added to the solution of the resin in the alcoholic solvent and subsequent to optional provisional agita- tion, the mixture is dispersed in a disperser to obtain an ink. No particular limitation is imposed on the disperser which can be used in the present invention. Examples can include a kneader, an attritor, a ball mill, a sand mill and a horizontal disperser with tum- bling means contained therein, said sand mill and horizontal disperser making use of glass, zircon or the like, and a colloid mill. Upon using the dispersant- treated pigment, it is also possible to further dis- perse the dispersant-treated pigment in a solid resin to obtain pigment chips and then to dissolve the pig- ment chips in an alcoholic solvent to obtain an ink. Subsequent to the dissolution of the pigment chips, a resin may be added as needed. Pigment chips can be obtained, for example, by one of the following methods: (1) A solid resin ob- tained by suspension polymerization or a solid resin collected from a resin solution obtained by solution polymerization and a dispersant-treated pigment are kneaded under heat by using a kneader, a Banbury mixer, a mixing roll, a three-roll mill or the like either singly or in combination such that the pigment is dis- persed in the resin. The resultant pigment-dispersed resin is then ground or chopped to obtain chips. (2) A solution of a resin in a water-soluble solvent and a presscake of a dispersant-treated pigment are mixed in a kneader, followed by heating to the softening point of the resin or higher to remove water. If necessary, the pigment is dispersed by using a three-roll mill, an extruder or the like. The resultant pigment-dispersed resin is ground or chopped to obtain pigment chips. (3) A presscake of a dispersant-treated pigment and a solid resin are subjected to flushing at the softening temperature of the resin or higher. In the ink according to the present invention, the above-described dispersant may be used generally in a proportion of from 0.5 to 50 parts by weight, preferably in a proportion of from 1 to 30 parts by weight per 100 parts by weight of the pigment. On the other hand, the pigment may be used generally in a pro- portion of from 5 to 500 parts by weight per 100 parts by weight of the resin. The concentration of the pigment in the ink ac- cording to the present invention may be from 0.3 to 50 wt.% in general, with 0.5 to 30 wt.% being preferred, although it varies depending on the pigment. The vis- cosity of the ink may range generally from 1 to 50 mPa.s, preferably from 2 to 30 mPa.s. Depending on the construction of the writing instrument, a viscosity lower than 7 mPa.s may be required in some instances. It is particularly important for an ink to be equipped with excellent stability in viscosity along the passage of time. Owing to the use of the above-described dis- persant and resin along with a pigment, the ink accord- ing to the present invention has been imparted with ex- cellent time-dependent stability in viscosity. A variety of additives can also be added to the ink of the present invention. Illustrative of such ad- ditives are fastness improvers such as ultraviolet ab- sorbers and antioxidants; anti-settling agents; release agents and releasability improvers; perfumes and antimicrobial agents; plasticizers; and drying in- hibitors. If necessary, one or more dyes can be added further. As a resin, a resin which has compatibility with the resin for use in the present invention may also be used in combination to an extent not lowering the dispersion stability of the pigment. In general, the thus-obtained ink can be used as is. It is however preferable to process the ink fur- ther in a centrifugal separator or an ultracentrifugal separator or through a filter, because removal of coarse particles of the pigment, which may exist in a trace amount in some instances, makes it possible to heighten the reliability of the writing instrument or recording apparatus. The writing instrument according to the present invention can be obtained by filling the ink of this invention, which has been obtained as described above, in a casing equipped with a porous tip. No particular limitation is imposed on the casing insofar as it has a size and shape convenient for writing as in the case of a variety of conventional writing instruments fitted with porous tips. The material of the casing, includ- ing its cap, can be a metal, a plastic or a composite, material thereof insofar as it is practically free from solvent permeation. No limitation is imposed on the structure or material of the porous tip insofar as it allows the ink to move from the interior of the casing to the free end of the tip as writing proceeds. However, excellent writing characteristics, durability and solvent resistance are required. Usable examples of fibers of bundled fiber tips and felt tips can include synthetic fibers such as polyester, polypropylene, nylon, polyacrylonitrile and vinylon fibers; cellulose and cellulose-derived regenerated fibers; and natural fibers such as wool, silk and cotton. Usable examples of open-cell foamed plastic products can include rigid or flexible urethane resin foams, foams of acetalized polyvinyl alcohol, and foamed of regenerated fibers. Usable examples of ink-occluding members can include bundles fibers, felted fibers, knitted fibers, and open-cell foamed plastic products. In the above description, inks making use of the dispersants according to the present invention have been referred to as representative examples. The pres- ent invention is however not limited only to inks. For example, the dispersants according to the present in- vention are useful as dispersants for a variety of conventionally-known pigments, and are useful as dis- persants for various pigments employed as coloring mat- ters in diverse paints, printing inks, pigment printing agents, synthetic resins and the like. The present invention will next be described more specifically by Examples and Comparative Examples, in which the designations of "part" or "parts" and "%" are all by weight. Example 1 Added to 600 parts of o-dichlorobenzene were 62 parts of 1-aminoanthraquinone and 25 parts of cyanuric chloride, followed by stirring at 130°C for 5 hours. After cooling, 50 parts of N,N,N",N"-tetraethyl- diethylenetriamine were added further, and the resultant mixture was stirred at 170°C for 3 hours. Subsequent to filtration, the thus-obtained filtercake was washed with ethanol and then dried, whereby the above-described specific example (1) was obtained as Dispersant 1. Example 2 In a similar manner as in Example 1, the above- described specific example (2) was obtained as Dis- persant 2 by successively subjecting l-aminoanthra- quinone and 3,3•-iminobis(N,N-diroethylpropylamine) to condensation reactions with cyanuric chloride. Example 3 In a similar manner as in Example 1, the above- described specific example (3) was obtained as Dis- persant 3 by successively subjecting 1-aminoanthra- quinone and 3-ethyl-10-methyl-3,6,10-triazaundecane to condensation reactions with cyanuric chloride. Example 4 In a similar manner as in Example 1, the above- described specific example (4) was obtained as Dis- persant 4 by successively subjecting l-amino-5- benzoylaminoanthraquinone and 3,3'-iminobis(N,N- dimethylpropylamine) to condensation reactions with cyanuric chloride. Example 5 In a similar manner as in Example 1, the above- described specific example (5) was obtained as Dis- persant 5 by successively subjecting l-amino-5- benzoylaminoanthraquinone, aniline and 3,3'-imirio- bis(N,N-dimethylpropylamine) to condensation reactions with cyanuric chloride. Example 6 In a similar manner as in Example 1, the above- described specific example (6) was obtained as Dis- persant 6 by successively subjecting 1-arainoanthra- quinone and 5,13-di(n-butyl)-5,9,13-triazaheptadecane to condensation reactions with cyanuric chloride. Example 7 In a similar manner as in Example 1, the above- described specific example (7) was obtained as Dis- persant 7 by successively subjecting 1-aminoanthra- quinone and 2,2'-dipicolylamine to condensation reac- tions with cyanuric chloride. Example 8 In a similar manner as in Example 1, the above- described specific example (8) was obtained as Dis- persant 8 by successively subjecting 1-aminoanthra- guinone and 3,3'-dipicolylamine to condensation reac- tions with cyanuric chloride. Example 9 In a similar manner as in Example 1, the above- described specific example (9) was obtained as Dis- persant 9 by successively subjecting l-amino-4- benzoylaminoanthraquinone and N,N,l,N,,-tetraethyl- diethylenetriamine to condensation reactions with cyanuric chloride. Example 10 In a similar manner as in Example 1, the above- described specific example (10) was obtained as Dis- persant 10 by successively subjecting l-amino-4- benzoylaminoanthraquinone and 3,3'-iminobis(N,N- dimethylpropylamine) to condensation reactions with cyanuric chloride. Example 11 In a similar manner as in Example 1, the above- described specific example (11) was obtained as Dis- persant 11 by successively subjecting l-amino-4- benzoylaminoanthraquinone and 3-ethyl-10-methyl-3,6,10- triazaundecane to condensation reactions with cyanuric chloride. Example 12 In a similar manner as in Example 1, the above- described specific example (12) was obtained as Dis- persant 12 by successively subjecting l-amino-4,5- dibenzoylaminoanthraquinone and 3,3•-iminobis(N,N- dimethylpropylamine) to condensation reactions with cyanuric chloride. Example 13 In a similar manner as in Example 1, the above- described specific example (13) was obtained as Dis- persant 13 by successively subjecting l-amino-4- benzoylaminoanthraquinone, aniline and 3,3'-imino- bis(N,N-dimethylpropylamine) to condensation reactions with cyanuric chloride. Example 14 In a similar manner as in Example 1, the above- described specific example (14) was obtained as Dis- persant 14 by successively subjecting l-araino-4- benzoylaminoanthraquinone and 5,13-di(n-butyl)-5,9,13- triazaheptadecane to condensation reactions with cyanuric chloride. Example 15 In a similar manner as in Example 1, the above- described specific example (15) was obtained as Dis- persant 15 by successively subjecting l-araino-4- benzoylaminoanthraquinone and 2,2' -dipicolylamine to condensation reactions with cyanuric chloride. Example 16 In a similar manner as in Example 1, the above- described specific example (16) was obtained as Dis- persant 16 by successively subjecting l-amino-4- benzoylaminoanthraquinone and 3,3' -dipicolylamine to condensation reactions with cyanuric chloride. Example 16-2 In a similar manner as in Example 1, the above- described specific example (17) was obtained as Dis- persant 17 by successively subjecting l-amino-4- hydroxyanthraquinone and 3 , 3 '-iminobis(N,N-dimethyl- propylamine) to condensation reactions with cyanuric chloride. Example 16—3 In a similar manner as in Example 1, the above- described specific example (18) was obtained as Dis- persant 18 by successively subjecting l-amino-4- methoxyanthraquinone and 3,3'-iminobis(N,N-dimethyl- propylamine) to condensation reactions with cyanuric chloride. Example 16-4 In a similar manner as in Example 1, the above- described specific example (19) was obtained as Dis- persant 19 by successively subjecting 1-amino-acridone- 1,2(2',4'-dichloro)acridone and 3,3'-iminobis(N,N- dimethylpropylamine) to condensation reactions with cyanuric chloride. Synthesis Example of Film-Forming Resin Charged in a polymerizer were 75 parts of hydroxyethyl methacrylate, 2 5 parts of