Abstract:
There is provided a new pigment composition composed of a pigment and a dispersant wherein the dispersant is a phosphoric ester compound represented by the formula below. ##STR1## (where one or more than one of the three R&#39;s are residues of a hydroxy-carboxylic acid and/or hydroxy ester thereof; and one or two of the three R&#39;s, in case of being remained, are hydrogen atoms, cations, or residues of an alcohol excluding the above-mentioned residues.)

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates a new pigment composition and, more particularly, to a pigment composition useful as a coloring material such as paint, printing ink, or a synthetic resin colorant in which a phosphonic ester compound containing a residue of hydraxy carboxylic acid and/or hydroxy ester thereof is used as the pigment dispersant or flushing agent. 
     2. Description of the Prior Art 
     In the conventional process for producing paints and printing inks, lecithin, which is one of phospholipids, has been used both as a dispersant for dispersing a pigment into a paint vehicle or printing ink varnish, and as a flushing agent for flushing the aqueous filter cake into an oil vehicle or oil varnish. 
     Being a natural phospholipid, lecithin is liable to oxidation and rancidity which lead to deterioration and putrefaction. Thus there has been a demand for a dispersant or flushing agent which is stabler and better than lecithin. 
     In view of the above-mentioned drawbacks of the conventional dispersant or flushing agent and in order to develop a new compound which is compatible with vehicles and varnishes and also with pigments and is useful as a pigment dispersant, the present inventors carried out a series of researches which led to the finding that a phosphoric ester obtained by reacting a hydroxy carboxylic acid and/or hydroxy ester thereof with phosphoric acid exhibits outstanding properties and effects required for pigment dispersants. The present invention was completed based on this finding. 
     SUMMARY OF THE INVENTION 
     Accordingly, it is an object of the present invention to provide a pigment composition composed of a pigment and a dispersant wherein the dispersant is a phosphoric ester compound represented by the formula below. ##STR2## (where one or more than one of the three R&#39;s are residues of hydroxy carboxylic acid and/or hydroxy ester thereof; and one or two of the three R&#39;s in case of being remained, are hydrogen atoms, cations, or residues of an alcohol excluding the above-mentioned hydroxy carboxylic acid and/or hydroxy ester thereof.) 
     DETAILED DESCRIPTION OF THE INVENTION 
     The dispersant which characterizes the pigment composition of this invention is a specific phosphoric ester compound as defined above. 
     The phosphoric ester compound used in this invention can be obtained by various methods. According to a preferred method, it is obtained by reacting 1 mole of an ester-forming phosphorus compound with 3 moles, 2 moles, or 1 mole of a hydroxy carboxylic acid and/or hydroxy thereof. 
     When 1 mole of an ester-forming phosphorus compound is reacted with 3 moles of a hydroxy carboxylic acid and/or hydroxy ester thereof, there is obtained a phosphoric ester compound in which all of the three R&#39;s in the above formula are residues of a hydroxy carboxylic acid and/or hydroxy ester thereof. Also, when 1 mole of an ester-forming phosphorus compound is reacted with 2 moles or 1 mole of hydroxy carboxylic acid and/or hydroxy ester thereof, there is obtained a phosphoric ester compound in which one or two of the three R&#39;s in the above formula are residues of hydroxy carboxylic acid and/or hydroxy ester thereof. 
     Among the ester-forming phosphorus compounds that can be used in this invention are phosphorus oxychloride, phosphorus pentoxide, phosphorus trichloride, phosphoric anhydride, and acetyl phosphate. Perferable among them is phosphorus oxychloride. 
     The reaction of the above-mentioned ester-forming phosphorus compound with a hydroxy carboxylic acid and/or hydroxy ester thereof should preferably be carried out in an organic solvent which is both inert to the reactants and reaction products and solubilizes them. Examples of such organic solvents include aliphatic saturated hydrocarbons such as octane, petroleum ether, ligroin, mineral spirit, and kerosene; aromatic hydro-carbons such as benzene, toluene, and xylene; halogenated aliphatic hydrocarbons such as trichloroethane and tetrachloroethane; and chlorinated aromatic hydrocarbons such as dichlorobenzene and trichloro-benzene. They have been used for the production of polyesters. 
     In the case where a halogenated phosphorus compound such as phosphorus oxychloride is used as the ester-forming phosphorus compound, it is desirable to use as a catalyst a tertiary amine such as triethylamine; an organic base such as pyridine, 2,6-lutidine, and 1,8-diaza-bicyclo-(5.4.0)undecene-7; or an inorganic base such as oxides, hydroxides, carbonates and organic acid salts of alkali metals or alkaline earth metals. 
     In the case where one or two of the three R&#39;s in the above formula are hydrogen atoms or cations (mentioned later), a cation source mentioned later should be added to the reaction mixture to form a salt when the reaction of an ester-forming phosphorus compound with 2 moles or 1 mole of hydroxy carboxylic acid and/or hydroxy ester thereof is substantially complete, or after the hydrolysis is performed as required (in the case where a halogenated phosphorus compound is used as an ester-forming phosphorus compound). The cation source may be added before, during, or after the production of the pigment composition of this invention using the phosphoric ester compound of the above-mentioned formula, which has one or two residues of corboxylic acid and/or hydroxy ester thereof residues, with the remaining R&#39;s being hydrogen ions. 
     The preferred hydroxy-carboxylic acid used in this invention is one which has 4 to 30 carbon atoms. Examples of such hydroxycarboxylic acids include ricinoleic acid, 12-hydroxy-stearic acid, castor oil fatty acid, hydrogenated castor oil fatty acid δ-hydroxy-valeric acid, ε-hydroxy-caproic acid, p-hydroxyethyloxybenzoic acid, and 2-hydroxynaphthalene-6-carboxylic acid. They may be used individually or in combination with one another. 
     It is also possible to use, in the same manner a hydroxyl-terminated ester obtained by esterifying an alcohol the with carboxyl group of above-mentioned hydroxy-carboxylic acid. Examples of the alcohol used for the esterification are alcohols having 1 to 30 carbon atoms, such as methyl alcohol, ethyl alcohol, propyl alcohol, butyl alcohol, hexyl alcohol, octyl alcohol, decyl alcohol, dodecyl alcohol, tridecyl alcohol, hexadecyl alcohol, octadecyl alcohol, tetracosyl alcohol, hexacosyl alcohol, octadecenyl alcohol, cyclohexyl alcohol, and benzyl, alcohol. 
     The phosphoric ester compound used as a dispersant in this invention is obtained by reacting 3 moles, 2 moles, or 1 mole of the above-mentioned hydroxy corboxylic acid and/or hydroxy ester thereof with 1 mole of the above-mentioned ester-forming phosphorus compound. Where 2 moles or 1 more of the above-mentioned corboxylic acid and/or hydroxy ester thereof is reacted with 1 mole of the phosphorus compound, one or two R&#39;s other than residues of corboxylec acid and/or hydroxy ester thereof in the above-mentioned formula may be groups other than the above-mentioned corboxylic acid and/or hydroxy ester thereof, such as residue of alcohol compounds, hydrogen atoms, inorganic cations, or organic cations. Examples of the alcohol residues are the residues of ordinary alcohols such as of the avobe-mentioned alcoholes used in the esterification of hydroxy-carboxylic acid. 
