JPH107983A - Coating composition and pigment dispersant - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a coating composition excellent in pigment dispersibility and dispersion stability by using a high-monoester-content polyglycerol fatty acid monoester synthesized from a fatty acid and glycidol as the pigment dispersant. SOLUTION: This composition contains a polyglycerol fatty acid monoester in which the content (in terms of a peak area ratio) of a fatty acid monoester represented by formula I (wherein R is a 6-21 C alkyl, an alkenyl or a hydroxyl- substituted alkyl; and n is 4 or greater) and detected by using an ultraviolet absorption detector in column chromatography is 70% or higher. The polyglycerol fatty acid monoester is obtained by reacting a fatty acid represented by formula II (wherein R is as defined in formula I) with glycidol in the presence of a phosphoric acid catalyst.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to various printing ink compositions and various paints such as flat inks, gravure inks and flexographic inks (these are collectively referred to as coating compositions).
And a pigment dispersant used therefor.

[0002]

BACKGROUND ART In a coating composition such as a printing ink or a coating material, a practically useful pigment which exhibits a vivid color tone, high coloring power, and excellent gloss generally comprises fine particles. However, when fine pigment particles are dispersed in non-aqueous vehicles such as offset inks, gravure inks and paints, it is difficult to obtain a dispersion having excellent fluidity and storage stability, and the production process and the resulting product It often causes various problems that have a significant effect on the quality of the product. For example, a dispersion containing a pigment composed of fine particles often exhibits a high viscosity, which makes it difficult to remove and transport the product from the disperser, or that the ink composition becomes extremely thick during storage and becomes difficult to use. Sometimes. Further, undesirable phenomena such as flooding (color separation), floating (uneven color), reduction in gloss, and aging change occur.

[0003] In recent years, polyglycerin fatty acid esters have been approved as food additives, and their use has been gradually increasing. In general, this ester can be used as a raw material to obtain an ester having a wide range of HLB values by combining polyglycerin having different degrees of polymerization with fatty acids having different chain lengths, and exhibit high stability in an acidic region. In the field, it is widely used as an emulsifier and a viscosity modifier. The method for producing the polyglycerin fatty acid ester includes (1) an esterification reaction between polyglycerin and a fatty acid, (2) a transesterification reaction between polyglycerin and a fatty acid ester, (3) a transesterification reaction between polyglycerin and a fat or oil, There are (4) an addition polymerization reaction of glycidol and a fatty acid monoglyceride, and (5) an addition polymerization reaction of glycidol and a fatty acid.

The method (1) is based on JAOCS (Journal of A).
American 0il Chemists' Society) Vol. 58, No. 878
(1981) discloses a method for obtaining a polyglycerin fatty acid ester by performing an esterification reaction of polyglycerin and a fatty acid in the presence of an alkali catalyst. A similar method is disclosed in Japanese Patent Application Laid-Open No. 6-41007.

The methods (2) and (3) are reactive,
This is a method with many restrictions on the quality, purity, etc. of the produced polyglycerin fatty acid ester. For method (4),
No. 4,515,775. Regarding the method (5), mono-fatty acid esters of glycerin are described in JP-A-51-65705. However, according to the disclosed technique, a high percentage of carboxylic acid-1-monoglyceride (in the formula [1], the value of n is 1 on average) is produced in the presence of an inert solvent. No mention is made of polyglycerol monofatty acid esters at all, and no actual study has been made. Also,
JP-A-8-109153 discloses that a fatty acid represented by the following general formula [2] is reacted with glycidol in the presence of a phosphoric acid-based catalyst, and a general formula [1] described below.
The method for producing a polyglycerin monofatty acid ester having a high content of a monofatty acid ester derivative represented by the formula (1) is described.