a-methylstyrene, 100 parts of methyl methacrylate, 75 parts of acryloyloxyethyl phthalate, 7 5 parts of lauryl methacrylate, 150 parts of diacetoneacrylamide, 15 parts of azobisisobutyronitrile, 550 parts of ethanol, 150 parts of methylcyclohexane and 50 parts of ethyl acetate. A cooling coil was set, followed by polymerization at 75°C for 10 hours. After cooling, the resin solution was taken out of the polyraerizer. It was provided as a resin solution. The resin content was 40%, and the viscosity was 250 mPa.s. The number average molecular weight of the resin was 8,600 as measured by GPC and converted with reference to the corresponding data of standard polystyrene, and the acid value of the resin was 39. Example 17 Dispersed in a horizontal disperser with tumbling medium contained therein were 250 parts of the above- described resin solution, 50 parts of benzidine yellow (P.Y. 83), 4 parts of Dispersant (1) of Example 1, 536 parts of ethanol, 60 parts of methylcyclohexane and 100 parts of ethoxypropanol. Coarse particles were then removed by ultracentrifugal separation, whereby an ink according to the present invention was obtained. The average particle size of the pigment was 95 nm, and the viscosity was 3.5 mPa.s. The ink was stored at 50°C for a week, but settling of the pigment was not ob- served. When its viscosity was measured, it was still 3.5 mPa.s, thereby indicating no change in viscosity. The ink was next filled in a pen casing equipped with a bundled fiber tip, and a writing test was con- ducted on a polyethylene film. Smooth writing was fea- sible. Further, 20 parts of ethoxypropanol and 5 parts of benzyl alcohol were added further to 100 parts of the ink. Using the thus-obtained ink, printing was performed by an ink-jet printer. Good printed matter was obtained. Examples 18-24 Yellow inks were obtained in a similar manner as in Example 17 except that the dispersants of Examples 2-8 were used as dispersants, respectively. Those yel- low inks were then ranked as in Example 17. The results are presented in Table 1 together with the results of Example 17. In the table, "A" indicates good in both writing characteristics and ink-jet printability, while "B" indicates insufficient writing characteristics or insufficient ink-jet printability. Comparative Example 1 A yellow ink was obtained in a similar manner as in Example 17 except that the dispersant was not used. The ink was ranked as in Example 17. The results are also presented in Table 1. Example 25 Ten (10) parts of Dispersant 2 were dissolved in 100 parts of an aqueous solution which contained 5 parts of glacial acetic acid. The resultant solution was added to a slurry of a red pigment (P.R. 254; pig- ment content: 100 parts), followed by stirring for 60 minutes. A 10% aqueous solution of sodium hydroxide was then gradually added to adjust the pH of the system to 8.5. After the mixture was stirred for further 30 minutes, the resulting solid matter was collected by filtration, washed, dried at 90°C and then ground, whereby 108 parts of red pigment powder surface-treated with the dispersant were obtained. The thus-obtained surface-treated pigment was dispersed to a pigment content of 15% in a commercial melamine/alkyd paint by a ball mill. The colored paint so obtained had low viscosity, and showed fluidity sub- stantially close to a Newtonian flow. Further, the red paint was mixed with a commercial white melamine/alkyd paint to formulate a pale red paint. Even after stored for a week, the pale red paint was still in a homo- geneous form without any color separation. Comparative Example 2 A paint was formulated in a similar manner as in Example 25 except that the red pigment (P.R. 2 54) was used without surface treatment with Dispersant 2. The paint was ranked as in Example 25. The paint had high viscosity, and in the form of a mixed paint with a white paint, the red pigment underwent separation and settling through coagulation. Example 26 Eight (8) parts of Dispersant 3 were dissolved in 100 parts of an aqueous solution which contained 5 parts of glacial acetic acid. The resultant solution was added to a slurry of a red pigment (P.R. 254; pig- ment content: 100 parts), followed by stirring for 60 minutes. A 10% aqueous solution of sodium hydroxide was then gradually added to adjust the pH of the system to 8.5. After the mixture was stirred for further 30 minutes, the resulting solid matter was collected by filtration, washed, dried at 90°C and then ground, whereby 105 parts of red pigment powder surface-treated with the dispersant were obtained. The thus-obtained pigment composition was dis- persed in a commercial acrylic lacquer by a beads mill, whereby a red paint having a pigment content of 13% was formulated. The paint was adjusted in viscosity with a lacquer thinner and was spray-painted on an iron plate. A plate coated in a red color and having a dry film thickness of 32 µm was obtained. It was excellent in vividness, and showed a high degree of gloss. Comparative Example 3 A paint was formulated in a similar manner as in Example 26 except that the red pigment (P.R. 254) was used without surface treatment with Dispersant 3. The viscosity was adjusted likewise, and the paint was ranked as in Example 26. The surface of a coating on a plate coated in a red color was not smooth, and its gloss was low. Example 27 Dispersed in a horizontal disperser with tumbling medium contained therein were 250 parts of the resin solution prepared in the Synthesis Example of the film- forming resin, 50 parts of cyanine blue (P.B. 15-2), 4 parts of Dispersant (9) of Example 9, 536 parts of ethanol, 60 parts of methylcyclohexane and 100 parts of ethoxypropanol. Coarse particles were then removed by ultracentrifugal separation, whereby an ink according to the present invention was obtained. The average particle size of the pigment was 95 nm, and the vis- cosity was 3.8 mPa.s. The ink was stored at 50°C for a week, but settling of the pigment was not observed. When its viscosity was measured, it was still 3.8 mPa.s and accordingly, no change took place in vis- cosity . The ink was next filled in a pen casing equipped with a bundled fiber tip, and a writing test was con- ducted on a polyethylene film. Smooth writing was fea- sible. Further, 20 parts of ethoxypropanol and 5 parts of benzyl alcohol were added further to 100 parts of the ink. Using the thus-obtained ink, printing was performed by an ink-jet printer. Good printed matter was obtained. Examples 28-34 Blue inks were obtained in a similar manner as in Example 2 7 except that the dispersants of Examples 10- 16 were used as dispersants, respectively. Those blue inks were then ranked as in Example 27. The results are presented in Table 2 together with the results of Example 27. In the table, "A" indicates good in both writing characteristics and ink-jet printability, while "B" indicates insufficient writing characteristics or insufficient ink-jet printability. Comparative Example 4 A blue ink was obtained in a similar manner as in Example 28 except that the dispersant was not used. The ink was ranked as in Example 28. The results are also presented in Table 2. Example 35 Ten (10) parts of Dispersant 10 were dissolved in 100 parts of an aqueous solution which contained 5 parts of glacial acetic acid. The resultant solution was added to a slurry of a red pigment (P.R. 254; pig- ment content: 100 parts), followed by stirring for 60 minutes. A 10% aqueous solution of sodium hydroxide was then gradually added to adjust the pH of the system to 8.5. After the mixture was stirred for further 30 minutes, the resulting solid matter was collected by filtration, washed, dried at 90*C and then ground, whereby 108 parts of red pigment powder surface-treated with the dispersant were obtained. The thus-obtained surface-treated pigment was dispersed to a pigment content of 15% in a commercial melamine/alkyd paint by a ball mill. The colored paint so obtained had low viscosity, and showed fluidity sub- stantially close to a Newtonian flow. Further, the red paint was mixed with a commercial white melamine/alkyd paint to formulate a pale red paint. Even after stored for a week, the pale red paint was still in a homo- geneous form without any color separation. Comparative Example 5 A paint was formulated in a similar manner as in Example 35 except that the red pigment (P.R. 254) was used without surface treatment with Dispersant 10. The paint was ranked as in Example 35. The paint had high viscosity, and in the form of a mixed paint with a white paint, the red pigment underwent separation and settling through coagulation. Example 36 Eight (8) parts of Dispersant 11 were dissolved in 100 parts of an aqueous solution which contained 5 parts of glacial acetic acid. The resultant solution was added to a slurry of a red pigment (P.R. 254; pig- ment content: 100 parts), followed by stirring for 60 minutes. A 10% aqueous solution of sodium hydroxide was then gradually added to adjust the pH of the system to 8.5. After the mixture was stirred for further 30 minutes, the resulting solid matter was collected by filtration, washed, dried at 90°C and then ground, whereby 105 parts of red pigment powder surface-treated with the dispersant were obtained. The thus-obtained surface-treated pigment was dispersed in a commercial acrylic lacquer by a beads mill, whereby a red paint having a pigment content of 13% was formulated. The paint was adjusted in vis- cosity with a lacquer thinner and was spray-painted on an iron plate. A plate coated in a red color and hav- ing a dry film thickness of 32 µm was obtained. It was excellent in vividness, and showed a high degree of gloss. Comparative Example 6 A paint was formulated in a similar manner as in Example 36 except that the red pigment (P.R. 254) was used without surface treatment with Dispersant 11. The viscosity was adjusted likewise, and the paint was ranked as in Example 36. The surface of a coating on a plate coated in a red color was not smooth, and its gloss was low. Example 37 Dispersed in a horizontal disperser with tumbling medium contained therein were 2 50 parts of the resin solution prepared in the Synthesis Example of the film- forming resin, 750 parts of c.I. pigment black, 4 parts of Dispersant (1) of Example 1, 536 parts of ethanol, 60 parts of methylcyclohexane and 100 parts of ethoxy- propanol. Coarse particles were then removed by ultracentrifugal separation, whereby a black ink ac- cording to the present invention was obtained. The average particle size of the CB pigment was 95 nra, and the viscosity was 3.5 mPa.s. The black ink was stored at 50°C for a week, but settling of the CB pigment was not observed. When its viscosity was measured, it was still 3.5 mPa.s and accordingly, no change took place in viscosity. The black ink was next filled in a pen casing equipped with a bundled fiber tip, and a writing test was conducted on a polyethylene film. Smooth writing was feasible. Further, 20 parts of ethoxypropanol and 5 parts of benzyl alcohol were added further to 100 parts of the black ink. Using the thus-obtained black ink, printing was performed by an ink-jet printer. Good printed matter was obtained. Examples 38-44 Black inks were obtained in a similar manner as in Example 3 7 except that the dispersants of Examples 2-8 were used as dispersants, respectively. Those black inks were then ranked as in Example 37. The results are presented in Table 3 together with the results of Example 37. In the table, "A" indicates good in both writing characteristics and ink-jet printability, while "B" indicates insufficient