     Examples of inorganic cations include alkaline metals such as sodium and potassium; polyvalent metals such as magnesium, calcium, strontium, barium, manganese, iron, cobalt, nickel, zinc, aluminum, and tin; and ammonium. Examples of organic cations include cations of primary, secondary, and tertiary monoamines and polyamines having 1 to 30 carbon atoms such as methylamine, ethylamine, propylamine, butylamine, hexylamine, octylamine, dodecylamine, octadecylamine, oleylamine, diethylamine, dibutylamine, distearylamine, triethylamine, tributylamine, dimethyloctylamine, dimethyldecylamine, dimethyldodecylamine, dimethyltetradecylamine, dimethylhexadecylamine, dimethyloctadecylamine, dimethyloleylamine, dilaurylmonomethylamine, trioctylamine, dimethylaniline, ethylenediamine, propylene diamine, hexamethylenediamine, and stearylpropylenediamine; quaternary ammoniums such as octadecyl trimethylammonium and dioctadecyl dimethylammonium; and alkanolamines such as ethanolamine, diethanolamine, triethanolamine, dimethylethanolamine, diethylethanolamine, propanolamine, and other alkanolamines obtained by adding ethylene oxide to the above-mentioned higher aliphatic amine. These amines can be used individually or in combination with one another. Where a higher aliphatic amine or ammonium derived from natural oils and fats is used as a raw material, it is possible to the mixture of amines each differing in carbon number and degree of saturation as such. 
     The above-mentioned phosphoric ester compound used in this invention comes in different forms according to the substituent group R. The ones defined below are comparatively hydrophobic dispersants adequately soluble in an organic solvent. (1) All of the three R&#39;s are residues of hydroxyl ester of hydroxyl carboxylic acid. (2) The three R&#39;s are residues of hydroxy ester of hydroxyl carboxylic acid and residues of other alcohols. (3) One or two of the three R&#39;s are cations of a higher amine. 
     On the other hand, the compound of the above-formula in which one or two of the three R&#39;s are residues of hydroxyl carboxyled acid cations selected from the alkali metals, ammonium, lower amines, and lower alkanolamines, is a comparatively hydrophilic dispersant soluble or dispersible in water or aqueous solutions. 
     The pigment used in this invention may be any known organic pigment, inorganic pigment, or extender pigment. Examples of organic pigments include phthalocyanine pigments, azo-pigments, condensed azo-pigments, anthraquinone pigments perinone pigments, perylene pigments, indigo pigments thioindigo pigments, isoindolinone pigment, azomethinazo pigments, dioxadine pigments, quinacridone pigments, aniline black pigments, triphenylmethane pigments, and carbon black. Examples of inorganic pigments include titanium oxide pigments, iron oxide pigments, iron hydroxide pigments, chromium oxide pigments, spinel type calcined pigment, lead chromate pigments, vermilion pigments, Prussian Blue, aluminum powder, and bronze powder. Examples of extender pigments include calcium carbonate, barium sulfate, silicon dioxide, and aluminum hydroxide. These pigments are used in the form of dry fine powder, aqueous filter cake, or aqueous suspension. 
     The pigment composition of this invention is prepared by compounding 100 parts by weight of the above-mentioned pigment and 1 to 300 parts by weight, preferably 3 to 150 parts by weight, of the above-mentioned phosphoric ester compound. Needless to say, these two components are incorporated with a known proper organic solvent, aqueous or oily paint vehicle, aqueous or oily printing ink varnish, aqueous or oily coating vehicle, thermoplastic resin, thermosetting resin, plasticizer, crosslinking agent, and catalyst. The resulting composition can be used as such as a paint or printing ink. These essential components and optional components can be mixed and dispersed by any known method using a ball mill, sand mill, attritor, continuous horizontal medium dispersing machine, two-roll mill, three-roll mill, pressure kneader, Banbury mixer, or extruder. 
     In the case where a pigment in the form of an aqueous filter cake or aqueous suspension is used, the pigment composition of this invention can be prepared by the flushing method. According to this method, the pigment is transferred from the aqueous phase to the organic solvent phase by mixing the pigment with the comparatively hydrophobic dispersant among the dispersant used in this invention, alone or, preferably, in the form of a solution in a hydrophobic organic solvent (which may contain a binder for ink or paint). 
     The pigment composition of this invention may be embodied in the following two forms. 
     (1) A composition containing pigments in high concentrations, which is useful as a coloring agent for printing inks, paints, coating agents, and synthetic resins. In this embodiment, the concentration of pigment is 20 to 95 wt% and the concentration of the dispersant is 1 to 300 wt% for pigment weight. 
     (2) A compobbsition useful as a paint which contains a solvent, binder resin, etc. required for paints, printing inks, and coating agents. In this embodiment, the concentration of pigment is 0.1 to 20 wt% and the concentration of the dispersant is 1 to 300 wt% for pigment weight. 
     The paint mentioned above embraces all the known paints containing pigments. Examples include automobile paints, building paints, wood paints, vehicle and machine paints, household paints, plastics paints, precoat metal paints, can paints, ship paints, anticorrosion paints, photocurable paints, electron ray curable paints electrostatic coating powder paints, and vinylsol paints. 
     The printing ink mentioned above embraces all the known printing inks. Examples include letterpress ink, lithographic ink, rotogravure ink, screen ink, newspaper ink, and flexographic ink. 
     The pigment composition of this invention may be in the form of solid or liquid. In the latter case, the medium is water, a mixture of water and hydrophilic organic solvent, or an organic solvent. Examples of organic solvents include aliphatic, alicyclic, and aromatic hydro-carbons; halogenated hydrocarbons, esters, ketones, glycol ethers, and alcohols. They are not limitative. 
     The paint vehicle, printing ink varnish, and coating agent vehicle may be any known oily or aqueous binders which are selected according to uses. Examples of the binder include long-oil alkyd resin, medium-oil alkyd resin, short-oil alkyd resin, phenol-modified alkyd resin, styrenated alkyd resin, aminoalkyd resin, oil-free alkyd resin, thermosetting acrylic resin, acryl lacquer resin, acrylpolyol resin, polyester resin, epoxy resin, butylated melamine resin, methylated melamine resin, ureamelamine resin, phenolic resin, rosin-modified phenolic resin, rosin-modified maleic acid resin, phenol-modified maleic acid resin, polyurethane resin, styrene resin, styrene-acrylic resin, styrene-diene copolymer, vinyl chloride copolymer, vinyl-acetate resin, vinyl acetate copolymer, ethylene-vinyl acetate resin, butyral resin, petroleum resin, rosin ester, maleinized rosin ester, drying oil, and boiled oil. 
     Examples of thermoplastic resins include polyvinyl chloride resin, polystyrene resin, acrylonitrile-styrene resin, acrylic resin, methacrylic-styrene resin, and polyester resin. 
     Examples of plasticizers include phthalic esters, adipic ester, sebacic esters, polyester plasticizer, and epoxidized soybean oil. 
     If necessary, the pigment composition of this invention may be used in combination with a known pigment dispersant or flushing agent such as higher aliphatic monoamine, higher aliphatic diamine, and acetate thereof and higher fatty acid salt thereof. 
     The phosphoric ester compound containing a polyester chain which is used in the present invention is not in danger of deterioration and putrefaction due to oxidation and rancidity, unlike lecithin as a natural phospholipid, which has been conventionally used as a pigment dispersant for paints, printing inks, and plastics colorants, It has good stability and produces an outstanding effect in the surface modification of pigments and the dispersion of pigments in a medium. 
     The phosphoric ester compound of this invention is readily adsorbed on the pigment surface due to the electronic attraction produced by the phosphoric ester linkage and the ester linkage contained therein and the affinity for mediums produced by the hydrocarbon chain contained therein. This adsorption improves the wettability, dispersibility, and flowability of pigments. In addition, the phosphoric ester compound is useful as a flushing agent for the aqueous filter cake of pigment. It makes the pigment surface lipophilic or hydrophobic, permitting effective flushing of pigments. 
    