[0006]

Many attempts have been made in the past to solve the above-mentioned problems relating to coating compositions such as ink compositions and paints, and such attempts have been recognized to some extent. Have been. For example,
JP-A-34-0909 discloses a dispersant relating to a polyester having a terminal carboxyl group or a salt thereof obtained by dehydrating a hydroxycarboxylic acid such as 12-hydroxystearic acid, and JP-A-54-37082. Discloses a method for preparing a pigment dispersion for the production of an ink comprising the reaction product of the polyester and a poly (lower alkylene) imine. Further, JP-A-64-2433
In the publication, polyoctamethylene polyamine and poly (12
Dispersants comprising reaction products with polyesters having terminal carboxyl groups (such as -hydroxystearic acid) are described. JP-A-6-9913 describes a dispersant comprising an ester of a condensed hydroxy fatty acid having a degree of condensation of at least 2 or more and a polyhydric alcohol. That is, hydroxy fatty acids such as ricinoleic acid, 12-hydroxystearic acid, and dihydroxystearic acid; alkane polyols such as pentaerythritol and glycerin; and sugars such as sucrose;
Examples thereof include esters of saccharide derivatives such as phenol and mannitol, and esters of polyalkane polyols such as di- or tripentaerythritol and polyglycerin. Despite the various attempts described above, a dispersant having sufficiently satisfactory performance in the effect of pigment dispersion has not been obtained.

In the method (1), not only the desired monoester but also unreacted polyglycerol, diester, triester, tetraester and the like are generally contained in the produced polyglycerol fatty acid ester. When used as a pigment dispersing agent material, the performance over time and the effect of dispersing pigments cannot be said to be sufficiently satisfactory due to the effect of these residues. The necessity was found by the inventors' examination.

The above-mentioned Japanese Patent Application Laid-Open No. 8-109153 does not disclose the use of the resulting polyglycerol monofatty acid ester as a pigment dispersant in inks and paints.

[0009]

[Means for Solving the Problems] In view of such circumstances,
As a result of intensive studies on the pigment dispersant of the coating composition, a polyglycerol monofatty acid ester having a high monoester content, synthesized from a fatty acid and glycidol, was used as a nonelectrolyte surfactant. As a result, the inventors have found that the above-mentioned drawbacks of the prior art can be improved, and have completed the present invention.

That is, according to the present invention, the content of a monofatty acid ester represented by the following general formula [1], which is detected by a column chromatography analysis method using an ultraviolet absorption detector, as a peak area ratio is 70% or more. The present invention relates to a coating composition comprising a polyglycerin monofatty acid ester.

[0011]

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In the coating composition, the polyglycerol monofatty acid ester is obtained by reacting a fatty acid represented by the following general formula [2] with glycidol in the presence of a phosphoric acid-based catalyst. Is preferred.

[0013]

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[0014] The present invention further relates to a pigment dispersant for a coating composition comprising the above-mentioned polyglycerol monofatty acid ester. Hereinafter, the configuration of the present invention will be described in detail.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION The polyglycerol monofatty acid ester used as a pigment dispersant in the coating composition of the present invention comprises:
Specifically, preferably, an alcohol solvent such as methanol or ethanol and / or distilled water is used as an eluent, for example, an octadecyl group-bonded silica gel column (OD
High Performance Liquid Chromatography (HP Column)
LC), and the content of the monofatty acid ester represented by the general formula [1] is analyzed by an analytical method (column chromatography analysis) in which detection is performed using an ultraviolet absorption detector. 70% or more in terms of ratio,
The production method is preferably a method obtained by reacting glycidol with a fatty acid represented by the general formula [2] in the presence of a phosphoric acid-based catalyst.

The column chromatography analysis refers to a reverse phase distribution column analysis using silica gel to which octadecylsilyl, octylsilyl, butylsilyl, trimethylsilyl, and phenylsilyl groups are bonded as functional groups, and aminopropyl groups as functional groups. , A normal phase distribution column analysis method using silica gel having a cyanopropyl group, an ion exchange column analysis method using a silica gel having a quaternary ammonium group and a phenylsulfonic acid group as a functional group, and an adsorption column analysis method using a porous silica gel. . Of these, a reversed-phase distribution column analysis method using silica gel to which the octadecylsilyl group is bonded is preferably used.