writing characteristics or insufficient ink-jet printability. Comparative Example 7 A black ink was obtained in a similar manner as in Example 37 except that the dispersant was not used. The ink was ranked as in Example 37. The results are also presented in Table 3. Example 45 Ten (10) parts of Dispersant 2 were dissolved in 200 parts of an aqueous solution which contained 5 parts of glacial acetic acid. The resultant solution was added to a slurry of C.I. pigment black 7 (CB pig- ment content: 100 parts), followed by stirring for 60 minutes. A 10% aqueous solution of sodium hydroxide was then gradually added to adjust the pH of the system to 8.5. After the mixture was stirred for further 30 minutes, the resulting solid matter was collected by filtration, washed, dried at 90°C and then ground, whereby 108 parts of black pigment powder surface- treated with the dispersant were obtained. The thus-obtained surface-treated CB pigment was dispersed to a CB pigment content of 15% in a commer- cial melamine/alkyd paint by a ball mill. The colored paint so obtained had low viscosity, and showed fluidity substantially close to a Newtonian flow. Fur- ther, the black paint was mixed with a commercial white melamine/alkyd paint to formulate a gray paint. Even after stored for a week, the gray paint was still in a homogeneous form without any color separation. Comparative Example 8 A paint was formulated in a similar manner as in Example 45 except that the same CB pigment was used without surface treatment with Dispersant 2. The paint was ranked as in Example 45. The paint had high vis- cosity, and in the form of a mixed paint with a white paint, the CB pigment underwent separation and settling through coagulation. Example 46 Eight (8) parts of Dispersant 3 were dissolved in 100 parts of an aqueous solution which contained 5 parts of glacial acetic acid. The resultant solution was added to a slurry of C.I. pigment black 7 (CB pig- ment content: 100 parts), followed by stirring for 60 minutes. A 10% aqueous solution of sodium hydroxide was then gradually added to adjust the pH of the system to 8.5. After the mixture was stirred for further 30 minutes, the resulting solid matter was collected by filtration, washed, dried at 90°C and then ground, whereby 105 parts of black pigment powder surface- treated with the dispersant were obtained. The thus-obtained surface-treated CB pigment was dispersed in a commercial acrylic lacquer by a beads mill, whereby a black paint having a CB pigment content of 13% was formulated. The paint was adjusted in vis- cosity with a lacquer thinner and was spray-painted on an iron plate. A plate coated in a black color and having a dry film thickness of 32 µm was obtained. It was excellent in vividness, and showed a high degree of gloss. Comparative Example 9 A paint was formulated in a similar manner as in Example 46 except that the same CB pigment was used without surface treatment with Dispersant 3. The vis- cosity was adjusted likewise, and the paint was ranked as in Example 46. The surface of a coating on a plate coated in a black color was not smooth, and its gloss was low. Example 4 7 Dispersed in a horizontal disperser with tumbling medium contained therein were 250 parts of the resin solution prepared in the Synthesis Example of the film- forming resin, 750 parts of C.I. pigment black, 4 parts of Dispersant (9) of Example 9, 536 parts of ethanol, 60 parts of methylcyclohexane and 100 parts of ethoxy- propanol. Coarse particles were then removed by ultracentrifugal separation, whereby a black ink ac- cording to the present invention was obtained. The average particle size of the CB pigment was 95 nm, and the viscosity was 3.5 mPa.s. The black ink was stored at 50°C for a week, but settling of the CB pigment was not observed. When its viscosity was measured, it was still 3.5 mPa.s and accordingly, no change took place in viscosity. The black ink was next filled in a pen casing equipped with a bundled fiber tip, and a writing test was conducted on a polyethylene film. Smooth writing was feasible. Further, 20 parts of ethoxypropanol and 5 parts of benzyl alcohol were added further to 100 parts of the black ink. Using the thus-obtained black ink, printing was performed by an ink-jet printer. Good printed matter was obtained. Examples 48-54 Black inks were obtained in a similar manner as in Example 4 7 except that the dispersants of Examples 10-16 were used as dispersants, respectively. Those black inks were then ranked as in Example 47. The results are presented in Table 4 together with the results of Example 47. In the table, "A" indicates good in both writing characteristics and ink-jet printability, while "B" indicates insufficient writing characteristics or insufficient ink-jet printability. Example 55 Ten (10) parts of Dispersant 10 were dissolved in 200 parts of an aqueous solution which contained 5 parts of glacial acetic acid. The resultant solution was added to a slurry of C.I. pigment black 7 (CB pig- ment content: 100 parts), followed by stirring for 60 minutes. A 10% aqueous solution of sodium hydroxide was then gradually added to adjust the pH of the system to 8.5. After the mixture was stirred for further 3 0 minutes, the resulting solid matter was collected by filtration, washed, dried at 90°C and then ground, whereby 108 parts of black pigment powder surface- treated with the dispersant were obtained. The thus-obtained surface-treated CB pigment was « dispersed to a CB pigment content of 15% in a commer- cial melamine/alkyd paint by a ball mill. The colored paint so obtained had low viscosity, and showed fluidity substantially close to a Newtonian flow. Fur- ther, the black paint was mixed with a commercial white melamine/alkyd paint to formulate a gray paint. Even after stored for a week, the gray paint was still in a homogeneous form without any color separation. Comparative Example 11 A paint was formulated in a similar manner as in Example 55 except that the same CB pigment was used without surface treatment with Dispersant 10. The paint was ranked as in Example 55. The paint had high viscosity, and in the form of a mixed paint with a white paint, the CB pigment underwent separation and settling through coagulation. Example 56 Eight (8) parts of Dispersant 11 were dissolved in 100 parts of an aqueous solution which contained 5 parts of glacial acetic acid. The resultant solution was added to a slurry of C.I. pigment black 7 (CB pig- ment content: 100 parts), followed by stirring for 60 minutes. A 10% aqueous solution of sodium hydroxide was then gradually added to adjust the pH of the system to 8.5. After the mixture was stirred for further 30 minutes, the resulting solid matter was collected by filtration, washed, dried at 90°C and then ground, whereby 105 parts of black pigment powder surface- treated with the dispersant were obtained. The thus-obtained surface-treated CB pigment was dispersed in a commercial acrylic lacquer by a beads mill, whereby a black paint having a CB pigment content of 13% was formulated. The paint was adjusted in vis- cosity with a lacquer thinner and was spray-painted on an iron plate. A plate coated in a black color and having a dry film thickness of 32 µm was obtained. It was excellent in vividness, and showed a high degree of gloss. Comparative Example 12 A paint was formulated in a similar manner as in Example 56 except that the same CB pigment was used without surface treatment with Dispersant 11. The vis- cosity was adjusted likewise, and the paint was ranked as in Example 56. The surface of a coating on a plate coated in a black color was not smooth, and its gloss was low. WE CLAIM 1. A dispersant for organic pigments, comprising a compound represented by the following formula (I): Wherein X and X' each independently represent a hydrogen atom, a hydroxyl group, an alkoxy group, a primary, secondary or tertiary amino group, or an acylamino group; Y represents an anthraquinonylamino, phenylamino or phenoxy group having a hydrogen atom, a hydroxyl group, an alkoxy group, a primary, secondary or tertiary amino group, or an acylamino group at the 4-position or 5-posKion thereof; A and B each independently represent an attcyl group, a cycloalkyl group or an aryl group, and at least one of A and B has at least one substituent group containing a basic nitrogen atom; and Z represents a hydrogen atom, a cyano group, a halogen atom, an alkyl group, an alkoxy group, a nitro group, a benzoylamino group or a 3-benzoyl group, and said 3-benzoyl group may be fused together with X to form an acridone ring. 2. A dispersant as claimed in claim 1, wherein said at least one substituent group containing said basic nitrogen atom is a primary, secondary or tertiary amino group, a quaternary ammonium group or a pyridinium group; and, when two or more substituent groups each of which contains said basic nitrogen group exist, said two or more substituent groups may be the same or different. 3. A dispersant as claimed in claim 1, wherein said compound represented by the formula (i) is represented by the following formula (1): Wherein X, X', Y and Z have the same meanings as defined above; R1 to R4 may be the same or different and each independently represent a substituted or un-substttuted atkyl or cycloalkyl group, and R1 and R2 and/or R3 and R4 may be fused together with the adjacent nitrogen atom thereof to form a heterocyclic ring which may additionally contain a further nitrogen atom, an oxygen atom or a sulfur atom; and R5 and R8 each independently represent an alkylene group, a cyctoalkylene group or an arylene group. 4. A dispersant as claimed in claim 1, wherein said compound represented by the formula (I) is represented by the following formula (2): Wherein X, X', Y and Z have the same meanings as defined above; R1 to R4 may be the same or different and each independently represent a substituted or un-substituted adcyl or cycloalkyl group, and R1 and R2 and/or R3 and R4 may be fused together with the adjacent nitrogen atom thereof to form a heterocyclic ring which may additionally contain a further nitrogen atom, an oxygen atom or a sulfur atom; and n and m each independently stand for an integer of from 2 to 30. 5. A dispersant as claimed in claim 1, wherein said compound represented by the formula (I) is represented by the following formula (3): Wherein X and X' each independently represent a hydrogen atom or a benzoylamino group; Z represents a hydrogen atom; R1 to R4 may be the same or different and each independently represent a methyl group or an ethyl group; and n and m each independently stand for 2 or 3. A pigments dispersion for the production of writing. A dispersant for organic pigments, comprising a compound represented by the following formula (I): Wherein X and X' each independently represent a hydrogen atom, a hydroxyl group, an alkoxy group, a primary, secondary or tertiary amino group, or an acylamino group; Y represents an anthraquinonylamino, phenylamino or phenoxy group having a hydrogen atom, a hydroxyl group, an alkoxy group, a primary, secondary or tertiary amino group, or an acylamino group at the 4-position or 5- position thereof; A and B each independently represent an alkyl group, a cycloalkyl group or an aryl group, and at least one of A and B has at least one substituent group containing a basic nitrogen atom; and Z represents a hydrogen atom, a cyano group, a halogen atom, an alkyl group, an alkoxy group, a nitro group, a benzoylamino group or a 3-benzoyl group, and said 3-benzoyl group may be fused together with X to form an acridone ring.