    
     The invention is now described in more detail with reference to referential examples (production of the phosphoric ester compound) and working examples. (In examples, quantities are expressed as parts by weight or percent by weight.) 
     REFERENTIAL EXAMPLE 1 
     Synthesis of Phosphoric Triester Compound 
     Into a four-mouth glass reactor equipped with a stirrer, thermometer, dropping funnel, and reflux condenser and placed in a water bath were charged 50.5 parts of mixture of dodecyl alcohol esters and tridecyl alcohol esters of 12-hydroxyl stearic acid (gramequivalent:505) (1), 50.5 parts of benzene, and 9.5 parts of pyridine, followed by stirring and dissolution. The dropping funnel was filled with 5.1 parts of phosphorus oxychloride. 
     The equivalent ratio of the hydoroxy ester mixture, phosphorus oxychloride, and pyridine was 3:3:3.6. 
     While stirring and cooling the reaction mixture (below 10° C.), phosphorus oxychloride was added dropwise from the dropping funnel over 60 minutes. After addition, the reaction mixture was gradually warmed to 80° C. over 2 hours and the reaction was continued for 2 hours with stirring, followed by cooling. 
     For the removal of pyridine (as a dehydrochlorination catalyst) and pyricine hydrochloride, the reaction mixture was filtered and washed with an equal amount of deionized water, half an amount of water acidified with hydrochloric acid, and three times with half an amount of deionized water using a separatory funnel. The washed benzene layer was dried with sodium sulfate and benzene was distilled away under vacuum. Thus there was obtained a pale brown liquid reaction porduct. 
     The reaction product was identified as a phosphoric triester compound of the 12-hydroxy-stearic acid by the infrared absorption spectrum and gel permeation chromatograph. The average molecular weight of the principal component of this compound was 1,300-1,400. (Dispersant 1). 
     REFERENTIAL EXAMPLES 2 TO 12 
     Various phosphoric triester compounds were prepared in the same manner as in Referential Example 1, except that the reactants were replaced by those which are shown in Table 1 below. 
     