The peak area ratio of the monofatty acid ester is 7
Specifically, 0% or more means that the peak area ratio attributed to the monofatty acid ester is 70% or more based on the peak area of all the esters under the following HPLC analysis conditions. I do.

Preferred conditions for HPLC are as follows: an ODS column, which is a reverse-phase partitioning column, is used as a column to be used;
As the column size, 4.6 mmφ × 250 mm or more is used, and more preferably, the analysis conditions are such that the columns used are connected in series to increase the separation capacity.

The developing solvent varies depending on the type of polyglycerin fatty acid ester. That is, it depends on the number of moles of the fatty acid or glycidol used, and it is preferable to determine the developing solvent depending on the solubility and separation of the test sample. Alcohol-based solvents and / or distilled water are preferred as specific developing solvents having excellent solubility and separation properties of the specimen. More specifically, methanol is used for polyglycerol laurate, and stearic acid is used. Preferably, ethanol is used for the polyglycerol ester.

The flow rate of the developing solvent can be selected depending on the pressure resistance of the column to be used and the degree of separation of the obtained chromatogram, and is usually from 0.05 ml / min to 1.0 ml.
ml / min, more preferably 0.1 ml / min.
It is set in the range of 1 ml / min to 0.8 ml / min. It is preferable to use a column oven in order to maintain the column to be used at a constant temperature. The temperature of the oven is usually raised to a temperature higher than room temperature in order to improve the resolving power of the column to be used. It is set in the range of 60 ° C. The wavelength of the ultraviolet absorption detector is usually 210 nm.

Further, as for the sample to be used for HPLC, it is preferable to use a developing solution to be used as a solvent, and it is preferable to select a concentration and an injection amount which are excellent in the solubility and separation of the analyte. Specifically, as the sample concentration,
1% to 50% is preferable, and the injection volume is 0.1 μl to
20 μl is preferred. The determination of the unsubstituted polyglycerin component, monoester component, and diester or higher polysubstituted ester component was performed by HPLC analysis of the corresponding polyglycerin, fatty acid monoglyceride, and diglyceride standard products under the same conditions as follows. Determined.
For example, in the case of separation by high performance liquid chromatography using an octadecylsilyl group-bonded silica gel column,
First, it was determined that a highly polar unsubstituted polyglycerin component was detected, and then a highly polar polyglycerin monofatty acid ester was detected. At this time, the elution order of the polyglycerin monofatty acid ester starts to be detected from the monoester of polyglycerin having a higher degree of polymerization and higher polarity, and the last polyglycerol monofatty acid ester to be detected is the monoglycerol monofatty acid ester. It was determined to be an ester form. Further, those detected after the monoester of glycerin are determined to be polysubstituted ester components of diester or higher. Accordingly, the calculation of the monoesterification rate (content of the monofatty acid ester) was performed as follows. That is, the peak area of the polyglycerin component detected first, the peak area from the start of detection of the polyglycerin monofatty acid ester to the detection of the monoester form of glycerin, and the peak area detected after the monoester form of glycerin From the peak area and the peak area of the solvent alone equal to the sample injection amount, the following formula: (monoesterification rate) = ｛(peak from the first detection of polyglycerin monofatty acid ester until the detection of monoester of glycerin) Area) / [(sum of peak areas of all components)-(peak area of solvent only)]｝ × 100
(%). Note that the peak position of the solvent alone has a retention time of that solvent,
It is also important to select a solvent so that it does not extend over the above three components (unsubstituted polyglycerin component, monoester component, and diester or higher polysubstituted ester component). The above formula is based on the premise that the retention time of the solvent is in the diester or higher polysubstituted ester component,
The formula may be different depending on the peak position. H
Typical analysis conditions of PLC are as follows.