Full Text

PIGMENT DISPERSANTS, PIGMENT DISPERSIONS
AND WRITING OR RECORDING PIGMENT INKS
BACKGROUND OF THE INVENTION
a) Field of the Invention
This invention relates to dispersants for organic
pigments (hereinafter simply referred to as "pig-
ments"), pigment dispersions and writing or recording
pigment inks, and more specifically to pigment dis-
persants and also to pigment dispersions making use of
the pigment dispersants, having excellent fluidity,
dispersion stability, storage stability and the like
and suited especially for the production of writing or
recording pigment inks.
b) Description of the Related Art
Marking inks for use in writing instruments,
which make use of bundled fiber tips or felt tips, have
conventionally been made of resins, pigments and sol-
vents, and as the pigments, dyes have been employed.
As the solvents, ester or aromatic solvents have been
used from the standpoint of solubility for the resins
and also solubility for the dyes.
It is however desired to avoid use of aromatic
solvents, because they give deleterious effects on the
health of workers (organic solvent intoxication) and
they themselves are air pollutants. Although there is
a move toward water-based writing inks, solvent-based
maker pens are still employed widely. This can be at-
tributed to the excellent writing performance of
solvent-based inks on plastic films such as poly-
ethylene films and also to the superb drying character-
istics of the solvent-based inks shortly after written
on plastic films.
Ink-jet printing, on the other hand, is a digital
printing controlled by a computer. Printing informa-
tion signals are supplied to a printer directly from
the computer, so that no plate-making is needed. Ink-
jet printing is therefore suited particularly for the
printing of various images in small numbers of copies,
and recent advancements in ink-jet printers have made
it possible to perform printing of a variety of highly-
detailed large images.
Ink-jet printing inks are required to have low
viscosity and excellent stability. There are organic-
solvent-based inks making use of dyes, but as pigment-
type inks, water-based inks are used because ink-jet
printing inks making use of pigments involve technical
difficulties. However, water-based inks contain, as
vehicles, resins at extremely low concentrations so
that good color developments are not available. Water-
based inks are also accompanied by a problem of adhe-
sion to plastic films. Under these circumstances,
there is a strong desire for the development of
alcohol-based ink-jet printing inks making use of pig-
ments and assuring good color developments.
Incidentally, as is observed from paints and the
like, the conventional technology expects much on the
dispersing power of a resin for a pigment upon dispers-
ing the pigment on a resin solution. When the dispers-
ing power of the resin is insufficient for the pigment,
a pigment dispersant (pigment treatment) (hereinafter
simply referred to as "a pigment dispersant) has been
employed. In general paints, sufficient dispersion of
pigments is feasible with conventional dispersants.
Compared with paints, however, writing or record-
ing pigment inks are required to have extremely low
viscosity and in addition, to have an extremely high
degree of dispersion of pigments. Despite these re-
quirements, use of conventional resins and dispersants
is unable to achieve sufficient dispersion of pigments
or leads to changes in the viscosity of pigment disper-
sions along the passage of time due to desorption of
the dispersant from the pigments and insufficient com-
patibility between the pigments and the resins, thereby
making it extremely difficult to obtain pigment disper-
sions which meet the property and performance require-
ments .
If an alcoholic solvent such as ethanol can be
used as a solvent in an organic-solvent-based pigment
ink, deleterious effects on the health of users of
writing instruments and people studying or working in
the same environment as the users can be reduced, the
problem of air pollution can be lessened owing to the
avoidance of an organic solvent, and further, the prob-
lems of drying characteristics and wetting to plastic
films, said problems being inherent to water-based
inks, can also be eliminated. Moverover, alcoholic
solvents are resources reproducible in the natural
world so that use of such solvents is preferred. None-
theless, with resins soluble in conventionally-known
alcoholic solvents, it is still extremely difficult to
obtain pigment inks satisfactory in the requirements
for low viscosity, high dispersion and high dispersion
stability even if dispersants are used.
SUMMARY OF THE INVENTION
An object of the present invention is therefore
to provide a dispersant which is excellent in the dis-
persibility of pigments and permits production of a
pigment dispersion excellent in the stability of vis-
cosity. Another object of the present invention is to
provide a pigment dispersion, writing ink or recording
ink, which is using a pigment as a coloring matter,
contains a resin - which is soluble in an organic sol-
vent, especially an alcoholic solvent - in a sufficient
amount relative to the pigment, has a low viscosity,
good pigment dispersibility and excellent viscosity
stability, and gives less deleterious effects on the
health of a user of a writing instrument or recording
apparatus and people studying or working in the same
environment as the user.
To achieve the above-described objects, the pres-
ent invention provides an dispersant for organic pig-
ments, comprising a compound represented by the follow-
ing formula (I):
wherein X and X' each independently represent a
hydrogen atom, a hydroxyl group, an alkoxy group, a
primary, secondary or tertiary amino group, or an acylamino
group; Y represents an anthraquinonylamino, phenylamino
or phenoxy group having a hydrogen atom, a hydroxyl
group, an alkoxy group, a primary, secondary or
tertiary amino group, or an acylamino group at the 4-
position or 5-position thereof; A and B each indepen-
dently represent an alkyl group, a cycloalkyl group or
an aryl group, and at least one of A and B has at least
one substituent group containing a basic nitrogen atom;
and Z represents a hydrogen atom, a cyano group, a
halogen atom, an alkyl group, an alkoxy group, a nitro
group, a benzoylamino group or a 3-benzoyl group, and
the 3-benzoyl group may be fused together with X to
form an acridone ring; a pigment dispersion comprising
an organic pigment, a dispersant, a film-forming resin
and an organic solvent, wherein the dispersant is the
above-described dispersant; a writing or recording pig-
ment ink comprising the dispersion; and a writing in-
strument or recording apparatus comprising the ink (the
pigment dispersion and the writing ink or recording ink
will hereinafter be collectively called "the ink").
The term "at least one substituent group contain-
ing a basic nitrogen atom" as used herein may mean a
primary, secondary or tertiary amino group, a
quaternary ammonium group or a pyridinium group, with a
tertiary amino group being particularly preferred.
The dispersant according to the present invention
is useful as a dispersant for a variety of
conventionally-Known pigments, especially as a dis-
persant for various pigments used as coloring matters
in inks, various paints, various printing inks, various
pigment printing agents and synthetic resins. In par-
ticular, use of the dispersant according to the present
invention by adding it as a dispersant to red, green
yellow and purple inks makes it possible to stably pro-
duce low-viscosity inks and eventually to obtain ex-
cellent inks.
DETAILED DESCRIPITION OF THE INVENTION
AND PREFERRED EMBODIMENTS
The present invention will hereinafter be de-
scribed in further detail based on certain preferred
embodiments. Dispersants according to the present in-
vention are useful as dispersants for a variety of
conventionally-known pigments used as coloring matters
in various paints, various printing inks, various pig-
ment printing agents and synthetic resins. An espe-
cially useful application is an application as dis-
persants for pigments in inks. Accordingly, the pres-
ent invention will hereinafter be described by taking
inks as representative examples.
The dispersants according to the present inven-
tion can be prepared by the preparation process dis-
closed, for example, in JP 46-33232 B, JP 46-332 33 B. or
JP 46-34518 B. or a process similar to the preparation
process. As an example, a dispersant can be obtained
by reacting 1 mole of l-amino-5-benzoylaminoanthra-
quinone, 1 mole of aniline or phenol and 1 mole of
cyanuric chloride at 130 to 160°C for 2 to 6 hours in
an inert solvent such as o-dichlorobenzene, adding 1
mole of a polyamine containing at least one secondary
amino group and at least one tertiary amino group and
containing no primary amino group, and then reacting
them at 150 to 170°C for 3 to 4 hours.
Illustrative of the "polyamine containing at
least one secondary amino group and at least one
tertiary amino group and containing no primary amino
group" employed in the above-described process are:
N, N, N'-trimethy1-ethylenediamine,
N,N-dimethyl-N'-ethyl-ethylenediamine,
N, N-diethyl-N'-methyl-ethylenediamine,
N,N-dimethyl-N'-ethyl-propylenediamine,
N,N,N'-trimethy1-propylenediamine,
N,N,N'-triethyl-propylenediamine,
N, N, N ' -trimethy1-hexamethylenediamine,
N, N-diethyl-N"-methyl-p-phenylenediamine,
Among the dispersants according to the present
invention available by the above-described processes,
preferred dispersants are compounds represented by the
following formula (1), more preferred dispersants are
compounds represented by the formula (2) , and particu-
larly preferred dispersants are compounds represented
by the following formula (3):
wherein X, X', Y and Z have the same meanings as
defined above; Rx to R4 may be the same or different
and each independently represent a substituted or un-
substituted alkyl or cycloalkyl group, and R1 and R2
and/or R3 and R4 may be fused together with the ad-
jacent nitrogen atom thereof to form a heterocyclic
ring which may additionally contain a further nitrogen
atom, an oxygen atom or a sulfur atom; and R5 and R6
each independently represent an alkylene group, a
cycloalkylene group or an arylene group.
wherein X, X', Y, Z and R1 to R4 have the same meanings
as defined above; and n and m each independently stand
for an integer of from 2 to 30.
Incidentally, the aminoacyl groups in the above-
described formula (I) and the above-described formulas
(1) to (2), are groups represented by -NHCOR, in which
R is a phenyl group, a methyl group, an ethyl group, a
propyl group, a butyl group, or the like.
wherein X and X' each independently represent a
hydrogen atom or a benzoylamino group; Z represents a
hydrogen atom; R1 to R4 may be the same or different
and each independently represent a methyl group or an
ethyl group; and n and m each independently stand for 2
or 3.
Specific examples of preferred dispersants in the
present invention can include, but are not limited to,
the followings in which X represents a benzoylamino
and the quaternary ammonium compounds of Specific Exam-
ples 1-6, 9-14 and 17-19 and the pyridinium compounds
of Specific Examples 7-8 and 15-16.
Inks according to the present invention are
formed of the above-described dispersants, pigments,
film-forming resins and organic solvents.
Conventionally-known pigments are all usable as pig-
ments in the present invention. For example, pigments
such as azo pigments, condensed azo pigments, anthra-
quinone pigments, perylene/perinone pigments, indigo-
thioindigo pigments, isoindolinone pigments, azomethine
pigments, azomethineazo pigments, quinacridone pig-
ments, phthalocyanine blue, dioxazine violet, aniline
black and carbon black can be used. Particularly
preferred pigments can include C.I. pigment red
(hereinafter abbreviated as "P-R.") 177, P.R. 254, P.R.
242, C.I. pigment green (hereinafter abbreviated as
"P.G.") 36, C.I. pigment blue (hereinafter abbreviated
as "P.B.") 15:2, P.B. 15:6, P.B. 60, C.I. pigment yel-
low (hereinafter abbreviated as "P.Y.") 138, P.Y. 185,
P.Y. 150, P.Y. 139, C.I. pigment violet 23, C.I. pig-
ment black (hereinafter abbreviated as "P.BL." 6, P.BL.
7.
Conventionally-known organic solvents employed in
various paints, coating formulations, printing inks and
the like are all usable as organic solvents in the
present invention. When using inks according to the
present invention as inks for writing instruments or
recording apparatuses, use of alcoholic solvents is
preferred. As alcoholic solvents, solvents containing
alcohols the boiling points of which are 150°C or lower
are preferred. Alcohols amount to at least 10 wt.%,
preferably to 50 to 100 wt.% of alcoholic solvents.
Preferred examples of alcohols can include
ethanol, propanol, methoxypropanol, ethoxypropanol, and
propyloxyethanol. They can be used either singly or in
combination. Solvents other than these alcohols can
also be used to extents not contrary to the spirit of
the present invention. For example, ethyl acetate,
propyl acetate, cyclohexane, methylcyclohexane, ethyl-
cyclohexane, methyl ethyl ketone, methyl propyl ketone
and the like can be used in combination.
The film-forming resin (hereinafter simply
referred to as a "resin") employed in the present in-
vention is required to be soluble in the above-