                       TABLE 1______________________________________No.  Reactants              (I)*   (II)**______________________________________2    (Dispersant 2)Mixture of dodecyl and tridecyl esters                       3      1300-1400of ricinoleic acidPhosphorus oxychloride 33    (Dispersant 3)Stearyl ester of 12-hydroxy-stearic acid                       3      1600-1700Phosphorus oxychloride 34    (Dispersant 4)Methyl ester of 12-hydroxy-                       3       900-1000stearic acidPhosphorus oxychloride 35    (Dispersant 5)Methyl ester of ricinolic acid                       3       900-1000Phosphorus oxychloride 36    (Dispersant 6)Mixture of tetracosyl and hexacosyl                       3      1800-2000esters of 12-hydroxy-stearic acidPhosphorus oxychloride 37    (Dispersant 7)Mixture of theracosyl and hexacosyl                       3      1800-2000esters of ricinolic acidPhosphorus oxychloride 38    (Dispersant 8)Butyl ester of 12-hydroxy-                       3      1000-1100stearic acidPhosphorus oxychloride 39    (Dispersant 9)Butyl ester of ricinoler acid                       3      1000-1100Phosphorus oxychloride 310   (Dispersant 10)Methyl ester of ε-hydroxy-caproic acid                       3      400-500Phosphorus oxychloride 311   (Dispersant 11)12-hydroxy-stearic acid                       3      800-900Phosphorus oxychloride 312   (Dispersant 12)Ricinolic acid         3      800-900Phosphorus oxychloride 3______________________________________ *Amount of the reactants (in equivalents) **Average molecular weight of the principal component of the resulting phosphate triester. 
    
     REFERENTIAL EXAMPLE 13 
     Into a four-mouth glass reactor (the same one as used in in Referential Example 1) equipped with a stirrer, thermometer, dropping funnel, and reflux condenser were charged 14.2 parts of phosphorus oxychloride. 92.8 parts of mixture of dodecyl and tridecyl esters of 12-hydroxystearic acid having 502 of gram epuivalent, which had been mixed with and dissolved in 92.8 parts of benzene and 17.4 parts of pyridine, was slowly added dropwise at 5° to 10° C. over 2 hours. The reaction was carried out at 10° C. for 1 hour. Further, 32.3 parts of the methyl ester of 12-hydroxystearic acid having 351 of gram equivalent, which had been mixed with and dissolved in 32.3 parts of benzene and 8.8 parts of pyridine, were slowly added dropwise at 10° to 20° C., over 1 hour. The reaction mixture was gradually raised to 80° C. over 3 hours and the reaction was carried out for 2 hours at 80° C. with stirring. Finally, the reaction product was cooled. 
     The equivalent ratio of the mixture of dodecyl and tridecyl esters the methyl ester, phosphorus oxychloride, and pyridene was 2:1:3:3.6. 
     The cooled reaction product was filtered washed, purified, dried, concentrated, and desolvated in the same manner as in Referential Example 1. Thus there was obtained a pale brown liquid. 
     The reaction product was identified as a phosphoric triester of the alkyl ester and methyl ester of poly-12-hydroxystearic acid in the same way as in Referential Example 1. The average molecular weight of the principal component of the principal component of this compound was about 1,200-1,300 (Dispersant 13). 
     REFERENTIAL EXAMPLE 14 TO 20 
     Various phosphoric triester compounds were prepared in the same manner as in Referential Example 13, except that the reactants were replaced by those which are shown in Table 2 below. 
     