<HPLC Analysis Conditions (Part 1)> Column: Wakosil 5C18 × 2 (manufactured by Wako Pure Chemical Industries, Ltd .: column having an octadecylsilyl group as a functional group, which is a reversed-phase distribution column, size: 4.6 mmφ) × 2
50 mm), developing solvent: methanol, flow rate: 0.75 m
1 / min. , Column oven temperature: 40 ° C., detection method: ultraviolet absorption method (λ = 210 nm), sample concentration: 10
% (Solvent: methanol), injection volume: 5 μl. For example, in the case of polyglycerin monolaurate, the retention time of each component is 8 minutes or less for polyglycerin, 8 to 12 minutes for monolaurate, and 12 minutes or more for dilaurate or more.

<HPLC Analysis Conditions (Part 2)> Column: Wakosil II 5C18HG (manufactured by Wako Pure Chemical Industries, Ltd .: column having an octadecylsilyl group as a functional group, which is a reversed-phase distribution column, size: 4.6 mm)
φ × 250 mm), developing solvent: methanol, flow rate: 0.
2 ml / min. , Column oven temperature: 40 ° C., detection method: ultraviolet absorption method (λ = 210 nm), sample concentration: 5
% (Solvent: methanol), injection volume: 10 μl, retention time of each component was polyglycerin: before 14 minutes,
Monoester: 14 to 16.5 minutes, Diester and higher: 16.5 minutes and thereafter, methanol component: 18 minutes.

<HPLC Analysis Conditions (Part 3)> Column: Wakosil 5C18 and Wakosil
II 5C18HG (all manufactured by Wako Pure Chemical Industries, Ltd .:
(A column having an octadecylsilyl group as a functional group, which is a reversed-phase distribution column, size: 4.6 mmφ × 250 mm)
Are connected in series. Developing solvent: ethanol, flow rate:
0.2 ml / min. , Column oven temperature: 40 ° C,
Detection method: UV absorption method (λ = 210 nm), sample concentration: 5% (solvent: EtOH), injection amount: 10 μl. Retention time of each component is polyglycerin: 2
Before 8.5 minutes, monoester: 28.5 minutes to 34 minutes,
Diester or higher: after 34 minutes, ethanol component: 39
Minutes.

The fatty acid (RCOOH) used in the addition polymerization reaction of glycidol and the fatty acid to produce the polyglycerol monofatty acid ester used in the present invention is preferably a fatty acid having 7 to 22 carbon atoms, The fatty acid may be a fatty acid or an unsaturated fatty acid, a linear fatty acid, a fatty acid having a side chain, or a hydroxyl-substituted fatty acid. These fatty acids include, for example, caproic acid, caprylic acid, 2-ethylhexanoic acid,
Examples include capric acid, lauric acid, isotridecanoic acid, myristic acid, palmitic acid, palmitoleic acid, stearic acid, isostearic acid, oleic acid, linoleic acid, behenic acid, erucic acid, ricinoleic acid, and hydroxystearic acid. The reaction between the fatty acid and glycidol is preferably performed in the presence of a phosphoric acid acidic catalyst.

Examples of the phosphoric acid-based acidic catalyst include phosphoric acids and phosphoric acid esters, and specific examples thereof include phosphoric acid, phosphoric anhydride, polyphosphoric acid, orthophosphoric acid, metaphosphoric acid, pyrophosphoric acid, and triphosphoric acid. Phosphoric acids such as phosphoric acid and tetraphosphoric acid, and acid phosphates such as methyl acid phosphate, ethyl acid phosphate, isopropyl acid phosphate, butyl acid phosphate, 2-ethylhexyl acid phosphate, and the like can be used. In addition, as these acidic phosphates, any of a monoester body, a diester body, and a mixture thereof can be used. Of these, phosphoric acid or acidic phosphoric acid esters are preferably used.

One of the above catalysts may be used alone,
Also, two or more kinds may be used as a mixture. The amount of the catalyst is 0.01 to 10% by weight, preferably 0.1 to 5% by weight, based on the fatty acid. If the amount is less than 0.01% by weight, the reaction rate is small, and if it exceeds 10% by weight, no improvement in the effect can be expected. Depending on the catalyst used, a large amount of a glycidol addition polymer in which the catalyst is used as an initiator is formed. Absent.

