JPH0346168B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a pigment dispersion that uses a novel dispersant and has excellent dispersibility and dispersion stability.

Conventionally, in solution-type paints or inks containing pigments, problems such as difficulty in dispersion of pigments during production, agglomeration and sedimentation of pigments during storage, and resulting reduction in the coloring effect of painted surfaces, flatding, and floating (floating) have been observed. It is known that undesirable phenomena such as mottling), decrease in gloss, and discoloration over time occur. Various improvement methods have been attempted to solve these problems. For example, (1) a method of dispersing pigments using a nonionic, anionic, or cationic surfactant, or a wetting agent such as an aliphatic polycarboxylic acid as an aid; (2) British Patent Nos. 1108261 and 1159252;
and (3) a method of dispersing pigments using an amphiphilic substance in which a pigment-compatible substance and a medium-compatible substance are combined, as disclosed in No. 1346298, etc.; There are known methods to reduce this and prevent the occurrence of floating.

However, the above-mentioned conventional methods cannot sufficiently improve the above-mentioned drawbacks, and on the contrary, the disadvantages caused by the various additives mentioned above used in the conventional methods, that is, secondary problems such as deterioration of coating film performance or coating condition. The negative effects could not be avoided.

Therefore, an object of the present invention is to provide a pigment dispersion in which a stable pigment dispersion can be easily obtained without deteriorating the coating performance and coating condition.

The object of the present invention is to provide a pigment dispersion comprising a pigment, a dispersant, and an organic dispersion medium, in which the dispersant contains (1)
It is a reaction product of an amino resin and a silane coupling agent, (2) a reaction product of an alkyd resin and a silane coupling agent, or (3) a reaction product of an acrylic resin and a silane coupling agent. This is achieved by the pigment dispersion of the present invention.

The silane coupling agent used in the synthesis of the pigment dispersion of the present invention is RSi(OX) _4-o Y _o-1 [n is 1 to
An integer of 3. X is an alkyl group having 1 to 18 carbon atoms, a phenyl group, or -R'・OR''(R' is an alkyl group having 2 or 3 carbon atoms, R'' is an alkyl group having 1 to 18 carbon atoms)
An alkoxy/alkyl group represented by Y is an alkyl group having 1 to 18 carbon atoms. R is an epoxy group, an amino group, a urea group, a mercapto group, a halogen atom, or an organic residue having an ethylenically unsaturated double bond. The following compounds may be used.

γ-aminopropyltriethoxysilane, N-
Amino group-containing silane compounds such as β-(aminoethyl)-γ-aminopropyltrimethoxysilane and N-β-(aminoethyl)-γ-propylmethyldimethoxysilane. A urea group-containing silane compound such as γ-ureidopropyltriethoxysilane. γ-
Mercapto group-containing silane compounds such as mercaptoethyltriethoxysilane and γ-mercaptopropyltrimethoxysilane. γ-glycidoxypropyl trimethoxysilane, γ-glycidoxypropyl dimethylethoxysilane, γ-glycidoxypropyl methyldiethoxysilane, β-
Epoxy group-containing silane compounds such as (3,4-epoxycyclohexyl)ethyltrimethoxysilane. A halogen atom-containing silane compound such as γ-chloropropyltrimethoxysilane. Vinyltrimethoxysilane, vinyltriethoxysilane, vinyl tris(2-methoxy ethoxy)silane,
Ethylenically unsaturated group-containing silane compounds such as vinyltriacetoxysilane, vinyltriphenoxysilane, and γ-methacryloxypropyltrimethoxysilane. These organofunctional silanes can be used alone or as a mixture of two or more.

The amino resins used in the synthesis of the dispersants used in the present invention include amino group-containing resins commonly used in paint vehicles, specifically amino group-containing compounds such as urea, melamine or benzoguanamine, and formaldehyde. and ether-type amino resins obtained by modifying these with alcohols such as n- or iso-butanol. The dispersant obtained by the reaction of an amino resin and a silane coupling agent has a curing function through crosslinking, just like ordinary amino resins.
It has the advantage that even if it remains in the coating film, it hardly deteriorates the coating film performance.