                       TABLE 2______________________________________No.  Reactants              (I)*   (II)**______________________________________14   (Dispersant 14)Mixture of dodecyl and tridecyl esters                       2      1200-1300of ricinoleic acidMethyl ester of ricinolic acid                       1Phosphorus oxychloride 315   (Dispersant 15)Mixture of tetracosyl and hyxacosyl                       2      1600-1700esters of 12-hydroxyl-stearic acidButyl ester of 12-hydroxy-stearic acid                       1Phosphorus oxychloride 316   (Dispersant 16)Mixture of tetracosyl and heyacoxyl                       2      1600-1700ester of rinoleic acidButyl ester of rinoleic acid                       1Phosphorus oxychloride 317   (Dispersant 17)Mixture of dodecyl and tridecyl esters                       2      1000-1100of 12-hydroxy-stearic acidDecyl alcohol          1Phosphorus oxychloride 318   (Dispersant 18)Mixture of dodecyl and decyl esters                       2      1000-1100of inoleic acidOleyl alcohol          1Phosphorus oxychloride 319   (Dispersant 19)Mixture of odecyl and tridecyl esters                       1      800-900of 12-hydroxy-stearic acidDodecyl alcohol        2Phosphorus oxychloride 320   (Dispersant 21)Mixture of dodecyl and tridecyl esters                       1       900-1000of rinoleic acidOleyl alcohol          2Phosphorus oxychloride 3______________________________________ *Amount of the reactants (in equivalents) **Average molecular weight of the principal component of the resulting phosphoric triester. 
    
     REFERENTIAL EXAMPLE 21 
     Synthesis of a Phosphoric Diester Compound 
     A four-month glass reactor equipped with a stirrer, thermonerer, dropping funnel, and reflux condenser was provided. The reflux condenser was connected to a safety bottle and a bydrogen chloride gas absorbing bottle which was further connected to a vacuum pump and mercury manometer. 
     In the reactor were charged 3.0 parts of phosphorus oxychloride. The dropping fulled was filled with 98.8 parts of a mixtyre of dodecyl and trideoyl esters of 12-hydroxy-esteric acid (1 gram equivalent=505) and 98.8 parts of benzene as a solvent. 
     With the reactor cooled with iced water, the benzene solution was added dropwise at 5° to 10° C. The reactants were stirred at 10° C. for 1 hour. The reactor was gradually evacuated while increasing the reaction temperature. Hydrogen chloride gas formed by the reaction was absorbed by an aqueous solution of sodium hydroxide filled in the absorbing bottle. The reaction temperature was gradually raised to 40° C. and the reaction system was gradually evacuated to 100 mmHg over 5 hours. When the evolution of hydrogen chloride gas was not noticed any longer, the reaction system was cooled. In this state, the reaction system contains phosphoric (alkyl ester of 12-hydroxystearic acid) monoester dichloride. The dropping funnel was filled with 98.8 parts of the above-mentioned alkyl ester, 98.8 parts of benzene, and 19.8 parts of triethylamine, followed by mixing and dissolution. The resulting solution was added dropwise at 10° to 20° C. to the reactor over 60 minutes, followed by stirring for 2 hours. The reaction temperature was raised to 40° C. over 2 hours, and stirring was continued for 2 hours. The reactor was cooled. 
     The equivalent ratio of the alkyl ester of 12-hydoxy stearic acid, phosphorus oxychloride, and triethylamine was 2:3:1. 
     The reaction liquid was washed with water, a dilute aqueous solution of sodium hydroxide, a dilute aqueous solution of the hydrochloric acid, and water, for the dechlorination (hydrolysis) of phosphoric ester chloride and removal of chloride and the removal of triethylamine hydrochloride. The washed benzene layer was dried with sodium sulfate, and benzene was distilled away under reduced pressure. Thus there was obtained a pale brown liquid reaction product. 
     It was confirmed by infrared absorption spectrum and gel permeation chromatograph that the reaction product is composed mainly of a phosphoric diester compound of the alkyl ester of 12-hydroxystearic acid. (Dispersant 21). 
     The average molecular weight of the principal component was 900 to 1,000. 
     REFERENTIAL EXAMPLE 22 TO 32 
     Various phosphoric diester compounds were prepared in the same manner as in Referential Example 21, except that the reactants were replaced by those which are shown in Table 3 below. 
     
                       TABLE 3______________________________________No.  Reactants              (I)*   (II)**______________________________________22   (Dispersant 22)Mixture of decyl and tridecyl esters of                       2       900-1000ricinoleic acidPhosphorus oxychloride23   (Dispersant 23)Stearyl ester of 12-hydroxy-stearic acid                       2      1050-1150Phosphorus oxychloride 324   (Dispersant 24)Methyl ester of 12-hydroxy-                       2      600-700stearic acidPhosphorus oxychloride 325   (Dispersant 25)Methyl ester of ricinolic acid                       2      600-700Phosphorus oxychloride 326   (Dispersant 26)Mixture of tetracosyl and heyacoxyl                       2      1250-1350esters of 12-hydroxy-stearic acidPhosphorus oxychloride 327   (Dispersant 27)Mixture of tetracosy and heyacoxyl                       2      1250-1350esters ricinolic acidPhosphorus oxychloride 328   (Dispersant 28)Butyl ester of 12-hydroxy-                       2      700-780stearic acidPhosphorus oxychloride 329   (Dispersant 29)Butyl ester of ricinoleic acid                       2      700-780Phosphorus oxychloride 330   (Dispersant 30)Methyl ester of ε-hydroxy-                       2      320-350caproic acidPhosphorus oxychloride 331   (Dispersant 31)12-hydroxy-stearic acid                       2      600-650Phosphorus oxychloride 332   (Dispersant 32)Ricinolic acid         2      600-650Phosphorus oxychloride 3______________________________________ *Amount of the reactants (in equivalents) **Average molecular weight of the principal component of the resulting phosphate diester. 
    