described organic solvent, especially the alcoholic
solvent descried above. Such a resin comprises, as
constituent monomers, an addition-polymerizing monomer
containing a carboxyl group, a hydroxy1 group or an
amido group and a monomer addition-polymerizable with
the addition-polymerizing monomer. A description will
hereinafter be made about the monomers which make up
the resin for use in the present invention.
Examples of the carboxyl-containing monomer can
include acrylic acid and methacrylic acid; fumaric
acid, maleic acid, itaconic acid, alkyl monoesters
thereof, and hydroxyalkyl monoesters thereof; and
monoesters between hydroxyalkyl (meth)acrylates, such
as hydroxyethyl (raeth)acrylate and hydroxypropyl
(meth)acrylate, and dibasic acids, for example, suc-
cinic anhydride, phthalic anhydride and cyclohexane-
dicarboxylic acid anhydride. Incidentally, acrylic
acid and methacrylic acid will be called (meth) acrylic
acid in the present invention.
Examples of the hydroxy1-containing monomer can
include hydroxyalkyl (meth)acrylates, for example,
hydroxyethyl (meth)acrylate and hydropropyl
(meth)acrylate; esters of monoesters between the above-
described hydroxyalkyl (meth)acrylates and dibasic
aqids with dihydroxyalkyl compounds, for example,
monoesters of monoesters between hydroxyethyl
(meth) acrylate and hydroxypropyl (meth) acrylate and
succinic acid, phthalic acid and cyclohexanecarboxylic
acid with dihydroxyalkyl compounds such as ethylene
glycol and propylene glycol. The carbon numbers of the
alkyl groups in the above-described carboxyl- and
hydroxyl-containing monomers range from about 1 to 12.
Examples of the amido-containing monomer can in-
clude (meth)acrylamides and N-substituted (meth)acryl-
amides, for example, (meth)acrylic butoxymethylamide,
N-tert-butylacrylamide, N-tert-butylmethacrylamide,
diacetoneacrylamide, N-isopropylacrylamide, N,N-
dimethylacrylamide, N,N-diethylacrylaraide, N-methylol-
(meth)acrylamide, and N-alkyloxyethyl (meth)acrylamide.
In addition to the above-described monomers,
addition-polymerizing monomers copolymerizable with the
above-described respective monomers can be used to ex-
tents soluble in the alcoholic solvent in order to im-
part waterproofness, flexibility and/or other physical
properties to the resin. Examples of such monomers can
include (meth)acrylate esters, for example, methyl
(meth)aerylate, ethyl (meth)acrylate, propyl
(meth)acrylate, butyl (meth)acrylate, octyl
(meth)acrylate, lauryl (meth)acrylate, stearyl
(meth)acrylate, cyclohexyl (meth)acrylate, benzyl
(meth)acrylate, isobornyl (meth)acrylate, and tetraful-
furyl (meth)acrylate; styrene and styrene derivatives,
for example, a-methylstyrene; dialkyl esters of dibasic
acids, for example, dialkyl maleates, dialkyl
fumarates, and dialkyl itaconates; and vinyl acetate,
and (roeth)acrylonitrile.
The resin for use in the present invention can be
obtained by using the above-described monomers and
copolymerizing them, for example, by suspension
polymerization or solution polymerization, which uses
an alcoholic solvent, in the presence or absence of a
conventionally-known radical polymerization initiator.
As a resin for use in the present invention, it is
preferred to use a resin in which a monomer between an
alkyl (meth) acrylate and a dibasic acid - said monomer
being represented by the following formula: CH2=C(R1)-
COO-R2-0-CO-R3-COOH in which R1 represents a hydrogen
atom or a methyl group, R2 represents an alkylene chain
which contains 2 to 6 carbon atoms and may contain a
branched chain, R3 represents an alkylene group which
may contain a branched chain or unsaturated group - is
copolymerized at least a part of a copolymer. A blend
of the copolymer with a copolymer free of the above-
described specific monomers may also be used.
Whichever resin is used, it is preferred to contain
units of a monoester monomer between hydroxyalkyl
(meth) acrylate and a dibasic acid in a proportion of
from 1 to 50 wt.%, preferably from 3 to 4 0 wt.% based
on the whole resin. If the content of the monomer
units is too low, the resin is not very effective for
dispersing pigments. If the content of the monomer
units is too high, on the other hand, writing matter or
printed matter has lowered alkali resistance. It is
therefore not preferred to contain the monomer units
outside the above range.
To obtain the resin by copolymerizing a mixture
of the above-described monomers, the monoester of the
hydroxyalkyl (meth)acrylate and the dibasic acid may
account preferably for 1 to 50 wt.%, more preferably
for 3 to 40 wt.% of the monomer mixture. The propor-
tion (s) of other monomer(s) can be suitably determined
such that the resulting resin is soluble in the al-
coholic solvent and can satisfy its performance re-
quirements, and no particular limitation is imposed on
their proportions. The number average molecular weight
of the resin (the number average molecular weight as
obtained by measuring the resin by GPC and converting
the data with reference to the corresponding data of
standard polystyrene) ranges generally from 2,000 to
100,000, preferably from 2,000 to 50,000. The acid
value of the resin ranges generally from 0.5 to 300
mgKOH/g, preferably from 5 to 180 mgKOH/mg.
The ink according to the present invention can be
produced in a similar manner as in the production of
conventional inks and paints by using the above-
described pigment, dispersant, film-forming resin and
organic solvent, and no particular limitation is im-
posed on the production method itself. Illustrative
productions methods can include a method in which the
pigment, subsequent to its advance treatment with the
dispersant, is dispersed in a solution of the resin in
an alcoholic solvent; and a method in which the un-
treated pigment and the dispersant are mixed with the
resin solution and the pigment is subjected to disper-
sion processing in a disperser.
When the method that the pigment, subsequent to
its advance treatment with the dispersant, is dispersed
in the solution of the resin in the alcoholic solvent
is adopted, the treatment of the pigment can be prac-
ticed, for example, as will be described next. (1)
Subsequent to dissolution of the pigment and the dis-
persant in sulfuric acid or the like, the resultant
solution is poured into water. The thus-obtained mix-
ture is alkalinized to have both of the pigment and
dispersant precipitated as a solid solution. The solid
solution is collected by filtration, washed with water,
dried and then ground, whereby the pigment is obtained
in a treated form. (2) The dispersant is converted
into a salt with sulfuric acid, hydrochloric acid,
acetic acid or the like. The salt is mixed with the
pigment in water and, if necessary, the resultant mix-
ture is subjected to dispersion processing in a dis-
perser to have the dispersant adsorbed on pigment sur-
faces. The thus-treated pigment is caused to
precipitate under alkaline condition, collected by fil-
tration, washed with water, dried and then ground,
whereby the pigment is obtained in the treated form.
(3) The dispersant is dissolved in a liquid organic
acid such as acetic acid, followed by the addition of
the pigment. After the dispersant is allowed to be ad-
sorbed on pigment surfaces with optional dispersing
processing in a disperser, the thus-treated pigment is
collected by filtration, washed with an alkaline solu-
tion, washed with water, dried and then ground, whereby
the pigment is obtained in the treated form. The
treated pigment obtained as described above is dis-
persed in the solution of the resin in an alcoholic
solvent to produce the ink of the present invention.
When the method that the untreated pigment and
the dispersant are mixed with the resin solution and
the pigment is subjected to dispersion processing in a
disperser is adopted, the pigment and the dispersant
are added to the solution of the resin in the alcoholic
solvent and subsequent to optional provisional agita-
tion, the mixture is dispersed in a disperser to obtain
an ink. No particular limitation is imposed on the
disperser which can be used in the present invention.
Examples can include a kneader, an attritor, a ball
mill, a sand mill and a horizontal disperser with tum-
bling means contained therein, said sand mill and
horizontal disperser making use of glass, zircon or the
like, and a colloid mill. Upon using the dispersant-
treated pigment, it is also possible to further dis-
perse the dispersant-treated pigment in a solid resin
to obtain pigment chips and then to dissolve the pig-
ment chips in an alcoholic solvent to obtain an ink.
Subsequent to the dissolution of the pigment chips, a
resin may be added as needed.
Pigment chips can be obtained, for example, by
one of the following methods: (1) A solid resin ob-
tained by suspension polymerization or a solid resin
collected from a resin solution obtained by solution
polymerization and a dispersant-treated pigment are
kneaded under heat by using a kneader, a Banbury mixer,
a mixing roll, a three-roll mill or the like either
singly or in combination such that the pigment is dis-
persed in the resin. The resultant pigment-dispersed
resin is then ground or chopped to obtain chips. (2) A
solution of a resin in a water-soluble solvent and a
presscake of a dispersant-treated pigment are mixed in
a kneader, followed by heating to the softening point
of the resin or higher to remove water. If necessary,
the pigment is dispersed by using a three-roll mill, an
extruder or the like. The resultant pigment-dispersed
resin is ground or chopped to obtain pigment chips.
(3) A presscake of a dispersant-treated pigment and a
solid resin are subjected to flushing at the softening
temperature of the resin or higher.
In the ink according to the present invention,
the above-described dispersant may be used generally in
a proportion of from 0.5 to 50 parts by weight,
preferably in a proportion of from 1 to 30 parts by
weight per 100 parts by weight of the pigment. On the
other hand, the pigment may be used generally in a pro-
portion of from 5 to 500 parts by weight per 100 parts
by weight of the resin.
The concentration of the pigment in the ink ac-
cording to the present invention may be from 0.3 to 50
wt.% in general, with 0.5 to 30 wt.% being preferred,
although it varies depending on the pigment. The vis-
cosity of the ink may range generally from 1 to 50
mPa.s, preferably from 2 to 30 mPa.s. Depending on
the construction of the writing instrument, a viscosity
lower than 7 mPa.s may be required in some instances.
It is particularly important for an ink to be equipped
with excellent stability in viscosity along the passage
of time. Owing to the use of the above-described dis-
persant and resin along with a pigment, the ink accord-
ing to the present invention has been imparted with ex-
cellent time-dependent stability in viscosity.
A variety of additives can also be added to the
ink of the present invention. Illustrative of such ad-
ditives are fastness improvers such as ultraviolet ab-
sorbers and antioxidants; anti-settling agents; release
agents and releasability improvers; perfumes and
antimicrobial agents; plasticizers; and drying in-
hibitors. If necessary, one or more dyes can be added
further. As a resin, a resin which has compatibility
with the resin for use in the present invention may
also be used in combination to an extent not lowering
the dispersion stability of the pigment.
In general, the thus-obtained ink can be used as
is. It is however preferable to process the ink fur-
ther in a centrifugal separator or an ultracentrifugal
separator or through a filter, because removal of
coarse particles of the pigment, which may exist in a
trace amount in some instances, makes it possible to
heighten the reliability of the writing instrument or
recording apparatus.
The writing instrument according to the present
invention can be obtained by filling the ink of this
invention, which has been obtained as described above,
in a casing equipped with a porous tip. No particular
limitation is imposed on the casing insofar as it has a
size and shape convenient for writing as in the case of
a variety of conventional writing instruments fitted
with porous tips. The material of the casing, includ-
ing its cap, can be a metal, a plastic or a composite,
material thereof insofar as it is practically free from
solvent permeation.
No limitation is imposed on the structure or
material of the porous tip insofar as it allows the ink
to move from the interior of the casing to the free end
of the tip as writing proceeds. However, excellent
writing characteristics, durability and solvent
resistance are required. Usable examples of fibers of
bundled fiber tips and felt tips can include synthetic
fibers such as polyester, polypropylene, nylon,
polyacrylonitrile and vinylon fibers; cellulose and
cellulose-derived regenerated fibers; and natural
fibers such as wool, silk and cotton. Usable examples
of open-cell foamed plastic products can include rigid
or flexible urethane resin foams, foams of acetalized
polyvinyl alcohol, and foamed of regenerated fibers.
Usable examples of ink-occluding members can include
bundles fibers, felted fibers, knitted fibers, and
open-cell foamed plastic products.
In the above description, inks making use of the
dispersants according to the present invention have
been referred to as representative examples. The pres-