The alkyd resin used in the synthesis of the dispersant used in the present invention refers to an ester type polycondensate that is crosslinkable at room temperature or under heat and is generally used as a paint vehicle. ), oil- or fatty acid-modified alkyd resins, phenolic resin-modified alkyd resins, rosin-modified alkyd resins, and styrenated alkyd resins.

As the acrylic resin used in the synthesis of the dispersant used in the present invention, one or more polymers or copolymers of the unsaturated monomers listed below can be used. Examples of these include esters of (meth)acrylic acid and linear, branched or cyclic monoalcohols having 1 to 26 carbon atoms; hydroxyalkyl (meth)acrylates, e.g.
-Hydroxyethyl (meth)acrylate, 2-
Hydroxymethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, etc.; Glycidyl (meth)acrylate or its adduct with a carboxylic acid having 1 to 26 carbon atoms; Unsaturated amides such as (meth)acrylamide, N-alkyl ( C1-4) Acrylamide; a polymer of acrylic monomers such as (meth)acrylic acid, a copolymer of two or more types of acrylic monomers, or one type of these acrylic monomers or two or more, and a polymerizable unsaturated nitrile, such as (meth)
such as acrylonitrile; ethylenically unsaturated aromatic compounds such as styrene, α-methylstyrene or vinyltoluene; polymerizable carboxylic acids,
Examples include itaconic acid, maleic acid, etc.; copolymers with vinyl compounds other than those mentioned above, such as vinyl acetate, vinyl chloride, etc., and diene compounds, such as butadiene, isoprene, and other polymerizable unsaturated monomers.

The above-mentioned dispersant consists of an alkoxysilane group as a pigment-compatible component, and an amino resin, alkyd resin, and acrylic resin moiety that are solvated in the solvent of the dispersion system as media-compatible components. When used for dispersion, the alkoxysilane groups react and adsorb to the hydroxyl groups (including adsorbed water) on the surface of the pigment, and the remaining components are solvated with the solvent, thus making the pigment particles extremely stable in the dispersion. It is presumed that the storage stability and coating condition will be significantly improved.

As the pigment used in the present invention, any of those commonly used in commercially available paints, inks, plastics, etc. can be used. for example,
Inorganic pigments include those mainly composed of simple elements such as carbon black and aluminum powder;
Zn, Pb, Ti, Sb, Cd, Fe, As, Sb, Mg, Al,
There are oxides, sulfates, sulfides, chromates, silicates, hydroxides, carbonates, etc. of Ba, Ca, Si, Co, Cr, etc. Organic pigments include natural dye pigments,
Nitroso pigments, nitro pigments, azo pigments, phthalocyanine pigments, basic dye pigments, and quinacridone red, quinacridone violet, perylene red, perylene scarlet, dioxazine violet, isoindolinone yellow, etc. It will be done. The amount of the pigment as exemplified above is preferably 80% by weight or less of the pigment dispersion; if it exceeds 80% by weight, it may become difficult to handle due to increased viscosity. In selecting these pigments, it is desirable to avoid pigments that cause undesirable side reactions during mixing with the resin.

The organic solvent used as a dispersion medium in the present invention can be arbitrarily selected as long as it does not react with the silane coupling agent. For example, aromatic systems such as xylene, toluene, and solvent naphtha, aliphatic systems such as hexane, mineral spirits, and ethylcyclohexane, ethyl acetate, and acetic acid n
Examples include ester solvents such as -butyl and cellosolve acetate. Furthermore, the addition of an alcoholic solvent such as methyl alcohol, ethyl alcohol, or n-butyl alcohol has the effect of suppressing excessive reactivity of the alkoxysilane group and preventing gelation.