     REFERENTIAL EXAMPLE 33 
     Into the same four-mouth glass reactor as used in Referential Example 21, which was equipped with a stirrer, thermometer, dropping funnel, evacuating system, and hydrogen chloride gas absorber, was charged 30 parts of phosphorus oxychloride. 
     The dropping funnel was filled with 98.8 parts of mixture of dodecyl and tridecyl esters of 12-hydroxy stearic acid hameng 505 of gramequivalent) and 98.8 parts of benzene as a solvent. The reaction was carried out in the same manner as in Referential Example 21 to give phosphoric (alkyl ester of 12-hydroxystearic acid) monoester dichloride. Then, 68.6 parts of the methyl ester of 12-hydroxystearic acid (gram equivalent=351) was mixed with and dissolved in 68.6 parts of benzene and 19.8 parts of triethylamine. The reaction was carried out in the same manner as in Referential Example 21. 
     The equivalent ratio of alkylestero mixture, methyl ester phosphorus oxychloride, and triethylamine was 1:1:3:1. 
     After cooling, the reaction liquid underwent dechlorination (hydrolysis), washing, purification, drying, concentration, and desolvation in the same manner as in Referential Example 21. Thus there was obtained a brown liquid reaction product. 
     It was confirmed by infrared absorption spectrum and gel permeation chromatograph that the reaction product is composed mainly of a phosphoric diester of mixtur alkyl esters of 12-hydroxystearie acid and methyl ester of 12-hydroxystearic acid. (Dispersant 33). 
     The average molecular weight of the principal component was about 800 to 850. 
     REFERENTIAL EXAMPLES 34 TO 40 
     Various phosphoric diester and monoester compounds were prepared in the same manner as in Referential Example 33, except that the reactants were replaced by those which are shown in Table 4 below. 
     
                       TABLE 4______________________________________No.  Reactants              (I)*   (II)**______________________________________34   (Dispersant 34)Mixture of dodecyl and tridecyl esters                       1      800-850of ricinoleic acidMethyl ester of ricinolic acid                       1Phosphorus oxychloride 335   (Dispersant 35)Mixture of etracixyl and hexacoxyl                       1       950-1050esters of 12-hydroxy-stearic acidButyl ester of 12-hydreostearic acid                       1Phosphorus oxychloride 336   (Dispersant 36)Mixture of tetracosyl and hexacosyl                       1       950-1050ester of ricinoleic acidButyl ester of ricinoleic acid                       1Phosphorus oxychloride 337   (Dispersant 37)Mixture of dodecyl and tridecyl esters                       1      650-720of 12-hydroxy-stearic acidDedecyl alcohol        1Phosphorus oxychloride 338   (Dispersant 38)Mixture of dodecyl and tridecyl esters                       1      700-800of ricinoleic acidOleyl alcohol          1Phosphorus oxychloride 339   (Dispersant 39)Mixture of dodecyl and tridecyl esters                       1      500-560of 12-hydroxy-stearicDodecyl alcohol        1Phosphorus oxychloride 340   (Dispersant 40)Mixture of dodecyl and tridecyl esters                       1      500-560of ricinoleic acidPhosphorus oxychloride 3______________________________________ *Amount of the reactants (in equivalents) **Average molecular weight of the principal component of the resulting phosphate diester or monoester. 
    
     EXAMPLE 1 
     Into a flusher were charged 238 parts of an aqueous filter cake (pigment content=42%) of copper phthalocyanine blue pigment (C.I. pigment Blue 15-3). To the flusher were further added 60 parts of Dispersant 1 (obtained in Referential Example 1) dissolved in 40 parts of a petroleum ink solvent. Flushing was carried out by mixing in the usual way. As compared with the conventional flushing agent, the dispersant in this example more readily freed water from the cake and transferred the copper phthalocyanine blue pigment to the oily dispersant phase. 
     After complete removal of water, there was obtained a flushed color containing copper phthalocyanine blue pigment. This flushed color was made into an offset litho ink according to the following formulation. 
     