The reaction method is to take fatty acids in a reaction vessel,
The above-mentioned soot is added thereto, and the reaction is carried out while adding glycidol little by little. The reaction temperature is 50-180 ° C, preferably 70-160 ° C, more preferably 120-180 ° C.
~ 140 ° C. Below 50 ° C., the reaction rate is low,
On the other hand, if the temperature exceeds 180 ° C., coloring becomes intense. If the temperature is higher than 230 ° C., glycidol is decomposed to cause a side reaction, which is not preferable. In this case, a low-boiling compound that does not react with glycidol may be added to prevent an increase in the reaction temperature. The reaction is desirably performed in a nitrogen gas atmosphere, and may be pressurized if necessary.

By the above reaction, glycidol is addition-polymerized to the fatty acid to produce a polyglycerol monofatty acid ester having a higher polymerization degree. The product is a polyglycerin monofatty acid ester having a high monofatty acid ester content. That is, the polyglycerol monofatty acid ester obtained as described above is contained in a column chromatography analysis method using a peak area ratio of the monofatty acid ester compound represented by the general formula [1], which is detected using an ultraviolet absorption detector. The rate is 70% or more. The polyglycerol monofatty acid ester having a high monoester content, synthesized from the above-described fatty acid and glycidol, can be used alone or in combination of two or more as a pigment dispersant of the coating composition of the present invention.

The ink composition as one kind of the coating composition of the present invention is an ink composition obtained by dispersing an inorganic or organic pigment in an organic liquid such as a gravure ink, a flat ink and a flexographic ink. Toluene as an organic liquid,
Aromatic hydrocarbons such as xylene, halogenated hydrocarbons such as mineral spirits, esters such as ethyl acetate, butyl acetate and amyl acetate, acetone, methyl ethyl ketone,
One or more mixed solvents of ketones such as cyclohexanone, etc., and a mixed system with a known pigment dispersant such as an alkyd resin, an epoxy ester resin, a melamine resin, an acrylic resin, a polyamide resin, and a vinyl resin. There is no problem.

The inorganic pigments include titanium dioxide, iron oxide, aluminum hydroxide, calcium carbonate, talc,
Examples thereof include carbon black and aluminum. Examples of the organic pigment include an azo pigment, a lake pigment, a toner, a phthalocyanine pigment, an isoindolinone pigment, and a quinacridone pigment. These pigments can be used alone or in combination of two or more, or in combination of an inorganic pigment and an organic pigment. The amount of the dispersant of the present invention is 0.1 to 100% by weight, preferably 0.1 to 100% by weight, based on the pigment or the like.
５０50% by weight. The content of the pigment in the organic liquid is 1 to 90% by weight, preferably 5 to 80% by weight.

One example of a method for preparing the ink composition of the present invention is as follows. First, one or more organic liquids are mixed as necessary, and then one or more pigments are used. Is added to the organic liquid, and mixed by stirring to disperse. The pigment dispersant comprising the polyglycerol monofatty acid ester of the present invention may be added at any point during these steps, but is preferably added to the organic liquid or pigment before adding the pigment to the organic liquid. More preferably, it is previously added to the organic liquid. The dispersion method is not particularly limited, but a stirring device such as a paint shaker or a ball mill is used, and the temperature during stirring and mixing is kept at room temperature to 100 ° C. After dispersing, cool if necessary. The ink composition of the present invention thus obtained has excellent color density,
The coating film exhibits gloss, fluidity, and storage stability and is not particularly limited, and can be used for, for example, a flat plate ink, a gravure ink, a flexographic ink, and the like.

In the case of the coating composition of the present invention, the pigment dispersant comprising the polyglycerol monofatty acid ester of the present invention is also prepared by the same formulation as the pigment dispersant conventionally used in various paints. It can be prepared by adding to a paint.

[0034]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the present invention is limited thereto.