When synthesizing the dispersant of the present invention, 1 to 100 parts by weight, preferably 2 to 50 parts by weight of a silane coupling agent is reacted with 100 parts by weight of an amino resin, alkyd resin or acrylic resin.

If the silane coupling agent is less than 1 part by weight, the amount of alkoxysilane adsorbed to the pigment surface will be small and the adsorption effect will be small; if it exceeds 100 parts by weight, the amount of amino resin, alkyd resin, etc. that will be solvated, The amount of acrylic resin is small, resulting in poor dispersion stability. The reaction temperature of the amino resin, alkyd resin, or acrylic resin and the silane coupling agent is not particularly limited, but is preferably 50 to 120°C, and the reaction progress is controlled by the state of increase in the viscosity of the product during the reaction process. be able to. If necessary, reaction catalysts such as paratoluenesulfonic acid, phosphoric acid, tertiary amines such as triethylamine, and quaternary ammonium salts such as tetraethylammonium chloride may be used. If the reaction progresses too much, the reaction of the alkoxysilane groups may occur, resulting in gelation, so care must be taken.

A fine and stable pigment dispersion can be easily obtained by diluting the dispersant used in the present invention with any of the above-mentioned dispersion mediums (organic solvents), mixing with any pigment, and performing a dispersion operation using a known method. In the production of the above dispersion, known coating resins such as amino resins, alkyd resins, polyester resins, epoxy resins, acrylic resins, polyvinyl chloride, polyvinyl acetate, polystyrene, polybutadiene, rosin, ester gums or cellulose derivatives are used. can be mixed into the pigment dispersion of the present invention. In this case, in order to obtain a fine pigment dispersion, the addition rate of the pigment dispersion is preferably 1% by weight or more based on the above-mentioned resin solid content. Further, a large amount of dispersant is used for pigments with a large specific surface area such as carbon black, and a small amount is used for pigments with a small specific surface area such as titanium oxide.

Examples of devices used for dispersion include sheakers, roll mills, colloid mills, ball mills,
Examples include sand grinders and attritors.

By using a surface tension modifier such as a silicone type agent in the pigment dispersion of the present invention, it is possible to further suppress floating and floating phenomena.

The invention will now be explained in detail with reference to examples. "Parts" and "%" in the examples are "parts by weight" and "% by weight," respectively.

Example 1 60% isobutanol modified melamine resin liquid (A) 100
When 6 parts of the silane coupling agent KBM-603 (manufactured by Shin-Etsu Chemical Co., Ltd., N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane) were heated and stirred at 85°C for 3 hours, the bubble viscosity changed from U to Z. The pigment dispersant was colored a pale orange-red color.

When this product was analyzed by infrared spectroscopy, it was found that the absorption intensity of amino groups and methylol groups was reduced compared to a simple mixture of melamine resin (A) and silane coupling agent.

Dispersant [] is xylol/n-butanol=
Dilute to 1/1 (weight ratio) to a solid content of 25%, put this in a mayonnaise bottle, and add rutile type titanium white 120.
and 60 parts for 12 parts of furnace type carbon black.
150 parts of 4 mm diameter hard alumina beads were further added to each of them, and dispersed using a sheaker for 1 hour in the case of titanium white and 2 hours in the case of carbon black. After dispersion, add 24 parts of the pigment dispersant [ ] to the titanium white paste and 30 parts to the carbon black paste and mix to form stabilized titanium white paste (C) and carbon black paste (D), respectively. Obtained. Furthermore, 140 parts of titanium white paste (C) contains 87.5% of 60% coconut oil fatty acid modified alkyd resin liquid.
29.2 parts of 60% melamine resin liquid (A) were added to form a paint, and the above carbon black paste (D) was added to obtain a gray paint (E).

As a result of analyzing the pastes (C) and (D) using a rotating centrifugal particle size distribution analyzer, the median particle size of titanium white was
0.35μ, carbon black has a median particle size of 0.08μ
It was hot.