         ______________________________________Flushed color (pigment = 50%)                   38.0   partsLitho varnish           60.0   parts5% cobalt drier         0.2    parts8% manganese drier      1.0    partsInk solvent             0.8    partsTotal                   100.0  parts______________________________________ 
    
     The litho varnish is formulated as follows: 
     
         ______________________________________Rosin-modified phenolic resin                    35.0   partsDrying oil               25.0   partsDrying oil-modified isophthalic acid alkyd                    10.0   partsInk solvent              29.5   partsAluminum chelator        0.5    partsTotal                    100.0  parts______________________________________ 
    
     The ink thus prepared was used offset printing on uncoated printing paper. There was obtained a printed matter of bright cyan color. 
     A flushed color was prepared in the same manner as above from an aqueous filter cake (pigment content=27%) of disazo yellow pigment (C.I. pigment yellow 12) and an aqueous filter cake (pigment content=25%) of brilliant carmine 6B pigment (C.I pigment red 57-1). The flushed color was made into a yellow and a magenta offset litho ink. 
     A flushed color was prepared in the same manner as above from an aqueous filter cake of lake red C pigment (C.I. pigment red 53-1), and the flushed color was made into a bronze red offset litho ink. A flushed color was also prepared from an aqueous filter cake of copper phthalocyanine green pigment (C.I. pigment green 7), and the flushed color was made into a green offset litho ink. 
     The dispersant readily freed water in the flushing operation and readily transferred the pigment to the oil phase. In addition, the flushed color was easily made into inks and the resulting inks gave a printed matter of bright color in offset litho printing. 
     When tested as mentioned above, Dispersants 2 to 20 also produced the same effect as Dispersant 1. 
     EXAMPLE 2 
     Using Dispersant 1 obtained in Referntial Example 1, carbon black pigment was mixed with the dispersed into varnish on a three-roll mill according to the following formulation. 
     
         ______________________________________Carbon black pigment   20    partsDispersant 1           6     partsOffset litho ink varnish                  69    partsTotal                  95    parts______________________________________ 
    
     The resulting carbon black dispersion was made into a carbon black ink by uniform mixing according to the following formulation. 
     
         ______________________________________Carbon black dispersion                  95.0   parts5% cobalt drier        0.2    parts8% manganese drier     1.0    partsInk solvent            3.8    partsTotal                  100.0  parts______________________________________ 
    
     The ink thus prepared was used for offset printing to give a printed matter of high balckness. When tested as mentioned above, Dispersants 2 to 19 also produced the same effect as Dispersant 1. 
     The yellow ink, magenta ink, cyan ink, and black ink prepared in this example were used as a four-color process ink for offset litho printing to give a bright beautiful multicolor printed matter. 
     EXAMPLE 3 
     A blue quick drying enamel (air drying type) for metallic materials (e.g., machines and vehicles) was produced according to the following formulation. 
     
         ______________________________________Flushed color (pigment = 50%) of copper                     10.8   partsphthalocyanine blue obtained in Example 1Rutile titanium white     2.0    partsFast drying styrenized alkyd resin                     72.6   partsXylene                    6.6    partsMineral spirit            7.6    parts6% cobalt naphthenate     0.3    partsAntiskinning agent        0.1    partsTotal                     100.0  parts______________________________________ 
    
     The resulting enamel provided bright beautiful coatings. 
     Flushed colors were prepared in the same manner as in Example 1 from an aqueous filter cake of disazo yellow pigment (C.I pigment yellow 14), fast yellow pigment (formed by coupling acetoacetanilide by diazotizing 4-aminophthalimide), watchung red pigment (C.I. pigment red 48), and carmine FB pigment (C.I. pigment red 3). The flushed colors were made into paints of varied colors according to the above-mentioned formulation. The paints gave bright beautiful coated plates. 
     EXAMPLE 4 
     A dispersion of copper phthalocyanine blue (C.I. pigment blue 15-3) in a xylene-butanol mixed solvent was prepared by dispersing the pigment using a continuous horizontal medium dispersing machine according to the following formulation. 
     
         ______________________________________Copper phthalocyanine blue pigment                       10    parts(dried and pulverized)Dispersant 1 obtained in Referential Example 1                       2     partsXylene                      13    partsButanol                     5     partsTotal                       30    parts______________________________________ 
    
     The resulting dispersion was made into an acrylic lacquer enamel for automobiles according to the following formulation. 
     
         ______________________________________Solvent dispersion above-mentioned                   3.0    partsRutile titanium white   14.0   partsThermoplastic acrylic resin                   70.0   partsToluene                 6.8    partsXylene                  3.2    partsButanol                 2.2    partsCellosolve              0.8    partsTotal                   100.0  parts______________________________________ 
    
     The resulting enamel provided bright beautiful coatings. 
     When tested as mentioned above, Dispersants 2 to 20 also produced the same effect as Dispersant 1. 
     EXAMPLE 5 
     Into a flusher were charged 238 parts of an aqueous filter cake (pigment content=42%) of copper phthalocyanine blue pigment (C.I. pigment blue 15-3) and 60 parts of the amine salt of Dispersant 21 dissolved in 40 parts of a petroleum ink solvent. (The amine salt was prepared by neutralizing the phosphoric acid radical of Dispersant 21 with about one equivalent of rosin amine.) Flushing was performed in the usual way. As compared with known flushing agents, the amine salt of Dispersant 20 more readily freed water from the filter cake and more readily transferred the copper phthalocyanine blue pigment to the oily dispersant phase. 
     After the complete removal of water, there was obtained a flushed color containing copper phthalocyanine blue pigment. The resulting flushed color was made into an offset litho printing ink according to the following formulation. 
     