REFERENCE EXAMPLE 1 0.5 mol (100.1 mol) of lauric acid was placed in a 1-liter four-necked flask equipped with a nitrogen inlet tube, a stirrer, a cooling tube, a temperature controller, and a dropping cylinder.
6g) and 0.0622g of phosphoric acid (85% product)
Heated to 40 ° C. Then, while maintaining the reaction temperature at 140 ° C., 3.0 mol (222.24 g) of glycidol was added dropwise over 5 hours. The temperature was further maintained, and the reaction was continued for 26 hours. After cooling, the reaction product was taken out to obtain about 300 g of hexaglycerin monolaurate. When the obtained polyglycerol monolaurate (hexaglycerol monolaurate) was evaluated according to the <HPLC analysis conditions (1)>, the monosubstitution rate was 87.7%.

Reference Example 2 4.0 mol of glycidol
(296.32 g) Except for using, the same operation as in Reference Example 1 was performed. After cooling, the reaction product was taken out to obtain about 400 g of octaglycerin monolaurate. The obtained polyglycerin monolaurate (octaglycerin monolaurate) was treated with H in the same manner as in Reference Example 1.
When evaluated by PLC, the mono substitution rate was 84.5%.

[Reference Example 3] Glycidol 5.0 mol
(370.40 g) The same operation as in Reference Example 1 was carried out except that the mixture was used. After cooling, the reaction product was taken out to obtain about 470 g of decaglycerin monolaurate. The obtained polyglycerol monolaurate (decaglycerin monolaurate) was subjected to HPL in the same manner as in Reference Example 1.
When evaluated by C, the mono substitution rate was 77.2%.

COMPARATIVE REFERENCE EXAMPLE 1 In the case of reaction between fatty acid and polyglycerin Polyglycerin (Daicel Chemical Co., Ltd.) was placed in a 1-liter four-necked flask equipped with a nitrogen inlet tube, stirrer, cooling tube, temperature controller, and dropping cylinder. Industrial Co., Ltd. PG
L06: hexaglycerin, hydroxyl value 960) 175.
3 g (0.5 mol) was taken, heated to 80 ° C., and while maintaining the reaction temperature at 80 ° C., 0.5 mol (10 mol) of lauric acid.
0.16 g) was added and dissolved. Next, 0.75 g of sodium carbonate and 0.25 g of sodium bisulfite were added, and an esterification reaction was performed at 210 ° C. After 2 hours of reaction, the acid value became 0.89 mgKOH / g. After cooling to 100 ° C., the reaction product was taken out. The obtained polyglycerol monolaurate was converted to HP
When evaluated by LC, the mono substitution rate was 55.1%.

Comparative Reference Examples 2 and 3: Evaluation Results of Commercially Available Polyglycerol Fatty Acid Esters As commercial polyglycerin fatty acid esters produced from the reaction of polyglycerin and fatty acids, two products of SY Glyster (manufactured by Sakamoto Yakuhin Kogyo) (ML-500, ML-750) were selected. When these polyglycerin monolaurates were evaluated by HPLC in the same manner as in Reference Example 1, ML-500,
The mono substitution rates of ML-750 were 52.0%, 4
4.3%. These are referred to as Comparative Reference Examples 2 and 3, respectively.

Example 1 Organic liquid: 60 parts of toluene, dispersant: 3 parts of the esterified product of Reference Example 1, pigment: phthalocyanine-37 parts In addition
The mixture was uniformly dispersed with a mill to obtain an ink composition. The ink composition exhibited good fluidity, and no viscosity increase or pigment sedimentation or separation was observed after standing for 10 days.

Example 2 An organic liquid: 38 parts of xylene, a dispersant: 2 parts of the esterified product of Reference Example 2, and a pigment: 60 parts of titanium dioxide, a dispersant was added to xylene, and then a pigment was added. And uniformly dispersed in a ball mill to obtain an ink composition. The ink composition exhibited good fluidity, and no viscosity increase or pigment sedimentation or separation was observed after standing for 10 days.