For pastes (C) and (D), the weight ratio of titanium white/carbon black contained in them is 10/1 ~
Mixed in various ways within the range of 1/10, xylene/n
The mixed pigment was diluted to 1% by volume with a solvent of -butanol=1/1 (weight ratio) and placed in a test tube, but the dispersion state was stable for a long time at any blending ratio.

The above paint (E) was applied to a steel plate using a roll coater and a bar coater. The dispersion state of the pigment in the paint, especially carbon black, was improved, and as a result, the black color development in the gray paint color was improved, and the gloss of the paint surface was also excellent.

Furthermore, there was no difference in the degree of black color development between roll coater painting and bar coater painting, and no difference in color development due to changes in shear speed of the coating machine was observed.

Furthermore, when the paint (E) was stored indoors for one month and then painted using the same method, there was almost no difference in color from the paint color that was applied immediately after preparation.

Comparative Example 1 In place of the dispersant [ ], 60% isobutanol-modified melamine resin liquid (A) was diluted to a solid content of 25% and tested under the same formulation and dispersion conditions as in Example 1. The median particle size of
0.47μ, the median particle size of carbon black is
It was 0.2μ.

In addition, in the in-examiner sedimentation test, the black layer and white layer were completely separated and settled early, and even when applied using the coating method of Example 1, the black color development was inferior to that of Example 1. The degree of color development was significantly different between the case where the paint was applied with a roll coater and the case where the paint was applied with a roll coater due to the difference in shear rate.

Example 2 48 parts of the above 25% pigment dispersant [] was added to 120 parts of red iron oxide, and 48 parts to 24 parts of copper phthalocyanine blue.
Add 60 parts and add 4mmφ alumina beads to each
150 parts were added and dispersed using a sheaker for 1 hour for Red Garla and 2 hours for Copper Phthalocyanine Blue. The median particle size of Red Garla paste is 0.18μ,
In copper phthalocyanine blue paste, it was dispersed down to 0.16μ.

Further, in the same manner as in Example 1, the sedimentation stability was tested, and as a result, a stable dispersion state was maintained for a long time.

For comparison, when a 60% isobutanol-modified melamine resin solution (A) diluted to a solid content of 25% was used for dispersion, the diameters were 0.85μ and 12μ, respectively.

Example 3 60% isobutanol modified melamine resin liquid (A) 100
When 6 parts of silane coupling agent A-1100 (manufactured by Nippon Unicar Co., Ltd., γ-aminopropyltriethoxysilane) was added to 1 part and heated at 85°C for 4 hours and 20 minutes, a pigment dispersion whose bubble viscosity increased from N to P to Q was obtained. The agent [] was obtained.

This dispersant [] was diluted to a solid content of 25% with a solvent of xylene/n-butanol = 1/1 (weight ratio),
Rutile-type titanium white and furnace-type carbon black were dispersed using the same composition and dispersion conditions as in Example 1, and a sedimentation test in a test tube and a test regarding coating color were conducted. As a result, the dispersion state was stable for a long time. , the coloring power was large and the impetus force was large, and the degree of color development was very uniform even when coating was performed by changing the shear speed as described above.

Example 4 Add 6 parts of silane coupling agent KBM-603 to 100 parts of 60% benzoguanamine resin solution (B) and heat at 85°C.
When heated and stirred for 4 hours, a dispersant [] whose bubble viscosity increased from B ⁺ to E ⁺ was obtained. When this dispersant [] was tested in the same way as the dispersants [] and [], it was found to have excellent pigment dispersion ability, similar to the results of Examples 1 and 3.

Example 5 100 parts of 50% soybean oil modified alkyd resin liquid (oil length 41%, acid value 5) and silane coupling agent A-1120 [manufactured by Nippon Unicar Co., Ltd., N-β-(aminoethyl)-γ]
-Aminopropyltrimethoxysilane] 5 parts to 90
When heated and stirred at ℃ for 3 hours, the bubble viscosity increased from O to T, and a pale reddish-orange colored pigment dispersant was obtained.