ent invention is however not limited only to inks. For
example, the dispersants according to the present in-
vention are useful as dispersants for a variety of
conventionally-known pigments, and are useful as dis-
persants for various pigments employed as coloring mat-
ters in diverse paints, printing inks, pigment printing
agents, synthetic resins and the like.
The present invention will next be described more
specifically by Examples and Comparative Examples, in
which the designations of "part" or "parts" and "%" are
all by weight.
Example 1
Added to 600 parts of o-dichlorobenzene were 62
parts of 1-aminoanthraquinone and 25 parts of cyanuric
chloride, followed by stirring at 130°C for 5 hours.
After cooling, 50 parts of N,N,N",N"-tetraethyl-
diethylenetriamine were added further, and the
resultant mixture was stirred at 170°C for 3 hours.
Subsequent to filtration, the thus-obtained filtercake
was washed with ethanol and then dried, whereby the
above-described specific example (1) was obtained as
Dispersant 1.
Example 2
In a similar manner as in Example 1, the above-
described specific example (2) was obtained as Dis-
persant 2 by successively subjecting l-aminoanthra-
quinone and 3,3•-iminobis(N,N-diroethylpropylamine) to
condensation reactions with cyanuric chloride.
Example 3
In a similar manner as in Example 1, the above-
described specific example (3) was obtained as Dis-
persant 3 by successively subjecting 1-aminoanthra-
quinone and 3-ethyl-10-methyl-3,6,10-triazaundecane to
condensation reactions with cyanuric chloride.
Example 4
In a similar manner as in Example 1, the above-
described specific example (4) was obtained as Dis-
persant 4 by successively subjecting l-amino-5-
benzoylaminoanthraquinone and 3,3'-iminobis(N,N-
dimethylpropylamine) to condensation reactions with
cyanuric chloride.
Example 5
In a similar manner as in Example 1, the above-
described specific example (5) was obtained as Dis-
persant 5 by successively subjecting l-amino-5-
benzoylaminoanthraquinone, aniline and 3,3'-imirio-
bis(N,N-dimethylpropylamine) to condensation reactions
with cyanuric chloride.
Example 6
In a similar manner as in Example 1, the above-
described specific example (6) was obtained as Dis-
persant 6 by successively subjecting 1-arainoanthra-
quinone and 5,13-di(n-butyl)-5,9,13-triazaheptadecane
to condensation reactions with cyanuric chloride.
Example 7
In a similar manner as in Example 1, the above-
described specific example (7) was obtained as Dis-
persant 7 by successively subjecting 1-aminoanthra-
quinone and 2,2'-dipicolylamine to condensation reac-
tions with cyanuric chloride.
Example 8
In a similar manner as in Example 1, the above-
described specific example (8) was obtained as Dis-
persant 8 by successively subjecting 1-aminoanthra-
guinone and 3,3'-dipicolylamine to condensation reac-
tions with cyanuric chloride.
Example 9
In a similar manner as in Example 1, the above-
described specific example (9) was obtained as Dis-
persant 9 by successively subjecting l-amino-4-
benzoylaminoanthraquinone and N,N,l,N,,-tetraethyl-
diethylenetriamine to condensation reactions with
cyanuric chloride.
Example 10
In a similar manner as in Example 1, the above-
described specific example (10) was obtained as Dis-
persant 10 by successively subjecting l-amino-4-
benzoylaminoanthraquinone and 3,3'-iminobis(N,N-
dimethylpropylamine) to condensation reactions with
cyanuric chloride.
Example 11
In a similar manner as in Example 1, the above-
described specific example (11) was obtained as Dis-
persant 11 by successively subjecting l-amino-4-
benzoylaminoanthraquinone and 3-ethyl-10-methyl-3,6,10-
triazaundecane to condensation reactions with cyanuric
chloride.
Example 12
In a similar manner as in Example 1, the above-
described specific example (12) was obtained as Dis-
persant 12 by successively subjecting l-amino-4,5-
dibenzoylaminoanthraquinone and 3,3•-iminobis(N,N-
dimethylpropylamine) to condensation reactions with
cyanuric chloride.
Example 13
In a similar manner as in Example 1, the above-
described specific example (13) was obtained as Dis-
persant 13 by successively subjecting l-amino-4-
benzoylaminoanthraquinone, aniline and 3,3'-imino-
bis(N,N-dimethylpropylamine) to condensation reactions
with cyanuric chloride.
Example 14
In a similar manner as in Example 1, the above-
described specific example (14) was obtained as Dis-
persant 14 by successively subjecting l-araino-4-
benzoylaminoanthraquinone and 5,13-di(n-butyl)-5,9,13-
triazaheptadecane to condensation reactions with
cyanuric chloride.
Example 15
In a similar manner as in Example 1, the above-
described specific example (15) was obtained as Dis-
persant 15 by successively subjecting l-araino-4-
benzoylaminoanthraquinone and 2,2' -dipicolylamine to
condensation reactions with cyanuric chloride.
Example 16
In a similar manner as in Example 1, the above-
described specific example (16) was obtained as Dis-
persant 16 by successively subjecting l-amino-4-
benzoylaminoanthraquinone and 3,3' -dipicolylamine to
condensation reactions with cyanuric chloride.
Example 16-2
In a similar manner as in Example 1, the above-
described specific example (17) was obtained as Dis-
persant 17 by successively subjecting l-amino-4-
hydroxyanthraquinone and 3 , 3 '-iminobis(N,N-dimethyl-
propylamine) to condensation reactions with cyanuric
chloride.
Example 16—3
In a similar manner as in Example 1, the above-
described specific example (18) was obtained as Dis-
persant 18 by successively subjecting l-amino-4-
methoxyanthraquinone and 3,3'-iminobis(N,N-dimethyl-
propylamine) to condensation reactions with cyanuric
chloride.
Example 16-4
In a similar manner as in Example 1, the above-
described specific example (19) was obtained as Dis-
persant 19 by successively subjecting 1-amino-acridone-
1,2(2',4'-dichloro)acridone and 3,3'-iminobis(N,N-
dimethylpropylamine) to condensation reactions with
cyanuric chloride.
Synthesis Example of Film-Forming Resin
Charged in a polymerizer were 75 parts of
hydroxyethyl methacrylate, 2 5 parts of a-methylstyrene,
100 parts of methyl methacrylate, 75 parts of
acryloyloxyethyl phthalate, 7 5 parts of lauryl
methacrylate, 150 parts of diacetoneacrylamide, 15
parts of azobisisobutyronitrile, 550 parts of ethanol,
150 parts of methylcyclohexane and 50 parts of ethyl
acetate. A cooling coil was set, followed by
polymerization at 75°C for 10 hours. After cooling,
the resin solution was taken out of the polyraerizer.
It was provided as a resin solution. The resin content
was 40%, and the viscosity was 250 mPa.s. The number
average molecular weight of the resin was 8,600 as
measured by GPC and converted with reference to the
corresponding data of standard polystyrene, and the
acid value of the resin was 39.
Example 17
Dispersed in a horizontal disperser with tumbling
medium contained therein were 250 parts of the above-
described resin solution, 50 parts of benzidine yellow
(P.Y. 83), 4 parts of Dispersant (1) of Example 1, 536
parts of ethanol, 60 parts of methylcyclohexane and 100
parts of ethoxypropanol. Coarse particles were then
removed by ultracentrifugal separation, whereby an ink
according to the present invention was obtained. The
average particle size of the pigment was 95 nm, and the
viscosity was 3.5 mPa.s. The ink was stored at 50°C
for a week, but settling of the pigment was not ob-
served. When its viscosity was measured, it was still
3.5 mPa.s, thereby indicating no change in viscosity.
The ink was next filled in a pen casing equipped
with a bundled fiber tip, and a writing test was con-
ducted on a polyethylene film. Smooth writing was fea-
sible. Further, 20 parts of ethoxypropanol and 5 parts
of benzyl alcohol were added further to 100 parts of
the ink. Using the thus-obtained ink, printing was
performed by an ink-jet printer. Good printed matter
was obtained.
Examples 18-24
Yellow inks were obtained in a similar manner as
in Example 17 except that the dispersants of Examples
2-8 were used as dispersants, respectively. Those yel-
low inks were then ranked as in Example 17. The
results are presented in Table 1 together with the
results of Example 17. In the table, "A" indicates
good in both writing characteristics and ink-jet
printability, while "B" indicates insufficient writing
characteristics or insufficient ink-jet printability.
Comparative Example 1
A yellow ink was obtained in a similar manner as
in Example 17 except that the dispersant was not used.
The ink was ranked as in Example 17. The results are
also presented in Table 1.
Example 25
Ten (10) parts of Dispersant 2 were dissolved in
100 parts of an aqueous solution which contained 5
parts of glacial acetic acid. The resultant solution
was added to a slurry of a red pigment (P.R. 254; pig-
ment content: 100 parts), followed by stirring for 60
minutes. A 10% aqueous solution of sodium hydroxide
was then gradually added to adjust the pH of the system
to 8.5. After the mixture was stirred for further 30
minutes, the resulting solid matter was collected by
filtration, washed, dried at 90°C and then ground,
whereby 108 parts of red pigment powder surface-treated
with the dispersant were obtained.
The thus-obtained surface-treated pigment was
dispersed to a pigment content of 15% in a commercial
melamine/alkyd paint by a ball mill. The colored paint
so obtained had low viscosity, and showed fluidity sub-
stantially close to a Newtonian flow. Further, the red
paint was mixed with a commercial white melamine/alkyd
paint to formulate a pale red paint. Even after stored
for a week, the pale red paint was still in a homo-
geneous form without any color separation.
Comparative Example 2
A paint was formulated in a similar manner as in
Example 25 except that the red pigment (P.R. 2 54) was
used without surface treatment with Dispersant 2. The
paint was ranked as in Example 25. The paint had high
viscosity, and in the form of a mixed paint with a
white paint, the red pigment underwent separation and
settling through coagulation.
Example 26
Eight (8) parts of Dispersant 3 were dissolved in
100 parts of an aqueous solution which contained 5
parts of glacial acetic acid. The resultant solution
was added to a slurry of a red pigment (P.R. 254; pig-
ment content: 100 parts), followed by stirring for 60
minutes. A 10% aqueous solution of sodium hydroxide
was then gradually added to adjust the pH of the system
to 8.5. After the mixture was stirred for further 30
minutes, the resulting solid matter was collected by
filtration, washed, dried at 90°C and then ground,
whereby 105 parts of red pigment powder surface-treated
with the dispersant were obtained.
The thus-obtained pigment composition was dis-
persed in a commercial acrylic lacquer by a beads mill,
whereby a red paint having a pigment content of 13% was
formulated. The paint was adjusted in viscosity with a
lacquer thinner and was spray-painted on an iron plate.
A plate coated in a red color and having a dry film
thickness of 32 µm was obtained. It was excellent in
vividness, and showed a high degree of gloss.
Comparative Example 3
A paint was formulated in a similar manner as in
Example 26 except that the red pigment (P.R. 254) was
used without surface treatment with Dispersant 3. The
viscosity was adjusted likewise, and the paint was
ranked as in Example 26. The surface of a coating on a
plate coated in a red color was not smooth, and its
gloss was low.
Example 27
Dispersed in a horizontal disperser with tumbling
medium contained therein were 250 parts of the resin
solution prepared in the Synthesis Example of the film-
forming resin, 50 parts of cyanine blue (P.B. 15-2), 4
parts of Dispersant (9) of Example 9, 536 parts of
ethanol, 60 parts of methylcyclohexane and 100 parts of
ethoxypropanol. Coarse particles were then removed by
ultracentrifugal separation, whereby an ink according
to the present invention was obtained. The average
particle size of the pigment was 95 nm, and the vis-
cosity was 3.8 mPa.s. The ink was stored at 50°C for a
week, but settling of the pigment was not observed.
When its viscosity was measured, it was still 3.8
mPa.s and accordingly, no change took place in vis-
cosity .
The ink was next filled in a pen casing equipped
with a bundled fiber tip, and a writing test was con-
ducted on a polyethylene film. Smooth writing was fea-
sible. Further, 20 parts of ethoxypropanol and 5 parts
of benzyl alcohol were added further to 100 parts of
the ink. Using the thus-obtained ink, printing was
performed by an ink-jet printer. Good printed matter
was obtained.
Examples 28-34
Blue inks were obtained in a similar manner as in
Example 2 7 except that the dispersants of Examples 10-
16 were used as dispersants, respectively. Those blue
inks were then ranked as in Example 27. The results
are presented in Table 2 together with the results of
Example 27. In the table, "A" indicates good in both
writing characteristics and ink-jet printability, while
"B" indicates insufficient writing characteristics or
insufficient ink-jet printability.
Comparative Example 4
A blue ink was obtained in a similar manner as in
Example 28 except that the dispersant was not used.
The ink was ranked as in Example 28. The results are
also presented in Table 2.
Example 35
Ten (10) parts of Dispersant 10 were dissolved in
100 parts of an aqueous solution which contained 5
parts of glacial acetic acid. The resultant solution