Example 3 An organic liquid: 50 parts of isophorone, a dispersant: 3 parts of the esterified product of Reference Example 3, and a pigment: 47 parts of iron oxide, a dispersant was added to isophorone, and then a pigment was added. And uniformly dispersed in a ball mill to obtain an ink composition. The ink composition exhibited good fluidity, and no viscosity increase or pigment sedimentation or separation was observed after standing for 10 days.

COMPARATIVE EXAMPLE 1 An organic liquid: 50 parts of isophorone, a dispersant: 3 parts of the esterified product of Comparative Reference Example 1, and a pigment: 47 parts of iron oxide. In addition, the mixture was uniformly dispersed in a ball mill to obtain an ink composition. The ink composition showed good fluidity, but thickening was observed after standing for 7 days.

Comparative Example 2 An organic liquid: xylene 38 parts, a dispersing agent: 2 parts of the esterified product of Comparative Reference Example 2, and a pigment: 60 parts of titanium dioxide. In addition, the mixture was uniformly dispersed in a ball mill to obtain an ink composition. The ink composition exhibited good fluidity, but after standing for 10 days, thickening or sedimentation and separation of the pigment were observed.

Comparative Example 3 Organic Liquid: 50 parts of isophorone, Dispersant: Comparative Example Reference Example 3
3 parts of esterified compound, pigment: 47 parts of iron oxide,
After adding a dispersant to isophorone, a pigment was added and the mixture was uniformly dispersed in a ball mill to obtain an ink composition. The ink composition showed good fluidity, but after standing for 7 days, thickening, sedimentation and separation of the pigment were observed.

[0046]

As is clear from the above examples, according to the pigment dispersant of the present invention, the dispersion efficiency of the pigment in the coating composition such as the ink composition can be improved and the pigment can be kneaded at a high pigment concentration. -Flood, floating, change in gloss due to stabilization of pigment dispersion,
It is clear that phenomena such as aging can be prevented.

Claims (10)

[Claims] 1. A content of a monofatty acid ester represented by the following general formula [1], which is detected by a column chromatography analysis method using an ultraviolet absorption detector, expressed as a peak area ratio of 70,
% Of polyglycerin monofatty acid ester which is at least 10% by weight. Embedded image 2. A polyglycerin monofatty acid ester,
Mono-fatty acid ester represented by the general formula [1], which is separated by high-performance liquid chromatography using an octadecylsilyl group-bonded silica gel column using an alcohol solvent and / or distilled water as an eluent and detected using an ultraviolet absorption detector The coating composition according to claim 1, wherein the content represented by the peak area ratio is 70% or more. 3. The coating composition according to claim 1, wherein R of the monofatty acid ester constituting the polyglycerin monofatty acid ester is an alkyl group having 6 to 21 carbon atoms. 4. A polyglycerol monofatty acid ester,
4. The coating composition according to claim 1, which is obtained by reacting a fatty acid represented by the following general formula [2] with glycidol in the presence of a phosphoric acid-based catalyst. Embedded image 5. The polyglycerol monofatty acid ester,
The coating composition according to claim 4, wherein R is a product obtained by reacting a fatty acid that is an alkyl group having 7 to 21 carbon atoms. 6. The coating composition according to claim 4, wherein the phosphoric acid acidic catalyst is phosphoric acid or an acidic phosphoric acid ester. 7. The coating composition according to claim 1, which is an ink composition. 8. The content of the monofatty acid ester represented by the following general formula [1], which is detected by a column chromatography analysis method using an ultraviolet absorption detector and represented by the peak area ratio, is 70%.
% Of a polyglycerol monofatty acid ester in a coating composition. Embedded image 9. The polyglycerol monofatty acid ester,
The monofatty acid ester represented by the general formula [1] is separated by high performance liquid chromatography using an octadecyl group-bonded silica gel column using an alcohol solvent and / or distilled water as an eluent and detected using an ultraviolet absorption detector. 9. The pigment dispersant for a coating composition according to claim 8, wherein the content represented by the peak area ratio is 70% or more. 10. The pigment dispersant for a coating composition according to claim 8, which is a pigment dispersant for an ink composition.