Dispersant [] is xylene/n-butanol=
Dilute to 1/1 (weight ratio) to a solid content of 25%, and put this in a mayonnaise bottle and add 48 parts to 120 parts of rutile-type titanium white, and 48 parts to 120 parts of rutile-type titanium white, and 48 parts to 120 parts of rutile-type titanium white,
For 12 parts, 60 parts were added and mixed, and 150 parts of each of the 4 mm diameter hard alumina beads were further added and dispersed using a sheaker for 1 hour in the case of titanium white and 2 hours in the case of carbon black. . After the dispersion was completed, 24 parts of 50% soybean oil-modified alkyd resin liquid was added to the titanium white paste and 30 parts to the carbon black paste to obtain stabilized titanium white and carbon black pastes, respectively.
When the particle sizes of these pastes were analyzed using a rotating centrifugal particle size distribution analyzer, the median particle size was 0.34μ for titanium white and 0.09μ for carbon black. Similarly to Example 1, pastes were prepared by varying the ratio of titanium white/carbon black, and the mixed pigment was diluted with a solvent of xylene/n-butanol = 1/1 (weight ratio) to 1 volume. When the mixture was left standing in a test tube, the dispersion state remained stable for a long period of time at any blending ratio.

50% for 140 parts of stabilized titanium white paste
87.5 parts of a soybean oil-modified alkyd resin solution and 29.2 parts of a 60% butanol-modified melamine resin solution were added to form a paint, and the above stabilized carbon black paste was added to this to obtain a gray paint. The coating color of the coated board prepared from the gray paint by the coating method of Example 1 was good in terms of both black color development and gloss, and the degree of black color development was also good even when applied in the same manner as described above while changing the shear speed. was uniform. Further, after storage under the same conditions as in Example 1, there was no difference in coating color over time.

Comparative Example 2 The 50% soybean oil-modified alkyd resin liquid used in Example 5 was diluted to 25% solid content in place of the dispersant [ ], and a test was conducted under the same formulation and dispersion conditions as in Example 5. , the median particle size of titanium white is
0.42μ, the median particle size of carbon black is
It was 0.25μ. In addition, in the in vitro sedimentation test, the black layer and white layer completely separated and settled early, and the degree of color development of the black coating was inferior to that of Example 5, and the degree of color development did not respond to changes in shear rate during coating. It has changed significantly.

Example 6 The above dispersant [] was added to 120 parts of red iron oxide
48 parts, copper phthalocyanine blue - 60 for 24 parts
Add 150 parts of 4mmφ hard alumina beads to each of them, and leave for 1 hour for red iron and 2 hours for copper phthalocyanine blue.
Dispersed using a time sheaker. Red iron has a median particle size of 0.18μ, and copper phthalocyanine blue has a median particle size of 0.18μ.
It was dispersed down to 0.09μ.

In addition, sedimentation stability and coating color tests were conducted in the same manner as in Example 5, and the dispersion state was stable for a long time and good color development was obtained.

For comparison, when a 50% soybean oil-modified alkyd resin solution diluted to a solid content of 25% was used for dispersion instead of the dispersant, the values were 0.52μ and 0.35μ, respectively.

Example 7 60% phenol-modified alkyd resin liquid (oil length 52
%, acid value 4.6) 100 parts of silane coupling agent A-
When 10 parts of 1160 (manufactured by Nippon Unicar Co., Ltd., γ-ureidopropyltriethoxysilane) was added and stirred at 80°C for 3 hours, the bubble viscosity increased from U to Y.
A pigment dispersant colored pale orange was obtained.