was added to a slurry of a red pigment (P.R. 254; pig-
ment content: 100 parts), followed by stirring for 60
minutes. A 10% aqueous solution of sodium hydroxide
was then gradually added to adjust the pH of the system
to 8.5. After the mixture was stirred for further 30
minutes, the resulting solid matter was collected by
filtration, washed, dried at 90*C and then ground,
whereby 108 parts of red pigment powder surface-treated
with the dispersant were obtained.
The thus-obtained surface-treated pigment was
dispersed to a pigment content of 15% in a commercial
melamine/alkyd paint by a ball mill. The colored paint
so obtained had low viscosity, and showed fluidity sub-
stantially close to a Newtonian flow. Further, the red
paint was mixed with a commercial white melamine/alkyd
paint to formulate a pale red paint. Even after stored
for a week, the pale red paint was still in a homo-
geneous form without any color separation.
Comparative Example 5
A paint was formulated in a similar manner as in
Example 35 except that the red pigment (P.R. 254) was
used without surface treatment with Dispersant 10. The
paint was ranked as in Example 35. The paint had high
viscosity, and in the form of a mixed paint with a
white paint, the red pigment underwent separation and
settling through coagulation.
Example 36
Eight (8) parts of Dispersant 11 were dissolved
in 100 parts of an aqueous solution which contained 5
parts of glacial acetic acid. The resultant solution
was added to a slurry of a red pigment (P.R. 254; pig-
ment content: 100 parts), followed by stirring for 60
minutes. A 10% aqueous solution of sodium hydroxide
was then gradually added to adjust the pH of the system
to 8.5. After the mixture was stirred for further 30
minutes, the resulting solid matter was collected by
filtration, washed, dried at 90°C and then ground,
whereby 105 parts of red pigment powder surface-treated
with the dispersant were obtained.
The thus-obtained surface-treated pigment was
dispersed in a commercial acrylic lacquer by a beads
mill, whereby a red paint having a pigment content of
13% was formulated. The paint was adjusted in vis-
cosity with a lacquer thinner and was spray-painted on
an iron plate. A plate coated in a red color and hav-
ing a dry film thickness of 32 µm was obtained. It was
excellent in vividness, and showed a high degree of
gloss.
Comparative Example 6
A paint was formulated in a similar manner as in
Example 36 except that the red pigment (P.R. 254) was
used without surface treatment with Dispersant 11. The
viscosity was adjusted likewise, and the paint was
ranked as in Example 36. The surface of a coating on a
plate coated in a red color was not smooth, and its
gloss was low.
Example 37
Dispersed in a horizontal disperser with tumbling
medium contained therein were 2 50 parts of the resin
solution prepared in the Synthesis Example of the film-
forming resin, 750 parts of c.I. pigment black, 4 parts
of Dispersant (1) of Example 1, 536 parts of ethanol,
60 parts of methylcyclohexane and 100 parts of ethoxy-
propanol. Coarse particles were then removed by
ultracentrifugal separation, whereby a black ink ac-
cording to the present invention was obtained. The
average particle size of the CB pigment was 95 nra, and
the viscosity was 3.5 mPa.s. The black ink was stored
at 50°C for a week, but settling of the CB pigment was
not observed. When its viscosity was measured, it was
still 3.5 mPa.s and accordingly, no change took place
in viscosity.
The black ink was next filled in a pen casing
equipped with a bundled fiber tip, and a writing test
was conducted on a polyethylene film. Smooth writing
was feasible. Further, 20 parts of ethoxypropanol and
5 parts of benzyl alcohol were added further to 100
parts of the black ink. Using the thus-obtained black
ink, printing was performed by an ink-jet printer.
Good printed matter was obtained.
Examples 38-44
Black inks were obtained in a similar manner as
in Example 3 7 except that the dispersants of Examples
2-8 were used as dispersants, respectively. Those
black inks were then ranked as in Example 37. The
results are presented in Table 3 together with the
results of Example 37. In the table, "A" indicates
good in both writing characteristics and ink-jet
printability, while "B" indicates insufficient writing
characteristics or insufficient ink-jet printability.
Comparative Example 7
A black ink was obtained in a similar manner as
in Example 37 except that the dispersant was not used.
The ink was ranked as in Example 37. The results are
also presented in Table 3.
Example 45
Ten (10) parts of Dispersant 2 were dissolved in
200 parts of an aqueous solution which contained 5
parts of glacial acetic acid. The resultant solution
was added to a slurry of C.I. pigment black 7 (CB pig-
ment content: 100 parts), followed by stirring for 60
minutes. A 10% aqueous solution of sodium hydroxide
was then gradually added to adjust the pH of the system
to 8.5. After the mixture was stirred for further 30
minutes, the resulting solid matter was collected by
filtration, washed, dried at 90°C and then ground,
whereby 108 parts of black pigment powder surface-
treated with the dispersant were obtained.
The thus-obtained surface-treated CB pigment was
dispersed to a CB pigment content of 15% in a commer-
cial melamine/alkyd paint by a ball mill. The colored
paint so obtained had low viscosity, and showed
fluidity substantially close to a Newtonian flow. Fur-
ther, the black paint was mixed with a commercial white
melamine/alkyd paint to formulate a gray paint. Even
after stored for a week, the gray paint was still in a
homogeneous form without any color separation.
Comparative Example 8
A paint was formulated in a similar manner as in
Example 45 except that the same CB pigment was used
without surface treatment with Dispersant 2. The paint
was ranked as in Example 45. The paint had high vis-
cosity, and in the form of a mixed paint with a white
paint, the CB pigment underwent separation and settling
through coagulation.
Example 46
Eight (8) parts of Dispersant 3 were dissolved in
100 parts of an aqueous solution which contained 5
parts of glacial acetic acid. The resultant solution
was added to a slurry of C.I. pigment black 7 (CB pig-
ment content: 100 parts), followed by stirring for 60
minutes. A 10% aqueous solution of sodium hydroxide
was then gradually added to adjust the pH of the system
to 8.5. After the mixture was stirred for further 30
minutes, the resulting solid matter was collected by
filtration, washed, dried at 90°C and then ground,
whereby 105 parts of black pigment powder surface-
treated with the dispersant were obtained.
The thus-obtained surface-treated CB pigment was
dispersed in a commercial acrylic lacquer by a beads
mill, whereby a black paint having a CB pigment content
of 13% was formulated. The paint was adjusted in vis-
cosity with a lacquer thinner and was spray-painted on
an iron plate. A plate coated in a black color and
having a dry film thickness of 32 µm was obtained. It
was excellent in vividness, and showed a high degree of
gloss.
Comparative Example 9
A paint was formulated in a similar manner as in
Example 46 except that the same CB pigment was used
without surface treatment with Dispersant 3. The vis-
cosity was adjusted likewise, and the paint was ranked
as in Example 46. The surface of a coating on a plate
coated in a black color was not smooth, and its gloss
was low.
Example 4 7
Dispersed in a horizontal disperser with tumbling
medium contained therein were 250 parts of the resin
solution prepared in the Synthesis Example of the film-
forming resin, 750 parts of C.I. pigment black, 4 parts
of Dispersant (9) of Example 9, 536 parts of ethanol,
60 parts of methylcyclohexane and 100 parts of ethoxy-
propanol. Coarse particles were then removed by
ultracentrifugal separation, whereby a black ink ac-
cording to the present invention was obtained. The
average particle size of the CB pigment was 95 nm, and
the viscosity was 3.5 mPa.s. The black ink was stored
at 50°C for a week, but settling of the CB pigment was
not observed. When its viscosity was measured, it was
still 3.5 mPa.s and accordingly, no change took place
in viscosity.
The black ink was next filled in a pen casing
equipped with a bundled fiber tip, and a writing test
was conducted on a polyethylene film. Smooth writing
was feasible. Further, 20 parts of ethoxypropanol and
5 parts of benzyl alcohol were added further to 100
parts of the black ink. Using the thus-obtained black
ink, printing was performed by an ink-jet printer.
Good printed matter was obtained.
Examples 48-54
Black inks were obtained in a similar manner as
in Example 4 7 except that the dispersants of Examples
10-16 were used as dispersants, respectively. Those
black inks were then ranked as in Example 47. The
results are presented in Table 4 together with the
results of Example 47. In the table, "A" indicates
good in both writing characteristics and ink-jet
printability, while "B" indicates insufficient writing
characteristics or insufficient ink-jet printability.
Example 55
Ten (10) parts of Dispersant 10 were dissolved in
200 parts of an aqueous solution which contained 5
parts of glacial acetic acid. The resultant solution
was added to a slurry of C.I. pigment black 7 (CB pig-
ment content: 100 parts), followed by stirring for 60
minutes. A 10% aqueous solution of sodium hydroxide
was then gradually added to adjust the pH of the system
to 8.5. After the mixture was stirred for further 3 0
minutes, the resulting solid matter was collected by
filtration, washed, dried at 90°C and then ground,
whereby 108 parts of black pigment powder surface-
treated with the dispersant were obtained.
The thus-obtained surface-treated CB pigment was
«
dispersed to a CB pigment content of 15% in a commer-
cial melamine/alkyd paint by a ball mill. The colored
paint so obtained had low viscosity, and showed
fluidity substantially close to a Newtonian flow. Fur-
ther, the black paint was mixed with a commercial white
melamine/alkyd paint to formulate a gray paint. Even
after stored for a week, the gray paint was still in a
homogeneous form without any color separation.
Comparative Example 11
A paint was formulated in a similar manner as in
Example 55 except that the same CB pigment was used
without surface treatment with Dispersant 10. The
paint was ranked as in Example 55. The paint had high
viscosity, and in the form of a mixed paint with a
white paint, the CB pigment underwent separation and
settling through coagulation.
Example 56
Eight (8) parts of Dispersant 11 were dissolved
in 100 parts of an aqueous solution which contained 5
parts of glacial acetic acid. The resultant solution
was added to a slurry of C.I. pigment black 7 (CB pig-
ment content: 100 parts), followed by stirring for 60
minutes. A 10% aqueous solution of sodium hydroxide
was then gradually added to adjust the pH of the system
to 8.5. After the mixture was stirred for further 30
minutes, the resulting solid matter was collected by
filtration, washed, dried at 90°C and then ground,
whereby 105 parts of black pigment powder surface-
treated with the dispersant were obtained.
The thus-obtained surface-treated CB pigment was
dispersed in a commercial acrylic lacquer by a beads
mill, whereby a black paint having a CB pigment content
of 13% was formulated. The paint was adjusted in vis-
cosity with a lacquer thinner and was spray-painted on
an iron plate. A plate coated in a black color and
having a dry film thickness of 32 µm was obtained. It
was excellent in vividness, and showed a high degree of
gloss.
Comparative Example 12
A paint was formulated in a similar manner as in
Example 56 except that the same CB pigment was used
without surface treatment with Dispersant 11. The vis-
cosity was adjusted likewise, and the paint was ranked
as in Example 56. The surface of a coating on a plate
coated in a black color was not smooth, and its gloss
was low.
WE CLAIM
1. A dispersant for organic pigments, comprising a compound represented by
the following formula (I):
Wherein X and X' each independently represent a hydrogen atom, a
hydroxyl group, an alkoxy group, a primary, secondary or tertiary amino
group, or an acylamino group; Y represents an anthraquinonylamino,
phenylamino or phenoxy group having a hydrogen atom, a hydroxyl group,
an alkoxy group, a primary, secondary or tertiary amino group, or an
acylamino group at the 4-position or 5-posKion thereof; A and B each
independently represent an attcyl group, a cycloalkyl group or an aryl
group, and at least one of A and B has at least one substituent group
containing a basic nitrogen atom; and Z represents a hydrogen atom, a
cyano group, a halogen atom, an alkyl group, an alkoxy group, a nitro
group, a benzoylamino group or a 3-benzoyl group, and said 3-benzoyl
group may be fused together with X to form an acridone ring.
2. A dispersant as claimed in claim 1, wherein said at least one substituent
group containing said basic nitrogen atom is a primary, secondary or
tertiary amino group, a quaternary ammonium group or a pyridinium
group; and, when two or more substituent groups each of which contains
said basic nitrogen group exist, said two or more substituent groups may
be the same or different.
3. A dispersant as claimed in claim 1, wherein said compound represented
by the formula (i) is represented by the following formula (1):