         ______________________________________Flushed color (pigment content = 50%)                    38.0   partsOffset litho ink varnish 60.0   parts5% cobalt drier          0.2    parts8% manganese drier       1.0    partsInk solvent              0.8    partsTotal                    100.0  parts______________________________________ 
    
     The litho varnish was formulated as follows: 
     
         ______________________________________Rosin-modified phenolic resin                    35.0   partsDrying oil               25.0   partsDrying oil-modified isophthalic acid alkyd                    10.0   partsInk solvent              29.5   partsAluminum chelator        0.5    partsTotal                    100.0  parts______________________________________ 
    
     The ink thus prepared was used for offset printing on uncoated printing paper. There was obtained a printed matter of bright cyan color. 
     A flushed color was prepared in the same manner as above from avn aqueous filter cake (pigment content=27%) of disazo yellow pigment (C.I. pigment yellow 12) and an aqueous filter cake (pigment content=25%) of brilliant carmine 6B pigment (C.I. pigment red 57-1). The flushed color was made into a yellow and a magenta offset litho ink. 
     A flushed color was prepared in the same manner as above from an aqueous filter cake of lake red C pigment (C.I. pigment red 53-1), and the flushed color was made into a bronze red offset litho ink. A flushed color was also prepared from an aqueous filter cake of copper phthalocyanine green pigment (C.I. pigment green 7), and the flushed color was made into a green offset litho ink. 
     The dispersant readily freed watrer in the flushing operation and readily transferred the pigment to the oil phase. In addition, the flushed color was easily made into inks and the resulting inka gave a printed matter of bright in offset litho printing. 
     When tested as mentioned above, Dispersants 21 to 39 also produced the same effect as Dispersant 21. 
     The same superior effect as mentioned above was produced when the dispersant was neutralized with coconut amine, beef tallow propylene diamine, or hydroxides of calcium, strontium, or aluminum, in place of rosin amine. 
     EXAMPLE 6 
     Using Dispersant 21 obtained in Referential Example 21, carbon black pigment was mixed with and dispersed into varnish on a three-roll mill according to the following formulation. 
     
         ______________________________________Carbon black pigment     20    partsBeef tallow propylene diamine salt of                    6     partsDispersant 21Offset litho ink varnish 69    partsTotal                    95    parts______________________________________ 
    
     The resulting carbon black dispersion was made into a carbon black ink by uniform mixing according to the following formulation. 
     
         ______________________________________Carbon black dispersion                  95.0   parts5% cobalt drier        0.2    parts8% manganese drier     1.0    partsInk solvent            3.8    partsTotal                  100.0  parts______________________________________ 
    
     The ink thus prepared was used for offset printing to give a printed matter of high blackness. When tested as mentioned above, Dispersants 22 to 40 also produced the same effect as Dispersant 21. 
     The same superior effect as mentioned above was produced when the dispersant was neutralized with rosin amine, coconut amine, coconut propylene diamine, or hydroxide of calcium, strontium, or aluminum in place of beef tallow propylene diamine. 
     The yellow ink, magenta ink, cyan ink, and black ink prepared in this example were used as a four-color process ink for offset litho printing to give a bright beautiful multicolor printed matter. 
     EXAMPLE 7 
     A blue quick drying enamel (air drying type) for metallic materials (e.g., machines and vehicles) was produced according to the following formulation. 
     
         ______________________________________Flushed color (pigment = 50%) of copper                    10.8   partsphthalocyanine blue obtained in Example 5Rutile titanium white    2.0    partsFast drying styrenized alkyd resin                    72.6   partsXylene                   6.6    partsMineral spirit           7.6    parts6% cobalt naphthenate    0.3    partsAntiskinning agent       0.1    partsTotal                    100.0  parts______________________________________ 
    
     The resulting enamel provided bright beautiful coatings. 
     Flushed colors were prepared in the same manner as in Example 5 from an aqueous filter cake of disazo yellow pigment (C.I. pigment yellow 14), fast yellow pigment (formed by coupling acetoacetanilide by diazotizing 4-aminophthalimide), watchung red pigment (C.I. pigment red 48), and carmine FB pigment (C.I. pigment red 3). The flushed colors were made into paints of varied colors according to the above-mentioned formulation. The paints gave bright beautiful coate plates. 
     EXAMPLE 8 
     A dispersion of copper phthalocyanine blue (C.I. pigment blue 15-3) in a xylene-butanol mixed solvent was prepared by dispersing the pigment using a continuous horizontal medium dispersing machine according to the following formulation. 
     
         ______________________________________Copper phthalocyanine blue pigment                     10    parts(dried and pulverized)Salt of Dispersant 21 obtained in Referential                     2     partsExample 21 (neutralized with about oneequivalent of triethylamine)Xylene                    13    partsButanol                   5     partsTotal                     30    parts______________________________________ 
    
     The resulting dispersion was made into an acrylic lacquer enamel for automobiles according to the following formulation. 
     
         ______________________________________Solvent dispersion above-mentioned                   3.0    partsRutile titanium white   14.0   partsThermoplastic acrylic resin                   70.0   partsToluene                 6.8    partsXylene                  3.2    partsButanol                 2.2    partsCellosolve              0.8    partsTotal                   100.0  parts______________________________________ 
    
     The resulting enamel provided bright beautiful coatings. 
     When tested as mentioned above, Dispersants 22 to 40 also produced the same effect as Dispersant 21. 
     The same superior effect as mentioned above was produced when the dispersant was neutralized with rosin amine, coconut amine, beef tallow propylene diamine, coconut propylene diamine, or hydroxide of calcium, strontium, or aluminum, in place of triethylamine.