Dispersant [] is xylene/n-butanol=
It was diluted with a 1/1 (weight ratio) solvent so that the solid content was 25%, and rutile-type titanium white and furnace-type carbon black were dispersed under the same formulation and dispersion conditions as in Example 5, and subjected to the test. As a result, in a sedimentation test in a test tube, the dispersion state is stable for a long time, and the coating color has a high degree of color development and has a large invading force, and even when coating with varying shear speeds, a very uniform degree of color development can be obtained. Ta.

Example 8 55% acrylic resin liquid A (copolymer with monomer composition of 20 parts of styrene, 50 parts of 2-ethylhexyl methacrylate, 10 parts of 2-hydroxyethyl methacrylate, 17 parts of methyl methacrylate, and 3 parts of methacrylic acid, number average molecular weight approx. 1.2×10 ⁴ ) 100
10 parts of silane coupling agent A-1160 (manufactured by Nippon Unicar Co., Ltd., γ-ureidopropyltriethoxysilane) was added to the mixture, and when heated and stirred at 80°C for 3 hours, the bubble viscosity increased from W to Z, and the color turned pale orange. A colored pigment dispersant [] was obtained.

Dispersant [] is xylene/n-butanol=
Dilute 25% of the solid content to 1/1 (weight ratio) and place it in a mayonnaise bottle as rutile type titanium white 120.
and 60 parts for 12 parts of furnace type carbon black.
150 parts of 4 mm diameter hard alumina beads were further added to each of them, and dispersed using a sheaker for 1 hour in the case of titanium white and 2 hours in the case of carbon black. After the dispersion was completed, 24 parts of 50% acrylic resin liquid A was added to the titanium white paste and 30 parts to the carbon black paste to obtain stabilized titanium white and carbon black pastes, respectively. When the particle sizes of these pastes were analyzed using a rotating centrifugal flow distribution measuring device, titanium white had a median particle size of
It was 0.32μ, and carbon black was 0.10μ. In addition, pastes were prepared by varying the ratio of titanium white/carbon black as in Example 1, and diluted with a solvent of xylene/n-butanol = 1/1 (weight ratio) so that the mixed pigment was 1% by volume. When the mixture was left to stand in a test tube, the dispersion state remained stable for a long time at any blending ratio.

To 140 parts of the above stabilized titanium white paste, 87.5 parts of 55% acrylic resin liquid A and 29.2 parts of 60% butanol modified melamine resin liquid were added to form a paint, and the above stabilized carbon black paste was added to this. Obtained gray paint. The paint color created using the gray paint in the same manner as in Example 1 was as follows:
Both black color development and gloss were good, and no difference in color development was observed even when coating was performed with varying shear speeds. Moreover, after storing according to the method of Example 1,
There was no change in paint color over time.

Comparative Example 3 When the 55% acrylic resin liquid A used in Example 8 was diluted to 25% solid content in place of the dispersant [ ] and tested under the same formulation and dispersion conditions as Example 8, it was found that titanium The median particle size of white was 0.41μ, and the median particle size of carbon black was 0.32μ.
In addition, in the in-examiner sedimentation test, the black layer and white layer were completely separated and settled early, and the color development of the black coating was inferior to that of Example 8, and the color development was affected by changes in shearing speed during painting. has changed significantly.

Example 9 Add 48 parts of a pigment dispersant [] with a solid content of 25% to 120 parts of red iron oxide and 60 parts to 24 parts of copper phthalocyanine blue, and further add 150 parts of 4 mmφ alumina beads to each. Dispersion was carried out using a sheaker for 1 hour in the case of Red Red Garla and 2 hours in the case of Copper Phthalocyanine Blue. Red iron has a median particle size of 0.20μ, and copper phthalocyanine blue has a median particle size of 0.12μ.
It was dispersed until

Further, a sedimentation stability test was conducted in the same manner as in Example 8, and the dispersion state was stable for a long time.

For comparison, when 55% acrylic resin liquid A diluted to a solid content of 25% was used instead of the dispersant [ ] and dispersed, the values were 0.79μ and 0.90μ, respectively.