Wherein X, X', Y and Z have the same meanings as defined above; R1 to
R4 may be the same or different and each independently represent a
substituted or un-substttuted atkyl or cycloalkyl group, and R1 and R2
and/or R3 and R4 may be fused together with the adjacent nitrogen atom
thereof to form a heterocyclic ring which may additionally contain a further
nitrogen atom, an oxygen atom or a sulfur atom; and R5 and R8 each
independently represent an alkylene group, a cyctoalkylene group or an
arylene group.
4. A dispersant as claimed in claim 1, wherein said compound represented
by the formula (I) is represented by the following formula (2):

Wherein X, X', Y and Z have the same meanings as defined above; R1 to
R4 may be the same or different and each independently represent a
substituted or un-substituted adcyl or cycloalkyl group, and R1 and R2
and/or R3 and R4 may be fused together with the adjacent nitrogen atom
thereof to form a heterocyclic ring which may additionally contain a further
nitrogen atom, an oxygen atom or a sulfur atom; and n and m each
independently stand for an integer of from 2 to 30.
5. A dispersant as claimed in claim 1, wherein said compound represented
by the formula (I) is represented by the following formula (3):

Wherein X and X' each independently represent a hydrogen atom or a
benzoylamino group; Z represents a hydrogen atom; R1 to R4 may be the
same or different and each independently represent a methyl group or an
ethyl group; and n and m each independently stand for 2 or 3.

A pigments dispersion for the production of writing.
A dispersant for organic pigments, comprising a compound represented by the
following formula (I):
Wherein X and X' each independently represent a hydrogen atom, a hydroxyl
group, an alkoxy group, a primary, secondary or tertiary amino group, or an
acylamino group; Y represents an anthraquinonylamino, phenylamino or phenoxy
group having a hydrogen atom, a hydroxyl group, an alkoxy group, a primary,
secondary or tertiary amino group, or an acylamino group at the 4-position or 5-
position thereof; A and B each independently represent an alkyl group, a
cycloalkyl group or an aryl group, and at least one of A and B has at least one
substituent group containing a basic nitrogen atom; and Z represents a hydrogen
atom, a cyano group, a halogen atom, an alkyl group, an alkoxy group, a nitro
group, a benzoylamino group or a 3-benzoyl group, and said 3-benzoyl group
may be fused together with X to form an acridone ring.

Documents:

177-KOL-2004-(21-11-2012)-ABSTRACT.pdf

177-KOL-2004-(21-11-2012)-ANNEXURE TO FORM 3.pdf

177-KOL-2004-(21-11-2012)-CLAIMS.pdf

177-KOL-2004-(21-11-2012)-CORRESPONDENCE.pdf

177-KOL-2004-(21-11-2012)-DESCRIPTION (COMPLETE).pdf

177-KOL-2004-(21-11-2012)-FORM-1.pdf

177-KOL-2004-(21-11-2012)-FORM-2.pdf

177-KOL-2004-(21-11-2012)-OTHERS.pdf

177-KOL-2004-(21-11-2012)-PA.pdf

177-KOL-2004-(21-11-2012)-PETITION UNDER RULE 137.pdf

177-kol-2004-abstract.pdf

177-kol-2004-claims.pdf

177-KOL-2004-CORRESPONDENCE.pdf

177-kol-2004-description (complete).pdf

177-kol-2004-form 1.pdf

177-kol-2004-form 2.pdf

177-kol-2004-form 3.pdf

177-kol-2004-form 5.pdf

177-kol-2004-priority document.pdf

177-kol-2004-specification.pdf

177-kol-2004-translated copy of priority document.pdf

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Patent Number

257074

Indian Patent Application Number

177/KOL/2004

PG Journal Number

36/2013

Publication Date

06-Sep-2013

Grant Date

30-Aug-2013

Date of Filing

12-Apr-2004

Name of Patentee

DAINICHISEIKA COLOR & CHEMICALS MFG. CO. LTD.

Applicant Address

7-6, BAKURO-CHO 1-CHOME, NIHONBASHI, CHUO-KU, TOKYO

Inventors:

#	Inventor's Name	Inventor's Address
1	SAIKATSU HIROAKI	C/O TECHNICAL RESEARCH CENTER OF DAINICHISEIKA COLOR & CHEMICALS MFG. CO. LTD. 1-9-4, HORINOUCHI, ADACHI-KU, TOKYO
2	OKAMOTO HISAO	C/O TECHNICAL RESEARCH CENTER OF DAINICHISEIKA COLOR & CHEMICALS MFG. CO. LTD. 1-9-4, HORINOUCHI, ADACHI-KU, TOKYO
3	SAKAMOTO SHIGERU	C/O TECHNICAL RESEARCH CENTER OF DAINICHISEIKA COLOR & CHEMICALS MFG. CO. LTD. 1-9-4, HORINOUCHI, ADACHI-KU, TOKYO
4	FUKUDA TETSUO	C/O TECHNICAL RESEARCH CENTER OF DAINICHISEIKA COLOR & CHEMICALS MFG. CO. LTD. 1-9-4, HORINOUCHI, ADACHI-KU, TOKYO
5	YAMAMIYA SHIRO	C/O TECHNICAL RESEARCH CENTER OF DAINICHISEIKA COLOR & CHEMICALS MFG. CO. LTD. 1-9-4, HORINOUCHI, ADACHI-KU, TOKYO
6	ABE YOSHIO	C/O TECHNICAL RESEARCH CENTER OF DAINICHISEIKA COLOR & CHEMICALS MFG. CO. LTD. 1-9-4, HORINOUCHI, ADACHI-KU, TOKYO
7	NAKAMURA MICHIEL	C/O TECHNICAL RESEARCH CENTER OF DAINICHISEIKA COLOR & CHEMICALS MFG. CO. LTD. 1-9-4, HORINOUCHI, ADACHI-KU, TOKYO
8	YAMAZAKI MITSUO	C/O TECHNICAL RESEARCH CENTER OF DAINICHISEIKA COLOR & CHEMICALS MFG. CO. LTD. 1-9-4, HORINOUCHI, ADACHI-KU, TOKYO

PCT International Classification Number

C09B 67/46

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	10371915	1998-12-28	Japan