Example 10 55% acrylic resin liquid B (methyl methacrylate
30 parts of butyl methacrylate, 20 parts of N-methylolmethacrylamide, 8 parts of 2-hydroxyethyl acrylate, and 2 parts of acrylic acid, number average molecular weight approximately 9 x 10 ³ )
Add 10 parts of silane coupling agent KBE-903 (manufactured by Shin-Etsu Chemical Co., Ltd., γ-aminopropyltriethoxysilane) to 100 parts and heat at 85°C for 2 hours. The bubble viscosity increases from X to Z ₂ , and the color turns pale orange. A colored pigment dispersant [] was obtained. The dispersant was diluted to a solid content of 25% with a xylene/n-butanol = 1/1 (weight ratio) solvent, and rutile type titanium and furnace type carbon black were dispersed using the same formulation and method as in Example 8. In the sedimentation test in a test tube, the dispersion was stable for a long time, and the black color was well developed when applying gray paint, and the impetus force was large and the shear speed was changed. A uniform color was obtained.

Claims (1)

[Scope of Claims] 1. Consists of a pigment, a dispersant, and an organic dispersion medium, and the dispersant is (a) an amino resin; (b) the general formula RSi(OX) _4-o Y _o-1 , where n is is an integer of 1 to 3; X is an alkyl group having 1 to 18 carbon atoms, a phenyl group, or -
R′OR″ (where R′ represents an alkyl group having 2 or 3 carbon atoms, R″ represents an alkyl group having 1 to 18 carbon atoms); Y represents an alkoxyalkyl group having 1 to 18 carbon atoms; Represents an alkyl group; R represents an epoxy group, an amino group, a urea group, a mercapto group, a halogen atom, or an organic residue having an ethylenically unsaturated double bond. A pigment dispersion liquid characterized by: 2 Dispersant is (a) for 100 parts by weight of amino resin, (b)
The pigment dispersion according to claim 1, which is a reaction product obtained by reacting 1 to 100 parts by weight of a silane coupling agent. 3 Comprised of a pigment, a dispersion liquid, and an organic dispersion medium, the dispersant being (a') an alkyd resin, (b) general formula RSi(OX) _4-o Y _o-1 , where n is an integer from 1 to 3. and X is an alkyl group having 1 to 18 carbon atoms, a phenyl group, or -
R′OR″ (where R′ represents an alkyl group having 2 or 3 carbon atoms, R″ represents an alkyl group having 1 to 18 carbon atoms); Y represents an alkoxyalkyl group having 1 to 18 carbon atoms; Represents an alkyl group; R represents an epoxy group, an amino group, a urea group, a mercapto group, a halogen atom, or an organic residue having an ethylenically unsaturated double bond. A pigment dispersion liquid characterized by: 4. Claim 3, wherein the dispersant is a reaction product obtained by reacting 100 parts by weight of (a') alkyd resin with 1 to 100 parts by weight of (b) the silane coupling agent. pigment dispersion. 5 Comprising a pigment, a dispersant, and an organic dispersion medium, the dispersant being (a″) an acrylic resin, (b) general formula RSi(OX) _4-o Y _o-1 , where n is an integer from 1 to 3 and X is an alkyl group having 1 to 18 carbon atoms, a phenyl group, or -
R′OR″ (where R′ represents an alkyl group having 2 or 3 carbon atoms, R″ represents an alkyl group having 1 to 18 carbon atoms); Y represents an alkoxyalkyl group having 1 to 18 carbon atoms; Represents an alkyl group; R represents an epoxy group, an amino group, a urea group, a mercapto group, a halogen atom, or an organic residue having an ethylenically unsaturated double bond. A pigment dispersion liquid characterized by: 6. Claim 5, wherein the dispersant is a reaction product obtained by reacting 100 parts by weight of (a″) acrylic resin with 1 to 100 parts by weight of (b) a silane coupling agent. pigment dispersion.